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Bioengineering, Volume 11, Issue 8 (August 2024) – 76 articles

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16 pages, 4489 KiB  
Article
Design and Validation of a PLC-Controlled Morbidostat for Investigating Bacterial Drug Resistance
by Adrián Pedreira, José A. Vázquez, Andrey Romanenko and Míriam R. García
Bioengineering 2024, 11(8), 815; https://doi.org/10.3390/bioengineering11080815 (registering DOI) - 10 Aug 2024
Viewed by 222
Abstract
During adaptive laboratory evolution experiments, any unexpected interruption in data monitoring or control could lead to the loss of valuable experimental data and compromise the integrity of the entire experiment. Most homemade mini-bioreactors are built employing microcontrollers such as Arduino. Although affordable, these [...] Read more.
During adaptive laboratory evolution experiments, any unexpected interruption in data monitoring or control could lead to the loss of valuable experimental data and compromise the integrity of the entire experiment. Most homemade mini-bioreactors are built employing microcontrollers such as Arduino. Although affordable, these platforms lack the robustness of the programmable logic controller (PLC), which enhances the safety and robustness of the control process. Here, we describe the design and validation of a PLC-controlled morbidostat, an innovative automated continuous-culture mini-bioreactor specifically created to study the evolutionary pathways to drug resistance in microorganisms. This morbidostat includes several improvements, both at the hardware and software level, for better online monitoring and a more robust operation. The device was validated employing Escherichia coli, exploring its adaptive evolution in the presence of didecyldimethylammonium chloride (DDAC), a quaternary ammonium compound widely used for its antimicrobial properties. E. coli was subjected to increasing concentrations of DDAC over 3 days. Our results demonstrated a significant increase in DDAC susceptibility, with evolved populations exhibiting substantial changes in their growth after exposure. Full article
21 pages, 1686 KiB  
Article
CellRegNet: Point Annotation-Based Cell Detection in Histopathological Images via Density Map Regression
by Xu Jin, Hong An and Mengxian Chi
Bioengineering 2024, 11(8), 814; https://doi.org/10.3390/bioengineering11080814 (registering DOI) - 10 Aug 2024
Viewed by 133
Abstract
Recent advances in deep learning have shown significant potential for accurate cell detection via density map regression using point annotations. However, existing deep learning models often struggle with multi-scale feature extraction and integration in complex histopathological images. Moreover, in multi-class cell detection scenarios, [...] Read more.
Recent advances in deep learning have shown significant potential for accurate cell detection via density map regression using point annotations. However, existing deep learning models often struggle with multi-scale feature extraction and integration in complex histopathological images. Moreover, in multi-class cell detection scenarios, current density map regression methods typically predict each cell type independently, failing to consider the spatial distribution priors of different cell types. To address these challenges, we propose CellRegNet, a novel deep learning model for cell detection using point annotations. CellRegNet integrates a hybrid CNN/Transformer architecture with innovative feature refinement and selection mechanisms, addressing the need for effective multi-scale feature extraction and integration. Additionally, we introduce a contrastive regularization loss that models the mutual exclusiveness prior in multi-class cell detection cases. Extensive experiments on three histopathological image datasets demonstrate that CellRegNet outperforms existing state-of-the-art methods for cell detection using point annotations, with F1-scores of 86.38% on BCData (breast cancer), 85.56% on EndoNuke (endometrial tissue) and 93.90% on MBM (bone marrow cells), respectively. These results highlight CellRegNet’s potential to enhance the accuracy and reliability of cell detection in digital pathology. Full article
(This article belongs to the Special Issue Artificial Intelligence-Based Diagnostics and Biomedical Analytics)
15 pages, 1141 KiB  
Article
Mathematical Modeling of the Gastrointestinal System for Preliminary Drug Absorption Assessment
by Antonio D’Ambrosio, Fatjon Itaj, Filippo Cacace and Vincenzo Piemonte
Bioengineering 2024, 11(8), 813; https://doi.org/10.3390/bioengineering11080813 (registering DOI) - 9 Aug 2024
Viewed by 196
Abstract
The objective of this study is to demonstrate the potential of a multicompartmental mathematical model to simulate the activity of the gastrointestinal system after the intake of drugs, with a limited number of parameters. The gastrointestinal system is divided into five compartments, modeled [...] Read more.
The objective of this study is to demonstrate the potential of a multicompartmental mathematical model to simulate the activity of the gastrointestinal system after the intake of drugs, with a limited number of parameters. The gastrointestinal system is divided into five compartments, modeled as both continuous systems with discrete events (stomach and duodenum) and systems with delay (jejunum, ileum, and colon). The dissolution of the drug tablet occurs in the stomach and is described through the Noyes–Whitney equation, with pH dependence expressed through the Henderson–Hasselbach relationship. The boluses resulting from duodenal activity enter the jejunum, ileum, and colon compartments, where drug absorption takes place as blood flows countercurrent. The model includes only three parameters with assigned physiological meanings. It was tested and validated using data from in vivo experiments. Specifically, the model was tested with the concentration profiles of nine different drugs and validated using data from two drugs with varying initial concentrations. Overall, the outputs of the model are in good agreement with experimental data, particularly with regard to the time of peak concentration. The primary sources of discrepancy were identified in the concentration decay. The model’s main strength is its relatively low computational cost, making it a potentially excellent tool for in silico assessment and prediction of drug adsorption in the intestine. Full article
(This article belongs to the Section Regenerative Engineering)
14 pages, 1009 KiB  
Article
Automated Lumen Segmentation in Carotid Artery Ultrasound Images Based on Adaptive Generated Shape Prior
by Yu Li, Liwen Zou, Jiajia Song and Kailin Gong
Bioengineering 2024, 11(8), 812; https://doi.org/10.3390/bioengineering11080812 (registering DOI) - 9 Aug 2024
Viewed by 179
Abstract
Ultrasound imaging is vital for diagnosing carotid artery vascular lesions, highlighting the importance of accurately segmenting lumens in ultrasound images to prevent, diagnose and treat vascular diseases. However, noise artifacts, blood residue and discontinuous lumens significantly affect segmentation accuracy. To achieve accurate lumen [...] Read more.
Ultrasound imaging is vital for diagnosing carotid artery vascular lesions, highlighting the importance of accurately segmenting lumens in ultrasound images to prevent, diagnose and treat vascular diseases. However, noise artifacts, blood residue and discontinuous lumens significantly affect segmentation accuracy. To achieve accurate lumen segmentation in low-quality images, we propose a novel segmentation algorithm which is guided by an adaptively generated shape prior. To tackle the above challenges, we introduce a shape-prior-based segmentation method for carotid artery lumen walls. The shape prior in this study is adaptively generated based on the evolutionary trend of vessel growth. Shape priors guide and constrain the active contour, resulting in precise segmentation. The efficacy of the proposed model was confirmed using 247 carotid artery ultrasound images, with experimental results showing an average Dice coefficient of 92.38%, demonstrating superior segmentation performance compared to existing mathematical models. Our method can quickly and effectively perform accurate lumen segmentation on low-quality carotid artery ultrasound images, which is of great significance for the diagnosis of cardiovascular and cerebrovascular diseases. Full article
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<p>Ultrasound images of carotid artery. The red lines represent the lumen walls.</p>
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<p>Generation process of the shape prior. (<b>a</b>) The original image. (<b>b</b>) Center line. (<b>c</b>) Shape prior.</p>
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<p>Comparison of the three methods on Dice metric.</p>
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<p>Comparison results in ultrasound images. (<b>a</b>) The original images. (<b>b</b>) Ground truth labeled by experienced physicians. (<b>c</b>–<b>e</b>) are the segmentation results of CV, DRLSE and the proposed model, respectively.</p>
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<p>Poor segmentation results of the proposed method. (<b>a</b>) The original images. (<b>b</b>) Ground truth. (<b>c</b>) Results of the proposed method.</p>
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11 pages, 12531 KiB  
Article
Effects of Exercise on the Inter-Session Accuracy of sEMG-Based Hand Gesture Recognition
by Xiangyu Liu, Chenyun Dai, Jionghui Liu and Yangyang Yuan
Bioengineering 2024, 11(8), 811; https://doi.org/10.3390/bioengineering11080811 - 9 Aug 2024
Viewed by 176
Abstract
Surface electromyography (sEMG) is commonly used as an interface in human–machine interaction systems due to their high signal-to-noise ratio and easy acquisition. It can intuitively reflect motion intentions of users, thus is widely applied in gesture recognition systems. However, wearable sEMG-based gesture recognition [...] Read more.
Surface electromyography (sEMG) is commonly used as an interface in human–machine interaction systems due to their high signal-to-noise ratio and easy acquisition. It can intuitively reflect motion intentions of users, thus is widely applied in gesture recognition systems. However, wearable sEMG-based gesture recognition systems are susceptible to changes in environmental noise, electrode placement, and physiological characteristics. This could result in significant performance degradation of the model in inter-session scenarios, bringing a poor experience to users. Currently, for noise from environmental changes and electrode shifting from wearing variety, numerous studies have proposed various data-augmentation methods and highly generalized networks to improve inter-session gesture recognition accuracy. However, few studies have considered the impact of individual physiological states. In this study, we assumed that user exercise could cause changes in muscle conditions, leading to variations in sEMG features and subsequently affecting the recognition accuracy of model. To verify our hypothesis, we collected sEMG data from 12 participants performing the same gesture tasks before and after exercise, and then used Linear Discriminant Analysis (LDA) for gesture classification. For the non-exercise group, the inter-session accuracy declined only by 2.86%, whereas that of the exercise group decreased by 13.53%. This finding proves that exercise is indeed a critical factor contributing to the decline in inter-session model performance. Full article
(This article belongs to the Section Biosignal Processing)
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<p>Electrode setup for the data collection. Numbers 1–4 denote the four <math display="inline"><semantics> <mrow> <mn>8</mn> <mo>×</mo> <mn>8</mn> </mrow> </semantics></math> electrode arrays placed on the forearm.</p>
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<p>Ten gestures used in the experiment: (1) wrist flexion, (2) wrist extension, (3) wrist radial, (4) wrist ulnar, (5) wrist pronation, (6) wrist supination, (7) hand close, (8) hand open, (9) thumb and index finger pinch, and (10) thumb and middle finger pinch.</p>
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<p>Two-dimensional heat map of muscle activation before and after exercise. Each map presents the RMS of sEMG signals. Brighter pixels denote more active muscle groups. For better visualization, the original <math display="inline"><semantics> <mrow> <mn>16</mn> <mo>×</mo> <mn>16</mn> </mrow> </semantics></math> maps are upsampled to <math display="inline"><semantics> <mrow> <mn>100</mn> <mo>×</mo> <mn>100</mn> </mrow> </semantics></math> via bicubic interpolation.</p>
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<p>Mean classification accuracies (%) within sessions for two groups. Statistical tests were conducted between the two groups for each session. ‘n.s.’ denotes that no statistical significance was found between exercise and non-exercise group.</p>
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<p>Mean classification accuracies (%) in the inter-session scenario for two groups. A statistical test was conducted between the two groups. ‘*’ denotes a significant difference between the two groups, with a <span class="html-italic">p</span>-value between 0.01 and 0.05.</p>
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<p>Confusion matrix for intra-session and inter-session gesture recognition. The numbers 1 to 10 represent the index of hand gestures shown in <a href="#bioengineering-11-00811-f002" class="html-fig">Figure 2</a>. Note that the value in row i and column j represents the probability that gesture i (i = 1, 2, …, 10) is recognized as gesture j (j = 1, 2, …, 10).</p>
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<p>The visualized data distribution of exercise group and non-exercise group. The bottom-right corner of the figure exhibits the centroid distances of the ten categories between two sessions for the exercise and non-exercise groups. A larger distance indicates a more significant deviation in data distribution between sessions. A <span class="html-italic">p</span>-value of less than 0.05 indicates that the data distribution deviation in the exercise group is significantly greater than that in the non-exercise group.</p>
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<p>Relationship between the increase in biceps circumference (%) and mean inter-session classification accuracy (%). Each red dot represents the mean accuracy for a specific increase in biceps circumference. The dotted line represents the fitted trend, and the shaded area indicates the confidence interval.</p>
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18 pages, 4149 KiB  
Article
Enhancing Dermatological Diagnostics with EfficientNet: A Deep Learning Approach
by Ionela Manole, Alexandra-Irina Butacu, Raluca Nicoleta Bejan and George-Sorin Tiplica
Bioengineering 2024, 11(8), 810; https://doi.org/10.3390/bioengineering11080810 - 9 Aug 2024
Viewed by 177
Abstract
Background: Despite recent advancements, medical technology has not yet reached its peak. Precision medicine is growing rapidly, thanks to machine learning breakthroughs powered by increased computational capabilities. This article explores a deep learning application for computer-aided diagnosis in dermatology. Methods: Using [...] Read more.
Background: Despite recent advancements, medical technology has not yet reached its peak. Precision medicine is growing rapidly, thanks to machine learning breakthroughs powered by increased computational capabilities. This article explores a deep learning application for computer-aided diagnosis in dermatology. Methods: Using a custom model based on EfficientNetB3 and deep learning, we propose an approach for skin lesion classification that offers superior results with smaller, cheaper, and faster inference times compared to other models. The skin images dataset used for this research includes 8222 files selected from the authors’ collection and the ISIC 2019 archive, covering six dermatological conditions. Results: The model achieved 95.4% validation accuracy in four categories—melanoma, basal cell carcinoma, benign keratosis-like lesions, and melanocytic nevi—using an average of 1600 images per category. Adding two categories with fewer images (about 700 each)—squamous cell carcinoma and actinic keratoses—reduced the validation accuracy to 88.8%. The model maintained accuracy on new clinical test images taken under the same conditions as the training dataset. Conclusions: The custom model demonstrated excellent performance on the diverse skin lesions dataset, with significant potential for further enhancements. Full article
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<p>Examples of clinical and dermoscopic images used for training.</p>
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<p>The architecture and the setup of the model.</p>
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<p>The validation accuracy and loss for the BCC, benign keratosis-like lesions. Melanocytic nevi and melanoma classes.</p>
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<p>The validation accuracy and loss for BCC, benign keratosis-like lesions, melanocytic nevi, melanoma, SCC, and AK classes.</p>
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<p>The ROC curve for the BCC, benign keratosis-like lesions, melanocytic nevi, and melanoma classes.</p>
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<p>The ROC curve for BCC, benign keratosis-like lesions, melanocytic nevi, melanoma, SCC, and AK classes.</p>
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<p>Confusion matrix for BCC, benign keratosis-like lesions, melanocytic nevi, and melanoma classes.</p>
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<p>Confusion matrix for BCC, benign keratosis-like lesions, melanocytic nevi, melanoma, SCC, and AK classes.</p>
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<p>Errors per class for BCC, benign keratosis-like lesions, melanocytic nevi, and melanoma classes.</p>
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<p>Errors per class for BCC, benign keratosis-like lesions, melanocytic nevi, melanoma, SCC, and AK classes.</p>
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9 pages, 2205 KiB  
Article
Intratumoral Chemotherapy: The Effects of Drug Concentration and Dose Apportioning on Tumor Cell Injury
by Jacob S. Warner, C. Matthew Kinsey, Jason H. T. Bates and Vitor Mori
Bioengineering 2024, 11(8), 809; https://doi.org/10.3390/bioengineering11080809 - 9 Aug 2024
Viewed by 256
Abstract
The addition of intravenous (i.v.) chemotherapy to i.v. immunotherapy for patients with lung cancer results in improved overall survival but is limited by synergistic side effects and an unknown, highly variable final cytotoxic dose within the tumor. The synergy between i.v. chemo- and [...] Read more.
The addition of intravenous (i.v.) chemotherapy to i.v. immunotherapy for patients with lung cancer results in improved overall survival but is limited by synergistic side effects and an unknown, highly variable final cytotoxic dose within the tumor. The synergy between i.v. chemo- and immunotherapies is hypothesized to occur as a result of cell injury caused by chemotherapy, a mechanism demonstrated to drive antigen presentation within the tumor microenvironment. Intratumoral delivery of chemotherapy may thus be optimized to maximize tumor cell injury. To assess the balance between the damage versus the death of tumor cells, we developed a computational model of intratumoral dynamics within a lung cancer tumor for three different chemotherapy agents following direct injection as a function of location and number of injection sites. We based the model on the morphology of a lung tumor obtained from a thoracic CT scan. We found no meaningful difference in the extent of tumor cell damage between a centrally injected versus peripherally injected agent, but there were significant differences between a single injection versus when the total dose was apportioned between multiple injection sites. Importantly, we also found that the standard chemotherapeutic concentrations used for intravenous administration were effective at causing cell death but were too high to generate significant cell injury. This suggests that to induce maximal tumor cell injury, the optimal concentration should be several orders of magnitude lower than those typically used for intravenous therapy. Full article
(This article belongs to the Special Issue Mathematical and Computational Modeling of Cancer Progression)
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<p>Tumor silhouette (blue) and drug deposition (red) shown with deformation modeled as homogenous expansion (<b>A</b>) and local expansion (<b>B</b>).</p>
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<p>Temporal relation between the % of tumor death over time when the drug is injected into the tumor. Blue line—homogenous tumor expansion, central injection; orange line—homogenous tumor expansion, off-center injection; green line—local expansion, central injection; red line—local expansion, off-center injection.</p>
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<p>Percent tumor damage (<b>top</b> row) and killing (<b>bottom</b> row) with cisplatin (<b>A</b>,<b>D</b>), doxorubicin (<b>B</b>,<b>E</b>), and etoposide (<b>C</b>,<b>F</b>) for both dose apportioning (blue) and single (orange) injection strategies. ANOVA testing was performed between doses for each combination of drug and injection strategy using standard intravenous concentrations for each drug as control (1 mg/mL for cisplatin, 2 mg/mL for doxorubicin, and 40 mg/mL for etoposide). Statistical differences are represented by *** (<span class="html-italic">p</span> &lt; 0.05). For each combination of drug and dose, differences between single and multiple injections strategies are represented by # (<span class="html-italic">p</span> &lt; 0.05).</p>
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<p>Ratio of tumor fraction damaged by agent to total tumor fraction affected (i.e., either damaged or killed) for cisplatin (<b>A</b>), doxorubicin (<b>B</b>), and etoposide (<b>C</b>). Results obtained from simulating multiple injections are shown by the triangles. Results from a single injection are shown by the squares. The color bar on the right shows the initial drug concentrations.</p>
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11 pages, 2149 KiB  
Article
Constructing a Clinical Patient Similarity Network of Gastric Cancer
by Rukui Zhang, Zhaorui Liu, Chaoyu Zhu, Hui Cai, Kai Yin, Fan Zhong and Lei Liu
Bioengineering 2024, 11(8), 808; https://doi.org/10.3390/bioengineering11080808 - 9 Aug 2024
Viewed by 207
Abstract
Objectives: Clinical molecular genetic testing and molecular imaging dramatically increase the quantity of clinical data. Combined with the extensive application of electronic health records, a medical data ecosystem is forming, which calls for big-data-based medicine models. We tried to use big data analytics [...] Read more.
Objectives: Clinical molecular genetic testing and molecular imaging dramatically increase the quantity of clinical data. Combined with the extensive application of electronic health records, a medical data ecosystem is forming, which calls for big-data-based medicine models. We tried to use big data analytics to search for similar patients in a cancer cohort, showing how to apply artificial intelligence (AI) algorithms to clinical data processing to obtain clinically significant results, with the ultimate goal of improving healthcare management. Methods: In order to overcome the weaknesses of most data processing algorithms that rely on expert labeling and annotation, we uniformly adopted one-hot encoding for all types of clinical data, calculating the Euclidean distance to measure patient similarity and subgrouping via an unsupervised learning model. Overall survival (OS) was investigated to assess the clinical validity and clinical relevance of the model. Results: We took gastric cancers (GCs) as an example to build a high-dimensional clinical patient similarity network (cPSN). When performing the survival analysis, we found that Cluster_2 had the longest survival rates, while Cluster_5 had the worst prognosis among all the subgroups. As patients in the same subgroup share some clinical characteristics, the clinical feature analysis found that Cluster_2 harbored more lower distal GCs than upper proximal GCs, shedding light on the debates. Conclusion: Overall, we constructed a cancer-specific cPSN with excellent interpretability and clinical significance, which would recapitulate patient similarity in the real-world. The constructed cPSN model is scalable, generalizable, and performs well for various data types. Full article
(This article belongs to the Special Issue Mathematical and Computational Modeling of Cancer Progression)
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<p>Three-dimensional <span class="html-italic">t</span>-SNE showing patient distribution in the constructed PSN. Colors show different subgroups identified in patient similarity analysis. Values in axes represent relative distance in the dimension.</p>
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<p>Clinical characteristics of each cluster derived from the constructed cPSN. The colors show the frequency of each categorical state of the variable. All 37 variables are shown in each cluster. ※ indicates specific features of Cluster_2 compared to other clusters.</p>
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<p>Kaplan–Meier survival analysis for OS by (<b>A</b>) subgroups, (<b>B</b>) patient age, (<b>C</b>) cancer differentiation, and (<b>D</b>) tumor stage. The five subgroups represent the patients classified into 5 clusters based on patient similarity calculation. Patient age is classified into quartiles. <span class="html-italic">p</span>-value shows statistical significance based on log-rank analysis.</p>
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13 pages, 2431 KiB  
Article
Enhancing Forensic Diagnostics: Structured Reporting of Post-Mortem CT versus Autopsy for Laryngohyoid Complex Fractures in Strangulation
by Andreas M. Bucher, Adrian Koppold, Mattias Kettner, Sarah Kölzer, Julia Dietz, Eric Frodl, Alexey Surov, Daniel Pinto dos Santos, Thomas J. Vogl, Marcel A. Verhoff, Martin Beeres, Constantin Lux and Sara Heinbuch
Bioengineering 2024, 11(8), 807; https://doi.org/10.3390/bioengineering11080807 - 9 Aug 2024
Viewed by 210
Abstract
Background: The purpose of this study was to establish a standardized structured workflow to compare findings from high-resolution, optimized reconstructions from post-mortem computed tomography (pmCT) with autopsy results in the detection of fractures of the laryngohyoid complex in strangulation victims. Method: Forty-two strangulation [...] Read more.
Background: The purpose of this study was to establish a standardized structured workflow to compare findings from high-resolution, optimized reconstructions from post-mortem computed tomography (pmCT) with autopsy results in the detection of fractures of the laryngohyoid complex in strangulation victims. Method: Forty-two strangulation cases were selected, and pmCT scans of the laryngohyoid complex were obtained. Both pmCT scans and autopsy reports were analyzed using a structured template and compared using Cohen’s kappa coefficient (κ) and the McNemar test. The study also compared the prevalence of ossa sesamoidea and non-fusion of the major and minor horns of the hyoid bone between both diagnostic methods. Results: The detection of fractures showed a very good correlation between autopsy and pmCT results (κ = 0.905), with the McNemar test showing no statistically significant difference between the two methods. PmCT identified 28 sesamoid bones, 45 non-fusions of the major horns, and 47 non-fusions of the minor horns of the hyoid bone, compared to four, six, and zero, respectively, identified by autopsy (p < 0.0001). Conclusions: Autopsy and pmCT findings correlate well and can be used in a complementary manner. PmCT is superior to autopsy in identifying dislocations and detecting anatomical variations in the laryngohyoid complex, which can lead to misinterpretations during autopsy. Therefore, we do not advocate replacing autopsy with pmCT but propose using a structured workflow, including our standardized reporting template, for evaluating lesions in the laryngohyoid complex. Full article
(This article belongs to the Section Biosignal Processing)
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<p>Flowchart of the study cohort.</p>
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<p>Non-dislocated fracture of the thyroid cartilage. The non-dislocated fracture is indicated by an arrowhead.</p>
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<p>Post-mortem CT of the larynx after reconstruction, where two fractures are visible (in the corpus and the cornu superius). The two fractures are indicated by arrowheads.</p>
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<p>Axial CT section on the height of the thyroid cartilage. The cartilage in this sample is not calcified. Non-calcified structures posed a limitation in our study, since non-displaced fractures in these samples are not readily visualized.</p>
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<p>Anatomic regions compared via autopsy and pmCT post-mortem. The number of fractures identified on pmCT is shown in parentheses. Non-OA publishing license: Adapted with permission from Shutterstock, Copyright 2017 (Standard License), Copyright Owner’s Name: Achiichiii, <a href="https://www.shutterstock.com/license" target="_blank">https://www.shutterstock.com/license</a>, accessed on 25 June 2024.</p>
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<p>Accuracy in detection of fractures, showing (from left to right) true negative (<span class="html-italic">n</span> = 247), false positive (<span class="html-italic">n</span> = 2), false negative (<span class="html-italic">n</span> = 4), and true positive (<span class="html-italic">n</span> = 33) findings for both CT and autopsy. This representation assumes autopsy findings to be the gold standard; the number of true negatives is represented by the bar on the far left and true positives on the far right. There were very few false positives (<span class="html-italic">n</span> = 2) and false negatives (<span class="html-italic">n</span> = 4). (The X-axis represents the findings from the autopsy: 0 = No Fracture, 1 = Fracture).</p>
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16 pages, 926 KiB  
Article
Adaptive Detection in Real-Time Gait Analysis through the Dynamic Gait Event Identifier
by Yifan Liu, Xing Liu, Qianhui Zhu, Yuan Chen, Yifei Yang, Haoyu Xie, Yichen Wang and Xingjun Wang
Bioengineering 2024, 11(8), 806; https://doi.org/10.3390/bioengineering11080806 - 8 Aug 2024
Viewed by 274
Abstract
The Dynamic Gait Event Identifier (DGEI) introduces a pioneering approach for real-time gait event detection that seamlessly aligns with the needs of embedded system design and optimization. DGEI creates a new standard for gait analysis by combining software and hardware co-design with real-time [...] Read more.
The Dynamic Gait Event Identifier (DGEI) introduces a pioneering approach for real-time gait event detection that seamlessly aligns with the needs of embedded system design and optimization. DGEI creates a new standard for gait analysis by combining software and hardware co-design with real-time data analysis, using a combination of first-order difference functions and sliding window techniques. The method is specifically designed to accurately separate and analyze key gait events such as heel strike (HS), toe-off (TO), walking start (WS), and walking pause (WP) from a continuous stream of inertial measurement unit (IMU) signals. The core innovation of DGEI is the application of its dynamic feature extraction strategies, including first-order differential integration with positive/negative windows, weighted sleep time analysis, and adaptive thresholding, which together improve its accuracy in gait segmentation. The experimental results show that the accuracy rate of HS event detection is 97.82%, and the accuracy rate of TO event detection is 99.03%, which is suitable for embedded systems. Validation on a comprehensive dataset of 1550 gait instances shows that DGEI achieves near-perfect alignment with human annotations, with a difference of less than one frame in pulse onset times in 99.2% of the cases. Full article
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<p>Schematic diagram of the principle of DGEI algorithm. The DGEI algorithm is able to identify and analyze various gait datasets, including standing, walking, fast start and stop, turning and mixed walking, among others.</p>
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<p>A detailed view of the gait analysis facilitated by the Dynamic Gait Event Identifier (DGEI).</p>
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<p>Advance identification of gait cycle peak points. The red dashed line represents the peak of the “pulse data” curve and the green represents the “DGEI” curve. The purple double-headed arrows, labeled <math display="inline"><semantics> <mrow> <mo>Δ</mo> <mi>t</mi> </mrow> </semantics></math>, indicate the number of frames predicted in advance.</p>
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<p>Comprehensive visualization of hyperparameter optimization results for the DGEI methodology: The top row (<b>a</b>,<b>c</b>,<b>e</b>) presents the optimization scenarios for the ‘sleeptime’ hyperparameter. The bottom row (<b>b</b>,<b>d</b>,<b>f</b>) illustrates the optimization outcomes for the ‘bar’ hyperparameter.</p>
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<p>The 3D coupling of sensitivity and MCC with two hyperparameters.</p>
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<p>The error distribution between the time frame of the matching event and the ground truth is compared with the normal distribution.</p>
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16 pages, 4028 KiB  
Article
Synthesizing High b-Value Diffusion-Weighted Imaging of Gastric Cancer Using an Improved Vision Transformer CycleGAN
by Can Hu, Congchao Bian, Ning Cao, Han Zhou and Bin Guo
Bioengineering 2024, 11(8), 805; https://doi.org/10.3390/bioengineering11080805 - 8 Aug 2024
Viewed by 319
Abstract
Background: Diffusion-weighted imaging (DWI), a pivotal component of multiparametric magnetic resonance imaging (mpMRI), plays a pivotal role in the detection, diagnosis, and evaluation of gastric cancer. Despite its potential, DWI is often marred by substantial anatomical distortions and sensitivity artifacts, which can hinder [...] Read more.
Background: Diffusion-weighted imaging (DWI), a pivotal component of multiparametric magnetic resonance imaging (mpMRI), plays a pivotal role in the detection, diagnosis, and evaluation of gastric cancer. Despite its potential, DWI is often marred by substantial anatomical distortions and sensitivity artifacts, which can hinder its practical utility. Presently, enhancing DWI’s image quality necessitates reliance on cutting-edge hardware and extended scanning durations. The development of a rapid technique that optimally balances shortened acquisition time with improved image quality would have substantial clinical relevance. Objectives: This study aims to construct and evaluate the unsupervised learning framework called attention dual contrast vision transformer cyclegan (ADCVCGAN) for enhancing image quality and reducing scanning time in gastric DWI. Methods: The ADCVCGAN framework, proposed in this study, employs high b-value DWI (b = 1200 s/mm2) as a reference for generating synthetic b-value DWI (s-DWI) from acquired lower b-value DWI (a-DWI, b = 800 s/mm2). Specifically, ADCVCGAN incorporates an attention mechanism CBAM module into the CycleGAN generator to enhance feature extraction from the input a-DWI in both the channel and spatial dimensions. Subsequently, a vision transformer module, based on the U-net framework, is introduced to refine detailed features, aiming to produce s-DWI with image quality comparable to that of b-DWI. Finally, images from the source domain are added as negative samples to the discriminator, encouraging the discriminator to steer the generator towards synthesizing images distant from the source domain in the latent space, with the goal of generating more realistic s-DWI. The image quality of the s-DWI is quantitatively assessed using metrics such as the peak signal-to-noise ratio (PSNR), structural similarity index (SSIM), feature similarity index (FSIM), mean squared error (MSE), weighted peak signal-to-noise ratio (WPSNR), and weighted mean squared error (WMSE). Subjective evaluations of different DWI images were conducted using the Wilcoxon signed-rank test. The reproducibility and consistency of b-ADC and s-ADC, calculated from b-DWI and s-DWI, respectively, were assessed using the intraclass correlation coefficient (ICC). A statistical significance level of p < 0.05 was considered. Results: The s-DWI generated by the unsupervised learning framework ADCVCGAN scored significantly higher than a-DWI in quantitative metrics such as PSNR, SSIM, FSIM, MSE, WPSNR, and WMSE, with statistical significance (p < 0.001). This performance is comparable to the optimal level achieved by the latest synthetic algorithms. Subjective scores for lesion visibility, image anatomical details, image distortion, and overall image quality were significantly higher for s-DWI and b-DWI compared to a-DWI (p < 0.001). At the same time, there was no significant difference between the scores of s-DWI and b-DWI (p > 0.05). The consistency of b-ADC and s-ADC readings was comparable among different readers (ICC: b-ADC 0.87–0.90; s-ADC 0.88–0.89, respectively). The repeatability of b-ADC and s-ADC readings by the same reader was also comparable (Reader1 ICC: b-ADC 0.85–0.86, s-ADC 0.85–0.93; Reader2 ICC: b-ADC 0.86–0.87, s-ADC 0.89–0.92, respectively). Conclusions: ADCVCGAN shows excellent promise in generating gastric cancer DWI images. It effectively reduces scanning time, improves image quality, and ensures the authenticity of s-DWI images and their s-ADC values, thus providing a basis for assisting clinical decision making. Full article
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<p>Presents the overall learning flowchart consisting of five steps. In Step 1, all patients underwent mp-MRI using b-values of 50, 800, and 1200 <math display="inline"><semantics> <msup> <mrow> <mi mathvariant="normal">s</mi> <mo>/</mo> <mi>mm</mi> </mrow> <mn>2</mn> </msup> </semantics></math>. For Step 2, model training was conducted with b = 800 <math display="inline"><semantics> <msup> <mrow> <mi mathvariant="normal">s</mi> <mo>/</mo> <mi>mm</mi> </mrow> <mn>2</mn> </msup> </semantics></math> as the input data from the training group, and b = 1200 <math display="inline"><semantics> <msup> <mrow> <mi mathvariant="normal">s</mi> <mo>/</mo> <mi>mm</mi> </mrow> <mn>2</mn> </msup> </semantics></math> as the target data. In Step 3, gastric cancer images were synthesized using the model inputs of b = 800 <math display="inline"><semantics> <msup> <mrow> <mi mathvariant="normal">s</mi> <mo>/</mo> <mi>mm</mi> </mrow> <mn>2</mn> </msup> </semantics></math> from the test group. Step 4 involved assessing the quality of the synthesized gastric cancer images through metrics such as the peak signal-to-noise ratio, structural similarity, feature similarity, mean square error, and subjective reading score by diagnosticians. Finally, Step 5 focused on analyzing the ADC consistency and repeatability of the synthetic gastric cancer images.</p>
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<p>Patient infographic with different datasets. This includes number of patients and gender.</p>
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<p>Schematic of the original CycleGAN model. <span class="html-italic">G</span> and <span class="html-italic">F</span> stand for generators, <math display="inline"><semantics> <msub> <mi>D</mi> <mi>x</mi> </msub> </semantics></math> and <math display="inline"><semantics> <msub> <mi>D</mi> <mi>y</mi> </msub> </semantics></math> stand for discriminators, <math display="inline"><semantics> <msub> <mi>G</mi> <mrow> <mo>(</mo> <mi>x</mi> <mo>)</mo> </mrow> </msub> </semantics></math> stands for the image of <span class="html-italic">x</span> generated by generator <span class="html-italic">G</span>, <math display="inline"><semantics> <msub> <mi>F</mi> <mrow> <mo>(</mo> <mi>y</mi> <mo>)</mo> </mrow> </msub> </semantics></math> stands for the image of <span class="html-italic">y</span> generated by generator <span class="html-italic">F</span>, <math display="inline"><semantics> <msub> <mi>G</mi> <mrow> <mo>(</mo> <mi>F</mi> <mo>(</mo> <mi>y</mi> <mo>)</mo> <mo>)</mo> </mrow> </msub> </semantics></math> stands for the image of <math display="inline"><semantics> <msub> <mi>F</mi> <mrow> <mo>(</mo> <mi>y</mi> <mo>)</mo> </mrow> </msub> </semantics></math> generated by generator <span class="html-italic">G</span>, and <math display="inline"><semantics> <msub> <mi>F</mi> <mrow> <mo>(</mo> <mi>G</mi> <mo>(</mo> <mi>x</mi> <mo>)</mo> <mo>)</mo> </mrow> </msub> </semantics></math> stands for the image of <math display="inline"><semantics> <msub> <mi>G</mi> <mrow> <mo>(</mo> <mi>x</mi> <mo>)</mo> </mrow> </msub> </semantics></math> generated by generator <span class="html-italic">F</span>.</p>
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<p>ADCVCGAN model generator section.The coding path of U-net extracts features from the input through four layers of convolution and downsampling, and passes the extracted features from each layer to the corresponding layer of the decoding path through skip connections. In the encoding path of U-net, the preprocessing layer converts the image into a tensor with dimensions (<span class="html-italic"><math display="inline"><semantics> <msub> <mi>w</mi> <mn>0</mn> </msub> </semantics></math>,<math display="inline"><semantics> <msub> <mi>h</mi> <mn>0</mn> </msub> </semantics></math>,<math display="inline"><semantics> <msub> <mi>f</mi> <mn>0</mn> </msub> </semantics></math></span>), and the preprocessed tensor halves the width <math display="inline"><semantics> <msub> <mi>w</mi> <mn>0</mn> </msub> </semantics></math> and the height <math display="inline"><semantics> <msub> <mi>h</mi> <mn>0</mn> </msub> </semantics></math> in each downsampled block while the feature dimension <math display="inline"><semantics> <msub> <mi>f</mi> <mn>0</mn> </msub> </semantics></math> is doubled.</p>
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<p>ViT module in ADCVCGAN.ViT is composed primarily of a stack of transformer encoder blocks. To construct an input to the stack, the ViT first flattens an encoded image along the spatial dimensions to form a sequence of tokens. The token sequence has length <span class="html-italic">w</span> × <span class="html-italic">h</span>, and each token in the sequence is a vector of length <span class="html-italic">f</span>. It then concatenates each token with its two-dimensional Fourier positional embedding of dimension <math display="inline"><semantics> <msub> <mi>f</mi> <mi>p</mi> </msub> </semantics></math> and linearly maps the result to have dimension <math display="inline"><semantics> <msub> <mi>f</mi> <mi>v</mi> </msub> </semantics></math>. To improve the Transformer convergence, we adopt the rezero regularization scheme and introduce a trainable scaling parameter <math display="inline"><semantics> <mi>α</mi> </semantics></math> that modulates the magnitudes of the nontrivial branches of the residual blocks. The output from the transformer stack is linearly projected back to have dimension <span class="html-italic">f</span> and unflattened to have width <span class="html-italic">w</span> and <span class="html-italic">h</span>. In this study, we use 12 transform encoder blocks.</p>
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<p>The structure of dual contrast [<a href="#B30-bioengineering-11-00805" class="html-bibr">30</a>]. The introduction of images from the source domain as negative samples compels the discriminator to steer the generator towards synthesizing images that diverge from the source domain within the latent space. Here, <math display="inline"><semantics> <msup> <mi>x</mi> <mo>′</mo> </msup> </semantics></math> and <math display="inline"><semantics> <msup> <mi>y</mi> <mo>′</mo> </msup> </semantics></math> represent randomly selected negative samples from the source image.</p>
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<p>DWI images of patients with gastric cancer. The figure shows the lesion range indicated by the red solid line, the signal inside the stomach indicated by the blue arrow, and the lymph node indicated by the green arrow. Patient A, male, 74 years old, subcardia-gastric body lesser curvature-gastric angle occupancy, infiltrating ulcer type. Patient B, male, 64 years old, occupancy of the gastric antrum, infiltrating ulcer type. Patient C, male, 66 years old, cardia-gastric lesser curvature occupancy, infiltrating ulcer type. Patient D, female, 72 years old, cardia to the lesser curvature of the gastric body occupation, infiltrating ulcer type. Patient E, male, 57 years old, gastric angle-sinus occupation, infiltrating ulcerative type. Patient F, male, 72 years old, lateral to the lesser curvature of the gastric body, infiltrating ulcer type.</p>
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<p>Violin plots of the quantitative metric distributions of the DWI.</p>
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<p>ADC images of patients with gastric cancer.</p>
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18 pages, 4956 KiB  
Article
An Exosome-Laden Hydrogel Wound Dressing That Can Be Point-of-Need Manufactured in Austere and Operational Environments
by E. Cate Wisdom, Andrew Lamont, Hannah Martinez, Michael Rockovich, Woojin Lee, Kristin H. Gilchrist, Vincent B. Ho and George J. Klarmann
Bioengineering 2024, 11(8), 804; https://doi.org/10.3390/bioengineering11080804 - 8 Aug 2024
Viewed by 397
Abstract
Skin wounds often form scar tissue during healing. Early intervention with tissue-engineered materials and cell therapies may promote scar-free healing. Exosomes and extracellular vesicles (EV) secreted by mesenchymal stromal cells (MSC) are believed to have high regenerative capacity. EV bioactivity is preserved after [...] Read more.
Skin wounds often form scar tissue during healing. Early intervention with tissue-engineered materials and cell therapies may promote scar-free healing. Exosomes and extracellular vesicles (EV) secreted by mesenchymal stromal cells (MSC) are believed to have high regenerative capacity. EV bioactivity is preserved after lyophilization and storage to enable use in remote and typically resource-constrained environments. We developed a bioprinted bandage containing reconstituted EVs that can be fabricated at the point-of-need. An alginate/carboxymethyl cellulose (CMC) biomaterial ink was prepared, and printability and mechanical properties were assessed with rheology and compression testing. Three-dimensional printed constructs were evaluated for Young’s modulus relative to infill density and crosslinking to yield material with stiffness suitable for use as a wound dressing. We purified EVs from human MSC-conditioned media and characterized them with nanoparticle tracking analysis and mass spectroscopy, which gave a peak size of 118 nm and identification of known EV proteins. Fluorescently labeled EVs were mixed to form bio-ink and bioprinted to characterize EV release. EV bandages were bioprinted on both a commercial laboratory bioprinter and a custom ruggedized 3D printer with bioprinting capabilities, and lyophilized EVs, biomaterial ink, and thermoplastic filament were deployed to an austere Arctic environment and bioprinted. This work demonstrates that EVs can be bioprinted with an alginate/CMC hydrogel and released over time when in contact with a skin-like substitute. The technology is suitable for operational medical applications, notably in resource-limited locations, including large-scale natural disasters, humanitarian crises, and combat zones. Full article
(This article belongs to the Section Biomedical Engineering and Biomaterials)
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<p>Isolation and characterization of EVs from MSC-conditioned media. (<b>A</b>) Schematic of EV isolation using size exclusion chromatography followed by lyophilization and characterization using mass spectrometry, NTA, and TEM (<b>B</b>). NTA of EVs collected showed a particle size peak of 118 nm with a concentration of 6.67 × 10<sup>9</sup> +/− 1.69 × 10<sup>7</sup> EVs/mL. Fresh EVs (<b>C</b>) and EVs following lyophilization (<b>D</b>) were imaged with TEM. Red arrows are pointing to the fresh (<b>C</b>) and lyophilized EVs (<b>D</b>) imaged with TEM.</p>
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<p>Rheology of alginate/CMC dressing biomaterial ink. A 0.05–100% shear strain sweep was performed at 23 °C on a parallel plate rheometer with a 0.5 mm gap and 1 Hz frequency (<b>A</b>). Storage modulus, G′ (black squares) and loss modulus, G″ (black triangles) and plotted. The storage modulus value was independent of shear strain up to approximately 1%, and G′ is greater than G″ indicating the biomaterial ink is a viscoelastic solid. (<b>B</b>) Viscosity study where biomaterial ink was loaded on a parallel plate rheometer with a 0.5 mm gap, 1 Hz frequency, and a ramp logarithmic program for shear rate was used from 0.005 to 200 s<sup>−1</sup>. The shear rate is plotted versus shear stress at 10 °C (blue triangles), 23 °C (black triangles), and 37 °C (red triangles). Increasing temperature decreased the viscosity. The biomaterial ink is non-Newtonian and shear thinning at each temperature. (<b>C</b>) Biomaterial ink yield stress determination at 23 °C. Samples were loaded on a parallel plate rheometer with a 0.5 mm gap. Shear stress was varied from 1 to 300 Pa using a ramp linear program. The yield stress was calculated using rheometer software.</p>
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<p>Print fidelity of alginate/CMC biomaterial ink at two different infill percentages before and after crosslinking with CaCl<sub>2</sub>. The bio-ink was 3D printed into a 20 × 20 × 3 mm object using a commercial bioprinter (BioX, Cellink). Print parameters were 6 mm/sec and up to 100 kPa pressure using a 22-gauge conical tip (<b>top row</b>). Infill was either 20% or 10%. Following printing, the prints were incubated in CaCl<sub>2</sub> for 60 min to crosslink the alginate component (<b>bottom row</b>).</p>
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<p>Printed Alginate/CMC hydrogel dressings with varying crosslinking times. Hydrogel dressings were printed with 20% infill and crosslinked in CaCl<sub>2</sub> for 5, 15, or 60 min.</p>
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<p>Mechanical testing of the printed bandage dressing squares. (<b>A</b>) Linear portion of example stress–strain curves for samples with 20% infill crosslinked for 5 min, R = 0.99 (Black Diamonds), 15 min, R = 0.99 (Grey Squares) or 60 min, R = 0.99 (Black Circles). The data were fit to linear regression, and the slope of the curve fit is Young’s modulus. (<b>B</b>) Maximum force at 10% strain and Young’s modulus of printed alginate/CMC hydrogel dressings after 5, 15, and 60 min of crosslinking in CaCl<sub>2</sub>.</p>
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<p>Bioprinted alginate/CMC dressing with reconstituted, red fluorescently labeled EVs. The bioactive dressing was bioprinted with 20% infill and imaged before crosslinking (<b>A</b>) and after crosslinking (<b>B</b>). A confocal microscopy z-stack, tile scan at 20X magnification visualized as a 3D projection of the red-boxed region of the alginate/CMC/EV dressing (inset) (<b>C</b>). The labeled EVs are distributed throughout the hydrogel dressing material.</p>
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<p>Transfer of EVs from dressing bio-ink to collagen blocks. (<b>A</b>) A 3D-printed collagen block was used to simulate skin to test the transfer of EVs from the printed dressing to the skin. The alginate/CMC dressing was printed using 20% infill, crosslinked, and cut to 10 mm × 10 mm × 3 mm. It was placed on top of a similar-sized collagen block and incubated at 37 °C in a 6-well plate with 1 mL of PBS to keep the collagen hydrated. (<b>B</b>) Positive control: a solution of fluorescently labeled EVs pipetted on top of the collagen and left to absorb. The collagen block was removed at 24 h and imaged for the appearance of labeled EVs transferred from the dressings that were crosslinked for (<b>C</b>) 10 min or (<b>D</b>) 60 min. Microscopy images taken at 20X magnification.</p>
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<p>Three-dimensional printing and bioprinting of a wound dressing in a laboratory environment using a ruggedized 3D printer. The alginate/CMC dressing was bioprinted onto an FFF 3D printed PLA backing and crosslinked with CaCl<sub>2</sub> solution for 10 min.</p>
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<p>(<b>A</b>) CAD rendering and (<b>B</b>) bioprinted bandage with alginate/CMC EV-laden bio-ink dressing.</p>
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<p>Ruggedized 3D printer for point-of-need manufacturing of a bioactive wound dressing. The 3D printer contained three printheads. A fused filament fabrication (FFF) printhead was used to print the PLA thermoplastic backing. Two pneumatic printheads were used to print the alginate/EV bioactive bio-ink and a commercially available adhesive.</p>
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13 pages, 3189 KiB  
Article
Enhancing Fermentation Process Monitoring through Data-Driven Modeling and Synthetic Time Series Generation
by Hyun J. Kwon, Joseph H. Shiu, Celina K. Yamakawa and Elmer C. Rivera
Bioengineering 2024, 11(8), 803; https://doi.org/10.3390/bioengineering11080803 - 8 Aug 2024
Viewed by 322
Abstract
Soft sensors based on deep learning regression models are promising approaches to predict real-time fermentation process quality measurements. However, experimental datasets are generally sparse and may contain outliers or corrupted data. This leads to insufficient model prediction performance. Therefore, datasets with a fully [...] Read more.
Soft sensors based on deep learning regression models are promising approaches to predict real-time fermentation process quality measurements. However, experimental datasets are generally sparse and may contain outliers or corrupted data. This leads to insufficient model prediction performance. Therefore, datasets with a fully distributed solution space are required that enable effective exploration during model training. In this study, the robustness and predictive capability of the underlying model of a soft sensor was improved by generating synthetic datasets for training. The monitoring of intensified ethanol fermentation is used as a case study. Variational autoencoders were employed to create synthetic datasets, which were then combined with original datasets (experimental) to train neural network regression models. These models were tested on original versus augmented datasets to assess prediction improvements. Using the augmented datasets, the soft sensor predictive capability improved by 34%, and variability was reduced by 82%, based on R2 scores. The proposed method offers significant time and cost savings for dataset generation for the deep learning modeling of ethanol fermentation and can be easily adapted to other fermentation processes. This work contributes to the advancement of soft sensor technology, providing practical solutions for enhancing reliability and robustness in large-scale production. Full article
(This article belongs to the Special Issue ML and AI for Augmented Biosensing Applications)
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<p>Convolutional variational autoencoder architecture. The deep learning network starts with the input data and then successively feeds into five convolutional layers. The output from the final convolutional layer is fed to the fully connected (dense) layers, which constructs the latent space. To reconstruct the contact maps, we use five successive de-convolutional layers, mirroring the forward convolutional layers.</p>
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<p>Time series for inputs: pH, redox (mV), capacitance (pF/cm), temperature (°C), and output: concentration of ethanol (g/L). The top row shows the time series of the original data from 11 experiments, the middle row shows the 100 VAE-generated datasets, and the bottom row shows the 100 GAN-generated datasets. The data shows the temporal progression of input and output data alongside the data spread.</p>
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<p>VAE training loss metrics for 250 epochs.</p>
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<p>Histograms of features (inputs), pH, redox (mV), capacitance (pF/cm), temperature (°C), and output: concentration of ethanol (g/L) for data sources (original, VAE, and GAN).</p>
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<p>t-SNE plots for (<b>a</b>) the VAE and original data, and (<b>b</b>) for the GAN and original data. The original data are marked with red triangles and the generated data are marked with blue hexagons for the VAE and green hexagons for the GAN.</p>
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<p>Histogram for R<sup>2</sup> for (<b>a</b>) Original model, (<b>c</b>) Augmented10 model, and (<b>e</b>) Augmented100 model. Histogram for RMSE for (<b>b</b>) Original model, (<b>d</b>) Augmented10 model, and (<b>f</b>) Augmented100 model.</p>
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<p>Predicted vs. original ethanol concentration for Anomalous data (represented by experiments 9) and Baseline data (represented by Exp. 2). The orange line represents the predicted ethanol concentration, while the blue markers represent the originally measured data, both with normalized values. The column of panels on the left shows the prediction results for Anomalous data using the (<b>a</b>) Original model, (<b>c</b>) Augmented10 model, and (<b>e</b>) Augmented100 model. The column of panels on the right shows the prediction results for Baseline data using the (<b>b</b>) Original model, (<b>d</b>) Augmented10 model, and (<b>f</b>) Augmented100 model.</p>
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13 pages, 2880 KiB  
Article
Wavelet Coherence Analysis of Post-Stroke Intermuscular Coupling Modulated by Myoelectric-Controlled Interfaces
by Xinyi He, Wenbo Sun, Rong Song and Weiling Xu
Bioengineering 2024, 11(8), 802; https://doi.org/10.3390/bioengineering11080802 - 8 Aug 2024
Viewed by 302
Abstract
Intermuscular coupling reflects the corticospinal interaction associated with the control of muscles. Nevertheless, the deterioration of intermuscular coupling caused by stroke has not received much attention. The purpose of this study was to investigate the effect of myoelectric-controlled interface (MCI) dimensionality on the [...] Read more.
Intermuscular coupling reflects the corticospinal interaction associated with the control of muscles. Nevertheless, the deterioration of intermuscular coupling caused by stroke has not received much attention. The purpose of this study was to investigate the effect of myoelectric-controlled interface (MCI) dimensionality on the intermuscular coupling after stroke. In total, ten age-matched controls and eight stroke patients were recruited and executed elbow tracking tasks within 1D or 2D MCI. Movement performance was quantified using the root mean square error (RMSE). Wavelet coherence was used to analyze the intermuscular coupling in alpha band (8–12 Hz) and beta band (15–35 Hz). The results found that smaller RMSE of antagonist muscles was observed in both groups within 2D MCI compared to 1D MCI. The alpha-band wavelet coherence was significantly lower in the patients compared to the controls during elbow extension. Furthermore, a decreased alpha-band and beta-band wavelet coherence was observed in the controls and stroke patients, as the dimensionality of MCI increased. These results may suggest that stroke-related neural impairments deteriorate the motor performance and intermuscular coordination pattern, and, further, that MCI holds promise as a novel effective tool for rehabilitation through the direct modulation of muscle activation pattern. Full article
(This article belongs to the Section Biosignal Processing)
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<p>Example scenes of four types of visual feedback. One-dimensional MCI, in which the red cursor represents the target cursor, and the green cursor represents the manipulable cursor moving along the dashed line during flexion (<b>a</b>) and extension (<b>b</b>); two-dimensional MCI, in which the green cursor moves in the 2D coordinate system during flexion (<b>c</b>) and extension (<b>d</b>).</p>
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<p>Typical muscle activation, EMG signals of the biceps and triceps, and the binary wavelet coherence in the alpha and beta bands recorded during an 1D elbow flexion task. Control: a healthy subject; stroke: a stroke patient. Target activation: 15% MVC; Std: the standard deviation calculated from target activation and muscle activation.</p>
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<p>Averaging binary wavelet coherence AFWC between biceps and triceps in the alpha band and beta band between the controls (the red line) and the patients (the blue line). (<b>a</b>) During the elbow flexion task within both 1D and 2D MCI; (<b>b</b>) during the elbow extension task within both 1D and 2D MCI.</p>
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<p>Bar plots of mean RMSE in each group within 1D and 2D MCI during the elbow flexion and extension. The number sign (#) indicates significant difference between controls and stroke patients. The error bar shows standard error.</p>
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<p>Bar plots of mean RMSE of antagonist muscles mapped to <span class="html-italic">x</span>-axis or <span class="html-italic">y</span>-axis, respectively, in each condition during the elbow flexion (<b>a</b>) and extension (<b>b</b>). The error bar shows standard error.</p>
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<p>Bar plots of mean alpha-band and beta-band binary wavelet coherence in both groups within 1D and 2D MCI during the elbow flexion (<b>a</b>) and extension (<b>b</b>). The asterisk (*) indicates significant pairwise difference between 1D and 2D MCI, and the number sign (#) indicates significant difference between controls and stroke patients. The error bar shows standard error.</p>
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27 pages, 5324 KiB  
Article
Near-Infrared Forearm Vascular Width Calculation Using Radius Estimation of Tangent Circle
by Qianru Ji, Haoting Liu, Zhen Tian, Song Wang, Qing Li and Dewei Yi
Bioengineering 2024, 11(8), 801; https://doi.org/10.3390/bioengineering11080801 - 7 Aug 2024
Viewed by 310
Abstract
In response to the analysis of the functional status of forearm blood vessels, this paper fully considers the orientation of the vascular skeleton and the geometric characteristics of blood vessels and proposes a blood vessel width calculation algorithm based on the radius estimation [...] Read more.
In response to the analysis of the functional status of forearm blood vessels, this paper fully considers the orientation of the vascular skeleton and the geometric characteristics of blood vessels and proposes a blood vessel width calculation algorithm based on the radius estimation of the tangent circle (RETC) in forearm near-infrared images. First, the initial infrared image obtained by the infrared camera is preprocessed by image cropping, contrast stretching, denoising, enhancement, and initial segmentation. Second, the Zhang–Suen refinement algorithm is used to extract the vascular skeleton. Third, the Canny edge detection method is used to perform vascular edge detection. Finally, a RETC algorithm is developed to calculate the vessel width. This paper evaluates the accuracy of the proposed RETC algorithm, and experimental results show that the mean absolute error between the vessel width obtained by our algorithm and the reference vessel width is as low as 0.36, with a variance of only 0.10, which can be significantly reduced compared to traditional calculation measurements. Full article
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<p>Near-infrared forearm venous angiography of different subjects. (<b>a</b>) Male with low body fat. (<b>b</b>) Female with high body fat. (<b>c</b>) Male with high body fat.</p>
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<p>Algorithm flowchart of near-infrared blood vessel width computation. The processes of the proposed algorithm include image preprocessing, skeleton extraction, edge detection, and vascular width calculation.</p>
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<p>Preprocessing computational flowchart.</p>
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<p>Pixel position map. (<b>a</b>) Diagram of the eight neighboring pixels around the center pixel P1. (<b>b</b>) Diagram example of P1 and its eight neighbors.</p>
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<p>Venous vascular diagram.</p>
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<p>Experiment equipment and data. (<b>a</b>) The entire collection device. (<b>b</b>) Near-infrared camera and forearm placement table. (<b>c</b>) Application case of the proposed device. (<b>d</b>) Photo example of subject experiment. (<b>e</b>) Image data samples.</p>
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<p>Experimental results of image enhancement algorithms. (<b>a</b>) The results of HE. (<b>b</b>) The results of AHE. (<b>c</b>) The results of SSR. (<b>d</b>) The results of RCAE and CLAHE.</p>
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<p>Experimental results of different vascular skeleton extraction algorithms. (<b>a</b>) Hand-labeled vascular skeleton. (<b>b</b>) The result of the morphological refinement algorithm based on Hit and Miss. (<b>c</b>) The result of the skeleton extraction algorithm based on judgment templates. (<b>d</b>) The result of the Hilditch refinement algorithm. (<b>e</b>) The result of the Zhang–Suen refinement algorithm.</p>
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<p>Experiment results of different blood vessel edge detection methods. (<b>a</b>) Result of the Roberts operator. (<b>b</b>) Result of the Sobel operator. (<b>c</b>) Result of the Prewitt operator. (<b>d</b>) Result of the Canny operator.</p>
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<p>Measurement method for reference vessel width. The black lines in figures represent the ruler tool.</p>
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<p>Inscribed circle image samples. The red graphs represent the inscribed circles that intersect with the edges of blood vessels obtained using the RETC algorithm.</p>
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<p>Line chart comparison of results from different blood vessel width calculation methods.</p>
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27 pages, 16898 KiB  
Article
αvβ3 Integrin and Folate-Targeted pH-Sensitive Liposomes with Dual Ligand Modification for Metastatic Breast Cancer Treatment
by Prashant Pandey, Dilip Kumar Arya, Payal Deepak, Daoud Ali, Saud Alarifi, Saurabh Srivastava, Afsaneh Lavasanifar and Paruvathanahalli Siddalingam Rajinikanth
Bioengineering 2024, 11(8), 800; https://doi.org/10.3390/bioengineering11080800 - 7 Aug 2024
Viewed by 346
Abstract
The advent of pH-sensitive liposomes (pHLips) has opened new opportunities for the improved and targeted delivery of antitumor drugs as well as gene therapeutics. Comprising fusogenic dioleylphosphatidylethanolamine (DOPE) and cholesteryl hemisuccinate (CHEMS), these nanosystems harness the acidification in the tumor microenvironment and endosomes [...] Read more.
The advent of pH-sensitive liposomes (pHLips) has opened new opportunities for the improved and targeted delivery of antitumor drugs as well as gene therapeutics. Comprising fusogenic dioleylphosphatidylethanolamine (DOPE) and cholesteryl hemisuccinate (CHEMS), these nanosystems harness the acidification in the tumor microenvironment and endosomes to deliver drugs effectively. pH-responsive liposomes that are internalized through endocytosis encounter mildly acidic pH in the endosomes and thereafter fuse or destabilize the endosomal membrane, leading to subsequent cargo release into the cytoplasm. The extracellular tumor matrix also presents a slightly acidic environment that can lead to the enhanced drug release and improved targeting capabilities of the nano-delivery system. Recent studies have shown that folic acid (FA) and iRGD-coated nanocarriers, including pH-sensitive liposomes, can preferentially accumulate and deliver drugs to breast tumors that overexpress folate receptors and αvβ3 and αvβ5 integrins. This study focuses on the development and characterization of 5-Fluorouracil (5-FU)-loaded FA and iRGD surface-modified pHLips (FA-iRGD-5-FU-pHLips). The novelty of this research lies in the dual targeting mechanism utilizing FA and iRGD peptides, combined with the pH-sensitive properties of the liposomes, to enhance selective targeting and uptake by cancer cells and effective drug release in the acidic tumor environment. The prepared liposomes were small, with an average diameter of 152 ± 3.27 nm, uniform, and unilamellar, demonstrating efficient 5-FU encapsulation (93.1 ± 2.58%). Despite surface functionalization, the liposomes maintained their pH sensitivity and a neutral zeta potential, which also conferred stability and reduced aggregation. Effective pH responsiveness was demonstrated by the observation of enhanced drug release at pH 5.5 compared to physiological pH 7.4. (84.47% versus 46.41% release at pH 5.5 versus pH 7.4, respectively, in 72 h). The formulations exhibited stability for six months and were stable when subjected to simulated biological settings. Blood compatibility and cytotoxicity studies on MDA-MB-231 and SK-BR3 breast cancer cell lines revealed an enhanced cytotoxicity of the liposomal formulation that was modified with FA and iRGD compared to free 5-FU and minimal hemolysis. Collectively, these findings support the potential of FA and iRGD surface-camouflaged, pH-sensitive liposomes as a promising drug delivery strategy for breast cancer treatment. Full article
(This article belongs to the Special Issue Natural Peptides/Proteins and Their Applications in Bioengineering)
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<p>Panels (<b>A</b>–<b>C</b>) depict linear correlation plots illustrating the relationship between predicted and actual values for particle size, % entrapment efficiency, and % pH sensitivity, respectively. Panels (<b>D</b>–<b>F</b>) display surface response 3D plots demonstrating the impact of the molar ratio of E80:DOPE and molar concentration of CHEMS on particle size, % entrapment efficiency, and % pH sensitivity, respectively. Panels (<b>G</b>–<b>I</b>) show surface response 3D plots illustrating the impact of the molar ratio of E80:DOPE and the amount of drug on particle size, % entrapment efficiency, and % pH sensitivity, respectively. Panels (<b>J</b>–<b>L</b>) display surface response 3D plots showcasing the effect of the molar concentration of CHEMS and the amount of drug on particle size, % entrapment efficiency, and % pH sensitivity, respectively.</p>
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<p>Pareto chart analysis of the Box-Behnken design showing the standardized effect of independent variables and their interaction on (<b>A</b>) PS, (<b>B</b>) % EE, and (<b>C</b>) % pH sensitivity. The vertical break black lines represent the threshold of significance (<span class="html-italic">p</span> = 0.05).</p>
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<p>Desirability graph (<b>A</b>) and overlay plot (<b>B</b>) of optimized formulation.</p>
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<p>2D contour plots representing the impact of selected independent variables on dependent variables like particle size (<b>A</b>–<b>C</b>), % entrapment efficiency (<b>D</b>–<b>F</b>), and % pH sensitivity (<b>G</b>–<b>I</b>).</p>
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<p>Proposed reaction scheme for DSPE-PEG<sub>2000</sub>-FA conjugate (<b>A</b>), FT-IR spectra of DSPE-PEG<sub>2000</sub>-FA conjugate (<b>B</b>), and <sup>1</sup>H NMR spectra of DSPE-PEG<sub>2000</sub>-FA conjugate (<b>C</b>).</p>
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<p>Proposed reaction scheme for DSPE-PEG<sub>2000</sub>-iRGD (<b>A</b>); <sup>1</sup>H NMR spectra of DSPE-PEG<sub>2000</sub>-iRGD conjugate (<b>B</b>); and FT-IR spectra of DSPE-PEG<sub>2000</sub>-iRGD (<b>C</b>).</p>
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<p>Particle size intensity distribution (<b>A</b>) and zeta potential (<b>B</b>) of 5-FU-pHLip and FA-iRGD-5-FU-pHLip, respectively. TEM (<b>C</b>), AFM (<b>D</b>), and (<b>E</b>) FT-IR micrographs of FA-iRGD-5-FU-pHLip.</p>
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<p>Physico-chemical characterization of the developed pH-sensitive liposomes (<b>A</b>), possible scenario of the pH sensitivity of FA-iRGD-5-FU-pHLip at pH 7.4 and 5.5 (<b>B</b>), in-vitro % pH sensitivity of free 5-FU drug and FA-iRGD-5-FU-pHLip at pH 7.4 and 5.5 (<b>C</b>), pH-induced liposomal aggregation assays of 5-FU-pHLip and FA-iRGD-5-FU-pHLip formulations in different pH media (<b>D</b>,<b>E</b>).</p>
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<p>In-vitro stability of liposomes under study in PBS (pH 7.4) and DMEM in terms of mean particle size (<b>A</b>,<b>B</b>) and zeta potential (<b>C</b>,<b>D</b>), respectively. Data are expressed by the mean (<span class="html-italic">n</span> = 3) ± SD.</p>
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<p>Serum stability assessment data of the developed FA-iRGD-5-FU-pHLip in terms of mean particle size and zeta potential.</p>
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<p>Storage stability data in terms of the mean particle size (<b>A</b>), zeta potential (<b>B</b>), and entrapment efficiency (<b>C</b>) up to 6 months: % hemolysis plots of plain 5-FU solutions and liposomal formulations at various 5-FU concentrations (<b>D</b>). Data are expressed by the mean (<span class="html-italic">n</span> = 3) ± SD. [One asterisk (*), three asterisks (***), and four asterisks (****) denote significant <span class="html-italic">p</span> values, i.e., &lt;0.05, &lt;0.001 and &lt;0.0001, respectively, and ns as non-significant].</p>
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<p>Wound healing assay (<b>A</b>,<b>B</b>); the % of wound closure plot (<b>C</b>); viable MDA-MB-231 and SK-BR3 cell percentages versus an empty liposome concentration equivalent to that used for drug-loaded liposomes in Figures (<b>F</b>,<b>G</b>) over the period of 72 h (<b>D</b>,<b>E</b>); viable MDA-MB-231 and SK-BR3 cell percentage versus concentrations of 5-FU in cells treated with free 5-FU, 5-FU-pHLip, and FA-iRGD-5-FU-pHLip over the period of 48 h (<b>F</b>,<b>G</b>) and 72 h (<b>H</b>,<b>I</b>), respectively. [One asterisk (*), two asterisks (**), and three asterisks (***) denote significant <span class="html-italic">p</span> values, i.e., &lt;0.05, &lt;0.01, and &lt;0.001, respectively, and ns as non-significant].</p>
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20 pages, 3931 KiB  
Article
Novel Hybrid Quantum Architecture-Based Lung Cancer Detection Using Chest Radiograph and Computerized Tomography Images
by Jason Elroy Martis, Sannidhan M S, Balasubramani R, A. M. Mutawa and M. Murugappan
Bioengineering 2024, 11(8), 799; https://doi.org/10.3390/bioengineering11080799 - 7 Aug 2024
Viewed by 308
Abstract
Lung cancer, the second most common type of cancer worldwide, presents significant health challenges. Detecting this disease early is essential for improving patient outcomes and simplifying treatment. In this study, we propose a hybrid framework that combines deep learning (DL) with quantum computing [...] Read more.
Lung cancer, the second most common type of cancer worldwide, presents significant health challenges. Detecting this disease early is essential for improving patient outcomes and simplifying treatment. In this study, we propose a hybrid framework that combines deep learning (DL) with quantum computing to enhance the accuracy of lung cancer detection using chest radiographs (CXR) and computerized tomography (CT) images. Our system utilizes pre-trained models for feature extraction and quantum circuits for classification, achieving state-of-the-art performance in various metrics. Not only does our system achieve an overall accuracy of 92.12%, it also excels in other crucial performance measures, such as sensitivity (94%), specificity (90%), F1-score (93%), and precision (92%). These results demonstrate that our hybrid approach can more accurately identify lung cancer signatures compared to traditional methods. Moreover, the incorporation of quantum computing enhances processing speed and scalability, making our system a promising tool for early lung cancer screening and diagnosis. By leveraging the strengths of quantum computing, our approach surpasses traditional methods in terms of speed, accuracy, and efficiency. This study highlights the potential of hybrid computational technologies to transform early cancer detection, paving the way for wider clinical applications and improved patient care outcomes. Full article
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<p>Proposed system’s architecture.</p>
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<p>Leveraging transfer learning for feature extraction from CT and CXR images.</p>
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<p>Visual analysis of different layers of TL framework.</p>
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<p>The architecture of the quantum variational circuit with five qubits.</p>
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<p>The QCNN architecture with quantum operations and measurements.</p>
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<p>Sample images from the adopted datasets. (<b>a</b>) Normal, (<b>b</b>) benign, (<b>c</b>) malignant.</p>
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<p>Training and loss accuracy for different epochs of the system.</p>
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<p>Performance evaluation of hybrid models using ROC curves.</p>
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<p>Performance evaluation of hybrid models using confusion matrices.</p>
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<p>Performance evaluation of hybrid models using confusion matrices.</p>
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12 pages, 10066 KiB  
Article
Primary Stability of Kyphoplasty in Incomplete Vertebral Body Burst Fractures in Osteoporosis: A Biomechanical Investigation
by Oliver Riesenbeck, Niklas Czarnowski, Michael Johannes Raschke, Simon Oeckenpöhler and René Hartensuer
Bioengineering 2024, 11(8), 798; https://doi.org/10.3390/bioengineering11080798 - 7 Aug 2024
Viewed by 265
Abstract
Background: The objective of our study was to biomechanically evaluate the use of kyphoplasty to stabilize post-traumatic segmental instability in incomplete burst fractures of the vertebrae. Methods: The study was performed on 14 osteoporotic spine postmortem samples (Th11–L3). First, acquisition of the native [...] Read more.
Background: The objective of our study was to biomechanically evaluate the use of kyphoplasty to stabilize post-traumatic segmental instability in incomplete burst fractures of the vertebrae. Methods: The study was performed on 14 osteoporotic spine postmortem samples (Th11–L3). First, acquisition of the native multisegmental kinematics in our robot-based spine tester with three-dimensional motion analysis was set as a baseline for each sample. Then, an incomplete burst fracture was generated in the vertebral body L1 with renewed kinematic testing. After subsequent kyphoplasty was performed on the fractured vertebral body, primary stability was examined again. Results: Initially, a significant increase in the range of motion after incomplete burst fracture generation in all three directions of motion (extension–flexion, lateral tilt, axial rotation) was detected as proof of post-traumatic instability. There were no significant changes to the native state in the adjacent segments. Radiologically, a significant loss of height in the fractured vertebral body was also shown. Traumatic instability was significantly reduced by kyphoplasty. However, native kinematics were not restored. Conclusions: Although post-traumatic segmental instability was significantly reduced by kyphoplasty in our in vitro model, native kinematics could not be reconstructed, and significant instability remained. Full article
(This article belongs to the Special Issue Spine Biomechanics)
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<p>Modified fracture creation by distance-controlled compression after osteotomy-like weakening of the upper endplate L1. Specimen before compression (<b>left</b>) and after fracture induction by axial compression (<b>right</b>).</p>
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<p>Hydraulic material testing machine used to create standardized incomplete burst fractures and obtain radiographs. At the <b>left</b>, the mounted motion capture marker (rigid bodies) and radiographic reference (arrow) are shown. At the <b>right</b> is a magnified lateral view of a mounted sample.</p>
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<p>Radiographs of the native sample (<b>a</b>), fractured specimen (<b>b</b>), balloon in position (<b>c</b>), inflated balloon (<b>d</b>), inserted cement (<b>e</b>), and after cement insertion using the anteroposterior technique (<b>f</b>).</p>
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<p>Mounted specimen in the robot-based spine tester combined with active optical motion tracking to record each single segmental kinematic behavior in a multisegmental setup: overview (<b>left</b>) and magnified view with rigid bodies and follower-load applications (<b>right</b>).</p>
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<p>Schematic presentation of height measurement via lateral radiographic projection: posterior (AB), anterior (CD), middle (EF), and posterior two-thirds (GH). I1 and I2 are perpendicular midline intersections for the construction of the points E and F [<a href="#B24-bioengineering-11-00798" class="html-bibr">24</a>].</p>
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<p>Boxplot of lateral vertebral body height in millimeters. Anterior (cd), middle (ef), and posterior (ab) values are presented by condition: intact, blue; fractured, yellow; reconstructed by kyphoplasty (kypho), red.</p>
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<p>Boxplot of kinematic median values of functional spinal unit Th12–L1 for axial rotation, extension–flexion, and lateral flexion. Intact values without (light blue) and with follower load (blue), fractured values with follower load (yellow), and values after kyphoplasty with follower load (red). Circle represents outliers and five-pointed asterisk represents extreme outliers.</p>
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<p>Boxplot of kinematic median values of functional spinal unit L1–L2 for axial rotation, extension–flexion, and lateral flexion. Intact values without (light blue) and with follower load (blue), values for fractures with follower load (yellow), and values after kyphoplasty with follower load (red). Circle represents outliers and five-pointed asterisk represents extreme outliers.</p>
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15 pages, 3549 KiB  
Article
Genetic and Modifiable Risk Factors for Postoperative Complications of Total Joint Arthroplasty: A Genome-Wide Association and Mendelian Randomization Study
by Sijia Guo, Jiping Zhang, Huiwu Li, Cheng-Kung Cheng and Jingwei Zhang
Bioengineering 2024, 11(8), 797; https://doi.org/10.3390/bioengineering11080797 - 7 Aug 2024
Viewed by 286
Abstract
Background: Total joint arthroplasty (TJA) is an orthopedic procedure commonly used to treat damaged joints. Despite the efficacy of TJA, postoperative complications, including aseptic prosthesis loosening and infections, are common. Moreover, the effects of individual genetic susceptibility and modifiable risk factors on [...] Read more.
Background: Total joint arthroplasty (TJA) is an orthopedic procedure commonly used to treat damaged joints. Despite the efficacy of TJA, postoperative complications, including aseptic prosthesis loosening and infections, are common. Moreover, the effects of individual genetic susceptibility and modifiable risk factors on these complications are unclear. This study analyzed these effects to enhance patient prognosis and postoperative management. Methods: We conducted an extensive genome-wide association study (GWAS) and Mendelian randomization (MR) study using UK Biobank data. The cohort included 2964 patients with mechanical complications post-TJA, 957 with periprosthetic joint infection (PJI), and a control group of 398,708 individuals. Genetic loci associated with postoperative complications were identified by a GWAS analysis, and the causal relationships of 11 modifiable risk factors with complications were assessed using MR. Results: The GWAS analysis identified nine loci associated with post-TJA complications. Two loci near the PPP1R3B and RBM26 genes were significantly linked to mechanical complications and PJI, respectively. The MR analysis demonstrated that body mass index was positively associated with the risk of mechanical complications (odds ratio [OR]: 1.42; p < 0.001). Higher educational attainment was associated with a decreased risk of mechanical complications (OR: 0.55; p < 0.001) and PJI (OR: 0.43; p = 0.001). Type 2 diabetes was suggestively associated with mechanical complications (OR, 1.18, p = 0.02), and hypertension was suggestively associated with PJI (OR, 1.41, p = 0.008). Other lifestyle factors, including smoking and alcohol consumption, were not causally related to postoperative complications. Conclusions: The genetic loci near PPP1R3B and RBM26 influenced the risk of post-TJA mechanical complications and infections, respectively. The effects of genetic and modifiable risk factors, including body mass index and educational attainment, underscore the need to perform personalized preoperative assessments and the postoperative management of surgical patients. These results indicate that integrating genetic screening and lifestyle interventions into patient care can improve the outcomes of TJA and patient quality of life. Full article
(This article belongs to the Special Issue Novel and Advanced Technologies for Orthopaedic Implant)
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<p>Overview of this study’s design.</p>
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<p>Manhattan plot of GWAS on mechanical complications after total joint arthroplasty. The red line and blue line represent genome-wide significance (<span class="html-italic">p</span> &lt; 5 × 10<sup>−8</sup>) and suggestive significance (<span class="html-italic">p</span> &lt; 1 × 10<sup>−6</sup>), respectively.</p>
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<p>Manhattan plot of GWAS analysis of periprosthetic joint infections after total joint arthroplasty. The red line and blue line represent genome-wide significance (<span class="html-italic">p</span> &lt; 5 × 10<sup>−8</sup>) and suggestive significance (<span class="html-italic">p</span> &lt; 1 × 10<sup>−6</sup>), respectively.</p>
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<p>Forest plot of Mendelian randomization estimates of the association of modifiable lifestyle factors with mechanical complications after total joint arthroplasty. MR, Mendelian randomization; OR, odds ratio; CI, confidence interval.</p>
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<p>Forest plot of Mendelian randomization estimates of the association of modifiable lifestyle factors with periprosthetic joint infections after total joint arthroplasty. MR, Mendelian randomization; OR, odds ratio; CI, confidence interval.</p>
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<p>Manhattan plot of the gene-based analysis of mechanical complications. The red line indicates genome-wide significance (<span class="html-italic">p</span> &lt; 2.63 × 10<sup>−6</sup>).</p>
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<p>Manhattan plot of the gene-based analysis of periprosthetic joint infections. The red line represents genome-wide significance (<span class="html-italic">p</span> &lt; 2.63 × 10<sup>−6</sup>).</p>
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17 pages, 5578 KiB  
Article
Interactive Cascaded Network for Prostate Cancer Segmentation from Multimodality MRI with Automated Quality Assessment
by Weixuan Kou, Cristian Rey, Harry Marshall and Bernard Chiu
Bioengineering 2024, 11(8), 796; https://doi.org/10.3390/bioengineering11080796 - 6 Aug 2024
Viewed by 322
Abstract
The accurate segmentation of prostate cancer (PCa) from multiparametric MRI is crucial in clinical practice for guiding biopsy and treatment planning. Existing automated methods often lack the necessary accuracy and robustness in localizing PCa, whereas interactive segmentation methods, although more accurate, require user [...] Read more.
The accurate segmentation of prostate cancer (PCa) from multiparametric MRI is crucial in clinical practice for guiding biopsy and treatment planning. Existing automated methods often lack the necessary accuracy and robustness in localizing PCa, whereas interactive segmentation methods, although more accurate, require user intervention on each input image, thereby limiting the cost-effectiveness of the segmentation workflow. Our innovative framework addresses the limitations of current methods by combining a coarse segmentation network, a rejection network, and an interactive deep network known as Segment Anything Model (SAM). The coarse segmentation network automatically generates initial segmentation results, which are evaluated by the rejection network to estimate their quality. Low-quality results are flagged for user interaction, with the user providing a region of interest (ROI) enclosing the lesions, whereas for high-quality results, ROIs were cropped from the automatic segmentation. Both manually and automatically defined ROIs are fed into SAM to produce the final fine segmentation. This approach significantly reduces the annotation burden and achieves substantial improvements by flagging approximately 20% of the images with the lowest quality scores for manual annotation. With only half of the images manually annotated, the final segmentation accuracy is statistically indistinguishable from that achieved using full manual annotation. Although this paper focuses on prostate lesion segmentation from multimodality MRI, the framework can be adapted to other medical image segmentation applications to improve segmentation efficiency while maintaining high accuracy standards. Full article
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<p>Examples of PCa segmentation results from U-Net [<a href="#B9-bioengineering-11-00796" class="html-bibr">9</a>]. The red and blue contours represent ground truth and algorithm segmentation, respectively. (<b>a</b>–<b>c</b>) show cases with false positives and false negatives generated by the automated segmentation method, and (<b>d</b>,<b>e</b>) show cases where the automated segmentation method demonstrates superior performance.</p>
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<p>The workflow of the proposed interactive cascaded network.</p>
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<p>The segmentation results of our method are compared qualitatively with those produced by two automatic segmentation methods in five example images. The red and blue contours represent ground truth and algorithm segmentation, respectively. Prostate (<b>a</b>–<b>c</b>) are from the Prostate158 dataset, and Prostate (<b>d</b>,<b>e</b>) are from the PROSTATEx2 dataset.</p>
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<p>The segmentation results of our method are compared qualitatively with those produced by two fully interactive segmentation methods in five example images. The red and blue contours represent ground truth and algorithm segmentation, respectively. Prostate (<b>a</b>–<b>c</b>) are from the Prostate158 dataset, and Prostate (<b>d</b>,<b>e</b>) are from the PROSTATEx2 dataset.</p>
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<p>The influence of the burdens of human intervention on the model performance in the Prostate158 dataset. The rejection ratio quantifies the burden of human intervention. (<b>a</b>) shows the correlation between the threshold, <span class="html-italic">t</span>, and the rejection ratio in our study; (<b>b</b>) shows the effect of t on the overall model performance.</p>
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18 pages, 4509 KiB  
Article
Biomechanical Comparisons between One- and Two-Compartment Devices for Reconstructing Vertebrae by Kyphoplasty
by Oliver Riesenbeck, Niklas Czarnowski, Michael Johannes Raschke, Simon Oeckenpöhler and René Hartensuer
Bioengineering 2024, 11(8), 795; https://doi.org/10.3390/bioengineering11080795 - 5 Aug 2024
Viewed by 369
Abstract
Background: This biomechanical in vitro study compared two kyphoplasty devices for the extent of height reconstruction, load-bearing capacity, cement volume, and adjacent fracture under cyclic loading. Methods: Multisegmental (T11–L3) specimens were mounted into a testing machine and subjected to compression, creating an incomplete [...] Read more.
Background: This biomechanical in vitro study compared two kyphoplasty devices for the extent of height reconstruction, load-bearing capacity, cement volume, and adjacent fracture under cyclic loading. Methods: Multisegmental (T11–L3) specimens were mounted into a testing machine and subjected to compression, creating an incomplete burst fracture of L1. Kyphoplasty was performed using a one- or two-compartment device. Then, the testing machine was used for a cyclic loading test of load-bearing capacity to compare the two groups for the amount of applied load until failure and subsequent adjacent fracture. Results: Vertebral body height reconstruction was effective for both groups but not statistically significantly different. After cyclic loading, refracture of vertebrae that had undergone kyphoplasty was not observed in any specimen, but fractures were observed in adjacent vertebrae. The differences between the numbers of cycles and of loads were not statistically significant. An increase in cement volume was strongly correlated with increased risks of adjacent fractures. Conclusion: The two-compartment device was not substantially superior to the one-compartment device. The use of higher cement volume correlated with the occurrence of adjacent fractures. Full article
(This article belongs to the Special Issue Spine Biomechanics)
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<p>Embedding the specimens and creating incomplete burst fractures. § Motion trackers were not used in this work. ↕ The height of the intact vertebra L1 was measured by a ruler. * Radiographic reference ball; # incomplete burst fracture in L1.</p>
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<p>Lateral radiographic views of a one-compartment device with (<b>A</b>) inflated balloons and (<b>B</b>) cement fill, and a two-compartment device with (<b>C</b>) inflated balloons and (<b>D</b>) cement fill. The catheters were inserted through the cannulas, which are indicated by asterisks (*).</p>
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<p>Schematic drawing of catheters and balloons. (<b>A</b>) One-compartment device (Joline S9403); (<b>B</b>) two-compartment device (Joline S9420).</p>
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<p>Lateral radiographs taken of (<b>A</b>) initial specimens before compression; (<b>B</b>) after compression; (<b>C</b>) after catheter insertion; (<b>D</b>) after balloon inflation; (<b>E</b>) and after kyphoplasty. The asterisk (*) in frame (<b>A</b>) of the one-compartment group refers to the radiographic reference ball. An arrow in both groups (<b>C</b>) points to the cannula.</p>
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<p>Schematics based on lateral vertebral radiographic projections showing vertebral height measurements (mm) by referring to the referencing ball, as shown in <a href="#bioengineering-11-00795-f004" class="html-fig">Figure 4</a>. (<b>A</b>) after compression and fracture and before catheter insertion and (<b>B</b>) after cement insertion. Three of the four measurements were taken in places as per McKiernan et al. [<a href="#B28-bioengineering-11-00795" class="html-bibr">28</a>]: (a) posterior; (b) one-third distance from posterior to anterior; and (d) anterior. The additional location (c), centered between anterior and posterior, was added here.</p>
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<p>Test of load-bearing capacity by cyclic loading in a stepwise cyclic compression protocol. (<b>A</b>) At the beginning of a step (a; e; i), a baseline load of 0.015 kN was applied. Then, through 1.5 s, the load was applied to reach the minimum load for that step (b; f; j). Cyclic loading for that step was applied (b to c; f to g). Each complete 250 s step (the blue areas) consisted of 500 cycles (2 Hz frequency) for 52.5 N per step (slope, 0.21 N/s). With cyclic loading load of a step (c; g), the load was held constant (c to d; g to h) for the taking of a radiograph to examine for failure. When failure occurred, loading was discontinued, and cumulative load was recorded at the moment of failure. If fracture or compression was not observed, then cyclic loading was resumed by reducing to the minimum force of 0.015 kN (d to e; h to i), and a new step began. Cyclic loading was resumed (f; j) by applying the maximum force that had been reached in the previous step (c; g), and the next step began if necessary. (<b>B</b>) The test, as depicted in A, was designed for 20 steps. In the event that failure had not occurred by the end of 20 steps, testing was continued by adding additional steps by increasing cyclic loading to 70 N per step for an increased slope of 0.28 N/s.</p>
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<p>Lateral radiographic images upon kyphoplasty of L1 (<b>A</b>,<b>B</b>) and after adjacent fracture of T12 (<b>C</b>,<b>D</b>) resulting from the cyclic loading test of load-bearing capacity. The asterisk (*) in (<b>A</b>) refers to the radiographic reference ball. The arrows in (<b>C</b>,<b>D</b>) point to the fractured T12.</p>
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<p>Percentage decreases in vertebra L1 height after compression calculated from the values shown in <a href="#bioengineering-11-00795-t001" class="html-table">Table 1</a>. Heights were measured at the four places shown in <a href="#bioengineering-11-00795-f005" class="html-fig">Figure 5</a>. (a) One-compartment group; (b) two-compartment group. Numbers refer to specimens; <span class="html-italic">p</span>-values were calculated by using the Mann–Whitney U-Test.</p>
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<p>Percentage increases in vertebra L1 height from after compression to after kyphoplasty. Heights were measured at the four places shown in <a href="#bioengineering-11-00795-f005" class="html-fig">Figure 5</a>. (a) One-compartment group; (b) two-compartment group. Numbers refer to specimens; <span class="html-italic">p</span>-values were calculated by using the Mann–Whitney U-Test.</p>
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<p>(<b>A</b>) applied loads and (<b>B</b>) numbers of applied cycles until failure (defined by the radiological appearance of fractures adjacent to vertebra L1 (<a href="#bioengineering-11-00795-f007" class="html-fig">Figure 7</a>) and/or by a compression depth of 7 cm underneath the starting position. Numbers refer to specimens; <span class="html-italic">p</span>-values were calculated by using the Mann–Whitney U-Test.</p>
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<p>(<b>A</b>) correlations between applied load at failure and (<b>B</b>) between the number of applied cycles at failure with cement volume. Failure was defined by the radiological appearance of fractures adjacent to vertebra L1 (<a href="#bioengineering-11-00795-f007" class="html-fig">Figure 7</a>) and/or by a compression depth of 7 cm underneath the starting position. Numbers refer to specimens. The Spearman correlation coefficients were −0.8 (<span class="html-italic">p</span> = 0.001) for both (<b>A</b>,<b>B</b>).</p>
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11 pages, 4821 KiB  
Article
Formation and Long-Term Culture of hiPSC-Derived Sensory Nerve Organoids Using Microfluidic Devices
by Takuma Ogawa, Souichi Yamada, Shuetsu Fukushi, Yuya Imai, Jiro Kawada, Kazutaka Ikeda, Seii Ohka and Shohei Kaneda
Bioengineering 2024, 11(8), 794; https://doi.org/10.3390/bioengineering11080794 - 5 Aug 2024
Viewed by 447
Abstract
Although methods for generating human induced pluripotent stem cell (hiPSC)-derived motor nerve organoids are well established, those for sensory nerve organoids are not. Therefore, this study investigated the feasibility of generating sensory nerve organoids composed of hiPSC-derived sensory neurons using a microfluidic approach. [...] Read more.
Although methods for generating human induced pluripotent stem cell (hiPSC)-derived motor nerve organoids are well established, those for sensory nerve organoids are not. Therefore, this study investigated the feasibility of generating sensory nerve organoids composed of hiPSC-derived sensory neurons using a microfluidic approach. Notably, sensory neuronal axons from neurospheres containing 100,000 cells were unidirectionally elongated to form sensory nerve organoids over 6 mm long axon bundles within 14 days using I-shaped microchannels in microfluidic devices composed of polydimethylsiloxane (PDMS) chips and glass substrates. Additionally, the organoids were successfully cultured for more than 60 days by exchanging the culture medium. The percentage of nuclei located in the distal part of the axon bundles (the region 3−6 mm from the entrance of the microchannel) compared to the total number of cells in the neurosphere was 0.005% for live cells and 0.008% for dead cells. Molecular characterization confirmed the presence of the sensory neuron marker ISL LIM homeobox 1 (ISL1) and the capsaicin receptor transient receptor potential vanilloid 1 (TRPV1). Moreover, capsaicin stimulation activated TRPV1 in organoids, as evidenced by significant calcium ion influx. Conclusively, this study demonstrated the feasibility of long-term organoid culture and the potential applications of sensory nerve organoids in bioengineered nociceptive sensors. Full article
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<p>Microfluidic device for generating sensory nerve organoids. (<b>a</b>) Device design. (<b>b</b>) Photograph of the fabricated device. Scale bar: 5 mm.</p>
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<p>The formation of sensory nerve organoids. (<b>a</b>) Axon elongation in the microchannel. The 1–4 mm regions from the entrance of the microchannel are magnified. Scale bar: 1 mm. (<b>b</b>) The length of the leading axons in the microchannels. The vertical axis value of 6 mm indicates an axon length of 6 mm or more. The error bars indicate ± the standard error of the mean (SEM), <span class="html-italic">n</span> = 12.</p>
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<p>Representative images of a series of long-term cultured sensory nerve organoids. Axon bundle diameters at 3 mm from the entrance of the microchannel are indicated by two arrows. The 1–4 mm regions from the entrance of the microchannel are magnified. Scale bar: 1 mm.</p>
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<p>Analysis of live cell contamination in the axon bundles. (<b>a</b>) Visualization of the nuclei using fluorescence probes. The 1–6 mm regions from the entrance of the microchannel are magnified. Scale bar: 1 mm. (<b>b</b>) The number of nuclei derived from live and dead cells in each region of the axon bundles. The position indicates the distance from the entrance of the microchannels. Organoids cultured for 19 days were used. The error bars indicate ± SEM, <span class="html-italic">n</span> = 6.</p>
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<p>Characterization of neurospheres and axon bundles using fluorescent immunostaining. (<b>a</b>,<b>b</b>) TUJ1 as a neuron marker and (<b>a</b>) ISL1 as a sensory neuron marker. An organoid cultured for 39 days was used. (<b>b</b>) TRPV1 as a nociceptor marker. An organoid cultured for 28 days was used. White-colored scale bars: 500 μm. Gray-colored scale bars in close-up panels for axon bundles: 100 μm.</p>
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<p>Response of sensory nerve organoids to capsaicin stimulation. (<b>a</b>) Fluo 4-AM intensity indicating intracellular calcium ion influx following capsaicin (upper panel) and DMSO (control; lower panel) treatments. Capsaicin solution (100 μM) or DMSO was poured into reservoir of device at 0 s. Scale bars: 1 mm. (<b>b</b>) Time course of Fluo 4-AM fluorescent intensity in neurospheres and axon bundles. Timing for pouring 100 μM capsaicin solution or DMSO at 0 s is indicated by an arrow. ROIs for intensity measurements are dotted ellipses for neurospheres and dotted rectangles for axon bundles in (<b>a</b>). Representative data of organoids cultured for 32 days were used.</p>
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17 pages, 1289 KiB  
Review
Muscle Synergy Analysis as a Tool for Assessing the Effectiveness of Gait Rehabilitation Therapies: A Methodological Review and Perspective
by Daniele Borzelli, Cristiano De Marchis, Angelica Quercia, Paolo De Pasquale, Antonino Casile, Angelo Quartarone, Rocco Salvatore Calabrò and Andrea d’Avella
Bioengineering 2024, 11(8), 793; https://doi.org/10.3390/bioengineering11080793 - 5 Aug 2024
Viewed by 497
Abstract
According to the modular hypothesis for the control of movement, muscles are recruited in synergies, which capture muscle coordination in space, time, or both. In the last two decades, muscle synergy analysis has become a well-established framework in the motor control field and [...] Read more.
According to the modular hypothesis for the control of movement, muscles are recruited in synergies, which capture muscle coordination in space, time, or both. In the last two decades, muscle synergy analysis has become a well-established framework in the motor control field and for the characterization of motor impairments in neurological patients. Altered modular control during a locomotion task has been often proposed as a potential quantitative metric for characterizing pathological conditions. Therefore, the purpose of this systematic review is to analyze the recent literature that used a muscle synergy analysis of neurological patients’ locomotion as an indicator of motor rehabilitation therapy effectiveness, encompassing the key methodological elements to date. Searches for the relevant literature were made in Web of Science, PubMed, and Scopus. Most of the 15 full-text articles which were retrieved and included in this review identified an effect of the rehabilitation intervention on muscle synergies. However, the used experimental and methodological approaches varied across studies. Despite the scarcity of studies that investigated the effect of rehabilitation on muscle synergies, this review supports the utility of muscle synergies as a marker of the effectiveness of rehabilitative therapy and highlights the challenges and open issues that future works need to address to introduce the muscle synergies in the clinical practice and decisional process. Full article
(This article belongs to the Special Issue Bioengineering of the Motor System)
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<p>PRISMA flowchart for study inclusion/exclusion.</p>
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<p>Percentage of the selected studies in which the activity of a muscle is collected.</p>
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16 pages, 6140 KiB  
Article
An Interpretable System for Screening the Severity Level of Retinopathy in Premature Infants Using Deep Learning
by Wenhan Yang, Hao Zhou, Yun Zhang, Limei Sun, Li Huang, Songshan Li, Xiaoling Luo, Yili Jin, Wei Sun, Wenjia Yan, Jing Li, Jianxiang Deng, Zhi Xie, Yao He and Xiaoyan Ding
Bioengineering 2024, 11(8), 792; https://doi.org/10.3390/bioengineering11080792 - 5 Aug 2024
Viewed by 288
Abstract
Accurate evaluation of retinopathy of prematurity (ROP) severity is vital for screening and proper treatment. Current deep-learning-based automated AI systems for assessing ROP severity do not follow clinical guidelines and are opaque. The aim of this study is to develop an interpretable AI [...] Read more.
Accurate evaluation of retinopathy of prematurity (ROP) severity is vital for screening and proper treatment. Current deep-learning-based automated AI systems for assessing ROP severity do not follow clinical guidelines and are opaque. The aim of this study is to develop an interpretable AI system by mimicking the clinical screening process to determine ROP severity level. A total of 6100 RetCam Ⅲ wide-field digital retinal images were collected from Guangdong Women and Children Hospital at Panyu (PY) and Zhongshan Ophthalmic Center (ZOC). A total of 3330 images of 520 pediatric patients from PY were annotated to train an object detection model to detect lesion type and location. A total of 2770 images of 81 pediatric patients from ZOC were annotated for stage, zone, and the presence of plus disease. Integrating stage, zone, and the presence of plus disease according to clinical guidelines yields ROP severity such that an interpretable AI system was developed to provide the stage from the lesion type, the zone from the lesion location, and the presence of plus disease from a plus disease classification model. The ROP severity was calculated accordingly and compared with the assessment of a human expert. Our method achieved an area under the curve (AUC) of 0.95 (95% confidence interval [CI] 0.90–0.98) in assessing the severity level of ROP. Compared with clinical doctors, our method achieved the highest F1 score value of 0.76 in assessing the severity level of ROP. In conclusion, we developed an interpretable AI system for assessing the severity level of ROP that shows significant potential for use in clinical practice for ROP severity level screening. Full article
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<p>The workflow for automatic assessment of the severity level of retinopathy of prematurity: (<b>A</b>) represents the data collection, model training and prediction, and lesion stitching, and finally predicts the stage and zone results of ROP; (<b>B</b>) represents data collection, predicting plus disease and obtaining the final result of whether each eye has plus disease or not. The severity grade is ultimately inferred based on the stage, zone, and whether it is a plus lesion in ROP according to clinical guidelines. Z I represents zone I; Z II S II+ represents zone II and stage II with plus disease.</p>
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<p>The flowchart of pre-training [<a href="#B53-bioengineering-11-00792" class="html-bibr">53</a>]. Two retinal images were sent to a feature extraction module based on ResNet50 and an image registration prediction module, resulting in a registered image. The model weights generated during this process were used for downstream task training.</p>
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<p>The performance of three training strategies for lesion detection: (<b>A</b>) represents the AUC metric for the training set; (<b>B</b>) represents the AUC metric for the validation dataset.</p>
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<p>The flowchart of domain adaptation. The target domain ZOC images and their cropped patches are transformed into the flowchart of domain adaptation based on CycleGAN. The blue parts in the image represent the processing module or results for the entire fundus image in the ZOC, while the red parts represent the processing module or results for the cropped patches from ZOC. We utilize the source domain PY vessel segmentation task model and the feature style alignment module to constrain the model. The final output will be images with a style similar to the source domain PY data.</p>
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<p>The confusion matrices of our method and clinical doctors in assessing the stage of ROP tasks: (<b>A</b>) represents our system; (<b>B</b>) represents clinical doctor A; (<b>C</b>) represents clinical doctor B; (<b>D</b>) represents clinical doctor X; (<b>E</b>) represents clinical doctor Y; (<b>F</b>) represents clinical doctor Z. The horizontal axis of the confusion matrix ranges from 0 to 4, representing the predicted stages from stage 0 (indicating no ROP lesions) to stage Ⅳ.</p>
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<p>Performance of various methods in assessing the stage of ROP tasks; (<b>A</b>) represents the comparison between various methods on the kappa index in assessing the stage of ROP; (<b>B</b>) represents the comparison between various methods on the accuracy index in assessing the stage of ROP. Method 1 represents our method; method 2 represents random initialization plus domain adaptation; method 3 represents using ImageNet plus domain adaptation; method 4 represents using homologous pretrain; method 5 represents using random initialization; method 6 represents using ImageNet.</p>
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<p>The confusion matrices of our method and clinical doctors in assessing the zone of ROP tasks: (<b>A</b>) represents our system; (<b>B</b>) represents clinical doctor A; (<b>C</b>) represents clinical doctor B; (<b>D</b>) represents clinical doctor X; (<b>E</b>) represents clinical doctor Y; (<b>F</b>) represents clinical doctor Z.</p>
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<p>Performance of various methods in assessing the zone of ROP tasks: (<b>A</b>) represents the comparison between various methods on the kappa index in assessing the zone of ROP; (<b>B</b>) represents the comparison between various methods on the accuracy index in assessing the zone of ROP.</p>
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<p>Performance in assessing the severity level of ROP tasks between our system and ophthalmologists.</p>
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<p>The performance of severity level of ROP between three methods which were adopted by domain adaptation: the red line represents method 1, which is our method; the blue line represents method 2, which is using domain adaptation with random initialization; the green line represents method 3, which is using domain adaptation with ImageNet; the yellow line represents method 4, which is using homologous pretrain; the black line represents method 5, which is using random initialization; the purple line represents method 6, which is using ImageNet.</p>
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<p>The visualization of our method. Box outlines in (<b>A</b>–<b>D</b>) indicate the type and sites of lesions: (<b>A</b>) stage I: demarcation line; (<b>B</b>) stage II: ridge; (<b>C</b>) stage III: ridge with extra retinal fibrovascular involvement; (<b>D</b>) stage IV: subtotal retinal detachment. The red circle in the middle represents zone one; the region between the purple and red circles represents zone two; and the area between the green and purple circles represents zone three. The yellow rectangle and red rectangle in the figure represent the area predicted by the model for the lesion and annotated by the doctor, respectively. The yellow letters and red letters represent the lesion type predicted and annotated by the doctor, respectively.</p>
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<p>The visualization of our method. Box outlines in (<b>A</b>–<b>D</b>) indicate the type and sites of lesions: (<b>A</b>) stage I: demarcation line; (<b>B</b>) stage II: ridge; (<b>C</b>) stage III: ridge with extra retinal fibrovascular involvement; (<b>D</b>) stage IV: subtotal retinal detachment. The red circle in the middle represents zone one; the region between the purple and red circles represents zone two; and the area between the green and purple circles represents zone three. The yellow rectangle and red rectangle in the figure represent the area predicted by the model for the lesion and annotated by the doctor, respectively. The yellow letters and red letters represent the lesion type predicted and annotated by the doctor, respectively.</p>
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16 pages, 1311 KiB  
Article
Hybrid Predictive Machine Learning Model for the Prediction of Immunodominant Peptides of Respiratory Syncytial Virus
by Syed Nisar Hussain Bukhari and Kingsley A. Ogudo
Bioengineering 2024, 11(8), 791; https://doi.org/10.3390/bioengineering11080791 - 5 Aug 2024
Viewed by 505
Abstract
Respiratory syncytial virus (RSV) is a common respiratory pathogen that infects the human lungs and respiratory tract, often causing symptoms similar to the common cold. Vaccination is the most effective strategy for managing viral outbreaks. Currently, extensive efforts are focused on developing a [...] Read more.
Respiratory syncytial virus (RSV) is a common respiratory pathogen that infects the human lungs and respiratory tract, often causing symptoms similar to the common cold. Vaccination is the most effective strategy for managing viral outbreaks. Currently, extensive efforts are focused on developing a vaccine for RSV. Traditional vaccine design typically involves using an attenuated form of the pathogen to elicit an immune response. In contrast, peptide-based vaccines (PBVs) aim to identify and chemically synthesize specific immunodominant peptides (IPs), known as T-cell epitopes (TCEs), to induce a targeted immune response. Despite their potential for enhancing vaccine safety and immunogenicity, PBVs have received comparatively less attention. Identifying IPs for PBV design through conventional wet-lab experiments is challenging, costly, and time-consuming. Machine learning (ML) techniques offer a promising alternative, accurately predicting TCEs and significantly reducing the time and cost of vaccine development. This study proposes the development and evaluation of eight hybrid ML predictive models created through the permutations and combinations of two classification methods, two feature weighting techniques, and two feature selection algorithms, all aimed at predicting the TCEs of RSV. The models were trained using the experimentally determined TCEs and non-TCE sequences acquired from the Bacterial and Viral Bioinformatics Resource Center (BV-BRC) repository. The hybrid model composed of the XGBoost (XGB) classifier, chi-squared (ChST) weighting technique, and backward search (BST) as the optimal feature selection algorithm (ChST−BST–XGB) was identified as the best model, achieving an accuracy, sensitivity, specificity, F1 score, AUC, precision, and MCC of 97.10%, 0.98, 0.97, 0.98, 0.99, 0.99, and 0.96, respectively. Additionally, K-fold cross-validation (KFCV) was performed to ensure the model’s reliability and an average accuracy of 97.21% was recorded for the ChST−BST–XGB model. The results indicate that the hybrid XGBoost model consistently outperforms other hybrid approaches. The epitopes predicted by the proposed model may serve as promising vaccine candidates for RSV, subject to in vitro and in vivo scientific assessments. This model can assist the scientific community in expediting the screening of active TCE candidates for RSV, ultimately saving time and resources in vaccine development. Full article
(This article belongs to the Special Issue Machine Learning Technology in Predictive Healthcare)
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<p>Structure of RSV.</p>
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<p>Proposed methodology.</p>
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<p>K-fold cross-validation technique.</p>
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<p>KFCV results of the hybrid model as depicted in <a href="#bioengineering-11-00791-f004" class="html-fig">Figure 4</a>; it is evident that the hybrid XGBoost model exhibits the most consistent accuracy results compared to the RF hybrid techniques. The results indicate that the proposed model stands out due to its comprehensive hybrid framework that combines multiple feature weighting, selection, and classification techniques, aiming to capture diverse peptide characteristics for improved accuracy. Unlike many existing tools relying on single models or limited feature engineering, the proposed approach leverages the strengths of different algorithms to mitigate potential biases. Moreover, the KFCV technique mitigates the risk of overfitting by dividing the dataset into K equal-sized folds. The model is trained on K-1 folds and tested on the remaining fold iteratively. This process provides a more reliable estimate of model performance on unseen data by exposing the model to different subsets of the data during training.</p>
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6 pages, 193 KiB  
Editorial
Machine Learning for Biomedical Applications
by Giuseppe Cesarelli, Alfonso Maria Ponsiglione, Mario Sansone, Francesco Amato, Leandro Donisi and Carlo Ricciardi
Bioengineering 2024, 11(8), 790; https://doi.org/10.3390/bioengineering11080790 - 5 Aug 2024
Viewed by 342
Abstract
Machine learning (ML) is a field of artificial intelligence that uses algorithms capable of extracting knowledge directly from data that could support decisions in multiple fields of engineering [...] Full article
(This article belongs to the Special Issue Machine Learning for Biomedical Applications)
11 pages, 4629 KiB  
Article
Compliance with Headgear Evaluated by Force- and Temperature-Sensitive Monitoring Device: A Case-Control Study
by Francesca Cremonini, Ariyan Karami Shabankare, Daniela Guiducci and Luca Lombardo
Bioengineering 2024, 11(8), 789; https://doi.org/10.3390/bioengineering11080789 - 5 Aug 2024
Viewed by 298
Abstract
The aim was to objectively assess compliance in patients prescribed headgear and evaluate the impact of monitoring awareness, treatment duration, gender, and age on compliance levels. A total of 22 patients with Class II malocclusion wore the headgear integrated with the force and [...] Read more.
The aim was to objectively assess compliance in patients prescribed headgear and evaluate the impact of monitoring awareness, treatment duration, gender, and age on compliance levels. A total of 22 patients with Class II malocclusion wore the headgear integrated with the force and temperature sensitive Smartgear monitoring system (Smartgear, Swissorthodontics AG, Cham, Switzerland). Patients were instructed to wear the headgear for 13 h daily over a 3-month period. Randomly, 11 patients were informed that they monitored and 11 were not informed. Data were organized using Microsoft Excel and analyzed using R for statistical estimates, graphs, and hypothesis testing. Smartgear recorded an average daily compliance of 6.7 h. No statistically significant differences were found in cooperation between study group and control group over the 3 months of treatment, regardless of gender and age. However, there was slight greater cooperation in the first month than in the other months, and patients ≤10 years of age had almost 2 h more cooperation than their older counterparts. Moreover, the informed group exhibited an average of 1.1 more hours of cooperation per day than the uninformed group, which may carry clinical significance. This cooperation primarily occurred at night and was found to be statistically significant. Compliance among young patients typically remained lower than the prescribed level, regardless of their gender and psychological maturity. Although an awareness of monitoring does not seem to improve compliance, implementing such systems could still offer dentists a valuable means of obtaining objective information about their patients’ adherence. Full article
(This article belongs to the Section Biomedical Engineering and Biomaterials)
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<p>Smartgear compliance monitoring device integrated in headgear.</p>
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<p>Example of a graph generated by the software.</p>
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<p>Compliance in study and control groups.</p>
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<p>Compliance trend during the 3 months of observation.</p>
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16 pages, 3954 KiB  
Review
Supercritical Fluids: An Innovative Strategy for Drug Development
by Hui Liu, Xiaoliu Liang, Yisheng Peng, Gang Liu and Hongwei Cheng
Bioengineering 2024, 11(8), 788; https://doi.org/10.3390/bioengineering11080788 - 4 Aug 2024
Viewed by 589
Abstract
Nanotechnology plays a pivotal role in the biomedical field, especially in the synthesis and regulation of drug particle size. Reducing drug particles to the micron or nanometer scale can enhance bioavailability. Supercritical fluid technology, as a green drug development strategy, is expected to [...] Read more.
Nanotechnology plays a pivotal role in the biomedical field, especially in the synthesis and regulation of drug particle size. Reducing drug particles to the micron or nanometer scale can enhance bioavailability. Supercritical fluid technology, as a green drug development strategy, is expected to resolve the challenges of thermal degradation, uneven particle size, and organic solvent residue faced by traditional methods such as milling and crystallization. This paper provides an insight into the application of super-stable homogeneous intermix formulating technology (SHIFT) and super-table pure-nanomedicine formulation technology (SPFT) developed based on supercritical fluids for drug dispersion and micronization. These technologies significantly enhance the solubility and permeability of hydrophobic drugs by controlling the particle size and morphology, and the modified drugs show excellent therapeutic efficacy in the treatment of hepatocellular carcinoma, pathological scarring, and corneal neovascularization, and their performance and efficacy are highlighted when administered through multiple routes of administration. Overall, supercritical fluids have opened a green and efficient pathway for clinical drug development, which is expected to reduce side effects and enhance therapeutic efficacy. Full article
(This article belongs to the Special Issue 10th Anniversary of Bioengineering: Perspectives in Bioengineering)
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<p>Schematic representation of a supercritical fluid technology for drug solubilization and nanonization. The red part represents the supercritical dispersion strategy and the blue part represents the supercritical nanosizing strategy.</p>
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<p>Drug dispersion assisted by super-stable homogeneous intermix formulating (SHIFT) technology. (<b>a</b>) The schematic illustration of SHIFT. (<b>b</b>) The photograph of free ICG and SHIFTs of newly prepared and stored after 30 days. (<b>c</b>) The fluorescence intensity of free ICG and SHIFTs. (<b>d</b>) The infrared thermal temperature of SHIFT, free ICG and lipiodol after laser irradiation. Reprinted with permission from Ref. [<a href="#B17-bioengineering-11-00788" class="html-bibr">17</a>]. With the development of radiotherapy technology and interventional medicine, transarterial radioembolization (TARE), as a branch of arterial embolization therapy, combines radioactive particles with embolizing agents to reach the focal site embolized by vascular interventions and produce radiation for therapeutic purposes [<a href="#B25-bioengineering-11-00788" class="html-bibr">25</a>,<a href="#B26-bioengineering-11-00788" class="html-bibr">26</a>]. Lipiodol as a labeling carrier combined with radionuclides for therapeutic drugs, such as 131I, 125I-lipiodol markers have been widely used in clinical treatment. The <sup>131</sup>I-iodine oil retained in the hepatic artery for internal irradiation of tumors has higher therapeutic efficacy and lower probability of postoperative complications compared with oral sodium iodide (<sup>131</sup>I) solution [<a href="#B27-bioengineering-11-00788" class="html-bibr">27</a>,<a href="#B28-bioengineering-11-00788" class="html-bibr">28</a>]. SHIFT technology can replace the traditional mixing method of heating and stirring to improve the stability of radionuclides in iodine oil to achieve the effect of long-lasting internal radiation therapy, and the imaging ability of radionuclides can also help the specificity of the embolization site. The universal application of SHIFT technology allows the loading of multiple nuclide warheads for therapeutic or monitoring functions, showing excellent application prospects.</p>
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<p>Drug crystallization by supercritical fluids. (<b>a</b>) Schematic illustration of SHIFT nanoICG preparation. (<b>b</b>) Dimensional characterization of nanoICG. (<b>c</b>,<b>d</b>) Anti-photobleaching experiments of free ICG and nanoICG, and the semi-quantitative analysis. Reprinted with permission from Ref. [<a href="#B32-bioengineering-11-00788" class="html-bibr">32</a>]. Copyright 2022 Springer Nature. (<b>e</b>) Preparation of nanoDOX via SPFT. (<b>f</b>) Dimensional characterization of nanoDOX. (<b>g</b>) The contact angle of free DOX and nanoDOX. The blue line simulates the horizontal plane that carries the bottom of the droplet [<a href="#B39-bioengineering-11-00788" class="html-bibr">39</a>].</p>
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<p>(<b>a</b>) A schematic diagram illustrating the synthesis of nano 5-Fu via SPFT. The arrows in the figure indicate the procedure for preparing Nano Fu using the SPFT technique. (<b>b</b>–<b>e</b>) Characterization of carrier-free nano 5-Fu. Reprinted with permission from Ref. [<a href="#B40-bioengineering-11-00788" class="html-bibr">40</a>]. Copyright 2023 Elsevier. (<b>f</b>) Schematic illustration of the preparation of nanoSU6668. (<b>g</b>) Characterization of SU6668 and nanoSU6668. (<b>h</b>) In vivo dual-PAI images of neovascularized eyes after topical administration of NanoSU6668. The white area is the approximate eye area, and both the red and blue areas are PA oxygen saturation signals, with blue indicating a low signal and red a high signal. Reprinted with permission from Ref. [<a href="#B41-bioengineering-11-00788" class="html-bibr">41</a>]. SPFT technique enhances the solubility of hydrophobic drugs in water by reducing the particle size [<a href="#B41-bioengineering-11-00788" class="html-bibr">41</a>]. SU6668, an anti-angiogenic oncology therapeutic drug, has a high degree of hydrophobicity that complicates the development of clinical formulations, and the addition of numerous excipients in the formulations poses many challenges in large-scale production. A SPFT strategy was used to synthesize carrier-free pure SU6668 nanoparticles (nano-SU6668), which exhibit uniform particle size (135 nm) with enhanced aqueous dispersibility, and thus exhibit excellent potential for improving drug delivery efficiency and prolonging in vivo circulation time (<a href="#bioengineering-11-00788-f004" class="html-fig">Figure 4</a>f–h).</p>
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<p>(<b>a</b>) Schematic illustration of SHIFT nanoICG preparation and fluorescence-guided precise hepatectomy. (<b>b</b>) Embolism and safety evaluation in clinical case of HCC. Red boxes and arrows are used to indicate the site of the tumor. (<b>c</b>) Surgical navigation effect of SHIFT nanoICG after long-lasting TAE-assisted therapy for varying degrees of lesions. White arrows are used to indicate tumor sites, red boxes and red arrows are used to indicate small tumor foci (A, preoperative three-dimensional reconstruction of hepatic resection; B, fluorescence imaging of the primary lesion; C, fluorescence imaging of the cut edge of the residual liver; D–F, whole resected tumor foci and fluorescence imaging; G–I, resected tumor foci and fluorescence imaging; J–L, layer-by-layer resected tumor foci and fluorescence imaging; M–N, microsatellite foci and fluorescence imaging; O, HE staining of microsatellite foci) [<a href="#B30-bioengineering-11-00788" class="html-bibr">30</a>].</p>
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<p>(<b>a</b>) Schematic illustration of SHIFT&amp;DOX preparation and transarterial chemoembolization of HCC [<a href="#B39-bioengineering-11-00788" class="html-bibr">39</a>]. (<b>b</b>) The preclinical development stages of nano 5-Fu, including production, characterization, in vitro and in vivo evaluation, and subsequent clinical trials, are investigated. Reprinted with permission from Ref. [<a href="#B40-bioengineering-11-00788" class="html-bibr">40</a>].</p>
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18 pages, 3454 KiB  
Article
“BrainHeart”: Pilot Study on a Novel Application for Elderly Well-Being Based on Mindfulness Acceptance and Commitment Therapy
by Roberta Bruschetta, Desiree Latella, Caterina Formica, Simona Campisi, Chiara Failla, Flavia Marino, Serena Iacono Isidoro, Fabio Mauro Giambò, Lilla Bonanno, Antonio Cerasa, Angelo Quartarone, Silvia Marino, Giovanni Pioggia, Rocco Salvatore Calabrò and Gennaro Tartarisco
Bioengineering 2024, 11(8), 787; https://doi.org/10.3390/bioengineering11080787 - 3 Aug 2024
Viewed by 370
Abstract
The rising prevalence of mental illness is straining global mental health systems, particularly affecting older adults who often face deteriorating physical health and decreased autonomy and quality of life. Early detection and targeted rehabilitation are crucial in mitigating these challenges. Mindfulness acceptance and [...] Read more.
The rising prevalence of mental illness is straining global mental health systems, particularly affecting older adults who often face deteriorating physical health and decreased autonomy and quality of life. Early detection and targeted rehabilitation are crucial in mitigating these challenges. Mindfulness acceptance and commitment therapy (ACT) holds promise for enhancing motivation and well-being among the elderly, although delivering such psychological interventions is hindered by limited access to services, prompting exploration of remote delivery options like mobile applications. In this paper, we introduce the BrainHeart App (v.1.1.8), a mobile application tailored to improve physical and mental well-being in seniors. The app features a 10-day ACT program and other sections promoting healthy lifestyle. In a pilot study involving twenty participants, individuals engaged in daily mental exercises for 10 days using the app. Clinical evaluations, including assessments of psychological flexibility, overall cognitive profile, mindfulness disposition, cognitive fusion, and heart rate collected with Polar H10, were conducted at baseline (T0) and one month post-intervention (T1). Analysis revealed significant improvements in almost all neuropsychological scores, with high usability reported (system usability scale average score: 82.3 ± 9.31). Additionally, a negative correlation was found between usability and experiential avoidance (r = −0.51; p = 0.026), and a notable difference in heart rate was observed between baseline and post-intervention (F-value = 3.06; p-value = 0.09). These findings suggest that mindfulness-ACT exercises delivered via the BrainHeart App can enhance the well-being of elderly individuals, highlighting the potential of remote interventions in addressing mental health needs in this population. Full article
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<p>Sections of BrainHeart mobile application to promote overall psycho-physical well-being.</p>
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<p>Example of nutrition tips and setting of dietary habits.</p>
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<p>Example of personalized physical exercises program.</p>
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<p>Example of data collection through the integration of a Polar H10 chest heat rate sensor.</p>
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<p>Example of meditation exercise included in the mindfulness section.</p>
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<p>The Hexaflex Model.</p>
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<p>A participant wearing a T-shirt equipped with a Polar H10 sensor for measuring heart rate variability interacts with the BrainHeart application using her smartphone.</p>
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<p>Bar plot of the assessed scores at T0 and T1 with significance level from paired-samples Wilcoxon test. Legend: ns = <span class="html-italic">p</span> &gt; 0.05, ** = <span class="html-italic">p</span> ≤ 0.01, *** = <span class="html-italic">p</span> ≤ 0.001. Prior to visualization, all scores were normalized through logarithmic transformation.</p>
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<p>Scatter plot between system usability scale and experiential avoidance variation (T1-T0) with Spearman correlation coefficient and <span class="html-italic">p</span>-value.</p>
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15 pages, 2577 KiB  
Review
A Review of Medical Image Registration for Different Modalities
by Fatemehzahra Darzi and Thomas Bocklitz
Bioengineering 2024, 11(8), 786; https://doi.org/10.3390/bioengineering11080786 - 2 Aug 2024
Viewed by 359
Abstract
Medical image registration has become pivotal in recent years with the integration of various imaging modalities like X-ray, ultrasound, MRI, and CT scans, enabling comprehensive analysis and diagnosis of biological structures. This paper provides a comprehensive review of registration techniques for medical images, [...] Read more.
Medical image registration has become pivotal in recent years with the integration of various imaging modalities like X-ray, ultrasound, MRI, and CT scans, enabling comprehensive analysis and diagnosis of biological structures. This paper provides a comprehensive review of registration techniques for medical images, with an in-depth focus on 2D-2D image registration methods. While 3D registration is briefly touched upon, the primary emphasis remains on 2D techniques and their applications. This review covers registration techniques for diverse modalities, including unimodal, multimodal, interpatient, and intra-patient. The paper explores the challenges encountered in medical image registration, including geometric distortion, differences in image properties, outliers, and optimization convergence, and discusses their impact on registration accuracy and reliability. Strategies for addressing these challenges are highlighted, emphasizing the need for continual innovation and refinement of techniques to enhance the accuracy and reliability of medical image registration systems. The paper concludes by emphasizing the importance of accurate medical image registration in improving diagnosis. Full article
(This article belongs to the Special Issue Optical Imaging for Biomedical Applications)
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<p>Illustration of different types of image registration in medical imaging. The figure displays four quadrants representing various registration scenarios. The top-left quadrant depicts multimodal image registration, aligning images acquired from different sensors or modalities. The top-right quadrant shows unimodal registration, aligning images obtained from the same modality or sensor. The bottom-left quadrant illustrates interpatient registration, aligning images from different individuals. Finally, the bottom-right quadrant represents intra-patient registration, aligning images obtained from the same individual over time, either on the same day or on different days.</p>
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<p>General framework of image registration. This figure presents a comprehensive overview of the image registration process, showcasing both classical and deep learning approaches. The framework includes two input images, a fixed image (<math display="inline"><semantics> <mrow> <msub> <mrow> <mi>I</mi> </mrow> <mrow> <mi>F</mi> </mrow> </msub> </mrow> </semantics></math>) and a moving image (<math display="inline"><semantics> <mrow> <msub> <mrow> <mi>I</mi> </mrow> <mrow> <mi>M</mi> </mrow> </msub> </mrow> </semantics></math>). In the classical registration area, alignment metrics, transformation, and optimization are depicted as key components, emphasizing their iterative interaction for achieving accurate alignment. Additionally, the deep learning registration section showcases the inclusion of a loss function, implicit transformation, and optimization within the iterative process.</p>
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<p>Different types of transformation. This figure illustrates various transformations applied to an original image. (1) Rigid transformation preserves distances and angles; (2) affine transformation incorporates translation, rotation, scaling, and shearing; (3) projective transformation accommodates perspective distortions; and (4) nonlinear deformation addresses intricate deformations. The original image is displayed alongside the transformed versions for comparison.</p>
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<p>This figure illustrates three common types of errors encountered during image registration. In the left panel, a matching error is depicted where key points (denoted by colored markers) in the fixed image fail to align precisely with the corresponding key points in the moving image. This discrepancy underscores the challenge of achieving accurate correspondence between key points in image registration. In the center panel, an alignment error is observed. Here, the vertebral column exhibits misalignment when comparing images, as indicated by the highlighted deviation (red oval) from the expected anatomical alignment. Addressing such alignment discrepancies is crucial for ensuring precise image registration and clinical assessment. The right panel illustrates a localization error where the placement of a key point inaccurately corresponds to the targeted anatomical feature. This means that, while the key point is present in both the reference (fixed) and moving images, its position is shifted or misaligned relative to its intended anatomical location. Inaccuracies like these can significantly affect the precision of diagnostic evaluations and treatment planning. Such errors can significantly impact the diagnostic accuracy and subsequent treatment planning processes. Each type of error underscores distinct challenges in achieving precise and reliable image registration.</p>
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<p>Classification of registration methods. This figure presents a comprehensive classification scheme for registration methods, highlighting five main subsets: modalities, type of transformation, interaction, classical techniques, and learning-based techniques. Each subset further encompasses various subcategories, providing a detailed taxonomy for organizing and understanding different registration approaches.</p>
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<p>Number of publications in classical image registration versus deep learning image registration in recent years. This plot provides a comparative analysis of the number of publications in classical image registration and deep learning image registration over the past 10 years (2013–2023) [<a href="#B47-bioengineering-11-00786" class="html-bibr">47</a>]. The red line represents the publications in classical image registration, while the green line represents the publications in deep learning image registration. The figure highlights the evolving trends and growing interest in deep learning approaches within the field of image registration, indicating a shift towards leveraging neural networks and machine learning techniques for improved registration performance.</p>
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