Search Results (2,596)

Blood pressure measurement is a key indicator of vascular health and a routine part of medical examinations. Given the ability of photoplethysmography (PPG) signals to provide insights into the microvascular bed and their compatibility with wearable devices, significant research has focused on using PPG signals for blood pressure estimation. This study aimed to identify specific clinical PPG features that vary with different blood pressure levels. Through a literature review of 297 publications, we selected 16 relevant studies and identified key time-dependent PPG features associated with blood pressure prediction. Our analysis highlighted the second derivative of PPG signals, particularly the $b/a$ and $d/a$ ratios, as the most frequently reported and significant predictors of systolic blood pressure. Additionally, features from the velocity and acceleration photoplethysmograms were also notable. In total, 29 features were analyzed, revealing novel temporal domain features that show promise for further research and application in blood pressure estimation. Full article

Background and objective: Extending a consistent pharmacy antimicrobial stewardship weekend service was a newly implemented initiative. We sought to evaluate the impact of incorporating an Infectious Diseases (ID)-trained clinical pharmacist into an antimicrobial stewardship program (AMS) during weekends. Results: The number of documented interventions was 451 on 362 patients compared to 115 interventions on 108 patients during the pre-implementation period (p = 0.04), with interventions primarily targeting Watch antibiotics, as classified by the WHO AWaRe classification. A reduction in the LOS was observed, with a median of 16 days (8–34) during the post-implementation period compared to 27.5 days (10–56) during the pre-implementation period (p = 0.001). The median DOT increased during the post-implementation period to 8 (6–11), versus the increase to 7 (4–11) during the pre-implementation period (p ≤ 0.001). Finally, there was no significant difference observed in healthcare-associated CDI and infection-related readmission. Methods: This is a retrospective single-center, pre–post quasi-experimental study. Data including the documented pharmacist interventions were collected from the electronic medical record (EMR), the pre-implementation phase was in 2020, and post-implementation was in 2021. The primary outcome was to identify the number of AMS interventions through prospective audit and feedback review analysis. Secondary outcomes included antibiotic days of therapy (DOT), length of hospital stay (LOS), healthcare-associated Clostridioides difficile infection (CDI), and infection-related readmission. Conclusions: The pharmacist-driven weekend AMS is an opportunity for pharmacists to intervene and optimize patients’ care plans. This initiative demonstrated significant increased AMS-related interventions, promoted judicious antimicrobial use, and contributed to a reduced length of hospital stay. Our findings need to be replicated in a larger prospective study. Full article

Current XR applications move beyond audiovisual information, with haptic feedback rapidly gaining ground. However, current haptic devices are still evolving and often struggle to combine key desired features in a balanced way. In this paper, we propose the development of a high-resolution haptic (HRH) system for perception enhancement, a wearable technology designed to augment extended reality (XR) experiences through precise and localized tactile feedback. The HRH system features a modular design with 58 individually addressable actuators, enabling intricate haptic interactions within a compact wearable form. Dual ESP32-S3 microcontrollers and a custom-designed system ensure robust processing and low-latency performance, crucial for real-time applications. Integration with the Unity game engine provides developers with a user-friendly and dynamic environment for accurate, simple control and customization. The modular design, utilizing a flexible PCB, supports a wide range of actuators, enhancing its versatility for various applications. A comparison of our proposed system with existing solutions indicates that the HRH system outperforms other devices by encapsulating several key features, including adjustability, affordability, modularity, and high-resolution feedback. The HRH system not only aims to advance the field of haptic feedback but also introduces an intuitive tool for exploring new methods of human–computer and XR interactions. Future work will focus on refining and exploring the haptic feedback communication methods used to convey information and expand the system’s applications. Full article

Knowledge comes in various forms: scientific, artistic, legal, and many others. For most non-computer scientists, it is far easier to express their knowledge in text than in programming code. The dynamic decision tree system is a system for supporting the authoring of expertise in text form and navigation via an interface that limits the cognitive load on the reader. Specifically, as the reader answers questions, relevant tree nodes appear and irrelevant ones disappear. Searching by a keyword can help to navigate the tree. Database calls bring in information from external datasets. Links bring in other decision trees as well as websites. This paper describes the reader interface, the authoring interface, the related state-of-the-art work, the implementation, and case studies. Full article

Functionally Graded Metamaterials (FGMMs) constitute an innovative class of materials within the realm of additive manufacturing (AM), attracting substantial attention from material science and research communities. These materials, characterized by unique designs and gradient properties, are not commonly found in nature but are deliberately engineered through the arrangement of subwavelength structures. The distinct attributes of such materials have propelled them into significant prominence across various industries, including automotive, aerospace, medical, electronics, and agriculture. This review paper aims to present a comprehensive overview of a range of techniques applied in the fabrication, design, theoretical models, and simulation methods related to these materials. It delves into the assessment of such material’s performance, specifically focusing on mechanical, thermal, and electromagnetic properties. Moreover, this review addresses advancements, challenges, and potential solutions in the field. Ultimately, it delivers valuable insights to researchers, practitioners, and stakeholders, enhancing their understanding of FGMMs and their significance in the broader context. Full article

The aim of this work is to examine some q-analogs and differential properties of the gamma integral operator and its convolution products. The q-gamma integral operator is introduced in two versions in order to derive pertinent conclusions regarding the q-exponential functions. Also, new findings on the q-trigonometric, q-sine, and q-cosine functions are extracted. In addition, novel results for first and second-order q-differential operators are established and extended to Heaviside unit step functions. Lastly, three crucial convolution products and extensive convolution theorems for the q-analogs are also provided. Full article

This research presents a system dynamics model to study the interaction among demand and supply evolutions, government regulations, sustainable adoption trends, investments in different decarbonization technologies, and environmental requirements for the European Aluminum Rolled Product Supply Chain (ARPSC). It allows stakeholders to assess the quantitative impact of investing in decarbonization technologies on supply chain sustainability. Investing in decarbonization technologies reduces greenhouse gas (GHG) emissions. The most substantial GHG emission reductions can be achieved if upstream ARPSC actors invest according to an aggressive investment strategy between 2031 and 2040. However, even with an aggressive investment strategy, investing in decarbonization technologies alone is likely to be insufficient to achieve the European Green Deal goals. Furthermore, barriers to investment in decarbonization technologies and a low rate of progress in doubling the European Union’s circularity rate may put extra stress on achieving the European Green Deal goals for the European ARPSC. Instead, ARPSC actors will additionally need to optimize the recycling of aluminum rolled products and adopt strategies for resource sufficiency, e.g., by sharing cars and using packaging multiple times. Full article

Quantum-secure cryptography is a dynamic field due to its crucial role in various domains. This field aligns with the ongoing efforts in data security. Post-quantum encryption (PQE) aims to counter the threats posed by future quantum computers, highlighting the need for further improvement. Based on the learning with error (LWE) system, this paper introduces a novel asymmetric encryption technique that encrypts entire messages of n bits rather than just 1 bit. This technique offers several advantages including an additive homomorphic cryptosystem. The robustness of the proposed lightweight public key encryption method, which is based on a new version of LWE, ensures that private keys remain secure and that original data cannot be recovered by an attacker from the ciphertext. By improving encryption and decryption execution time—which achieve speeds of 0.0427 ms and 0.0320 ms, respectively—and decreasing ciphertext size to 708 bits for 128-bit security, the obtained results are very promising. Full article

Owing to their unique physicochemical properties, MXenes have emerged as promising materials for biosensing applications. This review paper comprehensively explores the recent advancements in MXene-based biosensors for health and environmental applications. This review begins with an introduction to MXenes and biosensors, outlining various types of biosensors including electrochemical, enzymatic, optical, and fluorescent-based systems. The synthesis methods and characteristics of MXenes are thoroughly discussed, highlighting the importance of these processes in tailoring MXenes for specific biosensing applications. Particular attention is given to the development of electrochemical MXene-based biosensors, which have shown remarkable sensitivity and selectivity in detecting various analytes. This review then delves into enzymatic MXene-based biosensors, exploring how the integration of MXenes with enzymes enhances sensor performance and expands the range of detectable biomarkers. Optical biosensors based on MXenes are examined, focusing on their mechanisms and applications in both healthcare and environmental monitoring. The potential of fluorescent-based MXene biosensors is also investigated, showcasing their utility in imaging and sensing applications. In addition, MXene-based potential wearable biosensors have been discussed along with the role of MXenes in volatile organic compound (VOC) detection for environmental applications. Finally, this paper concludes with a critical analysis of the current state of MXene-based biosensors and provides insights into future perspectives and challenges in this rapidly evolving field. Full article

In recent years, energy conservation became a strategic goal to preserve the environment, foster sustainability, and preserve valuable natural resources. The building sector is considered one of the largest energy consumers globally. Therefore, insulation plays a vital role in mitigating the energy consumption of the building sector. This study provides an overview of various organic and inorganic insulation materials, recent trends in insulation systems, and their applications, advantages, and disadvantages, particularly those suitable for extreme climates. Moreover, natural and composite materials that can be used as a low-cost, thermally efficient, and sustainable option for thermal insulation are discussed along with their thermal properties-associated problems, and potential solutions that could be adopted to utilize natural and sustainable options. Finally, the paper highlights factors affecting thermal performance and essential considerations for choosing a particular insulation system for a particular region. It is concluded that the most commonly used insulation materials are found to have several associated problems and there is a strong need to utilize sustainable materials along with advanced materials such as aerogels to develop novel composite insulation materials to overcome these deficiencies. Full article

Sand cats, Felis margarita, range from northern Africa and the Arabian Peninsula to Central Asia. Their apparently discontinuous distribution is recognized as comprising four subspecies. Recent genetic research found little differentiation between subspecies except for the North African form. In this study, 90 skins and 88 skulls were analyzed from the four subspecies. A discriminant function analysis of the scores, ranging from 1 to 4, of four pelage characteristics revealed differentiation between putative subspecies, except between Turkmenian and Pakistani sand cats. Northern African and Arabian sand cats tend to be spotted and striped, while Turkmenian and Pakistani sand cats are less spotted and have a dorsal crest of fur. Nonmetric multidimensional scaling (NMDS) models generated from 21 skull measurements revealed an overlap in morphospace between all subspecies, except for larger Turkmenian sand cats; northern African sand cats were smallest. Therefore, both pelage characteristics and skull morphometrics support up to three subspecies. However, considering recent genetic research, it is likely that two subspecies should be recognized, F. m. margarita from northern Africa and F. m. thinobia from the Arabian Peninsula, and Southwest and Central Asia. Widening of the dataset and nuclear DNA evidence are required to increase our understanding of geographical variation in this little studied species. Full article

Airborne dust easily accumulates on the top of solar panel surfaces and reduces the output power in arid regions. A commonly used mitigation solution for dust deposition issues is cleaning PV panels periodically. However, cleaning frequency affects the economic viability of solar PV systems, resulting in a trade-off between cleaning costs and energy loss costs. To address this issue, this study relates several metrics and develops a generic framework based on simulation and optimization to determine the optimal cleaning interval. Based on the computational tests, the optimal cleaning interval in Abu Dhabi is determined to be 34 days, which is longer than the currently recommended cleaning interval of 28 days. This study also identifies that energy recovery is responsive to decreases in unit cleaning costs in the presence of high electricity tariffs, whereas total cost savings show sensitivity when electricity tariffs are low. Finally, this study discusses energy policy implications by presenting an innovative concept involving the introduction of a cleaning subsidy which could reshape energy system cost dynamics, making PV systems economically competitive beyond the conventional levelized cost of electricity. Full article

Lead sulfide (PbS) on the nanoscale was synthesized via a chemical route at room temperature using lead nitrate {Pb(NO₃)₂} and sodium sulfide (Na₂S). The Na₂S was prepared at ~105 °C using sodium hydroxide (NaOH) and sulfur (S) powder. The produced PbS, denoted as Lab-PbS, was compared with a high-concentration PbS phase of galena. The produced Na₂S and Lab-PbS were examined using scanning electron microscopy and energy dispersive X-ray spectroscopy for microstructural and chemical analysis. The results confirmed a high-purity PbS compound (>99%) with a nanoscale particle size. The results showed that ultrasonic agitation was vital for obtaining the nanoparticle size of the Lab-PbS. Furthermore, thin films from the synthesized Lab-PbS and galena were successfully thermally evaporated on glass, quartz, and silicon substrates. The formation of nanometric grains was confirmed by scanning electron microscopy (SEM). XRD and FTIR spectroscopy were carried out for the Lab-PbS, galena fine powders, and galena thin films. The average crystal diameter was calculated for the galena thin films and was found to be approximately 26.6 nm. Moreover, the UV–Visible transmission curve was measured for the thin films in the wavelength range of 200–1100 nm in order to calculate the bandgap energy (E_g) for the thin films. The values of E_g were approximately 2.65 eV and 2.85 eV for the galena and Lab-PbS thin films, respectively. Finally, the sintering of the Lab-PbS and galena powders was carried out at ~700 °C for 1 h under vacuum, achieving relative densities of ~98.1% and ~99.2% for the Lab-PbS and galena, respectively. Full article

In lithium–polymer batteries, the electrolyte is an essential component that plays a crucial role in ion transport and has a substantial impact on the battery’s overall performance, stability, and efficiency. This article presents a detailed study on developing nanostructured composite polymer electrolytes (NCPEs), prepared using the solvent casting technique. The materials selected for this investigation include poly(vinyl chloride) (PVC) as the host polymer, lithium bromide (LiBr) as the salt, and silica (SiO₂) as the nanofiller. The addition of nano-SiO₂ dramatically enhanced the ionic conductivity of the electrolytes, with the highest value of 6.2 × 10⁻⁵ Scm⁻¹ observed for the sample containing 7.5 wt% nano-SiO₂. This improvement is attributed to an increased amorphicity resulting from the interactions between the polymer, salt, and filler components. A structural analysis of the prepared NCPEs using X-ray diffraction revealed the presence of both crystalline and amorphous phases, further validating the enhanced ionic transport. Additionally, the thermal stability of the NCPEs was found to be excellent, withstanding temperatures up to 334 °C, thereby reinforcing their potential application in lithium–polymer batteries. This work explores the electrochemical performance of a fabricated lithium-ion-conducting primary electrochemical cell (Zn + ZnSO₄·7H₂O|PVC: LiBr: SiO₂|PbO₂ + V₂O₅), which demonstrated an open circuit voltage of 2.15 V. The discharge characteristics of the fabricated cell were thoroughly studied, showcasing the promising potential of these NCPEs. With the support of superior morphological and electrical properties, as-prepared electrolytes offer an effective pathway for future advancements in lithium–polymer battery technology, making them a highly viable candidate for enhanced energy storage solutions. Full article

In this article, the $(p,q)$-analogs of the $\alpha$-th fractional Fourier transform are provided, along with a discussion of their characteristics in specific classes of $(p,q)$-generalized functions. Two spaces of infinitely $(p,q)$-differentiable functions are defined by introducing two $(p,q)$-differential symmetric operators. The $(p,q)$-analogs of the $\alpha$-th fractional Fourier transform are demonstrated to be continuous and linear between the spaces under discussion. Next, theorems pertaining to specific convolutions are established. This leads to the establishment of multiple symmetric identities, which in turn requires the construction of $(p,q)$-generalized spaces known as $(p,q)$-Boehmians. Finally, in addition to deriving the inversion formulas, the generalized $(p,q)$- analogs of the $\alpha$-th fractional Fourier transform are introduced, and their general properties are discussed. Full article