Search Results (450)

The pericellular matrix (PCM) is a specialized extracellular matrix that surrounds cells. Interactions with the PCM enable the cells to sense and respond to mechanical signals, triggering a proper adaptive response. Collagen VI is a component of muscle and tendon PCM. Mutations in collagen VI genes cause a distinctive group of inherited skeletal muscle diseases, and Ullrich congenital muscular dystrophy (UCMD) is the most severe form. In addition to muscle weakness, UCMD patients show structural and functional changes of the tendon PCM. In this study, we investigated whether PCM alterations due to collagen VI mutations affect the response of tendon fibroblasts to mechanical stimulation. By taking advantage of human tendon cultures obtained from unaffected donors and from UCMD patients, we analyzed the morphological and functional properties of cellular mechanosensors. We found that the length of the primary cilia of UCMD cells was longer than that of controls. Unlike controls, in UCMD cells, both cilia prevalence and length were not recovered after mechanical stimulation. Accordingly, under the same experimental conditions, the activation of the Hedgehog signaling pathway, which is related to cilia activity, was impaired in UCMD cells. Finally, UCMD tendon cells exposed to mechanical stimuli showed altered focal adhesions, as well as impaired activation of Akt, ERK1/2, p38MAPK, and mechanoresponsive genes downstream of YAP. By exploring the response to mechanical stimulation, for the first time, our findings uncover novel unreported mechanistic aspects of the physiopathology of UCMD-derived tendon fibroblasts and point at a role for collagen VI in the modulation of mechanotransduction in tendons. Full article

Rice is an important diet source for the majority of the world’s population, and meeting the growing need for rice requires significant improvements at the production level. Hybrid rice production has been a significant breakthrough in this regard, and the floral traits play a major role in the development of hybrid rice. In grass species, rice has structural units called florets and spikelets and contains different floret organs such as lemma, palea, style length, anther, and stigma exsertion. These floral organs are crucial in enhancing rice production and uplifting rice cultivation at a broader level. Recent advances in breeding techniques also provide knowledge about different floral organs and how they can be improved by using biotechnological techniques for better production of rice. The rice flower holds immense significance and is the primary focal point for researchers working on rice molecular biology. Furthermore, the unique genetics of rice play a significant role in maintaining its floral structure. However, to improve rice varieties further, we need to identify the genomic regions through mapping of QTLs (quantitative trait loci) or by using GWAS (genome-wide association studies) and their validation should be performed by developing user-friendly molecular markers, such as Kompetitive allele-specific PCR (KASP). This review outlines the role of different floral traits and the benefits of using modern biotechnological approaches to improve hybrid rice production. It focuses on how floral traits are interrelated and their possible contribution to hybrid rice production to satisfy future rice demand. We discuss the significance of different floral traits, techniques, and breeding approaches in hybrid rice production. We provide a historical perspective of hybrid rice production and its current status and outline the challenges and opportunities in this field. Full article

Integrated systems are facing complex and changing environments with the wide application of atmospheric LiDAR in civil, aerospace, and military fields. Traditional analysis methods employ optical software to evaluate the optical performance of integrated systems, and cannot comprehensively consider the influence of optical and mechanical coupling on the optical performance of the integrated system, resulting in the unsatisfactory accuracy of the analysis results. Optical–mechanical integration technology provides a promising solution to this problem. A small-field-of-view LiDAR system with high repetition frequency, low energy, and single-photon detection technology was taken as an example in this study, and the Zernike polynomial fitting algorithm was programmed to enable transmission between optical and mechanical data. Optical–mechanical integration technology was employed to obtain the optical parameters of the integrated system under a gravity load in the process of designing the optical–mechanical structure of the integrated system. The experimental validation results revealed that the optical–mechanical integration analysis of the divergence angle of the transmission unit resulted in an error of 2.586%. The focal length of the telescope increased by 89 μm, its field of view was 244 μrad, and the error of the detector target surface spot was 4.196%. The continuous day/night detection results showed that the system could accurately detect the temporal and spatial variations in clouds and aerosols. The inverted optical depths were experimentally compared with those obtained using a solar photometer. The average optical depth was 0.314, as detected using LiDAR, and 0.329, as detected by the sun photometer, with an average detection error of 4.559%. Therefore, optical–mechanical integration analysis can effectively improve the stability of the structure of highly integrated and complex optical systems. Full article

The numerical aperture (NA) of objective lens optical (inspection) systems has been increased to achieve higher resolution. However, the depth of focus decreases with an increase in the NA, and focusing becomes difficult. Therefore, the entire optical lens in currently developed optical inspection systems must be moved to focus within the depth of focus. To achieve a high resolution, many lenses are used in optical inspection systems, increasing the size and weight of the optical systems. To address this issue, a focus control group was placed on a tube lens that could adjust its focus based on the movement of the sample in front of the objective lens. Therefore, we developed a focus range increment to focus on the range of the optical inspection system. Using objective lenses with focal lengths of 30 and 60 mm and tube lenses with a focal length of 300 mm, optical systems for 10× and 5× inspection were constructed. In the designed optical systems, the weights of the objective lenses with focal lengths of 30 and 60 mm were calculated to be approximately 844 and 570 g, respectively. These values confirm that the weight of the moving group can be reduced. Full article

The (pro)renin receptor ((P)RR), a versatile protein found in various organs, including the kidney, is implicated in cardiometabolic conditions like diabetes, hypertension, and dyslipidemia, potentially contributing to organ damage. Importantly, changes in (pro)renin/(P)RR system localization during renal injury, a critical information base, remain unexplored. This study investigates the expression and topographic localization of the full length (FL)-(P)RR, its ligands (renin and prorenin), and its target cyclooxygenase-2 and found that they are upregulated in three distinct animal models of renal injury. The protein expression of these targets, initially confined to specific tubular renal cell types in control animals, increases in renal injury models, extending to glomerular cells. (P)RR gene expression correlates with protein changes in a genetic model of focal and segmental glomerulosclerosis. However, in diabetic and high-fat-fed mice, (P)RR mRNA levels contradict FL-(P)RR immunoreactivity. Research on diabetic mice kidneys and human podocytes exposed to diabetic glucose levels suggests that this inconsistency may result from disrupted intracellular (P)RR processing, likely due to increased Munc18-1 interacting protein 3. It follows that changes in FL-(P)RR cellular content mechanisms are specific to renal disease etiology, emphasizing the need for consideration in future studies exploring this receptor’s involvement in renal damage of different origins. Full article

Aiming at the problem that traditional design methods make it difficult to control the polarization aberration distribution of optical systems quickly and accurately, this study proposes an automatic optimization design method for polarization optical systems based on deep learning. The unsupervised training model based on ray tracing and polarized ray tracing was constructed by learning the reference lens structural feature data from the optical lens library, and the generalization ability of the deep neural network model was improved to achieve the automatic optimization design of the polarized optical system. The design results show that the optical system structure optimized by the network model is close to the reference lens in the full field of view and the full spectrum and that the optical system structure can be designed for different focal length requirements. The success rate of 1 million groups of initial structures designed is better than 96.403%, and the polarization effect of the optical system is effectively controlled. The proposed deep learning approach to optical design provides a new solution for future complex optical systems and also provides an effective way to improve the design accuracy of special optical systems such as polarization optical systems. Full article

Near-field bending of a laser diode bar (i.e., the SMILE effect) degrades the laser beam brightness, adversely affecting optical coupling and beam shaping. Previous reports mainly focused on the two-dimensional near-field bending of a laser diode bar. However, the near-field bending of a laser diode bar not only occurs in the laser bar growth direction, but also in the beam propagation direction. The present article proposes the three-dimensional near-field bending of a laser diode array, which is commonly known as the three-dimensional spatial SMILE effect. Through theoretical and simulated investigations, it has been found that a laser bar array not only deforms in the fast axis direction to cause the traditional two-dimensional SMILE effect but also experiences an additional deformation of approximately 2 μm in the laser emission direction simultaneously. Due to the SMILE effect in the beam propagation direction, not all emitters are aligned in a straight line, and some emitters experience defocusing during collimation. Consequently, there is an increase in the residual divergence angle and beam width, resulting in a degradation of the laser bar array’s beam quality. According to the theoretical calculations, ZEMAX simulations, and experimental results, for a FAC (fast axis collimation) with a focal length of 300 μm, the divergence angle of single emitter after collimating in the fast axis increases from 4.95 mrad to 6.46 mrad when the offsetting of the working distance between the incident beam waist and FAC lens increases from 0 μm to 2 μm. Full article

The role of chemical communication in the social relationships of birds is receiving growing attention, but our knowledge is still scarce compared to that of other taxa. Previous evidence suggests that chemical cues emitted by birds may carry information about their characteristics, which may be useful in the context of sexual selection. However, experimental studies are needed to investigate the role of bird chemical cues in signalling the quality of potential partners. We performed an experimental study aimed at disentangling whether the female Zebra Finches (Taeniopygia guttata), use chemical cues to assess the body condition of potential partners. We offered focal females (N = 28) the scent of two males differing in body condition (body mass/tarsus length ratio) (N = 28 scent donor males). Our results showed that females can assess the body condition of potential partners using olfaction. However, contrary to what should be expected in a mate choice context, females avoided the scent of males with greater body condition. Our results, therefore, suggest that, despite performing the study during the breeding period, social interactions may be mediating the avoidance of the scent of the male in better condition in this gregarious species, probably to avoid a conspecific competitor with better body condition. Full article

Currently, radio frequency (RF) waveforms are widely used in wireless communication systems and are widely used in many fields to improve human quality of life. In Internet of Things (IoT) systems and satellite systems, the installation and deployment of wireless communication systems have become easier and offer many advantages compared to wired communication. However, high RF frequencies can have detrimental effects on the human body. Therefore, the visible light bandwidth is being researched and used as a replacement for RF in certain wireless communication systems. Several strategies have been explored: free-space optics, light fidelity, visible light communication, and optical camera communication. By leveraging time-domain on–off keying, this article presents a multiple-input-multiple-output (MIMO) modulation technique using a light-emitting diode (LED) array designed for IoT applications. The proposed scheme is versatile and suitable for both roller shutter and global shutter cameras commonly found on the market, including CCTV cameras commonly found in factories and buildings. By using deep learning for threshold prediction, the proposed scheme could achieve better performance compared to the traditional scheme. Despite the compact size of the LED array, the precise control of the exposure time, camera focal length, and channel encoding enabled the successful implementation of this scheme and supported four links at various positions within a communication distance of 22 m, taking into account the mobility effect (3 m/s). Full article

Concentration of solar energy may be obtained by reflection, refraction, or a combination of the two. The collectors of a reflection system are designed to concentrate the sun’s rays onto a photovoltaic cell or steam tube. Refractive lenses concentrate light by having it travel through the lens. The sun’s rays are partially reflected and then refracted via a hybrid technique. Hybrid focus techniques have the potential to maximize power output. Fresnel lenses are an efficient tool for concentrating solar energy, which may then be used in a variety of applications. Development of both imaging and non-imaging devices is occurring at this time. Larger acceptance angles, better concentration ratios with less volume and shorter focal length, greater optical efficiency, etc., are only some of the advantages of non-imaging systems over imaging ones. This study encompasses numerical, experimental, and numerical and experimental studies on the use of Fresnel lenses in various solar energy systems to present a comprehensive picture of current scientific achievements in this field. The framework, design criteria, progress, and difficulties are all dissected in detail. Accordingly, some recommendations for further studies are suggested. Full article

To build a long-wave infrared catadioptric optical system for deep space low-temperature target detection with a lightweight and wide field of view, this work conducted a study that encompasses a local cooling optical system, topology optimization-based metal mirror design, and additive manufacturing. First, a compact catadioptric optical system with local cooling was designed. This system features a 55 mm aperture, a 110 mm focal length, and a 4-degree by 4-degree field of view. Secondly, we applied the principles of topology optimization to design the primary mirror assembly, the secondary mirror assembly, and the connecting baffle. The third and fourth modes achieved a resonance frequency of 1213.7 Hz. Then, we manufactured the mirror assemblies using additive manufacturing and single-point diamond turning, followed by the centering assembly method to complete the optical assembly. Lastly, we conducted performance testing on the system, with the test results revealing that the modulation transfer function (MTF) curves of the optical system reached the diffraction limit across the entire field of view. Remarkably, the system’s weight was reduced to a mere 96.04 g. The use of additive manufacturing proves to be an effective means of enhancing optical system performance. Full article

Based on the application requirements of high spectral resolutions, high spatial resolutions and wide swatches, a new-generation, high-performance, spaceborne, hyperspectral imaging spectrometer (NGHSI) with a spatial resolution of 15 m and a swatch of 90 km is proposed. The optical system of the NGHSI has a focal length of 1128 mm, an F-number of three, a field of view (FOV) of 7.32° and a slit length of 144 mm. A new off-axis, multi-mirror telescope structure with intermediate images is put forward, which solves the design problem that realizes secondary imaging and good telecentricity at the same time. And a new off-axis lens-compensation Offner configuration is adopted to address the challenge of the high-fidelity design of spectral imaging systems with long slit lengths. The relationship between X-Y polynomials and aberration coefficients is analyzed, and the X-Y polynomial freeform surfaces are used to correct the off-axis aberrations. The design results show that the image quality of the telescope system is close to the diffraction limit. The smile, known as the spectral distortion along the line, and keystone, which is the magnification difference for different wavelengths, of the spectral imaging system are less than 1/10 pixel size. The complete optical system of the NGHSI, including the telescope system and the spectral imaging system, has excellent imaging quality and the layout is compact and reasonable, which realizes the miniaturization design. Full article

To rapidly improve strontium optical clocks, a high-power, high-efficiency, and high-beam-quality 461 nm laser is required. In blue lasers based on periodically poled KTiOPO₄ crystals, the optical absorption in the crystals can induce thermal effects, which must be considered in the design of high-efficiency external-cavity frequency doubling lasers. The interdependence between the absorption and the thermally induced quasi-phase mismatch was taken into account for the solution to the coupled wave equations. By incorporating multilayer crystal approximation, a theoretical model was developed to accurately determine the absorption of the frequency doubling laser. Based on experimental parameters, the temperature gradient in the crystal, the influence of the boundary temperature on the conversion efficiency, and the focal length of the thermal lens were simulated. Theoretical calculations were employed to optimize the parameters of the external-cavity frequency doubling experiment. In the experiment, in a bow-tie external cavity was demonstrated by pumping a 10 mm long periodically poled KTiOPO₄ crystal with a 922 nm laser, a 461 nm laser with a maximum output power of 382 mW. The conversion efficiency of the incident fundamental laser was 66.2%. The M² factor of the frequency doubling beam was approximately 1.4. Full article

Background: Malnutrition is usual in patients referred for endoscopic gastrostomy (PEG). Refeeding syndrome is rarely observed in PEG-fed patients, which could possibly be associated with reduced absorption induced by prolonged starvation. Objective: In patients submitted to PEG after a significant period of fasting, the present study aims to: 1. evaluate the histological/ultrastructural initial changes in the intestinal mucosa, potentially associated with reduced absorption, and 2. assess if these changes could reverse with enteral refeeding. Methods: The present study is an observational, prospective, controlled study. Adult patients with ingestion below 50% of daily needs for at least one month and/or diagnosis of malnutrition were enrolled. Duodenal biopsies were taken at baseline and after 3–6 months of PEG feeding, which then underwent histological/ultrastructural analysis. Random healthy individuals were used as controls. Results: A total of 30 patients (16 men/14 women) aged 67.1 ± 13.5 years were included. Malnutrition was found in 40% of patients. Approximately 14 patients completed follow-up during both periods (46.7%). At baseline: duodenal mucosal atrophy was evident in three patients (10%); the median villi length (MVL) was 0.4 mm (0.25–0.6 mm), with it being shorter than the controls, which was 0.6 mm (0.4–0.7 mm) (p = 0.006); ultrastructural changes included focal shortening, bending, and disruption of enterocyte microvilli, the presence of citoplasmatic autophagic vacuoles, dilation and vesiculation of the smooth endoplasmic reticulum, and the presence of dilated intercellular spaces with basement membrane detachment. After refeeding, most patients displayed normal histology (92.9%) and increase MVL (p < 0.001), ultrastructural changes disappeared, and enterocytes resumed a normal appearance, although retaining scarce, small, dense bodies in apical regions from the evolution of previous autophagy. Conclusions: Prolonged fasting induces histological and ultrastructural changes in the intestinal mucosa that may reflect impaired absorption in the early post-PEG period. These changes were reverted after refeeding with enteral nutrition. Full article

Background: Stent implantation represents the standard of care in coronary intervention. While a short stent implanted on a focal lesion located on the left anterior descending artery (LAD) seems a reasonable alternative to an internal mammary implant, the same for long stents is still debated. Methods: We reported the long-term data of 531 consecutive patients who underwent Percutaneous Coronary Intervention (PCI) with long stents in two highly specialized centres. The main inclusion criteria were the implantation of stents longer than 30 mm on the LAD and a minimum follow-up (FU) of five years. The primary endpoint was mortality, and the secondary endpoints were any myocardial infarction (MI), target vessel and lesion revascularization (TVR and TLR, respectively), and stent thrombosis (ST) observed as definite, probable, or possible. Results: In this selected population with characteristics of complex PCI (99.1%), the long-term follow-up (mean 92.18 ± 35.5 months) estimates of all-cause death, cardiovascular death, and any myocardial infarction were 18.3%, 10.5%, and 9.3%, respectively. Both all-cause and cardiovascular deaths are significantly associated with three-vessel disease (HR 6.8; confidence of interval (CI) 95% 3.844–11.934; p < 0.001, and HR 4.7; CI 95% 2.265–9.835; p < 0.001, respectively). Target lesion (TLR) and target vessel revascularization (TVR) are associated with the presence of three-lesion disease on the LAD (HR 3.4; CI 95% 1.984–5.781; p < 0.001; HR 3.9 CI 95% 2.323–6.442; p < 0.001, respectively). Re-PCI for any cause occurred in 31.5% of patients and shows an increased risk for three-lesion stenting (HR 4.3; CI 95% 2.873–6.376; p < 0.001) and the treatment of bifurcation with two stents (HR 1.6; 95% CI 1.051–2.414; p = 0.028). Stent thrombosis rate at the 5-year FU was 4.4% (1.3% definite; 0.9% probable; 2.1% possible), including a 1.7% rate of very-late thrombosis. The stent length superior to 40 mm was not associated with poor outcomes (all-cause death p = 0.349; cardiovascular death p = 0.855; MI p = 0.691; re-PCI p = 0.234; TLR p = 0.805; TVR p = 0.087; ST p = 0.189). Conclusion: At an FU of longer than five years, patients treated with stents longer than 30 mm in their LAD showed acceptable procedural results but poor outcomes. Full article