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BACKGROUND: Wound healing complications are a major challenge following the extended lateral approach in calcaneal fractures. Soft-tissue microcirculation plays an important role via the delivery of oxygen, nutrients, and the regulation of a local milieu. The aim of this clinical study was to examine the effect of intraoperative pneumatic tourniquet application on skin and subcutaneous microcirculation, and its impact on wound healing progression. METHODS: Patients with calcaneal fractures were randomly assigned to two groups defined by a surgery conducted either with use or without use of a tourniquet. Blood flow (BF [AU]), tissue oxygen saturation (SO2[%]) and the relative amount of haemoglobin (rHb[AU]) were intraoperatively measured at two depths (2 and 8 mm) non-invasively by spectrophotometry (Micro-Lightguide O2C®, LEA Medizintechnik, Giessen, Germany). Time points were before and after inflation of the pneumatic tourniquet and also at the end of surgery before deflation. A linear mixed model (LMM) was fitted for statistical analysis. RESULTS: Thirty-four patients (3 women and 31 men) with 37 calcaneal fractures were included. In 22 of them, the surgery was conducted with a tourniquet and in the other 15 without its use. A significant decrease of microcirculation, characterized by decreases in blood flow (p = 0.011) and tissue oxygenation (p = 0.023) was measured in 8 mm depth after inflating the tourniquet. However, these changes did not influence the time of postoperative wound healing. CONCLUSION: The use of a pneumatic tourniquet reduces deep microcirculation without affecting postoperative wound healing. Trial registration The study was registered in www. CLINICALTRIALS: gov (NCT01264146).

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Background/Objectives: Keratoconus (KC) is a bilateral eye disease characterized by corneal thinning and cone-like deformation, leading to visual impairment. This study evaluated the radial peripapillary capillaries (RPCs) in keratoconus patients with and without penetrating keratoplasty (PKP) using OCT and angio-OCT, comparing the results to a control group. Methods: This retrospective study included 149 eyes, 97 from patients who underwent PKP between January 2018 and February 2023 and 52 from patients who did not undergo PKP. The control group comprised 72 patients (144 eyes) who were healthy volunteers. Measurements included the best corrected visual acuity (BCVA), the intraocular pressure (IOP), slit-lamp biomicroscopy, a fundus examination, and corneal topography, as well as OCT and angio-OCT assessments of the RPCs, retinal nerve fiber layer (RNFL), ganglion cell complex (GCC), and central retinal thickness (CRT). Statistical analyses were performed using Student's t-test and Pearson's correlation coefficient. Results: The RNFL was significantly thinner in KC eyes after PKP compared to control eyes (p < 0.001), and the CRT was significantly thicker in KC eyes after PKP compared to control eyes (p = 0.003). However, the GCC was similar across the groups (p = 0.0885). Additionally, RPCs inside the disc were significantly reduced in KC eyes after PKP compared to control eyes (p < 0.0001). A significant positive correlation was found between RPC whole vessel density and RNFL thickness as measured via angio-OCT (r = 0.308, p < 0.0001). Conclusions: This study found that the RPC density inside the disc is significantly reduced in keratoconus patients after penetrating keratoplasty, highlighting RPCs inside the disc as a potential diagnostic tool for further assessment of keratoconus.

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The close spatial relationship between microglia and cerebral blood vessels implicates microglia in vascular development, homeostasis and disease. In this study we used the publicly available Cortical MM^3 electron microscopy dataset to systematically investigate microglial interactions with the vasculature. Our analysis revealed that approximately 20% of microglia formed direct contacts with blood vessels through gaps between adjacent astrocyte endfeet. We termed these contact points "plugs". Plug-forming microglia exhibited closer proximity to blood vessels than non-plug forming microglia and formed multiple plugs, predominantly near the soma, ranging in surface area from ∼0.01 µm2 to ∼15 µm2. Plugs were enriched at the venule end of the vascular tree and displayed a preference for contacting endothelial cells over pericytes at a ratio of 3:1. In summary, we provide novel insights into the ultrastructural relationship between microglia and the vasculature, laying a foundation for understanding how these contacts contribute to the functional cross-talk between microglia and cells of the vasculature in health and disease.

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PURPOSE: This study was performed to assess the prevalence of the vascularized foveal zone, including macular-foveal capillaries (MFC) and congenital retinal macrovessels (CRM), and to analyze the structural characteristics of the macular area in patients with MFC. MATERIAL AND METHODS: The first phase of the study evaluated the prevalence of MFC and CRM. Optical coherence tomography angiography (OCT-A) was performed, and OCT-A images of the foveal avascular zone were analyzed. In the second phase, two groups were formed: the MFC group (12 eyes, 9 patients, mean age 43.8±10.7 years) and the control group (18 eyes, 17 patients, mean age 43.0±11.8 years). A comparative analysis was performed assessing central retinal thickness (CRT), thickness of retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), and foveal pit depth. RESULTS: MFCs were detected in 45 eyes from a total sample of 1031 eyes of 536 patients. The presence of CRM was recorded in three eyes of three patients. RNFL thickness was significantly higher in the MFC group in the inferior parafoveal sector (26.50 [26.00; 29.50] and 24.50 [21.75; 26.50] µm; p=0.022) and in the foveal zone (15.50 [14.00; 16.00] and 12.00 [11.00; 14.00] µm; p=0.017). Additionally, patients with MFC had a higher thickness of GCL and IPL in the fovea, inferior, nasal, and temporal parafoveal sectors. The depth of the foveal pit was significantly lower in the MFC group compared to the control group (83.0 [77.4; 101.6] and 128.0 [107.5; 147.05] µm; p=0.001). CONCLUSION: The prevalence of MFC was 4.36% (calculated per number of eyes), while the prevalence of CRM - 0.29%. The macular area in patients with MFC had increased thickness of the inner retinal layers and decreased depth of the foveal pit, suggesting potential disruption in the natural process of ganglion cell migration and apoptosis during embryogenesis.

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Mural cells are critically important for the development, maturation, and maintenance of the blood vasculature. Pericytes are predominantly observed in capillaries and venules, while vascular smooth muscle cells (VSMCs) are found in arterioles, arteries, and veins. In this study, we have investigated functional differences between human pericytes and human coronary artery smooth muscle cells (CASMCs) as a model VSMC type. We compared the ability of these two mural cells to invade three-dimensional (3D) collagen matrices, recruit to developing human endothelial cell (EC)-lined tubes in 3D matrices and induce vascular basement membrane matrix assembly around these tubes. Here, we show that pericytes selectively invade, recruit, and induce basement membrane deposition on EC tubes under defined conditions, while CASMCs fail to respond equivalently. Pericytes dramatically invade 3D collagen matrices in response to the EC-derived factors, platelet-derived growth factor (PDGF)-BB, PDGF-DD, and endothelin-1, while minimal invasion occurs with CASMCs. Furthermore, pericytes recruit to EC tube networks, and induce basement membrane deposition around assembling EC tubes (narrow and elongated tubes) when these cells are co-cultured. In contrast, CASMCs are markedly less able to perform these functions showing minimal recruitment, little to no basement membrane deposition, with wider and shorter tubes. Our new findings suggest that pericytes demonstrate much greater functional ability to invade 3D matrix environments, recruit to EC-lined tubes and induce vascular basement membrane matrix deposition in response to and in conjunction with ECs.

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Obesity is a multifactorial metabolic disorder associated with endothelial dysfunction and increased risk of cardiovascular disease. Adipose capillary adipose endothelial cells (CaECs) plays a crucial role in lipid transport and storage. Here, we investigated the mechanisms underlying CaEC-adipocyte interaction and its impact on metabolic function. Single-cell RNA sequencing (scRNAseq) revealed an enrichment of fatty acid handling machinery in CaECs from high fat diet (HFD) mice, suggesting their specialized role in lipid metabolism. Transmission electron microscopy (TEM) confirmed direct heterocellular contact between CaECs and adipocytes. To model this, we created an in vitro co-culture transwell system to model the heterocellular contact observed with TEM. Contact between ECs and adipocytes in vitro led to upregulation of fatty acid binding protein 4 in response to lipid stimulation, hinting intercellular signaling may be important between ECs and adipocytes. We mined our and others scRNAseq datasets to examine which connexins may be present in adipose capillaries and adipocytes and consistently identified connexin 43 (Cx43) in mouse and humans. Genetic deletion of endothelial Cx43 resulted in increased epididymal fat pad (eWAT) adiposity and dyslipidemia in HFD mice. Consistent with this observation, phosphorylation of Cx43 at serine 368, which closes gap junctions, was increased in HFD mice and lipid-treated ECs. Mice resistant to this post-translational modification, Cx43S368A, were placed on an HFD and were found to have reduced eWAT adiposity and improved lipid profiles. These findings suggest Cx43-mediated heterocellular communication as a possible regulatory mechanism of adipose tissue function.

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Background: Machine learning is increasingly being used to diagnose and treat various diseases, including cardiovascular diseases. Automatic image analysis can expedite tissue analysis and save time. However, using machine learning is limited among researchers due to the requirement of technical expertise. By offering extensible features through plugins and scripts, machine-learning platforms make these techniques more accessible to researchers with limited programming knowledge. The misuse of anabolic-androgenic steroids is prevalent, particularly among athletes and bodybuilders, and there is strong evidence of their detrimental effects on ventricular myocardial capillaries and muscle cells. However, most studies rely on qualitative data, which can lead to bias and limited reliability. We present a user-friendly approach using machine learning algorithms to measure the effects of exercise and anabolic-androgenic steroids on cardiac ventricular capillaries and myocytes in an experimental animal model. Method: Male Wistar rats were divided into four groups (n = 28): control, exercise-only, anabolic-androgenic steroid-alone, and exercise with anabolic-androgenic steroid. Histopathological analysis of heart tissue was conducted, with images processed and analyzed using the Trainable Weka Segmentation plugin in Fiji software. Machine learning classifiers were trained to segment capillary and myocyte nuclei structures, enabling quantitative morphological measurements. Results: Exercise significantly increased capillary density compared to other groups. However, in the exercise + anabolic-androgenic steroid group, steroid use counteracted this effect. Anabolic-androgenic steroid alone did not significantly impact capillary density compared to the control group. Additionally, the exercise group had a significantly shorter intercapillary distance than all other groups. Again, using steroids in the exercise + anabolic-androgenic steroid group diminished this positive effect. Conclusion: Despite limited programming skills, researchers can use artificial intelligence techniques to investigate the adverse effects of anabolic steroids on the heart's vascular network and muscle cells. By employing accessible tools like machine learning algorithms and image processing software, histopathological images of capillary and myocyte structures in heart tissues can be analyzed.

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BACKGROUND: Leprosy, a chronic infectious disease, is associated with various nail changes. Its etiopathogenesis is multifaceted, with microvascular damage being crucial. Nail fold capillaroscopy (NFC) emerges as a novel tool for detecting early vascular deficits in leprosy. The study aimed to assess and provide a complete clinical characterization of NFC changes in leprosy patients. METHODS: It is an observational cross-sectional study, done over a period of 1.5 year (January 2021 to august 2022) in a tertiary care hospital, encompassing 60 patients diagnosed with leprosy (18-60 years). After obtaining informed consent; detailed history, complete cutaneous and neurological examinations were conducted. All fingernails and toenails were examined for clinical changes. Subsequently, onychoscopy was performed using USB type of video-dermatoscope (Model AM7115MZT Dino-lite), a non-invasive tool. This was followed by NFC which was done for all fingernails and images were recorded by single operator, which were then assessed for quantitative and qualitive changes and statistical analysis was conducted using SPSS v20, with mean capillary density compared using Student's t-test, morphological change frequencies assessed by proportions, and group comparisons made using Chi-square or Fischer exact tests, with a significance threshold of p < 0.05. RESULTS: Among the 60 patients, 39 were in the lepromatous group, which included both borderline lepromatous (BL) and lepromatous leprosy (LL) patients, and 17 were in the tuberculoid group, which included borderline tuberculoid (BT) leprosy patients; 23.3 % had Type 1 reactions, and 18.3 % had Type 2 reactions. Nail fold capillaroscopy (NFC) showed microvasculature changes in 93.3 % of patients. The average capillary density was 6.8 ± 1.5 capillaries per mm, with the lepromatous group having a lower density (6.5 ± 1.09) compared to the tuberculoid group (7.0 ± 0.86). The most common NFC changes in the tuberculoid group were tortuous capillaries (70 %), capillary dropouts, and dilated capillaries (both 64.7 %). In the lepromatous group, capillary dropouts (82 %) were most frequent, followed by tortuous (69 %), receding (69 %), and dilated capillaries (66 %). A dilated and prominent subpapillary plexus was more common in the lepromatous group (35 %, p = 0.04). Patients with trophic changes in the lepromatous group had more capillary dropouts and bizarre capillaries. Capillary dropouts, dilated capillaries, and visible subpapillary venous plexus were more prevalent in patients with Type 2 reactions. CONCLUSION: NFC changes are prevalent in both tuberculoid and lepromatous leprosy, which may be an indicator of peripheral vascular compromise and trophic changes, especially in lepromatous leprosy. NFC can be an auxiliary tool for detecting microvascular abnormalities in leprosy patients.

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INTRODUCTION: Botulinum toxin A (BoTA) is a neurotoxin formed by Clostridium botulinum, with a broad medical application spectrum. While the primary effect of BoTA is on the muscles, the effects of BoTA in other systems including the blood vasculature have already been examined, revealing unexpected actions. However, no studies exist to the best of our knowledge regarding the potential effects of BoTA on the lymphatic vascular system, possessing a critical role in health and disease. Isolated human lymphatic endothelial cells (LECs) were cultured in dedicated in vitro culture systems. The analysis including imaging and cell culture approaches as well as molecular biology techniques is performed to examine the LEC alterations occurring upon exposure to different concentrations of BoTA. MATERIALS AND METHODS: Human LECs were cultured and expanded on collagen-coated petri dishes using endothelial basal medium and the commercial product Botox from Allergan as used for all our experiments. Harvested cells were used in various in vitro functional tests to assess the morphologic and functional properties of the BoTA-treated LECs. Gene expression analysis was performed to assess the most important lymphatic system-related genes and pathways. RESULTS: Concentrations of 1, 5 or 10 U of BoTA did not demonstrate a significant effect regarding the proliferation and migration capacity of the LECs versus untreated controls. Interestingly, even the smallest BoTA dose was found to significantly decrease the cord-like-structure formation capacity of the seeded LECs. Gene expression analysis was used to underpin possible molecular alterations, suggesting no significant effect of BoTA in the modification of gene expression versus the starvation medium control. CONCLUSION: LECs appear largely unaffected to BoTA treatment, with an isolated effect on the cord-like-structure formation capacity. Further work needs to assess the effect of BoTA on the smooth-muscle-cell-covered collecting lymphatic vessels and the possible aesthetic implications of such an effect, due to edema formation. LEVEL OF EVIDENCE V: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

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Introduction: Traumatic brain injury to thalamo-cortical pathways is associated with posttraumatic morbidity. Diffuse mechanical forces to white matter tracts and deep grey matter regions induce an inflammatory response and vascular damage resulting in progressive neurodegeneration. Pro-inflammatory cytokines, including interleukin-1ß (IL-1ß), may contribute to the link between inflammation and the injured capillary network after TBI. This study investigates whether IL-1ß is a key contributor to capillary alterations and changes in pericyte coverage in the thalamus and cortex after TBI. Methods: Animals were subjected to central fluid percussion injury (cFPI), a model of TBI causing widespread axonal and vascular pathology, or sham injury and randomized to receive a neutralizing anti-IL-1ß or a control, anti-cyclosporin A antibody, at 30 min post-injury. Capillary length and pericyte coverage of cortex and thalamus were analyzed by immunohistochemistry at 2- and 7-days post-injury. Results and Conclusion: Our results show that early post-injury attenuation of IL-1ß dependent inflammatory signaling prevents capillary damage by increasing pericyte coverage in the thalamus.

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Background: Capillary ultrastructure in human skeletal muscles is dynamic and prone to alterations in response to many stimuli, e.g., systemic pathologies such as diabetes mellitus and arterial hypertension. Using transmission electron microscopy (TEM) images, several studies have been conducted to quantify the capillary ultrastructure by means of morphometry. Deep learning techniques like convolutional neural networks (CNNs) are utilized to extract data-driven characteristics and to recognize patterns. Hence, the aim of this study was to train a CNN to identify morphometric patterns that differ between capillaries in muscle biopsies of healthy participants and patients with systemic pathologies for the purpose of hypothesis generation. Methods: In this retrospective study we used 1810 electron micrographs from human skeletal muscle capillaries derived from 70 study participants which were classified as "healthy" controls or "patients" in dependence of the absence or presence of a documented history of diabetes mellitus, arterial hypertension or peripheral arterial disease. Using these micrographs, a pre-trained open-access CNN (ResNet101) was trained to discriminate between micrographs of capillaries of the two groups. The CNN with the highest diagnostic accuracies during training were subsequently compared with manual quantitative analysis of the capillary ultrastructure to distinguish between "healthy" controls and patients. Results: Using classification into controls or patients as allocation reference, receiver-operating-characteristics (ROC)-analysis of manually obtained BM thickness showed the best diagnostic accuracy of all morphometric indicators (area under the ROC-curve (AUC): 0.657 ± 0.050). The best performing CNN demonstrated a diagnostic accuracy of 79% (sensitivity 93%, specificity 92%). DeLong-Test of the ROC-curves showed a significant difference (p < 0.001) between the AUC of the best performing CNN and the BM thickness. The underlying morphology responsible for the network prediction focuses mainly on debridement of pericytes. Conclusion: The hypothesis-generating approach using pretrained CNN distinguishes between capillaries depicted on electron micrographs of "healthy" controls and participants with a systemic pathology more accurately than by commonly used morphometric analysis.

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ARISE (Aneurysm/AVM/cSDH Roundtable Discussion With Industry and Stroke Experts) organized a one-and-a-half day meeting and workshop and brought together representatives from academia, industry, and government to discuss the most promising approaches to improve outcomes for patients with chronic subdural hematoma (cSDH). The emerging role of middle meningeal artery embolization in clinical practice and the design of current and potential future trials were the primary focuses of discussion. Existing evidence for imaging, indications, agents, and techniques was reviewed, and areas of priority for study and key questions surrounding the development of new and existing treatments for cSDH were identified. Multiple randomized, controlled trials have met their primary efficacy end points, providing high-level evidence that middle meningeal artery embolization is a potent adjunctive therapy to the standard (surgical and nonsurgical) management of neurologically stable cSDH patients in terms of reducing rates of disease recurrence. Pooled data analyses following the formal conclusion and publication of these trials will form a robust foundation upon which guidelines can be strengthened for cSDH treatment modalities and optimal patient selection, as well as delineate future lines of investigation.

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BACKGROUND: Macular edema (ME) results from hyperpermeability of retinal vessels, leading to chronic extravasation of plasma components into the retina and hence potentially severe visual acuity loss. Current standard of care consists in using intravitreal injections (IVI), which results in a significant medical and economic burden. During diabetic retinopathy (DR) or retinal vein occlusion (RVO), it has recently been shown that focal vascular anomalies (capillary macro-aneurysms, also termed TelCaps) for telangiectatic capillaries may play a central role in the onset, early recurrence, and/or persistence of ME. Since targeted photocoagulation of TelCaps may improve vision, identification, and photocoagulation of TelCaps, it may represent a way to improve management of ME. OBJECTIVE: The Targeted Laser in (Diabetic) Macular Edema (TalaDME) study aims to evaluate whether ICG-guided targeted laser (IGTL), in association with standard of care by IVI, allows reducing the number of injections during the first year of treatment compared with IVI only, while remaining non-inferior for visual acuity. METHODS: TalaDME is a French, multicentric, two-arms, randomized, sham laser-controlled, double-masked trial evaluating the effect of photocoagulation of TelCaps combined to IVI in patients with ME associated with TelCaps. Patients with vision loss related to center involved ME secondary to RVO or DR and presenting TelCaps are eligible. Two hundred and seventy eyes of 270 patients are randomized in a 1:1 ratio to standard care, i.e., IVI of anti-VEGF solely (control group) or combined with IGTL therapy (experimental group). Stratification is done on the cause of ME (i.e., RVO versus diabetes). Anti-VEGF IVI are administered to both groups monthly for 3 months (loading dose) and then with a pro re nata regimen with a monthly follow-up for 12 months. The primary endpoint will be the number of IVI and the change in visual acuity from baseline to 12 months. Secondary endpoints will be the changes in central macular thickness, impact on quality of life, cost of treatment, and incremental cost-utility ratio in each groups. KEY SAFETY: Rare but severe AE linked to the use of IVI and laser, and previously described, are expected. In the sham group, rescue laser photocoagulation may be administered by the unmasked investigator if deemed necessary at month 3. DISCUSSION: The best management of ME associated with TelCaps is debated, and there have been no randomized study designed to answer this question. Given the fact that TelCaps may affect 30 to 60% of patients with chronic ME due to DR or RVO, a large number of patients could benefit from a specific management of TelCaps. TalaDME aims to establish the clinical and medico-economic benefits of additional targeted laser. The results of TalaDME may raise new recommendations for managing ME and impact healthcare costs. TRIAL REGISTRATION: EudraCT: 2018-A00800-55/ NCT03751501. Registration date: Nov. 23, 2018.

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Introduction: Histological data on muscle fiber size and proportion in (very) young typically developing (TD) children is not well documented and data on capillarization and satellite cell content are also lacking. Aims: This study investigated the microscopic properties of the medial gastrocnemius muscle in growing TD children, grouped according to age and gender to provide normal reference values in healthy children. Methods: Microbiopsies of the medial gastrocnemius (MG) muscle were collected in 46 TD boys and girls aged 2-10 years subdivided into 4 age groups (2-4, 4-6, 6-8 and 8-10 years). Sections were immunostained to assess fiber type cross-sectional area (fCSA) and proportion, the number of satellite cells (SC), capillary to fiber ratio (C/F), capillary density for type I and II fiber (CFD), capillary domain, capillary-to-fiber perimeter exchange index (CFPE) and heterogeneity index. fCSA was normalized to fibula length2 and the coefficient of variation (CV) was calculated to reflect fCSA intrasubject variability. Results: Absolute fCSA of all fibers increased with age (r = 0.72, p < 0.001) but more in boys (+112%, p < 0.05) than in girls (+48%, p > 0.05) Normalized fCSA, CV and fiber proportion did not differ between age groups and gender. C/F was strongly correlated with age in boys (r = 0.83, p < 0.001), and to a lesser extent in girls (r = 0.37, p = 0.115), while other capillary parameters as well as the number of SC remained stable with increasing age in boys and girls. Discussion: This study provides reference values of histological measures in MG according to age in normally growing boys and girls. These data may be used as a reference to determine disease impact and efficacy of therapeutic approach on the muscle.

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The etiology of primary pulmonary angiosarcoma is still unknown. Here we report a case of primary pulmonary angiosarcoma originated from a tuberculous scar and presented as aggressive deterioration with uncontrolled bleeding from capillaries with angiodysplasia.

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Changes in the structure and function of nailfold capillaries may be indicators of numerous diseases. Noninvasive diagnostic tools are commonly used for the extraction of morphological information from segmented nailfold capillaries to study physiological and pathological changes therein. However, current segmentation methods for nailfold capillaries cannot accurately separate capillaries from the background, resulting in issues such as unclear segmentation boundaries. Therefore, improving the accuracy of nailfold capillary segmentation is necessary to facilitate more efficient clinical diagnosis and research. Herein, we propose a nailfold capillary image segmentation method based on a U2-Net backbone network combined with a Transformer structure. This method integrates the U2-Net and Transformer networks to establish a decoder-encoder network, which inserts Transformer layers into the nested two-layer U-shaped architecture of the U2-Net. This structure effectively extracts multiscale features within stages and aggregates multilevel features across stages to generate high-resolution feature maps. The experimental results demonstrate an overall accuracy of 98.23 %, a Dice coefficient of 88.56 %, and an IoU of 80.41 % compared to the ground truth. Furthermore, our proposed method improves the overall accuracy by approximately 2 %, 3 %, and 5 % compared to the original U2-Net, Res-Unet, and U-Net, respectively. These results indicate that the Transformer-U2Net network performs well in nailfold capillary image segmentation and provides more detailed and accurate information on the segmented nailfold capillary structure, which may aid clinicians in the more precise diagnosis and treatment of nailfold capillary-related diseases.

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The integrity of the blood-brain barrier (BBB) is essential for the normal functioning of the central nervous system (CNS). Isolated brain capillaries are essential for analyzing changes in protein and gene expression at the BBB under physiological and pathological conditions. The standard methods for isolating brain capillaries require the use of at least one or more mouse brains in order to obtain sufficient quantity and purity of brain capillaries. Here, we describe an optimized protocol for isolating and purifying capillaries from tiny amounts of mouse cerebral cortex using manual homogenization, density gradient centrifugation, and filtration while preserving the structural integrity and functional activity of microvessel fragments. Western blotting showed that proteins expressed at the BBB were enriched in mouse brain capillaries isolated by the optimized method compared to cerebral cortex protein homogenates. This approach can be used for the analysis of a variety of rare mouse genetic models and can also help the investigators to understand regional differences in susceptibility to pathological phenomena such as ischemia and traumatic brain injury. This will allow the investigators to better understand the physiology and pathology of the BBB.

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Ion-selective membrane has broad application in various fields, while the present solution-processed techniques can only prepare uniform membrane with microscale thickness. Herein, a high-quality polymer membrane with nanoscale thickness and uniformity is precisely prepared by controlling solution spreading and solvent evaporation stability/rate. With the arrayed capillaries, the stable spreading of polymer solution with volume of microliter induces the formation of solution film with micrometers thickness. Moreover, the fast increase of solution dynamic viscosity during solvent evaporation inhibits nonuniform Marangoni flow and capillary flow in solution film. Consequently, the uniform Nafion-Li membranes with ∼200 nm thickness are prepared, while their Li+ conductivity is 2 orders of magnitude higher than that of commercially Nafion-117 membrane. Taking lithium-sulfur battery as a model device, the cells (capacities of 8-10 mAh cm-2) can stably operate for 150 cycles at a S loading of 12 mg cm-2 and an electrolyte/sulfur ratio of ∼7.