5,828 research outputs found

    Investigation of electrical properties for cantilever-based piezoelectric energy harvester

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    In the present era, the renewable sources of energy, e.g., piezoelectric materials are in great demand. They play a vital role in the field of micro-electromechanical systems, e.g., sensors and actuators. The cantilever-based piezoelectric energy harvesters are very popular because of their high performance and utilization. In this research-work, an energy harvester model based on a cantilever beam with bimorph PZT-5A, having a substrate layer of structural steel, was presented. The proposed energy scavenging system, designed in COMSOL Multiphysics, was applied to analyze the electrical output as a function of excitation frequencies, load resistances and accelerations. Analytical modeling was employed to measure the output voltage and power under pre-defined conditions of acceleration and load resistance. Experimentation was also performed to determine the relationship between independent and output parameters. Energy harvester is capable of producing the maximum power of 1.16 mW at a resonant frequency of 71 Hz under 1g acceleration, having load resistance of 12 k Omega. It was observed that acceleration and output power are directly proportional to each other. Moreover, the investigation conveys that the experimental results are in good agreement with the numerical results. The maximum error obtained between the experimental and numerical investigation was found to equal 4.3%

    Müller glia activation in response to inherited retinal degeneration is highly varied and disease-specific

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    Despite different aetiologies, most inherited retinal disorders culminate in photoreceptor loss, which induces concomitant changes in the neural retina, one of the most striking being reactive gliosis by Müller cells. It is typically assumed that photoreceptor loss leads to an upregulation of glial fibrilliary acidic protein (Gfap) and other intermediate filament proteins, together with other gliosis-related changes, including loss of integrity of the outer limiting membrane (OLM) and deposition of proteoglycans. However, this is based on a mix of both injury-induced and genetic causes of photoreceptor loss. There are very few longitudinal studies of gliosis in the retina and none comparing these changes across models over time. Here, we present a comprehensive spatiotemporal assessment of features of gliosis in the degenerating murine retina that involves Müller glia. Specifically, we assessed Gfap, vimentin and chondroitin sulphate proteoglycan (CSPG) levels and outer limiting membrane (OLM) integrity over time in four murine models of inherited photoreceptor degeneration that encompass a range of disease severities (Crb1rd8/rd8, Prph2+/Δ307, Rho-/-, Pde6brd1/rd1). These features underwent very different changes, depending upon the disease-causing mutation, and that these changes are not correlated with disease severity. Intermediate filament expression did indeed increase with disease progression in Crb1rd8/rd8 and Prph2+/Δ307, but decreased in the Prph2+/Δ307 and Pde6brd1/rd1 models. CSPG deposition usually, but not always, followed the trends in intermediate filament expression. The OLM adherens junctions underwent significant remodelling in all models, but with differences in the composition of the resulting junctions; in Rho-/- mice, the adherens junctions maintained the typical rod-Müller glia interactions, while in the Pde6brd1/rd1 model they formed predominantly between Müller cells in late stage of degeneration. Together, these results show that gliosis and its associated processes are variable and disease-dependent

    Assessment of physicochemical performance of draw compounds for desalination using multi-criteria analysis

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    The development of draw compounds for forward osmosis (FO) has been an active area of research. While a few studies have considered draw solutes for FO desalination, these are rarely presented with consistent units for objective performance comparison. To rectify this lack of knowledge, this study objectively compares draw solutes using a multi-criteria analysis (MCA) across a range of physicochemical properties (in consistent units), along with their flux performance when integrated with FO membranes. This analysis reveals that Ionic liquids (IL) have favorable physicochemical characteristics and generally higher flux performance in both nonresponsive and thermally responsive draw solute classes. In particular, magnesium chloride was found to be the optimal non-responsive draw solute. In addition, a diammonium cation-based iodide salt and an oligomer of choline chloride and an itaconic acid mixture were found to achieve the highest water flux of ~15LMH when treating seawater level salinity solutions within thermally responsive draw compounds. The MCA also revealed that hydrogels—particularly those based on poly(N-isopropylacrylamide) (PNIPAM)—are promising because they have the best dewatering capability but suffers from low water flux. Overall, we conclude that IL draw solutions and PNIPAM-based hydrogels represent some of the most promising FO draw compounds for future research

    Regeneration of Sudanese maize inbred lines and open pollinated varieties

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    Eight maize inbred lines and three open pollinated varieties from Sudan were evaluated for their response to tissue culture. Immature embryos obtained 16 days after pollination were used as explants for callus induction. Calli were induced on LS medium supplemented with 2 mg/L 2,4-dichlorophenoxyacetic acid. Callus induction capacity was highest in inbred lines IL3, IL15 and IL1. The Varieties Hudiba-2 and Hudiba-1 were not statistically different (p >0.05) in callus induction. Thecapacity for embryogenic callus formation was highest in inbred line IL3 followed by IL1 and IL38 and in varieties Hudiba-2 and Hudiba-1. Inbred lines IL16, IL42, IL43 and IL28 had the lowest embryogeniccallus formation capacity. Plant regenerating genotypes were IL3, IL38, IL15, IL1, Hudiba-2 and Mojtamaa-45. Inbred line IL3 was the most regenerable genotype with a shoot formation frequency of 76% averaging 6 shoots per callus. The highest regenerating variety was Mojtamaa-45, which averaged 5 shoots per callus

    Faculty Members and Students’ Opinion about Quality of Services Provided by the Central Library of Kerman University of Medical Sciences

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    Background & Objective : Libraries are among main parts of universities as libraries of high quality lead to improvement in education and research within universities and the society. Assessing quality of services in educational systems is important to improve quality of provided services. This study was conducted to assess the quality of services provided by the central library of Kerman University of Medical Sciences from the faculty members and students’ point of view . Methods : In this study, 200 faculty members and students of Kerman University of Medical Sciences were chosen using stratified random sampling. The data was collected using LibQUAL+TM standard questionnaire after its validity and reliability were confirmed Results : Our findings showed that the mean score of general satisfaction of the central library’s provided services was 6.13 out of 9. Among the three aspects of library service quality, information control was the most satisfactory factor (5.98) which was followed by efficacy of services (5.96) and the library’s atmosphere (5.89). Faculty members were more satisfied with the central library’s provided services in all aspects compared to students, although this difference was not significant. The most frequent referral to the central library and using references was once a month. Conclusion : Although the findings of this study were suggestive of faculty members and students’ relative satisfaction of provided services, improving quality of services necessitates better and more organized planning. Improvement of library service quality can lead to promoting faculty members and students’ scientific level in universities of medical sciences, medical knowledge, and medical education . Keywords: Service Quality, LibQUAL+TM survey, Faculty member, Student

    A comprehensive atlas of Aggrecan, Versican, Neurocan and Phosphacan expression across time in wildtype retina and in retinal degeneration

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    As photoreceptor cells die during retinal degeneration, the surrounding microenvironment undergoes significant changes that are increasingly recognized to play a prominent role in determining the efficacy of therapeutic interventions. Chondroitin Sulphate Proteoglycans (CSPGs) are a major component of the extracellular matrix that have been shown to inhibit neuronal regrowth and regeneration in the brain and spinal cord, but comparatively little is known about their expression in retinal degeneration. Here we provide a comprehensive atlas of the expression patterns of four individual CSPGs in three models of inherited retinal degeneration and wildtype mice. In wildtype mice, Aggrecan presented a biphasic expression, while Neurocan and Phosphacan expression declined dramatically with time and Versican expression remained broadly constant. In degeneration, Aggrecan expression increased markedly in Aipl1-/- and Pde6brd1/rd1, while Versican showed regional increases in the periphery of Rho-/- mice. Conversely, Neurocan and Phosphacan broadly decrease with time in all models. Our data reveal significant heterogeneity in the expression of individual CSPGs. Moreover, there are striking differences in the expression patterns of specific CSPGs in the diseased retina, compared with those reported following injury elsewhere in the CNS. Better understanding of the distinct distributions of individual CSPGs will contribute to creating more permissive microenvironments for neuro-regeneration and repair

    Optimal multi-block mesh generation for CFD

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    An assessment of various automatic block topology generation techniques for creating structured meshes has been performed in the first part of the paper. The objective is to find out optimal blocking methods for generating meshes suitable for flow simulations. The comparison has been carried out using an adjoint based error analysis of the meshes generated by these block topologies. Different objective functions and numerical schemes have been used for this assessment. It is found that, in general, the medial axis based approaches provide optimal blocking and yields better accuracy in computing the functional of interest. This is because the medial axis based methods produce meshes which have better flow alignment specially in case of internal flows. In the second part of the paper, the adjoint based error indicator has been used to adapt the block topology in the regions of large error.Rolls Royce, plc TSB SILOET II TS/L00691X/

    Detection of non-melanoma skin cancer by in vivo fluorescence imaging with fluorocoxib A.

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    Non-melanoma skin cancer (NMSC) is the most common form of cancer in the US and its incidence is increasing. The current standard of care is visual inspection by physicians and/or dermatologists, followed by skin biopsy and pathologic confirmation. We have investigated the use of in vivo fluorescence imaging using fluorocoxib A as a molecular probe for early detection and assessment of skin tumors in mouse models of NMSC. Fluorocoxib A targets the cyclooxygenase-2 (COX-2) enzyme that is preferentially expressed by inflamed and tumor tissue, and therefore has potential to be an effective broadly active molecular biomarker for cancer detection. We tested the sensitivity of fluorocoxib A in a BCC allograft SCID hairless mouse model using a wide-field fluorescence imaging system. Subcutaneous allografts comprised of 1000 BCC cells were detectable above background. These BCC allograft mice were imaged over time and a linear correlation (R(2) = 0.8) between tumor volume and fluorocoxib A signal levels was observed. We also tested fluorocoxib A in a genetically engineered spontaneous BCC mouse model (Ptch1(+/-) K14-Cre-ER2 p53(fl/fl)), where sequential imaging of the same animals over time demonstrated that early, microscopic lesions (100 μm size) developed into visible macroscopic tumor masses over 11 to 17 days. Overall, for macroscopic tumors, the sensitivity was 88% and the specificity was 100%. For microscopic tumors, the sensitivity was 85% and specificity was 56%. These results demonstrate the potential of fluorocoxib A as an in vivo imaging agent for early detection, margin delineation and guided biopsies of NMSCs

    Harnessing the Potential of Human Pluripotent Stem Cells and Gene Editing for the Treatment of Retinal Degeneration

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    PURPOSE OF REVIEW: A major cause of visual disorders is dysfunction and/or loss of the light-sensitive cells of the retina, the photoreceptors. To develop better treatments for patients, we need to understand how inherited retinal disease mutations result in the dysfunction of photoreceptors. New advances in the field of stem cell and gene editing research offer novel ways to model retinal dystrophies in vitro and present opportunities to translate basic biological insights into therapies. This brief review will discuss some of the issues that should be taken into account when carrying out disease modelling and gene editing of retinal cells. We will discuss (i) the use of human induced pluripotent stem cells (iPSCs) for disease modelling and cell therapy; (ii) the importance of using isogenic iPSC lines as controls; (iii) CRISPR/Cas9 gene editing of iPSCs; and (iv) in vivo gene editing using AAV vectors. RECENT FINDINGS: Ground-breaking advances in differentiation of iPSCs into retinal organoids and methods to derive mature light sensitive photoreceptors from iPSCs. Furthermore, single AAV systems for in vivo gene editing have been developed which makes retinal in vivo gene editing therapy a real prospect. SUMMARY: Genome editing is becoming a valuable tool for disease modelling and in vivo gene editing in the retina
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