3,578 research outputs found

    Leaf-inspired microcontact printing vascular patterns.

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    The vascularization of tissue grafts is critical for maintaining viability of the cells within a transplanted graft. A number of strategies are currently being investigated including very promising microfluidics systems. Here, we explored the potential for generating a vasculature-patterned endothelial cells that could be integrated into distinct layers between sheets of primary cells. Bioinspired from the leaf veins, we generated a reverse mold with a fractal vascular-branching pattern that models the unique spatial arrangement over multiple length scales that precisely mimic branching vasculature. By coating the reverse mold with 50 μg ml-1 of fibronectin and stamping enabled selective adhesion of the human umbilical vein endothelial cells (HUVECs) to the patterned adhesive matrix, we show that a vascular-branching pattern can be transferred by microcontact printing. Moreover, this pattern can be maintained and transferred to a 3D hydrogel matrix and remains stable for up to 4 d. After 4 d, HUVECs can be observed migrating and sprouting into Matrigel. These printed vascular branching patterns, especially after transfer to 3D hydrogels, provide a viable alternative strategy to the prevascularization of complex tissues

    The Short-a System of New York City English: An Update

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    This paper reports on the current status of the short-a system in New York City English (NYCE), traditionally characterized as a phonemic split conditioned by the following phonological environment and a complex set of additional constraints (Labov 2007, Labov, Ash, and Boberg 2006). We provide apparent-time evidence from twelve white native New Yorkers of three age groups that the complex short-a split is changing over time, such that the system is losing its complex conditioning among our young white speakers. These results raise questions concerning the continuing characterization of NYCE short-a as phonemic. Additionally, we demonstrate that young native New Yorkers of ethnic minority backgrounds (Chinese, Puerto Rican, and African American) who speak English natively do not produce the traditional NYCE split, but instead produce a nasal tensing system (Labov 2007). In addition to providing current results suggesting change in white NYCE, this study contributes to the growing literature in sociolinguistics regarding ethnic minority speakers and their production of regional dialect features

    Vendor-hosted versus Self-hosted Implementation of Open-Source Software at GLAM Institutions

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    This study investigates how those with input in software purchasing decisions choose to host open-source software at their galleries, libraries, archives, and museums (GLAM institutions). A survey was distributed to several GLAM-specific open-source community listservs to collect data on the various factors considered and overlooked. Responses suggest that decisions are made based on constraints and not preference. The level of technical expertise at the participant’s institution greatly affected how funds are used. Analysis also shows that participants underestimate the total costs of maintaining open-source software and overestimate the vendor/consortium’s ability to customize software.Master of Science in Information Scienc

    Glutamate and Dysconnection in the Salience Network: Neurochemical, Effective Connectivity, and Computational Evidence in Schizophrenia

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    Background: Functional dysconnection in schizophrenia is underwritten by a pathophysiology of the glutamate neurotransmission that affects the excitation-inhibition balance in key nodes of the salience network. Physiologically, this manifests as aberrant effective connectivity in intrinsic connections involving inhibitory interneurons. In computational terms, this produces a pathology of evidence accumulation and ensuing inference in the brain. Finally, the pathophysiology and aberrant inference would partially account for the psychopathology of schizophrenia as measured in terms of symptoms and signs. We refer to this formulation as the 3-level hypothesis. Methods: We tested the hypothesis in core nodes of the salience network (the dorsal anterior cingulate cortex [dACC] and the anterior insula) of 20 patients with first-episode psychosis and 20 healthy control subjects. We established 3-way correlations between the magnetic resonance spectroscopy measures of glutamate, effective connectivity of resting-state functional magnetic resonance imaging, and correlations between measures of this connectivity and estimates of precision (inherent in evidence accumulation in the Stroop task) and psychopathology. Results: Glutamate concentration in the dACC was associated with higher and lower inhibitory connectivity in the dACC and in the anterior insula, respectively. Crucially, glutamate concentration correlated negatively with the inhibitory influence on the excitatory neuronal population in the dACC of subjects with first-episode psychosis. Furthermore, aberrant computational parameters of the Stroop task performance were associated with aberrant inhibitory connections. Finally, the strength of connections from the dACC to the anterior insula correlated negatively with severity of social withdrawal. Conclusions: These findings support a link between glutamate-mediated cortical disinhibition, effective-connectivity deficits, and computational performance in psychosis

    Idd9.2 and Idd9.3 Protective Alleles Function in CD4+ T-Cells and Nonlymphoid Cells to Prevent Expansion of Pathogenic Islet-Specific CD8+ T-Cells

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    OBJECTIVE - Multiple type 1 diabetes susceptibility genes have now been identified in both humans and mice, yet mechanistic understanding of how they impact disease pathogenesis is still minimal. We have sought to dissect the cellular basis for how the highly protective mouse Idd9 region limits the expansion of autoreactive CD8 T-cells, a key cell type in destruction of the islets. RESEARCH DESIGN AND METHODS - We assess the endogenous CD8 T-cell repertoire for reactivity to the islet antigen glucose-6-phosphatase-related protein (IGRP). Through the use of adoptively transferred T-cells, bone marrow chimeras, and reconstituted severe combined immunodeficient mice, we identify the protective cell types involved. RESULTS - IGRP-specific CD8 T-cells are present at low frequency in the insulitic lesions of Idd9 mice and could not be recalled in the periphery by viral expansion. We show that Idd9 genes act extrinsically to the CD8 T-cell to prevent the massive expansion of pathogenic effectors near the time of disease onset that occurs in NOD mice. The subregions Idd9.2 and Idd9.3 mediated this effect. Interestingly, the Idd9.1 region, which provides significant protection from disease, did not prevent the expansion of autoreactive CD8 T-cells. Expression of Idd9 genes was required by both CD4 T-cells and a nonlymphoid cell to induce optimal tolerance. CONCLUSIONS - Idd9 protective alleles are associated with reduced expansion of IGRP-specific CD8 T-cells. Intrinsic expression of protective Idd9 alleles in CD4 T-cells and nonlymphoid cells is required to achieve an optimal level of tolerance. Protective alleles in the Idd9.2 congenic subregion are required for the maximal reduction of islet-specific CD8 T-cells

    Technical efficiency and production risk of rice farms under Anchor Borrowers programme in Kebbi State, Nigeria

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    This study estimates technical efficiency and production risk of rice farms under Anchor Borrowers Programme (ABP) in Kebbi State, Nigeria. The study employed Stochastic Frontier Production (SFA) with flexible risk specifications to a sample of 231 rice producers surveyed in 2016 production season. The findings shows that seed, fertilizer, agrochemicals and labour inputs influenced rice output positively. The production technology characterizing rice farms in the study area exhibit increasing returns to scale. Fertilizer and agrochemicals are estimated to decrease variance of the value of output while seed and labour are estimated to increase the variance of the value of output. This implies that a risk-averse farmer will use more of fertilizer and agrochemicals and less of seed and labour than a risk neutral farmer. The mean technical efficiency estimates was 85.3 percent. Several characteristics of the farmers such as education, farming experience, extension contact, land cultivation technique and planting technique significantly decrease technical inefficiency of the farmers. The study concludes that, on the average 14.7 percent of potential output is lost due to technical inefficiency and production risk in inputs and recommends the use of best farm practice to produce rice efficiently. Policy option should also consider the incorporation of production risk in technical efficiency analysis if the inputs are non-neutral in risk

    Diagnosis, Prognosis, Management, Treatment, Research and Advances in Canine Dilated Cardiomyopathy

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    Dilated cardiomyopathy involves enlargement of the ventricular chamber and systolic dysfunction. The reduction in quality of life and increased levels of congestive heart failure, combined with the high diagnosis rate within the canine population, highlights the need for research into this disorder. This chapter looks at prevention, diagnosis, prognosis, and treatment of dilated cardiomyopathy. It details the disease pathology and physiology through to present clinical practices and studies to support prevention and treatment. This chapter also looks at the research being undertaken to further understand cardiomyopathies in dogs and develop new interventions. This ranges from fatty acids profiles to genetics and even personalized medicine and comparisons with human cardiomyopathy
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