40 research outputs found

    Spectroscopic evidence for a surface layer in CuInSe2:Cu deficiency

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    The near-surface region of thin-film polycrystalline (PX) CuIn1-xGaxSe2 (CIGS) is considered important because it is the region where the electrical junction forms in a CIGS photovoltaic device. Spectroscopic ellipsometry measurements of polycrystalline CuInSe2 films reveal that there is a thin layer at the surface which has different optical and electronic properties from those of the bulk film. This surface layer of thin-film CIGS has a larger band gap and greater spin-orbit interaction energy than the bulk film. These properties indicate that the surface layer is more Cu deficient than the bulk in the nearly stoichiometric thin-film PX-CIGS used in photovoltaic devices. This work provides an insight into the importance of surface layer engineering for photovoltaic device design. (C) 2007 American Institute of Physics

    Barriers to gene flow in the deepest ocean ecosystems: evidence from global population genomics of a cosmopolitan amphipod

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    The deepest marine ecosystem, the hadal zone, hosts endemic biodiversity resulting from geographic isolation and environmental selection pressures. However, the pan-ocean distribution of some fauna challenges the concept that the hadal zone is a series of isolated island-like habitats. Whether this remains true at the population genomic level is untested. We investigated phylogeographic patterns of the amphipod, Bathycallisoma schellenbergi, from 12 hadal features across the Pacific, Atlantic, Indian, and Southern oceans and analyzed genome-wide single-nucleotide polymorphism markers and two mitochondrial regions. Despite a cosmopolitan distribution, populations were highly restricted to individual features with only limited gene flow between topographically connected features. This lack of connectivity suggests that populations are on separate evolutionary trajectories, with evidence of potential cryptic speciation at the Atacama Trench. Together, this global study demonstrates that the shallower ocean floor separating hadal features poses strong barriers to dispersal, driving genetic isolation and creating pockets of diversity to conserve

    Lower Urinary Tract Symptoms in Depression: A Review

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    Lower Urinary Tract Symptoms (LUTS) are frequently present in the general population as patients age with approximately a third of individuals experiencing LUTS during their lifetime. LUTS can be further defined as having any of the following symptoms: urinary hesitancy, straining, nocturia, increased urination frequency, and dysuria. LUTS has the potential for patients to contribute their symptoms to what can normally occur as we age. This can lead to a decrease in patients seeking care and could negatively impact patients’ health-related quality of life (HRQL). In conjunction with LUTS, we obtained from our analysis that LUTS and depression are closely related and worsening depressive symptoms may increase the severity of LUTS. We also discerned three categories of factors that can yield major depression namely adversity, internalizing, and externalizing factors. Within these categories, trauma, social support, genetic factors, and minimal education appeared to increase the risk of depression in patients. With the recent increase in mental health awareness and more access to mental health care amid the COVID-19 Pandemic, further screening, and collaboration between providers to treat both urological and psychiatric symptoms could improve patient outcomes. It is important for providers to have an increased understanding of the mental and physical impact both LUTS and depression can have on patients’ wellbeing. This has the potential to help patients be more open about their symptoms with the aim of better addressing LUTS and depression to positively impact their HRQL

    Pattern selection in the absolutely unstable regime as a nonlinear eigenvalue problem: Taylor vortices in axial flow

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    A unique pattern selection in the absolutely unstable regime of a driven, nonlinear, open-flow system is analyzed: The spatiotemporal structures of rotationally symmetric vortices that propagate downstream in the annulus of the rotating Taylor-Couette system due to an externally imposed axial through-flow are investigated for two different axial boundary conditions at the in- and outlet. Unlike the stationary patterns in systems without through-flow the spatiotemporal structures of propagating vortices are independent of parameter history, initial conditions, and system's length. They do, however, depend on the axial boundary conditions, the driving rate of the inner cylinder and the through-flow rate. Our analysis of the amplitude equation shows that the pattern selection can be described by a nonlinear eigenvalue problem with the frequency being the eigenvalue. Approaching the border between absolute and convective instability the eigenvalue problem becomes effectively linear and the selection mechanism approaches that one of linear front propagation. PACS:47.54.+r,47.20.Ky,47.32.-y,47.20.FtComment: 15 pages (LateX-file), 8 figures (Postscript

    Na incorporation in Mo and CuInSe from production processes

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    Abstract Results of characterization of thin "lms of Mo deposited by DC magnetron sputtering on soda-lime glass (Mo/SLG) and CuInSe (CIS) on Mo/SLG are presented. The primary objective of the work was to clarify the factors determining the concentration of Na in commercial-grade CIS. Mo "lms were deposited by three laboratories manufacturing CIS thin "lm solar cells. Analysis was by secondary ion mass spectrometry, scanning electron microscopy and X-ray di!raction. Changes in Mo deposition parameters in general a!ected the Na level but there was no obvious link to any single Mo deposition parameter. Oxygen content directly a!ected the Na level. The Na behavior was not obviously connected to "lm preferred orientation. Selenization of the Mo layers was also examined. Elemental Se vapor was found to produce signi"cantly less selenization than H Se. The amount of selenization was also strongly dependent upon Mo deposition conditions, although a speci"c source of the change in reaction rate was not found. Na distributions in the CIS deposited on the Mo were not limited by the di!usivity of the Na. The Na concentration in the CIS was increased by annealing the Mo "lms both with and without intentionally added Na. The Na level in the CIS appears to be set more by the CIS deposition process than by the Na concentration in the Mo so long as the Mo contains sucientNato0927−0248/99/cient Na to 0927-0248/99/ -see front matter 1999 Published by Elsevier Science B.V. All rights reserved. PII: S 0 9 2 7 -0 2 4 8 ( 9 9 ) 0 0 0 2 6 -4 saturate the available sites in the CIS. 1999 Published by Elsevier Science B.V. All rights reserved

    Perceptions and utilization of primary health care services in Iraq: findings from a national household survey

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    <p>Abstract</p> <p>Background</p> <p>After many years of sanctions and conflict, Iraq is rebuilding its health system, with a strong emphasis on the traditional hospital-based services. A network exists of public sector hospitals and clinics, as well as private clinics and a few private hospitals. Little data are available about the approximately 1400 Primary Health Care clinics (PHCCs) staffed with doctors. How do Iraqis utilize primary health care services? What are their preferences and perceptions of public primary health care clinics and private primary care services in general? How does household wealth affect choice of services?</p> <p>Methods</p> <p>A 1256 household national survey was conducted in the catchment areas of randomly selected PHCCs in Iraq. A cluster of 10 households, beginning with a randomly selected start household, were interviewed in the service areas of seven public sector PHCC facilities in each of 17 of Iraq's 18 governorates. A questionnaire was developed using key informants. Teams of interviewers, including both males and females, were recruited and provided a week of training which included field practice. Teams then gathered data from households in the service areas of randomly selected clinics.</p> <p>Results</p> <p>Iraqi participants are generally satisfied with the quality of primary care services available both in the public and private sector. Private clinics are generally the most popular source of primary care, however the PHCCs are utilized more by poorer households. In spite of free services available at PHCCs many households expressed difficulty in affording health care, especially in the purchase of medications. There is no evidence of informal payments to secure health services in the public sector.</p> <p>Conclusions</p> <p>There is widespread satisfaction reported with primary health care services, and levels did not differ appreciably between public and private sectors. The public sector PHCCs are preferentially used by poorer populations where they are important providers. PHCC services are indeed free, with little evidence of informal payments to providers.</p

    Regulation of CHK1 inhibitor resistance by a c-Rel and USP1 dependent pathway

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    AbstractWe previously discovered that deletion of c-Rel in the EÎŒ-Myc mouse model of lymphoma results in earlier onset of disease, a finding that contrasted with the expected function of this NF-ÎșB subunit in B-cell malignancies. Here we report that c-rel -/- E”-Myc cells have an unexpected and major defect in the CHK1 pathway, with almost undetectable levels of CHK1 and CLSPN protein leading to therapeutic resistance to the highly specific CHK1 inhibitor (CHK1i) CCT244747. Similar downregulation of CHK1 levels was also seen in CCT244747 resistant U20S osteosarcoma cells. Further investigation revealed that downregulation of the deubiquitinase USP1 is responsible, at least in part, for these effects. Importantly, we demonstrate that c-rel -/- E”-Myc lymphoma cells survive though upregulation of compensatory PI3K/AKT pathway activity. Moreover, targeting this pathway with Pictilisib (GDC-0941) effectively killed c-rel -/- E”-Myc in vivo, while having no effect on wild type EÎŒ-Myc cells. This data reveals an NF-ÎșB regulated pathway controlling CHK1 activity in cancer cells and identifies a potential mechanism for both acquiring and overcoming CHK1i resistance in cancer patients.</jats:p
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