474 research outputs found

    Grazing incidence x ray fluorescence analysis for non destructive determination of In and Ga depth profiles in Cu In,Ga Se2 absorber films

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    Development of highly efficient thin film solar cells involves band gap engineering by tuning their elemental composition with depth. Here we show that grazing incidence X ray fluorescence GIXRF analysis using monochromatic synchrotron radiation and well characterized instrumentation is suitable for a non destructive and reference free analysis of compositional depth profiles in thin films. Variation of the incidence angle provides quantitative access to the in depth distribution of the elements, which are retrieved from measured fluorescence intensities by modeling parameterized gradients and fitting calculated to measured fluorescence intensities. Our results show that double Ga gradients in Cu In1 x,Gax Se2 can be resolved by GIXR

    Deep learning-based post-processing of real-time MRI to assess and quantify dynamic wrist movement in health and disease

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    While morphologic magnetic resonance imaging (MRI) is the imaging modality of choice for the evaluation of ligamentous wrist injuries, it is merely static and incapable of diagnosing dynamic wrist instability. Based on real-time MRI and algorithm-based image post-processing in terms of convolutional neural networks (CNNs), this study aims to develop and validate an automatic technique to quantify wrist movement. A total of 56 bilateral wrists (28 healthy volunteers) were imaged during continuous and alternating maximum ulnar and radial abduction. Following CNN-based automatic segmentations of carpal bone contours, scapholunate and lunotriquetral gap widths were quantified based on dedicated algorithms and as a function of wrist position. Automatic segmentations were in excellent agreement with manual reference segmentations performed by two radiologists as indicated by Dice similarity coefficients of 0.96 ± 0.02 and consistent and unskewed Bland–Altman plots. Clinical applicability of the framework was assessed in a patient with diagnosed scapholunate ligament injury. Considerable increases in scapholunate gap widths across the range-of-motion were found. In conclusion, the combination of real-time wrist MRI and the present framework provides a powerful diagnostic tool for dynamic assessment of wrist function and, if confirmed in clinical trials, dynamic carpal instability that may elude static assessment using clinical-standard imaging modalities

    NMR and Metabolomics—A Roadmap for the Future

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    Metabolomics investigates global metabolic alterations associated with chemical, biological, physiological, or pathological processes. These metabolic changes are measured with various analytical platforms including liquid chromatography-mass spectrometry (LC-MS), gas chromatographymass spectrometry (GC-MS) and nuclear magnetic resonance spectroscopy (NMR). While LC-MS methods are becoming increasingly popular in the field of metabolomics (accounting for more than 70% of published metabolomics studies to date), there are considerable benefits and advantages to NMR-based methods for metabolomic studies. In fact, according to PubMed, more than 926 papers on NMR-based metabolomics were published in 2021—the most ever published in a given year. This suggests that NMR-based metabolomics continues to grow and has plenty to offer to the scientific community. This perspective outlines the growing applications of NMR in metabolomics, highlights several recent advances in NMR technologies for metabolomics, and provides a roadmap for future advancements

    Emerging media and press freedoms as determinants of nonviolent and violent political conflicts, 1990–2006

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    © 2016, © The Author(s) 2016. Using aggregate-level data, this study compares instances of intrastate political conflict that occurred in both nonviolent and violent forms. Specifically, analyses presented in this study examine the relationships that exist between diffusion rates of emerging media and enhanced press freedoms in countries that experienced differing types of conflicts from 1990 through 2006. Through a series of analytic models, the results observed here indicate that higher levels of emerging media and press freedoms are better predictors of nonviolent—as opposed to violent—conflict. Findings from this study thus bridge an important gap in the literature between communication and political science research in establishing linkages between emerging media technologies and press freedoms and their interconnections with nonviolent and violent political conflict. Implications for related interdisciplinary fields are discussed

    Formation of a ZnS Zn S,O bilayer buffer on CuInS2 thin film solar cell absorbers by chemical bath deposition

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    The application of Zn compounds as buffer layers was recently extended to wide gap CuInS2 CIS based thin film solar cells. Using a new chemical deposition route for the buffer preparation aiming at the deposition of a single layer, nominal ZnS buffer without the need for any toxic reactants such as, e.g. hydrazine, has helped to achieve a similar efficiency as respective CdS buffered reference devices. In order to shed light on the differences of other Zn compound buffers deposited in conventional chemical baths CBD compared to the buffer layers deposited by this alternative CBD process, the composition of the deposited buffers was investigated by x ray excited Auger electron and x ray photoelectron spectroscopy to potentially clarify their superiority in terms of device performance. We have found that in the early stages of this alternative CBD process a thin ZnS layer is formed on the CIS, whereas in the second half of the CBD the growth rate is greatly increased and Zn S,O with a ZnS ZnS ZnO ratio of approx. 80 is deposited. Thus, a ZnS Zn S,O bi layer buffer is deposited on the CIS thin film solar cell absorbers by the alternative chemical deposition route used in this investigation. No major changes of these findings after a postannealing of the buffer CIS sample series and re characterization could be identified

    Innovation highway Breakthrough milestones amp; key developments in chalcopyrite photovoltaics from a retrospective viewpoint

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    The present contribution is a summary of an event that was organized as a special evening session in Symposium V Chalcogenide Thin Film Solar Cells at the E MRS 2016 Spring Meeting, Lille, France. The presentations in this session were given by the coauthors of this paper. These authors present retrospectives of key developments in the amp; 64257;eld of Cu In,Ga S,Se 2 solar cells as they themselves had witnessed in their laboratories or companies. Also, anecdotes are brought up, which captured interesting circumstances in that evolutionary phase of the amp; 64257;eld. Be cause the focus was on historical perspectives rather than a comprehensive review of the amp; 64257;eld, recent develop ments intentionally were not addresse

    Connectivity mapping (ssCMap) to predict A20-inducing drugs and their antiinflammatory action in cystic fibrosis

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    Cystic fibrosis (CF) lung disease is characterized by chronic and exaggerated inflammation in the airways. Despite recent developments to therapeutically overcome the underlying functional defect in the cystic fibrosis transmembrane conductance regulator, there is still an unmet need to also normalize the inflammatory response. The prolonged and heightened inflammatory response in CF is, in part, mediated by a lack of intrinsic down-regulation of the proinflammatory NF-ÎșB pathway. We have previously identified reduced expression of the NF-ÎșB down-regulator A20 in CF as a key target to normalize the inflammatory response. Here, we have used publicly available gene array expression data together with a statistically significant connections’ map (sscMap) to successfully predict drugs already licensed for the use in humans to induce A20 mRNA and protein expression and thereby reduce inflammation. The effect of the predicted drugs on A20 and NF-ÎșB(p65) expression (mRNA) as well as proinflammatory cytokine release (IL-8) in the presence and absence of bacterial LPS was shown in bronchial epithelial cells lines (16HBE14o−, CFBE41o−) and in primary nasal epithelial cells from patients with CF (Phe508del homozygous) and non-CF controls. Additionally, the specificity of the drug action on A20 was confirmed using cell lines with tnfαip3 (A20) knockdown (siRNA). We also show that the A20-inducing effect of ikarugamycin and quercetin is lower in CF-derived airway epithelial cells than in non-CF cells

    Intermixing at the heterointerface between ZnS Zn S,O bilayer buffer and CuInS2 thin film solar cell absorber

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    The application of Zn compounds as buffer layers was recently extended to wide gap CuInS2 CIS based thin film solar cells. Using a new chemical deposition route for the buffer preparation aiming at the deposition of a single layer, nominal ZnS buffer without the need for any toxic reactants such as, e.g. hydrazine has helped to achieve a similar efficiency as respective CdS buffered reference devices. After identifying the deposited Zn compound, as ZnS Zn S,O bi layer buffer in former investigations [M. BĂ€r, A. Ennaoui, J. Klaer, T. Kropp, R. S ez Araoz, N. Allsop, I. Lauermann, H. W. Schock, and M.C. Lux Steiner, Formation of a ZnS Zn S,O bilayer buffer on CuInS2 thin film solar cell absorbers by chemical bath deposition , J. Appl. Phys., accepted.], this time the focus lies on potential diffusion intermixing processes at the buffer absorber interface possibly, clarifying the effect of the heat treatment, which drastically enhances the device performance of respective final solar cells. The interface formation was investigated by x ray photoelectron and x ray excited Auger electron spectroscopy. In addition, photoelectron spectroscopy PES measurements were also conducted using tuneable monochromatized synchrotron radiation in order to gain depth resolved information. The buffer side of the buffer absorber heterointerface were investigated by means of the characterization of Zn S,O ZnS CIS structures where the ZnS Zn S,O bi layer buffer was deposited successively by different deposition times. In order to make the in terms of PES information depth deeply buried absorber side of the buffer absorber heterointerface accessible for characterization, in these cases the buffer layer was etched away by dilute HClaq. We found that while out leached Cu from the absorber layer forms together with the educts in the chemical bath a Zn 1 Z ,Cu2Z S like interlayer between buffer and absorber, Zn is incorporated in the uppermost region of the absorber. Both effects are strongly enhanced by postannealing the Zn S,O ZnS CIS samples. However, it was determined that the major fraction of the Cu and Zn can be found quite close to the heterointerface in the buffer and absorber layer, respectively. Due to this limited in the range of one monolayer spatial extent, these diffusion mechanisms were rather interpreted as a CBD induced and heat treatment promoted Cu Zn ion exchange at the buffer absorber interface. Possible impacts of this intermixing on the performance of the final solar cell devices will also be discusse
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