420 research outputs found

    How Does Folding Modulate Thermal Conductivity of Graphene

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    We study thermal transport in folded graphene nanoribbons using molecular dynamics simulations and the non-equilibrium Green's function method. It is found that the thermal conductivity of flat graphene nanoribbons can be modulated by folding and changing interlayer couplings. The analysis of transmission reveals that the reduction of thermal conductivity is due to scattering of low frequency phonons by the folds. Our results suggest that folding can be utilized in the modulation of thermal transport properties in graphene and other two dimensional materials.Comment: published in Applied Physics Letters 201

    Surface modification of magnesium alloy AZ31 for improved biocompatibility

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    Master of Science (MSc) in Chemical Science

    Quantifying morphological heterogeneity: a study of more than 1 000 000 individual stored red blood cells

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    Background and Objectives The morphology of red blood cells (RBCs) deteriorates progressively during hypothermic storage. The degree of deterioration varies between individual cells, resulting in a highly heterogeneous population of cells contained within each RBC unit. Current techniques capable of categorizing the morphology of individual stored RBCs are manual, laborious, error-prone procedures that limit the number of cells that can be studied. Our objective was to create a simple, automated system for high-throughput RBC morphology classification. Materials and Methods A simple microfluidic device, designed to enable rapid, consistent acquisition of images of optimally oriented RBCs, was fabricated using soft lithography. A custom image analysis algorithm was developed to categorize the morphology of each individual RBC in the acquired images. The system was used to determine morphology of individual RBCs in several RBC units stored hypothermically for 6–8 weeks. Results The system was used to automatically determine the distribution of cell diameter within each morphological class for >1,000,000 individual stored RBCs (speed: >10,000 cells/hour; accuracy: 91.9% low-resolution, 75.3% high-resolution). Diameter mean and standard deviation by morphology class: discocyte 7.80±0.49?m, echinocyte 1 7.61±0.63?m, echinocyte 2 7.02±0.61?m, echinocyte 3 6.47±0.42?m, sphero-echinocyte 6.01±0.26?m, spherocyte 6.02±0.27?m, stomatocyte 1 6.95±0.61?m, stomatocyte 2 7.32 ± 0.47?m. Conclusion The automated morphology classification procedure described in this study is significantly simpler, faster and less subjective than conventional manual procedures. The ability to evaluate the morphology of individual RBCs automatically, rapidly and in statistically significant numbers enabled us to perform the most extensive study of stored RBC morphology to date

    Is hyperuricemia an independent risk factor for new-onset chronic kidney disease?: a systematic review and meta-analysis based on observational cohort studies

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    This article discusses the role of interrogation in intelligence during the Second World War, and it focuses on the importance of culture in the collection of Human Intelligence in the European theatre of operation. It argues that cultural issues, including but not limited to language knowledge, provided an added value to interrogation, interviewing and questioning during and after the Second World War, for example through the employment of native speakers, in particular former refugees and enemy aliens. The article also highlights some of the flaws involved in this process, which led to bad prisoner handling and therefore bad intelligence collection. It also tries to complement archival sources with personal accounts and oral histories in order to achieve a deeper understanding of the role of the human being in the collection of intelligence through interrogation and questioning

    NCACO-score: An effective main-chain dependent scoring function for structure modeling

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    <p>Abstract</p> <p>Background</p> <p>Development of effective scoring functions is a critical component to the success of protein structure modeling. Previously, many efforts have been dedicated to the development of scoring functions. Despite these efforts, development of an effective scoring function that can achieve both good accuracy and fast speed still presents a grand challenge.</p> <p>Results</p> <p>Based on a coarse-grained representation of a protein structure by using only four main-chain atoms: N, Cα, C and O, we develop a knowledge-based scoring function, called NCACO-score, that integrates different structural information to rapidly model protein structure from sequence. In testing on the Decoys'R'Us sets, we found that NCACO-score can effectively recognize native conformers from their decoys. Furthermore, we demonstrate that NCACO-score can effectively guide fragment assembly for protein structure prediction, which has achieved a good performance in building the structure models for hard targets from CASP8 in terms of both accuracy and speed.</p> <p>Conclusions</p> <p>Although NCACO-score is developed based on a coarse-grained model, it is able to discriminate native conformers from decoy conformers with high accuracy. NCACO is a very effective scoring function for structure modeling.</p

    A rapid paper-based test for quantifying sickle hemoglobin in blood samples from patients with sickle cell disease

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    Quantification of sickle hemoglobin (HbS) in patients with sickle cell disease (SCD) undergoing hydroxyurea or chronic transfusion therapy is essential to monitoring the effectiveness of these therapies. The clinical monitoring of %HbS using conventional laboratory methods is limited by high per-test costs and long turnaround times usually associated with these methods. Here we demonstrate a simple, rapid, inexpensive paper-based assay capable of quantifying %HbS in blood samples from patients with SCD. A 20 ?L droplet of whole blood and hemoglobin solubility buffer was deposited on chromatography paper. The relative color intensities of regions of the resulting blood stain, determined by automated image analysis, are used to estimate %HbS. We compared the paper-based assay with hemoglobin electrophoresis (comparison method) using blood samples from 88 subjects. The test shows high correlation (R2 = 0.86) and strong agreement (standard deviation of difference = 7 %HbS) with conventional Hb electrophoresis measurement of %HbS, and closely approximates clinically predicted change in %HbS with transfusion therapy (mean difference 2.6 %HbS, n = 4). The paper-based assay can be completed in less than 35 minutes and has a per-test cost less than $0.25. The assay is accurate across a wide range of HbS levels (10–97%) and hemoglobin concentrations (5.6–12.9 g/dL) and is unaffected by high levels of HbF (up to 80.6%). This study demonstrates the feasibility of the paper-based %HbS assay. The paper-based test could improve clinical care for SCD, particularly in resource-limited settings, by enabling more rapid and less expensive %HbS monitoring

    Chinese scientific drilling №1 well diamonds coring bit technology

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    Показана комплексная буровая технология с применением винтового двигателя, гидроударника и колонкового бурения алмазной импрегнированной коронкой, при бурении высоковольтных метаморфизованных пород скважины № 1 глубиной 5000 м в КНР. Разработаны оптимальные конструкции коронок и матрицы для предотвращения влияния ударной силы на алмазную коронку. Бурение в твердых породах с использованием разработаной технологии дало позитивные результаты
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