30,244 research outputs found

    Strong One-Dimensional Characteristics of Hole-Carriers in ReS2 and ReSe2.

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    Each plane of layered ReS2 and ReSe2 materials has 1D chain structure, from which intriguing properties such as 1D character of the exciton states and linearly polarized photoluminescence originate. However, systematic studies on the 1D character of charge carriers have not been done yet. Here, we report on systematic and comparative studies on the energy-momentum dispersion relationships of layered transition metal dichalcogenides ReS2 and ReSe2 by angle resolved photoemission. We found that the valence band maximum or the minimum energy for holes is located at the high symmetric Z-point for both materials. However, the out-of-plane ([Formula: see text]) dispersion for ReSe2 (20 meV) is found to be much smaller than that of ReS2 (150 meV). We observe that the effective mass of the hole carriers along the direction perpendicular to the chain is about 4 times larger than that along the chain direction for both ReS2 and ReSe2. Remarkably, the experimentally measured hole effective mass is about twice heavier than that from first principles calculation for ReS2 although the in-plane anisotropy values from the experiment and calculations are comparable. These observation indicate that bulk ReS2 and ReSe2 are unique semiconducting transition metal dichalcogenides having strong one-dimensional characters

    Deficiency of Capicua disrupts bile acid homeostasis

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    Capicua (CIC) has been implicated in pathogenesis of spinocerebellar ataxia type 1 and cancer in mammals; however, the in vivo physiological functions of CIC remain largely unknown. Here we show that Cic hypomorphic (Cic-L-/-) mice have impaired bile acid (BA) homeostasis associated with induction of proinflammatory cytokines. We discovered that several drug metabolism and BA transporter genes were down-regulated in Cic-L-/- liver, and that BA was increased in the liver and serum whereas bile was decreased within the gallbladder of Cic-L-/- mice. We also found that levels of proinflammatory cytokine genes were up-regulated in Cic-L-/- liver. Consistent with this finding, levels of hepatic transcriptional regulators, such as hepatic nuclear factor 1 alpha (HNF1 alpha), CCAAT/enhancer-binding protein beta (C/EBP beta), forkhead box protein A2 (FOXA2), and retinoid X receptor alpha (RXR alpha), were markedly decreased in Cic-L-/- mice. Moreover, induction of tumor necrosis factor alpha (Tnf alpha) expression and decrease in the levels of FOXA2, C/EBP beta, and RXRa were found in Cic-L-/- liver before BA was accumulated, suggesting that inflammation might be the cause for the cholestasis in Cic-L-/- mice. Our findings indicate that CIC is a critical regulator of BA homeostasis, and that its dysfunction might be associated with chronic liver disease and metabolic disorders.open11810Ysciescopu

    High Fidelity Tape Transfer Printing Based On Chemically Induced Adhesive Strength Modulation

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    Transfer printing, a two-step process (i.e. picking up and printing) for heterogeneous integration, has been widely exploited for the fabrication of functional electronics system. To ensure a reliable process, strong adhesion for picking up and weak or no adhesion for printing are required. However, it is challenging to meet the requirements of switchable stamp adhesion. Here we introduce a simple, high fidelity process, namely tape transfer printing(TTP), enabled by chemically induced dramatic modulation in tape adhesive strength. We describe the working mechanism of the adhesion modulation that governs this process and demonstrate the method by high fidelity tape transfer printing several types of materials and devices, including Si pellets arrays, photodetector arrays, and electromyography (EMG) sensors, from their preparation substrates to various alien substrates. High fidelity tape transfer printing of components onto curvilinear surfaces is also illustrated

    Superconductivity below 20 K in heavily electron-doped surface layer of FeSe bulk crystal

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    A superconducting transition temperature (T-c) as high as 100 K was recently discovered in one monolayer FeSe grown on SrTiO3. The discovery ignited efforts to identify the mechanism for the markedly enhanced T-c from its bulk value of 8 K. There are two main views about the origin of the T-c enhancement: interfacial effects and/or excess electrons with strong electron correlation. Here, we report the observation of superconductivity below 20 K in surface electron-doped bulk FeSe. The doped surface layer possesses all the key spectroscopic aspects of the monolayer FeSe on SrTiO3. Without interfacial effects, the surface layer state has a moderate T-c of 20 K with a smaller gap opening of 4.2 meV. Our results show that excess electrons with strong correlation cannot induce the maximum T-c, which in turn reveals the need for interfacial effects to achieve the highest T-c in one monolayer FeSe on SrTiO3.1116Ysciescopu

    On the combination of high-pressure and low-pressure exhaust gas recirculation loops for improved fuel economy and reduced emissions in high-speed direct-injection engines

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    In this paper, an experimental study of the combination of low-pressure and high-pressure exhaust gas recirculation architectures has been carried out. In the first part of the paper, the effects of both high-pressure and low-pressure exhaust gas recirculation architectures on engine behaviour and performance are analysed by means of a series of steady tests. In the second part, the effects of the combination of both architectures are addressed. The results show that the low-pressure configuration improves high-pressure exhaust gas recirculation results in brake-specific fuel consumption, nitrogen oxides and exhaust gas opacity; nevertheless, hydrocarbon emissions are increased, especially during the engine warm up. In addition, the exhaust gas recirculation rate achieved with low-pressure systems is limited by the pressure difference between diesel particulate matter outlet and compressor inlet; therefore, the high-pressure system can be used to achieve the required exhaust gas recirculation levels without increasing pumping losses. In this sense, the combination of both exhaust gas recirculation layouts offers significant advantages to reduce emissions and fuel consumption to meet future emission requirements.This work was supported by the Ministry of Science and Innovation (Spanish Government) [grant number IPT-370000-2010-022].Desantes Fernández, JM.; Luján, JM.; Plá Moreno, B.; Soler Muniesa, JA. (2013). On the combination of high-pressure and low-pressure exhaust gas recirculation loops for improved fuel economy and reduced emissions in high-speed direct-injection engines. International Journal of Engine Research. 14(1):3-11. https://doi.org/10.1177/1468087412437623S311141Taylor, A. M. K. P. (2008). Science review of internal combustion engines. Energy Policy, 36(12), 4657-4667. doi:10.1016/j.enpol.2008.09.001Lü, X.-C., Chen, W., & Huang, Z. (2005). A fundamental study on the control of the HCCI combustion and emissions by fuel design concept combined with controllable EGR. Part 2. Effect of operating conditions and EGR on HCCI combustion. Fuel, 84(9), 1084-1092. doi:10.1016/j.fuel.2004.12.015Nakano, M., Mandokoro, Y., Kubo, S., & Yamazaki, S. (2000). Effects of exhaust gas recirculation in homogeneous charge compression ignition engines. International Journal of Engine Research, 1(3), 269-279. doi:10.1243/1468087001545173Zheng, M., Reader, G. T., & Hawley, J. G. (2004). Diesel engine exhaust gas recirculation––a review on advanced and novel concepts. Energy Conversion and Management, 45(6), 883-900. doi:10.1016/s0196-8904(03)00194-8Hountalas, D. T., Mavropoulos, G. C., & Binder, K. B. (2008). Effect of exhaust gas recirculation (EGR) temperature for various EGR rates on heavy duty DI diesel engine performance and emissions. Energy, 33(2), 272-283. doi:10.1016/j.energy.2007.07.002Luján, J. M., Galindo, J., Serrano, J. R., & Pla, B. (2008). A methodology to identify the intake charge cylinder-to-cylinder distribution in turbocharged direct injection Diesel engines. Measurement Science and Technology, 19(6), 065401. doi:10.1088/0957-0233/19/6/065401Ladommatos, N., Abdelhalim, S., & Zhao, H. (2000). The effects of exhaust gas recirculation on diesel combustion and emissions. International Journal of Engine Research, 1(1), 107-126. doi:10.1243/1468087001545290Maiboom, A., Tauzia, X., & Hétet, J.-F. (2008). Influence of high rates of supplemental cooled EGR on NOxand PM emissions of an automotive HSDI diesel engine using an LP EGR loop. International Journal of Energy Research, 32(15), 1383-1398. doi:10.1002/er.1455Gautier, P., Albrecht, A., Chasse, A., Moulin, P., Pagot, A., Fontvieille, L., & Issartel, D. (2009). A Simulation Study of the Impact of LP EGR on a Two-Stage Turbocharged Diesel Engine. Oil & Gas Science and Technology - Revue de l’IFP, 64(3), 361-379. doi:10.2516/ogst/2009019Torregrosa, A. J., Olmeda, P., Martín, J., & Degraeuwe, B. (2006). Experiments on the influence of inlet charge and coolant temperature on performance and emissions of a DI Diesel engine. Experimental Thermal and Fluid Science, 30(7), 633-641. doi:10.1016/j.expthermflusci.2006.01.00

    FIH-1, a novel interactor of mindbomb, functions as an essential anti-angiogenic factor during zebrafish vascular development

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    Objective: It has been shown that Mindbomb (Mib), an E3 Ubiquitin ligase, is an essential modulator of Notch signaling during development. However, its effects on vascular development remain largely unknown

    Who Watches the Watchmen? An Appraisal of Benchmarks for Multiple Sequence Alignment

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    Multiple sequence alignment (MSA) is a fundamental and ubiquitous technique in bioinformatics used to infer related residues among biological sequences. Thus alignment accuracy is crucial to a vast range of analyses, often in ways difficult to assess in those analyses. To compare the performance of different aligners and help detect systematic errors in alignments, a number of benchmarking strategies have been pursued. Here we present an overview of the main strategies--based on simulation, consistency, protein structure, and phylogeny--and discuss their different advantages and associated risks. We outline a set of desirable characteristics for effective benchmarking, and evaluate each strategy in light of them. We conclude that there is currently no universally applicable means of benchmarking MSA, and that developers and users of alignment tools should base their choice of benchmark depending on the context of application--with a keen awareness of the assumptions underlying each benchmarking strategy.Comment: Revie
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