TiO2纳米纺锤体负载Pt在氧还原反应中的应用

燃料电池中催化剂的稳定性是影响其实际应用的关键问题之一。本研究合成了锐钛矿型纺锤状TiO₂纳米材料,并负载纳米Pt制备了TiO₂-Pt双组分复合催化材料。将其制作成电极材料后,进行了TEM、XRD、拉曼光谱、电化学特性分析。结果表明：TiO₂-Pt材料中Pt纳米颗粒的TEM形貌与TiO₂的表面亲和力有关;该双组分催化剂呈现出两个单独的氧还原反应（ORR）峰;在负载Pt后,材料电荷传输电阻明显减小,使得TiO₂-Pt中TiO₂纺锤体组分上的ORR性能明显增强;紫外光可同时促进TiO₂-Pt中两组分的ORR性能;TiO₂-Pt比炭黑负载Pt具有更好的稳定性。     

Oral bioavailability enhancement of raloxifene by developing microemulsion using D-optimal mixture design: optimization and in-vivo pharmacokinetic study

The objective of this work was to utilize a potential of microemulsion for the improvement in oral bioavailability of raloxifene hydrochloride, a BCS class-II drug with 2% bioavailability. Drug-loaded microemulsion was prepared by water titration method using Capmul MCM C8, Tween 20, and Polyethylene glycol 400 as oil, surfactant, and co-surfactant respectively. The pseudo-ternary phase diagram was constructed between oil and surfactants mixture to obtain appropriate components and their concentration ranges that result in large existence area of microemulsion. D-optimal mixture design was utilized as a statistical tool for optimization of microemulsion considering oil, S_mix, and water as independent variables with percentage transmittance and globule size as dependent variables. The optimized formulation showed 100?±?0.1% transmittance and 17.85?±?2.78?nm globule size which was identically equal with the predicted values of dependent variables given by the design expert software. The optimized microemulsion showed pronounced enhancement in release rate compared to plain drug suspension following diffusion controlled release mechanism by the Higuchi model. The formulation showed zeta potential of value ?5.88?±?1.14?mV that imparts good stability to drug loaded microemulsion dispersion. Surface morphology study with transmission electron microscope showed discrete spherical nano sized globules with smooth surface. In-vivo pharmacokinetic study of optimized microemulsion formulation in Wistar rats showed 4.29-fold enhancements in bioavailability. Stability study showed adequate results for various parameters checked up to six months. These results reveal the potential of microemulsion for significant improvement in oral bioavailability of poorly soluble raloxifene hydrochloride.     

Risk for HIV infection among bisexual men seeking HIV-prevention services and risks posed to their female partners.

The present study interviewed gay (n?=?473) and bisexual men (n?=?146) as part of an HIV prevention program and investigated social cognitive factors associated with HIV risk. Results indicated that HIV risk in homosexual men was associated with sexual openness and connections to gay communities, factors not associated with risk for bisexual men. Compared with men at lower risk, those who practiced high-risk sex scored lower on measures of perceived safer sex norms, safer sex self-efficacy, and social skills. Bisexual men with primary female partners often had not disclosed their bisexuality to female partners (75%), and 64% had not modified their behavior to protect female partners. Bisexual men who engage in high-risk behaviors therefore pose a risk to female partners who may be unaware of their involvement with men. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Synthesis and stability analysis of papain-functionalized gold nanoparticles (P-AuNPs) for the colorimetric detection of mercury in milk

To detect mercury in dairy cow milk by colorimetric techniques, papain-functionalized gold nanoparticles (P-AuNPs) were synthesised. Papain-functionalized gold nanoparticles aggregated when mercury ions were introduced, causing their absorption peak to shift from 525 to 575 nm. Dynamic light scattering and transmission electron microscopy determined that aggregated P-AuNPs average sizes were 26.60 nm and 15.17–18.23 nm, respectively, with monodispersed. The detection limit of P-AuNPs for mercury in milk samples was 1.0 ppm with high recovery. This sensor showed relatively high selectivity and sensitivity towards Hg²⁺ ions in milk. This method shows utility in developing countries for monitoring the concentration of Hg²⁺ in water, milk and food items for safety purposes.     

LDES: detector design for version number attack detection using linear temporal logic based on discrete event system

International Journal of Information Security - The Internet Engineering Task Force (IETF) has defined routing protocols for low power and lossy networks (RPL) for constrained devices. RPL...     

Membranes in Solar-Driven Evaporation: Design Principles and Applications

Solar-driven evaporation process brings exciting opportunities to recover clean water and resources in a sustainable way from diverse sources like seawater and wastewater. Separation membranes, as a vital material in many environmental and energy applications, can contribute significantly to this process owing to their structural features. However, the unique roles of membranes in solar evaporator construction and process design are seldom recognized and not summarized yet from scientific principles and application demands, which forms the motivation of this review. Herein, the roles of membranes in different processes based on solar-driven evaporation are focused and the design principles of membrane materials and devices to meet the requirements of these applications are discussed. Fabrication strategies for photothermal membranes are introduced primarily, followed by a discussion on how to design membrane materials, devices, and processes to pursue optimal performance and realize advanced functions accompanied by evaporation. Furthermore, the future of this field is forecast with both challenges and opportunities.     

Programming pipelined CAD applications on message-passing architectures

Programming applications in computer-aided design of VLSI are difficult on parallel architectures, especially pipelined implementations derived from their sequential counterparts by algorithmic partitioning. The difficulty is primarily due to lack of good program development environments and tools. Our solution, applicable to message-passing architectures, is based upon a definition of a broad class of non-linear pipeline configurations and an asynchronous data-driven model for pipeline stage interactions. It provides object-oriented definitions of stages and interconnecting channels. These objects are embedded in C++ so that the correctness of application programs can be tested on a workstation in a simulated environment. The simulation is instrumented to provide data useful in assessing relative computational loading and balancing of stages. Thus a large part of program development can take place in the environment of a workstation familiar to the programmer. A non-trivial application is developed to illustrate these ideas.     

Protein Backbone Alteration in Non-Hairpin β-Turns: Impacts on Tertiary Folded Structure and Folded Stability

The importance of β-turns to protein folding has motivated extensive efforts to stabilize the motif with non-canonical backbone connectivity. Prior work has focused almost exclusively on turns between strands in a β-sheet (i. e., hairpins). Turns in other structural contexts are also common in nature and have distinct conformational preferences; however, design principles for their mimicry remain poorly understood. Here, we report strategies that stabilize non-hairpin β-turns through systematic evaluation of the impacts of backbone alteration on the high-resolution folded structure and folded stability of a helix-loop-helix prototype protein. Several well-established hairpin turn mimetics are shown detrimental to folded stability and/or hydrophobic core packing, while less-explored modification schemes that reinforce alternate turn types lead to improved stability and more faithful structural mimicry. Collectively, these results have implications in control over protein folding through chemical modification as well as the design of protein mimetics.