5,587 research outputs found

    The thermal evolution of nuclear matter at zero temperature and definite baryon number density in chiral perturbation theory

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    The thermal properties of cold dense nuclear matter are investigated with chiral perturbation theory. The evolution curves for the baryon number density, baryon number susceptibility, pressure and the equation of state are obtained. The chiral condensate is calculated and our result shows that when the baryon chemical potential goes beyond 1150MeV1150 \mathrm{MeV}, the absolute value of the quark condensate decreases rapidly, which indicates a tendency of chiral restoration.Comment: 17 pages, 9 figures, revtex

    Evaluation of a new high-throughput method for identifying quorum quenching bacteria

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    Quorum sensing (QS) is a population-dependent mechanism for bacteria to synchronize social behaviors such as secretion of virulence factors. The enzymatic interruption of QS, termed quorum quenching (QQ), has been suggested as a promising alternative anti-virulence approach. In order to efficiently identify QQ bacteria, we developed a simple, sensitive and high-throughput method based on the biosensor Agrobacterium tumefaciens A136. This method effectively eliminates false positives caused by inhibition of growth of biosensor A136 and alkaline hydrolysis of N-acylhomoserine lactones (AHLs), through normalization of beta-galactosidase activities and addition of PIPES buffer, respectively. Our novel approach was successfully applied in identifying QQ bacteria among 366 strains and 25 QQ strains belonging to 14 species were obtained. Further experiments revealed that the QQ strains differed widely in terms of the type ofQQenzyme, substrate specificity and heat resistance. The QQ bacteria identified could possibly be used to control disease in aquaculture

    The solutions of classical and nonlocal nonlinear Schr\"{o}dinger equations with nonzero backgrounds: Bilinearisation and reduction approach

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    In this paper we develop a bilinearisation-reduction approach to derive solutions to the classical and nonlocal nonlinear Schr\"{o}dinger (NLS) equations with nonzero backgrounds. We start from the second order Ablowitz-Kaup-Newell-Segur coupled equations as an unreduced system. With a pair of solutions (q0,r0)(q_0,r_0) we bilinearize the unreduced system and obtain solutions in terms of quasi double Wronskians. Then we implement reductions by introducing constraints on the column vectors of the Wronskians and finally obtain solutions to the reduced equations, including the classical NLS equation and the nonlocal NLS equations with reverse-space, reverse-time and reverse-space-time, respectively. With a set of plane wave solution (q0,r0)(q_0,r_0) as a background solution, we present explicit formulae for these column vectors. As examples, we analyze and illustrate solutions to the focusing NLS equation and the reverse-space nonlocal NLS equation. In particular, we present formulae for the rouge waves of arbitrary order for the focusing NLS equation.Comment: 44 pages, 11 figure

    A novel multifunctional biomedical material based on polyacrylonitrile:preparation and characterization

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    Wet spun microfibers have great potential in the design of multifunctional controlled release materials. Curcumin (Cur) and vitamin E acetate (Vit. E Ac) were used as a model drug system to evaluate the potential application of the drug-loaded microfiber system for enhanced delivery. The drugs and polyacrylonitrile (PAN) were blended together and spun to produce the target drug-loaded microfiber using an improved wet-spinning method and then the microfibers were successfully woven into fabrics. Morphological, mechanical properties, thermal behavior, drug release performance characteristics, and cytocompatibility were determined. The drug-loaded microfiber had a lobed “kidney” shape with a height of 50 ~ 100 ÎŒm and width of 100 ~ 200 ÎŒm. The addition of Cur and Vit. E Ac had a great influence on the surface and cross section structure of the microfiber, leading to a rough surface having microvoids. X-ray diffraction and Fourier transform infrared spectroscopy indicated that the drugs were successfully encapsulated and dispersed evenly in the microfilament fiber. After drug loading, the mechanical performance of the microfilament changed, with the breaking strength improved slightly, but the tensile elongation increased significantly. Thermogravimetric results showed that the drug load had no apparent adverse effect on the thermal properties of the microfibers. However, drug release from the fiber, as determined through in-vitro experiments, is relatively low and this property is maintained over time. Furthermore, in-vitro cytocompatibility testing showed that no cytotoxicty on the L929 cells was found up to 5% and 10% respectively of the theoretical drug loading content (TDLC) of curcumin and vitamin E acetate. This study provides reference data to aid the development of multifunctional textiles and to explore their use in the biomedical material field

    Nickel Nitride Particles Supported on 2D Activated Graphene–Black Phosphorus Heterostructure: An Efficient Electrocatalyst for the Oxygen Evolution Reaction

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    Hydrogen is regarded as the most promising green clean energy in the 21st century. Developing the highly efficient and low‐cost electrocatalysts for oxygen evolution reaction (OER) is of great concern for the hydrogen industry. In the water electrolyzed reaction, the overpotential and the kinetics are the main hurdles for OER. Therefore, an efficient and durable oxygen evolution reaction electrocatalyst is required. In this study, an activated graphene (AG)–black phosphorus (BP) nanosheets hybrid is fabricated for supporting Ni3N particles (Ni3N/BP‐AG) in the application of OER. The Ni3N particles are combined with the BP‐AG heterostructure via facile mechanical ball milling under argon protection. The synthesized Ni3N/BP‐AG shows excellent catalytic performance toward the OER, demanding the overpotential of 233 mV for a current density of 10 mA cm−2 with a Tafel slope of 42 mV dec−1. The Ni3N/BP‐AG catalysts also show remarkable stability with a retention rate of the current density of about 86.4% after measuring for 10 000 s in potentiostatic mode.A black phosphorus (BP)–activated graphene (AG) heterostructure is designed for supporting nickel nitride (Ni3N) to enhance the performance of oxygen evolution reaction (OER). The Ni3N/BP‐AG exhibits excellent electrocatalytic performance toward OER with low overpotential and small Tafel slope. It also shows remarkable stability with a retention rate of ≈86.4% OER activity after 10 000 s.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152804/1/smll201901530.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152804/2/smll201901530_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152804/3/smll201901530-sup-0001-S1.pd
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