5,587 research outputs found
The thermal evolution of nuclear matter at zero temperature and definite baryon number density in chiral perturbation theory
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 , 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
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
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 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
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
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 âkidneyâ 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 GrapheneâBlack Phosphorus Heterostructure: An Efficient Electrocatalyst for the Oxygen Evolution Reaction
Hydrogen is regarded as the most promising green clean energy in the 21st century. Developing the highly efficient and lowâcost 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)âblack phosphorus (BP) nanosheets hybrid is fabricated for supporting Ni3N particles (Ni3N/BPâAG) in the application of OER. The Ni3N particles are combined with the BPâAG heterostructure via facile mechanical ball milling under argon protection. The synthesized Ni3N/BPâAG shows excellent catalytic performance toward the OER, demanding the overpotential of 233 mV for a current density of 10 mA cmâ2 with a Tafel slope of 42 mV decâ1. The Ni3N/BPâAG 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)âactivated graphene (AG) heterostructure is designed for supporting nickel nitride (Ni3N) to enhance the performance of oxygen evolution reaction (OER). The Ni3N/BPâAG exhibits excellent electrocatalytic performance toward OER with low overpotential and small Tafel slope. It also shows remarkable stability with a retention rate of â86.4% 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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