616 research outputs found
Real-time hard-thermal-loop gluon self-energy in a semiquark-gluon plasma
In the real time formalism of the finite-temperature field theory, we compute
the one-loop gluon self-energy in a semi-quark-gluon plasma (QGP) where a
background filed has been introduced for the vector potential,
leading to a non-trivial expectation value for the Polyakov loop in the
deconfined phase. Explicit results of the gluon self-energies up to the
next-to-leading order in the hard-thermal-loop approximation are obtained. We
find that for the retarded/advanced gluon self-energy, the corresponding
contributions at next-to-leading order are formally analogous to the well-known
result at where the background field modification on the Debye
mass is entirely encoded in the second Bernoulli polynomials. The same feature
is shared by the leading order contributions in the symmetric gluon self-energy
where the background field modification becomes more complicated, including
both trigonometric functions and the Bernoulli polynomials. These contributions
are non-vanishing and reproduce the correct limit as .
In addition, the leading order contributions to the retarded/advanced gluon
self-energy and the next-to-leading order contributions to the symmetric gluon
self-energy are completely new as they only survive at . Given
the above results, we explicitly verify that the Kubo-Martin-Schwinger
condition can be satisfied in a semi-QGP with non-zero background field.Comment: final version published in PR
Polystyrene-b-poly(oligo(ethylene oxide) monomethyl ether methacrylate)-bpolystyrene triblock copolymers as potential carriers for hydrophobic drugs
A simple and effective method is introduced to synthesize a series of polystyrene-b-poly(oligo(ethylene oxide) monomethyl ether methacrylate)-b- polystyrene (PSt-b-POEOMA-b-PSt) triblock copolymers. The structures of PSt-b-POEOMA-b-PSt copolymers were characterized by Fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (1H NMR) spectroscopy. The molecular weight and molecular weight distribution of the copolymer were measured by gel permeation chromatography (GPC). Furthermore£ the self-assembling and drug-loaded behaviours of three different ratios of PSt-b-POEOMA-b-PSt were studied. These copolymers could readily self-assemble into micelles in aqueous solution. The vitamin E-loaded copolymer micelles were produced by the dialysis method. The micelle size and core-shell structure of the block copolymer micelles and the drug-loaded micelles were confirmed by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The thermal properties of the copolymer micelles before and after drug-loaded were investigated by different scanning calorimetry (DSC). The results show that the micelle size is slightly increased with increasing the content of hydrophobic segments and the micelles are still core-shell spherical structures after drug-loaded. Moreover, the glass transition temperature (Tg) of polystyrene is reduced after the drug loaded. The drug loading content (DLC) of the copolymer micelles is 70%-80% by ultraviolet (UV) photolithography analysis. These properties indicate the micelles self-assembled from PSt-b- POEOMA-b- PSt copolymers would have potential as carriers for the encapsulation of hydrophobic drugs
Host Genotype and Precipitation Influence of Fungal Endophyte Symbiosis and Mycotoxin Abundance in a Locoweed
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