356 research outputs found
Five-dimensional AGT Relation and the Deformed beta-ensemble
We discuss an analog of the AGT relation in five dimensions. We define a
q-deformation of the beta-ensemble which satisfies q-W constraint. We also show
a relation with the Nekrasov partition function of 5D SU(N) gauge theory with
N_f=2N.Comment: 38page. References and an appendix for 4D case added. Typos correcte
QFT approach to dressed particle processes in preheating and non-perturbative mechanism in kinematically-forbidden regime
We provide a quantum-field theoretic formulation of dressed particle dynamics
that systematically include particle production and scattering/decay processes
in the preheating era. Our approach is based on the so-called perturbation
theory in the Furry picture, in which coherent background fields (i.e.,
inflaton and the expanding Universe) are treated non-perturbatively whereas
interactions between dressed particles are taken into account perturbatively.
As application, we consider the instant preheating mechanism and compute the
number of produced particles explicitly, assuming that the coherent fields are
adiabatic. We find a novel non-perturbative particle-production mechanism,
which is kinematically forbidden within the conventional perturbative
calculation and produces particles exponentially efficiently than the
perturbative one does.Comment: 30 pages, 5 figures, v2:comments added, typos fixe
Water-Soluble Extract of Pacific Krill Prevents Triglyceride Accumulation in Adipocytes by Suppressing PPARγ and C/EBPα Expression
BACKGROUND: Pacific Krill (Euphausia pacifica) are small, red crustaceans, similar to shrimp, that flourish in the North Pacific and are eaten in Japan. METHODS AND FINDINGS: We investigated the effect of a water-soluble extract of Pacific Krill on adipocytes and discovered that this extract suppressed triglyceride accumulation in adipocytes. Furthermore, the water-soluble extract of Pacific Krill suppressed the expression of two master regulators of adipocyte differentiation, peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT enhancer binding protein alpha (C/EBPα). C/EBPβ promotes PPARγ and C/EBPα expression, but the water-soluble extract of Pacific Krill did not inhibit the expression of C/EBPβ or C/EBPβ-mediated transcriptional activation. The Pacific Krill extract was more effective than a PPARγ antagonist in suppressing PPARγ and C/EBPα expression. CONCLUSIONS: These results indicated that the water-soluble extract of Pacific Krill was not simply a PPARγ antagonist, but that it prevented triglyceride accumulation in adipocytes by suppression of PPARγ and C/EBPα via a pathway that is independent of C/EBPβ
Isolation of Acein-2, a novel angiotensin-I-converting enzyme inhibitory peptide derived from a tryptic hydrolysate of human plasma
AbstractWe previously described a novel angiotensin-I-converting enzyme (ACE) inhibitory peptide, designated Acein-1, that was isolated from a tryptic hydrolysate of human plasma. We now report a second such inhibitory peptide, Acein-2 obtained from the same hydrolysate. The peptide was purified by gel filtration and cation exchange chromatography followed by reversed-phase gradient and isocratic high performance liquid chromatography. Acein-2 was found to be a tripeptide, Leu-Ile-Tyr, which is thought to correspond to f(518–520) of human α2-macroglobulin. The synthetic tripeptide showed a potent dose-dependent inhibition of ACE, with an IC50 value of 0.82 μmol/l. Lineweaver–Burk plots suggested that Acein-2 as well as the previously described Acein-1 are non-competitive inhibitors
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