731 research outputs found
Proton dominance in the 2^+_2 -> 0^+_1 transition of N = Z\pm 2 nuclei around Si-28
E2 transitions in Si-30 are investigated in relation with intrinsic
deformations based on a method of antisymmetrized molecular dynamics. By
comparing E2 transition strengths in the mirror nuclei Si-30 and S-30,
transition matrix amplitudes M_p and M_n for protons and neutrons are discussed
in mirror analysis. Particular attention is paid to the M_n/M_p ratio in the
transition from the 2^+_2 state to the 0^+_1 state. The M_n/M_p ratio in Mg-26
and Si-26 is also investigated. It is found that the proton dominance in the
transition 2^+_2 -> 0^+_1 in Si-30 and Si-26 originates in the oblate trend of
the Z=14 proton structure.Comment: 7 pages, 7 figure
Giant Magnetoresistance in Nanogranular Magnets
We study the giant magnetoresistance of nanogranular magnets in the presence
of an external magnetic field and finite temperature. We show that the
magnetization of arrays of nanogranular magnets has hysteretic behaviour at low
temperatures leading to a double peak in the magnetoresistance which coalesces
at high temperatures into a single peak. We numerically calculate the
magnetization of magnetic domains and the motion of domain walls in this system
using a combined mean-field approach and a model for an elastic membrane moving
in a random medium, respectively. From the obtained results, we calculate the
electric resistivity as a function of magnetic field and temperature. Our
findings show excellent agreement with various experimental data.Comment: 4 pages, 3 figure
Thermoelectric performance of weakly coupled granular materials
We study thermoelectric properties of inhomogeneous nanogranular materials
for weak tunneling conductance between the grains, g_t < 1. We calculate the
thermopower and figure of merit taking into account the shift of the chemical
potential and the asymmetry of the density of states in the vicinity of the
Fermi surface. We show that the weak coupling between the grains leads to a
high thermopower and low thermal conductivity resulting in relatively high
values of the figure of merit on the order of one. We estimate the temperature
at which the figure of merit has its maximum value for two- and
three-dimensional samples. Our results are applicable for many emerging
materials, including artificially self-assembled nanoparticle arrays.Comment: 4 pages, 3 figure
From fat to FAT (CD36/SR-B2):Understanding the regulation of cellular fatty acid uptake
The molecular mechanisms underlying the cellular uptake of long-chain fatty acids and the regulation of this process have been elucidated in appreciable detail in the last decades. Two main players in this field, each discovered in the early 1990s, are (i) a membrane-associated protein first identified in adipose ('fat') tissue and referred to as putative fatty acid translocase (FAT)/CD36 (now officially designated as SR-B2) which facilitates the transport of fatty acids across the plasma membrane, and (ii) the family of transcription factors designated peroxisome proliferator-activated receptors (PPAR alpha, PPAR gamma, and PPAR(beta/delta) for which fatty acids and fatty acid metabolites are the preferred ligand. CD36/SR-B2 is the predominant membrane protein involved in fatty acid uptake into intestinal enterocytes, adipocytes and cardiac and skeletal myocytes. The rate of cellular fatty acid uptake is regulated by the subcellular vesicular recycling of CD36/SR-B2 from endosomes to the plasma membrane. Fatty acid-induced activation of PPARs results in the upregulation of the expression of genes encoding various proteins and enzymes involved in cellular fatty acid utilization. Both CD36/SR-B2 and the PPARs have been implicated in the derangements in fatty acid and lipid metabolism occurring with the development of pathophysiological conditions, such as high fat diet-induced insulin resistance and diabetic cardiomyopathy, and have been suggested as targets for metabolic intervention. In this brief review we discuss the discovery and current understanding of both CD36/SR-B2 and the PPARs in metabolic homeostasis. (C) 2016 Elsevier B.V. and Societe Francaise de Biochimie et Biologie Moleculaire (SFBBM). All rights reserved
Single grain heating due to inelastic cotunneling
We study heating effects of a single metallic quantum dot weakly coupled to
two leads. The dominant mechanism for heating at low temperatures is due to
inelastic electron cotunneling processes. We calculate the grain temperature
profile as a function of grain parameters, bias voltage, and time and show that
for nanoscale size grains the heating effects are pronounced and easily
measurable in experiments.Comment: 4 pages, 3 figures, revtex4, extended and corrected versio
The endocannabinoid system:Overview of an emerging multi-faceted therapeutic target
The endocannabinoids anandamide (AEA) and 2-arachidonoylglyerol (2-AG) are endogenous lipid mediators that exert protective roles in pathophysiological conditions, including cardiovascular diseases. In this brief review, we provide a conceptual framework linking endocannabinoid signaling to the control of the cellular and molecular hallmarks, and categorize the key components of endocannabinoid signaling that may serve as targets for novel therapeutics. The emerging picture not only reinforces endocannabinoids as potent regulators of cellular metabolism but also reveals that endocannabinoid signaling is mechanistically more complex and diverse than originally thought
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