2,050 research outputs found
Enforcing Intellectual Property Rights in Weak Appropriability Regimes: The Case of de Facto Protection Strategies in China
Pivotal Role of Reduced Glutathione in Oxygen-induced Regulation of the Na + /K + Pump in Mouse Erythrocyte Membranes
This study addresses the mechanisms of oxygen-induced regulation of ion transport pathways in mouse erythrocyte, specifically focusing on the role of cellular redox state and ATP levels. Mouse erythrocytes possess Na+/K+ pump, K+-Clâ and Na+-K+-2Clâ cotransporters that have been shown to be potential targets of oxygen. The activity of neither cotransporter changed in response to hypoxia-reoxygenation. In contrast, the Na+/K+ pump responded to hypoxic treatment with reversible inhibition. Hypoxia-induced inhibition was abolished in Na+-loaded cells, revealing no effect of O2 on the maximal operation rate of the pump. Notably, the inhibitory effect of hypoxia was not followed by changes in cellular ATP levels. Hypoxic exposure did, however, lead to a rapid increase in cellular glutathione (GSH) levels. Decreasing GSH to normoxic levels under hypoxic conditions abolished hypoxia-induced inhibition of the pump. Furthermore, GSH added to the incubation medium was able to mimic hypoxia-induced inhibition. Taken together these data suggest a pivotal role of intracellular GSH in oxygen-induced modulation of the Na+/K+ pump activit
The Impacts of Migration on Multidimensional Child Well-Being: Comparative Analysis Between Moldova and Georgia
Using novel household survey data collected between September 2011 and December 2012 on migrant- and non-migrant households in Moldova and Georgia, this paper proposes a method for measuring and comparing multidimensional child well-being in a migration context. While a growing body of literature addresses the effects of migration for children âleft behindâ, relatively few studies have empirically analysed if and to what extent migration implies different well-being outcomes for children. To compare the outcomes of children in current- and non-migrant households, the present paper defines a multidimensional well-being index comprised of six dimensions of wellness: education, material living standards, protection, physical health, emotional health, and communication access. The results of both bivariate and multivariate analysis suggest that migration bears limited consequences for different domains of well-being. In both Moldova and Georgia children in migrant households were found to have a slightly lower probability of attaining material well-being, but in Georgia migration was linked to higher probabilities of children attaining wellbeing in physical health, communication access, and on total index level. The results suggest that when migration has any statistically significant effect on child well-being, it is generally positive and relatively low in magnitude. The impacts of migration appear to differ widely between Moldova and Georgia, however. While migration was seen to have limited effect on the well-being of children in Moldova, it seemed to bear more consequences for children in Georgia, which likely reflects different migration trajectories, mobility patterns, and levels of maturity of each migration stream
A simple derivation of the effective stress coefficient for seismic velocities in porous rocks
Non-Markoffian effects of a simple nonlinear bath
We analyze a model of a nonlinear bath consisting of a single two-level
system coupled to a linear bath (a classical noise force in the limit
considered here). This allows us to study the effects of a nonlinear,
non-Markoffian bath in a particularly simple situation. We analyze the effects
of this bath onto the dynamics of a spin by calculating the decay of the
equilibrium correlator of the spin's z-component. The exact results are
compared with those obtained using three commonly used approximations: a
Markoffian master equation for the spin dynamics, a weak-coupling
approximation, and the substitution of a linear bath for the original nonlinear
bath.Comment: 7 pages, 6 figure
Quantum Dissipative Dynamics of the Magnetic Resonance Force Microscope in the Single-Spin Detection Limit
We study a model of a magnetic resonance force microscope (MRFM) based on the
cyclic adiabatic inversion technique as a high-resolution tool to detect single
electron spins. We investigate the quantum dynamics of spin and cantilever in
the presence of coupling to an environment. To obtain the reduced dynamics of
the combined system of spin and cantilever, we use the Feynman-Vernon influence
functional and get results valid at any temperature as well as at arbitrary
system-bath coupling strength. We propose that the MRFM can be used as a
quantum measurement device, i.e., not only to detect the modulus of the spin
but also its direction
The Brain at High Altitude: From Molecular Signaling to Cognitive Performance
The brain requires over one-fifth of the total body oxygen demand for normal functioning. At high altitude (HA), the lower atmospheric oxygen pressure inevitably challenges the brain, affecting voluntary spatial attention, cognitive processing, and attention speed after short-term, long-term, or lifespan exposure. Molecular responses to HA are controlled mainly by hypoxia-inducible factors. This review aims to summarize the cellular, metabolic, and functional alterations in the brain at HA with a focus on the role of hypoxia-inducible factors in controlling the hypoxic ventilatory response, neuronal survival, metabolism, neurogenesis, synaptogenesis, and plasticity
Myoglobin in Brown Adipose Tissue: A Multifaceted Player in Thermogenesis
Brown adipose tissue (BAT) plays an important role in energy homeostasis by generating heat from chemical energy via uncoupled oxidative phosphorylation. Besides its high mitochondrial content and its exclusive expression of the uncoupling protein 1, another key feature of BAT is the high expression of myoglobin (MB), a heme-containing protein that typically binds oxygen, thereby facilitating the diffusion of the gas from cell membranes to mitochondria of muscle cells. In addition, MB also modulates nitric oxide (NOâ˘) pools and can bind C16 and C18 fatty acids, which indicates a role in lipid metabolism. Recent studies in humans and mice implicated MB present in BAT in the regulation of lipid droplet morphology and fatty acid shuttling and composition, as well as mitochondrial oxidative metabolism. These functions suggest that MB plays an essential role in BAT energy metabolism and thermogenesis. In this review, we will discuss in detail the possible physiological roles played by MB in BAT thermogenesis along with the potential underlying molecular mechanisms and focus on the question of how BATâMB expression is regulated and, in turn, how this globin regulates mitochondrial, lipid, and NO⢠metabolism. Finally, we present potential MB-mediated approaches to augment energy metabolism, which ultimately could help tackle different metabolic disorders
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