525 research outputs found
Comparative Analysis of Control Techniques for PWM Rectifiers in Grid Connected Distributed Generation Systems Based on VOC and DPC
This paper presents Virtual flux based and Voltage based control schemes for PWM rectifiers in grid connected distributed generation systems from renewable sources are presented. In particular, the so-called Voltage Oriented Control (VOC), Direct Power Control (DPC), two DPC based techniques to minimize the Common Mode (CM) emissions called DPC-EMC1 and DPC-EMC2 set up by the authors and their versions based on virtual flux. All the described techniques have been implemented using MATLAB/Simulink® (Classic version 8.2 Release name (R2013b)) and compared with each other. Theoretical background with results of simulations is provided. The advantages and disadvantages of the individual control strategies are documented
Selective vulnerability of neurons to acute toxicity after proteasome inhibitor treatment: Implications for oxidative stress and insolubility of newly synthesized proteins
Maintaining protein homeostasis is vital to cell viability, with numerous studies demonstrating a role for proteasome inhibition occurring during the aging of a variety of tissues and, presumably, contributing to the disruption of cellular homeostasis during aging. In this study we sought to elucidate the differences between neurons and astrocytes in regard to basal levels of protein synthesis, proteasome-mediated protein degradation, and sensitivity to cytotoxicity after proteasome inhibitor treatment. In these studies we demonstrate that neurons have an increased vulnerability, compared to astrocyte cultures, to proteasome-inhibitor-induced cytotoxicity. No significant difference was observed between these two cell types in regard to the basal rates of protein synthesis, or basal rates of protein degradation, in the pool of short-lived proteins. After proteasome inhibitor treatment neuronal crude lysates were observed to undergo greater increases in the levels of ubiquitinated and oxidized proteins and selectively exhibited increased levels of newly synthesized proteins accumulating within the insoluble protein pool, compared to astrocytes. Together, these data suggest a role for increased oxidized proteins and sequestration of newly synthesized proteins in the insoluble protein pool, as potential mediators of the selective neurotoxicity after proteasome inhibitor treatment. The implications for neurons exhibiting increased sensitivity to acute proteasome inhibitor exposure, and the corresponding changes in protein homeostasis observed after proteasome inhibition, are discussed in the context of both aging and age-related disorders of the nervous system.Fil: Dasuri, Kalavathi. State University of Louisiana; Estados UnidosFil: Ebenezer, Philip J.. State University of Louisiana; Estados UnidosFil: Zhang, Le. State University of Louisiana; Estados UnidosFil: Fernandez Kim, Sun Ok. State University of Louisiana; Estados UnidosFil: Uranga, Romina Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Gavilán, Elena. State University of Louisiana; Estados UnidosFil: Di Blasio, Alessia. State University of Louisiana; Estados UnidosFil: Keller, Jeffrey N.. State University of Louisiana; Estados Unido
Amino acid analog toxicity in primary rat neuronal and astrocyte cultures: implications for protein misfolding and tdp-43 regulation
Amino acid analogs promote translational errors that result in aberrant protein synthesis, and have been used to understand the effects of protein misfolding in a variety of physiological and pathological settings. TDP-43 is a protein that is linked to protein aggregation and toxicity in a variety of neurodegenerative diseases. In this study we exposed primary rat neurons and astrocyte cultures to established amino acid analogs (Canavanine and Azetidine-2-carboxylic acid), and observed both cell types undergo a dose-dependent increase in toxicity, with neurons exhibiting a greater degree of toxicity as compared to astrocytes. Neurons and astrocytes exhibited similar increases in ubiquitinated and oxidized protein following analog treatment. Analog treatment increased Heat shock protein (Hsp) levels in both neurons and astrocytes. In neurons, and to a lesser extent astrocytes, the levels of TDP-43 increased in response to analog treatment. Taken together, these data indicate that neurons exhibit preferential toxicity and alterations in TDP-43, in response to increased protein misfolding, as compared to astrocytes
Crystal structure, superconductivity and magnetic properties of the superconducting ferromagnets Gd1.4-xDyxCe0.6Sr2RuCu2O10 (x=0 - 0.6)
The structural, electrical and magnetic properties of the superconducting
ferromagnets, Gd1.4-xDyxCe0.6Sr2RuCu2O10 (x=0-0.6) are systematically
investigated as a function of Dy doping and temperature. These compounds are
characterised by high temperature superconductivity (Tc ranging from 20-40 K
depending upon the Dy content) coexisting with weak ferromagnetism with two
magnetic transitions (TM2 ranging from 95-106 K and TM1 around 120 K). Doping
with Dy gives no significant structural changes except for a minor change in
the c/a ratio. However the superconducting transition temperature is
significantly suppressed and magnetic ordering temperature enhanced on Dy
doping. These effects are described and discussed.Comment: 21 pages, 6 figures, 1 tabl
Blue luminescence of Au nanoclusters embedded in silica matrix
Photoluminescence study using the 325 nm He-Cd excitation is reported for the
Au nanoclusters embedded in SiO2 matrix. Au clusters are grown by ion beam
mixing with 100 KeV Ar+ irradiation on Au [40 nm]/SiO2 at various fluences and
subsequent annealing at high temperature. The blue bands above ~3 eV match
closely with reported values for colloidal Au nanoclusters and supported Au
nanoislands. Radiative recombination of sp electrons above Fermi level to
occupied d-band holes are assigned for observed luminescence peaks. Peaks at
3.1 eV and 3.4 eV are correlated to energy gaps at the X- and L-symmetry
points, respectively, with possible involvement of relaxation mechanism. The
blue shift of peak positions at 3.4 eV with decreasing cluster size is reported
to be due to the compressive strain in small clusters. A first principle
calculation based on density functional theory using the full potential linear
augmented plane wave plus local orbitals (FP-LAPW+LO) formalism with
generalized gradient approximation (GGA) for the exchange correlation energy is
used to estimate the band gaps at the X- and L-symmetry points by calculating
the band structures and joint density of states (JDOS) for different strain
values in order to explain the blueshift of ~0.1 eV with decreasing cluster
size around L-symmetry point.Comment: 13 pages, 7 Figures Only in PDF format; To be published in J. of
Chem. Phys. (Tentative issue of publication 8th December 2004
Kayamanar's songs in Naritanai are the way to know the morals of life
Classical literature is the best literature depicting the antiquity of Tamil. They have the ability to convey the excellence and adaptation of human life. These literatures, instead of the elevation of life with matter, proved that the values of moral life could be spoken of by scholars and spread all over the world. The first of these classics, Natrinai, will be discussed in the essay on the principles of life sung by Kayamanar
S. Tamilselvan’s Short Story 'Subbuttai' from a Sociological Point of View
Among Tamil writers in the Karisal region, S. Tamilselvan's story, Subhuthai, is said to point to the plight of child labor. The Subhuthai story points to the psychological tendency of a child to express her emotional state in a realistic way while carrying the burden of the family at the age of going to school, and thinking of her mother and the baby in her arms, without talking about education at all. No matter how many short stories have been written about child labor in the history of Tamil short stories, this story highlights the plight of child labor, which is considered a disgrace to society. His story has done an unparalleled job of convincing the upper class through such stories to stop the children working at their homes and send them to school. Another important domain in the works of Tamilselvan are the stories of Subbuthai, Voices, Lunger Boy, Word, and Mynakkal, which tell us about the mental world of children, the stories of the nostalgic crises of children from economically disadvantaged families. Through Subhuthai, the expressions of Karisal children’s lifestyle is said to be voiced
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