Identifying the cellular targets of drug action in the central nervous system following corticosteroid therapy

Corticosteroid (CS) therapy is used widely in the treatment of a range of pathologies, but can delay production of myelin, the insulating sheath around central nervous system nerve fibers. The cellular targets of CS action are not fully understood, that is, "direct" action on cells involved in myelin genesis [oligodendrocytes and their progenitors the oligodendrocyte precursor cells (OPCs)] versus "indirect" action on other neural cells. We evaluated the effects of the widely used CS dexamethasone (DEX) on purified OPCs and oligodendrocytes, employing complementary histological and transcriptional analyses. Histological assessments showed no DEX effects on OPC proliferation or oligodendrocyte genesis/maturation (key processes underpinning myelin genesis). Immunostaining and RT-PCR analyses show that both cell types express glucocorticoid receptor (GR; the target for DEX action), ruling out receptor expression as a causal factor in the lack of DEX-responsiveness. GRs function as ligand-activated transcription factors, so we simultaneously analyzed DEX-induced transcriptional responses using microarray analyses; these substantiated the histological findings, with limited gene expression changes in DEX-treated OPCs and oligodendrocytes. With identical treatment, microglial cells showed profound and global changes post-DEX addition; an unexpected finding was the identification of the transcription factor Olig1, a master regulator of myelination, as a DEX responsive gene in microglia. Our data indicate that CS-induced myelination delays are unlikely to be due to direct drug action on OPCs or oligodendrocytes, and may occur secondary to alterations in other neural cells, such as the immune component. To the best of our knowledge, this is the first comparative molecular and cellular analysis of CS effects in glial cells, to investigate the targets of this major class of anti-inflammatory drugs as a basis for myelination deficits

Intersecting D4-branes Model of Holographic QCD and Tachyon Condensation

We consider the intersecting D4-brane and anti-D4-brane model of holographic QCD, motivated by the model that has recently been suggested by Van Raamsdonk and Whyte. We analyze such D4-branes by the use of the action with a bi-fundamental ``tachyon'' field, so that we find the classical solutions describing the intersecting D4-branes and the U-shaped D4-branes. We show that the ``tachyon'' field in the bulk theory provides a current quark mass and a quark condensate to the dual gauge theory and that the lowest modes of mesons obtain mass via tachyon condensation. Then evaluating the properties of a pion, one can reproduce Gell-Mann-Oakes-Renner relation.Comment: 24 pages, 5 figures; v2: refs. added; v3: discussions on Chern-Simons terms are adde

Multilevel Inverter by using Switching Capacitor in PV Grid

Abstract: In this paper, we are using multilevel inverter by using switching capacitor for PV grid. Now a day's multilevel inverters have become more popular over the years in electric high power application with the promise of less disturbances and the possibility to function at lower switching frequencies than ordinary two-level inverters. So by cascading multilevel inverter the output voltage will be increases. By using multilevel inverter the cost will be less. It will be required less space. Modulation strategies, component comparison and solutions to the multilevel voltage source balancing problem will also be presented in this work. By using the multilevel inverter we can reduce the total harmonic distraction compare to the other sources in PV grid for DC to AC converter. The proposed method is simulated in Matlab Simulink

Graviton 1-loop partition function for 3-dimensional massive gravity

The graviton 1-loop partition function in Euclidean topologically massive gravity (TMG) is calculated using heat kernel techniques. The partition function does not factorize holomorphically, and at the chiral point it has the structure expected from a logarithmic conformal field theory. This gives strong evidence for the proposal that the dual conformal field theory to TMG at the chiral point is indeed logarithmic. We also generalize our results to new massive gravity.Comment: 19 pages, v2: major revision, considerably stronger conclusions, added comparison with LCFT partition function, confirmation of LCFT conjecture, added autho

Analysis of DSTATCOM for PV Based Micro Grid

Abstract: As the power demand is increasing in India the PV grid is playing important role in power distribution the main problem in PV based microgrid is power quality problem In this paper proposes a new method to generate reference voltage for overcome harmonic in line voltage the a distribution static compensator (DSTATCOM) operating in PV based micro grid. The proposed method ensures that nearly unity power factor (UPF) is attained at the load terminal during nominal operation. Also the compensator injects lower currents and therefore reduces losses in the feeder. The rating of DSTATCOM is achieved which will improve the quality of voltage by to mitigate voltage sag and swell. In this paper we analysis DSTATCOM for PV grid in MATLAB simulation. Keywords: Power quality (PQ), micro grid, DSTATCOM, voltage control, PI controller. I.) INTRODUCTION In recent years the PV based micro grid has been growing due to its several potential and economic advantages like, the microgrid has small investment. The micro-grid has less energy losses and higher overall energy efficiency. The micro-grid is designed based on the renewable energy sources near by the Load. The fuel cells and PV cell technology are mainly used in the micro grid to full-fill the load demand with hybrid technology. In hybrid micro-grid the power quality problem is the measures aspect, which is affecting the load demand. The main reason of power quality problem is power electronic components, which necessary in micro grid to convert dc to ac. The output of the inverter in micro grid should be compatible in voltage and frequency with load. In ac micro-grid dc power from photovoltaic panels has been converted into ac using dc/dc boosters and dc/ac inverter in order to connect the ac load. Due to static devices in converter results are harmonics injection and lower power factor to electric power system. The load equipment's of the modern generation are additional sensitive. Due to harmonics can initiate production loss, financial loss and environmental effect. A Distribution system suffers from current as well as voltage-related power-quality (PQ) problems, which include poor power factor, distorted source current, and voltage disturbances A DSTATCOM [1] connected at the point of common coupling (PCC), II.) DSTATCOM Power quality (PQ) in distribution systems affects is a measure of deviations in voltage, current, frequency of a specific system and associated component

Mucosal Application of gp140 Encoding DNA Polyplexes to Different Tissues Results in Altered Immunological Outcomes in Mice

Increasing evidence suggests that mucosally targeted vaccines will enhance local humoral and cellular responses whilst still eliciting systemic immunity. We therefore investigated the capacity of nasal, sublingual or vaginal delivery of DNA-PEI polyplexes to prime immune responses prior to mucosal protein boost vaccination. Using a plasmid expressing the model antigen HIV CN54gp140 we show that each of these mucosal surfaces were permissive for DNA priming and production of antigen-specific antibody responses. The elicitation of systemic immune responses using nasally delivered polyplexed DNA followed by recombinant protein boost vaccination was equivalent to a systemic prime-boost regimen, but the mucosally applied modality had the advantage in that significant levels of antigen-specific IgA were detected in vaginal mucosal secretions. Moreover, mucosal vaccination elicited both local and systemic antigen-specific IgG(+) and IgA(+) antibody secreting cells. Finally, using an Influenza challenge model we found that a nasal or sublingual, but not vaginal, DNA prime/protein boost regimen protected against infectious challenge. These data demonstrate that mucosally applied plasmid DNA complexed to PEI followed by a mucosal protein boost generates sufficient antigen-specific humoral antibody production to protect from mucosal viral challenge

Chern-Simons black holes: scalar perturbations, mass and area spectrum and greybody factors

We study the Chern-Simons black holes in d-dimensions and we calculate analytically the quasi-normal modes of the scalar perturbations and we show that they depend on the highest power of curvature present in the Chern-Simons theory. We obtain the mass and area spectrum of these black holes and we show that they have a strong dependence on the topology of the transverse space and they are not evenly spaced. We also calculate analytically the reflection and transmission coefficients and the absorption cross section and we show that at low frequency limit there is a range of modes which contributes to the absorption cross section.Comment: 19 pages, 18 figures, the title has been changed to reflect the addition of an another section on the reflection, transmission coefficients and absorption cross sections of the Chern-Simons black holes. Version to be published in JHE

Orbital Kondo effect in carbon nanotubes

Progress in the fabrication of nanometer-scale electronic devices is opening new opportunities to uncover the deepest aspects of the Kondo effect, one of the paradigmatic phenomena in the physics of strongly correlated electrons. Artificial single-impurity Kondo systems have been realized in various nanostructures, including semiconductor quantum dots, carbon nanotubes and individual molecules. The Kondo effect is usually regarded as a spin-related phenomenon, namely the coherent exchange of the spin between a localized state and a Fermi sea of electrons. In principle, however, the role of the spin could be replaced by other degrees of freedom, such as an orbital quantum number. Here we demonstrate that the unique electronic structure of carbon nanotubes enables the observation of a purely orbital Kondo effect. We use a magnetic field to tune spin-polarized states into orbital degeneracy and conclude that the orbital quantum number is conserved during tunneling. When orbital and spin degeneracies are simultaneously present, we observe a strongly enhanced Kondo effect, with a multiple splitting of the Kondo resonance at finite field and predicted to obey a so-called SU(4) symmetry.Comment: 26 pages, including 4+2 figure

Generalised massive gravity one-loop partition function and AdS/(L)CFT

The graviton 1-loop partition function is calculated for Euclidean generalised massive gravity (GMG) using AdS heat kernel techniques. We find that the results fit perfectly into the AdS/(L)CFT picture. Conformal Chern-Simons gravity, a singular limit of GMG, leads to an additional contribution in the 1-loop determinant from the conformal ghost. We show that this contribution has a nice interpretation on the conformal field theory side in terms of a semi-classical null vector at level two descending from a primary with conformal weights (3/2,-1/2).Comment: 25 p., 2 jpg figs, v2: added 6 lines of clarifying text after Eq. (2.38