Effect of Holstein phonons on the optical conductivity of gapped graphene

We study the optical conductivity of a doped graphene when a sublattice symmetry breaking is occurred in the presence of the electron-phonon interaction. Our study is based on the Kubo formula that is established upon the retarded self-energy. We report new features of both the real and imaginary parts of the quasiparticle self-energy in the presence of a gap opening. We find an analytical expression for the renormalized Fermi velocity of massive Dirac Fermions over broad ranges of electron densities, gap values and the electron-phonon coupling constants. Finally we conclude that the inclusion of the renormalized Fermi energy and the band gap effects are indeed crucial to get reasonable feature for the optical conductivity.Comment: 12 pages, 4 figures. To appear in Eur. Phys. J.

Kir4.1 channels contribute to astrocyte CO2/H+-sensitivity and the drive to breathe

Astrocytes in the retrotrapezoid nucleus (RTN) stimulate breathing in response to CO2/H+, however, it is not clear how these cells detect changes in CO2/H+. Considering Kir4.1/5.1 channels are CO2/H+-sensitive and important for several astrocyte-dependent processes, we consider Kir4.1/5.1 a leading candidate CO2/H+ sensor in RTN astrocytes. To address this, we show that RTN astrocytes express Kir4.1 and Kir5.1 transcripts. We also characterized respiratory function in astrocyte-specific inducible Kir4.1 knockout mice (Kir4.1 cKO); these mice breathe normally under room air conditions but show a blunted ventilatory response to high levels of CO2, which could be partly rescued by viral mediated re-expression of Kir4.1 in RTN astrocytes. At the cellular level, astrocytes in slices from astrocyte-specific inducible Kir4.1 knockout mice are less responsive to CO2/H+ and show a diminished capacity for paracrine modulation of respiratory neurons. These results suggest Kir4.1/5.1 channels in RTN astrocytes contribute to respiratory behavior

OX40 Gene Expression and its Serum Levels in New Cases of Patients with Multiple Sclerosis

BACKGROUND: Multiple sclerosis (MS) is an autoimmune disease of human central nervous system (CNS). OX40 (CD134) is a member of the tumor necrosis factor (TNF) receptor family. Ligation of OX40 is crucial for clonal expansion of antigen-specific T-cells as well as survival and generation of T-cell memory. Soluble OX40 is the soluble form of OX40 and it has been demonstrated that it is correlated with some autoimmune disorders. OBJECTIVES: The purpose of this study was to investigate serum levels and gene expression of OX40 as a paraclinical marker in MS patients compared to the healthy control group. METHODS: In this research, 40 new cases of MS patients and 40 healthy people as control group were investigated. After extracting RNA from peripheral blood and cDNA synthesis, we examined gene expression using real-time PCR technique, and serum level of soluble OX40 was measured by commercially available ELISA kit. Additionally, Mann-Whitney test was used to compare the gene expression and serum levels between two groups. RESULTS: We did not find any significant correlation between OX40 gene expression and MS disease (p=0.715). Soluble OX40 serum levels of MS patients were not significantly different from the control group (P=0.409). CONCLUSIONS: According to the results of the current study, expression of OX40 gene as an inflammatory factor in peripheral blood and also serum levels of OX40 could not be considered paraclinical markers of this disease. © 2018 - IOS Press and the authors. All rights reserved

OX40 Gene Expression and its Serum Levels in New Cases of Patients with Multiple Sclerosis

BACKGROUND: Multiple sclerosis (MS) is an autoimmune disease of human central nervous system (CNS). OX40 (CD134) is a member of the tumor necrosis factor (TNF) receptor family. Ligation of OX40 is crucial for clonal expansion of antigen-specific T-cells as well as survival and generation of T-cell memory. Soluble OX40 is the soluble form of OX40 and it has been demonstrated that it is correlated with some autoimmune disorders. OBJECTIVES: The purpose of this study was to investigate serum levels and gene expression of OX40 as a paraclinical marker in MS patients compared to the healthy control group. METHODS: In this research, 40 new cases of MS patients and 40 healthy people as control group were investigated. After extracting RNA from peripheral blood and cDNA synthesis, we examined gene expression using real-time PCR technique, and serum level of soluble OX40 was measured by commercially available ELISA kit. Additionally, Mann-Whitney test was used to compare the gene expression and serum levels between two groups. RESULTS: We did not find any significant correlation between OX40 gene expression and MS disease (p=0.715). Soluble OX40 serum levels of MS patients were not significantly different from the control group (P=0.409). CONCLUSIONS: According to the results of the current study, expression of OX40 gene as an inflammatory factor in peripheral blood and also serum levels of OX40 could not be considered paraclinical markers of this disease. © 2018 - IOS Press and the authors. All rights reserved