モエノマイシンとバンコマイシンの感受性に影響する黄色ブドウ球菌の因子に関する研究

広島大学(Hiroshima University)博士(歯学)Dentistrydoctora

H_2 Line Emission Associated with the Formation of the First Stars

Molecular hydrogen line radiation emitted in formation events of first-generation stars are evaluated in a discussion of its detectability by future observational facilities. H_2 luminosity evolution from the onset of prestellar collapse until the formation of a \sim 100 M_{\odot} protostar is followed. Calculations are extended not only to the early phase of the runaway collapse but also to the later phase of accretion, whose observational features have not been studied before. Contrary to the runaway collapse phase, where the pure-rotational lines are always dominant, in the accretion phase rovibrational line emission becomes prominent. The maximum luminosity is also attained in the accretion phase for strong emission lines. The peak intensity of the strongest rovibrational line reaches \sim 10^{-29} (W/m^2), corresponding to the flux density of 10^{-5} (\mu Jy), for a source at the typical redshift of first-generation star formation, 1+z=20. Although the redshifted rovibrational H_2 emission from such an epoch falls in the wavelength range of the next-generation infrared satellite, Space Infrared Telescope for Cosmology and Astrophysics, for exceeding the detection threshold 10^7 such protostars are required to reach the maximum luminosity simultaneously in a pregalactic cloud. It is improbable that this condition is satisfied in a realistic scenario of early structure formation.Comment: 16 pages, 5 figures, accepted by PAS

How Viscous Is the Solidlike Structure at the Interface of Ionic Liquids? A Study Using Total Internal Reflection Fluorescence Spectroscopy with a Fluorescent Molecular Probe Sensitive to High Viscosity

Aiming at the evaluation of the viscosity of the interfacial solidlike structure of ionic liquids (ILs), we performed total internal reflection fluorescence (TIRF) spectroscopy for N, N-diethyl-N′-phenyl-rhodamine (Ph-DER), a fluorescent probe that is sensitive to viscosity in a high-viscosity range. TIRF spectra at the glass interface of trioctylmethylammonium bis(nonafluorobutanesulfonyl)amide (TOMAC4C4N), a hydrophobic IL, showed that the fluorescence intensity of Ph-DER increases with the decrease of the evanescence penetration depth, suggesting that there exists a high-viscosity region at the interface. In contrast, glycerol, which is a molecular liquid with a bulk viscosity similar to that of TOMAC4C4N, did not show such a fluorescence increase, supporting that the formation of a highly viscous solidlike structure at the interface is intrinsic to ILs. A model analysis suggested that the high viscous region at the glass interface of TOMAC4C4N is at least twice thicker than the ionic multilayers at the air interface, implying that the solid substrate enhances the ordering of the interfacial structure of ILs. The viscosity at the glass interface of TOMAC4C4N was found to be at least 40 times higher than that of the liquid bulk

Magnetic Field-Induced Superconductor-Insulator-Metal Transition in an Organic Conductor: An Infrared Magneto-Optical Imaging Spectroscopy

The magnetic field-induced superconductor-insulator-metal transition (SIMT) in partially deuterated $\kappa$-(BEDT-TTF)$_2$Cu[N(CN)$_2$]Br, which is just on the Mott boundary, has been observed using the infrared magneto-optical imaging spectroscopy. The infrared reflectivity image on the sample surface revealed that the metallic (or superconducting) and insulating phases coexist and they have different magnetic field dependences. One of the magnetic field dependence is SIMT that appeared on part of the sample surface. The SIMT was concluded to originate from the balance of the inhomogenity in the sample itself and the disorder of the ethylene end groups resulting from fast cooling.Comment: 5 pages, 5 figures, to appear in Phys. Rev.

Expression of anti-fungal peptide, β-defensin 118 in oral fibroblasts induced by C. albicans β-glucan-containing particles

Objective: Although oral fibroblasts are thought to have the potential to enhance host defenses against Candida albicans , it is unknown whether they are able to recognize Candida cell components to increase the expression of antifungal peptides, such as defensin factors, against Candida infection. Methodology: We performed expression profiles of defensin genes induced by heat-killed C. albicans in oral immortalized fibroblasts (GT1) using cDNA microarray analysis. From those results, quantitative RT-PCR was used to examine the effects of Candida β-glucan-containing particles (β-GPs) on β-Defensin 118 (DEFB 118) expression in oral mucosal cells. Furthermore, the antifungal activities of recombinant DEFB 118 against C. albicans and C. glabrata were investigated using fungicidal assays. Results: Microarray analysis showed that DEFB118, β-Defensin 129 (DEFB129), and α-Defensin 1 (DEFA1) genes were induced by heat-killed C. albicans and that their mRNA expressions were also significantly increased by live as well as heat-killed C. albicans . Next, we focused on DEFB118, and found that GT1, primary fibroblasts, and RT7 (oral immortalized keratinocytes) constitutively expressed DEFB118 mRNA expression in RT-PCR. Furthermore, C. albicans β-GPs significantly increased the expression of DEFB118 mRNA in GT1 and primary fibroblasts. Although DEFB118 mRNA expression in RT7 was significantly induced by both live and heat-killed C. albicans, C. albicans β-GPs failed to have an effect on that expression. Finally, recombinant DEFB118 significantly decreased the survival of both strains of C. albicans in a dose-dependent manner, whereas no effects were seen for both C. glabrata strains. Conclusion: DEFB118, induced by C. albicans β-GPs from oral fibroblasts, may play an important role in oral immune responses against C. albicans infection

Relation between Prolonged Sedentary Bouts and Health-Related Quality of Life in Patients on Chronic Hemodialysis

This study aimed to investigate the link between prolonged sedentary bouts and health-related quality of life (QOL) in patients on chronic hemodialysis (CHD). A total of 84 outpatients on CHD, aged 71.6±11.8 years, were enrolled in this cross-sectional study. Parameters for prolonged sedentary bouts [i.e., ≧ 30 min (% and bout) and ≧ 60 min (% and bout)] were measured using a triaxial accelerometer. Health-related QOL (HRQOL) was evaluated by the Euro-QOL (EQ-5D). Clinical parameters were obtained from medical records. Relatively prolonged sedentary bouts (%) were 44.0±18.2 (≧ 30 min) and 29.8±16.5 (≧ 60 min) for total days. Prolonged sedentary bouts (bouts) were 6.2±2.7 (≧ 30 min) and 2.7±1.6 (≧ 60 min) for total days. EQ-5D scores were 0.728±0.220. All prolonged sedentary bout parameters were negatively correlated with EQ-5D scores, except for prolonged sedentary bouts (≧ 60 min) (min) and relatively prolonged sedentary bouts (%) on hemodialysis days. Multiple regression analysis showed that prolonged sedentary bout parameters were an important factor in EQ-5D scores even after adjusting for confounding factors for total and non-hemodialysis days. Our results suggested that prolonged sedentary bouts were closely associated with HRQOL in patients on CHD, especially on non-hemodialysis days

Effects of CEACAM1 in oral keratinocytes on HO-1 expression induced by Candida β-glucan particles

Objective: Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) is a member of the carcinoembryonic antigen family. Although its expression has been found in chronic oral inflammatory epithelium, this study aimed to know whether CEACAM1 in oral keratinocytes participates in host immune response against Candida albicans . Methodology: We investigated CEACAM1 expression in oral keratinocytes induced by C. albicans as well as by Candida cell wall component β-glucan particles (β-GPs). Furthermore, the effects of CEACAM1 on β-GPs-induced heme oxygenase-1 (HO-1) expression and its related signals were examined. Results: Fluorescence staining showed CEACAM1 expression in oral keratinocytes (RT7) cells, whereas quantitative reverse transcription (RT)-PCR indicated that both live and heat-killed C. albicans increased CEACAM1 mRNA expression in RT7 cells. Examinations using quantitative RT-PCR and western blotting indicated that CEACAM1 expression was also increased by β-GPs derived from C. albicans . Specific siRNA for CEACAM1 decreased HO-1 expression induced by β-GPs from C. albicans as well as the budding yeast microorganism Saccharomyces cerevisiae . Moreover, knockdown of CEACAM1 decreased β-GPs-induced ROS activity in the early phase and translocation of Nrf2 into the nucleus. Conclusion: CEACAM1 in oral keratinocytes may have a critical role in regulation of HO-1 for host immune defense during Candida infection

Relationship between Sedentary Behavior and All-cause Mortality in Japanese Chronic Hemodialysis Patients: A Prospective Cohort Study

We investigated the relationship between sedentary behavior and all-cause mortality in patients undergoing hemodialysis. A total of 71 patients (39 men, 32 women, aged 72.1±11.7 years) were enrolled in this longitudinal study. Their sedentary behavior was measured using a tri-accelerometer that provides relative values per daily wearing time. We classified the sedentary behavior time into 2 groups (under the median: short-sedentary behavior (SB) group; over the median: long-SB group) and compared the groups’ clinical parameters. We compared the groups’ survival rates by using Kaplan-Meier curves and the log-rank test, and we performed multivariate analyses by a Cox-proportional hazard model to evaluate the relationship between the sedentary behavior and the survival rate. Twenty patients (28.2%) died during the observation period. The survival rate of the short-SB group was significantly higher than that of the long-SB group. Sedentary behavior was thus an important factor for all-cause mortality even after adjusting for confounding factors by a Cox-proportional hazard model. Sedentary behavior is closely linked to all-cause mortality, especially total days and non-hemodialysis days, and reducing sedentary behavior may be beneficial to reduce the all-cause mortality of patients on chronic hemodialysis