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Search Results: 1 - 10 of 1276 matches for " Nobuhiko Okada "
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Analysis of Magnetic Field-Angle Dependent Electronic Raman Scattering to Probe the Superconducting Gap
Masaru Okada,Nobuhiko Hayashi
Physics , 2013, DOI: 10.7566/JPSCP.3.015045
Abstract: We study the field-angle resolved electronic Raman scattering in 2-dimensional d-wave superconducting vortex states theoretically by quasi-classical approximation, the so-called Doppler-shift method. An analytic expression is obtained for the field angle dependence of the Raman scattering amplitude at zero temperature. After numerical integration, we obtain the scattering intensity for various field angles by changing the Raman shift energy. Field-angle resolved electronic Raman scattering turns out to be an effective method for probing unconventional superconducting gap structures. It shows a novel phenomenon: reversal of extrema as a function of frequency without changing temperature or field magnitude.
Functional Characterization of the Type III Secretion ATPase SsaN Encoded by Salmonella Pathogenicity Island 2
Yukie Yoshida, Tsuyoshi Miki, Sayaka Ono, Takeshi Haneda, Masahiro Ito, Nobuhiko Okada
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0094347
Abstract: A type III secretion system (T3SS) is utilized by a large number of gram-negative bacteria to deliver effectors directly into the cytosol of eukaryotic host cells. One essential component of a T3SS is an ATPase that catalyzes the unfolding of proteins, which is followed by the translocation of effectors through an injectisome. Here we demonstrate a functional role of the ATPase SsaN, a component of Salmonella pathogenicity island 2 T3SS (T3SS-2) in Salmonella enterica serovar Typhimurium. SsaN hydrolyzed ATP in vitro and was essential for T3SS function and Salmonella virulence in vivo. Protein-protein interaction analyses revealed that SsaN interacted with SsaK and SsaQ to form the C ring complex. SsaN and its complex co-localized to the membrane fraction under T3SS-2 inducing conditions. In addition, SsaN bound to Salmonella pathogenicity island 2 (SPI-2) specific chaperones, including SsaE, SseA, SscA, and SscB that facilitated translocator/effector secretion. Using an in vitro chaperone release assay, we demonstrated that SsaN dissociated a chaperone-effector complex, SsaE and SseB, in an ATP-dependent manner. Effector release was dependent on a conserved arginine residue at position 192 of SsaN, and this was essential for its enzymatic activity. These results strongly suggest that the T3SS-2-associated ATPase SsaN contributes to T3SS-2 effector translocation efficiency.
Interobserver variation in the endoscopic diagnosis of gastroduodenal ulcer scars: implications for clinical management of NSAIDs users
Yuji Amano, Goichi Uno, Takafumi Yuki, Mayumi Okada, Yasumasa Tada, Nobuhiko Fukuba, Norihisa Ishimura, Shunji Ishihara, Yoshikazu Kinoshita
BMC Research Notes , 2011, DOI: 10.1186/1756-0500-4-409
Abstract: The first study enrolled 200 consecutive patients with a clinical history of gastric or duodenal ulcers previously confirmed by esophagogastroduodenoscopy. The sensitivity of endoscopy for identifying scars was determined for these patients. In the second study, the extent of interobserver agreement was determined for 47 endoscopists who identified ulcer scars in endoscopic photographs of 30 sites of previous active gastric ulcers and 30 sites of previous active duodenal ulcers. The kappa coefficient of reliability was calculated to measure the interobserver agreement on the diagnosis of ulcer scars.Out of 190 patients eligible for analysis, 104 (54.7%) were found to have gastric or duodenal ulcer scars on endoscopy; there were no gastric or duodenal ulcer scars seen in the remaining patients (45%). In the second study, the kappa values for endoscopic diagnosis of gastric and duodenal ulcer scars were 0.14 (95% CI 0.13-0.16) and 0.29 (95% CI 0.27-0.32), respectively. The addition of indigo-carmine chromoendoscopy did not provide a statistically significant improvement in diagnostic concordance in patients with gastric ulcer scar since the kappa value for chromoendoscopic diagnosis was 0.15; 95% CI 0.13-0.17 as low as for un-contrasted scars.The sensitivity and concordance of endoscopic diagnosis of gastric and duodenal ulcer scars are not satisfactory for the use of endoscopy only to identify previous ulcer disease. To avoid the overlooking the previous clinical history of peptic ulcer diseases, the diagnosis of peptic ulcer scar has to be carefully done prior to NSAIDs administration.Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely prescribed and have become increasingly associated with adverse gastroduodenal events [1,2]. Gastric and duodenal ulcers have been reported to be found in as high as 17% of chronic NSAIDs users and 12% of low-dose aspirin (LDA) users. Coadministration of proton pump inhibitors (PPIs) reduces the proportion of gastric and duodenal
Transposon Mutagenesis of Probiotic Lactobacillus casei Identifies asnH, an Asparagine Synthetase Gene Involved in Its Immune-Activating Capacity
Masahiro Ito, Yun-Gi Kim, Hirokazu Tsuji, Takuya Takahashi, Mayumi Kiwaki, Koji Nomoto, Hirofumi Danbara, Nobuhiko Okada
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0083876
Abstract: Lactobacillus casei ATCC 27139 enhances host innate immunity, and the J1 phage-resistant mutants of this strain lose the activity. A transposon insertion mutant library of L. casei ATCC 27139 was constructed, and nine J1 phage-resistant mutants out of them were obtained. Cloning and sequencing analyses identified three independent genes that were disrupted by insertion of the transposon element: asnH, encoding asparagine synthetase, and dnaJ and dnaK, encoding the molecular chaperones DnaJ and DnaK, respectively. Using an in vivo mouse model of Listeria infection, only asnH mutant showed deficiency in their ability to enhance host innate immunity, and complementation of the mutation by introduction of the wild-type asnH in the mutant strain recovered the immuno-augmenting activity. AsnH protein exhibited asparagine synthetase activity when the lysozyme-treated cell wall extracts of L. casei ATCC 27139 was added as substrate. The asnH mutants lost the thick and rigid peptidoglycan features that are characteristic to the wild-type cells, indicating that AsnH of L. casei is involved in peptidoglycan biosynthesis. These results indicate that asnH is required for the construction of the peptidoglycan composition involved in the immune-activating capacity of L. casei ATCC 27139.
Friendship Motivation, Aggression, and Self-Esteem in Japanese Undergraduate Students  [PDF]
Ryo Okada
Psychology (PSYCH) , 2012, DOI: 10.4236/psych.2012.31002
Abstract: The purpose of this study was to examine the relationship among self-determined friendship motivation (motivation for friendship formation), aggression, and self-esteem in a sample of 262 Japanese university students. The hypothetical model posited that self-determined friendship motivation predicted lower levels of aggression, which, in turn, predicted lower levels of self-esteem. The results showed that self-determined friendship motivation predicted lower levels of anger, hostility, and physical aggression and that hostility and anger predicted lower levels of self-esteem. Verbal aggression was found to be positively associated with self-determined friendship motivation and self-esteem. The different relationships between self-determined friendship motivation and each facet of aggression are discussed.
Comparative proteomic analysis of Salmonella enterica serovar Typhimurium ppGpp-deficient mutant to identify a novel virulence protein required for intracellular survival in macrophages
Takeshi Haneda, Mariko Sugimoto, Yukie Yoshida-Ohta, Yoshio Kodera, Masamichi Oh-Ishi, Tadakazu Maeda, Satomi Shimizu-Izumi, Tsuyoshi Miki, Yoshinori Kumagai, Hirofumi Danbara, Nobuhiko Okada
BMC Microbiology , 2010, DOI: 10.1186/1471-2180-10-324
Abstract: Of the 366 examined spots, 269 proteins were successfully identified. The comparative analysis of the wild-type and ppGpp0 mutant strains revealed 55 proteins, the expression patterns of which were affected by ppGpp. Using a mouse infection model, we further identified a novel virulence-associated factor, STM3169, from the ppGpp-regulated and Salmonella-specific proteins. In addition, Salmonella strains carrying mutations in the gene encoding STM3169 showed growth defects and impaired growth within macrophage-like RAW264.7 cells. Furthermore, we found that expression of stm3169 was controlled by ppGpp and SsrB, a response regulator of the two-component system located on Salmonella pathogenicity island 2.A proteomic approach using a 2-DE reference map can prove a powerful tool for analyzing virulence factors and the regulatory network involved in Salmonella pathogenesis. Our results also provide evidence of a global response mediated by ppGpp in S. enterica.The facultative intracellular bacterium Salmonella enterica causes a broad spectrum of diseases, such as gastroenteritis and bacteremia, which are typically acquired by oral ingestion of contaminated food or water. S. enterica serovar Typhimurium (S. Typhimurium) causes enterocolitis in humans and a typhoid-like systemic infection in mice.Several virulence genes associated with Salmonella pathogenicity islands (SPIs) and the virulence plasmid have been characterized in S. Typhimurium. Two type III secretion systems (T3SS) encoded by SPI-1 and SPI-2 play central roles in Salmonella pathogenesis. SPI-1 is essential for the invasion of host cells and the induction of apoptosis in infected macrophages [1,2]. SPI-2 T3SS primarily confers survival and replication on macrophages and is required for systemic infection in the mouse infection model [3,4]. Expression of SPI-2 genes is induced within a modified phagosome, called the Salmonella-containing vacuole (SCV), in infected macrophages [5]. Induction of SPI-2 genes dep
Increased Red Blood Cell Distribution Width Associates with Cancer Stage and Prognosis in Patients with Lung Cancer
Yasuko Koma, Akira Onishi, Hirofumi Matsuoka, Nao Oda, Naoya Yokota, Yusuke Matsumoto, Midori Koyama, Nobuhiko Okada, Nariyasu Nakashima, Daiki Masuya, Harukazu Yoshimatsu, Yujiro Suzuki
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0080240
Abstract: Background Red cell distribution width (RDW), one of many routinely examined parameters, shows the heterogeneity in erythrocyte size. We investigated the association of RDW levels with clinical parameters and prognosis of lung cancer patients. Methods Clinical and laboratory data from 332 patients with lung cancer in a single institution were retrospectively studied by univariate analysis. Kaplan-Meier survival analysis and Cox proportional hazard models were used to examine the effect of RDW on survival. Results The RDW levels were divided into two groups: high RDW (>=15%), n=73 vs. low RDW, n=259 (<15%). Univariate analysis showed that there were significant associations of high RDW values with cancer stage, performance status, presence of other disease, white blood cell count, hemoglobin, mean corpuscular volume, platelet count, albumin level, C-reactive protein level, and cytokeratin 19 fragment level. Kruskal-Wallis tests revealed an association of RDW values with cancer stage in patients irrespective of comorbidity (patient with/without comorbidity: p<0.0001, patient without comorbidity: p<0.0001). Stages I-IV lung cancer patients with higher RDW values had poorer prognoses than those with lower RDW values (Wilcoxon test: p=0.002). In particular, the survival rates of stage I and II patients (n=141) were lower in the high RDW group (n=19) than in the low RDW group (n=122) (Wilcoxon test: p<0.001). Moreover, multivariate analysis showed higher RDW is a significant prognostic factor (p=0.040). Conclusion RDW is associated with several factors that reflect inflammation and malnutrition in lung cancer patients. Moreover, high levels of RDW are associated with poor survival. RDW might be used as a new and convenient marker to determine a patient’s general condition and to predict the mortality risk of lung cancer patients.
Universal and Nonuniversal Dynamical Conductivity in Small Metallic Grains: An Ambivalent Role of T-Invariance at Finite Frequency
Nobuhiko Taniguchi
Journal of Probability and Statistics , 2010, DOI: 10.1155/2010/751395
Abstract: The idea of random matrix theory is applicable not only to the level statistics but also to various physical observables. Taking the dynamical conductivity in isolated quantum dots with diffusive dynamics, we investigate analytically intertwining effects of the time-reversal invariance, level repulsion and quantum interference. We clarify an ambivalent role of the time-reversal invariance at finite frequency by a new invariant analysis respecting the symmetry of the effective field theory. A subtlety of the operator insertion, and the fast-slow mode separation within the effective field description is pointed out. 1. Introduction Since the dawn of mesoscopic physics, dynamical properties of small metallic grains have been attracting much attention both in experiments and in theories; they have been recognized as very useful physical realizations of the random matrix theory, because energy levels of such systems are known to exhibit strong repulsion as in random matrices. From a theoretical point of view, dynamical responses are much more complicated to investigate than energy level statistics. It is because the former requires an additional knowledge of electron wavefunctions or matrix elements in addition to energy spectra. In a pioneering paper by Gor’kov and Eliashberg (GE) [1], a phenomenological theory of dynamical responses was built based on the two statistical hypothesis: (i) independent fluctuations between matrix elements and energy levels (to single out the effect of the level repulsion), and (ii) the DOS correlator approximated by the Wigner-Dyson level correlator [2]. Although the original work was found to be insufficient in taking account of interaction effect [3, 4], the statistical approach has been widely accepted as a building block for subsequent studies [5, 6]. Although statistical hypothesis seems plausible, its microscopic justification is hard and often requires a sophisticated method. The parameter controlling the validity is the dimensionless conductance (for diffusive systems, where is the diffusion coefficient in a linear size and is the mean level spacing). To our knowledge, the only adequate tool to employ is the supermatrix nonlinear sigma (NL- ) approach [7], which proved the hypothesis (ii) in diffusive quantum dots with . Justifying the “decoupling” hypothesis (i) came rather late [8, 9]. However, such decoupling scheme may be oversimplified. Indeed, a new quantum effect sensitive to the time-reversal invariance (T-invariance) was observed in the limit of as a flux-dependent polarizability at [10, 11]. The effect has
Posttranslational Processing and Modification of Cathepsins and Cystatins
Nobuhiko Katunuma
Journal of Signal Transduction , 2010, DOI: 10.1155/2010/375345
Abstract: Cathepsins are an essential protease family in all living cells. The cathepsins play an essential roles such as protein catabolism and protein synthesis. To targeting to various organella and to regulate their activity, the post translational-processing and modification play an important role Cathepsins are translated in polysome as the pre-pro-mature forms. The pre-peptide is removed cotranslationally and then translocated to Golgi-apparatus and the pro-part is removed and the mature-part is glycosylated, and the mature-part is targeted into the lysosome mediated by mannose-6-phosphate signal and the mature-part is bound with their coenzymes. The degradation of the mature-part is started by the limited proteolysis of the ordered nicked bonds to make hydrophobic peptides. The peptides are incorporated into phagosome or proteasome after ubiquitinated and are degrade into amino-acids. Cystatins are endogenous inhibitors of cathepsins. Cystatin α which is only located in skin is phosphorylated at the near C-terminus by protein kinase-C, and the phosphorylate-cystatin α is incorporated into cornified envelope and conjugated with filaggrin-fiber by transglutaminase to form the linker-fiber of skin. The cystatin α is modified by glutathione or make their dimmer, and they are inactive. Those modifications are regulated by the redox-potential by the glutathione. 1. Introduction We will introduce recent advances on the study of post-translational processing, modification, and targeting of cathepsins and cystatins. Almost all the intracellular proteins are passed through principally similar processes from the synthesis to their degradation in general. Therefore, I would like to introduce the general fate of intracellular proteins, from the post-translational processing, modification, and targeting to the ordered particles. As Figure 1 shows, the intracellular proteins are synthesized as pre-promature complex in polysomes and prepart is removed cotranslationally, and then the promature parts are translocated into Golgi-apparatus, and then glycosylated by mannose-rich sugar. The glycosylated mature part is translocated into target organelles and the degradation was started by the splitting from the ordered nicked bonds to make hydrophobic peptides. These hydrophobic peptides are secreted to cytoplasm and are incorporated into the phagosomes or proteosomes after ubiquitination. Figure 1: Common process of post-translational proteins in general. Biological merit of post-translational processing [1] and modifications of proteins are Possible considerations. The
Nonperturbative Renormalization Group Function for Quantum Hall Plateau Transitions Imposed by Global Symmetries
Nobuhiko Taniguchi
Physics , 1998,
Abstract: As a unified theory of integer and fractional quantum Hall plateau transitions, a nonperturbative theory of the two-parameter scaling renormalization group function is presented. By imposing global symmetries known as ``the law of corresponding states'', we seek a possible form of renormalization group flows. Asking for consistency with the result from weak-localization perturbation theory, such restriction is so intense that we can analytically determine its concrete form. Accordingly, the critical exponent $\nu$ and the irrelevant scaling index $y$ are obtained analytically and turn out to be irrational. Their values ($\nu\approx 2.1$, $y\approx 0.3$) agree favorably well with experiments and numerics.
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