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Search Results: 1 - 10 of 5211 matches for " Akira Kobayashi "
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Denaturation of DNA in Ternary Mixed Solution of Water/Hydrophilic/Hydrophobic Organic Solvent  [PDF]
Yuki Ito, Kazuhiko Tsukagoshi, Akira Kobayashi
Journal of Analytical Sciences, Methods and Instrumentation (JASMI) , 2017, DOI: 10.4236/jasmi.2017.72004
Abstract: Denaturation was examined for the first time in a ternary mixed solution of water/hydrophilic/ hydrophobic organic solvent using λ-DNA and a plasmid as models. The absorbance of λ-DNA and the plasmid at 260 nm gradually increased for several days up to 1.68 and 1.38 times the initial values, respectively, in a water/acetonitrile/ethyl acetate (15:3:2, volume ratio) mixed solution, whereas there was little change in a water/acetonitrile (15:3, volume ratio) mixed solution. The plasmid treated with the ternary mixed solution was also examined with agarose gel electrophoresis. These experimental data indicated that λ-DNA changed from a double helix structure to a single helix structure and that the plasmid partially transformed to generate a denaturation bubble in the structure. The new idea of using the ternary mixed solution first enabled the interaction of the hydrophobic organic solvent (e.g., ethyl acetate) molecule with the double helical structure of DNA, leading to specific slow-proceeding denaturation.
Advances in therapeutics for liver metastasis from colorectal cancer
Akira Kobayashi,Shinichi Miyagawa
World Journal of Gastrointestinal Oncology , 2010,
Abstract: The evolution of chemotherapeutic regimens that include targeted molecular agents has resulted in a breakthrough in the management of advanced colorectal liver metastasis (CLM), improving the progression-free survival after liver resection, and rendering initially unresectable liver tumors resectable, with reported resection rates ranging from 13% to 51%. In addition, the criteria used for selecting patients for hepatectomy have been expanding because of advances in surgical techniques and improvements in chemotherapy. However, the increasing use of chemotherapy has raised concern about potential hepatotoxicities such as steatosis, chemotherapy-associated steatohepatitis, and sinusoidal obstruction syndrome, and their deleterious effects on postoperative outcome. The present review focuses on the advantages and disadvantages of chemotherapy, strategies for the prevention and diagnosis of chemotherapy-associated liver injury, and the adoption of more aggressive surgical approaches, which have changed the traditional paradigm for CLM.
Gender-typical olfactory regulation of sexual behavior in goldfish
Akira Nagaoka,Makito Kobayashi
Frontiers in Neuroscience , 2014, DOI: 10.3389/fnins.2014.00091
Abstract: It is known that olfaction is essential for the occurrence of sexual behavior in male goldfish. Sex pheromones from ovulatory females elicit male sexual behavior, chasing, and sperm releasing act. In female goldfish, ovarian prostaglandin F2α (PGF) elicits female sexual behavior, egg releasing act. It has been considered that olfaction does not affect sexual behavior in female goldfish. In the present study, we re-examined the involvement of olfaction in sexual behavior of female goldfish. Olfaction was blocked in male and female goldfish by two methods: nasal occlusion (NO) which blocks the reception of olfactants, and olfactory tract section (OTX) which blocks transmission of olfactory information from the olfactory bulb to the telencephalon. Sexual behavior of goldfish was induced by administration of PGF to females, an established method for inducing goldfish sexual behavior in both sexes. Sexual behavior in males was suppressed by NO and OTX as previously reported because of lack of pheromone stimulation. In females, NO suppressed sexual behavior but OTX did not affect the occurrence of sexual behavior. Females treated with both NO and OTX performed sexual behavior normally. These results indicate that olfaction is essential in female goldfish to perform sexual behavior as in males but in a different manner. The lack of olfaction in males causes lack of pheromonal stimulation, resulting in no behavior elicited. Whereas the results of female experiments suggest that lack of olfaction in females causes strong inhibition of sexual behavior mediated by the olfactory pathway. Olfactory tract section is considered to block the pathway and remove this inhibition, resulting in the resumption of the behavior. By subtract sectioning of the olfactory tract, it was found that this inhibition was mediated by the medial olfactory tracts, not the lateral olfactory tracts. Thus, it is concluded that goldfish has gender-typical olfactory regulation for sexual behavior.
Superradiant scattering of electromagnetic waves emitted from disk around Kerr black holes
Taichi Kobayashi,Akira Tomimatsu
Physics , 2010, DOI: 10.1103/PhysRevD.82.084026
Abstract: We study electromagnetic perturbations around a Kerr black hole surrounded by a thin disk on the equatorial plane. Our main purpose is to reveal the black hole superradiance of electromagnetic waves emitted from the disk surface. The outgoing Kerr-Schild field is used to describe the disk emission, and the superradiant scattering is represented by a vacuum wave field which is added to satisfy the ingoing condition on the horizon. The formula to calculate the energy flux on the disk surface is presented, and the energy transport in the disk-black hole system is investigated. Within the low-frequency approximation we find that the energy extracted from the rotating black hole is mainly transported back to the disk, and the energy spectrum of electromagnetic waves observed at infinity is also discussed.
Electrochemical Characterization of Plasma Sprayed Alumina Coatings  [PDF]
Magdi. F. MORKS, Ivan COLE, Penny Corrigan, Akira KOBAYASHI
Journal of Surface Engineered Materials and Advanced Technology (JSEMAT) , 2011, DOI: 10.4236/jsemat.2011.13016
Abstract: Open circuit potential (OCP), potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) were employed to characterize the corrosion behavior of plasma-sprayed alumina-coated mild steel in 3.5 wt% NaCl solu-tion. Alumina-coated steel showed higher OCP and lower corrosion current (icorr.) compared with the steel substrate. However, localized corrosion probably occurs at the coat/steel interface when immersed in the corrosive media. The reason for that is the penetration of corrosive solution into the steel surface through the pores of accumulated alumina layers. The corrosion products (mainly iron oxides) accumulate inside the pores and on the coating surface. The presence of iron oxide slightly improved the corrosion resistance.
Amino acid profiles in relation to chronic periodontitis and rheumatoid arthritis  [PDF]
Tetsuo Kobayashi, Moe Okada, Satoshi Ito, Daisuke Kobayashi, Atsuko Shinhara, Takahiko Muramatsu, Tsuyoshi Kobayashi, Ichiei Narita, Kiyoshi Nakazono, Akira Murasawa, Hiromasa Yoshie
Open Journal of Stomatology (OJST) , 2014, DOI: 10.4236/ojst.2014.42009
Abstract: Chronic periodontitis (CP) and rheumatoid arthritis (RA) are chronic inflammatory conditions, and share many pathologic features. Plasma amino acid profiles have been shown to be associated with RA, but their relevance to CP remains unclear. The aim of the present study is to evaluate amino acid profiles in relation to CP and RA. The study participants consisted of 62 patients with RA (RA group), 30 patients with CP (CP group) and 29 healthy controls (H group) in age-, gender-, smoking status-balanced condition. Clinical periodontal and rheumatologic parameter values and plasma levels of 21 amino acids, C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) were determined. Multiple comparison analyses revealed that the RA group exhibited similar periodontal conditions but significantly higher levels of CRP, IL-6, and TNF-α than the CP group (P < 0.01). A total of four amino acids (glycine, histidine, ornithine, and alpha-aminobutyric acid) were significantly different in the concentrations among the three groups (P < 0.01). The RA group displayed significantly lower levels of glycine and histidine and significantly higher ornithine level than the CP and H groups (P < 0.01). The CP group showed significantly higher alpha-aminobutyric acid level than the RA and H groups (P < 0.01). Of these four amino acids, a significantly positive correlation was found between ornithine level and % of sites with bleeding on probing (P = 0.006) in the RA group. These results suggest a possibility that profiles of four amino acids may play a role in the pathogenesis of CP and RA.
Development of a Molecular Marker to Identify a Candidate Line of Turmeric (Curcuma longa L.) with a High Curcumin Content  [PDF]
Hiroshi Hayakawa, Tetsuya Kobayashi, Yukio Minaniya, Katsura Ito, Akira Miyazaki, Tatsuya Fukuda, Yoshinori Yamamoto
American Journal of Plant Sciences (AJPS) , 2011, DOI: 10.4236/ajps.2011.21002
Abstract: Dried and fresh rhizomes of the spice turmeric (Curcuma longa L.) are well known in traditional medicine, and curcu- min is widely used in various geographic regions. Although there are differences in the amount of curcumin within this species, identification of the candidate line by rhizome is difficult because of the relative simplicity of its morphological characteristics. To accurately identify lines of C. longa with a high content of curcumin, we analysed several sequences of chloroplast DNA. First, to determine the appropriate outgroup taxa in which to conduct infras-pecific analyses of C. longa, we reconstructed the molecular phylogenetic tree of C. longa and its allied species. The results showed that C. aromatica and C. zedoaria are closely related to C. longa. Next, to develop a molecular marker for identifying lines of C. longa with a high content of curcumin, a network analysis using chloroplast microsatellite regions was performed. Results showed that a unique haplotype within C. longa corresponds to the high curcumin content line. Therefore, the chloroplast microsatellite regions used for the analysis allowed us to determine the lines of this species with high cur- cumin content.
Gynecological tumors in patients with Peutz-Jeghers syndrome (PJS)  [PDF]
Arisa Ueki, Iori Kisu, Kouji Banno, Megumi Yanokura, Kennta Masuda, Yusuke Kobayashi, Akira Hirasawa, Daisuke Aoki
Open Journal of Genetics (OJGen) , 2011, DOI: 10.4236/ojgen.2011.13012
Abstract: Peutz-Jeghers syndrome (PJS) is an autosomal dominant disorder characterized by the development of hamartomatous polyposis in the gastrointestinal tract and melanin-pigmented macules on the skin mucosa. The responsible gene is a tumor suppressor, STK11/LKB1, on chromosome 19p13.3. PJS complicates with benign and malignant tumors in various organs. In gynecology, there has been a particular focus on complications of PJS with sex cord tumor with annular tubules (SCTAT) and minimal deviation adenocarcinoma (MDA), which are rare diseases. Approximately 36% of patients with SCTAT are complicated with PJS and these patients are characterized by multifocal, bilateral, small and benign lesions that develop into tumors with mucinous to serous ratios of 8:1. In addition, 10% of cases of MDA are complicated with PJS and mutation of STK11, the gene responsible for PJS, has a major effect on onset and prognosis. The disease concept of lobular endocervical glandular hyper-plasia (LEGH) has recently been proposed and LEGH is thought to be a potential premalignant lesion of MDA, however, the relationship between PJS and LEGH remains unclear. Several case reports of PJS patients complicated with gynecological tumors have been published and further studies are needed to determine the underlying causes
Relationships between Stages and Processes of Change for Effective Stress Management in Japanese College Students  [PDF]
Satoshi Horiuchi, Akira Tsuda, Janice M. Prochaska, Hisanori Kobayashi, Kengo Mihara
Psychology (PSYCH) , 2012, DOI: 10.4236/psych.2012.36070
Abstract: With a primary prevention focus, it would be important to help populations engage in stress management. The Transtheoretical Model of Behavior Change is one of potentially useful models to formulate interventions. The model describes behavior change as progression through five stages: precontemplation (not ready), contemplation (getting ready), preparation (ready), action, and maintenance. Processes of change (strategies and techniques to enhance the progression) facilitate stage transition. Their use is hypothesized to depend on stage of change. The processes tend to be used the least at the precontemplation stage. Use of experiential processes (affective and/or cognitive strategies such as seeking information) increase over time and tend to peak at the contemplation or preparation stage and then decease. In contrast, behavioral processes (behavioral strategies such as seeking social support) tend to be used most at the action and/or maintenance stage. This study examined relationships between stages and processes of change for effective stress management. Effective stress management is defined as any form of healthy activity such as exercising, meditating, relaxing, and seeking social support, which is practiced for at least 20 minutes. Four hundred and five Japanese college students participated in this study. A paper-pencil survey was conducted at colleges in Japan. The process use was least in precontemplation. Experiential processes peaked in preparation. Except for one experiential process, no significant difference was found between preparation and maintenance. Behavioral processes peaked in preparation, action, or maintenance. Most of these inter-stage differences of processes are in line with the prediction from the model. This study represented an initial but important test of validity of applying processes of change to stress management. The results partially supported its application.
Vegetative Compatibility Groups within Fusarium oxysporum f. sp. cepae in Hokkaido-Japan
Microbiology Indonesia , 2008,
Abstract: In Hokkaido, Fusarium basal rot, caused by Fusarium oxysporum f. sp. cepae is one of the important constrains since 1973 which contributes to a significant loss in onion production, either in the fields or during storage. Development of resistant cultivars is suggested as one of the effective control measures against the disease, however, this should be accompanied with the better understanding of the pathogen’s population dynamics. This study was performed to investigate the population structure of F. oxysporum f. sp. cepae based on vegetative compatibility groupings (VCGs). Vegetative compatibility groups of F.oxysporum f. sp. cepae were characterized using nitrate non-utilizing (nit) mutants. Four VCGs and 2 single self-compatible (SSC) isolates were identified among 48 isolates, designated as VCG 0420 (33 isolates), 0421 (9 isolates), 0422 (2 isolates), 0423 (2 isolates), and 042-(2 isolates). VCG 0420, to which 4 ATCC isolates out of 6 belonged, was the predominant group within the growing region encompassing Hokkaido Japan. VCGs 0421 and artificial VCG 042- were found less frequently. Four isolates from Welsh onion were not compatible with any recovered VCGs and were assigned to 2 distinct VCGs (VCG 0422 and 0423).
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