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Search Results: 1 - 10 of 626 matches for " Tomohisa Hattori "
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Rikkunshito and Ghrelin
Tomohisa Hattori
International Journal of Peptides , 2010, DOI: 10.1155/2010/283549
Abstract: Rikkunshito is a popular Japanese traditional medicine that is prescribed in Japan to treat various gastrointestinal tract disorders. In a double-blind controlled study, rikkunshito significantly ameliorated dysmotility-like dyspepsia and brought about a generalized improvement in upper gastric symptoms such as nausea and anorexia when compared with a control group. Several studies in rats have shown enhanced gastric emptying and a protective effect on gastric mucosa injury with rikkunshito administration. In addition, rikkunshito in combination with an anti-emetic drug is effective against anorexia and vomiting that occur as adverse reactions to chemotherapy in patients with advanced breast cancer. However, the mechanism by which rikkunshito alleviates gastrointestinal disorders induced by anticancer agents remains unclear. It has recently been shown that rikkunshito ameliorates cisplatin-induced anorexia by mediating an increase in the circulating ghrelin concentration. Moreover, Fujitsuka et al. found that decreased contractions of the antrum and duodenum in rats treated with a selective serotonin reuptake inhibitor were reversed by rikkunshito via enhancement of the circulating ghrelin concentration. These findings show that rikkunshito may be useful for treatment of anorexia and may provide a new strategy for improvement of upper gastrointestinal dysfunction. Rikkunshito is one of the few traditional Japanese medicines for which a double-blind study has been conducted. This trial was performed in patients with dysmotility-like dyspepsia [1, 2] based on a report that rikkunshito showed efficacy against non-ulcer dyspepsia, which is an old diagnostic classification. In a subsequent comparative clinical study, rikkunshito was found to be more effective than cisapride against undefined gastrointestinal complaints such as chronic gastritis [3]. Rikkunshito is prepared by compounding eight herbal medicines listed in the Japanese Pharmacopoeia: Atractylodis Lanceae Rhizoma, Ginseng Radix, Pinelliae Tuber, Hoelen, Zizyphi Fructus, Aurantii Nobilis Pericarpium, Glycyrrhizae Radix and Zingiberis Rhizoma. It has recently been shown that oral administration of rikkunshito stimulates secretion of the orexigenic peptide, ghrelin, from the stomach [4, 5]. In this section, the effects of rikkunshito are introduced, with main focus on the action of rikkunshito as an enhancer of ghrelin secretion. Anorexia is commonly seen in gastrointestinal diseases, although it is not a specific symptom. Anorexia is particularly common in chronic gastritis and gastric cancer but
Delivery of Plasmid DNA into Tumors by Intravenous Injection of PEGylated Cationic Lipoplexes into Tumor-Bearing Mice  [PDF]
Yoshiyuki Hattori
Pharmacology & Pharmacy (PP) , 2016, DOI: 10.4236/pp.2016.77034
Abstract: For systemic injection of cationic liposome/plasmid DNA (pDNA) complexes (cationic lipoplexes), polyethylene glycol (PEG)-modification (PEGylation) of lipoplexes can enhance their systemic stability. In this study, we examined whether intravenous injection of PEGylated cationic lipoplexes into tumor-bearing mice could deliver pDNA into tumor tissues and induce transgene expression. PEGylation of cationic liposomes could prevent their agglutination with erythrocytes. However, when PEGylated cationic lipoplexes were injected intravenously into tumor-bearing mice, they accumulated in tumor vascular vessels and did not exhibit transgene expression in tumors with both poor and well-developed vascularization. Furthermore, PEGylated cationic lipoplexes of CpG- free pDNA could not increase transgene expression in tumors after intravenous injection. These results suggested that PEGylation could not extravasate cationic lipoplexes from vascular vessels in tumors and abolished transgene expression although it enhanced the systemic stability of cationic lipoplexes by avoiding interactions with blood components such as erythrocytes. Successful delivery of pDNA to tumors by PEGylated cationic liposomes will require a rational strategy and the design of liposomal delivery systems to overcome the issue associated with the use of PEG.
Relationship between various supersymmetric lattice models
Tomohisa Takimi
Physics , 2007, DOI: 10.1088/1126-6708/2007/07/010
Abstract: We comment on the relationships between several supersymmetric lattice models; the ``orbifold lattice theory'' by Cohen-Kaplan-Katz-Unsal (CKKU), lattice regularization of the topological field theory by Sugino and the ``geometrical approach'' by Catterall. We point out that these three models have close relationships; the N =(2,2) model by Catterall [Catterall] and the two-dimensional N = (2,2) lattice theory being similar to Sugino's construction [Sugino] can be derived by appropriate truncation of fields in the two-dimensional N = (4,4) orbifold lattice theory by CKKU [Cohen et al]. Catterall's N = (2,2) description possesses extra degrees of freedom compared to the target N = (2,2) theory. If we remove those extra degrees of freedom in a way keeping supersymmetry on the lattice, Catterall's description reduces to a model of the Sugino type.
An anisotropic hybrid non-perturbative formulation for 4D N = 2 supersymmetric Yang-Mills theories
Tomohisa Takimi
Physics , 2012, DOI: 10.1007/JHEP08(2012)069
Abstract: We provide a simple non-perturbative formulation for non-commutative four-dimensional N = 2 supersymmetric Yang-Mills theories. The formulation is constructed by a combination of deconstruction (orbifold projection), momentum cut-off and matrix model techniques. We also propose a moduli fixing term that preserves lattice supersymmetry on the deconstruction formulation. Although the analogous formulation for four-dimensional N = 2 supersymmetric Yang-Mills theories is proposed also in Nucl.Phys.B857(2012), our action is simpler and better suited for computer simulations. Moreover, not only for the non-commutative theories, our formulation has a potential to be a non-perturbative tool also for the commutative four-dimensional N = 2 supersymmetric Yang-Mills theories.
Prescription for choosing an interpolating function
Tomohisa Takimi
Physics , 2014,
Abstract: Interpolating functional method is a powerful tool for studying the behavior of a quantity in the intermediate region of the parameter space of interest by using its perturbative expansions at both ends. Recently several interpolating functional methods have been proposed, in addition to the well-known Pade approximant, namely the "Fractional Power of Polynomial" (FPP) and the "Fractional Power of Rational functions" (FPR) methods. Since combinations of these methods also give interpolating functions, we may end up with multitudes of the possible approaches. So a criterion for choosing an appropriate interpolating function is very much needed. In this paper, we propose reference quantities which can be used for choosing a good interpolating function. In order to validate the prescription based on these quantities, we study the degree of correlation between "the reference quantities" and the "actual degree of deviation between the interpolating function and the true function" in examples where the true functions are known.
Fabrication of Sm-Based Perovskite-Type Oxide Thin-Films and Gas Sensing Properties to Acetylene  [PDF]
Tomohisa Tasaki, Satoko Takase, Youichi Shimizu
Journal of Sensor Technology (JST) , 2012, DOI: 10.4236/jst.2012.22011
Abstract: Sm-based perovskite-type oxide (SmMeO3: Me = Cr, Mn, Fe, Co) thin-films could be synthesized by a wet-chemical method using an acetylacetone—Poly(Vinyl Pyrrolidone) (PVP) polymeric precursor method at 750℃. The perovskite-type oxide thin-films were tried to apply an acetylene gas sensor based on AC impedance spectroscopy. Among the oxides tested, SmFeO3 thin-film sensor showed good sensor responses in which the AC impedance at 20 kHz was depending on acetylene gas concentration between 2 ppm and 80 ppm at 400℃.
Distinct iPS Cells Show Different Cardiac Differentiation Efficiency
Yohei Ohno,Shinsuke Yuasa,Toru Egashira,Tomohisa Seki,Hisayuki Hashimoto,Shugo Tohyama,Yuki Saito,Akira Kunitomi,Kenichiro Shimoji,Takeshi Onizuka,Toshimi Kageyama,Kojiro Yae,Tomofumi Tanaka,Ruri Kaneda,Fumiyuki Hattori,Mitsushige Murata,Kensuke Kimura,Keiichi Fukuda
Stem Cells International , 2013, DOI: 10.1155/2013/659739
Abstract: Patient-specific induced pluripotent stem (iPS) cells can be generated by introducing transcription factors that are highly expressed in embryonic stem (ES) cells into somatic cells. This opens up new possibilities for cell transplantation-based regenerative medicine by overcoming the ethical issues and immunological problems associated with ES cells. Despite the development of various methods for the generation of iPS cells that have resulted in increased efficiency, safety, and general versatility, it remains unknown which types of iPS cells are suitable for clinical use. Therefore, the aims of the present study were to assess (1) the differentiation potential, time course, and efficiency of different types of iPS cell lines to differentiate into cardiomyocytes in vitro and (2) the properties of the iPS cell-derived cardiomyocytes. We found that high-quality iPS cells exhibited better cardiomyocyte differentiation in terms of the time course and efficiency of differentiation than low-quality iPS cells, which hardly ever differentiated into cardiomyocytes. Because of the different properties of the various iPS cell lines such as cardiac differentiation efficiency and potential safety hazards, newly established iPS cell lines must be characterized prior to their use in cardiac regenerative medicine. 1. Introduction Embryonic stem (ES) cells are attractive candidates for use in cardiovascular stem cell-based therapy because mouse and human ES cells have been shown to have the capacity for unlimited proliferation and promising multipotency [1, 2]. Evidence also indicates that ES cells are one of the best candidates for use in cell-replacement therapy for cardiac diseases because of their ability to differentiate and proliferate, supplying a substantial number of mature human cardiac myocytes for transplantation into large, diseased human hearts [3–5]. Previous studies in animal models have shown that transplantation of ES cell-derived cardiac myocytes improves cardiac function and survival [6, 7]. However, the establishment and use of human ES cells remain contentious on ethical and legal grounds because of the origin of ES cells as well as concerns regarding immunological rejection or the need for immunosuppressant drugs after cell transplantation [8]. Mouse and human induced pluripotent stem (iPS) cells are artificially established pluripotent stem cells that resemble ES cells [9–16]. The iPS cells are similar to ES cells in terms of their morphology, proliferative ability, surface antigens, gene expression, epigenetic status of pluripotent stem
Equation of motion for incompressible mixed fluid driven by evaporation and its application to online rankings
Kumiko Hattori,Tetsuya Hattori
Physics , 2008,
Abstract: We give a unique classical solution to initial value problem for a system of partial differential equations for the densities of components of one dimensional incompressible fluid mixture driven by evaporation. Motivated by the known fact that the solution appears as an infinite particle limit of stochastic ranking processes, which is a simple stochastic model of time evolutions of e.g., Amazon Sales Ranks, we collected data from the web and performed statistical fits to our formula. The results suggest that the fluid equations and solutions may have an application in the analysis of online rankings.
Existence of an infinite particle limit of stochastic ranking process
Kumiko Hattori,Tetsuya Hattori
Mathematics , 2008, DOI: 10.1016/j.spa.2008.05.006
Abstract: We study a stochastic particle system which models the time evolution of the ranking of books by online bookstores (e.g., Amazon). In this system, particles are lined in a queue. Each particle jumps at random jump times to the top of the queue, and otherwise stays in the queue, being pushed toward the tail every time another particle jumps to the top. In an infinite particle limit, the random motion of each particle between its jumps converges to a deterministic trajectory. (This trajectory is actually observed in the ranking data on web sites.) We prove that the (random) empirical distribution of this particle system converges to a deterministic space-time dependent distribution. A core of the proof is the law of large numbers for {\it dependent} random variables.
Hydrodynamic limit of move-to-front rules and search cost probabilities
Kumiko Hattori,Tetsuya Hattori
Mathematics , 2009,
Abstract: We study a hydrodynamic limit approach to move-to-front rules, namely, a scaling limit as the number of items tends to infinity, of the joint distribution of jump rate and position of items. As an application of the limit formula, we present asymptotic formulas on search cost probability distributions, applicable for general jump rate distributions.
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