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Search Results: 1 - 10 of 2730 matches for " Takeo;Ito "
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Scattering of Noncommutative (n,1) Solitons
Takeo Araki,Katsushi Ito
Physics , 2001, DOI: 10.1016/S0370-2693(01)00897-8
Abstract: We study scattering of noncommutative solitons in 2+1 dimensional scalar field theory. In particular, we investigate a system of two solitons with level n and n' (the (n,n')-system) in the large noncommutativity limit. We show that the scattering of a general (n,n')-system occurs at right angles in the case of zero impact parameter. We also derive an exact Kahler potential and the metric of the moduli space of the (n,1)-system. We examine numerically the (n,1) scattering and find that the closest distance for a fixed scattering angle is well approximated by a function a+b*sqrt{n} where a and b are some numerical constants.
On the Moduli Space of Noncommutative Multi-solitons at Finite Theta
Takeo Araki,Katsushi Ito
Physics , 2002, DOI: 10.1016/S0370-2693(02)02903-9
Abstract: We study the finite theta correction to the metric of the moduli space of noncommutative multi-solitons in scalar field theory in (2+1) dimensions. By solving the equation of motion up to order O(theta^{-2}) explicitly, we show that the multi-soliton solution must have the same center for a generic potential term. We examine the condition that the multi-centered configurations are allowed. Under this condition, we calculate the finite theta correction to the metric of the moduli space of multi-solitons and argue the possibility of the non right-angle scattering of two solitons. We also obtain the potential between two solitons.
Long-Lived Unstable Superparticles at the LHC
Ishiwata, Koji;Ito, Takumi;Moroi, Takeo
High Energy Physics - Phenomenology , 2008, DOI: 10.1016/j.physletb.2008.09.024
Abstract: In various models of supersymmetry (SUSY), the lightest superparticle in the minimal SUSY standard model sector, which we call MSSM-LSP, becomes unstable. Then, we may observe the decay of the MSSM-LSP in the detector at the LHC experiment. We show that the discovery of such a decay process (and the determination of the lifetime of the MSSM-LSP) may be possible at the LHC even if the decay length of the MSSM-LSP is much longer than the size of the detector; sizable number of the MSSM-LSPs decay inside the detector if the lifetime is shorter than 0.01-1 millisec. We also discuss the implications of the study of the MSSM-LSP decay for several well-motivated SUSY models.
Radiolytic Reduction Characteristics of Artificial Oligodeoxynucleotides Possessing 2-Oxoalkyl Group or Disulfide Bonds
Kazuhito Tanabe,Takeo Ito,Sei-ichi Nishimoto
Journal of Nucleic Acids , 2011, DOI: 10.4061/2011/816207
Abstract: A number of advances have been made in the development of modified oligodeoxynucleotides (ODNs), and chemical or physical properties of which are controlled by external stimuli. These intelligent ODNs are promising for the next generation of gene diagnostics and therapy. This paper focuses on the molecular design of artificial ODNs that are activated by X-irradiation and their applications to regulation of hybridization properties, conformation change, radiation-activated DNAzyme, and decoy molecules. 1. Introduction Regulation of chemical or physical properties of oligodeoxynucleotides (ODNs) is important for the development of future gene diagnostics and therapy [1, 2]. Because the function of ODNs is based on their conformation and hybridization properties with their complementary DNA or RNA, various attempts have been made to manipulate these basic characteristics using chemical modification and external stimuli [3–11]. These include the binding of a metal ion to mismatched [3, 4] or modified nucleobases [5, 6], interaction of boron compounds with modified riboses [7, 8], and photochemical methods that use nitrobenzene [9, 10] or azobenzene [11] functionalities on ODNs. High-energy ionizing radiation is an attractive stimulus for controlling the activity of biomaterials, because the radiation reaction can be controlled spatially and temporally without any additives [12, 13]. In particular, X-ray has potential because it has high live-body permeability, and thus, has been extensively used for medical treatment and diagnosis. In this paper, we describe the current state of research on controlling the function of ODNs by X-irradiation. This paper includes our recent research on the development of artificial ODNs possessing a 2-oxoalkyl group [14] or disulfide bonds [15, 16], whose properties and conformation can be regulated by X-irradiation. We applied their characteristics to regulation of hybridization, radiation-activated DNAzyme, regulation of the polymerase reaction, and conformation change of ODNs and decoy molecules for inhibition of protein-DNA interactions. When diluted aqueous solutions are irradiated, practically all of the absorbed energy is deposited in water molecules, and the observed chemical changes are brought about indirectly by the molecular and, in particular, the radical products of water radiolysis. It is well known that ionization and excitation of water molecules by ionizing radiation occur and generate electronically excited states (H2O*), radical cations (H2O+?), and dry electrons ( ). The excited water molecules H2O*
Measles vaccine coverage and factors related to uncompleted vaccination among 18-month-old and 36-month-old children in Kyoto, Japan
Takayo Matsumura, Takeo Nakayama, Shigeru Okamoto, Hideko Ito
BMC Public Health , 2005, DOI: 10.1186/1471-2458-5-59
Abstract: Subjects were the parents whose children had undergone either an 18-month or a 36-month checkup publicly provided by Kyoto City during November 2001 to January 2002. An anonymous self-administered questionnaire survey was conducted.The coverage was 73.2% among the 18-month-old children (n = 2707) and 88.9% among the 36-month-old children (n = 2340), respectively. The following characteristics of mothers were related to uncompleted measles vaccination: aged below 30, working, concerned about the adverse events of the vaccine, and had insufficient knowledge. Similarly, the following characteristics among children were related to uncompleted measles vaccination: not the first-born child, interacting with other children in group settings. The coverage was the lowest among the children whose mothers were concerned about the adverse events of the vaccine without proper knowledge of measles and its vaccination.To increase vaccine coverage among children, parents' awareness about measles and vaccination against it should be promoted, especially for working mothers. Efforts to enhance access to vaccination services and to communicate with parents about changing vaccination schedules are necessary.Despite the existence of a safe, effective, and inexpensive vaccine, measles is still not being controlled in many parts of the world. The use of measles vaccine over the last 30 years has reduced global measles morbidity and mortality by 74 and 85%, respectively, compared with the prevaccine era. Regional elimination goals have been established in the Americas (by 2000), Europe (by 2007) and the Eastern Mediterranean (by 2010) [1].Vaccine coverage in excess of 95% interrupts endemic transmission of measles in many countries, but achievement of such coverage almost always requires great collaborative efforts. [2] The global strategy began in the 1990s and many countries implemented immunization and enhanced measles surveillance policies related to this during the late 1990's. Some (
Radiation- and Photo-induced Activation of 5-Fluorouracil Prodrugs as a Strategy for the Selective Treatment of Solid Tumors
Takeo Ito,Kazuhito Tanabe,Hisatsugu Yamada,Hiroshi Hatta
Molecules , 2008,
Abstract: 5-Fluorouracil (5-FU) is used widely as an anticancer drug to treat solid cancers, such as colon, breast, rectal, and pancreatic cancers, although its clinical application is limited because 5-FU has gastrointestinal and hematological toxicity. Many groups are searching for prodrugs with functions that are tumor selective in their delivery and can be activated to improve the clinical utility of 5-FU as an important cancer chemotherapeutic agent. UV and ionizing radiation can cause chemical reactions in a localized area of the body, and these have been applied in the development of site-specific drug activation and sensitization. In this review, we describe recent progress in the development of novel 5-FU prodrugs that are activated site specifically by UV light and ionizing radiation in the tumor microenvironment. We also discuss the chemical mechanisms underlying this activation.
Theory of the beta-type Organic Superconductivity under Uniaxial Compression
Takeo Suzuki,Seiichiro Onari,Hiroshi Ito,Yukio Tanaka
Physics , 2010, DOI: 10.1143/JPSJ.80.094704
Abstract: We study theoretically the shift of the superconducting transition temperature (Tc) under uniaxial compression in beta-type organic superconductors, beta-(BEDT-TTF)2I3 and beta-(BDA-TTP)2X[X=SbF6,AsF6], in order to clarify the electron correlation, the spin frustration and the effect of dimerization. The transfer integrals are calculated by the extended Huckel method assuming the uniaxial strain and the superconducting state mediated by the spin fluctuation is solved using Eliashberg's equation with the fluctuation-exchange approximation. The calculation is carried out on both the dimerized (one-band) and nondimerized (two-band) Hubbard models. We have found that (i) the behavior of Tc in beta-(BEDT-TTF)2I3 with a stronger dimerization is well reproduced by the dimer model, while that in weakly dimerized beta-BDA-TTP salts is rather well reproduced by the two-band model, and (ii) the competition between the spin frustration and the effect induced by the fluctuation is important in these materials, which causes nonmonotonic shift of Tc against uniaxial compression.
Radiation- and Photo-induced Activation of 5-Fluorouracil Prodrugs as a Strategy for the Selective Treatment of Solid Tumors
Takeo Ito,Kazuhito Tanabe,Hisatsugu Yamada,Hiroshi Hatta,Sei-ichi Nishimoto
Molecules , 2008, DOI: 10.3390/molecules13102370
Abstract: 5-Fluorouracil (5-FU) is used widely as an anticancer drug to treat solid cancers, such as colon, breast, rectal, and pancreatic cancers, although its clinical application is limited because 5-FU has gastrointestinal and hematological toxicity. Many groups are searching for prodrugs with functions that are tumor selective in their delivery and can be activated to improve the clinical utility of 5-FU as an important cancer chemotherapeutic agent. UV and ionizing radiation can cause chemical reactions in a localized area of the body, and these have been applied in the development of site-specific drug activation and sensitization. In this review, we describe recent progress in the development of novel 5-FU prodrugs that are activated site specifically by UV light and ionizing radiation in the tumor microenvironment. We also discuss the chemical mechanisms underlying this activation.
Epidemiology of vampire bat-transmitted rabies virus in Goiás, central Brazil: re-evaluation based on G-L intergenic region
Shinji Hirano, Takuya Itou, Adolorata AB Carvalho, Fumio H Ito, Takeo Sakai
BMC Research Notes , 2010, DOI: 10.1186/1756-0500-3-288
Abstract: The vampire bat-transmitted rabies virus isolates divided into 8 phylogenetic lineages in the previous nucleoprotein gene analysis were divided into 10 phylogenetic lineages with significant bootstrap values. The distributions of most variants were reconfirmed to be delimited by mountain chains. Furthermore, variants in undulating areas have narrow distributions and are apparently separated by mountain ridges.This study demonstrates that the 619-nt sequence including G-L intergenic region is more useful for a state-level phylogenetic analysis of rabies virus than the partial nucleoprotein gene, and simultaneously that the distribution of vampire bat-transmitted RABV variants tends to be separated not only by mountain chains but also by mountain ridges, thus suggesting that the diversity of vampire bat-transmitted RABV variants was delimited by geographical undulations.Rabies is a zoonosis that kills infected mammals, including humans, and is mainly transmitted by carnivores. In the Americas, chiropterans (insectivorous, frugivorous and hematophagous bat) are another reservoir of this disease. Although dog-transmitted rabies in central Brazil has been reduced by aggressive vaccination programs [1], chiroptera (particularly the common vampire bat, Desmodus rotundas)-transmitted rabies remains endemic in this region, and harms both the livestock industry and the public health sector [2,3].To date, vampire bat-transmitted rabies in livestock has been controlled by reducing the population of vampire bats and by vaccinating livestock [3,4]. However, the depopulation of vampire bats has limitations and the effects are temporary, while vaccination of livestock is only carried out for some animals and is ineffective in decreasing rabies levels in vampire bats.For the sustainable and effective control of vampire bat rabies, further knowledge of epidemiological features, such as vampire bat ecology and the dynamics of vampire bat-transmitted rabies, is necessary. Molecular epi
Molecular epidemiology of livestock rabies viruses isolated in the northeastern Brazilian states of Paraíba and Pernambuco from 2003 - 2009
Nobuyuki Mochizuki, Hiroyuki Kawasaki, Maria LCR Silva, José AB Afonso, Takuya Itou, Fumio H Ito, Takeo Sakai
BMC Research Notes , 2012, DOI: 10.1186/1756-0500-5-32
Abstract: Phylogenetic analysis based on 890 nt of the nucleoprotein (N) gene revealed that the 52 livestock-derived RABV isolates characterized here belonged to a single lineage. These isolates clustered with a vampire bat-related RABV lineage previously identified in other states in Brazil; within PB and PE, this lineage was divided between the previously characterized main lineage and a novel sub-lineage.The occurrences of livestock rabies in PB and PE originated from vampire bat RABVs, and the causative RABV lineage has been circulating in this area of northeastern Brazil for at least 7 years. This distribution pattern may correlate to that of a vampire bat population isolated by geographic barriers.Rabies is a fatal infectious disease that causes encephalomyelitis. In Brazil, various rabies viruses (RABVs) have been isolated from numerous animal species, including dogs, foxes, cats, and cattle, as well as from hematophagous, insectivorous, and frugivorous bats. Vampire bats, particularly Desmodus rotundus, are an important rabies vector in Latin America. Transmission from vampire bats to humans has been reported, primarily in the Amazon regions of Brazil and Peru, and a large number of cases of cattle rabies transmitted by vampire bats also have been reported in Brazil [1]. Since the introduction of a regional elimination program, the incidence of human and canine rabies in Latin America has fallen by 90% over the past 20 years. However, northeastern Brazil remains a "hotspot" for human rabies because of circulation of the virus among the dog population [2]. Carnieli Jr. et al. reported the molecular characterization and epidemiology of RABVs isolated from canids in northeastern Brazil [3-5], and Shoji et al. reported the genetic and phylogenetic characterization of RABVs isolated from wild fox, insectivorous bats, and livestock in Paraíba (PB) [6]. In Olinda, a city in Pernambuco (PE), 7,062 patients underwent prophylactic antirabies treatment between 2002 and 2006 [7].
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