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Search Results: 1 - 10 of 4841 matches for " Takashi Imai "
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Comments on orientifold projection in the conifold and SO x USp duality cascade
Shin'ichi Imai,Takashi Yokono
Physics , 2001, DOI: 10.1103/PhysRevD.65.066007
Abstract: We study the O3-plane in the conifold. On the D3-brane world-volume we obtain SO x USp gauge theory that exhibits a duality cascade phenomenon. The orientifold projection is determined on the type IIB string side, and corresponds to that of O4-plane on the dual type IIA side. We show that SUGRA solutions of Klebanov-Tseytlin and Klebanov-Strassler survive under the projection. We also investigate the orientifold projection in the generalized conifolds, and verify desired features of the O4-projection in the type IIA picture.
Growth inhibition of a human colon carcinoma cell, COLO 201, by a natural product, Vitex agnus-castus fruits extract, in vivo and in vivo  [PDF]
Masahiko Imai, Bo Yuan, Hidetomo Kikuchi, Mai Saito, Kunio Ohyama, Chieko Hirobe, Takashi Oshima, Takahiro Hosoya, Hiroshi Morita, Hiroo Toyoda
Advances in Biological Chemistry (ABC) , 2012, DOI: 10.4236/abc.2012.21003
Abstract: An extract from ripe fruit of Vitex agnus-castus (Vitex) has been used to treat patients with various obstetric and gynecological disorders in Europe. We have demonstrated that Vitex showed cytocidal effects on various types of cancer cell lines including a human colon carcinoma cell line, COLO 201. In this study, we extended our previous study to investigate the detailed mechanisms underlying cytocidal effects of Vi- tex on COLO 201. Furthermore, a possible clinical application of Vitex was also explored in vivo using nude mice xenografted with the cells. Treatment with Vitex induced apoptosis in COLO 201 in a time-dependent manner, accompanying with activa-tion of caspase-9 and -3, but not caspase-8. An inhibitor for c-Jun NH2-terminal kinase (JNK), but not p38 mitogen-activated protein kinase (MAPK), significantly suppressed the apoptosis induction along with caspase-3 activation. Endoplasmic reticulum (ER) stress-related genes were also upregulated by Vitex treatment. Most importantly, the in vivo efficacy of Vitex evaluated by assessing the tumor growth revealed that the administration of Vitex significantly suppressed tumor growth in COLO 201 xenografted mice. Collectively, current results suggest that apoptosis induction by Vitex in COLO 201 is mediated through the activation of JNK and caspase-9, -3 resulted from ER stress. Based on the current clinical application of Vitex, these results thus provide a new insight into the clinical use of Vitex and leave open a possibility of a new regimen as an alternative medicine approach for such devastating colon cancer treatment.
Quantitative Microbiological Evaluation of Salmonella Typhimurium Shed in Diarrhea, Loose, and Normal Stools of Infected Pigs  [PDF]
Tsuyoshi Tanaka, Yasuo Imai, Naosuke Kumagae, Takashi Sasaki, Narutoshi Ochiai, Katsuyoshi Uruno, Haruki Kitazawa, Tadao Saito, Shizuo Sato
Open Journal of Veterinary Medicine (OJVM) , 2014, DOI: 10.4236/ojvm.2014.44007
Abstract:

Control of within-herd transmission of Salmonella is important for reducing the prevalence of this organism on pig farms and for preventing Salmonella-contamination of pork. At the farm level, understanding the within-herd transmission of Salmonella can lead to more effective control. Salmonella infection is dependent on the inoculation dose; hence, quantitative evaluation of Salmonella shed in feces would provide useful information for developing effective measures. In this study, to reproduce and evaluate the number of Salmonella shed in diarrhea, loose stools, and normal feces, weaned pigs were inoculated with 3.2 × 109, 3.2 × 107, and 3.2 × 105 cfu of Salmonella Typhimurium, respectively. The number of S. Typhimurium shed in the feces peaked within 1 week post-inoculation in every group and the most amount of diarrhea and loose stools were observed within 2 weeks post-inoculation. Diarrhea occurred 10 times (six pigs), and loose stools were observed 25 times (11 pigs). The average concentration of S. Typhimurium shed in diarrhea, loose stools, and normal feces was 1.0 × 108, 1.6 × 104, and 7.1 × 10

HPLC Retention time prediction for metabolome analysis
Takashi Hagiwara,Seiji Saito,Yoshifumi Ujiie,Kensaku Imai
Bioinformation , 2010,
Abstract: Liquid Chromatography Time-of-Flight Mass Spectrometry (LC-TOF-MS) is widely used for profiling metabolite compounds. LC-TOF-MS is a chemical analysis technique that combines the physical separation capabilities of high-pressure liquid chromatography (HPLC) with the mass analysis capabilities of Time-of-Flight Mass Spectrometry (TOF-MS) which utilizes the difference in the flight time of ions due to difference in the mass-to-charge ratio. Since metabolite compounds have various chemical characteristics, their precise identification is a crucial problem of metabolomics research. Contemporaneously analyzed reference standards are commonly required for mass spectral matching and retention time matching, but there are far fewer reference standards than there are compounds in the organism. We therefore developed a retention time prediction method for HPLC to improve the accuracy of identification of metabolite compounds. This method uses a combination of Support Vector Regression and Multiple Linear Regression adaptively to the measured retention time. We achieved a strong correlation (correlation coefficient = 0.974) between measured and predicted retention times for our experimental data. We also demonstrated a successful identification of an E. coli metabolite compound that cannot be identified by precise mass alone.
Superconducting properties of the ternary transition-metal silicide Zr2Ru3Si4
Soshi Ibuka,Motoharu Imai,Takashi Naka,Mitsuaki Nishio
Physics , 2013, DOI: 10.1088/0953-2048/27/2/025012
Abstract: Superconducting properties of the polycrystalline Zr2Ru3Si4 were investigated by the electrical resistivity, magnetization and specific heat. By these measurements, bulk superconductivity with transition temperature Tc = 5.5 K was confirmed. Moreover, Zr2Ru3Si4 was found to be a type-II and intermediate-coupling superconductor. Interestingly, the electronic specific heat shows a deviation from a one-gap s-wave model and Hc2(T) shows unusual positive curvature in the vicinity of Tc. The first principle's calculation shows the existence of plural anisotropic Fermi surfaces. These results suggest that Zr2Ru3Si4 is not an isotropic single-gap superconductor, but possibly a multi-gap or an anisotropic gap superconductor.
Oral administration of γ-aminobutyric acid affects heat production in a hot environment in resting humans
Taiki Miyazawa, Takashi Kawabata, Kazunobu Okazaki, Takashi Suzuki, Daiki Imai, Takeshi Hamamoto, Shinya Matsumura, Toshiaki Miyagawa
Journal of Physiological Anthropology , 2012, DOI: 10.1186/1880-6805-31-3
Abstract: Eight male participants drank a 200-ml sports drink with 1 g of GABA (trial G) or without GABA (trial C), then rested for 30 minutes in a sitting position in a hot environment (ambient air temperature 33°C, relative humidity 50%).We found that changes in esophageal temperature from before drinking the sports drink were lower in trial G than in trial C (-0.046 ± 0.079°C vs 0.001 ± 0.063°C; P < 0.05), with lower heat production calculated by oxygen consumption (41 ± 5 W/m2 vs 47 ± 8 W/m2; P < 0.05).In this study, we have demonstrated that a single oral administration of GABA induced a larger decrease in body core temperature compared to a control condition during rest in a hot environment and that this response was concomitant with a decrease in total heat production.γ-aminobutyric acid (GABA) is an amino acid that is widely distributed throughout the central nervous system (CNS) and is the most important depressive neurotransmitter [1]. GABA has important roles concerning temperature regulation in the hypothalamus. In experimental animals, it has been reported that central pharmacological stimulation of GABA in the dorsomedial hypothalamus (DMH) and the posterior hypothalamus (PH) inhibits heat production [2,3]. On the contrary, it has been reported that central pharmacological stimulation of GABA in the preoptic (PO) area and anterior hypothalamus (AH) increases heat production [4,5]. On the basis of these reports, it is assumed that central GABA stimulation to the hypothalamic region has some practical effect on temperature regulation.Few studies have examined the influence of systemic GABA stimulation on temperature regulation in either experimental animals or humans because the blood-brain barrier is impermeable to GABA [6] and it has long been thought that systemic administration of GABA cannot affect GABA's availability in the CNS [7,8]. However, it has been suggested that GABA could access certain areas of the brain that lack the blood-brain barrier [9-11], su
Trochanteric Fracture of a Congenital/Developmental Dislocation of the Hip in an Elderly Woman: A Case Report  [PDF]
Kazuhiro Imai
Open Journal of Orthopedics (OJO) , 2011, DOI: 10.4236/ojo.2011.11001
Abstract: An 87-year-old woman with a residual dislocated hip suffered a trochanteric fracture on the ipsilateral side. The fracture was treated by open reduction and internal fixation surgery with good results. To treat a proximal femoral fracture of the residual dislocated hip in an elderly patient, the patient’s overall status, pre-fracture ability, hip joint configuration, and fracture pattern should be considered.
In Vivo Investigation of Zr-Based Bulk Metallic Glasses Sub-Periosteally Implanted on the Bone Surface  [PDF]
Kazuhiro Imai
Journal of Materials Science and Chemical Engineering (MSCE) , 2016, DOI: 10.4236/msce.2016.41009
Abstract:

Bulk metallic glasses (BMG) show higher strength and lower Young’s modulus than SUS 316L stainless steel and Ti-6Al-4V alloys. This study aimed to investigate the reaction of Zr-based BMG sub-periosteally implanted on the surface of the rat femur, thereby evaluate the possibility of the BMG as biomaterials for osteosynthetic devices. Zr65Al7.5Ni10Cu17.5 BMG ribbons with 10 mm length, 2 mm width and 0.5 mm thickness were implanted sub-periosteally on the femur surface in three male Wistar rats for 6 weeks. Systemic effects were evaluated by measuring Cu and Ni levels in the blood, and local effects were evaluated by the histological observation of the surrounding soft tissues in contact with the BMG. The reaction of the surface of the BMG was examined with scanning electron microscopy. No increase of Cu and Ni levels in the blood was recognized. In the scanning electron microscopy observation, spherical deposits which were considered as sodium chloride crystals were observed. Neither breakage nor pitting corrosion was noted. BMG will be a promising metallic biomaterial for osteosynthetic device that must be removed.

Eco-Geographical Diversification of Bitter Taste Receptor Genes (TAS2Rs) among Subspecies of Chimpanzees (Pan troglodytes)
Takashi Hayakawa,Tohru Sugawara,Yasuhiro Go,Toshifumi Udono,Hirohisa Hirai,Hiroo Imai
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0043277
Abstract: Chimpanzees (Pan troglodytes) have region-specific difference in dietary repertoires from East to West across tropical Africa. Such differences may result from different genetic backgrounds in addition to cultural variations. We analyzed the sequences of all bitter taste receptor genes (cTAS2Rs) in a total of 59 chimpanzees, including 4 putative subspecies. We identified genetic variations including single-nucleotide variations (SNVs), insertions and deletions (indels), gene-conversion variations, and copy-number variations (CNVs) in cTAS2Rs. Approximately two-thirds of all cTAS2R haplotypes in the amino acid sequence were unique to each subspecies. We analyzed the evolutionary backgrounds of natural selection behind such diversification. Our previous study concluded that diversification of cTAS2Rs in western chimpanzees (P. t. verus) may have resulted from balancing selection. In contrast, the present study found that purifying selection dominates as the evolutionary form of diversification of the so-called human cluster of cTAS2Rs in eastern chimpanzees (P. t. schweinfurthii) and that the other cTAS2Rs were under no obvious selection as a whole. Such marked diversification of cTAS2Rs with different evolutionary backgrounds among subspecies of chimpanzees probably reflects their subspecies-specific dietary repertoires.
Progression of Oral Squamous Cell Carcinoma Accompanied with Reduced E-Cadherin Expression but Not Cadherin Switch
Takashi Hashimoto, Yuichi Soeno, Genta Maeda, Yuji Taya, Takaaki Aoba, Masanori Nasu, Shuichi Kawashiri, Kazushi Imai
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0047899
Abstract: The cadherin switch from E-cadherin to N-cadherin is considered as a hallmark of the epithelial-mesenchymal transition and progression of carcinomas. Although it enhances aggressive behaviors of adenocarcinoma cells, the significance and role of cadherin switch in squamous cell carcinomas (SCCs) are largely controversial. In the present study, we immunohistochemically examined expression of E-cadherin and N-cadherin in oral SCCs (n = 63) and its implications for the disease progression. The E-cadherin-positive carcinoma cells were rapidly decreased at the invasive front. The percentage of carcinoma cells stained E-cadherin at the cell membrane was reduced in parallel with tumor dedifferentiation (P<0.01) and enhanced invasion (P<0.01). In contrast, N-cadherin-positive cells were very limited and did not correlate with the clinicopathological parameters. Mouse tongue tumors xenotransplantated oral SCC cell lines expressing both cadherins in vitro reproduced the reduction of E-cadherin-positive carcinoma cells at the invasive front and the negligible expression of N-cadherin. These results demonstrate that the reduction of E-cadherin-mediated carcinoma cell-cell adhesion at the invasive front, but not the cadherin switch, is an important determinant for oral SCC progression, and suggest that the environments surrounding carcinoma cells largely affect the cadherin expression.
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