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Search Results: 1 - 10 of 4645 matches for " Takashi Higuchi "
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Measuring the mass distribution of voids with stacked weak lensing
Yuichi Higuchi,Masamune Oguri,Takashi Hamana
Physics , 2012, DOI: 10.1093/mnras/stt521
Abstract: We study the prospects for measuring the dark matter distribution of voids with stacked weak lensing. We select voids from a large set of $N$-body simulations, and explore their lensing signals with the full ray-tracing simulations including the effect of the large-scale structure along the line-of-sight. The lensing signals are compared with simple void model predictions to infer the three-dimensional mass distribution of voids. We show that the stacked weak lensing signals are detected at significant level (S/N$\geq5$) for a 5000 degree$^2$ survey area, for a wide range of void radii up to $\sim50$ Mpc. The error from the galaxy shape noise little affects lensing signals at large scale. It is also found that dense ridges around voids have a great impact on the weak lensing signals, suggesting that proper modeling of the void density profile including surrounding ridges is essential for extracting the average total underdens mass of voids.
Alcohol drinking rates of male between 7th and 11th graders in Japan decreased gradually based on nationwide repeated cross-sectional surveys from 1996 to 2008  [PDF]
Hideyuki Kanda, Yoneatsu Osaki, Yoshitaka Kaneita, Osamu Itani, Maki Ikeda, Takashi Ohida, Susumu Higuchi
Health (Health) , 2013, DOI: 10.4236/health.2013.56A3003
Abstract: Early drinking is considered to result in making tolerant of alcohol consumption and a higher prevalence of alcohol related disorders in the later. We focused generational impacts on drinking rate among high school students based on multiple nationwide data. The surveys were nationwide, cross-sectional random sampling surveys given every 4 years from the Japanese Youth Tobacco and Alcohol Surveys, 1996 to 2008. Participants were male 53,925 high school students from 7th grade to 11th grade. We divided to the three follow-up groups every 4 years from 1996 to 2004 for male junior high school students in 7th grades and the end periods were 4 years later in 11th grades. Outcome measures in this study were life time drinking, current drinking within 30 days and weekly drinking. All drinking rates decreased each at 7th and at 11th grade. The increments in these drinking rates from 7th grade to 11th grade in males decreased gradually in recent follow-up groups. Generational impacts should be considered by using follow-up groups to study drinking behaviors among students.
Influence of Parasitic Capacitance on Output Voltage for Series-Connected Thin-Film Piezoelectric Devices
Kensuke Kanda,Takashi Saito,Yuki Iga,Kohei Higuchi,Kazusuke Maenaka
Sensors , 2012, DOI: 10.3390/s121216673
Abstract: Series-connected thin film piezoelectric elements can generate large output voltages. The output voltage ideally is proportional to the number of connections. However, parasitic capacitances formed by the insulation layers and derived from peripheral circuitry degrade the output voltage. Conventional circuit models are not suitable for predicting the influence of the parasitic capacitance. Therefore we proposed the simplest model of piezoelectric elements to perform simulation program with integrated circuit emphasis (SPICE) circuit simulations). The effects of the parasitic capacitances on the thin-film Pb(Zr, Ti)O3, (PZT) elements connected in series on a SiO2 insulator are demonstrated. The results reveal the negative effect on the output voltage caused by the parasitic capacitances of the insulation layers. The design guidelines for the devices using series-connected piezoelectric elements are explained.
Improved techniques for double-balloon-enteroscopy-assisted endoscopic retrograde cholangiopancreatography
Takashi Osoegawa,Yasuaki Motomura,Kazuya Akahoshi,Naomi Higuchi
World Journal of Gastroenterology , 2012, DOI: 10.3748/wjg.v18.i46.6843
Abstract: AIM: To investigate the clinical outcome of double balloon enteroscopy (DBE)-assisted endoscopic retrograde cholangiopancreatography (DB-ERCP) in patients with altered gastrointestinal anatomy. METHODS: Between September 2006 and April 2011, 47 procedures of DB-ERCP were performed in 28 patients with a Roux-en-Y total gastrectomy (n = 11), Billroth II gastrectomy (n = 15), or Roux-en-Y anastomosis with hepaticojejunostomy (n = 2). DB-ERCP was performed using a short-type DBE combined with several technical innovations such as using an endoscope attachment, marking by submucosal tattooing, selectively applying contrast medium, and CO2 insufflations. RESULTS: The papilla of Vater or hepaticojejunostomy site was reached in its entirety with a 96% success rate (45/47 procedures). There were no significant differences in the success rate of reaching the blind end with a DBE among Roux-en-Y total gastrectomy (96%), Billroth II reconstruction (94%), or pancreatoduodenectomy (100%), respectively (P = 0.91). The total successful rate of cannulation and contrast enhancement of the target bile duct in patients whom the blind end was reached with a DBE was 40/45 procedures (89%). Again, there were no significant differences in the success rate of cannulation and contrast enhancement of the target bile duct with a DBE among Roux-en-Y total gastrectomy (88 %), Billroth II reconstruction (89%), or pancreatoduodenectomy (100%), respectively (P = 0.67). Treatment was achieved in all 40 procedures (100%) in patients whom the contrast enhancement of the bile duct was successful. Common endoscopic treatments were endoscopic biliary drainage (24 procedures) and extraction of stones (14 procedures). Biliary drainage was done by placement of plastic stents. Stones extraction was done by lithotomy with the mechanical lithotripter followed by extraction with a basket or by the balloon pull-through method. Endoscopic sphincterotomy was performed in 14 procedures with a needle precutting knife using a guidewire. The mean total duration of the procedure was 93.6 ± 6.8 min and the mean time required to reach the papilla was 30.5 ± 3.7 min. The mean time required to reach the papilla tended to be shorter in Billroth II reconstruction (20.9 ± 5.8 min) than that in Roux-en-Y total gastrectomy (37.1 ± 4.9 min) but there was no significant difference (P = 0.09). A major complication occurred in one patient (3.5%); perforation of the long limb in a patient with Billroth II anastomosis. CONCLUSION: Short-type DBE combined with several technical innovations enabled us to perform ERCP in mo
Observation of Environmental Stress Cracking in Polymethylmethacrylate by Using the Chemiluminescence Method  [PDF]
Yuji Higuchi
Materials Sciences and Applications (MSA) , 2015, DOI: 10.4236/msa.2015.611107
Abstract: Polymethylmethacrylate (PMMA) is highly regarded for its transparency, and is used in such products as cameras and Video Tape Recorders as plastic lenses to take advantage of its excellent optical properties. Also, it is used in numerous other industrial fields like automobile lamp lenses, billboards, and lighting equipment. The phenomenon of environmental stress cracking is known to occur in PMMA due to ethanol, and there are cases when this may become a factor which causes damage of molded products. In the present paper, upon close observation by using the method of chemiluminescence in order to elucidate the mechanism by which this environmental stress cracking occurs, we report that we are able to capture the formation of a radical at the moment of cracking.
PPAR Activation Protects against Anti-Thy1 Nephritis by Suppressing Glomerular NF- B Signaling
Koji Hashimoto,Yuji Kamijo,Takero Nakajima,Makoto Harada,Makoto Higuchi,Takashi Ehara,Hidekazu Shigematsu,Toshifumi Aoyama
PPAR Research , 2012, DOI: 10.1155/2012/976089
Abstract: The vast increase of chronic kidney disease (CKD) has attracted considerable attention worldwide, and the development of a novel therapeutic option against a representative kidney disease that leads to CKD, mesangial proliferative glomerulonephritis (MsPGN) would be significant. Peroxisome proliferator-activated receptor α (PPARα), a member of the steroid/nuclear receptor superfamily, is known to perform various physiological functions. Recently, we reported that PPARα in activated mesangial cells exerted anti-inflammatory effects and that the deficiency of PPARα resulted in high susceptibility to glomerulonephritis. To investigate whether PPARα activation improves the disease activity of MsPGN, we examined the protective effects of a PPARα agonist, clofibrate, in a well-established model of human MsPGN, anti-Thy1 nephritis, for the first time. This study demonstrated that pretreatment with clofibrate (via a 0.02% or 0.1% clofibrate-containing diet) continuously activated the glomerular PPARα, which outweighed the PPARα deterioration associated with the nephritic process. The PPARα activation appeared to suppress the NF-κB signaling pathway in glomeruli by the induction of IκBα, resulting in the reduction of proteinuria and the amelioration of the active inflammatory pathologic glomerular changes. These findings suggest the antinephritic potential of PPARα-related medicines against MsPGN. PPARα-related medicines might be useful as a treatment option for CKD. 1. Introduction The vast increase in chronic kidney disease (CKD) has attracted considerable attention worldwide, since CKD is one of the most important risk factors for cardiovascular events, the induction of kidney replacement therapies, and death [1]. Among many types of primary kidney disease, mesangial proliferative glomerulonephritis (MsPGN) including IgA nephropathy is a representative proteinuric kidney disease that leads to CKD [2, 3]. Various medications such as angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, fish oil, statins, hydroxymethylglutaryl-CoA reductase inhibitors, immunosuppressive therapy, antiplatelets, and anticoagulants have been proposed; however, it remains difficult to control the nephritic activity associated with severe inflammatory pathologic glomerular changes [4]. It is known that the marked activation of nuclear factor kappa B (NF-κB) was detected in various kidney cells from MsPGN patients, including mesangial cells, glomerular endothelial and epithelial cells, tubular epithelial cells, and infiltrating cells and that the NF-κB
Dietary Deficiency of Essential Amino Acids Rapidly Induces Cessation of the Rat Estrous Cycle
Kazumi Narita, Kenji Nagao, Makoto Bannai, Toru Ichimaru, Sayako Nakano, Takuya Murata, Takashi Higuchi, Michio Takahashi
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0028136
Abstract: Reproductive functions are regulated by the sophisticated coordination between the neuronal and endocrine systems and are sustained by a proper nutritional environment. Female reproductive function is vulnerable to effects from dietary restrictions, suggesting a transient adaptation that prioritizes individual survival over reproduction until a possible future opportunity for satiation. This adaptation could also partially explain the existence of amenorrhea in women with anorexia nervosa. Because amino acid nutritional conditions other than caloric restriction uniquely alters amino acid metabolism and affect the hormonal levels of organisms, we hypothesized that the supply of essential amino acids in the diet plays a pivotal role in the maintenance of the female reproductive system. To test this hypothesis, we examined ovulatory cyclicity in female rats under diets that were deficient in threonine, lysine, tryptophan, methionine or valine. Ovulatory cyclicity was monitored by daily cytological evaluations of vaginal smears. After continuous feeding of the deficient diet, a persistent diestrus or anovulatory state was induced most quickly by the valine-deficient diet and most slowly by the lysine-deficient diet. A decline in the systemic insulin-like growth factor 1 level was associated with a dietary amino acid deficiency. Furthermore, a paired group of rats that were fed an isocaloric diet with balanced amino acids maintained normal estrous cyclicity. These disturbances of the estrous cycle by amino acid deficiency were quickly reversed by the consumption of a normal diet. The continuous anovulatory state in this study is not attributable to a decrease in caloric intake but to an imbalance in the dietary amino acid composition. With a shortage of well-balanced amino acid sources, reproduction becomes risky for both the mother and the fetus. It could be viewed as an adaptation to the diet, diverting resources away from reproduction and reallocating them to survival until well-balanced amino acid sources are found.
Nano-scale measurement of biomolecules by optical microscopy and semiconductor nanoparticles
Taro Ichimura,Takashi Jin,Hideaki Fujita,Hideo Higuchi,Tomonobu M. Watanabe
Frontiers in Physiology , 2014, DOI: 10.3389/fphys.2014.00273
Abstract: Over the past decade, great developments in optical microscopy have made this technology increasingly compatible with biological studies. Fluorescence microscopy has especially contributed to investigating the dynamic behaviors of live specimens and can now resolve objects with nanometer precision and resolution due to super-resolution imaging. Additionally, single particle tracking provides information on the dynamics of individual proteins at the nanometer scale both in vitro and in cells. Complementing advances in microscopy technologies has been the development of fluorescent probes. The quantum dot, a semi-conductor fluorescent nanoparticle, is particularly suitable for single particle tracking and super-resolution imaging. This article overviews the principles of single particle tracking and super resolution along with describing their application to the nanometer measurement/observation of biological systems when combined with quantum dot technologies.
Urinary oxytocin positively correlates with performance in facial visual search in unmarried males, without specific reaction to infant face
Atsuko Saito,Takefumi Kikusui,Kazutaka Mogi,Takashi Higuchi,Toshikazu Hasegawa,Kazuo Hiraki
Frontiers in Neuroscience , 2014, DOI: 10.3389/fnins.2014.00217
Abstract: The neuropeptide oxytocin plays a central role in prosocial and parental behavior in non-human mammals as well as humans. It has been suggested that oxytocin may affect visual processing of infant faces and emotional reaction to infants. Healthy male volunteers (N = 13) were tested for their ability to detect infant or adult faces among adult or infant faces (facial visual search task). Urine samples were collected from all participants before the study to measure the concentration of oxytocin. Urinary oxytocin positively correlated with performance in the facial visual search task. However, task performance and its correlation with oxytocin concentration did not differ between infant faces and adult faces. Our data suggests that endogenous oxytocin is related to facial visual cognition, but does not promote infant-specific responses in unmarried men who are not fathers.
A Scheme for Calculating Atomic Structures beyond the Spherical Approximation  [PDF]
Mitiyasu Miyasita, Katsuhiko Higuchi, Masahiko Higuchi
Journal of Modern Physics (JMP) , 2011, DOI: 10.4236/jmp.2011.25052
Abstract: We present a scheme for calculating atomic single-particle wave functions and spectra with taking into ac-count the nonspherical effect explicitly. The actual calculation is also performed for the neutral carbon atom within the Hartree-Fock-Slater approximation. As compared with the conventional atomic structure of the spherical approximation, the degenerate energy levels are split partially. The ground state values of the total orbital and spin angular momenta are estimated to be both about unity, which corresponds to the term P3PP in the LS-multiplet theory. This means that the nonspherical effect may play an essential role on the description of the magnetization caused by the orbital polarization.
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