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Search Results: 1 - 10 of 53721 matches for " Takahashi Y "
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Oxalate metal complexes in aerosol particles: implications for the hygroscopicity of oxalate-containing particles
T. Furukawa,Y. Takahashi
Atmospheric Chemistry and Physics (ACP) & Discussions (ACPD) , 2011, DOI: 10.5194/acp-11-4289-2011
Abstract: Atmospheric aerosols have both a direct and an indirect cooling effect that influences the radiative balance at the Earth's surface. It has been estimated that the degree of cooling is large enough to weaken the warming effect of carbon dioxide. Among the cooling factors, secondary organic aerosols (SOA) play an important role in the solar radiation balance in the troposphere as SOA can act as cloud condensation nuclei (CCN) and extend the lifespan of clouds because of their high hygroscopic and water soluble nature. Oxalic acid is an important component of SOA, and is produced via several formation pathways in the atmosphere. However, it is not certain whether oxalic acid exists as free oxalic acid or as metal oxalate complexes in aerosols, although there is a marked difference in their solubility in water and their hygroscopicity. We employed X-ray absorption fine structure spectroscopy to characterize the calcium (Ca) and zinc (Zn) in aerosols collected at Tsukuba in Japan. Size-fractionated aerosol samples were collected for this purpose using an impactor aerosol sampler. It was shown that 10–60% and 20–100% of the total Ca and Zn in the finer particles (<2.1 μm) were present as Ca and Zn oxalate complexes, respectively. Oxalic acid is hygroscopic and can thus increase the CCN activity of aerosol particles, while complexes with various polyvalent metal ions such as Ca and Zn are not hygroscopic, which cannot contribute to the increase of the CCN activity of aerosols. Based on the concentrations of noncomplexed and metal-complexed oxalate species, we found that most of the oxalic acid is present as metal oxalate complexes in the aerosols, suggesting that oxalic acid does not always increase the hygroscopicity of aerosols in the atmosphere. Similar results are expected for other dicarboxylic acids, such as malonic and succinic acids. Thus, it is advisable that the cooling effect of organic aerosols should be estimated by including the information on metal oxalate complexes and metal complexes with other dicarboxylic acids in aerosols.
Mirtazapine treatment of diabetic gastroparesis as a novel method to reduce tube-feed residual: a case report
Gooden Janelle Y,Takahashi Paul Y
Journal of Medical Case Reports , 2013, DOI: 10.1186/1752-1947-7-38
Abstract: Introduction Gastroparesis is a common motility disorder that is characterized by delayed gastric emptying in the absence of mechanical obstruction. Diabetes, along with other neuromuscular and infiltrating disorders, can predispose individuals to an increased risk of developing gastroparesis. Gastroparesis can be easily diagnosed through gastric emptying studies but is usually difficult to successfully treat. Therapy usually begins with pro-kinetic and anti-emetic agents. Case presentation Our patient was an 87-year-old African-American woman who was a nursing home resident, with a history of diabetes mellitus type 2 and subarachnoid hemorrhage leading to aphasia, hemiplegia, seizures and dysphagia requiring percutaneous gastric feeds. While at the nursing home, she had recurrent aspiration pneumonia and large tube-feed residuals consistent with a diagnosis of underlying gastroparesis. Her management included metoclopramide and reduced tube-feeding rates, which improved her symptoms. However, within months the aspiration and increased residuals returned. After trials of different medication therapies without success, she started mirtazapine and her residual volume and aspirations decreased with a dose of 15mg nightly. Conclusion In patients with gastroparesis recalcitrant to first line therapies such as metoclopramide, off-label use of mirtazapine may provide adequate non-invasive management of gastroparetic symptoms.
Interacting multiple zero mode formulation and its application to a system consisting of a dark soliton in a condensate
J. Takahashi,Y. Nakamura,Y. Yamanaka
Physics , 2015, DOI: 10.1103/PhysRevA.92.023627
Abstract: To formulate the zero modes in a finite-size system with spontaneous breakdown of symmetries in quantum field theory is not trivial, for in the naive Bogoliubov theory, one encounters difficulties such as phase diffusion, the absence of a definite criterion for determining the ground state, and infrared divergences. A new interacting zero mode formulation that has been proposed for systems with a single zero mode to avoid these difficulties is extended to general systems with multiple zero modes. It naturally and definitely gives the interactions among the quantized zero modes, the consequences of which can be observed experimentally. In this paper, as a typical example, we consider an atomic Bose-Einstein condensed system with a dark soliton that contains two zero modes corresponding to spontaneous breakdown of the U(1) gauge and translational symmetries. Then we evaluate the standard deviations of the zero mode operators and see how the mutual interaction between the two zero modes affects them.
Dynamical Instability Induced by Zero Mode Under Symmetry Breaking External Perturbation
J. Takahashi,Y. Nakamura,Y. Yamanaka
Physics , 2013, DOI: 10.1016/j.aop.2014.05.004
Abstract: A complex eigenvalue in the Bogoliubov-de Gennes equations for a stationary Bose-Einstein condensate in ultracold atomic system indicates the dynamical instability of the system. We also have the modes with zero eigenvalues for the condensate, called the zero modes, which originate from the spontaneous breakdown of symmetries. Although the zero modes are suppressed in many theoretical analyses, we take account of them in this paper and argue that a zero mode can change into one with a pure imaginary eigenvalue by applying a symmetry breaking external perturbation potential. This emergence of a pure imaginary mode adds a new type of scenario of dynamical instability to that characterized by complex eigenvalue of the usual excitation modes. For illustration, we deal with two one-dimensional homogeneous Bose-Einstein condensate systems with a single dark soliton under a respective perturbation potential, breaking the invariance under translation, to derive pure imaginary modes.
Protection of mice from LPS-induced shock by CD14 antisense oligonucleotide.
Furusako S,Takahashi T,Mori S,Takahashi Y
Acta Medica Okayama , 2001,
Abstract: CD14 is a pattern recognition receptor on myeloid cells and plays a pivotal role in an innate immune system that is responsible for Gram-negative and Gram-positive bacteria infection. Lipopolysaccharide (LPS), a cell wall component of Gram-negative bacteria, can induce production of a large quantity of proinflammatory cytokines into the circulation mediated by CD14-mediated macrophages and monocytes. These cytokines eventually cause septic shock. Several in vitro and in vivo studies have shown that suppression of a CD14 function by a CD14 antibody led to an inhibition of the production of proinflammatory cytokines such as TNF-alpha, IL-1 beta, and IL-8. In the present study, we found that CD14 antisense oligonucleotide (ODN) can prevent lethal LPS shock in D-galactosamine-sensitized mice. This ODN inhibited CD14 expression in a mouse macrophage cell line, RAW264.7, and suppressed production of TNF-alpha in LPS-stimulated RAW264.7 cells. Furthermore, we designed a consensus antisense ODN that could hybridize human and mouse CD14 RNA, and we evaluated its efficacy. The consensus antisense ODN rescued mice primed with Mycobacterium bovis bacillus Calmette-Guerin (BCG) from the LPS-induced lethal shock. In this model, the CD14 antisense ODN down-regulated LPS-elicited CD14 expression in the liver, resulting in a decrease in LPS-induced TNF-alpha production. These findings suggest that the CD14 antisense ODN is distributed in the liver and efficiently suppresses LPS-induced TNF-alpha production by reducing CD14 expression on Kupffer cells. This CD14 antisense ODN may be useful for the development of a therapeutic agent against sepsis and septic shock.
Comparative effect of clopidogrel plus aspirin and aspirin monotherapy on hematological parameters using propensity score matching
Hayasaka M,Takahashi Y,Nishida Y,Yoshida Y
Vascular Health and Risk Management , 2013,
Abstract: Masatoshi Hayasaka,1 Yasuo Takahashi,2 Yayoi Nishida,2 Yoshikazu Yoshida,1 Shinji Hidaka,3 Satoshi Asai41Department of Pharmacy, Nihon University Itabashi Hospital, Tokyo, 2Division of Genomic Epidemiology and Clinical Trials, Clinical Trials Research Center, Nihon University School of Medicine, Tokyo, 3Laboratory of Pharmaceutical Regulatory Science, Department of Pharmacy, School of Pharmacy, Nihon University, Chiba, 4Division of Pharmacology, Department of Biomedical Sciences, Nihon University School of Medicine, Tokyo, JapanBackground: Clopidogrel and aspirin are antiplatelet agents that are recommended to reduce the risk of recurrent stroke and other cardiovascular events. Dual antiplatelet therapy with clopidogrel and aspirin has been shown to increase the risk of hemorrhage, but the effects of the drugs on laboratory parameters have not been well studied in real-world clinical settings. Therefore, we evaluated and compared the effects of combination therapy with clopidogrel plus aspirin and aspirin monotherapy on laboratory parameters.Methods: We used data from the Nihon University School of Medicine Clinical Data Warehouse obtained between November 2004 and May 2011 to identify cohorts of new users (n = 130) of clopidogrel (75 mg/day) plus aspirin (100 mg/day) and a propensity score matched sample of new users (n = 130) of aspirin alone (100 mg/day). We used a multivariate regression model to compare serum levels of creatinine, aspartate aminotransferase, and alanine aminotransferase, as well as hematological parameters including hemoglobin level, hematocrit, and white blood cell, red blood cell, and platelet counts up to 2 months after the start of administration of the study drugs.Results: There were no significant differences for any characteristics and baseline laboratory parameters between users of clopidogrel plus aspirin and users of aspirin alone. Reductions in white blood cell and red blood cell counts, hemoglobin levels, and hematocrit in users of clopidogrel plus aspirin were significantly greater than those in users of aspirin alone.Conclusion: Our findings suggest that adverse hematological effects may be greater with combination clopidogrel plus aspirin therapy than with aspirin monotherapy.Keywords: clopidogrel, aspirin, laboratory parameter, antiplatelet therapy, propensity score matching
Valley Polarization in Si(100) at Zero Magnetic Field
K. Takashina,Y. Ono,A. Fujiwara,Y. Takahashi,Y. Hirayama
Physics , 2006, DOI: 10.1103/PhysRevLett.96.236801
Abstract: The valley splitting, which lifts the degeneracy of the lowest two valley states in a SiO$_2$/(100)Si/SiO$_2$ quantum well is examined through transport measurements. We demonstrate that the valley splitting can be observed directly as a step in the conductance defining a boundary between valley-unpolarized and polarized regions. This persists to well above liquid helium temperature and shows no dependence on magnetic field, indicating that single-particle valley splitting and valley-polarization exist in (100) silicon even at zero magnetic field.
A multi-institutional and interdisciplinary approach to the assessment of vulnerability and adaptation to climate change in the Peruvian Central Andes: problems and prospects
Y. Silva, K. Takahashi,R. Chávez
Advances in Geosciences (ADGEO) , 2008,
Abstract: Monthly precipitation data from the period of 1970 to 2004 from 38 meteorological stations in the Mantaro river basin were used to classify the rainy seasons (September–April) of each year into anomalously dry or wet, and to determine the basin-wide extent of the anomalies based on the Standardized Precipitation Index (SPI). The wet periods mostly occurred in the early 1970's and during the first half of the 1980's, except for the event that occurred in the 1993/94 period which was the strongest and most generalized in the analyzed period. The dry periods occurred mostly during the second half of the 1980's and the 1990's. Consistent with this, a negative trend in precipitation of 2% per decade was found for the rainy season, due mainly to a stronger trend ( 4%/decade) during the peak phase (January–March). Despite previously reported significant negative correlations between El Ni o-Southern Oscillation (ENSO) and rainfall during the peak of the rainfall season, the similar amplitude variability of precipitation during the onset phase of the rainfall season (September–December), which is uncorrelated with ENSO, participate to the reduction of the absolute correlation for the full rainfall season. Correlations between rainfall in the Mantaro basin and sea surface temperature (SST) in the tropical Atlantic are significant only near the end of the rainy season, with more rain associated with a weaker north-south difference in SST in the tropical Atlantic.
Possible Involvement of DNA Topoisomerase II Enzyme in the Process of Meiotic Arrest in Mouse Metaphase II Oocytes
A. S. Elsheikh,Y. Takahashi,H. Kanagawa
Journal of Animal and Veterinary Advances , 2012,
Abstract: The effects of etoposide supplementation to mouse gametes co-culture medium on fertilization rate, nuclear events and development to the blastocyst stage were investigated. In vivo matured mouse oocytes were co-cultured with sperms in TYH medium supplemented with 50 ?g/ml etoposide an specific DNA topoisomerase II (top II) blocker. Experiment 1 evaluated the effects of top II blocker on fertilization rate and nuclear events in fertilized oocytes whole-mounted 5 hr after gametes co-culture. Top II blocking decreased the fertilization rate significantly (p<0.01) as compared with the control. Furthermore, the fertilized oocytes were blocked at the metaphase II stage and the extrusion of the second polar body an the formation of the female and male pronuclei were completely inhibited. Experiment II examined the ability of the oocytes fertilized in the presence of top II blocker to cleave and develop to the blastocyst stage in vitro. The cleavage rate of oocytes fertilized in the presence of etoposide was significantly lower (p<0.001) than the control (11% vs 86.3%; respectively). Non of the eggs fertilized in the presence of etoposide (n=154) developed beyond the 2-cell stage, whereas (76.3%) of the control (n=145) developed to the blastocyst stage. It is concluded that the use of top II blocker (etoposide) in mouse gametes co-culture medium inhibits exit from meiotic arrest after sperm penetration. Thus, suggesting a possible involvement of top II in meiotic arrest.
Cytomegalovirus retinitis treated with valganciclovir in Wegener’s granulomatosis
Kabata Y, Takahashi G, Tsuneoka H
Clinical Ophthalmology , 2012, DOI: http://dx.doi.org/10.2147/OPTH.S31130
Abstract: omegalovirus retinitis treated with valganciclovir in Wegener’s granulomatosis Case report (2192) Total Article Views Authors: Kabata Y, Takahashi G, Tsuneoka H Published Date March 2012 Volume 2012:6 Pages 521 - 523 DOI: http://dx.doi.org/10.2147/OPTH.S31130 Received: 23 February 2012 Accepted: 05 March 2012 Published: 27 March 2012 Yoshiaki Kabata1, Genichiro Takahashi1, Hiroshi Tsuneoka2 1Department of Ophthalmology, Jikei University School of Medicine, Katsushika Medical Center, Katsushika, Tokyo, Japan; 2Department of Ophthalmology, Jikei University School of Medicine, Minato, Tokyo, Japan Abstract: A case of cytomegalovirus (CMV) retinitis in a patient with Wegener’s granulomatosis treated with oral valganciclovir as maintenance therapy is reported. A 68-year-old male patient with anti-proteinase-3 ANCA-positive Wegener’s granulomatosis who was receiving immunosuppressive therapy with methylprednisolone, cyclophosphamide, and azathioprine developed CMV retinitis. The patient received intravenous ganciclovir as induction therapy and oral valganciclovir as maintenance therapy. The patient responded to treatment and showed no recurrence for 8 months. There were no serious adverse effects associated with oral valganciclovir. Oral valganciclovir is convenient and effective for the management of CMV retinitis in the patient with Wegener’s granulomatosis.
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