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Search Results: 1 - 10 of 1356 matches for " Masashi Nakazawa "
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Surface Force Analysis of Pyrite (FeS2): Its Reactivity to Amino Acid Adsorption  [PDF]
Narangerel Ganbaatar, Nina Matsuzaki, Yuya Nakazawa, Rehana Afrin, Masashi Aono, Taka-aki Yano, Tomohiro Hayashi, Masahiko Hara
Advances in Materials Physics and Chemistry (AMPC) , 2016, DOI: 10.4236/ampc.2016.67018
Abstract: It is well known that mineral surfaces play an important role as catalysts for abiotic polymerization of amino acids to form peptides, which are the main components of the first self-replicating system. Understanding the mechanism behind the adsorption of simple amino acids on mineral surfaces is a topic of great interest not only in field of prebiotic evolution and but also in many other branches of material sciences. Various clay minerals have been suggested for studying how organic molecules were first synthesized in a prebiotic “inorganic” environment. Among them, pyrite (FeS2) is one of the most potential minerals as it possesses a highly reactive surface to drive molecular adsorption in prebiotic chemistry reactions. Recent theoretical experiments suggest that amino acids are adsorbed on the pyrite surface depending on its surface structures. However, these results have not been tested experimentally, and the exact mechanism of the specific interactions on this mineral has not been fully resolved yet at the molecular level. In this work, through quantitative force analysis with atomic force microscope (AFM) in which a single amino acid residue was mounted on the tip apex of AFM probe, we were able to find the reaction sites and study the interaction forces between the amino acid and the pyrite surface. Our results of Raman spectroscopic studies and force measurements with a well-designed AFM probe demonstrated for the first time that pyrite provided higher adsorption probabilities of amino acid residues for the chemical reactions at surfaces.
Intraspecific Relationships and Variation of Two Lefua Species (Balitoridae, Cypriniformes) in the Tokai Region, Honshu, Japan  [PDF]
Jun-Ichi Miyazaki, Seiya Hida, Takurou Ozaki, Yuichirou Tabata, Misaki Iwata, Masashi Nakazawa, Youki Fukasawa, Tomonari Asaka
Journal of Water Resource and Protection (JWARP) , 2017, DOI: 10.4236/jwarp.2017.92016
Abstract: Two species Lefua echigonia and Lefua sp. 2 of the eight-barbel loach inhabit the Tokai region of Honshu, Japan. We determined sequences of the mitochondrial D-loop region to elucidate intraspecific phylogenetic relationships and variation in these two species. Lefua sp. 2 represented high intraspecific genetic similarity and complicated haplotype network, but three assemblages were recognized, including specimens mainly from Yahagi, Toyo, and Tenryu River systems, respectively, and named Groups 1 to 3. Divergence of Group 1 from the others was marginally supported, but Group 2 was paraphyletic to Group 3, suggesting the existence of two populations, i.e. Yahagi River population and Toyo-Tenryu River population. Lefua echigonia also represented high intraspecific genetic similarity, and two assemblages with slight genetic differentiation were discernible, including specimens from Shizuoka and southeastern Aichi prefectures and those from northwestern Aichi, Gifu, and Mie prefectures, respectively, and named Groups A and B. Star-like relationships of haplotypes suggested the dispersal origin located in eastern Aichi prefecture. The two species are threatened to extinction and thus we proposed evolutionary significant units for conservation.
Does the Method of Amalgamation Affect Cost Inefficiency of the New Municipalities?  [PDF]
Katsuyoshi Nakazawa
Open Journal of Applied Sciences (OJAppS) , 2014, DOI: 10.4236/ojapps.2014.44015
Abstract: Municipal amalgamation has been done in many countries in recent years as the result of a push to enlarge the size and coverage of local government units, which in turn is driven mainly by the prospect of economies of scale. However, while municipality amalgamation or boundary reform raises population size, it introduces organizational changes in the local government that might increase administrative inefficiency. The choice for the method of integration of administrative functions before amalgamation might affect to public expenditure after amalgamation. This study uses Japanese municipal-level data and argues for a relation between the choice for the method of integration of administrative functions and cost inefficiency after amalgamation. The results show that the fully distributed facility method is more likely to be adopted in a larger administrative jurisdiction and in one with large differences in finances or political structures between amalgamated sub-regions. Moreover, the results of stochastic frontier regression show that new municipality adopting fully distributed facility method can possibly increase inefficiency by expanding organizational slack because the new administration system will be insufficient integration of administrative functions.
Evaluation of the Effects of Acupuncture on Blood Flow in Humans with Ultrasound Color Doppler Imaging
Shin Takayama,Masashi Watanabe,Hiroko Kusuyama,Satoru Nagase,Takashi Seki,Toru Nakazawa,Nobuo Yaegashi
Evidence-Based Complementary and Alternative Medicine , 2012, DOI: 10.1155/2012/513638
Abstract: Color Doppler imaging (CDI) can be used to noninvasively create images of human blood vessels and quantitatively evaluate blood flow in real-time. The purpose of this study was to assess the effects of acupuncture on the blood flow of the peripheral, mesenteric, and retrobulbar arteries by CDI. Statistical significance was defined as values less than 0.05. Blood flow in the radial and brachial arteries was significantly lower during needle stimulation on LR3 than before in healthy volunteers, but was significantly higher after needle stimulation than before. LR3 stimulation also resulted in a significant decrease in the vascular resistance of the short posterior ciliary artery and no significant change of blood flow through the superior mesenteric artery (SMA) during acupuncture. In contrast, ST36 stimulation resulted in a significant increase in blood flow through the SMA and no significant change in the vascular resistance of the retrobulbar arteries. Additionally, acupuncture at previously determined acupoints in patients with open-angle glaucoma led to a significant reduction in the vascular resistance of the central retinal artery and short posterior ciliary artery. Our results suggest that acupuncture can affect blood flow of the peripheral, mesenteric, and retrobulbar arteries, and CDI can be useful to evaluate hemodynamic changes by acupuncture.
Spinal subarachnoid hematoma in a woman with HELLP syndrome: a case report
Hisako Fujimaki, Toshiyuki Nakazawa, Masaki Ueno, Takayuki Imura, Wataru Saito, Naonobu Takahira, Masashi Takaso
Journal of Medical Case Reports , 2012, DOI: 10.1186/1752-1947-6-152
Abstract: At 29 gestational weeks, a 35-year-old Japanese woman was diagnosed with HELLP syndrome based on bilateral leg paralysis, diminished sensation and reflexes, and laboratory findings. The pregnancy was immediately brought to an end by Cesarean delivery. Post-operatively, an MRI scan revealed a space-occupying lesion in her thoracic spinal canal. Emergency decompression was followed by total laminectomy. A subarachnoid hematoma, partially extending as far as the ventral side, was removed. After thorough washing and drain placement, the operation was completed with the suturing of artificial dura mater. Eight months post-operatively, her lower extremity sensation had improved to a score of 8 out of 10, but improvements in her muscular strength were limited to slight gains in her toes. MRI scans taken two months post-operatively revealed edematous spinal cord changes within her medulla.A subarachnoid hematoma during pregnancy is extremely rare, possibly due to increased coagulability during pregnancy. However, this complication is potentially devastating should a clot compress the spinal cord or cauda equina. While several causes of hematoma have been proposed, we speculate that the factors underlying hemorrhagic diathesis in our case were the decreased platelet count characteristic of HELLP syndrome and vascular fragility due to elevated estrogen levels, in addition to increased abdominal pressure during pregnancy and pressure from the gravid uterus resulting in ruptured vessels around the spinal cord. In cases displaying a progressive lesion and severe neurological signs, prompt decompression is crucial.
Distribution of Deviation Distance to Alternative Fuel Stations  [PDF]
Masashi Miyagawa
American Journal of Operations Research (AJOR) , 2013, DOI: 10.4236/ajor.2013.33033
Abstract: This paper derives the distribution of the deviation distance to visit an alternative fuel station. Distance is measured as the Euclidean distance on a continuous plane. The distribution explicitly considers the vehicle range and whether the round trip between origin and destination can be made. Three cases are examined: fuel is available at both origin and destination, fuel is available at either origin or destination, and fuel is available at neither origin nor destination. The analytical expressions for the distribution demonstrate how the vehicle range, the shortest distance, and the refueling availability at origin and destination affect the deviation distance. The distribution will thus be useful to estimate the number of vehicles refueled at a station.

Weak Values Influenced by Environment  [PDF]
Masashi Ban
Journal of Modern Physics (JMP) , 2013, DOI: 10.4236/jmp.2013.411A1001

A weak value of an observable is studied for a quantum system which is placed under the influence of an environment, where a quantum system irreversibly evolves from a pre-selected state to a post-selected state. A general expression for a weak value influenced by an environment is provided. For a Markovian environment, the weak value is calculated in terms of the predictive and retrodictive density matrices, or by means of the quantum regression theorem. For a non-Markovian environment, a weak value is examined by making use of exactly solvable models. It is found that although the anomalous property is significantly suppressed by a Markovian environment, it can survive a non-Markovian environment.

Visceral Ischemia Caused by Extra-Anatomical Bypass for Coral Reef Aorta  [PDF]
Masashi Kawabori
World Journal of Cardiovascular Surgery (WJCS) , 2015, DOI: 10.4236/wjcs.2015.57012
Abstract: A 72-year-old woman was presented with intermittent claudication of bilateral lower extremities, refractory hypertension, and mild renal impairment. Computed tomographic angiography showed severe aortic stenosis caused by calcifications protruding into the aortic lumen proximal and distal to the visceral and renal branches, so-called coral reef aorta. An axillo-iliac bypass was performed. Postoperatively, the patient developed ileus and acute renal failure, presumably caused by a steal phenomenon to the lower extremities. Endovascular stenting of the aorta increased forward blood flow and dramatically improved the patient’s condition. This case study illustrates potential hemodynamic complications after extra-anatomical axillo-iliac bypass for coral reef aorta.
Aortic Valve Replacement in Bicuspid Aortic Valve with a Single Coronary Artery  [PDF]
Masashi Kawabori
World Journal of Cardiovascular Surgery (WJCS) , 2015, DOI: 10.4236/wjcs.2015.512020
Abstract: Coronary artery anomalies combined with bicuspid aortic valve are rare but cause perioperative complications if not detected on time. Because anomalous coronary arteries vary with respect to the ostium’s origin and transverse route, the precise anatomy should be identified preoperatively and the procedure modified. We describe a severely stenotic bicuspid aortic valve and anomalous coronary artery corrected successfully with a modified valve replacement procedure, illustrating the importance of analyzing coronary anatomy preoperatively, regardless of age, to avoid occluding an anomalous artery’s ostium and to address the anomalies. We describe our modified procedure based on the artery’s location for a safe operation.
Effects of Calcium Ion, Calpains, and Calcium Channel Blockers on Retinitis Pigmentosa
Mitsuru Nakazawa
Journal of Ophthalmology , 2011, DOI: 10.1155/2011/292040
Abstract: Recent advances in molecular genetic studies have revealed many of the causative genes of retinitis pigmentosa (RP). These achievements have provided clues to the mechanisms of photoreceptor degeneration in RP. Apoptosis is known to be a final common pathway in RP and, therefore, a possible therapeutic target for photoreceptor rescue. However, apoptosis is not a single molecular cascade, but consists of many different reactions such as caspase-dependent and caspase-independent pathways commonly leading to DNA fractionation and cell death. The intracellular concentration of calcium ions is also known to increase in apoptosis. These findings suggest that calpains, one of the calcium-dependent proteinases, play some roles in the process of photoreceptor apoptosis and that calcium channel antagonists may potentially inhibit photoreceptor apoptosis. Herein, the effects of calpains and calcium channel antagonists on photoreceptor degeneration are reviewed.
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