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Operationally Simple Enantioselective Silane Reduction of Ketones by the [Ir(OMe)(cod)]₂/Azolium Catalytic System

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International Journal of Organic Chemistry 2024年第1期14卷 1-19页

作者： Satoshi sakaguchi Chika Nagao Ryo Ichihara Shogo Matsuo Department of Chemistry and Materials Engineering Faculty of Chemistry Materials and Bioengineering Kansai University Suita Japan

An operationally simple protocol was designed for the enantioselective silane reduction (ESR) of ketones using air- and moisture-stable [Ir(OMe)(cod)]2 (cod = 1,5-cyclooctadiene) (3) as a metal catalyst precursor. This reaction was driven by chiral hydroxyamide-functionalized azolium salt 2. The catalytic ESR reaction could be performed under benchtop conditions at room temperature. Treatment of 2 with 3 in THF yielded the monodentate IrCl(NHC)(cod) (NHC = N-heterocyclic carbene) complex 4 in 93% yield, herein the anionic methoxy ligand of 3 serves as an internal base that deprotonates the azolium ring of 2. The well-defined Ir complex 4 catalyzed the ESR reaction of propiophenone (6) with (EtO)2MeSiH using the pre-mixing reaction procedure. Based on this success, the catalytic ESR reaction was designed and implemented using an in situ-generated NHC/Ir catalyst derived from 2 and 3. Thus, a wide variety of aryl ketones could be reduced to the corresponding optically active alcohols in moderate to excellent stereoselectivities at room temperature without temperature control. Since the high catalytic activity of 3 was observed, we next evaluated several other transition metal catalyst precursors for the catalytic ESR reaction under the influence of 2. This evaluation revealed that Ir(acac)(cod) (acac = acetylacetonate) (28) and [IrCl(cod)]2 (5) can be successfully used as metal catalyst precursors in the ESR reaction.

关键词： Asymmetric Catalysis Enantioselective Reduction Hydrosilylation Reaction N-Heterocyclic Carbene Iridium

Unroofing Technique for Anomalous Origin of the Left Coronary Artery from the Right Sinus of Valsalva: Report of a Case

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World Journal of Cardiovascular Surgery 2024年第6期14卷 69-77页

作者： Keisuke Morimoto Futoshi Kobayashi Hiromu Horie Yuki sakaguchi Einosuke Mizuta Department of Cardiovascular Surgery Sanin Rosai Hospital Yonago Japan Department ofCardiology Sanin Rosai Hospital Yonago Japan

Anomalous origin of the left coronary artery (AOLCA) from the right sinus of Valsalva constitutes a rare congenital coronary artery anomaly. Patients with an anomalous left main coronary artery face a significantly higher risk of sudden cardiac death compared to those with an anomalous right coronary artery. The anomalous coronary artery traversing between the ascending aorta and the pulmonary artery markedly heightens the risk of myocardial ischemia, arrhythmia, and sudden death. Symptomatic patients often exhibit a longer intramural course of the coronary artery, which may necessitate earlier intervention or influence the choice of surgical repair method. Surgical intervention is advocated for patients with this anomaly, even in the absence of symptoms. For anomalous aortic origin of a coronary artery from the opposite sinus of Valsalva with an intramural course, coronary unroofing is the preferred revascularization procedure. This report presents a case of AOLCA originating from the right sinus of Valsalva, treated surgically using the unroofing technique for the aortic intramural segment of the anomalous coronary artery traversing between the great vessels. The unroofing technique is recommended for treating AOLCA with an extensive intramural course that does not involve the commissure.

关键词： Unroofing Technique Anomaly of Coronary Artery Anomalous Origin of Left Coronary Artery

Best mix of primary energy resources by renewable energy and fossil fuel with CCS in view of security,stability and sustainability——A vision on hydrogen supply chain by organic chemical hydride method

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Science China(Technological Sciences) 2010年第1期53卷 62-68页

作者： Junichi sakaguchi Research Institute of Technology Innovation & Strategy of Chiyoda Corporation 2-12-1TsurumichuoTsurumi-kuYokohama230-8601Japan

The best mix scenario by renewable energy and fossil fuel with or without CCS(Carbon Dioxide Capture and Storage) would be a solution to compromise Greenhouse Gases emission issue caused by carbon dioxide(CO2),and depletion of crude oil and natural gas *** fossil fuel with pre-combustion CCS means hydrogen manufacturing and also hydrogen can be produced via electrolysis with renewable energy,it is desirable to establish transportation and storage systems of hydrogen as a clean *** this paper a vision on Hydrogen Supply Chain by Organic Chemical Hydride(OCH) Method as well as comparison of CCS configuration are discussed.

关键词： pre-combustion CCS compressors and pumps for CCS Hydrogen Supply Chain Organic Chemical Hydride Method

Multi-point Optimization of Recirculation Flow Type Casing Treatment in Centrifugal Compressors

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Journal of Thermal Science 2016年第3期25卷 231-241页

作者： Min Thaw Tun Daisaku sakaguchi Nagasaki University 1-14 Bunkyo-machi 852-8521 Nagasaki Japan

High-pressure ratio and wide operating range are highly required for a turbocharger in diesel engines. A recirculation flow type casing treatment is effective for flow range enhancement of centrifugal compressors. Two ring grooves on a suction pipe and a shroud casing wall are connected by means of an annular passage and stable recirculation flow is formed at small flow rates from the downstream groove toward the upstream groove through the annular bypass. The shape of baseline recirculation flow type casing is modified and optimized by using a multi-point optimization code with a metamodel assisted evolutionary algorithm embedding a commercial CFD code CFX from ANSYS. The numerical optimization results give the optimized design of casing with improving adiabatic efficiency in wide operating flow rate range. Sensitivity analysis of design parameters as a function of efficiency has been performed. R is found that the optimized casing design provides optimized recirculation flow rate, in which an increment of entropy rise is minimized at grooves and passages of the rotating impeller.

关键词： Centrifugal Compressor Casing Treatment Multi-point Optimization Turbocharger

Contribution of adult-born neurons to memory consolidation during rapid eye movement sleep

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Neural Regeneration Research 2022年第2期17卷 307-308页

作者： Akinobu Ohba Masanori sakaguchi International Institute for Integrative Sleep Medicine(WPI-IIIS) University of TsukubaTsukubaIbarakiJapan

Introduction: Memory consolidation stabilizes newly acquired memories by integrating them into pre-existing memory networks, which is thought to occurvia changes in synaptic strength. Sleep may influence memory consol... 详细信息

关键词： strength. sleep integrating

Markov decision processes associated with two threshold probability criteria

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控制理论与应用（英文版） 2013年第4期11卷 548-557页

作者： Masahiko sakaguchi Yoshio OHTSUBO Department of Mathematics Faculty of ScienceKochi University

This paper deals with Markov decision processes with a target set for nonpositive rewards. Two types of threshold probability criteria are discussed. The first criterion is a probability that a total reward is not greater than a given initial threshold value, and the second is a probability that the total reward is less than it. Our first （resp. second） optimizing problem is to minimize the first （resp. second） threshold probability. These problems suggest that the threshold value is a permissible level of the total reward to reach a goal （the target set）, that is, we would reach this set over the level, if possible. For the both problems, we show that 1） the optimal threshold probability is a unique solution to an optimality equation, 2） there exists an optimal deterministic stationary policy, and 3） a value iteration and a policy space iteration are given. In addition, we prove that the first （resp. second） optimal threshold probability is a monotone increasing and right （resp. left） continuous function of the initial threshold value and propose a method to obtain an optimal policy and the optimal threshold probability in the first problem by using them in the second problem.

关键词： Markov decision process Minimizing risk model Threshold probability Policy space iteration

Velocity and Size of Droplets in Dense Region of Diesel Fuel Spray on Transient Needle Opening Condition

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Journal of Thermal Science 2005年第2期14卷 181-186页

作者： Hironobu UEKI Masahiro ISHIDA Daisaku sakaguchi Nagasaki University 1-14 Bunkyo-machi Nagasaki 852-8521JapanNagasaki University 1-14 Bunkyo-machiNagasaki 852-8521JapanNagasaki University 1-14 Bunkyo-machiNagasaki 852-8521Japan

In order to investigate the effect of transient needle opening on early stage of spray behavior, simultaneous measurements of velocity and size of droplet were conducted by a newly developed laser 2-focus velocimeter (L2F). The micro-scale probe of the L2F was consisted of two foci with a distance of 36μm. The tested nozzle had a single hole with a diameter of 0.2 mm. The measurements of injection pressure, needle lift, and crank angle were synchronized with the spray measurement by the L2F at the position 10 mm downstream from the nozzle exit. It has been clearly shown that the velocity and size of droplet increase with needle valve opening and that the probability density distribution of droplet size can be fitted to the Nukiyama-Tanasawa distribution under the transient needle opening condition.

关键词： droplet disintegration optical characterization laser 2-focus velocimeter.

Sorbitol-based osmotic diarrhea:Possible causes and mechanism of prevention investigated in rats

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World Journal of Gastroenterology 2006年第47期12卷 7635-7641页

作者： Md Shahidul Islam Ei sakaguchi Laboratory of Animal Nutri-tion Faculty of Agriculture Okayama University 1-1-1 Tsushima-naka Okayama City 700-8530 Japan

AIM: To study the possible causes of sorbitol (S)-based diarrhea and its mechanism of reduction by rice gruel (RG) in cecectomized rats. METHODS: S was dissolved either in distilled water or in RG (50 g/L) and ingested as a single oral dose (1.2 g/kg body mass, containing 0.5 g/L phenol red as a re-covery marker) by S (control) and S + RG groups (n = 7), respectively. This dose is over the laxative dose for hu-mans. Animals were sacrificed exactly 1 h after dose in-gestion, without any access to drinking water. The whole gastro-intestinal tract was divided into seven segments and sampled to analyze the S and marker remaining in its ***: Gastric-emptying and intestinal transit were comparatively slower in the S + RG group. Also, the S absorption index in the 3rd and last quarter of the small intestine (24.85 ± 18.88% vs 0.0 ± 0.0% and 39.09 ± 32.75% vs 0.0 ± 0.0%, respectively, P < 0.05) was sig-nificantly higher in the S + RG group than in the control group. The S absorption index and the intestinal fluid volume are inversely related to each other. CONCLUSION: The intestinal mal-absorption of S is the main reason for S-based osmotic diarrhea. Where RG en-hanced the absorption of S through passive diffusion, the degree of diarrhea was reduced in cecectomized rats.

关键词： Cecectomized rat Sorbitol Diarrhea Rice gruel Phenol red

Global Search of a Three-dimensional Low Solidity Circular Cascade Diffuser for Centrifugal Blowers by Meta-model Assisted Optimization

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Journal of Thermal Science 2018年第2期27卷 111-116页

作者： Daisaku sakaguchi Daiki Sakue Min Thaw Tun Nagasaki University 1-14 Bunkyo-machi Nagasaki 852-8521 Japan Yangon Technological University Insein Road East Gyogone Insein Township Yangon

A three-dimensional blade of a low solidity circular cascade diffuser in centrifugal blowers is designed by means of a multi-point optimization technique. The optimization aims at improving static pressure coefficient at a design point and at a small flow rate condition. Moreover, a clear definition of secondary flow expressed by positive radial velocity at hub side is taken into consideration in constraints. The number of design parameters for three-dimensional blade reaches to 10 in this study, such as a radial gap, a radial chord length and mean camber angle distribution of the LSD blade with five control points, control point between hub and shroud with two design freedom. Optimization results show clear Pareto front and selected optimum design shows good improvement of pressure rise in diffuser at small flow rate conditions. It is found that three-dimensional blade has advantage to stabilize the secondary flow effect with improving pressure recovery of the low solidity circular cascade diffuser.

关键词： Multi-point optimization Low solidity cascade diffuser Flow range enhancement