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Search Results: 1 - 10 of 593 matches for " Hirotsugu Ohashi "
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Development of a Retractor Holding Device to Reduce the Manpower in Total Hip Arthroplasty through Direct Anterior Approach  [PDF]
Hirotake Yo, Hirotsugu Ohashi, Ryo Sugama, Tessyu Ikawa
Open Journal of Orthopedics (OJO) , 2016, DOI: 10.4236/ojo.2016.62004
Abstract: Direct anterior approach (DAA) for total hip arthroplasty (THA) is a minimally invasive technique. In this approach, two assistants are necessary. We developed a retractor holding device called “Spider arm” to replace an assistant in the contra-lateral side. In this study, we investigated the usefulness of Spider arm in THA through direct anterior approach. 20 hips were operated without Spider arm and 21 hips were operated with Spider arm. The surgery time and the blood loss were compared. The cup position and leg length discrepancy were measured on radiography. There was no statistical significance between two groups in all parameters. No clinical complications were reported. With Spider arm, DAA-THA could be performed by two surgeons without deterioration of the surgery time and blood loss. The accuracy of cup position and leg length discrepancy was not affected. Spider arm can contribute to reducing the manpower in DAA-THA.
Pseudoaneurysm Accompanied by Crowe Type IV Developmental Dysplasia of the Hip: A Case Report
Hirotake Yo,Hirotsugu Ohashi,Fumiaki Inori,Yoshiaki Okajima,Yoshio Matsui,Kosuke Shintani
Case Reports in Orthopedics , 2012, DOI: 10.1155/2012/973489
Abstract: We report the case of a 72-year-old woman whose pseudoaneurysm was difficult to diagnose and treat. The patient had a history of congenital dislocated hip and was undergoing anticoagulation therapy with warfarin due to the mitral valve replacement. Her chief complaint was pain and enlargement of the left buttock, and the laboratory tests revealed severe anemia. However, her elderly depression confused her chief complaint, and she was transferred to a psychiatric hospital. Two months after the onset of the symptoms, she was finally diagnosed with a pseudoaneurysm by contrast-enhanced CT and angiography. IDC coils were used for embolization. A plain CT showed hemostasis as well as a reduced hematoma at 2 months after the embolization. The possible contributing factors for the pseudoaneurysm included bleeding due to warfarin combined with an intramuscular hematoma accompanied by Crowe type IV developmental dysplasia of the hip that led to an arterial rupture by impingement between pelvis and femoral head. Since the warfarin treatment could not be halted due to the valve replacement, embolization was chosen for her treatment, and the treatment outcome was favorable.
Pseudoaneurysm Accompanied by Crowe Type IV Developmental Dysplasia of the Hip: A Case Report
Hirotake Yo,Hirotsugu Ohashi,Fumiaki Inori,Yoshiaki Okajima,Yoshio Matsui,Kosuke Shintani
Case Reports in Orthopedics , 2012, DOI: 10.1155/2012/973489
Abstract: We report the case of a 72-year-old woman whose pseudoaneurysm was difficult to diagnose and treat. The patient had a history of congenital dislocated hip and was undergoing anticoagulation therapy with warfarin due to the mitral valve replacement. Her chief complaint was pain and enlargement of the left buttock, and the laboratory tests revealed severe anemia. However, her elderly depression confused her chief complaint, and she was transferred to a psychiatric hospital. Two months after the onset of the symptoms, she was finally diagnosed with a pseudoaneurysm by contrast-enhanced CT and angiography. IDC coils were used for embolization. A plain CT showed hemostasis as well as a reduced hematoma at 2 months after the embolization. The possible contributing factors for the pseudoaneurysm included bleeding due to warfarin combined with an intramuscular hematoma accompanied by Crowe type IV developmental dysplasia of the hip that led to an arterial rupture by impingement between pelvis and femoral head. Since the warfarin treatment could not be halted due to the valve replacement, embolization was chosen for her treatment, and the treatment outcome was favorable. 1. Introduction Anticoagulation therapy is used to treat and prevent thromboembolic diseases such as myocardial infarction and cerebral infarction, as well as to prevent catheter occlusion. However, hemorrhagic events are a severe adverse effect of anticoagulant therapy. We report a case of pseudoaneurysm in a patient with Crowe type IV developmental dysplasia of the hip undergoing anticoagulation therapy. 2. Case Presentation The patient was a 72-year-old female with bilateral Crowe type IV developmental dysplasia of the hip. Her chief complaint was enlargement and pain in her left buttock. Her history included congenital dislocated hips and elderly depression. She underwent a valve replacement 2 years prior due to mitral insufficiency and had been taking 1?mg of warfarin and 100?mg of aspirin daily. There was no appreciable family history. She experienced enlargement and severe pain in the left buttock on April 26 without an obvious etiology such as trauma. The severe pain led to self-injury, and she was transported to an emergency hospital in hemorrhagic shock. She was diagnosed with elderly depression and was transferred to a psychiatric hospital on May 7th. Her laboratory tests showed that she had severe anemia (Hgb 5.1?g/dL). Thus, she was transferred to Hospital A on June 8th and underwent systemic examinations for anemia, including colonofiberscopy. However, a bleeding source such as
Preparation and Properties of Polyaniline in the Presence of Trehalose  [PDF]
Hirotsugu Kawashima, Hiromasa Goto
Soft Nanoscience Letters (SNL) , 2011, DOI: 10.4236/snl.2011.13013
Abstract: Oxidative polymerization of aniline in aqueous solution in the presence of trehalose was conducted. Fourier transform infrared spectroscopy confirmed successful preparation of polyaniline containing a trace amount of trehalose. Electron spin resonance spectroscopy revealed that electron spin concentration of the polyaniline increases with aniline/trehalose ratio in the polymerization. Scanning electron microscopy revealed that the polyaniline shows granular and porous morphology. Electrical conductivity of these polyanilines was in the order of 10-4 S/cm.
Novel Cathode Materials for Sodium Ion Batteries Derived from Layer Structured Titanate Cs2Ti5O11·(1 + x)H2O  [PDF]
Masao Ohashi
Materials Sciences and Applications (MSA) , 2018, DOI: 10.4236/msa.2018.96037
Abstract: A layer structured titanate Cs2Ti5O11·(1 + x)H2O (x = 0.70) has been prepared in a solid state reaction using Cs2CO3 and anatase type TiO2 at 900°C. Ion exchange reactions of Cs+ in the interlayer space were studied in aqueous solutions. The single phases of Li+, Na+ and H+ exchange products were obtained. The three kinds of resulting titanates were evaluated for use as the cathodes in rechargeable sodium batteries after dehydrations by heating at 200°C in a vacuum. The electrochemical measurements showed that they exhibited the reversible Na+ intercalation-deintercalation in a voltage range of 0.5 - 3.5 V or 0.7 - 4.0 V. The Li+ exchange product showed the best performance of the discharge-charge capacities in this study. The initial Na+ intercalation-deintercalation capacities of the Li2Ti5O11 were 120 mAh/g and 100 mAh/g; the amounts of Na+ correspond to 1.9 and 1.6 of the formula unit, respectively. The titanates are nontoxic, inexpensive and environmentally benign.
Ion Exchange of Layer-Structured Titanate CsxTi2-x/2Mgx/2O4 (x = 0.70) and Applications as Cathode Materials for Both Lithium- and Sodium-Ion Batteries  [PDF]
Masao Ohashi
Materials Sciences and Applications (MSA) , 2019, DOI: 10.4236/msa.2019.102012
Abstract: Cathode materials for rechargeable batteries have been extensively investigated. Sodium-ion batteries are emerging as alternatives to lithium-ion batteries. In this study, a novel cathode material for both lithium- and sodium-ion batteries has been derived from a layered crystal. Layer-structured titanate CsxTi2-x/2Mgx/2O4 (x = 0.70) with lepidocrocite (γ-FeOOH)-type structure has been prepared in a solid-state reaction from Cs2CO3, anatase-type TiO2, and MgO at 800°C. Ion-exchange reactions of Cs+ in the interlayer space were studied in aqueous solutions. The single phases of Li+, Na+, and H+ exchange products were obtained, and these were found to contain interlayer water. The interlayer water in the lithium ion-exchange product was removed by heating at 180°C in vacuum. The resulting titanate Li0.53H0.13Cs0.14Ti1.65Mg0.30O4 was evaluated for use as cathodes in both rechargeable lithium and sodium batteries. The Li+ intercalation-deintercalation capacities were found to be 151 mAh/g and 114 mAh/g, respectively, for the first cycle in the voltage range 1.0 - 3.5 V. The amounts of Li+ corresponded to 0.98 and 0.74 of the formula unit, respectively. The Na+ intercalation-deintercalation capacities were 91 mAh/g and 77 mAh/g, respectively, for the first cycle in the voltage range 0.70 - 3.5 V. The amounts of Na+ corresponded to 0.59 and 0.50 of the formula unit, respectively. The new cathode material derived from the layer-structured titanate is non-toxic, inexpensive, and environmentally benign.
Synthesis and Properties of a Chiroptically Active Oligomer from 3,4-Ethylenedioxythiophene and (–)-Myrtenal
Hirotsugu Kawashima,Hiromasa Goto
Materials , 2011, DOI: 10.3390/ma4061013
Abstract: Oxidative polycondensation of 3,4-ethylenedioxythiophene and (–)-myrtenal was carried out with POCl 3. A p-conjugated system thus constructed consists of aromatic and quinoidal alternating structure linked via methine groups. We examined iodine doping effect for the resultant material with electron spin resonance spectroscopy. Circular dichroism spectra in chloroform solution showed blue-shift with increase of iodine concentration. This result indicates that the doping process can tune chiroptical activity of the chiral π-conjugated system.
Heavy quark pair production in high energy pA collisions: Quarkonium
Fujii, Hirotsugu;Watanabe, Kazuhiro
High Energy Physics - Phenomenology , 2013,
Abstract: Quarkonium production in high-energy proton (deuteron)-nucleus collisions is investigated in the color glass condensate framework. We employ the color evaporation model assuming that the quark pair produced from dense small-x gluons in the nuclear target bounds into a quarkonium outside the target. The unintegrated gluon distribution at small Bjorken x in the nuclear target is treated with the Balitsky-Kovchegov equation with running coupling corrections. For the gluons in the proton, we examine two possible descriptions, unintegrated gluon distribution and ordinary collinear gluon distribution. We present the transverse momentum spectrum and nuclear modification factor for J/psi production at RHIC and LHC energies, and those for Upsilon(1S) at LHC energy, and discuss the nuclear modification factor and the momentum broadening by changing the rapidity and the initial saturation scale.
Leptons from heavy-quark semileptonic decay in pA collisions within the CGC framework
Hirotsugu Fujii,Kazuhiro Watanabe
Physics , 2015,
Abstract: We study single lepton production from semileptonic decays of heavy flavor hadrons ($D,B\rightarrow~l$) in pp and p$A$ collisions at RHIC and the LHC within the saturation/Color-Glass-Condensate (CGC) framework. Using the gluon distribution function obtained with the dipole amplitude, whose energy dependence is described by the Balitsky-Kovchegov equation with running coupling effect, we compute the transverse-momentum ($p_\perp$) spectra of the lepton yields at mid and forward rapidities. We find that a large fraction of leptons at low $p_\perp$ stems from the saturation regime of the incoming gluons in the target, especially in p$A$ collisions at the LHC. The resultant $p_\perp$ spectra is slightly harder than the data, but the nuclear modification factor seems consistent with the data within some uncertainty. We also update the nuclear modification factors for J/$\psi$ and $D$ meson at the LHC energy.
Heavy quark pair production in high energy pA collisions: Quarkonium
Hirotsugu Fujii,Kazuhiro Watanabe
Physics , 2013, DOI: 10.1016/j.nuclphysa.2013.06.011
Abstract: Quarkonium production in high-energy proton (deuteron)-nucleus collisions is investigated in the color glass condensate framework. We employ the color evaporation model assuming that the quark pair produced from dense small-x gluons in the nuclear target bounds into a quarkonium outside the target. The unintegrated gluon distribution at small Bjorken x in the nuclear target is treated with the Balitsky-Kovchegov equation with running coupling corrections. For the gluons in the proton, we examine two possible descriptions, unintegrated gluon distribution and ordinary collinear gluon distribution. We present the transverse momentum spectrum and nuclear modification factor for J/psi production at RHIC and LHC energies, and those for Upsilon(1S) at LHC energy, and discuss the nuclear modification factor and the momentum broadening by changing the rapidity and the initial saturation scale.
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