248 results on '"Tetsuya Tatsumi"'
Search Results
152. [Therapeutic angiogenesis for peripheral arterial disease and ischemic heart disease by autologous bone marrow cells implantation]
- Author
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Tetsuya, Tatsumi and Hiroaki, Matsubara
- Subjects
Male ,Peripheral Vascular Diseases ,Leg ,Myocardial Ischemia ,Endothelial Cells ,Humans ,Neovascularization, Physiologic ,Middle Aged ,Regenerative Medicine ,Transplantation, Autologous ,Bone Marrow Transplantation ,Forecasting ,Randomized Controlled Trials as Topic - Abstract
Postnatal neovascularization was initially thought to result exclusively from the migration and proliferation of pre-existing, fully differentiated endothelial cells (a process referred to as angiogenesis). Several lines of experimental evidence, however, demonstrated that circulating endothelial progenitor cells (EPCs) home to sites of neovascularization and differentiate into endothelial cells in situ in a manner consistent with a process termed vasculogenesis. Moreover, recent clinical study, named as the Therapeutic Angiogenesis Using Cell Transplantation (TACT), has demonstrated the efficacy and safety of autologous implantation of bone marrow-mononuclear cells(BM-MNCs) in randomly allocated patients with ischemic limbs of peripheral arterial diseases. Implantation of BM-MNCs is also applied to patients with no-option angina pectoris, demonstrating the usefulness of this therapy for improvement of symptom, myocardial perfusion, and exercise capacity. Moreover, recent accumulating studies demonstrated the possibilities that transplantation of bone marrow-derived or peripheral blood-derived EPCs enhances neovascularization and improves cardiac function after acute myocardial infarction(AMI). There were no serious adverse effects reported in cell transplantation therapy. Thus, bone marrow-derived cell transplantation therapy has been applied to acute and chronic ischemic heart diseases as well as peripheral arterial diseases, demonstrating the safety and effectiveness of therapeutic angiogenesis.
- Published
- 2006
153. HMG-CoA reductase inhibition improves anti-aging klotho protein expression and arteriosclerosis in rats with chronic inhibition of nitric oxide synthesis
- Author
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Tsuguru Hatta, Kazuo Takeda, Hidekazu Irie, Tetsuya Tatsumi, Miyuki Kobara, Susumu Sasaki, Hiromichi Narumiya, Shinji Hushiki, Tetsuo Nakata, Hiroaki Matsubara, and Noriko Kuwahara
- Subjects
Male ,medicine.medical_specialty ,Arteriosclerosis ,Atorvastatin ,urologic and male genital diseases ,Internal medicine ,medicine ,Animals ,Pyrroles ,Rats, Wistar ,Pitavastatin ,Klotho ,Klotho Proteins ,Glucuronidase ,Kidney ,biology ,business.industry ,Anticholesteremic Agents ,medicine.disease ,Blockade ,Rats ,Nitric oxide synthase ,medicine.anatomical_structure ,Endocrinology ,Heptanoic Acids ,HMG-CoA reductase ,biology.protein ,Quinolines ,Hydroxymethylglutaryl-CoA Reductase Inhibitors ,Nitric Oxide Synthase ,Cardiology and Cardiovascular Medicine ,business ,medicine.drug - Abstract
Background The klotho gene and its protein product are mainly expressed in the kidney. The klotho protein induces suppression of multiple aging-related phenotypes, and homozygous klotho gene mutant mice display various senescent morbidity. Chronic inhibition of nitric oxide synthase (NOS) induces arteriosclerosis, while HMG-CoA reductase inhibitors (statins) have pleiotropic vascular protective effects besides cholesterol lowering. Therefore, the present studies were performed to determine whether chronic NOS blockade would affect anti-ageing klotho protein expression. In addition, the effects of statins on klotho protein expression and arteriosclerosis in these rats were investigated. Methods Forty-two rats were divided into 6 groups as follows: (1) control, (2) NOS blockade, (3) atorvastatin (10 mg/kg/day), (4) pitavastatin (3 mg/kg/day), (5) NOS blockade+atorvastatin, (6) NOS blockade+pitavastatin. To induce arteriosclerosis further, a cuff was placed around the left femoral artery in each rat. After 4 weeks observation, rats were killed and renal klotho expression and the level of arteriosclerosis were examined. Results The rats of chronic NOS inhibition developed hypertension, while statin treatment did not affect blood pressure in the rats with or without NOS blockade. Despite statin treatment, plasma levels of lipids did not differ among 6 groups. Immunohistochemical staining revealed that klotho protein was localized in the renal tubules. Chronic NOS inhibition markedly reduced renal klotho protein expression, while treatment with atorvastatin or pitavastatin completely prevented the reduction of klotho expression induced by NOS inhibition. In addition, statin treatment significantly improved arteriosclerotic lesions induced by NOS inhibition and cuff placement. Conclusion Since statin treatment did not alter blood pressure or serum lipid profiles, a novel vascular protective effect of statins via enhancing anti-aging klotho protein expression is suggested.
- Published
- 2006
154. [Cardioprotective effect of aldosterone antagonists for ventricular remodeling]
- Author
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Tetsuya, Tatsumi and Hiroaki, Matsubara
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Heart Failure ,Clinical Trials as Topic ,Receptors, Mineralocorticoid ,Ventricular Remodeling ,Animals ,Humans ,Spironolactone ,Reactive Oxygen Species ,Aldosterone ,Eplerenone ,Mineralocorticoid Receptor Antagonists - Published
- 2006
155. Erythropoietin-mobilized endothelial progenitors enhance reendothelialization via Akt-endothelial nitric oxide synthase activation and prevent neointimal hyperplasia
- Author
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Tetsuya Nomura, Hiroyuki Yamada, Yasushi Aadachi, Hiroaki Matsubara, Tetsuya Tatsumi, Mitsuhiko Okigaki, Tomosaburo Takahashi, Shinsaku Matsunaga, Kuniharu Matsuno, Norifumi Urao, Akihiro Matsui, and Kento Tateishi
- Subjects
Male ,medicine.medical_specialty ,Endothelium ,Nitric Oxide Synthase Type III ,Physiology ,Apoptosis ,Bone Marrow Cells ,Nitric Oxide ,Mice ,Downregulation and upregulation ,Cell Movement ,Internal medicine ,Receptors, Erythropoietin ,Medicine ,Animals ,Humans ,Progenitor cell ,Protein kinase B ,Erythropoietin ,Cells, Cultured ,Bone Marrow Transplantation ,Neointimal hyperplasia ,Wound Healing ,Hyperplasia ,biology ,business.industry ,medicine.disease ,Recombinant Proteins ,Nitric oxide synthase ,Enzyme Activation ,Femoral Artery ,Mice, Inbred C57BL ,Endocrinology ,medicine.anatomical_structure ,Immunology ,cardiovascular system ,biology.protein ,Wounds and Injuries ,Bone marrow ,Endothelium, Vascular ,Cardiology and Cardiovascular Medicine ,business ,Tunica Intima ,Proto-Oncogene Proteins c-akt ,medicine.drug - Abstract
We investigated whether the mobilization of endothelial progenitor cells (EPCs) by exogenous erythropoietin (Epo) promotes the repair of injured endothelium. Recombinant human Epo was injected (1000 IU/kg for the initial 3 days) after wire injury of the femoral artery of mice. Neointimal formation was inhibited by Epo to 48% of the control ( P + /Flk-1 + EPCs (2.0-fold, P P
- Published
- 2006
156. Medium-term prognosis of young Japanese adults having acute myocardial infarction
- Author
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Jun Shiraishi, Yoshio Kohno, Shinichiro Yamaguchi, Masayasu Arihara, Mitsuyoshi Hadase, Masayuki Hyogo, Takakazu Yagi, Takatomo Shima, Takahisa Sawada, Tetsuya Tatsumi, Akihiro Azuma, Hiroaki Matsubara, and null The AMI-Kyoto Multi-Center Risk Study Group
- Subjects
Adult ,Male ,medicine.medical_specialty ,medicine.medical_treatment ,Myocardial Infarction ,Japan ,Recurrence ,Risk Factors ,Internal medicine ,medicine ,Humans ,cardiovascular diseases ,Myocardial infarction ,Young adult ,Aged ,Retrospective Studies ,biology ,business.industry ,Incidence (epidemiology) ,Age Factors ,Percutaneous coronary intervention ,General Medicine ,Thrombolysis ,Middle Aged ,medicine.disease ,Prognosis ,Survival Rate ,biology.protein ,Cardiology ,Blood Vessels ,Creatine kinase ,Cardiology and Cardiovascular Medicine ,business ,Body mass index ,Mace - Abstract
Background Data on the medium- and long-term prognosis of young Japanese patients with acute myocardial infarction (AMI) are still lacking. Methods and Results In the present study, 1,458 AMI patients were enrolled in the AMI-Kyoto Multi-Center Risk Study between January 2000 and December 2003. Of these, clinical characteristics and medium-term prognosis were retrospectively compared in 21 young patients
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- 2006
157. Changes of chemical nature of photoresists induced by various plasma treatments and their impact on LWR
- Author
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Makiko Irie, Nobuyuki Matsuzawa, Hiroichi Kawahira, Tetsuya Tatsumi, K. M. A. Salam, Takeshi Iwai, Hiroyuki Nakano, Yuko Yamaguchi, Eriko Matsui, K. Kugimiya, Masashi Yoshida, and Atsuhiro Ando
- Subjects
Materials science ,Softening point ,Etching (microfabrication) ,law ,Analytical chemistry ,Thermomechanical analysis ,Capacitively coupled plasma ,Inductively coupled plasma ,Photoresist ,Photolithography ,Softening ,law.invention - Abstract
Changes in chemical nature of an ArF photoresist caused by various plasmas were analyzed, and it was found that the HBr plasma treatment induces a selective detachment of a heterocyclic unit of the photoresist, and the detached unit remains in the photoresist film. Thermomechanical analyses were performed, which showed that the softening temperature of the photoresist decreases by the HBr treatment, indicating that the detached heterocyclic unit acts as a plasticizer in the photoresist film. These results showed that the HBr treatment can be regarded as a softening process of the photoresist. This HBr treatment was applied to the fabrication of line patterns and it was shown that the treatment remarkably improves LWR (line width roughness) after etching. This improvement was more pronounced for the case of an isolated pattern than the case of a dense pattern. Further investigations on the HBr treatment were performed by changing the copolymerization ratio of a monomer containing the heterocyclic unit. It was shown that the reduction of LWR by the HBr treatment becomes more enhanced when the copolymerization ratio increases. However, an intensive HBr treatment was found to deteriorate LWR, showing that there is an optimum condition of the HBr treatment in terms of improving LWR.
- Published
- 2006
158. Granulocyte colony-stimulating factor-mobilized circulating c-Kit+/Flk-1+ progenitor cells regenerate endothelium and inhibit neointimal hyperplasia after vascular injury
- Author
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Yoshihisa Nozawa, Tetsuya Tatsumi, Mitsuhiko Okigaki, Tomosaburo Takahashi, Mizuo Miyazaki, Yasushi Adachi, Eishi Ashihara, Michitaka Takamiya, Tetsuya Nomura, Kento Tateishi, Denan Jin, Hiroaki Matsubara, Shinji Takai, Kan Zen, and Norifumi Urao
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medicine.medical_specialty ,Endothelium ,Nitric Oxide Synthase Type III ,Carotid Artery, Common ,Injections, Subcutaneous ,chemistry.chemical_compound ,Mice ,Internal medicine ,Granulocyte Colony-Stimulating Factor ,medicine ,Animals ,Humans ,Regeneration ,Progenitor cell ,Cells, Cultured ,Evans Blue ,Cell Proliferation ,Neointimal hyperplasia ,Hyperplasia ,business.industry ,Stem Cells ,medicine.disease ,Extravasation ,Recombinant Proteins ,Granulocyte colony-stimulating factor ,Rats ,Vasodilation ,Proto-Oncogene Proteins c-kit ,medicine.anatomical_structure ,Endocrinology ,chemistry ,Rats, Inbred Lew ,Immunology ,Bone marrow ,Endothelium, Vascular ,Cardiology and Cardiovascular Medicine ,business ,Carotid Artery Injuries ,Tunica Intima ,Blood vessel - Abstract
Background— Granulocyte colony-stimulating factor (G-CSF) treatment was shown to inhibit neointimal formation of balloon-injured vessels, whereas neither the identification of progenitor cells involved in G-CSF–mediated endothelial regeneration with a bone marrow (BM) transplant experiment nor the functional properties of regenerated endothelium have been studied. Methods and Results— Recombinant human G-CSF (100 μg/kg per day) was injected daily for 14 days starting 3 days before balloon injury in the rat carotid artery. Neointimal formation of denuded vessels on day 14 was markedly attenuated by G-CSF (39% versus the control; P P P =0.02). The regenerated endothelium exhibited acetylcholine-mediated vasodilatation in NO-dependent manner. G-CSF increased the circulating c-Kit+/Flk-1+ cells (9.1-fold; P Conclusion— The G-CSF–induced mobilization of BM-derived c-Kit+/Flk-1+ cells contributes to endothelial regeneration, and this cytokine therapy may be a feasible strategy for the promotion of re-endothelialization after angioplasty.
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- 2006
159. Myocardium-targeted delivery of endothelial progenitor cells by ultrasound-mediated microbubble destruction improves cardiac function via an angiogenic response
- Author
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Yasushi Adachi, Kan Zen, Yoshihisa Nozawa, Michitaka Takamiya, Norifumi Urao, Yohei Hosokawa, Hiroaki Matsubara, Tetsuya Tatsumi, Mitsuhiko Okigaki, Kento Tateishi, and Tomosaburo Takahashi
- Subjects
Cardiac function curve ,medicine.medical_specialty ,Cardiac fibrosis ,Cell Transplantation ,Neovascularization, Physiologic ,Bone Marrow Cells ,Internal medicine ,Cricetinae ,medicine ,Animals ,Cell Lineage ,Ultrasonics ,RNA, Messenger ,Progenitor cell ,Ventricular remodeling ,Molecular Biology ,Microbubbles ,Ventricular Remodeling ,Chemistry ,Myocardium ,Stem Cells ,Body Weight ,Skeletal muscle ,Endothelial Cells ,Heart ,Anatomy ,Organ Size ,medicine.disease ,Coronary Vessels ,Endocrinology ,medicine.anatomical_structure ,Echocardiography ,Heart failure ,Cytokines ,Angiogenesis Inducing Agents ,Cardiology and Cardiovascular Medicine ,Perfusion ,Cell Adhesion Molecules - Abstract
Application of ultrasound-mediated destruction of microbubbles (US + Bubble) to skeletal muscle creates capillary ruptures leading to leakage of the cell components. We studied whether US + Bubble combined with bone-marrow-derived mononuclear cells (BM-MNCs) infusion enables the targeted delivery of endothelial-lineage cells into the myocardium and improves cardiac function of the cardiomyopathy model due to the paucity of neocapillary formation. Pulsed US was applied to the anterior chest of BIOTO2 cardiomyopathy hamsters for 90 s after the intravenous injection of microbubble (Optison) followed by infusion of BM-MNCs. Cardiac samples from US + microbubble + BM-MNCs (US + Bubble + BM), US + Bubble, US + BM without Bubble, and saline infusion control groups were analyzed 12 weeks after treatment. Labeled BM-MNCs transplanted by US + Bubble were found to be mainly localized in the microvessels, but not by US stimulation without microbubble (121.2 +/- 24.5 vs. 2.80 +/- 1.30 cells/mm2, P < 0.001). Capillary densities in US + Bubble + BM group were increased 1.7-fold (P < 0.05) over the control, and neither US + Bubble nor US + BM enhanced neocapillary formation. 99mTc-Tetrofosmin scintigraphy revealed that blood perfusion area in the US + Bubble + BM group was 48% greater than the control (P < 0.01). US + Bubble stimulation induces the expression of adhesion molecules (VCAM-1 and ICAM-1) in capillaries, and the US + Bubble-mediated supply of BM-MNCs increased the myocardial content of VEGF and bFGF. The left ventricular wt/body wt, area of cardiac fibrosis, and apoptotic cell numbers in the US + Bubble + BM group significantly (P < 0.05) decreased by 82%, 73%, and 64% relative to the control, respectively. The cardiac function in myopathic hamsters (assessed by fractional shortening) was markedly improved 36% (P < 0.05) by US + Bubble + BM treatment. Targeted delivery of BM-MNCs by US + Bubble to the myocardium of the cardiomyopathic hamster increased the capillary densities and regional blood flow and inhibited cardiac remodeling, resulting in the prevention of heart failure. This non-invasive cell delivery system may be useful as a novel efficient approach for angiogenic cell therapy to the myocardium.
- Published
- 2006
160. Influence of hydrogen in silicon nitride films on the surface reactions during hydrofluorocarbon plasma etching.
- Author
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Nobuyuki Kuboi, Tetsuya Tatsumi, Hideki Minari, Masanaga Fukasawa, Yoshifumi Zaizen, Jun Komachi, and Takahiro Kawamura
- Subjects
PLASMA etching ,SILICON nitride films ,HYDROGEN ,PLASMA-enhanced chemical vapor deposition ,MOLECULAR dynamics - Abstract
The influence of the amount of hydrogen (H) in hydrogenated silicon nitride films (Si
x Ny :Hz ) on the etching properties and etching mechanism are unclear for hydrofluorocarbon plasma etching. Therefore, the authors have investigated the effect of H in Six Ny :Hz films on the surface reactions during CH2 F2 /Ar/O2 plasma etching by experimental and numerical simulation techniques. The experimental etch yield (EY) and polymer layer thickness (TC-F ) values for Six Ny :Hz films with different H concentrations of 2.6% (low-SiN), 16.8% (mod-SiN), and 21.9% (high-SiN) show different trends with the CH2 F2 /(CH2 F2 + O2 ) flow rate ratio. To understand the mechanism of the different etching properties, the authors estimated the chemical reaction probabilities of the H outflux between F, O, N, C, and Si dangling bonds using first principles calculations and the results of Fourier transform infrared spectroscopy. Based on the estimated reaction probabilities, the authors modeled the surface reactions of Six Ny :Hz films under the assumption that the H outflux mainly scavenges incident F radicals (the main etchant species). The authors also consider that the reaction between H and N from outfluxes decreases the desorption reactions of C2 N2 and HCN, resulting in a larger TC-F value. Comparing the simulation results of the trends in the whole flow rate ratio range and the absolute values of EY and TC-F with experimental data, the surface model can successfully explain the mechanism. Furthermore, the authors demonstrated time-dependent etched profile and damage distribution for fin-type field-effect transistor Six Ny :Hz side-wall etching using the three-dimensional voxel-slab model with the above surface reactions to obtain knowledge about the effect of H on the etched profile and damage distribution. The results show that the etched profile and damage distribution on the Si fin structure are very different for low-SiN and high-SiN because of the different EY and TC-F values induced by different H outfluxes. These results indicate that it is important to carefully control both the etching process and amount of H in the Six Ny :Hz film to achieve high-performance advanced complementary metal oxide semiconductor devices. [ABSTRACT FROM AUTHOR]- Published
- 2017
- Full Text
- View/download PDF
161. Effects of hydrogen ion irradiation on zinc oxide etching.
- Author
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Hu Li, Kazuhiro Karahashi, Friederich, Pascal, Fink, Karin, Masanaga Fukasawa, Akiko Hirata, Kazunori Nagahata, Tetsuya Tatsumi, Wolfgang Wenzel, and Satoshi Hamaguchi
- Subjects
HYDROGEN ions ,ZINC oxide ,HYDROCARBONS ,ETCHING ,ION beams ,DENSITY functional theory - Abstract
Mechanisms of zinc oxide (ZnO) etching by hydrocarbon plasmas were investigated both experimentally and theoretically with the use of a mass-selected ion beam system and firstprinciple quantum mechanical (QM) simulation based on the density functional theory. The massselected ion beam experiments have shown that the sputtering yield of ZnO increases by a pretreatment of the ZnO film by energetic hydrogen (H) ion injections prior to heavy ion bombardment, suggesting that chemically enhanced etching of ZnO by hydrocarbon plasmas is closely related to hydrogen storage and/or formation of damage in the ZnO layer by energetic hydrogen injections. In this study, the effects of hydrogen storage in ZnO are examined. First-principle QM simulation of ZnO interacting with H atoms has shown that H atoms in ZnO form hydroxyl (OH) groups (or partially convert ZnO to ZnOH), which results in the weakening or breaking of the Zn-O bonds around H atoms and thus makes the ZnO film more prone to physical sputtering. The formation of hydroxyl groups in ZnO is also expected to occur in ZnO etching by hydrocarbon plasmas and increase its sputtering yields over those by inert-gas plasmas generated under similar conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
162. Nicorandil regulates Bcl-2 family proteins and protects cardiac myocytes against hypoxia-induced apoptosis
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Jun Shiraishi, Mitsuo Takeda, Shinsaku Matsunaga, Susumu Nishikawa, Miyuki Kobara, Tetsuya Tatsumi, Akiko Mano, Mitsuhiko Okigaki, Tomosaburo Takahashi, Natsuya Keira, and Hiroaki Matsubara
- Subjects
medicine.medical_specialty ,Indoles ,Vasodilator Agents ,Carbazoles ,Apoptosis ,Mitochondrion ,Biology ,Nitric Oxide ,Internal medicine ,medicine ,Myocyte ,Animals ,Myocytes, Cardiac ,Nicorandil ,Molecular Biology ,Cation Transport Proteins ,Cyclic GMP ,Protein Kinase Inhibitors ,Cells, Cultured ,Cardioprotection ,Dose-Response Relationship, Drug ,Cytochrome c ,Myocardium ,Bcl-2 family ,Cell Hypoxia ,Mitochondria ,Rats ,Endocrinology ,Animals, Newborn ,Proto-Oncogene Proteins c-bcl-2 ,cardiovascular system ,biology.protein ,Cardiology and Cardiovascular Medicine ,cGMP-dependent protein kinase ,medicine.drug ,Signal Transduction - Abstract
Nicorandil has been shown to inhibit myocyte apoptosis by opening of mitochondrial ATP-sensitive potassium (mitoK(ATP)) channels and nitrate-like effect against oxidative stress. However, the detailed mechanism of nicorandil-mediated cardioprotection under hypoxic conditions remains to be largely unknown. The present study examined whether nicorandil can inhibit apoptosis via regulation of Bcl-2 family proteins in hypoxic myocytes. Neonatal rat cardiac myocytes were exposed to hypoxia for 7 hours. Hypoxia-induced myocyte apoptosis (13.9+/-0.9%) under glucose-rich conditions. Myocyte apoptosis was accompanied by loss of mitochondrial membrane potential (Deltapsi(m)), cytochrome c release from mitochondria into cytosol, and activation of caspase-3. Hypoxia also significantly increased Bax and decreased Bcl-2 mRNA and protein expression, thereby increasing Bax/Bcl-2 ratio. Nicorandil 100 micromol/l significantly decreased the percentage of apoptotic myocytes (7.2+/-0.5%) by inhibiting loss of Deltapsi(m) and translocation of cytochrome c. These effects of nicorandil were partially but significantly inhibited by cotreatment of either 500 micromol/l 5-hydroxydecanoate, a selective mitoK(ATP) channel antagonist, or 10 micromol/l 1H-[1,2,4]oxidazolo[4,3-a]quinoxalin-1-one (ODQ), an inhibitor of soluble guanylate cyclase. Moreover, nicorandil significantly inhibited the hypoxia-induced changes in Bax and Bcl-2 expression, and concomitant increased Bax and decreased Bcl-2 immunoreactivity in mitochondria. These effects of nicorandil in Bax and Bcl-2 expression were significantly blunted by cotreatment of ODQ and 5-HD, respectively. Cotreatment of KT5823, an inhibitor of protein kinase G, significantly blocked the effect of nicorandil on Bax expression and 8-bromo-cyclic guanosine 3',5' monophosphate (8-bromo-cGMP), a cGMP analog, mimicked the effect of nicorandil on Bax expression. The present study demonstrates that nicorandil regulates Bcl-2 family proteins via opening of mitoK(ATP) channels and nitric oxide-cGMP signaling and inhibits hypoxia-induced mitochondrial death pathway.
- Published
- 2005
163. Guide Catheter Extension Device Is Effective in Renal Angioplasty for Severely Calcified Lesions.
- Author
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Takeshi Sugimoto, Tetsuya Nomura, Yusuke Hori, Kenichi Yoshioka, Hiroshi Kubota, Daisuke Miyawaki, Ryota Urata, Masakazu Kikai, Natsuya Keira, and Tetsuya Tatsumi
- Subjects
CATHETERS ,ANGIOPLASTY ,TISSUE wounds ,ENDOVASCULAR surgery ,RENAL artery - Abstract
Objective: Unusual setting of medical care Background: The GuideLiner catheter extension device is a monorail-type "Child" support catheter that facilitates coaxial alignment with the guide catheter and provides an appropriate back-up force. This device has been developed in the field of coronary intervention, and now is becoming widely applied in the field of endovascular treatment. However, there has been no report on the effectiveness of the guide catheter extension device in percutaneous transluminal renal angioplasty (PTRA). Case Report: We encountered a case of atherosclerotic subtotal occlusion at the ostium of the left renal artery. Due to the severely calcified orifice and weaker back-up force provided by a JR4 guide catheter, we could not pass any guidewires through the target lesion. Therefore, we introduced a guide catheter extension device, the GuideLiner catheter, through the guide catheter and achieved good guidewire maneuverability. We finally deployed 2 balloon-expandable stents and successfully performed all PTRA procedures. Conclusions: The guide catheter extension device can be effective in PTRA for severely calcified subtotal occlusion. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
164. Interventional treatment for very young adults with acute myocardial infarction. Clinical manifestations and outcome
- Author
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Jun, Shiraishi, Hirokazu, Shiraishi, Hironori, Hayashi, Takahisa, Sawada, Tetsuya, Tatsumi, Akihiro, Azuma, and Hiroaki, Matsubara
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Adult ,Male ,Cardiac Catheterization ,Time Factors ,Myocardial Infarction ,Humans ,Angioplasty, Balloon, Coronary ,Coronary Angiography ,Follow-Up Studies - Abstract
Direct percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) is now established as a standard therapy for older patients. However, experience with PCI in very young adults with AMI has been limited. In this report we retrospectively evaluated the effectiveness of PCI for very young adults with AMI and estimated their clinical characteristics and outcome. Of the 502 patients with AMI, 5 were 35 years old or younger (1.0%) during a period of 4 years (2000--2004). We assessed the utility of PCI in these five consecutive patients under the age of 35 presenting with a first AMI. Five AMI patients, ranging in age from 20 to 34 years (median, 27+/-5 years) underwent direct PCI for the culprit lesions. The lesions targeted for PCI were located in the left anterior descending artery in 3 patients and in the right coronary artery in 2 patients. One patient had a past history of Kawasaki disease (KD). In all of the patients, PCI were angiographically effective at the acute phase without complication. In hospital course, a subacute stent thrombosis occurred in one patient. Follow-up angiograms performed 6 months after the procedure revealed no restenosis, but identified a new coronary aneurysm in one patient with a past history of KD and a regressed giant coronary aneurysm probably due to atypical KD in another patient, which were confirmed by intravascular ultrasound. There was one death ascribed to heart failure 8 months after the initial PCI. The findings of this report suggest that PCI for very young adults with AMI can be safe and effective in the short-term.
- Published
- 2005
165. Beneficial effect of cibenzoline on left ventricular pressure gradient with sigmoid septum
- Author
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Miho Inoue, Jun Shiraishi, Chika Konishi, Hiroaki Matsubara, Akihiro Azuma, Tetsuya Tatsumi, Naoko Muraguchi, and Katsuichi Ohtsuki
- Subjects
medicine.medical_specialty ,Heart Ventricles ,Ventricular outflow tract obstruction ,Blood Pressure ,Left ventricular hypertrophy ,chemistry.chemical_compound ,Mitral valve ,Internal medicine ,Heart Septum ,Medicine ,Humans ,cardiovascular diseases ,Interventricular septum ,Metoprolol ,Aged ,Aged, 80 and over ,Heart Murmurs ,business.industry ,Imidazoles ,General Medicine ,Cardiomyopathy, Hypertrophic ,medicine.disease ,medicine.anatomical_structure ,Dyspnea ,chemistry ,Ventricle ,Echocardiography ,Anesthesia ,Cibenzoline ,Hypertension ,cardiovascular system ,Ventricular pressure ,Cardiology ,Female ,medicine.symptom ,Cardiology and Cardiovascular Medicine ,business ,Anti-Arrhythmia Agents ,medicine.drug - Abstract
An 83-year-old woman with hypertension was admitted to hospital with episodes of dyspnea on effort after having breakfast. Physical examination revealed a systolic murmur at the left sternal border in the third to fourth intercostal space. Cross-sectional echocardiography showed a sigmoid-shaped interventricular septum markedly protruding into the left ventricle, concentric left ventricular hypertrophy, systolic anterior motion of the mitral valve, and a resultant left ventricular outflow tract obstruction with a pressure gradient of 121.8 mmHg. She began daily treatment with 60 mg metoprolol. However, the chest symptoms were not relieved and the left ventricular outflow tract obstruction was still visible on echocardiography. She was then given 200 mg daily of cibenzoline, in addition to 40 mg metoprolol, and the left ventricular pressure gradient significantly decreased and she was free of symptoms without any complications. This case shows that cibenzoline may be useful in the treatment of left ventricular outflow tract obstruction caused by sigmoid septum. (Circ J 2004; 68: 968 - 971)
- Published
- 2004
166. Cytokine-induced nitric oxide inhibits mitochondrial energy production and induces myocardial dysfunction in endotoxin-treated rat hearts
- Author
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Satoaki Matoba, Nobuhiro Hibino, Miyuki Kobara, Hiroaki Matsubara, Akiko Mano, Jun Asayama, Natsuya Keira, Jun Shiraishi, Kazuko Akashi, Masao Nakagawa, Henry Fliss, Satoru Hosokawa, Shinji Fushiki, Tetsuya Tatsumi, and Satoshi Yamanaka
- Subjects
Adenosine monophosphate ,Lipopolysaccharides ,Male ,medicine.medical_specialty ,ATPase ,Nitric Oxide Synthase Type II ,Blood Pressure ,Mitochondrion ,In Vitro Techniques ,Creatine ,Nitric Oxide ,Mitochondria, Heart ,Nitric oxide ,Rats, Sprague-Dawley ,chemistry.chemical_compound ,Adenosine Triphosphate ,Internal medicine ,medicine ,Citrate synthase ,Animals ,Molecular Biology ,Heart metabolism ,biology ,Myocardium ,Adenosine ,Rats ,Adenosine Diphosphate ,Endocrinology ,chemistry ,biology.protein ,Cytokines ,Nitric Oxide Synthase ,Cardiology and Cardiovascular Medicine ,Cardiomyopathies ,Energy Metabolism ,medicine.drug - Abstract
The mechanism responsible for cardiac depression in septic shock remains unknown. The present study examined whether nitric oxide (NO) overproduced by inducible NO synthase (iNOS) can inhibit aerobic energy metabolism and impair the myocardial function in endotoxin-treated rat hearts. Lipopolysaccharide (LPS) significantly decreased systolic blood pressure (BP) to 44% of control during the 48 h treatment. Hearts from control and LPS-treated rats were perfused in a Langendorff apparatus. After LPS injection, left ventricular (LV) developed pressure (LVDP) was significantly depressed, plasma NO2-/NO3- (NO(x)) concentration was markedly increased, and myocardial adenosine 5'-triphosphate (ATP), creatine phosphate (CrP), and the ratio of ATP/adenosine 5'-diphosphate were progressively decreased with time. Immunological examination showed a significant expression of iNOS protein in the LPS-treated myocytes. Aminoguanidine, an inhibitor of iNOS, significantly attenuated these LPS-induced functional and metabolic changes. Myocardial cyclic guanosine 3',5'-monophosphate (cGMP) content was significantly increased after LPS injection. Methylene blue, an inhibitor of soluble guanylate cyclase, blunted this increase in cGMP and significantly restored the LPS-induced contractile dysfunction 6 h after LPS injection. In addition, there was a significant negative correlation between LVDP and myocardial cGMP levels as well as a significant negative correlation between LVDP and plasma NO(x) levels. In contrast, 48 h after LPS injection, methylene blue no longer affected cardiac performance, and there was a significant positive correlation between LVDP and myocardial ATP content. Furthermore, the normalized activities (as a ratio of the citrate synthase activity) of mitochondrial NADH-CoQ reductase, succinate-CoQ reductase, and ATPase, were significantly inhibited, and the swelling or disruption of mitochondria cristae was seen in the 48 h LPS treatment. These LPS-induced functional and morphological disorders in the mitochondria were significantly improved by aminoguanidine. The findings suggest that sustained production of NO by iNOS leads to contractile dysfunction via cGMP in the early stage, but that it can directly impair the mitochondrial function, lower myocardial energy production, and contribute significantly to the myocardial dysfunction in the later stage of septic shock.
- Published
- 2004
167. Papillary fibroelastoma of the aortic valve: evaluation with transesophageal echocardiography and magnetic resonance imaging
- Author
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Jun, Shiraishi, Masashi, Tagawa, Takashi, Yamada, Takahisa, Sawada, Tetsuya, Tatsumi, Akihiro, Azuma, Yasuyuki, Shimada, Hitoshi, Yaku, Nobuo, Kitamura, and Masao, Nakagawa
- Subjects
Male ,Echocardiography ,Evaluation Studies as Topic ,Aortic Valve ,Heart Valve Diseases ,Humans ,Fibroma ,Magnetic Resonance Imaging ,Echocardiography, Transesophageal ,Aged - Abstract
A 74-year-old Japanese male was admitted to hospital with episodes of chest pain. Cross-sectional echocardiography showed a mobile mass adherent to the noncoronary cusp of the aortic valve. We employed transesophageal echocardiography and magnetic resonance imaging to evaluate the mass. Based on the findings, a papillary fibroelastoma of the aortic valve was suspected. To avoid systemic embolization, urgent surgery was performed. The histopathologic diagnosis was papillary fibroelastoma. When a tumor of the aortic valve exists, these examinations are useful in detecting and characterizing the tumor for optimal treatment.
- Published
- 2003
168. Nitric oxide-cGMP pathway is involved in endotoxin-induced contractile dysfunction in rat hearts
- Author
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Satoaki Matoba, Kazuko Akashi, Jun Shiraishi, Susumu Nishikawa, Mitsuo Takeda, Miyuki Kobara, Tetsuya Tatsumi, Jun Asayama, Natsuya Keira, Satoshi Yamanaka, Masao Nakagawa, Akiko Mano, and Henry Fliss
- Subjects
Male ,medicine.medical_specialty ,Physiology ,In Vitro Techniques ,Nitric Oxide ,Nitric oxide ,Rats, Sprague-Dawley ,chemistry.chemical_compound ,Ventricular Dysfunction, Left ,Physiology (medical) ,Internal medicine ,Medicine ,Animals ,Cyclic GMP ,chemistry.chemical_classification ,biology ,business.industry ,Septic shock ,Myocardium ,medicine.disease ,Myocardial Contraction ,Rats ,Nitric oxide synthase ,Endotoxins ,Enzyme ,Endocrinology ,chemistry ,Shock (circulatory) ,Circulatory system ,biology.protein ,medicine.symptom ,business ,Signal Transduction - Abstract
The mechanisms by which endotoxemia causes cardiac depression have not been fully elucidated. The present study examined the involvement of nitric oxide (NO) in this pathology. Rats were infused with lipopolysaccharide (LPS) or saline, and the plasma and myocardial [Formula: see text] and [Formula: see text] (NOx) concentrations were measured before or 3, 6, and 24 h after treatment. The hearts were then immediately isolated and mounted in a Langendorff apparatus, and left ventricular developed pressure (LVDP) was determined before biochemical analysis of the myocardium. LPS injection effected the expression of inducible NO synthase (iNOS) in the myocardium, a marked increase in plasma and myocardial NOx levels, and a significant decline in LVDP compared with saline controls. The LPS-induced NO production and concomitant cardiac depression were most pronounced 6 h after LPS injection and were accompanied by a significant increase in myocardial cGMP content. Myocardial ATP levels were not significantly altered after LPS injection. Significant negative correlation was observed between LVDP and myocardial cGMP content, as well as between LVDP and plasma NOx levels. Aminoguanidine, an inhibitor of iNOS, significantly attenuated the LPS-induced NOx production and contractile dysfunction. Furthermore, 1 H-[1,2,4]oxadiazolo[4,3- a]quinoxalin-1-one, an inhibitor of soluble guanylate cyclase, significantly decreased myocardial cGMP content and attenuated the contractile depression, although aminoguanidine or 1 H-[1,2,4]oxadiazolo[4,3- a]quinoxalin-1-one was not able to completely reverse myocardial dysfunction. Our data suggest that endotoxin-induced contractile dysfunction in rat hearts is associated with NO production by myocardial iNOS and a concomitant increase in myocardial cGMP.
- Published
- 2003
169. Echocardiographic diagnosis of pulmonary vein varix
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Miyuki Kobara, Daisuke Kambayashi, Masao Nakagawa, Masaki Kimata, Akihiro Azuma, Akiko Mano, Satoshi Yamanaka, Jun Shiraishi, and Tetsuya Tatsumi
- Subjects
medicine.medical_specialty ,Pulmonary vein ,Diagnosis, Differential ,Varicose Veins ,medicine ,Pulmonary angiography ,Humans ,Varix ,medicine.diagnostic_test ,business.industry ,Vascular disease ,Angiography ,Magnetic resonance imaging ,General Medicine ,Middle Aged ,medicine.disease ,Magnetic Resonance Imaging ,Echocardiography ,Pulmonary Veins ,cardiovascular system ,Female ,Radiography, Thoracic ,Radiology ,Cardiology and Cardiovascular Medicine ,Chest radiograph ,business ,Varices ,Echocardiography, Transesophageal - Abstract
Pulmonary vein varix is a rare abnormality, often resembling a pulmonary or mediastinal mass on chest radiographs, and pulmonary angiography has been the mainstay of diagnosis. An unusual case of pulmonary vein varix was clearly defined by echocardiography performed in a 47-year-old woman with chest discomfort who had been found to have an abnormal structure behind the cardiac silhouette on a chest radiograph. The diagnosis of left lower pulmonary vein varix was noninvasively confirmed by transthoracic echocardiography and transesophageal echocardiography.
- Published
- 2003
170. Amlodipine inhibits doxorubicin-induced apoptosis in neonatal rat cardiac myocytes
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Satoaki Matoba, Masao Nakagawa, Jun Asayama, Tetsuya Tatsumi, Satoshi Yamanaka, Henry Fliss, Jun Shiraishi, Shinji Fushiki, Natsuya Keira, and Akiko Mano
- Subjects
medicine.medical_specialty ,Cell Survival ,Blotting, Western ,Apoptosis ,Pharmacology ,Sensitivity and Specificity ,Superoxide dismutase ,chemistry.chemical_compound ,Annexin ,Internal medicine ,medicine ,Myocyte ,Animals ,Drug Interactions ,Myocytes, Cardiac ,Amlodipine ,Cells, Cultured ,Probability ,Analysis of Variance ,biology ,business.industry ,Cytochrome c ,Glutathione ,Ascorbic acid ,Rats ,Oxidative Stress ,Endocrinology ,chemistry ,Animals, Newborn ,Doxorubicin ,Models, Animal ,biology.protein ,business ,Cardiology and Cardiovascular Medicine ,medicine.drug - Abstract
ObjectivesWe examined whether amlodipine, a calcium channel antagonist with potent antioxidant activity, inhibits doxorubicin-induced apoptosis in cultured neonatal rat cardiac myocytes.BackgroundRecent studies have shown that doxorubicin induces apoptosis as well as necrosis in myocytes through generation of reactive oxygen species.MethodsThe effects of amlodipine and several other antioxidants on doxorubicin-induced oxidative stress and mitochondria-mediated apoptosis were examined.ResultsTreatment of myocytes with doxorubicin (10−6mol/l) for 14 h increased the number of cells with elevated peroxides, as histochemically estimated by 2′,7′-dichlorofluorescin (DCF) diacetate, and the percentage of apoptotic myocytes, as estimated by Hoechst 33258 nuclear staining, compared with control myocytes (25.0 ± 1.6% vs. 5.2 ± 1.2%). Moreover, doxorubicin-induced myocyte apoptosis was also confirmed by annexin V–fluorescein isothiocyanate binding assay. Doxorubicin induced a reduction in myocyte adenosine 5′-triphosphate content, a loss of mitochondrial membrane potential, cytochrome crelease from the mitochondria into the cytosol, and caspase-3 activation to 1.9-fold of control. Amlodipine significantly attenuated increased DCF fluorescence, inhibited the mitochondria-mediated apoptotic responses described earlier, and decreased apoptosis in the doxorubicin-treated myocytes in a dose-dependent fashion. Amlodipine at 10−6mol/l significantly decreased apoptosis to 15.4 ± 0.7%, and this antiapoptotic action was more effective than that seen with other antioxidants, including probucol, ascorbic acid, and alpha-tocopherol. In contrast, the calcium channel antagonist nifedipine (10−6mol/l) did not inhibit apoptosis. Catalase, glutathione, and N-acetylcysteine, but not mannitol or superoxide dismutase, significantly decreased DCF fluorescence and attenuated myocyte apoptosis induced by doxorubicin to 18.7 ± 1.2%, 19.1 ± 1.7%, and 18.7 ± 0.6%, respectively.ConclusionsAmlodipine significantly inhibits doxorubicin-induced myocyte apoptosis by suppressing the mitochondrial apoptotic pathway. This effect is attributed to the antioxidant properties of amlodipine, affecting mainly hydrogen peroxide.
- Published
- 2003
171. Trichosporon cutaneum fungemia in patients with acute myeloblastic leukemia and measurement of serumd-arabinitol,Candida antigen (CAND-TEC), and β-d-glucan
- Author
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T Hirata, Eishi Ashihara, Chihiro Shimazaki, Noboru Yamagata, Y. Hirata, Masanori Nakagawa, Naohisa Fujita, Tetsuya Tatsumi, S. Morimoto, Hideo Goto, and Inaba T
- Subjects
Antigens, Fungal ,Acute myeloblastic leukemia ,Immunocompromised Host ,Sugar Alcohols ,Endophthalmitis ,Trichosporon ,medicine ,Humans ,Glucans ,Mycosis ,Fungemia ,Candida ,biology ,business.industry ,Hematology ,General Medicine ,Middle Aged ,medicine.disease ,biology.organism_classification ,Leukemia, Myeloid, Acute ,Leukemia ,Immunology ,Prednisolone ,Female ,business ,Fluconazole ,medicine.drug - Abstract
Two patients with acute myeloblastic leukemia are described who developed fungemia due to Trichosporon cutaneum. Fungemia occurred at the leukocyte nadir following the administration of anti-cancer chemotherapy. One patient was cured but the other died. Both patients received prednisolone continuously and had central venous catheters in place for parenteral hyperalimentation. T. cutaneum isolates were resistant to 5-fluorocytosine and moderately susceptible to fluconazole. One case was complicated by endophthalmitis due to T. cutaneum; this is the second report of such a complication in the world. We investigated the serum levels of beta-D-glucan, D-arabinitol, and Candida antigen (CAND-TEC); beta-D-glucan was elevated in both cases, which suggests that simultaneous measurements of these laboratory values are useful for the diagnosis and possibly for the evaluation of therapy for this fungal infection.
- Published
- 1994
172. [A 55-year-old man showing sudden disappearance of Q wave]
- Author
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Jun, Shiraishi, Tetsuya, Tatsumi, Shigehiro, Kusuoka, Akihiro, Azuma, and Masao, Nakagawa
- Subjects
Male ,Electrocardiography ,Recurrence ,Myocardial Infarction ,Humans ,Middle Aged - Published
- 2002
173. Lethal effect of cytokine-induced nitric oxide and peroxynitrite on cultured rat cardiac myocytes
- Author
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Satoaki Matoba, Jun Shiraishi, Tetsuya Tatsumi, Henry Fliss, Shinji Fushiki, Masao Nakagawa, Jun Asayama, Kazuko Akashi, Miyuki Kobara, Satoshi Yamanaka, and Natsuya Keira
- Subjects
medicine.medical_specialty ,Necrosis ,medicine.medical_treatment ,Muscle Fibers, Skeletal ,Nitric Oxide Synthase Type II ,Nitric Oxide ,Nitric oxide ,chemistry.chemical_compound ,Adenosine Triphosphate ,Internal medicine ,Peroxynitrous Acid ,medicine ,Cytotoxic T cell ,Myocyte ,Animals ,Molecular Biology ,Cells, Cultured ,Cell Death ,Nitrotyrosine ,Myocardium ,Rats ,Endocrinology ,Cytokine ,chemistry ,Biochemistry ,Uric acid ,Cytokines ,medicine.symptom ,Nitric Oxide Synthase ,Cardiology and Cardiovascular Medicine ,Energy Metabolism ,Peroxynitrite - Abstract
We examined the cytotoxic effect of iNOS-generated NO in cultured cardiac myocytes treated with IL-1 β , IFN- γ and LPS. Treatment of the myocytes with cytokines for 48 h resulted in a marked NO production, a significant decline in cellular ATP content, and a significant increase in myocyte death with morphological characteristics of necrosis. Moreover, immunohistochemical examination showed that the cytokines caused nitrotyrosine formation in the injured myocytes. Uric acid and L-cysteine which have the ability to quench peroxynitrite significantly attenuated these cytokine-induced effects, although they did not alter NO production or the decline in cellular ATP. These data suggest that NO production induced by cytokines can not only cause deleterious effects in the myocardial energy balance but also induce myocytes necrosis, through the formation of peroxynitrite.
- Published
- 2002
174. Characterization of polymer layer formation during SiO2/SiN etching by fluoro/hydrofluorocarbon plasmas
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Tetsuya Tatsumi, Masanaga Fukasawa, Tomoko Ito, Keita Miyake, Satoshi Hamaguchi, Michiro Isobe, Kazunori Nagahata, and Kazuhiro Karahashi
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Ion beam ,General Engineering ,General Physics and Astronomy ,chemistry.chemical_element ,Ion ,chemistry.chemical_compound ,Silicon nitride ,chemistry ,Etching (microfabrication) ,Sputtering ,Fluorine ,Physical chemistry ,Organic chemistry ,Fluorocarbon ,Silicon oxide - Abstract
In reactive-ion etching (RIE) of silicon oxide (SiO2) or silicon nitride (SiN) by fluorocarbon (FC) or hydrofluorocarbon (HFC) plasmas, fluorinated carbon layers may be formed on the etched surfaces and affect their etching rates. In this study, the properties of SiO2 and SiN etching by FC or HFC plasmas are examined in light of the formation mechanism of such carbon layers by molecular dynamics (MD) simulation. Furthermore, in this study, the electronegativity effect of fluorine (F) is taken into account in the interatomic potential functions for C–F and Si–F bonds and MD simulations here show SiO2 and SiN sputtering yields are closer to those obtained from ion beam experiments. It has been found from MD simulations that the SiN sputtering yield during etching by HFC ions is higher than that by FC ions owning to the fact that hydrogen in the HFC ion beam tends to impede the formation of a fluorocarbon layer on SiN and therefore energetic fluorine ions/atoms are more readily available to etch SiN underneath the polymer layer.
- Published
- 2014
175. Dry Process
- Author
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Tetsuya Tatsumi, Keizo Kinoshita, Seiichiro Higashi, Koji Eriguchi, Osamu Sakai, Nobuo Fujiwara, Makoto Sekine, and Takanori Ichiki
- Subjects
Engineering ,Physics and Astronomy (miscellaneous) ,business.industry ,Scientific method ,General Engineering ,General Physics and Astronomy ,Process engineering ,business - Published
- 2014
176. Important role of energy-dependent mitochondrial pathways in cultured rat cardiac myocyte apoptosis
- Author
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Jun Asayama, Satoaki Matoba, Kazuko Akashi, Akiko Mano, Tetsuya Tatsumi, Jun Shiraishi, Masao Nakagawa, Henry Fliss, Takeshi Yaoi, Shinji Fushiki, Natsuya Keira, and Satoshi Yamanaka
- Subjects
Programmed cell death ,Physiology ,Cell Survival ,Apoptosis ,Cytochrome c Group ,Mitochondrion ,Biology ,Mitochondrial apoptosis-induced channel ,Mitochondria, Heart ,Membrane Potentials ,Bcl-2-associated X protein ,Adenosine Triphosphate ,Physiology (medical) ,Proto-Oncogene Proteins ,medicine ,Staurosporine ,Animals ,Enzyme Inhibitors ,Rats, Wistar ,Cells, Cultured ,bcl-2-Associated X Protein ,Caspase 3 ,Myocardium ,Osmolar Concentration ,Biological Transport ,Heart ,Molecular biology ,Cell biology ,Rats ,Enzyme Activation ,Glucose ,Mitochondrial permeability transition pore ,Proto-Oncogene Proteins c-bcl-2 ,Caspases ,biology.protein ,Cyclosporine ,Cardiology and Cardiovascular Medicine ,Energy Metabolism ,Intracellular ,medicine.drug - Abstract
Recent studies have suggested that apoptosis and necrosis share common features in their signaling pathway and that apoptosis requires intracellular ATP for its mitochondrial/apoptotic protease-activating factor-1 suicide cascade. The present study was, therefore, designed to examine the role of intracellular energy levels in determining the form of cell death in cardiac myocytes. Neonatal rat cardiac myocytes were first incubated for 1 h in glucose-free medium containing oligomycin to achieve metabolic inhibition. The cells were then incubated for another 4 h in similar medium containing staurosporine and graded concentrations of glucose to manipulate intracellular ATP levels. Under ATP-depleting conditions, the cell death caused by staurosporine was primarily necrotic, as determined by creatine kinase release and nuclear staining with ethidium homodimer-1. However, under ATP-replenishing conditions, staurosporine increased the percentage of apoptotic cells, as determined by nuclear morphology and DNA fragmentation. Caspase-3 activation by staurosporine was also ATP dependent. However, loss of mitochondrial transmembrane potential (ΔΨm), Bax translocation, and cytochrome crelease were observed in both apoptotic and necrotic cells. Moreover, cyclosporin A, an inhibitor of mitochondrial permeability transition, attenuated staurosporine-induced apoptosis and necrosis through the inhibition of ΔΨmreduction, cytochrome c release, and caspase-3 activation. Our data therefore suggest that staurosporine induces cell demise through a mitochondrial death signaling pathway and that the presence of intracellular ATP favors a shift from necrosis to apoptosis through caspase activation.
- Published
- 2001
177. Hyperleukocytosis in patients with leukemic follicular lymphoma
- Author
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Tetsuya Tatsumi, Chihiro Shimazaki, Akio Okamoto, Tohru Inaba, and Naohisa Fujita
- Subjects
medicine.medical_specialty ,Pathology ,Hematology ,business.industry ,Internal medicine ,medicine ,Follicular lymphoma ,In patient ,General Medicine ,medicine.disease ,business ,Lymphoma - Published
- 2007
178. Dry etching resistance of methacrylate polymers for ArF excimer laser lithography
- Author
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Takuya Naito, Tetsuya Tatsumi, Takeshi Ohfuji, Koichi Kuhara, Makoto Takahashi, Masaru Sasago, and Masayuki Endo
- Subjects
chemistry.chemical_classification ,Materials science ,Excimer laser ,Silicon ,medicine.medical_treatment ,chemistry.chemical_element ,Polymer ,Alicyclic compound ,chemistry ,Resist ,Etching (microfabrication) ,Polymer chemistry ,medicine ,Dry etching ,Composite material ,Lithography - Abstract
We have investigated dry-etching resistance of methacrylate polymers for use as ArF chemically amplified resists and proposed a new etching model that can predict the etching rate very accurately. The examined polymers were methacrylate polymers with alicyclic groups. The polymers were dry etched using a LAM TCP-9400 machine under the chlorine-based gas conditions used for poly-silicon etching. The obtained etching rate was explained in term of a carbon- atom-density parameter known as the ohnishi parameter. However, the fitting accuracy is not good enough especially for alicyclic polymers (R equals 0.87). And a ring parameter model also resulted in a similar fitting accuracy (R equals 0.86). Hence, we proposed a new model that introduced polymer-structure dependence into the carbon-atom-density model. The new model gives excellent agreement with measured data (R equals 0.99). And it is very useful in designing ArF resist polymers and predicting etching resistance of future ArF resists.
- Published
- 1998
179. Erratum to 'Nicorandil regulates Bcl-2 family proteins and protects cardiac myocytes against hypoxia-induced apoptosis' [J. Mol. Cell. Cardiol. 40 (2006) 510–519]
- Author
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Natsuya Keira, Hiroaki Matsubara, Tetsuya Tatsumi, Tomosaburo Takahashi, Mitsuhiko Okigaki, Akiko Mano, Jun Shiraishi, Miyuki Kobara, Shinsaku Matsunaga, Susumu Nishikawa, and Mitsuo Takeda
- Subjects
Chemistry ,Bcl-2 family ,Cell ,Hypoxia (medical) ,medicine.anatomical_structure ,Apoptosis ,Mole ,medicine ,Cancer research ,Myocyte ,medicine.symptom ,Cardiology and Cardiovascular Medicine ,Nicorandil ,Molecular Biology ,medicine.drug - Published
- 2006
180. Instructive percutaneous coronary intervention to avoid the risk of side branch occlusion at a lesion with a lotus root appearance: a case report.
- Author
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Tetsuya Nomura, Taku Kato, Hiroshi Kubota, Daisuke Miyawaki, Ryota Urata, Takeshi Sugimoto, Yusuke Higuchi, Natsuya Keira, Tetsuya Tatsumi, Nomura, Tetsuya, Kato, Taku, Kubota, Hiroshi, Miyawaki, Daisuke, Urata, Ryota, Sugimoto, Takeshi, Higuchi, Yusuke, Keira, Natsuya, and Tatsumi, Tetsuya
- Subjects
PERCUTANEOUS coronary intervention ,ARTERIAL occlusions ,TISSUE wounds ,RIGHT heart ventricle ,OPTICAL coherence tomography ,BIFURCATION theory ,DISEASE risk factors - Abstract
Background: A lotus root appearance is a rare entity, and there is little opportunity to perform coronary intervention for this kind of lesion. Because of its peculiar anatomical characteristics, one of the problems regarding percutaneous coronary intervention (PCI) for these lesions is related to the involvement of branch vessels.Case Presentation: We encountered a case of PCI for a stenotic lesion with a lotus root appearance in the mid-portion of the right coronary artery (RCA). To avoid the risk of right ventricular (RV) branch occlusion due to stent deployment in the main RCA, we re-crossed the third guidewire into the main RCA via the nearest point to the RV branch ostium through the communicating vascular lumen. Thereafter, we deployed a drug-eluting stent in the main RCA crossing over the RV branch, and the ostium of the RV branch remained intact, as we expected.Conclusions: This case is the first report in the world describing the details of how to maintain the patency of the side branch bifurcating from a lesion with a lotus root appearance under optical coherence tomography guidance. [ABSTRACT FROM AUTHOR]- Published
- 2016
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181. Effect of open area ratio and pattern structure on fluctuations in critical dimension and Si recess
- Author
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Takashi Kinoshita, Hiroyuki Miwa, Hisahiro Ansai, Tetsuya Tatsumi, Nobuyuki Kuboi, Masanaga Fukasawa, and Jun Komachi
- Subjects
Materials science ,Silicon ,Solid angle ,Analytical chemistry ,chemistry.chemical_element ,Surfaces and Interfaces ,Plasma ,Photoresist ,Condensed Matter Physics ,Molecular physics ,Surfaces, Coatings and Films ,chemistry ,Etching (microfabrication) ,Wafer ,Critical dimension ,Intensity (heat transfer) - Abstract
The authors quantitatively investigated the effects of open area ratio and pattern structure on fluctuations in critical dimension (ΔCD) and Si recess depth (ΔdR). To model these effects, under the assumption that three factors—mask open area ratio at the wafer level (global), chip level (semi-local), and local level (local)—affect ΔCD and ΔdR, they performed experiments using wafers ranging from 0.60 to 0.91 of the global range (RG) and the semi-local range (RS) treated by the HBr/O2 plasma etching process, where photoresist mask patterns on the poly-Si film with solid angles (ΩL) ranging from 0.2π to 0.9π were located. As a result, the authors found that ΔCD had positive and linear correlation with the RG value, which was consistent with the trend of the integrated intensity of the etched by-product (SiBrx) estimated by optical emission spectroscopy data and with that of taper angles of observed etched profiles. They also clarified that ΔCD was affected by the amount of SiBrx generated within several ti...
- Published
- 2013
182. Photoluminescence Study of Plasma-Induced Damage of GaInN Single Quantum Well
- Author
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Atsushi A. Yamaguchi, Kenji Ishikawa, Shigetaka Tomiya, Tetsuya Tatsumi, Masaki Minami, Michiru Kamada, Masaru Hori, and Shouichiro Izumi
- Subjects
Photoluminescence ,Materials science ,Plasma etching ,business.industry ,General Engineering ,General Physics and Astronomy ,Plasma ,Transmission electron microscopy ,Etching (microfabrication) ,Optoelectronics ,business ,Recombination ,Intensity (heat transfer) ,Quantum well - Abstract
Plasma-induced damage (PID) due to Cl2/SiCl4/Ar plasma etching of the GaN capping layer (CAP)/GaInN single quantum well (SQW)/GaN structure was investigated by conventional photoluminescence (PL), transmission electron microscopy (TEM), and time-resolved and temperature-dependent photoluminescence (TRPL). SQW PL intensity remained constant initially, although plasma etching of the CAP layer proceeded, but when the etching thickness reached a certain amount (∼60 nm above the SQW), PL intensity started to decrease sharply. On the other hand, TEM observations show that the physical damage (structural damage) was limited to the topmost surface region. These findings can be explained by the results of TRPL studies, which revealed that there exist two different causes of PID. One is an increase in the number of nonradiative recombination centers, which mainly affects the PL intensity. The other is an increase in the quantum level fluctuation owing mainly to physical damage.
- Published
- 2013
183. Wavelength Dependence of Photon-Induced Interface Defects in Hydrogenated Silicon Nitride/Si Structure during Plasma Etching Processes
- Author
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Kazunori Nagahata, Tetsuya Tatsumi, Fumikatsu Uesawa, Keigo Takeda, Hiroyasu Matsugai, Yusuke Kondo, Masanaga Fukasawa, Makoto Sekine, Takahiro Honda, Yudai Miyawaki, Masaru Hori, Hiroki Kondo, and Kenji Ishikawa
- Subjects
Interface layer ,Plasma etching ,Photon ,Materials science ,business.industry ,Interface (computing) ,General Engineering ,General Physics and Astronomy ,Dielectric ,Radiation ,chemistry.chemical_compound ,Wavelength ,Silicon nitride ,chemistry ,Optoelectronics ,business - Abstract
The wavelength dependence of SiN x :H/Si interface defect generation caused by vacuum ultraviolet (VUV)/UV radiation from plasma etching processes was investigated. VUV radiation (λ< 200 nm) had almost no impact on the generation of defects at the SiN x :H/Si interface, since all the radiation in this wavelength range was absorbed in the upper SiN x :H film. However, UV radiation (200 < λ< 400 nm) was able to reach the underlying SiN x :H/Si interface and damage the interface. Direct UV radiation reaching the SiN x :H/Si interface dissociated the chemical bonds at the interface and generated interface-trapped charges. The estimated total energy of absorbed photons (E total; 200 < λ< 400 nm) at the interface layer seems to be proportional to the interface-trapped charge density (D it) measured by capacitance–voltage measurement. However, the mechanism underlying the relationship between E total and D it is not yet clear. Visible radiation (λ> 400 nm) had no influence on damage generation on the SiN x :H/Si structure, since the visible radiation was transmitted through upper SiN x :H film and underlying interface layer. The results revealed that UV radiation transmitted through the upper dielectrics can cause the electrical characteristics of underlying metal–oxide–semiconductor (MOS) devices to fluctuate.
- Published
- 2013
184. Effect of ischemic preconditioning on mitochondrial oxidative phosphorylation and high energy phosphates in rat hearts
- Author
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Satoaki Matoba, Miyuki Kobara, Daisuke Inoue, Chiaki Nakagawa, Tetsuya Tatsumi, Yasuhiro Yamahara, Masao Nakagawa, Jun Asayama, Bon Ohta, and Takashi Matsumoto
- Subjects
High-energy phosphate ,Male ,medicine.medical_specialty ,Phosphocreatine ,ATPase ,Ischemia ,Myocardial Ischemia ,Myocardial Reperfusion Injury ,Oxidative phosphorylation ,Mitochondria, Heart ,Oxidative Phosphorylation ,Rats, Sprague-Dawley ,Adenosine Triphosphate ,Adenine nucleotide ,Internal medicine ,medicine ,Animals ,Anaerobiosis ,Lactic Acid ,Molecular Biology ,Creatine Kinase ,Cardioprotection ,Adenosine Triphosphatases ,biology ,medicine.disease ,Creatine ,Rats ,Endocrinology ,Biochemistry ,Anaerobic glycolysis ,Evaluation Studies as Topic ,biology.protein ,Lactates ,Ischemic preconditioning ,Cardiology and Cardiovascular Medicine ,Glycolysis ,Mitochondrial ADP, ATP Translocases - Abstract
The ability of ischemic preconditioning (IP) to protect the myocardium against prolonged ischemia may derive from improved energy balance. We therefore examined myocardial energy metabolism and mitochondrial oxidative phosphorylation in isolated perfused rat hearts which were either subjected (IP group), or not subjected (control group), to preconditioning prior to 30 min sustained ischemia and 30 min reperfusion. Preconditioning was achieved with two cycles of 5 min ischemia followed by 5 min reperfusion. Recovery of myocardial function was significantly greater, and creatine kinase release was significantly lower, in the IP group. Although ATP hydrolysis during the sustained ischemia remained unchanged in both groups, greater preservation of high energy phosphate (eg. ATP and CP) was observed in the IP group after reperfusion. CP content immediately after preconditioning greatly exceeded pre-ischemic values. Lactate production during the sustained ischemia was significantly lower in the IP group, suggesting a decrease in anaerobic glycolysis and a probable attenuation of intracellular acidosis. Oligomycin-sensitive mitochondrial ATPase activity in the control group was significantly decreased both after the sustained ischemia and the reperfusion, but in the IP group it did not change after the preconditioning, sustained ischemia, or reperfusion. Although atractyloside-inhibitable adenine nucleotide translocase activity was markedly decreased during sustained ischemia in both groups, its activity was significantly higher after reperfusion in the IP group. These data suggest that (1) mitochondrial ATPase contributes only slightly to ATP depletion during sustained ischemia, (2) both the CP overshoot phenomenon and the decrease in anaerobic glycolysis can be attributable to cardioprotection during the sustained ischemia, and (3) the preservation of ATPase and adenine nucleotide translocase activities may be a possible explanation for the restoration of high energy phosphates after sustained ischemia-reperfusion injury in the preconditioned hearts of rats.
- Published
- 1996
185. Cardioprotective Effect of Taurine on Calcium Paradox in Streptozotocin-Induced Diabetic Rat Hearts
- Author
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Miyuki Kobara, Tetsuya Tanaka, Kouki Tsuruyama, Satoaki Matoba, Masao Nakagawa, Akira Kawahara, Jun Asayama, Chiaki Nakagawa, Bon Ohta, and Tetsuya Tatsumi
- Subjects
High-energy phosphate ,Taurine ,medicine.medical_specialty ,Protein metabolism ,Metabolism ,Carbohydrate ,medicine.disease ,Streptozotocin ,chemistry.chemical_compound ,Endocrinology ,chemistry ,Diabetes mellitus ,Internal medicine ,Organelle ,medicine ,medicine.drug - Abstract
Through the modification of Ca2+ metabolism, taurine is known to have several beneficial physiological actions, including antiarrhythmic18, positive inotropic2–4, and membrane stabilizing effects7. In addition, it has been reported that taurine protects the heart against Ca2+ paradox-induced myocardial injury9. However, it is unclear whether taurine has a similar cardioprotective effect in diabetic hearts, which exhibit a number of alterations in metabolism. Diabetes mellitus is a disorder of carbohydrate, lipid, and protein metabolism affecting many organs. In addition to contractile abnormalities, previous studies revealed disturbances in function of subcellular organelles in diabetic hearts, including impaired glucose utilization, mitochondrial dysfunction, and depressed Na+-Ca2+ Na+-H+ exchange activities12, 17, 22.
- Published
- 1996
186. Modeling and Simulation of Plasma-Induced Damage Distribution during Hole Etching of SiO$_{2}$ over Si Substrate by Fluorocarbon Plasma
- Author
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Nobuyuki Kuboi, Tetsuya Tatsumi, Takashi Kinoshita, Hisahiro Ansai, Shoji Kobayashi, Jun Komachi, and Masanaga Fukasawa
- Subjects
chemistry.chemical_classification ,Materials science ,Plasma etching ,General Engineering ,Analytical chemistry ,General Physics and Astronomy ,Polymer ,Plasma ,Ion ,Modeling and simulation ,chemistry ,Etching (microfabrication) ,Fluorocarbon ,Reactive-ion etching ,Composite material - Abstract
We developed a plasma etching simulation with our new concept in order to predict the distribution of plasma-induced damage during contact hole etching of SiO2 over Si substrate using fluorocarbon plasma (C4F8/O2/Ar). Our model included plasma database, gas transport (direct and indirect fluxes of ions and radicals), surface reaction considering depth effect, and damage distribution. We could demonstrate how to evolve the Si damage in main and overetching steps, which is realistically difficult to measure. Our results show that polymer thickness, overetching time, and etched profile should be carefully controlled to reduce physical damage.
- Published
- 2012
187. Effect of doxorubicin on postrest contraction in isolated rat hearts
- Author
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Tetsuya Tatsumi, Satoaki Matoba, Masao Nakagawa, Tetsuya Tanaka, Daisuke Inoue, Chiaki Nakagawa, Jun Asayama, Bon Ohta, and Miyuki Kobara
- Subjects
medicine.medical_specialty ,Contraction (grammar) ,Cardiomyopathy ,Biology ,In Vitro Techniques ,Ouabain ,Rats, Sprague-Dawley ,Internal medicine ,Caffeine ,Heart rate ,medicine ,Animals ,Doxorubicin ,Pharmacology ,Cardiotoxicity ,Antibiotics, Antineoplastic ,medicine.disease ,Myocardial Contraction ,Rats ,Sarcoplasmic Reticulum ,Endocrinology ,Vacuolization ,Circulatory system ,Calcium ,Cardiology and Cardiovascular Medicine ,medicine.drug - Abstract
Clinical use of doxorubicin is limited by its cardiotoxicity. In doxorubicin-induced cardiomyopathy, vacuolization of the sarcoplasmic reticulum (SR) has been reported. We investigated whether doxorubicin had a direct action on the sarcoplasmic reticulum (SR) in isolated perfused rat hearts. The left and right atria were trimmed to maintain heart rate (HR)
- Published
- 1995
188. Effect of nicorandil on cardiac dysfunction during reperfusion in normotensive and spontaneously hypertensive rats
- Author
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Tetsuya Tatsumi, Daisuke Inoue, Bon Ohta, Yasuhiro Yamahara, Satoaki Matoba, Chiaki Nakagawa, Masao Nakagawa, Miyuki Kobara, and Jun Asayama
- Subjects
Male ,Niacinamide ,medicine.medical_specialty ,Physiology ,Ischemia ,Blood Pressure ,Myocardial Reperfusion ,Rats, Inbred WKY ,Ventricular Function, Left ,Spontaneously hypertensive rat ,Heart Rate ,Reference Values ,Internal medicine ,Coronary Circulation ,Rats, Inbred SHR ,Internal Medicine ,medicine ,Animals ,cardiovascular diseases ,Nicorandil ,Creatine Kinase ,Antihypertensive Agents ,Dose-Response Relationship, Drug ,business.industry ,Hemodynamics ,Heart ,General Medicine ,medicine.disease ,Potassium channel ,Rats ,Preload ,Hypertension ,cardiovascular system ,Cardiology ,End-diastolic volume ,business ,Reperfusion injury ,Perfusion ,medicine.drug - Abstract
The cardioprotective effect of nicorandil, an opener of ATP-sensitive potassium channels, was studied in the isolated perfused hearts of the spontaneously hypertensive rat (SHR) and normotensive Wistar-Kyoto (WKY) rat. The hearts were subjected to 30 min of global ischemia followed by 30 min of reperfusion. Controls received no drug. In the nicorandil group, the hearts were treated with 0.03 to 0.3 mmol/L nicorandil for 15 min before ischemia. Left ventricular developed pressure (LVDP) and end diastolic pressure (LVEDP) at 30 min of reperfusion were significantly lower and larger, respectively, in SHR than in WKY rats. Nicorandil improved LVDP and decreased LVEDP at 30 min of reperfusion in both SHR and WKY rats dose-dependently. The hypertensive heart in the early stage is already susceptible to reperfusion-cardiac dysfunction. Nicorandil has a beneficial effect on the post-ischemic dysfunction in both SHR and WKY rats.
- Published
- 1995
189. Vacuum Ultraviolet and Ultraviolet Radiation-Induced Effect of Hydrogenated Silicon Nitride Etching: Surface Reaction Enhancement and Damage Generation
- Author
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Masanaga Fukasawa, Yudai Miyawaki, Yusuke Kondo, Keigo Takeda, Hiroki Kondo, Kenji Ishikawa, Makoto Sekine, Hiroyasu Matsugai, Takayoshi Honda, Masaki Minami, Fumikatsu Uesawa, Masaru Hori, and Tetsuya Tatsumi
- Subjects
Physics and Astronomy (miscellaneous) ,General Engineering ,General Physics and Astronomy - Published
- 2012
190. Vacuum Ultraviolet and Ultraviolet Radiation-Induced Effect of Hydrogenated Silicon Nitride Etching: Surface Reaction Enhancement and Damage Generation
- Author
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Kenji Ishikawa, Yusuke Kondo, Makoto Sekine, Tetsuya Tatsumi, Masaru Hori, Takayoshi Honda, Fumikatsu Uesawa, Hiroki Kondo, Yudai Miyawaki, Masanaga Fukasawa, Masaki Minami, Hiroyasu Matsugai, and Keigo Takeda
- Subjects
Materials science ,business.industry ,Radical ,General Engineering ,General Physics and Astronomy ,Plasma ,Radiation ,medicine.disease_cause ,Wavelength ,chemistry.chemical_compound ,Silicon nitride ,chemistry ,Etching (microfabrication) ,medicine ,Optoelectronics ,business ,Plasma processing ,Ultraviolet - Abstract
Photon-enhanced etching of SiN x :H films caused by the interaction between vacuum ultraviolet (VUV)/ultraviolet (UV) radiation and radicals in the fluorocarbon plasma was investigated by a technique with a novel sample setup of the pallet for plasma evaluation. The simultaneous injection of UV radiation and radicals causes a dramatic etch rate enhancement of SiN x :H films. Only UV radiation causes the film shrinkage of SiN x :H films owing to hydrogen desorption from the film. Capacitance–voltage characteristics of SiN x :H/Si substrates were studied before and after UV radiation. The interface trap density increased monotonically upon irradiating the UV photons with a wavelength of 248 nm. The estimated effective interface trap generation probability is 4.74 ×10-7 eV-1·photon-1. Therefore, the monitoring of the VUV/UV spectra during plasma processing and the understanding of its impact on the surface reaction, film damage and electrical performance of underlying devices are indispensable to fabricate advanced devices.
- Published
- 2012
191. Numerical Simulation Method for Plasma-Induced Damage Profile in SiO2Etching
- Author
-
Nobuyuki Kuboi, Takashi Kinoshita, Jun Komachi, Masanaga Fukasawa, Hisahiro Ansai, Tetsuya Tatsumi, and Shoji Kobayashi
- Subjects
Materials science ,Plasma etching ,Physics and Astronomy (miscellaneous) ,Analytical chemistry ,General Engineering ,General Physics and Astronomy ,Plasma ,Isotropic etching ,Volumetric flow rate ,Etching (microfabrication) ,Surface layer ,Reactive-ion etching ,Composite material ,Layer (electronics) - Abstract
We developed a numerical simulation method for the depth profiles of plasma-induced physical damage to SiO2 and Si layers during fluorocarbon plasma etching. In the proposed method, the surface layer is assumed to consist of two layers: a C–F polymer layer and a reactive layer. Physical and chemical reactions in the reactive layer divided into several thin slabs and in the deposited C–F polymer layer, which depend on etching parameters, such as etching time, gas flow rate, gas pressure, and ion energy (V pp), are considered in detail. We used our simulation method to calculate the SiO2 etch rate, the thickness of the C–F polymer layer (T C–F), and the selectivity of SiO2 to Si during C4F8/O2/Ar plasma etching. We confirmed that the calculated absolute values and their behavior are consistent with experimental data. We also successfully predicted depth profiles of physical damage to the Si and SiO2 layers introducing our re-gridding method. We found that much Si damage is generated in the pre- and early stages of the overetching step of SiO2/Si layer etching despite the high selectivity. These simulation results suggest that the T C–F value and the overetching time must be carefully controlled by process parameters to reduce damage during fluorocarbon plasma etching. The results have also provided us with useful knowledge for controlling the etching process.
- Published
- 2011
192. Hydrogen effects in hydrofluorocarbon plasma etching of silicon nitride: Beam study with CF+, CF2+, CHF2+, and CH2F+ ions
- Author
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Tetsuya Tatsumi, Tomoko Ito, Satoshi Hamaguchi, Kazuhiro Karahashi, and Masanaga Fukasawa
- Subjects
Plasma etching ,Ion beam ,Hydrogen ,Inorganic chemistry ,chemistry.chemical_element ,Surfaces and Interfaces ,Condensed Matter Physics ,Surfaces, Coatings and Films ,Ion ,chemistry ,Etching (microfabrication) ,Fluorine ,Reactive-ion etching ,Ion beam-assisted deposition - Abstract
Tomoko Ito and Kazuhiro Karahashi, Journal of Vacuum Science & Technology A 29, 050601 (2011) https://doi.org/10.1116/1.3610981, Hydrogen in hydrofluorocarbon plasmas plays an important role in silicon nitride (Si3N4) reactive ion etching. This study focuses on the elementary reactions of energetic CHF 2 + and CH2F+ ions with Si3N4 surfaces. In the experiments, Si 3N4 surfaces were irradiated by monoenergetic (500-1500 eV) beams of CHF2+ and CH2F+ ions as well as hydrogen-free CF2+ and CF+ ions generated by a mass-selected ion beam system and their etching yields and surface properties were examined. It has been found that, when etching takes place, the etching rates of Si3N4 by hydrofluorocarbon ions, i.e., CHF2+ and CH2F+, are higher than those by the corresponding fluorocarbon ions, i.e., CF 2+ and CF+, respectively. When carbon film deposition takes place, it has been found that hydrogen of incident hydrofluorocarbon ions tends to scavenge fluorine of the deposited film, reducing its fluorine content. © 2011 American Vacuum Society.
- Published
- 2011
193. Si Recess of Polycrystalline Silicon Gate Etching: Damage Enhanced by Ion Assisted Oxygen Diffusion
- Author
-
Kazuhiro Karahashi, Tetsuya Tatsumi, Satoshi Hamaguchi, Masanaga Fukasawa, and Tomoko Ito
- Subjects
Physics and Astronomy (miscellaneous) ,Radical ,Oxide ,Analytical chemistry ,General Engineering ,chemistry.chemical_element ,General Physics and Astronomy ,Plasma ,engineering.material ,Oxygen ,Ion ,chemistry.chemical_compound ,Polycrystalline silicon ,chemistry ,Chemical engineering ,Etching (microfabrication) ,engineering ,Layer (electronics) - Abstract
The cause of Si recess (i.e., formation of shallow hollows on a Si surface after removal of an oxide layer from the Si surface in a polycrystalline silicon gate etching process by a HBr plasma) has been identified as ion assisted oxygen diffusion, i.e., oxygen diffusion enhanced by hydrogen ion bombardment from the plasma. Both plasma and multi-beam experiments were employed for the analysis of this oxidation mechanism. It has been also found in the analysis that oxidation of a Si surface exposed to oxygen radicals is significantly enhanced only if the surface is subject to both oxygen radical supply and energetic hydrogen ion bombardment simultaneously.
- Published
- 2011
194. Analysis of GaN Damage Induced by Cl2/SiCl4/Ar Plasma
- Author
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Masanaga Fukasawa, Kenji Ishikawa, Makoto Sekine, Masaki Minami, Tetsuya Tatsumi, Masaru Hori, Shang Chen, Fumikatsu Uesawa, Ryosuke Matsumoto, and Shigetaka Tomiya
- Subjects
Plasma etching ,Materials science ,Photoluminescence ,Physics and Astronomy (miscellaneous) ,Ion beam ,business.industry ,technology, industry, and agriculture ,General Engineering ,Analytical chemistry ,General Physics and Astronomy ,Ion ,Etching (microfabrication) ,Optoelectronics ,Irradiation ,Reactive-ion etching ,Inductively coupled plasma ,business - Abstract
GaN-based optical devices are fabricated using a GaN/InGaN/GaN sandwiched structure. The effect of radicals, ions, and UV light on the GaN optical properties during Cl2/SiCl4/Ar plasma etching was evaluated using photoluminescence (PL) analysis. The samples were exposed to plasma (radicals, ions, and UV light) using an inductively coupled plasma (ICP) etching system and a plasma ion beam apparatus that can separate the effects of UV and ions both with and without covering the SiO2 window on the surface. Etching damage in an InGaN single quantum well (SQW) was formed by exposing the sample to plasma. The damage, which decreases PL emission intensity, was generated not only by ion beam irradiation but also by UV light irradiation. PL intensity decreased when the thickness of the upper GaN layer was etched to less than 60 nm. In addition, simultaneous irradiation of UV light and ions slightly increased the degree of damage. There seems to be a synergistic effect between the UV light and the ions. For high-quality GaN-based optoelectronics and power devices, UV light must be controlled during etching processes in addition to the etching profile, selectivity, and ion bombardment damage.
- Published
- 2011
195. Actions of low- and high-energy electrons on the phase transition between E- and H-modes in an inductively coupled plasma in Ar
- Author
-
Toshiaki Makabe, Yuichiro Hayashi, Yo Mitsui, and Tetsuya Tatsumi
- Subjects
Electromagnetic field ,Physics ,Phase transition ,Physics::Plasma Physics ,Excited state ,Inductively coupled plasma atomic emission spectroscopy ,Plasma parameter ,General Physics and Astronomy ,Electron ,Inductively coupled plasma ,Atomic physics ,Excitation - Abstract
It is known that an inductively coupled plasma (ICP) sustained by a radiofrequency current coil has a mode transition and hysteresis characteristics of the internal plasma parameter as a function of the external plasma parameter. We focus on the contributions of low- and high-energy electrons to the phase transition between the capacitive E-mode and the inductive H-mode in an ICP. Our analysis is based on the diagnostics for a time-resolved two-dimensional net excitation rate of short-lived excited atoms, mainly produced collisionally by low- and high-energy electrons by using an intensified charge coupled device optical image. Short-lived excited atoms Ar(2p1) and Ar(2p9) with different excitation processes have been employed as optical probes in an axisymmetric configuration of the ICP chamber, driven at 13.56?MHz by an external single-turn current coil at 300?mTorr in pure Ar. The E-to-H transition is characterized by two time constants of electrons: establishment of an axisymmetric distribution by electron diffusion and the accumulation of symmetric high-density electrons in order to sustain the inductive discharge under a weak electromagnetic field. On the other hand, the H-to-E transition is strongly influenced by the presence of a long-lived excited atom (i.e. metastables).
- Published
- 2011
196. Structural and electrical characterization of HBr/O2 plasma damage to Si substrate
- Author
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Kouichi Ono, Asahiko Matsuda, Yoshinori Takao, Koji Eriguchi, Yoshinori Nakakubo, Fumikatsu Uesawa, Masanaga Fukasawa, Masaki Minami, and Tetsuya Tatsumi
- Subjects
Silicon ,Analytical chemistry ,chemistry.chemical_element ,Surfaces and Interfaces ,Plasma ,Substrate (electronics) ,Condensed Matter Physics ,Crystallographic defect ,Surfaces, Coatings and Films ,Ion ,chemistry ,Transmission electron microscopy ,Ellipsometry ,Layer (electronics) - Abstract
Silicon substrate damage caused by HBr/O2 plasma exposure was investigated by spectroscopic ellipsometry (SE), high-resolution Rutherford backscattering spectroscopy, and transmission electron microscopy. The damage caused by H2, Ar, and O2 plasma exposure was also compared to clarify the ion-species dependence. Although the damage basically consists of a surface oxidized layer and underlying dislocated Si, the damage structure strongly depends on the incident ion species, ion energy, and oxidation during air and plasma exposure. In the case of HBr/O2 plasma exposure, hydrogen generated the deep damaged layer (∼10 nm), whereas ion-enhanced diffusion of oxygen, supplied simultaneously by the plasma, caused the thick surface oxidation. In-line monitoring of damage thicknesses by SE, developed with an optimized optical model, showed that the SE can be used to precisely monitor damage thicknesses in mass production. Capacitance–voltage (C–V) characteristics of a damaged layer were studied before and after dil...
- Published
- 2011
197. Workshop on atomic and molecular collision data for plasma modelling: database needs for semiconductor plasma processing
- Author
-
Toshiaki Makabe and Tetsuya Tatsumi
- Subjects
Plasma etching ,Database ,Semiconductor device fabrication ,Chemistry ,technology, industry, and agriculture ,Plasma ,Condensed Matter Physics ,computer.software_genre ,Ion ,Etching (microfabrication) ,Molecule ,Deposition (phase transition) ,sense organs ,computer ,Plasma processing - Abstract
The process time for semiconductor fabrication has a great influence on both the gas phase and the material surface. We have to consider two specific phenomena when we simulate, predict or design a plasma process for materials. One is the temporal change in the plasma structure and function through the change in feed gas molecules, and the other is the temporal change in surface morphology. On the other hand, the plasma surface process is a competition among etching, deposition and charging caused by active ions and neutral radicals incident on the surface. We show and discuss the present stage of the database in the gas phase and on the surface phase of plasma etching employed in semiconductor manufacturing.
- Published
- 2011
198. Mechanism of plasma-induced damage to low-k SiOCH films during plasma ashing of organic resists
- Author
-
Kazunori Nagahata, Masaru Hori, Tetsuya Tatsumi, Keigo Takeda, Keiji Oshima, Masanaga Fukasawa, Seigo Takashima, and Yudai Miyawaki
- Subjects
Ashing ,Resist ,Ellipsometry ,Chemistry ,Radical ,Analytical chemistry ,General Physics and Astronomy ,Plasma ,Thin film ,Photochemistry ,Plasma ashing ,Ion - Abstract
Plasma-induced damage to porous SiOCH (p-SiOCH) films during organic resist film ashing using dual-frequency capacitively coupled O2 plasmas was investigated using the pallet for plasma evaluation method developed by our group. The damage was characterized by ellipsometry and Fourier-transform infrared spectroscopy. Individual and synergetic damage associated with vacuum ultraviolet (VUV) and UV radiation, radicals, and ions in the O2 plasma were clarified. It was found that the damage was caused not only by radicals but also by synergetic reactions of radicals with VUV and UV radiation emitted by the plasmas. It is noteworthy that the damage induced by plasma exposure without ion bombardment was larger than the damage with ion bombardment. These results differed from those obtained using an H2/N2 plasma for resist ashing. Finally, the mechanism of damage to p-SiOCH caused by O2 and H2/N2 plasma ashing of organic resist films is discussed. These results are very important in understanding the mechanism of...
- Published
- 2011
199. Electrophysiological effects of flecainide acetate on stretched guinea pig left atrial muscle fibers
- Author
-
Tetsuya Tatsumi, Masao Nakagawa, Daisuke Inoue, Ryuta Sakai, Miho Inoue, Yasuhiro Yamahara, Itsuki Omori, Hiroshi Miyazaki, Kazuya Ishibashi, Takeshi Shirayama, and Jun Asayama
- Subjects
Male ,medicine.medical_specialty ,Guinea Pigs ,Flecainide Acetate ,Membrane Potentials ,Nuclear magnetic resonance ,Internal medicine ,Medicine ,Repolarization ,Animals ,Pharmacology (medical) ,Heart Atria ,Flecainide ,Pharmacology ,Membrane potential ,business.industry ,Effective refractory period ,Heart ,General Medicine ,Resting potential ,Electrophysiology ,Endocrinology ,Female ,medicine.symptom ,Cardiology and Cardiovascular Medicine ,business ,Muscle contraction ,medicine.drug - Abstract
The electrophysiological effects of flecainide acetate (3 x 10(-6) M) on stretched atrial tissue were investigated using guinea-pig left atrial muscle fibers. Before stretching, the resting membrane potential was not affected by flecainide at 1 Hz, although the overshoot potential (Eov) and the action potential duration at 50% repolarization (APD50) were slightly but significantly decreased by 2 +/- 1 mV and 2 +/- 1 msec, respectively. The effective refractory period (ERP) was increased by 3 +/- 1 msec. The reduction of Vmax was 20.6 +/- 1.2%. The half-maximum potential (Vh) of the relationship between Vmax and the resting potential was shifted to become more negative by flecainide (from -60.6 +/- 2.1 mV to -63.2 +/- 1.7 mV). After 90-120 min of washout with drug-free Tyrode's solution, the tissue was mechanically stretched to 150% of its slack length. Stretching significantly decreased the Vmax by 16.9 +/- 3.1%, along with a slight but significant increase in ERP (3 +/- 1 msec) and shifted Vh to become more negative (from -60.6 +/- 2.1 to -63.1 +/- 1.8 mV). In the presence of flecainide, Vmax further decreased by 20.2 +/- 2.6%, and Vh shifted from -63.1 +/- 1.8 to -65.0 +/- 1.5 mV. Comparison with the control unstretched fibers showed that flecainide significantly decreased Vmax by 34.0 +/- 2.7%, reduced the resting membrane potential by 3 +/- 1 mV, decreased Eov by 4 +/- 1 mV, and shifted Vh from -60.6 +/- 2.1 to -65.0 +/- 1.5 mV, while the APD50 and ERP did not change. In conclusion, the reduction of Vmax in the presence of flecainide was much greater in the stretched atrial muscle fibers than in the unstretched fibers, because the Vmax-resting potential relationship was shifted towards more negative potentials by both flecainide and stretching. These results suggest that flecainide exerts a stronger antiarrhythmic action on stretched atrial muscle fibers than on normal fibers.
- Published
- 1993
200. Optical and Electrical Characterization of Hydrogen-Plasma-Damaged Silicon Surface Structures and Its Impact on In-line Monitoring
- Author
-
Tetsuya Tatsumi, Koji Eriguchi, Yoshinori Nakakubo, Yoshinori Takao, Kouichi Ono, Asahiko Matsuda, and Masanaga Fukasawa
- Subjects
Materials science ,Silicon ,Band gap ,General Engineering ,Analytical chemistry ,General Physics and Astronomy ,chemistry.chemical_element ,Plasma ,Photon energy ,Characterization (materials science) ,chemistry ,Crystalline silicon ,Layer (electronics) ,Line (formation) - Abstract
Si surface damage induced by H2 plasmas was studied in detail by optical and electrical analyses. Spectroscopic ellipsometry (SE) revealed a decrease in the pseudo-extinction coefficient in the region of photon energy higher than ∼3.4 eV upon H2-plasma exposure, which is attributed to the disordering of crystalline silicon (c-Si). The increase in in the lower energy region indicates the presence of trap sites for photogenerated carriers in the energy band gap in the E–k space of Si. The current–voltage (I–V) measurement of metal-contacted structures was performed, revealing the following characteristic structures: thinner surface (SiO2) and thicker interface (SiO2:c-Si) layers on the Si substrate in the case of H2-plasma exposure than those with Ar- and/or O2-plasma exposure. The structure assigned on the basis of both SE and I–V was further analyzed by a layer-by-layer wet-etching technique focusing on the removability of SiO2 and its etch rate. The residual damage-layer thickness for the H2-plasma process was thicker (∼10 nm) than those for other plasma processes (2/Si) optical model should be revised for in-line monitoring of H2-plasma damage.
- Published
- 2010
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