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Costa P, Terini R, Freitas M, Watanabe E. SU-GG-E-03: Current Status of Medical Physics Undergraduation Courses in Brazil. Med Phys 2010. [DOI: 10.1118/1.3468033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Shojima M, Nemoto S, Morita A, Miyata T, Namba K, Tanaka Y, Watanabe E. Protected endovascular revascularization of subacute and chronic total occlusion of the internal carotid artery. AJNR Am J Neuroradiol 2010; 31:481-6. [PMID: 19850764 DOI: 10.3174/ajnr.a1843] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE The natural course of symptomatic carotid artery occlusion with hemodynamic impairment is poor. Surgical revascularization may improve the outcome; however, its efficacy has not been established yet. The goal of this study was to characterize the technical and clinical outcomes following endovascular recanalization of the ICA under cerebral circulatory protection. MATERIALS AND METHODS Endovascular recanalization was attempted in 8 patients with symptomatic ICA occlusions. The duration of the occlusion ranged from 7 days to 7 months (mean, 2.5 months), and the mean length of the occlusion was 95 mm. Cerebral hemodynamics ipsilateral to the side of the occlusion were severely impaired in all patients. The endovascular procedure was performed under total cerebral circulatory protection, beginning with proximal protection with a subsequent switch to distal protection after successful guidewire passage. RESULTS The occlusion was recanalized successfully in 7 of 8 patients (88%), resulting in improvement of ipsilateral cerebral hemodynamics without symptomatic stroke. Small asymptomatic ischemic lesions were detected in 6 of 8 patients (75%) on DWI, and 1 patient developed a mild groin hematoma. Ischemic episodes did not recur during the mean follow-up period of 19 months. However, 1 patient experienced asymptomatic reocclusion, which was re-treated successfully without complications, while another patient developed mild retinal hemorrhage at 3 months after the procedure due to the combination of antiplatelet and anticoagulant therapy. CONCLUSIONS Endovascular revascularization of an ICA occlusion is feasible and well-tolerated in patients with subacute or chronic total occlusion of the ICA.
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Miyoshi T, Tanaka I, Tsuyuhara T, Watanabe E, Aizawa T, Kimura K, Watanabe Y. Fouling potentials of polysaccharides in membrane bioreactors (MBRs) assessed by lectin affinity chromatography. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2010; 61:1787-1792. [PMID: 20371937 DOI: 10.2166/wst.2010.113] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
In this study, the fouling potentials of polysaccharides contained in mixed liquor suspension in a membrane bioreactor (MBR) treating municipal wastewater were investigated using lectin affinity chromatography. This investigation was carried out with different membranes to assess the effects of membrane materials on fouling potentials of polysaccharides. In lectin affinity chromatography, some polysaccharides with high affinity to the lectin in the column can be retained in the column. The fouling potentials of the retained polysaccharides were evaluated by dead-end filtration test. Degree of reduction in fouling potential differed considerably when different lectins were used in affinity chromatography indicating that fouling potentials of polysaccharide differed depending on types of polysaccharide. Trends in the reduction of fouling potential were different depending on membrane materials. Characteristics of the organic matter associated with polysaccharides removed by lectins were investigated by means of excitation-emission matrices (EEM). The results of EEM analysis indicate that the characteristics of the organic matter eluted from different lectins were different as long as elution reagents for the lectin were different. Characteristics of the organic matter eluted from the lectins which have the same elution reagent were similar in terms of shapes of EEM fluorescence spectra. However, the trends in reduction of fouling potentials could not be explained by the characteristics of organic matter assessed by EEM analysis. On the basis of the results obtained in this study, it can be concluded that characteristics of membrane and structures or properties of sugar chain would play an important role in determining fouling potentials.
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Moriyama S, Tsuya D, Watanabe E, Uji S, Shimizu M, Mori T, Yamaguchi T, Ishibashi K. Coupled quantum dots in a graphene-based two-dimensional semimetal. NANO LETTERS 2009; 9:2891-2896. [PMID: 19719107 DOI: 10.1021/nl9011535] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We present an experimental demonstration of a graphene-based double quantum dot system, which exhibits single-electron transport of two lateral quantum dots coupled in series. Low-temperature transport measurements revealed honeycomb charge stability diagrams with a varied (from weak to strong) interdot tunnel-coupling regime, and we have extracted the relevant parameters associated with the double quantum dot system. These results are important for the realization of integrated quantum circuits in graphene-based electronics.
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Conzen K, Upadhya G, Jia J, Csontos K, Watanabe E, Hotchkiss R, Chapman W, Anderson C. QS188. Transplantation of the Steatotic Liver Results in Significant Upregulation of Proapoptotic BCL-2 Proteins. J Surg Res 2009. [DOI: 10.1016/j.jss.2008.11.488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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81
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Ito W, Takeda M, Kayaba H, Ueki S, Sato K, Honda K, Kume M, Ishibashi K, Kobayashi N, Kagaya H, Fukui R, Watanabe E, Sakurada N, Tomita N, Chihara J. Clinical Evaluation after a Notification Policy of Linezolid Use: A Case Series of 22 Patients. J Chemother 2009; 21:52-7. [DOI: 10.1179/joc.2009.21.1.52] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Kim YS, Eun H, Cho HS, Kim KS, Watanabe E, Baba K, Katase T. The characterization of PCDDs, PCDFs and coplanar PCBs during the past 50 years in Gwangyang Bay, South Korea. JOURNAL OF HAZARDOUS MATERIALS 2008; 154:756-765. [PMID: 18063300 DOI: 10.1016/j.jhazmat.2007.10.088] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Revised: 10/24/2007] [Accepted: 10/24/2007] [Indexed: 05/25/2023]
Abstract
The PCDD/DFs and coplanar PCBs (co-PCBs) in sediment samples from Gwangyang Bay in South Korea was investigated. The total concentration of dioxins and their toxic equivalent quantity (TEQ; calculated with the WHO 2005 Toxic Equivalency Factors) value in the surface sediment of the outer site (261 pg g(-1) TOC, 4.4 pg-TEQ g(-1)) were 3-fold higher than the inner site (90 pg g(-1) TOC, 1.1 pg-TEQ g(-1)) in the Bay. The dioxin in the sediment samples was found to come from a mixture of the impurities of pentachlorophenol (PCP), chloronitrofen (CNP) and combustion based on the result of hierarchical cluster analysis (HCA). These dioxin sources have been influenced by the characterization associated with this region which was both an agricultural-centered and industrial-centered area. According to principal component analysis (PCA) related to the Kow values for the congener-specific composition of co-PCBs in the sediment core, the Kanechlor (KC)-500 and the atmospheric deposition were identified as the possible sources. The maximum burden in the sediment core was 1.3 kg for 1967-1974 and the total burdens of PCDD/DFs and co-PCBs in the sediment core were estimated to be 6.6 kg during the past 50 years. The cumulative burdens of dioxin are still increasing in Gwangyang Bay.
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do Nascimento C, Barbosa R, Issa J, Watanabe E, Ito I, Albuquerque R. Bacterial leakage along the implant–abutment interface of premachined or cast components. Int J Oral Maxillofac Surg 2008; 37:177-80. [DOI: 10.1016/j.ijom.2007.07.026] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2007] [Revised: 06/27/2007] [Accepted: 07/17/2007] [Indexed: 11/17/2022]
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Watanabe E, Agostinho AM, Matsumoto W, Ito IY. Dental unit water: bacterial decontamination of old and new dental units by flushing water. Int J Dent Hyg 2008; 6:56-62. [DOI: 10.1111/j.1601-5037.2007.00278.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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85
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Kurihara R, Watanabe E, Ueda Y, Kakuno A, Fujii K, Shiraishi F, Hashimoto S. Estrogenic activity in sediments contaminated by nonylphenol in Tokyo Bay (Japan) evaluated by vitellogenin induction in male mummichogs (Fundulus heteroclitus). MARINE POLLUTION BULLETIN 2007; 54:1315-20. [PMID: 17673263 DOI: 10.1016/j.marpolbul.2007.06.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2006] [Revised: 05/30/2007] [Accepted: 06/01/2007] [Indexed: 05/04/2023]
Abstract
Estrogenic activity was determined in sediments collected from Tokyo Bay. Sampling was performed at five stations including the site near the sewage treatment plant. The most estrogenic sediment collected near the sewage treatment plant was fractionated into ten fractions using normal-phase high-performance liquid chromatography. Chemical analysis was carried out for each fraction and nonylphenol (NP, 20,700ngg(-1)drywt) was detected at a higher concentration than estron (2.39ngg(-1)drywt) and 17beta-estradiol (<0.7ng g(-1)dry wt). Furthermore, each fraction was administered to male mummichogs (Fundulus heteroclitus), and vitellogenin (Vtg) was measured after two weeks. The induction of Vtg was observed; this estrogenic potency could be attributed to the NP content in this fraction. This is the first report to suggest that the high NP concentration in the sediments from Tokyo Bay has the potential to induce Vtg in wild fish.
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Park H, Togo F, Watanabe E, Yasunaga A, Park S, Shephard RJ, Aoyagi Y. Relationship of bone health to yearlong physical activity in older Japanese adults: cross-sectional data from the Nakanojo Study. Osteoporos Int 2007; 18:285-93. [PMID: 17061150 DOI: 10.1007/s00198-006-0237-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2006] [Accepted: 09/22/2006] [Indexed: 02/04/2023]
Abstract
INTRODUCTION We determined associations between bone health and the quantity and quality of habitual physical activity in a cohort of 172 free-living Japanese aged 65-83 years (76 men, 96 women). METHODS The number of steps taken and the intensity of physical activity were measured every 4 s throughout each 24-h period for 1 year, using a specially adapted accelerometer that distinguished up to 11 levels of physical activity (expressed in metabolic equivalents, METs). At the end of the year, a quantitative ultrasonic technique assessed each participant's osteosonic index (OSI, reflecting bone stiffness in the calcaneus). RESULTS The data were significantly described by linear and exponential regression models which showed that in both sexes the OSI score increased with increasing daily physical activity, up to the observed maximum values of approximately 14,000 steps/day and 50 min/day at an intensity >3 METs. However, when data were categorized into quartiles of physical activity, OSI scores were not significantly greater in persons exceeding recommended minimum standards of habitual physical activity (corresponding to counts of around 6,900 and 6,800 steps/day and durations >3 METs of around 18 and 16 min/day in men and women, respectively). All who met such criteria (with the exception of a few women) had OSI scores above the threshold for a clinical diagnosis of osteoporosis. Multivariate-adjusted logistic regression analyses predicted that men and especially women who engaged in <6,800 steps/day and <16 min/day of moderate-intensity physical activity were, respectively, 4.9-8.4 and 2.2-3.5 times more likely to sustain fractures than those participating in >8,200 steps/day and >25 min/day of activity >3 METs. CONCLUSION Causation cannot be inferred from a cross-sectional study. Nevertheless, we suggest that from the viewpoint of bone health, elderly people should be encouraged to engage in low- and moderate-intensity habitual physical activity, taking >7,000 steps/day with a duration >15 min/day at >3 METs.
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Yamaguchi T, Arafune T, Sakuma I, Watanabe E, Shibata N, Honjo H, Kodama I, Kamiya K. Analysis of QT Interval Prolongation With Heart Failure by Simulation of Repolarization Process. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2007; 2005:7309-12. [PMID: 17281968 DOI: 10.1109/iembs.2005.1616199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
It has been postulated that action potential duration (APD) is prolonged and I<inf>Ks</inf>, a slow component of delayed rectifier potassium current, decreases in heart failure. We have reported that QT interval is prolonged and expression weight of KCNE1, coding I<inf>Ks</inf>channel, increases in patients with heart failure. Since it is known that increase in KCNE1 increases the maximum conductance of I<inf>Ks</inf>channel, the mechanism of APD prolongation is not explained by over expression of KCNE1. In this study, we construct a cardiac membrane action potential simulation model based on the experimental data from Xenopus oocytes expressed KCNQ1 and KCNE1 to investigate the relationship between increase in KCNE1 and APD. In addition, we investigated effect of reduction in Ca<sup>2+</sup>-independent transient outward potassium current (I<inf>to</inf>) on APD in heart failure. In simulation, APD at 5ng KCNE1 was 180.96ms, which was 4.63% longer than that at 1ng KCNE1 (APD=172.96ms) and 55.9% longer than that at 0.2ng KCNE1 (APD=110.96ms. In the cases of KCNQ1 alone and 0.2ng KCNE1 coinjected, APD shortened as density of I<inf>to</inf>decreased, and APD prolonged as density of I<inf>to</inf>decreased in other cases. This study shows that increase in KCNE1 expression level makes maximum conductance of I<inf>Ks</inf>channel increase and I<inf>Ks</inf>channel open slowly and conductance of I<inf>Ks</inf>channel decrease according to the APD time scale. Therefore increasing the KCNE1 expression level may prolong APD with this mechanism. This method of constructing a simulation model based on experiments helps to explain the relationship between potassium currents and QT interval prolongation.
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Kanda M, Ohto-Ozaki H, Kuroiwa K, Tominaga S, Watanabe E, Iwahana H. Elevation of ST2 protein levels in cerebrospinal fluid following subarachnoid hemorrhage. Acta Neurol Scand 2006; 113:327-33. [PMID: 16629769 DOI: 10.1111/j.1600-0404.2006.00587.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To study the mode of appearance of ST2 in cerebrospinal fluid (CSF) after subarachnoid hemorrhage (SAH). MATERIALS AND METHODS Immunoprecipitation and subsequent immunoblotting were performed to reveal the existence of ST2 in CSF after SAH. CSF samples from 21 patients were analyzed for ST2 using an enzyme-linked immunosorbent assay system. The ST2 levels were compared between serum and CSF after SAH. The ST2 levels in CSF were measured in six patients operated with other than SAH. RESULTS ST2 was secreted into CSF after SAH. The concentration of ST2 was the highest in the samples of the first post-operative day and declined thereafter. The patients operated with other than SAH did not show the elevation of ST2 in CSF. CONCLUSIONS This study revealed the presence of ST2 in CSF for the first time and suggested a possibility that ST2 is related to the inflammatory reaction in the central nervous system after SAH.
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Osawa H, Kita H, Ohnishi H, Hoshino H, Mutoh H, Ishino Y, Watanabe E, Satoh K, Sugano K. Helicobacter pylori eradication induces marked increase in H+/K+-adenosine triphosphatase expression without altering parietal cell number in human gastric mucosa. Gut 2006; 55:152-7. [PMID: 15872000 PMCID: PMC1856523 DOI: 10.1136/gut.2005.066464] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND AIMS Gastric acid secretion is downregulated by Helicobacter pylori infection and upregulated after its eradication, but the mechanisms are still unclear. We examined the effects of H pylori eradication on the number of parietal cells and on expression of molecules functioning in acid secretion in the human gastric mucosa. METHODS We enrolled 111 consecutive men with chronic gastritis induced by H pylori. Biopsy specimens were endoscopically obtained before and 12 weeks after successful eradication of H pylori and parietal cell numbers were counted. mRNA expression levels of H+/K+-adenosine triphosphatase (H+/K+-ATPase), anion exchanger 2, M3 muscarinic receptor, intrinsic factor, and interleukin 1beta were determined with a real time reverse transcriptase-polymerase chain reaction method. The severity of gastric atrophy was evaluated using the serum pepsinogen I/II ratio. RESULTS No significant difference was observed in parietal cell numbers before and after H pylori eradication. Median mRNA expression levels of H+/K+-ATPase in the gastric mucosa increased 250-fold after H pylori eradication accompanied by attenuation of interleukin 1beta. A large increase in H+/K+-ATPase expression was observed even in patients with severe atrophic gastritis. In contrast, fold increases in mRNA expression levels, including intrinsic factor, anion exchanger 2, and M3 muscarinic receptor, after eradication therapy, were limited to 1.4, 2.3, and 2.5 times, respectively. CONCLUSIONS In the absence of alteration of parietal cell number, gastric H+/K+-ATPase mRNA expression was markedly restored after successful H pylori eradication, suggesting a central role for the restoration of H+/K+-ATPase expression in gastric acid secretion recovery after H pylori eradication.
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Ikenaka Y, Eun H, Watanabe E, Miyabara Y. Sources, distribution, and inflow pattern of dioxins in the bottom sediment of Lake Suwa, Japan. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2005; 75:915-21. [PMID: 16400579 DOI: 10.1007/s00128-005-0837-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2005] [Accepted: 08/17/2005] [Indexed: 05/06/2023]
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Watanabe I, Kurtz KS, Watanabe E, Yamada M, Yoshida N, Miller AW. Multi-unit fixed partial denture for a bilateral cleft palate patient: a clinical report. J Oral Rehabil 2005; 32:620-2. [PMID: 16011642 DOI: 10.1111/j.1365-2842.2005.01468.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Patients with cleft palates eventually require definitive fixed or removable dental prostheses after the maintenance of arch alignment and occlusal relationship during adolescence. This case report presents application of a resin composite veneered fixed partial denture utilized as a definitive prosthesis for a bilateral cleft palate patient after stable occlusion had been established orthodontically. The composite veneered long span fixed partial denture provides adequate aesthetics and function.
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Matsuda K, Hirasawa H, Oda S, Shiga H, Nakamura M, Watanabe E. Crit Care 2005; 9:P372. [DOI: 10.1186/cc3435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Nakamura M, Hirasawa H, Oda S, Shiga H, Matsuda K, Watanabe E. Crit Care 2005; 9:P349. [DOI: 10.1186/cc3412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Prelog V, Philbin E, Watanabe E, Wilhelm M. Untersuchungen über asymmetrische Synthesen VIII. Optisch aktive Hilfsalkohole mit einem asymmetrischen Kohlenstoff-Atom. Helv Chim Acta 2004. [DOI: 10.1002/hlca.19560390411] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Kobayashi T, Kajiwara M, Wahyuni M, Hamada-Sato N, Imada C, Watanabe E. Effect of culture conditions on lactic acid production of Tetragenococcus species. J Appl Microbiol 2004; 96:1215-21. [PMID: 15139912 DOI: 10.1111/j.1365-2672.2004.02267.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
AIMS To investigate the effects of the salt concentration, incubation temperature and initial pH of the medium on the fermentative ability of the halophilic lactic acid bacteria, Tetragenococcus muriaticus and T. halophilus. METHOD AND RESULTS The growth, lactic acid production and pH reduction ability of five strains of T. muriaticus and T. halophilus in MRS broth medium under various culture conditions such as salt concentration (3, 7, 15 and 23% NaCl), temperature (20, 30 and 40 degrees C), and initial medium pH (5.8, 6.5 and 7.5) were investigated. Those of T. halophilus were seriously affected by a high salinity (23% NaCl); in contrast, those of T. muriaticus were affected by a low initial pH (5.8). CONCLUSIONS The results indicate that high saline concentrations and low pH values have significant impact on the growth, lactic acid production and pH reduction ability of T. halophilus and T. muriaticus, respectively. SIGNIFICANCE AND IMPACT OF THE STUDY This study appears to be important in biopreservation during the manufacture of fermented food products. Both T. muriaticus and T. halophilus may support each other in reducing pH in hypersaline or low pH environment. To our knowledge, this is the first report on the fermentation ability of T. muriaticus.
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Watanabe I, Baba N, Watanabe E, Atsuta M, Okabe T. Effect of heat treatments on machinability of gold alloy with age-hardenability at intraoral temperature. J Dent 2004; 32:9-15. [PMID: 14659713 DOI: 10.1016/s0300-5712(03)00117-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
OBJECTIVE This study investigated the effect of heat treatment on the machinability of heat-treated cast gold alloy with age-hardenability at intraoral temperature using a handpiece engine with SiC wheels and an air-turbine handpiece with carbide burs and diamond points. METHODS Cast gold alloy specimens underwent various heat treatments [As-cast (AC); Solution treatment (ST); High-temperature aging (HA), Intraoral aging (IA)] before machinability testing. The machinability test was conducted at a constant machining force of 0.784N. The three circumferential speeds used for the handpiece engine were 500, 1,000 and 1,500 m/min. The machinability index (M-index) was determined as the amount of metal removed by machining (volume loss, mm(3)). The results were analyzed by ANOVA and Scheffé's test. RESULTS When an air-turbine handpiece was used, there was no difference in the M-index of the gold alloy among the heat treatments. The air-turbine carbide burs showed significantly (p<0.05) higher M-indexes than the diamond points after any heat treatments. With the SiC wheels, increasing the circumferential speed increased the M-index values for each heat treatment. The specimens heat-treated with AC, HA and IA had similar M-indexes at the lower speeds (500 and 1,000 m/min). The ST specimens exhibited the lowest M-index at the lower speeds. However, at the highest speed (1,500 m/min), there were no significant differences in the M-indexes among the heat treatments except for HA, which showed the highest M-index. CONCLUSION There was no effect of heat treatment on the machinability of the gold alloy using the air-turbine handpiece. The heat treatments had a small effect on the M-index of the gold alloy machined with a SiC wheel for a handpiece engine.
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Watanabe E, Suzuki M, Nagata K, Kaneeda T, Harada Y, Utsumi M, Mori A, Moriya H. Oxidation-induced dynamic changes in morphology reflected on freeze-fractured surface of gamma-irradiated ultra-high molecular weight polyethylene components. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 2002; 62:540-9. [PMID: 12221702 DOI: 10.1002/jbm.10357] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Oxidative degradation of ultra-high molecular weight polyethylene (UHMWPE) attributed to sterilization by gamma-radiation in the presence of air has been cited as one of the major causes of premature wear in total joint arthroplasty. For example, in retrieved UHMWPE tibial bearings, not only adhesive and abrasive wear, but also fatigue wear characterized by delamination and fracture is frequently observed. In this study, we examined the effects of gamma radiation on the microstructural morphology of UHMWPE tibial bearings, and propose a severe fatigue wear mechanism. Scanning electron microscopic observations were conducted on freeze-fractured surface of retrieved UHMWPE components that had been sterilized with gamma radiation in air before implantation, unused components that had been stored on the shelf for several years (5-11) after sterilization, and disc specimens given an accelerated aging protocol after gamma radiation. Scanning electron microscopic observations showed that the freeze-fractured surface of these components had a double layer, which was bordered below the surface. A closer observation of the subsurface layer below the border revealed an extremely rough and porous honeycomb-like structure. Fourier transform infrared analysis demonstrated that the honeycomb-like region in the subsurface had a high oxidation level. The internal morphology of oxidized UHMWPE was classified into four categories based on the level of the oxidation. According to these results, the morphological changes with oxidative degradation of gamma-irradiated UHMWPEs in the presence of air could consistently be explained as the result of major chemical and physical changes such as increased crystallinity, elevated density, and reduced mechanical strength. We relate the morphological changes caused by oxidative degradation in the subsurface to the location of the origin of fatigue wear in total knee joints.
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Kitagawa T, Abe M, Kyogoku Y, Ogoshi H, Watanabe E, Yoshida Z. Resonance Raman spectra of metallooctaethylporphyrins. Low frequency vibrations of porphyrin and iron-axial ligand stretching modes. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100552a012] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Ogoshi H, Watanabe E, Yoshida Z, Kincaid J, Nakamoto K. Infrared spectra of metal complexes of octaethylchlorine analogs of chlorophyll and heme d. Inorg Chem 2002. [DOI: 10.1021/ic50148a029] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Mayanagi Y, Watanabe E, Nagahori Y, Nankai M. Psychiatric and neuropsychological problems in epilepsy surgery: analysis of 100 cases that underwent surgery. Epilepsia 2002; 42 Suppl 6:19-23. [PMID: 11902315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
PURPOSE For the past 20 years (1978-1997), a series of 100 cases of uncontrolled epilepsy had surgery in our department under the stated standard for surgical indications and were followed up for 2-22 years after surgery. METHODS We evaluated 70 cases of temporal lobectomy, 20 cases of neocortical focal resection, and 10 cases of corpus callosotomy. RESULTS Analysis of postoperative seizure control showed that 78 cases were class 1 or 2 (no or rare seizures), 14 cases were class 3 (worthwhile improvement), and eight cases were class 4 (no improvement). As generally accepted, temporal lobectomy was the most effective operative procedure, yielding excellent or good results in 87% of the 70 cases so treated. Among the nine cases in whom various psychiatric symptoms developed after surgery, four cases showed neurotic and five cases psychotic symptoms. Patients with psychosis had delusions of various types as a core symptom, combined with other symptoms such as anxiety, irritability, aggression, and depressive state. In two patients with psychosis who had episodes of delusions in the interictal phase before surgery, the symptoms were extremely resistant. The full IQ score of the Wechsler Adult Intelligence Scale-Revised (WAIS-R) was increased after temporal lobectomy in 75% of the cases (p < 0.01; n = 44). The general MQ score in 31 cases, however, showed a 50:50 split between increase and decrease postoperatively. In correlation with the dominance of language by the Wada test, the general MQ score in the 15 cases of nondominant temporal lobe resection showed a significant increase (p < 0.05); whereas the MQ in the 16 cases of dominant-side operation did not change. CONCLUSIONS Our new test, in which hippocampal stimulation and supraspan learning are combined, seems to be efficient for estimating the postoperative outcome of memory function.
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