341 research outputs found

    Factors Affecting Plunge Grinding Force

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    Grinding force has a close relation to grinding inputs such as grinding wheel, work material, interference condition, grinding speed, grinding fluid and machine condition, and therefore varies widely with grinding inputs. On the other hand, grinding force affects significantly grinding outputs which are efficiency and quality evaluated with surface roughness, accuracy, surface integrity and so on. It is important to make clear the relations between grinding inputs and grinding force in order to control grinding outputs. In this paper, from the above point of view, the relations between grinding inputs and grinding force are experimentally investigated. It is pointed out that the normal grinding force, the tangential grinding force and its ratio are determined by the product of speed ratio of work speed to wheel speed and setting depth of cut as for interference conditions, and by the product of square of dressing feed and cutting depth of. dresser as for dressing conditions. Furthermore as for characteristics of work materials, the normal grinding force has a close relation to the yield stress, and the force ratio is related to the elongation of work material

    The Effect of Electrode Polarity on Electrical Discharge Machining Performance in Water

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    Practical utilization of ram type electrical discharge machining in uninflammable fluid has been expected in place of inflammable kerosine type fluid for unmanned operation in a workshop. The electrical discharge machining performance in deionized water is experimentally investigated on the basis of the analysis of the crater generated by a single pulse discharge. The experimental analysis makes it clear that the electrical discharge machining performance in deionized water is greatly affected by the electrode polarity. The metal removal rate in the normal polarity machining is higher than that in reverse polarity machining, while the electrode wear rate in the normal polarity machining is greater than that in reverse polarity machining. Therefore the electrode polarity should be properly selected according to the purpose of machining

    Fundamental Study on Electrical Discharge Machining

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    The generation mechanism of crater in electrical discharge machining is analyzed with a single pulse discharge device for alloy tool steel, black alumina ceramics, cermet and cemented carbide, investigating the gap voltage, the discharge current, the shape of crater, the wear of electrode and so on. The experimental analysis makes it clear that the shape of crater has a characteristic feature for the kind of workpiece. The shape of electrode, which changes with the wear by an electric spark, has a significant effect on the shape of crater. The diameter and the depth of crater have a close relation to the discharge energy for alloy tool steel, black alumina ceramics and cermet, while those for cemented carbide are related to the discharge current. The shape factor which is the ratio of the depth to the diameter of crater is different for the work material

    Evaluation of Creatine Kinase, Lactate Dehydrogenase, and Amylase Concentrations in Umbilical Blood of Preterm Infants after Long-Term Tocolysis

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    Creatine kinase (CK), lactate dehydrogenase (LDH), and amylase levels of preterm infants following long-term tocolysis in pregnant women are limited. The objective of this study was to determine if the tocolytic therapy affects CK, LDH, and amylase levels in the umbilical blood. This study included 215 preterm infants born to women treated with and without ritodrine hydrochloride. CK, LDH, and amylase levels in the umbilical blood at delivery were determined. Infants were divided according to the ritodrine tocolysis, as follows: Group A (n=91), not exposed to ritodrine; Group B (n=44), IV ritodrine for <1 week; Group C (n=80), IV ritodrine for ≥1 week. The CK concentration in cord blood of Group C (198.8±14.2 IU/L) was significantly higher in comparison with Group A (155.0±7.3 IU/L, P<0.05). There was no significant difference in LDH and amylase levels in the three groups. The CK significantly correlated with gestational age (r=0.42, P<0.01) and birth weight (r=0.38, P<0.01). LDH and amylase levels did not change with gestational age nor birth weight. In conclusion, long-term ritodrine tocolysis leads to increased umbilical blood CK level

    SUCCESSFULLY COMPLETE EXCISION OF A HUGE SACROCOCCYGEAL TERATOMA: A CASE REPORT

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    A female infant was born with a huge sacrococcygeal teratoma (SCT) at 36 weeks of gestation with a weight of 4546g (combined weight of the infant and tumor). The patient's mother developed polyhydramnios and cesarean section was performed at 36 weeks of gestation. MRI showed Altman classification type Ⅱ SCT. We performed abdominoperineal resection at 3 days after birth. The mass was completely excised, and the size and the weight of the mass were 18×12×15cm and 1100g (Weight of SCT against body weight; 393 g/kg), respectively. The pathological findings revealed a grade Ⅱ immature teratoma with no malignant elements such as yolk sac tumor. The patient was discharged at 45 days after birth with fecal continence, but neurogenic bladder dysfunction. At 9 months after surgery, the patient was doing well with no evidence of tumor recurrence, and AFP levels had returned to normal values

    Direct Patterning of Ceramic Circuit Board with Q-Switched Nd:YAG Laser

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    Direct patterning of copper coated ceramic circuit board is experimentally investigated with Q-switched Nd:YAG laser in order to shorten the time of the trial manufacture of electronic circuit board and to adapt the flexible design change. It is pointed out that the fast direct patterning the speed of which reaches about 100 mm/s is possible if the repetition frequency and the average power are selected properly. Furthermore cutting off and/or drilling of ceramic board are also possible under the condition that the repetition frequency is less than 3kHz. This technique makes it possible the mask1ess patterning of ceramic circuit board which has been widely used recently in place of conventional glass-epoxy or phenolic resin circuit board, and it leads to the shorter time limit of delivery as compared with the conventional end-milling method

    Determination of ADAMTS13 and Its Clinical Significance for ADAMTS13 Supplementation Therapy to Improve the Survival of Patients with Decompensated Liver Cirrhosis

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    The liver plays a central role in hemostasis by synthesizing clotting factors, coagulation inhibitors, and fibrinolytic proteins. Liver cirrhosis (LC), therefore, impacts on both primary and secondary hemostatic mechanisms. ADAMTS13 is a metalloproteinase, produced exclusively in hepatic stellate cells, and specifically cleaves unusually large von Willebrand factor multimers (UL-VWFM). Deficiency of ADAMTS13 results in accumulation of UL-VWFM, which induces platelet clumping or thrombi under high shear stress, followed by sinusoidal microcirculatory disturbances and subsequent progression of liver injuries, eventually leading to multiorgan failure. The marked imbalance between decreased ADAMTS13 activity (ADAMTS13 : AC) and increased production of UL-VWFM indicating a high-risk state of platelet microthrombi formation was closely related to functional liver capacity, hepatic encephalopathy, hepatorenal syndrome, and intractable ascites in advanced LC. Some end-stage LC patients with extremely low ADAMTS13 : AC and its IgG inhibitor may reflect conditions similar to thrombotic thrombocytopenic purpura (TTP) or may reflect “subclinical TTP.” Hence, cirrhotic patients with severe to moderate deficiency of ADAMTS13 : AC may be candidates for FFP infusion as a source of ADAMTS13 or for recombinant ADAMTS13 supplementation. Such treatments may improve the survival of patients with decompensated LC

    RETROPERITONEAL SCHWANNOMA : A CASE REPORT AND REVIEW OF THE LITERATURE

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    Reported herein is a rare case of retroperitoneal schwannoma in a patient without von Recklinghausen's disease. This patient was free of symptoms, and the tumor was found by chance during a periodical physical examination. Complete excision of the tumor was performed, and as of this writing, 36 months after the operation, the patient is free of the disease. In addition, a review was carried out on the 121 cases of retroperitoneal schwannoma reported in the Japanese literature from 1981 to 1992. In this series, malignant tumors were seen in 26.4% of all cases, and when this tumor was found in association with von Recklinghausen's disease, the malignancy rate increased to 52.9%. Thirty seven percent of the patients with malignant tumors had died at the time of writing of their case report, and their mean survival period was 18 months after the first surgical treatment. All the patients with benign tumors underwent complete resection and had a good prognosis

    重症慢性肝疾患における高γク口ブリン血症の意義 : とくに血清グ口プリン/IgG とICG除去能との相聞に関連して

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    BACKGROUND/AIMS:Although hyperglobulinemia is frequently detected in severe chronic liver diseases (CLD) such as liver cirrhosis (LC), the mechanism for this is still uncertain. Hyperglobulinemia may represent a functional aspect of the liver.METHODOLOGY: The correlation between serum globulin (GLB) level and each of various liver function tests including the indocyanine green (ICG) retention rate at 15 min (ICGR15) was studied using 146 patients with liver dysfunction. The correlations among GLB, IgG and ICGR15 were also studied in other 32 patients with LC, in whom the glycosylation pattern of IgG was determined by enzyme-linked immunosorbent assay to detect terminal galactose (Gal) and neuraminic acid (NA) using biotinylated lectins.RESULTS:GLB level was predominantly correlated with ICGR15 (r = 0.449) among various liver function tests in 146 patients with liver dysfunction. In the 32 patients with LC, strong positive correlations between GLB and IgG (r = 0.875), between GLB and ICGR15 (r = 0.435), and between IgG and ICGR15 (r = 0.557) were evident. The glycosylation pattern of IgG showed that the proportions of both Gal and NA were inversely correlated with serum IgG levels (r = -0.516 and -0.390, respectively) in these patients. Significant decreases of the proportions were found in patients with IgG elevation (> 20 g/L, n = 13).CONCLUSIONS:The correlation between GLB and ICGR15 suggested that hyperglobulinemia is related to a common dysfunction estimated by ICG clearance, which represents mainly the liver's blood flow and removal capacity. The removal of immunoglobulins by the liver may be impaired in patients with severe liver dysfunction because the liver is a major catabolic site for immunoglobulins. The glycation pattern suggested that the proportions of asialo IgG and agalactosyl IgG were increased in the LC patients with IgG elevation possibly by deficient receptor-mediated removal in the liver. Although further investigations will be needed, hyperglobulinemia could be predictive for a certain impaired hepatic function estimated by ICG clearance in severe CLD such as LC.博士(医学)・乙第1301号・平成24年7月26日Hepato Gastroenterology © 200

    ヒト肝細胞癌においてherpesvirus entry mediatorの発現がもたらす影響

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    BACKGROUND: Herpes virus entry mediator (HVEM), also known as tumour necrosis factor receptor (TNFR) superfamily 14, regulates a variety of physiological and pathological responses in both innate and acquired immunity. Although HVEM is also suggested to be a critical regulator in tumours, actual roles in human cancer are largely unknown. This study aimed to clarify clinical importance of HVEM in human hepatocellular carcinoma (HCC). PATIENTS AND METHODS: We studied HVEM expression in 150 HCC patients to explore its clinical relevance, and we examined tumour infiltrating T cells and local immune status of them. RESULTS: HVEM was expressed in HCC cells, while no or only limited expression was observed in normal tissues in the liver. Tumour HVEM expression was significantly correlated with age, serum protein induced by vitamin K absence or antagonist-II (PIVKA-II) level, vascular invasion and tumour node metastasis (TNM) stage. Furthermore, tumour HVEM expression significantly correlated with postoperative recurrence and survival. Importantly, multivariate analysis indicated that the HVEM status had an independent prognostic value. Furthermore, HVEM status was inversely correlated with tumour-infiltrating CD4(+), CD8(+) and CD45RO(+) lymphocytes. In addition, it was also associated with reduced expression of perforin, granzyme B and interferon-γ (IFN-γ). Taken together, tumour-expressing HVEM plays a functionally important role in HCC. CONCLUSION: Tumour-expressing HVEM plays a critical role in human HCC, possibly through regulating immune evasion. Therefore, targeting HVEM may be a novel promising therapeutic strategy for HCC.博士(医学)・乙第1359号・平成27年5月28日Copyright © 2014 Elsevier Ltd
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