150 research outputs found

    Superconducting Properties and Microstructure in Dilute Copper Alloys Containing Small Amounts of V_3Ga Particles(Metallurgy)

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    The superconducting properties (T_c and J_c) were investigated by the resistivity measurement, and the structure was observed by a transmission electron microscopy in the dilute copper alloys containing small amounts of V_3Ga particles prepared by quenching from the liquid state and aging. No superconductivity could be observed at 4.2 K in as-quenched and/or in overaged samples. The highest T_ (=12.5 K), T_ (=9.6 K), and J_c (=525 A/cm^2) were obtained by aging at 700℃ for 96 h and corresponded with the structure of fine V_3Ga precipitates dispersed homogeneously in the copper matrix. Therefore, it is concluded that superconductivity in these alloys results from the superconducting path due to the proximity effect of the superconducting V_3Ga particles

    Humidification of Base Flow Gas during Adult High-Frequency Oscillatory Ventilation:An Experimental Study Using a Lung Model

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    In adult high-frequency oscillatory ventilation (HFOV) with an R100 artificial ventilator, exhaled gas from patientʼs lung may warm the temperature probe and thereby disturb the humidification of base flow (BF) gas. We measured the humidity of BF gas during HFOV with frequencies of 6, 8 and 10Hz, maximum stroke volumes (SV) of 285, 205, and 160ml at the respective frequencies, and, BFs of 20, 30, 40l/min using an original lung model. The R100 device was equipped with a heated humidifier, HummaxⅡ, consisting of a porous hollow fiber in circuit. A 50-cm length of circuit was added between temperature probe (located at 50cm proximal from Y-piece) and the hollow fiber. The lung model was made of a plastic container and a circuit equipped with another HummaxⅡ. The lung model temperature was controlled at 37℃. The HummaxⅡ of the R100 was inactivated in study-1 and was set at 35℃ or 37℃ in study-2. The humidity was measured at the distal end of the added circuit in study-1 and at the proximal end in study-2. In study-1, humidity was detected at 6Hz (SV 285ml) and BF 20l/min, indicating the direct reach of the exhaled gas from the lung model to the temperature probe. In study-2 the absolute humidity of the BF gas decreased by increasing SV and by increasing BF and it was low with setting of 35℃. In this study setting, increasing the SV induced significant reduction of humidification of the BF gas during HFOV with R100

    MCA morphology and BAD

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    Introduction : Branch atheromatous disease (BAD) is a type of cerebral infarction caused by stenosis or occlusion at the entrance of the penetrating branch due to the presence of plaque. Despite its clinical significance, it is not clear how these plaques are formed. Focal geometrical characteristics are expected to be as important as vascular risk factors in the development of atherosclerosis. This study aimed to analyze the association between middle cerebral artery (MCA) geometric features and the onset of BAD. Shear stress results from the blood flow exerting force on the inner wall of the vessels and places with low wall shear stress may be prone to atherosclerosis. At the curvature of blood vessels, the shear stress is weak on the inside of the curve and plaque is likely to form. When this is applied to the MCA M1 segment, downward type M1 is likely to form plaques on the superior side. Because the lenticulostriate artery usually branches off from the superior side of the MCA M1 segment, in downward type M1, a plaque is likely to be formed at the entrance of the penetrating branch, and for that reason, BAD is likely to onset. Methods : We retrospectively reviewed hospitalized stroke patients with BAD and investigated the morphology of their MCA using magnetic resonance imaging. The M1 segment was classified as straight or curved. Additionally, we compared the difference between the symptomatic and the asymptomatic side. Data regarding patients’ medical history were also collected. Results : A total of 56 patients with lenticulostriate artery infarctions and BAD were analyzed. On the symptomatic side, downward type M1 accounted for the largest proportion at 44%, whereas on the asymptomatic side, it was the lowest, at 16%. Conclusion : A downward type MCA may be associated with the onset of BAD and the morphological characteristics might affect the site of plaque formation

    Mean Lung Pressure during Adult High-Frequency Oscillatory Ventilation: An Experimental Study Using a Lung Model

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    In adult high-frequency oscillatory ventilation (HFOV), stroke volume (SV) and mean lung pressure (PLung) are important for lung protection. We measured the airway pressure at the Y-piece and the lung pressure during HFOV using a lung model and HFOV ventilators for adults (R100 and 3100B). The lung model was made of a 20-liter, airtight rigid plastic container (adiabatic compliance: 19.3ml/cmH2O) with or without a resistor (20cmH2O/l/sec). The ventilator settings were as follows: mean airway pressure (MAP), 30cmH2O;frequency, 5-15Hz (every 1Hz);airway pressure amplitude (AMP), maximum;and % of inspiratory time (IT), 50% for R100, 33% or 50% for 3100B. The measurements were also performed with an AMP of 2/3 or 1/3 maximum at 5, 10 and 15Hz. The PLung and the measured MAP were not consistently identical to the setting MAP in either ventilator, and decreasing IT decreased the PLung in 3100B. In conclusion, we must pay attention to the possible discrepancy between the PLung and the setting MAP during adult HFOV

    Angioscopic Observation After Coronary Angioplasty for Chronic Coronary Occlusion Comparison With Severe Stenotic Lesion

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    Objectives To clarify the underlying mechanism for the high restenosis rate after the coronary angioplasty for the chronic total occlusion by using the coronary angioscope

    Lansoprazole inhibits mitochondrial superoxide production and cellular lipid peroxidation induced by indomethacin in RGM1 cells

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    Lansoprazole is effective in healing non-steroidal anti-inflammatory drugs induced ulcers, and antioxidant properties have been thought to play a key role in healing ulcers. We hypothesize that lansoprazole exerts a cytoprotective effect by inhibiting reactive oxygen species leakage from mitochondria and lipid peroxidation. We pretreated gastric epithelial RGM1 cells with lansoprazole and then treated them with indomethacin in vitro. We found that the lansoprazole pretreatment significantly reduced cellular injury, maintained mitochondrial transmembrane potential, and decreased lipid peroxidation. Furthermore, the signal intensity of the electron spin resonance spectrum of the indomethacin-treated mitochondria which were pretreated with lansoprazole showed considerable reduction compared to those without the lansoprazole pretreatment. These results suggest that lansoprazole reduced superoxide production in the mitochondria of indomethacin treated cells, and subsequently inhibited lipid peroxide and cellular injury in gastric epithelial cells

    大型核融合試験施設におけるメガワットミリ波ジャイロトロン発振器周辺の電磁環境調査

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    将来のエネルギー源として開発が進められている磁場閉じ込め方式の核融合研究では,高温プラズマの生成や制御,プラズマ加熱及び計測のために大電力高周波発振機器が利用されている.本論文では,核融合科学研究所の大型ヘリカル装置で使用されているメガワットミリ波ジャイロトロン発振器(周波数: 77 GHz,最大出力: 1~1.5 MW/2秒)を対象とし,作業従事者の安全管理を目的に,ホーンアンテナを用いて機器周辺での電磁環境を定点調査した.その結果,77 GHz発振器からおよそ30 m離れた場所で観測された漏洩電界の周波数は,77 GHzが最も強く,そこから数GHz離れた両側の周波数領域にも微弱なスプリアススペクトルが確認された.また,同じ場所で,数十秒から数百秒の発振運転に伴う漏洩電界(最大実効値: 数V/m)が観測された.電界の漏洩箇所は,ジャイロトロン発振器を構成する接地電位の電子ビームコレクターと,その他の部位とを電気的に絶縁するために具備された窒化ケイ素製絶縁部と推定された.本研究により,大型核融合試験施設におけるメガワットジャイロトロン発振器周辺のミリ波帯での漏洩電界の実態を初めて明らかにした

    Diagnosis of visceral leishmaniasis by polymerase chain reaction of DNA extracted from Giemsa\u27s solution-stained slides.

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    Visceral leishmaniasis (VL) is caused by the protozoan parasite Leishmania donovani and is a potentially fatal disease in endemic areas of the world. Nepal is an endemic area in which VL causes major public health problems in the lowland areas of the southeast regions. The aim of the present study was to evaluate the sensitivity of polymerase chain reaction (PCR) amplification for the detection of Leishmania DNA from Giemsa\u27s solution-stained bone marrow slides. Bone marrow samples were aspirated from a total of 115 VL suspected patients and used to prepare smears on glass slides and for the initiation of in vitro culture. Bone marrow slides were used for microscopic observation, DNA extraction, and subsequent PCR amplification. PCR analysis showed that all the positive samples were of Leishmania parasites. The PCR assay also showed a higher sensitivity (69%) than microscopic examination (57%) and culture (21%). In addition, PCR was able to detect VL in 12% of samples which were negative by microscopy. PCR of DNA extracted from Giemsa\u27s solution-stained bone marrow slides is a suitable tool for confirming diagnosis in patients with VL and may also be useful in the diagnosis of difficult cases. Bone marrow smears are easily stored and can be easily sent to research centers where PCR is available. This makes PCR a good option for diagnosis in the field

    混合脂肪酸の簡易定量分析

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    脂肪酸のp-ブロムフェナシルエステル・2,4-ジニトロフェニルヒドラゾンおよびその酢酸第二水銀附加物のペーパークロマトグラムをつくり, スポットのベンゾール抽出液を比色して脂肪酸の簡易定量を行つた。本法を人為混合脂肪酸および天然油脂成分脂肪酸の分析に応用して良好な結果を得た。本研究に当り御懇篤なる御指導を賜つた西京大学農学部野田教授並に京都大学農学部井上教授に対し深甚の謝意を表する。A paper chromatographic method of p-bromophenacyl ester derivatives of fatty acids was successfully applied to the quantitative analyses of fatty acid mixtures. The usefulness of the technique was discussed from the results in application to some artficial and natural fatty acid mixtures

    Influence of genetic factors on the ephedrine alkaloid composition ratio of Ephedra plants

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    We investigated the ephedrine alkaloid [(-)-ephedrine and (+)-pseudoephedrine] composition ratio of a crude Chinese herbal drug described in the Japanese Pharmacopoeia \u27Ephedra herb (Chinese name: Mahuang)\u27. There were marked changes in the alkaloid composition ratio of wild plants in areas where both male and female clusters coexisted. However, in genetically homogeneous areas with the growth of male or female clusters alone, all of the coefficients of the regression lines were positive, but each gradient varied. This suggests that the alkaloid composition ratio has a clear tendency in each individual. Based on this, we cultivated individuals for vegetative propagation, and evaluated the alkaloid content ratio. Those propagated by separating the roots showed a specific tendency regardless of the cultivation area (Wakayama, Tanegashima). Those propagated by separating the herbaceous stem showed a specific tendency regardless of the soil or harvest time. In addition, we surveyed the (-)-ephedrine content ratio of 3- to 6-year-old strains. There was a high positive correlation coefficient between the previous and subsequent years. These findings suggest that the ephedrine alkaloid composition ratio of Ephedra herb depends on genetic factors, but not on environmental factors or the growth period
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