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Dysregulation of gastric H,K-ATPase by cigarette smoke extract

World Journal of Gastroenterology 2009年第32期15卷 4016-4022页

作者： Muna Hammadi mohamed adi Rony John Ghalia AK Khoder Sherif M Karam Department of Anatomy Faculty of Medicine & Health SciencesUAE UniversityAl-AinPO Box 17666United Arab Emirates

AIM:To test whether the expression and activity of H,K-ATPase in parietal cells would be affected by cigarette smoke extract.METHODS: Extracts of cigarette smoke were administered into mice by gastric gavage (5 mg/kg body weight/day) for 3 d or in drinking water for 7 or 14 d. For the latter, each day a mouse consumed 5 mL water containing extracts of two cigarettes, on average. Control littermate mice received only vehicle. To compare the amount of H,K-ATPase in control and smoke-treated mice, the stomach was processed for Western blotting and immunohistochemical analysis using monoclonal antibodies specific for α- or β-subunits of H,K-ATPase. The p-nitrophenylphospatase activity assay was used as a measurement for K-dependent H,K-ATPase activity.RESULTS: Probed transblots showed an increase in the amount of H,K-ATPase in smoke-treated mice which was confirmed by immunohistochemistry and was found to be due to increased amounts of protein per parietal cell rather than an increased parietal cell number. The increase in the amount of H,K-ATPase was associated with an enhancement of its enzymatic activity. K-dependent activity in control and smoke-treated mice was significantly different (respectively, 0.12 μmol/mg vs 0.27 μmol/mg per minute, P<0.05).CONCLUSION: Administration of cigarette smoke extract is associated with an increase in the amount and activity of H,K-ATPase and hence, smokers are susceptible to development of peptic ulcer.

关键词：香烟烟雾提取物活性酶灌胃 ATP酶免疫小鼠失调单克隆抗体

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Effect of Cast Thickness and Austenitizing Temperature on Microstructure and Mechanical Properties of adi and Iadi Castings

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Open Journal of Metal 2021年第3期11卷 21-35页

作者： A. M. Negm S. S. mohamed Mervat M. Ibrahim Moussa Ibrahim Khaled M. Ibrahim Modern Academy for Engineering and Technology Cairo Egypt Faculty of Engineering at Shoubra Benha University Cairo Egypt Central Metallurgical Research and Development Institute Cairo Egypt

This investigation studies the impact strength, tensile strength, hardness, and wear behavior of thin wall austempered and intercritically austempered ductile iron samples with a chemical composition of 3.37% C, 2.7% Si, 0.30% Mn, 0.01% S, and 0.01% P. The austempered samples were austenitized at 900?C for 1 h and rapidly quenched in a salt bath furnace at 375?C for 1 h. The intercritically austempered samples were sub-austenitized at 810?C for 1 h and rapidly quenched in a salt bath furnace at 375?C for 1 h. The properties of the austempered and intercritically austempered thin wall plates of 5, 10, and 15 mm thickness were evaluated and compared to the as-cast samples. Austempering process affects greatly the tensile properties of all cast thicknesses where ultimate strength reached 1004 MPa for 5-mm thickness. Optimum impact toughness of 40 J was obtained for the austempered samples of 10- and 15-mm thicknesses. The intercritically austempered samples showed properties between the austempered and as-cast samples. Maximum wear resistance was also reported for the austempered samples due to containing retained austenite in the structure which in turn transformed into martensite that increases well the wear resistance. Maximum ultimate strength (1056) MPa and hardness (396 HV) were obtained for 5 mm adi sample. Maximum impact toughness (43 J) was achieved for 15 mm Iadi sample due to existing of pro-eutectoid ferrite in matrix. For all As-cast, adi and Iadi irons, wear resistance decreased with increasing sample thickness. Minimum wear rate (2.22 × 10?6 g/s) was reported for 5-mm adi sample and maximum one (15.8 × 10?6 g/s) was registered for 15-mm as-cast DI sample, at a sliding speed of 2 m/s.

关键词： DI adi Iadi Retained Austenite Wear Resistance

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