Geometry of screw compressor rotors and their tools     

Nikola STOSIC  Ian K. SMITH  Ahmed KOVACEVIC  Elvedin MUJIC 《浙江大学学报(A卷英文版)》2011,12(4):310-326

This paper presents a method of general geometrical definitions of screw machine rotors and their manufacturing tools. It describes the details of lobe shape specification, and focuses on a new lobe profile, which yields a larger cross-sectional area and shorter sealing lines resulting in higher delivery rates for the same tip speed. A well proven mathematical model was used to determine the optimum profile, compressor housing size, and compressor ports to achieve the superior compressors.  相似文献   

Knowledge sharing through pair programming in learning environments: An empirical study     

R. K. Kavitha  M. S. Irfan Ahmed 《Education and Information Technologies》2015,20(2):319-333

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“P53 Codon 72 Single Base Substitution in Viral Hepatitis C and Hepatocarcinoma Incidences”     

Emad F. Eskander  Ahmed A. Abd-Rabou  Shaymaa M. M. Yahya  Ashraf El Sherbini  Mervat S. Mohamed  Olfat G. Shaker 《Indian journal of clinical biochemistry : IJCB》2014,29(1):3-7

Viral infection with hepatitis C virus (HCV) has a high propensity in becoming chronic and it is the major cause of hepatocellular carcinoma (HCC) worldwide. This review was basically established to illustrate the putative role of the P53 gene Arg72Pro polymorphism on various cancer models and viral infections, focusing on HCV and HCC incidences. Authors studied the 72 G/C single base substitution of P53 gene at codon 72 using various polymorphic techniques. Intriguingly, authors investigated that the P53 codon 72 plays a crucial role as risk factor in several cancer models. Others found that there is no association between codon 72 genotypes and HCV disease severity or liver cancer. Moreover, the lack of a significant relationship between this polymorphism and risk of HCC shows that it does not predispose towards hepatocarcinogenesis and the frequent loss of the proline allele in HCV-associated carcinogenesis of the liver plays some critical role in hepatocarcinogenesis. Amazingly, there is a significant correlation between male homozygotes for P53 72Pro with HCV type 1b infection. However, there was no significant difference between the P53 polymorphism and HCV genotypes 2a and 2b. It was concluded that the P53 gene polymorphism at codon 72 has been investigated as potential risk factor in several cancer models and HCV infections.  相似文献   

Overexpression of Aldose Reductase Render Mouse Hepatocytes More Sensitive to Acetaminophen Induced Oxidative Stress and Cell Death     

Munzir M. E. Ahmed  J. A. S. Al-Obosi  H. M. Osman  M. E. Shayoub 《Indian journal of clinical biochemistry : IJCB》2016,31(2):162-170

Acetaminophen (APAP) a commonly used drug for decrease the fever and pain but is capable to induced hepatotoxicity at over dose. This study was carried out to investigate the effect of APAP on the expression of anti-apoptotic and antioxidative defense genes, and whether aldose reductase over-expressing plasmid capable to protect against APAP-induced oxidative stress and cell death. APAP treatment induced oxidative stress and hepatotoxicity, and significantly increased aldose reductase mRNA and protein expression in mouse hepatocyte (AML-12). Unexpectedly, AML-12 cells over-expressing aldose reductase augmented APAP-induced reduction in cell viability, reactive oxygen species (ROS) production, glutathione (GSH) depletion and glutathione S-transferase A2 expression. Moreover, over-expression of aldose reductase potentiated APAP induced reduction on proliferating cell nuclear antigen, B cell lymphoma-extra large (bcl-x_L), catalase, glutathione peroxidase-1 (GPx-1) and abolished APAP-induced B-cell lymphoma 2 (bcl-2) inductions. Further, over-expression of aldose reductase significantly abolished AMP activated protein kinase (AMPK) activity in APAP-treated cells and induced p53 expression. This results demonstrate that APAP induced toxicity in AML-12, increased aldose reductase expression, and over-expression of aldose reductase render this cell more susceptible to APAP induced oxidative stress and cell death, this probably due to inhibition AMPK or bcl-2 activity, or may due to competition between aldose reductase and glutathione reductase for NADPH.  相似文献   

花状氧化铁的制备及其在废水处理中的应用     

Kun XIE  ;Xiang-xue WANG  ;Zheng-jie LIU  ;Ahmed ALSAEDI  ;Tasawar HAYAT  ;Xiang-ke WANG 《浙江大学学报(A卷英文版)》2014,15(8):671-680

研究目的：研究花状氧化铁的制备并探讨其对砷的吸附性能和亚甲基蓝的催化性能。 创新要点：1.合成了花状氧化铁;2.发现Langmuir模型能更好地模拟砷的吸附过程;3.发现花状氧化铁对亚甲基蓝有很好的催化降解性能。 研究方法：1.使用扫描电镜、投射电镜、X射线衍射和BET比表面及孔径分析仪对合成的花状氧化铁进行表征;2.采用静态实验法研究砷的吸附性能及亚甲基蓝的催化行为。 重要结论：1.采用一种低成本的溶剂热法合成了花状氧化铁;2.合成的花状氧化铁有着较大的比表面积并对砷有着很好的吸附性能,并且吸附率随着pH的增加而降低。同时发现Langmuir模型能更好地模拟砷的吸附过程;3.亚甲基蓝的初始浓度和花状氧化铁的用量对催化性能影响较为明显,花状氧化铁有较好的重复利用性;4.合成的花状氧化铁可以应用于大批废水的处理。  相似文献   

Game-based learning platform to enhance cybersecurity education     

Khan  Manzoor Ahmed  Merabet  Adel  Alkaabi  Shamma  Sayed  Hesham El 《Education and Information Technologies》2022,27(4):5153-5177

Education and Information Technologies - Computer security competitions have been playing a significant role in encouraging students to get into cybersecurity, as well as enhancing the...  相似文献   

World Bank assistance in education     

Manzoor Ahmed 《Prospects》1981,11(1):25-35

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Book reviews     

Ahmed Moatassime  Alejandro Dorna 《Prospects》1984,14(1):164-168

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Science in the Indian Universities     

Rais Ahmed  Madhulika Rakesh 《Minerva》1992,30(1):51-61

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Negotiating Academic Learning and Research: The Spiritual Praxis of Graduate Students of Color     

Riyad Ahmed Shahjahan  Lara Barker 《Equity & Excellence in Education》2013,46(4):456-472

Drawing on data collected in a qualitative study of racially minoritized faculty members, this article examines the challenges these faculty members faced in bringing different aspects of their spirituality into their scholarly work as graduate students. This article explores the questions: How do racially minoritized graduate students negotiate their spiritual identities and integrate their spiritual epistemologies and cultural knowledge into academic practices, and what challenges do they face in doing both? This article presents three salient themes: sacred subjectivity in student-focused research, spiritual praxis in the classroom, and new visions for inclusive spiritual expression in the academy. By focusing our analysis on study participants' strategies for resisting pressures to closet their beliefs, this article affirms the importance of legitimizing the spiritual epistemological perspectives of racially minoritized graduate students in creating a more equitable and diverse higher education culture.  相似文献