A possible role for cell proliferation in potassium bromate (KBrO3) carcinogenesis

Accumulation of alpha 2u-globulin and induction of cell proliferation were examined in kidneys of rats exposed to KBrO3, KBr or NaBrO3 in their drinking water. Hyaline droplets observed after KBrO3 or NaBrO3 administration to male rats were specifically immunostained for alpha 2u-globulin. Increases in cell proliferation were found in the proximal tubules of male rats given KBrO3 or NaBrO3 but not KBr for 2, 4, and 8 weeks. No such change was evident in KBrO3-treated female rats or the distal tubules of any treated animal. The concordance between hyaline droplet accumulation and increased cell turnover suggests that KBrO3- and NaBrO3-induced cell replication in kidneys of male rats may result from alpha 2u-globulin nephropathy. Considering the fact that KBrO3 has genotoxic potential involving oxidative stress, we hypothesize that the induced cell proliferation might predominantly play an additive role in its carcinogenesis. Furthermore, the present data, showing similar effects of NaBrO3 on the rat kidney, are of direct significance to its risk assessment.     

添加RE的银基汞齐合金的研究和应用

用雾化技术制备Ａｇ－Ｃｕ－Ｓｎ汞齐合金并添加ＲＥ及Ｉｎ，Ｌｉ，研究其性能和结构，临床试验表明，此合金具有优良综合性能，Ｈｇ用量少，成本也低。     

银杏美肌物语

我们经常可以在一些美容护肤品的成分说明中，看到“银杏”的字样，那么，它到底有怎样的神奇功效呢？[编者按]     

Sensing-based opportunistic channel access

Enabled by regulatory initiatives and advanced radio technologies, more flexible opportunistic spectrum access has great potential to alleviate the spectrum scarcity. In this paper, we study the channel selection issue of secondary users in spectrum-agile communication systems. We focus on the sensing-based approach because it is simple and has low infrastructure requirements. We propose a two-step approach for channel selection. The first step is to determine whether or not a channel is idle and thus accessible to secondary users. We propose three algorithms to perform the accessibility check based on measurements of primary signals. Then we address the question whether an accessible channel is a good opportunity for a secondary user. Xin Liu received her Ph.D. degree in electrical engineering from Purdue University in 2002. She is currently an assistant professor in the Computer Science Department at the University of California, Davis. Before joining UC Davis, she was a postdoctoral research associate in the Coordinated Science Laboratory at UIUC. Her research is on wireless communication networks, with a focus on resource allocation and dynamic spectrum management. She received the best paper of year award of the Computer Networks Journal in 2003 for her work on opportunistic scheduling. She received NSF CAREER award in 2005 for her research on “Smart-Radio-Technology-Enabled Opportunistic Spectrum Utilization.” Sai Shankar N received his PhD degree from the department of Electrical Communication Engineering from Indian Institute of Science, Bangalore, India for his work in the area of performance modeling of ATM networks. In 1998, He was awarded the German Fellowship, DAAD, in the department of mathematics, University of Kaiserslautern, Gernany to work on queueing approaches in manufacturing. In 1999, he joined Philips Research, Eindhoven, the Netherlands, where he served as Research Scientist in the department of New Media Systems and Applications working on various problems involving Hybrid, Fiber, Co-axial Cable (IEEE 802.14) Networks and IP protocols and provided efficient algorithms to improve protocol efficiency. In the year 2001 he joined Philips Research USA, Briarcliff Manor, NY and worked in the area of Wireless LANs/Ultra Wide Band (UWB), Cognitive Radios and Cooperative Communications. He was a key member in shaping the QoS related issues in IEEE 802.11e standardization and was one of the prime authors and inventors of the WiMEDIA UWB MAC protocol for which he was nominated as one of the five finalists in the Innovator of the year category by EE Times in year 2004. Besides these he has authored nearly 10 papers in the area of cognitive radios and holds fundamental patents on the design of MAC for cooperative communications. He has chaired numerical conferences and technical sessions and has delivered more than ten tutorials in leading international conferences of which two will appear in IEEE COMSOC webpage. He is also the Senior Member of the IEEE and has authored more than 50 conference and journal papers and holds more than 35 patents. Currently Sai Shankar is with Standards Engineering department of Qualcomm Inc. working on issues related to UWB and cognitive radios.     

Growth potential of Rana tigerina skin lipids in cell cultures

The structure of the hexameric L-alanine dehydrogenase from Phormidium lapideum reveals that the subunit is constructed from two domains, each having the common dinucleotide binding fold. Despite there being no sequence similarity, the fold of alanine dehydrogenase is closely related to that of the family of D-2-hydroxyacid dehydrogenases, with a similar location of the active site, suggesting that these enzymes are related by divergent evolution. L-alanine dehydrogenase and the 2-hydroxyacid dehydrogenases also use equivalent functional groups to promote substrate recognition and catalysis. However, they are arranged differently on the enzyme surface, which has the effect of directing opposite faces of the keto acid to the dinucleotide in each case, forcing a change in absolute configuration of the product.     

驼乳预防小鼠急性酒精性肝损伤的代谢组分析

目的：检测小鼠血清和肝脏生化指标,分析驼乳对小鼠急性酒精性肝损伤的预防作用,并结合代谢组学探究其机理。方法：将24只ICR雄性小鼠随机分为空白组(NC)、模型组(ET)和驼乳组(ET+CM),采用短时间灌胃大剂量(7.3 g/kg)酒精的方法复制急性肝损伤小鼠模型。通过测定血清指标(ALT,AST,SOD和GSH)和肝脏指标(TG和TC)来反映驼乳对肝脏的保护作用,并基于代谢组学的研究手段,探讨驼乳保肝、护肝的作用机理。结果：驼乳显著抑制了因酒精作用而升高的小鼠血清中ALT和AST以及肝脏中TG和TC水平;同时,驼乳可通过清除活性氧自由基,增加血清中SOD和GSH的含量。通过代谢组分析,在ET和NC组以及ET和ET+CM组中的差异代谢物,主要涉及脂质代谢、有机酸代谢和有机氧化合物;在NC、ET和ET+CM 3组中共筛选、鉴定出28个差异显著代谢物,其中灌胃酒精会降低肝脏中乙酰胆碱、甘氨酸、亚油酸、磷脂酰胆碱等含量,而灌胃驼乳会显著增加以上代谢物的含量。差异代谢物主要富集在胆碱代谢、甘油磷脂代谢和ABC转运蛋白通路中。结论：驼乳干预并缓解了小鼠急性酒精暴露诱导的脂质代谢紊乱,提高了抗氧化...     

基于线阵CCD的高反射物体图像采集设计与实现

介绍了一种应用于高反射物体金属标牌的图像采集装置,详细介绍了线阵CCD驱动电路的设计以及CCD信号的处理,并给出了时序仿真图形和程序流程图,最后通过对比实验,证实了该图像采集装置优于普通采集装置。     

添加剂LiBOB在LiCoO2体系中的性能研究

采用恒流充放电法研究了LiBOB对LiCoO2作正极体系高温循环性能的影响。使用DSC法分析了LiBOB对负极SEI膜热稳定性的影响。初步探讨了LiBOB对PC基电解质与MAG相容性的影响机理。交流阻抗法测试结果表明,LiBOB的添加使MAG电极表面形成一层稳定的固体电解液相界面膜(SEI),抑制了PC共嵌,并使循环性能得到改善。DSC结果分析表明,LiBOB使负极SEI膜的热稳定性得到了改善。     

建设领域责任保险体系框架建构设想

以建设项目全生命期为主线,论述建设项目相关参与主体的工作范围和内容,并按照相应的法律规定分析各参与主体在从事项目建设和管理过程中可能承担的民事法律责任,依此设计建设领域责任保险体系框架。     

Ammoxidation activity of in situ synthesized ammonium salt of molybdophosphoric acid on VOPO4 catalysts

Two isomorphous VOPO₄ samples were synthesized by means of well-known aqueous and organic preparation methods. These materials are further used for the in situ generation of ammonium salt of 12-molybdophosphoric acid (AMPA) from their solid phase phosphate components. Formation of AMPA was confirmed by XRD, FTIR, Raman and XPS analyses. The activity of the catalysts was tested in a fixed bed tubular glass reactor at atmospheric pressure for the selective ammoxidation of 2-methylpyrazine (MP) to 2-cyanopyrazine (CP). The reaction was carried out in the temperature range of 360–420 °C. Between the two mono-phosphates tested, the α-VOPO₄ is observed to show somewhat better activity compared to β-VOPO₄. Interestingly, in situ synthesized AMPA catalysts displayed significantly better performance compared to their corresponding parent VOPO₄ solids. Among all catalysts tested, AMPA-α-VOPO₄ exhibited the best performance (conversion (MP) = ca. 90%, selectivity (CP) = 65% at T = 420 °C). The differences in catalytic performance of the tested catalysts are ascribed to the structural differences of the used VOPO₄ solids.