Effect of steviol and its structural analogues on glucose production and oxygen uptake in rat renal tubules

The effect of several natural products of Stevia rebaudiana on glucose production and oxygen uptake in rat renal cortical tubules was investigated. Steviol, isosteviol and glucosilsteviol decreased glucose production and inhibited oxygen uptake. The sweet principle stevioside, and steviolbioside, however, were without effect on gluconeogenesis and oxygen uptake.     

The effect of hypoxia on hepatic cytochromes and heme turnover in rats in vivo

We evaluated the effect of hypoxia (7% v/v) on hepatic heme turnover in vivo and microsomal heme protein content in male Sprague-Dawley rats. Hepatic heme protein turnover, measured as 14CO-production during continuous infusion of 5-14C-aminolevulinic acid, a precursor of nonerythrogenic heme, was decreased 60% during hypoxia and returned to control levels promptly after reoxygenation. Hepatic cytochrome P-450 content was decreased in hypoxic and 24-h reoxygenated animals. We conclude that normobaric hypoxia decreases hepatic cytochrome P-450 which could contribute to decreased drug metabolism in hypoxia. This decrease is probably due to heme oxygenase-independent breakdown of hepatic heme.     

Postoperative hypoxia after extracorporeal circulation: A possible graft against host reaction (preliminary communication)

Zusammenfassung Bei Patienten, bei welchen ein extrakorporaler Blutkreislauf durchgeführt wurde, fanden sich in den Lungen grosse Mengen von Plasmazellen. Bei Benützung von frischem homologem Blut für die Ingangsetzung des extrakorporalen Kreislaufes scheinen die Plasmazellen des Spenderblutes in den Lungen schädigend zu wirken. Sie können möglicherweise für Kapillarschädigungen und Störungen des normalen Gasaustausches verantwortlich gemacht werden.     

Action of tobacco on lipolysis and its modification by insulin

Resumen Los fumadores habituales tienen niveles de FFA significantivamente más altos que los no fumadores. El acto de fumar incrementa la lipolisis. Fumar sin inhalar el humo produce incremento de lipolisis. La insulina inhibe la accion lipolítica del humo de tabaco.     

Genetic analysis of modifier variability inDrosophila subobscura

Summary The previously detected modifier variability acting on the expression of the Bare (Ba) locus inDrosophila subobscura is demonstrated to be due to polygenes situated along the chromosome O. From crosses between isogenic lines of high and low modifier effect we ascertained the presence of approximately 5 modifier loci.We are grateful to Dr M. Green for valuable comments on the experimental design used in this paper.     

热输入对深海X70粗晶区组织和韧性的影响

为解决深海X70管线钢在实际焊接中粗晶区(CGHAZ)的脆化问题,在不同热循环工艺下对X70管线钢进行了热模拟研究。采用Gleeble-3800热模拟机模拟X70管线钢CGHAZ,研究CGHAZ在10～60 kJ/cm不同热输入(HI)条件下组织和韧性的变化规律,并通过光学显微镜(OM)、扫描电镜(SEM)和夏比冲击试验等手段表征CGHAZ的组织和韧性。结果表明,不同热输入下试验钢的组织主要由粒状贝氏体(GB)、贝氏体铁素体(BF)和马-奥组元(M-A组元)组成;当HI不断增大时,BF比例减少,GB比例增加,M-A组元粗化,冲击吸收能先升高再降低;当HI为20 kJ/cm时,BF和GB可获得优异组合,断口为韧性断裂,冲击吸收能达到173.8 J;当HI大于20 kJ/cm时,断口解离断裂,冲击吸收能下降明显,最低为18.8 J。因此,较低的热输入可提高CGHAZ的韧性,使X70管线钢具有高强度、高韧性和良好的焊接性。研究结果可为优化焊接工艺提供理论依据。     

临近空间等离子体鞘套对太赫兹波传播特性分析

针对高超声速飞行器在临近空间巡航时出现的通信"黑障"问题,根据RAM C提供的飞行试验数据,建立一维等离子体鞘套模型,通过数值计算分析了等离子体与太赫兹波的相互作用机理,并从等离子体厚度、等离子体电子密度、等离子体碰撞频率和太赫兹波入射角等条件得到了太赫兹波在等离子体鞘套中的传输特性曲线。仿真结果表明:把太赫兹波段作为临近空间平台通信,有利于解决"黑障"问题,其中在大气窗口0.22THz处的衰减均在30dB以下。此论证结果可为临近空间平台设计的高超声速飞行器选用通信频段时提供参考。     

Emergence of a new satellite RNA from cucumber mosaic virus isolate P1

The cucumber mosaic virus (CMV) isolate P1 caused very mild symptoms on many plant species.After serial passages by mechanical inoculation over five years, CMV P1 caused severe symptoms on several tobacco cultivars and tomato. A specific band of approximately 0.3 kb in length was amplified by RT-PCR with primers synthesized based on reported CMV satellite RNA (satRNA) sequences. Sequence analysis showed there were two satRNAs (Sat-Pl-1 and Sat-P1-2). Sat-Pl-1 contained 335 nucleotides, and Sat-P1-2 contained 394 nucleotides. These two satRNAs shared 64% overall nucleotide sequence homology, and differences between the two satRNAs included mutations as well as deletions. Sat-Pl-1 was identical to a satRNA (Z96099) reported in 1995 in CMV P1. Based on differences in the sequence and secondary structure between these two satRNAs, we conclude that Sat-P1-2 represents the emergence of a new satellite ( necrotic satellite) from attenuated satRNA populations. The possible effect of the emergence of this new satRNA is discussed.