Solvent influence in the formation of normal and abnormal carbene complexes in reactions of imidazolium salts with [Ir(H)2(PPh3)2(OCMe2)2]BF4

Abnormal and normal carbene complexes are formed in reactions of 2-pyridylmethylimidazolium salts with [Ir(H)₂(PPh₃)₂(OCMe₂)₂]BF₄ at room temperature in tetrahydrofuran (THF) or dichloromethane (CH₂Cl₂). Reactions in THF lead to the formation of abnormal carbene (C-5 bound), while reactions in CH₂Cl₂ lead to formation of normal carbene (C-2 bound).     

海军指战员心理健康状况研究现状

我国军人的心理健康状况从80年代后期开始有了较为系统的研究。海军指战员是社会的特殊群体,健康的心理素质可以使海军指战员保持战斗力,更好的适应国防现代化的需要。海军指战员在一段较长的时间内,整日面对单一枯燥的环境,承受巨大工作压力,加之其他一些影响因素,难免产生诸多心理问题。因此,探讨职业特殊环境对海军指战员心理健康造成的影响,对海军指战员人格结构及心理健康状况进行评价,用以指导海军官兵在特殊环境中提高心理素质,避免不良影响,最终提高部队战斗力具有十分重要的意义。通过查阅文献了解海军特殊职业环境对士兵心理健康影响的研究现状,总结当前应用的各种评价工具、异常心理状况、影响因素及其危害,分析海军心理健康研究方面存在的不足与亟待解决的问题,为今后的研究提供参考。     

一种异常的捻转血矛线虫

从自然感染羊上采集的捻转血矛线虫,发现部分虫体头部有明显的头翼膜样结构或类似的痕迹,此种结构过去未有记载。分别取正常和异常雌虫虫卵进行培养,观察幼虫发育过程并比较幼虫形态变化。发现正常和异常虫体第三期幼虫(L3)的虫体长度和食道长度差异极显著,虫体宽度和尾鞘长度差异不显著。     

抑制大鼠褪黑素的合成对神经细丝过度磷酸化的影响

目的探讨抑制褪黑素的生物合成对大鼠海马神经细丝过度磷酸化的影响及其可能机制.方法侧脑室注射氟哌啶醇并腹腔注射加强,HPLC检测血清中褪黑素水平;利用免疫组化检测大鼠海马区域神经细丝磷酸化情况;微量测定法测定超氧化物歧化酶(SOD)活性和脂质过氧化产物丙二醛的含量.结果①模型组大鼠血清中褪黑素的含量明显下降.②海马区域神经细丝发生聚集和异常过度磷酸化,补充不同剂量的褪黑素的治疗组较模型组的磷酸化程度有所改善.③模型组SOD活性降低,丙二醛(MDA)含量明显升高.结论褪黑素水平的降低引起AD-样神经细丝异常过度磷酸化,外源性补充褪黑素可以一定程度上减轻神经细丝的异常过度磷酸化.     

抑制褪黑素生物合成对大鼠Tau蛋白磷酸化的影响

目的 研究抑制褪黑素的生物合成对大鼠海马Tau蛋白磷酸化的影响。方法 侧脑室注射氟哌啶醇并腹腔注射加强,利用免疫组化检测大鼠海马区域Tau蛋白磷酸化情况;HPLC检测血清中褪黑素水平。结果 模型组大鼠海马Tau蛋白在Ser199/Ser202和Ser396/Ser404位点均发生异常过度磷酸化,褪黑素治疗组较模型组的磷酸化程度轻。结论 褪黑素水平的降低可能与AD样Tau蛋白异常过度磷酸化相关,外源性补充褪黑素可以减轻Tau蛋白的异常过度磷酸化。     

富亮氨酸alpha2 糖蛋白1（LRG1）在肿瘤中的研究进展

富亮氨酸琢2 糖蛋白1(Leucine-rich-alpha-2-glycoprotein1,LRG1）是富亮氨酸重复序列(leucine-rich repeat, LRR)家族蛋白成 员之一。LRG1 在人类多种肿瘤中表达异常,可以作为部分肿瘤早期诊断的潜在生物标记,而且这种异常表达可能提示患者预后 不良。LRG1 在肿瘤的发生、侵袭转移、上皮间质转化和血管生成中发挥重要作用。这些环节中,协同参与调控的辅助因子众多且 有差异,因而经历的信号途径有所不同。本文综合目前的研究进展,旨在阐述LRG1 与肿瘤的关系以及其调控肿瘤发生发展的分 子机制。LRG1 有望成为一种新的肿瘤分子标志物,将为恶性肿瘤的分子诊断及靶向治疗提供新的方向和手段。     

Metabolism of Cytokinins by Tissue Culture Lines of Oil Palm (Elaeis guineensis Jacq.) Producing Normal and Abnormal Flowering Palms

The metabolism of cytokinins in tissue cultures of two oil palm clones previously known to regenerate palms ultimately manifesting normal and abnormal flowering was studied using radiolabeled benzyladenine and isopentenyladenosine, with particular regard to the kinetics of formation of the cytokinin 9-glucoside. Labeled products were separated by high performance liquid chromatography and identified by comparison of retention times with authentic cytokinin standards run immediately before or after the experimental sample. Using benzyladenine, which is insensitive to cytokinin oxidase, ribotide appeared rapidly and then declined. 6-Benzylaminopurine (BA) 9-glucoside quickly became the major soluble product with some formation of riboside. No other ethanol-soluble products were found. Over an incubation period of 24 h up to 30% of label appeared in the ethanol-insoluble fraction. The uptake of label was consistently faster in the normal than the abnormal clone. Dose-rate and time course experiments produced an in vivo asymptotic dose-response curve for the accumulation of BA 9-glucoside analogous to a Michaelis-Menten first-order reaction with a ~~``V <sub>max</sub>' of 3.5 nmol·g<sup>−1</sup>·h<sup>−1</sup> (on a fresh weight basis) and a ``K _m ' of 0.12 mm. There were no differences between clones in the rate of synthesis. Using isopentenyladenosine, which is susceptible to cytokinin oxidase and cannot be glucosylated without prior deribosylation, a complex pattern of metabolism was seen, with much slower production of 9-glucoside. A number of transient unidentified compounds were seen, together with adenosine and adenine. Comparison of normal and abnormal flowering clones showed striking differences in the kinetics of production of a compound thought to be [9R]Z and in a transient compound eluting at 22 min which accounted for 42% of the radioactivity after a 7-h incubation in the abnormal line. By 17 h there was no difference between normal and abnormal lines in the radioactivity in this compound. Cytokinin uptake was slower in the abnormal than in the normal flowering clone. Received December 17, 1997; accepted August 24, 1998     

^60Co—r射线辐射番茄种子对根尖细胞遗传学效应的影响

用６０Ｃｏ－ｒ射线辐射番茄干种子,水培法生根后,观察根尖细胞有丝分裂中出现的桥、断片（含落后）、粘连、微核等染色体畸变类型,辐射剂量在５—１０ｋｒａｄ范围内畸变率较低;在１０—２０ｋｒａｄ范围内畸变率最高,畸变类型最丰富,在此范围内随剂量增加,断片数量增多,桥的类型除单桥外还出现多桥且数量增多,在２０ｋｒａｄ以上范围的高辐射剂量对染色体破坏力力较大,不利于番茄育种和生长。经对照实验和统计分析可知,辐射剂量的增加对有丝分裂有抑制作用。     

农药残留预测模型参数估计过程的灵敏度分析

本文根据矩阵理论运用摄动分析的方法,揭示了最小二乘法参数估计过程“病态”正规方程组问题,及运用“病态”正规方程组进行参数估计给预测模型带来的影响．最后根据矩阵的条件数理论,提出了对农药残留预测模型参数估计过程进行灵敏度分析的数学方法．     

Hemoglobin vancouver [α2β2 73(E17) Asp→ Tyr]: Its structure and function

Summary Hemoglobin Vancouver is a new abnormal hemoglobin with an amino acid substitution of the normal aspartyl residue 73 of the chain by a tyrosyl residue. It was discovered in a man of Chinese descent in association with thalassemia. It was subsequently detected in a sister in association with normal Hb A. The oxygen affinity of the abnormal hemoglobin is decreased but its subunit interaction is normal. The Bohr effect may be slightly increased.This is the fourth abnormal hemoglobin to be found with a substitution at73. The others are Hb C-Harlem ( _{2 2} 6GluVal and 73 AspAsn), Hb Korle-Bu ( _{2 2} 73 AspAsn), and Hb Mobile ( _{2 2} 73 AspVal). Although Hb Mobile was found in the present studies to have a decreased affinity for oxygen, Hbs C-Harlem and Korle-Bu have been reported to be normal. These observations of functional differences for variants of73 added to earlier observations of the role of the normal73 residue to the aggregation of sickle deoxyhemoglobin indicate that this position of the molecule may be important in intra as well as intermolecular interactions.