镉胁迫对罗汉果幼苗生理生化特性的影响

[目的]研究不同浓度Cd胁迫对罗汉果幼苗生理生化特性的影响.[方法]通过盆栽试验,测定不同浓度Cd处理的罗汉果幼苗细胞膜透性,MDA、脯氨酸和可溶性糖含量,以及SOD、POD、CAT活性等各项生理生化指标.[结果]随着Cd浓度升高,细胞膜透性逐渐增大;在相对低浓度Cd(10 mg/kg)处理下 MDA、脯氨酸和可溶性糖含量均少于对照,而后随着Cd浓度的升高而明显上升;在较低Cd浓度胁迫条件下,SOD、POD、CAT活性变化不明显,但随着Cd浓度的升高,SOD、POD、CAT活性逐渐升高,然后又降低.[结论]高浓度Cd胁迫加重了叶片氧化程度并对罗汉果生长具有一定的抑制作用;而SOD、POD、CAT 活性的提高与维持是罗汉果耐Cd 胁迫的物质基础之一.     

铈缓解镉对玉米种子的毒害效应研究

采用水培实验的方法研究了不同浓度铈、镉单一及铈镉复合处理对玉米种子发芽率、α-淀粉酶活性、三种抗氧化酶(SOD、POD、CAT)活性、细胞膜脂过氧化产物丙二醛含量以及细胞膜透性的影响。结果表明,添加10 mg·L-1的Ce能缓解Cd对玉米种子的毒害,提高种子发芽率,增强α-淀粉酶活性、抗氧化酶(SOD、POD、CAT)活性,降低MDA含量和细胞质膜透性。当镉剂量为100 mg·L-1时,这种缓解作用不明显,甚至有加重毒害的趋势。     

麻疯树幼苗耐旱的保护性应答

采用聚乙二醇(PEG6000)胁迫,研究了干旱胁迫条件下麻疯树幼苗叶组织中抗氧化系统的变化.结果表明:在0～60 h胁迫中,麻疯树幼苗叶片相对含水量(Rwc)明显下降;处理36 h内,丙二醛(MDA)含量略有增加,但增幅不大,叶绿素含量增加;处理36 h后,MDA含量大幅增加,叶绿素含量逐渐下降;抗坏血酸(ASA)含量伴随胁迫处理开始增加,48 h后才逐渐下降;处理12 h检测到还原型谷胱甘肽(GSH)含量与GR活性开始上升,48 h后才开始下降,二者变化一致.抗氧化酶系统变化并不一致,SOD、CAT和APX活性在胁迫后都呈现先逐步增加而后缓慢下降的趋势,但各自酶活峰值出现在不同时期;POD活性则持续随处理时间的延长而增加,后期增幅逐渐减小;SOD,POD和APX活性在胁迫期间一直高于对照.     

外源亚精胺对盐胁迫下小麦幼苗生长的影响

[目的]为了解亚精胺是否能缓解盐胁迫对小麦幼苗生长的影响.[方法]采用滤纸培养法,研究了外源亚精胺(Spd) 对NaCl 胁迫下小麦幼苗生长和部分生理指标的影响.[结果]与对照相比,盐胁迫抑制了小麦幼苗的生长,增加了小麦中SOD、POD活性和MDA含量,降低了可溶性蛋白质含量.亚精胺处理明显促进了小麦幼苗的生长,提高了幼苗中SOD和POD活性,降低了MDA含量,提高了可溶性蛋白质含量.[结论]亚精胺能缓解盐胁迫对小麦幼苗的毒害作用,提高小麦幼苗的抗盐能力,但随处理时间的延长,亚精胺的缓解作用有所下降.     

SO2胁迫对茶条槭叶片6种保护酶活性的影响

[目的]研究不同SO<,2>胁迫处理对茶条槭叶片6种保护酶活性的影响.[方法]利用SO<,2>静态熏气系统时3年生茶条槭苗木进行胁迫处理,研究不同SO<,2> 浓度(0～6.0 mg/m<'3>)和熏气时间(0～6 h)下茶条槭叶片6种保护酶活性的变化趋势.[结果]随着SO<,2>浓度的增加,PPO和APX活性一直降低,SOD、CAT、POD和GR 活性表现为先迅速上升后下降的趋势,其中GR活性下降较平缓;在不同时间SO<,2>处理中,CAT和GR活性随着胁迫时间的延长先迅速上升而后下降,而SOD、POD、PPO和APX活性均随着胁迫时间的延长而降低,其中SOD和GR活性变化幅度较平缓.[结论]PPO、POD和APX活性下降可能是茶条槭幼苗SO<,2>伤害的原因之一,而SOD、CAT和GR活性变化平缓是茶条槭幼苗响应SO<,2>胁迫的适应性机制.     

PEG渗透胁迫下玉米幼苗叶片保护酶活性昼夜变化

[目的]了解逆境条件对植物体内保护酶活性昼夜变化的影响.[方法]用不同浓度聚乙二醇(PEC-6000)溶液研究渗透胁迫下玉米幼苗叶片电解质外渗率、丙二醛(MDA)含量和超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)的昼夜变化情况.[结果]一昼夜胁迫中,保护酶活性的变化不仅受PEG浓度和胁迫时间的影响,而且受先照的影响.随着光照时间和胁迫时间的延长,叶片电解质外渗率和MDA含量增加、SOD活性持续降低、POD和CAT活性的变化率则呈先增加后降低趋势;先照结束后,随着黑暗时间的延长,电解质外渗率和保护酶活性先接近对照水平,然后发生较大渡动.[结论]玉米幼苗叶片的保护酶活性变化不仅受PEG浓度、胁迫时间的影响,而且受光照的影响.     

NaCl胁迫对藜幼苗叶片渗透调节物质和保护酶的影响

[目的]研究不同浓度NaCl胁迫对纂叶片中渗透调节物质和保护酶活性的影响,以探讨黎的耐盐机理,为藜的人工栽培及推广提供理论依据.[方法]待藜幼苗长到4叶期时,用0%、0.6%、1.2%、1.8%NaCl溶液进行根部胁迫处理,分别于处理0、1、3、5、7 d后从藜幼苗上部取第3～5片功能叶片进行各项生理指标的测定.[结果]在0.6%Nacl胁迫下,渗透调节物质(可溶糖、脯氨酸和可溶性蛋白质)含量和保护酶(SOD、POD和CAT)活性都是缓慢增加的.丙二醛含量增加不大,膜脂过氧化水平低.在1.2%、1.8%NaCl胁迫下,渗透调节物质(可溶性糖、脯氨酸和可溶性蛋白质)含量随胁迫时间的延长而增加,SOD、POD、CAT活性随胁迫时间的延长先升高后降低,丙二醛含量显著提高,膜脂过氧化水平增大.[结论]藜可以通过渗透调节物质增加和保护酶活性增大来对适度的盐胁迫有一定的适应性,但高浓度、长时间的盐胁迫会对藜造成严重损伤.     

铅胁迫对空心莲子草生长和生理指标的影响

[目的]研究铅胁迫对空心莲子草生长和生理指标的影响,探究重金属铅污染的植物修复方法.[方法]采用不同浓度铅胁迫水培空心莲子草后,观察其外伤症状,并测定其生长指标和生理指标.[结果]随着铅胁迫浓度的增加,空心莲子草生物量和叶绿素含量逐渐降低,茎叶电导率和丙二醛含量持续增加,而SOD,POD和CAT活性则先增加后降低.[结论]当铅浓度不断增加时,空心莲子草茎叶细胞膜透性增大,丙二醛含量高度积累,抗氧化酶系统活力下降,正常氧化代谢受到严重影响,导致植株枯萎.     

铅胁迫对紫萼玉簪幼苗SOD,POD和CAT活性的影响

[目的]研究铅对紫萼玉簪幼苗的毒害机理,为园林植物铅污染的预测预报以及相关修复措施的提出等提供理论依据.[方法]采用温室砂培盆栽试验,通过在盆栽沙子中浇施铅溶液的方法,研究了不同浓度(0、125、250、500、1 000、2 000 mg/kg)外源重金属铅对紫萼玉簪幼苗叶片抗氧化酶的影响.[结果]紫萼玉簪幼苗叶片SOD、CAT活性随铅胁迫浓度的升高呈现先升高后降低的趋势,POD活性随着铅胁迫浓度的增加而逐渐增强,且始终表现出较高的活性.SOD活性在2 000 mg/kg处理下仅为对照的1.55倍;CAT活性在2 000mg/kg处理下达到最低,与对照持平;而POD活性则在2 000 mg/kg处理下达到最大值,是对照的1.72倍.[结论]CAT是对高浓度铅毒害相对敏感的指标,它的敏感性高于POD,也很可能高于SOD.     

铈减轻铅对水稻幼苗毒害的机理初探

通过保护性酶活性及叶绿素、MDA含量的检测,根系活力及电导率测定研究铈减轻水稻幼苗抗重金属铅毒害能力的机理.结果表明,用适宜浓度Ce(NH4)2(NO3)6浸种后培养的幼苗,经重金属铅胁迫后,能有效地降低相对电导率,维持较高的SOD活性,提高POD、CAT活性,减缓MDA的积累.同时,能促进水稻幼苗叶绿素含量及根系活力的提高.     

转炉炉壳热应力分析

根据实际转炉建立实体模型。以有限元为手段,考虑了炉衬和炉壳材料的物性参数随温度变化的特点和炉衬与炉壳之间膨胀间隙,计算了转炉炉壳在温度载荷和炉衬膨胀压力同时作用下的热应力。所得结果可为转炉炉壳设计提供依据。     

焦炭热性能指标意义浅析

通过对焦炭在高炉内的历程及其变化规律的剖析,阐述焦炭热性能指标的意义,形象地把焦炭在高炉内的损耗分为三部分(M1,M2,M3)。指出M2对焦比及焦炭价格有一定的指导作用。     

Results of treatment of cancer of the cardia

Cancer of the cardia is traditionally discussed with cardiac cancer of the lower portion of the esophagus and upper gastric cancer invading the esophagus, and the specific characteristics of cancer of the cardia have never been clearly defined. We reviewed the outcome of 172 patients with adenocarcinoma of the cardia who had undergone radical surgery between 1949 and 1994 in the Division of Gastrointestinal Surgery of the Cancer Institute Hospital. The centers of the tumors were located within 2 cm above and below the boundary between the esophagus and the stomach, and their longitudinal diameter was less than 8 cm. We divided the patients into an early period (1949-1979; n = 79) and a late period (1980-1994; n = 93), and focused on the historical transition. There were no differences in patient gender or histology between the two periods. However, the late period was associated with fewer cases of esophageal invasion and shorter longitudinal diameter, as the age of the population advanced. The number of advanced cancers such as the localized and infiltrative type had decreased, and early cancer and early clinical stage had become more common, but despite the fact that the number of early cancers had increased, extended dissection, such as thoracic and paraaortic lymph node dissection, was performed more frequently. By clinical stage, the long-term outcome markedly improved in Stage I patient in the late period, and tended to improve in Stage II and III patients. This appears to have been attributable to the prevention of micrometastasis by extended dissection, although the number of early cancers is another major potential cause. There were no differences in the outcome of Stage IV patients between the two periods, and further advances in multimodality therapy must be awaited. The range of resection is basically proximal gastrectomy, and if there are adequate indications, the prognosis is favorable. In view of the status of lymphatic flow and lymph node metastasis, and long-term results, lateroaortic lymph node dissection is important. Since the number of early cancer patients has been increasing, if intraabdominal recurrence is prevented, intrathoracic lymph node dissection will contribute greatly to the outcome of such patients.     

The effect of amount of possession of the trait of hostility on accuracy of perception of hostility in others.

Some theories of personality hold that an individual's perception of others is influenced by his own personality characteristics; more specifically, that a trait of low social value will be projected more into others, and that insight into the possession of these characteristics reduces this distortion. These 2 hypotheses were tested by having a group of college students rate each other (including themselves) on degree of friendliness or hostility. Agreement with group rating about self yielded the insight score. In general, the hypotheses were supported; the "friendly" Ss were most accurate in their perception of others, and insight was positively associated with accurate perception. From Psyc Abstracts 36:04:4HL16M. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of rates of infection of two methods of emergency ventricular drainage

The rates of infection of two methods of external ventricular drainage in use at Atkinson Morley's Hospital--namely, (a) percutaneous drainage with Rickham reservoirs and (b) tunnelled ventriculostomies--were compared in this retrospective review. Percutaneous drainage of CSF with Rickham reservoirs was associated with a 27% rate of infection as identified by positive microbiological cultures; tunnelled ventriculostomy catheters had a 10% infection rate. The difference in the infection rate between the two methods was statistically significant (P < 0.015). Other variables examined, including the age and sex of the patients and the reasons for ventricular drainage, were not associated with an increased rate of infection. Most infections from either method were caused by a coagulase negative staphylococcus. The average duration of ventricular drainage before identification of positive cultures was 5.7 days for Rickham reservoirs and 6.0 days for ventriculostomies.     

浅析《野草》的版画特征

鲁迅先生一生热爱美术作品,对版画中木刻兴趣尤甚.<野草>作为其"写心之作",亦呈现出一些与木刻版画一致的审美特征:一是具有木刻版画的色彩特征,多对比、多冷色,有阴郁的美感;二是具有木刻版画的力度特征,环境描写、人物刻画处处刀锋毕现,遒劲有力,有一种"力之美".     

四辊破碎机车刀架的改造

针对四辊破碎机车刀架车削中存在的几个问题,详细介绍了电动车刀架的结构和工作原理,建立主要设计参数的数学表达式,并进行适当的分析。改造后,这种电动车刀架运行平稳、可靠、方便、省力,取得了预期的效果。     

Effect of antibiotics of chemotaxis of human leukocytes

The effect of 20 different antibiotics on chemotaxis by human neutrophils was studied. Human leukocytes incubated with chloramphenicol, rifampin, sodium fusidate, and tetracyclines in vitro showed markedly depressed migration. The mechanisms by which these antibiotics affect leukotaxis are discussed.