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961.
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964.
SAAPT-2(1/2)D NC自动编程系统能高效、准确地实现零件源程序到NC程序、NC穿空纸带的转换。该系统由几何处理模块、工艺处理模块、后置处理模块和子程序库组成。几何处理模块对零件源程序几何定义语句进行词法、语法检查和参数标准化计算;工艺处理模块根据标准化参数对运动语句及其它非几何定义语句进行处理,生成中间代码文件;后置处理模块将中间代码文件变成NC加工程序。 相似文献
965.
花生经青枯菌无毒自发突变株AP7接种后,体内过氧化物酶的活性会增高。经无毒自发突变菌株AP7接种后的花生叶片组织粗提液对青枯菌的致病菌株有强烈的体外抑菌作用。将这种粗提液与致病菌株同时注入花生叶片内,亦表现出抑制发病作用,而且这种抑病作用随着粗提液浓度下降而减弱. 相似文献
966.
维生素 C 保护稻叶细胞膜机理的研究 总被引:1,自引:0,他引:1
本文研究了维生素 C 清除超氧自由基(0),保护细胞膜的机理。结果表明;V—C 有清除 O的效应。在清除 O的过程中,有过氧化氢的生成,并且可以经过清除 O而对脂肪酸起到一定的保护作用。同时,V—C 能促进芬顿(Fenton)反应而加快脂肪酸的过氧化破坏作用。用9ppm 的 V—C 喷洒处于40℃和40000lx 条件下的稻叶,能显著降低膜脂过氧化作用和减轻细胞膜的损伤程度。但当喷洒浓度超过9ppm 后,其保护效果减弱。此外,当细胞内 V—C 浓度提高后,过氧化氢酶活性随之增强。 相似文献
967.
亚硒酸钠一次内服在犊牛体内药动学研究 总被引:2,自引:0,他引:2
给犊牛一次内服(0.6mg/kg体重)亚硒酸钠溶液后不同时时间采集血样,用荧光分光光度计测定血硒浓度,在IBM微机上用MCPKP-微机用药动学程序软件处理血硒浓度实测值,微机输出血硒浓度理论值及药动学参数。血硒浓度-时间曲线符合二室开放模型,最佳药时方程为:Ci=0.3602e^-4.6753t+0.4622e^-0.0007t-(0.3602+0.4622)e^-0.1172t.主要动力学参数: 相似文献
968.
Avian rotaviruses present in fecal samples were readily detected using a staphylococcal protein-A coagglutination test on a white porcelain plate. Staphylococci, which produced large amounts of protein-A, were coated with rabbit anti-avian rotavirus serum. The antibody-coated staphylococci were agglutinated specifically by rotavirus present in the fecal sample. The macroscopic agglutination reaction occurred within a few minutes. A total of 40 fecal samples were tested by the coagglutination test. The sensitivity and specificity of the coagglutination test were compared with those of electron microscopy, enzyme-linked immunosorbent assay, and tissue-culture virus-isolation methods. Of the 31 fecal samples positive for rotavirus on electron microscopy, 27 (87%) were positive on coagglutination test. Of the nine electron-microscopy-negative samples, seven (78%) were also negative on coagglutination test. It was concluded that the staphylococcal protein-A coagglutination test can be used as a simple, rapid screening test for avian rotavirus. 相似文献
969.
用不同的低温(2℃、6℃、10℃)处理水稻幼苗后,又于25℃,4000lx 光照下培养3天,分别研究低温期间的“冷效应”和低温后常温期间的“冷后效应”中,起氧物歧化酶(SOD)的活性变化及其与细胞膜损伤的关系,结果表明:低温期间 SOD 活性没有明显变化,脂质过氧化作用不是细胞膜损伤的主要原因。但在冷后效应中,膜脂质过氧化作用增强和 SOD 活性下降与细胞膜损伤有密切关系。同位素示踪表明,SOD 活性下降的主要原因是它的生物合成受阻。 相似文献
970.
AIM: To investigate the effects of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) on the apoptosis, oxidative damage and immune inflammatory factors in myocardial H9c2 cells with anoxia/reoxygenation (A/R). METHODS: The H9c2 cells were used to establish a model of A/R. The H9c2 cells were transfected with PTEN small interfering RNA (siRNA) and negative control. After A/R, the expression of PTEN at mRNA and protein levels was determined by RT-PCR and Western blot, respectively. The cell viability was measured by MTT assay. The apoptosis was analyzed by flow cytometry. Xanthine oxidase method was used to determine superoxide dismutase (SOD) activity. The content of malondialdehyde (MDA) was detected by thiobarbituric acid method. The lactate dehydrogenase (LDH) activity in the supernatant was evaluated by 4-dinitrophenylhydrazine method. The levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and IL-6 in culture supernatant were examined by ELISA. The protein levels of cleaved caspase-3, Bax and FasL in the cells were determined by Western blot. RESULTS: After A/R, the expression of PTEN at mRNA and protein levels was significantly increased in the H9c2 cells (P<0.05). The mRNA and protein levels of PTEN were decreased significantly after transfection with PTEN siRNA (P<0.05). The viability of H9c2 cells was decreased after A/R, while the apoptotic rate was increased. The protein levels of cleaved caspase-3, Bax and FasL were increased in the cells. The MDA level was elevated, the activity of SOD was decreased, and the levels of LDH, TNF-α, IL-1β and IL-6 in the culture supernatant were increased (P<0.05). Down-regulation of PTEN partly antagonized the effects of A/R on the viability, apoptotic rate, MDA content, SOD activity, and the levels of LDH, TNF-α, IL-1β and IL-6 in culture supernatant. CONCLUSION: Down-regulation of PTEN attenuates oxidative damage induced by A/R, reduces apoptosis and secretion levels of TNF-α, IL-1β and IL-6 in the H9c2 cells. 相似文献