排序方式: 共有75条查询结果,搜索用时 15 毫秒
31.
用GITC手性试剂衍生化高效液相色谱法拆分β-氨基醇类药物对映体 总被引:1,自引:0,他引:1
近十年来,用手性高效液相色谱拆分对映体化合物的技术已得到飞速发展。新型的手性固定相和手性流动相不断出现,种类繁多。但作为最早发展起来的柱前手性衍生化方法,由于采用普通的色谱系统进行拆分,有简便、易行的特殊优点,而仍被广泛应用。 相似文献
32.
33.
34.
为探讨构效关系,合成了1-对氟苯基-6-氟-1,4-二氢-4-氧-7-(1-哌嗪)噌啉-3-羧酸及其喹啉、萘啶、吡啶[2,3-C]哒嗪环系类似物16个。测定了对大肠杆菌的MIC。用Hückel分子轨道理论(HMO)方法计算了四个母体环上电子密度。结果表明:环中氮的位置对药效团——3位羧基和4位羰基氧原子上电子密度的影响较大而影响其抗菌活性。喹啉、萘啶两环系的3位羧基和4位羰基氧原子上的电子密度较高,其体外抗菌活性较高;而噌啉及吡啶[2,3-C]哒嗪两环系的电子密度较低,其体外抗菌活性较低甚至消失。 相似文献
35.
36.
Van de Velde H; Nagy ZP; Joris H; De Vos A; Van Steirteghem AC 《Human reproduction (Oxford, England)》1997,12(10):2246-2250
The aim of this study was to compare concentrations of hyaluronidase and
mechanical methods used to denude human oocytes from surrounding cumulus
and corona cells prior to intracytoplasmic sperm injection (ICSI). Cumulus
and corona cells were removed in two pipetting steps: first in a medium
containing hyaluronidase, and then in a medium without enzyme. The first
step in the procedure was investigated. Different hyaluronidase
concentrations (78, 39 or 10 IU/ml) and pipettes of different size (inner
diameter 250 or > 1000 microm) were used to remove the cumulus cells.
The time required to denude the oocytes was recorded. Metaphase II oocytes
were injected, and the survival, fertilization, embryo development and
pregnancy rates were evaluated. We found that by using a pipette with an
inner diameter of at least 1000 microm we were able to decrease
significantly the time an oocyte is exposed to hyaluronidase, even if the
concentration of enzyme is very low (10 IU/ml). For the different
conditions there was no statistically significant effect on the outcome in
terms of survival, normal fertilization [two pronuclear (2PN)],
parthenogenetic activation (1PN), abnormal fertilization (3PN), embryo
development and pregnancy rates after ICSI. In conclusion, a concentration
as low as 10 IU/ml hyaluronidase in combination with a pipette of at least
1000 microm inner diameter can be used successfully to denude oocytes for
microinjection.
相似文献
37.
复张性肺水肿153例 总被引:5,自引:0,他引:5
0引言.复张性肺水肿(reexPanslonPulmonaryedemaRPE)是指继发于各种原因所致的肺萎陷在肺迅速复张后所发生的急性肺水肿,多见于气、液胸患者经大量排气排液之后.我们于1980~1997年间共收治153例肺萎陷患者,其中自发性气胸121例,胸腔积液32例.治疗过程中,前者有6例、后者有1例发生了RPE.现对之加以总结和讨论.回临床资料和方法121例自发性气胸中,男性90例,女性31例,年龄15岁~74岁,17例行胸腔穿刺抽气,104例行胸腔闭式引流,其中67例加负压吸引.32例胸腔积液中,男性18例,女性14例,年龄18岁~78岁,27例行胸腔穿刺抽… 相似文献
38.
39.
40.