二元关系胚的性质及二元关系的胚分解

对于非空集合上的二元关系引入了关系的自反胚,反自反胚,对称胚,反对称胚,等价胚和偏序胚。并讨论了它们的基本性质。而且得到了关系的三个唯一的基本胚分解式。     

Factors influencing the outcome of embryo freezing and thawing program

Objective: To investigate the factors that might influence the success of an embryo freezing and thawing program. Method: The relationship between the pregnancy rate in 73 cycles of embryo, freezing and thawing program and the following factors was analyzed: maternal age,E ₂ level at the time of HCG trigger, embryo storage time, number of thawed embryos transferred, presence of sponsoring embryos and intact embryos. And the survival rate of thawed embryos with different morphology, cell stage and storage time was evaluated. Result: Transfer with three or more than three thawed embryos resulted in pregnancy rates of 38.5% and 35.7%, respectively, compared with 5.3% for transfer of fewer than three embryos. The presence of sponsoring embryos and intact embryos significantly increases pregnancy rate in embryo freezing and thawing program. No other factor examined had any effect on pregnancy outcome. The survival rate of good morphology embryos was higher than poor ones, but was not influenced by cell stage and storage time. Conclusion: Embryo morphology before freezing, number of thawed embryos transferred and the presence of intact embryos are important to the outcome of embryo freezing and thawing program.     

关于人体受精卵和胚胎发育简谈

关于婴儿胚胎的骨骼与肌肉,哪个在先的问题,从19世纪一直争论到20世纪.多数学者认为,应当是骨肉同时发育.在胚胎学领域随着科学技术的发展,通过更先进的显微镜进行的观测研究,证实并阐明了,在母体内首先形成胎儿的骨骼,然后肌肉形成并附着在骨骼上,直至近期还曾认为骨骼与肌肉是同时形成的.即,首先胚胎的软骨组织变为骨骼,然后肌细胞在骨骼周围聚集构成肌肉,并附着在骨骼上.本篇论文中明确地指出了生育的若干阶段,并以简洁易懂的语言解释论述了生育这一生理现象有关的基本知识.     

家畜胚胎移植技术研究历史及应用现状

回顾家畜胚胎移植技术的研究历史 ,介绍胚胎移植的方法 ,并对以胚胎移植技术为基础的现代生物新技术进行了阐述     

萱草胚囊发育的解剖研究

报道了萱草胚囊发育的过程,认为萱草胚囊发育具有典型的四孢子胚囊中贝母型发育特征。