Spermatogenesis in man: an estimate of its duration

Testicular biopsies were obtained at various intervals after intratesticular injections of tritiated thymidine. Radioautographs revealed that the most mature labeled germ cells were the preleptotene spermatocytes at 1 hour, the midpachytene spermatocytes at 16 days, and the immature spermatids at 32 days after injection. These results indicated that one cycle of the seminiferous epithelium lasts 16 days, and the whole of spermatogenesis is estimated to consume approximately 64 days.     

Growth-hormone deficiency in man: an isolated, recessively inherited defect

A deficiency of human growth hormone not associated with other pituitary deficiencies was observed in midgets with sexual ateliosis, a form of dwarfism inherited as an autosomal recessive trait. Body proportions, sexual development, birth weight, and postpartum lactation are normal in this syndrome.     

对马克思早期哲学的总体评述

马克思主义哲学是时代精神的精华，是无产阶级争取自身和全人类解放的科学世界观和方法论，是科学性和革命性相统一的哲学学说。做为马克思主义哲学的创始人——马克思，在马克思主义哲学的形成中起着重要的主导作用。在对马克思主义哲学问题的研究中，对马克思本人哲学思想的研究也是不可缺少的重要内容。     

Steroid 5alpha-reductase deficiency in man: an inherited form of male pseudohermaphroditism

In male pseudohermaphrodites born with ambiguity of the external genitalia but with marked virilization at puberty, biochemical evaluation reveals a marked decrease in plasma dihydrotestosterone secondary to a decrease in steroid 5alpha-reductase activity. In utero the decrease in dihydrotestosterone results in incomplete masculinization of the external genitalia. Inheritance is autosomal recessive.     

Erratum: wrong man

In my letter in the issue of 24 December ("Looking ahead," p. 1667), I erroneously made Klement Gottwald, instead of Walter Ulbricht, the protagonist of "a story popular in Germany (East and West) during the 1950's." I am indebted to Károly Balogh for reminding me that Gottwald was Ulbricht's Czech counterpart.     

Max Born's Statistical Interpretation of Quantum Mechanics

In the summer of 1926, a statistical element was introduced for the first time in the fundamental laws of physics in two papers by Born. After a brief account of Born's earlier involvements with quantum physics, including his bringing the new mechanics to the United States, the motivation for and contents of Born's two papers are discussed. The reaction of his colleagues is described.     

立桶式家用热泵热水器冷凝器性能的研究

针对华南地区的气候特点,用同样管径和长度的高导热耐腐蚀不锈钢管绕成等径螺旋盘管和非等径螺旋盘管作为家用热泵热水器的沉浸式冷凝器,并对其传热特性进行了对比分析和实验研究.结果表明,在同等环境条件下,加热90 L立桶式静态水至50℃,非等径螺旋盘管的综合效果优于等径螺旋盘管;加热3 L/min流量的立桶式动态水,采用非等径螺旋盘管的平均出水温度比等径螺旋盘管大约高1℃.     

大豆油体蛋白基因家族的生物信息学分析

油体蛋白(oleosin)是植物中的一类贮藏蛋白,主要作用是维持油体的稳定和贮藏脂质.通过生物信息学方法,对大豆油体蛋白(Glycine max oleosin,Gmole)基因家族中12个成员(编号Gmole1 ～ Gmole 12)的理化性质、结构特点等进行预测分析并建立进化树.结果 表明:12个成员分布在大豆的8...