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971.
关瑞明 《华侨大学学报(自然科学版)》1994,15(1):68-72
通过建筑外部空间理论的研究,提出建筑总体设计中的整体意识.以汽车站总体设计为例,阐述N空间的局部P化、锐角空间的钝化、不规则空间的几何化、化整为零等设计方法. 相似文献
972.
申建华 《湖南师范大学自然科学学报》1996,19(3):13-16
研究某类不连续初始函数空间上有限时滞泛函微分方程解的存在唯一性,并应用它来讨论脉冲泛函数微分方程的某些局部理论。 相似文献
973.
厉则治 《厦门大学学报(自然科学版)》1987,(5)
本文证明,取值于收敛复数列Banach空间c的随机元列Vn,不能同时满足EV_n=0,||V_n||≡1及||∑_(i=1)~nV_1/n||≡1.c为收敛实数列空间时,这是Taylor在Stochastic Convergence of Weighted sums of Random Elementsin Linear Spaces,Springer,107面中提出的一个猜想,已被作者解决,并在1986年世界数学家会议上宣读,当时有人问,c能否是收敛复数列空间?本文回答了这个问题. 相似文献
974.
975.
申绍杰 《福州大学学报(自然科学版)》2004,32(6):715-719
从欧氏几何空间,建筑空间的物质属性和空间的时间性3个方面进行论述,从空间概念的由来、空间概念和现代建筑运动的紧密关系、物质材料对空间的直接影响、空间和时间体验等方面出发,展开讨论,对空间概念进行多方位多层次的解析,旨在对被经常论及的"空间"概念进行更深层次的探讨. 相似文献
976.
ZHANGJingpu WANGWeixian ZHUShaoxia 《科学通报(英文版)》2004,49(7):683-688
Interaction between nucleus and cytoplasm has been focused in the field of animal embryonic development, in which study of maternal factors is required positively. β-Catenin, an important maternal factor in early embryogenesis, has been analyzed in its expression pattern and functions in this paper. We have cloned goldfish β-Catenin cDNA gene and compared it with zebrafish β-Catenin cDNA. High homology was found in cDNA and in amino acid sequences between them, 93% (2227/2384 bp) and 98.5% (768/780 aa) respectively. The expression pattern of β-Catenin by in situ hybridization and the roles of β-Catenin on embryonic development by co-injection of anti-sense RNA and reporter gene, EGFP have been investigated in the whole process of goldfish embryonic development. The results suggest that β-Catenin presents dynamic distribution, mainly locates at body axis, dorsal tissues, head and tail structures after being fertilized. The loss of β-Catenin activity would cause serious destruction of embryo in dorsal tissues and in anteroposterior axes, and leads embryos to die before larva get hatched. 相似文献
977.
TIANMing XIONGYuliang WANGWanyu ZHANGYaping 《科学通报(英文版)》2004,49(2):146-152
Both the rhino mouse and hairless mouse resulted from hairless gene mutation, but they show different phenotypes of skin physiology. The rhino mouse has more similar histological characters to human papular alopecia.Therefore rhino mouse is a good experimental animal model for human papular alopecia. This study reports a hairless mouse named rhino KIZ, arose from KM colony in Kunming Institue of Zoology, by systematic studies on morphology,skin histopathology, gene sequence, pedigree and protein domain analysis. The results demonstrate that a C-to-T transition in exon 11 of hr gene (The mutant gene has been applied for a Chinese patent (patent No. 03135280)) results in the rhino KIZ. The rhino KIZ with clear genetic mechanism will be a useful animal model. 相似文献
978.
Caffeine as a psychomotor stimulant: mechanism of action 总被引:10,自引:0,他引:10
The popularity of caffeine as a psychoactive drug is due to its stimulant properties, which depend on its ability to reduce adenosine transmission in the brain. Adenosine A1 and A2A receptors are expressed in the basal ganglia, a group of structures involved in various aspects of motor control. Caffeine acts as an antagonist to both types of receptors. Increasing evidence indicates that the psychomotor stimulant effect of caffeine is generated by affecting a particular group of projection neurons located in the striatum, the main receiving area of the basal ganglia. These cells express high levels of adenosine A2A receptors, which are involved in various intracellular processes, including the expression of immediate early genes and regulation of the dopamine- and cyclic AMP-regulated 32-kDa phosphoprotein DARPP-32. The present review focuses on the effects of caffeine on striatal signal transduction and on their involvement in caffeine-mediated motor stimulation.Received 8 July 2003; received after revision 7 September 2003; accepted 6 October 2003 相似文献
979.
-Amylases are present in all kingdoms of the living world. Despite strong conservation of the tertiary structure, only a few amino acids are conserved in interkingdom comparisons. Animal -amylases are characterized by several typical motifs and biochemical properties. A few cases of such -amylases have been previously reported in some eubacterial species. We screened the bacterial genomes available in the sequence databases for new occurrences of animal-like -amylases. Three novel cases were found, which belong to unrelated bacterial phyla: Chloroflexus aurantiacus, Microbulbifer degradans, and Thermobifida fusca. All the animal-like -amylases in Bacteria probably result from repeated horizontal gene transfer from animals. The M. degradans genome also contains bacterial-type and plant-type -amylases in addition to the animal-type one. Thus, this species exhibits -amylases of animal, plant, and bacterial origins. Moreover, the similarities in the extra C-terminal domains (different from both the -amylase domain C and the starch-binding domain), when present, also suggest interkingdom as well as intragenomic shuffling.Received 17 October 2003; accepted 6 November 2003 相似文献
980.
Sex determination and gametogenesis are key processes in human reproduction, and any defect can lead to
infertility. We describe here the molecular mechanisms of male sex determination and testis formation; defects in
sex determination lead to a female phenotype despite the presence of a Y chromosome, more rarely to a male
phenotype with XX chromosomes, or to intersex phenotypes. Interestingly, these phenotypes are often associated
with other developmental malformations. In testis, spermatozoa are produced from renewable stem cells in a complex
differentiation process called spermatogenesis. Gene expression during spermatogenesis differs to a surprising
degree from gene expression in somatic cells, and we discuss here mechanistic differences and their effect on the
differentiation process and male fertility.Received 23 January 2004; received after revision 30 March 2004; accepted 6 April 2004 相似文献