Distribution of the 1,25 dihydroxy-vitamin D3 receptor in the bursa of Fabricius of chicken.

The vitamin D3 metabolite 1,25(OH)2D3 is probably involved in B lymphocyte ontogeny. We therefore determined the distribution of the 1,25(OH)2D3 receptor in the bursa of Fabricius and spleen cells of 7-day-old chicks, by immunohistochemistry using a monoclonal antibody against the chick intestinal cell 1,25(OH)2D3 receptor. The bursa cells of young (7-day-old) chicks contained large amounts of receptor while the spleen cells did not. The bursa cells of older (35-day-old) chicks contained fewer receptors, but the number of receptors in the spleen increased.     

Distribution of the 1,25 dihydroxy-vitamin D3 receptor in the bursa of Fabricius of chicken

The vitamin D₃ metabolite 1,25(OH)₂D₃ is probably involved in B lymphocyte ontogeny. We therefore determined the distribution of the 1,25(OH)₂D₃ receptor in the bursa of Fabricius and spleen cells of 7-day-old chicks, by immunohistochemistry using a monoclonal antibody against the chick intestinal cell 1,25(OH)₂D₃ receptor. The bursa cells of young (7-day-old) chicks contained large amounts of receptor while the spleen cells did not. The bursa cells of older (35-day-old) chicks contained fewer receptors, but the number of receptors in the spleen increased.     

Morphology of the intercapsular segment of the oviduct in the golden hamster with special reference to ovumtransit from ruptured follicles to the ampulla

Summary The intercapsular segment of the oviduct in the golden hamster is not a simple duct which has constant outer and inner diameters. After penetrating the bursa ovarica the ICS has a circular constriction and the corresponding oviductal lumen is narrowed.     

Expression of multidrug resistance (mdr) gene(s) in primary lymphoid organs of chicken immune system during embryonic development

The presence of a multidrug resistance (MDR) related protein, P-170, in normal and pathological lymphoid cells has been described. The present report evaluates the expression of themdr 1 gene by using the reverse Polymerase Chain Reaction (PCR) on cells obtained from the thymus and bursa of chicken embryos starting from day 12 until hatching. Results show that the thymic cells are positive from day 12 to the end of the observation period. In contrast,mdr mRNA was detected in the bursa from day 14 to day 17 of embryonic life. Possible relationships between the expression ofmdr and the development of T and B lymphocytes are discussed.     

Endocrine regulation of the bursa copulatrix and receptacle gland ofDanaus plexippus L. (Lepidoptera: Danaidae)

Summary Significant growth occurs in the bursa copulatrix and receptacle glands of female Monarch butterflies held in summer conditions after adult emergence. Removal of the corpora allata prevents this growth, but normal development occurs if juvenile hormone is injected into females lacking corpora allata.     

Changes in the sialic acid content of chick thymus and bursa of Fabricius during age-involution.

The sialic acid content of both thymus and bursa of Fabricius during their growth and involution phases in chick has been reported in this study. It is observed that the sialic acid concentration is very high in 1-week-old chickens. The concentration subsequently decreases to a significant level and rises again prior to the onset of involution. In the post-involution period, a more or less minimal and constant level is maintained. The role of sialic acid in cellular activities of thymo-bursal system has been discussed.     

In vitro morphological characterization of the bursal reticuloepithelial (REp) cells of chicken.

The REp cells of the bursa follicle medulla of chicken were isolated in vitro. Culture of the REp cells was maintained over a period of 10 days and the cells were observed at 3 and 10 days by means of transmission electron microscopy (TEM) and immunofluorescence. The use of an anticytokeratin monoclonal antibody confirmed their epithelial nature. TEM observations showed the presence of desmosomes and tonofilaments, which are characteristic of epithelial cells. Furthermore, to some extent the cells regenerated in vitro the network they form in vivo. Though the growth rate becomes slower with time, the features of the REp cells do not significantly change.     

In vitro morphological characterization of the bursal reticuloepithelial (REp) cells of chicken

Summary The REp cells of the bursa follicle medulla of chicken were isolated in vitro. Culture of the REp cells was maintained over a period of 10 days and the cells were observed at 3 and 10 days by means of transmission electron microscopy (TEM) and immunofluorescence. The use of an anticytokeratin monoclonal antibody confirmed their epithelial nature. TEM observations showed the presence of desmonsomes and tonofilaments, which are characteristic of epithelial cells. Furthermore, to some extent the cells regenerated in vitro the network they form in vivo. Though the growth rate becomes slower with time, the features of the REp cells do not significantly change.     

Changes in the sialic acid content of chick thymus and bursa of Fabricius during age-involution

Summary The sialic acid content of both thymus and bursa of Fabricius during their growth and involution phases in chick has been reported in this study. It is observed that the sialic acid concentration is very high in 1-week-old chickens. The concentration subsequently decreases to a significant level and rises again prior to the onset of involution. In the postinvolution period, a more or less minimal and constant level is maintained. The role of sialic acid in cellular activities of thymo-bursal system has been discussed.Supported by the University Grants Commission, Govt of India under the scheme Support to Research.     

The transfer of juvenile hormone from male to female during mating in the Cecropia silkmoth

Summary The juvenile hormone (JH) stored in the accessory sex glands (ASG) of adult maleHyalophora cecropia (L.) originates both from sequestration of circulating hormone and from JH synthesized de novo in the ASG from JH acid taken up from the hemolymph. The secretions present in the lumina of the ASG contain most of the accumulated JH. During mating, endogenous JH, labeled biosynthetically via injected [³H-methyl]-methionine, is transferred along with the other seminal material to the bursa copulatrix of the female. The physiological significance of the JH transfer remains unknown.Research was supported by a grant from the National Science Foundation (PCM72-01892) and Organized Research Funds from Texas A&M University.This work was done as partial fulfillment for the degree of Doctor of Philosophy.     

Endogenous suppression of pheromone production in virgin female moths

Summary Sexual receptivity generally is reduced in moths after mating. We found that even in virginHeliothis zea females the titer of pheromone declines after the third night of adult life, although the number of eggs laid increases. Reduction in pheromone titer is not due to reduced amounts of pheromone biosynthesis activating neuropeptide. We have discovered that a substance present in the bursa, ovaries and hemolymph of senescing virgins suppresses pheromone production. A similar factor was found in 2-day-old mated females indicating that both virgin and mated females use this factor to suppress pheromone production.     

基于Simulink的装载机行驶平顺性研究

装载机在我国社会主义现代化建设的进程中扮演着越来越重要的角色,其性能的好坏直接影响到工程建设的速度和效率。装载机作业环境比较恶劣,由于工作装置特殊的机械结构,当受到不平路面激励时,工作装置对车架产生猛烈冲击,引发整车的剧烈振动,严重时整车会产生前、后俯仰运动,影响工程车辆的作业效率。本文的研究是针对装载机工作装置的影响下而产生的振动,对整机的振动进行仿真,为提高工程车辆行驶平顺性和操作稳定性提供一定的参考依据。     

安全信息缺失事故致因理论的初步研究

为更好解释事故致因,在分析已有事故致因理论的基础上,分析了安全信息与事故致因因素之间的联系,认为安全信息是各种致因因素的信息化表述,安全信息缺失将直接或间接导致事故的发生并影响事故的发展.继而用安全信息的概念统一人、物、环境、能量和管理等事故致因因素,提出了安全信息缺失的概念和安金信息缺失事故致因理论.新理论认为安全信息缺失是造成事故发生的主要潜在原因,也是导致事故扩大的主要原因,避免关键性安全信息的缺失是预防事故发生和防止事故扩大的重点.建立了新理论的理论模型和可用于定量风险评价的数学模型.该理论为事故有效预防和系统风险评价提供了一种新思路和方法.     

Peirce on the justification of abduction

What sort of justification can be claimed for abduction? In this paper we reconstruct Peirce’s answer to this question. We show that in his early works on the logic of science Peirce provided an abductive justification of abduction, and that in his mature writings the early solution is enriched by a reference to the place abduction has in a typical scientific inquiry. Since abduction is the first stage of inquiry by which a hypothesis is suggested and which then has to be subjected to inductive testing, the fundamental abduction (ur-abduction) that justifies abduction has also to be subjected to a verification by means of a fundamental induction (ur-induction), namely that the abduction that abduction is valid is verified by an appeal to the history of science.     

基于灰色系统模型的城市就业容量预测研究

为解决城市就业容量的预测问题,深入研究了基于灰色系统建模技术的城市就业容量区间灰数预测模型,对模型的模拟误差进行了检验和分析,并将其应用于某市2010～2015就业容量的预测.研究结果对促进劳动力在不同区域的平稳有序流动具有一定的参考价值,对促进灰色系统模型与实际问题的有效对接具有积极意义.     

基于变异系数权重的灰色关联投影法在安全绩效评价中的应用

在提出施工企业安全绩效评价指标体系的基础上,运用灰色关联投影法对企业安全绩效进行评价。为避免指标的相对重要程度因人为赋权的主观性影响和指标权重分配的均衡化以及指标之间因量纲不同而对权重的影响,采取了变异系数法来对各指标确定权重。之后针对实地考察的施工企业进行实证分析,运用比较安全学的思想对安全绩效进行纵向对比,依据评价体系灰色关联度大小来判断施工企业安全绩效的水平高低。进而诊断出各企业安全绩效的优劣,为同类型的企业实际开展安全绩效评价提供指导性的方向和建议。     

基于K-means聚类的快递企业客户细分方法

为了实现对快递企业客户的科学划分,制定差异化的客户营销策略,建立了一种基于K-means聚类的客户细分模型。对快递企业呼叫中心的客户相关数据特征进行了分析与预处理,确定了合理的客户细分变量,并建立了基于呼叫中心数据挖掘的客户细分流程。以某快递企业为例对客户细分方法进行了验证。结果表明该方法能够有效区分快递客户为敏感客户、节俭客户、高端客户、潜在客户与优质客户等五类,为进一步营销方案的设计提供决策支持。     

基于ADAMS／VIBRATION的采煤机截割部振动特性研究

建立了采煤机截割部刚柔耦合虚拟样机的振动模型;利用ADAMS／VIBRATION模块对其振动特性开展了研究;确定了对系统整体性能不利的模态振型和频率,发现截割部电机对系统振动的影响较大;并找出了截割部高速端惰轮轴处轴承失效的主要原因;为有效地抑制采煤机截割部的振动和对其进行局部结构优化提供了理论依据,对全面掌握截割部系统的动态性能具有重要价值。     

Studies on the biochemical effects of glibenclamide on alloxan diabetic rabbits

Treatment of alloxan diabetic rabbits with glibenclamide, the most potent of the sulfonylureas, for a period of 2 months, significantly ameliorated the diabetic condition. It produced a decrease in serum and liver lipids, amino acids, serum urea, blood sugar and urine sugar; increase in body weight, serum and liver proteins, liver glycogen, glucose tolerance and serum and liver acid labile phosphates. The possible mechanism of action of this hypoglycemic agent is discussed.     

化感活性物质影响种子萌发作用机理的研究进展

化感作用由于其独特的生物学特性而受到广泛关注,并逐渐成为近年来的研究热点。然而目前多数的化感作用研究关注于化感物质对幼苗生长的影响以及化感物质的分离、鉴定、提纯,而对化感物质影响植物种子萌发的作用机理缺乏足够的重视。本文主要论述了化感作用的概念、发展以及化感物质降低种子萌发率、改变激素平衡、破坏生物膜结构、影响种子呼吸代谢等一系列生理活动的作用机理。最后对今后化感作用的研究重点进行展望,强调应着重进行化感物质作用机理的精确研究,从分子、基因水平进行探讨。