筒式结构拆除的力学分析

根据力学原理，分析讨论了钢筋混凝土筒式结构定向倾倒的切口高度和切口角度．     

Systemic and pulmonary antibody responses of calves to Pasteurella haemolytica after intrapulmonary inoculation.

Systemic and pulmonary antibody responses of calves to Pasteurella haemolytica were evaluated by measuring immunoglobulin production in blood for 9 days and in pulmonary lavage fluid for 7 days after intrapulmonary inoculation. Clinical signs, pulmonary lesions, pulmonary and systemic inflammatory response, and amount of antigen in lavage fluid were used to evaluate the response of calves to challenge with P haemolytica. The pulmonary response consisted of production of IgG, IgE, and IgM antibodies to P haemolytica antigens and a 17- to 68-fold increase of cells in lavage fluid 8 hours after inoculation, with a gradual decrease toward normal. Antibodies of the IgM isotype to P haemolytica were demonstrated as early as 8 hours through 7 days after inoculation in 3 of 3 calves. Of the anti-P haemolytica isotypes, IgM was found in the highest concentration. In all of the inoculated calves, IgE was found 1 to 2 days after inoculation, and IgG was found in 2 of 3 inoculated calves from day 1 through 7 after inoculation. Detection of IgG correlated with smaller pulmonary lesions. Immunoglobulin A was not detected in lavage fluid. Serum was evaluated for IgG and IgM antibody response to P haemolytica. Specific IgM was detectable 5 days after inoculation, and IgG was detectable 7 days after inoculation. Pasteurella haemolytica antigens were not detected in serum or plasma. A transient increase in neutrophil count was found 8 hours after inoculation, with return to baseline values by 24 hours after inoculation.(ABSTRACT TRUNCATED AT 250 WORDS)     

5-bromo-2'-deoxyuridine blocks myogenesis by extinguishing expression of MyoD1

The pyrimidine analog 5-bromodeoxyuridine (BUdR) competes with thymidine for incorporation into DNA. Substitution of BUdR for thymidine does not significantly affect cell viability but does block cell differentiation in many different lineages. BUdR substitution in a mouse myoblast line blocked myogenic differentiation and extinguished the expression of the myogenic determination gene MyoD1. Forced expression of MyoD1 from a transfected expression vector in a BUdR-substituted myoblast overcame the block to differentiation imposed by BUdR. Activation of BUdR-substituted muscle structural genes and apparently normal differentiation were observed in transfected myoblasts. This shows that BUdR blocks myogenesis at the level of a myogenic regulatory gene, possibly MyoD1, not by directly inhibiting the activation of muscle structural genes. It is consistent with the idea that BUdR selectively blocks a class of regulatory genes, each member of which is important for the development of a different cell lineage.     

强力增产素对小麦花后干物质生产和产量的调节效应

试验于１９９０～１９９２年在江苏农学院实验农场进行，供试品种（系）为扬麦５号、冀８４５４１８和８８７４．通过在小麦开花期喷施强力增产素，研究其对小麦花后干物质生产和产量的影响。结果表明：喷施强力增产素能延缓花后叶片的衰老，提高叶片叶绿素含量，增强光合功能，扩大花后干物质积累量，具有一定的增粒、增重作用。开花期喷施，可增产６．８２％～８．５６％，花后２０ｄ喷施效应下降，仅增产３．７３％。     

Studies on feasibility of producing Salmonella-free turkeys

The feasibility of producing salmonella-free turkeys was investigated over a 5-year period. In Phase 1, a hatchery-breeder flock operation was monitored extensively for 4 years. Hatching eggs from a primary breeder over this period (1978-81) resulted in salmonella-free day-old poults from which 7500 hens and 600 tons were selected for breeders each of the 4 years. Approximately 2.5 million poults were produced over the 4 years. Salmonella arizonae was isolated from the hatchery debris over a 2-week period in 1980. The pelleted feed contained no animal protein products except fish solubles. A sample of feed from each delivery was cultured with no salmonella isolations. Environmental samples of dust and litter remained negative for salmonella. Phase 2 involved monitoring seven grow-out flocks initiated with salmonella-free poults with extra precautions directed at the feed and environment. The intestinal tracts of five of seven flocks at the time of marketing were negative for salmonella. Phase 3 involved a primary breeder-hatchery that had a 10-year history of S. sandiego infection in its breeder flocks and poults. A vaccination program using an autogenous oil-adjuvant bacterin supplementing other sanitation and management efforts resulted in elimination of S. sandiego. Because the breeder went out of business, it was not possible to determine if the freedom from salmonella could be sustained over a period of years.     

市场经济条件下如何加强林业的基础地位

市场经济条件下如何加强林业的基础地位是关系到国民经济可持续发展的关键所在。当前我国林业基础环境、林业政策环境和投资环境存在一些问题 ,林业走向市场也存在困难 (分类经营问题、林业产业的弱质性问题等 )。通过系统实施林业分类经营、制定林业保护政策、建立和完善森林生态效益补偿制度、实施森林资源强制保险、加强宏观调控建立活立木市场等 6项对策来加强林业基础地位。     

葡萄二倍体与四倍体品种间杂交胚珠的离体培养

为了克服葡萄二倍体品种与四倍体品种之间的交配障碍,进行了杂交胚珠的离体培养研究。发芽胚珠的取样时期集中于授粉后35～75d,其中多数以二倍体作母本的组合在授粉后55d取样的发芽率最高,以四倍体作母本的组合授粉后70d取样的发芽率最高。基本培养模式为:发育培养基-(剥胚)萌发培养基-生长培养基。用二倍体品种作母本时,所有组合均获得了培养苗,在1号培养基上培养的胚珠发芽率高于2号培养基。反交对培养基的要求有相反趋势,其中2个组合未得到培养苗。授粉后60d,直接剥出杂种胚进行培养,得到了最高发芽率。综合分析初步认为,用二倍体品种作母本比用四倍体品种作母本容易获得杂交后代。     

Lactate Kinetics in veterinary Critical Care: A Review

Elevation in blood lactate concentration, with or without accompanying metabolic acidosis, is a hallmark finding in patients with circulatory compromise, and is also consistently noted in other conditions affecting critically ill or injured individuals. Little is reported in a veterinary literature regarding lactate measurement in the emergency and critical care setting, despite impressive reports of the clinical usefulness of lactate measurement in people. The purpose of this article is to review lactate kinetics and the clinical utility of lactate measurement. Limitations to lactate evaluation will also be discussed.