Edrawing在启动机产品演示中的应用

以启动机为例,介绍利用Solidworks下的插件Edraw ing实现启动机结构和动画演示的有效方法,重点分析了An im ator下爆炸动画和运动模拟动画的实现,以及利用Edraw ing制作演示软件和对演示软件进行操作的过程,使启动机的产品宣传和方案论证更加形象直观。     

Modeling the effects of estradiol and progesterone on the acute phase proinflammatory axis: variability in tumor necrosis factor-α, nitric oxide, and xanthine oxidase responses to endotoxin challenge in steers

The severity of host response in some diseases differs between sexes, and this dimorphism has been attributed to the immunomodulating effects of reproductive steroid hormones. In females, susceptibility to disease stress has been associated with reproductive status and attributed to prevailing progesterone (P4) or estrogen concentrations during different estrous cycle phases. Our objective was to clarify and define the effect of P4 or 17β-estradiol (E2) on the acute proinflammatory component of the innate immune system by administering these hormones to steers and evaluating initial and tolerance-associated concentration patterns of circulating proinflammatory immune response mediators after two consecutive lipopolysaccharide (LPS) challenges (LPS1 and LPS2, 6 d apart; 2.5 μg/kg BW, intravenously, Escherichia coli 055:B5). Plasma concentrations of the proinflammatory initiation cytokine tumor necrosis factor-α (TNF-α), nitrate+nitrite [NO(x), estimate of nitric oxide (NO) production], haptoglobin (HG; acute phase protein) and plasma xanthine oxidase activity (mediator of superoxide production) were measured. Crossbred steers (392 ± 7 kg) were fed a forage-concentrate diet (15% CP) to appetite and assigned to control (C; n = 7), P4 (n = 8), or E2 (n = 5) treatment. Jugular blood samples were obtained at 0, 1, 2, 3, 4, 7, and 24 h relative to each of the two LPS injections. For each proinflammatory biomarker, the area under the time by concentration curve (AUC) was used to evaluate and compare responses to the LPS challenge. Treatment with E2 disrupted LPS tolerance as observed in augmented plasma TNF-α (P < 0.01) and NO(x) (P < 0.01) responses to LPS2. Compared with C, P4 treatment decreased plasma NO(x) AUC after LPS2 (P < 0.05) and tended to reduce TNF-α AUC after LPS1 (P = 0.08). Plasma xanthine oxidase activity AUC was increased (P < 0.01) over C by E2 treatment after both LPS1 and LPS2. HG response to LPS1 within 24 h was not affected by any treatment. However, 6 d after LPS1 plasma HG concentration remained higher (P < 0.01) in steers treated with E2 than with C or P4. Results indicate that in cattle, P4 and E2, respectively, attenuate or amplify the response to LPS challenge at several points critical to the regulation of the progression of the proinflammatory cascade.     

Ovarian steroids modulate tumor necrosis factor-α and nitric oxide-regulated prostaglandin secretion by cultured bovine oviductal epithelial cells

Ovarian steroids assure an optimum environment for the final maturation of oocytes, gamete transport, fertilization, and early embryonic development. The aim of experiment 1 was to examine the influence of ovarian steroids on tumor necrosis factor-α (TNF-α)- or nitric oxide (NO)-regulated prostaglandin (PG), and nitrite/nitrate (NO₂/NO₃) secretion by cultured bovine oviductal epithelial cells (BOECs). BOECs were pretreated with 17β-estradiol (E₂; 10⁻⁹ M) and/or progesterone (P₄; 10⁻⁷ M) for 24 h. For the next 24 h, BOECs were treated with TNF-α (10 ng/mL) or spermine nitric oxide complex (NONOate; 10⁻⁵ M). Prostaglandin F_2α and PGE₂ secretion was measured in medium by ELISA. The pretreatment of cells with P₄ (progesterone), E₂ (17 β-estradiol), or E₂/P₄ augmented TNF-α-induced PGF_2α and PGE₂ secretion (P < 0.01). The pretreatment of cells with E₂ or E₂/P₄ increased NONOate-induced PGF_2α and PGE₂ secretion (P < 0.01). TNF-α induced NO₂/NO₃ production by BOECs. The pretreatment of cells with E₂ augmented only TNF-α-induced NO₂/NO₃ production (P < 0.05). The aim of experiment 2 was to examine the influence of TNF-α, NO, and ovarian steroids on the protein content of enzymes specifically involved in PG and NO production, PG synthases, and NO synthases (NOSs). BOECs were treated with TNF-α (10 ng/mL) or NONOate (10⁻⁵ M). TNF-α increased the protein content of PGG/H synthase, PGF synthase, and PGE synthase (P < 0.05) and endothelial and inducible NOSs (P < 0.05). Nitric oxide increased the protein content of PGF synthase, PGE synthase, endothelial NOS, and inducible NOS (P < 0.05). These results show possible linkage between TNF-α and NO, modulated by ovarian steroids, in the regulation of PG synthesis by BOECs that may be important for triggering the process of oviductal contractions.     

Antimicrobial activity of gallium nitrate against Mycobacterium avium subsp. paratuberculosis in neonatal calves

Background: Mycobacterium avium subsp. paratuberculosis (MAP), the agent of Johne's disease in cattle, is a facultative intracellular bacterium that is dependent on ferric iron for its survival and replication. Gallium (Ga), a trivalent semimetal that shares many similarities with ferric iron and functions as an iron mimic has been shown to have in vitro antimicrobial activity against several microorganisms, including MAP. Objectives: (1) To investigate the antimicrobial activity of Ga in calves experimentally infected with MAP; and (2) to monitor for potential adverse effects of Ga on calf health. Animals: Twelve Holstein calves. Methods: Randomized blind controlled experiment. Beginning at 10 days of age (study day 1), the experimental calves (n = 6) were treated with 20 mg/kg gallium nitrate daily for 45 days. On study days 4 and 5, all calves were challenged with a PO dose of a live field strain MAP. Treated calves were monitored daily for adverse effects. Calves were euthanized on study day 100, and 29 tissue samples and 1 fecal sample were collected from each calf. Samples were cultured for MAP by MGIT liquid culture system, Herrold's Egg Yolk Medium culture, or both. Results: No adverse effects were observed in the treated calves. Treatment was associated with a significant reduction in MAP tissue burden when compared with control calves (P = .017). Conclusions and Clinical Relevance: Chemoprophylactic treatment of calves with Ga before and during the period of high susceptibility decreased MAP tissue colonization in experimentally infected neonatal calves.     

文山黄牛品种简介

就文山黄牛的分布、品种特性、适应性、杭病力、生产性能等进行了详细的介绍.     

安西牛品种资源调查及保种对策

本文介绍了安西牛生存的自然环境、品种来源、外貌特征、生产性能和发展中存在的问题;对安西牛保护、利用提出了保种对策,对全面认识和开发利用这一优良品种奠定了基础.     

不同放牧强度对环湖地区高寒草原地上净初级生产量与再生量的影响

通过放牧实验探讨放牧强度对环湖地区高寒草原地上净初级生产量与再生量的影响。结果表明：①不同放牧强度下牧草的总净初级生产量在2.29只/hm2的放牧强度下出现最大值232.01g/m^2,各放牧小区的净初级生产量均小于对照区,不存在超补偿性生长,极重放牧与对照的差异显著（P〈0.05）;②牧草生长季节地上净初级生产量随放牧强度的增加呈先增后减的趋势,而且极重放牧（4.01只/hm^2）条件下地上净初级生产量最大值的形成日期提前出现;③适宜的放牧强度有利于增加牧草的再生量,在放牧强度为2.29只/hm^2时牧草再生量达到最大。     

饲用微生物在反刍动物中应用的研究进展

本文旨在讨论饲用微生物的分类,调控瘤胃的作用机制,以及在反刍动物生产中的应用现状,阐述饲用微生物在反刍动物应用的安全性和促进反刍动物生产性能的有效性,为反刍动物的健康生产提供理论指导和现实依据。     

集成配套技术对肉牛生产能力的促进作用调查

[目的]为了综合评价支撑平凉牛产业发展的集成配套技术应用效果。[方法]采取随机跟踪调查和现场测定的方法,对生长发育跟踪调查和肉用性能测定,进行比较分析。[结果]平凉红牛各月龄体重均提高10%以上;10-24月龄日增重达663.1 g,提高10.55%;胴体重、净肉重分别提高16.16%和13.73%;屠宰率、净肉率分别提高2.52和1.17个百分点;高档肉块重达23.00 kg,增加2.98 kg,可增加经济效益357.6元。[结论]通过普及应用集成配套技术,饲养的肉牛生长发育和肉用性能明显改善,肉牛个体生产能力提高10%以上,经济效益显著增加。