Altering conception of dairy cattle by gonadotropin-releasing hormone preceding luteolysis induced by prostaglandin F2 alpha

The objective of these experiments was to determine the effect on fertility of GnRH when used in conjunction with one or two injections of PGF2alpha. In Experiment 1, GnRH was administered 7 d before the second of two injections of PGF2alpha (14 d apart). The control group received two injections of PGF2alpha without GnRH. Conception was reduced from 63.5% for 74 controls to 48.7% for the 79 heifers and cows that had been treated with GnRH, but estrus detection and pregnancy rates were similar. In Experiment 2, 85 heifers and cows received GnRH at a random stage of the estrous cycle, followed in 7 d by PGF2alpha. Thirty to 32 h after PGF2alpha, a second dose of GnRH was given to induce ovulation of the preovulatory follicle, followed by one fixed-time insemination 18 to 19 h later (treatment designated as GnRH, PGF2alpha, and GnRH). Controls (n = 85) were given PGF2alpha and inseminated at estrus. Although conception rate was not different, one fixed-time insemination after the GnRH, PGF2alpha, and GnRH treatment tended (35.3%) to reduce fertility compared with effects of the control (47.1%). It is unclear how an injection of GnRH during the intervening week between two injections of PGF2alpha reduced fertility in Experiment 1. However, in Experiment 2, when GnRH was given 7 d before one injection of PGF2alpha and when ovulation was induced with a second GnRH injection, one fixed-time insemination seemed to produce acceptable fertility in dairy cows but probably less than that when inseminations were based on detected estrus.     

Characterisation of a metallic foam–cement composite under selected loading conditions

An open-cell metallic foam was employed as an analogue material for human trabecular bone to interface with polymethyl methacrylate (PMMA) bone cement to produce composite foam–cement interface specimens. The stress-displacement curves of the specimens were obtained experimentally under tension, shear, mixed tension and shear (mixed-mode), and step-wise compression loadings. In addition, under step-wise compression, an image-guided failure assessment (IGFA) was used to monitor the evolution of micro-damage of the interface. Microcomputed tomography (µCT) images were used to build a subject-specific model, which was then used to perform finite element (FE) analysis under tension, shear and compression. For tension–shear loading conditions, the strengths of the interface specimens were found to increase with the increase of the loading angle reaching the maximum under shear loading condition, and the results compare reasonably well with those from bone–cement interface. Under compression, however, the mechanical strength measured from the foam–cement interface is much lower than that from bone–cement interface. Furthermore, load transfer between the foam and the cement appears to be poor under both tension and compression, hence the use of the foam should be discouraged as a bone analogue material for cement fixation studies in joint replacements.     

A Simple Control System for Current Source Inverter-Fed Induction Motor Drives

A simple control system for induction motor drives with the current source inverter is presented. This system is based on the idea of field-orientated control. In contrast to well-known ways of realization a torque proportional quantity is calculated from stator voltage and current without explicit flux calculation or integration. A speed sensor is not required. The theoretical principles of this method are discussed. Some transients which illustrate the performance of some different system variants are presented.     

鄂尔多斯盆地三叠系镜质体反射率与地热史

鄂尔多斯盆地庆36井三叠系镜质体反射率为0.61%～1.06%,其碳化梯度(R_m/km)较高,达0.36%.运用不同方法分析表明,该盆地中生代古地温梯度可达35～57℃/km,高于现今地温梯度.其它地温分析结果支持这一推论.推测高古地温梯度的原因可能是中生代时地壳厚度较薄和中侏罗世末一期热事件.讨论了高古地温梯度对于油气形成与勘探的影响.     

流程泵的节能方案 节能泵技术能够帮助流程工业企业获得很好的经济效益

近两年以来,关于泵产品节能情况的调查对企业进行了全面准确的现场诊断和分析,50多家来自化工和制药生产领域的企业在专家建议的基础上对各自流程设备中的流程泵进行了能源利用优化,基本都获得了令人满意的节能效果。     

论基于不同工业通讯协议的CPU数据访问方式

在提出工业实时网络传输批量数据“瓶颈”论题的基础上，研讨如何选用灵活多样的netX控制器接口来满足不同的工业通讯系统的不同需求。     

Thresholds of Endoglin Expression in Endothelial Cells Explains Vascular Etiology in Hereditary Hemorrhagic Telangiectasia Type 1

Hereditary Hemorrhagic Telangiectasia type 1 (HHT1) is an autosomal dominant inherited disease characterized by arteriovenous malformations and hemorrhage. HHT1 is caused by mutations in ENDOGLIN, which encodes an ancillary receptor for Transforming Growth Factor-β/Bone Morphogenetic Protein-9 expressed in all vascular endothelial cells. Haploinsufficiency is widely accepted as the underlying mechanism for HHT1. However, it remains intriguing that only some, but not all, vascular beds are affected, as these causal gene mutations are present in vasculature throughout the body. Here, we have examined the endoglin expression levels in the blood vessels of multiple organs in mice and in humans. We found a positive correlation between low basal levels of endoglin and the general prevalence of clinical manifestations in selected organs. Endoglin was found to be particularly low in the skin, the earliest site of vascular lesions in HHT1, and even undetectable in the arteries and capillaries of heterozygous endoglin mice. Endoglin levels did not appear to be associated with organ-specific vascular functions. Instead, our data revealed a critical endoglin threshold compatible with the haploinsufficiency model, below which endothelial cells independent of their tissue of origin exhibited abnormal responses to Vascular Endothelial Growth Factor. Our results support the development of drugs promoting endoglin expression as potentially protective.     

BMP Receptor Inhibition Enhances Tissue Repair in Endoglin Heterozygous Mice

Hereditary hemorrhagic telangiectasia type 1 (HHT1) is a severe vascular disorder caused by mutations in the TGFβ/BMP co-receptor endoglin. Endoglin haploinsufficiency results in vascular malformations and impaired neoangiogenesis. Furthermore, HHT1 patients display an impaired immune response. To date it is not fully understood how endoglin haploinsufficient immune cells contribute to HHT1 pathology. Therefore, we investigated the immune response during tissue repair in Eng+/− mice, a model for HHT1. Eng+/− mice exhibited prolonged infiltration of macrophages after experimentally induced myocardial infarction. Moreover, there was an increased number of inflammatory M1-like macrophages (Ly6C^high/CD206⁻) at the expense of reparative M2-like macrophages (Ly6C^low/CD206⁺). Interestingly, HHT1 patients also showed an increased number of inflammatory macrophages. In vitro analysis revealed that TGFβ-induced differentiation of Eng+/− monocytes into M2-like macrophages was blunted. Inhibiting BMP signaling by treating monocytes with LDN-193189 normalized their differentiation. Finally, LDN treatment improved heart function after MI and enhanced vascularization in both wild type and Eng+/− mice. The beneficial effect of LDN was also observed in the hind limb ischemia model. While blood flow recovery was hampered in vehicle-treated animals, LDN treatment improved tissue perfusion recovery in Eng+/− mice. In conclusion, BMPR kinase inhibition restored HHT1 macrophage imbalance in vitro and improved tissue repair after ischemic injury in Eng+/− mice.     

Effective incorporation of ZnO nanoparticles by miniemulsion polymerization in waterborne binders for steel corrosion protection

A nanohybrid waterborne binder was synthesized by miniemulsion polymerization with the incorporation of ZnO nanoparticles in order to increase the corrosion protection capability. This system was compared to a neat waterborne binder and to a physical blend of the binder with an aqueous ZnO nanoparticles dispersion. The hybrid dispersion was characterized by SEM and TEM, while the corrosion behavior of these latexes was investigated by electrochemical measurements (open circuit potential and electrochemical impedance spectroscopy in 3.5 wt% NaCl solution), evaluating the effect of the incorporation of these nanoparticles into the polymeric matrix. The incorporation of ZnO nanoparticles by blending showed similar behavior to the neat coating despite flash rust reduction on the metal surface. In contrast, the hybrid binder prepared by miniemulsion polymerization has shown the best performance according to the values of pore resistance (R _i ) and coating capacitance (C _c). In general, this study shows how useful can be the miniemulsion polymerization methodology to design hybrid coating formulations, obtaining homogenous distribution of ZnO nanoparticles within the film. Indeed, a heterogeneous distribution can hinder the effectiveness and the corrosion protection capabilities of promising nanoparticles.