Interaction between dietary protein and fat in triglyceride metabolism in the rat: Effects of soy protein and menhaden oil

The objective of the present study was to determine the mechanisms by which dietary proteins interact with dietary lipids in the regulation of triglyceridemia in rats. Male Sprague-Dawley rats (n=56) were subjected to 28-d experimental diets containing different combinations of proteins (20% w/w) and lipid sources (14% w/w): (i) casein-menhaden oil, (ii) casein-beef tallow, (iii) soy protein-menhaden oil, and (iv) soy protein-beef tallow. Significant protein-lipid interactions were observed on triglyceridemia and hepatic cholesterol in fasted rats. The combination of casein and beef tallow was associated with high plasma TG and hepatic cholesterol concentrations, which were reduced by substitution either of soy for casein or of menhaden oil for beef tallow. Therefore, triglyceridemia and liver cholesterol remained low with soy protein feeding, independently of the lipid source, as well as with menhaden oil feeding, regardless of the protein source. The menhaden oil diets reduced plasma cholesterol, hepatic TG, and TG secretion compared with beef tallow diets independently of the dietary protein source. Modifying the source of dietary proteins and lipids had no effect on post-heparin plasma lipoprotein lipase activity. These results demonstrate that soy protein can lower rat triglyceridemia relative to casein when associated with beef tallow consumption, whereas menhaden oil can attenuate hypertriglyceridemia when rats are fed casein. The data further suggest that part of the hypotriglyceridemic effect of soy protein in the rat may be mediated by reduced hepatic lipid synthesis, as is the case for menhaden oil.     

湖北黄麦岭沉积变质磷灰岩选矿技术研究

黄麦岭磷矿属较易选的低品位沉积变质磷灰岩矿,通过扩能改造、回水利用等措施,不仅提高了资源的综合利用率,也为公司每年降低生产成本4 000多万元,创造了可观的经济效益.     

Toxicokinetics of 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) in the European corn borer,Ostrinia nubilalis (Hübner)

2,4-Dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA), the major hydroxamic acid present in corn, and its tritiated derivative, were prepared synthetically for use in the determination of the toxicokinetics of this insect deterrent in the European corn borer (ECB),Ostrinia nubilalis. In growth studies with DIMBOA (0, 0.05, 0.2, and 0.5 mg/g diet), the mean time to pupation and adult emergence were significantly lengthened by an increase in concentration. Pupal and adult weights, for both female and male, decreased with an increase in concentration. Increased larval and pupal mortality occurred at the highest concentration of DIMBOA. DIMBOA, at concentrations of 0.2 and 0.5 mg/g diet, resulted in a decrease in the number of egg masses produced per female, and at 0.5 mg/g diet, in a decrease in the number of eggs per egg mass. Larvae fed from the neonate stage on a diet containing 0.2 mg [³H]- + [¹H]DIMBOA/g diet showed an increase in the content of label from fourth to fifth instar, but levels declined at pupation and emergence. A large amount of the labeled compounds was excreted by the insect in the pupal case. In dose-related studies, both uptake and excretion increased with an increase in concentration of DIMBOA (0.05, 0.2, 0.4 mg/g diet), while a body burden (concentration in the tissues/concentration in the frass) of approximately 0.25 was maintained for all concentrations. At the highest dose of DIMBOA (0.4 mg/g), the ECB increased consumption, possibly to compensate for the toxic effects of the compound. In topical application studies, elimination of the labeled compound in the frass was rapid, reaching 65% by 4 hr and 88% by 48 hr. Accumulation of label in tissues other than hemolymph was low. The results show that the ECB does possess adaptive mechanisms to deal with the effects of this host-derived compound.     

Studies on urethane–allophanate networks based on hydroxyl‐terminated polybutadiene: Modeling of network parameters and correlation to mechanical properties

Hydroxyl‐terminated polybutadiene (HTPB)‐based allophanate–urethane networks were prepared by reacting HTPB with di‐isocyanates, such as toluene–di‐isocyanate (TDI), isophorone–di‐isocyanate (IPDI), and 4,4′‐di(socyanatocyclohexyl)methane (H₁₂MDI) at stoichiometric ratios (r‐values) ranging from 1.0 to 1.5. The networks were characterized for mechanical and swell properties. The network parameters, such as “X,” which is the fraction of urethane groups involved in the allophanate formation, and effective chain length (L_x) were calculated from experimental crosslink density values determined from swell data, using α‐model equations developed by Marsh. Excellent linear correlations were obtained between mechanical properties and the calculated network parameters. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2986–2994, 2006     

机场终端区飞机进近仿真系统的构建

空中交通管制训练仿真系统的主要功能是模拟空中交通,对空管人员进行培训,是空管系统的必备模块,其中如何实现飞行仿真系统,即控制空中目标按照预期的航线飞行并获取精确的飞行航迹是空管训练仿真的基础.在飞行仿真系统中飞行模型的建立是十分重要的,模型的正确与否关系到了空管模拟的逼真度,模型既要满足精度的要求又要满足逼真度的要求,针对这一现实难题使用基于全量运动方程的飞机动力学建模方法,同时配合一种变步长解算方法,最后利用GL Stu-dio软件图形设计器和代码编辑器,结合VC++的混合编程设计方法,实现了对机场终端区飞机进近仿真系统界面的构建.     

深层压裂支撑剂选择探讨

低密度陶粒、覆膜陶粒、覆膜石英砂在浅层压裂应用中表现出了优异的性能,在深层油气藏的压裂改造中是否适用,需进行进一步的研究。从支撑剂的抗破碎能力、导流能力、嵌入程度对比分析了低密度陶粒、覆膜砂、覆膜陶粒的性能,结果表明覆膜陶粒在高压条件下抗破碎能力和导流能力较高,且与岩石的嵌入程度较低,说明覆膜陶粒在深层压裂中具有良好的应用前景。     

基于虚拟人的汽车内饰造型草图设计方法研究

基于当前汽车内饰造型草图设计中存在的问题,引入虚拟人技术生成造型草图设计的辅助模板,建立了基于辅助模板的造型草图设计新方法,并将设计方法进行设计实践,用实际效果验证理论,从而为汽车内饰设计师提供了一种快捷而有效的技术支持方案。     

Relationship between microstructure and mechanical properties of polyether block amide foams

The mechanical behaviors of five polyether block amide foams, obtained by mold-opening foam injection process, were investigated with regard to their microstructures. The materials vary in mass ratios of hard versus soft segments, and/or in process packing time. The resulting microstructures have been characterized in terms of cavity size and shape ratios, by analyzing scanning electron microscope images after careful sample preparation. The foam mechanical responses have been characterized in compression at small and large strain. At small strain, the initial linear part of the stress–strain curve is enhanced firstly by the hard segment mass ratio and secondly by the fineness of the microstructure. Similar results have been obtained at large strain. The foam viscoelasticity at large strain has been characterized by stress relaxation and strain recovery tests, relevant for foam applications. Reduced packing time and pressure have been shown to lead to the presence of undesired large cavities. The morphological defects appear to have a negligible impact on the macroscopic mechanical behavior of the foams at infinitesimal strain, but lead to critical inconsistency at large strain. Furthermore, the mechanical behavior of the tested polyether block amide foams is controlled first by hard versus soft segments ratio, and second by the microstructure fineness.     

不平衡电网下PWM整流器自抗扰模型预测控制

电网电压不平衡时,脉宽调制(PWM)整流器网侧电流产生大量谐波,导致电能质量下降,此外,当负载突变时,系统将长时间处于暂态运行.针对上述问题,这里提出一种基于自抗扰控制器(ADRC)的改进的有限控制集模型预测控制(FCS-MPC)方法.该方法通过对不平衡电网下的网侧功率分析获得新的功率参考值,以此设计评价函数,降低整流器网侧电流畸变率,减小有功功率波动.另外,为提高系统鲁棒性,采用ADRC跟踪电压参考值,提升负载突变时的系统暂态性能,并通过仿真和实验验证所提方法的有效性.     

NH_3 Plasma Surface Treatments of Engineering Fluoropolymers: A Way to Enhance Adhesion of Ni or Cu Thin Films Deposited by Electroless Plating

FLUOROPOLYMERS(FPs)are thermoplasticmaterials which exhibit a number of unique chemicaland physical characteristics that no other man-madeplastic product gets together.For example,FPs showvery good resistance to almost all chemicals,excellentwater vapor barrier properties,high thermal stability,outstanding electrical insulation properties(lowdielectric constant and dissipation factors),extremelylow frictional coefficient giving them high auto-lubrication properties,high resistance to rad…