Molecular and immunologic characterization of group A bovine rotavirus field isolates with P8[11] spike protein

Bovine rotavirus strain B223 is the North American prototype for group A P8[11] serotype/genotype rotaviruses. Rotaviruses with this serotype/genotype are a prevalent cause of neonatal calf diarrhea and have also been isolated from asymptomatic human infants. On the basis of deduced amino acid sequence of the outer capsid viral protein 4 (VP4), strain B223 lacks a cysteine at position 318 that is conserved among all other rotavirus strains. It has been speculated that this may result in the loss of disulfide bond and a change in the structure of the VP4 that may affect the infectivity and antigenicity of the virus. This paper describes partial sequences of the VP4 gene (nucleotides 613 to 1016 coding for amino acid positions 202 to 335) of 16 bovine rotavirus field isolates with P8[11] that were obtained from calves in Nebraska and Indiana. All the isolates lack a cystein at position 203 and had a conserved valine residue at position 318, thus indicating that the prototype strain B223 is representative of group A rotaviruses with P8[11] serotype/genotype.     

高温超导红外探测器的电极工艺探讨

介绍了高温超导红外探测器电极材料的选择和制备。选用先蒸、后蒸金，再合金化的电极工艺。芯片装配成器件后，器件性能稳定，膜层牢固，接触电阻小。     

Ti_3Al PHASE PRECIPITATION DURING VIBRATION FATIGUING FOR A TITANIUM ALLOY

Ｔｉ_３ＡｌＰＨＡＳＥＰＲＥＣＩＰＩＴＡＴＩＯＮＤＵＲＩＮＧＶＩＢＲＡＴＩＯＮＦＡＴＩＧＵＩＮＧＦＯＲＡＴＩＴＡＮＩＵＭＡＬＬＯＹ￥ＴａｏＣｈｕｎｈｕ；ＺｈａｎｇＳｈａｏｑｉｎｇ；ＹａｎＭｉｎｇｇａｏ（ＩｎｓｔｉｔｕｔｅｏｆＡｅｒｏｎａｕｔｉｃａｌＭ?..     

浅成热液金矿成因研究现状与讨论

浅成热液金矿业已成为最重要的金矿类型之一本文探讨了浅成热液金矿成因研究方面若干基本问题:浅成热液金矿的概念和特征、矿床的分类、矿床成因模式。重新厘定了浅成热液金矿的概念.尝试性地按成矿深度和成矿作用方式—斌矿地质环境(容矿岩系)—成矿物理化学条件的分类原则, 将浅成热液金矿分成两大类四种类型:热水沉积岩型、热水火山岩型、浅成热液型和卡林型。前两者为热水沉积型,后两者为热液交代型。在透视现有各种成矿模式的建模依据和存在问题的基础上,指出了今后浅成热液金矿成因研究的发展方向。     

散射式浊度测量仪

浊度是一项评定水质的重要技术指标。如何提高测量浊度的精度是国内外一直在研究的问题之一。文章介绍了作者在散射式浊度测量仪设计过程中，为提高浊度的测量精度和稳定性所做的工作。在测量仪的部件（光学系统，电路系统等）设计中，采取了许多特殊方法，使浊度测量的各项精度指标都得到了较大的提高。     

正电子湮没技术在研究合金形状记忆性能中的应用

本文用正电子湮没技术测试了Cu-Zn-Al形状记忆合金100℃母相时效过程中空位的变化。结果发现,随着时效时间的延长,空位浓度不断降低,空位尺寸不断增大。这一结果很好地解释了记忆合金马氏体逆转变温度As的变化规律,从而证明过饱和空位是Cu-Zn-Al形状记忆合金马氏体稳定化的一个主要原因。     

Fluorimetric determination of monobromobimane and o-phthalaldehyde adducts of gamma-glutamylcysteine and glutathione: application to assay of gamma-glutamylcysteinyl synthetase activity and glutathione concentration in liver

The reversed-phase HPLC separation of fluorescent o-phthalaldehyde (OPA) derivatives has been applied to the assay of hepatic gamma-glutamylcysteine and glutathione (GSH) levels and the enzymes producing these peptides. The method has been compared to the assay using monobromobimane (MB) as the derivatizing agent. The OPA method has the advantage of faster derivatization, the lack of need to adjust the pH, isocratic separation and selectivity for GSH and gamma-glutamylcysteine. The MB method requires pH adjustment following derivatization and gradient elution chromatography. MB is also non-selective, yielding fluorescent derivatives of all biological thiols and more interfering peaks on the chromatogram. MB-based analyses are also approximately sixty times more expensive per sample. MB yields fluorescent degradation products on exposure to light. OPA adducts are stable for up to ten days when stored at -20 degrees C. OPA detection is sensitive to 12.5 pmol in the sample, at a signal-to-noise ratio of 2.5. The two methods correlate well. Hepatic gamma-glutamylcysteine synthetase in the same liver preparation was found to be 4.85 +/- 0.47 nmol min-1 mg-1 protein by the OPA method and 4.42 +/- 0.52 nmol min-1 mg-1 protein by the MB method. GSH concentrations were found to be 90.4 +/- 6.5 nmol/mg protein for the OPA method and 92.5 +/- 3.4 for the MB method.     

Robust controller with disturbance rejection for hydraulic servosystems

A controller is presented that improves the performance and reduces the sensitivity of hydraulic servo systems in the presence of parameter variations, nonlinear effects, and other disturbances. The control system has enhanced closed-loop stability and can recover from steady-state and transient error quickly and completely. It consists of a servo controller, an auxiliary controller, and a robust controller. Simulation and experimental results demonstrate the validity of the controller     

Mechanism of inhibition of tannic acid and related compounds on the growth of intestinal bacteria

Tannic acid, propyl gallate and methyl gallate, but not gallic acid, were found to be inhibitory to the growth of intestinal bacteria Bacteroides fragilis ATCC 25285, Clostridium clostridiiforme ATCC 25537, C. perfringens ATCC 13124, C. paraputrificum ATCC 25780, Escherichia coli ATCC 25922, Enterobacter cloacae ATCC 13047, Salmonella typhimurium TA98 and S. typhimurium YG1041 at 100-1000 microg/ml in culture broth. Neither Bifidobacterium infantis ATCC 15697 nor Lactobacillus acidophilus ATCC 4356 was inhibited by any of the above compounds up to 500 microg/ml. Tannic acid has a much greater relative binding efficiency to iron than propyl gallate, methyl gallate or gallic acid. The inhibitory effect of tannic acid to the growth of intestinal bacteria may be due to the strong iron binding capacity of tannic acid; whereas the effect of propyl gallate and methyl gallate probably occurs by a different mechanism. The growth of E. coli was restored by the addition of iron to the medium after the precipitate caused by tannic acid was removed. Neither B. infantis nor L. acidophilus require iron for growth. This probably contributes to their resistance to tannic acid. Because tannins are abundant in the human diet, tannins may affect the growth of some intestinal bacteria and thus may have an impact on human health.