Patterns of CCR5, CXCR4, and CCR3 usage by envelope glycoproteins from human immunodeficiency virus type 1 primary isolates

Coreceptor usage by Envs from diverse primary human immunodeficiency virus type 1 isolates was analyzed by a vaccinia virus-based expression and assay system. Usage of recombinant CCR5 and CXCR4 correlated closely with fusogenicity toward macrophages and T-cell lines expressing endogenous coreceptors. Surprisingly, recombinant CCR3 was utilized by most primary and T-cell-line-adapted Envs. Endogenous CXCR4 in macrophages was functional as a coreceptor.     

Measurement of endwall heat transfer and pressure drop in a pin-fin wedge duct

This paper discusses the measurements of endwall heat transfer and pressure drop in a wedge-shaped duct inserted with an array of circular pin fins. The endwall surface is coated with a thin layer of thermochromic liquid crystals and a transient test is run to obtain detailed heat transfer distributions. Parametric studies include Reynolds number (10,000?Re?50,000), outlet flow orientation (straight and lateral) and pin configuration (staggered and in-line). The wedge duct has a convergent angle of 12.7°. The pin spacing-to-diameter ratios along the longitude and transverse directions are fixed at s_x/d=s_y/d=2.5. Pin-less wedge duct results are also obtained for comparison. Results indicated that the straight wedge duct with a staggered pin array is most recommended because of its significant endwall heat transfer and moderate pressure-drop penalty; while the turned wedge duct with a staggered pin array is least recommended since it yields the highest pressure drops and raises severe hot spots. A similarity of the pin Reynolds-number dependence of row-averaged Nusselt number is developed in the present wedge duct of accelerating flow.     

Inactivation and modification of phosphoenolpyruvate carboxykinase differentially labeled with bromopyruvate

Phosphoenolpyruvate carboxylkinase (GTP:oxaloacetate carboxy-lyase (transphosphorylating), EC 4.1.1.32) is inactivated by bromopyruvate with specific substrate protection against the inactivation. Despite the fact that the enzyme also is known to possess oxalacetate decarboxylase activity, the modification does not appear to be directed toward a pyruvate or enolpyruvate binding site, as evident from the kinetics of the inactivation and from protection studies. Thus, the reactivity of bromopyruvate is different than toward several other enzymes where pyruvate is a substrate or product. Acetopyruvate and oxalate inhibit carboxykinase activity, but neither of these compounds, nor pyruvate, protects against the inactivation. Using differentially labeled enzyme, it was shown that modification of one sulfhydryl is sufficient to cause loss of both catalytic activities. Protection by inosine nucleotides was found to be similar in each instance. It would appear that a common sulfhydryl is critical to both carboxykinase and oxalacetate decarboxylase activities, and that each utilizes the same nucleotide binding site, despite the known different roles of the nucleotide in each reaction.     

公安消防特勤部队参加四川汶川大地震应急救援的实践与启示

对汶川大地震中公安消防特勤部队应急救援实践进行了总结,并对今后的应急救援服务提出了改进建议。     

Tests of cold-formed high strength stainless steel compression members

The paper describes a test program on cold-formed high strength stainless steel compression members. The duplex stainless steel having the yield stress and tensile strength up to 750 and 850 MPa, respectively, was investigated. The material properties of the test specimens were obtained from tensile coupon and stub column tests. The test specimens were cold-rolled into square and rectangular hollow sections. The specimens were compressed between fixed ends at different column lengths. The initial overall geometric imperfections of the column specimens were measured. The strength and behaviour of cold-formed high strength stainless steel columns were investigated. The test strengths were compared with the design strengths predicted using the American, Australian/New Zealand and European specifications for cold-formed stainless steel structures. Generally, it is shown that the design strengths predicted by the three specifications are conservative for the cold-formed high strength stainless steel columns. In addition, reliability analysis was performed to evaluate the current design rules.