污水处理厂恶臭含硫化合物的研究

分析了污水处理厂各个不同工艺段气、液两相中恶臭有机含硫化合物的分布情况,同时运用气相色谱-质谱联用仪及吹扫-捕集系统对甲硫醇、甲硫醚、羰基硫、二硫化碳和二甲二硫等五种化合物进行了定性准确的和定量分析,并对其产生机制及来源进行了较为详实的解析.其中挥发性气体样品的采集通过动态箱收集,溶解在水体中的目标化合物运用高纯氮气吹脱收集.研究结果表明,在水相和气相中的恶臭化合物的分布在不同的处理单元呈现不同的恶臭浓度,但经过污水处理厂各工艺的深度处理后, 溶解在水体当中的恶臭含硫化合物及挥发到大气中的化合物均有明显下降,去除率均达到90%以上.     

烧成及热处理工艺对钛酸锶铅基热敏材料性能及显微结构的影响

研究了烧成及热处理工艺对钛酸锶铅基热敏材料的阻温特性及显微结构的影响。通过扫描电镜（ＳＥＭ）和能量分散仪（ＥＤＡＸ）分析了材料的显微结构及不同形貌晶粒的成份。通过对组成、烧成及热处理工艺的控制，可得到具有Ｖ型ＰＴＣＲ特性的热敏材料。     

ERCP and CT findings of ectopic drainage of the common bile duct into the duodenal bulb

OBJECTIVE: The purpose of this study was to evaluate ERCP and CT findings of ectopic drainage of the common bile duct into the duodenal bulb. CONCLUSION: Although rare, the diagnosis of ectopic drainage of the common bile duct into the duodenal bulb is important to prevent inadvertent damage during biliary tract or gastric surgery and to clarify the cause of chronic peptic ulcers.     

Phacoemulsification with a bevel-down phaco tip: phaco-drill

We present a technique for in situ lens nucleus emulsification using low phaco power and high vacuum, a continuous curvilinear capsulorhexis, and hydrodelineation. Emulsification is done with the phaco tip slanted down 30 or 45 degrees. Cutting and aspiration do not cause an undesirable energy loss. This technique can be combined with the nuclear chopping or divide and conquer methods because of its ability to drill and hold the nucleus. Posterior capsular rupture is prevented because the separated epinucleus acts as a barrier between the nucleus and the cortex. The low power used minimizes the energy transfer to the corneal endothelium. This technique is particularly useful in eyes with brunescent cataract.     

碾压混凝土坝施工进度与质量控制的新措施

碾压混凝土重力坝和拱坝由于连续施工的坝体混凝土体积大，施工期间需要采取较为严格的温度控制措施，而所采取的温控措施是否有效，目前尚没有一个能够用于实际施工过程的快速有效的评估方法和方式，不能根据已施工坝体内的实际情况来控制施工进度和质量。利用分布式光纤温度测量系统来快速地获得坝体混凝土内部的大量温度信息，进而实际标定温度仿真程序并通过标定过程模拟拟施工的连续碾压层，以检验其温控措施的有效性。通过坝体内部的温度、温度变化速率和梯度来达到实时控制坝体碾压上升速度、坝面和仓面养护、以及冷缝灌浆处理等目的。     

Effect of postischemic reperfusion on microcirculation and lipid metabolism of skeletal muscle

To study the effect of ischemia reperfusion injury on microvascular reactivity and tissue metabolism in skeletal muscle, a Sprague-Dawley rat cremaster muscle was prepared as a tourniquet ischemia model and subjected to 2 hr ischemia followed by 1 hr reperfusion to simulate the timing of ischemia during microvascular surgery. The dose-response curve of arteriolar reactivity to norepinephrine, lipid peroxidation, and ultrastructure of capillaries was determined in both the control and postischemic reperfusion stages. Judging from the results, we summarize our observations as follows: (1) Postischemic reperfusion significantly increased arteriolar reactivity to norepinephrine, in which the EC50 for vasoconstriction decreased in all three orders of arterioles. These results suggest that reperfusion could have impaired the vasodilation control mechanism, possibly being endothelium dependent. (2) Lipid peroxidation increased sixfold in the reperfusion group, suggesting that oxygen free radicals have produced significant tissue damage under the created conditions. (3) Significant endothelial damage in the capillaries shown by electron microscope observation supports these studies, indicating that ischemia/reperfusion in clinically transplanted skeletal muscles could cause significant damage to the tissue microcirculation both physiologically and metabolically.     

Role of conserved Asn-Tyr-Asp-Tyr sequence in bacterial copper/2,4, 5-trihydroxyphenylalanyl quinone-containing histamine oxidase

Copper amine oxidase contains a covalently bound quinonoid cofactor, 2,4,5-trihydroxyphenylalanyl quinone (TPQ), which is synthesized by post-translational modification of a specific tyrosyl residue occurring in the highly conserved sequence, Asn-Tyr-(Asp/Glu)-Tyr. To elucidate the role(s) of the conserved sequence in the biogenesis of TPQ, each of the corresponding residues at positions 401-404 in the recombinant histamine oxidase from Arthrobacter globiformis has been replaced with other amino acids by site-directed mutagenesis. When Asn-401 was changed to Asp or Gln, the rate of TPQ formation by copper-dependent self-processing was 10(3)- to 10(4)-fold slower than in the wild-type enzyme. When Tyr-402 was replaced by Phe, TPQ was not formed at all, showing that Tyr-402 is essential as the precursor to TPQ. In contrast, Asp-403 could be replaced by Glu without changes in the rate of TPQ formation, whereas its replacement by Asn led to a marked decrease. Furthermore, when Tyr-404 was changed to Phe, TPQ was formed swiftly on incubation with copper ions, but the TPQ enzyme exhibited very low activity with altered substrate specificity. These results collectively indicate that a very rigorous structural motif is required for efficient formation of TPQ and for the catalytic activity in the active site of copper amine oxidases.