Post-processing application of chemical solutions for control of Listeria monocytogenes, cultured under different conditions, on commercial smoked sausage formulated with and without potassium lactate-sodium diacetate

This study evaluated post-processing chemical solutions for their antilisterial effects on commercial smoked sausage formulated with or without 1.5% potassium lactate plus 0.05% sodium diacetate, and contaminated (approximately 3-4 log cfu/cm(2)) with 10-strain composite Listeria monocytogenes inocula prepared under various conditions. Inoculated samples were left untreated, or were immersed (2 min, 25 +/- 2 degrees C) in solutions of acetic acid (2.5%), lactic acid (2.5%), potassium benzoate (5%) or Nisaplin (0.5%, equivalent to 5000 IU/ml of nisin) alone, and in sequence (Nisaplin followed by acetic acid, lactic acid or potassium benzoate), before vacuum packaging and storage at 10 degrees C (48 days). Acetic acid, lactic acid or potassium benzoate applied alone reduced initial L. monocytogenes populations by 0.4-1.5 log cfu/cm(2), while treatments including Nisaplin caused reductions of 2.1-3.3 log cfu/cm(2). L. monocytogenes on untreated sausage formulated with antimicrobials had a lag phase duration of 10.2 days and maximum specific growth rate (mu(max)) of 0.089 per day, compared to no lag phase and mu(max) of 0.300 per day for L. monocytogenes on untreated product that did not contain antimicrobials in the formulation. The immersion treatments inhibited growth of the pathogen for 4.9-14.8 days on sausage formulated without potassium lactate-sodium diacetate; however, in all cases significant (P < 0.05) growth occurred by the end of storage. The antilisterial activity of chemical solutions was greatly enhanced when applied to product formulated with antimicrobials; growth was completely inhibited on sausage treated with acetic or lactic acid alone, and in sequence with Nisaplin. In general, habituation (15 degrees C, 7 days) of L. monocytogenes cells, planktonically or as attached cells to stainless-steel coupons in sausage homogenate prior to contamination of product, resulted in shorter lag phase durations compared with cells cultivated planktonically in a broth medium. Furthermore, when present, high levels of spoilage flora were found to suppress growth of the pathogen. Findings of this study could be useful to US meat processors in their efforts to select required regulatory alternatives for control of post-processing contamination in meat products.     

一种与众不同的染色方法

随着纤维、染料、助剂、染色工艺以及印染机械的更新，纺织染色世界不断发生变化，获得了特殊的颜色效果。其中的一些变化出现在特殊纺织品，如地毯上。而另外的变化出现在纺织原料的生产中，如机织物、针织物、服装、袜类等。     

流态化及缓苏干燥技术对泰国香稻的香味和磨粉品质的影响

将高温（〉100。C）流态化干燥和缓苏相结合干燥泰国香稻（KhaoDawkMali105,籼稻）,使其湿含量降至13-14％（湿基）,以便于安全贮存。研究了干燥与贮存过程对籼米香味和磨粉品质的影响。泰国香稻需要经过两个干燥阶段。第一阶段是在高温流化床中干燥,缓苏30分钟,然后返回高温流化床干燥或阴干,直至湿含量降低到安全贮存水平。实验结果表明,干燥温度对香稻的整精米率（HRY）、白度指数（wI）和2AP含量均有影响。多数干燥温度下整精米率的水平都比较低,但150℃除外,此情况下整精米率（psO．05）显著提高。然而,当一次流态化干燥和缓苏之后,以阴干代替二次流态化干燥,香稻的整精米率显著增加,尤其是在135℃和50℃时（p≤O．05）。在贮存期间,白度指数和2AP舍量显著降低（ps0．05）,而整精米率保持不变。对比环境温度（28．30℃）和15℃贮存温度,结果表明保持香米2AP舍量和白度指数的适宜保存温度是15℃。然而贮存条件对整精米率影响不大（p〉0．05）。本研究将有益于泰国香米行业的发展,为泰国香米的干燥起到指导性作用。     

Enhanced antibacterial effect of silver nanoparticles obtained by electrochemical synthesis in poly(amide-hydroxyurethane) media

In the present study, we report enhanced antimicrobial properties of 29 and 23 nm silver nanoparticles (Ag NPs) obtained by electrochemical synthesis in poly(amide-hydroxyurethane) media. Antibacterial activity assessed by disk diffusion method indicates that silver nanoparticles produced inhibition zones for both Escherichia coli and Staphylococcus aureus depending on silver concentration. The bacterial growth curve performed in the presence of silver nanoparticles showed a stronger antibacterial effect at lower concentrations than those described in the earlier reports. The effect was both dose and size dependent and was more pronounced against Gram negative bacteria than Gram positive one. The smallest Ag NPs used had a bactericidal effect resulting in killing E. coli cells. Scanning electron microscopy analysis indicated major damage and morphology changes of the silver nanoparticles treated bacterial cells. The major mechanism responsible for the antibacterial effect probably consists in clusters formation and nanoparticles anchorage to the bacterial cell surface.     

矿石贫化对地下矿山生产成本的影响

加拿大地下金属矿山的全部矿石产量中大约有51％是用空场采矿法开采的。这种采矿法要求在以可接受的最小贫化程度采出矿石之前，采场是空敞的。1988年对地下矿山的一项调查表明：这些矿山关闭的一个重要因素是贫化失控。据报道，有40％的空场采矿作业的矿石贫化超过20％，这样高的贫化程度对矿山的经济生存有深刻的影响，尤其当一个矿山企业的收益率一般要在10％～20％之间时，贫化问题更为敏感。本文对贫化的定义、现行的减少贫化的矿房设计方法、以及现时可用的贫化测定技术做了报道。     

Potent inhibitors of the human UDP-glucuronosyltransferase 2B7 derived from the sesquiterpenoid alcohol longifolol

The tricyclic sesquiterpenol (+)-longifolol served as a lead structure for the design of inhibitors of the human UDP-glucuronosyltransferase (UGT) 2B7. Twenty-four homochiral and epimeric longifolol derivatives were synthesized and screened for their ability to inhibit the enzyme. The absolute configuration at the stereogenic center C1' was determined by X-ray crystallography and 2D NMR spectroscopy (gHSQC, gNOESY). The phenyl-substituted secondary alcohol 16 b (beta-phenyllongifolol) displayed the highest affinity toward UGT2B7, and its inhibitory dissociation constant was 0.91 nM. The mode of inhibition was rapidly reversible and competitive. The inhibitor was not glucuronidated by UGT2B7 or other hepatic UGTs, presumably as a result of the high steric demand exerted by the phenyl group. Inhibition assays employing 14 other UGT isoforms suggested that inhibitor 16 b was highly selective for UGT2B7.     

Emerging technologies for identification of disinfection byproducts: GC/FT-ICR MS characterization of solvent artifacts

Water samples from a local water treatment plant were analyzed, using gas chromatography Fourier transform ion cyclotron resonance mass spectrometry (GC/FT-ICR MS), to identify potential disinfection byproducts (DBPs). Both liquid-liquid extraction (LLE) and solid-phase microextraction (SPME) techniques were used for sample preparation prior to GC/MS analyses. Based on the averaged mass measurement accuracy (MMA) of better than five parts-per-million (<5 ppm), multiple solvent artifacts were identified. It is shown that solventless SPME can be utilized to reduce potential interferences from solvent stabilizers. Six DBPs were detected and their molecular compositions were assigned at a high level of confidence. At the ppb concentration ranges and in the broadband mass spectral detection mode, internally calibrated mass spectra provided concurrent high resolution (resolving power M/deltaM50% > 30,000 at m/z values -110) and MMA of better than one part-per-million (MMA < 1 ppm). The use of thermochemical data, such as proton affinities, as a complementary tool to enhance analytical resolution is also demonstrated.     

用地震勘探法探测印度几座大坝下游的冲刷深度

在斯利塞拉姆大坝的施工过程中，我们在靠近坝址处观测到深度冲刷。在1977年和1987年间采取了不同保护措施，但1987年探测显示基准线下游距离206m处有一个冲刷坑。1995年该冲刷坑向上游发展约60m。因此人们担心冲刷坑可能影响下游保护工程的稳定。为了更清楚地确定这一问题，对覆盖67000m^2面积的24个横断面进行地震反射法勘探以及沿8个剖面用拍摄进行地震反射法勘探。使用数组垂直水下测听器在下游水池的最深部位的剖面进行折射测试。该勘测表明存在一个波速为2000至2600m/s不等的覆盖层。这个覆盖层由波速为4000至5500m/s不等的石英岩支撑，河床的岩石深度在2．0和14．0m之间。地震反射结果决定了河床区域外形和泥沙的厚度。河床高程从137．2到155．4m不等，两岸边坡极为陡峭。在接近厂房距离大坝基准线50m处，岩石高程为152.4m，而在距离130m处岩石高程为134.1m。靠近左岸的岩石高程比1968／1969年钻孔的岩石高程深，这表明已经发生冲刷，并发现冲刷深度2到4m不等。     

全球最大宝石收藏馆 希望钻石之家

1958年，11月10日，一个普通的棕色信封通过美国邮政公司被邮寄到位于华盛顿的Smithsonian Insititution，信封上标记着：邮寄人HarryWinston，博物馆的标本接收处专员像往常一样，签收并送往储藏标本室，之后博物馆的管理人员将标本拆封，仔细的记录好，并给此标本命名了编号：标本#217868，这一切看上去是那么的平常。但就是在这一天，在这个信封里，装载着世界上最著名的蓝色钻石——价值3000万美金的希望钻石。