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61.
Real-time PCR quantification of Vibrio parahaemolyticus in oysters using an alternative matrix 总被引:4,自引:0,他引:4
Kaufman GE Blackstone GM Vickery MC Bej AK Bowers J Bowen MD Meyer RF DePaola A 《Journal of food protection》2004,67(11):2424-2429
This study examined the relationship between levels of total Vibrio parahaemolyticus found in oyster tissues and mantle fluid with the goal of using mantle fluid as a template matrix in a new quantitative real-time PCR assay targeting the thermolabile hemolysin (tlh) gene for the enumeration of total V. parahaemolyticus in oysters. Oysters were collected near Mobile Bay, Ala., in June, July, and September and tested immediately after collection and storage at 26 degrees C for 24 h. Initial experiments using DNA colony hybridization targeting tlh demonstrated that natural V. parahaemolyticus levels in the mantle fluid of individual oysters were strongly correlated (r = 0.85, P < 0.05) with the levels found in their tissues. When known quantities of cultured V. parahaemolyticus cells were added to real-time PCR reactions that contained mantle fluid and oyster tissue matrices separately pooled from multiple oysters, a strong linear correlation was observed between the real-time PCR cycle threshold and the log concentration of cells inoculated into each PCR reaction (mantle fluid: r = 0.98, P < 0.05; and oyster: r = 0.99, P < 0.05). However, the mantle fluid exhibited less inhibition of the PCR amplification than the homogenized oyster tissue. Analysis of natural V. parahaemolyticus populations in mantle fluids using both colony hybridization and real-time PCR demonstrated a significant (P < 0.05) but reduced correlation (r = -0.48) between the two methods. Reductions in the efficiency of the real-time PCR that resulted from low population densities of V. parahaemolyticus and PCR inhibitors present in the mantle fluid of some oysters (with significant oyster-to-oyster variation) contributed to the reduction in correlation between the methods that was observed when testing natural V. parahaemolyticus populations. The V. parahaemolyticus-specific real-time PCR assay used for this study could estimate elevated V. parahaemolyticus levels in oyster mantle fluid within 1 h from sampling time. 相似文献
62.
Ekins J Peters SM Jones YL Swaim H Ha T La Neve F Civera T Blackstone G Vickery MC Marion B Myers MJ Yancy HF 《Journal of food protection》2012,75(6):1107-1112
The U.S. Food and Drug Administration (FDA) has previously validated a real-time PCR-based assay that is currently being used by the FDA and several state laboratories as the official screening method. Due to several shortcomings to the assay, a multiplex real-time PCR assay (MRTA) to detect three ruminant species (bovine, caprine, and ovine) was developed using a lyophilized bead design. The assay contained two primer or probe sets: a "ruminant" set to detect bovine-, caprine-, and ovine-derived materials and a second set to serve as an internal PCR control, formatted using a lyophilized bead design. Performance of the assay was evaluated against stringent acceptance criteria developed by the FDA's Center for Veterinary Medicine's Office of Research. The MRTA for the detection of ruminant DNA passed the stringent acceptance criteria for specificity, sensitivity, and selectivity. The assay met sensitivity and reproducibility requirements by detecting 30 of 30 complete feed samples fortified with meals at 0.1 % (wt/wt) rendered material from each of the three ruminant species. The MRTA demonstrated 100 % selectivity (0.0 % false positives) for negative controls throughout the assessment period. The assay showed ruggedness in both sample selection and reagent preparation. Second and third analyst trials confirmed the quality of the written standard operating procedure with consistency of results. An external laboratory participating in a peer-verification trial demonstrated 100 % specificity in identifying bovine meat and bone meal, while exhibiting a 0.03 % rate of false positives. The assay demonstrated equal levels of sensitivity and reproducibility compared with the FDA's current validated real-time PCR assay. The assay detected three prohibited species in less than 1.5 h of total assay time, a significant improvement over the current real-time assay. These results demonstrated this assay's suitability for routine regulatory use both as a primary screening tool and as a confirmatory test. 相似文献
63.
In contrast to previous literature, we propose that commitment to lean strategy should be preceded by building close relationships with key supply chain partners (suppliers and customers). Two aspects of lean strategy, lean manufacturing and lean design are studied in this paper. We hypothesize that relationship building positively affects both aspects of lean strategy, which in turn positively influences firm performance. To test these relationships, we use data from the top 150 auto suppliers to the ‘Big Three’ original equipment manufacturers (OEMs). The results show positive relationships between (1) relationship building and lean design, (2) relationship building and lean manufacturing, and (3) lean design and firm performance. This suggests that relationship building is more valuable for enhancing the ‘product’ aspects of lean strategy as opposed to the ‘process’ aspects of lean strategy. Process aspects of lean strategy appear to be largely a function of internal efforts. 相似文献
64.
Daniel Skipper Liesbeth Van de Velde Michael Popp Gina Vickery Guido Van Huylenbroeck Wim Verbeke 《Biomass & bioenergy》2009,33(6-7):973-987
Biofuels have been suggested as a sustainable alternative to fossil-based fuels, but when produced with inputs traditionally used as food and feed grain, the production of biofuels has contributed to price increases in the food sector. In the fall of 2006, a survey was administered to compare consumer perceptions regarding the tradeoff between renewable fuels and food in the United States (U.S.) (n = 242) and Belgium (n = 363). Results show that respondents in both countries prefer lower food prices to lower fuel prices (67.6% in the U.S. and 78.9% in Belgium). A logit model was estimated to determine which variables impacted whether a consumer favored policies that lower fuel prices at the cost of higher food prices. While the sample of Belgian respondents appeared to realize that lower fuel prices eventually had to come at the cost of higher food prices, the sample of U.S. respondents felt domestic agriculture could provide some low-cost, environmentally friendly alternatives with little impact on food prices. Accessible public transportation in Belgium acted as an important fuel saving strategy in that country and led respondents to emphasize food price decreases over fuel price decreases. Also, respondents with heightened awareness towards the environment recognized that the expansion of renewable fuels may need to come at the cost of higher food prices. These attitudes were similar in both countries. Finally, in both countries older respondents placed more importance on lower food prices than lower fuel prices. 相似文献
65.
A comprehensive computer program has been developed for carrying out the various tasks associated with radium needle implants. Data input for the program are obtained by digitizing an orthogonal pair of radiographs with an analogue tracing system. Corresponding needles in the two radiographs are automatically located, and the implant may be rotated to any desired position in three dimensional space, at the same time presenting a view of the rotation on a storage oscilloscope. Automatic determination of the mean plane of a planar implant is possible, and the dose-rate distribution may be calculated in any specified plane. A Paterson--Parker exposure rate calculation may be performed with a biological dose and treatment time correction incorporated. The program is written in Fortran and runs on a small interactive computer system. 相似文献
66.
Council James R.; Kirsch Irving; Vickery Anne R.; Carlson Dawn 《Canadian Metallurgical Quarterly》1983,51(3):432
Compared a hypnotic induction procedure based on social learning principles (skill induction) with a traditional eye-fixation/relaxation trance induction, a highly credible placebo induction, and a no-induction base-rate control. Before inductions were administered, 100 undergraduates completed Rotter's Internal–External Locus of Control Scale, the Rotter Trust Scale, and an absorption scale. The trance induction surpassed the skill induction only on the Hypnosis Inventory. Experimenter modeling did not enhance the effectiveness of the skill induction. Skill and trance inductions elicited slightly higher behavioral scores on the Stanford Hypnotic Susceptibility Scale: Form C than did the placebo induction. However, this difference was not obtained on other measures of hypnotic responsivity and depth. Significant correlations were found between expectancy, absorption, and responsiveness on all dependent measures. Multiple regression analyses indicated that the relationship between absorption and responsivity was mediated by expectancy. Results support the hypotheses that hypnotic responses are elicited by the expectancy for their occurrence and that induction procedures are a means of increasing Ss' expectancies for hypnotic responses. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
67.
J. R. Vickery F. B. Whitfield G. L. Ford B. H. Kennett 《Journal of the American Oil Chemists' Society》1984,61(3):573-575
Of 12 Gymnospermae seed and leaf oils, only 2 contained cyclopropene fatty acids. All-cis 5, 11, 14, 17-eicosatetraenoic acid occurred in concentrations up to 11.9% in 6 seed oils, and up to 61% in 2 leaf oils.
The structure of this acid, as its methyl ester, was established by the combination of physical (UV, IR,1H- and13C-NMR and mass spectra) and chemical techniques. Arachidonic acid also occurred in 2 seed oils. 相似文献
68.
M C Vickery M S Vickery C D Amsler J B McClintock 《Microscopy research and technique》2001,55(6):464-473
The ability of echinoderms to regenerate missing body parts has been a subject of interest to scientists for many years. Asexual reproduction (by fission or budding) is a phenomenon that involves regeneration of missing structures. Although asexual reproduction and regeneration have been the focus of many studies in adult echinoderms, there have been comparatively fewer studies examining these phenomena in echinoderm larvae, and most of these have been conducted in the last few years. In this article we review regeneration in larval echinoderms. We also discuss larval asexual reproduction. 相似文献
69.
Near-field scanning optical microscopy and atomic force microscopy are used to probe the sub-micrometre phase structure in palmitic acid monolayers containing the 25 peptide amino terminus of lung surfactant protein B (SP-B1−25 ). Monolayers deposited onto mica substrates at a surface pressure of 15 mN m−1 exhibit a two-phase coexistence across a broad range of SP-B1−25 concentrations. Monolayers containing 5 wt.% SP-B1−25 or less exhibit an expanse of liquid condensed phase in which elliptical liquid expanded (LE) domains with areas of approximately 25 µm2 coexist. By contrast, monolayers containing 20 wt.% SP-B1−25 exhibit an expanse of liquid expanded phase in which circular liquid condensed domains coexist. The phase distribution dependence on SP-B1−25 concentration suggests that the peptide induces disorder in the monolayer. 相似文献
70.
Due to their high corrosion and chemical resistance, fiber reinforced plastic (FRP) materials are increasingly being used in the construction of industrial chimneys. The design of a chimney is governed by wind loads as well as thermal loads resulting from the differences among the ambient, the operating and the curing temperatures. This study involves an investigation for the thermal stresses induced in angle-ply laminated FRP chimneys, using an in-house developed laminated shell element model. The finite element model is verified by performing thermal analysis of a number of plate and shell problems and comparing the results to those available in the literature. An extensive parametric study is then conducted using the shell element model to identify the parameters which significantly affect thermal stresses induced in FRP chimneys.The study indicates that the thermal stresses are only affected by the inclination of the lamina plies, the percentage of fibers content and the through thickness temperature distribution. Analyses also show that localized cracks in the direction perpendicular to the fibers are expected to occur due to the thermal loads. Finally, thermal stress values that can be used in the design of FRP chimneys, when cracking is considered, are presented as function of the through thickness temperature distributions. 相似文献