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991.
Rosa Raybaudi-Massilia Alexandra Zambrano-Durán Jonathan Mosqueda-Melgar María Isabel Calderón-Gabaldón 《Journal für Verbraucherschutz und Lebensmittelsicherheit》2012,7(4):273-282
In this research, several plant compounds were in vitro evaluated against Salmonella enterica ser. Saintpaul and Escherichia coli O157:H7 through disc’s method. Among them Panax ginseng (PG) showed the highest antimicrobial activity in comparison to other natural antimicrobials. Combinations of PG (2?% v/v) with malic acid (MA) (0.5?% v/v) and/or potassium sorbate (PS) (0.05?% v/v) were made for evaluating their effects on S. Saintpaul and E. coli O157:H7 populations in sterile and fresh mango and orange juices stored at 5?°C. The best combination of antimicrobial compounds on native flora (during 21?days) as well as sensory attributes (0?day) of fresh juices were evaluated. The antimicrobial compounds added into mango and orange juices were more effective against S. Saintpaul than against E. coli O157:H7. The combination of PG (2?% v/v), MA (0.5?% v/v) and PS (0.05?% v/v) showed the highest antimicrobial effectiveness against both pathogenic microorganisms in both juices, in addition to a higher microbiological inhibition during storage (21?days). Sensory attributes such as aroma, color and taste were enhanced, but acidity was notably affected in both juices. In conclusion, the combination of PG, MA and PS could be an effective method in the food industry for ensuring the microbial safety and quality in mango and orange juices. 相似文献
992.
Angela Pineda Jonathan CarrascoCarlos Peña-Farfal Karem Henríquez-AedoMario Aranda 《Food Control》2012,23(1):251-257
Biogenic amines are organic nitrogenous compounds produced in wines mainly during malolactic fermentation. Its presence is a health risk for sensitive individuals and it could negatively affect the wine quality. The objective of this work was to determine the biogenic amines content in Chilean young varietal wines. For that, a liquid chromatographic method with pre-column derivatization was optimized and validated to achieve a reliable quantification of the most important biogenic amines in wines, i.e. histamine, tyramine, spermine, spermidine, putrescine, cadaverine and phenylethylamine. Using a face-centered central composite design derivatization and chromatographic conditions were optimized. Derivatization with dansyl chloride showed an optimum yield for all biogenic amines at 60 °C during 60 min. These derivatives were optimally separated with a C18 YMC-Pack ODS-A column set a 40 °C using a mobile phase composed of acetonitrile and water under gradient conditions. An effective separation and quantification of the biogenic amines was achieved in 40 min using ultraviolet detection at 254 nm. Validation was established according to ICH guidelines, calibrations in matrix fitted a linear regression model with R2 > 0.997. Repeatability (n = 6) and intermediate precision (n = 3) in matrix showed RSD values <2.34% and <3.16%, respectively. This method was applied to determine for the first time the biogenic amines content in Chilean wines. Twenty-seven samples of young varietal wines, i.e. Cabernet Sauvignon (n = 9), Merlot (n = 8) and Carménère (n = 10) were analyzed finding a biogenic amines content from 18.12 to 39.84 mg L-1, where putrescine showed the highest concentration in all grape varieties. No significant difference was found between grapes varieties regarding total biogenic amines content (P = 0.7842, df = 26). Along with putrescine, histamine and tyramine were the most abundant biogenic amines but similar levels were also observed with spermidine. 相似文献
993.
Jonathan Katz 《Journal of Cryptology》2012,25(1):41-56
We show that if a language L has a 4-round, black-box, computational zero-knowledge proof system with negligible soundness error, then [`(L)] ? MAbar{L}in mathsf{MA}. Assuming the polynomial hierarchy does not collapse, this means in particular that NP-complete languages do not have 4-round zero-knowledge proofs with black-box simulation. 相似文献
994.
995.
Computer rendering and visual detection of orange peel 总被引:1,自引:0,他引:1
The computer graphic simulation of a common spray painting artifact, called orange peel, is discussed. Orange peel distorts surface reflections and is commonplace in product design applications. The orange peel measurements from a standard industrial instrument are used to construct a height field, and this surface is rendered using traditional normal mapping techniques. Comparisons are made between real panels with orange peel and simulations of those panels. A simple visual model for detecting the presence of orange peel is also presented and evaluated. User testing of the model confirms that orange peel is more visible on dark paint colors than on light paint colors. The latter outcome suggests that to minimize application time, but still keep orange peel below visual threshold, paint application systems should be designed to take paint color into account. 相似文献
996.
997.
998.
Valuing vegetation in an urban watershed 总被引:1,自引:0,他引:1
Jonathan Kadish 《Landscape and urban planning》2012,104(1):59-65
This study uses the hedonic price method to examine if land cover types-trees, shrubs, water and impervious surface areas-affect the sale price of single-family residential properties in Multnomah County, Oregon. We combine detailed structural and location information for 36,753 single-family residential property sales with the percentage of land cover on each property and within three buffers surrounding each property. Trees contribute positively to a property's sale price, but the estimated increase may be less than the costs of planting and caring for trees. Benefits received by nearby property owners may justify actions by government agencies to expand canopy coverage. 相似文献
999.
Dr. Ying‐Ying Huang Dr. Thiagarajan Balasubramanian Dr. Eunkyung Yang Dr. Dianzhong Luo Dr. James R. Diers Prof. David F. Bocian Prof. Jonathan S. Lindsey Prof. Dewey Holten Dr. Michael R. Hamblin 《ChemMedChem》2012,7(12):2155-2167
A series of four stable synthetic bacteriochlorins was tested in vitro in HeLa cells for their potential in photodynamic therapy (PDT). The parent bacteriochlorin (BC), dicyano derivative (NC)2BC and corresponding zinc chelate (NC)2BC–Zn and palladium chelate (NC)2BC–Pd were studied. Direct dilution of a solution of bacteriochlorin in an organic solvent (N,N‐dimethylacetamide) into serum‐containing medium was compared with the dilution of bacteriochlorin in Cremophor EL (CrEL; polyoxyethylene glycerol triricinoleate) micelles into the same medium. CrEL generally reduced aggregation (as indicated by absorption and fluorescence) and increased activity up to tenfold (depending on bacteriochlorin), although it decreased cellular uptake. The order of PDT activity against HeLa human cancer cells after 24 h incubation and illumination with 10 J cm?2 of near‐infrared (NIR) light is (NC)2BC–Pd (LD50=25 nM ) > (NC)2BC > (NC)2BC–Zn ≈ BC. Subcellular localization was determined to be in the endoplasmic reticulum, mitochondria and lysosomes, depending on the bacteriochlorin. (NC)2BC–Pd showed PDT‐mediated damage to mitochondria and lysosomes, and the greatest production of hydroxyl radicals as determined using a hydroxyphenylfluorescein probe. The incorporation of cyano substituents provides an excellent motif for the enhancement of the photoactivity and photostability of bacteriochlorins as PDT photosensitizers. 相似文献
1000.