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121.
The major factor limiting resolution of metal-shadowed surfaces for electron and scanning tunnelling microscopy is the granularity of the metal film. This granularity had been believed to result from a recrystallization of the evaporated film, and hence could be limited by use of higher melting point materials for replication, or inhibited by adding carbon or other impurities to the film. However, evaporated and sputtered films of amorphous metal alloys that do not crystallize also show a granularity that decreases with increasing alloy melting point. A simple thermodynamic analysis shows that the granularity results from a dewetting of the typically low surface energy sample by the high surface energy metal film, similar to the beading up of drops of spilled mercury. The metal granularity and the resulting resolution of the metal-coated surface is proportional to the mobility of the metal on the surface after evaporation, which is related to the difference in temperature between the melting point of the metal and the sample surface temperature. 相似文献
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Yiping He Xiaomin Yao Nereus W. Gunther IV Yanping Xie Shu-I Tu Xianming Shi 《Food Analytical Methods》2010,3(4):321-329
A multiplex real-time PCR (qPCR) assay was developed for simultaneous detection and differentiation of the three most important
Campylobacter species in chickens. Three novel sets of PCR primers and TaqMan probes were designed to amplify the unique DNA sequences
within the hipO, cdtA, and pepT genes which are specific to Campylobacter jejuni, Campylobacter coli, and Campylobacter lari, respectively. To avoid competition in the multiple target amplifications, the concentrations of primers and probes were
optimized. By using the optimized qPCR conditions together with a minor-groove binding probe of pepT, amplification efficiency greater than 92% and detection sensitivity of 38 genome copies/reaction have been achieved for
all three targets. The assay was highly specific for C. jejuni, C. coli, and C. lari with testing of 33 Campylobacter strains and 20 non-Campylobacter strains. In chicken samples spiked with known quantities of Campylobacter cells, the assay was able to detect 1 CFU/g after a 24-h enrichment. Application of the assay in food was further evaluated
using 21 fresh chicken samples obtained from local supermarkets. The results revealed that, after a 24-h or 48-h enrichment,
14 samples (66.7%) were positive for C. jejuni, five samples (23.8%) were positive for C. coli, and none of the samples was contaminated by C. lari. Taken together, the multiplex qPCR assay combined with an enrichment step is a sensitive, species-specific, and non-labor-intensive
method suitable for rapid detection of C. jejuni, C. coli, and C. lari in chicken samples. 相似文献
124.
Jay Edneil C. Olivar Joanner Paulus Erik P. Alaba Jose Francisco M. Atienza Jerick Jeffrey S. Tan Maximo T. Umali IV Grecebio Jonathan D. Alejandro 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2016,33(5):741-748
The majority of the population in the Philippines relies on herbal products as their primary source for their healthcare needs. After the recognition of Vitex negundo L. (lagundi) as an important and effective alternative medicine for cough, sore throat, asthma and fever by the Philippine Department of Health (DOH), there was an increase in the production of lagundi-based herbal products in the form of teas, capsules and syrups. The efficiency of these products is greatly reliant on the use of authentic plant material, and to this day no standard protocol has been established to authenticate plant materials. DNA barcoding offers a quick and reliable species authentication tool, but its application to plant material has been less successful due to (1) lack of a standard DNA barcoding loci in plants and (2) poor DNA yield from powderised plant products. This study reports the successful application of DNA barcoding in the authentication of five V. negundo herbal products sold in the Philippines. Also, the first standard reference material (SRM) herbal library for the recognition of authentic V. negundo samples was established using 42 gene accessions of ITS, psbA-trnH and matK barcoding loci. Authentication of the herbal products utilised the SRM following the BLASTn and maximum-likelihood (ML) tree construction criterion. Barcode sequences were retrieved for ITS and psbA-trnH of all products tested and the results of the study revealed that only one out of five herbal products satisfied both BLASTn and ML criterion and was considered to contain authentic V. negundo. The results prompt the urgent need to utilise DNA barcoding in authenticating herbal products available in the Philippine market. Authentication of these products will secure consumer health by preventing the negative effects of adulteration, substitution and contamination. 相似文献
125.
The interactive effect of fungicide residues and yeast assimilable nitrogen on fermentation kinetics and hydrogen sulfide production during cider fermentation 下载免费PDF全文
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Laura Vázquez‐Araújo Edgar Chambers IV Panat Cherdchu 《Journal of food science》2012,77(10):S384-S389
Abstract: Because sorghum grain has important characteristics (for example, great antioxidant profile) for introduction into the regular human diet, producers and industry aim to develop successful products using sorghum as the base. The 1st step in developing products attractive for consumers is understanding consumer needs and expectations. Conjoint analysis determines attributes which may be important or unimportant for one product. In this study, focus groups and conjoint analysis were used to establish which attributes are helpful for promoting purchase intent of sorghum grain products. Once those characteristics were chosen, a national survey was conducted to confirm the selection. During the focus groups, the heath aspects of grain products seemed to be the most appealing for consumers, whereas conjoint analysis showed that sensory attributes were the principal drivers for purchase intent. Practical Application: The data presented in this study are essential for industry as a starting point for developing sorghum grain based food products. It is necessary to address consumers’ demands to ensure new products’ success in the market, and the present study clearly shows this consumers’ input. 相似文献
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NN Kudriavtseva IV Bakshtanovskaia DF Avgustinovich 《Canadian Metallurgical Quarterly》1997,47(1):86-97
The influence of repeated experience of aggression in daily intermale confrontations on individual and social behaviour was studied in male mice of C57BL/6J (C57) and CBA/Lac (CBA) strains. Repeated experience of aggression led to a decrease of emotionality in males of highly emotional CBA strain and increase in exploratory activity in the open field and exploratory activity tests, decrease of immobility time in Porsolt's test and pain sensitivity estimated by the "hot plate" test. Low emotional C57 males did not change their individual behaviour in different situations under the influence of repeated experience of aggression. However, aggressive C57 mice demonstrated anxiety-like behaviour estimated in the plus-maze test. In the partition test aggressive mice of both strains showed an increase in communicative level (as a reaction to a familiar male) in comparison with their behaviour before aggressive confrontations. Behavioural reaction to a receptive female under unfamiliar conditions decreased which testified to a decrease in sexual motivation. It is concluded that formation of the aggressive type of social behaviour is accompanied by changes in the individual and social behaviour of male mice. Characteristics of these changes are genetically determined and depend on the duration of confrontations. 相似文献
130.
IM Rabinovich IV Bezrukova VV Khazanova EA Zemskaia NA Dmitrieva 《Canadian Metallurgical Quarterly》1997,76(4):12-17
Fifty-two patients with lichen planus were examined over the course of disease using clinical, microbiological, and histological methods. Treatment protocols aimed at normalization of microbiocenosis have been developed, based on the detected microbiological and histological changes. 相似文献