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排序方式: 共有556条查询结果,搜索用时 15 毫秒
31.
Pappier U Fernández Pinto V Larumbe G Vaamonde G 《International journal of food microbiology》2008,125(2):153-157
Incidence of fungal contamination of quinoa seeds from three locations (Salar de Uyuni, Bolivia; Salta and Tucumán provinces, Argentina) was analyzed in samples with and without treatment to remove saponins (wet method). In processed samples, the percentage of infection was reduced. Distribution of the different fungal genera was not homogeneous in the three locations (p<0.05), although Penicillium and Aspergillus were the most prevalent contaminants, regardless the geographic origin of the samples. Other genera, such as Eurotium, Fusarium, Phoma, Ulocladium, Mucor and Rhizopus were less frequently isolated. Absidia, Alternaria, Cladosporium, Dreschlera, Epicoccum and Monascus were sporadically encountered. Significant differences (p<0.05) in the distribution of fungal genera in samples with and without saponins from each location were observed. In all cases, processing caused a decrease of Aspergillus incidence, while increased the proportion of Penicillium, Eurotium, Mucor and Rhizopus indicating that these genera were part of the internal mycota. A. flavus and A. niger were the dominating species of genus Aspergillus. A similar pattern of prevalent Penicillium species was observed in samples with and without saponins, since P. aurantiogriseum, P.chrysogenum, P. citrinum and P. crustosum were always present in high number, although their relative density was variable according to the geographic origin of samples. Mycotoxin-producing ability of most representative species was also determined. Toxigenic strains of A. flavus (aflatoxins and cyclopiazonic acid), A. parasiticus (aflatoxins), P. citrinum (citrinin) and P. griseofulvum (cyclopiazonic acid) were found. None of the A. niger isolates was ochratoxin A producer. The above mentioned mycotoxins were not detected in the samples analyzed. 相似文献
32.
Alicja Tymczewska Bliss Ursula Furtado Jacek Nowaczyk Katarzyna Hrynkiewicz Aleksandra Szydowska-Czerniak 《International journal of molecular sciences》2022,23(5)
This study aimed to develop and characterize gelatin/polyvinyl alcohol (G/PVA) films loaded with black cumin cake extract (BCCE) and zinc oxide nanoparticles (ZnONPs). The BCCE was also applied for the green synthesis of ZnONPs with an average size of less than 100 nm. The active films were produced by a solvent-casting technique, and their physicochemical and antibacterial properties were investigated. Supplementation of G/PVA film in ZnONPs decreased the tensile strength (TS) from 2.97 MPa to 1.69 MPa. The addition of BCCE and ZnONPs increased the elongation at the break (EAB) of the enriched film by about 3%. The G/PVA/BCCE/ZnONPs film revealed the lowest water vapor permeability (WVP = 1.14 × 10−9 g·mm·Pa−1·h−1·mm−2) and the highest opacity (3.41 mm−1). The QUick, Easy, New, CHEap and Reproducible (QUENCHER) methodologies using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6- sulfonic acid) (ABTS) and cupric ion reducing antioxidant capacity (CUPRAC) were applied to measure antioxidant capacity (AC) of the prepared films. The incorporation of BCCE and ZnONPs into G/PVA films enhanced the AC by 8–144%. The films containing ZnONPs and a mixture of BCCE and ZnONPs inhibited the growth of three Gram-positive bacterial strains. These nanocomposite films with desired functional properties can be recommended to inhibit microbial spoilage and oxidative rancidity of packaged food. 相似文献
33.
34.
Ursula Torres-Parejo Jesús R. Campaña M. Amparo Vila Miguel Delgado 《Knowledge and Information Systems》2014,40(2):315-347
This paper presents a new approach to information retrieval from non-structured attributes in databases, which involves the processing of text attributes. To make retrieval more effective, frequent text sequences are extracted and mathematically represented as intermediate forms which permit a clearer and more precise definition of operations on texts. These intermediate forms appear to users in the form of tag clouds to facilitate content identification, exploration, and querying. In this sense, tag cloud visualization is a simple, user-friendly visual interface to data. This paper proposes a theoretical model for the representation of frequent text sequences and their operations as well as a general procedure for generating tag clouds from text attributes in databases. The tag clouds thus obtained were compared with conventional tag clouds composed of single terms. Our study showed that automatically generated multi-term tag clouds provide better results than mono-term tag clouds. 相似文献
35.
Jana Velde Ursula Kowalsky Tim Zümendorf Dieter Dinkler 《Computational Materials Science》2009,46(2):352-357
In order to describe the time-dependent inelastic behavior of steel structures up to failure, a material model is developed within the framework of thermodynamics considering viscoplastic material behavior, isotropic hardening, softening, and isotropic ductile damage. Since softening and damage lead to localization of deformations, the model is extended by a non-local implicit gradient formulation. An additional gradient equation is formulated for the local damage variable in order to achieve results independent of the finite-element discretization. The approach is verified by 3D-structural analysis of CT-specimens. 相似文献
36.
Laughing at oneself is considered a core component of the sense of humor in the theories of several authors. In McGhee's (1996) eight-step-training program of the sense of humor, laughing at oneself constitutes one of the most difficult levels. However, until now, only little empirical evidence on laughing at oneself exists. Using a multimethod approach, in the current study, 70 psychology students and a total of 126 peers filled in the Sense of Humor Scale (SHS, McGhee, 1996), containing as a subscale “Laughing at oneself”. In addition, the participants answered the Trait and State forms of the State-Trait-Cheerfulness-Inventory (STCI, Ruch, K?hler, & van Thriel, 1996; Ruch, K?hler, & van Thriel, 1997). They then were confronted with six distorted images of themselves. Facial responses of the participants were videotaped and analyzed using the Facial Action Coding System (FACS, Ekman, Friesen, & Hager, 2002). Four indicators of exhilaration were examined: (a) experienced funniness, (b) AU12 smiles, (c) Duchenne displays, and (d) laughter. Furthermore, fake and masking smiles were studied. Results demonstrated that self- and peer reports of “laughing at oneself” converged moderately. All four indicators of exhilaration were shown, but funniness and laughter seemed to be the most strongly related indicators. Trait cheerfulness and (low) seriousness, and a cheerful mood state formed further characteristics of persons who laugh at themselves. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
37.
Taisa Venäläinen Ursula Schwab Jyrki Ågren Vanessa de Mello Virpi Lindi Aino-Maija Eloranta Sanna Kiiskinen David Laaksonen Timo A. Lakka 《Lipids》2014,49(5):467-479
Plasma fatty acid (FA) composition is known to be an indicator of dietary fat quality, but the associations of other dietary factors with plasma FA composition remain unknown in children. We investigated the cross-sectional associations of food consumption with the proportions of FA and estimated desaturase activities in plasma cholesteryl esters (CE) and phospholipids (PL) among children. The subjects were a population sample of 423 children aged 6–8 years examined at baseline of The Physical Activity and Nutrition in Children (PANIC) Study. We assessed food consumption by food records and plasma FA composition by gas chromatography. We used linear regression models adjusted for age, sex, physical activity and total energy intake to analyze the associations. A higher consumption of vegetable oil-based margarine (fat 60–80 %) was associated with a higher proportion of linoleic and α-linolenic acids in plasma CE and PL. A higher consumption of high-fiber grain products was related to a lower proportion of oleic acid in CE and PL. The consumption of candy was directly associated with the proportion of palmitoleic and oleic acid in plasma CE. The consumption of vegetable oil-based margarine was inversely associated with estimated stearoyl-CoA-desaturase activity in plasma CE and PL and the consumption of candy was directly related to it in plasma CE. The results of our study suggest that plasma FA composition is not only a biomarker for dietary fat quality but also reflects the consumption of high-fiber grain products and foods high in sugar among children. 相似文献
38.
The choice of statistical distributions characterising microbial counts is essential in risk assessment and risk management. While the lognormal distribution has been long used to directly model the microbial data obtained from food samples, it does not allow for complete absence of microorganisms in a sample. Within a heterogeneous Poisson theoretical interpretation, a gamma or a lognormal population distribution for the unknown microbial concentration and a Poisson measurement distribution produces a discrete Poisson-gamma (λ, 1/k) or a Poisson-lognormal (μ,σ) distribution of observed plate counts. The capability of both distributions to deal with clustering was compared using six data sets of variable proportion of zero counts: total viable counts, coliforms and Escherichia coli on pre-chill and post-chill beef carcasses. Whereas the Poisson-lognormal distribution fitted better to the high counts data sets, the Poisson-gamma distribution represented the low counts data sets (13–81% zero counts) by far better than the Poisson-lognormal – which invariably tended to have a longer tail, an overestimated mean log and a lower predicted probability of zero counts. The inverse close relationship between the observed proportion of zero counts in the data set and the fitted dispersion factor 1/k suggested the possibility of obtaining a first approximation of 1/k by this means. Finally, in absence of zero counts, it was demonstrated that fitting a Poisson-lognormal to the observed plate count data can be closely approximated by the common practice of fitting a simple normal distribution to the back-calculated ‘unobserved’ mean concentrations in log CFU/g. 相似文献
39.
Stefan Kwiatkowski Ursula Thielen Phyllis Glenney Colm Moran 《Journal of the Institute of Brewing》2009,115(2):151-158
Much research has been carried out over the years examining cell wall glucans from Saccharomyces cerevisiae and this study further examines aspects of the binding of (1r?4)‐α‐D‐glucan in the yeast cell wall, using a number of isolation techniques as well as monoclonal antibodies able to recognize a mixed (1r?4)‐α‐D‐glucan/(1r?6)‐β‐D‐glucan. Extraction of purified glucan, from S. cerevisiae cell wall, with 0.1N HCl, at 80°C for 6 h, released into the solution (1r?4)‐α‐D‐glucan and (1r?6)‐β‐D‐glucan as the major polysaccharides, along with an insoluble pellet highly enriched in (1r?3)‐β‐D‐glucan. The released (1r?4)‐α‐D‐glucan was composed of a high molecular size >100 kDa fraction (7.2% w/w) and a medium 5–50 kDa polysaccharide (10.2% w/w), with the (1r?4)‐α‐D‐glucan covalently bound to the (1r?6)‐β‐D‐glucan. The average molar ratio of the α:β glucan was 47: 53 in this mixed polysaccharide. The structure of this polysaccharide was different from the structure of plant starch or animal glycogen as monoclonal antibodies specific to yeast (1r?4)‐α‐D‐glucan/(1r?6)‐β‐D‐glucan did not recognize the plant starch or animal glycogen standards. 相似文献
40.
Observed 72 infants aged 12, 18, and 24 mo in the presence of their mothers and 2 adult female strangers to assess their willingness to initiate proximal interaction (PI) with unfamiliar adults. Mothers and strangers were asked to be warmly responsive to infant overtures but not to invite interaction from the infant. A majority of the infants at the 3 ages initiated PI with one or both strangers, often repeatedly. For those who engaged in 2 or more PI bouts with the strangers, a significant upward trend in bout duration and intensity was noted. Older infants gave more toys to the strangers and initiated more mutual play. Stranger–mother distance affected amount of proximity, not PI. Mother–stranger conversation was associated with less PI with the conversing stranger. At all ages infants sought more PI with their mothers than with the strangers. Although infants initiated an appreciable amount of PI with the strangers during the 40-min observation, comparison with other studies indicates that a stranger who takes the initiative by inviting play can establish more rapport much sooner. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献