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11.
Samples of {4-(dimethylamino) stilben Z & E 4'-yl} dimesityl borane (BNS) were synthesised and investigated for their non-linear optical properties. The results show that the quadratic hyperpolarisability of the Z-isomer is smaller than that of the E-isomer, the beta value found for the latter being as high as 60 × 10?30 esu.  相似文献   
12.
Abstract: This study aimed to determine dietary vitamin D intake of U.S. Americans and Canadians and contributions of food sources to total vitamin D intake. Total of 7‐ or 14‐d food intake data were analyzed for vitamin D by a proprietary nutrient assessment methodology that utilized food intake data from the Natl. Eating Trends® service, portion size data from NHANES 1999–2004, and nutrient values using the Univ. of Minnesota's Nutrition Data System for Research software. Study participants were 7837 U.S. Americans and 4025 Canadians, ≥2‐y‐old males and females. The main outcome measures were total dietary vitamin D intake, percent contribution of foods to total vitamin D intake, and vitamin D intake by cereal and breakfast consumption habits. ANOVA was used to determine differences in means or proportions by age and gender and according to breakfast consumption habits. Mean vitamin D intake ranged from 152 to 220 IU/d. Less than 2% of participants in all age groups from the United States and Canada met the 2011 Recommended Daily Allowance (RDA) for vitamin D from foods. Milk, meat, and fish were the top food sources for vitamin D for both Americans and Canadians. Ready‐to‐eat (RTE) cereal was a top 10 source of vitamin D for Americans but not Canadians. Vitamin D intake was higher with more frequent RTE cereal and breakfast consumption in both countries, largely attributable to greater milk intake. Practical Application: Most U.S. Americans and Canadians do not meet the 2011 Inst. of Medicine recommended daily allowance (RDA) for vitamin D for their age groups from foods. Increasing breakfast and cereal consumption may be a useful strategy to increase dietary vitamin D intake to help individuals meet the RDA for vitamin D, particularly by increasing milk intake. However, it is likely that additional food fortification or vitamin D supplementation is required to achieve the RDA.  相似文献   
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The growth of psychrotolerant aerobic spore-forming bacteria during refrigerated storage often results in the spoilage of fluid milk, leading to off-flavors and curdling. Because of their low toxicity, biodegradability, selectivity, and antimicrobial activity over a range of conditions, glycolipids are a novel and promising intervention to control undesirable microbes. The objective of this study was to determine the efficacy of a commercial glycolipid product to inhibit spore germination, spore outgrowth, and the growth of vegetative cells of Paenibacillus odorifer, Bacillus weihenstephanensis, and Viridibacillus arenosi, which are the predominant spore-forming spoilage bacteria in milk. For spore germination and outgrowth assays, varying concentrations (25–400 mg/L) of the glycolipid product were added to commercial UHT whole and skim milk inoculated with ~4 log10 spores/mL of each bacteria and incubated at 30°C for 5 d. Inhibition of spore germination in inoculated UHT whole milk was only observed for V. arenosi, and only when glycolipid was added at 400 mg/L. However, concentrations of 400 and 200 mg/L markedly inhibited the outgrowth of vegetative cells from spores of P. odorifer and B. weihenstephanensis, respectively. No inhibition of spore germination or outgrowth was observed in inoculated UHT skim milk for any strain at the concentrations tested (25 and 50 mg/L). The effect of glycolipid addition on vegetative cell growth in UHT whole and skim milk when inoculated with ~4 log10 cfu/mL of each bacteria was also determined over 21 d of storage at 7°C. Glycolipid addition at 50 mg/L was bactericidal against P. odorifer and B. weihenstephanensis in inoculated UHT skim milk through 21 d of storage, whereas 100 mg/L was needed for similar control of V. arenosi. Concentrations of 100 and 200 mg/L inhibited the growth of vegetative cells of B. weihenstephanensis and P. odorifer, respectively, in inoculated UHT whole milk, whereas 200 mg/L was also bactericidal to B. weihenstephanensis. Additional studies are necessary to identify effective concentrations for the inhibition of Viridibacillus spp. growth in whole milk beyond 7 d. Findings from this study demonstrate that natural glycolipids have the potential to inhibit the growth of dairy-spoilage bacteria and extend the shelf life of milk.  相似文献   
14.
A number of environmental stressors have been hypothesized as responsible for recent increases in limb malformations in several species of North American amphibians. The purpose of this study was to generate dose-response data suitable for assessing the potential role of solar ultraviolet (UV) radiation in causing limb malformations in a species in which this phenomenon seemingly is particularly prevalent, the northern leopard frog (Rana pipiens). Frogs were exposed from early embryonic stages through complete metamorphosis to varying natural sunlight regimes, including unaltered (100%) sunlight, sunlight subjected to neutral density filtration to achieve relative intensities of 85%, 75%, 65%, 50%, and 25% of unaltered sunlight, and sunlight filtered with glass or acrylamide to attenuate, respectively, the UVB (290-320 nm) and UVB plus UVA (290-380 nm) portions of the spectrum. The experiments were conducted in a controlled setting, with continual monitoring of UVB, UVA, and visible light to support a robust exposure assessment. Full sunlight caused approximately 50% mortality of the frogs during early larval development; no significant treatment-related mortality occurred under any of the other exposure regimes, including 100% sunlight with glass or acrylamide filtration. There was a dose-dependent (p < 0.0001) induction of hindlimb malformations in the frogs, with the percentage of affected animals ranging from about 97% under unaltered sunlight to 0% in the 25% neutral density treatment. Malformations were comprised mostly of missing or truncated digits, and generally were bilateral as well as symmetrical. Filtration of sunlight with either glass or acrylamide both significantly reduced the incidence of malformed limbs. The estimated sunlight dose resulting in a 50% limb malformation rate (ED50) was 63.5%. The limb ED50 values based on measured sunlight intensities corresponded to average daily doses of 4.5 and 100 Wh x m(-2) for UVB and UVA, respectively. Exposure to sunlight also resulted in increased eye malformations in R. pipiens, however, the dose-response relationship for this endpoint was not monotonic. The results of this study, in conjunction with measured or predicted exposure data from natural settings, provide a basis for quantitative prediction of the risk of solar UV radiation to amphibians.  相似文献   
15.
Wheat (Triticum aestivum L.) plays a central role in the health and nutrition of humans. Yet, little is known about possible flavor differences among different varieties. We have developed a model system using the house mouse (Mus musculus L.) to determine feeding preferences as a prelude to extending results to human sensory analysis. Here, we examine the application of a single‐elimination tournament design to the analysis of consumption preferences of a set of hard red and hard white spring wheat varieties. A single‐elimination tournament design in this case pairs 2 wheat varieties and only 1 of the 2 is advanced to further tests. Preferred varieties were advanced until an overall “winner” was identified; conversely, less desirable varieties were advanced such that an overall “loser” was identified. Hollis and IDO702 were the winner and loser, respectively, for the hard red varieties, and Clear White 515 and WA8123 were the winner and loser, respectively, for the hard white varieties. When using the more powerful protocol of 14 mice and a 4?d trial, differences in mean daily consumption preferences of 2 varieties were separated at P‐values as small as 2 × 10?8. The single‐elimination tournament design is an efficient means of identifying the most and least desirable varieties among a larger set of samples. One application for identifying the 2 extremes in preference within a group of varieties would be to use them as parents of a population to identify quantitative trait loci for preference.  相似文献   
16.
As the climate changes, farmers in developing countries seek to employ strategies to help them sustain food production. The objectives of this paper were to identify adaptation strategies in response to climate change and the determinants for their adoption, and to explore the impact of these strategies on food security. The analysis was based on a survey of 900 small-scale farmers in a semi-arid (Dodoma) and a semi-humid (Morogoro) region in Tanzania. Farmers in the semi-humid region tended to diversify their crops, i.e. added additional crop types. Given the more challenging environment in the semi-arid region, farmers there changed their portfolio of crops, i.e. substituted some crops or cultivars with others. Logistic regressions highlighted higher tolerance to risk, land ownership, education and experiences of farmers as drivers of adoption, while income diversification had a negative effect. The propensity score matching approach showed that adopters of climate-smart strategies are on-average more food-secure. These users showed a more diverse pattern of food consumption, greater protein intake and better economic access to food. Changing crop portfolios can help households to cope with climate-related shocks such as droughts and thus appears to be the best performing strategy, especially in terms of more stable food provisioning throughout the year.  相似文献   
17.
The seed lipids of three species ofEntandraphragma (Meliaceae) contain the largest proportion (31–50%) ofcis-vaccenic acid ever found in nature. The acid is not indicative of the family as a whole and is found as a major fatty acid in the seed of only one additional species, besidesEntandraphragma, out of the 30 analyzed from this family. With the total oil comprising between 45 and 62% ofEntandraphragma seed, these species should be considered as a source of undecadioic acid for the production of nylon 11.  相似文献   
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The effects of fat, type of natural cheese, and adjunct process cheese ingredients were evaluated to determine factors that contribute to the botulinal safety of reduced-fat (RF) process cheese products stored at 30 degrees C. In the first set of experiments, pasteurized process cheese products (PPCPs) were formulated using full-fat (FF) Cheddar, 30% RF Cheddar, or skim milk (SM) cheese as cheese-base types and were standardized to 59% moisture, pH 5.75, 2.8 or 3.2% total salts, and 15 to 19% fat. Subsequent trials evaluated the effect of fat levels and adjunct ingredients in PPCPs made with SM, RF, and FF cheese (final fat levels, less than 1, 13, and 24%, respectively). When fat levels of PPCPs were comparable (15.1, 19.1, and 16.2 for product manufactured with SC, RE and FF cheese, respectively), botulinal toxin production was delayed for up to 2 days in PPCPs formulated with SM compared with RF or FF cheese; however, the effect was not statistically significant. When fat levels were reduced to less than 1% in SM PPCPs, toxin production was delayed 2 weeks in products made with SM compared with RF or FF cheese manufactured with 13 or 24% fat, respectively. The antibotulinal effect of adjunct ingredients varied among the products manufactured with different fat levels. Sodium lactate significantly delayed toxin production (P < 0.05) for all fat levels tested, whereas beta-glucan fat replacer did not delay toxin production. An enzyme-modified cheese used as a flavor enhancer significantly delayed toxin production (P < 0.05) in SM (less than 1% fat) products but had little to no inhibitory effect in RF (13% fat) and FF (24% fat) cheese products. Similarly, monolaurin increased the time to detectable toxin in SM products but was ineffective in RF or FF cheese products. These results verify that RF PPCPs exhibit greater safety than FF products and that safety may be enhanced by using certain adjunct ingredients as antimicrobials.  相似文献   
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