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31.
A new conjugated trans,trans-diunsaturated acetylenic acid (17%), found for the first time in nature as a main component of the seed oil of Tanacetum (Chrysanthemum) corymbosum, was shown to be octadeca-8t,10t-dien-12-ynoic acid. Another already known naturally occurring acetylenic acid, crepenynic acid (10%), was found also in the
seed oil. The structure of this new unusual fatty acid was confirmed by chromatographic (thin-layer chromatography, gas chromatography,
high-performance liquid chromatography) and spectroscopic (infrared, ultraviolet, mass spectrometry) methods by using different
chemical derivatizations (deuteration, preparation of picolinyl ester, dimethyloxazoline, and maleic anhydride adduct). 相似文献
32.
Flocs are irregularly shaped suspended particles of complex structure and composition that occur naturally in aquatic systems. In water treatment facilities, the settling of flocs is extremely important. Transmission electron microscopy was used to quantify the formation of a nano‐scale surface layer on flocs from two laboratory bioreactors modelling a biological wastewater treatment facility. By comparing different floc populations, we demonstrated that flocs that settled quickly out of wastewater had a significant amount of this layer, whereas those with little nano‐scale surface layer had poor settling properties. This morphological feature of floc ultrastructure may permit engineering manipulations that promote floc settling. 相似文献
33.
J. T. Carstensen Myron Slotsky Dorothy Dolfini 《Drug development and industrial pharmacy》1989,15(13):2131-2152
The strategic decisions regarding package stability in an NDA should be thought out even before the IND stage (hence the inversion of the order of the words NDA and IND in the title). The philosophy of clinical blister packaging is discussed as are the tests necessary to ensure perfection of seal. The principles of molecular and pinhole moisture permeation are discussed. Suggested fractional factorial schemes for package testing are presented 相似文献
34.
Frye Douglas; Clark Andrew; Watt Dorothy; Watkins Chris 《Canadian Metallurgical Quarterly》1986,22(2):213
Used a computer-based task to investigate the problem that young children have in constructing diagonals. The computer made it feasible to change how lines of different orientations had to be formed. It was predicted that if diagonals are difficult to construct because of the operations required to conceptualize them, then changing how they had to be formed might make it possible for children to construct diagonals better than horizontals and verticals. 20 5-yr-olds, 20 8-yr-olds, and 20 undergraduates attempted to construct horizontal, vertical, 45° left diagonal, and 45° right diagonal lines in either horizontal/vertical-easy or diagonal-easy configurations of the apparatus. Results support the operational explanation of the oblique effect. The 5-yr-olds performed in accordance with the configuration of the drawing system. On the whole, they could not make diagonals in the horizontal/vertical-easy configuration, thus demonstrating the oblique effect. When diagonals were made easy to produce, 5-yr-olds could form them but had difficulty with horizontals and verticals, indicating a nonoblique effect in the diagonal-easy configuration. There was only an oblique effect with the 8-yr-olds. Undergraduates made virtually no errors on any of the lines. Findings confirm the claim that the difficulty that the 5-yr-olds had was in combining separate spatial components. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
35.
36.
Gloria A. Smart Marjorie Warrington Dorothy Dellar John C. Sherlock 《Journal of the science of food and agriculture》1983,34(6):627-637
Following earlier work, detailed studies have been carried out on the lead uptake of individual foods from soft and hard water containing various amounts of lead. Experiments have also been made to determine whether solutions of lead nitrate in distilled water simulate the behaviour of water containing naturally present lead. The effect of length of cooking time, weight/volume ratio and salt addition have been studied, as well as the depostion of lead on to cooking vessels. In general, green vegetables, carrots, rice and spaghetti were found to take up more lead than do other foods. The difference in uptake observed between hard and soft waters varied according to the particular food being studied. Uptake from lead nitrate solutions showed a very similar pattern to uptake from hard water containing naturally present lead. Equilibrium was reached after only 5 min cooking for cabbage and spaghetti. Varying the solid/volume ratio for cabbage affected the uptake of lead from water, but the addition of sodium chloride or sodium bicarbonate had little effect on lead uptake. There was no sign of saturation in uptake of lead by cabbage from solutions of 11 mg litre?1 lead as lead nitrate. Deposition of lead occurred on both aluminium and glass saucepans, and cleaning was more effective in removing lead from glass saucepans. Results obtained from the analysis of diets in a small population at Ayr confirmed those obtained previously by laboratory experiments. 相似文献
37.
Irina Stepanov Joni Jensen Dorothy Hatsukami Stephen S Hecht 《Nicotine & tobacco research》2006,8(2):309-313
New tobacco products, designed to attract consumers who are concerned about the health effects of tobacco, have been appearing on the market. Objective evaluation of these products requires, as a first step, data on their potentially toxic constituents. Tobacco-specific nitrosamines (TSNAs) are an important class of carcinogens in tobacco products, but virtually no data were available on their levels in these products. In the present study, we analyzed several new products-Ariva, Stonewall, Exalt, Revel, Smokey Mountain, and Quest-for TSNAs and compared their TSNA levels with those in nicotine replacement products and conventional smokeless tobacco and cigarette brands. TSNAs were not detected in Smokey Mountain, which is a tobacco-free snuff product. The lowest levels among the new products containing tobacco were in Ariva and Stonewall (0.26-0.28 microg/g wet weight of product). The highest levels in the new products were found in Exalt (3.3 microg/g tobacco), whereas Revel and Quest had intermediate amounts. Only trace amounts were found in nicotine replacement products, and conventional brands had levels consistent with those reported in the literature. These results demonstrate that TSNA levels in new tobacco products range from relatively low to comparable with those found in some conventional brands. 相似文献
38.
Akiya Kozawa Hidehiko Oho Mitsuru Sano Dorothy Brodd Ralph Brodd 《Journal of power sources》1999,80(1-2):12-16
Based on the previous success of adding ultra-fine carbon–PVA (polyvinyl alcohol) colloid solution to restore performance of weak batteries, a large scale test programme of practical batteries including those used in forklift, golf cart, taxi cab, truck and bus applications from 150 companies was carried out. More than 95% of the tested batteries exhibited excellent recovery in performance parameters including the specific gravity (S.G.), voltage and operation time (Ah capacity). The work reported here includes basic research studies to understand better the beneficial action of the carbon–PVA colloid additive. 相似文献
39.
Zuberbühler Klaus; Cheney Dorothy L.; Seyfarth Robert M. 《Canadian Metallurgical Quarterly》1999,113(1):33
Some animal vocalizations have been described as referential, or semantic, because individuals respond to them as if they designate some object or event. Alternatively, subjects may simply attend to the acoustic features of calls rather than their meanings. Field playback experiments on diana monkeys (Cercopithecus diana diana) tested these hypotheses using the calls of leopards and eagles and the males' alarm calls to these predators. In the experiment, 2 calls were played in sequence, separated by 5 min of silence, such that they were either (a) similar in acoustic and semantic features, (b) similar in semantic features only, or (c) different in both acoustic and semantic features. Subjects readily transferred habituation across acoustic but not semantic features, suggesting that they attended to the calls' underlying meanings. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
40.
This paper describes a data-driven approach to sensor data validation. The data originates from a network of sensors embedded in an indoor environment such as an office, home, factory, public mall or airport. Data analysis is performed to automatically detect events and classify activities taking place within the environment. Sensor failure and in particular intermittent failure, caused by electrical interference, undermines the inference processes. PCA and CCA are compared for detecting intermittent faults and masking such failures. The fault detection relies on models built from historical data. As new sensor observations are collected the model is updated and compared to that previously estimated, where a difference is indicative of a failure. 相似文献