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21.
M Karr M Mira J Causer J Earl G Alperstein F Wood MJ Fett J Coakley 《Canadian Metallurgical Quarterly》1997,67(6):432-436
Paediatric reference intervals for blood concentrations of certain nutrients are often based on either adult data or are derived from small samples of young children. Biochemical data were obtained from 467 randomly selected, healthy preschool children aged 9-62 months in Sydney, Australia. Data were obtained for plasma vitamins A, E and beta-carotene and for serum zinc, retinol-binding protein and prealbumin. Reference intervals based on the 2.5 and 97.5 centiles for age groups 9-23, 24-35, 36-47, 48-62 months and for the total group (9-62 months) were calculated. The 2.5-97.5 centiles for the whole group were: vitamin A, 0.7-1.8 mumol/l (20.05-51.56 micrograms/dl); vitamin E, 8-30 mumol/l (0.34-1.29 mg/dl); beta-carotene, 0.1-1.1 mumol/l (5.4-59.0 micrograms/dl); zinc, 9-19 mumol/l (58.8-124.2 micrograms/dl); retinol-binding protein, 14-36 mg/l; prealbumin, 104-264 mg/l. The reference intervals reported are consistent with the findings of a number of smaller studies and are likely to be an accurate reflection of the true intervals for healthy preschool children in western developed countries. 相似文献
22.
A technique to suppress higher harmonics in side-coupled ring bandpass filters is proposed and demonstrated. The proposed technique basically consists of optimising the ring shape and the excitation stage of the complete filter structure in order to mitigate the excitation of the resonant modes that generate the second-harmonic filter resonances. A harmonic suppression ratio for the second harmonic greater than 25 dB in a flat bandpass filter centred at 2.5 GHz is experimentally demonstrated. 相似文献
23.
Channeling-enhanced electron energy-loss spectroscopy is applied to determine the polarity of ultra-small nitride semiconductor nanocolumns in transmission electron microscopy. The technique demonstrates some practical advantages in the nanostructure analysis, especially for feature sizes of less than 50 nm. We have studied GaN and (Al, Ga)N nanocolumns grown in a self-assembled way by molecular beam epitaxy directly on bare Si(111) substrates and on AlN buffer layers, respectively. The GaN nanocolumns on Si show an N polarity, while the (Al, Ga)N nanocolumns on an AlN buffer exhibit a Ga polarity. The different polarities of nanocolumns grown in a similar procedure are interpreted in terms of the specific interface bonding configurations. Our investigation contributes to the understanding of polarity control in III-nitride nanocolumn growth. 相似文献
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Nicolas Terrade Ronan Noël Romain Couillaud Ramón Mira de Orduña 《Food research international (Ottawa, Ont.)》2009,42(3):363-367
Growth and activity of lactic acid bacteria is crucial for the production and quality of grape wines but studying their metabolism is difficult in wines or complex laboratory media because of the undefined substrate pools. This work presents a new chemically defined medium that meets the fastidious nutritional requirements of wine lactic acid bacteria and yields rapid and strong growth. The new medium is composed of 44 constituents and a precise protocol is provided for its preparation. Maximum specific growth rates and growth yields of the wine strains studied were comparable to those obtained in common laboratory media, and the new medium allows for various modifications, such as changing the medium pH to the wine range, addition of L-malic acid or utilization of different carbon sources while maintaining growth of wine lactic acid bacteria. The medium was successfully tested with 22 wine strains of the genera Oenococcus, Lactobacillus and Pediococcus. It is suggested that this chemically defined medium be considered for the investigation of the nutritional requirements and metabolism of wine lactic acid bacteria. 相似文献
26.
This paper is devoted to a study of the sintering of two Y2O3 powders in the temperature range where only minor densification occurs. Two powders have been examined; one powder, Y2O3-A, was obtained by decomposition of hydroxide, because earlier examinations showed [11] that use of this powder resulted in the highest densities of samples in the sintering temperature range from 1300 to 1900° C. The second powder, Y2O3-D, was purchased externally. In order to ensure that the pores in the Y2O3-A compacts closed as late as possible, the heating rates up to the appropriate temperatures (1000 to 1400° C) were varied in the range 0.013 to 6° C sec–1. The results obtained show that the heating rate in this temperature range, for the powder obtained by decomposition of hydroxide, is of primary importance in the densification of the material, and that cessation of shrinkage was not observed in the period of 240 min. 相似文献
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The present study analyzed the antioxidative effects of various beverages, in vitro, and also the effect of short term consumption of beverages richest in polyphenols by healthy subjects on serum anti-atherogenic properties. Healthy subjects consumed 250 mL of the selected beverages for 2 h, or daily, for up to 1 week.We hypothesized that differences in the anti-atherogenic properties of the studied beverages could be related, not only to the quantity of polyphenols, but also to their quality. Furthermore, we hypothesized that consumption of these juices by healthy subjects for just a short-term, will increase their serum anti-atherogenic properties, as was demonstrated previously in long-term consumption studies.Of 35 beverages studied, both 100% Wonderful-variety pomegranate and 100% black currant juices were the most potent antioxidants in vitro, as they inhibited copper ion-induced LDL oxidation by up to 94% and AAPH-induced serum lipid peroxidation by up to 38%. Furthermore, they increased in vitro serum paraoxonase 1 (PON1) lactonase activity by up to 51%. Consumption of five selected polyphenol rich beverages by healthy subjects increased serum sulfhydryl group (SH) levels and serum PON1 activities after 2 h, and more so after 1 week of drinking these beverages. These effects were most pronounced after the consumption of 100% Wonderful-variety pomegranate and 100% black currant juices. In conclusion, polyphenolic-rich juices with impressive in vitro antioxidant properties, also demonstrate antioxidant effects in vivo when analyzed for short term consumption. In this respect, 100% Wonderful-variety pomegranate and 100% black currant juices were most the potent. 相似文献
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