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121.
Hanna Salminen Marina Heinonen Eric A. Decker 《Journal of the American Oil Chemists' Society》2010,87(4):419-428
The purpose of this study was to evaluate the effects of berry phenolics, in this case, black currant (Ribes nigrum) anthocyanins and raspberry (Rubus idaeus) ellagitannins, in the presence of continuous phase β-lactoglobulin (β-Lg), on the oxidative stability of Brij 35-stabilized
corn oil-in-water emulsions. The extent of lipid oxidation in emulsions was measured by determining the formation of lipid
hydroperoxides and hexanal, and extent of protein oxidation by monitoring the loss of tryptophan and cysteine residues in
the continuous phase β-Lg. Berry phenolics at concentration levels of 20 and 50 μM were able to prevent lipid oxidation with
and without β-Lg in the aqueous phase. The results show that a combination of β-Lg and berry phenolics was more efficient
in inhibiting hexanal formation than either component alone. Synergistic effects on antioxidant activity toward hexanal were
observed only at the 20 μM levels of berry phenolics in combination with continuous phase β-Lg. The berry phenolics were also
able to inhibit the oxidation of tryptophan and cysteine residues of β-Lg. The results show that the amino acid residues were
oxidized prior to the propagation of lipid oxidation. This suggests that these amino acids were able to inhibit fatty acid
scission. The information gained from this study would be useful in protecting emulsion-based food products from oxidative
deterioration. 相似文献
122.
123.
Trace metals, PCB congeners and DDT homologues were determined in composite sediment samples collected from 10 representative sites along the river Po in two separate seasons. The aim was to identify the most anthropogenically impacted areas for future monitoring programmes and to aid development of Italian sediment quality criteria. The surface samples were collected during low flow conditions. Trace metal concentrations were assayed by electrothermal (Cd, Co, Cr, Cu, Ni, Pb), flame (Fe, Mn, Zn) or hydride generation (As) atomic absorption spectrometry after microwave assisted acid digestion. Hg was determined on solid samples by automated analyser. Organic microcontaminants were determined by gas-chromatography with 63Ni electron capture detector after Soxhlet extraction. Concentrations of trace metals, total PCB and DDT homologues showed two distinct peaks at the sites immediately downstream of Turin and Milan, respectively, and in each case decreased progressively further downstream. Principal component analysis identified three major factors (from a multi-dimensional space of 35 variables) which explained 85-90% of the total observed variance. The first and second factors corresponded to anthropogenic inputs and geological factors on sediment quality; the third included seasonal processes of minor importance. Sediment quality assessment identified Cd, Cu, Hg, Pb, Zn and organic microcontaminants as posing the most serious threats to river sediment quality. A reference site within the Po basin provided useful background values. Moderate pollution by organochlorine compounds was ascribed both to local sources and to atmospheric deposition. 相似文献
124.
Teplenko Marina A. Podchernyaeva Irina A. Panasyuk Alla D. 《Powder Metallurgy and Metal Ceramics》2002,41(3-4):154-161
We have studied the process of electrospark alloying of titanium alloy VT6 and steels with a composite material based on AlN ZrB2 with ZrSi2 additive. We have established that Al2SiO5 and ZrSiO4 forming in the coating directly during its formation play the role of a solid lubricant. Under optimal conditions for electrospark alloying of the titanium alloy, the coefficient of friction is 0.13, the wear is 6 m/km for a sliding velocity of 14 m/sec and a load of 2.56 MPa. Ceramics based on AlN ZrB2 can be recommended for use as wear-resistant and corrosion-resistant coatings. 相似文献
125.
Klibanoff Raquel S.; Levine Susan C.; Huttenlocher Janellen; Vasilyeva Marina; Hedges Larry V. 《Canadian Metallurgical Quarterly》2006,42(1):59
This study examined the relation between the amount of mathematical input in the speech of preschool or day-care teachers and the growth of children's conventional mathematical knowledge over the school year. Three main findings emerged. First, there were marked individual differences in children's conventional mathematical knowledge by 4 years of age that were associated with socioeconomic status. Second, there were dramatic differences in the amount of math-related talk teachers provided. Third, and most important, the amount of teachers' math-related talk was significantly related to the growth of preschoolers' conventional mathematical knowledge over the school year but was unrelated to their math knowledge at the start of the school year. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
126.
Bonatti Luca L.; Nespor Marina; Pe?a Marcela; Mehler Jacques 《Canadian Metallurgical Quarterly》2006,135(2):314
M. Pe?a, L. L. Bonatti, M. Nespor, and J. Mehler (see record 2002-06215-001) argued that humans compute nonadjacent statistical relations among syllables in a continuous artificial speech stream to extract words, but they use other computations to determine the structural properties of words. Instead, when participants are familiarized with a segmented stream, structural generalizations about words are quickly established. P. Perruchet, M. D. Tyler, N. Galland, and R. Peereman (see record 2004-21166-008) criticized M. Pe?a et al.'s work and dismissed their results. In this article, the authors show that P. Perruchet et al.'s criticisms are groundless. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
127.
Awareness is growing that fresh or minimally processed fruit and vegetables can be sources of disease-causing bacteria, viruses, protozoa, and helminths. Irrigation with poor-quality water is one way that fruit and vegetables can become contaminated with foodborne pathogens. Groundwater, surface water, and human wastewater are commonly used for irrigation. The risk of disease transmission from pathogenic microorganisms present in irrigation water is influenced by the level of contamination; the persistence of pathogens in water, in soil, and on crops; and the route of exposure. Groundwater is generally of good microbial quality, unless it is contaminated with surface runoff; human wastewater is usually of very poor microbial quality and requires extensive treatment before it can be used safely to irrigate crops; surface water is of variable microbial quality. Bacteria and protozoa tend to show the poorest survival outside a human host, whereas viruses and helminths can remain infective for months to years. Guidelines governing irrigation water quality and strategies to reduce the risk of disease transmission by foodborne pathogens in irrigation are discussed. 相似文献
128.
Franc Novak Marina Santo Zarnik Sre
ko Ma
ek 《Reliability Engineering & System Safety》2004,84(2):125-128
This article describes the implementation of early warning feature in an over-current protection module designed for limiting the surge-current in communication applications. The early warning signal is generated by a surge-current sensor and a temperature sensor mounted on the protection module. Described solution decreases fault latency and consequently improves the efficiency of the on-line fault detection mechanism. It can be used for diagnostic on-line monitoring in dependable adaptive computing systems. 相似文献
129.
Spectroscopic evaluation of the effect of a red microalgal polysaccharide on herpes-infected Vero cells 总被引:1,自引:0,他引:1
The sulfated polysaccharide obtained from a species of red microalga has proved to be a potent antiviral agent against various members of the herpes family. In the present study, we used microscopic Fourier transform infrared spectroscopy (FT-IR) to investigate differences between normal cells, those infected with herpes viruses, and infected cells treated with red microalgal polysaccharide. FT-IR enables the characterization of cell or tissue pathology based on characteristic molecular vibrational spectra of the cells. The advantage of microscopic FT-IR spectroscopy over conventional FT-IR spectroscopy is that it facilitates inspection of restricted regions of cell cultures or tissue. Our results showed significant spectral differences at early stages of infection between infected and noninfected cells, and between infected cells treated with the polysaccharide and those not treated. In infected cells, there was an impressive decrease in sugar content and a considerable increase in phosphate levels in conjunction with the infection progress. Our results also proved that sugars penetrated and accumulated inside cells treated with the red microalgal polysaccharide. These could have been sugar fragments of low molecular weight present in the polysaccharide solution, despite purification by dialysis. Such sugar accumulation might be responsible for a breakdown in the internal steps of the viral replication cycle. 相似文献
130.
Yagüe J Paradela A Ramos M Ogueta S Marina A Barahona F López de Castro JA Vázquez J 《Analytical chemistry》2003,75(6):1524-1535
The emergence of proteomics has placed great interest in the understanding of the mechanisms of MS/MS fragmentation of peptides under low-energy collision-induced dissociation. In this work, we describe the presence of anomalous fragments, which correspond to neutral loss elimination of internal amino acids from ions of the b series in quadrupole ion trap MS/MS spectra from naturally occurring peptides. Internal amino acid elimination occurred preferentially with aliphatic amino acids. The phenomenon was more apparent when doubly charged precursors were fragmented and was inhibited when peptides were N-acetylated at the N-terminus. Fragmentation of isomeric peptides where some internal amino acids were relocated in N-terminal position produced MSn spectra indistinguishable from those of the original peptides, indicating that some b ions underwent a structural rearrangement process. Formation of anomalous fragments required a minimum activation time. Our data are consistent with a nucleophile attack of the N-terminal nitrogen over the electrophilic carbonyl carbon at one peptide bond, forming a cyclic b ion intermediate that, by reopening at preferential sites, exposes internal amino acids to the C-terminal side. 相似文献