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101.
This paper shows that fluorescence spectroscopy can measure both degradation of photosensitizers and formation of lipid oxidation products in light-exposed butter. The photosensitizers were already notably degraded after 4 h of light exposure, whereas fluorescent lipid oxidation products were detected after 5 d. The fluorescence measurements were highly correlated with sensory assessments of acidic and rancid flavor. Photosensitizer degradation is therefore a promising indirect indicator of the onset of lipid oxidation in butter. Sensory analysis and measurement of peroxide value showed that the level of lipid oxidation was significantly higher for butter stored in air compared with butter stored in nitrogen (N2). This might be explained by the formation of singlet oxygen from direct photooxidation and type II photosensitized oxidation. Addition of the singlet oxygen quencher β-carotene reduced the rancid flavor intensity in the air and N2 packages from 9.0 to 4.9 and from 6.5 to 4.7, respectively. Results indicate that lipid oxidation in the butter stored in N2 was mainly caused by type I photosensitized reactions, because addition of β-carotene had little effect on the rancid flavor intensity. 相似文献
102.
The gelatinolytic activity in muscle from Atlantic cod (Gadus morhua), spotted wolffish (Anarhichas minor) and Atlantic salmon (Salmo salar) was studied using gelatin SDS‐PAGE, gelatin affinity chromatography and enzyme inhibitors. These fish species are known to differ markedly in fillet softening and gaping post mortem. Atlantic cod, which is a promising species for cold water marine aquaculture, often shows such negative properties, particularly after being well fed. Gelatinolytic activity bands were present in all three species. Using gelatin chromatography and enzyme inhibitors, both serine proteinases and metalloproteinases were detected in wolffish and cod muscle, while only the latter were found in salmon muscle. Activation of the metalloproteinases by p‐aminophenylmercuric acetate (APMA) resulted in a shift in activity from higher to lower molecular weight, as is known for mammalian matrix metalloproteinases. In all three species the molecular weight of the metalloproteinases was lowered from approximately 80 to about 70 kDa by activating with APMA. Copyright © 2003 Society of Chemical Industry 相似文献
103.
A total of 48 pigs (11.4 and 107.2 kg initial and final weight) were used to evaluate increasing dietary levels of bacterial protein meal (BPM) produced on natural gas (0, 50, 100, or 150 g kg−1) on fatty acid composition, sensory properties, and susceptibility of pork to lipid oxidation. Increasing levels of BPM to diets increased the content of C16:1 fatty acids in backfat and muscle and total monounsaturated fatty acids in muscle, but decreased the content of polyunsaturated fatty acids and iodine value in backfat and muscle. Pigs fed diets containing BPM had reduced thiobarbituric acid reactive substances (TBARS) value in backfat and muscle, reduced intensity of odor and rancid odor and taste in pork after short-time storage, and reduced off-odor and off-taste after intermediate-time storage. To conclude, adding BPM to diets for pigs changed the fatty acid profile, improved the oxidative stability, and sensory quality of pork. 相似文献
104.
105.
Daniel B. Carr Anthony R. Olsen Suzanne M. Pierson Jean-Yves P. Courbois 《Data mining and knowledge discovery》2000,4(1):43-67
The paper introduces linked micromap (LM) plots for presenting environmental summaries. The LM template includes parallel
sequences of micromap, label, and statistical summary graphics panels with attention paid to perceptual grouping, sorting
and linking of the summary components. The applications show LM plots for Omernik Level II Ecoregions. The summarized United
States continental data includes USGS digital elevation, 30-year normal precipitation and temperature, and 8 million AVHRR
pixels classified into 159 types of land cover. One LM plot uses a line-height glyph to represent all 159 land cover percentages
per ecoregion. LM plots represent new visualization methodology that is useful in the data and knowledge based pattern representation
and knowledge discovery process. The LM plots focus on providing an orienting overview. The overview provides a starting place
for subsequent drilling down to what could otherwise be viewed as an overwhelming mass of data. The overview also provides
a starting place to learn about the intellectual structure that lies behind the notion of ecoregions and begins to connect
this abstract structure to quantitative methods. 相似文献
106.
JA Saidi DT Chang ET Goluboff E Bagiella G Olsen H Fisch 《Canadian Metallurgical Quarterly》1999,161(2):460-462
PURPOSE: Recent reports suggest declining sperm counts in the United States. These reports did not include all available data and did not account for geographic variations noted in prior studies. We examined all available data on U.S. sperm counts and evaluated whether geographic variations account for the decline suggested. MATERIALS AND METHODS: We reviewed all 29 U.S. studies from 1938 to 1996 reporting manually counted semen analyses of 9,612 fertile or presumably fertile men. We determined mean sperm concentrations by geographic location with weighted analysis of variance, and assessed any changes with time by linear regression analysis. RESULTS: Mean sperm concentrations from New York were significantly higher than from all other U.S. cities (98.6 versus 71.6 x 10(6) sperm per cc, respectively, p = 0.006). There has been no statistically significant change with time for mean sperm concentrations reported from New York (p = 0.49) or from U.S. cities other than New York (p = 0.62). Analysis without separating by location revealed a decline (p = 0.047). CONCLUSIONS: Sperm concentrations are highest in New York compared to other U.S. cities. When accounting for this geographic difference and examining all available data, there appears to be no significant change in sperm counts in the U.S. during the last 60 years. Further studies addressing the causes of geographic variations are needed. 相似文献
107.
There is a trend in current attitude research to move away from a simple uni-dimensional view of attitude, towards examining a more multivariate concept of attitude. An extensive array of attitudinal properties or dimensions has been provided, defined and categorised as ‘attitude strength’. Attitude strength has only recently been adapted as a conceptual framework for research in marketing and consumer studies. Our objective in this paper is to introduce some of the attitude strength concepts and literature in order to improve the measure and understanding of research dealing with measurement of food preferences, perceived food quality and satisfaction with food products, food suppliers, etc. The paper takes a particular focus upon problems in comprehending the middlemost choice or neutrality when measuring attitude items along a traditional bipolar semantic differential or a bipolar hedonic preference scale. Through several propositions, we have outlined how future research should note that both attitude ambivalence (mixed feelings) and non-attitude (lack of confidence in evaluation) could be threats to comprehending the middlemost response alternative on a questionnaire as neutral when measuring food attitudes or preferences in the traditional way. Our approach should also deal with some of the shortcomings of analysing attitude–behaviour consistency when modelling food consumption behaviour. 相似文献
108.
Chbat M.W. Grard E. Berthelon L. Jourdan A. Perrier P.A. Leclert A. Landousies B. Ramdane A. Parnis N. Jones E.V. Limal E. Poulsen H.N. Pedersen R.J.S. Flaaronning N. Vercauteren D. Puleo M. Ciaramella E. Marone G. Hess R. Melchior H. Parys W.V. Demeester P.M. Godsvang P.J. Olsen T. Hjelme D.R. 《Selected Areas in Communications, IEEE Journal on》1998,16(7):1226-1244
The European ACTS project optical pan-European network (OPEN) aims at assessing the feasibility of an optical pan-European overlay network, interconnecting major European cities by means of a mesh of high-capacity optical fiber links, cross-connected through transparent photonic nodes. Both the transmission links and the routing network elements rely on wavelength division multiplexing (WDM) all-optical technologies, such as wavelength translation. This paper presents results obtained in the following domains covered within the project: network topology considerations (optimization and dimensioning); network physical layer simulation; fabrications of packaged functional modules based on advanced optoelectronic devices; laboratory demonstrations of N×10 Gb/s transmission and routing; feasibility of an optical time division multiplexing/WDM (OTDM/WDM) interface; and the field implementation of a 4×4 multiwavelength crossconnect prototype, featuring all-optical space and wavelength routing. This implementation was realized in two cross-border field trials, one conducted between Norway and Denmark and the other between France and Belgium. The final results of the Norway to Denmark field trials are presented, featuring the successful cascade of three wavelength-translating optical crossconnects (OXCs), along with the transmission over 1000 km of a mix of standard/submarine cable links for four channels at 2.5 Gb/s 相似文献
109.
Surface waves radiate energy at discontinuities in the curvature of the guiding structure. By reciprocity, surface waves will be excited by plane waves incident upon such a discontinuity. Here, the problem of the radiation of a surface wave on a flat dielectric-coated perfect conductor incident upon an abrupt change to a dielectric-coated cylindrical conductor with a large radius of curvature is considered. The problem is formulated as an integral equation over the aperture of the discontinuity. Since the change in curvature is modest, an approximate perturbation solution to the integral equation is derived and the radiated field due to the discontinuity is found. This radiated field reduces to published results for an impedance surface approximation when that approximation is valid. The problem of mode conversion and associated radiation near higher mode cutoffs is also studied. It is found that near mode cutoffs, the higher order mode dominates the radiation pattern and causes the overall radiation pattern due to the discontinuity in curvature to be narrow and end fire. Away from cutoff, when all of the propagating bound modes are more tightly bound to the surface, the radiation pattern is less narrow and less end fire. For very tightly bound modes the pattern is nearly uniform. For dielectrics characterized by small permitivities, the changes in radiation pattern should be measurable 相似文献
110.
We report on adverse drug reactions to statins recorded internationally and in Norway. The use of HMG-CoA reductase inhibitors (statins) has increased with a factor of 30 in Norway over the period 1989-96. Recently published clinical trials conclude that statins are safe; adverse drug reactions being infrequent and non-serious. The reactions observed are mostly increased hepatic enzymes and myopathy. Data from the Norwegian spontaneous reporting system, and from WHO's international database covering the period of 1988-95, includes reports of adverse drug reactions relating to other organ systems, such as the nervous system, the gastrointestinal tract, skin and cardiovascular organs. Psychiatric disorders represent 15% of the reactions to statins in the Norwegian database. Reactions include aggression, nervousness, depression, anxiety, sleeping disorders and impotence. The pharmacological mechanisms are not elucidated, but may be an effect of falling serum cholesterol. 相似文献