排序方式: 共有29条查询结果,搜索用时 31 毫秒
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C Maynou H Mestdagh Y Butruille M Lecomte-Houcke 《Canadian Metallurgical Quarterly》1997,16(2):146-151
This study investigates the extent to which sunscreens protect humans from ultraviolet (UV)-radiation-induced immunosuppression. In the presence of solar-simulated UV, three sunscreens with differing UVA transmission were assessed for their ability to protect the contact hypersensitivity (CHS) response to nickel of 16 nickel-allergic subjects. The sunscreens contained 2-ethylhexyl para-methoxycinnamate (cinnamate), cinnamate with oxybenzone, or cinnamate with zinc oxide, respectively. All had sun protection factors of 10 and hence inhibited UV erythema to similar extents. Volunteers were irradiated on their backs with suberythemal UV daily for 5 d after application of the sunscreens and their base lotion to different sites. Nickel-containing patches were then applied to both UV-treated sites and adjacent, unirradiated control sites. Erythema caused by nickel CHS at each site was quantitated 72 h later with a reflectance erythema meter. In comparison of the nickel reactions of irradiated and unirradiated skin, there was 35% mean immunosuppression in unprotected UV-treated skin. Significant immunosuppression also occurred at sites irradiated through the narrow-spectrum cinnamate-only sunscreen but was prevented by the two broad-spectrum sunscreens. To determine whether UV-induced suppression of the nickel response is specific for cell-mediated immunity or reflects suppression of nonspecific inflammation, a further 16 subjects were patch-tested with a skin irritant, sodium lauryl sulfate (SLS), following a sunscreen and irradiation protocol identical to that of the nickel volunteers. UV had no significant effect on SLS responses. We conclude that nickel patch testing is a valid means of assessing UV-induced immunosuppression in humans and that even with suberythemal UV, immune protection was provided only by sunscreens filtering both UVA and UVB. 相似文献
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Duyck Wouter; Anseel Frederik; Szmalec Arnaud; Mestdagh Pascal; Tavernier Antoine; Hartsuiker Robert J. 《Canadian Metallurgical Quarterly》2008,34(5):1317
In current cognitive psychology, naming latencies are commonly measured by electronic voice keys that detect when sound exceeds a certain amplitude threshold. However, recent research (e.g., K. Rastle & M. H. Davis, 2002) has shown that these devices are particularly inaccurate in precisely detecting acoustic onsets. In this article, the authors discuss the various problems and solutions that have been put forward with respect to this issue and show that classical voice keys may trigger several tens of milliseconds later than acoustic onset. The authors argue that a solution to this problem may come from voice keys that use a combination of analogue and digital noise (nonspeech sound) detection. It is shown that the acoustic onsets detected by such a device are only a few milliseconds delayed and correlate highly (up to .99) with reaction time values obtained by visual waveform inspection. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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F. Bertinchamps M. Treinen P. Eloy A.-M. Dos Santos M.M. Mestdagh E.M. Gaigneaux 《Applied catalysis. B, Environmental》2007,70(1-4):360-369
A previous investigation of the chlorobenzene combustion activity of VOx/TiO2, VOx–WOx/TiO2 and VOx–MoOx/TiO2 catalysts in the presence of NO pointed out the activation effect of NO. The suggested three-step mechanism based on catalytic performances data only was: (1) chlorobenzene is oxidized on the surface of the VOx phase (as described by Mars–van Krevelen), (2) NO gets oxidized to NO2, mainly on WOx and MoOx, and (3) the in situ produced NO2 assists O2 in the reoxidation of the VOx phase thus speeding up the oxidation step of the Mars–van Krevelen mechanism. The latter effect macroscopically corresponds to the observed increase of chlorobenzene conversion. This contribution aims at validating this hypothetical mechanism by pointing out the favourable occurrence of an oxidation of NO to NO2 on the WOx and MoOx phases and by pointing out the higher efficiency of NO2 than O2 to reoxidize the reduced VOx sites. In addition, the present contribution clearly demonstrates that, in the absence of NO, the chlorobenzene total oxidation occurred following the Mars–van Krevelen mechanism. Moreover, a thorough characterization of the oxidation state of the vanadium proving that the improvement of the catalyst activity brought by the simultaneous presence of NO and O2 is linked to the stronger reoxidation of the VOx active phase. Furthermore, plotting all the catalytic activity data versus the mean vanadium oxidation level clearly depicts, for the first time, the strong dependence between them. Under a mean vanadium oxidation level of 4.82 the catalyst is inactive while above 4.87 the activity is stabilized at a high level of conversion independent of the vanadium oxidation level. 相似文献
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Pieter?DijkstraEmail author Floris?Bex Henry?Prakken Kees?de?Vey Mestdagh 《Artificial Intelligence and Law》2005,13(1):133-151
This paper outlines a multi-agent architecture for regulated information exchange of crime investigation data between police forces. Interactions between police officers about information exchange are analysed as negotiation dialogues with embedded persuasion dialogues. An architecture is then proposed consisting of two agents, a requesting agent and a responding agent, and a communication language and protocol with which these agents can interact to promote optimal information exchange while respecting the law. Finally, dialogue policies are defined for the individual agents, specifying their behaviour within a negotiation. Essentially, when deciding to accept or reject an offer or to make a counteroffer, an agent first determines whether it is obligatory or permitted to perform the actions specified in the offer. If permitted but not obligatory, the agent next determines whether it is in his interest to accept the offer. 相似文献
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Mestdagh F De Meulenaer B De Clippeleer J Devlieghere F Huyghebaert A 《Journal of dairy science》2005,88(2):499-510
Light-induced degradation reactions in milk create a serious problem for the dairy industry because of the development of off-flavors, the decrease in nutritional quality, and the severity and speed by which these phenomena develop. Packaging materials are essential to avoid this particular deterioration of milk. Therefore, efforts are being made to design protective polyethylene terephthalate (PET) packages. In the present study, a number of PET bottles were compared for their ability to avoid photo-oxidation in UHT semi-skimmed milk. The milk was packed in 3 types of PET bottles: one transparent bottle provided with an active oxygen-binding inner layer, one bottle with perfect light barrier, and one transparent bottle provided with a UV-absorbing additive. During 2 storage experiments, running parallel to each other for 2 mo, chemical milk quality parameters such as fat oxidation, vitamin and protein degradation, oxygen consumption, and color change were monitored. A trained taste panel compared the sensory quality of the illuminated milk stored in these bottles, with milk perfectly protected against light and oxygen. In the first study, milk was continuously illuminated at room temperature. A comparison was made for milk under storage conditions that simulated those expected during display in retail and supermarkets. The results of the 2 shelf-life studies showed that an adequate light barrier was apparently sufficient to avoid the light-induced oxidation of milk during extended storage. Oxygen barriers, on the other hand, did not provide a significant protection, nor did bottles with UV filter. If wavelengths detrimental to riboflavin were not completely excluded by the packaging material, incoming light could still give rise to photo degradation of milk. Accordingly, riboflavin and vitamin A were gradually degraded, milk fat was photo-oxidized, oxygen dissolved in the milk was consumed, and the sensorial quality decreased significantly. 相似文献
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A new method allowing a reduction in the probability of clipping in discrete multitone (DMT)-based transceivers is described. The method does not use any kind of precoding and can easily be implemented within conventional DMT-transceivers. The main advantage of the proposed method is an improvement of system performance in terms of overall signal-to-noise ratios (SNRs): with the simplest implementation option of the proposed method, up to about 8 dB improvement in the SNR as compared with previously reported brute force clipping methods can be achieved 相似文献
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