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21.
Brominated flame retardants in Belgian home-produced eggs: levels and contamination sources 总被引:1,自引:0,他引:1
Covaci A Roosens L Dirtu AC Waegeneers N Van Overmeire I Neels H Goeyens L 《The Science of the total environment》2009,407(15):4387-4396
The extent and the sources of contamination with brominated flame retardants (BFRs), such as polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD), in home-produced eggs from free-foraging chicken of Belgian private owners were investigated. Various factors, such as seasonal variability, exposure of chickens through diet (kitchen waste) and soil, and elimination of BFRs through eggs and faeces were assessed. PBDEs were more important than HBCD in terms of concentrations and detection frequency. Concentrations of PBDEs and HBCD in Belgian home-produced eggs were relatively low and comparable with reported levels from other European countries and the US. The concentrations of PBDEs (sum of 13 congeners, including BDE 209) ranged between not detected and 32 ng/g lipid weight (lw), with medians of 3.0 and < 2.0 ng/g lw for the autumn 2006 and spring 2007 campaigns, respectively. When present, BDE 209 was the major PBDE congener (45% of sum PBDEs). When BDE 209 was not detected, the PBDE profile was composed of PentaBDE (BDE 99 and BDE 47), with, in some cases, higher contribution of OctaBDE (BDE 183 and BDE 153). HBCD was also detected (< 0.4 and 2.9 ng/g lw for the autumn 2006 and spring 2007 campaigns, respectively), but at lower detection frequency. The highest HBCD value was 62 ng/g lw. The similarity between profiles and seasonal variations in the concentrations of BFRs in soil and eggs indicate that soil is an important source, but not the sole source, for eggs laid by free-foraging chicken. The contamination of eggs with PBDEs and HBCD appears to be of low concern for public health and the contribution of eggs to the total daily intake of PBDEs appears to be limited (10% for chicken owners and 5% for the average Belgian consumer). 相似文献
22.
Claire Duménil David Woud Francesco Pinto Jeroen T. Alkema Ilse Jansen Anne M. Van Der Geest Sanne Roessingh Jean-Christophe Billeter 《Journal of chemical ecology》2016,42(3):259-269
Individuals can make choices based on information learned from others, a phenomenon called social learning. How observers differentiate between which individual they should or should not learn from is, however, poorly understood. Here, we showed that Drosophila melanogaster females can influence the choice of egg-laying site of other females through pheromonal marking. Mated females mark territories of high quality food by ejecting surplus male sperm containing the aggregation pheromone cis-11-vaccenyl acetate (cVA) and, in addition, deposit several sex- and species-specific cuticular hydrocarbon (CHC) pheromones. These pheromonal cues affect the choices of other females, which respond by preferentially laying eggs on the marked food. This system benefits both senders and responders, as communal egg laying increases offspring survival. Virgin females, however, do not elicit a change in the egg-laying decision of mated females, even when food has been supplemented with ejected sperm from mated females, thus indicating the necessity for additional cues. Genetic ablation of either a female’s CHC pheromones or those of their mate results in loss of ability of mated females to attract other females. We conclude that mated females use a pheromonal marking system, comprising cVA acquired from male ejaculate with sex- and species-specific CHCs produced by both mates, to indicate egg-laying sites. This system ensures information reliability because mated, but not virgin, females have both the ability to generate the pheromone blend that attracts other flies to those sites and a direct interest in egg-laying site quality. 相似文献
23.
This paper studies the stability of a class of PID controller to stabilize robot manipulators with elastic joints. It is shown that a PD action on the rotor position and an integral control action on the link position suffice to provide semiglobal asymptotic stability of the desired link position. 相似文献
24.
Eva Hopma Ashwin Ittoo Yuan Lu Ilse Luyk Laura Maruster Joël Ribeiro Ton Weijters Hans Wortmann 《Quality and Reliability Engineering International》2012,28(8):873-886
Advance technology development and wide use of the World Wide Web have made it possible for new product development organizations to access multi‐sources of data‐related customer complaints. However, the number of customer plaints of highly innovative consumer electronic products is still increasing; that is, product quality and reliability is at risk. This article aims to understand why existing solutions from literature as well as from industry to deal with these increasingly complex multiple data sources are not able to manage product quality and reliability. Three case studies in industry are discussed. On the basis of the case study results, this article also identifies a new research agenda that is needed to improve product quality and reliability under this circumstance. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
25.
Bogaerts Katleen; Van Eylen Lien; Li Wan; Bresseleers Johan; Van Diest Ilse; De Peuter Steven; Stans Linda; Decramer Marc; Van den Bergh Omer 《Canadian Metallurgical Quarterly》2010,119(1):226
The present study investigated differences in symptom perception between a clinical sample with medically unexplained symptoms (MUS) and a matched healthy control group. Participants (N = 58, 29 patients) were told that they would inhale different gas mixtures that might induce symptoms. Next, they went through 2 subsequent rebreathing trials consisting of a baseline (60 s room air breathing), a rebreathing phase (150 s, which gradually increased ventilation, PCO2 in the blood, and perceived dyspnea), and a recovery phase (150 s, returning to room air breathing). Breathing behavior was continuously monitored, and dyspnea was rated every 10 s. The within-subject correlations between dyspnea on the one hand and end-tidal CO2 and minute ventilation on the other were used to index the degree to which perceived dyspnea was related to specific relevant respiratory changes. The results showed that perceived symptoms were less strongly related to relevant physiological parameters in MUS patients than in healthy persons, specifically when afferent physiological input was relatively weak. This suggests a stronger role for top-down psychological processes in the symptom perception of patients with MUS. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
26.
27.
Occurrence,prevention and remediation of toxigenic fungi and mycotoxins in silage: a review 总被引:1,自引:0,他引:1 下载免费PDF全文
Eva Wambacq Ilse Vanhoutte Kris Audenaert Leen De Gelder Geert Haesaert 《Journal of the science of food and agriculture》2016,96(7):2284-2302
Ruminants are considered to be less sensitive towards mycotoxins than monogastric animals because rumen microbiota have mycotoxin‐detoxifying capacities. Therefore the effect of mycotoxins towards ruminants has been studied to a lesser extent compared with monogastric animals. Worldwide, a high proportion of the ruminant diet consists of silages made of forage crops (i.e. all parts of the crop above the stubble are harvested). In practice, silages are often contaminated with multiple mycotoxins. Exposure to a cocktail of mycotoxins can hamper animal production and have severe health consequences. In this article the different aspects associated with mycotoxin contamination of silage are reviewed ‘from seed to feed’. An overview is given on the occurrence of toxigenic fungal species and their concomitant mycotoxins in forage crops before and after ensiling. The mycotoxin load of visually non‐mouldy samples and mouldy hot spots within the same silo is also compared. Subsequently, this review delves into different problem‐solving strategies. A logical first step is prevention of mould growth and mycotoxin production in the field, during harvest and during ensiling. If prevention should fail, several remediation strategies are available. These are listed, mainly focusing on the possibilities of microbial degradation of mycotoxins in vivo in silage. © 2015 Society of Chemical Industry 相似文献
28.
Sun X Chen KJ Maddock-Carlin KR Anderson VL Lepper AN Schwartz CA Keller WL Ilse BR Magolski JD Berg EP 《Meat science》2012,92(4):386-393
The objective of this study was to investigate the usefulness of raw meat surface characteristics (texture) in predicting cooked beef tenderness. Color and multispectral texture features, including 4 different wavelengths and 217 image texture features, were extracted from 2 laboratory-based multispectral camera imaging systems. Steaks were segregated into tough and tender classification groups based on Warner-Bratzler shear force. The texture features were submitted to STEPWISE multiple regression and support vector machine (SVM) analyses to establish prediction models for beef tenderness. A subsample (80%) of tender or tough classified steaks were used to train models which were then validated on the remaining (20%) test steaks. For color images, the SVM model correctly identified tender steaks with 100% accurately while the STEPWISE equation identified 94.9% of the tender steaks correctly. For multispectral images, the SVM model predicted 91% and STEPWISE predicted 87% average accuracy of beef tender. 相似文献
29.
30.
K. Wisser Ilse Völter und W. Heimann 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1970,142(3):180-185
Zusammenfassung Unter Anwendung polarographischer Methoden wurde die Assoziation von schwefliger Säure und Dehydroascorbinsäure im Bereich von pH 3–5 untersucht. Es konnten in diesem Bereich die Dissoziationskonstanten und die Geschwindigkeitskonstanten von Assoziation und Dissoziation bestimmt Werden. Aus den ermittelten Daten geht hervor, daß derartige Messungen nur mit Hilfe der polarographischenRapid-Technik durchgeführt Werden können. Die Fehlerquellen bei titrimetrischen Bestimmungen von freier, neben gebundener schwefliger Säure werden diskutiert und quantitativ erfaßt.Von den widersprüchlichen Literaturangaben über das Dissoziationsverhalten der schwefligen säure konnte die vonJoslyn u.Braverman bestätigt werden.Einfache Versuche zeigen, daß Bräunung durch Produkte aus dem nichtoxydativen Abbau der Dehydroascorbinsäure bei Anwesenheit von schwefliger Säure nicht auftritt; eine Erklärung wird gegeben.
About the reaction of sulfurous acid during oxidation II. Binding of sulfurous acid with oxidation-products of ascorbic acid
Summary By using new polarographic methods, the association of sulfurous acid and dehydroascorbic acid Were studied in the range of pH 3–5. In this range it Was possible to determine the dissociation and the velocity constants of association and dissociation. From the results it is concluded that measurements of this kind only can be made by the polarographic rapid technique. The sources of error in using the titrimetric method are discussed and quantitatively determined.From the controversial results in the literature on the dissociation reaction of sulfurous acid, the findings ofJoslyn andBraverman could be confirmed.Simple results show that browning caused by products from non-oxidative decompostion of dehydroascorbic acid did not show up if sulfurous acid is present; an explanation for this is given.相似文献