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921.
Recently, organic and inorganic chlorinated compounds were detected in crude and commercially refined palm oils. Further, the predominant formation mechanism of monochloropropanediol (MCPD) diesters at high temperatures (>170-180°C) was revealed. The present study involved the development and comparison of solutions to mitigate MCPD diester levels in oils from various stages of palm oil production. Partially refined palm oil samples and oil extracted from fresh palm fruits were submitted to bench-top deodorisation experiments. Application of glycerol and ethanol as refining aids during the deodorisation of refined-bleached palm oil proved to be moderately effective; about 25%-35% reduction of MCPD diester levels was achieved. Washing crude palm oil with ethanol-water (1:1) prior to deodorisation was also an effective strategy yielding an ~30% reduction of MCPD diester contents. Washing palm fruit pulp before oil extraction, however, was most impactful, resulting in a 95% reduction of MCPD diesters when compared to the deodorised control oil. This suggests that intervention upstream in the process chain is most efficient in reducing levels of these contaminants in refined oils. Following the study, a root-cause analysis was performed in order to map the parameters potentially responsible for the occurrence of MCPD diesters in refined palm oil and related fractions.  相似文献   
922.
Biodegradable coatings based on 1% and 2% sodium alginate (NaAlg) with and without grapefruit seed extract (GSE) or grapefruit essential oil (GEO) were applied to table grapes to preserve their quality. Changes in weight loss, firmness and antioxidant activity were assessed over 15 days of cold storage. The effectiveness of developed coatings to control postharvest decay of inoculated grape berries stored for 5 days at 20 °C was also investigated. Biodegradable coatings based on pure NaAlg and those containing GSE were efficient in reducing weight loss and maintaining firmness during storage. Coatings incorporating either GEO or GSE were able to preserve the antioxidant activity of treated grapes and to reduce decay incidence in inoculated fruits. Coatings formulated with 2% NaAlg‐1% GSE showed the greatest preservation of antioxidant activity and the highest antifungal effect, with an effective control of water and firmness losses. These coatings can be recommended for maintaining table grapes quality.  相似文献   
923.
Reverse phase HPLC has been applied to quantify levels of polymethoxylated flavones and carotenoids in orange and tangelo juices. Lower levels of sinensetin and tetramethyl‐o‐scutellarein and higher levels of heptamethoxyflavone and tangeretin relative to nobiletin indicated the addition of tangelo to orange juice. β‐Cryptoxanthin and its esters, identified by positive ion electrospray mass spectrometry, were present in larger amounts relative to β‐carotene in tangelo than in orange juice. Using canonical discriminant analysis, the addition of 100 g kg?1 tangelo to orange juice can be detected. © 2002 Society of Chemical Industry  相似文献   
924.
Investigated the concurrent and predictive validity of the Self-Disclosure Questionnaire (SDQ) as a measure of counselor effectiveness by examining its relationship to measures of empathy and self-disclosure. 49 students enrolled in a techniques of counseling class served as Ss. Scores on the SDQ and rated scores of actual self-disclosure obtained from a training exercise were collected prior to the beginning of the training program. Pre- and posttraining scores were obtained on 2 measures of empathy: Affective Sensitivity Scale and Empathic Understanding in Interpersonal Processes. Overall, results fail to support both the concurrent and the predictive validity of the SDQ. Absence of predictive validity, however, was not due to lack of gain in skills as scores on both empathy measures increased significantly as a result of training. It was noted, however, that the behavioral measure of actual self-disclosure employed was highly correlated with 1 of the empathy measures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
925.
Reproductive performance in pasture-based production systems has a fundamentally important effect on economic efficiency. The individual factors affecting the probability of submission and conception are multifaceted and have been extensively researched. The present study analyzed some of these factors in relation to service-level probability of conception in seasonal-calving pasture-based dairy cows to develop a predictive model of conception. Data relating to 2,966 services from 737 cows on 2 research farms were used for model development and data from 9 commercial dairy farms were used for model testing, comprising 4,212 services from 1,471 cows. The data spanned a 15-yr period and originated from seasonal-calving pasture-based dairy herds in Ireland. The calving season for the study herds extended from January to June, with peak calving in February and March. A base mixed-effects logistic regression model was created using a stepwise model-building strategy and incorporated parity, days in milk, interservice interval, calving difficulty, and predicted transmitting abilities for calving interval and milk production traits. To attempt to further improve the predictive capability of the model, the addition of effects that were not statistically significant was considered, resulting in a final model composed of the base model with the inclusion of BCS at service. The models' predictions were evaluated using discrimination to measure their ability to correctly classify positive and negative cases. Precision, recall, F-score, and area under the receiver operating characteristic curve (AUC) were calculated. Calibration tests measured the accuracy of the predicted probabilities. These included tests of overall goodness-of-fit, bias, and calibration error. Both models performed better than using the population average probability of conception. Neither of the models showed high levels of discrimination (base model AUC 0.61, final model AUC 0.62), possibly because of the narrow central range of conception rates in the study herds. The final model was found to reliably predict the probability of conception without bias when evaluated against the full external data set, with a mean absolute calibration error of 2.4%. The chosen model could be used to support a farmer's decision-making and in stochastic simulation of fertility in seasonal-calving pasture-based dairy cows.  相似文献   
926.
The effect of the Mycobacterium avium ssp. paratuberculosis (MAP) ELISA status on test-day milk performance of cows from Irish herds enrolled in the pilot national voluntary Johne's disease control program during 2013 to 2015 was estimated. A data set comprising 92,854 cows and 592,623 complete test-day records distributed across 1,700 herds was used in this study. The resulting ELISA outcome (negative, inconclusive, and positive) of each cow within each year of the program was used to allocate the cow into different scenarios representing the MAP status. At MAPscenario1, all cows testing ELISA nonnegative (i.e., inconclusive and positive) were assigned a MAP-positive status; at MAPscenario2 only cows testing ELISA-positive were assigned a MAP-positive status; at MAPscenario3 only cows testing ELISA nonnegative (inconclusive or positive) and gathered exclusively from herds where at least 2 further ELISA nonnegative (inconclusive or positive) cows were found were assigned a MAP-positive status; at MAPscenario4 only cows testing ELISA-positive that were gathered exclusively from herds where at least 2 further ELISA-positive cows were found were assigned a MAP-positive status. Milk outputs based on test-day records were standardized for fat and protein contents (SMY) and the effect of MAP ELISA status on the SMY was estimated by a linear mixed effects model structure. The SMY mean difference recorded at test day between cows with a MAP-positive status and those with a MAP-negative status within MAPscenario1 was estimated at ?0.182 kg/test day; the mean difference was ?0.297 kg/test day for MAPscenario2; for MAPscenario3 mean difference between MAP-positive status and MAP test-negative cows was ?0.209 kg/test day, and for MAPscenario4, the difference was ?0.326 kg/test day.  相似文献   
927.
Summary Chocolates, boiled sweets, toffees, cakes and meat pies were wrapped in regenerated cellulose films (with or without coatings) that contained various mixtures of glycol softeners and which had been specially formulated for particular food applications. Samples were unwrapped at intervals (up to the end of the usual maximum shelf-life for the food) and analysed for their glycol content. Analysis involved homogenization of the food in hot water, removal of fats with hexane, precipitation of sugars with calcium hydroxide and analysis of the glycols by capillary gas chromatography with flame ionization detection (GC/ FID) after trimethylsilyl (TMS) derivatization. Triethylene glycol was analysed by selected ion monitoring GC/mass spectrometry (GC/MS) as interference problems occurred with the GC/FID approach. The results of the study showed that higher levels of migration occurred for propylene glycol than for triethylene glycol and the presence of a coating reduced the migration of both softeners. Generally, mono- and diethylene glycol levels in the food samples were below 10 mg/kg, although some samples wrapped in polyethylene glycol-softened films contained levels approaching the current statutory limit of 50 mg/kg.
Die Wanderung von Propylenglykol, Mono-, Di-, und Triethylenglykol aus regenerierter Cellulosenfolie in Lebensmitteln
Zusammenfassung Pralinen, Fruchtbonbons, Caramelbonbons, Kuchen und Fleischpasteten wurden in Folien aus Regeneratcellulose (sowohl mit als auch ohne Beschichtung) verpackt, die verschiedene Mischungen von Glykolweichmachern enthielten und speziell für ihre Eignung bei besonderen Lebensmittelanwendungen hergestellt wurden. Nach Ablauf der normalen bzw. maximalen Haltbarkeitszeit der Lebensmittel und ebenso bei einigen dazwischenliegenden Zeitpunkten wurden die Proben ausgepackt und auf ihre Glykolkontamination überprüft. Die Analyse umfaßte die Homogenisierung der Lebensmittel in heißem Wasser, die Abtrennung von Fetten mittels Hexan, die Fällung der Zucker unter Verwendung von Calciumhydroxid und die Analyse der Glykole durch Capillar-Gaschromatographie mit Flammen-Ionisations-Detektion (GC/FID) nach der Trimethylsilyl(TMS)-Derivatisierung. Die Bestimmung von Triethylenglykol erfolgte mittels selektiver Ionenregistrierung-GC/Massenspektrometrie (GC/MS), da sich bei der GD/FID-Methode Probleme der Interferenz ergaben. Die Versuchsergebnisse zeigten bei Propylenglykol einen höheren Wanderungsgrad als bei Triethylenglykol, wobei das Vorhandensein einer Beschichtung in beiden Fällen die Wanderung der Weichmacher reduzierte. Mono- und Diethylenglykolgehalte der Lebensmittel waren im allgemeinen unter 10 mg/kg, jedoch enthielten manche Proben, die in Folien mit Polyethylenglykolweichmachern verpackt wurden, eine Glykolmenge die sich der zur Zeit vorgeschriebenen Höchstgrenze von 50 mg/kg nähert.
  相似文献   
928.
Low molecular weight additive effects on the mid-kilohertz mobility of atactic polystyrene (PS) at 25°C via n.m.r. spin-lattice relaxation experiments in the rotating frame (T1?) are analogous to the results of a previous study of diluents in glassy bisphenol-A polycarbonate. The diluent with a relatively low glass transition temperature (Tg), dioctylphthalate, increases the spectral density of thermal motions of the chain backbone and the pendant group in PS on the order of 38.5 kHz. Of the 13C nuclei in the glassy polymer, the relaxation behaviour of which can be differentiated by high-resolution, solid-state n.m.r., the T1?'s of the aromatic carbons in the side group are affected most by dioctylphthalate. In contrast, the styrene oligomer, which has a higher Tg than that of dioctylphthalate, does not significantly alter the ambient temperature mobility of polystyrene at 38.5 kHz. The PS-styrene oligomer and PS-dioctylphthalate blends are examples of athermal and non-athermal mixtures, respectively. However, the effect of the enthalpy of mixing on the T1?'s of the polymer is probably obscured by differences in blend mobility due to different blend Tg's.  相似文献   
929.
    
Nacre-inspired brick-and-Mortar composite structures exhibit exceptional combinations of properties as well as a highly tuneable mechanical response, due to their large range of design parameters. Understanding the effect of these parameters on the response is essential to optimally design these structures and can be guided by modeling. Traditional models only consider 2D geometries and limited attempts at modeling 3D geometric designs exist. Herein, 3D brick-and-mortar structures using a finite element in conjunction with an experimentally calibrated cohesive zone model to represent the layers are proposed. The model is successfully validated against experimental results for a nonplanar brick assembly using so-called osteomorphic bricks. The capabilities of the model are further demonstrated through a parametric study, where the effect of brick shape, number of bricks, and soft layer material properties on the structure mechanical properties (elastic modulus, yield strength and toughness) are investigated. Numerical results show that toughness is significantly increased by transitioning from a “two-peak” failure mechanism to a “peak-plateau-peak,” which is controlled by the brick shape. It is also shown that 3D structures may exhibit significant out-of-plane deformation involving the cooperative motion of many bricks, which may contribute to their improved toughness compared to 2D structures.  相似文献   
930.
    
The Alcazar Palace (Seville, Spain) is famous for its ceramic decorations; 16th century wall tiles of different typologies have been analyzed in order to relate the manufacturing process of their colored glazes to the evolving technologies of the Renaissance. Chemical and mineralogical compositions have been determined in situ by nondestructive X-ray fluorescence and X-ray diffraction on arista ceramics in the Cenador de Carlos Quinto, and majolica ceramics in the Palacio Gotico and the Royal oratory. The arista style belongs to the local Hispano-Moresque ceramic tradition. Majolica tiles have the complex microstructures of glazes from Italy. The two types are clearly differentiated by their typology, morphology (curved vs flat surface), and also microstructure (single vs multi-layers), glaze chemistry, and use of different coloring agents. Moreover, we found different glaze chemistries in the investigated majolicas, which correspond to different artists and/or practices.  相似文献   
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