Application of MALDI-TOFMS Combined with Partial Least Square Regression for the Determination of Mercury and Copper in Canned Tuna,Using Dithizone as the Complexing Agent and Ag(I) as Internal Standard

In this work, a procedure for the determination of mercury and copper in canned tuna samples is presented, based on the extraction of their respective dithizone complexes and quantification by conventional MALDI-TOFMS with the aid of partial least square regression (PLS2). Methanolic dithizone solution (1 ml, 0.01% m/v) containing Ag(I) as internal standard was added to the calibration solutions and to the acid-digested samples (5 ml, pH 3); copper, mercury, and silver complexes were extracted to cyclohexane (1.5 ml), and after evaporation, the residues were re-constituted in acetone (100 μl). The samples were prepared by dried droplet crystallization with α-cyano-4-hydroxycinnamic acid. The experimental and MALDI-TOFMS instrument operating conditions were set up under criteria of as high as possible detectability and repeatability. When univariate calibration was carried out using the most intense ion of Cu or Hg complex normalized by internal standard, determination seemed feasible yet precision of the results was poor. Taking baseline-corrected spectra in m/z range 560–725, PLS2 model was constructed for the prediction of two elements with the method quantification limits 63 μg kg^?1 for Cu and 75 μg kg^?1 for Hg, respectively. For different brands of canned tuna, the results obtained by MALDI-TOFMS combined with PLS2 and by ICP-MS were in good agreement. The proposed procedure is an attractive alternative for the determination of trace metals in foods because of the procedural simplicity, micro-scale dimension, high speed of data acquisition/processing, and the cost of instrument operation lower as compared to any atomic spectrometry technique.     

New efficient cross‐layer and multihoming mechanisms at layer 2 for inter‐radio access technology handover between UMTS and WiMAX

Next generation mobile networks will provide seamless mobility between existing cellular systems and other wireless access technologies. To realize a seamless vertical handover (inter‐radio access technology handover) among these different access technologies, a multi‐interfaced mobile station (i.e., multihomed) is a good approach to provide better handover performance in terms of packet loss rate and handover latency. In this article, we propose a novel layer 2 multihoming approach for inter‐radio access technology handover between Universal Mobile Telecommunications System (UMTS) and Worldwide Interoperability for Microwave Access (WiMAX) in both integrated and tight coupling architectures. This layer 2 multihoming approach has the ability of enabling either soft handover or make‐before‐break handover to adapt to mobility scenarios for the sake of a lossless and short latency handover procedure. Our simulation results show that, in case of handover from UMTS to WiMAX for transmission control protocol (TCP) traffics, the layer 2 multihoming approach can achieve a lossless and zero latency handover procedure by enabling soft handover. In case of handover from WiMAX to UMTS, because of the fact that the performance gain of soft handover is more affected by the differences of bandwidth and transmission delay between these wireless links, the make‐before‐break handover is preferred to achieve lossless and short latency handover procedure. Copyright © 2012 John Wiley & Sons, Ltd.     

The effectiveness of published continuum constitutive laws to predict stress-assisted densification of powder compacts

Commonly used constitutive laws for crystalline and viscous materials have been compared to predict the densification behavior under hot-pressing and sinter-forging. Experimental results, from literature for one loading condition, have been used to extract the constitutive laws for amorphous and crystalline materials and, these in-turn, have been used to predict behavior under a different set of loading conditions. Ideally, the constitutive parameters obtained from one set of loading conditions and thermal history should apply to a different set of conditions. However, there is a lack of systematic experimental studies in which this can be checked. In this paper, we use constitutive parameters obtained from one set of conditions to predict the densification response under a different set of loading conditions. For both sintering of amorphous and crystalline materials, we use two different constitutive parameters and compare the predictions of these for the case where experimental results are not available. In addition, the effect of temperature on densification behavior for stress-assisted sintering has been investigated. It is shown that the two commonly used constitutive models for viscous sintering (Scherer and Skorohod–Olevsky) predict similar behavior for amorphous materials. However, for crystalline materials, the predictions of the Riedel–Svoboda and the Kuhn–Sofronis–McMeeking (KSM) models are different. Finally, it is shown that the dependence of the normalized densification on temperature, under constant heating rate conditions, with parameters obtained from isothermal experiments, is a good test for the models.     

The sensitivity of radiation-induced leakage to STI topology and sidewall doping

The sensitivity of radiation-induced source-drain leakage to the amount of recess in the shallow-trench isolation (STI) of CMOS technologies is reported. The impact of the doping profile along the STI sidewall on the magnitude of the leakage current is quantified. The sensitivity of the radiation-induced leakage current to these parameters provides insight into how process variability is manifested as variations in the radiation response.     

Drinking outcomes following drink refusal skills training: Differential effects for African American and non-Hispanic White clients.

Determining whether a particular treatment works for specific groups of people can help tailor dissemination of evidence-based alcohol treatments. It has been proposed that individuals from different racial groups might have better outcomes in treatments that are sensitive to sociocultural issues that impact alcohol use among these groups. The current study was a secondary analysis of data from the combined behavioral intervention (CBI) condition of the COMBINE study. Those randomly assigned to CBI (n = 776) had the opportunity to receive up to 9 skills training modules, which were chosen by the therapist. The goal of the current study was to determine whether receiving 1 of the CBI modules, drink refusal and social pressure skills training, predicted differential outcomes among African American clients. Results indicated that African American clients who received the drink refusal skills training module (n = 25) had significantly fewer heavy drinking days (d = 0.79) 1 year following treatment than African Americans clients who did not receive the module (n = 35). African American clients who received the module also had significantly fewer heavy drinking days (d = 0.86) than non-Hispanic White clients who received the module (n = 241). Good clinical outcomes at 1 year posttreatment were observed among 80% of African Americans who received the module, compared with 54% of African Americans who did not receive the module and 52% of non-Hispanic White clients who did receive the module. Although small sample size limits interpretation, findings provide preliminary evidence supporting the inclusion of drink refusal skills training as part of alcohol interventions for African American clients. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

A dynamic model to calculate cadmium concentrations in bovine tissues from basic soil characteristics

A chain model was developed to calculate the flow of cadmium from soil, drinking water and feed towards bovine tissues. The data used for model development were tissue Cd concentrations of 57 bovines and Cd concentrations in soil, feed and drinking water, sampled at the farms were the bovines were reared. Validation of the model occurred with a second set of measured tissue Cd concentrations of 93 bovines of which age and farm location were known. The exposure part of the chain model consists of two parts: (1) a soil-plant transfer model, deriving cadmium concentrations in feed from basic soil characteristics (pH and organic matter content) and soil Cd concentrations, and (2) bovine intake calculations, based on typical feed and water consumption patterns for cattle and Cd concentrations in feed and drinking water. The output of the exposure model is an animal-specific average daily Cd intake, which is then taken forward to a kinetic uptake model in which time-dependent Cd concentrations in bovine tissues are calculated. The chain model was able to account for 65%, 42% and 32% of the variation in observed kidney, liver and meat Cd concentrations in the validation study.     

Yoghurt consumption regulates the immune cells implicated in acute intestinal inflammation and prevents the recurrence of the inflammatory process in a mouse model

Crohn's disease and ulcerative colitis, two forms of inflammatory bowel disease, are important problems in industrialized countries. The complete etiology of these two diseases is still unknown but likely involves genetic, environmental, and immunological factors. The aim of the present work was to determine whether the anti-inflammatory effects reported for yoghurt in acute trinitrobenzene sulfonic acid-induced intestinal inflammation in mice also could prevent or attenuate the recurrent intestinal inflammation, thus maintaining remission. The innate response also was evaluated through participation of Toll-like receptors (TLRs) and the analysis of T-cell populations to determine the effects of yoghurt in an acute inflammatory bowel disease model. Yoghurt exerted a beneficial effect on acute intestinal inflammation by regulating T-cell expansion and modulating the expression of TLRs, with decrease of TLR4(+) and increase of TLR9(+) cells. The anti-inflammatory effect of yoghurt also was demonstrated in a recurrent inflammation model. Yoghurt administration during the remission phase prevented the recurrence of inflammation without producing undesirable side effects. The yoghurt effect may be mediated by increased interleukin 10 production and changes in intestinal microbiota.     

Moisture-induced caking of beverage powders

BACKGROUND: Beverage powders can exhibit caking during storage due to high temperature and moisture conditions, leading to consumer dissatisfaction. Caking problems can be aggravated by the presence of sensitive ingredients. The caking behaviour of cocoa beverage powders, with varying amounts of a carbohydrate sensitive ingredient, as affected by climate conditions was studied in this work. Sorption isotherms of beverage powders were determined at water activities (a_w) ranging from 0.1 to 0.6 in a moisture sorption analyser by gravimetry and fitted to the Brunauer–Emmett–Teller (BET) or the Guggenheim–Anderson–de Boer (GAB) equation. Glass transition temperatures (T_g) at several a_w were analysed by differential scanning calorimetry and fitted to the Gordon–Taylor equation. Deduced T_g = f(a_w) functions helped to identify stability or caking zones. Specific experimental methods, based on the analysis of mechanical properties of powder cakes formed under compression, were used to quantify the degree of caking. Pantry tests complemented this study to put in evidence the visual perception of powder caking with increasing a_w. RESULTS: The glass transition approach was useful to predict the risks of caking but was limited to products where T_g can be measured. On the other hand, quantification of the caking degree by analysis of mechanical properties allowed estimation of the extent of degradation for each product. CONCLUSION: This work demonstrated that increasing amounts of a carbohydrate sensitive ingredient in cocoa beverages negatively affected their storage stability. Copyright © 2011 Society of Chemical Industry