Dietary intakes and food sources of fat and fatty acids in Guatemalan schoolchildren: A cross-sectional study

Background  

Consumption of healthy diets that contribute with adequate amounts of fat and fatty acids is needed for children. Among Guatemalan children, there is little information about fat intakes. Therefore, the present study sought to assess intakes of dietary fats and examine food sources of those fats in Guatemalan children.     

Hydroxytelechelic hydrocarbon copolymers with high aging resistance for elastomeric materials

Dihydroxytelechelic copolyalkenamers were prepared via metathetical polymerization of cyclic olefins (cyclooctadiene, cyclooctene and cyclododecene) in presence of first generation Grubbs catalyst and butene diacetate as functionalizing chain transfer agent in order to study their aging resistance. The influence of compositions and molar masses of the copolyalkenamers were investigated in terms of thermo‐mechanical properties. Increasing chains length or the proportion of polycyclooctadiene allow to get non‐cristalline polymers. Low T_g materials (between ?78°C and ?108°C) were prepared. The resistance towards oxidation of the different copolyalkenamers was carried out using a viscosity measurement method. A critical time, corresponding to a brutal increase of the apparent viscosity, was related to degradation of the polymers and was shown to be dependent on the Csp² proportion in the structure. The absence of vinylic units and the decrease of the double bonds content within the copolymers were proved to enhance the stability of the copolyalkenamers towards aging resistance. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

PCA3 and PCA3-Based Nomograms Improve Diagnostic Accuracy in Patients Undergoing First Prostate Biopsy

While now recognized as an aid to predict repeat prostate biopsy outcome, the urinary PCA3 (prostate cancer gene 3) test has also been recently advocated to predict initial biopsy results. The objective is to evaluate the performance of the PCA3 test in predicting results of initial prostate biopsies and to determine whether its incorporation into specific nomograms reinforces its diagnostic value. A prospective study included 601 consecutive patients addressed for initial prostate biopsy. The PCA3 test was performed before ≥12-core initial prostate biopsy, along with standard risk factor assessment. Diagnostic performance of the PCA3 test was evaluated. The three available nomograms (Hansen’s and Chun’s nomograms, as well as the updated Prostate Cancer Prevention Trial risk calculator; PCPT) were applied to the cohort, and their predictive accuracies were assessed in terms of biopsy outcome: the presence of any prostate cancer (PCa) and high-grade prostate cancer (HGPCa). The PCA3 score provided significant predictive accuracy. While the PCPT risk calculator appeared less accurate; both Chun’s and Hansen’s nomograms provided good calibration and high net benefit on decision curve analyses. When applying nomogram-derived PCa probability thresholds ≤30%, ≤6% of HGPCa would have been missed, while avoiding up to 48% of unnecessary biopsies. The urinary PCA3 test and PCA3-incorporating nomograms can be considered as reliable tools to aid in the initial biopsy decision.     

Polymer stain resistance: Prediction versus experiment

The coloration of different polymer films (from commodity and packaging films to performance films) by contact with various food coloring substances was evaluated. For this purpose, both solubility parameters as a prediction tool, and immersion experiments for time range between 24 and 1000 h were established. The two predicting tools are the Hoy and Hoftyzer‐Van Krevelen (HVK) methods. For PE and PP, HVK's method is preferred for predicting coloration. Neither of the HVK's and Hoy's methods was able to establish a coloration prediction for PET while both methods could predict the staining of PEEK. The coloration of partially and fully fluorinated polymers is well predicted by the Hoy's method. The behavior of PP/PA and PP/PA/PP multilayer films was also studied. Crystallinity degree of polymers, temperature and concentration of coloring molecules are also important parameters, which are not taken into account in solubility theories. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis,structure, and characterization of the thorium zirconolite CaZr1-xThxTi2O7 system

A series of zirconolite ceramics with composition CaZr_1-xTh_xTi₂O₇ (Δx = 0.10) were reactively sintered at 1350°C for 20 h, in air (0 ≤ x ≤ 0.60) and 5% H₂/N₂ (0 ≤ x ≤ 0.40). A sample with composition corresponding to x = 0.20 was also produced by hot isostatic pressing (HIP) at 1300°C and 100 MPa for 4 hours. Th⁴⁺ immobilization was most readily achieved under oxidizing conditions, with Th⁴⁺ preferentially incorporated within a pyrochlore-structured phase in the range 0.10 ≤ x ≤ 0.50, yet formation of the zirconolite-4M polytype was not observed. We report the novel synthesis of single-phase pyrochlore with nominal composition CaZr_0.40Th_0.60Ti₂O₇ when targeting x = 0.60. Th⁴⁺ incorporation under reducing conditions produced a secondary Th-bearing perovskite, comprising 24.2 ± 0.6 wt% of the phase assemblage when targeting x = 0.40, alongside 8.8 ± 0.3 wt% undigested ThO₂. Under reducing conditions, powder XRD data were consistent with zirconolite adopting the 3T polytype structure. The sample produced by HIP presented a nonequilibrium phase assemblage, yielding a major phase of zirconolite-2M alongside accessory Th⁴⁺-bearing phases ThTi₂O₆, ThO₂, and perovskite. These data highlight the efficacy of Th⁴⁺ as a Pu⁴⁺ surrogate, with implications for the formation of Zr-stabilized Th-pyrochlore phases as matrices for waste with elevated Th⁴⁺ content.     

Ecosystem matters: fish consumption, mercury intake and exposure among fluvial lake fish-eaters

Many studies use the number of fish meals as an estimate of Hg intake, although fish Hg concentrations, even within the same species, can greatly vary. Furthermore, most freshwater advisories only refer to local catch, while market fish advisories only focus on market fish, although both can contribute to Hg body burden. The present study, carried out in lakeside communities from 2 ecosystems in Quebec, Canada, sought to (i) estimate Hg intake from local freshwater sources, hunted waterfowl and market fish and seafood, and (ii) examine the relations between fish consumption, estimated Hg intake and biomarkers of exposure. A total of 238 adults (18-74 years), who had consumed local catch within the past three months, responded to an extensive interview-administered fish and waterfowl frequency questionnaire. Anthropometric measures were taken and a self-administered questionnaire was used to obtain socio-demographic information. Hg intake was estimated as µg Hg/kg body weight/day. Blood and hair samples were analyzed for Hg content. Results showed that persons from one ecosystem ate significantly more fish compared to those from the other (median: 52.1 g/day vs 38.9 g/day), but presented significantly lower concentrations of hair Hg (median: 448.0 ng/g vs 730.5 ng/g), blood organic Hg (median: 1.1 µg/L vs 3.4 µg/L) and inorganic Hg (median: 0.4 µg/L vs 0.8 µg/L). Median daily total Hg intake was 0.080 µg/kg bw/day for the former community and 0.141 µg/kg bw/day for the latter. Overall, 59.5% from the first ecosystem and 41.0% from the other, exceeded the US EPA RfD (0.1 µg/kg bw/day), while 13.2% and 6.0%, respectively, exceeded the Canadian tolerable daily intake (0.47 µg/kg bw/day) for adults. For the two groups, freshwater fish consumption frequency, but not total fish, was positively associated with bioindicators of Hg while estimated Hg intake from freshwater catch as well as from total fish consumption were positively related to Hg biomarkers. There was a positive relation between consumption and estimated Hg intake from freshwater fish and blood inorganic Hg. These findings indicate that the number of fish can be a poor surrogate for Hg exposure. The differences observed here for Hg intake and exposure reflect ecosystem disparities in fish diversity and Hg bioaccumulation. Studies and advisories need to consider Hg fish concentrations and fish-eating patterns in different ecosystems, as well as the contribution of market fish. The relation between fish consumption and inorganic Hg exposure, reported as well in other studies, needs to be further investigated.     

Moisture barrier and physical properties of acetylated derivatives with increasing acetylation degree

Four acetostearin products with increasing acetylation degree were synthesized by chemical interesterification followed by fractionation/blending stages. Their physical properties and functional barrier properties were studied and compared to the properties of technical tristearin. Increasing acetylation degree (AD) modified the triacylglycerols crystal habits and probably led to an increase in acyl chain fluidity, which induced, at macroscopic levels, a decrease in solid fat content (SFC), in melting point, in surface and bulk material hydrophobicity, and an increased moisture effective diffusivity. Water vapor permeability (WVP) coefficients of the materials were partially influenced by the AD factor, but also by the development of macroscopic cracks in lipids presenting high SFC. Acetylated stearin up to 47% (acetyl mol/mol of esterified chain) presented the lowest WVP at 20 °C resulting from an adequate balance between hydrophobicity and mechanical properties of the material.