Mechanical,thermal, and flame-retardant performance of polyamide 11–halloysite nanotube nanocomposites

This study focused on the influence of different filler loadings on the elongation at break and flammability properties of the PA11/FR/HNTs nanocomposites. Polyamide 11 (PA11)/flame-retardant (FR) additives/halloysite nanotubes (HNTs) nanocomposites were melt compounded via twin-screw extrusion for all the compositions. Three FR additive loadings (15, 20, and 25 wt%) and three HNTs loadings (2.5, 5, and 10 wt%) were selected. The formula with 25 % FR and 2.5 % HNT had the lowest additives content and the highest elongation at break of 10.22 % among all UL-94 V-0 rated formulas. A homogeneous dispersion of HNTs in PA11 matrix was observed by transmission electron microscopy. Differential scanning calorimeter measurements indicated that HNTs behaved as nucleating agents by accelerating the rate of crystallization, thus increasing crystallization temperature. The young’s modulus of the PA11 nanocomposites was enhanced with the addition of HNTs. Micro-scale combustion calorimeter results demonstrated that the addition of HNTs also decreased the peak heat release rate of the nanocomposites. These results indicate the effectiveness of HNTs on the mechanical, thermal, and flame-retardant performance of PA11/FR/HNTs nanocomposites.     

Interaction of silver nanoparticles with an environmentally beneficial bacterium, Pseudomonas chlororaphis

This study explores the potential antimicrobial mechanisms of commercial silver nanoparticles (Ag NPs) in the environmental bacterium, Pseudomonas chlororaphis O6. The 10nm size NPs aggregated in water, as demonstrated by atomic force microscopy. Solubility of the NPs at 10mg/L was 0.28 mg/L (pH 6) and 2.3mg/L (pH 7); release from 10mg/L bulk Ag was below detection. The NPs eliminated cell culturability at 3mg/L, whereas no effect was observed at 10mg/L bulk Ag. Zeta potential measurements revealed that the NPs were negatively charged; unlike Ag ions, their addition to the negatively charged cells did not change cell charge at pH 6, but showed a trend to reduce cell charge at pH 7. Isolated extracellular polymeric substances (EPS) from PcO6 was polydisperse, with negative charge that was neutralized by Ag ions, but not by the NPs. Addition of EPS eliminated Ag NP's toxicity in cells lacking EPS. Intracellular accumulation of OH was not detected in NP-treated cells; however, the use of scavengers suggested the NPs caused extracellular H(2)O(2) production. No evidence was found for loss of membrane integrity upon treatment with the NPs. Our findings indicate that growth of environmental bacteria could be impaired by Ag NPs, depending on the extent of EPS production.     

Sweet temptation: Effects of exposure to chocolate-scented lotion on food intake

Food-scented products are widely available, yet it is unclear whether they influence eating behavior. Food-related cues can increase intake; therefore, it was anticipated that conscious exposure to food-scented products (e.g., body lotion) could also influence consumption. Female participants (n = 58) were randomly assigned to an exposure condition (labeled chocolate lotion, unlabeled chocolate lotion, or unscented lotion), and their subsequent intake of chocolate-chip cookies was measured. A significant effect of condition on intake emerged. Those who knew that they were evaluating a chocolate-scented lotion ate more than did those exposed to the same (unlabeled) lotion, suggesting that conscious exposure to chocolate-related products may increase food intake.     

Influence of steaming treatment on chemical and technological characteristics of einkorn (Triticum monococcum L. ssp. monococcum) wholemeal flour

Einkorn (Triticum monococcum ssp. monococcum) is an underutilised wheat with high protein, lutein and tocols content, particularly suited for baby and specialty foods. To study the influence of kernel steaming treatments on chemical and technological properties, seeds of five einkorn accessions and one bread wheat control (cv. Blasco) underwent different steaming conditions, and their wholemeal flours were compared for ash, protein, lutein, tocols and α-amylase content, SDS sedimentation volume and gelatinisation parameters. Furosine, a heat damage marker, was measured as well. The treatments significantly influenced most of the parameters. In particular, lutein, tocols and α-amylase diminished after steaming; SDS sedimentation volumes and most gelatinisation parameters also decreased, whereas gelatinisation temperatures and furosine contents increased. The changes were stronger under more drastic steaming conditions, although treatment × genotype influence was sometimes detected. Steaming induced migration of lutein and tocopherols from the bran and germ fractions to the kernel endosperm.     

绿色经营不只是负担

通过将人、环保和利润统一起来,企业可以将可持续发展战略转变为竞争优势。车库中的混合动力汽车,食品储藏室内的咖啡豆,精确管理的恒温器,打印机中重复利用的墨盒。     

Trauma exposure, mental health, and service utilization rates among immigrant and United States-born Hispanic youth: Results from the Hispanic family study.

Although the largest immigrant group in the United States is Hispanic, little is known about their rates of traumatic experiences and psychiatric disorders, particularly for youth. Findings with adults suggest that recent immigrants have lower rates of mental illness than long-time residents or U.S.-born Hispanics, but use health-related services less often. The present study examined this relationship in a convenience sample of 131 foreign-born (64.5%) and 72 U.S.-born (35.5%) Hispanic youth, ages 8–17 years and a subset of their caregivers (n = 110). Findings from youth interview data suggest that immigrant and U.S.-born youth did not differ significantly in experiences of potentially traumatizing events or psychiatric disorders. However, findings from caregiver interview data suggest that there were significant disparities between the two groups in health service utilization for doctors and other medical professionals, with caregivers reporting that foreign-born youth utilize these health services at lower rates than U.S.-born youth. Results are discussed in the context of prior findings and recommendations offered for increasing service utilization. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attending to others’ posts in asynchronous discussions: Learners’ online “listening” and its relationship to speaking

Theoretical models of collaborative learning through online discussions presuppose that students generally attend to others’ posts. However, a succession of studies over the last decade has shown this assumption to be unwarranted. Instead, research indicates that learners attend to others’ posts in diverse and particular ways—an activity we have conceptualized as online “listening.” In this study, we take an important step forward in developing a robust theory of online listening by examining the relationship between how learners “listen” (access existing posts) and “speak” (contribute posts) in online discussions. Ten variables indexing four dimensions of students’ listening (breadth, depth, temporal contiguity and revisitation) and five variables indexing three dimensions of students’ speaking (discursiveness, depth of content and reflectivity) were calculated for 31 students participating in 6 week-long online discussions as part of an undergraduate educational psychology course. Multi-level mixed-model linear regressions indicated that responsiveness of students’ posts was positively predicted by how often they revisited previously read peer posts, and negatively related to a greater number of posts in the discussion overall. The depth of posts’ contents was predicted by the percentage of posts viewed that students actually read (as opposed to scanned). An exploratory follow-up analysis indicated that these listening-speaking relationships manifest differently over time for distinct subsets of learners (e.g., a decrease in variable pairs versus corresponding fluctuations around stable levels). Put together, results suggest that when students take the time to read and re-read their peers’ posts there are related benefits in the quality of the posts they contribute.