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Ultrathin films (12−125 nm) of poly(L-lactide)/poly(D-lactide) (PLLA/PDLA) blends of different compositions have been crystallized between 180 and 210 °C, i.e., above the melting point of each polymer crystallized separately. The overall crystal shape depends on the temperature, film thickness and ratio of the two polyenantiomers in the blends. In nonequimolar blends, lamellae show curvatures, and the sense of the curvature is determined by the chirality of the polyenantiomer in excess, blend ratio, film thickness, crystallization temperature and lamellar orientation (flat-on or edge-on). The curvature of the stereocomplex lamellae is ascribed to the unequal amount of PLLA and PDLA segments at the crystal growth front, creating an unbalanced mechanical stress at the chain folding surfaces which can be released by a curvature of the growth tip.

"Recent volatility in food prices and the growing disparity between prices at various stages of the marketing channel has generated much interest among agricultural producers, consumers, and policy makers. This study examines the effect of nonlinear threshold dynamics on asymmetric price transmission for three U.S. dairy products (butter, cheese, and fluid milk) using threshold error correction models. The empirical result suggests that price transmission of changes between producer and retail stages of the marketing chain is asymmetric for butter and fluid milk, but not for cheese prices. Also, this paper's findings indicate that conclusions about price asymmetries depend on the model specification assumptions made about symmetry and threshold effects. Thus, previous studies that assumed symmetric behavior and ignored threshold effects may be misleading." Copyright (c) 2009 Canadian Agricultural Economics Society.

The ATC/DDD methodology proved useful for studying overall antibiotic usage in children's hospitals. The decline in antibiotic usage found in 2006 (and the reduced variation between hospitals) may be attributed to the impact of the Ministry of Health guidelines which took some time to be promulgated to individual staff members. Further research will focus on compliance of antibiotic use in these five hospitals with particular guideline recommendations for specific clinical problems such as bacterial resistance and surgical antibiotic prophylaxis.

The aim of this study was to investigate how dietary supplementation of tea polyphenols (TP) and tea catechins (TC) affect laying performance, albumen quality, ovomucin composition, and magnum morphology of laying hens in the late phase of production. Two hundred seventy Hy-Line Brown laying hens (64 wk old) were assigned to a basal diet (the control), the basal diet supplemented with 200 mg/kg tea polyphenols (TP200) or 200 mg/kg tea catechins (TC200). Each treatment had 6 replicates with 15 hens each. The feeding trial lasted 10 wks. Over the course of the trial, dietary supplementation with TP200 significantly increased the egg production (EP) and improved the feed conversion ratio (FCR) in wk 6 to 10 and wk 1 to 10 (P < 0.05). The albumen height and the Haugh unit (HU) of hens fed TP200 were higher than those of hens fed the control diet at wks 8 and 10 (P < 0.05). However, there were no significant differences in the albumen height and the HU between the TP200 and TC200 groups (P > 0.05). The SDS-PAGE analysis indicated that bands of the ovomucin fractions in the TP200 group had the highest intensity compared with those of the control and TC200 groups. Compared with the control, there was a significant increase in protein sulfhydryl (SH) content of the albumen in the TP200 group at the end of experiment, while a significant decrease in protein carbonyl content and protein surface hydrophobicity (P < 0.05). There were also obvious increase in the height and width of the primary folds, epithelial cell height, and cilia height of the simple columnar epithelium in the TP200 group compared with the control and TC200 groups (P < 0.05). In conclusion, dietary supplementation with 200 mg/kg TP can improve performance, albumen quality, and magnum morphology of aged hens. In addition, TP rather than TC could improve the health status of the magnum for aged layers.

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