Thermoplastic elastomers (TPEs) composed of ABA block polymers exhibit a wide variety of properties and are easily processable as they contain physical, rather than chemical, cross-links. Poly(γ-methyl-ε-caprolactone) (PγMCL) is an amorphous polymer with a low entanglement molar mass (M = 2.9 kg mol), making it a suitable choice for tough elastomers. Incorporating PγMCL as the midblock with polylactide (PLA) end blocks (f = 0.17) results in TPEs with high stresses and elongations at break (σ = 24 ± 2 MPa and ε = 1029 ± 20%, respectively) and low levels of hysteresis. The use of isotactic PLA as the end blocks (f = 0.17) increases the strength and toughness of the material (σ = 30 ± 4 MPa, ε = 988 ± 30%) due to its semicrystalline nature. This study aims to demonstrate how the outstanding properties in these sustainable materials are a result of the entanglements, glass transition temperature, segment-segment interaction parameter, and crystallinity, resulting in comparable properties to the commercially relevant styrene-based TPEs.

Background The tobacco industry denies that their marketing is targeted at young nonsmokers, but it seems more probable that tobacco advertising and promotion influences the attitudes of nonsmoking adolescents, and makes them more likely to try smoking. Objectives To assess the e ects of tobacco advertising and promotion on nonsmoking adolescents' future smoking behaviour.

Thermoplastic elastomers are attractive materials because of their ability to be melt-processed, reused, and recycled, unlike chemically cross-linked elastomers such as rubber. We report the synthesis and mechanical properties of polyolefin-based thermoplastic elastomer block copolymers. A simple one-pot procedure is employed, using a living arylnaphthyl-α-diimine Ni(II) "sandwich" complex to generate high crystallinity hard blocks from 1-decene and low crystallinity soft blocks from ethylene. Various block structures are accessed, ranging from a diblock up to a heptablock copolymer. Statistical copolymers of 1-decene and ethylene are also synthesized for comparison. All resulting polymers behave as elastomers, with properties that modulate with hard and soft block composition, block architecture, and polymerization solvent. Triblock copolymers demonstrate strain at break values up to 750%, with elastic strain recoveries up to 85%. Interestingly, statistical copolymers demonstrate strain at break values upward of 1120% and elastic strain recoveries up to 77%. Creep experiments were performed to determine the resilience of these materials to deformation. It is found that higher block architectures (triblock and above) have greater resistance to strain-induced deformation than lower block architectures (diblock and statistical).

The observed cross-sectional associations suggest that snack consumption is a risk factor for poor diet, but unless energy-dense foods are consumed, snacking does not consistently contribute to overweight in US adolescents.

In this autopsy series, only 2 of 12 patients with unexplained sudden death were observed to have a defect in HERG among five candidate genes tested. It is likely that elucidation of SCD mechanisms in such patients will await the discovery of multiple, novel arrhythmia-causing gene defects.