Below an embryo MC of 0.1 g H(2)O g(-1) dw, dormancy release was faster Selleck GSK1838705A at 15 degrees C than at higher temperatures. This suggests that dormancy release at low MC was associated

with negative activation energy, supported by Arrhenius plots, and low Q(10) values. At higher MC, the rate of dormancy alleviation increased with temperature, correlating well with the temperature dependence of biochemical processes. These findings suggests the involvement of two distinct cellular mechanisms in dormancy release; non-enzymatic below 0.1 g H(2)O g(-1) dw and associated with active metabolism above this value. The effects of temperature on seed dormancy release above the threshold MC were analysed using a population-based thermal time approach and a model predicting the rate of dormancy alleviation is provided. Sunflower embryo dormancy release was effective at temperatures above 8 degrees C (the base temperature for after-ripening, Tb(AR), was 8.17 degrees C), and the higher the

after-ripening temperature above this threshold value, the higher was the rate of dormancy loss. Thermodynamic analyses of water sorption isotherms revealed that dormancy release was associated with less 5-Fluoracil in vivo bound water and increased molecular mobility within the embryonic axes but not the cotyledons. It is proposed that the changes in water binding properties result from oxidative processes and can, in turn, allow metabolic activities.”
“We investigate the pinning of domain walls in ferroelectrics on the basis of the two phonon bound state (TPBS) or discrete breather state due to impurity energy levels above the phonon continua in ferroelectrics such as this website LiNbO3 in order to show the pinning transition, which indicates the point of easiest switching. We predict, with the help of our quantum calculations, that every ferroelectric material has such a critical point of easy switching. Here we

describe the quantum origin of pinning through the findings of analytical and numerical calculations, as interpreted by a TPBS concept by such impurity or nonlinearity induced modes, by plotting various TPBS parameters against the Landau coefficient and percent impurity content. This new approach might lead to many interesting applications for device manufacturing. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3607298]“
“alpha-secretase is the name for a metalloprotease activity, which is assumed to play a key role in the prevention of the molecular mechanisms underlying Alzheimer’s disease (AD). Proteases similar to alpha-secretase are essential for a wide range of biological processes, such as cell adhesion and embryonic development. The molecular culprit in AD is the amyloid beta peptide (A beta), which derives from the amyloid precursor protein (APP) through sequential cleavage by the two proteases beta- and gamma-secretase.