Determination of Conformational Equilibria in Proteins Using Residual Dipolar Couplings

In order to carry out their functions, proteins often undergo significant conformational fluctuations that enable them to interact with their partners. The accurate characterization of these motions is key in order to understand the mechanisms by which macromolecular recognition events take place. Nuclear magnetic resonance spectroscopy offers a variety of powerful methods to achieve this result. We discuss a method of using residual dipolar couplings as replica-averaged restraints in molecular dynamics simulations to determine large amplitude motions of proteins, including those involved in the conformational equilibria that are established through interconversions between different states. By applying this method to ribonuclease A, we show that it enables one to characterize the ample fluctuations in interdomain orientations expected to play an important functional role.     

Poly(diol-co-citrate)s as novel elastomeric perivascular wraps for the reduction of neointimal hyperplasia

The synthesis of poly(diol-co-citrate) elastomers that are biocompatible with vascular cells and can modulate the kinetics of the NO release based on the diol of selection is reported. NO-mediated cytostatic or cytotoxic effects can be controlled depending on the NO dose and the exposure time. When implanted in vivo in a rat carotid artery injury model, these materials demonstrate a significant reduction of neointimal hyperplasia. This is the first report of a NO-releasing polymer fabricated in the form of an elastomeric perivascular wrap for the treatment of neointimal hyperplasia. These elastomers also show promise for other cardiovascular pathologies where NO-based therapies could be beneficial.     

Characterization of essential oil and effects on growth of Verbena gratissima plants treated with homeopathic phosphorus

Plant models offer a method to examine the efficacy of homeopathic solutions. Homeopathic Phosphorus (P) dynamizations were evaluated on the linear growth and dry biomass of Verbena gratissima, a plant native to Brazil. The yields and chemical characterization of the essential oil are also given. Plants exhibited phenotypic plasticity after the homeopathic Phosphorus treatments. The dynamization 9CH, in particular, interfered with plant growth, height, diameter of stems and total dry mass. 9CH treatment showed the highest yield of essential oil. The essential oil composition of V. gratissima varied according to the different dynamization used. Homeopathic Phosphorus provided the greatest amount of beta-pinene, trans-pinocarveol, trans-pinocamphone and trans-pinocarvyl acetate in comparison with controls.     

On site validation of sound absorption measurements of occupied pews

Laboratory measurements of sound absorption by audiences are known to be scarcely reliable when applied to actual rooms as a consequence of several problems, among which the different area of the “sample” and the different distribution of the reflected sound may play important roles. When dealing with worship places, characterized by a variable degree of occupation and much lower absorption due to unoccupied seats, things become more complicated as absorption seems to be proportional to the number of occupants rather than to the area they cover (as normally accepted in performing spaces). The combination of these variables has been investigated by taking advantage of laboratory measurements and analysing their application to six churches, where on site measurements of reverberation time were carried out with and without occupation. The results are discussed both in terms of simple prediction formulae (Sabine, Eyring, and Arau-Purchades) and of computer simulations, showing that laboratory measurements may be reliably used in computer simulations (at least in the frequency range from 500 Hz on). At low frequencies greater attention must be paid as the absorption coefficients need to be corrected as a function of the actual distribution of the sound field in the room.     

Hydrogen oxidation reaction at the Ni/YSZ anode of solid oxide fuel cells from first principles

By means of ab initio simulations we here provide a comprehensive scenario for hydrogen oxidation reactions at the Ni/zirconia anode of solid oxide fuel cells. The simulations have also revealed that in the presence of water chemisorbed at the oxide surface, the active region for H oxidation actually extends beyond the metal/zirconia interface unraveling the role of water partial pressure in the decrease of the polarization resistance observed experimentally.     

Organic light‐emitting transistors with voltage‐tunable lit area and full channel illumination

Organic light‐emitting transistors (OLETs) are multifunctional optoelectronic devices that hold great promise for a variety of applications, including flat panel displays, integrated light sources for sensing and optical communication systems. The narrow illumination area within the device channel is considered intrinsic to the device architecture and is a severe technological drawback for all those applications where a controlled, wide and homogeneous emission area is required. Here it is shown that not only the position but also the extension of the emission area is voltage‐tunable, and the entire channel of the transistor can be homogeneously illuminated. The modeling of the exciton distribution within the channel at the different bias conditions coupled to the modeling of the device emission profile highlights that excitons are spread through the entire channel width and across the bulk of the central emission layer of the p‐channel/emitter/n‐channel trilayer active heterostructure.