Neutron and proton densities in the nuclear periphery are investigated within (p,n) charge-exchange isobar transitions. For this purpose we have developed parameterfree optical potentials 1) with a detailed treatment of the in-medium tτ part of the effective interaction. Non local coupled-channel Lane equations are solved to obtain the scattering observables. The use of conventional proton and ...

New proton exchange membrane (PEM) materials with high proton conductivities at elevated temperatures (ca. > 150 °C) offer the promise of improving PEM fuel cell operation. Higher operating temperatures would provide several benefits including: (i) improved resistance to carbon monoxide poisoning of the platinum (Pt) electrocatalyst at the anode, (ii) reduced need for feed-stream heat and humid...

Modulated proton transport plays significant roles in biological processes such as ATP synthesis as well as in technologically important applications including, for example, hydrogen fuel cells. The state-of-the-art proton-exchange membrane is the sulphonated tetrafluoroethylene copolymer Nafion developed by DuPont in the late 1960s, with a high proton conductivity. However, actively switchable...

Pancreatic β-cell imaging would be useful in monitoring the progression of and therapies for diabetes. The purpose of this study was to develop and evaluate quantitative β-cell MRI using manganese (Mn(2+)) labeling of β cells, T1 mapping, and a two-site water exchange model. Normal, pharmacologically-treated, and severely diabetic mice underwent injection of MnCl(2). Pancreatic water proton T1 ...

In arbuscular mycorrhizal (AM) symbiosis, fungi and plants exchange nutrients (sugars and phosphate, for instance) for reciprocal benefit. Until now it is not clear how this nutrient exchange system works. Here, we used computational cell biology to simulate the dynamics of a network of proton pumps and proton-coupled transporters that are upregulated during AM formation. We show that this mini...

We present a site-resolved study of slow (ms to s) motions in a protein in the solid (microcrystalline) state performed with the use of a modified version of the centerband-only detection of exchange (CODEX) NMR experiment. CODEX was originally based on measuring changes in molecular orientation by means of the chemical shift anisotropy (CSA) tensor, and in our modification, angular reorientati...

The effects of ethanol, ethylene glycol, dioxane, and other organic co-solvents upon the hydrogen exchange rates of randomly coiled oxidized RNase, native RNase, and native trypsin have been measured. The exchange rate of oxidized RNase, the model compound for the proton transfer step in hydrogen exchange, is decreased by all of the co-solvents studied at temperatures in the range 3-20 degrees....

Magnetic susceptibility and proton magnetic resonance spectra are reported for the oxidized and reduced forms of the iron-sulfur protein Bacillus polymyxa ferredoxin I. The magnetic susceptibility of the oxidized form indicates antiferromagnetic exchange coupling between component iron atoms that is quantitatively similar to that observed for the clostridial ferredoxins and for the [(C(2)H(5))(...

Introduction: Recently, an indirect MRI detection of hydroxyl protons of small metabolites via the water signal was reported [1]. Selective off-resonance irradiation attenuates the water signal via chemical exchange saturation transfer (CEST) between hydroxyl and water protons. It was found that the magnetisation transfer (MT) asymmetry ratio (MTRasym) depends nonlinearly on hydroxyl-group conc...