A new self-assembled and self-healing class of metal free, recyclable, heterogeneous Brønsted acid catalysts has been developed by the protonation aniline derivatives (tetrakis(4-aminophenyl)methane, leuco-crystal violet, benzidine, p-phenylenediamine) with aromatic sulfonic acids (tetrakis(phenyl-4-sulfonic acid)methane, 2,6-naphthalenedisulfonic acid). As a result, five three-dimensional crys...

We investigate the OH-stretching overtone dynamics of fluorosulfonic acid (FSO(3)H) and chlorosulfonic acid (ClSO(3)H) using classical trajectory simulations. The initial nuclear coordinates and momenta for the trajectories are sampled from anharmonic correlation-corrected vibrational self consistent field (CC-VSCF) wavefunctions. We consider both OH-stretching overtone states and combination s...

Presented here is a first principles based molecular modeling investigation of the possible role of the side chain in effecting proton transfer in the short-side-chain perfluorosulfonic acid fuel cell membrane under minimal hydration conditions. Extensive searches for the global minimum energy structures of fragments of the polymer having two pendant side chains of distinct separation (with che...

Union Carbide Witco Chemical Aerosol 22 Aerosol A-102 Aerosol 18 Aerosol OS Cyanamer P-35 Ethofat 242/25 Ethofat C/15 Ethomid HT/60 Ethomeen 18/60 Merpol DA Zelec DX Duponol ST Merpol F Alkanol S Flakes Duponol WA Dry Duponol WA Paste Duponol WAQ Duponol ME Dry FC-134 FC-170 FC-172 LSD-2 LSD-6 Dequest 2000 Dequest 2006 EMA Grade 11 EMA Grade 61 ID-2721 Lomar PW Nopcosant L Tamol SN Tamol 731-25...

Peptide binding by class II major histocompatibility complex proteins is generally enhanced at low pH in the range of hydrogen ion concentrations found in the endosomal compartments of antigen-presenting cells. We and others have proposed that class II molecules undergo a reversible conformational change at low pH that is associated with enhanced peptide loading. However, no one has previously ...

The stability of proteins under co-solvent conditions is dependant on the nature of the co-solvent; the co-solvent can alter a protein's properties and structural effects through bimolecular interactions between its functional groups and co-solvent particles. Ionic liquids (ILs) represent a rather diverse class of co-solvents that are combinations of different ions, which are liquids at or clos...

The title hydrated mol-ecular salt, C4H12N+·C4H5O6-·H2O, was prepared by deprotonation of enanti-opure l-tartaric acid with racemic sec-butyl-amine in water. Only one enanti-omer was observed crystallographically, resulting from the combination of (S)-sec-butyl-amine with l-tartaric acid. The sec-butyl-ammonium moiety is disordered over two conformations related by rotation around the CH-CH2 bo...

A marked inhibition of the incorporation of S(35)-sulfate by normal calf costal cartilage was produced by potassium ascorbate in the presence of catalytic amounts of cupric ions. The effect of the various components of the ascorbic acid oxidizing system (potassium ascorbate, cupric ions, cuprous ions, hydrogen peroxide, dehydroascorbic acid) was investigated. The results of experiments in which...

The coronary vasodilator effect of bradykinin (BK) in the rat is independent of NO but dependent on activation of phospholipases with involvement of cytochrome P450 mono-oxygenase (P450) and stimulation of Ca++-activated K+ channels, implicating an unidentified hyperpolarizing factor generated via P450 metabolism of arachidonic acid (AA). Because P450 activity also generates free radicals, such...