@article {2399, title = {Orientational order of near D-3h solutes in nematic liquid crystals}, journal = {Journal of Chemical Physics}, volume = {130}, number = {15}, year = {2009}, note = {ISI Document Delivery No.: 437KLTimes Cited: 2Cited Reference Count: 49Danilovic, Zorana Burnell, E. Elliott}, month = {Apr}, pages = {11}, type = {Article}, abstract = {Solutes that are similar in size, have a shape that is close to D-3h symmetry but contain dissimilar substituent groups (methyl versus chloro, contributing different electrostatic interactions to the anisotropic intermolecular potential), are used to delineate the short- and long-range anisotropic intermolecular interactions that lead to solute orientational order in nematic liquid crystals. The short-range interactions should be similar for all solutes and for D-3h symmetry should yield a single independent order parameter, whereas the long-range interactions are expected to differ with solute. Short-range size and shape mechanisms account for solute orientational order measured in magic mixtures (e.g., 55 wt \% ZLI-1132/N-p-ethoxybenzylidene-p({\textquoteright})-n-butylaniline), whereas additional mechanisms are required in other nematic liquid-crystal solvents. The results obtained for long-range interactions cannot be rationalized in detail using simple mean-field models that incorporate solute dipoles, quadrupoles, or polarizabilities. The results suggest that details of the solute electrostatics may need to be incorporated into the description of the anisotropic intermolecular potential.}, keywords = {AB-INITIO, ELECTRIC-FIELD GRADIENT, electrostatic, interactions, liquid crystals, LIQUID MIXTURES, liquid structure, MEAN TORQUE, molecular orientation, MOLECULAR-HYDROGEN, MONTE-CARLO SIMULATIONS, nematic, NMR, polarisability, POTENTIALS, SHAPE, SOLVENTS}, isbn = {0021-9606}, url = {://000265486300032}, author = {Danilovic, Z. and Burnell, E. E.} } @article {2026, title = {Mechanisms of solute orientational order in nematic liquid crystals}, journal = {Journal of Chemical Physics}, volume = {128}, number = {16}, year = {2008}, note = {ISI Document Delivery No.: 295DXTimes Cited: 7Cited Reference Count: 51Burnell, E. Elliott ter Beek, Leon C. Sun, Zhengmin}, month = {Apr}, pages = {10}, type = {Article}, abstract = {The order parameters of a number of different solutes dissolved in a number of different nematic liquid-crystal solvents are measured and compared. It is shown that the order parameters can all be rationalized with the ansatz that there exist two independent ordering mechanisms operating in the liquid crystals employed. With this ansatz it is possible to fit the experimental order parameters to better than 5\%. This opens the possibility of the accurate prediction of order parameters in ordered liquids. (c) 2008 American Institute of Physics.}, keywords = {ELECTRIC-DIPOLE INTERACTIONS, electrostatic, FIELD GRADIENT, interactions, KRISTALLINFLUSSIGEN PHASE, MEAN TORQUE, MOLECULAR-STRUCTURE, MOLEKULAR-STATISTISCHE THEORIE, MONTE-CARLO SIMULATIONS, NMR, SOLVENTS}, isbn = {0021-9606}, url = {://000255456300083}, author = {Burnell, E. E. and ter Beek, L. C. and Sun, Z. M.} } @article {713, title = {Characterizing the pH-dependent stability and catalytic mechanism of the family 11 xylanase from the alkalophilic Bacillus agaradhaerens}, journal = {Carbohydrate Research}, volume = {338}, number = {5}, year = {2003}, note = {ISI Document Delivery No.: 645XBTimes Cited: 6Cited Reference Count: 38}, month = {Feb}, pages = {415-421}, type = {Article}, abstract = {The xylanase, BadX, from the alkalophilic Bacillus agaradhaerens was cloned, expressed and studied in comparison to a related family 11 xylanase, BcX, from B. circulans. Despite the alkaline versus neutral conditions under which these bacteria grow, BadX and BcX both exhibit optimal activity near pH 5.6 using the substrate omicron-nitrophenyl beta-xylobioside. Analysis of the bell-shaped activity profile of BadX yielded apparent pK(a) values of 4.2 and 7.1, assignable to its nucleophile Glu94 and general acid Glu184, respectively. In addition to having an similar to 10-fold higher k(cat)/K-m value with this substrate at pH 6 and 40 degreesC, BadX has significantly higher thermal stability than BcX under neutral and alkaline conditions. This enhanced stability, rather than a shift in its pH-optimum, may allow BadX to hydrolyze xylan under conditions of elevated temperature and pH. (C) 2003 Elsevier Science Ltd. All rights reserved.}, keywords = {bacillus xylanase, CIRCULANS XYLANASE, CLASSIFICATION, electrostatic, extremophile, glycosidase, GLYCOSYL-ENZYME INTERMEDIATE, HYDROLASES, interactions, NMR ASSIGNMENTS, pH-dependent mechanism, PK(A), PROTEIN, STABILITY, THERMOSTABILITY}, isbn = {0008-6215}, url = {://000181004800004}, author = {Poon, D. K. Y. and Webster, P. and Withers, S. G. and McIntosh, L. P.} } @article {2981, title = {DIELECTRIC-RELAXATION OF ELECTROLYTE-SOLUTIONS - MOLECULAR-DYNAMICS AND THEORETICAL RESULTS FOR IONS IN SIMPLE DIPOLAR SOLVENTS}, journal = {Journal of Chemical Physics}, volume = {100}, number = {11}, year = {1994}, note = {ISI Document Delivery No.: NN731Times Cited: 25Cited Reference Count: 21}, month = {Jun}, pages = {8385-8391}, type = {Article}, abstract = {Computer simulation and theoretical results are given for the frequency dependent dielectric function of model electrolyte solutions. The influences of salt concentration, ionic charge, and solvent dipole moment are discussed. It is found that a substantial salt induced dielectric decrement; persists up to the dispersion frequency. At higher frequencies, however, the dielectric constant-of the solution is larger;than that of the solvent giving a salt induced dielectric increment.}, keywords = {COMPUTER-SIMULATION, CONDUCTIVITY, CONSTANT, ELECTRICAL-PROPERTIES, electrostatic, LIQUIDS, PERIODIC BOUNDARY-CONDITIONS, SYSTEMS}, isbn = {0021-9606}, url = {://A1994NN73100060}, author = {Chandra, A. and Patey, G. N.} } @article {2748, title = {DIELECTRIC-RELAXATION OF DIPOLAR LIQUIDS}, journal = {Journal of Chemical Physics}, volume = {99}, number = {3}, year = {1993}, note = {ISI Document Delivery No.: LN782Times Cited: 19Cited Reference Count: 33}, month = {Aug}, pages = {2068-2073}, type = {Article}, abstract = {An approximate expression is derived for the dielectric function epsilon(k, omega). The theory includes inertial and non-Markovian effects and is free of adjustable parameters. For the k = 0 case, detailed comparisons are made with computer simulation results for dipolar soft-sphere and Stockmayer fluids, and the theory is shown to be qualitatively sound at both low and high frequencies. The present approximation should be very useful in developing a theory of solvation dynamics which properly includes important inertial effects.}, keywords = {COMPUTER-SIMULATION, electrostatic, equation, INVARIANT EXPANSION, ION SOLVATION, LIQUIDS, MEAN SPHERICAL MODEL, MOLECULAR LIQUIDS, ORNSTEIN-ZERNIKE, PERIODIC BOUNDARY-CONDITIONS, POLAR, SOLVATION DYNAMICS, SYSTEMS}, isbn = {0021-9606}, url = {://A1993LN78200067}, author = {Chandra, A. and Wei, D. Q. and Patey, G. N.} }