@article {2656, title = {Solute order parameters in liquid crystals from NMR spectra solved with evolutionary algorithms: Application of double Maier-Saupe Kobayashi-McMillan theory}, journal = {Chemical Physics Letters}, volume = {476}, number = {1-3}, year = {2009}, note = {ISI Document Delivery No.: 463YQTimes Cited: 2Cited Reference Count: 25Weber, Adrian C. J. Yang, Xuan Dong, Ronald Y. Meerts, W. Leo Burnell, E. Elliott}, month = {Jul}, pages = {116-119}, type = {Article}, abstract = {We obtain dipolar couplings via a novel application of evolutionary algorithms solving for multiple spin-systems simultaneously and automatically from the NMR spectra of several solutes in several nematic and smectic liquid crystal solvents. The order parameters obtained from the dipolar couplings are used to test a novel Hamiltonian that includes two Maier-Saupe nematic terms plus Kobayashi-McMillan smectic A terms. It is shown that this Hamiltonian can rationalize the NMR experiments with physically reasonable smectic order parameters and Hamiltonian prefactors. (C) 2009 Elsevier B.V. All rights reserved.}, keywords = {ELECTRON-DIFFRACTION, MOLECULAR-STRUCTURES, NEMATIC SOLVENTS, orientational order, PHASE, SHAPE}, isbn = {0009-2614}, url = {://000267470600025}, author = {Weber, A. C. J. and Yang, X. and Dong, R. Y. and Meerts, W. L. and Burnell, E. E.} } @article {2256, title = {Bridging the gap between phenomenology and microscopic theory: Asymptotes in nematic colloids}, journal = {Physical Review E}, volume = {77}, number = {4}, year = {2008}, note = {ISI Document Delivery No.: 295EDTimes Cited: 3Cited Reference Count: 28Sokolovska, T. G. Sokolovskii, R. O. Patey, G. N.Part 1}, month = {Apr}, pages = {10}, type = {Article}, abstract = {The Ornstein-Zernike equation is applied to nematic colloids with up-down symmetry to determine how the electrostatic analogy and other phenomenological results appear in molecular theory. In contrast to phenomenological approaches, the molecular theory does not assume particular boundary conditions (anchoring) at colloidal surfaces. For our molecular parameters the resulting anchoring appears to be realistic, neither rigid nor infinitely weak. For this case, the effective force between a colloidal pair at large separation remains essentially constant over the entire region of nematic stability. We show that a simple van der Waals approximation gives a potential of mean force that in some important aspects is similar to the phenomenological results obtained in the limit of weak anchoring; at large separations the potential varies as Sigma(8), where Sigma is the colloidal diameter. In contrast, the more sophisticated mean spherical approximation yields a Sigma(6) dependence consistent with phenomenological calculations employing rigid boundary conditions. We show that taking proper account of the correlation (or magnetic coherence) length xi inherent in the nematic sample is essential in an analysis of the Sigma dependence. At infinite xi the leading Sigma dependence is Sigma(6), but this shifts to Sigma(8) when xi is finite. The correlation length also influences the orientational behavior of the effective interaction. The so-called quadrupole interaction that determines the long-range behavior at infinite xi transforms into a superposition of screened "multipoles" when xi is finite. The basic approach employed in this paper can be readily applied to a broad range of physically interesting systems. These include patterned and nonspherical colloids, colloids trapped at interfaces, and nematic fluids in confined geometries such as droplets.}, keywords = {ELASTIC-CONSTANTS, FIELD, FORCES, LIQUID-CRYSTALS, PARTICLES, PHASE, STATISTICAL-THEORY, TOPOLOGICAL DEFECTS}, isbn = {1539-3755}, url = {://000255456900069}, author = {Sokolovska, T. G. and Sokolovskii, R. O. and Patey, G. N.} } @article {2007, title = {Microstructural effects on the formation and degradation of zinc phosphate coatings on 2024-Al alloy}, journal = {Applied Surface Science}, volume = {254}, number = {15}, year = {2008}, note = {ISI Document Delivery No.: 295YWTimes Cited: 2Cited Reference Count: 26Akhtar, A. S. Wong, P. C. Wong, K. C. Mitchell, K. A. R.}, month = {May}, pages = {4813-4819}, type = {Article}, abstract = {The formation of zinc phosphate (ZPO) coatings on 2024-T3 aluminum alloy was studied using scanning electron microscopy (SEM), scanning Auger microscopy (SAM) and X-ray photoelectron spectroscopy (XPS), with an emphasis on microstructural effects involving second-phase particles and the alloy matrix. Surface polishing results in an Al-Cu-Mg particle surface that contains metallic Cu as well as an overlayer of aluminum and magnesium oxide, while larger amounts of aluminum oxide are present on the Al-Cu-Fe-Mn particle and matrix. When dipped in an acidic ZPO coating solution, the oxide covering the Al-Cu-Mg particle is etched most easily, and metallic Cu near the surface makes that region most cathodic, allowing more coating deposition compared with the other regions. The oxides on the Al-Cu-Fe-Mn and matrix regions are similar, thereby confirming that the observed differences in ZPO coating characteristics at these two regions arise from their underlying electrochemical characteristics. Immersion of a coated 2024-Al sample in corrosive NaCl solution for extended periods indicates that the ZPO provides better protection to the second-phase particles than to the matrix. (C) 2008 Elsevier B.V. All rights reserved.}, keywords = {7075-T6, ALKALINE STABILITY, aluminum alloy, ALUMINUM-ALLOY, Auger electron spectroscopy, BEHAVIOR, corrosion, CORROSION PROTECTION, INITIATION, MICROSTRUCTURE, NI2+, PARTICLES, PHASE, surface oxide, zinc phosphating}, isbn = {0169-4332}, url = {://000255511700063}, author = {Akhtar, A. S. and Wong, P. C. and Wong, K. C. and Mitchell, K. A. R.} } @article {1567, title = {Colloidal interactions in nematic fluids}, journal = {Physical Review E}, volume = {73}, number = {2}, year = {2006}, note = {ISI Document Delivery No.: 017AUTimes Cited: 4Cited Reference Count: 26Part 1}, month = {Feb}, pages = {4}, type = {Article}, abstract = {Microscopic theory is used to obtain effective interactions between colloidal particles in nematic fluids subjected to an external orienting field. It is shown that the field can dramatically change the effective intercolloidal interactions without altering the symmetry of the director configuration around a single particle. Our calculations suggest that a rich variety of colloidal structures can be promoted by varying the external field.}, keywords = {FORCES, PHASE, TOPOLOGICAL DEFECTS}, isbn = {1539-3755}, url = {://000235667300009}, author = {Sokolovska, T. G. and Sokolovskii, R. O. and Patey, G. N.} } @article {1566, title = {Nematic-fluid structure in wall-field geometry. II. The direct correlation function}, journal = {Journal of Chemical Physics}, volume = {125}, number = {3}, year = {2006}, note = {ISI Document Delivery No.: 065QNTimes Cited: 4Cited Reference Count: 20Sokolovska, T. G. Sokolovskii, R. O. Patey, G. N.}, month = {Jul}, pages = {11}, type = {Article}, abstract = {An explicit expression for the wall-nematic direct correlation function (DCF) is obtained for any orientation of the wall with respect to an external orienting field. It is found that inside the surface of the wall, the DCF rapidly tends to a function of the nematogen orientation and depends only on parameters of the bulk fluid. We suggest that the wall-nematic DCF can be used as an ansatz for the colloid-nematic DCF in dilute nematic colloids. The reliability of this ansatz is investigated at different field strengths in both isotropic and nematic regions. Our calculations for spherical colloidal particles show that this approximation is valid for colloidal particles that are large, but well within the physically realistic size range. The ansatz could also be applied to nonspherical colloidal particles.}, keywords = {INTEGRAL-EQUATION, PHASE}, isbn = {0021-9606}, url = {://000239174500045}, author = {Sokolovska, T. G. and Sokolovskii, R. O. and Patey, G. N.} } @article {1602, title = {Search for suitable approximation methods for fullerene structure and relative stability studies: Case study with C50}, journal = {J. Chem. Phys.}, volume = {125}, number = {9}, year = {2006}, note = {ISI Document Delivery No.: 081XSTimes Cited: 13Cited Reference Count: 48Tian, Wei Quan Feng, Ji-Kang Wang, Yan Alexander Aoki, Yuriko}, month = {Sep}, pages = {094105}, type = {Article}, abstract = {

Local density approximation (LDA), several popular general gradient approximation (GGA), hybrid module based density functional theoretical methods: SVWN, BLYP, PBE, HCTH, B3LYP, PBE1PBE, B1LYP, and BHandHLYP, and some nonstandard hybrid methods are applied in geometry prediction for C-60 and C-70. HCTH with 3-21G basis set is found to be one of the best methods for fullerene structural prediction. In the predictions of relative stability of C-50 isomers, PM3 is an efficient method in the first step for sorting out the most stable isomers. HCTH with 3-21G predicts very good geometries for C-50, similar to the performance of B3LYP/6-31G(d). The gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital from the predictions of all the density functional theory methods has the following descending order: E-gap(half-and-half hybrid)\> E-gap(B3LYP)\> E-gap(HCTH)(GGA)\> E-gap(SVWN)(LDA). (c) 2006 American Institute of Physics.

}, keywords = {ADJUSTABLE-PARAMETERS, BUCKMINSTERFULLERENE, C-70, DENSITY-FUNCTIONAL THEORY, ELECTRON-DIFFRACTION, ENERGIES, GENERALIZED GRADIENT APPROXIMATION, MOLECULAR-STRUCTURE, PERFORMANCE, PHASE, SEMIEMPIRICAL METHODS}, isbn = {0021-9606}, url = {://000240351500008}, author = {W. Q. Tian* and J.-K. Feng and Wang, Y. A. and Aoki, Y.} } @article {1584, title = {Testing assumptions about solute concentration dependence in liquid crystal NMR}, journal = {Journal of Physical Chemistry B}, volume = {110}, number = {3}, year = {2006}, note = {ISI Document Delivery No.: 008NATimes Cited: 2Cited Reference Count: 24}, month = {Jan}, pages = {1363-1368}, type = {Article}, abstract = {The NMR spectra of four solutes, used as probes of liquid crystal orientational order, were analyzed. For each solute, samples were prepared at different solute concentrations, and the concentration dependence was used to extrapolate zero-concentration properties. The mean-field (Maier-Saupe) model when applied to solutes neglects solute-solute interactions and assumes all solutes in a mixed-solute sample see the same average environment. The first assumption is only valid as one approaches zero concentration, while experiments are typically carried out at concentrations between 0 and 10 mol \%. The solute concentration dependence has in the past been "scaled out" using an internal solute reference as an orientational standard. We measured the concentration dependence of the orientational order parameter and calculate the corresponding interaction energies based on a mean-field interaction potential for a solute. We find agreement at the 3\% level between experiments for different solutes while using (i) the zero-concentration values as solute-dependent orientational references and (ii) scaling to either order parameters or interaction energies; these two scalings gave equivalent but not identical results. We find, too, that errors inherent in the experiment and the calculations will limit attempts to refine the theory to push the comparisons beyond the 2\% level.}, keywords = {ANISOTROPIES, ELASTOMERS, ELECTRON-DIFFRACTION, MOLECULAR-STRUCTURE, ORDER, ORIENTATION, PHASE, SPECTRA}, isbn = {1520-6106}, url = {://000235046300041}, author = {Taggar, A. S. and Campbell, C. J. and Yethiraj, A. and Burnell, E. E.} } @article {1259, title = {Colloid-induced structure in liquid crystal media}, journal = {Journal of Chemical Physics}, volume = {122}, number = {12}, year = {2005}, note = {ISI Document Delivery No.: 915HDTimes Cited: 7Cited Reference Count: 26}, month = {Mar}, pages = {8}, type = {Article}, abstract = {The structural perturbations induced by colloidal particles immersed in a model nematic subjected to an external field are calculated employing integral equation methods. Maps of the density-orientational distribution about a colloidal particle are obtained, and these provide a microscopic picture of the colloid{\textquoteright}s nematic coat. We focus on colloidal particles that favor homeotropic anchoring, but planar anchoring cases are also considered. The range and structure of the nematic coat is shown to be significantly influenced by the nature of the anchoring, the size of the colloidal particle, the range and strength of the colloid-nematogen interaction, and the external field strength. All of these factors are discussed.}, keywords = {FIELD, FLUIDS, INTEGRAL-EQUATION THEORY, PHASE, SIMULATION, SPHERICAL-PARTICLE, TOPOLOGICAL DEFECTS}, isbn = {0021-9606}, url = {://000228287900062}, author = {Sokolovska, T. G. and Sokolovskii, R. O. and Patey, G. N.} } @article {1059, title = {Homoleptic, sigma-bonded octahedral [M(CO)(6)](2+) cations of iron(II), ruthenium(II), and osmium(II): Part 1: Syntheses, thermochemical and vibrational characterizations, and molecular structures as [Sb2F11](-) and [SbF6](-) salts. A comprehensive, compa}, journal = {Inorganic Chemistry}, volume = {44}, number = {12}, year = {2005}, note = {ISI Document Delivery No.: 934LPTimes Cited: 5Cited Reference Count: 100}, month = {Jun}, pages = {4189-4205}, type = {Article}, abstract = {Homoleptic octahedral, superelectrophilic sigma-bonded metal carbonyl cations of the type [M(CO)(6)](2+) (M = Ru, Os) are generated in the Bronsted-Lewis conjugate superacid HF/SbF5 by reductive carbonylation Of M(SO3F)(3) (M = Ru, Os) or OsF6. Thermally stable salts form with either [Sb2F11](-) or [SbF6](-) as anion, just as for the previously reported [Fe(CO)(6)](2+) cation. The latter salts are generated by oxidative (XeF2) carbonylation of Fe(CO)(5) in HF/ SbF5. A rationale for the two diverging synthetic approaches is provided. The thermal stabilities Of [M(CO)(6)][SbF6](2) salts, studied by DSC, range from 180 degrees C for M = Fe to 350 degrees C for M = Os before decarbonylation occurs. The two triads [M(CO)(6)][SbF6](2) and [M(CO)(6)][Sb2F11](2) (M = Fe, Ru, Os) are extensively characterized by single-crystal X-ray diffraction and vibrational and C-13 NMR spectroscopy, aided by computational studies of the cations. The three [M(CO)(6)][SbF6](2) salts (M = Fe, Ru, Os) crystallize in the tetragonal space group P4/mnc (No. 128), whereas the corresponding [Sb2F11](-) salts are monoclinic, crystallizing in space group P2(1)/n (No. 14). In both triads, the unit cell parameters are nearly invariant of the metal. Bond parameters for the anions [SbF6](-) and [Sb2F11](-) and their vibrational properties in the two triads are completely identical. In all six salts, the structural and vibrational properties of the [M(CO)(6)](2+) cations (M = Fe, Ru, Os) are independent of the counteranion and for the most part independent of M and nearly identical. Interionic C center dot center dot center dot F contacts are similarly weak in all six salts. Metal dependency is noted only in the C-13 NMR spectra, in the skeletal M-C vibrations, and to a much smaller extent in some of the C-O stretching fundamentals (A(1g) and T-1u). The findings reported here are unprecedented among metal carbonyl cations and their salts.}, keywords = {ANTIMONY PENTAFLUORIDE, CRYSTAL-STRUCTURE, ELECTRON-DIFFRACTION, HEXAKIS(CARBONYL)IRON(II), INFRARED SPECTRA, MAS-NMR-SPECTRA, METAL-CARBONYL CATIONS, PHASE, SOLVENT SYSTEM, SUPERACID MEDIA, UNDECAFLUORODIANTIMONATE(V), WEAKLY COORDINATING ANIONS}, isbn = {0020-1669}, url = {://000229710600021}, author = {Bernhardt, E. and Bach, C. and Bley, B. and Wartchow, R. and Westphal, U. and Sham, I. H. T. and von Ahsen, B. and Wang, C. Q. and Willner, H. and Thompson, R. C. and Aubke, F.} } @article {1059, title = {Homoleptic, sigma-bonded octahedral [M(CO)(6)](2+) cations of iron(II), ruthenium(II), and osmium(II): Part 1: Syntheses, thermochemical and vibrational characterizations, and molecular structures as [Sb2F11](-) and [SbF6](-) salts. A comprehensive, compa}, journal = {Inorganic Chemistry}, volume = {44}, number = {12}, year = {2005}, note = {ISI Document Delivery No.: 934LPTimes Cited: 5Cited Reference Count: 100}, month = {Jun}, pages = {4189-4205}, type = {Article}, abstract = {Homoleptic octahedral, superelectrophilic sigma-bonded metal carbonyl cations of the type [M(CO)(6)](2+) (M = Ru, Os) are generated in the Bronsted-Lewis conjugate superacid HF/SbF5 by reductive carbonylation Of M(SO3F)(3) (M = Ru, Os) or OsF6. Thermally stable salts form with either [Sb2F11](-) or [SbF6](-) as anion, just as for the previously reported [Fe(CO)(6)](2+) cation. The latter salts are generated by oxidative (XeF2) carbonylation of Fe(CO)(5) in HF/ SbF5. A rationale for the two diverging synthetic approaches is provided. The thermal stabilities Of [M(CO)(6)][SbF6](2) salts, studied by DSC, range from 180 degrees C for M = Fe to 350 degrees C for M = Os before decarbonylation occurs. The two triads [M(CO)(6)][SbF6](2) and [M(CO)(6)][Sb2F11](2) (M = Fe, Ru, Os) are extensively characterized by single-crystal X-ray diffraction and vibrational and C-13 NMR spectroscopy, aided by computational studies of the cations. The three [M(CO)(6)][SbF6](2) salts (M = Fe, Ru, Os) crystallize in the tetragonal space group P4/mnc (No. 128), whereas the corresponding [Sb2F11](-) salts are monoclinic, crystallizing in space group P2(1)/n (No. 14). In both triads, the unit cell parameters are nearly invariant of the metal. Bond parameters for the anions [SbF6](-) and [Sb2F11](-) and their vibrational properties in the two triads are completely identical. In all six salts, the structural and vibrational properties of the [M(CO)(6)](2+) cations (M = Fe, Ru, Os) are independent of the counteranion and for the most part independent of M and nearly identical. Interionic C center dot center dot center dot F contacts are similarly weak in all six salts. Metal dependency is noted only in the C-13 NMR spectra, in the skeletal M-C vibrations, and to a much smaller extent in some of the C-O stretching fundamentals (A(1g) and T-1u). The findings reported here are unprecedented among metal carbonyl cations and their salts.}, keywords = {ANTIMONY PENTAFLUORIDE, CRYSTAL-STRUCTURE, ELECTRON-DIFFRACTION, HEXAKIS(CARBONYL)IRON(II), INFRARED SPECTRA, MAS-NMR-SPECTRA, METAL-CARBONYL CATIONS, PHASE, SOLVENT SYSTEM, SUPERACID MEDIA, UNDECAFLUORODIANTIMONATE(V), WEAKLY COORDINATING ANIONS}, isbn = {0020-1669}, url = {://000229710600021}, author = {Bernhardt, E. and Bach, C. and Bley, B. and Wartchow, R. and Westphal, U. and Sham, I. H. T. and von Ahsen, B. and Wang, C. Q. and Willner, H. and Thompson, R. C. and Aubke, F.} } @article {866, title = {Molecular weight and polydispersity estimation of adsorbing polymer brushes by atomic force microscopy}, journal = {Langmuir}, volume = {20}, number = {8}, year = {2004}, note = {ISI Document Delivery No.: 811CPTimes Cited: 23Cited Reference Count: 36}, month = {Apr}, pages = {3297-3303}, type = {Article}, abstract = {{We have estimated the molecular weight, M-n, and polydispersity, PDI, of densely grafted poly(N-isopropylacrylamide) (PNIPAM) brushes using a novel atomic force microscopy (AFM) approach. When compression of a polymer brush induced adsorption of multiple chains to an AFM tip, the resulting decompression force profile exhibited a maximum attractive force at a separation, L-m, that decayed to zero with increasing tip-sample separation. We have found that the separation L approximates the average contour length, L,, determined by gel permeation chromatography (GPC). The detection of a decaying attractive force at separations larger than L, suggests that chains of above average length sequentially break free from the tip as they are stretched away from the grafting surface. The shape of the decompression profile in this region approximately paralleled the cumulative weight fraction of the grafted chains determined by GPC. The fraction of chains of a given molecular weight determined from a single force curve fit a log-normal distribution, having a standard deviation that provided an estimate of the PDL We have characterized two PNIPAM brushes by this AFM technique as well as by GPC coupled to a multiangle laser light-scattering detector (MALLS). The values obtained by AFM-(1) Mn,(AFM) = (3.8 +/- 0.5) X 104}, keywords = {ADSORPTION, AFM, CHAIN ELONGATION, ELASTIC PROPERTIES, PHASE, POLY(ACRYLAMIDE), POLY(N-ISOPROPYLACRYLAMIDE), SPECTROSCOPY, SURFACES}, isbn = {0743-7463}, url = {://000220750300044}, author = {Goodman, D. and Kizhakkedathu, J. N. and Brooks, D. E.} } @article {988, title = {Surface-induced ordering of nematics in an external field: The strong influence of tilted walls}, journal = {Physical Review Letters}, volume = {92}, number = {18}, year = {2004}, note = {ISI Document Delivery No.: 818XNTimes Cited: 8Cited Reference Count: 19}, month = {May}, pages = {4}, type = {Article}, abstract = {Microscopic theory is used to investigate surface-induced order in a model nematic subjected to an external orienting field. The wall-particle interaction tends to orient particles perpendicular to the surface. It is shown that if the wall is tilted at similar to45degrees to the field, the reorientational effects can be an order of magnitude larger than those observed for perpendicular or parallel orientations. The surprising observation is associated with the breaking of a particular bulk symmetry. A possible practical application of the tilted geometry is briefly discussed.}, keywords = {CONTACT, FLUID, LIQUID-CRYSTALS, ORNSTEIN-ZERNIKE EQUATION, PHASE, SUBSTRATE, TRANSITIONS}, isbn = {0031-9007}, url = {://000221277900033}, author = {Sokolovska, T. G. and Sokolovskii, R. O. and Patey, G. N.} } @article {736, title = {Molecules that can{\textquoteright}t resist templation}, journal = {Chemical Communications}, number = {14}, year = {2003}, note = {ISI Document Delivery No.: 696EETimes Cited: 26Cited Reference Count: 47}, pages = {1617-1623}, type = {Article}, abstract = {The encapsulation of molecules or ions has captured the interest of a variety of researches, including those using zeolites, fullerenes, micelles, clathrates, and metal coordination complexes. Multiple hemispherical units have been used to create organic cages that can bind guests reversibly or irreversibly. Often such cages will only form in the presence of a guest, which acts as a template. This article summarizes some of the work in this field.}, keywords = {CAPSULES, CARCEPLEXES, CAVITANDS, CONTAINER COMPOUNDS, CRYSTAL-STRUCTURE, HEMICARCEPLEXES, HOST-GUEST COMPLEXATION, PHASE, REVERSIBLE ENCAPSULATION, SHELL CLOSURE}, isbn = {1359-7345}, url = {://000183872700002}, author = {Sherman, J.} } @article {453, title = {Dielectric relaxation of chained ferrofluids}, journal = {Journal of Chemical Physics}, volume = {116}, number = {15}, year = {2002}, note = {ISI Document Delivery No.: 537PGTimes Cited: 13Cited Reference Count: 18}, month = {Apr}, pages = {6731-6737}, type = {Article}, abstract = {Molecular and Brownian dynamics simulations are used to investigate the frequency-dependent dielectric relaxation of ferrofluids, with the objective of identifying features characteristic of dipolar chain formation at low densities. It is shown that the presence of chains gives rise to a high frequency band associated with the vibrational motion of dipoles within the chains. This band serves as a "signature" of association and is not present in dipolar fluids at higher, liquid-like densities. A simple theory that traps the basic features of the relaxation behavior is also presented. (C) 2002 American Institute of Physics.}, keywords = {FLUIDS, PHASE, SCATTERING, SIMULATION, SPHERES}, isbn = {0021-9606}, url = {://000174767200039}, author = {Murashov, V. V. and Camp, P. J. and Patey, G. N.} } @article {5219, title = {Binding of small alcohols to a lipid bilayer membrane: does the partitioning coefficient express the net affinity?}, journal = {Biophysical Chemistry}, volume = {89}, number = {1}, year = {2001}, note = {ISI Document Delivery No.: 397WQTimes Cited: 13Cited Reference Count: 55}, month = {Jan}, pages = {53-63}, type = {Article}, abstract = {The total vapor pressures at 26 degreesC of binary (water-alcohol) and ternary (water-alcohol-vesicle) systems were measured for sis short chain alcohols. The vesicles were unilamellar dipalmitoyl phosphatidylcholine (DMPC). The data was used to evaluate the effect of vesicles on the chemical potential of alcohols expressed as the preferential binding parameter of the alcohol-lipid interaction, Gamma (23). This quantity is a thermodynamic (model-free) measure of the net strength of membrane-alcohol interactions. For the smaller investigated alcohols (methanol, ethanol and 1-propanol) Gamma (23) was negative. This is indicative of so-called preferential hydration, a condition where the affinity of the membrane for water is higher than the affinity for the alcohol. For the longer alcohols (1-butanol, 1-pentanol, 1-hexanol) Gamma (23) was positive and increasing with increasing chain length. This demonstrates preferential binding, i.e. enrichment of alcohol in the membrane and a concomitant depletion of the solute in the aqueous bulk. The measured values of Gamma (23) were compared to the number of alcohol-membrane contacts specified by partitioning coefficients from the literature. It was found that for the small alcohols the number of alcohol-membrane contacts is much larger than the number of preferentially bound solutes. This discrepancy, which is theoretically expected in cases of very weak binding, becomes less pronounced with increasing alcohol chain length, and when the partitioning coefficient exceeds approximately 3 on the molal scale (10(2) in mole fraction units) it vanishes. Based on this, relationships between structural and thermodynamic interpretations of membrana partitioning are discussed. (C) 2001 Elsevier Science B.V. All rights reserved.}, keywords = {energy of interaction, ETHANOL, free, lipid membranes, membrane partitioning, MODEL, NONELECTROLYTE PARTITION, PHASE, PHOSPHATIDYLCHOLINE, preferential binding, protein stability, SOLUTES, THERMODYNAMICS, vapor pressure, VAPOR-PRESSURE, WATER}, isbn = {0301-4622}, url = {://000166721200005}, author = {Westh, P. and Trandum, C. and Koga,Yoshikata} } @inbook {4841, title = {Macromolecular crowding and its consequences}, booktitle = {International Review of Cytology - a Survey of Cell Biology, Vol 192}, series = {International Review of Cytology-a Survey of Cell Biology}, volume = {192}, year = {2000}, note = {ISI Document Delivery No.: BP32STimes Cited: 19Cited Reference Count: 30Review525 B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 USA}, pages = {155-170}, publisher = {Academic Press Inc}, organization = {Academic Press Inc}, address = {San Diego}, keywords = {AQUEOUS-SOLUTIONS, CYTOPLASM, DIAGRAMS, Flory-Huggins theory, incompatibilty, PHASE, PHASE-SEPARATION, PROTEINS, scaled particle theory, THERMODYNAMIC INCOMPATIBILITY}, isbn = {0074-7696}, url = {://000084720600006}, author = {Johansson, H. O. and Brooks, D. E. and Haynes, C. A.} } @article {4945, title = {Multiple quantum and high-resolution NMR, molecular structure, and order parameters of partially oriented ortho and meta dimethyl-, dichloro-, and chloromethylbenzenes codissolved in nematic liquid crystals}, journal = {Journal of Magnetic Resonance}, volume = {144}, number = {1}, year = {2000}, note = {ISI Document Delivery No.: 313NCTimes Cited: 18Cited Reference Count: 62}, month = {May}, pages = {58-73}, type = {Article}, abstract = {We develop a strategy for analyzing complex nuclear magnetic resonance (NMR) spectra of several solutes codissolved in liquid-crystal phases. Spectral parameters of solutes m- or o-xylene were estimated by analyzing 2D multiple-quantum NMR spectra using a modified version of a least-squares fitting routine which adjusts chemical shifts, order parameters, structural parameters, and/or dipolar couplings independently. These estimates were used to facilitate analysis of the high-resolution spectra which contain resonances from many solutes. Calculated spectra of m- or o-xylene were subtracted from the experimental high-resolution spectra leaving resonances from the other solutes readily visible, Accurate spectral parameters of all codissolved solutes were determined from the high-resolution spectra. Order parameters and structural parameters (including vibrationally corrected parameters) of m- and o-xylene, m- and o-chlorotoluene, and m- and o-dichlorobenzene were calculated from the dipolar couplings. (C) 2000 Academic Press.}, keywords = {ELECTRIC-DIPOLE INTERACTIONS, EXCITATION, INTERNAL-ROTATION, NUCLEAR-MAGNETIC-RESONANCE, orientational order, PHASE, POTENTIALS, SELECTIVE, SOLUTES, SOLVENTS, TRANSITIONS}, isbn = {1090-7807}, url = {://000087004900008}, author = {Syvitski, R. T. and Burnell, E. E.} } @article {4198, title = {Gas-liquid coexistence and demixing in systems with highly directional pair potentials}, journal = {Physical Review E}, volume = {57}, number = {5}, year = {1998}, note = {ISI Document Delivery No.: ZP583Times Cited: 19Cited Reference Count: 21Part B}, month = {May}, pages = {5682-5686}, type = {Article}, abstract = {Recent computer simulation studies strongly indicate that fluids of dipolar hard spheres do not display gas-isotropic liquid coexistence. In this paper we discuss a second example that also exhibits this rather unexpected behavior. This is a simple liquid-crystal model that we explore employing Gibbs ensemble Monte Carlo (GEMC) methods. It is shown that the system has clear gas-nematic liquid coexistence, but that the gas-isotropic liquid coexistence line is completely missing from the phase diagram. We attribute this to the highly directional nature of the attractive potential and argue that similar considerations are likely of relevance in the dipolar hard-sphere case as well. We also use GEMC techniques to investigate demixing in binary mixtures of neutral and dipolar hard spheres. For similar mixtures of neutral and charged have spheres, it is known that demixing is essentially condensation of the Coulombic fluid weakly influenced by the background of neutral hard spheres. Therefore, given that dipolar hard spheres do not condense, whether or not the present mixtures demix is an interesting question. In fact, demi?ring is observed and, moreover, the transition temperatures are in reasonable agreement with those predicted by the same integral equation theories that incorrectly predict condensation of the pure dipolar fluid. The critical temperature decreases rapidly with decreasing diameter of the neutral species consistent with the lack of gas-isotropic liquid coexistence for pure dipolar hard spheres. Clearly, for the present model demixing and dipolar condensation are not closely related phenomena as they are in the Coulombic systems. The neutral species appears to reduce the formation of dipolar "chains" or "clusters" that inhibit condensation of the purl dipolar hard-sphere fluid.}, keywords = {COMPUTER-SIMULATION, CRYSTAL MODELS, DIPOLAR HARD-SPHERES, FLUID, GIBBS ENSEMBLE, INSTABILITY, MIXTURE, MONTE-CARLO, orientational order, PHASE}, isbn = {1063-651X}, url = {://000073768000025}, author = {Blair, M. J. and Patey, G. N.} } @article {4351, title = {Water-soluble cavitands: Synthesis of methylene-bridged resorcin[4]arenes containing hydroxyls and phosphates at their feet and bromomethyls and thiomethyls at their rims}, journal = {Journal of Organic Chemistry}, volume = {63}, number = {20}, year = {1998}, note = {ISI Document Delivery No.: 127ZGTimes Cited: 11Cited Reference Count: 31}, month = {Oct}, pages = {6824-6829}, type = {Article}, abstract = {The synthesis of rim-functionalized methylene-bridged resorcin[4]arenes ("cavitands") containing hydrophilic propanol or water-solublilizing propylphosphate feet is described. The cavitands possess the synthetically useful benzylthiol (cavitands 6 and 16) or benzylbromide (cavitands 9 and 11) functionalities at their rims, which are suitable for further derivatization near the hydrophobic cavity of the cavitand. These water-soluble cavitands represent new building blocks that are ideal for use in aqueous supramolecular chemistry. As an example of their synthetic utility in supramolecular studies, we have reacted phosphate-footed cavitands 11 and 16 with cysteine-containing peptide 17 and chloroacetylated peptide 19, respectively, to afford the corresponding de novo proteins 18 and 20.}, keywords = {ADSORPTION, BUILDING-BLOCKS, CARCERANDS, ENCAPSULATION, HOST-GUEST COMPLEXATION, MOLECULAR, PHASE, RECOGNITION, RESORCINARENES, SELF-ASSEMBLED MONOLAYERS}, isbn = {0022-3263}, url = {://000076380300019}, author = {Mezo, A. R. and Sherman, J. C.} } @article {4095, title = {Addition reactions and longitudinal field spin relaxation of small radicals in gases: Mu+CO and Mu+N2O}, journal = {Hyperfine Interactions}, volume = {106}, number = {1-4}, year = {1997}, note = {ISI Document Delivery No.: XB055Times Cited: 4Cited Reference Count: 297th International Conference on Muon Spin Rotation, Relaxation, ResonanceAPR 15-19, 1996NIKKO, JAPANUniv Tokyo, Meson Sci Lab, Inst Phys \& Chem Res, Muon Sci Lab}, pages = {181-186}, type = {Proceedings Paper}, abstract = {Muon spin relaxation has been measured in longitudinal magnetic fields for Mu + CO and Mu + N2O reactions. The interpretation of the results for these small molecules, which are quite different than those obtained in larger molecule systems (e.g., Mu-ethyl and Mu-t-butyl radicals), are made with the phenomenological model for Mu-radical spin relaxation previously proposed. Proper fitting procedures are important in these cases and are discussed in the present paper.}, keywords = {DEPENDENCE, DYNAMICS, EXCHANGE, HYPERFINE COUPLING-CONSTANTS, PHASE, RESONANCE}, isbn = {0304-3843}, url = {://A1997XB05500026}, author = {Pan, J. J. and Arseneau, D. J. and Senba, M. and Shelley, M. and Fleming, Donald G.} } @article {3851, title = {Ferintoic acids A and B, new cyclic hexapeptides from the freshwater cyanobacterium Microcystis aeruginosa}, journal = {Journal of Natural Products}, volume = {59}, number = {6}, year = {1996}, note = {ISI Document Delivery No.: UT658Times Cited: 23Cited Reference Count: 30}, month = {Jun}, pages = {570-575}, type = {Article}, abstract = {The cyclic hexapeptides ferintoic acids A (1) and B (2) have been isolated from cells of Microcystis aeruginosa harvested during a natural bloom of the toxic cyanobacterium. The structures of 1 and 2 were determined by a combination of spectroscopic analysis and chemical degradation.}, keywords = {AMINO-ACIDS, BLUE-GREEN-ALGA, INHIBITOR, LR, PEPTIDE, PHASE, PROTEIN PHOSPHATASES, SPONGE THEONELLA SP, TOXIN}, isbn = {0163-3864}, url = {://A1996UT65800004}, author = {Williams, D. E. and Craig, M. and Holmes, C. F. B. and Andersen, R. J.} } @article {3596, title = {Ferroelectric order in model discotic nematic liquid crystals}, journal = {Physical Review Letters}, volume = {76}, number = {2}, year = {1996}, note = {ISI Document Delivery No.: TN761Times Cited: 31Cited Reference Count: 12}, month = {Jan}, pages = {239-242}, type = {Article}, abstract = {Monte Carlo calculations are used to examine orientational order in fluids of disk-shape particles with embedded dipoles. The dipoles are distributed over a circular {\textquoteright}{\textquoteright}patch{\textquoteright}{\textquoteright} of finite size. It is shown that such systems may undergo spontaneous polarization to form a stable ferroelectric discotic nematic phase.}, keywords = {COMPUTER-SIMULATION, ELECTROSTATIC SYSTEMS, MONTE-CARLO, orientational order, PERIODIC BOUNDARY-CONDITIONS, PHASE}, isbn = {0031-9007}, url = {://A1996TN76100021}, author = {Ayton, G. and Patey, G. N.} } @article {3801, title = {Monte Carlo simulations of orientational ordering of solutes in a nematic solvent: Comparison with mean-field models}, journal = {Molecular Physics}, volume = {88}, number = {3}, year = {1996}, note = {ISI Document Delivery No.: UT951Times Cited: 16Cited Reference Count: 23}, month = {Jun}, pages = {767-782}, type = {Article}, abstract = {Monte Carlo simulations were used to study orientational ordering of solutes in a nematic phase. Nematogens were modelled as hard prolate ellipsoids with an axis ratio of 5:1. Solutes were also modelled as hard prolate ellipsoids, with a variety of sizes and shape anisotropies. Solute order parameters and singlet orientational distribution functions were analysed using several mean-field models. The results confirm that these empirical mean-field potentials are closely linked to the anisotropic short-range repulsive forces that are crucial for the formation of the nematic phase.}, keywords = {ANISOTROPIC SYSTEMS, COMPUTER-SIMULATION, ELECTRIC-DIPOLE INTERACTIONS, LIQUID-CRYSTALS, MOLECULES, NEMATOGEN, PHASE, POTENTIALS, SIZE}, isbn = {0026-8976}, url = {://A1996UT95100015}, author = {Polson, J. M. and Burnell, E. E.} } @article {3497, title = {FREQUENCY-SELECTIVE EXCITATION IN MULTIPLE-QUANTUM NMR}, journal = {Journal of Magnetic Resonance Series A}, volume = {112}, number = {1}, year = {1995}, note = {ISI Document Delivery No.: QD079Times Cited: 18Cited Reference Count: 20}, month = {Jan}, pages = {1-6}, type = {Article}, abstract = {Orientation of molecules in liquid-crystalline solvents is a powerful tool for the study of molecular structure and orientation. However, the NMR spectra arising from even relatively small molecules oriented in such solvents can be so complex as to defy analysis. There is demonstrated here a frequency-selective modification of the basic multiple-quantum NMR experiment which is capable of measuring otherwise difficult-to-obtain information in favorable spin systems. (C) 1995 Academic Press, Inc.}, keywords = {AUTOMATED-ANALYSIS, FORMALISM, MOLECULAR-STRUCTURE, nematic, PHASE, PULSE EXPERIMENTS, SOLVENTS, SPECTRA, SPECTROSCOPY}, isbn = {1064-1858}, url = {://A1995QD07900001}, author = {Rendell, J. C. T. and Burnell, E. E.} } @article {3270, title = {AN ORIENTATIONAL STUDY OF SMALL SOLUTES IN ZERO ELECTRIC-FIELD GRADIENT NEMATIC LIQUID-CRYSTAL MIXTURES}, journal = {Journal of Physical Chemistry}, volume = {99}, number = {18}, year = {1995}, note = {ISI Document Delivery No.: QW705Times Cited: 2Cited Reference Count: 32}, month = {May}, pages = {7054-7059}, type = {Article}, abstract = {The solutes m-dichlorobenzene, o-dichlorobenzene. p-dichlorobenzene, o-dicyanzene, furan, tetrathiofulvalene, and fluorobenzene are studied in the zero electric field gradient mixtures 56.5 wt \% 1132/EBBA and 70 wt \% 5CB/EBBA using proton NMR. The two second-rank-order parameters obtained for each solute from analysis of the NMR spectra indicate that the solutes experience a similar anisotropic potential in both mixtures. The results are interpreted in terms of two models for the short-range anisotropic potential experienced by the solutes.}, keywords = {ALKYL CHAINS, BEHAVIOR, DIPOLE INTERACTIONS, MEAN TORQUE, MOLECULES, PHASE, POTENTIALS, SHAPE, SIZE, SOLVENTS}, isbn = {0022-3654}, url = {://A1995QW70500043}, author = {Chandrakumar, T. and Smith, L. and Burnell, E. E.} } @article {3116, title = {ETCHING OF GAAS (100) WITH GASEOUS H/CH3 MIXTURES}, journal = {International Journal of Chemical Kinetics}, volume = {26}, number = {1}, year = {1994}, note = {ISI Document Delivery No.: MN684Times Cited: 2Cited Reference Count: 18}, month = {Jan}, pages = {131-140}, type = {Article}, abstract = {GaAs (100) wafers were etched in mixtures of hydrogen atoms and methyl radicals. The atoms were formed in a remote hydrogen plasma, and a fraction of these were converted into methyl radicals by introducing methane into the flow system upstream from the semiconductor surface. The flux of hydrogen atoms into the reaction chamber was determined by isothermal calorimetry. The methyl radical nux passing over the substrate was then calculated using previously determined rate parameters for the reaction between atomic hydrogen and methane, and a simple modeling program. The GaAs etch rates were about an order of magnitude faster when methyl radicals were present in the hydrogen atom stream, and were found to follow a first-order dependence on the partial pressure of methyl radicals. Absolute rate constants were determined and an Arrhenius activation energy of 1.2 kcal mol(-1) was calculated. The values of k and E(alpha), are consistent with a diffusion-controlled process. SEM photographs of the surface revealed small crystallographic features that made the surface appear very rough. XPS analysis indicated that these surfaces were arsenic deficient. A mechanism is proposed for the etching of GaAs by a combination of methyl radicals and hydrogen atoms. (C) 1994 John Wiley and Sans, Inc.}, keywords = {PHASE, REACTION-MECHANISMS}, isbn = {0538-8066}, url = {://A1994MN68400011}, author = {Meharg, P. F. A. and Ogryzlo, E. A.} } @article {3184, title = {STABILITY OF BINARY-MIXTURES - SUPERSATURATION LIMITS OF AQUEOUS ALKALI-HALIDE SOLUTIONS}, journal = {Journal of Chemical Physics}, volume = {100}, number = {5}, year = {1994}, note = {ISI Document Delivery No.: MY349Times Cited: 20Cited Reference Count: 38}, month = {Mar}, pages = {3827-3842}, type = {Article}, abstract = {The stability of ionic binary mixtures is investigated by an integral equation method. In presenting the theory a distinction is made between primary and secondary stability criteria, and this distinction is used to clarify some misconceptions in the literature. The derived stability criteria are then applied to electrolyte solutions as well as to a simple binary mixture. In a simple mixture of hard spheres in wafer, both mechanical and material instabilities are found near the spinodal line along with evidence of long-range hydrophobic forces. Results for the electrolyte solutions indicate that salts with only large ions, such as CsI, and those with a smaller ion, such as Na+ or K+, behave differently near the spinodal line. CsI acts hydrophobicly, and appears to undergo demixing from the solvent, whereas NaCl and KCl, which bind the solvent more tightly, do not show clear signs of any such demixing, but do appear to become mechanically unstable. Finally, some recent results of Chen and Forstmann [J. Chem; Phys. 97, 3696 (1992)] are discussed and applied to the present systems.}, keywords = {DIPOLAR, ELECTROLYTE-SOLUTIONS, equation, FLUID MIXTURES, HYPERNETTED-CHAIN APPROXIMATION, INSTABILITY, NEUTRAL HARD-SPHERES, PHASE, SEPARATION, SPINODAL CURVE}, isbn = {0021-9606}, url = {://A1994MY34900047}, author = {Ursenbach, C. P. and Patey, G. N.} } @article {3187, title = {TENSER LEED ANALYSIS OF THE PD(100)-(ROOT-5X-ROOT-5)R27-DEGREES-O SURFACE-STRUCTURE}, journal = {Surface Science}, volume = {318}, number = {1-2}, year = {1994}, note = {ISI Document Delivery No.: PL286Times Cited: 29Cited Reference Count: 29}, month = {Oct}, pages = {129-138}, type = {Article}, abstract = {A tenser LEED analysis of the Pd(100)-(root 5 x root 5)R27 degrees-O surface structure supports a surface oxide model, as first postulated by Orent and Bader. The detailed model which gives the best correspondence with experimental intensity data has a PdO(001) overlayer stacked on to the Pd(100) surface such that rumpling is induced in both the oxide and topmost Pd(100) layers. The structure can be seen as representing a compromise between the drive toward an ideally flat PdO(001) surface and the need to optimize total bonding at the surface. Pd atoms in the topmost Pd(100) layer appear to displace laterally to minimize corrugations in the top metal layers. The total corrugations in the PdO overlayer and the first Pd(100) layer are indicated to be about 0.26 and 0.51 Angstrom, respectively. The average O-Pd bond length for two-coordinate O on the Pd surface (1.73 Angstrom) remains dose to the predicted value of 1.76 Angstrom based on the structure of bulk PdO.}, keywords = {ADSORPTION, desorption, ENERGY-ELECTRON-DIFFRACTION, HYDROGEN, OXYGEN, PD(100) SURFACE, PHASE, RECONSTRUCTION}, isbn = {0039-6028}, url = {://A1994PL28600019}, author = {Vu, D. T. and Mitchell, K. A. R. and Warren, O. L. and Thiel, P. A.} } @article {7119, title = {THE CONFORMATION OF 2,2{\textquoteright}-DITHIOPHENE IN NEMATIC SOLVENTS DETERMINED BY H-1-NMR}, journal = {Molecular Physics}, volume = {74}, number = {5}, year = {1991}, note = {ISI Document Delivery No.: GY085Times Cited: 24Cited Reference Count: 26}, month = {Dec}, pages = {1027-1035}, type = {Article}, abstract = {In this paper we report a determination of the structure 2,2{\textquoteright}-dithiophene dissolved in different nematic liquid crystal solvents. The H-1-NMR spectra of this molecule dissolved in a 55\% Merck ZLI 1132/45\% N-(4-ethoxybenzylidene)-4{\textquoteright}-n-butylaniline (w/w) mixture are recorded at 300 and 304 K and are analysed. The dipolar coupling constants obtained are used to show that the solute molecule exists in both the s-cis and the s-trans conformations. The s-trans conformer is planar and the absolute value of the dihedral angle-PHI between the two thiophene ring planes for the s-cis conformer is found to be (24 +/- 1)degrees. Using the same method of analysis we reinterpreted two additional independent sets of published dipolar coupling constants from H-1-NMR spectra of 2,2{\textquoteright}-dithiophene dissolved in Merck Phase IV at room temperature and in 80\% N-(4-ethoxybenzylidene)-4{\textquoteright}-n-butylaniline/20\% O-carbobutoxy-4-oxybenzoic acid ethoxy phenyl ester at 301 K. These additional studies yield the same results for the structure of 2,2{\textquoteright}-dithiophene. We also estimate that in each of the three nematic solvents (61 +/- 3)\% of the solute 2,2{\textquoteright}-dithiophene exists in the s-trans state.}, keywords = {2, 2{\textquoteright}-BITHIENYL, BARRIER, LIQUID-CRYSTALS, MOLECULES, orientational order, PHASE, SIZE, SOLUTES}, isbn = {0026-8976}, url = {://A1991GY08500007}, author = {ter Beek, L. C. and Zimmerman, D. S. and Burnell, E. E.} }