@article {2390, title = {Effect of Membrane Composition on Antimicrobial Peptides Aurein 2.2 and 2.3 From Australian Southern Bell Frogs}, journal = {Biophysical Journal}, volume = {96}, number = {2}, year = {2009}, note = {ISI Document Delivery No.: 450BYTimes Cited: 8Cited Reference Count: 96Cheng, John T. J. Hale, John D. Elliot, Melissa Hancock, Robert E. W. Straus, Suzana K.}, month = {Jan}, pages = {552-565}, type = {Article}, abstract = {The effects of hydrophobic thickness and the molar phosphatidylglycerol (PG) content of lipid bilayers on the structure and membrane interaction of three cationic antimicrobial peptides were examined: aurein 2.2, aurein 2.3 (almost identical to aurein 2.2, except for a point mutation at residue 13), and a carboxy C-terminal analog of aurein 2.3. Circular dichroism results indicated that all three peptides adopt an a-helical structure in the presence of a 3:1 molar mixture of 1,2-dimyristoyi-sn-glycero3-phosphocholine/1,2-dimyristoyi-sn-glycero-3- [phospho-rac-(1-glycerol)] (DMPC/DMPG), and 1:1 and 3:1 molar mixtures of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine/1-paimitoyl-2-oleoyl-sn -glycero-3-[phospho-rac-(1-glycerol)] (POPC/POPG). Oriented circular dichroism data for three different lipid compositions showed that all three peptides were surface-adsorbed at low peptide concentrations, but were inserted into the membrane at higher peptide concentrations. The (31)p solid-state NMR data of the three peptides in the DMPC/DMPG and POPC/POPG bilayers showed that all three peptides significantly perturbed lipid headgroups, in a peptide or lipid composition-dependent manner. Differential scanning calorimetry results demonstrated that both amidated aurein peptides perturbed the overall phase structure of DMPC/DMPG bilayers, but perturbed the POPC/POPG chains less. The nature of the perturbation of DMPC/DMPG bilayers was most likely micellization, and for the POPC/POPG bilayers, distorted toroidal pores or localized membrane aggregate formation. Calcein release assay results showed that aurein peptide-induced membrane leakage was more severe in DMPC/DMPG liposomes than in POPC/POPG liposomes, and that aurein 2.2 induced higher calcein release than aurein 2.3 and aurein 2.3-COOH from 1:1 and 3:1 POPC/POPG liposomes. Finally, DiSC(3)5 assay data further delineated aurein 2.2 from the others by showing that it perturbed the lipid membranes of intact S. aureus C622 most efficiently, whereas aurein 2.3 had the same efficiency as gramicidin S, and aurein 2.3-COOH was the least efficient. Taken together, these data show that the membrane interactions of aurein peptides are affected by the hydrophobic thickness of the lipid bilayers and the PG content.}, keywords = {ANTIBIOTIC PEPTIDES, CIRCULAR-DICHROISM SPECTROSCOPY, HOST-DEFENSE PEPTIDES, LIPID-COMPOSITION, MEMBRANES, MODEL, PHOSPHOLIPID-BILAYER MEMBRANES, PROTEIN SECONDARY STRUCTURE, SOLID-STATE NMR, STAPHYLOCOCCUS-AUREUS, TREE-FROG}, isbn = {0006-3495}, url = {://000266377200025}, author = {Cheng, J. T. J. and Hale, J. D. and Elliot, M. and Hancock, R. E. W. and Straus, S. K.} } @article {2649, title = {Free Energy Barrier Estimation for the Dissociation of Charged Protein Complexes in the Gas Phase}, journal = {Journal of Physical Chemistry A}, volume = {113}, number = {16}, year = {2009}, note = {ISI Document Delivery No.: 435ZUTimes Cited: 4Cited Reference Count: 29Wanasundara, Surajith N. Thachuk, Mark}, month = {Apr}, pages = {3814-3821}, type = {Article}, abstract = {Free energies are calculated for the protonated cytochrome c{\textquoteright} dimer ion in the gas phase as a function of the center of mass distance between the monomers. A number of different charge partitionings are examined as well as the behavior of the neutral complex. It is found that monomer unfolding competes with complex dissociation and that the relative importance of these two factors depends upon the charge partitioning in the complex. Symmetric charge partitionings preferentially suppress the dissociation barrier relative to unfolding, and complexes tend to dissociate promptly with little structural changes occurring in the monomers. Alternatively, asymmetric charge partitionings preferentially lower the barrier for monomer unfolding relative to the dissociation barrier. In this case, the monomer with the higher charge unfolds before the complex dissociates. For the homodimer considered here, this pathway has a large free energy barrier. The results can be rationalized using schematic two-dimensional free energy surfaces. Additionally, for large multimeric complexes, it is argued that the unfolding and subsequent charging of a single monomer is a favorable process, cooperatively lowering both the unfolding and dissociation barriers at the same time.}, keywords = {ASSEMBLIES, ELECTROSPRAY-IONIZATION, MASS-SPECTROMETRY, MODEL, MOLECULAR-DYNAMICS, ORIGIN, PATHWAYS, SIMULATIONS, SYSTEMS, THERMAL-DISSOCIATION}, isbn = {1089-5639}, url = {://000265383200014}, author = {Wanasundara, S. N. and Thachuk, M.} } @article {2473, title = {Poly(oligo(ethylene glycol)acrylamide) Brushes by Surface Initiated Polymerization: Effect of Macromonomer Chain Length on Brush Growth and Protein Adsorption from Blood Plasma}, journal = {Langmuir}, volume = {25}, number = {6}, year = {2009}, note = {ISI Document Delivery No.: 418JRTimes Cited: 12Cited Reference Count: 45Kizhakkedathu, Jayachandran N. Janzen, Johan Le, Yevgeniya Kainthan, Rajesh K. Brooks, Donald E.}, month = {Mar}, pages = {3794-3801}, type = {Article}, abstract = {Three hydrolytically stable polyethyleneglycol (PEG)-based N-substituted acrylamide macromonomers, methoxypolyethyleneglycol (350) acrylamide (MPEG(350)Am) methoxypolyethyleneglycol (750) acrylamide(MPEG(750)Am) and methoxypolyethyleneglycol (2000)acrylamide (MPEG(2000)Am) with increasing PEG chain length were synthesized. Surface-initiated aqueous atom transfer radical polymerization (ATRP) using CuCl/1,1,4,7,10,10-hexamethyl triethylene tetramine (HMTETA) catalyst was utilized to generate dense polymer brushes from these monomers via an ester linker group on the surface of model polystyrene (PS) particles. The molecular weight, hydrodynamic thickness, and graft densities of the grafted polymer layers were controlled by changing the reaction parameters of monomer concentration, addition of Cu(II)Cl-2, and sodium chloride. The graft densities of surface-grafted brushes decreased with increasing PEG macromonomer chain length, 350 > 750 >> 2000, under similar experimental conditions. The molecular weight of grafts increased with increase in monomer concentration, and only selected conditions produced narrow distributed polymer chains. The molecular weight of grafted polymer chains differs significantly to those formed in solution. The hydrodynamic thicknesses of the grafted polymer layers were fitted to the Daoud and Cotton model (DCM) for brush height on spherical surfaces. The results show that the size of the pendent groups on the polymer chains has a profound effect on the hydrodynamic thickness of the brush for a given degree of polymerization. The new PEG-based surfaces show good protection against nonspecific protein adsorption from blood plasma compared to the bare surface. Protein adsorption decreased with increasing surface density of grafted polymer chains. Poly(MPEG(750)Am) brushes were more effective in preventing protein adsorption than poly(MPEG(350)Am) even at low graft densities, presumably due to the increase in PEG content in the grafted layer.}, keywords = {AQUEOUS ATRP, COPOLYMER BRUSHES, density, METHYL-METHACRYLATE, MODEL, N-DIMETHYLACRYLAMIDE), OLIGO(ETHYLENE GLYCOL) METHACRYLATE, PHOSPHORYLCHOLINE, POLY(N, POLYMERS, TRANSFER RADICAL POLYMERIZATION}, isbn = {0743-7463}, url = {://000264145000068}, author = {Kizhakkedathu, J. N. and Janzen, J. and Le, Y. and Kainthan, R. K. and Brooks, D. E.} } @article {2553, title = {Pseudospectral method of solution of the Fitzhugh-Nagumo equation}, journal = {Mathematics and Computers in Simulation}, volume = {79}, number = {7}, year = {2009}, note = {ISI Document Delivery No.: 429KBTimes Cited: 3Cited Reference Count: 41Olmos, Daniel Shizgal, Bernie D.}, month = {Mar}, pages = {2258-2278}, type = {Article}, abstract = {We present a study of the convergence of different numerical schemes in the solution of the Fitzhugh-Nagumo equations in the form of two coupled reaction diffusion equations for activator and inhibitor variables. The diffusion coefficient for the inhibitor is taken to be zero. The Fitzhugh-Nagumo equations, have spatial and temporal dynamics in two different scales and the solutions exhibit shock-like waves. The numerical schemes employed are a Chebyshev multidomain method, a finite difference method and the method developed by Barkley [D. Barkley, A model for fast computer simulation of excitable media, Physica D, 49 (1991) 61-70]. We consider two different models for the local dynamics. We present results for plane wave propagation in one dimension and spiral waves for two dimensions. We use an operator splitting method with the Chebyshev multidomain approach in order to reduce the computational time. Zero flux boundary conditions are imposed on the solutions. (C) 2009 IMACS. Published by Elsevier B.V. All rights reserved.}, keywords = {3-DIMENSIONAL EXCITABLE MEDIA, Chebyshev multidomain, Convergence, DYNAMICS, Fitzhugh-Nagumo equations, MECHANISM, MODEL, REACTION-DIFFUSION-SYSTEMS, SELECTION, Spiral waves, SPIRAL-WAVE, TRANSITION}, isbn = {0378-4754}, url = {://000264918200021}, author = {Olmos, D. and Shizgal, B. D.} } @article {2175, title = {Gas-phase proton-transfer pathways in protonated histidylglycine}, journal = {Rapid Communications in Mass Spectrometry}, volume = {22}, number = {18}, year = {2008}, note = {ISI Document Delivery No.: 355WATimes Cited: 2Cited Reference Count: 23MacDonald, Brandon I. Thachuk, Mark}, month = {Sep}, pages = {2946-2954}, type = {Article}, abstract = {Pathways for proton transfer in the histidylglycine cation are examined in the gas-phase environment with the goal of understanding the mechanism by which protons may become mobile in proteins with basic amino acid residues. An extensive search of the potential energy surface is performed using density functional theory (DFT) methods. After corrections for zero-point energy are included, it is found that all the lowest energy barriers for proton transfer between the N-terminus and the imidazole ring have heights of only a few kcal/mol, while those between the imidazole ring and the backbone amide oxygen have heights of approximately 15 kcal/mol when the proton is moving from the ring to the backbone and only a few kcal/mol when moving from the backbone to the imidazole ring. In mass spectrometric techniques employing collision-induced dissociation to dissociate protein complex ions or to fragment peptides, these barriers can be overcome, and the protons mobilized. Copyright (C) 2008 John Wiley \& Sons, Ltd.}, keywords = {COLLISION-INDUCED DISSOCIATION, fragmentation, IONIZATION, MASS-SPECTROMETRY, mobility, MODEL, ORIGIN, PEPTIDE IONS}, isbn = {0951-4198}, url = {://000259738700023}, author = {MacDonald, B. I. and Thachuk, M.} } @article {2203, title = {Sound dispersion in single-component systems}, journal = {Physica a-Statistical Mechanics and Its Applications}, volume = {387}, number = {16-17}, year = {2008}, note = {ISI Document Delivery No.: 312TETimes Cited: 0Cited Reference Count: 46Napier, Duncan G. Shizgal, Bernie D.}, month = {Jul}, pages = {4099-4118}, type = {Article}, abstract = {The present paper considers the theoretical description of the propagation of sound waves in a one component monatomic gas. The interatomic potential is assumed to vary as the inverse fourth power of the interatomic separation, that is for so-called Maxwell molecules. The eigenvalues and eigenfunctions of the linearized Boltzmann collision operator are known for this model. We emphasize the behaviour of this system in the rarefied, large Knudsen number regime for which the convergence of solutions of the Boltzmann equation can be very slow. We carry out a detailed comparison of the previous formalisms by Wang Chang and Uhlenbeck [C.S. Wang Chang, G.E. Uhlenbeck, The kinetic theory of gases, in: G.E. Uhlenbeck, De Boer, (Eds.), Studies in Statistical Mechanics, vol. 5, Elsevier, New York, 1970, pp. 43-75], Alexeev [B.V. Alexeev, Philos. Trans. R. Soc. A 349 (1994) 357] and Sirovich and Thurber [L. Sirovich, J. K. Thurber, J. Math. Phys. 10 (1969) 239]. The latter exploit a general method of solution of the Boltzmann equation developed by Gross and Jackson. We demonstrate that the Generalized Boltzmann Equation proposed by Alexeev is not appropriate and we show the reasoning for the success of the Sirovich Thurber approach over the Wang Chang and Uhlenbeck calculations. Comparisons are made with experimental data. (c) 2008 Elsevier B.V. All rights reserved.}, keywords = {BINARY GAS-MIXTURES, Boltzmann equation, BOLTZMANN-EQUATION, KINETIC THEORY, LIGHT-SCATTERING, Maxwell molecules, MODEL, MONATOMIC GASES, SLOW SOUND, sound dispersion, WAVE-PROPAGATION}, isbn = {0378-4371}, url = {://000256692900007}, author = {Napier, D. G. and Shizgal, B. D.} } @article {1374, title = {Monte Carlo simulations of the adsorption of CO2 on the MgO(100) surface}, journal = {Journal of Chemical Physics}, volume = {124}, number = {11}, year = {2006}, note = {ISI Document Delivery No.: 023XRTimes Cited: 10Cited Reference Count: 30}, month = {Mar}, pages = {9}, type = {Article}, abstract = {The adsorption of CO2 gas on the MgO (100) crystal surface is investigated using grand canonical Monte Carlo simulations. This allows us to obtain adsorption isotherms that can be compared with experiment, as well as to explore the possible formation of monolayers of different densities. Our model calculations agree reasonably well with the available experimental results. We find a {\textquoteright}{\textquoteright} low-density {\textquoteright}{\textquoteright} adsorbed monolayer where each CO2 molecule is bound to two Mg2+ ions on the MgO substrate. We also observe the formation of monolayers of higher density, where some of the CO2 molecules have rotated and tilted to expose additional binding sites. Low-temperature simulations of both the low- and high-density monolayers reveal that these states are very close in energy, with binding energies of approximately 7 kcal/mol at T=5 K. The high-density monolayer given by our model has a density that is significantly less than the reported experimental value. We discuss this discrepancy and offer suggestions for resolving it. (c) 2006 American Institute of Physics.}, keywords = {CARBON-DIOXIDE, DYNAMICS, LEED, MODEL, MONOLAYERS, SINGLE-CRYSTAL SURFACE, TRANSITION}, isbn = {0021-9606}, url = {://000236160000043}, author = {Daub, C. D. and Patey, G. N. and Jack, D. B. and Sallabi, A. K.} } @article {1526, title = {Viable plastics recycling from end-of-life electronics}, journal = {Ieee Transactions on Electronics Packaging Manufacturing}, volume = {29}, number = {1}, year = {2006}, note = {ISI Document Delivery No.: 010ALTimes Cited: 3Cited Reference Count: 62}, month = {Jan}, pages = {25-31}, type = {Article}, abstract = {Millions of end-of-life (EOL) electronic products represent more than one million tons of engineering thermoplastics. The economically and environmentally sound recovery of engineering thermoplastics from EOL electronics is a challenge to the sustainability of electronics manufacturing. In this paper, we review the technologies to separate and identify pure post-consumer plastics from EOL electronics, which are followed by the comparison of electronic plastics recycling processes and the network models for plastics recycling processes. We also review successful plastics recycling practices for electronics. In addition, further research directions for recycling plastics from EOL electronics are discussed.}, keywords = {DECISION-MAKING, DESIGN, disassembly, end-of-life (EOL) electronics, HIGH-IMPACT POLYSTYRENE, IDENTIFICATION, METHODOLOGY, MODEL, OPTIMIZATION, plastics, PRODUCT, RECOVERY, recycling, SELECTIVE FLOTATION SEPARATION, SEPARATION}, isbn = {1521-334X}, url = {://000235155100004}, author = {Qu, X. L. and Williams, J. A. S. and Grant, E. R.} } @article {1225, title = {Entropic interaction chromatography: Separating proteins on the basis of size using end-grafted polymer brushes}, journal = {Biotechnology and Bioengineering}, volume = {90}, number = {1}, year = {2005}, note = {ISI Document Delivery No.: 909ETTimes Cited: 9Cited Reference Count: 48}, month = {Apr}, pages = {1-13}, type = {Article}, abstract = {Partitioning of a macromolecule into the interfacial volume occupied by a grafted polymer brush decreases the configurational entropy (Delta S(c)brush) of the terminally attached linear polymer chains due to a loss of free volume. Self-consistent field theory (SCF) calculations are used to show that Delta S(c)brush is a strong function of both the size (MW,) of the partitioning macromolecule and the depth of penetration into the brush volume. We further demonstrate that the strong dependence of Delta S(c)brush on MW, provides a novel and powerful platform, which we call entropic interaction chromatography (EIC), for efficiently separating mixtures of proteins on the basis of size. Two EIC columns, differing primarily in polymer grafting density, were prepared by growing a brush of poly(methoxyethyl acrylamide) chains on the surface of a widepore (1,000-angstrom pores, 64-mu m diameter rigid beads) resin (Toyopearl AF-650M) bearing surface aldehyde groups. Semipreparative 0.1-L columns packed with either EIC resin provide reduced-plate heights of 2 or less for efficient separation of globular protein mixtures over at least three molecular-weight decades. Protein partitioning within these wide-pore EIC columns is shown to be effectively modeled as a thermodynamically controlled process, allowing partition coefficients (K-p) and elution chromatograms to be accurately predicted using a column model that combines SCF calculation of Kp values with an equilibrium-dispersion type model of solute transport through the column. This model is used to explore the dependence of column separation efficiency on brush properties, predicting that optimal separation of proteins over a broad MW, range is achieved at low to moderate grafting densities and intermediate chain lengths. (c) 2005 Wiley Periodicals, Inc.}, keywords = {ADSORPTION, CHAIN MOLECULES, CONSISTENT-FIELD THEORY, entropic interaction chromatography, equilibrium dispersion, EXCLUSION CHROMATOGRAPHY, GEL FILTRATION, grafted polymer brush, HUMAN SERUM-ALBUMIN, LIQUID-CHROMATOGRAPHY, MODEL, MOLECULAR-WEIGHT, MONTE-CARLO, protein purification, size exclusion chromatography, STATISTICAL-THEORY}, isbn = {0006-3592}, url = {://000227843800001}, author = {Pang, P. and Koska, J. and Coad, B. R. and Brooks, D. E. and Haynes, C. A.} } @article {1258, title = {Fluctuation functions in aqueous NaCl and urea}, journal = {Journal of Physical Chemistry B}, volume = {109}, number = {35}, year = {2005}, note = {ISI Document Delivery No.: 961UNTimes Cited: 4Cited Reference Count: 30}, month = {Sep}, pages = {16886-16890}, type = {Article}, abstract = {We earlier devised a set of fluctuation functions that provide relative qualitative differences of the amplitude (intensity) and the wavelength (extensity) of fluctuations in entropy and volume and the entropy-volume cross fluctuations. We discuss the mixing schemes in aqueous NaCl and urea using these fluctuation functions. Our earlier studies by using the second and third derivatives of Gibbs energy indicated that their effects on H2O are qualitatively different. An NaCl hydrates 7.5 molecules of H2O but leaves the bulk H2O away from the hydration shell unperturbed. Urea, on the other hand, connects onto the hydrogen bond network of H2O but retards the degree of fluctuation inherent in H2O. The behavior of the fluctuation functions calculated here are consistent with the above mixing schemes. Furthermore, urea was found to reduce the wavelength of fluctuation more strongly than NaCl.}, keywords = {25-DEGREES-C, H2O, LIQUID WATER, MODEL, PARTIAL MOLAR FLUCTUATIONS, PERCOLATION, SODIUM-CHLORIDE, SYSTEMS, VOLUMETRIC PROPERTIES}, isbn = {1520-6106}, url = {://000231687400045}, author = {Siu, D. and Koga,Yoshikata} } @article {1260, title = {Nematic fluid structure in wall-field geometry}, journal = {Journal of Chemical Physics}, volume = {122}, number = {3}, year = {2005}, note = {ISI Document Delivery No.: 893VPTimes Cited: 6Cited Reference Count: 31}, month = {Jan}, pages = {9}, type = {Article}, abstract = {We describe an integral equation method for obtaining the distribution of a nematic fluid near a wall and interacting with a uniform orienting field. Complete density-orientational profiles are calculated for a model nematic with different wall-particle interactions and different orientations of the wall with respect to the field. For orienting walls we identify particular long-range correlations that are responsible for reorientation of the bulk nematic at zero external field. These correlations become stronger as the wall-particle interaction is increased in range; they become longer ranged as the orienting field is weakened. Special attention is focused on systems where the wall-particle interaction favors orientations perpendicular to the surface. The local director orientation can vary discontinuously with the distance from the surface when the orienting influences of the field and the wall are antagonistic. At high densities smectic-like structures appear. Adsorption phenomena are also discussed. For inert hard walls, the ordered fluid avoids the surface, and a surface layer where the particles tend to orient perpendicular to the bulk director appears. Experimentally, this might be seen as wetting of the wall by a less-ordered fluid. (C) 2005 American Institute of Physics.}, keywords = {ALIGNMENT, APPROXIMATION, LIQUID-CRYSTALS, MODEL, ORNSTEIN-ZERNIKE EQUATION, PHASE-TRANSITION, SOLID SUBSTRATE, SUBSTRATE INTERFACE, SURFACE}, isbn = {0021-9606}, url = {://000226748800030}, author = {Sokolovska, T. G. and Sokolovskii, R. O. and Patey, G. N.} } @article {956, title = {Deliquescence and crystallization of ammonium sulfate particles internally mixed with water-soluble organic compounds}, journal = {Journal of Physical Chemistry A}, volume = {108}, number = {52}, year = {2004}, note = {ISI Document Delivery No.: 882FPTimes Cited: 38Cited Reference Count: 66}, month = {Dec}, pages = {11600-11608}, type = {Article}, abstract = {The deliquescence and crystallization of ammonium sulfate particles internally mixed with water-soluble organic material have been studied, restricted to an organic mass fraction of less than 0.6. The organic species used were malonic acid, glycerol, levoglucosan (1,6-anhydro-beta-D-glucopyranose), and Suwannee River fulvic acid. Our deliquescence results for systems with malonic acid and fulvic acid are in agreement with existing literature values. Glycerol deliquescence results are slightly lower than previous measurements. The levoglucosan results are the first of this kind. Total deliquescence relative humidities for the different systems are the same within the uncertainty of the measurements when the organic mole fraction is less than approximately 0.35. At an organic mole fraction of 0.6, the maximum deviation of total deliquescence relative humidities between the systems is approximately 10\% relative humidity. We show that thermodynamic calculations based on a simplified version of a model recently proposed by Clegg et al. (J. Aerosol Sci. 2001, 32, 713)1 are in agreement with measured values of deliquescence relative humidity up to an organic mole fraction of approximately 0.4 for most of the systems studied. The crystallization relative humidity (CRH) of mixed systems of ammonium sulfate with malonic acid, glycerol, or levoglucosan decreases significantly from the CRH of pure ammonium sulfate when the organic mole fraction is greater than about 0.25. This is in contrast to our previous study with glutaric acid where CRH remained close to CRH of pure ammonium sulfate up to a glutaric acid mole fraction of 0.4. CRH values are shown to vary depending on the type of,organic present. In terms of atmospheric implications, we estimate that organics, on average, are only a minor perturbation on the deliquescence relative humidity of the pure inorganic particles, whereas the organics, on average, may decrease the CRH of pure inorganic particles significantly and this effect depends on the type of organic material.}, keywords = {ATMOSPHERIC AEROSOL, BLACK CARBON, DICARBOXYLIC-ACIDS, FINE AEROSOL, HUMIC-LIKE SUBSTANCES, HYGROSCOPIC PROPERTIES, MODEL, PHASE-TRANSITIONS, PHYSICAL, RELATIVE-HUMIDITY, STATE}, isbn = {1089-5639}, url = {://000225924800016}, author = {Parsons, M. T. and Knopf, D. A. and Bertram, A. K.} } @article {1040, title = {Laser-light-scattering study of internal motions of polymer chains grafted on spherical latex particles}, journal = {Journal of Physical Chemistry B}, volume = {108}, number = {48}, year = {2004}, note = {ISI Document Delivery No.: 875JUTimes Cited: 6Cited Reference Count: 35}, month = {Dec}, pages = {18479-18484}, type = {Article}, abstract = {Using atom-transfer radical polymerization, we have prepared core-shell particles by grafting thermally sensitive poly(N-isopropylacrylamide) (PNIPAM) chains on a spherical polystyrene latex core (with a radius of similar to287 nm) via the "grafting-from" approach. As the temperature increases from 25 degreesC to 35 degreesC, the PNIPAM shell shrinks from a thickness of 625 nm to 110 nm and the chain density near the core increases from 7.3 x 10(-3) g/cm(3) to 7.2 x 10(-2) g/cm(3). Using such core-shell particles, we have, for the first time, been able to study dynamics of long chains anchored on a particle in dilute dispersion by laser-light scattering. Our results showed that, besides the translational diffusion of the particle as a whole, there also exists an additional slow relaxation mode that is only observable at larger scattering vectors (q),which are presumably related to internal motions of the shell. In the fully swollen state, the relaxation rate of the slow motion ((slow)) is insensitive to the observation length (1/q); however, its contribution to the scattering intensity (A(slow)) increases as q increases. In the shrunken state, (slow) slightly decreases as q increases. (slow) can be scaled to the shell thickness ((brush)) as (slow) proportional to (alpha)(brush), with alpha = -2.5 +/- 0.2, which is smaller than the predicated value of 3.}, keywords = {AQUEOUS ATRP, BRUSHES, CONFORMATION, DYNAMICS, GLOBULE TYPE TRANSITIONS, INTERFACE, LAYERS, MODEL, POLY(N-ISOPROPYLACRYLAMIDE), SIMULATION}, isbn = {1520-6106}, url = {://000225417200015}, author = {Yang, C. and Kizhakkedathu, J. N. and Brooks, D. E. and Jin, F. and Wu, C.} } @article {894, title = {Plasma protein adsorption to surfaces grafted with dense homopolymer and copolymer brushes containing poly(N-isopropylacrylamide)}, journal = {Journal of Biomaterials Science-Polymer Edition}, volume = {15}, number = {9}, year = {2004}, note = {ISI Document Delivery No.: 865ALTimes Cited: 13Cited Reference Count: 38Symposium on Gels, Genes, Grafts and Giants held in Celebration of the 70th Birthday of Allan HoffmanDEC, 2002Maui, HIUniv Washington Engineered Biomat NSF Engn Res Ctr}, pages = {1121-1135}, type = {Proceedings Paper}, abstract = {Growing polymer chains from surface initiators in principle allows much more dense polymer surface layers to be created than can be produced by grafting of whole (self-excluding) chains. We have utilized aqueous atom transfer radical polymerization to graft a series of cleavable hydrophilic poly (N-isopropylacrylamide) (PNIPAM) homopolymers and block copolymers of substituted acry-lamides from polystyrene latex to give brushes of controlled MW and surface density. Average chain separations much less than their free solution radii of gyration have been achieved. Exposure to radiolabeled single proteins or to whole plasma and subsequent analysis by SDS-PAGE shows that PNIPAM brushes decrease protein adsorption relative to the latex surface or other substituted polyacrylamides. The PNIPAM brushes exhibit a second-order phase transition around 30degreesC as reflected by a decrease in the hydrodynamic thickness of the brush at higher temperatures. Total plasma protein adsorption is increased at 40degreesC compared to 20degreesC but there is significant differential adsorption behavior among the proteins detected by gel-electrophoresis analysis.}, keywords = {ADSORPTION, BIOMATERIALS, block copolymer, CHROMATOGRAPHY, FIBRINOGEN ADSORPTION, grafted latex, I-125 radiolabel, MODEL, OXIDE), plasma protein, POLY(ETHYLENE GLYCOL), POLY(N-ISOPROPYLACRYLAMIDE), polymer brush, POLYMER BRUSHES, PREVENTION, SDS-PAGE, SELF-ASSEMBLED MONOLAYERS, SERUM-ALBUMIN ADSORPTION}, isbn = {0920-5063}, url = {://000224674600005}, author = {Janzen, J. and Le, Y. and Kizhakkedathu, J. N. and Brooks, D. E.} } @inbook {649, title = {Exact evaluation of collision integrals for the nonlinear Boltzmann equation}, booktitle = {Rarefied Gas Dynamics}, series = {Aip Conference Proceedings}, volume = {663}, year = {2003}, note = {ISI Document Delivery No.: BW84RTimes Cited: 0Cited Reference Count: 16Proceedings Paper23rd International Symposium on Rarefied Gas DynamicsJUL 20-25, 2002WHISTLER, CANADAUSAF, Univ SO Calif, Amer Inst Aeronaut \& Astronaut2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA}, pages = {35-42}, publisher = {Amer Inst Physics}, organization = {Amer Inst Physics}, address = {Melville}, abstract = {In this work, we evaluate analytically the collision integrals for the nonlinear isotropic Boltzmann equation for the hard spheres for several initial distribution functions. The initial distribution functions include combinations of Maxwellians with different temperatures and delta-functions. We do not find any preferential scattering into the high energy tail in the case when the initial distribution function is a sum of two Maxwellians with different temperatures. Our results may be used to devise a new method for the numerical integration of the nonlinear Boltzmann equation which avoids an approximate numerical evaluation of the collision integrals.}, keywords = {HOT OXYGEN, MODEL}, isbn = {0094-243X0-7354-0124-1}, url = {://000183372100005}, author = {Kabin, K. and Shizgal, B. D.}, editor = {Ketsdever, A. D. and Muntz, E. P.} } @article {643, title = {From the first to the second domain of gelsolin: a common path on the surface of actin?}, journal = {Febs Letters}, volume = {552}, number = {2-3}, year = {2003}, note = {ISI Document Delivery No.: 726DKTimes Cited: 22Cited Reference Count: 29}, month = {Sep}, pages = {86-90}, type = {Article}, abstract = {We present the 2.6. resolution crystal structure of a complex formed between G-actin and gelsolin fragment Met25-GIn160 (G1+). The structure differs from those of other gelsolin domain 1 (G1) complexes in that an additional six amino acid residues from the crucial linker region into gelsolin domain 2 (G2) are visible and are attached securely to the surface of actin. The linker segment extends away from G1 up the face of actin in a direction that infers G2 will bind along the same long-pitch helical strand as the actin bound to G1. This is consistent with a mechanism whereby G2 attaches gelsolin to the side of a filament and then directs G1 toward a position where it would disrupt actin-actin contacts. Alignment of the sequence of the structurally important residues within the G1-G2 linker with those of WH2 (WASp homology domain 2) domain protein family members (e.g. WASp (Wiscott-Aldridge syndrome protein) and thymosin beta4) suggests that the opposing activities of filament assembly and disassembly may exploit a common patch on the surface of actin. (C) 2003 Published by Elsevier B.V. on behalf of the Federation of European Biochemical Societies.}, keywords = {actin, BINDING, calcium, COMPLEX, crystal structure, DIFFRACTION DATA, F-ACTIN, FILAMENT, gelsolin, IDENTIFICATION, MODEL, MOTILITY, NUCLEATION, WH2 domain}, isbn = {0014-5793}, url = {://000185583000003}, author = {Irobi, E. and Burtnick, L. D. and Urosev, D. and Narayan, K. and Robinson, R. C.} } @article {341, title = {Accurately describing weak analyte-additive interactions by capillary electrophoresis}, journal = {Electrophoresis}, volume = {23}, number = {6}, year = {2002}, note = {ISI Document Delivery No.: 536KNTimes Cited: 12Cited Reference Count: 33}, month = {Mar}, pages = {880-888}, type = {Article}, abstract = {When modeling analyte-additive interactions in capillary electrophoresis (CE), it is necessary to correct for all changes in the apparent electrophoretic mobility of an analyte that are not due to specific binding. Current models based on dynamic complexation have corrected for bulk viscosity changes in the background electrolyte (BGE) when additives are used, while assuming negligible changes in the dielectric constant and other physicochemical properties of the solution. In this report, a study of weak interactions between deoxyribonucleotides and hydroxypropyl-beta-cyclodextrin (HP-beta-CD) revealed significant nonideality in binding isotherms. Changes in the dielectric properties of the solution due to the addition of high concentrations of HP-beta-CD to the BGE was observed to alter the electrophoretic mobility of analytes. A relative dielectric correction factor was required to normalize analyte mobilities to a reference state of zero additive concentration. The use of both a relative dielectric factor and a viscosity correction factor was found to increase the accuracy of the model, reflected by a higher degree of correlation between predicted and measured analyte mobilities. This type of correction is particularly relevant when studying weak analyte binding interactions or when using high concentrations of additive in the BGE. This work is vital for accurate determination of weak binding constants and mobility values, as well as providing a deeper understanding of the fundamental parameters influencing a separation in CE.}, keywords = {analyte-additive interactions, BETA-CYCLODEXTRIN, binding isotherms, capillary electrophoresis, CHIRAL SEPARATION, cyclodextrin, deoxyribonucleotides, DYNAMIC COMPLEXATION, ELECTROKINETIC CHROMATOGRAPHY, ELECTROPHORESIS, ENANTIOMERS, MIGRATION BEHAVIOR, MODEL, OPTIMIZATION, QUANTITATIVE DESCRIPTION, viscosity-dielectric corrections factors, weak, ZONE}, isbn = {0173-0835}, url = {://000174699400008}, author = {Britz-McKibbin, P. and Chen, D. D. Y.} } @article {531, title = {Numerical study of a direct current plasma sheath based on kinetic theory}, journal = {Physics of Plasmas}, volume = {9}, number = {2}, year = {2002}, note = {ISI Document Delivery No.: 514CHTimes Cited: 8Cited Reference Count: 43}, month = {Feb}, pages = {691-700}, type = {Article}, abstract = {A fully kinetic theory model was developed to study plasma properties of the sheath of a direct current glow discharge. This model includes a direct numerical solution of the Boltzmann equations for electron and ion distribution functions with a self-consistent electric field obtained from the Poisson equation. The calculated profiles of density, drift velocity, temperature, and electric potential were used to show the structure of the plasma sheath. The results of the direct numerical solution were compared with a particle-in-cell Monte Carlo simulation. It was also demonstrated that for a small Debye length to the ion mean-free path ratio, results obtained using the continuum sheath model, which includes two parameters, can be matched to the kinetic theory simulations. (C) 2002 American Institute of Physics.}, keywords = {BOHM CRITERION, CATHODE FALL, COLLISIONAL, ELECTRON MOTION, HELIUM, IONS, MODEL, MONTE-CARLO SIMULATION, RF GLOW-DISCHARGES, SHEATH, TRANSITION}, isbn = {1070-664X}, url = {://000173418700039}, author = {Vasenkov, A. V. and Shizgal, B. D.} } @article {446, title = {Orientational ordering and disordering of a simple dipolar fluid under shear flow}, journal = {Journal of Chemical Physics}, volume = {117}, number = {19}, year = {2002}, note = {ISI Document Delivery No.: 609YVTimes Cited: 4Cited Reference Count: 68}, month = {Nov}, pages = {9016-9027}, type = {Article}, abstract = {Nonequilibrium molecular dynamics simulations are performed for a simple dipolar fluid under planar Couette flow. Under this shear flow, the fluid{\textquoteright}s spatial structure becomes distorted, and the pair distribution function is anisotropic. At low shear rates, the dipoles respond to this distortion by orientationally ordering along an axis where the fluid structure is most compressed, giving a shear-induced ferroelectric fluid state. At high shear rates above a critical value, the orientational order decreases. We argue that this disordering can be attributed to the onset of large fluctuations in the director{\textquoteright}s orientation about the compression axis at the critical shear rate. We also observe the director can "hop" between "up" and "down" directions along the compression axis. These hops are fast and infrequent events. (C) 2002 American Institute of Physics.}, keywords = {BOUNDARY-CONDITIONS, COMPUTER-SIMULATION, DENSITY-FUNCTIONAL THEORY, HARD-SPHERES, LIQUID-CRYSTAL, LIVING POLYMERS, MODEL, NONEQUILIBRIUM-MOLECULAR-DYNAMICS, PHASE-SEPARATION, POLAR CLUSTERS, SELF-DIFFUSION}, isbn = {0021-9606}, url = {://000178934700045}, author = {McWhirter, J. L. and Patey, G. N.} } @article {530, title = {Self-consistent kinetic theory of a plasma sheath}, journal = {Physical Review E}, volume = {65}, number = {4}, year = {2002}, note = {ISI Document Delivery No.: 544FBTimes Cited: 8Cited Reference Count: 35Part 2B}, month = {Apr}, pages = {9}, type = {Article}, abstract = {A fully kinetic theory model of the sheath of a dc glow discharge is presented. This model includes a direct numerical solution of Boltzmann equations for the spatial and velocity dependence of the electron and Ar+ distribution functions with a self-consistent electric field calculated from the Poisson equation. The solution is obtained using a collocation method that employs Legendre quadrature points for both angular and spatial variables, and nonclassical speed quadrature points for velocity. The results of the steady state direct numerical solution are compared with a particle-in-cell Monte Carlo simulation. As anticipated, it is found that the space- and energy-dependent ion distribution function varies strongly with a decrease in the ratio of the Debye length to the ion mean free path.}, keywords = {COEFFICIENTS, COLLISIONLESS PLASMA, IONS, MODEL, MONTE-CARLO SIMULATION, MOTION, NEUTRALS, PRESHEATH, TRANSITION}, isbn = {1063-651X}, url = {://000175146600014}, author = {Vasenkov, A. V. and Shizgal, B. D.} } @article {469, title = {Theoretical Auger electron and X-ray emission spectra of CO and H2O by density functional theory calculations}, journal = {Chemical Physics Letters}, volume = {352}, number = {5-6}, year = {2002}, note = {ISI Document Delivery No.: 521CHTimes Cited: 3Cited Reference Count: 33}, month = {Feb}, pages = {511-520}, type = {Article}, abstract = {We propose a new method for analysis of X-ray emission and Auger electron spectra (XES and AES) of molecules involving the valence spectra using density functional theory (DFT) calculations. To obtain the more accurate transition energies and the relative intensities, we use the total-energy difference procedure (DeltaE-KS) for all transition energies, and transform the coefficients in the LCGTO-MO scheme in the DFT to those for the linear combination of the LCGTO-AO scheme. The method is applied to the analysis of valence spectra, XES and AES for CO and H2O molecules. The simulated spectra are in a good agreement with the experimental results. (C) 20021 Published by Elsevier Science B.V.}, keywords = {ACCURATE, APPROXIMATION, BINDING-ENERGIES, MODEL, PHOTOELECTRON-SPECTRA, POLYMERS}, isbn = {0009-2614}, url = {://000173820900032}, author = {Otsuka, T. and Chong, D. P. and Maki, J. and Kawabe, H. and Endo, K.} } @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} } @article {5175, title = {The disintegration of a molecule: The role of gelsolin in FAF, familial amyloidosis (Finnish type)}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {98}, number = {5}, year = {2001}, note = {ISI Document Delivery No.: 407EHTimes Cited: 8Cited Reference Count: 13}, month = {Feb}, pages = {2117-2118}, type = {Editorial Material}, keywords = {actin filament, MECHANISM, MODEL, PROTEIN}, isbn = {0027-8424}, url = {://000167258900003}, author = {Robinson, R. C. and Choe, S. Y. and Burtnick, L. D.} } @inbook {5198, title = {Hot oxygen in the exosphere of Venus}, booktitle = {Rarefied Gas Dynamics}, series = {Aip Conference Proceedings}, volume = {585}, year = {2001}, note = {ISI Document Delivery No.: BT38RTimes Cited: 1Cited Reference Count: 35Proceedings Paper22nd International Symposium on Rarefied Gas DynamicsJUL 09-14, 2000SYDNEY, AUSTRALIASandia Natl Labs, AFOSR/AOARD, ONR IFO Asia, Far E, DLR, USA Res Off, GAB Consulting Pty Ltd, Telstra2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA}, pages = {119-126}, publisher = {Amer Inst Physics}, organization = {Amer Inst Physics}, address = {Melville}, abstract = {It has now been firmly established from both theoretical calculations and observations, that the exospheres of the terrestrial planets have extended coronas of translational energetic oxygen atoms. The current model generally accepted as the source of these hot atoms is the dissociative recombination of OZ, that is, O-2(+) + e(-) {\textendash}> O* + O* where the product O* atoms are translationally energetic. The determination of the extent of this population of superthermal atoms is an important endeavor. The present paper considers a simple model based on the Boltzmann equation for the energy and altitude dependence of the oxygen atom distribution function. The density and temperature distributions are determined with this distribution.}, keywords = {ESCAPE, FRACTIONATION, GEOCORONA, HYDROGEN, KINETICS, MARS, MODEL, NITROGEN-ATOMS, O(P-3) ATOMS, UPPER-ATMOSPHERE}, isbn = {0094-243X0-7354-0025-3}, url = {://000172834300017}, author = {Shizgal, B. D.}, editor = {Bartel, T. J. and Gallis, M. A.} } @article {5213, title = {Nonhydrodynamic aspects of electron transport near a boundary: The Milne problem}, journal = {Physical Review E}, volume = {63}, number = {1}, year = {2001}, note = {ISI Document Delivery No.: 392HFTimes Cited: 2Cited Reference Count: 40Part 2}, month = {Jan}, pages = {11}, type = {Article}, abstract = {The nonhydrodynamic behavior of electrons near a boundary is studied with the Milne problem of transport theory. A system of electrons dilutely dispersed in a hear bath of atomic moderators is considered in the positive one-dimensional spatial half-space with an absorbing boundary at the origin which mimics an electrode. A flux of electrons is assumed to originate at an infinite distance Rom the boundary. The Fokker-Planck equation for the electron distribution function in space and velocity is considered. The density and temperature profiles are determined, and the departure from hydrodynamic behavior near the boundary is studied. Argon and helium are chosen as the moderators, and results with different cross sections are obtained. The Fokker-Planck equation is solved with an expansion in Legendre and Speed polynomials, and compared wherever possible with results obtained with a Monte Carlo simulation. The behavior near the boundary is shown to be strongly influenced by the Ramsauer-Townsend minimum in the electron-Ar momentum transfer cross section.}, keywords = {ARGON PLASMA, DEPENDENCE, equation, MODEL, MONTE-CARLO, RAREFIED-GAS FLOWS}, isbn = {1063-651X}, url = {://000166405100057}, author = {Vasenkov, A. V. and Shizgal, B. D.} } @article {4843, title = {Chirally modified zeolites as reaction media: Photochemistry of an achiral tropolone ether}, journal = {Organic Letters}, volume = {2}, number = {2}, year = {2000}, note = {ISI Document Delivery No.: 278ZETimes Cited: 49Cited Reference Count: 26}, month = {Jan}, pages = {119-121}, type = {Article}, abstract = {[GRAPHICS] Zeolites modified with chiral inductors serve as media for performing chiral induction during photochemical reactions of organic molecules. The photochemical behavior of achiral tropolone ethyl phenyl ether illustrates this unique feature of a zeolite.}, keywords = {AROMATICS, benzene, CATION-PI INTERACTIONS, CHEMISTRY, interactions, ION, MODEL, MOLECULE, STATE ORGANIC-PHOTOCHEMISTRY, WATER}, isbn = {1523-7060}, url = {://000085018200006}, author = {Joy, A. and Scheffer, J. R. and Ramamurthy, V.} } @article {4951, title = {First observation of a residual inter-cationic correlation in the {\textquoteright}super{\textquoteright}-ionic conductor, Ag9GaSe6: Ag-109-Ag-107 double-resonance NMR study of ion dynamics}, journal = {Solid State Ionics}, volume = {132}, number = {1-2}, year = {2000}, note = {ISI Document Delivery No.: 347GATimes Cited: 4Cited Reference Count: 37}, month = {Jul}, pages = {87-92}, type = {Article}, abstract = {A double-resonance nuclear magnetic resonance, NMR, signal between the very mobile nuclei of a superionic conductor has been detected for the first time in a silver conductor. The heteronuclear double-resonance signal between mobile nuclei should not be observed in the fast motion limit if the inter-cationic interactions are completely removed. However, a Ag-109-Ag-107 double-resonance signal has in fact been observed in a superionic conductor of 0.1-1 S m(-1), namely Ag9GaSe6. This implies that the cationic motion is correlated in this solid electrolyte and some residual interactions, perhaps including chemical bonds among very mobile cations, may remain even in the fast motion limit. (C) 2000 Elsevier Science B.V. All rights reserved.}, keywords = {DIFFUSION, double resonance NMR, ECHO DOUBLE-RESONANCE, GLASSES, ion dynamics, MODEL, SILVER IONS, silver superionic conductor}, isbn = {0167-2738}, url = {://000088918700008}, author = {Tansho, M. and Fyfe, C. A. and Grondey, H. and Markus, T. and Wada, H.} } @article {4840, title = {The influence of chiral auxiliaries is enhanced within zeolites}, journal = {Tetrahedron Letters}, volume = {41}, number = {43}, year = {2000}, note = {ISI Document Delivery No.: 368NKTimes Cited: 18Cited Reference Count: 20}, month = {Oct}, pages = {8231-8235}, type = {Article}, abstract = {Zeolites significantly enhance the influence of chiral auxiliaries during photochemical reactions. The generality of this phenomenon has been tested with three independent examples. Chiral auxiliaries that lead to 1:1 mixtures of diastereomers in solution give products in up to 80\% diastereomeric excess in the presence of faujasite type zeolites. (C) 2000 Elsevier Science Ltd. All rights reserved.}, keywords = {ASYMMETRIC PHOTOCHEMICAL-REACTIONS, ESTERS, INDUCTION, MODEL, SOLID-STATE}, isbn = {0040-4039}, url = {://000090123600010}, author = {Jayaraman, S. and Uppili, S. and Natarajan, A. and Joy, A. and Chong, K. C. W. and Netherton, M. R. and Zenova, A. and Scheffer, J. R. and Ramamurthy, V.} } @article {4742, title = {Size exclusion chromatography does not require pores}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {97}, number = {13}, year = {2000}, note = {ISI Document Delivery No.: 327UHTimes Cited: 16Cited Reference Count: 24}, month = {Jun}, pages = {7064-7067}, type = {Article}, abstract = {Separation of macromolecules on the basis of their molecular weight by size exclusion chromatography has long been considered to be caused by the geometry-dependent partition of macromolecules between a continuous phase and the porous interior of a gel or cross-linked bead. The volume of a pore accessible to a solute is limited by its relative dimensions, so larger molecules will have access to a smaller volume and will remain in a bead for a shorter time than smaller solutes. Our recent alternate picture proposes that the partition coefficient can be calculated from a thermodynamic model for the free energy of mixing of the solute with the gel phase. Size-dependent exclusion caused by the unfavorable entropy of mixing associated with the partition is predicted; the magnitude of the effect is modified by enthalpic: interactions between the solute and the gel phase. This concept is extended here to describe the partition of macromolecules into a layer of terminally attached polymer chains grafted onto a solid bead. Both simple mean field and self-consistent field theory calculations predict size-dependent entropic exclusion, Experimental results obtained with neutral polymer chains grafted onto solid polystyrene latex beads confirm the predictions.}, keywords = {CHAINS, MODEL}, isbn = {0027-8424}, url = {://000087811600027}, author = {Brooks, D. E. and Haynes, C. A. and Hritcu, D. and Steels, B. M. and Muller, W.} } @article {4947, title = {Theoretical valence photoelectron and UV-visible absorption spectra of four stable conductive molecules obtained by MO calculations}, journal = {Bulletin of the Chemical Society of Japan}, volume = {73}, number = {1}, year = {2000}, note = {ISI Document Delivery No.: 284WKTimes Cited: 4Cited Reference Count: 31}, month = {Jan}, pages = {43-51}, type = {Article}, abstract = {Theoretical valence photoelectron and UV-visible absorption spectra of four stable conductive molecules (N, N{\textquoteright}-diphenyl-1,4-phenylenediamine (DPPD), p-quaterphenyl (PQP), 2, 3, 7, 8, 12, 13, 17, 18-octaethyl-21H, 23H-porphyrin (OEP), and 29H, 31H-phthalocyanine (PC)) have been obtained by semiempirical HAM/3 and ZINDO MO calculations, respectively. The Al K alpha photoelectron spectra were simulated using Gaussian lineshape functions of an approximate linewidth 0.10 E-k (E-k = E-k{\textquoteright} - WD), where E-k{\textquoteright} is the vertical ionization potential (VIP) of each MO and WD is a shift to account for sample work function and other energy effects, as stated in previous studies. The theoretical valence spectra of the four conductive compounds are in good accordance with the observed ones. The theoretical UV-visible absorption curves of DPPD, PQP, OEP, and PC were obtained after AM1 calculations with COSMO option to reflect solvent effects. The absorption curves as simulated with Gaussian lineshape functions of a constant linewidth of 0.003 eV. Correspond well to the observed spectra. For PC, the simulated spectrum which consists of 0.5 inner protonation (IP) and 0.5 outer protonation (OP) types for PC-ring shows much better agreement with the experimental spectrum in H2SO4 than the spectrum of either TP or OP type alone.}, keywords = {HAM-3, MODEL, OLIGOMERS, PHTHALOCYANINES, POLYMERS, STATES, XPS}, isbn = {0009-2673}, url = {://000085355700005}, author = {Takaoka, K. and Maeda, S. and Miura, H. and Otsuka, T. and Endo, K. and Chong, D. P.} } @article {4666, title = {An analysis of O-H interaction potentials, O-H and O-D collision cross sections, and vibrational states}, journal = {Planetary and Space Science}, volume = {47}, number = {1-2}, year = {1999}, note = {ISI Document Delivery No.: 179JTTimes Cited: 3Cited Reference Count: 29}, month = {Jan-Feb}, pages = {163-174}, type = {Article}, abstract = {A detailed comparison of recently published OH, X(2)Pi, (2)Sigma(-), (4)Pi and (4)Sigma(-) potentials is carried out. These potential functions are important in the accurate determination of O-H and O-D collision cross sections. The isotope effect in the O-H and O-D cross sections plays an important role in the enhanced nonthermal escape of H and D from Mars and Venus. The quantum mechanical elastic scattering cross sections for O-H and O-D collisions are determined with a set of potentials which are constructed with a new interpolation of the short range tabulated potentials and the long range asymptotic behaviour. The important role of the asymptotic radial variation of the potential functions in the determination of the elastic cross sections is studied in detail with a semiclassical analysis, and a comparison is made with previous calculations. The vibrational energies for several different X(2)Pi bound potential functions for OH are also calculated and compared with published results. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.}, keywords = {DISCRETIZATION METHOD QDM, ENERGY, HYDROGEN, MODEL, MOLECULE, OXYGEN, VENUS}, isbn = {0032-0633}, url = {://000079324100017}, author = {Shizgal, B. D.} } @article {4661, title = {Cationic iron(III) complex with a hexadentate N-2,N {\textquoteright}(2),O-2-aminopyridylphenolate ligand}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {77}, number = {12}, year = {1999}, note = {ISI Document Delivery No.: 262KYTimes Cited: 14Cited Reference Count: 34}, month = {Dec}, pages = {2033-2038}, type = {Article}, abstract = {{Iron(III) complexation with potentially hexadentate H(2)bbpen (N,N{\textquoteright}-bis(2-hydroxybenzyl)-N,N{\textquoteright}-bis(2-methylpyridyl)ethylenediamine) was studied. The resulting monocationic complex, [Fe(bbpen)](+) as its NO3- and PF6- salts, was characterized by infrared spectroscopy, mass spectrometry, elemental analyses, cyclic voltammetry, and X-ray crystallographic analysis. Crystals of [Fe(bbpen)]NO3. CH3OH are monoclinic, space group P2(1)/c}, keywords = {ANALOGS, BINDING-SITE, CATIONIC, CRYSTAL-STRUCTURE, gallium, hexadentate, indium, iron( III), LACTOFERRIN, MODEL, OXO, phenolate, PROTEINS, pyridyl}, isbn = {0008-4042}, url = {://000084067500004}, author = {Setyawati, I. A. and Rettig, S. J. and Orvig, Chris} } @article {4554, title = {Computational prediction of the enantioselectivity of a solid-state photoreaction}, journal = {Organic Letters}, volume = {1}, number = {8}, year = {1999}, note = {ISI Document Delivery No.: 281QKTimes Cited: 8Cited Reference Count: 26}, month = {Oct}, pages = {1279-1281}, type = {Article}, abstract = {[GRAPHICS] To better understand the forces controlling chemical reactions in crystals, the absolute asymmetric photorearrangement of 4-m-chlorobenzyloxy-2-pyridone leading to the corresponding enantiomerically enriched (78\% ee) beta-lactam was modeled computationally using a flexible minilattice consisting of a central reactant and 20 nearest and 72 next-nearest neighbors. The computational results predicted a preference for formation of the (R,R)-enantiomer, and this was verified experimentally by absolute configuration correlation studies.}, keywords = {ABSOLUTE ASYMMETRIC-SYNTHESIS, CRYSTAL LATTICES, FORCE-FIELD, MEDIA, MODEL, MOLECULAR MECHANICS, NUCLEIC-ACIDS, PHOTOCHEMISTRY, PROTEINS}, isbn = {1523-7060}, url = {://000085172100037}, author = {Garcia-Garibay, M. A. and Houk, K. N. and Keating, A. E. and Cheer, C. J. and Leibovitch, M. and Scheffer, J. R. and Wu, L. C.} } @article {4417, title = {A semiclassical approach to intense-field above-threshold dissociation in the long wavelength limit. II. Conservation principles and coherence in surface hopping}, journal = {Journal of Chemical Physics}, volume = {109}, number = {14}, year = {1998}, note = {ISI Document Delivery No.: 125BETimes Cited: 28Cited Reference Count: 24}, month = {Oct}, pages = {5747-5760}, type = {Article}, abstract = {This paper is a companion to our recently published semiclassical formalism for treating time-dependent Hamiltonians [J. Chem. Phys, 105, 4094 (1996)], which was applied to study the dissociation of diatomic ions in intense laser fields. Here two fundamental issues concerning this formalism are discussed in depth: conservation principles and coherence. For time-dependent Hamiltonians, the conservation principle to apply during a trajectory hop depends upon the physical origin of the electronic transition, with total energy conservation and nuclear momentum conservation representing the two limiting cases. It is shown that a]applying an inappropriate scheme leads to unphysical features in the kinetic energy of the dissociation products. A method is introduced that smoothly bridges the two limiting cases and applies the physically justified conservation scheme at all times. It is also shown that the semiclassical formalism can predict erroneous results if the electronic amplitudes for well-separated hops are added coherently. This is a fundamental problem with the formalism which leads to unphysical results if left unattended. Alternative schemes are introduced for dealing with this problem and their accuracies are assessed. Generalization of the well-known Landau-Zener formula to the time-dependent Hamiltonian case is derived, which allows one to significantly decrease the computational overhead involved with the numerical implementation of the semiclassical method. Finally, we show that in strong-field molecular dissociation a trajectory can {\textquoteright}{\textquoteright}surf" a moving avoided crossing. In this case the hopping probability is a sensitive function of the interference between two closely spaced avoided crossing regions. (C) 1998 American Institute of Physics.}, keywords = {COULOMB EXPLOSION, DIATOMIC-MOLECULES, ENHANCED, H-2(+), IONIZATION, LASER FIELDS, MODEL, MOLECULAR-DYNAMICS, PHOTODISSOCIATION, QUANTUM DECOHERENCE, TRANSITIONS}, isbn = {0021-9606}, url = {://000076216900008}, author = {Thachuk, M. and Ivanov, M. Y. and Wardlaw, D. M.} } @article {4415, title = {Theoretical valence XPS and UV-visible absorption spectra of four leucodyes using MO calculations}, journal = {Bulletin of the Chemical Society of Japan}, volume = {71}, number = {4}, year = {1998}, note = {ISI Document Delivery No.: ZP865Times Cited: 8Cited Reference Count: 26}, month = {Apr}, pages = {807-816}, type = {Article}, abstract = {Semiempirical HAM/3 MO program was used to obtain the theoretical valence X-ray photoelectron spectra (XPS) of the two leuco dyes (2{\textquoteright}-anilino-6{\textquoteright}-diethylamino-3{\textquoteright}-methylspiro[isobenzofuran-1(3H),9{\textquoteright}-[9H] xanthene]-3-one (DEAMAF) and 3,3-bis(4-dimethylaminophenyl)-6-dimethylamino-1(3H)-isobenzofuranone (CVL)) and UV-visible adsorption spectra of the four leuco dyes (DEAMAF, CVL, 2{\textquoteright}-chloro-6{\textquoteright}-diethylamino-3{\textquoteright}-methylspiro[isobenzofuran-1 (3H),9{\textquoteright}-[9H]xanthene]3-one (DEAMCF), and 3{\textquoteright},6{\textquoteright}-bis(diethylamino)-spiro [isobenzofuran-1 (3H),9{\textquoteright}-[9H]]xanthene]-3-one (Rhodamine B base). The calculated Al K alpha photoelectron spectra were obtained using Gaussian lineshape functions of an approximate linewidth 0.10E(k) (E-k = E{\textquoteright}(k) -WD), where E{\textquoteright}(k) is the vertical ionization potential (VIP) of each MO and WD is a shift to account for sample work function, polarization energy and other energy effects. On the other hand, the absorption curves were simulated with Gaussian lineshape functions of a constant linewidth of 0.02 eV. The theoretical valence energy levels corresponded well to the spectra of two leuco dyes observed 0-40 eV, while the simulated adsorption spectra were shifted for a good fit with the experimental solution spectra in the range of 250-700 nm.}, keywords = {HAM-3, MODEL, POLYMERS, RAY PHOTOELECTRON-SPECTRA}, isbn = {0009-2673}, url = {://000073796400006}, author = {Takaoka, K. and Maeda, S. and Miura, H. and Endo, K. and Chong, D. P.} } @article {3887, title = {Liquid crystal phases of dipolar discotic particles}, journal = {Physical Review E}, volume = {55}, number = {1}, year = {1997}, note = {ISI Document Delivery No.: WD545Times Cited: 15Cited Reference Count: 21Part A}, month = {Jan}, pages = {447-454}, type = {Article}, abstract = {Fluids of dipolar oblate ellipsoids of revolution are investigated in detail employing molecular dynamics simulations. For aspect ratios (height-to-breadth) between similar to 1.2 and similar to 3, it is shown that these systems may form two liquid crystal phases. These are a ferroelectric phase which is stable at higher temperatures and an antiferroelectric columnar phase which is stable at lower temperatures. A partial phase diagram is given and the important structural features of these phases are determined and discussed.}, keywords = {COMPUTER-SIMULATION, ELLIPSOIDS, MODEL, MOLECULES, MONTE-CARLO SIMULATIONS, NEMATIC PHASE, orientational order, SPHERES, SYSTEMS}, isbn = {1063-651X}, url = {://A1997WD54500056}, author = {Ayton, G. and Wei, D. Q. and Patey, G. N.} } @article {3911, title = {Prediction of the migration behavior of analytes in capillary electrophoresis based on three fundamental parameters}, journal = {Journal of Chromatography A}, volume = {781}, number = {1-2}, year = {1997}, note = {ISI Document Delivery No.: YC198Times Cited: 11Cited Reference Count: 309th International Symposium on High Performance Capillary Electrophoresis and Related Microscale TechniquesJAN 26-30, 1997ORLANDO, FL}, month = {Sep}, pages = {23-34}, type = {Proceedings Paper}, abstract = {The prediction of analyte migration behavior in capillary electrophoresis (CE) is essential for rapid method development. The dynamic complexation model, based on 1:1 interactions, was used to accurately predict the apparent electrophoretic mobilities and the migration times of a group of deoxyribonucleotides (dNPs) at various concentrations of beta-cyclodextrin (beta-CD). The electrophoretic mobility of the analyte, the electrophoretic mobility of the analyte-additive complex and the equilibrium constant are the three fundamental parameters required to determine the mobility of an analyte. The apparent migration time of the analyte can be predicted once the electroosmotic mobility and relative viscosity of the solution are known. Optimum separation conditions can be determined based on these parameters. Excellent agreement between observed analyte migration behavior and predicted values was demonstrated, with relative errors being often less than 1\%. The theory was tested repeatedly under various conditions in order to assess its predictive capabilities and limitations. Analysis by molecular modelling, in conjunction with calculated electrophoretic parameters and equilibrium constants, provided deeper insight into the probable mechanisms of the separation process at the molecular level. (C) 1997 Elsevier Science B.V.}, keywords = {AFFINITY, BETA-CYCLODEXTRIN, BINDING, CHIRAL SEPARATION, CONSTANTS, deoxyribonucleotides, ELECTROKINETIC CHROMATOGRAPHY, ENANTIOMERS, migration behaviour, migration time prediction, MODEL, OPTIMIZATION, SELECTORS, TIOCONAZOLE}, isbn = {0021-9673}, url = {://A1997YC19800005}, author = {BritzMcKibbin, P. and Chen, D. D. Y.} } @article {3697, title = {Density functional computations for inner-shell excitation spectroscopy}, journal = {Chemical Physics Letters}, volume = {262}, number = {6}, year = {1996}, note = {ISI Document Delivery No.: VV284Times Cited: 28Cited Reference Count: 29}, month = {Nov}, pages = {729-732}, type = {Article}, abstract = {The 1s {\textendash}> pi* inner-shell excitation spectra of seven molecules have been studied using density functional theory along with the unrestricted generalized transition state (uGTS) approach. The exchange-correlation potential is based on a combined functional of Becke{\textquoteright}s exchange (B88) and Perdew{\textquoteright}s correlation (P86). A scaling procedure based on Clementi and Raimondi{\textquoteright}s rules for atomic screening is applied to the cc-pVTZ basis set of atoms where a partial core-hole is created in the uGTS calculations. The average absolute deviation between our predicted 1s {\textendash}> pi* excitation energies and experimental values is only 0.16 eV. Singlet-tripler splittings of C 1s {\textendash}> pi* transitions of CO, C2H2, C2H4, and C6H6 also agree with experimental observations. The average absolute deviation of our predicted core-electron binding energies and term values is 0.23 and 0.29 eV, respectively.}, keywords = {APPROXIMATION, ATOMS, CORE, ELECTRON BINDING-ENERGIES, GAS, MODEL, MOLECULES, SPECTRA, VALENCE-SHELL}, isbn = {0009-2614}, url = {://A1996VV28400009}, author = {Hu, C. H. and Chong, D. P.} } @article {3722, title = {Partial molar fluctuations in aqueous 2-butoxyethanol}, journal = {Bulletin of the Chemical Society of Japan}, volume = {69}, number = {6}, year = {1996}, note = {ISI Document Delivery No.: UY635Times Cited: 25Cited Reference Count: 13}, month = {Jun}, pages = {1505-1508}, type = {Article}, abstract = {The normalized fluctuations were reformulated in a unified manner, keeping the number of molecules in each coarse grain fixed. The normalized fluctuations were evaluated for aqueous 2-butoxyethanol using the existing data of chi(T), C-p, alpha(p), and V-m. The partial molar fluctuations of 2-butoxyethanol were then calculated. These quantities added some more evidences to the mixing schemes in aqueous 2-butoxyethanol conjectured earlier in this laboratory.}, keywords = {MODEL, SYSTEMS, VOLUMES, WATER-RICH REGION}, isbn = {0009-2673}, url = {://A1996UY63500005}, author = {Koga,Yoshikata and Westh, P.} } @article {3287, title = {Iron porphyrin catalyzed oxidation of lignin model compounds: Oxidation of phenylpropane and phenylpropene model compounds}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {73}, number = {12}, year = {1995}, note = {ISI Document Delivery No.: TV232Times Cited: 4Cited Reference Count: 41}, month = {Dec}, pages = {2153-2157}, type = {Article}, abstract = {The oxidation of 1-(4-ethoxy-3-methoxyphenyl)propane (2) and 1-(4-ethoxy-3-methoxyphenyl)propene (3) by meso-tetra(2,6-dichloro-3-sulphonatophe)porphyrin iron chloride (TDCSPPFeCl, 1) and tert-butylhydroperoxide (t-BuOOH) are discussed. In addition to a C-alpha-hydroxylation product, demethoxylation and direct aromatic ring cleavage products were found in the oxidation of 2. When 3 was oxidized by 1 and t-BuOOH in aqueous acetonitrile, an acetonitrile-incorporated product was found. A mechanism for the oxidation of 3 is proposed.}, keywords = {AROMATIC RING CLEAVAGE, BASIDIOMYCETE PHANEROCHAETE-CHRYSOSPORIUM, C BOND-CLEAVAGE, CHARACTERIZATION, DEGRADATION, DEGRADING ENZYME, DIARYLPROPANE, HEME-ENZYME, iron porphyrin, LIGNIN, ligninase, MODEL, OXYGENASE, POTASSIUM MONOPERSULFATE, SPECTRAL, VERATRYL ALCOHOL, WHITE ROT BASIDIOMYCETE}, isbn = {0008-4042}, url = {://A1995TV23200008}, author = {Cui, F. and Dolphin, D.} } @article {3119, title = {PORPHYRIN CHEMISTRY PERTAINING TO THE DESIGN OF ANTICANCER DRUGS .1. THE SYNTHESIS OF PORPHYRINS CONTAINING MESO-PYRIDYL AND MESO-SUBSTITUTED PHENYL FUNCTIONAL-GROUPS}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {72}, number = {9}, year = {1994}, note = {ISI Document Delivery No.: PJ994Times Cited: 37Cited Reference Count: 46}, month = {Sep}, pages = {1894-1909}, type = {Article}, abstract = {Condensation of pyrrole with a benzaldehyde and 4-pyridinecarboxaldehyde mixture yields the six possible meso-substituted phenyl or pyridyl porphyrins. Nitration of four of these has yielded 13 other porphyrins containing one to four 4-nitrophenyl moieties, and SnCl2 reduction of eight of these nitrophenylporphyrins gives the corresponding 4-aminophenyl(phenyl)- or 4-aminophenyl(phenyl)(4-pyridyl)porphyrins. Twelve of the porphyrins are new, but all 27 are fully characterized by H-1 NMR; resonances for every proton within each of the phenyl, pyridyl, and pyrrole rings are assigned. Trends in UV-VIS data are discussed, while IR and mass spectral data are noted for selected porphyrins.}, keywords = {METALLOPORPHYRINS, MODEL, NUCLEAR MAGNETIC-RESONANCE, OXYGEN, TETRAARYLPORPHYRINS, TUMORS}, isbn = {0008-4042}, url = {://A1994PJ99400002}, author = {Meng, G. Z. G. and James, Brian R. and Skov, K. A.} } @article {2846, title = {EXCESS PARTIAL MOLAR VOLUMES OF (XCH3(CH2)3O(CH2)2OH+(1-X)H2O) IN THE WATER-RICH REGION}, journal = {Journal of Chemical Thermodynamics}, volume = {25}, number = {1}, year = {1993}, note = {ISI Document Delivery No.: KH149Times Cited: 30Cited Reference Count: 14}, month = {Jan}, pages = {51-56}, type = {Article}, keywords = {2-BUTOXYETHANOL, 25-DEGREES-C, MIXTURES, MODEL}, isbn = {0021-9614}, url = {://A1993KH14900006}, author = {Koga,Yoshikata and Kristiansen, J. and Hvidt, A.} } @article {7285, title = {TRANSITION OF MIXING SCHEME IN THE WATER-RICH REGION OF AQUEOUS 2-BUTOXYETHANOL - PARTIAL MOLAR VOLUMES AND THEIR DERIVATIVES}, journal = {Journal of Physical Chemistry}, volume = {96}, number = {25}, year = {1992}, note = {ISI Document Delivery No.: KC007Times Cited: 30Cited Reference Count: 12}, month = {Dec}, pages = {10466-10468}, type = {Article}, abstract = {The mixing scheme boundary proposed in paper 1 (J. Phys. Chem. 1990, 94, 3879) was extended to high temperatures. Using the data of the excess partial molar volumes in aqueous solutions of 2-butoxyethanol (BE), V(m)E(i) (i = BE or H2O), reported in paper 2 (J. Chem. Thermodyn., in press), the composition derivatives of V(m)E(BE), (partial derivative V(m)(BE)/partial derivative n(BE))n(W), were calculated. n(BE) and n(W) are the amounts of BE and H2O in solution, respectively. It was found that these derivatives showed peak anomalies at the same loci of the mixing scheme boundary. In the water-rich region below the boundary, the behavior of the partial molar volumes and their derivatives was explained in a consistent manner as presented in previous papers (Can. J. Chem. 1989, 67, 67 1; J. Phys. Chem. 1990, 94, 3879; J. Phys. Chem. 1991, 95, 4119). We took into account three effects on V(m)E(BE): (1) the size difference between BE and W molecules; (2) the packing density of solvent H2O; (3) the progressive enhancement of the hydrogen-bond network of H2O as the concentration of BE increases.}, keywords = {25-DEGREES-C, MIXTURES, MODEL}, isbn = {0022-3654}, url = {://A1992KC00700064}, author = {Koga,Yoshikata} } @article {6959, title = {CONTINUUM ELECTROSTATIC INTERACTIONS BETWEEN PLANAR LATTICES OF DIPOLES AND THE POSSIBLE RELEVANCE TO THE HYDRATION FORCE}, journal = {Physical Review A}, volume = {43}, number = {6}, year = {1991}, note = {ISI Document Delivery No.: FD045Times Cited: 11Cited Reference Count: 37}, month = {Mar}, pages = {2953-2962}, type = {Article}, abstract = {The electrostatic interaction between two planar dipolar lattices in dielectric continua is investigated. If there are no dielectric images, the pressure is equally likely to be attractive or repulsive, depending upon the relative lateral displacement of the two lattices. In addition to perfect dipolar lattices, we consider the effects of real dipoles, of disorder, and of finite-sized domains. When the surfaces constitute the boundary between dielectric media, and when there are no correlations between the two surfaces, then there occurs a strong exponentially decaying repulsion due to the interaction between a lattice and its dielectric images. The relevance of this repulsion to the hydration force is discussed, and an experimental test that should discriminate between different theories for that force is proposed.}, keywords = {BILAYER SYSTEMS, DEPENDENCE, DOUBLE-LAYER, ELECTROLYTE-SOLUTIONS, MICA, MOBILE, MODEL, ORIENTABLE DIPOLES, polarization, SURFACES, WATER}, isbn = {1050-2947}, url = {://A1991FD04500037}, author = {Attard, P. and Patey, G. N.} } @article {6958, title = {INTERACTION FREE-ENERGY BETWEEN PLANAR WALLS IN DENSE FLUIDS - AN ORNSTEIN-ZERNIKE APPROACH WITH RESULTS FOR HARD-SPHERE, LENNARD-JONES, AND DIPOLAR SYSTEMS}, journal = {Physical Review A}, volume = {44}, number = {12}, year = {1991}, note = {ISI Document Delivery No.: GW604Times Cited: 63Cited Reference Count: 43}, month = {Dec}, pages = {8224-8234}, type = {Article}, abstract = {The interaction free energy per unit area between planar walls is given as a convolution of wall-solvent pair-correlation functions. This result, derived from the large radius limit of the macrosphere-solvent Ornstein-Zernike equations, and from the hypernetted-chain closure, provides a statistical-mechanical basis for the Derjaguin approximation, and is both generally applicable and computationally tractable. It is found that the interaction between hard walls in a hard-sphere fluid is oscillatory, and in good agreement with simulations. The van der Waals attraction emerges from asymptotic analyses of Lennard-Jones and dipolar fluids, and the full expression allows calculation of this quantity down to molecular separations. This is demonstrated by numerical results for dipolar fluids.}, keywords = {APPROXIMATION, ELECTRICAL DOUBLE-LAYERS, ELECTROLYTES, equation, HYPERNETTED-CHAIN, INHOMOGENEOUS FLUIDS, INVARIANT EXPANSION, MODEL, MONTE-CARLO, SURFACES}, isbn = {1050-2947}, url = {://A1991GW60400049}, author = {Attard, P. and Berard, D. R. and Ursenbach, C. P. and Patey, G. N.} }