A density functional theory for polymer fluids is derived. The form of the identical to a continuum self-consistent-field but we show that with correct ‘‘mean field,’’ exact. We apply fluid made up tangential hard spheres and borrow from successful simple obtain nonlocal expression this mean field. latter depends only upon monomer density. This approximation used treat problem mixture such polymers spheres, contained in slitlike pores. Comparison simulations theory, though structure,...

An electric double layer is studied by means of Monte Carlo simulations and mean-field theory. The counterions the uniformly charged surfaces are modeled as flexible polyelectrolytes. For this particular model system it turns out that traditional repulsion becomes attractive for a wide range systems. main reason attraction an entropically driven bridging mechanism, its magnitude significant compared to ordinary or van der Waals forces. polyelectrolyte Poisson–Boltzmann theory developed here...

A theory for nonuniform polymer melts is presented, which combines density functional with Monte Carlo methods. The treats the ideal gas exactly via a single chain simulation and uses weighted approximation excess free energy functional. bulk fluid properties required in are obtained from generalized Flory equation of state. predictions compared to simulations profiles semiflexible confined between flat plates. Good agreement found 3mers 20mers several densities molecular stiffnesses.

We develop and apply test particle methods to calculate chemical potentials in uniform non-uniform electrolytes using computer simulations. Our techniques are based on the well-known Widom method, but account for non-electroneutral fluctuations, implicitly suppressed a usual Canonical Ensemble Monte Carlo simulation. These fluctuations shown contribute greatly average single ionic species. compare our results with similar Grand simulations 1:1, 2:1 2:2 electrolytes, 1:1 at charged planar...

We investigate theoretical models of room temperature ionic liquids, and find that the experimentally observed camel-shape differential capacitance is strongly related to dispersion interactions in these systems. At low surface charge densities, loss vicinity electrodes generates depleted with a concomitant drop capacitance. This behavior not where have been removed.

In the Poisson–Boltzmann theory of macroion screening in electrolyte solutions chief simplifying assumption is neglect correlations within ionic atmosphere. Using a generalized van der Waals density functional analysis incorporating ion–ion correlation local approximation we obtain simple corrected theory. For point charges salt free case, this leads to asymptotic instability (a ‘‘structuring catastrophe’’) though correction well behaved low orders perturbation Results zeroth order and field...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTExistence of stable structural isomers ketene. A theoretical study the C2H2O potential energy surfaceWillem J. Bouma, Ross H. Nobes, Leo Radom, and Clifford WoodwardCite this: Org. Chem. 1982, 47, 10, 1869–1875Publication Date (Print):May 1, 1982Publication History Published online1 May 2002Published inissue 1 1982https://pubs.acs.org/doi/10.1021/jo00349a010https://doi.org/10.1021/jo00349a010research-articleACS PublicationsRequest reuse...

Large anions are attracted to hydrophobic surfaces while smaller, well solvated ions repelled. Using a combination of explicit solvent and continuum model simulations we show that this leads significant ion-specific protein-protein interactions due patches on the protein surfaces. In solutions NaI NaCl calculate potentials mean force find resulting second virial coefficients for lysozyme correspond with experiment. We argue ionic nonpolar surface groups may play an important role...

We present a simple, classical density functional approach to the study of simple models room temperature ionic liquids. Dispersion attractions as well ion correlation effects and excluded volume packing are taken into account. The oligomeric structure, common many liquid molecules, is handled by polymer treatment. theory evaluated comparisons with simulations, an emphasis on differential capacitance, experimentally measurable quantity significant practical interest.

Molecular simulations show that arginine-rich peptides can stabilize transient membrane pores induced by lipid flip-flop.

Wide-field fluorescence microscopy at high magnification was used to study the intracellular binding site of Rubb16 in Escherichia coli. Upon incubation E. coli cells minimum inhibitory concentration, localised ribosomes with no significant DNA observed. Furthermore, condensed when they existed as polysomes. It is postulated that condensation polysomes would halt protein production, and thereby inhibit bacterial growth. The results this indicate family inert dinuclear ruthenium complexes...

Confocal microscopy was used to study the intracellular localisation of a series inert polypyridylruthenium(II) complexes with three eukaryotic cells lines - baby hamster kidney (BHK), human embryonic (HEK-293) and liver carcinoma (Hep-G2). Co-staining experiments DNA-selective dye DAPI demonstrated that di-, tri- tetra-nuclear are linked by bis[4(4'-methyl-2,2'-bipyridyl)]-1,12-dodecane bridging ligand ("bb12") showed high degree selectivity for nucleus cells. Additional co-localisation...

The prototypical antimicrobial peptide, melittin, is well-known for its ability to induce pores in zwitterionic model lipid membranes. However, the mechanism by which melittin accomplishes this not fully understood. We have conducted all-atom and coarse-grained molecular dynamics simulations suggest that employs a highly cooperative induction of both small large membrane pores. process peptide induces appears be driven affinity defects via N-terminus region. In our simulations, defect was...

We explore the influence of ion pairing in room temperature ionic liquids confined by planar electrode surfaces. Using a coarse-grained model for aromatic liquid [C4MIM(+)][BF4 (-)], we account an component as equilibrium associating species within classical density functional theory. investigated resulting structure electrical double layer well ensuing surface forces and differential capacitance, function degree association. found that short-range adjacent to surfaces was remarkably...

The structure of polymer solutions confined between hard walls is investigated via density functional theory. A generalized Flory theory for mixtures incorporating an equation state dimers implemented in the without introducing any adjustable parameters. predicted by good agreement with computer simulations melts, lengths ranging from 3 mers to 20 and several volume fractions. Similarly found 8-mer/monomer mixtures.

Orientational correlation functions have been obtained from Monte Carlo simulations of long, freely jointed chains (1000 monomers and more) with screened Coulomb interactions truncated after a certain number bonds. This makes it possible to study chain-length dependence without "end effects" display excluded-volume effects. These form the basis for discussion conformational response electrostatic interactions. In particular, they are related concept persistence length illustrate differences...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA Monte Carlo simulation study of the interaction between charged colloids carrying adsorbed polyelectrolytesM. K. Granfeldt, Bo Joensson, and C. E. WoodwardCite this: J. Phys. Chem. 1991, 95, 12, 4819–4826Publication Date (Print):June 1, 1991Publication History Published online1 May 2002Published inissue 1 June 1991https://pubs.acs.org/doi/10.1021/j100165a042https://doi.org/10.1021/j100165a042research-articleACS PublicationsRequest reuse...

A simpler method for the purification of cucurbit[10]uril (Q[10]) from Q[10]·Q[5] inclusion complex is reported. 1,12-Diaminododecane was used to displace Q[5], as opposed synthetic melamine derivative currently used. The binding trans-[{PtCl(NH3)2}2(µ-NH2(CH2)8NH2)]2+ (CT008) and [{Ru(phen)2}2(µ-bb5)]4+ {phen = 1,10-phenanthroline; bb5 1,5-bis[4(4′-methyl-2,2′-bipyridyl)]pentane} (Rubb5) Q[10] studied by 1H NMR luminescence spectroscopy, cyclic voltammetry molecular modelling. resonances...

We present a dielectric continuum model that, at semiquantitative level, explains why ion pair formation in water is favored by like-sized ions over unlike-sized pairs. Using both classical and ab initio approaches, we show that the now well-established empirical rule, so-called "law of matching affinities", can be rationalized terms solvation. Namely, pairing differently sized weakened due to shadowing effect where larger shields smaller from solvent. It shown this law ceases valid for less...

Abundant peptides and proteins containing arginine (Arg) lysine (Lys) amino acids can apparently permeate cell membranes with ease. However, the mechanisms by which these succeed in traversing free energy barrier imposed remain largely unestablished. Precise thermodynamic studies (both theoretical experimental) on interactions of Arg Lys residues model lipid bilayers provide valuable clues to efficacy cationic proteins. We have carried out molecular dynamics simulations calculate ionized...

We have implemented a generic coarse-grained model for the aromatic ionic liquid [CnMIM+][Tf2N–]. Various lengths alkyl chain on cation define homologous series, whose electric properties are expected to vary in systematic way. Within framework of classical density functional theory, interfacial structures members this series compared over range surface charge densities, lengths, and geometries. The differential capacitance double layer, formed by liquids against charged electrode, is...

Arginine-rich cell penetrating peptides (ARCPPs) are known to quickly permeate membranes through a non-endocytotic pathway. Potential clinical applications of this facility have prompted enormous effort, both experimental and theoretical, better understand how ARCPPs manage overcome the prodigious thermodynamic cost lipid bilayer permeation by these highly charged peptides. In work we report results all-atom simulations, which suggest that kinetic (rather than thermodynamic) mechanism may...

Monte Carlo simulations of linear, weak polyacids and explicit simple ions have been performed in a spherical cell model to study the shift apparent dissociation constant. The are canonical ensemble with constant calculated procedure based on Widom's particle-insertion method. effects parameters discussed, for example, influence various distances closest approach, results compared experiments as well effective pair-potentials between monomers, both screened Coulomb potential an extended...

The weaker emission typically seen for iridium(III) cyclometalated complexes in aqueous medium can be reversed via encapsulation cucurbit[10]uril (Q[10]). Q[10] cavity is shown to effectively maximize quantum yields the complexes, compared any other medium. This may provide significant advantages a number of sensor applications. NMR studies show that are accommodated similarly within host molecule, even with cationic substituents attached ppy ligands, indicating hydrophobic effect dominant...

Membrane-active peptides (MAPs) are able to induce pores in cell membranes via molecular mechanisms, which still subject ongoing research. In this work, we present dynamics simulations that suggest a precursor membrane defect plays an important role the pore-inducing activity of prototypical antimicrobial peptide melittin. The reveal hydrophobic N-terminus melittin is recognize and insert into lipid bilayer leads cascading transfer adsorbed defect, leading aggregation pore. We show mechanism...