Electrokinetic flow of an aqueous electrolyte in amorphous silica nanotubes.

We study the pressure-driven flow of aqueous NaCl in amorphous silica nanotubes using nonequilibrium molecular dynamics simulations featuring both polarizable and non-polarizable molecular models. Different pressures, electrolyte concentrations and pore sizes are examined. Our results indicate a flow that deviates considerably from the predictions of Poiseuille fluid mechanics.

The docking of chiral analytes on proline-based chiral stationary phases: A molecular dynamics study of selectivity.

Molecular dynamics simulations are employed to examine the selectivity of four proline-based chiral stationary phases in two solvent environments, a relatively apolar n-hexane/2-propanol solvent and a polar water/methanol solvent. The four chiral surfaces are based on a BOC-terminated diproline, a TMA-terminated diproline, a TMA-terminated triproline and a TMA-terminated hexaproline. This range of chiral selectors allows an analysis of the impact of oligomer length and terminal group on selectivity while the two solvent environments indicate the impact of solvent hydrogen bonding and polarity.

The photoexcitation of crystalline ice and amorphous solid water: A molecular dynamics study of outcomes at 11 K and 125 K.

Photoexcitation of crystalline ice Ih and amorphous solid water at 7-9 eV is examined using molecular dynamics simulations and a fully flexible water model. The probabilities of photofragment desorption, trapping, and recombination are examined for crystalline ice at 11 K and at 125 K and for amorphous solid water at 11 K. For 11 K crystalline ice, a fully rigid water model is also employed for comparison.

Algorithms for GPU-based molecular dynamics simulations of complex fluids: Applications to water, mixtures, and liquid crystals.

A custom code for molecular dynamics simulations has been designed to run on CUDA-enabled NVIDIA graphics processing units (GPUs). The double-precision code simulates multicomponent fluids, with intramolecular and intermolecular forces, coarse-grained and atomistic models, holonomic constraints, Nosé-Hoover thermostats, and the generation of distribution functions. Algorithms to compute Lennard-Jones and Gay-Berne interactions, and the electrostatic force using Ewald summations, are discussed.

Poly-proline-based chiral stationary phases: a molecular dynamics study of triproline, tetraproline, pentaproline and hexaproline interfaces.

Poly-proline chains and derivatives have been recently examined as the basis for new chiral stationary phases in high performance liquid chromatography. The selectivity of poly-proline has been measured for peptides with up to ten proline units. In this article, we employ molecular dynamics simulations to examine the interfacial structure and solvation of surface-bound poly-proline chiral selectors.

Molecular dynamics simulations to examine structure, energetics, and evaporation/condensation dynamics in small charged clusters of water or methanol containing a single monatomic ion.

We study small clusters of water or methanol containing a single Ca(2+), Na(+), or Cl(-) ion with classical molecular dynamics simulations, using models that incorporate polarizability via the Drude oscillator framework. Evaporation and condensation of solvent from these clusters is examined in two systems, (1) for isolated clusters initially prepared at different temperatures and (2) those with a surrounding inert (Ar) gas of varying temperature. We examine these clusters over a range of sizes, from almost bare ions up to 40 solvent molecules.

On simulations of complex interfaces: molecular dynamics simulations of stationary phases.

Methodological considerations for molecular dynamics simulations of complex interfaces are presented in this article. A slab geometry is examined in the context of stationary phases where selectivity occurs predominantly in pores within silica beads. Specifically, we examine the Whelk-O1 interface with n-hexane/2-propanol, the TMA-(Pro)(2)-N(CH(3))-tether interface with n-hexane/2-propanol, and the C(18)H(37)Si interface with water/methanol.

Low serum creatinine levels as risk factor of diabetes mellitus: prediabetes considerations.

Objective: It has been reported that low serum creatinine level is a risk factor of diabetes. We hypothesize that should this be true, serum creatinine levels would be lower and more prevalent in prediabetes than in normal individuals.

Materials And Methods: 1017 glucose tolerance tests performed at South West Pathology Service of the New South Wales Health, Australia, in 2008 were sorted into normal (control), prediabetes and diabetes based on decisive interpretation.

How are completely desolvated ions produced in electrospray ionization: insights from molecular dynamics simulations.

We apply molecular dynamics (MD) simulations to study the final phase of electrospray ionization (ESI), where an ion loses all of its associated solvent molecules. By applying an electric field to a cluster of H(2)O molecules solvating an ion and including a surrounding gas of varying pressure, we demonstrate that collisions with the gas play a major role in removing this final layer of solvent. We make quantitative predictions of the critical velocity required for the cluster to start losing molecules via collisions with gas and propose that this should be important in real ESI experiments.

Proline-based chiral stationary phases: a molecular dynamics study of the interfacial structure.

Proline chains have generated considerable interest as a possible basis for new selectors in chiral chromatography. In this article, we employ molecular dynamics simulations to examine the interfacial structure of two diproline chiral selectors, one with a terminal trimethylacetyl group and one with a terminal t-butyl carbamate group. The solvents consist of a relatively apolar n-hexane/2-propanol and a polar water/methanol mixture.

Position paper for health authorities: archived clinical pathology data-treasure to revalue and appropriate.

Archived clinical pathology data (ACPD) is recognized as useful for research. Given our privileged de-identified ACPD from South West Pathology Service (SWPS), attempt is made to estimate what it would cost any researcher without such privilege to generate the same data. The Ethics Committee of the Area Health Service approved a request for Dr.

Whole blood viscosity issues VI: Association with blood salicylate level and gastrointestinal bleeding.

Background: This series on whole blood viscosity issues has been trying to elucidate the sensitivity, specificity and usefulness of the laboratory parameter in clinical practice. The postulation has been that since antiplatelet is used in the management of stasis, of which blood viscosity is an index, the latter would be useful laboratory indication and/or contraindication.

Aim: The aim of this study was to observe whether blood level of acetylsalicylic acid differs with the level of whole blood viscosity.

Whole blood viscosity assessment issues III: Association with international normalized ratio and thrombocytopenia.

Background: Anticoagulant and antiplatelet therapies are being used interchangeably or in combination. While international normalized ratio is assessed to determine anticoagulant's contraindication/need, whole blood viscosity is not assessed to determine the need for antiplatelet.

Aims: The objective of this study is to investigate whether whole blood viscosity value is associated with levels of international normalized ratio and platelet count.

Molecular dynamics simulations of the liquid-crystal phases of 2-(4-butyloxyphenyl)-5-octyloxypyrimidine and 5-(4-butyloxyphenyl)-2-octyloxypyrimidine.

In this paper, molecular dynamics simulations are employed to study the liquid-crystal phases of 2-(4-butyloxyphenyl)-5-octyloxypyrimidine and 5-(4-butyloxyphenyl)-2-octyloxypyrimidine. Both mesogens consist of aromatic phenyl-pyrimidine cores in between two identical alkoxy tails, but they differ in the preferred core conformation. The ab initio-based derivation of suitable molecular models is discussed in detail, with particular emphasis on capturing proper ring-ring interactions.

Whole blood viscosity determination in diabetes management: perspective in practice.

Background: Antiplatelet and antioxidant nutritional therapies (ANT) are commonly used in diabetes management. Guidelines recommend identifying deficiencies of antioxidant vitamins and condition of no contraindication for nutritional and antiplatelet respectively.

Aim: To determine whether the guidelines recommendations for diabetes patients to be assessed for (1) antioxidant vitamins' deficiencies and/or (2) whole blood viscosity (WBV) as indication of no antiplatelet contraindication.

Rational optimization of the Whelk-O1 chiral stationary phase using molecular dynamics simulations.

Rational in silico optimization of the Whelk-O1 chiral stationary phase (CSP) has been carried out based on the chiral recognition mechanism extracted from previous molecular dynamics simulations [C.F. Zhao, N.

A molecular dynamics study of chirality transfer from chiral surfaces to nearby solvent.

The presence of a chiral surface can alter the characteristics of nearby solvent molecules such that, on average, these molecules become chiral. The extent of this induced chirality and its dependence on the surface and solvent characteristics are explored in this article. Three surfaces employed in chiral chromatography are examined: The Whelk-O1 interface, a phenylglycine-derived chiral stationary phase (CSP), and a leucine-derived CSP.

Cardiovascular risk assessment in prediabetes: A hypothesis.

There are screening programs for future risk of cardiovascular disease (CVD) complications in diabetes, but not in subclinical diabetes. There is little or no risk and no differences between genders when a man or woman at age below 50 years presents blood pressure below 140/90 mmHg and total cholesterol/HDL less down 7.0.

Solvation of phenylglycine- and leucine-derived chiral stationary phases: molecular dynamics simulation study.

A theoretical study of the solvation of ( R)- N-(3,5-dinitrobenzoyl)phenylglycine- and ( R)- N-(3,5-dinitrobenzoyl)leucine-derived chiral stationary phases (CSPs) is presented. Semiflexible models of the chiral selectors are prepared from B3LYP/6-311G** calculations, and these are used in the molecular dynamics simulations of the corresponding interface. The chiral interface is examined for four solvents: 100% hexane, 90:10 hexane:2-propanol, 80:20 hexane:2-propanol, and 100% 2-propanol.

A molecular dynamics study of chirality transfer: The impact of a chiral solute on an achiral solvent.

A solvation shell may adapt to the presence of a chiral solute by becoming chiral. The extent of this chirality transfer and its dependence on the solute and solvent characteristics are explored in this article. Molecular dynamics simulations of solvated chiral analytes form the basis of the analysis.

Molecular dynamics study of chiral recognition for the whelk-O1 chiral stationary phase.

In this article, we examine the docking of 10 analytes on the Whelk-O1 stationary phase. A proper representation of analyte flexibility is essential in the docking analysis, and analyte force fields have been developed from a series of B3LYP calculations. Molecular dynamics simulations of a representative Whelk-O1 interface, in the presence of racemic analyte and solvent, form the basis of the analysis of chiral selectivity.

Polarizable and flexible model for ethanol.

A polarizable, flexible model for ethanol is obtained based on an extensive series of B3LYP/6-311++G(d,p) calculations and molecular dynamics simulations. The ethanol model includes electric-field dependence in both the atomic charges and the intramolecular degrees of freedom. Field-dependent intramolecular potentials have been attempted only once previously, for OH and HH stretches in water [P.

The docking of chiral epoxides on the Whelk-O1 stationary phase: a molecular dynamics study.

The docking of analytes on the Whelk-O1 chiral stationary phase is explored for two chiral epoxides in a hexane solvent. Density functional theory calculations are employed to develop flexible models for R/S-styrene oxide (phenyl oxirane) and (R,R/S,S)-stilbene oxide (2,3-diphenyl oxirane). Molecular dynamics simulations of the racemates in the presence of the Whelk-O1 chiral stationary phase reveal the distribution of the enantiomers at the interface.