The extraction and transesterification of soil lipids into fatty acid methyl esters (FAMEs) is a useful technique for studying soil microbial communities. The objective of this study was to find the best solvent mixture to extract soil lipids with a pressurized solvent extractor system. Four solvent mixtures were selected for testing: chloroform:methanol:phosphate buffer (1:2:0.8, v/v/v), chlor...

We investigate the usefulness of a frozen-density embedding scheme within density-functional theory [J. Phys. Chem. 97, 8050 (1993)] for the calculation of solvatochromic shifts. The frozen-density calculations, particularly of excitation energies have two clear advantages over the standard supermolecule calculations: (i) calculations for much larger systems are feasible, since the time-consumi...

An asymmetric microgear will spontaneously and unidirectionally rotate if it is heated in a cool surrounding solvent. The resulting temperature gradient along the edges of the gear teeth translates in a directed thermophoretic force, which will exert a net torque on the gear. By means of computer simulations, the validity of this scenario is proved. The rotational direction and speed are depend...

The sedimentation of an initially inhomogeneous distribution of hard-sphere colloids confined in a slit is simulated using the multi-particle collision dynamics scheme which takes into account hydrodynamic interactions mediated by the solvent. This system is an example for soft matter driven out of equilibrium where various length and time scales are involved. The initial laterally homogeneous ...

The thermodynamics of polymeric networks subject to the action of a solvent is reviewed. Expressions for the osmotic compressibility and elastic moduli (bulk and shear) of the swollen network are derived in relation to the molecular characterjstiics of the system. The dependence of the osmotic compressibility on the equilibrium degree of swelling and the solvent quality is investigated. A stron...

A theoretical treatment of electron angular momentum relaxation in atoms induced by electric field fluctuations in a liquid solvent cage is presented. It is shown that in the case of weak interaction between solvent shell and a "target" atom the rate of transitions between the components of a Kramers doublet decreases sharply with the increase of adiabatic splitting between the terms of atomic ...

The effect of the addition of ethylene glycol (EG) on the interfacial adsorption and micellar properties of the alkylglucoside surfactant n-octyl-β-D-thioglucopyranoside (OTG) has been investigated. Critical micelle concentrations (cmc) upon EG addition were obtained by both surface tension measurements and the pyrene 1:3 ratio method. A systematic increase in the cmc induced by the presence of...

A molecular-dynamics simulation method has been applied to investigate the influence of the mobile-phase composition on the retention of solutes in HPLC. The distribution profiles of the distance between two atoms in ODS ligands were constructed to characterize the conformation of ODS ligand molecules. The distinct difference of ODS conformation is observed by comparing molecular models consist...

microspheres formulated from poly (d,l-lactic-co-glycolide) (plga), a biodegradable polymer, have been extensively evaluated as a drug delivery system. in this study, the preparation, characterization and drug release properties of the plga microspheres were evaluated. simvastatin (sim)-loaded plga microspheres were prepared by oil-in-water emulsion/solvent evaporation method. the microspheres ...