We employ a multiscale approach to model the translocation of biopolymers through nanometer size pores. Our computational scheme combines microscopic Langevin molecular dynamics (MD) with a mesoscopic lattice Boltzmann (LB) method for the solvent dynamics, explicitly taking into account the interactions of the molecule with the surrounding fluid. Both dynamical and statistical aspects of the tr...

Reactive events in proteins may be strongly coupled to a few specific modes of protein motion or they may couple nonspecifically to the dense continuum of protein and solvent modes. We summarize the evidence that at least some biologically important reactions can be described in terms of a few specific modes, and we propose experiments to quantify the strength of coupling to the continuum. We a...

The use of dimethylsulfoxide as a solvent for synthetic purine and urea derivatives in the tobacco callus bioassay for cytokinin activity (10) has simplified the test procedure at two stages. First, the high solubility of these compounds in DMSO' has made it possible to test the less active materials, or those which are only slightly water-soluble, through a wide range of concentrations; second...

A simple and efficient homogenous liquid-liquid extraction method performed in a narrow tube combined with dispersive liquid-liquid microextraction method has been presented for the simultaneous determination of two antiepileptic drugs in urine followed by gas chromatography with flame ionization detection. In this method, a mixture of acetonitrile and urine sample (homogenous solution) is load...

A simple and efficient homogenous liquid-liquid extraction method performed in a narrow tube combined with dispersive liquid-liquid microextraction method has been presented for the simultaneous determination of two antiepileptic drugs in urine followed by gas chromatography with flame ionization detection. In this method, a mixture of acetonitrile and urine sample (homogenous solution) is load...

Chemical speciation of Pb(II), Cd(II), Hg(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes of L-glutamic acid was studied at 303 K in 0–60 vol. % 1,2-propanediol–water mixtures, whereby the ionic strength was maintained at 0.16 mol dm-3. The active forms of the ligand are  3 LH , LH2 and LH–. The predominant detected species were ML, ML2, MLH, ML2H and ML2H2. The trend of the variation in the ...

There are six tocol analogs present in palm oil, namely α-tocopherol (α-T), α-tocomonoenol (α-T₁), α-tocotrienol (α-T₃), γ-tocotrienol (γ-T₃), β-tocotrioenol (β-T₃) and δ-tocotrienol (δ-T₃). These analogs were difficult to separate chromatographically due to their similar structures, physical and chemical properties. This paper reports on the effect of pressure and injection solvent on the sepa...

Electrostatic interactions in proteins are potentially quite strong, but these interactions are mitigated by the screening effects of water, ions, and nearby protein atoms. The early work of Kirkwood and Westheimer on small organic molecules showed that the extent of the screening may depend on whether charged or dipolar groups are involved. The dielectric and ionic screening of the interaction...

We address the response of a random heteropolymer to preferential solvation of certain monomer types at the globule-solvent interface. For each set of monomers that can comprise the molecule's surface, we represent the ensemble of allowed configurations by a Gaussian distribution of energy levels, whose mean and variance depend on the set's composition. Within such a random energy model, mean s...

Real-world observable physical and chemical characteristics are increasingly being calculated from the 3D structures of biomolecules. Methods for calculating pKa values, binding constants of ligands, and changes in protein stability are readily available, but often the limiting step in computational biology is the conversion of PDB structures into formats ready for use with biomolecular simulat...