Conventional modeling of two-phase dilute suspensions is achieved with the Euler equations for the gas phase and gas dynamics pressureless equations for the dispersed phase, the two systems being coupled by various relaxation terms. The gas phase equations form a hyperbolic system but the particle phase corresponds to a hyperbolic degenerated one. Numerical difficulties are thus present when de...

A high-performance liquid chromatography (HPLC) method for the determination of azadirachtin (A and B) residues in bovine muscle has been developed. Azadirachtin is a neutral triterpene and chemotherapeutic agent effective in controlling some pest flies in horses, stables, horns and fruit. The actual HPLC method uses an isocratic elution and UV detection. Liquid-liquid extraction and solid-phas...

BACKGROUND RNA from sorted cell populations is crucial in many instances. We therefore compared four current protocols for RNA isolation, with regard to mRNA yield and purity. Moreover, we examined the effects on RNA recovery caused by different storage reagents. METHODS Small populations of K562 cells or PMBC were sorted into the lysing reagent and subjected to RNA extraction, employing eith...

We develop heterodyned dispersed vibrational echo spectroscopy (HDVE) and demonstrate the new capabilities in biophysical applications. HDVE is a robust ultrafast technique that provides a characterization of the real and imaginary components of third-order nonlinear signals with high sensitivity and single-laser-shot capability and can be used to extract dispersed pump-probe and dispersed vibr...

We report the application of the dispersive liquid-liquid microextraction coupled to hollow-fibre membrane-assisted liquid-phase microextraction and its application for extraction of atrazine and triclosan. Under optimum conditions, namely, 25 μL of a 1 : 4 chlorobenzene : ethyl acetate mixture dispersed in 1 mL of aqueous sample, 10% (m/v) NaCl, a magnetic stirrer speed at 600 rpm, and 10 minu...

A high-performance liquid chromatographic procedure with a postcolumn fluorescence derivatization is developed for the analysis of oleandrin in bovine blood. Oleandrin is separated by an octadecylsilane-bonded column with a mobile phase containing dehydroascorbic acid. The effluent of the column is mixed with concentrated hydrochloric acid and passed through poly(tetrafluoroethylene) tubing mai...

A procedure is described that uses high-pressure liquid chromatography for assay of gentamicin in serum. The technique involves extraction of gentamicin from serum by using a CM-Sephadex column and analysis by reverse-phase, ion-pair chromatography. Continuous-flow, post-column derivatization with o-phthaladehyde is used to form fluorescent products for detection. The possible scope of this met...

A polymeric microfluidic device for solid-phase extraction (SPE)-based isolation of nucleic acids is demonstrated. The plastic chip can function as a disposable sample preparation system for different biological and diagnostic applications. The chip was fabricated in a cyclic polyolefin by hot-embossing with a master mold. The solid phase consisted of a porous monolithic polymer column impregna...

A simple, specific and sensitive high-performance liquid chromatographic (HPLC) method was developed for the determination of rifampin in human plasma. Rifampin and sulindac (internal standard) are extracted from human plasma using a C2 Bond Elut extraction column. A 100-microliter volume of 0.1 M HCl is added to the plasma before extraction to increase the retention of the compounds on the ext...