A computer modeling technique has been developed which allows for the prediction of chromatographic separation and stationary-phase selectivity. This technique enables development of application-specific gas chromatographic columns by allowing for the simultaneous optimization of physical dimensions, flow and temperature programs, and stationary-phase composition. Stationary-phase selectivity i...

We report a microfabricated gas chromatography (GC) column that uses a thin layer of high-quality singlewalled carbon nanotubes (SWNTs) as a stationary phase. This 1.0-m-long, 160-μm-wide, 250-μm-deep column has the highest separation efficiency reported to date for microfabricated columns having an SWNT stationary phase. Separation efficiency was evaluated with a Golay plot, in which the minim...

By analysing the growth kinetics of Dictyostelium discoideum amoebae in varying combinations of the components of the nutrient medium HL-5 (Cocucci & Sussman, 1970), we have demonstrated that Dictyostelium amoebae enter stationary phase when they deplete the medium of one or more nutrient components. However, if the medium of a stationary phase culture is supplemented with any of the initial co...

A novel Congo red (CR) derivatized silica stationary phase was prepared and packed into a fused silica capillary tube for nano-flow HPLC. A variety of analytes including poly-aromatic hydrocarbons, parabens, acids, sulfonamides, bases, and nucleosides were successfully separated using the CR. In comparison with commercial ODS columns, this new stationary phase has a different separation mechani...

kinetics of single cell protein production from natural gas by a microorganism (a methylomonas sp.) was studied experimentally and by modeling at equal amount of air and natural gas. kinetic models of monod, moser, teissier, aiba, andrews, and noack were used for illustrating cell growth. methane and oxygen were considered as limited substrates with concentration in the range 2-10 mg/lit. death...

A finite element simulation has been used in order to study the partition chromatography process of one species between an aqueous mobile phase and an organic stationary phase located at the bottom of a rectangular microchannel. The transient model incorporates convection--diffusion of the species in the water phase coupled to the diffusion in the stationary organic phase by the way of the part...

The effects of growth phase and carbon source on membrane-associated phosphatidylinositol kinase in cell extracts of Saccharomyces cerevisiae were examined. Phosphatidylinositol kinase activity increased 2- and 2.5-fold in glucose- and glycerol-grown cells, respectively, in the stationary phase as compared with the exponential phase of growth. The increase in phosphatidylinositol kinase activit...

The 16-kDa protein, an alpha-crystallin homologue, is one of the most abundant proteins in stationary-phase Mycobacterium tuberculosis. Here, transcription and translation of the hspX gene, which encodes the 16-kDa protein, have been investigated by Northern blotting analysis, primer extension, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis with a microaerophilic stationary-phase...

Endogenous and exogenous accumulation of nucleobases was observed when Escherichia coli entered the stationary phase. The onset of the stationary phase was accompanied by excretion of uracil and xanthine. Except for uracil and xanthine, other nucleobases (except for minor amounts of hypoxanthine), nucleosides, and nucleotides (except for cyclic AMP) were not detected in significant amounts in t...