This paper deals with the facilitated diffusion of oxygen in systems containing proteins, such as ferrohemoglobin, that combine reversibly with oxygen. The phenomenon is treated in terms of translational diffusion of free and bound oxygen molecules, and of the reaction rate of the oxygen molecules with the oxygen-binding protein. These considerations lead to a differential equation (see Equatio...

The mechanism of melibiose symport by the melibiose permease of Escherichia coli was investigated by further analyzing the Na+ (H+ or Li+)-coupled facilitated diffusion reactions catalyzed by the carrier in de-energized membrane vesicles, with particular emphasis on the reaction of sugar exchange at equilibrium. It is first shown that melibiose exchange at equilibrium proceeds without concomita...

Nuclear pore complexes provide the sole gateway for the exchange of material between nucleus and cytoplasm of interphase eukaryotic cells. They support two modes of transport: passive diffusion of ions, metabolites, and intermediate-sized macromolecules and facilitated, receptor-mediated translocation of proteins, RNA, and ribonucleoprotein complexes. It is generally assumed that both modes of ...

BACKGROUND The early steps of human immunodeficiency virus 1 (HIV-1) replication involve reverse transcription of the viral RNA and integration of the resulting cDNA into a host chromosome. The DNA integration step requires the integration machinery ('preintegration complex') to bind to the host DNA before connecting the viral and host DNAs. Here, we present experiments that distinguish among t...

In cross-country skiing races, the difference between fastest and second time can be minuscule. As in all endurance sports, requires use of energy to overcome resistive forces, this case primarily aerodynamic drag friction skis snow. Even a slight reduction either these determine outcome race. The geometry ski exerts profound influence on result flexible modern skis, camber profile gliding prop...

traditional systems for olefin/paraffin separation, like low-temperature distillation, are expensive and very energy consuming, and therefore, alternative separation methods are desired. facilitated transport membranes are new tools for this separation to be substituted in large scale separation of olefin-paraffin mixtures. to design a membrane process for olefin-paraffin separation, equilibriu...

A self-induced, non-traumatic testicular torsion is a rare entity that to our knowledge has not been reported in the literature. We report the case of a 28-year-old male who caused a self-induced testicular torsion during acts associated with cross dressing. Differential diagnosis of the acute scrotum in an adult should always include testicular torsion, as outcomes in this population are worse...

Rapid manufacturing facilitated customization C. J. Tuck a , R. J. M. Hague a , M. Ruffo a , M. Ransley b & P. Adams b a Rapid Manufacturing Research Group , Wolfson School of Mechanical and Manufacturing Engineering, Loughborough University , Loughborough, Leicestershire, LE11 3TU, UK b Martin Baker Aircraft Company Limited, Higher Denham , Uxbridge, Middlesex, UB9 5AJ, UK Published online: 25...

An approximation technique is introduced that greatly facilitates the estimation of the Epidemic-Type Aftershock Sequence (ETAS) model introduced by Ogata (1988), which is widely used to describe earthquake catalogs. The proposed approximation greatly simplifies the integral term in the log-likelihood, the computation of which is by far the greatest hurdle in maximum likelihood estimation. The ...