The rate of oxygen utilization by the electron transport system at low oxygen concentrations has been difficult to explain mechanistically (l-3). As in most enzymatic reactions the rate of oxygen utiliiation is independent of oxygen concentration when the oxygen concentration is high, but becomes dependent upon the oxygen concentration at some critical value of the oxygen tension. Chance (4) ha...

A Bodipy-based energy transfer cassette with a singlet oxygen reactive linker between the donor and acceptor modules has an interesting emergent property, if the acceptor module is also a photosensitizer. Singlet oxygen produced by the photosensitizer reacts rapidly with the molecule itself to liberate the energy donor, resulting in an enhanced fluorescence emission. The result is a self-report...

The purpose of this work is to compare gas movement through potato tuber tissue with the respiratory rate of such tissue and to assess possible oxygen deficiency as a factor in the limitation of respiration within the tissue. Argon 37 was used as a substitute for oxygen in most of the gas transfer experiments because it is easier to measure, its solubilities and diffusion coefficients are very ...

This study demonstrates the applicability of pressurized stirred tank bioreactors for oxygen transfer enhancement in aerobic cultivation processes. The specific power input and the reactor pressure was employed as process variable. As model organism Escherichia coli, Arxula adeninivorans, Saccharomyces cerevisiae and Corynebacterium glutamicum were cultivated to high cell densities. By applying...

Rate constants for recombination and hole transfer during oxygen evolution at illuminated α-Fe(2)O(3) electrodes were measured by intensity-modulated photocurrent spectroscopy and found to be remarkably low. Treatment of the electrode with a Co(II) solution suppressed surface recombination but did not catalyse hole transfer. Intermediates in the reaction were detected spectroscopically.

Bioartificial liver support provides a bridge to transplantation which is at present the only proven specific treatment for acute liver failure. In this paper, a novel multi-coaxial hollow fiber bioreactor so-called "Fibre-in-Fibre FIF Bioartificial liver device" with three compartments is experimentally and mathematically studied. The mathematical model in this paper is an extension of Krogh c...

a classical theory is developed which calculates the momentum transfer rate constant between an ion and a non-polar molecule. the model takes into consideration the effect of diffraction outside the capture limit on the rate constants. the theory is used to calculate momentum transfer rate constant for cl- with trans-dichloroethylene and para-difluorobenzene. theoretical results are compared to...

The present study reports the effects of aeration and agitation on growth and production of the cyclosporin A (CyA) in batch fermentor cultures of Tolypocladium inflatum MTCC 557. Dissolved oxygen concentration, pH, dry cell wt, CyA titer and sugar utilization were continuously measured and determined. In the first step, the effect of agitation was evaluated by changing the agitation speed in t...

In this study, hydrodynamics and physiology of microorganisms were investigated in a new type membrane bioreactor, MHCR, which is a membrane coupled HCR (High performance Compact Reactor) having very high COD removal efficiency. The degree of interference caused by inserting a submerged membrane was evaluated quantitatively by measuring the air suction rate and overall oxygen transfer coefficie...