Cell growth and retamycin production in Streptomyces olindensis So20 were studied at different dissolved oxygen levels during fermentation. The profiles for cell growth and retamycin production in an experiment with dissolved oxygen control at 5% air saturation during production were similar to those in an experiment without dissolved oxygen control. However, despite slower cell growth, a twofo...

as surfactants enhance the membrane transport of organic compounds, it has to be assumed that they decisively influence the absorption of pollutants from house dust. sampling sites for the surfactant analysis include housing areas, each location of which has different surroundings such as rural, urban, construction, and industrial area. three stations had been selected for each housing area and...

in this study, doxycycline hyclate release behavior from in situ forming drug delivery systems investigated. these systems based on poly()lactide-co-glycolide)(50:50 dissolved in n-methyl-2-pyrrolidone that were evaluated in different concentrations. these systems are useful for local treatment of periodontal diseases. uv spectroscopy is used to determine drug concentration in release medium. a...

The different types of mineral industries wastes are characterized. Total tonnage in the world of finely ground wastes from i.a. flotation and leaching operations amounts to around 1 500 million tons per annum. The major environmental problems arise from slowly settling fine particles, dissolved metal ions and chemicals retained in the effluent. The paper discusses the toxic effects of dissolve...

-The impacts of dissolved oxygen (DO) on the sorption of natural and model humic substances by granular activated carbon (GAC) were investigated. Among five substances tested, the sotptions of only two, polymaleic acid (PMA) and peat humic acid, were affected by the presence of DO. The uptake of the target compound o-cresol on virgin GAC and on GAC preloaded with PMA under oxic and anoxic condi...

Pelagic ecosystems can become depleted of dissolved oxygen as a result of both natural processes and anthropogenic effects. As dissolved oxygen concentration decreases, energy shifts from macrofauna to microorganisms, which persist in these hypoxic zones. Oxygen-limited regions are rapidly expanding globally; however, patterns of microbial communities associated with dissolved oxygen gradients ...