I studied the effects of serum dilution and oxidation of albumin-bound bilirubin on the accuracy of results by the peroxidase method for assessing bilirubin-albumin binding. The apparent concentration of unbound bilirubin decreases with dilution of bilirubin-enriched serum or defatted-albumin solutions, the effect being more marked with serum. The decrease in apparent unbound bilirubin does not...

Sugar-cane stalks, 2.0 cm long, were used as a support for yeast immobilization envisaging ethanol production. The assays were conducted in 38.5 L fermenters containing a bed of stalks with 50% porosity. The operational stability of the immobilized yeast, the efficiency and stability of the process, as well as the best dilution rate were evaluated. Molasses from demerara sugar production was us...

BACKGROUND: Lovastatin is known to inhibit its own synthesis in the fungus Aspergillus terreus. Therefore, the use of a fermentation strategy that continuously removes some of the lovastatin produced from the bioreactor can enhance its productivity. This paper reports on the effects of dilution rate and the composition of the feed medium on lovastatin production by A. terreus. RESULTS: The feed...

Changes in dilution rate did not elicit large and systematic changes in cellular cyclic AMP levels in Escherichia coli grown in a chemostat under carbon or phosphate limitation. However, the technical difficulties of measuring low levels of cellular cyclic AMP in the presence of a large background of extracellular cyclic AMP precluded firm conclusions in this point. The net rate of cyclic AMP s...

Nonlinear control design techniques for a class of continuous biological processes with growth and production decoupling are investigated. We establish, under realistic assumptions on the kinetics, that though neither the inlet substrate concentration nor the dilution rate can achieve linearization of the global dynamics, we can maximize the dimension of the linear system obtained after feedbac...

The present work was aimed to design and develop self-nanoemulsifying drug delivery systems (SNEDDS) with the objective to overcome the problems associated with the delivery of talinolol, a hydrophobic and poorly bioavailable drugs having pH dependant solubility. The solubility of talinolol in various oils, surfactants, cosurfactants and aqueous phases were determined to identify and select the...

Phytoplankton growth and stoichiometry depend on the availability of multiple nutrients. We use a mathematical model of phytoplankton with flexible stoichiometry to explain patterns of phytoplankton composition in chemostat experiments and nutrient drawdown dynamics that are found in the field. Exponential growth and equilibrium represent two distinct phases, each amenable to mathematical analy...

Analysis of the Luedeking-Piret model during the oxidative respiration to respirofermentative transition in a consortium grown in a chemostat revealed a significant increase in a parameter (β) of the Luedeking-Piret model in butyrate production. These data implied the possibility of improved capacity for cellular metabolites production under some culture conditions. Additionally, the parameter ...

background and objective: lactic acid is widely used in the food, chemical and pharmaceutical industries. the major problems associated with lactic acid production are substrate and end-product inhibition, and by-product formation. membrane technology represents one of the most effective processes for lactic acid production. the aim of this work is to increase cell density and lactic acid produ...