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[Letter: Effect of a reversible increase in plasma membrane permeability of plant root cells during deplasmolysis].

The studied effect of a reversible increase of permeability of plasmic membranes of plant root cells does not depend on chemical nature of plasmolys-inducing agents. This effect is conditioned by the process of deplasmolysis itself. It is suggested that the process of reversible depolimerization of the protein component similar to F-action and located in the membrane polar regions.

Cell Membrane Permeability↗

Development and biopharmaceutical evaluation of osmotic pump tablets for controlled delivery of diclofenac sodium.

Based on the principles of an elementary osmotic pump (OP), OP tablets were designed and evaluated with the aim to deliver diclofenac sodium (DS) in a controlled manner. In vitro evaluation was done in various release media and kinetics was evaluated using the regression coefficient analysis. Effects of orifice size, coating membrane type, coating thickness, static and stirred conditions and pH variation were studied. In vivo evaluation was performed on six healthy human volunteers and various pharmacokinetic parameters (c(max), t(max), AUC(0-24), MRT) and relative bioavailability were calculated. The results were compared with the performance of two commercial tablets of DS. The drug release from OP tablets was dependent on the type and thickness of the coating membrane, but was independent of the orifice size and static and stirred conditions of the release medium. The OP tablets provided a prolonged and controlled DS release compared to commercial sustained-release and conventional tablets of DS.

Administration, Oral↗

Use of fouling resistant nanofiltration and reverse osmosis membranes for dyeing wastewater effluent treatment.

Dyeing wastewater was post-treated by using nanofiltration (NF) and reverse osmosis (RO) membranes. To reduce membrane fouling, poly (vinyl alcohol) (PVA) with a neutral charge was coated on NF and RO membranes. The effect of surface charge and surface roughness on membrane fouling was investigated. Dyeing wastewater was pre-treated by using coagulation, activated sludge process, and MF process to investigate the effect of the pre-treatment on the membrane fouling. It is demonstrated that the extent of fouling is significantly influenced by the surface roughness and the surface charge on the NF and RO membranes. A membrane with a smooth and neutral surface was fouled less. The pre-treatment was essential for avoiding NF and RO membranes fouling. The quality of the final permeate was acceptable for water reuse.

Bioreactors↗

Mathematical model equation of the volume flows through polymeric membrane of heterogeneous non-ionic solutions.

Formalism leading to more general form of the Kedem-Katchalsky equation describing osmotic membrane transport, considering local unhomogenity of solutions called concentration boundary layers and influence of gravitational factor on membrane transport kinetics was presented. In order to test this formalism, osmotic volume flux was calculated, on the basis of experimental membrane transport parameters and aqueous glucose solutions in isothermal conditions. Obtained calculation's results are conformable to adequate experimental results presented in previous paper for flat polymeric membrane used in medicine (Biophys. Chem. 1986, 24, 173).

Glucose↗