Epidemiological assessment of the system of indices characterizing the quality of vaccine preparations

The authors discuss the methodology and the method of formation of the medico-technical requirements to newly-elaborated or modified vaccine preparations. The following are considered among the principal parameters responsible for the formation of the quality of the vaccines: the prophylactic activity, the extent of the injurious effect, the technological and the exploitation properties. A close association of these parameters in the determination of the quality of the vaccine and the dependence of the efficacy of its use on the character of the epidemic situation was shown. A possibility of using the method of calculation of the efficacy of immunization for detection of the main (leading) parameters of the quality of the vaccine elaborated which should be used in composing the medico-technical requirements. It is emphasize that one of the principal directions of the investigations is the elaboration and the assessment of the correctness of the immunological and laboratory methods of standardization and control of the methods of objective measurement of the parameters forming the quality of the vaccine preparations.     

Free volume and the physico‐mechanical behaviour of polyurethane/polyacrylonitrile interpenetrating polymer networks: positron annihilation results

A series of semi‐interpenetrating polymer networks (SIPNs) of polyurethane (PU) and polyacrylonitrile (PAN) in the weight ratios 90/10, 70/30, 60/40 and 50/50 PU/PAN were prepared using polyethylene glycol, 4,4′‐diphenylmethane diisocyanate and acrylonitrile by sequential polymerization. Differential scanning calorimetry and scanning electron microscopy techniques were used to find the glass transition temperature and surface morphology of SIPNs. The tough and transparent SIPN films were characterized for physico‐mechanical properties such as density, surface hardness and tensile properties. Positron annihilation lifetime spectroscopy (PALS) was used to measure the free volume behaviour of the IPNs. The sorption behaviour of IPNs with benzene penetrant was also measured. An attempt was made to correlate the PALS results with the mechanical and sorption properties of the SIPNs. Copyright © 2005 Society of Chemical Industry