[Composite biodegradable materials based on polyhydroxyalkanoate].

Conditions for the processing and mixing of biodegradable polymers at temperatures less than their thermal destruction (130-150 degrees C) using standard equipment have been identified. The structure of the polyhydroxybutyrate/valerate (PHB/V) copolymer has been revealed and peculiarities of the crystal phase formation at different monomer ratios have been investigated. It was shown that pure PHB with molecular mass 180-270 kDa has elastic module approximately 1.2 GPa, strength approximately 25 MPa, and elongation at break approximately 10%. The most active biodestructors of PHB, PHB/V, and their composites have been selected (Aspergillus caespitosus), and the ability of basidiomycete Panus tigrinus to biodegrade polyalkanoates was demonstrated for the first time. It was shown that A. caespitosus degraded PHB/V and Biopol films along with the PHB with the destruction rate depending on the technology of the film production, on the molecular mass, and on the extend of the polymer crystallinity.

[Use of LKhM-80 chromatograph in the analysis of urinary steroids]. / Primenenie khromatografa LKhM-80 dlia analiza steroidov mochi.

The paper describes a simple way of updating a Russian production-type LKaM-80 chromatograph in order to make a gas chromatographic analysis of urinary steroids for separation by using high performance capillary columns. To connect capillary columns, the units consisting of a gas heaving T-joint, a stream separating chamber, and a releasing restrictor were applied. To achieve satisfactory results, it is necessary to place a column through the tube connecting the union for attachment of the column and the flame-ionization detector so that the end of a capillary should be located at the detector as soon as closer. The updated chromatograph has been successfully used to obtain urinary steroidal profiles which are essential for the differential diagnosis of causes of hyperandrogyny in females, including pregnants.