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H J Purz

Publications and source records attributed to H J Purz.

5 recordsLinked to original sources
PubMed1986

Fast cryofixation technique for X-ray microanalysis.

The proposed cryofixation technique uses a tubule-shaped needle chilled in liquid propane for simultaneous excision and freezing of a tissue specimen. Due to this simultaneity, ionic shifts created by traumatic influences are avoided even in the outermost cells of the specimen. Moreover, it is shown here that stopping the blood flow for more than about 10 s results in notable ionic shifts between cells and extracellular space in rat heart and liver. Such preparative ischaemic injury is minimized by the Fast Cryofixation Technique because it can be easily performed on organs within the circulatory system, whilst the heart of the animal is still beating. Intracellular concentrations of the monovalent ions in rat heart and liver, obtained by this method, tally well with recent results from different independent techniques reported in the literature. As demonstrated by cross-sectioning and freeze-fracturing, the structural preservation of the freezing technique is sufficient for X-ray microanalytical work.

Animals↗
PubMed1981

Some methodical aspects and applications of freeze-etching in polymer research.

The freeze-etching method is used for investigating the morphology of aqueous polymer systems, e.g. network-like segregation structures of cryofixed polymer solutions and real network structures in polymer gels. The cooling rate, which is decisive for cryofixation of specimens, is measured by a thermocouple and a pyroelectric element in different coolants. The effect of the cooling rate on the freeze-etching structure of polymer solutions, polymer gels and a 10% aqueous glycerol solution as a model substance is determined and compared. The increase of the cooling rate in polymer gels results in maintaining the original network structure, in smaller segregation compartments in polymer solutions and in smaller crystallites in the cryofixed ice matrix.

Crystallization↗
PubMed1976

[Rheology and spinning of alkaline solutions of sunflower seed globulin and casein].

The specific demand of sodium hydroxide is determined for the dissolution of sunflower seed globulin, casein and a mixture of them to equal parts. In low protein-containing solutions it depends for sunflower seed globulin very much on the sodium chloride concentration. From sunflower seed globulin, casein and a mixture of them to equal parts are prepared with sodium hydroxide high protein-containing alkaline solutions. Sunflower seed globulin forms temporally a gel phase. After this phase the solution of sunflower seed globulin shows like casein and a mixture of sunflower seed globulin/casein (I:I) pseudoplastic flow. The flow curves of the pseudoplastic solutions are described mathematically with the OSWALDian power statement. By alkaline solutions of casein and sunflower seed globulin/casein (I:I) the flow exponent n is distributed statistically about 0.9, by solutions of sunflower seed globulin a distribution exists about the mean values n = 0.85 and n = 0.50. lg k depends in all protein solutions on the concentration of protein, sodium chloride, sodium hydroxide and on the temperature and time. For all protein solutions exists a linear relation between the logarithm of viscosity and the reciprocal temperature for lg k and I/T, which is derived normally for NEWTONian flow behaviour. In a suitable scope of spinning for all protein solutions are carried out complete factorial experiment, which guide to regression equations of lg k; in the case of sunflower seed globulin are calculated also a regression equation of the flow exponent n. Going out from the parameters of the spinning process the properties of the spun sunflower seed globulin/casein (I:I) fibers are described.

Caseins↗