Mechanical parameters of dispersed systems under cyclic deformation with various amplitudes

The mechanical behavior is reported for dispersed systems subject to cyclic deformation with or without steady-state flow. The mechanical characteristics are found to alter considerably.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 18, No. 6, pp. 987–993, June, 1970.     

Assessment of regional myocardial uptake and metabolism of omega-(p-123I-phenyl) pentadecanoic acid with serial single-photon emission tomography

The utility of myocardial imaging and assessment of regional myocardial metabolism of omega-(123I-paraphenyl-)pentadecanoic acid (I-PPA) by means of serial single-photon tomography is demonstrated in animal experiments. High quality cross sectional images of dog hearts with clear delineation of left ventricular walls are obtained. Myocardial infarcts are visualized as areas of deficient radioactivity uptake. I-PPA elimination from non-infarcted myocardial regions is significantly (p less than 0.001) prolonged when compared with unaffected controls. Hence, not only localized absence of uptake of free fatty acid by infarcted myocardium can be demonstrated with serial single-photon tomography but also general impairment of cardiac FFA-metabolism.     

Theory of filtration of non -newtonian liquids through porous media

The flow of abnormally viscous liquids through screens with pores of rectangular cross section is examined.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 20, No. 6, pp. 1115–1118, June, 1971.     

Stabilization and activation of {alpha}-chymotrypsin in water-organic solvent systems by complex formation with oligoamines

Formation of enzyme–oligoamine complexes was suggestedas an approach to obtain biocatalysts with enhanced resistancetowards inactivation in water–organic media. Complex formationresults in broadening (by 20–40% v/v ethanol) of the rangeof cosolvent concentrations where the enzyme retains its catalyticactivity (stabilization effect). At moderate cosolvent concentrations(20–40% v/v) complex formation activates the enzyme (by3–6 times). The magnitude of activation and stabilizationeffects increases with the number of possible electrostaticcontacts between the protein surface and the molecules of oligoamines(OA). Circular dichroism spectra in the far-UV region show thatcomplex formation stabilizes protein conformation and preventsaggregation in water–organic solvent mixtures. Two populationsof the complexes with different thermodynamic stabilities werefound in -chymotrypsin (CT)–OA systems depending on theCT/OA ratio. The average dissociation constants and stoichiometriesof both low- and high-affinity populations of the complexeswere estimated. It appears that it is the low-affinity siteson the CT surface that are responsible for the activation effect.     

Determination of the parameters of multilayer nanostructures using two-wave X-ray reflectometry

A method for determining the parameters of multilayer nanostructures by measuring the angular dependence of the X-ray reflectance at two wavelengths has been considered. A calculation scheme taking into account the specificity of the method was suggested, which allows operation with samples of any size and shape. The scheme was applied to C/Ni/C, Si_1?xGe_x, and Al_xGa_1?xAs multilayer structures. It was shown that two-wave reflectometry allows elimination of the influence of instrumental errors; hence, the thickness, density, and composition of both polycrystalline and monocrystalline nanostructure layers reliably determined.