Formulation of perspective hepatoprotector polymeric forms based on silybin and ursodeoxycholic acid

Russian Chemical Bulletin - Silybin (Slb) and ursodeoxycholic acid (UDCA) are hepatoprotectors used in the pathogenetic therapy of liver and biliary tract. However, low bioavailability of these...     

Reduction of amorphous Fe(III)-hydroxide by binary microbial culture, a Mössbauer study

Mössbauer investigations between 4.5 and 300 K of iron minerals formed during the growth of the binary culture containing two anaerobic alkaliphilic bacteria-dissimilatory iron-reducing Geoalkalibacter ferrihydriticus (strain Z-0531) and organotrophic Anaerobacillus alkalilacustre (strain Z- 0521), have been carried out. Mannitol (2 g/l) as the sole substrate with amorphous Fe(III) hydroxide at final concentration 10 or 100 mM were added to the mineral medium. The formation of siderite and probable magnetite or a mixture of magnetite and maghemite were observed.     

Experimental investigations of local heat fluxes on a sphere and on the spherical blunt end of an axisymmetric body

This article presents the results of experimental investigations of local heat transfer on a sphere and on the spherical blunt end of axisymmetric bodies in a flow of low-density gas. The data were obtained in the region of Mach numbers from 3.3 to 8, at Reynolds numbers from 5 to 2.6·10³.     

Multistep flow-membrane filtration,gel-permeation chromatography,and spectrophotometric determination of polydisperse compounds

To determine the molecular weight distribution of natural polydisperse compounds (peat humic acids) and synthetic substituted polyvinyls, membrane filtration, gel-permeation chromatography, and spectrophotometric determination procedures were developed. The determination limit of polyvinyls was 0.1–0.2 mg/mL. The absorbance of polyvinyl solutions was a linear function of the concentration over the range 0.1–6.0 mg/mL. It was found that the size-fraction distributions of both humic substances and substituted polyvinyls depended not only on the molecular weight, but also the molecular conformation.     

Potential of capillary zone electrophoresis for estimation of humate acid-base properties

Capillary zone electrophoresis (CZE) has been applied for fractionation and characterization of soil-derived humic acids (HAs). Humic acids from soddy-podzolic (HA(s)) and chernozem (HA(ch)) soils were studied as well as hydrophobic high-molecular-weight (HMW) and hydrophilic low-molecular-weight (LMW) HA(s) fractions obtained by salting-out with ammonium sulfate at a saturation of 0-40% and >70%, respectively. The possibility of CZE partial fractionation of HAs has been demonstrated. The shape of "humic hump" was shown to depend on the pH of running electrolyte. Almost the whole peak overlapping occurred if alkaline solutions were used for fractionation, but the peak resolution was improved at pH 5-7. Under appropriate fractionation conditions (pH 7), at least three humic acid subfractions with different electrophoretic mobilities were distinguished in the electropherograms of initial HA and HA(s) fractions. Such a high peak resolution has never been achieved for humic acids before. The presence of three subfractions in the HA is in agreement with gel-filtration analysis and was confirmed by comparison of the electrophoretic behavior of HA(s) with those of its HMW (hydrophobic) and the LMW (hydrophilic) fractions. The potentiometric titration of HA and its fractions was performed and the pK(a) of the functional groups were calculated. An attempt was made for the first time to relate the variation of electrophoretic mobility values with acid-base properties of humic acids. It was shown that changes in the humate charge resulting from the variation of the ionization degree of its functional groups as a function of pH can be estimated on the basis of electrophoretic mobility values. Potential of CZE in estimation of HA isoelectric point was demonstrated. The pH value corresponding to the lowest absolute electrophoretic mobility value of about 20 x 10(-5) cm(2) V(-1) s(-1) can be used for approximate estimation of HA isoelectric point. The data were discussed and agreement with the random coil structural model has been shown.     

Measurement of the <Superscript>14</Superscript>C Content in Liquid Scintillators by Means of a Small-Volume Detector in the Low-Background Chamber of the Baksan Neutrino Observatory

A setup for measuring natural-radioactivity backgrounds and ultralow concentrations of the isotope ¹⁴C in samples of a liquid organic scintillator was created at the low-background laboratory of the Baksan Neutrino Observatory (Institute for Nuclear Research, Russian Academy of Sciences) at a depth of 4900 mwe. The concentration of the radiocarbon ^14C in a sample of a scintillator based on domestically produced linear alkylbenzene was measured, and it was found that ¹⁴C/¹²C (3.3 ± 0.5) × 10^?17.     

Description of small-angle neutron scattering data for nickel–chromium–aluminum alloy within quantum mechanics and classic polydisperse sphere model

The modified Yukawa potential is used to fit the nucleus model parameters to the data on small-angle neutron scattering on nickel—chromium—aluminum alloy for the product of the transferred momentum Q and the effective nucleus radius R, satisfying the condition QR ≤ ?. The analytical polydisperse sphere model is used to calculate the neutron scattering intensity and to determine the most probable macroscopic sphere radius R ₀ at QR ₀ ≥ 3?.     

On the Negatively Charged Layer of the Earth’s Electric Field

Based on the hydridic Earth model, we propose a hydridic model of the Earth’s electric field. The model predicts that the negative electrode of the Earth’s capacitor is located under the Earth’s crust and the Earth’s fluids carry a positive charge. We have observed an excess of positive charge in the Earth’s crust down to kilometer depths. The model explains the unitary variation of the fair-weather atmospheric electric field strength, the change in atmospheric electric field strength and the precipitation of high-energy electrons during earthquakes.     

Study of the structure of neutron halo using neutron transfer reaction

To estimate the probability of two-neutron configurations in halo nuclei, we propose an experimental method of studying neutron-neutron correlations at periphery of such nuclei by measuring two-neutron transfer reaction. The experimental study of ⁶He + A ↦ ⁴He + B for various targets is performed using ⁶He beam of Flerov Laboratory of Nuclear Reactions (JINR, Dubna) at energy of about 15 MeV/u and technique of nuclear photoemulsions. Searching for events of two-nucleon transfer reaction and their processing is performed using the PAVICOM-setup at P.N. Lebedev Physical Institute.