Biomedical subjects
Publications and source records attributed to V P Romanov.
The most frequent clinical manifestation of renal lesion in patients with paraneoplastic syndrome is nephrotic syndrome, which is associated with a special morphological type of renal lesion, membranous nephropathy (MN). The latter accompanies various types of cancer. The article contains case reports of patients with paraneoplastic MN, which was coped with after radical antitumoral treatment.
We consider the problem of light scattering in a slab of cholesteric liquid crystal with the pitch which significantly exceeds the wavelength of light. The electromagnetic wave propagation and the Green's function are investigated for this medium basing on geometric optics approximation. The correlation function of the director fluctuations is calculated with the aid of the vector analog of the WKB approximation. A general approach to treatment of single light scattering in a stratified medium with smoothly varying properties based on the Kirchhoff method is developed. Angular and polarization dependencies of the single light scattering intensity as well as extinction of the mean field are analyzed. Unusual dependence of the light scattering intensity on the size of the system is found.
Dynamic properties and layer displacement-layer displacement correlation functions of the smectic-A films on a substrate are investigated. The eigenfrequencies spectrum and eigenmotions of the film are calculated within the framework of a discrete model. It was found that the static as well as dynamic properties of freely standing and solid supported smectic-A films differ significantly. In particular, the acoustic mode is absent in the films on a substrate and the surface tension is not essential for the film dynamics. The correlation length of the spatial layer displacement correlation functions is finite for films on a substrate in contrast to the free standing films. An effect of thermal fluctuations on the specular and diffuse x-ray scattering was analyzed.
The consequent description of the x-ray scattering from the free standing smectic-A films is suggested. Calculations are based on the discrete model for the film dynamics. The scattering intensity temporal autocorrelation function is obtained within the framework of this approach neglecting the multiple scattering and refraction effects. It is shown that the behavior of this function crucially depends on the film thickness. In particular, in thin films containing less than 10(3) layers the time dependence of has damping oscillation character. This behavior is determined by an acoustic mode that describes the film motion caused by the action of the surface tension. For thick films containing more than 10(4) layers the dynamics of the intensity temporal autocorrelation function is determined either by an acoustic mode or by a wide spectrum of modes depending on the x-ray geometry. In both the cases the autocorrelation function is a relaxation one. The results obtained are compared with the experiments on the coherent soft and hard x-ray scattering.
An exact solution for the boundary problem of temporal correlations of light multiply scattered from a medium occupying a half space is found by means of the Wiener-Hopf method, taking into account single-scattering anisotropy. Within the P1 approximation a universal initial decay rate of the temporal correlation function is obtained. For larger time intervals a higher single-scattering anisotropy yields a higher decay rate contrary to predictions of the diffusion approximation. Within the P2 approximation, which takes account of the first- and second-order Legendre polynomials, the solution obtained becomes universal in an expanded temporal range and agrees rather well with the known measurement data.
The eigenvibrations and time-dependent layer displacement-layer displacement correlation functions are analyzed in a free-standing thin smectic-A films with the help of a discrete layer model. The film motions are described using the Chebyshev polynomials of second kind, U(n)(x). The eigenfrequencies problem is essentially simplified within the framework of this approach since the numerical solution of the high degree algebraic characteristic equation is replaced by the analytical solution of a rather simple trigonometrical equation. The dependences of eigenmodes on wave number q(perpendicular) were analyzed. For small q(perpendicular) one mode is a low frequency acoustic wave and other modes are high frequency optical oscillations. As the wave number q(perpendicular) increases all modes successively turn into relaxation when starting with the acoustic mode. The rather simple expression for susceptibility matrix and for spectral densities of layer displacement correlation functions were obtained using the Chebyshev polynomials. It was shown that the frequency dependences of spectral densities are sensitive to wave number q(perpendicular). For small q(perpendicular) the spectral densities of displacement-displacement correlation functions have a sharp peak and for large q(perpendicular) they turn into a contours of Lorentzian type.
Plasmid pBS195, detected in a strain of Lactobacillus sp. isolated from long-living persons, has a broad host range, including Gram-positive and Gram-negative microorganisms [1]. Plasmid-harboring colonies of the strain Escherichia coli HB101 give a color reaction with catechol. This indicates that genes mediating the activity of oxygenase are present in this plasmid. The high activity level of this enzyme, mediated by pBS195, and substrate specificity, which has not bee detected in any known metapyrocatechases, were found in cells of E. coli. Hybridization with a 32P-labeled fragment containing the NahC gene revealed a region of homology with a 1.6-kb EcoR I- BamH I fragment of plasmid pBS195. Deletion variants of this plasmid that lost oxygenase activity confirmed the location of the oxygenase gene in this region. The gene responsible for oxygenase activity in the plasmid was cloned on the pUC19 vector in E. coli cells. The expression of the cloned gene is controlled by the lac promoter of this vector. Physical, hybridization, and deletion analyses as well as analysis of polypeptides, which are synthesized in E. coli mini-cells, showed that this activity requires the participation of a polypeptide with molecular mass of 34 kDa.
A study of 80 patients with spinal osteochondrosis and 27 patients with osteochondrosis deformans revealed high efficacy of treatment at the "Marcial Waters" health results (Karelian SSR). The authors developed methods of analgesiometry permitting to evaluate objectively treatment results.
Dichotic stimulation with binaurally presented click trains at time-varying interaural differences of stimulation caused a pronounced sensation of fused image (FI) movement in man. Threshold click rate in the trains needed for the FI movement sensation during variations of interaural time differences of stimulation equalled 7.6 Hz and during variations of interaural intensity differences it equalled 9.6 Hz. When FI movement velocity ranged from about 20 to 120 degrees/s with changing interaural intensity of stimulation, differential threshold for FI movement velocity increased from 2 to 12 degrees/s. Relative differential thresholds of the perception of FI movement velocity were essentially independent of the velocity. Subjective scales of FI movement velocity perception could be basically approximated by linear relations y = AX, y = A(X-X0). The scale slopes appeared to be significantly different during fractionation and multiplication procedures.
On the basis of an analysis of remote results of a tight suture of the common bile duct within the period of from 1,5 to 20 years in 115 of 230 patients the authors describe indications and contraindications to this variation of finishing choledochotomy. Good remote results were obtained in 75,6% of patients, satisfactory results--in 9,5% and bad results in 14,8%.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The scheme of the formation of structural chromosome mutations, based on hydrogen binding of double-stranded DNA in the sites of palindrome sequencies is proposed. According to this scheme the mutagen damage in palindromes, forming chromosome loops, leads to the formation of structural mutations. In lack of contact between double-stranded regions of chromosomes the restoration of its structure occurs. The molecular mechanism of the formation of structural chromosome mutation is considered from the point of view of repair hypothesis and explains the gene position effect.
Explore the source record for details and available documents.
When seeds of Crepis capillaris were germinated in solutions of Cu(NO3)2 (at 0.55-10(-5) M and 1.1-10(-5) M concentrations) the frequency of structural chromosome mutations induced by gamma-rays (137Cs) at 200 and 400 r doses was higher as compared to that induced in the absence of copper ions.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.