Search

The influence of non-opsonized and opsonized S. aureus 2879M and E. coli 321 strains on the total strength of interaction between the endothelial cell and neutrophil during the docking process was studied using in vitro model of experimental septicemia. We observed a decrease in the force and work of adhesion between receptors of neutrophils and endothelial cells under the influence of non-opsonized strains and further decrease in the affinity of single interactions between cells under the influence of opsonized S. aureus, which was compensated by an increase in the number of contacts, as well as an increase in the force of adhesion under the influence of opsonized E. coli compared to non-opsonized bacteria, which remained below the control level, while adhesion work reaches the control level. Thus, opsonization of S. aureus aggravates the "immunological uncoupling" between neutrophils and endothelial cells, while opsonization of E. coli reduces the pathological effect compared to non-opsonized bacteria. [ABSTRACT FROM AUTHOR]

A two-section analytical chamber was developed and tested for study of EA.hy926 endothelial cells culture in real time with high resolution. It has been shown that the method of scanning ion-conductance microscopy yields relevant results, since it ensures the absence of mechanical effects on cells, and allows to scan endothelial cells on membranes that ensures that cells are surrounded by a nutrient medium. The method made it possible not only to visualize changes in the cell surface during long-term scanning, but also to detect extracellular (microfilaments) and intracellular (nucleolus) structures. The creating of a rigidity map allowed it to be estimated that the mean rigidity of endothelial cell membranes was in the range from 357 to 796 Pa. After 240 min from the start of observation, the endothelial cells began to produce apoptotic bodies, wherein the rigidity of the cells gradually increased and the rigidity of the apoptotic bodies decreased. [ABSTRACT FROM AUTHOR]

Background: The purpose of this review is to summarize our own experimental studies carried out over a 13-year period of time using the F98 rat glioma as model for high grade gliomas. We evaluated a binary chemo-radiotherapeutic modality that combines either cisplatin (CDDP) or carboplatin, administered intracerebrally (i.c.) by means of convection-enhanced delivery (CED) or osmotic pumps, in combination with either synchrotron or conventional X-irradiation. Methods: F98 glioma cells were implanted stereotactically into the brains of syngeneic Fischer rats. Approximately 14 days later, either CDDP or carboplatin was administered i.c. by CED, followed 24 h later by radiotherapy using either a synchrotron or, subsequently, megavoltage linear accelerators (LINAC). Results: CDDP was administered at a dose of 3 µg in 5 µL, followed 24 h later with an irradiation dose of 15 Gy or carboplatin at a dose of 20 µg in 10 µL, followed 24 h later with 3 fractions of 8 Gy each, at the source at the European Synchrotron Radiation Facility (ESRF). This resulted in a median survival time (MeST) > 180 days with 33% long term survivors (LTS) for CDDP and a MeST > 60 days with 8 to 22% LTS, for carboplatin. Subsequently it became apparent that comparable survival data could be obtained with megavoltage X-irradiation using a LINAC source. The best survival data were obtained with a dose of 72 µg of carboplatin administered by means of Alzet® osmotic pumps over 7 days. This resulted in a MeST of > 180 days, with 55% LTS. Histopathologic examination of all the brains of the surviving rats revealed no residual tumor cells or evidence of significant radiation related effects. Conclusions: The results obtained using this combination therapy has, to the best of our knowledge, yielded the most promising survival data ever reported using the F98 glioma model. [ABSTRACT FROM AUTHOR]

The incubation of quantum dots with lymphocytes induced significant changes in all morphometric characteristics of these cells. Protein crown formed on the surface of quantum dots after incubation with the serum consists mainly of transport proteins, immunoglobulins, blood coagulation proteins, and kininogens. Protein crown changes the morphometric characteristics of cells: in the case of incubation with quantum dots that have low-molecular-weight coating, a shift towards control parameters (cells without exposure) was observed; on the contrary, after incubation with quantum dots that have a high-molecular-weight coating, the differences from the control became more pronounced. It can be hypothesized that protein crown provokes autoagression of lymphocytes against each other and against platelets. [ABSTRACT FROM AUTHOR]

Abstract—Atomic force microscopy was used to create a system for measuring intercellular adhesion. Scanning electron microscopy was applied to confirm that poly-L-lysine is the best substance for fixation of neutrophils and lymphocytes on the probe. It was shown that when one cell is fixed on the probe and the other one is fixed on the substrate surface it is possible to carry out relevant measurements of intercellular adhesion forces by FS spectroscopy. The intercellular adhesion forces of neutrophils and lymphocytes were measured. The adhesion forces of neutrophils and lymphocytes were 38.5 ± 13.7 pN and 35.6 ± 8.3 pN, respectively. Thus, adhesion of neutrophils is statistically significantly higher than adhesion of lymphocytes. [ABSTRACT FROM AUTHOR]

We propose the structure of the solution of the problem of thermoelasticity for a long cylinder containing a thin subsurface layer with reduced parameters of heat transfer and heat capacity varying as functions of time under the conditions of heating by heat sources whose intensity is also a function of time varying and in the process of cooling by the environment. For the temperature of the cylindrical surface appearing in the structure of the solution, we deduce an integrodifferential equation with variable coefficients and the Volterra-type integral operator. The scheme of the spline approximation method is adapted for its solution. We analyze the temperature and stress distributions in time both on the surface of the cylinder and at different depths depending on the given regularities of changes in the intensity of heat sources and reduced thermophysical parameters of the subsurface layer. We consider the possibility of choosing variable thermophysical parameters partially compensating the action of time-dependent heat sources. [ABSTRACT FROM AUTHOR]

We develop a method for the solution of boundary-value problems of the thermostressed state of cylindrical bodies with thin near-surface layers having time-dependent thermophysical properties. The presence of a thin near-surface layer in a long solid cylinder is taken into account in the formulated boundary-value problem by means of a nonclassical nonstationary boundary condition with variable coefficients. The replacement of this condition by the classical first-kind condition enables one to reduce the original problem to finding the solution of an integro-differential equation with variable coefficients. This equation has a Volterra-type integral operator and is solved by using spline approximations. The efficiency of this method has been partially verified on the well-known problem of heating of a thin homogeneous plate with variable Biot number by environment. We investigate the thermostressed state of a cylinder for both linear and exponential normalized surface parameters of heat transfer and heat capacity over time. For different stages of heating, we analyze at what constant values of parameters the thermal regime of the cylinder is closest to the mode with variable parameters. The obtained solutions and data on their properties can be used in solving the problems of boundary parametric identification. [ABSTRACT FROM AUTHOR]

We have used a self-consistent version of the BCS + RQRPA method for a systematic study of the two-neutrino double-beta-decay of nuclei with 100 < A ≤ 150. The comparison with other approaches, namely the QRPA and the RQRPA, shows that inclusion of the quasiparticle correlations at the BCS level reduces the ground-state correlations in the particle-particle channel of the proton-neutron interaction. This in turn results in a systematic reduction of the double-beta-decay matrix elements. The effect of the extension of the formalism on the Ikeda sum rule has been discussed. [ABSTRACT FROM AUTHOR]

We have used a self-consistent version of the BCS + RQRPA method for a systematic study of the double-beta decay of medium-heavy nuclei with 70 ≤ A ≤100. The results have been compared with the previously used approaches, namely the QRPA and the RQRPA approximations. We have shown that inclusion of the quasiparticle correlations at the BCS level reduces ground state correlations in the particle–particle channel of the proton–neutron interaction, resulting in a systematic reduction of the double-beta-decay matrix elements. We also simplified the RQRPA equations significantly obtaining a low-dimensioned set of linear equations for the quasiparticle densities. [ABSTRACT FROM AUTHOR]

A new analysis of the renormalized proton–neutron quasiparticle random phase approximation based on simultaneous recalculation of the one-body density matrix and the pairing tensor has been used to study the double beta decay. We demonstrated that inclusion of the quasiparticle correlations at the BCS level reduces ground state correlations in the particle–particle channel of the proton–neutron interaction. We also simplified the RQRPA equations significantly obtaining a low-dimensioned set of linear equations for the quasiparticle densities. The formalism was applied to the double beta decay of 76Ge. [ABSTRACT FROM AUTHOR]

The distribution of interstitial impurities between liquid lithium and solid titanium-alloyed vanadium is investigated. It is shown that titanium alloying of vandium intensifies nitrogen and carbon transport from lithium into the solid metal. At the same time, the concentration of oxygen in the surface layers of the specimens increases as a result of penetration of lithium and formation of complex oxides of the MeLiO type. Increase in the titanium content leads to an increase in the carbon concentration on the surface and to the formation of protective carbon films that inhibit the diffusion of interstitial impurities into deep-seated layers. [ABSTRACT FROM AUTHOR]

The activity of ATP-glucokinase and of polyphosphate glucokinase was examined during growth of the actinomycete Streptomyces aureofaciens 8425 under conditions of intense chlortetracycline (CTC) synthesis. ATP-glucokinase was active in the strain only during the logarithmic phase of culture growth; the activity of polyphosphate glucokinase appears only at the end of the logarithmic phase of growth and rises in parallel with the rate of CTC biosynthesis in the stationary phase. During the rise of activity of polyphosphate glucokinase and of CTC biosynthesis the cells accumulate sugar phosphates, mainly glucose-6-phosphate. It appears that the biosynthesis of CTC in Streptomyces aureofaciens takes place at the expense of glycolysis, using up the high-energy phosphate of high-molecular polyphosphates. [ABSTRACT FROM AUTHOR]

The collective hamiltonian for the axial quadrupole vibrations was derived from the QQ+PP model. The generator coordinate method was applied and the results obtained through the symmetric moments expansion and the gaussian overlap approximation were compared. It was found that the collective potential and the average magnitude of the mass parameter obtained in both approximations are close to each other. [ABSTRACT FROM AUTHOR]

By using a metric approach, we study the problem of well-posedness of boundary-value problems for hyperbolic equations of order n ( n≥2) with constant coefficients in a cylindrical domain. Conditions of existence and uniqueness of solutions are formulated in number-theoretic terms. We prove a metric theorem on lower estimates of small denominators that appear when constructing solutions. [ABSTRACT FROM AUTHOR]