[en] P-glycoprotein (P-gp) has a role in multidrug resistance (MDR) encountered in human cancers. In this study, we used the colchicine-resistant cell line BE(2)-C/CHCb(0.2), a strain of neuroblastoma cell line BE(2)-C, as a model to measure variations of P-gp expression in cells grown in vitro and in vivo. Cells were cultured in the medium supplemented with colchicine. At the beginning of the study the drug was withdrawn and, after 22 days, added back to the culture medium. Cells were harvested at various time points and xenografted in nude mice. P-gp content in cells was measured by self-competitive binding assay and in tumors, by quantitative autoradiography (QAR). Both assays were carried out using ¹²⁵I-labeled monoclonal antibody MRK16, reactive with P-gp. Concentration of P-gp in cells varied from a maximum of 1,361 pmol/g in the presence of colchicine to a minimum of 374 pmol/g in the absence of colchicine in the culture medium. P-gp concentration in the tumors ranged from 929 to 188 pmol/g, which correlated with P-gp content in the cells at the time of their injection in the mice. QAR is an accurate and reliable method to quantify P-gp expression in tumors. Changes in colchicine concentration in the ambient medium of BE(2)-C/CHCb(0.2) cells growing in vitro resulted in a change in phenotype of P-gp expression, which was stable under conditions of in vivo growth over approximately 9 cell divisions in nude mice xenografts. Therefore, P-gp content in xenografts depends only on the level of resistance of the cells at the time of their injection in the mice

[en] Full text of publication follows: The notions of turbulent viscosity V_T and temperature conductivity a_T a are most frequently used to close the set of differential impulse and heat transfer equations in numerical simulation of thermal and hydrodynamic processes in nuclear power reactor channels. To obtain the quantitative values of V_T and a_T, various turbulent models are applied. The fields of the local flow characteristics (velocity, Reynolds stress, heat fluxes and so on) are most often nonmonotonic, which does not enable one to use, for instance, Boussinesq and Fermi relations to determine the heat and impulse exchange coefficients. The paper describes a new method of evaluation of V_T and a_T coefficients in flows and flow paths of engineering devices based on experimental velocity fluctuations. The intensities of velocity fluctuations are the most reliably measured turbulent characteristic of the flow. It is important that no turbulent models need be used according to the proposed method. The method is developed by the example of turbulent flow at the inlet part of the pipe with arbitrary entrance geometry. Data are obtained on the fields of turbulent viscosity V_T and temperature conductivity a_T in the lead-bismuth loop of the proton target in the volumetric power generation section. Use of the obtained data on V_T and a_T in the design code showed agreement between the theoretical and experimental velocity fields in coolant flow. Based on the proposed method, the values of V_T and a_T can be found in liquid flows with zero velocity gradient and flows with high turbulent intensity. (authors)

[en] Single-wall carbon nanotubes (SWCNTs) are only moderately less stable than graphite, and are significantly more stable than their fullerene counterparts. They are 7 kJ mol-1 metastable relative to graphite, and just 5 kJ mol-1 less stable than diamond. Despite striking differences in vibrational dynamics of carbon atoms in SWCNTs and graphite, their thermodynamic properties at room and higher temperatures are dominated by the same set of high energy vibrations, reflected in very similar vibrational entropies. However, the energetics of SWCNT are governed by counter-acting enthalpic contributions of the diameter-dependent strain induced by the roll-up of graphene sheets into tubes and of carbon-carbon bonding at the edges of graphene sheets in the graphite, but not the specifics of phonon density of states (PDOS).

[en] The vibrational density of states (VDOS) for water confined on the surface of rutile-TiO2 nanoparticles has been extracted from low temperature inelastic neutron scattering spectra. Two rutile-TiO2 nanoparticle samples that differ in their respective levels of hydration, namely TiO2 0.37H2O (1) and TiO2 0.22H2O (2) have been studied. The temperature dependency of the heat capacities for the two samples has been quantified from the VDOS. The results from this study are compared with previously reported data for water confined on anatase-TiO2 nanoparticles.