Potentiometric estimation of the stability constants of ion-lonophore complexes in ion-selective membranes by the sandwich membrane method: theory, advantages, and limitations.

Segmented sandwich membrane method of studying stoichiometry and stability constants of ion-ionophore complexes in ion-selective membranes is considered in detail. The experimental data (reported earlier in Russian) concerning complexes of various ions with valinomycin, with H+-selective neutral ionophore hexabutyltriamidophosphate, and with anion-binding neutral ionophore p-hexyl trifluoroacetylbenzoate is presented in a compact form. Advantages of titration technique in the sandwich membrane method (the presence of an internal criterion of reliability, and the possibility of direct determination of complex stoichiometry coefficients) are specially addressed.

Calculation of the anomalous exponents in the rapid-change model of passive scalar advection to order epsilon(3).

The field theoretic renormalization group and operator product expansion are applied to the model of a passive scalar advected by the Gaussian velocity field with zero mean and correlation function approximately equal to delta(t-t('))/k(d + epsilon). Inertial-range anomalous exponents, identified with the critical dimensions of various scalar and tensor composite operators constructed of the scalar gradients, are calculated within the epsilon expansion to order epsilon(3) (three-loop approximation), including the exponents in anisotropic sectors. The main goal of the paper is to give the complete derivation of this third-order result, and to present and explain in detail the corresponding calculational techniques.

Anomalous scaling, nonlocality, and anisotropy in a model of the passively advected vector field.

A model of the passive vector quantity advected by the Gaussian velocity field with the covariance approximately delta(t-t('))|x-x(')|(epsilon) is studied; the effects of pressure and large-scale anisotropy are discussed. The inertial-range behavior of the pair correlation function is described by an infinite family of scaling exponents, which satisfy exact transcendental equations derived explicitly in d dimensions by means of the functional techniques. The exponents are organized in a hierarchical order according to their degree of anisotropy, with the spectrum unbounded from above and the leading (minimal) exponent coming from the isotropic sector.

Influence of modified gravity on growth and structure of Vaucheria sessilis (Xanthopyceae).

The constant presence of gravity force in the evolution of life on Earth caused the adaptation for its pressure and dependence of growth and morphogenesis of high plants on gravity, and appearance of gravitaxises of unicellular organisms. The modern investigations demonstrated the ability even of prokaryotic organisms for sensitivity of gravity modifications Erdmann et al., 1997).

Heterogeneous condensation in dense media.

A theoretical description of heterogeneous nucleation kinetics is presented. This description takes into account the perturbation of the vapor phase initiated by the growing droplets. The form of the density profile around the growing droplet is analyzed and some special approximations are given.

Anomalous scaling in two models of passive scalar advection: effects of anisotropy and compressibility.

The problem of the effects of compressibility and large-scale anisotropy on anomalous scaling behavior is considered for two models describing passive advection of scalar density and tracer fields. The advecting velocity field is Gaussian, delta correlated in time, and scales with a positive exponent epsilon. Explicit inertial-range expressions for the scalar correlation functions are obtained; they are represented by superpositions of power laws with nonuniversal amplitudes and universal anomalous exponents (dependent only on epsilon and alpha, the compressibility parameter).

Anomalous exponents to order epsilon 3 in the rapid-change model of passive scalar advection.

Field-theoretic renormalization group is applied to the Kraichnan model of a passive scalar advected by the Gaussian velocity field with the covariance -~delta(t-t('))|x-x(')|(epsilon). Inertial-range anomalous exponents, related to the scaling dimensions of tensor composite operators built of the scalar gradients, are calculated to the order epsilon(3) of the epsilon expansion. The nature and the convergence of the epsilon expansion in the models of turbulence are briefly discussed.

Anomalous scaling of a passive scalar in the presence of strong anisotropy.

Field theoretic renormalization group and the operator product expansion are applied to a model of a passive scalar quantity straight theta(t,x), advected by the Gaussian strongly anisotropic velocity field with the covariance infinity delta(t-t('))/x-x(')/(epsilon). Inertial-range anomalous scaling behavior is established, and explicit asymptotic expressions for the structure functions S(n)(r) identical with<[straight theta(t,x+r)-straight theta(t,x)](n)> are obtained. They are represented by superpositions of power laws; the corresponding anomalous exponents, which depend explicitly on the anisotropy parameters, are calculated to the first order in epsilon in any space dimension d.

The electronic structure and spectra of Ru(II) and Ru(III) complexes with imidazole and its derivatives.

The calculations of the electronic structure and spectra of [Ru(NH3)5L]2+ (L = imidazole, histidine) and [Ru(NH3)5L]3+ (L = imidazole, N-imidazolate anion, 4-methylimidazole, 4-methyl-1N-imidazolate anion and 1N-bound histidine) complexes are performed in the framework of the CI method in the INDO/CNDO approximation. The MO diagram is obtained. The assignment of all transitions with energies of 4-5 eV is made and the nature of corresponding excited states is discussed.

Manifestation of anisotropy persistence in the hierarchies of magnetohydrodynamical scaling exponents.

An example of a turbulent system where the failure of the hypothesis of small-scale isotropy restoration is detectable both in the "flattening" of the inertial-range scaling exponent hierarchy and in the behavior of odd-order dimensionless ratios, e.g., skewness and hyperskewness, is presented.

Persistence of small-scale anisotropies and anomalous scaling in a model of magnetohydrodynamics turbulence.

The problem of anomalous scaling in magnetohydrodynamics turbulence is considered within the framework of the kinematic approximation, in the presence of a large-scale background magnetic field. The velocity field is Gaussian, delta-correlated in time, and scales with a positive exponent xi. Explicit inertial-range expressions for the magnetic correlation functions are obtained; they are represented by superpositions of power laws with nonuniversal amplitudes and universal (independent of the anisotropy and forcing) anomalous exponents.

Modeling of divalent/monovalent ion selectivity of ion-exchanger-based solvent polymeric membranes doped with coexchanger.

It is shown that the addition of a coexchanger does not always improve the selectivity of an ion-selective electrode. As a model case, the selectivity toward divalent primary ions I2+ in the presence of monovalent interference J+ is numerically simulated for membranes based on ion-exchanger R- and doped with a coexchanger (ionic additive) S+. It is, for the first time, demonstrated that the addition of a coexchanger, together with a high mobility of ion-exchanger sites, may be either beneficial or harmful to selectivity.

Isolation and characterisation of chemotactic mutants of Chlamydomonas reinhardtii obtained by insertional mutagenesis.

The swimming behaviour of the green flagellated protist Chlamydomonas reinhardtii is influenced by several different external stimuli including light and chemical attractants. Common components are involved in both the photo- and chemo-sensory transduction pathways, although the nature and organisation of these pathways are poorly understood. To learn more about the mechanism of chemotaxis in Chlamydomonas, we have generated nonchemotactic strains by insertional mutagenesis.

A highly repeated FCP centromeric sequence from chaffinch (Fringilla coelebs: Aves) genome is revealed within interchromosomal connectives during mitosis.

A highly repeated FCP (Fringilla coelebs PstI element) sequence was localized by FISH in centromeric regions of all chromosomes of the chaffinch. Besides, FISH signal was found also in interchromosomal connectives linking centromeres of non-homologous chromosomes in mitotic cells. The presence of DNA in the connectives was confirmed by immunostaining with anti-dsDNA antibodies as well as in experiments on nick-translation and random primed labeling in situ.

IR spectra of CH3F in liquid and solid noble gas solutions.

The IR absorption spectra of CH3F doped Ar, Kr and Xe solutions have been recorded near the melting point. The full widths at half maximum of fundamental bands increase noticeably after crystallization of the Xe and Kr solutions. A slight narrowing of the bands is observed just below the freezing point of the Ar solution.

Metal arrays in structural units based on anion-centered metal tetrahedra.

Structural units based on anion-centered metal tetrahedra (XA(4); X = O, N; A = metal) are described as eutactic metal fragments with anions in tetrahedral interstices. In this respect these units may be subdivided into fluorite derivatives and units based on stellae quadrangulae (tetrahedral stars). To describe the geometry of the metal arrays a set of tetrahedrally packed metal radii, r(tp), is derived for A = Cu, Pb, Bi, and some rare-earth metals from the systematic analysis of the A.

[The specific blocks of heterochromatin on metaphase chromosomes of horse and Prjewalski horse detected by in situ digestion with restriction endonucleases].

Restriction endonuclease in situ digestion of metaphase chromosomes gives an opportunity to reveal strips with different structure within GC-rich pericentric heterochromatin of the domestic horse and the wild Przewalski horse. Blocks of heterochromatin, which are insensitive to HaeIII and brightly stained with chromomycin A3 after restriction enzyme digestion, are localized on the border with euchromatin in the majority of chromosomes of Equus caballus and E. przewalskii.

Relative retention times of chlorinated monoterpenes.

GC retention times for 67 chlorinated monoterpenes, belonging to the technical pesticide Toxaphene have been measured under the same conditions and relative retention times have been determined. They consisted of 45 chlorinated bornanes, 13 chlorinated bornenes, 8 chlorinated dihydrocamphenes and 1 chlorinated camphene. Useful correlations between structure and retention time were found.

[Thermostability of DNA and its connection with the glassing process].

Using differential scanning calorimetry, the thermal denaturation of calf thymus DNA with different content of water (from 12 to 92%) was investigated. Dependences of melting temperature and enthalpy on the biopolymer hydration degree were established. Within the range of water concentrations from 92 to 50% the values of thermodynamic parameters of denaturation were obtained being in good agreement with the published data.

[Interaction of the regulatory region of the tryptophan oxygenase gene with transcription factors of the nuclear factor 1 (NF1) family].

Inducible hormone-dependent tryptophan oxygenase gene is expressed mostly in the liver under the control of glucocorticoid hormones. In the regulatory region of this gene there are three constitutive sites independent of hormone presence and gene expression. While investigating transcription factors responsible for the formation of specific chromatin structure in the regulatory region of inducible genes it is necessary to identify proteins which can bind to DNA specifically in these sites.

[Theory of integrating cellular tension and consequences from it].

Tensegrity model and implications from it have been reviewed. Experimental data confirming the model are shown. While signal vectorization is well confirmed and well depicted by the model, the vectorization of expression implied by the model has not yet been elaborated.

[DNA-dependent RNA polymerase I from human placental nuclei].

This paper describes a large-scale method for solubilisation and purification of DNA-dependent RNA-Polymerase I from mature human placenta. The solubilisation method involves homogenization of the whole human placenta, isolation of cell nuclei, sonication of separated nuclei at high ionic strength and ammonium sulfate precipitation. The purification method consists of chromatography of RNA-Polymerase I activity on DEAE-Sephadex A-25 and Phosphocellulose P-11, and glycerol-density gradient centrifugation.

Two Coordination Modes of CO in Zeolites: A Temperature-Dependent Equilibrium.

CO interacts with exchangeable cations M (gray spheres in the picture) of zeolites to form M ⋅⋅⋅CO and M ⋅⋅⋅OC species (C: black; O: white) which are in a temperature-dependent equilibrium. For Na-ZSM-5 (M =Na ) the difference in interaction energy amounts to 3.8 kJ mol , as determined by means of variable-temperature FT-IR spectroscopy.

[Role of protein kinase C in the regulation of Ca-responses induced by purinergic agonists and thapsigargin in rat peritoneal macrophages].

The effect of protein kinase C activating phorbol ester, phorbol-12-myristate-13-acetate (PMA), on purinergic agonists- and thapsigargin-induced Ca2+ signals in Fura-2 loaded rat peritoneal macrophages was investigated. PMA (100 ng/ml) was shown to inhibit 200 muM ATP- or 200 microM UTP-evoked Ca2+ entry in macrophages. Protein kinase C activation by PMA also inhibits the store-dependent or "capacitative" Ca2+ influx stimulated by emptying the intracellular Ca2+ stores with endoplasmic Ca(2+)-ATPase inhibitor thapsigargin (0.

[Effect of inhibitors of mitochondrial oxidative metabolism on Ca-responses induced by purinergic agonists and thapsigargin in rat peritoneal macrophages].

Effects of two metabolic inhibitors, oligomycin and carbonyl cyanide m-fluorophenylhydrazone (FCCP), on Ca2+ signals induced by purinergic agonists and thapsigargin in Fura-2-loaded rat peritoneal macrophages was investigated. 1 microgram/ml oligomycin or 1 microM FCCP were shown to inhibit 200 microM ATP or 200 microM UTP-evoked Ca2+ entry in macrophages. Independently of their chemical structure and site of inhibition, both metabolic poisons also inhibit the store-dependent or "capacitative" Ca2+ influx stimulated by emptying the intracellular Ca2+ stores with endoplasmic Ca(2+)-ATPase inhibitor thapsigargin (0.