Recombinant Fragment of the Extracellular Domain of Human Desmoglein 3 Fused with the Fc-Fragment of Human IgG1 Selectively Adsorbs Autoreactive Antibodies from the Sera of Pemphigus Patients.

Using the recombinant second fragment of the extracellular domain (EC2) of human desmoglein type 3 (Dsg3) as an affinity ligand, an immunosorbent was obtained that selectively binds autoreactive antibodies to this domain from the immune sera of patients with pemphigus. The EC2 protein was obtained in the form of a fusion protein with the Fc-fragment of human IgG1. The production was carried out in CHO cells using the method of transient expression.

Experimental study of homogeneous nucleation from the bismuth supersaturated vapor: evaluation of the surface tension of critical nucleus.

The homogeneous nucleation of bismuth supersaturated vapor is studied in a laminar flow quartz tube nucleation chamber. The concentration, size, and morphology of outcoming aerosol particles are analyzed by a transmission electron microscope (TEM) and an automatic diffusion battery (ADB). The wall deposit morphology is studied by scanning electron microscopy. The rate of wall deposition is measured by the light absorption technique and direct weighting of the wall deposits. The confines of the nucleation region are determined in the "supersaturation cut-off" measurements inserting a metal grid into the nucleation zone and monitoring the outlet aerosol concentration response. Using the above experimental techniques, the nucleation rate, supersaturation, and nucleation temperature are measured. The surface tension of the critical nucleus and the radius of the surface of tension are determined from the measured nucleation parameters. To this aim an analytical formula for the nucleation rate is used, derived from author's previous papers based on the Gibbs formula for the work of formation of critical nucleus and the translation-rotation correction. A more accurate approach is also applied to determine the surface tension of critical drop from the experimentally measured bismuth mass flow, temperature profiles, ADB, and TEM data solving an inverse problem by numerical simulation. The simulation of the vapor to particles conversion is carried out in the framework of the explicit finite difference scheme accounting the nucleation, vapor to particles and vapor to wall deposition, and particle to wall deposition, coagulation. The nucleation rate is determined from simulations to be in the range of 10(9)-10(11) cm(-3) s(-1) for the supersaturation of Bi(2) dimers being 10(17)-10(7) and the nucleation temperature 330-570 K, respectively. The surface tension σ(S) of the bismuth critical nucleus is found to be in the range of 455-487 mN/m for the radius of the surface of tension from 0.36 to 0.48 nm. The function σ(S) changes weakly with the radius of critical nucleus. The value of σ(S) is from 14% to 24% higher than the surface tension of a flat surface.

Spectroscopic and photophysical properties of protonated forms of some fluoroquinolones in solutions.

Electronic absorption and fluorescence spectra of ciprofloxacin, norfloxacin, enoxacin, pefloxacin and nalidixic acid in aqueous solutions were investigated. The time-resolved fluorescence spectra were measured and interpreted. The changes of the luminescence spectra and electron structure of the compounds under study are explained by different degrees of the spin-orbital interaction caused by nitrogen heteroatoms lone pairs effect. Possible ways of the protonation process for naphtyridine and quinolone rings with different substitutions are discussed. The photophysical behavior of FQs was studied using density functional theory (DFT) calculations.

Single dust-particle rotation in glow-discharge plasma.

Rotation of a single dust granule (spin) is investigated experimentally in a stratified glow discharge. We employ the technique of measurement of the angular velocity, which is based on coordinate tracing of the light scattered by a hollow transparent particle. The angular velocity measured in the experiment is about 1-2 orders of magnitude higher than observed in previous experiments. We found that the angular velocity depends linearly on the discharge current. The mechanism of rotation of the granule is also described.

Size-dependent fluorescence of dibenzoylmethanate and ditoluylmethanate of boron difluoride.

Significant differences in the luminescence properties of dibenzoylmethanate and ditoluylmethanate of boron difluoride bulk crystals and microcrystals were detected. The size-dependent blue-to-green colour change of the luminescence is connected with the band intensity redistribution of monomer and excimer luminescence and fluorescence due to interdimer interaction.

Luminescence and reversible luminescence thermochromism of bulk and microcrystals of dibenzoylmethanatoboron difluoride.

Essential differences in the luminescence properties of dibenzoylmethanatoboron difluoride (1) bulk and microcrystals were detected. Analysis of the spectral data showed that in every case the fluorescence spectrum of 1 consisted of three components: monomer fluorescence, excimer fluorescence, and fluorescence related with interdimer interaction. Evolution of luminescence spectra observed with decrease of the crystal size are bound with decrease of monomer fluorescence intensity and considerable growth of intensity of fluorescence related to interdimer interaction. The presence of reversible luminescence thermochromism was discovered for 1: lowering the temperature from 300 to 77 K resulted in essential hypsochromic shift of the luminescence band maximum ( approximately 60 nm) connected with considerable decrease of the distances between the planes of the neighboring molecules ( approximately 0.1 Angstrom) that lead to the weakening of interdimer interaction and intensification of monomer luminescence.

Evaluation of surface tension and Tolman length as a function of droplet radius from experimental nucleation rate and supersaturation ratio: metal vapor homogeneous nucleation.

Zinc and silver vapor homogeneous nucleations are studied experimentally at the temperature from 600 to 725 and 870 K, respectively, in a laminar flow diffusion chamber with Ar as a carrier gas at atmospheric pressure. The size, shape, and concentration of aerosol particles outcoming the diffusion chamber are analyzed by a transmission electron microscope and an automatic diffusion battery. The wall deposit is studied by a scanning electron microscope (SEM). Using SEM data the nucleation rate for both Zn and Ag is estimated as 10(10) cm(-3) s(-1). The dependence of critical supersaturation on temperature for Zn and Ag measured in this paper as well as Li, Na, Cs, Ag, Mg, and Hg measured elsewhere is analyzed. To this aim the classical nucleation theory is extended by the dependence of surface tension on the nucleus radius. The preexponent in the formula for the vapor nucleation rate is derived using the formula for the work of formation of noncritical embryo [obtained by Nishioka and Kusaka [J. Chem. Phys. 96, 5370 (1992)] and later by Debenedetti and Reiss [J. Chem. Phys. 108, 5498 (1998)]] and Reiss replacement factor. Using this preexponent and the Gibbs formula for the work of formation of critical nucleus the dependence of surface tension on the radius R(S) of the surface of tension is evaluated from the nucleation data for above-mentioned metals. For the alkali metals and Ag the surface tension was determined to be a strong function of R(S). For the bivalent metals (Zn, Hg, and Mg) the surface tension was independent of radius in the experimental range. A new formula for the Tolman length delta as a function of surface tension and radius R(S) is derived by integration of Gibbs-Tolman-Koenig equation assuming that delta is a monotonic function of radius. The formula derived is more correct than the Tolman formula and convenient for the elaboration of experimental data. Using this formula the values of delta are determined as a function of R(S) from the experimental nucleation data. It is determined that all the metals considered are characterized by strong dependence of delta on radius; for the bivalent metals delta changes sign.

Rotational motion of dusty structures in glow discharge in longitudinal magnetic field.

The investigation of dust structure formed in glow discharge in an external longitudinal magnetic field with induction up to 400 G applied is presented in this work. The dust structure starts to rotate in the magnetic field. The angular-velocity magnitude is one to two orders larger than one in other discharge types. Its dependence on the magnetic field is nonmonotonic. The rotation direction inverses with an increase of the magnetic induction value up to a certain magnitude B0. In close range of induction around B0 and under certain conditions the rotation of the upper and lower parts of the structure in the opposite direction is observed. Rotation is caused by the ion-drag force. The inversion of rotation direction relates with the change of plasma flows in the area of their formation in stratum with the magnetic field applied. The effect of ion flows was investigated in two additional experiments on the observation of structure rotation onset and on gravity-driven probing of stratum. The angular-velocity unhomogeniety allowed us to investigate shearing and to observe melting of the dust crystal. The correlation functions approach showed the occurrence of structure transformation and its phase transition of the meltinglike type in the magnetic field.

[Neuromyalgic syndrome in children's infections]. / Neiromialgicheskii sindrom pri infektsionnykh zabolevaniiakh u detei.

Neuromyalgic syndrome (NMS) is clinically and electroneuromyographically (ENMG) first-ever described in 50 children aged 2-13. Muscular pains and pains along peripheral nerves occur in post-infection period of acute respiratory viral infections (ARVI), intestinal and parotitoviral infections with transient (in 3-6 days), dysfunction of peripheral nervous system and muscles. NMS is characterized by predominant involvement of lower limb muscles in pathologic process and by rarely developing generalized form. There are 3 types of changes of nerve conductivity and excitability with conductive blocks absence and disturbances regression that enable to distinguish these dysfunctions from ENMG changes in polyneuropathy. Provoked by infection, transitory non-specific inflammatory muscular reaction and functional disorders of nerve conductivity and excitability may be considered as one of the possible mechanisms of NMS development. More than 20 years of clinical and research experience of in neuroinfections clinic, supports the validity of NMS distinguishing among children acute infections for further diagnostic differentiation with polyneuropathy, viral meningitis and ARVI.

[Chromatographic analysis of low molecular weight fraction of cerebrospinal fluid in children with acute neuroinfections]. / Khromatograficheskoe opredelenie sostava nizkomolekuliarnoi fraktsii tserebrospinal'noi zhidkosti pri ostrykh neiroinfektsiiakh u detei.

Low molecular-weight (oligopeptide) fraction of the cerebrospinal fluid was analyzed by high-performance reversed phase liquid chromatography in 30 children with bacterial and viral neuroinfections. The incidence and height of chromathoraphic peaks in bacterial meningitis depended on the disease etiology, stage, and severity. Qualitative and quantitative composition of low molecular-weight fraction of the liquor varied in patients with viral neuroinfections, depending on the severity of the cerebral parenchyma involvement. Differences in chromatographic profiles in complicated and uneventful course of neuroinfections indicate a possible damaging, protective, or regulatory effect of the liquor peptides. These data focus the attention on the role of oligopeptides in the genesis of neuroinfectious process, significance of search for peptide markers, their further isolation, identification, and development of test systems available for clinical application.

Topological nature of the genetic code.

A model for topological coding of proteins is proposed. The model is based on the capacity of hydrogen bonds (property of connectivity) to fix conformations of protein molecules. The protein chain is modeled by an n -arc graph with the following elements: vertices (alpha -carbon atoms), structural edges (peptide bonds) and connectivity edges (virtual edges connecting non-adjacent atoms). It was shown that 64 conformations of the 4-arc graph can be described in the binary system by matrices of six variables which form a supermatrix containing four blocks. On the basis of correspondences between the pairs of variables in matrices and four letters of the genetic code matrices and supermatrix are converted, respectively, into the triplets and the table of the genetic code. An algorithm admitting computer programming is proposed for coding the n -arc graph and protein chain. Connectivity operators (polar amino acids) are assigned to blocks of triplets coding for cyclic conformations (G, A-in the second position), while anti-connectivity operators (non-polar amino acids) correspond to blocks of triplets coding for open conformations (C, U-in the second position). Amino acids coded by triplets differing by the first base have different structures. The third base for C, U and G, A is degenerated. Properties of the real genetic code are in full agreement with the model. The model provides an insight into the topological nature of the genetic code and can be used for development of algorithms for the prediction of the protein structure.

Crystallization of the isobutylphosphocholine-cholesterol-isobutanol (1:3:3) complex and its investigation by X-ray analysis: interaction of phopholipid headgroups with cholesterol.

A crystal complex consisting of the isobutyl analog of phosphatidylcholine (PC) (isobutylphosphocholine), cholesterol, and isobutanol with molecular ratio 1:3:3 was obtained and investigated by means of X-ray analysis. The complex was shown to correspond to the monoclinic system (sp. gr. P2(1)): a=16.994(10), b=11.314(7), c=28.164(15), beta=104.07(3), V=5252.63 A(3), Z=2, D(calc)=1.0273 g/cm(3). The isobutylphosphocholine molecule is the key component of the complex. Pairs of hydrogen bonds are formed between the (-delta)O-P-O(delta-) group of the isobutylphosphocholine molecule and C-OH groups of two cholesterol and two isobutanol molecules. The third molecules of cholesterol and isobutanol are H-bonded with the (-delta)O-P-O(delta-) group of the isobutylphosphocholine molecule via C-OH groups of isobutanol and cholesterol, respectively. The crystal structure is built up by translation of the complex in multiplicate along the two-fold axis in the direction of axis b. It contains bands formed by isobutylphosphocholine molecules alternately changing their direction. They are fixed by virtue of two zones of electrostatic interactions of the type (-delta)O-P-O(delta-)ellipsis(+)N(CH(3))(3) and are more or less parallel to the bc plane. The structure also contains three-layer domains formed by cholesterol molecules perpendicular to isobutylphosphocholine bands. In the direction of the c-axis isobutylphosphocholine bands alternate with the layers of cholesterol molecules herewith reproducing repeated blocks. The obtained structure is compared with that of crystals of phospholipids and cholesterol and its derivatives.

[The topological structure of the genetic code]. / O topologicheskoi strukture geneticheskogo koda.

On the basis of the topological concept of the vicinity of the point, graphs of connectedness for four nitrous bases (L and D tetrahedra) and the topological patterns of doublet and triplet genetic codes were constructed. These topological patterns were isomorphic to Boolean hypercubes B4 and B6, respectively. The resultant structures of the genetic code resembled those obtained earlier in terms of the rhombic variant of the genetic code table, which was constructed on the basis of complementarity of the coding doublets. Specifically, both models assumed the following: (1) when two groups of doublets and quartets of triplets that coded for one amino acid or two amino acids each were transformed into each other according to Rumer's rule (C <--> A, G <--> U), they retained C2 symmetry, and (2) single transitions of nitrous bases changed the structures of the encoded amino acids to the minimum possible extent. A possible mechanism for the origin of the genetic code and the possibility of using the characteristics of the obtained structures to develop the algorithm of prediction of the supermolecular protein structure, read genetic "texts", and refine the functions of amino acids as molecular modules are discussed in terms of the results obtained.

Reconstitution of the zone-block model of biomembranes. 3. Synthesis and investigation of the structure of phosphatidylcholine analog isobutyl-2-(trimethylammonia)ethyl phosphate in its monohydrate crystals and monohydrate complexes with isobutanol.

An isobutyl analog of phosphatidylcholine--isobutyl-2-(trimethylammonia)ethyl-phosphate (IPC)--was synthesized to accomplish the physical reconstitution of the zone-block model of biomembranes. X-ray analysis was used to study the IPC monohydrate (IPC.H2O) crystals grown from water or dimethylformamide with 2% water and the IPC.H2O complex with isobutanol (IPC.H2O.IB) formed by IPC crystallization from isobutanol with 0.5% water. The two compounds were shown to belong to the monoclinic syngony (Sp. gr. P2(l)/a): IPC.H2O-a = 11.075(4), b = 9.679(3), c = 13.921(5) A; beta = 110.61(4) degrees, Z = 4; IPC.H2O.IB-a = 11.370(6), b = 9.397(5), c = 18.12(1) A, beta = 99.42(5) degrees, Z = 4. In IPC.H2O crystals, IPC molecules formed chains due to the system of hydrogen bonds between water molecules and IPC phosphate groups. In turn, ionic bonds between trimethylammonium and phosphate groups of the bipolar heads made these chains to form layers. Another system of ionic bonds (also between -N+(CH3)3 and -O-P = O groups) arranged the layers in a bilayer structure. The bonds were formed between the pairs of molecules oppositely directed and located in neighbouring monolayers. The structure of the bilayer in IPC.H2O.IB crystals was similar. The only difference was the presence of isobutanol molecules between the IPC isobutyl radicals. C-OH groups of isobutanol formed hydrogen bonds with water molecules. However, the interlayer gaps in these two cases differed significantly. In IPC.H2O, the bilayers partially overlapped, whereas in IPC.H2O.IB, they were located at a considerable distance. The structures of the investigated compounds confirm in principle the possibility of the formation of ionic bonds between trimethylammonium and phosphate groups within the bilayer as well as in the interzonal region with apolar radicals that was predicted by the zone-block model of biomembrane. However, the phosphocholine heads were parallel but not perpendicular (as presumed in the model) to the bilayer plane.

Radionuclide production at the Russia State Scientific Center, RIAR.

Radionuclide production capabilities of the Russia State Scientific Center, the Research Institute of Atomic Reactors (RIAR) are reviewed. Radionuclides routinely produced are as follows: transplutonium elements 243Am, 244-248Cm, 249Bk, 249Cf, 252Cf and high specific activity radionuclides 153Gd, 33P, 113,119mSn, 188W, 63Ni, 55,59Fe, 51Cr, 54Mn, 89Sr. Other HSA radionuclides (133Ba, 65Zn, 124Sb, 45Ca, 60Co, 192Ir, 169Yb, 170Tm, 75Se) are also available from RIAR. Besides radioactive preparations RIAR produces ionising neutron (252Cf), gamma (60Co, 192Ir, 75Se, 153Gd) and alpha (244Cm) sources for medicine, industry and research. A short description of the technology developed is presented.