Young's modulus of polyelectrolyte multilayers from microcapsule swelling

We measure Young's modulus of a free polyelectrolyte multilayer film by studying osmotically induced swelling of polyelectrolyte multilayer microcapsules filled with the polyelectrolyte solution. Different filling techniques and core templates were used for the capsule preparation. Varying the concentration of the polyelectrolyte inside the capsule, its radius and the shell thickness yielded an estimate of an upper limit for Young's modulus of the order of 100 MPa. This corresponds to an elastomer and reflects strong interactions between polyanions and polycations in the multilayer

Structure of reaction products of benzylidenemalononitrile with tri(dimethylamino)phosphine, trimethyl phosphite and dimethylphos phorousacid

1. The reaction of tri(dimethylamino)phosphine with benzylidenemalononitrile gives a 1:1 adduct of bipolar structure with a P-C bond; some of the chemical properties of this adduct were studied. 2. Both trimethyl phosphite and dimethylphosphorous acid add to benzylidenemalononitrile at the C=C double bond. 3. The structure of the obtained products was confirmed by the IR and NMR spectra. © 1972 Consultants Bureau

Spatial structure of phosphorus-containing heterocycles - Communication 7. Synthesis and spatial isomerism in series of 2-methoxy-4-methyl-1,3-dioxa-2-phosphorinane derivatives

1. The geometric isomers of the corresponding tetra-coordinated phosphorus derivatives were obtained from the stereoisomeric cis- and trans-2-methoxy-4-methyl-1,3-dioxa-2-phosphorinanes by reaction with methyl iodide, the addition of sulfur, and oxidation. It was shown that the indicated reactions are stereospecific. 2. Conclusions regarding the spatial structure of the obtained compounds were made on the basis of determining the dipole moments, Kerr constants, and the IR and Raman spectra. © 1974 Consultants Bureau

Vibrational spectra of solutions of some derivatives of 1,3,2-dioxastibinane and their structure

1. The vibrational spectra of the 2-chloro and 2-alkoxy derivatives of 1,3,2-dioxastibinane in various phase states indicate they are capable of self-association through Sb-O...Sh and Sb-Cl...Sb bridges of various types, determined by the steric strain in the molecules. 2. In the crystalline phase polymers with strong and weak coordination bonds, dimers, and monomers are formed, depending on the type of substitution in the six-membered ring. In the series of the investigated compounds concentration-dependent signs of a polymer ⇄ dimer ⇄ monomer equilibrium are observed in the melts and the solutions. © 1986 Plenum Publishing Corporation

Preparation and vibrational spectra of various esters and chlorides of antimonous acid

1. 2-Methoxy-, 2-methoxy-4-methyl-, 2-methoxy-5,5-dimethyl-, 2-chloro-, 2-chloro-4-methyl-, and 2-chloro-5,5-dimethyl-1,3,2-dioxastibinanes have been prepared. 2. The bands due to the group vibrations ν (Sb-O) and ν (Sb-Cl) have been identified in the infrared and Raman spectra of the acyclic and cyclic esters and chlorides of antimonous acid obtained. © 1976 Plenum Publishing Corporation

Vibrational spectra and structure of antimony (III) trialkoxides

1. According to their vibrational spectra, antimony trialkoxides of formula Sb(OR)3 with R=CH3, C2H5, n-C3H7, and i-C4H9 are associated; no signs of association are observed for the compounds with R=i-C3H7 and t-C4H9. 2. The molecules of antimony tri-t-butoxide in the liquid state at 20°C exist in the form of rotational isomers having C1 (Cs) and C3 (C3v) symmetry, with the C1 (Cs) conformer predominating. Upon freezing, the C3 (C3v) conformer remains in the crystal. © 1981 Plenum Publishing Corporation

Production of some derivatives of 1,3,2-dioxastibinane and their vibrational spectra

1. 2-Chloro-, 2-methoxy-, and 2-tert-butoxy-4,6,6-trimethyl-1,3,2-dioxastibinanes and 2-tert-butoxy-5,5-dimethyl-and 2-tert-butoxy-4-methyl-1,3,2-dioxastibinanes were synthesized by the transetherification of chlorodiethoxy-, trimethoxy-, and tri-tert-butoxyantimony with the respective glycols. 2. According to the data on the vibration spectra, the 2-chloro and 2-alkoxy derivatives of 1,3,2-dioxastibinane are associated at the Sb-O bonds in the crystalline phase. The degree of association is determined by steric factors. 2-tert-Butoxy-4,6,6-trimethyl-1,3,2-dioxastibinane exists in the monomeric form. © 1985 Plenum Publishing Corporation

Optical echo in photonic crystals

The dynamics of photonic wavepacket in the effective oscillator potential is studied. The oscillator potential is constructed on a base of one dimensional photonic crystal with a period of unit cell adiabatically varied in space. The structure has a locally equidistant discrete spectrum. This leads to an echo effect, i.e. the periodical reconstruction of the packet shape. The effect can be observed in a nonlinear response of the system. Numerical estimations for porous-silicon based structures are presented for femtosecond Ti:Sapphire laser pump.Comment: 4 page

Synthesis and vibrational spectra of some 2-alkoxy-5,6-benzo-1,3,2-dioxastibepines

1) Tranesterification of the respective antimony trialkoxides with phthalyl alcohol have 2-methoxy-, 2-ethoxy-, and 2-tert-butoxy-5,6-benzo-1,3,2-dioxastibepines. 2) According to the IR and Raman spectra, 2-ethoxy- and 2-tert-butoxy-5,6-benzo-1,3,2-dioxastibepines are polymerized in the crystalline phase; the νSb-O frequencies are at least 100 cm-1 higher in melt and in solution than in the crystalline phase; they exist both as dimer and monomer. 2-tert-butoxy-5,6-benzo-1,3,2-dioxastibepine exists predominantly in the chair conformation. © 1987 Plenum Publishing Corporation

HYGIENIC VALUE OF VITAMIN D DEFICIENCY IN IRKUTSK REGION AND WAYS OF ITS PREVENTION

The status of vitamin D in the population of Irkutsk region has been determined by the contents of 25(OH)D3 in blood serum of268 people of different age. The highest rates were found in children - 37,78 ± 1,74 ng/ml. In men the level of activity of 25(OH)D3 was equal to 24,64 ± 2,33 ng/ml, in women up to 70years - 21,22 ± 0,85, older than 70 years -15,13 ± 2,24 ng/ml. The lowest rates are found in children with celiac disease -13,43 ± 2,14. More than 60 % of the population suffer from vitamin D deficiency. Yet wide-scale preventive measures are not possible due to limited range offortified food in the trade network