On quadratic and sesquilinear functionals

LetX be a leftA-module, whereA is either a complex Banach *-algebra with an identity element or the field of quaternions. The main result of this note is that forQ, anA-quadratic functional defined onX, there exists a sesquilinear functionalB such thatB(x,x)=Q(x) holds for allxX.     

A new convenient synthesis of N-acyl-2-(dimethoxyphosphoryl)glycinates

Easily accessible N-acyl-2-triphenylphosphonioglycinate tetrafluoroborates react smoothly with trimethylphosphite in the presence of methyltriphenylphosphonium iodide to give N-acyl-2-(dimethoxyphosphoryl)glycinates in good or very good yields. The dimethoxyphosphorylglycinates may be isolated by column chromatography, or used directly for the Wadsworth-Emmons synthesis of α,β-dehydro-α-amino acids in a one-pot procedure without purification.     

Infrared spectroscopic study of the structure of the tetrabutyl S-dithiopyrophosphate complex of silver

The structure of the complex Ag·TBDTPP (tetrabutyl S-dithiopyrophosphate) formed in HNO₃ medium was studied by IR and NMR methods. The complex is involved in the isomerization of TBDTPP in the presence of Ag⁺ and NO ₃ ⁻ ions. In the IR spectra, we observe the disappearance of P−O−P band and the occurrence of new absorption bands associated with P−S−P and P=O bonds. The silver ion is coordinated to the thiophosphoryl group of the isomer molecule. The influence of HNO₃ concentration on complex formation is discussed.     

Size exclusion chromatographic characterization of sodium hyaluronate fractions prepared by high energetic sonication

Summary A high molecular weight sodium hyaluronate isolated from rooster combs was degraded by ultrasonication. High-performance size exclusion chromatography allowed rapid and accurate determination of molecular weight parameters (M_z, M_w, M_n) and distributions. The time dependence of hyaluronan ultrasonication to the molecular characteristics of the polymer was investigated. A non-random nature of the degradation process was demonstrated and the reciprocal M_n value was found to be linearly proportional to the time of ultrasonication.     

Oxygen equilibrium pressure above V2O5−x and thermodynamic properties of this oxide system

Measurements of oxygen equilibrium pressure above the V₂O_5?x oxide system have been performed within the temperature range 575 to 615°C. The results have been used to determine the standard enthalpy and entropy in the reaction V₆O₁₃ + O₂ = 3 V₂O₅. The thermodynamic properties of the V₂O_5?x system (at x < 1) cited in the literature have been discussed for all the equilibria postulated.     

Parabolic focal conics in self-assembled solid films of cellulose nanocrystals

Suspensions of cellulose nanocrystals form colloidal chiral nematic phases. The liquid crystalline order in these suspensions can be captured in solid films by slow evaporation of the liquid. Studies of the microstructure of such chiral nematic solid films revealed parabolic focal conic (PFC) defects, a symmetric form of focal conic defects in which the line defects form a pair of perpendicular, antiparallel, and confocal parabolas. The cellulose films with PFC defects were characterized by polarized-light and atomic force microscopy. The film surface showed a regular array of large and small elevations resulting from the displacement of the structural layers. Film fracture lines showed a series of layered half-cones. The microstructure of the films was modeled by computer. The model revealed that many structural layers terminate at the film surface.     

Thermal decomposition of mineral zircon by alkali metal hydroxides

Thermal decomposition of zircon mineral was studied in the presence of sodium and potassium hydroxides and in the presence of a waste mixture of hydroxides containing NaOH and KOH in a weight ratio of 23. The process was controlled in such a way that the decomposition products might contain the minimum possible amount of alkali and could thus be applied for the syntheses of zircon pigments without any further exacting treatment.

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Zusammenfassung Es wurde die thermische Zersetzung eines Zirkonminerals in Gegenwart von Natrium- und Kaliumhydroxid-sowie in Gegenwart einer Altlauge mit einem Gehalt an NaOH und KOH im Verhältnis zwei zu drei untersucht. Der Prozeß wird derart gesteuert, daß die Zersetzungsprodukte einen möglichst geringen Anteil an Lauge besitzen und so ohne weitere arbeitsaufwändige Behandlungen zur Synthese von Zirkonpigmenten verwendet werden können.

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Sulfide ion electrooxidation catalysed by cobalt phthalocyanine microcrystals

Electrooxidation of sulfide ion catalysed by microcrystals of cobalt phthalocyanine was investigated by cyclic voltammetry in 0.5M KNO₃ at pH 9.22. Traces of catalyst were immobilized at the surface of a paraffin-impregnated graphite electrode by the mechanical transfer of its powder. The electro-oxidation of HS^– proceeds in two irreversible steps, with the first peak between 0 V and –0.12 V and the second at 0.17 V. The first step is second order in HS^– and its product is the adsorbed disulfide, which may further dissociate to give adsorbed sulfur atoms. The reduction of sulfur occurs at –0.1 V.     

Photocatalytic TiO2 Coatings: Effect of Substrate and Template

Summary. Transparent TiO₂ films with a high photodegradation activity towards an azo dye in aqueous solution were prepared by sol–gel processing. Films on soda–lime glass supports protected with a thin silica barrier layer exhibited better crystallization and monodisperse nanoparticles, higher absorption of light below 370 nm, and higher photocatalytic activity than those films deposited on bare glass supports proving the detrimental effect of interdiffused sodium ions on the development of the anatase nanostructure. The effect of substrate was more pronounced in thinner films (300 nm) than in thicker ones (1200 nm), which were achieved by adding a template (i.e. Pluronic F127) to the sol.     

Correlation between Lipophilicity of the Ligands and the Hepatobiliary Properties of the Radiopharmaceuticals: Approach to the Development of New IDA Derivatives

The partition coefficient (log P) for n-octanol/water system was calculated applying PACO program for various theoretically possible mono and dihalogenated IDA derivatives. Some of the synthesized ligands (SOLCOIODIDA, IODIDA and DIIODIDA) were labeled with the technetium-99m. The biodistribution and influence of bilirubin on their biokinetics were investigated in rats. The correlation between partition coefficients of ligands increase (log P) and better hepatobiliary properties of ^99mTc-IDA derivatives was determined. The values of log P increase from 1.16 for SOLCOIODIDA, 3.11 for IODIDA to 3.47 for DIIODIDA. In correlation with these results, biliary excretion decreased for 59% for ^99mTc-SOLCOIODIDA and 11% for ^99mTc-IODIDA and ^99mTc-DIIODIDA under hyperbilirubinemia (3.5 min after injection) and 45%, 11% and 0.38% respectively (15 min after injection). The highest biliary excretion had ^99mTc-DIIODIDA (55.4% for 3.5 min). Considering the correlation between hepatobiliary properties and log P, the evaluation of biological properties for various trifluoromethyl mono and dihalogenated IDA derivatives was performed on the basis of the calculated log P in order to synthetize a new radiopharmaceutical for hepatobiliary scintigraphy.