Effect of the alloying component MnO<Subscript>2</Subscript> on the type of V<Subscript>2</Subscript>O<Subscript>5</Subscript> electrocrystallization

The methods of polarization curves E-log I _a and atomic-force microscopy were used to study the mechanisms by which the alloying component MnO₂ affects the electrocrystallization of V₂O₅ in electrolysis from mixed solutions of salts of these metals.     

Electrolytic iron sulfides for thin-layer lithium-ion batteries

Thin-layer electrolytic iron sulfides synthesized on stainless steel substrates were studied in prototype lithium and lithium-ion batteries with an electrolyte composed of ethylene carbonate, dimethyl carbonate, and 1 M LiClO₄. A two-volt lithium-ion system with electrolytic iron sulfide and LiCoO₂ as negative and positive electrodes, respectively, was suggested. The discharge capacity of the prototype system is 350–400 mA h g⁻¹ Fe sulfide.     

Electrolytic nickel sulfide in a model electrochemical capacitor

Operation of an electrode made of electrolytic nickel sulfide in a prototype electrochemical capacitor with potassium hydroxide solutions of various concentrations was studied by cyclic voltammetry.     

Influence of substituted 1,4-anthraquinones on the chlorophyll fluorescence and photochemical activity of pea thylakoid membranes

The effect of substituted 1,4-anthraquinones on the photochemical activity and chlorophyll fluorescence of thylakoid membranes was examined. Both the fluorescence and the photochemical activity depend on the 1,4-anthraquinone substituent. Stronger quinone-induced quenching of the chlorophyll fluorescence than quinone-induced changes in the activity of photosystem II is observed. The type (Cl or Br) and the position (Cl) of the chalogen atom strongly influence the degree of inhibition of PSII electron transport and the quenching of chlorophyll fluorescence. The data suggest that the quenching of chlorophyll fluorescence is due rather to the interaction of the 1,4-anthraquinones and chlorophyll molecules than to an indirect effect caused by stimulation of the photochemistry.     

Electrolytic molybdenum oxides in lithium batteries

Nonstoichiometric molybdenum oxides (e-Mo_xO_y) were synthesized by cathodic reduction of aqueous ammonium and sodium molybdate solutions. Surface morphology of electrolytic (e) deposits, the chemical composition, crystal lattice structure, and the characteristics of electrochemical Li⁺ intercalation for such synthesized oxides were determined by the cation composition of molybdate solution and the conditions of deposit annealing. The electrochemical intercalation of Li⁺ ions in these Mo-oxides was investigated in thin-layer ballast-free electrodes, as a pasted mposite cathode in lithium batteries, and as an anode in lithium-ion batteries, with liquid organic and polymer electrolytes. The reversible discharge capacity of e-Mo₄O₁₁ synthesized from ammonium molybdate electrolyte in thin-layer ballast-free electrodes can exceed 225 mAh g^–1 for more than 170 cycles.     

New competitive enzyme-linked immunosorbent assay for determination of metallothionein in tissue and sera

A method for the determination of non-ionic surfactants (NS) in the presence of an excess of hydrocarbons is developed. The modified BiAS procedure combined with the indirect tensammetric method (BiAS-ITM) is applied for this purpose. The method consists of extraction of NS into ethyl acetate, precipitation of ethoxylates with modified Dragendorff reagent, removal of adsorbed hydrocarbons by washing with isooctane and the determination of NS in the dissolved precipitate by the ITM. The method is characterised by 96-100% recovery and RSD of 0.02-0.04 at a 1000-fold excess of hydrocarbons. The detection limit of the procedure is 1.5 mug and the linear dynamic range is 2-20 mug in the sample, which facilitates work within the range of 2-1000 mug through the use of aliquots. The non-modified version of the BiAS-ITM exhibits a loss of NS due to their extraction by droplets of residual hydrocarbons trapped in the precipitate. Isooctane as a washing agent is found to be the best among eight tested media: methanol, ethyl acetate, diisopropyl ether, chloroform, water, glacial acetic acid, benzene and isooctane.     

Electrolytic Deposition of Molybdenum Oxide from Aqueous Solutions at Room Temperature

The conditions of electrolytic deposition of molybdenum oxide from aqueous solutions at room temperature were studied and the optimal parameters of electrolysis, which provide deposits with necessary physical and structural characteristics, were chosen.     

Role of LHCII organization in the interaction of substituted 1,4-anthraquinones with thylakoid membranes

The chlorophyll fluorescence, photochemical activity and surface electric properties of thylakoid membranes with different stoichiometry of pigment-protein complexes and organization of the light-harvesting chlorophyll a/b protein complex of photosystem II (LHCII) were studied in the presence of substituted 1,4-anthraquinones. Data show strong dependence of the quenching of the chlorophyll fluorescence on the structural organization of LHCII. The increase of the LHCII oligomerization, which is associated with significant reduction of the transmembrane electric charge asymmetry and electric polarizability of the membrane, correlates with enhanced quenching effect of substituted 1,4-athraquinones. Crucial for the large quinone-induced changes in the membrane electric dipole moments is the structure of the quinone molecule. The strongest reduction in the values of the dipole moments is observed after interaction of thylakoids with 3-chloro-9-hydroxy-1,4-anthraquinone (TF33) which has the highest quenching efficiency. The quinone induced changes in the photochemical activity of photosystem II (PSII) correlate with the total amount of the supramolecular LHCII-PSII complex and depend on the number of substituents in the 1,4-anthraquinone molecule.     

Changes in the energy distribution between chlorophyll-protein complexes of thylakoid membranes from pea mutants with modified pigment content. I. Changes due to the modified pigment content

The low-temperature (77 K) emission and excitation chlorophyll fluorescence spectra in thylakoid membranes isolated from pea mutants were investigated. The mutants have modified pigment content, structural organization, different surface electric properties and functions [Dobrikova et al., Photosynth. Res. 65 (2000) 165]. The emission spectra of thylakoid membranes were decomposed into bands belonging to the main pigment protein complexes. By an integration of the areas under them, the changes in the energy distribution between the two photosystems as well as within each one of them were estimated. It was shown that the excitation energy flow to the light harvesting, core antenna and RC complexes of photosystem II increases with the total amount of pigments in the mutants, relative to the that to photosystem I complexes. A reduction of the fluorescence ratio between aggregated trimers of LHC II and its trimeric and monomeric forms with the increase of the pigment content (chlorophyll a, chlorophyll b, and lutein) was observed. This implies that the closer packing in the complexes with a higher extent of aggregation regulates the energy distribution to the PS II core antenna and reaction centers complexes. Based on the reduced energy flow to PS II, i.e., the relative increased energy flow to PS I, we hypothesize that aggregation of LHC II switches the energy flow toward LHC I. These results suggest an additive regulatory mechanism, which redistributes the excitation energy between the two photosystems and operates at non-excess light intensities but at reduced pigment content.