Influence of noncontractile motion of plasmalemma upon cotton fiber cell wall structure

Unusual noncontractile motion in vivo within the fibers growing on cotton ovules was found for four cotton genotypes. Structural investigations have shown that, in addition to the active motion related to fiber cell growth, a simultaneous spiral rotation of the cytoplasmic membrane occurs. Due to translational growth of the fiber cell apices and spiral rotation of plasmalemma, the fibers of cotton cultivars take on a twisted, corkscrew-like external shape. Optical microphotos illustrate the formation process of the fiber cell wall at different stages of growth and noncontractile motion in cotton fiber cells.     

Cohomology of Subregular Tilting Modules for Small Quantum Groups

Let U be a quantumgroup with divid d powers at root ofunity constructed froma rootsystem R .Let u U b th small quantumgroup.Th cohomologyof u with trivial coefficients was computed by Ginzburg and Kumar.It turns out to be isomorphic to the functions algebra of the nilpotent cone of a semisimpl algebraic group with root system R .In this not we calculate cohomology of u with coefficients in simplest reducible tilting modul with nontrivial cohomology.It appears to b isomorphic to th functions algebra of th closure of the subregular nilpotent orbit.     

Research on orotron oscillator with dispersive open resonant system

Theoretical and experimental results of an investigation into a new resonant system have been obtained. This system is named the sphere-corner-echelette open resonator (SCEOR) due to the employment of a mirror that was formed by two echelettes at the angles of 45° to the resonator axis. It turns ont that this resonator is excited on the specific modes not unique to others oscillating systems. There are presented the results of the experimental research of the orotron oscillator with the SCEOR. The spectrum of this device contains only the fundamental modes such as theT E M ₀₀₆,T E M ₀₀₇,T E M ₀₀₈. The efficiency of the orotron is improved, when all other factors are the same the orotron with a much used sphere-cylindrical open resonator.     

Synthesis of tungsten carbide nanopowder via submerged discharge method

Tungsten carbide nanopowder was prepared via pulsed discharge of bulk tungsten and graphite rods immersed in pure ethanol. The effect of discharge parameters on the characteristics of final products was investigated. Structural and morphological characterization of nanopowder was performed by means of X-ray diffraction analysis and transmission electron microscopy. In order to determine the feasibility of using synthesized material as an electrocatalyst, tungsten carbide nanopowder was tested for hydrogen evolution. A correlation was found between morphology of nanoparticles, their phase composition and electrocatalytic activity.     

A mass spectrometric study of halogenated beryllium μ4-oxohexa-μ-acetates

The electron impact mass spectra of Be₄O(CHal₃CO₂)₆ (Hal = F, Cl) are reported. The compounds give two series of fragment ions, [Be₄OL_x]⁺ and [Be₄OL₊]⁺, where L is an intact ligand or its fragmentation product. The major ligand dissociation path is the elimination of CHal₂CO₂ with halogen transfer to the metal. Other processes of importance are the loss of acid anhydride fragments, CF₂ with fluorine shift to the carboxyl group carbon atom, and halogens. Trinuclear ions also undergo decarboxylation, e.g. to give [Be₂O(CHal₃CO₂)₂(CHal₃)]⁺. Both spectra contain comparatively intense peaks of double-charged ions. The fragmentation patterns are rationalized by stereochemical considerations.     

Fragmentation of ligands and stability of inorganic skeletons in the mass spectra of polynuclear beryllium and zinc complexes

Electron impact induced fragmentations of 12 beryllium and zinc μ₄-oxohexa-μ-acido and μ₄-oxopenta-μ-acido-μ-alkoxo complexes containing carboxylato, fluoro- and chloroacetato, alkoxo and nitrato groups as ligands are discussed. The spectra are interpreted in terms of a model of weakly interacting fragments. It is demonstrated that in the systems under consideration, structural rather than electronic factors play the determining role in the stabilization of fragment ions. All the spectra are dominated by terra- and trinuclear complex cations containing OM₄ and OM₃ (M = Be, Zn) units, respectively. Their relative abundances correlate with the number of ligand vibrational degrees of freedom, being independent of ligand electronic characteristics.     

The determination of nano-amounts of iodine in waters,plants, foods,special diets,tissues, and soils

Summary A universal method for the determination of nano-amounts (ng= =10^–9 g) of iodine in various types of biological material is described. The recovery of added iodine standard averaged around 95%. The standard deviation for the method is ± 5%.

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Zusammenfassung Eine universelle Methode zur Bestimmung von Nanogramm-Mengen Jod in verschiedenen biologischen Materialien wird beschrieben. Zugesetzte Jodmengen wurden durchschnittlich zu 95% wiedergefunden. Die Standard-abweichung der Methode beträgt ±5%.

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Résumé On décrit une méthode universelle pour le dosage de quantités de l'ordre du nanogramme (1 ng=10^–9 g) d'iode dans les différents types de substance biologique. La concordance avec l'iode étalon ajouté atteint en moyenne 95% environ. La déviation standard de la méthode est de ±5%.

     

NMR-spectroscopic studies on solvent electrophilic properties,Part II: Binary aqueous-non aqueous solvent systems

Acceptor numbers have been determined for binary mixtures of water with acetonitrile (AN), dioxane, acetone (AC), pyridine (PY), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), hexamethylphosphoramide (HMPA), methanol, ethanol andi-propyl alcohol. The electrophilic properties of binary aqueous-non aqueous solvent mixtures are determined both by selective solvation and specific solvent-solvent interactions. The variation of the acceptor number as a function of solvent composition is interpreted in terms of the previously determined nucleophilic and electrophilic properties of the pure components and their specific solvent structure.With 6 FiguresIn eq. (1), ^corr means the³¹P chemical shift ofEt ₃PO at concentration zero in a solventS referred to an infinitely dilute solution ofEt ₃PO inn-hexane and corrected for differences in volume susceptibilities betweenS and hexane, ^corr (Et ₃PO·SbCl₅) denotes the corresponding chemical shift value for the adductEt ₃PO·SbCl₅ at infinite dilution in 1,2-dichloroethane which is arbitrarily assigned anAN=100.