Interaction of dipicolinatodioxovanadium(V) with polyatomic cations and surfaces in reverse micelles

In confined media such as reverse micelles, molecular probes frequently reside at and interact strongly with the interface. If the interface is charged, it is often difficult to separate effects arising from interactions with the charged species from the effect of the interfacial environment. With reverse micelles as a model system, the work reported here explores the interaction of the charged surfactant headgroups at a self-assembled interface with the dipicolinatodioxovanadium(V) coordination complex. The vanadium complex studied in these experiments serves as an excellent probe to investigate how charged metal complexes interact with lipid interfaces. For comparison, measurements were also carried out probing the interaction of the vanadium complex with a model cationic headgroup, tetramethylammonium bromide. The impact of the environment is gauged by changes in the 51V chemical shift, longitudinal relaxation times, and 1H NMR pulsed field gradient measurements. These measurements suggest that while interface component parts, as modeled by the dispersed systems, interact with the vanadium complex, the interfacial environment perturbs the complex substantially more strongly than the sum of the components alone. Coulomb attraction dominates the interaction in all systems probed and surprisingly orients the hydrophobic portion into the bulk water.     

Industrial scale-up of pH-controlled liquid hot water pretreatment of corn fiber for fuel ethanol production

The pretreatment of cellulose in corn fiber by liquid hot water at 160°C and a pH above 4.0 dissolved 50% of the fiber in 20 min. The pretreatment also enabled the subsequent complete enzymatic hydrolysis of the remaining polysaccharides to monosaccharides. The carbohydrates dissolved by the pretreatment were 80% soluble oligosaccharides and 20% monosaccharides with o1% of the carbohydrates lost to degradation products. Only a minimal amount of protein was dissolved, thus enriching the protein content of the un dissolved material. Replication of laboratory results in an industrial trial at 43 gallons per minute (163 L/min) of fiber slurry with a residence time of 20 min illustrates the utility and practicality of this approach for pretreating corn fiber. The added costs owing to pretreatment, fiber, and hydrolysis are equivalent to less than $0.84/gal of ethanol produced from the fiber. Minimizing monosaccharide formation during pretreatment minimized the formation of degradation products; hence, the resulting sugars were readily fermentable to ethanol by the recombinant hexose and by pentose-fermenting Saccharomyces cerevisiae 424A (LNH-ST) and ethanologenic Escherichia coli at yields >90% of theoretical based on the starting fiber. this cooperative effort and first successful trial opens the door for examining the robustness of the pretreatment system under extended run conditions as well as pretreatment of other cellulose-containing materials using water at controlled pH.     

10(-10) temporal contrast for femtosecond ultraintense lasers by cross-polarized wave generation

We take advantage of nonlinear properties associated with chi(3) tensor elements in BaF2 cubic crystal to improve the temporal contrast of femtosecond laser pulses. The technique presented is based on cross-polarized wave (XPW) generation. We have obtained a transmission efficiency of 10% and 10(-10) contrast with an input pulse in the millijoule range. This filter does not affect the spectral shape or the phase of the cleaned pulse. It also acts as an efficient spatial filter. In this method the contrast enhancement is limited only by the extinction ratio of the polarization discrimination device.     

The preparation and some reactions of 1,3,2-thiazaphospholidine-2-ones

1,3,2-Thiazaphospholidine-2-ones have been prepared by rearrangement of the corresponding 1,3,2-oxazaphospholidine-2-thiones. The stereochemical course of ring opening reactions has been investigated.     

Cyclopolymerisation. 8. Mitt. Die Synthese von Allylamino-Monomeren durch die Mannich-Reaktion und deren Polymerisation

Ohne Zusammenfassung     

A variational approach to superfluidity

A variational approach to problems in quantum statistical mechanics is described and it is shown how to determine the best quasi-free approximation to the equilibrium state. The relation between this approximation and the Bogoliubov approximation in superfluidity is discussed.     

UV-INDUCED ELEVATION OF SKIN GLYCOSAMINOGLYCAN LEVELS I: RAPID MEASUREMENT OF SKIN GLYCOSAMINOGLYCANS BY TITRATION WITH ACRIDINE ORANGE*

Abstract— We have developed a simple, rapid, sensitive procedure for measuring polyanionic glycosaminoglycans (GAG) in unfixed defatted lyophilizedSK–1 hairless mouse skin by means of quantitative measurement of uptake of the fluorescent dye acridine orange (AO), which was shown to be GAG-specific under the conditions of these experiments. This method is suitable for detecting and estimating elevations in steady skin GAG levels due to UV irradiation.     

Reactions of atomic nitrogen and atomic hydrogen with methylacetylene

The reaction of nitrogen atoms with methylacetylene has been studied using a fast-flow low-pressure reactor coupled to a mass spctrometer by a nozzle-beam sampling system. Hydrogen atom concentrations were measured by ESR analysis. Experimental second-order rate constants for the consumption of N atoms, of C₃H₄, and for the formation of N₂ were determined in the temperature range of 283° to 485°K. Product profiles of all stable species and of hydrogen atoms and methyl radicals were obtained for different initial concentrations of the reactants. Two different reaction pathways can be distinguished: one provides for recombination of N atoms, and the second leads to the formation of cyano compounds and other hydrocarbons. Only the latter process is influenced by the addition of hydrogen atoms. Mechanisms for the two pathways are discussed.