Shape and color of au nanoparticles follow biocatalytic processes

The NAD(P)H-mediated growth of Au nanoparticles (NPs) in the presence of ascorbic acid, AuCl4-, and cetyltrimethylammonium bromide leads to the formation of shaped NP structures consisting of dipods, tripods, and tetrapods. The shaped particles exhibit a red-shifted plasmon absorbance at lambda = 680 nm, consistent with the existence of a longitudinal plasmon exciton. High-resolution transmission electron microscopy analysis of the tripod and tetrapod structures reveals directional growth along the <211> and <010> directions, respectively. The shaped Au NPs could be generated by a biocatalytic process using alcohol dehydrogenase, NAD+, and ethanol, and the resulting blue color provides a colorimetric test for ethanol.     

Structure, stability, and quantum conductivity of small diameter silicon nanowires

Structures and energetics of various types of silicon nanowires have been investigated using both quantum and classical molecular dynamics simulations to determine the most stable forms. The tetrahedral type nanowires have been found to be the most stable and, surprisingly, the polycrystalline forms of nanowires, while having the smallest surface to bulk ratio, are found to be the least stable. We also show that the cagelike nanowires have greater thermal stability than the tetrahedral nanowires. Furthermore, their electrical conducting properties are found to be better than those of tetrahedral nanowires, suggesting useful molecular electronic applications.     

Examples of amalgamated products

The rank of a groupG is the minimal number of elements that generateG. For any natural numbern we construct two groups,G ₁ of rankr(G ₁)=n andG ₂ of rankr(G ₂)=2n such that their amalgamated product over an infinite cyclic subgroup, malnormal in both factors, is generated by 2n=r(G ₁)+r(G ₂)−n elements. We also consider an example of an amalgamated product ofn factors: such thatr(G)=n +1, andr(A)≥1. This example realizes the lower bound given by Weidmann [W1] (see Theorem 2 in the present paper).     

Synthesis of N-acetyllactosamine based branched hexasaccharide

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Higher-order asymptotic solutions in fluids of various configurations

Applying perturbation methods, symbolic computation, and generalizing the solution method, higher-order asymptotic solutions are constructed in Lagrangian variables for several models describing 2D standing wave motions in fluids of various configurations. Three main parameters of the fluid configuration, depth, capillarity, and stratification layer, are considered. The frequency-amplitude dependences are obtained and compared with those known in the literature in Eulerian and Lagrangian variables. The comparison shows that the analytical frequency-amplitude dependences are in complete agreement with previous results known in the literature and with the results obtained for other models. A generalization allows us to investigate critical phenomena for standing waves in fluids of various configurations. Namely, special attention is focused on critical values of one parameter, the fluid depth. The frequency-amplitude dependences are analyzed from the point of view of critical values: critical points and critical curves are determined for several models describing standing waves in fluids of various configurations.     

Investigation of radioactive lead,uranium, and thorium in environmental waters by extraction chromatography resins

A time-saving and sensitive method for monitoring low concentration (activities) of ²¹⁰Pb, ²³²Th, and ²³⁰Th and ²³⁸U, ²³⁴U, and ²³⁵U in water samples has been developed. Through the combination of co-precipitation and extraction chromatography by 3M RAD disks and UTEVA (Eichrom) columns effective radiochemical separation of the analytes was carried out. Thorium and uranium activities were determined by alpha spectrometry and lead activity by LSC, respectively. The minimal detectable activities obtained were 0.6?Bq?m^?3 for uranium, 0.29?Bq?m^?3 for thorium, and 2.5?Bq?m^?3 for ²¹⁰Pb. More than 150 different waters were analysed for uranium content and only 30 for lead and thorium. The investigations are still in progress.