Study of hydrogen production and storage based on aluminum–water reaction

The rate and yield of hydrogen production from the reaction between activated aluminum and water has been investigated. The effect of different parameters such as water–aluminum ratio, water temperature and aluminum particle size and shape was studied experimentally. The aluminum activation method developed in-house involves 1%–2.5% of lithium-based activator which is diffused into the aluminum particles, enabling sustained reaction with tap water or sea water at room temperature. Hydrogen production rates in the range of 200–600 ml/min/g Al, at a yield of about 90%, depending on operating parameters, were demonstrated. The work further studied the application in proton exchange membrane (PEM) fuel cells in order to generate green electric energy, demonstrating theoretical specific electric energy storage that can exceed batteries by 10–20 folds.     

On the formation mechanism of metal nanoparticle nanotubes

We have previously described nanoparticle nanotubes (NPNTs), i.e., tubular metallic nanostructures comprising coalesced nanoparticles (NPs), obtained by passing citrate-stabilized metal (Au, Ag, Pd) NP solutions through aminosilane-modified nanoporous alumina membranes. Here we show that the mechanism of NPNT formation involves two stages: (i) electrostatic binding of a monolayer of metal NPs to the amine groups on the membrane pore walls; and (ii) accumulation of NP multilayers and room-temperature coalescence to form solid nanotubes. Free-standing NPNTs are obtained by post-dissolution of the membrane template. An improved fabrication apparatus enabled evaluation of the role of drying and other preparation parameters on the NP coalescence and NPNT formation and structure. Intermittent drying during the NP accumulation stage is necessary for the formation of solid NPNTs, while a slow flow rate of the colloid solution through the membrane pores and reversal of the flow direction promote the formation of more uniform and longer NPNTs.     

Microarray Analysis of Oligosaccharide‐Mediated Multivalent Carbohydrate–Protein Interactions and Their Heterogeneity

Carbohydrate–protein interactions (CPIs) are involved in a wide range of biological phenomena. Hence, the characterization and presentation of carbohydrate epitopes that closely mimic the natural environment is one of the long‐term goals of glycosciences. Inspired by the multivalency, heterogeneity and nature of carbohydrate ligand‐mediated interactions, we constructed a combinatorial library of mannose and galactose homo‐ and hetero‐glycodendrons to study CPIs. Microarray analysis of these glycodendrons with a wide range of biologically important plant and animal lectins revealed that oligosaccharide structures and heterogeneity interact with each other to alter binding preferences.     

Near-field optical photomask repair with a femtosecond laser

We present a high-resolution near-field optical tool designed for repair of opaque defects in binary photomasks. Both instrument design and near-field imaging and patterning results will be presented. Designed for ablative processing of thin metal films, the MR-100 incorporates an industrial amplified femtosecond laser, third harmonic generator and built-in autocorrelator. The ultrashort duration of the femtosecond pulses enables the tool to remove chrome layers with negligible damage to the surrounding metal or the underlying quartz substrate. The micropipette based near-field writing head can deliver power densities of hundreds of GW/cm² to spots of several hundred nanometres and below. Repairs on sample masks will be presented and the repair quality will be discussed.     

Calculation of the refractive index of lead-tin-telluride for infrared devices

The refractive indexNof lead-tin-telluride is calculated for frequencies near the fundamental absorption edge. The contribution toNfrom electron states near the band-edges is calculated more exactly than in previous works and a new expression for the contribution from the high frequency region is proposed. Good agreement is obtained between our calculations and experimental results. The change ofNdue to gain in injection laser is also calculated and it is shown that it cannot be neglected.     

Schema training in analogical reasoning.

In 3 experiments, college students learned how to solve 20 verbal analogy problems and took transfer and memory tests. Ss learned from worked-out examples that emphasized relational terms such as "part-to-whole" or under 3 other instructional conditions that required responding to examples or that excluded mention of relational terms. The former Ss were more accurate and faster then other Ss on solving new problems involving the same relations but less accurate in recognizing words from previous problems. This pattern is inconsistent with active responding theory, which predicts students learn best by generating answers and receiving feedback to problems, and is consistent with active learning theory, which predicts that students learn best by inducing schemas for particular problem types. Results indicate that schema induction is maximized when the schemas are made salient and the cognitive system is not overloaded. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Expression of GTP-dependent and GTP-independent tissue-type transglutaminase in cytokine-treated rat brain astrocytes

Tissue-type transglutaminases (TGases) were recently shown to exert dual enzymatic activities; they catalyze the posttranslational modification of proteins by transamidation, and they also act as guanosine triphosphatase (GTPase). Here we show that a tissue-type TGase is expressed in rat brain astrocytes in vitro, and is induced by the inflammation-associated cytokines interleukin-1beta and to a lesser extent by tumor necrosis factor-alpha. Induction is accompanied by overexpression and appearance of an additional shorter clone, which does not contain the long 3'-untranslated region and encodes for a novel TGase enzyme whose C terminus lacks a site that affects the enzyme's interaction with guanosine triphosphate (GTP). Expression of two clones revealed that the long form is inhibited noncompetitively by GTP, but the short form significantly less so. The different affinities for GTP may account for the difference in physiological function between these two enzymes.     

Transannular Aldol Condensation of Cis,Cis-Cyclodeca-3,8-Dien-1,6-Dione

NMR measurements with Eu(DPM)₃, as pseudocontact shift reagent, are able to differentiate between the two very unstable cis- and trans-ketols, obtained by transannular aldol condensations of cis, cis-cyclodeca-3,8-dien-1,6-dione. Azulenic compounds are the end products of the condensation.