Roughened surfaces of light-emitting diodes (LEDs) provide substantial improvement in light extraction efficiency. By using the laser-lift-off technique followed by an anisotropic etching process to roughen the surface, an n-side-up GaN-based LED with a hexagonal “conelike” surface has been fabricated. The enhancement of the LED output power depends on the surface conditions. The output power of an optimally roughened surface LED shows a twofold to threefold increase compared to that of an LED before surface roughening.

A molecular water oxidation catalyst (2) has been synthesized and immobilized together with a molecular photosensitizer (1) on nanostructured TiO2 particles on FTO conducting glass, forming a photoactive anode (TiO2(1+2)). By using the TiO2(1+2) as working electrode in a three-electrode photoelectrochemical cell (PEC), visible light driven water splitting has been successfully demonstrated in a phosphate buffer solution (pH 6.8), with oxygen and hydrogen bubbles evolved respectively from the working electrode and counter electrode. By applying 0.2 V external bias vs NHE, a high photocurrent density of more than 1.7 mA·cm(-2) has been achieved. This value is higher than any PEC devices with molecular components reported in literature.

Biological systems possess inherent molecular recognition and self-assembly capabilities and are attractive templates for constructing complex material structures with molecular precision. Here we report the assembly of various nanoachitectures including nanoparticle arrays, hetero-nanoparticle architectures, and nanowires utilizing highly engineered M13 bacteriophage as templates. The genome of M13 phage can be rationally engineered to produce viral particles with distinct substrate-specific peptides expressed on the filamentous capsid and the ends, providing a generic template for programmable assembly of complex nanostructures. Phage clones with gold-binding motifs on the capsid and streptavidin-binding motifs at one end are created and used to assemble Au and CdSe nanocrytals into ordered one-dimensional arrays and more complex geometries. Initial studies show such nanoparticle arrays can further function as templates to nucleate highly conductive nanowires that are important for addressing/interconnecting individual nanostructures.

The mechanism of hydrosilylation using the highly active precatalyst Karstedt's precatalyst (Pt x -(M vinyl M vinyl ) y , M vinyl M vinyl ) divinyltetramethyldisiloxane) was investigated using extended X-ray absorption fine structure (EXAFS), small-angle X-ray scattering (SAXS), and ultraviolet-visible (UV-vis) spectroscopy. Contrary to previous reports suggesting colloidal catalysts, we find that regardless of the stoichiometric ratio of hydrosilane to olefin, the catalyst is a monomeric platinum compound with silicon and carbon in the first coordination sphere. The platinum end product, however, is a function of the stoichiometry of the reactants. At excess olefin concentration, the platinum end product contains only platinum-carbon bonds, whereas at high hydrosilane concentration, the platinum end product is multinuclear and also contains platinum-silicon bonds. The two end products can interconvert by adding additional aliquots of the stoichiometrically deficient reagent. An explanation of the "oxygen" effect is also given. In the absence of oxygen, hydrosilylation of certain olefins does not occur. Oxygen serves to disrupt multinuclear platinum species that are formed when poorly stabilizing olefins are employed. Finally, we discuss the olefin isomerization reaction that may accompany hydrosilylation of terminal olefins. When the hydrosilylation reaction proceeds slowly due to poorly reactive olefins, the olefin isomerization products become significant. EXAFS analysis of solutions after olefin isomerization has occurred shows the presence of platinum-platinum bonded compounds.

The Cd 2؉ -inducible metallothionein (MTT1) gene was cloned from Tetrahymena thermophila. Northern blot analysis showed that MTT1 mRNA is not detectable in the absence of Cd 2؉ , is induced within 10 min of its addition, is expressed in proportion to its concentration, and rapidly disappears upon its withdrawal. Similarly, when the neo1 gene coding region flanked by the MTT1 gene noncoding sequences was used to disrupt the MTT1 locus, no transformants were observed in the absence of Cd 2؉ , and the number of transformants was proportional to increased Cd 2؉ concentration. The neo3 cassette, in which the MTT1 promoter replaced the histone gene HHF1 promoter of the previously used neo2 cassette, transformed cells at much higher frequencies than neo2 and produced germ-line knockouts where neo2 had failed. Rescuing the progeny of a mating of ␥-tubulin gene, GTU1, knockout heterokaryons with a GTU1 gene inserted into the MTT1 locus yielded >75 times more transformants than rescuing with the wild-type GTU1 gene itself. When cells rescued with the MTT1-GTU1 chimeric gene were transferred to medium lacking Cd 2؉ , they stopped growing and had phenotypic changes indistinguishable from cells containing only disrupted GTU1 genes. Thus, it is now possible to create conditional lethal mutants and study the terminal phenotypes of null mutations for essential genes by replacing the endogenous gene with one under the control of the MTT1 promoter. The MTT1 promoter also resulted in Ϸ30 times more overexpression of the IAG48[G1] surface antigen gene of the ciliate fish parasite Ichthyophthirius multifiliis than the highly expressed BTU1 promoter, accounting for Ϸ1% of the total cell protein. Thus, the MTT1 promoter should enable routine over-expression of endogenous and foreign genes in Tetrahymena.

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A manganese(III) corrole complex, 1, has been synthesized and used to study a potential mechanism for oxidation of water to molecular oxygen. Oxidation by t-BuOOH gave the Mn(V)=O complex 2. Addition of hydroxide led to release of oxygen via the Mn(IV) complex 4 and regeneration of complex 1. It could be shown that the oxygen from (18)O-labeled water was incorporated in both the formed molecular oxygen and the peroxy intermediate 4.

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