Photo‐Electrochemical C−H Bond Activation of Cyclohexane Using a WO3 Photoanode and Visible Light

The photo‐electrochemical C?H bond activation of cyclohexane to produce cyclohexanol and cyclohexanone (KA oil) with high partial oxidation selectivity (99 %) and high current utilization ratio (76 %) was achieved in air at room temperature at atmospheric pressure. The production rate of KA oil was accelerated by applying a bias. The incident photon to current efficiencies at 365 and 420 nm were 57 % and 24 %, respectively.     

Zn-doped AlInAs grown at high temperature by metalorganic chemical vapor deposition

Zn-doped AlInAs growth at high temperature, mainly at 750°C, by metalorganic chemical vapor deposition is investigated. When introducing DEZn during AlInAs growth, it is necessary to increase the TMAl flow rate in order to make the layer lattice-matched to InP. This is due to the enhanced In incorporation rather than the large covalent radius of Zn. To clarify the electrical characteristics, the dependence of the DEZn flow rate, the V/III ratio, and the growth temperature are investigated using the van der Pauw Hall method. In our growth system, a GaInAs intermediate layer is effective in preventing n-type inversion in Zn-doped AlInAs, which occurs when it is grown directly on an InP buffer layer. In addition, a large DEZn flow rate is effective for reducing carrier compensation in Zn-doped AlInAs layers grown at 750°C. Si impurities are apparently the cause of the type-inversion and compensation in Zn-doped AlInAs.     

Lectin-based structural glycomics: a practical approach to complex glycans

Glycans exist in nature in various forms of glycoconjugates, i.e., glycoproteins, glycolipids, and glycosaminoglycans, either in soluble or membrane-bound forms. One of their prominent properties distinguished from nucleic acids and proteins is "heterogeneity" largely attributed to their inherent features of biosynthesis. In general, various methods based on the physicochemical principles have been taken for their separation and structural determination although all of them require prior liberation of glycans and appropriate labeling. On the other hand, a series of carbohydrate-binding proteins, or "lectins," have extensively been used in a more direct manner for cell typing, histochemical staining, and glycoprotein fractionation. Although most procedures conventionally used are useful, unfortunately they lack "throughput" comparable to a performance required for current omics studies. Recently, a novel technique called lectin microarray has attracted increasing attention from not only glycoscientists but also researchers in other fields, because it is straightforward and also informative. The method is innovating in that it enables direct approach to glycoconjugates such as glycoproteins and even cells without liberation of glycans from the core substrate, and therefore can be effectively applied for the sake of differential profiling in various fields. Concept, strategy, and technical advancement of lectin microarray are described. Also, as an introduction to glycomics, the authors explain the motivation to challenge this theme.     

Contribution of atmospheric nitrate to stream‐water nitrate in Japanese coniferous forests revealed by the oxygen isotope ratio of nitrate

Evaluation of the openness of the nitrogen (N) cycle in forest ecosystems is important in efforts to improve forest management because the N supply often limits primary production. The use of the oxygen isotope ratio (δ¹⁸O) of nitrate is a promising approach to determine how effectively atmospheric nitrate can be retained in a forest ecosystem. We investigated the δ¹⁸O of nitrate in stream water in order to estimate the contribution of atmospheric NO in stream‐water NO (f_atm) from 26 watersheds with different stand ages (1–87 years) in Japan. The stream‐water nitrate concentrations were high in young forests whereas, in contrast, old forests discharged low‐nitrate stream water. These results implied a low f_atm and a closed N cycle in older forests. However, the δ¹⁸O values of nitrate in stream water revealed that f_atm values were higher in older forests than in younger forests. These results indicated that even in old forests, where the discharged N loss was small, atmospheric nitrate was not retained effectively. The steep slopes of the studied watersheds (>40°) which hinder the capturing of atmospheric nitrate by plants and microbes might be responsible for the inefficient utilization of atmospheric nitrate. Moreover, the unprocessed fraction of atmospheric nitrate in the stream‐water nitrate in the forest (f_unprocessed) was high in the young forest (78%), although f_unprocessed was stable and low for other forests (5–13%). This high f_unprocessed of the young forest indicated that the young forest retained neither atmospheric NO nor soil NO effectively, engendering high stream‐water NO concentrations. Copyright © 2010 John Wiley & Sons, Ltd.     

Copolymerization of Metal Nanoparticles: A Route to Colloidal Plasmonic Copolymers

The resemblance between colloidal and molecular polymerization reactions is very useful in fundamental studies of polymerization reactions, as well as in the development of new nanoscale systems with desired properties. Future applications of colloidal polymers will require nanoparticle ensembles with a high degree of complexity that can be realized by hetero‐assembly of NPs with different dimensions, shapes, and compositions. A method has been developed to apply strategies from molecular copolymerization to the co‐assembly of gold nanorods with different dimensions into random and block copolymer structures (plasmonic copolymers). The approach was extended to the co‐assembly of random copolymers of gold and palladium nanorods. A kinetic model validated and further expanded the kinetic theories developed for molecular copolymerization reactions.     

Anisotropic Self‐Assembly of Citrate‐Coated Gold Nanoparticles on Fluidic Liposomes

The behavior of self‐assembly processes of nanoscale particles on plasma membranes can reveal mechanisms of important biofunctions and/or intractable diseases. Self‐assembly of citrate‐coated gold nanoparticles (cAuNPs) on liposomes was investigated. The adsorbed cAuNPs were initially fixed on the liposome surfaces and did not self‐assemble below the phospholipid phase transition temperature (T_m). In contrast, anisotropic cAuNP self‐assembly was observed upon heating of the composite above the T_m, where the phospholipids became fluid. The number of self‐assembled NPs is conveniently controlled by the initial mixing ratio of cAuNPs and liposomes. Gold nanoparticle protecting agents strongly affected the self‐assembly process on the fluidic membrane.     

Attaining 186-nm light generation in cooled beta-BaB(2)O(4) crystal

The transparency range of beta-BaB(2)O(4) (BBO) was expanded by means of cooling, and the resulting absorption coefficient at 193.4 nm was reduced to 0.29cm(-1) at 91 K from 1.39cm(-1) at 295 K. Further, generation of light at 186.0 nm (the measurement limit in air) by type I sum-frequency generation (SFG) based on fundamental (744-nm) and third-harmonic (248-nm) light from a Ti:sapphire laser was confirmed for cooled BBO. Calculations based on observed data for SFG wavelengths and phase-matching angles indicate a potential for cooled BBO to generate wavelengths as low as 181.7 nm.     

Profiling the Cell Surface Glycome of Five Fungi Using Lectin Microarray

Fungal surface glycans play roles in cell protection and interaction. Our knowledge of fungal glycans, however, is limited to model yeasts and a few medically/industrially important fungi. We evaluated the usefulness of a lectin microarray in analysis of live cell surface glycans and then applied the technique to glycome of varieties of yeast-form fungi from various phyla and subphyla. We found glycan profiles are different among and within taxonomic groups. For example, Saccharomycotina were classified into two groups, one bound to mannose-specific lectins and the other bound to galactose/N-acetylgalactosamine-specific lectins. In Basidiomycota, Pucciniomycotina yeasts were distinguished from other subphylum members in binding to fucose-specific lectins. Supplemental materials are available for this article. Go to the publisher's online edition of Journal of Carbohydrate Chemistry to view the free supplemental file.