Synergistic N‐Heterocyclic Carbene/Palladium‐Catalyzed Reactions of Aldehyde Acyl Anions with either Diarylmethyl or Allylic Carbonates

Benzylation and allylation of aldehyde acyl anions were enabled by the merger of a thiazolium N‐heterocyclic carbene (NHC) catalyst and a palladium/bisphosphine catalyst in a synergistic manner. Owing to the mildness of the reaction conditions, various functional groups were tolerated in the substrates.     

Preparation of Anti-Glycyrrhetinic Acid Monoclonal Antibody for Application in an Indirect Competitive Enzyme-Linked Immunosorbent Assay

Glycyrrhetinic acid is a major metabolite of glycyrrhizin, which is one of the main components of licorice roots and is considered to be one of the pharmacologically active substances in licorice. A new hybridoma cell line, named G-2A6, was generated by fusing mouse myeloma cells and splenocytes, which were immunized using glycyrrhetinic-acid–keyhole limpet hemocyanin to produce a monoclonal antibody (mAb) against glycyrrhetinic acid. Using the anti-glycyrrhetinic acid mAb, we attempted to develop a simple, rapid, and highly sensitive indirect competitive enzyme-linked immunosorbent assay (icELISA). The developed icELISA had a range from 3.91 to 125?ng/mL with low coefficients of variation (less than 5%) and demonstrated a high recovery rate of glycyrrhetinic acid spiked into licorice powder (average?=?101.76%). In addition, the icELISA could determine the glycyrrhetinic acid concentration in glycyrrhetinic-acid-spiked human serum with simple pretreatment, which suggests that the developed ELISA system using anti-glycyrrhetinic acid mAb would prove to be an effective and useful tool for determining glycyrrhetinic acid in various fields such as the analysis of Glycyrrhiza plants and pharmacokinetic studies of glycyrrhetinic acid during the administration of glycyrrhetinic acid, glycyrrhizin, and/or licorice-based medical agents.     

Optical characterization of laser-induced crystallized silicon films

Optical absorption coefficient spectra of thin silicon films were precisely investigated using a simple reflectance system with total reflectance mirrors placed on the rear side of samples in order to cancel an interference effect in a range between 1.1 eV and 3 eV. The absorption coefficient decreased according to crystallization as the laser energy increased and it got similar to that of single crystalline silicon in the range of 1.7 eV 3 eV. However, the absorption coefficient was higher than 10² cm^–1 in the photon energy lower than 1.3 eV. This probably results from band tail states caused by defect states localized at grain boundaries in the crystallized films. 2.5%-phosphorus doped laser crystallized silicon films had a high optical absorption coefficient ( > 10⁴ cm^–1) in the low photon energy range (1.1 eV 1.7 eV) caused by free carriers produced from the dopant atoms activated in the silicon films. The experimental results gave the carrier density of 1.3 × 10²¹ cm³ and the carrier mobility of 20 cm²/Vs.     

Determination of chromium(vi) in natural waters by the sorption of chromium-diphenylcarbazone with xad-2 resin

The sorption of the chromium(III)-diphenylcarbazone complex (Cr-DPC) with XAD-2 has been investigated, for use in the separation of Cr(VI) from Cr(III) species in natural waters. Cr-DPC is formed from the reaction of Cr(VI) with diphenylcarbazide, but Cr(III) species give no reaction in aqueous solution. The addition of sodium chloride or sodium beta-naphthalenesulphonate markedly enhances the sorption. The Cr-DPC sorbed on XAD-2 can be almost completely eluted with organic solvents, especially methanol, but about 5% of it is irreversibly sorbed and cannot be eluted. The excess of diphenylcarbazide and some of the organic matter in natural waters are also sorbed on XAD-2 but most of this can also be eluted with methanol. Organic matter which interferes with measurement of the absorbance of Cr-DPC can almost all be removed by extraction with chloroform. By use of these techniques, Cr(VI) in sea-water has been determined by the standard-addition method. Although about 50 litres of sea-water are necessary for the analysis, organic and colloidal Cr(III) species do not interfere.     

Structural change in a series of protonated layered perovskite compounds, HLnTiO4 (Ln=La, Nd and Y)

A deuterated n=1 Ruddlesden-Popper compound, DLnTiO₄ (HLnTiO₄, Ln=La, Nd and Y), was prepared by an ion-exchange reaction of Na⁺ ions in NaLnTiO₄ with D⁺ ions, and its structure was analyzed by Rietveld method using powder neutron diffraction data. The structure analyses showed that DLaTiO₄ and DNdTiO₄ crystallized in the space group P4/nmm with a=3.7232(1) and c=12.3088(1) Å, and a=3.7039(1) and c=12.0883(1) Å, respectively. On the other hand, DYTiO₄ crystallized in the space group P2₁/c with a=11.460(1), b=5.2920(4), c=5.3628(5) Å and β=90.441(9)°. The loaded protons were found to statistically occupy the sites around an apical oxygen of TiO₆ octahedron in the interlayer of these compounds, rather than Na atom sites in NaLnTiO₄.     

Uranium determination by133Xe in mineral separates from igneous rocks comparative study with fission track and thermal release characters of133Xe

Samples of an andesite (Asama-yama, Japan) and a basalt (Kilauea, Hawaii) were finely fractioned by density and the U distributions among the separates were determined by homogenized fission track method. Groundmass was found to be enriched with U; one half of the andesite U and almost all of the basalt U are accounted for by the groundmass U. Cerium and other REE are correlated with U. In the andesite separates Na is accompanied by these elements, but Fe and Co are rather anticorrelated. Uranium concentrations in the bulk samples and some of the separates were then compared with those determined by¹³³Xe extracted by heating at 1600°C. Fissiogenic¹³³Xe seems to become labile in groundmass, especially of the andesite, during reactor irradiations for 5 h or more. Stepwise heating experiments suggested that¹³³Xe in U-rich groundmass tends to escape at low temperatures and the remaining¹³³Xe is mostly retained in highly refractory sites in phenocryst rather poor in U.     

Crystallographic structures of two bisphosphonate:1-deoxyxylulose-5-phosphate reductoisomerase complexes

We have obtained the single-crystal X-ray crystallographic structures of the bisphosphonates [(1-isoquinolinylamino)methylene]-1,1-bisphosphonate and [[(5-chloro-2-pyridinyl)amino]methylene]-1,1-bisphosphonate, bound to the enzyme 1-deoxyxylulose-5-phosphate reductoisomerase (DXR, EC 1.1.1.267, also known as 2-C-methyl-d-erythritol-4-phosphate synthase), an important target for the development of antimalarial drugs. Our results indicate that both bisphosphonates bind into the fosmidomycin binding site. The aromatic groups are in a shallow hydrophobic pocket, and the phosphonate groups are involved in electrostatic interactions with Mg2+ or a cluster of carboxylic acid groups and lysine while the fosmidomycin phosphonate-binding site is occupied by a sulfate ion (as also observed in the DXR/NADP+ structure). The availability of these two new crystal structures opens up the possibility of the further development of bisphosphonates and related systems as DXR inhibitors and, potentially, as antiinfective agents.     

Kinetic study of the annealing of fission tracks in a Fe2O3KPO3 glass containing 100 ppm of uranium

The kinetics of the annealing of fission tracks in an artificial glass were studied using an optical microscope. The annealing experiments were performed in an electric furnace at 160–230°C for 15–160 min. The measurement of the fission tracks through an optical microscope was carried out after etching the annealed tracks with 10 N NaOH aqueous solution at 40°C. All reactions were found to be of first order within the annealing temperatures. An activation energy of 0.66 eV for the annealing reaction was obtained from the Arrhenius plot of the rate constants determined at 160, 190, 210, and 230°C.     

Neosidomycin,a new antibiotic of Streptomyces

A new indole-N-glycoside, neosidomycin (I), is produced by a strain belonging to Streptomyces hygroscopicus. The structure of I has been deduced from physico-chemical data obtained using the natural compound, its derivatives and products of degradation reactions.     

Thermochromism of poly-1-butene gels

Poly-1-butene gels in some solvents of benzene-derivatives show a colouring phenomenon. The colour changes from blue to yellow under irradiation of natural light as the temperature rises from the melting point of the solvent to the sol-gel transition temperature. The colouring phenomenon is due to selective scattering, but not to optical absorption. The apparent characteristics of the phenomenon resemble the thermochromism of cholesteric liquid crystals, although poly-1-butene itself is colourless and has no asymmetric carbons.