Detection of multiple anions by thin-layer chromatography

A novel detection method for 21 different anions by thin-layer chromatography is presented. Anions on the target plate form salts with amine in a developing solvent and are visualized after staining with citric acid-acetic anhydride reagent as white spots contrasting against a pale red-pink background. This method has particularly high sensitivity for anions of chlorate, sulfate, phosphate, chromate and dichromate (0.02-0.05 microg). The method is demonstrated to efficiently detect toxic arsenite in curry sauce as an example application. The proposed method offers highly efficient indirect detection for a wide range of anions, and serves as a purification procedure for the preparation of anionic sample solutions for other analytical methods.     

Alternate stranded triplex formation of chimeric DNA composed of tandem alpha- and beta-anomeric strands

A chimeric oligoDNA composed of a natural beta-anomeric oligonucleotide portion and an unnatural alpha-anomeric oligonucleotide portion forms an alternate stranded triplex possessing enhanced thermal stability compared to the triplexes composed of the parental oligomers.     

Photochemical processes induced by 157-nm light in H(2)-impregnated glassy SiO(2):OH

F(2) excimer-laser irradiation induces two major changes in SiO(2): OH glass impregnated with H(2) molecules. First, the vacuum-UV optical absorption edge is bleached, and the absorption at 157 nm decreases from 0.95 to 0.68 cm(-1) . Second, preexisting free SiOH groups and interstitial H(2) are photochemically converted to hydrogen-bonded hydroxyl groups. It is suggested that the bleaching of the UV-absorption edge is caused by a change of OH groups from a free to a hydrogen-bonded state and by photolysis of distorted Si-O bonds that are absorbing in the edge region.     

Circular dichroism in ferroelectric and antiferroelectric liquid crystals

Liquid crystal induced circular dichroism (LCICD) measurements were made to investigate the pretransitional phenomena in the S_A phase just above the S_A-S*_C and S_A-S*_CA phase transitions of both the first and the second order. The pretransitional LCICD in S_A was observed in the second order phase transition to S*_c and S*_cA, suggesting the existence of a dynamic helical structure in S_A. Such behaviour disappears when the transition is of the first order. It seems that the handedness of the dynamic helix in S_A is the same as that in S*_c even when the lower temperature phase is S*_cA. This is explained as a result of a dominant contribution of ferroelectric soft mode.     

Identification of a Single Phosphorylation Site Within Octopus Rhodopsin

Abstract— Light-dependent phosphorylation of rhodopsin (Rho) is a first step in the desensitization of the signaling state of the receptor during vertebrate and invertebrate visual transduction. We found that only ³⁵⁸Ser of the photoac-tivated octopus Rho (oRho*) was phosphorylated by octopus rhodopsin kinase (oRK). Tryptic truncation of the C-terminal PPQGY repeats of oRho that follow the phosphorylation region did not influence spectral or G-protein activation properties of oRho but abolished phos phorylation. Despite significant structural differences between oRK and mammalian RK, these results provide i further evidence of the importance of singly phosphorylated species of Rho* in the generation of arrestin binding sites.     

Supplementary Observations on the Chemistry of the Alkaloids of Berberine Series and Related Compounds. III. Fluorescence Spectra of the Alkaloids of Berberine Series and Their Related Compounds

The absorption maxima of the fluorescence spectra of the berberine series alkaloids are broadly distributed between 360 and 560 mμ. The fluorescence spectra of most substances of this series are very monotonous one having a single peak, the spectra of tetrahydrocoptisine and tetrahydroepiberberine are quite exceptional and consist of two wavy bands. The introduction of the auxochrome group into the molecule of “proto” compounds causes the decreasing of the fluorescence intensity and this effect is strongest in case of transition from protoberberine to berberine. That, tetrahydropalmatine does not show the distinct fluorescence spectrum band is the only incomprehensible fact.     

Semi-empirical LCAO-Xα theory for transition metal complexes. I. An outline of the theory

A semi-empirical theory for transition metal complexes is presented. Unusual aspects of the theory are (1) employment of Xα theory, (2) adoption of theoretical exchange parameter, (3) exclusion of (n + 1)s and (n + 1)p atomic orbitals of a nd-transition metal, and (4) variation of atomic orbitals in LCAO method. Also, an improved Mulliken approximation is proposed and used to simplify the LCAO-Xα equations.     

Effect of randomness on the ESR hyperfine structure of Cd+

The ESR spectra of the 5s¹ state of Cd⁺, induced with gamma-ray irradiation, were measured for polycrystalline CaO, β-Ca(PO₃)₂ and glassy Ca(PO₃)₂ matrices. It has been found out that one of the hyperfine absorptions due to the magnetic nuclei (¹¹¹Cd and ¹¹³Cd) reflects very senstively the structural fluctuation around the center in terms of pronounced line broadening. Such a feature was explained reasonably well by introducing the distribution of the hyperfine coupling constant. It was emphasized that Cd²⁺, the precursor of Cd⁺, is a very suitable probe to study the local randomness around Ca²⁺ in solids.