Laser Spectroscopy of the CCO Radical in the 0.77-μm Region: Analysis of theÃ(020)κΠ andÃΠi(001) States

TheÃ(020)κ³Π–X³Σ⁻(000) andóΠ_i(001)–X³Σ⁻(000) bands of the CCO radical have been investigated by laser spectroscopy with two types of tunable laser system. An analysis was made simultaneously for both the bands to establish line assignments and determine molecular constants for both theÃ(020) andÃ(001) states. A coupling constant between these two states was also determined by assuming the interaction to be of Fermi type.     

带弦的圈是协调图

称具有ｅ条边的简单图Ｇ为协调图，若存在由Ｇ的顶点集到模ｅ的整数群Ｚｅ的一个单射ｈ，使得导出映射ｈ＾＊：ｈ＾＊（ｕｖ）≡ｈ（ｕ）＋ｈ（ｖ）（ｍｏｄ ｅ）是一个由Ｇ的边集到Ｚｅ的双射，带弦的圈Ｃ′ｎ是由含ｎ个顶点的圈Ｃｎ上添一条连结两个不相邻顶点的边而得到的图。本文中证明了，除了ｎ＝６且弦端点在Ｃｎ上的距离为２的情况外，所有带弦的圈都是协调图。     

Highly sensitive colour change system within slight differences in metal ion concentrations based on homo-binuclear complex formation equilibrium for visual threshold detection of trace metal ions

A new technique of expressing slight differences in metal ion concentrations by clear difference in colour was established for visual threshold detection of trace metal ions. The proposed method is based on rapid change of the mole fraction of the homo-binuclear complex (M₂L) about a ligand in a narrow range of the total metal ion concentration (M_T) in a small excess, in case the second metal ion is bound to the reagent molecule which can bind two metal ions. Theoretical simulations showed that the highly sensitive colour change within slight differences in metal ion concentrations would be realized under the following conditions: (i) both of the stepwise formation constants of complex species are sufficiently large; (ii) the stepwise formation constant of the 1:1 complex (ML) is larger than that of M₂L; and (iii) the absorption spectrum of M₂L is far apart from the other species in the visible region. Furthermore, the boundary of the colour region in M_T would be readily controlled by the total ligand concentration (L_T). Based on this theory, the proposed model was verified with the 3,3′-bis[bis(carboxymethyl)amino]methyl derivatives of sulphonephthalein dyes such as xylenol orange (XO), methylthymol blue (MTB), and methylxylenol blue (MXB), which can bind two metal ions at both ends of a π-electron conjugated system. The above-mentioned model was proved with the iron(III)-XO system at pH 2. In addition, MTB and MXB were suitable reagents for the visual threshold detection of trivalent metal ions such as iron(III), aluminium(III), gallium(III) and indium(III) ion in slightly acidic media. The proposed method has been applied successfully as a screening test for aluminium(III) ion in river water sampled at the downstream area of an old mine.     

Levels in 74Se, 78, 80Kr and 84Sr and systematics of quasi-γ bands

Quasi-band structures in ⁷⁴Se, ^{78, 80}Kr and ⁸⁴Sr have been investigated using (p, 2nγ) reactions. The members of the quasi-γ band have been observed up to 5⁺ in ⁷⁴Se, ^{78, 80}Kr and up to 3⁺ in⁸⁴Sr. The analyses of the energy systematics of the quasi-γ bands studied in this mass region as well as in other regions make clear the evolution of the quasi-γ band to the γ-band in well-deformed nuclei. In addition to these positive-parity bands, negative-parity levels were observed in ⁷⁴Se, ⁸⁰Kr and ⁸⁴Sr.     

Determination of diphenylarsinic acid and phenylarsonic acid,the degradation products of organoarsenic chemical warfare agents,in well water by HPLC–ICP‐MS

Diphenylarsinic acid (DPAA) and phenylarsonic acid (PAA), which were degradation products of organoarsenic chemical warfare agents used as sternutatory gas, were detected in the well water at Kamisu, Ibaraki Prefecture, Japan. The standard material of DPAA was synthesized with aqueous arsenic acid and phenylhydrazine in order to determine organic arsenic compounds in well water. The DPAA showed a protonated ion at m/z 263 [M + H]⁺ and a loss of H₂O ion at m/z 245 [M + H ? H₂O]⁺ from protonated ion by the electrospray ionization time‐of‐flight mass spectrometry. The quantitative analysis of DPAA and PAA was performed by high‐performance liquid chromatography inductively coupled plasma mass spectrometry and the system worked well for limpid liquid samples such as well water. Copyright © 2005 John Wiley & Sons, Ltd.     

Self-association of telomeric short oligodeoxyribonucleotides containing a dG cluster.

Oligonucleotides containing a dG cluster, d(TmGnTm), are models of single-stranded parts of telomeric deoxyribonucleic acid and substitutes for poly(dG). Electrophoretic and spectroscopic analyses of the oligomers indicate that the oligomers can form two alternative structures, single- and quadruple-stranded helices, in solution at room temperature. The transformation of the single-strandef form into the quadruple-stranded form or vice versa is undetectable in 0.1 M NaCl at 4.3 x 10(-5) M strand concentration at room temperature. However, at a 50-fold higher strand concentration, the single-stranded oligomer is gradually converted into the quadruplex. An increase in ionic strength stabilizes the single-stranded structure, so it seems to inhibit the formation of the quadruplex. The quadruplex, [d(TTGGGGTT)]4, is resistant to denaturation in 7 M urea, in which the Watson-Crick type d(TTGGGGTT).d(AACCCCAA) duplex dissociates. An increase in the number of T residues facilitates the dissociation of the quadruplex by heating. Thus the number of T residues surrounding the dG cluster might control the rigidity of the quadruplex structure.     

Investigation of neutron deficient nuclei in the region 28<N,Z <50 with the help of heavy ion compound reactions

In-beamγ ray spectroscopy withγ singles spectra,γγ coincidences andγ ray angular distributions has been performed with several target-projectile combinations:^natCa +³²S,^natCa +⁴⁰Ca,⁵⁴Fe +¹⁴N,⁵⁸Ni +¹²C,⁵⁸Ni +¹⁴N,⁶⁶Zn +¹⁶O,⁶⁸Zn +¹⁶O. Level schemes of⁶⁶Ge,⁶⁸Ge,⁶⁹As,⁷⁰Se,⁷⁴Kr,⁸⁰Sr and⁸²Sr have been deduced. The following level energies and spin-parity assignments have been found:⁶⁶Ge: 957.4 keV, 2⁺; 1693.7; 2174.7, (4⁺); 3685.7; 4207.5;⁶⁸Ge: 1015.8, 2⁺; 1777.9, 2⁺; 2267.9, 4⁺; 2428.8, 3(⁺); 2649.1, 3^?; 3582.3, (5^?); 3649.3, (5^?); 3696.2, (6⁺); 3883.3, (6^?); 4054.4, (7^?); 4454.6; 4837.3;⁶⁹As: 98.2; 164.6;789.6;863.2; 1306;2160;2210.4;2831.5;3258.3;3263.5;3991.1;5195.7;⁷⁰Se: 945.4, 2⁺; 1600.9; 2039.4, (4⁺);⁷⁴Kr: 455.7, 2⁺; 1013.5, (4⁺); 1781.5;⁸⁰Sr: 385.4, 2⁺; 980.2, (4⁺); 1763.2, (6⁺);⁸²Sr: 573.4, 2⁺; 1328.5,(4⁺); 2229.6,(6⁺). γ ray activity spectra have been measured after the bombardment of natural Ca with³²S. The half-life of the new isotope⁶⁹Se has been found to be 27±3 sec. Recoil distance Doppler-shift measurements have been performed with the reactions^62,64Ni,⁶⁶zn(¹⁶O, 2n)^{76, 78} Kr,⁸⁰Sr. The following half-lives have been determined:⁷⁶Kr: 423.8 keV, 2⁺, 37±5 psec; 1034.2,4⁺, 5.7±1.6;⁷⁸Kr: 455.3, 2⁺, 25±3; 1120.0, 4⁺, 3.8±1;⁸⁰Sr: 385.4, 2⁺, 44±6. The energy and half-life systematics of the first excited state of even-even nuclei suggest a maximum of nuclear deformation in the region 28≦N, Z≦50 near ₃₈ ⁷⁶ Sr₃₈ or ₄₀ ⁷⁸ Zr₃₈.     

δ-Lactone formation from δ-hydroxy-trans-α,β-unsaturated carboxylic acids accompanied by trans-cis isomerization: synthesis of (−)-tetra-O-acetylosmundalin

(±)-(4,5-anti)-4-Benzyloxy-5-hydroxy-(2E)-hexenoic acid 6 was subjected to δ-lactonization in the presence of 2,4,6-trichlorobenzoyl chloride and pyridine to give the α,β-unsaturated-δ-lactone congener (±)-7 (87% yield) accompanied by trans-cis isomerization. This δ-lactonization procedure was applied to the chiral synthesis of (+)-(4S,5R)-7 or (−)-(4R,5S)-7 from the chiral starting material (+)-(4S,5R)-6 or (−)-(4R,5S)-6. Deprotection of the benzyl group in (+)-(4S,5R)-7 or (−)-(4R,5S)-7 by the AlCl₃/m-xylene system gave the natural osmundalactone (+)-(4S,5R)-5 or (−)-(4R,5S)-5 in good yield, respectively. Condensation of (−)-(4R,5S)-5 and tetraacetyl-β-d-glucosyltrichloroimidate 22 in the presence of BF₃·Et₂O afforded the condensation product (−)-8 (97% yield), which was identical to tetra-O-acetylosmundalin (−)-8 derived from natural osmundalin 9.     

Monte Carlo calculation of second and third virial coefficients of small-scale comb polymers on lattice

This paper reports the first computational estimation of the comb polymers' third virial coefficients. The number of the chains in the comb polymers range from 5 to 11. An algorithm that counts the contributing terms of the third virial coefficients in an accelerated manner is presented along with its efficiency dependence on the polymers' size. In addition, the second virial coefficients are estimated for the comb polymers and compared to previously reported results.     

Rapid Analysis of Ingredients in Cream Using Ultrasonic Mist–Direct Analysis in Real-Time Time-of-Flight Mass Spectrometry

A novel method for the simultaneous detection of ingredients in pharmaceutical applications such as creams and lotions was developed. An ultrasonic atomizer has been used to produce a mist containing ingredients. The analyte molecules in the mist can be ionized by using direct analysis in real time (DART) at lower temperature than traditionally used, and we thus solved the problem of normal DART-MS measurement using a high-temperature gas. Thereby, molecular-related ions of heat-unstable components and nonvolatile components became detectable. The deprotonated molecular ion of glycyrrhizic acid (m/z 821), which is unstable at high temperatures, was detected without pyrolysis by ultrasonic mist–DART-MS using unheated helium gas, although it was not detected by normal DART-MS using heated helium gas. The cationized molecular ions of derivatives of polyethylene glycol fatty acid monoesters, which are nonvolatile compounds, were also detected as m/z peaks observed from 800 to 2300. Although the protonated molecular ion of tocopherol acetate was not detected in ionization by ultrasonic mist, it was detected by ultrasonic mist–DART-MS even in the emulsion. It was not necessary to dissolve a sample completely to detect its ions. This method enabled us to obtain the composition of pharmaceutical applications simply and rapidly.

Open image in new window

Graphical Abstract ?