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Hiroyuki Terashima Yui Mutoh Sen-ichi Aizawa Atsushi Taga Ikko Mikami Yutaka Itabashi Kaname Tsutsumiuchi Atsushi Yamamoto Shuji Kodama 《Journal of separation science》2023,46(6):2200827
Abscisic acid (2-cis,4-trans-abscisic acid) is a plant hormone that has an asymmetric carbon atom. We tried to separate the enantiomers of native abscisic acid by HPLC using a phenyl column and a chiral mobile phase containing γ-cyclodextrin. The optimum mobile phase conditions were found to be 0.8% (w/v) γ-cyclodextrin, 4% (v/v) acetonitrile, and 20 mM phosphate buffer (pH 6.0). It was found that (R)-abscisic acid was earlier detected than (S)-abscisic acid. Since γ-cyclodextrin is hardly retained on a phenyl column, it was suggested that (R)-abscisic acid formed a more stable complex with γ-cyclodextrin than the (S)-abscisic acid. Abscisic acid in an acacia honey sample was successfully enantioseparated with the proposed method and only (S)-abscisic acid was detected. A biologically inactive 2-trans,4-trans-abscisic acid, which was prepared by irradiation of abscisic acid with a light-emitting diode lamp at 365 nm, was partially enantioseparated by the proposed method. Since the irradiation of (S)-abscisic acid-induced cis-to-trans isomerization to produce one 2-trans,4-trans-abscisic acid enantiomer, it is reasonable that racemization did not proceed during the cis-to-trans isomerization. (S)-Abscisic acid and probably (S)-2-trans,4-trans-abscisic acid were detected in a honey sample, where the peak area of (S)-abscisic acid was 7 times larger than that of (S)-2-trans,4-trans-abscisic acid. 相似文献
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Kazuhisa Fujimoto Dr. Sayaka Aizawa Ikko Oota Junya Chiba Dr. Masahiko Inouye Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(8):2401-2406
We have developed an induced circular dichroism (ICD) probe with a chromophore‐linked alkynyldeoxyribose skeleton for analyzing higher‐order structures of DNA duplexes in the visible‐light region. When CG‐repeated oligonucleotides (ODNs) with the probe at their 5′ ends adopted Z‐form duplexes at a high NaCl concentration, strong ICD signals were observed at the absorptive region of the chromophore. On the other hand, their B‐form duplexes, formed at a low NaCl concentration, produced a faint ICD signal. The specific ICD for the Z‐form duplexes was found to appear only when the chromophores were attached at the 5′ ends of each of the ODNs. Furthermore, the chromophoric alkynylnucleoside residues effectively promoted the B to Z transition of the ODN. 相似文献
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A. Oota H. Matsui M. Funakura J. Iwaya K. Mitsuyama 《Physica C: Superconductivity and its Applications》1993,210(3-4):489-501
The influence of the sintering conditions on the microstructure and critical current density Jc has been studied on screen-printed Ag-(Bi, Pb)2Sr2Ca2Cu3Ox tapes with a ceramics mono-layer core. Three kinds of fabrication processes, which consist of a combination of cold working (rolling and/or pressing) and sintering, are applied. Four times repetition of pressing and sintering after the pre-sintering produces the highest c-axis alignment and achieves Jc= 1.5 × 104 A/cm2 (77 K, 0 T). The Jc versus θ data with an angle θ between B and the c-axis elucidate the relation between the anisotropy ratio γ=Jc(Bc)/Jc(B|c and the half-height angular width Δθ of a peak for Bc. This is related to both grain alignment and the Jc value. An increase in Jc, which comes from an improvement for grain alignment, enhances γ and narrows Δθ. The Jc versus θ data are fitted to the expression Jc(B, θ)=J c(B, 90°)/[(γ−1)|cos θ|n+1] by regarding both γ and n as adjustable parameters. Fabrication of screen-printed tapes with multilayers (1≤N≤5) is presented, where the critical current increases from 8.0 A to 30.2 A at 77 K and 0 T as N increases. 相似文献
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The yellow compound pyoverdin was isolated from the bacteria Pseudomonas chlororaphis, isolated from mud in Japan. A study of the effects of iron, phosphorus, manganese and zinc on degradation of triphenyltin (TPT) by pyoverdin (20 mg) was carried out in distilled water (30 ml) containing 6 µg l?1 concentration of TPT at 20 °C for 48 or 96 h. The organotins in water were analyzed by gas chromatograph–mass spectrometry in the selected ion mode. The degradation of TPT by pyoverdin decreased with increase of phosphorus at 0–35 mg l?1 and Fe‐EDTA at 0–2 mg l?1 concentrations. Also, degradation of diphenyltin by pyoverdin decreased with increase of Mn‐EDTA at 0–1 mg l?1 and Zn‐EDTA at 0–1 mg l?1. On the other hand, degradation of TPT by pyoverdin was found to be unaffected by manganese and zinc in water. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
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A spectrofluorimetric method for the separate assay of two subgroups of rat liver phenol sulphotransferases (PSTs I and II and PSTs III and IV) has been established. The method is based on the enzyme reaction using two different concentrations of p-hydroxybenzaldehyde (10 μM for PSTs III/IV and 3 mM for PSTs I/II) as the substrate and the spectrofluorimetric determination of the product p-formylphenyl sulphate by means of its reaction with 1,4-dimethyl-3-carbamoylpyridinium chloride, a selective reagent for aromatic aldehydes without free phenolic hydroxy groups. The detection limit of the sulphate is 50–70 pmol in the enzyme reaction mixutre. The Km values for p-hydroxybenzaldehyde with PSTs I/II and III/IV were 1.1 mM and 2.1 μM, respectively. The effects of growth and of dexamethasone treatment of rats on the liver PST activities were also studied. 相似文献