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排序方式: 共有273条查询结果,搜索用时 15 毫秒
1.
Copper(II) is determined by non-extractive spectrophotometry as a complex of butylene dithiocarbamate formed in situ by reaction between carbon disulfide and pyrrolidine in aqueous Triton X-100 medium. This method is similar to that with butylene dithiocarbamate as starting material in the sense of simplicity, sensitivity, precision and accuracy. Pyrrolidine is the best of seven secondary amines tested in this way for copper determinations. 相似文献
2.
3.
Kenjiro Hattori Tomoko Takeuchi Mika Ogata Ayumi Takanohashi Katsuhiko Mikuni Katsuyoshi Nakanishi Hideo Imata 《Journal of inclusion phenomena and macrocyclic chemistry》2007,57(1-4):339-342
We obtained the association constants Ka of estrogen (E2) and environmental chemicals by the surface plasmon resonance (SPR) assay using the immobilized mono-6-O-α-maltosyl-β-CD (G2βCD) compared with the immobilized β-CD and the immobilized estrogen receptor (ER). The association behavior of G2βCD was shown as a ER model compound. The calibration curve was determined by the initial rate of association depending on
the various concentrations, and the minimum detectable concentrations in the order of parts per billion were calculated. The
SPR assay has advantages that the pre-treatment of the sample is not necessary and the immobilized ligand is stable and useful
for the repeated measurement. 相似文献
4.
The present study is concerned with the extraction behavior and equilibrium of Pd(II) with 2-methyl-8-quinolinol (HMQ) into supercritical fluid CO(2) (SF-CO(2)). Pd(II)-HMQ complex extracted from a weakly acidic solution (pH 2-3) into SF-CO(2) was determined to be Pd(MQ)(2) on the basis of a slope analysis. The extraction constant K(ex,SF) (=[Pd(MQ)(2)](SF)[H(+)](2)[Cl(-)](4)[PdCl(4)(2-)](-1)[HMQ](-2)) was determined to be 10(4.3+/-0.2) at 8.5 MPa, 45 degrees C and I=0.4 M (H,Na)Cl (1 M=1 mol dm(-3)). The distribution behavior of HMQ between an aqueous and a SF-CO(2) phase was examined so as to discuss quantitatively the extraction equilibrium. The extraction constant (K(ex,Cy)) of Pd(II) with HMQ into cyclohexane with a similar polarity to SF-CO(2) was determined and the K(ex,SF) was compared with the K(ex,Cy). Pd(II) at the concentration range of 10(-5)-10(-4) M in the aqueous solution (pH<3) containing relatively high concentration of chloride ion was found to be extracted efficiently by the SF-CO(2) extraction. 相似文献
5.
Jun Suzuki Kenjiro Fujimoto Toshiyuki Mori Mamoru Watanabe Yoshio Hasegawa 《Journal of Sol-Gel Science and Technology》2000,19(1-3):775-778
The photocatalytic reduction of nitrogen monoxide (NO) with ethane on the hollandite type catalyst (K2Ga2Sn6O16KGSO) was investigated. Using a closed-gas circulating system equipped with a Q-MASS detector and in-situ diffuse reflectance FT-IR spectroscopy. The reactant gases of NO and 13C2H6 decreased with the increasing irradiation time. In contrast, the N2 yield increased proportionally to the conversion of 13C2H6. Nitrogen oxides such as N2O did not reach their detectable levels. The NO adsorbed on KGSO was found to change to its activated species by UV irradiation. The oxidized products of C2H6 such as CH3CHO increased in proportion to the reaction time. The present results strongly suggest that KGSO has remarkable photocatalytic activity for the reduction of NO with C2H6. 相似文献
6.
Kenneth E. Laintz Shuichi Iso Yoshiro Meguro Zenko Yoshida 《Journal of separation science》1994,17(8):603-606
The chromatographic behaviors of lanthanide chelates of acetylacetone (ACAC), trifluoroacetylacetone (TFA), thenoyltrifluoroacetone (TTA), dipivaloylmethane (THD), 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedione (FOD), and the thenoyltrifluoroacetonepyridine (TTA·Py) adduct were investigated using packed column supercritical fluid chromatography. Mobile phases consisting of neat and alcohol modified CO2 were used with a phenyl packed stationary phase. Lanthanide complexes of ACAC, THD, and FOD were shown to have better chromatographic performance compared to the corresponding chelates with TFA, TTA, and TTA·Py. In particular, TTA complexes such as Eu(TTA)3 showed characteristic thermal decomposition in the mobile phase at elevated temperature. In addition, retention behavior was found to be a temperature dependent function of volatility and solubility for all chelates studied. 相似文献
7.
Satoshi Yoshikawa Minoru Ueno Kenjiro Meguro 《Journal of polymer science. Part A, Polymer chemistry》1979,17(8):2491-2497
The monolayer properties of poly(n-stearyl methacrylate), poly(n-lauryl methacrylate), and their mixtures at various ratios of the two polymers have been studied from the measurements of their surface pressure–area isotherms at air–water interface. The monolayer properties of their mixtures have been compared with those of their corresponding copolymers. The results show that the isotherms of the mixed monolayers have two break points at higher pressures than that of poly(n-lauryl methacrylate). This suggests that the mixtures may form more stable films that consist of separate phases of the two homopolymers, although each phase may contain a small amount of the other. The isotherms of the copolymer monolayers indicate a phase transition from liquid condensed to solid film between 50 segment mole % and 70% poly(n-stearyl methacrylate). The monclayer of these copolymers has properties that differ from those of the corresponding mixtures of two pure homopolymers and is more compatible than the mixtures of pure homopolymers. 相似文献
8.
Abstract-A number of carboxylic acid derivatives of the photoactive terthiophene, α-terthienyl, were found to possess impressive UVA-dependent activity against the human immunodeficiency virus, HIV-1; but only when assayed in the absence of serum, indicating that the latter contained interfering components. Good antiviral activity required a high rate of singlet oxygen production, in accordance with previous observations on thiophenes. 相似文献
9.
Kenjiro Hattori Akira Kenmoku Tsukasa Mizuguchi Daisuke Ikeda Mamoru Mizuno Toshiyuki Inazu 《Journal of inclusion phenomena and macrocyclic chemistry》2006,56(1-2):9-16
A synthetic series of heptakis-galactose-branched cyclodextrins (termed CDs) having a longer spacer arm using two amino-caproic acids as an enlarging unit were prepared. Starting with heptakis-amino-β-CD or heptakis-amino-caproic-amide-β-CD, treated with galactosyl-glucono-amide-caproic acid, the new compounds heptakis (Gal-cap1)-CD (4) or heptakis (Gal-cap2)-CD (5) were obtained. The longer galactose spacer arm extremely favors the PNA association. The effect of branch length on K with PNA was enhanced up to 138-fold 3 as well as with DXR enhanced up to 81-fold. Hexakis (Gal-cap2)-CD (6) was prepared and the association constants with rat liver cells were observed to be 2.5 × 1010 M−1. A multi-high mannose type oligosaccharide branched CD (7) showed a large association constant with DXR up to 1.1 × 109 M−1. The two-dimensional map for the association constants of newly synthesized oligosaccharide-branched CDs toward lectin or liver cells versus the association constants toward a drug (doxorubicin) suggested a method of finding a better targeting drug carrier. The structural effect of the oligosaccharide-CDs showed that the number and length of the branch were dominant factors in designing for enhanced dual recognition. 相似文献
10.
Stratum corneum (SC) lipids are of particular importance in maintaining the permeability barrier function. Although many studies have demonstrated that UVB irradiation of mammalian skin reduces barrier function, the responsible alterations in SC lipid profiles are not known. In this study, we investigated both compositional and morphological alterations in SC lipids with the development of barrier abnormalities caused by daily UVB irradiation in hairless rat skin. The UVB irradiation of suberythemal doses (0.5 minimal erythema dose) significantly increased transepidermal water loss (TEWL) relative to nonirradiated control, indicating a diminished barrier function. Under these conditions, the total amounts of major SC lipid species (ceramides, cholesterol, free fatty acids) in UVB-irradiated SC did not differ from those in nonirradiated SC. However, electron microscopic observations revealed marked abnormalities in the intercellular domains of UVB-irradiated SC, where naturally occurring intercellular multilamellar structures were often absent and leaving the area with the appearance of an empty space. Moreover, in UVB-irradiated SC, individual corneocytes often showed small amounts of intercellular deposition product with abnormal lamellar structure, where lamellar body sphingomyelinase activity was present. These observations demonstrated a partial failure of lamellar body secretion in UVB-irradiated SC and suggested that a defect in the secretion of lamellar body-derived lipids and enzymes to SC intercellular space is, at least in part, responsible for the observed abnormal intercellular structure and barrier disruption. 相似文献