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1.
K Ichimura H Yamanaka K Chiba T Shinozuka Y Shiki K Saito S Kusano S Ameniya K Oyama Y Nozaki 《Journal of chromatography. A》1986,374(1):5-16
Until now, there has been little work covering all of the main native adrenal-cortical steroids in blood. We therefore established a method for the simultaneous quantitative measurement of 14 native adrenal-cortical steroids, which involves capillary column gas chromatography-mass spectrometry (GC--MS). Serum steroids were purified from serum with the Extrelut mini-column and then converted into stable derivatives for GC-MS by a combination of boronic cyclization and trimethylsilyl and methyloxime derivatization. The sensitivities (with a signal-to-noise ratio greater than or equal to 7) of our GC-MS method ranged from 0.1 to 1.0 ng/ml of serum, and the coefficients of variation of intra- and inter-assays were less than 19% for each steroid. Our newly devised method involving a capillary column GC-MS system has been proven to be a simple and suitable method for a diagnosis requiring simultaneous detection of many native adrenal steroids in clinical practice. The analysis time is only 4 h. 相似文献
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Phototriggered self-assembly of hydrogen-bonded rosette 总被引:2,自引:0,他引:2
Yagai S Nakajima T Karatsu T Saitow K Kitamura A 《Journal of the American Chemical Society》2004,126(37):11500-11508
Azobenzene-appended melamine M2 and barbiturate B2, both possessing bulky tridodecyloxyphenyl (TDP) wedge(s), were designed and synthesized to establish a photoresponsive hydrogen-bonded supramolecular assembly. The geometrical isomer EE-M2 bearing two E-azobenzene moieties easily complexed with B2, affording a remarkably stable cyclic hexamer EE-M2(3).B2(3) (rosette) in chloroform, toluene, and methylcyclohexane, as confirmed by size exclusion chromatography, dynamic light scattering, (1)H NMR, and UV-vis studies. The E --> Z photoisomerization of the azobenzene moieties upon irradiation with UV light was significantly suppressed in the rosette because of the steric crowding of the TDP wedges (total of nine TDP wedges in a rosette), whereas irradiation of the monomeric EE-M2 resulted in facile transformation into ZZ-M2 bearing two Z-azobenzene moieties. (1)H NMR studies of the complexation of the initially photogenerated ZZ-M2 with B2 revealed that it is hard for ZZ-M2 to form a rosette with B2 because of the intermolecular steric interaction between the TDP wedges. The photoregulatable complexation efficiency of M2 allowed us to accomplish the phototriggered formation of the rosette by irradiation of a monomeric mixture of ZZ-M2 and B2 using visible light. 相似文献
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Tatsuya Kikuchi Masumi Yoshida Shiki Matsuura Shungo Natsui Etsuji Tsuji Hiroki Habazaki Ryosuke O. Suzuki 《Journal of Physics and Chemistry of Solids》2014
Micro-, submicron-, and nano-scale titanium dioxide particles were reduced by reduction with a metallic calcium reductant in calcium chloride molten salt at 1173 K, and the reduction mechanism of the oxides by the calcium reductant was explored. These oxide particles, metallic calcium as a reducing agent, and calcium chloride as a molten salt were placed in a titanium crucible and heated under an argon atmosphere. Titanium dioxide was reduced to metallic titanium through a calcium titanate and lower titanium oxide, and the materials were sintered together to form a micro-porous titanium structure in molten salt at high temperature. The reduction rate of titanium dioxide was observed to increase with decreasing particle size; accordingly, the residual oxygen content in the reduced titanium decreases. The obtained micro-porous titanium appeared dark gray in color because of its low surface reflection. Micro-porous metallic titanium with a low oxygen content (0.42 wt%) and a large surface area (1.794 m2 g−1) can be successfully obtained by reduction under optimal conditions. 相似文献
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Hayate Saito Keita Yamamoto Yosuke Sumiya Ling‐Jun Liu Keisuke Nogi Satoshi Maeda Hideki Yorimitsu 《化学:亚洲杂志》2020,15(16):2442-2446
C?H iodination of aromatic compounds has been accomplished with the aid of sulfinyl directing groups under palladium catalysis. The reaction proceeds selectively at the peri‐position of polycyclic aryl sulfoxides or at the ortho‐position of phenyl sulfoxides. The iodination products can be further converted via iterative catalytic cross‐coupling at the expense of the C?I and C?S bonds. Computational studies suggest that peri‐C?H palladation would proceed via a non‐directed pathway, wherein neither of the sulfur nor oxygen atom of the sulfinyl group coordinates to the palladium before and at the transition state. 相似文献
6.
Kenji Sumiya Tsunetaka Matsumoto Seiji Watatani Fumttada Hayama 《Journal of Physics and Chemistry of Solids》1979,40(12):1097-1102
Highly coercive magnetic powder was obtained by growing cobalt ferrite on the surface of γ-Fe2O3 particles in highly alkaline suspensions containing cobalt and ferrous ions in a Co/Fe molar ratio = . The mechanism of the growth and the structure of cobalt ferrite on γ-Fe2O3 were studied by X-ray diffraction and electron diffraction techniques. Results show that crystals of cobalt ferrite CoFe2O4 with a spinel type crystal structure of lattice constant 8.415 Å grew epitaxially on γ-Fe2O3. The acicular direction of the epitaxially grown Co-γ-Fe2O3 as well as γ-Fe2O3 was in the [01] direction. It was found that from the lattice constant value and the half width of X-ray diffraction peaks, the lattice constant epitaxially grown Co γ-Fe2O3 may be attributed to two kinds of crystals, viz., seed γ-Fe2O3 () which was partly reduced to Fe3O4, and surface layer CoFe2O4 (). The crystal growth in the interface between the seed crystals and the growth layer was affected by the crystal structure of the seed crystals. The lattice constant of CoFe2O4 which was located in the vicinity of the interface was almost equal to that of the seed crystals. 相似文献
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