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81.
Chae SC Song JH Pounsambath P Yuan HY Lee JH Kim JJ Lee YC Chung HT 《Experimental & molecular medicine》2004,36(3):274-278
The family of T-cell immunoglobulin domain and mucin domain (TIM) proteins is identified to be expressed on T cells. A member of Tim family, Tim-3 (T cell immunoglobulin mucin 3) is selectively expressed on the surface of differentiated Th1 cells. Tim-3 might have an important role in the induction of autoimmune diseases by regulating macrophage activation and interacts with Tim-3 ligand to regulate Th1 responses. To determine the variation sites in the coding and promoter region of human Tim-3 gene, we performed variation scanning by direct sequencing using the genomic DNA isolated from the patients with asthma or allergic rhinitis and healthy controls without asthma and allergic rhinitis. We identified four single nucleotide polymorphisms (SNPs) including one novel SNPs (-1541C>T) and two variation sites (-1292_-1289delTAAA and -1282_-1278dupTAAAA) in the coding and promoter region of human Tim-3 gene in both the patients and healthy groups. 相似文献
82.
Determination of estrone and 17 beta-estradiol in human hair by gas chromatography-mass spectrometry
An efficient procedure is described for the determination of estrone and 17 beta-estradiol in hair by gas chromatography-mass spectrometry (GC-MS). The method involves alkyloxycarbonylation with isobutyl chloroformate (isoBCF) of phenolic hydroxy groups after alkaline digestion of hair samples. The resulting isobutyloxycarbonyl derivatives of estrone and 17 beta-estradiol are extracted with hexane and subjected to chlorodifluoroacetyl derivatization in order to protect the remaining alcoholic hydroxy groups. When GC-MS with selected ion monitoring (SIM) was used, the quantitative ions were at m/z 270 and 384 in the electron ionization mass spectra for estrone and 17 beta-estradiol, respectively. The detection limits for SIM of the steroids were 1 and 2 pg, respectively, and the SIM responses were linear with correlation coefficients varying from 0.991 to 0.994 in the concentration range 0.2-4.0 ng g-1 for the estrogens studied. The detection of estrone and 17 beta-estradiol in hair samples was possible in the concentration range of 0.24-1.30 ng g-1. The concentrations of the two estrogens detected were different in male and female hair samples. 相似文献
83.
Chester M. Mikulski Scott Grossman Chung Ja Lee Nicholas M. Karayannis 《Transition Metal Chemistry》1987,12(1):21-25
Summary Complexes of the general types Pd(L)(LH)Cl (LH=hxH, xnH, or tbH) and Pt(L)(LH)Cl3 (LH=hxH, or xnH) are formed by boiling under reflux 21 molar mixtures of hypoxanthine (hxH), xanthine (xnH) or theobromine (tbH) and PdCl2 or PtCl4 in ethanol-triethyl orthoformate. These complexes appear to be linear chain polymeric species, characterized by single monoanionic L– ligands bridging between adjacent Pd2+ or Pt4+ ions. Inclusion of one terminal neutral LH and one terminal chloro-ligand completes the coordination sphere in the square-planar Pd2+ complexes, while the Pt4+ complexes aretrans-octahedral, involving three terminal chloro and one terminal LH ligand per platinum. The possible binding sites of the bidentate bridging L– and the unidentate terminal LH are discussed. 相似文献
84.
The (2S,3R) isomer of 2-methoxymethyl-2,3-dideuterio-1-(dideuteriomethylene)cyclopropane has been synthesized and heated at 198.8°: from the experimentally observed mol fractions of the eight isomers of 2,3,α,α,- and 2,3,3,α - tetradeuterio - 2 - methoxymethyl - 1 - methylenecyclopropane in the pyrolysis product mixture have been derived rate constants for seven distinct modes of isomerization. One-center thermal epimerizations at C(2) and C(3) and the C(2)C(3) two-center epimerization are of kinetic importance. Only two of four observable stereochemical modes for carbon [1,3] shifts are seen: there is inversion of stereochemistry at the migrating C atom, while the C(3)H trans to C(2)-CH2OCH3 in starting material becomes syn 4 : 1 C(α)-H in the [1,3] shift product. Stereomutation at C(2) does not occur along the reaction coordinate for [1,3] carbon shifts. 相似文献
85.
Jo‐Nan Chen Fang‐Ming Hsu Hui‐Chun Wang Chung‐Wen Wu Pao‐Swu Cheng Wen‐Liang Tsai 《中国化学会会志》2006,53(4):931-938
Four series of compounds 11?50 containing terminal alicyclic rings such as cyclohexylmethyl, cyclopentylmethyl, cyclobutylmethyl, and cyclopropylmethyl rings were synthesized and their liquid crystal behavior studied. The ring size and the length of flexible alkoxy chain influence the phase formation in different ways. While the smaller ring and the shorter alkoxy chain tend to favor the formation of the N phase, the larger ring and the longer alkoxy chain tend to favor the formation of the SmC phase. All the compounds except 11 and 21 exhibit SmA phases. The widest temperature range of the N, SmA, and SmC phases are found in the compounds 41 , 46 , and 20 , respectively, which are 75 °C for 41 , 115 °C for 46 , and 100 °C for 20 . 相似文献
86.
Carbonate-selective membranes were prepared by incorporating a molecular tweezer-type carbonate-selective neutral carrier [N,N-dioctyl-3alpha,12alpha-bis(4-trifluoroacetylbenzyloxy)-5beta-cholan-24-amide] into a room temperature vulcanizing-type silicone rubber (3140 RTV-SR) matrix, and deposited on the planar-type electrodes (Pt containing Ag/AgCl electrodes formed on a ceramic plate) with and without an intermediary conducting polymer layer. Two types of solvent-soluble conducting polymers [poly(1-hexyl-3,4-dimethyl-2,5-pyrrolylene) or poly(3-octylthiophene-2,5-diyl)] have been examined as the solid contact material. Potentiometric properties of the resultant all-solid-state electrodes were evaluated in terms of their carbonate selectivity, response slope, potential stability and reproducibility. The sensitivity and carbonate selectivity of the SR membrane-based all-solid-state electrodes with conducting polymer solid contact were comparable to those of conventional electrodes. Experimental results also showed that the intermediary conducting polymer layer used in the all-solid-state electrodes greatly reduces the interference from dissolved oxygen. 相似文献
87.
In the capillary electrophoretic separation of primary amine enantiomers using (+)-(18-crown-6)-tetracarboxylic acid (18C6H4) as a chiral selector, the presence of run buffer constituents such as tris(hydroxymethyl)aminomethane (Tris) or Na+ competing with analytes for 18C6H4, diminishes the effectiveness of 18C6H4. In order to determine appropriate buffer systems for 18C6H4, various run buffer cationic components including Tris, 1,3-bis[tris(hydroxymethyl)methylamino]propane, bis(2-hydroxyethyl)iminotris(hydroxymethyl)methane, triethanolamine, tetramethylammonium, and Na+ were compared. Quantitative studies of the effects of the competitive constituents were carried out by measuring the electrophoretic mobilities of histidine as a function of the 18C6H4 concentration. We also derived a simple equation to estimate the optimal chiral selector concentration for a maximum mobility difference in the presence of a competitive inhibitor. 相似文献
88.
An unusually stable molecular capsule was formed by heating phenyleneurea-spanned resorcinarene cavitand with 4-methyl-N-p-tolylbenzamide. The molecular capsule behaved as a discrete molecular entity showing a cylindrical D(4d) structure and showed no guest exchange in toluene-d(8) even at 100 degrees C. [structure: see text] 相似文献
89.
Stevens SM Chung AY Chow MC McClung SH Strachan CN Harmon AC Denslow ND Prokai L 《Rapid communications in mass spectrometry : RCM》2005,19(15):2157-2162
A fluorescent affinity tag (FAT) was synthesized and was utilized to selectively modify phosphorylated serine and threonine residues via beta-elimination and Michael addition chemistries in a 'one-step' reaction. This labeling technique was used for covalent modification of both phosphoproteins and phosphopeptides, allowing identification of these molecular species by fluorescence imaging after solution- or gel-based separation methods. In addition to the strong fluorescence of the rhodamine tag, a commercially available antibody can be used to enrich low-abundance post-labeled phosphopeptides present in complex mixtures. Application of this methodology to phosphorylation-site mapping has been evaluated for a phosphoprotein standard, bovine beta-casein. Initial results demonstrated low femtomole detection limits after fluorescence image analysis of FAT-labeled proteins or peptides. 相似文献
90.
Yong-Sam Chung Sun-Ha Kim Moon Jong-Hwa Young-Jin Kim Jong-Myoung Lim Jin-Hong Lee 《Journal of Radioanalytical and Nuclear Chemistry》2005,267(1):95-107
Summary As part of an air pollution monitoring study, airborne particulate matter (PM2/PM10-2) samples were collected from 2000 to 2003 at two sampling sites in an urban region, Daejeon, the middle of Korea. Mass concentrations
of both fine and coarse fractions and that of the black carbon in the fine particles were measured using the Gent stacked
filter unit sampler and the smoke stain reflectometer, respectively. In the collected samples the concentrations of 24 elements
were analyzed using instrumental neutron activation analysis. Monitored data were investigated for their temporal trends under
different environmental conditions and their seasonal correlation patterns. Crustal enrichment factors were also estimated
to establish the contribution between anthropogenic and crustal origin. Patterns for airborne particle matter (APM) and elemental
concentrations, seasonal variation of some marker elements were investigated. The results can be applied for the investigation
of further air pollution sources and for the evaluation of air quality. 相似文献