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71.
The suitability of thallium halide electrodeless discharge tubes as a radiation source for atomic fluorescence was investigated. Effects of various parameters, affecting the emission intensities, were investigated. 相似文献
72.
An enzyme-linked immunometric assay for cortisol based on idiotype-anti-idiotype reactions 总被引:1,自引:0,他引:1
Cortisol levels in body fluids are useful for monitoring the function of the pituitary-adrenal axis. Here, we established an “enzyme-linked immunometric assay” (a noncompetitive-type ELISA) for cortisol based on idiotype-anti-idiotype reactions. Six different anti-idiotype monoclonal antibodies that recognized the variable regions of a newly established anti-cortisol antibody were generated using hybridoma technology; these were two β-type and four α-type anti-idiotype antibodies, recognizing the paratope and framework regions, respectively. An immunometric assay was established using a combination of a selected α-type and a selected β-type antibody. The analyte (cortisol) was captured by an excess amount of anti-cortisol antibody immobilized on microplates, and the unoccupied paratope was saturated with the β-type antibody. Hapten-occupied anti-cortisol antibody, with less steric hindrance, was then selectively bound by the α-type antibody, labeled with biotin. The amount of biotin residue on the microplates was colorimetrically monitored using a peroxidase-labeled streptavidin. This assay had an approximately threefold higher sensitivity (detection limit: 90 pg = 248 fmol cortisol) than a competitive ELISA using the same anti-cortisol antibody, as well as a practical specificity for providing reasonable determination of normal urinary cortisol levels. 相似文献
73.
The synthesis of benzothiazolylideneacetates and 1,4-benzothiazine was found to be highly controllable via simple exchange of corresponding oxidants. It turned out that the treatment of benzothiazolylacetates with m-CPBA gave 1,4-benzothiazines via oxidative ring expansion process, and with DDQ gave benzothiazolylideneacetates via dehydrogenation, in good yield, respectively. The structures of both skeletons were confirmed by their X-ray diffractions. A previously reported method for the synthesis of benzothiazolylideneacetates was thus proved to be incorrect. 相似文献
74.
Thermally-induced optical bistability with two holding beams has been experimentally investigated in a metal-dielectric-metal interference mirror. Steady-state responses different from the usual S-shaped curve and with potential interest for composite logic operations are reported. 相似文献
75.
76.
We present arguments supporting the conjecture that anomalous prompt photons observed recently in muon-proton interactions by the European Muon Collaboration (EMC) at CERN are of the same dynamical origin as low mass lepton pairs produced in hadronic collisions. The EMC data are found to be in a qualitative agreement with the soft annihilation model. The conjecture implies that the rate of anomalous photon production depends quadratically on the rapidity density of secondary hadrons in the rapidity region of the photon. A study of this dependence is suggested as a crucial test of the conjecture. 相似文献
77.
78.
Norihiro Kobayashi Pi Sun Yayoi Fujimaki Toshifumi Niwa Tadashi Nishio Junichi Goto Hiroshi Hosoda 《Analytical sciences》2002,18(12):1309-1314
Measurement of cortisol levels in body fluids is important for monitoring pituitary gland and adrenal functions. To develop a specific and standardized enzyme-linked immunosorbent assay (ELISA), a novel monoclonal anti-cortisol antibody has been generated using a reasonably designed haptenic derivative. Spleen cells were prepared from the BALB/c or A/J mouse, which had repeatedly been immunized with a conjugate of 4-(2-carboxyethylthio)cortisol (CET) and bovine serum albumin, to be fused with P3/NS1/1-Ag4-1 myeloma cells. After four fusion experiments, one hybridoma clone secreting a practical antibody has been established. The resulting monoclonal antibody CS#38 (isotype gamma1, kappa) showed an affinity constant (K(a)) for cortisol of 1 x 10(9) M(-1) and provided a practical calibration curve (detection limit, 0.26 ng per assay) in a homologous ELISA system employing horseradish peroxidase-labeled CET as a labeled antigen. Cross-reactivities with related C-21 steroids were acceptably low: 11-deoxycortisol (4.3%), cortisone (4.0%), corticosterone (1.9%), progesterone (1.6%), 17alpha-hydroxyprogesterone (12%), 6beta-hydroxycortisol (8.4%), and tetrahydrocortisol (< 0.1%). Urinary and serum cortisol levels of healthy volunteers were determined by this method after methylene chloride extraction to be 39.0 +/- 17.0 microg/day (n = 7) and 80.8 +/- 38.9 ng/mL (n = 10), respectively, both of which are in the reference range. 相似文献
79.
Luis E. Piñero Carmelo García Virginie Lhiaubet‐Vallet Rolando Oyola Miguel A. Miranda 《Photochemistry and photobiology》2009,85(4):895-900
Chlorprothixene (CPTX, Taractan®) is a low potency antipsychotic mainly used for the treatment of psychotic disorders (e.g. schizophrenia) and acute mania occurring as part of bipolar disorders. As in the case of other numerous drugs used in the treatment of psychiatric disorders, CPTX presents geometric isomerism. Therefore, in vitro irradiation induces a rapid Z/E isomerization, which can affect its pharmacokinetic properties. This photoisomerization is not dependent on the oxygen concentration. The Z/E quantum yields determined for zCPTX in acetonitrile are 0.22 and 0.21 in anaerobic and aerobic environments, respectively. In the presence of water, both isomers decompose to produce 2‐chlorothioxanthone (CTX) after prolonged irradiation. This process strongly depends on the water concentration and the irradiation time, i.e. it is autocatalyzed by the CTX through a triplet‐energy transfer mechanism. The protonation state of the terminal amino group, on the other hand, has no effect on the isomerization process, but inhibits the formation of CTX. These results indicate that the phototoxicity of zCPTX is somehow affected by the formation of CTX. 相似文献
80.
在模拟生理条件下,运用荧光光谱、激光闪光光解(LFP)和分子对接等技术研究了8种具有抗肿瘤活性的嘧啶衍生物(PDs,其中PDs A 5-FU为成药,PDs B-H为实验室自制)与人血清白蛋白(HSA)的相互作用.利用Stern-Volmer方程和激光闪光光解技术分析了PDs对HSA的荧光猝灭机制,PDs A和B为静态猝灭,PDs G和H为动态猝灭.用双倒数曲线法得出5种PDs与HSA的结合常数Ka和结合位点数n,在测定条件下5种PDs与载体结合位点数均为1,且均以弱结合力结合,通过热力学参数ΔH,ΔS和ΔG推测出PDs B,C和E与HSA之间的作用力为静电作用力和疏水作用力,PDs A和D与HSA之间的作用力是氢键和范德华力,分子对接结果与其一致.根据F9rster非辐射能量转移理论(FRET)分析了HSA和PDs之间的结合距离(r),其结果均小于4 nm,符合能量转移理论.进一步利用同步荧光、三维荧光和圆二色光谱考察了PDs与HSA结合过程中HSA空间构象的变化,结果显示,仅PDs A和C对HSA的芳香族氨基酸周围的疏水性略有增强作用.体外实验结果表明,HSA可以作为优良的载体来运输和储存PDs A~E,这为嘧啶衍生物的后续研究提供了可参考的实验数据. 相似文献