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991.
High-performance liquid chromatography with tandem mass spectrometry has been used for rapid, specific, and sensitive analysis of busulfan in human plasma. Busulfan-d8 was used as internal standard. Analysis was performed on a C18 column (50 mm × 2.1 mm, 3.5-µm particles) with water–methanol 80:20 (v/v) as mobile phase at a flow-rate of 0.30 mL min?1. Detection was by tandem triple–quadrupole mass spectrometry with turbo ion-spray ionization. Linear calibration plots were obtained over the concentration range 1.096–1,096 ng mL?1. The assay is ideally suited to monitoring of busulfan and determination of its pharmacokinetic data. 相似文献
992.
Małgorzata Olejnik Teresa Szprengier-JuszkiewiczPiotr Jedziniak 《Journal of chromatography. A》2009,1216(46):8141-8148
The confirmatory LC-MS/MS method for the determination of residues for twelve coccidiostats including ionophore antibiotics (lasalocid, maduramycin, monensin, narasin, salinomycin, semduramycin) and chemical coccidiostats (clazuril, decoquinate, diclazuril, halofuginone, nicarbazin and robenidine) in poultry liver has been developed. The sample preparation was based on extraction with acetonitrile, defatting with Alumina columns and clean-up on Oasis HLB spe. The separation of analytes was performed on PhenylHexyl column with a gradient of acetonitrile, methanol and the ammonium formate pH 4.0. For all analytes, at least 2 diagnostic fragmentation ions were monitored. The validation, performed according to the CD 2002/657/EC, proved the suitability of the method for the confirmatory analysis of the coccidiostats. For lasalocid, however, low reproducibility was observed and the proper quantification could not be performed with this method. 相似文献
993.
Ma del Carmen Fernández-Fernández Alejandro Macías Laura Valencia 《Journal of organometallic chemistry》2009,694(22):3608-3613
The coordination capability of the new tetrapyridyl pendant-armed azamacrocyclic ligand L, towards Co(II), Ni(II), Cu(II) and Cd(II) ions was studied. The ligand and the complexes were characterized by microanalysis, LSI mass spectrometry, IR, UV-Vis and NMR spectroscopy, magnetic studies and conductivity measurements. Crystal structures of [Co2L(CH3CN)2](ClO4)4·2CH3CN and [Cd2L(NO3)2](NO3)2·2H2O complexes have been determined. The X-ray studies show the presence of dinuclear endomacrocyclic complexes with the metal ion in a similar distorted octahedral environment, coordinated by one pyridyl bridgehead group, two amine nitrogen atoms and two pyridyl pendant-arms. The sixth coordination position around the metal ion is completed by one acetonitrile molecule in [Co2L(CH3CN)2](ClO4)4·2CH3CN and by one monodentate nitrate anion in [Cd2L(NO3)2](NO3)2·2H2O. Different sort of intramolecular non-classical hydrogen bonds were found in the crystal lattice of both structures. 相似文献
994.
Hao-Xiang Zhong Ying-Li Ma Xue-Tai Chen Zi-Ling Xue 《Journal of solid state chemistry》2009,182(7):1679-2917
A simple hydrothermal reaction between Ba(NO3)2 and K2SiF6 results in the formation of 1D rod-like BaSiF6. The BaSiF6 rods can act as efficient precursors for production of tubular SiO2 by hydrothermal reaction in alkaline solutions. Powder X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), transmission electron microscopy (TEM), high resolution electron microscopy (HRTEM), and field emission scanning electron microscopy (FESEM) were used to characterize the phase and morphology of the final product. The experiments indicated the amount of NaOH, reaction temperature, and reaction time played important roles in the transformation process. A possible growth mechanism of tubular silica was proposed. 相似文献
995.
Zhongliang Wang Ying Ma Ruili Zhang Da Xu Hongbing Fu 《Journal of solid state chemistry》2009,182(4):983-86
A layered phosphovanadomolybdate/1,10-decanediamine (1,10-DAD) self-assembled ultrathin film was fabricated by means of alternating adsorption of mixed-addenda polyoxometalates (POMs) (phosphovanadomolybdate, H5[PMo10V2O40]) and 1,10-DAD, and its photochromic properties were investigated. It is found that the self-assembled multilayer (SAM) film shows high-photochromic response, excellent photochromic stability and reversibility. The photochromic behavior of the SAM is closely related to the reduction potentials of addenda atoms in mixed-addenda POMs. In the case of photo-reduced mixed-addenda POMs, the electron is localized on the more reducible atom, and the addenda atoms with higher reduction potentials show prior photochromism compared with those with lower reduction potentials. The coloration speed is improved after introduction of V into molybdenum POM. The well-ordered lamellar structure of the film was well maintained during the coloration. 相似文献
996.
Gelsor Norsang LiWei Ma Arne Dahlback Ciren Zhuoma Wangmo Tsoja Alina Porojnicu Zoya Lagunova Johan Moan 《Photochemistry and photobiology》2009,85(4):1028-1031
UVB from the sun and intake from food are the only human sources of vitamin D. Tibet is a unique region for comparisons of these sources: (1) it lies at a low latitude and at a high altitude and has very large annual fluences of UVB; (2) the traditional Tibetan food is poor in vitamin D. Blood samples were taken from 63 persons of different age, with different occupations and staying at different places. UVB doses at these places were measured. The samples were analyzed by a standard radioimmune assay for determination of the serum concentration of 25 hydroxyvitamin D (25(OH)D). The main finding was that among nomads, there seems to be severe vitamin D deficiency (serum levels of 25(OH)D < 30 n m ). We tentatively propose that the low level of 25(OH)D of nomads is related to their clothing and sun exposure habits. For persons of other occupations (students, teachers and farmers) the levels are higher, although a significant fraction of these persons also have lower levels than 75 n m , by many regarded as a limit for insufficiency related to a number of negative health conditions. The annual dose of vitamin D-generating UVB is about five times larger in Lhasa than in Oslo. Despite this, the average vitamin D status seems to be similar, except in the case of nomads. This phenomenon is certainly related to food habits. In conclusion, the 25(OH)D status among nomads in Tibet appears to be alarmingly low. However, for people of other occupations the status is more normal. 相似文献
997.
The process of ultrasound-assisted emulsification-microextraction (USAEME) was successfully applied for the first time for the extraction and pre-concentration of trace cadmium from water samples, followed by flame atomic absorption spectrometry (FAAS). In the proposed approach, sodium diethyldithiocarbamate trihydrate solution (NaDDTC·3H2O) was used as a chelating agent and carbon tetrachloride was selected as extraction solvent. Some effective parameters on the microextraction and the complex formation were selected and optimized. These parameters included extraction solvent type as well as extraction volume, time, temperature, and pH, the amount of the chelating agent, and salt effect. Under optimum conditions, an enrichment factor of 95 was obtained from only 5.0 mL of water sample. The calibration graph was linear in the range of 10-600 μg L−1 with a detection limit of 0.91 μg L−1. The relative standard deviation (R.S.D) for ten replicate measurements of 50 and 500 μg L−1 of cadmium were 2.56 and 1.62%. This proposed method was successfully applied in the analysis of four real environmental water samples and good spiked recoveries over the range of 96.5-101.7% were obtained. 相似文献
998.
Yuelong Ma 《Tetrahedron letters》2009,50(30):4343-4345
A concise synthesis of indolic enamides coscinamide A, coscinamide B, and the brominated tryptamine derivative igzamide is described. Both E- and Z-isomers of these natural compounds were obtained during the thermally assisted dehydration reaction and were tested for antitumor activity. Coscinamide B was found to possess antitumor activity against DU145 with an IC50 of 7.6 μg/mL. 相似文献
999.
Yanlei Ma Jiayuan Peng Long Huang Weijie Liu Peng Zhang Huanlong Qin 《Electrophoresis》2009,30(15):2591-2599
Identification of specific protein markers for colorectal cancer (CRC) could provide a basis for its early diagnosis and detection, as well as clues to the molecular mechanisms governing cancer progression. In the present study, 2‐D DIGE coupled with MS was used to screen for biomarker candidates in the serum proteome of ten human CRC samples and ten healthy control samples. After pooling identical amounts of serum proteins (based on total protein concentration), albumin/IgG was depleted under partially denaturing conditions. Subsequently, the serum samples were labeled with three different CyDyes, and separated by 2‐D DIGE. After analysis with the biological variation analysis module of the DeCyder software, only three spots were found to be significantly elevated in all patient groups (with ratios from 1.52 to 9.08), whereas five spots were significantly down‐regulated in patients (with ratios from ?1.23 to ?10.21) (t‐test; p<0.05). Finally, two potential biomarkers, Transaldolase 1 and thyroid receptor interactor, were chosen for validation and analysis by ELISA with the serum of 30 CRC patients and 30 healthy controls. The serum levels of the two proteins correlated well with the 2‐D DIGE results. Thus, 2‐D DIGE approaches show great promise for biomarker discovery in CRC. 相似文献
1000.
Densities have been measured by an oscillating-tube densimeter for aqueous solutions of glycylglycine and glycylglycylglycine
in aqueous xylitol solutions with xylitol mass fractions ranging from 0 to 0.15 at 298.15 K. Apparent molar volumes and limiting
partial molar volumes have been used to calculate the corresponding transfer volumes from water to different concentrations
of xylitol + water mixtures. The results are interpreted in terms of the cosphere overlap model. 相似文献