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991.
Plasma free metanephrines (PFMs) have high sensitivity for detecting pheochromocytoma (PCC). Herein, we developed a simple and reliable liquid chromatography tandem mass spectrometry assay for PFMs determination in Chinese population. PFMs were enriched by SPE without requiring extract evaporation or the use of buffers containing nonvolatile salts. The analytes were analyzed in multiple reaction monitoring mode. Inter‐ and intra‐assay precisions were ≤4.3% and ≤ 6.3%. The lower limits of quantification were 0.07 nmol/L for metanephrine and 0.06 nmol/L for normetanephrine. Recoveries of PFMs were in the range of 89.3–113%. The method was free from significant matrix effect, carryover and interference. Owing to its fast analysis time, more than 150 samples/day could be easily performed by a single operator. With the established reference intervals of PFMs in the Chinese population, this simple and robust LC–MS/MS method could be valuable for use in routine clinical laboratories. It is noted that the combined tests of PFMs with urinary catecholamines or urinary vanillylmandelic acid could improve specificity. 相似文献
992.
Houfu Lv Tianfu Liu Xiaomin Zhang Yuefeng Song Hiroaki Matsumoto Na Ta Chaobin Zeng Guoxiong Wang Xinhe Bao 《Angewandte Chemie (International ed. in English)》2020,59(37):15968-15973
In situ exsolution of metal nanoparticles in perovskite under reducing atmosphere is employed to generate a highly active metal–oxide interface for CO2 electrolysis in a solid oxide electrolysis cell. Atomic‐scale insight is provided into the exsolution of CoFe alloy nanoparticles in La0.4Sr0.6Co0.2Fe0.7Mo0.1O3?δ (LSCFM) by in situ scanning transmission electron microscopy (STEM) with energy‐dispersive X‐ray spectroscopy and DFT calculations. The doped Mo atoms occupy B sites of LSCFM, which increases the segregation energy of Co and Fe ions at B sites and improves the structural stability of LSCFM under a reducing atmosphere. In situ STEM measurements visualized sequential exsolution of Co and Fe ions, formation of CoFe alloy nanoparticles, and reversible exsolution and dissolution of CoFe alloy nanoparticles in LSCFM. The metal–oxide interface improves CO2 adsorption and activation, showing a higher CO2 electrolysis performance than the LSCFM counterparts. 相似文献
993.
Qian Guan Yong Liu Bo Ling Guisheng Zeng Haiyan Ji Jiefei Zhang Qiang Zhang 《国际化学动力学杂志》2020,52(7):463-471
Sodium arsenate, the main component of arsenic-containing solid waste pollutants, causes serious environmental health threats. Crystallization is one of the effective methods for separating and purifying sodium arsenate from arsenic-alkali residue lixivium. However, the crystallization process is limited for its low observability and the lack of separation and purification data. In this work, a laser detection system with a magnetic field generator was designed, and the solubility, metastable zone width, interfacial tension, interfacial entropy factor, crystal nucleation, and growth rate of sodium arsenate were investigated in a constant composition environment. The results showed that the solubility, metastable zone width, interfacial tension, and interfacial entropy factor decreases with the presence of a magnetic field. The magnetic field shortened the crystallization induction time and changed the nucleation and growth rate of sodium arsenate. Under the magnetic field, the nucleation rate increased from 2.43 × 1016 to 8.98 × 1017 (s m3)−1, and the growth rate decreased from 4.94 × 10−8 to 2.73 × 10−8 (s m3)−1, the growth mechanism of sodium arsenate as a continuous growth mode was unchanged. In addition, the X-ray diffraction and infrared showed that the crystal structure of sodium arsenate is unaffected by the magnetic field, indicating that the enhancement of the crystallization process of sodium arsenate with the magnetic field could be a feasible method in engineering application. 相似文献
994.
J. J. Pan FengQing Zhou Kejian Guan Joy Jiang Liang Dong Albert Li Xiangdong Qiu Jonathan Zhang 《光学学报》2003,23(Z1)
With rich products development experience in WDM telecommunication networks, we introduce a few of high channel count, multiplexed FBG fiber optic sensor systems featured in reliable high performance and low cost. 相似文献
995.
J.J. Pan Wei Wang Xiangdong Qiu Mingjie Zhang Kejian Guan Joy Jiang Jonathan Zhang 《光学学报》2003,23(Z1)
A novel optical transient suppression technique to dramatically reduce gain variation of EDFA with un-cooled pump is demonstrated experimentally, showing excellent performance of 50μs transient time with no more than 0.5dB excursion and 0.25dB offset. 相似文献
996.
Xiaomin Bei Changsheng Shi Zhongzhu Liu 《International Journal of Theoretical Physics》2004,43(6):1555-1560
The Proca effect of an electric field is studied in curved space. A Kerr–Newman metric with the photon rest mass can be presented by the analytic continuation (Xu, C. M. (....). General Relativity and Modern Cosmology, Nanking Normal University) in a short range. It yields the correction in the Kerr–Newman space. 相似文献
997.
Y. Guan P. C. Lloyd P. M. Evans R. B. Kemp 《Journal of Thermal Analysis and Calorimetry》1997,49(2):785-794
Microcalorimeters to monitor the heat dissipation of bench-scale animal cell cultures on line and in real time require a continuous circuit between the vessel measuring heat flow rate and the bioreactor. The modifications to the transmission lines and calorimetric heat exchanger were to: (i) reverse the usual upward direction of the cell suspension in the flow vessel to downwards; (ii) install an in situ washing/cleaning facility; (iii) use low diffusivity PEEK material; and (iv) maintain thermal equilibration by water-jacketing the transmission tubing. Chemical calibration showed that there was more than a 20% difference between the physical volume and the effective thermal volume. An appropriate thermodynamic system was defined in order to permit enthalpy balance studies.We are indebted to the BBSR.C (UK) for financial support under grant No. 2/3680. Mr. R.L. Taylor (ThermoMetric Ltd, Northwich, Cheshire) has been extremely helpful in discussions about the various designs. 相似文献
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