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162.
Several products marketed as natural drugs for enhancement of anti-diabetic function have been analyzed and found to contain synthetic hypoglycemic drugs. In the work discussed in this paper, LC-MS analysis ten such drugs [gliquidone (GLQ), glipizide (GLZ), gliclazide (GLC), glibenclamide (GLB), glimepiride (GLM), rosiglitazone (RGL), repaglinide (RPG), metformin (DMBG), phenformin (DBI), and tolbutamide (TOL)] has been improved. Quantification was by use of multiple reaction monitoring mode. The intra-day and inter-day precision of the method ranged from 2.13 to 5.55% and from 3.78 to 8.14%, respectively. LOQ was 1, 1, 1.2, 2, 3, 3, 5, 5, 2, and 1 μg L?1 for GLQ, GLZ, GLC, GLB, GLM, RGL, RPG, DMBG, DBI, and TOL, respectively. The structures of the compounds were identified by collision-induced dissociation mass spectral analysis. The results showed that a variety of synthetic drugs had been illegally added to anti-diabetic herbal products. A surprising result was that some of the adulterants were added into the capsule shell instead of capsule contents. LC-MS–MS is a powerful tool, and the method has wide applicability. 相似文献
163.
Fafu Yang Ziyu Jiao Zhisheng Huang Jianwei Xie Hongyu Guo 《Journal of inclusion phenomena and macrocyclic chemistry》2012,74(1-4):257-263
By formylation of calix[4]-1,3-aza-crown in hexamethylenetetramine/trifluoroacetic acid system, the first formylated calix[4]-aza-crown derivative 6 was synthesized in yield of 61%. Reacting compound 6 with salicyloyl hydrazine, 2,4-dinitrophenyl hydrazine, nicotinyl hydrazine or phenyl thiosemicarbazide afforded four novel calix[4]crown hydrazone derivatives 7a–d in yields of 70–90%. By condensating compound 6 with series of bifunctional reagents, the novel mono-bridged biscalix[4]-aza-crown hydrazone derivatives 8a–c were prepared in high yields. The extraction experiments showed that all new compounds were good receptors for metal cations, especially, for soft metal cations. The extraction results suggested that the hydrazone groups produced favorable influences for binding soft cations. The two calix[4]arene units in compounds 8a–c could bind metal cations concurrently. 相似文献
164.
165.
Shuyuan Gan Zhisheng Zhang Yifan Zhou Jinfei Shi 《Applied Mathematical Modelling》2013,37(20-21):8785-8795
In this paper, a production system consisting of two serial machines and an intermediate buffer is studied. A shortage cost is incurred when the upstream machine is down and the buffer is exhausted. The practical example for this type of system can be an automated work center or an automobile general assembly.Researches on a similar two-machine system have been done in some articles where maintenance and an intermediate buffer are considered, but the spare parts are not involved. Nevertheless, spare parts are essential for maintenance implementation, and there is interaction between the buffer inventory and the spare parts due to maintenance activity. This paper is aimed to investigate three types of cost related to the intermediate buffer inventory, and obtain their expectations as functions of several decision parameters on maintenance, buffer, and spare parts during a renewal cycle, by using mathematical analysis. The proposed method can be an important basis for further study of system cost calculation and decision making optimization. 相似文献
166.
Transient response of a dual clutch transmission (DCT) powertrain to synchroniser mechanism engagements is investigated using a lumped inertia model of the powertrain. Original research integrates lumped inertia powertrain models for the DCT with a detailed synchroniser mechanism model and two separate engine models, comprising of a mean torque model and a harmonic torque model, using torque derived from piston firing. Simulations are used to investigate the synchroniser mechanism engagement process in a previously unscrutinised operating environment. Simulations are performed using both engine torque models, with the mean torque model demonstrates the highly nonlinear nature of synchroniser mechanism engagement, and the powertrain response to the engagement process. Through the introduction of harmonic engine torques, additional excitation is present in the mechanism during engagement, and increased vibration of the synchroniser sleeve results. The impact of vibrations is particularly important to the increased wear of indexing chamfer contact surfaces. 相似文献
167.
By applying the theory of quasiconformal maps in measure metric spaces that was introduced by Heinonen-Koskela, we characterize
bi-Lipschitz maps by modulus inequalities of rings and maximal, minimal derivatives in Q-regular Loewner spaces. Meanwhile the sufficient and necessary conditions for quasiconformal maps to become bi-Lipschitz
maps are also obtained. These results generalize Rohde’s theorem in ℝ
n
and improve Balogh’s corresponding results in Carnot groups.
This research is supported by China NSF (Grant No. 10271077) 相似文献
168.
Application of Nanogold Probe Coupled with Silver Enhancement in Rapid cTnI Colorimetric Immunoassay
Nong Yue HE Hui Shi GUO Di YANG Chun Rong GU Zhi Ping BIAN Wen Hui WAN Ji Nan ZHANG State Key Laboratory of Bioelectronics Southeast University Nanjing Institute of Cardiovascular Disease First Affiliated Hospital of Nanjing Medical University Nanjing 《中国化学快报》2005,(12)
Cardiac troponin I (cTnI) in the serum of patients has been established as a principal biochemical marker of myocardial damage1-4. Fast detection of cTnI will be helpful for the diagnosis of acute myocardial infarction (AMI), the identification of myocardial injury (MI) and the stratification of cardiac risk. A number of serological tests have been developed for the detection of cTnI. As known, among many methods, enzyme-linked immunosorbent assay (ELISA) and radioimmunoassay (RIA) wer… 相似文献
169.
XiaoXiaGE RuoNongFU RongJiDAI LiWenLIU MeiLingQI 《中国化学快报》2004,15(4):428-430
Heptakis(2,3,6-tri-O-octyl)-β-cyclodextrin was coated onto the fused silica capillary by sol-gel technology.Column efficiency and column selectivity were studied.The results indicated that high ability of separation was acquired.Positional isomers of aromatic compounds were well separated. 相似文献
170.
Zhisheng Lin Rongyo Chang Haitau Lin Chuhua Pan Yuliang Long 《International Journal of Infrared and Millimeter Waves》1998,19(3):569-584
An automatic slotted line system controlled with the micro-computer IBM 80486 which we have developed had been reported. In this paper, the measuring principles and the software designs of impedance, attenuation, phase shift and detection law of diode measurement to make use of this system will be described, some typical measurement results will be given. This method is adaptable for MM-Wave band and other Micro-wave band. 相似文献