PubMed | University of Auckland, Zheng Zhou University and Nanjing University of Technology
Type: | Journal: Journal of chromatography. B, Analytical technologies in the biomedical and life sciences | Year: 2015
To enable an investigation of pharmacokinetics and tissue distribution of Aucubin, Ajugol and Catalpol in rats, a high-performance liquid chromatography-electro spray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) method was developed for the simultaneous quantitative determination of the three compounds. Biological samples were prepared by a simple protein precipitation with methanol (containing 0.05% formic acid). The analytes were separated by a C18 reversed phase column and detected with a triple quadrupole tandem mass spectrometer in the multiple-reaction monitoring (MRM) mode to monitor the precursor-to-product ion transitions of m/z 364.3149.0 for Aucubin, m/z 366.5151.1 for Ajugol, m/z 380.0183.3 for Catalpol and m/z 530.3183.1 for Picroside-II (IS) in positive ionization. Good linearity of each calibration curve was produced over the concentration range of 1-1000ng/mL. The lower limit of quantification (LLOQ) was 1ng/mL for the three analytes. This method was successfully applied to the pharmacokinetic and tissue distribution studies of Aucubin, Ajugol and Catalpol in rat. The current results revealed pharmacokinetic behaviors of the herb compound and provided novel evidence of the presence of Aucubin and Catalpol in rat brain. The acquired data would be helpful for the clinical application and further studies of Traditional Chinese Medicines (TCM) with active ingredients of Iridoid Glycosides.
Wang K.-F.,Zheng Zhou University |
Zhang Z.-H.,Zheng Zhou University
2010 International Conference on Future Information Technology and Management Engineering, FITME 2010 | Year: 2010
This paper introduces the design and implementation of a safe Public Key Infrastructure based on Transport Layer Security. Through the establishment of safe connection between each part of the PKI system, it can effectively resist the attack from the internal department. But the use of safe connection increases burden to inquiring certificate. To improve the efficiency of the certificate inquiring, we use OpenLdap server as the certificate distribution system in the premise of not reducing safety performance. © 2010 IEEE.
Li T.,Zheng Zhou University |
Zhang Z.,Zheng Zhou University
Proceedings - 2010 International Conference on Intelligent System Design and Engineering Application, ISDEA 2010 | Year: 2011
This the paper discusses the seismic reliability analysis of electric power system. In the paper, through the analysis of properties of the power system and power network system characteristics, some suggestions are put forward that it is not only need to consider site selection, power substations buildings, power structure analysis in individually in the seismic reliability analysis of power system, but to guarantee the reliability of the power system. Therefore it is necessary to ensure the connecting reliability from the plants to the users (substations). Based on this, it can be done the electric power system the seismic design, maintenance and modification. For a power network system, the seismic reliability has been analyzed in this paper, and the practical conclusions were obtained. © 2010 IEEE.
Cheng Z.,Zheng Zhou University |
Jiao L.,Zheng Zhou University
Lecture Notes in Electrical Engineering | Year: 2012
Based on the brief introduction of the port-controlled Hamiltonian (PCH) system, the PCH system model of non-salient permanent magnet linear synchronous motor is established. The control laws are presented in load known conditions. Simulation results show that the method of port-controlled Hamiltonian is easy to be realized to control permanent magnet linear synchronous motor (PMLSM) and the physical meaning is clear and the effect is ideal. © 2012 Springer-Verlag London Limited.
Du G.-F.,Zheng zhou University |
Zhang Z.-H.,Zheng zhou University |
Wu X.-Y.,Zheng zhou University
Proceedings - 2010 2nd International Conference on Multimedia Information Networking and Security, MINES 2010 | Year: 2010
This paper introduces the design and implementation of HTTP proxy server based on real-time link. The real-time link packages UPLink and PSLink into a link. The UPLink is the link between user and proxy server, and PSLink is the link between proxy server, and target server. These two links exist and close together, and it can solve the problem of link's closed incompletion. This approach can reduce network congestion and improve the efficiency of proxy server. © 2010 IEEE.
Song B.,Zheng Zhou University |
Zhang Z.-H.,Zheng Zhou University
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2013
It is easy to be detected by X2 and RS steganalysis with high accuracy that using LSB algorithm to hide information in digital image. We started by selecting information embedded location and modifying the information embedded method, combined with sub-affine transformation and matrix coding method, improved the LSB algorithm and a new LSB algorithm was proposed. Experimental results show that the improved one can resist the X2 and RS steganalysis effectively. © 2013 SPIE.
Liu F.,Zheng Zhou University |
Zhu H.,Zheng Zhou University |
Gu Z.,Zheng Zhou University |
Liu Y.,Zheng Zhou University
Communications in Computer and Information Science | Year: 2011
Node localization and tracking is a highlight research in wireless sensor networks(WSN), and localization algorithm plays the most important role in improving the localization accuracy. To overcome the drawback of the low localization accuracy of conventional Least Squares(LS) with small number reference nodes, this paper proposes a linear algorithm based on received signal strength indicator (RSSI), which implements Taylor Series Expansion to linearize binary quadratic equations. With the same number reference nodes, simulation result shows, compared to conventional LS, the linear algorithm can highly enhance the localization accuracy. © 2011 Springer-Verlag.
Niu L.,Zheng Zhou University |
Zhou J.-J.,Zheng Zhou University
Kung Cheng Je Wu Li Hsueh Pao/Journal of Engineering Thermophysics | Year: 2015
Considering the conjugate heat transfer, we optimized the operating parameters of louver fin heat exchanger with the 3-D numerical analysis software. Finally we got the optimal operating parameters, with higher Nu number and lower f coefficient, which are the entrance velocity of 3.5 m/s, the inlet temperature of 303.12 K and the flat tube temperature of 336.14 K. At the point, the resistance factor f is 0.61353, Nu number is 46.46. Comparing with the original working condition, the resistance factor f reduces 17.73% and Nu number increases 31.05%. © 2015, Science Press. All right reserved.
Chen E.,Zheng Zhou University |
Chu C.,Zheng Zhou University
Eurasip Journal on Wireless Communications and Networking | Year: 2014
Single-carrier frequency domain equalization (SC-FDE) has been shown to be an attractive transmission scheme for broadband wireless channels. However, its performance would degrade a lot if the channel is fast time-varying. In this paper, we analyzed the single-carrier fractional Fourier domain equalization (SC-FrFDE) system and applied it to the fast timevarying channel. It can solve the time-varying problem by selecting the optimal fractional Fourier transform order. To this SC-FrFDE system, its transmitter uses chirp-periodic circular prefix to eliminate ISI and this has an evident disadvantage that the receiver need to feedback the optimal fractional Fourier transform order to the transmitter through a feedback channel. To simplify the system, we propose to use zero padding (ZP) at the transmitter. There is already the overlap-add method as ZP in SC-FDE system. But the overlap-add method cannot be used in fast time-varying channels. Thus, we propose a new method as ZP. Simulation results show that our proposed method can significantly improve the system performance. © 2014 Chen and Chu.
Zhang C.,Zheng Zhou University |
Wang D.,Zheng Zhou University |
Zhu Y.,Zheng Zhou University |
Han Y.,Zheng Zhou University |
And 2 more authors.
International Journal of Thermal Sciences | Year: 2015
Heat transfer and friction loss characteristics of a plain tube fitted with double spiral spring (DSS) are investigated by a three dimensional numerical simulation. The outer diameters of the DSS are 9 mm, 12 mm, 15 mm, and 18 mm, respectively. The simulation results indicate that the fluid in the tube inserted with DSS shows three-dimensional helical flow, and that the circumferential and the radial velocity of fluid near the tube wall are improved. At the same Reynolds number, the average radial and tangential velocities of the DSS tube are significantly higher than those of the plain tube. The Nusselt number increases and the friction factor decreases in tube with DSS insert as the Reynolds number increases. With the increase of the ds/D of DSS, the friction factor becomes higher. The field synergy principle (FSP) and entransy dissipation extremum principle (EDEP) analysis provide a reliable criterion for exploring the mechanism of heat transfer enhancement. The field synergy number of the tube inserted with DSS is much higher than that of plain tube, which indicates effective improvement of flow and heat transfer by inserted DSS. Meanwhile, the value of performance evaluation criterion (PEC) could be up to 1.5. © 2015 Elsevier Masson SAS.