Role of a Novel Pyridostigmine Bromide-Phospholipid Nanocomplex in Improving Oral Bioavailability

Qun-you Tan,Jing-qing Zhang,Ni-ni Hu,Guo-dong Liu,Hua-feng Yin,Li Zhang,Hong Wang,Lu-yang Lu 대한약학회 2012 Archives of Pharmacal Research Vol.35 No.3

A novel pyridostigmine bromide (PB)-phospholipid nanocomplex (PBPLC) was prepared to increase the bioavailability of PB. A central composite design approach was employed for process optimization. The physicochemical properties of PBPLC were investigated by means of differential scanning calorimetry, ultraviolet spectroscopy, Fourier transformed infrared spectroscopy and the n-octano/water partition coefficient. The intestinal permeability of PBPLC was observed via a single pass intestinal perfusion in rats. After oral administration of PBPLC, the concentrations of PB at predetermined time points were determined by HPLC, and the pharmacokinetic parameters were computed by DAS 2.1.1 software. Multiple linear regression analysis for process optimization revealed that the optimal PBPLC was obtained when the values of X1, X2, and X3 were 8, 40oC, and 4 mg/mL, respectively. The average particle size and zeta potential of PBPLC with the optimized formulation were 204.60 nm and −25.12 mV, respectively. Non-covalent interactions between PB and phospholipids were found in the PBPLC. The n-octanol/water partition coefficient of PBPLC was substantially increased. PBPLC had better intestinal permeability in comparison with free PB. Mean plasma drug concentration-time curves of PBPLC and free PB after oral administration were both in accordance with the two-compartment open model. The values of pharmacokinetic parameters of PBPLC and free PB were the peak time (Tmax) 2 h vs 2 h, the maximum concentration (Cmax) 22.79 μg/mL vs 6.00 μg/mL, and the value of the area under the concentration vs time curve (AUC0-∞) 7128.21 μg·min/mL vs 1772.36 μg·min/mL, respectively. In conclusion, compared with free PB, PBPLC remarkably improves the oral bioavailability of PB, which is likely due to its higher lipophilicity and permeability.

TRANSIENT DYNAMIC CHARACTERISTICS OF A NON-PNEUMATIC MECHANICAL ELASTIC WHEEL ROLLING OVER A DITCH

You-Qun Zhao,Yao-Ji Deng,Fen Lin,Ming-Min Zhu,Zhen Xiao 한국자동차공학회 2018 International journal of automotive technology Vol.19 No.3

The transient dynamic characteristic of a tire, which has a significant effect on vehicle handling stability and ride comfort, is difficult to study in detail because of its highly non-linear behavior. In this study, the transient dynamic characteristics of a non-pneumatic wheel, called the mechanical elastic wheel (MEW), which was rolling over a ditch were investigated by the explicit dynamic finite element (FE) method. A three-dimensional FE model of MEW considering geometric nonlinearity, material nonlinearity and large contact deformation between the wheel and the road, was established. For the validation of the accuracy and reliability of the FE model of MEW, the simulation and the experimental results of the radial stiffness and footprint of MEW were compared and analyzed. A dynamic simulation of the validated FE model of MEW rolling over a ditch was conducted using the ABAQUS/Explicit program. The equivalent stress and the contact stress generated during the process of the rolling MEW impacting the ditch were studied in detail. The effect of the rolling speed on the transient dynamic characteristics was also analyzed based on the simulation results. The simulation results could provide guidance for the optimization of the MEW structure and vehicle dynamics.

ACTIVE LQR MULTI-AXLE-STEERING METHOD FOR IMPROVING MANEUVERABILITY AND STABILITY OF MULTI-TRAILER ARTICULATED HEAVY VEHICLES

You-Qun Zhao,Zhao Wen Deng,Qi Xian Zhao,Bao Hua Wang,Wei Gao,Xin Xin Kong 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.4

Directional performance and highway stability are two important aspects that need to be considered in development and design of a heavy articulated vehicles. To improve the maneuverability and stability of a multi-trailer articulated heavy vehicle (MTAHV), an active linear quadratic regulator (LQR) multi-axle-steering method is designed and examined. First, a linear yaw-plane model with four-degree-of freedom (4-DOF) for MTAHV is built and validated. Thus, a reference model supplying the desired state responses is introduced. Then, an active control algorithm of multi-axle-steering for the rear axles of tractor and full-trailer is investigated, and a LQR controller is proposed based on the linear vehicle model to make the control variables track the desired state responses. The control strategy concentrates on keeping the actual yaw rate and side-slip angle follow the steady-state yaw rate and zero side-slip angle. Finally, the effectiveness of the designed approach on enhancing the maneuverability and stability of the MTAHV have been validated through the simulations of the low-speed 360o roundabout and the single lane-change maneuver with high speed, respectively. The method has a certain reference value for improving the active safety of the MTAHV.

DFT Analysis of the Adsorption of Methyl Nitrate on Al2O3 Surfaces

Yan-qun Wang,Xiu-fen Yan,Wei Xiao,You-xiang Shao 대한화학회 2017 Bulletin of the Korean Chemical Society Vol.38 No.6

The adsorption of the energetic molecule methyl nitrate (CH3ONO2) on α-Al2O3(0001) and γ-Al2O3(110) surfaces was investigated using first-principles calculations based on density functional theory and the generalized gradient approximation. We found that CH3ONO2 approaches the two surfaces by either the oxygen connected with carbon atom or an oxygen atom of the nitro group; however, the former interaction is more stable. If CH3ONO2 approaches the surface through the oxygen atom of the nitro group, the adsorption is non-dissociative; while it is nearly dissociative if CH3ONO2 adsorbs on the surface via the oxygen connected with carbon atom and a surface tri-coordinated Al atom. Moreover, the dissociation trend on the γ-Al2O3(110) surface is more pronounced. In addition, the adsorption of CH3ONO2 on the γ-Al2O3(110) surface is more favorable. Finally, although strong interactions exist between CH3ONO2 and the surfaces, the structures of the alumina films are not affected by the adsorption of CH3ONO2.

An improved interval analysis method for uncertain structures

Jie Wu,You Qun Zhao,Su Huan Chen 국제구조공학회 2005 Structural Engineering and Mechanics, An Int'l Jou Vol.20 No.6

An improved interval analysis method for uncertain structures

Wu, Jie,Zhao, You Qun,Chen, Su Huan Techno-Press 2005 Structural Engineering and Mechanics, An Int'l Jou Vol.20 No.6

Based on the improved first order Taylor interval expansion, a new interval analysis method for the static or dynamic response of the structures with interval parameters is presented. In the improved first order Taylor interval expansion, the first order derivative terms of the function are also considered to be intervals. Combining the improved first order Taylor series expansion and the interval extension of function, the new interval analysis method is derived. The present method is implemented for a continuous beam and a frame structure. The numerical results show that the method is more accurate than the one based on the conventional first order Taylor expansion.

RAMS evaluation for a steel-truss arch high-speed railway bridge based on SHM system

Zhao, Han-Wei,Ding, You-Liang,Geng, Fang-Fang,Li, Ai-Qun Techno-Press 2018 Structural monitoring and maintenance Vol.5 No.1

The evaluation theory of reliability, availability, maintainability and safety (RAMS) as a mature theory of state evaluation in the railway engineering, can be well used to the evaluation, management, and maintenance of complicated structure like the long-span bridge structures on the high-speed railway. Taking a typical steel-truss arch bridge on the Beijing-Shanghai high-speed railway, the Nanjing Dashengguan Yangtze River Bridge, this paper developed a new method of state evaluation for the existing steel-truss arch high-speed railway bridge. The evaluation framework of serving state for the bridge structure is presented based on the RAMS theory. According to the failure-risk, safety/availability, maintenance of bridge members, the state evaluation method of each monitoring item is presented. The weights of the performance items and the monitoring items in all evaluation levels are obtained using the analytic hierarchy process. Finally, the comprehensive serving state of bridge structure is hierarchical evaluated.

Cloning and characterization of the cardiac-specific Lrrc10 promoter

( Xiong Wei Fan ),( Qing Yang ),( You Liang Wang ),( Yan Zhang ),( Jian Wang ),( Jia Jia Yuan ),( Yong Qing Li ),( Yue Qun Wang ),( Yun Deng ),( Wu Zhou Yuan ),( Xiao Yang Mo ),( Yong Qi Wan ),( Karen 생화학분자생물학회(구 한국생화학분자생물학회) 2011 BMB Reports Vol.44 No.2

Leucine-rich repeat containing protein 10 (LRRC10) is characterized as a cardiac-specific gene, suggesting a role in heart development and disease. A severe cardiac morphogenic defect in zebrafish morphants was recently reported but a contradictory result was found in mice, suggesting a more complicated molecular mechanism exists during mouse embryonic development. To elucidate how LRRC10 is regulated, we analyzed the 5`enhancer region approximately 3 kilo bases (kb) upstream of the Lrrc10 start site using luciferase reporter gene assays. Our characterization of the Lrrc10 promoter indicates it possesses complicated cis-and trans-acting elements. We show that GATA4 and MEF2C could both increase transcriptional activity of Lrrc10 promoter individually but that they do not act synergistically, suggesting that there exists a more complex regulation pattern. Surprisingly, knockout of Gata4 and Mef2c binding sites in the 5`enhancer region (-2,894/-2,889) didn`t change the transcriptional activity of the Lrrc10 promoter and the likely GATA4 binding site identified was located in a region only 100 base pair (bp) upstream of the promoter. Our data provides insight into the molecular regulation of Lrrc10 expression, which probably also contributes to its tissue-specific expression. [BMB reports 2011; 44(2): 123-128]