Chengjun Julian Chen

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An ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method employing electrospray ionization (ESI) has been developed for the determination of mangiferin in rat plasma using diphenhydramine as the internal standard (IS). Liquid-liquid extraction (LLE) was used for sample preparation and the analysis was achieved with gradient(More)
Lyophilization is a promising approach to ensure the long-term stability of liposomes. After decades of studies in this field, different lyoprotective mechanisms, such as water replacement and vitrification models, have been proposed. Much progress has been made in developing highly stable liposomes after lyophilization based on optimization of formulation(More)
Advanced glycation end products (AGEs) are major inflammatory mediators in diabetes, affecting atherosclerosis progression via macrophages. Metformin slows diabetic atherosclerosis progression through mechanisms that remain to be fully elucidated. The present study of murine bone marrow derived macrophages showed that (1) AGEs enhanced proinflammatory(More)
Experimental results are presented on physiological pulsatile flow past caged ball and tilting disc aortic valve prostheses mounted in an axisymmetric chamber incorporated in a mock circulatory system. The measurements of velocity profiles and turbulent normal stresses during several times in a cardiac cycle were obtained using laser-Doppler anemometry. Our(More)
Theoretically, if blood is to have directional flow and different magnitudes of velocity, pressure should be distributed in the left ventricle (LV) as a function of both space and time. Thus, regional pressure differences (RPD) were examined in the LV of 20 open-chested dogs. High-fidelity transducers were implanted through stab wounds at three positions in(More)
Pulsatile flow development past tissue valve prostheses in a model human aorta has been studied using qualitative flow visualization and quantitative laser-Doppler techniques. Experiments were conducted both in steady and physiological pulsatile flow situations and the measurements included the pressure drop across the valve, the instantaneous flow rate as(More)
A hydrophobic restorative composite based on a fluorocarbon analog of an alkyl methacrylate and a bisphenol adduct was formulated into a one-paste system, which polymerized in the presence of blue light. Physical, mechanical and water-related properties were determined. High contact angles and low water sorption were shown by the experimental composite.(More)
Pulsatile flow development past a caged ball valve in a model human aorta was studied using laser Doppler anemometry. Velocity profiles measured in the ascending aorta and in the mid-arch region were strongly influenced by the geometry of the valve at the root of the aorta. Velocity profiles distal to the valve were asymmetric with jet-like flow in the(More)
To investigate the stability of cytarabine-encapsulated multivesicular liposomes (MVLs) following freeze-thawing/freeze-drying, three types of phospholipids (EPC, DPPC, and DOPC) were separately employed to prepare MVLs using a double emulsification method. The cytarabine retention (CR), phase transition behavior, aggregation/rupture of vesicles and(More)
The effect of valve orientation on flow development in a model human aorta was studied by means of a qualitative flow visualization technique. The model replicated the geometry of the human aorta and the experiment simulated a physiologically realistic pulsatile flow. The following valves were studied: Starr-Edwards Stellite, Starr-Edwards silicone,(More)