AIM:To investigate whether the secretion of phospha-tidylcholine(PC)in intestinal mucus occurs by apical secretion or via basolateral excretion and to determine its subsequent passage across the tight junctions to the...AIM:To investigate whether the secretion of phospha-tidylcholine(PC)in intestinal mucus occurs by apical secretion or via basolateral excretion and to determine its subsequent passage across the tight junctions to the apical mucus.METHODS:We addressed this question using the po-larized intestinally differentiated tumor cell line CaCo-2 grown on filters to confluence in Transwell culture chambers.The released PC and sphingomyelin(Sph)from apical and basolateral media were analyzed by mass spectrometry.RESULTS:The secreted PC species were identical in both compartments indicating the same intracellular origin of PC.However,PC secretion into the basolateral compart-ment was more effective,and the PC:Sph ratio in the ba-solateral compartment was signif icantly higher than that in the apical compartment(8.18 ± 1.84 vs 4.31 ± 1.22,P = 0.01).Both pathways were temperature sensitive and were unaltered in the presence of cyclosporine.CONCLUSION:The data demonstrate the PC secre-tion capacity of CaCo-2 cells and indicate two sepa-rated apical and basolateral release mechanisms.展开更多
A novel MEMS device boning system is presented. Aiming at the high velocity, high precision and high flexibility requirements, a novel manipulator of planar parallel structure is developed to substitute ordinary X-Y t...A novel MEMS device boning system is presented. Aiming at the high velocity, high precision and high flexibility requirements, a novel manipulator of planar parallel structure is developed to substitute ordinary X-Y table. In addition, the machine vision is implemented to improve the system' s flexibility. The initial angular positions of the joints are estimated by the extended Kalman filter algorithm. As a resuh, the manipulator's absolute locating accuracy in its workspace is guaranteed indirectly. For any MEMS device, the bonding system itself can be used as measurement equipment to create the device' s geometry model, which is the base to do off-line programming. A quite ideal trade-off between the system' s flexibility and efficiency is got. Finally, some verified motion specification of the manipulator, the bonding experimental results and the verified qualities of the bonded devices are provided.展开更多
Programmable metasurface enables controlling electromagnetic (EM) waves in real time. By programming the states of active device embedded in metasurface element, the EM properties of the digital metasurface can be cha...Programmable metasurface enables controlling electromagnetic (EM) waves in real time. By programming the states of active device embedded in metasurface element, the EM properties of the digital metasurface can be changed quickly without redesigning their structures. However, large numbers of long-distance wires are required to connect the programmable metasurface to provide the coded signals from field programmable gate array (FPGA) when controlling the metasurface at a long distance, which is complicated and inconvenient. Here, we propose an infrared-controlled programmable metasurface that can be programmed remotely. The infrared transceiver is able to switch the coding sequences stored in the FPGA controller, thus controlling the voltage on the varactors integrated in the metasurface. Experiment is performed at microwave frequencies, and the measured results verify that the scattering beams of the metasurface sample can be changed remotely by using infrared ray. The proposed infrared-controlled programmable metasurface opens up avenues for constructing a new class of remotely-tuning dynamic metasurfaces.展开更多
We have investigated the transport properties of the Dirac fermions through a ferromagnetic barrier junction on the surface of a strong topologicM insulator. The current-voltage characteristic curve and the tunneling ...We have investigated the transport properties of the Dirac fermions through a ferromagnetic barrier junction on the surface of a strong topologicM insulator. The current-voltage characteristic curve and the tunneling conductance are calculated theoretically. Two interesting transport features are predicted: observable negative differential conductances and linear conductances tunable from unit to nearly zero. These features can be magnetically manipulated simply by changing the spacial orientation of the magnetization. Our results may contribute to the development of high-speed switching and functional applications or electricalIy controlled magnetization switching.展开更多
基金Supported by A Grant From the Dietmar Hopp Foundation (Stremmel WR)the Post-Doc programme of the Medical Faculty of the University of Heidelberg (Gotthardt D and Braun A)
文摘AIM:To investigate whether the secretion of phospha-tidylcholine(PC)in intestinal mucus occurs by apical secretion or via basolateral excretion and to determine its subsequent passage across the tight junctions to the apical mucus.METHODS:We addressed this question using the po-larized intestinally differentiated tumor cell line CaCo-2 grown on filters to confluence in Transwell culture chambers.The released PC and sphingomyelin(Sph)from apical and basolateral media were analyzed by mass spectrometry.RESULTS:The secreted PC species were identical in both compartments indicating the same intracellular origin of PC.However,PC secretion into the basolateral compart-ment was more effective,and the PC:Sph ratio in the ba-solateral compartment was signif icantly higher than that in the apical compartment(8.18 ± 1.84 vs 4.31 ± 1.22,P = 0.01).Both pathways were temperature sensitive and were unaltered in the presence of cyclosporine.CONCLUSION:The data demonstrate the PC secre-tion capacity of CaCo-2 cells and indicate two sepa-rated apical and basolateral release mechanisms.
基金Supported by the High Technology Research and Development Programme of China (No. 2003AA404060) and the National Natural Science Foundation of China (No.60405008).
文摘A novel MEMS device boning system is presented. Aiming at the high velocity, high precision and high flexibility requirements, a novel manipulator of planar parallel structure is developed to substitute ordinary X-Y table. In addition, the machine vision is implemented to improve the system' s flexibility. The initial angular positions of the joints are estimated by the extended Kalman filter algorithm. As a resuh, the manipulator's absolute locating accuracy in its workspace is guaranteed indirectly. For any MEMS device, the bonding system itself can be used as measurement equipment to create the device' s geometry model, which is the base to do off-line programming. A quite ideal trade-off between the system' s flexibility and efficiency is got. Finally, some verified motion specification of the manipulator, the bonding experimental results and the verified qualities of the bonded devices are provided.
基金This work was supported by the National Key Research and Development Program of China(2017YFA0700201,2017YFA0700203 and 2016YFC0800401)National Natural Science Foundation of China(61890544,61522106,61631007,61571117,61731010,61735010,61722106,61701107,and 61701108)+3 种基金Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX19_0081)Scientific Research Foundation of Graduate School of Southeast University(YBPY1938)Foundation of National Excellent Doctoral Dissertation of China(201444)the 111 Project(111-2-05).
文摘Programmable metasurface enables controlling electromagnetic (EM) waves in real time. By programming the states of active device embedded in metasurface element, the EM properties of the digital metasurface can be changed quickly without redesigning their structures. However, large numbers of long-distance wires are required to connect the programmable metasurface to provide the coded signals from field programmable gate array (FPGA) when controlling the metasurface at a long distance, which is complicated and inconvenient. Here, we propose an infrared-controlled programmable metasurface that can be programmed remotely. The infrared transceiver is able to switch the coding sequences stored in the FPGA controller, thus controlling the voltage on the varactors integrated in the metasurface. Experiment is performed at microwave frequencies, and the measured results verify that the scattering beams of the metasurface sample can be changed remotely by using infrared ray. The proposed infrared-controlled programmable metasurface opens up avenues for constructing a new class of remotely-tuning dynamic metasurfaces.
基金Supported by National Natural Science Foundation of China under Grant Nos.11174088,11175067,11274124
文摘We have investigated the transport properties of the Dirac fermions through a ferromagnetic barrier junction on the surface of a strong topologicM insulator. The current-voltage characteristic curve and the tunneling conductance are calculated theoretically. Two interesting transport features are predicted: observable negative differential conductances and linear conductances tunable from unit to nearly zero. These features can be magnetically manipulated simply by changing the spacial orientation of the magnetization. Our results may contribute to the development of high-speed switching and functional applications or electricalIy controlled magnetization switching.