Third- and fourth-order accurate finite difference schemes for the first derivative of the square of the speed are developed, for both uniform and non-uniform grids, and applied in the study of a two-dimensional visco...Third- and fourth-order accurate finite difference schemes for the first derivative of the square of the speed are developed, for both uniform and non-uniform grids, and applied in the study of a two-dimensional viscous fluid flow through an irregular domain. The von Mises transformation is used to transform the governing equations, and map the irregular domain onto a rectangular computational domain. Vorticity on the solid boundary is expressed in terms of the first partial derivative of the square of the speed of the flow in the computational domain, and the schemes are used to calculate the vorticity at the computational boundary grid points using up to five computational domain grid points. In all schemes developed, we study the effect of coordinate clustering on the computed results.展开更多
OBJECTIVE To explore a novel pH-sensitive fluorescent probe for in vivo tumor imaging.METHODS Zn5 were obtained in 140℃ after mixed with Me OH,water,Zn(NO_3)2·6 H_2O,H4L and trimethylamine.The fluorescence spect...OBJECTIVE To explore a novel pH-sensitive fluorescent probe for in vivo tumor imaging.METHODS Zn5 were obtained in 140℃ after mixed with Me OH,water,Zn(NO_3)2·6 H_2O,H4L and trimethylamine.The fluorescence spectra of Zn5 with the same concentration in different pH aqueous solutions were detected.And the stability of Zn5 was investigated by time dependent fluorescence emission spectra of Zn5 in BSA aqueous solution and 5.0% serum solution.Then,the cytotoxicity of Zn5 was detected by MTT assays.To clarify whether a similar fluorescence response occurs in biological organisms,He La cells were pretreated with probe Zn5(0.5 μmol·L^(-1)) and fluorescence imaging were collected for targeting lysosomes in living cells because of lysosomes′ acidic microenvironment.The A375 tumor-bearing mice were used to assess the imaging ability of Zn5 in vivo.Mouse tumor xenografts were established by injection of A375 cells with 2×10~6 cells per flank.Probe(1 μg·g^(-1)) was administered to mice by injection.Images were obtained using IVIS Spectrum CT Imaging System.RESULTS There is a 11-fold intensity increasing as the pH values changing from 8 to 2.The almost unchanged emission intensities suggest Zn5 is stable in both BSA and serum.Zn5 has negligible cytotoxicity for He La,293 T and CHO-K1 cells.Zn5 can selectively display lysosomes in living cells.Both the 2D and 3D images in vivo distinguish the tumor from other tissues with good fluorescence contrast.CONCLUSION The high chemical stability,emission in the Vis/NIR range,pH sensitivity,a pKa located in the tumor pH range,and low toxicity make Zn5 is suitable for application as a pH-sensitive fluorescent probe for bio-imaging.展开更多
Wireless sensor networks consist of many small nodes with distributing devices to monitor conditions at different locations. Usually wireless sensor nodes are sprinkled in a sensor field grouping limited areas. This p...Wireless sensor networks consist of many small nodes with distributing devices to monitor conditions at different locations. Usually wireless sensor nodes are sprinkled in a sensor field grouping limited areas. This paper highlights the Enhanced Cluster Based Key management (ECBK) protocol to achieve secure data delivery based on clustering mechanism. This protocol gives more importance to Cluster Coordinator node, which is used to coordinate the members and provide protective communication among the sensor nodes to enhance reliability. In Enhanced Cluster Based Key management two types of nodes are deployed. The high power nodes form clusters with surrounding nodes to enable the routing process without interference. This paper introduces ECBK protocol that balances the load among the clusters, achieves high throughput, end to end delay will be reduced, routing overhead also reduced and also it prolongs the network lifetime. Simulation results show that the presence of high transmission nodes reduces the delay, load balance, routing overhead, and enhances the throughput increased by 45% compared to other similar methods.展开更多
By skeptics and undecided we refer to nodes in clustered social networks that cannot be assigned easily to any of the clusters.Such nodes are typically found either at the interface between clusters(the undecided)or a...By skeptics and undecided we refer to nodes in clustered social networks that cannot be assigned easily to any of the clusters.Such nodes are typically found either at the interface between clusters(the undecided)or at their boundaries(the skeptics).Identifying these nodes is relevant in marketing applications like voter targeting,because the persons represented by such nodes are often more likely to be affected in marketing campaigns than nodes deeply within clusters.So far this identification task is not as well studied as other network analysis tasks like clustering,identifying central nodes,and detecting motifs.We approach this task by deriving novel geometric features from the network structure that naturally lend themselves to an interactive visual approach for identifying interface and boundary nodes.展开更多
文摘Third- and fourth-order accurate finite difference schemes for the first derivative of the square of the speed are developed, for both uniform and non-uniform grids, and applied in the study of a two-dimensional viscous fluid flow through an irregular domain. The von Mises transformation is used to transform the governing equations, and map the irregular domain onto a rectangular computational domain. Vorticity on the solid boundary is expressed in terms of the first partial derivative of the square of the speed of the flow in the computational domain, and the schemes are used to calculate the vorticity at the computational boundary grid points using up to five computational domain grid points. In all schemes developed, we study the effect of coordinate clustering on the computed results.
基金supported by Distinguished Young Scholars(21525101)the NSFC(91422302,and 21371037)
文摘OBJECTIVE To explore a novel pH-sensitive fluorescent probe for in vivo tumor imaging.METHODS Zn5 were obtained in 140℃ after mixed with Me OH,water,Zn(NO_3)2·6 H_2O,H4L and trimethylamine.The fluorescence spectra of Zn5 with the same concentration in different pH aqueous solutions were detected.And the stability of Zn5 was investigated by time dependent fluorescence emission spectra of Zn5 in BSA aqueous solution and 5.0% serum solution.Then,the cytotoxicity of Zn5 was detected by MTT assays.To clarify whether a similar fluorescence response occurs in biological organisms,He La cells were pretreated with probe Zn5(0.5 μmol·L^(-1)) and fluorescence imaging were collected for targeting lysosomes in living cells because of lysosomes′ acidic microenvironment.The A375 tumor-bearing mice were used to assess the imaging ability of Zn5 in vivo.Mouse tumor xenografts were established by injection of A375 cells with 2×10~6 cells per flank.Probe(1 μg·g^(-1)) was administered to mice by injection.Images were obtained using IVIS Spectrum CT Imaging System.RESULTS There is a 11-fold intensity increasing as the pH values changing from 8 to 2.The almost unchanged emission intensities suggest Zn5 is stable in both BSA and serum.Zn5 has negligible cytotoxicity for He La,293 T and CHO-K1 cells.Zn5 can selectively display lysosomes in living cells.Both the 2D and 3D images in vivo distinguish the tumor from other tissues with good fluorescence contrast.CONCLUSION The high chemical stability,emission in the Vis/NIR range,pH sensitivity,a pKa located in the tumor pH range,and low toxicity make Zn5 is suitable for application as a pH-sensitive fluorescent probe for bio-imaging.
文摘Wireless sensor networks consist of many small nodes with distributing devices to monitor conditions at different locations. Usually wireless sensor nodes are sprinkled in a sensor field grouping limited areas. This paper highlights the Enhanced Cluster Based Key management (ECBK) protocol to achieve secure data delivery based on clustering mechanism. This protocol gives more importance to Cluster Coordinator node, which is used to coordinate the members and provide protective communication among the sensor nodes to enhance reliability. In Enhanced Cluster Based Key management two types of nodes are deployed. The high power nodes form clusters with surrounding nodes to enable the routing process without interference. This paper introduces ECBK protocol that balances the load among the clusters, achieves high throughput, end to end delay will be reduced, routing overhead also reduced and also it prolongs the network lifetime. Simulation results show that the presence of high transmission nodes reduces the delay, load balance, routing overhead, and enhances the throughput increased by 45% compared to other similar methods.
文摘By skeptics and undecided we refer to nodes in clustered social networks that cannot be assigned easily to any of the clusters.Such nodes are typically found either at the interface between clusters(the undecided)or at their boundaries(the skeptics).Identifying these nodes is relevant in marketing applications like voter targeting,because the persons represented by such nodes are often more likely to be affected in marketing campaigns than nodes deeply within clusters.So far this identification task is not as well studied as other network analysis tasks like clustering,identifying central nodes,and detecting motifs.We approach this task by deriving novel geometric features from the network structure that naturally lend themselves to an interactive visual approach for identifying interface and boundary nodes.
