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991.
A couple of non-convex search strategies, based on the genetic algorithm, are suggested and numerically explored in the context
of large-deflection analysis of planar, elastic beams. The first of these strategies is based on the stationarity of the energy
functional in the equilibrium state and may therefore be considered weak. The second approach, on the other hand, attempts
to directly solve the governing differential equation within an optimisation framework and such a solution may be thought
of as strong. Several numerical illustrations and verifications with ‘exact’ solutions, if available, are provided
For communication 相似文献
992.
Surface-modified superparamagnetic nanoparticles for drug delivery: preparation, characterization, and cytotoxicity studies 总被引:10,自引:0,他引:10
Superparamagnetic iron oxide nanoparticles have been used for many years as magnetic resonance imaging (MRI) contrast agents or in drug delivery applications. In this study, a novel approach to prepare magnetic polymeric nanoparticles with magnetic core and polymeric shell using inverse microemulsion polymerization process is reported. Poly(ethyleneglycol) (PEG)-modified superparamagnetic iron oxide nanoparticles with specific shape and size have been prepared inside the aqueous cores of AOT/n-Hexane reverse micelles and characterized by various physicochemical means such as transmission electron microscopy (TEM), infrared spectroscopy, atomic force microscopy (AFM), vibrating sample magnetometry (VSM), and ultraviolet/visible spectroscopy. The inverse microemulsion polymerization of a polymerizable derivative of PEG and a cross-linking agent resulted in a stable hydrophilic polymeric shell of the nanoparticles. The results taken together from TEM and AFM studies showed that the particles are spherical in shape with core-shell structure. The average size of the PEG-modified nanoparticles was found to be around 40-50 nm with narrow size distribution. The magnetic measurement studies revealed the superparamagnetic behavior of the nanoparticles with saturation magnetization values between 45-50 electromagnetic units per gram. The cytotoxicity profile of the nanoparticles on human dermal fibroblasts as measured by standard 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay showed that the particles are nontoxic and may be useful for various in vivo and in vitro biomedical applications. 相似文献
993.
Synthesis of palladium nanoparticles using a continuous flow polymeric micro reactor 总被引:1,自引:0,他引:1
A continuous flow polymeric micro reactor, fabricated using a negative photo resist SU-8 on a 10 x 10 cm PEEK (polyetheretherketone) substrate by standard UV lithography, was utilized to synthesize palladium nanoparticles. The nanoparticles were characterized by Transmission Electron Microscopy, Selected Area Electron Diffraction and X-ray Diffraction. The Pd nanoparticles synthesized in the micro reactor were found to have a narrower size distribution when compared with those obtained by the conventional batch process. 相似文献
994.
Cationic poly(lactide-co-glycolide) nanoparticles as efficient in vivo gene transfection agents 总被引:3,自引:0,他引:3
Kumar MN Mohapatra SS Kong X Jena PK Bakowsky U Lehr CM 《Journal of nanoscience and nanotechnology》2004,4(8):990-994
Poly(lactide-co-glycolide) (PLGA), a biocompatible and biodegradable polyester co-polymer of PLA and PGA, has been recognized for its ability to deliver genes. However, gene delivery by PLGA nanoparticles is limited by their negative charge and their poor transport through mucosal barriers. In this study, PLGA nanoparticles were surface modified with cationic chitosan in an effort to improve their gene delivery capability. PLGA nanoparticles were synthesized by emulsion-diffusion-evaporation technique using PVA-chitosan (PLGA1) or PVA-chitosan-PEG (PLGA2) blend as stabilizers. This method is reproducible and produces nanoparticles with hydrodynamic diameter <200 nm. The nanoparticles were characterized by zetasizer, photon correlation spectroscopy and atomic force microscopy. A549 epithelial cells were transfected in vitro with PLGA particles complexed with a reporter plasmid encoding green fluorescent protein. PLGA particles transferred EGFP gene, but were less efficient than the lipofectamine control. The nanoparticles were also tested for their ability to transport across the nasal mucosa in vivo in mice. The results show that both PLGA1 and PLGA2 facilitate gene delivery and expression in vivo with increased efficiency and without causing inflammation, as measured by IL-6. Together, these results indicate that chitosan-modified PLGA nanoparticles have greater potential as gene carriers. 相似文献
995.
996.
Wireless Networks - Unlike wired networks, wireless networks do not come with links. Rather, links have to be fashioned out of the ether by nodes choosing neighbors to connect to. Moreover the... 相似文献
997.
998.
999.
Flow of materials in rotary kilns used for sponge iron manufacture: Part II. Effect of kiln geometry
Amit Chatterjee A. V. Sathe P. K. Mukhopadhyay 《Metallurgical and Materials Transactions B》1983,14(3):383-392
The present work identifies the basic features of burden movement in a rotary kiln. The cold model study was conducted with
iron ore as the feed material to determine the influence of length to diameter ratio (L/D) of a rotary kiln on the filling degree, hold-up, and residence time of the charge. An empirical equation correlating different
operating variables has been derived on the basis of the experimental results. The influence of individual parameters under
different conditions on the residence time and back spillage has also been evaluated.
Formerly Joint Director, Research and Development, TISCO 相似文献
1000.
Spin-glass models of neural networks 总被引:1,自引:0,他引:1