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Showing posts from August, 2012

Nano hydroxyapatite

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Hydroxyapatite, (Ca10(PO4)6(OH)2 is chemically similar to the mineral component of bones and teeth and so it is used widely for biomedical application due to the high bioactivity and biocompatibility. It is used for the coating of the implants because of the bioactive and biodegradable properties and for reducing the failure of the implants. Due to the chemical similarity between HA and mineralized bone of human tissue, synthetic HA exhibits strong affinity to host hard tissues. In order to achieve a good biocompatibility, high range bioactivity polyethylene, collagen, and chitosan (CTS) are used to modify the Hap as the polyamide has a great biocompatibility with human structure. Synthetic nano-HA materials HAp can be produced from biogenic materials like coral, seashell, eggshell, body fluids and by some chemical synthetic methods. Common chemical methods used to produce synthetic nanocrystalline HA include precipitation, hydrothermal, hydrolysis, mechanochemical and solgel. These te

Nanocluster to conduct magnetic plasmons

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Focusing light at nanoscale Normally, light cannot be focused to a spot smaller than the diffraction limit which is half its wavelength. However, in recent years researchers have succeeded in this direction by coupling it to plasmonic nanostructures in which conductive electrons can oscillate collectively at the surface of metals, called surface particle plasmons. The phenomenon is studied as a part of a subject known as “nanoplasmonics”, based on tailored metallic nanostructures. Plasmonic waveguides Electron plasmons are formed when electrons oscillate back and forth (like an electron dipole) while magnetic plasmons are formed when electrons oscillate in a circular fashion (like a magnetic dipole). Magnetic plasmonic wave guiding networks are better than electronic ones when it comes to small size and they are superior to their photonic counterparts because they can focus light to wavelengths dramatically below the so-called diffraction limit. Researchers at Rice University have made

Nano trees for dye-sensitized solar cells

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Researchers from the Applied Nano Tech & Science Lab at Korea Advanced Institute of Science and Technology, and the Laser Thermal Lab at UC Berkeley, US, have teamed up to enhance the efficiency of dye-sensitized solar cells. Dye-sensitized solar cells In the late 1960s it was discovered that illuminated organic dyes can generate electricity at oxide electrodes in electrochemical cells. In an effort to understand and simulate the primary processes in photosynthesis the phenomenon was studied at the University of California at Berkeley with chlorophyll extracted from spinach (bio-mimetic or bionic approach). On the basis of such experiments electric power generation via the dye sensitization solar cell (DSSC) principle was demonstrated in 1972. The dye-sensitized solar cell belonging to the group of thin film solar cells and s based on a semiconductor formed between a photo-sensitized anode and an electrolyte, a photo electrochemical system. The dye molecules are incorporated are of

Nanoparticle disposal and exposure

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Environmental pollution by carbon particles emitted by car exhaust, smoking and long term inhalation of dust of various origins cause chronic inflammation of the lungs and has link to rheumatoid arthritis. Similarly nanomaterials are reported to have health and safety implications for the manufacture, use and ultimate disposal of nanotechnology products and materials. Exposure to nanoparticles is found to have a serious impact on health and link to rheumatoid arthritis and the development of other serious autoimmune diseases. Nanotechnology products which if not handled appropriately may contribute to the generation of airborne pollutants causing risks to health. Research Researchers at Trinity College Dublin's School of Medicine have investigated whether there is a common underlying mechanism contributing to the development of autoimmune diseases in human cells due to the exposure nanoparticles. The researchers applied nanomaterials such as ultra fine carbon black, carbon nanotube

Nanoparticles in the environment

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Nanoparticles can be found in the environment due to natural processes and also from man-made sources. Metal nanoparticles occur in the environment due to the discharge of engineered nanoparticles and the natural transformation of metal ions into metal nanoparticles. The transformation mechanism, fates, behaviors, and effects of these nanoparticles in the environment are not clearly known. Finding Researchers at Chinese Academy of Sciences have found that sunlight induces reduction of Ionic Ag and Au to metallic nanoparticles and it is due to dissolved organic matter present in the aqueous environment. In rivers and other bodies of water, sunlight can help dissolved organic matter reduce silver and gold ions to form nanoparticles of the metals, according to researchers. Mechanism The dissolved organic matter (DOM) in environmental waters can mediate the reduction of ionic Ag and Au to their metallic nanoparticles under natural sunlight with the reduction mediated by super oxide from ph

Nanopaint

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The advances in nanotechnology continue to grow, with new findings every day. To cite one example, researchers are manipulating carbon nanotubes so that the way the tubes behave under stress can help solve problems that arise in the future of a building, a bridge, even an airplane. Nanomaterials have a lot of use in the construction industry.  Researchers at the University of Strathclyde, in Scotland have developed a paint containing carbon nanotubes that can spot microscopic faults in structures relying on the ability of the paint to carry an electrical current to record the development of minuscule faults which is difficult for visual inspection. Scientists at Rice University in Houston, Texas, have come up with a strain paint looking like clear varnish for spotting cracks using fluorescence manifested at the infrared end of the spectrum when deformed by tension or compression of nanotubes, which otherwise can not be spotted during a visual inspection. The fluorescence paint can be r

Nanozymes

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                              (courtesy : Cao Research Group, UF) A nanozyme is a gold nanoparticle combined with an endonuclease and DNA complementary to a specific target RNA sequence. When DNA-RNA recognition occurs, the endonuclease cleaves the target RNA site-specifically. Nanozyme is a promising alternative to RNA interference (RNAi) agents for controlling gene expression by cutting RNA selectively in cells, according to researchers at the University of Florida. They designed nanozymes to mimic RNA-induced silencing complexes (RISCs). The working components of RNAi, RISCs use strands from small interfering RNAs (siRNAs) and endonucleases to cleave RNA in cells. Nanozymes are gold nanoparticles decorated both with DNA sequences and endoribonucleases. The DNA sequences act like siRNA strands in that they complement the target RNAs and the nanozyme endoribonucleases, like RISC endoribonucleases, are capable of cleaving those target RNAs. Applications Nanozymes are nanoparticle-base