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Xing Y.,University of Dayton | Xiong W.,University of Dayton | Zhu L.,University of Dayton | O'Sawa E.,NanoCarbon Research Institute Ltd. | And 3 more authors.
ACS Nano | Year: 2011

Because of their unique photoluminescence and magnetic properties, nanodiamonds (NDs) are promising for biomedical imaging and therapeutical applications. However, these biomedical applications will hardly be realized unless the potential hazards of NDs to humans and other biological systems are ascertained. Previous studies performed in our group and others have demonstrated the excellent biocompatibility of NDs in a variety of cell lines without noticeable cytotoxicity. In the present paper, we report the first genotoxicity study on NDs. Our results showed that incubation of embryonic stem cells with NDs led to slightly increased expression of DNA repair proteins, such as p53 and MOGG-1. Oxidized nanodiamonds (O-NDs) were demonstrated to cause more DNA damage than the pristine/raw NDs (R-NDs), showing the surface chemistry specific genotoxicity. However, the DNA damages caused by either the O-NDs or the R-NDs are much less severe than those caused by multiwalled carbon nanotubes (MWNTs) observed in our previous study. These findings should have important implications for future applications of NDs in biological applications. © 2011 American Chemical Society. Source

Blagoveshchenskii N.M.,RAS Institute for Physics and Power Engineering | Novikov A.G.,RAS Institute for Physics and Power Engineering | Osava E.,NanoCarbon Research Institute Ltd. | Rozhkova N.N.,Russian Academy of Sciences
Physics of the Solid State | Year: 2010

Data on quasi-elastic neutron scattering by a water dispersion of nanodiamonds and a pure water as a supporting system has been analyzed. The observed difference in the quasi-elastic neutron scattering spectra is interpreted using two different approaches developed to date for describing the behavior of a solvent in the cases of low and moderate concentrations of carbon nanoparticles (for example, fullerenes, nanotubes, ultradispersed diamonds). Within the first approach, it is assumed that the influence of dissolved nanoparticles leads to an insignificant change in the properties of the solvent. Within the second approach, the properties of the solvent are assumed to be invariable as compared to those of the pure liquid, except for a narrow boundary region of the order of two to three atomic layers near the surface of nanoparticles, where the properties of the solvent change drastically. The explanation of the effect within the second approach seems to be more reliable despite the apparent complication of the mathematical treatment of the experiment. © 2010 Pleiades Publishing, Ltd. Source

Korepanov V.I.,National Chiao Tung University | Witek H.,National Chiao Tung University | Okajima H.,National Chiao Tung University | Osawa E.,NanoCarbon Research Institute Ltd. | Hamaguchi H.-O.,National Chiao Tung University
Journal of Chemical Physics | Year: 2014

Raman spectroscopy of nano-scale materials is facing a challenge of developing a physically sound quantitative approach for the phonon confinement effect, which profoundly affects the phonon Raman band shapes of small particles. We have developed a new approach based on 3-dimensional phonon dispersion functions. It analyzes the Raman band shapes quantitatively in terms of the particle size distributions. To test the model, we have successfully obtained good fits of the observed phonon Raman spectra of diamond nanoparticles in the size range from 1 to 100 nm. © 2014 AIP Publishing LLC. Source

Oku T.,University of Shiga Prefecture | Takeda A.,University of Shiga Prefecture | Nagata A.,University of Shiga Prefecture | Kidowaki H.,University of Shiga Prefecture | And 6 more authors.
Materials Technology | Year: 2013

Organic solar cells have a potential for use in lightweight, flexible, inexpensive and large scale solar cells. However, significant improvements of photovoltaic efficiencies are mandatory for use in future solar power plants. One of the improvements is donor-acceptor proximity in the devices, which are called bulk heterojunction solar cells. Bulk heterojunction is an efficient method to generate free charge carriers, and the charge transfer is possible at the semiconductor interface. The purpose of the present work is to fabricate and characterise C 60 based solar cells with copper oxides, CuInS 2, phthalocyanines, porphyrin, poly-vinylcarbazole, nanodiamond, germanium and exciton diffusion blocking layers. In the present work, C 60 and fullerenol [C 60(OH) 10-12] were used for n-type semiconductors, and metal copper oxides, metal phthalocyanine derivative, porphyrin and poly-vinylcarbazole were used for p-type semiconductors. In addition, nanodiamond and germanium based molecules were added into the active layers of the solar cells. The novel aspect of the research is to investigate the relation between properties and microstructures of the solar cells using transmission electron microscopy, X-ray diffraction and electronic structure calculation. The impact of the research concerns the study of organic solar cells by means of microstructural analysis, property measurements and theoretical calculations. © 2013 W. S. Maney &Son Ltd. Source

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