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Nano Dimension - Volume:1 Issue: 1, Summer 2010

International Journal of Nano Dimension
Volume:1 Issue: 1, Summer 2010

  • تاریخ انتشار: 1388/10/11
  • تعداد عناوین: 8
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  • E. Biazar, M.T. Khorasani, D. Zaeifi Page 1
    Peripheral nerve injuries (PNI) can lead to lifetime loss of function and disfigurement. Different methods such as conventional allograft procedures and using of biological tubes have problems for damaged peripheral nerves reconstruction. Designed scaffolds with natural and synthetic materials are now widely used in the reconstruction of damaged tissues. Utilization of absorbable and non-absorbable synthetic and natural polymers with unique characteristics can be an appropriate solution to repair damaged nerve tissues. Polymeric nanofibrous scaffolds with properties similar to neural structure can be more effective in the reconstruction process. Better cell adhesion and migration, more guiding of axons and structural features such as porosity provide clearer role of nanofibers for the restoration of neural tissues. In this paper, basic concepts of peripheral nerve injury, types of artificial and natural guides and the methods to improve the performance of tubes like orientation, nanotechnology applications for nerve reconstruction, fiber and nanofibers, electrospinning methods and their application in the peripheral nerve reconstruction have been reviewed.
  • S. Jalili, R. Vaziri Page 25
    First principle calculations were performed using Density functional theory within the local spin density approximation (LSDA) to understand the electronic properties of Au(100)+TBT system and compare the results with Au(100) and bulk Au properties. Band structure, the total DOS and charge density for these materials are calculated. We found that the HOMO for Au(100)+TBT becomes broader than Au(100) and bulk Au and d orbitals have the most contribution in covalent band. The electron densities overlap between Au atoms implies a large covalent bonding. Our calculations indicate that conjugated systems such as (TBT) enhance electric conductance.
  • M. Ghane, B. Sadeghi, A.R. Jafari, A.R. Paknejhad Page 33
    In the present work, we report the synthesis of binary nano metal oxides such as Zinc /Copper Oxide via novel dry synthetic methods such as thermal decomposition of oxalate precursor. The synthesis route involves facile solid-phase mechanochemical activation of a physical mixture of simple copper/zinc salts and oxalic acid, followed by calcination of the as-ground oxalate precursors at 450◦C. X-ray powder diffractometry (XRD), infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) were used to the thermal spectroscopic, structural, morphological characterization and surface area determination of the product respectively. An average nanocrystallite size of 5.0 nm was obtained for Zn/Cu, as estimated by the Scherrer’s equation.
  • M. Shahmohammadi, R. Jahandideh, A. Behnamghader, M. Rangie Page 41
    The aim of this study was to investigate the sol gel synthesis of HA/FA nanoparticles and the possible formation of TCP phase or unstoichiometric calcium deficient hydroxyapatite (CDHA) from the precursors with a Ca/P ratio of 1.62. In order to prepare the sol, the solutions of Triethyl phosphite, ammonium fluoride and calcium nitrate in ethanol were used respectively as P, F and Ca precursors.The crystallinity, particle and crystallite size, powder morphology, chemical structure and phase analysis were investigated by SEM, XRD, FT-IR and Zeta sizer experiment. A multiphase compound containing hydroxyapatite (HA) and fluoroapatite (FA) nanoparticles and calcium deficient hudroxyapatite (CDHA) agglomerates was obtained. The size of the crystallites estimated from XRD patterns using Scherrer equation and the crystallinity of HA phase were about 5 nm and 66% respectively. The zeta sizer experiments for the dispersed particles in its own conditions showed an average size of 98 nm.
  • M. Kargar Razi, M. Khosravi, R. Sarraf Mamoory, M. Mohammadi Page 47
    According to the unique properties and many applications of nano gold powder, it was prepared from an acid leaching tail solution. The low value residual gold ions existed in acid leaching tail solution in Mouteh gold mine in Iran with fellow heavy metals as pollutants (Fe2+, Cu2+, and Zn2+). Preparation of nano gold particles is achieved by two steps: First, by addition of ammonia as separation step and second by using the suitable reagents for precipitation and extraction step. Control conditions include pH, residence time, temperature, agitation, molar ratio of reducing agents to reagents. The optimum results show that nano gold powder was prepared by temperature of 250 °C, urea to gold molar ratio of 3:1, and reduction time of 20 min. Also, heat treatment improves dispersion of nano sized gold particles. The properties of gold nano powders were evaluated by SEM, A.A and UV-Vis spectroscopy methods and the size of particles were about 80 to 90 nm.
  • M.S. Sadjadi, M. Meskinfam, H. Jazdarreh Page 57
    Bone like hydroxyapatite (nHAp) was synthesized via an in situ biomimetic process in presence of wheat starch. The effect of polymer concentration alteration on the final structure of nHAp was investigated. Formation of the nHAp at room temperature was confirmed by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). Size and morphology of the nHAp samples were characterized using scanning and transmission electron microscopy (SEM and TEM). Starch as a template agent has influence on shape of the HAp precipitated in its aqueous solution. It leads to formation of rode like nHAp which is similar to this inorganic component in natural bone.
  • A. Hosseinian, A.R. Mahjoub, M. Movahedi Page 65
    A new tris-chelate Cd(II) complex, [Cd(DADMBTZ)3](ClO3)2 has been successfully synthesized and characterized by IR, 1H, 13C NMR spectroscopy, elemental analysis and single crystal X-ray determination. The thermal behavior, UV-Vis and fluorescence spectra of compound were studied. In reaction with DADMBTZ, Cadmium (II) forms a tris-chelate complex with nearly C3 symmetry for coordination polyhedron, DADMBTZ acts as a bidentate ligand. In complex the ClO3- anions are symmetrically different. Complex makes 2-D and 3-D networks via N-H…O and N-H…N hydrogen bonds, respectively. The nanocomposite CdO-CdS have been prepared using [Cd(DADMBTZ)3](ClO3)2 as precursor via thermal decomposition. As-prepared CdO-CdS nanocomposite was characterized By X-ray diffraction measurements (XRD), scanning electron microscopy (SEM).
  • G.R. Shahhosseini, F. Asadifard, M. Enayatollahi, M. Shapourgan, R. Haghjo, S. Heidari Keshel Page 77
    Poly N-isopropylacrylamide was successfully grafted onto a polystyrene cell culture dish by gamma ray. In this study, the effect of a radiation dose (radiation absorbed dosages of 10, 20, 30, 40 KGy) under appropriate temperature and grafting conditions was investigated. The FTIR analysis showed the existence of the graft PNIPAAm on the substrate. The optimal value of the dose for grafting was 40 KGy at 50°C. The SEM and AFM images clearly showed that increasing the absorbed dose of radiation would increase the amount of grafting. Surface topography and graft thickness in AFM images of the radiated samples showed that the PNIPAAm at the absorbed dose of radiation was properly grafted. The thickness of these grafts was about 50–100 nm. The drop water contact angles of the best grafted sample at 37°C and 10°C were 55.3 ± 1.2o and 61.2 ± 0.9o respectively, which showed the hydrophilicity and hydrophobicity of the grafted surfaces. DSC analysis also revealed the LCST of the grafted sample to be 32°C. Thermo-responsive polymers were grafted to dishes covalently which allowed fibroblast cells to attach and proliferate at 37°C; the cells also detached spontaneously without using enzymes when the temperature dropped below 32°C. This characteristic proves that this type of grafted material has potential as a biomaterial for cell sheet engineering.