WorldWideScience

Sample records for nanosized w2n surface

  1. Simulation, microstructure and microhardness of the nano-SiC coating formed on Al surface via laser shock processing

    International Nuclear Information System (INIS)

    Cui, C.Y.; Cui, X.G.; Zhao, Q.; Ren, X.D.; Zhou, J.Z.; Liu, Z.; Wang, Y.M.

    2014-01-01

    Highlights: • Nano-SiC coating is successfully fabricated on pure Al surface via LSPC. • Movement states of the nano-SiC particles are analyzed by FEM. • Formation mechanism of the nano-SiC coating is put forward and discussed. • Microhardness of the Al is significantly improved due to the nano-SiC coating. - Abstract: A novel method, laser shock processing coating (LSPC), has been developed to fabricate a particle-reinforced coating based on laser shock processing (LSP). In this study, a nano-SiC coating is successfully prepared on pure Al surface via LSPC. The surface and cross section morphologies as well as the compositions of nano-SiC coating are investigated. Moreover, a finite element method (FEM) is employed to clarify the formation process of nano-SiC coating. On the basis of the above analyzed results, a possible formation mechanism of the nano-SiC coating is tentatively put forward and discussed. Furthermore, the nano-SiC coating shows superior microhardness over the Al substrate

  2. Surface energy effect on free vibration of nano-sized piezoelectric double-shell structures

    Science.gov (United States)

    Fang, Xue-Qian; Zhu, Chang-Song; Liu, Jin-Xi; Liu, Xiang-Lin

    2018-01-01

    Combining Goldenveizer-Novozhilov shell theory, thin plate theory and electro-elastic surface theory, the size-dependent vibration of nano-sized piezoelectric double-shell structures under simply supported boundary condition is presented, and the surface energy effect on the natural frequencies is discussed. The displacement components of the cylindrical nano-shells and annular nano-plates are expanded as the superposition of standard Fourier series based on Hamilton's principle. The total stresses with consideration of surface energy effect are derived, and the total energy function is obtained by using Rayleigh-Ritz energy method. The free vibration equation is solved, and the natural frequency is analyzed. In numerical examples, it is found that the surface elastic constant, piezoelectric constant and surface residual stress show different effects on the natural frequencies. The effect of surface piezoelectric constant is the maximum. The effect of dimensions of the double-shell under different surface material properties is also examined.

  3. MD simulation analysis of resin filling into nano-sized pore formed on metal surface

    Science.gov (United States)

    Mori, Hodaka; Matubayasi, Nobuyuki

    2018-01-01

    All-atom MD simulation was conducted for the filling of epoxy resin into a nano-sized pore formed on aluminum surface. The resin species examined were polyphenol mixed with polyglycidylether of o-cresol formaldehyde novolac and their oligomers formed through ring-opening reactions. The degree of oligomerization was varied from 0.5 to 2.5 nm in terms of the radius of gyration, and the radius of the cylindrical pore was fixed at 2.5 nm. It was observed that a small resin penetrates into the pore along the wall, while larger resins move rather uniformly in the pore. The maximum density in the pore achieved with pushing was then seen to be larger when the resin is smaller. It was found that when the radius of gyration of resin is larger than half the pore radius, the resin density in the pore does not reach half the bulk density of the resin. This implies that the resin-resin interaction inhibits the filling of the nano-sized pore.

  4. Durable Lotus-effect surfaces with hierarchical structure using micro- and nanosized hydrophobic silica particles.

    Science.gov (United States)

    Ebert, Daniel; Bhushan, Bharat

    2012-02-15

    Surfaces with a very high apparent water contact angle (CA) and low water contact angle hysteresis (CAH) exhibit many useful characteristics, among them extreme water repellency, low drag for fluid flow, and a self-cleaning effect. The leaf of the Lotus plant (Nelumbo nucifera) achieves these properties using a hierarchical structure with roughness on both the micro- and nanoscale. It is of great interest to create durable surfaces with the so-called "Lotus effect" for many important applications. In this study, hierarchically structured surfaces with Lotus-effect properties were fabricated using micro- and nanosized hydrophobic silica particles and a simple spray method. In addition, hierarchically structured surfaces were prepared by spraying a nanoparticulate coating over a micropatterned surface. To examine the similarities between surfaces using microparticles versus a uniform micropattern as the microstructure, CA and CAH were compared across a range of pitch values for the two types of microstructures. Wear experiments were performed using an atomic force microscope (AFM), a ball-on-flat tribometer, and a water jet apparatus to verify multiscale wear resistance. These surfaces have potential uses in engineering applications requiring Lotus-effect properties and high durability. Copyright © 2011 Elsevier Inc. All rights reserved.

  5. Surface smoothing effect of an amorphous thin film deposited by atomic layer deposition on a surface with nano-sized roughness

    Directory of Open Access Journals (Sweden)

    W. S. Lau

    2014-02-01

    Full Text Available Previously, Lau (one of the authors pointed out that the deposition of an amorphous thin film by atomic layer deposition (ALD on a substrate with nano-sized roughness probably has a surface smoothing effect. In this letter, polycrystalline zinc oxide deposited by ALD onto a smooth substrate was used as a substrate with nano-sized roughness. Atomic force microscopy (AFM and cross-sectional transmission electron microscopy (XTEM were used to demonstrate that an amorphous aluminum oxide thin film deposited by ALD can reduce the surface roughness of a polycrystalline zinc oxide coated substrate.

  6. Significantly improving trace thallium removal from surface waters during coagulation enhanced by nanosized manganese dioxide.

    Science.gov (United States)

    Huangfu, Xiaoliu; Ma, Chengxue; Ma, Jun; He, Qiang; Yang, Chun; Jiang, Jin; Wang, Yaan; Wu, Zhengsong

    2017-02-01

    Thallium (Tl) is an element of high toxicity and significant accumulation in human body. There is an urgent need for the development of appropriate strategies for trace Tl removal in drinking water treatment plants. In this study, the efficiency and mechanism of trace Tl (0.5 μg/L) removal by conventional coagulation enhanced by nanosized manganese dioxide (nMnO 2 ) were explored in simulated water and two representative surface waters (a river water and a reservoir water obtained from Northeast China). Experimental results showed that nMnO 2 significantly improve Tl(I) removal from selected waters. The removal efficiency was dramatically higher in the simulated water, demonstrating by less than 0.1 μg/L Tl residual. The enhancement of trace Tl removal in the surface waters decreased to a certain extent. Both adjusting water pH to alkaline condition and preoxidation of Tl(I) to Tl(III) benefit trace Tl removal from surface waters. Data also indicated that competitive cation of Ca 2+ decreased the efficiency of trace Tl removal, resulting from the reduction of Tl adsorption on nMnO 2 . Humic acid could largely low Tl removal efficiency during nMnO 2 enhanced coagulation processes. Trace elemental Tl firstly adsorbed on nMnO 2 and then removed accompanying with nMnO 2 settling. The information obtained in the present study may provide a potential strategy for drinking water treatment plants threatened by trace Tl. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Effective removal of trace thallium from surface water by nanosized manganese dioxide enhanced quartz sand filtration.

    Science.gov (United States)

    Huangfu, Xiaoliu; Ma, Chengxue; Ma, Jun; He, Qiang; Yang, Chun; Zhou, Jian; Jiang, Jin; Wang, Yaan

    2017-12-01

    Thallium (Tl) has drawn wide concern due to its high toxicity even at extremely low concentrations, as well as its tendency for significant accumulation in the human body and other organisms. The need to develop effective strategies for trace Tl removal from drinking water is urgent. In this study, the removal of trace Tl (0.5 μg L -1 ) by conventional quartz sand filtration enhanced by nanosized manganese dioxide (nMnO 2 ) has been investigated using typical surface water obtained from northeast China. The results indicate that nMnO 2 enhanced quartz sand filtration could remove trace Tl(I) and Tl(III) efficiently through the adsorption of Tl onto nMnO 2 added to a water matrix and onto nMnO 2 attached on quartz sand surfaces. Tl(III)-HA complexes might be responsible for higher residual Tl(III) in the effluent compared to residual Tl(I). Competitive Ca 2+ cations inhibit Tl removal to a certain extent because the Ca 2+ ions will occupy the Tl adsorption site on nMnO 2 . Moreover, high concentrations of HA (10 mgTOC L -1 ), which notably complexes with and dissolves nMnO 2 (more than 78%), resulted in higher residual Tl(I) and Tl(III). Tl(III)-HA complexes might also enhance Tl(III) penetration to a certain extent. Additionally, a higher pH level could enhance the removal of trace Tl from surface water. Finally, a slight increase of residual Tl was observed after backwash, followed by the reduction of the Tl concentration in the effluent to a "steady" state again. The knowledge obtained here may provide a potential strategy for drinking water treatment plants threatened by trace Tl. Copyright © 2017. Published by Elsevier Ltd.

  8. Adhesion of nano-sized particles to the surface of bacteria: mechanistic study with the extended DLVO theory.

    Science.gov (United States)

    Hwang, Geelsu; Ahn, Ik-Sung; Mhin, Byung Jin; Kim, Ju-Young

    2012-09-01

    Due to the increasing production and application of nanoparticles, their release into the environment would be inevitable, which requires a better understanding of their fate in the environment. When considering their toxic behavior or biodegradation as their fate, their adhesion to the cell surface must be the first step to be thoroughly studied. In this study, nano-sized polymeric particles of urethane acrylate with various hydrophobicity and ionic properties were synthesized as model nanoparticles, and their adhesion to Pseudomonas putida strains was monitored. The higher hydrophobicity and positive charge density on the particle surface exhibited the larger adhesion to the bacteria, whereas negative charge density on the particle hindered their adhesion to the bacteria, albeit high hydrophobicity of particle. These observations were successfully explained with the extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Surface Modification, Characterization and Photocatalytic Performance of Nano-Sized Titania Modified with Silver and Bentonite Clay

    Directory of Open Access Journals (Sweden)

    Neetu Divya

    2009-12-01

    Full Text Available In many textile industries dyes are used as coloring agents. Advanced oxidation processes are used for degrading or removing color from dye baths. Catalysts play a key role in these industries for the treatment of water. Solid catalysts are usually composed of metals that form supports onto the surface and create metal particles with high surface areas. TiO2 composites containing transition metal ions (silver and/or bentonite clay were prepared. Photocatalytic efficiencies have been investigated for the degradation of Orange G an azo dye. Various analytical techniques were used to characterize the surface properties of nano-sized titania modified using silver and/or bentonite clay. Scanning electron microscopy (SEM, Transmission electron microscopy (TEM, X-ray diffraction (XRD and FTIR analyses showed that TiO2 (10 ± 2 nm and Ag (2 to 3 nm particles were supported on the surface of the bentonite clay and the size was in the range of 100 ± 2 nm. The modified catalysts P-25 TiO2/Bentonite/Ag and P-25 TiO2/Ag were found to be very active for the photocatalytic decomposition of Orange G. The percent decolorization in 60 min was 98% with both P-25 TiO2/Ag and P-25 TiO2/Bentonite/Ag modified catalysts. Whereas mineralization achieved in 9 hr were 68% and 71% with P-25 TiO2/Bentonite/Ag and P-25 TiO2/Ag catalyst respectively. © 2009 BCREC UNDIP. All rights reserved[Received: 30 October 2009, Revised: 20 November 2009, Accepted: 21 November 2009][How to Cite: N. Divya, A. Bansal, A. K. Jana. (2009. Surface Modification, Characterization and Photocatalytic Performance of Nano-Sized Titania Modified with Silver and Bentonite Clay. Bulletin of Chemical Reaction Engineering and Catalysis, 4(2: 43-53.  doi:10.9767/bcrec.4.2.1249.43-53][How to Link/ DOI: http://dx.doi.org/10.9767/bcrec.4.2.1249.43-53 || or local: http://ejournal.undip.ac.id/index.php/bcrec/article/view/1249

  10. Nano-sized emission from commercially available paints used for indoor surfaces during drying.

    Science.gov (United States)

    Jørgensen, Rikke Bramming; Hveding, Ingrid Grav; Solheim, Karoline

    2017-12-01

    Consumers worry about the presence of nano-particles in paints and the risk of exposure. As a result, the paint industry now omits marketing paints as containing nanoparticles. The industry claims that no nanoparticles are released into the indoor environment; this, however, has yet to be documented. In this study, the emission of nano-sized emission from four indoor paints was investigated. The emission was studied for both base and full-pigmented versions of the paints, which consisted of three water-borne acrylic paints and one solvent-borne alkyd paint. All experiments were performed twice in a 6.783 m 3 stainless-steel test chamber under standardized conditions (22.98 °C, 50.08% RH, air exchange rate 0.48 h -1 ). Emissions during the paint-drying period were measured using a TSI Fast Mobility Particle Sizer (FMPS) measuring the number concentration of nano-particles and the size distribution in the range 5.6-560 nm. The results from the solvent-borne paint showed the highest concentration, with a mean concentration of 3.2·10 5 particles/cm 3 and a maximum of 1.4·10 6 particles/cm 3 . This paint also had the smallest particle size distribution, with 9.31 nm particles as the most dominant particle size. The results from this study showed that the exposure to nanoparticles for the residents evaluated over a 7 or 28 day period was low and that interior paints are probably not very important when it comes to identifying products that release nano-particles into indoor environments. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Effect of Ag-doping of nanosized FeAlO system on its structural, surface and catalytic properties

    Directory of Open Access Journals (Sweden)

    Laila I. Ali

    2016-11-01

    Full Text Available The effects of Ag2O-doping on the physicochemical, surface and catalytic properties of FeAlO system with various extents of Fe2O3 loading have been investigated. The dopant concentration was changed between 1.5 and 4.0 mol % Ag2O. Pure and variously doped solids were subjected to heat treatment at 400–800 °C. The techniques employed for characterization of catalysts were TG/DTG, XRD, N2-adsorption at −196 °C and the catalytic decomposition of H2O2 at 25–40 °C. The results obtained revealed that, the investigated catalysts consisted of nanosized γ-Al2O3 phase. The textural properties including SBET, porosity and St were modified by Ag2O-doping. The doping process with Ag-species improves the catalytic activity of FeAlO system. Increasing the precalcination temperature from 400 to 800 °C increases the catalytic activity of 3.5% AgFeAlO with 1.9-fold toward H2O2 decomposition at 30 °C. Furthermore, the maximum increase in the catalytic activity due to doping with 3.5 mol % Ag2O at 30 °C attained about 15.1-fold for the solids calcined at 800 °C.

  12. Self-Similar Micron-Size and Nanosize Drops of Liquid Generated by Surface Acoustic Waves

    Science.gov (United States)

    Taller, Daniel; Go, David B.; Chang, Hsueh-Chia

    2012-11-01

    A planar surface acoustic wave on a solid substrate and its radiated sound into a static liquid drop produce time-averaged, exponentially decaying acoustic and electric Maxwell pressures near the contact line. These localized contact-line pressures are shown to generate two sequences of hemispherical satellite droplets at the tens of microns and submicron scales, both obeying self-similar exponential scaling but with distinct exponents that correspond to viscous dissipation and field leakage length scales, respectively. The acoustic pressure becomes dominant when the film thickness exceeds (1/4π) of the surface acoustic wave wavelength and it affects the shape and stability of the mother drop. The Maxwell pressure of the nanodrops, which exceeds ten atmospheres, is sensitive to the contact angle.

  13. Nanosized polycrystalline diamond cladding for surface protection of zirconium nuclear fuel tubes

    Czech Academy of Sciences Publication Activity Database

    Kratochvílová, Irena; Škoda, R.; Škarohlíd, J.; Ashcheulov, Petr; Jäger, Aleš; Racek, Jan; Taylor, Andrew; Shao, L.

    2014-01-01

    Roč. 214, č. 11 (2014), s. 2600-2605 ISSN 0924-0136 R&D Projects: GA TA ČR TA01011165; GA MŠk(CZ) LM2011026 EU Projects: European Commission(XE) 238201 - MATCON Institutional support: RVO:68378271 Keywords : polycrystalline diamond film * nuclear fuel cladding protection Subject RIV: JK - Corrosion ; Surface Treatment of Materials Impact factor: 2.236, year: 2014

  14. Manufacture of nanosized apatite coatings on titanium with different surface treatments using a supersaturated calcification solution

    Directory of Open Access Journals (Sweden)

    Adrian Paz Ramos

    Full Text Available The biomimetic method is used for the deposition of calcium phosphate coatings (Ca - P on the surface of different biomaterials. However, the application of this method requires long exposure times in order to obtain a suitable layer thickness for its use in medical devices. In this paper, we present a fast approach to obtain apatite coatings on titanium, using a combination of supersaturated calcification solution (SCS with chemical modification of the titanium surface. Also, it was evaluated the effect of four different surface treatments on the apatite deposition rate. Commercially pure titanium plates were activated by chemical or thermochemical treatments. Then, the activated samples were immersed in a solution with high content of calcium and phosphate ions at 37 ºC for 24 h, mimicking the physiological conditions. The coatings were studied by Fourier transform infrared spectroscopy (FTIR, X-ray diffraction (XRD, scanning electron microscopy (SEM and energy dispersive X-ray spectroscopy (EDX. The use of SCS solutions allowed the formation of crystalline hydroxyapatite coatings within a period of 24 h with a thickness between 1 and 5.3 µm. Besides, precipitates of hydroxyapatite nanoparticles with a globular configuration, forming aggregates with submicrometer size, were found in SCS solutions.

  15. Effects of {gamma}-irradiation and ageing on surface and catalytic properties of nano-sized Cu O/Mg O system

    Energy Technology Data Exchange (ETDEWEB)

    El-Molla, S. A. [Ain Shams University, Faculty of Education, Chemistry Deparment, Roxy, Heliopolis, 11757 Cairo (Egypt); Ismail, S. A.; Ibrahim, M. M., E-mail: saharelmolla@yahoo.com [National Center for Radiation Research and Technology, Nasr City, P.O. Box 29, 11731 Cairo (Egypt)

    2011-07-01

    0.2 Cu O/Mg O system prepared by impregnation method was calcined at 350 and 450 C. The effects of {gamma}-rays (0.2-1.6 MGy) on its structure, surface and catalytic properties were investigated by using XRD, N{sub 2}-adsorption at -196 C and catalytic conversion of isopropanol at 150-275 C using a flow technique. The results revealed that the investigated solids consisted of nano-sized Mg O as a major phase besides Cu O and trace amount of Cu{sub 2}O. {gamma}-Irradiation of the solids investigated exerted measurable changes in their surface and catalytic properties dependent on the calcination temperature and dose of irradiation. The catalysts investigated acted as active dehydrogenation solids. The five years-ageing of different solids showed limited changes of their surface and catalytic properties indicating a good catalytic stability of the irradiated prepared solids. (Author)

  16. Effects of γ-irradiation and ageing on surface and catalytic properties of nano-sized Cu O/Mg O system

    International Nuclear Information System (INIS)

    El-Molla, S. A.; Ismail, S. A.; Ibrahim, M. M.

    2011-01-01

    0.2 Cu O/Mg O system prepared by impregnation method was calcined at 350 and 450 C. The effects of γ-rays (0.2-1.6 MGy) on its structure, surface and catalytic properties were investigated by using XRD, N 2 -adsorption at -196 C and catalytic conversion of isopropanol at 150-275 C using a flow technique. The results revealed that the investigated solids consisted of nano-sized Mg O as a major phase besides Cu O and trace amount of Cu 2 O. γ-Irradiation of the solids investigated exerted measurable changes in their surface and catalytic properties dependent on the calcination temperature and dose of irradiation. The catalysts investigated acted as active dehydrogenation solids. The five years-ageing of different solids showed limited changes of their surface and catalytic properties indicating a good catalytic stability of the irradiated prepared solids. (Author)

  17. Study of the surface modification with oleic acid of nanosized HfO{sub 2} synthesized by the polymerized complex derived sol-gel method

    Energy Technology Data Exchange (ETDEWEB)

    Ramos-Gonzalez, R., E-mail: rramos.phd@gmail.com [Centro de Investigacion en Quimica Aplicada, Blvd. Enrique Reyna Hermosillo No. 140, Saltillo, Coahuila 25250 (Mexico); Garcia-Cerda, L.A. [Centro de Investigacion en Quimica Aplicada, Blvd. Enrique Reyna Hermosillo No. 140, Saltillo, Coahuila 25250 (Mexico); Quevedo-Lopez, M.A. [University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080-3021 (United States)

    2012-06-01

    The synthesis of nanosized hafnium oxide by the polymerized complex derived sol-gel method is reported. The structural and morphological characterization of the HfO{sub 2} was carried out by X-ray diffraction and scanning electron microscopy. The surface of hafnium oxide nanoparticles was modified by capping with oleic acid. The nanoparticle surface area was measured by the gas adsorption technique in order to determine the minimal amount of oleic acid needed to obtain a uniform coverage of the hafnium oxide. The existence of organic layer can be confirmed by Fourier transform spectroscopy, solid state nuclear magnetic resonance spectroscopy, thermal gravimetric analysis and transmission electron microscopy. The FTIR and solid state NMR results reveal that oleic acid is chemisorbed as a carboxylate onto the HfO{sub 2} nanoparticle surface and confirm the formation of a monomolecular layer of oleic acid surrounding the HfO{sub 2}. The cover density of oleic acid on the HfO{sub 2} increases with the amount of oleic acid used to modify the nanoparticles and the surface properties of HfO{sub 2} nanoparticles modified with oleic acid change from hydrophilic to hydrophobic.

  18. Effects of prenatal exposure to surface-coated nanosized titanium dioxide (UV-Titan. A study in mice

    Directory of Open Access Journals (Sweden)

    Vibenholt Anni

    2010-06-01

    Full Text Available Abstract Background Engineered nanoparticles are smaller than 100 nm and designed to improve or achieve new physico-chemical properties. Consequently, also toxicological properties may change compared to the parent compound. We examined developmental and neurobehavioral effects following maternal exposure to a nanoparticulate UV-filter (UV-titan L181. Methods Time-mated mice (C57BL/6BomTac were exposed by inhalation 1h/day to 42 mg/m3 aerosolized powder (1.7·106 n/cm3; peak-size: 97 nm on gestation days 8-18. Endpoints included: maternal lung inflammation; gestational and litter parameters; offspring neurofunction and fertility. Physicochemical particle properties were determined to provide information on specific exposure and deposition. Results Particles consisted of mainly elongated rutile titanium dioxide (TiO2 with an average crystallite size of 21 nm, modified with Al, Si and Zr, and coated with polyalcohols. In exposed adult mice, 38 mg Ti/kg was detected in the lungs on day 5 and differential cell counts of bronchoalveolar lavage fluid revealed lung inflammation 5 and 26-27 days following exposure termination, relative to control mice. As young adults, prenatally exposed offspring tended to avoid the central zone of the open field and exposed female offspring displayed enhanced prepulse inhibition. Cognitive function was unaffected (Morris water maze test. Conclusion Inhalation exposure to nano-sized UV Titan dusts induced long term lung inflammation in time-mated adult female mice. Gestationally exposed offspring displayed moderate neurobehavioral alterations. The results are discussed in the light of the observed particle size distribution in the exposure atmosphere and the potential pathways by which nanoparticles may impart changes in fetal development.

  19. Effects of prenatal exposure to surface-coated nanosized titanium dioxide (UV-Titan). A study in mice.

    Science.gov (United States)

    Hougaard, Karin S; Jackson, Petra; Jensen, Keld A; Sloth, Jens J; Löschner, Katrin; Larsen, Erik H; Birkedal, Renie K; Vibenholt, Anni; Boisen, Anne-Mette Z; Wallin, Håkan; Vogel, Ulla

    2010-06-14

    Engineered nanoparticles are smaller than 100 nm and designed to improve or achieve new physico-chemical properties. Consequently, also toxicological properties may change compared to the parent compound. We examined developmental and neurobehavioral effects following maternal exposure to a nanoparticulate UV-filter (UV-titan L181). Time-mated mice (C57BL/6BomTac) were exposed by inhalation 1h/day to 42 mg/m(3) aerosolized powder (1.7.10(6) n/cm(3); peak-size: 97 nm) on gestation days 8-18. Endpoints included: maternal lung inflammation; gestational and litter parameters; offspring neurofunction and fertility. Physicochemical particle properties were determined to provide information on specific exposure and deposition. Particles consisted of mainly elongated rutile titanium dioxide (TiO2) with an average crystallite size of 21 nm, modified with Al, Si and Zr, and coated with polyalcohols. In exposed adult mice, 38 mg Ti/kg was detected in the lungs on day 5 and differential cell counts of bronchoalveolar lavage fluid revealed lung inflammation 5 and 26-27 days following exposure termination, relative to control mice. As young adults, prenatally exposed offspring tended to avoid the central zone of the open field and exposed female offspring displayed enhanced prepulse inhibition. Cognitive function was unaffected (Morris water maze test). Inhalation exposure to nano-sized UV Titan dusts induced long term lung inflammation in time-mated adult female mice. Gestationally exposed offspring displayed moderate neurobehavioral alterations. The results are discussed in the light of the observed particle size distribution in the exposure atmosphere and the potential pathways by which nanoparticles may impart changes in fetal development.

  20. Preparation and characterization of nanosized P(NIPAM-MBA) hydrogel particles and adsorption of bovine serum albumin on their surface.

    Science.gov (United States)

    Zhu, Xiaoli; Gu, Xiangling; Zhang, Lina; Kong, Xiang-Zheng

    2012-09-24

    Thermosensitive polymer hydrogel particles with size varying from 480 to 620 nm were prepared through precipitation copolymerization of N-isopropylacrylamide with N,N'-methylenebisacrylamide (MBA) in water with ammonium persulfate as the initiator. Only polymer hydrogels without any coagula were obtained when MBA concentration in the monomer mixture was kept between 2.5 and 10.0 wt%; with increased MBA concentration, the monomer conversion was enhanced, the size of the hydrogels was increased, and their shrinking was lessened when heated from 25°C to 40°C. Bovine serum albumin adsorption on the surface of the hydrogels of different MBA content was measured at different pH levels and under different temperatures. The results demonstrated that the adsorption of the protein on the hydrogels could be controlled by adjusting the pH, the temperature of adsorption, and the crosslinking in the hydrogels. The results were interpreted, and the mechanisms of the polymerization were proposed.

  1. Plasmid DNA is released from nanosized acicular material surface by low molecular weight oligonucleotides: exogenous plasmid acquisition mechanism for penetration intermediates based on the Yoshida effect.

    Science.gov (United States)

    Yoshida, N; Ide, K

    2008-10-01

    When a colloidal solution consisting of nanosized acicular material and bacterial cells is stimulated with sliding friction at the interface between the hydrogel and interface-forming material where the frictional coefficient increases rapidly, the nanosized acicular material accompanying the bacterial cells forms a penetration intermediate. This effect is known as the Yoshida effect in honor of its discoverer. Through the Yoshida effect, a novel property in which penetration intermediates incorporate exogenous plasmid DNA has been identified. This report proposes a possible mechanism for exogenous plasmid acquisition by penetration intermediates in the Yoshida effect. Escherichia coli cells, pUC18, and chrysotile were used as recipient cells, plasmid DNA, and nanosized acicular material, respectively. Even when repeatedly washing the mixture consisting of pUC18 and chrysotile, transformation efficiency by pUC18 was stable. Accordingly, pUC18 adsorbed onto chrysotile was introduced into recipient E. coli cells. At saturation, the amount of pUC18 adsorbed onto chrysotile was 0.8-1.2 microg/mg. To investigate whether pUC18 adsorbed on chrysotile is replicated by polymerase, polymerase chain reaction (PCR) was carried out with the chrysotile. Amplification of the beta-lactamase gene coded in pUC18, which was adsorbed onto chrysotile, was strongly inhibited. This suggests that DNA adsorbed onto chrysotile is not replicated in vivo. When we searched for substances to release pUC18 adsorbed onto chrysotile, we found that a 300-bp single- or double-stranded segment of DNA releases pUC18 from chrysotile. Competitive adsorption onto chrysotile between double-stranded DNA and pUC18 was then examined through the Yoshida effect. The 310- and 603-bp double-stranded nucleotides caused 50% competitive inhibition at the same molar ratio with pUC18. Hence, the adsorbed region of pUC18 is about 300 bp in length. As the culture period for recipient cells increases, transformation

  2. Nanosizing techniques for improving bioavailability of drugs.

    Science.gov (United States)

    Al-Kassas, Raida; Bansal, Mahima; Shaw, John

    2017-08-28

    The poor solubility of significant number of Active Pharmaceutical Ingredients (APIs) has become a major challenge in the drug development process. Drugs with poor solubility are difficult to formulate by conventional methods and often show poor bioavailability. In the last decade, attention has been focused on developing nanocrystals for poorly water soluble drugs using nanosizing techniques. Nanosizing is a pharmaceutical process that changes the size of a drug to the sub-micron range in an attempt to increase its surface area and consequently its dissolution rate and bioavailability. The effectiveness of nanocrystal drugs is evidenced by the fact that six FDA approved nanocrystal drugs are already on the market. The bioavailabilities of these preparations have been significantly improved compared to their conventional dosage forms. There are two main approaches for preparation of drug nanocrystals; these are the top-down and bottom-up techniques. Top-down techniques have been successfully used in both lab scale and commercial scale manufacture. Bottom-up approaches have not yet been used at a commercial level, however, these techniques have been found to produce narrow sized distribution nanocrystals using simple methods. Bottom-up techniques have been also used in combination with top-down processes to produce drug nanoparticles. The main aim of this review article is to discuss the various methods for nanosizing drugs to improve their bioavailabilities. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Synthesis and testing of nanosized zeolite Y

    Science.gov (United States)

    Karami, Davood

    This work focuses on the synthesis and testing of nanosized zeolite Y. The synthesis formulations of faujasite-type structure of zeolite Y prepared in nanosized form are described. The synthetic zeolite Y is the most widely employed for the preparation of fluid catalytic cracking (FCC) catalysts. The synthesis of zeolite Y is very complicated process. The mean particle size of zeolite Y is 1800 nm. The major challenge of this work involved reducing this average particle size to less than 500 nm. The preliminary experiments were conducted to obtain the pure zeolite Y using the soluble silicates as a silica source. This was achieved by applying the experimental design approach to study the effects of many parameters. The ageing time turned out to be the most significant variable affecting product purity. Based on the preliminary results, a detailed investigation was carried out to determine the effects of silica-alumina precursor preparations on zeolite Y synthesis. Aluminosilicate precursors were prepared by gelling and precipitation of soluble silicate. The as-prepared precursors were used for the hydrothermal synthesis of zeolite Y. The procedure of the precipitation of soluble silicate yielded pure zeolite Y at the conventional synthesis conditions. The extent of purity of zeolite Y depends on the surface areas of aluminosilicate precursors. A novel approach to zeolite Y synthesis was employed for the preparation of the pure nanosized zeolite Y. This was achieved by applying the method of impregnation of precipitated silica. This novel method of impregnation for zeolite Y preparation allows eliminating the vigorous agitation step required for the preparation of a homogeneous silica solution, thereby simplifying the synthesis of zeolite Y in one single vessel. In case of the synthesis of nanosized zeolite Y, the effect of varying the organic templates on the formation of nanosized particles of zeolite Y was investigated, while all other reaction parameters were

  4. Preparation of nanosized non-oxide powders using diatomaceous earth

    Directory of Open Access Journals (Sweden)

    Šaponjić A.

    2009-01-01

    Full Text Available In this paper the nanosized non-oxide powders were prepared by carbothermal reduction and subsequent nitridation of diatomaceous earth which is a waste product from coal exploitation. Our scope was to investigate the potential use of diatomaceous earth as a main precursor for low-cost nanosized non-oxide powder preparation as well as to solve an environmental problem. The influence of carbon materials (carbonized sucrose, carbon cryogel and carbon black as a reducing agent on synthesis and properties of low-cost nanosized nonoxide powders was also studied. The powders were characterized by specific surface area, X-ray and SEM investigations. It was found that by using diatomaceous earth it is was possible to produce either a mixture of non-oxide powders (Si3N4/SiC or pure SiC powders depending on temperature.

  5. Nanosized lithium titanates produced by plasma technique

    International Nuclear Information System (INIS)

    Grabis, J; Orlovs, A; Rasmane, Dz

    2007-01-01

    The synthesis of nanosized lithium titanates is studied by evaporation of coarse grained commercially available titanium and lithium carbonate particles in radio-frequency plasma flow with subsequent controlling formation and growth conditions of product particles. In accordance with the XRD analysis the phase composition of the obtained powders is determined by feeding rate of precursors and strongly by ratio of lithium and titanium. The Li 2 TiO 3 and Li 4 Ti 5 O 12 particles containing small amounts of extra phases were obtained at ratio of Li/Ti = 2 and Li/Ti = 0.8 respectively, feeding rate of precursors being in the range of 0.6-0.9 kg/h. Specific surface area of powders is in the range of 20-40 m2/g depending on concentration of vapours in gas flow and cooling rate of the products. Additional calcination of nanosize particles at 800-900 deg. C improves phase composition of lithium titanates

  6. Atomic scale modelling of nanosize Ni sub 3 Al cluster beam deposition on Al, Ni and Ni sub 3 Al (1 1 1) surfaces

    CERN Document Server

    Kharlamov, V S; Hou, M

    2002-01-01

    The slowing down of Ni sub 3 Al clusters on a Al, Ni and Ni sub 3 Al (1 1 1) surfaces is studied by atomic scale modelling. The semi-grand canonical metropolis Monte Carlo is used for the preparation of isolated clusters at thermodynamic equilibrium. The cluster deposition on the surface is studied in detail by classical Molecular Dynamics simulations that include a model to account for electron-phonon coupling. Long- and short-range orders in the cluster are evaluated as functions of temperature in an impact energy range between 0 and 1.5 eV/atom. The interaction between the Ni sub 3 Al cluster and an Al surface is characterised low short range (chemical) disorder. No sizeable epitaxy is found, subsequent to the impact. In contrast, in the case of Ni and Ni sub 3 Al substrates, which are harder materials than aluminium, the chemical disorder is higher and epitaxial accommodation is possible. With these substrates, chemical disorder in the cluster is an increasing function of the impact energy, as well as of ...

  7. Nanosize electropositive fibrous adsorbent

    Science.gov (United States)

    Tepper, Frederick; Kaledin, Leonid

    2005-01-04

    Aluminum hydroxide fibers approximately 2 nanometers in diameter and with surface areas ranging from 200 to 650 m.sup.2 /g have been fount to be highly electropositive. When dispersed in water they are able to attach to and retain electronegative particles. When combined into a composite filter with other fibers or particles they can filter bacteria and nano size particulates such as viruses and colloidal particles at high flux through the filter. Such filters can be used for purification and sterilization of water, biological, medical and pharmaceutical fluids, and as a collector/concentrator for detection and assay of mirobes and viruses. The alumina fibers are also capable of filtering sub-micron inorganic and metallic particles to produce ultra pure water. The fibers are suitable as a substrate for growth of cells. Macromolicules such as proteins may be separated from each other based on their electronegative charges.

  8. One pot synthesis of nanosized anion doped TiO2: Effect of irradiation of sound waves on surface morphology and optical properties

    Science.gov (United States)

    Sharotri, Nidhi; Sud, Dhiraj

    2015-08-01

    Commercialization of AOP's for remediation of pollutants from environmental matrix required the process to be operated by solar light. Semiconductor TiO2 has emerged as an effective and preferred photocatalyst in the field of environmental photocatalysis due to its; (i) biological and chemical inertness (ii) resistance to chemical and photo corrosion, (iii) can absorb natural UV light due to appropriate energetic separation between its valence and conduction band. However, unfortunately the optical band gap of TiO2 (3.0-3.23 eV) with absorption cut off ˜ 380 nm, enables it to harness only a small fraction (˜ 5%) of the entire solar spectrum. One of the current areas of research is modification of TiO2 photocatalyst. In present paper one pot greener synthesis from titanium isopropoxide and hydroxylamine hydrochloride has been used as titanium and nitrogen precursor under ultrasonic waves. The as synthesized TiO2 nanomaterials were dried at 100°C and further calcinated at different temperatures. The effect of reaction parameters such as ultrasonication time on the yield, surface morphology, spectroscopic data and optical properties was also investigated. The results confirm that the anatase phase is a main phase with a crystallite size of 35-77 nm and the calculated band gap of nanomaterials varies from 2.10-3.1 eV.

  9. One pot synthesis of nanosized anion doped TiO2: Effect of irradiation of sound waves on surface morphology and optical properties

    International Nuclear Information System (INIS)

    Sharotri, Nidhi; Sud, Dhiraj

    2015-01-01

    Commercialization of AOP’s for remediation of pollutants from environmental matrix required the process to be operated by solar light. Semiconductor TiO 2 has emerged as an effective and preferred photocatalyst in the field of environmental photocatalysis due to its; (i) biological and chemical inertness (ii) resistance to chemical and photo corrosion, (iii) can absorb natural UV light due to appropriate energetic separation between its valence and conduction band. However, unfortunately the optical band gap of TiO 2 (3.0-3.23 eV) with absorption cut off ∼ 380 nm, enables it to harness only a small fraction (∼ 5%) of the entire solar spectrum. One of the current areas of research is modification of TiO 2 photocatalyst. In present paper one pot greener synthesis from titanium isopropoxide and hydroxylamine hydrochloride has been used as titanium and nitrogen precursor under ultrasonic waves. The as synthesized TiO 2 nanomaterials were dried at 100°C and further calcinated at different temperatures. The effect of reaction parameters such as ultrasonication time on the yield, surface morphology, spectroscopic data and optical properties was also investigated. The results confirm that the anatase phase is a main phase with a crystallite size of 35-77 nm and the calculated band gap of nanomaterials varies from 2.10-3.1 eV

  10. Strong enhancement of superconductivity in a nanosized Pb bridge

    OpenAIRE

    Misko, V. R.; Fomin, V. M.; Devreese, J. T.

    2000-01-01

    In recent experiments with a superconducting nanosized Pb bridge formed between a scanning tunneling microscope tip and a substrate, superconductivity has been detected at magnetic fields, which are few times larger than the third (surface) critical field. We describe the observed phenomenon on the basis of a numerical solution of the Ginzburg-Landau equations in a model structure consisting of six conoids. The spatial distribution of the superconducting phase is shown to be strongly inhomoge...

  11. Vapor-phase photo-oxidation of methanol over nano-size titanium dioxide clusters dispersed in MCM-41 host material part 2: catalytic properties and surface transient species.

    Science.gov (United States)

    Bhattacharyya, K; Varma, S; Kumar, D; Tripathi, A K; Gupta, N M

    2005-05-01

    We report in this paper on the ultraviolet-assisted vapor-phase oxidation of methanol at room temperature, with the help of nano-size clusters of titanium dioxide dispersed in an MCM-41 silicate matrix. The surface species formed during the adsorption/oxidation of methanol and the transformation that they undergo as a result of ultraviolet irradiation were monitored using in-situ Fourier transform infrared and thermal desorption spectroscopy techniques. Parallel experiments conducted on TiO2/MCM, bulk titania, and pristine MCM-41 samples helped in identifying the individual role of titanium dioxide and host matrix in these processes. The photo-catalytic oxidation of methanol, at concentrations of 0.1 to 1.1 mol% in air, gave rise to formation of CO2 and H2O as products, for both the TiO2/MCM and bulk TiO2 samples. No such reaction occurred on titania-free MCM. Furthermore, the rate of reaction depended upon the TiO2 content of a sample and also on the concentration of methanol in reaction mixture. Thus, the rate of conversion increased progressively with the increase in TiO2 loading from 5 to 21 wt% in TiO2/MCM samples, particularly for the experiments with high concentration of methanol. For low methanol concentration (0.1 mol%) in air, the effect of titania content in MCM was very small. The specific activity (per g of titania) of a sample, on the other hand, showed an inverse relationship with the loading of titanium dioxide in a sample. Infrared and temperature-programmed desorption results revealed that the mode of CH3OH adsorption and the reactivity of the transient species formed during the oxidation process were independent of the size of dispersed titania particles. Thus, the particles of approximately 2-6 nm size, present in TiO2/MCM, exhibited a chemisorption behavior similar to that of the bulk titania. The results of the present study provide strong evidence that the hydroxyl groups, both on the host matrix and at the titania sites, participate

  12. Synthesis and characterization of nanosize sodium titanates

    Energy Technology Data Exchange (ETDEWEB)

    Elvington, M. C.; Tosten, M.; Taylor-Pashow, K. M. L.; Hobbs, D. T., E-mail: david.hobbs@srnl.doe.gov [Savannah River National Laboratory (United States)

    2012-11-15

    This paper describes the synthesis and peroxide-modification of nanosize monosodium titanate (nMST). The synthesis method was derived from a sol-gel process used to produce micron-sized monosodium titanate (MST). Key modifications to this process include altering reagent concentrations, omitting a particle seed step, and introducing a non-ionic surfactant to facilitate control of particle formation and growth. The nMST material exhibits spherical-shaped particle morphology with a monodisperse distribution of particle diameters in the range from 100 to 150 nm. The BET surface area and isoelectric point of the nMST measured 285 m{sup 2} g{sup -1} and 3.34 pH units, respectively, which is more than an order of magnitude higher in surface area and a pH unit lower than that measured for the microsize MST. The nMST material serves as an effective ion exchanger under both weakly acidic and strongly alkaline conditions and was converted to a peroxotitanate form by reaction with hydrogen peroxide.

  13. Nanosized Selenium: A Novel Platform Technology to Prevent Bacterial Infections

    Science.gov (United States)

    Wang, Qi

    As an important category of bacterial infections, healthcare-associated infections (HAIs) are considered an increasing threat to the safety and health of patients worldwide. HAIs lead to extended hospital stays, contribute to increased medical costs, and are a significant cause of morbidity and mortality. In the United States, infections encountered in the hospital or a health care facility affect more than 1.7 million patients, cost 35.7 billion to 45 billion, and contribute to 88,000 deaths in hospitals annually. The most conventional and widely accepted method to fight against bacterial infections is using antibiotics. However, because of the widespread and sometimes inappropriate use of antibiotics, many strains of bacteria have rapidly developed antibiotic resistance. Those new, stronger bacteria pose serious, worldwide threats to public health and welfare. In 2014, the World Health Organization (WHO) reported antibiotic resistance as a global serious threat that is no longer a prediction for the future but is now reality. It has the potential to affect anyone, of any age, in any country. The most effective strategy to prevent antibiotic resistance is minimizing the use of antibiotics. In recent years, nanomaterials have been investigated as one of the potential substitutes of antibiotics. As a result of their vastly increased ratio of surface area to volume, nanomaterials will likely exert a stronger interaction with bacteria which may affect bacterial growth and propagation. A major concern of most existing antibacterial nanomaterials, like silver nanoparticles, is their potential toxicity. But selenium is a non-metallic material and a required nutrition for the human body, which is recommended by the FDA at a 53 to 60 μg daily intake. Nanosized selenium is considered to be healthier and less toxic compared with many metal-based nanomaterials due to the generation of reactive oxygen species from metals, especially heavy metals. Therefore, the objectives of

  14. Characterisation and Treatment of Nano-sized Particles, Colloids and Associated Polycyclic Aromatic Hydrocarbons in Stormwater

    DEFF Research Database (Denmark)

    Nielsen, Katrine

    . The associated pollutants will, if not removed in stormwater treatment facilities, be discharged into receiving surface waters, due to enhanced transportation exerted by the colloids and nano-sized particles. More stormwater than previously is separated from wastewater and drained to stormwater treatment.......Since little is known about the colloids and nano-sized particle-enhanced transportation of pollutants in stormwater, it has been difficult to determine their quantitative role in the total release of pollutants into receiving waters.Therefore the main purpose of this thesis has been to document the presence...... and size distribution of colloids and nano-sized particles in stormwater, as well as quantify the particle-enhanced transportation of polycyclic aromatic hydrocarbons (PAHs) in stormwater. Stormwater from five sites in Europe was collected to characterise the particulate matter, colloids and nano...

  15. Nano-Sized Zero Valent Iron and Covalent Organic Polymer Composites for Azo Dye Remediation

    DEFF Research Database (Denmark)

    Mines, Paul D.; Byun, Jeehye; Hwang, Yuhoon

    2014-01-01

    Having superior reductive properties and large surface areas, nanosized zero valent iron (nZVI) is ideal for the degradation of chemicals such as azo dyes and trichloroethylene (TCE). However, immobilization of nZVI is a key parameter in its effectiveness as a chemical degradation agent. In this ...

  16. Low temperature solvothermal synthesis of nanosized NiSb as a Li-ion battery anode material

    International Nuclear Information System (INIS)

    Xie, J.; Zhao, X.B.; Yu, H.M.; Qi, H.; Cao, G.S.; Tu, J.P.

    2007-01-01

    Nanosized intermetallic compound NiSb was successfully synthesized by a solvothermal route and studied as a promising anode material for secondary lithium-ion batteries. The as-prepared NiSb powder was characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and field emission scanning electron microscope (FESEM). The electrochemical performance of the nanosized NiSb electrode was investigated by constant current charge and discharge cycling and electrochemical impedance spectroscopy (EIS). It was found that the nanosized NiSb shows a higher initial capacity compared to microsized one prepared by a levitation-melting/ball-milling route due to larger specific surface area of the nanomaterial. The nanosized NiSb shows a rapid capacity fade due to the pulverization and exfoliation of active material caused by severe electrochemical grinding upon long-term cycling

  17. Anti-friction properties of thin layered nanosized protective films “Epilam”: synergy effect

    International Nuclear Information System (INIS)

    Vokhidov, A S

    2017-01-01

    In the general concept of temperature-resistant antifriction coatings, greate attention is paid to the growing use of multifunctional films. Epilams are polymer compositions, studying organic chemistry, namely to compositions (liquids), which, when applied to a solid surface, form on it nanosize multifunctional molecular film of a certain way of oriented molecules of surface-active agents (surfactants, SAA), which significantly changes the surface energy of the base (substrate). (paper)

  18. Anti-friction properties of thin layered nanosized protective films “Epilam”: synergy effect

    Science.gov (United States)

    Vokhidov, A. S.

    2017-05-01

    In the general concept of temperature-resistant antifriction coatings, greate attention is paid to the growing use of multifunctional films. Epilams are polymer compositions, studying organic chemistry, namely to compositions (liquids), which, when applied to a solid surface, form on it nanosize multifunctional molecular film of a certain way of oriented molecules of surface-active agents (surfactants, SAA), which significantly changes the surface energy of the base (substrate).

  19. Evaluation of Extrusion Technique for Nanosizing Liposomes

    Directory of Open Access Journals (Sweden)

    Sandy Gim Ming Ong

    2016-12-01

    Full Text Available The aim of the present study was to study the efficiency of different techniques used for nanosizing liposomes. Further, the aim was also to evaluate the effect of process parameters of extrusion techniques used for nanosizing liposomes on the size and size distribution of the resultant liposomes. To compare the efficiency of different nanosizing techniques, the following techniques were used to nanosize the liposomes: extrusion, ultrasonication, freeze-thaw sonication (FTS, sonication and homogenization. The extrusion technique was found to be the most efficient, followed by FTS, ultrasonication, sonication and homogenization. The extruder used in the present study was fabricated using readily available and relatively inexpensive apparatus. Process parameters were varied in extrusion technique to study their effect on the size and size distribution of extruded liposomes. The results obtained indicated that increase in the flow rate of the extrusion process decreased the size of extruded liposomes however the size homogeneity was negatively impacted. Furthermore, the liposome size and distribution was found to decline with decreasing membrane pore size. It was found that by extruding through a filter with a pore size of 0.2 µm and above, the liposomes produced were smaller than the pore size, whereas, when they were extruded through a filter with a pore size of less than 0.2 µm the resultant liposomes were slightly bigger than the nominal pore size. Besides that, increment of extrusion temperature above transition temperature of the pro-liposome had no effect on the size and size distribution of the extruded liposomes. In conclusion, the extrusion technique was reproducible and effective among all the methods evaluated. Furthermore, processing parameters used in extrusion technique would affect the size and size distribution of liposomes. Therefore, the process parameters need to be optimized to obtain a desirable size range and homogeneity

  20. Nanosized Building Blocks for Customizing Novel Antibiofilm Approaches.

    Science.gov (United States)

    Paula, A J; Koo, H

    2017-02-01

    Recent advances in nanotechnology provide unparalleled flexibility to control the composition, size, shape, surface chemistry, and functionality of materials. Currently available engineering approaches allow precise synthesis of nanocompounds (e.g., nanoparticles, nanostructures, nanocrystals) with both top-down and bottom-up design principles at the submicron level. In this context, these "nanoelements" (NEs) or "nanosized building blocks" can 1) generate new nanocomposites with antibiofilm properties or 2) be used to coat existing surfaces (e.g., teeth) and exogenously introduced surfaces (e.g., restorative or implant materials) for prevention of bacterial adhesion and biofilm formation. Furthermore, functionalized NEs 3) can be conceived as nanoparticles to carry and selectively release antimicrobial agents after attachment or within oral biofilms, resulting in their disruption. The latter mechanism includes "smart release" of agents when triggered by pathogenic microenvironments (e.g., acidic pH or low oxygen levels) for localized and controlled drug delivery to simultaneously kill bacteria and dismantle the biofilm matrix. Here we discuss inorganic, metallic, polymeric, and carbon-based NEs for their outstanding chemical flexibility, stability, and antibiofilm properties manifested when converted into bioactive materials, assembled on-site or delivered at biofilm-surface interfaces. Details are provided on the emerging concept of the rational design of NEs and recent technological breakthroughs for the development of a new generation of nanocoatings or functional nanoparticles for biofilm control in the oral cavity.

  1. Effects of nanosized constriction on thermal transport properties of graphene

    Science.gov (United States)

    2014-01-01

    Thermal transport properties of graphene with nanosized constrictions are investigated using nonequilibrium molecular dynamics simulations. The results show that the nanosized constrictions have a significant influence on the thermal transport properties of graphene. The thermal resistance of the nanosized constrictions is on the order of 107 to 109 K/W at 150 K, which reduces the thermal conductivity by 7.7% to 90.4%. It is also found that the constriction resistance is inversely proportional to the width of the constriction and independent of the heat current. Moreover, we developed an analytical model for the ballistic thermal resistance of the nanosized constrictions in two-dimensional nanosystems. The theoretical prediction agrees well with the simulation results in this paper, which suggests that the thermal transport across the nanosized constrictions in two-dimensional nanosystems is ballistic in nature. PACS 65.80.CK; 61.48.Gh; 63.20.kp; 31.15.xv PMID:25232292

  2. Mechanical properties of dental composite materials reinforced with micro and nano-size Al2O3 filler particles

    International Nuclear Information System (INIS)

    Foroutan, F.; Javadpour, J.; Khavandi, A.; Atai, M.

    2011-01-01

    Composite specimens were prepared by dispersion of various amounts of nano-sized Al 2 O 3 fillers in a monomer system containing 60 p ercent B is-GMA and 40 p ercent T EGDMA. For comparative purposes, composite samples containing micrometer size Al 2 O 3 fillers were also prepared following the same procedure. The mechanical properties of the light- cured samples were assessed by three-point flexural strength, diametral tensile strength, and microhardness tests. The results indicated a more than hundred percent increase in the flexural strength and nearly an eighty percent increase in the diametral tensile strength values in the samples containing nano-size Al 2 O 3 filler particles. It is interesting to note that, this improvement was observed at a much lower nano-size filler content. Fracture surfaces analyzed by scanning electron microscopy, indicated a brittle type of fracture in both sets of specimens.

  3. Hybrid composites of nano-sized zero valent iron and covalent organic polymers for groundwater contaminant degradation

    DEFF Research Database (Denmark)

    Mines, Paul D.; Byun, J.; Hwang, Yuhoon

    Zero valent iron is commonly used in a variety of treatment technologies (e.g. permeable reactive barriers), though recently a heavier focus has been placed on nano-sized zero valent iron (nZVI). Having superior reductive properties and large surface areas, nZVI is ideal for the degradation of ch...

  4. Bimetallic nickel-cobalt nanosized layers supported on polar ZnO surfaces: metal-support interaction and alloy effects studied by synchrotron radiation X-ray photoelectron spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Law, Y.T.; Skála, T.; Pis, I.; Nehasil, V.; Vondráček, Martin; Zafeiratos, S.

    2012-01-01

    Roč. 116, č. 18 (2012), s. 10048-10056 ISSN 1932-7447 R&D Projects: GA MŠk(CZ) LC06058; GA ČR GD202/09/H041 Institutional support: RVO:68378271 Keywords : mc fuel-cell * hydrogen -production * oxide surfaces Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 4.814, year: 2012

  5. Synthesis, characterization and properties of nano-sized transition metal oxides

    Science.gov (United States)

    Yin, Ming

    2005-12-01

    Chapter 1. A General introduction to the emerging field of nanomaterials is presented highlighting the category of transition metal oxides. The wide variety of structures, properties, and phenomena of transition metal oxides are stressed. Nano-sized transition metal oxides are presented as systems for fundamental and application research. Examples of individual transition metal oxides are provided. Important developments in the synthesis and characterization of nano-sized transition metal oxides that have contributed to this work are reviewed. A novel synthesis (TDMA) is developed and successfully applied to the synthesis of transition metal oxide nanocrystals. Chapter 2. The synthesis of monodisperse cubic wuestite FexO nanocrystals is presented. The influence of reaction temperature and the molar ratio of surfactant to iron precursor was investigated, in order to further understand the ability to control particle size and monodispersity. In contrast to bulk material, it is also found that the nano-sized ligand-capped wuestite FexO particles were stable at room temperature. The procedure enable the collection of highly monodisperse nanocrystals of variable and uniform diameters as a function of time. Sharp Hancock analysis indicates that the reaction proceeds by a diffusion limited mechanism. Routes to control the size of gamma-Fe2O3 nanocrystals are also presented. gamma-Fe2O3 nanocrystals from 6 nm to 12 nm in diameter with uniform size, shape, consistent crystal structure were prepared. Chapter 3. A simple reaction to prepare monodisperse MnO nanocrystals is presented. MnO nanocrystals was prepared by thermal decomposition of manganese acetate in the presence of oleic acid at high temperature and by following annealing. Particles with different sizes and shapes were obtained by controlling annealing time. The morphology of MnO nanocrystals was studied based on their crystal structure and surface energy. SQUID measurement shows ferromagnetic magnetism at low

  6. Infrared absorption spectra of nanosized silica with organic additives

    Directory of Open Access Journals (Sweden)

    Мaria О. Savchenko

    2014-12-01

    Full Text Available The prospects of using of silica nanoparticles modified with urea-formaldehyde polymers which is obtained by sulfuric acid sol-gel technology are shown. The aim is a detailed research on the infrared absorption spectra of nanodispersed silica modified with urea-formaldehyde polymers with identification of the absorption bands of the spectrum. The method of infrared spectroscopy is used to research spectral characteristics of nanosized silica, urea-formaldehyde polymer and nanodispersed silica modified with urea-formaldehyde polymers in different ratio. It is found that interaction of initial ingredients occurs at the stage of phase formation in solutions in colloidal silica products containing urea-formaldehyde polymers. Organic components are localized on the surface of the globules and in the interglobular space. This result of such interaction is the physical and structural transformation of globular surfaces of silica and new chemical compounds formation. This allows to give to final product a variety of properties required for practical use in many industries.

  7. Tribological properties of nanosized calcium carbonate filled polyamide 66 nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Itagaki, Kaito [Department of Mechanical Engineering, Graduate School of Engineering, Kogakuin University, 2665-1 Nakano, Hachioji, Tokyo 192-0015 Japan (Japan); Nishitani, Yosuke [Department of Mechanical Engineering, Faculty of Engineering, Kogakuin University, 2665-1 Nakano, Hachioji, Tokyo, 192-0015 Japan (Japan); Kitano, Takeshi [Polymer Centre, Faculty of Technology, Tomas Bata University in Zlin, T.G.M. 275, Zlin, 767 72 Czech Republic (Czech Republic); Eguchi, Kenichiro [Shiraishi Central Laboratories, 4-78 Motohama,Amagasaki,Hyogo,660-0085 Japan (Japan)

    2016-03-09

    For the purpose of developing high performance tribomaterials for mechanical sliding parts such as gears, bearings and so on, nanosized calcium carbonate (nano-CaCO{sub 3}) filled polyamide 66 (PA66) nanocomposites were investigated. The nano-CaCO{sub 3} was a kind of precipitated (colloid typed) CaCO{sub 3}, and its average particle size was 40, 80 and 150 nm. Surface treatment was performed by fatty acid on the nano-CaCO{sub 3} and its volume fraction in the nanocomposite was varied from 1 to 20vol.%. These nanocomposites were melt-mixed by a twin screw extruder and injection-molded. Tribological properties were measured by two types of sliding wear testers such as ring-on-plate type and ball-on-plate type one under dry condition. The counterface, worn surface and wear debris were observed by digital microscope and scanning electron microscope. It was found that the nano-CaCO{sub 3} has a good effect on the tribological properties, although the effect on the frictional coefficient and specific wear rate is differed by the volume fraction and the type of sliding wear modes. This is attributed to the change of wear mechanisms, which is the change of form of the transfer films on the counterface and the size of wear debris. It follows from these results that PA66/nano-CaCO{sub 3} nanocomposites may be possible to be the high performance tribomaterials.

  8. Nano-sized manganese oxides as biomimetic catalysts for water oxidation in artificial photosynthesis: a review.

    Science.gov (United States)

    Najafpour, Mohammad Mahdi; Rahimi, Fahimeh; Aro, Eva-Mari; Lee, Choon-Hwan; Allakhverdiev, Suleyman I

    2012-10-07

    There has been a tremendous surge in research on the synthesis of various metal compounds aimed at simulating the water-oxidizing complex (WOC) of photosystem II (PSII). This is crucial because the water oxidation half reaction is overwhelmingly rate-limiting and needs high over-voltage (approx. 1 V), which results in low conversion efficiencies when working at current densities required for hydrogen production via water splitting. Particular attention has been given to the manganese compounds not only because manganese has been used by nature to oxidize water but also because manganese is cheap and environmentally friendly. The manganese-calcium cluster in PSII has a dimension of about approximately 0.5 nm. Thus, nano-sized manganese compounds might be good structural and functional models for the cluster. As in the nanometre-size of the synthetic models, most of the active sites are at the surface, these compounds could be more efficient catalysts than micrometre (or bigger) particles. In this paper, we focus on nano-sized manganese oxides as functional and structural models of the WOC of PSII for hydrogen production via water splitting and review nano-sized manganese oxides used in water oxidation by some research groups.

  9. Nano-sized manganese oxides as biomimetic catalysts for water oxidation in artificial photosynthesis: a review

    Science.gov (United States)

    Najafpour, Mohammad Mahdi; Rahimi, Fahimeh; Aro, Eva-Mari; Lee, Choon-Hwan; Allakhverdiev, Suleyman I.

    2012-01-01

    There has been a tremendous surge in research on the synthesis of various metal compounds aimed at simulating the water-oxidizing complex (WOC) of photosystem II (PSII). This is crucial because the water oxidation half reaction is overwhelmingly rate-limiting and needs high over-voltage (approx. 1 V), which results in low conversion efficiencies when working at current densities required for hydrogen production via water splitting. Particular attention has been given to the manganese compounds not only because manganese has been used by nature to oxidize water but also because manganese is cheap and environmentally friendly. The manganese–calcium cluster in PSII has a dimension of about approximately 0.5 nm. Thus, nano-sized manganese compounds might be good structural and functional models for the cluster. As in the nanometre-size of the synthetic models, most of the active sites are at the surface, these compounds could be more efficient catalysts than micrometre (or bigger) particles. In this paper, we focus on nano-sized manganese oxides as functional and structural models of the WOC of PSII for hydrogen production via water splitting and review nano-sized manganese oxides used in water oxidation by some research groups. PMID:22809849

  10. One-pot synthesis of silanol-free nanosized MFI zeolite

    Science.gov (United States)

    Grand, Julien; Talapaneni, Siddulu Naidu; Vicente, Aurélie; Fernandez, Christian; Dib, Eddy; Aleksandrov, Hristiyan A.; Vayssilov, Georgi N.; Retoux, Richard; Boullay, Philippe; Gilson, Jean-Pierre; Valtchev, Valentin; Mintova, Svetlana

    2017-10-01

    The synthesis of nanostructured zeolites enables modification of catalytically relevant properties such as effective surface area and diffusion path length. Nanostructured zeolites may be synthesized either in alkaline media, and so contain significant numbers of hydrophilic silanol groups, or in expensive and harmful fluoride-containing media. Here, we report and characterize, using a combination of experimental and theoretical techniques, the one-pot synthesis of silanol-free nanosized MFI-type zeolites by introducing atomically dispersed tungsten; this prevents silanol group occurrence by forming flexible W-O-Si bridges. These W-O-Si bonds are more stable than Si-O-Si in the all-silica MFI zeolite. Tungsten incorporation in nanosized MFI crystals also modifies other properties such as structural features, hydrophobicity and Lewis acidity. The effect of these is illustrated on the catalytic epoxidation of styrene and separation of CO2 and NO2. Silanol-free nanosized W-MFI zeolites open new perspectives for catalytic and separation applications.

  11. Mechanical properties of dental resin composites by co-filling diatomite and nanosized silica particles

    International Nuclear Information System (INIS)

    Wang Hua; Zhu Meifang; Li Yaogang; Zhang Qinghong; Wang Hongzhi

    2011-01-01

    The aim of this study was to investigate the mechanical property effects of co-filling dental resin composites with porous diatomite and nanosized silica particles (OX-50). The purification of raw diatomite by acid-leaching was conducted in a hot 5 M HCl solution at 80 deg. C for 12 h. Both diatomite and nanosized SiO 2 were silanized with 3-methacryloxypropyltrimethoxysilane. The silanized inorganic particles were mixed into a dimethacrylate resin. Purified diatomite was characterized by X-ray diffraction, UV-vis diffuse reflectance spectroscopy and an N 2 adsorption-desorption isotherm. Silanized inorganic particles were characterized using Fourier transform infrared spectroscopy and a thermogravimetric analysis. The mechanical properties of the composites were tested by three-point bending, compression and Vicker's microhardness. Scanning electron microscopy was used to show the cross-section morphologies of the composites. Silanization of diatomite and nanosized silica positively reinforced interactions between the resin matrix and the inorganic particles. The mechanical properties of the resin composites gradually increased with the addition of modified diatomite (m-diatomite). The fracture surfaces of the composites exhibited large fracture steps with the addition of m-diatomite. However, when the mass fraction of m-diatomite was greater than 21 wt.% with respect to modified nanosized silica (mOX-50) and constituted 70% of the resin composite by weight, the mechanical properties of the resin composites started to decline. Thus, the porous structure of diatomite appears to be a crucial factor to improve mechanical properties of resin composites.

  12. Synthesis of Nanosize Yttria-Stabilized Zirconia by a Molecular Decomposition Process

    Science.gov (United States)

    Jiang, Yi; Bhide, Sanjeevani V.; Virkar, Anil V.

    2001-02-01

    Nanosize yttria-stabilized zirconia (YSZ) was synthesized by a novel approach based on molecular decomposition. In this approach, yttria-doped BaZrO3 (Y-BaZrO3) or yttria-doped Na2ZrO3 (Y-Na2ZrO3) precursors were first synthesized from BaCO3, ZrO2, and Y2O3 or BaCO3 and commercial YSZ for Y-BaZrO3, and from Na2CO3 and YSZ for Y-Na2ZrO3, by a conventional solid-state reaction method. The precursors were then boiled to leach away the unwanted species, BaO or Na2O, either in a dilute HNO3 solution in water in the case of Y-BaZrO3, or in deionized water in the case of Y-Na2ZrO3. During boiling in HNO3 or water, the residue of Zr-Y-O skeleton formed fine, nanosize YSZ particles. The particle size of the as-synthesized nanosize powders estimated from X-ray diffraction peak broadening was ∼2-3 nm, while that estimated from specific surface area measurements by BET adsorption isotherm was ∼15 nm. Examination under a transmission electron microscope showed that the crystallite size was ∼5 nm. Samples were also examined by Raman spectroscopy to determine the crystallographic polymorph of the YSZ formed. Subsequent heating in air led to particle growth. However, even when the particles were heated to a temperature as high as 1000°C, the particle size was well in the nanosize range.

  13. Synthesis of beta carbon nitride nanosized crystal through mechanochemical reaction

    CERN Document Server

    Yin Long Wei; Liu Yu Xian; Sui Jin Ling; Wang Jing Min

    2003-01-01

    Nanosized beta carbon nitride (beta-C sub 3 N sub 4), of grain size several tens of nanometres, has been synthesized by mechanochemical reaction processing. The low-cost synthetic method developed facilitates the novel and effective synthesis of nanosized crystalline beta-C sub 3 N sub 4 (a = 6.36 A, c = 4.648 A) powders. The graphite powders were first milled to a nanoscale state, then the nanosized graphite powders were milled in an atmosphere of NH sub 3 gas. It was found that nanosized beta-C sub 3 N sub 4 was formed after high-energy ball milling under an NH sub 3 atmosphere. After thermal annealing, the shape of the beta-C sub 3 N sub 4 changes from flake-like to sphere-like. The nanosized beta-C sub 3 N sub 4 formed was characterized by x-ray diffraction, Fourier transformation infrared spectroscopy, and transmission electron microscopy. A solid-gas reaction mechanism was proposed for the formation of nanosized beta-C sub 3 N sub 4 at room temperature induced by mechanochemical activation.

  14. Strong enhancement of superconductivity in a nanosized Pb bridge

    Science.gov (United States)

    Misko, V. R.; Fomin, V. M.; Devreese, J. T.

    2001-07-01

    In recent experiments with a superconducting nanosized Pb bridge formed between a scanning tunneling microscope tip and a substrate, superconductivity has been detected at magnetic fields, that are a few times larger than the third (surface) critical field. We describe the observed phenomenon on the basis of a numerical solution of the Ginzburg-Landau equations in a model structure consisting of six conoids. The spatial distribution of the superconducting phase is shown to be strongly inhomogeneous, with a concentration of the superconducting phase near the narrowest part (the ``neck'') of the bridge. We show that suppression of superconductivity in the bridge by applied magnetic field or by temperature first occurs near the bases and then in the neck region, what leads to a continuous superconducting-to-normal resistive transition. A position of the transition midpoint depends on temperature and, typically, is by one order of magnitude higher than the second critical field Hc2. We find that the vortex states can be realized in the bridge at low temperatures T/Tc<=0.6. The vortex states lead to a fine structure of the superconducting-to-normal resistive transition. We also analyze vortex states in the bridge that are characterized by a varying vorticity as a function of the bridge's height.

  15. Space-confined preparation of high surface area tungsten oxide and tungsten nitride inside the pores of mesoporous silica SBA-15

    DEFF Research Database (Denmark)

    Meyer, Simon; Beyer, Hans; Köhler, Klaus

    2015-01-01

    For the direct preparation of high surface area nitride materials, a lack of suitable precursors exists. Indirect preparation by gas phase nitridation (e.g. by ammonia) requires high temperatures and often results in sintering. The present work demonstrates that the space-confined preparation of W2......N inside the pores of ordered mesoporous silica SBA-15 offers a possibility to reduce sintering phenomena and thus to obtain smaller particles, porous structures and a higher surface area material. The preparation was pursued in a two-step approach. First, WO3 was introduced into the channels of SBA......-15 and second, ammonolysis was conducted for its conversion to W2N. When performed in the presence of the exo-template, SBA-15 acts as a stabilizer and small W2N particles (6-7 nm) with a high specific surface area (40 m(2) g(-1)) are obtained after template removal. When the template is, however...

  16. Local Electronic And Dielectric Properties at Nanosized Interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Bonnell, Dawn A. [Univ. of Pennsylvania, Philadelphia, PA (United States)

    2015-02-23

    Final Report to the Department of Energy for period 6/1/2000 to 11/30/2014 for Grant # DE-FG02-00ER45813-A000 to the University of Pennsylvania Local Electronic And Dielectric Properties at Nanosized Interfaces PI: Dawn Bonnell The behavior of grain boundaries and interfaces has been a focus of fundamental research for decades because variations of structure and composition at interfaces dictate mechanical, electrical, optical and dielectric properties in solids. Similarly, the consequence of atomic and electronic structures of surfaces to chemical and physical interactions are critical due to their implications to catalysis and device fabrication. Increasing fundamental understanding of surfaces and interfaces has materially advanced technologies that directly bear on energy considerations. Currently, exciting developments in materials processing are enabling creative new electrical, optical and chemical device configurations. Controlled synthesis of nanoparticles, semiconducting nanowires and nanorods, optical quantum dots, etc. along with a range of strategies for assembling and patterning nanostructures portend the viability of new devices that have the potential to significantly impact the energy landscape. As devices become smaller the impact of interfaces and surfaces grows geometrically. As with other nanoscale phenomena, small interfaces do not exhibit the same properties as do large interfaces. The size dependence of interface properties had not been explored and understanding at the most fundamental level is necessary to the advancement of nanostructured devices. An equally important factor in the behavior of interfaces in devices is the ability to examine the interfaces under realistic conditions. For example, interfaces and boundaries dictate the behavior of oxide fuel cells which operate at extremely high temperatures in dynamic high pressure chemical environments. These conditions preclude the characterization of local properties during fuel cell

  17. Pulsed laser-induced micro-and nanosized morphology and composition of titanium dental implants

    Science.gov (United States)

    Joób-Fancsaly, Á.; Divinyi, T.; Fazekas, Á.; Daroczi, Cs; Karacs, A.; Petõ, G.

    2002-10-01

    The surface morphology of machined screw-shaped titanium dental implants was modified by pulsed irradiation with an Nd glass laser. This method supplied very different surface elements in nanometer and micrometer ranges identified with scanning electron microscopy and atomic force microscopy as well. The surface composition was unchanged during these treatments. A rabbit experiment was carried out to investigate the direct bone contact (osseointegration) which was characterized by the removal torque of the implants. The 50 nm and 10-50 µm sized droplike elements were formed from the machined flat surface by the laser irradiation depending on the laser intensity. The osseointegration was enhanced by the increase of the density of nanosized elements and by the size of the microsized elements, showing the importance of this surface morphology in the direct bone-implant contact.

  18. Preparation and performance of nanosized tungsten carbides for electrocatalysis

    International Nuclear Information System (INIS)

    Shen Peikang; Yin Shibin; Li Zihui; Chen Chan

    2010-01-01

    The principle of the intermittent microwave heating (IMH) method and the details on the working procedure for prepare nanosized materials were presented along with the comparison to the traditional continuous microwave heating (CMH) method. The nanosized tungsten carbides were synthesized as an example by this novel method. It produced WC with the average particle size of 21.4 nm at the procedure of 15 s-on and 15 s-off for 20 times, however, the particle size increased to 35.7 nm by CMH method for 5 min. The pure WC was obtained by post-treating the sample in NaOH solution, which gave the better performance as support. The nanosized WC was used as support for the Pt nanoparticles (Pt-WC/C(IMH)) for alcohol oxidation and oxygen reduction. It was proved that the Pt-WC/C(IMH) electrocatalysts gave the better performance than that prepared by CMH method (Pt-WC/C(CMH)) or Pt/C electrocatalysts in terms of the activity and CO-tolerance. The intermittent microwave heating method is easier to scale-up for mass production of the nanosized tungsten carbides and other nanosized materials as well.

  19. Structure of extremely nanosized and confined In-O species in ordered porous materials

    International Nuclear Information System (INIS)

    Ramallo-Lopez, J.M.; Renteria, M.; Miro, E.E.; Requejo, F.G.; Traverse, A.

    2003-01-01

    Perturbed-angular correlation, x-ray absorption, and small-angle x-ray scattering spectroscopies were suitably combined to elucidate the local structure of highly diluted and dispersed InO x species confined in the porous of the ZSM5 zeolite. This novel approach allow us to determined the structure of extremely nanosized In-O species exchanged inside the 10-atom-ring channel of the zeolite, and to quantify the amount of In 2 O 3 crystallites deposited onto the external zeolite surface

  20. Characteristics of nano-sized yttria powder synthesized by a polyvinyl alcohol solution route at low temperature.

    Science.gov (United States)

    Lee, Sang-Jin; Jung, Choong-Hwan

    2012-01-01

    Nano-sized yttria (Y2O3) powders were successfully synthesized at a low temperature of 400 degrees C by a simple polymer solution route. PVA polymer, as an organic carrier, contributed to an atom-scale homogeneous precursor gel and it resulted in fully crystallized, nano-sized yttria powder with high specific surface area through the low temperature calcination. In this process, the content of PVA, calcination temperature and heating time affected the microstructure and crystallization behavior of the powders. The development of crystalline phase and the final particle size were strongly dependant on the oxidation reaction from the polymer burn-out step and the PVA content. In this paper, the PVA solution technique for the fabrication of nano-sized yttria powders is introduced. The effects of PVA content and holding time on the powder morphology and powder specific surface area are also studied. The characterization of the synthesized powders is examined by using XRD, DTA/TG, SEM, TEM and nitrogen gas adsorption. The yttria powder synthesized from the PVA content of 3:1 ratio and calcined at 400 degrees C had a crystallite size of about 20 nm or less with a high surface areas of 93.95-120.76 m2 g(-1).

  1. Mn3O4 nano-sized crystals: Rapid synthesis and extension to ...

    Indian Academy of Sciences (India)

    to preparation of nanosized LiMn2O4 materials. XIAO-LING CUI ... applications such as magnetic storage media, catalysis, electrodes, ion .... of ethanol. After similar processes with the rapid prepa- ration of nano-sized Mn3O4 crystals, a black colloidal solution containing nano-sized Mn3O4 crystals and the preferred lithium ...

  2. Screen printed nanosized ZnO thick film

    Indian Academy of Sciences (India)

    Unknown

    BINDU KRISHNAN* and V P N NAMPOORI†. Centre for Materials for Electronics Technology, Athani P O, Thrissur 680 771, India. †International School of Photonics, Cochin University of Science and Technology, Cochin 682 022, India. MS received 6 November 2004; revised 5 March 2005. Abstract. Nanosized ZnO was ...

  3. Crystallization of Organic Semiconductor Molecules in Nanosized Cavities

    DEFF Research Database (Denmark)

    Milita, Silvia; Dionigi, Chiara; Borgatti, Francesco

    2008-01-01

    The crystallization of an organic semiconductor, viz., tetrahexil-sexithiophene (H4T6) molecules, confined into nanosized cavities of a self-organized polystyrene beads template, has been investigated by means of in situ grazing incidence X-ray diffraction measurements, during the solvent...

  4. Synthesis of nanosized silver colloids by microwave dielectric heating

    Indian Academy of Sciences (India)

    Silver nanosized crystallites have been synthesized in aqueous and polyols viz., ethylene glycol and glycerol, using a microwave technique. Dispersions of colloidal silver have been prepared by the reduction of silver nitrate both in the presence and absence of stabilizer poly(vinylpyrolidone) (PVP). It was observed that ...

  5. Modification of unsaturated polyester resins using nano-size core ...

    African Journals Online (AJOL)

    Modification of unsaturated polyester resins using nano-size core-shell particles. MO Munyati, PA Lovell. Abstract. No Abstract Available Journal of Science and Technology Special Edition 2004: 24-31. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT.

  6. Magnetic properties of hexaferrite nanosized powders produced via mechanoactivation

    Directory of Open Access Journals (Sweden)

    Naiden E.P.

    2005-01-01

    Full Text Available A study of the relationship between structural parameters and principal magnetic characteristics of nanosized powders of hexagonal ferrimagnetics produced via mechanoactivation has been carried out. The models describing the influence of the size effects on temperatures of magnetic phase transformations, saturation magnetization and magnetic anisotropy of similar materials are discussed.

  7. Mössbauer and magnetization studies of nanosize chromium ferrite ...

    African Journals Online (AJOL)

    Nanosize chromium ferrite (CrF) powder samples were synthesized by citrate precursor route in the size range of 6 to 35 nm. The structural and magnetic behaviour of these samples were studied using X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and Mössbauer spectroscopic techniques. Synthesized ...

  8. Nanosize boride particles in heat-treated nickel base superalloys

    International Nuclear Information System (INIS)

    Zhang, H.R.; Ojo, O.A.; Chaturvedi, M.C.

    2008-01-01

    Grain boundary microconstituents in aged nickel-based superalloys were studied by transmission electron microscopy techniques. A nanosized M 5 B 3 boride phase, possibly formed by intergranular solute desegregation-induced precipitation, was positively identified. The presence of these intergranular nanoborides provides reasonable clarification of a previously reported reduction of grain boundary liquation temperature during the weld heat affected zone thermal cycle

  9. Membrane with Stable Nanosized Microstructure and Method for Producing same

    DEFF Research Database (Denmark)

    2010-01-01

    The present invention provides a membrane, comprising in this order a first catalyst layer, an electronically and ionically conducting layer having a nanosized microstructure, and a second catalyst layer, characterized in that the electronically and ionically conducting layer is formed from an el...... an electrolyte material, a grain growth inhibitor and/or grain boundary modifier, and a method for producing same....

  10. Electrodeposition of nano-sized bismuth on copper foil as electrocatalyst for reduction of CO2 to formate

    Science.gov (United States)

    Lv, Weixin; Zhou, Jing; Bei, Jingjing; Zhang, Rui; Wang, Lei; Xu, Qi; Wang, Wei

    2017-01-01

    Electrochemical reduction of carbon dioxide (CO2) to formate is energetically inefficient because high overpotential is required for reduction of CO2 to formate on most traditional catalysts. In this paper, a novel nano-sized Bi-based electrocatalyst deposited on a Cu foil has been synthesized, which can be used as a cathode for electrochemical reduction of CO2 to formate with a low overpotential (0.69 V) and a high selectivity (91.3%). The electrocatalyst can show excellent catalytic performance toward reduction of CO2 which can probably be attributed to the nano-sized structure and the surface oxide layer. The energy efficiency for reduction of CO2 to formate can reach to 50% when an IrxSnyRuzO2/Ti electrode is used as anode, it is one of the highest values found in the literatures and very practicable for sustainable fuel synthesis.

  11. High resolution photolithography using arrays of polystyrene and SiO2 micro- and nano-sized spherical lenses

    Science.gov (United States)

    Dvoretckaia, L. N.; Mozharov, A. M.; Mukhin, I. S.

    2017-11-01

    Photolithography mask made of close-packed array of micro- and nano-sized spherical lenses allows to obtain the ordered structures and provides highest “optical resolution/cost” ratio between all existing photolithography and laser direct writing methods. In this letter, we present results of modeling the propagation of a plane wave falling on the array of quartz (SiO2) microspherical lenses and focusing in the image reverse photoresist layer. We present here experimental results on fabrication of ordered arrays of submicron wells and columns and substrate preparation for growth of monocrystalline nanowires on metal surface using photolithography with mask of SiO2 microspheres. Such ordered nano-sized arrays of wells and columns can be used in fabrication of further growth of monocrystalline nanowires, quantum dots and production of plasmon structures.

  12. Heavy metal removal from water/wastewater by nanosized metal oxides: a review.

    Science.gov (United States)

    Hua, Ming; Zhang, Shujuan; Pan, Bingcai; Zhang, Weiming; Lv, Lu; Zhang, Quanxing

    2012-04-15

    Nanosized metal oxides (NMOs), including nanosized ferric oxides, manganese oxides, aluminum oxides, titanium oxides, magnesium oxides and cerium oxides, provide high surface area and specific affinity for heavy metal adsorption from aqueous systems. To date, it has become a hot topic to develop new technologies to synthesize NMOs, to evaluate their removal of heavy metals under varying experimental conditions, to reveal the underlying mechanism responsible for metal removal based on modern analytical techniques (XAS, ATR-FT-IR, NMR, etc.) or mathematical models, and to develop metal oxide-based materials of better applicability for practical use (such as granular oxides or composite materials). The present review mainly focuses on NMOs' preparation, their physicochemical properties, adsorption characteristics and mechanism, as well as their application in heavy metal removal. In addition, porous host supported NMOs are particularly concerned because of their great advantages for practical application as compared to the original NMOs. Also, some magnetic NMOs were included due to their unique separation performance. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. Synthesis, Characterization, and Magnetic Properties of Pure and EDTA-Capped NiO Nanosized Particles

    Directory of Open Access Journals (Sweden)

    H. T. Rahal

    2017-01-01

    Full Text Available The effect of ethylenediaminetetraacetic acid (EDTA as a capping agent on the structure, morphology, optical, and magnetic properties of nickel oxide (NiO nanosized particles, synthesized by coprecipitation method, was investigated. Nickel chloride hexahydrate and sodium hydroxide (NaOH were used as precursors. The resultant nanoparticles were characterized by X-ray diffraction (XRD, transmission electron microscopy (TEM, and scanning electron microscopy (SEM. XRD patterns showed that NiO have a face-centered cubic (FCC structure. The crystallite size, estimated by Scherrer formula, has been found in the range of 28–33 nm. It is noticed that EDTA-capped NiO nanoparticles have a smaller size than pure nanoparticles. Thus, the addition of 0.1 M capping agent EDTA can form a nucleation point for nanoparticles growth. The optical and magnetic properties were investigated by Fourier transform infrared spectroscopy (FTIR and UV-vis absorption spectroscopy (UV as well as electron paramagnetic resonance (EPR and magnetization measurements. FTIR spectra indicated the presence of absorption bands in the range of 402–425 cm−1, which is a common feature of NiO. EPR for NiO nanosized particles was measured at room temperature. An EPR line with g factor ≈1.9–2 is detected for NiO nanoparticles, corresponding to Ni2+ ions. The magnetic hysteresis of NiO nanoparticles showed that EDTA capping recovers the surface magnetization of the nanoparticles.

  14. Nanosized Hydroxyapatite Precipitation on the Ti—30Ta—xHf Alloys.

    Science.gov (United States)

    Lee, Kang; Jang, Jae- In; Han-Cheol, Choe

    2017-04-01

    In this study, we prepared hydroxyapatite (HAp) layer on the alkali treated Ti–30Ta–xHf alloys using electrochemical deposition method. Ti–30Ta–xHf alloys was anodized in 5 M NaOH solution at 0.3 A for 10 min. Alkali treated Ti–30Ta–xHf surface formed by anodization step which acted as templates and anchorage for growth of the HAp during subsequent pulsed electrochemical deposition process at 85 °C. The phase and morphologies of deposited HAp layer were affected by the Hf contents of Ti–30Ta–xHf alloys. The nano-scale rod-like HAp layer was formed on untreated Ti–30Ta–xHf alloys with partially low crystallinity. In the case of alkali treated Ti–30Ta–xHf, nano-sized needle-like layers were transferred to nano-flake surface and denser morphology as Hf content increased.

  15. Mixing of nanosize particles by magnetically assisted impaction techniques

    Science.gov (United States)

    Scicolone, James V.

    Nanoparticles and nanocomposites offer unique properties that arise from their small size, large surface area, and the interactions of phases at their interfaces, and are attractive for their potential to improve performance of drugs, biomaterials, catalysts and other high-value-added materials. However, a major problem in utilizing nanoparticles is that they often lose their high surface area due to grain growth. Creating nanostructured composites where two or more nanosized constituents are intimately mixed can prevent this loss in surface area, but in order to obtain homogeneous mixing, de-agglomeration of the individual nanoparticle constituents is necessary. Due to high surface area, nano-particles form very large, fractal agglomerates. The structure of these agglomerates can have a large agglomerate composed of sub-agglomerates (SA), which itself consists of primary agglomerates (PA), that contain chain or net like nano-particle structures; typically sub-micron size. Thus the final agglomerate has a hierarchical, fractal structure, and depending upon the forces applied, it could break down to a certain size scale. The agglomerates can be fairly porous and fragile or they could be quite dense, based on primary particle size and its surface energy. Thus depending upon the agglomerate strength at different length scales, one could achieve deagglomeration and subsequent mixing at varying length scale. A better understanding of this can have a major impact on the field of nano-structured materials; thus the long term objective of this project is to gain fundamental understanding of deagglomeration and mixing of nano-agglomerates. Dry mixing is in general not effective in achieving desired mixing at nanoscale, whereas wet mixing suffers from different disadvantages like nanomaterial of interest should be insoluble, has to wet the liquid, and involves additional steps of filtration and drying. This research examines the use of environmentally friendly a novel

  16. Electrodeposition of nano-sized bismuth on copper foil as electrocatalyst for reduction of CO{sub 2} to formate

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Weixin; Zhou, Jing; Bei, Jingjing [School of Chemistry and Chemical Engineering, Yancheng Institute of Technology, Yancheng, 224051 (China); Zhang, Rui, E-mail: zhangrui@ycit.cn [School of Chemistry and Chemical Engineering, Yancheng Institute of Technology, Yancheng, 224051 (China); Wang, Lei [Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education of the People’s Republic of China, Heilongjiang University, Harbin, 150080 (China); Xu, Qi [School of Chemistry and Chemical Engineering, Yancheng Institute of Technology, Yancheng, 224051 (China); Wang, Wei, E-mail: wangw@ycit.edu.cn [School of Chemistry and Chemical Engineering, Yancheng Institute of Technology, Yancheng, 224051 (China)

    2017-01-30

    Highlights: • Bi/Cu electrode was prepared by depositing nano-sized Bi catalyst on Cu foil. • The Bi/Cu electrode can reduce CO{sub 2} to formate with a low overpotential. • The energy efficiency for reduction of CO{sub 2} to formate can reach to 50%. • A Tafel slope of 128 mV decade{sup −1} was observed for producing formate. - Abstract: Electrochemical reduction of carbon dioxide (CO{sub 2}) to formate is energetically inefficient because high overpotential is required for reduction of CO{sub 2} to formate on most traditional catalysts. In this paper, a novel nano-sized Bi-based electrocatalyst deposited on a Cu foil has been synthesized, which can be used as a cathode for electrochemical reduction of CO{sub 2} to formate with a low overpotential (0.69 V) and a high selectivity (91.3%). The electrocatalyst can show excellent catalytic performance toward reduction of CO{sub 2} which can probably be attributed to the nano-sized structure and the surface oxide layer. The energy efficiency for reduction of CO{sub 2} to formate can reach to 50% when an Ir{sub x}Sn{sub y}Ru{sub z}O{sub 2}/Ti electrode is used as anode, it is one of the highest values found in the literatures and very practicable for sustainable fuel synthesis.

  17. Wear Resistance of Austempered Ductile Iron with Nanosized Additives

    Science.gov (United States)

    Kaleicheva, J. K.; Mishev, V.

    2018-01-01

    The wear resistance, microstructure and mechanical properties of austempered ductile iron (ADI) with nanosized additives of cubic boron nitride cBN are investigated. Samples of ductile iron are put under austhempering at the following conditions: heating at 900°С, 1 h and isothermal retention at 280оС, 2 h and 380°С, 2 h with the aim to achieve a lower bainitic structure and an upper bainitic structure. The experimental wear testing of austempered ductile irons is performed in friction conditions of a fixed abrasive by a cinematic scheme „pin - disc” using an accelerated testing method and device. The microstructure of the ADI is investigated by metallographic and X-Ray analyses. The Vickers hardness testing and impact strength examination are carried out. The influence of the nanosized additives of cBN on the wear resistance, microstructure, impact strength and hardness of the ADI is investigated.

  18. Cellular detonations in nano-sized aluminum particle gas suspensions

    Science.gov (United States)

    Khmel, TA

    2017-10-01

    Formation of cellular detonation structures in monodisperse nano-sized aluminum particle – oxygen suspensions is studied by methods of numerical simulations of two-dimensional detonation flows. The detonation combustion are described within the semi-empirical model developed earlier which takes into account transition of the regime of aluminum particle combustion from diffusion to kinetic for micro-sized and nano-sized particles. The free-molecular effects are considered in the processes of heat and velocity relaxation of the phases. The specific features of the cellular detonation of nanoparticle suspensions comparing with micron-sized suspensions are irregular cellular structures, much higher pick pressure values, and relatively larger detonation cells. This is due to high value of activation energy of reduced chemical reaction of aluminum particle combustion in kinetic regime.

  19. Structural and magnetic properties of mechanochemically synthesized nanosized yttrium titanate

    Directory of Open Access Journals (Sweden)

    Barudžija Tanja

    2012-01-01

    Full Text Available Nanosized perovskite YTiO3 with the mean crystallite size of 18 nm was synthesized for the first time by mechanochemical treatment. The mechanochemical solid state reaction between commercial Y2O3 powder and mechanochemically synthesized TiO powder in molar ratio 0.5:1 was completed for 3 h in a high-energy planetary ball mill in argon atmosphere. The heating in vacuum at 1150 °C for 12 h transforms nanosized YTiO3 to a well-crystallized single-phase perovskite YTiO3. Both samples were characterized by X-ray diffraction (XRD and thermogravimetric (TGA/DTA analyses, as well as superconducting quantum interference device magnetometer (SQUID measurements.

  20. Degradation of simazine from aqueous solutions by diatomite-supported nanosized zero-valent iron composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Zhiming [School of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing 100083 (China); Chemistry Discipline, Faculty of Science and Technology, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane, Queensland 4001 (Australia); Zheng, Shuilin [School of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing 100083 (China); Ayoko, Godwin A.; Frost, Ray L. [Chemistry Discipline, Faculty of Science and Technology, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane, Queensland 4001 (Australia); Xi, Yunfei, E-mail: y.xi@qut.edu.au [Chemistry Discipline, Faculty of Science and Technology, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane, Queensland 4001 (Australia)

    2013-12-15

    Graphical abstract: Nanosized zero-valent iron (nZVI) particles were deposited onto acid-leached diatomite through centrifugation or rotary evaporation. The synthesis schematic diagram and morphology of the prepared nZVI/diatomite composites are shown in the illustration. The removal efficiency for herbicide simazine by nZVI/diatomite composites was compared with that of the pristine nZVI and the commercial iron powder. -- Highlights: • Diatomite-supported nanosized zero-valent iron composite was synthesised. • The obtained composites were characterised by XRD, SEM–EDS, TEM and XPS. • The removal efficiency for simazine in water were studied. • The prepared composite showed potential prospects in environmental remediation. -- Abstract: A novel composite material based on deposition of nanosized zero-valent iron (nZVI) particles on acid-leached diatomite was synthesised for the removal of a chlorinated contaminant in water. The nZVI/diatomite composites were characterised by X-ray diffraction, scanning electron microscopy, elemental analysis, transmission electron microscopy and X-ray photoelectron spectroscopy. Compared with the pure nZVI particles, better dispersion of nZVI particles on the surface or inside the pores of diatom shells was observed. The herbicide simazine was selected as the model chlorinated contaminant and the removal efficiency by nZVI/diatomite composite was compared with that of the pristine nZVI and commercial iron powder. It was found that the diatomite supported nZVI composite material prepared by centrifugation exhibits relatively better efficient activity in decomposition of simazine than commercial Fe, lab synthesised nZVI and composite material prepared via rotary evaporation, and the optimum experimental conditions were obtained based on a series of batch experiments. This study on immobilising nZVI particles onto diatomite opens a new avenue for the practical application of nZVI and the diatomite-supported nanosized zero

  1. Raman scattering in nanosized nickel oxide NiO

    International Nuclear Information System (INIS)

    Mironova-Ulmane, N; Kuzmin, A; Steins, I; Grabis, J; Sildos, I; Paers, M

    2007-01-01

    Magnetic ordering in nanosized (100 and 1500 nm) nickel oxide NiO powders, prepared by the plasma synthesis method, was studied using Raman scattering spectroscopy in a wide range of temperatures from 10 to 300 K. It was observed that the intensity of two-magnon band decreases rapidly for smaller crystallites size. This effect is attributed to a decrease of antiferromagnetic spin correlations and leads to the antiferromagnetic-to-paramagnetic phase transition

  2. Electrical and Optical Properties of Nanosized Perovskite-type La ...

    African Journals Online (AJOL)

    Electrical and Optical Properties of Nanosized Perovskite-type La 0.5 Ca 0.5 MO 3 (M=Co,Ni) prepared using a Sol-Gel Method. ... calculate the absorption coefficient (α) as a function of photon energy (hυ) and the obtained results indicate that the optical band gap energy (Eg) for LCNO sample is smaller than that of LCCO.

  3. Superconducting film magnetic flux transformer with micro- and nanosized branches

    Directory of Open Access Journals (Sweden)

    Levan Ichkitidze

    2013-06-01

    Full Text Available The object of the study is a superconducting film magnetic flux transformer comprising two square shaped loops with the tapering active strips and a magnetosensitive film element between them. It is shown that splitting of the active strips into parallel micro- and nanosized superconducting branches and slits increases the gain factor of the transformer, i. e., the concentration of an external magnetic field on the magnetosensitive element, by a factor of more than four.

  4. Wear Behavior of Austempered Ductile Iron with Nanosized Additives

    Directory of Open Access Journals (Sweden)

    J. Kaleicheva

    2014-03-01

    Full Text Available The microstructure and properties of austempered ductile iron (ADI strengthened with nanosized addtives of titanium nitride + titanium carbonitride (TiN + TiCN, titanium nitride TiN and cubic boron nitride cBN are investigated. The TiN, TiCN and cBN, nanosized particles are coated by electroless nickel coating EFTTOM-NICKEL prior to the edition to the melt. The spheroidal graphite iron samples are undergoing an austempering, including heating at 900 оС for an hour, after that isothermal retention at 280 оС, 2 h and 380 оС, 2h. The metallographic analysis by optical metallographic microscope GX41 OLIMPUS and hardness measurements by Vickers Method are performed. The structure of the austempered ductile iron consists of lower bainite and upper bainite.Experimental investigation of the wear by fixed abrasive are also carried out. The influence of the nanosized additives on the microstructure, mechanical and tribological properties of the austempered ductile irons (ADI is studied.

  5. In vitro study of nano-sized zinc doped bioactive glass

    Energy Technology Data Exchange (ETDEWEB)

    Goh, Yi-Fan; Alshemary, Ammar Z.; Akram, Muhammad [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM skudai, Johor Darul Ta' zim (Malaysia); Abdul Kadir, Mohammed Rafiq [Medical Implant Technology Group, Faculty of Biomedical Engineering and Health Science, Universiti Teknologi Malaysia, 81310 UTMJohor Bahru (Malaysia); Hussain, Rafaqat, E-mail: rafaqat@kimia.fs.utm.my [IbnuSina Institute for Fundamental Science Studies, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor DarulTa' zim (Malaysia)

    2013-01-15

    Surface reactivity in physiological fluid has been linked to bioactivity of a material. Past research has shown that bioactive glass containing zinc has the potential in bone regeneration field due to its enhanced bioactivity. However, results from literature are always contradictory. Therefore, in this study, surface reactivity of bioactive glass containing zinc was evaluated through the study of morphology and composition of apatite layer formed after immersion in simulated body fluid (SBF). Nano-sized bioactive glass with 5 and 10 mol% zinc were synthesized through quick alkali sol-gel method. The synthesized Zn-bioglass was characterized using field emission scanning electron microscope (FESEM), energy dispersive X-ray spectrometer (EDX), X-ray diffractometer (XRD) and Fourier transform infrared spectrometer (FTIR). Samples after SBF immersion were characterized using scanning electron microscope (SEM) and EDX. Morphological study through SEM showed the formation of spherical apatite particles with Ca/P ratio closer to 1.67 on the surface of 5 mol% Zn-bioglass. Whereas, the 10 mol% Zn-bioglass samples induced the formation of flake-like structure of calcite in addition to the spherical apatite particles with much higher Ca/P ratio. Our results suggest that the higher Zn content increases the bioactivity through the formation of bone-bonding calcite as well as the spherical apatite particles. -- Highlights: Black-Right-Pointing-Pointer Nano-sized bioactive glasses were synthesized through quick alkali sol-gel method. Black-Right-Pointing-Pointer 5 and 10 mol% Zn-bioglass induced the formation of spherical particles in SBF test. Black-Right-Pointing-Pointer 10 mol% Zn-bioglass also induced the formation of flake-like structure. Black-Right-Pointing-Pointer The flake-like structure is calcium carbonate; spherical particles are apatite. Black-Right-Pointing-Pointer High Zn contents negatively influence the chemical composition of the apatite layer.

  6. Tailoring properties of porous Poly (vinylidene fluoride) scaffold through nano-sized 58s bioactive glass.

    Science.gov (United States)

    Shuai, Cijun; Huang, Wei; Feng, Pei; Gao, Chengde; Shuai, Xiong; Xiao, Tao; Deng, Youwen; Peng, Shuping; Wu, Ping

    2016-01-01

    The biological properties of porous poly (vinylidene fluoride) (PVDF) scaffolds fabricated by selective laser sintering were tailored through nano-sized 58s bioactive glass. The results showed that 58s bioactive glass distributed evenly in the PVDF matrix. There were some exposed particles on the surface which provided attachment sites for biological response. It was confirmed that the scaffolds had highly bioactivity by the formation of bone-like apatite in simulated body fluid. And the bone-like apatite became dense with the increase in 58s bioactive glass and culture time. Moreover, the scaffolds were suitable for cell adhesion and proliferation compared with the PVDF scaffolds without 58s bioactive glass. The research showed that the PVDF/58s bioactive glass scaffolds had latent application in bone tissue engineering.

  7. FORMATION MECHANISM OF NANOSIZED TIN OXIDE (SnO2 POWDER DURING HYDROTHERMAL SYNTHESIS

    Directory of Open Access Journals (Sweden)

    M. Ozan ÖZER

    2011-06-01

    Full Text Available Preparation of nanosized SnO₂ electroceramic powders via hydrothermal synthesis was investigated as a function of initial concentration and treatment time in order to understand the formation and growth mechanisms. SnO₂ powder was successfully synthesized from the hydrous tin oxide by hydro- thermal synthesis at 200°C. Crystalline SnO₂ particles with a specific surface area as high as 170 m₂/g were produced in a single step without requiring any calcination process. As initial concentration of metal cation increases from 0.0125 to 0.05 M, an Ostwald ripening type growth process was observed in the crystallite size from 3.1 to 4.6 nm. Evolution of tin oxide particles was also investigated by al- tering the treatment time from 1 to 24 h and a diffusion controlled growth behavior was observed as a function of synthesis time.

  8. Ecotoxicity of nanosized TiO2. Review of in vivo data

    International Nuclear Information System (INIS)

    Menard, Anja; Drobne, Damjana; Jemec, Anita

    2011-01-01

    This report presents an exhaustive literature review of data on the effect of nanoparticulate TiO 2 on algae, higher plants, aquatic and terrestrial invertebrates and freshwater fish. The aim, to identify the biologically important characteristics of the nanoparticles that have most biological significance, was unsuccessful, no discernable correlation between primary particle size and toxic effect being apparent. Secondary particle size and particle surface area may be relevant to biological potential of nanoparticles, but insufficient confirmatory data exist. The nanotoxicity data from thirteen studies fail to reveal the characteristics actually responsible for their biological reactivity because reported nanotoxicity studies rarely carry information on the physicochemical characteristics of the nanoparticles tested. A number of practical measures are suggested which should support the generation of reliable QSAR models and so overcome this data inadequacy. - Ecotoxicity of nanosized TiO 2 .

  9. Ecotoxicity of nanosized TiO{sub 2}. Review of in vivo data

    Energy Technology Data Exchange (ETDEWEB)

    Menard, Anja, E-mail: anja.menard@gmail.com [University of Ljubljana, Faculty of Pharmacy, Askerceva cesta 7, SI-1000 Ljubljana (Slovenia); Drobne, Damjana, E-mail: Damjana.Drobne@bf.uni-lj.si [University of Ljubljana, Biotechnical Faculty, Department of Biology, Vecna pot 111, SI-1000 Ljubljana (Slovenia); Centre of Excellence in Advanced Materials and Technologies for the Future (CO NAMASTE), Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Centre of Excellence in Nanoscience and Nanotechnology (CO Nanocenter), Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Jemec, Anita, E-mail: anita.jemec@ki.si [National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana (Slovenia)

    2011-03-15

    This report presents an exhaustive literature review of data on the effect of nanoparticulate TiO{sub 2} on algae, higher plants, aquatic and terrestrial invertebrates and freshwater fish. The aim, to identify the biologically important characteristics of the nanoparticles that have most biological significance, was unsuccessful, no discernable correlation between primary particle size and toxic effect being apparent. Secondary particle size and particle surface area may be relevant to biological potential of nanoparticles, but insufficient confirmatory data exist. The nanotoxicity data from thirteen studies fail to reveal the characteristics actually responsible for their biological reactivity because reported nanotoxicity studies rarely carry information on the physicochemical characteristics of the nanoparticles tested. A number of practical measures are suggested which should support the generation of reliable QSAR models and so overcome this data inadequacy. - Ecotoxicity of nanosized TiO{sub 2}.

  10. Photocatalytic Degradation of Malachite Green Using Nano-sized cerium-iron Oxide

    Directory of Open Access Journals (Sweden)

    K. L. Ameta

    2014-05-01

    Full Text Available Nano-sized cerium-iron oxide nanoparticles has been synthesized, characterized and explored as an efficient photocatalyst for the photocatalytic degradation of malachite green. The effects of different variables on degradation of dye were optimized such as the pH of the dye solution, dye concentration, amount of photocatalyst and light intensity. About 91% degradation of dye of 2×10-5 M concentration was observed after 2 hours at 8.5 pH and 600 Wm-2 light intensity. The reason for the high catalytic activity of the synthesized nanoparticles is ascribed to the high surface area which determines the active sites of the catalyst and accelerates the photocatalytic degradation.

  11. Spin-resolved magnetic studies of focused ion beam etched nano-sized magnetic structures

    International Nuclear Information System (INIS)

    Li Jian; Rau, Carl

    2005-01-01

    Scanning ion microscopy with polarization analysis (SIMPA) is used to study the spin-resolved surface magnetic structure of nano-sized magnetic systems. SIMPA is utilized for in situ topographic and spin-resolved magnetic domain imaging as well as for focused ion beam (FIB) etching of desired structures in magnetic or non-magnetic systems. Ultra-thin Co films are deposited on surfaces of Si(1 0 0) substrates, and ultra-thin, tri-layered, bct Fe(1 0 0)/Mn/bct Fe(1 0 0) wedged magnetic structures are deposited on fcc Pd(1 0 0) substrates. SIMPA experiments clearly show that ion-induced electrons emitted from magnetic surfaces exhibit non-zero electron spin polarization (ESP), whereas electrons emitted from non-magnetic surfaces such as Si and Pd exhibit zero ESP, which can be used to calibrate sputtering rates in situ. We report on new, spin-resolved magnetic microstructures, such as magnetic 'C' states and magnetic vortices, found at surfaces of FIB patterned magnetic elements. It is found that FIB milling has a negligible effect on surface magnetic domain and domain wall structures. It is demonstrated that SIMPA can evolve into an important and efficient tool to study magnetic domain, domain wall and other structures as well as to perform magnetic depth profiling of magnetic nano-systems to be used in ultra-high density magnetic recording and in magnetic sensors

  12. Surface Effects in Magnetic Nanoparticles

    CERN Document Server

    Fiorani, Dino

    2005-01-01

    This volume is a collection of articles on different approaches to the investigation of surface effects on nanosized magnetic materials, with special emphasis on magnetic nanoparticles. The book aims to provide an overview of progress in the understanding of surface properties and surface driven effects in magnetic nanoparticles through recent results of different modeling, simulation, and experimental investigations.

  13. Stabilization of Nanosized TiO2 Particles on Knitted Cotton/Polyester Fabric by Citric Acid for Self-cleaning and Discoloration of Reactive Black 5 from Waste Water

    Directory of Open Access Journals (Sweden)

    Majid montazer

    2012-11-01

    Full Text Available Cotton/polyester knitted fabrics as a major production of textile industry was treated with titanium dioxide nanosized particles. The treated fabric with nanosized TiO2 became whiter with a good self-cleaning property. Also the discoloration of Reactive Black 5 dye was studied and reported. The stabilization of TiO2 on cotton/polyester knitted fabrics by citric acid (CA with sodium hypophosphate (SHP as a catalyst was also investigated. These samples showed a good self-cleaning property through discoloration of C.I. Direct Red 80. In addition, using CA in the presence of SHP, helped to stabilize the TiO2 nanosized particles on the fabric surface even after 10 washing cycles. The images of scanning electron microscopy and X-Ray mapping, EDX analyses confirmed the presence of TiO2 nanoparticles on the fabric surfaces even after 10 washing cycles.

  14. Study on the Size-Dependent Oxidation Reaction Kinetics of Nanosized Zinc Sulfide

    Directory of Open Access Journals (Sweden)

    Qing-Shan Fu

    2014-01-01

    Full Text Available Numerous oxidation problems of nanoparticles are often involved during the preparation and application of nanomaterials. The oxidation rate of nanomaterials is much faster than bulk materials due to nanoeffect. Nanosized zinc sulfide (nano-ZnS and oxygen were chosen as a reaction system. The influence regularities were discussed and the influence essence was elucidated theoretically. The results indicate that the particle size can remarkably influence the oxidation reaction kinetics. The rate constant and the reaction order increase, while the apparent activation energy and the preexponential factor decrease with the decreasing particle size. Furthermore, the logarithm of rate constant, the apparent activation energy and the logarithm of preexponential factor are linearly related to the reciprocal of particle diameter, respectively. The essence is that the rate constant is influenced by the combined effect of molar surface energy and molar surface entropy, the reaction order by the molar surface area, the apparent activation energy, by the molar surface energy, and the preexponential factor by the molar surface entropy. The influence regularities and essence can provide theoretical guidance to solve the oxidation problems involved in the process of preparation and application of nanomaterials.

  15. Preparation, characterization and application of nanosized copper ferrite photocatalysts for dye degradation under UV irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Zaharieva, Katerina, E-mail: zaharieva@ic.bas.bg [Institute of Catalysis, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Block 11, 1113 Sofia (Bulgaria); Rives, Vicente, E-mail: vrives@usal.es [GIR-QUESCAT, Dpto. Química Inorgánica, Universidad de Salamanca, 37008 Salamanca (Spain); Tsvetkov, Martin, E-mail: mptsvetkov@gmail.com [Faculty of Chemistry and Pharmacy, St. Kliment Ohridski University of Sofia, 1 J. Bourchier Blvd., 1164 Sofia (Bulgaria); Cherkezova-Zheleva, Zara, E-mail: zzhel@ic.bas.bg [Institute of Catalysis, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Block 11, 1113 Sofia (Bulgaria); Kunev, Boris, E-mail: bkunev@ic.bas.bg [Institute of Catalysis, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Block 11, 1113 Sofia (Bulgaria); Trujillano, Raquel, E-mail: rakel@usal.es [GIR-QUESCAT, Dpto. Química Inorgánica, Universidad de Salamanca, 37008 Salamanca (Spain); Mitov, Ivan, E-mail: mitov@ic.bas.bg [Institute of Catalysis, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Block 11, 1113 Sofia (Bulgaria); Milanova, Maria, E-mail: nhmm@wmail.chem.uni-sofia.bg [Faculty of Chemistry and Pharmacy, St. Kliment Ohridski University of Sofia, 1 J. Bourchier Blvd., 1164 Sofia (Bulgaria)

    2015-06-15

    Nanosized copper ferrite-type materials (Cu{sub x}Fe{sub 3–x}O{sub 4}, 0 ≤ x ≤ 1) have been prepared by combination of co-precipitation and mechanochemical activation and/or thermal treatment. The crystalline structure and morphology of the obtained ferrite nanopowders have been characterized by different instrumental methods, such as Powder X-ray diffraction (PXRD), Mössbauer and FT-IR spectroscopies, specific surface area and porosity measurements, thermal analyses (Differential Thermal Analysis and Thermogravimetric Analysis) and Temperature-Programmed Reduction. The average crystallite size of copper ferrites ranged between 7.8 and 14.7 nm and show a superparamagnetic and collective magnetic excitations nature. The photocatalytic decolorization of Malachite green oxalate under different UV illumination intervals was examined using these copper ferrites as photocatalysts. The results indicate that the prepared nanostructured copper ferrites showed enhanced photocatalytic activity and amount adsorbed Malachite Green dye. The co-precipitated nanosized copper ferrite powder with a low content of copper metal ions in a magnetite host structure (Cu{sub 0.25}Fe{sub 2.75}O{sub 4}) showed an apparent pseudo-first-order rate constant 15.4 × 10{sup −3} min{sup −1} and an amount adsorbed Malachite Green as model organic dye pollutant per 1 g catalyst of 33.4 ppm/g after the dark period. The results confirm that the copper ferrites can be suitable for photocatalytic treatment of wastewaters containing organic dyes. The new aspect of presented investigations is to study the influence of different degree of incorporation of copper ions into the magnetite host structure and preparation methods on the photocatalytic properties of nanosized copper ferrite materials and obtaining of potential photocatalyst (Cu{sub 0.25}Fe{sub 2.75}O{sub 4}) with higher photocatalytic activity (15.4 × 10{sup −3} min{sup −1}) than that of the standard referent Degussa P25 (12 × 10

  16. Preparation, characterization and application of nanosized copper ferrite photocatalysts for dye degradation under UV irradiation

    International Nuclear Information System (INIS)

    Zaharieva, Katerina; Rives, Vicente; Tsvetkov, Martin; Cherkezova-Zheleva, Zara; Kunev, Boris; Trujillano, Raquel; Mitov, Ivan; Milanova, Maria

    2015-01-01

    Nanosized copper ferrite-type materials (Cu x Fe 3–x O 4 , 0 ≤ x ≤ 1) have been prepared by combination of co-precipitation and mechanochemical activation and/or thermal treatment. The crystalline structure and morphology of the obtained ferrite nanopowders have been characterized by different instrumental methods, such as Powder X-ray diffraction (PXRD), Mössbauer and FT-IR spectroscopies, specific surface area and porosity measurements, thermal analyses (Differential Thermal Analysis and Thermogravimetric Analysis) and Temperature-Programmed Reduction. The average crystallite size of copper ferrites ranged between 7.8 and 14.7 nm and show a superparamagnetic and collective magnetic excitations nature. The photocatalytic decolorization of Malachite green oxalate under different UV illumination intervals was examined using these copper ferrites as photocatalysts. The results indicate that the prepared nanostructured copper ferrites showed enhanced photocatalytic activity and amount adsorbed Malachite Green dye. The co-precipitated nanosized copper ferrite powder with a low content of copper metal ions in a magnetite host structure (Cu 0.25 Fe 2.75 O 4 ) showed an apparent pseudo-first-order rate constant 15.4 × 10 −3 min −1 and an amount adsorbed Malachite Green as model organic dye pollutant per 1 g catalyst of 33.4 ppm/g after the dark period. The results confirm that the copper ferrites can be suitable for photocatalytic treatment of wastewaters containing organic dyes. The new aspect of presented investigations is to study the influence of different degree of incorporation of copper ions into the magnetite host structure and preparation methods on the photocatalytic properties of nanosized copper ferrite materials and obtaining of potential photocatalyst (Cu 0.25 Fe 2.75 O 4 ) with higher photocatalytic activity (15.4 × 10 −3 min −1 ) than that of the standard referent Degussa P25 (12 × 10 −3 min −1 ) for degradation of organic dye

  17. Waste utilization for the controlled synthesis of nanosized hydroxyapatite

    Energy Technology Data Exchange (ETDEWEB)

    Nayar, Suprabha, E-mail: Suprabha.nayar@gmail.com [National Metallurgical Laboratory, Jamshedpur (India); Guha, Avijit [National Metallurgical Laboratory, Jamshedpur (India)

    2009-05-05

    This work uses biomolecules in waste and medicinally important materials for the synthesis of hydroxyapatite nanoparticles. Orange and potato peel, eggshell, papaya leaf and calendula flower extracts have varied biomolecules, which exert a significant, control on the in situ synthesis of nanosized hydroxyapatite particles. The biomimetic synthesis of inorganic particles using known matrices is already well established, however, there are only a few reports using compound extracts. The synthesized nanocomposite has been characterized using X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy studies. Role of varied biomolecules in controlled inorganic synthesis may have tremendous technological impact.

  18. Reflection characterization of nano-sized dielectric structure in Morpho butterfly wings

    Science.gov (United States)

    Zhu, Dong

    2017-10-01

    Morpho butterflies living in Central and South America are well-known for their structural-colored blue wings. The blue coloring originates from the interaction of light with nano-sized dielectric structures that are equipped on the external surface of scales covering over their wings. The high-accuracy nonstandard finite-difference time domain (NS-FDTD) method is used to investigate the reflection characterization from the nanostructures. In the NS-FDTD calculation, a computational model is built to mimic the actual tree-like multilayered structures wherever possible using the hyperbolic tangent functions. It is generally known that both multilayer interference and diffraction grating phenomena can occur when light enters the nano-sized multilayered structure. To answer the question that which phenomenon is mainly responsible for the blue coloring, the NS-FDTD calculation is performed under various incidence angles at wavelengths from 360 to 500 nm. The calculated results at one incident wavelength under different incidence angles are visualized in a two-dimensional mapping image, where horizontal and vertical axes are incidence and reflection angles, respectively. The images demonstrate a remarkable transition from a ring-like pattern at shorter wavelengths to a retro-reflection pattern at longer wavelengths. To clarify the origin of the pattern transition, the model is separated into several simpler parts and compared their mapping images with the theoretical diffraction calculations. It can be concluded that the blue coloring at longer wavelengths is mainly caused by the cooperation of multilayer interference and retro-reflection while the effect of diffraction grating is predominant at shorter wavelengths.

  19. Luminescence properties of YAG: Nd 3 nano-sized ceramic powders ...

    Indian Academy of Sciences (India)

    Nano-sized ceramic powders with weaker aggregation of Nd3+-doped yttrium aluminum garnet (YAG:Nd3+) were synthesized via co-microemulsion and microwave heating. This method provides a limited small space in a micelle for the formation of nano-sized precursors. It also requires a very short heating time, thus ...

  20. Application of Nanosize Zeolite Molecular Sieves for Medical Oxygen Concentration

    Directory of Open Access Journals (Sweden)

    Mingfei Pan

    2017-07-01

    Full Text Available The development of a portable oxygen concentrator is of prime significance for patients with respiratory problems. This paper presents a portable concentrator prototype design using the pressure/vacuum swing adsorption (PVSA cycle with a deep evacuation step (−0.82 barg instead of desorption with purge flow to simplify the oxygen production process. The output of the oxygen concentrator is a ~90 vol % enriched oxygen stream in a continuous adsorption and desorption cycle (cycle time ~90 s. The size of the adsorption column is 3 cm in diameter and 20 cm in length. A Li+ exchanged 13X nanosize zeolite is used as the adsorbent to selectively adsorb nitrogen from air. A dynamic model of the pressure and vacuum swing adsorption units was developed to study the pressurization and depressurization process inside the microporous area of nanosized zeolites. The describing equations were solved using COMSOL Multiphysics Chemical Engineering module. The output flow rate and oxygen concentration results from the simulation model were compared with the experimental data. Velocity and concentration profiles were obtained to study the adsorption process and optimize the operational parameters.

  1. Antibacterial properties of artificial eyes containing nano-sized particle silver.

    Science.gov (United States)

    Yang, Jae Wook; Choi, Jae-won; Lee, Sul Gee; Kim, Dong Soo

    2011-03-01

    The long-term use of an artificial eyes can lead to complications. Persistent physical stimulation and foreign body contact cause secondary infections. Secondary infection is an important complication after the placement of a artificial eyes and may be difficult to control without removing the artificial eyes. Because of these complications, patients get difficulties to wear prosthesis. Furthermore artificial eyes can change the normal bacterial flora of the patient's conjunctiva. Such postoperative infections might be overcome by improving the antimicrobial properties of the prosthesis surface. The space in the mold previously occupied by wax was filled with polymethyl methacrylate (PMMA) resin containing silver at a concentration of 300-700 ppm (parts per million) and the prosthesis was then heat cured. Microorganisms were grown on the treated and control surfaces. We cultured for 24 hours, then counted the number of bacteria in resin compositions containing nano-sized silver particles and controls (Stomacher 400(®) POLY-BAG). The surface of the artificial eye containing silver grew significantly fewer Streptococcus pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli on in vitro bacterial cultures. The antimicrobial activity was 4.8-6.2 times stronger than for the controls. The numbers of bacteria decreased by 99.9% using the PMMA resin containing silver. The artificial eyes containing silver that were produced in this study have antibacterial activity, cause little eye discharge, and emit far-infrared rays and anions, all of which promote the ocular health of the person wearing the artificial eye.

  2. Chances and limitations of nanosized titanium dioxide practical application in view of its physicochemical properties

    Science.gov (United States)

    Bogdan, Janusz; Jackowska-Tracz, Agnieszka; Zarzyńska, Joanna; Pławińska-Czarnak, Joanna

    2015-02-01

    Nanotechnology is a field of science that is nowadays developing in a dynamic way. It seems to offer almost endless opportunities of contribution to many areas of economy and human activity, in general. Thanks to nanotechnology, the so-called nanomaterials can be designed. They present structurally altered materials, with their physical, chemical and biological properties entirely differing from properties of the same materials manufactured in microtechnology. Nanotechnology creates a unique opportunity to modify the matter at the level of atoms and particles. Therefore, it has become possible to obtain items displaying new, useful properties, i.e. self-disinfecting and self-cleaning surfaces. Those surfaces are usually covered by a thin layer of a photocatalyst. The role of the photocatalyst is most of the time performed by the nanosized titanium dioxide (nano-TiO2). Excitation of nano-TiO2 by ultraviolet radiation initiates advanced oxidation processes and reactions leading to the creation of oxygen vacancies that bind water particles. As a result, photocatalytic surfaces are given new properties. Those properties can then be applied in a variety of disciplines, such as medicine, food hygiene, environmental protection or building industry. Practically, the applications include inactivation of microorganisms, degradation of toxins, removing pollutants from buildings and manufacturing of fog-free windows or mirrors.

  3. Three-dimensional analysis of the swimming behavior of Daphnia magna exposed to nanosized titanium dioxide.

    Directory of Open Access Journals (Sweden)

    Christian Noss

    Full Text Available Due to their surface characteristics, nanosized titanium dioxide particles (nTiO2 tend to adhere to biological surfaces and we thus hypothesize that they may alter the swimming performance and behavior of motile aquatic organisms. However, no suitable approaches to address these impairments in swimming behavior as a result of nanoparticle exposure are available. Water fleas Daphnia magna exposed to 5 and 20 mg/L nTiO2 (61 nm; polydispersity index: 0.157 in 17.46 mg/L stock suspension for 96 h showed a significantly (p<0.05 reduced growth rate compared to a 1-mg/L treatment and the control. Using three-dimensional video observations of swimming trajectories, we observed a treatment-dependent swarming of D. magna in the center of the test vessels during the initial phase of the exposure period. Ensemble mean swimming velocities increased with increasing body length of D. magna, but were significantly reduced in comparison to the control in all treatments after 96 h of exposure. Spectral analysis of swimming velocities revealed that high-frequency variance, which we consider as a measure of swimming activity, was significantly reduced in the 5- and 20-mg/L treatments. The results highlight the potential of detailed swimming analysis of D. magna for the evaluation of sub-lethal mechanical stress mechanisms resulting from biological surface coating and thus for evaluating the effects of nanoparticles in the aquatic environment.

  4. Nanosized f.c.c. thallium inclusions in aluminium

    International Nuclear Information System (INIS)

    Johnson, E.; Johansen, A.; Thoft, N.B.; Andersen, H.H.; Sarholt-Kristensen, L.

    1993-01-01

    Ion implantation of pure aluminium with thallium induces the formation of nanosized crystalline inclusions of thallium with a f.c.c. structure. The size of the inclusions depends on the implantation conditions and subsequent annealing treatments and is typically in the range from 1 to 10 nm. The inclusions are aligned topotactically with the aluminium matrix with a cube-cube orientation relationship and they have a truncated octahedral shape bounded by {111} and {001} planes. The lattice parameter of the f.c.c. thallium inclusions is 0.484 ± 0.002 nm, which is slightly but significantly larger than in the high-pressure f.c.c. thallium phase known to be stable above 3.8 GPa. (Author)

  5. Nanosized Minicells Generated by Lactic Acid Bacteria for Drug Delivery

    Directory of Open Access Journals (Sweden)

    Huu Ngoc Nguyen

    2017-01-01

    Full Text Available Nanotechnology has the ability to target specific areas of the body, controlling the drug release and significantly increasing the bioavailability of active compounds. Organic and inorganic nanoparticles have been developed for drug delivery systems. Many delivery systems are through clinical stages for development and market. Minicell, a nanosized cell generated by bacteria, is a potential particle for drug delivery because of its size, safety, and biodegradability. Minicells produced by bacteria could drive therapeutic agents against cancer, microbial infection, and other diseases by targeting. In addition, minicells generated by lactic acid bacteria being probiotics are more interesting than others because of their benefits like safety, immunological improvement, and biodegradation. This review aims to highlight the stages of development of nanoparticle for drug delivery and discuss their advantages and limitations to clarify minicells as a new opportunity for the development of potential nanoparticle for drug delivery.

  6. Calculation of the local electric field for an infinite array of conducting nanosized objects

    International Nuclear Information System (INIS)

    Lim, Mikyoung; Kim, Dohyung; Kim, Sang Youl; Bouree, Jean-Eric

    2007-01-01

    The electric field for an infinite array of conducting nanosized objects in two-dimensional space has been calculated. The mirror symmetry for this physical problem has been introduced. By taking into account this symmetry, we transform the original problem into an infinite two-dimensional array of nanosized objects with the same solution. The electric field equation of the model has been successfully constructed using a single-layer potential of the periodic Green function. The electric field operator has been introduced. This mathematical approach yields a solution for determining the optimum structure of nanosized electronic devices such as carbon nanotube-based field emitters

  7. The enhanced photoactivity of nanosized Bi2WO6 catalyst for the degradation of 4-chlorophenol

    International Nuclear Information System (INIS)

    Fu Hongbo; Yao Wenqing; Zhang Liwu; Zhu Yongfa

    2008-01-01

    Nanosized Bi 2 WO 6 catalyst exhibited the enhanced photoactivity for the degradation of 4-chlorophenol (4-CP) under visible irradiation compared to the sample prepared by high-temperature solid reaction. The photoactivity of the catalyst was sensitive to pH variation of the suspension. Nanosized Bi 2 WO 6 catalyst showed the highest activity at pH 7.2. The photodegradation of 4-CP by nanosized Bi 2 WO 6 catalyst followed a pseudo-first-order reaction. After three recycling runs for the photodegradation of 4-CP, the activity of the catalyst did not show any significant loss, suggesting that the catalyst was stable under visible irradiation

  8. Nanosized metal deposits on titanium dioxide for augmenting gas-phase toluene photooxidation

    Science.gov (United States)

    Lee, Sooi Li; Scott, Jason; Chiang, Ken; Amal, Rose

    2009-01-01

    The build-up of intermediate species on the surface of TiO2 during gas-phase toluene (C7H8) photodegradation has been observed to deactivate the photocatalyst. Nanosized metallic deposits on the TiO2 surface may enhance the photocatalytic process and improve photocatalyst performance. In this study, noble (Ag, Au) and platinum group (Pt, Pd, Rh) metals, at a nominal loading of 0.5 at.%, were deposited onto Degussa P25 TiO2 to enhance photocatalyst performance and inhibit deactivation. Pd, Rh and Au deposits delayed photocatalyst deactivation by a factor of 2, while Pt deposits delayed photocatalyst deactivation by a factor of 20, when compared with neat TiO2. Ag deposits did not improve photocatalyst activity. Metal deposit performance was related to the work function of each metal, however, the Pt finding suggested that these effects are not governed solely by this aspect, but factors such as deposit characteristics and/or thermal catalytic properties of the metals may be influential.

  9. New nanosized catalytic membrane reactors for hydrogenation with stored hydrogen: Prerequisites and the experimental basis for their creation

    Science.gov (United States)

    Soldatov, A. P.; Tsodikov, M. V.; Parenago, O. P.; Teplyakov, V. V.

    2010-12-01

    The prerequisites and prospects for creating a new generation of nanosized membrane reactors are considered. For the first time, hydrogenation reactions take place in ceramic membrane pores with hydrogen adsorbed beforehand in mono- and multilayered oriented carbon nanotubes with graphene walls (OCNTGs) formed on the internal pore surface. It is shown for Trumem microfiltration membranes with D avg ˜130 nm that oxidation reactions of CO on a Cu0.03Ti0.97O2 ± δ catalyst and the oxidative conversion of methane into synthesis gas and light hydrocarbons on La + Ce/MgO are considerably enhanced when they occur in membranes. Regularities of hydrogen adsorption, storage, and desorption in nanosized membrane reactors are investigated through OCNTG formation in Trumem ultrafiltration membrane pores with D avg = 50 and 90 nm and their saturation with hydrogen at a pressure of 10-13 MPa. It is shown that the amount of adsorbed hydrogen reaches 14.0% of OCNTG mass. Using thermogravimetric analysis in combination with mass-spectrometric analysis, hydrogen adsorption in OCNTG is first determined and its desorption is found to proceed at atmospheric pressure at a temperature of ˜175°C. It is shown that adsorbed hydrogen affects the transport properties of the membranes, reducing their efficiency with respect to liquids by 4-26 times. This is indirect confirmation of its high activity, due apparently the dissociative mechanism of adsorption.

  10. Noncatalytic hydrogenation of decene-1 with hydrogen accumulated in a hybrid carbon nanostructure in nanosized membrane reactors

    Science.gov (United States)

    Soldatov, A. P.

    2014-08-01

    Studies on the creation of nanosized membrane reactors (NMRs) of a new generation with accumulated hydrogen and a regulated volume of reaction zone were continued at the next stage. Hydrogenation was performed in the pores of ceramic membranes with hydrogen preliminarily adsorbed in mono- and multilayered orientated carbon nanotubes with graphene walls (OCNTGs)—a new hybrid carbon nanostructure formed on the inner pore surface. Quantitative determination of hydrogen adsorption in OCNTGs was performed using TRUMEM ultrafiltration membranes with D av = 50 and 90 nm and showed that hydrogen adsorption was up to ˜1.5% of the mass of OCNTG. The instrumentation and procedure for noncatalytic hydrogenation of decene-1 at 250-350°C using hydrogen accumulated and stored in OCNTG were developed. The conversion of decene-1 into decane was ˜0.2-1.8% at hydrogenation temperatures of 250 and 350°C, respectively. The rate constants and activation energy of hydrogenation were determined. The latter was found to be 94.5 kJ/mol, which is much smaller than the values typical for noncatalytic hydrogenations and very close to the values characteristic for catalytic reactions. The quantitative distribution of the reacting compounds in each pore regarded as a nanosized membrane reactor was determined. The activity of hydrogen adsorbed in a 2D carbon nanostructure was evaluated. Possible mechanisms of noncatalytic hydrogenation were discussed.

  11. Structural and Spectroscopic Characterization of A Nanosized Sulfated TiO2 Filler and of Nanocomposite Nafion Membranes

    Directory of Open Access Journals (Sweden)

    Valentina Allodi

    2016-03-01

    Full Text Available A large number of nano-sized oxides have been studied in the literature as fillers for polymeric membranes, such as Nafion®. Superacidic sulfated oxides have been proposed and characterized. Once incorporated into polymer matrices, their beneficial effect on peculiar membrane properties has been demonstrated. The alteration of physical-chemical properties of composite membranes has roots in the intermolecular interaction between the inorganic filler surface groups and the polymer chains. In the attempt to tackle this fundamental issue, here we discuss, by a multi-technique approach, the properties of a nanosized sulfated titania material as a candidate filler for Nafion membranes. The results of a systematic study carried out by synchrotron X-ray diffraction, transmission electron microscopy, thermogravimetry, Raman and infrared spectroscopies are presented and discussed to get novel insights about the structural features, molecular properties, and morphological characteristics of sulphated TiO2 nanopowders and composite Nafion membranes containing different amount of sulfated TiO2 nanoparticles (2%, 5%, 7% w/w.

  12. Nanosized Thin SnO2 Layers Doped with Te and TeO2 as Room Temperature Humidity Sensors

    Directory of Open Access Journals (Sweden)

    Biliana Georgieva

    2014-05-01

    Full Text Available In this paper the humidity sensing properties of layers prepared by a new method for obtaining doped tin oxide are studied. Different techniques—SEM, EDS in SEM, TEM, SAED, AES and electrical measurements—are used for detailed characterization of the thin layers. The as-deposited layers are amorphous with great specific area and low density. They are built up of a fine grained matrix, consisting of Sn- and Te-oxides, and a nanosized dispersed phase of Te, Sn and/or SnTe. The chemical composition of both the matrix and the nanosized particles depends on the ratio RSn/Te and the evaporation conditions. It is shown that as-deposited layers with RSn/Te ranging from 0.4 to 0.9 exhibit excellent characteristics as humidity sensors operating at room temperature—very high sensitivity, good selectivity, fast response and short recovery period. Ageing tests have shown that the layers possess good long-term stability. Results obtained regarding the type of the water adsorption on the layers’ surface help better understand the relation between preparation conditions, structure, composition and humidity sensing properties.

  13. A novel nano-sized bionic function interface for enhancing the ability of red blood cells to carry oxygen

    International Nuclear Information System (INIS)

    Wang, Y.-H.; Guo, J.-W.; Gu, H.-Y.

    2010-01-01

    A nano-sized bionic function interface was prepared by immobilizing red blood cells onto a silver electrode, which was modified with cysteamine and colloidal gold. Scanning electron microscopy and electrochemical impedance spectroscopy were used to characterize its surface. Cyclic voltammograms in phosphate buffer solution of pH 7.0 exhibited a pair of redox peaks for oxygen at -378 and -207 mV, respectively. The reduction peak currents at -378 mV were linearly proportional to the oxygen concentration in the range from 12.6 μM to 1.39 mM. Cyclic voltammetry also indicated that the functional surface enhanced the ability of red blood cells to transport oxygen. (author)

  14. Mn 3 O 4 nano-sized crystals: Rapid synthesis and extension to ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 126; Issue 3. Mn3O4 nano-sized crystals: Rapid synthesis and extension to preparation of nanosized LiMn2O4 materials. Xiao-Ling Cui Yong-Li Li Shi-You Li Guo-Cun Sun Jin-Xia Ma Lu Zhang Tian-Ming Li Rong-Bo Ma. Regular Articles Volume 126 Issue 3 May ...

  15. Siderophores, the answer for micro to nanosized asbestos fibre related health hazard

    Science.gov (United States)

    Bhattacharya, Shabori; Ledwani, Lalita; John, P. J.

    2016-04-01

    Recent studies on the potential toxicity of High Aspect Ratio Nanoparticles (HARN) has yet once again reinforced the health hazard imposed by asbestos fibres ranging from nano to micro size. Asbestos a naturally occurring fibrous mineral declared a Group I definite carcinogen by IARC (International Agency for Research on Cancer), a unit of WHO in the year 1987, has been extensively used since World War II to the near past for various commercial products. According to the most recent World Health Organization (WHO) estimates, asbestos-related diseases, resulting from exposure at workplace claims more than 107000 lives every year worldwide. The various types of toxic effects induced by asbestos in humans include - i) inflammation and fibrogenesis of lung, ii) mesothelioma iii) asbestosis and iv) bronchogenic carcinoma. The stability of asbestos in natural environment and its biological aggressiveness is related to their fibrous structure and dimensions. The actual risk associated with the exposure to nanosized asbestos, which is still unknown and escapes most regulations worldwide, has been shown in various toxicity assessment studies conducted on various animal models.In an effort to reduce the size of asbestos and therby its toxicity by limiting its biopersistence, oxalic acid treatment of asbestos coupled to power ultrasound treatment was carried out. The nanosized particles formed were still found to retain their hazardous effect. Similar were the results obtained on strong acid treatment of asbestos as well. A probable solution to the asbestos toxicity problem therefore envisaged was bioremediation. This involved the secretion of iron chelating molecules termed siderophores by microbes, which are of significance due to their ability to form very stable and soluble complexes with iron. Iron in asbestos composition is a major factor responsible for its carcinogenicity, removal or extraction of which would prove to be an effective answer to the worldwide problem

  16. Investigation of the conversion mechanism of nanosized CoF2

    International Nuclear Information System (INIS)

    Teng, Yin Ting; Pramana, Stevin S.; Ding, Junfeng; Wu, Tom; Yazami, Rachid

    2013-01-01

    Highlights: • First report on synthesis of nanosized cobalt fluoride via precipitation. • CoF x formation during recharging commences at the interface between cobalt and lithium fluoride. • Valance change of cobalt in cobalt fluoride electrode upon discharging and recharging is shown from EELS and XPS. • Lithiation of CoF 2 leads to formation of superparamagnetic nanosized cobalt particles. • Morphology of the conductive carbon addictives used plays a crucial factor in determining the capacity retention ability. -- Abstract: Nanoparticles (∼20 nm) of tetragonal (P42/mnm) cobalt fluoride (CoF 2 ) has been synthesized by precipitation using cobalt nitrate and ammonium fluoride solution at room temperature, followed by annealing at 400 °C under argon atmosphere. The morphology and structure have been studied by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). The electrochemical lithiation of CoF 2 and its structural and valence changes during conversion have been investigated. Electrochemical measurements revealed a discharge specific capacity close to theoretical specific capacity of 553 mAh g −1 and charge specific capacities ranging from 250 to 450 mAh g −1 in the first cycle, depending on the type of conductive carbon addictive used. Lithiation of CoF 2 occurs without any intercalation, but via conversion reaction CoF 2 + 2Li + + 2e − → Co(0) + 2LiF. During lithiation, CoF 2 is fully reduced to Co(0) and breaks down into smaller particles of ∼2 nm. Upon recharging, CoF x is formed instead of CoF 2 . XPS and EELS studies show that only the surface of the electrode is reconverted back to CoF x during recharging. In addition, recharging to form CoF x commences at the interface between the cobalt and lithium fluoride. These results offer the experimental evidence explaining the lack of cycle stability of metal fluorides that undergo a conversion reaction with lithium such

  17. Nano-sized ceramic particles of hydroxyapatite calcined with an anti-sintering agent.

    Science.gov (United States)

    Okada, Masahiro; Furuzono, Tsutomu

    2007-03-01

    Nano-sized crystals of calcined hydroxyapatite (HAp) having spherical morphologies were fabricated by calcination at 800 degrees C for 1 h with an anti-sintering agent surrounding the original HAp particles and the agent was subsequently removed by washing after calcination. The original HAp particles were prepared by a modified emulsion system, and surrounded with poly(acrylic acid, calcium salt) (PAA-Ca) by utilizing a precipitation reaction between calcium hydroxide and poly(acrylic acid) adsorbed on the HAp particle surfaces in an aqueous medium. In the case of calcination without PAA-Ca, micron-sized particles consisting of sintered polycrystals were mainly observed by scanning electron microscopy, indicating the calcination-induced sintering among the crystals. On the other hand, most of the crystals calcined with the anti-sintering agent were observed as isolated particles, and the mean size of the HAp crystals was around 80 nm. This result indicates that PAA-Ca and its thermally decomposed product, CaO, surrounding the HAp crystals could protect them against calcination-induced sintering during calcination at 800 degrees C. The HAp crystals calcined with PAA-Ca showed high crystallinity, and no other calcium phosphate phases could be detected.

  18. Effect of Nitrogen Oxides on Elemental Mercury Removal by Nanosized Mineral Sulfide.

    Science.gov (United States)

    Li, Hailong; Zhu, Lei; Wang, Jun; Li, Liqing; Lee, Po-Heng; Feng, Yong; Shih, Kaimin

    2017-08-01

    Because of its large surface area, nanosized zinc sulfide (Nano-ZnS) has been demonstrated in a previous study to be efficient for removal of elemental mercury (Hg 0 ) from coal combustion flue gas. The excellent mercury adsorption performance of Nano-ZnS was found to be insusceptible to water vapor, sulfur dioxide, and hydrogen chloride. However, nitrogen oxides (NO X ) apparently inhibited mercury removal by Nano-ZnS; this finding was unlike those of many studies on the promotional effect of NO X on Hg 0 removal by other sorbents. The negative effect of NO X on Hg 0 adsorption over Nano-ZnS was systematically investigated in this study. Two mechanisms were identified as primarily responsible for the inhibitive effect of NO X on Hg 0 adsorption over Nano-ZnS: (1) active sulfur sites on Nano-ZnS were oxidized to inactive sulfate by NO X ; and (2) the chemisorbed mercury, i.e., HgS, was reduced to Hg 0 by NO X . This new insight into the role of NO X in Hg 0 adsorption over Nano-ZnS can help to optimize operating conditions, maximize Hg 0 adsorption, and facilitate the application of Nano-ZnS as a superior alternative to activated carbon for Hg 0 removal using existing particulate matter control devices in power plants.

  19. Mesoporous Silica Thin Membranes with Large Vertical Mesochannels for Nanosize-Based Separation.

    Science.gov (United States)

    Liu, Yupu; Shen, Dengke; Chen, Gang; Elzatahry, Ahmed A; Pal, Manas; Zhu, Hongwei; Wu, Longlong; Lin, Jianjian; Al-Dahyan, Daifallah; Li, Wei; Zhao, Dongyuan

    2017-09-01

    Membrane separation technologies are of great interest in industrial processes such as water purification, gas separation, and materials synthesis. However, commercial filtration membranes have broad pore size distributions, leading to poor size cutoff properties. In this work, mesoporous silica thin membranes with uniform and large vertical mesochannels are synthesized via a simple biphase stratification growth method, which possess an intact structure over centimeter size, ultrathin thickness (≤50 nm), high surface areas (up to 1420 m 2 g -1 ), and tunable pore sizes from ≈2.8 to 11.8 nm by adjusting the micelle parameters. The nanofilter devices based on the free-standing mesoporous silica thin membranes show excellent performances in separating differently sized gold nanoparticles (>91.8%) and proteins (>93.1%) due to the uniform pore channels. This work paves a promising way to develop new membranes with well-defined pore diameters for highly efficient nanosize-based separation at the macroscale. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. ELECTROPHORETICALLY DEPOSITED NANOSIZED HYDROXYAPATITE COATINGS ON 316LVM STAINLESS STEEL FOR ORTHOPAEDIC IMPLANTS

    Directory of Open Access Journals (Sweden)

    MARIJA MIHAILOVIĆ

    2011-03-01

    Full Text Available Hydroxyapatite is a widely used bioceramic material in implant coatings research because of its bioactive behavior when being deposited onto the metallic implant and compatibility with the human bones composition. The coating of nanosized hydroxyapatite was electrophoretically deposited on a blasted surface of stainless steel 316LVM samples at constant voltage, for different deposition times and subsequently sintered in both, vacuum and argon atmosphere, at 1040 and 1000 °C, respectively. Although sintering temperatures needed to achieve highly dense coatings can cause HAp coating phase changes, the possibility to obtain a bioactive coating on 316LVM substrate, without the coatings phase changes due to the nature of the used stoichiometric nanostructured hydroxyapatite is presented in this work. The thermal stability of the used HAp powder was assessed by DTA-TG analyses over the temperature range of 23-1000 C, i.e., at the or nearby experimental sintering temperature. The microstructure characterization was accomplished using SEM, while phase composition was determined using XRD.

  1. Hydrophobic Nanosized All-Silica Beta Zeolite: Efficient Synthesis and Adsorption Application.

    Science.gov (United States)

    Zhu, Zhiguo; Xu, Hao; Jiang, Jingang; Wu, Haihong; Wu, Peng

    2017-08-16

    All-silica beta zeolite, synthesized by conventional hydroxide route, usually possesses small crystal size of a few hundred nanometers but poor hydrophobicity, whereas the fluoride-mediated one exhibits to be highly hydrophobic but microsized. To obtain nanosized all-silica beta zeolite with excellent hydrophobicity, an innovative and efficient hydrothermal route via interzeolite transformation for synthesizing all-silica beta zeolite is proposed in present study. With the assistance of beta seeds and tetraethylammonium hydroxide as the structure-directing agent, siliceous beta zeolite is well-crystallized at a high solid yield via dissolution-recrystallization of all-silica ITQ-1 crystals at an extremely low water content (H 2 O/SiO 2 molar ratio of 1). The obtained all-silica beta crystals are composed of 30-70 nm nanoparticles and highly hydrophobic just next to siliceous beta-F zeolite synthesized by environmentally unfriendly fluoride route, which is derived from relatively small amounts of internal defect sites. Thus, this beta zeolite is superior to other pure silica beta zeolites in the adsorption of large-sized volatile organic compounds (VOCs), which is mainly attributed to its high total pore volume and specific surface area as well as excellent hydrophobicity.

  2. Influence of Nanosized Silicon Oxide on the Luminescent Properties of ZnO Nanoparticles

    Directory of Open Access Journals (Sweden)

    Vitaliy Shvalagin

    2016-01-01

    Full Text Available For practical use of nanosized zinc oxide as the phosphor its luminescence quantum yields should be maximized. The aim of this work was to enhance luminescent properties of ZnO nanoparticles and obtain high-luminescent ZnO/SiO2 composites using simpler approaches to colloidal synthesis. The luminescence intensity of zinc oxide nanoparticles was increased about 3 times by addition of silica nanocrystals to the source solutions during the synthesis of ZnO nanoparticles. Then the quantum yield of luminescence of the obtained ZnO/SiO2 composites is more than 30%. Such an impact of silica is suggested to be caused by the distribution of ZnO nanocrystals on the surface of silica, which reduces the probability of separation of photogenerated charges between the zinc oxide nanoparticles of different sizes, and as a consequence, there is a significant increase of the luminescence intensity of ZnO nanoparticles. This way of increasing nano-ZnO luminescence intensity facilitates its use in a variety of devices, including optical ultraviolet and visible screens, luminescent markers, antibacterial coatings, luminescent solar concentrators, luminescent inks for security printing, and food packaging with abilities of informing consumers about the quality and safety of the packaged product.

  3. Aloe vera Induced Biomimetic Assemblage of Nucleobase into Nanosized Particles

    Science.gov (United States)

    Chauhan, Arun; Zubair, Swaleha; Sherwani, Asif; Owais, Mohammad

    2012-01-01

    Aim Biomimetic nano-assembly formation offers a convenient and bio friendly approach to fabricate complex structures from simple components with sub-nanometer precision. Recently, biomimetic (employing microorganism/plants) synthesis of metal and inorganic materials nano-particles has emerged as a simple and viable strategy. In the present study, we have extended biological synthesis of nano-particles to organic molecules, namely the anticancer agent 5-fluorouracil (5-FU), using Aloe vera leaf extract. Methodology The 5-FU nano- particles synthesized by using Aloe vera leaf extract were characterized by UV, FT-IR and fluorescence spectroscopic techniques. The size and shape of the synthesized nanoparticles were determined by TEM, while crystalline nature of 5-FU particles was established by X-ray diffraction study. The cytotoxic effects of 5-FU nanoparticles were assessed against HT-29 and Caco-2 (human adenocarcinoma colorectal) cell lines. Results Transmission electron microscopy and atomic force microscopic techniques confirmed nano-size of the synthesized particles. Importantly, the nano-assembled 5-FU retained its anticancer action against various cancerous cell lines. Conclusion In the present study, we have explored the potential of biomimetic synthesis of nanoparticles employing organic molecules with the hope that such developments will be helpful to introduce novel nano-particle formulations that will not only be more effective but would also be devoid of nano-particle associated putative toxicity constraints. PMID:22403622

  4. Synthesis and Characterization of Nanosized Fe2O3 Pigments

    Directory of Open Access Journals (Sweden)

    M. F. R. Fouda

    2012-01-01

    Full Text Available The work in this paper was devoted to investigating some nanosized iron oxide pigments prepared by microemulsion technique. The role of concentration of iron salt and surfactant (cetyltrimethylammonium bromide on the produced iron oxide was studied. The techniques employed to characterize the samples were thermogravimetric analysis, X-ray diffractometry, transmission electron microscope, infrared spectroscopy, and diffuse reflectance spectroscopy. The results revealed that the particle size of the prepared sample using 0.2 M iron sulfate and 3.2 wt% of surfactant was in the range 7–9 nm. Increasing the concentration of either iron salt or the surfactant increased the particle size of the obtained ferric oxide. The diffuse reflectance measurements showed that the charge transfer/electron pair transition absorption peak, which is closely related to the reddish color of the oxide, was shifted to a longer wavelength (blue shift by decreasing the dimension of the particles. The samples were tested as pigments. They showed different tints of red color and were found to be promising for applications as pigments in the field of paint manufacturing.

  5. Aloe vera induced biomimetic assemblage of nucleobase into nanosized particles.

    Science.gov (United States)

    Chauhan, Arun; Zubair, Swaleha; Sherwani, Asif; Owais, Mohammad

    2012-01-01

    Biomimetic nano-assembly formation offers a convenient and bio friendly approach to fabricate complex structures from simple components with sub-nanometer precision. Recently, biomimetic (employing microorganism/plants) synthesis of metal and inorganic materials nano-particles has emerged as a simple and viable strategy. In the present study, we have extended biological synthesis of nano-particles to organic molecules, namely the anticancer agent 5-fluorouracil (5-FU), using Aloe vera leaf extract. The 5-FU nano- particles synthesized by using Aloe vera leaf extract were characterized by UV, FT-IR and fluorescence spectroscopic techniques. The size and shape of the synthesized nanoparticles were determined by TEM, while crystalline nature of 5-FU particles was established by X-ray diffraction study. The cytotoxic effects of 5-FU nanoparticles were assessed against HT-29 and Caco-2 (human adenocarcinoma colorectal) cell lines. Transmission electron microscopy and atomic force microscopic techniques confirmed nano-size of the synthesized particles. Importantly, the nano-assembled 5-FU retained its anticancer action against various cancerous cell lines. In the present study, we have explored the potential of biomimetic synthesis of nanoparticles employing organic molecules with the hope that such developments will be helpful to introduce novel nano-particle formulations that will not only be more effective but would also be devoid of nano-particle associated putative toxicity constraints.

  6. The Synthesis and Modification of Nanosized Clickable Latex Particles

    KAUST Repository

    Almahdali, Sarah

    2013-05-01

    This research aims to add to the current knowledge available for miniemulsion polymerization reactions and to use this knowledge to synthesize multifunctional nanosized latex particles that have the potential to be used in catalysis. The physical properties of the latex can be adjusted to suit various environments due to the multiple functional groups present. For this research, styrene, pentafluorostyrene, azidomethyl styrene, pentafluorostyrene with azidomethyl styrene and pentafluorostyrene with styrene latexes were produced, and analyzed by dynamic light scattering. The latexes were synthesized using a miniemulsion polymerization technique found through this research. Potassium oleate and potassium 1,1,2,2,3,3,4,4-nonafluorobutane-1-sulfonate were used as surfactants during the miniemulsion polymerization reaction to synthesize pentafluorostyrene with azidomethyl styrene latex. Transmission electron microscopy data and dynamic light scattering data have been collected to analyze the structure of this latex, and it has been synthesized using a number of conditions, differing in reaction time, surfactant amount and sonication methods. We have also improved the solubility of the latex through a copper(I) catalyzed 1,3-dipolar azide-alkyne reaction, by clicking (polyethylene glycol)5000 onto the azide functional groups.

  7. Superfocusing the light through the nanosize slit via photonic tornado

    Science.gov (United States)

    Choi, Seong Soo; Jha, Vinaya; Suwal, Om; Park, Myoung Jin; Park, Nam Kyu; Kim, Daisik

    2010-03-01

    The macro size pyramidal horn probe such as klystron horn antenna has been used to provide the excellent focusing capabilities in microwave region. In the similar way, the pyramidal probe with the micron size mirror (pyramidal horn probe) has been fabricated with a nano-size aperture with diameter ranging from ˜1 nm to ˜30 nm. Light transmission through the micro-fabricated pyramidal horn probe has been measured to enhance the light transmission due to resonant effects between the cavity mode and the slit modes in the probe, along with improved directionality of the transmitted beam. The resonant tunneling between two standing waves in the input groove and in the output groove can provide the transmission enhancements. With decreasing slit width, the transmission is found to increasing tremendously.[1] The transmission is measured to be inversely proportional to the area.[2,3] References:[1] R. Gordon, Phys. Rev. B 73, 153405 (2006).[2] R. Harrington, IEEE Trans. Antennas Propagat. Ap-30, 205(1982).[3] Y Leviatan, R. Harrington, J. Maut, IEEE Trans. Antennas Propagat. Ap-30, 1533(1982)

  8. Nano-Se Assimilation and Action in Poultry and Other Monogastric Animals: Is Gut Microbiota an Answer?

    Science.gov (United States)

    Surai, Peter F.; Kochish, Ivan I.; Velichko, Oksana A.

    2017-12-01

    Recently, a comprehensive review paper devoted to roles of nano-Se in livestock and fish nutrition has been published in the Nanoscale Research Letters. The authors described in great details an issue related to nano-Se production and its possible applications in animal industry and medicine. However, molecular mechanisms of nano-Se action were not described and the question of how nano-Se is converted into active selenoproteins is not resolved. It seems likely that the gut microbiota can convert nano-Se into selenite, H2Se or Se-phosphate with the following synthesis of selenoproteins. This possibility needs to be further studied in detail, and advantages and disadvantages of nano-Se as a source of Se in animal/poultry/fish nutrition await critical evaluations.

  9. Neuro-oncologic applications of exosomes, microvesicles, and other nano-sized extracellular particles.

    Science.gov (United States)

    Gonda, David D; Akers, Johnny C; Kim, Ryan; Kalkanis, Steven N; Hochberg, Fred H; Chen, Clark C; Carter, Bob S

    2013-04-01

    The discovery that tumor-derived proteins and nucleic acids can be detected in nano-sized vesicles in the plasma and cerebrospinal fluid of patients afflicted with brain tumors has expanded opportunities for biomarker and therapeutic discovery. Through delivery of their contents to surrounding cells, exosomes, microvesicles, and other nano-sized extracellular vesicles secreted by tumors modulate their environment to promote tumor growth and survival. In this review, we discuss the biological processes mediated by these extracellular vesicles and their applications in terms of brain tumor diagnosis, monitoring, and therapy. We review the normal physiology of these extracellular vesicles, their pertinence to tumor biology, and directions for research in this field.

  10. Nanosizing a Metal-Organic Framework Enzyme Carrier for Accelerating Nerve Agent Hydrolysis.

    Science.gov (United States)

    Li, Peng; Moon, Su-Young; Guelta, Mark A; Lin, Lu; Gómez-Gualdrón, Diego A; Snurr, Randall Q; Harvey, Steven P; Hupp, Joseph T; Farha, Omar K

    2016-10-05

    We report the synthesis and characterization of a water-stable zirconium metal-organic framework (MOF), NU-1003, featuring the largest mesoporous aperture known for a zirconium MOF. This material has been used to immobilize the nerve agent hydrolyzing enzyme, organophosphorus acid anhydrolase (OPAA). The catalytic efficiency of immobilized OPAA in nanosized NU-1003 is significantly increased compared to that of OPAA immobilized in microsized NU-1003 and even exceeds that of the free OPAA enzyme. This paper highlights a method for rapid and highly efficient hydrolysis of nerve agents using nanosized enzyme carriers.

  11. Chemoselective Oxidation of Bio-Glycerol with Nano-Sized Metal Catalysts

    DEFF Research Database (Denmark)

    Li, Hu; Kotni, Ramakrishna; Zhang, Qiuyun

    2015-01-01

    to selectively oxidize glycerol and yield products with good selectivity is the use of nano-sized metal particles as heterogeneous catalysts. In this short review, recent developments in chemoselective oxidation of glycerol to specific products over nano-sized metal catalysts are described. Attention is drawn...... to various reaction parameters such as the type of the support, the size of the metal particles, and the acid/base properties of the reaction medium which were illustrated to largely influence the activity of the nanocatalyst and selectivity to the target product. - See more at: http...

  12. Electrochemical Li-uptake properties of nanosized NiSb2 prepared by solvothermal route

    International Nuclear Information System (INIS)

    Xie, J.; Zhao, X.B.; Cao, G.S.; Zhao, M.J.; Su, S.F.

    2005-01-01

    The nanosized intermetallic compound NiSb 2 was prepared by a solvothermal route and studied as a potential anode material for secondary lithium-ion batteries. The microstructure of the as-prepared NiSb 2 powder was characterized by X-ray diffraction, transmission electron microscopy. The electrochemical performances of the NiSb 2 electrode were investigated by galvanostatic charge and discharge cycling and by cyclic voltammogram. It was found that the nanosized NiSb 2 electrode shows improved cycling behavior, especially in the initial cycles, compared to the micrometer sized NiSb 2 prepared by a levitation-melting/ball-milling route

  13. Biological consequences from interaction of nanosized titanium(iv) oxides with defined human blood components

    Science.gov (United States)

    Stella, Aaron

    The utility of engineered nanomaterials is growing, particularly the titanium(iv) oxide (titanium dioxide, TiO2) nanoparticles. TiO 2 is very useful for brightening paints, and coloring foods. Nano-sized TiO2 is also useful for sunscreens, cosmetics, and can be utilized as a photocatalyst. However, the nanometer size of the TiO2 nanoparticle is a characteristic that may contribute oxidative stress to red blood cells (RBCs) in humans. This study utilized screening methods to evaluate different forms of TiO2 nanoparticles which differ by primary particle size, specific surface area, crystalline phase, and surface polarity. RBCs are rich in the intracellular antioxidant glutathione (GSH). HPLC analysis revealed that some TiO2 nanoparticles caused oxidation of GSH to glutathione disulfide (GSSG). Vitamin E is a major membrane-bound antioxidant. Vitamin E levels were then determined by HPLC in the RBC membrane after exposure to TiO2 nanoparticles. The HPLC results showed that each nanoparticle oxidized RBC glutathione and membrane vitamin E at different rates. When hemoglobin was mixed with each TiO2 nanoparticle, hemoglobin was adsorbed at varying rates to the surface of the nanoparticles. Similarly, the aminothiol homocysteine was also adsorbed at different rates by the TiO2 nanoparticles. Using light microscopy, some TiO2 nanoparticles caused the formation of RBC aggregates which significantly changed the RBC morphology. The aggregation data was quantified using a hemacytometer. The TiO2 nanoparticles also caused hemolysis of RBCs. Hemolysis is considered to be a toxic endpoint for RBCs. Changes in the nucleated lymphocyte gene expression of certain oxidative stress genes were also observed using real-time polymerase chain reaction (qPCR). The data indicates that RBCs can ultimately be hemolyzed by biological oxidative damage resulting from a combination of oxidative mechanisms. Additionally, the TiO2 nanoparticles demonstrated the ability to adsorb biomolecules to

  14. Improving the electrochemical properties of nanosized LiFePO4-based electrode by boron doping

    International Nuclear Information System (INIS)

    Trócoli, Rafael; Franger, Sylvain; Cruz, Manuel; Morales, Julián; Santos-Peña, Jesús

    2014-01-01

    Highlights: • Thermal treatment of boron phosphate with LiFePO 4 provides electrode materials with high performance in lithium half-cells: 160 mAh·g -1 (90% of theoretical capacity) under C/5 rate • The products are composites containing boron-modified LiFePO 4 , FePO 4 and an amorphous phase with ionic diffusion properties • The boron treatment affects textural, conductive and lithium diffusivity of the electrode material leading to higher performance • A limited boron-doping of the phospholivine structure is observed - Abstract: Electrode materials with homogeneous distribution of boron were obtained by heating mixtures of nanosized carbon-coated lithium iron phosphate and BPO 4 in 3-9% weight at 700 °C. The materials can be described as nanocomposites containing i) LiFePO 4 , possibly doped with a low amount of boron, ii) FePO 4 and iii) an amorphous layer based on Li 4 P 2 O 7 -derived material that surrounds the phosphate particles. The thermal treatment with BPO 4 also triggered changes in the carbon coating graphitic order. Galvanostatic and voltammetric studies in lithium half-cells showed smaller polarisation, higher capacity and better cycle life for the boron-doped composites. For instance, one of the solids, called B 6 -LiFePO 4 , provided close to 150 and 140 mAhg -1 (87% and 81% of theoretical capacity, respectively) under C/2.5 and C regimes after several cycles. Improved specific surface area, carbon graphitization, conductivity and lithium ion diffusivity in the boron-doped phospholivine network account for this excellent rate performance. The properties of an amorphous layer surrounding the phosphate particles also account for such higher performance

  15. Characterization of food-grade titanium dioxide: the presence of nanosized particles.

    Science.gov (United States)

    Yang, Yu; Doudrick, Kyle; Bi, Xiangyu; Hristovski, Kiril; Herckes, Pierre; Westerhoff, Paul; Kaegi, Ralf

    2014-06-03

    Titanium dioxide (TiO2) is widely used in food products, which will eventually enter wastewater treatment plants and terrestrial or aquatic environments, yet little is known about the fraction of this TiO2 that is nanoscale, or the physical and chemical properties of TiO2 that influence its human and environmental fate or toxicity. Instead of analyzing TiO2 properties in complex food or environmental samples, we procured samples of food-grade TiO2 obtained from global food suppliers and then, using spectroscopic and other analytical techniques, quantified several parameters (elemental composition, crystal structure, size, and surface composition) that are reported to influence environmental fate and toxicity. Another sample of nano-TiO2 that is generally sold for catalytic applications (P25) and widely used in toxicity studies, was analyzed for comparison. Food-grade and P25 TiO2 are engineered products, frequently synthesized from purified titanium precursors, and not milled from bulk scale minerals. Nanosized materials were present in all of the food-grade TiO2 samples, and transmission electron microscopy showed that samples 1-5 contained 35, 23, 21, 17, and 19% of nanosized primary particles (average hydrodynamic diameter of >100 nm. Food-grade samples contained phosphorus (P), with concentrations ranging from 0.5 to 1.8 mg of P/g of TiO2. The phosphorus content of P25 was below inductively coupled plasma mass spectrometry detection limits. Presumably because of a P-based coating detected by X-ray photoelectron spectroscopy, the ζ potential of the food-grade TiO2 suspension in deionized water ranged from -10 to -45 mV around pH 7, and the iso-electric point for food-grade TiO2 (grade materials, and although the presence of amorphous TiO2 could not be ruled out, it is unlikely on the basis of Raman analysis. The food-grade TiO2 was solar photoactive. Cationic dyes adsorbed more readily to food-grade TiO2 than P25, indicating very different potentials for

  16. Preparation and characterization of uniform nanosized cephradine by combination of reactive precipitation and liquid anti-solvent precipitation under high gravity environment.

    Science.gov (United States)

    Zhong, Jie; Shen, Zhigang; Yang, Yan; Chen, Jianfeng

    2005-09-14

    In this work, a novel direct method, which was combined with reactive precipitation and liquid anti-solvent precipitation under high gravity environment, had been developed to prepare nanosized cephradine with narrow particle size distribution. Compared with commercial crude cephradine, the prepared cephradine showed a significant decrease in particle size, a significant increase in the specific surface area and shorter dissolving time when used for injection. The characteristic particle size was between 200-400 nm. The specific surface area increased from 2.95 to 10.87 m2/g after micronization. When the amount of L-arginin decreased from 0.25 to 0.18 g, the mixture of nanosized cephradine and L-arginine could still dissolve in 1 min. The X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) analysis indicated that the physical characteristics and molecular states remained unchanged after the recrystallization process. This method had potential application in industrial fields because of its low cost, efficient processing and the ease of scaling-up.

  17. Luminescence properties of YAG:Nd nano-sized ceramic powders ...

    Indian Academy of Sciences (India)

    equipment and crucible material and fabricating large sizes and high neodymium concentrations are difficult. Recent investigations have indicated that YAG:Nd3+ polycrystalline nano-sized ceramic powders are among the most promis- ing materials for solid-state lasers (Skita et al 1991; Ikesue et al 1995; Lu et al 2000a, b, ...

  18. Luminescence properties of YAG:Nd nano-sized ceramic powders ...

    Indian Academy of Sciences (India)

    Nano-sized ceramic powders with weaker aggregation of Nd3+-doped yttrium aluminum garnet. (YAG:Nd3+) ... Under excitation at 488 nm, YAG:Nd3+ nano- ..... Rabinovitch Y, Bogicevic C, Karolak F, Tétard D and Dammak H. 2008 J. Mater. Process Tech. 199 314. Sekino T and Sogabe Y 1993 Rev. Laser Eng. 21 827.

  19. Characterization of nano-size heterogeneities by small-angle-scattering

    International Nuclear Information System (INIS)

    Ohnuma, Masato

    2012-01-01

    Techniques of Small-Angle Neutron and X-ray Scattering (SANS and SAXS) are overviewed from principle to applications. Importance of characterizing composition of nano-size heterogeneity is explained based on the results obtained by combination of SANS and SAXS. (author)

  20. Adsorption study of Pb 2 ions on nanosized SnO2, synthesized by ...

    Indian Academy of Sciences (India)

    Adsorption of Pb2+ ions on combustion derived nanosized SnO2 is studied. The as synthesized SnO2 and lead ions adsorbed SnO2 are characterized by X-ray diffraction (XRD), scanning electron micrograph (SEM), and infrared spectroscopic (IR) techniques. The eluent is characterized by atomic absorption spectroscopy ...

  1. Solvent-free synthesis of nanosized hierarchical sodalite zeolite with a multi-hollow polycrystalline structure

    KAUST Repository

    Zeng, Shangjing

    2016-08-03

    A solvent-free route is developed for preparing nanoscale sodalite zeolite with a multi-hollow structure. Furthermore, the synthesis of nanosized hollow sodalite polycrystalline aggregates with a mesoporous structure and high crystallinity is investigated by adding an organosilane surfactant as a mesopore-generating agent.

  2. Nano-sized aerosol classification, collection and analysis--method development using dental composite materials.

    Science.gov (United States)

    Bogdan, Axel; Buckett, Mary I; Japuntich, Daniel A

    2014-01-01

    This article presents a methodical approach for generating, collecting, and analyzing nano-size (1-100 nm) aerosol from abraded dental composite materials. Existing aerosol sampling instruments were combined with a custom-made sampling chamber to create and sample a fresh, steady-state aerosol size distribution before significant Brownian coagulation. Morphological, size, and compositional information was obtained by Transmission Electron Microscopy (TEM). To create samples sizes suitable for TEM analysis, aerosol concentrations in the test chamber had to be much higher than one would typically expect in a dental office, and therefore, these results do not represent patient or dental personnel exposures. Results show that nano-size aerosol was produced by the dental drill alone, with and without cooling water drip, prior to abrasion of dental composite. During abrasion, aerosol generation seemed independent of the percent filler load of the restorative material and the operator who generated the test aerosol. TEM investigation showed that "chunks" of filler and resin were generated in the nano-size range; however, free nano-size filler particles were not observed. The majority of observed particles consisted of oil droplets, ash, and graphitic structures.

  3. Synthesis and characterization of nano-sized CaCO3 in purified diet

    Science.gov (United States)

    Mulyaningsih, N. N.; Tresnasari, D. R.; Ramahwati, M. R.; Juwono, A. L.; Soejoko, D. S.; Astuti, D. A.

    2017-07-01

    The growth and development of animals depend strongly on the balanced nutrition in the diet. This research aims is to characterize the weight variations of nano-sized calcium carbonate (CaCO3) in purified diet that to be fed to animal model of rat. The nano-sized CaCO3 was prepared by milling the calcium carbonate particles for 20 hours at a rotation speed of 1000 rpm and resulting particle size in a range of 2-50 nm. Nano-sized CaCO3 added to purified diet to the four formulas that were identified as normal diet (N), deficiency calcium (DC), rich in calcium (RC), and poor calcium (PC) with containing in nano-sized CaCO3 much as 0.50 %, 0.00 %, 0.75 % and 0.25 % respectively. The nutritional content of the purified diet was proximate analyzed, it resulted as followed moisture, ash, fat, protein, crude fiber. The quantities of chemical element were analyzed by atomic absorption spectrometry (AAS), it resulted iron, magnesium, potassium and calcium. The results showed that N diet (Ca: 16,914.29 ppm) were suggested for healthy rats and RC diet (Ca: 33,696.13 ppm) for conditioned osteoporosis rats. The crystalline phases of the samples that were examined by X-ray diffraction showed that crystalline phase increased with the increasing concentration of CaCO3.

  4. Nanosized aerosols from consumer sprays: experimental analysis and exposure modeling for four commercial products

    Science.gov (United States)

    Lorenz, Christiane; Hagendorfer, Harald; von Goetz, Natalie; Kaegi, Ralf; Gehrig, Robert; Ulrich, Andrea; Scheringer, Martin; Hungerbühler, Konrad

    2011-08-01

    Consumer spray products are already on the market in the cosmetics and household sector, which suggest by their label that they contain engineered nanoparticles (ENP). Sprays are considered critical for human health, because the lungs represent a major route for the uptake of ENP into the human body. To contribute to the exposure assessment of ENP in consumer spray products, we analyzed ENP in four commercially available sprays: one antiperspirant, two shoe impregnation sprays, and one plant-strengthening agent. The spray dispersions were analyzed by inductively coupled plasma mass spectrometry (ICPMS) and (scanning-) transmission electron microscopy ((S)TEM). Aerosols were generated by using the original vessels, and analyzed by scanning mobility particle sizer (SMPS) and (S)TEM. On the basis of SMPS results, the nanosized aerosol depositing in the respiratory tract was modeled for female and male consumers. The derived exposure levels reflect a single spray application. We identified ENP in the dispersions of two products (shoe impregnation and plant spray). Nanosized aerosols were observed in three products that contained propellant gas. The aerosol number concentration increased linearly with the sprayed amount, with the highest concentration resulting from the antiperspirant. Modeled aerosol exposure levels were in the range of 1010 nanosized aerosol components per person and application event for the antiperspirant and the impregnation sprays, with the largest fraction of nanosized aerosol depositing in the alveolar region. Negligible exposure from the application of the plant spray (pump spray) was observed.

  5. Primary particles and their agglomerate formation as modifying risk factors of nonfibrous nanosized dust.

    Science.gov (United States)

    Schneider, J; Walter, D; Brückel, B; Rödelsperger, K

    2013-01-01

    The incidence of certain cancers correlates with the number of dust particles in the air. Nanosized particles differ from coarser particles by their increasing tendency to form agglomerates. The dissociation of biodurable agglomerates after deposition in the alveolar region resulted in a higher toxic potential. Biodurable dusts in the urban and workplace environment were analyzed to determine an effect-relevant exposure parameter. The characterization of the dusts relating to their number of primary particles (P(p)) and agglomerates and aggregates (A + A) was performed by electron microscopy. Diesel soot, toner material, and seven further dust samples in the workplace environment are composed of high numbers of nanosized primary particles (agglomerates. Primary particles of rock, kaoline, and seven further dusts sampled in the workplace are not nanosized. In a multivariate analysis that predicted lung tumor risk, the mass, volume, and numbers of A + A and P(p) per milligram dust were shown to be relevant parameters. Dose-response relationships revealed an increased tumor risk in rats with higher numbers of P(p) in nanosized dust, which occurs unintentionally in the environment.

  6. Elaboration and Characterization of Nano-Sized AlxMoyOz/Al Thermites

    National Research Council Canada - National Science Library

    Comet, M; Spitzer, D

    2006-01-01

    ...) has been developed at the Institut franco-allemand de recherches de Saint Louis (ISL). This process consists of a new sol-gel method nano-sized mixed AlxMoyOz phases whose structure is correlated to the chemical composition...

  7. Enhanced dissolution of nanosize CuO in the presence of meso- and micro-pores

    International Nuclear Information System (INIS)

    Huang, C.-H.; Wang, H. Paul; Huang, H.-L.; Hsiung, T.-L.; Tang, F.-C.

    2007-01-01

    Dissolution of nanosize CuO in the chemical mechanical planarization (CMP) waste water in the presence of micropores (0.74 nm) of Y and mesopores (4 nm) of MCM-41 has been studied by X-ray absorption near edge structure (XANES) spectroscopy in the present work. Since pore openings of Y and MCM-41 are much less than the size of nano-CuO (about 13 nm) in the CMP waste water, CuO is not able to be incorporated directly into the pore systems. At least two reaction paths might be involved in the incorporation process: (1) dissolution of CuO and (2) incorporation of Cu 2+ into Y and MCM-41. Experimentally, during the incorporation process, Y might possess equivalent electric fields of 20-50 V/cm for dissolution of nanosize CuO. Interestingly we found that dissolution of nanosize CuO in the CMP waste water was enhanced, for instance, about 65% and 87% of nanosize CuO were incorporated (as Cu 2+ ) and incorporated into Y and MCM-41, respectively

  8. Application of the ellipsoid modeling of the average shape of nanosized crystallites in powder diffraction

    DEFF Research Database (Denmark)

    Katerinopoulou, Anna; Balic Zunic, Tonci; Lundegaard, Lars Fahl

    2012-01-01

    Anisotropic broadening correction in X-ray powder diffraction by an ellipsoidal formula is applied on samples with nanosized crystals. Two cases of minerals with largely anisotropic crystallite shapes are presented. The properly applied formalism not only improves the fitting of the theoretical...

  9. Design and Performance of Rigid Nanosize Multimetallic Cartwheel Pincer Compounds as Lewis-Acid Catalysts

    NARCIS (Netherlands)

    Koten, G. van; Dijkstra, H.P.; Meijer, M.D.; Patel, J.; Kreiter, R.; Klink, G.P.M. van; Lutz, M.H.; Spek, A.L.; Canty, A.J.

    2001-01-01

    Novel strategies for the preparation of rigid cartwheel pincer metal complexes have been developed. The aromatic backbone of these materials ensures a high rigidity, which is expected to be important for a high retention when these multimetallic nanosize complexes are applied as homogeneous

  10. Formulation of solid nano-sized particles in a gel-forming system

    DEFF Research Database (Denmark)

    2013-01-01

    The present invention relates to novel formulations comprising a plurality of nano-sized solid particles and a gel-forming system, useful e.g. for imaging of the body of a mammal. Also described are kits comprising such formulations and imaging methods utilizing such formulations or kits....

  11. Enthalpy Effect of Adding Cobalt to Liquid Sn-3.8Ag-0.7Cu Lead-Free Solder Alloy: Difference between Bulk and Nanosized Cobalt.

    Science.gov (United States)

    Yakymovych, Andriy; Kaptay, George; Roshanghias, Ali; Flandorfer, Hans; Ipser, Herbert

    2016-01-28

    Heat effects for the addition of Co in bulk and nanosized forms into the liquid Sn-3.8Ag-0.7Cu alloy were studied using drop calorimetry at four temperatures between 673 and 1173 K. Significant differences in the heat effects between nano and bulk Co additions were observed. The considerably more exothermic values of the measured enthalpy for nano Co additions are connected with the loss of the surface enthalpy of the nanoparticles due to the elimination of the surface of the nanoparticles upon their dissolution in the liquid alloy. This effect is shown to be independent of the calorimeter temperature (it depends only on the dropping temperature through the temperature dependence of the surface energy of the nanoparticles). Integral and partial enthalpies of mixing for Co in the liquid SAC-alloy were evaluated from the experimental data.

  12. Grain Refinement and Mechanical Properties of Cu-Cr-Zr Alloys with Different Nano-Sized TiCp Addition.

    Science.gov (United States)

    Zhang, Dongdong; Bai, Fang; Wang, Yong; Wang, Jinguo; Wang, Wenquan

    2017-08-08

    The TiC p /Cu master alloy was prepared via thermal explosion reaction. Afterwards, the nano-sized TiC p /Cu master alloy was dispersed by electromagnetic stirring casting into the melting Cu-Cr-Zr alloys to fabricate the nano-sized TiC p -reinforced Cu-Cr-Zr composites. Results show that nano-sized TiC p can effectively refine the grain size of Cu-Cr-Zr alloys. The morphologies of grain in Cu-Cr-Zr composites changed from dendritic grain to equiaxed crystal because of the addition and dispersion of nano-sized TiC p . The grain size decreased from 82 to 28 μm with the nano-sized TiC p content. Compared with Cu-Cr-Zr alloys, the ultimate compressive strength (σ UCS ) and yield strength (σ 0.2 ) of 4 wt% TiC p -reinforced Cu-Cr-Zr composites increased by 6.7% and 9.4%, respectively. The wear resistance of the nano-sized TiCp-reinforced Cu-Cr-Zr composites increased with the increasing nano-sized TiCp content. The wear loss of the nano-sized TiC p -reinforced Cu-Cr-Zr composites decreased with the increasing TiC p content under abrasive particles. The eletrical conductivity of Cu-Cr-Zr alloys, 2% and 4% nano-sized TiCp-reinforced Cu-Cr-Zr composites are 64.71% IACS, 56.77% IACS and 52.93% IACS, respectively.

  13. Electrical properties of nanosized non-barrier inhomogeneities in Zn-based metal-semiconductor contacts to InP

    DEFF Research Database (Denmark)

    Clausen, Thomas; Leistiko, Otto

    1998-01-01

    We have found that the electrical properties of carriers across the metal-semiconductor interface for alloyed Zn based metallizations to n- and p-InP are dominated by nanosized non-barrier inhomogeneities. The effective area covered by the nanosized regions is a small fraction of the contact area...... resulting in high values of the specific contact resistance to p-InP. For n(-)-InP, thermionic emission across nanosized inhomogeneities dominates the carrier flow when T-ann > 440 degrees C. (C) 1998 Elsevier Science B.V....

  14. Highly sensitive and selective electrochemical detection of sub-ppb level chromium(VI) using nano-sized gold particle.

    Science.gov (United States)

    Jena, Bikash Kumar; Raj, C Retna

    2008-06-30

    Gold nanoparticle based nanostructured electrode has been developed for the amperometric detection of ultratrace amount of toxic Cr(VI). The nano-sized Au particles have been grown on a conducting substrate modified with sol-gel-derived thiol functionalized silicate network and used for the electroanalysis of Cr(VI). The nanostructured interface show well-defined voltammetric peak for the reduction of Cr(VI) at approximately 0.4 V. The voltammetric behavior of Cr(VI) strongly depends on the coverage of nanoparticle on the electrode surface. Constant potential amperometry has been used for the detection of Cr(VI) at well below the guideline value set by World Health Organization (WHO). This electrode is highly sensitive (30+/-0.2 nA/ppb) and the detection limit (S/N=9) was 0.1 ppb. Cr(III) and coexisting other metal ions and surface active agent present in water do not interfere with the amperometric measurement of Cr(VI). This nanostructured electrode is highly stable and it can be used for continuous measurement of Cr(VI) without using any pretreatment or activation procedures. The accuracy of the measurement has been validated by measuring the concentration of Cr(VI) in the certified reference material (CRM).

  15. Robust topology design of periodic grating surfaces

    DEFF Research Database (Denmark)

    Friis, Kasper Storgaard; Sigmund, Ole

    2012-01-01

    Modern nanoscale manufacturing techniques allow for a high degree of flexibility in designing surface microstructures and nanostructures. Injection molding of nanosized features allows for mass production of plastic components with a tailored nanostructure producing specific optical effects...... depending on the purpose. This work details the use of topology optimization for designing periodic polymer grating surfaces with complex optical properties. A method based on robust topology optimization is formulated for designing the nanostructure of plastic surfaces with extreme reflection...

  16. Constant pressure-controlled extrusion method for the preparation of Nano-sized lipid vesicles.

    Science.gov (United States)

    Morton, Leslie A; Saludes, Jonel P; Yin, Hang

    2012-06-22

    Liposomes are artificially prepared vesicles consisting of natural and synthetic phospholipids that are widely used as a cell membrane mimicking platform to study protein-protein and protein-lipid interactions, monitor drug delivery, and encapsulation. Phospholipids naturally create curved lipid bilayers, distinguishing itself from a micelle. Liposomes are traditionally classified by size and number of bilayers, i.e. large unilamellar vesicles (LUVs), small unilamellar vesicles (SUVs) and multilamellar vesicles (MLVs). In particular, the preparation of homogeneous liposomes of various sizes is important for studying membrane curvature that plays a vital role in cell signaling, endo- and exocytosis, membrane fusion, and protein trafficking. Several groups analyze how proteins are used to modulate processes that involve membrane curvature and thus prepare liposomes of diameters liposome-drug encapsulation, studying liposomes as vehicles to carry and deliver a drug of interest. Drug encapsulation can be achieved as reported during liposome formation. Our extrusion step should not affect the encapsulated drug for two reasons, i.e. (1) drug encapsulation should be achieved prior to this step and liposomes should retain their natural biophysical stability, securely carrying the drug in the aqueous core. These research goals further suggest the need for an optimized method to design stable sub-micron lipid vesicles. Nonetheless, the current liposome preparation technologies (sonication, freeze-and-thaw, sedimentation) do not allow preparation of liposomes with highly curved surface (i.e. diameter liposomes. Manual extrusion using gas-tight syringes and polycarbonate membranes, is a common practice but heterogeneity is often observed when using pore sizes liposomes whose diameters range between 30 and 400 nm. Dynamic light scattering (DLS), electron microscopy and nanoparticle tracking analysis (NTA) were used to quantify the liposome sizes as described in our protocol

  17. Synthesis of Nano-sized Boehmites for Optimum Phosphate Sorption

    DEFF Research Database (Denmark)

    Watanabe, Yujiro; Kasama, Takeshi; Fukushi, Keisuke

    2011-01-01

    the highest amount of phosphate sorption (1.73 mmol g-1 at pH 3.3) compared with Al-bearing materials. The reaction mechanism during phosphate sorption was described by the anion exchange reaction between phosphate ions in sodium phosphate solution and hydroxide ions on boehmite surfaces. Therefore...

  18. Novel detection system for biomolecules using nano-sized bacterial magnetic particles and magnetic force microscopy.

    Science.gov (United States)

    Amemiya, Yosuke; Tanaka, Tsuyoshi; Yoza, Brandon; Matsunaga, Tadashi

    2005-11-21

    A system for streptavidin detection using biotin conjugated to nano-sized bacterial magnetic particles (BMPs) has been developed. BMPs, isolated from magnetic bacteria, were used as magnetic markers for magnetic force microscopy (MFM) imaging. The magnetic signal was obtained from a single particle using MFM without application of an external magnetic field. The number of biotin conjugated BMPs (biotin-BMPs) bound to streptavidin immobilized on the glass slides increased with streptavidin concentrations up to 100 pg/ml. The minimum streptavidin detection limit using this technique is 1 pg/ml, which is 100 times more sensitive than a conventional fluorescent detection system. This is the first report using single domain nano-sized magnetic particles as magnetic markers for biosensing. This assay system can be used for immunoassay and DNA detection with high sensitivities.

  19. Synthesis of nano-sized zirconium carbide by a sol-gel route

    Energy Technology Data Exchange (ETDEWEB)

    Dolle, M.; Gosset, D.; Simeone, D. [CEA Saclay, DMN, SRMA, Lab Anal Microstruct Mat, F-91191 Gif Sur Yvette (France); Bogicevic, C.; Karolak, F.; Baldinozzi, G. [Ecole Cent Paris, CNRS, UMR 8580, Lab Struct Proprietes and Modelisat Solides, F-92295 Chatenay Malabry (France)

    2007-07-01

    Nano-sized zirconium carbide was synthesized by a new simple sol-gel method Using zirconium n-prop-oxide, acetic acid as chemical modifier, and saccharose as carbon source. When heat-treated at 900 C under flowing argon, gels transformed into intimately mixed amorphous carbon and nano-sized tetragonal ZrO{sub 2}. Further heat treatments above 1200 degrees C led to the formation of zirconium carbide with some dissolved oxygen in the lattice. Oxygen content Could be reduced by increasing the heat treatment temperature from 1400 to 1600 degrees C, which unfortunately also induced a mean crystallites size increase from 90 to 150 inn. Short heat treatments above 1600 degrees C were carried out to further purify the samples and to limit the particles growth. A compromise between purity and average crystallite's size could then be found. Powders were assessed using X-ray diffraction, thermal analysis and scanning electron microscopy. (authors)

  20. NANO-SIZED PIGMENT APPLICATIONS IN İZNİK TILES

    Directory of Open Access Journals (Sweden)

    Esin GÜNAY

    2012-12-01

    Full Text Available Traditional İznik tiles are known as “unproducable” due to its high quartz content. İznik tiles contain four different layers as “body, engobe (slip, decors and glaze” and each one has some different starting materials. Recent studies have showed that the production techniques and the particle size of pigments are important parameters in development of colours. TUBITAK MRC and İznik Foundation carried out an experimental work to improve and understand the effects of nanotechnology application to İznik tiles. High quartz content was kept as it is and pigments were applied in decorationas nano-sized pigments.İznik tiles were produced and comparison was carried out between traditional and modern İznik tiles in colour and brightness. Characterization techniques were used in order to understand andcompare the results and also the effects of nano-sized pigments to İznik tiles.

  1. Study on the Influence of Nano-SiC on the Structure and Properties of Nodular Cast Iron

    Science.gov (United States)

    Zhu, Ruixiang; SU, Yong; Qin, Xinyu

    2017-10-01

    In this paper, the effect of adding Nano-SiC on the structure and mechanical properties of nodular cast iron during inoculation and spheroidizing process is mainly studied. Three sets of samples were set up: one group is without adding Nano-SiC, and the other two groups are adding Nano-SiC in the spheroidizing process and inoculation step. The three groups of castings were sampled from the core and 1/4 respectively and treated by isothermal quenching. The influences of Nano-SiC and heat treatment process on the microstructure and mechanical properties of nodular cast iron were discussed through the observation of impact work, hardness and metallographic structure of Vivtorinox. The experimental results show that with the addition of Nano-SiC, the spheroidization rate, spheroidization degree and graphitization of the graphite in casting structure are improved. In mechanical properties, the impact toughness of the samples with adding Nano-SiC during inoculation is the best, and the hardness of nodular cast iron can be improved. After heat treatment, the impact toughness of nodular cast iron samples increased obviously, but the hardness decreased generally.

  2. Nanosized rods agglomerates as a new approach for formulation of a dry powder inhaler

    OpenAIRE

    Salem, HF; Abdelrahim, ME; Eid, K Abo; Sharaf, MA

    2011-01-01

    HF Salem1 ME Abdelrahim2 K Abo Eid3 MA Sharaf3,41Department of Pharmaceutics, 2Department of Clinical Pharmacy, Faculty of Pharmacy, The University of Beni Suef, Beni Suef; 3Department of Chemistry, Helwan University, Ain Helwan, Helwan, Egypt; 4Department of Chemistry, The American University in Cairo, New Cairo, Helwan 11835, EgyptBackground: Nanosized dry powder inhalers provide higher stability for poorly water-soluble drugs as compared with liquid formulations. However, the respirable pa...

  3. Synthesis and characterization of nanosized Cu/ZnO catalyst by polyol method.

    Science.gov (United States)

    Altinçekiç, Tuba Gürkaynak; Boz, Ismail; Aktürk, Selçuk

    2008-02-01

    Nanosized catalysts composed of metallic copper supported on zinc oxide have been synthesized by the polyol process. Average crystallite size of copper was between 10 and 45 nm. Cu/ZnO catalyst particles were characterized by various techniques, such as X-ray Powder Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Selected Area Electron Diffraction (SAED), and dynamic light scattering analysis (DLS).

  4. Low temperature synthesis of nanosized Mn1–xZnxFe2O4 ferrites ...

    Indian Academy of Sciences (India)

    Nanosized Mn1–ZnFe2O4 ( = 0, 0.1, 0.3, 0.5, 0.6, 0.7, 0.9) mixed ferrite samples of particle size < 12 nm were prepared using the co-precipitation technique by doping the Zn2+ ion impurities. Autoclave was employed to maintain constant temperature of 80°C and a constant pressure. The X-ray analysis and the IR ...

  5. Binary mixing of micelles using Pluronics for a nano-sized drug delivery system.

    Science.gov (United States)

    Lee, Eun Seong; Oh, Young Taik; Youn, Yu Seok; Nam, Myounghwa; Park, Byungtae; Yun, Jungmin; Kim, Ji Hoon; Song, Ho-Taek; Oh, Kyung Taek

    2011-01-01

    Pluronics with different structural compositions and properties are used for several applications, including drug delivery systems. We developed a binary mixing system with two Pluronics, L121/P123, as a nano-sized drug delivery carrier. The lamellar-forming Pluronic L121 (0.1 wt%) was incorporated with Pluronic P123 to produce nano-sized dispersions (in case of 0.1 and 0.5 wt% P123) with high stability due to Pluronic P123 and high solubilization capacity due to Pluronic L121. The binary systems were spherical and less than 200-nm diameter, with high thermodynamic stability (at least 2 weeks) in aqueous solution. The CMC of the binary system was located in the middle of the CMC of each polymer. In particular, the solubilization capacity of the binary system (0.1/0.1 wt%) was higher than mono-systems of P123. The main advantage of binary systems is overcoming limitations of mono systems to allow tailored mixing of block copolymers with different physicochemical characteristics. These nano-sized systems may have potential as anticancer drug delivery systems with simple preparation method, high stability, and high loading capacity. Copyright © 2010 Elsevier B.V. All rights reserved.

  6. An agar diffusion study comparing the antimicrobial activity of Nanoseal with some other endodontic sealers.

    Science.gov (United States)

    Aal-Saraj, Ali Burak; Ariffin, Zaihan; Masudi, Sam'an Malik

    2012-08-01

    The aim of this study was to evaluate the antimicrobial activity of a new experimental nano-hydroxyapatite epoxy resin-based sealer (Nanoseal) with several other commercially available sealers; AH26, Tubliseal, Sealapex and Roekoseal against Enterococcus faecalis, Pseudomonas aeruginosa, Streptococcus mutans, Streptococcus sobrinus and Escherichia coli for up to 7 days. Agar diffusion was used in this study. Fifty Muller-Hinton agar plates were prepared and divided into five experimental groups (n = 10), for each micro-organism. Another 10 agar plates were used as positive and negative controls. Endodontic sealers were tested against each micro-organism. Inhibition zones produced were recorded. The results of this study showed that all test materials exhibited inhibition zones towards the tested micro-organisms for 7 days except for Roekoseal, which showed no inhibition zones. Nanoseal and AH26 exhibited similar zones of inhibition. Significant difference was found between Nanoseal and the other tested sealers (P < 0.001). © 2010 The Authors. Australian Endodontic Journal © 2010 Australian Society of Endodontology.

  7. Nano-Sized Fume Biogas Production from Food Waster Using Semi-Continuous Anaerobic Digester.

    Science.gov (United States)

    Park, Keum-Joo; Seo, Seong-Gyu; Kim, Eun-Sik; Islam, M N; Song, Hyung-Woon; Yoon, Hyung-Sun

    2018-02-01

    In this study, the nano-sized fume biogas production from food waste was investigated using lab scale semi-continuous stirred tank reactor (SCSTR) at 35 °C with 30d HRT and 30L working volume. The mesophilic digestion test was performed with three different feed materials (food waste) and food to microorganism (F/M) ratios (0.13, 0.34, and 0.27) in the same experiment. The results showed that the F/M ratios significantly affected the biogas production rate. The highest production rate was obtained at F/M ratio of 0.13. Nano-sized fume biogas produced in anaerobic digestion consists of 68.7% CH4, 31.2% CO2 and 30~200 nm particle. The average nano-sized fume biogas and methane production of digester were 29.96 L/Kg versus day-1 and 20.58 L/Kg versus day-1, respectively. The CH4 could be calculated as the heat energy 1.85 Kcal/Kg VS day-1. The digestion was operated without addition of chemicals or nutrients into the system.

  8. Nanosized hydroxyapatite and other calcium phosphates: chemistry of formation and application as drug and gene delivery agents.

    Science.gov (United States)

    Uskoković, Vuk; Uskoković, Dragan P

    2011-01-01

    The first part of this review looks at the fundamental properties of hydroxyapatite (HAP), the basic mineral constituent of mammalian hard tissues, including the physicochemical features that govern its formation by precipitation. A special emphasis is placed on the analysis of qualities of different methods of synthesis and of the phase transformations intrinsic to the formation of HAP following precipitation from aqueous solutions. This serves as an introduction to the second part and the main subject of this review, which relates to the discourse regarding the prospects of fabrication of ultrafine, nanosized particles based on calcium phosphate carriers with various therapeutic and/or diagnostic agents coated on and/or encapsulated within the particles. It is said that the particles could be either surface-functionalized with amphiphiles, peptides, proteins, or nucleic acids or injected with therapeutic agents, magnetic ions, or fluorescent molecules. Depending on the additive, they could be subsequently used for a variety of applications, including the controlled delivery and release of therapeutic agents (extracellularly or intracellularly), magnetic resonance imaging and hyperthermia therapy, cell separation, blood detoxification, peptide or oligonucleotide chromatography and ultrasensitive detection of biomolecules, and in vivo and in vitro gene transfection. Calcium phosphate nanoparticles as carriers of therapeutic agents that would enable a controlled drug release to treat a given bone infection and at the same be resorbed in the body so as to regenerate hard tissue lost to disease are emphasized hereby as one of the potentially attractive smart materials for the modern medicine. © 2010 Wiley Periodicals, Inc.

  9. Nano-Sized Cuboid-Shaped Phase in Mg-Nd-Y Alloy and its Behavior During Isothermal Aging.

    Science.gov (United States)

    Zheng, Jingxu; Luo, Zhongyuan; Tan, Lida; Chen, Bin

    2016-12-01

    In the present study, nano-sized cuboid-shaped particles in Mg-Nd-Y are studied by means of Cs-corrected atomic-scale high-angle annular dark-field scanning transmission electron microscopy. The structure of the cuboid-shaped phase is identified to be yttrium (major component) and neodymium atoms in face-centered cubic arrangement without the participation of Mg. The lattice parameter a=5.15 Å. During isothermal aging at 225°C, Mg3(Nd,Y) precipitates adhere to surface (100) planes of the cuboid-shaped particles with the orientation relationship: $[100]_{{{\\rm Mg}_{{\\rm 3}} {\\rm RE}}} \\,/\\,\\,/\\,[100]_{{{\\rm Cuboid}}} $ and $[310]_{{{\\rm Mg}_{{\\rm 3}} {\\rm RE}}} \\,/\\,\\,/\\,[012]_{{{\\rm Cuboid}}} $ . The fully coherent interfaces between the precipitates and the cuboid-shaped phases are reconstructed and categorized into two types: $(400)_{{{\\rm Mg}_{{\\rm 3}} {\\rm RE}}} $ interface and $(200)_{{{\\rm Mg}_{{\\rm 3}} {\\rm RE}}} $ interface.

  10. Probing Membrane Viscosity and Interleaflet Friction of Supported Lipid Bilayers by Tracking Electrostatically Adsorbed, Nano-Sized Vesicles.

    Science.gov (United States)

    Tabaei, Seyed R; Gillissen, Jurriaan J J; Cho, Nam-Joon

    2016-12-01

    Particle tracking is used to measure the diffusional motion of nanosized (≈100 nm), lipid vesicles that are electrostatically adsorbed onto a solid supported lipid bilayer. It is found that the motion of membrane-adhering vesicles is Brownian and depends inversely on the vesicle size, but is insensitive to the vesicle surface charge. The measured diffusivity agrees well with the Evans-Sackmann model for the diffusion of inclusions in supported, fluidic membranes. The agreement implies that the vesicle motion is coupled to that of a nanoscopic lipid cluster in the upper leaflet, which slides over the lower leaflet. The diffusivity of membrane-adhering vesicles is therefore predominantly governed by the interleaflet friction coefficient, while the diffusivity of single lipids is mainly governed by the membrane viscosity. Combined with fluorescence recovery after photobleaching analysis, the interleaflet friction coefficient and the membrane viscosity are determined by applying the Evans-Sackmann model to the measured diffusivity of membrane adhering vesicles and that of supported membrane lipids. This approach provides an alternative to existing methods for measuring the interleaflet friction coefficient and the membrane viscosity. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Synthesis of Polyhydroxybutyrate Particles with Micro-to-Nanosized Structures and Application as Protective Coating for Packaging Papers.

    Science.gov (United States)

    Rastogi, Vibhore Kumar; Samyn, Pieter

    2016-12-30

    This study reports on the development of bio-based hydrophobic coatings for packaging papers through deposition of polyhydroxybutyrate (PHB) particles in combination with nanofibrillated cellulose (NFC) and plant wax. In the first approach, PHB particles in the micrometer range (PHB-MP) were prepared through a phase-separation technique providing internally-nanosized structures. The particles were transferred as a coating by dip-coating filter papers in the particle suspension, followed by sizing with a carnauba wax solution. This approach allowed partial to almost full surface coverage of PHB-MP over the paper surface, resulting in static water contact angles of 105°-122° and 129°-144° after additional wax coating. In the second approach, PHB particles with submicron sizes (PHB-SP) were synthesized by an oil-in-water emulsion (o/w) solvent evaporation method and mixed in aqueous suspensions with 0-7 wt % NFC. After dip-coating filter papers in PHB-SP/NFC suspensions and sizing with a carnauba wax solution, static water contact angles of 112°-152° were obtained. The intrinsic properties of the particles were analyzed by scanning electron microscopy, thermal analysis and infrared spectroscopy, indicating higher crystallinity for PHB-SP than PHB-MP. The chemical interactions between the more amorphous PHB-MP particles and paper fibers were identified as an esterification reaction, while the morphology of the NFC fibrillar network was playing a key role as the binding agent in the retention of more crystalline PHB-SP at the paper surface, hence contributing to higher hydrophobicity.

  12. Synthesis of Polyhydroxybutyrate Particles with Micro-to-Nanosized Structures and Application as Protective Coating for Packaging Papers

    Directory of Open Access Journals (Sweden)

    Vibhore Kumar Rastogi

    2016-12-01

    Full Text Available This study reports on the development of bio-based hydrophobic coatings for packaging papers through deposition of polyhydroxybutyrate (PHB particles in combination with nanofibrillated cellulose (NFC and plant wax. In the first approach, PHB particles in the micrometer range (PHB-MP were prepared through a phase-separation technique providing internally-nanosized structures. The particles were transferred as a coating by dip-coating filter papers in the particle suspension, followed by sizing with a carnauba wax solution. This approach allowed partial to almost full surface coverage of PHB-MP over the paper surface, resulting in static water contact angles of 105°–122° and 129°–144° after additional wax coating. In the second approach, PHB particles with submicron sizes (PHB-SP were synthesized by an oil-in-water emulsion (o/w solvent evaporation method and mixed in aqueous suspensions with 0–7 wt % NFC. After dip-coating filter papers in PHB-SP/NFC suspensions and sizing with a carnauba wax solution, static water contact angles of 112°–152° were obtained. The intrinsic properties of the particles were analyzed by scanning electron microscopy, thermal analysis and infrared spectroscopy, indicating higher crystallinity for PHB-SP than PHB-MP. The chemical interactions between the more amorphous PHB-MP particles and paper fibers were identified as an esterification reaction, while the morphology of the NFC fibrillar network was playing a key role as the binding agent in the retention of more crystalline PHB-SP at the paper surface, hence contributing to higher hydrophobicity.

  13. Synthesis of Polyhydroxybutyrate Particles with Micro-to-Nanosized Structures and Application as Protective Coating for Packaging Papers

    Science.gov (United States)

    Rastogi, Vibhore Kumar; Samyn, Pieter

    2016-01-01

    This study reports on the development of bio-based hydrophobic coatings for packaging papers through deposition of polyhydroxybutyrate (PHB) particles in combination with nanofibrillated cellulose (NFC) and plant wax. In the first approach, PHB particles in the micrometer range (PHB-MP) were prepared through a phase-separation technique providing internally-nanosized structures. The particles were transferred as a coating by dip-coating filter papers in the particle suspension, followed by sizing with a carnauba wax solution. This approach allowed partial to almost full surface coverage of PHB-MP over the paper surface, resulting in static water contact angles of 105°–122° and 129°–144° after additional wax coating. In the second approach, PHB particles with submicron sizes (PHB-SP) were synthesized by an oil-in-water emulsion (o/w) solvent evaporation method and mixed in aqueous suspensions with 0–7 wt % NFC. After dip-coating filter papers in PHB-SP/NFC suspensions and sizing with a carnauba wax solution, static water contact angles of 112°–152° were obtained. The intrinsic properties of the particles were analyzed by scanning electron microscopy, thermal analysis and infrared spectroscopy, indicating higher crystallinity for PHB-SP than PHB-MP. The chemical interactions between the more amorphous PHB-MP particles and paper fibers were identified as an esterification reaction, while the morphology of the NFC fibrillar network was playing a key role as the binding agent in the retention of more crystalline PHB-SP at the paper surface, hence contributing to higher hydrophobicity. PMID:28336839

  14. Spectral-optical-electrical-thermal properties of deposited thin films of nano-sized calcium(II)-8-hydroxy-5,7-dinitroquinolate complex.

    Science.gov (United States)

    Farag, A A M; Haggag, Sawsan M S; Mahmoud, Mohamed E

    2011-11-01

    Spectral-optical-electrical-thermal properties of deposited thin films of nano-sized calcium(II)-8-hydroxy-5,7-dinitroquinolate complex, Ca[((NO(2))(2)-8HQ)(2)], were explored, studied and evaluated in this work. Thin films of Ca[((NO(2))(2)-8HQ)(2)] were assembled by using a direct, simple and efficient layer-by-layer (LBL) chemical deposition technique. The optical properties of thin films were investigated by using spectrophotometric measurements of transmittance and reflectance at normal incidence in the wavelength range 200-2500 nm. The refractive index, n, and the absorption index, k, of Ca[((NO(2))(2)-8HQ)(2)] films were determined from the measured transmittance and reflectance. The real and imaginary dielectric constants were also determined. The analysis of the spectral behavior of the absorption coefficient in the intrinsic absorption region reveals a direct allowed transition with band gaps of 1.1 eV and 2.4 eV for the optical and transport energy gaps, respectively. The current-voltage characteristics of Ca[((NO(2))(2)-8HQ)(2)] showed a trap-charge limited conduction in determining the current at the intermediate and high bias regimes. Graphical representation of the current-voltage characteristics yields three distinct linear parts indicating the existence of three conduction mechanisms. Structural characterization and identification were confirmed by using Fourier transform infrared spectroscopy (FT-IR). Scanning electron microscopy (SEM) was also used to image the surface morphology of the deposited nano-sized metal complex and such study revealed a high homogeneity in surface spherical particle distribution with average particles size in the range 20-40 nm. Thermal gravimetric analysis (TGA) was also studied for [(NO(2))(2)-8HQ] and Ca[((NO(2))(2)-8HQ)(2)] to evaluate and confirm the thermal stability characteristics incorporated into the synthesized nano-sized Ca[((NO(2))(2)-8HQ)(2)] complex. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. Coupling of Nanocrystalline Anatase TiO2 to Porous Nanosized LaFeO3 for Efficient Visible-Light Photocatalytic Degradation of Pollutants

    Directory of Open Access Journals (Sweden)

    Muhammad Humayun

    2016-01-01

    Full Text Available In this work we have successfully fabricated nanocrystalline anatase TiO2/perovskite-type porous nanosized LaFeO3 (T/P-LFO nanocomposites using a simple wet chemical method. It is clearly demonstrated by means of atmosphere-controlled steady-state surface photovoltage spectroscopy (SPS responses, photoluminescence spectra, and fluorescence spectra related to the formed OH− radical amount that the photogenerated charge carriers in the resultant T/P-LFO nanocomposites with a proper mole ratio percentage of TiO2 display much higher separation in comparison to the P-LFO alone. This is highly responsible for the improved visible-light activities of T/P-LFO nanocomposites for photocatalytic degradation of gas-phase acetaldehyde and liquid-phase phenol. This work will provide a feasible route to synthesize visible-light responsive nano-photocatalysts for efficient solar energy utilization.

  16. Nanosized CuO and ZnO Catalyst Supported on Honeycomb-Typed Monolith for Hydrogenation of Carbon Dioxide to Methyl Alcohol.

    Science.gov (United States)

    Park, Chul-Min; Ahn, Won-Ju; Jo, Woong-Kyu; Song, Jin-Hun; Oh, Chang-Yeop; Jeong, Young-Shin; Chung, Min-Chul; Park, Kwon-Pil; Kim, Ki-Joong; Jeong, Woon-Jo; Sohn, Bo-Kyun; Jung, Sang-Chul; Lee, Do-Jin; Ahn, Byeong-Kwon; Ahn, Ho-Geun

    2015-01-01

    The greenhouse effect of carbon dioxide (CO2) has been recognized as one of the most serious problems in the world. Conversion of CO2 to methyl alcohol (CH3OH) was studied using catalytic chemical methods. Honeycomb-typed monolith used as catalyst support was 400 cell/inch2. Pretreatment of the monolith surface was carried out by thermal treatment and acid treatment. Monolith-supported nanosized CuO-ZnO catalysts were prepared by wash-coat method. The prepared catalysts were characterized by using SEM, TEM, and XRD. The catalytic activity for CO2 hydrogenation to CH3OH was investigated using a flow-type reactor with varying reaction temperature, reaction pressure and contact time. Conversion of CO2 was increased with increasing reaction temperature, but selectivity to CH3OH was decreased. Optimum reaction temperature was about 250 degrees C under 20 atm. Because of the reverse water gas shift reaction.

  17. Application of nano-sized TiO2 as an inhibitor of stress corrosion cracking in the steam generator tube materials.

    Science.gov (United States)

    Kim, Kyung Mo; Lee, Eun Hee; Kim, Uh Chul; Choi, Byung Seon

    2010-01-01

    Several chemicals were studied to suppress the damage due to a stress corrosion cracking (SCC) of the steam generator (SG) tubes in nuclear power plants. SCC tests were carried out to investigate the performance of TiO2 on several types of SG tube materials. The SCC tests were conducted by using an m-RUB specimen in a 10% NaOH solution at a temperature of 315 degrees C. The test with the addition of TiO2 showed a decrease in the SCC rate for the SG tubing materials. In order to improve the inhibition property in a crevice of TiO2, a sonochemical technique was applied to reduce the size of the TiO2 particle. From the SCC tests with the RUB specimen, the SG tube materials showed an enhanced cracking resistance with the addition of nano-sized TiO2 and the surface property was also changed.

  18. Nucleation of Magnetization Reversal in Individual Nanosized Particles and Wires

    Science.gov (United States)

    Wernsdorfer, W.

    1997-03-01

    Low temperatures magnetization measurements of individual ferromagnetic particles and wires are presented. The detector was a Nb micro-bridge-DC-SQUID, elaborated using electron-beam lithography. We studied particles fabricated by electron beam lithography. They had an elliptic contour with axes between 50 and 1000 nm and a thickness between 5 and 50 nm and were made of Ni, Co, Fe (W. Wernsdorfer et al., J. Magn. Magn. Mat., 145, 33 (1995) and 151, 38 (1995), and Phys. Rev. B, 53, 3341 (1996).). Furthermore, we studied Ni and Co wires (cylinders) with diameters ranging from 40 nm to 100 nm and lengths up to 5000 nm (W. Wernsdorfer et al., Phys. Rev. Lett., 77, 1873 (1996)). They were produced by the technique of electrodeposition in nanoporous polycarbonate membranes (J. Meier, B. Doudin and J.-Ph. Ansermet, J. Appl. Phys, 79, 6010 (1996).). We studied nanoparticles and filled carbon nanotubes synthesized by arc-discharge, with dimensions between 10 and 500 nm. These particles are single crystalline and the surface roughness is about two atomic layers (C. Guerret-Pi=E9court, Y. Le Bouar, A. Loiseau and H. Pascard, Nature, 372, 761 (1994).). Finally, we studied single crystalline particles elaborated by colloidal self assemblies (M. P. Pileni et al., submitted.). The angular dependence of the magnetization reversal could be explained approximately by simple classical micromagnetic concepts: uniform rotation and curling. However, our measurement evidenced nucleation and propagation of domain walls except for the smallest particles of about 20 nm. The switching field distributions as a function of temperature and field sweeping rate and the probabilities of switching showed that the magnetization reversal was thermally activated. These measurements allowed us to estimate the "activation volume" which triggered the magnetization reversal. Our measurements showed for the first time that the magnetization reversal of a ferromagnetic nanoparticle of good quality can be

  19. Modifications in Glass Ionomer Cements: Nano-Sized Fillers and Bioactive Nanoceramics

    Science.gov (United States)

    Najeeb, Shariq; Khurshid, Zohaib; Zafar, Muhammad Sohail; Khan, Abdul Samad; Zohaib, Sana; Martí, Juan Manuel Nuñez; Sauro, Salvatore; Matinlinna, Jukka Pekka; Rehman, Ihtesham Ur

    2016-01-01

    Glass ionomer cements (GICs) are being used for a wide range of applications in dentistry. In order to overcome the poor mechanical properties of glass ionomers, several modifications have been introduced to the conventional GICs. Nanotechnology involves the use of systems, modifications or materials the size of which is in the range of 1–100 nm. Nano-modification of conventional GICs and resin modified GICs (RMGICs) can be achieved by incorporation of nano-sized fillers to RMGICs, reducing the size of the glass particles, and introducing nano-sized bioceramics to the glass powder. Studies suggest that the commercially available nano-filled RMGIC does not hold any significant advantage over conventional RMGICs as far as the mechanical and bonding properties are concerned. Conversely, incorporation of nano-sized apatite crystals not only increases the mechanical properties of conventional GICs, but also can enhance fluoride release and bioactivity. By increasing the crystallinity of the set matrix, apatites can make the set cement chemically more stable, insoluble, and improve the bond strength with tooth structure. Increased fluoride release can also reduce and arrest secondary caries. However, due to a lack of long-term clinical studies, the use of nano-modified glass ionomers is still limited in daily clinical dentistry. In addition to the in vitro and in vivo studies, more randomized clinical trials are required to justify the use of these promising materials. The aim of this paper is to review the modification performed in GIC-based materials to improve their physicochemical properties. PMID:27428956

  20. Constrained Geometry Organotitanium Catalysts Supported on Nanosized Silica for Ethylene (co)Polymerization.

    Science.gov (United States)

    Li, Kuo-Tseng; Wu, Ling-Huey

    2017-05-05

    Supported olefin polymerization catalysts can prevent reactor-fouling problems and produce uniform polymer particles. Constrained geometry complexes (CGCs) have less sterically hindered active sites than bis-cyclopentadienyl metallocene catalysts. In the literature, micrometer-sized silica particles were used for supporting CGC catalysts, which might have strong mass transfer limitations. This study aims to improve the activity of supported CGC catalysts by using nanometer-sized silica. Ti[(C₅Me₄)SiMe₂(N t Bu)]Cl₂, a "constrained-geometry" titanium catalyst, was supported on MAO-treated silicas (nano-sized and micro-sized) by an impregnation method. Ethylene homo-polymerization and co-polymerization with 1-octene were carried out in a temperature range of 80-120 °C using toluene as the solvent. Catalysts prepared and polymers produced were characterized. For both catalysts and for both reactions, the maximum activities occurred at 100 °C, which is significantly higher than that (60 °C) reported before for supported bis-cyclopentadienyl metallocene catalysts containing zirconium, and is lower than that (≥140 °C) used for unsupported Ti[(C₅Me₄)SiMe₂(N t Bu)]Me₂ catalyst. Activities of nano-sized catalyst were 2.6 and 1.6 times those of micro-sized catalyst for homopolymerization and copolymerization, respectively. The former produced polymers with higher crystallinity and melting point than the latter. In addition, copolymer produced with nanosized catalyst contained more 1-octene than that produced with microsized catalyst.

  1. Nano-sized cosmetic formulations or solid nanoparticles in sunscreens: a risk to human health?

    Science.gov (United States)

    Nohynek, Gerhard J; Dufour, Eric K

    2012-07-01

    Personal care products (PCP) often contain micron- or nano-sized formulation components, such as nanoemulsions or microscopic vesicles. A large number of studies suggest that such vesicles do not penetrate human skin beyond the superficial layers of the stratum corneum. Nano-sized PCP formulations may enhance or reduce skin absorption of ingredients, albeit at a limited scale. Modern sunscreens contain insoluble titanium dioxide (TiO₂) or zinc oxide (ZnO) nanoparticles (NP), which are efficient filters of UV light. A large number of studies suggest that insoluble NP do not penetrate into or through human skin. A number of in vivo toxicity tests, including in vivo intravenous studies, showed that TiO₂ and ZnO NP are non-toxic and have an excellent skin tolerance. Cytotoxicity, genotoxicity, photo-genotoxicity, general toxicity and carcinogenicity studies on TiO₂ and ZnO NP found no difference in the safety profile of micro- or nano-sized materials, all of which were found to be non-toxic. Although some published in vitro studies on insoluble nano- or micron-sized particles suggested cell uptake, oxidative cell damage or genotoxicity, these data are consistent with those from micron-sized particles and should be interpreted with caution. Data on insoluble NP, such as surgical implant-derived wear debris particles or intravenously administered magnetic resonance contrast agents suggest that toxicity of small particles is generally related to their chemistry rather than their particle size. Overall, the weight of scientific evidence suggests that insoluble NP used in sunscreens pose no or negligible risk to human health, but offer large health benefits, such as the protection of human skin against UV-induced skin ageing and cancer.

  2. Silicon-based photocells of enhanced spectral sensitivity with nano-sized graded band gap structures

    International Nuclear Information System (INIS)

    Bakhadyrkhanov, M.K.; Isamov, S.B.; Iliev, K.M. et al.

    2014-01-01

    Photoelectric properties of monocrystalline silicon with multiply charged nanoclusters are studied that generate 'silicon clusters', i.e., nano-sized graded band gap structures. Multiply charged nanoclusters of manganese atoms strongly influence the photoelectric properties of monocrystalline silicon and expand the range of spectral sensitivity up to 8 μm; the photoelectric sensitivity reaches ∼10 9 . Conditions occur for the emergence of photo-emf in such a material in the infrared region when hν< E g . The obtained experimental data expand the functional capabilities for the application of silicon with multiply charged impurity atoms. (authors)

  3. Identification and characterization of the nano-sized vesicles released by muscle cells.

    Science.gov (United States)

    Romancino, Daniele P; Paterniti, Gaetano; Campos, Yvan; De Luca, Angela; Di Felice, Valentina; d'Azzo, Alessandra; Bongiovanni, Antonella

    2013-05-02

    Several cell types secrete small membranous vesicles that contain cell-specific collections of proteins, lipids, and genetic material. The function of these vesicles is to allow cell-to-cell signaling and the horizontal transfer of their cargo molecules. Here, we demonstrate that muscle cells secrete nano-sized vesicles and that their release increases during muscle differentiation. Analysis of these nanovesicles allowed us to characterize them as exosome-like particles and to define the potential role of the multifunctional protein Alix in their biogenesis. Copyright © 2013 Federation of European Biochemical Societies. All rights reserved.

  4. Thermodynamics of disaggregated polymer composites based on nanosized powders of Ni and NiO

    Directory of Open Access Journals (Sweden)

    N. S. Volodina

    2015-03-01

    Full Text Available Technique to obtain disaggregated composites with uniform distribution of the Ni nanoparticles in a polymer matrix was developed on the example of epoxy resin. Disaggregated and aggregated composites based on butyl methacrylate copolymer with 5 wt% methacrylic acid and Ni and NiO nanoparticles were obtained. Enthalpies of mixing the components compositions in a wide range of compositions were defined using isothermal calorimetry. Parameters adhesive interaction at the interface and glassy polymer structure changes were calculated. The influence of the chemical nature of nanosized filler on interfacial energy was found.

  5. Nanoscale Design of Nano-Sized Particles in Shape-Memory Polymer Nanocomposites Driven by Electricity

    Directory of Open Access Journals (Sweden)

    Kai Yu

    2013-09-01

    Full Text Available In the last few years, we have witnessed significant progress in developing high performance shape memory polymer (SMP nanocomposites, in particular, for shape recovery activated by indirect heating in the presence of electricity, magnetism, light, radio frequency, microwave and radiation, etc. In this paper, we critically review recent findings in Joule heating of SMP nanocomposites incorporated with nanosized conductive electromagnetic particles by means of nanoscale control via applying an electro- and/or magnetic field. A few different nanoscale design principles to form one-/two-/three- dimensional conductive networks are discussed.

  6. Synthesis of nano-sized β-tricalcium phosphate via wet precipitation

    Directory of Open Access Journals (Sweden)

    Bahman Mirhadi

    2011-12-01

    Full Text Available Nano-size β-tricalcium phosphate powders with average grain size of 50 nm were prepared by the wet chemical precipitation method with calcium nitrate and diammonium hydrogen phosphate as calcium and phosphorus precursors, respectively. The pH of the system was maintained at 8 and 10.8 by adding of sodium hydroxide. Filtered cake was dried at 80°C and calcined at 700°C. The dried and calcined powders were characterized using X-ray diffractrometry (XRD, Fourier transform infrared spectroscopy (FTIR, inductively coupled plasma atomic emission spectroscopy (ICPAES and scanning electron microscopy (SEM.

  7. Mechanical properties of silicone composites reinforced with micron- and nano-sized magnetic particles

    Directory of Open Access Journals (Sweden)

    H. Zhang

    2013-06-01

    Full Text Available Silicone composites filled with different-sized nickel particles were prepared. By applying a permanent magnet, both the micron- and nano-sized particles were found to distribute along the magnetic field direction, resulting in chain-like microstructures, which improved the key mechanical properties of the resultant samples effectively, compared to the samples with randomly-distributed particles. The composites were also tested under various magnetic field strengths. The samples with aligned particles showed larger improvements in shear storage modulus than those with random particles.

  8. Presence of nano-sized silica during in vitro digestion of foods containing silica as a food additive.

    Science.gov (United States)

    Peters, Ruud; Kramer, Evelien; Oomen, Agnes G; Rivera, Zahira E Herrera; Oegema, Gerlof; Tromp, Peter C; Fokkink, Remco; Rietveld, Anton; Marvin, Hans J P; Weigel, Stefan; Peijnenburg, Ad A C M; Bouwmeester, Hans

    2012-03-27

    The presence, dissolution, agglomeration state, and release of materials in the nano-size range from food containing engineered nanoparticles during human digestion is a key question for the safety assessment of these materials. We used an in vitro model to mimic the human digestion. Food products subjected to in vitro digestion included (i) hot water, (ii) coffee with powdered creamer, (iii) instant soup, and (iv) pancake which either contained silica as the food additive E551, or to which a form of synthetic amorphous silica or 32 nm SiO(2) particles were added. The results showed that, in the mouth stage of the digestion, nano-sized silica particles with a size range of 5-50 and 50-500 nm were present in food products containing E551 or added synthetic amorphous silica. However, during the successive gastric digestion stage, this nano-sized silica was no longer present for the food matrices coffee and instant soup, while low amounts were found for pancakes. Additional experiments showed that the absence of nano-sized silica in the gastric stage can be contributed to an effect of low pH combined with high electrolyte concentrations in the gastric digestion stage. Large silica agglomerates are formed under these conditions as determined by DLS and SEM experiments and explained theoretically by the extended DLVO theory. Importantly, in the subsequent intestinal digestion stage, the nano-sized silica particles reappeared again, even in amounts higher than in the saliva (mouth) digestion stage. These findings suggest that, upon consumption of foods containing E551, the gut epithelium is most likely exposed to nano-sized silica. © 2012 American Chemical Society

  9. Nanosized rods agglomerates as a new approach for formulation of a dry powder inhaler.

    Science.gov (United States)

    Salem, Hf; Abdelrahim, Me; Eid, K Abo; Sharaf, Ma

    2011-01-01

    Nanosized dry powder inhalers provide higher stability for poorly water-soluble drugs as compared with liquid formulations. However, the respirable particles must have a diameter of 1-5 μm in order to deposit in the lungs. Controlled agglomeration of the nanoparticles increases their geometric particle size so they can deposit easily in the lungs. In the lungs, they fall apart to reform nanoparticles, thus enhancing the dissolution rate of the drugs. Theophylline is a bronchodilator with poor solubility in water. Nanosized theophylline colloids were formed using an amphiphilic surfactant and destabilized using dilute sodium chloride solutions to form the agglomerates. The theophylline nanoparticles thus obtained had an average particle size of 290 nm and a zeta potential of -39.5 mV, whereas the agglomerates were 2.47 μm in size with a zeta potential of -28.9 mV. The release profile was found to follow first-order kinetics (r(2) > 0.96). The aerodynamic characteristics of the agglomerated nanoparticles were determined using a cascade impactor. The behavior of the agglomerate was significantly better than unprocessed raw theophylline powder. In addition, the nanoparticles and agglomerates resulted in a significant improvement in the dissolution of theophylline. The results obtained lend support to the hypothesis that controlled agglomeration strategies provide an efficient approach for the delivery of poorly water-soluble drugs into the lungs.

  10. Snow-borne nanosized particles: Abundance, distribution, composition, and significance in ice nucleation processes

    Science.gov (United States)

    Rangel-Alvarado, Rodrigo Benjamin; Nazarenko, Yevgen; Ariya, Parisa A.

    2015-11-01

    Physicochemical processes of nucleation constitute a major uncertainty in understanding aerosol-cloud interactions. To improve the knowledge of the ice nucleation process, we characterized physical, chemical, and biological properties of fresh snow using a suite of state-of-the-art techniques based on mass spectrometry, electron microscopy, chromatography, and optical particle sizing. Samples were collected at two North American Arctic sites, as part of international campaigns (2006 and 2009), and in the city of Montreal, Canada, over the last decade. Particle size distribution analyses, in the range of 3 nm to 10 µm, showed that nanosized particles are the most numerous (38-71%) in fresh snow, with a significant portion (11 to 19%) less than 100 nm in size. Particles with diameters less than 200 nm consistently exhibited relatively high ice-nucleating properties (on average ranged from -19.6 ± 2.4 to -8.1 ± 2.6°C). Chemical analysis of the nanosized fraction suggests that they contain bioorganic materials, such as amino acids, as well as inorganic compounds with similar characteristics to mineral dust. The implication of nanoparticle ubiquity and abundance in diverse snow ecosystems are discussed in the context of their importance in understanding atmospheric nucleation processes.

  11. A new nano-sized iron oxide particle with high sensitivity for cellular magnetic resonance imaging.

    Science.gov (United States)

    Chen, Chih-Lung; Zhang, Haosen; Ye, Qing; Hsieh, Wen-Yuan; Hitchens, T Kevin; Shen, Hsin-Hsin; Liu, Li; Wu, Yi-Jen; Foley, Lesley M; Wang, Shian-Jy; Ho, Chien

    2011-10-01

    In this study, we investigated the labeling efficiency and magnetic resonance imaging (MRI) signal sensitivity of a newly synthesized, nano-sized iron oxide particle (IOP) coated with polyethylene glycol (PEG), designed by Industrial Technology Research Institute (ITRI). Macrophages, bone-marrow-derived dendritic cells, and mesenchymal stem cells (MSCs) were isolated from rats and labeled by incubating with ITRI-IOP, along with three other iron oxide particles in different sizes and coatings as reference. These labeled cells were characterized with transmission electron microscopy (TEM), light and fluorescence microscopy, phantom MRI, and finally in vivo MRI and ex vivo magnetic resonance microscopy (MRM) of transplanted hearts in rats infused with labeled macrophages. The longitudinal (r (1)) and transverse (r (2)) relaxivities of ITRI-IOP are 22.71 and 319.2 s(-1) mM(-1), respectively. TEM and microscopic images indicate the uptake of multiple ITRI-IOP particles per cell for all cell types. ITRI-IOP provides sensitivity comparable or higher than the other three particles shown in phantom MRI. In vivo MRI and ex vivo MRM detect punctate spots of hypointensity in rejecting hearts, most likely caused by the accumulation of macrophages labeled by ITRI-IOP. ITRI-IOP, the nano-sized iron oxide particle, shows high efficiency in cell labeling, including both phagocytic and non-phagocytic cells. Furthermore, it provides excellent sensitivity in T(2)*-weighted MRI, and thus can serve as a promising contrast agent for in vivo cellular MRI.

  12. Vaccine delivery system for tuberculosis based on nano-sized hepatitis B virus core protein particles.

    Science.gov (United States)

    Dhanasooraj, Dhananjayan; Kumar, R Ajay; Mundayoor, Sathish

    2013-01-01

    Nano-sized hepatitis B virus core virus-like particles (HBc-VLP) are suitable for uptake by antigen-presenting cells. Mycobacterium tuberculosis antigen culture filtrate protein 10 (CFP-10) is an important vaccine candidate against tuberculosis. The purified antigen shows low immune response without adjuvant and tends to have low protective efficacy. The present study is based on the assumption that expression of these proteins on HBc nanoparticles would provide higher protection when compared to the native antigen alone. The cfp-10 gene was expressed as a fusion on the major immunodominant region of HBc-VLP, and the immune response in Balb/c mice was studied and compared to pure proteins, a mixture of antigens, and fusion protein-VLP, all without using any adjuvant. The humoral, cytokine, and splenocyte cell proliferation responses suggested that the HBc-VLP bearing CFP-10 generated an antigen-specific immune response in a Th1-dependent manner. By virtue of its self-adjuvant nature and ability to form nano-sized particles, HBc-VLPs are an excellent vaccine delivery system for use with subunit protein antigens identified in the course of recent vaccine research.

  13. Possible role of nano-sized particles in chronic tonsillitis and tonsillar carcinoma: a pilot study.

    Science.gov (United States)

    Zeleník, Karol; Kukutschová, Jana; Dvořáčková, Jana; Bielniková, Hana; Peikertová, Pavlína; Cábalová, Lenka; Komínek, Pavel

    2013-02-01

    This study aimed to evaluate the palatine tonsils of patients with chronic tonsillitis and spinocellular carcinoma to determine the presence of nano-sized particles. Tonsil samples from adult patients with chronic tonsillitis and spinocellular carcinoma of the palatine tonsil were dried and analyzed using a scanning electron microscope with the X-ray microprobe of an energy-dispersive spectroscope. Demographic data and smoking histories were obtained. The principal metals found in almost all tissues analyzed were iron, chromium, nickel, aluminum, zinc, and copper. No significant difference in elemental composition was found between the group of patients with chronic tonsillitis and the group with spinocellular carcinoma of the palatine tonsil. Likewise, no significant difference was found between the group of smokers and the group of nonsmokers. The presence of various micro- and nano-sized metallic particles in human tonsils was confirmed. These particles may potentially cause an inflammatory response as well as neoplastic changes in human palatine tonsils similar to those occurring in the lungs. Further and more detailed studies addressing this issue, including studies designed to determine the chemical form of the metals detected, studies devoted to quantitative analysis, biokinetics, and to the degradation and elimination of nanoparticles are needed for a more detailed prediction of the relation between the diagnosis and the presence of specific metal nanoparticles in tonsillar tissue.

  14. Structure of Nano-sized CeO2 Materials: Combined Scattering and Spectroscopic Investigations.

    Science.gov (United States)

    Marchbank, Huw R; Clark, Adam H; Hyde, Timothy I; Playford, Helen Y; Tucker, Matthew G; Thompsett, David; Fisher, Janet M; Chapman, Karena W; Beyer, Kevin A; Monte, Manuel; Longo, Alessandro; Sankar, Gopinathan

    2016-11-04

    The structure of several nano-sized ceria, CeO 2 , systems was investigated using neutron and X-ray diffraction and X-ray absorption spectroscopy. Whilst both diffraction and total pair distribution functions (PDFs) revealed that in all of the samples the occupancy of both Ce 4+ and O 2- are very close to the ideal stoichiometry, the analysis using Reverse Monte Carlo technique revealed significant disorder around oxygen atoms in the nano-sized ceria samples in comparison to the highly crystalline NIST standard. In addition, the analysis revealed that the main differences observed in the pair correlations from various X-ray and neutron diffraction techniques were attributable to the particle size of the CeO 2 prepared by the reported three methods. Furthermore, detailed analysis of the Ce L 3 - and K-edge EXAFS data support this finding; in particular the decrease in higher shell coordination numbers with respect to the NIST standard, is attributed to differences in particle size. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Mixing and Characterization of Nanosized Powders: An Assessment of Different Techniques

    International Nuclear Information System (INIS)

    Wei Dongguang; Dave, Rajesh; Pfeffer, Robert

    2002-01-01

    The objective of this paper was to gain an understanding of the mixing and characterization of nanosized powders. Three different nanosized material systems were selected based on their physical and chemical properties. Mixing experiments of the selected nanopowders were performed using a variety of environmentally friendly dry powder processing devices and the rapid expansion of supercritical CO 2 suspensions (RESS process) and compared with solvent-based methods coupled with ultrasonic agitation. A number of imaging techniques, including FESEM, AFM, TEM, EELS and EDS were used to characterize the degree of mixing or homogeneity of the mixtures obtained.The results indicate that only some of the imaging techniques are capable of determining the quality of nanoparticle mixing, depending on the physical and chemical properties of the nanopowders. For example, field emission scanning electron microscope (FESEM) is suitable for characterizing powder mixtures having a distinct difference in particle shape, or with a large difference in atomic number of the metallic element of the two constituents. Only electron energy loss spectroscopy (EELS) was able to fully characterize nanopowder mixtures of SiO 2 and TiO 2 at the nanoscale. Energy dispersive X-ray spectroscopy (EDS) provided information on mixing quality, but only on a scale of about 1 μm. The results also show that solvent-based mixing methods coupled with ultrasonic agitation, and RESS generally perform better than dry powder processing systems, with the exception of the hybridizer, in generating a homogeneous mixture

  16. Urban runoff treatment using nano-sized iron oxide coated sand with and without magnetic field applying.

    Science.gov (United States)

    Khiadani Hajian, Mehdi; Zarrabi, Mansur; Foroughi, Maryam

    2013-12-20

    Increase of impervious surfaces in urban area followed with increases in runoff volume and peak flow, leads to increase in urban storm water pollution. The polluted runoff has many adverse impacts on human life and environment. For that reason, the aim of this study was to investigate the efficiency of nano iron oxide coated sand with and without magnetic field in treatment of urban runoff. In present work, synthetic urban runoff was treated in continuous separate columns system which was filled with nano iron oxide coated sand with and without magnetic field. Several experimental parameters such as heavy metals, turbidity, pH, nitrate and phosphate were controlled for investigate of system efficiency. The prepared column materials were characterized with Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray analysis (EDXA) instruments. SEM and EDXA analyses proved that the sand has been coated with nano iron oxide (Fe3O4) successfully. The results of SEM and EDXA instruments well demonstrate the formation of nano iron oxide (Fe3O4) on sand particle. Removal efficiency without magnetic field for turbidity; Pb, Zn, Cd and PO4 were observed to be 90.8%, 73.3%, 75.8%, 85.6% and 67.5%, respectively. When magnetic field was applied, the removal efficiency for turbidity, Pb, Zn, Cd and PO4 was increased to 95.7%, 89.5%, 79.9%, 91.5% and 75.6% respectively. In addition, it was observed that coated sand and magnetic field was not able to remove NO3 ions. Statistical analyses of data indicated that there was a significant difference between removals of pollutants in two tested columns. Results of this study well demonstrate the efficiency of nanosized iron oxide-coated sand in treatment of urban runoff quality; upon 75% of pollutants could be removed. In addition, in the case of magnetic field system efficiency can be improved significantly.

  17. Hemimicelle capped functionalized carbon nanotubes-based nanosized solid-phase extraction of arsenic from environmental water samples

    International Nuclear Information System (INIS)

    Li Lu; Huang Yuming; Wang Yan; Wang Weidong

    2009-01-01

    The end functionalization of CNTs can introduce oxygen-containing negatively functional groups such as -COOH, -OH, or -C=O on their surface site. If cationic surfactant such as cetyltrimethylammonium chloride (CTAC) was added to the functionalized CNTs, then interactions such as hydrophobic and ionic may lead to formation of hemimicelle/admicelle aggregates on the CNTs, a new kind of adsorbents, namely, the hemimicelle capped CMMWCNTs, is obtained. The application of the hemimicelle capped carbon nanotubes-based nanosized solid-phase extraction (SPE) adsorbents in environmental analysis is reported for the first time using arsenic as model target. The effect of adsorption and desorption conditions for arsenic including the amount of surfactant, initial pH of sample solution, the ultrasonic time of sample solution, the amount of electrolyte, flow rate, eluent and its amount were investigated and optimized prior to its determination by atomic fluorescence spectrophotometry (AFS). Arsenic can be quantitatively retained on the hemimicelle capped CMMWCNTs at pH 5-6 from sample volume up to 500 mL and then eluted completely with 2 mol L -1 HNO 3 in the presence of 10 mg L -1 CTAC. The method detection limit for arsenic determination with AFS detection was 2 ng L -1 , and the relative standard deviation (RSD, n = 11) was 5.3% at the 0.5 μg L -1 level. The recoveries of arsenic in the spiked environmental water samples ranged from 94% to 104.29% with 500 mL of water sample. The proposed method has been applied successfully to the analysis of arsenic in aqueous environmental samples, which demonstrates the hemimicelle capped CMMWCNTs can be an excellent SPE adsorbents for arsenic pretreatment and enrichment from real water samples

  18. Toxicological aspects of photocatalytic degradation of selected xenobiotics with nano-sized Mn-doped TiO2.

    Science.gov (United States)

    Ozmen, Murat; Güngördü, Abbas; Erdemoglu, Sema; Ozmen, Nesrin; Asilturk, Meltem

    2015-08-01

    The toxic effects of two selected xenobiotics, bisphenol A (BPA) and atrazine (ATZ), were evaluated after photocatalytic degradation using nano-sized, Mn-doped TiO2. Undoped and Mn-doped TiO2 nanoparticles were synthesized. The samples were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), UV-vis-diffuse reflectance spectra (DRS), X-ray fluorescence spectroscopy (XRF), and BET surface area. The photocatalytic efficiency of the undoped and Mn-doped TiO2 was evaluated for BPA and ATZ. The toxicity of the synthesized photocatalysts and photocatalytic by-products of BPA and ATZ was determined using frog embryos and tadpoles, zebrafish embryos, and bioluminescent bacteria. Possible toxic effects were also evaluated using selected enzyme biomarkers. The results showed that Mn-doped TiO2 nanoparticles did not cause significant lethality in Xenopus laevis embryos and tadpoles, but nonfiltered samples caused lethality in zebrafish. Furthermore, Mn-doping of TiO2 increased the photocatalytic degradation capability of nanoparticles, and it successfully degraded BPA and AZT, but degradation of AZT caused an increase of the lethal effects on both tadpoles and fish embryos. Degradation of BPA caused a significant reduction of lethal effects, especially after 2-4h of degradation. However, biochemical assays showed that both Mn-doped TiO2 and the degradation by-products caused a significant change of selected biomarkers on X. laevis tadpoles; thus, the ecological risks of Mn-doped TiO2 should be considered due to nanomaterial applications and for spilled nanoparticles in an aquatic ecosystem. Also, the risk of nanoparticles should be considered using indicator reference biochemical markers to verify the environmental health impacts. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Experimental Study on the Deactivating Effect of KNO3, KCl, and K2SO4 on Nanosized Ceria/Titania SCR Catalyst

    Directory of Open Access Journals (Sweden)

    Xiongbo Chen

    2015-01-01

    Full Text Available Nanosized Ce/TiO2 is effective in selective catalytic reduction of NO with NH3. The NO conversion of Ce/TiO2 is 93% at 370°C. However, addition of potassium using KNO3, KCl, or K2SO4 as precursors effectively deactivates Ce/TiO2. NO conversion at 370°C is reduced to 45%, 24%, and 16% after addition of KNO3, KCl, and K2SO4, respectively, with a controlled K/Ce molar ration at 0.25. The deactivation may be attributed to the changes in the structural and chemical state of ceria and the degradation of surface acidity. The transformation of amorphous ceria into ceria crystals after potassium addition, together with the decrease of surface defects, is also determined. Oxygen diffusion in the process of ceria reduction is slow, and the redox cycle is slowed down. Moreover, the surface acid sites are markedly destroyed, leading to the reduced capacity of ammonia adsorption. These results may provide useful information for the application and life management of CeO2/TiO2 in potassium-rich environments such as biofuel-fired boilers.

  20. Nano-SiC region formation in (100) Si-on-insulator substrate: Optimization of hot-C+-ion implantation process to improve photoluminescence intensity

    Science.gov (United States)

    Mizuno, Tomohisa; Omata, Yuhsuke; Kanazawa, Rikito; Iguchi, Yusuke; Nakada, Shinji; Aoki, Takashi; Sasaki, Tomokazu

    2018-04-01

    We experimentally studied the optimization of the hot-C+-ion implantation process for forming nano-SiC (silicon carbide) regions in a (100) Si-on-insulator substrate at various hot-C+-ion implantation temperatures and C+ ion doses to improve photoluminescence (PL) intensity for future Si-based photonic devices. We successfully optimized the process by hot-C+-ion implantation at a temperature of about 700 °C and a C+ ion dose of approximately 4 × 1016 cm-2 to realize a high intensity of PL emitted from an approximately 1.5-nm-thick C atom segregation layer near the surface-oxide/Si interface. Moreover, atom probe tomography showed that implanted C atoms cluster in the Si layer and near the oxide/Si interface; thus, the C content locally condenses even in the C atom segregation layer, which leads to SiC formation. Corrector-spherical aberration transmission electron microscopy also showed that both 4H-SiC and 3C-SiC nanoareas near both the surface-oxide/Si and buried-oxide/Si interfaces partially grow into the oxide layer, and the observed PL photons are mainly emitted from the surface SiC nano areas.

  1. NANOSIZED MAGNESIUM OXIDE AS CATALYST FOR THE RAPID AND GREEN SYNTHESIS OF SUBSTITUTED 2-AMINO-2-CHROMENES

    Science.gov (United States)

    A nanosized magnesium oxide catalyzed three-component condensation reaction of aldehyde, malononitrile and ¿-naphthol proceeded rapidly in water/PEG to afford corresponding 2-amino-2-chromenes in high yields at room temperature. The greener protocol was found to be fairly general...

  2. A new approach to incorporating the effect of nano-sized dispersoids on recrystallization inhibition into Monte Carlo simulation

    NARCIS (Netherlands)

    Eivani, A. R.; Zhou, J.; Duszczyk, J.

    In this research, a new approach to incorporating the effect of nano-sized dispersoids on recrystallization was developed as a combination of physical modeling and Monte Carlo simulation. The energy stored during preceding deformation and the nucleation rate at the onset and during recrystallization

  3. Synthesis and characterization of nano-sized BaxSr1–xSO4 (0 ≤ x ...

    Indian Academy of Sciences (India)

    Administrator

    Synthesis and characterization of nano-sized BaxSr1–xSO4 (0 ≤ x ≤ 1) solid solution by a simple surfactant-free aqueous solution route. YU-FENG LI, JIA-HU OUYANG*, YU ZHOU, XUE-SONG LIANG and JI-YONG ZHONG. Institute for Advanced Ceramics, Department of Materials Science, Harbin Institute of Technology,.

  4. Presence of nano-sized silica during in vitro digestion of foods containing silica as a food additive.

    NARCIS (Netherlands)

    Peters, R.; Kramer, E.; Oomen, A.G.; Rivera, Z.E.; Oegema, G.; Tromp, P.C.; Fokkink, R.; Rietveld, A.; Marvin, H.J.; Weigel, S.; Peijnenburg, A.A.; Bouwmeester, H.

    2012-01-01

    The presence, dissolution, agglomeration state, and release of materials in the nano-size range from food containing engineered nanoparticles during human digestion is a key question for the safety assessment of these materials. We used an in vitro model to mimic the human digestion. Food products

  5. Presence of Nano-Sized Silica during In Vitro Digestion of Foods Containing Silica as a Food Additive

    NARCIS (Netherlands)

    Peters, R.J.B.; Kramer, E.H.M.; Oomen, A.G.; Rivera, Z.H.; Oegema, G.; Tromp, P.C.; Fokkink, R.G.; Rietveld, A.; Marvin, H.J.P.; Weigel, S.; Peijnenburg, A.A.C.M.; Bouwmeester, H.

    2012-01-01

    The presence, dissolution, agglomeration state, and release of materials in the nano-size range from food containing engineered nanoparticles during human digestion is a key question for the safety assessment of these materials. We used an in vitro model to mimic the human digestion. Food products

  6. Presence of nano-sized silica during in vitro digestion of foods containing silica as a food additive

    NARCIS (Netherlands)

    Peters, R.; Kramer, E.; Oomen, A.G.; Herrera Rivera, Z.E.; Oegema, G.; Tromp, P.C.; Fokkink, R.; Rietveld, A.; Marvin, H.J.P.; Weigel, S.; Peijnenburg, A.A.C.M.; Bouwmeester, H.

    2012-01-01

    The presence, dissolution, agglomeration state, and release of materials in the nano-size range from food containing engineered nanoparticles during human digestion is a key question for the safety assessment of these materials. We used an in vitro model to mimic the human digestion. Food products

  7. Nanosized TiO[subscript 2] for Photocatalytic Water Splitting Studied by Oxygen Sensor and Data Logger

    Science.gov (United States)

    Zhang, Ruinan; Liu, Song; Yuan, Hongyan; Xiao, Dan; Choi, Martin M. F.

    2012-01-01

    Photocatalytic water splitting by semiconductor photocatalysts has attracted considerable attention in the past few decades. In this experiment, nanosized titanium dioxide (nano-TiO[subscript 2]) particles are used to photocatalytically split water, which is then monitored by an oxygen sensor. Sacrificial reagents such as organics (EDTA) and metal…

  8. WC-Co COATINGS AND SINTERS MODIFIED WITH NANO-SIZED TiC MICROSTRUCTURE – QUANTITATIVE EVALUATION

    Directory of Open Access Journals (Sweden)

    Hanna Myalska

    2017-03-01

    Full Text Available The different concepts of WC-Co thermally sprayed coatings improvement may be considered and the application of nanoparticles, as the mechanical strengthening addition, is one of them. Nanostructured WC-Co coatings are characterized by higher hardness than the coatings formed from micrometric WC grains; whereas coatings with bimodal distribution of particles reveal greater wear resistance than the coatings obtained exclusively from nano-sized powders. Mixed effect of the matrix reinforcement by nanoparticles and strong fix of the micron-sized WC grains was proposed as a possible reason for enhanced wear resistance of bimodal coatings. In order to obtain a bimodal distribution of particles in the material standard WC-Co (83-17 powder was mixed with nanometric TiC powder (40-100 nm. The amount of TiC in powder mixtures was in the range from 1 to 7 wt.%. The mixtures were deposited on steel substrate using HVAF method and also hot pressed in vacuum. The microstructure of obtained coatings and sinters was quantitatively evaluated. Sinters revealed more homogenous distribution of the nano-sized TiC particles than the coatings. The addition of nano-sized TiC in the case of coatings has led to the decrease of its porosity. The agglomeration of nano-sized TiC particles in the coatings results in the decrease of material’s hardness.

  9. Tribological Behavior of Nano-Sized SiCp/7075 Composite Parts Formed by Semisolid Processing

    Directory of Open Access Journals (Sweden)

    Jufu Jiang

    2018-02-01

    Full Text Available The tribological behavior of the rheoformed and thixoformed nano-sized SiCp/7075 composite parts is investigated. The semisolid stirring temperature has a little influence on the friction coefficient and wear resistance of the rheoformed composite parts. As for the thixoformed composite parts, the average value of the steady-state coefficient of friction increases firstly and then decreases with increasing reheating temperature. Higher wear resistance is achieved at a reheating temperature of 580 °C. The average value of the steady-state friction coefficient of the rheoformed composite parts varies from 0.37 to 0.45 upon applied loads of from 20 to 50 N. Weight loss increases slightly upon an increase of applied load from 20 to 40 N. An applied load of 50 N leads to a significant increase of the weight loss. The wear rate decreases firstly and then increases with increasing applied load. As for the thixoformed composite part, the average value of the steady-state friction coefficient and the weight loss decreased with an increasing applied load. However, the wear rate decreases firstly with increasing applied load and then increases. As for the rheoformed composite part, the average value of the steady-state friction coefficient decreases firstly and then increases a little with increasing sliding velocity. Weight loss and wear rate show a first increase and a followed decrease with increasing sliding velocity. As for the thixoformed composite part, the average value of the steady-state friction coefficient shows a decrease with increasing sliding velocity. Weight loss and wear rate exhibit, at first, an increase, and then a decrease with increasing sliding velocity. The average friction coefficient varies from 0.4 to 0.44 with increasing volume fraction of SiC. Weight loss and wear rate decrease with increasing volume fraction of SiC. An increase in dislocation density around the nano-sized SiC particles and the mismatch of the coefficient of

  10. Design, modeling, expression, and chemoselective PEGylation of a new nanosize cysteine analog of erythropoietin

    Directory of Open Access Journals (Sweden)

    Ahangari Cohan R

    2011-06-01

    Full Text Available Reza Ahangari Cohan1, Armin Madadkar-Sobhani2,3, Hossein Khanahmad1, Farzin Roohvand4, Mohammad Reza Aghasadeghi4, Mohammad Hossein Hedayati5, Zahra Barghi5, Mehdi Shafiee Ardestani4, Davoud Nouri Inanlou1, Dariush Norouzian11Research and Development Department, Production and Research Complex, Pasteur Institute of Iran, Tehran, Iran; 2Department of Bioinformatics, Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran; 3Department of Life Sciences, Barcelona Supercomputing Center, Barcelona, Spain; 4Hepatitis and AIDS Department, Pasteur Institute of Iran, Tehran, Iran; 5Quality Control Department, Production and Research Complex, Pasteur Institute of Iran, Tehran, IranBackground: Recombinant human erythropoietin (rhEPO is considered to be one of the most pivotal pharmaceutical drugs in the market because of its clinical application in the treatment of anemia-associated disorders worldwide. However, like other therapeutic proteins, it does not have suitable pharmacokinetic properties for it to be administrated at least two to three times per week. Chemoselective cysteine PEGylation, employing molecular dynamics and graphics in in silico studies, can be considered to overcome such a problem.Methods: A special kind of EPO analog was elicited based on a literature review, homology modeling, molecular dynamic simulation, and factors affecting the PEGylation reaction. Then, cDNA of the selected analog was generated by site-directed mutagenesis and subsequently cloned into the expression vector. The construct was transfected to Chinese hamster ovary/dhfr- cells, and highly expressed clones were selected via methotrexate amplification. Ion-immobilized affinity and size exclusion (SE chromatography techniques were used to purify the expressed analog. Thereafter, chemoselective PEGylation was performed and a nanosize PEGylated EPO was obtained through dialysis. The in vitro biologic assay and in vivo pharmacokinetic parameters were

  11. Synthesis of nano-sized amorphous boron powders through active dilution self-propagating high-temperature synthesis method

    International Nuclear Information System (INIS)

    Wang, Jilin; Gu, Yunle; Li, Zili; Wang, Weimin; Fu, Zhengyi

    2013-01-01

    Graphical abstract: Nano-sized amorphous boron powders were synthesized by active dilution self-propagating high-temperature synthesis (SHS) method. The effects of endothermic reaction rate, the possible chemical reaction mechanism and active dilution model for synthesis of the product were also discussed. Highlights: ► Nano-sized amorphous boron powders were synthesized by active dilution self-propagating high-temperature synthesis method. ► The morphology, particle size and purity of the samples could be effectively controlled via changing the endothermic rate. ► The diluter KBH 4 played an important role in active dilution synthesis of amorphous nano-sized boron powders. ► The active dilution method could be further popularized and become a common approach to prepare various inorganic materials. - Abstract: Nano-sized amorphous boron powders were synthesized by active dilution self-propagating high-temperature synthesis (SHS) method at temperatures ranging from 700 °C to 850 °C in a SHS furnace using Mg, B 2 O 3 and KBH 4 as raw materials. Samples were characterized by X-ray powder diffraction (XRD), Laser particle size analyzer, Fourier transform infrared spectra (FTIR), X-ray energy dispersive spectroscopy (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission TEM (HRTEM). The boron powders demonstrated an average particle size of 50 nm with a purity of 95.64 wt.%. The diluter KBH 4 played an important role in the active dilution synthesis of amorphous nano-sized boron powders. The effects of endothermic reaction rate, the possible chemical reaction mechanism and active dilution model for synthesis of the product were also discussed

  12. An engineered polypeptide around nano-sized manganese-calcium oxide: copying plants for water oxidation.

    Science.gov (United States)

    Najafpour, Mohammad Mahdi; Ghobadi, Mohadeseh Zarei; Sarvi, Bahram; Haghighi, Behzad

    2015-09-14

    Synthesis of new efficient catalysts inspired by Nature is a key goal in the production of clean fuel. Different compounds based on manganese oxide have been investigated in order to find their water-oxidation activity. Herein, we introduce a novel engineered polypeptide containing tyrosine around nano-sized manganese-calcium oxide, which was shown to be a highly active catalyst toward water oxidation at low overpotential (240 mV), with high turnover frequency of 1.5 × 10(-2) s(-1) at pH = 6.3 in the Mn(III)/Mn(IV) oxidation range. The compound is a novel structural and efficient functional model for the water-oxidizing complex in Photosystem II. A new proposed clever strategy used by Nature in water oxidation is also discussed. The new model of the water-oxidizing complex opens a new perspective for synthesis of efficient water-oxidation catalysts.

  13. Nanoscaffold matrices for size-controlled, pulsatile transdermal testosterone delivery: nanosize effects on the time dimension

    Science.gov (United States)

    Malik, Ritu; Tondwal, Shailesh; Venkatesh, K. S.; Misra, Amit

    2008-10-01

    Pulsatile transdermal testosterone (T) has applications in hormone supplementation and male contraception. Pulsatile T delivery was achieved by assembling crystalline and nanoparticulate T in nucleation-inhibiting polymer matrices of controlled porosity. Different interference patterns observed from various polymeric films containing T were due to the various particle sizes of T present in the polymer matrices. Scanning electron microscopy was used to determine the size and shape of T crystals. Skin-adherent films containing T nanoparticles of any size between 10-500 nm could be prepared using pharmaceutically acceptable vinylic polymers. Drug release and skin permeation profiles were studied. The dissolution-diffusion behavior of nanoparticles differed from crystalline and molecular states. Nanosize may thus be used to engineer chronopharmacologically relevant drug delivery.

  14. Nanosized graphene sheets enhanced photoelectric behavior of carbon film on p-silicon substrate

    International Nuclear Information System (INIS)

    Yang, Lei; Hu, Gaijuan; Zhang, Dongqing; Diao, Dongfeng

    2016-01-01

    We found that nanosized graphene sheets enhanced the photoelectric behavior of graphene sheets embedded carbon (GSEC) film on p-silicon substrate, which was deposited under low energy electron irradiation in electron cyclotron resonance plasma. The GSEC/p-Si photodiode exhibited good photoelectric performance with photoresponsivity of 206 mA/W, rise and fall time of 2.2, and 4.3 μs for near-infrared (850 nm) light. The origin of the strong photoelectric behavior of GSEC film was ascribed to the appearance of graphene nanosheets, which led to higher barrier height and photoexcited electron-collection efficiency. This finding indicates that GSEC film has the potential for photoelectric applications.

  15. Spectroscopy of nanosized composites silicon-organic polymer/nanoporous silicas

    International Nuclear Information System (INIS)

    Ostapenko, N.; Kozlova, N.; Suto, S.; Watanabe, A.

    2006-01-01

    Fluorescence and excitation spectra (T=5-290 K) of nanosized silicon-organic polymers poly(di-n-hexylsilane) and poly(methyl(phenyl)silane) incorporated into porous silica materials MCM-41 and SBA-15 have been studied with varying pore diameter from 2.8 to 10 nm. The controlled variation of the pore diameter in a wide range (2.8-10 nm) permitted us, for the first time, to investigate the optical properties of the polymers on their transition from isolated macromolecules to a film. It is found that this transition depends on polymer type and occurs via the formation of new spatially independent structures of the polymers not observed in the spectra of the film, namely, via the formation of disordered and (or) ordered conformations of polymer chains and clusters

  16. Synthesis and characterization of nanosized MnZn ferrites via a modified hydrothermal method

    Science.gov (United States)

    Li, Mingling; Liu, Xiansong; Xu, Taotao; Nie, Yu; Li, Honglin; Zhang, Cong

    2017-10-01

    Nanosized MnZn ferrite particles, with narrow size distribution, regular morphology and high saturation magnetization have been synthesized via a modified hydrothermal method. This modified hydrothermal method involves a chemical co-precipitation of hydroxides under a vacuum condition using potassium hydroxide as precipitating agent, followed by a separate hydrothermal process. The microstructure and magnetic properties of the synthesized nanoparticles were investigated by X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM) and vibrating sample magnetometer (VSM). The effects of different synthesis conditions (excess ratio of precipitating agent and hydrothermal reaction time) on the microstructure and magnetic properties of the as-synthesized nanoparticles were discussed. The magnetic measurements indicated that the obtained samples were superparamagnetic in nature at room temperature. Moreover, the MnZn ferrite nanoparticles with excellent magnetic performance could be synthesized at 180 °C for a short reaction time (3 h).

  17. Synthesis and Characterization of Nano-Sized zn Powder by Electrical Explosion of Wire in Liquid

    Science.gov (United States)

    Goo, W. H.; Bac, L. H.; Park, E. J.; Kim, J. S.; Kim, J. C.; Jung, H. S.; Lee, H. D.

    Zn powder has been used for many years as anticorrosive pigments in various paints. In this work, the nano-sized Zn powder was synthesized by wire explosion method in deionised water and ethanol. The morphology of the prepared powders was observed by field emission-scanning electron microscopy (FE-SEM) and the oxidation of the powders was determined using energy-dispersive X-ray spectroscopy (EDS). The size of particles was estimated from transmission electron microscopy (TEM) and FE-SEM. Dispersion properties of the as-prepared Zn nanoparticles in ethanol were evaluated by Turbiscan lab device. It is found that Zn nanoparticle prepared in ethanol had spherical shape with average particles size ~150 nm while the one prepared in water had a mixture of hexagonal and spherical shape. Ethanol can reduce the oxidation of Zn nanoparticles in comparison with water. Stability of Zn nanoparticles dispersed in ethanol exhibited the agglomeration in the dispersion.

  18. Ferromagnetic resonance of micro- and nano-sized hexagonal ferrite powders at millimeter waves

    Science.gov (United States)

    Korolev, Konstantin A.; McCloy, John S.; Afsar, Mohammed N.

    2012-04-01

    Complex magnetic permeability and dielectric permittivity of micro- and nano-sized powdered barium (BaFe12O19) and strontium (SrFe12O19) hexaferrites have been studied in a broadband millimeter wave frequency range (30-120 GHz). Transmittance measurements have been performed using a free-space quasi-optical millimeter wave spectrometer, equipped with a set of high-power backward wave oscillators. Real and imaginary parts of dielectric permittivity for both types of micro- and nanoferrites have been calculated using analysis of recorded high-precision transmittance spectra. Frequency dependences of the magnetic permeability have been obtained from Schlömann's equation for partially magnetized ferrites. These materials show promise as tunable millimeter wave absorbers, based on their size-dependent absorption.

  19. Ferromagnetic Resonance of Micro- and Nano-sized Hexagonal Ferrite Powders at Millimeter Waves

    Energy Technology Data Exchange (ETDEWEB)

    Korolev, Konstantin A.; McCloy, John S.; Afsar, Mohammed N.

    2012-02-22

    Complex magnetic permeability and dielectric permittivity of micro- and nano-sized powdered barium (BaFe{sub 12}O{sub 19}) and strontium (SrFe{sub 12}O{sub 19}) hexaferrites have been studied in a broadband millimeter wave frequency range (30-120 GHz). Transmittance measurements have been performed using a free space quasi-optical millimeter wave spectrometer, equipped with a set of high power backward wave oscillators. Real and imaginary parts of dielectric permittivity for both types of micro- and nanoferrites have been calculated using analysis of recorded high precision transmittance spectra. Frequency dependences of the magnetic permeability have been obtained from Schloemann's equation for partially magnetized ferrites. These materials show promise as tunable millimeter wave absorber, based on their size-dependent absorption.

  20. Detection of micro- and nano-sized biocompatible particles in the blood.

    Science.gov (United States)

    Gatti, A M; Montanari, S; Monari, E; Gambarelli, A; Capitani, F; Parisini, B

    2004-04-01

    The research deals with new scanning electron microscopic evaluations of the interface between blood and explanted temporary vena cava filters from patients affected by blood disorders. The biological tissues adherent to the filter and the small thrombi formed in vivo were detached from the metallic structure of the device, fixed, dehydrated and prepared for the histological and the electron microscopy. The analyses showed that both samples (thrombus and newly formed tissue) contained foreign, in some cases nano-sized, bodies. The chemistry of these particles was different and varied, and unusual compounds containing non-biocompatible elements like bismuth, lead, wolfram, tungsten were also detected. The interaction between these debris travelling in the blood stream and the blood itself leads to suspect that the formation of the thrombus can originate from these inorganic and inert foreign bodies that act as triggering agent of the blood coagulation.

  1. High reactivity of nanosized niobium oxide cluster cations in methane activation: A comparison with vanadium oxides.

    Science.gov (United States)

    Ding, Xun-Lei; Wang, Dan; Wu, Xiao-Nan; Li, Zi-Yu; Zhao, Yan-Xia; He, Sheng-Gui

    2015-09-28

    The reactions between methane and niobium oxide cluster cations were studied and compared to those employing vanadium oxides. Hydrogen atom abstraction (HAA) reactions were identified over stoichiometric (Nb2O5)N(+) clusters for N as large as 14 with a time-of-flight mass spectrometer. The reactivity of (Nb2O5)N(+) clusters decreases as the N increases, and it is higher than that of (V 2O5)N(+) for N ≥ 4. Theoretical studies were conducted on (Nb2O5)N(+) (N = 2-6) by density functional calculations. HAA reactions on these clusters are all favorable thermodynamically and kinetically. The difference of the reactivity with respect to the cluster size and metal type (Nb vs V) was attributed to thermodynamics, kinetics, the electron capture ability, and the distribution of the unpaired spin density. Nanosized Nb oxide clusters show higher HAA reactivity than V oxides, indicating that niobia may serve as promising catalysts for practical methane conversion.

  2. Asymmetric Bioconversion of Acetophenone in Nano-Sized Emulsion Using Rhizopus oryzae.

    Science.gov (United States)

    Li, Qingzhi; Shi, Yang; He, Le; Zhao, Hui

    2016-01-01

    The fungal morphologies and pellet sizes were controlled in acetophenone reduction by Rhizopus oryzae. The acetophenone conversion and (S)-phenylethanol enantiomeric excesses (e.e.) reached the peak after 72 h of incubation when using pellets with 0.54 mm diameter, which showed an excellent performance compared with suspended mycelia, clumps, and pellets with 0.65 or 0.75 mm diameter. Furthermore, nano-sized acetophenone was used as a substrate to improve the performances of biotransformation work. The results showed that the conversion of nanometric acetophenone and (S)-phenylethanol e.e. reached the maximum (both >99%) after 32 h of incubation when using 0.54 mm diameter pellets, at least 24 h in advance of the control group. On the other hand, Tween 80 and 1, 2-propylene glycol showed low or no toxicity to cells. In conclusion, pellets and acetophenone nanoemulsions synergistically result in superior performances of acetophenone reduction.

  3. Spectral tuning of a locally bent microfiber taper interferometer with a nanosized liquid crystal overlay.

    Science.gov (United States)

    Luo, Haimei; Wang, Changjing; Ji, Yinghua; Yuan, Wen; Zhang, Guoping; Wang, Yifan; Hong, Zehua; Wang, Xianping

    2016-09-10

    In this paper, the tuning characteristics of locally bent microfiber taper covered with a nanosized high-refractive-index liquid crystal (LC) layer under different temperatures and electric field intensities have been theoretically analyzed and experimentally investigated. A locally bent microfiber taper interferometer with a waist diameter of ∼3.72  μm is fabricated by using the flame brushing technique, followed by bending the transition region of the taper to form a modal interferometer and later by placing a ∼200  nm LC layer over the uniform taper waist region. Experimental results indicate that a high-efficiency thermal or electric tuning of an LC-coated locally bent microfiber taper interferometer could be achieved. This suggests a potential application of this device as tunable all-fiber photonic devices, such as filters, modulators, and sensing elements.

  4. High temperature electrochemical performance of nanosized LiFePO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Mestre-Aizpurua, F.; Palacin, M.R. [Institut de Ciencia de Materials de Barcelona (ICMAB-CSIC), Campus UAB E-08193, Bellaterra, Catalonia (Spain); Hamelet, S.; Masquelier, C. [Laboratoire de Reactivite et de Chimie des Solides, CNRS UMR 6007, Universite de Picardie Jules Verne, 33 Rue St. Leu, 80039 Amiens Cedex 9 (France)

    2010-10-01

    The electrochemical performance of LiFePO{sub 4} was tested at temperatures up to 150 C for micrometric and nanometric size samples. Among the latter, both highly defective samples obtained by direct precipitation and annealed samples were tested. The comparison of voltage composition profiles for these samples coupled to GITT experiments allowed to conclude that defects seem to be the major factor in inducing the solid solution behaviour at room temperature. Good capacity retention is exhibited upon prolonged cycling at 100 C in EC LiBOB electrolyte, also for nanosized samples that still maintain 75% of the initial capacity after 170 cycles. These results prove that the enhanced thermal stability of such electrolytes can be extended to temperatures much higher than those usually tested. (author)

  5. Tracking T-cells in vivo with a new nano-sized MRI contrast agent.

    Science.gov (United States)

    Liu, Li; Ye, Qing; Wu, Yijen; Hsieh, Wen-Yuan; Chen, Chih-Lung; Shen, Hsin-Hsin; Wang, Shian-Jy; Zhang, Haosen; Hitchens, T Kevin; Ho, Chien

    2012-11-01

    Non-invasive in vivo tracking of T-cells by magnetic resonance imaging (MRI) can lead to a better understanding of many pathophysiological situations, including AIDS, cancer, diabetes, graft rejection. However, an efficient MRI contrast agent and a reliable technique to track non-phagocytic T-cells are needed. We report a novel superparamagnetic nano-sized iron-oxide particle, IOPC-NH2 series particles, coated with polyethylene glycol (PEG), with high transverse relaxivity (250 s(-1) mM(-1)), thus useful for MRI studies. IOPC-NH2 particles are the first reported magnetic particles that can label rat and human T-cells with over 90% efficiency, without using transfection agents, HIV-1 transactivator peptide, or electroporation. IOPC-NH2 particles do not cause any measurable effects on T-cell properties. Infiltration of IOPC-NH2-labeled T-cells can be detected in a rat model of heart-lung transplantation by in vivo MRI. IOPC-NH2 is potentially valuable contrast agents for labeling a variety of cells for basic and clinical cellular MRI studies, e.g., cellular therapy. In this study, a novel PEG coated superparamagnetic nano-sized iron-oxide particle was investigated as a T-cell labeling agent for MRI studies. The reported particles can label T-cells with over 90% efficiency, without using transfection agents, HIV-1 transactivator peptide, or electroporation, therefore may enable more convenient preclinical call labeling studies. Copyright © 2012 Elsevier Inc. All rights reserved.

  6. Acute Toxicity of Silver Free and Encapsulated in Nanosized Zeolite for Eukaryotic Cells.

    Science.gov (United States)

    Anfray, Clément; Dong, Biao; Komaty, Sarah; Mintova, Svetlana; Valable, Samuel

    2017-04-26

    The potential toxicity of encapsulated silver in EMT-type nanosized zeolites on prokaryotic cells, human tumor cell lines from various origins, and primary cultures of neurons and astrocytes was investigated. Silver in cationic form (Ag + ) was encapsulated in EMT-type nanosized zeolites via an ion exchange process (Ag + -EMT) and compared with the reduced silver (Ag 0 ) in the zeolite (Ag 0 -EMT). As reference samples for the toxicity measurements, pure EMT-type zeolite and silver perchlorate were used. Cells were exposed to silver-containing zeolites (50, 100, and 400 μg/mL) for 24 and 48 h. After exposure to Ag + -EMT (50 μg/mL) for 24 h, a loss in cell viability independent of the cell type was observed, ranging from -34.37 ± 23.90% for astrocytes to -99.5 ± 0.24% for U87-MG cells. These results were comparable with the toxicity for silver perchlorate. The Ag 0 -EMT sample showed lower toxicity on human cell lines in comparison to that of Ag + -EMT. A decrease in cell viability, i.e., -73.46 ± 20.78% and -62.3 ± 17.96% for U87-MG and HEK 293 cells, respectively, under exposure only to high concentration of Ag 0 -EMT (400 μg/mL) for 24 h was measured. However, the Ag 0 -EMT was as toxic as the Ag + -EMT for astrocytes and neurons (-97.95 ± 3.31% and -100 ± 1.11%, respectively, after exposure to 50 μg/mL for 24 h). No decrease in cell viability exposed to pure EMT zeolite was found. The results demonstrate the severe toxicity of silver cations, either free or encapsulated, in comparison to reduced silver encapsulated in zeolite nanocrystals. Therefore, silver cations, either free or encapsulated, must be used with great caution regarding their toxicity on eukaryotic cells.

  7. High Temperature Oxidation of Nickel-based Cermet Coatings Composed of Al2O3 and TiO2 Nanosized Particles

    Science.gov (United States)

    Farrokhzad, M. A.; Khan, T. I.

    2014-09-01

    New technological challenges in oil production require materials that can resist high temperature oxidation. In-Situ Combustion (ISC) oil production technique is a new method that uses injection of air and ignition techniques to reduce the viscosity of bitumen in a reservoir and as a result crude bitumen can be produced and extracted from the reservoir. During the in-situ combustion process, production pipes and other mechanical components can be exposed to air-like gaseous environments at extreme temperatures as high as 700 °C. To protect or reduce the surface degradation of pipes and mechanical components used in in-situ combustion, the use of nickel-based ceramic-metallic (cermet) coating produced by co-electrodeposition of nanosized Al2O3 and TiO2 have been suggested and earlier research on these coatings have shown promising oxidation resistance against atmospheric oxygen and combustion gases at elevated temperatures. Co-electrodeposition of nickel-based cermet coatings is a low-cost method that has the benefit of allowing both internal and external surfaces of pipes and components to be coated during a single electroplating process. Research has shown that the volume fraction of dispersed nanosized Al2O3 and TiO2 particles in the nickel matrix which affects the oxidation resistance of the coating can be controlled by the concentration of these particles in the electrolyte solution, as well as the applied current density during electrodeposition. This paper investigates the high temperature oxidation behaviour of novel nanostructured cermet coatings composed of two types of dispersed nanosized ceramic particles (Al2O3 and TiO2) in a nickel matrix and produced by coelectrodeposition technique as a function of the concentration of these particles in the electrolyte solution and applied current density. For this purpose, high temperature oxidation tests were conducted in dry air for 96 hours at 700 °C to obtain mass changes (per unit of area) at specific time

  8. Characterization of nano-sized oxides in Fe-12Cr oxide-dispersion-strengthened ferritic steel using small-angle neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Han, Young-Soo; Mao, Xiaodong; Jang, Jinsung; Kim, Tae-Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-04-01

    The ferritic ODS steel was manufactured by hot isostatic pressing and heat treatment. The nano-sized microstructures such as yttrium oxides and Cr oxides were quantitatively analyzed by small-angle neutron scattering (SANS). The effects of the fabrication conditions on the nano-sized microstructure were investigated in relation to the quantitative analysis results obtained by SANS. The ratio between magnetic and nuclear scattering components was calculated, and the characteristics of the nano-sized yttrium oxides are discussed based on the SANS analysis results. (orig.)

  9. Characterization of nano-sized oxides in Fe-12Cr oxide-dispersion-strengthened ferritic steel using small-angle neutron scattering

    International Nuclear Information System (INIS)

    Han, Young-Soo; Mao, Xiaodong; Jang, Jinsung; Kim, Tae-Kyu

    2015-01-01

    The ferritic ODS steel was manufactured by hot isostatic pressing and heat treatment. The nano-sized microstructures such as yttrium oxides and Cr oxides were quantitatively analyzed by small-angle neutron scattering (SANS). The effects of the fabrication conditions on the nano-sized microstructure were investigated in relation to the quantitative analysis results obtained by SANS. The ratio between magnetic and nuclear scattering components was calculated, and the characteristics of the nano-sized yttrium oxides are discussed based on the SANS analysis results. (orig.)

  10. Stabilization of nanosized titanium dioxide by cyclodextrin polymers and its photocatalytic effect on the degradation of wastewater pollutants.

    Science.gov (United States)

    Agócs, Tamás Zoltán; Puskás, István; Varga, Erzsébet; Molnár, Mónika; Fenyvesi, Éva

    2016-01-01

    Advanced oxidation processes (AOPs) are considered highly competitive water treatment technologies for the removal of organic pollutants. Among AOP techniques, photocatalysis has recently been the most widely studied. Our aims were to investigate how the dispersion of nanosized titanium dioxide (nanoTiO 2 ) applied in photodegradation-based procedures can be stabilized with cyclodextrins in order to obtain a new, more efficient photocatalyst for the purification of waters polluted by xenobiotics applying UV irradiation. During our work, on the one hand, we studied the behavior and stability of nanoTiO 2 in cyclodextrin solutions. On the other hand, we used various monomer and polymer cyclodextrin derivatives, and assessed the options for nanoTiO 2 stabilization in the presence of various salts and tap water on the basis of turbidity tests. The physical stability of nanoTiO 2 dispersions is diminished in the presence of the salts found in tap water (and occurring also in surface waters and ground water) and they are precipitated immediately. This colloidal instability can be improved by cyclodextrin derivatives. Based on the results of our studies we have selected carboxymethyl β-cyclodextrin polymer (CMBCD-P) for stabilization of nanoTiO 2 dispersions. The photocatalytic degradation of methylene blue and ibuprofen as model organic pollutants in various media (distilled water, NaCl solution and tap water) has been studied using nanoTiO 2 as catalyst stabilized by CMBCD-P. CMBCD-P itself showed a catalytic effect on the UV degradation of methylene blue. In addition to enhancing the colloid stability of nanoTiO 2 CMBCD-P showed also synergistic effects in catalyzing the photodecomposition process of the dye. On the other hand, ibuprofen as a model pharmaceutical, a pollutant of emerging concern (EP), was protected by CMBCD-P against the photocatalytic degradation showing that inclusion complex formation can result in opposite effects depending on the structure of the

  11. Toxicological aspects of photocatalytic degradation of selected xenobiotics with nano-sized Mn-doped TiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Ozmen, Murat, E-mail: murat.ozmen@inonu.edu.tr [Inonu University, Faculty of Science, Department of Biology, Malatya (Turkey); Güngördü, Abbas [Inonu University, Faculty of Science, Department of Biology, Malatya (Turkey); Erdemoglu, Sema [Inonu University, Faculty of Science, Department of Chemistry, Malatya (Turkey); Ozmen, Nesrin [Inonu University, Faculty of Education, Department of Science Teaching Program, Malatya (Turkey); Asilturk, Meltem [Akdeniz University, Department of Materials Science and Engineering, Antalya (Turkey)

    2015-08-15

    Highlights: • Undoped and Mn-doped TiO{sub 2} nanoparticles were synthesized and characterized. • The photocatalytic efficiency of the photocatalysts was evaluated for BPA and ATZ. • Toxicity of photocatalysts and photocatalytic by-products were determined. • Mn-doped TiO{sub 2} nanoparticles did not cause significant lethality on X. laevis. • Degradation of BPA caused a significant reduction of lethal effects. - Abstract: The toxic effects of two selected xenobiotics, bisphenol A (BPA) and atrazine (ATZ), were evaluated after photocatalytic degradation using nano-sized, Mn-doped TiO{sub 2}. Undoped and Mn-doped TiO{sub 2} nanoparticles were synthesized. The samples were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), UV–vis-diffuse reflectance spectra (DRS), X-ray fluorescence spectroscopy (XRF), and BET surface area. The photocatalytic efficiency of the undoped and Mn-doped TiO{sub 2} was evaluated for BPA and ATZ. The toxicity of the synthesized photocatalysts and photocatalytic by-products of BPA and ATZ was determined using frog embryos and tadpoles, zebrafish embryos, and bioluminescent bacteria. Possible toxic effects were also evaluated using selected enzyme biomarkers. The results showed that Mn-doped TiO{sub 2} nanoparticles did not cause significant lethality in Xenopus laevis embryos and tadpoles, but nonfiltered samples caused lethality in zebrafish. Furthermore, Mn-doping of TiO{sub 2} increased the photocatalytic degradation capability of nanoparticles, and it successfully degraded BPA and AZT, but degradation of AZT caused an increase of the lethal effects on both tadpoles and fish embryos. Degradation of BPA caused a significant reduction of lethal effects, especially after 2–4 h of degradation. However, biochemical assays showed that both Mn-doped TiO{sub 2} and the degradation by-products caused a significant change of selected biomarkers on X. laevis tadpoles; thus, the ecological risks of Mn

  12. Microstructure and corrosion resistance of Ni-based alloy laser coatings with nanosize CeO2 addition

    Science.gov (United States)

    Zhang, Shi Hong; Li, Ming Xi; Yoon, Jae Hong; Cho, Tong Yul; Zhu He, Yi; Lee, Chan Gyu

    2008-07-01

    Micron-size Ni-base alloy (NBA) powders were mixed with both 1.5 wt.% (hereinafter %) micron-size CeO2 (m-CeO2) and also 1.5% and 3.0% nano-size CeO2 (n- CeO2) powders. These mixtures were coated on low-carbon steel (Q235) by 2.0 kW CO2 laser cladding. The effects on the microstructures, phases and electrochemical corrosion of the coatings upon the addition of m- and n- CeO2 powders to NBA (m- and n- CeO2 /NBA) have been investigated. The results showed that a smooth coating was prepared under suitable processing parameters (P= 2.0 kW, V= 180 mm min- 1) by adding 1.5% n- CeO2. In addition to the primary phases of γ-Ni, Cr23 C6 and Ni3 B in the Ni-base alloy coating, CeNi3 was formed in Ni-base alloy coatings with both n- CeO2 and m-CeO2 particles, and CeNi5 appeared in the coating upon decreasing the size of CeO2 particles. Well-developed dendrites were observed in the Ni-base alloy coating; directional dendrites grew at the interface in the coating upon the addition of m-CeO2, whereas fine and multioriented dendrites grew upon decreasing the size of CeO2 particles to the nanoscale. Actinomorphic dendrites and compact equiaxed dendrites grew from the interface to near the surface upon increasing the content of n- CeO2 from 1.5 to 3.0%. In strongly acidic HNO3 solution, the severe corrosion of dendrites occurred and there were many corrosion pits in the Ni-base alloy coating; intercrystalline corrosion also has a dominant role upon the addition of m-CeO2, whereas uniform corrosion occurs in the coating as the size of CeO2 particles is decreased to nanoscale.

  13. Microstructure and corrosion resistance of Ni-based alloy laser coatings with nanosize CeO2 addition

    Directory of Open Access Journals (Sweden)

    Shi Hong Zhang et al

    2008-01-01

    Full Text Available Micron-size Ni-base alloy (NBA powders were mixed with both 1.5 wt.% (hereinafter % micron-size CeO2 (m-CeO2 and also 1.5% and 3.0% nano-size CeO2 (n- CeO2 powders. These mixtures were coated on low-carbon steel (Q235 by 2.0 kW CO2 laser cladding. The effects on the microstructures, phases and electrochemical corrosion of the coatings upon the addition of m- and n- CeO2 powders to NBA (m- and n- CeO2 /NBA have been investigated. The results showed that a smooth coating was prepared under suitable processing parameters (P= 2.0 kW, V= 180 mm min- 1 by adding 1.5% n- CeO2. In addition to the primary phases of γ-Ni, Cr23 C6 and Ni3 B in the Ni-base alloy coating, CeNi3 was formed in Ni-base alloy coatings with both n- CeO2 and m-CeO2 particles, and CeNi5 appeared in the coating upon decreasing the size of CeO2 particles. Well-developed dendrites were observed in the Ni-base alloy coating; directional dendrites grew at the interface in the coating upon the addition of m-CeO2, whereas fine and multioriented dendrites grew upon decreasing the size of CeO2 particles to the nanoscale. Actinomorphic dendrites and compact equiaxed dendrites grew from the interface to near the surface upon increasing the content of n- CeO2 from 1.5 to 3.0%. In strongly acidic HNO3 solution, the severe corrosion of dendrites occurred and there were many corrosion pits in the Ni-base alloy coating; intercrystalline corrosion also has a dominant role upon the addition of m-CeO2, whereas uniform corrosion occurs in the coating as the size of CeO2 particles is decreased to nanoscale.

  14. Stabilization of nanosized titanium dioxide by cyclodextrin polymers and its photocatalytic effect on the degradation of wastewater pollutants

    Directory of Open Access Journals (Sweden)

    Tamás Zoltán Agócs

    2016-12-01

    Full Text Available Advanced oxidation processes (AOPs are considered highly competitive water treatment technologies for the removal of organic pollutants. Among AOP techniques, photocatalysis has recently been the most widely studied. Our aims were to investigate how the dispersion of nanosized titanium dioxide (nanoTiO2 applied in photodegradation-based procedures can be stabilized with cyclodextrins in order to obtain a new, more efficient photocatalyst for the purification of waters polluted by xenobiotics applying UV irradiation. During our work, on the one hand, we studied the behavior and stability of nanoTiO2 in cyclodextrin solutions. On the other hand, we used various monomer and polymer cyclodextrin derivatives, and assessed the options for nanoTiO2 stabilization in the presence of various salts and tap water on the basis of turbidity tests. The physical stability of nanoTiO2 dispersions is diminished in the presence of the salts found in tap water (and occurring also in surface waters and ground water and they are precipitated immediately. This colloidal instability can be improved by cyclodextrin derivatives. Based on the results of our studies we have selected carboxymethyl β-cyclodextrin polymer (CMBCD-P for stabilization of nanoTiO2 dispersions. The photocatalytic degradation of methylene blue and ibuprofen as model organic pollutants in various media (distilled water, NaCl solution and tap water has been studied using nanoTiO2 as catalyst stabilized by CMBCD-P. CMBCD-P itself showed a catalytic effect on the UV degradation of methylene blue. In addition to enhancing the colloid stability of nanoTiO2 CMBCD-P showed also synergistic effects in catalyzing the photodecomposition process of the dye. On the other hand, ibuprofen as a model pharmaceutical, a pollutant of emerging concern (EP, was protected by CMBCD-P against the photocatalytic degradation showing that inclusion complex formation can result in opposite effects depending on the structure

  15. Nanosized Particles of Silica and Its Derivatives for Applications in Various Branches of Food and Nutrition Sectors

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Kasaai

    2015-01-01

    Full Text Available Nanosized particles of silica and its derivatives have been identified as versatile for a broad range of science, technology, and engineering applications. In this paper, an effort has been made to provide a short review from the available literature information on their applications in various branches of food and nutrition sectors. The information provided in this paper describes various parameters affecting their performances and efficiencies. The properties and applications of nanosilica and its derivatives have been compared with microsilica and bulk-silica for their performances. The use of nanosized particles of silica and its derivatives provides a number of advantages. Their efficiencies and performances are significantly higher than those of the traditional ones.

  16. Recent advances and future perspectives of nanosized zero- valent iron for extraction of heavy elements from metallurgical sludges

    Science.gov (United States)

    Mikhailov, I. Yu; Levina, V. V.; Kolesnikov, E. A.; Chuprunov, K. O.; Gusev, A. A.; Godymchuk, A. Yu; Kuznetsov, D. V.

    2016-01-01

    Advanced oxidation processes with nanosized zero-valent iron have presented great potential in wastewater treatment technology and now experience both increasing popularity and reliable technical improvements. Besides wastewater treatment, there is another promising application for an emerging technology of iron nanoparticles - as Fenton-like catalyst for extraction of valuable elements from poor and secondary raw materials such as metallurgical sludges. In present research, we carried out a set of experiments with emphasis on the physicochemical mechanisms and their relationship to the performance. In particular, we examined complex acidic - hydrogen peroxide leaching of zinc from blast furnace sludge with nanosized zero-valent iron as Fenton-like catalyst. Results of the experiments showed promising potential for subsequent application in extraction of heavy and rare-earth elements.

  17. Recent advances and future perspectives of nanosized zero- valent iron for extraction of heavy elements from metallurgical sludges

    International Nuclear Information System (INIS)

    Mikhailov, I Yu; Levina, V V; Kolesnikov, E A; Chuprunov, K O; Gusev, A A; Godymchuk, A Yu; Kuznetsov, D V

    2016-01-01

    Advanced oxidation processes with nanosized zero-valent iron have presented great potential in wastewater treatment technology and now experience both increasing popularity and reliable technical improvements. Besides wastewater treatment, there is another promising application for an emerging technology of iron nanoparticles - as Fenton-like catalyst for extraction of valuable elements from poor and secondary raw materials such as metallurgical sludges. In present research, we carried out a set of experiments with emphasis on the physicochemical mechanisms and their relationship to the performance. In particular, we examined complex acidic - hydrogen peroxide leaching of zinc from blast furnace sludge with nanosized zero-valent iron as Fenton-like catalyst. Results of the experiments showed promising potential for subsequent application in extraction of heavy and rare-earth elements. (paper)

  18. Molecular dynamics study on nano-sized wiredrawing: possible atomistic process and application to pearlitic steel wire

    Science.gov (United States)

    Saitoh, K.; Yoshida, K.; Oda, K.; Sato, T.; Takuma, M.; Takahashi, Y.

    2018-02-01

    The process of nano-sized wiredrawing is investigated by using molecular dynamics (MD) simulation in this study. The authors have constructed novel computation models of wiredrawing, in which a single wire of just a several nanometers in diameter is smoothly drawn through a perfectly rigid die together with lubrication mechanism and is forced to be shaped into thinner one. Interatomic potentials used in MD simulation is a conventional pairwise type useable for iron-carbon binary system (for pearlitic steel). For MD model of pearlite steel wire, it is recognized that ferrite-cementite interface effectively offers high-speed diffusion path for carbon atoms from cementite side to ferrite side (elementary mechanism of cementite decomposition). As conclusion, we showed by using atomistic simulation that nano-sized wiredrawing process is theoretically quite possible.

  19. Spongelike Nanosized Mn 3 O 4 as a High-Capacity Anode Material for Rechargeable Lithium Batteries

    KAUST Repository

    Gao, Jie

    2011-07-12

    Mn3O4 has been investigated as a high-capacity anode material for rechargeable lithium ion batteries. Spongelike nanosized Mn 3O4 was synthesized by a simple precipitation method and characterized by powder X-ray diffraction, Raman scattering and scanning electron microscopy. Its electrochemical performance, as an anode material, was evaluated by galvanostatic discharge-charge tests. The results indicate that this novel type of nanosized Mn3O4 exhibits a high initial reversible capacity (869 mA h/g) and significantly enhanced first Coulomb efficiency with a stabilized reversible capacity of around 800 mA h/g after over 40 charge/discharge cycles. © 2011 American Chemical Society.

  20. Ductility Enhancement of Molybdenum Phase by Nano-sized Oxide Dispersions

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Bruce

    2008-07-18

    The objective of this research is to understand and to remedy the impurity effects for room-temperature ductility enhancement of molybdenum (Mo) based alloys by the inclusion of nano-sized metal oxide dispersions. This research combines theoretical, computational, and experimental efforts. The results will help to formulate systematic strategies in searching for better composed Mo-based alloys with optimal mechanical properties. For this project, majority of the research effort was directed to atomistic modeling to identify the mechanisms responsible for the oxygen embrittling and ductility enhancement based on fundamental electronic structure analysis. Through first principles molecular dynamics simulations, it was found that the embrittling impurity species were attracted to the metal oxide interface, consistent with previous experiments. Further investigation on the electronic structures reveals that the presence of embrittling species degrades the quality of the metallic chemical bonds in the hosting matrix in a number of ways, the latter providing the source of ductility. For example, the spatial flexibility of the bonds is reduced, and localization of the impurity states occurs to pin the dislocation flow. Rice’s criterion has been invoked to explain the connections of electronic structure and mechanical properties. It was also found that when impurity species become attracted to the metal oxide interface, some of the detrimental effects are alleviated, thus explaining the observed ductility enhancement effects. These understandings help to develop predictive capabilities to facilitate the design and optimization of Mo and other high temperature alloys (e.g. ODS alloys) for fossil energy materials applications. Based on the theoretical and computational studies, the experimental work includes the preparation of Mo powders mixed with candidate nano-sized metal oxides, which were then vacuum hot-pressed to make the Mo alloys. Several powder mixing methods

  1. Cationic amylose-encapsulated bovine hemoglobin as a nanosized oxygen carrier.

    Science.gov (United States)

    Gao, Wei; Sha, Baoyong; Zou, Wei; Liang, Xuan; Meng, Xiangzhong; Xu, Hao; Tang, Jun; Wu, Daocheng; Xu, Lixian; Zhang, Hui

    2011-12-01

    Nanosized hemoglobin-based oxygen carriers are one of the most promising blood substitutes. In the present study, a comprehensive strategy for the preparation of nanosized cationic amylose-encapsulated hemoglobins (NCAHbs) was developed. First, cationic amylase (CA) was synthesized from amylose and quaternary ammonium salt by an etherification reaction. The structure of CA was characterized using Fourier transform infrared spectrophotometry (FTIR) and proton nuclear magnetic resonance spectrophotometry ((1)H NMR). The degree of substitution and the zeta potential were also measured. Then, the NCAHbs were prepared by electrostatic adhesion, reverse micelles and cross-linking. The UV-visible spectrophotometer was used to measure the entrapment efficiency (EE%) and drug loading efficiency (DL%) of the NCAHbs. Transmission electron microscopy and Malvern Nano-zs 90 analyzer were used to observe the size distribution and morphology of particles. Chemical structure was determined from the FTIR spectrum. A Hemox analyzer was used to measure the P(50) and Hill coefficients. A lethal hemorrhagic shock model in rats was used to evaluate the therapeutic effect of the NCAHbs. The results showed that the combined methods improved the size, stability, EE%, DL%, and oxygen-carrying capacity of the NCAHbs. The average diameter of the NCAHbs was 92.53 ± 3.64 nm, with a narrow polydispersity index of 0.027. The EE% was 80.05% ± 1.56% and DL% was 61.55% ± 1.41%. The P(50) and Hill coefficient were equal to 28.96 ± 1.33 mmHg and 2.55 ± 0.22, respectively. The size of NCAHbs remained below 200 nm for six days in PBS solution. The NCAHbs could effectively prevent lung injury from progressing to lethal hemorrhagic shock because they acted as both a volume expander and an oxygen carrier. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Ecotoxicological studies of micro- and nanosized barium titanate on aquatic photosynthetic microorganisms.

    Science.gov (United States)

    Polonini, Hudson C; Brandão, Humberto M; Raposo, Nádia R B; Mouton, Ludovic; Yéprémian, Claude; Couté, Alain; Brayner, Roberta

    2014-09-01

    The interaction between live organisms and micro- or nanosized materials has become a current focus in toxicology. As nanosized barium titanate has gained momentum lately in the medical field, the aims of the present work are: (i) to assess BT toxicity and its mechanisms on the aquatic environment, using two photosynthetic organisms (Anabaena flos-aquae, a colonial cyanobacteria, and Euglena gracilis, a flagellated euglenoid); (ii) to study and correlate the physicochemical properties of BT with its toxic profile; (iii) to compare the BT behavior (and Ba(2+) released ions) and the toxic profile in synthetic (Bold's Basal, BB, or Mineral Medium, MM) and natural culture media (Seine River Water, SRW); and (iv) to address whether size (micro, BT MP, or nano, BT NP) is an issue in BT particles toxicity. Responses such as growth inhibition, cell viability, superoxide dismutase (SOD) activity, adenosine-5-triphosphate (ATP) content and photosynthetic efficiency were evaluated. The main conclusions are: (i) BT have statistically significant toxic effects on E. gracilis growth and viability even in small concentrations (1μgmL(-1)), for both media and since the first 24 h; on the contrary of on A. flos-aquae, to whom the effects were noticeable only for the higher concentrations (after 96 h: ≥75 μg mL(-1) for BT NP and =100 μg mL(-1) for BT MP, in BB; and ≥75 μg mL(-1) for both materials in SRW), in spite of the viability being affected in all concentrations; (ii) the BT behaviors in synthetic and natural culture media were slightly different, being the toxic effects more pronounced when grown in SRW - in this case, a worse physiological state of the organisms in SRW can occur and account for the lower resistance, probably linked to a paucity of nutrients or even a synergistic effect with a contaminant from the river; and (iii) the effects seem to be mediated by induced stress without a direct contact in A. flos-aquae and by direct endocytosis in E. gracilis, but in

  3. Development and characterization of dilutable self-microemulsifying premicroemulsion systems (SMEPMS as templates for preparation of nanosized particulates

    Directory of Open Access Journals (Sweden)

    Lin SF

    2013-09-01

    Full Text Available Shen-Fu Lin,1 Ying-Chen Chen,2 Hsiu-O Ho,2 Wei-Yu Huang,2 Ming-Thau Sheu,2,3 Der-Zen Liu1,4 1Graduate Institute of Biomedical Materials and Tissue Engineering, College of Oral Medicine, 2School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei, Taiwan; 3Clinical Research Center and Traditional Herbal Medicine Research Center, Taipei Medical University Hospital, Taipei, Taiwan; 4Center for General Education, Hsuan Chuang University, Hsinchu, Taiwan Abstract: The utilization of self-microemulsifying premicroemulsion systems (SMEPMS as templates for preparing poorly water-soluble compounds in the nanosized range represents a promising strategy. Fenofibrate was formulated with n-butyl L-lactate, Tween 80, and a number of cosurfactants (ethanol, 1-propanol, and PEG 600, diluted with the water phase (either water or saccharide solution and then subjected to a freeze-drying (FD process to obtain SMEPMS nanosized particulates. Results demonstrated that the particle size after resuspension of these FD SMEPMS nanosized particulates in water was too large, so the addition of saccharide solutions (lactose, mannitol, glucose, sucrose, and trehalose as the solid carrier to prevent particles from aggregating seemed to be necessary and workable due to steric hindrance and repulsion. However, instability of these resuspended FD nanosized particulates after 30–90 minutes still occurred, and the addition of 0.5% sodium lauryl sulfate in the resuspending medium was able to retard the aggregation and maintain the particle size within the nano-range. Evaluation by scanning electron microscopy and X-ray powder diffraction also confirmed the results. It was concluded that using an SMEPMS formulation with PEG 600 as the cosurfactant, and in the presence of a suitable saccharide as an anticaking agent and FD process were able to produce fenofibrate nanoparticles. Keywords: fenofibrate, saccharides, freeze-drying, nanoparticles

  4. Semiconductor adsorption sensors based on nanosized Pt/SnO2 materials and their sensitivity to methane

    Science.gov (United States)

    Fedorenko, G. V.; Oleksenko, L. P.; Maksymovych, N. P.; Matushko, I. P.

    2015-12-01

    The effect of platinum additives on the sensitivity of sensors based on nanosized tin oxide to methane is investigated. It is shown that addition of Pt increases a sensor's sensitivity to CH4. It is found that the dependences of electrical resistance and sensor sensitivity on the concentration of the impregnating solutions of H2[PtCl6] are extremal, which is explained from the point of view of heterogeneous catalysis concepts of the functioning of semiconductor adsorption sensors.

  5. WC-Co COATINGS AND SINTERS MODIFIED WITH NANO-SIZED TiC MICROSTRUCTURE – QUANTITATIVE EVALUATION

    OpenAIRE

    Hanna Myalska; Bartłomiej Dybowski; Grzegorz Moskal

    2017-01-01

    The different concepts of WC-Co thermally sprayed coatings improvement may be considered and the application of nanoparticles, as the mechanical strengthening addition, is one of them. Nanostructured WC-Co coatings are characterized by higher hardness than the coatings formed from micrometric WC grains; whereas coatings with bimodal distribution of particles reveal greater wear resistance than the coatings obtained exclusively from nano-sized powders. Mixed effect of the matrix reinforcement ...

  6. A high gradient and strength bioseparator with nano-sized immunomagnetic particles for specific separation and efficient concentration of E. coli O157:H7

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Jianhan, E-mail: jianhan@cau.edu.cn [Ministry of Agriculture Key Laboratory of Agricultural Information Acquisition Technology (Beijing), 17 East Tsinghua Road, China Agricultural University, Mailbox 125, Beijing 100083 (China); Li, Min [College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058 (China); Li, Yanbin [College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058 (China); Department of Biological and Agricultural Engineering, University of Arkansas, Fayetteville, AR 72701 (United States); Chen, Qi [Modern Precision Agriculture System Integration Research Key Laboratory of Ministry of Education, China Agricultural University, Beijing 100083 (China)

    2015-03-15

    Sample pretreatment is a key to rapid screening of pathogens for prevention and control of foodborne diseases. Magnetic immunoseparation is a specific method based on antibody–antigen reaction to capture the target bacteria and concentrate them in a smaller-volume buffer. The use of nano-sized magnetic particles could improve the separation efficiency of bacteria but require much higher gradient and strength magnetic field. In this study, a strong magnetic bioseparator with a mean field strength of 1.35 T and a mean gradient of 90 T/m was developed with the use of the 30 nm and 180 nm magnetic particles to specifically separate and efficiently concentrate foodborne bacterial pathogens using Escherichia coli O157:H7 as a model bacterium. The polyclonal antibodies against E. coli were evaluated using Dot ELISA analysis for their good affinity with the target bacteria and then used to modify the surface of the magnetic nanoparticles by 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC·HCl) method and streptavidin-biotin binding. The magnetic particle concentrations were optimized to be 40 µg/ml and 100 µg/ml for the 30 nm and 180 nm particles, respectively, the immunoreaction time was optimized to be 45 min for both sizes of particles, and the separation times were optimized to be 60 min and 2 min for the 30 nm and 180 nm particles, respectively. The total magnetic separation time was 2 h and 1 h for the 30 nm and 180 nm particles, respectively. The experimental results demonstrated that the bioseparator with the use of either 30 nm or 180 nm immunomagnetic particles could achieve a separation efficiency of >90% for E. coli O157:H7 at the concentrations ranging from 10{sup 2} to 10{sup 5} cfu/ml. No obvious interferences from non-target foodborne pathogens, such as SalmonellaTyphimurium and Listeria innocua, were found. For overall consideration of the consuming time, the cost, and the separation efficiency, the 180 nm magnetic particles are

  7. Condensation-Enhanced Self-Assembly as a Route to High Surface Area alpha-Aluminas

    NARCIS (Netherlands)

    Perez, Lidia Lopez; Zarubina, Valeriya; Heeres, Hero Jan; Melian-Cabrera, Ignacio

    2013-01-01

    High surface area nanosized alpha-alumina has been obtained by thermally treating a sol-gel-derived mesophase at 1200 degrees C; the mesophase was synthesized by a sol-gel route involving evaporation induced self-assembly (EISA) of a hydrolyzed gel from Al-tri-sec-butoxide in s-BuOH in the presence

  8. Nanosized carbon black combined with Ni2O3 as "universal" catalysts for synergistically catalyzing carbonization of polyolefin wastes to synthesize carbon nanotubes and application for supercapacitors.

    Science.gov (United States)

    Wen, Xin; Chen, Xuecheng; Tian, Nana; Gong, Jiang; Liu, Jie; Rümmeli, Mark H; Chu, Paul K; Mijiwska, Ewa; Tang, Tao

    2014-04-01

    The catalytic carbonization of polyolefin materials to synthesize carbon nanotubes (CNTs) is a promising strategy for the processing and recycling of plastic wastes, but this approach is generally limited due to the selectivity of catalysts and the difficulties in separating the polyolefin mixture. In this study, the influence of nanosized carbon black (CB) and Ni2O3 as a novel combined catalyst system on catalyzing carbonization of polypropylene (PP), polyethylene (PE), polystyrene (PS) and their blends was investigated. We showed that this combination was efficient to promote the carbonization of these polymers to produce CNTs with high yields and of good quality. Catalytic pyrolysis and model carbonization experiments indicated that the carbonization mechanism was attributed to the synergistic effect of the combined catalysts rendered by CB and Ni2O3: CB catalyzed the degradation of PP, PE, and PS to selectively produce more aromatic compounds, which were subsequently dehydrogenated and reassembled into CNTs via the catalytic action of CB together with Ni particles. Moreover, the performance of the synthesized CNTs as the electrode of supercapacitor was investigated. The supercapacitor displayed a high specific capacitance as compared to supercapacitors using commercial CNTs and CB. This difference was attributed to the relatively larger specific surface areas of our synthetic CNTs and their more oxygen-containing groups.

  9. Evaluation of heavy metals in hazardous automobile shredder residue thermal residue and immobilization with novel nano-size calcium dispersed reagent.

    Science.gov (United States)

    Lee, Chi-Hyeon; Truc, Nguyen Thi Thanh; Lee, Byeong-Kyu; Mitoma, Yoshiharu; Mallampati, Srinivasa Reddy

    2015-10-15

    This study was conducted to synthesize and apply a nano-size calcium dispersed reagent as an immobilization material for heavy metal-contaminated automobile shredder residues (ASR) dust/thermal residues in dry condition. Simple mixing with a nanometallic Ca/CaO/PO4 dispersion mixture immobilized 95-100% of heavy metals in ASR dust/thermal residues (including bottom ash, cavity ash, boiler and bag filter ash). The quantity of heavy metals leached from thermal residues after treatment by nanometallic Ca/CaO/PO4 was lower than the Korean standard regulatory limit for hazardous waste landfills. The morphology and elemental composition of the nanometallic Ca/CaO-treated ASR residue were characterized by field emission scanning election microscopy combined with electron dispersive spectroscopy (FE-SEM/EDS). The results indicated that the amounts of heavy metals detectable on the ASR thermal residue surface decreased and the Ca/PO4 mass percent increased. X-ray diffraction (XRD) pattern analysis indicated that the main fraction of enclosed/bound materials on ASR residue included Ca/PO4- associated crystalline complexes, and that immobile Ca/PO4 salts remarkably inhibited the desorption of heavy metals from ASR residues. These results support the potential use of nanometallic Ca/CaO/PO4 as a simple, suitable and highly efficient material for the gentle immobilization of heavy metals in hazardous ASR thermal residue in dry condition. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Adsorption and Desorption Characteristics of Cd2+ and Pb2+ by Micro and Nano-sized Biogenic CaCO3

    Directory of Open Access Journals (Sweden)

    Renlu Liu

    2018-01-01

    Full Text Available The purpose of this study was to elucidate the characteristics and mechanisms of adsorption and desorption for heavy metals by micro and nano-sized biogenic CaCO3 induced by Bacillus subtilis, and the pH effect on adsorption was investigated. The results showed that the adsorption characteristics of Cd2+ and Pb2+ are well described by the Langmuir adsorption isothermal equation, and the maximum adsorption amounts for Cd2+ and Pb2+ were 94.340 and 416.667 mg/g, respectively. The maximum removal efficiencies were 97% for Cd2+, 100% for Pb2+, and the desorption rate was smaller than 3%. Further experiments revealed that the biogenic CaCO3 could maintain its high adsorption capability for heavy metals within wide pH ranges (3–8. The FTIR and XRD results showed that, after the biogenic CaCO3 adsorbed Cd2+ or Pb2+, it did not produce a new phase, which indicated that biogenic CaCO3 and heavy metal ions were governed by a physical adsorption process, and the high adsorptive capacity of biogenic CaCO3 for Cd2+ and Pb2+ were mainly attributed to its large total specific surface area. The findings could improve the state of knowledge about biogenic CaCO3 formation in the environment and its potential roles in the biogeochemical cycles of heavy metals.

  11. Design and development of a new generation of UV-visible-light-driven nanosized codoped titanium dioxide photocatalysts and biocides/sporocides, and environmental applications

    Science.gov (United States)

    Hamal, Dambar B.

    For solar environmental remediation, a new generation of nanosized (activities for acetaldehyde degradation under visible light (wavelength > 420 nm). It was concluded that high visible-light-activities for acetaldehyde degradation over codoped titanium dioxide were attributed to an interplay of anatase crystallinity, high-surface area, reduced band-gap (activities of metal doped/codoped photocatalysts under UV light (wavelength pollutants. Indium demonstrated beneficial effects in both textural and photocatalytic properties. Gallium and indium codoped titanium dioxide photocatalysts displayed even better performance in the CO oxidation reaction under UV light. Notably, titanium dioxide codoped with Ga, In, and Pt, exhibited unique photoactivities for the CO oxidation under both UV and visible light irradiation, indicating that this system could have promise for the water-gas shift reaction for hydrogen production. Silver-based nanostructured titanium dioxide samples were developed for killing human pathogens (Escherichia coli cells and Bacillus subtilis spores). Biocidal tests revealed that silver, carbon, and sulfur codoped titanium dioxide nanoparticles (antimicrobial actions on both E. coli (logarithmic kill > 8) and B. subtilis spores (logarithmic kill > 5) for 30 minute exposures in dark conditions compared with Degussa P25. It was believed that the carbon and sulfur codoped titanium dioxide support and Ag species acted synergistically during deactivation of both E. coli and B. subtilis spores. Thus, titanium dioxide codoped with silver, carbon, sulfur can serve as a multifunctional generic biocide and a visible-light-active photocatalyst.

  12. Adsorption and Desorption Characteristics of Cd2+ and Pb2+ by Micro and Nano-sized Biogenic CaCO3

    Science.gov (United States)

    Liu, Renlu; Guan, Yong; Chen, Liang; Lian, Bin

    2018-01-01

    The purpose of this study was to elucidate the characteristics and mechanisms of adsorption and desorption for heavy metals by micro and nano-sized biogenic CaCO3 induced by Bacillus subtilis, and the pH effect on adsorption was investigated. The results showed that the adsorption characteristics of Cd2+ and Pb2+ are well described by the Langmuir adsorption isothermal equation, and the maximum adsorption amounts for Cd2+ and Pb2+ were 94.340 and 416.667 mg/g, respectively. The maximum removal efficiencies were 97% for Cd2+, 100% for Pb2+, and the desorption rate was smaller than 3%. Further experiments revealed that the biogenic CaCO3 could maintain its high adsorption capability for heavy metals within wide pH ranges (3–8). The FTIR and XRD results showed that, after the biogenic CaCO3 adsorbed Cd2+ or Pb2+, it did not produce a new phase, which indicated that biogenic CaCO3 and heavy metal ions were governed by a physical adsorption process, and the high adsorptive capacity of biogenic CaCO3 for Cd2+ and Pb2+ were mainly attributed to its large total specific surface area. The findings could improve the state of knowledge about biogenic CaCO3 formation in the environment and its potential roles in the biogeochemical cycles of heavy metals. PMID:29434577

  13. Compound Method to Disperse CaCO3 Nanoparticles to Nano-Size in Water.

    Science.gov (United States)

    Gu, Sui; Cai, Jihua; Wang, Jijun; Yuan, Ye; Chang, Dewu; Chikhotkin, Viktor F

    2015-12-01

    The invalidation of CaCO3 nanoparticles (nCaCO3) is often caused by the fact of agglomeration and inhomogeneous dispersion which limits its application into water-based drilling muds for low permeability reservoirs such as coalbed methane reservoir and shale gas/oil reservoir. Effective methods to disperse nCaCO3 to nano-size (≤ 100 nm) in water have seldom been reported. Here we developed a compound method containing mechanical stirring, ultrasonic treatment, the use of surfactant and stabilizer to disperse nCaCO3 in water. It comprises the steps adding 2% nCaCO3, 1% sodium dodecyl sulfonate (SDS), 2% cetyltrimethyl ammonium bromide (CTAB), 2% OP-10, 3% to 4% biopolymer (XC) in water successively, stirring it at a shear rate of 6000 to 8000 r/min for 15 minutes and treating it with ultrasonic at a frequency of 28 KHz for 30 to 40 minutes. The dispersed nCaCO3 was characterized with scanning electron microscope (SEM), transmission electron microscope (TEM) and particle size distribution (PSD) tests. We found that nCaCO3 could be dispersed to below 100 nm in water and the medium value of nCaCO3 was below 50 nm. This method paved the way for the utilization of nCaCO3 in drilling fluid and completion fluid for low permeability reservoirs such as coal seams and shale gas/oil formations.

  14. Insights into the electrochemical activity of nanosized {alpha}-LiFeO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Morales, J.; Santos-Pena, J.; Trocoli, R. [Departamento de Quimica Inorganica e Ingenieria Quimica, Edificio Marie Curie, Campus de Rabanales, Universidad de Cordoba, Cordoba 14071 (Spain); Franger, S. [Laboratoire de Physico-Chimie de l' Etat Solide, ICMMO, Universite Paris XI, Orsay 91405 (France); Rodriguez-Castellon, E. [Departamento de Quimica Inorganica, Cristalografia y Mineralogia, Campus de Teatinos, Universidad de Malaga, Malaga 29071 (Spain)

    2008-09-20

    In recent work [J. Morales, J. Santos-Pena, Electrochem. Commun. 9 (2007) 2116], we prepared nanosized {alpha}-LiFeO{sub 2} with increased electrochemical activity in lithium cells relative to various lithium ferrite polymorphs. In this work, we studied the previous electrodes in different charge states in order to obtain a more accurate picture of the phenomena occurring during cycling. Exsitu X-ray photoelectron spectroscopy (XPS) measurements confirmed the oxidation/reduction of iron atoms during the charge/discharge process. The electrochemical impedance spectroscopy results suggested that the electrolyte is not oxidised during the first charge, but rather than a solid electrolyte interface is formed after one cycle. Also, thermal tests revealed that Fe(IV) present in the electrodes reacted with the electrolyte to form oxidised carbon species. Finally, {alpha}-LiFeO{sub 2} was tested as a positive electrode material in a lithium battery under different regimes. Stabilised capacities up to 150 mAh g{sup -1} were obtained under a C/4 regime. This lithium ferrite is therefore an attractive alternative to LiCoO{sub 2}. (author)

  15. Photoluminescent nano-sized ternary and quaternary complexes of thorium(IV)

    International Nuclear Information System (INIS)

    Baranwal, B.P.; Jain, A.K.; Varma, A.; Singh, A.K.; Fatma, T.

    2011-01-01

    Some ternary and quaternary complexes of thorium(IV) with the general formula [Th(OOCCH 3 ) 2-n (SB) n (OOCC 15 H 31 ) 2 ] (HSB=Schiff bases and n=1 or 2) have been synthesized by the stepwise substitutions of acetate ions from thorium(IV) acetate, first with straight chain carboxylic acid and then with Schiff bases. The complexes are characterized by elemental analyses, spectral (electronic, infrared, 1 H NMR, FAB mass, photoluminescence and powder XRD) and TEM studies. Conductance measurements indicated non-conducting behaviour of the complexes. Structural parameters from powder XRD data for complexes 5 and 6 which indicate poorly crystalline nano-sized triclinic particles. Electronic absorption spectra of the complexes showed π → π * and n → π * charge transfer transitions. All complexes displayed fluorescence and a correlation was sought between luminescence spectra of complexes in solution at room temperature. On the basis of physico-chemical studies, coordination number 8 was assigned for thorium(IV) in the complexes. The morphology and microstructure of the complexes were examined with transmission electron microscopy (TEM) and the selected area electron diffraction (SAED). (orig.)

  16. Amplified CPEs enhancement of chorioamnion membrane mass transport by encapsulation in nano-sized PLGA particles.

    Science.gov (United States)

    Azagury, Aharon; Amar-Lewis, Eliz; Appel, Reut; Hallak, Mordechai; Kost, Joseph

    2017-08-01

    Chemical penetration enhancers (CPEs) have long been used for mass transport enhancement across membranes. Many CPEs are used in a solution or gel and could be a solvent. The use of CPEs is mainly limited due to their toxicity/irritation levels. This study presents the evaluation of encapsulated CPEs in nano-sized polymeric particles on the chorioamnion (CA) membrane mass transport. CPEs' mass encapsulated in nanoparticles was decreased by 10,000-fold. Interestingly, this approach resulted in a 6-fold increase in mass transport across the CA. This approach may also be used with other CPEs' base applications necessitating lower CPE concentration. Applying Ultrasound (US) has shown to increase the release rate of and also the mass transport across the CA membrane. It is proposed that encapsulated CPEs penetrate into the CA membrane thus prolonging their exposure, possibly extending their penetration into the CA membrane, while insonation also deepens their penetration into the CA membrane. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Nanosized TiO2-induced reproductive system dysfunction and its mechanism in female mice.

    Directory of Open Access Journals (Sweden)

    Xiaoyang Zhao

    Full Text Available Recent studies have demonstrated nanosized titanium dioxide (nano-TiO2-induced fertility reduction and ovary injury in animals. To better understand how nano-TiO2 act in mice, female mice were exposed to 2.5, 5, and 10 mg/kg nano-TiO2 by intragastric administration for 90 consecutive days; the ovary injuries, fertility, hormone levels, and inflammation-related or follicular atresia-related cytokine expression were investigated. The results showed that nano-TiO2 was deposited in the ovary, resulting in significant reduction of body weight, relative weight of ovary and fertility, alterations of hematological and serum parameters and sex hormone levels, atretic follicle increases, inflammation, and necrosis. Furthermore, nano-TiO2 exposure resulted in marked increases of insulin-like growth factor-binding protein 2, epidermal growth factor, tumor necrosis factor-α, tissue plasminogen activator, interleukin-1β, interleukin -6, Fas, and FasL expression, and significant decreases of insulin-like growth factor-1, luteinizing hormone receptor, inhibin α, and growth differentiation factor 9 expression in mouse ovary. These findings implied that fertility reduction and ovary injury of mice following exposure to nano-TiO2 may be associated with alteration of inflammation-related or follicular atresia-related cytokine expressions, and humans should take great caution when handling nano-TiO2.

  18. Nanosized-Particle Dispersion-Strengthened Al Matrix Composites Fabricated by the Double Mechanical Alloying Process.

    Science.gov (United States)

    Kim, Chungseok

    2018-03-01

    The objective of this study was to fabricate an Al metal matrix composite strengthened by nanosized Al3Ti particles via double mechanical alloying process. Several Al-xTi alloys were fabricated, including Al-12%Ti, Al-15%Ti, and Al-12%Ti-1%Y2O3. The lattice parameter of as-milled state was calculated to be 4.0485 Å; after a milling time of 540 min, it was 4.0401 Å. This decrease was induced by Ti solutionizing into the Al matrix. The equivalent size of a coarse Al3Ti particle was 200-500 nm after the heat treatment; however, the particles were uniformly distributed and were refined through the MA2 process. The particle size of a Al3Ti phase was 30 nm or less, and the particles were uniformly distributed. These particles remained in a fine state in the matrix without growth and coarsening, even after the hot extrusion process. The microstructure of hot extruded alloys consisted of a uniform distribution of Al3Ti particles and other dispersoids in the Al matrix.

  19. A Review of In Vitro Drug Release Test Methods for Nano-Sized Dosage Forms

    Directory of Open Access Journals (Sweden)

    Susan D’Souza

    2014-01-01

    Full Text Available This review summarizes the methods used to study real-time (37°C drug release from nanoparticulate drug delivery systems and establish an IVIVC. Since no compendial standards exist, drug release is currently assessed using a variety of methods including sample and separate (SS, continuous flow (CF, dialysis membrane (DM methods, and a combination thereof, as well as novel techniques like voltametry and turbidimetry. This review describes the principle of each method along with their advantages and disadvantages, including challenges with set-up and sampling. The SS method allows direct measurement of drug release with simple set-up requirements, but sampling is cumbersome. With the CF method, sampling is straightforward but the set-up is time consuming. Set-up as well as sampling is easier with the DM, but it may not be suitable for drugs that bind to the membrane. Novel methods offer the possibility of real-time drug release measurement but may be restricted to certain types of drugs. Of these methods, Level A IVIVCs have been obtained with dialysis, alone or in combination with the sample and separate technique. Future efforts should focus on developing mathematical models that describe drug release mechanisms as well as facilitate formulation development of nano-sized dosage forms.

  20. Nanosized tungsten carbide synthesized by a novel route at low temperature for high performance electrocatalysis

    Science.gov (United States)

    Yan, Zaoxue; Cai, Mei; Shen, Pei Kang

    2013-04-01

    Tungsten carbide (WC) is a widely used engineering material which is usually prepared at high temperature. A new mechanism for synthesizing nanoscaled WC at ultralow temperature has been discovered. This discovery opens a novel route to synthesize valuable WC and other carbides at a cost-efficient way. The novel formation mechanism is based on an ion-exchange resin as carbon source to locally anchor the W and Fe species. As an intermediate, FeWO4 can be formed at lower temperature, which can be directly converted into WC along with the carbonization of resin. The size of WC can be less than 2 nm. The catalyst made with Pt nanoparticles supported on nanosized WC-GC (WC-graphitized carbon) shows enhanced electrocatalytic activity for oxygen reduction reaction. The result also indicates that the Pt nanoparticles deposited on WC-GC are dominated by Pt (111) plane and shows a mass activity of 257.7 mA mg-1Pt@0.9 V.

  1. Overproduction, purification, and characterization of nanosized polyphosphate bodies from Synechococcus sp. PCC 7002.

    Science.gov (United States)

    Gao, Fengzheng; Wu, Haohao; Zeng, Mingyong; Huang, Min; Feng, Guangxin

    2018-02-20

    Inorganic polyphosphate bodies (PPB) have recently been linked to a variety of functions in mammalian cells. To improve the yield of PPB from Synechococcus sp. PCC 7002 and characterize its form, in this study, a recombinant plasmid containing a polyphosphate kinase (ppk) gene was generated and transformed into Synechococcus sp. PCC 7002. PPB separated by Sephadex G-100 was characterized and added to polarized human intestinal epithelial (Caco-2) cells, and the absorption effect was assessed. The ppk gene was stably expressed by induction with 1 μM nickel, and the resulting PPB yield from Synechococcus sp. PCC 7002 cells increased by 89.66%. Transmission electron microscopy and dynamic light scattering analyses showed that PPB from these cells were nanosized, ranging from a few to approximately 100 nanometres in diameter. PPB can be taken up by Caco-2 cells and are mainly distributed around lipid droplets. We determined that PPB can be overproduced in Synechococcus sp. PCC 7002 and that the resulting PPB were well absorbed by Caco-2 cells. Microalgae provide a promising "cell factory" for PPB production.

  2. Production of drug nanosuspensions: effect of drug physical properties on nanosizing efficiency.

    Science.gov (United States)

    Liu, Tao; Müller, Rainer H; Möschwitzer, Jan P

    2018-02-01

    Drug nanosuspension is one of the established methods to improve the bioavailability of poorly soluble drugs. Drug physical properties aspect (morphology, solid state, starting size et al) is a critical parameter determining the production efficiency. Some drug modification approaches such as spray-drying were proved to improve the millability of drug powders. However, the mechanism behind those improved performances is unclear. This study is to systematically investigate the influence of those physical properties. Five different APIs (active pharmaceutical ingredients) with different millabilities, i.e. resveratrol, hesperetin, glibenclamide, rutin, and quercetin, were processed by standard high pressure homogenization (HPH), wet bead milling (WBM), and a combinative method of spray-drying and HPH. Smaller starting sizes of certain APIs could accelerate the particle size reduction velocity during both HPH and WBM processes. Spherical particles were observed for almost all spray-dried powders (except spray-dried hesperetin) after spray-drying. The crystallinity of some spray-dried samples such as rutin and glibenclamide became much lower than their corresponding unmodified powders. Almost all spray-dried drug powders after HPH processes could lead to smaller nanocrystal particle size than unmodified APIs. The modified microstructure instead of solid state after spray-drying explained the potential reason for improved nanosizing efficiency. In addition, the contribution of starting size on the production efficiency was also critical according to both HPH and WBM results.

  3. Influence of Lithium on Nanosized Films of Fe2O3

    Directory of Open Access Journals (Sweden)

    A. Turković

    2011-01-01

    Full Text Available We have investigated nanosized thin films of α-Fe2O3 (hematite and α-Fe2O3 with addition of Li, by the impedance spectroscopy (IS, the Raman spectroscopy, scanning electron microscopy (SEM, and X-ray diffraction (XRD. Combining all of these methods, and earlier obtained thermally stimulated currents (TSC on the same samples, the dependence of structural and electrical properties upon percentage of Li added into the matrix of these metal-oxide films was found. The comparison of IS, Raman, SEM, XRD, and TSC results reveals the increase of the size of nanoparticles upon inducing 1% of Li in Fe2O3 matrix followed by the decrease of the size of nanoparticles in the case of samples with 10% Li, as well as the decrease (increase of conductivity, respectively. These changes are explained by the structural and morphological changes caused by the impact of Li+ ions in the charge transfers. This material is suitable for application in the galvanic cell of second generation that could be used as solar-cells backup.

  4. Nanosize effect of clay mineral nanoparticles on the drug diffusion processes in polyurethane nanocomposite hydrogels

    Science.gov (United States)

    Miotke, M.; Strankowska, J.; Kwela, J.; Strankowski, M.; Piszczyk, Ł.; Józefowicz, M.; Gazda, M.

    2017-09-01

    Studies of swelling and release of naproxen sodium (NAP) solution by polyurethane nanocomposite hydrogels containing Cloisite® 30B (organically modified montmorillonite (OMMT)) have been performed. Polyurethane nanocomposite hydrogels are hybrid, nontoxic biomaterials with unique swelling and release properties in comparison with unmodified hydrogels. These features enable to use nanocomposite hydrogels as a modern wound dressing. The presence of nanoparticles significantly improves the swelling. On the other hand, their presence hinders drug diffusion from polymer matrix and consequently causes delay of the drug release. The kinetics of swelling and release were carefully analyzed using the Korsmeyer-Peppas and the modified Hopfenberg models. The models were fitted to precise experimental data allowing accurate quantitative and qualitative analysis. We observed that 0.5% admixture of nanoparticles (Cloisite® 30B) is the best concentration for hydrogel swelling properties. The release process was studied using fluorescence excitation spectra of NAP. Furthermore, we studied swelling hysteresis; polymer chains have not been destroyed after the swelling and part of swelled solution with active substances which remained absorbed in the polymer matrix after the drying process. We have found that the amount of solution with NAP remained in the nanocomposite matrix is greater than in pure hydrogel, as a consequence of NAP-OMMT interactions (nanosize effect).

  5. Vibrational contribution to the thermodynamics of nanosized precipitates: vacancy-copper clusters in bcc-Fe

    International Nuclear Information System (INIS)

    Talati, Mina; Posselt, Matthias; Al-Motasem, Ahmed; Bergner, Frank; Bonny, Giovanni

    2012-01-01

    The effects of lattice vibration on the thermodynamics of nanosized coherent clusters in bcc-Fe consisting of vacancies and/or copper are investigated within the harmonic approximation. A combination of on-lattice simulated annealing based on Metropolis Monte Carlo simulations and off-lattice relaxation by molecular dynamics is applied to obtain the most stable cluster configurations at T = 0 K. The most recent interatomic potential built within the framework of the embedded-atom method for the Fe-Cu system is used. The total free energy of pure bcc-Fe and fcc-Cu as well as the total formation free energy and the total binding free energy of the vacancy-copper clusters are determined for finite temperatures. Our results are compared with the available data from previous investigations performed using many-body interatomic potentials and first-principles methods. For further applications in rate theory and object kinetic Monte Carlo simulations, the vibrational effects evaluated in the present study are included in the previously developed analytical fitting formulae. (paper)

  6. Molecular Mechanisms of Nanosized Titanium Dioxide–Induced Pulmonary Injury in Mice

    Science.gov (United States)

    Sang, Xuezi; Cui, Yaling; Wang, Xiaochun; Gui, Suxin; Tan, Danlin; Zhu, Min; Zhao, Xiaoyang; Sheng, Lei; Wang, Ling; Hong, Fashui; Tang, Meng

    2013-01-01

    The pulmonary damage induced by nanosized titanium dioxide (nano-TiO2) is of great concern, but the mechanism of how this damage may be incurred has yet to be elucidated. Here, we examined how multiple genes may be affected by nano-TiO2 exposure to contribute to the observed damage. The results suggest that long-term exposure to nano-TiO2 led to significant increases in inflammatory cells, and levels of lactate dehydrogenase, alkaline phosphate, and total protein, and promoted production of reactive oxygen species and peroxidation of lipid, protein and DNA in mouse lung tissue. We also observed nano-TiO2 deposition in lung tissue via light and confocal Raman microscopy, which in turn led to severe pulmonary inflammation and pneumonocytic apoptosis in mice. Specifically, microarray analysis showed significant alterations in the expression of 847 genes in the nano-TiO2-exposed lung tissues. Of 521 genes with known functions, 361 were up-regulated and 160 down-regulated, which were associated with the immune/inflammatory responses, apoptosis, oxidative stress, the cell cycle, stress responses, cell proliferation, the cytoskeleton, signal transduction, and metabolic processes. Therefore, the application of nano-TiO2 should be carried out cautiously, especially in humans. PMID:23409001

  7. Preparation of soft-agglomerated nano-sized ceramic powders by sol-gel combustion process

    International Nuclear Information System (INIS)

    Feng, Q.; Ma, X.H.; Yan, Q.Z.; Ge, C.C.

    2009-01-01

    The soft-agglomerated Gd 2 BaCuO 5 (Gd211) nano-powders were synthesized by sol-gel combustion process with binary ligand and the special pretreatment on gel. The mechanism of the formation of weakly agglomerated structure was studied in detail. The results showed that network structure in gelation process was found to be a decisive factor for preventing agglomeration of colloidal particles. The removal of free water, coordinated water, and most of hydroxyl groups during pretreatment further inhibited the formation of hydrogen bonds between adjacent particles. The soft-agglomeration of the particles was confirmed by isolated particles in calcined Gd211 powders and in green compact, a narrow monomodal pore size distribution of the green compact and the low agglomeration coefficient of the calcined Gd211 powder. Extension this process to synthesis of BaCeO 3 , BaTiO 3 and Ce 0.8 Sm 0.2 O 1.9 powders, also led to weakly agglomerated nano-powders. It suggests that this method represents a powerful and facile method for the creation of doped and multi-component nano-sized ceramic powders.

  8. Nanosize Copper Dispersed Ionic Liquids As an Electrolyte of New Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Fu-Lin Chen

    2009-01-01

    Full Text Available To enhance the electrical conductivity of the electrolyte for a newly developed dye-sensitized solar cell (DSSC, metallic copper (Cu encapsulated within the carbon shell (Cu@C nanoparticles dispersed in a room temperature ionic liquid (RTIL (e.g., [bmim+][PF6−] has been studied in the present work. By the pulsed-field gradient spin-echo NMR method, the self-diffusion coefficients of cations and anions of the RTIL have been determined. The self-diffusion coefficient of the [bmim+] cations in the RTIL dispersed with 0.08% of Cu@C nanoparticles is increased by 35%. The electrical conductivity of the Cu@C dispersed RTIL is also increased by 65% (1.0 → 2.3 ms/cm. It is very clear the nanosize Cu@C dispersed RTIL with a relatively greater diffusion coefficient and electrical conductivity can be a very effective electrolyte especially utilized in DSSCs.

  9. Neocellularization and neovascularization of nanosized bioactive glass-coated decellularized trabecular bone scaffolds

    KAUST Repository

    Gerhardt, Lutz Christian

    2012-09-11

    In this study, the in vivo recellularization and neovascularization of nanosized bioactive glass (n-BG)-coated decellu-larized trabecular bone scaffolds were studied in a rat model and quantified using stereological analyses. Based on the highest amount of vascular endothelial growth factor (VEGF) secreted by human fibroblasts grown on n-BG coatings (0-1.245 mg/cm 2), decellularized trabecular bone samples (porosity: 43-81%) were coated with n-BG particles. Grown on n-BG particles at a coating density of 0.263 mg/cm2, human fibroblasts produced 4.3 times more VEGF than on uncoated controls. After 8 weeks of implantation in Sprague-Dawley rats, both uncoated and n-BG-coated samples were well infiltrated with newly formed tissue (47-48%) and blood vessels (3-4%). No significant differences were found in cellularization and vascularization between uncoated bone scaffolds and n-BG-coated scaffolds. This finding indicates that the decellularized bone itself may exhibit growth-promoting properties induced by the highly interconnected pore microarchitecture and/or proteins left behind on decellularized scaffolds. Even if we did not find proangiogenic effects in n-BG-coated bone scaffolds, a bioactive coating is considered to be beneficial to impart osteoinductive and osteoconductive properties to decellularized bone. n-BG-coated bone grafts have thus high clinical potential for the regeneration of complex tissue defects given their ability for recellularization and neovascularization. © 2012 Wiley Periodicals, Inc.

  10. In vivo screening to determine hazards of nanoparticles: Nanosized TiO2

    International Nuclear Information System (INIS)

    Drobne, Damjana; Jemec, Anita; Pipan Tkalec, Ziva

    2009-01-01

    A single-species laboratory test with terrestrial invertebrates was used to identify the hazard of nanosized TiO 2 . Feeding parameters, weight change, mortality, and the activities of catalase and glutathione-S-transferase were evaluated after 3 or 14 days of dietary exposure. The effects of nano-TiO 2 were dependent on exposure concentration and duration, total consumed quantity, size and pre-treatment of particles. The intensity of a response was ruled by duration of exposure and not by consumed quantity of nano-TiO 2 or exposure concentration as expected. The response to nano-TiO 2 is described as threshold-like. The exposure concentrations 10-1000 μg TiO 2 /g dry food (1.35-1025 μg of total consumed quantity of TiO 2 /g animal wet wt.) were identified as safe for tested species after tested exposure period. We conclude that the response to nanoparticles is different from that of soluble chemicals therefore these two types of data should be interpreted and processed differently. - The response of a biological system to nanoparticles is unique and depends on their physico-chemical characteristics, dose and duration of exposure

  11. Effects of nano-sized silicon dioxide on the structures and activities of three functional proteins

    International Nuclear Information System (INIS)

    Xu Zhen; Wang Shilong; Gao Hongwen

    2010-01-01

    Nanomaterials are finding increasing use in industrial production and daily life. However, human exposure to them may cause health risks. Nano-SiO 2 was selected as a representative nanomaterial and its potential effects were investigated in terms of its interactions with cytochrome c (cyt c), deoxyribonuclease (DNase II) and hemoglobin (Hb). The interactions accorded with Langmuir isothermal adsorption; the saturation binding numbers for cyt c, DNase II and Hb were 42 ± 5, 24 ± 2 and 1.1 ± 0.1 μmol/g nano-SiO 2 particle at pH 7.4, respectively, and the corresponding stability constants were 6.15 x 105, 1.79 x 106 and 2.6 x 107 M -1 . On the basis of the binding constants and of ζ-potential fluorescence and circular dichroism (CD) measurements and scanning electronic microscopy (SEM), it was found that the three functional proteins can bridge nano-SiO 2 particles via charge attraction and hydrogen bonding and aggregate them into coralloid forms. The interactions also changed the secondary structures of the proteins and inhibited their static and dynamic activities. It may reasonably be deduced that exposure to nano-size silicon dioxide particles e.g. as drug carriers may have an unfavorable effect on human health by inactivating functional proteins.

  12. On the surface magnetism induced atypical ferromagnetic behavior of cerium oxide (CeO2) nanoparticles

    Science.gov (United States)

    Sakara, M.; Arumugam, S.; Tripathy, S.; Balakumar, S.

    2012-06-01

    An investigation was made on the intrinsic ferromagnetic behavior of nano sized cerium oxide (ceria). The nanosized ceria was prepared by modified sol gel method with crystallite size around 7nm. Structural analysis was done by XRD which showed a single phase, impurity free fluorite type crystal structured of nano ceria. The morphological analysis by FESEM technique showed agglomerated nature of nanoparticles due to their high surface energy. The surface and bulk information was obtained from UV and visible Raman analysis. From Raman studies it was observed that the large surface defect which was the prime reason for the induced surface magnetism in the nano ceria. From magnetization studies by VSM, it was found that if magnetism was associated with the surface defects of the material. The ferromagnetic behavior of nanosized ceria is still under debate. An attempt has taken to explain the same with emphasizing the surface magnetism of ceria nanoparticles.

  13. Nano-sized Fe2O3/Fe3O4 facilitate anaerobic transformation of hexavalent chromium in soil-water systems.

    Science.gov (United States)

    Zhang, Yaxian; Li, Hua; Gong, Libo; Dong, Guowen; Shen, Liang; Wang, Yuanpeng; Li, Qingbiao

    2017-07-01

    The purpose of this study is to investigate the effects of nano-sized or submicro Fe 2 O 3 /Fe 3 O 4 on the bioreduction of hexavalent chromium (Cr(VI)) and to evaluate the effects of nano-sized Fe 2 O 3 /Fe 3 O 4 on the microbial communities from the anaerobic flooding soil. The results indicated that the net decreases upon Cr(VI) concentration from biotic soil samples amended with nano-sized Fe 2 O 3 (317.1±2.1mg/L) and Fe 3 O 4 (324.0±22.2mg/L) within 21days, which were approximately 2-fold of Cr(VI) concentration released from blank control assays (117.1±5.6mg/L). Furthermore, the results of denaturing gradient gel electrophoresis (DGGE) and high-throughput sequencing indicated a greater variety of microbes within the microbial community in amendments with nano-sized Fe 2 O 3 /Fe 3 O 4 than the control assays. Especially, Proteobacteria occupied a predominant status on the phylum level within the indigenous microbial communities from chromium-contaminated soils. Besides, some partial decrease of soluble Cr(VI) in abiotic nano-sized Fe 2 O 3 /Fe 3 O 4 amendments was responsible for the adsorption of nano-sized Fe 2 O 3 /Fe 3 O 4 to soluble Cr(VI). Hence, the presence of nano-sized Fe 2 O 3 /Fe 3 O 4 could largely facilitate the mobilization and biotransformation of Cr(VI) from flooding soils by adsorption and bio-mediated processes. Copyright © 2017. Published by Elsevier B.V.

  14. Interaction of nano-TiO2 with lysozyme: insights into the enzyme toxicity of nanosized particles.

    Science.gov (United States)

    Xu, Zhen; Liu, Xi-Wei; Ma, Yin-Sheng; Gao, Hong-Wen

    2010-03-01

    binding of lysozyme is dependent on the acidity and ion strength of the media. The bigger TiO(2) aggregate was formed in the presence of lysozyme where lysozyme may bridge between nano-TiO(2) particles. The coexistence of nano-TiO(2) particles resulted in the transition of lysozyme conformation from an alpha-helix into a beta-sheet and a substantial inactivation of lysozyme. The beta-sheet can induce the formation of amyloid fibrils, a process which plays a major role in pathology. Lysozyme was adsorbed on the nano-TiO(2) particle surface via electrostatic attraction and hydrogen bonds, and they also bridged among global nano-TiO(2) particles to form the colloidal particles. As a reasonable deduction of this study, nano-TiO(2) might have some toxic impacts on biomolecules. Our data suggest that careful attention be paid to the interaction of protein and nanomaterials. This could contribute to nanomaterial toxicity assessment. Our results strongly suggest that nano-TiO(2) has an obvious impact on biomolecules. Our data suggest that more attention should be paid to the potential toxicity of nano-TiO(2) on biomolecules. Further research into the toxicity of nanosized particles needs to be carried out prior to their cell toxicity and tissue toxicity. These investigations might serve as the basis for determining the toxicity and application of nanomaterials.

  15. Preparation, Characterization, and Biotoxicity of Nanosized Doped ZnO Photocatalyst

    Directory of Open Access Journals (Sweden)

    Lingling Liu

    2014-01-01

    Full Text Available Metal-doped nanosized ZnO (nZnO photocatalyst has been widely used for its typical properties and has thus gained considerable attention. In this study, five types of nZnO (nondoped nZnO, iron- (Fe- doped nZnO, cobalt- (Co- doped nZnO, nickel- (Ni- doped nZnO, and manganese- (Mn- doped nZnO materials were prepared through a wet chemical method and then exposed to Daphnia magna (D. magna at low and high concentrations (50 and 250 μg L−1. Results showed that the different metal-doped nZnOs had a variety of shapes and sizes and exhibited diverse dissolubility. After exposure tests, Zn accumulation, metallothionein (MT, and malondialdehyde (MDA contents in D. magna under 250 μg L−1 were significantly higher than those in the 50 μg L−1 groups. Compared with nondoped nZnO, Co-doped and Ni-doped nZnO enhanced Zn accumulation in D. magna whereas Mn-doped nZnO reduced such accumulation. MT and MDA contents in metal-doped nZnO (except Ni-nZnO treatments were lower than those in nondoped nZnO. Zn accumulation showed a negative relationship with dissolved Zn percentage, which can be explained by the swallowing of nZnO particles as an important pathway of D. magna ingestion. Sizes, dissolubility, and physiological functions of doping metals were the influencing factors on metal-doped nZnO biotoxicity to D. magna.

  16. Development of Nano-sized Oxide Dispersion Strengthened (ODS) Alloy for Nuclear Application

    International Nuclear Information System (INIS)

    Kim, Sung Soo; Jang, J. S; Kim, W. G.; Kim, D. W.; Han, C. H.; Ryu, H. J.; Kim, T. K.; Yang, S. K.; Kim, M. H.

    2009-08-01

    This research report is the 1st step of a 2-year period during a 5-year project, which is the development of nano-sized oxide dispersion strengthened (ODS) alloys for nuclear application. The manufacturing variables were investigated, and a suitable manufacturing process was established in order to establish a process for an isotropic ODS alloy. A spark plasma sintering (SPS) process was newly applied to enhance sintering before the application of a hydro-isostatic process (HIP). The minimum temperature for successful SPS for mechanical alloying is identified as 1050 .deg. C. The suitable HIP temperature and the hot roll temperature after the HIP process are identified as 1250 .deg. C. The highest strength appeared in the ODS alloy with an austenitic structure containing 0.5% Y 2 O 3 , a high temperature yield strength at 700 .deg. C, and a total elongation of 416 MPa and 17 %. It appeared that the directional difference in the strength and elongation between the longitudinal and transverse directions in the test alloy manufactured by a wet process was within 5%. The ODS alloy using both SPS and the HIP showed an impact energy of 7.7J using a KLST specimen. Creep rupture tests for 9 Cr ODS alloys were carried out to identify a creep rupture time at 700 .deg. C. A stress level of over 100 MPa was applied for the accelerated creep tests. The predicted creep rupture strength using an extrapolation method at 700 .deg. C for 10,000 hours was 63 MPa. The ion irradiation experiments on the Grade 92 and MA 956 at 440 and 570 .deg. C showed that the MA 956 ODS alloy exhibited a 1/3 level of swelling and a higher number of voids at 570 .deg. C. This seemed to be due to the fact that the oxide in the ODS alloy provided the preferential annihilation site for the point defects

  17. In vitro toxicity of nanosized copper particles in PC12 cells induced by oxidative stress

    Science.gov (United States)

    Xu, Pengjuan; Xu, Jing; Liu, Shichang; Ren, Guogang; Yang, Zhuo

    2012-06-01

    Recent evidence suggests that some nanomaterials, which are widely used in many fields, have health effects. In order to investigate the cytotoxicity induced by nanosized copper particles (nano-Cu), PC12 cells, which were widely used as an in vitro model for the neuron research, were treated with different concentrations (0, 1, 10, 30, and 100 μg/mL) of nano-Cu. The cell viability was determined by measurement of the reduction product of 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT). The oxidative stress induced by nano-Cu and its possible mechanism were studied in relation to the generation of reactive oxygen species (ROS) and the cellular activity of superoxide dismutase (SOD). Results showed that incubation of PC12 cells with increasing concentrations of nano-Cu induced a decrease of cell viability in a concentration- and time-dependent manner. In addition, flow cytometry assay using Annexin V-FITC/PI staining was used to investigate the mode of nano-Cu-induced cell death and quantified the percentage of apoptotic cells. Results showed that nano-Cu induced the significant apoptosis in PC12 cells. Meanwhile, intracellular accumulation of ROS was increased with the increased concentrations of nano-Cu and it was associated with decreased SOD activity, which was probably due to protect effects against the oxidative stress in PC12 cells. Results suggested that both excessive intracellular ROS and decreased SOD contributed to nano-Cu-induced cytotoxicity. In other words, the increasing of oxidative stress was a key mechanism in PC12 apoptosis induced by nano-Cu.

  18. Superior model for fault tolerance computation in designing nano-sized circuit systems

    Energy Technology Data Exchange (ETDEWEB)

    Singh, N. S. S., E-mail: narinderjit@petronas.com.my; Muthuvalu, M. S., E-mail: msmuthuvalu@gmail.com [Fundamental and Applied Sciences Department, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, Perak (Malaysia); Asirvadam, V. S., E-mail: vijanth-sagayan@petronas.com.my [Electrical and Electronics Engineering Department, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, Perak (Malaysia)

    2014-10-24

    As CMOS technology scales nano-metrically, reliability turns out to be a decisive subject in the design methodology of nano-sized circuit systems. As a result, several computational approaches have been developed to compute and evaluate reliability of desired nano-electronic circuits. The process of computing reliability becomes very troublesome and time consuming as the computational complexity build ups with the desired circuit size. Therefore, being able to measure reliability instantly and superiorly is fast becoming necessary in designing modern logic integrated circuits. For this purpose, the paper firstly looks into the development of an automated reliability evaluation tool based on the generalization of Probabilistic Gate Model (PGM) and Boolean Difference-based Error Calculator (BDEC) models. The Matlab-based tool allows users to significantly speed-up the task of reliability analysis for very large number of nano-electronic circuits. Secondly, by using the developed automated tool, the paper explores into a comparative study involving reliability computation and evaluation by PGM and, BDEC models for different implementations of same functionality circuits. Based on the reliability analysis, BDEC gives exact and transparent reliability measures, but as the complexity of the same functionality circuits with respect to gate error increases, reliability measure by BDEC tends to be lower than the reliability measure by PGM. The lesser reliability measure by BDEC is well explained in this paper using distribution of different signal input patterns overtime for same functionality circuits. Simulation results conclude that the reliability measure by BDEC depends not only on faulty gates but it also depends on circuit topology, probability of input signals being one or zero and also probability of error on signal lines.

  19. Targeted endothelial delivery of nanosized catalase immunoconjugates protects lung grafts donated after cardiac death.

    Science.gov (United States)

    Preissler, Gerhard; Loehe, Florian; Huff, Ines V; Ebersberger, Ulrich; Shuvaev, Vladimir V; Bittmann, Iris; Hermanns, Iris; Kirkpatrick, James C; Fischer, Karl; Eichhorn, Martin E; Winter, Hauke; Jauch, Karl W; Albelda, Steven M; Muzykantov, Vladimir R; Wiewrodt, Rainer

    2011-08-27

    Donor organ shortage represents a major problem in lung transplantation. Donation after cardiac death could help to expand the pool of organs, but the additional period of warm ischemia after cardiac arrest aggravates primary graft dysfunction. The pulmonary endothelium of the graft constitutes an important source and target of reactive oxygen species generated during ischemia and reperfusion. Targeted protection of graft pulmonary endothelial cells by the antioxidant enzyme catalase, conjugated with a platelet/endothelial cell adhesion molecule-1 (PECAM-1) antibody to nanosized particles (anti-PECAM/catalase conjugates), might improve outcome in lung transplantation using donors after cardiac death and prolonged hypothermic preservation. Left lung transplantation was performed in 18 pigs. Before cardiac arrest, donors received anti-PECAM/catalase, unconjugated component mixture or vehicle solution. After 90-min warm and 18-hr hypothermic ischemia, lungs were transplanted, and function was assessed during 6 hr after reperfusion. Samples of bronchoalveolar lavage fluid and lung tissue were taken thereafter. Six sham-operated animals served as controls. During 6-hr reperfusion, anti-PECAM/catalase significantly ameliorated graft function, evidenced by major improvements of gas exchange and reduced intrapulmonary shunt fraction. Furthermore, lipid peroxidation, alveolar leakage, and edema formation were reduced in protected grafts. Similarly moderate lung pathology was seen after transplantation. Augmentation of the antioxidant capacity of graft pulmonary endothelial cells with anti-PECAM/catalase nanoparticles represents a straightforward approach to enable a safe transplantation of prolonged preserved donation after cardiac death lungs. Anti-PECAM/catalase protection alleviated oxidative stress and allowed immediate reconstitution of normal gas exchange and pulmonary microcirculation, a prerequisite for improved graft and patient outcome.

  20. Nano-sized titanium dioxide toxicity in rat prostate and testis: Possible ameliorative effect of morin.

    Science.gov (United States)

    Shahin, Nancy N; Mohamed, Maha M

    2017-11-01

    This study investigated the effect of short-term oral exposure to nano-sized titanium dioxide (nTiO 2 ) on Wistar rat prostate and testis, and the associating reproductive-related alterations. The study also evaluated the potential ameliorative effect of the natural flavonoid, morin, on nTiO 2 -induced aberrations. Intragastric administration of nTiO 2 (50mg/kg/day for 1, 2 and 3weeks) increased testicular gamma-glutamyltransferase (γ-GT) activity and decreased testicular steroidogenic acute regulatory protein (StAR) and c-kit gene expression, serum testosterone level and sperm count. nTiO 2 -treated rats also exhibited prostatic and testicular altered glutathione levels, elevated TNF-α levels, up-regulated Fas, Bax and caspase-3 gene expression, down-regulated Bcl-2 gene expression and enhanced prostatic lipid peroxidation. Sperm malformation and elevated testicular acid phosphatase (ACP) activity and malondialdehyde level, serum prostatic acid phosphatase activity, prostate specific antigen (PSA), gonadotrophin and estradiol levels occurred after the 2 and 3week regimens. Morin (30mg/kg/day administered intragastrically for 5weeks) mitigated nTiO 2 -induced prostatic and testicular injury as evidenced by lowering serum PSA level, testicular γ-GT and ACP activities and TNF-α level, along with hampering both intrinsic and extrinsic apoptotic pathways. Moreover, morin alleviated prostatic lipid peroxidation, raised prostatic glutathione level, and relieved testicular reductive stress. Additionally, morin increased testicular StAR and c-kit mRNA expression, raised the sperm count, reduced sperm deformities and modified the altered hormone profile. Histopathological evaluation supported the biochemical findings. In conclusion, morin could ameliorate nTiO 2 -induced prostatic and testicular injury and the corresponding reproductive-related aberrations via redox regulatory, anti-inflammatory and anti-apoptotic mechanisms, promoting steroidogenesis and

  1. Flash combustion synthesis and characterisation of nanosized proton conducting Yttria-doped barium cerate

    Energy Technology Data Exchange (ETDEWEB)

    Jacquin, M.; Jing, Y.; Essoumhi, A.; Taillades, G.; Jones, D.J.; Roziere, J. [Montpellier Univ., Montpellier (France). Lab. des Agregats Moleculaires et Materiaux Inorganiques

    2007-10-15

    The high conversion efficiency of proton ceramic fuel cells renders them a promising technology for electric power conversion. They also function in an intermediate temperature range (400 to 600 degrees C) where the problem of thermal ageing can be avoided. This paper presented a newly developed flash combustion method for the preparation of proton conducting yttrium-doped barium cerate nanopowders. This quick, safe and low cost route takes advantage of the exothermic and self-sustaining redox reaction between high oxygen content metal salts and a suitable fuel that acts as a reducing agent. The parameters that influence the reaction product are the type of fuel, the fuel to oxidizer ratio, and the ignition temperature. Use of suitable fuel in combustion syntheses ensures stability of the chemical composition and high quality of products, and produces non-toxic gases. In this study, the flash combustion synthesis method was used to ignite the mixture at 600 degrees C. The resulting fine powder was characterized by transmission and scanning electron microscopy, and X-ray diffraction. The resulting nano-sized crystallites allow for the preparation of fully densified materials with densities up to 98 per cent. Water uptake was examined in compressed and sintered samples of BaCe{sub 0.9}Y{sub 0.1}O{sub 2.95} (BCY10). Bulk and total conductivities were determined with impedance spectroscopy in the range 300 to 600 degrees C. Densified yttria doped barium cerate materials show a bulk conductivity of 2.3 x 10{sup -2} S/cm and a total conductivity of 1.2 x 10{sup -2} S/cm at 500 degrees C. The temperature dependence was close to that of the bulk. It was concluded that flash combustion is an interesting alternative method for preparing proton conducting oxides for intermediate temperature fuel cells. 28 refs., 1 tab., 10 figs.

  2. Synthesis and Characterization of Nano-Sized Hexagonal and Spherical Nanoparticles of Zinc Oxide

    Directory of Open Access Journals (Sweden)

    M. A. Moghri Moazzen

    2012-09-01

    Full Text Available ZnO plays an important role in many semiconductors technological aspects.  Here,  direct  precipitation  method  was  employed  for  the synthesis of nano-sized hexagonal ZnO particles, which is based on chemical  reactions between  raw materials used  in  the  experiment. ZnO  nanoparticles  were  synthesized  by  calcinations  of  the  ZnO precursor precipitates  at 250  ˚C  for 3hours. The particle  size  and structure of the products have been confirmed by XRD. The FT-IR study  confirms  the  presence  of  functional  groups.  Also,  the morphology  and  size  distribution  of  ZnO  nanoparticles  was analyzed by TEM images. The optical properties were investigated by UV–Visible  spectroscopy. The XRD  results  show  that  the  size of  the prepared nanoparticles  is  in  the  range  of 20–40 nm, which this value  is  in good agreement with  the TEM  results. The FT-IR spectrum clearly indicates the formation of an interfacial chemical bond between Zn and O. Also  the UV absorption depends on  the particles  size  and morphology,  so  the  optical properties  enhances with  decreasing  nanoparticles  size.  Moreover  the  direct precipitation technique is a feasible method for production of ZnO nanopowders.

  3. Improving aqueous solubility and antitumor effects by nanosized gambogic acid-mPEG2000 micelles

    Directory of Open Access Journals (Sweden)

    Cai LL

    2013-12-01

    Full Text Available Lulu Cai,1,* Neng Qiu,2,* Mingli Xiang,3,* Rongsheng Tong,1 Junfeng Yan,1 Lin He,1 Jianyou Shi,1 Tao Chen,4 Jiaolin Wen,3 Wenwen Wang,3 Lijuan Chen31Department of Pharmacy, Sichuan Academy of Medical Science and Sichuan Provincial People's Hospital, 2College of Materials and Chemistry and Chemical Engineering, Chengdu University of Technology, 3State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu, People's Republic of China; 4Faculty of Pharmacy, University of Montreal, Montreal, QC, Canada *These authors contributed equally to this paperAbstract: The clinical application of gambogic acid, a natural component with promising antitumor activity, is limited due to its extremely poor aqueous solubility, short half-life in blood, and severe systemic toxicity. To solve these problems, an amphiphilic polymer-drug conjugate was prepared by attachment of low molecular weight (ie, 2 kDa methoxy poly(ethylene glycol methyl ether (mPEG to gambogic acid (GA-mPEG2000 through an ester linkage and characterized by 1H nuclear magnetic resonance. The GA-mPEG2000 conjugates self-assembled to form nanosized micelles, with mean diameters of less than 50 nm, and a very narrow particle size distribution. The properties of the GA-mPEG2000 micelles, including morphology, stability, molecular modeling, and drug release profile, were evaluated. MTT (3-(4,5-dimethylthiazol-2-yl-2,5 diphenyl tetrazolium bromide tests demonstrated that the GA-mPEG2000 micelle formulation had obvious cytotoxicity to tumor cells and human umbilical vein endothelial cells. Further, GA-mPEG2000 micelles were effective in inhibiting tumor growth and prolonged survival in subcutaneous B16-F10 and C26 tumor models. Our findings suggest that GA-mPEG2000 micelles may have promising applications in tumor therapy.Keywords: gambogic acid, poly(ethylene glycol-drug conjugate, micelle, antitumor, toxicity

  4. Maternal inhalation of surface-coated nanosized titanium dioxide (UV-Titan) in C57BL/6 mice

    DEFF Research Database (Denmark)

    Jackson, Petra; Halappanavar, Sabina; Hougaard, Karin Sorig

    2013-01-01

    We investigated effects of maternal pulmonary exposure to titanium dioxide (UV-Titan) on prenatally exposed offspring. Time-mated mice (C57BL/6BomTac) were inhalation exposed (1 h/day to 42 mg UV-Titan/m(3) aerosolised powder or filtered air) during gestation days (GDs) 8-18. We evaluated DNA...

  5. Effects of prenatal exposure to surface-coated nanosized titanium dioxide (UV-Titan). A study in mice

    DEFF Research Database (Denmark)

    Hougaard, Karin S.; Jackson, Petra; Jensen, Keld A.

    2010-01-01

    neurofunction and fertility. Physicochemical particle properties were determined to provide information on specific exposure and deposition. Results: Particles consisted of mainly elongated rutile titanium dioxide (TiO2) with an average crystallite size of 21 nm, modified with Al, Si and Zr, and coated...

  6. Twenty-eight-day repeated inhalation toxicity study of nano-sized lanthanum oxide in male sprague-dawley rats.

    Science.gov (United States)

    Shin, Seo-Ho; Lim, Cheol-Hong; Kim, Yong-Soon; Lee, Yong-Hoon; Kim, Sung-Hwan; Kim, Jong-Choon

    2017-04-01

    Although the use of lanthanum has increased in field of high-tech industry worldwide, potential adverse effects to human health and to the environment are largely unknown. The present study aimed to investigate the potential toxicity of nano-sized lanthanum oxide (La 2 O 3 ) following repeated inhalation exposure in male Sprague-Dawley rats. Male rats were exposed nose-only to nano-sized La 2 O 3 for 28 days (5 days/week) at doses of 0, 0.5, 2.5, and 10 mg/m 3 . In the experimental period, we evaluated treatment-related changes including clinical signs, body weight, hematology, serum biochemistry, necropsy findings, organ weight, and histopathology findings. We also analyzed lanthanum distribution in the major organs and in the blood, bronchoalveolar lavage fluids (BALF), and oxidative stress in lung tissues. Lanthanum level was highest in lung tissues and showed a dose-dependent relation. Alveolar proteinosis was observed in all treatment groups and was accompanied by an increase in lung weight; moreover, lung inflammation was observed in the 2.5 mg/m 3 and higher dose groups and was accompanied by an increase in white blood cells. In the BALF, total cell counts including macrophages and neutrophils, lactate dehydrogenase, albumin, nitric oxide, and tumor necrosis factor-alpha increased significantly in all treatment groups. Furthermore, these changes tended to deteriorate in the 10 mg/m 3 group at the end of the recovery period. In the present experimental conditions, we found that the lowest-observed-adverse-effect level of nano-sized La 2 O 3 was 0.5 mg/m 3 in male rats, and the target organ was the lung. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1226-1240, 2017. © 2016 Wiley Periodicals, Inc.

  7. Concentration-dependent systemic response after inhalation of nano-sized zinc oxide particles in human volunteers.

    Science.gov (United States)

    Monsé, Christian; Hagemeyer, Olaf; Raulf, Monika; Jettkant, Birger; van Kampen, Vera; Kendzia, Benjamin; Gering, Vitali; Kappert, Günther; Weiss, Tobias; Ulrich, Nadin; Marek, Eike-Maximilian; Bünger, Jürgen; Brüning, Thomas; Merget, Rolf

    2018-02-12

    Inhalation of high concentrations of zinc oxide particles (ZnO) may cause metal fume fever. In an earlier human inhalation study, no effects were observed after exposure to ZnO concentrations of 0.5 mg/m 3 . Further data from experimental studies with pure ZnO in the concentration range between 0.5 and 2.5 mg/m 3 are not available. It was the aim of this experimental study to establish the concentration-response relationship of pure nano-sized ZnO particles. Sixteen healthy subjects were exposed to filtered air and ZnO particles (0.5, 1.0 and 2.0 mg/m 3 ) for 4 h on 4 different days, including 2 h of cycling with a low workload. The effects were assessed before, immediately after, and about 24 h after each exposure. Effect parameters were symptoms, body temperature, inflammatory markers and clotting factors in blood, and lung function. Concentration-dependent increases in symptoms, body temperature, acute phase proteins and neutrophils in blood were detected after ZnO inhalation. Significant effects were detected with ZnO concentrations of 1.0 mg/m 3 or higher, with the most sensitive parameters being inflammatory markers in blood. A concentration-response relationship with nano-sized ZnO particles in a low concentration range was demonstrated. Systemic inflammatory effects of inhaled nano-sized ZnO particles were observed at concentrations well below the occpational exposure limit for ZnO in many countries. It is recommended to reassess the exposure limit for ZnO at workplaces.

  8. Hierarchically Porous Carbon Monoliths with High Surface Area from Bridged Poly(silsesquioxane) without Thermal Activation Process

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, G; Kanamori, K; Nakanishi, K; Hanada, T, E-mail: h_george@kuchem.kyoto-u.ac.jp [Department of Chemistry, Graduate School of Science, Kyoto University Kitashirakawa, Sakyo-ku, Kyoto (Japan)

    2011-10-29

    Hierarchically porous carbon monoliths with high specific surface areas have been fabricated by removing nano-sized silica phase from carbon/silica composites pyrolyzed from bridged poly(silsesquioxane). This activation method improves the homogeneity between inner and outer parts of the monoliths compared to the conventional thermal activation methods.

  9. Structure and properties of nanosize NiFe2O4 prepared by template and precipitation methods

    Czech Academy of Sciences Publication Activity Database

    Ćosović, A.; Ćosović, B.; Žák, Tomáš; David, Bohumil; Talijan, N.

    2013-01-01

    Roč. 49, č. 3 (2013), s. 271-277 ISSN 1450-5339 R&D Projects: GA ČR(CZ) GAP108/11/1350; GA MŠk(CZ) ED1.1.00/02.0068 Institutional research plan: CEZ:AV0Z2041904 Institutional support: RVO:68081723 Keywords : nanosized NiFe2O4 * template method * precipitation route * microstructure * phase composition * magnetic properties Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.135, year: 2013

  10. Novel processing of bioglass ceramics from silicone resins containing micro- and nano-sized oxide particle fillers.

    Science.gov (United States)

    Fiocco, L; Bernardo, E; Colombo, P; Cacciotti, I; Bianco, A; Bellucci, D; Sola, A; Cannillo, V

    2014-08-01

    Highly porous scaffolds with composition similar to those of 45S5 and 58S bioglasses were successfully produced by an innovative processing method based on preceramic polymers containing micro- and nano-sized fillers. Silica from the decomposition of the silicone resins reacted with the oxides deriving from the fillers, yielding glass ceramic components after heating at 1000°C. Despite the limited mechanical strength, the obtained samples possessed suitable porous architecture and promising biocompatibility and bioactivity characteristics, as testified by preliminary in vitro tests. © 2013 Wiley Periodicals, Inc.

  11. In utero exposure to nanosized carbon black (Printex90) does not induce tandem repeat mutations in female murine germ cells

    DEFF Research Database (Denmark)

    Boisen, Anne Mette Zenner; Shipley, Thomas; Jackson, Petra

    2013-01-01

    J mice were exposed four times during gestation by intratracheal instillation of 67μg/animal of nanosized carbon black Printex90 or vehicle (gestation days 7, 10, 15 and 18). Female offspring were raised to maturity and mated with unexposed CBA males. Expanded simple tandem repeat (ESTR) germline...... mutation rates in the resulting F2 generation were determined from full pedigrees (mother, father, offspring) of F1 female mice (178 CB-exposed and 258 control F2 offspring). ESTR mutation rates in CB-exposed F2 female offspring were not statistically different from those of F2 female control offspring....

  12. Innate defence functions of macrophages can be biased by nano-sized ceramic and metallic particles.

    Science.gov (United States)

    Lucarelli, Marilena; Gatti, Antonietta M; Savarino, Graziana; Quattroni, Paola; Martinelli, Lucia; Monari, Emanuela; Boraschi, Diana

    2004-01-01

    Nano-sized particles of ceramic and metallic materials are generated by high-tech industrial activities, and can be generated from worn-out replacement and prosthetic implants. The interaction with the human body of such nanoparticles has been investigated, with a particular emphasis on innate defence mechanisms. Human macrophages (PMA-differentiated myelomonocytic U-937 cells) were exposed in vitro to non-toxic concentrations of TiO(2), SiO(2), ZrO(2), or Co nanoparticles, and their inflammatory response (expression of TLR receptors and co-receptors, and cytokine production) was examined. Expression of TLR receptors was generally unaffected by exposure to the different nanoparticles, except for some notable cases. Exposure to nanoparticles of ZrO(2) (and to a lesser extent TiO(2)), upregulated expression of viral TLR receptors TLR3 and TLR7. Expression of TLR10 was also increased by TiO(2) and ZrO(2) nanoparticles. On the other hand, TLR9 expression was decreased by SiO(2) nano-particles, and expression of the co-receptor CD14 was inhibited by Co nanoparticles. Basal and LPS-induced production of cytokines IL-1beta, TNF-alpha, and IL-1Ra was examined in macrophages exposed to nanoparticles. SiO(2) nanoparticles strongly biased naive macrophages towards inflammation (M1 polarisation), by selectively inducing production of inflammatory cytokines IL-1beta and TNF-alpha. SiO(2) nanoparticles also significantly amplified the inflammatory phenotype of LPS-polarised M1 macrophages. Other ceramic nanoparticles had little influence on cytokine production, either in resting macrophages, or in LPS-activated cells. Generally, Co nanoparticles had an overall pro-inflammatory effect on naive macrophages, by reducing anti-inflammatory IL-1Ra and inducing inflammatory TNF-alpha. However, Co nanoparticles reduced production of IL-1beta and IL-1Ra, but not TNF-alpha, in LPS-polarised M1 macrophages. Thus, exposure to different nanoparticles can modulate, in different ways, the

  13. Development of nano-sized oxide dispersion strengthened (ODS) alloy for nuclear application

    International Nuclear Information System (INIS)

    Kim, Sung Soo; Jang, J. S.; Kim, W. G.; Kim, D. W.; Han, C. H.; Ryu, H. J.; Kim, T. K.; Yang, S. K.; Kim, M. H.

    2012-04-01

    This report is the activities of a 5 year project, including the 1st step for a 2-year period, and 2nd step for a 3-year period, which is the development of nano-sized oxide dispersion strengthened (ODS) alloys for nuclear application. The manufacturing variables were investigated in the ist step, and a suitable manufacturing process was established for an isotropic ODS alloy. The ODS alloy using both SPS and the HIP showed an impact energy of 7.7J using a KLST specimen. The predicted creep rupture strength of Fe-9Cr ODS using an extrapolation method at 700 .deg. C for 10,000 hours was 63 MPa. The creep-rupture strength of Fe-12Cr ODS steel at 104 hours 88 MPa which is higher than that of Fe-9Cr ODS by 25 MPa at 700. The YS at 700 .deg. C of Fe-12Cr-2Nb-1.1W-0.3Y2O3 showed over 300 MPa, which is 50% higher than that of Fe-12Cr-1.1W-0.3Y2O3. The tensile strength of Fe-12Cr-2Nb-1.1W-0.3Y2O3 is higher at all temperature. The fact that the YS of 2Nb alloy is higher at above 600.deg.C means that the addition of Nb may improve the creep resistance. The ion irradiation experiments on the Grade 92 and MA 956 at 440 and 570 .deg. C showed that the MA 956 ODS alloy exhibited a 1/3 level of swelling and a higher number of voids at 570 .deg. C. The reduction reaction of 2C+O2 ↑ 2CO is effective in removing certain forms of Cr oxide, as the enthalpy of CO formation is greater than that of Cr oxide at above 1050 .deg. C. Results of creep specimens by HRPD show that the creep damage is closely related to the (110) variation. The critical stress for the (110) lattice variation seems to be 90 MPa at 700 .deg. C. A trial cladding tube with a dimension of 10 mm in diameter, 1 mm in thickness, and 800 mm in length was finished by the 6th process. The high-temperature properties of the cladding tube were evaluated

  14. Phagocytosis of nano-sized titanium dioxide triggers changes in protein acetylation.

    Science.gov (United States)

    Sund, Jukka; Palomäki, Jaana; Ahonen, Niina; Savolainen, Kai; Alenius, Harri; Puustinen, Anne

    2014-08-28

    Nano-sized titanium dioxide (nTiO2) is one of the most produced engineered nanomaterials and therefore carries a high risk for workplace exposure. In several nanosafety studies, exposure to nTiO2 has been shown to trigger inflammation in mice lung and to cause oxidative stress. Here, cytoplasmic proteome changes in human monocyte derived macrophages were investigated with two-dimensional difference gel electrophoresis (2D-DIGE) and mass spectrometry to evaluate the adverse cellular effects after exposure to different types of TiO2 nanoparticles (NPs). Both studied TiO2 NPs (rutile TiO2 with or without silica coating) evoked similar proteome alterations. The identified proteins were linked to metabolic homeostasis, cytoskeleton remodeling and oxidative stress. The abundances of chloride intracellular channel protein 1 and cathepsin D changed only after exposure to nTiO2 as compared to a coarse particle analog. Enrichment analysis revealed that 70% of the proteins with changed intensities contained known acetylation sites, and it was possible to confirm a significant induction of cytoplasmic protein acetylation after nTiO2 exposure. The course of the events during phagocytosis could account for the observed membrane maintenance, metabolic and cytoskeletal protein expression changes. Lysine acetylation of cytoplasmic proteins in macrophages is emerging as a major cell regulation mechanism after nTiO2 exposure. While the amount of nanosafety research conducted in recent years has been constantly increasing, proteomics has not yet been utilized widely in this field. In addition, reversible protein post-translational modifications (PTMs) such as acetylation and phosphorylation have not been investigated in-depth in nanomaterial exposed cells. Proteome changes observed in nanomaterial exposed macrophages revealed active phagocytosis of the particles and provided new insights into underlying mechanisms of biological responses to nTiO2 exposures. Moreover, reversible

  15. Improved cytotoxicity of paclitaxel loaded in nanosized lipid carriers by intracellular delivery

    International Nuclear Information System (INIS)

    Miao, Jing; Du, Yongzhong; Yuan, Hong; Zhang, Xingguo; Li, Qian; Rao, Yuefeng; Zhao, Mengdan; Hu, Fuqiang

    2015-01-01

    Nanosized lipid carriers (NLC) can improve the limited drug-loading (DL) capacity and drug expulsion during storage, and adjust the drug release profile of solid lipid nanoparticles (SLN). In this study, Paclitaxel (PTX)-loaded NLC were prepared by solvent diffusion method using monostearin as solid lipid and oleic acid (OA) as liquid lipid matrix. The blank NLC with different OA content (the size range was from 89.5 ± 7.4 to 160.2 ± 34.6 nm) showed smaller size than the blank SLN (the size was 272.7 ± 43.6 nm), while the PTX-loaded NLC (the size range was from 481.3 ± 29.8 to 561.7 ± 38.3 nm) showed little bigger size, higher DL capacity, and faster drug in vitro release rate comparing with SLN (the size was 437.3 ± 68.2 nm). The 50 % cellular growth inhibitions (IC 50 ) of PTX-loaded NLC with 0, 5, 10, and 20 wt % OA were 0.92 ± 0.06, 0.69 ± 0.04, 0.25 ± 0.02, and 0.12 ± 0.02 µg mL −1 , respectively, while the IC 50 of Taxol TM was 1.72 ± 0.09 µg mL −1 . For analyzing cellular drug effect, cellular uptakes of fluorescent NLC and intracellular drug concentration were investigated. As the incorporation of OA into solid lipid matrix could accelerate both the cellular uptake and the PTX delivery, loaded by NLC, the cytotoxicity of PTX could be enhanced, and further enhanced by increasing OA content in NLC

  16. [Investigation on damage of bovine serum albumin (BSA) catalyzed by nano-sized silicon dioxide (SiO2) under ultrasonic irradiation using spectral methods].

    Science.gov (United States)

    Wang, Jun; Ding, Na; Zhang, Zhao-hong; Guo, Ying; Wang, Shi-xian; Xu, Rui; Zhang, Xiang-dong

    2009-04-01

    The damage of bovine serum albumin (BSA) molecules under ultrasonic irradiation in the presence of nano-sized silicon dioxide (SiO2) particles was studied by UV-Vis and fluorescence spectra. In addition, the influences of ultrasonic irradiation time, nano-sized SiO2 addition amount, solution acidity (pH) and ultrasonic irradiation power on the damage of BSA molecules in aqueous solution were also detected. For BSA solution of 1.0 x 10(-5) mol x L(-1) at (37.0+/-0.2) degrees C, the UV-Vis spectra of BSA solutions showed that the absorption peaks of BSA displayed obvious hyperchromic effect with the increase in some influence factors such as ultrasonic irradiation time, nano-sized SiO2 addition amount, pH value and ultrasonic irradiation power. However, the fluorescence spectra of BSA solutions showed the phenomenon of fluorescence quenching with the increase in ultrasonic irradiation time, nano-sized SiO2 addition amount, pH value and ultrasonic irradiation power. Moreover, the possible mechanism behind the damage of BSA molecule in the presence of nano-sized SiO2 powders under ultrasonic irradiation was discussed. It was considered that the damage of BSA molecules was attributed to the formation of *OH radicals resulting from the sonoluminescence and high-heat excitation of ultrasonic cavitation. The research results could be of great significance to using sonocatalytic method to treat tumour in clinic application and for developing nano-sized drug in the future.

  17. Enhancement of reactivity in Li4SiO4-based sorbents from the nano-sized rice husk ash for high-temperature CO2 capture

    International Nuclear Information System (INIS)

    Wang, Ke; Zhao, Pengfei; Guo, Xin; Li, Yimin; Han, Dongtai; Chao, Yang

    2014-01-01

    Highlights: • The Li 4 SiO 4 sorbent from nano-sized rice husk ash was prepared and characterized. • The Aerosil and Quartz were comparably used for synthesized Li 4 SiO 4 . • The structure of sorbent was depended on the morphology of heated silicon materials. • The pretreatment sorbent showed increase in the CO 2 uptake and kinetic behavior. • This promising sorbent also maintained higher capacities during the multiple cycles. - Abstract: Using the cost-effective, renewable and nano-sized of citric acid pretreatment rice husk ash (CRHA) as silicon source, high efficient Li 4 SiO 4 (lithium orthosilicate)-based sorbents (CRHA-Li 4 SiO 4 ) for high-temperature CO 2 capture were prepared through the solid-state reaction at lower temperature (700 °C). Two typical raw materials (nano-structured Aerosil and crystalline Quartz powders) were used to synthesize Li 4 SiO 4 sorbents (Aerosil-Li 4 SiO 4 and Quartz-Li 4 SiO 4 ) for comparison purposes. The phase composition behavior, surface area, and morphology of the silicon sources, heat treated raw materials and as-received Li 4 SiO 4 sorbents were studied by analytical techniques. The CO 2 adsorption capacity and adsorption–desorption performance were tested by the thermo-gravimetric analyses (CO 2 atmosphere) and a fixed bed reactor, respectively. Compared with the case of its original samples, the morphology of heat treated raw materials had a greater effect on the phase composition, microstructure, special surface area and CO 2 adsorption properties of their resulting sorbents. Although the calcined Quartz sample maintained the structure of micron particles, its reactivity was not enough to react completely with Li 2 CO 3 . Due to the greater reactivity of nanoparticles, Aerosil-Li 4 SiO 4 presented pure of Li 4 SiO 4 whereas it obtained large particles with dense morphology, which was coming from the pronounced fusing of silica nanoparticles during the calcined process. Conversely, CRHA-Li 4 SiO 4

  18. Evaluation of alloying effect on the formation of Ni-Fe nanosized powders by pulsed wire discharge

    International Nuclear Information System (INIS)

    Park, Gyu-Hyeon; Lee, Gwang-Yeob; Kim, Hyeon-Ah; Lee, A-Young; Oh, Hye-Ryeong; Kim, Song-Yi; Kim, Do-Hyang; Lee, Min-Ha

    2016-01-01

    Highlights: • Synthesizing Ni-Fe alloy nano-powder employing Ni-plating layer of Fe wire by PWD process. • The mean particle size is decreased with increasing the charging voltage affecting to the super heating factor (K). • The mean particle size of PWD Ni-Fe nanosized powder is accordance with applied voltage. • Uniformity of mean particel size can be controlled by adjusting charging voltage and super heating factor (K). - Abstract: This study investigates the effects of varying the explosion time and charging voltage of pulsed wire discharge (PWD) on the mean particle size, dispersibility and alloying reliability of powders produced from pure Ni and Ni-plated Fe wires. It was found that with increasing charging voltage, the mean particle size of Ni powders is reduced from 40.11 ± 0.23 to 25.63 ± 0.07 nm, which is attributed to a change in the extent of super heating with particle size. Nanosized powders of Ni-Fe alloy with a mean particle size between 25.91 ± 0.24 and 26.30 ± 0.26 nm were also successfully fabricated and found to consist of particles with a γ-(Ni/Fe) core and FeO shell. The reliability for the optimization of processing parameters to control particle sizes is also evaluated.

  19. A Facile Route toward the Increase of Oxygen Content in Nanosized Zeolite by Insertion of Cerium and Fluorinated Compounds

    Directory of Open Access Journals (Sweden)

    Sarah Komaty

    2018-01-01

    Full Text Available Enriching oxygen content within nanosized zeolite X (as synthesized Na-X by insertion of cerium (ion exchanged Ce-X and functionalization with bromoperfluoro-n-octane (fluorinated F-X is reported. The materials were fully characterized by powder X-ray diffraction (XRD, dynamic light scattering (DLS, zeta potential, thermogravimetric analysis (TGA, nitrogen adsorption, and nuclear magnetic resonance (19F NMR. The O2 adsorption in the zeolite samples at various concentrations (0 to 165 Torr at −196 °C was studied by in situ FTIR. The modification of nanosized zeolites did not alter their colloidal stability, crystallinity, porosity, and particle size distribution. The inclusion of cerium and bromoperfluoro-n-octane considerably increase the oxygen capacity by 33% for samples Ce-X and F-X in comparison to the as-synthesized Na-X zeolite. Further, toxicity tests revealed that these materials are safe, which opens the door for their implementation in medical applications, where controlled delivery of oxygen is highly desirable.

  20. Hydrothermal synthesis and electrochemical properties of nano-sized Co-Sn alloy anodes for lithium ion batteries

    International Nuclear Information System (INIS)

    He Jianchao; Zhao Hailei; Wang Jing; Wang Jie; Chen Jingbo

    2010-01-01

    Research highlights: → Nano-sized Co-Sn alloys were synthesized by hydrothermal route. → Li 2 O and CoSn can buffer the large volume change associated with lithiation of Sn. → A two-step reaction mechanism of CoSn 2 alloy during cycling was confirmed. - Abstract: Nano-sized Co-Sn alloys with a certain amount of Sn oxides used as potential anode materials for lithium ion batteries were synthesized by hydrothermal route. The effects of hydrothermal conditions and post annealing on the phase compositions and the electrochemical properties of synthesized powders were characterized by means of X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) with energy dispersive spectra (EDS) analysis and galvanostatic cycling tests. Prolonging the dwelling time at the same hydrothermal temperature can increase the content of Sn oxides, which will lead to a high initial irreversible capacity loss but a better cycling stability owing to the buffer effect of irreversible product Li 2 O. Heat-treatment can increase the crystallinity and cause the presence of a certain amount of inert CoSn component, which both have positive impact on the cycling stability of Co-Sn electrode. By comparison with the lithiation/delithiation processes of metal Sn, a two-step mechanism of CoSn 2 alloy during cycling was confirmed.

  1. A reversible adsorption-desorption interface of DNA based on nano-sized zirconia and its application.

    Science.gov (United States)

    Liu, Shou-Qing; Xu, Jing-Juan; Chen, Hong-Yuan

    2004-08-01

    It is essential for the information storage in DNA-based bio-chips to construct a reversible exchange interface of DNA. Here, a highly reproducible and reversible adsorption-desorption interface of DNA based on the nano-sized zirconia in different pH solution was successfully fabricated. The results showed that DNA can be adsorbed onto the nano-sized zirconia from its solution, and can desorb from the nanoparticles in 0.10 M KOH solution. When the matrix with nanoparticles returns to the DNA solution again, DNA can be re-adsorbed onto them as initial state. Moreover, the interaction of DNA with non-electroactive molecules, 2,2'-bipyridine, has been studied by electrochemistry method in the aid of probe Co(phen)(3)(3+). The experiments showed that when 2,2'-bipyridine was added into the test solution, the voltammetric peak currents of Co(phen)(3)(3+) decreased; and the decrease value of peak current against the concentration of 2,2'-bipyridine has a good Langmuir relationship, by which the equilibrium constant of interaction between 2,2'-bipyridine and DNA was estimated to be 1.57 x 10(4)M(-1).

  2. Turning Waste into Value: Nanosized Natural Plant Materials of Solanum incanum L. and Pterocarpus erinaceus Poir with Promising Antimicrobial Activities

    Directory of Open Access Journals (Sweden)

    Sharoon Griffin

    2016-04-01

    Full Text Available Numerous plants are known to exhibit considerable biological activities in the fields of medicine and agriculture, yet access to their active ingredients is often complicated, cumbersome and expensive. As a consequence, many plants harbouring potential drugs or green phyto-protectants go largely unnoticed, especially in poorer countries which, at the same time, are in desperate need of antimicrobial agents. As in the case of plants such as the Jericho tomato, Solanum incanum, and the common African tree Pterocarpus erinaceus, nanosizing of original plant materials may provide an interesting alternative to extensive extraction and isolation procedures. Indeed, it is straightforward to obtain considerable amounts of such common, often weed-like plants, and to mill the dried material to more or less uniform particles of microscopic and nanoscopic size. These particles exhibit activity against Steinernema feltiae or Escherichia coli, which is comparable to the ones seen for processed extracts of the same, respective plants. As S. feltiae is used as a model nematode indicative of possible phyto-protective uses in the agricultural arena, these findings also showcase the potential of nanosizing of crude “waste” plant materials for specific practical applications, especially—but not exclusively—in developing countries lacking a more sophisticated industrial infrastructure.

  3. Fabrication of nano-sized magnetic tunnel junctions using lift-off process assisted by atomic force probe tip.

    Science.gov (United States)

    Jung, Ku Youl; Min, Byoung-Chul; Ahn, Chiyui; Choi, Gyung-Min; Shin, Il-Jae; Park, Seung-Young; Rhie, Kungwon; Shin, Kyung-Ho

    2013-09-01

    We present a fabrication method for nano-scale magnetic tunnel junctions (MTJs), employing e-beam lithography and lift-off process assisted by the probe tip of atomic force microscope (AFM). It is challenging to fabricate nano-sized MTJs on small substrates because it is difficult to use chemical mechanical planarization (CMP) process. The AFM-assisted lift-off process enables us to fabricate nano-sized MTJs on small substrates (12.5 mm x 12.5 mm) without CMP process. The e-beam patterning has been done using bi-layer resist, the poly methyl methacrylate (PMMA)/ hydrogen silsesquioxane (HSQ). The PMMA/HSQ resist patterns are used for both the etch mask for ion milling and the self-aligned mask for top contact formation after passivation. The self-aligned mask buried inside a passivation oxide layer, is readily lifted-off by the force exerted by the probe tip. The nano-MTJs (160 nm x 90 nm) fabricated by this method show clear current-induced magnetization switching with a reasonable TMR and critical switching current density.

  4. Synthesis of nano-sized ZnO particles by co-precipitation method with variation of heating time

    Science.gov (United States)

    Purwaningsih, S. Y.; Pratapa, S.; Triwikantoro, Darminto

    2016-02-01

    Zinc oxide powders have been synthesized by a co-precipitation method at low temperature (85 °C), using zinc acetate dihydrate, ammonia, hydrochloric acid solutions as the reactants. A number of process parameters such as reaction temperature, solution basicity or pH and heating time are the main factors affecting the morphology and physical properties of the ZnO nanostructures. In this work the effect of heating time on the morphology and particles size were studied. The as-synthesized ZnO powders were characterized using transmission electron microscopy (TEM) and X-ray diffraction (XRD) techniques. The samples were also analyzed using Fourier transform infrared (FTIR). Rietveld refinement of XRD data confirms that ZnO crystallizes in the hexagonal wurtzite structure with high degree of purity and the (101) plane predominant. The XRD results show that the average crystallite sizes were about 66, 27 and 12 nm for 3, 4 and 5 h of heating times, respectively. The XRD analysis indicated that a fraction of nano-sized ZnO powders were in the form of aggregates, which was also verified by TEM image. The TEM photograph demonstrated that the nano-sized ZnO particles were a pseudo-spherical shape.

  5. Highly Water-Stable Novel Lanthanide Wheel Cluster Organic Frameworks Featuring Coexistence of Hydrophilic Cagelike Chambers and Hydrophobic Nanosized Channels.

    Science.gov (United States)

    Zhou, Yuan-Yuan; Shi, Yang; Geng, Bing; Bo, Qi-Bing

    2017-02-15

    In attempts to investigate the potential luminescent sensing materials for sensitive detection of environmental pollutants, a new family of lanthanide wheel cluster organic frameworks (Ln-WCOFs) UJN-Ln4 has been constructed by employing one of the cycloalkane dicarboxylic acid derivatives. Adopting different conformations, the ligand links Ln 4 second building units (SBUs) and Ln 24 tertiary building units (TBUs) to form a unique wheel cluster layer-pillared 3D framework featuring the coexistence of hydrophobic nanosized channels and trigonal antiprism arrays with hydrophilic cagelike chambers. Apart from charming structures, isostructural UJN-Ln4 displays interesting porous, water-stable features. Systematic luminescence studies demonstrate that solvent water molecules can enhance the emission intensity of solid-state UJN-Eu4. Acting as a recyclable luminescent probe, water-stable luminescent UJN-Eu4 exhibits superior "turn-off" detection for Fe 3+ and Cu 2+ ions in aqueous solutions. Due to the nanosized hydrophobic channels, UJN-Eu4 also shows highly sensitive sensing of sodium dodecyl benzenesulfonate (SDBS) via luminescence "turn-on" respondence, representing the first example of quantitatively detecting SDBS in aqueous solutions by employing luminescent lanthanide frameworks as fluorescent sensors. The results also open up the exploration of novel luminescent Ln-WCOFs exhibiting unique applications in sensitive detecting of harmful pollutants in aquatic environments.

  6. Kinetic Study of Oxygen Adsorption over Nanosized Au/γ-Al2O3 Supported Catalysts under Selective CO Oxidation Conditions

    Directory of Open Access Journals (Sweden)

    George Karaiskakis

    2012-04-01

    Full Text Available O2 adsorption is a key process for further understanding the mechanism of selective CO oxidation (SCO on gold catalysts. Rate constants related to the elementary steps of O2 adsorption, desorption and surface bonding, as well as the respective activation energies, over a nanosized Au/γ-Al2O3 catalyst, were determined by Reversed-Flow Inverse Gas Chromatography (RF-IGC. The present study, carried-out in a wide temperature range (50–300 °C, both in excess as well as in the absence of H2, resulted in mechanistic insights and kinetic as well as energetic comparisons, on the sorption processes of SCO reactants. In the absence of H2, the rate of O2 binding, over Au/γ-Al2O3, drastically changes with rising temperature, indicating possible O2 dissociation at elevated temperatures. H2 facilitates stronger O2 bonding at higher temperatures, while low temperature binding remains practically unaffected. The lower energy barriers observed, under H2 rich conditions, can be correlated to O2 dissociation after hydrogenation. Although, H2 enhances both selective CO reactant’s desorption, O2 desorption is more favored than that of CO, in agreement with the well-known mild bonding of SCO reactant’s at lower temperatures. The experimentally observed drastic change in the strength of CO and O2 binding is consistent both with well-known high activity of SCO at ambient temperatures, as well as with the loss of selectivity at higher temperatures.

  7. Kinetic Study of Oxygen Adsorption over Nanosized Au/γ-Al2O3 Supported Catalysts under Selective CO Oxidation Conditions

    Directory of Open Access Journals (Sweden)

    George Karaiskakis

    2012-04-01

    Full Text Available O2 adsorption is a key process for further understanding the mechanism of selective CO oxidation (SCO on gold catalysts. Rate constants related to the elementary steps of O2 adsorption, desorption and surface bonding, as well as the respective activation energies, over a nanosized Au/γ-Al2O3 catalyst, were determined by Reversed-Flow Inverse Gas Chromatography (RF-IGC. The present study, carried-out in a wide temperature range (50–300 °C, both in excess as well as in the absence of H2, resulted in mechanistic insights and kinetic as well as energetic comparisons, on the sorption processes of SCO reactants. In the absence of H2, the rate of O2 binding, over Au/γ-Al2O3, drastically changes with rising temperature, indicating possible O2 dissociation at elevated temperatures. H2 facilitates stronger O2 bonding at higher temperatures, while low temperature binding remains practically unaffected. The lower energy barriers observed, under H2 rich conditions, can be correlated to O2 dissociation after hydrogenation. Although, H2 enhances both selective CO reactant’s desorption, O2 desorption is more favored than that of CO, in agreement with the well-known mild bonding of SCO reactant’s at lower temperatures. The experimentally observed drastic change in the strength of CO and O2 binding is consistent both with well-known high activity of SCO at ambient temperatures, as well as with the loss of selectivity at higher temperatures.

  8. Oxidative stress-induced cytotoxic and genotoxic effects of nano-sized titanium dioxide particles in human HaCaT keratinocytes.

    Science.gov (United States)

    Jaeger, Alexandra; Weiss, Dieter G; Jonas, Ludwig; Kriehuber, Ralf

    2012-06-14

    Since nano-sized particles (NPs) are increasingly used in various fields of innovative biomedicine and industrial technologies, it is of importance to identify their potential human health risk. We investigated whether ROS-induced mitochondrial DNA damage is the mode of action of titanium dioxide-NPs (TiO2-NPs; ≤20 nm) to induce cytotoxic and genotoxic effects in human HaCaT keratinocytes in vitro. We showed that TiO2-NPs accumulate at the cell surface and are taken up by endocytosis. Micronucleus (MN) formation was found to be significantly maximal increased 24 h after treatment with 10 μg/ml and 48 h after treatment with 5 μg/ml TiO2-NPs about 1.8-fold respectively 2.2-fold of control. Mitochondrial DNA damage measured as "common deletion" was observed to be significantly 14-fold increased 72 h after treatment with 10 μg/ml TiO2-NPs when compared to control. Four hours after treatment with 5 and 50 μg/ml TiO2-NPs the level of ROS in HaCaT cells was found to be significantly increased about 7.5-fold respectively 16.7-fold of control. In conclusion, for the first time we demonstrate the induction of the mitochondrial "common deletion" in HaCaT cells following exposure to TiO2-NPs, which strongly suggests a ROS-mediated cytotoxic and genotoxic potential of NPs. However, the effects of the modification of TiO2-NPs, such as agglomeration, size distribution pattern and exposure time have to be further critically examined. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  9. Development of a Sensitive Electrochemical Enzymatic Reaction-Based Cholesterol Biosensor Using Nano-Sized Carbon Interdigitated Electrodes Decorated with Gold Nanoparticles.

    Science.gov (United States)

    Sharma, Deepti; Lee, Jongmin; Seo, Junyoung; Shin, Heungjoo

    2017-09-15

    We developed a versatile and highly sensitive biosensor platform. The platform is based on electrochemical-enzymatic redox cycling induced by selective enzyme immobilization on nano-sized carbon interdigitated electrodes (IDEs) decorated with gold nanoparticles (AuNPs). Without resorting to sophisticated nanofabrication technologies, we used batch wafer-level carbon microelectromechanical systems (C-MEMS) processes to fabricate 3D carbon IDEs reproducibly, simply, and cost effectively. In addition, AuNPs were selectively electrodeposited on specific carbon nanoelectrodes; the high surface-to-volume ratio and fast electron transfer ability of AuNPs enhanced the electrochemical signal across these carbon IDEs. Gold nanoparticle characteristics such as size and morphology were reproducibly controlled by modulating the step-potential and time period in the electrodeposition processes. To detect cholesterol selectively using AuNP/carbon IDEs, cholesterol oxidase (ChOx) was selectively immobilized via the electrochemical reduction of the diazonium cation. The sensitivity of the AuNP/carbon IDE-based biosensor was ensured by efficient amplification of the redox mediators, ferricyanide and ferrocyanide, between selectively immobilized enzyme sites and both of the combs of AuNP/carbon IDEs. The presented AuNP/carbon IDE-based cholesterol biosensor exhibited a wide sensing range (0.005-10 mM) and high sensitivity (~993.91 µA mM -1 cm -2 ; limit of detection (LOD) ~1.28 µM). In addition, the proposed cholesterol biosensor was found to be highly selective for the cholesterol detection.

  10. Polyether ether ketone implants achieve increased bone fusion when coated with nano-sized hydroxyapatite: a histomorphometric study in rabbit bone

    Directory of Open Access Journals (Sweden)

    Johansson P

    2016-04-01

    Full Text Available Pär Johansson,1 Ryo Jimbo,1 Yoshihito Naito,2 Per Kjellin,3 Fredrik Currie,3 Ann Wennerberg1 1Department of Prosthodontics, Faculty of Odontology, Malmö University, Malmö, Sweden; 2Oral Implant Center, Tokushima University Hospital, Tokushima, Japan; 3Promimic AB, Stena Center, Göteborg, Sweden Abstract: Polyether ether ketone (PEEK possesses excellent mechanical properties similar to those of human bone and is considered the best alternative material other than titanium for orthopedic spine and trauma implants. However, the deficient osteogenic properties and the bioinertness of PEEK limit its fields of application. The aim of this study was to limit these drawbacks by coating the surface of PEEK with nano-scaled hydroxyapatite (HA minerals. In the study, the biological response to PEEK, with and without HA coating, was investigated. Twenty-four screw-like and apically perforated implants in the rabbit femur were histologically evaluated at 3 weeks and 12 weeks after surgery. Twelve of the 24 implants were HA coated (test, and the remaining 12 served as uncoated PEEK controls. At 3 weeks and 12 weeks, the mean bone–implant contact was higher for test compared to control (P<0.05. The bone area inside the threads was comparable in the two groups, but the perforating hole showed more bone area for the HA-coated implants at both healing points (P<0.01. With these results, we conclude that nano-sized HA coating on PEEK implants significantly improved the osteogenic properties, and in a clinical situation this material composition may serve as an implant where a rapid bone fusion is essential. Keywords: HA, PEEK, osseointegration, histology, orthopedics, in vivo

  11. Designing high-temperature steels via surface science and thermodynamics

    Science.gov (United States)

    Gross, Cameron T.; Jiang, Zilin; Mathai, Allan; Chung, Yip-Wah

    2016-06-01

    Electricity in many countries such as the US and China is produced by burning fossil fuels in steam-turbine-driven power plants. The efficiency of these power plants can be improved by increasing the operating temperature of the steam generator. In this work, we adopted a combined surface science and computational thermodynamics approach to the design of high-temperature, corrosion-resistant steels for this application. The result is a low-carbon ferritic steel with nanosized transition metal monocarbide precipitates that are thermally stable, as verified by atom probe tomography. High-temperature Vickers hardness measurements demonstrated that these steels maintain their strength for extended periods at 700 °C. We hypothesize that the improved strength of these steels is derived from the semi-coherent interfaces of these thermally stable, nanosized precipitates exerting drag forces on impinging dislocations, thus maintaining strength at elevated temperatures.

  12. Assessment of evidence for nanosized titanium dioxide-generated DNA strand breaks and oxidatively damaged DNA in cells and animal models

    DEFF Research Database (Denmark)

    Møller, Peter; Jensen, Ditte Marie; Wils, Regitze Sølling

    2017-01-01

    Nanosized titanium dioxide (TiO2) has been investigated in numerous studies on genotoxicity, including comet assay endpoints and oxidatively damaged DNA in cell cultures and animal models. The results have been surprisingly mixed, which might be attributed to physico-chemical differences...

  13. A novel copper (II) complex containing a tetradentate Schiff base: Synthesis, spectroscopy, crystal structure, DFT study, biological activity and preparation of its nano-sized metal oxide

    Science.gov (United States)

    Tohidiyan, Zeinab; Sheikhshoaie, Iran; Khaleghi, Mouj; Mague, Joel T.

    2017-04-01

    A new nano-sized copper (II) complex, [Cu(L)] with a tetra dentate Schiff base ligand, 2-((E)-(2-(E-5- bromo-2-hydroxybezenylideneamino) methyl)-4-bromophenol [H2L] was prepared by the reaction between of Cu (CH3COO)2·2H2O and (H2L) ligand with the ratio of 1:1, at the present of triethylamine by sonochemical method. The structure of [Cu (L)] complex was determined by FT-IR, UV-Vis, FESEM and molar conductivity. The structure of [Cu (L)] complex was characterized by single crystal X-ray diffraction. The geometry of [Cu (L)] complex was optimized using density functional theory (DFT) method with the B3LYP/6-31(d) level of theory. The calculated bond lengths and bond angles are in good agreement with the X-ray data. This complex was used as a novel precursor for preparing of CuO nano particles by the thermal decomposition method. The antibacterial activities of [H2L] ligand, nano-sized [Cu (L)] complex and nano-sized CuO have been screened against various strains of bacteria. According to the results, nano-sized CuO can be considered as an appropriate antibiotic agent.

  14. Propagation of electro-kinetic waves in magnetized GaN semiconductor with nano-sized ion colloids

    International Nuclear Information System (INIS)

    Saxena, Ajay; Sharma, Giriraj; Jat, K. L.; Rishi, M. P.

    2015-01-01

    Based on hydrodynamic model of multi-component plasma, an analytical study on propagation of longitudinal electro-kinetic (LEK) waves in wurtzite and zincblende structures of GaN is carried out. Nano-sized ion colloids (NICs) are embedded in the sample by the technique of ion-implantation. The implanted NICs are considered massive by an order as compared to the host lattice points and do not participate in Based LEK perturbations. Though, the NICs are continuously bombarded by the electrons as well as the holes yet, the former acquires a net negative charge owing to relatively higher mobility of electrons and consequently results into depletion of electron density in the medium. It i s found that the presence of charged NICs significantly modifies the dispersion and amplification characteristics of LEK waves in magnetized GaN semiconductor plasma and their role becomes increasingly effective as the fraction of charge on them increases

  15. Formation of magnetic microstructure of the nanosized NiFe2O4 synthesized via solid-state reaction

    Directory of Open Access Journals (Sweden)

    Žák T.

    2012-01-01

    Full Text Available Magnetic NiFe2O4 structure formation was studied through structural, compositional and magnetic characterization of obtained reaction products of a simple, high yielding and low-cost solid-state reaction. Initial annealing of the starting oxides mixture at 700ºC did not allow us to observe formation of the desired magnetic phase. In contrast, subsequent thermomagnetic measurements up to 800ºC indicated the considerable increase of the magnetic moment, which can be reasonably assigned to the changes in phase composition and formation of magnetic NiFe2O4 structure during the heating cycle of measurements. Nanosized NiFe2O4 phase formation has been confirmed by the following XRD and MS phase analyses and its nanocrystalline structure by XRD and SEM/TEM techniques. The obtained hysteresis loop taken after TM measurements suggest the increased volume of magnetically active material and thus additionally support the previous findings.

  16. Comparison of nano-sized Mn oxides with the Mn cluster of photosystem II as catalysts for water oxidation.

    Science.gov (United States)

    Najafpour, Mohammad Mahdi; Ghobadi, Mohadeseh Zarei; Haghighi, Behzad; Tomo, Tatsuya; Shen, Jian-Ren; Allakhverdiev, Suleyman I

    2015-02-01

    "Back to Nature" is a promising way to solve the problems that we face today, such as air pollution and shortage of energy supply based on conventional fossil fuels. A Mn cluster inside photosystem II catalyzes light-induced water-splitting leading to the generation of protons, electrons and oxygen in photosynthetic organisms, and has been considered as a good model for the synthesis of new artificial water-oxidizing catalysts. Herein, we surveyed the structural and functional details of this cluster and its surrounding environment. Then, we review the mechanistic findings concerning the cluster and compare this biological catalyst with nano-sized Mn oxides, which are among the best artificial Mn-based water-oxidizing catalysts. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Size Effect on the Structural and Magnetic Properties of Nanosized Perovskite LaFeO3 Prepared by Different Methods

    Directory of Open Access Journals (Sweden)

    Nguyen Thi Thuy

    2012-01-01

    Full Text Available Nanosized LaFeO3 material was prepared by 3 methods: high energy milling, citrate gel, and coprecipitation. The X-ray diffraction (XRD, differential scanning calorimetry (DSC, and thermogravimetric analysis (TGA show that the orthorhombic LaFeO3 phase was well formed at a low sintering temperature of 500°C in the citrate-gel and co-precipitation methods. Scanning electron microscope (SEM and transmission electron microscope (TEM observations indicate that the particle size of the LaFeO3 powder varies from 10 nm to 50 nm depending on the preparation method. The magnetic properties through magnetization versus temperature M(T and magnetization verses magnetic field M(H characteristics show that the nano-LaFeO3 exhibits a weak ferromagnetic behavior in the room temperature, and the M(H curves are well fitted by Langevin functions.

  18. Microstructure and corrosion resistance of Ni-based alloy laser coatings with nanosize CeO2 addition

    OpenAIRE

    Hong Zhang, Shi; Xi Li, Ming; Hong Yoon, Jae; Yul Cho, Tong; Zhu He, Yi; Gyu Lee, Chan

    2008-01-01

    Micron-size Ni-base alloy (NBA) powders were mixed with both 1.5 wt.% (hereinafter %) micron-size CeO2 (m-CeO2) and also 1.5% and 3.0% nano-size CeO2 (n- CeO2) powders. These mixtures were coated on low-carbon steel (Q235) by 2.0 kW CO2 laser cladding. The effects on the microstructures, phases and electrochemical corrosion of the coatings upon the addition of m- and n- CeO2 powders to NBA (m- and n- CeO2 /NBA) have been investigated. The results showed that a smooth coating was prep...

  19. Microstructure and corrosion resistance of Ni-based alloy laser coatings with nanosize CeO2 addition

    OpenAIRE

    Shi Hong Zhang et al

    2008-01-01

    Micron-size Ni-base alloy (NBA) powders were mixed with both 1.5 wt.% (hereinafter %) micron-size CeO2 (m-CeO2) and also 1.5% and 3.0% nano-size CeO2 (n- CeO2) powders. These mixtures were coated on low-carbon steel (Q235) by 2.0 kW CO2 laser cladding. The effects on the microstructures, phases and electrochemical corrosion of the coatings upon the addition of m- and n- CeO2 powders to NBA (m- and n- CeO2 /NBA) have been investigated. The results showed that a smooth coating was prepared unde...

  20. Detection of liquid petroleum gas using mixed nanosized tungsten oxide-based thick-film semiconductor sensor.

    Science.gov (United States)

    Chaudhari, G N; Bende, A M; Bodade, A B; Patil, S S; Manorama, S V

    2006-03-15

    The thick-film semiconductor sensor for liquid petroleum gas (LPG) detection was fabricated using a mixed WO(3)-based sensor. We present the characterization of both their structural properties by means of XRD measurements and the electrical characteristics by using gas-sensing properties. The sensing characteristics such as sensitivity, working range, cross-sensitivity and response time were studied by using nanosized WO(3)-based mixed with different metal oxides (SnO(2), TiO(2) and In(2)O(3)) and doped with noble metals (Au, Pd and Pt). The WO(3)-based mixed with 5 wt.% In(2)O(3) and 0.5 wt.% Pd showed the higher sensing characteristic at low concentration of LPG sensor at an operating temperature 225 degrees C.

  1. Cluster Study of Anion Specificity in Solutions: From Molecular-Like Species to Nano-Sized Droplets

    Science.gov (United States)

    Wang, Xue-Bin

    2015-03-01

    In this talk, I will present our cluster approach using size-selected, low-temperature photoelectron spectroscopy and ab initio calculations to study a variety of complex anion solvation across the Hofmeister series. Pronounced anion specific effects and rich solute-solvent, solvent-solvent interactions have been discovered en-route to solvation evolution from molecular-like species to nano-sized droplets. We found significant solute anisotropy effects in preferably selecting solvent network to align solute permanent dipole with the solvent electric field in hydrated neutral clusters. Thermodynamic advantage of organic acids in facilitating formation of bisulfate ion clusters, an important issue related to atmospheric chemistry and aerosol particle formation will also be discussed. This work was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences.

  2. Using Radiochromic Films to Characterize the Dispersion of ZrO{sub 2} Nano-sized Grain Clusters in Protective Polymer Composites

    Energy Technology Data Exchange (ETDEWEB)

    Fontainha, C.C.P.; Nolasco, A.V. [Depto. de Engenharia Nuclear - DEN / UFMG - MG, Av. Antonio Carlos 6627, 31270-970 Belo Horizonte, MG (Brazil); Santos, A.P.; Faria, L.O. [Centro de Desenvolvimento da Tecnologia Nuclear, Av. Antonio Carlos 6627, C.P. 941, 30270-901, Belo Horizonte, MG (Brazil)

    2015-07-01

    Radiation dosimetry is commonly used to prevent deterministic radiation effects in high dose medical procedures. Radiochromic films find nowadays widely application in radiotherapy, interventional procedures and CT exams for isodose and maximum skin dose measurements. Moreover the size of the irradiated area and its distribution can be performed through the reading of the individual components in the RGB-spectrum. Particularly, radiochromic film has multiple advantages over alternative dosimeters for low-kV X-rays dosimetry. Concerned to spatial resolution it is far superior to that of ionization chambers and thermoluminescent dosimeters. For high energy photon fields (keV to MeV) the most used radiochromic film commercially available belongs to the EBT Gafchromic{sup R} series. On the other hand, for low energy photon fields in the x-ray range (20 kVp to 200 kVp) the best choice belongs to the XR-QA Gafchromic{sup R} film series. In this work we demonstrate the possibility of generating 2D images of thin polymeric composites films using EBT3 and XR-QA2 Gafchromic{sup R} films exposed to 6 MeV and 40 keV x-ray photons, respectively, using the digital filtering tools of the ImageJ{sup R} free software. In this context, EBT3 films were placed on the surface of a rigid anthropomorphic phantom. Then, they were covered with a thermoplastic mask made of PCL polymer. This setup was then exposed to 2.0 Gy absorbed dose in the Linear Accelerator beam. The EBT3 films were then scanned in the high resolution mode in a commercial scanner and the images subsequently treated with digital filters. It is somehow possible to see the image of the thermoplastic mask in the scanned image. However, in the treated image it is easy to observe the mask arrangement. The unexpected phenomenon here is the EB3 film ability to detect the attenuation of high energy photons by a plastic material, which in turn has a very low mass-energy attenuation coefficient, producing a very clear 2D image

  3. Morphology and phase identification of micron to nanosized manganese oxide (MnO) with variations in sintering time

    Science.gov (United States)

    Sasongko, Muhammad Ilman Nur; Puspitasari, Poppy; Yazirin, Cepi; Tsamroh, Dewi Izzatus; Risdanareni, Puput

    2017-09-01

    Manganese oxide (MnO) occurs in many rock types and may take the form of minerals. MnO has its drawbacks, namely highly reactive oxidizing species classified as dangerous and explosive at temperatures above 55 °C. Despite this,MnO has excellent magnetic, electrochemical, and conductivity properties, which should be reduced to nano-size to maximize their use and improve the properties of MnO. Phase and morphology characterization of powder this research aims to reduce the grain size of the MnO from micro to nano using the sol-gel method with various sintering times. Sol-gel is a simple synthesis method that has been proven capable of synthesizing a wide variety of micro-sized oxide materials into nano. Sintering time is a technique performed in the synthesis process to dry the material to a temperature above the normal temperature. The temperature used for sintering starting from 600 °C to 1000 °C. Characterizations were done using XRD, SEM, EDX, and FTIR machines. The sintering processes in this study used a temperature of 600 °C with different sintering periods of 30, 60 and 90 minutes. The XRD characterization with a 30-minute sintering time resulted in the smallest MnO in the form crystalline powder of 47.3 nm. The highest intensity (degree of crystallinity) found in MnO sintered for 90 minutes. The results of the morphological characterization of SEM showed a morphological change in MnO from micro-sized triangular to nano-sized spherical shape. The EDX characterization results indicated that the 30-minute sintering caused the lowest change in Mn and the highest change in O. The results of FTIR characterization showed a shift in C-H and Mn-O followed by an increase in the group of N-H, C=O and Mn-O.

  4. Thermal conductivity enhancement and sedimentation reduction of magnetorheological fluids with nano-sized Cu and Al additives

    Science.gov (United States)

    Rahim, M. S. A.; Ismail, I.; Choi, S. B.; Azmi, W. H.; Aqida, S. N.

    2017-11-01

    This work presents enhanced material characteristics of smart magnetorheological (MR) fluids by utilizing nano-sized metal particles. Especially, enhancement of thermal conductivity and reduction of sedimentation rate of MR fluids those are crucial properties for applications of MR fluids are focussed. In order to achieve this goal, a series of MR fluid samples are prepared using carbonyl iron particles (CIP) and hydraulic oil, and adding nano-sized particles of copper (Cu), aluminium (Al), and fumed silica (SiO2). Subsequently, the thermal conductivity is measured by the thermal property analyser and the sedimentation of MR fluids is measured using glass tubes without any excitation for a long time. The measured thermal conductivity is then compared with theoretical models such as Maxwell model at various CIP concentrations. In addition, in order to show the effectiveness of MR fluids synthesized in this work, the thermal conductivity of MRF-132DG which is commercially available is measured and compared with those of the prepared samples. It is observed that the thermal conductivity of the samples is much better than MRF-132DG showing the 148% increment with 40 vol% of the magnetic particles. It is also observed that the sedimentation rate of the prepared MR fluid samples is less than that of MRF-132DG showing 9% reduction with 40 vol% of the magnetic particles. The mixture optimized sample with high conductivity and low sedimentation was also obtained. The magnetization of the sample recorded an enhancement of 70.5% when compared to MRF-132DG. Furthermore, the shear yield stress of the sample were also increased with and without the influence of magnetic field.

  5. Coordination polymer-derived nano-sized zinc ferrite with excellent performance in nitro-explosive detection.

    Science.gov (United States)

    Singha, Debal Kanti; Mahata, Partha

    2017-08-29

    Herein, a mixed metal coordination polymer, {(H 2 pip)[Zn 1/3 Fe 2/3 (pydc-2,5) 2 (H 2 O)]·2H 2 O} 1 {where H 2 pip = piperazinediium and pydc-2,5 = pyridine-2,5-dicarboxylate}, was successfully synthesized using a hydrothermal technique. To confirm the structure and phase purity of 1, single crystals of an isomorphous pure Fe compound, {(H 2 pip)[Fe(pydc-2,5) 2 (H 2 O)]·2H 2 O} 1a, were synthesized based on similar synthetic conditions. Single crystal X-ray data of 1a confirmed the one-dimensional anionic metal-organic coordination polymer hydrogen bonded with protonated piprazine (piperazinediium) and lattice water molecules. The phase purity of 1 and 1a were confirmed via powder X-ray diffraction. Compound 1 was systematically characterized using IR, TGA, SEM, and EDX elemental mapping analysis. Compound 1 was used as a single source precursor for the preparation of nano-sized ZnFe 2 O 4 via thermal decomposition. The as-obtained ZnFe 2 O 4 was fully characterized using PXRD, SEM, TEM, and EDX elemental mapping analysis. It was found that ZnFe 2 O 4 was formed in its pure form with particle size in the nano-dimension. The aqueous dispersion of nano-sized ZnFe 2 O 4 exhibits a strong emission at 402 nm upon excitation at 310 nm. This emissive property was employed for luminescence-based detection of nitroaromatic explosives in an aqueous medium through luminescence quenching for the first time. Importantly, selective detections have been observed for phenolic nitroaromatics based on differential luminescence quenching behaviour along with a detection limit of 57 ppb for 2,4,6-trinitrophenol (TNP) in water.

  6. Development of a website and biobank database for the Nanosized Cancer Polymarker Biochip Project: a Multicenter Italian Experience.

    Science.gov (United States)

    Leon, Antonette E; Fabricio, Aline S C; Benvegnù, Fabio; Michilin, Silvia; Secco, Annamaria; Spangaro, Omar; Meo, Sabrina; Gion, Massimo

    2011-01-01

    The Nanosized Cancer Polymarker Biochip Project (RBLA03S4SP) funded by an Italian MIUR-FIRB grant (Italian Ministry of University and Research - Investment Funds for Basic Research) has led to the creation of a free-access dynamic website, available at the web address https://serviziweb.ulss12.ve.it/firbabo, and of a centralized database with password-restricted access. The project network is composed of 9 research units (RUs) and has been active since 2005. The aim of the FIRB project was the design, production and validation of optoelectronic and chemoelectronic biosensors for the simultaneous detection of a novel class of cancer biomarkers associated with immunoglobulins of the M class (IgM) for early diagnosis of cancer. Biomarker immune complexes (BM-ICs) were assessed on samples of clinical cases and matched controls for breast, colorectal, liver, ovarian and prostate malignancies. This article describes in detail the architecture of the project website, the central database application, and the biobank developed for the FIRB Nanosized Cancer Polymarker Biochip Project. The article also illustrates many unique aspects that should be considered when developing a database within a multidisciplinary scenario. The main deliverables of the project were numerous, including the development of an online database which archived 1400 case report forms (700 cases and 700 matched controls) and more than 2700 experimental results relative to the BM-ICs assayed. The database also allowed for the traceability and retrieval of 21,000 aliquots archived in the centralized bank and stored as backup in the RUs, and for the development of a centralized biological bank in the coordinating unit with 6300 aliquots of serum. The constitution of the website and biobank database enabled optimal coordination of the RUs involved, highlighting the importance of sharing samples and scientific data in a multicenter setting for the achievement of the project goals.

  7. Evaluation of heavy metals in hazardous automobile shredder residue thermal residue and immobilization with novel nano-size calcium dispersed reagent

    International Nuclear Information System (INIS)

    Lee, Chi-Hyeon; Truc, Nguyen Thi Thanh; Lee, Byeong-Kyu; Mitoma, Yoshiharu; Mallampati, Srinivasa Reddy

    2015-01-01

    Graphical abstract: Schematic representation of possible mechanisms determining the heavy metals immobilization efficiencyof ASR dust/thermal residues after treatment with nanometallic Ca/CaO/PO 4 . - Highlights: • Nanometallic Ca/CaO/PO 4 for heavy metals immobilization in ASR residue. • Heavy metals immobilization in dry condition attained about 95–100%. • Remaining heavy metals were lower than the Korean standard regulatory limit. • The amounts of heavy metals detectable on the ASR dust surface decreased. • Nanometallic Ca/CaO/PO 4 has a promising potential for heavy metal remediation. - Abstract: This study was conducted to synthesize and apply a nano-size calcium dispersed reagent as an immobilization material for heavy metal-contaminated automobile shredder residues (ASR) dust/thermal residues in dry condition. Simple mixing with a nanometallic Ca/CaO/PO 4 dispersion mixture immobilized 95–100% of heavy metals in ASR dust/thermal residues (including bottom ash, cavity ash, boiler and bag filter ash). The quantity of heavy metals leached from thermal residues after treatment by nanometallic Ca/CaO/PO 4 was lower than the Korean standard regulatory limit for hazardous waste landfills. The morphology and elemental composition of the nanometallic Ca/CaO-treated ASR residue were characterized by field emission scanning election microscopy combined with electron dispersive spectroscopy (FE-SEM/EDS). The results indicated that the amounts of heavy metals detectable on the ASR thermal residue surface decreased and the Ca/PO 4 mass percent increased. X-ray diffraction (XRD) pattern analysis indicated that the main fraction of enclosed/bound materials on ASR residue included Ca/PO 4 − associated crystalline complexes, and that immobile Ca/PO 4 salts remarkably inhibited the desorption of heavy metals from ASR residues. These results support the potential use of nanometallic Ca/CaO/PO 4 as a simple, suitable and highly efficient material for the gentle

  8. Fabrication of Hierarchically Micro- and Nano-structured Mold Surfaces Using Laser Ablation for Mass Production of Superhydrophobic Surfaces

    Science.gov (United States)

    Noh, Jiwhan; Lee, Jae-Hoon; Na, Suckjoo; Lim, Hyuneui; Jung, Dae-Hwan

    2010-10-01

    Many studies have examined the formation of surfaces with mixed patterns of micro- and nano-sized lotus leaves that have hydrophobic properties. In this study, micro- and nano-shapes such as lotus leaves were fabricated on a metal mold surface using laser ablation and ripple formation. A microstructure on the mold surface was replicated onto poly(dimethylsiloxane) (PDMS) using the polymer casting method to manufacture low-cost hydrophobic surfaces. A PDMS surface with micro- and nano-structures that were the inverse image of a lotus leaf showed hydrophobic characteristics (water contact angle: 157°). From these results, we deduced that portions of the microstructures were wet and that air gaps existed between the microstructures and the water drops. In this paper we suggest the possibility of the mass production of hydrophobic plastic surfaces and the development of a methodology for the hydrophobic texturing of various polymer surfaces, using the polymer casting method with laser-processed molds.

  9. Nano-size defects in arsenic-implanted HgCdTe films: a HRTEM study

    Science.gov (United States)

    Bonchyk, O. Yu.; Savytskyy, H. V.; Swiatek, Z.; Morgiel, Y.; Izhnin, I. I.; Voitsekhovskii, A. V.; Korotaev, A. G.; Mynbaev, K. D.; Fitsych, O. I.; Varavin, V. S.; Dvoretsky, S. A.; Marin, D. V.; Yakushev, M. V.

    2018-02-01

    Radiation damage and its transformation under annealing were studied with bright-field and high-resolution transmission electron microscopy for arsenic-implanted HgCdTe films with graded-gap surface layers. In addition to typical highly defective layers in as-implanted material, a 50 nm-thick sub-surface layer with very low defect density was observed. The main defects in other layers after implantation were dislocation loops, yet after arsenic activation annealing, the dominating defects were single dislocations. Transport (from depth to surface), transformation and annihilation of radiation-induced defects were observed as a result of annealing, with the depth with the maximum defect density decreasing from 110 to 40 nm.

  10. A high gradient and strength bioseparator with nano-sized immunomagnetic particles for specific separation and efficient concentration of E. coli O157:H7

    Science.gov (United States)

    Lin, Jianhan; Li, Min; Li, Yanbin; Chen, Qi

    2015-03-01

    Sample pretreatment is a key to rapid screening of pathogens for prevention and control of foodborne diseases. Magnetic immunoseparation is a specific method based on antibody-antigen reaction to capture the target bacteria and concentrate them in a smaller-volume buffer. The use of nano-sized magnetic particles could improve the separation efficiency of bacteria but require much higher gradient and strength magnetic field. In this study, a strong magnetic bioseparator with a mean field strength of 1.35 T and a mean gradient of 90 T/m was developed with the use of the 30 nm and 180 nm magnetic particles to specifically separate and efficiently concentrate foodborne bacterial pathogens using Escherichia coli O157:H7 as a model bacterium. The polyclonal antibodies against E. coli were evaluated using Dot ELISA analysis for their good affinity with the target bacteria and then used to modify the surface of the magnetic nanoparticles by 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC·HCl) method and streptavidin-biotin binding. The magnetic particle concentrations were optimized to be 40 μg/ml and 100 μg/ml for the 30 nm and 180 nm particles, respectively, the immunoreaction time was optimized to be 45 min for both sizes of particles, and the separation times were optimized to be 60 min and 2 min for the 30 nm and 180 nm particles, respectively. The total magnetic separation time was 2 h and 1 h for the 30 nm and 180 nm particles, respectively. The experimental results demonstrated that the bioseparator with the use of either 30 nm or 180 nm immunomagnetic particles could achieve a separation efficiency of >90% for E. coli O157:H7 at the concentrations ranging from 102 to 105 cfu/ml. No obvious interferences from non-target foodborne pathogens, such as SalmonellaTyphimurium and Listeria innocua, were found. For overall consideration of the consuming time, the cost, and the separation efficiency, the 180 nm magnetic particles are practical for rapid

  11. Dispersion of nano-sized hydrophilic silica particles into various hydrophobic polymer networks.

    Science.gov (United States)

    Tanahashi, Mitsuru; Takeda, Kunihiko

    2014-04-01

    Dispersion of fine silica particles with hydrophilic surfaces to the hydrophobic polymer network has been investigated. Strength-controlled agglomerates of silica particles with 190 nm diameter were prepared, and they were blended with some polymers in an intensive mixer. Through the shear breakdown of the silica agglomerates in the kneaded polymer melts, the isolated primary silica nanoparticles with hydrophilic surfaces were dispersed uniformly into polycarbonate, as well as poly(ethylene-ran-vinylalcohol), polystyrene, and poly(tetrafluoroethylene-co-perfluoropropylvinylether) selected as a matrix polymer in the authors' previous studies. Unexpected result was the well dispersion of the hydrophilic silica particles into hydrophobic polymers. Taking the extremely hydrophobic perfluoropolymer as an example, the reason why silica particles can disperse into a hydrophobic polymer was also discussed by comparing the quite short-range (polymer melt with that between silica nanoparticles calculated on the assumption that the agglomerate is peeling off at the shear breakdown stage. The main finding of this study is that the attractive silica-perfluoropolymer interaction may exceed the silica-silica interaction under the special condition where the perfluoropolymer chains wind about the silica surfaces in nano-areas (less than 1% of the whole surface area of the silica particle), resulting in the well dispersion of nano-silica into the perfluoropolymer.

  12. Pt supported on nanosized oxides for electrocatalyst used in polymer electrolyte fuel cells

    DEFF Research Database (Denmark)

    Banu, N.; Serban, E. C.; Marinescu, A.

    2011-01-01

    Even though Pt is a standard catalyst for fuel cells, new advanced materials with low activation energy and high specific surface area are required. Researches proved that conducting oxides are the emerging candidates as support for Pt catalysts targeting replacement of nanocarbons. This paper...

  13. Pt supported on nanosized oxides for electrocatalyst used in polymer electrolyte fuel cells

    DEFF Research Database (Denmark)

    Banu, N.; Serban, E. C.; Marinescu, A.

    2011-01-01

    Even though Pt is a standard catalyst for fuel cells, new advanced materials with low activation energy and high specific surface area are required. Researches proved that conducting oxides are the emerging candidates as support for Pt catalysts targeting replacement of nanocarbons. This paper pr...

  14. Effect of a nano-sized TiC particle addition on the flow-assisted corrosion resistance of SA 106B carbon steel

    Science.gov (United States)

    Park, Jin-Ju; Park, Eun-Kwang; Lee, Gyoung-Ja; Rhee, Chang-Kyu; Lee, Min-Ku

    2017-09-01

    Carbon steel with dispersed nano-sized TiC ceramic particles was fabricated by the ex-situ introduction of the particles into the melt, with the flow-assisted corrosion (FAC) resistance then investigated in the presence and absence of TiC nanoparticles using a once-through type of FAC loop test. From the potentiodynamic polarization curves, the current density at any given anodic potential was decreased and the open-circuit potential was increased by the addition of TiC nanoparticles. In addition, when the nano-sized TiC particles were added, the FAC rate was 1.38 times lower than that of carbon steel without TiC nanoparticles, indicating an improvement of the FAC resistance due to the homogeneous distribution of the TiC reinforcing nanoparticles.

  15. Microstructure and properties of SA 106B carbon steel after treatment of the melt with nano-sized TiC particles

    International Nuclear Information System (INIS)

    Park, Jin-Ju; Hong, Sung-Mo; Park, Eun-Kwang; Kim, Kyeong-Yeol; Lee, Min-Ku; Rhee, Chang-Kyu

    2014-01-01

    Carbon steel dispersed with nano-sized TiC ceramic particles was fabricated using the liquid metal casting process by means of their ex-situ introduction. For this purpose, the nano-sized TiC powders with an initial average size of 40 nm were first mechanically activated with two metal powders (Fe, Ni) and then introduced externally into the molten carbon steel during the casting process. According to the chemical composition analysis, 90% of the initial TiC nanoparticles were discovered within the cast carbon steel. Compared to cast carbon steel without TiC nanoparticles, the grain size refinement and mechanical property enhancement were achieved. Atom probe tomographic analysis revealed that the TiC nanoparticles were approximately 30 nm in size in the carbon steel matrix with a number density of 1.49×10 21 m −3

  16. Particle phase distribution of polycyclic aromatic hydrocarbons in stormwater — Using humic acid and iron nano-sized colloids as test particles

    DEFF Research Database (Denmark)

    Nielsen, Katrine; Kalmykova, Yuliya; Strömvall, Ann-Margret

    2015-01-01

    The distribution of polycyclic aromatic hydrocarbons (PAHs) in different particulate fractions in stormwater: Total, Particulate, Filtrated, Colloidal and Dissolved fractions, were examined and compared to synthetic suspensions of humic acid colloids and iron nano-sized particles. The distribution...... to a higher extent in the Filtrated fractions. The highest concentrations of PAHs were present in the stormwater with the highest total suspended solids (TSS); the relative amount of the HMWPAHs was highest in the Particulate fractions (particles N 0.7 μm). The highest concentration of PAHs in the Colloidal...... fraction was found in the sample with occurrence of small nano-sized particles (b10 nm). The results show the importance of developing technologies that both can manage particulate matter and effectively remove PAHs present in the Colloidal and Dissolved fractions in stormwater. © 2015 Elsevier B.V. All...

  17. Strategy for chemotherapeutic delivery using a nanosized porous metal-organic framework with a central composite design

    Directory of Open Access Journals (Sweden)

    Li YP

    2017-02-01

    Full Text Available Yingpeng Li,1 Xiuyan Li,2 Qingxia Guan,2 Chunjing Zhang,2 Ting Xu,2 Yujing Dong,2 Xinyu Bai,2 Weiping Zhang3 1College of Pharmacy, Tianjin University of Traditional Chinese Medicine, Tianjin, 2College of Pharmacy, Heilongjiang University of Traditional Chinese Medicine, Harbin, People’s Republic of China; 3Pope John XXIII High School, Everett, MA, USA Background: Enhancing drug delivery is an ongoing endeavor in pharmaceutics, especially when the efficacy of chemotherapy for cancer is concerned. In this study, we prepared and evaluated nanosized HKUST-1 (nanoHKUST-1, nanosized metal-organic drug delivery framework, loaded with 5-fluorouracil (5-FU for potential use in cancer treatment.Materials and methods: NanoHKUST-1 was prepared by reacting copper (II acetate [Cu(OAc2] and benzene-1,3,5-tricarboxylic acid (H3BTC with benzoic acid (C6H5COOH at room temperature (23.7°C±2.4°C. A central composite design was used to optimize 5-FU-loaded nanoHKUST-1. Contact time, ethanol concentration, and 5-FU:material ratios were the independent variables, and the entrapment efficiency of 5-FU was the response parameter measured. Powder X-ray diffraction, scanning electron microscopy (SEM, transmission electron microscopy (TEM, and nitrogen adsorption were used to determine the morphology of nanoHKUST-1. In addition, 5-FU release studies were conducted, and the in vitro cytotoxicity was evaluated.Results: Entrapment efficiency and drug loading were 9.96% and 40.22%, respectively, while the small-angle X-ray diffraction patterns confirmed a regular porous structure. The SEM and TEM images of the nanoHKUST-1 confirmed the presence of round particles (diameter: approximately 100 nm and regular polygon arrays of mesoporous channels of approximately 2–5 nm. The half-maximal lethal concentration (LC50 of the 5-FU-loaded nanoHKUST-1 was approximately 10 µg/mL.Conclusion: The results indicated that nanoHKUST-1 is a potential vector worth developing as a

  18. Preparation and characterization of nano-sized phase change emulsions as thermal energy storage and transport media

    International Nuclear Information System (INIS)

    Chen, J.; Zhang, P.

    2017-01-01

    Highlights: • The nano-sized phase change emulsions are prepared by using D-phase method. • The thermo-physical and transport properties are experimentally investigated. • The influence of surfactant on the melting temperature and latent heat of water is clarified. • The phase change emulsion can be used as the heat transfer fluid in a thermal energy storage system. - Abstract: Phase change emulsion (PCE) is a kind of two-phase heat transfer fluid with phase change material (PCM) dispersed in carrier fluid. It has received intensive attractions in recent years due to the fact that it can be used as both the thermal energy storage material and transport medium simultaneously in a thermal energy storage system. In the present study, nano-sized PCEs are prepared by the D-phase method with n-hexadecane and n-octadecane as PCMs. The thermo-physical and transport properties are characterized to facilitate the applications. The droplet size distribution of the PCE is measured by a Photon Correlation Spectroscopy, and the results show that the droplet size distributions are similar at different mass fractions. The rheological behavior and viscosity of the PCE are measured by a rheometer, which shows that the PCEs at mass fractions below 30.0 wt% are Newtonian fluids, and the viscosities are dependent on both the mass fraction and temperature. The differential scanning calorimetry (DSC) is employed to analyze the phase change characteristics of the PCE, and the results indicate large supercooling degree of water and PCM in the PCE. The melting temperature and latent heat of water in the PCE are much smaller than those of pure water. The thermal conductivities of the PCE with different mass fractions at different temperatures are measured by the transient hot-wire method. Furthermore, the energy transport characteristics of the PCEs are evaluated on the basis of the measured thermo-physical and transport properties. The results suggest that the PCEs show a drastic

  19. Nanosized Magnesium Electrochemically Deposited on a Carbon Nanotubes Suspension: Synthesis and Hydrogen Storage

    Directory of Open Access Journals (Sweden)

    Chaoqi Shen

    2017-10-01

    Full Text Available Herein, we report on a novel method for deposition of magnesium (Mg nanoparticles at the surface of carbon materials. Through the suspension of carbon nanotubes (CNTs in an electrolyte containing di-n-butylmagnesium as a precursor, Mg nanoparticles were effectively deposited at the surface of the CNTs as soon as these touched the working electrode. Through this process, CNTs supported Mg particles as small as 1 nm were synthesized and the distribution of the nanoparticles was found to be influenced by the concentration of the CNTs in the electrolyte. Hydrogenation of these nanoparticles at 100°C was found to lead to low temperature hydrogen release starting at 150°C, owing to shorter diffusion paths and higher hydrogen mobility in small Mg particles. However, these hydrogen properties drastically degraded as soon as the hydrogenation temperature exceeded 200°C and this may be related to the low melting temperature of ultrasmall Mg particles.

  20. Nanosized Magnesium Electrochemically Deposited on a Carbon Nanotubes Suspension: Synthesis and Hydrogen Storage

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Chaoqi; Aguey-Zinsou, Kondo-Francois, E-mail: f.aguey@unsw.edu.au [MERLin, School of Chemical Engineering, The University of New South Wales, Sydney, NSW (Australia)

    2017-10-17

    Herein, we report on a novel method for deposition of magnesium (Mg) nanoparticles at the surface of carbon materials. Through the suspension of carbon nanotubes (CNTs) in an electrolyte containing di-n-butylmagnesium as a precursor, Mg nanoparticles were effectively deposited at the surface of the CNTs as soon as these touched the working electrode. Through this process, CNTs supported Mg particles as small as 1 nm were synthesized and the distribution of the nanoparticles was found to be influenced by the concentration of the CNTs in the electrolyte. Hydrogenation of these nanoparticles at 100°C was found to lead to low temperature hydrogen release starting at 150°C, owing to shorter diffusion paths and higher hydrogen mobility in small Mg particles. However, these hydrogen properties drastically degraded as soon as the hydrogenation temperature exceeded 200°C and this may be related to the low melting temperature of ultrasmall Mg particles.

  1. Nanosized silver?anionic clay matrix as nanostructured ensembles with antimicrobial activity

    OpenAIRE

    2009-01-01

    Abstract Nanostructured ensembles of silver nanoparticles/zinc-substituted anionic clay matrix (Ag/ZnLDH) were obtained by a simple synthetic route in which reconstruction of the layered clay, synthesis of the silver nanoparticles and their organisation on the clay surface took place in a single step at room temperature. The morphology, composition and phase structure of the prepared powders were characterised by X-ray diffraction, infrared spectroscopy, transmission electron micro...

  2. High Relaxivity Gadolinium Hydroxypyridonate-Viral Capsid Conjugates: Nano-sized MRI Contrast Agents

    Energy Technology Data Exchange (ETDEWEB)

    Meux, Susan C.; Datta, Ankona; Hooker, Jacob M.; Botta, Mauro; Francis, Matthew B.; Aime, Silvio; Raymond, Kenneth N.

    2007-08-29

    High relaxivity macromolecular contrast agents based on the conjugation of gadolinium chelates to the interior and exterior surfaces of MS2 viral capsids are assessed. The proton nuclear magnetic relaxation dispersion (NMRD) profiles of the conjugates show up to a five-fold increase in relaxivity, leading to a peak relaxivity (per Gd{sup 3+} ion) of 41.6 mM{sup -1}s{sup -1} at 30 MHz for the internally modified capsids. Modification of the exterior was achieved through conjugation to flexible lysines, while internal modification was accomplished by conjugation to relatively rigid tyrosines. Higher relaxivities were obtained for the internally modified capsids, showing that (1) there is facile diffusion of water to the interior of capsids and (2) the rigidity of the linker attaching the complex to the macromolecule is important for obtaining high relaxivity enhancements. The viral capsid conjugated gadolinium hydroxypyridonate complexes appear to possess two inner-sphere water molecules (q = 2) and the NMRD fittings highlight the differences in the local motion for the internal ({tau}{sub RI} = 440 ps) and external ({tau}{sub RI} = 310 ps) conjugates. These results indicate that there are significant advantages of using the internal surface of the capsids for contrast agent attachment, leaving the exterior surface available for the installation of tissue targeting groups.

  3. Carbon cryogel as support of platinum nano-sized electrocatalyst for the hydrogen oxidation reaction

    International Nuclear Information System (INIS)

    Babic, B.M.; Vracar, Lj.M.; Radmilovic, V.; Krstajic, N.V.

    2006-01-01

    The kinetics of hydrogen oxidation reaction was studied in perchloric acid solution on carbon-supported Pt nanoparticles using the rotating disk electrode technique. Carbon cryogel and commercial carbon black. Vulcan XC-72 were used as catalyst supports. Pt/C catalysts were prepared by a modified polyol synthesis method in an ethylene glycol (EG) solution. Considerable effect has been observed for the specific surface area of carbon support on the fundamental properties of Pt/C catalyst, such as catalyst particle size distribution and dispersion as well as catalytic activity for the oxidation of hydrogen. X-ray diffraction (XRD) and transmission electron microscopy (TEM) images show that the particle size of the catalyst decreases with the increase of specific surface area of carbon support. Cyclic voltammetry (CV) was used for determination of the actual exposed surface area of catalyst particles. It was found that Pt catalyst prepared by using the novel carbon material displayed better hydrogen electrochemical oxidation activity than the catalyst prepared by using Vulcan XC-72

  4. Effect of nano-size oxide particle dispersion and δ-ferrite proportion on creep strength of 9Cr-ODS steel

    International Nuclear Information System (INIS)

    Ohtsuka, Satoshi; Kaito, Takeji; Kim, Sawoong; Inoue, Masaki; Asayama, Tai; Ohnuma, Masato; Suzuki, Junichi

    2009-01-01

    The effects of chemical compositions on the microstructure and high-temperature creep strength of 9Cr-ODS steel was discussed in the light of quantitative data of δ-ferrite proportion and nano-size oxide particle dispersion, which were evaluated by dilatometric analysis and small angle neutron/X-ray scattering analysis, respectively. These quantitative data are well consistent with the conventional data obtained by transmission electron microscope. Both data indicate that the important microstructural feature for creep strength improvement of the 9Cr-ODS steel is the number density of nano-size oxide particles, and ferrite/martensite (F/M) duplex structure is favorable for high population nano-size oxide particle dispersion. Both optimization of excess oxygen concentration and control of the F/M duplex structure are promising technique for nano-structure control of 9Cr-ODS steel. Tungsten solid solution strengthening appears to be small compared with oxide dispersion strengthening enhanced by duplex microstructure formation. (author)

  5. The use of nano-sized eggshell powder for calcium fortification of cow?s and buffalo?s milk yogurts.

    Science.gov (United States)

    El-Shibiny, Safinaze; El-Gawad, Mona Abd El-Kader Mohamed Abd; Assem, Fayza Mohamed; El-Sayed, Samah Mosbah

    2018-01-01

    Calcium is an essential element for the growth, activity, and maintenance of the human body. Eggshells are a waste product which has received growing interest as a cheap and effective source of dietary calcium. Yogurt is a food which can be fortified with functional additives, including calcium. The aim of this study was to produce yogurt with a high calcium content by fortification with nano-sized eggshell powder (nano-ESP). Nano-sized ESP was prepared from pre-boiled and dried eggshell, using a ball mill. Yogurt was prepared from cow’s milk supplemented with 3% skimmed milk powder, and from buffalo’s milk fortified with 0.1, 0.2 and 0.3% and 0.1, 0.3 and 0.5% nano-ESP respectively. Electron microscopic transmission showed that the powder consisted of nano-sized crystalline struc- tures (~10 nm). Laser scattering showed that particles followed a normal distribution pattern with z-average of 590.5 nm, and had negative zeta-potential of –9.33 ±4.2 mV. Results regarding changes in yogurt composi- tion, acid development, calcium distribution, biochemical changes, textural parameters and sensory attributes have been presented and discussed. The addition of up to 0.3% nano-ESP made cow and buffalo high-calcium yogurts with an acceptable composition and quality. High-calcium yogurt may offer better health benefits, such as combating osteoporosis.

  6. Exposure to nano-size titanium dioxide causes oxidative damages in human mesothelial cells: The crystal form rather than size of particle contributes to cytotoxicity.

    Science.gov (United States)

    Hattori, Kenji; Nakadate, Kazuhiko; Morii, Akane; Noguchi, Takumi; Ogasawara, Yuki; Ishii, Kazuyuki

    2017-10-14

    Exposure to nanoparticles such as carbon nanotubes has been shown to cause pleural mesothelioma similar to that caused by asbestos, and has become an environmental health issue. Not only is the percutaneous absorption of nano-size titanium dioxide particles frequently considered problematic, but the possibility of absorption into the body through the pulmonary route is also a concern. Nevertheless, there are few reports of nano-size titanium dioxide particles on respiratory organ exposure and dynamics or on the mechanism of toxicity. In this study, we focused on the morphology as well as the size of titanium dioxide particles. In comparing the effects between nano-size anatase and rutile titanium dioxide on human-derived pleural mesothelial cells, the anatase form was shown to be actively absorbed into cells, producing reactive oxygen species and causing oxidative damage to DNA. In contrast, we showed for the first time that the rutile form is not easily absorbed by cells and, therefore, does not cause oxidative DNA damage and is significantly less damaging to cells. These results suggest that with respect to the toxicity of titanium dioxide particles on human-derived mesothelial cells, the crystal form rather than the particle size has a greater effect on cellular absorption. Also, it was indicated that the difference in absorption is the primary cause of the difference in the toxicity against mesothelial cells. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Preparation of Nano-sized Bismuth-Doped Fe3O4 as an Excellent Magnetic Material for Supercapacitor Electrodes

    Science.gov (United States)

    Aghazadeh, Mustafa; Karimzadeh, Isa; Ganjali, Mohammad Reza

    2018-03-01

    Nano-sized Bi3+-doped iron oxide (n-Bi-IO) particles were prepared through a one-pot electrochemical procedure, and the product was evaluated using x-ray diffraction, field-emission scanning electron microscopy and energy-dispersive x-ray spectroscopy. Based on the analyses, the average size of the n-Bi-IO was determined to be 10 nm. Galvanostatic charge-discharge (GCD) evaluations revealed that the specific capacitance of the material reached 235 F g-1 at a discharge condition of 0.2 A g-1. n-Bi-IO had a 94.2% capacity retention after 2000 GCD cycles. Further vibrating sample magnetometery analyses showed that the product has enhanced superparamagnetic qualities (i.e. M r = 0.15 emu g-1 and H Ci = 2.71 G) in comparison to iron oxide nanoparticles (i.e. M r = 0.95 emu g-1 and H Ci = 14.62 G). Given the results, the product is considered to be a promising material for developing high performance supercapacitor electrodes.

  8. Design and formulation of nano-sized spray dried efavirenz-part I: influence of formulation parameters

    International Nuclear Information System (INIS)

    Katata, Lebogang; Tshweu, Lesego; Naidoo, Saloshnee; Kalombo, Lonji; Swai, Hulda

    2012-01-01

    Efavirenz (EFV) is one of the first-line antiretroviral drugs recommended by the World Health Organisation for treating HIV. It is a hydrophobic drug that suffers from low aqueous solubility (4 μg/mL), which leads to a limited oral absorption and low bioavailability. In order to improve its oral bioavailability, nano-sized polymeric delivery systems are suggested. Spray dried polycaprolactone-efavirenz (PCL-EFV) nanoparticles were prepared by the double emulsion method. The Taguchi method, a statistical design with an L 8 orthogonal array, was implemented to optimise the formulation parameters of PCL-EFV nanoparticles. The types of sugar (lactose or trehalose), surfactant concentration and solvent (dichloromethane and ethyl acetate) were chosen as significant parameters affecting the particle size and polydispersity index (PDI). Small nanoparticles with an average particle size of less than 254 ± 0.95 nm in the case of ethyl acetate as organic solvent were obtained as compared to more than 360 ± 19.96 nm for dichloromethane. In this study, the type of solvent and sugar were the most influencing parameters of the particle size and PDI. Taguchi method proved to be a quick, valuable tool in optimising the particle size and PDI of PCL-EFV nanoparticles. The optimised experimental values for the nanoparticle size and PDI were 217 ± 2.48 nm and 0.093 ± 0.02.

  9. Design and formulation of nano-sized spray dried efavirenz-part I: influence of formulation parameters

    Energy Technology Data Exchange (ETDEWEB)

    Katata, Lebogang, E-mail: lebzakate@yahoo.com; Tshweu, Lesego; Naidoo, Saloshnee; Kalombo, Lonji; Swai, Hulda [Materials Science and Manufacturing, Centre of Polymers and Composites, Council for Scientific and Industrial Research (South Africa)

    2012-11-15

    Efavirenz (EFV) is one of the first-line antiretroviral drugs recommended by the World Health Organisation for treating HIV. It is a hydrophobic drug that suffers from low aqueous solubility (4 {mu}g/mL), which leads to a limited oral absorption and low bioavailability. In order to improve its oral bioavailability, nano-sized polymeric delivery systems are suggested. Spray dried polycaprolactone-efavirenz (PCL-EFV) nanoparticles were prepared by the double emulsion method. The Taguchi method, a statistical design with an L{sub 8} orthogonal array, was implemented to optimise the formulation parameters of PCL-EFV nanoparticles. The types of sugar (lactose or trehalose), surfactant concentration and solvent (dichloromethane and ethyl acetate) were chosen as significant parameters affecting the particle size and polydispersity index (PDI). Small nanoparticles with an average particle size of less than 254 {+-} 0.95 nm in the case of ethyl acetate as organic solvent were obtained as compared to more than 360 {+-} 19.96 nm for dichloromethane. In this study, the type of solvent and sugar were the most influencing parameters of the particle size and PDI. Taguchi method proved to be a quick, valuable tool in optimising the particle size and PDI of PCL-EFV nanoparticles. The optimised experimental values for the nanoparticle size and PDI were 217 {+-} 2.48 nm and 0.093 {+-} 0.02.

  10. Huge Inverse Magnetization Generated by Faraday Induction in Nano-Sized Au@Ni Core@Shell Nanoparticles

    Directory of Open Access Journals (Sweden)

    Chen-Chen Kuo

    2015-08-01

    Full Text Available We report on the design and observation of huge inverse magnetizations pointing in the direction opposite to the applied magnetic field, induced in nano-sized amorphous Ni shells deposited on crystalline Au nanoparticles by turning the applied magnetic field off. The magnitude of the induced inverse magnetization is very sensitive to the field reduction rate as well as to the thermal and field processes before turning the magnetic field off, and can be as high as 54% of the magnetization prior to cutting off the applied magnetic field. Memory effect of the induced inverse magnetization is clearly revealed in the relaxation measurements. The relaxation of the inverse magnetization can be described by an exponential decay profile, with a critical exponent that can be effectively tuned by the wait time right after reaching the designated temperature and before the applied magnetic field is turned off. The key to these effects is to have the induced eddy current running beneath the amorphous Ni shells through Faraday induction.

  11. A nanosized Ag–silica hybrid complex prepared by γ-irradiation activates the defense response in Arabidopsis

    International Nuclear Information System (INIS)

    Chu, Hyosub; Kim, Hwa-Jung; Su Kim, Joong; Kim, Min-Soo; Yoon, Byung-Dae; Park, Hae-Jun; Kim, Cha Young

    2012-01-01

    Silver nanoparticles have antimicrobial activity against many pathogenic microbes. Here, the preparation of a nanosized Ag–silica hybrid complex (NSS) prepared by γ-irradiation is described. The effects of both NSS and reduced Ag nanoparticles (Ag 0 ) on the growth of the model plant Arabidopsis thaliana were tested. The application of 1–10 ppm NSS complex improved Arabidopsis growth in soil, whereas 100 ppm NSS resulted in weakly curled leaves. In addition, supplementation of Murashige and Skoog (MS) growth medium with 1 ppm NSS promoted the root growth of Arabidopsis seedlings, but root growth was inhibited by supplementation with 10 ppm NSS. To investigate whether the NSS complex could induce plant defense responses, the expression of pathogenesis-related (PR) genes that are implicated in systemic acquired resistance (SAR) in Arabidopsis plants was examined. PR1, PR2 and PR5 were significantly up-regulated by each application of 10 ppm NSS complex or Ag 0 to the rosette leaves. Furthermore, pretreatment with the NSS complex induced more pathogen resistance to the virulent pathogen Pseudomonas syringae pv. tomato DC3000 (Pst) compared to water treatment in Arabidopsis plants. - Research highlights: ► We describe the preparation of silver nanoparticles using γ-irradiation technique. ► We examine the effects of silver nanoparticles on the growth of Arabidopsis. ► Silver nanoparticles induced the expression of SAR marker genes. ► Silver nanoparticles exhibited enhanced disease resistance to the bacterial pathogen.

  12. A nanosized Ag-silica hybrid complex prepared by γ-irradiation activates the defense response in Arabidopsis

    Science.gov (United States)

    Chu, Hyosub; Kim, Hwa-Jung; Su Kim, Joong; Kim, Min-Soo; Yoon, Byung-Dae; Park, Hae-Jun; Kim, Cha Young

    2012-02-01

    Silver nanoparticles have antimicrobial activity against many pathogenic microbes. Here, the preparation of a nanosized Ag-silica hybrid complex (NSS) prepared by γ-irradiation is described. The effects of both NSS and reduced Ag nanoparticles (Ag 0) on the growth of the model plant Arabidopsis thaliana were tested. The application of 1-10 ppm NSS complex improved Arabidopsis growth in soil, whereas 100 ppm NSS resulted in weakly curled leaves. In addition, supplementation of Murashige and Skoog (MS) growth medium with 1 ppm NSS promoted the root growth of Arabidopsis seedlings, but root growth was inhibited by supplementation with 10 ppm NSS. To investigate whether the NSS complex could induce plant defense responses, the expression of pathogenesis-related ( PR) genes that are implicated in systemic acquired resistance (SAR) in Arabidopsis plants was examined. PR1, PR2 and PR5 were significantly up-regulated by each application of 10 ppm NSS complex or Ag 0 to the rosette leaves. Furthermore, pretreatment with the NSS complex induced more pathogen resistance to the virulent pathogen Pseudomonas syringae pv. tomato DC3000 ( Pst) compared to water treatment in Arabidopsis plants.

  13. Characterization of coke deposited on nano-sized Pt-Pd/H-beta spent during long-chain paraffin hydroisomerization

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, F.; Einicke, W.D.; Ficht, K.; Glaeser, R. [Leipzig Univ. (Germany). Inst. of Chemical Technology; Bertmer, M. [Leipzig Univ. (Germany). Inst. of Experimental Physics II; Kuchling, T. [Technische Univ. Bergakademie Freiberg (Germany). Inst. of Energy Process Engineering and Chemical Engineering

    2013-11-01

    The hydroisomerization of long-chain n-paraffins were studied in the temperature range 205- 230 C at p{sub H2}=50 bar using a bench scale trickle-bed continuous-flow reactor. The bimetallic catalysts consisted of mixtures of platinum and palladium supported on commercially available nano-sized zeolites Beta (n{sub Si}/n{sub Al} = 12 and 25) extruded with a binder ({gamma}-alumina). For hexadecane conversion, high yields to isomers (25 and 45 wt.% of mono- and multibranched isomers, respectively) without extensive cracking (>10 wt.%) were obtained at a conversion of 80 %. Long-term tests with C{sub 16}H{sub 34} and blends of solid n-paraffins for 30-60 days on stream clearly indicate that a minor loss in catalyst activity can easily be compensated by increasing the reaction temperature from 230 C to 235 C. The zeolite sample with a 'mild acidity' revealed low hydrocracking at isomerization yield up to 70 wt.% and high stability. Carbonaceous deposits formed during n-paraffin hydroisomerization were investigated by temperature-programmed oxidation, elemental analysis, ATR-FTIR and {sup 13}C MAS NMR spectroscopy showing the formation of low-temperature, hydrogen-rich coke. (orig.)

  14. Exploiting the nano-sized features of microfibrillated cellulose (MFC) for the development of controlled-release packaging.

    Science.gov (United States)

    Cozzolino, Carlo A; Nilsson, Fritjof; Iotti, Marco; Sacchi, Benedetta; Piga, Antonio; Farris, Stefano

    2013-10-01

    Microfibrillated cellulose (MFC) was used in this study to prepare films containing an active molecule, lysozyme, which is a natural antimicrobial agent. The main goal of this research was to assess the potential for exploiting the nano-sized dimension of cellulose fibrils to slow the release of the antimicrobial molecule, thus avoiding a too-quick release into the surrounding medium, which is a major disadvantage of most release systems. For this purpose, the release kinetics of lysozyme over a 10-day period in two different media (pure water and water/ethanol 10wt.%) were obtained, and the experimental data was fitted with a solution of Fick's second law to quantify the apparent diffusion coefficient (D). The results indicate that the MFC retained lysozyme, presumably due to electrostatic, hydrogen, and ion-dipole interactions, with the largest release of lysozyme-approximately 14%-occurring from the initial amount loaded on the films. As expected, ethanol as a co-solvent slightly decreased the diffusion of lysozyme from the MFC polymer network. The addition of two potential modulating release agents-glycerol and sodium chloride-was also evaluated. Findings from this work suggest that MFC-based films can be considered a suitable candidate for use in controlled-release packaging systems. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. The way to cover prediction for cytotoxicity for all existing nano-sized metal oxides by using neural network method.

    Science.gov (United States)

    Fjodorova, Natalja; Novic, Marjana; Gajewicz, Agnieszka; Rasulev, Bakhtiyor

    2017-05-01

    The regulatory agencies should fulfil the data gap in toxicity for new chemicals including nano-sized compounds, like metal oxides nanoparticles (MeO x NPs) according to the registration, evaluation, authorisation and restriction of chemicals (REACH) legislation policy. This study demonstrates the perspective capability of neural network models for prediction of cytotoxicity of MeO x NPs to bacteria Escherichia coli (E. coli) for the widest range of metal oxides extracted from Periodic table. The counter propagation artificial neural network (CP ANN) models for prediction of cytotoxicity of MeO x NPs for data sets of 17, 36 and 72 metal oxides were employed in the study. The cytotoxicity of studied metal oxide NPs was correlated with (i) χ-metal electronegativity (EN) by Pauling scale and composition of metal oxides characterised by (ii) number of metal atoms in oxide, (iii) number of oxygen atoms in oxide and (iv) charge of metal cation in oxide. The paper describes the models in context of five OECD principles of validation models accepted for regulatory use. The recommendations were done for the minimal number of cytotoxicity tests needs for evaluation of the large set of MeO x with different oxidation states. The methodology is expected to be useful for potential hazard assessment of MeO x NPs and prioritisation for further testing and risk assessment.

  16. Thermo-stabilized, porous polyimide microspheres prepared from nanosized SiO2 templating via in situ polymerization

    Directory of Open Access Journals (Sweden)

    M. Q. Liu

    2015-01-01

    Full Text Available In this article, we addressed a feasible and versatile method of the fabrication of porous polyimide microspheres presenting excellent heat resistance. The preparation process consisted of two steps. Firstly, a novel polyimide/nano-silica composite microsphere was prepared via the self-assembly structures of poly(amic acid (PAA, precursor of PI/nanosized SiO2 blends after in situ polymerization, following the two-steps imidization. Subsequently, the encapsulated nanoparticles were etched away by hydrofluoric acid treatment, giving rise to the pores. It is found the composite structure of PI/SiO2 is a precondition of the formation of nanoporous structures, furthermore, the morphology of the resultant pore could be relatively tuned by changing the content and initial morphology of silica nano-particles trapped into PI matrix. The thermal properties of the synthesized PI porous spheres were studied, indicating that the introduction of nanopores could not effectively influence the thermal stabilities of PI microspheres. Moreover, the fabrication technique described here may be extended to other porous polymer systems.

  17. Nano-sized structured layered positive electrode materials to enable high energy density and high rate capability lithium batteries

    Science.gov (United States)

    Deng, Haixia; Belharouak, Ilias; Amine, Khalil

    2012-10-02

    Nano-sized structured dense and spherical layered positive active materials provide high energy density and high rate capability electrodes in lithium-ion batteries. Such materials are spherical second particles made from agglomerated primary particles that are Li.sub.1+.alpha.(Ni.sub.xCo.sub.yMn.sub.z).sub.1-tM.sub.tO.sub.2-dR.sub.d- , where M is selected from can be Al, Mg, Fe, Cu, Zn, Cr, Ag, Ca, Na, K, In, Ga, Ge, V, Mo, Nb, Si, Ti, Zr, or a mixture of any two or more thereof, R is selected from F, Cl, Br, I, H, S, N, or a mixture of any two or more thereof, and 0.ltoreq..alpha..ltoreq.0.50; 0

  18. Artificial biomelanin: highly light-absorbing nano-sized eumelanin by biomimetic synthesis in chicken egg white.

    Science.gov (United States)

    della Vecchia, Nicola Fyodor; Cerruti, Pierfrancesco; Gentile, Gennaro; Errico, Maria Emanuela; Ambrogi, Veronica; D'Errico, Gerardino; Longobardi, Sara; Napolitano, Alessandra; Paduano, Luigi; Carfagna, Cosimo; d'Ischia, Marco

    2014-10-13

    The spontaneous oxidative polymerization of 0.01-1% w/w 5,6-dihydroxyindole (DHI) in chicken egg white (CEW) in the absence of added solvents leads to a black, water-soluble, and processable artificial biomelanin (ABM) with robust and 1 order of magnitude stronger broadband light absorption compared to natural and synthetic eumelanin suspensions. Small angle neutron scattering (SANS) and transmission electron microscopy (TEM) analysis indicated the presence in the ABM matrix of isolated eumelanin nanoparticles (≤100 nm) differing in shape from pure DHI melanin nanoparticles (SANS evidence). Electron paramagnetic resonance (EPR) spectra showed a slightly asymmetric signal (g ∼ 2.0035) similar to that of solid DHI melanin but with a smaller amplitude (ΔB), suggesting hindered spin delocalization in biomatrix. Enhanced light absorption, altered nanoparticle morphology and decreased free radical delocalization in ABM would reflect CEW-induced inhibition of eumelanin aggregation during polymerization accompanied in part by covalent binding of growing polymer to the proteins (SDS-PAGE evidence). The technological potential of eumelanin nanosizing by biomimetic synthesis within a CEW biomatrix is demonstrated by the preparation of an ABM-based black flexible film with characteristics comparable to those of commercially available polymers typically used in electronics and biomedical applications.

  19. Disperse dyeing and antibacterial properties of nylon and wool fibers using two novel nanosized copper(II complexes bearing phosphoramide

    Directory of Open Access Journals (Sweden)

    Zahra Shariatinia

    2017-11-01

    Full Text Available Disperse dyeing of nylon and wool fibers with two new nanosized copper(II complexes including phosphoric triamide ligands with formula Cu(NO32L2 (1 and Cu(CH3COO2L2 (2 where L = 4-NO2C6H4NHP(O(NC4H8O2 (A was performed successfully. Both complexes 1 and 2 produced yellow and green colored nylon and wool fabrics, respectively. The complexes were synthesized by ultrasonic method and characterized by 1H, 13C, 31P NMR, Fourier-transform infrared, photoluminescence, ultraviolet–visible spectroscopy, X-ray diffraction, field-emission microscopy and elemental analysis. The FE-SEM micrographs revealed that the nanoparticles of these compounds are spherical in morphology and ∼17–20 nm in size. Very appropriate washfastness while poor lightfastness results were deduced for the dyed fibers. The in vitro antibacterial activities of the dyes 1, 2 and dyed wool/nylon fibers against the Gram-positive Bacillus subtilis bacterium illustrated increasing in the antibacterial effect by increasing the dye concentration from 0.1% to 0.5% o.w.f. on both wool and nylon dyed fibers.

  20. Magnetic and thermodynamic properties of nanosized Zn ferrite with normal spinal structure synthesized using a facile method.

    Science.gov (United States)

    Zhang, Yunong; Shi, Quan; Schliesser, Jacob; Woodfield, Brian F; Nan, Zhaodong

    2014-10-06

    Normal spinel zinc ferrite (ZnFe2O4) nanoparticles (NPs) with zero net magnetization were synthesized by a facile coprecipitation method in which two kinds of organic alkali, namely, 1-amino-2-propanol (MIPA) and bis(2-hydroxypropyl)-amine (DIPA), were used. The diameters of the ZnFe2O4 NPs were determined to be about 7 and 9 nm for samples prepared with MIPA and DIPA, respectively, and the normal spinel structure was confirmed by the magnetic property measurement at room temperature and the temperature dependence of the direct current magnetization. These results are different from those reported in the literature, where ZnFe2O4 NPs show a nonzero net magnetization. The heat capacity of the ZnFe2O4 NPs synthesized using DIPA was measured using a physical property measurement system in the temperature range from 2 to 300 K, and the thermodynamic functions were calculated based on the curve fitting of the experimental heat capacity data. The heat capacity of the ZnFe2O4 NPs was compared with that of a nanosized (Zn(0.795)Fe(0.205))[Zn(0.205)Fe(1.795)]O4 material studied in the literature, indicating that the Debye temperature of the present sample is more comparable with that of the bulk ZnFe2O4 reported by Westrum et al.

  1. Genotoxicity evaluation of nanosized titanium dioxide, synthetic amorphous silica and multi-walled carbon nanotubes in human lymphocytes.

    Science.gov (United States)

    Tavares, Ana M; Louro, Henriqueta; Antunes, Susana; Quarré, Stephanie; Simar, Sophie; De Temmerman, Pieter-Jan; Verleysen, Eveline; Mast, Jan; Jensen, Keld A; Norppa, Hannu; Nesslany, Fabrice; Silva, Maria João

    2014-02-01

    Toxicological characterization of manufactured nanomaterials (NMs) is essential for safety assessment, while keeping pace with innovation from their development and application in consumer products. The specific physicochemical properties of NMs, including size and morphology, might influence their toxicity and have impact on human health. The present work aimed to evaluate the genotoxicity of nanosized titanium dioxide (TiO2), synthetic amorphous silica (SAS) and multiwalled carbon nanotubes (MWCNTs), in human lymphocytes. The morphology and size of those NMs were characterized by transmission electron microscopy, while the hydrodynamic particle size-distributions were determined by dynamic light scattering. Using a standardized procedure to ensure the dispersion of the NMs and the cytokinesis-block micronucleus assay (without metabolic activation), we observed significant increases in the frequencies of micronucleated binucleated cells (MNBCs) for some TiO2 NMs and for two MWCNTs, although no clear dose-response relationships could be disclosed. In contrast, all forms of SAS analyzed in this study were unable to induce micronuclei. The present findings increase the weight of evidence towards a genotoxic effect of some forms of TiO2 and some MWCNTs. Regarding safety assessment, the differential genotoxicity observed for closely related NMs highlights the importance of investigating the toxic potential of each NM individually, instead of assuming a common mechanism and equal genotoxic effects for a set of similar NMs. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Mobility of nanosized cerium dioxide and polymeric capsules in quartz and loamy sands saturated with model and natural groundwaters.

    Science.gov (United States)

    Petosa, Adamo Riccardo; Ohl, Carolin; Rajput, Faraz; Tufenkji, Nathalie

    2013-10-01

    The environmental and health risks posed by emerging engineered nanoparticles (ENPs) released into aquatic environments are largely dependent on their aggregation, transport, and deposition behavior. Herein, laboratory-scale columns were used to examine the mobility of polyacrylic acid (PAA)-coated cerium dioxide nanoparticles (nCeO2) and an analogous nanosized polymeric capsule (nCAP) in water saturated quartz sand or loamy sand. The influence of solution ionic strength (IS) and cation type (Na(+), Ca(2+), or Mg(2+)) on the transport potential of these ENPs was examined in both granular matrices and results were also compared to measurements obtained using a natural groundwater. ENP suspensions were characterized using dynamic light scattering and nanoparticle tracking analysis to establish aggregate size, and laser Doppler electrophoresis to determine ENP electrophoretic mobility. Regardless of IS, virtually all nCeO2 particles suspended in NaNO3 eluted from the quartz sand-packed columns. In contrast, heightened nCeO2 and nCAP particle retention and dynamic (time-dependent) transport behavior was observed with increasing concentrations of the divalent salts and in the presence of natural groundwater. Enhanced particle retention was also observed in loamy sand in comparison to the quartz sand, emphasizing the need to consider the nature of the aqueous matrix and granular medium in evaluating contamination risks associated with the release of ENPs in natural and engineered aquatic environments. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Thermal annealing behavior of nano-size metal-oxide particles synthesized by ion implantation in Fe-Cr alloy

    Science.gov (United States)

    Zheng, C.; Gentils, A.; Ribis, J.; Borodin, V. A.; Descoins, M.; Mangelinck, D.; Dalle, F.; Arnal, B.; Delauche, L.

    2017-05-01

    Oxide dispersion strengthened (ODS) steels are promising structural materials for the next generation nuclear reactors, as well as fusion facilities. The detailed understanding of the mechanisms involved in the precipitation of nano-oxides during ODS steel production would strongly contribute to the improvement of the mechanical properties and the optimization of manufacturing of ODS steels, with a potentially strong economic impact for their industrialization. A useful tool for the experimental study of nano-oxide precipitation is ion implantation, a technique that is widely used to synthesize precipitate nanostructures in well-controlled conditions. Earlier, we have demonstrated the feasibility of synthesizing aluminum-oxide particles in the high purity Fe-10Cr alloy by consecutive implantation with Al and O ions at room temperature. This paper describes the effects of high-temperature annealing after the ion implantation stage on the development of the aluminum based oxide nanoparticle system. Using transmission electron microscopy and atom probe tomography experiments, we demonstrate that post-implantation heat treatment induces the growth of the nano-sized oxides in the implanted region and nucleation of new oxide precipitates behind the implantation zone as a result of the diffusion driven broadening of implant profiles. A tentative scenario for the development of metal-oxide nano-particles at both ion implantation and heat treatment stages is suggested based on the experimental observations.

  4. Nanosized CoO Loaded on Copper Foam for High-Performance, Binder-Free Lithium-Ion Batteries.

    Science.gov (United States)

    Liao, Mingna; Zhang, Qilun; Tang, Fengling; Xu, Zhiwei; Zhou, Xin; Li, Youpeng; Zhang, Yali; Yang, Chenghao; Ru, Qiang; Zhao, Lingzhi

    2018-03-22

    The synthesis of nanosized CoO anodes with unique morphologies via a hydrothermal method is investigated. By adjusting the pH values of reaction solutions, nanoflakes (CoO-NFs) and nanoflowers (CoO-FLs) are successfully located on copper foam. Compared with CoO-FLs, CoO-NFs as anodes for lithium ion batteries present ameliorated lithium storage properties, such as good rate capability, excellent cycling stability, and large CoO nanoflakes; CoO nanoflowers; anodes; binder free; lithium ion batteriesreversible capacity. The initial discharge capacity is 1470 mA h g -1 , while the reversible capacity is maintained at 1776 m Ah g -1 after 80 cycles at a current density of 100 mA h g -1 . The excellent electrochemical performance is ascribed to enough free space and enhanced conductivity, which play crucial roles in facilitating electron transport during repetitive Li⁺ intercalation and extraction reaction as well as buffering the volume expansion.

  5. Nanosized CoO Loaded on Copper Foam for High-Performance, Binder-Free Lithium-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Mingna Liao

    2018-03-01

    Full Text Available The synthesis of nanosized CoO anodes with unique morphologies via a hydrothermal method is investigated. By adjusting the pH values of reaction solutions, nanoflakes (CoO-NFs and nanoflowers (CoO-FLs are successfully located on copper foam. Compared with CoO-FLs, CoO-NFs as anodes for lithium ion batteries present ameliorated lithium storage properties, such as good rate capability, excellent cycling stability, and large CoO nanoflakes; CoO nanoflowers; anodes; binder free; lithium ion batteriesreversible capacity. The initial discharge capacity is 1470 mA h g−1, while the reversible capacity is maintained at 1776 m Ah g−1 after 80 cycles at a current density of 100 mA h g−1. The excellent electrochemical performance is ascribed to enough free space and enhanced conductivity, which play crucial roles in facilitating electron transport during repetitive Li+ intercalation and extraction reaction as well as buffering the volume expansion.

  6. Toxicological evaluation of nano-sized colloidal silver in experiments on mice. behavioral reactions, morphology of internals

    Directory of Open Access Journals (Sweden)

    N.V. Zaitseva

    2015-06-01

    Full Text Available The results of toxicity studies of nano-sized colloidal silver (NCC, the most widely used in medicine, food and life, are given. When evaluating safe doses of silver NP (using commercially available NCC solution stabilized with polyvinylpyrrolidone (PVP, with the size of silver NP at the range of 5-80 nm when orally administered to male mice, BALB/c mice at doses of 0.1; 1.0 and 10 mg/kg of body weight per silver different effects from the motor and orienting-exploratory activity were revealed, for the part of them the dependence on the dose of the NCC was typical. The following peculiarities were found: reduction in motor activity to reduce the frequency of activities requiring physical effort, reduction of the execution time of these actions; increasing anxiety in terms of frequency and duration of attacks of orienting-investigative activity and animals washing. Morphological examination revealed a series of tissue changes of internal organs (especially liver and spleen, to a lesser extent – kidney, heart and colon with increase of the spectrum and severity of structural changes with increasing doses of the NCC. From the combination of the data the conclusion was made that maximal ineffective dose (NOAEL of this nanomaterial at subacute oral administration is no more than 0.1 mg/kg body weight.

  7. Nanostructural Features of Silver Nanoparticles Powder Synthesized through Concurrent Formation of the Nanosized Particles of Both Starch and Silver

    Directory of Open Access Journals (Sweden)

    A. Hebeish

    2013-01-01

    Full Text Available Green innovative strategy was developed to accomplish silver nanoparticles formation of starch-silver nanoparticles (St-AgNPs in the powder form. Thus, St-AgNPs were synthesized through concurrent formation of the nanosized particles of both starch and silver. The alkali dissolved starch acts as reducing agent for silver ions and as stabilizing agent for the formed AgNPs. The chemical reduction process occurred in water bath under high-speed homogenizer. After completion of the reaction, the colloidal solution of AgNPs coated with alkali dissolved starch was cooled and precipitated using ethanol. The powder precipitate was collected by centrifugation, then washed, and dried; St-AgNPs powder was characterized using state-of-the-art facilities including UV-vis spectroscopy, Transmission Electron Microscopy (TEM, particle size analyzer (PS, Polydispersity index (PdI, Zeta potential (ZP, XRD, FT-IR, EDX, and TGA. TEM and XRD indicate that the average size of pure AgNPs does not exceed 20 nm with spherical shape and high concentration of AgNPs (30000 ppm. The results obtained from TGA indicates that the higher thermal stability of starch coated AgNPS than that of starch nanoparticles alone. In addition to the data obtained from EDX which reveals the presence of AgNPs and the data obtained from particle size analyzer and zeta potential determination indicate that the good uniformity and the highly stability of St-AgNPs.

  8. Huge Inverse Magnetization Generated by Faraday Induction in Nano-Sized Au@Ni Core@Shell Nanoparticles

    Science.gov (United States)

    Kuo, Chen-Chen; Li, Chi-Yen; Lee, Chi-Hung; Li, Hsiao-Chi; Li, Wen-Hsien

    2015-01-01

    We report on the design and observation of huge inverse magnetizations pointing in the direction opposite to the applied magnetic field, induced in nano-sized amorphous Ni shells deposited on crystalline Au nanoparticles by turning the applied magnetic field off. The magnitude of the induced inverse magnetization is very sensitive to the field reduction rate as well as to the thermal and field processes before turning the magnetic field off, and can be as high as 54% of the magnetization prior to cutting off the applied magnetic field. Memory effect of the induced inverse magnetization is clearly revealed in the relaxation measurements. The relaxation of the inverse magnetization can be described by an exponential decay profile, with a critical exponent that can be effectively tuned by the wait time right after reaching the designated temperature and before the applied magnetic field is turned off. The key to these effects is to have the induced eddy current running beneath the amorphous Ni shells through Faraday induction. PMID:26307983

  9. Generation of nano-sized core-shell particles using a coaxial tri-capillary electrospray-template removal method.

    Science.gov (United States)

    Cao, Lihua; Luo, Jun; Tu, Kehua; Wang, Li-Qun; Jiang, Hongliang

    2014-03-01

    This study proposed a new strategy based on a coaxial tri-capillary electrospray-template removal process for producing nanosized polylactide-b-polyethylene glycol (PLA-PEG) particles with a core-shell structure. Microparticles with core-shell-corona structures were first fabricated by coaxial tri-capillary electrospray, and core-shell nanoparticles less than 200 nm in size were subsequently obtained by removing the PEG template from the core-shell-corona microparticles. The nanoparticle size could be modulated by adjusting the flow rate of corona fluid, and nanoparticles with an average diameter of 106±5 nm were obtained. The nanoparticles displayed excellent dispersion stability in aqueous media and very low cytotoxicity. Paclitaxel was used as a model drug to be incorporated into the core section of the nanoparticles. A drug loading content in the nanoparticles as high as 50.7±1.5 wt% with an encapsulation efficiency of greater than 70% could be achieved by simply increasing the feed rate of the drug solution. Paclitaxel exhibited sustained release from the nanoparticles for more than 40 days. The location of the paclitaxel in the nanoparticles, i.e., in the core or shell layer, did not have a significant effect on its release. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Synthesis and characterization of WC-Co nanosized composite powders with in situ carbon and gas carbon sources

    Science.gov (United States)

    Yang, Qiumin; Yang, Jiangao; Yang, Hailin; Su, Wei; Ruan, Jianming

    2016-07-01

    This study presented nanosized WC-Co composite powders synthesized using a one-step reduction-carbonization process with a combination of CH4/H2 as a gas carbon source and soluble starch as an in situ carbon source. The results of carbon analysis and X-ray diffraction revealed that WC-Co nanocomposite powders with a pure WC and Co phase could be obtained at 1100 °C after 0.5 h. A higher gas flow ratio of CH4/H2 during the reduction-carbonization process led to a higher total carbon content of the sample. A field emission scanning electron microscope confirmed that the particles in the WC-6 wt% Co composite powders had the lowest average size of 43 nm with equiaxed shapes. A sintering neck was observed in the WC-3 wt% Co composite powders whereas faceted particles were found in the WC-12 wt% Co composite powders. Moreover, this method has advantages of simple processing, rapid synthesis and good applicability in potential industry application.

  11. Synthesis and characterization of ZnS nanosized semiconductor particles within mesoporous solids.

    Science.gov (United States)

    Dimos, K; Koutselas, I B; Karakassides, M A

    2006-11-16

    ZnS semiconductor quantum dots have been synthesized using a method involving melt exchange reaction inside the pores of MCM-41 and subsequent reaction with H(2)S. The ZnS quantum dots-MCM-41 composite, which has been studied with XRD, EDS, and BET techniques, is shown to have retained within the pores the formed quantum dots, with a size distribution exhibiting a maximum nanoparticle diameter of ca. 1.8 nm. The structure and the sorption properties of the ZnS/MCM-41 composite have been studied by means of X-ray diffraction, Fourier transform infrared spectroscopy, and surface area measurements. All experimental data reveal that all the final composite products, containing up to 9.3 wt % ZnS as verified by EDS analysis, keep the basic structural characteristics of MCM-41 materials, without significant reduction of their active surface areas. The quantum dot optical properties have been studied with UV-vis, photoluminescence, and photoluminescence excitation spectroscopies providing evidence for the low-dimensional character of the ZnS semiconductor particles.

  12. Super-hydrophobic coatings with nano-size roughness prepared with simple PECVD method

    Science.gov (United States)

    Choi, Yoon S.; Lee, Joon S.; Jin, Su B.; Han, Jeon G.

    2013-08-01

    A simple and conventional method to synthesize nearly flat super-hydrophobic coatings was studied. Conventional plasma enhanced chemical vapour deposition (PECVD) was adopted to synthesize hydrophobic coatings on plastic and glass substrates at room temperature. Hexamethyldisilane was used as a precursor, and hydrogen gas was added to modulate the surface roughness and passivate defects, such as dangling bond and electrically uncovered polar sites rendering non-hydrophobicity. The static water contact angle (WCA) was controlled in the range 120°-160° by adjusting process parameters, especially the hydrogen flow rate and power. AFM showed that the film with a WCA of 145° has as small as 2.5 nm roughness in rms value. In the resistance test of salt water and cosmetics, this film showed excellent results owing to super-hydrophobicity and defect passivation which keeps the surface isolated from external agents. In order to exploit these results, Rare gas analysis was used to examine the process plasma and Fourier transform infrared (FTIR) was used to analyse the chemical structures of the super-hydrophobic films. In the FTIR results, the remarkable increase in the modes of Si-Hx and Si-C bonds as well as Si-CH2-Si in the film was observed indicating the defect passivation and closely packed dense film structure.

  13. Resistive switching and voltage induced modulation of tunneling magnetoresistance in nanosized perpendicular organic spin valves

    Directory of Open Access Journals (Sweden)

    Robert Göckeritz

    2016-04-01

    Full Text Available Nanoscale multifunctional perpendicular organic spin valves have been fabricated. The devices based on an La0.7Sr0.3MnO3/Alq3/Co trilayer show resistive switching of up to 4-5 orders of magnitude and magnetoresistance as high as -70% the latter even changing sign when voltage pulses are applied. This combination of phenomena is typically observed in multiferroic tunnel junctions where it is attributed to magnetoelectric coupling between a ferromagnet and a ferroelectric material. Modeling indicates that here the switching originates from a modification of the La0.7Sr0.3MnO3 surface. This modification influences the tunneling of charge carriers and thus both the electrical resistance and the tunneling magnetoresistance which occurs at pinholes in the organic layer.

  14. Enhancement of solubility of poorly water soluble anti hypertensive drug by nanosizing approach

    Directory of Open Access Journals (Sweden)

    Divyesh Thakar

    2012-01-01

    Full Text Available The objective of this research study was to optimize formulation and process variables affecting characteristic of nanosuspension in bead milling process. In this study, the practically water-insoluble telmisartan was nanoground by using top down method i.e. media milling method. Here the media used is ZnO 2 beads. A variety of surface active agents were tested for their stabilizing effects. Formulation factors evaluated were ratio of polymer to drug, whereas process parameters were milling time and concentration of ZnO 2 beads. Different concentration of stabilizers such as poloxamer 188, poloxamer 407, HPMC E 15, PVP K30 and combination of stabilizers were used for preparation of telmisartan nanosuspension. Responses measured in this study include particle size measurement, particle size distribution and zeta potential.

  15. Resistive switching and voltage induced modulation of tunneling magnetoresistance in nanosized perpendicular organic spin valves

    Energy Technology Data Exchange (ETDEWEB)

    Göckeritz, Robert; Homonnay, Nico; Müller, Alexander [Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle (Saale) (Germany); Fuhrmann, Bodo [Interdisziplinäres Zentrum für Materialwissenschaften, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle (Saale) (Germany); Schmidt, Georg, E-mail: georg.schmidt@physik.uni-halle.de [Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle (Saale) (Germany); Interdisziplinäres Zentrum für Materialwissenschaften, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle (Saale) (Germany)

    2016-04-15

    Nanoscale multifunctional perpendicular organic spin valves have been fabricated. The devices based on an La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/Alq3/Co trilayer show resistive switching of up to 4-5 orders of magnitude and magnetoresistance as high as -70% the latter even changing sign when voltage pulses are applied. This combination of phenomena is typically observed in multiferroic tunnel junctions where it is attributed to magnetoelectric coupling between a ferromagnet and a ferroelectric material. Modeling indicates that here the switching originates from a modification of the La{sub 0.7}Sr{sub 0.3}MnO{sub 3} surface. This modification influences the tunneling of charge carriers and thus both the electrical resistance and the tunneling magnetoresistance which occurs at pinholes in the organic layer.

  16. TEM and AFM study of WO3 nanosize growth on α-Al2O3

    International Nuclear Information System (INIS)

    Al-Mohammad, A.

    2007-07-01

    WO 3 thin films have been deposited by thermal evaporation on (0001) and (1012 ) planes of alumina oxide single crystal and annealed either in Oxygen or in air atmosphere. The morphology and crystallographic structure of films (as-deposited and annealed films) have been characterized by Atomic Force Microscope (AFM), transmission electron microscope (TEM), and transmission electron diffraction (TED). During annealing, the films undergo important morphological and structural changes. The annealed films exhibit large grains. These grains have the monoclinic structure in epitaxial orientations. The grains are made of twinned microdomains elongated in the [100] direction resulting of a preferential growth. The microdomains are along the three different directions on the (0001) α-Al 2 O 3 surface and only one direction on the (1012 ) α-Al 2 O 3 one.(author)

  17. Optical, structural and electrical properties of nanosized zinc oxide sintered films for photovoltaic applications

    Directory of Open Access Journals (Sweden)

    Kumar V.

    2013-01-01

    Full Text Available Zinc oxide films have been deposited on ultra-clean glass substrates by screenprinting method followed by sintering process. Optimum conditions for preparing good quality screen-printed films have been found. The optical band gap of the films has been studied using reflection spectra in wavelength range 325-600 nm by using double beam spectrophotometer. X-ray diffraction studies revealed that the films are polycrystalline in nature, single phase exhibiting wurtzite (hexagonal structure with strong preferential orientation of grains along the (101 direction. Surface morphology of films has been studied by scanning electron microscopy (SEM technique. The electrical resistivity of the films was measured in vacuum by two probe technique. PACS: 78.20.Ci; 78.50.Ge; 78.66.-w; 78.66.Hf.

  18. Polyether ether ketone implants achieve increased bone fusion when coated with nano-sized hydroxyapatite

    DEFF Research Database (Denmark)

    Johansson, Pär; Jimbo, Ryo; Naito, Yoshihito

    2016-01-01

    Polyether ether ketone (PEEK) possesses excellent mechanical properties similar to those of human bone and is considered the best alternative material other than titanium for orthopedic spine and trauma implants. However, the deficient osteogenic properties and the bioinertness of PEEK limit its...... fields of application. The aim of this study was to limit these drawbacks by coating the surface of PEEK with nano-scaled hydroxyapatite (HA) minerals. In the study, the biological response to PEEK, with and without HA coating, was investigated. Twenty-four screw-like and apically perforated implants...... in the rabbit femur were histologically evaluated at 3 weeks and 12 weeks after surgery. Twelve of the 24 implants were HA coated (test), and the remaining 12 served as uncoated PEEK controls. At 3 weeks and 12 weeks, the mean bone-implant contact was higher for test compared to control (P

  19. Preparation of nanosized yttrium doped CeO2 catalyst used for photocatalytic application

    Directory of Open Access Journals (Sweden)

    A. Akbari-Fakhrabadi

    2015-09-01

    Full Text Available In the present work, the pure CeO2 and yttrium doped CeO2 nanopowders were synthesized by the nitrate-fuel self-sustaining combustion method and calcined at 700 °C for 2 h. X-ray diffraction (XRD and high resolution electron transmission microscopy (HRTEM results demonstrated a cubic fluorite with high purity and the crystallite sizes less than 20 nm calculated from Scherrer’s formula. The BET specific surface area of yttrium doped CeO2 samples showed high values than those of pure CeO2. The photocatalytic activity of yttrium doped CeO2 showed high degradation of Rhodamine B solution under visible light illumination.

  20. Mucoadhesive nano-sized supramolecular assemblies for improved pre-corneal drug residence time.

    Science.gov (United States)

    Fabiano, Angela; Chetoni, Patrizia; Zambito, Ylenia

    2015-01-01

    Mucoadhesive nanoparticles were compared with non-aggregated constituent polymers for effect on pre-corneal residence of dexamethasone phosphate (DP) or met-enkephalin (ME), administered by eye-drops to rabbits. Deepening the knowledge of ophthalmic nanoparticulate systems in terms of ability to prolong pre-corneal residence. Medicated nanoparticles resulted from gelation of quaternary ammonium-chitosan conjugate or its thiolated derivative with hyaluronan in the presence of drug. Particles were analyzed by light scattering. Dialysis removed non-encapsulated drug, dynamic dialysis measured drug-polymer interactions, and lyophilization-stabilized product. Dispersions were regenerated from lyophilized products. Also solutions of non-thiolated or thiolated chitosan derivative were administered. Mean drug residence time (MRT) in tears was determined by collecting samples from lower marginal tear strip of albino rabbits using capillaries. Nanoparticle size of regenerated dispersions was 400-430 nm (DP-systems), 360-370 nm (ME-systems); the drug content was 2.5 mg/mL (DP) or 0.3 mg/mL (ME). The MRT for DP nanoparticles from non-thiolated derivative was higher than that for non-aggregated polymer, due to stronger concurrent interactions of positively charged nanoparticles with ocular surface and drug. Thiolated polymer nanoparticles and non-aggregated parent polymer, both interacting weakly with DP, showed similar MRT values. The MRT of ME could only be enhanced by protecting drug from enzymatic hydrolysis. This was done by nanoparticle systems, whereas non-aggregated polymers were ineffective. Developing a nanoparticle system rather than a solution of mucoadhesive polymer, for prolonging pre-corneal residence, is convenient, provided nanoparticles interact strongly with both ocular surface and drug, or protect drug from metabolic degradation.

  1. Reproductive and behavioral responses of earthworms exposed to nano-sized titanium dioxide in soil.

    Science.gov (United States)

    McShane, Heather; Sarrazin, Manon; Whalen, Joann K; Hendershot, William H; Sunahara, Geoffrey I

    2012-01-01

    Nanometer-sized titanium dioxide (nano-TiO(2) ) is found in a number of commercial products; however, its effects on soil biota are largely unknown. In the present study, earthworms (Eisenia andrei and Eisenia fetida) were exposed to three types of commercially available, uncoated TiO(2) nanomaterials with nominal diameters of 5, 10, and 21 nm. Nanomaterials were characterized for particle size, agglomeration, surface charge, chemical composition, and purity. Standard lethality, reproduction, and avoidance tests, as well as a juvenile growth test, were conducted in artificial soil or field soil amended with nano-TiO(2) by two methods, liquid dispersion and dry powder mixing. All studies included a micrometer-sized TiO(2) control. Exposure to field and artificial soil containing between 200 and 10,000 mg nano-TiO(2) per kilogram of dry soil (mg/kg) had no significant effect (p > 0.05) on juvenile survival and growth, adult earthworm survival, cocoon production, cocoon viability, or total number of juveniles hatched from these cocoons. However, earthworms avoided artificial soils amended with nano-TiO(2) . The lowest concentration at which avoidance was observed was between 1,000 and 5,000 mg nano-TiO(2) per kilogram of soil, depending on the TiO(2) nanomaterial applied. Furthermore, earthworms differentiated between soils amended with 10,000 mg/kg nano-TiO(2) and micrometer-sized TiO(2) . A positive relationship between earthworm avoidance and TiO(2) specific surface area was observed, but the relationship between avoidance and primary particle size was not determined because of the agglomeration and aggregation of nano-TiO(2) materials. Biological mechanisms that may explain earthworm avoidance of nano-TiO(2) are discussed. Results of the present study indicate that earthworms can detect nano-TiO(2) in soil, although exposure has no apparent effect on survival or standard reproductive parameters. Copyright © 2011 SETAC.

  2. Removal of Cr (VI from aqueous solutions by nano-sized magnetite modified with SDS

    Directory of Open Access Journals (Sweden)

    Ali Akbar Babaei

    2015-11-01

    Full Text Available Background: Contamination of aquatic bodies with heavy metals is a serious environmental problem. Chromium is a common contaminant in ground and surface water, soil and wastewater. The aim of this study was to use magnetite nanoparticles modified by sodium dodecyl sulphate (SDS for removal of hexavalent chromium from aqueous solutions and various factors affecting the uptake behavior such as pH, contact time, initial concentration of metal ions, adsorbent concentration, were studied. Materials & Methods: SDS modified magnetite nanoparticles were prepared by co-precipitation, and characterized by X-ray diffraction, SEM scaning electron microscopy. The XRD diffractogram showed purity of the magnetite nanoparticles and the SEM image showed that the modified magnetite particles were 50 nm. Results: The results showed that highest adsorption (99.7% for Cr(VI was occurred at pH=4, adsorbent dosage 2 g/L, initial concentration Cr(VI 10 mg/L and contact time 60 min. The adsorption data was correlated to different non-linear isotherm and kinetic models and the data fitted better to the Freundlich isotherm model. The kinetics of the Cr(VI adsorption followed Ho (Pseudo-second-order model. Conclusion: The SDS modified magnetite nanoparticles appears to be very effective at removing the Cr(VI from aqueous solution.

  3. Antifungal Activity of Amphotericin B Conjugated to Nanosized Magnetite in the Treatment of Paracoccidioidomycosis.

    Science.gov (United States)

    Saldanha, Camila Arruda; Garcia, Mônica Pereira; Iocca, Diego Cesar; Rebelo, Luciana Guilherme; Souza, Ana Camila Oliveira; Bocca, Anamélia Lorenzetti; Almeida Santos, Maria de Fátima Menezes; Morais, Paulo Cesar; Azevedo, Ricardo Bentes

    2016-06-01

    This study reports on in vitro and in vivo tests that sought to assess the antifungal activity of a newly developed magnetic carrier system comprising amphotericin B loaded onto the surface of pre-coated (with a double-layer of lauric acid) magnetite nanoparticles. The in vitro tests compared two drugs; i.e., this newly developed form and free amphotericin B. We found that this nanocomplex exhibited antifungal activity without cytotoxicity to human urinary cells and with low cytotoxicity to peritoneal macrophages. We also evaluated the efficacy of the nanocomplex in experimental paracoccidioidomycosis. BALB/c mice were intratracheally infected with Paracoccidioides brasiliensis and treated with the compound for 30 or 60 days beginning the day after infection. The newly developed amphotericin B coupled with magnetic nanoparticles was effective against experimental paracoccidioidomycosis, and it did not induce clinical, biochemical or histopathological alterations. The nanocomplex also did not induce genotoxic effects in bone marrow cells. Therefore, it is reasonable to believe that amphotericin B coupled to magnetic nanoparticles and stabilized with bilayer lauric acid is a promising nanotool for the treatment of the experimental paracoccidioidomycosis because it exhibited antifungal activity that was similar to that of free amphotericin B, did not induce adverse effects in therapeutic doses and allowed for a reduction in the number of applications.

  4. Antifungal Activity of Amphotericin B Conjugated to Nanosized Magnetite in the Treatment of Paracoccidioidomycosis.

    Directory of Open Access Journals (Sweden)

    Camila Arruda Saldanha

    2016-06-01

    Full Text Available This study reports on in vitro and in vivo tests that sought to assess the antifungal activity of a newly developed magnetic carrier system comprising amphotericin B loaded onto the surface of pre-coated (with a double-layer of lauric acid magnetite nanoparticles. The in vitro tests compared two drugs; i.e., this newly developed form and free amphotericin B. We found that this nanocomplex exhibited antifungal activity without cytotoxicity to human urinary cells and with low cytotoxicity to peritoneal macrophages. We also evaluated the efficacy of the nanocomplex in experimental paracoccidioidomycosis. BALB/c mice were intratracheally infected with Paracoccidioides brasiliensis and treated with the compound for 30 or 60 days beginning the day after infection. The newly developed amphotericin B coupled with magnetic nanoparticles was effective against experimental paracoccidioidomycosis, and it did not induce clinical, biochemical or histopathological alterations. The nanocomplex also did not induce genotoxic effects in bone marrow cells. Therefore, it is reasonable to believe that amphotericin B coupled to magnetic nanoparticles and stabilized with bilayer lauric acid is a promising nanotool for the treatment of the experimental paracoccidioidomycosis because it exhibited antifungal activity that was similar to that of free amphotericin B, did not induce adverse effects in therapeutic doses and allowed for a reduction in the number of applications.

  5. Optical sensing of biomedically important polyionic drugs using nano-sized gold particles.

    Science.gov (United States)

    Jena, Bikash Kumar; Raj, C Retna

    2008-03-14

    A simple optical method for the sensing of biomedically important polyionic drugs, protamine and heparin based on the reversible aggregation and de-aggregation of gold nanoparticles (AuNPs) is described. The polycationic protamine induces the aggregation of negatively charged citrate-stabilized AuNPs, resulting in a shift in the surface plasmon (SP) band and a consequent color change of the AuNPs from red to blue. Addition of polyanionic heparin dissipates the aggregated AuNPs due to its strong affinity to protamine and the blue color changes to the native color. The color change was monitored using UV-vis spectrophotometry. The aggregation and de-aggregation was confirmed by transmission electron microscopic (TEM) measurements. The degree of aggregation and de-aggregation is proportional to the concentration of added protamine and heparin, allowing their quantitative detection. The change in the absorbance and SP band position has been used to monitor the concentration of protamine and heparin. This optical method can quantify protamine and heparin as low as 0.1 microg/ml and 0.6 microg/ml, respectively and the calibration is linear for a wide range of concentration.

  6. Green's function approach to the Kondo effect in nanosized quantum corrals

    Science.gov (United States)

    Li, Q. L.; Wang, R.; Xie, K. X.; Li, X. X.; Zheng, C.; Cao, R. X.; Miao, B. F.; Sun, L.; Wang, B. G.; Ding, H. F.

    2018-04-01

    We present a theoretical study of the Kondo effect for a magnetic atom placed inside nanocorrals using Green's function calculations. Based on the standard mapping of the Anderson impurity model to a one-dimensional chain model, we formulate a weak-coupling theory to study the Anderson impurities in a hosting bath with a surface state. With further taking into account the multiple scattering effect of the surrounding atoms, our calculations show that the Kondo resonance width of the atom placed at the center of the nanocorral can be significantly tuned by the corral size, in good agreement with recent experiments [Q. L. Li et al., Phys. Rev. B 97, 035417 (2018), 10.1103/PhysRevB.97.035417]. The method can also be applied to the atom placed at an arbitrary position inside the corral where our calculation shows that the Kondo resonance width also oscillates as the function of its separation from the corral center. The prediction is further confirmed by the low-temperature scanning tunneling microscopy studies where a one-to-one correspondence is found. The good agreement with the experiments validates the generality of the method to the system where multiadatoms are involved.

  7. Characterization of epoxy hybrid composites filled with cellulose fibers and nano-SiC

    KAUST Repository

    Alamri, H.

    2012-04-06

    Three different approaches have been applied and investigated to enhance the thermal and mechanical properties of epoxy resin. Epoxy system reinforced with either recycled cellulose fibers (RCF) or nanosilicon carbide (n-SiC) particles as well as with both RCF and n-SiC has been fabricated and investigated. The effect of RCF/n-SiC dispersion on the mechanical and thermal properties of these composites has been characterized. The fracture surface morphology and toughness mechanisms were investigated by scanning electron microscopy. The dispersion of n-SiC particles into epoxy nanocomposites was studied by synchrotron radiation diffraction and transmission electron microscopy. Results indicated that mechanical properties increased as a result of the addition of n-SiC. The presence of RCF layers significantly increased the mechanical properties of RCF/epoxy composites when compared with neat epoxy and its nanocomposites. The influence of the addition of n-SiC to RCF/epoxy composites in mechanical properties was found to be positive in toughness properties. At high temperatures, thermal stability of neat epoxy increased due to the presence of either n-SiC particles or RCF layers. However, the presence of RCF accelerated the thermal degradation of neat epoxy as well as the addition of n-SiC to RCF/epoxy samples increased the rate of the major thermal degradation. © 2012 Wiley Periodicals, Inc.

  8. Tribological Properties of Laser Microtextured Surface Bonded With Composite Solid Lubricant at High Temperature.

    Science.gov (United States)

    Hua, Xijun; Sun, Jianguo; Zhang, Peiyun; Liu, Kai; Wang, Rong; Ji, Jinghu; Fu, Yonghong

    2016-07-01

    A combination technology of the solid lubricant and the laser surface texturing (LST) can significantly improve the tribological properties of friction pairs. The plate sample was textured by fiber laser and composite lubricant of polyimide (PI) and molybdenum disulfide (MoS 2 ) powders were filled in the microdimples. Sliding friction performances of micron-sized composite lubricant and nano-sized composite lubricant were investigated by ring-plate tribometer at temperatures ranging from room temperature (RT) to 400 °C. On the one hand, the results of the micron-sized composite lubricant show that the friction coefficient of the textured surface filled with composite lubricant (TS) exhibits the lowest level and the highest stability compared to a textured surface without solid lubrication, smooth surface without lubrication, smooth surface burnished with a layer of composite solid lubricant. The better dimple density range is 35-46%. The friction coefficients of the sample surface filled with micron-composite solid lubricant with the texture density of 35% are maintained at a low level (about 0.1) at temperatures ranging from RT to 300 °C. On the other hand, the results of the nano-sized composite lubricant show that these friction properties are better than those of MoS 2 -PI micron-sized composite. The friction coefficients of MoS 2 -PI-CNTs nano-sized composite solid lubricant are lower than those of the MoS 2 -PI composite lubricant at temperatures ranging from RT to 400 °C. In addition, the possible mechanisms involving the synergetic effect of the surface texture and the solid lubricant are discussed in the present work.

  9. Surface plasmon oscillations in a semi-bounded semiconductor plasma

    Science.gov (United States)

    M, SHAHMANSOURI; A, P. MISRA

    2018-02-01

    We study the dispersion properties of surface plasmon (SP) oscillations in a semi-bounded semiconductor plasma with the effects of the Coulomb exchange (CE) force associated with the spin polarization of electrons and holes as well as the effects of the Fermi degenerate pressure and the quantum Bohm potential. Starting from a quantum hydrodynamic model coupled to the Poisson equation, we derive the general dispersion relation for surface plasma waves. Previous results in this context are recovered. The dispersion properties of the surface waves are analyzed in some particular cases of interest and the relative influence of the quantum forces on these waves are also studied for a nano-sized GaAs semiconductor plasma. It is found that the CE effects significantly modify the behaviors of the SP waves. The present results are applicable to understand the propagation characteristics of surface waves in solid density plasmas.

  10. Self-organized monolayer of nanosized ceria colloids stabilized by poly(vinylpyrrolidone).

    Science.gov (United States)

    Si, Rui; Zhang, Ya-Wen; You, Li-Ping; Yan, Chun-Hua

    2006-03-30

    Four nanometer colloidal ceria nanocrystals in a fluorite cubic structure have been synthesized via an alcohothermal treatment at 180 degrees C for 24 h from Ce(NO(3))(3)*6H(2)O in ethanol, using various alkylamines including triethylamine, butylamine, and hexadecylamine as the bases and poly(vinylpyrrolidone) (PVP) as the stabilizer. They were characterized by multiple measurements of X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), ultraviolet visible (UV-vis) spectroscopy, dynamic light scattering (DLS), and infrared spectroscopy (IR). The introduction of PVP could effectively stabilize the cerium nuclei against self-aggregation and finally lead to the formation of the CeO(2) colloids. As compared with that of their precipitated counterparts, the UV-vis spectra showed a blue-shifted absorption edge for the as-obtained colloidal nanocrystals, revealing that their surfaces were well-passivated by PVP. Four types of self-organized monolayer patterns (i.e., isolated particles, short chainlike (pseudo-1-D aggregated), pearl necklace-like (1-D aggregated), and dendritic (pseudo-2-D aggregated) alignments) appeared for the as-obtained colloidal particles on the copper TEM grids, due to the delicate balance of the attractive and repulsive forces between the PVP-passivated CeO(2) nanocrystals during the irreversible evaporation of the solvent from various colloidal solutions under ambient conditions. The type of alkylamine and the concentration of PVP were confirmed to be the crucial factors determining the oriented-aggregation dimensionality of the CeO(2) colloids. Possible interparticle interaction modes have been suggested to explain such complex self-organization patterns exhibited by the as-obtained CeO(2) nanocrystals.

  11. Synthesis of nanosized vanadium pentoxide/carbon composites by spray pyrolysis for electrochemical capacitor application

    International Nuclear Information System (INIS)

    Wang Bei; Konstantinov, Konstantin; Wexler, David; Liu Hao; Wang Guoxiu

    2009-01-01

    Nanostructured vanadium pentoxide/carbon (V 2 O 5 /carbon) composite powders with enhanced specific capacitance were synthesized by the spray pyrolysis technique. Electrochemical properties were examined by the cyclic voltammetry technique. Following analysis of powders sprayed at different temperatures, composite powders obtained at an optimum temperature of 450 deg. C yielded a maximum specific capacitance of 295 F g -1 in 2 M KCl electrolyte at a 5-mV s -1 scan rate. The weight percentage of carbon-related species was 2.7 wt% in this V 2 O 5 /carbon composite, as detected by thermogravimetric analysis (TGA) and confirmed by transmission electron microscope energy dispersive spectroscopy (TEM-EDS) analysis. Following initial X-ray diffraction (XRD) characterization, scanning electron microscope (SEM), TEM and high-resolution TEM (HRTEM) imaging revealed a specific morphology of spherical shell agglomerates of V 2 O 5 nanorods and nanoribbons, with each shell comprising a network of these one- and two-dimensional nanoparticles in an amorphous carbon matrix. The V 2 O 5 network was not fully dense, and the majority of the nanorod sizes were in the range of 50-150 nm, with additional long nanoribbons extending from the outsides of the spherical shells. The specific surface area was 18 m 2 g -1 for the composite powders, and the pore size distribution revealed that the majority of pores had diameters in the range of 40-50 A, which was relatively larger than the pore diameters obtained at 500 deg. C and would be beneficial for electrochemical performance. The enhancement of the specific capacitance in V 2 O 5 /carbon composites was attributed to the distribution of amorphous carbon throughout the V 2 O 5 and the particular open nanostructure

  12. Nanosized titanium dioxide influences copper-induced toxicity during aging as a function of environmental conditions.

    Science.gov (United States)

    Rosenfeldt, Ricki R; Seitz, Frank; Haigis, Ann-Cathrin; Höger, Johanna; Zubrod, Jochen P; Schulz, Ralf; Bundschuh, Mirco

    2016-07-01

    Titanium dioxide nanoparticles (TiO2 -NPs) adsorb co-occurring heavy metals in surface waters, modulating their toxicity for freshwater invertebrates. The processes triggering this interaction may be influenced by several environmental parameters; however, their relative importance remains unclear. The present study assessed the implications of aging on the joint acute toxicity of copper (Cu) and TiO2 -NPs for Daphnia magna over a duration of up to 72 h. The influences of aging duration as well as ionic strength, pH, and presence of different qualities of organic matter during aging were assessed. The results indicated that the presence of TiO2 -NPs often reduced the Cu-induced toxicity for daphnids after aging (albeit with varying extent), which was displayed by up to 3-fold higher EC50 (50% effective concentration) values compared to the absence of TiO2 -NPs. Moreover, the Cu speciation, influenced by the ionic composition and the pH as well as the presence of organic additives in the medium, strongly modulated the processes during aging, with partly limited implications of the aging duration on the ecotoxicological response of D. magna. Nonetheless, the present study underpins the potential of TiO2 -NPs to modify toxicity induced by heavy metals in freshwater ecosystems under various environmental conditions. This pattern, however, needs further verification using heavy metal ions with differing properties in combination with further environmental factors, such as ultraviolet irradiation. Environ Toxicol Chem 2016;35:1766-1774. © 2015 SETAC. © 2015 SETAC.

  13. Photodegradation of organic matter in fresh garbage leachate using immobilized nano-sized TiO2 as catalysts.

    Science.gov (United States)

    Chen, C; Xie, Q; Hu, B Q; Zhao, X L

    2014-01-01

    Two immobilized nano-sized TiO2 catalysts, TiO2/activated carbon (TiO2/AC) and TiO2/silica gel (SG) (TiO2/SG), were prepared by the sol-gel method, and their use in the photocatalytic degradation of organic matter in fresh garbage leachate under UV irradiation was investigated. The influences of the catalyst dosage, the initial solution pH, H2O2 addition and the reuse of the catalysts were evaluated. The degradation of organic matter was assessed based on the decrease of the chemical oxygen demand (COD) in the leachate. The results indicated that the degradation of the COD obeyed first-order kinetics in the presence of both photocatalysts. The degradation rate of COD was found to increase with increasing catalyst dosage up to 9 g/L for TiO2/AC and 6 g/L for TiO2/SG, above which the degradation began to attenuate. Furthermore, the degradation rate first increased and then decreased as the solution pH increased from 2 to 14, and the degradation rate increased as the amount of H2O2 increased to 2.93 mM, after which it remained constant. No obvious decrease in the rate of COD degradation was observed during the first four repeated uses of the photocatalysts, indicating that the catalysts could be recovered and reused. Compared with TiO2/AC, TiO2/SG exhibited higher efficiency in photocatalyzing the degradation of COD in garbage leachate.

  14. Zebrafish as a visual and dynamic model to study the transport of nanosized drug delivery systems across the biological barriers.

    Science.gov (United States)

    Li, Ye; Miao, Xiaoqing; Chen, Tongkai; Yi, Xiang; Wang, Ruibing; Zhao, Haitao; Lee, Simon Ming-Yuen; Wang, Xueqing; Zheng, Ying

    2017-08-01

    With the wide application of nanotechnology to drug delivery systems, a simple, dynamic and visual in vivo model for high-throughput screening of novel formulations with fluorescence markers across biological barriers is desperately needed. In vitro cell culture models have been widely used, although they are far from a complimentary in vivo system. Mammalian animal models are common predictive models to study transport, but they are costly and time consuming. Zebrafish (Danio rerio), a small vertebrate model, have the potential to be developed as an "intermediate" model for quick evaluations. Based on our previously established coumarin 6 nanocrystals (C6-NCs), which have two different sizes, the present study investigates the transportation of C6-NCs across four biological barriers, including the chorion, blood brain barrier (BBB), blood retinal barrier (BRB) and gastrointestinal (GI) barrier, using zebrafish embryos and larvae as in vivo models. The biodistribution and elimination of C6 from different organs were quantified in adult zebrafish. The results showed that compared to 200nm C6-NCs, 70nm C6-NCs showed better permeability across these biological barriers. A FRET study suggested that intact C6-NCs together with the free dissolved form of C6 were absorbed into the larval zebrafish. More C6 was accumulated in different organs after incubation with small sized NCs via lipid raft-mediated endocytosis in adult zebrafish, which is consistent with the findings from in vitro cell monolayers and the zebrafish larvae model. C6-NCs could be gradually eliminated in each organ over time. This study demonstrated the successful application of zebrafish as a simple and dynamic model to simultaneously assess the transport of nanosized drug delivery systems across several biological barriers and biodistribution in different organs, especially in the brain, which could be used for central nervous system (CNS) drug and delivery system screening. Copyright © 2017 Elsevier B

  15. Radical change of Zn speciation in pig slurry amended soil: Key role of nano-sized sulfide particles.

    Science.gov (United States)

    Formentini, Thiago Augusto; Legros, Samuel; Fernandes, Cristovão Vicente Scapulatempo; Pinheiro, Adilson; Le Bars, Maureen; Levard, Clément; Mallmann, Fábio Joel Kochem; da Veiga, Milton; Doelsch, Emmanuel

    2017-03-01

    Spreading livestock manure as fertilizer on farmlands is a widespread practice. It represents the major source of heavy metal(loid)s (HM) input in agricultural soils. Since zinc (Zn) is present at high concentrations in manure, it poses special environmental concerns related to phytotoxicity, groundwater contamination, and introduction in the food chain. Therefore, investigations on the fate and behavior of manure-borne Zn, when it enters the soil environment, are necessary to predict the environmental effects. Nevertheless, long-term field studies assessing Zn speciation in the organic waste matrix, as well as within the soil after manure application, are lacking. This study was designed to fill this gap. Using SEM-EDS and XAS analysis, we reported the following new results: (i) ZnS made up 100% of the Zn speciation in the pig slurry (the highest proportion of ZnS ever observed in organic waste); and (ii) ZnS aggregates were about 1-μm diameter (the smallest particle size ever reported in pig slurry). Moreover, the pig slurry containing ZnS was spread on the soil over an 11-year period, totaling 22 applications, and the resulting Zn speciation within the amended soil was analyzed. Surprisingly, ZnS, i.e. the only species responsible for a nearly 2-fold increase in the Zn concentration within the amended soil, was not detected in this soil. Based on SEM-EDS and XAS observations, we put forward the hypothesis that Zn in the pig slurry consisted of nano-sized ZnS crystallites that further aggregated. The low stability of ZnS nanoparticles within oxic and complex environments such as the studied soil was the key explanation for the radical change in pig slurry-borne Zn speciation after long-term amendments. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Uptake and intracellular localization of submicron and nano-sized SiO₂ particles in HeLa cells.

    Science.gov (United States)

    Al-Rawi, Marco; Diabaté, Silvia; Weiss, Carsten

    2011-07-01

    Engineered amorphous silica nanoparticles (SiO(2)-NPs) are widely used in dyes, varnishes, plastics and glue, as well as in pharmaceuticals, cosmetics and food. Novel composite SiO(2)-NPs are promising multifunctional devices and combine labels for subsequent tracking and are functionalized e.g. to specifically target cells to deliver their cargo. However, biological and potential toxic effects of SiO(2)-NPs are insufficiently understood. The aim of this study was to determine the uptake and fate of SiO(2)-NPs in mammalian cells. Also, silica submicron particles (SiO(2)-SMPs) were included in the studies in order to identify effects, which are only observed for nano-sized SiO(2) particles. Fluorescently labelled SiO(2)-NPs (nominal size 70 nm) and SiO(2)-SMPs (nominal size 200 and 500 nm) were used to examine cytotoxicity, cellular uptake and localization in human cervical carcinoma cells (HeLa). Particle uptake and intracellular localization in mitochondria, endosomes, lysosomes and nuclei were studied by wide field and confocal laser scanning fluorescence microscopy. Physicochemical characterization of SiO(2)-NPs by transmission electron microscopy and dynamic light scattering revealed a spherical morphology and a monodisperse size distribution. In the presence of serum, all SiO(2) particles are non-toxic. However, in the absence of serum SiO(2)-NPs but not SiO(2)-SMPs are highly toxic. SiO(2) particles, irrespective of size, were detected in the cytosol and accumulated in endosomal compartments of HeLa cells. No accumulation of SiO(2) particles in nuclei or mitochondria of HeLa cells could be observed. In contrast to SiO(2)-SMPs, SiO(2)-NPs are preferentially localized in lysosomes.

  17. Metal load assessment in patient pulmonary lavages: towards a comprehensive mineralogical analysis including the nano-sized fraction.

    Science.gov (United States)

    Forest, Valérie; Vergnon, Jean-Michel; Guibert, Cyril; Bitounis, Dimitrios; Leclerc, Lara; Sarry, Gwendoline; Pourchez, Jérémie

    Mineralogical analyses of clinical samples have been proved useful to identify causal relationship between exposure to airborne particles and pulmonary diseases. The most striking example is asbestosis where the assessment of asbestos bodies in patient lung samples has allowed defining values specific of pathologies. However, this type of analyses only considers the micro-sized fraction of the particles, neglecting the specific impact of nano-sized particles which have been otherwise shown to be reactive and able to induce biological effects. Similarly, in nanotoxicology, the mineralogical analysis of pulmonary fluids could be used as an indicator of exposure to inhaled nanoparticles and could help investigations on the relationship between exposure to these nanoparticles and lung diseases. We designed this study first to demonstrate the technical feasibility of this approach, then to get a clear picture of the metals present, and in what form, in patient lungs and finally to determine if indeed it is worth investigating separately the micro, sub-micro and nano fractions. Broncho-alveolar lavages were recovered from 100 patients suffering from interstitial lung diseases. A protocol was specifically developed to isolate three fractions containing respectively microparticles, sub-microparticles and nanoparticles with ions. The metal content in each fraction was qualitatively and quantitatively characterized. Results showed significant differences between the three fractions in terms of metal load confirming that the separate analysis of the fractions is relevant. It also means that the assessment of the micro-sized fraction alone, as commonly done in clinical practice, only gives a partial view of the mineralogical analysis.

  18. Nano-Sized Structurally Disordered Metal Oxide Composite Aerogels as High-Power Anodes in Hybrid Supercapacitors.

    Science.gov (United States)

    Huang, Haijian; Wang, Xing; Tervoort, Elena; Zeng, Guobo; Liu, Tian; Chen, Xi; Sologubenko, Alla; Niederberger, Markus

    2018-03-27

    A general method for preparing nano-sized metal oxide nanoparticles with highly disordered crystal structure and their processing into stable aqueous dispersions is presented. With these nanoparticles as building blocks, a series of nanoparticles@reduced graphene oxide (rGO) composite aerogels are fabricated and directly used as high-power anodes for lithium-ion hybrid supercapacitors (Li-HSCs). To clarify the effect of the degree of disorder, control samples of crystalline nanoparticles with similar particle size are prepared. The results indicate that the structurally disordered samples show a significantly enhanced electrochemical performance compared to the crystalline counterparts. In particular, structurally disordered Ni x Fe y O z @rGO delivers a capacity of 388 mAh g -1 at 5 A g -1 , which is 6 times that of the crystalline sample. Disordered Ni x Fe y O z @rGO is taken as an example to study the reasons for the enhanced performance. Compared with the crystalline sample, density functional theory calculations reveal a smaller volume expansion during Li + insertion for the structurally disordered Ni x Fe y O z nanoparticles, and they are found to exhibit larger pseudocapacitive effects. Combined with an activated carbon (AC) cathode, full-cell tests of the lithium-ion hybrid supercapacitors are performed, demonstrating that the structurally disordered metal oxide nanoparticles@rGO||AC hybrid systems deliver high energy and power densities within the voltage range of 1.0-4.0 V. These results indicate that structurally disordered nanomaterials might be interesting candidates for exploring high-power anodes for Li-HSCs.

  19. Synthesis, characterization, nano-sized binuclear nickel complexes, DFT calculations and antibacterial evaluation of new macrocyclic Schiff base compounds

    Science.gov (United States)

    Parsaee, Zohreh; Mohammadi, Khosro

    2017-06-01

    Some new macrocyclic bridged dianilines tetradentate with N4coordination sphere Schiff base ligands and their nickel(II)complexes with general formula [{Ni2LCl4} where L = (C20H14N2X)2, X = SO2, O, CH2] have been synthesized. The compounds have been characterized by FT-IR, 1H and 13C NMR, mass spectroscopy, TGA, elemental analysis, molar conductivity and magnetic moment techniques. Scanning electron microscopy (SEM) shows nano-sized structures under 100 nm for nickel (II) complexes. NiO nanoparticle was achieved via the thermal decomposition method and analyzed by FT-IR, SEM and X-ray powder diffraction which indicates closeaccordance to standard pattern of NiO nanoparticle. All the Schiff bases and their complexes have been detected in vitro both for antibacterial activity against two gram-negative and two gram-positive bacteria. The nickel(II) complexes were found to be more active than the free macrocycle Schiff bases. In addition, computational studies of three ligands have been carried out at the DFT-B3LYP/6-31G+(d,p) level of theory on the spectroscopic properties, including IR, 1HNMR and 13CNMR spectroscopy. The correlation between the theoretical and the experimental vibrational frequencies, 1H NMR and 13C NMR of the ligands were 0.999, 0.930-0.973 and 0.917-0.995, respectively. Also, the energy gap was determined and by using HOMO and LUMO energy values, chemical hardness-softness, electronegativity and electrophilic index were calculated.

  20. Bactericidal Effect of Lauric Acid-Loaded PCL-PEG-PCL Nano-Sized Micelles on Skin Commensal Propionibacterium acnes

    Directory of Open Access Journals (Sweden)

    Thi-Quynh-Mai Tran

    2016-08-01

    Full Text Available Acne is the over growth of the commensal bacteria Propionibacterium acnes (P. acnes on human skin. Lauric acid (LA has been investigated as an effective candidate to suppress the activity of P. acnes. Although LA is nearly insoluble in water, dimethyl sulfoxide (DMSO has been reported to effectively solubilize LA. However, the toxicity of DMSO can limit the use of LA on the skin. In this study, LA-loaded poly(ɛ-caprolactone-poly(ethylene glycol-poly(ɛ-caprolactone micelles (PCL-PEG-PCL were developed to improve the bactericidal effect of free LA on P. acnes. The block copolymers mPEG-PCL and PCL-PEG-PCL with different molecular weights were synthesized and characterized using 1H Nuclear Magnetic Resonance spectroscopy (1H NMR, Fourier-transform infrared spectroscopy (FT-IR, Gel Permeation Chromatography (GPC, and Differential Scanning Calorimetry (DSC. In the presence of LA, mPEG-PCL diblock copolymers did not self-assemble into nano-sized micelles. On the contrary, the average particle sizes of the PCL-PEG-PCL micelles ranged from 50–198 nm for blank micelles and 27–89 nm for LA-loaded micelles. The drug loading content increased as the molecular weight of PCL-PEG-PCL polymer increased. Additionally, the minimum inhibitory concentration (MIC and the minimum bactericidal concentration (MBC of free LA were 20 and 80 μg/mL, respectively. The MICs and MBCs of the micelles decreased to 10 and 40 μg/mL, respectively. This study demonstrated that the LA-loaded micelles are a potential treatment for acne.

  1. Enhancement of flux pinning properties in nanosized MgO added Bi-2212 superconductor through neutron irradiation

    Science.gov (United States)

    Mohiju, Zaahidah'Atiqah; Hamid, Nasri A.; Abdullah, Yusof

    2017-01-01

    For superconducting material to maintain high critical current density, Jc in any applications, effective flux pinning centers are needed. The addition of small size MgO particles in bulk Bi2Sr2CaCu2O8 (Bi-2212) superconductor has been proven to enhance the effective flux pinning centers in the superconducting material by creating a desired microstructure with appropriate defects. To further enhance the pinning properties, radiation is one of the convenient ways to improve the microstructure of the material that has correlation with basic properties of superconductors. Neutron irradiation is one of the niche techniques that can be used to perform the task. Defects with larger radius have dimension comparable to the coherence length of the material and thus improved its superconducting properties. In this paper, a small amount of nanosized MgO particles was used to create defects in the Bi-2212 superconducting material. The Bi-2212/MgO compounds were heat treated, followed by partial melting and slow cooling. Part of the samples was subjected to neutron irradiation using the TRIGA-MARK-II research reactor at the Malaysian Nuclear Agency. Characterization of non-irradiated and irradiated samples was performed via the temperature dependence on electrical resistance measurements, X-ray Diffraction Patterns (XRD), and Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray (EDX) analysis. From the analysis, there was changed in the critical current density and transition temperature of samples subjected to neutron irradiation due to formation of point defects in the microstructure. Higher critical current density indicates better flux pinning properties in the Bi-2212/MgO compounds.

  2. Ultrasound-enhanced nanosized zero-valent copper activation of hydrogen peroxide for the degradation of norfloxacin.

    Science.gov (United States)

    Ma, Xiaoyan; Cheng, Yongqing; Ge, Yongjian; Wu, Huadan; Li, Qingsong; Gao, Naiyun; Deng, Jing

    2018-01-01

    Commercial nanosized zero-valent copper (nZVC) was used as hydrogen peroxide (H 2 O 2 ) activator in conjunction with ultrasonic irradiation (US) for the oxidative degradation of norfloxacin (NOR) in this study. Compared with silent degradation system, a significantly enhanced NOR removal was obtained in sono-advanced Fenton process, which involved a synergistic effect between sonolysis and Fenton-like reaction. Almost complete removal of NOR was achieved at 30min when the operating conditions were 0.25g/L nZVC and 10mM H 2 O 2 with ultrasound power of 240W at 20kHz. The released Cu + during the nZVC dissolution was the predominant copper species to activate H 2 O 2 and yield hydroxyl radicals (OH) in US/nZVC/H 2 O 2 system. According to the radical quenching experiments and electron paramagnetic resonance technique, hydroxyl radicals in solution (OH free ) were verified as the primary reactive species, and superoxide anion radicals (O 2 - ) were regarded as the mediator for the copper cycling by reduction of Cu 2+ to Cu + . NOR removal efficiencies were improved in various degrees when increased nZVC dosage, ultrasound power, hydrogen-ion amount and H 2 O 2 concentration. Moreover, the inhibitory effect of different inorganic salts on NOR degradation followed the sequence of Na 2 SO 4 >NaNO 3 ≈no salt>NaCl>NaHCO 3 . Finally, eleven intermediates were identified and five oxidation pathways were proposed, the cleavage of piperazine ring and transformation of quinolone group seemed to be the major pathway. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Enhanced sun protection of nano-sized metal oxide particles over conventional metal oxide particles: an in vitro comparative study.

    Science.gov (United States)

    Singh, P; Nanda, A

    2014-06-01

    A systematic and detailed study has been designed and conducted, taking into account some of the proposed benefits such as increased efficiency, transparency, unique texture, protection of active ingredient and higher consumer compliance of cosmetics containing nano-sized metal oxides. This study also presents an in vitro method to determine sun protection factor of the investigational sunscreen cream samples containing zinc oxide and titanium dioxide with a varied range of particle size. Finally, a comparative study has been conducted between metal oxide particles, conventional as well as nanoparticles. All the skin cosmetics formulated were thermally stable with a pH ranging from 7.9 to 8.2. Moreover, the fatty acid substance content and residue were found to be analogous to the standard values in each skin cosmetic. The skin cosmetics containing the titanium or zinc oxide nanoparticles were found to have improved spreadability as compared to skin cosmetics containing conventional titanium or zinc oxide particles, respectively. All skin cosmetics were found to have uniform distribution of the particles. The sunscreen creams containing zinc oxide nanoparticles and titanium dioxide nanoparticles were found to have higher in vitro sun protection factor (SPF of 3.65 for ZnO nanoparticles and 4.93 for TiO2 nanoparticles) as compared to that of sunscreen creams containing conventional zinc oxide particles (SPF = 2.90) and conventional titanium dioxide (SPF = 1.29), clearly indicating the effect of reduction in particles size, from micro to nano, on the sun protection factor. Good texture, better spreadability and enhanced in vitro SPF proved the advantageous role of nanoparticles in cosmetics. © 2014 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  4. Textural, structural, and morphological characterizations and catalytic activity of nanosized CeO(2)-MO(x) (M=Mg(2+), Al(3+), Si(4+)) mixed oxides for CO oxidation.

    Science.gov (United States)

    Yu, Qiang; Wu, Xiaoxia; Tang, Changjin; Qi, Lei; Liu, Bin; Gao, Fei; Sun, Keqin; Dong, Lin; Chen, Yi

    2011-02-01

    The present work focuses on the combination of ceria with another oxide of different ionic valences from period 3 (Mg(2+), Al(3+), and Si(4+)) using coprecipitation method, followed by calcination at 450 and 750°C, respectively. The textural, structural, morphological and redox properties of nanosized ceria-magnesia, ceria-alumina and ceria-silica mixed oxides have been investigated by means of N(2) physisorption, XRD, Raman, HRTEM, DRS, FT-IR, and H(2)-TPR technologies. XRD results of these mixed oxides reveal that only nanocrystalline ceria (ca. 3-6nm for the 450°C calcined samples) could be observed. The grain size of ceria increases with the increasing calcination temperature from 450 to 750°C due to sintering effect. The highest specific surface area is obtained at CeO(2)-Al(2)O(3) mixed oxides when calcination temperature reaches 750°C. Raman spectra display the cubic fluorite structure of ceria and the existence of oxygen vacancies, and displacement of oxygen ions from their normal lattice positions in the ceria-based mixed oxides. DRS measurements confirm that the smaller the grain size of the ceria, the higher indirect band gap energy. H(2)-TPR results suggest that the reductions of surface and bulk oxygen of ceria were predominant at low and high calcination temperature, respectively. Finally, CO oxidation were performed over these ceria-based mixed oxides, and the combination of CeO(2)-Al(2)O(3) exhibited highest activity irrespective of calcination temperature, which may due to excellent textural/structural properties, good homogeneity, and redox abilities. Copyright © 2010 Elsevier Inc. All rights reserved.

  5. Nanosized sustained-release drug depots fabricated using modified tri-axial electrospinning.

    Science.gov (United States)

    Yang, Guang-Zhi; Li, Jiao-Jiao; Yu, Deng-Guang; He, Mei-Feng; Yang, Jun-He; Williams, Gareth R

    2017-04-15

    Nanoscale drug depots, comprising a drug reservoir surrounded by a carrier membrane, are much sought after in contemporary pharmaceutical research. Using cellulose acetate (CA) as a filament-forming polymeric matrix and ferulic acid (FA) as a model drug, nanoscale drug depots in the form of core-shell fibers were designed and fabricated using a modified tri-axial electrospinning process. This employed a solvent mixture as the outer working fluid, as a result of which a robust and continuous preparation process could be achieved. The fiber-based depots had a linear morphology, smooth surfaces, and an average diameter of 0.62±0.07μm. Electron microscopy data showed them to have clear core-shell structures, with the FA encapsulated inside a CA shell. X-ray diffraction and IR spectroscopy results verified that FA was present in the crystalline physical form. In vitro dissolution tests revealed that the fibers were able to provide close to zero-order release over 36h, with no initial burst release and minimal tailing-off. The release properties of the depot systems were much improved over monolithic CA/FA fibers, which exhibited a significant burst release and also considerable tailing-off at the end of the release experiment. Here we thus demonstrate the concept of using modified tri-axial electrospinning to design and develop new types of heterogeneous nanoscale biomaterials. Nanoscale drug depots with a drug reservoir surrounded by a carrier are highly attractive in biomedicine. A cellulose acetate based drug depot was investigated in detail, starting with the design of the nanostructure, and moving through its fabrication using a modified tri-axial electrospinning process and a series of characterizations. The core-shell fiber-based drug depots can provide a more sustained release profile with no initial burst effect and less tailing-off than equivalent monolithic drug-loaded fibers. The drug release mechanisms are also distinct in the two systems. This proof

  6. Characterisation of micro-sized and nano-sized tungsten oxide-epoxy composites for radiation shielding of diagnostic X-rays

    International Nuclear Information System (INIS)

    Noor Azman, N.Z.; Siddiqui, S.A.; Low, I.M.

    2013-01-01

    Characteristics of X-ray transmissions were investigated for epoxy composites filled with 2–10 vol% WO 3 loadings using synchrotron X-ray absorption spectroscopy (XAS) at 10–40 keV. The results obtained were used to determine the equivalent X-ray energies for the operating X-ray tube voltages of mammography and radiology machines. The results confirmed the superior attenuation ability of nano-sized WO 3 -epoxy composites in the energy range of 10–25 keV when compared to their micro-sized counterparts. However, at higher synchrotron radiation energies (i.e., 30–40 keV), the X-ray transmission characteristics were similar with no apparent size effect for both nano-sized and micro-sized WO 3 -epoxy composites. The equivalent X-ray energies for the operating X-ray tube voltages of the mammography unit (25–49 kV) were in the range of 15–25 keV. Similarly, for a radiology unit operating at 40–60 kV, the equivalent energy range was 25–40 keV, and for operating voltages greater than 60 kV (i.e., 70–100 kV), the equivalent energy was in excess of 40 keV. The mechanical properties of epoxy composites increased initially with an increase in the filler loading but a further increase in the WO 3 loading resulted in deterioration of flexural strength, modulus and hardness. - Highlights: • Nano-sized WO 3 -epoxy composites have superior x-ray shielding capability. • No size effect in x-ray attenuation was observed at 30–40 keV. • An optimum filler loading for improving the mechanical properties of WO 3 -epoxy composites

  7. Fabrication of a nanosize-Pt-embedded membrane electrode assembly to enhance the utilization of Pt in proton exchange membrane fuel cells.

    Science.gov (United States)

    Choe, Junseok; Kim, Doyoung; Shim, Jinyong; Lee, Inhae; Tak, Yongsug

    2011-08-01

    A procedure to locate the Pt nanostructure inside the hydrophilic channel of a Nafion membrane was developed in order to enhance Pt utilization in PEMFCs. Nanosize Pt-embedded MEA was constructed by Cu electroless plating and subsequent Pt electrodeposition inside the hydrophilic channels of the Nafion membrane. The metallic Pt nanostructure fabricated inside the membrane was employed as an oxygen reduction catalyst for a PEMFC and facilitated effective use of the hydrophilic channels inside the membrane. Compared to the conventional MEA, a Pt-embedded MEA with only 68% Pt loading showed better PEMFC performance.

  8. Surface hardening alloy VT6 of electric explosion and by electron beam

    International Nuclear Information System (INIS)

    Ivanov, Yu. F.; Kobzareva, T. Yu.; Gromov, V. E.; Soskova, N. A.; Budovskikh, E. A.; Raikov, S. V.

    2014-01-01

    The aim is to study the phase composition, structure and properties of the surface layer of the VT6 titanium alloy, subjected to combined treatment, consisting of alloying by the plasma of an electric explosion of a graphite fiber with a charge of the SiC powder and subsequent exposure by a high-intense electron beam. As a result of such treatment, a multiphase surface layer with a submicron and nanosize structure forms with the microhardness manifold exceeding its value in the sample volume are presented

  9. The influence of size on the toxicity of an encapsulated pesticide: a comparison of micron- and nano-sized capsules.

    Science.gov (United States)

    Meredith, Alicea N; Harper, Bryan; Harper, Stacey L

    2016-01-01

    Encapsulation technology involves entrapping a chemical active ingredient (a.i.) inside a hollow polymeric shell and has been applied to commercial pesticide manufacturing for years to produce capsule suspension (CS) formulations with average particle sizes in the micron-scale. The few literature sources that investigate the environmental fate and toxicity to non-target organisms of encapsulated commercially available pesticide products with regard to capsule size report on average sizes between 20 and 50 μm. Here, we have identified a CS formulation with an average capsule size of approximately 2 μm with some capsules extending into the nanometer scale (~200 nm). Determining how carrier size influences toxicity is important to understanding if current pesticide risk assessments are sufficient to protect against products that incorporate encapsulation technology. Here, a commercial pyrethroid CS pesticide with lambda-cyhalothrin (λ-Cy) as the a.i. was separated into two suspensions, a fraction consisting of nano-sized capsules (~250 nm) and a fraction of micron-sized capsules (~2200 nm) in order to investigate the influence of capsule size on toxicity to embryonic zebrafish, Danio rerio. Toxicity was evaluated 24h after exposure to equivalent amounts of a.i. by the presence and severity of pyrethroid-specific tremors, 14 sublethal developmental impacts and mortality. Fish exposed to greater than 20 μg a.i. L(-1) technical λ-Cy or formulated product experienced curvature of the body axis, pericardial edema, craniofacial malformations, and mortality. Exposure to the unfractionated formulation, micro fraction, nano fraction and technical a.i. resulted in no significant differences in the occurrence of sublethal impacts or mortality; however, the technical a.i. exposure resulted in significantly less fish experiencing tremors and shorter tremors compared to any of the formulated product exposures. This suggests that the capsule size does not influence the toxic

  10. Diethyl citrate and sodium citrate reduce the cytotoxic effects of nanosized hydroxyapatite crystals on mouse vascular smooth muscle cells

    Directory of Open Access Journals (Sweden)

    Zhang CY

    2017-11-01

    Full Text Available Chong-Yu Zhang,1 Xin-Yuan Sun,1 Jian-Ming Ouyang,1 Bao-Song Gui2 1Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou, 2Department of Nephrology, The Second Hospital of Xi’an Jiaotong University, Xi’an, People’s Republic of China Objective: This study aimed to investigate the damage mechanism of nanosized hydroxyapatite (nano-HAp on mouse aortic smooth muscle cells (MOVASs and the injury-inhibiting effects of diethyl citrate (Et2Cit and sodium citrate (Na3Cit to develop new drugs that can simultaneously induce anticoagulation and inhibit vascular calcification. Methods: The change in cell viability was evaluated using a cell proliferation assay kit, and the amount of lactate dehydrogenase (LDH released was measured using an LDH kit. Intracellular reactive oxygen species (ROS and mitochondrial damage were detected by DCFH-DA staining and JC-1 staining. Cell apoptosis and necrosis were detected by Annexin V staining. Intracellular calcium concentration and lysosomal integrity were measured using Fluo-4/AM and acridine orange, respectively. Results: Nano-HAp decreased cell viability and damaged the cell membrane, resulting in the release of a large amount of LDH. Nano-HAp entered the cells and damaged the mitochondria, and then induced cell apoptosis by producing a large amount of ROS. In addition, nano-HAp increased the intracellular Ca2+ concentration, leading to lysosomal rupture and cell necrosis. On addition of the anticoagulant Et2Cit or Na3Cit, cell viability and mitochondrial membrane potential increased, whereas the amount of LDH released, ROS, and apoptosis rate decreased. Et2Cit and Na3Cit could also chelate with Ca2+ to inhibit the intracellular Ca2+ elevations induced by nano-HAp, prevent lysosomal rupture, and reduce cell necrosis. High concentrations of Et2Cit and Na3Cit exhibited strong inhibitory effects. The inhibitory capacity of Na3Cit was stronger than that of Et2Cit at similar

  11. Reversible and Irreversible Binding of Nanoparticles to Polymeric Surfaces

    Directory of Open Access Journals (Sweden)

    Wolfgang H. Binder

    2009-01-01

    Full Text Available Reversible and irreversible binding of CdSe-nanoparticles and nanorods to polymeric surfaces via a strong, multiple hydrogen bond (= Hamilton-receptor/barbituric acid is described. Based on ROMP-copolymers, the supramolecular interaction on a thin polymer film is controlled by living polymerization methods, attaching the Hamilton-receptor in various architectures, and concentrations. Strong binding is observed with CdSe-nanoparticles and CdSe-nanorods, whose surfaces are equipped with matching barbituric acid-moieties. Addition of polar solvents, able to break the hydrogen bonds leads to the detachment of the nanoparticles from the polymeric film. Irreversible binding is observed if an azide/alkine-“click”-reaction is conducted after supramolecular recognition of the nanoparticles on the polymeric surface. Thus reversible or irreversible attachment of the nanosized objects can be achieved.

  12. Surface electronic properties of discontinuous Pd films during hydrogen exposure

    International Nuclear Information System (INIS)

    Zhao, Ming; Nagata, Shinji; Shikama, Tatsuo; Inouye, Aichi; Yamamoto, Shunya; Yoshikawa, Masahito

    2011-01-01

    This paper explored the change in the surface resistance of the discontinuous palladium (Pd) films during hydrogen exposure. In our experiments, we observed a remarkable rise in the electrical resistance of the discontinuous film which consists of nano-sized particles, when it was exposed to thin hydrogen. By studying the resistance change ratio before and after hydrogen exposure, we have found that it demonstrates an inverse exponential relationship with the ratio of on-film particle radius to the inter island separation. This suggests that the change in the film resistance under hydrogen exposure is primarily associated with the variation of surface work function which is caused by the hydrogen absorption on the Pd surface. (author)

  13. Sonochemical synthesis, characterization, thermal and semiconducting behavior of nano-sized azidopentaamminecobalt(III) complexes containing anion, CrO42-or Cr2O72.

    Science.gov (United States)

    Bala, Ritu; Behal, Jagriti; Shah, Nikesh A; Rathod, K N; Prakash, Vinit; Khunt, Ranjan C

    2018-03-01

    New nano-sized cobalt(III) coordination complexes, [Co(NH 3 ) 5 N 3 ]CrO 4 (1N) and [Co(NH 3 ) 5 N 3 ]Cr 2 O 7 (2N) were synthesized using an innovative sonochemical methodology based on reaction between [Co(NH 3 ) 5 N 3 ]Cl 2 and potassium salt of CrO 4 2- or Cr 2 O 7 2- in aqueous medium. These complexes were also compared with their respective bulks which were synthesized under identical conditions in the absence of sonicaion. All the complexes were characterized by elemental analysis and spectroscopic techniques (UV-visible and IR). Morphology and particle size of nano-sized complexes was determined by SEM and Zeta-sizer respectively. TGA was used for comparative thermal stability and XRD to identify the phase difference between nano structures and bulk complexes. Furthermore, the electrical property was investigated and all complexes were found to be electrical semiconducting materials and 2N shows better result than others. The single crystals X-ray structure study of new [Co(NH 3 ) 5 N 3 ]Cr 2 O 7 revealed the presence of discrete ions, [Co(NH 3 ) 5 N 3 ] 2+ and Cr 2 O 7 2- , crystallizes in monoclinic, space group P c , with R=0.0636 in the solid state. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Particle phase distribution of polycyclic aromatic hydrocarbons in stormwater--Using humic acid and iron nano-sized colloids as test particles.

    Science.gov (United States)

    Nielsen, Katrine; Kalmykova, Yuliya; Strömvall, Ann-Margret; Baun, Anders; Eriksson, Eva

    2015-11-01

    The distribution of polycyclic aromatic hydrocarbons (PAHs) in different particulate fractions in stormwater: Total, Particulate, Filtrated, Colloidal and Dissolved fractions, were examined and compared to synthetic suspensions of humic acid colloids and iron nano-sized particles. The distribution of low-molecular weight PAHs (LMW PAHs), middle-molecular weight PAHs (MMW PAHs) and high-molecular weight PAHs (HMW PAHs) among the fractions was also evaluated. The results from the synthetic suspensions showed that the highest concentrations of the PAHs were found in the Filtrated fractions and, surprisingly, high loads were found in the Dissolved fractions. The PAHs identified in stormwater in the Particulate fractions and Dissolved fractions follow their hydrophobic properties. In most samples >50% of the HMW PAHs were found in the Particulate fractions, while the LMW and MMW PAHs were found to a higher extent in the Filtrated fractions. The highest concentrations of PAHs were present in the stormwater with the highest total suspended solids (TSS); the relative amount of the HMW PAHs was highest in the Particulate fractions (particles>0.7 μm). The highest concentration of PAHs in the Colloidal fraction was found in the sample with occurrence of small nano-sized particles (<10nm). The results show the importance of developing technologies that both can manage particulate matter and effectively remove PAHs present in the Colloidal and Dissolved fractions in stormwater. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Improved Light Conversion Efficiency Of Dye-Sensitized Solar Cell By Dispersing Submicron-Sized Granules Into The Nano-Sized TiO2 Layer

    Directory of Open Access Journals (Sweden)

    Song S.A.

    2015-06-01

    Full Text Available In this work, TiO2 nanoparticles and submicron-sized granules were synthesized by a hydrothermal method and spray pyrolysis, respectively. Submicron-sized granules were dispersed into the nano-sized TiO2 layer to improve the light conversion efficiency. Granules showed better light scattering, but lower in terms of the dye-loading quantity and recombination resistance compared with nanoparticles. Consequently, the nano-sized TiO2 layer had higher cell efficiency than the granulized TiO2 layer. When dispersed granules into the nanoparticle layer, the light scattering was enhanced without the loss of dye-loading quantities. The dispersion of granulized TiO2 led to increase the cell efficiency up to 6.51%, which was about 5.2 % higher than that of the electrode consisting of only TiO2 nanoparticles. Finally, the optimal hydrothermal temperature and dispersing quantity of granules were found to be 200°C and 20 wt%, respectively.

  16. Strengthening Effect of Extruded Mg-8Sn-2Zn-2Al Alloy: Influence of Micro and Nano-Size Mg2Sn Precipitates

    Science.gov (United States)

    Cheng, Weili; Bai, Yang; Wang, Lifei; Wang, Hongxia; Bian, Liping; Yu, Hui

    2017-01-01

    In this study, Mg-8Sn-2Zn-2Al (TZA822) alloys with varying Mg2Sn contents prior to extrusion were obtained by different pre-treatments (without and with T4), and the strengthening response related to micro and nano-size Mg2Sn precipitates in the extruded TZA822 alloys was reported. The results showed that the morphology of nano-size Mg2Sn precipitates exhibits a significant change in basal plane from rod-like to spherical, owing to the decrement in the fraction of micro-size particles before extrusion. Meanwhile, the spherical Mg2Sn precipitates provided a much stronger strengthening effect than did the rod-like ones, which was ascribed to uniform dispersion and refinement of spherical precipitates to effectively hinder basal dislocation slip. As a consequence, the extruded TZA822 alloy with T4 showed a higher tensile yield strength (TYS) of 245 MPa, ultimate tensile strength (UTS) of 320 MPa and elongation (EL) of 26.5%, as well as a lower degree of yield asymmetry than their counterpart without T4. Detailed reasons for the strengthening effect were given and analyzed. PMID:28773180

  17. A simple and general route for the preparation of pure and high crystalline nanosized lanthanide silicates with the structure of apatite at low temperature

    International Nuclear Information System (INIS)

    Ferdov, Stanislav; Rauwel, Protima; Lin, Zhi; Ferreira, Rute A. Sa; Lopes, Augusto

    2010-01-01

    Rare earth silicates with the structure of apatite are attracting considerable interest since they show oxygen ion conductivities higher than that of yttria-stabilized zirconia (YSZ) at moderate temperature. Based on the hydrothermal synthesis we presented a simple one step process for the direct preparation of the pure and the high crystalline nanosized rare earth silicates with the structure of apatite under a mild condition (230 o C). Since the preparation of the high crystalline silicon based rare earth apatites is performed at high temperature previously and accompanied by subsequent process of grinding, results of this work provide a promising alternative of the existing methodology. Furthermore, due to the relatively low temperature of the preparation of these materials, high doping of monovalent cation can be done, which was not achieved before. -- Graphical abstract: A simple one step process for the preparation of the rare earth silicates with the structure of apatite under a mild condition (230 o C) is presented. The process is based on the hydrothermal synthesis and the obtained powder materials are pure, high crystalline and with nanosize. Display Omitted

  18. Effect of pulsed and continuous ultrasound on structural and magnetic properties of nano-sized Ni0.4Cu0.2Zn0.4Fe2O4 ferrite

    Science.gov (United States)

    Hassen, Harzali; Adel, Megriche; Arbi, Mgaidi

    2018-03-01

    Ultrasound-assisted co-precipitation has been used to prepare nano-sized Ni0.4Cu0.2Zn0.4Fe2O4 ferrite. Continuous (C-US) and pulsed (P-US) ultrasound modes are used at constant frequency = 20 kHz, reaction time = 2 h and pulse durations of 10 s on and 10 s off. All experiments were conducted at two temperatures 90 and 100°C. Samples were characterized by X-ray diffraction (XRD), Fourier transform spectroscopy (FT-IR), N2 adsorption isotherms at 77 k analysis (BET), transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM) techniques. A nanocrystalline single-phase with particle size in the range 12-18 nm is obtained in both modes: continuous and pulsed ultrasound mode. FT-IR measurements show two absorption bands assigned to the tetrahedral and octahedral vibrations (ν1 and ν2) characteristics of cubic spinel ferrite. The specific surface area (S BET) is in the range of 110-140 m2 g-1 and an average pore size between 5.5 and 6.5 nm. The lowest values are obtained in pulsed mode. Finally, this work shows that the magnetic properties are affected by the ultrasound conditions, without affecting the particle shape. The saturation magnetization (Ms) values obtained for all samples are comparable. In P-US mode, the saturation magnetization (Ms) increases as temperature increases. Moreover, P-US mode opens a new avenue for synthesis of NiCuZn ferrites.

  19. Magnetism, Nanosized Magnetic Materials

    Science.gov (United States)

    Miller, Joel S.; Drillon, Marc

    2002-01-01

    Magnetic behaviour, once thought to be mature, has gained a new momentum as it is being expanded by contributions from molecular chemistry, materials sciences to solid state physics. The spectrum spans molecule-based - organic, inorganic, and hybrid - compounds, metallic materials as well as their oxides forming, for example, thin films, nanoparticles, nanowires. New phenomena are explored that open promising perspectives for commercially applied "smart" materials. As a depository of contemporary knowledge on key topics related to magnetism, this open series of volumes provides a much-needed comprehensive overview of this growing interdisciplinary field. The topical reviews are written by the foremost scientists in the area, and the trends and recent advances are explained in a clear and detailed manner with a focus on the correlations between electronic structure and magnetic properties. The balance between theory and experiment within this series will guide advanced students and specialists in evaluating experimental observations and will serve as a basis for the design of new magnetic materials. This is a unique reference work, indispensable for everyone concerned with the phenomena of magnetism!

  20. Nanosized blood microparticles

    NARCIS (Netherlands)

    Yuana, Yuana

    2011-01-01

    Microparticles (MPs) have important physiological and pathological roles in blood coagulation, inflammation and tumor progression. In recent years MPs also have been recognized to participate in important biological processes, such as in signaling and in the horizontal transfer of their specific

  1. Thermal and UV Hydrosilylation of Alcohol-Based Bifunctional Alkynes on Si (111) surfaces: How surface radicals influence surface bond formation

    Science.gov (United States)

    Khung, Y. L.; Ngalim, S. H.; Scaccabarozi, A.; Narducci, D.

    2015-06-01

    Using two different hydrosilylation methods, low temperature thermal and UV initiation, silicon (111) hydrogenated surfaces were functionalized in presence of an OH-terminated alkyne, a CF3-terminated alkyne and a mixed equimolar ratio of the two alkynes. XPS studies revealed that in the absence of premeditated surface radical through low temperature hydrosilylation, the surface grafting proceeded to form a Si-O-C linkage via nucleophilic reaction through the OH group of the alkyne. This led to a small increase in surface roughness as well as an increase in hydrophobicity and this effect was attributed to the surficial etching of silicon to form nanosize pores (~1-3 nm) by residual water/oxygen as a result of changes to surface polarity from the grafting. Furthermore in the radical-free thermal environment, a mix in equimolar of these two short alkynes can achieve a high contact angle of ~102°, comparable to long alkyl chains grafting reported in literature although surface roughness was relatively mild (rms = ~1 nm). On the other hand, UV initiation on silicon totally reversed the chemical linkages to predominantly Si-C without further compromising the surface roughness, highlighting the importance of surface radicals determining the reactivity of the silicon surface to the selected alkynes.

  2. XPS and FTIR investigation of the surface properties of different prepared titania nano-powders

    DEFF Research Database (Denmark)

    Jensen, Henrik; Solovyev, Alexey; Lie, Zheshen

    2005-01-01

    Surface studies of nano-sized TiO2 powders prepared by different methods showed that the preparation method had great impact on the surface properties. XPS measurements showed that the oxygen composition was related to the preparation method. The chloride method yielded the lowest amount of surface...... oxygen (29%) and sol–gel prepared powder showed the greatest amount of surface oxygen (66%) in the form of surface hydroxyl groups. The remaining oxygen was identified as lattice oxygen. The powder prepared by the sol–gel method contained carbon impurities originating from residual alkoxy groups....... Supercritical sol–gel prepared powder and powder prepared by the sulphate method revealed same trends regarding oxygen composition with 44–47% being surface oxygen; neither contained carbon impurities. The results obtained from XPS were confirmed by FTIR measurements....

  3. Facile method to fabricate raspberry-like particulate films for superhydrophobic surfaces.

    Science.gov (United States)

    Tsai, Hui-Jung; Lee, Yuh-Lang

    2007-12-04

    A facile method using layer-by-layer assembly of silica particles is proposed to prepare raspberry-like particulate films for the fabrication of superhydrophobic surfaces. Silica particles 0.5 microm in diameter were used to prepare a surface with a microscale roughness. Nanosized silica particles were then assembled on the particulate film to construct a finer structure on top of the coarse one. After surface modification with dodecyltrichlorosilane, the advancing and receding contact angles of water on the dual-sized structured surface were 169 and 165 degrees , respectively. The scale ratio of the micro/nano surface structure and the regularity of the particulate films on the superhydrophobic surface performance are discussed.

  4. Cooperative doping effects of Ti and nano-SiC on transport critical current density and grain connectivity of in situ MgB{sub 2} tapes

    Energy Technology Data Exchange (ETDEWEB)

    Pan, X.F., E-mail: PAN.Xifeng@nims.go.jp [National Institute for Materials Science, Superconducting Materials Research Center, 1-2-1, Sengen, Tsukuba, Ibaraki 305-0047 (Japan)] [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Southwest Jiaotong University, Chengdu 610031 (China); Matsumoto, A.; Kumakura, H. [National Institute for Materials Science, Superconducting Materials Research Center, 1-2-1, Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Cheng, C.H.; Zhao, Y. [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Southwest Jiaotong University, Chengdu 610031 (China)] [School of Materials Science and Engineering, University of New South Wales, Sydney 2052, NSW (Australia)

    2011-11-15

    We studied the cooperative doping effects of Ti and nano-SiC on transport J{sub c} and grain connectivity of MgB{sub 2} tape. Ti doping significantly weakens the current dependence of T{sub c} of MgB{sub 2} tapes at self-field, and does not change T{sub c} or slightly increases T{sub c}. Further Ti adding can enhance in-field J{sub c} performance of SiC doped MgB{sub 2} tapes by a factor of 50-100% at 4.2 K and 10 T. Ti addition improves the J{sub c} performance of undoped and SiC doped MgB{sub 2} by modifying their grains connection. By now, nano-SiC powder (20-30 nm) is still the most effective additive for improving upper critical field and critical current density of MgB{sub 2}-based superconducting materials. However, some decomposed carbon aggregates at grain boundaries and results in serious weak-links of MgB{sub 2} grains, and these weak-links limit the further improvement of critical current density, J{sub c} of MgB{sub 2}, especially at lower fields. Ti doping is reported to increase the compactness of MgB{sub 2}, and modify its intergranular coupling by forming ultrathin TiB{sub 2} layer at grain boundaries. In this work, we studied the cooperative doping effects of Ti and nano-SiC on transport J{sub c} and grain connectivity of MgB{sub 2} and the possibility to improve transport J{sub c} of SiC doped MgB{sub 2} by introducing Ti additive. The results suggest the Ti addition can obviously improve J{sub c} of MgB{sub 2} at lower fields and also enhance the J{sub c} of SiC doped MgB{sub 2} by improving their grain connectivity which shows serious intergranular weak-links.

  5. Nanoimprint Lithography on curved surfaces prepared by fused deposition modelling

    International Nuclear Information System (INIS)

    Köpplmayr, Thomas; Häusler, Lukas; Bergmair, Iris; Mühlberger, Michael

    2015-01-01

    Fused deposition modelling (FDM) is an additive manufacturing technology commonly used for modelling, prototyping and production applications. The achievable surface roughness is one of its most limiting aspects. It is however of great interest to create well-defined (nanosized) patterns on the surface for functional applications such as optical effects, electronics or bio-medical devices. We used UV-curable polymers of different viscosities and flexible stamps made of poly(dimethylsiloxane) (PDMS) to perform Nanoimprint Lithography (NIL) on FDM-printed curved parts. Substrates with different roughness and curvature were prepared using a commercially available 3D printer. The nanoimprint results were characterized by optical light microscopy, profilometry and atomic force microscopy (AFM). Our experiments show promising results in creating well-defined microstructures on the 3D-printed parts. (paper)

  6. Broadband electron spin resonance in a nanosized La{sub 0.25}Ca{sub 0.75}MnO{sub 3} manganite

    Energy Technology Data Exchange (ETDEWEB)

    Fernàndez-Martínez, Antoni; García-Santiago, Antoni, E-mail: agarciasan@ub.edu; Hernàndez, Joan Manel [Grup de Magnetisme, Departament de Física Fonamental, Facultat de Física, Universitat de Barcelona, Martí i Franquès 1, planta 4, 08028 Barcelona (Spain); Institut de Nanociència i Nanotecnologia IN2UB, Universitat de Barcelona, Martí i Franquès 1, planta 3, edifici nou, 08028 Barcelona (Spain); Zhang, Tao [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China)

    2014-08-07

    The microwave response of a nanogranular La{sub 0.25}Ca{sub 0.75}MnO{sub 3} manganite has been studied by means of broadband electron spin resonance experiments performed in a commercial magnetic properties measurement system magnetometer using two purpose-built probes. The results concur with the hydrodynamic model for spin-glass systems and allow to determine the gyromagnetic ratio and the effective uniaxial magnetic anisotropy constant in a wide range of temperatures. The thermal behavior of both magnitudes provides information about structural transitions and magnetic interactions within the nanosized grains that make the sample. The experiments enable to corroborate the validity of the applied model in this kind of magnetic systems.

  7. Microstructure and Mechanical Performance of Cu-Sn-Ti-Based Active Braze Alloy Containing In Situ Formed Nano-Sized TiC Particles

    Science.gov (United States)

    Leinenbach, Christian; Transchel, Robert; Gorgievski, Klea; Kuster, Friedrich; Elsener, Hans Rudolf; Wegener, Konrad

    2015-05-01

    A Cu-Sn-Ti-based active brazing filler alloy was in situ reinforced with nanosized TiC particles by adding different amounts of a cellulose nitride-based binder. The TiC particles emanate from a reaction of the Ti within the filler alloy with the carbon from the binder that does not decompose completely during heating. The correlation between the microstructure and mechanical performance was studied. In addition, the effect of different binder amounts on the shear strength and cutting performance of brazed diamond grains was studied in shear tests and single grain cutting tests. The results clearly show that the mechanical performance of the brazed diamond grains can be improved by the formation of TiC particles. This is attributed to particle strengthening of the filler alloy matrix as well as to the decreasing grain size and more homogeneous distribution of the (Cu,Sn)3Ti5 phase with increasing amount of binder.

  8. Preparation and Characterization of Nanosized Bi-Doped SnO₂/Reduced Graphene Oxide 3D Hybrids for Visible-Light-Driven Photocatalysis.

    Science.gov (United States)

    Wu, Xiang-Feng; Zhang, Chen-Xu; Sun, Yang; Fu, Shi-Da; Li, Hui; Wang, Yi-Jin; Zhang, Jia-Rui; Su, Jun-Zhang; Wang, Yi-Wei; Wang, Kai-Yuan

    2018-07-01

    The nanosized Bi-doped SnO2/reduced graphene oxide 3D hybrids have been synthesized via one-step hydrothermal method. The structures, morphologies, photocatalytic activities of the as-prepared samples were discussed, respectively. The formation mechanism of the as-prepared hybrids was also proposed. Experimental results indicated that the usage amount of Bi2Sn2O7 obviously affected the photocatalytic performance of the as-prepared products. When it was 450 mg, the as-prepared sample possessed the band gap energy of 1.9 eV and the photocatalytic efficiency of 90% in 210 min for degradation of rhodamine B solution. In addition, triethylene tetramine and the as-prepared carbon hydrogel could act as reductant to synergistically reduce Bi2Sn2O7 into Bi-doped SnO2 particles during the formation of the hybrids.

  9. One step aqueous solution preparation of nanosize iron-doped tin oxide from SnO{sub 2}.xH{sub 2}O gel

    Energy Technology Data Exchange (ETDEWEB)

    Melghit, Khaled [Chemistry Department, College of Science, P.O. Box 36, Al-Khodh 123, Sultan Qaboos University (Oman)]. E-mail: melghit@squ.edu.om; Bouziane, Khalid [Physics Department, College of Science, P.O. Box 36, Al-Khodh 123, Sultan Qaboos University (Oman)

    2006-03-15

    Nanosized iron-doped tin oxide solid solution was prepared by mixing tin oxide gel SnO{sub 2}.xH{sub 2}O with a boiling solution of iron nitrate. The XRD data of the as-prepared and annealed sample at 773 K show that the patterns are indexed to the rutile phase without any trace of an extra phase. SEM and TEM results performed on different selected area of the samples reveal a homogeneous composition of 8 at.% of Fe content and a size of about 2 nm of the particles. The particles size was found to increase slightly with temperature; about 7 nm after 24 h at 773 K. Structural and magnetic results seem to indicate that Fe{sup 3+} substitute for Sn{sup 4+} on the as-prepared sample. The system presents some weak ferromagnetic character at room temperature.

  10. The use of positron spectroscopy for revealing the nanosized structures in liquid mixtures. Identification of n-propanol nanoagglomerates in aqueous solutions

    Science.gov (United States)

    Stepanov, P. S.; Byakov, V. M.; Zaluzhnyi, A. G.

    2014-04-01

    The potential of positron spectroscopy for identification of nanosized structures in liquid mixtures, which is a difficult problem that still remains a challenge in physical chemistry of liquids, was demonstrated. The water- n-propanol mixtures were chosen as an example. An analysis of the concentration dependences of the mean lifetime of ortho-positronium atoms in water- n-propanol binary mixtures and water-propanol mixtures containing CoCl2 (0.4 M) and Co(ClO4)2 (0.6 M) suggested that the water- n-propanol mixture with ˜0.1 to ˜0.4 mole fractions of propanol resembled an emulsion of alcohol nanodrops suspended in water.

  11. Interaction of NO with nanosized Ru-, Pd-, and Pt-Doped SnO2: electron paramagnetic resonance, Mössbauer, and electrical investigation.

    Science.gov (United States)

    Canevali, Carmen; Mari, Claudio Maria; Mattoni, Mariachiara; Morazzoni, Franca; Nodari, Luca; Ruffo, Riccardo; Russo, Umberto; Scotti, Roberto

    2005-04-21

    The mechanism of NO interaction with nanosized Ru(Pd,Pt)-doped SnO(2) was studied by electron paramagnetic resonance, Mössbauer, and electric resistance measurements. Three steps were proposed for the reaction between the semiconductor oxide and the gaseous component: (i) the formation of bielectronic oxygen vacancies (V(o)) in SnO(2); (ii) their single-ionization (V(o)(*)) with injection of electrons into the SnO(2) conduction band; (iii) the subsequent transfer of electrons from V(o)(*) to [Ru(Pd,Pt)](4+). The last process induces the formation of further oxygen vacancies which reduce the transition metal centers to lower oxidation states; the redox processes is enhanced and the electrical resistance in transition metal-doped SnO(2) is stronger modified with respect to the undoped material.

  12. Engineering and Scaling the Spontaneous Magnetization Reversal of Faraday Induced Magnetic Relaxation in Nano-Sized Amorphous Ni Coated on Crystalline Au

    Science.gov (United States)

    Li, Wen-Hsien; Lee, Chi-Hung; Kuo, Chen-Chen

    2016-01-01

    We report on the generation of large inverse remanent magnetizations in nano-sized core/shell structure of Au/Ni by turning off the applied magnetic field. The remanent magnetization is very sensitive to the field reduction rate as well as to the thermal and field processes before the switching off of the magnetic field. Spontaneous reversal in direction and increase in magnitude of the remanent magnetization in subsequent relaxations over time were found. All of the various types of temporal relaxation curves of the remanent magnetizations are successfully scaled by a stretched exponential decay profile, characterized by two pairs of relaxation times and dynamic exponents. The relaxation time is used to describe the reduction rate, while the dynamic exponent describes the dynamical slowing down of the relaxation through time evolution. The key to these effects is to have the induced eddy current running beneath the amorphous Ni shells through Faraday induction. PMID:28773549

  13. On the generation of surface depressions in polishing polycrystalline diamond compacts

    International Nuclear Information System (INIS)

    Tang, Fengzai; Chen, Yiqing; Zhang, Liangchi

    2014-01-01

    This paper investigates the surface depressions generated during the polishing of the (1 1 1) surfaces of polycrystalline diamond (PCD) compacts when using the dynamic friction polishing (DFP) method. It was found that surface depressions of six-sided faces along octahedral planes were the typical features created by the DFP. Although the size of the well-developed depressions can vary significantly, the rectilinear edges are always aligned with the directions. Pronounced {1 1 1} planar defects (i.e., twins) were revealed underneath a depression apex. The interception of the defect plane with the polished surface accounts for the generation of the aligned depressions and for the discernible asymmetry of the pyramidal faces with respect to the (1 1 1) plane. It was revealed that the attached debris layer on the PCD surfaces contained sp 2 -bounded amorphous carbon and nano-sized crystals. (paper)

  14. Preparation and properties of poly(vinyl alcohol/chitosan blend bionanocomposites reinforced with cellulose nanocrystals/ZnO-Ag multifunctional nanosized filler

    Directory of Open Access Journals (Sweden)

    Azizi S

    2014-04-01

    Full Text Available Susan Azizi,1 Mansor Bin Ahmad,1 Mohd Zobir Hussein,1 Nor Azowa Ibrahim,1 Farideh Namvar2,31Department of Chemistry, Faculty of Science, 2Institute of Tropical Forestry and Forest Products, University Putra Malaysia, Selangor, Malaysia; 3Mashhad Branch, Islamic Azad University, Mashhad, IranAbstract: A series of novel bionanocomposites were cast using different contents of zinc oxide-silver nanoparticles (ZnO-AgNPs stabilized by cellulose nanocrystals (CNC as multifunctional nanosized fillers in poly(vinyl alcohol/chitosan (PVA/Cs matrices. The morphological structure, mechanical properties, ultraviolet-visible absorption, and antimicrobial properties of the prepared films were investigated as a function of their CNC/ZnO-AgNP content and compared with PVA/chitosan/CNC bionanocomposite films. X-ray diffraction and field emission scanning electron microscopic analyses showed that the CNC/ZnO-AgNPs were homogeneously dispersed in the PVA/Cs matrix and the crystallinity increased with increasing nanosized filler content. Compared with pure PVA/Cs, the tensile strength and modulus in the films increased from 0.055 to 0.205 GPa and from 0.395 to 1.20 GPa, respectively. Ultraviolet and visible light can be efficiently absorbed by incorporating ZnO-AgNPs into a PVA/Cs matrix, suggesting that these bionanocomposite films show good visibility and ultraviolet-shielding effects. The bionanocomposite films had excellent antimicrobial properties, killing both Gram-negative Salmonella choleraesuis and Gram-positive Staphylococcus aureus. The enhanced physical properties achieved by incorporating CNC/ZnO-AgNPs could be beneficial in various applications.Keywords: multifunctional nanofiller, bionanocomposite, cellulose nanocrystals, antimicrobial properties, poly(vinyl alcohol/chitosan blend

  15. Nano-sized fluorescent particles as new tracers for sentinel node detection: experimental model for decision of appropriate size and wavelength.

    Science.gov (United States)

    Nakajima, Morio; Takeda, Motohiro; Kobayashi, Masaki; Suzuki, Satoshi; Ohuchi, Noriaki

    2005-06-01

    The concepts of made-to-order and low-invasiveness medicines are becoming widely accepted. A treatment for cancer, with minimum invasive surgery and without lymph nodes dissection based on sentinel lymph node (SN) navigation surgery, would adhere to these concepts. Dyes and/or radioisotopes are employed for SN detection in standard methods, however, each detection method has advantages and disadvantages. To make up for the disadvantages, we aimed at developing a new non-invasive method using fluorescent beads of uniform nano-size that could efficiently visualize SN from outside the body, and conducted experiments to determine the appropriate size and fluorescent wavelength. We examined various bead sizes and fluorescent wavelengths. The sizes were 20, 40, 100 and 200 nm. The fluorescent peak wavelengths of the beads were yellow-green (515 nm), dark red (680 nm), far red (720 nm) and infrared (755 nm). The beads were subcutaneously injected into the foot pad of the hind leg of a rat, and followed by laser scanning of the inguinal area for fluorescence observation. The beads exhibited different times for the fluorescence detection according to their sizes and wavelength. The 40 nm beads were considered to be the most appropriate size for SN detection in rats. The wavelength of near infrared was effective for avoiding attenuation by the tissue. In conclusion, we confirmed that uniformly nano-sized fluorescent beads have the potential to be an alternative to existing tracers in the detection of the SN in animal experiments if we select the appropriate particle size and wavelength.

  16. Characterisation of micro-sized and nano-sized tungsten oxide-epoxy composites for radiation shielding of diagnostic X-rays.

    Science.gov (United States)

    Azman, N Z Noor; Siddiqui, S A; Low, I M

    2013-12-01

    Characteristics of X-ray transmissions were investigated for epoxy composites filled with 2-10 vol% WO3 loadings using synchrotron X-ray absorption spectroscopy (XAS) at 10-40 keV. The results obtained were used to determine the equivalent X-ray energies for the operating X-ray tube voltages of mammography and radiology machines. The results confirmed the superior attenuation ability of nano-sized WO3-epoxy composites in the energy range of 10-25 keV when compared to their micro-sized counterparts. However, at higher synchrotron radiation energies (i.e., 30-40 keV), the X-ray transmission characteristics were similar with no apparent size effect for both nano-sized and micro-sized WO3-epoxy composites. The equivalent X-ray energies for the operating X-ray tube voltages of the mammography unit (25-49 kV) were in the range of 15-25 keV. Similarly, for a radiology unit operating at 40-60 kV, the equivalent energy range was 25-40 keV, and for operating voltages greater than 60 kV (i.e., 70-100 kV), the equivalent energy was in excess of 40 keV. The mechanical properties of epoxy composites increased initially with an increase in the filler loading but a further increase in the WO3 loading resulted in deterioration of flexural strength, modulus and hardness. © 2013.

  17. Effect of zinc-borate glass addition on the thermal properties of the cordierite/Al2O3 composites containing nano-sized spinel crystal.

    Science.gov (United States)

    Jo, Sinae; Kang, Seunggu

    2013-11-01

    Low-melting zinc-borate glass was added to the cordierite/Al2O3 composite in order to improve the sintering facility of Al2O3 and formation of nano-sized spinel crystal of high thermal conductivity. Increasing the ZnO/B2O3 ratio in the zinc-borate glass increased the ZnAl2O4 spinel and decreased the Al4B2O9 crystal peak intensities in X-ray diffraction pattern. The XRD peak intensities of the ZnAl2O4 spinel and Al4B2O9 crystals in the specimen containing 10 wt% zinc-borate glass (10G series) are higher than that of the specimen containing 5 wt% zinc-borate glass (5G series). The microstructures of most 10G series specimens had the flower-shaped crystal which was composed of 50 nm wide and 250 nm long needle-like crystals and identified as ZnAl2O4 spinel phase. The thermal conductivity of the 10G series specimen was higher than that of the 5G series in any ZnO/B2O3 ratio due to the formation of plenty of nano-sized ZnAl2O4 spinel of high thermal conductivity. Particularly, the thermal conductivity of the cordierite/Al2O3 composite containing 10 wt% zinc-borate glass of ZnO/B2O3 weight ratio = 1.5 was 3.8 W/Km which is much higher than that of the published value (3.0 W/Km).

  18. Photocatalytic self-cleaning poly(L-lactide) materials based on a hybrid between nanosized zinc oxide and expanded graphite or fullerene

    Energy Technology Data Exchange (ETDEWEB)

    Virovska, Daniela [Laboratory of Bioactive Polymers, Institute of Polymers, Bulgarian Academy of Sciences, Acad. G. Bonchev St., bl. 103A, BG-1113 Sofia (Bulgaria); Paneva, Dilyana, E-mail: panevad@polymer.bas.bg [Laboratory of Bioactive Polymers, Institute of Polymers, Bulgarian Academy of Sciences, Acad. G. Bonchev St., bl. 103A, BG-1113 Sofia (Bulgaria); Manolova, Nevena [Laboratory of Bioactive Polymers, Institute of Polymers, Bulgarian Academy of Sciences, Acad. G. Bonchev St., bl. 103A, BG-1113 Sofia (Bulgaria); Rashkov, Iliya, E-mail: rashkov@polymer.bas.bg [Laboratory of Bioactive Polymers, Institute of Polymers, Bulgarian Academy of Sciences, Acad. G. Bonchev St., bl. 103A, BG-1113 Sofia (Bulgaria); Karashanova, Daniela [Institute of Optical Materials and Technologies, Bulgarian Academy of Sciences, Acad. G. Bonchev St., bl. 109, BG-1113 Sofia (Bulgaria)

    2016-03-01

    New self-cleaning materials of polymer fibers decorated with a hybrid between nanosized zinc oxide and expanded graphite (EG) or fullerene (C{sub 60}) were obtained. The new materials were prepared by applying electrospinning in conjunction with electrospraying. Poly(L-lactide) (PLA) was selected as a biocompatible and (bio)degradable polymer carrier. PLA solution was electrospun in combination with electrospraying of a suspension that contained the ZnO/EG or ZnO/C{sub 60} hybrid. Mats with different content of EG or C{sub 60} were obtained. The new materials were characterized by scanning and transmission electron microscopy (SEM and TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and X-ray diffraction analysis (XRD). The photocatalytic activity of the materials was evaluated by using model dyes. The formation of a hybrid between ZnO and EG led to enhancement of the photocatalytic activity of the mats at ZnO/EG weight ratios of 90/10 and 85/15. Increase in the photocatalytic activity of the ZnO-containing mats was also achieved by the formation of a hybrid between ZnO and C{sub 60} at a fullerene content of 0.5 and 1.0 wt.% in respect to ZnO weight. The new materials exhibited antibacterial activity as evidenced by the performed studies against Staphylococcus aureus. - Highlights: • New self-cleaning materials are fabricated by electrospinning/electrospraying. • PLA fibers decorated with nanosized ZnO/EG or ZnO/C{sub 60} hybrid are obtained. • Their photocatalytic activity is enhanced as compared to fibers with bare ZnO. • The new materials can be used repeatedly for degradation of MB and RR dyes. • The new self-cleaning materials exhibit antibacterial activity against S. aureus.

  19. Surface nanocrystallization of stainless steel for reduced biofilm adherence

    Energy Technology Data Exchange (ETDEWEB)

    Yu Bin; Li, D Y [Department of Biomedical Engineering, University of Alberta, Edmonton, AB (Canada); Davis, Elisabeth M; Irvin, Randall T [Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB, T6G 2H7 (Canada); Hodges, Robert S [Department of Biochemistry and Molecular Genetics, University of Colorado Health Sciences Center at Fitzsimons, RC1 South Tower, Room 9121, PO Box 6511 MS 8101, Aurora, CO 80045 (United States)], E-mail: dongyang@ualberta.ca

    2008-08-20

    Stainless steel is one of the most common metallic biomedical materials. For medical applications, its resistance to the adherence of biofilms is of importance to the elimination or minimization of bacterial infections. In this study, we demonstrate the effectiveness of a process combining surface nanocrystallization and thermal oxidation (or a recovery heat treatment in air) for reducing the biofilm's adherence to stainless steel. During this treatment, a target surface was sandblasted and the resultant dislocation cells in the surface layer were turned into nanosized grains by a subsequent recovery treatment in air. This process generated a more protective oxide film that blocked the electron exchange or reduced the surface activity more effectively. As a result, the biofilm's adherence to the treated surface was markedly minimized. A synthetic peptide was utilized as a substitute of biofilms to evaluate the adhesion between a treated steel surface and biofilms using an atomic force microscope (AFM) through measuring the adhesive force between the target surface and a peptide-coated AFM tip. It was shown that the adhesive force decreased with a decrease in the grain size of the steel. The corresponding surface electron work function (EWF) of the steel was also measured, which showed a trend of variation in EWF with the grain size, consistent with corresponding changes in the adhesive force.

  20. Bacterial growth on a superhydrophobic surface containing silver nanoparticles

    Science.gov (United States)

    Heinonen, S.; Nikkanen, J.-P.; Laakso, J.; Raulio, M.; Priha, O.; Levänen, E.

    2013-12-01

    The antibacterial effect of silver can be exploited in the food and beverage industry and medicinal applications to reduce biofouling of surfaces. Very small amount of silver ions are enough to destructively affect the metabolism of bacteria. Moreover, superhydrophobic properties could reduce bacterial adhesion to the surface. In this study we fabricated superhydrophobic surfaces that contained nanosized silver particles. The superhydrophobic surfaces were manufactured onto stainless steel as combination of ceramic nanotopography and hydrophobication by fluorosilane. Silver nanoparticles were precipitated onto the surface by a chemical method. The dissolution of silver from the surface was tested in an aqueous environment under pH values of 1, 3, 5, 7, 9, 11 and 13. The pH value was adjusted with nitric acid and ammonia. It was found that dissolution rate of silver increased as the pH of the solution altered from the pH of de-ionized water to lower and higher pH values but dissolution occurred also in de-ionized water. The antimicrobial potential of this coating was investigated using bacterial strains isolated from the brewery equipment surfaces. The results showed that the number of bacteria adhering onto steel surface was significantly reduced (88%) on the superhydrophobic silver containing coating.

  1. Magnetic relaxation phenomena and inter-particle interactions in nanosized gamma-Fe sub 2 O sub 3 systems

    CERN Document Server

    Predoi, D; Tronc, E; Nogues, M; Russo, U; Principi, G; Filoti, G

    2003-01-01

    Samples of gamma-Fe sub 2 O sub 3 nano-particles with a mean size of 4.0(3) nm and with different hydration and surfactant degrees were prepared by sol-gel methods. Morphology and structural data were obtained by transmission electron microscopy and x-ray diffraction, whereas the surface effects and hyperfine interactions were analysed mainly by Moessbauer spectroscopy. The relative number of surface iron positions was found to be proportional to the amount of OH sup - and SO sub 4 sup 2 sup - groups on the particle surface, which in turn is strictly dependent on the preparation conditions. Strong relaxation processes versus temperature were evidenced in the analysed systems. New criteria for the evaluation of the blocking temperature via Moessbauer measurements are proposed. The results are in good agreement with blocking temperatures obtained by magnetic measurements. Moreover, it was shown that the inter-particle magnetic interactions decrease with the number of iron surface states.

  2. NMR Spectroscopy of the Hydrated Layer of Composite Particles Based on Nanosized Al2O3 and Vitreous Humor

    Science.gov (United States)

    Turov, V. V.; Gerashchenko, I. I.; Markina, A. I.

    2013-11-01

    The hydrated layer of composite particles prepared using Al2O3 and cattle vitreous humor was investigated using NMR spectroscopy. It was found that water bound to Al2O3 nanoparticles was present in the form of clusters with different degrees of association and energies of interaction with the surface. Water bound to the surface of the Al2O3/vitreous humor composite became more uniform upon immobilization of vitreous humor components on the surface of the Al2O3. With this, the clusters of adsorbed water had characteristics that were close to those found in air and weakly polar CHCl3 media. Addition of polar CH3CN led to the formation of very small water clusters. PMR spectra of the surface of the Al2O3/vitreous humor composite in the presence of trifluoroacetic acid differentiated four types of hydrated structures that differed in the degree of water association.

  3. Three-Dimensional Porous Particles Composed of Curved, Two-Dimensional, Nano-Sized Layers for Li-Ion Batteries

    Science.gov (United States)

    Yushin, Gleb; Evanoff, Kara; Magasinski, Alexander

    2012-01-01

    Thin Si films coated on porous 3D particles composed of curved 2D graphene sheets have been synthesized utilizing techniques that allow for tunable properties. Since graphene exhibits specific surface area up to 100 times higher than carbon black or graphite, the deposition of the same mass of Si on graphene is much faster in comparison -- a factor which is important for practical applications. In addition, the distance between graphene layers is tunable and variation in the thickness of the deposited Si film is feasible. Both of these characteristics allow for optimization of the energy and power characteristics. Thicker films will allow higher capacity, but slower rate capabilities. Thinner films will allow more rapid charging, or higher power performance. In this innovation, uniform deposition of Si and C layers on high-surface area graphene produced granules with specific surface area (SSA) of 5 sq. m/g.

  4. Nano-objects as biomaterials: immense opportunities, significant challenges and the important use of surface analytical methods

    Energy Technology Data Exchange (ETDEWEB)

    Baer, Donald R.; Shutthanandan, Vaithiyalingam

    2017-05-30

    Nano-sized objects are increasingly important as biomaterials and their surfaces play critical roles in determining their beneficial or deleterious behaviors in biological systems. Important characteristics of nanomaterials that impact their application in many areas are described with a strong focus on the importance of particle surfaces and surface characterization. Understanding aspects of the inherent nature of nano-objects and the important role that surfaces play in these applications is a universal need for any research or product development using such materials in biological applications. The role of surface analysis methods in collecting critical information about the nature of particle surfaces and physicochemical properties of nano-objects is described along with the importance of including sample history and analysis results in a record of provenance information regarding specific batches of nano-objects.

  5. TiO2 Surface Coating of Mn-Zn Dopped Ferrites Study

    DEFF Research Database (Denmark)

    Solný, Tomáš; Ptacek, Petr; Másilko, Jiří

    2016-01-01

    This study deals with TiO2 coating of powder Mn-Zn ferrite in order to recieve photocatalytic layer on the top of these particles, forming core-shell catalyst. Powder catalysts are of great advance over the world due to the high surface area, considering the kinetics proceeds through heterogenous...... phase boundary catalysis. However their withdrawal from cleaning systems often requires energetically and economically demanding processes such as filtration and ultrafiltration. Since the ferrite is magnetic, the advantage of such formed core-shell photocatalyst is easibility of removing from...... photocatalytic decomposition system using external magnetic field. In this study the surface coating is performed, using Ti alkoxides mixtures with nanosized TiO2 particles and C and Au coating to form film layer of TiO2 on the surface of ferrite. XRD, SEM – EDS analyses are employed to study surface coating....

  6. Hierarchically structured superhydrophobic coatings fabricated by successive Langmuir-Blodgett deposition of micro-/nano-sized particles and surface silanization.

    Science.gov (United States)

    Tsai, Ping-Szu; Yang, Yu-Min; Lee, Yuh-Lang

    2007-11-21

    The present study demonstrates the creation of a stable, superhydrophobic surface by coupling of successive Langmuir-Blodgett (LB) depositions of micro- and nano-sized (1.5 µm/50 nm, 1.0 µm/50 nm, and 0.5 µm/50 nm) silica particles on a glass substrate with the formation of a self-assembled monolayer of dodecyltrichlorosilane on the surface of the particulate film. Particulate films, in which one layer of 50 nm particles was deposited over one to five sublayers of larger micro-sized particles, with hierarchical surface roughness and superhydrophobicity, were successfully fabricated. Furthermore, the present 'two-scale' (micro- and nano-sized particles) approach is superior to the previous 'one-scale' (micro-sized particles) approach in that both higher advancing contact angle and lower contact angle hysteresis can be realized. Experimental results revealed that the superhydrophobicity exhibited by as-fabricated particulate films with different sublayer particle diameters increases in the order of 0.5 µm>1.0 µm>1.5 µm. However, no clear trend between sublayer number and surface superhydrophobicity could be discerned. An explanation of superhydrophobicity based on the surface roughness introduced by two-scale particles is also proposed.

  7. Nanostructured surface enhanced Raman scattering substrates for explosives detection

    DEFF Research Database (Denmark)

    Schmidt, Michael Stenbaek; Olsen, Jesper Kenneth; Boisen, Anja

    2010-01-01

    Here we present a method for trace detection of explosives in the gas phase using novel surface enhanced Raman scattering (SERS) spectroscopy substrates. Novel substrates that produce an exceptionally large enhancement of the Raman effect were used to amplify the Raman signal of explosives...... molecules adsorbed onto the substrate. The substrates were fabricated in a cleanroom process which only requires two steps to produce well controlled nano-sized high aspect ratio metal pillars. These substrates had superior chemical sensing performance in addition to a more cost effective fabrication...... process compared to existing commercial substrates. Therefore it is believed that these novel substrates will be able to make SERS more applicable in mobile explosives detection systems to be deployed in for example landmine clearance actions....

  8. Structural elucidation and magnetic behavior evaluation of rare earth (La, Nd, Gd, Tb, Dy) doped BaCoNi-X hexagonal nano-sized ferrites

    Energy Technology Data Exchange (ETDEWEB)

    Majeed, Abdul, E-mail: abdulmajeed2276@gmail.com [Department of Physics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Khan, Muhammad Azhar, E-mail: azhar.khan@iub.edu.pk [Department of Physics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Raheem, Faseeh ur; Hussain, Altaf; Iqbal, F. [Department of Physics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Murtaza, Ghulam [Centre for Advanced Studies in Physics, Government College University, Lahore 54000 (Pakistan); Akhtar, Majid Niaz [Department of Physics, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Shakir, Imran [Deanship of Scientific Research, College of Engineering, King Saud University, PO Box 800, Riyadh 11421 (Saudi Arabia); Warsi, Muhammad Farooq [Department of Chemistry, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan)

    2016-06-15

    Rare-earth (RE=La{sup 3+}, Nd{sup 3+}, Gd{sup 3+}, Tb{sup 3+}, Dy{sup 3+}) doped Ba{sub 2}NiCoRE{sub x}Fe{sub 28−x}O{sub 46} (x=0.25) hexagonal ferrites were synthesized for the first time via micro-emulsion route, which is a fast chemistry route for obtaining nano-sized ferrite powders. These nanomaterials were investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), as well as vibrating sample magnetometer (VSM). The XRD analysis exhibited that all the samples crystallized into single X-type hexagonal phase. The crystalline size calculated by Scherrer's formula was found in the range 7–19 nm. The variations in lattice parameters elucidated the incorporation of rare-earth cations in these nanomaterials. FTIR absorption spectra of these X-type ferrites were investigated in the wave number range 500–2400 cm{sup −1.} Each spectrum exhibited absorption bands in the low wave number range, thereby confirming the X-type hexagonal structure. The enhancement in the coercivity was observed with the doping of rare-earth cations. The saturation magnetization was lowered owing to the redistribution of rare-earth cations on the octahedral site (3b{sub VI}). The higher values of coercivity (664–926 Oe) of these nanomaterials suggest their use in longitudinal recording media. - Graphical abstract: Nano-sized rare-earth (RE=La{sup 3+}, Nd{sup 3+}, Gd{sup 3+}, Tb{sup 3+}, Dy{sup 3+}) doped Ba{sub 2}NiCoRE{sub x}Fe{sub 28−x}O{sub 46} (x=0.25) hexagonal ferrites were synthesized for the first time via micro-emulsion route and the crystallite size was found in the range 7–19 nm. The enhancement in the coercivity was observed with the doping of rare-earth cations. The higher values of coercivity (664–926 Oe) of these nanomaterials suggest their use in longitudinal recording media. - Highlights: • Micro-emulsion route was used to synthesize Ba{sub 2}NiCoRE{sub x}Fe{sub 28−x}O{sub 46} ferrites. • The crystallite size was found

  9. Hybrid zero valent iron (ZVI)/H2O2oxidation process for landfill leachate treatment with novel nanosize metallic calcium/iron composite.

    Science.gov (United States)

    Lee, Son Dong; Mallampati, Srinivasa Reddy; Lee, Byoung Ho

    2017-04-01

    A novel nanosize metallic calcium/iron dispersed reagent was synthesized and tested as coagulant/catalyst in a hybrid zero valent iron (ZVI)/H 2 O 2 oxidation process to treat leachate. Two different types of leachates, one from municipal solid waste (MSW) tipping hall (MSWIL) and second from an MSW landfill site (MSWLL), were collected and characterized. The morphology, elemental composition, and mineral phases of the nano-Ca/CaO and nano-Fe/Ca/CaO were characterized by scanning electron microscopy-electron dispersive spectroscopy (SEM-EDS) and x-ray powder diffraction (XRD) analysis. The coagulation process with 2.5 g L -1 nano-Ca/CaO attained 64.0, 56.0, and 20.7% removal of color, chemical oxygen demand (COD), and total suspended solids (TSS) in MSWLL. With only 1.0 g L -1 of nano-Fe/Ca/CaO, relatively high color, COD and TSS removal was achieved in MSWLL at 67.5, 60.2, and 37.7%, respectively. The heavy metal removal efficiency reached 91-99% after treatment with nano-Fe/Ca/CaO in both leachate samples. The coupling process, using 1.0 g L -1 of nano-Fe/Ca/CaO and 20 mM H 2 O 2 doses, achieved enhancement removal of color, COD, and TSS, up to 95%, 96%, and 66%, respectively, without initial pH control. After this treatment, the color, COD, TSS, and heavy metals were significantly decreased, fitting the Korean discharge regulation limit. A hybrid coupled zero valent iron (ZVI)/H 2 O 2 oxidation process with novel nanosized metallic calcium/iron dispersed reagent proved to be a suitable treatment for dealing with leachate samples. Conventional treatments (biological or physicochemical) are not sufficient anymore to reach the level of purification needed to fully reduce the negative impact of landfill leachates on the environment. This implies that new treatment alternatives species must be proposed. A coupled zero valent iron (ZVI)/H 2 O 2 oxidation process proved to be a suitable treatment for dealing with leachate samples. Coagulation with nFe/Ca/CaO allows 91

  10. Detection of nanoparticles in Dutch surface waters.

    Science.gov (United States)

    Peters, Ruud J B; van Bemmel, Greet; Milani, Nino B L; den Hertog, Gerco C T; Undas, Anna K; van der Lee, Martijn; Bouwmeester, Hans

    2018-04-15

    Nano-enabled consumer products are a likely source of nanoparticles in the environment and a number of studies have shown the release of nanoparticles from commercial products. Predicted environmental concentrations have been calculated but there is a need for real measurement data to validate these calculations. However, the detection of engineered nanoparticles in environmental matrices is challenging because of the low predicted environmental concentrations which may be in the ng/L range. In this study nanosized Ag, CeO 2 and TiO 2 have been measured in multiple surface water samples collected along the rivers Meuse and IJssel in the Netherlands using single-particle ICP-MS as measurement technique. Validation of the analytical method showed its capability to quantitatively determine nanoparticles at low concentrations. Concentration mass detection limits for Ag, CeO 2 and TiO 2 were 0.1ng/L, 0.05ng/L and 10ng/L respectively. Size detection limits for Ag, CeO 2 and TiO 2 were 14, 10 and 100nm. The results of the study confirm the presence of nano-sized Ag and CeO 2 particles and micro-sized TiO 2 particles in these surface waters. n-Ag was present in all samples in concentrations ranging from 0.3 to 2.5ng/L with an average concentration of 0.8ng/L and an average particle size of 15nm. n-CeO 2 was found in all samples with concentrations ranging from 0.4 to 5.2ng/L with an average concentration of 2.7ng/L and an average particle size of 19nm. Finally, μ-TiO 2 was found in all samples with a concentration ranging from 0.2 to 8.1μg/L with an average concentration of 3.1μg/L and an average particle size of 300nm. The particle sizes that were found are comparable with the particle sizes that are used in nanomaterial applications and consumer products. The nanoparticle concentrations confirm the predicted environmental concentrations values in water for all three nanoparticles. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Cobalt and sulfur co-doped nano-size TiO2 for photodegradation of various dyes and phenol

    KAUST Repository

    Siddiqa, Asima

    2015-11-01

    Various compositions of cobalt and sulfur co-doped titania nano-photocatalyst are synthesized via sol–gel method. A number of techniques including X-ray diffraction (XRD), ultraviolet–visible (UV–Vis), Rutherford backscattering spectrometry (RBS), thermal gravimetric analysis (TGA), Raman, N2 sorption, electron microscopy are used to examine composition, crystalline phase, morphology, distribution of dopants, surface area and optical properties of synthesized materials. The synthesized materials consisted of quasispherical nanoparticles of anatase phase exhibiting a high surface area and homogeneous distribution of dopants. Cobalt and sulfur co-doped titania demonstrated remarkable structural and optical properties leading to an efficient photocatalytic activity for degradation of dyes and phenol under visible light irradiations. Moreover, the effect of dye concentration, catalyst dose and pH on photodegradation behavior of environmental pollutants and recyclability of the catalyst is also examined to optimize the activity of nano-photocatalyst and gain a better understanding of the process.

  12. Design and formulation of nano-sized spray dried Efavirenz-Part 1: Influence of formulation parameters

    CSIR Research Space (South Africa)

    Tshweu, L

    2012-10-01

    Full Text Available schedules, with reduced dosing frequency and increased bio-availability due to the increased surface area of the nano-encapsulated drug. PROPOSED SOLUTION In this work, encapsulation of EFV in PCL will be investigated using a scalable spray drying... C., Taira C., Sosnik A. (2010). Efavirenz-loaded polymeric micelles for pediatric anti-HIV pharmacotherapy with significantly higher oral bioavailability. Nanomedicine; 5 11 ? 23. AIDS kills over 1.5 million people a year globally. Current HIV...

  13. Thermochemotherapy effect of nanosized As2O3/Fe3O4 complex on experimental mouse tumors and its influence on the expression of CD44v6, VEGF-C and MMP-9

    Directory of Open Access Journals (Sweden)

    Zhang Dongsheng

    2009-10-01

    Full Text Available Abstract Background Both thermotherapy and arsenic have been shown to be active against a broad spectrum of cancers. To reduce the limitations of conventional thermotherapy, improve therapeutic anticancer activity, reduce the toxicity of arsenic on normal tissue, and increase tissue-specific delivery, we prepared a nanosized As2O3/Fe3O4 complex (Fe3O4 magnetic nanoparticles encapsulated in As2O3. We assessed the thermodynamic characteristics of this complex and validated the hyperthermia effect, when combined with magnetic fluid hyperthermia (MFH, on xenograft HeLa cells (human cervical cancer cell line in nude mice. We also measured the effect on the expression of CD44v6, VEGF-C, and MMP-9 which were related to cancer and/or metastasis. Results The nanosized As2O3/Fe3O4 particles were approximately spherical, had good dispersibility as evidenced by TEM, and an average diameter of about 50 nm. With different concentrations of the nanosized As2O3/Fe3O4 complex, the correspondingsuspension of magnetic particles could attain a steady temperature ranging from 42°C to 65°C when placed in AMF for 40 min. Thermochemotherapy with the nanosized As2O3/Fe3O4 complex showed a significant inhibitory effect on the mass (88.21% and volume (91.57% of xenograft cervical tumors (p 2O3/Fe3O4 complex significantly inhibited the expression of CD44v6, VEGF-C, and MMP-9 mRNA (p Conclusion As2O3/Fe3O4 complex combined with MFH had is a promising technique for the minimally invasive elimination of solid tumors and may be have anticancerometastasic effect by inhibiting the expression of CD44v6, VEGF-C, and MMP-9.

  14. Preparation of a Nanosized As2O3/Mn0.5Zn0.5Fe2O4 Complex and Its Anti-Tumor Effect on Hepatocellular Carcinoma Cells

    Directory of Open Access Journals (Sweden)

    Jia Zhang

    2009-09-01

    Full Text Available Manganese-zinc-ferrite nanoparticles (Mn0.5Zn0.5Fe2O4, MZF-NPs prepared by an improved co-precipitation method and were characterized by transmission electron microscopy (TEM, X-ray diffraction (XRD and energy dispersive spectrometry (EDS. Then thermodynamic testing of various doses of MZF-NPs was performed in vitro. The cytotoxicity of the Mn0.5Zn0.5Fe2O4 nanoparticles in vitro was tested by the MTT assay. A nanosized As2O3/Mn0.5Zn0.5Fe2O4 complex was made by an impregnation process. The complex’s shape, component, envelop rate and release rate of As2O3 were measured by SEM, EDS and atom fluorescence spectrometry, respectively. The therapeutic effect of nanosized As2O3/Mn0.5Zn0.5Fe2O4 complex combined with magnetic fluid hyperthermia (MFH on human hepatocelluar cells were evaluated in vitro by an MTT assay and flow cytometry. The results indicated that Mn0.5Zn0.5Fe2O4 and nanosized As2O3/Mn0.5Zn0.5Fe2O4 complex were both prepared successfully. The Mn0.5Zn0.5Fe2O4 nanoparticles had powerful absorption capabilities in a high-frequency alternating electromagnetic field, and had strong magnetic responsiveness. Moreover, Mn0.5Zn0.5Fe2O4 didn’t show cytotoxicity in vitro. The therapeutic result reveals that the nanosized As2O3/Mn0.5Zn0.5Fe2O4 complex can significantly inhibit the growth of hepatoma carcinoma cells.

  15. Minimal surfaces

    CERN Document Server

    Dierkes, Ulrich; Sauvigny, Friedrich; Jakob, Ruben; Kuster, Albrecht

    2010-01-01

    Minimal Surfaces is the first volume of a three volume treatise on minimal surfaces (Grundlehren Nr. 339-341). Each volume can be read and studied independently of the others. The central theme is boundary value problems for minimal surfaces. The treatise is a substantially revised and extended version of the monograph Minimal Surfaces I, II (Grundlehren Nr. 295 & 296). The first volume begins with an exposition of basic ideas of the theory of surfaces in three-dimensional Euclidean space, followed by an introduction of minimal surfaces as stationary points of area, or equivalently

  16. Large-area electromagnetic enhancement by a resonant excitation of surface waves on a metallic surface with periodic subwavelength patterns.

    Science.gov (United States)

    Zhang, Xin; Liu, Haitao; Zhong, Ying

    2013-10-07

    We theoretically investigate the electromagnetic enhancement on a metallic surface patterned with periodic subwavelength structures. Fully-vectorial calculations show a large-area electromagnetic enhancement (LAEE) on the surface, which strongly contrasts with the previously reported "hot spots" that occur in specific tiny regions and which relieves the rigorous requirement of the nano-scale location of sample molecules. The LAEE allows for designing more practicable substrates for many enhanced-spectra applications. By building up microscopic models, the LAEE is shown due to a resonant excitation of surface waves that include both the surface plasmon polariton (SPP) and a quasi-cylindrical wave (QCW). The surface waves propagate on the substrate over a long distance and thus greatly enlarge the area of electromagnetic enhancement compared to the nano-sized hot spots caused by localized modes. Gain medium is introduced to further strengthen the large-area surface-wave resonance, with which an enhancement factor (EF) of electric-field intensity up to a few thousands is achieved.

  17. Fabrication of Al5083 surface composites reinforced by CNTs and cerium oxide nano particles via friction stir processing

    Energy Technology Data Exchange (ETDEWEB)

    Hosseini, S.A. [Department of Materials Science and Engineering, Faculty of Engineering, Shahid Chamran University of Ahvaz (Iran, Islamic Republic of); Ranjbar, Khalil, E-mail: k_ranjbar@scu.ac.ir [Department of Materials Science and Engineering, Faculty of Engineering, Shahid Chamran University of Ahvaz (Iran, Islamic Republic of); Dehmolaei, R. [Department of Materials Science and Engineering, Faculty of Engineering, Shahid Chamran University of Ahvaz (Iran, Islamic Republic of); Amirani, A.R. [12th Ghaem Street, Bld. Hashemzadeh, Shahrak Golestan, Tehran (Iran, Islamic Republic of)

    2015-02-15

    Highlights: • Using friction stir processing, an effect of CNTs and CeO{sub 2} reinforcements on mechanical and corrosion properties of Al5083 alloy is reported. • The strength of Al5083 was increased by 42%, its matrix grain size reduced five times, and hardness was doubled by the incorporation of CNTs-CeO{sub 2} mixture in the volume ratio of 75-25 respectively. • Unlike the CNTs, incorporation of nanosized CeO{sub 2} particles resulted in remarkable increase in pitting resistance of the alloy. - Abstract: In the present investigation, friction stir processing (FSP) was utilized to incorporate Multi Walled Carbon Nano Tubes (MWCNT) and nanosized cerium oxide particles into the matrix of Al5083 alloy to form surface reinforced composites. The effect of these nanosized reinforcements either separately or in the combined form, on microstructural modification, mechanical properties and corrosion resistance of FSPed Al5083 surface composites was studied. A threaded cylindrical hardened steel tool was used with the rotation speeds of 600 and 800 rpm and travel speeds of 35 and 45 mm/min and a tilt angle of 5°. Mechanical properties and corrosion resistance of FSPed samples were evaluated and compared with the base alloy. The maximum tensile strength and hardness value were achieved for the hybrid composite containing a mixture of CNTs and cerium oxide in the volume ratio of 75-25, respectively, whereas a significant increase in pitting resistance of the base alloy was obtained when cerium oxide alone was incorporated. The corrosion behavior of the samples was investigated by potentiodynamic polarization tests and assessed in term of pitting potential and passivation range. Microstructural analysis carried out by using optical and electron microscopes showed that reinforcements are well dispersed inside the nugget zone (NZ), and remarkable grain refinement is gained. The study was aimed to fabricate surface composites with improved mechanical properties and

  18. Rumble surfaces

    CSIR Research Space (South Africa)

    National Institute for Transport and Road

    1977-01-01

    Full Text Available Rumble surfaces are intermittent short lengths of coarse-textured road surfacings on which vehicle tyres produce a rumbling sound. used in conjunction with appropriate roadsigns and markings, they can reduce accidents on rural roads by alerting...

  19. Surface thermodynamics

    International Nuclear Information System (INIS)

    Garcia-Moliner, F.

    1975-01-01

    Basic thermodynamics of a system consisting of two bulk phases with an interface. Solid surfaces: general. Discussion of experimental data on surface tension and related concepts. Adsorption thermodynamics in the Gibbsian scheme. Adsorption on inert solid adsorbents. Systems with electrical charges: chemistry and thermodynamics of imperfect crystals. Thermodynamics of charged surfaces. Simple models of charge transfer chemisorption. Adsorption heat and related concepts. Surface phase transitions

  20. Addition of nanoscaled bioinspired surface features: A revolution for bone related implants and scaffolds?

    Science.gov (United States)

    Bruinink, Arie; Bitar, Malak; Pleskova, Miriam; Wick, Peter; Krug, Harald F; Maniura-Weber, Katharina

    2014-01-01

    Our expanding ability to handle the "literally invisible" building blocks of our world has started to provoke a seismic shift on the technology, environment and health sectors of our society. During the last two decades, it has become increasingly evident that the "nano-sized" subunits composing many materials—living, natural and synthetic—are becoming more and more accessible for predefined manipulations at the nanosize scale. The use of equally nanoscale sized or functionalised tools may, therefore, grant us unprecedented prospects to achieve many therapeutic aims. In the past decade it became clear that nano-scale surface topography significantly influences cell behaviour and may, potentially, be utilised as a powerful tool to enhance the bioactivity and/ or integration of implanted devices. In this review, we briefly outline the state of the art and some of the current approaches and concepts for the future utilisation of nanotechnology to create biomimetic implantable medical devices and scaffolds for in vivo and in vitro tissue engineering,with a focus on bone. Based on current knowledge it must be concluded that not the materials and surfaces themselves but the systematic biological evaluation of these new material concepts represent the bottleneck for new biomedical product development based on nanotechnological principles. Copyright © 2013 Wiley Periodicals, Inc., a Wiley Company.

  1. Fabrication of Surface Level Cu/SiCp Nanocomposites by Friction Stir Processing Route

    Directory of Open Access Journals (Sweden)

    Cartigueyen Srinivasan

    2015-01-01

    Full Text Available Friction stir processing (FSP technique has been successfully employed as low energy consumption route to prepare copper based surface level nanocomposites reinforced with nanosized silicon carbide particles (SiCp. The effect of FSP parameters such as tool rotational speed, processing speed, and tool tilt angle on microstructure and microhardness was investigated. Single pass FSP was performed based on Box-Behnken design at three factors in three levels. A cluster of blind holes 2 mm in diameter and 3 mm in depth was used as particulate deposition technique in order to reduce the agglomeration problem during composite fabrication. K-type thermocouples were used to measure temperature histories during FSP. The results suggest that the heat generation during FSP plays a significant role in deciding the microstructure and microhardness of the surface composites. Microstructural observations revealed a uniform dispersion of nanosized SiCp without any agglomeration problem and well bonded with copper matrix at different process parameter combinations. X-ray diffraction study shows that no intermetallic compound was produced after processing. The microhardness of nanocomposites was remarkably enhanced and about 95% more than that of copper matrix.

  2. Nano-sized Fe-metal catalyst on ZnO-SiO2: (photo-assisted deposition and impregnation) Synthesis routes and nanostructure characterization

    International Nuclear Information System (INIS)

    Mohamed, R.M.; Al-Rayyani, M.A.; Baeissa, E.S.; Mkhalid, I.A.

    2011-01-01

    Highlights: → We prepared Fe/ZnO-SiO 2 by two methods. → We tested photocatalytic activity for degradation of methylene blue dye. → We controlled band gap and size. → We found activity of Fe/ZnO-SiO 2 prepared by PAD is hightest photocatalytic activity. - Abstract: A nano-sized Fe metal on ZnO-SiO 2 was synthesized using the photo-assisted deposition (PAD) and impregnation routes. The obtained samples were characterized by a series of techniques including X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy, N 2 adsorption, extended X-ray absorption fine structure (EXAFS), and transmission electron microscopy (TEM). Photocatalytic reactivity using Fe-ZnO-SiO 2 catalysts under visible-light condition on the degradation of methylene blue dye was evaluated. The results of characterization reveal, a notable photocatalytic activity of PAD:Fe-ZnO-SiO 2 which was about 9 and 12 times higher than that of Img:Fe-ZnO-SiO 2 and ZnO-SiO 2 , respectively.

  3. Dietary Nanosized Lactobacillus plantarum Enhances the Anticancer Effect of Kimchi on Azoxymethane and Dextran Sulfate Sodium-Induced Colon Cancer in C57BL/6J Mice.

    Science.gov (United States)

    Lee, Hyun Ah; Kim, Hyunung; Lee, Kwang-Won; Park, Kun-Young

    2016-01-01

    This study was undertaken to evaluate enhancement of the chemopreventive properties of kimchi by dietary nanosized Lactobacillus (Lab.)plantarum (nLp) in an azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced colitis-associated colorectal cancer C57BL/6J mouse model. nLp is a dead, shrunken, processed form of Lab. Plantarum isolated from kimchi that is 0.5-1.0 µm in size. The results obtained showed that animals fed kimchi with nLp (K-nLp) had longer colons and lower colon weights/length ratios and developed fewer tumors than mice fed kimchi alone (K). In addition, K-nLp administration reduced levels of proinflammatory cytokine serum levels and mediated the mRNA and protein expressions of inflammatory, apoptotic, and cell-cycle markers to suppress inflammation and induce tumor-cell apoptosis and cell-cycle arrest. Moreover, it elevated natural killer-cell cytotoxicity. The study suggests adding nLp to kimchi could improve the suppressive effect of kimchi on AOM/DSS-induced colorectal cancer. These findings indicate nLp has potential use as a functional chemopreventive ingredient in the food industry.

  4. Structural and magnetic properties of nano-sized NiCuZn ferrites synthesized by co-precipitation method with ultrasound irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Harzali, Hassen, E-mail: harzali@mines-albi.fr [Laboratory of Applied Mineral Chemistry, Faculty of Sciences, University Tunis ElManar, Campus University, Farhat Hached El-Manar, 2092 Tunis (Tunisia); Saida, Fairouz; Marzouki, Arij; Megriche, Adel [Laboratory of Applied Mineral Chemistry, Faculty of Sciences, University Tunis ElManar, Campus University, Farhat Hached El-Manar, 2092 Tunis (Tunisia); Baillon, Fabien; Espitalier, Fabienne [Université de Toulouse, Mines Albi, CNRS, Centre RAPSODEE, Campus Jarlard, F-81013 Albi CT cedex 09 (France); Mgaidi, Arbi [Laboratory of Applied Mineral Chemistry, Faculty of Sciences, University Tunis ElManar, Campus University, Farhat Hached El-Manar, 2092 Tunis (Tunisia); Taibah University, Faculty of Sciences & art, Al Ula (Saudi Arabia)

    2016-12-01

    Sonochemically assisted co-precipitation has been used to prepare nano-sized Ni–Cu–Zn-ferrite powders. A suspension of constituent hydroxides was ultrasonically irradiated for various times at different temperatures with high intensity ultrasound radiation using a direct immersion titanium horn. Structural and magnetic properties were investigated using X-diffraction (XRD), FT-IR spectroscopy, transmission electron microscopy (TEM), Nitrogen adsorption at 77 K (BET) and Vibrating sample magnetometer (VSM). Preliminary experimental results relative to optimal parameters showed that reaction time t=2 h, temperature θ=90 °C and dissipated Power P{sub diss}=46.27 W. At these conditions, this work shows the formation of nanocrystalline single-phase structure with particle size 10–25 nm. Also, ours magnetic measurements proved that the sonochemistry method has a great influence on enhancing the magnetic properties of the ferrite. - Highlights: • Coprecipitation experiments were carried out with ultrasound. • The spinel ferrite NiCuZn was perfectly synthesized by ultrasound. • The saturation magnetization and crystals size are found to be correlated as the dissipated power was varied.

  5. Spectrum designation and effect of Al substitution on the luminescence of Cr3+ doped ZnGa2O4 nano-sized phosphors

    International Nuclear Information System (INIS)

    Zhang Weiwei; Zhang Junying; Chen Ziyu; Wang Tianmin; Zheng Shukai

    2010-01-01

    Low-temperature photoluminescent spectra of ZnGa 2 O 4 :Cr 3+ nano-sized phosphors calcined at different temperatures were reported. The fine structure of the emission spectra has been designated to Cr 3+ ions in different sites including ideal octahedral, Zn-interstitial, Ga ZN 4 -Zn Ga 6 sites and Ga 2 O 3 impurity. The vibronic sidebands for both Stokes' and anti-Stokes' sides are related to the host lattice vibrations, which were confirmed by IR and Raman spectra. Al 3+ is substituted in Ga 3+ sites to form Zn(Ga 1-y Al y ) 2 O 4 :Cr 0.01 3+ (0≤y≤0.5). The blue shift and luminescent intensity variations of the charge transfer band and 3d-3d transitions in the spectra caused by Al substitution were related to larger band gap and stronger crystal field, respectively. The calculated crystal-field parameters indicated that Al incorporation enhanced the crystal field strength and induced more trigonal distortion due to different radii of Al 3+ and Ga 3+ .

  6. Molecular stress responses to nano-sized zero-valent iron (nZVI) particles in the soil bacterium Pseudomonas stutzeri.

    Science.gov (United States)

    Saccà, Maria Ludovica; Fajardo, Carmen; Martinez-Gomariz, Montserrat; Costa, Gonzalo; Nande, Mar; Martin, Margarita

    2014-01-01

    Nanotoxicological studies were performed in vitro using the common soil bacterium Pseudomonas stutzeri to assess the potentially toxic impact of commercial nano-sized zero-valent iron (nZVI) particles, which are currently used for environmental remediation projects. The phenotypic response of P. stutzeri to nZVI toxicity includes an initial insult to the cell wall, as evidenced by TEM micrographs. Transcriptional analyses using genes of particular relevance in cellular activity revealed that no significant changes occurred among the relative expression ratios of narG, nirS, pykA or gyrA following nZVI exposure; however, a significant increase in katB expression was indicative of nZVI-induced oxidative stress in P. stutzeri. A proteomic approach identified two major defence mechanisms that occurred in response to nZVI exposure: a downregulation of membrane proteins and an upregulation of proteins involved in reducing intracellular oxidative stress. These biomarkers served as early indicators of nZVI response in this soil bacterium, and may provide relevant information for environmental hazard assessment.

  7. Phonon-assisted optical bands of nanosized powdery SrAl{sub 2}O{sub 4}:Eu{sup 2+} crystals: Evidence of a multimode Pekarian

    Energy Technology Data Exchange (ETDEWEB)

    Nazarov, M. [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Pulau Pinang (Malaysia); Institute of Applied Physics, Academiei Street 5, Chisinau MD-2028 (Moldova, Republic of); Brik, M.G. [Institute of Physics, University of Tartu, Riia 142, Tartu 51014 (Estonia); Spassky, D. [Institute of Physics, University of Tartu, Riia 142, Tartu 51014 (Estonia); Skobeltsyn Institute of Nuclear Physics, M.V. Lomonosov Moscow State University, 119991 Moscow (Russian Federation); Tsukerblat, B., E-mail: tsuker@bgu.ac.il [Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel); Palii, A. [Institute of Applied Physics, Academiei Street 5, Chisinau MD-2028 (Moldova, Republic of); Nazida, A. Nor [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Pulau Pinang (Malaysia); Faculty of Art and Design, Universiti Teknologi MARA (Perak), Seri Iskandar 32610, Bandar Baru Seri Iskandar, Perak (Malaysia); Ahmad-Fauzi, M.N. [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Pulau Pinang (Malaysia)

    2013-12-09

    A stoichiometric powder composed of nanosized grains of SrAl{sub 2}O{sub 4}:Eu{sup 2+} was synthesized by combustion method at 500 °C with the subsequent calcination at 1000 °C. The zero-phonon line position, parameter of the Stokes shift, heat release factor and effective phonon energy were studied experimentally and analyzed in the framework of the multimode Pekar–Huang–Rhys model. Experimental data show that the optical 4f–5d transitions in Eu{sup 2+} ion exhibit a broad asymmetric electron–vibrational bands with a pronounced structure near the maxima. The form-function of the absorption and luminescence bands are theoretically analyzed in the framework of the model of the linear electron–vibrational interaction assuming strong coupling with the local vibration (estimated Pekar–Huang–Rhys parameter a=2S=10 and frequency ℏω=509 cm{sup −1}) and relatively weak interaction with the crystal phonons. The last results in an effective temperature dependent broadening of the discrete lines corresponding to the local vibrations and to a specific shape of the whole phonon assisted band (multimode Pekarian). Providing specific interrelation between the key parameters the calculated absorption and luminescence bands exhibit peculiar temperature dependent structured peaks in a qualitative agreement with the experimental data.

  8. Chiral resolution of salbutamol in plasma sample by a new chiral ligand-exchange chromatography method after its extraction with nano-sized imprinted polymer.

    Science.gov (United States)

    Alizadeh, Taher; Shamkhali, Amir Naser

    2016-01-15

    A new chromatographic procedure, based upon chiral ligand-exchange principal, was developed for the resolution of salbutamol enantiomers. The separation was carried out on a C18 column. (l)-Alanine and Cu(2+) were applied as chiral resolving agent and complexing ion, respectively. The kind of copper salt had definitive effect on the enantioseparation. Density functional theory (DFT) was used to substantiate the effect of various anions, accompanying Cu(2+), on the formation of ternary complexes, assumed to be created during separation process. The DFT results showed that the anion kind had huge effect on the stability difference between two corresponding diastereomeric complexes and their chemical structures. It was shown that the extent of participation of the chiral selector in the ternary diastereomeric complexes formation was managed by the anion kind, affecting thus the enantioseparation efficiency of the developed method. Water/methanol (70:30) mixture containing (l)-alanine-Cu(2+) (4:1) was found to be the best mobile phase for salbutamol enantioseparation. In order to analyze sulbutamol enantiomers in plasma samples, racemic salbutamol was first extracted from the samples via nano-sized salbutamol-imprinted polymer and then enantioseparated by the developed method. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Nanosized Mesoporous Bioactive Glass/Poly(lactic-co-glycolic Acid Composite-Coated CaSiO3 Scaffolds with Multifunctional Properties for Bone Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Mengchao Shi

    2014-01-01

    Full Text Available It is of great importance to prepare multifunctional scaffolds combining good mechanical strength, bioactivity, and drug delivery ability for bone tissue engineering. In this study, nanosized mesoporous bioglass/poly(lactic-co-glycolic acid composite-coated calcium silicate scaffolds, named NMBG-PLGA/CS, were successfully prepared. The morphology and structure of the prepared scaffolds were characterized by scanning electron microscopy and X-ray diffraction. The effects of NMBG on the apatite mineralization activity and mechanical strength of the scaffolds and the attachment, proliferation, and alkaline phosphatase activity of MC3T3 cells as well as drug ibuprofen delivery properties were systematically studied. Compared to pure CS scaffolds and PLGA/CS scaffolds, the prepared NMBG-PLGA/CS scaffolds had greatly improved apatite mineralization activity in simulated body fluids, much higher mechanical property, and supported the attachment of MC3T3 cells and enhanced the cell proliferation and ALP activity. Furthermore, the prepared NMBG-PLGA/CS scaffolds could be used for delivering ibuprofen with a sustained release profile. Our study suggests that the prepared NMBG-PLGA/CS scaffolds have improved physicochemical, biological, and drug-delivery property as compared to conventional CS scaffolds, indicating that the multifunctional property of the prepared scaffolds for the potential application of bone tissue engineering.

  10. Catalytic Activity of Nanosized CuO-ZnO Supported on Titanium Chips in Hydrogenation of Carbon Dioxide to Methyl Alcohol.

    Science.gov (United States)

    Ahn, Ho-Geun; Lee, Hwan-Gyu; Chung, Min-Chul; Park, Kwon-Pil; Kim, Ki-Joong; Kang, Byeong-Mo; Jeong, Woon-Jo; Jung, Sang-Chul; Lee, Do-Jin

    2016-02-01

    In this study, titanium chips (TC) generated from industrial facilities was utilized as TiO2 support for hydrogenation of carbon dioxide (CO2) to methyl alcohol (CH3OH) over Cu-based catalysts. Nano-sized CuO and ZnO catalysts were deposited on TiO2 support using a co-precipitation (CP) method (CuO-ZnO/TiO2), where the thermal treatment of TC and the particle size of TiC2 are optimized on CO2 conversion under different reaction temperature and contact time. Direct hydrogenation of CO2 to CH3OH over CuO-ZnO/TiO2 catalysts was achieved and the maximum selectivity (22%) and yield (18.2%) of CH3OH were obtained in the range of reaction temperature 210-240 degrees C under the 30 bar. The selectivity was readily increased by increasing the flow rate, which does not affect much to the CO2 conversion and CH3OH yield.

  11. Cationic exchange in nanosized ZnFe2O4 spinel revealed by experimental and simulated near-edge absorption structure

    International Nuclear Information System (INIS)

    Stewart, S. J.; Figueroa, S. J. A.; Ramallo Lopez, J. M.; Requejo, F. G.; Marchetti, S. G.; Bengoa, J. F.; Prado, R. J.

    2007-01-01

    The nonequilibrium cation site occupancy in nanosized zinc ferrites (∼6-13 nm) with different degree of inversion (∼0.2 to 0.4) was investigated using Fe and Zn K-edge x-ray absorption near edge spectroscopy (XANES) and extended x-ray absorption fine structure, and magnetic measurements. The very good agreement between experimental and ab initio calculations on the Zn K-edge XANES region clearly shows the large Zn 2+ (A)→Zn 2+ [B] transference that takes place in addition to the well-identified Fe 3+ [B]→Fe 3+ (A) one, without altering the long-range structural order. XANES spectra features as a function of the spinel inversion were shown to depend on the configuration of the ligand shells surrounding the absorbing atom. This XANES approach provides a direct way to sense cationic inversion in these Zn-containing spinel ferrites. We also demonstrated that a mechanical crystallization takes place on nanocrystalline spinel that causes an increase of both grain and magnetic sizes and, simultaneously, generates a significant augment of the inversion

  12. A study on the thermochemotherapy effect of nanosized As{sub 2}O{sub 3}/MZF thermosensitive magnetoliposomes on experimental hepatoma in vitro and in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Wang Li; Zhang Jia; Wang Ziyu; Liu Jing; Li Yutao; Zhang Dongsheng [School of Medicine, Southeast University, NO. 87 Ding jia qiao, Nanjing 210009 (China); An Yanli, E-mail: wangli040418@163.com, E-mail: zdszds1222@163.com [Affiliated Zhong-Da Hospital of Southeast University, Nanjing 210009 (China)

    2011-08-05

    In this paper, we describe the synthesis and characterization of a nanosized, thermosensitive magnetoliposome encapsulating magnetic nanoparticles (MZFs) and antitumor drugs (As{sub 2}O{sub 3}). The nanoliposomes were spherical and mostly single volume, with an average diameter of 128.2 nm. Differential scanning calorimetry (DSC) showed a liposome phase transition temperature of 42.71 deg. C. After that, we studied the liposomes' anti-hepatoma effect in vitro and in vivo. The antitumor effect of the nanoliposomes on human hepatoma cells, SMMC-7721, and changes in expression of apoptosis-related proteins were examined in vitro. The results show that As{sub 2}O{sub 3}/MZF thermosensitive magnetoliposomes combined with hyperthermia had a great impact on the Bax/Bcl-2 ratio, which increased to 1.914 and exhibited a rapid response to induce apoptosis of tumor cells. An in situ rabbit liver tumor model was established and used to evaluate the antitumor effect of combined hyperthermia and chemotherapy following transcatheter arterial embolization with As{sub 2}O{sub 3}/MZF thermosensitive magnetoliposomes. The results demonstrated a strong anti-hepatoma effect, with a tumor volume inhibition rate of up to 85.22%. Thus, As{sub 2}O{sub 3}/MZF thermosensitive magnetoliposomes may play a great role in the treatment of hepatocarcinoma.

  13. A study on the thermochemotherapy effect of nanosized As2O3/MZF thermosensitive magnetoliposomes on experimental hepatoma in vitro and in vivo

    Science.gov (United States)

    Wang, Li; Zhang, Jia; An, Yanli; Wang, Ziyu; Liu, Jing; Li, Yutao; Zhang, Dongsheng

    2011-08-01

    In this paper, we describe the synthesis and characterization of a nanosized, thermosensitive magnetoliposome encapsulating magnetic nanoparticles (MZFs) and antitumor drugs (As2O3). The nanoliposomes were spherical and mostly single volume, with an average diameter of 128.2 nm. Differential scanning calorimetry (DSC) showed a liposome phase transition temperature of 42.71 °C. After that, we studied the liposomes' anti-hepatoma effect in vitro and in vivo. The antitumor effect of the nanoliposomes on human hepatoma cells, SMMC-7721, and changes in expression of apoptosis-related proteins were examined in vitro. The results show that As2O3/MZF thermosensitive magnetoliposomes combined with hyperthermia had a great impact on the Bax/Bcl-2 ratio, which increased to 1.914 and exhibited a rapid response to induce apoptosis of tumor cells. An in situ rabbit liver tumor model was established and used to evaluate the antitumor effect of combined hyperthermia and chemotherapy following transcatheter arterial embolization with As2O3/MZF thermosensitive magnetoliposomes. The results demonstrated a strong anti-hepatoma effect, with a tumor volume inhibition rate of up to 85.22%. Thus, As2O3/MZF thermosensitive magnetoliposomes may play a great role in the treatment of hepatocarcinoma.

  14. Enhanced performance of nano-sized SiC reinforced Al metal matrix nanocomposites synthesized through microwave sintering and hot extrusion techniques

    Directory of Open Access Journals (Sweden)

    M. Penchal Reddy

    2017-10-01

    Full Text Available In the present study, nano-sized SiC (0, 0.3, 0.5, 1.0 and 1.5 vol% reinforced aluminum (Al metal matrix composites were fabricated by microwave sintering and hot extrusion techniques. The structural (XRD, SEM, mechanical (nanoindentation, compression, tensile and thermal properties (co-efficient of thermal expansion-CTE of the developed Al-SiC nanocomposites were studied. The SEM/EDS mapping images show a homogeneous distribution of SiC nanoparticles into the Al matrix. A significant increase in the strength (compressive and tensile of the Al-SiC nanocomposites with the addition of SiC content is observed. However, it is noticed that the ductility of Al-SiC nanocomposites decreases with increasing volume fraction of SiC. The thermal analysis indicates that CTE of Al-SiC nanocomposites decreases with the progressive addition of hard SiC nanoparticles. Overall, hot extruded Al 1.5 vol% SiC nanocomposites exhibited the best mechanical and thermal performance as compared to the other developed Al-SiC nanocomposites. Keywords: Al-SiC nanocomposites, Microwave sintering, Hot extrusion, Mechanical properties, Thermal expansion

  15. SYNTHESIS AND SPECTRA CHARACTERIZATION OF CoxZn1-xAl2O4 NANOSIZED PIGMENTS BY GEL COMBUSTION METHOD

    Directory of Open Access Journals (Sweden)

    M. CHADORBAFZADEH

    2012-12-01

    Full Text Available Nano sized pigments with the general formula CoxZn1-xAl2O4 (x = 0, 0.2, 0.4, 0.6, 0.8, 1 were synthesized using chlorides by gel combustion method at 700, 800, 900, 1000, 1100°C. DTA/TG, XRD, UV-Vis. and SEM were used to characterize the samples. The DTA results revealed that the formation of the spinel phase occurred at 600 to 670°C. XRD results showed that all the samples, except those treated at 1000 and 1100°C, were constituted of only one phase. The ones treated at 1000 and 1100°C showed extra peaks related to Al2O3. The cobalt containing samples showed a low reflection in the range of 540 to 630 nm, corresponding to the absorption of the colors yellow and orange. Therefore, the cobalt containing samples demonstrated diverse blue colors. The results also revealed that by increasing the cobalt content, the crystallite size decreased from 32 to 9 nm, while by the rise in heat treatment temperature it decreased from 17 to 26. The SEM micrographs revealed the formation of nanosized pigments, with some degree of agglomeration.

  16. Short communication: investigating the effect of saffron (Crocus sativus L.) nano-sizing on its colour extraction efficiency: a preliminary study.

    Science.gov (United States)

    Abootalebian, Mehrdad; Karbasi, Maryam; Sadeghi, Maliheh; Abdinian, Mahnaz; Polikarpov, Igor

    2017-10-01

    This study investigated the effect of saffron nano-sizing on its the colour extraction yield. The whole stigma was ball-milled at three different times (10, 20 and 100 h), immediately or with a 24 h delay was submitted to absorption test, and then the colour extraction efficiency was determined. When stigma was milled for 100 h, its particle size was reduced to less than 20 nm, as shown by SEM and TEM images, and its extraction efficiency was considerably increased by 19.8% as compared with the stigma blended for 10 min. However with a 24 h delay between the end of milling and absorption test, the yield of colour extraction significantly decreased. The recommended milling conditions resulting in extraction efficiency of 16.2% (in comparison with stigma blended for 10 min) were determined to be the milling for 10 h with initial tendering prior to milling operation.

  17. Effect of Different Nano-Sized Silica Sols as Supports on the Structure and Properties of Cu/SiO2 for Hydrogenation of Dimethyl Oxalate

    Directory of Open Access Journals (Sweden)

    Chuancai Zhang

    2017-02-01

    Full Text Available Cu/x-SiO2 catalysts with 4, 10, and 20 nm silica sols as supports was produced by ammonia evaporation method and characterized. Different nano-sized silica sols as supports significantly affected the structure and catalytic properties of the copper catalysts for ethylene glycol synthesis from dimethyl oxalate. Compared with Cu/20-SiO2 and Cu/4-SiO2 catalysts, the catalytic performance and stability of Cu/10-SiO2 catalyst were greatly enhanced. The Cu/10-SiO2 catalyst showed 99.9% conversion with 94% EG selectivity and a lifetime of over 3080 h if it is calculated by industrial weight liquid hourly space velocity (WLHSV of 0.5 h−1. The Cu/10-SiO2 catalyst has one of the longest lifetimes among the catalysts and is a good alternative catalyst for this reaction. Improvement in the catalytic performance and stability of Cu/10-SiO2 is attributed to the proper SBET, Dp and larger dispersion of copper. In addition, the supports of Cu/10-SiO2 catalyst have smaller particles than that of Cu/20-SiO2; thus, the migration and growth of copper species in catalysts are restrained during the reaction.

  18. The influence of pH and reaction time on the formation of FeSe{sub 2} upon selenite reduction by nano-sized pyrite-greigite

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Mingliang [Sun Yat-sen Univ., Zhuhai (China). Sino-French Institute of Nuclear Engineering and Technology; Bardelli, Fabrizio; Ma, Bin; Charlet, Laurent [Grenoble Univ. (France). Environmental Geochemistry Group; Chen, Fanrong; Yang, Yongqiang [Chinese Academy of Sciences, Guangzhou (China). Key Laboratory of Mineralogy and Metallogeny; Chinese Academy of Sciences, Guangzhou (China). Guangdong Provincial Key Laboratory of Mineral Physics and Materials

    2016-11-01

    The influence of pH and reaction time on the formation of FeSe{sub 2} by reductive precipitation of Se(IV) with nano-sized pyrite-greigite was investigated. Reductive precipitation is an effective method of attenuating the mobility of {sup 79}Se, which is foreseen to be a dangerous radioisotope for the geological disposal of high-level radioactive waste (HLW). The results indicated that Se(0)was formed at pH <4.05, whereas, at pH > 6.07, considerable amount of FeSe{sub 2} was formed along with Se(0). These observations are in agreement with the thermodynamic predictions reported in this work. Furthermore, the formation of FeSe{sub 2} was found to continue by increasing the reaction time, indicating that the Se(0) formed in the early reaction stage is gradually transformed to FeSe{sub 2} upon the depletion of aqueous Se(IV). Since FeSe{sub 2} has a stronger reactivity than pyrite, it was proposed that greigite, rather than pyrite, was responsible for the formation of FeSe{sub 2}. The findings in this study are of interest for key geochemical processes governing the mobility of toxic {sup 79}Se in the environment in presence of iron sulfides.

  19. New Surface Properties in Porcelain Gres Tiles with a Look to Human and Environmental Safety

    Directory of Open Access Journals (Sweden)

    C. L. Bianchi

    2012-01-01

    Full Text Available Traditional photocatalysis is here brought forward for both the use of nanosized TiO2 crystallites and the possibility to have a release of TiO2 particles during the final use of the manufactured products. In the present paper both the preparation and characterization of a new generation of photocatalytic tiles are presented. The originality of these products is the surface presence of microsized TiO2 as it is not clear yet the impact of the nanoparticles on both human and environmental safety. TiO2 is here mixed with a silica compound and the final thermal treatment at 680°C allows the complete surface vitrification which, in turn, makes the tiles surface strongly resistant to abrasion. Photocatalytic efficiency towards the degradation of NOx in gas phase was measured in both a batch and a plug-flow reactor. The latter reactor configuration was also modeled by digital simulations.

  20. Ultrasound-assisted removal of Acid Red 17 using nanosized Fe3O4-loaded coffee waste hydrochar.

    Science.gov (United States)

    Khataee, Alireza; Kayan, Berkant; Kalderis, Dimitrios; Karimi, Atefeh; Akay, Sema; Konsolakis, Michalis

    2017-03-01

    The Fe 3 O 4 -loaded coffee waste hydrochar (Fe 3 O 4 -CHC) was synthesized using a simple precipitation method. The as-prepared adsorbent was characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) and Fourier transform infrared spectroscopy (FT-IR). The EDX analysis indicated the presence of Fe in the structure of Fe 3 O 4 -CHC. The specific surface area of hydrochar increased from 17.2 to 34.7m 2 /g after loading of Fe 3 O 4 nanoparticles onto it. The prepared Fe 3 O 4 -CHC was used for removal of Acid Red 17 (AR17) through ultrasound-assisted process. The decolorization efficiency decreased from 100 to 74% with the increase in initial dye concentration and from 100 to 91 and 85% in the presence of NaCl and Na 2 SO 4 , respectively. The synthesized Fe 3 O 4 -CHC exhibited good stability in the repeated adsorption-desorption cycles. The high correlation coefficient (R 2 =0.997) obtained from Langmuir model indicated that physical and monolayer adsorption of dye molecules occurred on the Fe 3 O 4 -CHC surface. Furthermore, the by-products generated through the degradation of AR17 was identified by gas chromatography-mass spectrometry analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Efficient hydrophobization and solvent microextraction for determination of trace nano-sized silver and titanium dioxide in natural waters.

    Science.gov (United States)

    Majedi, Seyed Mohammad; Kelly, Barry C; Lee, Hian Kee

    2013-07-30

    Hydrophobic silver and titanium (IV) oxide nanoparticles (commercial Ag and TiO2 NPs with average particle sizes of 17 and 19 nm, respectively) were quantitatively transferred into organic phase in natural water samples. Five NP surface modification and solvent extraction agents (reagents) types, mercaptocarboxylic acid, alkylamine, mediator solvent, extraction solvent, and surfactant, were investigated and optimized with three-level orthogonal array design (OAD), an OA27 (3(13)) matrix. The most favorable reagents and experimental conditions were then examined. The best extraction efficiencies of 78.6 and 73.7% were obtained for 1 mg L(-1) citrate-stabilized Ag and TiO2 NPs, respectively, with 0.5 mM of 11-mercaptoundecanoic acid, 1.5 mM of octadecylamine, 1 mL of methanol, 150 μL of cyclohexane, 0.05 mM of tetra-n-octylammonium bromide, pH=8.0, adsorption time of 2h, sonication time of 3 min, and centrifugation time of 10 min. Enrichment factors were 97 and 83, for Ag and TiO2 NPs, respectively. The optimum extraction conditions were successfully applied to genuine water samples at spiking levels of 2-100 μg L(-1) of Ag and TiO2 NPs. The relative recoveries of (69.0-85.1)% and (61.5-78.5)% were obtained for Ag and TiO2 NPs, respectively. The extracted surface-modified NPs were characterized with transmission electron microscopy, selected area electron diffraction, energy-dispersive X-ray, ultraviolet-visible, and Fourier transform infrared spectroscopic techniques. Based on the results, efficient ligand exchange and acid-base pair formation were observed on the NP surface without significant change in its original properties. The organic phase was microwave digested, and analyzed with inductively coupled plasma (ICP) optical emission spectroscopy and ICP mass spectrometry (ICP-MS). Detection limits of ICP-MS analyses of Ag and TiO2 NPs were 0.02 and 0.07 μg L(-1), respectively. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Long-range attractive forces extending from the alumina’s nanolayer surface in aqueous solutions

    Directory of Open Access Journals (Sweden)

    Leonid A. Kaledin

    2015-07-01

    Full Text Available Aluminum oxide-hydroxide nanolayer with a thickness of approximately 1.2 nm is electroadhesively deposited onto silicious support material with large surface area of about 50 m2/g, forming a highly electropositive composite of boehmite nanolayer in the form of monocrystalline oxide/hydroxide (α-Al2O3·H2O on the second electronegative solid. The composite can be viewed as a sphere with a rough surface and charge density of approximately 0.08 C/m2. This creates a significant electric field with negligible screening (ka ≪ 1 in the region close to the surface of the nanocomposite. This field attracts nano- and micron-sized particles from as far as 200 μm in a few seconds, many orders of magnitude greater than conventional Derjaguin–Landau–Verwey–Overbeek (DLVO theory, which predicts only nanometer-scale effects arising from the presence of the surface. The strong electric field on the surface is then able to retain small particles such as viruses, atomically thin sheets of graphene oxide, RNA, DNA, proteins, dyes as well as heavy metals such as cobalt, arsenic, and lead. Alumina’s nanolayer surface can be further functionalized by adding other sub-micron or nano-sized particles to target a specific contaminant. An example is shown where alumina nanolayer is coated with nano-sized iron monohydrate to yield an arsenic sorbent that shows high sorption capacity.

  3. Mechanism behind the formation of self-assembled nano-sized clusters in diamond-like carbon nanocomposite.

    Science.gov (United States)

    Foong, Yuan Mei; Koh, Angel Ting Ting; Niu, Lifang; Chua, Daniel Hock Chuan

    2011-12-01

    Many studies have shown that Diamond-like carbon (DLC) films with diversified material properties are obtainable through doping process but the presence of the dopants were reported to form independent nanoclusters within the carbon matrix. Using combined analysis from theoretical estimations (Saha's equation and coefficient of absorption, alpha(p)), Transport of Ions In Matter (TRIM) simulation and experimental results, this work examined the mechanism behind the formation of self-assembled nanoclusters in DLC nanocomposite. We showed that the presence of metal dopants increased the heat dissipation on DLC, which allowed the energetic metal species to diffuse and enhance the formation of nanoclusters that increased the surface roughness of the films. In addition, TRIM and X-ray Photoelectron Spectroscopy (XPS) hinted the presence of energetic species may force the carbon ions to react with the interface to form silicon carbide bonds, which may be a more dominant factor compared to internal stress reduction in improving the adhesion strength of DLC.

  4. Influence of Inter-Particle Interactions on the Superparamagnetic Relaxation Time in a Sample of Nano-Sized Feroxyhyte Particles

    DEFF Research Database (Denmark)

    Meaz, T; Koch, C. Bender; Mørup, Steen

    1996-01-01

    Ultrafine particles of feroxyhyte (delta-FeOOH) have been studied by Mossbauer spectroscopy. Coating of the particles with oleic acid results in a decrease of the superparamagnetic blocking temperature, whereas pressing the particles with a uniaxial pressure of 1.3 GPa leads to an increase...... of the blocking temperature. The results suggest that the interaction between the ferrimagnetic particles leads to ordering of the magnetic moments below a critical temperature, which depends on the strength of the interaction. Measurements at 5 K in a large magnetic field show that the particles have a non......-collinear spin structure. The degree of spin-canting increases with increasing strength of interactions. This suggests that the exchange interaction between surface iron atoms in neighbouring particles affects the canting....

  5. Surface plasmon enhanced interfacial electron transfer and resonance Raman, surface-enhanced resonance Raman studies of cytochrome C mutants

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Junwei [Iowa State Univ., Ames, IA (United States)

    1999-11-08

    Surface plasmon resonance was utilized to enhance the electron transfer at silver/solution interfaces. Photoelectrochemical reductions of nitrite, nitrate, and CO2 were studied on electrochemically roughened silver electrode surfaces. The dependence of the photocurrent on photon energy, applied potential and concentration of nitrite demonstrates that the photoelectrochemical reduction proceeds via photoemission process followed by the capture of hydrated electrons. The excitation of plasmon resonances in nanosized metal structures resulted in the enhancement of the photoemission process. In the case of photoelectrocatalytic reduction of CO2, large photoelectrocatalytic effect for the reduction of CO2 was observed in the presence of surface adsorbed methylviologen, which functions as a mediator for the photoexcited electron transfer from silver metal to CO2 in solution. Photoinduced reduction of microperoxidase-11 adsorbed on roughened silver electrode was also observed and attributed to the direct photoejection of free electrons of silver metal. Surface plasmon assisted electron transfer at nanostructured silver particle surfaces was further determined by EPR method.

  6. Hemocompatible surface of electrospun nanofibrous scaffolds by ATRP modification

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Wenjie [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Feng, Yakai, E-mail: yakaifeng@hotmail.com [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Key Laboratory of Systems Bioengineering of Ministry of Education, Tianjin University, Tianjin 300072 (China); Tianjin University-Helmholtz-Zentrum Geesthacht, Joint Laboratory for Biomaterials and Regenerative Medicine, Weijin Road 92, 300072 Tianjin (China); Wang, Heyun [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832002 (China); Yang, Dazhi [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); An, Bo [Department of Orthopedics, Affiliated Hospital of Logistics University of Chinese People' s Armed Police Force, Tianjin 300162 (China); Zhang, Wencheng [Department of Physiology and Pathophysiology, Logistics University of Chinese People' s Armed Police Force, Tianjin 300162 (China); Khan, Musammir [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Guo, Jintang [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Tianjin University-Helmholtz-Zentrum Geesthacht, Joint Laboratory for Biomaterials and Regenerative Medicine, Weijin Road 92, 300072 Tianjin (China)

    2013-10-15

    The electrospun scaffolds are potential application in vascular tissue engineering since they can mimic the nano-sized dimension of natural extracellular matrix (ECM). We prepared a fibrous scaffold from polycarbonateurethane (PCU) by electrospinning technology. In order to improve the hydrophilicity and hemocompatibility of the fibrous scaffold, poly(ethylene glycol) methacrylate (PEGMA) was grafted onto the fiber surface by surface-initiated atom transfer radical polymerization (SI-ATRP) method. Although SI-ATRP has been developed and used for surface modification for many years, there are only few studies about the modification of electrospun fiber by this method. The modified fibrous scaffolds were characterized by SEM, Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS). The scaffold morphology showed no significant difference when PEGMA was grafted onto the scaffold surface. Based on the water contact angle measurement, the surface hydrophilicity of the scaffold surface was improved significantly after grafting hydrophilic PEGMA (P = 0.0012). The modified surface showed effective resistance for platelet adhesion compared with the unmodified surface. Activated partial thromboplastin time (APTT) of the PCU-g-PEGMA scaffold was much longer than that of the unmodified PCU scaffold. The cyto-compatibility of electrospun nanofibrous scaffolds was tested by human umbilical vein endothelial cells (HUVECs). The images of 7-day cultured cells on the scaffold surface were observed by SEM. The modified scaffolds showed high tendency to induce cell adhesion. Moreover, the cells reached out pseudopodia along the fibrous direction and formed a continuous monolayer. Hemolysis test showed that the grafted chains of PEGMA reduced blood coagulation. These results indicated that the modified electrospun nanofibrous scaffolds were potential application as artificial blood vessels. Highlights: • Electrospun nanofibrous scaffolds were successfully

  7. Preparation, characterization and in vitro cytotoxicity of BSA-based nanospheres containing nanosized magnetic particles and/or photosensitizer

    International Nuclear Information System (INIS)

    Rodrigues, Marcilene M.A.; Simioni, Andreza R.; Primo, Fernando L.; Siqueira-Moura, Marigilson P.; Morais, Paulo C.; Tedesco, Antonio C.

    2009-01-01

    This study reports on the preparation, characterization and in vitro toxicity test of a new nano-drug delivery system (NDDS) based on bovine serum albumin (BSA) nanospheres which incorporates surface-functionalized magnetic nanoparticles (MNP) and/or the silicon(IV) phthalocyanine (NzPc). The new NDDS was engineered for use in photodynamic therapy (PDT) combined with hyperthermia (HPT) to address cancer treatment. The BSA-based nanospheres, hosting NzPc, MNP or both (NzPc and MNP), present spherical shape with hydrodynamic average diameter values ranging from 170 to 450 nm and zeta potential of around -23 mV. No difference on the fluorescence spectrum of the encapsulated NzPc was found regardless of the presence of MNP. Time-dependent fluorescence measurements of the encapsulated NzPc revealed a bi-exponential decay for samples incorporating only NzPc and NzPc plus MNP, in the time window ranging from 1.70 to 5.20 ns. The in vitro assay, using human fibroblasts, revealed no cytotoxic effect in all samples investigated, demonstrating the potential of the tested system as a synergistic NDDS.

  8. Advancements in artificial heart valve disks using nano-sized thin films deposited by CVD and sol-gel techniques

    International Nuclear Information System (INIS)

    Kousar, Y.; Ali, N.; Neto, V.F.; Mei, S.; Gracio, J.

    2003-01-01

    Pyrolytic carbon (PyC) is widely used in manufacturing commercial artificial heart valve disks (HVD). Although, PyC is commonly used in HVD, it is not the best material for this application since its blood compatibility is not ideal for prolonged clinical use. As a result thrombosis often occurs and the patients are required to take anti- coagulation drugs on a regular basis in order to minimise the formation of thrombosis. However, the anti-coagulation therapy gives rise to some detrimental side effects in patients. Therefore, it is extremely urgent that newer and more technically advanced materials with better surface and bulk properties are developed. In this paper, we report the mechanical properties of PyC-HVD, namely, strength, wear resistance and coefficient of friction. The strength of the material was assessed using Brinell indentation tests. Furthermore, wear resistance and the coefficient of friction values were obtained from the pin-on-disk testing. The micro-structural properties of PyC were characterized using XRD, Raman spectroscopy and SEM analysis. Also, in this paper we report the preparation of free standing nanocrystalline diamond films (FSND) using the time-modulated chemical vapor deposition (TMCVD) process. Furthermore, the sol-gel technique was used to uniformly coat PyC-HVD with dense, nanocrystalline-titanium oxide (nc-TiO/sub 2/) coatings. The as-grown nc-TiO/sub 2/ coatings were characterized for microstructure using SEM and XRD analysis. (author)

  9. Molecular dynamics study of the nanosized droplet spreading: The effect of the contact line forces on the kinetic energy dissipation

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Hong Min [Department of Mechanical Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Kondaraju, Sasidhar [Department of Mechanical Science, Indian Institute of Technology Bhubaneswar, Bhubaneswar, Odisha 751013 (India); Lee, Jung Shin [Department of Mechanical Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Suh, Youngho; Lee, Joonho H. [Samsung Electronics, Mechatronics R& D Center, Hwaseong-si, Gyeonggi-do 445-330 (Korea, Republic of); Lee, Joon Sang, E-mail: joonlee@yonsei.ac.kr [Department of Mechanical Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of)

    2017-07-01

    Highlights: • Contact line forces, including friction and spreading forces are directly calculated. • Overall trends of variations in contact line forces during droplet spreading process show characteristics of contact line forces. • Detail relations of contact line forces and atomic kinetics in the contact line provide a clear evidence of the possible energy dissipation mechanism in droplet spreading process. - Abstract: Recent studies have revealed that contact line forces play an important role in the droplet spreading process. Despite their significance, the physics related to them has been studied only indirectly and the effect of contact line forces is still being disputed. We performed a molecular dynamics simulation and mimicked the droplet spreading process at the nanoscale. Based on the results of the simulation, the contact line forces were directly calculated. We found that the forces acting on the bulk and the contact line region showed different trends. Distinct positive and negative forces, contact line spreading, and friction forces were observed near the contact line. We also observed a strong dependency of the atomic kinetics in the contact line region on the variations in the contact line forces. The atoms of the liquid in the contact line region lost their kinetic energy due to the contact line friction force and became partially immobile on the solid surface. The results of the current study will be useful for understanding the role of the contact line forces on the kinetic energy dissipation in the contact line region.

  10. Study of nanosized copper-doped ZnO dilute magnetic semiconductor thick films for spintronic device applications

    Science.gov (United States)

    Zargar, Rayees Ahmad; Arora, Manju; Bhat, Riyaz Ahmed

    2018-01-01

    Screen-printed pure and copper-doped ZnO dilute magnetic semiconductor thick films were casted from chemically co-precipitated zinc oxide and copper-doped zinc oxide nanoparticles followed by sintering at 550 °C to obtain desired stoichiometry in spintronic device applications. These thick films were characterized by different analytical techniques to reveal their structure, surface morphology, optical, magnetic and electrical characteristics. The diffraction peaks pertaining to wurtzite structure are observed in XRD patterns of these films, while SEM images show smooth and dense morphology. Infrared transmission and Raman spectra exhibit vibrational bands pertaining to Zn-O-stretching modes and E 2 (high) phonon mode, respectively, in 4000-400 cm-1 region. The direct bandgap energy of these films derived from diffused reflectance spectroscopy varies in 3.21-3.13 eV range and is supported by PL spectroscopy study. The semiconducting behaviour and activation energy of these thick films has been confirmed by DC conductivity measurements. Electron paramagnetic resonance spectra showed derivative signal of g value 2.0018 in pure ZnO due to oxygen vacancies produced during synthesis and 2.0704 in copper-doped ZnO dilute magnetic semiconductor films.

  11. Superhydrophobic surfaces

    Science.gov (United States)

    Wang, Evelyn N; McCarthy, Matthew; Enright, Ryan; Culver, James N; Gerasopoulos, Konstantinos; Ghodssi, Reza

    2015-03-24

    Surfaces having a hierarchical structure--having features of both microscale and nanoscale dimensions--can exhibit superhydrophobic properties and advantageous condensation and heat transfer properties. The hierarchical surfaces can be fabricated using biological nanostructures, such as viruses as a self-assembled nanoscale template.

  12. Spherical Surfaces

    DEFF Research Database (Denmark)

    Brander, David

    2016-01-01

    We study surfaces of constant positive Gauss curvature in Euclidean 3-space via the harmonicity of the Gauss map. Using the loop group representation, we solve the regular and the singular geometric Cauchy problems for these surfaces, and use these solutions to compute several new examples. We give...

  13. Synthesis and characterization of nanosized calcium phosphates by flame spray pyrolysis, and their effect on osteogenic differentiation of stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Ataol, Sibel; Tezcaner, Ayşen [Middle East Technical University, Department of Biomedical Engineering (Turkey); Duygulu, Ozgur [TUBITAK Marmara Research Center, Materials Institute (Turkey); Keskin, Dilek [Middle East Technical University, Department of Biomedical Engineering (Turkey); Machin, Nesrin E., E-mail: nesrinmachin@gmail.com [Kocaeli University, Department of Chemical Engineering (Turkey)

    2015-02-15

    The present study evaluates the synthesis of biocompatible osteoconductive and osteoinductive nano calcium phosphate (CaP) particles by industrially applied, aerosol-derived flame spray pyrolysis method for biomedical field. Calcium phosphate nanoparticles were produced in a range of calcium-to-phosphorus ratio, (1.20–2.19) in order to analyze the morphology and crystallinity changes, and to test the bioactivity of particles. The characterization results confirmed that nanometer-sized, spherical calcium phosphate particles were produced. The average primary particle size was determined as 23 nm by counting more than 500 particles in TEM pictures. XRD patterns, HRTEM, SAED, and SEM analyses revealed the amorphous nature of the as-prepared nano calcium phosphate particles at low Ca/P ratios. Increases in the specific surface area and crystallinity were observed with the increasing Ca/P ratio. TGA–DTA analysis showed that the thermally stable crystal phases formed after 700 °C. Cell culture studies were conducted with urine-derived stem cells that possess the characteristics of mesenchymal stem cells. Synthesized amorphous nanoparticles did not have cytotoxic effect at 5–50 μg/ml concentration range. Cells treated with the as-prepared nanoparticles had higher alkaline phosphatase (ALP) enzyme activity than control cells, indicating osteogenic differentiation of cells. A slight decrease in ALP activity of cells treated with two highest Ca:P ratios at 50 μg/ml concentration was observed at day 7. The findings suggest that calcium phosphate nanoparticles produced in this work have a potential to be used as biomaterials in biomedical applications.

  14. Synthesis and characterization of nanosized calcium phosphates by flame spray pyrolysis, and their effect on osteogenic differentiation of stem cells

    Science.gov (United States)

    Ataol, Sibel; Tezcaner, Ayşen; Duygulu, Ozgur; Keskin, Dilek; Machin, Nesrin E.

    2015-02-01

    The present study evaluates the synthesis of biocompatible osteoconductive and osteoinductive nano calcium phosphate (CaP) particles by industrially applied, aerosol-derived flame spray pyrolysis method for biomedical field. Calcium phosphate nanoparticles were produced in a range of calcium-to-phosphorus ratio, (1.20-2.19) in order to analyze the morphology and crystallinity changes, and to test the bioactivity of particles. The characterization results confirmed that nanometer-sized, spherical calcium phosphate particles were produced. The average primary particle size was determined as 23 nm by counting more than 500 particles in TEM pictures. XRD patterns, HRTEM, SAED, and SEM analyses revealed the amorphous nature of the as-prepared nano calcium phosphate particles at low Ca/P ratios. Increases in the specific surface area and crystallinity were observed with the increasing Ca/P ratio. TGA-DTA analysis showed that the thermally stable crystal phases formed after 700 °C. Cell culture studies were conducted with urine-derived stem cells that possess the characteristics of mesenchymal stem cells. Synthesized amorphous nanoparticles did not have cytotoxic effect at 5-50 μg/ml concentration range. Cells treated with the as-prepared nanoparticles had higher alkaline phosphatase (ALP) enzyme activity than control cells, indicating osteogenic differentiation of cells. A slight decrease in ALP activity of cells treated with two highest Ca:P ratios at 50 μg/ml concentration was observed at day 7. The findings suggest that calcium phosphate nanoparticles produced in this work have a potential to be used as biomaterials in biomedical applications.

  15. Novel nano-sized MR contrast agent mediates strong tumor contrast enhancement in an oncogene-driven breast cancer model.

    Directory of Open Access Journals (Sweden)

    Per-Olof Eriksson

    Full Text Available The current study was carried out to test the potential of a new nanomaterial (Spago Pix as a macromolecular magnetic MR contrast agent for tumor detection and to verify the presence of nanomaterial in tumor tissue. Spago Pix, synthesized by Spago Nanomedical AB, is a nanomaterial with a globular shape, an average hydrodynamic diameter of 5 nm, and a relaxivity (r1 of approximately 30 (mM Mn-1 s-1 (60 MHz. The material consists of an organophosphosilane hydrogel with strongly chelated manganese (II ions and a covalently attached PEG surface layer. In vivo MRI of the MMTV-PyMT breast cancer model was performed on a 3 T clinical scanner. Tissues were thereafter analyzed for manganese and silicon content using inductively coupled plasma-atomic emission spectroscopy (ICP-AES. The presence of nanomaterial in tumor and muscle tissue was assessed using an anti-PEG monoclonal antibody. MR imaging of tumor-bearing mice (n = 7 showed a contrast enhancement factor of 1.8 (tumor versus muscle at 30 minutes post-administration. Contrast was retained and further increased 2-4 hours after administration. ICP-AES and immunohistochemistry confirmed selective accumulation of nanomaterial in tumor tissue. A blood pharmacokinetics analysis showed that the concentration of Spago Pix gradually decreased over the first hour, which was in good agreement with the time frame in which the accumulation in tumor occurred. In summary, we demonstrate that Spago Pix selectively enhances MR tumor contrast in a clinically relevant animal model. Based on the generally higher vascular leakiness in malignant compared to benign tissue lesions, Spago Pix has the potential to significantly improve cancer diagnosis and characterization by MRI.

  16. Development of a novel nano-sized anti-VEGFA nanobody with enhanced physicochemical and pharmacokinetic properties.

    Science.gov (United States)

    Khodabakhsh, Farnaz; Norouzian, Dariush; Vaziri, Behrouz; Ahangari Cohan, Reza; Sardari, Soroush; Mahboudi, Fereidoun; Behdani, Mahdi; Mansouri, Kamran; Mehdizadeh, Ardavan

    2017-08-25

    Since physiological and pathological processes occur at nano-environments, nanotechnology has considered as an efficient tool for designing of next generation specific biomolecules with enhanced pharmacodynamic and pharmacodynamic properties. In the current investigation, by control of the size and hydrodynamic volume at the nanoscale, for the first time, physicochemical and pharmacokinetic properties of an anti-VEGFA nanobody was remarkably improved by attachment of a Proline-Alanine-Serine (PAS) rich sequence. The results elucidated unexpected impressive effects of PAS sequence on physicochemical properties especially on size, hydrodynamics radius, and even solubility of nanobody. CD analysis revealed an increment in random coil structure of the PASylated protein in comparison to native one without any change in charge state or binding kinetic parameters of nanobody assessed by isoelectric focusing and surface plasmon resonance measurements, respectively. In vitro biological activities of nanobody were not affected by coupling of the PAS sequence. In contrast, the terminal half-life was significantly increased by a factor of 14 for the nanobody-PAS after single dose IV injection to the mice. Our study demonstrated that the control of size in the design of small therapeutic proteins has a promising effect on the stability and solubility, in addition to their physiochemical and pharmacokinetic properties. The designed new anti-VEGFA nanobody could promise a better therapeutic agent with a long administration intervals and lower dose, which in turn leads to a better patient compliance. Size adjustment of an anti-VEGF nanobody at the nanoscale by the attachment of a natural PAS polymer remarkably improves physicochemical properties, as well as a pharmacokinetic profile without any change in biological activity of the miniaturized antibody.

  17. Analysis of nanoparticle–protein coronas formed in vitro between nanosized welding particles and nasal lavage proteins

    Science.gov (United States)

    Ali, Neserin; Mattsson, Karin; Rissler, Jenny; Karlsson, Helen Marg; Svensson, Christian R.; Gudmundsson, Anders; Lindh, Christian H.; Jönsson, Bo A. G.; Cedervall, Tommy; Kåredal, Monica

    2016-01-01

    Abstract Welding fumes include agglomerated particles built up of primary nanoparticles. Particles inhaled through the nose will to some extent be deposited in the protein-rich nasal mucosa, and a protein corona will be formed around the particles. The aim was to identify the protein corona formed between nasal lavage proteins and four types of particles with different parameters. Two of the particles were formed and collected during welding and two were manufactured iron oxides. When nasal lavage proteins were added to the particles, differences were observed in the sizes of the aggregates that were formed. Measurements showed that the amount of protein bound to particles correlated with the relative size increase of the aggregates, suggesting that the surface area was associated with the binding capacity. However, differences in aggregate sizes were detected when nasal proteins were added to UFWF and Fe2O3 particles (having similar agglomerated size) suggesting that yet parameters other than size determine the binding. Relative quantitative mass spectrometric and gel-based analyses showed differences in the protein content of the coronas. High-affinity proteins were further assessed for network interactions. Additional experiments showed that the inhibitory function of secretory leukocyte peptidase inhibitor, a highly abundant nasal protein, was influenced by particle binding suggesting that an understanding of protein function following particle binding is necessary to properly evaluate pathophysiological events. Our results underscore the importance of including particles collected from real working environments when studying the toxic effects of particles because these effects might be mediated by the protein corona. PMID:26186033

  18. Analysis of nanoparticle-protein coronas formed in vitro between nanosized welding particles and nasal lavage proteins.

    Science.gov (United States)

    Ali, Neserin; Mattsson, Karin; Rissler, Jenny; Karlsson, Helen Marg; Svensson, Christian R; Gudmundsson, Anders; Lindh, Christian H; Jönsson, Bo A G; Cedervall, Tommy; Kåredal, Monica

    2016-01-01

    Welding fumes include agglomerated particles built up of primary nanoparticles. Particles inhaled through the nose will to some extent be deposited in the protein-rich nasal mucosa, and a protein corona will be formed around the particles. The aim was to identify the protein corona formed between nasal lavage proteins and four types of particles with different parameters. Two of the particles were formed and collected during welding and two were manufactured iron oxides. When nasal lavage proteins were added to the particles, differences were observed in the sizes of the aggregates that were formed. Measurements showed that the amount of protein bound to particles correlated with the relative size increase of the aggregates, suggesting that the surface area was associated with the binding capacity. However, differences in aggregate sizes were detected when nasal proteins were added to UFWF and Fe2O3 particles (having similar agglomerated size) suggesting that yet parameters other than size determine the binding. Relative quantitative mass spectrometric and gel-based analyses showed differences in the protein content of the coronas. High-affinity proteins were further assessed for network interactions. Additional experiments showed that the inhibitory function of secretory leukocyte peptidase inhibitor, a highly abundant nasal protein, was influenced by particle binding suggesting that an understanding of protein function following particle binding is necessary to properly evaluate pathophysiological events. Our results underscore the importance of including particles collected from real working environments when studying the toxic effects of particles because these effects might be mediated by the protein corona.

  19. The role of stable interface in nano-sized FeNbO4 as anode electrode for lithium-ion batteries

    International Nuclear Information System (INIS)

    Wang, Ting; Shi, Shaojun; Kong, Fanjun; Yang, Gang; Qian, Bin; Yin, Fan

    2016-01-01

    Graphical abstract: After dozens of charge/discharge cycles, the electrode of Nano-FNO remains the homogeneous combination with active material and conductive carbon, but the microcrystals in Micro-FNO electrode are cracked to small particles. The pulverization of Micro-FNO not only blocks the transfer of Li + and electrons due to the separation of the active material and conductive carbon, but also results in the falling of active material from the current collector. Nano-FNO can remain the excellent capacity after dozens of cycles. - Abstract: Nano-sized FeNbO 4 (Nano-FNO) with an average diameter of 120 nm is facilely prepared by co-precipitation method. Bulk FeNbO 4 (Micro-FNO) as a comparison synthesized by conventional solid-state synthesis has an average grain size of 3–10 μm. In the high-resolution transmission electron microscopy (HRTEM) images, Nano-FNO reveals an ordered single crystal structure, but Mirco-FNO is composed of disordered crystallites with different crystal orientation. Nano-FNO as anode material delivers the initial capacity of 475 mAh g −1 which is much higher than Micro-FNO electrode of 250 mAh g −1 .After dozens of charge/discharge cycles, the electrode of Nano-FNO remains the homogeneous combination with active material and conductive carbon, but the microcrystals in Micro-FNO electrode are cracked to small particles. The pulverization of Micro-FNO not only blocks the transfer of Li + and electrons due to the separation between the active material and conductive carbon, but also results in the falling of active material from the current collector. Compared with the weakened electrochemical performances of Micro-FNO, Nano-FNO remains the excellent capacity after dozens of cycles. The charge transfer resistances of Nano-FNO and Micro-FNO after several cycles are further studied by fitting their electrochemical impedance spectra.

  20. Nano-sized iron particles may induce multiple pathways of cell death following generation of mistranscripted RNA in human corneal epithelial cells.

    Science.gov (United States)

    Park, Eun-Jung; Chae, Jae-Byoung; Kang, Seuyoung; Lyu, Jungmook; Jeong, Uiseok; Yeom, Changjoo; Kim, Younghun; Chang, Jaerak

    2017-08-01

    Iron is closely associated with an ambient particulate matters-induced inflammatory response, and the cornea that covers the front of the eye, is among tissues exposed directly to ambient particulate matters. Prior to this study, we confirmed that nano-sized iron particles (FeNPs) can penetrate the cornea. Thus, we identified the toxic mechanism of FeNPs using human corneal epithelial cells. At 24h after exposure, FeNPs located inside autophagosome-like vacuoles or freely within human corneal epithelial cells. Level of inflammatory mediators including nitric oxide, cytokines, and a chemokine was notably elevated accompanied by the increased generation of reactive oxygen species. Additionally, cell proliferation dose-dependently decreased, and level of multiple pathways of cell death-related indicators was clearly altered following exposure to FeNPs. Furthermore, expression of gene encoding DNA binding protein inhibitor (1, 2, and 3), which are correlated to inhibition of the binding of mistranscripted RNA, was significantly down-regulated. More importantly, expression of p-Akt and caspase-3 and conversion to LC3B-II from LC3B-I was enhanced by pretreatment with a caspase-1 inhibitor. Taken together, we suggest that FeNPs may induce multiple pathways of cell death via generation of mistranscripted RNA, and these cell death pathways may influence by cross-talk. Furthermore, we propose the need of further study for the possibility of tumorigenesis following exposure to FeNPs. Copyright © 2017 Elsevier Ltd. All rights reserved.