Synthesis and magnetic properties of single-crystalline BaFe12O19 nanoparticles

International Nuclear Information System (INIS)

Yu Jiangying; Tang Shaolong; Zhai Lin; Shi Yangguang; Du Youwei

2009-01-01

Rod-like and platelet-like nanoparticles of simple-crystalline barium hexaferrite (BaFe 12 O 19 ) have been synthesized by the molten salt method. Both particle size and morphology change with the reaction temperature and time. The easy magnetization direction (0 0 l) of the BaFe 12 O 19 nanoparticles has been observed directly by performing X-ray diffraction on powders aligned at 0.5 T magnetic field. The magnetic properties of the BaFe 12 O 19 magnet were investigated with various sintering temperatures. The maximum values of saturation magnetization (σ s =65.8 emu/g), remanent magnetization (σ r =56 emu/g) and coercivity field (H ic =5251 Oe) of the aligned samples occurred at the sintering temperatures of 1100 deg. C. These results indicate that BaFe 12 O 19 nanoparticles synthesized by the molten salt method should enable detailed investigation of the size-dependent evolution of magnetism, microwave absorption, and realization of a nanodevice of magnetic media.

Magnetic properties of crystalline nanoparticles with different sizes and shapes

Energy Technology Data Exchange (ETDEWEB)

Lima, Ana T.A. [Departamento de Física, Universidade Federal do Ceará, Caixa Postal 6030, Campus do Pici, 60455-760 Fortaleza, Ceará (Brazil); Universidade Federal Rural do Semi-Árido, Campus de Caraubas, RN 333, Rio Grande do Norte (Brazil); Dantas, Ana L.; Almeida, N.S. [Departamento de Física, Universidade do Estado do Rio Grande do Norte, 59610-210 Mossoró, Rio Grande do Norte (Brazil)

2017-03-01

The effects of shape and finite size on the physical behavior of nanostructured antiferromagnetic particles are investigated. They were modeled as ellipsoidal systems which preserve the crystalline structure of the correspondent bulk material. In our analysis we consider nanoparticles composed by magnetic ions which are themselves insensitive to the presence of surfaces and/or interfaces. Results are shown for structures similar to MnF{sub 2} and NiO crystals. Special attention is given to these last once their singular magnetic arrangement, as well as, their use at different technological and/or biomedical applications, has motivated intense experimental studies at different laboratories. We use the parameters that describe the correspondent bulk material to discuss the magnetic behavior of these particles for different volumes and shapes. - Highlights: • The number of magnetic phases of tetragonal AFM nanoparticles depends on their shape. • Hysteresis loops of NiO particles depends on the direction of the dc magnetic field. • The high frequencies normal modes of NiO particles are insensitive to their geometry.

Hydrothermal synthesis of histidine-functionalized single-crystalline gold nanoparticles and their pH-dependent UV absorption characteristic.

Science.gov (United States)

Liu, Zhiguo; Zu, Yuangang; Fu, Yujie; Meng, Ronghua; Guo, Songling; Xing, Zhimin; Tan, Shengnan

2010-03-01

L-Histidine capped single-crystalline gold nanoparticles have been synthesized by a hydrothermal process under a basic condition at temperature between 65 and 150 degrees C. The produced gold nanoparticles were spherical with average diameter of 11.5+/-2.9nm. The synthesized gold colloidal solution was very stable and can be stored at room temperature for more than 6 months. The color of the colloidal solution can change from wine red to mauve, purple and blue during the acidifying process. This color changing phenomenon is attributed to the aggregation of gold nanoparticles resulted from hydrogen bond formation between the histidines adsorbed on the gold nanoparticles surfaces. This hydrothermal synthetic method is expected to be used for synthesizing some other amino acid functionalized gold nanomaterials.

Cubic liquid crystalline nanoparticles containing a polysaccharide from Ulva fasciata with potent antihyperlipidaemic activity

Directory of Open Access Journals (Sweden)

Azza A. Matloub

2018-02-01

Full Text Available The present study involves the preparation of cubic liquid crystalline nanoparticles (cubsomes for liver targeting to assess the potential of a formulated bioactive polysaccharide isolated from the hot aqueous extract of Ulva fasciata as an alternative natural agent with anti-hyperlipidaemic activity. Cubosomal nanoparticles were prepared by disrupting the cubic gel phase of the polysaccharide and water in the presence of a surfactant. Different lipid matrices and stabilizers were tested. All the formulations were in the nanosize range and showed sufficient negative charge to inhibit the aggregation of the cubosomes. Drug entrapment efficiencies (EEs% were determined and in vitro release studies were performed. Transmission electron microscopy (TEM and differential scanning calorimetry were used to analyze the loaded cubosomal nanoparticles containing glyceryl monostearate (GMO 2.25 g, poloxamer 407 (0.25 g and 50 mg of the polysaccharide. A preclinical study comparing the cubic liquid crystalline nanoparticles containing polysaccharide to fluvastatin as a reference drug in hyperlipidaemic rats was conducted. The rats treated with the polysaccharide- loaded cubosomes showed significant decreases in total cholesterol (TC, triglycerides (TG and total lipid (TL compared to the untreated HL rats. In addition, oxidative stress and antioxidant biomarkers were measured in the HL rats. Compared to the untreated HL rats, the cubosome treated rats showed a significant reduction in malondialdehyde (MDA, whereas insignificant changes were detected in nitric oxide (NO, glutathione (GSH levels and total antioxidant capacity (TAC. Further, vascular and intercellular adhesion molecules (VCAM, ICAM, and myeloperoxidase were demonstrated. A histopathological examination was conducted to study the alterations in histopathological lesions and to document the biochemical results. In conclusion, this study demonstrates the superiority of using a natural lipid

Effects of γ-irradiation and thermal treatment of crystallinity of drawn HDPE

International Nuclear Information System (INIS)

Liu Zhanjun; Silverman, J.

1997-01-01

The effect of absorbed dose irradiated in vacuum and air on the crystallinity of drawn HDPE was studied. Experimental results show that up to 250 kGy of absorbed dose when irradiated in vacuum, the crystallinity of drawn HDPE is decreased from about 75% to about 71%, and then the increase of absorbed dose until 1000 kGy has no further effect in lowering the crystallinity; when irradiated in air, an absorbed dose of 1000 kGy has no effect on the crystallinity of drawn HDPE. The effect of temperature of thermal treatment on the crystallinity of unirradiated drawn HDPE was also investigated. At first, the crystallinity is increased with the increase of temperature of thermal treatment, at about 120 degree C, it reaches the maximum value, and then it is rapidly lowered with the further increase of temperature of thermal treatment. Based on the existence of a lot of voids and lattice defects inside the drawn HDPE, the above experimental results were explained

Hydrothermal synthesis of highly crystalline RuS2 nanoparticles as cathodic catalysts in the methanol fuel cell and hydrochloric acid electrolysis

International Nuclear Information System (INIS)

Li, Yanjuan; Li, Nan; Yanagisawa, Kazumichi; Li, Xiaotian; Yan, Xiao

2015-01-01

Highlights: • Highly crystalline RuS 2 nanoparticles have been first synthesized by a “one-step” hydrothermal method. • The product presents a pure cubic phase of stoichiometric ratio RuS 2 with average particle size of 14.8 nm. • RuS 2 nanoparticles were used as cathodic catalysts in methanol fuel cell and hydrochloric acid electrolysis. • The catalyst outperforms commercial Pt/C in methanol tolerance and stability towards Cl − . - Abstract: Highly crystalline ruthenium sulfide (RuS 2 ) nanoparticles have been first synthesized by a “one-step” hydrothermal method at 400 °C, using ruthenium chloride and thiourea as reactants. The products were characterized by powder X-ray diffraction (XRD), scanning electron microscopy/energy disperse spectroscopy (SEM/EDS), thermo gravimetric-differential thermal analyze (TG-DTA), transmission electron microscopy equipped with selected area electron diffraction (TEM/SAED). Fourier transform infrared spectra (IR), and X-ray photoelectron spectroscopy (XPS). XRD result illustrates that the highly crystalline product presents a pure cubic phase of stoichiometric ratio RuS 2 and the average particle size is 14.8 nm. SEM and TEM images display the products have irregular shape of 6–25 nm. XPS analyst indicates that the sulfur exists in the form of S 2 2− . Cyclic voltammetry (CV), rotating disk electrode (RDE), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) measurements are conducted to evaluate the electrocatalytic activity and stability of the highly crystalline RuS 2 nanoparticles in oxygen reduction reaction (ORR) for methanol fuel cell and hydrochloric acid electrolysis. The results illustrate that RuS 2 is active towards oxygen reduction reaction. Although the activity of RuS 2 is lower than that of Pt/C, the RuS 2 catalyst outperforms commercial Pt/C in methanol tolerance and stability towards Cl −

Atomic-scale microstructural characterization and dielectric properties of crystalline cubic pyrochlore Bi1.5MgNb1.5O7 nanoparticles synthesized by sol-gel method

KAUST Repository

Zhang, Yuan; Zhu, Xinhua; Zhou, Shunhua; Zhu, Jianmin; Liu, Zhiguo; Al-Kassab, Talaat

2013-01-01

Here, we report the atomic-scale microstructural characterization and dielectric properties of crystalline cubic pyrochlore Bi1.5MgNb 1.5O7 (BMN) nanoparticles with mean size of 70 nm, which were synthesized by sol-gel method. The crystallinity, phase formation, morphology, and surface microstructure of the BMN nanoparticles were characterized by X-ray diffraction (XRD), Raman spectra, transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM), respectively. The phase evolution of the BMN nanoparticles investigated by XRD patterns showed that uniform cubic pyrochlore BMN nanoparticles were obtained after calcination at temperature of 800 C, and their structural information was revealed by Raman spectrum. TEM images demonstrated that the BMN nanoparticles had a spherical morphology with an average particle size of 70 nm, and their crystalline nature was revealed by HRTEM images. In addition, HRTEM images also demonstrate a terrace-ledge-kink (TLK) surface structure at the edges of rough BMN nanoparticles, where the terrace was on the (100) plane, and the ledge on the (001) plane. The formation of such a TLK surface structure can be well explained by a theory of periodic bond chains. Due to the surface structural reconstruction in the BMN nanoparticles, the formation of a tetragonal structure in a rough BMN nanoparticle was also revealed by HRTEM image. The BMN nanoparticles exhibited dielectric constants of 50 at 100 kHz and 30 at 1 MHz, and the dielectric loss of 0.19 at 1 MHz. © 2013 Springer Science+Business Media Dordrecht.

Atomic-scale microstructural characterization and dielectric properties of crystalline cubic pyrochlore Bi1.5MgNb1.5O7 nanoparticles synthesized by sol-gel method

KAUST Repository

Zhang, Yuan

2013-12-24

Here, we report the atomic-scale microstructural characterization and dielectric properties of crystalline cubic pyrochlore Bi1.5MgNb 1.5O7 (BMN) nanoparticles with mean size of 70 nm, which were synthesized by sol-gel method. The crystallinity, phase formation, morphology, and surface microstructure of the BMN nanoparticles were characterized by X-ray diffraction (XRD), Raman spectra, transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM), respectively. The phase evolution of the BMN nanoparticles investigated by XRD patterns showed that uniform cubic pyrochlore BMN nanoparticles were obtained after calcination at temperature of 800 C, and their structural information was revealed by Raman spectrum. TEM images demonstrated that the BMN nanoparticles had a spherical morphology with an average particle size of 70 nm, and their crystalline nature was revealed by HRTEM images. In addition, HRTEM images also demonstrate a terrace-ledge-kink (TLK) surface structure at the edges of rough BMN nanoparticles, where the terrace was on the (100) plane, and the ledge on the (001) plane. The formation of such a TLK surface structure can be well explained by a theory of periodic bond chains. Due to the surface structural reconstruction in the BMN nanoparticles, the formation of a tetragonal structure in a rough BMN nanoparticle was also revealed by HRTEM image. The BMN nanoparticles exhibited dielectric constants of 50 at 100 kHz and 30 at 1 MHz, and the dielectric loss of 0.19 at 1 MHz. © 2013 Springer Science+Business Media Dordrecht.

Facile synthesis of both needle-like and spherical hydroxyapatite nanoparticles: Effect of synthetic temperature and calcination on morphology, crystallite size and crystallinity

International Nuclear Information System (INIS)

Wijesinghe, W.P.S.L.; Mantilaka, M.M.M.G.P.G.; Premalal, E.V.A.; Herath, H.M.T.U.; Mahalingam, S.; Edirisinghe, M.; Rajapakse, R.P.V.J.; Rajapakse, R.M.G.

2014-01-01

Synthetic hydroxyapatite (HA) nanoparticles, that mimic natural HA, are widely used as biocompatible coatings on prostheses to repair and substitute human bones. In this study, HA nanoparticles are prepared by precipitating them from a precursor solution containing calcium sucrate and ammonium dihydrogen orthophosphate, at a Ca/P mole ratio of 1.67:1, at temperatures, ranging from 10 °C to 95 °C. A set of products, prepared at different temperatures, is analyzed for their crystallinity, crystallite size, morphology, thermal stability and composition, by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and Fourier transform infrared (FT-IR) spectroscopic techniques, while the other set is analyzed after calcining the respective products, soon after their synthesis, for 3 h, at 700 °C. The as-prepared products, after 2 h of drying, without any calcination, are not crystalline, but they grow very slowly into needle-like morphologies, as they are ripened with time. The percentage crystallinity of the final products increases from 15% to 52%, with increasing the preparative temperature. The calcined samples always produce spherical nanoparticles of essentially the same diameter, between 90 nm and 100 nm, which does not change due to aging and preparative temperatures. Therefore, the same method can be utilized to synthesize both spherical and needle-like nanoparticles of hydroxyapatite, with well-defined sizes and shapes. The ability to use readily available cheap raw materials, for the synthesis of such well-defined crystallites of hydroxyapatite, is an added advantage of this method, which may be explored further for the scaling up of the procedures to suit to industrial scale synthesis of such hydroxyapatite nanoparticles. - Highlights: • Hydroxyapatite nanoparticles are synthesized using a simple precipitation method. • Both needle-like and spherical hydroxyapatite nanoparticles are synthesized. • The prepared

Facile synthesis of both needle-like and spherical hydroxyapatite nanoparticles: Effect of synthetic temperature and calcination on morphology, crystallite size and crystallinity

Energy Technology Data Exchange (ETDEWEB)

Wijesinghe, W.P.S.L.; Mantilaka, M.M.M.G.P.G. [Department of Chemistry, Faculty of Science, University of Peradeniya, Peradeniya 20400 (Sri Lanka); Post-graduate Institute of Science, P.O. Box: 25, University of Peradeniya, Peradeniya 20400 (Sri Lanka); Premalal, E.V.A. [Department of Materials Science, Shizuoka University, Johoku, Naka-ku Hamamatsu, 432-8011 (Japan); Herath, H.M.T.U. [Department of Medical Laboratory Science, Faculty of Allied Health Sciences, University of Peradeniya, Peradeniya 20400 (Sri Lanka); Mahalingam, S.; Edirisinghe, M. [Department of Mechanical Engineering, University College London, London WC1E 7JE (United Kingdom); Rajapakse, R.P.V.J. [Department of Veterinary Pathobiology, Faculty of Veterinary, University of Peradeniya, Peradeniya 20400 (Sri Lanka); Rajapakse, R.M.G., E-mail: rmgr@pdn.ac.lk [Department of Chemistry, Faculty of Science, University of Peradeniya, Peradeniya 20400 (Sri Lanka); Post-graduate Institute of Science, P.O. Box: 25, University of Peradeniya, Peradeniya 20400 (Sri Lanka)

2014-09-01

Synthetic hydroxyapatite (HA) nanoparticles, that mimic natural HA, are widely used as biocompatible coatings on prostheses to repair and substitute human bones. In this study, HA nanoparticles are prepared by precipitating them from a precursor solution containing calcium sucrate and ammonium dihydrogen orthophosphate, at a Ca/P mole ratio of 1.67:1, at temperatures, ranging from 10 °C to 95 °C. A set of products, prepared at different temperatures, is analyzed for their crystallinity, crystallite size, morphology, thermal stability and composition, by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and Fourier transform infrared (FT-IR) spectroscopic techniques, while the other set is analyzed after calcining the respective products, soon after their synthesis, for 3 h, at 700 °C. The as-prepared products, after 2 h of drying, without any calcination, are not crystalline, but they grow very slowly into needle-like morphologies, as they are ripened with time. The percentage crystallinity of the final products increases from 15% to 52%, with increasing the preparative temperature. The calcined samples always produce spherical nanoparticles of essentially the same diameter, between 90 nm and 100 nm, which does not change due to aging and preparative temperatures. Therefore, the same method can be utilized to synthesize both spherical and needle-like nanoparticles of hydroxyapatite, with well-defined sizes and shapes. The ability to use readily available cheap raw materials, for the synthesis of such well-defined crystallites of hydroxyapatite, is an added advantage of this method, which may be explored further for the scaling up of the procedures to suit to industrial scale synthesis of such hydroxyapatite nanoparticles. - Highlights: • Hydroxyapatite nanoparticles are synthesized using a simple precipitation method. • Both needle-like and spherical hydroxyapatite nanoparticles are synthesized. • The prepared

Comparison of Oxidative Stresses Mediated by Different Crystalline Forms and Surface Modification of Titanium Dioxide Nanoparticles

Directory of Open Access Journals (Sweden)

Karim Samy El-Said

2015-01-01

Full Text Available Titanium dioxide nanoparticles (TiO2 NPs are manufactured worldwide for use in a wide range of applications. There are two common crystalline forms of TiO2 anatase and rutile with different physical and chemical characteristics. We previously demonstrated that an increased DNA damage response is mediated by anatase crystalline form compared to rutile. In the present study, we conjugated TiO2 NPs with polyethylene glycol (PEG in order to reduce the genotoxicity and we evaluated some oxidative stress parameters to obtain information on the cellular mechanisms of DNA damage that operate in response to TiO2 NPs different crystalline forms exposure in hepatocarcinoma cell lines (HepG2. Our results indicated a significant increase in oxidative stress mediated by the anatase form of TiO2 NPs compared to rutile form. On the other hand, PEG modified TiO2 NPs showed a significant decrease in oxidative stress as compared to TiO2 NPs. These data suggested that the genotoxic potential of TiO2 NPs varies with crystalline form and surface modification.

Studying the Kinetics of Crystalline Silicon Nanoparticle Lithiation with In Situ Transmission Electron Microscopy

KAUST Repository

McDowell, Matthew T.; Ryu, Ill; Lee, Seok Woo; Wang, Chongmin; Nix, William D.; Cui, Yi

2012-01-01

In situ transmission electron microscopy (TEM) is used to study the electrochemical lithiation of high-capacity crystalline Si nanoparticles for use in Li-ion battery anodes. The lithiation reaction slows down as it progresses into the particle interior, and analysis suggests that this behavior is due not to diffusion limitation but instead to the influence of mechanical stress on the driving force for reaction. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Studying the Kinetics of Crystalline Silicon Nanoparticle Lithiation with In Situ Transmission Electron Microscopy

KAUST Repository

McDowell, Matthew T.

2012-09-04

In situ transmission electron microscopy (TEM) is used to study the electrochemical lithiation of high-capacity crystalline Si nanoparticles for use in Li-ion battery anodes. The lithiation reaction slows down as it progresses into the particle interior, and analysis suggests that this behavior is due not to diffusion limitation but instead to the influence of mechanical stress on the driving force for reaction. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Approaches to contactless optical thermometer in the NIR spectral range based on Nd{sup 3+} doped crystalline nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Kaldvee, K.; Nefedova, A.V. [Institute of Physics, University of Tartu, W. Ostwaldi st. 1, Tartu 50411 (Estonia); Fedorenko, S.G. [Voevodsky Institute of Chemical Kinetics and Combustion SB RAS, Novosibirsk 630090 (Russian Federation); Vanetsev, A.S. [Institute of Physics, University of Tartu, W. Ostwaldi st. 1, Tartu 50411 (Estonia); Prokhorov General Physics Institute RAS, Vavilov st. 38, Moscow 119991 (Russian Federation); Orlovskaya, E.O. [Prokhorov General Physics Institute RAS, Vavilov st. 38, Moscow 119991 (Russian Federation); Puust, L.; Pärs, M.; Sildos, I. [Institute of Physics, University of Tartu, W. Ostwaldi st. 1, Tartu 50411 (Estonia); Ryabova, A.V. [Prokhorov General Physics Institute RAS, Vavilov st. 38, Moscow 119991 (Russian Federation); National Research Nuclear University Moscow Engineering Physics Institute, Kashirskoe Highway, 31, Moscow 115409 (Russian Federation); Orlovskii, Yu.V., E-mail: orlovski@Lst.gpi.ru [Institute of Physics, University of Tartu, W. Ostwaldi st. 1, Tartu 50411 (Estonia); Prokhorov General Physics Institute RAS, Vavilov st. 38, Moscow 119991 (Russian Federation)

2017-03-15

The fluorescence kinetics and spectral intensity ratio (FIR) methods for contactless optical temperature measurement in the NIR spectral range with Nd{sup 3+} doped YAG micro- and YPO{sub 4} nanocrystals are considered and the problems are revealed. The requirements for good temperature RE doped crystalline nanoparticles sensor are formulated.

γ-Irradiation assisted synthesis of graphene oxide sheets supported Ag nanoparticles with single crystalline structure and parabolic distribution from interlamellar limitation

Energy Technology Data Exchange (ETDEWEB)

Yue, Yunhao; Zhou, Baoming; Shi, Jie; Chen, Cheng; Li, Nan; Xu, Zhiwei, E-mail: xuzhiwei@tjpu.edu.cn; Liu, Liangsen; Kuang, Liyun; Ma, Meijun; Fu, Hongjun

2017-05-01

Highlights: • Graphene oxide sheets supported Ag nanoparticles composites are successfully prepared via γ-irradiation without surfactant or functional agent. • Ag nanoparticles exhibit single crystalline structure and parabolic distribution on the surface of graphene oxide sheets. • Proposing a view that the growth of intercellular AgNPs can be limited by graphite oxide. - Abstract: This paper reported a method to fabricate graphene oxide sheets supported Ag nanoparticles (AgNPs/GOS) with single crystalline structure and parabolic distribution without surfactant or functional agent. We used imidazole silver nitrate as intercalation precursor into the layers of graphite oxide, and subsequently reduction and growth of interlamellar AgNPs were induced via γ-irradiation. The results illustrated that the synergism of interlamellar limitation of graphite oxide and fragmentation ability of γ-irradiation could prevent coalescent reaction of AgNPs with other oligomeric clusters, and the single crystalline and small-sized (below 13.9 nm) AgNPs were prepared. Moreover, the content and size of AgNPs exhibited parabolic distribution on GOS surface because the graphite oxide exfoliated to GOS from the edge to the central area of layers. In addition, complete exfoliation degree of GOS and large-sized AgNPs were obtained simultaneously under suitable silver ions concentration. Optimized composites exhibited outstanding surface-enhanced Raman scattering properties for crystal violet with enhancement factor of 1.3 × 10{sup 6} and detection limit of 1.0 × 10{sup −7} M, indicating that the AgNPs/GOS composites could be applied to trace detection of organic dyes molecules. Therefore, this study presented a strategy for developing GOS supported nanometal with single crystalline structure and parabolic distribution based on γ-irradiation.

γ-Irradiation assisted synthesis of graphene oxide sheets supported Ag nanoparticles with single crystalline structure and parabolic distribution from interlamellar limitation

International Nuclear Information System (INIS)

Yue, Yunhao; Zhou, Baoming; Shi, Jie; Chen, Cheng; Li, Nan; Xu, Zhiwei; Liu, Liangsen; Kuang, Liyun; Ma, Meijun; Fu, Hongjun

2017-01-01

Highlights: • Graphene oxide sheets supported Ag nanoparticles composites are successfully prepared via γ-irradiation without surfactant or functional agent. • Ag nanoparticles exhibit single crystalline structure and parabolic distribution on the surface of graphene oxide sheets. • Proposing a view that the growth of intercellular AgNPs can be limited by graphite oxide. - Abstract: This paper reported a method to fabricate graphene oxide sheets supported Ag nanoparticles (AgNPs/GOS) with single crystalline structure and parabolic distribution without surfactant or functional agent. We used imidazole silver nitrate as intercalation precursor into the layers of graphite oxide, and subsequently reduction and growth of interlamellar AgNPs were induced via γ-irradiation. The results illustrated that the synergism of interlamellar limitation of graphite oxide and fragmentation ability of γ-irradiation could prevent coalescent reaction of AgNPs with other oligomeric clusters, and the single crystalline and small-sized (below 13.9 nm) AgNPs were prepared. Moreover, the content and size of AgNPs exhibited parabolic distribution on GOS surface because the graphite oxide exfoliated to GOS from the edge to the central area of layers. In addition, complete exfoliation degree of GOS and large-sized AgNPs were obtained simultaneously under suitable silver ions concentration. Optimized composites exhibited outstanding surface-enhanced Raman scattering properties for crystal violet with enhancement factor of 1.3 × 10"6 and detection limit of 1.0 × 10"−"7 M, indicating that the AgNPs/GOS composites could be applied to trace detection of organic dyes molecules. Therefore, this study presented a strategy for developing GOS supported nanometal with single crystalline structure and parabolic distribution based on γ-irradiation.

Facile synthesis of both needle-like and spherical hydroxyapatite nanoparticles: effect of synthetic temperature and calcination on morphology, crystallite size and crystallinity.

Science.gov (United States)

Wijesinghe, W P S L; Mantilaka, M M M G P G; Premalal, E V A; Herath, H M T U; Mahalingam, S; Edirisinghe, M; Rajapakse, R P V J; Rajapakse, R M G

2014-09-01

Synthetic hydroxyapatite (HA) nanoparticles, that mimic natural HA, are widely used as biocompatible coatings on prostheses to repair and substitute human bones. In this study, HA nanoparticles are prepared by precipitating them from a precursor solution containing calcium sucrate and ammonium dihydrogen orthophosphate, at a Ca/P mole ratio of 1.67:1, at temperatures, ranging from 10°C to 95°C. A set of products, prepared at different temperatures, is analyzed for their crystallinity, crystallite size, morphology, thermal stability and composition, by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and Fourier transform infrared (FT-IR) spectroscopic techniques, while the other set is analyzed after calcining the respective products, soon after their synthesis, for 3h, at 700°C. The as-prepared products, after 2h of drying, without any calcination, are not crystalline, but they grow very slowly into needle-like morphologies, as they are ripened with time. The percentage crystallinity of the final products increases from 15% to 52%, with increasing the preparative temperature. The calcined samples always produce spherical nanoparticles of essentially the same diameter, between 90 nm and 100 nm, which does not change due to aging and preparative temperatures. Therefore, the same method can be utilized to synthesize both spherical and needle-like nanoparticles of hydroxyapatite, with well-defined sizes and shapes. The ability to use readily available cheap raw materials, for the synthesis of such well-defined crystallites of hydroxyapatite, is an added advantage of this method, which may be explored further for the scaling up of the procedures to suit to industrial scale synthesis of such hydroxyapatite nanoparticles. Copyright © 2014 Elsevier B.V. All rights reserved.

High-resolution electron microscopy study of electron-irradiation-induced crystalline-to-amorphous transition in α-SiC single crystals

International Nuclear Information System (INIS)

Inui, H.; Mori, H.; Sakata, T.

1992-01-01

An electron-irradiation-induced crystalline-to-amorphous (CA) transition in α-SiC has been studied by high-resolution electron microscopy (HREM). The irradiation-produced damage structure was examined as a function of dose of electrons by taking high-resolution maps extending from the unirradiated crystalline region to the completely amorphized region. In the intermediate region between those two regions, that is in the CA transition region, the damage structure was essentially a mixture of crystalline and amorphous phases. The volume fraction of the amorphous phase was found to increase with increasing dose of electrons and no discrete crystalline-amorphous interface was observed in the CA transition region. These facts indicate the heterogeneous and gradual nature of the CA transition. In the transition region close to the unirradiated crystalline region, a sort of fragmentation of the crystal lattice was observed to occur, crystallites with slightly different orientations with respect to the parent crystal were formed owing to the strain around the dispersed local amorphous regions. In the transition region close to the amorphized region, these crystallites were reduced in size and were embedded in an amorphous matrix. This damage structure is the result of the increased volume fraction of the amorphous phase. In the completely amorphized region, no lattice fringes were recognized in the HREM images. The atomistic process of the CA transition is discussed on the basis of the present results and those from previous studies. (Author)

Transport insurance of unirradiated nuclear fuels

International Nuclear Information System (INIS)

Matto, H.

1985-01-01

Special conditions must be taken into account in transport insurance for nuclear materials even if the nuclear risk involved is negligible, as in shipments of unirradiated nuclear fuels. The shipwreck of the 'Mont Louis' has raised a number of open points which must be solved pragmatically within the framework of transport insurance. Some proposals are outlined in the article. (orig.) [de

Temperature dependence of magnetoresistance in neutron-irradiated and unirradiated high resistivity p-type silicon

International Nuclear Information System (INIS)

Yildirim, M.; Efeoglu, H.; Abay, B.; Yogurtcu, Y.K.

1996-01-01

The temperature dependence of the transverse magnetoresistance in irradiated and unirradiated p-type Si is studied in the range from 120 to 290 K. The magnetoresistance coefficients for the unirradiated left angle 001 right angle and left angle 1 anti 10 right angle samples increases with decreasing sample temperature in the range from 160 to 290 K, however, this behavior is reversed below 160 K. It is proposed that this reversal is due to the double injection effect. The magnetoresistance coefficient for the irradiated left angle 001 right angle sample increases with decreasing sample temperature in the range of 120 to 290 K and is greater than that for the unirradiated left angle 001 right angle sample. This result can be explained by increased scattering due to the increased number of defects produced by irradiation. On the other hand, the magnetoresistance coefficient for the unirradiated left angle 1 anti 10 right angle sample is found to be greater than that of the unirradiated left angle 001 right angle sample. (orig.)

Time-dependent growth of crystalline Au0-nanoparticles in cyanobacteria as self-reproducing bioreactors: 2. Anabaena cylindrica

Directory of Open Access Journals (Sweden)

Liz M. Rösken

2016-03-01

Full Text Available Microbial biosynthesis of metal nanoparticles as needed in catalysis has shown its theoretical ability as an extremely environmentally friendly production method in the last few years, even though the separation of the nanoparticles is challenging. Biosynthesis, summing up biosorption and bioreduction of diluted metal ions to zero valent metals, is especially ecofriendly, when the bioreactor itself is harmless and needs no further harmful reagents. The cyanobacterium Anabaena cylindrica (SAG 1403.2 is able to form crystalline Au0-nanoparticles from Au3+ ions and does not release toxic anatoxin-a. X-ray powder diffraction (XRD, transmission electron microscopy (TEM and laser-induced breakdown spectroscopy (LIBS are applied to monitor the time-dependent development of gold nanoparticles for up to 40 hours. Some vegetative cells (VC are filled with nanoparticles within minutes, while the extracellular polymeric substances (EPS of vegetative cells and the heterocyst polysaccharide layer (HEP are the regions, where the first nanoparticles are detected on most other cells. The uptake of gold starts immediately after incubation and within four hours the average size remains constant around 10 nm. Analyzing the TEM images with an image processing program reveals a wide distribution for the diameter of the nanoparticles at all times and in all regions of the cyanobacteria. Finally, the nanoparticle concentration in vegetative cells of Anabaena cylindrica is about 50% higher than in heterocysts (HC. These nanoparticles are found to be located along the thylakoid membranes.

Time-dependent growth of crystalline Au(0)-nanoparticles in cyanobacteria as self-reproducing bioreactors: 2. Anabaena cylindrica.

Science.gov (United States)

Rösken, Liz M; Cappel, Felix; Körsten, Susanne; Fischer, Christian B; Schönleber, Andreas; van Smaalen, Sander; Geimer, Stefan; Beresko, Christian; Ankerhold, Georg; Wehner, Stefan

2016-01-01

Microbial biosynthesis of metal nanoparticles as needed in catalysis has shown its theoretical ability as an extremely environmentally friendly production method in the last few years, even though the separation of the nanoparticles is challenging. Biosynthesis, summing up biosorption and bioreduction of diluted metal ions to zero valent metals, is especially ecofriendly, when the bioreactor itself is harmless and needs no further harmful reagents. The cyanobacterium Anabaena cylindrica (SAG 1403.2) is able to form crystalline Au(0)-nanoparticles from Au(3+) ions and does not release toxic anatoxin-a. X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and laser-induced breakdown spectroscopy (LIBS) are applied to monitor the time-dependent development of gold nanoparticles for up to 40 hours. Some vegetative cells (VC) are filled with nanoparticles within minutes, while the extracellular polymeric substances (EPS) of vegetative cells and the heterocyst polysaccharide layer (HEP) are the regions, where the first nanoparticles are detected on most other cells. The uptake of gold starts immediately after incubation and within four hours the average size remains constant around 10 nm. Analyzing the TEM images with an image processing program reveals a wide distribution for the diameter of the nanoparticles at all times and in all regions of the cyanobacteria. Finally, the nanoparticle concentration in vegetative cells of Anabaena cylindrica is about 50% higher than in heterocysts (HC). These nanoparticles are found to be located along the thylakoid membranes.

Hydrothermal synthesis of highly crystalline RuS{sub 2} nanoparticles as cathodic catalysts in the methanol fuel cell and hydrochloric acid electrolysis

Energy Technology Data Exchange (ETDEWEB)

Li, Yanjuan [Key Laboratory of Marine Chemistry Theory and Technology, Minisry of Education Ocean University of China, Qingdao, 266100 (China); College of Material Science and Engineering, Key Laboratory of Automobile Materials of Ministry of Education, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Li, Nan, E-mail: lin@jlu.edu.cn [College of Material Science and Engineering, Key Laboratory of Automobile Materials of Ministry of Education, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Yanagisawa, Kazumichi [Research Laboratory of Hydrothermal Chemistry, Kochi University, Kochi 780-8520 (Japan); Li, Xiaotian [College of Material Science and Engineering, Key Laboratory of Automobile Materials of Ministry of Education, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Yan, Xiao [Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University, Changchun 130012 (China)

2015-05-15

Highlights: • Highly crystalline RuS{sub 2} nanoparticles have been first synthesized by a “one-step” hydrothermal method. • The product presents a pure cubic phase of stoichiometric ratio RuS{sub 2} with average particle size of 14.8 nm. • RuS{sub 2} nanoparticles were used as cathodic catalysts in methanol fuel cell and hydrochloric acid electrolysis. • The catalyst outperforms commercial Pt/C in methanol tolerance and stability towards Cl{sup −}. - Abstract: Highly crystalline ruthenium sulfide (RuS{sub 2}) nanoparticles have been first synthesized by a “one-step” hydrothermal method at 400 °C, using ruthenium chloride and thiourea as reactants. The products were characterized by powder X-ray diffraction (XRD), scanning electron microscopy/energy disperse spectroscopy (SEM/EDS), thermo gravimetric-differential thermal analyze (TG-DTA), transmission electron microscopy equipped with selected area electron diffraction (TEM/SAED). Fourier transform infrared spectra (IR), and X-ray photoelectron spectroscopy (XPS). XRD result illustrates that the highly crystalline product presents a pure cubic phase of stoichiometric ratio RuS{sub 2} and the average particle size is 14.8 nm. SEM and TEM images display the products have irregular shape of 6–25 nm. XPS analyst indicates that the sulfur exists in the form of S{sub 2}{sup 2−}. Cyclic voltammetry (CV), rotating disk electrode (RDE), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) measurements are conducted to evaluate the electrocatalytic activity and stability of the highly crystalline RuS{sub 2} nanoparticles in oxygen reduction reaction (ORR) for methanol fuel cell and hydrochloric acid electrolysis. The results illustrate that RuS{sub 2} is active towards oxygen reduction reaction. Although the activity of RuS{sub 2} is lower than that of Pt/C, the RuS{sub 2} catalyst outperforms commercial Pt/C in methanol tolerance and stability towards Cl{sup −}.

Influence of Silver and Gold Nanoparticles and Thin Layers on Charge Carrier Generation in InGaN/GaN Multiple Quantum Well Structures and Crystalline Zinc Oxide Films

Science.gov (United States)

Mezdrogina, M. M.; Vinogradov, A. Ya.; Kozhanova, Yu. V.; Levitskii, V. S.

2018-04-01

It has been shown that Ag and Au nanoparticles and thin layers influence charge carrier generation in InGaN/GaN multiple quantum well structures and crystalline ZnO films owing to the surface morphology heterogeneity of the semiconductors. When nanoparticles 10 films, the radiation intensity has turned out to grow considerably because of a plasmon resonance with the participation of localized plasmons. The application of Ag or Au layers on the surface of the structures strongly attenuates the radiation. When Ag and Au nanoparticles are applied on crystalline ZnO films obtained by rf magnetron sputtering, the radiation intensity in the short-wavelength part of the spectrum increases insignificantly because of their highly heterogeneous surface morphology.

Functional recovery in the irradiated kidney following removal of the contralateral unirradiated kidney

International Nuclear Information System (INIS)

Robbins, M.E.C.; Hopewell, J.W.; Golding, S.J.

1986-01-01

Radiation-induced damage to one kidney in the pig causes a fall in total renal function; this would be recognised and lead to a compensatory response in the unirradiated kidney. The presence of the unirradiated contralateral kidney may effectively prevent the irradiated kidney from expressing any potential for repair and/or recovery of function. If this were true then the question would obviously arise, does the irradiated kidney retain some capacity for recovery? In order to answer this question, the contralateral unirradiated kidney was removed from pigs 26 weeks after the irradiation of the other kidney. The subsequent response of the irradiated kidney to nephrectomy was assessed in terms of the changes in renal size and haemodynamics, i.e. GFR and effective renal plasma flow (ERPF). (Auth.)

In vivo genetic toxicity studies in Chinese hamsters fed irradiated or unirradiated foodstuffs

International Nuclear Information System (INIS)

Altmann, H.

1982-01-01

Two in vivo genetic toxicity studies were performed in Chinese hamsters fed irradiated or unirradiated diets of chicken, fish or dates in order to detect possible mutagenic effects caused by irradiating these foodstuffs. The tests selected for study were: 1. Chromosomal analysis of bone narrow cells and 2. DNA metabolism in spleen cells. Chicken, fish and dates were irradiated with doses of 7, 2.5 and 1 kGy respectively. These investigations were subsequently extended to include the effects of irradiated dried onions, pulses and cocoa beans on DNA metabolism in Chinese hamster spleen cells only. Dried onions were irradiated with doses of 0.15, 9 and 15 kGy, pulses with 10 kGy and cocoa beans with 3.2 to 5 kGy. In addition, a fumigated cocoa bean group was included. No significant differences in chromosomal aberration rate were detected between groups fed irradiated or unirradiated diets. Dried dates, whether irradiated or not, showed some evidence of genetic toxicity in their effect on DNA metabolism in the spleen cells of Chinese hamsters. Both date diets caused more strand breaks DNA than are usual for Chinese hamster spleen cells, but DNA repair was not adversely affected. Chicken, both irradiated and unirradiated, was found to enhance replicative DNA synthesis but had no effect on the DNA repair process. Irradiated fish, however, caused enhanced DNA synthesis compared to unirradiated fish, but also had no adverse effect on DNA repair. Irradiated white beans also enhanced DNA synthesis compared to controls whereas unirradiated samples inhibited synthesis. (orig./MG)

Compaction simulation of nano-crystalline metals with molecular dynamics analysis

Directory of Open Access Journals (Sweden)

Khoei A.R.

2016-01-01

Full Text Available The molecular-dynamics analysis is presented for 3D compaction simulation of nano-crystalline metals under uniaxial compaction process. The nano-crystalline metals consist of nickel and aluminum nano-particles, which are mixed with specified proportions. The EAM pair-potential is employed to model the formation of nano-particles at different temperatures, number of nano-particles, and mixing ratio of Ni and Al nano-particles to form the component into the shape of a die. The die-walls are modeled using the Lennard-Jones inter-atomic potential between the atoms of nano-particles and die-walls. The forming process is model in uniaxial compression, which is simulated until the full-dense condition is attained at constant temperature. Numerical simulations are performed by presenting the densification of nano-particles at different deformations and distribution of dislocations. Finally, the evolutions of relative density with the pressure as well as the stress-strain curves are depicted during the compaction process.

A transparent conductive oxide electrode with highly enhanced flexibility achieved by controlled crystallinity by incorporating Ag nanoparticles on substrates

Energy Technology Data Exchange (ETDEWEB)

Triambulo, Ross E.; Cheong, Hahn-Gil [Department of Materials Science and Engineering, Yonsei University, Seoul (Korea, Republic of); Lee, Gun-Hwan [Advanced Thin Film Research Group, Korea Institute of Materials Science (KIMS), Changwon (Korea, Republic of); Yi, In-Sook [R and D Center, InkTec Co., Ltd., Ansan (Korea, Republic of); Park, Jin-Woo, E-mail: jwpark09@yonsei.ac.kr [Department of Materials Science and Engineering, Yonsei University, Seoul (Korea, Republic of)

2015-01-25

Highlights: • We developed a composite transparent electrode with Ag nanoparticles and indium-tin-oxide. • Transmittance of AgNPs was improved by formation of oxide layers by O{sub 2} plasma treatment. • Ag nanoparticles became crystalline seeds to grow strong ITO with a uniform growth orientation. • The hybrid electrode is highly more conductive and stable under bending than ITO. - Abstract: We report the synthesis of highly flexible indium tin oxide (ITO) on a polymer substrate whose surface was engineered by oxide-coated Ag nanoparticles (AgNPs) smaller than 20 nm in diameter. Polyimide (PI) substrates were spin coated with Ag ion ink and were subsequently heat treated to form AgNP coatings. The Ag oxide was formed by O{sub 2} plasma treatment to reduce the light absorbance by AgNPs. ITO was dc magnetron sputter-deposited atop the AgNPs. The ITO on the AgNPs was crystalline grown primarily with (2 2 2) growth orientation. This contrasts to the typical microstructure of ITO grown on the polymer, which is that growing c-ITO nucleates are embedded in an amorphous ITO (a-ITO) matrix like a particulate composite. The surface roughness of ITO on AgNPs was as small as the ITO on PI without AgNPs. The crystalline nature of the ITO on the AgNP-coated polymer resulted in the decrease of electric resistivity (ρ) by 65% compared to that of ITO on the bare PI. Furthermore, an electric resistivity change (Δρ) of the ITO on the AgNPs was only 8% at a bending radius (r{sub b}) down to 4 mm, whereas the ITO on the non-coated polymer became almost insulating at an r{sub b} of 10 mm, owing to a drastic increase in the number of cracks. To validate the potential application in the displays, flexible organic light emitting diodes (f-OLEDs) were fabricated on the ITO on AgNPs and the performances was compared with the f-OLED on ITO on the bare PI.

A transparent conductive oxide electrode with highly enhanced flexibility achieved by controlled crystallinity by incorporating Ag nanoparticles on substrates

International Nuclear Information System (INIS)

Triambulo, Ross E.; Cheong, Hahn-Gil; Lee, Gun-Hwan; Yi, In-Sook; Park, Jin-Woo

2015-01-01

Highlights: • We developed a composite transparent electrode with Ag nanoparticles and indium-tin-oxide. • Transmittance of AgNPs was improved by formation of oxide layers by O 2 plasma treatment. • Ag nanoparticles became crystalline seeds to grow strong ITO with a uniform growth orientation. • The hybrid electrode is highly more conductive and stable under bending than ITO. - Abstract: We report the synthesis of highly flexible indium tin oxide (ITO) on a polymer substrate whose surface was engineered by oxide-coated Ag nanoparticles (AgNPs) smaller than 20 nm in diameter. Polyimide (PI) substrates were spin coated with Ag ion ink and were subsequently heat treated to form AgNP coatings. The Ag oxide was formed by O 2 plasma treatment to reduce the light absorbance by AgNPs. ITO was dc magnetron sputter-deposited atop the AgNPs. The ITO on the AgNPs was crystalline grown primarily with (2 2 2) growth orientation. This contrasts to the typical microstructure of ITO grown on the polymer, which is that growing c-ITO nucleates are embedded in an amorphous ITO (a-ITO) matrix like a particulate composite. The surface roughness of ITO on AgNPs was as small as the ITO on PI without AgNPs. The crystalline nature of the ITO on the AgNP-coated polymer resulted in the decrease of electric resistivity (ρ) by 65% compared to that of ITO on the bare PI. Furthermore, an electric resistivity change (Δρ) of the ITO on the AgNPs was only 8% at a bending radius (r b ) down to 4 mm, whereas the ITO on the non-coated polymer became almost insulating at an r b of 10 mm, owing to a drastic increase in the number of cracks. To validate the potential application in the displays, flexible organic light emitting diodes (f-OLEDs) were fabricated on the ITO on AgNPs and the performances was compared with the f-OLED on ITO on the bare PI

The effect of cetyl palmitate crystallinity on physical properties of gamma-oryzanol encapsulated in solid lipid nanoparticles.

Science.gov (United States)

Ruktanonchai, Uracha; Limpakdee, Surachai; Meejoo, Siwaporn; Sakulkhu, Usawadee; Bunyapraphatsara, Nuntavan; Junyaprasert, Varaporn; Puttipipatkhachorn, Satit

2008-03-05

This present study was aimed at investigating the effect of the crystallinity of cetyl palmitate based solid lipid nanoparticles (SLNs) on the physical properties of γ-oryzanol-loaded SLNs. SLNs consisting of varying ratios of cetyl palmitate and γ-oryzanol were prepared. Their hydrodynamic diameters were in the range 210-280 nm and the zeta potentials were in the range -27 to -35 mV. The size of SLNs increased as the amount of cetyl palmitate decreased whereas no significant change of zeta potentials was found. Atomic force microscopy pictures indicated the presence of disc-like particles. The crystallinity of SLNs, determined by differential scanning calorimetry and powder x-ray diffraction, was directly dependent on the ratio of cetyl palmitate to γ-oryzanol and decreased with decreasing cetyl palmitate content in the lipid matrix. Varying this ratio in the lipid mix resulted in a shift in the melting temperature and enthalpy, although the SLN structure remained unchanged as an orthorhombic lamellar lattice. This has been attributed to a potential inhibition by γ-oryzanol during lipid crystal growth as well as a less ordered structure of the SLNs. The results revealed that the crystallinity of the SLNs was mainly dependent on the solid lipid, and that the crystallinity has an important impact on the physical characteristics of active-loaded SLNs.

The effect of cetyl palmitate crystallinity on physical properties of gamma-oryzanol encapsulated in solid lipid nanoparticles

International Nuclear Information System (INIS)

Ruktanonchai, Uracha; Sakulkhu, Usawadee; Limpakdee, Surachai; Meejoo, Siwaporn; Bunyapraphatsara, Nuntavan; Junyaprasert, Varaporn; Puttipipatkhachorn, Satit

2008-01-01

This present study was aimed at investigating the effect of the crystallinity of cetyl palmitate based solid lipid nanoparticles (SLNs) on the physical properties of γ-oryzanol-loaded SLNs. SLNs consisting of varying ratios of cetyl palmitate and γ-oryzanol were prepared. Their hydrodynamic diameters were in the range 210-280 nm and the zeta potentials were in the range -27 to -35 mV. The size of SLNs increased as the amount of cetyl palmitate decreased whereas no significant change of zeta potentials was found. Atomic force microscopy pictures indicated the presence of disc-like particles. The crystallinity of SLNs, determined by differential scanning calorimetry and powder x-ray diffraction, was directly dependent on the ratio of cetyl palmitate to γ-oryzanol and decreased with decreasing cetyl palmitate content in the lipid matrix. Varying this ratio in the lipid mix resulted in a shift in the melting temperature and enthalpy, although the SLN structure remained unchanged as an orthorhombic lamellar lattice. This has been attributed to a potential inhibition by γ-oryzanol during lipid crystal growth as well as a less ordered structure of the SLNs. The results revealed that the crystallinity of the SLNs was mainly dependent on the solid lipid, and that the crystallinity has an important impact on the physical characteristics of active-loaded SLNs

Self-assembled liquid crystalline nanoparticles as a novel ophthalmic delivery system for dexamethasone: Improving preocular retention and ocular bioavailability.

Science.gov (United States)

Gan, Li; Han, Shun; Shen, Jinqiu; Zhu, Jiabi; Zhu, Chunliu; Zhang, Xinxin; Gan, Yong

2010-08-30

The object of this study was to design novel self-assembled liquid crystalline nanoparticles (cubosomes) as an ophthalmic delivery system for dexamethasone (DEX) to improve its preocular retention and ocular bioavailability. DEX cubosome particles were produced by fragmenting a cubic crystalline phase of monoolein and water in the presence of stabilizer Poloxamer 407. Small angle X-ray diffraction (SAXR) profiles revealed its internal structure as Pn3m space group, indicating the diamond cubic phase. In vitro, the apparent permeability coefficient of DEX administered in cubosomes exhibited a 4.5-fold (F1) and 3.5-fold (F2) increase compared to that of Dex-Na phosphate eye drops. Preocular retention studies revealed that the retention of cubosomes was significantly longer than that of solution and carbopol gel, with AUC(0-->180min) of Rh B cubosomes being 2-3-fold higher than that of the other two formulations. In vivo pharmacokinetics in aqueous humor was evaluated by microdialysis, which indicated a 1.8-fold (F1) increase in AUC(0-->240min) of DEX administered in cubosomes relative to that of Dex-Na phosphate eye drops, with about an 8-fold increase compared to that of DEX suspension. Corneal cross-sections after incubation with DEX cubosomes demonstrated an unaffected corneal structure and tissue integrity, which indicated the good biocompatibility of DEX cubosomes. In conclusion, self-assembled liquid crystalline nanoparticles might represent a promising vehicle for effective ocular drug delivery. Crown Copyright 2010. Published by Elsevier B.V. All rights reserved.

Detection of irradiated spice in blend of irradiated and un-irradiated spices using thermoluminescence method

International Nuclear Information System (INIS)

Goto, Michiko; Yamazaki, Masao; Sekiguchi, Masayuki; Todoriki, Setsuko; Miyahara, Makoto

2007-01-01

Five blended spice sample were prepared by mixing irradiated and un-irradiated black pepper and paprika at different ratios. Blended black pepper containing 2%(w/w) of 5.4 kGy-irradiated black pepper showed no maximum at glow1. Irradiated black pepper samples, mixed to 5 or 10%(w/w), were identified as 'irradiated' or 'partially irradiated' or 'un-irradiated'. All samples with un-irradiated pepper up to 20%(w/w) were identified as irradiated'. In the case 5.0 kGy-irradiated paprika were mixed with un-irradiated paprika up to 5%(w/w), all samples were identified as irradiated'. The glow1 curves of samples, including irradiated paprika at 0.2%(w/w) or higher, exhibited a maximum between 150 and 250degC. The results suggest the existence of different critical mixing ratio for the detection of irradiation among each spices. Temperature range for integration of the TL glow intensity were compared between 70-400degC and approximate 150-250degC, and revealed that the latter temperature range was determined based on the measurement of TLD100. Although TL glow ratio in 150-250degC was lower than that of 70-400degC range, identification of irradiation was not affected. Treatment of un-irradiated black pepper and paprika with ultraviolet rays had no effect on the detection of irradiation. (author)

Combined toxicity of two crystalline phases (anatase and rutile) of Titania nanoparticles towards freshwater microalgae: Chlorella sp

Energy Technology Data Exchange (ETDEWEB)

Iswarya, V.; Bhuvaneshwari, M.; Alex, Sruthi Ann; Iyer, Siddharth; Chaudhuri, Gouri [Centre for Nanobiotechnology, VIT University, Vellore (India); Chandrasekaran, Prathna Thanjavur [Department of Materials Engineering, Indian Institute of Science, Bangalore (India); Bhalerao, Gopalkrishna M.; Chakravarty, Sujoy [UGC-DAE CSR, Kalpakkam Node, Kokilamedu (India); Raichur, Ashok M. [Department of Materials Engineering, Indian Institute of Science, Bangalore (India); Chandrasekaran, N. [Centre for Nanobiotechnology, VIT University, Vellore (India); Mukherjee, Amitava, E-mail: amit.mookerjea@gmail.com [Centre for Nanobiotechnology, VIT University, Vellore (India)

2015-04-15

Highlights: • Toxicity of two crystalline phases of titania NPs on freshwater microalgae studied. • (Anatase, Rutile) mixture showed additive and antagonistic effect on microalgae. • Rutile had more colloidal stability than anatase and binary mixtures. • ROS generation varied with the crystallinity of the NPs. • Ultrastructural damages observed in TEM images. - Abstract: In view of the increasing usage of anatase and rutile crystalline phases of titania NPs in the consumer products, their entry into the aquatic environment may pose a serious risk to the ecosystem. In the present study, the possible toxic impact of anatase and rutile nanoparticles (individually and in binary mixture) was investigated using freshwater microalgae, Chlorella sp. at low exposure concentrations (0.25, 0.5 and 1 mg/L) in freshwater medium under UV irradiation. Reduction of cell viability as well as a reduction in chlorophyll content were observed due to the presence of NPs. An antagonistic effect was noted at certain concentrations of binary mixture such as (0.25, 0.25), (0.25, 0.5), and (0.5, 0.5) mg/L, and an additive effect for the other combinations, (0.25, 1), (0.5, 0.25), (0.5, 1), (1, 0.25), (1, 0.5), and (1, 1) mg/L. The hydrodynamic size analyses in the test medium revealed that rutile NPs were more stable in lake water than the anatase and binary mixtures [at 6 h, the sizes of anatase (1 mg/L), rutile NPs (1 mg/L), and binary mixture (1, 1 mg/L) were 948.83 ± 35.01 nm, 555.74 ± 19.93 nm, and 1620.24 ± 237.87 nm, respectively]. The generation of oxidative stress was found to be strongly dependent on the crystallinity of the nanoparticles. The transmission electron microscopic images revealed damages in the nucleus and cell membrane of algal cells due to the interaction of anatase NPs, whereas rutile NPs were found to cause chloroplast and internal organelle damages. Mis-shaped chloroplasts, lack of nucleus, and starch-pyrenoid complex were noted in binary

Results from In-pile experiments on LWR fuel rod behavior under LOCA conditions with unirradiated rods

International Nuclear Information System (INIS)

Sepold, L.; Karb, E.H.; Pruessmann, M.

1981-06-01

This report summarizes the results of the FR2-in-pile tests at KfK (Kernforschungszentrum Karlsruhe) with unirradiated test rods. The in-pile tests with the objective of investigating the influence of a nuclear environment on the mechanisms of fuel rod failure were being performed with irradiated and unirradiated single rods of a PWR design in the DK loop of the FR2 reactor. The main parameter of the test program was the burnup, ranging from 2.500 to 35.000 MWd/t. The program with unirradiated specimens comprised the series A and B with a total of 14 tests. (orig.) [de

Mechanism of charge transport in ligand-capped crystalline CdTe nanoparticles according to surface photovoltaic and photoacoustic results

Energy Technology Data Exchange (ETDEWEB)

Li Kuiying, E-mail: kuiyingli@ysu.edu.cn [National Laboratory of Metastable Materials Manufacture Technology and Science, Yanshan University, Hebei Str. 438, Qinhuangdao, Hebei Province 066004 (China); Zhang Hao [Key Laboratory for Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012 (China); Yang Weiyong; Wei Sailing [National Laboratory of Metastable Materials Manufacture Technology and Science, Yanshan University, Hebei Str. 438, Qinhuangdao, Hebei Province 066004 (China); Wang Dayang, E-mail: dayang@mpikg-golm.mpg.de [Max Planck Institute of Colloids and Interfaces, Potsdam 14424 (Germany)

2010-09-01

By combining surface photovoltaic and photoacoustic techniques, we probed the photogenerated charge transport channels of 3-mercaptopropionic acid (MPA)- and 2-mercaptoethylamine (MA)-capped crystalline CdTe nanoparticles on illumination with UV-near IR light. The results experimentally confirmed the presence of a CdS shell outside the CdTe core that formed through the self-assembly and decomposition of mercapto ligands during CdTe preparation. The data revealed that the CdS layer was partly responsible for the deexcitation behavior of the photogenerated carriers, which is related to the quantum tunnel effect. Experiments demonstrated that two quantum wells were located at wavelengths of 440 and 500 nm in buried interfacial space-charge regions, whereas the formation of a ligand layer obstructed charge transfer transitions of the core CdTe nanoparticles to a certain extent.

One-pot synthesis of CoNiO2 single-crystalline nanoparticles as high-performance electrode materials of asymmetric supercapacitors

Science.gov (United States)

Du, Weimin; Gao, Yanping; Tian, Qingqing; Li, Dan; Zhang, Zhenhu; Guo, Jiaojiao; Qian, Xuefeng

2015-09-01

A facile one-pot solvothermal method has been developed to synthesize CoNiO2 single-crystalline nanoparticles. Crystal phase, morphology, crystal lattice, and composition of the obtained products were characterized by X-ray diffraction, scanning electron microscope, high-resolution transmission electron microscopy, and energy-dispersive X-ray analysis, respectively. Results revealed that the as-synthesized CoNiO2 nanoparticles belong to cubic structure with narrow size-distribution (8-10 nm). Subsequently, new asymmetric supercapacitors were successfully assembled with CoNiO2 nanoparticles as positive electrode and activated carbon as negative electrode. The electrochemical results show that asymmetric supercapacitors based on CoNiO2 nanoparticles possess excellent supercapacitor properties, i.e., a stable electrochemical window of 0-1.7 V, higher energy density of 24.0 Wh/kg at a power density of 415.4 W/kg, and excellent cycling stability (96.8 % capacitance retention after 5000 charge-discharge cycles). Meanwhile, both a light-emitting diode and a mini fan can be powered by two series connection asymmetric supercapacitors. These results imply that the present asymmetric supercapacitors based on CoNiO2 nanoparticles possess the promising potential application in the field of high-performance energy storage.

One-pot synthesis of CoNiO2 single-crystalline nanoparticles as high-performance electrode materials of asymmetric supercapacitors

International Nuclear Information System (INIS)

Du, Weimin; Gao, Yanping; Tian, Qingqing; Li, Dan; Zhang, Zhenhu; Guo, Jiaojiao; Qian, Xuefeng

2015-01-01

A facile one-pot solvothermal method has been developed to synthesize CoNiO 2 single-crystalline nanoparticles. Crystal phase, morphology, crystal lattice, and composition of the obtained products were characterized by X-ray diffraction, scanning electron microscope, high-resolution transmission electron microscopy, and energy-dispersive X-ray analysis, respectively. Results revealed that the as-synthesized CoNiO 2 nanoparticles belong to cubic structure with narrow size-distribution (8–10 nm). Subsequently, new asymmetric supercapacitors were successfully assembled with CoNiO 2 nanoparticles as positive electrode and activated carbon as negative electrode. The electrochemical results show that asymmetric supercapacitors based on CoNiO 2 nanoparticles possess excellent supercapacitor properties, i.e., a stable electrochemical window of 0–1.7 V, higher energy density of 24.0 Wh/kg at a power density of 415.4 W/kg, and excellent cycling stability (96.8 % capacitance retention after 5000 charge–discharge cycles). Meanwhile, both a light-emitting diode and a mini fan can be powered by two series connection asymmetric supercapacitors. These results imply that the present asymmetric supercapacitors based on CoNiO 2 nanoparticles possess the promising potential application in the field of high-performance energy storage.

Temperature, Crystalline Phase and Influence of Substrate Properties in Intense Pulsed Light Sintering of Copper Sulfide Nanoparticle Thin Films.

Science.gov (United States)

Dexter, Michael; Gao, Zhongwei; Bansal, Shalu; Chang, Chih-Hung; Malhotra, Rajiv

2018-02-02

Intense Pulsed Light sintering (IPL) uses pulsed, visible light to sinter nanoparticles (NPs) into films used in functional devices. While IPL of chalcogenide NPs is demonstrated, there is limited work on prediction of crystalline phase of the film and the impact of optical properties of the substrate. Here we characterize and model the evolution of film temperature and crystalline phase during IPL of chalcogenide copper sulfide NP films on glass. Recrystallization of the film to crystalline covellite and digenite phases occurs at 126 °C and 155 °C respectively within 2-7 seconds. Post-IPL films exhibit p-type behavior, lower resistivity (~10 -3 -10 -4  Ω-cm), similar visible transmission and lower near-infrared transmission as compared to the as-deposited film. A thermal model is experimentally validated, and extended by combining it with a thermodynamic approach for crystal phase prediction and via incorporating the influence of film transmittivity and optical properties of the substrate on heating during IPL. The model is used to show the need to a-priori control IPL parameters to concurrently account for both the thermal and optical properties of the film and substrate in order to obtain a desired crystalline phase during IPL of such thin films on paper and polycarbonate substrates.

Patterning crystalline indium tin oxide by high repetition rate femtosecond laser-induced crystallization

International Nuclear Information System (INIS)

Cheng, Chung-Wei; Lin, Cen-Ying; Shen, Wei-Chih; Lee, Yi-Ju; Chen, Jenq-Shyong

2010-01-01

A method is proposed for patterning crystalline indium tin oxide (c-ITO) patterns on amorphous ITO (a-ITO) thin films by femtosecond laser irradiation at 80 MHz repetition rate followed by chemical etching. In the proposed approach, the a-ITO film is transformed into a c-ITO film over a predetermined area via the heat accumulation energy supplied by the high repetition rate laser beam, and the unirradiated a-ITO film is then removed using an acidic etchant solution. The fabricated c-ITO patterns are observed using scanning electron microscopy and cross-sectional transmission electron microscopy. The crystalline, optical, electrical properties were measured by X-ray diffraction, spectrophotometer, and four point probe station, respectively. The experimental results show that a high repetition rate reduces thermal shock and yields a corresponding improvement in the surface properties of the c-ITO patterns.

One-pot synthesis of CoNiO{sub 2} single-crystalline nanoparticles as high-performance electrode materials of asymmetric supercapacitors

Energy Technology Data Exchange (ETDEWEB)

Du, Weimin, E-mail: dwmchem@163.com; Gao, Yanping; Tian, Qingqing; Li, Dan; Zhang, Zhenhu; Guo, Jiaojiao [Anyang Normal University, College of Chemistry and Chemical Engineering (China); Qian, Xuefeng [Shanghai Jiao Tong University, School of Chemistry and Chemical Technology (China)

2015-09-15

A facile one-pot solvothermal method has been developed to synthesize CoNiO{sub 2} single-crystalline nanoparticles. Crystal phase, morphology, crystal lattice, and composition of the obtained products were characterized by X-ray diffraction, scanning electron microscope, high-resolution transmission electron microscopy, and energy-dispersive X-ray analysis, respectively. Results revealed that the as-synthesized CoNiO{sub 2} nanoparticles belong to cubic structure with narrow size-distribution (8–10 nm). Subsequently, new asymmetric supercapacitors were successfully assembled with CoNiO{sub 2} nanoparticles as positive electrode and activated carbon as negative electrode. The electrochemical results show that asymmetric supercapacitors based on CoNiO{sub 2} nanoparticles possess excellent supercapacitor properties, i.e., a stable electrochemical window of 0–1.7 V, higher energy density of 24.0 Wh/kg at a power density of 415.4 W/kg, and excellent cycling stability (96.8 % capacitance retention after 5000 charge–discharge cycles). Meanwhile, both a light-emitting diode and a mini fan can be powered by two series connection asymmetric supercapacitors. These results imply that the present asymmetric supercapacitors based on CoNiO{sub 2} nanoparticles possess the promising potential application in the field of high-performance energy storage.

ATMP-stabilized iron nanoparticles: chelator-controlled nanoparticle synthesis

Science.gov (United States)

Greenlee, Lauren F.; Rentz, Nikki S.

2014-11-01

In this study, we characterize iron nanoparticles synthesized in water in the presence of a phosphonate chelator, amino tris(methylene phosphonic acid) (ATMP) for a range of molar ratios of ATMP to iron. An increase in the molar ratio from 0.05 to 0.8 decreases nanoparticle size from approximately 150 nm to less than 10 nm. Zeta potential measurements were used to evaluate colloidal stability. Zeta potential values varied as a function of pH, and zeta potential values decreased with increasing pH. At lower molar ratios of ATMP to iron, the zeta potential varied between 15 and -40 mV, passing through an isoelectric point at pH 7.5. At higher ratios, the zeta potential was negative across the measured pH range of 2-12 and varied from -2 to -55 mV. Diffraction analysis indicates that ATMP-stabilized iron nanoparticles may have a nano-crystalline structure, potentially with regions of amorphous iron. Characterization results of ATMP-stabilized iron nanoparticles are compared to results obtained for carboxymethyl cellulose (CMC)-stabilized iron nanoparticles. CMC stabilization caused similar peak broadening in diffraction spectra as for ATMP, suggesting similar nano-crystalline/amorphous structure; however, an increase in the molar ratio of CMC to iron did not cause the same reduction in nanoparticle size as was observed for ATMP-stabilized iron nanoparticles.

Molecular motions of non-crystalline poly(aryl ether-ether-ketone) PEEK and influence of electron beam irradiation

International Nuclear Information System (INIS)

Sasuga, T.; Hagiwara, M.

1985-01-01

The dynamic mechanical relaxation of non-crystalline poly(aryl ether-ether-ketone) PEEK and the one irradiated with electron beam were studied. The three distinct γ, β, α' relaxation maxima were observed in unirradiated PEEK from low to high temperature. It was revealed from the study on the irradiation effects that three different molecular processes are overlapped in γ relaxation peak, i.e., molecular motion of water bound to main chain, local motion of main chain, and local mode of the aligned and/or oriented moiety. The β relaxation connected with the glass transition occurred at 150 deg C and it shifted to higher temperature by irradiation. The α' relaxation which can be attributed to rearrangement of molecular chain due to crystallization was observed in unirradiated PEEK approx. 180 deg C and its magnitude decreased with the increase in irradiation dose. This effect indicates the formation of structures inhibiting crystallization such as crosslinking and/or short branching during irradiation. A new relaxation, β', appeared in the temperature range of 40 deg to 100 deg C by irradiation and its magnitude increased with dose. This relaxation was attributed to rearrangement of molecular chain from loosened packing around chain ends, which were introduced into the non-crystalline region by chain scission under irradiation, to more rigid molecular packing. (author)

Safety analysis report for packaging: the ORNL HFIR unirradiated fuel element shipping container

International Nuclear Information System (INIS)

Evans, J.H.; Boulet, J.A.M.; Eversole, R.E.

1977-11-01

The ORNL HFIR unirradiated fuel element shipping container was designed and fabricated at the Oak Ridge National Laboratory for the transport of HFIR unirradiated fuel elements. The container was evaluated analytically and experimentally to determine its compliance with the applicable regulations governing containers in which radioactive and fissile materials are transported, and the evaluation is the subject of this report. Computational and test procedures were used to determine the structural integrity and thermal behavior of the cask relative to the general standards for normal conditions of transport and the standards for the hypothetical accident conditions. The results of the evaluation demonstrate that the container is in compliance with the applicable regulations

Potential of ITO nanoparticles formed by hydrogen treatment in PECVD for improved performance of back grid contact crystalline silicon solar cell

Energy Technology Data Exchange (ETDEWEB)

Mandal, Sourav; Mitra, Suchismita; Dhar, Sukanta; Ghosh, Hemanta; Banerjee, Chandan, E-mail: chandanbanerjee74@gmail.com; Datta, Swapan K.; Saha, Hiranmoy

2015-09-15

Highlights: • Indium tin oxide (ITO) nanoparticles as back scatterers in c-Si solar cells. • ITO NP have comparatively low dissipative losses and tunable optical properties. • ITO NP formed by hydrogen plasma treatment on sputtered ITO film. • Enhanced absorption and carrier collection at longer wavelengths due to enhanced light trapping. - Abstract: This paper discusses the prospect of using indium tin oxide (ITO) nanoparticles as back scatterers in crystalline silicon solar cells instead of commonly used metal nanoparticles as ITO nanoparticles have comparatively low dissipative losses and tunable optical properties. ITO nanoparticles of ∼5–10 nm size is developed on the rear side of the solar cell by deposition of ∼5–10 nm thick ITO layer by DC magnetron sputtering followed by hydrogen treatment in PECVD. The silicon solar cell is fabricated in the laboratory using conventional method with grid metal contact at the back surface. Various characterizations like FESEM, TEM, AFM, XRD, EQE and IV characteristics are performed to analyze the morphology, chemical composition, optical characteristics and electrical performance of the device. ITO nanoparticles at the back surface of the solar cell significantly enhances the short circuit current, open circuit voltage and efficiency of the solar cell. These enhancements may be attributed to the increased absorption and carrier collection at longer wavelengths of solar spectrum due to enhanced light trapping by the ITO nanoparticles and surface passivation by the hydrogen treatment of the back surface.

Obtaining Highly Crystalline Barium Sulphate Nanoparticles via Chemical Precipitation and Quenching in Absence of Polymer Stabilizers

Directory of Open Access Journals (Sweden)

Ángela B. Sifontes

2015-01-01

Full Text Available Here we report the synthesis of barium sulphate (BaSO4 nanoparticles from Ba(OH2/BaCl2 solutions by a combined method of precipitation and quenching in absence of polymer stabilizers. Transmission electron microscopy (HRTEM, Fourier transforms infrared spectroscopy (FTIR, and X-ray diffraction (XRD were employed to characterize the particles. The Scherrer formula was applied to estimate the particle size using the width of the diffraction peaks. The obtained results indicate that the synthesized material is mainly composed of nanocrystalline barite, with nearly spherical morphology, and diameters ranging from 4 to 92 nm. The lattice images of nanoparticles were clearly observed by HRTEM, indicating a high degree of crystallinity and phase purity. In addition, agglomerates with diameters between 20 and 300 nm were observed in both lattice images and dynamic light scattering measurements. The latter allowed obtaining the particle size distribution, the evolution of the aggregate size in time of BaSO4 in aqueous solutions, and the sedimentation rate of these solutions from turbidimetry measurements. A short discussion on the possible medical applications is presented.

Rescue Effects: Irradiated Cells Helped by Unirradiated Bystander Cells

Science.gov (United States)

Lam, R. K. K.; Fung, Y. K.; Han, W.; Yu, K. N.

2015-01-01

The rescue effect describes the phenomenon where irradiated cells or organisms derive benefits from the feedback signals sent from the bystander unirradiated cells or organisms. An example of the benefit is the mitigation of radiation-induced DNA damages in the irradiated cells. The rescue effect can compromise the efficacy of radioimmunotherapy (RIT) (and actually all radiotherapy). In this paper, the discovery and subsequent confirmation studies on the rescue effect were reviewed. The mechanisms and the chemical messengers responsible for the rescue effect studied to date were summarized. The rescue effect between irradiated and bystander unirradiated zebrafish embryos in vivo sharing the same medium was also described. In the discussion section, the mechanism proposed for the rescue effect involving activation of the nuclear factor κB (NF-κB) pathway was scrutinized. This mechanism could explain the promotion of cellular survival and correct repair of DNA damage, dependence on cyclic adenosine monophosphate (cAMP) and modulation of intracellular reactive oxygen species (ROS) level in irradiated cells. Exploitation of the NF-κB pathway to improve the effectiveness of RIT was proposed. Finally, the possibility of using zebrafish embryos as the model to study the efficacy of RIT in treating solid tumors was also discussed. PMID:25625514

A highway accident involving unirradiated nuclear fuel in Springfield, Massachusetts, on December 16, 1991

International Nuclear Information System (INIS)

Carlson, R.W.; Fischer, L.E.

1992-06-01

In the early morning of Dec. 16, 1991, a severe accident occurred when a passenger vehicle traveling in the wrong direction collided with a tractor trailer carrying 24 unirradiated nuclear fuel assemblies in 12 containers on Interstate I-91 in Springfield, Massachusetts. The purpose of this report is to document the mechanical circumstances of the severe accident, confirm the nature and quantity of the radioactive materials involved, and assess the physical environment to which the containers were exposed and the response of the containers and their contents. The report consists of five major sections. The first section describes the circumstances and conditions of the accident and the finding of facts. The second describes the containers, the unirradiated nuclear fuel assemblies, and the tie down arrangement used for the trailer. The third describes the damage sustained during the accident to the tractor, trailer, containers, and unirradiated nuclear fuel assemblies. The fourth evaluates the accident environment and its effects on the containers and their contents. The final section gives conclusions derived from the analysis and fact finding investigation. During this severe accident, only minor injuries occurred, and at no time was the public health and safety at risk

Highly crystalline zinc incorporated hydroxyapatite nanorods' synthesis, characterization, thermal, biocompatibility, and antibacterial study

Science.gov (United States)

Udhayakumar, Gayathri; Muthukumarasamy, N.; Velauthapillai, Dhayalan; Santhosh, Shanthi Bhupathi

2017-10-01

Highly crystalline zinc incorporated hydroxyapatite (Zn-HAp) nanorods have been synthesized using microwave irradiation method. To improve bioactivity and crystallinity of pure HAp, zinc was incorporated into it. As-synthesized samples were characterized by Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction, field-emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDAX), high-resolution transmission electron microscopy (HRTEM), and the thermal and crystallinity behavior of Zn-HAp nanoparticle were studied by thermogravimetry (TGA) and differential scanning calorimetry (DSC). Antibacterial activity of the as-synthesized nanorods was evaluated against two prokaryotic strains ( Escherichia coli and Staphylococcus aureus). The FT-IR studies show the presence of hydroxide and phosphate functional groups. HRTEM and FESEM images showed highly crystalline rod-shaped nanoparticles with the diameter of about 50-60 nm. EDAX revealed the presence of Ca, Zn, P, and O in the prepared samples. The crystallinity and thermal stability were further confirmed by TGA-DSC analysis. The biocompatibility evaluation results promoted that the Zn-HAp nanorods are biologically active apatites and potentially promising bone-substitute biomaterials for orthopaedic application.

Stress corrosion crack growth in unirradiated zircaloy

International Nuclear Information System (INIS)

Pettersson, K.

1978-10-01

Experimental techniques suitable for the determination of stress corrosion crack growth rates in irradiated Zircaloy tube have been developed. The techniques have been tested on unirradiated. Zircaloy and it was found that the results were in good agreement with the results of other investigations. Some of the results were obtained at very low stress intensities and the crack growth rates observed, gave no indication of the existance of a K sub(ISCC) for iodine induced stress corrosion cracking in Zircaloy. This is of importance both for fuel rod behavior after a power ramp and for long term storage of spent Zircaloy-clad fuel. (author)

Unirradiated cladding rip-propagation tests

International Nuclear Information System (INIS)

Hu, W.L.; Hunter, C.W.

1981-04-01

The size of cladding rips which develop when a fuel pin fails can affect the subassembly cooling and determine how rapidly fuel escapes from the pin. The object of the Cladding Rip Propagation Test (CRPT) was to quantify the failure development of cladding so that a more realistic fuel pin failure modeling may be performed. The test results for unirradiated 20% CS 316 stainless steel cladding show significantly different rip propagation behavior at different temperatures. At room temperature, the rip growth is stable as the rip extension increases monotonically with the applied deformation. At 500 0 C, the rip propagation becomes unstable after a short period of stable rip propagation. The rapid propagation rate is approximately 200 m/s, and the critical rip length is 9 mm. At test temperatures above 850 0 C, the cladding exhibits very high failure resistances, and failure occurs by multiple cracking at high cladding deformation. 13 figures

MOS structures containing silicon nanoparticles for memory device applications

International Nuclear Information System (INIS)

Nedev, N; Zlatev, R; Nesheva, D; Manolov, E; Levi, Z; Brueggemann, R; Meier, S

2008-01-01

Metal-oxide-silicon structures containing layers with amorphous or crystalline silicon nanoparticles in a silicon oxide matrix are fabricated by sequential physical vapour deposition of SiO x (x = 1.15) and RF sputtering of SiO 2 on n-type crystalline silicon, followed by high temperature annealing in an inert gas ambient. Depending on the annealing temperature, 700 deg. C or 1000 deg. C, amorphous or crystalline silicon nanoparticles are formed in the silicon oxide matrix. The annealing process is used not only for growing nanoparticles but also to form a dielectric layer with tunnelling thickness at the silicon/insulator interface. High frequency C-V measurements demonstrate that both types of structures can be charged negatively or positively by applying a positive or negative voltage on the gate. The structures with amorphous silicon nanoparticles show several important advantages compared to the nanocrystal ones, such as lower defect density at the interface between the crystalline silicon wafer and the tunnel silicon oxide, better retention characteristics and better reliability

Growth and Brilliant Photo-Emission of Crystalline Hexagonal Column of Alq3 Microwires

OpenAIRE

Seokho Kim; Do Hyoung Kim; Jinho Choi; Hojin Lee; Sun-Young Kim; Jung Woon Park; Dong Hyuk Park

2018-01-01

We report the growth and nanoscale luminescence characteristics of 8-hydroxyquinolinato aluminum (Alq3) with a crystalline hexagonal column morphology. Pristine Alq3 nanoparticles (NPs) were prepared using a conventional reprecipitation method. Crystal hexagonal columns of Alq3 were grown by using a surfactant-assisted self-assembly technique as an adjunct to the aforementioned reprecipitation method. The formation and structural properties of the crystalline and non-crystalline Alq3 NPs were...

High Temperature Tensile Properties of Unirradiated and Neutron Irradiated 20 Cr-35 Ni Austenitic Steel

Energy Technology Data Exchange (ETDEWEB)

Roy, R B; Solly, B

1966-12-15

The tensile properties of an unirradiated and neutron irradiated (at 40 deg C) 20 % Cr, 35 % Ni austenitic steel have been studied at 650 deg C, 750 deg C and 820 deg C. The tensile elongation and mode of fracture (transgranular) of unirradiated specimens tested at room temperature and 650 deg C are almost identical. At 750 deg C and 820 deg C the elongation decreases considerably and a large part of the total elongation is non-uniform. Furthermore, the mode of fracture at these temperatures is intergranular and microscopic evidence suggests that fracture is caused by formation and linkup of grain boundary cavities. YS and UTS decrease monotonically with temperature. Irradiated specimens show a further decrease in ductility and an increase in the tendency to grain boundary cracking. Irradiation has no significant effect on the YS, but the UTS are reduced. The embrittlement of the irradiated specimens is attributed to the presence of He and Li atoms produced during irradiation and the possible mechanisms are discussed. Prolonged annealing of irradiated and unirradiated specimens at 650 deg C appears to have no significant effect on tensile properties.

Structure, morphology, and magnetic properties of Fe nanoparticles deposited onto single-crystalline surfaces

Directory of Open Access Journals (Sweden)

Armin Kleibert

2011-01-01

Full Text Available Background: Magnetic nanostructures and nanoparticles often show novel magnetic phenomena not known from the respective bulk materials. In the past, several methods to prepare such structures have been developed – ranging from wet chemistry-based to physical-based methods such as self-organization or cluster growth. The preparation method has a significant influence on the resulting properties of the generated nanostructures. Taking chemical approaches, this influence may arise from the chemical environment, reaction kinetics and the preparation route. Taking physical approaches, the thermodynamics and the kinetics of the growth mode or – when depositing preformed clusters/nanoparticles on a surface – the landing kinetics and subsequent relaxation processes have a strong impact and thus need to be considered when attempting to control magnetic and structural properties of supported clusters or nanoparticles.Results: In this contribution we focus on mass-filtered Fe nanoparticles in a size range from 4 nm to 10 nm that are generated in a cluster source and subsequently deposited onto two single crystalline substrates: fcc Ni(111/W(110 and bcc W(110. We use a combined approach of X-ray magnetic circular dichroism (XMCD, reflection high energy electron diffraction (RHEED and scanning tunneling microscopy (STM to shed light on the complex and size-dependent relation between magnetic properties, crystallographic structure, orientation and morphology. In particular XMCD reveals that Fe particles on Ni(111/W(110 have a significantly lower (higher magnetic spin (orbital moment compared to bulk iron. The reduced spin moments are attributed to the random particle orientation being confirmed by RHEED together with a competition of magnetic exchange energy at the interface and magnetic anisotropy energy in the particles. The RHEED data also show that the Fe particles on W(110 – despite of the large lattice mismatch between iron and tungsten – are

Biphenyl liquid crystalline epoxy resin as a low-shrinkage resin-based dental restorative nanocomposite.

Science.gov (United States)

Hsu, Sheng-Hao; Chen, Rung-Shu; Chang, Yuan-Ling; Chen, Min-Huey; Cheng, Kuo-Chung; Su, Wei-Fang

2012-11-01

Low-shrinkage resin-based photocurable liquid crystalline epoxy nanocomposite has been investigated with regard to its application as a dental restoration material. The nanocomposite consists of an organic matrix and an inorganic reinforcing filler. The organic matrix is made of liquid crystalline biphenyl epoxy resin (BP), an epoxy resin consisting of cyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (ECH), the photoinitiator 4-octylphenyl phenyliodonium hexafluoroantimonate and the photosensitizer champhorquinone. The inorganic filler is silica nanoparticles (∼70-100 nm). The nanoparticles were modified by an epoxy silane of γ-glycidoxypropyltrimethoxysilane to be compatible with the organic matrix and to chemically bond with the organic matrix after photo curing. By incorporating the BP liquid crystalline (LC) epoxy resin into conventional ECH epoxy resin, the nanocomposite has improved hardness, flexural modulus, water absorption and coefficient of thermal expansion. Although the incorporation of silica filler may dilute the reinforcing effect of crystalline BP, a high silica filler content (∼42 vol.%) was found to increase the physical and chemical properties of the nanocomposite due to the formation of unique microstructures. The microstructure of nanoparticle embedded layers was observed in the nanocomposite using scanning and transmission electron microscopy. This unique microstructure indicates that the crystalline BP and nanoparticles support each other and result in outstanding mechanical properties. The crystalline BP in the LC epoxy resin-based nanocomposite was partially melted during exothermic photopolymerization, and the resin expanded via an order-to-disorder transition. Thus, the post-gelation shrinkage of the LC epoxy resin-based nanocomposite is greatly reduced, ∼50.6% less than in commercialized methacrylate resin-based composites. This LC epoxy nanocomposite demonstrates good physical and chemical properties and good biocompatibility

Room-temperature deposition of crystalline patterned ZnO films by confined dewetting lithography

International Nuclear Information System (INIS)

Sepulveda-Guzman, S.; Reeja-Jayan, B.; De la Rosa, E.; Ortiz-Mendez, U.; Reyes-Betanzo, C.; Cruz-Silva, R.; Jose-Yacaman, M.

2010-01-01

In this work patterned ZnO films were prepared at room-temperature by deposition of ∼5 nm size ZnO nanoparticles using confined dewetting lithography, a process which induces their assembly, by drying a drop of ZnO colloidal dispersion between a floating template and the substrate. Crystalline ZnO nanoparticles exhibit a strong visible (525 nm) light emission upon UV excitation (λ = 350 nm). The resulting films were characterized by scanning electron microscopy (SEM) and atomic force microscope (AFM). The method described herein presents a simple and low cost method to prepare crystalline ZnO films with geometric patterns without additional annealing. Such transparent conducting films are attractive for applications like light emitting diodes (LEDs). As the process is carried out at room temperature, the patterned crystalline ZnO films can even be deposited on flexible substrates.

Room-temperature deposition of crystalline patterned ZnO films by confined dewetting lithography

Energy Technology Data Exchange (ETDEWEB)

Sepulveda-Guzman, S., E-mail: selene.sepulvedagz@uanl.edu.mx [Centro de Innovacion, Investigacion y Desarrollo en Ingenieria y Tecnologia. UANL, PIIT Monterrey, CP 66629, Apodaca NL (Mexico); Reeja-Jayan, B. [Texas Materials Institute, University of Texas at Austin, Austin, TX 78712 (United States); De la Rosa, E. [Centro de Investigacion en Optica, Loma del Bosque 115 Col. Lomas del Campestre C.P. 37150 Leon, Gto. Mexico (Mexico); Ortiz-Mendez, U. [Centro de Innovacion, Investigacion y Desarrollo en Ingenieria y Tecnologia. UANL, PIIT Monterrey, CP 66629, Apodaca NL (Mexico); Reyes-Betanzo, C. [Instituto Nacional de Astrofisica Optica y Electronica, Calle Luis Enrique Erro No. 1, Santa Maria Tonanzintla, Puebla. Apdo. Postal 51 y 216, C.P. 72000 Puebla (Mexico); Cruz-Silva, R. [Centro de Investigacion en Ingenieria y Ciencias Aplicadas, UAEM. Av. Universidad 1001, Col. Chamilpa, CP 62210 Cuernavaca, Mor. (Mexico); Jose-Yacaman, M. [Physics and Astronomy Department University of Texas at San Antonio 1604 campus San Antonio, TX 78249 (United States)

2010-03-15

In this work patterned ZnO films were prepared at room-temperature by deposition of {approx}5 nm size ZnO nanoparticles using confined dewetting lithography, a process which induces their assembly, by drying a drop of ZnO colloidal dispersion between a floating template and the substrate. Crystalline ZnO nanoparticles exhibit a strong visible (525 nm) light emission upon UV excitation ({lambda} = 350 nm). The resulting films were characterized by scanning electron microscopy (SEM) and atomic force microscope (AFM). The method described herein presents a simple and low cost method to prepare crystalline ZnO films with geometric patterns without additional annealing. Such transparent conducting films are attractive for applications like light emitting diodes (LEDs). As the process is carried out at room temperature, the patterned crystalline ZnO films can even be deposited on flexible substrates.

Synthesis of Ag and Au nanoparticles embedded in carbon film: Optical, crystalline and topography analysis

Science.gov (United States)

Gholamali, Hediyeh; Shafiekhani, Azizollah; Darabi, Elham; Elahi, Seyed Mohammad

2018-03-01

Atomic force microscopy (AFM) images give valuable information about surface roughness of thin films based on the results of power spectral density (PSD) through the fast Fourier transform (FFT) algorithms. In the present work, AFM data are studied for silver and gold nanoparticles (Ag NPs a-C: H and Au NPs a-C: H) embedded in amorphous hydrogenated carbon films and co-deposited on glass substrate via of RF-Sputtering and RF-Plasma Enhanced Chemical Vapor Deposition methods. Here, the working gas is acetylene and the targets are Ag and Au. While time and power are constant, the only variable parameter in this study is initial pressure. In addition, the crystalline structure of Ag NPs a-C: H and Au NPs a-C: H are studied using X-ray diffraction (XRD). UV-visible spectrophotometry will also investigate optical properties and localized surface plasmon resonance (LSPR) of samples.

Hydrothermal synthesis of hydroxyapatite nanoparticles decorated with silver nanoparticles for application in biomaterials

International Nuclear Information System (INIS)

Assis, Jordanna Fernandes; Arantes, Tatiane Moraes; Cristovan, F.H.; Tada, Dayane Batista

2016-01-01

Full text: The hydroxyapatite nanoparticles (HA) have research attention because are material that exhibit biocompatibility with bone mineral phase of human body is great interest in the scientific community. Synthetic hydroxyapatite nanoparticles have excellent biocompatibility and bioactivity, due biocompatibility and osteo inducibility [1-3]. The hydroxyapatite nanoparticles were synthesized by hydrothermal processing and were characterized by X-ray diffraction (XRD), Raman spectroscopy and transmission electron microscopy (TEM). The XRD and Raman spectra showed crystalline hydroxyapatite colloidal nanoparticles were obtained in the hexagonal phase. XRD measure showed silver diffraction peaks cubic phase confirmed the presence of the silver nanoparticles decorated hydroxyapatite surface. TEM images showed HA nanoparticles presented a well defined nanorod shapes and narrow size distributions with dimensions (width and length) around of 5 nm and 50 nm decorated with silver nanoparticles of spherical shape about 20 nm in diameter The results showed that crystalline hydroxyapatite colloidal nanoparticles with rod-like morphology and uniform decorated with silver spherical nanoparticles size were obtained by hydrothermal synthesis. These nanoparticles The cell viability of the HA and HA/Ag was analyzed by reduction of the tetrazolium salt (MTT test). Embryonic mouse fibroblast cells were grown in the presence of nanoparticles for a total period of 96 hours. Analyses were made in 24h, 48h, 72h and 96h. The suspensions at the end of each period were analyzed in spectrophotometer. The 24h experiments were the most conclusive, with the silver presence in the HA, there is an increased in cellular proliferation. The results demonstrated that the HA/Ag nanoparticles have potential use as biomaterials in medical/odontological applications. (author)

Hydrothermal synthesis of hydroxyapatite nanoparticles decorated with silver nanoparticles for application in biomaterials

Energy Technology Data Exchange (ETDEWEB)

Assis, Jordanna Fernandes; Arantes, Tatiane Moraes, E-mail: fernandes.jordanna9@gmail.com [Universidade Federal de Goias (UFG), Goiania (Brazil); Cristovan, F.H.; Tada, Dayane Batista [Universidade Federal de Sao Paulo (UNIFESP), Sao Jose dos Campos, SP (Brazil)

2016-07-01

Full text: The hydroxyapatite nanoparticles (HA) have research attention because are material that exhibit biocompatibility with bone mineral phase of human body is great interest in the scientific community. Synthetic hydroxyapatite nanoparticles have excellent biocompatibility and bioactivity, due biocompatibility and osteo inducibility [1-3]. The hydroxyapatite nanoparticles were synthesized by hydrothermal processing and were characterized by X-ray diffraction (XRD), Raman spectroscopy and transmission electron microscopy (TEM). The XRD and Raman spectra showed crystalline hydroxyapatite colloidal nanoparticles were obtained in the hexagonal phase. XRD measure showed silver diffraction peaks cubic phase confirmed the presence of the silver nanoparticles decorated hydroxyapatite surface. TEM images showed HA nanoparticles presented a well defined nanorod shapes and narrow size distributions with dimensions (width and length) around of 5 nm and 50 nm decorated with silver nanoparticles of spherical shape about 20 nm in diameter The results showed that crystalline hydroxyapatite colloidal nanoparticles with rod-like morphology and uniform decorated with silver spherical nanoparticles size were obtained by hydrothermal synthesis. These nanoparticles The cell viability of the HA and HA/Ag was analyzed by reduction of the tetrazolium salt (MTT test). Embryonic mouse fibroblast cells were grown in the presence of nanoparticles for a total period of 96 hours. Analyses were made in 24h, 48h, 72h and 96h. The suspensions at the end of each period were analyzed in spectrophotometer. The 24h experiments were the most conclusive, with the silver presence in the HA, there is an increased in cellular proliferation. The results demonstrated that the HA/Ag nanoparticles have potential use as biomaterials in medical/odontological applications. (author)

Effect of annealing on the structure of chemically synthesized SnO_2 nanoparticles

International Nuclear Information System (INIS)

Singh, Kulwinder; Kumar, Akshay; Kumar, Virender; Vij, Ankush; Kumari, Sudesh; Thakur, Anup

2016-01-01

Tin oxide (SnO_2) nanoparticles have been synthesized by co-precipitation method. The synthesized nanoparticles were characterized by X-ray diffraction (XRD) and Raman spectroscopy. XRD analysis confirmed the single phase formation of SnO_2 nanoparticles. The Raman shifts showed the typical feature of the tetragonal phase of the as-synthesized SnO_2 nanoparticles. At low annealing temperature, a strong distortion of the crystalline structure and high degree of agglomeration was observed. It is concluded that the crystallinity of SnO_2 nanoparticles improves with the increase in annealing temperature.

Effect of hydroxyapatite particle size, morphology and crystallinity on proliferation of colon cancer HCT116 cells

Energy Technology Data Exchange (ETDEWEB)

Dey, Sangeeta; Das, Mitun, E-mail: mitun@cgcri.res.in; Balla, Vamsi Krishna

2014-06-01

The aim of the present work is to chemically and physically characterize the synthesized Hydroxyapatite (HAp) micro and nanoparticles and to explore the inhibitory effect of nano-HAps on the in vitro growth of human colon cancerous cells HCT116. HAp powder was synthesized using three different routes to achieve micro and nanosized powders, with different morphologies and crystallinity. The synthesized powders were characterized using X-ray diffraction, FTIR spectroscopy and scanning electron microscope. The results showed that the average crystallite size of HAp powder varies from 11 nm to 177 nm and respective crystallinity of powder found to be in the range of 0.12 and 0.92. The effect of these physico-chemical properties of HAp powders on human colon cancer HCT116 cells inhibition was determined in vitro. It was found that decreasing the HAp powder crystallite size between 11 nm and 22 nm significantly increases the HCT116 cell inhibition. Our results demonstrate that apart from HAp powder size their crystallinity and morphology also play an important role in cellular inhibition of human colon cancer cells. - Highlights: • Chemically synthesized hydroxyapatite micro and nano-particles with different morphologies and crystallinity. • In vitro cell–material interaction showed that hydroxyapatite nano-particles inhibit colon cancer cells. • Human colon cancer cell inhibition also depends on crystallinity and morphology of HAp powder.

Entrapment of curcumin into monoolein-based liquid crystalline nanoparticle dispersion for enhancement of stability and anticancer activity

Directory of Open Access Journals (Sweden)

Baskaran R

2014-06-01

Full Text Available Rengarajan Baskaran,1 Thiagarajan Madheswaran,2 Pasupathi Sundaramoorthy,1 Hwan Mook Kim,1 Bong Kyu Yoo1 1College of Pharmacy, Gachon University, Incheon, South Korea; 2College of Pharmacy Yeungnam University, Gyeongsan, South Korea Abstract: Despite the promising anticancer potential of curcumin, its therapeutic application has been limited, owing to its poor solubility, bioavailability, and chemical fragility. Therefore, various formulation approaches have been attempted to address these problems. In this study, we entrapped curcumin into monoolein (MO-based liquid crystalline nanoparticles (LCNs and evaluated the physicochemical properties and anticancer activity of the LCN dispersion. The results revealed that particles in the curcumin-loaded LCN dispersion were discrete and monodispersed, and that the entrapment efficiency was almost 100%. The stability of curcumin in the dispersion was surprisingly enhanced (about 75% of the curcumin survived after 45 days of storage at 40°C, and the in vitro release of curcumin was sustained (10% or less over 15 days. Fluorescence-activated cell sorting (FACS analysis using a human colon cancer cell line (HCT116 exhibited 99.1% fluorescence gating for 5 µM curcumin-loaded LCN dispersion compared to 1.36% for the same concentration of the drug in dimethyl sulfoxide (DMSO, indicating markedly enhanced cellular uptake. Consistent with the enhanced cellular uptake of curcumin-loaded LCNs, anticancer activity and cell cycle studies demonstrated apoptosis induction when the cells were treated with the LCN dispersion; however, there was neither noticeable cell death nor significant changes in the cell cycle for the same concentration of the drug in DMSO. In conclusion, entrapping curcumin into MO-based LCNs may provide, in the future, a strategy for overcoming the hurdles associated with both the stability and cellular uptake issues of the drug in the treatment of various cancers. Keywords: liquid

Thermogravimetric studies of the thermo-oxidative stability of irradiated and unirradiated polyethylene

International Nuclear Information System (INIS)

Novakovic, L.; Gal, O.; Markovic, V.; Stannett, V.T.

1985-01-01

In part one of this series the effects of a phenolic, an amine and a thioester antioxidant on the thermo-oxidative stability of irradiated and unirradiated low-density polyethylene was reported. In this paper the effects of combined phenolic and thioester stabilizers are described. Isothermal thermogravimetric analysis was used to study the systems. Pronounced synergism was observed with the induction periods, the time when the initial weight loss begins and the 5% weight loss. At about 50% of each stabilizer increases greater than twofold were observed both with the unirradiated and irradiated polymers. The rate constants for oxygen uptake were decreased. However, the rates of degradation at 5% weight loss fell between the values of the two pure stabilizers with no pronounced synergism in either case. In the absence of oxygen little effect of either antioxidant or their mixtures was observed. The corresponding activation energies were somewhat higher, however, with the irradiated samples containing antioxidants. Dynamic thermogravimetry was used for this study. A kinetic analysis indicated that there were somewhat different modes of degradation at lower- and higher-temperature ranges. (author)

Effect of substrate bias on deposition behaviour of charged silicon nanoparticles in ICP-CVD process

International Nuclear Information System (INIS)

Yoo, Seung-Wan; Kim, Jung-Hyung; Seong, Dae-Jin; You, Shin-Jae; Seo, Byong-Hoon; Hwang, Nong-Moon

2017-01-01

The effect of a substrate bias on the deposition behaviour of crystalline silicon films during inductively coupled plasma chemical vapour deposition (ICP-CVD) was analysed by consideration of non-classical crystallization, in which the building block is a nanoparticle rather than an individual atom or molecule. The coexistence of positively and negatively charged nanoparticles in the plasma and their role in Si film deposition are confirmed by applying bias voltages to the substrate, which is sufficiently small as not to affect the plasma potential. The sizes of positively and negatively charged nanoparticles captured on a carbon membrane and imaged using TEM are, respectively, 2.7–5.5 nm and 6–13 nm. The film deposited by positively charged nanoparticles has a typical columnar structure. In contrast, the film deposited by negatively charged nanoparticles has a structure like a powdery compact with the deposition rate about three times higher than that for positively charged nanoparticles. All the films exhibit crystallinity even though the substrate is at room temperature, which is attributed to the deposition of crystalline nanoparticles formed in the plasma. The film deposited by negatively charged nanoparticles has the highest crystalline fraction of 0.84. (paper)

Solution-Processible Crystalline NiO Nanoparticles for High-Performance Planar Perovskite Photovoltaic Cells.

Science.gov (United States)

Kwon, Uisik; Kim, Bong-Gi; Nguyen, Duc Cuong; Park, Jong-Hyeon; Ha, Na Young; Kim, Seung-Joo; Ko, Seung Hwan; Lee, Soonil; Lee, Daeho; Park, Hui Joon

2016-07-28

In this work, we report on solution-based p-i-n-type planar-structured CH3NH3PbI3 perovskite photovoltaic (PV) cells, in which precrystallized NiO nanoparticles (NPs) without post-treatment are used to form a hole transport layer (HTL). X-ray diffraction and high-resolution transmission electron microscopy showed the crystallinity of the NPs, and atomic force microscopy and scanning electron microscopy confirmed the uniform surfaces of the resultant NiO thin film and the subsequent perovskite photoactive layer. Compared to the conventional poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) ( PSS) HTL, the NiO HTL had excellent energy-level alignment with that of CH3NH3PbI3 and improved electron-blocking capability, as analyzed by photoelectron spectroscopy and diode modeling, resulting in Voc ~0.13 V higher than conventional PSS-based devices. Consequently, a power conversion efficiency (PCE) of 15.4% with a high fill factor (FF, 0.74), short-circuit current density (Jsc, 20.2 mA·cm(-2)), and open circuit voltage (Voc, 1.04 V) having negligible hysteresis and superior air stability has been achieved.

Characterization of un-irradiated and irradiated reactor graphite; Karakterizacija neozracenog i ozracenog reaktorskog grafita

Energy Technology Data Exchange (ETDEWEB)

Marinkovic, S [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Yugoslavia)

1965-11-15

This report contains three parts: characterization of Yugoslav nuclear graphite development of methods and obtained results, characterization of un-irradiated and irradiated domestic nuclear graphite; calculation of electrical conductivity changes due to vacancies in the graphite crystal lattice.

In-Situ Synchrotron Radiation Study of Formation and Growth of Crystalline CexZr1-xO2 Nanoparticles Synthesized in Supercritical Water

DEFF Research Database (Denmark)

Tyrsted, Christoffer; Becker-Christensen, Jacob; Hald, Peter

2010-01-01

-zirconia system, the growth of ceria and zirconia nanoparticles is fundamentally different under supercritical water conditions. For comparison, ex situ synthesis has also been performed using an in-house supercritical flow reactor. The resulting samples were analyzed using PXRD, small-angle X-ray scattering......In situ synchrotron powder X-ray diffraction (PXRD) measurements have been conducted to follow the nucleation and growth of crystalline CexZr1-xO2 nanoparticles synthesized in supercritical water with a full substitution variation (x = 0, 0.2, 0.5, 0.8, and 1.0). Direction-dependent growth curves...... are determined and described using reaction kinetic models. A distinct change in growth kinetics is observed with increasing cerium content. For x = 0.8 and 1.0 (high cerium content), the growth is initially limited by the surface reaction kinetics; however, at a size of ∼6 nm, the growth changes and becomes...

Crystalline phase-dependent eco-toxicity of titania nanoparticles to freshwater biofilms

International Nuclear Information System (INIS)

Li, Kun; Qian, Jin; Wang, Peifang; Wang, Chao; Liu, Jingjing; Tian, Xin; Lu, Bianhe; Shen, Mengmeng

2017-01-01

The potential toxic impacts of different crystal phases of titania nanoparticles (TNPs) on freshwater biofilms, especially under ultraviolet C irradiation (UVC), are unknown. Here, adverse impacts of three phases (anatase, rutile, and P25, 50 mg L −1 respectively) with UVC irradiation (An-UV, Ru-UV, and P25-UV) on freshwater biofilms were conducted. Characterization experiments revealed that rutile TNPs had a higher water environment stability than anatase and P25 TNPs, possessing a stronger photocatalytic activity under UVC irradiation. Phase-dependent inhibition of cell viability and significant decreases of four- and five-fold in algal biomass at 12 h of exposure were observed compared with unexposed biofilms. Moreover, phase-dependent oxidative stress resulted in remarkably significant reductions (P < 0.01) of the photosynthetic yields of the biofilms, to 40.32% (P25-UV), 48.39% (An-UV), and 46.77% (Ru-UV) of the plateau value obtained in the unexposed biofilms. A shift in community composition that manifested as a strong reduction in diatoms, indicating cyanobacteria and green algae were more tolerant than diatoms when exposed to TNPs. In terms of the toxic mechanisms, rutile TNPs resulted in apoptosis by inducing excessive intracellular reactive oxygen species (ROS) production, whereas P25 and anatase TNPs tended to catalyze enormous acellular ROS lead to cell necrosis under UVC irradiation. - Highlights: • Phase-dependent response of freshwater biofilms to three TNPs was studied with UVC. • Rutile is more stable yet P25 and anatase own better photooxidation level in water. • Decrease in Chl-a and φM and a shift in algae bio-cenosis were phase-dependent. • Phase-dependent stress induced cellular or acellular ROS to reduce cells viability. • Rutile tend to induced apoptosis yet P25 and anatase prefer to cause cell necrosis. - Crystalline-dependent eco-toxicity of TNPs to freshwater biofilms show allotrope of nanoparticles must be considered

Plant-scale anodic dissolution of unirradiated N-Reactor fuel

International Nuclear Information System (INIS)

Gay, E.C.; Miller, W.E.; Laidler, J.J.

1995-01-01

Anodic dissolution tests were made with unirradiated N-Reactor fuel to determine the fuel segment length, diameter, and shape required for high throughput electrorefiner treatment for ultimate disposal in a geologic repository. Based on these tests, a conceptual design was produced of an electrorefiner for a full-scale plant to process N-Reactor spent fuel. In this design, the diameter of an electrode assembly is about 0.6 m (25 in.). Eight of these assemblies in an electrorefiner would accommodate a 1.333-metric-ton batch of N-Reactor fuel. Electrorefining would proceed at a rate of 40 kg uranium per hour

γ-Irradiation assisted synthesis of graphene oxide sheets supported Ag nanoparticles with single crystalline structure and parabolic distribution from interlamellar limitation

Science.gov (United States)

Yue, Yunhao; Zhou, Baoming; Shi, Jie; Chen, Cheng; Li, Nan; Xu, Zhiwei; Liu, Liangsen; Kuang, Liyun; Ma, Meijun; Fu, Hongjun

2017-05-01

This paper reported a method to fabricate graphene oxide sheets supported Ag nanoparticles (AgNPs/GOS) with single crystalline structure and parabolic distribution without surfactant or functional agent. We used imidazole silver nitrate as intercalation precursor into the layers of graphite oxide, and subsequently reduction and growth of interlamellar AgNPs were induced via γ-irradiation. The results illustrated that the synergism of interlamellar limitation of graphite oxide and fragmentation ability of γ-irradiation could prevent coalescent reaction of AgNPs with other oligomeric clusters, and the single crystalline and small-sized (below 13.9 nm) AgNPs were prepared. Moreover, the content and size of AgNPs exhibited parabolic distribution on GOS surface because the graphite oxide exfoliated to GOS from the edge to the central area of layers. In addition, complete exfoliation degree of GOS and large-sized AgNPs were obtained simultaneously under suitable silver ions concentration. Optimized composites exhibited outstanding surface-enhanced Raman scattering properties for crystal violet with enhancement factor of 1.3 × 106 and detection limit of 1.0 × 10-7 M, indicating that the AgNPs/GOS composites could be applied to trace detection of organic dyes molecules. Therefore, this study presented a strategy for developing GOS supported nanometal with single crystalline structure and parabolic distribution based on γ-irradiation.

Photodynamic therapy using upconversion nanoparticles prepared by laser ablation in liquid

Energy Technology Data Exchange (ETDEWEB)

Ikehata, Tomohiro; Onodera, Yuji; Nunokawa, Takashi [Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8502 (Japan); Hirano, Tomohisa; Ogura, Shun-ichiro; Kamachi, Toshiaki [Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8502 (Japan); Odawara, Osamu [Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8502 (Japan); Wada, Hiroyuki, E-mail: wada.h.ac@m.titech.ac.jp [Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8502 (Japan)

2015-09-01

Highlights: • Highly crystalline upconversion nanoparticles were prepared by laser ablation in liquid. • Highly transparent near-IR irradiation generated singlet oxygen. • Viability of cancer cells was significantly decreased by near-IR irradiation. - Abstract: Upconversion nanoparticles were prepared by laser ablation in liquid, and the potential use of the nanoparticles for cancer treatment was investigated. A Nd:YAG/SHG laser (532 nm, 13 ns, 10 Hz) was used for ablation, and the cancer treatment studied was photodynamic therapy (PDT). Morphology and crystallinity of prepared nanoparticles were examined by transmission electron microscopy and X-ray diffraction. Red and green emissions resulting from near-infrared excitation were observed by a fluorescence spectrophotometer. Generation of singlet oxygen was confirmed by a photochemical method using 1,3-diphenylisobenzofuran (DPBF). In vitro experiments using cultivated cancer cells were conducted to investigate PDT effects. Uptake of the photosensitizer by cancer cells and cytotoxicities of cancer cells were also examined. We conclude that the combination of PDT and highly crystalline nanoparticles, which were prepared by laser ablation in liquid, is an effective cancer treatment.

Dissolution experiments of unirradiated uranium dioxide pellets

International Nuclear Information System (INIS)

Ollila, K.

1985-01-01

The purpose of this study was to measure the dissolution rate of uranium from unirradiated uranium dioxide pellets in deionized water and natural groundwater. Moreover, the solubility limit of uranium in natural groundwater was measured. Two different temperatures, 25 and 60 deg C were used. The low oxygen content of deep groundwater was simulated. The dissolution rate of uranium varied from 10 -7 to 10 -8 g cm -2 d -1 . The rate in reionized water was one order of magnitude lower than in groundwater. No great difference was observed between the natural groundwaters with different composition. Temperature seems to have effect on the dissolution rate. The solubility limit of uranium in natural groundwater in reducing conditions, at 25 deg C, varied from 20 to 600 μg/l and in oxidizing conditions, at 60 deg C, from 4 to 17 mg/l

The dissolution of unirradiated UO2 fuel pellets under simulated disposal conditions

International Nuclear Information System (INIS)

Ollila, K.; Leino-Forsman, H.

1993-03-01

The dissolution behaviour of unirradiated UO 2 pellets was studied as a function of water composition under oxidizing and reducing conditions at 25 deg C. The waters included deionized water as the reference water, sodium bicarbonate solutions with varying bicarbonate content, and two different synthetic groundwaters. The release of uranium was measured during static batch dissolution experiments of long duration (3-4 years)

Effect of zinc oxide nanoparticles synthesized by a precipitation

Indian Academy of Sciences (India)

ZnO nanoparticles were synthesized by a precipitation method in aqueous media from zinc nitrate hexahydrate and sodium hydroxide. The synthesized ZnO nanoparticles exhibited a crystalline structure with hexagonal structure of the wurtzite. The morphology of the synthesized ZnO nanoparticles presented a spherical ...

Recording-media-related morphology and magnetic properties of crystalline CoPt{sub 3} and CoPt{sub 3}-Au core-shell nanoparticles synthesized via reverse microemulsion

Energy Technology Data Exchange (ETDEWEB)

Bahmanrokh, Ghazaleh, E-mail: ghazalehbahmanrokh@yahoo.com; Hashim, Mansor; Matori, Khamirul Amin; Kanagesan, Samikannu; Sabbaghizadeh, Rahim; Ezzad Shafie, Mohd Shamsul [Materials Synthesis and Characterization Laboratory, Institute of Advanced Technology, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Navasery, Manizheh; Soltani, Nayereh [Department of Physics, Faculty of Science, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor (Malaysia); Vaziri, Parisa [Department of Medical Physics and Biomedical Engineering, Shahid Beheshti University of Medical Sciences, Tehran (Iran, Islamic Republic of)

2014-09-07

A comparative experimental study of the magnetic properties of CoPt{sub 3} and CoPt{sub 3}/Au nanoparticles as well as a detailed study of the structural properties of the samples by X-ray diffraction, Transmission electron microscopy, and vibrating sample magnetometer is presented in this work. In addition, the effect of particle size on the structure and magnetic properties of nanoparticles prepared by microemulsion is studied. The correlation between particle size, crystallinity, and magnetization was studied as well. CoPt nanoparticles have been studied intensively over the last decade because of their increased magnetic anisotropy in the ordered phase that can be interesting for high density magnetic recording. A significant high coercivity for as-prepared CoPt{sub 3} and CoPt{sub 3}-Au nanoparticles was obtained at room temperature and enhanced after annealing. The focused aim of our study is to obtain high coercivity at room temperature that follows the Curie-Weiss law. This indicates an interacting system in which the nanoparticles behave like single domain ferromagnetic materials in the particle size range of 8 to 35 nm. In addition, the interaction increases by cooling the samples to low temperature around 15 K. Temperature dependence 1/M graph was obtained to investigate the behavior of nanoparticles at low temperature and shows the best fit with Curie-Weis mode.

Vapor-phase synthesis and characterization of ZnSe nanoparticles

Science.gov (United States)

Sarigiannis, D.; Pawlowski, R. P.; Peck, J. D.; Mountziaris, T. J.; Kioseoglou, G.; Petrou, A.

2002-06-01

Compound semiconductor nanoparticles are an exciting class of materials whose unique optical and electronic properties can be exploited in a variety of applications, including optoelectronics, photovoltaics, and biophotonics. The most common route for synthesizing such nanoparticles has been via liquid-phase chemistry in reverse micelles. This paper discusses a flexible vapor-phase technique for synthesis of crystalline compound semiconductor nanoparticles using gas-phase condensation reactions near the stagnation point of a counterflow jet reactor. ZnSe nanoparticles were formed by reacting vapors of dimethylzinc: triethylamine adduct and hydrogen selenide at 120Torr and room temperature (28°C). No attempt was made to passivate the surface of the particles, which were collected as random aggregates on silicon wafers or TEM grids placed downstream of the reaction zone. Particle characterization using TEM, electron diffraction, Raman and EDAX revealed that the aggregates consisted of polycrystalline ZnSe nanoparticles, almost monodisperse in size (with diameters of ~40nm). The polycrystalline nanoparticles appear to have been formed by coagulation of smaller single-crystalline nanoparticles with characteristic size of 3-5 run.

Plant-scale anodic dissolution of unirradiated N-Reactor fuel

International Nuclear Information System (INIS)

Gay, E.C.; Miller, W.E.; Laidler, J.J.

1995-01-01

Anodic dissolution tests were made with unirradiated N-Reactor fuel to determine the fuel segment length, diameter, and shape required for high throughput electro-refiner treatment for ultimate disposal in a geologic repository. Based on these tests, a conceptual design was produced of an electro-refiner for a full-scale plant to process N-Reactor spent fuel. In this design, the diameter of an electrode assembly is about 0.6 m (25 in.). Eight of these assemblies in an electro-refiner would accommodate a 1.333-metric-ton batch of N-Reactor fuel. Electrorefining would proceed at a rate of 40 kg uranium per hour. (author)

Supercooled smectic nanoparticles

DEFF Research Database (Denmark)

Kuntsche, Judith; Westesen, K; Drechsler, M

2004-01-01

The possibility of preparing nanoparticles in the supercooled thermotropic liquid crystalline state from cholesterol esters with saturated acyl chains as well as the incorporation of model drugs into the dispersions was investigated using cholesteryl myristate (CM) as a model cholesterol ester....

Lipid-Based Liquid Crystalline Nanoparticles Facilitate Cytosolic Delivery of siRNA via Structural Transformation.

Science.gov (United States)

He, Shufang; Fan, Weiwei; Wu, Na; Zhu, Jingjing; Miao, Yunqiu; Miao, Xiaran; Li, Feifei; Zhang, Xinxin; Gan, Yong

2018-04-11

RNA interference (RNAi) technology has shown great promise for the treatment of cancer and other genetic disorders. Despite the efforts to increase the target tissue distribution, the safe and effective delivery of siRNA to the diseased cells with sufficient cytosolic transport is another critical factor for successful RNAi clinical application. Here, the constructed lipid-based liquid crystalline nanoparticles, called nano-Transformers, can transform thestructure in the intracellular acidic environment and perform high-efficient siRNA delivery for cancer treatment. The developed nano-Transformers have satisfactory siRNA loading efficiency and low cytotoxicity. Different from the traditional cationic nanocarriers, the endosomal membrane fusion induced by the conformational transition of lipids contributes to the easy dissociation of siRNA from nanocarriers and direct release of free siRNA into cytoplasm. We show that transfection with cyclin-dependent kinase 1 (CDK1)-siRNA-loaded nano-Transformers causes up to 95% reduction of relevant mRNA in vitro and greatly inhibits the tumor growth without causing any immunogenic response in vivo. This work highlights that the lipid-based nano-Transformers may become the next generation of siRNA delivery system with higher efficacy and improved safety profiles.

Enhanced antitumor efficacy and counterfeited cardiotoxicity of combinatorial oral therapy using Doxorubicin- and Coenzyme Q10-liquid crystalline nanoparticles in comparison with intravenous Adriamycin

DEFF Research Database (Denmark)

Swarnakar, Nitin K; Thanki, Kaushik; Jain, Sanyog

2014-01-01

and strong synergism for combination at 1:10 dose ratio owing to higher cellular uptake, nuclear colocalization, higher apoptotic index and 8-OHdG levels. The prophylactic antitumor efficacy of the CoQ10-LCNPs was also established using tumor induction and progression studies. Finally, therapeutic antitumor......, with Dox-induced-cardiotoxicity was completely counterfeited in combination. In nutshell, LCNPs pose great potential in improving the therapeutic efficacy of drugs by oral route of administration. FROM THE CLINICAL EDITOR: This study describes the use of liquid crystalline nanoparticles containing coenzyme...

Revised ANL-reported tensile data for unirradiated and irradiated (FFTF, HFIR) V-Ti and V-Cr-Ti alloys

International Nuclear Information System (INIS)

Billone, M.C.

1998-01-01

The tensile data for all unirradiated and irradiated vanadium alloys samples tested at Argonne National Laboratory (ANL) have been critically reviewed and, when necessary, revised. The review and revision are based on reanalyzing the original load-displacement strip chart recordings by a methodology consistent with current ASTM standards. For unirradiated alloys (162 samples), the revised values differ from the previous values as follows: -11±19 MPa (-4±6%) for yield strength (YS), -3±15 MPa (-1±3%) for ultimate tensile strength (UTS), -5±2% strain for uniform elongation (UE), and -4±2% strain for total elongation (TE). Of these changes, the decrease in -1±6 MPa (0±1%) for UTS, -5±2% for UE, and -4±2% for TE. Of these changes, the decrease in UE values for alloys irradiated and tested at 400--435 C is the most significant. This decrease results from the proper subtraction of nongauge-length deformation from measured crosshead deformation. In previous analysis of the tensile curves, the nongauge-length deformation was not correctly determined and subtracted from the crosshead displacement. The previously reported and revised tensile values for unirradiated alloys (20--700 C) are tabulated in Appendix A. The revised tensile values for the FFTF-irradiated (400--600 C) and HFIR-irradiated (400 C) alloys are tabulated in Appendix B, along with the neutron damage and helium levels. Appendix C compares the revised values to the previously reported values for irradiated alloys. Appendix D contains previous and revised values for the tensile properties of unirradiated V-5Cr-5Ti (BL-63) alloy exposed to oxygen

Synthesis of Titanium Dioxide nanoparticles via sucrose ester micelle-mediated hydrothermal processing route

International Nuclear Information System (INIS)

Anwar, N.S.; Kassim, A.; Lim, H.N.; Zakarya, S.A.; Huang, N.M.

2010-01-01

Titanium dioxide nanoparticles were synthesized via low-temperature sucrose ester micelle-mediated hydrothermal processing route using titanium isopropoxide as the precursor. X-ray diffractometer revealed that the samples possessed a mixed crystalline phases consisting of anatase and brookite in which anatase was the main phase. Upon increasing the hydrothermal reaction temperature, the degree of crystallinity of the nanoparticles improved and their morphology transformed from bundles of needles to rods and to spheres. Photo catalytic behaviour of the as-synthesized nanoparticles was investigated by photodegradation of methylene blue solution in an ultraviolet A irradiating photo reactor. The as-synthesized nanoparticles exhibited higher photo catalytic performance as compared to the commercial counterpart. (author)

Electro-purification of carbon nanotube networks without damaging the assembly structure and crystallinity

Science.gov (United States)

Yang, Xueqin; Yang, Ming; Zhang, Huichao; Zhao, Jingna; Zhang, Xiaohua; Li, Qingwen

2018-06-01

Fe-containing nanoparticles are of a high mass fraction in the as-grown carbon nanotube (CNT) network. By controlling the S-to-Fe atom ratio in the growth feedstock and introducing water as a weak oxidant, highly crystalline few-walled CNT network can be obtained, with a mass fraction of over 20 wt% for the Fe-containing nanoparticles. We report here an electron-oxidation-based purification method to efficiently remove the Fe-containing nanoparticles without inducing clear damage to either the assembly structure or the tube crystallinity. The purification could increase the ratio between Raman D and G peak intensities slightly from 0.08 to 0.12, decrease the specific conductivity from 0.31 to 0.24 S m2/g and the Fe content from >20 wt% to ≈1 wt%, and modify the capacitance just by about 13 F/g. All these indicate that the CNT network was well maintained by such gentle electro-oxidation-based purification. In addition, the purified CNT network can exhibit advantages in mechanical and electrical applications.

Synthesis and characterization of cobalt/gold bimetallic nanoparticles

International Nuclear Information System (INIS)

Cheng, Guangjun; Hight Walker, Angela R.

2007-01-01

Cobalt/gold (Co/Au) bimetallic nanoparticles are prepared by chemically reducing gold (III) chloride to gold in the presence of pre-synthesized Co nanoparticles. Transmission electron microscopy (TEM), ultraviolet-visible (UV-vis) absorption spectrometry, and a superconducting quantum interference device (SQUID) magnetometer have been used to characterize as-prepared bimetallic nanoparticles. Our findings demonstrate Au not only grows onto Co nanoparticles, forming a surface coating, but also diffuses into Co nanoparticles. The introduction of Au alters the crystalline structure of Co nanoparticles and changes their magnetic properties. Dodecanethiols induce a reorganization of as-prepared Co/Au bimetallic nanoparticles

Antimicrobial effects of zinc oxide nanoparticles modified with silver

International Nuclear Information System (INIS)

Lopes, Rayssa Souza; Arantes, Tatiane Moraes

2016-01-01

Full text: With the emergence of resistant microbial organisms to multiple antibiotics, different shapes of silver nanoparticles are among the most promising antimicrobial agents that have been developed from nanotechnology. Besides the silver nanoparticles oxide nanoparticles such as zinc oxide (ZnO) is gaining prominence due to its bactericidal properties. [1-3]. Thus, this study aims to develop biomaterials from zinc oxide nanoparticles modified with silver with antimicrobial properties. The ZnO nanoparticles were synthesized by hydrothermal processing by alkaline hydrolysis zinc acetate. Colloidal dispersions of silver nanoparticles were synthesized by the Turkevich method using sodium citrate to reduce silver nitrate at high pH and at 90 °C in the presence of zinc oxide nanoparticles. Both nanoparticles were characterized by X-ray diffraction (XRD), FTIR and Raman spectroscopy and scanning electron microscopy (SEM). The XRD and Raman spectra showed crystalline ZnO colloidal nanoparticles were obtained in the hexagonal phase. XRD measure showed cubic silver diffraction peaks cubic phase confirmed the presence of the silver nanoparticles decorated zinc oxide nanoparticles. SEM images showed ZnO nanoparticles presented a nanorod shapes with length around 80 nm decorated with spherical silver nanoparticles about 20 nm in diameter The results showed that crystalline zinc oxide colloidal nanoparticles with rod-like morphology and uniform decorated with silver spherical nanoparticles size were obtained by hydrothermal synthesis. Results of antibacterial tests indicate that the ZnO/Ag nanoparticles have antibacterial properties against both Staphylococcus aureus and Escherichia coli. The results demonstrated that the ZnO/Ag nanoparticles have potential use as biomaterials in medical/odontological applications. (author)

Antimicrobial effects of zinc oxide nanoparticles modified with silver

Energy Technology Data Exchange (ETDEWEB)

Lopes, Rayssa Souza; Arantes, Tatiane Moraes, E-mail: rayssasouza.net@gmail.com [Universidade Federal de Goias (UFG), Goiania (Brazil)

2016-07-01

Full text: With the emergence of resistant microbial organisms to multiple antibiotics, different shapes of silver nanoparticles are among the most promising antimicrobial agents that have been developed from nanotechnology. Besides the silver nanoparticles oxide nanoparticles such as zinc oxide (ZnO) is gaining prominence due to its bactericidal properties. [1-3]. Thus, this study aims to develop biomaterials from zinc oxide nanoparticles modified with silver with antimicrobial properties. The ZnO nanoparticles were synthesized by hydrothermal processing by alkaline hydrolysis zinc acetate. Colloidal dispersions of silver nanoparticles were synthesized by the Turkevich method using sodium citrate to reduce silver nitrate at high pH and at 90 °C in the presence of zinc oxide nanoparticles. Both nanoparticles were characterized by X-ray diffraction (XRD), FTIR and Raman spectroscopy and scanning electron microscopy (SEM). The XRD and Raman spectra showed crystalline ZnO colloidal nanoparticles were obtained in the hexagonal phase. XRD measure showed cubic silver diffraction peaks cubic phase confirmed the presence of the silver nanoparticles decorated zinc oxide nanoparticles. SEM images showed ZnO nanoparticles presented a nanorod shapes with length around 80 nm decorated with spherical silver nanoparticles about 20 nm in diameter The results showed that crystalline zinc oxide colloidal nanoparticles with rod-like morphology and uniform decorated with silver spherical nanoparticles size were obtained by hydrothermal synthesis. Results of antibacterial tests indicate that the ZnO/Ag nanoparticles have antibacterial properties against both Staphylococcus aureus and Escherichia coli. The results demonstrated that the ZnO/Ag nanoparticles have potential use as biomaterials in medical/odontological applications. (author)

Growth and Brilliant Photo-Emission of Crystalline Hexagonal Column of Alq3 Microwires

Directory of Open Access Journals (Sweden)

Seokho Kim

2018-03-01

Full Text Available We report the growth and nanoscale luminescence characteristics of 8-hydroxyquinolinato aluminum (Alq3 with a crystalline hexagonal column morphology. Pristine Alq3 nanoparticles (NPs were prepared using a conventional reprecipitation method. Crystal hexagonal columns of Alq3 were grown by using a surfactant-assisted self-assembly technique as an adjunct to the aforementioned reprecipitation method. The formation and structural properties of the crystalline and non-crystalline Alq3 NPs were analyzed with scanning electron microscopy and X-ray diffraction. The nanoscale photoluminescence (PL characteristics and the luminescence color of the Alq3 single NPs and their crystal microwires (MWs were evaluated from color charge-coupled device images acquired using a high-resolution laser confocal microscope. In comparison with the Alq3 NPs, the crystalline MWs exhibited a very bright and sharp emission. This enhanced and sharp emission from the crystalline Alq3 single MWs originated from effective π-π stacking of the Alq3 molecules due to strong interactions in the crystalline structure.

Comparison of the growth of Listeria monocytogenes in unirradiated and irradiated cook-chill roast beef and gravy at refrigeration temperatures

International Nuclear Information System (INIS)

Grant, I.R.; Nixon, C.R.; Patterson, M.F.

1993-01-01

Specific growth rates of two strains of Listeria monocytogenes in unirradiated and irradiated (2 kGy) roast beef and gravy stored at 5° and 10°C were found to be similar. However, exponential growth of L. monocytogenes after irradiation was preceded by an extended lag period of 6–9 d at 5°C and 3–4 d at 10°C, compared with lag periods of 1–2 d and <0.1 d in unirradiated beef and gravy stored similarly

Facile solid-state synthesis of oxidation-resistant metal nanoparticles at ambient conditions

Science.gov (United States)

Lee, Kyu Hyung; Jung, Hyuk Joon; Lee, Ju Hee; Kim, Kyungtae; Lee, Byeongno; Nam, Dohyun; Kim, Chung Man; Jung, Myung-Hwa; Hur, Nam Hwi

2018-05-01

A simple and scalable method for the synthesis of metal nanoparticles in the solid-state was developed, which can produce nanoparticles in the absence of solvents. Nanoparticles of coinage metals were synthesized by grinding solid hydrazine and the metal precursors in their acetates and oxides at 25 °C. The silver and gold acetates converted completely within 6 min into Ag and Au nanoparticles, respectively, while complete conversion of the copper acetate to the Cu sub-micrometer particles took about 2 h. Metal oxide precursors were also converted into metal nanoparticles by grinding alone. The resulting particles exhibit distinctive crystalline lattice fringes, indicating the formation of highly crystalline phases. The Cu sub-micrometer particles are better resistant to oxidation and exhibit higher conductivity compared to conventional Cu nanoparticles. This solid-state method was also applied for the synthesis of platinum group metals and intermetallic Cu3Au, which can be further extended to synthesize other metal nanoparticles.

Constructing MnO{sub 2}/single crystalline ZnO nanorod hybrids with enhanced photocatalytic and antibacterial activity

Energy Technology Data Exchange (ETDEWEB)

Yu, Weiwei [College of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410114 (China); Liu, Tiangui, E-mail: tianguiliu@gmail.com [College of Physics and Microelectronics Science, Hunan University, Changsha 410082 (China); Cao, Shiyi; Wang, Chen [College of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410114 (China); Chen, Chuansheng, E-mail: 1666423158@qq.com [College of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410114 (China)

2016-07-15

In order to improve the photocatalytic and antibacterial activity of ZnO nanorods, ZnO nanorods decorated with MnO{sub 2} nanoparticles (MnO{sub 2}/ZnO nanorod hybrids) were prepared by using microwave assisted coprecipitation method under the influence of hydrogen peroxide, and the structure, photocatalytic activity and antibacterial property of the products were studied. Experimental results indicated that MnO{sub 2} nanoparticles are decorated on the surface of single crystalline ZnO nanorods. Moreover, the resultant MnO{sub 2}/ZnO nanorod hybrids have been proven to possess good photocatalytic and antibacterial activity, which their degradated efficiency for Rhodamin B (RhB) is twice as the pure ZnO nanorods. Enhancement for photocatalytic and antibacterial activity is mainly attributed to the low band gap energy and excellent electrochemical properties of MnO{sub 2} nanoparticles. - Graphical abstract: The MnO{sub 2}/single crystalline ZnO nanorods hybrids, which MnO{sub 2} nanoparticles are loaded on the surface of ZnO nanorods, were prepared by the step-by-step precipitation method under the assistance of ammonia and hydrogen peroxide. Display Omitted - Highlights: • MnO{sub 2}/ZnO nanorod hybrids were prepared by the step-by-step assembly method. • Single crystalline ZnO nanorods can be decorated by MnO{sub 2} nanoparticles. • MnO{sub 2}/ZnO nanorod hybrids possess good photocatalytic and antibacterial activity. • MnO{sub 2} can improve the photocatalytic activity of ZnO nanorods under visible light.

Repairing Nanoparticle Surface Defects

NARCIS (Netherlands)

Marino, Emanuele; Kodger, Thomas E.; Crisp, R.W.; Timmerman, Dolf; MacArthur, Katherine E.; Heggen, Marc; Schall, Peter

2017-01-01

Solar devices based on semiconductor nanoparticles require the use of conductive ligands; however, replacing the native, insulating ligands with conductive metal chalcogenide complexes introduces structural defects within the crystalline nanostructure that act as traps for charge carriers. We

Stabilized amorphous glibenclamide nanoparticles by high-gravity technique

International Nuclear Information System (INIS)

Yu Lei; Li Caixia; Le Yuan; Chen Jianfeng; Zou Haikui

2011-01-01

Highlights: · Amorphous glibenclamide nanoparticles of 220 nm are obtained using the high-gravity technique. · The dissolution rate of these nanoparticles achieves 85% in 5 min, while those of the raw glibenclamide and the commercial glibenclamide tablet only reach 35% and 55% respectively during the same period. · The morphology, particle size, crystalline form and dissolution rate of these nanoparticles almost remain constant after keeping more than 70 days. - Abstract: The stable amorphous glibenclamide nanoparticles was obtained via anti-solvent precipitation using the high-gravity technique in this study. The effects of operating variables on the particle size were investigated. The properties of glibenclamide nanoparticles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC) and dissolution test. The prepared glibenclamide nanoparticles had a mean size of 220 nm within a narrow distribution. The dissolution rate of glibenclamide nanoparticles was obviously faster than that of the raw glibenclamide or the commercial glibenclamide tablet. It achieved 85% in 5 min, while those of the raw glibenclamide and the commercial glibenclamide tablet achieved 35% and 55% respectively during the same period. The physical stability of the nanoparticles was tested after storing for more than 70 days at room conditions. Their morphology, particle size, crystalline form and dissolution rate almost remained constant during storage.

ZnO doped SnO2 nanoparticles heterojunction photo-catalyst for environmental remediation

International Nuclear Information System (INIS)

Lamba, Randeep; Umar, Ahmad; Mehta, S.K.; Kansal, Sushil Kumar

2015-01-01

ZnO doped SnO 2 nanoparticles were synthesized by facile and simple hydrothermal technique and used as an effective photocatalyst for the photocatalytic degradation of harmful and toxic organic dye. The prepared nanoparticles were characterized in detail using different techniques for morphological, structural and optical properties. The characterization results revealed that the synthesized nanoparticles possess both crystal phases of tetragonal rutile phase of pure SnO 2 and wurtzite hexagonal phase of ZnO. In addition, the nanoparticles were synthesized in very high quantity with good crystallinity. The photocatalytic activity of prepared nanoparticles was evaluated by the photocatalytic degradation of methylene blue (MB) dye. Detailed photocatalytic experiments based on the effects of irradiation time, catalyst dose and pH were performed and presented in this paper. The detailed photocatalytic experiments revealed that the synthesized ZnO doped SnO 2 nanoparticles heterojunction photocatalyst exhibit best photocatalytic performance when the catalyst dose was 0.25 g/L and pH = 10. ZnO doped SnO 2 nanoparticles heterojunction photocatalyst was also compared with commercially available TiO 2 (PC-50), TiO 2 (PC-500) and SnO 2 and interestingly ZnO doped SnO 2 nanoparticles exhibited superior photocatalytic performance. The presented work demonstrates that the prepared ZnO doped SnO 2 nanoparticles are promising material for the photocatalytic degradation of organic dyes and toxic chemicals. - Highlights: • Synthesis of well-crystalline ZnO-doped SnO 2 nanoparticles. • Excellent morphological, crystalline and photoluminescent properties. • Efficient environmental remediation using ZnO-doped SnO 2 nanoparticles.

A review of the rates of reaction of unirradiated uranium in gaseous atmospheres

International Nuclear Information System (INIS)

Pearce, R.J.

1989-10-01

The review collates available quantitative rate data for the reaction of unirradiated uranium in dry and moist air, steam and carbon dioxide based atmospheres at temperatures ranging from room temperature to above the melting point of uranium. Reactions in nitrogen and carbon monoxide are also considered. The aim of the review is to provide a compilation of base data for the hazard analysis of fault conditions relating to Magnox fuel. (author)

Preparation and characterization of polymeric nanoparticles from Gadong starch

Energy Technology Data Exchange (ETDEWEB)

Sisika, Regina; Ahmad, Wan Yaacob Wan; Lazim, Azwan Mat [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia 43600 Bangi, Selangor (Malaysia); Fazry, Shazrul [School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia 43600 Bangi, Selangor (Malaysia)

2015-09-25

Dioscorea hispida (Gadong tuber) was seldom used and forgotten as a food source due to their toxicity. In contrast to that, the Gadong tuber can be a source of polysaccharides which can be manipulated as an alternative source for industrial applications. This research reported on how to synthesize starch nanoparticles from Gadong tuber by using a simple acid hydrolysis process. The yield of starch nanoparticles obtained from seven days of acid hydrolysis was reduced to 13%. The X-ray diffraction measurements showed that the native Gadong starch particle is of the C-crystalline type, and that the synthesized nanoparticles showed an increase in crystallinity compared to the native particles. Transmission electron microscopy results demonstrated that the starch particle morphologies were either round or irregular shape, with diameters ranging from 96-110 nm.

Preparation and characterization of polymeric nanoparticles from Gadong starch

Science.gov (United States)

Sisika, Regina; Ahmad, Wan Yaacob Wan; Fazry, Shazrul; Lazim, Azwan Mat

2015-09-01

Dioscorea hispida (Gadong tuber) was seldom used and forgotten as a food source due to their toxicity. In contrast to that, the Gadong tuber can be a source of polysaccharides which can be manipulated as an alternative source for industrial applications. This research reported on how to synthesize starch nanoparticles from Gadong tuber by using a simple acid hydrolysis process. The yield of starch nanoparticles obtained from seven days of acid hydrolysis was reduced to 13%. The X-ray diffraction measurements showed that the native Gadong starch particle is of the C-crystalline type, and that the synthesized nanoparticles showed an increase in crystallinity compared to the native particles. Transmission electron microscopy results demonstrated that the starch particle morphologies were either round or irregular shape, with diameters ranging from 96-110 nm.

Preparation and characterization of polymeric nanoparticles from Gadong starch

International Nuclear Information System (INIS)

Sisika, Regina; Ahmad, Wan Yaacob Wan; Lazim, Azwan Mat; Fazry, Shazrul

2015-01-01

Dioscorea hispida (Gadong tuber) was seldom used and forgotten as a food source due to their toxicity. In contrast to that, the Gadong tuber can be a source of polysaccharides which can be manipulated as an alternative source for industrial applications. This research reported on how to synthesize starch nanoparticles from Gadong tuber by using a simple acid hydrolysis process. The yield of starch nanoparticles obtained from seven days of acid hydrolysis was reduced to 13%. The X-ray diffraction measurements showed that the native Gadong starch particle is of the C-crystalline type, and that the synthesized nanoparticles showed an increase in crystallinity compared to the native particles. Transmission electron microscopy results demonstrated that the starch particle morphologies were either round or irregular shape, with diameters ranging from 96-110 nm

Green synthesis of silver nanoparticles using tannins

Science.gov (United States)

Raja, Pandian Bothi; Rahim, Afidah Abdul; Qureshi, Ahmad Kaleem; Awang, Khalijah

2014-09-01

Colloidal silver nanoparticles were prepared by rapid green synthesis using different tannin sources as reducing agent viz. chestnut (CN), mangrove (MG) and quebracho (QB). The aqueous silver ions when exposed to CN, MG and QB tannins were reduced which resulted in formation of silver nanoparticles. The resultant silver nanoparticles were characterized using UV-Visible, X-ray diffraction (XRD), scanning electron microscopy (SEM/EDX), and transmission electron microscopy (TEM) techniques. Furthermore, the possible mechanism of nanoparticles synthesis was also derived using FT-IR analysis. Spectroscopy analysis revealed that the synthesized nanoparticles were within 30 to 75 nm in size, while XRD results showed that nanoparticles formed were crystalline with face centered cubic geometry.

A systematic study of the controlled generation of crystalline iron oxide nanoparticles on graphene using a chemical etching process

Directory of Open Access Journals (Sweden)

Peter Krauß

2017-09-01

Full Text Available Chemical vapor deposition (CVD of carbon precursors employing a metal catalyst is a well-established method for synthesizing high-quality single-layer graphene. Yet the main challenge of the CVD process is the required transfer of a graphene layer from the substrate surface onto a chosen target substrate. This process is delicate and can severely degrade the quality of the transferred graphene. The protective polymer coatings typically used generate residues and contamination on the ultrathin graphene layer. In this work, we have developed a graphene transfer process which works without a coating and allows the transfer of graphene onto arbitrary substrates without the need for any additional post-processing. During the course of our transfer studies, we found that the etching process that is usually employed can lead to contamination of the graphene layer with the Faradaic etchant component FeCl3, resulting in the deposition of iron oxide FexOy nanoparticles on the graphene surface. We systematically analyzed the removal of the copper substrate layer and verified that crystalline iron oxide nanoparticles could be generated in controllable density on the graphene surface when this process is optimized. It was further confirmed that the FexOy particles on graphene are active in the catalytic growth of carbon nanotubes when employing a water-assisted CVD process.

Role of the crystalline form of titanium dioxide nanoparticles: Rutile, and not anatase, induces toxic effects in Balb/3T3 mouse fibroblasts.

Science.gov (United States)

Uboldi, Chiara; Urbán, Patricia; Gilliland, Douglas; Bajak, Edyta; Valsami-Jones, Eugenia; Ponti, Jessica; Rossi, François

2016-03-01

The wide use of titanium dioxide nanoparticles (TiO2 NPs) in industrial applications requires the investigation of their effects on human health. In this context, we investigated the effects of nanosized and bulk titania in two different crystalline forms (anatase and rutile) in vitro. By colony forming efficiency assay, a dose-dependent reduction of the clonogenic activity of Balb/3T3 mouse fibroblasts was detected in the presence of rutile, but not in the case of anatase NPs. Similarly, the cell transformation assay and the micronucleus test showed that rutile TiO2 NPs were able to induce type-III foci formation in Balb/3T3 cells and appeared to be slightly genotoxic, whereas anatase TiO2 NPs did not induce any significant neoplastic or genotoxic effect. Additionally, we investigated the interaction of TiO2 NPs with Balb/3T3 cells and quantified the in vitro uptake of titania using mass spectrometry. Results showed that the internalization was independent of the crystalline form of TiO2 NPs but size-dependent, as nano-titania were taken up more than their respective bulk materials. In conclusion, we demonstrated that the cytotoxic, neoplastic and genotoxic effects triggered in Balb/3T3 cells by TiO2 NPs depend on the crystalline form of the nanomaterial, whereas the internalization is regulated by the particle size. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

pH induced protein-scaffold biosynthesis of tunable shape gold nanoparticles

International Nuclear Information System (INIS)

Zhang Xiaorong; He Xiaoxiao; Wang Kemin; Ren Fang; Qin Zhihe

2011-01-01

In this paper, a pH-inductive protein-scaffold biosynthesis of shape-tunable crystalline gold nanoparticles at room temperature has been developed. By simple manipulation of the reaction solution's pH, anisotropic gold nanoparticles including spheres, triangles and cubes could be produced by incubating an aqueous solution of sodium tetrachloroaurate with Dolichomitriopsis diversiformis biomasses after immersion in ultrapure Millipore water overnight. A moss protein with molecular weight of about 71 kDa and pI of 4.9 was the primary biomolecule involved in the biosynthesis of gold nanoparticles. The secondary configuration of the proteins by CD spectrum implied that the moss protein could display different secondary configurations including random coil, α-helix and intermediate conformations between random coil and α-helix for the experimental pH solution. The growth process of gold nanoparticles further showed that the moss protein with different configurations provided the template scaffold for the shape-controlled biosynthesis of gold nanoparticles. The constrained shape of the gold nanoparticles, however, disappeared in boiled moss extract. The gold nanoparticles with designed morphology were successfully reconstructed using the moss protein purified from the gold nanoparticles. Structural characterizations by SEM, TEM and SAED showed that the triangular and cubic gold nanoparticles were single crystalline.

Induction of lethal mutations in the x-chromosome of unirradiated Drosophila oocytes after fertilization by irradiated spermatozoa

International Nuclear Information System (INIS)

Shaposhnikov, M.V.; Zainullin, V.G.

2003-01-01

Full text: In primary study on Drosophila it was found that irradiated male X-chromosomes induce recessive lethals in unirradiated female homologues (Abeleva et al., 1961, Radiobiologya. 1:123-126). The same effects were obtained in Drosophila in some recent investigations. The mechanisms of these effects is unknown. However it may be responsible for low-dose radiation effects as it induce mutations in unirradiated DNA. We assume that this effect may be a result of activation of error prone repair in response to preliminary DNA lesions in irradiated chromosome. In this research we analyse the frequencies of the recessive lethal mutations in the X-chromosome of Drosophila females mated with irradiated Basc males. We used acute irradiation with a dose rate of 10 Gy. For testing our hypothesis we use the mus209 and mei-41 mutant females. Mus209 is a PCNA gene homologue and mei-41 is a homologue of ATM gene. These genes are involved in post-replication DNA repair which may be error prone repair in Drosophila. It was obtained the tendency to decreasing the mutation rate at the mei-41[D5] background and decreasing mutation rate in mus209[B1] background in comparison with wild type strains CS (p<0.05). The obtained results demonstrate the possible role of mus209[B1] and mei-41[D5] genes in the inducing of mutations in the unirradiated X-chromosome in the presence of irradiated homologue

Scintillation activity in an unirradiated single crystal of 3-hydroxyxanthine

International Nuclear Information System (INIS)

Cooke, D.W.; Jahan, M.S.; Alexander, C. Jr.

1976-01-01

A method of growing single crystals (approximately 4mm long) of 3-hydroxyxanthine is described. Observed scintillations occurring in an unirradiated single crystal of this potent oncogen as the temperature is lowered from 300 to 90 K are shown. It was found that these scintillations occur upon heating or cooling and do not diminish in activity as the number of heating and cooling cycles increase. It was found that a short duration u.v. exposure would terminate the scintillation activity and various attempts (such as annealing and pressure changes) to rejuvenate them were unsuccessful. With these observations in mind speculation is made concerning the mechanisms associated with the production of purine N-oxide derivatives. (U.K.)

Synthesis, characterization and catalytic activity of silver nanoparticles using Tribulus terrestris leaf extract.

Science.gov (United States)

Ashokkumar, S; Ravi, S; Kathiravan, V; Velmurugan, S

2014-01-01

Biomediated silver nanoparticles were synthesized with the aid of an eco-friendly biomaterial, namely, aqueous Tribulus terrestris extract. Silver nanoparticles were synthesized using a rapid, single step, and completely green biosynthetic method employing aqueous T. terrestris leaf extracts as both the reducing and capping agent. Silver ions were rapidly reduced by aqueous T. terrestris leaf extracts, leading to the formation of highly crystalline silver nanoparticles. An attempt has been made and formation of the silver nanoparticles was verified by surface plasmon spectra using an UV-vis (Ultra violet), spectrophotometer. Morphology and crystalline structure of the prepared silver nanoparticles were characterized by TEM (Transmission Electron Microscope) and XRD (X-ray Diffraction), techniques, respectively. FT-IR (Fourier Transform Infrared), analysis suggests that the obtained silver nanoparticles might be stabilized through the interactions of carboxylic groups, carbonyl groups and the flavonoids present in the T. terrestris extract. Copyright © 2013 Elsevier B.V. All rights reserved.

Thermogravimetric studies of the thermo-oxidative stability of irradiated and unirradiated polyethylene. 2. Combined antioxidants

Energy Technology Data Exchange (ETDEWEB)

Novakovic, L; Gal, O; Markovic, V; Stannett, V T

1985-01-01

In part one of this series the effects of a phenolic, an amine and a thioester antioxidant on the thermo-oxidative stability of irradiated and unirradiated low-density polyethylene was reported. In this paper the effects of combined phenolic and thioester stabilizers are described. Isothermal thermogravimetric analysis was used to study the systems. Pronounced synergism was observed with the induction periods, the time when the initial weight loss begins and the 5% weight loss. At about 50% of each stabilizer increases greater than twofold were observed both with the unirradiated and irradiated polymers. The rate constants for oxygen uptake were decreased. However, the rates of degradation at 5% weight loss fell between the values of the two pure stabilizers with no pronounced synergism in either case. In the absence of oxygen little effect of either antioxidant or their mixtures was observed. The corresponding activation energies were somewhat higher, however, with the irradiated samples containing antioxidants. Dynamic thermogravimetry was used for this study. A kinetic analysis indicated that there were somewhat different modes of degradation at lower- and higher-temperature ranges. (author).

Histochemical differentiation between unirradiated and gamma-irradiated tissue in commercial use of some irradiated vegetables

International Nuclear Information System (INIS)

Foa, E.

1978-01-01

The use of gamma irradiation as a commercial method for the preservation of fruits and vegetables calls for methods of differentiation between unirradiated and irradiated products. A new approach to studying the influence of gamma irradiation on vegetable tissue at the cellular level by histochemical techniques has been developed by the authors and already applied to a number of fruits and vegetables. The possibility of evidencing radiation effects in the polysaccharide components of the cell wall suggested that these detected differences could be applied to differentiate irradiated from unirradiated tomatoes and potatoes. Some work done to determine changes in the cell wall polysaccharides of gamma-irradiated potatoes and tomatoes and to relate these changes to some other factors, such as storage time and vegetable variety, is reported here. While significant differences have been found in the optical densities of the total polysaccharides of the cell wall as a function of irradiation and of the other variables mentioned, it is not yet possible to use these values as a means of reliable differentiation. (author)

Mesophase and size manipulation of itraconazole liquid crystalline nanoparticles produced via quasi nanoemulsion precipitation.

Science.gov (United States)

Mugheirbi, Naila A; Tajber, Lidia

2015-10-01

The fabrication of drug nanoparticles (NPs) with process-mediated tunable properties and performances continues to grow rapidly during the last decades. This study investigates the synthesis and phase tuning of nanoparticulate itraconazole (ITR) mesophases using quasi nanoemulsion precipitation from acetone/water systems to seek out an alternative pathway to the nucleation-based NP formation. ITR liquid crystalline (LC) phases were formed and nematic-smectic mesomorphism was achieved via controlling solvent:antisolvent temperature difference (ΔTS:AS). The use of ΔTS:AS=49.5°C was associated with a nematic assembly, while intercalated smectic A layering was observed at ΔTS:AS=0°C, with both phases confined in the nanospheres at room temperature. The quasi emulsion system has not been investigated at the nanoscale to date and in contrary to the microscale, quasi nanoemulsion was observed over the solvent:antisolvent viscosity ratios of 1:7-1:1.4. Poly(acrylic acid) in the solvent phase exhibited a concentration dependent interaction when ITR formed NPs. This nanodroplet-based approach enabled the preparation of a stable ITR nanodispersion using Poloxamer 407 at 80°C, which was unachievable before using precipitation via nucleation. Findings of this work lay groundwork in terms of rationalised molecular assembly as a tool in designing pharmaceutical LC NPs with tailored properties. Copyright © 2015 Elsevier B.V. All rights reserved.

Magnetite and magnetite/silver core/shell nanoparticles with diluted magnet-like behavior

International Nuclear Information System (INIS)

Garza-Navarro, Marco; Torres-Castro, Alejandro; Gonzalez, Virgilio; Ortiz, Ubaldo; De la Rosa, Elder

2010-01-01

In the present work is reported the use of the biopolymer chitosan as template for the preparation of magnetite and magnetite/silver core/shell nanoparticles systems, following a two step procedure of magnetite nanoparticles in situ precipitation and subsequent silver ions reduction. The crystalline and morphological characteristics of both magnetite and magnetite/silver core/shell nanoparticles systems were analyzed by high resolution transmission electron microscopy (HRTEM) and nanobeam diffraction patterns (NBD). The results of these studies corroborate the core/shell morphology and the crystalline structure of the magnetite core and the silver shell. Moreover, magnetization temperature dependent, M(T), measurements show an unusual diluted magnetic behavior attributed to the dilution of the magnetic ordering in the magnetite and magnetite/silver core/shell nanoparticles systems. - Graphical abstract: Biopolymer chitosan was used as stabilization media to synthesize both magnetite and magnetite/silver core/shell nanoparticles. Results of HRTEM and NBD patterns confirm core/shell morphology of the obtained nanoparticles. It was found that the composites show diluted magnet-like behavior.

Synthesis of hydroxyapatite nanoparticles by a novel ultrasonic assisted with mixed hollow sphere template method

Science.gov (United States)

Gopi, D.; Indira, J.; Kavitha, L.; Sekar, M.; Mudali, U. Kamachi

Hydroxyapatite (HAP) is the main inorganic component of bone material and is widely used in various biomedical applications due to its excellent bioactivity and biocompatibility. In this paper, we have reported the synthesis of hydroxyapatite nanoparticles by a novel ultrasonic assisted mixed template directed method. In this method glycine-acrylic acid (GLY-AA) hollow spheres were used as an organic template which could be prepared by mixing of glycine with acrylic acid. The as-synthesized HAP nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM) and tunnelling electron microscope (TEM) to investigate the nature of bonding, crystallinity, size and shape. The thermal stability of as-synthesized nanoparticles was also investigated by the thermo gravimetric analysis (TGA). The effect of ultrasonic irradiation time on the crystallinity and size of the HAP nanoparticles in presence of glycine-acrylic acid hollow spheres template were investigated. From the inspection of the above results it is confirmed that the crystallinity and size of the HAP nanoparticles decrease with increasing ultrasonic irradiation time. Hence the proposed synthesis strategy provides a facile pathway to obtain nano sized HAP with high quality, suitable size and morphology.

Facile Large-scale synthesis of stable CuO nanoparticles

Science.gov (United States)

Nazari, P.; Abdollahi-Nejand, B.; Eskandari, M.; Kohnehpoushi, S.

2018-04-01

In this work, a novel approach in synthesizing the CuO nanoparticles was introduced. A sequential corrosion and detaching was proposed in the growth and dispersion of CuO nanoparticles in the optimum pH value of eight. The produced CuO nanoparticles showed six nm (±2 nm) in diameter and spherical feather with a high crystallinity and uniformity in size. In this method, a large-scale production of CuO nanoparticles (120 grams in an experimental batch) from Cu micro-particles was achieved which may met the market criteria for large-scale production of CuO nanoparticles.

Truck accident involving unirradiated nuclear fuel

International Nuclear Information System (INIS)

Carlson, R.W.; Fischer, L.E.

1993-01-01

In the early morning of Dec. 16, 1991, a severe accident occurred when a passenger vehicle traveling in the wrong direction collided with a tractor trailer carrying 24 unirradiated nuclear fuel assemblies in 12 containers on Interstate I-91 in Springfield, Massachusetts. This paper documents the mechanical circumstances of the accident and assesses the physical environment to which the containers were exposed and the response of the containers and their contents. The accident involved four impacts where the truck was struck by the car, impacted on the center guardrail, impacted on the outer concrete barrier and came to rest against the center guardrail. The impacts were followed by a fire that began in the engine compartment, spread to the tractor and cab, and eventually spread to the trailer and payload. The fire lasted for about three hours and the packages were involved in the fire for about two hours. As a result of the fire, the tractor-trailer was completely destroyed and the packages were exposed to flames with temperatures between 1,300 F and 1,800 F. The fuel assemblies remained intact during the accident and there was no release of any radioactive material during the accident. This was a very severe accident; however, the injuries were minor and at no time was the public health and safety at risk

SIZE OF BOEHMITE NANOPARTICLES BY TEM IMAGES ANALYSIS

Directory of Open Access Journals (Sweden)

Maxime Moreaud

2011-05-01

Full Text Available Transition aluminas, and especially the gamma type, are largely used as catalyst supports in refining and petrochemicals. Most studies focus on properties resulting from material texture and casting (specific surface, porous volume, pore shape and diameter. However, surface properties of alumina should be considered as well, as the catalytic activity is tightly related to the structure of exposed crystalline faces. As γ alumina results from controlled thermal treatment of boehmite γ-AlOOH by a topotactic transformation, the nature of exposed crystalline planes is related to the starting material. Therefore, the synthesis of the oxihydroxide γ-AlOOH, and especially size and shape of these particles, is critical in determining the relevant surface properties. Unlike often aggregated alumina, boehmite nanoparticles can be observed by TEM. Analysis of these TEM images can be performed to estimate the size of the boehmite nanoparticles. Information about morphology of the nanoparticles is obtained by the analysis of the covariance, modeling micrographs by a dilution model.

Nanoparticles with high payloads of pipemidic acid, a poorly soluble crystalline drug: drug-initiated polymerization and self-assembly approach

Directory of Open Access Journals (Sweden)

Elisabetta Pancani

2018-05-01

Full Text Available Nowadays, biodegradable polymers such as poly(lactic acid (PLA, poly(D,L-lactic-co-glycolic acid (PLGA and poly(ε-caprolactone (PCL remain the most common biomaterials to produce drug-loaded nanoparticles (NPs. Pipemidic acid (PIP is a poorly soluble antibiotic with a strong tendency to crystallize. PIP incorporation in PLA/PLGA NPs was challenging because of PIP crystals formation and burst release. As PIP had a poor affinity for the NPs, an alternative approach to encapsulation was used, consisting in coupling PIP to PCL. Thus, a PCL–PIP conjugate was successfully synthesized by an original drug-initiated polymerization in a single step without the need of catalyst. PCL–PIP was characterized by NMR, IR, SEC and mass spectrometry. PCL–PIP was used to prepare self-assembled NPs with PIP contents as high as 27% (w/w. The NPs were characterized by microscopy, DLS, NTA and TRPS. This study paves the way towards the production of NPs with high antibiotic payloads by drug-initiated polymerization. Further studies will deal with the synthesis of novel polymer–PIP conjugates with ester bonds between the drug and PCL. PIP can be considered as a model drug and the strategy developed here could be extended to other challenging antibiotics or anticancer drugs and employed to efficiently incorporate them in NPs. KEY WORDS: Pipemidic acid, Nanoparticle, Antibiotic, Nanoprecipitation, Crystalline drug, Drug-initiated   polymerization

HRTEM Study of the Role of Nanoparticles in ODS Ferritic Steel

Energy Technology Data Exchange (ETDEWEB)

Hsiung, L; Tumey, S; Fluss, M; Serruys, Y; Willaime, F

2011-08-30

Structures of nanoparticles and their role in dual-ion irradiated Fe-16Cr-4.5Al-0.3Ti-2W-0.37Y{sub 2}O{sub 3} (K3) ODS ferritic steel produced by mechanical alloying (MA) were studied using high-resolution transmission electron microscopy (HRTEM) techniques. The observation of Y{sub 4}Al{sub 2}O{sub 9} complex-oxide nanoparticles in the ODS steel imply that decomposition of Y{sub 2}O{sub 3} in association with internal oxidation of Al occurred during mechanical alloying. HRTEM observations of crystalline and partially crystalline nanoparticles larger than {approx}2 nm and amorphous cluster-domains smaller than {approx}2 nm provide an insight into the formation mechanism of nanoparticles/clusters in MA/ODS steels, which we believe involves solid-state amorphization and re-crystallization. The role of nanoparticles/clusters in suppressing radiation-induced swelling is revealed through TEM examinations of cavity distributions in (Fe + He) dual-ion irradiated K3-ODS steel. HRTEM observations of helium-filled cavities (helium bubbles) preferably trapped at nanoparticle/clusters in dual-ion irradiated K3-ODS are presented.

Amorphous nanoparticles — Experiments and computer simulations

International Nuclear Information System (INIS)

Hoang, Vo Van; Ganguli, Dibyendu

2012-01-01

The data obtained by both experiments and computer simulations concerning the amorphous nanoparticles for decades including methods of synthesis, characterization, structural properties, atomic mechanism of a glass formation in nanoparticles, crystallization of the amorphous nanoparticles, physico-chemical properties (i.e. catalytic, optical, thermodynamic, magnetic, bioactivity and other properties) and various applications in science and technology have been reviewed. Amorphous nanoparticles coated with different surfactants are also reviewed as an extension in this direction. Much attention is paid to the pressure-induced polyamorphism of the amorphous nanoparticles or amorphization of the nanocrystalline counterparts. We also introduce here nanocomposites and nanofluids containing amorphous nanoparticles. Overall, amorphous nanoparticles exhibit a disordered structure different from that of corresponding bulks or from that of the nanocrystalline counterparts. Therefore, amorphous nanoparticles can have unique physico-chemical properties differed from those of the crystalline counterparts leading to their potential applications in science and technology.

Oxide particle size distribution from shearing irradiated and unirradiated LWR fuels in Zircaloy and stainless steel cladding: significance for risk assessment

Energy Technology Data Exchange (ETDEWEB)

Davis, W. Jr.; West, G.A.; Stacy, R.G.

1979-03-22

Sieve fractionation was performed with oxide particles dislodged during shearing of unirradiated or irradiated fuel bundles or single rods of UO/sub 2/ or 96 to 97% ThO/sub 2/--3 to 4% UO/sub 2/. Analyses of these data by nonlinear least-squares techniques demonstrated that the particle size distribution is lognormal. Variables involved in the numerical analyses include lognormal median size, lognormal standard deviation, and shear cut length. Sieve-fractionation data are presented for unirradiated bundles of stainless-steel-clad or Zircaloy-2-clad UO/sub 2/ or ThO/sub 2/--UO/sub 2/ sheared into lengths from 0.5 to 2.0 in. Data are also presented for irradiated single rods (sheared into lengths of 0.25 to 2.0 in.) of Zircaloy-2-clad UO/sub 2/ from BWRs and of Zircaloy-4-clad UO/sub 2/ from PWRs. Median particle sizes of UO/sub 2/ from shearing irradiated stainless-steel-clad fuel ranged from 103 to 182 ..mu..m; particle sizes of ThO/sub 2/--UO/sub 2/, under these same conditions, ranged from 137 to 202 ..mu..m. Similarly, median particle sizes of UO/sub 2/ from shearing unirradiated Zircaloy-2-clad fuel ranged from 230 to 957 ..mu..m. Irradiation levels of fuels from reactors ranged from 9,000 to 28,000 MWd/MTU. In general, particle sizes from shearing these irradiated fuels are larger than those from the unirradiated fuels; however, unirradiated fuel from vendors was not available for performing comparative shearing experiments. In addition, variations in particle size parameters pertaining to samples of a single vendor varied as much as those between different vendors. The fraction of fuel dislodged from the cladding is nearly proportional to the reciprocal of the shear cut length, until the cut length attains some minimum value below which all fuel is dislodged. Particles of fuel are generally elongated with a long-to-short axis ratio usually less than 3. Using parameters of the lognormal distribution estimates can be made of fractions of dislodged fuel having

Characterization of starch films containing starch nanoparticles: part 1: physical and mechanical properties.

Science.gov (United States)

Shi, Ai-Min; Wang, Li-Jun; Li, Dong; Adhikari, Benu

2013-07-25

We report, for the first time, the preparation method and characteristics of starch films incorporating spray dried and vacuum freeze dried starch nanoparticles. Physical properties of these films such as morphology, crystallinity, water vapor permeability (WVP), opacity, and glass transition temperature (Tg) and mechanical properties (strain versus temperature, strain versus stress, Young's modulus and toughness) were measured. Addition of both starch nanoparticles in starch films increased roughness of surface, lowered degree of crystallinity by 23.5%, WVP by 44% and Tg by 4.3°C, respectively compared to those of starch-only films. Drying method used in preparation of starch nanoparticles only affected opacity of films. The incorporation of nanoparticles in starch films resulted into denser films due to which the extent of variation of strain with temperature was much lower. The toughness and Young's modulus of films containing both types of starch nanoparticles were lower than those of control films especially at <100°C. Copyright © 2012 Elsevier Ltd. All rights reserved.

Tensile and fracture toughness properties of copper alloys and their HIP joints with austenitic stainless steel in unirradiated and neutron irradiated condition

International Nuclear Information System (INIS)

Taehtinen, S.; Pyykkoenen, M.; Singh, B.N.; Toft, P.

1998-03-01

The tensile strength and ductility of unirradiated CuAl25 IG0 and CuCrZr alloys decreased continuously with increasing temperature up to 350 deg C. Fracture toughness of unirradiated CuAl25 IG0 alloy decreased continuously with increasing temperature from 20 deg C to 350 deg C whereas the fracture toughness of unirradiated CuCrZr alloy remained almost constant at temperatures up to 100 deg C, was decreased significantly at 200 deg C and slightly increased at 350 deg C. Fracture toughness of HIP joints were lower than that of corresponding copper alloy and fracture path in HIP joint specimen was always within copper alloy side of the joint. Neutron irradiation to a dose level of 0.3 dpa resulted in hardening and reduction in uniform elongation to about 2-4% at 200 deg C in both copper alloys. At higher temperatures softening was observed and uniform elongation increased to about 5% and 16% for CuAl25 IG0 and CuCrZr alloys, respectively. Fracture toughness of CuAl25 IG0 alloy reduced markedly due to neutron irradiation in the temperature range from 20 deg C to 350 deg C. The fracture toughness of the irradiated CuCrZr alloy also decreased in the range from 20 deg C to 350 deg C, although it remained almost unaffected at temperatures below 200 deg C and decreased significantly at 350 deg C when compared with that of unirradiated CuCrZr alloy. (orig.)

The effect of compressive stress on the Young's modulus of unirradiated and irradiated nuclear graphites

International Nuclear Information System (INIS)

Oku, T.; Usui, T.; Ero, M.; Fukuda, Y.

1977-01-01

The Young's moduli of unirradiated and high temperature (800 to 1000 0 C) irradiated graphites for HTGR were measured by the ultrasonic method in the direction of applied compressive stress during and after stressing. The Young's moduli of all the tested graphites decreased with increasing compressive stress both during and after stressing. In order to investigate the reason for the decrease in Young's modulus by applying compressive stress, the mercury pore diameter distributions of a part of the unirradiated and irradiated specimens were measured. The change in pore distribution is believed to be associated with structural changes produced by irradiation and compressive stressing. The residual strain, after removing the compressive stress, showed a good correlation with the decrease in Young's modulus caused by the compressive stress. The decrease in Young's modulus by applying compressive stress was considered to be due to the increase in the mobile dislocation density and the growth or formation of cracks. The results suggest, however, that the mechanism giving the larger contribution depends on the brand of graphite, and in anisotropic graphite it depends on the direction of applied stress and the irradiation conditions. (author)

Preparation of antimony-doped nanoparticles by hydrothermal method

Institute of Scientific and Technical Information of China (English)

JIANG Ming-xi; YANG Tian-zu; GU Ying-ying; DU Zuo-juan; LIU Jian-ling

2005-01-01

Antimony-doped tin oxide(ATO) nanoparticles were prepared by the mild hydrothermal method at 200 ℃ using sodium stannate, antimony oxide, sodium hydroxide and sulfuric acid as the starting materials. The doped powders were examined by differential thermal analysis(DTA), X-ray diffractometry(XRD) and transmission electron microscopy(TEM). The doping levels of antimony were determined by volumetric method and iodimetry.The results show that antimony is incorporated into the crystal lattice of tin oxide and the doping levels of antimony in the resulting powders are 2.4%, 4.3 % and 5.1 % (molar fraction). The mean particle size of ATO nanoparticles is in the range of 25 - 30 nm. The effects of antimony doping level on the crystalline size and crystallinity were also discussed.

Deposition of Crystalline Hydroxyapatite Nanoparticles on Y-TZP Ceramic: A Potential Solution to Enhance Bonding Characteristics of Y-TZP Ceramics

Directory of Open Access Journals (Sweden)

Abbas Azari

2017-08-01

Full Text Available Objectives: Many advantages have been attributed to dental zirconia ceramics in terms of mechanical and physical properties; however, the bonding ability of this material to dental structure and/or veneering ceramics has always been a matter of concern. On the other hand, hydroxyapatite (HA shows excellent biocompatibility and good bonding ability to tooth structure, with mechanically unstable and brittle characteristics, that make it clinically unacceptable for use in high stress bearing areas. The main purpose of this study was to introduce two simple yet practical methods to deposit the crystalline HA nanoparticles on zirconia ceramics. Materials and Methods: zirconia blocks were treated with HA via two different deposition methods namely thermal coating and air abrasion. Specimens were analyzed by scanning electron microscopy, energy dispersive spectroscopy (EDS and X-ray diffraction (XRD.Results: In both groups, the deposition techniques used were successfully accomplished, while the substrate showed no structural change. However, thermal coating group showed a uniform deposition of crystalline HA but in air abrasion method, there were dispersed thin islands of HA.Conclusions: Thermal coating method has the potential to significantly alter the surface characteristics of zirconia. The simple yet practical nature of the proposed method may be able to shift the bonding paradigm of dental zirconia ceramics. This latter subject needs to be addressed in future investigations.Keywords: Zirconium Oxide; Hydroxyapatites; Dental Bonding; Microscopy, Electron, Scanning; X-Ray Diffraction; Spectrometry, X-Ray Emission

Fabrication and Optical Characterization of Zinc Oxide Nanoparticles Prepared via a Simple Sol-gel Method

Directory of Open Access Journals (Sweden)

K. Hedayati

2015-10-01

Full Text Available In this research zinc oxide (ZnO nano-crystalline powders were prepared by sol-gel method using zinc acetate. The ZnO nanoparticles were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, ultraviolet-visible (UV-Vis, Fourier transform infra-red (FT-IR and energy dispersive X-ray (EDX spectroscopy. The structure of nanoparticles was studied using XRD pattern. The crystallite size of ZnO nanoparticles was calculated by Debye–Scherrer formula. Morphology of nano-crystals was observed and investigated using the SEM. The grain size of zinc oxide nanoparticles were in suitable agreement with the crystalline size calculated by XRD results. The optical properties of particles were studied with UV-Vis an FTIR absorption spectrum. The Raman spectrum measurements were carried out using a micro-laser Raman spectrometer forms the ZnO nanoparticles. At the end studied the effect of calcined temperature on the photoluminescence (PL emission of ZnO nanoparticles.

Template synthesis of highly crystalline and monodisperse iron oxide pigments of nanosize

International Nuclear Information System (INIS)

Sreeram, Kalarical Janardhanan; Indumathy, Ramasamy; Rajaram, Ananthanarayanan; Nair, Balachandran Unni; Ramasami, Thirumalachari

2006-01-01

Synthesis of highly crystalline and monodisperse iron oxide nanoparticles is reported. The separation of Fe centers through site-specific binding to a polysaccharide-alginate matrix enables the generation of particles with a monodisperse or narrow size distribution character, resulting in transparent pigments. Site-specific interactions coupled with gel like character of alginate is proposed as the mechanism behind generation of lower particle sizes. Alginate-Fe complexes developed were subjected to heat treatment to provide for crystalline character and development of hematite (α-Fe 2 O 3 ). Conditions most ideal for achieving monodispersity and lower sizes have been optimized and confirmed through microscopic and photon correlation spectroscopic measurements

Butea monosperma bark extract mediated green synthesis of silver nanoparticles: Characterization and biomedical applications

Directory of Open Access Journals (Sweden)

Sutanuka Pattanayak

2017-09-01

Full Text Available The work deals with an environmentally benign process for the synthesis of silver nanoparticle using Butea monosperma bark extract which is used both as a reducing as well as capping agent at room temperature. The reaction mixture turned brownish yellow after about 24 h and an intense surface plasmon resonance (SPR band at around 424 nm clearly indicates the formation of silver nanoparticles. Fourier transform-Infrared (FT-IR spectroscopy showed that the nanoparticles were capped with compounds present in the plant extract. Formation of crystalline fcc silver nanoparticles is analysed by XRD data and the SAED pattern obtained also confirms the crystalline behaviour of the Ag nanoparticles. The size and morphology of these nanoparticles were studied using High Resolution Transmission Electron Microscopy (HRTEM which showed that the nanoparticles had an average dimension of ∼35 nm. A larger DLS data of ∼98 nm shows the presence of the stabilizer on the nanoparticles surface. The bio-synthesized silver nanoparticles revealed potent antibacterial activity against human bacteria of both Gram types. In addition these biologically synthesized nanoparticles also proved to exhibit excellent cytotoxic effect on human myeloid leukemia cell line, KG-1A with IC50 value of 11.47 μg/mL.

Dry Powder Precursors of Cubic Liquid Crystalline Nanoparticles (cubosomes)

International Nuclear Information System (INIS)

Spicer, Patrick T.; Small, William B.; Small, William B.; Lynch, Matthew L.; Burns, Janet L.

2002-01-01

Cubosomes are dispersed nanostructured particles of cubic phase liquid crystal that have stimulated significant research interest because of their potential for application in controlled-release and drug delivery. Despite the interest, cubosomes can be difficult to fabricate and stabilize with current methods. Most of the current work is limited to liquid phase processes involving high shear dispersion of bulk cubic liquid crystalline material into sub-micron particles, limiting application flexibility. In this work, two types of dry powder cubosome precursors are produced by spray-drying: (1) starch-encapsulated monoolein is produced by spray-drying a dispersion of cubic liquid crystalline particles in an aqueous starch solution and (2) dextran-encapsulated monoolein is produced by spray-drying an emulsion formed by the ethanol-dextran-monoolein-water system. The encapsulants are used to decrease powder cohesion during drying and to act as a soluble colloidal stabilizer upon hydration of the powders. Both powders are shown to form (on average) 0.6 μm colloidally-stable cubosomes upon addition to water. However, the starch powders have a broader particle size distribution than the dextran powders because of the relative ease of spraying emulsions versus dispersions. The developed processes enable the production of nanostructured cubosomes by end-users rather than just specialized researchers and allow tailoring of the surface state of the cubosomes for broader application

Effect of silver nanoparticles' generation routes on the morphology, oxygen, and water transport properties of starch nanocomposite films

Energy Technology Data Exchange (ETDEWEB)

Cheviron, Perrine; Gouanvé, Fabrice, E-mail: fabrice.gouanve@univ-lyon1.fr; Espuche, Eliane, E-mail: eliane.espuche@univ-lyon1.fr [Université de Lyon (France)

2015-09-15

A strategy involving the preparation of silver nanoparticles in a biodegradable polymer stemming from an ex situ or an in situ method using a green chemistry process is reported. The influence of the reducing agent concentration and the silver nanoparticles' generation route were investigated on the structure, the morphology, and the properties of the nanocomposite films. Two distinct silver nanoparticle populations in size were highlighted from the ex situ route (diameter around 5 nm for the first one and from 20 to 50 nm for the second one), whereas one population was highlighted from the in situ route (around 10 nm). No modification on the crystalline structure of the starch matrix was observed in presence of silver. Crystalline silver nanoparticles were obtained only from the in situ generation route. The decrease of the water sorption and the improvement of water and oxygen barrier properties were found to be not dependent on the reducing agent concentration but mainly on the crystalline structure of the silver nanoparticles associated to the presence of strong interface between the silver nanoparticles and the starch polymer matrix.

Sperm quantity and size variation in un-irradiated and irradiated males of the malaria mosquito Anopheles arabiensis Patton

NARCIS (Netherlands)

Helinski, M.; Knols, B.G.J.

2009-01-01

Anopheles mosquitoes are important candidates for genetic control strategies. However, little is known about sperm quality and quantity as determinants of male reproductive success. In this study, sperm quantity and length variation were assessed in testes of un-irradiated and irradiated Anopheles

Erythrokinetics in mice bearing tumours in either preirradiated or unirradiated tissue

International Nuclear Information System (INIS)

Jirtle, R.L.; Clifton, K.H.

1978-01-01

Experiments were designed to clarify the causes of anaemia in hosts bearing tumours in either unirradiated or preirradiated tissue. Isotopic methods are described which enable the estimation of erythrocyte destruction and production rates, and the potential red cell life spans in tumour-bearing animals. In this experimental system, anaemia (a) is in large part due to accelerated random erythrocyte loss, (b) is exacerbated as tumours grow by a progressive reduction in the potential erythrocyte life span due to intrinsic erythrocyte defects. (c) is accompanied by an increase in erythrocyte production of six- to ten-fold and (d) is postponed in onset and decreased in magnitude by preirradiation of the tumour transplant site. (author)

Erythrokinetics in mice bearing tumours in either preirradiated or unirradiated tissue

Energy Technology Data Exchange (ETDEWEB)

Jirtle, R L; Clifton, K H [Wisconsin Univ., Madison (USA). Div. of Clinical Oncology

1978-11-01

Experiments were designed to clarify the causes of anaemia in hosts bearing tumours in either unirradiated or preirradiated tissue. Isotopic methods are described which enable the estimation of erythrocyte destruction and production rates, and the potential red cell life spans in tumour-bearing animals. In this experimental system, anaemia (a) is in large part due to accelerated random erythrocyte loss, (b) is exacerbated as tumours grow by a progressive reduction in the potential erythrocyte life span due to intrinsic erythrocyte defects. (c) is accompanied by an increase in erythrocyte production of six- to ten-fold and (d) is postponed in onset and decreased in magnitude by preirradiation of the tumour transplant site.

Synthesis of hydroxyapatite nanoparticles by a novel ultrasonic assisted with mixed hollow sphere template method.

Science.gov (United States)

Gopi, D; Indira, J; Kavitha, L; Sekar, M; Mudali, U Kamachi

2012-07-01

Hydroxyapatite (HAP) is the main inorganic component of bone material and is widely used in various biomedical applications due to its excellent bioactivity and biocompatibility. In this paper, we have reported the synthesis of hydroxyapatite nanoparticles by a novel ultrasonic assisted mixed template directed method. In this method glycine-acrylic acid (GLY-AA) hollow spheres were used as an organic template which could be prepared by mixing of glycine with acrylic acid. The as-synthesized HAP nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM) and tunnelling electron microscope (TEM) to investigate the nature of bonding, crystallinity, size and shape. The thermal stability of as-synthesized nanoparticles was also investigated by the thermo gravimetric analysis (TGA). The effect of ultrasonic irradiation time on the crystallinity and size of the HAP nanoparticles in presence of glycine-acrylic acid hollow spheres template were investigated. From the inspection of the above results it is confirmed that the crystallinity and size of the HAP nanoparticles decrease with increasing ultrasonic irradiation time. Hence the proposed synthesis strategy provides a facile pathway to obtain nano sized HAP with high quality, suitable size and morphology. Copyright © 2012 Elsevier B.V. All rights reserved.

Hydrophobic silica nanoparticles as reinforcing filler for poly (lactic acid polymer matrix

Directory of Open Access Journals (Sweden)

Pilić Branka M.

2016-01-01

Full Text Available Properties of poly (lactic acid (PLA and its nanocomposites, with silica nanoparticles (SiO2, as filler were investigated. Neat PLA films and PLA films with different percentage of hydrophobic fumed silica nanoparticles (0.2, 0.5, 1, 2, 3 and 5 wt. % were prepared by solution casting method. Several tools were used to characterize the influence of different silica content on crystalline behavior, and thermal, mechanical and barrier properties of PLA/SiO2 nanocomposites. Results from scanning electron microscope (SEM showed that the nanocomposite preparation and selection of specific hydrophobic spherical nano filler provide a good dispersion of the silica nanoparticles in the PLA matrix. Addition of silica nanoparticles improved mechanical properties, the most significant improvement being observed for lowest silica content (0.2wt.%. Barrier properties were improved for all measured gases at all loadings of silica nanoparticles. The degree of crystallinity for PLA slightly increased by adding 0.2 and 0.5 wt. % of nano filler. [Projekat Ministarstva nauke Republike Srbije, br. III46001

Single step thermal decomposition approach to prepare supported γ-Fe2O3 nanoparticles

International Nuclear Information System (INIS)

Sharma, Geetu; Jeevanandam, P.

2012-01-01

γ-Fe 2 O 3 nanoparticles supported on MgO (macro-crystalline and nanocrystalline) were prepared by an easy single step thermal decomposition method. Thermal decomposition of iron acetylacetonate in diphenyl ether, in the presence of the supports followed by calcination, leads to iron oxide nanoparticles supported on MgO. The X-ray diffraction results indicate the stability of γ-Fe 2 O 3 phase on MgO (macro-crystalline and nanocrystalline) up to 1150 °C. The scanning electron microscopy images show that the supported iron oxide nanoparticles are agglomerated while the energy dispersive X-ray analysis indicates the presence of iron, magnesium and oxygen in the samples. Transmission electron microscopy images indicate the presence of smaller γ-Fe 2 O 3 nanoparticles on nanocrystalline MgO. The magnetic properties of the supported magnetic nanoparticles at various calcination temperatures (350-1150 °C) were studied using a superconducting quantum interference device which indicates superparamagnetic behavior.

Spectral luminescent properties of bacteriochlorin and aluminum phthalocyanine nanoparticles as hydroxyapatite implant surface coating

Directory of Open Access Journals (Sweden)

Yu. S. Maklygina

2016-01-01

Full Text Available The development and the spectral research of unique coating as crystalline nanoparticles of IR photosensitizers were performed for the creation of hydroxyapatite implants with photobactericidal properties. It has been proved that by the interaction of nanoparticles covering implant with the polar solvent, which simulates the interaction of the implant with the biocomponents in vivo (fast proliferating and with immunocompetent cells, photosensitizers nanoparticles change the spectroscopic properties, becoming fluorescent and phototoxic. Thus, the developed coating based on crystalline photosensitizer nanoparticles with studied specific properties should have antibacterial, anti-inflammatory effect by the photodynamic treatment in the near implant area. This research opens the prospect of the local prevention of inflammatory and autoimmune reactions in the area of implantation. The results of the study suggest a promising this technology in order to create implants with photobactericidal properties.

Characterization of the oleic acid/iron oxide nanoparticle interface by magnetic resonance

Energy Technology Data Exchange (ETDEWEB)

Masur, S., E-mail: sabrina.masur@uni-due.de; Zingsem, B.; Marzi, T.; Meckenstock, R.; Farle, M.

2016-10-01

The synthesis of colloidal nanoparticles involves surfactant molecules, which bind to the particle surface and stabilize nanoparticles against aggregation. In many cases these protecting shells also can be used for further functionalization. In this study, we investigated monodisperse single crystalline iron oxide core/shell nanoparticles (Fe{sub x}O{sub y}-NPs) in situ covered with an oleic acid layer which showed two electron spin resonance (ESR) signals. The nanoparticles with the ligands attached were characterized by transmission electron microscopy (TEM) and ferro- and paramagnetic resonance (FMR, EPR). Infrared spectroscopy confirmed the presence of the functional groups and revealed that the oleic acid (OA) is chemisorbed as a carboxylate on the iron oxide and is coordinated symmetrically to the oxide atoms. We show that the EPR signal of the OA ligand molecule can be used as a local probe to determine the temperature changes at the surface of the nanoparticle. - Highlights: • Monodisperse single crystalline iron oxide core/shell nanoparticles (Fe{sub x}O{sub y}-NPs) in situ covered with an oleic acid layer two electron spin resonance (ESR) signals. • We show that the EPR signal of the OA ligand molecule can be used as a local probe to determine the temperature changes at the surface of the nanoparticle.

Opuntia ficus indica peel derived pectin mediated hydroxyapatite nanoparticles: Synthesis, spectral characterization, biological and antimicrobial activities

Science.gov (United States)

Gopi, D.; Kanimozhi, K.; Kavitha, L.

2015-04-01

In the present study, we have adapted a facile and efficient green route for the synthesis of HAP nanoparticles using pectin as a template which was extracted from the peel of prickly pear (Opuntia ficus indica) fruits. The concentration of pectin plays a major role in the behavior of crystallinity, purity, morphology as well as biological property of the as-synthesized HAP nanoparticles. The extracted pectin and the as-synthesized nanoparticles were characterized by various analytical techniques. The in vitro apatite formation on the surface of the as-synthesized nanoparticles in simulated body fluid (SBF) for various days showed an enhanced bioactivity. Also, the antimicrobial activity was investigated using various microorganisms. All the results revealed the formation of pure, low crystalline and discrete granular like HAP nanoparticles of size around 25 nm with enhanced biological and antimicrobial activities. Hence the as-synthesized nanoparticles can act as a better bone regenerating material in the field of biomedicine.

Opuntia ficus indica peel derived pectin mediated hydroxyapatite nanoparticles: synthesis, spectral characterization, biological and antimicrobial activities.

Science.gov (United States)

Gopi, D; Kanimozhi, K; Kavitha, L

2015-04-15

In the present study, we have adapted a facile and efficient green route for the synthesis of HAP nanoparticles using pectin as a template which was extracted from the peel of prickly pear (Opuntia ficus indica) fruits. The concentration of pectin plays a major role in the behavior of crystallinity, purity, morphology as well as biological property of the as-synthesized HAP nanoparticles. The extracted pectin and the as-synthesized nanoparticles were characterized by various analytical techniques. The in vitro apatite formation on the surface of the as-synthesized nanoparticles in simulated body fluid (SBF) for various days showed an enhanced bioactivity. Also, the antimicrobial activity was investigated using various microorganisms. All the results revealed the formation of pure, low crystalline and discrete granular like HAP nanoparticles of size around 25 nm with enhanced biological and antimicrobial activities. Hence the as-synthesized nanoparticles can act as a better bone regenerating material in the field of biomedicine. Copyright © 2015 Elsevier B.V. All rights reserved.

Lyotropic Liquid Crystalline Nanoparticles of Amphotericin B: Implication of Phytantriol and Glyceryl Monooleate on Bioavailability Enhancement.

Science.gov (United States)

Jain, Sanyog; Yadav, Pooja; Swami, Rajan; Swarnakar, Nitin Kumar; Kushwah, Varun; Katiyar, Sameer S

2018-05-01

Implication of different dietary specific lipids such as phytantriol (PT) and glyceryl monooleate (GMO) on enhancing the oral bioavailability of amphotericin B (AmB) was examined. Liquid crystalline nanoparticles (LCNPs) were prepared using hydrotrope method, followed by in vitro characterization, Caco-2 cell monolayer uptake, and in vivo pharmacokinetic and toxicity evaluation. Optimized AmB-LCNPs displayed small particle size (< 210 nm) with a narrow distribution (~ 0.2), sustained drug release and high gastrointestinal stability, and reduced hemolytic toxicity. PLCNPs presented slower release, i.e., ~ 80% as compared to ~ 90% release in case of GLCNPs after 120 h. Significantly higher uptake in Caco-2 monolayer substantiated the role of LCNPs in increasing the intestinal permeability followed by increased drug titer in plasma. Pharmacokinetic studies demonstrated potential of PT in enhancing the bioavailability (approximately sixfold) w.r.t. of its native counterpart with reduced nephrotoxicity as presented by reduced nephrotoxicity biomarkers and histology studies. These studies established usefulness of PLCNPs over GLCNPs and plain drug. It can be concluded that acid-resistant lipid, PT, can be utilized efficiently as an alternate lipid for the preparation of LCNPs to enhance bioavailability and to reduce nephrotoxicity of the drug as compared to other frequently used lipid, i.e., GMO.

Flow rate effect on the structure and morphology of molybdenum oxide nanoparticles deposited by atmospheric-pressure microplasma processing

International Nuclear Information System (INIS)

Bose, Arumugam Chandra; Shimizu, Yoshiki; Mariotti, Davide; Sasaki, Takeshi; Terashima, Kazuo; Koshizaki, Naoto

2006-01-01

Nanoparticles of crystalline molybdenum oxide were prepared by changing the flow rate of plasma gas (2% oxygen balanced by Ar) using an atmospheric-pressure microplasma technique. The morphology and crystalline structure of the nanoparticles were characterized by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The FESEM results revealed that the shape of the deposited nanoparticles depended on the plasma gas flow rate. The TEM results supported the FESEM observations. The transmission electron diffraction (TED) pattern revealed that the obtained nanoparticles changed from MoO 2 to MoO 3 with the flow-rate increase, and correspondingly the nanoparticle size drastically decreased. A process mechanism is proposed from the observations of optical emission spectroscopy (OES) during the process and consumed wire surface analysis from x-ray photoelectron spectroscopy (XPS) and FESEM studies

Molecular dynamics study on interfacial thermal conductance of unirradiated and irradiated SiC/C

International Nuclear Information System (INIS)

Wang, Qingyu; Wang, Chenglong; Zhang, Yue; Li, Taosheng

2014-01-01

SiC f /SiC composite materials have been considered as candidate structural materials for several types of advanced nuclear reactors. Both experimental and computer simulations studies have revealed the degradation of thermal conductivity for this material after irradiation. The objective of this study is to investigate the effect of SiC/graphite interface structure and irradiation on the interfacial thermal conductance by using molecular dynamics simulation. Five SiC/graphite composite models were created with different interface structures, and irradiation was introduced near the interfaces. Thermal conductance was calculated by means of reverse-NEMD method. Results show that there is a positive correlation between the interfacial energy and interfacial C–Si bond quantity, and irradiated models showed higher interfacial energy compared with their unirradiated counterparts. Except the model with graphite atom plane parallel to the interface, the interfacial thermal conductance of unirradiated and irradiated (1000 eV) models, increases as the increase of interfacial energy, respectively. For all irradiated models, lattice defects are of importance in impacting the interfacial thermal conductance depending on the interface structure. For the model with graphite layer parallel to the interface, the interfacial thermal conductance increased after irradiation, for the other models the interfacial thermal conductance decreased. The vibrational density of states of atoms in the interfacial region was calculated to analyze the phonon mismatch at the interface

Thermoelectric Performance Enhancement by Surrounding Crystalline Semiconductors with Metallic Nanoparticles

Science.gov (United States)

Kim, Hyun-Jung; King, Glen C.; Park, Yeonjoon; Lee, Kunik; Choi, Sang H.

2011-01-01

Direct conversion of thermal energy to electricity by thermoelectric (TE) devices may play a key role in future energy production and utilization. However, relatively poor performance of current TE materials has slowed development of new energy conversion applications. Recent reports have shown that the dimensionless Figure of Merit, ZT, for TE devices can be increased beyond the state-of-the-art level by nanoscale structuring of materials to reduce their thermal conductivity. New morphologically designed TE materials have been fabricated at the NASA Langley Research Center, and their characterization is underway. These newly designed materials are based on semiconductor crystal grains whose surfaces are surrounded by metallic nanoparticles. The nanoscale particles are used to tailor the thermal and electrical conduction properties for TE applications by altering the phonon and electron transport pathways. A sample of bismuth telluride decorated with metallic nanoparticles showed less thermal conductivity and twice the electrical conductivity at room temperature as compared to pure Bi2Te3. Apparently, electrons cross easily between semiconductor crystal grains via the intervening metallic nanoparticle bridges, but phonons are scattered at the interfacing gaps. Hence, if the interfacing gap is larger than the mean free path of the phonon, thermal energy transmission from one grain to others is reduced. Here we describe the design and analysis of these new materials that offer substantial improvements in thermoelectric performance.

Preparation of gold nanoparticles by arc discharge in water

International Nuclear Information System (INIS)

Lung, Jen-Kuang; Huang, Jen-Chuen; Tien, Der-Chi; Liao, Chih-Yu; Tseng, Kuo-Hsiung; Tsung, Tsing-Tshin; Kao, Wen-Shiow; Tsai, Teh-Hua; Jwo, Ching-Song; Lin, Hong-Ming; Stobinski, Leszek

2007-01-01

Gold nanoparticles have been attracting attention due to their extensive application in chemistry, physics, material science, electronics, catalysis and bionanotechnology. Synthesis of gold nanoparticles often involves toxic and expensive physical-chemistry methods. Preparation of gold nanoparticles by arc discharge in water is proposed for the first time. Fabrication of gold nanostructures in deionized water has been successfully established. The evidence of gold particles' light absorbance reveals a unique surface plasmon resonance for Au nanoparticles suspended in deionized water. Gold nanostructures uniformly dispersed in water, their UV-Vis absorption and crystalline size are shown. Our experimental results demonstrate that fabrication of gold nanoparticles by arc discharge in water is an alternative, cheap, effective and environmentally friendly method

Biotransformation of hexavalent chromium into extracellular chromium(III) oxide nanoparticles using Schwanniomyces occidentalis.

Science.gov (United States)

Mohite, Pallavi T; Kumar, Ameeta Ravi; Zinjarde, Smita S

2016-03-01

To demonstrate biotransformation of toxic Cr(VI) ions into Cr2O3 nanoparticles by the yeast Schwanniomyces occidentalis. Reaction mixtures containing S. occidentalis NCIM 3459 and Cr(VI) ions that were initially yellow turned green after 48 h incubation. The coloration was due to the synthesis of chromium (III) oxide nanoparticles (Cr2O3NPs). UV-Visible spectra of the reaction mixtures showed peaks at 445 and 600 nm indicating (4)A2g → (4)T1g and (4)A2g → (4)T2g transitions in Cr2O3, respectively. FTIR profiles suggested the involvement of carboxyl and amide groups in nanoparticle synthesis and stabilization. The Cr2O3NPs ranged between 10 and 60 nm. Their crystalline nature was evident from the selective area electron diffraction and X-ray diffraction patterns. Energy dispersive spectra confirmed the chemical composition of the nanoparticles. These biogenic nanoparticles could find applications in different fields. S. occidentalis mediated biotransformation of toxic Cr(VI) ions into crystalline extracellular Cr2O3NPs under benign conditions.

Statistical analysis of support thickness and particle size effects in HRTEM imaging of metal nanoparticles

International Nuclear Information System (INIS)

House, Stephen D.; Bonifacio, Cecile S.; Grieshaber, Ross V.; Li, Long; Zhang, Zhongfan; Ciston, Jim; Stach, Eric A.; Yang, Judith C.

2016-01-01

High-resolution transmission electron microscopy (HRTEM) examination of nanoparticles requires their placement on some manner of support – either TEM grid membranes or part of the material itself, as in many heterogeneous catalyst systems – but a systematic quantification of the practical imaging limits of this approach has been lacking. Here we address this issue through a statistical evaluation of how nanoparticle size and substrate thickness affects the ability to resolve structural features of interest in HRTEM images of metallic nanoparticles on common support membranes. The visibility of lattice fringes from crystalline Au nanoparticles on amorphous carbon and silicon supports of varying thickness was investigated with both conventional and aberration-corrected TEM. Over the 1–4 nm nanoparticle size range examined, the probability of successfully resolving lattice fringes differed significantly as a function both of nanoparticle size and support thickness. Statistical analysis was used to formulate guidelines for the selection of supports and to quantify the impact a given support would have on HRTEM imaging of crystalline structure. For nanoparticles ≥1 nm, aberration-correction was found to provide limited benefit for the purpose of visualizing lattice fringes; electron dose is more predictive of lattice fringe visibility than aberration correction. These results confirm that the ability to visualize lattice fringes is ultimately dependent on the signal-to-noise ratio of the HRTEM images, rather than the point-to-point resolving power of the microscope. This study provides a benchmark for HRTEM imaging of crystalline supported metal nanoparticles and is extensible to a wide variety of supports and nanostructures. - Highlights: • The impact of supports on imaging nanoparticle lattice structure is quantified. • Visualization probabilities given particle size and support thickness are estimated. • Aberration-correction provided limited benefit

Statistical analysis of support thickness and particle size effects in HRTEM imaging of metal nanoparticles

Energy Technology Data Exchange (ETDEWEB)

House, Stephen D., E-mail: sdh46@pitt.edu [Chemical and Petroleum Engineering, and Physics, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Bonifacio, Cecile S.; Grieshaber, Ross V.; Li, Long; Zhang, Zhongfan [Chemical and Petroleum Engineering, and Physics, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Ciston, Jim [National Center of Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Stach, Eric A. [Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973 (United States); Yang, Judith C. [Chemical and Petroleum Engineering, and Physics, University of Pittsburgh, Pittsburgh, PA 15261 (United States)

2016-10-15

High-resolution transmission electron microscopy (HRTEM) examination of nanoparticles requires their placement on some manner of support – either TEM grid membranes or part of the material itself, as in many heterogeneous catalyst systems – but a systematic quantification of the practical imaging limits of this approach has been lacking. Here we address this issue through a statistical evaluation of how nanoparticle size and substrate thickness affects the ability to resolve structural features of interest in HRTEM images of metallic nanoparticles on common support membranes. The visibility of lattice fringes from crystalline Au nanoparticles on amorphous carbon and silicon supports of varying thickness was investigated with both conventional and aberration-corrected TEM. Over the 1–4 nm nanoparticle size range examined, the probability of successfully resolving lattice fringes differed significantly as a function both of nanoparticle size and support thickness. Statistical analysis was used to formulate guidelines for the selection of supports and to quantify the impact a given support would have on HRTEM imaging of crystalline structure. For nanoparticles ≥1 nm, aberration-correction was found to provide limited benefit for the purpose of visualizing lattice fringes; electron dose is more predictive of lattice fringe visibility than aberration correction. These results confirm that the ability to visualize lattice fringes is ultimately dependent on the signal-to-noise ratio of the HRTEM images, rather than the point-to-point resolving power of the microscope. This study provides a benchmark for HRTEM imaging of crystalline supported metal nanoparticles and is extensible to a wide variety of supports and nanostructures. - Highlights: • The impact of supports on imaging nanoparticle lattice structure is quantified. • Visualization probabilities given particle size and support thickness are estimated. • Aberration-correction provided limited benefit

Effects of ultrasound-related variables on sonochemically synthesized SAPO-34 nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Askari, Sima, E-mail: sima.askari@aut.ac.ir [Faculty of Chemical Engineering, Amirkabir University of Technology (Tehran Polytechnic), P.O. Box 15875-4413, Hafez Ave., Tehran (Iran, Islamic Republic of); Halladj, Rouein, E-mail: halladj@aut.ac.ir [Faculty of Chemical Engineering, Amirkabir University of Technology (Tehran Polytechnic), P.O. Box 15875-4413, Hafez Ave., Tehran (Iran, Islamic Republic of)

2013-05-01

The sonochemical method was developed to synthesize uniform SAPO-34 (silicoaluminophosphate molecular sieve) nanoparticles with high crystallinity using TEAOH as a structure-directing agent (SDA). The physicochemical characteristics of SAPO-34 products, i.e. crystallinity, particle size and shape can be controlled by varying the ultrasonic-related variable such as ultrasound power intensity, ultrasonic irradiation time, sonication temperature and geometrical characteristics of the ultrasonic device (e.g., sonotrode size). The products were characterized by XRD, SEM, TEM and BET. It is found that each of the parameters can play a significant role in acoustic cavitation, number of nuclei and the crystal growth. The experimental data establish that the crystallinity is related to ultrasonic intensity and diameter of the sonotrode, as well as sonication temperature. By increasing the ultrasonic power, duration and the sonication temperature, the mean sizes of particles decrease and the morphology of the products efficiently alters from spherical aggregates of cube type SAPO-34 particles to uniform spherical nanoparticles. - Graphical abstract: Increasing US power by increasing either US power intensity or the sonotrode diameter leads to smaller particle size and the morphology changes from spherical aggregates of cubic particles to uniform nanospheres. Highlights: • Effects of ultrasonic parameters on sonochemical synthesis of SAPO-34 nanoparticles. • The higher crystallinity by increasing ultrasonic power, duration and sonication temperature. • The morphology changes from spherical aggregates of cubic particles to uniform nanospheres. • Decreasing the particle size by increasing ultrasonic power, duration and sonication temperature.

Cryo-transmission electron microscopy of Ag nanoparticles grown on an ionic liquid substrate

KAUST Repository

Anjum, Dalaver H.

2010-07-01

We report a novel method of growing silver nanostructures by cathodic sputtering onto an ionic liquid (IL) and our visualization by transmission cryo-electron microscopy to avoid beam-induced motion of the nanoparticles. By freezing the IL suspension and controlling electron dose, we can assess properties of particle size, morphology, crystallinity, and aggregation in situ and at high detail. We observed round silver nanoparticles with a well-defined diameter of 7.0 ± 1.5 nm that are faceted with crystalline cubic structures and ∼80% of the particles have multiply twinned faults. We also applied cryo-electron tomography to investigate the structure of the nanoparticles and to directly visualize the IL wetting around them. In addition to particles, we observed nanorods that appear to have assembled from individual nanoparticles. Reexamination of the samples after 4-5 days from initial preparation showed significant changes in morphology, and potential mechanisms for this are discussed. © 2010 Materials Research Society.

DNA-guided nanoparticle assemblies

Science.gov (United States)

Gang, Oleg; Nykypanchuk, Dmytro; Maye, Mathew; van der Lelie, Daniel

2013-07-16

In some embodiments, DNA-capped nanoparticles are used to define a degree of crystalline order in assemblies thereof. In some embodiments, thermodynamically reversible and stable body-centered cubic (bcc) structures, with particles occupying <.about.10% of the unit cell, are formed. Designs and pathways amenable to the crystallization of particle assemblies are identified. In some embodiments, a plasmonic crystal is provided. In some aspects, a method for controlling the properties of particle assemblages is provided. In some embodiments a catalyst is formed from nanoparticles linked by nucleic acid sequences and forming an open crystal structure with catalytically active agents attached to the crystal on its surface or in interstices.

Synthesis of iron nanoparticles from hemoglobin and myoglobin

International Nuclear Information System (INIS)

Sayyad, Arshad S; Ajayan, Pulickel M; Balakrishnan, Kaushik; Ci, Lijie; Kabbani, Ahmad T; Vajtai, Robert

2012-01-01

Stable iron nanoparticles have been synthesized from naturally occurring and abundant Fe-containing bio-precursors, namely hemoglobin and myoglobin. The formation of stable iron nanoparticles was achieved through a one-pot, single-phase chemical reduction approach. The reduction of iron ions present in the bio-precursors was carried out at room temperature and avoids the use of harsh chemical reagents. The size distribution of the product falls into the narrow 2–5 nm range and the particles were found to be crystalline. This method can be a valuable synthetic approach for producing bio-conjugated nanoparticle systems for biological applications. (paper)

Synthesis of molybdenum oxide (MoO3) nanoparticles by hydrolysis method

International Nuclear Information System (INIS)

Alfons, M.; Manoj, V.; Karthika, M.; Karn, R.K.; John Bosco Balaguru, R.; Jeyadheepan, K.; Pandiyan, S.K.; Boomadevi, S.

2013-01-01

A pure crystalline MoO 3 nanoparticles were synthesized using Ammonium molybdate (NH 4 ) 6 Mo 7 O 24. 4H 2 O precursor and sodium carboxymethyl cellulose (CMC) capping agent. Various reaction parameters such as the additive/Mo molar ratio and temperature of the synthesis media were optimized to analyze the morphology and size of the nanoparticles. The prepared nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Scanning Electron Microscopy (FESEM). (author)

Variation in Structural and Optical Properties of Al Doped ZnO Nanoparticles Synthesized by Sol-gel Process

Directory of Open Access Journals (Sweden)

Vanaja Aravapalli

2017-04-01

Full Text Available This article focuses on analyzing structural and optical properties of Al doped ZnO (AZO synthesized with two different precursors aluminum chloride and aluminum nitrate. The nanoparticles were successfully fabricated and characterized at room temperature by sol-gel process. The objective of improving properties of ZnO nanoparticles by introducing dopants was successful with formation of nanoparticles having different crystalline sizes, optical absorption and luminescence properties. The two different sources influenced properties of ZnO. The particles with less crystalline size obtained from aluminum nitrate. Change in morphology from spherical to bar like morphology proved from SEM spectra. Presence of functional groups predicted from FTIR spectra. PL spectra proved UV emission and visible emission for AZO nanoparticles synthesized using dopant sources aluminum chloride and aluminum nitrate respectively. The obtained properties prove successful utilization of AZO nanoparticles as building materials in fabrication of optoelectronic devices.

The influence of late-stage pupal irradiation and increased irradiated: un-irradiated male ratio on mating competitiveness of the malaria mosquito Anopheles arabiensis Patton.

Science.gov (United States)

Helinski, M E H; Knols, B G J

2009-06-01

Competitiveness of released males in genetic control programmes is of critical importance. In this paper, we explored two scenarios to compensate for the loss of mating competitiveness after pupal stage irradiation in males of the malaria mosquito Anopheles arabiensis. First, competition experiments with a higher ratio of irradiated versus un-irradiated males were performed. Second, pupae were irradiated just prior to emergence and male mating competitiveness was determined. Males were irradiated in the pupal stage with a partially or fully-sterilizing dose of 70 or 120 Gy, respectively. Pupae were irradiated aged 20-26 h (young) as routinely performed, or the pupal stage was artificially prolonged by cooling and pupae were irradiated aged 42-48 h (old). Irradiated males competed at a ratio of 3:1:1 to un-irradiated males for mates in a large cage design. At the 3:1 ratio, the number of females inseminated by males irradiated with 70 Gy as young pupae was similar to the number inseminated by un-irradiated males for the majority of the replicates. At 120 Gy, significantly fewer females were inseminated by irradiated than by un-irradiated males. The irradiation of older pupae did not result in a significantly improved male mating competitiveness compared to the irradiation of young pupae. Our findings indicate that the loss of competitiveness after pupal stage irradiation can be compensated for by a threefold increase of irradiated males, but only for the partially-sterilizing dose. In addition, cooling might be a useful tool to facilitate handling processes of large numbers of mosquitoes in genetic control programmes.

Radiation quality-dependence of bystander effect in unirradiated fibroblasts is associated with TGF-β1-Smad2 pathway and miR-21 in irradiated keratinocytes

Science.gov (United States)

Yin, Xiaoming; Tian, Wenqian; Wang, Longxiao; Wang, Jingdong; Zhang, Shuyu; Cao, Jianping; Yang, Hongying

2015-01-01

Traditional radiation biology states that radiation causes damage only in cells traversed by ionizing radiation. But radiation-induced bystander effect (RIBE), which refers to the biological responses in unirradiated cells when the neighboring cells are exposed to radiation, challenged this old dogma and has become a new paradigm of this field. By nature, RIBEs are the consequences of intercellular communication between irradiated and unirradiated cells. However, there are still some important questions remain unanswered such as whether RIBE is dependent on radiation quality, what are the determining factors if so, etc. Using a transwell co-culture system, we found that HaCaT keratinocytes irradiated with α-particles but not X-rays could induce bystander micronucleus formation in unirradiated WS1 fibroblasts after co-culture. More importantly, the activation of TGF-β1-Smad2 pathway and the consistent decrease of miR-21 level in α-irradiated HaCaT cells were essential to the micronucleus induction in bystander WS1 cells. On the other hand, X-irradiation did not induce bystander effect in unirradiated WS1 cells, accompanied by lack of Smad2 activation and consistent decrease of miR-21 in X-irradiated HaCaT cells. Taken together, these results suggest that the radiation quality-dependence of bystander effect may be associated with the TGF-β1-Smad2 pathway and miR-21 in irradiated cells. PMID:26080011

Effect of hydrogen on the microstructure and electrochemical properties of Si nanoparticles synthesized by microwave plasma

Energy Technology Data Exchange (ETDEWEB)

Koo, Jeongboon; Lee, Jeongeun; Kim, Joonsoo; Jang, Boyun, E-mail: byjang@kier.re.kr

2016-09-01

We synthesized silicon (Si) nanoparticles using an atmospheric microwave plasma process, and investigated the effects of hydrogen (H{sub 2}) injection on their microstructure during the synthesis. Two nozzles were applied to inject H{sub 2} (swirling and rectilinear H{sub 2}). Our microstructural analysis indicated that the amount and method of H{sub 2} injection were critical for completion of the reaction from silicon tetrachloride (SiCl{sub 4}) to Si, as well as to obtain highly crystalline Si nanoparticles. The swirling H{sub 2} was especially critical due to its formation of vortex flow, which allowed relatively long residence time of the H-ions in plasma. The Si nanoparticles synthesized by the atmospheric plasma process had core-shell structures that consisted of crystalline Si cores with amorphous SiO{sub x} shells of 5–15 nm thickness. We also investigated the feasibility of the synthesized Si nanoparticles as anode materials in a lithium-ion battery (LIB). For the core-shell structured Si nanoparticles, we obtained the first reversible capacity of 1204 mAhg{sup −1}, and a capacity retention of 82.2% at the 50{sup th} cycle. - Highlights: • We synthesized Si nanoparticles by an atmospheric microwave plasma process. • We investigated the effects of injected H{sub 2} on the microstructures of Si nanoparticles. • Swirling H{sub 2} was critical, due to the formation of vortex flow in plasma. • The synthesized Si nanoparticles had core (crystalline Si)-shell (SiO{sub x}) structures. • The electrochemical properties depend on its core-shell structures as LIB anode.

Special Analysis for the Disposal of the INL Waste Associated with the Unirradiated Light Water Breeder Reactor (LWBR) Waste Stream at the Area 5 Radioactive Waste Management Site

Energy Technology Data Exchange (ETDEWEB)

Shott, Gregory [National Security Technologies, LLC, Las Vegas, NV (United States)

2017-03-21

This special analysis (SA) evaluates whether the Idaho National Laboratory (INL) Waste Associated with the Unirradiated Light Water Breeder Reactor (LWBR) waste stream (INEL167203QR1, Revision 0) is suitable for shallow land burial (SLB) at the Area 5 Radioactive Waste Management Site (RWMS) on the Nevada National Security Site (NNSS). Disposal of the INL Waste Associated with the Unirradiated LWBR waste meets all U.S. Department of Energy (DOE) Manual DOE M 435.1-1, “Radioactive Waste Management Manual,” Chapter IV, Section P performance objectives (DOE 1999). The INL Waste Associated with the Unirradiated LWBR waste stream is recommended for acceptance with the condition that the total uranium-233 (²³3U) inventory be limited to 2.7E13 Bq (7.2E2 Ci).

Lecithin-based wet chemical precipitation of hydroxyapatite nanoparticles.

Science.gov (United States)

Michał, Wojasiński; Ewa, Duszyńska; Tomasz, Ciach

Hydroxyapatite Ca 10 (PO 4 ) 6 (OH) 2 nanoparticles have been successfully synthesized by the wet chemical precipitation method at 60 °C in the presence of biocompatible natural surfactant-lecithin. The composition and morphology of nanoparticles of hydroxyapatite synthesized with lecithin (nHAp-PC) was studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Size distribution for nanoparticles was measured by nanoparticle tracking analysis in NanoSight system. We discuss in details influence of lecithin concentration in reaction system on nHAp-PC morphology, as well as on size distributions and suspendability of nanoparticles. Product exhibits crystalline structure and chemical composition of hydroxyapatite, with visible traces of lecithin. Difference in surfactant amounts results in changes in particles morphology and their average size.

Microwave-Assisted Synthesis of Alumina Nanoparticles Using Some Plants Extracts

Directory of Open Access Journals (Sweden)

Meisam Hasanpoor

2017-01-01

Full Text Available In present study we used five green plants for microwave assisted synthesis of Alumina nanoparticles from Aluminum nitrate. Structural characterization was studied using x-ray diffraction that showed semi- crystalline and possibly, amorphous structure. Fourier infrared spectroscopy was used to determine Al-O bond and functional groups responsible for synthesis of nanoparticles. FTIR confirmed existence of Al-O band and bio-functional groups, originated from plant extract. Morphology and size of nanoparticles were investigated using scanning electron microscopy, transmission electron microscopy and atomic force microscopy techniques. It was observed that nanoparticles have near-spherical shape. Average size of clusters of nanoparticles varied with different routes from of 60 nm to 300 nm. AFM images showed that Individual nanoparticles were less than 10 nm.

Special Analysis for the Disposal of the Idaho National Laboratory Unirradiated Light Water Breeder Reactor Rods and Pellets Waste Stream at the Area 5 Radioactive Waste Management Site, Nevada National Security Site, Nye County, Nevada

Energy Technology Data Exchange (ETDEWEB)

None

2014-08-31

The purpose of this special analysis (SA) is to determine if the Idaho National Laboratory (INL) Unirradiated Light Water Breeder Reactor (LWBR) Rods and Pellets waste stream (INEL103597TR2, Revision 2) is suitable for disposal by shallow land burial (SLB) at the Area 5 Radioactive Waste Management Site (RWMS). The INL Unirradiated LWBR Rods and Pellets waste stream consists of 24 containers with unirradiated fabricated rods and pellets composed of uranium oxide (UO2) and thorium oxide (ThO2) fuel in zirconium cladding. The INL Unirradiated LWBR Rods and Pellets waste stream requires an SA because the 229Th, 230Th, 232U, 233U, and 234U activity concentrations exceed the Nevada National Security Site (NNSS) Waste Acceptance Criteria (WAC) Action Levels.

Controlling growth density and patterning of single crystalline silicon nanowires

International Nuclear Information System (INIS)

Chang, Tung-Hao; Chang, Yu-Cheng; Liu, Fu-Ken; Chu, Tieh-Chi

2010-01-01

This study examines the usage of well-patterned Au nanoparticles (NPs) as a catalyst for one-dimensional growth of single crystalline Si nanowires (NWs) through the vapor-liquid-solid (VLS) mechanism. The study reports the fabrication of monolayer Au NPs through the self-assembly of Au NPs on a 3-aminopropyltrimethoxysilane (APTMS)-modified silicon substrate. Results indicate that the spin coating time of Au NPs plays a crucial role in determining the density of Au NPs on the surface of the silicon substrate and the later catalysis growth of Si NWs. The experiments in this study employed optical lithography to pattern Au NPs, treating them as a catalyst for Si NW growth. The patterned Si NW structures easily produced and controlled Si NW density. This approach may be useful for further studies on single crystalline Si NW-based nanodevices and their properties.

Formation of CdS nanoparticles using starch as capping agent

Energy Technology Data Exchange (ETDEWEB)

Rodriguez, P. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada-IPN, Legaria 694, Col. Irrigacion 11500, Mexico D.F. (Mexico); Munoz-Aguirre, N. [Seccion de Estudios de Posgrado e Investigacion, ESIME-IPN Azcapotzalco, Av. Las Granjas 682, Col. Santa Catarina, 02550 Mexico D.F. (Mexico); Martinez, E. San-Martin [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada-IPN, Legaria 694, Col. Irrigacion 11500, Mexico D.F. (Mexico); Seccion de Estudios de Posgrado e Investigacion, ESIME-IPN Azcapotzalco, Av. Las Granjas 682, Col. Santa Catarina, 02550 Mexico D.F. (Mexico); Departamento de Fisica, CINVESTAV-IPN, Apartado Postal 14-740, 07000 Mexico D.F. (Mexico); Gonzalez, G. [Departamento de Fisica, CINVESTAV-IPN, Apartado Postal 14-740, 07000 Mexico D.F. (Mexico)], E-mail: bato@fis.cinvestav.mx; Zelaya, O.; Mendoza, J. [Departamento de Fisica, CINVESTAV-IPN, Apartado Postal 14-740, 07000 Mexico D.F. (Mexico)

2008-11-30

CdS nanoparticles have been synthesized using starch as capping agent in aqueous solution. The morphology and crystalline structure of such samples were measured by high-resolution transmission electron microscopy and X-ray diffraction, respectively. The average grain size of the nanoparticles determined by these techniques was of the order of 5 nm. Photoluminescence of CdS nanoparticles shows a strong emission peak below to the band gap bulk semiconductor attributed to center trap states, also the broadening peak was interpreted in terms of electron-phonon interaction.

Formation of crystalline nanoparticles by iron binding to pentapeptide (Asp-His-Thr-Lys-Glu) from egg white hydrolysates.

Science.gov (United States)

Sun, Na; Cui, Pengbo; Li, Dongmei; Jin, Ziqi; Zhang, Shuyu; Lin, Songyi

2017-09-20

A novel peptide from egg white, Asp-His-Thr-Lys-Glu (DHTKE), contains specific amino acids associated with iron binding. The present study aims to better understand the molecular basis of interactions between the DHTKE peptide and iron ions. The ultraviolet-visible and fluorescence spectra indicate an interaction between the DHTKE peptide and iron ions, which leads to the formation of a DHTKE-iron complex. Notably, Asp, Glu, His, and Lys in the DHTKE peptide play crucial roles in the formation of the DHTKE-iron complex, and the iron-binding site of the DHTKE peptide corresponds primarily to the amide and carboxyl groups. The DHTKE peptide can bind iron ions in a 1 : 2 ratio with a binding constant of 1.312 × 10 5 M -1 . Moreover, the DHTKE-iron complex belongs to thermodynamically stable nanoparticles that are present in the crystalline structure, which might be attributed to peptide folding induced by iron binding. Meanwhile, the DHTKE-iron complex exhibits a relatively high iron-releasing percentage and exerts excellent solubility in the human gastrointestinal tract in vitro. This suggests a potential application of peptides containing Asp, Glu, His, or Lys residues as potential iron supplements.

Optical nonlinear absorption characteristics of Sb2Se3 nanoparticles

Science.gov (United States)

Muralikrishna, Molli; Kiran, Aditha Sai; Ravikanth, B.; Sowmendran, P.; Muthukumar, V. Sai; Venkataramaniah, Kamisetti

2014-04-01

In this work, we report for the first time, the nonlinear optical absorption properties of antimony selenide (Sb2Se3) nanoparticles synthesized through solvothermal route. X-ray diffraction results revealed the crystalline nature of the nanoparticles. Electron microscopy studies revealed that the nanoparticles are in the range of 10 - 40 nm. Elemental analysis was performed using EDAX. By employing open aperture z-scan technique, we have evaluated the effective two-photon absorption coefficient of Sb2Se3 nanoparticles to be 5e-10 m/W at 532 nm. These nanoparticles exhibit strong intensity dependent nonlinear optical absorption and hence could be considered to have optical power limiting applications in the visible range.

CEMS and XRD studies on changing shape of iron nano-particles by irradiation of Au ions of Fe-implanted Al2O3 granular layer

International Nuclear Information System (INIS)

Kato, T.; Wakabayashi, H.; Hashimoto, M.; Toriyama, T.; Taniguchi, S.; Hayashi, N.; Sakamoto, I.

2007-01-01

In order to observe an inverse Ostwald ripening of Fe nano-particles in Fe-implanted Al 2 O 3 granular layers, 3 MeV Au ions were irradiated to Fe nano-particles in these layers with doses of 0.5x and 1.5x10 16 ions/cm 2 . It was found by Conversion Electron Mossbauer Spectroscopy (CEMS) that the inverse Ostwald ripening occurred by fractions of percentages and the magnetic anisotropy of Fe nano-particles was induced to the direction of Au ion beam, i.e. perpendicular to the granular plane. The average crystallite diameters of Fe nano-particles for Au ions unirradiated and irradiated samples were measured using Scherrer's formula from FWHM of Fe (110) X-ray Diffraction (XRD) patterns obtained by 2θ and 2θ/θ methods. It was confirmed that the average crystallite diameters of Fe nano-particles in Fe-implanted Al 2 O 3 granular layers were extended by Au ions irradiation. (author)

Oxide particle size distribution from shearing irradiated and unirradiated LWR fuels in Zircaloy and stainless steel cladding: significance for risk assessment

International Nuclear Information System (INIS)

Davis, W. Jr.; West, G.A.; Stacy, R.G.

1979-01-01

Sieve fractionation was performed with oxide particles dislodged during shearing of unirradiated or irradiated fuel bundles or single rods of UO 2 or 96 to 97% ThO 2 --3 to 4% UO 2 . Analyses of these data by nonlinear least-squares techniques demonstrated that the particle size distribution is lognormal. Variables involved in the numerical analyses include lognormal median size, lognormal standard deviation, and shear cut length. Sieve-fractionation data are presented for unirradiated bundles of stainless-steel-clad or Zircaloy-2-clad UO 2 or ThO 2 --UO 2 sheared into lengths from 0.5 to 2.0 in. Data are also presented for irradiated single rods (sheared into lengths of 0.25 to 2.0 in.) of Zircaloy-2-clad UO 2 from BWRs and of Zircaloy-4-clad UO 2 from PWRs. Median particle sizes of UO 2 from shearing irradiated stainless-steel-clad fuel ranged from 103 to 182 μm; particle sizes of ThO 2 --UO 2 , under these same conditions, ranged from 137 to 202 μm. Similarly, median particle sizes of UO 2 from shearing unirradiated Zircaloy-2-clad fuel ranged from 230 to 957 μm. Irradiation levels of fuels from reactors ranged from 9,000 to 28,000 MWd/MTU. In general, particle sizes from shearing these irradiated fuels are larger than those from the unirradiated fuels. In addition, variations in particle size parameters pertaining to samples of a single vendor varied as much as those between different vendors. The fraction of fuel dislodged from the cladding is nearly proportional to the reciprocal of the shear cut length, until the cut length attains some minimum value below which all fuel is dislodged. Particles of fuel are generally elongated with a long-to-short axis ratio usually less than 3. Using parameters of the lognormal distribution deduced from experimental data, realistic estimates can be made of fractions of dislodged fuel having dimensions less than specified values

A comparative study of hydroxyapatite nanoparticles synthesized by different routes

OpenAIRE

Paz, Adrian; Guadarrama, Dainelys; López, Mónica; E. González, Jesús; Brizuela, Nayrim; Aragón, Javier

2012-01-01

In this study, bioactive hydroxyapatite nanoparticles were prepared by two different methods: wet chemical precipitation and biomimetic precipitation. The aim was to evaluate the morphology, particle-size, crystallinity and phases of the powders obtained by traditional wet chemical precipitation and the novel biomimetic precipitation using a supersaturated calcium solution. The nanoparticles were investigated by transmission electron microscopy, Fourier transform infrared spectroscopy and X-r...

Fabrication of single-crystalline plasmonic nanostructures on transparent and flexible amorphous substrates

Science.gov (United States)

Mori, Tomohiro; Mori, Takeshi; Tanaka, Yasuhiro; Suzaki, Yoshifumi; Yamaguchi, Kenzo

2017-02-01

A new experimental technique is developed for producing a high-performance single-crystalline Ag nanostructure on transparent and flexible amorphous substrates for use in plasmonic sensors and circuit components. This technique is based on the epitaxial growth of Ag on a (001)-oriented single-crystalline NaCl substrate, which is subsequently dissolved in ultrapure water to allow the Ag film to be transferred onto a wide range of different substrates. Focused ion beam milling is then used to create an Ag nanoarray structure consisting of 200 cuboid nanoparticles with a side length of 160 nm and sharp, precise edges. This array exhibits a strong signal and a sharp peak in plasmonic properties and Raman intensity when compared with a polycrystalline Ag nanoarray.

Crystalline and Crystalline International Disposal Activities

Energy Technology Data Exchange (ETDEWEB)

Viswanathan, Hari S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chu, Shaoping [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dittrich, Timothy M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hyman, Jeffrey De' Haven [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Karra, Satish [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Makedonska, Nataliia [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Reimus, Paul William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-03-06

This report presents the results of work conducted between September 2015 and July 2016 at Los Alamos National Laboratory in the crystalline disposal and crystalline international disposal work packages of the Used Fuel Disposition Campaign (UFDC) for DOE-NE’s Fuel Cycle Research and Development program. Los Alamos focused on two main activities during this period: Discrete fracture network (DFN) modeling to describe flow and radionuclide transport in complex fracture networks that are typical of crystalline rock environments, and a comprehensive interpretation of three different colloid-facilitated radionuclide transport experiments conducted in a fractured granodiorite at the Grimsel Test Site in Switzerland between 2002 and 2013. Chapter 1 presents the results of the DFN work and is divided into three main sections: (1) we show results of our recent study on the correlation between fracture size and fracture transmissivity (2) we present an analysis and visualization prototype using the concept of a flow topology graph for characterization of discrete fracture networks, and (3) we describe the Crystalline International work in support of the Swedish Task Force. Chapter 2 presents interpretation of the colloidfacilitated radionuclide transport experiments in the crystalline rock at the Grimsel Test Site.

Multiple-diffusion flame synthesis of pure anatase and carbon-coated titanium dioxide nanoparticles

KAUST Repository

Memon, Nasir

2013-09-01

A multi-element diffusion flame burner (MEDB) is useful in the study of flame synthesis of nanomaterials. Here, the growth of pure anatase and carbon-coated titanium dioxide (TiO2) using an MEDB is demonstrated. Hydrogen (H2), oxygen (O2), and argon (Ar) are utilized to establish the flame, whereas titanium tetraisopropoxide is used as the precursor for TiO2. The nanoparticles are characterized using high-resolution transmission electron microscopy, with elemental mapping (of C, O, and Ti), X-ray diffraction, Raman spectroscopy, and thermogravimetric analysis. The growth of pure anatase TiO2 nanoparticles occurs when Ar and H2 are used as the precursor carrier gas, while the growth of carbon-coated nanoparticles ensues when Ar and ethylene (C2H4) are used as the precursor carrier gas. A uniform coating of 3-5nm of carbon is observed around TiO2 particles. The growth of highly crystalline TiO2 nanoparticles is dependent on the gas flow rate of the precursor carrier and amorphous particles are observed at high flow rates. Carbon coating occurs only on crystalline nanoparticles, suggesting a possible growth mechanism of carbon-coated TiO2 nanoparticles. © 2013 The Combustion Institute.

Effects of ultrasound-related variables on sonochemically synthesized SAPO-34 nanoparticles

International Nuclear Information System (INIS)

Askari, Sima; Halladj, Rouein

2013-01-01

The sonochemical method was developed to synthesize uniform SAPO-34 (silicoaluminophosphate molecular sieve) nanoparticles with high crystallinity using TEAOH as a structure-directing agent (SDA). The physicochemical characteristics of SAPO-34 products, i.e. crystallinity, particle size and shape can be controlled by varying the ultrasonic-related variable such as ultrasound power intensity, ultrasonic irradiation time, sonication temperature and geometrical characteristics of the ultrasonic device (e.g., sonotrode size). The products were characterized by XRD, SEM, TEM and BET. It is found that each of the parameters can play a significant role in acoustic cavitation, number of nuclei and the crystal growth. The experimental data establish that the crystallinity is related to ultrasonic intensity and diameter of the sonotrode, as well as sonication temperature. By increasing the ultrasonic power, duration and the sonication temperature, the mean sizes of particles decrease and the morphology of the products efficiently alters from spherical aggregates of cube type SAPO-34 particles to uniform spherical nanoparticles. - Graphical abstract: Increasing US power by increasing either US power intensity or the sonotrode diameter leads to smaller particle size and the morphology changes from spherical aggregates of cubic particles to uniform nanospheres. Highlights: ► Effects of ultrasonic parameters on sonochemical synthesis of SAPO-34 nanoparticles. ► The higher crystallinity by increasing ultrasonic power, duration and sonication temperature. ► The morphology changes from spherical aggregates of cubic particles to uniform nanospheres. ► Decreasing the particle size by increasing ultrasonic power, duration and sonication temperature

Effect of TiO, nanoparticles on the interface in the PET-rubber composites.

Science.gov (United States)

Vladuta, Cristina; Andronic, Luminita; Duta, Anca

2010-04-01

Usually, ceramic powders (SiO2, ZnO) are used as fillers for enhancing rubber mechanical strength. Poly-ethylene terephthalate (PET)-rubber nanocomposites were prepared by compression molding using titanium oxide (TiO2) nanoparticles as low content fillers (rubber nanocomposites were studied before and after keeping the samples under UV-radiation for a week. UV-radiation has interesting potential for the photochemical modification of polymers and TiO2. The influence of UV radiation on the properties of the interface polymer-TiO2 nanoparticles was evaluated. The impact of nanoparticle aggregates on the nanometer to micrometer organization of PET-rubber composites was studied with Atomic Force Microscopy (AFM). The interface properties were explained by measuring the contact angles and surface tensions. The interactions between components of nanocomposites were investigated with Fourier Transform-Infrared (FTIR) and the effects of TiO2 nanoparticle on the interfaces and composites crystalline structure were evaluated by X-ray diffraction (XRD). The results proved that the TiO2 nanoparticles, in different weight percentages, did not alter the nanocomposites crystallinity or the average crystallites size, but improve the interface properties.

Starch-assisted synthesis and optical properties of ZnS nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Tian, Xiuying, E-mail: xiuyingt@yahoo.com; Wen, Jin; Wang, Shumei; Hu, Jilin; Li, Jing; Peng, Hongxia

2016-05-15

Highlights: • ZnS spherical nanostructure was prepared via starch-assisted method. • The crystalline lattice structure, morphologies, chemical and optical properties of ZnS nanoparticles. • The forming mechanism of ZnS nanoparticles. • ZnS spherical nano-structure can show blue emission at 460–500 nm. - Abstract: ZnS nanoparticles are fabricated via starch-assisted method. The effects of different starch amounts on structure and properties of samples are investigated, and the forming mechanism of ZnS nanoparticles is discussed. By X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible (UV–vis) spectroscopy and fluorescence (FL) spectrometer, their phases, crystalline lattice structure, morphologies, chemical and optical properties are characterized. The results show that ZnS has polycrystalline spherical structure with the mean diameter of 130 nm. Sample without starch reveals irregular aggregates with particle size distribution of 0.5–2 μm. The band gap value of ZnS is 3.97 eV. The chemical interaction exists between starch molecules and ZnS nanoparticles by hydrogen bonds. The stronger FL emission peaks of ZnS synthesized with starch, indicate a larger content of sulfur vacancies or defects than ZnS synthesized without starch.

Starch-assisted synthesis and optical properties of ZnS nanoparticles

International Nuclear Information System (INIS)

Tian, Xiuying; Wen, Jin; Wang, Shumei; Hu, Jilin; Li, Jing; Peng, Hongxia

2016-01-01

Highlights: • ZnS spherical nanostructure was prepared via starch-assisted method. • The crystalline lattice structure, morphologies, chemical and optical properties of ZnS nanoparticles. • The forming mechanism of ZnS nanoparticles. • ZnS spherical nano-structure can show blue emission at 460–500 nm. - Abstract: ZnS nanoparticles are fabricated via starch-assisted method. The effects of different starch amounts on structure and properties of samples are investigated, and the forming mechanism of ZnS nanoparticles is discussed. By X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible (UV–vis) spectroscopy and fluorescence (FL) spectrometer, their phases, crystalline lattice structure, morphologies, chemical and optical properties are characterized. The results show that ZnS has polycrystalline spherical structure with the mean diameter of 130 nm. Sample without starch reveals irregular aggregates with particle size distribution of 0.5–2 μm. The band gap value of ZnS is 3.97 eV. The chemical interaction exists between starch molecules and ZnS nanoparticles by hydrogen bonds. The stronger FL emission peaks of ZnS synthesized with starch, indicate a larger content of sulfur vacancies or defects than ZnS synthesized without starch.

Enhancement of crystallinity and magnetization in Fe3O4 nanoferrites induced by a high synthesized magnetic field

Science.gov (United States)

Ma, Xinxiu; Zhang, Zhanxian; Chen, Shijie; Lei, Wei; Xu, Yan; Lin, Jia; Luo, Xiaojing; Liu, Yongsheng

2018-05-01

A one-step hydrothermal method in different dc magnetic fields was used to prepare the Fe3O4 nanoparticles. Under the magnetic field, the average particle size decreased from 72.9 to 41.6 nm, meanwhile, the particle crystallinity is greatly improved. The magnetic field enhances its saturation magnetization and coercivity. The high magnetic field induce another magnetic structure. At room temperature, these nanoparticles exhibit superparamagnetism whose critical size (D sp) is about 26 nm. The Verwey transition is observed in the vicinity of 120 K of Fe3O4 nanoparticles. The effective magnetic anisotropy decreases with the increase of the test temperature because of the H c decreased.

Vehicles of inverted hexagonal liquid crystalline lipid phases self-assembled at room temperature

Czech Academy of Sciences Publication Activity Database

Angelov, Borislav; Angelova, A.; Garamus, V. M.; Lesieur, S.

2013-01-01

Roč. 15, 3/4 (2013), s. 211-215 ISSN 1454-4164 R&D Projects: GA ČR GAP208/10/1600 Institutional support: RVO:61389013 Keywords : liquid crystalline lipid nanoparticles * small angle X-ray scattering * cross-polarised light optical microscopy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.563, year: 2013 http://joam.inoe.ro/index.php?option=magazine&op=view&idu=3179&catid=76

Safety Analysis Report for Packaging: The unirradiated fuel shipping container USA/9853/AF

International Nuclear Information System (INIS)

1991-01-01

The HFBR Unirradiated Fuel Shipping Container was designed and fabricated at the Oak Ridge National Laboratory in 1978 for the transport of fuel for the High Flux Beam Reactor (HFBR) for Brookhaven National Laboratory. The package has been evaluated analytically, as well as the comparison to tests on similar packages, to demonstrate compliance with the applicable regulations governing packages in which radioactive and fissile materials are transported. The contents of this Safety Analysis Report for Packaging (SARP) are based on Regulatory Guide 7.9 (proposed Revision 2 - May 1986), 10 CFR Part 71, DOE Order 1540.2, DOE Order 5480.3, and 49 CFR Part 173

Palladium nanoparticles produced by CW and pulsed laser ablation in water

Energy Technology Data Exchange (ETDEWEB)

Boutinguiza, M., E-mail: mohamed@uvigo.es [Applied Physics Department, University of Vigo EEI, Lagoas-Marcosende, 9, Vigo 36310 (Spain); Comesaña, R. [Materials Engineering, Applied Mechanics and Construction Department, University of Vigo, EEI, Lagoas-Marcosende, Vigo 36310 (Spain); Lusquiños, F. [Applied Physics Department, University of Vigo EEI, Lagoas-Marcosende, 9, Vigo 36310 (Spain); Riveiro, A. [Applied Physics Department, University of Vigo EEI, Lagoas-Marcosende, 9, Vigo 36310 (Spain); Centro Universitario de la Defensa, Escuela Naval Militar, Plaza de España 2, 36920 Marín (Spain); Val, J. del; Pou, J. [Applied Physics Department, University of Vigo EEI, Lagoas-Marcosende, 9, Vigo 36310 (Spain)

2014-05-01

Palladium nanoparticles are receiving important interest due to its application as catalyst. In this work Pd nanoparticles have been obtained by ablating a Pd target submerged in de-ionized using both, pulsed as well as continuous wave (CW) laser. The influence of laser parameters involved in the formation in nanoparticles has been studied. Crystalline phases, morphology and optical properties of the obtained colloidal nanoparticles were characterized by means of transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and UV/vis absorption spectroscopy. The obtained colloidal suspensions consisted of pure Pd nanoparticles showing spherical shape with diameters ranging from few nanometers to 5–60 nm. The moderate irradiance delivered by the CW laser favours high production of uniform nanoparticles.

Morphological evolution in single-crystalline Bi2Te3 nanoparticles ...

Indian Academy of Sciences (India)

to have ZT exceeding 5 (Lin et al 2000). ... as nanoparticles (NPs) (Jiang and Zhu 2007; Cao et al. 2008a, b) ... als, semimetals, alloys and other compounds (Chen and ..... Cao Y Q, Zhao X B, Zhu T J, Zhang X B and Tu J P 2008a Appl. Phys.

Optimization and characterization of high pressure homogenization produced chemically modified starch nanoparticles.

Science.gov (United States)

Ding, Yongbo; Kan, Jianquan

2017-12-01

Chemically modified starch (RS4) nanoparticles were synthesized through homogenization and water-in-oil mini-emulsion cross-linking. Homogenization was optimized with regard to z-average diameter by using a three-factor-three-level Box-Behnken design. Homogenization pressure (X 1 ), oil/water ratio (X 2 ), and surfactant (X 3 ) were selected as independent variables, whereas z-average diameter was considered as a dependent variable. The following optimum preparation conditions were obtained to achieve the minimum average size of these nanoparticles: 50 MPa homogenization pressure, 10:1 oil/water ratio, and 2 g surfactant amount, when the predicted z-average diameter was 303.6 nm. The physicochemical properties of these nanoparticles were also determined. Dynamic light scattering experiments revealed that RS4 nanoparticles measuring a PdI of 0.380 and an average size of approximately 300 nm, which was very close to the predicted z-average diameter (303.6 nm). The absolute value of zeta potential of RS4 nanoparticles (39.7 mV) was higher than RS4 (32.4 mV), with strengthened swelling power. X-ray diffraction results revealed that homogenization induced a disruption in crystalline structure of RS4 nanoparticles led to amorphous or low-crystallinity. Results of stability analysis showed that RS4 nanosuspensions (particle size) had good stability at 30 °C over 24 h.

Crystalline and Crystalline International Disposal Activities

Energy Technology Data Exchange (ETDEWEB)

Viswanathan, Hari S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chu, Shaoping [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Reimus, Paul William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Makedonska, Nataliia [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hyman, Jeffrey De' Haven [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Karra, Satish [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dittrich, Timothy M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2015-12-21

This report presents the results of work conducted between September 2014 and July 2015 at Los Alamos National Laboratory in the crystalline disposal and crystalline international disposal work packages of the Used Fuel Disposition Campaign (UFDC) for DOE-NE’s Fuel Cycle Research and Development program.

Thermal studies on unirradiated and γ-irradiated polymer of allyl diglycol carbonate

International Nuclear Information System (INIS)

Kalsi, P.C.; Pandey, A.K.; Iyer, R.H.; Singh Mudher, K.D.

1995-01-01

The thermal decomposition of unirradiated and γ-irradiated (5.93-15.5 MRad dose range) allyl diglycol carbonate polymer (trade name, CR-39) was studied by thermogravimetry (TG) and differential thermal analysis (DTA). These studies indicate four main decomposition steps in CR-39 polymer in air. Assessment of the influence of radiation dose on the above range shows that while the 5.93 MRad γ-irradiated polymer CR-39 degrades in three steps, the 15.5 MRad γ-irradiated polymer degrades in only two steps. The kinetics of the different stages of degradation were also evaluated from the TG curves. Irradiation enhances the decomposition rate and the effect increases further with increasing radiation dose. The activation energy values calculated for all the decomposition stages decrease on irradiation

160 MeV Ni12+ ion irradiation effects on the structural, optical and electrical properties of spherical polypyrrole nanoparticles

International Nuclear Information System (INIS)

Hazarika, J.; Kumar, A.

2014-01-01

Highlights: • Upon SHI irradiation the average diameters of PPy nanoparticles increases. • Crystallinity of PPy nanoparticles increases with increasing ion fluence. • IR active vibrational bands have different cross sections for SHI irradiation. • Upon SHI irradiation optical band gap energy of PPy nanoparticles decreases. • Upon SHI irradiation thermal stability of PPy nanoparticles increases. -- Abstract: In this study we report 160 MeV Ni 12+ swift heavy ion irradiation induced enhancement in the structural, optical and electrical properties of spherical polypyrrole (PPy) nanoparticles. High resolution transmission electron microscope results show that the pristine PPy nanoparticles have an average diameter of 11 nm while upon irradiation the average diameter increases to 18 nm at the highest ion fluence of 1 × 10 12 ions/cm 2 . X-ray diffraction studies show an enhancement of crystallinity and average crystallite size of PPy nanoparticles with increasing fluence. Studies of Fourier transform infrared spectra suggest the structural modifications of different functional groups upon irradiation. It also reveals that different functional groups have different sensitivity to irradiation. The infrared active N–H vibrational band at 3695 cm −1 is more sensitive to irradiation with a formation cross-section of 5.77 × 10 −13 cm 2 and effective radius of 4.28 nm. The UV–visible absorption spectra of PPy nanoparticles show that the absorption band undergoes a red shift with increasing fluence. Moreover upon irradiation the optical band gap energy decreases and Urbach’s energy increases with fluence. Thermo-gravimetric analysis studies suggest that upon irradiation the thermal stability of PPy nanoparticles increases which may be attributed to their enhanced crystallinity. Current–voltage characteristics of PPy nanoparticles exhibit non-Ohmic, symmetric behavior which increases with fluence

Electro-catalytic properties of graphene composites containing gold or silver nanoparticles

International Nuclear Information System (INIS)

Pruneanu, Stela; Pogacean, Florina; Biris, Alexandru R.; Coros, Maria; Watanabe, Fumiya; Dervishi, Enkeleda; Biris, Alexandru S.

2013-01-01

Highlights: ► Graphene sheets with embedded gold or silver nanoparticles were prepared by RF-cCVD method. ► The crystallinity of the composite samples is less influenced by the type of metallic nanoparticles (silver or gold). ► The composite nanostructures exhibit excellent electro-catalytic properties toward carbamazepine oxidation. -- Abstract: Composite nanostructures based on few-layers graphene with encased gold or silver nanoparticles (denoted as Gr-Au and Gr-Ag, respectively) were separately prepared in a single-step synthesis by radio frequency catalytic chemical vapor deposition (RF-cCVD) over Au x /MgO and Ag x /MgO catalytic system (where x = 3 wt.%), respectively. Their morphological properties were investigated by electron microscopy techniques (TEM/HRTEM), which demonstrated that the number of graphitic layers within the sheet varied between 2 and 7. Thorough TEM analysis also indicated that gold nanoparticles had a mean size of 22 nm, while silver nanoparticles were found to be larger with a mean size of 35 nm. X-ray powder diffraction proved that the crystallinity of the Gr-Au or Gr-Ag samples is less influenced by the type of metallic nanoparticles (silver or gold) encased between the graphitic layers. The mean value of the crystalline domain perpendicular to graphene (0 0 2) crystallographic plane was determined to be approximately 2.25 nm (for Gr-Au sample) and 2.14 nm (for Gr-Ag sample), both corresponding to 6 graphitic layers. Gr-Ag and Gr-Au nanostructures were used to modify platinum substrates and subsequently employed for the electrochemical analysis of carbamazepine. A significant decrease in the electrochemical oxidation potential of carbamazepine (150 mV) was obtained with both modified electrodes. The detection limit (DL) was found to be 2.75 × 10 −5 M and 2.92 × 10 −5 M for the Pt/Gr-Ag and Pt/Gr-Au electrode, respectively

ARSENIC REMOVAL USING SOL-GEL SYNTHESIZED TITANIUM DIOXIDE NANOPARTICLES

Science.gov (United States)

In this study, the effectiveness of TiO2 nanoparticles in arsenic adsorption was examined. TiO2 particles (LS) were synthesized via sol-gel techniques and characterized for their crystallinity, surface area and pore volume. Batch adsorption studies were perf...

Formation of silk fibroin nanoparticles in water-miscible organic solvent and their characterization

Science.gov (United States)

Zhang, Yu-Qing; Shen, Wei-De; Xiang, Ru-Li; Zhuge, Lan-Jian; Gao, Wei-Jian; Wang, Wen-Bao

2007-10-01

When Silk fibre derived from Bombyx mori, a native biopolymer, was dissolved in highly concentrated neutral salts such as CaCl2, the regenerated liquid silk, a gradually degraded peptide mixture of silk fibroin, could be obtained. The silk fibroin nanoparticles were prepared rapidly from the liquid silk by using water-miscible protonic and polar aprotonic organic solvents. The nanoparticles are insoluble but well dispersed and stable in aqueous solution and are globular particles with a range of 35-125 nm in diameter by means of TEM, SEM, AFM and laser sizer. Over one half of the ɛ-amino groups exist around the protein nanoparticles by using a trinitrobenzenesulfonic acid (TNBS) method. Raman spectra shows the tyrosine residues on the surface of the globules are more exposed than those on native silk fibers. The crystalline polymorph and conformation transition of the silk nanoparticles from random-coil and α-helix form (Silk I) into anti-parallel β-sheet form (Silk II) are investigated in detail by using infrared, fluorescence and Raman spectroscopy, DSC, 13C CP-MAS NMR and electron diffraction. X-ray diffraction of the silk nanoparticles shows that the nanoparticles crystallinity is about four fifths of the native fiber. Our results indicate that the degraded peptide chains of the regenerated silk is gathered homogeneously or heterogeneously to form a looser globular structure in aqueous solution. When introduced into excessive organic solvent, the looser globules of the liquid silk are rapidly dispersed and simultaneously dehydrated internally and externally, resulting in the further chain-chain contact, arrangement of those hydrophobic domains inside the globules and final formation of crystalline silk nanoparticles with β-sheet configuration. The morphology and size of the nanoparticles are relative to the kinds, properties and even molecular structures of organic solvents, and more significantly to the looser globular substructure of the degraded silk

Formation of silk fibroin nanoparticles in water-miscible organic solvent and their characterization

International Nuclear Information System (INIS)

Zhang Yuqing; Shen Weide; Xiang Ruli; Zhuge Lanjian; Gao Weijian; Wang Wenbao

2007-01-01

When Silk fibre derived from Bombyx mori, a native biopolymer, was dissolved in highly concentrated neutral salts such as CaCl 2 , the regenerated liquid silk, a gradually degraded peptide mixture of silk fibroin, could be obtained. The silk fibroin nanoparticles were prepared rapidly from the liquid silk by using water-miscible protonic and polar aprotonic organic solvents. The nanoparticles are insoluble but well dispersed and stable in aqueous solution and are globular particles with a range of 35-125 nm in diameter by means of TEM, SEM, AFM and laser sizer. Over one half of the ε-amino groups exist around the protein nanoparticles by using a trinitrobenzenesulfonic acid (TNBS) method. Raman spectra shows the tyrosine residues on the surface of the globules are more exposed than those on native silk fibers. The crystalline polymorph and conformation transition of the silk nanoparticles from random-coil and α-helix form (Silk I) into anti-parallel β-sheet form (Silk II) are investigated in detail by using infrared, fluorescence and Raman spectroscopy, DSC, 13 C CP-MAS NMR and electron diffraction. X-ray diffraction of the silk nanoparticles shows that the nanoparticles crystallinity is about four fifths of the native fiber. Our results indicate that the degraded peptide chains of the regenerated silk is gathered homogeneously or heterogeneously to form a looser globular structure in aqueous solution. When introduced into excessive organic solvent, the looser globules of the liquid silk are rapidly dispersed and simultaneously dehydrated internally and externally, resulting in the further chain-chain contact, arrangement of those hydrophobic domains inside the globules and final formation of crystalline silk nanoparticles with β-sheet configuration. The morphology and size of the nanoparticles are relative to the kinds, properties and even molecular structures of organic solvents, and more significantly to the looser globular substructure of the degraded silk

Formation of silk fibroin nanoparticles in water-miscible organic solvent and their characterization

Energy Technology Data Exchange (ETDEWEB)

Zhang Yuqing, E-mail: yqzhang@public1.sz.js.cn; Shen Weide; Xiang Ruli [Soochow University, Silk Biotechnol. Lab., School of Life Science (China); Zhuge Lanjian; Gao Weijian; Wang Wenbao [Soochow University, Analytical Center (China)

2007-10-15

When Silk fibre derived from Bombyx mori, a native biopolymer, was dissolved in highly concentrated neutral salts such as CaCl{sub 2}, the regenerated liquid silk, a gradually degraded peptide mixture of silk fibroin, could be obtained. The silk fibroin nanoparticles were prepared rapidly from the liquid silk by using water-miscible protonic and polar aprotonic organic solvents. The nanoparticles are insoluble but well dispersed and stable in aqueous solution and are globular particles with a range of 35-125 nm in diameter by means of TEM, SEM, AFM and laser sizer. Over one half of the {epsilon}-amino groups exist around the protein nanoparticles by using a trinitrobenzenesulfonic acid (TNBS) method. Raman spectra shows the tyrosine residues on the surface of the globules are more exposed than those on native silk fibers. The crystalline polymorph and conformation transition of the silk nanoparticles from random-coil and {alpha}-helix form (Silk I) into anti-parallel {beta}-sheet form (Silk II) are investigated in detail by using infrared, fluorescence and Raman spectroscopy, DSC, {sup 13}C CP-MAS NMR and electron diffraction. X-ray diffraction of the silk nanoparticles shows that the nanoparticles crystallinity is about four fifths of the native fiber. Our results indicate that the degraded peptide chains of the regenerated silk is gathered homogeneously or heterogeneously to form a looser globular structure in aqueous solution. When introduced into excessive organic solvent, the looser globules of the liquid silk are rapidly dispersed and simultaneously dehydrated internally and externally, resulting in the further chain-chain contact, arrangement of those hydrophobic domains inside the globules and final formation of crystalline silk nanoparticles with {beta}-sheet configuration. The morphology and size of the nanoparticles are relative to the kinds, properties and even molecular structures of organic solvents, and more significantly to the looser globular

Novel Pt-Ru nanoparticles formed by vapour deposition as efficient electrocatalyst for methanol oxidation

International Nuclear Information System (INIS)

Sivakumar, Pasupathi; Ishak, Randa; Tricoli, Vincenzo

2005-01-01

Bimetallic Pt-Ru nanoparticles supported on carbon substrates have been prepared reproducibly by a simple method that utilizes commercially available metal-organic precursors at low temperature in vacuum. Particles morphology, composition and structure have been investigated using HRTEM, EDX, selected area electron diffraction (SAED) and powder XRD analysis. TEM shows that the obtained nanoparticles are homogeneously dispersed on the substrate surface and exhibit narrow size distribution, the average diameter being ca. 2 nm. Point resolved EDX analysis demonstrates co-presence of both Pt and Ru in each particle, thereby indicating that truly bimetallic nanoparticles have been obtained. Moreover, EDX performed on several areas of the sample evidences uniform particles composition. The latter can be controlled very easily and effectively by regulating the operation temperature during particles preparation. HRTEM imaging shows that the particles possess crystalline structure. Both SAED and XRD analyses indicate presence of nanoparticles exhibiting structure consistent with that of an f.c.c. Pt-Ru alloy. Besides the f.c.c. alloy, an additional crystalline phase might also be present as noticed by SAED. These nanoparticles display electrocatalytic activity with regard to methanol oxidation as evidenced by cyclic voltammetry (CV)

Luminescence enhancement of ZnO-poly(methylmethacrylate) nanocomposite films by incorporation of crystalline BaTiO_3 nanoparticles

International Nuclear Information System (INIS)

Kanamori, Tsuyoshi; Han, Yu; Nagao, Daisuke; Kamezawa, Nao; Ishii, Haruyuki; Konno, Mikio

2016-01-01

Highlights: • Dielectric barium titanate (BT) nanoparticles incorporated into luminescence films. • Luminescence intensities increased by the BT nanoparticle incorporation. • Incorporation of highly dielectric nanoparticles effective for luminescence enhancement. - Abstract: Incorporation of highly dielectric nanoparticles into luminescent ZnO-polymethylmethacrylate (PMMA) nanocomposite films was undertaken to examine the effect of nanoparticle incorporation on luminescence intensity of the nanocomposite films. ZnO nanoparticles were prepared as inorganic phosphors by a precipitation method. The ZnO nanoparticles were then surface-modified with 3-methacryloxypropyltrimethoxysilane (MPTMS) to be used for fabrication of the ZnO-PMMA nanocomposite film. Barium titanate (BT) nanoparticles were synthesized with a sol-gel method as the highly dielectric nanoparticles, which were also surface-modified with the MPTMS for the incorporation into the nanocomposite films. Luminescence intensity of the nanocomposite films was successfully increased by the nanoparticle incorporation up to a BT content around 15 vol%. The luminescence intensity higher than that measured for the nanocomposite films incorporating SiO_2 nanoparticles indicated that the incorporation of highly dielectric nanoparticles was an effective approach to enhance the luminescence of ZnO nanoparticles in the polymer thin films.

Programming Nanoparticles in Multiscale: Optically Modulated Assembly and Phase Switching of Silicon Nanoparticle Array.

Science.gov (United States)

Wang, Letian; Rho, Yoonsoo; Shou, Wan; Hong, Sukjoon; Kato, Kimihiko; Eliceiri, Matthew; Shi, Meng; Grigoropoulos, Costas P; Pan, Heng; Carraro, Carlo; Qi, Dongfeng

2018-03-27

Manipulating and tuning nanoparticles by means of optical field interactions is of key interest for nanoscience and applications in electronics and photonics. We report scalable, direct, and optically modulated writing of nanoparticle patterns (size, number, and location) of high precision using a pulsed nanosecond laser. The complex nanoparticle arrangement is modulated by the laser pulse energy and polarization with the particle size ranging from 60 to 330 nm. Furthermore, we report fast cooling-rate induced phase switching of crystalline Si nanoparticles to the amorphous state. Such phase switching has usually been observed in compound phase change materials like GeSbTe. The ensuing modification of atomic structure leads to dielectric constant switching. Based on these effects, a multiscale laser-assisted method of fabricating Mie resonator arrays is proposed. The number of Mie resonators, as well as the resonance peaks and dielectric constants of selected resonators, can be programmed. The programmable light-matter interaction serves as a mechanism to fabricate optical metasurfaces, structural color, and multidimensional optical storage devices.

160 MeV Ni{sup 12+} ion irradiation effects on the structural, optical and electrical properties of spherical polypyrrole nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Hazarika, J.; Kumar, A., E-mail: ask@tezu.ernet.in

2014-01-01

Highlights: • Upon SHI irradiation the average diameters of PPy nanoparticles increases. • Crystallinity of PPy nanoparticles increases with increasing ion fluence. • IR active vibrational bands have different cross sections for SHI irradiation. • Upon SHI irradiation optical band gap energy of PPy nanoparticles decreases. • Upon SHI irradiation thermal stability of PPy nanoparticles increases. -- Abstract: In this study we report 160 MeV Ni{sup 12+} swift heavy ion irradiation induced enhancement in the structural, optical and electrical properties of spherical polypyrrole (PPy) nanoparticles. High resolution transmission electron microscope results show that the pristine PPy nanoparticles have an average diameter of 11 nm while upon irradiation the average diameter increases to 18 nm at the highest ion fluence of 1 × 10{sup 12} ions/cm{sup 2}. X-ray diffraction studies show an enhancement of crystallinity and average crystallite size of PPy nanoparticles with increasing fluence. Studies of Fourier transform infrared spectra suggest the structural modifications of different functional groups upon irradiation. It also reveals that different functional groups have different sensitivity to irradiation. The infrared active N–H vibrational band at 3695 cm{sup −1} is more sensitive to irradiation with a formation cross-section of 5.77 × 10{sup −13} cm{sup 2} and effective radius of 4.28 nm. The UV–visible absorption spectra of PPy nanoparticles show that the absorption band undergoes a red shift with increasing fluence. Moreover upon irradiation the optical band gap energy decreases and Urbach’s energy increases with fluence. Thermo-gravimetric analysis studies suggest that upon irradiation the thermal stability of PPy nanoparticles increases which may be attributed to their enhanced crystallinity. Current–voltage characteristics of PPy nanoparticles exhibit non-Ohmic, symmetric behavior which increases with fluence.

Trapping shape-controlled nanoparticle nucleation and growth stages via continuous-flow chemistry.

Science.gov (United States)

LaGrow, Alec P; Besong, Tabot M D; AlYami, Noktan M; Katsiev, Khabiboulakh; Anjum, Dalaver H; Abdelkader, Ahmed; Costa, Pedro M F J; Burlakov, Victor M; Goriely, Alain; Bakr, Osman M

2017-02-21

Continuous flow chemistry is used to trap the nucleation and growth stages of platinum-nickel nano-octahedra with second time resolution and high throughputs to probe their properties ex situ. The growth starts from poorly crystalline particles (nucleation) at 5 seconds, to crystalline 1.5 nm particles bounded by the {111}-facets at 7.5 seconds, followed by truncation and further growth to octahedral nanoparticles at 20 seconds.

Trapping shape-controlled nanoparticle nucleation and growth stages via continuous-flow chemistry

KAUST Repository

LaGrow, Alec P.; Besong, Tabot M.D.; AlYami, Noktan; Katsiev, Khabiboulakh; Anjum, Dalaver H.; Abdelkader, Ahmed; Da Costa, Pedro M. F. J.; Burlakov, Victor M.; Goriely, Alain; Bakr, Osman

2017-01-01

Continuous flow chemistry is used to trap the nucleation and growth stages of platinum-nickel nano-octahedra with second time resolution and high throughputs to probe their properties ex situ. The growth starts from poorly crystalline particles (nucleation) at 5 seconds, to crystalline 1.5 nm particles bounded by the {111}-facets at 7.5 seconds, followed by truncation and further growth to octahedral nanoparticles at 20 seconds.

Trapping shape-controlled nanoparticle nucleation and growth stages via continuous-flow chemistry

KAUST Repository

LaGrow, Alec P.

2017-02-06

Continuous flow chemistry is used to trap the nucleation and growth stages of platinum-nickel nano-octahedra with second time resolution and high throughputs to probe their properties ex situ. The growth starts from poorly crystalline particles (nucleation) at 5 seconds, to crystalline 1.5 nm particles bounded by the {111}-facets at 7.5 seconds, followed by truncation and further growth to octahedral nanoparticles at 20 seconds.

Structure and nanotribology of thermally deposited gold nanoparticles on graphite

Energy Technology Data Exchange (ETDEWEB)

Cihan, Ebru [UNAM - Institute of Materials Science and Nanotechnology, Bilkent University, Ankara 06800 (Turkey); Özoğul, Alper [Department of Mechanical Engineering, Bilkent University, Ankara 06800 (Turkey); Baykara, Mehmet Z., E-mail: mehmet.baykara@bilkent.edu.tr [UNAM - Institute of Materials Science and Nanotechnology, Bilkent University, Ankara 06800 (Turkey); Department of Mechanical Engineering, Bilkent University, Ankara 06800 (Turkey)

2015-11-01

Graphical abstract: - Highlights: • Structure and tribology of thermally deposited AuNPs on HOPG have been studied. • Well-faceted, hexagonal AuNPs are formed on HOPG upon post-deposition annealing. • The crystalline character of the AuNPs is confirmed via TEM measurements. • AFM measurements reveal a “2/3” power law dependence of friction on load on AuNPs. • Friction forces at AuNP edges evolve linearly with increasing height and load. - Abstract: We present experiments involving the structural and frictional characterization of gold nanoparticles (AuNP) thermally deposited on highly oriented pyrolytic graphite (HOPG). The effect of thermal deposition amount, as well as post-deposition annealing on the morphology and distribution of gold on HOPG is studied via scanning electron microscopy (SEM) measurements, while transmission electron microscopy (TEM) is utilized to confirm the crystalline character of the nanoparticles. Lateral force measurements conducted via atomic force microscopy (AFM) under ambient conditions are employed to investigate the nanotribological properties of the gold nanoparticles as a function of normal load. Finally, the increase in lateral force experienced at the edges of the nanoparticles is studied as a function of normal load, as well as nanoparticle height. As a whole, our results constitute a comprehensive structural and frictional characterization of the AuNP/HOPG material system, forming the basis for nanotribology experiments involving the lateral manipulation of thermally deposited AuNPs on HOPG via AFM under ambient conditions.

Structure and nanotribology of thermally deposited gold nanoparticles on graphite

International Nuclear Information System (INIS)

Cihan, Ebru; Özoğul, Alper; Baykara, Mehmet Z.

2015-01-01

Graphical abstract: - Highlights: • Structure and tribology of thermally deposited AuNPs on HOPG have been studied. • Well-faceted, hexagonal AuNPs are formed on HOPG upon post-deposition annealing. • The crystalline character of the AuNPs is confirmed via TEM measurements. • AFM measurements reveal a “2/3” power law dependence of friction on load on AuNPs. • Friction forces at AuNP edges evolve linearly with increasing height and load. - Abstract: We present experiments involving the structural and frictional characterization of gold nanoparticles (AuNP) thermally deposited on highly oriented pyrolytic graphite (HOPG). The effect of thermal deposition amount, as well as post-deposition annealing on the morphology and distribution of gold on HOPG is studied via scanning electron microscopy (SEM) measurements, while transmission electron microscopy (TEM) is utilized to confirm the crystalline character of the nanoparticles. Lateral force measurements conducted via atomic force microscopy (AFM) under ambient conditions are employed to investigate the nanotribological properties of the gold nanoparticles as a function of normal load. Finally, the increase in lateral force experienced at the edges of the nanoparticles is studied as a function of normal load, as well as nanoparticle height. As a whole, our results constitute a comprehensive structural and frictional characterization of the AuNP/HOPG material system, forming the basis for nanotribology experiments involving the lateral manipulation of thermally deposited AuNPs on HOPG via AFM under ambient conditions.

Nanoparticles migration in fractured rocks and affects on contaminant migration

Science.gov (United States)

Missana, Tiziana; Garcia-Gutierrez, Miguel; Alonso, Ursula

2014-05-01

In previous studies, the transport behavior of artificial (gold and latex) and natural (smectite clay) colloids, within a planar fracture in crystalline rock, was analyzed. In order to better understand the effects of colloid size, shape and surface charge on nanoparticle migration and especially on filtration processes on natural rock surfaces, different clay colloids and oxide nanoparticles were selected and their transport studied as a function of the residence time. In all the cases, (a fraction of) the nanoparticles travelled in the fracture as fast as or faster than water (with a retardation factor, Rf ≤ 1) and the observed Rf, was related to the Taylor dispersion coefficient, accounting for colloid size, water velocity and fracture width. However, under most of the cases, in contrast to the behavior of a conservative tracer, colloids recovery was much lower than 100 %. Differences in recovery between different nanoparticles, under similar residence times, were analyzed. In order to evaluate the possible consequences, on contaminant migration, of the presence of nanoparticles in the system, transport tests were carried out with both colloids and sorbing radionuclides. The overall capacity for colloids of enhancing radionuclide migration in crystalline rock fractures is discussed. Acknowledgments: The research leading to these results received funding from EU FP7/2007-2011 grant agreement Nº 295487 (BELBAR, Bentonite Erosion: effects on the Long term performance of the engineered Barrier and Radionuclide Transport) and by the Spanish Government under the project NANOBAG (CTM2011-2797).

Structural and magnetic properties of single-crystalline Co-doped barium titanate nanoparticles

International Nuclear Information System (INIS)

Liu Hongxue; Cao Baobao; O'Connor, Charles J.

2010-01-01

Undoped and Co-doped BaTiO 3 nanoparticles were synthesized by a one-step sol-precipitation method. For all the samples, X-ray diffraction showed characteristic diffraction lines for BaTiO 3 without the indication of secondary phases. High-resolution transition electron microscopy images showed that BaTiO 3 nanoparticles exhibit the nature of single-crystal. Magnetometry revealed that all the Co-doped BaTiO 3 samples show paramagnetic behaviors and Co ions in BaTiO 3 are present as isolated paramagnetic centers. This is contrasted to several reported cases of ferromagnetism in Co-doped BaTiO 3 .

Nano-sized crystalline drug production by milling technology.

Science.gov (United States)

Moribe, Kunikazu; Ueda, Keisuke; Limwikrant, Waree; Higashi, Kenjirou; Yamamoto, Keiji

2013-01-01

Nano-formulation of poorly water-soluble drugs has been developed to enhance drug dissolution. In this review, we introduce nano-milling technology described in recently published papers. Factors affecting the size of drug crystals are compared based on the preparation methods and drug and excipient types. A top-down approach using the comminution process is a method conventionally used to prepare crystalline drug nanoparticles. Wet milling using media is well studied and several wet-milled drug formulations are now on the market. Several trials on drug nanosuspension preparation using different apparatuses, materials, and conditions have been reported. Wet milling using a high-pressure homogenizer is another alternative to preparing production-scale drug nanosuspensions. Dry milling is a simple method of preparing a solid-state drug nano-formulation. The effect of size on the dissolution of a drug from nanoparticles is an area of fundamental research, but it is sometimes incorrectly evaluated. Here, we discuss evaluation procedures and the associated problems. Lastly, the importance of quality control, process optimization, and physicochemical characterization are briefly discussed.

Gold nanoparticles in plastic columnar discotic liquid crystalline material

Energy Technology Data Exchange (ETDEWEB)

Mishra, Mukesh, E-mail: mukeshphysics927@gmail.com [Center of Material Sciences, Institute of Interdisciplinary Studies, University of Allahabad, Allahabad 211002 (India); Kumar, Sandeep [Raman Research Institute, C.V. Raman Avenue, Sadashivanagar, Bangalore 560080 (India); Dhar, Ravindra, E-mail: dr.ravindra.dhar@gmail.com [Center of Material Sciences, Institute of Interdisciplinary Studies, University of Allahabad, Allahabad 211002 (India)

2016-05-10

Highlights: • Dispersion of Gold nanoparticles in a discotic liquid crystal has been studied. • σ{sub i} increases by seven orders of magnitude in the case of 1.2 wt% GNPs composites. • X-ray scattering results revel that a decrement in the core–core separation. • Study suggests that dispersion at low concentrations is uniform. • Band gap has decreased due to dispersion of GNPs in HAT4. - Abstract: We have studied the effect of gold nanoparticles (GNPs) on the thermodynamical, optical and dielectrical parameters of a discotic liquid crystal (DLC) namely hexabutyloxytriphenylene (HAT4). It has been observed that with the increase of GNPs concentration in DLC, composites shows two different regions. In the first regions i.e. low concentrations (<1 wt%), columnar hexagonal-isotropic (Col{sub hp}-I{sub L}) transition temperature and enthalpy (ΔH) decrease rapidly while in the second region i.e. higher concentrations (>1 wt%) Col{sub hp}-I{sub L} transition temperature and ΔH are approximately constant. It has been observed that, in the case of composites having 0.2 and 0.6 wt% of GNPs, conductivity has enhanced but it is poor as compared to the composite having 1.2 wt% of GNPs. For 1.2 wt% of GNPs, conductivity has increased by seven orders of magnitude as compared to the DLC. Optical study suggests that band gap of nanocomposites has decreased due to dispersion of GNPs.

Surface modifications caused by a swift heavy ion irradiation on crystalline p-type gallium antimonide

Science.gov (United States)

Jadhav, Vidya

2015-09-01

Surface modifications caused by a swift heavy ion irradiation on crystalline p-type gallium antimonide crystal have been reported. Single crystal, 1 0 0> orientations and ∼500 μm thick p-type GaSb samples with carrier concentration of 3.30 × 1017 cm-3 were irradiated at 100 MeV Fe7+ ions. We have used 15UD Pelletron facilities at IUAC with varying fluences of 5 × 1010-1 × 1014 ions cm-2. The effects of irradiation on these samples have been investigated using, spectroscopic ellipsometry, atomic force microscopy and ultraviolet-visible-NIR spectroscopy techniques. Ellipsometry parameters, psi (Ψ) and delta (Δ) for the unirradiated sample and samples irradiated with different fluences were recorded. The data were fit to a three phase model to determine the refractive index and extinction coefficient. The refractive index and extinction coefficient for various fluences in ultraviolet, visible, and infrared, regimes were evaluated. Atomic force microscopy has been used to study these surface modifications. In order to have more statistical information about the surface, we have plotted the height structure histogram for all the samples. For unirradiated sample, we observed the Gaussian fitting. This result indicates the more ordered height structure symmetry. Whereas for the sample irradiated with the fluence of 1 × 1013, 5 × 1013 and 1 × 1014 ions cm-2, we observed the scattered data. The width of the histogram for samples irradiated up to the fluence of 1 × 1013 ion cm-2 was found to be almost same however it decreased at higher fluence. UV reflectance spectra of the sample irradiated with increasing fluences exhibit three peaks at 292, 500 and 617 nm represent the high energy GaSb; E1, E1 + Δ and E2 band gaps in all irradiated samples.

Understanding the growth of micro and nano-crystalline AlN by thermal plasma process

Science.gov (United States)

Kanhe, Nilesh S.; Nawale, Ashok B.; Gawade, Rupesh L.; Puranik, Vedavati G.; Bhoraskar, Sudha V.; Das, Asoka K.; Mathe, Vikas L.

2012-01-01

We report the studies related to the growth of crystalline AlN in a DC thermal plasma reactor, operated by a transferred arc plasma torch. The reactor is capable of producing the nanoparticles of Al and AlN depending on the composition of the reacting gas. Al and AlN micro crystals are formed at the anode placed on the graphite and nano crystalline Al and AlN gets deposited on the inner surface of the plasma reactor. X-ray diffraction, Raman spectroscopy analysis, single crystal X-ray diffraction and TGA-DTA techniques are used to infer the purity of post process crystals as a hexagonal AlN. The average particle size using SEM was found to be around 30 μm. The morphology of nanoparticles of Al and AlN, nucleated by gas phase condensation in a homogeneous medium were studied by transmission electron microscopy analysis. The particle ranged in size between 15 and 80 nm in diameter. The possible growth mechanism of crystalline AlN at the anode has been explained on the basis of non-equilibrium processes in the core of the plasma and steep temperature gradient near its periphery. The gas phase species of AlN and various constituent were computed using Murphy code based on minimization of free energy. The process provides 50% yield of microcrystalline AlN and remaining of Al at anode and that of nanocrystalline h-AlN and c-Al collected from the walls of the chamber is about 33% and 67%, respectively.

Composite Polymer Electrolytes: Nanoparticles Affect Structure and Properties

Directory of Open Access Journals (Sweden)

Wei Wang

2016-11-01

Full Text Available Composite polymer electrolytes (CPEs can significantly improve the performance in electrochemical devices such as lithium-ion batteries. This review summarizes property/performance relationships in the case where nanoparticles are introduced to polymer electrolytes. It is the aim of this review to provide a knowledge network that elucidates the role of nano-additives in the CPEs. Central to the discussion is the impact on the CPE performance of properties such as crystalline/amorphous structure, dielectric behavior, and interactions within the CPE. The amorphous domains of semi-crystalline polymer facilitate the ion transport, while an enhanced mobility of polymer chains contributes to high ionic conductivity. Dielectric properties reflect the relaxation behavior of polymer chains as an important factor in ion conduction. Further, the dielectric constant (ε determines the capability of the polymer to dissolve salt. The atom/ion/nanoparticle interactions within CPEs suggest ways to enhance the CPE conductivity by generating more free lithium ions. Certain properties can be improved simultaneously by nanoparticle addition in order to optimize the overall performance of the electrolyte. The effects of nano-additives on thermal and mechanical properties of CPEs are also presented in order to evaluate the electrolyte competence for lithium-ion battery applications.

Effect of silver doping on the elastic properties of CdS nanoparticles

Science.gov (United States)

Dey, P. C.; Das, R.

2018-05-01

CdS and Ag doped CdS (CdS/Ag) nanoparticles have been prepared via chemical method from a Cadmium acetate precursor and Thiourea. The synthesized CdS and CdS/Ag nanoparticles have been characterized by the X-ray Diffraction and High Resolution Transmission Electron Microscope. Here, these nanoparticles have been synthesized at room temperature and all the characterization have also been done at room temperature only. The XRD results reveal that the products are crystalline with cubic zinc blende structure. HRTEM images show that the prepared nanoparticles are nearly spherical in shape. Williamson-Hall method and Size-Strain Plot (SSP) have been used to study the individual contribution of crystalline sizes and lattice strain on the peak broadening of the CdS and CdS/Ag nanoparticles. The different modified model of Williamson-Hall method such as, uniform deformation model, uniform stress deformation model and uniform energy density deformation model and SSP method have been used to calculate the different physical parameter such as lattice strain, stress and energy density for all diffraction peaks of the XRD, corresponding to the CdS and silver doped CdS (CdS/Ag). The obtained results reveal that the average particle size of the prepared CdS and CdS/Ag nanoparticles estimated from the HRTEM images, Williamson-Hall analysis and SSP method are highly correlated with each other. Further, all these result confirms that doping of Ag significantly affects the elastic properties of CdS.

Crystalline Silica Primer

Science.gov (United States)

,

1992-01-01

Crystalline silica is the scientific name for a group of minerals composed of silicon and oxygen. The term crystalline refers to the fact that the oxygen and silicon atoms are arranged in a threedimensional repeating pattern. This group of minerals has shaped human history since the beginning of civilization. From the sand used for making glass to the piezoelectric quartz crystals used in advanced communication systems, crystalline silica has been a part of our technological development. Crystalline silica's pervasiveness in our technology is matched only by its abundance in nature. It's found in samples from every geologic era and from every location around the globe. Scientists have known for decades that prolonged and excessive exposure to crystalline silica dust in mining environments can cause silicosis, a noncancerous lung disease. During the 1980's, studies were conducted that suggested that crystalline silica also was a carcinogen. As a result of these findings, crystalline silica has been regulated under the Occupational Safety and Health Administration's (OSHA) Hazard Communication Standard (HCS). Under HCS, OSHAregulated businesses that use materials containing 0.1% or more crystalline silica must follow Federal guidelines concerning hazard communication and worker training. Although the HCS does not require that samples be analyzed for crystalline silica, mineral suppliers or OSHAregulated

Synthesis of CdSe nanoparticles and their effect on the antioxidant activity of Spirulina platensis and Porphyridium cruentum cells

International Nuclear Information System (INIS)

Rudic, V.; Cepoi, L.; Rudi, L.; Chiriac, T.; Nicorici, A.; Todosiciuc, A.; Gutsul, T.

2011-01-01

Single-crystalline cadmium selenide nanoparticles were obtained using high-temperature solution phase synthesis (HTSPS) synthesis. X-Ray powder diffraction and transmission electron microscopy were used to confirm the crystallinity and morphology of the resulting nanoparticles. To study the action of CdSe on antioxidant activity, we selected two biotechnological important strains of microalgae: cyanobacteria Spirulina platensis and red microalgae Porphyridium cruentum. In the case of Porphyridium cruentum, the obtained results demonstrated an increase in the productivity. For Spirulina platensis, the presence of the compound in the cultivating medium decreased the productivity of cyanobacteria.

Light trapping in a-Si/c-Si heterojunction solar cells by embedded ITO nanoparticles at rear surface

Science.gov (United States)

Dhar, Sukanta; Mandal, Sourav; Mitra, Suchismita; Ghosh, Hemanta; Mukherjee, Sampad; Banerjee, Chandan; Saha, Hiranmoy; Barua, A. K.

2017-12-01

The advantages of the amorphous silicon (a-Si)/crystalline silicon (c-Si) hetero junction technology are low temperature (oxide (ITO) nanoparticles embedded in amorphous silicon material at the rear side of the crystalline wafer. The nanoparticles were embedded in silicon to have higher scattering efficiency, as has been established by simulation studies. It has been shown that significant photocurrent enhancements (32.8 mA cm-2 to 35.1 mA cm-2) are achieved because of high scattering and coupling efficiency of the embedded nanoparticles into the silicon device, leading to an increase in efficiency from 13.74% to 15.22%. In addition, we have observed a small increase in open circuit voltage. This may be due to the surface passivation during the ITO nanoparticle formation with hydrogen plasma treatment. We also support our experimental results by simulation, with the help of a commercial finite-difference time-domain (FDTD) software solution.

Recent advances in cryo-TEM imaging of soft lipid nanoparticles

DEFF Research Database (Denmark)

Helvig, Shen Yu; Mat Azmi, Intan Diana Binti; Moghimi, Seyed Moien

2015-01-01

Cryo-transmission electron microscopy (Cryo-TEM), and its technological variations thereof, have become a powerful tool for detailed morphological characterization and 3D tomography of soft lipid and polymeric nanoparticles as well as biological materials such as viruses and DNA without chemical...... fixation. Here, we review and discuss recent advances in Cryo-TEM analysis of lipid-based drug nanocarriers with particular emphasis on morphological and internal nanostructure characterization of lyotropic liquid crystalline nanoparticles such as cubosomes and hexosomes....

Damage and failure of unirradiated and irradiated fuel rods tested under film boiling conditions

International Nuclear Information System (INIS)

Mehner, A.S.; Hobbins, R.R.; Seiffert, S.L.; MacDonald, P.E.; McCardell, R.K.

1979-01-01

Power-cooling-mismatch experiments are being conducted as part of the Thermal Fuels Behavior Program in the Power Burst Facility at the Idaho National Engineering Laboratory to evaluate the behavior of unirradiated and previously irradiated light water reactor fuel rods tested under stable film boiling conditions. The observed damage that occurs to the fuel rod cladding and the fuel as a result of film boiling operation is reported. Analyses performed as a part of the study on the effects of operating failed fuel rods in film boiling, and rod failure mechanisms due to cladding embrittlement and cladding melting upon being contacted by molten fuel are summarized

Magnetite and cobalt ferrite nanoparticles used as seeds for acid mine drainage treatment

Energy Technology Data Exchange (ETDEWEB)

Kefeni, Kebede K., E-mail: kkefeni@gmail.com; Mamba, Bhekie B.; Msagati, Titus A.M.

2017-07-05

Highlights: • Presence of α-Fe{sub 2}O{sub 3} and Fe{sub 3}O{sub 4} in AMD resulted in formation of crystalline ferrite. • Increasing settling time improved removal of Mg, Ca, Mn and Na from AMD. • Mixtures of ferrite nanoparticles were produced from AMD. • Formations of crystalline ferrite were more favored in the presence of heat. - Abstract: In this study, magnetite and cobalt ferrite nanoparticles were used as seeds for acid mine drainage (AMD) treatment at pH of 7.05 ± 0.35. Duplicate samples of AMD, one without heating and another with heating at 60 °C was treated under continuous stirring for 1 h. The filtrate analysis results from ICP-OES have shown complete removal of Al, Mg, and Mn, while for Fe, Ni and Zn over 90% removals were recorded. Particularly, settling time has significant effect on the removal of Mg, Ca and Na. The results from SQUID have shown superparamagnetic properties of the synthesised magnetic nanoparticles and ferrite sludge. The recovered nanoparticles from AMD are economically important and reduce the cost of waste disposal.

Control surface wettability with nanoparticles from phase-change materials

NARCIS (Netherlands)

Ten Brink, G. H.; van het Hof, P. J.; Chen, B.; Sedighi, M.; Kooi, B. J.; Palasantzas, G.

2016-01-01

The wetting state of surfaces can be controlled physically from the highly hydrophobic to hydrophilic states using the amorphous-to-crystalline phase transition of Ge2Sb2Te5 (GST) nanoparticles as surfactant. Indeed, contact angle measurements show that by increasing the surface coverage of the

Structural transformations of mechanically induced top-down approach BaFe12O19 nanoparticles synthesized from high crystallinity bulk materials

International Nuclear Information System (INIS)

Low, Zhi Huang; Chen, Soo Kien; Ismail, Ismayadi; Tan, Kim Song; Liew, J.Y.C.

2017-01-01

In this work, a top-down approach was applied to high crystallinity BaFe 12 O 19 bulks, breaking them into smaller nanoparticles by mechanochemical route. The effects of milling time, reaction mechanisms and structural information were investigated. Interestingly, three distinct stages of the mechanochemical mechanism were observed. The XRD results indicated that the BaFe 12 O 19 phase existed even though the mechanical energy had induced the formation of an amorphous phase in the material. The average crystallite size decreased during the first stage and the intermediate stage, and increased during the final stage of the mechanical alloying. A Rietveld refinement analysis suggested the deformation of a mechanically-triggered polyhedral in the magnetoplumbite structure. FESEM micrographs indicated that fragmentation predominated during the first and intermediate stages, until a steady equilibrium state was achieved at in the final stage, where a narrow particle size distribution was observed. HRTEM micrographs suggested the formation of a non-uniform nanostructure shell surrounding the ordered core materials at the edge-interface region. The thickness of the amorphous surface layer extended up to 12 nm during the first and intermediate stages, and diminished to approximately 3 nm after 20 h milling. VSM results showed a mixture of ferromagnetic, superparamagnetic, and paramagnetic behaviours. However, different magnetic behaviours predominated at different milling time, which strongly related to the defects, distorted polyhedra, and non-equilibrium amorphous layers of the material. - Highlights: • Nanoparticles of BaFe 12 O 19 are successfully prepared. • Morphological and structural properties rely on mechanochemical mechanism. • Three stages of mechanochemical mechanism was observed. • Core shell structures (3–12 nm) was found during by extending the milling time. • Magnetic properties were strongly related with the mechanically induced defects.

Lamellar crystalline self-assembly behaviour and solid lipid nanoparticles of a palmityl prodrug analogue of Capecitabine—A chemotherapy agent

Energy Technology Data Exchange (ETDEWEB)

Gong, Xiaojuan; Moghaddam, Minoo J.; Sagnella, Sharon M.; Conn, Charlotte E.; Danon, Stephen J.; Waddington, Lynne J.; Drummond, Calum J. [CSIRO/MSE

2014-09-24

An amphiphile prodrug, 5'-deoxy-5-fluoro-N⁴-(palmityloxycarbonyl) cytidine or 5'-deoxy-5-fluoro-N⁴-(hexadecanaloxycarbonyl) cytidine (5-FCPal), consisting of the same head group as the commercially available chemotherapeutic agent Capecitabine, linked to a palmityl hydrocarbon chain via a carbamate bond is reported. Thermal analysis of this prodrug indicates that it melts at ~115 °C followed quickly by degradation beginning at ~120 °C. The neat solid 5-FCPal amphiphile acquires a lamellar crystalline arrangement with a d-spacing of 28.6 ± 0.3 Å, indicating interdigitation of the hydrocarbon chains. Under aqueous conditions, solid 5-FCPal is non-swelling and no lyotropic liquid crystalline phase formation is observed. In order to assess the in vitro toxicity and in vivo efficacy in colloidal form, solid lipid nanoparticles (SLNs) with an average size of ~700 nm were produced via high pressure homogenization. The in vitro toxicity of the 5-FCPal SLNs against several different cancer and normal cell types was assessed over a 48 h period, and IC₅₀ values were comparable to those observed for Capecitabine. The in vivo efficacy of the 5-FCPal SLNs was then assessed against the highly aggressive mouse 4T1 breast cancer model. To do so, the prodrug SLNs were administered orally at 3 different dosages (0.1, 0.25, 0.5 mmol/mouse/day) and compared to Capecitabine delivered at the same dosages. After 21 days of receiving the treatments, the 0.5 mmol dose of 5-FCPal exhibited the smallest average tumour volume. Since 5-FCPal is activated in a similar manner to Capecitabine via a 3 step enzymatic pathway with the final step occurring preferentially at the tumour site, formulation of the prodrug into SLNs combines the advantage of selective, localized activation with the sustained release properties of nanostructured amphiphile self-assembly and multiple payload materials thereby potentially creating a more effective anticancer agent.

The Effect of Process Parameters on the Synthesis of Ti and TiO2 Nanoparticles Producted by Electromagnetic Levitational Gas Condensation

Directory of Open Access Journals (Sweden)

Maryam Moazeni

2012-10-01

Full Text Available The nanoparticles of Ti and TiO2 have attracted extensive research interest because of their diverse applications in, for instance, catalysis, energy conversion, pigment and cosmetic manufacturing and biomedical engineering. Through this project, a one-step bulk synthesis method of electromagnetic levitational gas condensation (ELGC was utilized for the synthesis of monodispersed and crystalline Ti and TiO2 nanoparticles. Within the process, the Ti vapours ascending from the high temperature levitated droplet were condensed by an argon gas stream under atmospheric pressure. The TiO2 nanoparticles were produced by simultaneous injection of argon and oxygen into the reactor. The effects of flow rate of the condensing and oxidizing gases on the size and the size distribution of the nanoparticles were investigated. The particles were characterized by scanning electron microscopy (SEM, X-ray diffraction (XRD and image analysis. The process parameters for the synthesis of the crystalline Ti and TiO2 nanoparticles were determined.

Efficient synthesis of silver nanoparticles from Prosopis juliflora leaf extract and its antimicrobial activity using sewage

Science.gov (United States)

Raja, K.; Saravanakumar, A.; Vijayakumar, R.

2012-11-01

In this paper, aqueous extract of fresh leaves of Prosopis juliflora was used for the synthesis of silver (Ag) nanoparticles. UV-Vis spectroscopy studies were carried out to asses silver nanoparticles formation within 5 min, scanning electron microscopic was used to characterize shape of the Ag nanoparticles, X-ray diffraction analysis confirms the nanoparticles as crystalline silver and facecentered cubic type and Fourier transform infra-red assed that shows biomolecule compounds which are responsible for reduction and capping material of silver nanoparticles. The anti microbial activity of silver nanoparticle was performed using sewage. The approach of plant-mediated synthesis appears to be cost efficient, eco-friendly and easy methods.

Luminescence enhancement of ZnO-poly(methylmethacrylate) nanocomposite films by incorporation of crystalline BaTiO{sub 3} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Kanamori, Tsuyoshi; Han, Yu; Nagao, Daisuke, E-mail: dnagao@tohoku.ac.jp; Kamezawa, Nao; Ishii, Haruyuki; Konno, Mikio

2016-09-15

Highlights: • Dielectric barium titanate (BT) nanoparticles incorporated into luminescence films. • Luminescence intensities increased by the BT nanoparticle incorporation. • Incorporation of highly dielectric nanoparticles effective for luminescence enhancement. - Abstract: Incorporation of highly dielectric nanoparticles into luminescent ZnO-polymethylmethacrylate (PMMA) nanocomposite films was undertaken to examine the effect of nanoparticle incorporation on luminescence intensity of the nanocomposite films. ZnO nanoparticles were prepared as inorganic phosphors by a precipitation method. The ZnO nanoparticles were then surface-modified with 3-methacryloxypropyltrimethoxysilane (MPTMS) to be used for fabrication of the ZnO-PMMA nanocomposite film. Barium titanate (BT) nanoparticles were synthesized with a sol-gel method as the highly dielectric nanoparticles, which were also surface-modified with the MPTMS for the incorporation into the nanocomposite films. Luminescence intensity of the nanocomposite films was successfully increased by the nanoparticle incorporation up to a BT content around 15 vol%. The luminescence intensity higher than that measured for the nanocomposite films incorporating SiO{sub 2} nanoparticles indicated that the incorporation of highly dielectric nanoparticles was an effective approach to enhance the luminescence of ZnO nanoparticles in the polymer thin films.

An analysis of facial nerve function in irradiated and unirradiated facial nerve grafts

International Nuclear Information System (INIS)

Brown, Paul D.; Eshleman, Jeffrey S.; Foote, Robert L.; Strome, Scott E.

2000-01-01

Purpose: The effect of high-dose radiation therapy on facial nerve grafts is controversial. Some authors believe radiotherapy is so detrimental to the outcome of facial nerve graft function that dynamic or static slings should be performed instead of facial nerve grafts in all patients who are to receive postoperative radiation therapy. Unfortunately, the facial function achieved with dynamic and static slings is almost always inferior to that after facial nerve grafts. In this retrospective study, we compared facial nerve function in irradiated and unirradiated nerve grafts. Methods and Materials: The medical records of 818 patients with neoplasms involving the parotid gland who received treatment between 1974 and 1997 were reviewed, of whom 66 underwent facial nerve grafting. Fourteen patients who died or had a recurrence less than a year after their facial nerve graft were excluded. The median follow-up for the remaining 52 patients was 10.6 years. Cable nerve grafts were performed in 50 patients and direct anastomoses of the facial nerve in two. Facial nerve function was scored by means of the House-Brackmann (H-B) facial grading system. Twenty-eight of the 52 patients received postoperative radiotherapy. The median time from nerve grafting to start of radiotherapy was 5.1 weeks. The median and mean doses of radiation were 6000 and 6033 cGy, respectively, for the irradiated grafts. One patient received preoperative radiotherapy to a total dose of 5000 cGy in 25 fractions and underwent surgery 1 month after the completion of radiotherapy. This patient was placed, by convention, in the irradiated facial nerve graft cohort. Results: Potential prognostic factors for facial nerve function such as age, gender, extent of surgery at the time of nerve grafting, preoperative facial nerve palsy, duration of preoperative palsy if present, or number of previous operations in the parotid bed were relatively well balanced between irradiated and unirradiated patients. However

Heating efficiency in magnetic nanoparticle hyperthermia

International Nuclear Information System (INIS)

Deatsch, Alison E.; Evans, Benjamin A.

2014-01-01

Magnetic nanoparticles for hyperthermic treatment of cancers have gained significant attention in recent years. In magnetic hyperthermia, three independent mechanisms result in thermal energy upon stimulation: Néel relaxation, Brownian relaxation, and hysteresis loss. The relative contribution of each is strongly dependent on size, shape, crystalline anisotropy, and degree of aggregation or agglomeration of the nanoparticles. We review the effects of each of these physical mechanisms in light of recent experimental studies and suggest routes for progress in the field. Particular attention is given to the influence of the collective behaviors of nanoparticles in suspension. A number of recent studies have probed the effect of nanoparticle concentration on heating efficiency and have reported superficially contradictory results. We contextualize these studies and show that they consistently indicate a decrease in magnetic relaxation time with increasing nanoparticle concentration, in both Brownian- and Néel-dominated regimes. This leads to a predictable effect on heating efficiency and alleviates a significant source of confusion within the field. - Highlights: • Magnetic nanoparticle hyperthermia. • Heating depends on individual properties and collective properties. • We review recent studies with respect to loss mechanisms. • Collective behavior is a key source of confusion in the field. • We contextualize recent studies to elucidate consistencies and alleviate confusion

Enhancement of polar crystalline phase formation in transparent PVDF-CaF{sub 2} composite films

Energy Technology Data Exchange (ETDEWEB)

Lee, Sang Goo; Ha, Jong-Wook, E-mail: jongwook@krict.re.kr; Sohn, Eun-Ho; Park, In Jun; Lee, Soo-Bok

2016-12-30

Highlights: • The crystalline phase in transparent PVDF-CaF{sub 2} composite films was investigated. • CaF{sub 2} promoted the formation of polar crystalline phases in PVDF matrix. • Ordered γ-phase was obtained by thermal treatment of as-cast films at the vicinity of its melting temperature. - Abstract: We consider the influence of calcium fluoride (CaF{sub 2}) nanoparticles on the crystalline phase formation of poly(vinylidene fluoride) (PVDF) for the first time. The transparent PVDF-CaF{sub 2} composite films were prepared by casting on PET substrates using N,N-dimethylacetamide (DMAc) as a solvent. It was found that CaF{sub 2} promoted the formation of polar crystalline phase of PVDF in composites, whereas nonpolar α-phase was dominant in the neat PVDF film prepared at the same condition. The portion of polar crystalline phase increased in proportional to the weight fraction of CaF{sub 2} in the composite films up to 10 wt%. Further addition of CaF{sub 2} suppressed completely the α-phase formation. Polar crystalline phase observed in as-cast composite films was a mixture of β- and γ-polymorph structures. It was also shown that much ordered γ-phase could be obtained through thermal treatment of as-cast PVDF-CaF{sub 2} composite film at the temperatures above the melting temperature of the composite films, but below that of γ-phase.

Ultra-small platinum and gold nanoparticles by arc plasma deposition

International Nuclear Information System (INIS)

Kim, Sang Hoon; Jeong, Young Eun; Ha, Heonphil; Byun, Ji Young; Kim, Young Dok

2014-01-01

Highlights: • Ultra-small (<2 nm) and bigger platinum and gold nanoparticles were produced by arc plasma deposition (APD). • Size and coverage of deposited nanoparticles were easily controlled with APD parameters. • Crystalline structures of deposited nanoparticles emerged only when the particle size was bigger than ∼2 nm. - Abstract: Ultra-small (<2 nm) nanoparticles of platinum and gold were produced by arc plasma deposition (APD) in a systematic way and the deposition behavior was studied. Nanoparticles were deposited on two dimensional amorphous carbon and amorphous titania thin films and characterized by transmission electron microscopy (TEM). Deposition behavior of nanoparticles by APD was studied with discharge voltage (V), discharge condenser capacitance (C), and the number of plasma pulse shots (n) as controllable parameters. The average size of intrinsic nanoparticles generated by APD process was as small as 0.9 nm and deposited nanoparticles began to have crystal structures from the particle size of about 2 nm. V was the most sensitive parameter to control the size and coverage of generated nanoparticles compared to C and n. Size of APD deposited nanoparticles was also influenced by the nature of evaporating materials and substrates

Lipid nanoparticles for the delivery of poorly water-soluble drugs.

Science.gov (United States)

Bunjes, Heike

2010-11-01

This review discusses important aspects of lipid nanoparticles such as colloidal lipid emulsions and, in particular, solid lipid nanoparticles as carrier systems for poorly water-soluble drugs, with a main focus on the parenteral and peroral use of these carriers. A short historical background of the development of colloidal lipid emulsions and solid lipid nanoparticles is provided and their similarities and differences are highlighted. With regard to drug incorporation, parameters such as the chemical nature of the particle matrix and the physicochemical nature of the drug, effects of drug partition and the role of the particle interface are discussed. Since, because of the crystalline nature of their lipid core, solid lipid nanoparticles display some additional important features compared to emulsions, their specificities are introduced in more detail. This mainly includes their solid state behaviour (crystallinity, polymorphism and thermal behaviour) and the consequences of their usually non-spherical particle shape. Since lipid nanoemulsions and -suspensions are also considered as potential means to alter the pharmacokinetics of incorporated drug substances, some underlying basic considerations, in particular concerning the drug-release behaviour of such lipid nanodispersions on dilution, are addressed as well. Colloidal lipid emulsions and solid lipid nanoparticles are interesting options for the delivery of poorly water-soluble drug substances. Their specific physicochemical properties need, however, to be carefully considered to provide a rational basis for their development into effective carrier systems for a given delivery task. © 2010 The Author. Journal compilation © 2010 Royal Pharmaceutical Society of Great Britain.

Microbes make average 2 nanometer diameter crystalline UO2 particles.

Science.gov (United States)

Suzuki, Y.; Kelly, S. D.; Kemner, K. M.; Banfield, J. F.

2001-12-01

It is well known that phylogenetically diverse groups of microorganisms are capable of catalyzing the reduction of highly soluble U(VI) to highly insoluble U(IV), which rapidly precipitates as uraninite (UO2). Because biological uraninite is highly insoluble, microbial uranyl reduction is being intensively studied as the basis for a cost-effective in-situ bioremediation strategy. Previous studies have described UO2 biomineralization products as amorphous or poorly crystalline. The objective of this study is to characterize the nanocrystalline uraninite in detail in order to determine the particle size, crystallinity, and size-related structural characteristics, and to examine the implications of these for reoxidation and transport. In this study, we obtained U-contaminated sediment and water from an inactive U mine and incubated them anaerobically with nutrients to stimulate reductive precipitation of UO2 by indigenous anaerobic bacteria, mainly Gram-positive spore-forming Desulfosporosinus and Clostridium spp. as revealed by RNA-based phylogenetic analysis. Desulfosporosinus sp. was isolated from the sediment and UO2 was precipitated by this isolate from a simple solution that contains only U and electron donors. We characterized UO2 formed in both of the experiments by high resolution-TEM (HRTEM) and X-ray absorption fine structure analysis (XAFS). The results from HRTEM showed that both the pure and the mixed cultures of microorganisms precipitated around 1.5 - 3 nm crystalline UO2 particles. Some particles as small as around 1 nm could be imaged. Rare particles around 10 nm in diameter were also present. Particles adhere to cells and form colloidal aggregates with low fractal dimension. In some cases, coarsening by oriented attachment on \\{111\\} is evident. Our preliminary results from XAFS for the incubated U-contaminated sample also indicated an average diameter of UO2 of 2 nm. In nanoparticles, the U-U distance obtained by XAFS was 0.373 nm, 0.012 nm

ZnO nanoparticles via Moringa oleifera green synthesis: Physical properties & mechanism of formation

Science.gov (United States)

Matinise, N.; Fuku, X. G.; Kaviyarasu, K.; Mayedwa, N.; Maaza, M.

2017-06-01

The research work involves the development of better and reliable method for the bio-fabrication of Zinc oxide nanoparticles through green method using Moringa Oleifera extract as an effective chelating agent. The electrochemical activity, crystalline structure, morphology, isothermal behavior, chemical composition and optical properties of ZnO nanoparticles were studied using various characterization techniques i.e. Cyclic voltammetry (CV), X-ray powder diffraction (XRD), High resolution transmission electron microscopy (HRTEM), Selected area electron diffraction (SEAD), Differential scanning calorimetry/thermogravimetric analysis (DSC/TGA), Fourier Transform Infrared analysis (FTIR) and Ultraviolet spectroscopy studies (UV-vis). The electrochemical analysis proved that the ZnO nano has high electrochemical activity without any modifications and therefore are considered as a potential candidate in electrochemical applications. The XRD pattern confirmed the crystallinity and pure phase of the sample. DSC/TGA analysis of ZnO sample (before anneal) revealed three endothermic peaks around 140.8 °C, 223.7 °C and 389.5 °C. These endothermic peaks are attributed to the loss of volatile surfactant, conversion of zinc hydroxide to zinc oxide nanoparticles and transformation of zinc oxide into zinc nanoparticles. Mechanisms of formation of the ZnO nanoparticles via the chemical reaction of the Zinc nitrate precursor with the bioactive compounds of the Moringa oleifera are proposed for each of the major family compounds: Vitamins, Flavonoids, and Phenolic acids.

Structure of Oxide Nanoparticles in Fe-16Cr MA/ODS Ferritic Steel

Energy Technology Data Exchange (ETDEWEB)

Hsiung, L; Fluss, M; Kimura, A

2010-04-06

Oxide nanoparticles in Fe-16Cr ODS ferritic steel fabricated by mechanical alloying (MA) method have been examined using high-resolution transmission electron microscopy (HRTEM) techniques. A partial crystallization of oxide nanoparticles was frequently observed in as-fabricated ODS steel. The crystal structure of crystalline oxide particles is identified to be mainly Y{sub 4}Al{sub 2}O{sub 9} (YAM) with a monoclinic structure. Large nanoparticles with a diameter larger than 20 nm tend to be incoherent and have a nearly spherical shape, whereas small nanoparticles with a diameter smaller than 10 nm tend to be coherent or semi-coherent and have faceted boundaries. The oxide nanoparticles become fully crystallized after prolonged annealing at 900 C. These results lead us to propose a three-stage formation mechanism of oxide nanoparticles in MA/ODS steels.

Dynamics of electrochemical lithiation/delithiation of graphene-encapsulated silicon nanoparticles studied by in-situ TEM.

Science.gov (United States)

Luo, Langli; Wu, Jinsong; Luo, Jiayan; Huang, Jiaxing; Dravid, Vinayak P

2014-01-24

The incorporation of nanostructured carbon has been recently reported as an effective approach to improve the cycling stability when Si is used as high-capacity anodes for the next generation Li-ion battery. However, the mechanism of such notable improvement remains unclear. Herein, we report in-situ transmission electron microscopy (TEM) studies to directly observe the dynamic electrochemical lithiation/delithiation processes of crumpled graphene-encapsulated Si nanoparticles to understand their physical and chemical transformations. Unexpectedly, in the first lithiation process, crystalline Si nanoparticles undergo an isotropic to anisotropic transition, which is not observed in pure crystalline and amorphous Si nanoparticles. Such a surprising phenomenon arises from the uniformly distributed localized voltage around the Si nanoparticles due to the highly conductive graphene sheets. It is observed that the intimate contact between graphene and Si is maintained during volume expansion/contraction. Electrochemical sintering process where small Si nanoparticles react and merge together to form large agglomerates following spikes in localized electric current is another problem for batteries. In-situ TEM shows that graphene sheets help maintain the capacity even in the course of electrochemical sintering. Such in-situ TEM observations provide valuable phenomenological insights into electrochemical phenomena, which may help optimize the configuration for further improved performance.

Cubic superparamagnetic nanoparticles of NiFe{sub 2}O{sub 4} via fast microwave heating

Energy Technology Data Exchange (ETDEWEB)

Galvão, W. S.; Freire, R. M. [Universidade Federal do Ceará–UFC, Grupo de Química de Materiais Avançados (GQMAT), Departamento de Química Analítica e Físico-Química (Brazil); Ribeiro, T. S.; Vasconcelos, I. F. [Universidade Federal do Ceará, Departamento de Engenharia Metalúrgica e de Materiais (Brazil); Costa, L. S. [State University of Campinas–UNICAMP, Department of Inorganic Chemistry, Institute of Chemistry (Brazil); Freire, V. N.; Sales, F. A. M. [Universidade Federal do Ceará, Departamento de Física, Centro de Ciências (Brazil); Denardin, J. C. [Universidad de Santiago de Chile, USACH, Departamento de Física (Chile); Fechine, P. B. A., E-mail: fechine@ufc.br [Universidade Federal do Ceará–UFC, Grupo de Química de Materiais Avançados (GQMAT), Departamento de Química Analítica e Físico-Química (Brazil)

2014-12-15

This study demonstrated the possibility of using microwave heating as a fast and cheap method for synthesizing superparamagnetic nanoparticles. In this sense, NiFe{sub 2}O{sub 4} samples were subjected to microwave heating at various temperatures to determine the lowest temperature at which the crystalline phase of the nanoparticles occurs. X-Ray powder diffraction, {sup 57}Fe Mössbauer spectroscopy, and transmission electron microscopy of the samples were performed to confirm the formed nanoparticles. It was observed a cubic structure of inverse spinel type with good crystallinity. The magnetic properties of the samples were studied using a vibrating sample magnetometer and was found to zero values to remanent magnetization and coercivity field. This behavior suggests superparamagnetic features for all samples. The crystallite size (9, 10, and 12 nm) and saturation magnetization (31–45 emu/g) were used as a function of the increase of the temperature treatment time. Blocking temperature was found by tracing remanent magnetization versus temperature.

Toxicity of laser irradiated photoactive fluoride PrF3 nanoparticles toward bacteria

International Nuclear Information System (INIS)

Pudovkin, M S; Korableva, S L; Krasheninnicova, A O; Nizamutdinov, A S; Semashko, V V; Zelenihin, P V; Alakshin, E M; Nevzorova, T A

2014-01-01

The article is devoted to exploration of biological effects of crystalline PrF 3 nanoparticles toward Salmonella typhimurium TA 98 bacteria under the laser irradiation. Obtained results show bactericidal activity of PrF 3 nanoparticles and optimal parameters of laser irradiation (power of laser irradiation, wavelength, diameter of the laser spoil, and exposure time) have been found under which the effects of bactericidal activity become the most significant. Survival of bacterial cells under laser irradiation with wavelength 532 nm in colloidal solution of PrF 3 nanoparticles was 39%, 34%, 20% for exposure times 5 minutes, 15 minutes and 30 minutes, correspondingly

Synthesis of silver nanoparticles using Matricaria recutita (Babunah plant extract and its study as mercury ions sensor

Directory of Open Access Journals (Sweden)

Imran Uddin

2017-11-01

Full Text Available Silver (Ag nanoparticles comprise a highly selective approach for development of nanosensors for the detection of Hg2+ ions. When Ag nanoparticles mixes with Hg2+ ions, loses its UV–Vis absorption intensity. Here, green synthesis of Ag nanoparticles was done using plant extract of Matricaria recutita (Babunah under ambient conditions. Biosynthesized Ag nanoparticles are well-dispersed having quasi-spherical shape and average particle size of 11nm. XRD, SAED and HRTEM analysis showed that nanoparticles are well crystalline in nature and having cubic phase of geometry. We report here highly selective colorimetric detection of mercury ions (Hg2+ using biosynthesized Ag nanoparticles. Keywords: Herbal extract, Nanosensor, Biosynthesis, Matricaria recutita, Silver nanoparticles

Estimation of lattice strain for zirconia nanoparticles based on Williamson- Hall analysis

Energy Technology Data Exchange (ETDEWEB)

Aly, Kamal A., E-mail: kamalaly2001@gmail.com [Physics Department, Faculty of Science & Arts, Khullais, University of Jeddah, Jeddah (Saudi Arabia); Physics Department, Faculty of Science, Al-Azhar University, Assiut Branch, Assiut (Egypt); Khalil, N.M. [Chemistry Department, Faculty of Science & Arts, Khullais, University of Jeddah, Jeddah (Saudi Arabia); Refractories, Ceramics and Building Materials Department, National Research Centre, 12311, Cairo (Egypt); Algamal, Yousif [Chemistry Department, Faculty of Science & Arts, Khullais, University of Jeddah, Jeddah (Saudi Arabia); Saleem, Qaid M.A. [Chemistry Department, Faculty of Science & Arts, Khullais, University of Jeddah, Jeddah (Saudi Arabia); Aden University, Shabwa (Yemen)

2017-06-01

Nanoparticles of Zirconia were prepared (ZrO{sub 2}) by the neutralization of zirconium oxychloride octahydrate (ZrOCl{sub 2}-8H{sub 2}O) (2M) and ammonia solution (2M) at pH 8. The ZrO{sub 2} crystalline state was revealed by X-ray diffraction (XRD). The analysis of Scanning electron microscopy (SEM) and Transmission Electron microscope (TEM) images reveals that the as-synthesized ZrO{sub 2} particles at firing temperature of 800 °C are uniform and of range of 30 nm. Increasing of the temperature up to 1100 °C leads to the increase in particle size and alters the powders shape due to agglomeration arose from zirconia calcination as well as the increase in particle size. The X-ray peak broadening analysis (XRDBA) was used in the estimation of the crystalline size. Williamson-Hall (W-H) analysis was applied successfully to determine the energy density, stress, and the strain values via uniform deformation model (UDM), uniform deformation stress model (UDSM) and uniform deformation energy density model (UDEDM). The mean of the strain root square was calculated. The different strain values obtained from these models predicting the zirconia isotropic behavior. In addition to that, the W-H analysis results were discussed in terms of that obtained by Scherrer’s relationship, SEM and TEM images. - Graphical abstract: XRD patterns for zirconia nano-particles at different calcined temperature. - Highlights: • Nanoparticles of Zirconia (ZrO{sub 2}) were synthesized. • The ZrO{sub 2} crystalline state was revealed by XRD, SEM and TEM. • SEM and TEM images reveals that the ZrO{sub 2} particles are uniform and relatively small. • Both blocky particles and the powders shape are affected by the firing temperature. • The crystalline sizes were estimated using X-ray peak broadening analysis (XRDBA).

Synthesis of barium titanate crystalline nanoparticles using hydrothermal microwave method; Obtencao de nanoparticulas cristalinas de titanato de bario usando metodo hidrotermal assistido por microondas

Energy Technology Data Exchange (ETDEWEB)

Souza, A.E.; Silva, R.A.; Teixeira, S.R. [Universidade Estadual Paulista (DFQB/FCT/UNESP), Presidente Prudente, SP (Brazil). Dept. de Fisica, Quimica e Biologia. Lab. de Compositos e Ceramicas Funcionais; Moreira, M.L. [Universidade Federal de Sao Carlos (LiEC/UFSCAR), SP (Brazil). Lab. Interdisciplinar de Eletroquimica e Ceramica; Volanti, D.P.; Longo, E. [Universidade Estadual Paulista (LiEC/UNESP), Araraquara, SP (Brazil). Lab. Interdisciplinar de Eletroquimica e Ceramica

2009-07-01

The hydrothermal microwave method (HTMW) was used in the synthesis of barium titanate (BaTiO{sub 3}) nanoparticles. The solution was prepared in deionized water by using titanium (IV) isopropoxide (C{sub 12}H{sub 28}O{sub 4}Ti), barium chloride (BaCl{sub 2}.2H{sub 2}O) and potassium hydroxide (KOH). Afterwards it was heated in an adapted conventional microwave oven. The system is composed of a temperature controller with thermocouple, a hermetic camera of reaction made of teflon, a manometer and a safety valve. The solution was heated to 140 deg C, at a 140 deg C/min heating rate, and maintained at this temperature for 40 minutes. The obtained ceramic powder was characterized by using X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The XRD data confirms the formation of a high crystalline ceramic material with perovskite structure. The FE-SEM images reveal morphologies with dimensions varying from 27 to 54 nm. (author)

Novel banana peel pectin mediated green route for the synthesis of hydroxyapatite nanoparticles and their spectral characterization.

Science.gov (United States)

Gopi, D; Kanimozhi, K; Bhuvaneshwari, N; Indira, J; Kavitha, L

2014-01-24

Hydroxyapatite [HAP, Ca10(PO4)6(OH)2] is the main inorganic component of natural bone and is widely used in various biomedical applications. In this paper, we have reported the synthesis of HAP nanoparticles by banana peel pectin mediated green template method. The pectin extracted from the peels of banana and its various concentrations were exploited in our study to achieve a controlled crystallinity, particle size as well as uniform morphology of HAP. The extracted pectin was characterized by spectral techniques like Fourier transform infrared spectroscopy (FTIR) for the functional group analysis, proton-1 nuclear magnetic resonance spectroscopy ((1)H NMR) and carbon-13 nuclear magnetic resonance spectroscopy ((13)C NMR) for the identification of H and C atoms in the extracted pectin, respectively. The HAP nanoparticles were synthesized using different concentrations of the as-extracted pectin. The purity, crystallinity and morphology of the as-synthesized HAP nanoparticles were evaluated by FTIR, X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDAX) and transmission electron microscopy (TEM), respectively. Moreover the antibacterial activity of HAP nanoparticles was evaluated against the gram positive and negative bacteria like Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), respectively. The experimental results revealed that the HAP nanoparticles synthesized in the presence of an optimized concentration of pectin are pure, low crystalline, spherical and discrete particles with reduced size. Also, the HAP sample derived in the presence of pectin showed an enhanced antibacterial activity than that of the HAP synthesized in the absence of pectin. Hence, the HAP nanoparticles synthesized using pectin as a green template can act as a good biomaterial for biomedical applications. Copyright © 2013 Elsevier B.V. All rights reserved.

Impact of the Formulation Pathway on the Colloidal State and Crystallinity of Poly-ε-caprolactone Particles Prepared by Solvent Displacement.

Science.gov (United States)

Pucci, Carlotta; Cousin, Fabrice; Dole, François; Chapel, Jean-Paul; Schatz, Christophe

2018-02-20

The formulation pathway and/or the mixing method are known to be relevant in many out-of-equilibrium processes. In this work, we studied the effect of the mixing conditions on the physicochemical properties of poly-ε-caprolactone (PCL) particles prepared by solvent displacement. More specifically, water was added in one shot (fast addition) or drop by drop to PCL solution in tetrahydrofuran (THF) to study the impact of the mixing process on particle properties including size, stability, and crystallinity. Two distinct composition maps representing the Ouzo domain characteristic of the presence of metastable nanoparticles have been established for each mixing method. Polymer nanoparticles are formed in the Ouzo domain according to a nucleation and growth (or aggregation) mechanism. The fast addition promotes a larger nucleation rate, thus favoring the formation of small and uniform particles. For the drop-by-drop addition, for which the polymer solubility gradually decreases, the composition trajectories systematically cross an intermediate unstable region between the solubility limit of the polymer and the Ouzo domain. This leads to heterogeneous nucleation as shown by the formation of larger and less stable particles. Particles formed in the Ouzo domain have semi-crystalline properties. The PCL melting point is decreased with the THF fraction trapped in particles in accordance with Flory's theory for melt crystallization. On the other hand, the degree of crystallinity is constant, around 20% regardless of the THF fraction. No difference between fast and slow addition could be detected on the semi-crystalline properties of the particles which emphasize that thermodynamic rather than kinetic factors drive the polymer crystallization in particles. The recovery of bulk PCL crystallinity after the removal of THF from particles tends to confirm this hypothesis.

Efficient synthesis of silver nanoparticles from Prosopis juliflora leaf extract and its antimicrobial activity using sewage.

Science.gov (United States)

Raja, K; Saravanakumar, A; Vijayakumar, R

2012-11-01

In this paper, aqueous extract of fresh leaves of Prosopis juliflora was used for the synthesis of silver (Ag) nanoparticles. UV-Vis spectroscopy studies were carried out to asses silver nanoparticles formation within 5 min, scanning electron microscopic was used to characterize shape of the Ag nanoparticles, X-ray diffraction analysis confirms the nanoparticles as crystalline silver and facecentered cubic type and Fourier transform infra-red assed that shows biomolecule compounds which are responsible for reduction and capping material of silver nanoparticles. The anti microbial activity of silver nanoparticle was performed using sewage. The approach of plant-mediated synthesis appears to be cost efficient, eco-friendly and easy methods. Copyright © 2012 Elsevier B.V. All rights reserved.

Green synthesis of gold and silver nanoparticles using Hibiscus rosa sinensis

Science.gov (United States)

Philip, Daizy

2010-03-01

Biological synthesis of gold and silver nanoparticles of various shapes using the leaf extract of Hibiscus rosa sinensis is reported. This is a simple, cost-effective, stable for long time and reproducible aqueous room temperature synthesis method to obtain a self-assembly of Au and Ag nanoparticles. The size and shape of Au nanoparticles are modulated by varying the ratio of metal salt and extract in the reaction medium. Variation of pH of the reaction medium gives silver nanoparticles of different shapes. The nanoparticles obtained are characterized by UV-vis, transmission electron microscopy (TEM), X-ray diffraction (XRD) and FTIR spectroscopy. Crystalline nature of the nanoparticles in the fcc structure are confirmed by the peaks in the XRD pattern corresponding to (1 1 1), (2 0 0), (2 2 0) and (3 1 1) planes, bright circular spots in the selected area electron diffraction (SAED) and clear lattice fringes in the high-resolution TEM image. From FTIR spectra it is found that the Au nanoparticles are bound to amine groups and the Ag nanoparticles to carboxylate ion groups.

Anisotropy of the elastic properties of crystalline cellulose Iß from first principles density functional theory with Van der Waals interactions

Science.gov (United States)

Fernando L. Dri; Louis G. Jr. Hector; Robert J. Moon; Pablo D. Zavattieri

2013-01-01

In spite of the significant potential of cellulose nanocrystals as functional nanoparticles for numerous applications, a fundamental understanding of the mechanical properties of defect-free, crystalline cellulose is still lacking. In this paper, the elasticity matrix for cellulose Iß with hydrogen bonding network A was calculated using ab initio...

Starch nanoparticles resulting from combination of dry heating under mildly acidic conditions and homogenization.

Science.gov (United States)

Kim, Jong Hun; Kim, Jiyeon; Park, Eun Young; Kim, Jong-Yea

2017-07-15

To modify starch granular structure, normal maize starch was subjected to dry heating with various amounts of 1.0M HCl (1.2, 1.4 or 1.6mL) and different treatment times (2, 4 or 8h). For all reaction conditions, at least 80% of the starch substance was recovered, and amylose and amylopectin B1 chains were preferentially cleaved. As acidic condition and/or treatment time increased, the treated granules were readily fragmented by homogenization. The treatment appeared to alter short-range crystalline structure (FT-IR), but long-range crystalline structure (XRD) remained intact. Homogenization for 60min fragmented the treated starch granules (subjected to reaction condition of 1.4mL/4h, 1.6mL/2h, and 1.6mL/4h) into nanoparticles consisting of individual platelet-like and spherical particles with diameters less than 100nm. However, the fragmentation caused obvious damage in the long-range crystalline structure of starch nanoparticles, while the short-range chain associations remained relatively intact. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of sulfurization temperature on the property of Cu2ZnSnS4 thin film by eco-friendly nanoparticle ink method

Science.gov (United States)

Wang, Wei; Shen, Honglie; Yao, Hanyu; Shang, Huirong; Tang, ZhengXia; Li, Yufang

2017-09-01

Cu2ZnSnS4 (CZTS) thin films were fabricated by a low-cost nanoparticle ink method. The eco-friendly hydrophilic CZTS nanoparticles were mixed with low-cost n-propanol to form nanoparticle ink. To improve crystallinity and remove oxygen element, the CZTS thin films were sulfurized further. The effects of sulfurization temperature on the structure, morphologies, and photovoltaic performances of CZTS thin films were investigated. The results showed that the crystallinity of CZTS thin film was improved with increasing sulfurization temperature. The surface morphology studies demonstrated the formation of compact and homogenous CZTS thin film at a sulfurization temperature of 600 °C. By optimizing thickness of CZTS thin film, the CZTS thin-film solar cell with an optimal efficiency of 2.1% was obtained.

Synthesis, characterization and antimicrobial activity of dextran stabilized silver nanoparticles in aqueous medium.

Science.gov (United States)

Bankura, K P; Maity, D; Mollick, M M R; Mondal, D; Bhowmick, B; Bain, M K; Chakraborty, A; Sarkar, J; Acharya, K; Chattopadhyay, D

2012-08-01

A simple one-step rapid synthetic route is described for the preparation of silver nanoparticles by reduction of silver nitrate (AgNO3) using aqueous dextran solution which acts as both reducing and capping agent. The formation of silver nanoparticles is assured by characterization with UV-vis spectroscopy, atomic force microscopy (AFM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The absorbance of the silver nanoparticles is observed at 423 nm. The AFM image clearly shows the surface morphology of the well-dispersed silver nanoparticles with size range of 10-60 nm. TEM images show that the nanoparticles are spherical in shape with ∼5-10 nm dimensions. The crystallinity of Ag nanoparticles is assured by XRD analysis. The antimicrobial activity of as synthesized silver nanoparticles is tested against the bacteria, Bacillus subtilis, Bacillus cereus, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. The bacterial growth is inhibited by gradual reduction of the concentration of the silver nanoparticles. Copyright © 2012 Elsevier Ltd. All rights reserved.

ZnO nanoparticles via Moringa oleifera green synthesis: Physical properties & mechanism of formation

International Nuclear Information System (INIS)

Matinise, N.; Fuku, X.G.; Kaviyarasu, K.; Mayedwa, N.; Maaza, M.

2017-01-01

Highlights: • Biosynthesis of ZnO nanoparticlesl by green process using Moringa Oliefera extract. • Electrochemical studies were confirmed by cyclic and Square wave voltammetry. • XRD, HRTEM, TGA/DSC, FTIR were used to characterized the nanoparticles. - Abstract: The research work involves the development of better and reliable method for the bio-fabrication of Zinc oxide nanoparticles through green method using Moringa Oleifera extract as an effective chelating agent. The electrochemical activity, crystalline structure, morphology, isothermal behavior, chemical composition and optical properties of ZnO nanoparticles were studied using various characterization techniques i.e. Cyclic voltammetry (CV), X-ray powder diffraction (XRD), High resolution transmission electron microscopy (HRTEM), Selected area electron diffraction (SEAD), Differential scanning calorimetry/thermogravimetric analysis (DSC/TGA), Fourier Transform Infrared analysis (FTIR) and Ultraviolet spectroscopy studies (UV–vis). The electrochemical analysis proved that the ZnO nano has high electrochemical activity without any modifications and therefore are considered as a potential candidate in electrochemical applications. The XRD pattern confirmed the crystallinity and pure phase of the sample. DSC/TGA analysis of ZnO sample (before anneal) revealed three endothermic peaks around 140.8 °C, 223.7 °C and 389.5 °C. These endothermic peaks are attributed to the loss of volatile surfactant, conversion of zinc hydroxide to zinc oxide nanoparticles and transformation of zinc oxide into zinc nanoparticles. Mechanisms of formation of the ZnO nanoparticles via the chemical reaction of the Zinc nitrate precursor with the bioactive compounds of the Moringa oleifera are proposed for each of the major family compounds: Vitamins, Flavonoids, and Phenolic acids.

ZnO nanoparticles via Moringa oleifera green synthesis: Physical properties & mechanism of formation

Energy Technology Data Exchange (ETDEWEB)

Matinise, N., E-mail: nmatinise@tlabs.ac.za [UNESCO-UNISA Africa Chair in Nanoscience-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Western Cape (South Africa); Fuku, X.G., E-mail: fuku@tlabs.ac.za [UNESCO-UNISA Africa Chair in Nanoscience-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Western Cape (South Africa); Kaviyarasu, K., E-mail: kasinathankariyarasu@gmail.com [UNESCO-UNISA Africa Chair in Nanoscience-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Western Cape (South Africa); Mayedwa, N., E-mail: nmyedi@gmail.com [UNESCO-UNISA Africa Chair in Nanoscience-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Western Cape (South Africa); Maaza, M., E-mail: maaza@tlabs.ac.za [UNESCO-UNISA Africa Chair in Nanoscience-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Western Cape (South Africa)

2017-06-01

Highlights: • Biosynthesis of ZnO nanoparticlesl by green process using Moringa Oliefera extract. • Electrochemical studies were confirmed by cyclic and Square wave voltammetry. • XRD, HRTEM, TGA/DSC, FTIR were used to characterized the nanoparticles. - Abstract: The research work involves the development of better and reliable method for the bio-fabrication of Zinc oxide nanoparticles through green method using Moringa Oleifera extract as an effective chelating agent. The electrochemical activity, crystalline structure, morphology, isothermal behavior, chemical composition and optical properties of ZnO nanoparticles were studied using various characterization techniques i.e. Cyclic voltammetry (CV), X-ray powder diffraction (XRD), High resolution transmission electron microscopy (HRTEM), Selected area electron diffraction (SEAD), Differential scanning calorimetry/thermogravimetric analysis (DSC/TGA), Fourier Transform Infrared analysis (FTIR) and Ultraviolet spectroscopy studies (UV–vis). The electrochemical analysis proved that the ZnO nano has high electrochemical activity without any modifications and therefore are considered as a potential candidate in electrochemical applications. The XRD pattern confirmed the crystallinity and pure phase of the sample. DSC/TGA analysis of ZnO sample (before anneal) revealed three endothermic peaks around 140.8 °C, 223.7 °C and 389.5 °C. These endothermic peaks are attributed to the loss of volatile surfactant, conversion of zinc hydroxide to zinc oxide nanoparticles and transformation of zinc oxide into zinc nanoparticles. Mechanisms of formation of the ZnO nanoparticles via the chemical reaction of the Zinc nitrate precursor with the bioactive compounds of the Moringa oleifera are proposed for each of the major family compounds: Vitamins, Flavonoids, and Phenolic acids.

Phytosynthesis and Characterization of Silver Nanoparticles Using Callus of JATROPHA CURCAS: a Biotechnological Approach

Science.gov (United States)

Demissie, A. G.; Lele, S. S.

2013-06-01

The present study reports a rapid plant-based biosynthesis of silver nanoparticles using callus extract of Jatropha curcas L. The particle size and morphological analyses were carried out using Zetasizer, SEM, TEM. The physicochemical properties were monitored using UV-Vis spectroscopic, IR and DSC. The formation of silver nanoparticle was confirmed by using UV-Vis spectrophotometer and absorbance peaks at 421 nm. The silver nanoparticle was found to be a negatively charged with size ranging from 2 nm to 50 nm. The morphology of the nanoparticle is uniformly spherical and has a dispersion ratio of 0.14. The physicochemical study using DSC indicated significant thermal stability and crystalline nature of the nanoparticle. This intracellular biosynthesis of silver nanoparticles is simple, cheap and eco-friendly than other mechanical and chemical approaches.

Poorly crystalline hydroxyapatite: A novel adsorbent for enhanced fulvic acid removal from aqueous solution

Science.gov (United States)

Wei, Wei; Yang, Lei; Zhong, Wenhui; Cui, Jing; Wei, Zhenggui

2015-03-01

In this study, poorly crystalline hydroxyapatite (HAP) was developed as an efficient adsorbent for the removal of fulvic acid (FA) from aqueous solution. Surface functionality, crystallinity, and morphology of the synthetic adsorbent were studied by Fourier-transformation infrared (FT-IR) spectroscopy, powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). The effects of various parameters such as crystallinity of adsorbent, contact time, adsorbent dosage, pH, initial adsorbate concentration, temperature, ionic strength and the presence of alkaline earth metal ions on FA adsorption were investigated. Results indicated that the nanosized HAP calcined at lower temperature was poorly crystalline (Xc = 0.23) and had better adsorption capacity for FA than those (Xc = 0.52, 0.86) calcined at higher temperature. FA removal was increased with increases of adsorbent dosage, temperature, ionic strength and the presence of alkali earth metal ions, but decreased as the pH increased. Kinetic studies showed that pseudo-second-order kinetic model better described the adsorption process. Equilibrium data were best described by Sips models, and the estimated maximum adsorption capacity of poorly crystalline HAP was 90.20 mg/g at 318 K, displaying higher efficiency for FA removal than previously reported adsorbents. FT-IR results revealed that FA adsorption over the adsorbent could be attributed to the surface complexation between the oxygen atom of functional groups of FA and calcium ions of HAP. Regeneration studies indicated that HAP could be recyclable for a long term. Findings of the present work highlight the potential for using poorly crystalline HAP nanoparticles as an effective and recyclable adsorbent for FA removal from aqueous solution.

Food protein-based phytosterol nanoparticles: fabrication and characterization.

Science.gov (United States)

Cao, Wen-Jun; Ou, Shi-Yi; Lin, Wei-Feng; Tang, Chuan-He

2016-09-14

The development of food-grade (nano)particles as a delivery system for poorly water soluble bioactives has recently attracted increasing attention. This work is an attempt to fabricate food protein-based nanoparticles as delivery systems for improving the water dispersion and bioaccessibility of phytosterols (PS) by an emulsification-evaporation method. The fabricated PS nanoparticles were characterized in terms of particle size, encapsulation efficiency (EE%) and loading amount (LA), and ξ-potential. Among all the test proteins, including soy protein isolate (SPI), whey protein concentrate (WPC) and sodium caseinate (SC), SC was confirmed to be the most suitable protein for the PS nano-formulation. Besides the type of protein, the particle size, EE% and LA of PS in the nanoparticles varied with the applied protein concentration in the aqueous phase and organic volume fraction. The freeze-dried PS nanoparticles with SC exhibited good water re-dispersion behavior and low crystallinity of PS. The LA of PS in the nanoparticles decreased upon storage, especially at high temperatures (e.g., >25 °C). The PS in the fabricated nanoparticles exhibited much better bioaccessibility than free PS. The findings would be of relevance for the fabrication of food-grade colloidal phytosterols, with great potential to be applied in functional food formulations.

Water flattens graphene wrinkles: laser shock wrapping of graphene onto substrate-supported crystalline plasmonic nanoparticle arrays.

Science.gov (United States)

Hu, Yaowu; Lee, Seunghyun; Kumar, Prashant; Nian, Qiong; Wang, Wenqi; Irudayaraj, Joseph; Cheng, Gary J

2015-12-21

Hot electron injection into an exceptionally high mobility material can be realized in graphene-plasmonic nanoantenna hybrid nanosystems, which can be exploited for several front-edge applications including photovoltaics, plasmonic waveguiding and molecular sensing at trace levels. Wrinkling instabilities of graphene on these plasmonic nanostructures, however, would cause reactive oxygen or sulfur species to diffuse and react with the materials, decrease charge transfer rates and block intense hot-spots. No ex situ graphene wrapping technique has been explored so far to control these wrinkles. Here, we present a method to generate seamless integration by using water as a flyer to transfer the laser shock pressure to wrap graphene onto plasmonic nanocrystals. This technique decreases the interfacial gap between graphene and the covered substrate-supported plasmonic nanoparticle arrays by exploiting a shock pressure generated by the laser ablation of graphite and the water impermeable nature of graphene. Graphene wrapping of chemically synthesized crystalline gold nanospheres, nanorods and bipyramids with different field confinement capabilities is investigated. A combined experimental and computational method, including SEM and AFM morphological investigation, molecular dynamics simulation, and Raman spectroscopy characterization, is used to demonstrate the effectiveness of this technique. Graphene covered gold bipyramid exhibits the best result among the hybrid nanosystems studied. We have shown that the hybrid system fabricated by laser shock can be used for enhanced molecular sensing. The technique developed has the characteristics of tight integration, and chemical/thermal stability, is instantaneous in nature, possesses a large scale and room temperature processing capability, and can be further extended to integrate other 2D materials with various 0-3D nanomaterials.

Thermal, optical and vibrational studies of tyrosine doped LaF3:Ce nanoparticles for bioimaging and biotagging

Science.gov (United States)

Singh, Amit T.

2018-05-01

Upconversion quantum dots of tyrosine doped LaF3:Ce nanoparticles have been synthesized by wet chemical route. The thermal studies (TGA/DTA) confirm the crystallinity and stability of different phases of synthesized nanoparticles. The UV-Visible spectra show multiple absorption edges at 215.60 nm and 243.10 nm indicating quantum dot nature of the synthesized nanoparticles. The PL spectra showed upconversion with sharp emission peak at 615 nm (red colour). The FT-RAMAN spectra of the synthesized nanoparticles show the modification of the surface of the nanoparticles in the form of functional groups and skeletal groups. Upconversion nature of the synthesized nanoparticles indicates their potential application in bioimaging and biotagging.

Hybrid composite thin films composed of tin oxide nanoparticles and cellulose

International Nuclear Information System (INIS)

Mahadeva, Suresha K; Nayak, Jyoti; Kim, Jaehwan

2013-01-01

This paper reports the preparation and characterization of hybrid thin films consisting of tin oxide (SnO 2 ) nanoparticles and cellulose. SnO 2 nanoparticle loaded cellulose hybrid thin films were fabricated by a solution blending technique, using sodium dodecyl sulfate as a dispersion agent. Scanning and transmission electron microscopy studies revealed uniform dispersion of the SnO 2 nanoparticles in the cellulose matrix. Reduction in the crystalline melting transition temperature and tensile properties of cellulose was observed due to the SnO 2 nanoparticle loading. Potential application of these hybrid thin films as low cost, flexible and biodegradable humidity sensors is examined in terms of the change in electrical resistivity of the material exposed to a wide range of humidity as well as its response–recovery behavior. (paper)

Biogenic synthesis of silver nanoparticles by leaf extract of Cassia angustifolia

Science.gov (United States)

Amaladhas, T. Peter; Sivagami, S.; Akkini Devi, T.; Ananthi, N.; Priya Velammal, S.

2012-12-01

In this study Cassia angustifolia (senna) is used for the environmentally friendly synthesis of silver nanoparticles. Stable silver nanoparticles having symmetric surface plasmon resonance (SPR) band centred at 420 nm were obtained within 10 min at room temperature by treating aqueous solutions of silver nitrate with C. angustifolia leaf extract. The water soluble components from the leaves, probably the sennosides, served as both reducing and capping agents in the synthesis of silver nanoparticles. The nanoparticles were characterized using UV-Vis, Fourier transform infrared (FTIR) spectroscopic techniques and transmission electron microscopy (TEM). The nanoparticles were poly-dispersed, spherical in shape with particle size in the range 9-31 nm, the average size was found to be 21.6 nm at pH 11. The zeta potential was -36.4 mV and the particles were stable for 6 months. The crystalline phase of the nanoparticles was confirmed from the selected area diffraction pattern (SAED). The rate of formation and size of silver nanoparticles were pH dependent. Functional groups responsible for capping of silver nanoparticles were identified from the FTIR spectrum. The synthesized silver nanoparticles exhibited good antibacterial potential against Escherichia coli and Staphylococcus aureus.

Biogenic synthesis of silver nanoparticles by leaf extract of Cassia angustifolia

International Nuclear Information System (INIS)

Peter Amaladhas, T; Akkini Devi, T; Ananthi, N; Priya Velammal, S; Sivagami, S

2012-01-01

In this study Cassia angustifolia (senna) is used for the environmentally friendly synthesis of silver nanoparticles. Stable silver nanoparticles having symmetric surface plasmon resonance (SPR) band centred at 420 nm were obtained within 10 min at room temperature by treating aqueous solutions of silver nitrate with C. angustifolia leaf extract. The water soluble components from the leaves, probably the sennosides, served as both reducing and capping agents in the synthesis of silver nanoparticles. The nanoparticles were characterized using UV–Vis, Fourier transform infrared (FTIR) spectroscopic techniques and transmission electron microscopy (TEM). The nanoparticles were poly-dispersed, spherical in shape with particle size in the range 9–31 nm, the average size was found to be 21.6 nm at pH 11. The zeta potential was –36.4 mV and the particles were stable for 6 months. The crystalline phase of the nanoparticles was confirmed from the selected area diffraction pattern (SAED). The rate of formation and size of silver nanoparticles were pH dependent. Functional groups responsible for capping of silver nanoparticles were identified from the FTIR spectrum. The synthesized silver nanoparticles exhibited good antibacterial potential against Escherichia coli and Staphylococcus aureus. (paper)

Structural Properties of Nanoparticles TiO2/PVA Polymeric Films

Directory of Open Access Journals (Sweden)

Samara A. Madhloom

2018-04-01

Full Text Available In this research, X-ray diffraction of the powder (PVA polymer, titanium dioxide with two parti-cle sizes and (TiO2 (15.7 nm/PVA and TiO2 (45.7 nm/PVA films have been studied,the amount of polymer is (0.5 g and (0.01g from each particle sizes of nanoparticles will be used. Casting method is used to prepare homogeneous films on glass petri dishes. All parameters ac-counted for the X-ray diffraction; full width half maximum (FWHM, Miller indices (hkl, size of crystalline (D, Specific Surface Area (S and Dislocation Density (δ. The nature of the structural of materials and films will be investigated. The XRD pattern of PVA polymer has semi-crystalline nature and the titanium dioxide with two particle sizes have crystalline structure; ana-tase type. While the mixture between these materials led to appearing some crystalline peaks into XRD pattern of PVA polymer

Mg(OH){sub 2} nanoparticles produced at room temperature by an innovative, facile, and scalable synthesis route

Energy Technology Data Exchange (ETDEWEB)

Taglieri, Giuliana, E-mail: giuliana.taglieri@univaq.it; Felice, Benito; Daniele, Valeria; Ferrante, Fabiola [University of L’Aquila, Department of Industrial and Information Engineering and Economics (Italy)

2015-10-15

Nanoparticles form the fundamental building blocks for many exciting applications in various scientific disciplines. However, the problem of the large-scale synthesis of nanoparticles remains challenging. An original, eco-friendly, single step, and scalable method to produce magnesium hydroxide nanoparticles in aqueous suspensions is here presented. The method, based on an exchange ion process, is extremely simple and rapid (few minutes). It employs cheap or renewable reactants, operates at room temperature and does not require intermediate steps (washings/purifications) to eliminate undesired compounds. Moreover, it is possible to regenerate the exchange material and to reuse it for new operation of synthesis, according to a cyclic procedure, providing potential aptitudes of scalability of nanoparticles production. Some of the synthesis parameters are varied, and structural and morphological features of the produced nanoparticles, after few seconds from the beginning of the synthesis up to the ending time, are investigated by means of several techniques, such as X-ray diffraction (profile fitting and Rietveld refinement), transmission electron microscopy, infrared spectroscopy, thermal analyses, and surface area measurements. In any case, pure and stable suspensions are produced, characterized by crystalline and mesoporous Mg(OH){sub 2} nanoparticles, with lamellar morphology. In particular, the nanolamellas appeared constituted by a superimposition of hexagonally plated and crystalline nanosized precursors (2–3 nm in dimensions), crystallographically oriented.

The crystallization and physical properties of Al-doped ZnO nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Chen, K.J. [Institute of Microelectronics and Department of Electrical Engineering, Center for Micro/Nano Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Fang, T.H. [Institute of Mechanical and Electromechanical Engineering, National Formosa University, Yunlin 632, Taiwan (China); Hung, F.Y. [Institute of Nanotechnology and Microsystems Engineering, Center for Micro/Nano Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan (China)], E-mail: fyhung@mail.mse.ncku.edu.tw; Ji, L.W. [Institute of Mechanical and Electromechanical Engineering, National Formosa University, Yunlin 632, Taiwan (China); Chang, S.J.; Young, S.J. [Institute of Microelectronics and Department of Electrical Engineering, Center for Micro/Nano Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Hsiao, Y.J. [Department of Materials Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan (China)

2008-07-15

Un-doped Al (0-9 at.%) nanoparticles and doped ZnO powders were prepared by the sol-gel method. The nanoparticles were heated at 700-800 deg. C for 1 h in air and then analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectra and photoluminescence (PL). The results of un-doped (ZnO) and Al-doped ZnO (AZO) nanoparticles were also compared to investigate the structural characteristics and physical properties. XRD patterns of AZO powders were similar to those of ZnO powders, indicating that micro-Al ions were substituted for Zn atoms and there were no variations in the structure of the ZnO nanoparticles. From the XRD and SEM data, the grain size of the AZO nanoparticles increased from 34.41 to 40.14 nm when the annealing temperature was increased. The Raman intensity of the AZO nanoparticles (Al = 5 at.%) increased when the annealing temperature was increased. Increasing the degree of crystalline not only reduced the residual stress, but also improved the physical properties of the nanoparticles.

The crystallization and physical properties of Al-doped ZnO nanoparticles

International Nuclear Information System (INIS)

Chen, K.J.; Fang, T.H.; Hung, F.Y.; Ji, L.W.; Chang, S.J.; Young, S.J.; Hsiao, Y.J.

2008-01-01

Un-doped Al (0-9 at.%) nanoparticles and doped ZnO powders were prepared by the sol-gel method. The nanoparticles were heated at 700-800 deg. C for 1 h in air and then analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectra and photoluminescence (PL). The results of un-doped (ZnO) and Al-doped ZnO (AZO) nanoparticles were also compared to investigate the structural characteristics and physical properties. XRD patterns of AZO powders were similar to those of ZnO powders, indicating that micro-Al ions were substituted for Zn atoms and there were no variations in the structure of the ZnO nanoparticles. From the XRD and SEM data, the grain size of the AZO nanoparticles increased from 34.41 to 40.14 nm when the annealing temperature was increased. The Raman intensity of the AZO nanoparticles (Al = 5 at.%) increased when the annealing temperature was increased. Increasing the degree of crystalline not only reduced the residual stress, but also improved the physical properties of the nanoparticles

Green Synthesis of Silver Nanoparticles by using Eucalyptus Globulus Leaf Extract

Science.gov (United States)

Balamurugan, Madheswaran; Saravanan, Shanmugam

2017-12-01

A single step eco-friendly, energy efficient and economically scalable green method was employed to synthesize silver nanoparticles. In this work, the synthesis of silver nanoparticles using Eucalyptus globulus leaf extract as reducing and capping agent along with water as solvent at normal room temperature is described. Silver nanoparticles were prepared from aqueous silver nitrate solution by adding the leaf extract. The prepared nanoparticles were characterized by using UV-visible Spectrophotometer, X-ray diffractometer, High Resolution Transmission Electron Microscope (HR-TEM) and Fourier Transform Infrared Spectroscope (FTIS). X-ray diffraction studies brought to light the crystalline nature and the face centered cubic structure of the silver nanoparticles. Using HR-TEM. the nano sizes and morphology of the particles were studied. The mean sizes of the prepared silver nanoparticles ranged from 30 to 36 nm. The density of the particles was tuned by varying the molar ratio of silver nitrate. FTIS studies showed the functional group of organic molecules which were located on the surface of the silver nanoparticles. Originating from the leaf extracts, these organic molecules reduced and capped the particles.

Bark extract mediated green synthesis of silver nanoparticles: Evaluation of antimicrobial activity and antiproliferative response against osteosarcoma

Energy Technology Data Exchange (ETDEWEB)

Nayak, Debasis; Ashe, Sarbani; Rauta, Pradipta Ranjan; Kumari, Manisha; Nayak, Bismita, E-mail: nayakb@nitrkl.ac.in

2016-01-01

In the current investigation we report the biosynthesis potentials of bark extracts of Ficus benghalensis and Azadirachta indica for production of silver nanoparticle without use of any external reducing or capping agent. The appearance of dark brown color indicated the complete nanoparticle synthesis which was further validated by absorbance peak by UV–vis spectroscopy. The morphology of the synthesized particles was characterized by Field emission- scanning electron microscopy (Fe-SEM) and atomic force microscopy (AFM). The X-ray diffraction (XRD) patterns clearly illustrated the crystalline phase of the synthesized nanoparticles. ATR-Fourier Transform Infrared (ATR-FTIR) spectroscopy was performed to identify the role of various functional groups in the nanoparticle synthesis. The synthesized nanoparticles showed promising antimicrobial activity against Gram negative (Escherichia coli, Pseudomonas aeruginosa and Vibrio cholerae) and Gram positive (Bacillus subtilis) bacteria. The synthesized nano Ag also showed antiproliferative activity against MG-63 osteosarcoma cell line in a dose dependent manner. Thus, these synthesized Ag nanoparticles can be used as a broad spectrum therapeutic agent against osteosarcoma and microorganisms. - Highlights: • Rapid, cost effective, benign synthesis of AgNPs using novel bark extracts • Color change and absorbance peak observed at 426 and 420 nm due to SPR phenomenon • Crystalline and spherical nanoparticles having average size of ~ 40 and ~ 50 nm each • Highly enhanced antimicrobial activity against human nosocomial strains • Demonstrated dose dependent toxicity towards osteosarcoma MG-63 cell lines.

Bark extract mediated green synthesis of silver nanoparticles: Evaluation of antimicrobial activity and antiproliferative response against osteosarcoma

International Nuclear Information System (INIS)

Nayak, Debasis; Ashe, Sarbani; Rauta, Pradipta Ranjan; Kumari, Manisha; Nayak, Bismita

2016-01-01

In the current investigation we report the biosynthesis potentials of bark extracts of Ficus benghalensis and Azadirachta indica for production of silver nanoparticle without use of any external reducing or capping agent. The appearance of dark brown color indicated the complete nanoparticle synthesis which was further validated by absorbance peak by UV–vis spectroscopy. The morphology of the synthesized particles was characterized by Field emission- scanning electron microscopy (Fe-SEM) and atomic force microscopy (AFM). The X-ray diffraction (XRD) patterns clearly illustrated the crystalline phase of the synthesized nanoparticles. ATR-Fourier Transform Infrared (ATR-FTIR) spectroscopy was performed to identify the role of various functional groups in the nanoparticle synthesis. The synthesized nanoparticles showed promising antimicrobial activity against Gram negative (Escherichia coli, Pseudomonas aeruginosa and Vibrio cholerae) and Gram positive (Bacillus subtilis) bacteria. The synthesized nano Ag also showed antiproliferative activity against MG-63 osteosarcoma cell line in a dose dependent manner. Thus, these synthesized Ag nanoparticles can be used as a broad spectrum therapeutic agent against osteosarcoma and microorganisms. - Highlights: • Rapid, cost effective, benign synthesis of AgNPs using novel bark extracts • Color change and absorbance peak observed at 426 and 420 nm due to SPR phenomenon • Crystalline and spherical nanoparticles having average size of ~ 40 and ~ 50 nm each • Highly enhanced antimicrobial activity against human nosocomial strains • Demonstrated dose dependent toxicity towards osteosarcoma MG-63 cell lines

Entrapment of curcumin into monoolein-based liquid crystalline nanoparticle dispersion for enhancement of stability and anticancer activity

Science.gov (United States)

Baskaran, Rengarajan; Madheswaran, Thiagarajan; Sundaramoorthy, Pasupathi; Kim, Hwan Mook; Yoo, Bong Kyu

2014-01-01

Despite the promising anticancer potential of curcumin, its therapeutic application has been limited, owing to its poor solubility, bioavailability, and chemical fragility. Therefore, various formulation approaches have been attempted to address these problems. In this study, we entrapped curcumin into monoolein (MO)-based liquid crystalline nanoparticles (LCNs) and evaluated the physicochemical properties and anticancer activity of the LCN dispersion. The results revealed that particles in the curcumin-loaded LCN dispersion were discrete and monodispersed, and that the entrapment efficiency was almost 100%. The stability of curcumin in the dispersion was surprisingly enhanced (about 75% of the curcumin survived after 45 days of storage at 40°C), and the in vitro release of curcumin was sustained (10% or less over 15 days). Fluorescence-activated cell sorting (FACS) analysis using a human colon cancer cell line (HCT116) exhibited 99.1% fluorescence gating for 5 μM curcumin-loaded LCN dispersion compared to 1.36% for the same concentration of the drug in dimethyl sulfoxide (DMSO), indicating markedly enhanced cellular uptake. Consistent with the enhanced cellular uptake of curcumin-loaded LCNs, anticancer activity and cell cycle studies demonstrated apoptosis induction when the cells were treated with the LCN dispersion; however, there was neither noticeable cell death nor significant changes in the cell cycle for the same concentration of the drug in DMSO. In conclusion, entrapping curcumin into MO-based LCNs may provide, in the future, a strategy for overcoming the hurdles associated with both the stability and cellular uptake issues of the drug in the treatment of various cancers. PMID:25061290

Green biosynthesis of silver nanoparticles using pomegranate peel and inhibitory effects of the nanoparticles on aflatoxin production

International Nuclear Information System (INIS)

Monira, A.O.; Mohammad, M.A.; Ashraf, H.A.

2017-01-01

In this work, pomegranate peel has been used as a natural and safe method for biosynthesis of silver nanoparticles. The synthesis of silver nanoparticles was confirmed using UV spectroscopy, which showed a peak around a wavelength of 437 nm. The morphology showed spherical and monodispersed nanoparticles with a size range between 5-50 nm. Using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), X-ray diffraction (XRD) experiments revealed their crystalline nature. Active functional groups in the synthesized silver nanoparticles were determined using Fourier transform infrared (FTIR) spectrometers contained four bands at 3281.21 cm/sup -1/, possibly indicating the participationof O-H functional group. The peak take place at 1,636.22 cm/sup -1/ may be pointed to C = N bending in the amide group or C = O stretching in carboxyl. Transfer in this peak (from 1,641 to 1,643 cm/sup -1/) shown the possible role of amino groups or carboxyl in nanoparticle synthesis. The peaks at 431.95 and 421.28 cm/sup -1/ be related to AgNPs bonding with oxygen from hydroxyl groups which confirm the role of pomegranate peel as a reducing agent. Furthermore, we investigated effects of these nanoparticles on aflatoxin B1 production by the fungus Aspergillus flavus, isolated from hazelnut. The results found that aflatoxin production in all A. flavus isolates decreased with an increase in the concentration of silver nanoparticles. Maximum suppression of aflatoxin production was recorded at a nanoparticle concentration of 150 ppm. (author)

Photocatalytic activity of biogenic silver nanoparticles synthesized using potato (Solanum tuberosum) infusion.

Science.gov (United States)

Roy, Kaushik; Sarkar, C K; Ghosh, C K

2015-07-05

In this study, we have reported a fast and eco-benign procedure to synthesis silver nanoparticle at room temperature using potato (Solanum tuberosum) infusion along with the study of its photocatalytic activity on methyl orange dye. After addition of potato infusion to silver nitrate solution, the color of the mixture changed indicating formation of silver nanoparticles. Time dependent UV-Vis spectra were obtained to study the rate of nanoparticle formation with time. Purity and crystallinity of the biogenic silver nanoparticles were examined by X-ray diffraction (XRD). Average size and morphology of the nanoparticles were characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). Fourier transform infra-red spectroscopy (FTIR) was employed to detect functional bio-molecules responsible that contribute to the reduction and capping of biosynthesized Ag nanoparticles. Further, these synthesized nanoparticles were used to investigate their ability to degrade methyl orange dye under sunlight irradiation and the results showed effective photocatalytic property of these biogenic silver nanoparticles. Copyright © 2015 Elsevier B.V. All rights reserved.

Rapid synthesis of flower shaped Cu_2ZnSnS_4 nanoparticles by microwave irradiation for solar cell application

International Nuclear Information System (INIS)

Ansari, Mohd Zubair; Khare, Neeraj

2016-01-01

Single phase Cu_2ZnSnS__4 (CZTS) nanoparticles have been synthesized by the microwave-assisted solution method in a one step process. Structural, morphological and optical characterizations of the CZTS nanoparticles have been carried out. X-ray diffraction confirms the single phase formation of CZTS nanoparticles with kesterite structure. SEM confirms the homogenous distribution of CZTS nanoparticles flower like assemblies. High resolution TEM image confirms the good crystallinity of the CZTS nanoparticles with the average grain size ~20 nm. The CZTS nanoparticles have strong optical absorption in the visible region with direct band gap as ~1.6 eV which is optimal for photovoltaic application

Beneficial effects of microwave-assisted heating versus conventional heating in noble metal nanoparticle synthesis.

Science.gov (United States)

Dahal, Naween; García, Stephany; Zhou, Jiping; Humphrey, Simon M

2012-11-27

An extensive comparative study of the effects of microwave versus conventional heating on the nucleation and growth of near-monodisperse Rh, Pd, and Pt nanoparticles has revealed distinct and preferential effects of the microwave heating method. A one-pot synthetic method has been investigated, which combines nucleation and growth in a single reaction via precise control over the precursor addition rate. Using this method, microwave-assisted heating enables the convenient preparation of polymer-capped nanoparticles with improved monodispersity, morphological control, and higher crystallinity, compared with samples heated conventionally under otherwise identical conditions. Extensive studies of Rh nanoparticle formation reveal fundamental differences during the nucleation phase that is directly dependent on the heating method; microwave irradiation was found to provide more uniform seeds for the subsequent growth of larger nanostructures of desired size and surface structure. Nanoparticle growth kinetics are also markedly different under microwave heating. While conventional heating generally yields particles with mixed morphologies, microwave synthesis consistently provides a majority of tetrahedral particles at intermediate sizes (5-7 nm) or larger cubes (8+ nm) upon further growth. High-resolution transmission electron microscopy indicates that Rh seeds and larger nanoparticles obtained from microwave-assisted synthesis are more highly crystalline and faceted versus their conventionally prepared counterparts. Microwave-prepared Rh nanoparticles also show approximately twice the catalytic activity of similar-sized conventionally prepared particles, as demonstrated in the vapor-phase hydrogenation of cyclohexene. Ligand exchange reactions to replace polymer capping agents with molecular stabilizing agents are also easily facilitated under microwave heating, due to the excitation of polar organic moieties; the ligand exchange proceeds with excellent retention of

Liquid Crystalline Nanoparticles as an Ophthalmic Delivery System for Tetrandrine: Development, Characterization, and In Vitro and In Vivo Evaluation

Science.gov (United States)

Liu, Rui; Wang, Shuangshuang; Fang, Shiming; Wang, Jialu; Chen, Jingjing; Huang, Xingguo; He, Xin; Liu, Changxiao

2016-05-01

The purpose of this study was to develop novel liquid crystalline nanoparticles (LCNPs) that display improved pre-ocular residence time and ocular bioavailability and that can be used as an ophthalmic delivery system for tetrandrine (TET). The delivery system consisted of three primary components, including glyceryl monoolein, poloxamer 407, and water, and two secondary components, including Gelucire 44/14 and amphipathic octadecyl-quaternized carboxymethyl chitosan. The amount of TET, the amount of glyceryl monoolein, and the ratio of poloxamer 407 to glyceryl monoolein were selected as the factors that were used to optimize the dependent variables, which included encapsulation efficiency and drug loading. A three-factor, five-level central composite design was constructed to optimize the formulation. TET-loaded LCNPs (TET-LCNPs) were characterized to determine their particle size, zeta potential, entrapment efficiency, drug loading capacity, particle morphology, inner crystalline structure, and in vitro drug release profile. Corneal permeation in excised rabbit corneas was evaluated. Pre-ocular retention was determined using a noninvasive fluorescence imaging system. Finally, pharmacokinetic study in the aqueous humor was performed by microdialysis technique. The optimal formulation had a mean particle size of 170.0 ± 13.34 nm, a homogeneous distribution with polydispersity index of 0.166 ± 0.02, a positive surface charge with a zeta potential of 29.3 ± 1.25 mV, a high entrapment efficiency of 95.46 ± 4.13 %, and a drug loading rate of 1.63 ± 0.07 %. Transmission electron microscopy showed spherical particles that had smooth surfaces. Small-angle X-ray scattering profiles revealed an inverted hexagonal phase. The in vitro release assays showed a sustained drug release profile. A corneal permeation study showed that the apparent permeability coefficient of the optimal formulation was 2.03-fold higher than that of the TET solution. Pre-ocular retention

Investigating the growth mechanism and optical properties of carbon-coated titanium dioxide nanoparticles

KAUST Repository

Anjum, Dalaver H.; Memon, Nasir; Chung, Suk-Ho

2013-01-01

TiO2 nanoparticles (NPs) were prepared using flame synthesis and then characterized using transmission electron microscopy. We found that the flame method yields both crystalline TiO2 and amorphous TiO 2 NPs. TEM analysis revealed that only

Fabrication and Characterization of Zinc Sulfide Nanoparticles and Nanocomposites Prepared via a Simple Chemical Precipitation Method

Directory of Open Access Journals (Sweden)

Kambiz Hedayati

2016-07-01

Full Text Available In this research zinc sulfide (ZnS nanoparticles and nanocomposites powders were prepared by chemical precipitation method using zinc acetate and various sulfur sources. The ZnS nanoparticles were characterized by X-ray diffraction, scanning electron microscopy, ultraviolet-visible and fourier transform infra-red. The structure of nanoparticles was studied using X-ray diffraction pattern. The crystallite size of ZnS nanoparticles was calculated by Debye–Scherrer formula. Morphology of nano-crystals was observed and investigated using the scanning electron microscopy. The grain size of zinc sulfide nanoparticles were in suitable agreement with the crystalline size calculated by X-ray diffraction results. The optical properties of particles were studied with ultraviolet-visible absorption spectrum.

Simple synthetic route for hydroxyapatite colloidal nanoparticles via a Nd:YAG laser ablation in liquid medium

Science.gov (United States)

Mhin, Sung Wook; Ryu, Jeong Ho; Kim, Kang Min; Park, Gyeong Seon; Ryu, Han Wool; Shim, Kwang Bo; Sasaki, Takeshi; Koshizaki, Naoto

2009-08-01

Pulsed laser ablation (PLA) in liquid medium was successfully employed to synthesize hydroxyapatite (HAp) colloidal nanoparticles. The crystalline phase, particle morphology, size distribution and microstructure of the HAp nanoparticles were investigated in detail. The obtained HAp nanoparticles had spherical shape with sizes ranging from 5 to 20 nm. The laser ablation and the nanoparticle forming process were studied in terms of the explosive ejection mechanism by investigating the change of the surface morphology on target. The stoichiometry and bonding properties were studied by using XPS, FT-IR and Raman spectroscopy. A molar ratio of Ca/P of the prepared HAp nanoparticles was more stoichiometric than the value reported in the case of ablation in vacuum.

Reactor Materials Program electrochemical potential measurements by ORNL with unirradiated and irradiated stainless steel specimens

Energy Technology Data Exchange (ETDEWEB)

Baumann, E.W.; Caskey, G.R. Jr.

1993-07-01

Effect of irradiation of stainless steel on electrochemical potential (ECP) was investigated by measurements in dilute HNO{sub 3} and H{sub 2}O{sub 2} solutions, conditions simulating reactor moderator. The electrodes were made from unirradiated/irradiated, unsensitized/sensitized specimens from R-reactor piping. Results were inconclusive because of budgetary restrictions. The dose rate may have been too small to produce a significant radiolytic effect. Neither the earlier CERT corrosion susceptibility tests nor the present ECP measurements showed a pronounced effect of irradiation on susceptibility of the stainless steel to IGSCC; this is confirmed by the absence in the stainless steel of the SRS reactor tanks (except for the C Reactor tank knuckle area).

Reactor Materials Program electrochemical potential measurements by ORNL with unirradiated and irradiated stainless steel specimens

International Nuclear Information System (INIS)

Baumann, E.W.; Caskey, G.R. Jr.

1993-07-01

Effect of irradiation of stainless steel on electrochemical potential (ECP) was investigated by measurements in dilute HNO 3 and H 2 O 2 solutions, conditions simulating reactor moderator. The electrodes were made from unirradiated/irradiated, unsensitized/sensitized specimens from R-reactor piping. Results were inconclusive because of budgetary restrictions. The dose rate may have been too small to produce a significant radiolytic effect. Neither the earlier CERT corrosion susceptibility tests nor the present ECP measurements showed a pronounced effect of irradiation on susceptibility of the stainless steel to IGSCC; this is confirmed by the absence in the stainless steel of the SRS reactor tanks (except for the C Reactor tank knuckle area)

Synthesis of functionalized magnetite nanoparticles to use as liver targeting MRI contrast agent

International Nuclear Information System (INIS)

Yazdani, Farshad; Fattahi, Bahare; Azizi, Najmodin

2016-01-01

The aim of this research was the preparation of functionalized magnetite nanoparticles to use as a liver targeting contrast agent in magnetic resonance imaging (MRI). For this purpose, Fe_3O_4 nanoparticles were synthesized via the co-precipitation method. The synthesized nanoparticles were coated with silica via the Stober method and finally the coated nanoparticles were functionalized with mebrofenin. Formation of crystalline magnetite particles was confirmed by X-ray diffraction (XRD) analysis. The Fourier transform infrared spectroscopy (FTIR) and energy dispersive X-ray analyzer (EDX) of the final product showed that silica had been effectively bonded onto the surface of the magnetite nanoparticles and the coated nanoparticles functionalized with mebrofenin. The magnetic resonance imaging of the functional nanoparticles showed that the Fe_3O_4–SiO_2-mebrofenin composite is an effective MRI contrast agent for liver targeting. - Highlights: • Superparamagnetic magnetite nanoparticles have been synthesized by simple and economical method. • Preperation of functional MNPs as a MRI contrast agent for liver targeting. • Gaining a good r_2 relaxivity of the coated functional nanoparticles.

Superparamagnetism in AFM Cr2O3 nanoparticles

International Nuclear Information System (INIS)

Tobia, D.; Winkler, E.L.; Zysler, R.D.; Granada, M.; Troiani, H.E.

2010-01-01

In this work we report the size effects on the magnetic properties of AFM Cr 2 O 3 nanoparticles. From transmission electron microscopy we determined that the system presents high crystallinity and narrow lognormal size distribution centred at = 7.8 nm with σ = 0.3. The magnetic properties of the nanoparticles were studied by magnetization and electron paramagnetic resonance (EPR) experiments. By EPR spectroscopy we established that the AFM order temperature, T N , shifted to ∼270 K when the size is reduced (T N (Bulk) ∼ 308 K). From the zero-field-cooling and the field-cooling magnetization curves we determined the blocking temperature T B = 28 K. Below T B the system presents exchange bias effect. We discuss the results by using recent models in terms of the internal magnetic structures of the nanoparticles.

Zn nanoparticle formation in FIB irradiated single crystal ZnO

Science.gov (United States)

Pea, M.; Barucca, G.; Notargiacomo, A.; Di Gaspare, L.; Mussi, V.

2018-03-01

We report on the formation of Zn nanoparticles induced by Ga+ focused ion beam on single crystal ZnO. The irradiated materials have been studied as a function of the ion dose by means of atomic force microscopy, scanning electron microscopy, Raman spectroscopy and transmission electron microscopy, evidencing the presence of Zn nanoparticles with size of the order of 5-30 nm. The nanoparticles are found to be embedded in a shallow amorphous ZnO matrix few tens of nanometers thick. Results reveal that ion beam induced Zn clustering occurs producing crystalline particles with the same hexagonal lattice and orientation of the substrate, and could explain the alteration of optical and electrical properties found for FIB fabricated and processed ZnO based devices.

Extracellular biosynthesis of gold and silver nanoparticles using Krishna tulsi ( Ocimum sanctum) leaf

Science.gov (United States)

Philip, Daizy; Unni, C.

2011-05-01

Aqueous extract of Ocimum sanctum leaf is used as reducing agent for the environmentally friendly synthesis of gold and silver nanoparticles. The nanoparticles were characterized using UV-vis, transmission electron microscopy (TEM), X-ray diffraction (XRD) and FTIR analysis. These methods allow the synthesis of hexagonal gold nanoparticles having size ∼30 nm showing two surface plasmon resonance (SPR) bands by changing the relative concentration of HAuCl 4 and the extract. Broadening of SPR is observed at larger quantities of the extract possibly due to biosorption of gold ions. Silver nanoparticles with size in the range 10-20 nm having symmetric SPR band centered around 409 nm are obtained for the colloid synthesized at room temperature at a pH of 8. Crystallinity of the nanoparticles is confirmed from the XRD pattern. Biomolecules responsible for capping are different in gold and silver nanoparticles as evidenced by the FTIR spectra.

ZrO2 nanoparticles' effects on split tensile strength of self compacting concrete

Directory of Open Access Journals (Sweden)

Ali Nazari

2010-12-01

Full Text Available In the present study, split tensile strength of self compacting concrete with different amount of ZrO2 nanoparticles has been investigated. ZrO2 nanoparticles with the average particle size of 15 nm were added partially to cement paste (Portland cement together with polycarboxylate superplasticizer and split tensile strength of the specimens has been measured. The results indicate that ZrO2 nanoparticles are able to improve split tensile strength of concrete and recover the negative effects of polycarboxylate superplasticizer. ZrO2 nanoparticle as a partial replacement of cement up to 4 wt. (% could accelerate C-S-H gel formation as a result of increased crystalline Ca(OH2 amount at the early age of hydration. The increased the ZrO2 nanoparticles' content more than 4 wt. (%, causes the reduced the split tensile strength because of unsuitable dispersion of nanoparticles in the concrete matrix.

Room temperature inorganic polycondensation of oxide (Cu2O and ZnO) nanoparticles and thin films preparation by the dip-coating technique

OpenAIRE

Salek, Guillaume; Tenailleau, Christophe; Dufour, Pascal; Guillemet-Fritsch, Sophie

2015-01-01

International audience; Oxide thin solid filmswere prepared by dip-coating into colloidal dispersions of oxide nanoparticles stabilized at room temperaturewithout the use of chelating or complex organic dispersing agents. Crystalline oxide nanoparticles were obtained by inorganic polycondensation and characterized by X-ray diffraction and field emission gun scanning electron microscopy. Water and ethanol synthesis and solution stabilization of oxide nanoparticle method was optimized to prepar...

Structural transformations of mechanically induced top-down approach BaFe{sub 12}O{sub 19} nanoparticles synthesized from high crystallinity bulk materials

Energy Technology Data Exchange (ETDEWEB)

Low, Zhi Huang [Institute of Advanced Technology, Universiti Putra Malaysia, 43400 Serdang, Selangor Darul Ehsan (Malaysia); Chen, Soo Kien [Institute of Advanced Technology, Universiti Putra Malaysia, 43400 Serdang, Selangor Darul Ehsan (Malaysia); Department of Physics, Faculty of Science, University Putra Malaysia, 43400 Serdang, Selangor Darul Ehsan (Malaysia); Ismail, Ismayadi, E-mail: kayzen@gmail.com [Institute of Advanced Technology, Universiti Putra Malaysia, 43400 Serdang, Selangor Darul Ehsan (Malaysia); Tan, Kim Song [Advanced Imaging Centre, Malaysian Rubber Board, RRIM Sungai Buloh, 47000 Selangor (Malaysia); Liew, J.Y.C. [Department of Physics, Faculty of Science, University Putra Malaysia, 43400 Serdang, Selangor Darul Ehsan (Malaysia)

2017-05-01

In this work, a top-down approach was applied to high crystallinity BaFe{sub 12}O{sub 19} bulks, breaking them into smaller nanoparticles by mechanochemical route. The effects of milling time, reaction mechanisms and structural information were investigated. Interestingly, three distinct stages of the mechanochemical mechanism were observed. The XRD results indicated that the BaFe{sub 12}O{sub 19} phase existed even though the mechanical energy had induced the formation of an amorphous phase in the material. The average crystallite size decreased during the first stage and the intermediate stage, and increased during the final stage of the mechanical alloying. A Rietveld refinement analysis suggested the deformation of a mechanically-triggered polyhedral in the magnetoplumbite structure. FESEM micrographs indicated that fragmentation predominated during the first and intermediate stages, until a steady equilibrium state was achieved at in the final stage, where a narrow particle size distribution was observed. HRTEM micrographs suggested the formation of a non-uniform nanostructure shell surrounding the ordered core materials at the edge-interface region. The thickness of the amorphous surface layer extended up to 12 nm during the first and intermediate stages, and diminished to approximately 3 nm after 20 h milling. VSM results showed a mixture of ferromagnetic, superparamagnetic, and paramagnetic behaviours. However, different magnetic behaviours predominated at different milling time, which strongly related to the defects, distorted polyhedra, and non-equilibrium amorphous layers of the material. - Highlights: • Nanoparticles of BaFe{sub 12}O{sub 19} are successfully prepared. • Morphological and structural properties rely on mechanochemical mechanism. • Three stages of mechanochemical mechanism was observed. • Core shell structures (3–12 nm) was found during by extending the milling time. • Magnetic properties were strongly related with the

Influence of Irradiation Time on properties of CdS Nanoparticles Synthesized using Microwave Irradiation

International Nuclear Information System (INIS)

Nayereh Soltani; Elias SSaion; Maryam Erfani; Mohd Zobir Hussein; Robiah Yunus

2011-01-01

Different sizes of cadmium sulfide nanoparticles which exhibit obvious quantum confinement effect have been synthesized of cadmium chloride and thioacetamide through the simple and rapid microwave method. The properties of these CdS nanoparticles were examined with varying irradiation time from 10 to 40 min using a pulse regime. The obtained CdS particles were characterized by X-ray diffraction (XRD), transition electron microscopy (TEM) and UV-visible (UV-Vis) spectroscopy. The effects of irradiation time on the size, degree of crystallinity, yield of reaction and optical band gap of CdS nanoparticles are investigated. (author)

Surface modifications caused by a swift heavy ion irradiation on crystalline p-type gallium antimonide

Energy Technology Data Exchange (ETDEWEB)

Jadhav, Vidya, E-mail: vj1510@yahoo.com

2015-09-01

Surface modifications caused by a swift heavy ion irradiation on crystalline p-type gallium antimonide crystal have been reported. Single crystal, 1 0 0〉 orientations and ∼500 μm thick p-type GaSb samples with carrier concentration of 3.30 × 10{sup 17} cm{sup −3} were irradiated at 100 MeV Fe{sup 7+} ions. We have used 15UD Pelletron facilities at IUAC with varying fluences of 5 × 10{sup 10}–1 × 10{sup 14} ions cm{sup −2}. The effects of irradiation on these samples have been investigated using, spectroscopic ellipsometry, atomic force microscopy and ultraviolet–visible–NIR spectroscopy techniques. Ellipsometry parameters, psi (Ψ) and delta (Δ) for the unirradiated sample and samples irradiated with different fluences were recorded. The data were fit to a three phase model to determine the refractive index and extinction coefficient. The refractive index and extinction coefficient for various fluences in ultraviolet, visible, and infrared, regimes were evaluated. Atomic force microscopy has been used to study these surface modifications. In order to have more statistical information about the surface, we have plotted the height structure histogram for all the samples. For unirradiated sample, we observed the Gaussian fitting. This result indicates the more ordered height structure symmetry. Whereas for the sample irradiated with the fluence of 1 × 10{sup 13}, 5 × 10{sup 13} and 1 × 10{sup 14} ions cm{sup −2}, we observed the scattered data. The width of the histogram for samples irradiated up to the fluence of 1 × 10{sup 13} ion cm{sup −2} was found to be almost same however it decreased at higher fluence. UV reflectance spectra of the sample irradiated with increasing fluences exhibit three peaks at 292, 500 and 617 nm represent the high energy GaSb; E{sub 1}, E{sub 1} + Δ and E{sub 2} band gaps in all irradiated samples.

Surface modifications caused by a swift heavy ion irradiation on crystalline p-type gallium antimonide

International Nuclear Information System (INIS)

Jadhav, Vidya

2015-01-01

Surface modifications caused by a swift heavy ion irradiation on crystalline p-type gallium antimonide crystal have been reported. Single crystal, 1 0 0〉 orientations and ∼500 μm thick p-type GaSb samples with carrier concentration of 3.30 × 10 17 cm −3 were irradiated at 100 MeV Fe 7+ ions. We have used 15UD Pelletron facilities at IUAC with varying fluences of 5 × 10 10 –1 × 10 14 ions cm −2 . The effects of irradiation on these samples have been investigated using, spectroscopic ellipsometry, atomic force microscopy and ultraviolet–visible–NIR spectroscopy techniques. Ellipsometry parameters, psi (Ψ) and delta (Δ) for the unirradiated sample and samples irradiated with different fluences were recorded. The data were fit to a three phase model to determine the refractive index and extinction coefficient. The refractive index and extinction coefficient for various fluences in ultraviolet, visible, and infrared, regimes were evaluated. Atomic force microscopy has been used to study these surface modifications. In order to have more statistical information about the surface, we have plotted the height structure histogram for all the samples. For unirradiated sample, we observed the Gaussian fitting. This result indicates the more ordered height structure symmetry. Whereas for the sample irradiated with the fluence of 1 × 10 13 , 5 × 10 13 and 1 × 10 14 ions cm −2 , we observed the scattered data. The width of the histogram for samples irradiated up to the fluence of 1 × 10 13 ion cm −2 was found to be almost same however it decreased at higher fluence. UV reflectance spectra of the sample irradiated with increasing fluences exhibit three peaks at 292, 500 and 617 nm represent the high energy GaSb; E 1 , E 1 + Δ and E 2 band gaps in all irradiated samples

Flash NanoPrecipitation (FNP) for bioengineering nanoparticles to enhance the bioavailability

Science.gov (United States)

Feng, Jie; Zhang, Yingyue; McManus, Simone; Prud'Homme, Robert

2017-11-01

Nanoparticles for the delivery of therapeutics have been one of the successful areas in biomedical nanotechnology. Nanoparticles improve bioavailability by 1) the higher surface-to-volume ratios, enhancing dissolution rates, and 2) trapping drug molecules in higher energy, amorphous states for a higher solubility. However, conventional direct precipitation to prepare nanoparticles has the issues of low loading and encapsulation efficiency. Here we demonstrate a kinetically controlled and rapid-precipitation process called Flash NanoPrecipitation (FNP), to offer a multi-phase mixing platform for bioengineering nanoparticles. With the designed geometry in the micro-mixer, we can generate nanoparticles with a narrow size distribution, while maintaining high loading and encapsulation efficiency. By controlling the time scales in FNP, we can tune the nanoparticle size and the robustness of the process. Remarkably, the dissolution rates of the nanoparticles are significantly improved compared with crystalline drug powders. Furthermore, we investigate how to recover the drug-loaded nanoparticles from the aqueous dispersions. Regarding the maintenance of the bioavailability, we discuss the advantages and disadvantages of each drying process. These results suggest that FNP offers a versatile and scalable nano-fabrication platform for biomedical engineering.

Silver nanoparticles: Large scale solvothermal synthesis and optical properties

Energy Technology Data Exchange (ETDEWEB)

Wani, Irshad A.; Khatoon, Sarvari [Nanochemistry Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi 110025 (India); Ganguly, Aparna [Nanochemistry Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi 110025 (India); Department of Chemistry, Indian Institute of Technology, Hauz Khas, New Delhi 110016 (India); Ahmed, Jahangeer; Ganguli, Ashok K. [Department of Chemistry, Indian Institute of Technology, Hauz Khas, New Delhi 110016 (India); Ahmad, Tokeer, E-mail: tokeer.ch@jmi.ac.in [Nanochemistry Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi 110025 (India)

2010-08-15

Silver nanoparticles have been successfully synthesized by a simple and modified solvothermal method at large scale using ethanol as the refluxing solvent and NaBH{sub 4} as reducing agent. The nanopowder was investigated by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering (DLS), UV-visible and BET surface area studies. XRD studies reveal the monophasic nature of these highly crystalline silver nanoparticles. Transmission electron microscopic studies show the monodisperse and highly uniform nanoparticles of silver of the particle size of 5 nm, however, the size is found to be 7 nm using dynamic light scattering which is in good agreement with the TEM and X-ray line broadening studies. The surface area was found to be 34.5 m{sup 2}/g. UV-visible studies show the absorption band at {approx}425 nm due to surface plasmon resonance. The percentage yield of silver nanoparticles was found to be as high as 98.5%.

Application of fire-retardant treatment to the wood in Type A unirradiated nuclear fuel outer containers

International Nuclear Information System (INIS)

Whitlow, J.D.; Luna, R.E.

1992-01-01

Packagings for transporting unirradiated nuclear fuel assemblies in the United States are commonly constructed as rectangular boxes consisting of a metal inner container, a wooden outer container, and cushioning material separating the two. The wood in the outer container is a potential source of fuel for fire. Use of a fire-retardant treatment on the wood may reduce or eliminate the damage to nuclear fuel assemblies in some types of accidents involving fire. The applicability of using fire-retardant treatments on the wood of outer containers is addressed. An approximate cost-benefit analysis to determine if fire-retardant treatments are economically justified is presented. (Author)

Studies on extracellular biosynthesis of silver nanoparticles by the fungus aspergillus niger

International Nuclear Information System (INIS)

Ibrahim, H.M.M.

2011-01-01

An eco-friendly process for the synthesis of silver nanoparticles has been attempted, using the culture filtrate of various microorganisms, included bacteria, fungi and yeast. Only fungi, especially aspergillus niger, were capable of synthesizing silver nanoparticles. The culture filtrate treated with AgNo 3 (1 mM) turned dark brown after 72 h of incubation, indicating reduction of silver ions into silver nanoparticles. This observation was confirmed with UV-vis spectroscopy analysis;a large broad band with long tail was detected at 430 nm,this band is characteristic of several metal nanoparticles.X ray diffraction revealed the crystalline nature of obtained nanoparticles. The TEM and SEM analysis showed particles spherical in shape. The average particles size determined by DLS analysis was 94.2 nm.EDX analysis indicated the presence of silver element in the nanoparticles. FT-IR analysis confirmed the presence of protein associated with the synthesized silver nanoparticles. The maximum biosynthesis of nanoparticles was achieved when the culture filtrate was treated with 4.0 mM of AgNo 3 , adjusted to ph 8.0, and incubated at 50 degree C for 96 h. Silver nanoparticles showed antibiotic activity exceeding that of silver ions against various microorganisms

Programmable Self-assembly of Hydrocarbon-capped Nanoparticles: Role of Chain Conformations

Science.gov (United States)

Waltmann, Curt; Horst, Nathan; Travesset, Alex

Nanoparticle superlattices (NPS), i.e. crystalline arrangements of nanoparticles, are materials with fascinating structures, which in many cases are not possible to attain from simple atoms or molecules. They also span a wide range of possible applications such as metamaterials, new energy sources, catalysis, and many others. In this talk, we present a theoretical and computational description of the self-assembly of nanoparticles with hydrocarbons as capping ligands. Usually, these systems have been described with hard sphere packing models. In this talk, we show that the conformations of the hydrocarbon chains play a fundamental role in determining the equilibrium phases, including and especially in binary systems. The work of CW was supported by a DOE-SULI internship from May-December 2016, and by NSF, DMR-CMMT 1606336 CDS&E: Design Principles for Ordering Nanoparticles into Super-crystals after January 1st.

Effect of nanoparticle and aggregate size on the relaxometric properties of MR contrast agents based on high quality magnetite nanoparticles.

Science.gov (United States)

Roca, Alejandro G; Veintemillas-Verdaguer, Sabino; Port, Marc; Robic, Caroline; Serna, Carlos J; Morales, Maria P

2009-05-14

Colloidal dispersions of monodispersed and high-crystalline magnetite nanoparticles have been used to establish a relationship between magnetic properties and magnetic resonance (MR) relaxometric parameters in vitro. Magnetite nanoparticles with diameters between 4 and 14 nm were synthesized by thermal decomposition of Fe(acac)3 in different organic solvents and transformed to hydrophilic by changing oleic acid for dimercaptosuccinic acid (DMSA). A final treatment in alkaline water was critical to make the suspension stable at pH 7 with xi-potential values of -45 mV and hydrodynamic sizes as low as 50 nm. Samples showed superparamagnetic behavior at room temperature, which is an important parameter for biomedical applications. Susceptibility increased with both particle and aggregate size, and for particles larger than 9 nm, the aggregate size was the key factor controlling the susceptibility. Relaxivity values followed the same trend as the suspension susceptibilities, indicating that the aggregate size is an important factor above a certain particle size governing the proton relaxation times. The highest relaxivity value, r2=317 s(-1) mM(-1), much higher than those for commercial contrast agents with similar hydrodynamic size, was obtained for a suspension consisting of 9 nm particles and 70 nm of hydrodynamic size, and it was assigned to the higher particle crystallinity in comparison to particles prepared by coprecipitation. Therefore, it can be concluded that in addition to the sample crystallinity, both particle size and aggregate size should be considered in order to explain the magnetic and relaxivity values of a suspension.

Microwave-hydrothermal synthesis of barium strontium titanate nanoparticles

International Nuclear Information System (INIS)

Simoes, A.Z.; Moura, F.; Onofre, T.B.; Ramirez, M.A.; Varela, J.A.; Longo, E.

2010-01-01

Research highlights: → Barium strontium titanate nanoparticles were obtained by the Hydrothemal microwave technique (HTMW) → This is a genuine technique to obtain nanoparticles at low temperature and short times → Barium strontium titanate free of carbonates with tetragonal structure was grown at 130 o C. - Abstract: Hydrothermal-microwave method (HTMW) was used to synthesize crystalline barium strontium titanate (Ba 0.8 Sr 0.2 TiO 3 ) nanoparticles (BST) in the temperature range of 100-130 o C. The crystallization of BST with tetragonal structure was reached at all the synthesis temperatures along with the formation of BaCO 3 as a minor impurity at lower syntheses temperatures. Typical FT-IR spectra for tetragonal (BST) nanoparticles presented well defined bands, indicating a substantial short-range order in the system. TG-DTA analyses confirmed the presence of lattice OH- groups, commonly found in materials obtained by HTMW process. FE/SEM revealed that lower syntheses temperatures led to a morphology that consisted of uniform grains while higher syntheses temperature consisted of big grains isolated and embedded in a matrix of small grains. TEM has shown BST nanoparticles with diameters between 40 and 80 nm. These results show that the HTMW synthesis route is rapid, cost effective, and could serve as an alternative to obtain BST nanoparticles.

Extracellular mycosynthesis of gold nanoparticles using Fusarium solani

Science.gov (United States)

Gopinath, K.; Arumugam, A.

2014-08-01

The development of eco-friendly methods for the synthesis of nanomaterial shape and size is an important area of research in the field of nanotechnology. The present investigation deals with the extracellular rapid biosynthesis of gold nanoparticles using Fusarium solani culture filtrate. The UV-vis spectra of the fungal culture filtrate medium containing gold ion showed peak at 527 nm corresponding to the plasmon absorbance of gold nanoparticles. FTIR spectra provide an evidence for the presence of heterocyclic compound in the culture filtrate, which increases the stability of the synthesized gold nanoparticles. The X-ray analysis respects the Bragg's law and confirmed the crystalline nature of the gold nanoparticles. AFM analysis showed the results of particle sizes (41 nm). Transmission electron microscopy (TEM) showed that the gold nanoparticles are spherical in shape with the size range from 20 to 50 nm. The use of F. solani will offer several advantages since it is considered as a non-human pathogenic organism. The fungus F. solani has a fast growth rate, rapid capacity of metallic ions reduction, NPs stabilization and facile and economical biomass handling. Extracellular biosynthesis of gold nanoparticles could be highly advantageous from the point of view of synthesis in large quantities, time consumption, eco-friendly, non-toxic and easy downstream processing.

EVA/TiO2 nanocomposite: Study of the properties thermal and crystallinity of the EVA/TiO2 nanocomposite

International Nuclear Information System (INIS)

Valentim, Ana C.S.; Tavares, Maria I.B.; Silva, Emerson O. da

2011-01-01

The effect of titanium dioxide nanoparticles on the thermal properties and crystallinity of the ethylene vinyl acetate (EVA) copolymer containing 28% vinyl acetate were investigated. The EVA/TiO 2 nanocomposite films with TiO 2 contents of 0,10-1% relative to the total mass of EVA, were prepared via solution. The prepared films were characterized using TG, and XRD methods. (author)

Kinetics of thermal decomposition of γ-irradiated and unirradiated complexes of mandelhydroxamic acid

International Nuclear Information System (INIS)

Hassan, R.M.; Farid, T.; El-Bellihi, A.A.

1992-01-01

The thermal decomposition of γ-irradiated and unirradiated complexes of mandelhydroxamic acid (HMA), Co (HMA) 2 .1/2H 2 O, Mn (HMA) 2 .2H 2 O, Ba (HMA) 2 .2H 2 O and Cd (HMA) 2 .2H 2 O have been studied thermogravimetrically (under isothermal conditions). The thermal dehydration of each complex occured in one step, while the decomposition of dehydrated complexes occured in two steps. The kinetic parameters for dehydration were computed by different models. The thermal dehydration is regulated by random nucleation A 3 for Co-, Mn-, and Cd-complexes and by phase-boundary (R 3 ) for Ba-complex. The effect of γ-irradiation on the kinetic parameters of thermal decomposition is discussed. Radiation did not modify the mechanism of the reaction but accelarated the dehydration steps in the case of Mn- and Co-complexes. (author) 7 refs.; 1 fig.; 4 tabs

Anthelmintic efficacy of gold nanoparticles derived from a phytopathogenic fungus, Nigrospora oryzae.

Directory of Open Access Journals (Sweden)

Pradip Kumar Kar

Full Text Available Exploring a green chemistry approach, this study brings to the fore, the anthelmintic efficacy of gold nanoparticles, highlighting the plausible usage of myconanotechnology. Gold nanoparticles of ∼6 to ∼18 nm diameter were synthesized by treating the mycelia-free culture filtrate of the phytopathogenic fungus with gold chloride. Their size and morphology were confirmed by UV-Vis spectroscopy, DLS data, AFM and TEM images. The XRD studies reveal a crystalline nature of the nanoparticles, which are in cubic phase. The FTIR spectroscopic studies before and after the formation of nanoparticles show the presence of possible functional groups responsible for the bio-reduction and capping of the synthesized gold nanoparticles. The latter were tested as vermifugal agents against a model cestode Raillietina sp., an intestinal parasite of domestic fowl. Further, ultrastructural and biochemical parameters were used to corroborate the efficacy study.

Flow sheet development for the dissolution of unirradiated Mark 42 fuel tubes in F-Canyon, Part II

International Nuclear Information System (INIS)

Murray, A.M.

1999-01-01

Two dissolution flow sheets were tested for the desorption of unirradiated Mark 42 fuel tubes. Both the aluminum (from the can, cladding, and fuel core) and the plutonium oxide (PuO 2 ) are dissolved simultaneously, i.e., a co-dissolution flow sheet. In the first series of tests, 0.15 and 0.20 molar (M) potassium fluoride (KF) solutions were used and the dissolution extended over several days. In the other series of tests, solutions with higher concentrations of fluoride (0.25 to 0.30 M) were used. Calcium fluoride (CaF 2 ) was used in those tests as the fluoride source

Effect of annealing on properties of Mg doped Zn-ferrite nanoparticles

Directory of Open Access Journals (Sweden)

K. Nadeem

2015-04-01

Full Text Available A comparison of structural and magnetic properties of as-prepared and annealed (900 °C Mg doped Zn ferrite nanoparticles (Zn1−xMgxFe2O4, with x=0, 0.1, 0.2, 0.3, 0.4 and 0.5 is presented. X-ray diffraction (XRD studies confirmed the cubic spinel structure for both the as-prepared and annealed nanoparticles. The average crystallite size and lattice parameter were increased by annealing. Scanning electron microscopy (SEM images also showed that the average particle size increased after annealing. Fourier transform infrared spectroscopy (FTIR also confirmed the spinel structure for both series of nanoparticles. For both annealed and as-prepared nanoparticles, the O–Mtet.–O vibrational band shifts towards higher wave numbers with increased Mg concentration due to cationic rearrangement on the lattice sites. Magnetization studies revealed an anomalous decreasing magnetization for the annealed nanoparticles which is also ascribed to cationic rearrangement on the lattice sites after annealing. The measurement of coercivity showed a decreasing trend by annealing due to the increased nanoparticle size and better crystallinity.

Antifungal activity of gold nanoparticles prepared by solvothermal method

Energy Technology Data Exchange (ETDEWEB)

Ahmad, Tokeer, E-mail: tahmad3@jmi.ac.in [Nanochemistry Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi 110025 (India); Wani, Irshad A.; Lone, Irfan H.; Ganguly, Aparna [Nanochemistry Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi 110025 (India); Manzoor, Nikhat; Ahmad, Aijaz [Department of Biosciences, Jamia Millia Islamia, New Delhi 110025 (India); Ahmed, Jahangeer [Department of Chemistry, Michigan State University, East Lansing, MI 48824 (United States); Al-Shihri, Ayed S. [Department of Chemistry, Faculty of Science, King Khalid University, Abha 61413, P.O. Box 9004 (Saudi Arabia)

2013-01-15

Graphical abstract: Gold nanoparticles (7 and 15 nm) of very high surface area (329 and 269 m{sup 2}/g) have been successfully synthesized through solvothermal method by using tin chloride and sodium borohydride as reducing agents. As-prepared gold nanoparticles shows very excellent antifungal activity against Candida isolates and activity increases with decrease in the particle size. Display Omitted Highlights: ► Effect of reducing agents on the morphology of gold nanoparticles. ► Highly uniform and monodisperse gold nanoparticles (7 nm). ► Highest surface area of gold nanoparticles (329 m{sup 2/}g). ► Excellent antifungal activity of gold nanoparticles against Candida strains. -- Abstract: Gold nanoparticles have been successfully synthesized by solvothermal method using SnCl{sub 2} and NaBH{sub 4} as reducing agents. X-ray diffraction studies show highly crystalline and monophasic nature of the gold nanoparticles with face centred cubic structure. The transmission electron microscopic studies show the formation of nearly spherical gold nanoparticles of average size of 15 nm using SnCl{sub 2}, however, NaBH{sub 4} produced highly uniform, monodispersed and spherical gold nanoparticles of average grain size of 7 nm. A high surface area of 329 m{sup 2}/g for 7 nm and 269 m{sup 2}/g for 15 nm gold nanoparticles was observed. UV–vis studies assert the excitations over the visible region due to transverse and longitudinal surface plasmon modes. The gold nanoparticles exhibit excellent size dependant antifungal activity and greater biocidal action against Candida isolates for 7 nm sized gold nanoparticles restricting the transmembrane H{sup +} efflux of the Candida species than 15 nm sized gold nanoparticles.

Antifungal activity of gold nanoparticles prepared by solvothermal method

International Nuclear Information System (INIS)

Ahmad, Tokeer; Wani, Irshad A.; Lone, Irfan H.; Ganguly, Aparna; Manzoor, Nikhat; Ahmad, Aijaz; Ahmed, Jahangeer; Al-Shihri, Ayed S.

2013-01-01

Graphical abstract: Gold nanoparticles (7 and 15 nm) of very high surface area (329 and 269 m 2 /g) have been successfully synthesized through solvothermal method by using tin chloride and sodium borohydride as reducing agents. As-prepared gold nanoparticles shows very excellent antifungal activity against Candida isolates and activity increases with decrease in the particle size. Display Omitted Highlights: ► Effect of reducing agents on the morphology of gold nanoparticles. ► Highly uniform and monodisperse gold nanoparticles (7 nm). ► Highest surface area of gold nanoparticles (329 m 2/ g). ► Excellent antifungal activity of gold nanoparticles against Candida strains. -- Abstract: Gold nanoparticles have been successfully synthesized by solvothermal method using SnCl 2 and NaBH 4 as reducing agents. X-ray diffraction studies show highly crystalline and monophasic nature of the gold nanoparticles with face centred cubic structure. The transmission electron microscopic studies show the formation of nearly spherical gold nanoparticles of average size of 15 nm using SnCl 2 , however, NaBH 4 produced highly uniform, monodispersed and spherical gold nanoparticles of average grain size of 7 nm. A high surface area of 329 m 2 /g for 7 nm and 269 m 2 /g for 15 nm gold nanoparticles was observed. UV–vis studies assert the excitations over the visible region due to transverse and longitudinal surface plasmon modes. The gold nanoparticles exhibit excellent size dependant antifungal activity and greater biocidal action against Candida isolates for 7 nm sized gold nanoparticles restricting the transmembrane H + efflux of the Candida species than 15 nm sized gold nanoparticles.

Plasmonic and silicon spherical nanoparticle antireflective coatings

Science.gov (United States)

Baryshnikova, K. V.; Petrov, M. I.; Babicheva, V. E.; Belov, P. A.

2016-03-01

Over the last decade, plasmonic antireflecting nanostructures have been extensively studied to be utilized in various optical and optoelectronic systems such as lenses, solar cells, photodetectors, and others. The growing interest to all-dielectric photonics as an alternative optical technology along with plasmonics motivates us to compare antireflective properties of plasmonic and all-dielectric nanoparticle coatings based on silver and crystalline silicon respectively. Our simulation results for spherical nanoparticles array on top of amorphous silicon show that both silicon and silver coatings demonstrate strong antireflective properties in the visible spectral range. For the first time, we show that zero reflectance from the structure with silicon coatings originates from the destructive interference of electric- and magnetic-dipole responses of nanoparticle array with the wave reflected from the substrate, and we refer to this reflection suppression as substrate-mediated Kerker effect. We theoretically compare the silicon and silver coating effectiveness for the thin-film photovoltaic applications. Silver nanoparticles can be more efficient, enabling up to 30% increase of the overall absorbance in semiconductor layer. Nevertheless, silicon coatings allow up to 64% absorbance increase in the narrow band spectral range because of the substrate-mediated Kerker effect, and band position can be effectively tuned by varying the nanoparticles sizes.

Synthesis and characterization of silver-copper core-shell nanoparticles using polyol method for antimicrobial agent

Science.gov (United States)

Hikmah, N.; Idrus, N. F.; Jai, J.; Hadi, A.

2016-06-01

Silver and copper nanoparticles are well-known as the good antimicrobial agent. The nano-size of particles influences in enhancing the antimicrobial activity. This paper discusses the effect of molarity on the microstructure and morphology of silver-copper core-shell nanoparticles prepared by a polyol method. In this study, silver-copper nanoparticles are synthesized through the green approach of polyol method using ethylene glycol (EG) as green solvent and reductant, and polyoxyethylene-(80)-sorbitan monooleate (Tween 80) as a nontoxic stabilizer. The phase and morphology of silver-copper nanoparticles are characterized by X-ray diffraction (XRD) and Field emission scanning electron microscope (FESEM) and Transmission electron microscope (TEM). The results XRD confirm the pure crystalline of silver and copper nanoparticles with face-centered cubic (FCC) structure. FESEM and TEM analysis confirm the existence of Ag and Cu nanoparticles in core-shell shape.

Poorly crystalline hydroxyapatite: A novel adsorbent for enhanced fulvic acid removal from aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Wei, Wei [Department of Environmental Science and Engineering, Nanjing Normal University, Nanjing 210023 (China); Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, Nanjing Normal University, Nanjing 210023 (China); Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023 (China); Yang, Lei; Zhong, Wenhui; Cui, Jing [Department of Environmental Science and Engineering, Nanjing Normal University, Nanjing 210023 (China); Wei, Zhenggui, E-mail: weizhenggui@gmail.com [Department of Environmental Science and Engineering, Nanjing Normal University, Nanjing 210023 (China); Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, Nanjing Normal University, Nanjing 210023 (China); Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023 (China)

2015-03-30

term. Findings of the present work highlight the potential for using poorly crystalline HAP nanoparticles as an effective and recyclable adsorbent for FA removal from aqueous solution.

Magnetically Separable Iron Oxide Nanoparticles: An Efficient and Reusable Catalyst for Imino Diels-Alder Reaction

Energy Technology Data Exchange (ETDEWEB)

Basavegowda, Nagaraj; Mishra, Kanchan; Lee, Yong Rok; Joh, Young-Gull [Yeungnam University, Gyeongsan (Korea, Republic of)

2016-02-15

Iron oxide nanoparticles were synthesized using Saururus chinensis (S. chinensis) leaf extract as a reducing and stabilizing agent via ultrasonication. The size, morphology, crystallinity, elemental composition, weight loss, surface chemical state, and magnetic properties of the synthesized nanoparticles were investigated. The synthe-sized nanoparticles were used as an efficient and recyclable catalyst for the synthesis of a variety of 2-methyl-4-substituted-1,2,3,4-tetrahydroquinoline derivatives by the imino Diels-Alder reaction. After the reaction, the catalyst was recovered by an external magnetic field. The recovered catalyst was then reused in a subsequent reaction under identical conditions. The recycled iron oxide nanoparticles (IONPs) were reused five times with-out any significant loss of catalytic activity.

Magnetically Separable Iron Oxide Nanoparticles: An Efficient and Reusable Catalyst for Imino Diels-Alder Reaction

International Nuclear Information System (INIS)

Basavegowda, Nagaraj; Mishra, Kanchan; Lee, Yong Rok; Joh, Young-Gull

2016-01-01

Iron oxide nanoparticles were synthesized using Saururus chinensis (S. chinensis) leaf extract as a reducing and stabilizing agent via ultrasonication. The size, morphology, crystallinity, elemental composition, weight loss, surface chemical state, and magnetic properties of the synthesized nanoparticles were investigated. The synthe-sized nanoparticles were used as an efficient and recyclable catalyst for the synthesis of a variety of 2-methyl-4-substituted-1,2,3,4-tetrahydroquinoline derivatives by the imino Diels-Alder reaction. After the reaction, the catalyst was recovered by an external magnetic field. The recovered catalyst was then reused in a subsequent reaction under identical conditions. The recycled iron oxide nanoparticles (IONPs) were reused five times with-out any significant loss of catalytic activity.

Facile synthesis of silver nanoparticles and their application in dye degradation

Energy Technology Data Exchange (ETDEWEB)

Joseph, Siby, E-mail: sibyjoseph4@gmail.com [Department of Chemistry, St. George' s College, Aruvithura, Kottayam 686122, Kerala (India); Mathew, Beena, E-mail: beenamscs@gmail.com [School of Chemical Sciences, Mahatma Gandhi University, Kottayam 686560, Kerala (India)

2015-05-15

Graphical abstract: - Highlights: • This synthetic method uses the novel reducing agent hexamine. • The method is simple, fast and environment friendly. • This is a cost-effective method as all materials used are inexpensive and readily available. • The method provides highly stable spherical silver nanoparticles. • The nanoparticles show outstanding catalytic activity in the degradation of organic dyes. - Abstract: The present article reports a simple, facile and eco-friendly method based on microwave irradiation for the synthesis of silver nanoparticles in aqueous medium using starch as stabilizing agent and a new reducing agent namely hexamine. The silver nanoparticles were characterized by UV–vis, FTIR, XRD and HR-TEM analysis. UV–vis spectroscopic studies provided sufficient evidences for the formation of nanoparticles. The role of starch in the synthesis and stabilization of the nanoparticles was obtained from FTIR studies. The XRD and HR-TEM investigations clearly demonstrated the crystalline nature of the nanoparticles. From the TEM images, the silver nanoparticles were found to be spherical and of nearly uniform size with an average diameter of 18.2 ± 0.97 nm. The nanoparticles showed excellent catalytic activity in the degradation of methyl orange and rhodamine B by NaBH{sub 4}.

Facile synthesis of silver nanoparticles and their application in dye degradation

International Nuclear Information System (INIS)

Joseph, Siby; Mathew, Beena

2015-01-01

Graphical abstract: - Highlights: • This synthetic method uses the novel reducing agent hexamine. • The method is simple, fast and environment friendly. • This is a cost-effective method as all materials used are inexpensive and readily available. • The method provides highly stable spherical silver nanoparticles. • The nanoparticles show outstanding catalytic activity in the degradation of organic dyes. - Abstract: The present article reports a simple, facile and eco-friendly method based on microwave irradiation for the synthesis of silver nanoparticles in aqueous medium using starch as stabilizing agent and a new reducing agent namely hexamine. The silver nanoparticles were characterized by UV–vis, FTIR, XRD and HR-TEM analysis. UV–vis spectroscopic studies provided sufficient evidences for the formation of nanoparticles. The role of starch in the synthesis and stabilization of the nanoparticles was obtained from FTIR studies. The XRD and HR-TEM investigations clearly demonstrated the crystalline nature of the nanoparticles. From the TEM images, the silver nanoparticles were found to be spherical and of nearly uniform size with an average diameter of 18.2 ± 0.97 nm. The nanoparticles showed excellent catalytic activity in the degradation of methyl orange and rhodamine B by NaBH 4

Eugenol-loaded chitosan nanoparticles: II. Application in bio-based plastics for active packaging.

Science.gov (United States)

Woranuch, Sarekha; Yoksan, Rangrong

2013-07-25

The aim of the present research was to study the possibility of using eugenol-loaded chitosan nanoparticles as antioxidants for active bio-based packaging material. Eugenol-loaded chitosan nanoparticles were incorporated into thermoplastic flour (TPF) - a model bio-based plastic - through an extrusion process at temperatures above 150°C. The influences of eugenol-loaded chitosan nanoparticles on crystallinity, morphology, thermal properties, radical scavenging activity, reducing power, tensile properties and barrier properties of TPF were investigated. Although the incorporation of 3% (w/w) of eugenol-loaded chitosan nanoparticles significantly reduced the extensibility and the oxygen barrier property of TPF, it provided antioxidant activity and improved the water vapor barrier property. In addition, TPF containing eugenol-loaded chitosan nanoparticles exhibited superior radical scavenging activity and stronger reducing power compared with TPF containing naked eugenol. The results suggest the applicability of TPF containing eugenol-loaded chitosan nanoparticles as an antioxidant active packaging material. Copyright © 2012 Elsevier Ltd. All rights reserved.

Rapid synthesis of flower shaped Cu{sub 2}ZnSnS{sub 4} nanoparticles by microwave irradiation for solar cell application

Energy Technology Data Exchange (ETDEWEB)

Ansari, Mohd Zubair, E-mail: mhd.zubair1@gmail.com; Khare, Neeraj [Department of Physics, Indian Institute of Technology Delhi, New Delhi (India)

2016-05-06

Single phase Cu{sub 2}ZnSnS{sub 4} (CZTS) nanoparticles have been synthesized by the microwave-assisted solution method in a one step process. Structural, morphological and optical characterizations of the CZTS nanoparticles have been carried out. X-ray diffraction confirms the single phase formation of CZTS nanoparticles with kesterite structure. SEM confirms the homogenous distribution of CZTS nanoparticles flower like assemblies. High resolution TEM image confirms the good crystallinity of the CZTS nanoparticles with the average grain size ~20 nm. The CZTS nanoparticles have strong optical absorption in the visible region with direct band gap as ~1.6 eV which is optimal for photovoltaic application.

Highly crystalline carbon dots from fresh tomato: UV emission and quantum confinement

Science.gov (United States)

Liu, Weijian; Li, Chun; Sun, Xiaobo; Pan, Wei; Yu, Guifeng; Wang, Jinping

2017-12-01

In this article, fresh tomatoes are explored as a low-cost source to prepare high-performance carbon dots by using microwave-assisted pyrolysis. Given that amino groups might act as nucleophiles for cleaving covalent bridging ester or ether in the crosslinked macromolecules in the biomass bulk, ethylenediamine (EDA) and urea with amino groups were applied as nucleophiles to modulate the chemical composites of the carbon nanoparticles in order to tune their fluorescence emission and enhance their quantum yields. Very interestingly, the carbon dots synthesized in the presence of urea had a highly crystalline nature, a low-degree amorphous surface and were smaller than 5 nm. Moreover, the doped N contributed to the formation of a cyclic form of core that resulted in a strong electron-withdrawing ability within the conjugated C plane. Therefore, this type of carbon dot exhibited marked quantum confinement, with the maximum fluorescence peak located in the UV region. Carbon nanoparticles greater than 20 nm in size, prepared using pristine fresh tomato and in the presence of EDA, emitted surface state controlled fluorescence. Additionally, carbon nanoparticles synthesized using fresh tomato pulp in the presence of EDA and urea were explored for bioimaging of plant pathogenic fungi and the detection of vanillin.

Microstructural and Z-scan measurement of silver nanoparticles

International Nuclear Information System (INIS)

Sivakami, R.; Dhanuskodi, S.

2015-01-01

Graphical abstract: - Highlights: • Novel Ag nanoparticles were prepared by hydrothermal method. • The modified forms of W-H analysis of Ag nanoparticles are reported first time. • Nonlinear optical (NLO) properties of Ag nanoflowers are reported and high nonlinearity was obtained. - Abstract: Silver nanoflowers were synthesized by the hydrothermal route. Formation of Ag nanoparticles is confirmed from the UV–vis spectrum where the surface plasmon absorption maxima are observed at 415–454 nm. FE-SEM and TEM images revealed the formation of silver nanoflowers and the flower-like silver nanostructures are estimated using transmission electron microscopy. XRD confirms that the synthesized silver is highly crystalline with face centered cubic structure. The X-ray line broadening is studied by the modified forms of Williamson–Hall analysis. The Z-scan results reveal that the flower-like silver nanostructures exhibit the nonlinear susceptilibility as 1.14 × 10 −5 esu

Evaluation of staphylococcus aureus growth in unirradiated and irradiated cured meats using the Gompertz equation

International Nuclear Information System (INIS)

Szczawinski, J.; Szczawinska, M.

1993-01-01

1. Sodium nitrite, in concentration of 156 mg/kg, exerted little (from practical point of view) inhibitory effect on S. aureus in cured meat. Its addition caused lag time extension, increase of exponential growth rate, decrease of generation time and maximum population density of staphylococci in samples of cured meat stored at 20 C. 2. Growth curves of Staphylococcus aureus in unirradiated and irradiated (50 kGy) meats cured without sodium nitrite were similar. 3. Irradiation of meat cured with 156 mg/kg sodium nitrite with increasing doses of ionizing radiation (0, 10, 30, 50 kGy) progressively decreased growth rates and lag time and increased generation time and maximum population densities of Staphylococcus aureus in samples inoculated after radiation treatment and incubated at 20 C. (orig.)

A low cost microwave synthesis method for preparation of gold nanoparticles

International Nuclear Information System (INIS)

Ngo Vo Ke Thanh; Lam Quang Vinh; Nguyen Dang Giang; Huynh Thanh Dat

2014-01-01

The gold nanoparticles (GNPs) in 15-20 nm size range have attention for fabrication of smart sensing devices in biomedical sciences as diagnostic tools. Citrate capped GNPs are negatively charged, which can be exploited for electrostatic interactions with some positively charged biomolecules like antibody. In this study, we are developing a low-cost technique by using a common microwave system with medium power for synthesizing gold nanoparticles with using sodium citrate (Na 3 Ct) reduction in chloroauric acid (HAuCl 4 .3H 2 O). It was found that the comparing with normal thermal method, the reaction by the microwave irradiation was much faster. Besides, the effects the sodium citrate concentration and optical properties of gold nanoparticles were studied. The optical properties of gold nanoparticles suspension were characterized by using transmission electron microscopy (TEM), X-ray diffraction (XRD), and UV-Vis absorption spectroscopy (UV-Vis). Maximum absorbance wavelengths (λ max ) for gold nanoparticles are ∼ 518-524 nm with the size of 12-25 nm. The size of gold nanoparticles decreases with increasing concentration of sodium citrate. Besides, the morphology of gold nanoparticles have a spherical shape with face-centered-cubic (fcc) crystalline structure. (author)

Biosynthesis, structural characterization and antimicrobial activity of gold and silver nanoparticles.

Science.gov (United States)

Ahmad, Tokeer; Wani, Irshad A; Manzoor, Nikhat; Ahmed, Jahangeer; Asiri, Abdullah M

2013-07-01

An eco friendly simple biosynthetic route was used for the preparation of monodisperse and highly crystalline gold and silver nanoparticles using cell free extract of fungus, Candida albicans. Transmission electron microscopic studies show the formation of gold and silver nanocrystals of average size of 5 nm and 30 nm with the specific surface areas of 18.9 m(2)/g and 184.4 m(2)/g respectively. The interaction of gold and silver nanoparticles with proteins has been formulated by FT-IR spectroscopy and thermal gravimetric analysis. The formation of gold and silver nanoparticles was also confirmed by the appearance of a surface plasmon band at 540 nm and 450 nm respectively. The antimicrobial activity of the synthesized gold and silver nanoparticles was investigated against both Staphylococcus aureus and Escherichia coli. The results suggest that these nanoparticles can be used as effective growth inhibitors against the test microorganisms. Greater bactericidal activity was observed for silver nanoparticles. The E. coli, a gram negative bacterium was found to be more susceptible to gold and silver nanoparticles than the S. aureus, a gram positive bacterium. Copyright © 2013 Elsevier B.V. All rights reserved.

Stabilizing ability of surfactant on physicochemical properties of drug nanoparticles generated from solid dispersions.

Science.gov (United States)

Thongnopkoon, Thanu; Puttipipatkhachorn, Satit

2017-07-01

This study was aimed to examine the nanoparticle formation from redispersion of binary and ternary solid dispersions. Binary systems are composed of various ratios of glibenclamide (GBM) and polyvinylpyrrolidone K30 (PVP-K30), whereas a constant amount at 2.5%w/w of a surfactant, sodium lauryl sulfate (SLS) or Gelucire44/14 (GLC), was added to create ternary systems. GBM nanoparticles were collected after the systems were dispersed in water for 15 min. The obtained nanoparticles were characterized for size distribution, crystallinity, thermal behavior, molecular structure, and dissolution properties. The results indicated that GBM nanoparticles could be formed when the drug content of the systems was lower than 30%w/w in binary systems and ternary systems containing SLS. The particle size ranged from 200 to 500 nm in diameter with narrow size distribution. The particle size was increased with increasing drug content in the systems. The obtained nanoparticles were spherical and showed the amorphous state. Furthermore, because of being amorphous form and reduced particle size, the dissolution of the generated nanoparticles was markedly improved compared with the GBM powder. In contrast, all the ternary solid dispersions prepared with GLC anomalously provided the crystalline particles with the size ranging over 5 µm and irregular shape. Interestingly, this was irrelevant to the drug content in the systems. These results indicated the ability of GLC to destabilize the polymer network surrounding the particles during particle precipitation. Therefore, this study suggested that drug content, quantity, and type of surfactant incorporated in solid dispersions drastically affected the physicochemical properties of the precipitated particles.

Green Synthesis, Characterization and Application of Proanthocyanidins-Functionalized Gold Nanoparticles

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Linhai Biao

2018-01-01

Full Text Available Green synthesis of gold nanoparticles using plant extracts is one of the more promising approaches for obtaining environmentally friendly nanomaterials for biological applications and environmental remediation. In this study, proanthocyanidins-functionalized gold nanoparticles were synthesized via a hydrothermal method. The obtained gold nanoparticles were characterized by ultraviolet and visible spectrophotometry (UV-Vis, Fourier transform infrared spectroscopy (FTIR, transmission electron microscopy (TEM and X-ray diffraction (XRD measurements. UV-Vis and FTIR results indicated that the obtained products were mainly spherical in shape, and that the phenolic hydroxyl of proanthocyanidins had strong interactions with the gold surface. TEM and XRD determination revealed that the synthesized gold nanoparticles had a highly crystalline structure and good monodispersity. The application of proanthocyanidins-functionalized gold nanoparticles for the removal of dyes and heavy metal ions Ni2+, Cu2+, Cd2+ and Pb2+ in an aqueous solution was investigated. The primary results indicate that proanthocyanidins-functionalized gold nanoparticles had high removal rates for the heavy metal ions and dye, which implies that they have potential applications as a new kind of adsorbent for the removal of contaminants in aqueous solution.

Green biosynthesis of silver nanoparticles using Curcuma longa tuber powder

Science.gov (United States)

Shameli, Kamyar; Ahmad, Mansor Bin; Zamanian, Ali; Sangpour, Parvanh; Shabanzadeh, Parvaneh; Abdollahi, Yadollah; Zargar, Mohsen

2012-01-01

Green synthesis of noble metal nanoparticles is a vastly developing area of research. Metallic nanoparticles have received great attention from chemists, physicists, biologists, and engineers who wish to use them for the development of a new-generation of nanodevices. In this study, silver nanoparticles were biosynthesized from aqueous silver nitrate through a simple and eco-friendly route using Curcuma longa tuber-powder extracts, which acted as a reductant and stabilizer simultaneously. Characterizations of nanoparticles were done using different methods, which included ultraviolet-visible spectroscopy, powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy-dispersive X-ray fluorescence spectrometry, and Fourier-transform infrared spectroscopy. The ultraviolet-visible spectrum of the aqueous medium containing silver nanoparticles showed an absorption peak at around 415 nm. Transmission electron microscopy showed that mean diameter and standard deviation for the formation of silver nanoparticles was 6.30 ± 2.64 nm. Powder X-ray diffraction showed that the particles are crystalline in nature, with a face-centered cubic structure. The most needed outcome of this work will be the development of value-added products from C. longa for biomedical and nanotechnology-based industries. PMID:23341739

Bakery products from irradiated and unirradiated eggs - detection of irradiation in a processed food

International Nuclear Information System (INIS)

Pfordt, J.; Grabowski, H.U. von

1995-01-01

The detection of radiation-specific degradation products in fat has become an established method which has successfully been applied to egg products. This study is making evident the detectability of irradiated eggs as an ingredient of specified processed foods. Tart layers were produced from both irradiated and non-irradiated liquid whole egg. When the fat components were isolated from the tart layers and investigated by GC/MS, the presence of irradiated eggs could clearly be shown. While the radiation-induced hydrocarbons and 2-alkylcyclobutanones could not be found in unirradiated samples, tart layers from irradiated eggs contained these substances. Especially for the hydrocarbons a satisfying correlation between radiation dose and concentration could be observed. The concentrations of radiation-induced compounds were generally lower in the tart layers than in the liquid egg samples they had been produced from. (orig.) [de

Synthesis of cobalt boride nanoparticles using radio frequency thermal plasma

International Nuclear Information System (INIS)

Lapitan, Jr. Lorico DS.; Ying Ying Chen; Seesoek Choe; Watanabe, Takayuki

2012-01-01

Nano size cobalt boride particles were synthesized from vapor phase using a 30 kw-4 MHz radio frequency (RF) thermal plasma. Cobalt and boron powder mixtures used as precursors in different composition and feed rate were evaporated immediately in the high temperature plasma and cobalt boride nanoparticles were produced through the quenching process. The x-ray diffractometry (XRD) patterns of cobalt boride nanoparticles prepared from the feed powder ratio of 1:2 and 1:3 for Co: B showed peaks that are associated with the Co 2 B and CoB crystal phases of cobalt boride. The XRD analysis revealed that increasing the powder feed rate results in a higher mass fraction and a larger crystalline diameter of cobalt boride nanoparticles. The images obtained by field emission scanning electron microscopy (FE-SEM) revealed that cobalt boride nanoparticles have a spherical morphology. The crystallite size of the particles estimated with XRD was found to be 18-22 nm. (author)

Nitrophenol chemi-sensor and active solar photocatalyst based on spinel hetaerolite nanoparticles.

Science.gov (United States)

Khan, Sher Bahadar; Rahman, Mohammed M; Akhtar, Kalsoom; Asiri, Abdullah M; Rub, Malik Abdul

2014-01-01

In this contribution, a significant catalyst based on spinel ZnMn2O4 composite nanoparticles has been developed for electro-catalysis of nitrophenol and photo-catalysis of brilliant cresyl blue. ZnMn2O4 composite (hetaerolite) nanoparticles were prepared by easy low temperature hydrothermal procedure and structurally characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) and UV-visible spectroscopy which illustrate that the prepared material is optical active and composed of well crystalline body-centered tetragonal nanoparticles with average size of ∼ 38 ± 10 nm. Hetaerolite nanoparticles were applied for the advancement of a nitrophenol sensor which exhibited high sensitivity (1.500 µAcm(-2) mM(-1)), stability, repeatability and lower limit of detection (20.0 µM) in short response time (10 sec). Moreover, hetaerolite nanoparticles executed high solar photo-catalytic degradation when applied to brilliant cresyl blue under visible light.

Synthesis and structural, optical and thermal properties of CdS:Zn2+ nanoparticles

Science.gov (United States)

Muruganandam, S.; Anbalagan, G.; Murugadoss, G.

2014-12-01

Undoped and Zn (1-5, 10 %) -doped CdS nanoparticles were successfully synthesized by chemical method and polyvinylpyrrolidone was used as capping agent. The morphology and crystalline structure of the samples were studied by transmission electron microscopy and X-ray diffraction. The average particle size of the spherical nanoparticles determined by these techniques was of the order of 2.5-6 nm. The functional groups of the capping agent on CdS:Zn2+ surface were identified by FT-IR study. The band gap of the nanoparticles was calculated using UV-visible absorption spectra and the result showed that the band gap values were dramatically blue shifted from the bulk CdS. The optimum concentration of the doping ions was selected through absorption study. Photoluminescence of the CdS:Zn2+ nanoparticle showed strong blue and green emission. The thermal properties of the nanoparticles were analyzed by thermogravimetric-differential thermal analysis.

Paramagnetic Nanocrystals: Remarkable Lanthanide-Doped Nanoparticles with Varied Shape, Size, and Composition.

Science.gov (United States)

Holmberg, Rebecca J; Aharen, Tomoko; Murugesu, Muralee

2012-12-20

Magnetic nanoparticles have been developed in recent years with applications in unique and crucial areas such as biomedicine, data storage, environmental remediation, catalysis, and so forth. NaYF4 nanoparticles were synthesized and isolated with lanthanide dopant percentages, confirmed by ICP-OES measurements, of Er, Yb, Tb, Gd, and Dy that were in agreement with the targeted ratios. SEM images showed a distinct variation in particle size and shape with dopant type and percentage. HRTEM and XRD studies confirmed the particles to be crystalline, possessing both α and β phases. Magnetic measurements determined that all of the nanoparticles were paramagnetic and did not exhibit a blocking temperature from 2 to 300 K. The multifunctional properties of these nanoparticles make them suitable for many applications, such as multimodal imaging probes, up-conversion fluorescent markers, as well as MRI contrast agents.

Solar-assisted synthesis of ZnO nanoparticles using lime juice: a green approach

Science.gov (United States)

Hinge, Shruti P.; Pandit, Aniruddha B.

2017-12-01

Zinc oxide (ZnO) nanoparticles are those nanoparticles which have been synthesized in various morphologies and shapes. Their size and shape dependent properties and their applications in vivid sectors of science and technology make them interesting to synthesize. Present work reports a green method for ZnO nanoparticle synthesis using lime juice and sunlight. ZnO nanoparticles were also synthesized by conventionally used methods like heating, stirring or no heating and/or stirring. The nanoparticles were characterized using different techniques like UV-vis spectroscopy, scanning electron microscopy (SEM), x-ray diffraction (XRD) and dynamic light scattering (DLS). Thermo gravimetric analysis (TGA) was also carried out for the intermediate product to select the calcination temperature. Stoichiometric study reveals that the intermediate product formed is zinc citrate dihydrate. The synthesized calcined nanoparticles have good crystallinity, uniform shape, and high purity and were in the size range of 20-30 nm. These nanoparticles formed agglomerates of various shapes in the size range of 200-750 nm. This process is ecofriendly and is amiable for easy scale up.

Trimethylamine Sensors Based on Au-Modified Hierarchical Porous Single-Crystalline ZnO Nanosheets

Directory of Open Access Journals (Sweden)

Fanli Meng

2017-06-01

Full Text Available It is of great significance for dynamic monitoring of foods in storage or during the transportation process through on-line detecting trimethylamine (TMA. Here, TMA were sensitively detected by Au-modified hierarchical porous single-crystalline ZnO nanosheets (HPSCZNs-based sensors. The HPSCZNs were synthesized through a one-pot wet-chemical method followed by an annealing treatment. Polyethyleneimine (PEI was used to modify the surface of the HPSCZNs, and then the PEI-modified samples were mixed with Au nanoparticles (NPs sol solution. Electrostatic interactions drive Au nanoparticles loading onto the surface of the HPSCZNs. The Au-modified HPSCZNs were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, transmission electron microscopy (TEM and energy dispersive spectrum (EDS, respectively. The results show that Au-modified HPSCZNs-based sensors exhibit a high response to TMA. The linear range is from 10 to 300 ppb; while the detection limit is 10 ppb, which is the lowest value to our knowledge.

Trimethylamine Sensors Based on Au-Modified Hierarchical Porous Single-Crystalline ZnO Nanosheets.

Science.gov (United States)

Meng, Fanli; Zheng, Hanxiong; Sun, Yufeng; Li, Minqiang; Liu, Jinhuai

2017-06-22

It is of great significance for dynamic monitoring of foods in storage or during the transportation process through on-line detecting trimethylamine (TMA). Here, TMA were sensitively detected by Au-modified hierarchical porous single-crystalline ZnO nanosheets (HPSCZNs)-based sensors. The HPSCZNs were synthesized through a one-pot wet-chemical method followed by an annealing treatment. Polyethyleneimine (PEI) was used to modify the surface of the HPSCZNs, and then the PEI-modified samples were mixed with Au nanoparticles (NPs) sol solution. Electrostatic interactions drive Au nanoparticles loading onto the surface of the HPSCZNs. The Au-modified HPSCZNs were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive spectrum (EDS), respectively. The results show that Au-modified HPSCZNs-based sensors exhibit a high response to TMA. The linear range is from 10 to 300 ppb; while the detection limit is 10 ppb, which is the lowest value to our knowledge.

Method of Creating Micro-scale Silver Telluride Grains Covered with Bismuth Nanoparticles

Science.gov (United States)

Kim, Hyun-Jung (Inventor); Choi, Sang Hyouk (Inventor); King, Glen C. (Inventor); Park, Yeonjoon (Inventor); Lee, Kunik (Inventor)

2014-01-01

Provided is a method of enhancing thermoelectric performance by surrounding crystalline semiconductors with nanoparticles by contacting a bismuth telluride material with a silver salt under a substantially inert atmosphere and a temperature approximately near the silver salt decomposition temperature; and recovering a metallic bismuth decorated material comprising silver telluride crystal grains.

Fabrication of drug nanoparticles by evaporative precipitation of nanosuspension.

Science.gov (United States)

Kakran, M; Sahoo, N G; Li, L; Judeh, Z; Wang, Y; Chong, K; Loh, L

2010-01-04

Evaporative precipitation of nanosuspension (EPN) was used to fabricate nanoparticles of a poorly water-soluble antimalarial drug, artemisinin (ART), with the aim of enhancing its dissolution rate. We investigated the nanoparticle fabrication of ART via a full factorial experimental design considering the effects of drug concentration and solvent to antisolvent ratio on the physical, morphological and dissolution properties of ART. Characterization of the original ART powder and EPN prepared ART nanoparticles was carried out by scanning electron microscopy, differential scanning calorimetry (DSC), X-ray diffraction (XRD) and dissolution tester. DSC and XRD studies suggested that the crystallinity of EPN prepared ART nanoparticles decreased with increasing drug concentration and ratio of solvent to antisolvent. The particle diameters of EPN prepared ART nanoparticles were found to be 100-360 nm. The dissolution of EPN prepared ART nanoparticles markedly increased as compared to the original ART powder. A percent dissolution surface-response model was used to elucidate the significant and direct relationships between drug concentration and solvent to antisolvent ratio on one hand and percent dissolution on the other hand. The best dissolution percent was found to be 75.9%, at the drug concentration of 15 mg/mL and solvent to antisolvent ratio (by volume) of 1:20.

Green Synthesis and Antibacterial Effect of Silver Nanoparticles Using Vitex Negundo L.

Directory of Open Access Journals (Sweden)

Fatima Abu Bakar

2011-08-01

Full Text Available Different biological methods are gaining recognition for the production of silver nanoparticles (Ag-NPs due to their multiple applications. One of the most important applications of Ag-NPs is their use as an anti-bacterial agent. The use of plants in the synthesis of nanoparticles emerges as a cost effective and eco-friendly approach. In this study the biosynthesis of silver nanoparticles using Vitex negundo L. extract and its antimicrobial properties has been reported. The resulting silver particles are characterized using transmission electron microscopy (TEM, X-ray diffraction (XRD and UV–Visible (UV-Vis spectroscopic techniques. The TEM study showed the formation of silver nanoparticles in the 10–30 nm range and average 18.2 nm in size. The XRD study showed that the particles are crystalline in nature, with a face centered cubic (fcc structure. The silver nanoparticles showed the antimicrobial activity against Gram positive and Gram negative bacteria. Vitex negundo L. was found to display strong potential for the synthesis of silver nanoparticles as antimicrobial agents by rapid reduction of silver ions (Ag+ to Ag0.

Studies on magnetic properties of chemically synthesized crystalline calcium ferrite nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Debnath, A., E-mail: debnathanimesh@gmail.com [Department of Civil Engineering, National Institute of Technology Agartala, Jirania, West Tripura, 799046 India (India); Bera, A.; Saha, B. [Department of Physics, National Institute of Technology Agartala, Jirania, West Tripura 799046 (India); Chattopadhyay, K. K. [Department of Physics, Jadavpur University, Kolkata 700 032 (India)

2016-05-23

Spinel-type ferrites have taken a very important role for modern electronic industry. Most of these ferrites exhibit low-loss dielectric properties, high resistivity, low eddy current and also high temperature ferromagnetism. Calcium ferrite is one such important metal oxide which is environmentally safe, chemically stable, low cost and greatly abundant. This outstanding material of calcium ferrite is synthesized by a simple chemical precipitation method using NaOH as the precipitating agent. Ferric chloride anhydrous (FeCl{sub 3}) and Calcium chloride dihydrate (CaCl{sub 2}.2H{sub 2}O) were used as iron and calcium sources respectively. The samples were heated at 200°C for 8h to obtain homogeneous powder of Calcium ferrite. The powders were characterized by using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), Transmission electrical microscopy (TEM), and Fourier transform infrared spectroscopic (FTIR) measurements. The polycrystalline nature of the sample was confirmed by X-ray diffraction study. The magnetic properties of the sample were investigated by vibrating sample magnetometer (VSM) measurements. Magnetization curve of the prepared sample depicts that as synthesized calcium ferrite nanoparticles have saturation magnetic moment of 1.74 emu/g and the coercivity of 35.08 Oe with superparamagnetic behavior. The synthesized calcium ferrite nanoparticles with such magnetic properties will be a candidate material for different applications in electronics and exploring its functionality in the field of recently developing semiconductor device physics and spintronics.

Studies on magnetic properties of chemically synthesized crystalline calcium ferrite nanoparticles

International Nuclear Information System (INIS)

Debnath, A.; Bera, A.; Saha, B.; Chattopadhyay, K. K.

2016-01-01

Spinel-type ferrites have taken a very important role for modern electronic industry. Most of these ferrites exhibit low-loss dielectric properties, high resistivity, low eddy current and also high temperature ferromagnetism. Calcium ferrite is one such important metal oxide which is environmentally safe, chemically stable, low cost and greatly abundant. This outstanding material of calcium ferrite is synthesized by a simple chemical precipitation method using NaOH as the precipitating agent. Ferric chloride anhydrous (FeCl_3) and Calcium chloride dihydrate (CaCl_2.2H_2O) were used as iron and calcium sources respectively. The samples were heated at 200°C for 8h to obtain homogeneous powder of Calcium ferrite. The powders were characterized by using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), Transmission electrical microscopy (TEM), and Fourier transform infrared spectroscopic (FTIR) measurements. The polycrystalline nature of the sample was confirmed by X-ray diffraction study. The magnetic properties of the sample were investigated by vibrating sample magnetometer (VSM) measurements. Magnetization curve of the prepared sample depicts that as synthesized calcium ferrite nanoparticles have saturation magnetic moment of 1.74 emu/g and the coercivity of 35.08 Oe with superparamagnetic behavior. The synthesized calcium ferrite nanoparticles with such magnetic properties will be a candidate material for different applications in electronics and exploring its functionality in the field of recently developing semiconductor device physics and spintronics.

STUDY OF SUBCELLULAR DISTRIBUTION OF CRYSTALLINE MESO-TETRA(3-PYRIDYLBACTERIOCHLORIN NANOPARTICLES

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Yu. S. Maklygina

2016-01-01

Full Text Available The results of the study of subcellular distribution of molecular meso-tetra(3-pyridylbacteriochlorin nanocrystals proposed as therapeutic agents for photodynamic therapy are represented in the article. Investigations and measurement of spectroscopic properties of molecular crystals of near-infrared photosensitizer were conducted using special device complex based on fiber-optic spectrometer. Investigation and analysis of the pattern of subcellular accumulation of meso-tetra(3-pyridylbacteriochlorin in molecular (dimethyl sulfoxide (DMSO as solvent and nanocrystalline forms on different cell lines: human monocytes (THP-1, human cervical cancer cells (HeLa and mouse malignant brain tumor cells (glioma C6. The dynamics of subcellylar accumulation of the agent at concentration of 5 and 10 mg/l was assessed with laser microscope-spectrum analyzer and by confocal microscopy. The study showed that in the course of interaction with cell lines molecular nanocrystals of the agent developed ability to fluorescence. Hence, in the cellular environment meso-tetra(3-pyridyl bacteriochlorin nanoparticles became phototoxic giving opportunities for their use for fluorescence diagnosis and photodynamic therapy. Specific role of meso-tetra(3-pyridylbacteriochlorin in the range of photosensitizers is determined by its spectral characteristics, i.e. absorption and fluorescence in near-infrared band, which allows measuring and affecting on deeper layers of biotissue. Thus, the use of meso-tetra(3-pyridylbacteriochlorin nanoparticles as nanophotosensitizers may improve the efficacy of diagnosis and treatment of deep-seated tumors.

Biosynthesis, characterization and antimicrobial action of silver nanoparticles from root bark extract of Berberislycium Royle.

Science.gov (United States)

Mehmood, Ansar; Murtaza, Ghulam; Bhatti, Tariq Mahmood; Kausar, Rehana; Ahmed, Muhammad Jamil

2016-01-01

Various biological methods are being recognized for the fabrication of silver nanoparticles, which are used in several fields. The phytosynthesis of nanoparticles came out as a cost effective and enviro-friendly approach. When root bark extract of Berberis lycium was treated with silver ions, they reduced to silver nanoparticles, which were spherical, crystalline, size ranged from 10-100nm and capped by biomolecules. Synthesized silver nanoparticles were characterized by UV-visible spectroscopy, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD) and Fourier Transform Infra Red Spectroscopy (FTIR). The plant mediated synthesized silver nanoparticles showed pronounced antimicrobial activities against both Gram negative bacteria (Escherichia coli, Klebseilla pneumoniae, Pseudomonas aeruginosa) and Gram positive bacteria (Staphylococcus aureus and Bacillus subtilis). The plant mediated process proved to be non-toxic and low cost contender as reducing agent for synthesizing stable silver nanoparticles.

Resistive switching behavior of SiOx layers with Si nanoparticles

International Nuclear Information System (INIS)

Nesheva, D; Pantchev, B; Manolov, E; Dzhurkov, V; Nedev, N; Valdez, B; Nedev, R

2017-01-01

First results on resistive switching in SiO x film containing crystalline silicon nanoparticles are reported. SiO x layers ( x = 1.15) with thickness of 50 nm were deposited on n-Si crystalline substrates and annealed for 60 min at 1000 o C to grow crystalline nanoparticles. Part of the samples were annealed in an inert atmosphere, while the rest were subjected to a two-step (O 2 +N 2 /N 2 ) annealing process. Current-voltage (I-V) characteristics were by applying positive or negative voltage to the top contact. For both types of samples the I-V characteristics were asymmetric with lower currents measured at negative voltage, especially in the case of two-step annealed samples. In most of the N 2 annealed structures switching behavior high-low/low-high resistance state was observed in both polarities at voltages with amplitudes in the range (2 - 4) V. Uncontrolled switching low/high resistance was also seen, more frequently at positive voltages. In contrast, the two-step annealed samples showed stable behavior. The transition high-low resistance state was achieved by negative voltages in the (-2, -5) V range leading to an increase of the current by more than three orders of magnitude. The structures were reset to the high resistive state, by positive voltage in the range (3 - 4) V. Uncontrolled switching was not observed in the two-step annealed samples for both polarities and they showed higher reliability regarding the number of switching cycles. (paper)

Preparation of nickel and Ni_3Sn nanoparticles via extension of conventional citric acid and ethylene diamine tetraacetic acid mediated sol–gel method

International Nuclear Information System (INIS)

Li, Pingyun; Deng, Guodong; Guo, Xiaode; Liu, Hongying; Jiang, Wei; Li, Fengsheng

2016-01-01

This work aims to extend the application field of sol–gel process from conventional oxides, carbides, sulfides to metallic nanocrystalline materials. Metallic ions were coordinated with chelating agents of citric acid (CA) and ethylene diamine tetraacetic acid (EDTA) in aqueous solution. Then the solutions were dried at 383 K, resulting in the formation of sol and gel. Heating treatments of dried gels were then carried out with protection of N_2 atmosphere. Ni and Ni_3Sn alloy nanoparticles were obtained by this sol–gel method in the range of 623–823 K. The as-prepared Ni and Ni_3Sn alloy nanoparticles have average grain sizes of 15 and 30 nm, and have face-centred-cubic (fcc) crystalline phase. Our results provide new insight into the application of conventional sol–gel method. - Graphical abstract: Sol–gel method is conventionally applied to prepare oxides, carbides, and sulfides. In this work, the application field of sol–gel method is extended to metallic nanoparticles. By using citric acid (CA) and ethylene diamine tetraacetic acid (EDTA) mediated sol–gel method, metallic Ni (a and c) and Ni_3Sn (b and d) alloy nanoparticles can be prepared when the heating treatments are performed under N_2 protecting atmosphere. The Ni and Ni_3Sn nanoparticles have face-centered-cubic (fcc) crystalline phase and ultrafine grain sizes. Diffraction peaks of (110) superstructure reflection plane of Ni_3Sn nanoparticles can also be observed in Figure b, which can be considered as direct evidence of formation of alloy crystalline phase by performing this sol–gel method. - Highlights: • Ni and Ni_3Sn alloy nanoparticles have been prepared by sol–gel processes. • Citric acid and ethylene diamine tetraacetic acid were applied as chelating agent. • Diffraction peak of superstructure reflection plane of Ni_3Sn was detected by XRD. • A novel strategy for preparation of alloy nanoparticles has been presented.

Synthesis of water soluble glycine capped silver nanoparticles and their surface selective interaction

International Nuclear Information System (INIS)

Agasti, Nityananda; Singh, Vinay K.; Kaushik, N.K.

2015-01-01

Highlights: • Synthesis of water soluble silver nanoparticles at ambient reaction conditions. • Glycine as stabilizing agent for silver nanoparticles. • Surface selective interaction of glycine with silver nanoparticles. • Glycine concentration influences crystalinity and optical property of silver nanoparticles. - Abstract: Synthesis of biocompatible metal nanoparticles has been an area of significant interest because of their wide range of applications. In the present study, we have successfully synthesized water soluble silver nanoparticles assisted by small amino acid glycine. The method is primarily based on reduction of AgNO 3 with NaBH 4 in aqueous solution under atmospheric air in the presence of glycine. UV–vis spectroscopy, transmission electron microscopy (TEM), X–ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, thermogravimetry (TG) and differential thermal analysis (DTA) techniques used for characterization of resulting silver nanoparticles demonstrated that, glycine is an effective capping agent to stabilize silver nanoparticles. Surface selective interaction of glycine on (1 1 1) face of silver nanoparticles has been investigated. The optical property and crystalline behavior of silver nanoparticles were found to be sensitive to concentration of glycine. X–ray diffraction studies ascertained the phase specific interaction of glycine on silver nanoparticles. Silver nanoparticles synthesized were of diameter 60 nm. We thus demonstrated an efficient synthetic method for synthesis of water soluble silver nanoparticles capped by amino acid under mild reaction conditions with excellent reproducibility

Green synthesis of NiO nanoparticles using Moringa oleifera extract and their biomedical applications: Cytotoxicity effect of nanoparticles against HT-29 cancer cells.

Science.gov (United States)

Ezhilarasi, A Angel; Vijaya, J Judith; Kaviyarasu, K; Maaza, M; Ayeshamariam, A; Kennedy, L John

2016-11-01

Green protocols for the synthesis of nickel oxide nanoparticles using Moringa oleifera plant extract has been reported in the present study as they are cost effective and ecofriendly, moreover this paper records that the nickel oxide (NiO) nanoparticles prepared from green method shows better cytotoxicity and antibacterial activity. The NiO nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), High resolution transmission electron microscopy (HRTEM), Energy dispersive X-ray analysis (EDX), and Photoluminescence spectroscopy (PL). The formation of a pure nickel oxide phase was confirmed by XRD and FTIR. The synthesized NiO nanoparticles was single crystalline having face centered cubic phase and has two intense photoluminescence emissions at 305.46nm and 410nm. The formation of nano- and micro-structures was confirmed by HRTEM. The in-vitro cytotoxicity and cell viability of human cancer cell HT-29 (Colon Carcinoma cell lines) and antibacterial studies against various bacterial strains were studied with various concentrations of nickel oxide nanoparticles prepared from Moringa oleifera plant extract. MTT assay measurements on cell viability and morphological studies proved that the synthesized NiO nanoparticles posses cytotoxic activity against human cancer cells and the various zones of inhibition (mm), obtained revealed the effective antibacterial activity of NiO nanoparticles against various Gram positive and Gram negative bacterial pathogens. Copyright © 2016 Elsevier B.V. All rights reserved.

Effect of helium pressure on the response of unirradiated UO2 subjected to thermal transients

International Nuclear Information System (INIS)

Fenske, G.R.; Chapello, P.M.; Emerson, J.E.; Poeppel, R.B.

1983-01-01

The effect of helium pressure on the transient response of unirradiated depleted UO 2 subjected to simulated hypothetical loss-of-flow accidents in a gas-cooled fast reactor was examined by use of the direct electrical heating technique. Transient tests were performed at pressures ranging from 7 to 10 X 10 5 Pa(7 to 10 atm) to 7 to 8 MPa (70 to 80 atm) on radially restrained and unrestrained fuel segments. The average heating rates ranged from about17 to 240 J/g x s. The results indicate that while the mechanical integrity of the fuel segment was independent of the test pressure, the rapid ejection of molten fuel from pellet interfaces of unrestrained fuel, observed at the lower pressures, was delayed or suppressed at the higher pressures

Carboxylic acid effects on the size and catalytic activity of magnetite nanoparticles.

Science.gov (United States)

Hosseini-Monfared, Hassan; Parchegani, Fatemeh; Alavi, Sohaila

2015-01-01

Magnetite nanoparticles (Fe3O4-NPs) were successfully synthesized in diethylene glycol in the presence of carboxylic acids. They were characterized using XRD, SEM and FTIR. Carboxylic acid plays a critical role in determining the morphology, particle size and size distribution of the resulting particles. The results show that as-prepared magnetite nanoparticles are monodisperse and highly crystalline. The nanoparticles can be easily dispersed in aqueous media and other polar solvents due to coated by a layer of hydrophilic polyol and carboxylic acid ligands in situ. Easily prepared Fe3O4-NPs have been shown to be an active, recyclable, and highly selective catalyst for the epoxidation of cyclic olefins with aqueous 30% H2O2. Copyright © 2014 Elsevier Inc. All rights reserved.

XaNSoNS: GPU-accelerated simulator of diffraction patterns of nanoparticles

Directory of Open Access Journals (Sweden)

V.S. Neverov

2017-01-01

Full Text Available XaNSoNS is an open source software with GPU support, which simulates X-ray and neutron 1D (or 2D diffraction patterns and pair-distribution functions (PDF for amorphous or crystalline nanoparticles (up to ∼107 atoms of heterogeneous structural content. Among the multiple parameters of the structure the user may specify atomic displacements, site occupancies, molecular displacements and molecular rotations. The software uses general equations nonspecific to crystalline structures to calculate the scattering intensity. It supports four major standards of parallel computing: MPI, OpenMP, Nvidia CUDA and OpenCL, enabling it to run on various architectures, from CPU-based HPCs to consumer-level GPUs.

XaNSoNS: GPU-accelerated simulator of diffraction patterns of nanoparticles

Science.gov (United States)

Neverov, V. S.

XaNSoNS is an open source software with GPU support, which simulates X-ray and neutron 1D (or 2D) diffraction patterns and pair-distribution functions (PDF) for amorphous or crystalline nanoparticles (up to ∼107 atoms) of heterogeneous structural content. Among the multiple parameters of the structure the user may specify atomic displacements, site occupancies, molecular displacements and molecular rotations. The software uses general equations nonspecific to crystalline structures to calculate the scattering intensity. It supports four major standards of parallel computing: MPI, OpenMP, Nvidia CUDA and OpenCL, enabling it to run on various architectures, from CPU-based HPCs to consumer-level GPUs.

Crystalline color superconductivity

International Nuclear Information System (INIS)

Alford, Mark; Bowers, Jeffrey A.; Rajagopal, Krishna

2001-01-01

In any context in which color superconductivity arises in nature, it is likely to involve pairing between species of quarks with differing chemical potentials. For suitable values of the differences between chemical potentials, Cooper pairs with nonzero total momentum are favored, as was first realized by Larkin, Ovchinnikov, Fulde, and Ferrell (LOFF). Condensates of this sort spontaneously break translational and rotational invariance, leading to gaps which vary periodically in a crystalline pattern. Unlike the original LOFF state, these crystalline quark matter condensates include both spin-zero and spin-one Cooper pairs. We explore the range of parameters for which crystalline color superconductivity arises in the QCD phase diagram. If in some shell within the quark matter core of a neutron star (or within a strange quark star) the quark number densities are such that crystalline color superconductivity arises, rotational vortices may be pinned in this shell, making it a locus for glitch phenomena

Multifunctional EuYVO4 nanoparticles coated with mesoporous silica

International Nuclear Information System (INIS)

Justino, Larissa G.; Nigoghossian, Karina; Capote, Ticiana S.O.; Scarel-Caminaga, Raquel M.; Ribeiro, Sidney J.L.; Caiut, José Maurício A.

2016-01-01

Mesoporous structures are interesting materials for the incorporation of dyes, drugs, and luminescent systems, leading to materials with important multifunctionalities. In a very unique way, these guest/host materials combine the high stability of inorganic systems, new guest-structuring features, and adsorption mechanisms in their well-defined pores. This work evaluates the luminescent properties of rare earth-doped YVO 4 nanoparticles coated with a mesoporous silica shell. The use of two different synthesis methodologies allowed for particle size control. The crystalline phase emerged without further heat treatment. The mesoporous shell decreased undesirable quenching effects on YVO 4 :Eu 3+ nanoparticles and rendered them biocompatible. The materials prepared herein could have interesting applications as luminescent markers or drug release systems.

Preparation of transition metal sulfide nanoparticles via hydrothermal route

International Nuclear Information System (INIS)

Fei-Ling, P.; Chin-Hua, C.; Sarani Zakaria; Tze-Khong, L.; Mohd Ambar Yarmo; Nay-Ming, H.

2010-01-01

Nano sized copper sulfide, iron sulfide and molybdenum sulfide were successfully synthesised via a simple hydrothermal method. Sodium thiosulfate pentahydrate (Na 2 S 2 O 3 ·5H 2 O) and hydroxylamine sulfate ((H 3 NO) 2 ·H 2 SO 4 ) were used as the starting materials and reacted with the transition metal source at 200 degree Celsius for 90 min. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and Fourier transform infrared spectroscopy (FTIR). Spherical shape CuS and FeS 2 nanoparticles with high crystallinity were successfully produced. The transmission electron micrographs revealed the well-dispersibility of the produced nanoparticles. Scanning electron micrograph showed the MoS 2 nanoparticles possessed a spherical shape with sheet-like structure covering on the outer surface of the particles. (author)

Effect of cobalt doping on crystallinity, stability, magnetic and optical properties of magnetic iron oxide nano-particles

International Nuclear Information System (INIS)

Anjum, Safia; Tufail, Rabia; Rashid, Khalid; Zia, Rehana; Riaz, S.

2017-01-01

Highlights: • The stability of Co x Fe (2-x) O 3 nanoparticles enhances. • Energy losses increases. • Anisotropy of NP is high. - Abstract: This paper is dedicated to investigate the effect of Co 2+ ions in magnetite Fe 3 O 4 nano-particles with stoichiometric formula Co x Fe 3-x O 4 where (x = 0, 0.05, 0.1 and 0.15) prepared by co-precipitation method. The structural, thermal, morphological, magnetic and optical properties of magnetite and Co 2+ doped magnetite nanoparticles have been carried out using X-ray Diffractometer, Fourier Transform Infrared Spectroscopy, Themogravimetric Analysis, Scanning Electron Microscopy, Vibrating Sample Magnetometer (VSM) and UV–Vis Spectrometer (UV–Vis) respectively. Structural analysis verified the formation of single phase inverse spinel cubic structure with decrease in lattice parameters due to increase in cobalt content. FTIR analysis confirms the single phase of Co x Fe 3-x O 4 nanoparticles with the major band at 887 cm −1 , which might be due to the stretching vibrations of metal-oxide bond. The DSC results corroborate the finding of an increase in the maghemite to hematite phase transition temperature with increase in Co 2+ content. The decrease in enthalpy with increase in Co 2+ concentration attributed to the fact that the degree of conversion from maghemite to hematite decrease which shows that the stability increases with increasing Co 2+ content in B-site of Fe 3 O 4 structure. SEM analysis demonstrated the formation of spherical shaped nanoparticles with least agglomeration. The magnetic measurements enlighten that the coercivity and anisotropy of Co x Fe 3-x O 4 nanoparticles are significantly increased. From UV–Vis analysis it is revealed that band gap energy increases with decreasing particle size. This result has a great interest for magnetic fluid hyperthermia application (MPH).

Properties of unirradiated fuel element graphites H-451 and SO818. [Bulk density, tensile properties, thermal expansion, thermal conductivity

Energy Technology Data Exchange (ETDEWEB)

Engle, G.B.; Johnson, W.R.

1976-10-08

Nuclear graphites H-451, lot 440 (Great Lakes Carbon Corporation (GLCC)), and SO818 (Airco Speer Division, Air Reduction Corporation (AS)) are described, and physical, mechanical, and chemical property data are presented for the graphites in the unirradiated state. A summary of the mean values of the property data and of data on TS-1240 and H-451, lot 426, is tabulated. A direct comparison of H-451, lot 426, chosen for Fort St. Vrain (FSV) fuel reload production, TS-1240, and SO818 may be made from the table. (auth)

The effects of ZnO2 nanoparticles on properties of concrete using ground granulated blast furnace Slag as binder

Directory of Open Access Journals (Sweden)

Ali Nazari

2011-09-01

Full Text Available In the present study, flexural strength together with pore structure, thermal behavior and microstructure of concrete containing ground granulated blast furnace slag with different amount of ZnO2 nanoparticles has been investigated. Portland cement was replaced by different amounts of ground granulated blast furnace slag and the properties of concrete specimens were investigated. Although it negatively impact the properties of concrete, ground granulated blast furnace slag was found to improve the physical and mechanical properties of concrete up to 45 wt. (%. ZnO2 nanoparticles with the average particle size of 15 nm were added partially to concrete with the optimum content of 45 wt. (% of ground granulated blast furnace slag and physical and mechanical properties of the specimens was measured. ZnO2 nanoparticle as a partial replacement of cement up to 3 wt. (% could accelerate C-S-H gel formation as a result of increased crystalline Ca(OH2 amount at the early age of hydration and hence increase flexural strength of concrete. The increased the ZnO2 nanoparticles' content more than 3 wt. (%, causes the reduced the flexural strength because of the decreased crystalline Ca(OH2 content required for C-S-H gel formation together with unsuitable dispersion of nanoparticles in the concrete matrix. ZnO2 nanoparticles could improve the pore structure of concrete and shift the distributed pores to harmless and few-harm pores.

Synthesis of lanthanum tungstate interconnecting nanoparticles by high voltage electrospinning

Energy Technology Data Exchange (ETDEWEB)

Keereeta, Yanee, E-mail: ynkeereeta@gmail.com [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongtem, Titipun, E-mail: ttpthongtem@yahoo.com [Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongtem, Somchai [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

2015-10-01

Graphical abstract: - Highlights: • La{sub 2}(WO{sub 4}){sub 3} as one of semiconducting materials. • H.V. electrospinning was used to synthesize La{sub 2}(WO{sub 4}){sub 3} interconnecting nanoparticles. • A promising material for photoemission. - Abstract: Lanthanum tungstate (La{sub 2}(WO{sub 4}){sub 3}) interconnecting nanoparticles in the shape of fibers were successfully synthesized by electrospinning in combination with high temperature calcination. In this research, calcination temperature for the synthesis of the fibers evidently influenced the diameter, morphology and crystalline degree. The crystalline monoclinic La{sub 2}(WO{sub 4}){sub 3} fibers with 200–700 nm in diameter, two main Raman peaks at 945 and 927 cm{sup −1}, FTIR stretching modes at 936 and 847 cm{sup −1}, 2.02 eV energy gap and 415–430 nm blue emission were synthesized by calcination of inorganic/organic hybrid fibers at 750 °C for 5 h, characterized by X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, UV–visible spectroscopy and photoluminescence (PL) spectroscopy. The surface of the composite fibers before calcination was very smooth. Upon calcination the composite fibers at 750 °C for 5 h, they were transformed into nanoparticles join together in the shape of fibers with rough surface.

Effect of substrate interface on the magnetism of supported iron nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Balan, A. [Swiss Light Source, Paul Scherrer Institut (PSI), Villigen CH-5232 (Switzerland); Fraile Rodríguez, A. [Departament de Física Fonamental and Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, E-08028 Barcelona (Spain); Vaz, C.A.F.; Kleibert, A.; Nolting, F. [Swiss Light Source, Paul Scherrer Institut (PSI), Villigen CH-5232 (Switzerland)

2015-12-15

In situ X-ray photo-emission electron microscopy is used to investigate the magnetic properties of iron nanoparticles deposited on different single crystalline substrates, including Si(001), Cu(001), W(110), and NiO(001). We find that, in our room temperature experiments, Fe nanoparticles deposited on Si(001) and Cu(001) show both superparamagnetic and magnetically stable (blocked) ferromagnetic states, while Fe nanoparticles deposited on W(110) and NiO(001) show only superparamagnetic behaviour. The dependence of the magnetic behaviour of the Fe nanoparticles on the contact surface is ascribed to the different interfacial bonding energies, higher for W and NiO, and to a possible relaxation of point defects within the core of the nanoparticles on these substrates, that have been suggested to stabilise the ferromagnetic state at room temperature when deposited on more inert surfaces such as Si and Cu. - Highlights: • In situ X-ray photo-emission electron microscopy study on iron nanoparticles. • Magnetically blocked particles are found on Si(001) and Cu(001). • Superparamagnetic particles are found on W(110) and Ni0(001). • The substrate dependent behavior is ascribed to the different bonding energies.

Bio-synthesis of gold nanoparticles by human epithelial cells, in vivo

International Nuclear Information System (INIS)

Larios-Rodriguez, E; Rangel-Ayon, C; Herrera-Urbina, R; Castillo, S J; Zavala, G

2011-01-01

Healthy epithelial cells, in vivo, have the ability to synthesize gold nanoparticles when aqueous tetrachloroauric acid is made to react with human skin. Neither a reducing agent nor a protecting chemical is needed for this bio-synthesis method. The first indication of gold nanoparticle formation is the staining of the skin, which turns deep purple. Stereoscopic optical micrographs of human skin tissue in contact with aqueous tetrachloroauric acid clearly show the staining of the epithelial cells. The UV-Vis spectrum of these epithelial cells shows an absorption band with a maximum at 553 nm. This absorption peak is within the wavelength region where the surface plasmon resonance (SPR) band of aqueous colloidal gold exhibits a maximum. Transmission electron micrographs show that gold nanoparticles synthesized by epithelial cells have sizes between 1 and 100 nm. The electron diffraction pattern of these nanoparticles reveals a crystalline structure whose interplanar distances correspond to fcc metallic gold. Transmission electron micrographs of ultra-thin (70 nm thick) slices of epithelial cells clearly and undoubtedly demonstrate that gold nanoparticles are inside the cell. According to high resolution transmission electron micrographs of intracellular single gold nanoparticles, they have the shape of a polyhedron.

Bio-synthesis of gold nanoparticles by human epithelial cells, in vivo

Energy Technology Data Exchange (ETDEWEB)

Larios-Rodriguez, E; Rangel-Ayon, C; Herrera-Urbina, R [Departamento de Ingenieria Quimica y Metalurgia, Universidad de Sonora, Rosales y Luis Encinas S/N, Hermosillo, Sonora, C.P. 83000 (Mexico); Castillo, S J [Departamento de Investigacion en Fisica, Universidad de Sonora, Rosales y Luis Encinas S/N, Hermosillo, Sonora, C.P. 83000 (Mexico); Zavala, G, E-mail: elarios@polimeros.uson.mx [Instituto de Biotecnologia, Universidad Nacional Autonoma de Mexico, Cuernavaca, Morelos (Mexico)

2011-09-02

Healthy epithelial cells, in vivo, have the ability to synthesize gold nanoparticles when aqueous tetrachloroauric acid is made to react with human skin. Neither a reducing agent nor a protecting chemical is needed for this bio-synthesis method. The first indication of gold nanoparticle formation is the staining of the skin, which turns deep purple. Stereoscopic optical micrographs of human skin tissue in contact with aqueous tetrachloroauric acid clearly show the staining of the epithelial cells. The UV-Vis spectrum of these epithelial cells shows an absorption band with a maximum at 553 nm. This absorption peak is within the wavelength region where the surface plasmon resonance (SPR) band of aqueous colloidal gold exhibits a maximum. Transmission electron micrographs show that gold nanoparticles synthesized by epithelial cells have sizes between 1 and 100 nm. The electron diffraction pattern of these nanoparticles reveals a crystalline structure whose interplanar distances correspond to fcc metallic gold. Transmission electron micrographs of ultra-thin (70 nm thick) slices of epithelial cells clearly and undoubtedly demonstrate that gold nanoparticles are inside the cell. According to high resolution transmission electron micrographs of intracellular single gold nanoparticles, they have the shape of a polyhedron.

Atomistic computer simulations of FePt nanoparticles. Thermodynamic and kinetic properties

Energy Technology Data Exchange (ETDEWEB)

Mueller, M.

2007-12-20

In the present dissertation, a hierarchical multiscale approach for modeling FePt nanoparticles by atomistic computer simulations is developed. By describing the interatomic interactions on different levels of sophistication, various time and length scales can be accessed. Methods range from static quantum-mechanic total-energy calculations of small periodic systems to simulations of whole particles over an extended time by using simple lattice Hamiltonians. By employing these methods, the energetic and thermodynamic stability of non-crystalline multiply twinned FePt nanoparticles is investigated. Subsequently, the thermodynamics of the order-disorder transition in FePt nanoparticles is analyzed, including the influence of particle size, composition and modified surface energies by different chemical surroundings. In order to identify processes that reduce or enhance the rate of transformation from the disordered to the ordered state, the kinetics of the ordering transition in FePt nanoparticles is finally investigated by assessing the contributions of surface and volume diffusion. (orig.)

RNA aptamers targeted for human αA-crystallin do not bind αB-crystallin, and spare the α-crystallin domain.

Science.gov (United States)

Mallik, Prabhat K; Shi, Hua; Pande, Jayanti

2017-09-16

The molecular chaperones, α-crystallins, belong to the small heat shock protein (sHSP) family and prevent the aggregation and insolubilization of client proteins. Studies in vivo have shown that the chaperone activity of the α-crystallins is raised or lowered in various disease states. Therefore, the development of tools to control chaperone activity may provide avenues for therapeutic intervention, as well as enable a molecular understanding of chaperone function. The major human lens α-crystallins, αA- (HAA) and αB- (HAB), share 57% sequence identity and show similar activity towards some clients, but differing activities towards others. Notably, both crystallins contain the "α-crystallin domain" (ACD, the primary client binding site), like all other members of the sHSP family. Here we show that RNA aptamers selected for HAA, in vitro, exhibit specific affinity to HAA but do not bind HAB. Significantly, these aptamers also exclude the ACD. This study thus demonstrates that RNA aptamers against sHSPs can be designed that show high affinity and specificity - yet exclude the primary client binding region - thereby facilitating the development of RNA aptamer-based therapeutic intervention strategies. Copyright © 2017 Elsevier Inc. All rights reserved.

Chromosome dosimetry: the influence of culture media on the proliferation of irradiated and unirradiated human lymphocytes

International Nuclear Information System (INIS)

Purrott, R.J.; Lloyd, D.C.; Vulpis, N.

1981-01-01

The proliferation of phytohaemagglutinin stimulated human lymphocytes in four types of synthetic culture medium has been studied using the fluorescence plus Giemsa staining technique to determine cell cycle status. 48 hour cultures of unirradiated cells containing Ham's F10 or RPMI 1640 media yielded significant numbers of second cycle metaphases. Cultures containing Eagle's MEM or TC 199 media, however, required longer incubation times to produce appreciable numbers of second division cells. Intrinsic differences between donors in the rate of proliferation had little effect on the relative ranking of the media. Radiation induced mitotic delay of about 1 hour per Gray was observed for each medium. The relevance of these results to the accuracy of radiation dose estimation by chromosome aberration analysis is discussed. (author)

Synthesis, characterization and antibacterial study on the chitosan-functionalized Ag nanoparticles.

Science.gov (United States)

Biao, Linhai; Tan, Shengnan; Wang, Yuanlin; Guo, Ximin; Fu, Yujie; Xu, Fengjie; Zu, Yuangang; Liu, Zhiguo

2017-07-01

This study provided a facile, one-step hydrothermal method to synthesize stable Ag colloid in aqueous solution by utilizing chitosan as both reductant and stabilizer. The formation of chitosan-functionalized Ag nanoparticles was verified by UV-Vis, FTIR, TEM, AFM and XRD measurements. FTIR results revealed that the primary amine groups and amide groups of chitosan have specific interactions with the surface of Ag nanoparticles. The average diameter of the Ag nanoparticles is 10.0±5.4nm as determined by TEM. Ag nanoparticles are highly crystalline as revealed by HR-TEM and XRD measurements. The size and shape of Ag nanoparticles are also found to depend on the pH condition in the synthesis. Ag nanoparticles were the main products at pH5.0 whereas large Ag nanotriangle and truncated triangular nanoplate were dominant at pH4.0 in the synthesis. Due to its monodispersity and good stability, the chitosan-functionalized Ag colloid synthesized at pH5.0 was further tested for its antibacterial activities against gram-positive bacteria, gram-negative bacteria and fungus. The results of zone of inhibition, inhibition ratio and SEM characterization revealed that chitosan-functionalized Ag nanoparticles have great bactericidal efficiency against both bacteria and fungus. Copyright © 2017 Elsevier B.V. All rights reserved.

In situ growth of capping-free magnetic iron oxide nanoparticles on liquid-phase exfoliated graphene

NARCIS (Netherlands)

Tsoufis, T.; Syrgiannis, Z.; Akhtar, N.; Prato, M.; Katsaros, F.; Sideratou, Z.; Kouloumpis, A.; Gournis, D.; Rudolf, P.

2015-01-01

We report a facile approach for the in situ synthesis of very small iron oxide nanoparticles on the surface of high-quality graphene sheets. Our synthetic strategy involved the direct, liquid-phase exfoliation of highly crystalline graphite (avoiding any oxidation treatment) and the subsequent

The influence of Boron on creep-rupture behaviour of austenitic unstabilized and Nb-stabilized stainless steel X8CrNi 1613 in unirradiated and irradiated condition

International Nuclear Information System (INIS)

Sen, Susant Kumar.

1976-10-01

The present study deals with influence of boron on creep-rupture behaviour in unirradiated condition at 650 0 C along with precipitation behaviour, heat-treatment and recrystallization of unstabilized and stabilized steel. The results of creep-rupture tests on unirradiated specimens show that boron exerts a beneficial effect on the rupture life and ductility. Boron losses its beneficial effect on creep properties in unstabilized steel by prolong creeping. The magnitude of beneficial effect of Boron on creep properties depends upon the initial boron distribution which influences the number, size and distribution of the precipitates. Boron promotes the precipitation of type M 23 C 6 Carbides in the grain as well as at the grain boundary. Boron segregates in atomic form during slow cooling from austenitizing temperature. The recrystallization will be delayed by the presence of boron. The results of creep tests at 650 0 C shows that boron exerts a beneficial effect on creep life of irradiated steels. (orig./GSC) [de

Dissolution of unirradiated UO2 fuel in synthetic groundwater. Final report (1996-1998)

International Nuclear Information System (INIS)

Ollila, K.

1999-05-01

This study was a part of the EU R and D programme 1994-1998: Nuclear Fission Safety, entitled 'Source term for performance assessment of spent fuel as a waste form'. The research carried out at VTT Chemical Technology was focused on the effects of granitic groundwater composition and redox conditions on UO 2 solubility and dissolution mechanisms. The synthetic groundwater compositions simulated deep granitic fresh and saline groundwaters, and the effects of the near-field material, bentonite, on very saline groundwater. Additionally, the Spanish granite/bentonite water was used. The redox conditions (Eh), which are obviously the most important factors that influence on UO 2 solubility under the disposal conditions of spent fuel, varied from strongly oxidising (air-saturated), anaerobic (N 2 , O 2 2 , low Eh). The objective of the air-saturated dissolution experiments was to yield the maximum solution concentrations of U, and information on the formation of secondary phases that control the concentrations, with different groundwater compositions. The static batch solubility experiments of long duration (up to 1-2 years) were performed using unirradiated UO 2 pellets and powder. Under anaerobic and reducing conditions, the solubilities were also approached from oversaturation. The results of the oxic, air-saturated dissolution experiments with UO 2 powder showed that the increase in the salinity ( -5 M, were at the level of the theoretical solubility of schoepite or another uranyl oxide hydrate, e.g. becquerelite (possibly Na-polyuranate). The higher alkalinity of the fresh (Allard) composition increased the aqueous U concentration. Only some kind of oxidised U-phase (U 3 O 8 -UO 3 ) was identified with XRD when studying possible secondary phases after the contact time of one year with all groundwater compositions. Longer contact times are needed to identify secondary phases predicted by modelling (EQ3/6). In the anoxic dissolution experiments with UO 2 pellets, the

Synthesis of self-assembly plasmonic silver nanoparticles with tunable luminescence color

International Nuclear Information System (INIS)

Al-Ghamdi, Haifa S.; Mahmoud, Waleed E.

2014-01-01

Assembly is an elegant and effective bottom-up approach to prepare arrays of nanoparticles from nobel metals. Noble metal nanoparticles are perfect building blocks because they can be prepared with an adequate functionalization to allow their assembly and with controlled sizes. Herein, we report a novel recipe for the synthesis of self-assembled silver nanoparticles with tunable optical properties and sizes. The synthetic route followed here based on the covalent binding among silver nanoparticles by means of poly vinyl alcohol for the first time. The size of silver nanoparticle is governed by varying the amount of sodium borohydride. The as-synthesized nanoparticles were characterized by transmission electron microscopy, x-ray diffraction, energy dispersive x-ray spectroscopy, selected area electron diffraction and UV–vis spectroscopy. Results depicted that self-assembly of mono-dispersed silver nanoparticles with different sizes have been achieved. The silver nanostructure has a single crystalline faced centered cubic structure with growth orientation along (1 1 1) facet. These nanoparticles exhibited localized surface plasmon resonance at 403 nm. The luminescence peaks were red-sifted from violet to green due to the increase of the particle sizes. -- Highlights: • Self-assembled silver nanoparticles based PVA were synthesized. • NaBH 4 amount was found particle size dependent. • Silver nanoparticles strongly affected the surface plasmon resonance. • Highly symmetric luminescence emission band narrow width is obtained. • Dark field image showed a tunable color change from violet to green

CdSe nanoparticles grown via radiolytic methods in aqueous solutions

International Nuclear Information System (INIS)

Singh, Shalini; Rath, M.C.; Singh, A.K.; Mukherjee, T.; Jayakumar, O.D.; Tyagi, A.K.; Sarkar, S.K.

2011-01-01

Cadmium selenide, CdSe, nanoparticles have been synthesized in aqueous solution containing equimolar ammoniated CdSO 4 and Na 2 SeSO 3 as the starting materials without any capping agents, using gamma and electron beam irradiation under a reducing condition. The radiolytic processes occurring in water result in the formation of CdSe nanoparticles through the reactions mediated by hydrated electrons, e aq - . TEM measurements revealed that the CdSe nanoparticles were found to exist in agglomerates of dimension of about 100 nm, consisting of primary nanoparticles of dimensions within 5 nm. The as-grown nanoparticles were of cubic crystalline phase as supported by the XRD measurements. These bare CdSe nanoparticles exhibit room temperature ferromagnetic (RTFM) behavior. However, the RTFM behavior was found to be 30% higher in the case of CdSe nanoparticles prepared on electron beam irradiation as compared to those obtained by gamma irradiation, which was attributed to their relatively smaller size (2-3 nm) and disordered structures as compared to those obtained in the later case (3-5 nm). -- Research highlights: → CdSe nanoparticles could be synthesized in aqueous solutions containing equimolar ammoniated CdSO 4 and Na 2 SeSO 3 as the starting materials using gamma and electron beam irradiation under a reducing condition. → CdSe nanoparticles were found to exist in agglomerates of dimension of about 100 nm, consisting of primary nanoparticles of dimensions within 5 nm. → CdSe nanoparticles exhibit room temperature ferromagnetic (RTFM) behavior. → The RTFM behavior was found to be 30% higher in the case of CdSe nanoparticles prepared on electron beam irradiation as compared to those obtained by gamma irradiation.

Biofabrication of morphology improved cadmium sulfide nanoparticles using Shewanella oneidensis bacterial cells and ionic liquid: For toxicity against brain cancer cell lines.

Science.gov (United States)

Wang, Li; Chen, Siyuan; Ding, Yiming; Zhu, Qiang; Zhang, Nijia; Yu, Shuqing

2018-01-01

The present work determines the anticancer activity of bio-mediated synthesized cadmium sulfide nanoparticles using the ionic liquid and bacterial cells (Shewanella oneidensis). Bacterial cells have been exposed to be important resources that hold huge potential as ecofriendly, cost-effective, evading toxic of dangerous chemicals and the alternative of conventional physiochemical synthesis. The Shewanella oneidensis is an important kind of metal reducing bacterium, known as its special anaerobic respiratory and sulfate reducing capacity. The crystalline nature, phase purity and surface morphology of biosynthesized cadmium sulfide nanoparticles were analyzed by Fourier transform infrared spectroscopy, X-ray diffraction, Field emission scanning electron microscopy, Energy dispersive spectroscopy and Transmission electron microscopy. The use of imidazolium based ionic liquids as soft templating agent for controlling self-assembly and crystal growth direction of metal sulfide nanoparticles has also advanced as an important method. The microscopic techniques showed that the nanoparticles are designed on the nano form and have an excellent spherical morphology, due to the self-assembled mechanism of ionic liquid assistance. The antitumor efficiency of the cadmium sulfide nanoparticles was investigated against brain cancer cell lines using rat glioma cell lines. The effectively improved nano-crystalline and morphological structure of CdS nanoparticles in the presence of IL exhibit excellent cytotoxicity and dispersion ability on the cell shape is completely spread out showing a nice toxic environment against cancer cells. The cytotoxicity effect of cadmium sulfide nanoparticles was discussed with a diagrammatic representation. Copyright © 2017. Published by Elsevier B.V.

Green synthesis of silver nanoparticles and their characterization by XRD

Science.gov (United States)

Mehta, B. K.; Chhajlani, Meenal; Shrivastava, B. D.

2017-05-01

A cost effective and environment friendly technique for green synthesis of silver nanoparticles has been reported. Silver nanoparticles have been synthesized using ethanol extract of fruits of Santalum album (Family Santalaceae), commonly known as East Indian sandalwood. Fruits of S.album were collected and crushed. Ethanol was added to the crushed fruits and mixture was exposed to microwave for few minutes. Extract was concentrated by Buchi rotavaporator. To this extract, 1mM aqueous solution of silver nitrate (AgNO3) was added. After about 24 hr incubation Ag+ ions in AgNO3 solution were reduced to Ag atoms by the extract. Silver nanoparticles were obtained in powder form. X-ray diffraction (XRD) pattern of the prepared sample of silver nanoparticles was recorded The diffractogram has been compared with the standard powder diffraction card of JCPDS silver file. Four peaks have been identified corresponding to (hkl) values of silver. The XRD study confirms that the resultant particles are silver nanoparticles having FCC structure. The average crystalline size D, the value of the interplanar spacing between the atoms, d, lattice constant and cell volume have been estimated. Thus, silver nanoparticles with well-defined dimensions could be synthesized by reduction of metal ions due to fruit extract of S.album.

Antioxidant Effects of Quercetin and Catechin Encapsulated into PLGA Nanoparticles

Directory of Open Access Journals (Sweden)

Hector Pool

2012-01-01

Full Text Available Polymeric nanoparticles (PLGA have been developed for the encapsulation and controlled release of quercetin and catechin. Nanoparticles were fabricated using a solvent displacement method. Physicochemical properties were measured by light scattering, scanning electron microscopy and ζ-potential, X-ray diffraction, infrared spectroscopy and differential scanning calorimetry. Encapsulation efficiency and in vitro release profiles were obtained from differential pulse voltammetry experiments. Antioxidant properties of free and encapsulated flavonoids were determined by TBARS, fluorescence spectroscopy and standard chelating activity methods. Relatively small (d≈ 400 nm polymeric nanoparticles were obtained containing quercetin or catechin in a non-crystalline form (EE ≈ 79% and the main interactions between the polymer and each flavonoid were found to consist of hydrogen bonds. In vitro release profiles were pH-dependant, the more acidic pH, the faster release of each flavonoid from the polymeric nanoparticles. The inhibition of the action of free radicals and chelating properties, were also enhanced when quercetin and catechin were encapsulated within PLGA nanoparticles. The information obtained from this study will facilitate the design and fabrication of polymeric nanoparticles as possible oral delivery systems for encapsulation, protection and controlled release of flavonoids aimed to prevent oxidative stress in human body or food products.

Effect of Polyamide 6 on Crystalline Structure of Polymer in PVDF-Nanoclay Nanocomposite

Directory of Open Access Journals (Sweden)

Ali Akbar Yousefi

2012-12-01

Full Text Available The  effect  of  nanocaly  on  crystalline  structure  of  poly(vinylidene  fuoride, PVDF, and the morphology of the resulting nano-composite were investigated using  different  characterization  techniques.  The  presence  of  3wt%  Cloisite 30B in PVDF matrix results in 11 fold increase in the percentage of beta crystalline content of the polymer. This was found to be attributed to the epitaxial effect of the clay  surface. The  beta  crystalline  content  of  the  pure  polymer  (6% was  raised  to 68% in the composite. Addition of 5wt% polyamide 6 (PA6 improved dispersion of nanoclay which led to augmentation of the viscosity and displacement of the crossover frequency of the compatibilized composite towards lower frequencies. However, due to stronger affnity of the PA6 towards organically modifed clay the epitaxial effect of  the  clay on  crystalline  structure of PVDF was  totally  eliminated. The  reduction of  viscosity  in  incompatibilized  nanocomposite was  attributed  to  reduced  number of PVDF chain entanglements  in  the presence of nanoclay. Meanwhile,  increase  in viscosity and displacement of crossover  frequency  towards  lower  frequencies were attributed to formation of clay-PA nanoparticles and PVDF-polyamide 6 interactions. It is expected that the presence of polyamide 6 promotes the formation of oriented-beta crystals in PVDF, which in turn improves the piezoelectric properties of the polymer.

Microstructural evolution in modified 9Cr-1Mo ferritic/martensitic steel irradiated with mixed high-energy proton and neutron spectra at low temperatures

International Nuclear Information System (INIS)

Sencer, B.H.; Garner, F.A.; Gelles, D.S.; Bond, G.M.; Maloy, S.A.

2002-01-01

Modified 9Cr-1Mo ferritic/martensitic steel was exposed at 32-57 deg. C to a mixed proton/neutron particle flux and spectrum at the Los Alamos Neutron Science Center. The microstructure of unirradiated 9Cr-1Mo consists of laths, dislocations and carbides. Examination of electron diffraction patterns obtained from extraction replicas of unirradiated 9Cr-1Mo revealed that the precipitate microstructure was primarily dominated by M 23 C 6 carbides. The post-irradiation microstructure contained black-spot damage in addition to precipitates and dislocations. Examination of electron diffraction patterns revealed diffuse rings from M 23 C 6 carbides, indicating amorphization and/or nanocrystallinity. Crystalline MC carbides were also found. No cavity formation was found although a significant amount of helium and hydrogen generation had been generated. TEM-EDS examination of extraction replicas for carbides from unirradiated and irradiated samples did not show any detectable changes in composition of either M 23 C 6 or MC carbides. There was also no evident change in carbide size. Lattice images of M 23 C 6 carbides revealed an amorphous microstructure following irradiation, but MC carbides were still crystalline

Biosynthesis of silver nanoparticles by Pseudomonas spp. isolated from effluent of an electroplating industry.

Science.gov (United States)

Punjabi, Kapil; Yedurkar, Snehal; Doshi, Sejal; Deshapnde, Sunita; Vaidya, Shashikant

2017-08-01

The aim of this study was to isolate and screen bacteria from soil and effluent of electroplating industries for the synthesis of silver nanoparticles and characterize the potential isolate. Soil and effluent of electroplating industries from Mumbai were screened for bacteria capable of synthesizing silver nanoparticles. From two soils and eight effluent samples 20 bacterial isolates were obtained, of these, one was found to synthesize silver nanoparticles. Synthesis of silver nanoparticle by bacteria was confirmed by undertaking characterization studies of nanoparticles that involved spectroscopy and electron microscopic techniques. The potential bacteria was found to be Gram-negative short rods with its biochemical test indicating Pseudomonas spp . Molecular characterization of the isolate by 16S r DNA sequencing was carried out which confirmed its relation to Pseudomonas hibiscicola ATCC 19867. Stable nanoparticles synthesized were 50 nm in size and variable shapes as seen in SEM micrographs. The XRD and FTIR confirmed the crystalline structure of nanoparticles and presence of biomolecules mainly proteins as agents for reduction and capping of nanoparticles. The study demonstrates synthesis of nanoparticles by bacteria from effluent of electroplating industry. This can be used for large scale synthesis of nanoparticles by cost effective and environmentally benign mode of synthesis.

Flame spray synthesis under a non-oxidizing atmosphere: Preparation of metallic bismuth nanoparticles and nanocrystalline bulk bismuth metal

Energy Technology Data Exchange (ETDEWEB)

Grass, Robert N.; Stark, Wendelin J. [Institute for Chemical and Bioengineering, ETH Zuerich (Switzerland)], E-mail: wendelin.stark@chem.ethz.ch

2006-10-15

Metallic bismuth nanoparticles of over 98% purity were prepared by a modified flame spray synthesis method in an inert atmosphere by oxygen-deficient combustion of a bismuth-carboxylate based precursor. The samples were characterized by X-ray diffraction, thermal analysis and scanning electron microscopy confirming the formation of pure, crystalline metallic bismuth nanoparticles. Compression of the as-prepared powder resulted in highly dense, nanocrystalline pills with strong electrical conductivity and bright metallic gloss.

Multifunctional Eu3+- and Er3+/Yb3+-doped GdVO4 nanoparticles synthesized by reverse micelle method

OpenAIRE

Gavrilović, Tamara V.; Jovanović, Dragana J.; Lojpur, Vesna; Dramićanin, Miroslav D.

2014-01-01

Synthesis of Eu3+- and Er3+/Yb3+-doped GdVO4 nanoparticles in reverse micelles and their multifunctional luminescence properties are presented. Using cyclohexane, Triton X-100, and n-pentanol as the oil, surfactant, and co-surfactant, respectively, crystalline nanoparticles with ~4 nm diameter are prepared at low temperatures. The particle size assessed using transmission electron microscopy is similar to the crystallite size obtained from X-ray diffraction measurements, suggesting that each ...

Synthesis of Ag or Pt Nanoparticles by Hydrolysis of Either Ag2Na or PtNa

Directory of Open Access Journals (Sweden)

Huabin Wang

2008-01-01

Full Text Available Ag and Pt nanoparticles have successfully been synthesized by hydrolysis of either Ag2Na or PtNa at room temperature. The oxidation of sodium in the Pt-Na pellets was much faster than that in the Ag-Na pellets since Pt is a catalyst for H2O formation reaction from hydrogen and oxygen at room temperature. The hydrolysis byproduct, NaOH, has a high solubility and easily is removed. This method offers a simple method of preparing transition metal nanoparticles. The Ag and Pt nanoparticles prepared by this method were crystalline in nature, and spherical in shape with a mean size of around 10 nm.

Au nanoparticles attached carbon nanotubes as a high performance active element in field effect transistor

Energy Technology Data Exchange (ETDEWEB)

Lee, Myeongsoon; Kim, Don, E-mail: donkim@pknu.ac.kr

2016-08-15

The Au nanoparticles attached carbon nanotubes (Au-CNTs), diameter ranged from 40 to 250 nm, were prepared and discussed their chemical and electrical properties. The shape and crystallinity of the carbon nanotubes (CNTs) phase depended main2ly on the diameter of CNTs (r{sub Au-CNT}). Highly crystalline, straight CNTs were observed when the r{sub Au-CNT} exceeded 80 nm, and less crystalline noodle-shaped CNTs were observed when the r{sub Au-CNT} was smaller than 80 nm. The crystallinity of the CNT phase was confirmed by analyzing the G and D bands in their Raman spectra and the electrical conductivities of the Au-CNTs. The electrical conductivity of the highly crystalline carbon phase of Au-CNTs (r{sub Au-CNT} = 250 nm) was ∼10{sup 4} S/cm. The back-gated field effect transistors (FETs) based on the Au-CNTs, which were assembled on a SiO{sub 2}/Si wafer using the dielectrophoresis technique, showed that the Au-CNTs would be a good functional electronic material for future electronic and sensing applications. The transconductance and hole mobility of the FETs, which were assembled with the highly crystalline Au-CNTs (r{sub Au-CNT} = 250 nm), reached to 3.6 × 10{sup −4} A/V and 3.1 × 10{sup 4} cm{sup 2}/V s, respectively. These values are in the middle of those of reported for single walled carbon nanotubes and graphene. However, we could not find any field effect in a CNTFET, which assembled without Au nanoparticles, through the same process. - Highlights: • The shape and crystallinity of the CNTs depended mainly on the diameter of CNTs. • The electrical conductivity of the highly crystalline Au-CNTs was ∼10{sup 4} S/cm. • The Au-CNT FET shows typical p-channel gate effect with the on/off ratio of ∼10{sup 4}. • The Au-CNT FET shows very high transconductance (g{sub m}) and carrier mobility (μ{sub h}).

Au nanoparticles attached carbon nanotubes as a high performance active element in field effect transistor

International Nuclear Information System (INIS)

Lee, Myeongsoon; Kim, Don

2016-01-01

The Au nanoparticles attached carbon nanotubes (Au-CNTs), diameter ranged from 40 to 250 nm, were prepared and discussed their chemical and electrical properties. The shape and crystallinity of the carbon nanotubes (CNTs) phase depended main2ly on the diameter of CNTs (r_A_u_-_C_N_T). Highly crystalline, straight CNTs were observed when the r_A_u_-_C_N_T exceeded 80 nm, and less crystalline noodle-shaped CNTs were observed when the r_A_u_-_C_N_T was smaller than 80 nm. The crystallinity of the CNT phase was confirmed by analyzing the G and D bands in their Raman spectra and the electrical conductivities of the Au-CNTs. The electrical conductivity of the highly crystalline carbon phase of Au-CNTs (r_A_u_-_C_N_T = 250 nm) was ∼10"4 S/cm. The back-gated field effect transistors (FETs) based on the Au-CNTs, which were assembled on a SiO_2/Si wafer using the dielectrophoresis technique, showed that the Au-CNTs would be a good functional electronic material for future electronic and sensing applications. The transconductance and hole mobility of the FETs, which were assembled with the highly crystalline Au-CNTs (r_A_u_-_C_N_T = 250 nm), reached to 3.6 × 10"−"4 A/V and 3.1 × 10"4 cm"2/V s, respectively. These values are in the middle of those of reported for single walled carbon nanotubes and graphene. However, we could not find any field effect in a CNTFET, which assembled without Au nanoparticles, through the same process. - Highlights: • The shape and crystallinity of the CNTs depended mainly on the diameter of CNTs. • The electrical conductivity of the highly crystalline Au-CNTs was ∼10"4 S/cm. • The Au-CNT FET shows typical p-channel gate effect with the on/off ratio of ∼10"4. • The Au-CNT FET shows very high transconductance (g_m) and carrier mobility (μ_h).

The biotoxicity of hydroxyapatite nanoparticles to the plant growth.

Science.gov (United States)

Jiang, Hao; Liu, Jin-Ku; Wang, Jian-Dong; Lu, Yi; Zhang, Min; Yang, Xiao-Hong; Hong, Dan-Jing

2014-04-15

In the present study, hydroxyapatite (HAP) nanoparticles of different particle sizes with high crystallinity and similiar structure were prepared by hydrothermal method. The crystal structure and particle size were characterized by X-ray diffraction pattern (XRD), transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR) spectroscopy. Mung bean sprouts were first used as experimental models. Instead of by MTT assay, the cytoxicity of HAP nanoparticles were proved and evaluated by measuring the hypocotyle length of mung bean sprouts in the culture media. The result showed that the inhibition effect to the growth of mung bean sprouts enhanced when HAP nanoparticles existed. Culture media of HAP nanoparticles with different concentrations and particle sizes was prepared to investigate the level of inhibition effect to the growth of mung bean sprouts. The result found that hypocotyl length of mung bean sprouts were the shortest cultured in 5mg/mL culture media in which the HAP nanoparticles were prepared by hydrothermal method for 24h. It was concluded the inhibition effect depended on the amount of intracellular HAP nanoparticles. The nanostructure and Ca(2+) concentration were considered as the main factors to cause cell apoptosis which was the reason of inhibition. The study provided a preliminary perspective about biotoxicity of HAP nanomaterials to the plant growth. Copyright © 2014 Elsevier B.V. All rights reserved.

Size-dependent structure of silver nanoparticles under high pressure

Energy Technology Data Exchange (ETDEWEB)

Koski, Kristie Jo [Univ. of California, Berkeley, CA (United States)

2008-12-31

Silver noble metal nanoparticles that are<10 nm often possess multiply twinned grains allowing them to adopt shapes and atomic structures not observed in bulk materials. The properties exhibited by particles with multiply twinned polycrystalline structures are often far different from those of single-crystalline particles and from the bulk. I will present experimental evidence that silver nanoparticles<10 nm undergo a reversible structural transformation under hydrostatic pressures up to 10 GPa. Results for nanoparticles in the intermediate size range of 5 to 10 nm suggest a reversible linear pressure-dependent rhombohedral distortion which has not been previously observed in bulk silver. I propose a mechanism for this transitiion that considers the bond-length distribution in idealized multiply twinned icosahedral particles. Results for nanoparticles of 3.9 nm suggest a reversible linear pressure-dependent orthorhombic distortion. This distortion is interpreted in the context of idealized decahedral particles. In addition, given these size-dependent measurements of silver nanoparticle compression with pressure, we have constructed a pressure calibration curve. Encapsulating these silver nanoparticles in hollow metal oxide nanospheres then allows us to measure the pressure inside a nanoshell using x-ray diffraction. We demonstrate the measurement of pressure gradients across nanoshells and show that these nanoshells have maximum resolved shear strengths on the order of 500 MPa to IGPa.

Anticancer and enhanced antimicrobial activity of biosynthesizd silver nanoparticles against clinical pathogens

Science.gov (United States)

Rajeshkumar, Shanmugam; Malarkodi, Chelladurai; Vanaja, Mahendran; Annadurai, Gurusamy

2016-07-01

The present investigation shows the biosynthesis of eco-friendly silver nanoparticles using culture supernatant of Enterococcus sp. and study the effect of enhanced antimicrobial activity, anticancer activity against pathogenic bacteria, fungi and cancer cell lines. Silver nanoparticles was synthesized by adding 1 mM silver nitrate into the 100 ml of 24 h freshly prepared culture supernatant of Enterococcus sp. and were characterized by UV-vis spectroscopy, X-ray diffraction (XRD), Transmission Electron Microscope (TEM), Selected Area Diffraction X-Ray (SAED), Energy Dispersive X Ray (EDX) and Fourier Transform Infra red Spectroscopy (FT-IR). The synthesized silver nanoparticles were impregnated with commercial antibiotics for evaluation of enhanced antimicrobial activity. Further these synthesized silver nanoparticles were assessed for its anticancer activity against cancer cell lines. In this study crystalline structured nanoparticles with spherical in the size ranges from 10 to 80 nm and it shows excellent enhanced antimicrobial activity than the commercial antibiotics. The in vitro assay of silver nanoparticles on anticancer have great potential to inhibit the cell viability. Amide linkages and carboxylate groups of proteins from Enterococcus sp. may bind with silver ions and convert into nanoparticles. The activities of commercial antibiotics were enhanced by coating silver nanoparticles shows significant improved antimicrobial activity. Silver nanoparticles have the great potential to inhibit the cell viability of liver cancer cells lines (HepG2) and lung cancer cell lines (A549).

Synthesis and structures of Al–Ti nanoparticles by hydrogen plasma-metal reaction

International Nuclear Information System (INIS)

Liu Tong; Zhang Tongwen; Zhu Mu; Qin Chenggong

2012-01-01

Three kinds of Al–Ti nanoparticles (7.7, 27.8, and 42.6 at.% Ti) have been prepared from Al–65, Al–85, and Al–88 at.% Ti master alloys by hydrogen plasma-metal reaction, with average particle sizes of 30, 25, and 80 nm, respectively. The higher evaporation rate of Al than Ti resulted in the low Ti contents in the nanoparticles than those in the master alloys. Microscopy observation revealed that the primary nanoparticles are spherical in shape, and occur as chain aggregates of several individual nanoparticles due to the faster collision rate than the coalescence rate. All the Al–Ti nanoparticles contain amorphous alumina layers of about 2–3 nm in thickness surrounding the crystalline core. AlTi intermetallic nanoparticles were successfully produced for Al–27.8 at.% Ti, with a single crystal of AlTi in one chain aggregate. The composite nanoparticles of Al together with some Al 3 Ti phases are prepared for Al–7.7 at.% Ti, with each phase in the individual particle of one chain aggregate. The composite nanoparticles of AlTi with some AlTi 3 were produced for Al–42.6 at.% Ti, with each phase in the individual particle of one chain aggregate. The formation mechanism of Al–Ti nanoparticles was interpreted in terms of phase transition and the effect of hydrogen.

Effect of cobalt doping on crystallinity, stability, magnetic and optical properties of magnetic iron oxide nano-particles

Energy Technology Data Exchange (ETDEWEB)

Anjum, Safia, E-mail: safia_anjum@hotmail.com [Department of Physics, Lahore College for Women University, Lahore (Pakistan); Tufail, Rabia [Department of Physics, Lahore College for Women University, Lahore (Pakistan); Rashid, Khalid [PCSIR Laboratories Lahore (Pakistan); Zia, Rehana [Department of Physics, Lahore College for Women University, Lahore (Pakistan); Riaz, S. [Centre for Solid State Physics, University of the Punjab, Lahore (Pakistan)

2017-06-15

Highlights: • The stability of Co{sub x}Fe{sub (2-x)}O{sub 3} nanoparticles enhances. • Energy losses increases. • Anisotropy of NP is high. - Abstract: This paper is dedicated to investigate the effect of Co{sup 2+} ions in magnetite Fe{sub 3}O{sub 4} nano-particles with stoichiometric formula Co{sub x}Fe{sub 3-x}O{sub 4} where (x = 0, 0.05, 0.1 and 0.15) prepared by co-precipitation method. The structural, thermal, morphological, magnetic and optical properties of magnetite and Co{sup 2+} doped magnetite nanoparticles have been carried out using X-ray Diffractometer, Fourier Transform Infrared Spectroscopy, Themogravimetric Analysis, Scanning Electron Microscopy, Vibrating Sample Magnetometer (VSM) and UV–Vis Spectrometer (UV–Vis) respectively. Structural analysis verified the formation of single phase inverse spinel cubic structure with decrease in lattice parameters due to increase in cobalt content. FTIR analysis confirms the single phase of Co{sub x}Fe{sub 3-x}O{sub 4} nanoparticles with the major band at 887 cm{sup −1}, which might be due to the stretching vibrations of metal-oxide bond. The DSC results corroborate the finding of an increase in the maghemite to hematite phase transition temperature with increase in Co{sup 2+} content. The decrease in enthalpy with increase in Co{sup 2+} concentration attributed to the fact that the degree of conversion from maghemite to hematite decrease which shows that the stability increases with increasing Co{sup 2+} content in B-site of Fe{sub 3}O{sub 4} structure. SEM analysis demonstrated the formation of spherical shaped nanoparticles with least agglomeration. The magnetic measurements enlighten that the coercivity and anisotropy of Co{sub x}Fe{sub 3-x}O{sub 4} nanoparticles are significantly increased. From UV–Vis analysis it is revealed that band gap energy increases with decreasing particle size. This result has a great interest for magnetic fluid hyperthermia application (MPH).

Low-temperature solid-state synthesis and optical properties of CdS-ZnS and ZnS-CdS alloy nanoparticles

International Nuclear Information System (INIS)

Liu Jinsong; Zhao Chuanbao; Li Ziquan; Chen Jiankang; Zhou Hengzhi; Gu Shanqun; Zeng Youhong; Li Yongchan; Huang Yongbing

2011-01-01

Highlights: → Using a simple low-temperature solid-state synthetic method, ZnS-CdS and CdS-ZnS alloy nanoparticles were obtained, respectively. → The size of the nanoparticles increased with increasing reaction temperature, and reaction sequence had no effect on the size of the nanoparticles under the same temperature. → The particle diameters of the CdS-ZnS products decreased gradually with increasing Cd 2+ /Zn 2+ molar ratio, whereas those of the ZnS-CdS products increased gradually with increasing Zn 2+ /Cd 2+ molar ratio. → The study shows that sufficient grinding and crystalline water may be a key in forming the alloy nanoparticles. → Optical properties of the products depend on reaction temperature, reactant addition sequence, and reactant molar ratio. - Abstract: A simple low-temperature solid-state synthetic method was employed to obtain ZnS-CdS and CdS-ZnS alloy nanoparticles. The effects of reaction sequence, reactant molar ratios, and synthesis temperature on the products were investigated. The crystal structure and morphology of the products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and fourier transform infrared (FT-IR) spectroscopy. The results show that the products are alloy nanoparticles with a cubic phase structure. The formation mechanism of the alloy nanoparticles is briefly discussed. Sufficient grinding and crystalline water may be essential to form alloy nanoparticles. Ultraviolet-visible (UV-vis) spectra show that the edge absorptions of the CdS-ZnS and ZnS-CdS nanoparticles were located between those of ZnS and CdS bulks, and the absorbance at the peak maximum was practically dependent on reaction temperature, reaction sequence, and molar ratio. Extrinsic deep-level emission resulted in strong peaks in the photoluminescence (PL) spectra. The position and intensity of the emission peaks varied with the conditions during synthesis.

Anticancer activity of Ficus religiosa engineered copper oxide nanoparticles

International Nuclear Information System (INIS)

Sankar, Renu; Maheswari, Ramasamy; Karthik, Selvaraju; Shivashangari, Kanchi Subramanian; Ravikumar, Vilwanathan

2014-01-01

The design, synthesis, characterization and application of biologically synthesized nanomaterials have become a vital branch of nanotechnology. There is a budding need to develop a method for environmentally benign metal nanoparticle synthesis, that do not use toxic chemicals in the synthesis protocols to avoid adverse effects in medical applications. Here, it is a report on an eco-friendly process for rapid synthesis of copper oxide nanoparticles using Ficus religiosa leaf extract as reducing and protecting agent. The synthesized copper oxide nanoparticles were confirmed by UV–vis spectrophotometer, absorbance peaks at 285 nm. The copper oxide nanoparticles were analyzed with field emission-scanning electron microscope (FE-SEM), Fourier transform infrared (FT-IR) spectroscopy, dynamic light scattering (DLS) and X-ray diffraction (XRD) spectrum. The FE-SEM and DLS analyses exposed that copper oxide nanoparticles are spherical in shape with an average particle size of 577 nm. FT-IR spectral analysis elucidates the occurrence of biomolecules required for the reduction of copper oxide ions. Zeta potential studies showed that the surface charge of the formed nanoparticles was highly negative. The XRD pattern revealed that synthesized nanoparticles are crystalline in nature. Further, biological activities of the synthesized nanoparticles were confirmed based on its stable anti-cancer effects. The apoptotic effect of copper oxide nanoparticles is mediated by the generation of reactive oxygen species (ROS) involving the disruption of mitochondrial membrane potential (Δψm) in A549 cells. The observed characteristics and results obtained in our in vitro assays suggest that the copper nanoparticles might be a potential anticancer agent. - Highlights: • Biogenic synthesis of copper oxide nanoparticles by leaf extract of Ficus religiosa • Characterized via UV–vis, FT-IR, DLS, FE-SEM with EDAX and XRD • Protein may act as an encapsulating, reducing and stabilizing

Anticancer activity of Ficus religiosa engineered copper oxide nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Sankar, Renu; Maheswari, Ramasamy; Karthik, Selvaraju [Department of Biochemistry, School of Life Sciences, Bharathidasan University, Tiruchirappalli 620 024, Tamilnadu (India); Shivashangari, Kanchi Subramanian, E-mail: shivashangari@gmail.com [Regional Forensic Science Laboratory, Tiruchirapalli, Tamilnadu (India); Ravikumar, Vilwanathan, E-mail: ravikumarbdu@gmail.com [Department of Biochemistry, School of Life Sciences, Bharathidasan University, Tiruchirappalli 620 024, Tamilnadu (India)

2014-11-01

The design, synthesis, characterization and application of biologically synthesized nanomaterials have become a vital branch of nanotechnology. There is a budding need to develop a method for environmentally benign metal nanoparticle synthesis, that do not use toxic chemicals in the synthesis protocols to avoid adverse effects in medical applications. Here, it is a report on an eco-friendly process for rapid synthesis of copper oxide nanoparticles using Ficus religiosa leaf extract as reducing and protecting agent. The synthesized copper oxide nanoparticles were confirmed by UV–vis spectrophotometer, absorbance peaks at 285 nm. The copper oxide nanoparticles were analyzed with field emission-scanning electron microscope (FE-SEM), Fourier transform infrared (FT-IR) spectroscopy, dynamic light scattering (DLS) and X-ray diffraction (XRD) spectrum. The FE-SEM and DLS analyses exposed that copper oxide nanoparticles are spherical in shape with an average particle size of 577 nm. FT-IR spectral analysis elucidates the occurrence of biomolecules required for the reduction of copper oxide ions. Zeta potential studies showed that the surface charge of the formed nanoparticles was highly negative. The XRD pattern revealed that synthesized nanoparticles are crystalline in nature. Further, biological activities of the synthesized nanoparticles were confirmed based on its stable anti-cancer effects. The apoptotic effect of copper oxide nanoparticles is mediated by the generation of reactive oxygen species (ROS) involving the disruption of mitochondrial membrane potential (Δψm) in A549 cells. The observed characteristics and results obtained in our in vitro assays suggest that the copper nanoparticles might be a potential anticancer agent. - Highlights: • Biogenic synthesis of copper oxide nanoparticles by leaf extract of Ficus religiosa • Characterized via UV–vis, FT-IR, DLS, FE-SEM with EDAX and XRD • Protein may act as an encapsulating, reducing and stabilizing

New Nanoparticles Dispersing Beads Mill with Ultra Small Beads and its Application

International Nuclear Information System (INIS)

Inkyo, M; Tahara, T; Imajyo, Y

2011-01-01

Two of the major problems related to nanoparticle dispersion with a conventional beads mill are re-agglomeration and damage to the crystalline structure of the particles. The Ultra Apex Mill was developed to solve these problems by enabling the use of ultra-small beads with a diameter of less than 0.1mm. The core of this breakthrough development is centrifugation technology which allows the use of beads as small as 0.015mm. When dispersing agglomerated nanoparticles the impulse of the small beads is very low which means there is little influence on the particles. The surface energy of the nanoparticles remains low so the properties are not likely to change. As a result, stable nanoparticle dispersions can be achieved without re-cohesion. The Ultra Apex Mill is superior to conventional beads mills that are limited to much larger bead sizes. The technology of the Ultra Apex Mill has pioneered practical applications for nanoparticles in various fields: composition materials for LCD screens, ink-jet printing, ceramic condensers and cosmetics.

Response of unirradiated and irradiated PWR fuel rods tested under power-cooling-mismatch conditions

International Nuclear Information System (INIS)

MacDonald, P.E.; Quapp, W.J.; Martinson, Z.R.; McCardell, R.K.; Mehner, A.S.

1978-01-01

This report summarizes the results from the single-rod power-cooling-mismatch (PCM) and irradiation effects (IE) tests conducted to date in the Power Burst Facility (PBF) at the U.S. DOE Idaho National Engineering Laboratory. This work was performed for the U.S. NRC under contact to the Department of Energy. These tests are part of the NRC Fuel Behavior Program, which is designed to provide data for the development and verification of analytical fuel behavior models that are used to predict fuel response to abnormal or postulated accident conditions in commercial LWRs. The mechanical, chemical and thermal response of both previously unirradiated and previously irradiated LWR-type fuel rods tested under power-cooling-mismatch condition is discussed. A brief description of the test designs is presented. The results of the PCM thermal-hydraulic studies are summarized. Primary emphasis is placed on the behavior of the fuel and cladding during and after stable film boiling. (orig.) [de

Overview and Critical Assessment of the Tensile Properties of unirradiated and irradiated EUROFER97

Energy Technology Data Exchange (ETDEWEB)

Lucon, E.; Vandermeulen, W.

2007-10-15

Material research represents a crucial issue for the assessment of fusion as a future viable source of energy. Structural materials, in particular, need to show a superior mechanical and chemical behaviour to guarantee the safe operation of the reactor during its whole lifetime, while retaining low activation characteristics to minimise the environmental impact of the produced waste. In this context, specific efforts have been focused for the last twenty years in Europe, Japan and the US, on developing suitable Reduced Activation Ferritic Martensitic (RAFM) steels as candidate structural materials. EUROFER97 has recently emerged in Europe as the reference material for the DEMO design. In the framework of the Long-Term Programme of EFDA (European Fusion Development Agreement), a coordinated effort has been launched aimed at providing a critical assessment of the mechanical and microstructural properties of EUROFER97 in the unirradiated and irradiated conditions, based on the results accumulated since the late 90ies within numerous EFDA tasks.

Liquid crystalline order in polymers

CERN Document Server

Blumstein, Alexandre

1978-01-01

Liquid Crystalline Order in Polymers examines the topic of liquid crystalline order in systems containing rigid synthetic macromolecular chains. Each chapter of the book provides a review of one important area of the field. Chapter 1 discusses scattering in polymer systems with liquid crystalline order. It also introduces the field of liquid crystals. Chapter 2 treats the origin of liquid crystalline order in macromolecules by describing the in-depth study of conformation of such macromolecules in their unassociated state. The chapters that follow describe successively the liquid crystalli

Preparation of high surface area and high conductivity polyaniline nanoparticles using chemical oxidation polymerization technique

Science.gov (United States)

Budi, S.; Yusmaniar; Juliana, A.; Cahyana, U.; Purwanto, A.; Imaduddin, A.; Handoko, E.

2018-03-01

In this work, polyaniline nanoparticles were synthesized using a chemical oxidation polymerization technique. The ammonium peroxydisulfate (APS)/aniline ratio, APS dropping time, and polymerization temperature were optimized to increase the surface area and conductivity of the polyaniline.The Fourier-transform infrared (FTIR) spectrum confirmed the formation of emeraldine salt polyaniline. X-ray diffraction (XRD) patterns indicated that amorphous and crystalline phases of the polyaniline were formed with crystallinity less than 40%. Scanning electron microscope (SEM) micrographs showed that the finest nanoparticles with uniform size distribution were obtained at the polymerization temperature of 0°C. A surface area analyzer (SAA) showed that the highest Brunauer-Emmett-Teller surface area (SBET ) of 42.14 m2/gwas obtained from an APS/aniline ratio of 0.75 with a dropping time of 0 s at a polymerization temperature of 0°C. A four-point probe measurement conducted at 75–300K indicated relatively high conductivity of the semiconductor characteristic of the polyaniline.

Storage for the Fast Flux Test Facility unirradiated fuel in the Plutonium Finishing Plant Complex, Hanford Site, Richland, Washington

International Nuclear Information System (INIS)

1992-01-01

This Environmental Assessment evaluates the proposed action to relocate and store unirradiated Fast Flux Test Facility fuel in the Plutonium Finishing Plant Complex on the Hanford Site, Richland, Washington. The US Department of Energy has decided to cease fuel fabrication activities in the 308 Building in the 300 Area. This decision was based on a safety concern over the ability of the fuel fabrication portion of the 308 Building to withstand a seismic event. The proposed action to relocate and store the fuel is based on the savings that could be realized by consolidating security costs associated with storage of the fuel. While the 308 Building belowgrade fuel storage areas are not at jeopardy by a seismic event, the US Department of Energy is proposing to cease storage operations along with the related fabrication operations. The US Department of Energy proposes to remove the unirradiated fuel pins and fuel assemblies from the 308 Building and store them in Room 192A, within the 234-5Z Building, a part of the Plutonium Finishing Plant Complex, located in the 200 West Area. Minor modifications to Room 192A would be required to accommodate placement of the fuel. The US Department of Energy estimates that removing all of the fuel from the 308 Building would save $6.5 million annually in security expenditures for the Fast Flux Test Facility. Environmental impacts of construction, relocation, and operation of the proposed action and alternatives were evaluated. This evaluation concluded that the proposed action would have no significant impacts on the human environment

Magnetite Nanoparticles Coated with Rifampicin and Chlortetracycline for Drug Delivery Applications

International Nuclear Information System (INIS)

Nadejde, Claudia; Ciurlica, Ecaterina Foca-nici; Creanga, Dorina; Carlescu, Aurelian; Badescu, Vasile

2010-01-01

Four types of biocompatible magnetic fluids based on superparamagnetic nanoparticles with Fe 3 O 4 cores were functionalized with antibiotics (rifampicin or chlortetracycline) as potential candidates for in vivo biomedical applications, such as magnetically controlled drug delivery. The synthesis consisted in coprecipitation of iron oxide in basic, as well as in acid medium, followed by the dispersion of the resulted magnetite nanoparticles in aqueous solution containing the antibiotic. The chosen method to prepare the magnetite-core/drug-shell systems avoided intermediate organic coating of the magnetic nanoparticles. Comparative analysis of the rheological features of the aqueous magnetic fluid samples was performed. The structural features of the coated magnetic particles were investigated by X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and Vibrating Sample Magnetometry (VSM). Good crystallinity and adequate stability in time were evidenced. Drug delivery curves were spectrophotometrically provided.

Spectroscopic and magnetic studies of highly dispersible superparamagnetic silica coated magnetite nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Tadyszak, Krzysztof [NanoBioMedical Centre, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznań (Poland); Institute of Molecular Physics Polish Academy of Sciences, ul. Mariana Smo.luchowskiego 17, 60-179 Poznań (Poland); Kertmen, Ahmet, E-mail: ahmet.kertmen@pg.gda.pl [Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk (Poland); Coy, Emerson [NanoBioMedical Centre, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznań (Poland); Andruszkiewicz, Ryszard; Milewski, Sławomir [Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk (Poland); Kardava, Irakli; Scheibe, Błażej; Jurga, Stefan [NanoBioMedical Centre, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznań (Poland); Chybczyńska, Katarzyna, E-mail: katarzyna.chybczynska@ifmpan.poznan.pl [Institute of Molecular Physics Polish Academy of Sciences, ul. Mariana Smo.luchowskiego 17, 60-179 Poznań (Poland)

2017-07-01

Highlights: • Superparamagnetic core-shell nanoparticles of Fe{sub 2}O{sub 3}@Silica were obtained. • Magnetic response was studied by DC, AC magnetometry and EPR spectroscopy. • Nanoparticles show magnetite structure with a well-defined Verwey transition. • Samples show no inter particle magnetic interactions or agglomeration. - Abstract: Superparamagnetic behavior in aqueously well dispersible magnetite core-shell Fe{sub 3}O{sub 4}@SiO{sub 2} nanoparticles is presented. The magnetic properties of core-shell nanoparticles were measured with use of the DC, AC magnetometry and EPR spectroscopy. Particles where characterized by HR-TEM and Raman spectroscopy, showing a crystalline magnetic core of 11.5 ± 0.12 nm and an amorphous silica shell of 22 ± 1.5 nm in thickness. The DC, AC magnetic measurements confirmed the superparamagnetic nature of nanoparticles, additionally the EPR studies performed at much higher frequency than DC, AC magnetometry (9 GHz) have confirmed the paramagnetic nature of the nanoparticles. Our results show the excellent magnetic behavior of the particles with a clear magnetite structure, which are desirable properties for environmental remediation and biomedical applications.

Interaction of spermine with DNA, vitamin C and bovine serum albumin in the unirradiated and gamma irradiated states

International Nuclear Information System (INIS)

Upadhyay, S.N.; Lal, C.; Bhardwaj, R.; Chaturvedi, S.; Chaudhury, N.K.

2006-01-01

Structural deformability of spermine with radiation dose (maximum 10 Gy) has been proved. Complex formation of spermine with DNA, vitamin C and BSA took place. Calibration and radiation-induced absorption changes in spermine by ninhydrin reagent has been followed quantitatively. Interaction of vitamin C with DNA and their radiation-induced changes have been reported. Interaction of spermine with DNA in the unirradiated and gamma irradiated states in 10 -3 M phosphate buffer and water have been compared. Addition of spermine and vitamin C to DNA makes DNA structure more condensed. Bovine serum albumin also binds with spermine and protects it from radiation-induced degradation. (author)

Solubility of unirradiated UO2 fuel in aqueous solutions. Comparison between experimental and calculated (EQ3/6) data

International Nuclear Information System (INIS)

Ollila, K.

1995-11-01

The solubility behaviour of unirradiated UO 2 pellets was studied under oxic (air-saturated) and anoxic (N 2 ) conditions in deionized water, in sodium bicarbonate solutions with varying bicarbonate content (60 - 600 ppm), in Allard groundwater simulating granitic fresh groundwater conditions, and in bentonite water simulating the effects of bentonite on granitic fresh groundwater (25 deg C). The release of uranium was measured during static batch dissolution experiments of long duration (2-6 years). A comparison was made with the theoretical solubility data calculated with the geochemical code EQ3/6 in order to evaluate solubility (steady state) limiting factors. (orig.) (26 refs., 32 figs., 13 tabs.)

Investigations of cations distributions and morphology of cobalt ferrite magnetic nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Chandekar, Kamlesh V., E-mail: chandekar.kamlex@gmail.com; Kant, K. Mohan [Dept. of Applied Physics, Visvesvaraya National Institute of Technology, Nagpur, - 440010 (India)

2016-05-06

Cobalt ferrite nanoparticles were synthesized by co-precipitation method and structural properties was investigated by X-ray diffraction (XRD) at room temperature. X-ray diffraction data was used to determine lattice parameter, X-ray density, distributions of cations among tetrahedral and octahedral sites, site radii, ionic radii and bond length of inverse spinel cobalt ferrite. XRD analysis revealed crystallinity and high intense peak correspond to cubic inverse spinel structure with average crystalline size measured by X-ray line profile fitting was found to be 13nm for most intense peak (311). The surface morphology and microstructural feature was investigated by TEM analysis which revealed that particle size varying from 12-22 nm with selected electron diffraction pattern (SAED).

Luminescence study on Eu3+ doped Y2O3 nanoparticles: particle size, concentration and core-shell formation effects

International Nuclear Information System (INIS)

Singh, L Robindro; Ningthoujam, R S; Sudarsan, V; Srivastava, Iti; Singh, S Dorendrajit; Dey, G K; Kulshreshtha, S K

2008-01-01

Nanoparticles of Eu 3+ doped Y 2 O 3 (core) and Eu 3+ doped Y 2 O 3 covered with Y 2 O 3 shell (core-shell) are prepared by urea hydrolysis for 3 h in ethylene glycol medium at a relatively low temperature of 140 deg. C, followed by heating at 500 and 900 deg. C. Particle sizes determined from x-ray diffraction and transmission electron microscopic studies are 11 and 18 nm for 500 and 900 deg. C heated samples respectively. Based on the luminescence studies of 500 and 900 deg. C heated samples, it is confirmed that there is no particle size effect on the peak positions of Eu 3+ emission, and optimum luminescence intensity is observed from the nanoparticles with a Eu 3+ concentration of 4-5 at.%. A luminescence study establishes that the Eu 3+ environment in amorphous Y (OH) 3 is different from that in crystalline Y 2 O 3 . For a fixed concentration of Eu 3+ doping, there is a reduction in Eu 3+ emission intensity for core-shell nanoparticles compared to that of core nanoparticles, and this has been attributed to the concentration dilution effect. Energy transfer from the host to Eu 3+ increases with increase of crystallinity

Influence of formulation and processing variables on properties of itraconazole nanoparticles made by advanced evaporative precipitation into aqueous solution.

Science.gov (United States)

Bosselmann, Stephanie; Nagao, Masao; Chow, Keat T; Williams, Robert O

2012-09-01

Nanoparticles, of the poorly water-soluble drug, itraconazole (ITZ), were produced by the Advanced Evaporative Precipitation into Aqueous Solution process (Advanced EPAS). This process combines emulsion templating and EPAS processing to provide improved control over the size distribution of precipitated particles. Specifically, oil-in-water emulsions containing the drug and suitable stabilizers are sprayed into a heated aqueous solution to induce precipitation of the drug in form of nanoparticles. The influence of processing parameters (temperature and volume of the heated aqueous solution; type of nozzle) and formulation aspects (stabilizer concentrations; total solid concentrations) on the size of suspended ITZ particles, as determined by laser diffraction, was investigated. Furthermore, freeze-dried ITZ nanoparticles were evaluated regarding their morphology, crystallinity, redispersibility, and dissolution behavior. Results indicate that a robust precipitation process was developed such that size distribution of dispersed nanoparticles was shown to be largely independent across the different processing and formulation parameters. Freeze-drying of colloidal dispersions resulted in micron-sized agglomerates composed of spherical, sub-300-nm particles characterized by reduced crystallinity and high ITZ potencies of up to 94% (w/w). The use of sucrose prevented particle agglomeration and resulted in powders that were readily reconstituted and reached high and sustained supersaturation levels upon dissolution in aqueous media.

Triton X-100 functionalized Fe3O4 nanoparticles for biomedical applications

Science.gov (United States)

Gawali, Santosh L.; Madan, Devendra P.; Barick, K. C.; Somani, R.; Hassan, P. A.

2018-04-01

We report the preparation of Triton X-100 functionalized Fe3O4 nanoparticles (TXMNPs) and investigated their potential application in hyperthermia therapy. The formation of highly crystalline, spinel-structured Fe3O4 nanoparticles of average size of about 10 nm was evident from X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses. Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), UV-visible spectroscopy and zeta-potential measurements suggest the successful functionalization of nanoparticles with TX-100. These TXMNPs exhibit good colloidal stabilization in aqueous medium and show protein resistance characteristic in physiological medium. They showed excellent heating efficacy under AC magnetic field (AMF) with specific absorption rate (SAR) values of 146 and 260 W/g of Fe for 1.25 and 0.625 mg/ml of Fe, respectively at an applied AMF of 507 Oe and frequency of 300 kHz. Thus, these nanoparticles can be used as effective thermoseed for hyperthermia treatment of cancer.

Effect of calcination temperature on the H{sub 2}O{sub 2} decomposition activity of nano-crystalline Co{sub 3}O{sub 4} prepared by combustion method

Energy Technology Data Exchange (ETDEWEB)

Makhlouf, M.Th. [Chemistry Department, Faculty of Science, Assiut University, 71516 Assiut (Egypt); Abu-Zied, B.M., E-mail: babuzied@aun.edu.eg [Chemistry Department, Faculty of Science, Assiut University, 71516 Assiut (Egypt); Mansoure, T.H. [Chemistry Department, Faculty of Science, Assiut University, 71516 Assiut (Egypt)

2013-06-01

Cobalt oxide nano-particles were prepared by combustion method using urea as a combustion fuel. The effects of calcination temperature, 350–1000 °C, on the physicochemical, surface and catalytic properties of the prepared Co{sub 3}O{sub 4} nano-particles were studied. The products were characterized by thermal analyses (TGA and DTA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques. Textural features of the obtained catalysts were investigated using nitrogen adsorption at −196 °C. X-ray diffraction confirmed that the resulting oxide was pure single-crystalline Co{sub 3}O{sub 4} nano-particles. Transmission electron microscopy indicating that, the crystallite size of Co{sub 3}O{sub 4} nano-crystals was in the range of 8–34 nm. The catalytic activities of prepared nano-crystalline Co{sub 3}O{sub 4} catalysts were tested for H{sub 2}O{sub 2} decomposition at 35–50 °C temperature range. Experimental results revealed that, the catalytic decomposition of H{sub 2}O{sub 2} decreases with increasing the calcination temperature. This was correlated with the observed particle size increase accompanying the calcination temperature rise.

Microwave-assisted rapid extracellular synthesis of stable bio-functionalized silver nanoparticles from guava ( Psidium guajava) leaf extract

Science.gov (United States)

Raghunandan, Deshpande; Mahesh, Bedre D.; Basavaraja, S.; Balaji, S. D.; Manjunath, S. Y.; Venkataraman, A.

2011-05-01

Our research interest centers on microwave-assisted rapid extracellular synthesis of bio-functionalized silver nanoparticles of 26 ± 5 nm from guava ( Psidium guajava) leaf extract with control over dimension and composition. The reaction occurs very rapidly as the formation of spherical nanoparticles almost completed within 90 s. The probable pathway of the biosynthesis is suggested. Appearance, crystalline nature, size and shape of nanoparticles are understood by UV-vis (UV-vis spectroscopy), FTIR (fourier transform infrared spectroscopy), XRD (X-ray diffraction), FESEM (field emission scanning electron microscopy) and TEM (transmission electron microscopy) techniques. Microwave-assisted route is selected for the synthesis of silver nanoparticles to carry out the reaction fast, suppress the enzymatic action and to keep the process environmentally clean and green.

Microwave-assisted rapid extracellular synthesis of stable bio-functionalized silver nanoparticles from guava (Psidium guajava) leaf extract

Energy Technology Data Exchange (ETDEWEB)

Raghunandan, Deshpande [H.K.E.S' s College of Pharmacy (India); Mahesh, Bedre D. [Gulbarga University, Materials Chemistry Laboratory, Department of Material Science (India); Basavaraja, S. [Jawaharlal Nehru Centre for Advanced Scientific Research, Veeco-India Nanotechnology Laboratory (India); Balaji, S. D. [Gulbarga University, Materials Chemistry Laboratory, Department of Material Science (India); Manjunath, S. Y. [Sri Krupa, Institute of Pharmaceutical Science (India); Venkataraman, A., E-mail: raman_chem@rediffmail.com [Gulbarga University, Materials Chemistry Laboratory, Department of Material Science (India)

2011-05-15

Our research interest centers on microwave-assisted rapid extracellular synthesis of bio-functionalized silver nanoparticles of 26 {+-} 5 nm from guava (Psidium guajava) leaf extract with control over dimension and composition. The reaction occurs very rapidly as the formation of spherical nanoparticles almost completed within 90 s. The probable pathway of the biosynthesis is suggested. Appearance, crystalline nature, size and shape of nanoparticles are understood by UV-vis (UV-vis spectroscopy), FTIR (fourier transform infrared spectroscopy), XRD (X-ray diffraction), FESEM (field emission scanning electron microscopy) and TEM (transmission electron microscopy) techniques. Microwave-assisted route is selected for the synthesis of silver nanoparticles to carry out the reaction fast, suppress the enzymatic action and to keep the process environmentally clean and green.

Microwave-assisted rapid extracellular synthesis of stable bio-functionalized silver nanoparticles from guava (Psidium guajava) leaf extract

International Nuclear Information System (INIS)

Raghunandan, Deshpande; Mahesh, Bedre D.; Basavaraja, S.; Balaji, S. D.; Manjunath, S. Y.; Venkataraman, A.

2011-01-01

Our research interest centers on microwave-assisted rapid extracellular synthesis of bio-functionalized silver nanoparticles of 26 ± 5 nm from guava (Psidium guajava) leaf extract with control over dimension and composition. The reaction occurs very rapidly as the formation of spherical nanoparticles almost completed within 90 s. The probable pathway of the biosynthesis is suggested. Appearance, crystalline nature, size and shape of nanoparticles are understood by UV–vis (UV–vis spectroscopy), FTIR (fourier transform infrared spectroscopy), XRD (X-ray diffraction), FESEM (field emission scanning electron microscopy) and TEM (transmission electron microscopy) techniques. Microwave-assisted route is selected for the synthesis of silver nanoparticles to carry out the reaction fast, suppress the enzymatic action and to keep the process environmentally clean and green.

Analysis of YBCO high temperature superconductor doped with silver nanoparticles and carbon nanotubes using Williamson-Hall and size-strain plot

Science.gov (United States)

Dadras, Sedigheh; Davoudiniya, Masoumeh

2018-05-01

This paper sets out to investigate and compare the effects of Ag nanoparticles and carbon nanotubes (CNTs) doping on the mechanical properties of Y1Ba2Cu3O7-δ (YBCO) high temperature superconductor. For this purpose, the pure and doped YBCO samples were synthesized by sol-gel method. The microstructural analysis of the samples is performed using X-ray diffraction (XRD). The crystalline size, lattice strain and stress of the pure and doped YBCO samples were estimated by modified forms of Williamson-Hall analysis (W-H), namely, uniform deformation model (UDM), uniform deformation stress model (UDSM) and the size-strain plot method (SSP). These results show that the crystalline size, lattice strain and stress of the YBCO samples declined by Ag nanoparticles and CNTs doping.

Polyol-mediated thermolysis process for the synthesis of MgO nanoparticles and nanowires

Energy Technology Data Exchange (ETDEWEB)

Subramania, A; Kumar, G Vijaya; Priya, A R Sathiya; Vasudevan, T [Advanced Materials Research Lab, Department of Industrial Chemistry, Alagappa University, Karaikudi-630 003 (India)

2007-06-06

The main aim of this work is to prepare MgO nanoparticles and nanowires by a novel polyol-mediated thermolysis (PMT) process. The influence of different mole concentration of magnesium acetate, polyvinyl pyrrolidone (PVP; capping agent) and ethylene glycol (EG; solvent as well as reducing agent) on the formation of nanoparticles and nanowires and the effect of calcination on the crystalline size of the samples were also examined. The resultant oxide structure, thermal behaviour, size and shape have been studied using x-ray diffraction (XRD) studies, thermal (TG/DTA) analysis and scanning electron microscopy (SEM)/transmission electron microscopy (TEM) respectively.

Polyol-mediated thermolysis process for the synthesis of MgO nanoparticles and nanowires

Science.gov (United States)

Subramania, A.; Vijaya Kumar, G.; Sathiya Priya, A. R.; Vasudevan, T.

2007-06-01

The main aim of this work is to prepare MgO nanoparticles and nanowires by a novel polyol-mediated thermolysis (PMT) process. The influence of different mole concentration of magnesium acetate, polyvinyl pyrrolidone (PVP; capping agent) and ethylene glycol (EG; solvent as well as reducing agent) on the formation of nanoparticles and nanowires and the effect of calcination on the crystalline size of the samples were also examined. The resultant oxide structure, thermal behaviour, size and shape have been studied using x-ray diffraction (XRD) studies, thermal (TG/DTA) analysis and scanning electron microscopy (SEM)/transmission electron microscopy (TEM) respectively.

Polyol-mediated thermolysis process for the synthesis of MgO nanoparticles and nanowires

International Nuclear Information System (INIS)

Subramania, A; Kumar, G Vijaya; Priya, A R Sathiya; Vasudevan, T

2007-01-01

The main aim of this work is to prepare MgO nanoparticles and nanowires by a novel polyol-mediated thermolysis (PMT) process. The influence of different mole concentration of magnesium acetate, polyvinyl pyrrolidone (PVP; capping agent) and ethylene glycol (EG; solvent as well as reducing agent) on the formation of nanoparticles and nanowires and the effect of calcination on the crystalline size of the samples were also examined. The resultant oxide structure, thermal behaviour, size and shape have been studied using x-ray diffraction (XRD) studies, thermal (TG/DTA) analysis and scanning electron microscopy (SEM)/transmission electron microscopy (TEM) respectively

Direct large-scale synthesis of perovskite barium strontium titanate nano-particles from solutions

International Nuclear Information System (INIS)

Qi Jianquan; Wang Yu; Wan Pingchen; Long Tuli; Chan, Helen Lai Wah

2005-01-01

This paper reports a wet chemical synthesis technique for large-scale fabrication of perovskite barium strontium titanate nano-particles near room temperature and under ambient pressure. The process employs titanium alkoxide and alkali earth hydroxides as starting materials and involves very simple operation steps. Particle size and crystallinity of the particles are controllable by changing the processing parameters. Observations by X-ray diffraction, scanning electron microscopy and transmission electron microscopy TEM indicate that the particles are well-crystallized, chemically stoichiometric and ∼50nm in diameter. The nanoparticles can be sintered into ceramics at 1150 deg. C and show typical ferroelectric hysteresis loops

Unexpected, spontaneous and selective formation of colloidal Pt 3Sn nanoparticles using organometallic Pt and Sn complexes

KAUST Repository

Boualleg, Malika; Baudouin, David; Basset, Jean-Marie; Bayard, Franç ois; Candy, Jean Pierre; Jumas, Jean Claude; Veyre, Laurent; Thieuleux, Chloé

2010-01-01

The facile and selective synthesis of small crystalline Pt3Sn alloy nanoparticles was performed at room temperature under H2, using a colloidal approach without the use of extra-stabilizing ligands. The Pt 3Sn alloy was found to be obtained

Influence of Fe nanoparticles diameters on the structure and electron emission studies of carbon nanotubes and multilayer graphene

International Nuclear Information System (INIS)

Sharma, Himani; Shukla, A.K.; Vankar, V.D.

2013-01-01

In this paper we report the effect of Fe film thickness on the growth, structure and electron emission characteristics of carbon nanotubes (CNTs) and multilayer graphene deposited on Si substrate. It is observed that the number of graphitic shells in carbon nanostructures (CNs) varies with the thickness of the catalyst depending on the average size of nanoparticles. Further, the Fe nanoparticles do not catalyze beyond a particular size of nanoclusters leading to the formation of multilayer graphene structure, instead of carbon nanotubes (CNTs). It is observed that the crystallinity of CNs enhances upon increasing the catalyst thickness. Multilayer graphene structures show improved crystallinity in comparison to CNTs as graphitic to defect mode intensity ratio (I D /I G ) decreases from 1.2 to 0.8. However, I 2D /I G value for multilayer graphene is found to be 1.1 confirming the presence of at least 10 layers of graphene in these samples. CNTs with smaller diameter show better electron emission properties with enhancement factor (γ C = 2.8 × 10 3 ) in comparison to multilayer graphene structure (γ C = 1.5 × 10 3 ). The better emission characteristics in CNTs are explained due to combination of electrons from edges as well as centers in comparison to the multilayer graphene. Highlights: ► Graphitic shells in CNTs and graphene depend on the size of Fe nanoparticles. ► The diameter of nanoparticles decides the morphology of CNTs and graphene. ► Multilayer graphene structures show improved crystallinity in comparison to CNTs. ► Multilayer graphene (MLG) has the γ C factor of 1.5 × 10 3 and CNTs has 2.8 × 10 3 . ► The nonlinearity in MLG may occur through change in work function.

Effect of gamma irradiation on the structural and magnetic properties of Co–Zn spinel ferrite nanoparticles

International Nuclear Information System (INIS)

Raut, Anil V.; Kurmude, D.V.; Shengule, D.R.; Jadhav, K.M.

2015-01-01

Highlights: • Co–Zn ferrite nanoparticles were examined before and after γ-irradiation. • Single phase cubic spinel structure of Co–Zn was confirmed by XRD data. • The grain size was reported in the range of 52–62 nm after γ-irradiation. • Ms, Hc, n B were reported to be increased after gamma irradiation. - Abstract: In this work, the structural and magnetic properties of Co 1−x Zn x Fe 2 O 4 (0.0 ≤ x ≤ 1.0) ferrite nanoparticles were studied before and after gamma irradiation. The as-synthesized samples of Co–Zn ferrite nanoparticles prepared by sol–gel auto-combustion technique were analysed by XRD which suggested the single phase; cubic spinel structure of the material. Crystal defects produced in the spinel lattice were studied before and after Co 60 γ-irradiation in a gamma cell with a dose rate of 0.1 Mrad/h in order to report the changes in structural and magnetic properties of the Co–Zn ferrite nanoparticles. The average crystallite size (t), lattice parameter (α) and other structural parameters of gamma-irradiated and un-irradiated Co 1−x Zn x Fe 2 O 4 spinel ferrite system was calculated from XRD data. The morphological characterizations were performed using scanning electron microscopy (SEM). The magnetic properties were measured using pulse field hysteresis loop tracer by applying magnetic field of 1000 Oe, and the analysis of data obtained revealed that the magnetic property such as saturation magnetization (Ms), coecivity (Hc), magneton number (n B ) etc. magnetic parameters were increased after irradiation

CdSe nanoparticles grown via radiolytic methods in aqueous solutions

Energy Technology Data Exchange (ETDEWEB)

Singh, Shalini [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Rath, M.C., E-mail: madhab@barc.gov.i [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Singh, A.K. [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Mukherjee, T. [Chemistry Group, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Jayakumar, O.D.; Tyagi, A.K. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Sarkar, S.K. [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

2011-06-15

Cadmium selenide, CdSe, nanoparticles have been synthesized in aqueous solution containing equimolar ammoniated CdSO{sub 4} and Na{sub 2}SeSO{sub 3} as the starting materials without any capping agents, using gamma and electron beam irradiation under a reducing condition. The radiolytic processes occurring in water result in the formation of CdSe nanoparticles through the reactions mediated by hydrated electrons, e{sub aq}{sup -}. TEM measurements revealed that the CdSe nanoparticles were found to exist in agglomerates of dimension of about 100 nm, consisting of primary nanoparticles of dimensions within 5 nm. The as-grown nanoparticles were of cubic crystalline phase as supported by the XRD measurements. These bare CdSe nanoparticles exhibit room temperature ferromagnetic (RTFM) behavior. However, the RTFM behavior was found to be 30% higher in the case of CdSe nanoparticles prepared on electron beam irradiation as compared to those obtained by gamma irradiation, which was attributed to their relatively smaller size (2-3 nm) and disordered structures as compared to those obtained in the later case (3-5 nm). -- Research highlights: {yields} CdSe nanoparticles could be synthesized in aqueous solutions containing equimolar ammoniated CdSO{sub 4} and Na{sub 2}SeSO{sub 3} as the starting materials using gamma and electron beam irradiation under a reducing condition. {yields} CdSe nanoparticles were found to exist in agglomerates of dimension of about 100 nm, consisting of primary nanoparticles of dimensions within 5 nm. {yields} CdSe nanoparticles exhibit room temperature ferromagnetic (RTFM) behavior. {yields} The RTFM behavior was found to be 30% higher in the case of CdSe nanoparticles prepared on electron beam irradiation as compared to those obtained by gamma irradiation.

One-step green synthesis and characterization of leaf extract-mediated biocompatible silver and gold nanoparticles from Memecylon umbellatum

Science.gov (United States)

Arunachalam, Kantha D; Annamalai, Sathesh Kumar; Hari, Shanmugasundaram

2013-01-01

In this experiment, green-synthesized silver and gold nanoparticles were produced rapidly by treating silver and gold ions with an extract of Memecylon umbellatum leaf. The reaction process was simple and easy to handle, and was monitored using ultraviolet-visible spectroscopy. The effect of the phytochemicals present in M. umbellatum, including saponins, phenolic compounds, phytosterols, and quinones, on formation of stable silver and gold nanoparticles was investigated by Fourier-transform infrared spectroscopy. The morphology and crystalline phase of the nanoparticles were determined by transmission electron microscopy and energy-dispersive x-ray spectroscopy. The results indicate that the saponins, phytosterols, and phenolic compounds present in the plant extract play a major role in formation of silver and gold nanoparticles in their respective ions in solution. The characteristics of the nanoparticles formed suggest application of silver and gold nanoparticles as chemical sensors in the future. Given the simple and eco-friendly approach for synthesis, these nanoparticles could easily be commercialized for large-scale production. PMID:23569372

Structural and magnetic properties of cobalt-doped iron oxide nanoparticles prepared by solution combustion method for biomedical applications.

Science.gov (United States)

Venkatesan, Kaliyamoorthy; Rajan Babu, Dhanakotti; Kavya Bai, Mane Prabhu; Supriya, Ravi; Vidya, Radhakrishnan; Madeswaran, Saminathan; Anandan, Pandurangan; Arivanandhan, Mukannan; Hayakawa, Yasuhiro

2015-01-01

Cobalt-doped iron oxide nanoparticles were prepared by solution combustion technique. The structural and magnetic properties of the prepared samples were also investigated. The average crystallite size of cobalt ferrite (CoFe2O4) magnetic nanoparticle was calculated using Scherrer equation, and it was found to be 16±5 nm. The particle size was measured by transmission electron microscope. This value was found to match with the crystallite size calculated by Scherrer equation corresponding to the prominent intensity peak (311) of X-ray diffraction. The high-resolution transmission electron microscope image shows clear lattice fringes and high crystallinity of cobalt ferrite magnetic nanoparticles. The synthesized magnetic nanoparticles exhibited the saturation magnetization value of 47 emu/g and coercivity of 947 Oe. The anti-microbial activity of cobalt ferrite nanoparticles showed better results as an anti-bacterial agent. The affinity constant was determined for the nanoparticles, and the cytotoxicity studies were conducted for the cobalt ferrite nanoparticles at different concentrations and the results are discussed.

Discrepancy between different estimates of the hydrodynamic diameter of polymer-coated iron oxide nanoparticles in solution

International Nuclear Information System (INIS)

Regmi, R.; Gumber, V.; Subba Rao, V.; Kohli, I.; Black, C.; Sudakar, C.; Vaishnava, P.; Naik, V.; Naik, R.; Mukhopadhyay, A.; Lawes, G.

2011-01-01

We have synthesized iron oxide nanoparticles coated with a monolayer of dextran, with molecular weights of the polymer between 5 and 670 kDa. Transmission electron microscopy images confirm that the hard core has a crystalline diameter of approximately 12 nm. The hydrodynamic diameters of these coated nanoparticles in solution measured using dynamical light scattering and estimated from magnetic susceptibility studies vary from near 90 nm for the lightest polymer to 140 nm for the heaviest polymer. Conversely, fluorescence correlation spectroscopy measurements yield a diameter of approximately 55 nm for the 15–20 kDa dextran coated nanoparticles, which is consistent with the expected value estimated from the sum of the hard-core diameter and monolayer dextran coating. We discuss the implications of this discrepancy for applications involving polymer-coated magnetic nanoparticles.

Induction heating studies of combustion synthesized MgFe2O4 nanoparticles for hyperthermia applications

International Nuclear Information System (INIS)

Khot, V.M.; Salunkhe, A.B.; Thorat, N.D.; Phadatare, M.R.; Pawar, S.H.

2013-01-01

The structural, magnetic and ac magnetically induced heating characteristics of combustion synthesized MgFe 2 O 4 nanoparticles have been investigated for application in magnetic particle hyperthermia. As prepared nanoparticles showed ferrimagnetic behavior at room temperature with magnetization of about 33.83 emu/g at ±15 kOe. The solid state MgFe 2 O 4 nanoparticles exhibited specific absorption rate (SAR) of about 297 W/g at physiological safe range of frequency and amplitude. The increase in SAR and heating temperature in ac magnetic field was thought to be due to enhancement in magnetic hysteresis loss caused by dipole–dipole interactions in combustion synthesized MgFe 2 O 4 nanoparticles. - Highlights: ► Highly crystalline pure MgFe 2 O 4 nanoparticles were synthesized by low temperature combustion. ► Effect of ac magnetic field and nanoparticles concentration on heating characteristics of MgFe 2 O 4 nanoparticles was studied. ► Combustion synthesized MgFe 2 O 4 nanoparticles show highest specific absorption rate of 297 Wg −1 . ► The reported high value of specific absorption rate is advantageous for its use in magnetic particle hyperthermia

Structural investigations on differently sized monodisperse iron oxide nanoparticles synthesized by remineralization of apoferritin molecules

International Nuclear Information System (INIS)

Ullrich, Aladin; Horn, Siegfried

2013-01-01

We have investigated the structure of iron oxide nanoparticles produced by remineralization and thermal treatment of horse spleen apoferritin molecules. The described procedure allows to synthesize particles with diameters ranging from 4 to 7 nm in size. Atomic force microscopy and transmission electron microscopy (TEM) investigations were performed for shape and size determination, whereas energy-dispersive X-ray (TEM-EDX), high-resolution TEM, and electron diffraction measurements revealed the chemical composition and crystal structure of the particles. We found predominantly single crystalline nanoparticles with a hematite-like (α-Fe 2 O 3 ) structure

Synthesis and characterization of Er3+ doped CaF2 nanoparticles

International Nuclear Information System (INIS)

Zhi Guanglin; Song Jinghong; Mei Bingchu; Zhou Weibing

2011-01-01

Highlights: → Er 3+ :CaF 2 nanoparticles were synthesized by co-precipitation method with particle size of 8-36 nm. → Increasing dopant concentration increases lattice constants and decreases grain size. → Annealing treatment has a remarkable effect on luminescence properties. → Luminescence intensity decrease with the increasing of the dopant concentration. - Abstract: Er 3+ doped CaF 2 nanoparticles were synthesized by a chemical co-precipitation method. Effect of the dopant concentrations on the structure and optical properties of the CaF 2 nanoparticles was investigated. The X-ray powder diffraction and transmission electron microscopy analysis was used to characterize the structure and morphology of the nanoparticles. The nanoparticles with different dopant concentration exhibited a sphere-like morphology with diameters of about 8-36 nm. The incorporation of Er 3+ ions into CaF 2 resulted in the decrease in grain size and deterioration of crystallinity, but enlarged the lattice constants of CaF 2 . Additional annealing treatment at 400 deg. C to the prepared CaF 2 removed the NO 3 - and OH - groups adsorbed on the particles' surfaces, and improved the optical properties of the nanoparticles. The fluorescence intensity, with a maximum at approximately 0.4 mol%, decreased with the increase in doping concentration because of concentration quenching.

Dissolution enhancement of curcumin via curcumin-prebiotic inulin nanoparticles.

Science.gov (United States)

Fares, Mohammad M; Salem, Mu'taz Sheikh

2015-01-01

Dissolution enhancement of curcumin via prebiotic inulin designed to orally deliver poorly water-soluble curcumin at duodenum low acidity (pH 5.5) was investigated. Different prebiotic inulin-curcumin nanoparticles were synthesized in ethanol-water binary system at different pre-adjusted pH values. Characterization via FTIR, XRD and TGA revealed the formation of curcumin-inulin conjugates, whereas surface morphology via SEM and TEM techniques implied the formation of nanoparticle beads and nanoclusters. Prebiotic inulin-curcumin nanoparticles prepared at pH 7.0 demonstrated a maximum curcumin dissolution enhancement of ≈90% with respect to 30% for curcumin alone at pH 5.5. Power law constant values were in accordance with dissolution enhancement investigations. All samples show Fickian diffusion mechanism. XRD investigations confirm that inulin maintain its crystalline structure in curcumin-inulin conjugate structure, which confirms that it can exert successfully its prebiotic role in the gastrointestinal (GI) tract. Therefore, the use of curcumin-inulin nanoparticles can perform dual-mission in the GI tract at the duodenum environment; release of 90% of curcumin followed by prebiotic activity of inulin, which will probably play a significant role in cancer therapeutics for the coming generations.

Characterization of Corn Starch Films Reinforced with CaCO3 Nanoparticles

Science.gov (United States)

Sun, Qingjie; Xi, Tingting; Li, Ying; Xiong, Liu

2014-01-01

The characterization of corn starch (CS) films impregnated with CaCO3 nanoparticles was investigated. Criteria such as morphology, crystallinity, water vapor permeability (WVP), opacity, and mechanical properties were the focus of the investigation. It was found that the CaCO3 contents had significant effects on the tensile properties of the nanocomposite films. The addition of CaCO3 nanoparticles to the CS films significantly increased tensile strength from 1.40 to 2.24 MPa, elongation from 79.21 to 118.98%, and Young’s modulus from 1.82 to 2.41 MPa. The incorporation of CaCO3 nanoparticles increased the opacity of films, lowered the degree of WVP and film solubility value compared to those of the CS films. The results of scanning electron microscopy (SEM) showed that with the increase of CaCO3 nanoparticles content in starch films, the roughness of the films increased, and pores or cavities were found on the surface of the films, while small cracks were observed in the structures of the fractured surfaces. X-ray diffraction showed that the addition of nanoparticles increased the peaks in the intensity of films. PMID:25188503

Gram-scale synthesis of highly crystalline, 0-D and 1-D SnO2 nanostructures through surfactant-free hydrothermal process

International Nuclear Information System (INIS)

Pal, Umapada; Pal, Mou; Sánchez Zeferino, Raul

2012-01-01

We report the synthesis of highly crystalline SnO 2 nanoparticle and nanorod structures with average diameters well within quantum confinement limit (3.5−6.4 nm), through surfactant-free hydrothermal synthesis. The size and shape of the nanostructures could be controlled by controlling the pH (4.5–13.0) of the reaction mixture and the temperature of hydrothermal treatment. Probable mechanisms for the variation of particle size and growth of one-dimensional structures are presented considering the size-dependent crystal solubility at lower pH values of the reaction solution and Ostwald ripening of the quasi-spherical nanoparticles at higher pH values, respectively. Variation of optical band gap energy and hence the effects of quantum confinement in the nanostructures have been studied.

Interaction of fibrinogen and albumin with titanium dioxide nanoparticles of different crystalline phases

International Nuclear Information System (INIS)

Marucco, Arianna; Fenoglio, Ivana; Turci, Francesco; Fubini, Bice

2013-01-01

TiO 2 nanoparticles (NPs) are contained in different kinds of industrial products including paints, self-cleaning glasses, sunscreens. TiO 2 is also employed in photocatalysis and it has been proposed for waste water treatment. Micrometric TiO 2 is generally considered a safe material, while there is concern on the possible health effects of nanometric titania. Due to their small size NPs may migrate within the human body possibly entering in the blood stream. Therefore studies on the interaction of NPs with plasma proteins are needed. In fact, the interaction with proteins is believed to ultimately influences the NPs biological fate. Fibrinogen and albumin are two of the most abundant plasma proteins. They are involved in several important physiological functions. Furthermore, fibrinogen is known to trigger platelet adhesion and inflammation. For these reasons the study of the interaction between these protein and nanoparticles is an important step toward the understanding of the behavior of NPs in the body. In this study we investigated the interaction of albumin and fibrinogen with TiO 2 nanoparticles of different crystal phases (rutile and anatase) using an integrated set of techniques. The amount of adsorbed fibrinogen and albumin for each TiO 2 surface was investigated by using the bicinchoninic acid assay (BCA). The variation of the surface charge of the NP-protein conjugates respect to the naked NPs was used to indirectly estimate both surface coverage and reversibility of the adsorption upon dilution. Surface charge was monitored by measuring the ζ potential with a conventional electrophoretic light scattering (ELS) system. The extent of protein deformation was evaluated by Raman Spectroscopy. We found that both proteins adsorb irreversibly against electrostatic repulsion, likely undergoing conformational changes or selective orientation upon adsorption. The size of primary particles and the particles aggregation rather than the crystal phase modulate the

DNA-nanoparticle superlattices formed from anisotropic building blocks

Science.gov (United States)

Jones, Matthew R.; Macfarlane, Robert J.; Lee, Byeongdu; Zhang, Jian; Young, Kaylie L.; Senesi, Andrew J.; Mirkin, Chad A.

2010-11-01

Directional bonding interactions in solid-state atomic lattices dictate the unique symmetries of atomic crystals, resulting in a diverse and complex assortment of three-dimensional structures that exhibit a wide variety of material properties. Methods to create analogous nanoparticle superlattices are beginning to be realized, but the concept of anisotropy is still largely underdeveloped in most particle assembly schemes. Some examples provide interesting methods to take advantage of anisotropic effects, but most are able to make only small clusters or lattices that are limited in crystallinity and especially in lattice parameter programmability. Anisotropic nanoparticles can be used to impart directional bonding interactions on the nanoscale, both through face-selective functionalization of the particle with recognition elements to introduce the concept of valency, and through anisotropic interactions resulting from particle shape. In this work, we examine the concept of inherent shape-directed crystallization in the context of DNA-mediated nanoparticle assembly. Importantly, we show how the anisotropy of these particles can be used to synthesize one-, two- and three-dimensional structures that cannot be made through the assembly of spherical particles.

Green synthesis of monodisperse silver nanoparticles using hydroxy propyl methyl cellulose

Energy Technology Data Exchange (ETDEWEB)

Dong, Chunfa; Zhang, Xianglin, E-mail: hust_zxl@mail.hust.edu.cn; Cai, Hao

2014-01-15

Graphical abstract: -- Highlights: • Synthesis of silver nanoparticles using hydroxy propyl methyl cellulose is reported. • HPMC and glucose are used as capping agent and reducing agent respectively. • It is the first time to use HPMC for synthesis of silver nanoparticles. • The small, spherical and well-dispersed particle is observed in the range of 3–17 nm. • The green method can be extended to other noble metals. -- Abstract: A simple and environmentally friendly method for the synthesis of highly stable and small sized silver nanoparticles with narrow distribution from 3 nm to 17 nm is reported. Silver nitrate, hydroxy propyl methyl cellulose (HPMC) and glucose, were used as silver precursor, capping agents and reducing agents respectively. The formation of silver nanoparticles was observed by change of color from colorless to wine red. The silver nanoparticles were characterized by transmission electron microscopy (TEM), UV–visible spectroscopy (UV–vis), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR). The results demonstrated that the obtained metallic nanoparticles were single crystalline silver nanoparticles capped with HPMC. The effects of the reaction time, reaction temperature and the concentration of silver ion and reducing agents on the particle size were investigated. A possible formation mechanism was proposed. The method may be extended to other noble metal for other technological applications such as additional medicinal, industrial applications.

Green synthesis of monodisperse silver nanoparticles using hydroxy propyl methyl cellulose

International Nuclear Information System (INIS)

Dong, Chunfa; Zhang, Xianglin; Cai, Hao

2014-01-01

Graphical abstract: -- Highlights: • Synthesis of silver nanoparticles using hydroxy propyl methyl cellulose is reported. • HPMC and glucose are used as capping agent and reducing agent respectively. • It is the first time to use HPMC for synthesis of silver nanoparticles. • The small, spherical and well-dispersed particle is observed in the range of 3–17 nm. • The green method can be extended to other noble metals. -- Abstract: A simple and environmentally friendly method for the synthesis of highly stable and small sized silver nanoparticles with narrow distribution from 3 nm to 17 nm is reported. Silver nitrate, hydroxy propyl methyl cellulose (HPMC) and glucose, were used as silver precursor, capping agents and reducing agents respectively. The formation of silver nanoparticles was observed by change of color from colorless to wine red. The silver nanoparticles were characterized by transmission electron microscopy (TEM), UV–visible spectroscopy (UV–vis), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR). The results demonstrated that the obtained metallic nanoparticles were single crystalline silver nanoparticles capped with HPMC. The effects of the reaction time, reaction temperature and the concentration of silver ion and reducing agents on the particle size were investigated. A possible formation mechanism was proposed. The method may be extended to other noble metal for other technological applications such as additional medicinal, industrial applications

Green synthesis of soya bean sprouts-mediated superparamagnetic Fe3O4 nanoparticles

International Nuclear Information System (INIS)

Cai Yan; Shen Yuhua; Xie Anjian; Li Shikuo; Wang Xiufang

2010-01-01

Superparamagnetic Fe 3 O 4 nanoparticles were first synthesized via soya bean sprouts (SBS) templates under ambient temperature and normal atmosphere. The reaction process was simple, eco-friendly, and convenient to handle. The morphology and crystalline phase of the nanoparticles were determined from scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and X-ray diffraction (XRD) spectra. The effect of SBS template on the formation of Fe 3 O 4 nanoparticles was investigated using X-ray photoemission spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FT-IR). The results indicate that spherical Fe 3 O 4 nanoparticles with an average diameter of 8 nm simultaneously formed on the epidermal surface and the interior stem wall of SBS. The SBS are responsible for size and morphology control during the whole formation of Fe 3 O 4 nanoparticles. In addition, the superconducting quantum interference device (SQUID) results indicate the products are superparamagnetic at room temperature, with blocking temperature (T B ) of 150 K and saturation magnetization of 37.1 emu/g.

Green synthesis of soya bean sprouts-mediated superparamagnetic Fe 3O 4 nanoparticles

Science.gov (United States)

Cai, Yan; Shen, Yuhua; Xie, Anjian; Li, Shikuo; Wang, Xiufang

2010-10-01

Superparamagnetic Fe 3O 4 nanoparticles were first synthesized via soya bean sprouts (SBS) templates under ambient temperature and normal atmosphere. The reaction process was simple, eco-friendly, and convenient to handle. The morphology and crystalline phase of the nanoparticles were determined from scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and X-ray diffraction (XRD) spectra. The effect of SBS template on the formation of Fe 3O 4 nanoparticles was investigated using X-ray photoemission spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FT-IR). The results indicate that spherical Fe 3O 4 nanoparticles with an average diameter of 8 nm simultaneously formed on the epidermal surface and the interior stem wall of SBS. The SBS are responsible for size and morphology control during the whole formation of Fe 3O 4 nanoparticles. In addition, the superconducting quantum interference device (SQUID) results indicate the products are superparamagnetic at room temperature, with blocking temperature ( TB) of 150 K and saturation magnetization of 37.1 emu/g.

Multiscale study of metal nanoparticles

Science.gov (United States)

Lee, Byeongchan

Extremely small structures with reduced dimensionality have emerged as a scientific motif for their interesting properties. In particular, metal nanoparticles have been identified as a fundamental material in many catalytic activities; as a consequence, a better understanding of structure-function relationship of nanoparticles has become crucial. The functional analysis of nanoparticles, reactivity for example, requires an accurate method at the electronic structure level, whereas the structural analysis to find energetically stable local minima is beyond the scope of quantum mechanical methods as the computational cost becomes prohibitingly high. The challenge is that the inherent length scale and accuracy associated with any single method hardly covers the broad scale range spanned by both structural and functional analyses. In order to address this, and effectively explore the energetics and reactivity of metal nanoparticles, a hierarchical multiscale modeling is developed, where methodologies of different length scales, i.e. first principles density functional theory, atomistic calculations, and continuum modeling, are utilized in a sequential fashion. This work has focused on identifying the essential information that bridges two different methods so that a successive use of different methods is seamless. The bond characteristics of low coordination systems have been obtained with first principles calculations, and incorporated into the atomistic simulation. This also rectifies the deficiency of conventional interatomic potentials fitted to bulk properties, and improves the accuracy of atomistic calculations for nanoparticles. For the systematic shape selection of nanoparticles, we have improved the Wulff-type construction using a semi-continuum approach, in which atomistic surface energetics and crystallinity of materials are added on to the continuum framework. The developed multiscale modeling scheme is applied to the rational design of platinum

Green Biosynthesis of Silver Nanoparticles Using Callicarpa maingayi Stem Bark Extraction

Directory of Open Access Journals (Sweden)

Mohammed Zidan

2012-07-01

Full Text Available Different biological methods are gaining recognition for the production of silver nanoparticles (Ag-NPs due to their multiple applications. The use of plants in the green synthesis of nanoparticles emerges as a cost effective and eco-friendly approach. In this study the green biosynthesis of silver nanoparticles using Callicarpa maingayi stem bark extract has been reported. Characterizations of nanoparticles were done using different methods, which include; ultraviolet-visible spectroscopy (UV-Vis, powder X-ray diffraction (XRD, transmission electron microscopy (TEM, scanning electron microscopy (SEM, energy dispersive X-ray fluorescence (EDXF spectrometry, zeta potential measurements and Fourier transform infrared (FT-IR spectroscopy. UV-visible spectrum of the aqueous medium containing silver nanoparticles showed absorption peak at around 456 nm. The TEM study showed that mean diameter and standard deviation for the formation of silver nanoparticles were 12.40 ± 3.27 nm. The XRD study showed that the particles are crystalline in nature, with a face centered cubic (fcc structure. The most needed outcome of this work will be the development of value added products from Callicarpa maingayi for biomedical and nanotechnology based industries.

Green synthesis of Silver and Gold Nanoparticles for Enhanced catalytic and bactericidal activity

Science.gov (United States)

Naraginti, S.; Tiwari, N.; Sivakumar, A.

2017-11-01

A rapid one step green synthetic method using kiwi fruit extract was employed for preparation of silver and gold nanoparticles. The synthesized nanoparticles were successfully used as green catalysts for the reduction of 4-nitrophenol (4-NP) and methylene blue (MB). They also exhibited excellent antimicrobial activity against clinically isolated Pseudomonas aeruginosa (P.aeruginosa) and Staphylococcus aureus (S.aureus). It was noticed that with increase in concentration of the aqueous silver and gold solutions, particle size of the Ag and Au NPS showed increase as evidenced from UV-Visible spectroscopy and TEM micrograph. The method employed for the synthesis required only a few minutes for more than 90% formation of nanoparticles when the temperature was raised to 80°C. It was also noticed that the catalytic activity of nanoparticles depends upon the size of the particles. These nanoparticles were observed to be crystalline from the clear lattice fringes in the transmission electron microscopic (TEM) images, bright circular spots in the selected area electron diffraction (SAED) pattern and peaks in the X-ray diffraction (XRD) pattern. The Fourier-transform infrared (FTIR) spectrum indicated the presence of different functional groups in the biomolecule capping the nanoparticles.

Trichoderma koningii assisted biogenic synthesis of silver nanoparticles and evaluation of their antibacterial activity

Science.gov (United States)

Tripathi, R. M.; Gupta, Rohit Kumar; Shrivastav, Archana; Singh, M. P.; Shrivastav, B. R.; Singh, Priti

2013-09-01

The present study demonstrates the biosynthesis of silver nanoparticles using Trichoderma koningii and evaluation of their antibacterial activity. Trichoderma koningii secretes proteins and enzymes that act as reducing and capping agent. The biosynthesized silver nanoparticles (AgNPs) were characterized by UV-Vis spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM) and x-ray diffraction (XRD). UV-Vis spectra showed absorbance peak at 413 nm corresponding to the surface plasmon resonance of silver nanoparticles. DLS was used to find out the size distribution profile. The size and morphology of the AgNPs was determined by TEM, which shows the formation of spherical nanoparticles in the size range of 8-24 nm. X-ray diffraction showed intense peaks corresponding to the crystalline silver. The antibacterial activity of biosynthesized AgNPs was evaluated by growth curve and inhibition zone and it was found that the AgNPs show potential effective antibacterial activity.

The synthesis and characterization of polymer-coated FeAu multifunctional nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Liu Hongling; Hou Peng; Zhang Wengxing [Institute of Molecular and Crystal Engineering, School of Chemistry and Chemical Engineering, Henan University, Kaifeng 475001, Henan (China); Kim, Young Keun [Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Wu Junhua, E-mail: feitianshenhu@yahoo.com [Research Institute of Engineering and Technology, Korea University, Seoul 136-713 (Korea, Republic of)

2010-08-20

We report the one-pot nanoemulsion synthesis of FeAu magnetic-optical multifunctional nanoparticles coated by the biocompatible triblock copolymer, poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEO-PPO-PEO). The FTIR study confirms the PEO-PPO-PEO molecules on the surface of the resulting nanoparticles. The structural characterization identifies the crystallographic parameter 4.072 A of the cubic phase and the morphology analysis gives the nanoparticle shape, size and size distribution, showing the high crystallinity of the FeAu nanoparticles and an average particle size of {approx} 6.5 nm. In addition there is direct confirmation of the alloying by elemental point probing of an individual nanoparticle. Following the visual demonstration of a rapid, efficient and reversible dispersion-collection process of the nanoparticles in solution, the magnetic measurement manifests a soft ferromagnetic behavior of the nanoparticles with a small coercivity of {approx} 60 Oe at room temperature. The corresponding magnetic hysteresis curves were effectively assessed by modified bi-phase Langevin equations, which were satisfactorily explained in terms of a bimodal particle size distribution. The UV-vis studies display the broadband absorption of the PEO-PPO-PEO-coated nanoparticles with the maximum surface plasmon resonance around 585 nm. The characterization and analysis, therefore, shows the unification of iron and gold into one alloy nanostructure entity covered by the biocompatible triblock copolymer thin film, preserving the optical and magnetic properties of the individual constituents. This gives the prospect of enhanced performance in applications.

The synthesis and characterization of polymer-coated FeAu multifunctional nanoparticles

International Nuclear Information System (INIS)

Liu Hongling; Hou Peng; Zhang Wengxing; Kim, Young Keun; Wu Junhua

2010-01-01

We report the one-pot nanoemulsion synthesis of FeAu magnetic-optical multifunctional nanoparticles coated by the biocompatible triblock copolymer, poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEO-PPO-PEO). The FTIR study confirms the PEO-PPO-PEO molecules on the surface of the resulting nanoparticles. The structural characterization identifies the crystallographic parameter 4.072 A of the cubic phase and the morphology analysis gives the nanoparticle shape, size and size distribution, showing the high crystallinity of the FeAu nanoparticles and an average particle size of ∼ 6.5 nm. In addition there is direct confirmation of the alloying by elemental point probing of an individual nanoparticle. Following the visual demonstration of a rapid, efficient and reversible dispersion-collection process of the nanoparticles in solution, the magnetic measurement manifests a soft ferromagnetic behavior of the nanoparticles with a small coercivity of ∼ 60 Oe at room temperature. The corresponding magnetic hysteresis curves were effectively assessed by modified bi-phase Langevin equations, which were satisfactorily explained in terms of a bimodal particle size distribution. The UV-vis studies display the broadband absorption of the PEO-PPO-PEO-coated nanoparticles with the maximum surface plasmon resonance around 585 nm. The characterization and analysis, therefore, shows the unification of iron and gold into one alloy nanostructure entity covered by the biocompatible triblock copolymer thin film, preserving the optical and magnetic properties of the individual constituents. This gives the prospect of enhanced performance in applications.

Facile synthesis of palladium nanoparticle doped polyaniline nanowires in soft templates for catalytic applications

Science.gov (United States)

Kshirasagar, Krushna J.; Markad, Uddhav S.; Saha, Abhijit; Sharma, Kiran Kumar K.; Sharma, Geeta K.

2017-02-01

Palladium nanoparticles doped polyaniline (Pd-PANI) nanocomposite (NCs) is synthesized in surfactant based liquid crystalline mesophase by chemical oxidation followed by radiolysis. The confinement of the liquid crystalline mesophase facilitates polymerization of aniline monomers and their 1D growth into polyaniline (PANI) nanowires by using ammonium persulfate. The PANI nanowires have an average diameter of 30-40 nm. The in situ radiolytic reduction of palladium ions ensures uniform size distribution of the palladium (Pd) nanoparticles on the surface of the PANI nanowires. The synthesized Pd-PANI nanocomposites show wire like structures of PANI (diameter ~30-40 nm) on which Pd nanoparticles of the size 10 nm are decorated. The identical average diameter of the PANI nanowires before and post gamma irradiation suggest high stability of the PANI nanowires in liquid crystalline mesophase. Surface characterization of the NCs were carried out using BET and XPS. The catalytic activity of Pd-PANI NCs are investigated in the reduction of methylene blue (MB) and 4-nitro phenol (4-NP) by sodium borohydride (NaBH4). The kinetics of the Pd-PANI NCs catalysed reactions are analysed using the Langmuir-Hinshelwood model. The apparent rate constant (k app) for the MB and 4-NP reduction reactions is 29  ×  10-3 s-1 and 20  ×  10-3 s-1 respectively with an actual Pd catalyst loading of 2.665  ×  10-4 ppm. Further, the recyclability of the Pd-PANI NCs catalyst in both the reduction reactions shows the stability of the catalyst up to four reaction cycles tested in this investigation and the multifunctional nature of the catalyst. The study provides a new approach for the directional synthesis of conducting polymer-metal nanocomposites and their possible application as a nanocatalyst in environmental remediation.

Interference between nanoparticles and metal homeostasis

International Nuclear Information System (INIS)

Petit, A N; Catty, P; Charbonnier, P; Cuillel, M; Mintz, E; Moulis, J M; Niviere, V; Choudens, S Ollagnier de; Garcia, C Aude; Candeias, S; Chevallet, M; Collin-Faure, V; Lelong, C; Luche, S; Rabilloud, T; Casanova, A; Herlin-Boime, N; Douki, T; Ravanat, J L; Sauvaigo, S

2011-01-01

The TiO 2 nanoparticles (NPs) are now produced abundantly and widely used in a variety of consumer products. Due to the important increase in the production of TiO 2 -NPs, potential widespread exposure of humans and environment may occur during both the manufacturing process and final use. Therefore, the potential toxicity of TiO 2 -NPs on human health and environment has attracted particular attention. Unfortunately, the results of the large number of studies on the toxicity of TiO 2 -NPs differ significantly, mainly due to an incomplete characterization of the used nanomaterials in terms of size, shape and crystalline structure and to their unknown state of agglomeration/aggregation. The purpose of our project entitled NanoBioMet is to investigate if interferences between nanoparticles and metal homeostasis could be observed and to study the toxicity mechanisms of TiO 2 -NPs with well-characterized physicochemical parameters, using proteomic and molecular approaches. A perturbation of metal homeostasis will be evaluated upon TiO 2 -NPs exposure which could generate reactive oxygen species (ROS) production. Moreover, oxidative stress consequences such as DNA damage and lipid peroxidation will be studied. The toxicity of TiO 2 -NPs of different sizes and crystalline structures will be evaluated both in prokaryotic (E. coli) and eukaryotic cells (A549 human pneumocytes, macrophages, and hepatocytes). First results of the project will be presented concerning the dispersion of TiO 2 -NPs in bacterial medium, proteomic studies on total extracts of macrophages and genotoxicity on pneumocytes.

Structural, Optical, Morphological and Microbial Studies on SnO₂ Nanoparticles Prepared by Co-Precipitation Method.

Science.gov (United States)

Arularasu, M V; Anbarasu, M; Poovaragan, S; Sundaram, R; Kanimozhi, K; Magdalane, C Maria; Kaviyarasu, K; Thema, F T; Letsholathebe, D; Mola, Genene T; Maaza, M

2018-05-01

Nanoparticles of tin oxide (SnO2) powders were prepared by co-precipitation method at 500 °C, 700 °C and 900 °C temperature. The sintered SnO2 nanoparticles, structural, optical, magnetic, morphological properties and microbial activity have been studied. XRD studies reveals that sintered powder which exhibits tetragonal crystal structure and both crystallinity as well as crystal size increase with increase in temperature. The morphological studies reveal randomly arranged grains with compact nature grain size increases with sintering temperature. The compositional analyses of SnO2 nanoparticles have been studied using X-ray photoelectron spectroscopy analysis. The optical band gap values of SnO2 nanoparticles were calculated to be about 4.3 eV in the temperature 500 °C, comparing with that of the bulk SnO2 3.78 eV, by optical absorption measurement. Room temperature M-H curve for pure SnO2 nanoparticles exhibits ferromagnetic behaviour. The tin oxide nanoparticles are acted as potential candidate material for bacterial and fungal activity.

Photocatalytic activity of Ag3PO4 nanoparticle/TiO2 nanobelt heterostructures

Science.gov (United States)

Liu, Ruoyu; Hu, Peiguang; Chen, Shaowei

2012-10-01

Heterostructures based on Ag3PO4 nanoparticles and TiO2 nanobelts were prepared by a coprecipitation method. The crystalline structures were characterized by X-ray diffraction measurements. Electron microscopic studies showed that the Ag3PO4 nanoparticles and TiO2 nanobelts were in intimate contact which might be exploited to facilitate charge transfer between the two semiconductor materials. In fact, the heterostructures exhibited markedly enhanced photocatalytic activity as compared with unmodified TiO2 nanobelts or commercial TiO2 colloids in the photodegradation of methyl orange under UV irradiation. This was accounted for by the improved efficiency of interfacial charge separation thanks to the unique alignments of their band structures. Remarkably, whereas the photocatalytic activity of the heterostructure was comparable to that of Ag3PO4 nanoparticles alone, the heterostructures exhibited significantly better stability and reusability in repeated tests than the Ag3PO4 nanoparticles.

Charge density modification of carboxylated cellulose nanocrystals for stable silver nanoparticles suspension preparation

International Nuclear Information System (INIS)

Hoeng, Fanny; Denneulin, Aurore; Neuman, Charles; Bras, Julien

2015-01-01

Synthesis of silver nanoparticles using cellulose nanocrystals (CNC) has been found to be a great method for producing metallic particles in a sustainable way. In this work, we propose to evaluate the influence of the charge density of 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO)-oxidized CNC on the morphology and the stability of synthetized silver nanoparticles. Silver nanoparticles were obtained by sol–gel reaction using borohydride reduction, and charge density of TEMPO-oxidized CNC was tuned by an amine grafting. The grafting was performed at room temperature and neutral pH. Crystallinity and morphology were kept intact during the peptidic reaction on CNC allowing knowing the exact impact of the charge density. Charge density has been found to have a strong impact on shape, organization, and suspension stability of resulting silver particles. Results show an easy way to tune the charge density of CNC and propose a sustainable way to control the morphology and stability of silver nanoparticles in aqueous suspension

Fungus mediated biosynthesis of WO3 nanoparticles using Fusarium solani extract

Science.gov (United States)

Kavitha, N. S.; Venkatesh, K. S.; Palani, N. S.; Ilangovan, R.

2017-05-01

Currently nanoparticles were synthesized by emphasis bioremediation process due to less hazardous, eco-friendly and imperative applications on biogenic process. Fungus mediated biosynthesis strategy has been developed to prepare tungsten oxide nanoflakes (WO3, NFs) using the plant pathogenic fungus F.solani. The powder XRD pattern revealed the monoclinic crystal structure with improved crystalline nature of the synthesized WO3 nanoparticles. FESEM images showed the flake-like morphology of WO3, with average thickness and length around 40 nm and 300 nm respectively. The Raman spectrum of WO3 NFs showed their characteristic vibration modes that revealed the defect free nature of the WO3 NFs. Further, the elemental analysis indicated the stoichiometric composition of WO3 phase.

Fabrication of hematite (α-Fe{sub 2}O{sub 3}) nanoparticles using electrochemical deposition

Energy Technology Data Exchange (ETDEWEB)

Meng, Qingling; Wang, Zuobin, E-mail: wangz@cust.edu.cn; Chai, Xiangyu; Weng, Zhankun; Ding, Ran; Dong, Litong

2016-04-15

Graphical abstract: - Highlights: • Cathodic electrochemical deposition proposed to fabricate hematite nanoparticles. • Hematite nanoparticles were fabricated on indium-tin-oxide coated glass substrates. • The size and shape of nanoparticles were determined by deposition conditions. • The nanoparticles were well decentralized for different potential applications. • Electrochemical deposition is a useful approach in fabricating nanoparticles. - Abstract: In this work, cathodic electrochemical deposition was proposed to fabricate reproducible and homogeneous hematite (α-Fe{sub 2}O{sub 3}) nanoparticles on indium-tin-oxide (ITO) films. The α-Fe{sub 2}O{sub 3} nanoparticles, which were quasi-hexagonally shaped, were deposited in an aqueous mixture of FeCl{sub 2} and FeCl{sub 3} at the temperatures 16.5 °C, 40 °C and 60 °C. The electrochemically deposited α-Fe{sub 2}O{sub 3} nanoparticles showed excellent stability and good crystallinity. The α-Fe{sub 2}O{sub 3} nanoparticles were characterized by Raman spectroscope and X-ray diffractometer (XRD). A scanning electron microscope (SEM) was used to measure the size and shape of the nanoparticles. The experiment results have shown that the size and shape of nanoparticles were determined by electrochemical deposition conditions including the deposition time, current density, reaction temperature and solution concentration. The proposed electrochemical deposition method has been proven to be a cost-effective, environment friendly and highly efficient approach in fabricating well decentralized α-Fe{sub 2}O{sub 3} nanoparticles for different potential applications.

Facile preparation of superhydrophobic surfaces based on metal oxide nanoparticles

Science.gov (United States)

Bao, Xue-Mei; Cui, Jin-Feng; Sun, Han-Xue; Liang, Wei-Dong; Zhu, Zhao-Qi; An, Jin; Yang, Bao-Ping; La, Pei-Qing; Li, An

2014-06-01

A novel method for fabrication of superhydrophobic surfaces was developed by facile coating various metal oxide nanoparticles, including ZnO, Al2O3 and Fe3O4, on various substrates followed by treatment with polydimethylsiloxane (PDMS) via chemical vapor deposition (CVD) method. Using ZnO nanoparticles as a model, the changes in the surface chemical composition and crystalline structures of the metal oxide nanoparticles by PDMS treatment were investigated by X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD) and Fourier transform infrared (FTIR) analysis. The results show that the combination of the improved surface roughness generated from of the nanoparticles aggregation with the low surface-energy of silicon-coating originated from the thermal pyrolysis of PDMS would be responsible for the surface superhydrophobicity. By a simple dip-coating method, we show that the metal oxide nanoparticles can be easily coated onto the surfaces of various textural and dimensional substrates, including glass slide, paper, fabric or sponge, for preparation of superhydrophobic surfaces for different purpose. The present strategy may provide an inexpensive and new route to surperhydrophobic surfaces, which would be of technological significance for various practical applications especially for separation of oils or organic contaminates from water.

Facile preparation of superhydrophobic surfaces based on metal oxide nanoparticles

International Nuclear Information System (INIS)

Bao, Xue-Mei; Cui, Jin-Feng; Sun, Han-Xue; Liang, Wei-Dong; Zhu, Zhao-Qi; An, Jin; Yang, Bao-Ping; La, Pei-Qing; Li, An

2014-01-01

A novel method for fabrication of superhydrophobic surfaces was developed by facile coating various metal oxide nanoparticles, including ZnO, Al 2 O 3 and Fe 3 O 4 , on various substrates followed by treatment with polydimethylsiloxane (PDMS) via chemical vapor deposition (CVD) method. Using ZnO nanoparticles as a model, the changes in the surface chemical composition and crystalline structures of the metal oxide nanoparticles by PDMS treatment were investigated by X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD) and Fourier transform infrared (FTIR) analysis. The results show that the combination of the improved surface roughness generated from of the nanoparticles aggregation with the low surface-energy of silicon-coating originated from the thermal pyrolysis of PDMS would be responsible for the surface superhydrophobicity. By a simple dip-coating method, we show that the metal oxide nanoparticles can be easily coated onto the surfaces of various textural and dimensional substrates, including glass slide, paper, fabric or sponge, for preparation of superhydrophobic surfaces for different purpose. The present strategy may provide an inexpensive and new route to surperhydrophobic surfaces, which would be of technological significance for various practical applications especially for separation of oils or organic contaminates from water.