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Sample records for include carbon microspheres

  1. Preparation of multilayer carbon microspheres by using graphitic carbon nitride as precursor

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xuefei, E-mail: wuxt12@mails.jlu.edu.cn; Wu, Xingtong

    2015-11-15

    Multilayer carbon microspheres were synthesized by using graphitic Carbon Nitride as precursor. The result of SEM and TEM showed that micrometer-sized multilayer spherical carbon structure had been prepared without the designed addition of any catalyst or template. The composition of the sample indicated that the sample was pure carbon materials. The result of XRD and Raman revealed low graphitization degree of carbon microspheres. FTIR and the analysis of theoretical spectra calculated by using GAUSSIAN 03 program indicated carbon microspheres structure model consisted of many five-member carbon rings. It also can be the cause of the low graphitized degree.

  2. Synthesis and characterization of carbon microsphere for extinguishing sodium fire

    Science.gov (United States)

    Snehalatha, V.; Ponraju, D.; Nashine, B. K.; Chellapandi, P.

    2013-06-01

    In Sodium cooled Fast breeder Reactors (SFRs), accidental leakage of liquid sodium leads to sodium fire. Carbon microsphere is a promising and novel extinguishant for sodium fire since it possesses high thermal conductivity, chemical inertness and excellent flow characteristics. Low density Carbon microsphere (CMS) with high thermal stability was successfully synthesized from functionalized styrene divinyl benzene copolymer by carbonization under inert atmosphere. Protocol for stepwise carbonization was developed by optimizing heating rate and time of heating. The synthesized CMS was characterized by Densimeter, Scanning Electron Microscope (SEM), Fourier Transfer Infra-Red spectroscopy (FTIR), Thermogravimetry (TG), X-ray Diffraction (XRD) and RAMAN spectroscopy. CMS thus obtained was spherical in shape having diameters ranging between 60 to 80μm with narrow size distribution. The smooth surface of CMS ensures its free flow characteristics. The yield of carbonization process was about 38%. The performance of CMS was tested on small scale sodium. This paper describes the development of carbon microsphere for extinguishing sodium fire and its characteristics.

  3. Preparing microspheres of actinide nitrides from carbon containing oxide sols

    International Nuclear Information System (INIS)

    Triggiani, L.V.

    1975-01-01

    A process is given for preparing uranium nitride, uranium oxynitride, and uranium carboxynitride microspheres and the microspheres as compositions of matter. The microspheres are prepared from carbide sols by reduction and nitriding steps. (Official Gazette)

  4. Preparation of PVA/amino multi-walled carbon nanotubes nanocomposite microspheres for endotoxin adsorption.

    Science.gov (United States)

    Zong, Wenhui; Chen, Jian; Han, Wenyan; Cheng, Guanghui; Chen, Jie; Wang, Yue; Wang, Weichao; Ou, Lailiang; Yu, Yaoting; Shen, Jie

    2018-02-01

    A novel polyvinyl alcohol-amino multi-walled carbon nanotube (PVA-AMWCNT) nanocomposite microsphere was prepared successfully for the first time and used for endotoxin removal. The resulting AMWCNT modified PVA microsphere was characterized by SEM, Raman spectrum and fluorescence image, which indicated AMWCNT was dispersed into the macropores of PVA microsphere uniformly. The PVA-AMWCNT microspheres showed better adsorption capability and faster adsorption equilibrium for endotoxin in aqueous solution when compared to the PVA microsphere with polymyxin B (PMB) as ligand. More noteworthy, the PVA based microspheres had little nonspecific adsorption in simulated serum. Therefore, PVA-AMWCNT nanocomposite microsphere with an excellent haemocompatibility has a great potential application in clinical blood purification.

  5. Waxberry-like carbon@polyaniline microspheres with high-performance microwave absorption

    Science.gov (United States)

    Yu, Lujun; Zhu, Yaofeng; Fu, Yaqin

    2018-01-01

    Polyaniline (PANI) nanorod arrays were facilely grown on the surface of carbon microspheres via a simple dilute polymerization. The as-synthesized carbon@polyaniline nanorod arrays microspheres (C@PANI) show specific waxberry-like shape, and exhibit superior microwave absorption capacities compared with pure PANI and carbon microsphere. The minimum reflection loss (RL) value of C@PANI microspheres reaches -59.6 dB at 15.5 GHz with a thin thickness of 2.2 mm and the effective bandwidth (reflection loss values of less than -10 dB) is as wide as 5.4 GHz (from 12.6 to 18 GHz). The in-depth analyses of the geometrical shape and composition relationship demonstrate that the enhanced microwave absorption properties of C@PANI microspheres was mainly correlate with the unique PANI nanorod arrays and synergistic effect.

  6. Capacitive behavior of carbon nanotube thin film induced by deformed ZnO microspheres

    Science.gov (United States)

    Tripathi, Rahul; Naidu Majji, Shanmukh; Ghosh, Rituparna; Nandi, Sukanta; Boruah, Buddha D.; Misra, Abha

    2017-09-01

    Multiwalled carbon nanotubes (CNTs) are uniformly distributed with piezoelectric microspheres. This leads to a large strain gradient due to an induced capacitive response, providing a 250% enhancement in electromechanical response compared with pristine CNTs. The fabricated large-area flexible thin film exhibits excellent pressure sensitivity, which can even detect an arterial pulse with a much faster response time (˜79 ms) in a bendable configuration. In addition, the film shows a rapid relaxation time (˜0.4 s), high stability and excellent durability with a rapid loading-unloading cycle. The dominant contribution of piezoelectric microspheres in a CNT matrix as opposed to nanoparticles showed a much higher sensitivity due to the large change in capacitance. Therefore, hybrid microstructures have various potential applications in wearable smart electronics, including detection of human motion and wrist pulses.

  7. The electrical transport properties of nitrogen doped carbon microspheres

    International Nuclear Information System (INIS)

    Wright, W.P.; Marsicano, V.D.; Keartland, J.M.; Erasmus, R.M.; Dube, S.M.A.; Coville, N.J.

    2014-01-01

    Four samples of nitrogen-doped carbon microspheres were synthesised using a horizontal chemical vapour deposition process. Characterization of the samples using scanning electron microscopy, Raman spectroscopy and electron paramagnetic resonance spectroscopy showed spherical graphitic carbon microparticles with substitutional nitrogen in the lattice structure. The average diameter of the microspheres was 1.7 μm. Electron paramagnetic resonance spectroscopy was also used as a technique to measure the percentage of substitutional nitrogen in each sample. This was determined to be 3.4% in two of the samples and 1.7% in the other two. Temperature dependent electrical transport measurements were performed on the samples and resistance measurements showed clear semiconducting behaviour in two of the samples and a transition from metallic to semiconducting behaviour in the other two samples. IV characteristics measurements display curves with increasing non-linearity as temperature decreases in two samples and saturation behaviour is seen at higher temperatures in the other two samples. An anomaly is present in the IV characteristics at 300 K in all samples. A combination of fluctuation induced tunnelling and electronphonon scattering is used to model the data. These models provide a satisfactory description of the data for both the IV characteristics and the resistance measurements. - Highlights: • Nitrogen doped carbon spheres were synthesised using a horizontal CVD technique. • SEM, EPR, and Raman spectroscopy confirmed the synthesis was successful. • Electrical transport measurements (resistance and IV characteristics) were done. • Variable temperature resistance measurements showed the samples conducted via FIT. • This result was confirmed with variable temperature IV characteristics

  8. Biomineralized multifunctional magnetite/carbon microspheres for applications in Li-ion batteries and water treatment.

    Science.gov (United States)

    Shim, Hyun-Woo; Park, Sangbaek; Song, Hee Jo; Kim, Jae-Chan; Jang, Eunjin; Hong, Kug Sun; Kim, T Doohun; Kim, Dong-Wan

    2015-03-16

    Advanced functional materials incorporating well-defined multiscale architectures are a key focus for multiple nanotechnological applications. However, strategies for developing such materials, including nanostructuring, nano-/microcombination, hybridization, and so on, are still being developed. Here, we report a facile, scalable biomineralization process in which Micrococcus lylae bacteria are used as soft templates to synthesize 3D hierarchically structured magnetite (Fe3O4) microspheres for use as Li-ion battery anode materials and in water treatment applications. Self-assembled Fe3O4 microspheres with flower-like morphologies are systematically fabricated from biomineralized 2D FeO(OH) nanoflakes at room temperature and are subsequently subjected to post-annealing at 400 °C. In particular, because of their mesoporous properties with a hollow interior and the improved electrical conductivity resulting from the carbonized bacterial templates, the Fe3 O4 microspheres obtained by calcining the FeO(OH) in Ar exhibit enhanced cycle stability and rate capability as Li-ion battery anodes, as well as superior adsorption of organic pollutants and toxic heavy metals. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Preparation and antibacterial property of silver decorated carbon microspheres

    Science.gov (United States)

    Li, Sha; Yan, Xiaoliang; Yang, Zhi; Yang, Yongzhen; Liu, Xuguang; Zou, Jing

    2014-02-01

    Carbon microspheres (CMSs) were prepared by glucose hydrothermal method. The effects of glucose concentration and reaction time on the size and morphology of CMSs were studied. CMSs with surface area of 642.5 m2/g and pore size of 0.8 nm were exploited to design hybrid material of CMSs with Ag decoration by radio frequency plasma (RF plasma). A series of investigations using X-ray diffraction, UV-vis spectrometry, Fourier transform infrared spectrometry, X-ray photoelectron spectrometry, thermogravimetric analysis, scanning electron microscopy, energy dispersive X-ray spectroscopy, and transmission electron microscopy was carried out to characterize the Ag decorated CMSs. RF plasma was employed to reduce Ag+ ions to metallic nano-particles with the particle size of 10-20 nm and form a clean metal-support (Ag-CMSs) interface. The mechanism for the structure formation of Ag decorated CMSs was discussed. Plasma produced Ag/CMSs showed antibacterial property and proved suitable for potential biological and environmental applications.

  10. Facile synthesis of magnetic mesoporous hollow carbon microspheres for rapid capture of low-concentration peptides.

    Science.gov (United States)

    Cheng, Gong; Zhou, Ming-Da; Zheng, Si-Yang

    2014-08-13

    Mesoporous and hollow carbon microspheres embedded with magnetic nanoparticles (denoted as MHM) were prepared via a facile self-sacrificial method for rapid capture of low-abundant peptides from complex biological samples. The morphology, structure, surface property, and magnetism were well-characterized. The hollow magnetic carbon microspheres have a saturation magnetization value of 130.2 emu g(-1) at room temperature and a Brunauer-Emmett-Teller specific surface area of 48.8 m(2) g(-1) with an average pore size of 9.2 nm for the mesoporous carbon shell. The effectiveness of these MHM affinity microspheres for capture of low-concentration peptides was evaluated by standard peptides, complex protein digests, and real biological samples. These multifunctional hollow carbon microspheres can realize rapid capture and convenient separation of low-concentration peptides. They were validated to have better performance than magnetic mesoporous silica and commercial peptide-enrichment products. In addition, they can be easily recycled and present excellent reusability. Therefore, it is expected that this work may provide a promising tool for high-throughput discovery of peptide biomarkers from biological samples for disease diagnosis and other biomedical applications.

  11. Biomimetic mineralization of calcium carbonate/carboxymethylcellulose microspheres for lysozyme immobilization

    International Nuclear Information System (INIS)

    Lu Zheng; Zhang Juan; Ma Yunzi; Song Siyue; Gu Wei

    2012-01-01

    Porous calcium carbonate/carboxymethylcellulose (CaCO 3 /CMC) microspheres were prepared by the biomimetic mineralization method for lysozyme immobilization via adsorption. The size and morphology of CaCO 3 /CMC microspheres were characterized by transmitted electron microscopy (TEM) and zeta potential measurement. The lysozyme immobilization was verified by Fourier transform infrared (FTIR) spectroscopy. The effects of pHs and temperatures on lysozyme adsorption were investigated as well. It was revealed that CaCO 3 /CMC microspheres could immobilize lysozyme efficiently via electrostatic interactions and a maximum adsorption capacity of 450 mg/g was achieved at pH 9.2 and 25 °C. Moreover, it was found that the adsorption process fitted well with the Langmuir isothermal model. In addition, UV, fluorescence, and circular dichroism (CD) spectroscopic studies showed that lysozyme maintained its original secondary structure during the adsorption/desorption process. Our study therefore demonstrated that CaCO 3 /CMC microsphere can be used as a cost-effective and efficient support for lysozyme immobilization. - Graphical abstract: CaCO 3 /CMC microsphere was prepared by a facile biomimetic mineralization method and can be used as an efficient and cost-effective support for lysozyme immobilization. Highlights: ► CaCO 3 /CMC microspheres were prepared by the biomimetic mineralization method. ► Lysozyme was efficiently immobilized to CaCO 3 /CMC microspheres via adsorption. ► A maximum adsorption capacity of 450 mg/g was obtained at pH 9.2 and 25 °C. ► The original secondary structure of lysozyme was maintained upon immobilization.

  12. Carbon Hollow Microspheres with a Designable Mesoporous Shell for High-Performance Electromagnetic Wave Absorption.

    Science.gov (United States)

    Xu, Hailong; Yin, Xiaowei; Zhu, Meng; Han, Meikang; Hou, Zexin; Li, Xinliang; Zhang, Litong; Cheng, Laifei

    2017-02-22

    In this work, mesoporous carbon hollow microspheres (PCHMs) with designable mesoporous shell and interior void are constructed by a facile in situ stöber templating approach and a pyrolysis-etching process. The PCHMs are characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectra, Raman spectroscopy, and nitrogen adsorption and desorption system. A uniform mesoporous shell (pore size 4.7 nm) with a thickness of 55 nm and a cavity size of 345 nm is realized. The composite of paraffin mixed with 20 wt % PCHMs exhibits a minimum reflection coefficient (RC min ) of -84 dB at 8.2 GHz with a sample thickness of 3.9 mm and an effective absorption bandwidth (EAB) of 4.8 GHz below -10 dB (>90% electromagnetic wave is attenuated). Moreover, the composite of phenolic resin mixed with 20 wt % PCHMs exhibits an ultrawide EAB of 8 GHz below -10 dB with a thinner thickness of 2.15 mm. Such excellent electromagnetic wave absorption properties are ascribed to the large carbon-air interface in the mesoporous shell and interior void, which is favorable for the matching of characteristic impedance as compared with carbon hollow microspheres and carbon solid microspheres. Considering the excellent performance of PCHMs, we believe the as-fabricated PCHMs can be promising candidates as highly effective microwave absorbers, and the design philosophy can be extended to other spherical absorbers.

  13. Natural reducing agents for electroless nanoparticle deposition: Mild synthesis of metal/carbon nanostructured microspheres

    International Nuclear Information System (INIS)

    Duffy, Paul; Reynolds, Lyndsey A.; Sanders, Stephanie E.; Metz, Kevin M.; Colavita, Paula E.

    2013-01-01

    Composite materials are of interest because they can potentially combine the properties of their respective components in a manner that is useful for specific applications. Here, we report on the use of coffee as a low-cost, green reductant for the room temperature formation of catalytically active, supported metal nanoparticles. Specifically, we have leveraged the reduction potential of coffee in order to grow Pd and Ag nanoparticles at the surface of porous carbon microspheres synthesized via ultraspray pyrolysis. The metal nanoparticle-on-carbon microsphere composites were characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and thermal gravimetric analysis (TGA). To demonstrate the catalytic activity of Pd/C and Ag/C materials, Suzuki coupling reactions and nitroaromatic reduction reactions were employed, respectively. - Highlights: • Natural reductants were used as green electroless deposition reagents. • Room temperature synthesis of supported Ag and Pd nanoparticles was achieved. • Carbon porous microspheres were used as supports. • Synthesis via natural reductants yielded catalytically active nanoparticles.

  14. Natural reducing agents for electroless nanoparticle deposition: Mild synthesis of metal/carbon nanostructured microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Duffy, Paul [School of Chemistry, University of Dublin Trinity College, College Green, Dublin 2 (Ireland); Reynolds, Lyndsey A.; Sanders, Stephanie E. [Department of Chemistry, Albion College, 611 E. Porter St., Albion, MI 49224 (United States); Metz, Kevin M., E-mail: kmetz@albion.edu [Department of Chemistry, Albion College, 611 E. Porter St., Albion, MI 49224 (United States); Colavita, Paula E., E-mail: colavitp@tcd.ie [School of Chemistry, University of Dublin Trinity College, College Green, Dublin 2 (Ireland); Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2 (Ireland)

    2013-06-15

    Composite materials are of interest because they can potentially combine the properties of their respective components in a manner that is useful for specific applications. Here, we report on the use of coffee as a low-cost, green reductant for the room temperature formation of catalytically active, supported metal nanoparticles. Specifically, we have leveraged the reduction potential of coffee in order to grow Pd and Ag nanoparticles at the surface of porous carbon microspheres synthesized via ultraspray pyrolysis. The metal nanoparticle-on-carbon microsphere composites were characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and thermal gravimetric analysis (TGA). To demonstrate the catalytic activity of Pd/C and Ag/C materials, Suzuki coupling reactions and nitroaromatic reduction reactions were employed, respectively. - Highlights: • Natural reductants were used as green electroless deposition reagents. • Room temperature synthesis of supported Ag and Pd nanoparticles was achieved. • Carbon porous microspheres were used as supports. • Synthesis via natural reductants yielded catalytically active nanoparticles.

  15. Scalable and sustainable synthesis of carbon microspheres via a purification-free strategy for sodium-ion capacitors

    Science.gov (United States)

    Wang, Shijie; Wang, Rutao; Zhang, Yabin; Jin, Dongdong; Zhang, Li

    2018-03-01

    Sodium-based energy storage receives a great deal of interest due to the virtually inexhaustible sodium reserve, while the scalable and sustainable strategies to synthesize carbon-based materials with suitable interlayer spaces and large sodium storage capacities are yet to be fully investigated. Carbon microspheres, with regular geometry, non-graphitic characteristic, and stable nature are promising candidates, yet the synthetic methods are usually complex and energy consuming. In this regard, we report a scalable purification-free strategy to synthesize carbon microspheres directly from 5 species of fresh juice. As-synthesized carbon microspheres exhibit dilated interlayer distance of 0.375 nm and facilitate Na+ uptake and release. For example, such carbon microsphere anodes have a specific capacity of 183.9 mAh g-1 at 50 mA g-1 and exhibit ultra-stability (99.0% capacity retention) after 10000 cycles. Moreover, via facile activation, highly porous carbon microsphere cathodes are fabricated and show much higher energy density at high rate than commercial activated carbon. Coupling the compelling anodes and cathodes above, novel sodium-ion capacitors show the high working potential up to 4.0 V, deliver a maximum energy density of 52.2 Wh kg-1, and exhibit an acceptable capacity retention of 85.7% after 2000 cycles.

  16. Hierarchical Mn2O3 Microspheres In-Situ Coated with Carbon for Supercapacitors with Highly Enhanced Performances

    Directory of Open Access Journals (Sweden)

    Feilong Gong

    2017-11-01

    Full Text Available Porous Mn2O3 microspheres have been synthesized and in-situ coated with amorphous carbon to form hierarchical C@Mn2O3 microspheres by first producing MnCO3 microspheres in solvothermal reactions, and then annealing at 500 °C. The self-assembly growth of MnCO3 microspheres can generate hollow structures inside each of the particles, which can act as micro-reservoirs to store biomass-glycerol for generating amorphous carbon onto the surfaces of Mn2O3 nanorods consisting of microspheres. The C@Mn2O3 microspheres, prepared at 500 °C, exhibit highly enhanced pseudocapacitive performances when compared to the particles after annealed at 400 °C and 600 °C. Specifically, the C@Mn2O3 microspheres prepared at 500 °C show high specific capacitances of 383.87 F g−1 at current density of 0.5 A g−1, and excellent cycling stability of 90.47% of its initial value after cycling for 5000 times. The asymmetric supercapacitors assembled with C@Mn2O3 microspheres after annealed at 500 °C and activated carbon (AC show an energy density of up to 77.8 Wh kg−1 at power density of 500.00 W kg−1, and a maximum power density of 20.14 kW kg−1 at energy density of 46.8 Wh kg−1. We can attribute the enhanced electrochemical performances of the materials to their three-dimensional (3D hierarchical structure in-situ coated with carbon.

  17. Lead recovery and glass microspheres synthesis from waste CRT funnel glasses through carbon thermal reduction enhanced acid leaching process.

    Science.gov (United States)

    Mingfei, Xing; Yaping, Wang; Jun, Li; Hua, Xu

    2016-03-15

    In this study, a novel process for detoxification and reutilization of waste cathode ray tube (CRT) funnel glass was developed by carbon thermal reduction enhanced acid leaching process. The key to this process is removal of lead from the CRT funnel glass and synchronous preparation of glass microspheres. Carbon powder was used as an isolation agent and a reducing agent. Under the isolation of the carbon powder, the funnel glass powder was sintered into glass microspheres. In thermal reduction, PbO in the funnel glass was first reduced to elemental Pb by carbon monoxide and then located on the surface of glass microspheres which can be removed easily by acid leaching. Experimental results showed that temperature, carbon adding amount and holding time were the major parameters that controlled lead removal rate. The maximum lead removal rate was 94.80% and glass microspheres that measured 0.73-14.74μm were obtained successfully by setting the temperature, carbon adding amount and holding time at 1200°C, 10% and 30min, respectively. The prepared glass microspheres may be used as fillers in polymer materials and abrasive materials, among others. Accordingly, this study proposed a practical and economical process for detoxification and recycling of waste lead-containing glass. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Fabrication of flower-like tin/carbon composite microspheres as long-lasting anode materials for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Tae-Woo [Department of Chemical Engineering, College of Engineering, Hanyang University, Seoul, 133-791 (Korea, Republic of); Lim, Hyung-Seok [Department of WCU Engineering, College of Engineering, Hanyang University, Seoul, 133-791 (Korea, Republic of); Park, Seong-Jin [Department of Chemical Engineering, College of Engineering, Hanyang University, Seoul, 133-791 (Korea, Republic of); Sun, Yang-Kook [Department of WCU Engineering, College of Engineering, Hanyang University, Seoul, 133-791 (Korea, Republic of); Suh, Kyung-Do, E-mail: kdsuh@hanyang.ac.kr [Department of Chemical Engineering, College of Engineering, Hanyang University, Seoul, 133-791 (Korea, Republic of)

    2017-01-01

    In this work, we report the fabrication of the flower-like tin/carbon (Sn/C) composite microspheres using sulfonated semi-interpenetrating polystyrene (SPS) microspheres as a carbon precursor. The sulfonation degree of SPS has great effects on the resulting particle size, morphology, amount of introduced Sn, and the carbonization yield of the microspheres after heat treatment. The obtained Sn/C composite microspheres were characterized by scanning electron microscopy (SEM), focused-ion beam SEM, and X-ray diffraction. The flower-like Sn/C composite electrodes exhibited higher charge-discharge capacities than those of graphite as an anode material for a lithium ion battery. In addition, they show a long lasting cyclability, even through 400 cycles. - Highlights: • Tin nanocrystals are introduced in flower-like carbon spheres with many ripples. • Long lasting cyclability is exhibited at 1 C rate up to 400 cycles. • Tin content of composite spheres depends on chemical treatment of polymer microspheres.

  19. Unprecedented carbon sub-microspheres with a porous hierarchy for highly efficient oxygen electrochemistry.

    Science.gov (United States)

    Zhu, Yun-Pei; Qiao, Shi-Zhang

    2017-12-07

    Developing efficient and robust electrocatalysts for bifunctional oxygen electrocatalysis is crucial for renewable energy technology. Herein, nitrogen and phosphorus co-doped carbon sub-microspheres with fascinating mesostructures are rationally synthesized through an effective soft-templating strategy. The unique features of substantial doping, large surface areas and well-defined porosity endow the dual-doped carbons with high-density electroactive sites, considerable active surface areas and improved mass transfer, ensuring impressive activity and durability in catalyzing oxygen reduction and evolution reactions, even competing with the noble metal benchmarks, thus assuring their use as an air cathode in a rechargeable Zn-air battery with low charge-discharge overpotential and remarkable long-term stability.

  20. Polymeric microspheres

    Science.gov (United States)

    Walt, David R.; Mandal, Tarun K.; Fleming, Michael S.

    2004-04-13

    The invention features core-shell microsphere compositions, hollow polymeric microspheres, and methods for making the microspheres. The microspheres are characterized as having a polymeric shell with consistent shell thickness.

  1. Carbon xerogel microspheres and monoliths from resorcinol-formaldehyde mixtures with varying dilution ratios: preparation, surface characteristics, and electrochemical double-layer capacitances.

    Science.gov (United States)

    Zapata-Benabithe, Zulamita; Carrasco-Marín, Francisco; de Vicente, Juan; Moreno-Castilla, Carlos

    2013-05-21

    Carbon xerogels in the form of microspheres and monoliths were obtained from the sol-gel polymerization of resorcinol and formaldehyde in the presence of potassium carbonate as catalyst, using water as solvent and two different molar dilution ratios. The objectives of this study were as follows: to investigate the effect of the dilution ratio, polymerization reaction time, and temperature on the rheological properties of the sols used to prepare the carbon xerogel microspheres and monoliths; and to determine the influence of their preparation methods and shapes on their surface characteristics and electrochemical double-layer (EDL) capacitance. An increase in the molar dilution ratio produced a decrease in the apparent activation energy of the sol-gel transition. Carbon xerogel microspheres were steam-activated at different burnoff percentages. The morphology, surface area, porosity, and surface chemistry of samples were determined. The main difference between the carbon xerogel microspheres and monoliths was that the latter are largely mesoporous. Better electrochemical behavior was shown by carbon xerogels in monolith than in microsphere form, but higher gravimetric and volumetric capacitances were found in activated carbon xerogel microspheres than in carbon xerogel monoliths.

  2. The effect of selective internal radiation therapy with yttrium-90 resin microspheres on lung carbon monoxide diffusion capacity.

    Science.gov (United States)

    Ones, Tunc; Eryuksel, Emel; Baltacioglu, Feyyaz; Ceyhan, Berrin; Erdil, Tanju Yusuf

    2017-12-29

    Selective internal radiation therapy (SIRT) with embolization of branches of the hepatic artery is a valuable therapeutic tool for patients with hepatic malignancies; however, it is also associated with lung injury risk due to shunting. Diffusion capacity of the lungs for carbon monoxide (DLCO) is a clinically significant lung function test, and worsening in DLCO is suggested to reflect a limited gas exchange reserve caused by the potential toxicity of chemoradiotherapy or it may be a marker of related lung injury. This study aimed to examine the changes in DLCO during SIRT with resin microspheres in newly treated and retreated patients. Forty consecutive patients who received SIRT for a variety of malignant conditions were included. All subjects were treated with Yttrium-90 labelled resin microspheres. DLCO tests were performed after the procedures. In addition, patients were specifically followed for radiation pneumonitis. The mean DLCO did not significantly change after the first (82.8 ± 19.4 vs. 83.1 ± 20.9, p = 0.921) and the second treatments (87.4 ± 19.7 vs. 88.6 ± 23.2, p = 0.256). Proportion of patients with impaired DLCO at baseline was not altered significantly after the first (37.5 vs. 45.0%, p = 0.581) and the second treatments (27.3 vs. 27.3%, p = 1.000). Also, percent change in DLCO values did not correlate with radiation dose, lung shunt fraction, or lung exposure dose (p > 0.05 for all comparisons). None of the patients developed radiation pneumonitis. Our results suggest that no significant change in DLCO in association with SIRT occurs, both after the first or the second treatment sessions. Further larger studies possibly with different protocols are warranted to better delineate DLCO changes after SIRT in a larger spectrum of patients.

  3. Effects of Amino-Functionalized Carbon Nanotubes on the Crystal Structure and Thermal Properties of Polyacrylonitrile Homopolymer Microspheres

    Directory of Open Access Journals (Sweden)

    Hailong Zhang

    2017-08-01

    Full Text Available Amino-functionalized multi-walled carbon nanotube (amino-CNT/polyacrylonitrile (PAN microspheres with diameter of about 300–400 nm were prepared by in situ polymerization under aqueous solution. The morphology, crystal structure, and thermal properties of amino-CNTs on a PAN homopolymer were investigated by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectra, X-ray diffraction, and differential scanning calorimetry. The results showed that the amino-CNTs had a significant influence on the morphology of microspheres, and the PAN matrix were grafted onto the surface of amino-CNTs with interfacial bonding between them. The XRD studies showed that the crystal size of amino-CNT/PAN microspheres with lower crystallinity was bigger than in the control PAN homopolymer. The analysis of thermal properties indicated that the amino-CNT/PAN microspheres with lower glass transition temperature had a lower initial temperature and velocity of evolving heat during the exothermic processing as compared with the PAN homopolymer. These results suggested that the incorporation of amino-CNTs into the PAN homopolymer matrix was beneficial for controlling the heat released during the stabilization processing.

  4. Enabling high-rate electrochemical flow capacitors based on mesoporous carbon microspheres suspension electrodes

    Science.gov (United States)

    Tian, Meng; Sun, Yueqing; Zhang, Chuanfang (John); Wang, Jitong; Qiao, Wenming; Ling, Licheng; Long, Donghui

    2017-10-01

    Electrochemical flow capacitor (EFC) is a promising technology for grid energy storage, which combines the fast charging/discharging capability of supercapacitors with the scalable energy capacity of flow batteries. In this study, we report a high-power-density EFC using mesoporous carbon microspheres (MCMs) as suspension electrodes. By using a simple yet effective spray-drying technique, monodispersed MCMs with average particle size of 5 μm, high BET surface area of 1150-1267 m2 g-1, large pore volume of 2-4 cm3 g-1 and controllable mesopore size of 7-30 nm have been successfully prepared. The resultant MCMs suspension electrode shows excellent stability and considerable high capacitance of 100 F g-1 and good cycling ability (86% of initial capacitance after 10000 cycles). Specially, the suspension electrode exhibits excellent rate performance with 75% capacitance retention from 2 to 100 mV s-1, significantly higher than that of microporous carbon electrodes (20∼30%), due to the developed mesoporous channels facilitating for rapid ion diffusion. In addition, the electrochemical responses on both negative and positive suspension electrodes are studied, based on which an optimal capacitance matching between them is suggested for large-scale EFC unit.

  5. Coating magnesium hydroxide on surface of carbon microspheres and interface binding with poly (ethylene terephthalate) matrix

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Baoxia [Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Ministry of Education, Taiyuan 030024 (China); Research Center on Advanced Materials Science and Technology, Taiyuan University of Technology, Taiyuan 030024 (China); College of Textile Engineering, Taiyuan University of Technology, Yuci 030600 (China); Niu, Mei, E-mail: niumei@tyut.edu.cn [Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Ministry of Education, Taiyuan 030024 (China); College of Textile Engineering, Taiyuan University of Technology, Yuci 030600 (China); Yang, Yongzhen, E-mail: yyztyut@126.com [Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Ministry of Education, Taiyuan 030024 (China); Research Center on Advanced Materials Science and Technology, Taiyuan University of Technology, Taiyuan 030024 (China); Bai, Jie; Song, Yinghao; Peng, Yun [College of Textile Engineering, Taiyuan University of Technology, Yuci 030600 (China); Liu, Xuguang [Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Ministry of Education, Taiyuan 030024 (China); College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024 (China)

    2017-08-01

    Highlights: • Magnesium hydroxide (MH) as a capsule wall was firstly coated on the surface of carbon microspheres (CMSs) to obtain MH@CMSs by liquid phase deposition method. • An organic layer of 3-Aminopropyltriethoxysilane (APTS) was then introduced on the surface of MH@CMSs. • The formed two layers provided the FMH@CMSs/PET with good mechanical and flame-retardant properties. - Abstract: In this account, magnesium hydroxide (MH) employed as a capsule wall was firstly coated on the surface of carbon microspheres (CMSs) to obtain MH@CMSs using liquid phase deposition, then was modified by 3-Aminopropyltriethoxysilane (APTS) to form FMH@CMSs. To investigate the interface binding forces, a series of PET composites was prepared by melt compounding with MH@CMSs or FMH@CMSs. Field-emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM), Fourier-transform Infrared spectrometry (FTIR) and X-ray photoelectron spectroscopy (XPS) were used to characterize the morphology, chemical structure, and effect of functionalization of CMSs. The coating degree and thermal stability were investigated by thermogravimetry analysis. The results showed that CMSs were coated by an inorganic shell layer of MH as a capsule wall. On the other hand, MH@CMSs were coated with an organic layer of APTS. When compared to MH@CMSs, the interface binding forces between FMH@CMSs and PET matrix were significantly improved, and the tensile strength of FMH@CMSs/PET was higher than that of MH@CMSs/PET. At 1 wt% mass fraction of FMH@CMSs, the limiting oxygen index (LOI) value of PET composites increased from 21% to 27.6% following a V-0 rating. The tensile strength of FMH@CMSs/PET increased by 66.2% to reach 47.20 MPa, a value nearly similar to that of PET. Overall, the formed two layers provided the FMH@CMSs/PET with good mechanical and flame-retardant properties, which would broaden their scope of application.

  6. CARBON CRYOGEL MICROSPHERE FOR ETHYL LEVULINATE PRODUCTION: EFFECT OF CARBONIZATION TEMPERATURE AND TIME

    Directory of Open Access Journals (Sweden)

    MUZAKKIR M. ZAINOL

    2016-07-01

    Full Text Available The side products of biomass and bio-fuel industry have shown potential in producing carbon catalyst. The carbon cryogel was synthesized from ligninfurfural mixture based on the following details: 1.0 of lignin to furfural (L/F ratio, 1.0 of lignin to water (L/W ratio, and 8M of acid concentration. The lignin-furfural sol-gel mixture, initially prepared via polycondensation reaction at 90 °C for 30 min, was followed by freeze drying and carbonization process. Effects of carbonization temperature and time were investigated on the total acidity and surface area of the carbon cryogel. Furthermore, the effects of these parameters were studied on the ethyl levulinate yield through esterification reaction of levulinic acid in ethanol. The esterification reaction was conducted at reflux temperature, 10 h of reaction time, 19 molar ratio of ethanol to levulinic acid, and 15.0 wt.% carbon cryogel loading. Based on the carbonization temperature and time studies, the carbon cryogel carbonized at 500 °C and 4 h exhibited good performance as solid acid catalyst. Large total surface area and acidity significantly influenced the catalytic activity of carbon cryogel with 80.0 wt.% yield of ethyl levulinate. Thus, carbon cryogel is highly potential as acid catalyst for the esterification of levulinic acid with ethanol.

  7. Tailoring the morphology of raspberry-like carbon black/polystyrene composite microspheres for fabricating superhydrophobic surface

    International Nuclear Information System (INIS)

    Bao, Yubin; Li, Qiuying; Xue, Pengfei; Huang, Jianfeng; Wang, Jibin; Guo, Weihong; Wu, Chifei

    2011-01-01

    In our previous report, raspberry-like carbon black/polystyrene (CB/PS) composite microsphere was prepared through heterocoagulation process. Based on the previous study, in the present work, the morphology of raspberry-like CB/PS particle is tailored through adjusting the polarity and the concentration ratio of CB/PS colloidal suspension with the purpose to prepare particulate film for the fabrication of superhydrophobic surface. Scanning electron microscope (SEM) confirms the morphology of raspberry-like particle and the coverage of CB. Rough surfaces fabricated by raspberry-like particles with proper morphology are observed by SEM and clear evidence of superhydrophobic surface is shown. The structure of raspberry-like particle is analyzed by atom force microscope. The proposed relationship between the hydrophobicity and the structure of CB aggregates on the surface of PS microsphere is discussed in details.

  8. Adsorption of Organic Dyes by TiO2@Yeast-Carbon Composite Microspheres and Their In Situ Regeneration Evaluation

    Directory of Open Access Journals (Sweden)

    Zheng Pei

    2015-01-01

    Full Text Available TiO2@yeast-carbon microspheres with raspberry-like morphology were fabricated based on the pyrolysis method. The obtained products were characterized by field emission scanning electron microscopy (FE-SEM, energy dispersive spectrometry (EDS, and X-ray diffraction (XRD. Effects of initial dye concentration and contact time on adsorption capacity of TiO2@yeast-carbon for cationic dye methylene blue (MB and anionic dye congo red (CR were investigated. Experimental data were described by Langmuir, Freundlich, Temkin, and Koble-Corrigan isotherm models, respectively. It was found that the equilibrium data of MB adsorption were best represented by Koble-Corrigan, and CR adsorption was best described by both Freundlich and Koble-Corrigan isotherm models. The kinetic data of MB and CR adsorption fitted pseudo-second-order kinetic model well. The results demonstrated that TiO2@yeast-carbon microspheres achieved favorable removal for the cationic MB in comparison with that for the anionic CR. In addition, regeneration experimental results showed that TiO2@yeast-carbon exhibited good recycling stability, reusability, and in situ renewability, suggesting that the as-prepared TiO2@yeast-carbon might be used as the potential low cost alternative for recalcitrant dye removal from industrial wastewater. One possible mechanism for regenerating dye-loaded TiO2@yeast in situ was also proposed.

  9. Metallic coating of microspheres

    International Nuclear Information System (INIS)

    Meyer, S.F.

    1980-01-01

    Extremely smooth, uniform metal coatings of micrometer thicknesses on microscopic glass spheres (microspheres) are often needed as targets for inertial confinement fusion (ICF) experiments. The first part of this paper reviews those methods used successfully to provide metal coated microspheres for ICF targets, including magnetron sputtering, electro- and electroless plating, and chemical vapor pyrolysis. The second part of this paper discusses some of the critical aspects of magnetron sputter coating of microspheres, including substrate requirements, the sticking of microspheres during coating (preventing a uniform coating), and the difficulties in growing the desired dense, smooth, uniform microstructure on continuously moving spherical substrates

  10. Metallic coating of microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, S.F.

    1980-08-15

    Extremely smooth, uniform metal coatings of micrometer thicknesses on microscopic glass spheres (microspheres) are often needed as targets for inertial confinement fusion (ICF) experiments. The first part of this paper reviews those methods used successfully to provide metal coated microspheres for ICF targets, including magnetron sputtering, electro- and electroless plating, and chemical vapor pyrolysis. The second part of this paper discusses some of the critical aspects of magnetron sputter coating of microspheres, including substrate requirements, the sticking of microspheres during coating (preventing a uniform coating), and the difficulties in growing the desired dense, smooth, uniform microstructure on continuously moving spherical substrates.

  11. Persistent cyclestability of carbon coated Zn–Sn metal oxide/carbon microspheres as highly reversible anode material for lithium-ion batteries

    International Nuclear Information System (INIS)

    Fang, Guoqing; Kaneko, Shingo; Liu, Weiwei; Xia, Bingbo; Sun, Hongdan; Zhang, Ruixue; Zheng, Junwei; Li, Decheng

    2013-01-01

    Development of high-capacity anode materials equipped with strong cyclestability is a great challenge for use as practical electrode for high-performance lithium-ion rechargeable battery. In this study, we synthesized a carbon coated Zn–Sn metal nanocomposite oxide and carbon spheres (ZTO@C/CSs) via a simple glucose hydrothermal reaction and subsequent carbonization approach. The carbon coated ZTO/carbon microspheres composite maintained a reversible capacity of 680 mAh g −1 after 345 cycles at a current density of 100 mA g −1 , and furthermore the cell based on the composite exhibited an excellent rate capability of 470 mAh g −1 even when the cell was cycled at 2000 mA g –1 . The thick carbon layer formed on the ZTO nanoparticles and carbon spheres effectively buffered the volumetric change of the particles, which thus prolonged the cycling performance of the electrodes

  12. Mussel-inspired polydopamine coated hollow carbon microspheres, a novel versatile filler for fabrication of high performance syntactic foams.

    Science.gov (United States)

    Zhang, Liying; Roy, Sunanda; Chen, Ye; Chua, Eng Kee; See, Kye Yak; Hu, Xiao; Liu, Ming

    2014-01-01

    Syntactic foams, which can be synthesized by mechanical mixing of hollow microspheres with a matrix material, are a special class of lightweight composite materials. Developing of high-performance syntactic foams remains challenges. In this work, a facile and environmentally friendly surface modification method employing polydopamine (PDA) as a surface treatment agent for hollow carbon microspheres (HCMs) was used, aiming to extend the application of syntactic foams to seldom touched areas. The PDA coating was used as a strategy for interfacial interaction enhancement and also as a platform for further metal coating meant for electromagnetic interference (EMI) shielding. The stronger interfacial interaction between microspheres and polymer matrix provided effective interfacial stress transfer, as a result of the syntactic foams with high strength to weight ratio. Furthermore, the PDA coating on HCMs served as a versatile platform for the growth of noble metals on the surface of PDA-HCMs. Silver nanoparticles was grown by PDA medium. The silver coated HCMs (Ag-PDA-HCMs) impacted the complex permittivity of the syntactic foams leading to high EMI shielding effectiveness (SE). The specific EMI SE reached up to 46.3 dB·cm(3)/g, demonstrated the Ag-PDA-HCMs/epoxy syntactic foam as a promising candidate for lightweight high-performance EMI shielding material.

  13. Multi-functional carbon microspheres with double shell layers for flame retardant poly (ethylene terephthalate)

    Science.gov (United States)

    Xue, Baoxia; Niu, Mei; Yang, Yongzhen; Bai, Jie; Song, Yinghao; Peng, Yun; Liu, Xuguang

    2018-03-01

    Carbon microspheres (CMSs) as a core material had been coated by two capsule walls: an inorganic material of magnesium hydroxide (MH) as inner shell layer and an organic material of poly (ethylene terephthalate) (PET) as outer shell layer. MH coating CMSs (MCMSs) were fabricated by liquid phase deposition method, then grafted 3-Aminopropyltriethoxysilane (APTS) to obtain the Si-MCMSs. Microencapsulated Si-MCMSs (PMCMSs) was prepared by in situ polymerization method. Morphology structure, dispersion, flame retardant and other properties of PMCMSs have been investigated. A series of PET blends were prepared by melt compounding. The results showed that MH and PET as two layers were coated on CMSs surface with the optimal thickness of about 70 nm. The PMCMSs owned better dispersion in PET matrix. Compared with MCMSs/PET composites, the mechanical property of PMCMSs/PET composites had significantly increased because of the strong interface binding force between PMCMSs and PET matrix. Moreover, PMCMSs was proved to be an effective flame retardant. For PMCMSs/PET with 2 wt% PMCMSs, the limiting oxygen index (LOI) value increased from 21.0% (pristine PET) to 27.2%, and the peak heat release rate (pk-HRR) decreased from 513.22 kW/m2 to 352.14 kW/m2. The decreased smoke production rate (SPR) and total smoke production (TSP) values demonstrated PMCMSs suppressed the smoke production. The increased Fire performance index (FPI) value illustrated PMCMSs significantly reduced the fire risk of PET. Overall, the two capsular walls endowed the PMCMSs/PET composites with good mechanical and flame-retardant properties.

  14. Coating magnesium hydroxide on surface of carbon microspheres and interface binding with poly (ethylene terephthalate) matrix

    Science.gov (United States)

    Xue, Baoxia; Niu, Mei; Yang, Yongzhen; Bai, Jie; Song, Yinghao; Peng, Yun; Liu, Xuguang

    2017-08-01

    In this account, magnesium hydroxide (MH) employed as a capsule wall was firstly coated on the surface of carbon microspheres (CMSs) to obtain MH@CMSs using liquid phase deposition, then was modified by 3-Aminopropyltriethoxysilane (APTS) to form FMH@CMSs. To investigate the interface binding forces, a series of PET composites was prepared by melt compounding with MH@CMSs or FMH@CMSs. Field-emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM), Fourier-transform Infrared spectrometry (FTIR) and X-ray photoelectron spectroscopy (XPS) were used to characterize the morphology, chemical structure, and effect of functionalization of CMSs. The coating degree and thermal stability were investigated by thermogravimetry analysis. The results showed that CMSs were coated by an inorganic shell layer of MH as a capsule wall. On the other hand, MH@CMSs were coated with an organic layer of APTS. When compared to MH@CMSs, the interface binding forces between FMH@CMSs and PET matrix were significantly improved, and the tensile strength of FMH@CMSs/PET was higher than that of MH@CMSs/PET. At 1 wt% mass fraction of FMH@CMSs, the limiting oxygen index (LOI) value of PET composites increased from 21% to 27.6% following a V-0 rating. The tensile strength of FMH@CMSs/PET increased by 66.2% to reach 47.20 MPa, a value nearly similar to that of PET. Overall, the formed two layers provided the FMH@CMSs/PET with good mechanical and flame-retardant properties, which would broaden their scope of application.

  15. Uniform Yolk-Shell MoS2@Carbon Microsphere Anodes for High-Performance Lithium-Ion Batteries.

    Science.gov (United States)

    Pan, Yunmei; Zhang, Jiajia; Lu, Hongbin

    2017-07-21

    As an electrode material for lithium-ion batteries (LIBs), MoS 2 has attracted much attention because of its high capacity and low cost. However, the rational design of a novel electrode structure with a high capacity, fast charge/discharge rate, and long cycling lifetime remains a great challenge. Herein, a environmentally friendly etching strategy is reported for the construction of monodisperse, inner void-controlled yolk-shell MoS 2 @carbon microspheres. The resulting anode reveals an initial discharge capacity up to 1813 mAh g -1 , a high reversible capacity (1016 mAh g -1 ), excellent cycling stability (200 cycles), and superior rate performance. Such microspheres consist of nanosized MoS 2 yolks (≈280 nm), porous carbon shells (≈25 nm) and well-controlled internal voids in between, opening a new pathway for the optimization of the electrochemical properties of MoS 2 -based anodes without sacrificing their capacity. In addition, this etching strategy offers a new method for the development of functional, hollow MoS 2 -based composites. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Removal mechanism of selenite by Fe{sub 3}O{sub 4}-precipitated mesoporous magnetic carbon microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Jianwei; Fu, Fenglian, E-mail: fufenglian2006@163.com; Ding, Zecong; Li, Na; Tang, Bing

    2017-05-15

    Highlights: • MCMSs were prepared via green hydrothermal carbonization and coprecipitation. • MCMSs displayed effective removal of Se(IV) from wastewater. • Se(IV) formed inner-sphere complexes with MCMSs and was reduced to insoluble Se{sup 0}. • MCMSs can be easily separated and recycled by an external magnetic field. - Abstract: A mesoporous composite of magnetic carbon microspheres (MCMSs) was synthesized via introducing Fe{sub 3}O{sub 4} nanoscale particles to the surface of carbon microspheres (CMSs) by coprecipitation. Scanning electron microscopy and transmission electron microscopy showed the Fe{sub 3}O{sub 4} nanoscale particles were dispersedly immobilized on the surface of CMSs. The MCMSs demonstrated effective removal of selenite (Se(IV)) from wastewater. MCMSs showed the regular pattern where the lower pH value, the lower residual Se(IV) concentration. The coexisting sulfate, nitrate, chloride, carbonate, and silicate had no significant effect on Se(IV) removal, whereas phosphate hindered the removal of Se(IV) by competing with Se(IV) and formed inner–sphere complexes with Fe{sub 3}O{sub 4} on the surface of MCMSs. Through X–ray photoelectron spectroscopy analysis, Se(IV) can not only form inner–sphere complexes with MCMSs, but also be reduced to insoluble elemental selenium (Se{sup 0}) by Fe{sub 3}O{sub 4} which was oxidized and formed γ–Fe{sub 2}O{sub 3}. Moreover, the superparamagnetic MCMSs can be easily separated from solution by means of an external magnetic field. The high removal efficiency for Se(IV) and rapid separability of MCMSs made them promising materials for the application in the practice.

  17. Novel mesoporous graphitic carbon nitride modified PbBiO2Br porous microspheres with enhanced photocatalytic performance.

    Science.gov (United States)

    Wang, Bin; Di, Jun; Liu, Gaopeng; Yin, Sheng; Xia, Jiexiang; Zhang, Qi; Li, Huaming

    2017-12-01

    Sustainable mesoporous graphitic carbon nitride (mpg-C 3 N 4 ) modified PbBiO 2 Br porous microsphere (mpg-C 3 N 4 /PbBiO 2 Br) had been successfully synthesized via solvothermal process. Multiple techniques were applied to explore the structure, morphology, optical and electronic properties of the as-prepared photocatalysts. It could be found that the mpg-C 3 N 4 was uniformly distributed on the surface of the PbBiO 2 Br porous microsphere. Compared with the pure PbBiO 2 Br, the mpg-C 3 N 4 /PbBiO 2 Br exhibited superior photocatalytic activity for the degradation of organic pollutants under visible light irradiation. When the mass fraction of mpg-C 3 N 4 was 3%, the mpg-C 3 N 4 /PbBiO 2 Br composite materials exhibited the highest photocatalytic performance. The results indicated that the introduction of mpg-C 3 N 4 could effectively enhance the electron mobility to promote the catalytic activity. The enhanced photocatalytic activity of the mpg-C 3 N 4 /PbBiO 2 Br materials can be attributed to the stronger optical trapping capability and the more effective separation efficiency of photogenerated electron-hole pairs. During the process of photocatalysis, the main active species of the photocatalysts were determined to be the and hole under visible light irradiation. Based on the relative band positions of mpg-C 3 N 4 and PbBiO 2 Br, a possible photocatalytic mechanism of mpg-C 3 N 4 /PbBiO 2 Br composite catalyst was proposed. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Synthesis of morphology-controlled carbon hollow particles by carbonization of resorcinol-formaldehyde precursor microspheres and applications in lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Haijiao, E-mail: seaboyfang@163.com [Modern Manufacture Engineering Center, Heilongjiang Institute of Science and Technology, 150027 (China); Xu Huifang, E-mail: xuhf@hit.edu.cn [School of Chemical Engineering and Technology, Harbin Institute of Technology, 150001 (China); Zhao Can [Modern Manufacture Engineering Center, Heilongjiang Institute of Science and Technology, 150027 (China)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer Resorcinol-formaldehyde hollow particles could be obtained by inverse suspension method. Black-Right-Pointing-Pointer The morphologies of RF carbon precursor particles could be controlled by adjusting the pH values of the RF precursor. Black-Right-Pointing-Pointer The prepared carbon hollow particles, which derived from resorcinol-formaldehyde, exhibited microporous properties. Black-Right-Pointing-Pointer The RF carbon microcapsules displayed excellent power property and cycle durability. - Abstract: The morphology-controlled carbon hollow particles, derived from resorcinol-formaldehyde (RF) particles, were prepared by using an (oil phase) O/(water phase) W/(oil phase) O inverse-emulsion system which was formed by adding RF precursor (water phase) to n-hexane (oil phase) with Span-80 as surfactant and the following carbonization. This simple method led to the formation of various morphologies of RF carbon precursor particles such as hollow spheres, bowl-like hollow structures, microcapsules, or solid microspheres by adjusting the pH values of the RF precursor. The synthesized carbon particles exhibited porous characters with the surface area of 659 m{sup 2} g{sup -1} and the total pore volume of 0.44 cm{sup 3} g{sup -1}. Additionally, the electrochemical behavior of the typical RF carbon particles in lithium-ion batteries revealed that the RF carbon microcapsules displayed a high initial discharge capacity of 1059 mAh g{sup -1} and stabilized at about 330 mAh g{sup -1}, indicating its excellent power property and cycle durability.

  19. Synergistic Ternary Composite (Carbon/Fe3 O4 @Graphene) with Hollow Microspherical and Robust Structure for Li-Ion Storage.

    Science.gov (United States)

    Li, Xingxing; Zheng, Xueying; Shao, Jie; Gao, Tian; Shi, Qiang; Qu, Qunting

    2016-01-04

    The electrode materials with hollow structure and/or graphene coating are expected to exhibit outstanding electrochemical performances in energy-storage systems. 2D graphene-wrapped hollow C/Fe3 O4 microspheres are rationally designed and fabricated by a novel facile and scalable strategy. The core@double-shell structure SPS@FeOOH@GO (SPS: sulfonated polystyrene, GO: graphene oxide) microspheres are first prepared through a simple one-pot approach and then transformed into C/Fe3 O4 @G (G: graphene) after calcination at 500 °C in Ar. During calcination, the Kirkendall effect resulting from the diffusion/reaction of SPS-derived carbon and FeOOH leads to the formation of hollow structure carbon with Fe3 O4 nanoparticles embedded in it. In the rationally constructed architecture of C/Fe3 O4 @G, the strongly coupled C/Fe3 O4 hollow microspheres are further anchored onto 2D graphene networks, achieving a strong synergetic effect between carbon, Fe3 O4 , and graphene. As an anode material of Li-ion batteries (LIBs), C/Fe3 O4 @G manifests a high reversible capacity, excellent rate behavior, and outstanding long-term cycling performance (1208 mAh g(-1) after 200 cycles at 100 mA g(-1) ). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Porous yolk-shell microspheres as N-doped carbon matrix for motivating the oxygen reduction activity of oxygen evolution oriented materials

    Science.gov (United States)

    Zhou, Jinqiu; Wang, Mengfan; Qian, Tao; Liu, Sisi; Cao, Xuecheng; Yang, Tingzhou; Yang, Ruizhi; Yan, Chenglin

    2017-09-01

    It is highly challenging to explore high-performance bi-functional oxygen electrode catalysts for their practical application in next-generation energy storage and conversion devices. In this work, we synthesize hierarchical N-doped carbon microspheres with porous yolk-shell structure (NCYS) as a metal-free electrocatalyst toward efficient oxygen reduction through a template-free route. The enhanced oxygen reduction performances in both alkaline and acid media profit well from the porous yolk-shell structure as well as abundant nitrogen functional groups. Furthermore, such yolk-shell microspheres can be used as precursor materials to motivate the oxygen reduction activity of oxygen evolution oriented materials to obtain a desirable bi-functional electrocatalyst. To verify its practical utility, Zn-air battery tests are conducted and exhibit satisfactory performance, indicating that this constructed concept for preparation of bi-functional catalyst will afford a promising strategy for exploring novel metal-air battery electrocatalysts.

  1. Global anthropogenic emissions of particulate matter including black carbon

    Science.gov (United States)

    Klimont, Zbigniew; Kupiainen, Kaarle; Heyes, Chris; Purohit, Pallav; Cofala, Janusz; Rafaj, Peter; Borken-Kleefeld, Jens; Schöpp, Wolfgang

    2017-07-01

    This paper presents a comprehensive assessment of historical (1990-2010) global anthropogenic particulate matter (PM) emissions including the consistent and harmonized calculation of mass-based size distribution (PM1, PM2. 5, PM10), as well as primary carbonaceous aerosols including black carbon (BC) and organic carbon (OC). The estimates were developed with the integrated assessment model GAINS, where source- and region-specific technology characteristics are explicitly included. This assessment includes a number of previously unaccounted or often misallocated emission sources, i.e. kerosene lamps, gas flaring, diesel generators, refuse burning; some of them were reported in the past for selected regions or in the context of a particular pollutant or sector but not included as part of a total estimate. Spatially, emissions were calculated for 172 source regions (as well as international shipping), presented for 25 global regions, and allocated to 0.5° × 0.5° longitude-latitude grids. No independent estimates of emissions from forest fires and savannah burning are provided and neither windblown dust nor unpaved roads emissions are included. We estimate that global emissions of PM have not changed significantly between 1990 and 2010, showing a strong decoupling from the global increase in energy consumption and, consequently, CO2 emissions, but there are significantly different regional trends, with a particularly strong increase in East Asia and Africa and a strong decline in Europe, North America, and the Pacific region. This in turn resulted in important changes in the spatial pattern of PM burden, e.g. European, North American, and Pacific contributions to global emissions dropped from nearly 30 % in 1990 to well below 15 % in 2010, while Asia's contribution grew from just over 50 % to nearly two-thirds of the global total in 2010. For all PM species considered, Asian sources represented over 60 % of the global anthropogenic total, and residential combustion

  2. Global anthropogenic emissions of particulate matter including black carbon

    Directory of Open Access Journals (Sweden)

    Z. Klimont

    2017-07-01

    Full Text Available This paper presents a comprehensive assessment of historical (1990–2010 global anthropogenic particulate matter (PM emissions including the consistent and harmonized calculation of mass-based size distribution (PM1, PM2. 5, PM10, as well as primary carbonaceous aerosols including black carbon (BC and organic carbon (OC. The estimates were developed with the integrated assessment model GAINS, where source- and region-specific technology characteristics are explicitly included. This assessment includes a number of previously unaccounted or often misallocated emission sources, i.e. kerosene lamps, gas flaring, diesel generators, refuse burning; some of them were reported in the past for selected regions or in the context of a particular pollutant or sector but not included as part of a total estimate. Spatially, emissions were calculated for 172 source regions (as well as international shipping, presented for 25 global regions, and allocated to 0.5°  ×  0.5° longitude–latitude grids. No independent estimates of emissions from forest fires and savannah burning are provided and neither windblown dust nor unpaved roads emissions are included. We estimate that global emissions of PM have not changed significantly between 1990 and 2010, showing a strong decoupling from the global increase in energy consumption and, consequently, CO2 emissions, but there are significantly different regional trends, with a particularly strong increase in East Asia and Africa and a strong decline in Europe, North America, and the Pacific region. This in turn resulted in important changes in the spatial pattern of PM burden, e.g. European, North American, and Pacific contributions to global emissions dropped from nearly 30 % in 1990 to well below 15 % in 2010, while Asia's contribution grew from just over 50 % to nearly two-thirds of the global total in 2010. For all PM species considered, Asian sources represented over 60 % of the global

  3. Glass microsphere lubrication

    Science.gov (United States)

    Geiger, Michelle; Goode, Henry; Ohanlon, Sean; Pieloch, Stuart; Sorrells, Cindy; Willette, Chris

    1991-01-01

    The harsh lunar environment eliminated the consideration of most lubricants used on earth. Considering that the majority of the surface of the moon consists of sand, the elements that make up this mixture were analyzed. According to previous space missions, a large portion of the moon's surface is made up of fine grained crystalline rock, about 0.02 to 0.05 mm in size. These fine grained particles can be divided into four groups: lunar rock fragments, glasses, agglutinates (rock particles, crystals, or glasses), and fragments of meteorite material (rare). Analysis of the soil obtained from the missions has given chemical compositions of its materials. It is about 53 to 63 percent oxygen, 16 to 22 percent silicon, 10 to 16 percent sulfur, 5 to 9 percent aluminum, and has lesser amounts of magnesium, carbon, and sodium. To be self-supporting, the lubricant must utilize one or more of the above elements. Considering that the element must be easy to extract and readily manipulated, silicon or glass was the most logical choice. Being a ceramic, glass has a high strength and excellent resistance to temperature. The glass would also not contaminate the environment as it comes directly from it. If sand entered a bearing lubricated with grease, the lubricant would eventually fail and the shaft would bind, causing damage to the system. In a bearing lubricated with a solid glass lubricant, sand would be ground up and have little effect on the system. The next issue was what shape to form the glass in. Solid glass spheres was the only logical choice. The strength of the glass and its endurance would be optimal in this form. To behave as an effective lubricant, the diameter of the spheres would have to be very small, on the order of hundreds of microns or less. This would allow smaller clearances between the bearing and the shaft, and less material would be needed. The production of glass microspheres was divided into two parts, production and sorting. Production includes the

  4. Evaluation of various carbon blacks and dispersing agents for use in the preparation of uranium microspheres with carbon

    Science.gov (United States)

    Hunt, R. D.; Johnson, J. A.; Collins, J. L.; McMurray, J. W.; Reif, T. J.; Brown, D. R.

    2018-01-01

    A comparison study on carbon blacks and dispersing agents was performed to determine their impacts on the final properties of uranium fuel kernels with carbon. The main target compositions in this internal gelation study were 10 and 20 mol % uranium dicarbide (UC2), which is UC1.86, with the balance uranium dioxide. After heat treatment at 1900 K in flowing carbon monoxide in argon for 12 h, the density of the kernels produced using a X-energy proprietary carbon suspension, which is commercially available, ranged from 96% to 100% of theoretical density (TD), with full conversion of UC to UC2 at both carbon concentrations. However, higher carbon concentrations such as a 2.5 mol ratio of carbon to uranium in the feed solutions failed to produce gel spheres with the proprietary carbon suspension. The kernels using our former baseline of Mogul L carbon black and Tamol SN were 90-92% of TD with full conversion of UC to UC2 at a variety of carbon levels. Raven 5000 carbon black and Tamol SN were used to produce 10 mol % UC2 kernels with 95% of TD. However, an increase in the Raven 5000 concentration led to a kernel density below 90% of TD. Raven 3500 carbon black and Tamol SN were used to make very dense kernels without complete conversion to UC2. The selection of the carbon black and dispersing agent is highly dependent on the desired final properties of the target kernels.

  5. A facile one-pot fabrication of polyphosphazene microsphere/carbon fiber hybrid reinforcement and its effect on the interfacial adhesion of epoxy composites

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xiang [Zhejiang Provincial Key Laboratory of Robotics and Intelligent Manufacturing Equipment Technology, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Science, Ningbo 315201 (China); School of Mechanical and Electronic Engineering, Ningbo Dahongying University, Ningbo 315175 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Xu, Haibing, E-mail: xuhaibing@nimte.ac.cn [Zhejiang Provincial Key Laboratory of Robotics and Intelligent Manufacturing Equipment Technology, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Science, Ningbo 315201 (China); Liu, Dong; Yan, Chun [Zhejiang Provincial Key Laboratory of Robotics and Intelligent Manufacturing Equipment Technology, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Science, Ningbo 315201 (China); Zhu, Yingdan, E-mail: y.zhu@nimte.ac.cn [Zhejiang Provincial Key Laboratory of Robotics and Intelligent Manufacturing Equipment Technology, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Science, Ningbo 315201 (China)

    2017-07-15

    Graphical abstract: Carbon fiber was successfully functionalized with a layer of coating and poly(cyclotriphosphazene-co-4,4′-sulfonyldiphonel) microspheres (PZSMS) by in situ polymerization. The enhancement of surface roughness can improve obviously the interfacial properties through providing more contact points and increasing mechanical interlocking between carbon fiber and epoxy matrix. Moreover, the cyclomatrix-type polyphosphazene coating and PZSMS distributed on the fibers surface can heal the surface defects to some extent and assist in holding back or absorbing excessive stress, resulting in the improvement of tensile strength. - Highlights: • Polyphosphazene microspheres/CF hybrid reinforcements were prepared via a novel and facile one-pot in situ polymerization. • Plenty of poly(cyclotriphosphazene-co-4,4′-sulfonyldiphonel) microspheres were introduced onto the CF surfaces. • The multi-scale hybrid CF reinforcement enhanced the interfacial adhesion of CF/epoxy composites obviously. • The tensile strength of multi-scale hybrid CF also showed an obvious increase. - Abstract: Introducing nanoscale reinforcements into the interface between carbon fiber (CF) and resin is an effective approach to improve the interfacial adhesion of CF composites. In this paper, a facile one-pot polymerization process provides a rapid and efficient method for preparing polyphosphazene microspheres/CF hybrid reinforcement using hexachlorocyclotriphosphazene (HCCP) and bis(4-hydroxyphenyl) sulfone (BPS) as monomers. By the in situ polymerization modification, HCCP and BPS were successfully cross-linked and deposited on the CF surface. Scanning electron microscope and atomic force microscopy images show that poly(cyclotriphosphazene-co-4,4′-sulfonyldiphonel) microspheres were introduced onto the CF surfaces and the surface roughness of fibers is enhanced obviously. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy confirm that the

  6. MoS{sub 2}-coated microspheres of self-sensitized carbon nitride for efficient photocatalytic hydrogen generation under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Quan [Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi’an, 710062 (China); School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Sun, Huaming; Xie, Zunyuan; Gao, Ziwei [Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi’an, 710062 (China); Xue, Can, E-mail: cxue@ntu.edu.sg [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)

    2017-02-28

    Highlights: • Successful coating of MoS{sub 2} onto self-sensitized carbon nitride microspheres. • The carbon nitride@MoS{sub 2} core-shell structure show enhanced H{sub 2} generation in visible light. • Synergistic effect of surface dyes and MoS{sub 2} coating enhances photocatalytic activities. - Abstract: We have successfully coated the self-sensitized carbon nitride (SSCN) microspheres with a layer of MoS{sub 2} through a facile one-pot hydrothermal method by using (NH{sub 4}){sub 2}MoS{sub 4} as the precursor. The resulted MoS{sub 2}-coated SSCN photocatalyst appears as a core-shell structure and exhibits enhanced visible-light activities for photocatalytic H{sub 2} generation as compared to the un-coated SSCN and the standard g-C{sub 3}N{sub 4} reference with MoS{sub 2} coating. The photocatalytic test results suggest that the oligomeric s-triazine dyes on the SSCN surface can provide additional light-harvesting capability and photogenerated charge carriers, and the coated MoS{sub 2} layer can serve as active sites for proton reduction towards H{sub 2} evolution. This synergistic effect of surface triazine dyes and MoS{sub 2} coating greatly promotes the activity of carbon nitride microspheres for vishible-light-driven H{sub 2} generation. This work provides a new way of future development of low-cost noble-metal-free photocatalysts for efficient solar-driven hydrogen production.

  7. Introduction of enzymatically degradable poly(trimethylene carbonate) microspheres into an injectable calcium phosphate cement

    NARCIS (Netherlands)

    Habraken, Wouter J. E. M.; Zhang, Zheng; Wolke, Joop G. C.; Grijpma, Dirk W.; Mikos, Antonios G.; Feijen, Jan; Jansen, John A.

    Poly(trimethylene carbonate) (PTMC) is an enzymatically degradable polyester with rubber-like properties. Introduction of this polymer into an injectable calcium phosphate bone cement can therefore be used to introduce macroporosity into the cement for tissue engineering purposes as well as to

  8. Environmentally benign formation of polymeric microspheres by rapid expansion of supercritical carbon dioxide solution with a nonsolvent.

    Science.gov (United States)

    Matsuyama, K; Mishima, K; Umemoto, H; Yamaguchi, S

    2001-10-15

    A novel method is reported for forming polymer microparticles, which reduce atmospheric emissions of environmentally harmful volatile organic compounds such as toluene and xylene used as paint solvent in paint industry. The polymer microparticles have formed through rapid expansion from supercritical solution with a nonsolvent (RESS-N). Solubilization of poly(styrene)-b-(poly(methyl methacrylate)-co-poly (glycidyl methacrylate)) copolymer(PS-b-(PMMA-co-PGMA), MW = 5000, PS/PMMA/PGMA = 2/5/3), poly(ethylene glycol) (PEG, M. W = 4000), bisphenol A type epoxy resin (EP, MW = 3000), poly(methyl methacrylate) (PMMA; MW = 15000, 75000, 120000), and poly(oxyalkylene) alkylphenyl ether (MW = 4000) in carbon dioxide (CO2) was achieved with the use of small alcohols as cosolvents. The solubility of the PS-b-(PMMA-co-PGMA) is extremely low in either CO2 or ethanol but becomes 20 wt % in a mixture of the two. Because ethanol is a nonsolvent for the polymer, it can be used as a cosolvent in rapid expansion from supercritical solution to produce 1-3 microm particles that do not agglomerate. Obtained polymer particles by RESS-N were applied as powder coatings. The resulting coatings have a smooth and coherent film. The particle size distribution of microspheres was controlled by changing the polymer concentration, preexpansion pressure, temperature, and injection distance. The feed compositions were more effective than the other factors in controlling the particle size. The polymeric microparticles formed by RESS-N method can be utilized to make the thin coating film without anytoxic organic solvents and/or surfactants.

  9. Carbon footprint of milk from sheep farming systems in northern Spain including soil carbon sequestration in grasslands

    DEFF Research Database (Denmark)

    Batalla, Inma M.; Knudsen, Marie Trydeman; Mogensen, Lisbeth

    2015-01-01

    sequestration in the carbon footprint calculations. Especially in grasslands, soil carbon sequestration might be a potential sink to mitigate greenhouse gas emissions in the livestock sector. However, there is no commonly accepted methodology on how to include soil carbon sequestration in carbon footprint...... calculations. In this study, the carbon footprint of sheep milk was estimated from 12 farms in Northern Spain. Before taken into account contribution from soil carbon sequestration in the calculation, the carbon footprint values varied from 2.0 to 5.2 kg CO2 eq. per kg Fat and Protein Corrected Milk (FPCM...... and breeds when soil carbon sequestration was included in the calculations. Four different approaches to estimate and include soil carbon sequestration in the carbon footprint calculations were tested. This study highlights the importance of including soil carbon sequestration in the carbon footprint...

  10. Including carbon emissions from deforestation in the carbon footprint of Brazilian beef.

    Science.gov (United States)

    Cederberg, Christel; Persson, U Martin; Neovius, Kristian; Molander, Sverker; Clift, Roland

    2011-03-01

    Effects of land use changes are starting to be included in estimates of life-cycle greenhouse gas (GHG) emissions, so-called carbon footprints (CFs), from food production. Their omission can lead to serious underestimates, particularly for meat. Here we estimate emissions from the conversion of forest to pasture in the Legal Amazon Region (LAR) of Brazil and present a model to distribute the emissions from deforestation over products and time subsequent to the land use change. Expansion of cattle ranching for beef production is a major cause of deforestation in the LAR. The carbon footprint of beef produced on newly deforested land is estimated at more than 700 kg CO(2)-equivalents per kg carcass weight if direct land use emissions are annualized over 20 years. This is orders of magnitude larger than the figure for beef production on established pasture on non-deforested land. While Brazilian beef exports have originated mainly from areas outside the LAR, i.e. from regions not subject to recent deforestation, we argue that increased production for export has been the key driver of the pasture expansion and deforestation in the LAR during the past decade and this should be reflected in the carbon footprint attributed to beef exports. We conclude that carbon footprint standards must include the more extended effects of land use changes to avoid giving misleading information to policy makers, retailers, and consumers.

  11. Facile fabrication of carbon microspheres decorated with B(OH) 3 and α-Fe 2 O 3 nanoparticles: superior microwave absorption

    KAUST Repository

    Zhong, Bo

    2017-06-02

    We demonstrate that novel three-dimensional (3D) B(OH)3 and α-Fe2O3 nanoparticles decorated carbon microspheres (B(OH)3/α-Fe2O3-CMSs) can be fabricated via a facile thermal treatment process. The carbon microspheres with diameter of 1 to 3 μm and decorated B(OH)3 and α-Fe2O3 nanoparticles with diameters of several to tens of nanometers are successfully fabricated. These novel 3D B(OH)3/α-Fe2O3-CMS composites exhibit enhanced microwave absorption with tunable strong absorption wavebands in the frequency range of 2–18 GHz. They have a minimum reflection loss (RL) value of -52.69 dB at a thickness of 3.0 mm, and the effective absorption bandwidth for RL less than -10 dB is as large as 5.64 GHz. The enhanced microwave absorption performance arises from the synergy of the impedance matching caused by the B(OH)3 nanoparticles, dielectric loss as well as the enhancement of multiple reflection among 3D α-Fe2O3 nanocrystals. These results provide a new strategy to tune electromagnetic properties and enhance the capacity of high-efficient microwave absorbers.

  12. MoS2-coated microspheres of self-sensitized carbon nitride for efficient photocatalytic hydrogen generation under visible light irradiation

    Science.gov (United States)

    Gu, Quan; Sun, Huaming; Xie, Zunyuan; Gao, Ziwei; Xue, Can

    2017-02-01

    We have successfully coated the self-sensitized carbon nitride (SSCN) microspheres with a layer of MoS2 through a facile one-pot hydrothermal method by using (NH4)2MoS4 as the precursor. The resulted MoS2-coated SSCN photocatalyst appears as a core-shell structure and exhibits enhanced visible-light activities for photocatalytic H2 generation as compared to the un-coated SSCN and the standard g-C3N4 reference with MoS2 coating. The photocatalytic test results suggest that the oligomeric s-triazine dyes on the SSCN surface can provide additional light-harvesting capability and photogenerated charge carriers, and the coated MoS2 layer can serve as active sites for proton reduction towards H2 evolution. This synergistic effect of surface triazine dyes and MoS2 coating greatly promotes the activity of carbon nitride microspheres for vishible-light-driven H2 generation. This work provides a new way of future development of low-cost noble-metal-free photocatalysts for efficient solar-driven hydrogen production.

  13. Template-free synthesis of hierarchical yolk-shell Co and N codoped porous carbon microspheres with enhanced performance for oxygen reduction reaction

    Science.gov (United States)

    Chao, Shujun; Cui, Qian; Wang, Kui; Bai, Zhengyu; Yang, Lin; Qiao, Jinli

    2015-08-01

    The structures and compositions of materials have important influences on their performance. Herein, hierarchically structured yolk-shell Co and N codoped porous carbon microspheres (YS-Co/N-PCMs) have been successfully synthesized by using low-cost melamine, formaldehyde and cobalt acetate as raw materials via a facile template-free hydrothermal method and a subsequent pyrolysis. The formation process of the yolk-shell precursor is systematically investigated, involving a morphological evolution process from solid microspheres, ultrathin and wrinkled shells wrap, to yolk-shell structure formation. More importantly, the unique structure combines the favorable features towards oxygen reduction reaction (ORR), such as high surface area, sufficient Co-Nx and graphitic N active sites and suitable pore structures. As a result, the YS-Co/N-PCMs catalyst shows high catalytic activity for ORR in alkaline media for fuel cells, which not only outperforms commercial Pt-based catalysts in terms of resistance to methanol crossover and long-time stability, but is also better than many non-precious metal doped carbon-based catalysts reported previously. In addition, the YS-Co/N-PCMs catalyst also has high catalytic activity toward oxygen evolution reaction (OER). Therefore, the YS-Co/N-PCMs catalyst may serve as a promising alternative to Pt/C catalyst for ORR and OER in alkaline media.

  14. Controllable Hydrothermal Conversion from Ni-Co-Mn Carbonate Nanoparticles to Microspheres

    Directory of Open Access Journals (Sweden)

    Yanqing Tang

    2016-11-01

    Full Text Available Starting from Ni-Co-Mn carbonate nanoparticles prepared by microreaction technology, uniform spherical particles of Ni1/3Co1/3Mn1/3CO3 with a size of 3–4 μm were obtained by a controllable hydrothermal conversion with the addition of (NH42CO3. Based on characterizations on the evolution of morphology and composition with hydrothermal treatment time, we clarified the mechanism of this novel method as a dissolution-recrystallization process, as well as the effects of (NH42CO3 concentration on the morphology and composition of particles. By changing concentrations and the ratio of the starting materials for nano-precipitation preparation, we achieved monotonic regulation on the size of the spherical particles, and the synthesis of Ni0.4Co0.2Mn0.4CO3 and Ni0.5Co0.2Mn0.3CO3, respectively. In addition, the spherical particles with a core-shell structure were preliminarily verified to be available by introducing nano-precipitates with different compositions in the hydrothermal treatment in sequence.

  15. Differential effects of dissolved organic carbon upon re-entrainment and surface properties of groundwater bacteria and bacteria-sized microspheres during transport through a contaminated, sandy aquifer

    Science.gov (United States)

    Harvey, R.W.; Metge, D.W.; Mohanram, A.; Gao, X.; Chorover, J.

    2011-01-01

    Injection-and-recovery studies involving a contaminated, sandy aquifer (Cape Cod, Massachusetts) were conducted to assess the relative susceptibility for in situ re-entrainment of attached groundwater bacteria (Pseudomonas stuzeri ML2, and uncultured, native bacteria) and carboxylate-modified microspheres (0.2 and 1.0 μm diameters). Different patterns of re-entrainment were evident for the two colloids in response to subsequent injections of groundwater (hydrodynamic perturbation), deionized water (ionic strength alteration), 77 μM linear alkylbenzene sulfonates (LAS, anionic surfactant), and 76 μM Tween 80 (polyoxyethylene sorbitan monooleate, a very hydrophobic nonionic surfactant). An injection of deionized water was more effective in causing detachment of micrsopheres than were either of the surfactants, consistent with the more electrostatic nature of microsphere’s attachment, their extreme hydrophilicity (hydrophilicity index, HI, of 0.99), and negative charge (zeta potentials, ζ, of −44 to −49 mv). In contrast, Tween 80 was considerably more effective in re-entraining the more-hydrophobic native bacteria. Both the hydrophilicities and zeta potentials of the native bacteria were highly sensitive to and linearly correlated with levels of groundwater dissolved organic carbon (DOC), which varied modestly from 0.6 to 1.3 mg L−1. The most hydrophilic (0.52 HI) and negatively charged (ζ −38.1 mv) indigenous bacteria were associated with the lowest DOC. FTIR spectra indicated the latter community had the highest average density of surface carboxyl groups. In contrast, differences in groundwater (DOC) had no measurable effect on hydrophilicity of the bacteria-sized microspheres and only a minor effect on their ζ. These findings suggest that microspheres may not be very good surrogates for bacteria in field-scale transport studies and that adaptive (biological) changes in bacterial surface characteristics may need to be considered where there is longer

  16. Microradiographic microsphere manipulator

    Science.gov (United States)

    Singleton, R.M.

    A method and apparatus is disclosed for radiographic characterization of small hollow spherical members (microspheres), constructed of either optically transparent or opaque materials. The apparatus involves a microsphere manipulator which holds a batch of microspheres between two parallel thin plastic films for contact microradiographic characterization or projection microradiography thereof. One plastic film is translated relative to and parallel to the other to roll the microspheres through any desired angle to allow different views of the microspheres.

  17. Including an ocean carbon cycle model into iLOVECLIM (v1.0)

    NARCIS (Netherlands)

    Bouttes, N.; Roche, D.M.V.A.P.; Mariotti, V.; Bopp, L.

    2015-01-01

    The atmospheric carbon dioxide concentration plays a crucial role in the radiative balance and as such has a strong influence on the evolution of climate. Because of the numerous interactions between climate and the carbon cycle, it is necessary to include a model of the carbon cycle within a

  18. Novel Silicon Doped Tin Oxide-Carbon Microspheres as Anode Material for Lithium Ion Batteries: The Multiple Effects Exerted by Doped Si.

    Science.gov (United States)

    Tan, Yuanzhong; Wong, Ka-Wai; Ng, Ka Ming

    2017-12-01

    Silicon doped tin oxide embedded porous carbon microspheres (Si y Sn 1- y O x @C) are synthesized. It is found that the doped Si not only improves the reversibility of lithiation/delithiation reactions, but also prevents Sn from aggregation. In addition, the doped Si introduces extra defects into the carbon matrix and produces Li + conductive Li 4 SiO 4 , which accelerates Li + diffusion. Together with the conductive, porous carbon matrix that provides void space to accommodate the volume change of Sn during charge/discharge cycling, the novel Si y Sn 1- y O x @C exhibits excellent electrochemical performance. It shows a high initial columbic efficiency of 75.9%. A charge (delithiation) capacity of 880.32 mA h g -1 is retained after 150 cycles, i.e., 91% of the initial capacity. These results indicate that the as-synthesized Si y Sn 1- y O x @C is a promising anode material for lithium ion batteries. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Compaction of Ceramic Microspheres, Spherical Molybdenum Powder and Other Materials to 3 GPa

    International Nuclear Information System (INIS)

    Carlson, S R; Bonner, B P; Ryerson, F J; Hart, M M

    2006-01-01

    Pressure-volume relationships were measured at room temperature for eight granular materials and one specimen of epoxy foam. The granular materials included hollow ceramic microspheres, spherical molybdenum powder, Ottawa sand, aluminum, copper, titanium and silicon carbide powders and glassy carbon spheres. Measurements were made to 0.9 GPa in a liquid medium press for all of the granular materials and to 3 GPa in a solid medium press for the ceramic microspheres and molybdenum powder. A single specimen of epoxy foam was compressed to 30 MPa in the liquid medium press. Bulk moduli were calculated as a function of pressure for the ceramic microspheres, the molybdenum powder and three other granular materials. The energy expended in compacting the granular materials was determined by numerically integrating pressure-volume curves. More energy was expended per unit volume in compacting the molybdenum powder to 1 GPa than for the other materials, but compaction of the ceramic microspheres required more energy per gram due to their very low initial density. The merge pressure, the pressure at which all porosity is removed, was estimated for each material by plotting porosity against pressure on a semi-log plot. The pressure-volume curves were then extrapolated to the predicted merge pressures and numerically integrated to estimate the energy required to reach full density for each material. The results suggest that the glassy carbon spheres and the ceramic microspheres would require more energy than the other materials to attain full density

  20. Chemical template-assisted synthesis of monodisperse rattle-type Fe3O4@C hollow microspheres as drug carrier.

    Science.gov (United States)

    Cheng, Lin; Ruan, Weimin; Zou, Bingfang; Liu, Yuanyuan; Wang, Yongqiang

    2017-08-01

    A chemical template strategy was put forward to synthesize monodisperse rattle-type magnetic carbon (Fe 3 O 4 @C) hollow microspheres. During the synthesis procedure, monodisperse Fe 2 O 3 microspheres were used as chemical template, which released Fe 3+ ions in acidic solution and initiated the in-situ polymerization of pyrrole into polypyrrole (PPy) shell. With the continual acidic etching of Fe 2 O 3 microspheres, rattle-type Fe 2 O 3 @PPy microspheres were generated with the cavity appearing between the PPy shell and left Fe 2 O 3 core, which were then transformed into Fe 3 O 4 @C hollow microspheres through calcination in nitrogen atmosphere. Compared with traditional physical template, the shell and cavity of rattle-type hollow microspheres were generated in one step using the chemical template method, which obviously saved the complex procedures including the coating and removal of middle shells. The experimental results exhibited that the rattle-type Fe 3 O 4 @C hollow microspheres with different parameters could be regulated through controlled synthesis of the intermediate Fe 2 O 3 @PPy product. Moreover, when the rattle-type Fe 3 O 4 @C hollow microspheres were investigated as drug carrier, they manifested sustained-release behaviour of doxorubicin, justifying their promising applications as carriers in drug delivery. The aim of the present study was first to synthesize rattle-type Fe 3 O 4 @C hollow microspheres through a simple synthesis method as a drug carrier. Here a chemical template synthesis of rattle-type hollow microspheres was developed, which saved the complex procedures including the coating and removal of middle shells in traditional physical template. Second, all the influence factors in the reaction processes were systematically investigated to obtain rattle-type Fe 3 O 4 @C hollow microspheres with controlled parameters. Third, the rattle-type Fe 3 O 4 @C hollow microspheres were studied as drug carriers and the influences of their

  1. Acrolein Microspheres Are Bonded To Large-Area Substrates

    Science.gov (United States)

    Rembaum, Alan; Yen, Richard C. K.

    1988-01-01

    Reactive cross-linked microspheres produced under influence of ionizing radiation in aqueous solutions of unsaturated aldehydes, such as acrolein, with sodium dodecyl sulfate. Diameters of spheres depend on concentrations of ingredients. If polystyrene, polymethylmethacrylate, or polypropylene object immersed in solution during irradiation, microspheres become attached to surface. Resulting modified surface has grainy coating with reactivity similar to free microspheres. Aldehyde-substituted-functional microspheres react under mild conditions with number of organic reagents and with most proteins. Microsphere-coated macrospheres or films used to immobilize high concentrations of proteins, enzymes, hormones, viruses, cells, and large number of organic compounds. Applications include separation techniques, clinical diagnostic tests, catalytic processes, and battery separators.

  2. Core-shell composite of hierarchical MoS2 nanosheets supported on graphitized hollow carbon microspheres for high performance lithium-ion batteries

    International Nuclear Information System (INIS)

    Xia, Yuan; Wang, Beibei; Zhao, Xiaojun; Wang, Gang; Wang, Hui

    2016-01-01

    In this work, a core-shell composite composed of MoS 2 nanosheets grown on hollow carbon microspheres is synthesized by a hydrothermal and a subsequent annealing route. The result shows that well-graphitized hollow-carbon@highlycrystallineMoS 2 (HC@MoS 2 ) was obtained after the four-step reaction. And it is found that the synthesized MoS 2 is consist of 2H and 1T phases. The lithium storage property of the composite is investigated as an anode material for lithium-ion batteries. Benefited from the special morphology and structure, a stable capacity of 970 mAh g −1 for over 100 cycles at a current density of 0.25 A g −1 is realized on the material. Even at a high current density of 4 A g −1 , a reversible capacity as high as 560 mAh g −1 is delivered. Moreover, the reasons for the excellent electrochemical performance of the material are explored and discussed in detail.

  3. Synthesis and application of carbonated fatty acid esters from carbon dioxide including a life cycle analysis.

    Science.gov (United States)

    Schäffner, Benjamin; Blug, Matthias; Kruse, Daniela; Polyakov, Mykola; Köckritz, Angela; Martin, Andreas; Rajagopalan, Prasanna; Bentrup, Ursula; Brückner, Angelika; Jung, Sebastian; Agar, David; Rüngeler, Bettina; Pfennig, Andreas; Müller, Karsten; Arlt, Wolfgang; Woldt, Benjamin; Grass, Michael; Buchholz, Stefan

    2014-04-01

    Carbon dioxide can be used in various ways as a cheap C1 source. However, the utilization of CO2 requires energy or energy-rich reagents, which leads to further emissions, and therefore, diminishes the CO2-saving potential. Therefore, life cycle assessment (LCA) is required for each process that uses CO2 to provide valid data for CO2 savings. Carbon dioxide can be incorporated into epoxidized fatty acid esters to provide the corresponding carbonates. A robust catalytic process was developed based on simple halide salts in combination with a phase-transfer catalyst. The CO2-saving potential was determined by comparing the carbonates as a plasticizer with an established phthalate-based plasticizer. Although CO2 savings of up to 80 % were achieved, most of the savings arose from indirect effects and not from CO2 utilization. Furthermore, other categories have been analyzed in the LCA. The use of biobased material has a variety of impacts on categories such as eutrophication and marine toxicity. Therefore, the benefits of biobased materials have to be evaluated carefully for each case. Finally, interesting properties as plasticizers were obtained with the carbonates. The volatility and water extraction could be improved relative to the epoxidized system. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Characterization of carbon/carbon composites prepared by different processing routes including liquid pitch densification process

    International Nuclear Information System (INIS)

    Dekeyrel, Alixe; Dourges, Marie-Anne; Weisbecker, Patrick; Pailler, Rene; Allemand, Alexandre; Teneze, Nicolas; Epherre, Jean-Francois

    2013-01-01

    Carbon/carbon composites with an apparent density higher than 1.80 g/cm 3 were prepared using a multi-step densification process. This consists of a pre-densification step followed by pitch impregnation/pyrolysis (I/P) cycles carried out under moderate pressure. Three pre-densification methods were investigated to significantly increase the apparent density of a raw preform to about 1.4 g/cm 3 . These were:(i) impregnation by carbonaceous powder slurry, (ii) film boiling chemical vapor infiltration, (iii) impregnation with a combination of synthetic pitch I/P and carbonaceous powder slurry. Composites were prepared from each of these three pre-densified materials, using a liquid pitch processing route with four I/P cycles with M50 petroleum pitch, under moderate pressures (10 MPa). As a reference a carbon/carbon composite was prepared using four I/P cycles with pitch. All four composites had different microstructural characteristics and different thermal properties. The influence of processing on thermal properties is discussed in relation to the microstructural characteristics. (authors)

  5. An approach to include soil carbon changes in life cycle assessments

    DEFF Research Database (Denmark)

    Petersen, Bjorn Molt; Knudsen, Marie Trydeman; Hermansen, John Erik

    2013-01-01

    Globally, soil carbon sequestration is expected to hold a major potential to mitigate agricultural greenhouse gas emissions. However, the majority of life cycle assessments (LCA) of agricultural products have not included possible changes in soil carbon sequestration. In the present study, a method...... production in China. The suggested approach considers the time of the soil CO2 emissions for the LCA by including the Bern Carbon Cycle Model. Time perspectives of 20,100 and 200 years are used and a soil depth of 0-100 cm is considered. The application of the suggested method showed that the results were...... to estimate carbon sequestration to be included in LCA is suggested and applied to two examples where the inclusion of carbon sequestration is especially relevant: 1) Bioenergy: removal of straw from a Danish soil for energy purposes and 2) Organic versus conventional farming: comparative study of soybean...

  6. Method for calculating carbon footprint of cattle feeds – including contribution from soil carbon changes and use of cattle manure

    DEFF Research Database (Denmark)

    Mogensen, Lisbeth; Kristensen, Troels; Nguyen, T Lan T

    2014-01-01

    Greenhouse gas emissions (GHG) related to feed production is one of the hotspots in livestock production. The aim of this paper was to estimate the carbon footprint of different feedstuffs for dairy cattle using life cycle assessment (LCA). The functional unit was ‘1 kg dry matter (DM) of feed...... fodder crop, an individual production scheme was set up as the basis for calculating the carbon footprint (CF). In the calculations, all fodder crops were fertilized by artificial fertilizer based on the assumption that the environmental burden of using manure is related to the livestock production...... ready to feed’. Included in the study were fodder crops that are grown in Denmark and typically used on Danish cattle farms. The contributions from the growing, processing and transport of feedstuffs were included, as were the changes in soil carbon (soil C) and from land use change (LUC). For each...

  7. Composite carbon foam electrode

    Science.gov (United States)

    Mayer, Steven T.; Pekala, Richard W.; Kaschmitter, James L.

    1997-01-01

    Carbon aerogels used as a binder for granularized materials, including other forms of carbon and metal additives, are cast onto carbon or metal fiber substrates to form composite carbon thin film sheets. The thin film sheets are utilized in electrochemical energy storage applications, such as electrochemical double layer capacitors (aerocapacitors), lithium based battery insertion electrodes, fuel cell electrodes, and electrocapacitive deionization electrodes. The composite carbon foam may be formed by prior known processes, but with the solid particles being added during the liquid phase of the process, i.e. prior to gelation. The other forms of carbon may include carbon microspheres, carbon powder, carbon aerogel powder or particles, graphite carbons. Metal and/or carbon fibers may be added for increased conductivity. The choice of materials and fibers will depend on the electrolyte used and the relative trade off of system resistivty and power to system energy.

  8. Polymeric Microspheres for Medical Applications

    Directory of Open Access Journals (Sweden)

    Ketie Saralidze

    2010-06-01

    Full Text Available Synthetic polymeric microspheres find application in a wide range of medical applications. Among other applications, microspheres are being used as bulking agents, embolic- or drug-delivery particles. The exact composition of the spheres varies with the application and therefore a large array of materials has been used to produce microspheres. In this review, the relation between microsphere synthesis and application is discussed for a number of microspheres that are used for different treatment strategies.

  9. Migration of carbon dioxide included micro-nano bubble water in porous media and its monitoring

    Science.gov (United States)

    Takemura, T.; Hamamoto, S.; Suzuki, K.; Koichi, O.

    2017-12-01

    The distributed CO2 storage is the small scale storage and its located near the emission areas. In the distributed CO2 storage, the CO2 is neutralized by sediment and underground water in the subsurface region (300-500m depth). Carbon dioxide (CO2) included micro-nano bubbles is one approach in neutralizing CO2 and sediments by increasing CO2 volume per unit volume of water and accelerating the chemical reaction. In order to design underground treatment for CO2 gas in the subsurface, it is required to elucidate the behavior of CO2 included micro-nano bubbles in the water. In this study, we carried out laboratory experiment using the soil tank, and measure the amount of leakage of CO2 gas at the surface. In addition, the process of migration of carbon dioxide included micro-nano bubble was monitored by the nondestructive method, wave velocity and resistivity.

  10. Photoluminescence and lasing in whispering gallery mode glass microspherical resonators

    International Nuclear Information System (INIS)

    Ristić, D.; Berneschi, S.; Camerini, M.; Farnesi, D.; Pelli, S.; Trono, C.; Chiappini, A.; Chiasera, A.; Ferrari, M.; Lukowiak, A.; Dumeige, Y.; Féron, P.; Righini, G.C.; Soria, S.; Conti, G. Nunzi

    2016-01-01

    We report experimental results regarding the development of Er 3+ -doped glass microspherical cavities for the fabrication of compact sources at 1.55 μm. We investigate several different approaches in order to fabricate the microspheres including direct melting of Er 3+ -doped glass powders, synthesis of Er 3+ -doped monolithic microspheres by drawing Er 3+ -doped glass, and coating of silica microspheres with an Er 3+ -doped sol–gel layer. Details of the different fabrication processes are presented together with the photoluminescence characterization in free space configuration of the microspheres and of the glass precursor. We have analyzed the photoluminescence spectra of the whispering gallery modes of the microspheres excited using evanescent coupling and we demonstrate tunable laser action in a wide range of wavelengths around 1.55 μm. As much as 90 μW of laser output power was measured in Er 3+ -doped glass microspheres. - Highlights: • Different approaches in microsphere fabrication and various types of post-processing. • Trimming of photorefractive glass microsphere lasers with UV light. • Peak power record of 90 μW by pumping at 1480 nm.

  11. Photoluminescence and lasing in whispering gallery mode glass microspherical resonators

    Energy Technology Data Exchange (ETDEWEB)

    Ristić, D. [Ruđer Bošković Institute, Division of Materials Physics, Laboratory for Molecular Physics, Bijenička c. 54, Zagreb (Croatia); Center of Excellence for Advanced Materials and Sensing Devices, Research unit New Functional Materials, Bijenička c. 54, Zagreb (Croatia); Berneschi, S.; Camerini, M. [IFAC-CNR Istituto di Fisica Applicata, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Farnesi, D.; Pelli, S. [IFAC-CNR Istituto di Fisica Applicata, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Centro Studi e Ricerche ' E. Fermi' , Piazza del Viminale 2, 00184 Roma (Italy); Trono, C. [IFAC-CNR Istituto di Fisica Applicata, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Chiappini, A.; Chiasera, A.; Ferrari, M. [CSMFO Group, Istituto di Fotonica e Nanotecnologie, IFN-CNR, Via alla Cascata 56/C, 38050 Povo-Trento (Italy); Lukowiak, A. [Institute of Low Temperature and Structure Research, PAS, ul. Okolna 2, Wroclaw 50-950 (Poland); Dumeige, Y.; Féron, P. [Laboratoire d' Optronique, (CNRS-UMR 6082-Foton), ENSSAT, 6 rue de Kérampont, 22300 Lannion (France); Righini, G.C. [IFAC-CNR Istituto di Fisica Applicata, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Centro Studi e Ricerche ' E. Fermi' , Piazza del Viminale 2, 00184 Roma (Italy); Soria, S., E-mail: s.soria@ifac.cnr.it [IFAC-CNR Istituto di Fisica Applicata, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Conti, G. Nunzi [IFAC-CNR Istituto di Fisica Applicata, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Centro Studi e Ricerche ' E. Fermi' , Piazza del Viminale 2, 00184 Roma (Italy)

    2016-02-15

    We report experimental results regarding the development of Er{sup 3+}-doped glass microspherical cavities for the fabrication of compact sources at 1.55 μm. We investigate several different approaches in order to fabricate the microspheres including direct melting of Er{sup 3+}-doped glass powders, synthesis of Er{sup 3+}-doped monolithic microspheres by drawing Er{sup 3+}-doped glass, and coating of silica microspheres with an Er{sup 3+}-doped sol–gel layer. Details of the different fabrication processes are presented together with the photoluminescence characterization in free space configuration of the microspheres and of the glass precursor. We have analyzed the photoluminescence spectra of the whispering gallery modes of the microspheres excited using evanescent coupling and we demonstrate tunable laser action in a wide range of wavelengths around 1.55 μm. As much as 90 μW of laser output power was measured in Er{sup 3+}-doped glass microspheres. - Highlights: • Different approaches in microsphere fabrication and various types of post-processing. • Trimming of photorefractive glass microsphere lasers with UV light. • Peak power record of 90 μW by pumping at 1480 nm.

  12. General hypothesis and shell model for the synthesis of semiconductor nanotubes, including carbon nanotubes

    Science.gov (United States)

    Mohammad, S. Noor

    2010-09-01

    Semiconductor nanotubes, including carbon nanotubes, have vast potential for new technology development. The fundamental physics and growth kinetics of these nanotubes are still obscured. Various models developed to elucidate the growth suffer from limited applicability. An in-depth investigation of the fundamentals of nanotube growth has, therefore, been carried out. For this investigation, various features of nanotube growth, and the role of the foreign element catalytic agent (FECA) in this growth, have been considered. Observed growth anomalies have been analyzed. Based on this analysis, a new shell model and a general hypothesis have been proposed for the growth. The essential element of the shell model is the seed generated from segregation during growth. The seed structure has been defined, and the formation of droplet from this seed has been described. A modified definition of the droplet exhibiting adhesive properties has also been presented. Various characteristics of the droplet, required for alignment and organization of atoms into tubular forms, have been discussed. Employing the shell model, plausible scenarios for the formation of carbon nanotubes, and the variation in the characteristics of these carbon nanotubes have been articulated. The experimental evidences, for example, for the formation of shell around a core, dipole characteristics of the seed, and the existence of nanopores in the seed, have been presented. They appear to justify the validity of the proposed model. The diversities of nanotube characteristics, fundamentals underlying the creation of bamboo-shaped carbon nanotubes, and the impurity generation on the surface of carbon nanotubes have been elucidated. The catalytic action of FECA on growth has been quantified. The applicability of the proposed model to the nanotube growth by a variety of mechanisms has been elaborated. These mechanisms include the vapor-liquid-solid mechanism, the oxide-assisted growth mechanism, the self

  13. Glass microspheres for brachytherapy

    International Nuclear Information System (INIS)

    Prado, Miguel O.; Prastalo, Simon; Blaumann, Herman; Longhino, Juan M.; Repetto Llamazares, A.H.V.

    2007-01-01

    We developed the capacity to produce glass microspheres containing in their structure one or more radioactive isotopes useful for brachytherapy. We studied the various facts related with their production: (Rare earth) alumino silicate glass making, glass characterization, microspheres production, nuclear activation through (n,γ) nuclear reactions, mechanical characterization before and after irradiation. Corrosion tests in simulated human plasma and mechanical properties characterization were done before and after irradiation. (author) [es

  14. Improved efficiency of reversed-phase carbon/nanodiamond/polymer core-shell particles for HPLC using carbonized poly(divinylbenzene) microspheres as the core materials.

    Science.gov (United States)

    Hung, Chuan-Hsi; Wiest, Landon A; Singh, Bhupinder; Diwan, Anubhav; Valentim, Michael J C; Christensen, James M; Davis, Robert C; Miles, Andrew J; Jensen, David S; Vail, Michael A; Dadson, Andrew E; Linford, Matthew R

    2013-12-01

    Here, we report efficiencies up to 112,000 plates per meter (a reduced plate height, h, of 2.22) for RP, carbon/nanodiamond/aminopolymer particles using conventional injection conditions in HPLC. This efficiency greatly exceeds our best previously reported value of 71,000 N/m (h = 3.52). The carbon cores used in this study were derived from carbonized poly(divinylbenzene) spheres that were either made in-house by a two-step polymerization procedure or obtained commercially. The resulting particles showed good uniformity and were oxidized in nitric acid to increase their dispersability. X-ray photoelectron spectroscopy confirms particle oxidation and subsequent aminopolymer deposition. Layer-by-layer (LbL) growth of poly(allyamine) and nanodiamond was demonstrated to produce core-shell particles. After LbL growth, the particles were functionalized, sieved, and packed into columns. The column functionalization and packing were reproducible. Van Deemter curves indicated that the commercially obtained poly(divinylbenzene) spheres outperformed those synthesized in our laboratory. The columns appear to be stable at 120°C in a pH 11.3 mobile phase. Longer columns (2.1 × 50 mm) than previously reported were packed. Four essential oils were separated by gradient elution. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Method for sizing hollow microspheres

    Science.gov (United States)

    Farnum, E.H.; Fries, R.J.

    1975-10-29

    Hollow Microspheres may be effectively sized by placing them beneath a screen stack completely immersed in an ultrasonic bath containing a liquid having a density at which the microspheres float and ultrasonically agitating the bath.

  16. Floating microspheres: a review

    Directory of Open Access Journals (Sweden)

    Jagtap Yogesh Mukund

    2012-03-01

    Full Text Available Gastric emptying is a complex process, one that is highly variable and that makes in vivo performance of drug delivery systems uncertain. A controlled drug delivery system with prolonged residence time in the stomach can be of great practical importance for drugs with an absorption window in the upper small intestine. The main limitations are attributed to the inter- and intra-subject variability of gastro-intestinal (GI transit time and to the non-uniformity of drug absorption throughout the alimentary canal. Floating or hydrodynamically controlled drug delivery systems are useful in such applications. Various gastroretentive dosage forms are available, including tablets, capsules, pills, laminated films, floating microspheres, granules and powders. Floating microspheres have been gaining attention due to the uniform distribution of these multiple-unit dosage forms in the stomach, which results in more reproducible drug absorption and reduced risk of local irritation. Such systems have more advantages over the single-unit dosage forms. The present review briefly addresses the physiology of the gastric emptying process with respect to floating drug delivery systems. The purpose of this review is to bring together the recent literature with respect to the method of preparation, and various parameters affecting the performance and characterization of floating microspheres.O esvaziamento gástrico é um processo complexo, com elevada variabilidade e responsável pela incerteza do desempenho dos medicamentos in vivo. Dessa forma, os sistemas de liberação modificada de fármacos, com tempo de residência prolongado no estômago, em especial, considerando aqueles fármacos com janela de absorção na porção superior do intestino delgado, apresentam fundamental importância. As principais limitações relativas à absorção do fármaco são, no geral, atribuídas à variabilidade inter e intra-paciente do tempo de trânsito gastro-intestinal (GI e

  17. Including Effects of Water Stress on Dead Organic Matter Decay to a Forest Carbon Model

    Science.gov (United States)

    Kim, H.; Lee, J.; Han, S. H.; Kim, S.; Son, Y.

    2017-12-01

    Decay of dead organic matter is a key process of carbon (C) cycling in forest ecosystems. The change in decay rate depends on temperature sensitivity and moisture conditions. The Forest Biomass and Dead organic matter Carbon (FBDC) model includes a decay sub-model considering temperature sensitivity, yet does not consider moisture conditions as drivers of the decay rate change. This study aimed to improve the FBDC model by including a water stress function to the decay sub-model. Also, soil C sequestration under climate change with the FBDC model including the water stress function was simulated. The water stress functions were determined with data from decomposition study on Quercus variabilis forests and Pinus densiflora forests of Korea, and adjustment parameters of the functions were determined for both species. The water stress functions were based on the ratio of precipitation to potential evapotranspiration. Including the water stress function increased the explained variances of the decay rate by 19% for the Q. variabilis forests and 7% for the P. densiflora forests, respectively. The increase of the explained variances resulted from large difference in temperature range and precipitation range across the decomposition study plots. During the period of experiment, the mean annual temperature range was less than 3°C, while the annual precipitation ranged from 720mm to 1466mm. Application of the water stress functions to the FBDC model constrained increasing trend of temperature sensitivity under climate change, and thus increased the model-estimated soil C sequestration (Mg C ha-1) by 6.6 for the Q. variabilis forests and by 3.1 for the P. densiflora forests, respectively. The addition of water stress functions increased reliability of the decay rate estimation and could contribute to reducing the bias in estimating soil C sequestration under varying moisture condition. Acknowledgement: This study was supported by Korea Forest Service (2017044B10-1719-BB01)

  18. Controlled Carbon Source Addition to an Alternating Nitrification-Denitrification Wastewater Treatment Process Including Biological P Removal

    DEFF Research Database (Denmark)

    Isaacs, Steven Howard; Henze, Mogens

    1995-01-01

    The paper investigates the effect of adding an external carbon source on the rate of denitrification in an alternating activated sludge process including biological P removal. Two carbon sources were examined, acetate and hydrolysate derived from biologically hydrolyzed sludge. Preliminary batch...... that external carbon source addition may serve as a suitable control variable to improve process performance....... process, the addition of either carbon source to the anoxic zone also resulted in an instantaneous and fairly reproducible increase in the denitrification rate. Some release of phosphate associated with the carbon source addition was observed. With respect to nitrogen removal, these results indicate...

  19. Systems and Methods for Fabricating Carbon Nanotube-Based Vacuum Electronic Devices

    Science.gov (United States)

    Manohara, Harish (Inventor); Toda, Risaku (Inventor); Del Castillo, Linda Y. (Inventor); Murthy, Rakesh (Inventor)

    2015-01-01

    Systems and methods in accordance with embodiments of the invention proficiently produce carbon nanotube-based vacuum electronic devices. In one embodiment a method of fabricating a carbon nanotube-based vacuum electronic device includes: growing carbon nanotubes onto a substrate to form a cathode; assembling a stack that includes the cathode, an anode, and a first layer that includes an alignment slot; disposing a microsphere partially into the alignment slot during the assembling of the stack such that the microsphere protrudes from the alignment slot and can thereby separate the first layer from an adjacent layer; and encasing the stack in a vacuum sealed container.

  20. Meteorological context for fall experiments including distributions of water vapor, ozone, and carbon monoxide

    Science.gov (United States)

    Danielsen, Edwin F.; Gregory, Gerald L.; Sachse, Glen W.; Hill, G. F.; Gaines, Steven E.

    1987-01-01

    Meteorological contexts for the NASA GTE/CITE 1 fall 1983 flight series are presented and discussed. The large-scale wind, cold cloud, and moisture patterns are illustrated by composite diagrams based on the National Oceanic and Atmospheric Administration 700-, 500-, and 250-mbar analyses and the GOES-West broadband and 6.7-micron (water vapor) infrared photographs. Detailed flight path diagrams are included for seven maritime flights and one continental flight in the free troposphere and boundary layer. For three flights from Hickam Field, in Honolulu, HI, to the Intertropical Convergence Zone, vertical profiles of temperature, dew/frost point departures, wind velocity, and ozone, and carbon monoxide mixing ratios are also presented and discussed. Excellent agreement is demonstrated between the in situ and remote measurements. In particular, the predictive and diagnostic value of the 6.7-micron water vapor photographs is demonstrated.

  1. Preparation of alumina microspheres

    International Nuclear Information System (INIS)

    Santos, W.R. dos; Abrao, A.

    1980-01-01

    Inorganic exchangers are widely used for adsorption and column partition chromatography. The main difficulty of using commercial alumina (in powder) for column chromatography is related to its packing, and the operations through the column become diffcult and time-consuming; also it turns to be virtually impossible to use large dimension columns. In order to eliminate these problems, a process for the preparation of alumina micro-spheres was developed as an adaptation of a similar process used to prepare nuclear fuel microspheres (UO 2 , ThO 2 ). The flowsheet of this process is presented together with the analytical results of sphericity after calcination, granulometry, density and characterization by X-ray diffractometry. Solubility tests showed that the so-prepared microspheres are well resistant to strong acids and bases; retention tests showed their efficiency, mainly to copper. (C.L.B.) [pt

  2. Preparation and In-vitro Evaluation of Metformin Microspheres Using ...

    African Journals Online (AJOL)

    . Methods: Metformin microspheres were prepared by non-aqueous solvent evaporation method using various polymers, including ethylcellulose (EC), hydroxypropyl methylcellulose (HPMC), carbopol 934P (CA) and chitosan (CH). The effect ...

  3. Fusion microsphere targets

    International Nuclear Information System (INIS)

    Koo, J.C.

    1980-01-01

    It was shown that a microsphere within the structure limitations is hydrodynamically stable. To insure its perfect formation, the initial chemical compositions must have a blowing capability, more important, the resultant liquid compositions must also have sufficient surface tension and low viscosity

  4. Controlled Carbon Source Addition to an Alternating Nitrification-Denitrification Wastewater Treatment Process Including Biological P Removal

    DEFF Research Database (Denmark)

    Isaacs, Steven Howard; Henze, Mogens

    1995-01-01

    The paper investigates the effect of adding an external carbon source on the rate of denitrification in an alternating activated sludge process including biological P removal. Two carbon sources were examined, acetate and hydrolysate derived from biologically hydrolyzed sludge. Preliminary batch...... experiments performed in 5 liter bottles indicated that the denitrification rate can be instantaneously increased through the addition of either carbon source. The amount by which the rate was increased depended on the amount of carbon added. In the main experiments performed in a pilot scale alternating...... process, the addition of either carbon source to the anoxic zone also resulted in an instantaneous and fairly reproducible increase in the denitrification rate. Some release of phosphate associated with the carbon source addition was observed. With respect to nitrogen removal, these results indicate...

  5. Development of nuclear fuel microsphere handling techniques and equipment

    International Nuclear Information System (INIS)

    Mack, J.E.; Suchomel, R.R.; Angelini, P.

    1979-01-01

    Considerable progress has been made in the development of microsphere handling techniques and equipment for nuclear applications. Work at Oak Ridge National Laboratory with microspherical fuel forms dates back to the early sixties with the development of the sol-gel process. Since that time a number of equipment items and systems specifically related to microsphere handling and characterization have been identified and developed for eventual application in a remote recycle facility. These include positive and negative pressure transfer systems, samplers, weighers, a blender-dispenser, and automated devices for particle size distribution and crushing strength analysis. The current status of these and other components and systems is discussed

  6. Current knowledge on biodegradable microspheres in drug delivery.

    Science.gov (United States)

    Prajapati, Vipul D; Jani, Girish K; Kapadia, Jinita R

    2015-08-01

    Biodegradable microspheres have gained popularity for delivering a wide variety of molecules via various routes. These types of products have been prepared using various natural and synthetic biodegradable polymers through suitable techniques for desired delivery of various challenging molecules. Selection of biodegradable polymers and technique play a key role in desired drug delivery. This review describes an overview of the fundamental knowledge and status of biodegradable microspheres in effective delivery of various molecules via desired routes with consideration of outlines of various compendial and non-compendial biodegradable polymers, formulation techniques and release mechanism of microspheres, patents and commercial biodegradable microspheres. There are various advantages of using biodegradable polymers including promise of development with different types of molecules. Biocompatibility, low dosage and reduced side effects are some reasons why usage biodegradable microspheres have gained in popularity. Selection of biodegradable polymers and formulation techniques to create microspheres is the biggest challenge in research. In the near future, biodegradable microspheres will become the eco-friendly product for drug delivery of various genes, hormones, proteins and peptides at specific site of body for desired periods of time.

  7. Information management for global environmental change, including the Carbon Dioxide Information Analysis Center

    Energy Technology Data Exchange (ETDEWEB)

    Stoss, F.W. [Oak Ridge National Lab., TN (United States). Carbon Dioxide Information Analysis Center

    1994-06-01

    The issue of global change is international in scope. A body of international organizations oversees the worldwide coordination of research and policy initiatives. In the US the National Science and Technology Council (NSTC) was established in November of 1993 to provide coordination of science, space, and technology policies throughout the federal government. NSTC is organized into nine proposed committees. The Committee on Environmental and Natural Resources (CERN) oversees the US Department of Energy`s Global Change Research Program (USGCRP). As part of the USGCRP, the US Department of Energy`s Global Change Research Program aims to improve the understanding of Earth systems and to strengthen the scientific basis for the evaluation of policy and government action in response to potential global environmental changes. This paper examines the information and data management roles of several international and national programs, including Oak Ridge National Laboratory`s (ORNL`s) global change information programs. An emphasis will be placed on the Carbon Dioxide Information Analysis Center (CDIAC), which also serves as the World Data Center-A for Atmospheric Trace Gases.

  8. Monolithic carbon structures including suspended single nanowires and nanomeshes as a sensor platform.

    Science.gov (United States)

    Lim, Yeongjin; Heo, Jeong-Il; Madou, Marc; Shin, Heungjoo

    2013-11-20

    With the development of nanomaterial-based nanodevices, it became inevitable to develop cost-effective and simple nanofabrication technologies enabling the formation of nanomaterial assembly in a controllable manner. Herein, we present suspended monolithic carbon single nanowires and nanomeshes bridging two bulk carbon posts, fabricated in a designed manner using two successive UV exposure steps and a single pyrolysis step. The pyrolysis step is accompanied with a significant volume reduction, resulting in the shrinkage of micro-sized photoresist structures into nanoscale carbon structures. Even with the significant elongation of the suspended carbon nanowire induced by the volume reduction of the bulk carbon posts, the resultant tensional stress along the nanowire is not significant but grows along the wire thickness; this tensional stress gradient and the bent supports of the bridge-like carbon nanowire enhance structural robustness and alleviate the stiction problem that suspended nanostructures frequently experience. The feasibility of the suspended carbon nanostructures as a sensor platform was demonstrated by testing its electrochemical behavior, conductivity-temperature relationship, and hydrogen gas sensing capability.

  9. BIOCOMPATIBLE FLUORESCENT MICROSPHERES: SAFE PARTICLES FOR MATERIAL PENETRATION STUDIES

    Energy Technology Data Exchange (ETDEWEB)

    Farquar, G; Leif, R

    2009-07-15

    Biocompatible polymers with hydrolyzable chemical bonds have been used to produce safe, non-toxic fluorescent microspheres for material penetration studies. The selection of polymeric materials depends on both biocompatibility and processability, with tailored fluorescent properties depending on specific applications. Microspheres are composed of USFDA-approved biodegradable polymers and non-toxic fluorophores and are therefore suitable for tests where human exposure is possible. Micropheres were produced which contain unique fluorophores to enable discrimination from background aerosol particles. Characteristics that affect dispersion and adhesion can be modified depending on use. Several different microsphere preparation methods are possible, including the use of a vibrating orifice aerosol generator (VOAG), a Sono-Tek atomizer, an emulsion technique, and inkjet printhead. Applications for the fluorescent microspheres include challenges for biodefense system testing, calibrants for biofluorescence sensors, and particles for air dispersion model validation studies.

  10. Synthesis of magnetic polymeric microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Gervald, A Yu; Gritskova, Inessa A; Prokopov, Nikolai I [M.V. Lomonosov Moscow State Academy of Fine Chemical Technology, Moscow (Russian Federation)

    2010-05-13

    The key types of magnetic polymeric microspheres are considered. Methods of synthesis of different types of magnetic nanoparticles and of preparation of stable magnetic fluids on their basis are outlined. The overview of the methods for the manufacture of magnetic polymeric microspheres is presented. The effect of the synthesis conditions on the characteristics of magnetic polymeric microspheres such as the diameter and the particle size distribution and the content of magnetic material is discussed by particular examples. The application fields of magnetic polymeric microspheres are briefly surveyed.

  11. Synthesis of magnetic polymeric microspheres

    International Nuclear Information System (INIS)

    Gervald, A Yu; Gritskova, Inessa A; Prokopov, Nikolai I

    2010-01-01

    The key types of magnetic polymeric microspheres are considered. Methods of synthesis of different types of magnetic nanoparticles and of preparation of stable magnetic fluids on their basis are outlined. The overview of the methods for the manufacture of magnetic polymeric microspheres is presented. The effect of the synthesis conditions on the characteristics of magnetic polymeric microspheres such as the diameter and the particle size distribution and the content of magnetic material is discussed by particular examples. The application fields of magnetic polymeric microspheres are briefly surveyed.

  12. Radioactive Microspheres for Medical Applications

    Science.gov (United States)

    HÄfeli, Urs

    This paper reviews the preparation and application of radioactive microspheres for medical purposes. It first discusses the properties of relevant radioisotopes and then explores the diagnostic uses of gamma-emitter labelled microspheres, such as blood flow measurement and imaging of the liver and other organs. The therapeutic uses of alpha- and beta-emitting microspheres, such as radioembolization, local tumour therapy and radiosynovectomy, are then described, and the recent developments in neutron capture therapy using gadolinium microspheres and boron liposomes discussed. The review concludes with some considerations in radiopharmaceutical kit preparations and radioisotope generator use, as well as with some radiobiological and dosimetric concerns.

  13. On-Chip Facile Preparation of Monodisperse Resorcinol Formaldehyde (RF Resin Microspheres

    Directory of Open Access Journals (Sweden)

    Jianmei Wang

    2018-01-01

    Full Text Available Monodisperse resorcinol formaldehyde resin (RF microspheres are an important polymeric material because of their rich surface functional group and uniform structural characteristics and have been increasingly applied as an electrode material, catalyst support, absorbent, and carbon microsphere precursor. The polymerization conditions, such as the gelation/solidification temperature and the residence time, can largely influence the physical properties and the formation of the 3D polymeric network of the RF microspheres as well as the carbon microspheres. However, few studies have reported on the complexity of the gelation and solidification processes of resol. In this work, we developed a new RF microsphere preparation device that contains three units: a droplet generation unit, a curing unit, and a collection unit. In this system, we controlled the gelation and solidification processes of the resol and observed its curing behavior, which helped us to uncover the curing mechanism of resol. Finally, we obtained the optimized polymerization parameters, obtaining uniform RF microspheres with a variation coefficient of 4.94%. The prepared porous RF microspheres presented a high absorption ability, reaching ~90% at 10 min. Thus, our method demonstrated the practicality of on-chip monodisperse microspheres synthesis. The product was useful in drug delivery and adsorbing large poisonous molecules.

  14. Synthesis and Evaluation of Microspherical Li1.2Mn0.54Co0.13Ni0.13O2 through Carbon Dioxides-assisted Co-precipitation Method for Lithium-ion Battery

    International Nuclear Information System (INIS)

    Yan, Wenchao; Jiang, Jicheng; Liu, Wei; Yan, Xiao; Sun, Deye; Jin, Yongcheng; Wang, Jing; Xiang, Lan; Munakata, Hirokazu; Kanamura, Kiyoshi

    2016-01-01

    Lithium-rich layered electrode materials are of interest as a promising candidate of cathodes for lithium-ion batteries because of their excellent electrochemical properties. The electrochemical performance of these materials is mainly regulated by preparation conditions during synthesis and calcination process. Here, microspherical Li 1.2 Mn 0.54 Co 0.13 Ni 0.13 O 2 (LMNCO) particles are synthesized through steady pH value control with carbon dioxides bubbling method in co-precipitation process using a simple reactor. SEM images present that CP-LMNCO sample prepared through the assistance of carbon dioxides has spherical particle morphology, while sample (TP-LMNCO) without carbon dioxides assistance shows large nanoparticles agglomeration. The CP-LMNCO electrode demonstrates superior electrochemical performance, which exhibits capacity retention of 97.76% after 100 cycles compared with only 81.94% for TP-LMNCO electrode at 1C (250 mA g −1 ). Even at a higher current density (5C), the CP-LMNCO electrode shows reversible capacity up to 105.4 mA h g −1 . The remarkably improved electrochemical performance of CP-LMNCO electrode is ascribed to spherical morphology with small surface area which decreases side reactions with electrolyte during cycling and smaller primary sizes which reduce lithium ion (Li + ) diffusion distance. Furthermore, the synthesis of spherical materials using metal sulfate with high concentration (up to 5 M) as starting agents are attempted under carbon dioxides assisted conditions, and as-prepared materials also show improved performance.

  15. Facile fabrication of various zinc-nickel citrate microspheres and their transformation to ZnO-NiO hybrid microspheres with excellent lithium storage properties

    Science.gov (United States)

    Xie, Qingshui; Ma, Yating; Zeng, Deqian; Wang, Laisen; Yue, Guanghui; Peng, Dong-Liang

    2015-02-01

    Zinc-nickel citrate microspheres are prepared by a simple aging process of zinc citrate solid microspheres in nickel nitrate solution. As the concentration of nickel nitrate solution increases, the morphology of the produced zinc-nickel citrate evolves from solid, yolk-shell to hollow microspheres. The formation mechanism of different zinc-nickel citrate microspheres is discussed. After annealing treatment of the corresponding zinc-nickel citrate microspheres in air, three different ZnO-NiO hybrid architectures including solid, yolk-shell and hollow microspheres can be successfully fabricated. When applied as the anode materials for lithium ion batteries, ZnO-NiO hybrid yolk-shell microspheres demonstrate the best electrochemical properties than solid and hollow counterparts. After 200th cycles, ZnO-NiO hybrid yolk-shell microspheres deliver a high reversible capacity of 1176 mA h g-1. The unique yolk-shell configuration, the synergetic effect between ZnO and NiO and the catalytic effect of metal Ni generated by the reduction of NiO during discharging process are responsible for the excellent lithium storage properties of ZnO-NiO hybrid yolk-shell microspheres.

  16. Neutron Scattering Studies of Liquid on or Confined in Nano- and Mesoporous Carbons, Including Carbide-Derived Carbons

    Energy Technology Data Exchange (ETDEWEB)

    Wesolowski, David J [ORNL

    2014-07-01

    This project involved the synthesis of microporous graphitic-carbon powders with subnanometer average pore size, and very narrow pore size distributions, and the use of these materials in experimental studies of pore-fluid structure and dynamics. Samples of carbide-derived carbon powder, synthesized by extraction of the metal cations from TiC by a high temperature chlorination process, followed by high temperature vacuum annealing, were prepared by Ranjan Dash and his associates at CRADA partner Y-Carbon, Inc. The resulting material had average pore sizes ranging from 5 to 8 . These powders were used in two experiments conducted by researchers involved in the Energy Frontier Research Center Directed by David J. Wesolowski at ORNL, the Fluid Interface Reactions, Structures and Transport (FIRST) Center. FIRST-funded researchers at Drexel University collaborated with scientists at the Paul Scherrer Institute, Switzerland, to measure the expansion and contraction of the microporous carbon particles during charging and discharging of supercapactor electrodes composed of these particles (Hantell et al., 2011, Electrochemistry Communications, v. 13, pp. 1221-1224.) in an electrolyte composed of tetraethylammonium tetrafluoroborate dissolved in acetonitrile. In the second experiment, researchers at Oak Ridge National Laboratory and Drexel University conducted quasielastic neutron scattering studies of the diffusional dynamics of water imbibed into the micropores of the same material (Chathoth et al., 2011, EuroPhysics Journal, v. 95, pp. 56001/1-6). These studies helped to establish the role of pores approaching the size of the solvent and dissolved ions in altering diffusional dynamics, ion transport and physical response of conducting substrates to ion desolvation and entry into subnamometer pores.

  17. Capacitor with a composite carbon foam electrode

    Science.gov (United States)

    Mayer, Steven T.; Pekala, Richard W.; Kaschmitter, James L.

    1999-01-01

    Carbon aerogels used as a binder for granularized materials, including other forms of carbon and metal additives, are cast onto carbon or metal fiber substrates to form composite carbon thin film sheets. The thin film sheets are utilized in electrochemical energy storage applications, such as electrochemical double layer capacitors (aerocapacitors), lithium based battery insertion electrodes, fuel cell electrodes, and electrocapacitive deionization electrodes. The composite carbon foam may be formed by prior known processes, but with the solid partides being added during the liquid phase of the process, i.e. prior to gelation. The other forms of carbon may include carbon microspheres, carbon powder, carbon aerogel powder or particles, graphite carbons. Metal and/or carbon fibers may be added for increased conductivity. The choice of materials and fibers will depend on the electrolyte used and the relative trade off of system resistivity and power to system energy.

  18. Routing strategy including time and carbon dioxide emissions : effects on network performance

    NARCIS (Netherlands)

    Zhang, Fan; Chen, Y.; Goni Ros, B.; GAO, Jian; Knoop, V.L.

    2016-01-01

    Traffic congestion leads to delays and increased carbon dioxide (CO2) emissions. Traffic management measures such as providing information on environmental route costs have been proposed to mitigate congestion. Multi-criteria routing dynamic traffic assignment (MCR-DTA) models are needed to evaluate

  19. Sipandinolide: a butenolide including a novel type of carbon skeleton from Siparuna andina.

    Science.gov (United States)

    Jenett-Siems, K; Siems, K; Jakupovic, J; Solis, P N; Gupta, M P; Mockenhaupt, F P; Bienzle, U; Eich, E

    2000-05-01

    From a lipophilic extract of leaves of Siparuna andina (Monimiaceae), which exhibited antiplasmodial activity in vitro, two new compounds have been isolated: sipandinolide (1), a compound with a novel type of carbon skeleton and (-)-cis-3-acetoxy-4',5,7-trihydroxyflavanone (2). Their structures were established by spectroscopic methods; 2 showed moderate antiplasmodial activity whereas 1 was inactive.

  20. Coupled modeling of land hydrology–regional climate including human carbon emission and water exploitation

    Directory of Open Access Journals (Sweden)

    Zheng-Hui Xie

    2017-06-01

    Full Text Available Carbon emissions and water use are two major kinds of human activities. To reveal whether these two activities can modify the hydrological cycle and climate system in China, we conducted two sets of numerical experiments using regional climate model RegCM4. In the first experiment used to study the climatic responses to human carbon emissions, the model were configured over entire China because the impacts of carbon emissions can be detected across the whole country. Results from the first experiment revealed that near-surface air temperature may significantly increase from 2007 to 2059 at a rate exceeding 0.1 °C per decade in most areas across the country; southwestern and southeastern China also showed increasing trends in summer precipitation, with rates exceeding 10 mm per decade over the same period. In summer, only northern China showed an increasing trend of evapotranspiration, with increase rates ranging from 1 to 5 mm per decade; in winter, increase rates ranging from 1 to 5 mm per decade were observed in most regions. These effects are believed to be caused by global warming from human carbon emissions. In the second experiment used to study the effects of human water use, the model were configured over a limited region—Haihe River Basin in the northern China, because compared with the human carbon emissions, the effects of human water use are much more local and regional, and the Haihe River Basin is the most typical region in China that suffers from both intensive human groundwater exploitation and surface water diversion. We incorporated a scheme of human water regulation into RegCM4 and conducted the second experiment. Model outputs showed that the groundwater table severely declined by ∼10 m in 1971–2000 through human groundwater over-exploitation in the basin; in fact, current conditions are so extreme that even reducing the pumping rate by half cannot eliminate the groundwater depletion cones observed in the area

  1. Research progress of fabricating polyvinyl alcohol coating on plastic microsphere

    International Nuclear Information System (INIS)

    Su Lin; Chen Sufen; Liu Meifang; Zhang Zhanwen; Yao Hong; Li Bo; Liu Yiyang

    2012-01-01

    In the procedures of designing polystyrene-polyvinyl alcohol-CH (carbon and hydrogen elements) (PS-PVA-CH) triple-layer microspheres, there are many methods such as drop-tower technique, emulsion micro-encapsulation, dip (spin) coating, interfacial polycondensation, and spraying technique to prepare the PVA coating. Drop-tower technique, emulsion micro-encapsulation and dip (spin) coating are most-commonly used. The advantages, disadvantages and the research progress of the three methods are summarized in this paper. Emulsion micro-encapsulation is suitable for preparing double-layer microspheres of sizes smaller then 500 μm, with high survival ratio and good quality. However, the preparation process is easily influenced by artificial factors. Small-sized double-layer microspheres can also be prepared by the drop-tower technique, and the preparation period is short. But there are still some problems such as the difficulty in designing the droplet generator, uneven PVA coating and the difficulty in preparing large-sized microspheres. Dip (spin) coating technique can be used to prepare PS-PVA microspheres with sizes larger than 1000 μm, but the spread of PVA coating is affected by many factors in this method, and the prepared PVA coating is too thin and not uniform. (authors)

  2. Molecular Modeling of Aerospace Polymer Matrices Including Carbon Nanotube-Enhanced Epoxy

    Science.gov (United States)

    Radue, Matthew S.

    Carbon fiber (CF) composites are increasingly replacing metals used in major structural parts of aircraft, spacecraft, and automobiles. The current limitations of carbon fiber composites are addressed through computational material design by modeling the salient aerospace matrix materials. Molecular Dynamics (MD) models of epoxies with and without carbon nanotube (CNT) reinforcement and models of pure bismaleimides (BMIs) were developed to elucidate structure-property relationships for improved selection and tailoring of matrices. The influence of monomer functionality on the mechanical properties of epoxies is studied using the Reax Force Field (ReaxFF). From deformation simulations, the Young's modulus, yield point, and Poisson's ratio are calculated and analyzed. The results demonstrate an increase in stiffness and yield strength with increasing resin functionality. Comparison between the network structures of distinct epoxies is further advanced by the Monomeric Degree Index (MDI). Experimental validation demonstrates the MD results correctly predict the relationship in Young's moduli for all epoxies modeled. Therefore, the ReaxFF is confirmed to be a useful tool for studying the mechanical behavior of epoxies. While epoxies have been well-studied using MD, there has been no concerted effort to model cured BMI polymers due to the complexity of the network-forming reactions. A novel, adaptable crosslinking framework is developed for implementing 5 distinct cure reactions of Matrimid-5292 (a BMI resin) and investigating the network structure using MD simulations. The influence of different cure reactions and extent of curing are analyzed on the several thermo-mechanical properties such as mass density, glass transition temperature, coefficient of thermal expansion, elastic moduli, and thermal conductivity. The developed crosslinked models correctly predict experimentally observed trends for various properties. Finally, the epoxies modeled (di-, tri-, and tetra

  3. Slowing the rate of loss of mineral wetlands on human dominated landscapes - Diversification of farmers markets to include carbon (Invited)

    Science.gov (United States)

    Creed, I. F.; Badiou, P.; Lobb, D.

    2013-12-01

    Canada is the fourth-largest exporter of agriculture and agri-food products in the world (exports valued at 28B), but instability of agriculture markets can make it difficult for farmers to cope with variability, and new mechanisms are needed for farmers to achieve economic stability. Capitalizing on carbon markets will help farmers achieve environmentally sustainable economic performance. In order to have a viable carbon market, governments and industries need to know what the carbon capital is and what potential there is for growth, and farmers need financial incentives that will not only allow them to conserve existing wetlands but that will also enable them to restore wetlands while making a living. In southern Ontario, farmers' needs to maximize the return on investment on marginal lands have resulted in loss of 70-90% of wetlands, making this region one of the most threatened region in terms of wetland degradation and loss in Canada. Our project establishes the role that mineral wetlands have in the net carbon balance by contributing insight into the potential benefits to carbon management provided by wetland restoration efforts in these highly degraded landscapes. The goal was to establish the magnitude of carbon offsets that could be achieved through wetland conservation (securing existing carbon stocks) and restoration (creating new carbon stocks). The experimental design was to focus on (1) small (0.2-2.0 ha) and (2) isolated (no inflow or outflow) mineral wetlands with the greatest restoration potential that included (3) a range of restoration ages (drained (0 yr), 3 yr, 6 yr, 12 yr, 20 yr, 35 yr, intact marshes) to capture potential changes in rates of carbon sequestration with restoration age of wetland. From each wetland, wetland soil carbon pools samples were collected at four positions: centre of wetland (open-water); emergent vegetation zone; wet meadow zone where flooding often occurs (i.e., high water mark); and upland where flooding rarely

  4. Synthesis and characterization of magnesium gluconate contained poly(lactic-co-glycolic acid)/chitosan microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Shekh M. [Department of Chemical, Biological and Bioengineering, North Carolina A& T State University, 1601 East Market Street, Greensboro, NC 27411 (United States); NSF Engineering Research Center for Revolutionizing Metallic Biomaterials, North Carolina A& T State University, Greensboro, NC 27411 (United States); Mahoney, Christopher [Department of Bioengineering, University of Pittsburgh, 4200 Fifth Avenue, Pittsburgh, PA 15250 (United States); Sankar, Jagannathan [NSF Engineering Research Center for Revolutionizing Metallic Biomaterials, North Carolina A& T State University, Greensboro, NC 27411 (United States); Department of Mechanical Engineering, North Carolina A& T State University, 1601 East Market Street, Greensboro, NC 27411 (United States); Marra, Kacey G. [NSF Engineering Research Center for Revolutionizing Metallic Biomaterials, North Carolina A& T State University, Greensboro, NC 27411 (United States); Department of Bioengineering, University of Pittsburgh, 4200 Fifth Avenue, Pittsburgh, PA 15250 (United States); Department of Plastic Surgery, University of Pittsburgh, 200 Lothrop Street, Pittsburgh, PA 15250 (United States); McGowan Institute for Regenerative Medicine, University of Pittsburgh, 450 Technology Drive, Pittsburgh, PA 15250 (United States); Bhattarai, Narayan, E-mail: nbhattar@ncat.edu [Department of Chemical, Biological and Bioengineering, North Carolina A& T State University, 1601 East Market Street, Greensboro, NC 27411 (United States); NSF Engineering Research Center for Revolutionizing Metallic Biomaterials, North Carolina A& T State University, Greensboro, NC 27411 (United States)

    2016-01-15

    Graphical abstract: - Highlights: • Magnesium gluconate contained PLGA/chitosan microspheres were fabricated. • In vitro release of magnesium ions was performed using Xylidyl Blue assay. • Chitosan coated PLGA can significantly control the release of magnesium ions. • Cellular compatibility was tested using adipose-derived stem cells and PC12 cells. • The cells encounter acceptably low levels of damage in contact with microspheres. - Abstract: The goal of this study was to fabricate and investigate the chitosan coated poly(lactic-co-glycolic acid) (PLGA) microspheres for the development of controlled release magnesium delivery system. PLGA based microspheres are ideal vehicles for many controlled release drug delivery applications. Chitosan is a naturally occurring biodegradable and biocompatible polysaccharide, which can coat the surface of PLGA to alter the release of drugs. Magnesium gluconate (MgG) was encapsulated in the PLGA and PLGA/chitosan microspheres by utilizing the double emulsion solvent evaporation technique for controlled release study. The microspheres were tested with respect to several physicochemical and biological properties, including morphology, chemical structure, chitosan adsorption efficiency, magnesium encapsulation efficiency, in vitro release of magnesium ions, and cellular compatibility using both human adipose-derived stem cells (ASCs) and PC12 cells. Chitosan coated PLGA microspheres can significantly control the release of magnesium ions compared to uncoated PLGA microspheres. Both coated and uncoated microspheres showed good cellular compatibility.

  5. Review: microspheres for radioembolization therapy

    International Nuclear Information System (INIS)

    Zhao Mingqiang; Xu Shuhe

    2007-12-01

    Radioembolization of liver cancer has been proven to be an effective therapy in nuclear medicine. The yttrium-90 glass microspheres has been used to treat both primary and metastatic liver tumors in clinic which shown encouraging results. The preparation, stability, degradation and application for medical purpose of radioactive microspheres are reviewed. At first, the theory of radioem- bolization treating cancer is discussed; and then three major radiolabled micro- sphere materials are expounded: viz. glass, resin-based and polymer-based; Future improvements in the preparation and use of radioactive microspheres are prospected at last. (authors)

  6. Fresh meat packaging: consumer acceptance of modified atmosphere packaging including carbon monoxide.

    Science.gov (United States)

    Grebitus, Carola; Jensen, Helen H; Roosen, Jutta; Sebranek, Joseph G

    2013-01-01

    Consumers' perceptions and evaluations of meat quality attributes such as color and shelf life influence purchasing decisions, and these product attributes can be affected by the type of fresh meat packaging system. Modified atmosphere packaging (MAP) extends the shelf life of fresh meat and, with the inclusion of carbon monoxide (CO-MAP), achieves significant color stabilization. The objective of this study was to assess whether consumers would accept specific packaging technologies and what value consumers place on ground beef packaged under various atmospheres when their choices involved the attributes of color and shelf life. The study used nonhypothetical consumer choice experiments to determine the premiums that consumers are willing to pay for extended shelf life resulting from MAP and for the "cherry red" color in meat resulting from CO-MAP. The experimental design allowed determination of whether consumers would discount foods with MAP or CO-MAP when (i) they are given more detailed information about the technologies and (ii) they have different levels of individual knowledge and media exposure. The empirical analysis was conducted using multinomial logit models. Results indicate that consumers prefer an extension of shelf life as long as the applied technology is known and understood. Consumers had clear preferences for brighter (aerobic and CO) red color and were willing to pay $0.16/lb ($0.35/kg) for each level of change to the preferred color. More information on MAP for extending the shelf life and on CO-MAP for stabilizing color decreased consumers' willingness to pay. An increase in personal knowledge and media exposure influenced acceptance of CO-MAP negatively. The results provide quantitative measures of how packaging affects consumers' acceptance and willingness to pay for products. Such information can benefit food producers and retailers who make decisions about investing in new packaging methods.

  7. Yttrium-90 microsphere induced gastrointestinal tract ulceration

    Directory of Open Access Journals (Sweden)

    Rikabi Ali A

    2008-09-01

    Full Text Available Abstract Background Radiomicrosphere therapy (RT utilizing yttrium-90 (90Y microspheres has been shown to be an effective regional treatment for primary and secondary hepatic malignancies. We sought to determine a large academic institution's experience regarding the extent and frequency of gastrointestinal complications. Methods Between 2004 and 2007, 27 patients underwent RT for primary or secondary hepatic malignancies. Charts were subsequently reviewed to determine the incidence and severity of GI ulceration. Results Three patients presented with gastrointestinal bleeding and underwent upper endoscopy. Review of the pretreatment angiograms showed normal vascular anatomy in one patient, sclerosed hepatic vasculature in a patient who had undergone prior chemoembolization in a second, and an aberrant left hepatic artery in a third. None had undergone prophylactic gastroduodenal artery embolization. Endoscopic findings included erythema, mucosal erosions, and large gastric ulcers. Microspheres were visible on endoscopic biopsy. In two patients, gastric ulcers were persistent at the time of repeat endoscopy 1–4 months later despite proton pump inhibitor therapy. One elderly patient who refused surgical intervention died from recurrent hemorrhage. Conclusion Gastrointestinal ulceration is a known yet rarely reported complication of 90Y microsphere embolization with potentially life-threatening consequences. Once diagnosed, refractory ulcers should be considered for aggressive surgical management.

  8. Microspheres for the Growth of Silicon Nanowires via Vapor-Liquid-Solid Mechanism

    Directory of Open Access Journals (Sweden)

    Arancha Gómez-Martínez

    2014-01-01

    Full Text Available Silicon nanowires have been synthesized by a simple process using a suitable support containing silica and carbon microspheres. Nanowires were grown by thermal chemical vapor deposition via a vapor-liquid-solid mechanism with only the substrate as silicon source. The curved surface of the microsized spheres allows arranging the gold catalyst as nanoparticles with appropriate dimensions to catalyze the growth of nanowires. The resulting material is composed of the microspheres with the silicon nanowires attached on their surface.

  9. Characterization of Genotoxic Response to 15 Multiwalled Carbon Nanotubes with Variable Physicochemical Properties Including Surface Functionalizations in the FE1-Muta(TM) Mouse Lung Epithelial Cell Line

    DEFF Research Database (Denmark)

    Jackson, Petra; Kling, Kirsten; Jensen, Keld Alstrup

    2015-01-01

    Carbon nanotubes vary greatly in physicochemical properties. We compared cytotoxic and genotoxic response to 15 multiwalled carbon nanotubes (MWCNT) with varying physicochemical properties to identify drivers of toxic responses. The studied MWCNT included OECD Working Party on Manufactured Nanoma...

  10. Preparation and properties of BSA-loaded microspheres based on multi-(amino acid) copolymer for protein delivery

    Science.gov (United States)

    Chen, Xingtao; Lv, Guoyu; Zhang, Jue; Tang, Songchao; Yan, Yonggang; Wu, Zhaoying; Su, Jiacan; Wei, Jie

    2014-01-01

    A multi-(amino acid) copolymer (MAC) based on ω-aminocaproic acid, γ-aminobutyric acid, L-alanine, L-lysine, L-glutamate, and hydroxyproline was synthetized, and MAC microspheres encapsulating bovine serum albumin (BSA) were prepared by a double-emulsion solvent extraction method. The experimental results show that various preparation parameters including surfactant ratio of Tween 80 to Span 80, surfactant concentration, benzyl alcohol in the external water phase, and polymer concentration had obvious effects on the particle size, morphology, and encapsulation efficiency of the BSA-loaded microspheres. The sizes of BSA-loaded microspheres ranged from 60.2 μm to 79.7 μm, showing different degrees of porous structure. The encapsulation efficiency of BSA-loaded microspheres also ranged from 38.8% to 50.8%. BSA release from microspheres showed the classic biphasic profile, which was governed by diffusion and polymer erosion. The initial burst release of BSA from microspheres at the first week followed by constant slow release for the next 7 weeks were observed. BSA-loaded microspheres could degrade gradually in phosphate buffered saline buffer with pH value maintained at around 7.1 during 8 weeks incubation, suggesting that microsphere degradation did not cause a dramatic pH drop in phosphate buffered saline buffer because no acidic degradation products were released from the microspheres. Therefore, the MAC microspheres might have great potential as carriers for protein delivery. PMID:24855351

  11. microspheres-encapsulated vaccine preparation against ...

    African Journals Online (AJOL)

    PLGA) microspheres of coated in fish vaccine formulations. In this study, we prepared Pseudomonas bacteria widowed raise PLGA microspheres vaccine by double emulsion evaporation maltophilia. It was prepared to support the completion of the ...

  12. Gastroretentive Floating Microspheres of Silymarin: Preparation and ...

    African Journals Online (AJOL)

    Methods: Cellulose microspheres – formulated with hydroxylpropyl methylcellulose (HPMC) and ethyl cellulose (EC) – and Eudragit microspheres – formulated with Eudragit® S 100 (ES) and Eudragit® RL (ERL) - were prepared by an emulsion-solvent evaporation method. The floating microspheres were evaluated for flow ...

  13. Composite micro-sphere optical resonators for electric field measurement

    Science.gov (United States)

    Stubblefield, J.; Womack, D.; Ioppolo, T.; Ayaz, U.; Otugen, M. V.

    2012-02-01

    Polymer-based, multi-layered dielectric microspheres are investigated for high-resolution electric field sensing. The external electric field induces changes in the morphology of the spheres, leading to shifts in the whispering gallery modes (WGMs). Light from a distributed feedback (DFB) laser is sidecoupled into the microspheres using a tapered section of a single mode optical fiber to interrogate the optical modes. The base material of these multi-layered spheres is polydimethylsiloxane (PDMS). Three microsphere geometries are investigated: (1) cores comprised of a 60:1 volumetric ratio of PDMS-to-curing agent mixture that are mixed with varying amounts of barium titanate (BaTiO3) nano particles, (2) cores comprised of 60:1 PDMS that are coated with a thin layer of 60:1 PDMS that is mixed with varying amounts of barium titanate and (3) a composite Carbon Black-BaTiO3 prototype. The outermost layer for all sphere geometries is a thin coat of 60:1 PDMS which serves as the shell waveguide. Light from the tapered laser is coupled into this outermost shell that provides high optical quality factor WGM (Q ~ 106). The microspheres are poled for several hours at electric fields of ~ 1 MV/m to increase their sensitivity to electric field. Preliminary results show that electric fields of the order of 100 V/m can be detected using these composite micro-resonators.

  14. Formation of Tough Films by Evaporation of Water from Dispersions of Elastomer Microspheres Crosslinked with Rotaxane Supramolecules.

    Science.gov (United States)

    Hiroshige, Seina; Kureha, Takuma; Aoki, Daichi; Sawada, Jun; Aoki, Daisuke; Takata, Toshikazu; Suzuki, Daisuke

    2017-06-22

    Compared to rigid microspheres that consist, for example, of polystyrene or silica, soft and deformable elastomer microspheres can be used to generate colorless transparent films upon evaporating the solvent from microsphere-containing dispersions. To obtain tough films, a post-polymerization reaction to crosslink the microspheres is usually necessary, which requires extra additives during the drying process. This restriction renders this film-formation technology complex and rather unsuitable for applications in which impurities are undesirable. In the present study, it is demonstrated that tough elastomer microspheres that are crosslinked with rotaxanes can form tough bulk films upon evaporation of water from microsphere dispersions, so that post-polymerization reactions are not required. The results of this study should thus lead to new applications including coatings for biomaterials that need complete removal of all impurities from the materials prior to use. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Hierarchical ZnO-Ag-C composite porous microspheres with superior electrochemical properties as anode materials for lithium ion batteries.

    Science.gov (United States)

    Xie, Qingshui; Ma, Yating; Zeng, Deqian; Zhang, Xiaoqiang; Wang, Laisen; Yue, Guanghui; Peng, Dong-Liang

    2014-11-26

    Hierarchical ZnO-Ag-C composite porous microspheres are successfully synthesized by calcination of the preproduced zinc-silver citrate porous microspheres in argon. The carbon derives from the in situ carbonization of carboxylic acid groups in zinc-silver citrate during annealing treatment. The average particle size of ZnO-Ag-C composite porous microspheres is approximate 1.5 μm. When adopted as the electrode materials in lithium ion batteries, the obtained composite porous microspheres display high specific capacity, excellent cyclability, and good rate capability. A discharge capacity as high as 729 mA h g(-1) can be retained after 200 cycles at 100 mA g(-1). The excellent electrochemical properties of ZnO-Ag-C are ascribed to its unique hierarchical porous configuration as well as the modification of silver and carbon.

  16. Temperature influence in crystallinity of polymer microspheres

    International Nuclear Information System (INIS)

    Rezende, Cristiane de P.; Novack, Katia M.

    2011-01-01

    Drug delivery technology is evolving through the creation of new techniques of drug delivery effectively. The new methods used in drugs administration are based in microencapsulation process. Microsphere encapsulation modifies drug delivery bringing benefits and efficiency. In this work has been evaluated the influence of temperature in microspheres preparation. Microspheres were obtained by PMMA-co-PEG (COP) copolymer with indomethacin inserted in polymer matrix. Samples were characterized by SEM, DSC and XRD. SEM micrographs confirmed the formation of different sizes of microspheres and it was verified that higher temperatures make more crystalline microspheres. (author)

  17. Carbon Footprint of Inbound Tourism to Iceland: A Consumption-Based Life-Cycle Assessment including Direct and Indirect Emissions

    Directory of Open Access Journals (Sweden)

    Hannah Sharp

    2016-11-01

    Full Text Available The greenhouse gas (GHG emissions caused by tourism have been studied from several perspectives, but few studies exist that include all direct and indirect emissions, particularly those from aviation. In this study, an input/output-based hybrid life-cycle assessment (LCA method is developed to assess the consumption-based carbon footprint of the average tourist including direct and indirect emissions. The total inbound tourism-related GHG emissions are also calculated within a certain region. As a demonstration of the method, the full carbon footprint of an average tourist is assessed as well as the total GHG emissions induced by tourism to Iceland over the period of 2010–2015, with the presented approach applicable in other contexts as well. Iceland provides an interesting case due to three features: (1 the tourism sector in Iceland is the fastest-growing industry in the country with an annual growth rate of over 20% over the past five years; (2 almost all tourists arrive by air; and (3 the country has an almost emissions-free energy industry and an import-dominated economy, which emphasise the role of the indirect emissions. According to the assessment, the carbon footprint for the average tourist is 1.35 tons of CO2-eq, but ranges from 1.1 to 3.2 tons of CO2-eq depending on the distance travelled by air. Furthermore, this footprint is increasing due to the rise in average flight distances travelled to reach the country. The total GHG emissions caused by tourism in Iceland have tripled from approximately 600,000 tons of CO2-eq in 2010 to 1,800,000 tons in 2015. Aviation accounts for 50%–82% of this impact (depending on the flight distance underlining the importance of air travel, especially as tourism-related aviation is forecasted to grow significantly in the near future. From a method perspective, the carbon footprinting application presented in the study would seem to provide an efficient way to study both the direct and indirect

  18. Ultrathin 1T-phase MoS2 nanosheets decorated hollow carbon microspheres as highly efficient catalysts for solar energy harvesting and storage

    KAUST Repository

    Hsiao, Min-Chien

    2017-02-08

    The composite of MoS2 and hollow carbon sphere (MoS2@HCS) is prepared via a glucose-assisted one pot synthesis. The composite consists of hierarchical spheres with a diameter of 0.5–4 μm and these hollow spheres are decorated with a number of curled and interlaced MoS2 nanosheets. After the composite is subject to the lithium intercalation, the MoS2 is converted from 2H to 1T phase. In this current work, the activities of 1T-MoS2@HCS toward photocatalytic hydrogen evolution and the reduction of I3− in dye-sensitized solar cells (DSCs) are systemically investigated. When evaluated as the photocatalyst for hydrogen evolution, the amount of evolved hydrogen over 1T-MoS2@HCS can reach 143 μmol in 2 h, being 3.6 times higher than as-synthesized 2H-MoS2@HCS. Additionally, the 1T-MoS2@HCS can be employed as the counter electrode (CE) material in DSCs. The DSCs based on 1T-MoS2@HCS CE possesses the power conversion efficiency of 8.94%, being higher than that with 2H-MoS2@HCS CE (8.16%) and comparable to that with Pt CE (8.87%). Our study demonstrates that 1T-MoS2@HCS has a great potential as an inexpensive alternative to Pt catalysts.

  19. Porous chitosan microspheres containing zinc ion for enhanced thrombosis and hemostasis.

    Science.gov (United States)

    Pan, Meng; Tang, Zonghao; Tu, Jianbing; Wang, Zhengchao; Chen, Qinhui; Xiao, Rongdong; Liu, Haiqing

    2018-04-01

    Quick hemostats for non-lethal massive traumatic bleeding in battlefield and civilian accidents are important for reducing mortality and medical costs. Chitosan (CS) has been widely used as a clinic hemostat. To enhance its hemostatic efficiency, Zn 2+ in the form of zinc alginate (ZnAlg) was introduced to CS to make porous CS@ZnAlg microspheres with ZnAlg component on the surface. Such microspheres were prepared by successive steps of micro-emulsion, polyelectrolyte adhesion, and thermally induced phase separation. Their structure and hemostatic performance were analyzed by SEM, FT-IR, XPS and a series of in vitro hemostatic experiments including thromboelastography analysis. The composite microspheres had an outer and internal interconnected porous structure. Their size, surface area, and water absorption ratio were ca. 70μm, 48m 2 /g, and 1850%, respectively. Compared to the neat chitosan microspheres, the CS@ZnAlg microspheres showed shorter onset of clot formation, much faster in vitro and in vivo whole blood clotting, bigger clot, less blood loss, and shorter hemostatic time in the rat liver laceration and tail amputation models. The synergetic hemostatic effects from (1) the electrostatic attraction between chitosan component and red blood cells, (2) the activation of coagulation factor XII by Zn 2+ of zinc alginate component, and (3) physical blocking by microsphere matrix, contributed to the enhanced hemostatic performance of CS@ZnAlg microspheres. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. FEMIC (Fibromes Embolises aux MICrospheres calibrees): Uterine Fibroid Embolization using Tris-acryl Microspheres. A French Multicenter Study

    International Nuclear Information System (INIS)

    Joffre, Francis; Tubiana, Jean-Michel; Pelage, Jean-Pierre

    2004-01-01

    Purpose: A French multicenter registry was set up to confirm the safety and efficacy of large calibrated tris-acryl gelatin microspheres for embolization of symptomatic fibroids. Methods: Technical recommendations included embolization using large microspheres (>500 μm) with no secondary embolization agent. Postprocedural pain, clinical improvement and adverse events were prospectively evaluated during a follow-up period of at least 6 months.Results: Eighty-five women complaining of fibroid-related symptoms entered the study. In seven women, a secondary embolization agent was used in addition to microspheres. Complete resolution of menorrhagia was achieved in 84% of women at 24 months and significant uterine and fibroid volume reductions were noted after 6 months (37% and 73%, respectively). Three women experienced definitive amenorrhea (4%) and two women required hysteroscopic resection of a fibroid. Eight women were treated by hysterectomy because of treatment failure. In seven of these women, treatment failure was explained by an additional cause of symptoms including diffuse adenomyosis, endometrial hyperplasia or ovarian artery supply to the fibroids.Conclusion: Limited uterine artery embolization using large microspheres has good clinical success rate with low postprocedural pain and complications. Women can expect excellent midterm results with a high level of symptom control and significant fibroid volume reduction. Confidence in the end-point recommended here may require the experience of several cases

  1. Chitosan Microspheres as Radiolabeled Delivery Devices

    International Nuclear Information System (INIS)

    Permtermsin, Chalermsin; Ngamprayad, Tippanan; Phumkhem, Sudkanung; Srinuttrakul, Wannee; Kewsuwan, Prartana

    2007-08-01

    Full text: This study optimized conditions for preparing, characterizing, radiolabeled of chitosan microspheres and the biodistribution of 99mTc-Chitosan microspheres after intravenous administration. Particle size distribution of the microspheres was determined by light scattering. Zeta potential was studied by dynamic light scattering and electrophoresis technique. Biodistribution studies were performed by radiolabeling using 99mTc. The results shown that geometric mean diameter of the microspheres was found to be 77.26?1.96 ?m. Microsphere surface charge of chitosan microspheres was positive charge and zeta potential was 25.80 ? 0.46 mV. The labeling efficiency for this condition was more than 95% and under this condition was stable for at least 6 h. Radioactivity

  2. Storage stability of biodegradable polyethylene glycol microspheres

    Science.gov (United States)

    Jain, Era; Sheth, Saahil; Polito, Kristen; Sell, Scott A.; Zustiak, Silviya P.

    2017-10-01

    Degradable hydrogel microspheres are popular choices for multiple biomedical applications, including drug, protein, or cell carriers for minimally invasive delivery. Clinical transitioning of such new, sensitive pharmaceutical preparations requires investigation of storage methods that retain key properties for extended time. In this study, we sought to determine the influence of seven common storage conditions on the physical and mechanical properties of degradable polyethylene glycol (PEG) hydrogel microspheres: 25 °C, 4 °C, -80 °C, lyophilization/-20 °C, dimethyl sulfoxide/-80 °C, dimethyl sulfoxide/lyophilization/-20 °C, vacuum/-20 °C. We have outlined the storage conditions in detail and explained their effect on swelling ratio, stiffness and degradation rate post-storage. Additionally, we have implemented protein-loaded hydrogels to evaluate the effect of storage conditions on diffusivity as well as protein stability post-storage. We found that hydrogels could be stored short-term (1-4 d) under moist conditions (i.e. storage without drying) without a substantial loss of properties. For extended storage (7-28 d), they could be stored either at  -80 °C (moist condition) or vacuum drying (dry condition).

  3. Processing and Characterization of Sol-Gel Cerium Oxide Microspheres

    Energy Technology Data Exchange (ETDEWEB)

    McClure, Zachary D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Padilla Cintron, Cristina [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-09-27

    Of interest to space exploration and power generation, Radioisotope Thermoelectric Generators (RTGs) can provide long-term power to remote electronic systems without the need for refueling or replacement. Plutonium-238 (Pu-238) remains one of the more promising materials for thermoelectric power generation due to its high power density, long half-life, and low gamma emissions. Traditional methods for processing Pu-238 include ball milling irregular precipitated powders before pressing and sintering into a dense pellet. The resulting submicron particulates of Pu-238 quickly accumulate and contaminate glove boxes. An alternative and dust-free method for Pu-238 processing is internal gelation via sol-gel techniques. Sol-gel methodology creates monodisperse and uniform microspheres that can be packed and pressed into a pellet. For this study cerium oxide microspheres were produced as a surrogate to Pu-238. The similar electronic orbitals between cerium and plutonium make cerium an ideal choice for non-radioactive work. Before the microspheres can be sintered and pressed they must be washed to remove the processing oil and any unreacted substituents. An investigation was performed on the washing step to find an appropriate wash solution that reduced waste and flammable risk. Cerium oxide microspheres were processed, washed, and characterized to determine the effectiveness of the new wash solution.

  4. Filling Porous Microspheres With Magnetic Material

    Science.gov (United States)

    Chang, Manchium; Colvin, Michael S.

    1990-01-01

    New process produces magnetic microspheres with controllable sizes, compositions, and properties for use in medical diagnostic tests, biological research, and chemical processes. Paramagnetic microspheres also made with process. Porous plastic microspheres prepared by polymerization of monomer in diluent by cross-linking agent. When diluent removed, it leaves tiny pores throughout polymerized spheres. Size and distribution of pores determined by amount and type of diluent and cross-linking agent.

  5. Magnetoresponsive Photonic Microspheres with Structural Color Gradient.

    Science.gov (United States)

    Lee, Seung Yeol; Choi, Jongkook; Jeong, Jong-Ryul; Shin, Jung H; Kim, Shin-Hyun

    2017-04-01

    Photonic Janus particles are created by alternately sputtering silica and titania on microspheres in order to obtain a structural color gradient. In addition, the microspheres are rendered magnetoresponsive. The Janus microspheres with optical and magnetic anisotropy enable on-demand control over orientation and structural color through manipulation of an external magnetic field, thereby being useful as active color pigments for reflection-mode displays. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Aceclofenac microspheres: Quality by design approach

    Energy Technology Data Exchange (ETDEWEB)

    Deshmukh, Rameshwar K.; Naik, Jitendra B., E-mail: jitunaik@gmail.com

    2014-03-01

    The purpose of this study was to prepare polymeric microspheres containing aceclofenac by single emulsion [oil-in-water (o/w)] solvent evaporation method. Two biocompatible polymers, ethylcellulose, and Eudragit® RS100 were used in combination. Seven processing factors were investigated by Plackett–Burman design (PBD) in order to enhance the encapsulation efficiency of the microspheres. A Plackett–Burman design was employed by using the Design-Expert® software (Version-8.0.7.1). The resultant microspheres were characterized for their size, morphology, encapsulation efficiency, and drug release. Imaging of particles was performed by field emission scanning electron microscopy. Interaction between the drug and polymers were investigated by Fourier transform infrared (FTIR) spectroscopy, and X-ray powder diffractometry (XRPD). Graphical and mathematical analyses of the design showed that Eudragit® RS100, and polyvinyl alcohol (PVA) were significant negative effect on the encapsulation efficiency and identified as the significant factor determining the encapsulation efficiency of the microspheres. The low magnitudes of error and the significant values of R{sup 2} in the present investigation prove the high prognostic ability of the design. The microspheres showed high encapsulation efficiency (70.15% to 83.82%). The microspheres were found to be discrete, oval with smooth surface. The FTIR analysis confirmed the compatibility of aceclofenac with the polymers. The XRPD revealed the dispersion of drug within microspheres formulation. Perfect prolonged drug release profile over 12 h was achieved by a combination of ethylcellulose, and Eudragit® RS100 polymers. In conclusion, polymeric microspheres containing aceclofenac can be successfully prepared using the technique of experimental design, and these results helped in finding the optimum formulation variables for encapsulation efficiency of microspheres. - Graphical abstract: The polymeric microspheres

  7. Temporary ischaemia induced by degradable starch microspheres

    International Nuclear Information System (INIS)

    Lote, K.

    1981-01-01

    Possible thrombogenic effects of degradable starch microspheres were investigated. Controlled temporary small intestinal ischaemia was induced by injection into the superior mesenteric artery in cats. Arterial flow consistently recovered after ischaemia. No consumption of blood platelets, fibrinogen, or Factor VIII was observed. Aggregation of human platelets was not influenced by microsphere exposure, and platelet retention in starch microsphere columns was minimal. No thrombosis was detected in feline small intestinal vessels in vivo nor did starch surfaces induce adhesion or aggregation of human platelets in vitro. Thus, no evidence of thrombotic hazards was found by inducing temporary intestinal ischaemia by starch microspheres. (Auth.)

  8. Carbon Paste Electrodes Made from Different Carbonaceous Materials: Application in the Study of Antioxidants

    Science.gov (United States)

    Apetrei, Constantin; Apetrei, Irina Mirela; De Saja, Jose Antonio; Rodriguez-Mendez, Maria Luz

    2011-01-01

    This work describes the sensing properties of carbon paste electrodes (CPEs) prepared from three different types of carbonaceous materials: graphite, carbon microspheres and carbon nanotubes. The electrochemical responses towards antioxidants including vanillic acid, catechol, gallic acid, l-ascorbic acid and l-glutathione have been analyzed and compared. It has been demonstrated that the electrodes based on carbon microspheres show the best performances in terms of kinetics and stability, whereas G-CPEs presented the smallest detection limit for all the antioxidants analyzed. An array of electrodes has been constructed using the three types of electrodes. As demonstrated by means of Principal Component Analysis, the system is able to discriminate among antioxidants as a function of their chemical structure and reactivity. PMID:22319354

  9. The economics of including carbon sinks in climate change policy. Evaluating the carbon supply-curve through afforestation in Latin America

    NARCIS (Netherlands)

    Benìtez-Ponce, P.C.

    2003-01-01

    After the inclusion of carbon sinks in the Kyoto Protocol, greenhouse gas mitigation policies should account for abatement measurements in both the energy and forestry sectors. This report deals with the development of a methodology for estimating cost-curves of carbon sequestration with

  10. Highly efficient and porous TiO{sub 2}-coated Ag@Fe{sub 3}O{sub 4}@C-Au microspheres for degradation of organic pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Mao, E-mail: shenmao19820808@163.com; Chen, Suqing, E-mail: 465060605@qq.com; Jia, Wenping, E-mail: tzcjwp@tzc.edu.cn [Taizhou University, College of Pharmaceutical and Chemical Engineering (China); Fan, Guodong, E-mail: fangd@sust.edu.cn [Shan xi University of Science and Technology, Key Laboratory of Auxiliary Chemistry and Technology for Chemical Industry, Ministry of Education (China); Jin, Yanxian, E-mail: shirleyj@tzc.edu.cn; Liang, Huading, E-mail: shanjian8208@163.com [Taizhou University, College of Pharmaceutical and Chemical Engineering (China)

    2016-12-15

    In this paper, we reported a novel hierarchical porous Ag@Fe{sub 3}O{sub 4}@C-Au@TiO{sub 2} core@shell microspheres with a highly photocatalytic activity and magnetically separable properties. The synthesis method is included of a Fe{sub 3}O{sub 4} magnetic embedded Ag core (Ag@Fe{sub 3}O{sub 4}), an interlayer of carbon modified by PEI to form sufficient amounts of amine functional groups (Ag@Fe{sub 3}O{sub 4}@C-PEI), the grafting of Au nanoparticles on the surface of Ag@Fe{sub 3}O{sub 4}@C-PEI (Ag@Fe{sub 3}O{sub 4}@C-Au), and an ordered porous TiO{sub 2} structured shell. As an example of the applications, the photocatalytic activities of the samples were investigated by the reduction of Rhodamine B (RhB) under visible-light irradiation. The results show that the porous Ag@Fe{sub 3}O{sub 4}@C-Au@TiO{sub 2} core@shell microspheres display higher adsorption and photocatalytic activities compared to the pure porous TiO{sub 2} and Ag@Fe{sub 3}O{sub 4}@C@TiO{sub 2} microspheres, which are attributed to the local surface plasmon resonance (LSPR) by the Ag and Au nanoparticles and the high specific surface area.

  11. Patient Selection and Activity Planning Guide for Selective Internal Radiotherapy With Yttrium-90 Resin Microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Lau, Wan-Yee, E-mail: josephlau@surgery.cuhk.edu.hk [Faculty of Medicine, Chinese University of Hong Kong, Shatin, New Territories (Hong Kong); Kennedy, Andrew S. [Wake Radiology Oncology, Cary, NC (United States); Department of Biomedical Engineering, North Carolina State University, Raleigh, NC (United States); Kim, Yun Hwan [Department of Radiology, Anam Hospital, Korea University College of Medicine, Seoul (Korea, Republic of); Lai, Hee Kit [Nuclear Medicine and PET Centre, Mount Elizabeth Hospital, Singapore (Singapore); Lee, Rheun-Chuan [Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan (China); Leung, Thomas W.T. [Comprehensive Oncology Centre, Hong Kong Sanatorium and Hospital (Hong Kong); Liu, Ching-Sheng [Department of Nuclear Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (China); Salem, Riad [Division of Interventional Radiology, Northwestern University, Chicago, IL (United States); Sangro, Bruno [Liver Unit, Clinica Universitaria de Navarra and Centro de Investigacion Biomedica en Red de Enfermedades Hepaticas y Digestivas, Pamplona (Spain); Shuter, Borys [Department of Diagnostic Imaging, National University Hospital, Singapore (Singapore); Wang, Shih-Chang [Parker-Hughes Professor of Diagnostic Radiology, University of Sydney, Sydney, NSW (Australia)

    2012-01-01

    Purpose: Selective internal radiotherapy (SIRT) with yttrium-90 ({sup 90}Y) resin microspheres can improve the clinical outcomes for selected patients with inoperable liver cancer. This technique involves intra-arterial delivery of {beta}-emitting microspheres into hepatocellular carcinomas or liver metastases while sparing uninvolved structures. Its unique mode of action, including both {sup 90}Y brachytherapy and embolization of neoplastic microvasculature, necessitates activity planning methods specific to SIRT. Methods and Materials: A panel of clinicians experienced in {sup 90}Y resin microsphere SIRT was convened to integrate clinical experience with the published data to propose an activity planning pathway for radioembolization. Results: Accurate planning is essential to minimize potentially fatal sequelae such as radiation-induced liver disease while delivering tumoricidal {sup 90}Y activity. Planning methods have included empiric dosing according to degree of tumor involvement, empiric dosing adjusted for the body surface area, and partition model calculations using Medical Internal Radiation Dose principles. It has been recommended that at least two of these methods be compared when calculating the microsphere activity for each patient. Conclusions: Many factors inform {sup 90}Y resin microsphere SIRT activity planning, including the therapeutic intent, tissue and vasculature imaging, tumor and uninvolved liver characteristics, previous therapies, and localization of the microsphere infusion. The influence of each of these factors has been discussed.

  12. Preparation of hollow core/shell microspheres of hematite and its adsorption ability for samarium.

    Science.gov (United States)

    Yu, Sheng-Hui; Yao, Qi-Zhi; Zhou, Gen-Tao; Fu, Sheng-Quan

    2014-07-09

    Hollow core/shell hematite microspheres with diameter of ca. 1-2 μm have been successfully achieved by calcining the precursor composite microspheres of pyrite and polyvinylpyrrolidone (PVP) in air. The synthesized products were characterized by a wide range of techniques including powder X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), and Brunauer-Emmett-Teller (BET) gas sorptometry. Temperature- and time-dependent experiments unveil that the precursor pyrite-PVP composite microspheres finally transform into hollow core/shell hematite microspheres in air through a multistep process including the oxidation and sulfation of pyrite, combustion of PVP occluded in the precursor, desulfation, aggregation, and fusion of nanosized hematite as well as mass transportation from the interior to the exterior of the microspheres. The formation of the hollow core/shell microspheres dominantly depends on the calcination temperature under current experimental conditions, and the aggregation of hematite nanocrystals and the core shrinking during the oxidation of pyrite are responsible for the formation of the hollow structures. Moreover, the adsorption ability of the hematite for Sm(III) was also tested. The results exhibit that the hematite microspheres have good adsorption activity for trivalent samarium, and that its adsorption capacity strongly depends on the pH of the solution, and the maximum adsorption capacity for Sm(III) is 14.48 mg/g at neutral pH. As samarium is a typical member of the lanthanide series, our results suggest that the hollow hematite microspheres have potential application in removal of rare earth elements (REEs) entering the water environment.

  13. Microsphere fluoroimmunoassay for microorganisms: An update

    Energy Technology Data Exchange (ETDEWEB)

    Whitten, W.B.; Ramsey, J.M. [Oak Ridge National Lab., TN (United States); Bronk, B.V. [Edgewood Research, Development and Engineering Center, Aberdeen Proving Ground, MD (United States)

    1994-12-31

    Microspheres are used as labels in a fluorescence immunoassay for individual microorganisms. The diameter of a sphere that has reacted with microorganisms is determined from measurements of the optical resonance frequencies. The spheres have been coated with antibodies so that each microsphere diameter corresponds to a different species of microorganism. Further experiments on specificity and on optical resonance measurements are presented.

  14. Microsphere estimates of blood flow: Methodological considerations

    International Nuclear Information System (INIS)

    von Ritter, C.; Hinder, R.A.; Womack, W.; Bauerfeind, P.; Fimmel, C.J.; Kvietys, P.R.; Granger, D.N.; Blum, A.L.

    1988-01-01

    The microsphere technique is a standard method for measuring blood flow in experimental animals. Sporadic reports have appeared outlining the limitations of this method. In this study the authors have systematically assessed the effect of blood withdrawals for reference sampling, microsphere numbers, and anesthesia on blood flow estimates using radioactive microspheres in dogs. Experiments were performed on 18 conscious and 12 anesthetized dogs. Four blood flow estimates were performed over 120 min using 1 x 10 6 microspheres each time. The effects of excessive numbers of microspheres pentobarbital sodium anesthesia, and replacement of volume loss for reference samples with dextran 70 were assessed. In both conscious and anesthetized dogs a progressive decrease in gastric mucosal blood flow and cardiac output was observed over 120 min. This was also observed in the pancreas in conscious dogs. The major factor responsible for these changes was the volume loss due to the reference sample withdrawals. Replacement of the withdrawn blood with dextran 70 led to stable blood flows to all organs. The injection of excessive numbers of microspheres did not modify hemodynamics to a greater extent than did the injection of 4 million microspheres. Anesthesia exerted no influence on blood flow other than raising coronary flow. The authors conclude that although blood flow to the gastric mucosa and the pancreas is sensitive to the minor hemodynamic changes associated with the microsphere technique, replacement of volume loss for reference samples ensures stable blood flow to all organs over a 120-min period

  15. Preparation of microstructured hydroxyapatite microspheres using ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Hydroxyapatite (HAP) microspheres with peculiar spheres-in-sphere morphology were prepared by using oil-in-water emulsions and solvent evaporation technique. Ethylene vinyl acetate co-polymer (EVA) was used as the binder material. Preparation of HAP/EVA microspheres was followed by the thermal de-.

  16. Biodegradable poly (lactic acid) microspheres containing total ...

    Indian Academy of Sciences (India)

    The fabrication of biodegradable poly(lactic acid) (PLA) microspheres containing total alkaloids of Caulis sinomenii was investigated. The formation, diameter, morphology and properties of the microspheres were characterized using Fourier transform infrared spectroscopy (FT–IR), laser particle size analyser and scanning ...

  17. Microencapsulation and microspheres for food applications

    NARCIS (Netherlands)

    Sagis, L.M.C.

    2015-01-01

    This book provides an update on the latest developments, challenges, and opportunities in the highly expanding field of microencapsulation and microspheres for food applications, examining the various types of microspheres and microcapsules essential to those who need to develop stable and

  18. U3O8 microspheres sintering kinetics

    International Nuclear Information System (INIS)

    Godoy, A.L.E.

    1986-01-01

    U 3 O 8 microspheres sintering kinetics was determined using a hot-stage optical microscopy apparatus, able to reach temperature up to 1350 0 C in controlled atmospheres. The sintered material had its microstructure analysed by optical and electron microscopy. The microspheres were characterized initialy utilizing X-ray diffractometry and thermogravimetry. The equation which describes the microspheres shrinkage in function of the time was obtained using finite difference analysis X-ray diffractometry indicated hexagonal structure for the microspheres main starting material, ammonium diuranate thermogravimetric analysis showed reduction of this material to U 3 O 8 at 600 0 C. Ceramography results showed 5 hours sintered microspheres grain sizes G vary with the temperature. Sintered U 3 O 8 micrographs compared with published results for UO 2 , indicate similar homogeneity microstructural characteristics and suggest the processed micorspheres to be potentially useful as nuclear fuels. (Author) [pt

  19. Magnetic susceptibility characterisation of superparamagnetic microspheres

    Science.gov (United States)

    Grob, David Tim; Wise, Naomi; Oduwole, Olayinka; Sheard, Steve

    2018-04-01

    The separation of magnetic materials in microsystems using magnetophoresis has increased in popularity. The wide variety and availability of magnetic beads has fuelled this drive. It is important to know the magnetic characteristics of the microspheres in order to accurately use them in separation processes integrated on a lab-on-a-chip device. To investigate the magnetic susceptibility of magnetic microspheres, the magnetic responsiveness of three types of Dynabeads microspheres were tested using two different approaches. The magnetophoretic mobility of individual microspheres is studied using a particle tracking system and the magnetization of each type of Dynabeads microsphere is measured using SQUID relaxometry. The magnetic beads' susceptibility is obtained at four different applied magnetic fields in the range of 38-70 mT for both the mobility and SQUID measurements. The susceptibility values in both approaches show a consistent magnetic field dependence.

  20. Microspheres and Nanotechnology for Drug Delivery.

    Science.gov (United States)

    Jóhannesson, Gauti; Stefánsson, Einar; Loftsson, Thorsteinn

    2016-01-01

    Ocular drug delivery to the posterior segment of the eye can be accomplished by invasive drug injections into different tissues of the eye and noninvasive topical treatment. Invasive treatment involves the risks of surgical trauma and infection, and conventional topical treatments are ineffective in delivering drugs to the posterior segment of the eye. In recent years, nanotechnology has become an ever-increasing part of ocular drug delivery. In the following, we briefly review microspheres and nanotechnology for drug delivery to the eye, including different forms of nanotechnology such as nanoparticles, microparticles, liposomes, microemulsions and micromachines. The permeation barriers and anatomical considerations linked to ocular drug delivery are discussed and a theoretical overview on drug delivery through biological membranes is given. Finally, in vitro, in vivo and human studies of x03B3;-cyclodextrin nanoparticle eyedrop suspensions are discussed as an example of nanotechnology used for drug delivery to the eye. © 2016 S. Karger AG, Basel.

  1. Including sorption to black carbon in modelling bioaccumulation of polycyclic aromatic hydrocarbons: Uncertainty analysis and comparison with field data

    NARCIS (Netherlands)

    Hauck, M.; Hendriks, A.J.; Huijbregts, M.J.A.; Koelmans, A.A.; Heuvel-Greve, van den M.J.; Moermond, C.T.A.; Veltman, K.; Vethaak, A.D.

    2007-01-01

    Model estimations of bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) have been higher than field or laboratory data. This has been explained by strong sorption to black carbon (BC). In this paper, eight previously published bioaccumulation datasets were reinterpreted in terms of

  2. Chitosan microspheres in novel drug delivery systems.

    Science.gov (United States)

    Mitra, Analava; Dey, Baishakhi

    2011-07-01

    The main aim in the drug therapy of any disease is to attain the desired therapeutic concentration of the drug in plasma or at the site of action and maintain it for the entire duration of treatment. A drug on being used in conventional dosage forms leads to unavoidable fluctuations in the drug concentration leading to under medication or overmedication and increased frequency of dose administration as well as poor patient compliance. To minimize drug degradation and loss, to prevent harmful side effects and to increase drug bioavailability various drug delivery and drug targeting systems are currently under development. Handling the treatment of severe disease conditions has necessitated the development of innovative ideas to modify drug delivery techniques. Drug targeting means delivery of the drug-loaded system to the site of interest. Drug carrier systems include polymers, micelles, microcapsules, liposomes and lipoproteins to name some. Different polymer carriers exert different effects on drug delivery. Synthetic polymers are usually non-biocompatible, non-biodegradable and expensive. Natural polymers such as chitin and chitosan are devoid of such problems. Chitosan comes from the deacetylation of chitin, a natural biopolymer originating from crustacean shells. Chitosan is a biocompatible, biodegradable, and nontoxic natural polymer with excellent film-forming ability. Being of cationic character, chitosan is able to react with polyanions giving rise to polyelectrolyte complexes. Hence chitosan has become a promising natural polymer for the preparation of microspheres/nanospheres and microcapsules. The techniques employed to microencapsulate with chitosan include ionotropic gelation, spray drying, emulsion phase separation, simple and complex coacervation. This review focuses on the preparation, characterization of chitosan microspheres and their role in novel drug delivery systems.

  3. Graphene Aerogel Templated Fabrication of Phase Change Microspheres as Thermal Buffers in Microelectronic Devices.

    Science.gov (United States)

    Wang, Xuchun; Li, Guangyong; Hong, Guo; Guo, Qiang; Zhang, Xuetong

    2017-11-29

    Phase change materials, changing from solid to liquid and vice versa, are capable of storing and releasing a large amount of thermal energy during the phase change, and thus hold promise for numerous applications including thermal protection of electronic devices. Shaping these materials into microspheres for additional fascinating properties is efficient but challenging. In this regard, a novel phase change microsphere with the design for electrical-regulation and thermal storage/release properties was fabricated via the combination of monodispersed graphene aerogel microsphere (GAM) and phase change paraffin. A programmable method, i.e., coupling ink jetting-liquid marbling-supercritical drying (ILS) techniques, was demonstrated to produce monodispersed graphene aerogel microspheres (GAMs) with precise size-control. The resulting GAMs showed ultralow density, low electrical resistance, and high specific surface area with only ca. 5% diameter variation coefficient, and exhibited promising performance in smart switches. The phase change microspheres were obtained by capillary filling of phase change paraffin inside the GAMs and exhibited excellent properties, such as low electrical resistance, high latent heat, well sphericity, and thermal buffering. Assembling the phase change microsphere into the microcircuit, we found that this tiny device was quite sensitive and could respond to heat as low as 0.027 J.

  4. Synthesis and Characterization of Gd₂O₃ Hollow Microspheres Using a Template-Directed Method.

    Science.gov (United States)

    Jiang, Xueliang; Yu, Lu; Yao, Chu; Zhang, Fuqing; Zhang, Jiao; Li, Chenjian

    2016-04-28

    Uniform rare-earth gadolinium oxide (Gd₂O₃) hollow microspheres, as formed through a urea-assisted homogenous precipitation process using carbon spheres as a template and a subsequent heat treatment, were characterized by using X-ray diffraction, Fourier transformed infared spectroscopy, thermogravimetry, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and Brunauer-Emmett-Tellet surface area measurement. The results indicate that the final products can be indexed to a cubic Gd₂O₃ phase with high purity and have a uniform morphology at 500 nm in diameter and 20 nm in shell thickness. The as-synthesized Gd₂O₃ hollow microspheres exhibited a superior photooxidation activity to that of Gd₂O₃ powder and an effect similar to P25, significantly broadening the potential of Gd₂O₃ hollow microspheres for many practical applications.

  5. Synthesis and Characterization of Gd2O3 Hollow Microspheres Using a Template-Directed Method

    Science.gov (United States)

    Jiang, Xueliang; Yu, Lu; Yao, Chu; Zhang, Fuqing; Zhang, Jiao; Li, Chenjian

    2016-01-01

    Uniform rare-earth gadolinium oxide (Gd2O3) hollow microspheres, as formed through a urea-assisted homogenous precipitation process using carbon spheres as a template and a subsequent heat treatment, were characterized by using X-ray diffraction, Fourier transformed infared spectroscopy, thermogravimetry, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and Brunauer-Emmett-Tellet surface area measurement. The results indicate that the final products can be indexed to a cubic Gd2O3 phase with high purity and have a uniform morphology at 500 nm in diameter and 20 nm in shell thickness. The as-synthesized Gd2O3 hollow microspheres exhibited a superior photooxidation activity to that of Gd2O3 powder and an effect similar to P25, significantly broadening the potential of Gd2O3 hollow microspheres for many practical applications. PMID:28773446

  6. Synthesis and Characterization of Gd2O3 Hollow Microspheres Using a Template-Directed Method

    Directory of Open Access Journals (Sweden)

    Xueliang Jiang

    2016-04-01

    Full Text Available Uniform rare-earth gadolinium oxide (Gd2O3 hollow microspheres, as formed through a urea-assisted homogenous precipitation process using carbon spheres as a template and a subsequent heat treatment, were characterized by using X-ray diffraction, Fourier transformed infared spectroscopy, thermogravimetry, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and Brunauer-Emmett-Tellet surface area measurement. The results indicate that the final products can be indexed to a cubic Gd2O3 phase with high purity and have a uniform morphology at 500 nm in diameter and 20 nm in shell thickness. The as-synthesized Gd2O3 hollow microspheres exhibited a superior photooxidation activity to that of Gd2O3 powder and an effect similar to P25, significantly broadening the potential of Gd2O3 hollow microspheres for many practical applications.

  7. Radiation-curing of acrylate composites including carbon fibres: A customized surface modification for improving mechanical performances

    International Nuclear Information System (INIS)

    Martin, Arnaud; Pietras-Ozga, Dorota; Ponsaud, Philippe; Kowandy, Christelle; Barczak, Mariusz; Defoort, Brigitte; Coqueret, Xavier

    2014-01-01

    The lower transverse mechanical properties of radiation-cured acrylate-based composites reinforced with carbon-fibre with respect to the thermosettable analogues was investigated from the viewpoint of chemical interactions at the interface between the matrix and the carbon material. XPS analysis of representative commercial carbon fibres revealed the presence of a significant amount of chemical functions potentially exerting an adverse effect on the initiation and propagation of the free radical polymerization initiated under high energy radiation. The EB-induced polymerization of n-butyl acrylate as a simple model monomer was conducted in the presence of various aromatic additives exhibiting a strong inhibiting effect, whereas thiols efficiently sensitize the initiation mechanism and undergo transfer reactions. A method based on the surface modification of sized fibres by thiomalic acid is proposed for overcoming the localized inhibition phenomenon and for improving the mechanical properties of the resulting acrylate-based composites. - Highlights: • Surface functions of C-fibres are analyzed for their effect on radical reaction. • Irradiation of nBu-acrylate in presence of aromatic additives reveals inhibition. • Thiol groups sensitize the radiation-initiated polymerization of nBu-acrylate. • Modification of C-fibres with thiomalic acid enhances composite properties

  8. Solid evacuated microspheres of hydrogen

    Science.gov (United States)

    Turnbull, Robert J.; Foster, Christopher A.; Hendricks, Charles D.

    1982-01-01

    A method is provided for producing solid, evacuated microspheres comprised of hydrogen. The spheres are produced by forming a jet of liquid hydrogen and exciting mechanical waves on the jet of appropriate frequency so that the jet breaks up into drops with a bubble formed in each drop by cavitation. The drops are exposed to a pressure less than the vapor pressure of the liquid hydrogen so that the bubble which is formed within each drop expands. The drops which contain bubbles are exposed to an environment having a pressure just below the triple point of liquid hydrogen and they thereby freeze giving solid, evacuated spheres of hydrogen.

  9. Nuclear fuel microsphere gamma analyzer

    International Nuclear Information System (INIS)

    Valentine, K.H.; Long, E.L. Jr.; Willey, M.G.

    1977-01-01

    A gamma analyzer system is provided for the analysis of nuclear fuel microspheres and other radioactive particles. The system consists of an analysis turntable with means for loading, in sequence, a plurality of stations within the turntable; a gamma ray detector for determining the spectrum of a sample in one section; means for analyzing the spectrum; and a receiver turntable to collect the analyzed material in stations according to the spectrum analysis. Accordingly, particles may be sorted according to their quality; e.g., fuel particles with fractured coatings may be separated from those that are not fractured, or according to other properties. 4 claims, 3 figures

  10. Facile fabrication of porous ZnO microspheres by thermal treatment of ZnS microspheres.

    Science.gov (United States)

    Wu, Xiao; Li, KunWei; Wang, Hao

    2010-02-15

    Porous ZnO microspheres with an average size of around 500 nm had been synthesized by thermal treatment of ZnS microspheres in an air atmosphere. The ZnS spheres had been synthesized at a low temperature of 100 degrees C by using L-cysteine (an ordinary amino acid) as a sulfur source with the assist of gelatin. By combining the results of X-ray diffraction (XRD), transmission electron microscope (TEM), field-emission scanning electron microscopy (FE-SEM), and Fourier transformation infrared spectra (FTIR), a structural and morphological characterization of the products was performed. The photocatalytic activity of ZnS microspheres and porous ZnO microspheres have been tested by degradation of Rhodamine-B (RB) under UV light, indicating that the porous ZnO microspheres showed enhanced photocatalytic performance compared to ZnS microspheres and commercial Degussa P25 TiO(2).

  11. Aceclofenac microspheres: quality by design approach.

    Science.gov (United States)

    Deshmukh, Rameshwar K; Naik, Jitendra B

    2014-03-01

    The purpose of this study was to prepare polymeric microspheres containing aceclofenac by single emulsion [oil-in-water (o/w)] solvent evaporation method. Two biocompatible polymers, ethylcellulose, and Eudragit® RS100 were used in combination. Seven processing factors were investigated by Plackett-Burman design (PBD) in order to enhance the encapsulation efficiency of the microspheres. A Plackett-Burman design was employed by using the Design-Expert® software (Version-8.0.7.1). The resultant microspheres were characterized for their size, morphology, encapsulation efficiency, and drug release. Imaging of particles was performed by field emission scanning electron microscopy. Interaction between the drug and polymers were investigated by Fourier transform infrared (FTIR) spectroscopy, and X-ray powder diffractometry (XRPD). Graphical and mathematical analyses of the design showed that Eudragit® RS100, and polyvinyl alcohol (PVA) were significant negative effect on the encapsulation efficiency and identified as the significant factor determining the encapsulation efficiency of the microspheres. The low magnitudes of error and the significant values of R(2) in the present investigation prove the high prognostic ability of the design. The microspheres showed high encapsulation efficiency (70.15% to 83.82%). The microspheres were found to be discrete, oval with smooth surface. The FTIR analysis confirmed the compatibility of aceclofenac with the polymers. The XRPD revealed the dispersion of drug within microspheres formulation. Perfect prolonged drug release profile over 12h was achieved by a combination of ethylcellulose, and Eudragit® RS100 polymers. In conclusion, polymeric microspheres containing aceclofenac can be successfully prepared using the technique of experimental design, and these results helped in finding the optimum formulation variables for encapsulation efficiency of microspheres. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Seeing is believing, PLGA microsphere degradation revealed in PLGA microsphere/PVA hydrogel composites.

    Science.gov (United States)

    Gu, Bing; Sun, Xuanhao; Papadimitrakopoulos, Fotios; Burgess, Diane J

    2016-04-28

    The aim of this study was to understand the polymer degradation and drug release mechanism from PLGA microspheres embedded in a PVA hydrogel. Two types of microspheres were prepared with different molecular weight PLGA polymers (approximately 25 and 7 kDa) to achieve different drug release profiles, with a 9-day lag phase and without a lag phase, respectively. The kinetics of water uptake into the microspheres coincided with the drug release profiles for both formulations. For the 25 kDa microspheres, minimal water uptake was observed in the early part of the lag phase followed by substantial water uptake at the later stages and in the drug release phase. For the 7 kDa microspheres, water uptake occurred simultaneously with drug release. Water uptake was approximately 2-3 times that of the initial microsphere weight for both formulations. The internal structure of the PLGA microspheres was evaluated using low temperature scanning electron microscopy (cryo-SEM). Burst drug release occurred followed by pore forming from the exterior to the core of both microspheres. A well-defined hydrogel/microsphere interface was observed. For the 25 kDa microspheres, internal pore formation and swelling occurred before the second drug release phase. The surface layer of the microspheres remained intact whereas swelling, and degradation of the core continued throughout the drug release period. In addition, microsphere swelling reduced glucose transport through the coatings in PBS media and this was considered to be a as a consequence of the increased thickness of the coatings. The combination of the swelling and microdialysis results provides a fresh understanding on the competing processes affecting molecular transport of bioanalytes (i.e. glucose) through these composite coatings during prolonged exposure in PBS. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Challenges for INAA in studies of materials from advanced material research including rare earth concentrates and carbon based ceramics

    International Nuclear Information System (INIS)

    Bode, P.; Van Meerten, Th.G.

    2000-01-01

    Rare-earth elements are increasingly applied in advanced materials to be used, e.g., in electronic industry, automobile catalysts, or lamps and optical devices. Trace element analysis of these materials might be an interesting niche for NAA because of the intrinsic high accuracy of this technique, and the shortage of matrix matching reference materials with other methods for elemental analysis. The carbon composite materials form another category of advanced materials, where sometimes a very high degree of purity is required. Also for these materials, NAA has favorable analytical characteristics. Examples are given of the use of NAA in the analysis of both categories of materials. (author)

  14. Progress in Preparation of Monodisperse Polymer Microspheres

    Science.gov (United States)

    Zhang, Hongyan

    2017-12-01

    The monodisperse crosslinked polymer microspheres have attracted much attention because of their superior thermal and solvent resistance, mechanical strength, surface activity and adsorption properties. They are of wide prospects for using in many fields such as biomedicine, electronic science, information technology, analytical chemistry, standard measurement and environment protection etc. Functional polymer microspheres prepared by different methods have the outstanding surface property, quantum size effect and good potential future in applications with its designable structure, controlled size and large ratio of surface to volume. Scholars of all over the world have focused on this hot topic. The preparation method and research progress in functional polymer microspheres are addressed in the paper.

  15. Synthesis of CaCO3nano- and micro-particles by dry ice carbonation.

    Science.gov (United States)

    Donnelly, F C; Purcell-Milton, F; Framont, V; Cleary, O; Dunne, P W; Gun'ko, Y K

    2017-06-16

    Here we report a new low temperature dry ice carbonation approach for the synthesis of carbonate-based nano- and micro-particulate materials, which enables the preparation of monodispersed calcium carbonate nanoparticles and microspheres with very high purity phases.

  16. Development of a sol-gel process by internal gelation for production of U O2 microspheres

    International Nuclear Information System (INIS)

    Poramatikul, N.

    1986-01-01

    Preparation of U O 2 -microspheres by sol-gel processes were studied. The internal gelation process was selected to produce the microspheres by using the capillary nozzle of various sizes, exerting pressure on syringe both by weight and N 2 -gas pressure for the drop formation. The conditions for increasing the rate of formation and sizes of microspheres were also studied together with washing, drying and sintering of the microspheres. The optimum condition for microspheres formation were as follows: broth concentration 1.25 mole U/liter, free-forming by capillary of 0.45-0.9 mm. diameter, purging with 0.2-0.9 l/min N 2 -gas, column diameter of 2.5 cm. and 200 cm. height filled with trichloroethylene mixed with 0.02% Span 80 and heat to 68-70 degree C gave the microspheres of 300-1000 micro m diameter which collected at the bottom of the column. After washing drying and sintering in Ar-4% H 2 at 1200 degree C the carbon content of the product were reduced from 10% to 0.1% and the ratio of O to U were 2.0-2.05, the maximum density were 80% Theoretical Density

  17. PLGA/alginate composite microspheres for hydrophilic protein delivery

    International Nuclear Information System (INIS)

    Zhai, Peng; Chen, X.B.; Schreyer, David J.

    2015-01-01

    Poly(lactic-co-glycolic acid) (PLGA) microspheres and PLGA/alginate composite microspheres were prepared by a novel double emulsion and solvent evaporation technique and loaded with bovine serum albumin (BSA) or rabbit anti-laminin antibody protein. The addition of alginate and the use of a surfactant during microsphere preparation increased the encapsulation efficiency and reduced the initial burst release of hydrophilic BSA. Confocal laser scanning microcopy (CLSM) of BSA-loaded PLGA/alginate composite microspheres showed that PLGA, alginate, and BSA were distributed throughout the depths of microspheres; no core/shell structure was observed. Scanning electron microscopy revealed that PLGA microspheres erode and degrade more quickly than PLGA/alginate composite microspheres. When loaded with anti-laminin antibody, the function of released antibody was well preserved in both PLGA and PLGA/alginate composite microspheres. The biocompatibility of PLGA and PLGA/alginate microspheres were examined using four types of cultured cell lines, representing different tissue types. Cell survival was variably affected by the inclusion of alginate in composite microspheres, possibly due to the sensitivity of different cell types to excess calcium that may be released from the calcium cross-linked alginate. - Highlights: • A double emulsion technique is used to prepare protein-loaded PLGA or PLGA/alginate microspheres. • PLGA, alginate and protein are distributed evenly within microsphere structure. • Addition of alginate improves loading efficiency and slows degradation and protein release. • PLGA/alginate microspheres have favorable biocompatibility

  18. PLGA/alginate composite microspheres for hydrophilic protein delivery

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Peng [Department of Anatomy and Cell Biology, University of Saskatchewan, S7N5E5 (Canada); Division of Biomedical Engineering, University of Saskatchewan, S7N5A9 (Canada); Chen, X.B. [Department of Mechanical Engineering, University of Saskatchewan, S7N5A9 (Canada); Division of Biomedical Engineering, University of Saskatchewan, S7N5A9 (Canada); Schreyer, David J., E-mail: david.schreyer@usask.ca [Department of Anatomy and Cell Biology, University of Saskatchewan, S7N5E5 (Canada); Division of Biomedical Engineering, University of Saskatchewan, S7N5A9 (Canada)

    2015-11-01

    Poly(lactic-co-glycolic acid) (PLGA) microspheres and PLGA/alginate composite microspheres were prepared by a novel double emulsion and solvent evaporation technique and loaded with bovine serum albumin (BSA) or rabbit anti-laminin antibody protein. The addition of alginate and the use of a surfactant during microsphere preparation increased the encapsulation efficiency and reduced the initial burst release of hydrophilic BSA. Confocal laser scanning microcopy (CLSM) of BSA-loaded PLGA/alginate composite microspheres showed that PLGA, alginate, and BSA were distributed throughout the depths of microspheres; no core/shell structure was observed. Scanning electron microscopy revealed that PLGA microspheres erode and degrade more quickly than PLGA/alginate composite microspheres. When loaded with anti-laminin antibody, the function of released antibody was well preserved in both PLGA and PLGA/alginate composite microspheres. The biocompatibility of PLGA and PLGA/alginate microspheres were examined using four types of cultured cell lines, representing different tissue types. Cell survival was variably affected by the inclusion of alginate in composite microspheres, possibly due to the sensitivity of different cell types to excess calcium that may be released from the calcium cross-linked alginate. - Highlights: • A double emulsion technique is used to prepare protein-loaded PLGA or PLGA/alginate microspheres. • PLGA, alginate and protein are distributed evenly within microsphere structure. • Addition of alginate improves loading efficiency and slows degradation and protein release. • PLGA/alginate microspheres have favorable biocompatibility.

  19. Fossil energy consumption and greenhouse gas emissions, including soil carbon effects, of producing agriculture and forestry feedstocks

    Science.gov (United States)

    Christina E. Canter; Zhangcai Qin; Hao Cai; Jennifer B. Dunn; Michael Wang; D. Andrew Scott

    2017-01-01

    The GHG emissions and fossil energy consumption associated with producing potential biomass sup­ply in the select BT16 scenarios include emissions and energy consumption from biomass production, harvest/collection, transport, and pre-processing activities to the reactor throat. Emissions associated with energy, fertilizers, and...

  20. In vitro Evaluation of Nateglinide-Loaded Microspheres Formulated ...

    African Journals Online (AJOL)

    Purpose: To formulate and evaluate sustained release microspheres of nateglinide (NTG) for enhanced patient compliance. Methods: Nateglinide microspheres were prepared with varying proportions of biodegradable polymers (olibanum gum and guar gum) by calcium chloride/sodium alginate ionic gelation method.

  1. The effect of some processing conditions on the characteristics of biodegradable microspheres obtained by an emulsion solvent evaporation process

    Directory of Open Access Journals (Sweden)

    J. L. Maia

    2004-01-01

    Full Text Available Unloaded microspheres were prepared from polyhydroxybutyrate (PHB and polyhydroxybutyrate-co-valerate (PHB-HV polymers using an oil-in-water emulsion solvent evaporation method. The study was conducted to evaluate how the polymer and some process parameters affect properties of the final microspheres such as particle size, superficial area, zeta potential, surface morphology and microsphere degradation. The variables included surfactant concentration in the emulsion water phase and solvent composition. From the results, it was found that the parameters affecting microsphere size the most were surfactant concentration in the emulsion water phase and solvent composition. Properties such as zeta potential, surface area and surface morphology remained pratically unchanged over the range of the processing conditions studied here.

  2. Preparation and in vitro/in vivo characterization of curcumin microspheres intended to treat colon cancer

    Directory of Open Access Journals (Sweden)

    M Madhavi

    2012-01-01

    Full Text Available Objective: The objective of the present investigation was to prepare colon targeted curcumin microspheres using Eudragit S100 and evaluate the same for in vitro/in vivo properties. Materials and Methods: A "O/O solvent evaporation" technique was used in the preparation of microspheres. The influence of various process variables including stirring speed, drug:polymer ratio and percentage of emulsifier on the fabrication were investigated and the formulation was optimized. Prepared microspheres were evaluated for in vitro and in vivo properties. Surface morphology, particle size, percentage drug entrapment, percentage yield, drug polymer interaction, in vitro drug release in simulated gastrointestinal transit conditions and stability were the in vitro parameters investigated. Using an optimized formulation, drug release into the systemic circulation and organ distribution were investigated as in vivo parameters. In vivo parameters were estimated in male albino rats. Results: Curcumin microspheres of Eudragit S100 were successfully prepared using o/o solvent evaporation method. Microspheres prepared using 1:2 drug:polymer ratio, with a stirring speed of 1000 rpm, and using 1.0% w/v concentration of emulsifying agent was selected as an optimized formulation. The release studies with optimized formulation demonstrated that aqueous solubility of curcumin was enhanced by 8 times with the formulation. FTIR studies demonstrated no change in drug characteristics upon microsphere fabrication. The enhancement in solubility is thus due to the increase in the surface area of the drug substance and not due to a change of drug to a different physical state. This was further confirmed by scanning electron microsphere pictures. Drug release followed Korsmeyer and Peppas release model. Accelerated stability studies indicated that the drug is stable in the formulation for a period of atleast 14 weeks at room temperature. In vivo studies demonstrated a sustained

  3. Preparation and Characterization of Sugar Cane Wax Microspheres ...

    African Journals Online (AJOL)

    ... and characterize indomethacin (IM) microspheres prepared with sugar cane wax microsperes. Methods: Microspheres were prepared by melt-emulsified dispersion and cooling-induced solidification method. The microspheres were characterized by scanning electron microscopy (SEM) and differntial scanning calorimetry ...

  4. Preparation of polymer microspheres by radiation-induced polymerization

    International Nuclear Information System (INIS)

    Naka, Y.; Yamamoto, Y.; Yoshida, Y.; Tagawa, S.

    1995-01-01

    Cross-liking monomer, diethylene glycol dimethacrylate gives microspheres from organic solution by radiation-induced polymerization. /One of the remarkable result is that the number of the microspheres is not changing during the polymerization. Ethyl methacrylate, maleic anhydride, styrene and acrylamide are used as comonomers. These comonomers give the microspheres in the range of 0 to 0.4 as mol fractions. (author)

  5. Microsphere-aided optical microscopy and its applications for super-resolution imaging

    Science.gov (United States)

    Upputuri, Paul Kumar; Pramanik, Manojit

    2017-12-01

    The spatial resolution of a standard optical microscope (SOM) is limited by diffraction. In visible spectrum, SOM can provide ∼ 200 nm resolution. To break the diffraction limit several approaches were developed including scanning near field microscopy, metamaterial super-lenses, nanoscale solid immersion lenses, super-oscillatory lenses, confocal fluorescence microscopy, techniques that exploit non-linear response of fluorophores like stimulated emission depletion microscopy, stochastic optical reconstruction microscopy, etc. Recently, photonic nanojet generated by a dielectric microsphere was used to break the diffraction limit. The microsphere-approach is simple, cost-effective and can be implemented under a standard microscope, hence it has gained enormous attention for super-resolution imaging. In this article, we briefly review the microsphere approach and its applications for super-resolution imaging in various optical imaging modalities.

  6. Synthesis and Characterization of Gd2O3 Hollow Microspheres Using a Template-Directed Method

    OpenAIRE

    Xueliang Jiang; Lu Yu; Chu Yao; Fuqing Zhang; Jiao Zhang; Chenjian Li

    2016-01-01

    Uniform rare-earth gadolinium oxide (Gd2O3) hollow microspheres, as formed through a urea-assisted homogenous precipitation process using carbon spheres as a template and a subsequent heat treatment, were characterized by using X-ray diffraction, Fourier transformed infared spectroscopy, thermogravimetry, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and Brunauer-Emmett-Tellet surface area measurement. The results indicate that the final prod...

  7. Electrostatic Assembly of Sandwich-like Ag-C@ZnO-C@Ag-C Hybrid Hollow Microspheres with Excellent High-Rate Lithium Storage Properties.

    Science.gov (United States)

    Xie, Qingshui; Ma, Yating; Wang, Xuanpeng; Zeng, Deqian; Wang, Laisen; Mai, Liqiang; Peng, Dong-Liang

    2016-01-26

    Herein, we introduce a facile electrostatic attraction approach to produce zinc-silver citrate hollow microspheres, followed by thermal heating treatment in argon to ingeniously synthesize sandwich-like Ag-C@ZnO-C@Ag-C hybrid hollow microspheres. The 3D carbon conductive framework in the hybrids derives from the in situ carbonation of carboxylate acid groups in zinc-silver citrate hollow microspheres during heating treatment, and the continuous and homogeneous Ag nanoparticles on the outer and inner surfaces of hybrid hollow microspheres endow the shells with the sandwiched configuration (Ag-C@ZnO-C@Ag-C). When applied as the anode materials for lithium ion batteries, the fabricated hybrid hollow microspheres with sandwich-like shells reveal a very large reversible capacity of 1670 mAh g(-1) after 200 cycles at a current density of 0.2 A g(-1). Even at the very large current densities of 1.6 and 10.0 A g(-1), the high specific capacities of about 1063 and 526 mAh g(-1) can be retained, respectively. The greatly enhanced electrochemical properties of Ag-C@ZnO-C@Ag-C hybrid microspheres are attributed to their special structural features such as the hollow structures, the sandwich-like shells, and the nanometer-sized building blocks.

  8. Green and facile fabrication of hollow porous MnO/C microspheres from microalgaes for lithium-ion batteries.

    Science.gov (United States)

    Xia, Yang; Xiao, Zhen; Dou, Xiao; Huang, Hui; Lu, Xianghong; Yan, Rongjun; Gan, Yongping; Zhu, Wenjun; Tu, Jiangping; Zhang, Wenkui; Tao, Xinyong

    2013-08-27

    Hollow porous micro/nanostructures with high surface area and shell permeability have attracted tremendous attention. Particularly, the synthesis and structural tailoring of diverse hollow porous materials is regarded as a crucial step toward the realization of high-performance electrode materials, which has several advantages including a large contact area with electrolyte, a superior structural stability, and a short transport path for Li(+) ions. Meanwhile, owing to the inexpensive, abundant, environmentally benign, and renewable biological resources provided by nature, great efforts have been devoted to understand and practice the biotemplating technology, which has been considered as an effective strategy to achieve morphology-controllable materials with structural specialty, complexity, and related unique properties. Herein, we are inspired by the natural microalgae with its special features (easy availability, biological activity, and carbon sources) to develop a green and facile biotemplating method to fabricate monodisperse MnO/C microspheres for lithium-ion batteries. Due to the unique hollow porous structure in which MnO nanoparticles were tightly embedded into a porous carbon matrix and form a penetrative shell, MnO/C microspheres exhibited high reversible specific capacity of 700 mAh g(-1) at 0.1 A g(-1), excellent cycling stability with 94% capacity retention, and enhanced rate performance of 230 mAh g(-1) at 3 A g(-1). This green, sustainable, and economical strategy will extend the scope of biotemplating synthesis for exploring other functional materials in various structure-dependent applications such as catalysis, gas sensing, and energy storage.

  9. Seeing is believing, PLGA microsphere degradation revealed in PLGA microsphere/PVA hydrogel composites

    OpenAIRE

    Gu, Bing; Sun, Xuanhao; Papadimitrakopoulos, Fotios; Burgess, Diane J.

    2016-01-01

    The aim of this study was to understand the polymer degradation and drug release mechanism from PLGA microspheres embedded in a PVA hydrogel. Two types of microspheres were prepared with different molecular weight PLGA polymers (approximately 25 and 7 kDa) to achieve different drug release profiles, with a 9-day lag phase and without a lag phase, respectively. The kinetics of water uptake into the microspheres coincided with the drug release profiles for both formulations. For the 25 kDa micr...

  10. Biosensing by WGM Microspherical Resonators

    Directory of Open Access Journals (Sweden)

    Giancarlo C. Righini

    2016-06-01

    Full Text Available Whispering gallery mode (WGM microresonators, thanks to their unique properties, have allowed researchers to achieve important results in both fundamental research and engineering applications. Among the various geometries, microspheres are the simplest 3D WGM resonators; the total optical loss in such resonators can be extremely low, and the resulting extraordinarily high Q values of 108–109 lead to high energy density, narrow resonant-wavelength lines and a lengthy cavity ringdown. They can also be coated in order to better control their properties or to increase their functionality. Their very high sensitivity to changes in the surrounding medium has been exploited for several sensing applications: protein adsorption, trace gas detection, impurity detection in liquids, structural health monitoring of composite materials, detection of electric fields, pressure sensing, and so on. In the present paper, after a general introduction to WGM resonators, attention is focused on spherical microresonators, either in bulk or in bubble format, to their fabrication, characterization and functionalization. The state of the art in the area of biosensing is presented, and the perspectives of further developments are discussed.

  11. Localized drugs delivery hydroxyapatite microspheres for osteoporosis therapy

    Science.gov (United States)

    Lee, J. H.; Ko, I. H.; Jeon, S.-H.; Chae, J. H.; Lee, E. J.; Chang, J. H.

    2011-10-01

    This study describes the preparation of hydroxyapatite microspheres for local drugs delivery. The formation of the hydroxyapatite microspheres was initiated by enzymatic decomposition of urea and accomplished by emulsification process (water-in-oil). The microspheres obtained were sintered at 500°C. Scanning electron microscope (SEM) indicated that the microspheres have various porous with random size, which maximizes the surface area. Cytotoxicity was not observed after sintering. Osteoporosis drugs, alendronate and BMP-2, were loaded into HAp microspheres and the releases of both molecules showed sustained releasing profiles.

  12. CHARACTERIZATION OF MICRO/NANO POROUS HOLLOW GLASS MICROSPHERES FABRICATED THROUGH VARIOUS CHEMICAL ETCHING PROCESSE FOR USE IN SMART COATINGS

    Directory of Open Access Journals (Sweden)

    T. Ebrahimi Sadrabadi

    2016-12-01

    Full Text Available Porous hollow glass microspheres have many uses, including encapsulation of active materials. In this paper a fast and facile method for fabricating porous hollow glass-microspheres was demonstrated by etching them using dilute hydrofluoric acid. Then, a highly reactive amine was infiltrated into the etched glass microspheres. Scanning electron microscopy was conducted for the hollow glass microspheres prior and post etching process. With regards to the porous hollow glass spherical sample, the spherical nature, morphology, pore diameter and the porosity were studied using scanning electron microscopy. Formation of the intact hollow glass microspheres with an open through wall porosities following phase separation and etching of the boron oxide rich phase was demonstrated using reciprocating shaker as the most suitable agitation method. The BET results indicated that the surface of the porous microspheres contained nano-pores. It is believed that the simplicity of the reported fabrication technique of micro/nano porous structure has the potential to scaling up for large scale production

  13. Facile synthesis of biphasic calcium phosphate microspheres with engineered surface topography for controlled delivery of drugs and proteins.

    Science.gov (United States)

    Zarkesh, Ibrahim; Ghanian, Mohammad Hossein; Azami, Mahmoud; Bagheri, Fatemeh; Baharvand, Hossein; Mohammadi, Javad; Eslaminejad, Mohamadreza Baghaban

    2017-09-01

    Biphasic calcium phosphate (BCP) microspheres are of great interest due to their high stability and osteoinductive properties at specific compositions. However, the need for optimal performance at a unique composition limits their flexibility for tuning drug release by modulation of bulk properties and presents the question of engineering surface topography as an alternative. It is necessary to have a facile method to control surface topography at a defined bulk composition. Here, we have produced BCP microspheres with different surface topographies that have the capability to be used as tunable drug release systems. We synthesized calcium deficient hydroxyapatite (CDHA) microparticles by precipitating calcium and phosphate ions onto ethylenediaminetetraacetic acid (EDTA) templates. The morphology and surface topography of CDHA microparticles were controlled using process parameters, which governed nucleation and growth. These parameters included template concentration, heat rate, and stirring speed. Under low heat rate and static conditions, we could obtain spherical microparticles with long and short nanosheets on their surfaces at low and high EDTA concentrations, respectively. These nanostructured microspheres were subsequently crystallized by thermal treatment to produce EDTA-free BCP microspheres with intact morphology. These biocompatible BCP microspheres were highly effective in loading and prolonged release of both small molecule [dexamethasone (Dex)] and protein [bovine serum albumin (BSA)] models. This strategy has enabled us to control the surface topography of BCP microspheres at defined compositions and holds tremendous promise for drug delivery and tissue engineering applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Reverse micelle-based microencapsulation of oxytetracycline hydrochloride into poly-d,l-lactide-co-glycolide microspheres.

    Science.gov (United States)

    Kim, Hyunjoo; Lee, Beom-Jin; Sah, Hongkee

    2007-02-01

    The objectives of this study were to solubilize oxytetracycline hydrochloride (HCl) in reverse micelles to prepare poly-d,l-lactide-co-glycolide (PLGA) microspheres and to explore parameters affecting its encapsulation efficiency. Oxytetracycline HCl was dissolved in the reverse micelles consisting of cetyltrimethylammonium bromide, water, and ethyl formate. A PLGA polymer was then dissolved in the reverse micellar solution, and a modified solvent quenching procedure was carried out to prepare PLGA microspheres. Encapsulation efficiencies of oxytetracycline HCl ranged from 2.3 +/- 0.2 to 24.9 +/- 4.6%, depending on experimental conditions. Important parameters affecting its encapsulation efficiency included the amounts of water used to prepare the reverse micelles and PLGA polymer. With regard to microsphere morphology, the reverse micellar process produced the microspheres with smooth and pore-free surfaces. In particular, their internal matrices did not possess hollow cavities that were frequently observed when a typical double emulsion technique was used to make microspheres. In summary, it was possible to encapsulate oxytetracycline HCl into PLGA microspheres via the ethyl formate-based reverse micellar technique. We also anticipate that the use of ethyl formate could avoid environmental and human toxicity issues associated with methylene chloride.

  15. A microsphere suspension model of metamaterial fluids

    Directory of Open Access Journals (Sweden)

    Qian Duan

    2017-05-01

    Full Text Available Drawing an analogy to the liquid phase of natural materials, we theoretically propose a microsphere suspension model to realize a metamaterial fluid with artificial electromagnetic indexes. By immersing high-ε, micrometer-sized dielectric spheres in a low-ε insulating oil, the structured fluid exhibits liquid-like properties from dispersing phase as well as the isotropic negative electromagnetic parameters caused by Mie resonances from dispersed microspheres. The work presented here will benefit the development of structured fluids toward metamaterials.

  16. Preparation of biodegradable porous poly(butylene succinate microspheres

    Directory of Open Access Journals (Sweden)

    Pepić Dragana

    2008-01-01

    Full Text Available The aim of this study was to determine the optimal conditions for the fabrication of porous microspheres based on poly(butylene succinate, PBS. The biodegradable non-porous PBS microspheres were prepared by the oil-in-water (o/w emulsion solvent evaporation method using poly(vinyl alcohol, PVA, as the surfactant. Fabrication conditions, such as stirring rate, organic/aqueous ratio, PBS concentration and surfactant (PVA concentration, which have an important influence on both the particle size and the morphology of the microspheres, were varied. Scanning electron microscopy, SEM, observations confirmed the size, size distribution and surface morphology of the microspheres. The optimal conditions for the preparation of the non-porous microspheres were found to be: concentration the PBS solution, 10 mass%; PVA concentration, 1 mass%; the organic/ aqueous ratio CHCl3/H2O = 1/20 and stirring rate 800 rpm. Porous PBS microspheres were fabricated under the optimal conditions using various amounts of hexane and poly(ethylene oxide, PEO, as porogens. The influence of the amount of porogen on the pore size and the particle size was investigated using SEM and the apparent density. The microspheres exhibited various porosities and the pore sizes. The average particle size of the microspheres with PEO as the porogen was from 100 to 122μm and that of the microspheres with hexane as the porogen was from 87 to 97μm. The apparent density of the porous microspheres with PEO as the porogen, from 0.16 to 0.23 g/cm3, was much smaller than the non-porous microspheres, 0.40 g/cm3. In the in vitro degradation experiments, the porous microspheres were incubated in phosphate buffer solution (pH 7 at 37°C. After incubating for one month, the microspheres showed significant extent of the hydrolytic degradation of the porous PBS microspheres.

  17. Mechanisms of in vivo release of triamcinolone acetonide from PLGA microspheres.

    Science.gov (United States)

    Doty, Amy C; Weinstein, David G; Hirota, Keiji; Olsen, Karl F; Ackermann, Rose; Wang, Yan; Choi, Stephanie; Schwendeman, Steven P

    2017-06-28

    Little is known about the underlying effects controlling in vitro-in vivo correlations (IVIVCs) for biodegradable controlled release microspheres. Most reports of IVIVCs that exist are empirical in nature, typically based on a mathematical relationship between in vitro and in vivo drug release, with the latter often estimated by deconvolution of pharmacokinetic data. In order to improve the ability of in vitro release tests to predict microsphere behavior in vivo and develop more meaningful IVIVCs, the in vivo release mechanisms need to be characterized. Here, two poly(lactic-co-glycolic acid) (PLGA) microsphere formulations encapsulating the model steroid triamcinolone acetonide (Tr-A) were implanted subcutaneously in rats by using a validated cage model, allowing for free fluid and cellular exchange and microsphere retrieval during release. Release kinetics, as well as mechanistic indicators of release such as hydrolysis and mass loss, was measured by direct analysis of the recovered microspheres. Release of Tr-A from both formulations was greatly accelerated in vivo compared to in vitro using agitated phosphate buffered saline +0.02% Tween 80 pH7.4, including rate of PLGA hydrolysis, mass loss and water uptake. Both microsphere formulations exhibited erosion-controlled release in vitro, indicated by similar polymer mass loss kinetics, but only one of the formulations (low molecular weight, free acid terminated) exhibited the same mechanism in vivo. The in vivo release of Tr-A from microspheres made of a higher molecular weight, ester end-capped PLGA displayed an osmotically induced/pore diffusion mechanism based on confocal micrographs of percolating pores in the polymer, not previously observed in vitro. This research indicates the need to fully understand the in vivo environment and how it causes drug release from biodegradable microspheres. This understanding can then be applied to develop in vitro release tests which better mimic this environment and cause

  18. Nickel metal with various morphologies: synthesis and performances for catalytic carbon dioxide reforming with methane.

    Science.gov (United States)

    Teabpinyok, Nopporn; Samingprai, Sutheerawat; Chareonpanich, Metta

    2012-12-01

    In this research, nickel metal of three different morphologies including nanostar, icosahedra, and microsphere structures were synthesized. It was found nanostar nickel revealed the Ni(111) crystallographic plane with particle size in the range of 150-200 nm and BET surface area of 13 m2/g. The icosahedra nickel also showed the Ni(111) crystallographic plane with larger particle size (300-400 nm) and BET surface area of 20 m2/g, whereas microsphere nickel exhibited the relatively large cluster size (approximately 3 microm) and BET surface area (114 m2/g) as a result of an aggregation of Ni(101) nanoplates. The obtained nickel catalysts were tested for the activity in carbon dioxide reforming with methane. Based on the similar specific surface area of catalysts, nanostar nickel showed the highest carbon dioxide and methane conversions due to its crystallographic structure. At 700 degrees C, nanostar nickel catalyst exhibited the highest carbon dioxide and methane conversions of 17.6 and 10.5 times higher than those of microsphere nickel catalyst, respectively.

  19. Structuring of diamond films using microsphere lithography

    Czech Academy of Sciences Publication Activity Database

    Domonkos, Mária; Ižák, Tibor; Štolcová, L.; Proška, J.; Demo, Pavel; Kromka, Alexander

    2014-01-01

    Roč. 54, č. 5 (2014), s. 320-324 ISSN 1210-2709 R&D Projects: GA ČR(CZ) GBP108/12/G108 Institutional support: RVO:68378271 Keywords : nanostructuring * diamond thin films * polystyrene microspheres * reactive ion etching * scanning electron microscopy Subject RIV: BM - Solid Matter Physics ; Magnetism

  20. Synthesis of polycaprolactone/nano hydroxyapatite microspheres

    International Nuclear Information System (INIS)

    Sampaio, Greyce Y.H.; Souza, Mairly K. da S.; Melo, Rafaela Q. da C.; Carrodeguas, Raul G.; Fook, Marcus V.L.

    2015-01-01

    Polycaprolactone(PCL)/nano hydroxyapatite(nHA) microspheres are advantageous material for manufacturing tridimensional scaffolds and formulating drug delivery systems for bone regeneration. The work was aimed to study the effect of processing variables on the properties of PCL/nHA microspheres. nHA was produced by precipitation method and was obtained calcium deficient nanoparticles consisted of nanorods (∼47 nm x ∼8 nm), according to the results of XRD, FTIR and TEM. PCL/nHA microspheres was produced by solid-in-oil-in-water emulsion solvent evaporation method. The variables studied were concentration of PCL (5,7.5 and 10 % w/v), nHA addition (17, 23 and 28.5% m/m) and surface treatment of nHA with stearic acid (AE). PCL/nHA microspheres were characterized by XRD, FTIR, SEM and TGA. The best result was obtained with a PCL concentration of 10% (w/v) and 23 % (m/m) of modified nHA. Solid PCL/nHA particles ranging 30-70 μm and containing 14 % of nHA dispersed in the polymer matrix were obtained, with agglomerates of nHA raging 5 -15 μm. These results suggest the promising use of this material in bone regeneration devices. (author)

  1. MICROSPHERE SIZE INFLUENCES THE FOREIGN BODY REACTION

    NARCIS (Netherlands)

    Zandstra, J.; Hiemstra, C.; Petersen, A. H.; Zuidema, J.; van Beuge, M. M.; Rodriguez, S.; Lathuile, A. A. R.; Veldhuis, G. J.; Steendam, R.; Bank, R. A.; Popa, E. R.

    2014-01-01

    Biodegradable poly-(DL-lactide-co-glycolide) (PLGA) microspheres (MSP) are attractive candidate vehicles for site-specific or systemic sustained release of therapeutic compounds. This release may be altered by the host's foreign body reaction (FBR), which is dependent on the characteristics of the

  2. Preparation of microstructured hydroxyapatite microspheres using ...

    Indian Academy of Sciences (India)

    Unknown

    Indian Academy of Sciences. 383. Preparation of microstructured hydroxyapatite microspheres using oil in water emulsions. T S PRADEESH, M C SUNNY, H K VARMA and P RAMESH*. Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology,. Thiruvananthapuram 695 012, India.

  3. Method and apparatus for producing microspherical particles

    International Nuclear Information System (INIS)

    Egli, W.; Bailey, W.H.; Leary, D.F.; Lansley, R.J.

    1979-01-01

    This invention relates generally to a method and apparatus for producing microspherical particles and more particularly to a method and apparatus which are particularly useful in connection with the sol-gel process for the production of nuclear fuel kernels. (U.K.)

  4. Beat-Frequency/Microsphere Medical Ultrasonic Imaging

    Science.gov (United States)

    Yost, William T.; Cantrell, John H.; Pretlow, Robert A., III

    1995-01-01

    Medical ultrasonic imaging system designed to provide quantitative data on various flows of blood in chambers, blood vessels, muscles, and tissues of heart. Sensitive enough to yield readings on flows of blood in heart even when microspheres used as ultrasonic contrast agents injected far from heart and diluted by circulation of blood elsewhere in body.

  5. Evaluation of Controlled Release Theophylline Microspheres ...

    African Journals Online (AJOL)

    Erah

    The microencapsulation technique by solvent evaporation process has been extensively studied in recent years for the preparation of microspheres. This is a complex process and requires strict control of several processing parameters such as rate of solvent evaporation, stirring rate, viscosity of polymeric phase, drug ...

  6. Encapsulated PDMS microspheres with reactive handles

    DEFF Research Database (Denmark)

    Gonzalez, Lidia; Ma, Baoguang; Li, Li

    2014-01-01

    Cured poly(dimethyl siloxane) microspheres are prepared by an emulsion polymerization reaction of silicone droplets in a continuous aqueous phase. The commonly used PDMS elastomer, Sylgard 184 from Dow Corning, is used as the dispersed phase. PDMS is polymerized and cross-linked by reacting vinyl...

  7. Assembly of functional gold nanoparticle on silica microsphere.

    Science.gov (United States)

    Wang, Hsuan-Lan; Lee, Fu-Cheng; Tang, Tse-Yu; Zhou, Chenguang; Tsai, De-Hao

    2016-05-01

    We demonstrate a controlled synthesis of silica microsphere with the surface-decorated functional gold nanoparticles. Surface of silica microsphere was modified by 3-aminopropypltriethoxysilane and 3-aminopropyldimethylethoxysilane to generate a positive electric field, by which the gold nanoparticles with the negative charges (unconjugated, thiolated polyethylene glycol functionalized with the traceable packing density and conformation) were able to be attracted to the silica microsphere. Results show that both the molecular conjugation on gold nanoparticle and the uniformity in the amino-silanization of silica microsphere influenced the loading and the homogeneity of gold nanoparticles on silica microsphere. The 3-aminopropyldimethylethoxysilane-functionalized silica microsphere provided an uniform field to attract gold nanoparticles. Increasing the ethanol content in aminosilane solution significantly improved the homogeneity and the loading of gold nanoparticles on the surface of silica microsphere. For the gold nanoparticle, increasing the molecular mass of polyethylene glycol yielded a greater homogeneity but a lower loading on silica microsphere. Bovine serum albumin induced the desorption of gold nanoparticles from silica microsphere, where the extent of desorption was suppressed by the presence of high-molecular mass polyethylene glycol on gold nanoparticles. This work provides the fundamental understanding for the synthesis of gold nanoparticle-silica microsphere constructs useful to the applications in chemo-radioactive therapeutics. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Characterization of genotoxic response to 15 multiwalled carbon nanotubes with variable physicochemical properties including surface functionalizations in the FE1-Muta(TM) mouse lung epithelial cell line.

    Science.gov (United States)

    Jackson, Petra; Kling, Kirsten; Jensen, Keld Alstrup; Clausen, Per Axel; Madsen, Anne Mette; Wallin, Håkan; Vogel, Ulla

    2015-03-01

    Carbon nanotubes vary greatly in physicochemical properties. We compared cytotoxic and genotoxic response to 15 multiwalled carbon nanotubes (MWCNT) with varying physicochemical properties to identify drivers of toxic responses. The studied MWCNT included OECD Working Party on Manufactured Nanomaterials (WPMN) (NM-401, NM-402, and NM-403), materials (NRCWE-026 and MWCNT-XNRI-7), and three sets of surface-modified MWCNT grouped by physical characteristics (thin, thick, and short I-III, respectively). Each Groups I-III included pristine, hydroxylated and carboxylated MWCNT. Group III also included an amino-functionalized MWCNT. The level of surface functionalization of the MWCNT was low. The level and type of elemental impurities of the MWCNT varied by <2% of the weight, with exceptions. Based on dynamic light scattering data, the MWCNT were well-dispersed in stock dispersion of nanopure water with 2% serum, but agglomerated and sedimented during exposure. FE1-Muta(TM) Mouse lung epithelial cells were exposed for 24 hr. The levels of DNA strand breaks (SB) were evaluated using the comet assay, a screening assay suitable for genotoxicity testing of nanomaterials. Exposure to MWCNT (12.5-200 µg/ml) did not induce significant cytotoxicity (viability above 92%). Cell proliferation was reduced in highest doses of some MWCNT after 24 hr, and was associated with generation of reactive oxygen species and high surface area. Increased levels of DNA SB were only observed for Group II consisting of MWCNT with large diameters and high Fe2 O3 and Ni content. Significantly, increased levels of SB were only observed at 200 µg/ml of MWCNT-042. Overall, the MWCNT were not cytotoxic and weakly genotoxic after 24 hr exposure to doses up to 200 µg/ml. © 2014 Wiley Periodicals, Inc.

  9. HTGR Fuel Recycle Development Program (189a OHO45). Fuel refabrication, Task 500. Rate-controlling factors in the carbothermic preparation of UO2--UC2--C microspheres

    International Nuclear Information System (INIS)

    Stinton, D.P.; Tiegs, S.M.; Lackey, W.J.; Lindemer, T.B.

    1979-01-01

    Rate controlling factors in the conversion of UO 2 + C microspheres to UC 2 + C were investigated using a 13-cm-dia fluidized bed furnace. X-ray diffraction, ion microprobe, and microstructural examination revealed that the conversion of UO 2 to UC 2 began at the surface of the microsphere and progressed toward the central unreacted core. Kinetic models for solid state reactions in spheres were evaluated by using quantitative mass spectrometric data on the rae of evolution of carbon monoxide during conversion. This analysis revealed that the rate of conversion was controlled by reaction at the outer surface of the microsphere. Also, decreased partial pressures of carbon monoxide were found to accelerate the rate of reaction

  10. Optically Levitated Microspheres as a Probe for New Interactions

    Science.gov (United States)

    Rider, Alexander; Moore, David; Blakemore, Charles; Lu, Marie; Gratta, Giorgio

    2016-03-01

    We are developing novel techniques to probe new interactions at micron distances using optically levitated dielectric microspheres. Levitated microspheres are an ideal probe for short-range interactions because they are suspended using the radiation pressure at the focus of a laser beam, which means that the microspheres can be precisely manipulated and isolated from the surrounding environment at high vacuum. We have performed a search for unknown charged particles bound within the bulk of the microspheres. Currently, we are searching for the presence of a Chameleon field postulated to explain the presence of dark energy in the universe. In the future we plan to use optically levitated microspheres to search for micron length-scale gravity like interactions that could couple between a microsphere and another mass. We will present resent results from these experiments and plans for future searches for new interactions.

  11. Synthesis of plastic scintillation microspheres: Alpha/beta discrimination

    International Nuclear Information System (INIS)

    Santiago, L.M.; Bagán, H.; Tarancón, A.; Garcia, J.F.

    2014-01-01

    Plastic scintillation microspheres (PSm) have been developed as an alternative for liquid scintillation cocktails due to their ability to avoid the mixed waste, besides other strengths in which the possibility for alpha/beta discrimination is included. The aim of this work was to evaluate the capability of PSm containing two combinations of fluorescence solutes (PPO/POPOP and pT/Bis-MSB) and variable amounts of a second organic solvent (naphthalene) to enhance the alpha/beta discrimination. Two commercial detectors with different Pulse Shape Discrimination performances (Quantulus and Triathler) were used to evaluate the alpha/beta discrimination. An optimal discrimination of alpha/beta particles was reached, with very low misclassification values (2% for beta particles and 0.5% for alpha particles), when PSm containing PPO/POPOP and between 0.6 and 2.0 g of naphthalene were evaluated using Triathler and the appropriate programme for data processing. - Highlights: • Plastic scintillation microspheres for α/β discrimination have been synthesised. • The energy transfer process in PSm with different compositions has been investigated. • The α/β discrimination capabilities of two commercial detectors have been evaluated. • 2% and 0.5% of misclassifications for β and α radionuclides have been achieved respectively

  12. Fragrance release profile from sonochemically prepared protein microsphere containers.

    Science.gov (United States)

    Tzhayik, Oshrat; Cavaco-Paulo, Artur; Gedanken, Aharon

    2012-07-01

    Protein microspheres have been prepared by sonicating a mixture of pure fragrant oil (amyl acetate (AA)) with an aqueous protein (bovine serum albumin) solution. The prepared protein spheres are nano- to micrometer sized with an encapsulation efficiency of approx. 97% for the AA present on the surface and inside the BSA capsule. Containers were found stable for more than 6 months when stored sealed at 4°C and 20°C. For the release profile measurements, we used a simple, automated and direct method. We continuously weighed the encapsulated microspheres and measured the evaporation rates. The release profiles at 15°C and 25°C display two different evaporation rates. The higher rate is the sum of a few evaporation rates, including water molecules, while the slower rate is due to the evaporation of pure AA. The changes in the evaporation rates occur upon the collapse of the container. This event coincides with the full evaporation of water. For morphological characterization we dyed the AA with Nile red, and used SEM, ESEM, Cryo-SEM, light microscopy, and confocal laser scanning microscopy measurements. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. Yttrium 90 microspheres for the treatment of hepatocellular carcinoma.

    Science.gov (United States)

    Memon, Khairuddin; Lewandowski, Robert J; Riaz, Ahsun; Salem, Riad

    2013-01-01

    Yttrium-90 microspheres are radioactive particles which are increasingly being employed for treating patients with unresectable hepatocellular carcinoma (HCC). The procedure is called radioembolization. It involves the injection of micron-sized embolic particles loaded with a radioisotope by use of transarterial techniques. Because of the sensitivity of liver parenchyma and relative insensitivity of tumor, external radiation has played a limited role in treating HCC. (90)Y administered via arterial route directs the highly concentrated radiation to the tumor while healthy liver parenchyma is relatively spared due to its preferential blood supply from portal venous blood. This technique has proven useful for the majority of patients with HCC as most of them present in advanced stage, beyond potentially curative options (resection/liver transplantation). (90)Y microspheres can be used in downstaging large tumors to bring within transplantable criteria, in patients with portal venous thrombosis due to tumor invasion and as palliative therapy. There are two available devices for (90)Y administration; TheraSphere® (glass based) and SIR-Spheres® (resin based). The procedure is performed on an outpatient basis. The incidence of complications is comparatively less and may include nausea, fatigue, abdominal pain, hepatic dysfunction, biliary injury, fibrosis, radiation pneumonitis, GI ulcers, and vascular injury; however, these can be avoided by meticulous pretreatment assessment, careful patient selection, and adequate dosimetry. This article explores the technical and clinical aspects of (90)Y radioembolization with keeping emphasis on patient selection, uses, and complications.

  14. Investigation of the parameters affecting the release of flurbiprofen from chitosan microspheres

    Directory of Open Access Journals (Sweden)

    Müşerref Günseli Yüksel Tilkan

    2018-04-01

    Full Text Available ABSTRACT Flurbiprofen (FLB, a NSAID, widely used for preventing pain generally for arthritis or dental problems. In this study, FLB loaded chitosan microspheres were prepared by ionotropic gelation method. In this method, microspheres were formed by dropping chitosan solutions containing FLB into sodium alginate solutions including sodium tripolyphosphate (TPP. A variety of formulation parameters like drug:polymer ratio, drug concentration, polymer’s molecular weight, polymer concentration, pH and the concentration of TPP solutions, drying method and stirring time were analyzed. The dissolution studies were performed in a shaking water bath in pH 7.4 phosphate buffer saline (PBS at 37 °C. Laser diffractometer was used for particle size analysis, and scanning electron microscope (SEM was used for morphological properties. Drug loading and loading efficiency were calculated by using UV spectrophotometer. The particles obtained were spherical with 0.7-1.3 mm size range, and the loading efficiency was approximately 21-79%. The dissolution studies conducted revealed that drug:polimer ratio and the polymer type and concentration affected the drug release from microspheres. It was observed that increasing the polymer concentration, polymer’s molecular weight and TPP concentration decreased the FLB release from microspheres, which was according to Higuchi kinetics.

  15. K88 Fimbrial Adhesin Targeting of Microspheres Containing Gentamicin Made with Albumin Glycated with Lactose

    Science.gov (United States)

    Sarabia-Sainz, Andre-i; Sarabia-Sainz, Hector Manuel; Ramos-Clamont Montfort, Gabriela; Mata-Haro, Veronica; Guzman-Partida, Ana María; Guzman, Roberto; Garcia-Soto, Mariano; Vazquez-Moreno, Luz

    2015-01-01

    The formulation and characterization of gentamicin-loaded microspheres as a delivery system targeting enterotoxigenic Escherichia coli K88 (E. coli K88) was investigated. Glycated albumin with lactose (BSA-glucose-β (4-1) galactose) was used as the microsphere matrix (MS-Lac) and gentamicin included as the transported antibiotic. The proposed target strategy was that exposed galactoses of MS-Lac could be specifically recognized by E. coli K88 adhesins, and the delivery of gentamicin would inhibit bacterial growth. Lactosylated microspheres (MS-Lac1, MS-Lac2 and MS-Lac3) were obtained using a water-in-oil emulsion, containing gentamicin, followed by crosslinking with different concentrations of glutaraldehyde. Electron microscopy displayed spherical particles with a mean size of 10–17 µm. In vitro release of gentamicin from MS-Lac was best fitted to a first order model, and the antibacterial activity of encapsulated and free gentamicin was comparable. MS-Lac treatments were recognized by plant galactose-specific lectins from Ricinus communis and Sophora japonica and by E. coli K88 adhesins. Results indicate MS-Lac1, produced with 4.2 mg/mL of crosslinker, as the best treatment and that lactosylated microsphere are promising platforms to obtain an active, targeted system against E. coli K88 infections. PMID:26389896

  16. K88 Fimbrial Adhesin Targeting of Microspheres Containing Gentamicin Made with Albumin Glycated with Lactose

    Directory of Open Access Journals (Sweden)

    Andre-i Sarabia-Sainz

    2015-09-01

    Full Text Available The formulation and characterization of gentamicin-loaded microspheres as a delivery system targeting enterotoxigenic Escherichia coli K88 (E. coli K88 was investigated. Glycated albumin with lactose (BSA-glucose-β (4-1 galactose was used as the microsphere matrix (MS-Lac and gentamicin included as the transported antibiotic. The proposed target strategy was that exposed galactoses of MS-Lac could be specifically recognized by E. coli K88 adhesins, and the delivery of gentamicin would inhibit bacterial growth. Lactosylated microspheres (MS-Lac1, MS-Lac2 and MS-Lac3 were obtained using a water-in-oil emulsion, containing gentamicin, followed by crosslinking with different concentrations of glutaraldehyde. Electron microscopy displayed spherical particles with a mean size of 10–17 µm. In vitro release of gentamicin from MS-Lac was best fitted to a first order model, and the antibacterial activity of encapsulated and free gentamicin was comparable. MS-Lac treatments were recognized by plant galactose-specific lectins from Ricinus communis and Sophora japonica and by E. coli K88 adhesins. Results indicate MS-Lac1, produced with 4.2 mg/mL of crosslinker, as the best treatment and that lactosylated microsphere are promising platforms to obtain an active, targeted system against E. coli K88 infections.

  17. Selective adsorption and separation of organic dyes from aqueous solution on polydopamine microspheres.

    Science.gov (United States)

    Fu, Jianwei; Xin, Qianqian; Wu, Xuechen; Chen, Zhonghui; Yan, Ya; Liu, Shujun; Wang, Minghuan; Xu, Qun

    2016-01-01

    Polydopamine (PDA) microspheres, synthesized by a facile oxidation polymerization route, were evaluated as a potential adsorbent for selective adsorption and separation of organic dyes. The adsorption processes towards nine water-soluble dyes (anionic dyes: methyl orange (MO), eosin-Y (EY), eosin-B (EB), acid chrome blue K (ACBK), neutral dye: neutral red (NR), and cationic dyes: rhodamine B (RhB), malachite green (MG), methylene blue (MB), safranine T (ST)) were thoroughly investigated. The adsorption selectivity of organic dyes onto PDA microspheres was successfully applied for the separation of dyes mixtures. Various influential factors such as solution pH, temperature, and contact time were employed to ascertain the optimal condition for adsorption of representative organic dyes including MB, MG and NR. The pseudo-first-order and pseudo-second-order kinetics models were used to fit the adsorption kinetics process. Five isothermal adsorption models (Langmuir, Dubnin-Radushkevich, Temkin, Freundlich and Harkins-Jura) were used to investigate the adsorption thermodynamics properties. The results showed that the PDA microspheres owned good selective adsorption ability towards cationic dyes. The adsorption kinetics process conformed to the pseudo-second-order kinetics model and the Langmuir isotherm model was more appropriate for tracing the adsorption behavior than other isotherm models. Thus, we can conclude PDA microspheres may be a high-efficiency selective adsorbent towards some cationic dyes. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Templated preparation of porous magnetic microspheres and their application in removal of cationic dyes from wastewater.

    Science.gov (United States)

    Liu, Qingquan; Wang, Li; Xiao, Anguo; Gao, Jingming; Ding, Wenbing; Yu, Haojie; Huo, Jia; Ericson, Mårten

    2010-09-15

    Porous magnetic microspheres with large particle size (350-450 microm) were prepared with sulfonated macroporous polydivinylbenzene as a template. The preparation process included ferrous ion exchange and following oxidation by hydrogen peroxide. The results showed that the weight fraction of magnetic nanoparticles exceeded 20 wt% in microspheres after the preparation process was repeated three times. X-ray diffraction profiles indicated that the crystalline phase of as-formed magnetic nanoparticles was magnetite (Fe(3)O(4)). TEM images revealed rod-like magnetite crystal after the first oxidation cycle, however, the crystal morphologies were transferred into random shape after more oxidation cycles. The applicability of porous magnetic microspheres for removal of cationic dyes from water was also explored. The results exhibited that basic fuchsin and methyl violet could be quickly removed from water with high efficiency. More importantly, the magnetic microspheres could be easily regenerated and repeatedly employed for wastewater treatment. Therefore, a novel methodology was provided for fast removal cationic dyes from wastewater. Copyright 2010 Elsevier B.V. All rights reserved.

  19. Novel syntactic foams made of ceramic hollow micro-spheres and starch: theory, structure and properties

    Energy Technology Data Exchange (ETDEWEB)

    Islam, M.M.; Kim, H.S. [University of Newcastle, Callaghan, NSW (Australia). Faculty of Engineering & Built Environments

    2007-08-15

    Novel syntactic foams for potential building material applications were developed using starch as binder and ceramic hollow micro-spheres available as waste from coal-fired power stations. Foams of four different micro-sphere size groups were manufactured with either pre- or post-mould gelatinization process. They were of ternary system including voids with a foam density range of approximately 0.33-0.44 g/cc. Compressive failure behaviour and mechanical properties of the manufactured foams were evaluated. Not much difference in failure behaviour or in mechanical properties between the two different processes (pre- and post-mould gels) was found for a given binder content. Compressive failure of all syntactic foams was of shear on plane inclined 45 degrees to compressive loading direction. Failure surfaces of most syntactic foams were characterized by debonded micro-spheres. Compressive strength and modulus of syntactic foams were found to be dependant mainly on binder content but mostly independent of micro-sphere size. Some conditions of relativity arising from properties of constituents leading to the rule of mixtures relationships for compressive strength and to understanding of compressive/transitional failure behaviour were developed. The developed relationships based on the rule of mixtures were partially verified. Some formation of starch webs on failure surfaces was discussed.

  20. [Studies on preparation technology of microspheres of contraceptives].

    Science.gov (United States)

    Lei, Y; Lu, B

    1993-01-01

    Contraceptive poly ethylglycol-lactide (PEGL), an artificial biodegradable polymer microsphere was prepared by a solvent evaporation process using levonorgestrel (LNG) and estradiol (E2) as model drugs and PEGL as the core material. The experimental conditions were optimized, the mean volume diameter obtained being 30 microns and rate of encapsulation 75-82%. In vitro, it was found that the drug release rate decreased with decreasing drug content in the microspheres. The microspheres of the contraceptive maintained anticonception duration in mice for over 6 months, indicating that the microspheres have remarkably long acting sustained release action.

  1. Preparation and characterization of immobilized lipase on magnetic hydrophobic microspheres

    DEFF Research Database (Denmark)

    Guo, Zheng; Bai, Shu; Sun, Yan

    2003-01-01

    A novel magnetic poly(vinyl acetate (VAc)–divinyl benzene (DVB)) material (8–34 μm) was synthesized by copolymerization of vinyl acetate and divinyl benzene using oleic acid-stabilized magnetic colloids as magnetic cores. The magnetic colloids and the copolymer microspheres were characterized...... with transmission and scanning electron microscopes, respectively. Magnetization of the microspheres could be described by the Langevin function. All the observations indicated that the microspheres were superparamagnetic. Magnetic sedimentation of the microspheres was achieved within 3 min, over 300 times faster...... recovered by magnetic separations....

  2. PLGA and PHBV Microsphere Formulations and Solid-State Characterization

    DEFF Research Database (Denmark)

    Yang, Chiming; Plackett, David; Needham, David

    2009-01-01

    To develop and characterize the solid-state properties of poly(DL-lactic-co-glycolic acid) (PLGA) and poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) (PHBV) microspheres for the localized and controlled release of fusidic acid (FA). The effects of FA loading and polymer composition on the mean...... diameter, encapsulation efficiency and FA released from the microspheres were determined. The solid-state and phase separation properties of the microspheres were characterized using DSC, XRPD, Raman spectroscopy, SEM, laser confocal and real time recording of single microspheres formation. Above a loading...

  3. Synthesis of raspberry-like magnetic polystyrene microspheres

    International Nuclear Information System (INIS)

    Xu Zhizhong; Xia Ao; Wang Changchun; Yang Wuli; Fu Shoukuang

    2007-01-01

    Raspberry-like magnetic polystyrene microspheres were prepared via soap-free emulsion polymerization using 2,2'-azobis(2-methylpropionamidine) dihydrochloride (V50) as initiator. The effect of polymerization parameters, such as initiator type, initiator content and the feeding sequence on the particle size and morphology of magnetic polystyrene microspheres, were examined. The final magnetic polystyrene microspheres were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM) and thermogravimetric analysis (TGA). The experimental results showed that V50 was a suitable initiator for preparation of raspberry-like magnetic polystyrene microspheres

  4. Histological Comparison of Kidney Tissue Following Radioembolization with Yttrium-90 Resin Microspheres and Embolization with Bland Microspheres.

    Science.gov (United States)

    de Silva, Suresh; Mackie, Simon; Aslan, Peter; Cade, David; Delprado, Warick

    2016-12-01

    Intra-arterial brachytherapy with yttrium-90 ( 90 Y) resin microspheres (radioembolization) is a procedure to selectively deliver high-dose radiation to tumors. The purpose of this research was to compare the radioembolic effect of 90 Y-radioembolization versus the embolic effect of bland microspheres in the porcine kidney model. In each of six pigs, ~25-33 % of the kidney volume was embolized with 90 Y resin microspheres and an equivalent number of bland microspheres in the contralateral kidney. Kidney volume was estimated visually from contrast-enhanced fluoroscopy imaging. Morphologic and histologic analysis was performed 8-9 weeks after the procedure to assess the locations of the microspheres and extent of tissue necrosis from 90 Y-radioembolization and bland embolization. A semi-quantified evaluation of the non-acute peri-particle and perivascular tissue reaction was conducted. All guidelines for the care and use of animals were followed. Kidneys embolized with 90 Y-radioembolization decreased in mass by 30-70 % versus the contralateral kidney embolized with bland microspheres. These kidneys showed significant necrosis/fibrosis, avascularization, and glomerular atrophy in the immediate vicinity of the 90 Y resin microspheres. By contrast, glomerular changes were not observed, even with clusters of bland microspheres in afferent arterioles. Evidence of a foreign body reaction was recorded in some kidneys with bland microspheres, and subcapsular scarring/infarction only with the highest load (4.96 × 10 6 ) of bland microspheres. This study showed that radioembolization with 90 Y resin microspheres produces localized necrosis/fibrosis and loss of kidney mass in a porcine kidney model. This result supports the study of 90 Y resin microspheres for the localized treatment of kidney tumors.

  5. Histological Comparison of Kidney Tissue Following Radioembolization with Yttrium-90 Resin Microspheres and Embolization with Bland Microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Suresh de, E-mail: suresh.desilva@unsw.edu.au [Southern Radiology Group, Radiology Department Sutherland Hospital (Australia); Mackie, Simon [Western General Hospital, Department of Urology (United Kingdom); Aslan, Peter [St George Hospital, Department of Urology (Australia); Cade, David [Sirtex Technology Pty Ltd (Australia); Delprado, Warick [Douglass Hanly Moir Pathology (Australia)

    2016-12-15

    BackgroundIntra-arterial brachytherapy with yttrium-90 ({sup 90}Y) resin microspheres (radioembolization) is a procedure to selectively deliver high-dose radiation to tumors. The purpose of this research was to compare the radioembolic effect of {sup 90}Y-radioembolization versus the embolic effect of bland microspheres in the porcine kidney model.MethodsIn each of six pigs, ~25–33 % of the kidney volume was embolized with {sup 90}Y resin microspheres and an equivalent number of bland microspheres in the contralateral kidney. Kidney volume was estimated visually from contrast-enhanced fluoroscopy imaging. Morphologic and histologic analysis was performed 8–9 weeks after the procedure to assess the locations of the microspheres and extent of tissue necrosis from {sup 90}Y-radioembolization and bland embolization. A semi-quantified evaluation of the non-acute peri-particle and perivascular tissue reaction was conducted. All guidelines for the care and use of animals were followed.ResultsKidneys embolized with {sup 90}Y-radioembolization decreased in mass by 30–70 % versus the contralateral kidney embolized with bland microspheres. These kidneys showed significant necrosis/fibrosis, avascularization, and glomerular atrophy in the immediate vicinity of the {sup 90}Y resin microspheres. By contrast, glomerular changes were not observed, even with clusters of bland microspheres in afferent arterioles. Evidence of a foreign body reaction was recorded in some kidneys with bland microspheres, and subcapsular scarring/infarction only with the highest load (4.96 × 10{sup 6}) of bland microspheres.ConclusionThis study showed that radioembolization with {sup 90}Y resin microspheres produces localized necrosis/fibrosis and loss of kidney mass in a porcine kidney model. This result supports the study of {sup 90}Y resin microspheres for the localized treatment of kidney tumors.

  6. Histological Comparison of Kidney Tissue Following Radioembolization with Yttrium-90 Resin Microspheres and Embolization with Bland Microspheres

    International Nuclear Information System (INIS)

    Silva, Suresh de; Mackie, Simon; Aslan, Peter; Cade, David; Delprado, Warick

    2016-01-01

    BackgroundIntra-arterial brachytherapy with yttrium-90 ( 90 Y) resin microspheres (radioembolization) is a procedure to selectively deliver high-dose radiation to tumors. The purpose of this research was to compare the radioembolic effect of 90 Y-radioembolization versus the embolic effect of bland microspheres in the porcine kidney model.MethodsIn each of six pigs, ~25–33 % of the kidney volume was embolized with 90 Y resin microspheres and an equivalent number of bland microspheres in the contralateral kidney. Kidney volume was estimated visually from contrast-enhanced fluoroscopy imaging. Morphologic and histologic analysis was performed 8–9 weeks after the procedure to assess the locations of the microspheres and extent of tissue necrosis from 90 Y-radioembolization and bland embolization. A semi-quantified evaluation of the non-acute peri-particle and perivascular tissue reaction was conducted. All guidelines for the care and use of animals were followed.ResultsKidneys embolized with 90 Y-radioembolization decreased in mass by 30–70 % versus the contralateral kidney embolized with bland microspheres. These kidneys showed significant necrosis/fibrosis, avascularization, and glomerular atrophy in the immediate vicinity of the 90 Y resin microspheres. By contrast, glomerular changes were not observed, even with clusters of bland microspheres in afferent arterioles. Evidence of a foreign body reaction was recorded in some kidneys with bland microspheres, and subcapsular scarring/infarction only with the highest load (4.96 × 10 6 ) of bland microspheres.ConclusionThis study showed that radioembolization with 90 Y resin microspheres produces localized necrosis/fibrosis and loss of kidney mass in a porcine kidney model. This result supports the study of 90 Y resin microspheres for the localized treatment of kidney tumors.

  7. Micro-radiography for the characterization of coated fuel microspheres for CHTR

    International Nuclear Information System (INIS)

    Chandrasekharan, K.N.; Kumar, Arun; Kamath, H.S.

    2011-01-01

    India is pursuing the design of a Compact High Temperature Reactor (CHTR), which is basically a technology demonstrator for high temperature process heat applications such as Hydrogen production or secondary hydrocarbons as a substitute for primary fossil fuel. The probable option of the fuel for CHTR being 233 UO 2 and ThO 2 based TRISO coated microspheres in the form of fuel compacts, fabrication of coated fuel and its characterization and Quality Control (QC) is one of the key areas where research and development work is being carried out. As part of the development of QC techniques, an attempt has been made in the Bhabha Atomic Research Centre to develop X-ray micro-radiography for the evaluation of coated fuel microspheres. One of the important characteristic to be measured during the quality control of the TRISO coated fuel particles for CHTR is the thickness measurement of the various coating layers. The nondestructive testing method employed for this purpose shall distinguish the layers clearly and shall be amenable for automation as the sample size involved is large. Use of X-rays as a probing tool was explored for the characterization of the fuel microspheres and the thickness measurement of Silicon Carbide (SiC) coating. The difference in the low energy X-ray transmission through carbon coating and through SiC coating has been utilized to get a good image contrast in the radiograph. It was possible to measure the SiC coating thickness employing digital image analysis of the micro-radiographs. This technique detects the size, shape and integrity of the microspheres in addition to the measurement of coating thickness. The technique involves taking contact X-ray radiograph of the microspheres on high resolution X-ray films using a fine focus X-ray source. The processed X-ray film is then magnified using a profile projector and the digitized image is used for quantitative measurement of the fuel kernel and the coating thickness. The development of micro

  8. Silicon Composite Anode Materials for Lithium Ion Batteries Based on Carbon Cryogels and Carbon Paper

    Science.gov (United States)

    Woodworth, James; Baldwin, Richard; Bennett, William

    2010-01-01

    A variety of materials are under investigation for use as anode materials in lithium-ion batteries, of which, the most promising are those containing silicon. One such material is a composite formed via the dispersion of silicon in a resorcinol-formaldehyde (RF) gel followed by pyrolysis. Two silicon-carbon composite materials, carbon microspheres and nanofoams produced from nano-phase silicon impregnated RF gel precursors have been synthesized and investigated. Carbon microspheres are produced by forming the silicon-containing RF gel into microspheres whereas carbon nanofoams are produced by impregnating carbon fiber paper with the silicon containing RF gel to create a free standing electrode. Both materials have demonstrated their ability to function as anodes and utilize the silicon present in the material. Stable reversible capacities above 400 mAh/g for the bulk material and above 1000 mAh/g of Si have been observed.

  9. Carbon Cryogel and Carbon Paper-Based Silicon Composite Anode Materials for Lithium-Ion Batteries

    Science.gov (United States)

    Woodworth, James; Baldwin, Richard; Bennett, William

    2010-01-01

    A variety of materials are under investigation for use as anode materials in lithium-ion batteries, of which, the most promising are those containing silicon. 6 One such material is a composite formed via the dispersion of silicon in a resorcinol-formaldehyde (RF) gel followed by pyrolysis. Two silicon-carbon composite materials, carbon microspheres and nanofoams produced from nano-phase silicon impregnated RF gel precursors have been synthesized and investigated. Carbon microspheres are produced by forming the silicon-containing RF gel into microspheres whereas carbon nano-foams are produced by impregnating carbon fiber paper with the silicon containing RF gel to create a free standing electrode. 1-5 Both materials have demonstrated their ability to function as anodes and utilize the silicon present in the material. Stable reversible capacities above 400 mAh/g for the bulk material and above 1000 mAh/g of Si have been observed.

  10. Optical Microspherical Resonators for Biomedical Sensing

    Directory of Open Access Journals (Sweden)

    Giancarlo C. Righini

    2011-01-01

    Full Text Available Optical resonators play an ubiquitous role in modern optics. A particular class of optical resonators is constituted by spherical dielectric structures, where optical rays are total internal reflected. Due to minimal reflection losses and to potentially very low material absorption, these guided modes, known as whispering gallery modes, can confer the resonator an exceptionally high quality factor Q, leading to high energy density, narrow resonant-wavelength lines and a lengthy cavity ringdown. These attractive characteristics make these miniaturized optical resonators especially suited as laser cavities and resonant filters, but also as very sensitive sensors. First, a brief analysis is presented of the characteristics of microspherical resonators, of their fabrication methods, and of the light coupling techniques. Then, we attempt to overview some of the recent advances in the development of microspherical biosensors, underlining a number of important applications in the biomedical field.

  11. Microsphere Assemblies via Phosphonate Monoester Coordination Chemistry.

    Science.gov (United States)

    Bladek, Kamila J; Reid, Margaret E; Nishihara, Hirotomo; Akhtar, Farid; Gelfand, Benjamin S; Shimizu, George K H

    2018-02-01

    By complexing a bent phosphonate monoester ligand with cobalt(II), coupled with in situ ester hydrolysis, coordination microspheres (CALS=CALgary Sphere) are formed whereas the use of the phosphonic acid directly resulted in a sheet-like structure. Manipulation of the synthetic conditions gave spheres with different sizes, mechanical stabilities, and porosities. Time-dependent studies determined that the sphere formation likely occurred through the formation of a Co 2+ and ligand chain that propagates in three dimensions through different sets of interactions. The relative rates of these assembly processes versus annealing by ester hydrolysis and metal dehydration determine the growth of the microspheres. Hardness testing by nanoindentation is carried out on the spheres and sheets. Notably, no templates or capping agents are employed, the growth of the spheres is intrinsic to the ligand geometry and the coordination chemistry of cobalt(II) and the phosphonate monoester. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Scaffolds for bone regeneration made of hydroxyapatite microspheres in a collagen matrix

    Energy Technology Data Exchange (ETDEWEB)

    Cholas, Rahmatullah, E-mail: rahmat.cholas@gmail.com; Kunjalukkal Padmanabhan, Sanosh, E-mail: sanosh2001@gmail.com; Gervaso, Francesca; Udayan, Gayatri; Monaco, Graziana; Sannino, Alessandro; Licciulli, Antonio

    2016-06-01

    Biomimetic scaffolds with a structural and chemical composition similar to native bone tissue may be promising for bone tissue regeneration. In the present work hydroxyapatite mesoporous microspheres (mHA) were incorporated into collagen scaffolds containing an ordered interconnected macroporosity. The mHA were obtained by spray drying of a nano hydroxyapatite slurry prepared by the precipitation technique. X-ray diffraction (XRD) analysis revealed that the microspheres were composed only of hydroxyapatite (HA) phase, and energy-dispersive x-ray spectroscopy (EDS) analysis revealed the Ca/P ratio to be 1.69 which is near the value for pure HA. The obtained microspheres had an average diameter of 6 μm, a specific surface area of 40 m{sup 2}/g as measured by Brunauer-Emmett-Teller (BET) analysis, and Barrett-Joyner-Halenda (BJH) analysis showed a mesoporous structure with an average pore diameter of 16 nm. Collagen/HA-microsphere (Col/mHA) composite scaffolds were prepared by freeze-drying followed by dehydrothermal crosslinking. SEM observations of Col/mHA scaffolds revealed HA microspheres embedded within a porous collagen matrix with a pore size ranging from a few microns up to 200 μm, which was also confirmed by histological staining of sections of paraffin embedded scaffolds. The compressive modulus of the composite scaffold at low and high strain values was 1.7 and 2.8 times, respectively, that of pure collagen scaffolds. Cell proliferation measured by the MTT assay showed more than a 3-fold increase in cell number within the scaffolds after 15 days of culture for both pure collagen scaffolds and Col/mHA composite scaffolds. Attractive properties of this composite scaffold include the potential to load the microspheres for drug delivery and the controllability of the pore structure at various length scales. - Highlights: • Mesoporous hydroxyapatite microsphere(mHA) synthesized by spray drying method • Porous collagen/mHA composite scaffold made by freeze

  13. Sputter coating of microspherical substrates by levitation

    Science.gov (United States)

    Lowe, A.T.; Hosford, C.D.

    Microspheres are substantially uniformly coated with metals or nonmetals by simltaneously levitating them and sputter coating them at total chamber pressures less than 1 torr. A collimated hole structure comprising a parallel array of upwardly projecting individual gas outlets is machined out to form a dimple. Glass microballoons,, which are particularly useful in laser fusion applications, can be substantially uniformly coated using the coating method and apparatus.

  14. Intracardiac Echocardiography Guided Transeptal Catheter Injection of Microspheres for Assessment of Cerebral Microcirculation in Experimental Models

    Directory of Open Access Journals (Sweden)

    Judith Bellapart

    2013-01-01

    Full Text Available The use of microspheres for the determination of regional microvascular blood flow (RMBF has previously used different approaches. This study presents for the first time the intracardiac injection of microspheres using transeptal puncture under intracardiac echocardiography guidance. Five Merino sheep were instrumented and cardiovascularly supported according to local guidelines. Two catheter sheaths into the internal jugular vein facilitated the introduction of an intracardiac probe and transeptal catheter, respectively. Five million colour coded microspheres were injected into the left atrium via this catheter. After euthanasia the brain was used as proof of principle and the endpoint for determination of microcirculation at different time points. Homogeneous allocation of microspheres to different regions of the brain was found over time. Alternate slices from both hemispheres showed the following flow ranges: for slice 02; 0.57–1.02 mL/min/g, slice 04; 0.45–1.42 mL/min/g, slice 06; 0.35–1.87 mL/min/g, slice 08; 0.46–1.77 mL/min/g, slice 10; 0.34–1.28 mL/min/g. A mixed effect regression model demonstrated that the confidence interval did include zero suggesting that the apparent variability intra- and intersubject was not statistically significant, supporting the stability and reproducibility of the injection technique. This study demonstrates the feasibility of the transeptal injection of microspheres, showing a homogeneous distribution of blood flow through the brain unchanged over time and has established a new interventional model for the measurement of RMBF in ovine models.

  15. Vacuum injection system for hydrogen micro-spheres in the CELSIUS storage ring

    International Nuclear Information System (INIS)

    Tinoco, Hernan.

    1990-01-01

    The use of hydrogen micro-spheres as internal targets in the CELSIUS storage ring has been proposed for light meson rare decay measurements. The target generation apparatus design is based on that developed for refueling of fusion tokamak reactors. The micro-spheres are produced by acoustic excitation of a liquid hydrogen jet, and are injected into vacuum for the experiments by means of a hydrogen gas flow through an injection nozzle. The work reported here is an analysis of the gas flow in the injection nozzle, of the entrained motion of the micro-spheres considered as spherical particles, and of the heat transfer between them and the gas. The computation of the heat transfer allows the determination of the conditions under which the evaporation of the micro-spheres is negligible. It is shown that the gas must be cooled to temperatures near that of the micro-spheres for these to survive. Together with the computation of the gas flow and particle motion, the analysis includes the design of the injection nozzle. The requirements of well defined mass flow rate and low perturbation level suggest a nozzle consisting of a contraction region and a straight region with constant cross-sectional area. This nozzle is to be operated with stagnation conditions near the triple point conditions and choked flow at the exit. The condition of a limiting mass flow rate of the order of 10 -6 kg/s together with the operating conditions bound the exit diameter to values of 200-250 μm. Other geometrical parameters have only a subordinate importance on the injection nozzle design

  16. STRUCTURING OF DIAMOND FILMS USING MICROSPHERE LITHOGRAPHY

    Directory of Open Access Journals (Sweden)

    Mária Domonkos

    2014-10-01

    Full Text Available In this study, the structuring of micro- and nanocrystalline diamond thin films is demonstrated. The structuring of the diamond films is performed using the technique of microsphere lithography followed by reactive ion etching. Specifically, this paper presents a four-step fabrication process: diamond deposition (microwave plasma assisted chemical vapor deposition, mask preparation (by the standard Langmuir-Blodgett method, mask modification and diamond etching. A self-assembled monolayer of monodisperse polystyrene (PS microspheres with close-packed ordering is used as the primary template. Then the PS microspheres and the diamond films are processed in capacitively coupled radiofrequency plasma  using different plasma chemistries. This fabrication method illustrates the preparation of large arrays of periodic and homogeneous hillock-like structures. The surface morphology of processed diamond films is characterized by scanning electron microscopy and atomic force microscope. The potential applications of such diamond structures in various fields of nanotechnology are also briefly discussed.

  17. Adsorption behavior of protein onto siloxane microspheres

    International Nuclear Information System (INIS)

    Liu Bailing; Cao Shunsheng; Deng Xiaobo; Li Songjun; Luo Rong

    2006-01-01

    The siloxane microspheres with core-shell structure (PMMA/PMPS) (MMA, methyl methacrylate; MPS, 3-methacryloxypropyl-trimethoxysilane) have been prepared by dispersion polymerization as described in our previous work. In this paper, the developed poly(MMA-MPS) microspheres, as a carrier, are used to investigate the adsorption behavior of bovine serum albumin (BSA) on them. The Langmuir and Freundlich models have been applied to describe the adsorption behavior. The experimental results indicated that the presence of PMPS evidently increases the adsorption rate and the amount of protein, and it also influences the interaction of BSA molecules. The adsorption of BSA on the poly(MMA-MPS) microspheres seems to be sensitive to pH and ionic strength. The fittings curves from Langmuir and Freundlich models showed that the adsorption was actually more complicated than ideal situation because one or more interactions were involved in the process. For understanding the electronic contribution, the Zeta potential was used to measure the reactive system before and after protein adsorption

  18. Glass microspheres covering film: first field evaluations

    International Nuclear Information System (INIS)

    Magnani, G.; Filippi, F.

    2006-01-01

    A trial was carried out to evaluate, in the North-Centre of Italy, the behaviour in field of a new plastic covering film, prepared with the inclusion of empty glass microspheres (Solex). The trial was conducted on tomato (Lycopersicon esculentum L.) and eggplant (Solanum melongena L.). The new film was compared to a covering film with the same optical (diffuse light) and constitutional (co-extruded three layers EVA-WPE) characteristics. Since the first results, the innovative film showed a better behaviour than the control one. It presented light and thermal conditions (lower temperature during the day and slightly higher temperature in the night, compared to the control film) that allowed a better growth and yield than the control film. The growth analysis of tomato showed that plants grown under glass microsphere film had an higher growth rate (dry weight/days) and thickness of leaves compared to the control one. The yield of tomato and eggplant presented an increase in plants cultivated under the innovative film, especially for number and weight of fruits. The commercial quality did not show any differences between the films, except for the flesh hardness of tomato: this could be explained with the fact that the glass microspheres film provides environmental conditions avoiding plant stress during some stages of its cycle [it

  19. Effective parameters in determining cross-linked dextran microsphere characteristics: screening by Plackett-Burman design-of-experiments.

    Science.gov (United States)

    Kenari, Hamed Salimi; Alinejad, Zeinab; Imani, Mohammad; Nodehi, Azizollah

    2013-01-01

    This study aims to screen the effective parameters in preparing cross-linked dextran microspheres (CDMs) to make them controllable for obtaining microspheres with tunable properties. Microspheres were prepared by chemical crosslinking of dextran dissolved in internal phase of an inverse emulsion system (W/O) using epichlorohydrin (ECH). A Plackett-Burman design-of-experiments was employed as the screening methodology to investigate the effects of the kinetics and process parameters, i.e. the mixing speed and emulsification time on the resulting microsphere characteristics. Crosslinking reaction temperature and concentrations of the emulsion constituents including dextran, ECH and sodium hydroxide were the studied kinetic parameters. Equilibrium swelling ratio, mean particle size and size distribution of the resulting CDMs were measured and statistically analysed. It was found that dextran concentration is the most influential parameter on the particle size and swelling ratio of the obtained CDMs. Increasing dextran concentration in the aqueous phase leads to a significant increase in the mean particle size and decrement in water uptake capacity of the resulting microspheres, respectively.

  20. An Amperometric Acetylcholinesterase Sensor Based on the Bio-templated Synthesis of Hierarchical Mesoporous Bioactive Glass Microspheres

    Science.gov (United States)

    Lv, Zhuo; Luo, Ruiping; Xi, Lijuan; Chen, Yang; Wang, Hongsu

    2017-11-01

    This work describes the synthesis of three-dimensional hollow hierarchical mesoporous bioactive glass (HMBG) microspheres based on Herba leonuri pollen grains via a hydrothermal method. The HMBG microspheres perfectly copied the hierarchical porous structure and inner hollow structure constituting the double-layer surface of the natural Herba leonuri pollen grains. This structural mimicry of the pollen grains resulted in a higher degree of adsorption of acetylcholinesterase (AChE) on HMBG microspheres in comparison with mesoporous bioactive glass. Subsequently, an amperometric biosensor for the detection of Malathion was fabricated by immobilizing AChE onto an HMBG microspheres-modified carbon paste electrode. The biosensor response exhibited two good linear ranges during an incubation time of 10 min in the malathion concentration ranges of 0.02-50 ppb and 50-600 ppb, with a detection limit of 0.0135 ppb ( S/ N = 3). Overall, the prepared enzymatic biosensor showed high sensitivity in the rapid detection of Malathion and could be applied to detect pesticide residues in vegetable matter.

  1. Yttrium-90 microsphere radioembolisation for unresectable hepatocellular carcinoma.

    Science.gov (United States)

    Abdel-Rahman, Omar M; Elsayed, Zeinab

    2016-02-16

    Hepatocellular carcinoma is the most common liver neoplasm and the fifth most common cancer worldwide. Moreover, its incidence has increased dramatically since the mid-2000s. While surgical resection and liver transplantation are the main curative treatments, only around 20% of people with early hepatocellular carcinoma may benefit from these therapies. Current treatment options for unresectable hepatocellular carcinoma include various ablative and trans-arterial therapies in addition to the drug sorafenib. To determine the benefits and harms of yttrium-90 microsphere trans-arterial radioembolisation either as a monotherapy or in combination with other systemic or locoregional therapies versus placebo, no treatment, or other similar systemic or locoregional therapies for people with unresectable hepatocellular carcinoma. We reviewed data from the Cochrane Hepato-Biliary Controlled Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and Science Citation Index Expanded. We also checked reference lists of primary original studies and review articles manually for further related articles (cross-references) up to December 2015. Eligible studies included all randomised clinical trials comparing yttrium-90-90 microsphere radioembolisation either as a monotherapy or in combination with other systemic or locoregional therapies versus placebo, no treatment, or other systemic or locoregional therapies for unresectable hepatocellular carcinoma. The two review authors independently extracted the relevant information on participant characteristics, interventions, study outcomes, and data on the outcomes for this review, as well as information on the design and methodology of the studies. The two review authors assessed risk of bias of the included trials using pre-defined risk of bias domains. We used Trial Sequential Analysis to control the risk of random errors. We assessed the methodological quality with GRADE. Two randomised clinical

  2. Basic fibroblast growth factor eluting microspheres enhance distraction enterogenesis.

    Science.gov (United States)

    Rouch, Joshua D; Scott, Andrew; Jabaji, Ziyad B; Chiang, Elvin; Wu, Benjamin M; Lee, Steven L; Shekherdimian, Shant; Dunn, James C Y

    2016-06-01

    The purpose of this study was to determine if distraction enterogenesis using self-expanding polycaprolactone (PCL) springs is a potential therapy for short bowel syndrome. Sustained release basic fibroblast growth factor (bFGF) microspheres have been shown to induce angiogenesis and intestinal regeneration in tissue engineered scaffolds. We hypothesized that the provision of bFGF-loaded microspheres would increase angiogenesis and thereby enhance the process of enterogenesis. A 10-mm segment of rodent jejunum was isolated and an encapsulated PCL spring inserted. Blank or bFGF-loaded microspheres were delivered to the segment. After 4weeks, jejunal segments were assessed for lengthening, morphology, quantification of blood vessels, and ganglia. Lengthened intestinal segments receiving bFGF microspheres demonstrated significantly increased microvascular density compared to those with blank microspheres. There were also significantly more submucosal and myenteric ganglia in the segments that received bFGF microspheres. Segments achieved similar lengthening and final muscular thickness in both blank and bFGF groups, but the bFGF microsphere caused a significant increase in luminal diameter of the jejunal segment. Sustained release bFGF microspheres enhanced distraction enterogenesis through improved vascularity. The synergy of growth factors such as bFGF with distraction enterogenesis may yield improved results for the future treatment of patients with short bowel syndrome. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Development and evaluation of floating microspheres of curcumin in ...

    African Journals Online (AJOL)

    Purpose: To prepare and evaluate floating microspheres of curcumin for prolonged gastric residence and to study their effect on alloxan-induced diabetic rats. Methods: Floating microsphere were prepared by emulsion-solvent diffusion method, using hydroxylpropyl methylcellulose, chitosan and Eudragit S 100 polymer in ...

  4. Development and Evaluation of Floating Microspheres of Curcumin ...

    African Journals Online (AJOL)

    Purpose: To prepare and evaluate floating microspheres of curcumin for prolonged gastric residence time and increased drug bioavailability. Methods: Floating microsphere were prepared by emulsion solvent diffusion method, using hydroxylpropyl methylcellulose (HPMC), ethyl cellulose (EC), Eudragit S 100 polymer in ...

  5. Study of the element distribution into the Yttrium glass microspheres

    International Nuclear Information System (INIS)

    Garibov, A.A.; Ghahramani, M.R.; Agayev, T.N.

    2010-01-01

    Full text : Yttrium-90 microspheres administered via the hepatic artery has been used for the treatment of unresectable primary or metastatic cancer in the liver. Y-90 is a pure β-emitter and emits β-particles to decay to stable Zr-89 having peak energy of 2.28 MeV and an average energy of about 0.94 MeV. The dosimetery of low-energy β-sources is inherently complicated due to the sharp dose gradients and the limited range in tissue of the β-particles. The distribution of elements within the microspheres can be effective in the dosimetery. So in this study there was a full focus on the theme of distribution of elements into the microspheres. The quantitative analysis of the microstructure of microspheres is able, by the use of SEM mapping where the topographical analysis of microspheres cross sections is given. There has been shown the EDS maps of Azar sphere (yttrium aluminum silicate) microspheres. The EDS map indicated the distribution of the Y, Si, O, and Al elements into the microspheres at cross section. SEM/EDS line scan techniques was employed for determination of the elemental redistribution across the cross section microspheres for silicon, yttrium, aluminum and oxygen element. There is also a line scan with SEM-EDX was shown along the cross section of Azar sphere sample. The results of the scan showing the variations of concentrations of Si, Y, O and Al are shown in this article.

  6. Development and Evaluation of Floating Microspheres of Curcumin

    African Journals Online (AJOL)

    The shape and surface morphology of the microspheres were characterised by optical and scanning electron microscopy. Result: The floating microspheres showed particle size, buoyancy, drug entrapment efficiency and yield in the ranges of 251 - 387 µm, 74.6 - 90.6 %, and 72.6 - 83.5 %, and 45.5 - 82.0 %, respectively.

  7. Fabrication of polystyrene hollow microspheres as laser fusion ...

    Indian Academy of Sciences (India)

    Inertial confinement fusion, frequently referred to as ICF, inertial fusion, or laser fusion, is a means of producing energy by imploding small hollow microspheres containing thermonuclear fusion fuel. Polymer microspheres, which are used as fuel containers, can be produced by solution-based micro-encapsulation technique ...

  8. Studies of the pulmonary circulation with radioactive microspheres

    International Nuclear Information System (INIS)

    Wagner, H.N. Jr.; James, A.E. Jr.

    1972-01-01

    The use of 99 /sup m/Tc-albumin microspheres to assess the pulmonary circulation has important clinical utility. Particle distribution of injected microspheres accurately reflects regional pulmonary distribution. The value of this diagnostic technique in patients with pulmonary edema, lung neoplasms, and congenital cardiac malformations is emphasized. (U.S.)

  9. Formulation and Optimization of Celecoxib-Loaded Microspheres ...

    African Journals Online (AJOL)

    Purpose: To employ response surface methodology (RSM) for statistical optimization of formulation factors in the preparation of celecoxib-loaded microspheres. Methods: Celecoxib microspheres were prepared by solvent evaporation method. Biodegradable/biocompatible polymers, Eudragit L-100 and polyvinyl ...

  10. Preparation of magnetite-dextran microspheres by ultrasonication

    Energy Technology Data Exchange (ETDEWEB)

    Xia Zefeng [Tongji Medical College, Huazhong University of Science and Technology, Laparoscopy Centre, Xiehe Hospital, 1227 Jiefang Road, Wuhan, Hubei 430022 (China)]. E-mail: xiazefeng@sina.com; Wang Guobin [Tongji Medical College, Huazhong University of Science and Technology, Laparoscopy Centre, Xiehe Hospital, 1227 Jiefang Road, Wuhan, Hubei 430022 (China); Tao Kaixiong [Tongji Medical College, Huazhong University of Science and Technology, Laparoscopy Centre, Xiehe Hospital, 1227 Jiefang Road, Wuhan, Hubei 430022 (China); Li Jianxing [Department of Biomedical Engineering, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030 (China)

    2005-05-15

    An improved method of preparing magnetite-dextran microspheres by ultrasonication is proposed. Several parameters were evaluated and the characteristics of the microspheres investigated by scanning electron microscope (SEM), atomic force microscope (AFM), particle size analyzer and magnetometer. The results show that the initial Fe/dextran ratio is the most effective parameter for both the size and the magnetic properties.

  11. Pectin/zein microspheres as a sustained drug delivery system

    Science.gov (United States)

    A series of microspheres were prepared from pectins and corn proteins from various sources in the presence of the divalent ions calcium or zinc. The results showed that the yield of microsphere and the efficiency of drug incorporation were dependent on the type and ratio of biopolymers, the size of ...

  12. The clearance of albumin microspheres from an intramuscular injection site

    International Nuclear Information System (INIS)

    Mills, S.N.; Davis, S.S.; Frier, M.; Hardy, J.G.; Wilson, C.G.

    1982-01-01

    Human serum albumin microspheres of three different diameters were radiolabelled with indium-111, and a suspension injected into rabbit thigh muscle. Clearance from the intramuscular site was monitored for 2 weeks using gamma scintigraphy. The clearance rates were compared with the injection site clearance of non-biodegradable polystyrene microspheres. (U.K.)

  13. Optimization of sustained release aceclofenac microspheres using response surface methodology

    International Nuclear Information System (INIS)

    Deshmukh, Rameshwar K.; Naik, Jitendra B.

    2015-01-01

    Polymeric microspheres containing aceclofenac were prepared by single emulsion (oil-in-water) solvent evaporation method using response surface methodology (RSM). Microspheres were prepared by changing formulation variables such as the amount of Eudragit® RS100 and the amount of polyvinyl alcohol (PVA) by statistical experimental design in order to enhance the encapsulation efficiency (E.E.) of the microspheres. The resultant microspheres were evaluated for their size, morphology, E.E., and in vitro drug release. The amount of Eudragit® RS100 and the amount of PVA were found to be significant factors respectively for determining the E.E. of the microspheres. A linear mathematical model equation fitted to the data was used to predict the E.E. in the optimal region. Optimized formulation of microspheres was prepared using optimal process variables setting in order to evaluate the optimization capability of the models generated according to IV-optimal design. The microspheres showed high E.E. (74.14 ± 0.015% to 85.34 ± 0.011%) and suitably sustained drug release (minimum; 40% to 60%; maximum) over a period of 12 h. The optimized microspheres formulation showed E.E. of 84.87 ± 0.005 with small error value (1.39). The low magnitudes of error and the significant value of R 2 in the present investigation prove the high prognostic ability of the design. The absence of interactions between drug and polymers was confirmed by Fourier transform infrared (FTIR) spectroscopy. Differential scanning calorimetry (DSC) and X-ray powder diffractometry (XRPD) revealed the dispersion of drug within microspheres formulation. The microspheres were found to be discrete, spherical with smooth surface. The results demonstrate that these microspheres could be promising delivery system to sustain the drug release and improve the E.E. thus prolong drug action and achieve the highest healing effect with minimal gastrointestinal side effects. - Highlights: • Aceclofenac microspheres were

  14. Optimization of sustained release aceclofenac microspheres using response surface methodology

    Energy Technology Data Exchange (ETDEWEB)

    Deshmukh, Rameshwar K.; Naik, Jitendra B., E-mail: jitunaik@gmail.com

    2015-03-01

    Polymeric microspheres containing aceclofenac were prepared by single emulsion (oil-in-water) solvent evaporation method using response surface methodology (RSM). Microspheres were prepared by changing formulation variables such as the amount of Eudragit® RS100 and the amount of polyvinyl alcohol (PVA) by statistical experimental design in order to enhance the encapsulation efficiency (E.E.) of the microspheres. The resultant microspheres were evaluated for their size, morphology, E.E., and in vitro drug release. The amount of Eudragit® RS100 and the amount of PVA were found to be significant factors respectively for determining the E.E. of the microspheres. A linear mathematical model equation fitted to the data was used to predict the E.E. in the optimal region. Optimized formulation of microspheres was prepared using optimal process variables setting in order to evaluate the optimization capability of the models generated according to IV-optimal design. The microspheres showed high E.E. (74.14 ± 0.015% to 85.34 ± 0.011%) and suitably sustained drug release (minimum; 40% to 60%; maximum) over a period of 12 h. The optimized microspheres formulation showed E.E. of 84.87 ± 0.005 with small error value (1.39). The low magnitudes of error and the significant value of R{sup 2} in the present investigation prove the high prognostic ability of the design. The absence of interactions between drug and polymers was confirmed by Fourier transform infrared (FTIR) spectroscopy. Differential scanning calorimetry (DSC) and X-ray powder diffractometry (XRPD) revealed the dispersion of drug within microspheres formulation. The microspheres were found to be discrete, spherical with smooth surface. The results demonstrate that these microspheres could be promising delivery system to sustain the drug release and improve the E.E. thus prolong drug action and achieve the highest healing effect with minimal gastrointestinal side effects. - Highlights: • Aceclofenac microspheres

  15. Super-Resolution Real Imaging in Microsphere-Assisted Microscopy.

    Directory of Open Access Journals (Sweden)

    Hok Sum Sam Lai

    Full Text Available Microsphere-assisted microscopy has received a lot of attention recently due to its simplicity and its capability to surpass the diffraction limit. However, to date, sub-diffraction-limit features have only been observed in virtual images formed through the microspheres. We show that it is possible to form real, super-resolution images using high-refractive index microspheres. Also, we report on how changes to a microsphere's refractive index and size affect image formation and planes. The relationship between the focus position and the additional magnification factor is also investigated using experimental and theoretical methods. We demonstrate that such a real imaging mode, combined with the use of larger microspheres, can enlarge sub-diffraction-limit features up to 10 times that of wide-field microscopy's magnification with a field-of-view diameter of up to 9 μm.

  16. Synthesis and characterization of magnetic poly(glycidyl methacrylate) microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Horak, Daniel [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovskeho Sq. 2, 162 06 Prague 6 (Czech Republic)]. E-mail: horak@imc.cas.cz; Petrovsky, Eduard [Geophysical Institute, Academy of Sciences of the Czech Republic, Bocni II/1401, 141 31 Prague 4 (Czech Republic); Kapicka, Ales [Geophysical Institute, Academy of Sciences of the Czech Republic, Bocni II/1401, 141 31 Prague 4 (Czech Republic); Frederichs, Theodor [University of Bremen, Department of Geosciences, GEO I, Klagenfurter Strasse, 28359 Bremen (Germany)

    2007-04-15

    Magnetic nanoparticles encapsulated in poly(glycidyl methacrylate) microspheres were prepared and their detailed structural and magnetic characteristics given. Iron oxide nanoparticles were obtained by chemical coprecipitation of Fe(II) and Fe(III) salts and stabilized with dextran, (carboxymethyl)dextran or tetramethylammonium hydroxide. The microspheres were prepared by emulsion or dispersion polymerization of glycidyl methacrylate in the presence of ferrofluid. The microspheres were uniform both in shape and usually also in size; their size distribution was narrow. All the magnetic parameters confirm superparamagnetic nature of the microspheres. Blocking temperature was not observed, suggesting the absence of magnetic interactions at low temperatures. This is most probably caused by complete encapsulation and the absence of agglomeration. Such microspheres can be used in biomedical applications.

  17. Textiles with gallic acid microspheres: in vitro release characteristics.

    Science.gov (United States)

    Martí, Meritxell; Martínez, Vanessa; Carreras, Núria; Alonso, Cristina; Lis, Manuel José; Parra, José Luis; Coderch, Luisa

    2014-01-01

    Abstract The aim of this study was to demonstrate the skin penetration of an antioxidant, gallic acid (GA), encapsulated in poly-ε-caprolactone (PCL) microspheres and applied onto textile fabrics, by a specific in vitro percutaneous absorption methodology. Two techniques (particle size distribution and FTIR) were used to characterise the microspheres obtained. The amount of GA-loaded microspheres present in the biofunctional textiles was established before their use as a textile drug delivery system. More absorption and desorption of microspheres with GA for the polyamide fabric were found in comparison with cotton fabric. The percutaneous absorption results indicated that the skin penetration of GA released from PCL-microspheres that were applied directly to the skin was higher than when GA was embedded within biofunctional textiles, in conclusion, an interesting reservoir effect may be promoted when biofunctional textiles were used.

  18. Labelling of silica microspheres with fluorescent lanthanide-doped LaF3 nanocrystals

    International Nuclear Information System (INIS)

    Zhang Yong; Lu Meihua

    2007-01-01

    Fluorescent microspheres have been demonstrated to be useful in a variety of biological applications. Fluorescent silica or polymer microspheres have been produced by incorporation of chromophores into the microspheres, which usually produces microspheres with nonuniform sizes and reduced fluorescence. Here we present a simple and straightforward method to produce silica microspheres with fluorescent lanthanide-doped LaF 3 nanocrystals grown on the surface. LaF 3 nanocrystals are in situ grown on silica microspheres of different sizes to form a raspberry-like structure. The microspheres exhibit strong fluorescence and the colour could be altered by changing the lanthanide ions doped in LaF 3 nanocrystals

  19. Magnetic-luminescent YbPO4:Er,Dy microspheres designed for tumor theranostics with synergistic effect of photodynamic therapy and chemotherapy.

    Science.gov (United States)

    Wang, Wei; Xu, Dong; Wei, Xiaojun; Chen, Kezheng

    2014-01-01

    In this paper, magnetic and fluorescent bifunctional YbPO4:Er,Dy microspheres were synthesized via a simple solvothermal method. The prepared microspheres exposed to 980 nm near-infrared (NIR) laser light emitted bright upconversion fluorescence (450-570 nm) after calcination at high temperatures (>800°C). Results of magnetic resonance studies demonstrated that the YbPO4:Er,Dy microspheres are more suitable to be used as a transverse relaxation time (negative) contrast magnetic resonance imaging agent. The microspheres successfully entered the human hepatocellular carcinoma cells and presented low toxicity. A well-selected photodynamic therapy (PDT) drug, merocyanine 540 (MC540) with an ultraviolet-visible spectroscopy absorption maximum of 540 nm, was loaded onto the microspheres to obtain YbPO4:Er,Dy-MC540. Since the upconversion fluorescence emitting from the microspheres could be absorbed by MC540 with a small absorption/emission disparity, YbPO4:Er,Dy-MC540 could kill the hepatocellular carcinoma cells via PDT mechanism effectively. In other words, being upconverting particles, the prepared microspheres acted as light transducers in the NIR light-triggered PDT process. A chemotherapy drug, doxorubicin, was further loaded onto YbPO4:Er,Dy-MC540 to achieve enhanced antitumor effect based on synergistic therapeutic efficacy of PDT and chemotherapy. It is expected that the prepared YbPO4:Er,Dy microspheres have applications in tumor theranostics including magnetic-fluorescent bimodal imaging and NIR light-triggered PDT.

  20. Comparative DNA isolation behaviours of silica and polymer based sorbents in batch fashion: monodisperse silica microspheres with bimodal pore size distribution as a new sorbent for DNA isolation.

    Science.gov (United States)

    Günal, Gülçin; Kip, Çiğdem; Eda Öğüt, S; İlhan, Hasan; Kibar, Güneş; Tuncel, Ali

    2018-02-01

    Monodisperse silica microspheres with bimodal pore-size distribution were proposed as a high performance sorbent for DNA isolation in batch fashion under equilibrium conditions. The proposed sorbent including both macroporous and mesoporous compartments was synthesized 5.1 μm in-size, by a "staged shape templated hydrolysis and condensation method". Hydrophilic polymer based sorbents were also obtained in the form of monodisperse-macroporous microspheres ca 5.5 μm in size, with different functionalities, by a developed "multi-stage microsuspension copolymerization" technique. The batch DNA isolation performance of proposed material was comparatively investigated using polymer based sorbents with similar morphologies. Among all sorbents tried, the best DNA isolation performance was achieved with the monodisperse silica microspheres with bimodal pore size distribution. The collocation of interconnected mesoporous and macroporous compartments within the monodisperse silica microspheres provided a high surface area and reduced the intraparticular mass transfer resistance and made easier both the adsorption and desorption of DNA. Among the polymer based sorbents, higher DNA isolation yields were achieved with the monodisperse-macroporous polymer microspheres carrying trimethoxysilyl and quaternary ammonium functionalities. However, batch DNA isolation performances of polymer based sorbents were significantly lower with respect to the silica microspheres.

  1. Carbon dioxide and climate. [Appendix includes names and addresses of the Principal Investigators for the research projects funded in FY1991

    Energy Technology Data Exchange (ETDEWEB)

    1991-10-01

    Global climate change is a serious environmental concern, and the US has developed An Action Agenda'' to deal with it. At the heart of the US effort is the US Global Change Research Program (USGCRP), which has been developed by the Committee on Earth and Environmental Sciences (CEES) of the Federal Coordinating Council for Sciences, Engineering, and Technology (FCCSET). The USGCRP will provide the scientific basis for sound policy making on the climate-change issue. The DOE contribution to the USGCRP is the Carbon Dioxide Research Program, which now places particular emphasis on the rapid improvement of the capability to predict global and regional climate change. DOE's Carbon Dioxide Research Program has been addressing the carbon dioxide-climate change connection for more than twelve years and has provided a solid scientific foundation for the USGCRP. The expansion of the DOE effort reflects the increased attention that the Department has placed on the issue and is reflected in the National Energy Strategy (NES) that was released in 1991. This Program Summary describes projects funded by the Carbon Dioxide Research Program during FY 1991 and gives a brief overview of objectives, organization, and accomplishments. The Environmental Sciences Division of the Office of Health and Environmental Research, Office of Energy Research supports a Carbon Dioxide Research Program to determine the scientific linkage between the rise of greenhouse gases in the atmosphere, especially carbon dioxide, and climate and vegetation change. One facet is the Core CO{sub 2} Program, a pioneering program that DOE established more than 10 years ago to understand and predict the ways that fossil-fuel burning could affect atmospheric CO{sub 2} concentration, global climate, and the Earth's biosphere. Major research areas are: global carbon cycle; climate detection and models of climate change; vegetation research; resource analysis; and, information and integration.

  2. Constraining carbonaceous aerosol sources in a receptor model by including 14C data with redox species, organic tracers, and elemental/organic carbon measurements

    Science.gov (United States)

    Piletic, Ivan R.; Offenberg, John H.; Olson, David A.; Jaoui, Mohammed; Krug, Jonathan; Lewandowski, Michael; Turlington, John M.; Kleindienst, Tadeusz E.

    2013-12-01

    Sources of carbonaceous PM2.5 were quantified in downtown Cleveland, OH and Chippewa Lake, OH located ∼40 miles southwest of Cleveland during the Cleveland Multiple Air Pollutant Study (CMAPS). PM2.5 filter samples were collected daily during July-August 2009 and February 2010 to establish the seasonal emission patterns from local and regional sources. Radiocarbon (14C), redox species (NOx, SO2 and ozone), 28 primary and secondary organic aerosol tracers, elemental carbon (EC) and organic carbon (OC) measurements were analyzed using the EPA Positive Matrix Factorization (PMF) model to apportion carbonaceous aerosol sources. Five sources were identified at each site: mobile sources, fossil fuel combustion from fuels containing sulfur, local biomass combustion, other combustion (regional biomass, waste, meat, coal), and secondary organic aerosol (SOA). 14C data were incorporated in the PMF analysis as a novel method to obtain the modern carbon fraction (fmod) of each source individually which aided all factor interpretations. SOA was the principal carbon source during summer as shown by the PMF analysis and a separate tracer based mass fraction method while biomass burning and other combustion sources were dominant in winter. Elevated levels of EC and fossilized carbon in downtown Cleveland are primarily attributed to increased mobile source and coal combustion emissions.

  3. Randomized Trial of Hepatic Artery Embolization for Hepatocellular Carcinoma Using Doxorubicin-Eluting Microspheres Compared With Embolization With Microspheres Alone

    Science.gov (United States)

    Do, Richard K.; Gonen, Mithat; Covey, Anne M.; Getrajdman, George I.; Sofocleous, Constantinos T.; Jarnagin, William R.; D’Angelica, Michael I.; Allen, Peter J.; Erinjeri, Joseph P.; Brody, Lynn A.; O’Neill, Gerald P.; Johnson, Kristian N.; Garcia, Alessandra R.; Beattie, Christopher; Zhao, Binsheng; Solomon, Stephen B.; Schwartz, Lawrence H.; DeMatteo, Ronald; Abou-Alfa, Ghassan K.

    2016-01-01

    Purpose Transarterial chemoembolization is accepted therapy for hepatocellular carcinoma (HCC). No randomized trial has demonstrated superiority of chemoembolization compared with embolization, and the role of chemotherapy remains unclear. This randomized trial compares the outcome of embolization using microspheres alone with chemoembolization using doxorubicin-eluting microspheres. Materials and Methods At a single tertiary referral center, patients with HCC were randomly assigned to embolization with microspheres alone (Bead Block [BB]) or loaded with doxorubicin 150 mg (LC Bead [LCB]). Random assignment was stratified by number of embolizations to complete treatment, and assignments were generated by permuted blocks in the institutional database. The primary end point was response according to RECIST 1.0 (Response Evaluation Criteria in Solid Tumors) using multiphase computed tomography 2 to 3 weeks post-treatment and then at quarterly intervals, with the reviewer blinded to treatment allocation. Secondary objectives included safety and tolerability, time to progression, progression-free survival, and overall survival. This trial is currently closed to accrual. Results Between December 2007 and April 2012, 101 patients were randomly assigned: 51 to BB and 50 to LCB. Demographics were comparable: median age, 67 years; 77% male; and 22% Barcelona Clinic Liver Cancer stage A and 78% stage B or C. Adverse events occurred with similar frequency in both groups: BB, 19 of 51 patients (38%); LCB, 20 of 50 patients (40%; P = .48), with no difference in RECIST response: BB, 5.9% versus LCB, 6.0% (difference, −0.1%; 95% CI, −9% to 9%). Median PFS was 6.2 versus 2.8 months (hazard ratio, 1.36; 95% CI, 0.91 to 2.05; P = .11), and overall survival, 19.6 versus 20.8 months (hazard ratio, 1.11; 95% CI, 0.71 to 1.76; P = .64) for BB and LCB, respectively. Conclusion There was no apparent difference between the treatment arms. These results challenge the use of doxorubicin

  4. Outpatient single-session yttrium-90 glass microsphere radioembolization.

    Science.gov (United States)

    Gates, Vanessa L; Marshall, Karen G; Salzig, Krystina; Williams, Melissa; Lewandowski, Robert J; Salem, Riad

    2014-02-01

    To investigate the feasibility of yttrium-90 ((90)Y) glass microsphere radioembolization (including angiography, lung shunt assessment, and treatment) as a single-session, outpatient procedure. Between January 2008 and June 2013, 14 patients underwent outpatient, single-session radioembolization with (90)Y glass microspheres. As part of the routine diagnostic work-up, all patients underwent either computed tomography (CT) or magnetic resonance imaging of the liver with three-dimensional analysis and had laboratory results forwarded to our center for confirmation of candidacy before treatment. On treatment day, all patients underwent planning mesenteric angiography with flat panel cone-beam CT imaging. Patients were administered 33-85 MBq of technetium-99m macroaggregated albumin ((99m)Tc-MAA) via a microcatheter positioned in a hepatic artery supplying the tumor of interest. Planar scintigraphy was initiated within 2 hours after the administration of (99m)Tc-MAA and lung shunt fraction was determined. Final dosimetry calculations were performed while the patient was being transferred back from nuclear medicine to interventional radiology. All patients successfully underwent planning angiography with administration of (99m)Tc-MAA and (90)Y radioembolization as a single-session treatment. There were no reportable or recordable medical events; treatment was carried out to the desired dose in all cases. The mean total procedure time was 2.70 hours ± 0.72 (range, 1.63-3.97 h). This study reports a novel proof of concept for performing radioembolization in a single-session setting. By using the described method, time between initial clinical assessments and radioembolization treatment is decreased, and costs are minimized. © 2014 Published by SIR on behalf of SIR.

  5. Measurement of thermal diffusivity of depleted uranium metal microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Humrickhouse-Helmreich, Carissa J., E-mail: carissahelmreich@tamu.edu [Texas A and M University, Department of Nuclear Engineering, 337 Zachry Engineering Center, 3133 TAMU, College Station, TX 77843 (United States); Corbin, Rob, E-mail: rcorbin@terrapower.com [TerraPower, LLC, 330 120th Ave NE, Suite 100, Bellevue, WA 98005 (United States); McDeavitt, Sean M., E-mail: mcdeavitt@tamu.edu [Texas A and M University, Department of Nuclear Engineering, 337 Zachry Engineering Center, 3133 TAMU, College Station, TX 77843 (United States)

    2014-03-15

    The high void space of nuclear fuels composed of homogeneous uranium metal microspheres may allow them to achieve ultra-high burnup by accommodating fuel swelling and reducing fuel/cladding interactions; however, the relatively low thermal conductivity of microsphere nuclear fuels may limit their application. To support the development of microsphere nuclear fuels, an apparatus was designed in a glovebox and used to measure the apparent thermal diffusivity of a packed bed of depleted uranium (DU) microspheres with argon fill in the void spaces. The developed Crucible Heater Test Assembly (CHTA) recorded radial temperature changes due to an initial heat pulse from a central thin-diameter cartridge heater. Using thermocouple positions and time–temperature data, the apparent thermal diffusivity was calculated. The thermal conductivity of the DU microspheres was calculated based on the thermal diffusivity from the CHTA, known material densities and specific heat capacities, and an assumed 70% packing density based on prior measurements. Results indicate that DU metal microspheres have very low thermal conductivity, relative to solid uranium metal, and rapidly form an oxidation layer even in a low oxygen environment. At 500 °C, the thermal conductivity of the DU metal microsphere bed was 0.431 ± 0.0560 W/m-K compared to the literature value of approximately 32 W/m-K for solid uranium metal.

  6. Measurement of thermal diffusivity of depleted uranium metal microspheres

    Science.gov (United States)

    Humrickhouse-Helmreich, Carissa J.; Corbin, Rob; McDeavitt, Sean M.

    2014-03-01

    The high void space of nuclear fuels composed of homogeneous uranium metal microspheres may allow them to achieve ultra-high burnup by accommodating fuel swelling and reducing fuel/cladding interactions; however, the relatively low thermal conductivity of microsphere nuclear fuels may limit their application. To support the development of microsphere nuclear fuels, an apparatus was designed in a glovebox and used to measure the apparent thermal diffusivity of a packed bed of depleted uranium (DU) microspheres with argon fill in the void spaces. The developed Crucible Heater Test Assembly (CHTA) recorded radial temperature changes due to an initial heat pulse from a central thin-diameter cartridge heater. Using thermocouple positions and time-temperature data, the apparent thermal diffusivity was calculated. The thermal conductivity of the DU microspheres was calculated based on the thermal diffusivity from the CHTA, known material densities and specific heat capacities, and an assumed 70% packing density based on prior measurements. Results indicate that DU metal microspheres have very low thermal conductivity, relative to solid uranium metal, and rapidly form an oxidation layer even in a low oxygen environment. At 500 °C, the thermal conductivity of the DU metal microsphere bed was 0.431 ± 0.0560 W/m-K compared to the literature value of approximately 32 W/m-K for solid uranium metal.

  7. Measurement of thermal diffusivity of depleted uranium metal microspheres

    International Nuclear Information System (INIS)

    Humrickhouse-Helmreich, Carissa J.; Corbin, Rob; McDeavitt, Sean M.

    2014-01-01

    The high void space of nuclear fuels composed of homogeneous uranium metal microspheres may allow them to achieve ultra-high burnup by accommodating fuel swelling and reducing fuel/cladding interactions; however, the relatively low thermal conductivity of microsphere nuclear fuels may limit their application. To support the development of microsphere nuclear fuels, an apparatus was designed in a glovebox and used to measure the apparent thermal diffusivity of a packed bed of depleted uranium (DU) microspheres with argon fill in the void spaces. The developed Crucible Heater Test Assembly (CHTA) recorded radial temperature changes due to an initial heat pulse from a central thin-diameter cartridge heater. Using thermocouple positions and time–temperature data, the apparent thermal diffusivity was calculated. The thermal conductivity of the DU microspheres was calculated based on the thermal diffusivity from the CHTA, known material densities and specific heat capacities, and an assumed 70% packing density based on prior measurements. Results indicate that DU metal microspheres have very low thermal conductivity, relative to solid uranium metal, and rapidly form an oxidation layer even in a low oxygen environment. At 500 °C, the thermal conductivity of the DU metal microsphere bed was 0.431 ± 0.0560 W/m-K compared to the literature value of approximately 32 W/m-K for solid uranium metal

  8. Carbon Cryogel Silicon Composite Anode Materials for Lithium Ion Batteries

    Science.gov (United States)

    Woodworth James; Baldwin, Richard; Bennett, William

    2010-01-01

    A variety of materials are under investigation for use as anode materials in lithium-ion batteries, of which, the most promising are those containing silicon. 10 One such material is a composite formed via the dispersion of silicon in a resorcinol-formaldehyde (RF) gel followed by pyrolysis. Two silicon-carbon composite materials, carbon microspheres and nanofoams produced from nano-phase silicon impregnated RF gel precursors have been synthesized and investigated. Carbon microspheres are produced by forming the silicon-containing RF gel into microspheres whereas carbon nano-foams are produced by impregnating carbon fiber paper with the silicon containing RF gel to create a free standing electrode. 1-4,9 Both materials have demonstrated their ability to function as anodes and utilize the silicon present in the material. Stable reversible capacities above 400 mAh/g for the bulk material and above 1000 mAh/g of Si have been observed.

  9. Thyroid artery embolization with microspheres for hyperthyroidism

    International Nuclear Information System (INIS)

    Du Yahui; Zhong Chenfu; Chen Weijun; Zhang Ying; Luo Jun; Li Xiaoguang; Cao Junjie; Gan Changli; Cao Junjie; Gan Changli

    2006-01-01

    Objective: To evaluate the method and efficacy of thyroid artery embolization as a new therapy for hyperthyroidism. Methods: Thirteen patients with hyperthyroidism underwent selective thyroid artery embolization. Totally 25 thyroid arteries were embolized with microspheres. The indications for this therapy were as followings: 1) To give hyperthyroid patients having an alternative for surgical and 131 I treatment, and 2) To provide a new method for those clinically being difficult to get control with medicine. Results: Serum level of thyroid hormones dropped significantly[T3 from 2.84-9.0 ng/ml to 0.8-2.2 ng/ml, T4 from 162.9-277.2 ng/ml to 50-126 ng/ml] and symptoms of hyperthyroidism were under control in 12 patients within 1 month after the embolization. One patient remained no change 1 month later and refused to be embolized again. The symptoms of twelve patients were effectively controlled through low dose antithyroid medication for more than 6 months follow up with no serious complications. Conclusion: Thyroid artery embolization with microspheres is an effective alternative for surgical and 131 I treatment of hyperthyroidism. (authors)

  10. Preparation and properties of polyvinyl alcohol microspheres

    International Nuclear Information System (INIS)

    Campbell, J.H.; Grens, J.Z.; Poco, J.F.; Ives, B.H.

    1986-06-01

    Polyvinyl alcohol (PVA) microspheres, having a size range of ∼150- to 250-μm diameter with 1- to 5-μm wall thickness, have been fabricated using a solution droplet technique. The spheres were developed for possible use on the Lawrence Livermore National Laboratory (LLNL) Inertial Confinement Fusion (ICF) Program. PVA, a polymer chosen based on earlier survey work carried out at KMS Fusion, Inc., has good strength, low hydrogen permeability, is optically transparent, and water soluble. The latter property makes it safe and easy to use in our droplet generator system. A unique dual-orifice droplet generator was used to prepare the spheres. The droplet generator operating conditions and the column processing parameters were chosen using results from our 1-D model calculations as a guide. The polymer microsphere model is an extension of the model we developed to support the glass sphere production. After preparation, the spheres were physically characterized for surface quality, sphericity, wall thickness (and uniformity), and size. We also determined the buckling pressure for both uncoated and CH-coated spheres. Radiation stability to beta decay (from tritium) was evaluated by exposing the spheres to a 7-keV electron beam. The results from these and other physical property measurements are presented in this report

  11. Development of prilling process for biodegradable microspheres through experimental designs.

    Science.gov (United States)

    Fabien, Violet; Minh-Quan, Le; Michelle, Sergent; Guillaume, Bastiat; Van-Thanh, Tran; Marie-Claire, Venier-Julienne

    2016-02-10

    The prilling process proposes a microparticle formulation easily transferable to the pharmaceutical production, leading to monodispersed and highly controllable microspheres. PLGA microspheres were used for carrying an encapsulated protein and adhered stem cells on its surface, proposing a tool for regeneration therapy against injured tissue. This work focused on the development of the production of PLGA microspheres by the prilling process without toxic solvent. The required production quality needed a complete optimization of the process. Seventeen parameters were studied through experimental designs and led to an acceptable production. The key parameters and mechanisms of formation were highlighted. Copyright © 2015. Published by Elsevier B.V.

  12. Novel synthesis strategy for composite hydrogel of collagen/hydroxyapatite-microsphere originating from conversion of CaCO3 templates

    Science.gov (United States)

    Wei, Qingrong; Lu, Jian; Wang, Qiaoying; Fan, Hongsong; Zhang, Xingdong

    2015-03-01

    Inspired by coralline-derived hydroxyapatite, we designed a methodological route to synthesize carbonated-hydroxyapatite microspheres from the conversion of CaCO3 spherulite templates within a collagen matrix under mild conditions and thus constructed the composite hydrogel of collagen/hydroxyapatite-microspheres. Fourier transform infrared spectroscopy (FTIR) and x-ray diffraction (XRD) were employed to confirm the successful generation of the carbonated hydroxyapatite phase originating from CaCO3, and the ratios of calcium to phosphate were tracked over time. Variations in the weight portion of the components in the hybrid gels before and after the phase transformation of the CaCO3 templates were identified via thermogravimetric analysis (TGA). Scanning electron microscopy (SEM) shows these composite hydrogels have a unique multiscale microstructure consisting of a collagen nanofibril network and hydroxyapatite microspheres. The relationship between the hydroxyapatite nanocrystals and the collagen fibrils was revealed by transmission electron microscopy (TEM) in detail, and the selected area electron diffraction (SAED) pattern further confirmed the results of the XRD analyses which show the typical low crystallinity of the generated hydroxyapatite. This smart synthesis strategy achieved the simultaneous construction of microscale hydroxyapatite particles and collagen fibrillar hydrogel, and appears to provide a novel route to explore an advanced functional hydrogel materials with promising potentials for applications in bone tissue engineering and reconstruction medicine.

  13. Novel synthesis strategy for composite hydrogel of collagen/hydroxyapatite-microsphere originating from conversion of CaCO3 templates.

    Science.gov (United States)

    Wei, Qingrong; Lu, Jian; Wang, Qiaoying; Fan, Hongsong; Zhang, Xingdong

    2015-03-20

    Inspired by coralline-derived hydroxyapatite, we designed a methodological route to synthesize carbonated-hydroxyapatite microspheres from the conversion of CaCO3 spherulite templates within a collagen matrix under mild conditions and thus constructed the composite hydrogel of collagen/hydroxyapatite-microspheres. Fourier transform infrared spectroscopy (FTIR) and x-ray diffraction (XRD) were employed to confirm the successful generation of the carbonated hydroxyapatite phase originating from CaCO3, and the ratios of calcium to phosphate were tracked over time. Variations in the weight portion of the components in the hybrid gels before and after the phase transformation of the CaCO3 templates were identified via thermogravimetric analysis (TGA). Scanning electron microscopy (SEM) shows these composite hydrogels have a unique multiscale microstructure consisting of a collagen nanofibril network and hydroxyapatite microspheres. The relationship between the hydroxyapatite nanocrystals and the collagen fibrils was revealed by transmission electron microscopy (TEM) in detail, and the selected area electron diffraction (SAED) pattern further confirmed the results of the XRD analyses which show the typical low crystallinity of the generated hydroxyapatite. This smart synthesis strategy achieved the simultaneous construction of microscale hydroxyapatite particles and collagen fibrillar hydrogel, and appears to provide a novel route to explore an advanced functional hydrogel materials with promising potentials for applications in bone tissue engineering and reconstruction medicine.

  14. Fabricating solid carbon porous electrodes from powders

    Science.gov (United States)

    Kaschmitter, James L.; Tran, Tri D.; Feikert, John H.; Mayer, Steven T.

    1997-01-01

    Fabrication of conductive solid porous carbon electrodes for use in batteries, double layer capacitors, fuel cells, capacitive dionization, and waste treatment. Electrodes fabricated from low surface area (Electrodes having a higher surface area, fabricated from powdered carbon blacks, such as carbon aerogel powder, carbon aerogel microspheres, activated carbons, etc. yield high conductivity carbon compositives with excellent double layer capacity, and can be used in double layer capacitors, or for capacitive deionization and/or waste treatment of liquid streams. By adding metallic catalysts to be high surface area carbons, fuel cell electrodes can be produced.

  15. Enhanced Probiotic Potential of Lactobacillus reuteri When Delivered as a Biofilm on Dextranomer Microspheres That Contain Beneficial Cargo

    Science.gov (United States)

    Navarro, Jason B.; Mashburn-Warren, Lauren; Bakaletz, Lauren O.; Bailey, Michael T.; Goodman, Steven D.

    2017-01-01

    As with all orally consumed probiotics, the Gram-positive bacterium Lactobacillus reuteri encounters numerous challenges as it transits through the gastrointestinal tract of the host, including low pH, effectors of the host immune system, as well as competition with commensal and pathogenic bacteria, all of which can greatly reduce the availability of live bacteria for therapeutic purposes. Recently we showed that L. reuteri, when adhered in the form of a biofilm to a semi-permeable biocompatible dextranomer microsphere, reduces the incidence of necrotizing enterocolitis by 50% in a well-defined animal model following delivery of a single prophylactic dose. Herein, using the same semi-permeable microspheres, we showed that providing compounds beneficial to L. reuteri as diffusible cargo within the microsphere lumen resulted in further advantageous effects including glucosyltransferase-dependent bacterial adherence to the microsphere surface, resistance of bound bacteria against acidic conditions, enhanced adherence of L. reuteri to human intestinal epithelial cells in vitro, and facilitated production of the antimicrobial compound reuterin and the anti-inflammatory molecule histamine. These data support continued development of this novel probiotic formulation as an adaptable and effective means for targeted delivery of cargo beneficial to the probiotic bacterium. PMID:28396655

  16. Stimuli-responsive transformation in carbon nanotube/expanding microsphere–polymer composites

    International Nuclear Information System (INIS)

    Loomis, James; Xu Peng; Panchapakesan, Balaji

    2013-01-01

    Our work introduces a class of stimuli-responsive expanding polymer composites with the ability to unidirectionally transform their physical dimensions, elastic modulus, density, and electrical resistance. Carbon nanotubes and core–shell acrylic microspheres were dispersed in polydimethylsiloxane, resulting in composites that exhibit a binary set of material properties. Upon thermal or infrared stimuli, the liquid cores encapsulated within the microspheres vaporize, expanding the surrounding shells and stretching the matrix. The microsphere expansion results in visible dimensional changes, regions of reduced polymeric chain mobility, nanotube tensioning, and overall elastic to plastic-like transformation of the composite. Here, we show composite transformations including macroscopic volume expansion (>500%), density reduction (>80%), and elastic modulus increase (>675%). Additionally, conductive nanotubes allow for remote expansion monitoring and exhibit distinct loading-dependent electrical responses. With the ability to pattern regions of tailorable expansion, strength, and electrical resistance into a single polymer skin, these composites present opportunities as structural and electrical building blocks in smart systems. (paper)

  17. Novel Synthesis of Yttrium Phosphate Microspheres for Radioembolization of Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Kawashita, M; Matsui, N; Li, Z [Department of Biomedical Engineering, Graduate School of Biomedical Engineering, Tohoku University (Japan); Miyazaki, T, E-mail: m-kawa@ecei.tohoku.ac.jp [Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology (Japan)

    2011-10-29

    Chemically durable microspheres containing yttrium and/or phosphorus are useful for intra-arterial radiotherapy. In the present study, we attempted to prepare yttrium phosphate (YPO{sub 4}) microspheres with high chemical durability as well as smooth surface and investigated their chemical durability in simulated body environment. YPO{sub 4} microspheres with smooth surface around 25 {mu}m were successfully obtained, when gelatin droplets containing YPO{sub 4} precursor was cooled to be solidified in water-in-oil emulsion and then heat-treated at 1100 deg. C. The chemical durability of the heat-treated microspheres in simulated body fluid at pH =6 and 7 was high enough for clinical application of radioembolic therapy of cancer.

  18. Properties of rigid polyurethane foams filled with glass microspheres

    Science.gov (United States)

    Yakushin, V.; Bel'kova, L.; Sevastyanova, I.

    2012-11-01

    The effect of hollow glass microspheres with a density of 125 kg/m3 on the properties of low-density (54-90 kg/m3) rigid polyurethane foams is investigated. The thermal expansion coefficient of the foams and their properties in tension and compression in relation to the content of the microspheres (0.5-5 wt.%) are determined. An increase in the characteristics of the material in compression in the foam rise direction with increasing content of filler is revealed. The limiting content of the microspheres above which the mechanical characteristics of the filled foams begin to decrease is found. The distribution of the microspheres in elements of the cellular structure of the polyurethane foams is examined.

  19. Investigation of defects on PAMS microspheres fabricated with microencapsulation method

    International Nuclear Information System (INIS)

    Chen Sufen; Li Bo; Liu Yiyang; Zhang Zhanwen; Qi Xiaobo

    2012-01-01

    Poly-(α-methylstyrene) (PAMS) microspheres were fabricated with W1/O/W2 double emulsion microencapsulation method, and the effects of polyvinylalcohol (PVA) and CaCl 2 weight concentrations and the O/W2 phase ratio on the percentages of defected PAMS microspheres were studied. The weight concentrations of PVA and CaCl 2 and the O/W2 phase ratio in the fabrication process of PAMS microspheres were optimized. The results show that, for the three parameters being 1.0%, 1.5%, and 0.01, respectively, the percentage of the defect-free PAMS microspheres without vacuoles in the shell wall can be up to 60%. (authors)

  20. Facile preparation of hierarchically porous polymer microspheres for superhydrophobic coating

    Science.gov (United States)

    Gao, Jiefeng; Wong, Julia Shuk-Ping; Hu, Mingjun; Li, Wan; Li, Robert. K. Y.

    2013-12-01

    A facile method, i.e., nonsolvent assisted electrospraying, is proposed to fabricate hierarchically porous microspheres. The pore size on the microsphere surface ranges from a few tens to several hundred nanometers. Thermally and nonsolvent induced phase separation as well as breath figure is responsible for the formation of the hierarchical structures with different nano-sized pores. The nonsolvent could not only induce phase separation, but also stabilize the interface between the droplet and air, which can prevent the droplet from strong deformation, and is therefore beneficial to the formation of regular and uniform microspheres. On the other hand, solvent evaporation, polymer diffusion and Coulomb fission during electrospraying influence the morphology of finally obtained products. In this paper, the influence of polymer concentration, the weight ratio between nonsolvent and polymer and the flowing rate on the morphology of the porous microsphere is carefully studied. The hierarchically porous microsphere significantly increases the surface roughness and thus the hydrophobicity, and the contact angle can reach as high as 152.2 +/- 1.2°. This nonsolvent assisted electrospraying opens a new way to fabricate superhydrophobic coating materials.A facile method, i.e., nonsolvent assisted electrospraying, is proposed to fabricate hierarchically porous microspheres. The pore size on the microsphere surface ranges from a few tens to several hundred nanometers. Thermally and nonsolvent induced phase separation as well as breath figure is responsible for the formation of the hierarchical structures with different nano-sized pores. The nonsolvent could not only induce phase separation, but also stabilize the interface between the droplet and air, which can prevent the droplet from strong deformation, and is therefore beneficial to the formation of regular and uniform microspheres. On the other hand, solvent evaporation, polymer diffusion and Coulomb fission during

  1. Application of sustained release microsphere in hypoparathyroidism after thyroid surgery

    Directory of Open Access Journals (Sweden)

    Pan Ming

    2017-01-01

    Full Text Available Hypoparathyroidism (HypoPT is one of the most common complications after thyroid surgery. The parathyroid hormone-controlled delivery system is one of the most significant therapies for hypothyroidism after thyroid and parathyroid surgery. The character of biodegradability and the slow release of PTH of the Sustained release microspheres were widely concerned. The authors present the research progress in sustained release microspheres loaded with PTH from the character, material, fabrication and application.

  2. Formulation and Evaluation of Mucoadhesive Microspheres of Lamivudine

    OpenAIRE

    Aliya Parveen; Iizhar Ahmed Syed

    2014-01-01

    The aim of the present work was to prepare and evaluate mucoadhesive microspheres of Lamivudine. Microspheres were formulated using sodium alginate (5%) with mucoadhesive polymer (Chitosan 1%) and copolymer Sodium CMC HPMC, Xanthan gum (XG) in concentration of 1% (Chitosan1% + HPMC1%) (1%) retarding agents and 10% of Calcium chloride (CaCl2), Aluminum sulphate (AlSO4) as cross linking agents by employing Ionic Gelation Technique. The particle size was characterized for by scanning electron mi...

  3. Transformation of oligoaniline microspheres to platelike nitrogen-containing carbon

    Czech Academy of Sciences Publication Activity Database

    Morávková, Zuzana; Trchová, Miroslava; Tomšík, Elena; Zhigunov, Alexander; Stejskal, Jaroslav

    2013-01-01

    Roč. 117, č. 5 (2013), s. 2289-2299 ISSN 1932-7447 R&D Projects: GA ČR GAP205/12/0911; GA ČR GPP108/11/P763 Institutional research plan: CEZ:AV0Z40500505 Institutional support: RVO:61389013 Keywords : anilin e * anilin e oligomers * polyaniline Subject RIV: CD - Macromolecular Chemistry Impact factor: 4.835, year: 2013

  4. Comparative activity of TiO{sub 2} microspheres and P25 powder for organic degradation: Implicative importance of structural defects and organic adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chuan [Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 401122 (China); Liu, Hong, E-mail: liuhong@cigit.ac.cn [Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 401122 (China); Liu, Yuan [Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 401122 (China); He, Guang’an [School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Jiang, Chengchun [School of Civil and Environmental Engineering, Shenzhen Polytechnic, Shenzhen 518055 (China)

    2014-11-15

    Highlights: • Adsorption of TiO{sub 2} microspheres was stronger than P25, while less active. • P25 was more active owing to its oxygen vacancy and Ti(III). • Difference in the adsorption abilities of TiO{sub 2} microspheres varied kinetic models. - Abstract: TiO{sub 2} microspheres have been employed as a promisingly new photocatalyst for water and wastewater treatment. P25 TiO{sub 2} is commonly employed and its properties are well established as photocatalyst. In this study, photocatalytic activities of the two TiO{sub 2} samples are compared by degrading sulfosalicylic acid (SSA), phenol, and 2,4-Dichlorophenoxyacetic acid (2,4-D) under 365 nm UV illumination in a suspension system at neutral pH and associated optimized TiO{sub 2} dosages. The results showed that the three organic compounds unexceptionally degraded more rapidly on P25 than on TiO{sub 2} microspheres in terms of the concentration–time curves and total organic carbon removals at 120 min. This might me attributed the presence of oxygen vacancies and Ti(III) defects already present on P25 as determined by electron paramagnetic resonance, implying that the defects played an important role for the enhancement of the charge transfer step as rate-determining step. The degradations of three organic compounds on P25 and TiO{sub 2} microspheres could be well described by the first-order rate equation, while the degradation kinetics of SSA on TiO{sub 2} microspheres was quite different. The difference was ascribed to the medium adsorption ability of SSA on the TiO{sub 2} surface.

  5. Formulation and characterization of catalase in albumin microspheres.

    Science.gov (United States)

    Siwale, Rodney C; Oettinger, Carl W; Pai, S Balakrishna; Addo, Richard; Uddin, Nasir; Siddig, Aladin; D'Souza, Martin J

    2009-08-01

    Catalase in albumin microspheres were formulated for intravenous administration to antagonize the effects of over-production of reactive oxygenated species (ROS) such as hydrogen peroxide (H(2)O(2)) in septic shock. The aim was to increase effective half-life of catalase and take advantage of the phagocytic uptake of the encapsulated catalase by the vascular endothelium. Catalase microspheres were prepared by spray-drying. The microspheres were evaluated for particle size, particle shape and surface morphology by scanning electron microscopy (SEM), drug encapsulation efficiency, chemical stability, thermal stability and in vitro drug release characteristics. The microspheres had a mean particle size of 4.7 +/- 2 microm, optimal for phagocytic uptake, as demonstrated by Makino et al. SEM revealed that microspheres were spherical with smooth surface morphology. An encapsulation efficiency of 91.5 +/- 3% was achieved and the encapsulated catalase was chemically and thermally stable. Application of in vitro drug release data to the Higuchi kinetic equation indicated matrix diffusion-controlled catalase release from albumin microspheres.

  6. Synthesis and characterization of Supeparamagnetics Microspheres (PMMA via suspension polymerization

    Directory of Open Access Journals (Sweden)

    Paulo Emilio Feuser

    2014-02-01

    Full Text Available Magnetics nanoparticles (NPMs has found many applications in biomedical and technological areas. The objective of this work is the preparation and characterization of PMMA microspheres containing NPMs coated with oleic acid (NPMs-AO. For the preparation of MNPs-AO was used the coprecipitation method in an aqueous medium. For the preparation of the superparamagnetic microspheres used in suspension polymerization technique. The microspheres showed a size distribution particles of approximately 150um and a spherical morphology. From the analysis of gel permeation chromatography (GPC determined the number average molecular weight (Mw of the magnetics microspheres and there was a variation in the Mw depending on the concentration of MNPs-AO in this reaction. To analyze the magnetic properties used the vibrating sample magnetometer (MAV. The microspheres showed superparamagnetic properties and a value of saturation magnetization (Ms of about 8 emu/g MNPs. Therefore you can conclude that it is possible to obtain superparamagnetics microspheres for a particular application, either, biomedical or technological.

  7. Innovative hydrogen storage in hollow glass-microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Keding, M.; Schmid, G.; Tajmar, M. [Austrian Research Centers, Vienna (Austria)

    2009-07-01

    Hydrogen storage technologies are becoming increasingly important for a number of future applications. The Austrian Research Centers (ARC) are developing a unique hydrogen storage system that combines the advantages of both hollow glass microsphere and chemical compound hydrogen storage, but eliminates their respective drawbacks. Water is utilized as a functional liquid to carry the hollow glass microspheres that are loaded with up to 700 bar of hydrogen gas. Sodium borohydride (NaBH{sub 4}) is then injected together with the glass microspheres into a reaction chamber where the water reacts catalytically with the NaBH{sub 4} producing hydrogen and heat. The heat is then utilized to release the hydrogen from the hollow glass microspheres providing a double hydrogen generation process without any external energy or heat during storage or gas release. The paper described this hydrogen storage system with particular reference to microspheres, the coating process, the experimental facility and NaBH{sub 4} test results. It was concluded that hydrogen storage and production on demand is possible with microspheres and sodium borohydride solution. 9 refs., 16 figs.

  8. Microfluidic Fabrication of Morphology-Controlled Polymeric Microspheres of Blends of Poly(4-butyltriphenylamine and Poly(methyl methacrylate

    Directory of Open Access Journals (Sweden)

    Saki Yoshida

    2018-04-01

    Full Text Available Multicomponent polymer particles with specific morphology are promising materials exhibiting novel functionality which cannot be obtained with single-component polymer particles. Particularly, the preparation of such kinds of polymer particles involving electrically or optically active conjugated polymers with uniform size is a challenging subject due to their intense demands. Here, microspheres of binary polymer blend consisting of poly(4-butyltriphenylamine (PBTPA/poly(methyl methacrylate (PMMA (1:1 in weight were produced via a microfluidic emulsification with a Y-shaped microreactor, and a subsequent solvent evaporation method. The flow rate of the dispersed phase (polymer solution was fixed to 7 µL/min, and 140 or 700 µL/min of the flow rate of the continuous phase (aqueous 0.6 wt % of poly(vinyl alcohol (PVA solution was utilized to produce the dispersion with different diameter. The concentration of dispersed phase was adjusted to 0.1 or 1.0 w/v%. Core-shell, Janus and dumbbell type microspheres were obtained dependent on the flow rate of continuous phase. Incomplete core-shell type microspheres were produced for the blend involving low molecular weight PMMA. Complex Janus and core-shell type microspheres were fabricated by the addition of sodium dodecyl sulfate (SDS to continuous phase. It is found that final morphologies are strongly dependent on the initial conditions of dispersion including the particle size suggesting that the morphologies are governed by the kinetical factors together with the conventionally accepted thermodynamic ones.

  9. Protein A and protein A/G coupled magnetic SiO2microspheres for affinity purification of immunoglobulin G.

    Science.gov (United States)

    Salimi, Kouroush; Usta, Duygu Deniz; Koçer, İlkay; Çelik, Eda; Tuncel, Ali

    2018-01-06

    Protein A carrying magnetic, monodisperse SiO 2 microspheres [Mag(SiO 2 )] with bimodal pore size distribution including both mesoporous and macroporous compartments were proposed as an affinity sorbent for IgG purification. Protein A was tightly bound onto the aldehyde functionalized-Mag(SiO 2 ) microspheres. The mesoporous compartment provided high surface area for protein A binding and IgG adsorption while the macropores made easier the intraparticular diffusion of protein A and IgG. The selection of relatively larger microspheres with high saturation magnetization allowed faster magnetic separation of affinity sorbent from the IgG isolation medium, less than 1min. With these properties, the proposed sorbent is an alternative to the common sorbents in the form of core-shell type, magnetic silica nanoparticles with more limited surface area and slower magnetic response. By using protein A attached-Mag(SiO 2 ) microspheres with the concentrations lower than 50mg/mL, IgG isolation from rabbit serum was performed with a purity higher than 95%, with an isolation yield comparable to commercial magnetic resins, and in shorter isolation periods. IgG could be also quantitatively isolated from rabbit serum with the sorbent concentrations higher than 50mg/mL. Successive IgG isolation runs indicated that no significant protein A leaching occurred from the magnetic matrix. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. WE-G-BRA-09: Microsphere Brachytherapy Failure Mode and Effects Analysis in a Dual-Vendor Environment

    Energy Technology Data Exchange (ETDEWEB)

    Younge, K C; Lee, C I; Feng, M; Novelli, P; Moran, J M; Prisciandaro, J I [Univ Michigan Medical Center, Ann Arbor, MI (United States)

    2015-06-15

    Purpose: To improve the safety and quality of a dual-vendor microsphere brachytherapy program with failure mode and effects analysis (FMEA). Methods: A multidisciplinary team including physicists, dosimetrists, a radiation oncologist, an interventional radiologist, and radiation safety personnel performed an FMEA for our dual-vendor microsphere brachytherapy program employing SIR-Spheres (Sirtex Medical Limited, Australia) and Theraspheres (BTG, England). We developed a program process tree and step-by-step instructions which were used to generate a comprehensive list of failure modes. These modes were then ranked according to severity, occurrence rate, and detectability. Risk priority numbers (RPNs) were calculated by multiplying these three scores together. Three different severity scales were created: one each for harmful effects to the patient, staff, or the institution. Each failure mode was ranked on one or more of these scales. Results: The group identified 164 failure modes for the microsphere program. 113 of these were ranked using the patient severity scale, 52 using the staff severity scale, and 50 using the institution severity scale. The highest ranked items on the patient severity scale were an error in the automated dosimetry worksheet (RPN = 297.5), and the incorrect target specified on the planning study (RPN = 135). Some failure modes ranked differently between vendors, especially those corresponding to dose vial preparation because of the different methods used. Based on our findings, we made several improvements to our QA program, including documentation to easily identify which product is being used, an additional hand calculation during planning, and reorganization of QA steps before treatment delivery. We will continue to periodically review and revise the FMEA. Conclusion: We have applied FMEA to our dual-vendor microsphere brachytherapy program to identify potential key weaknesses in the treatment chain. Our FMEA results were used to

  11. WE-G-BRA-09: Microsphere Brachytherapy Failure Mode and Effects Analysis in a Dual-Vendor Environment

    International Nuclear Information System (INIS)

    Younge, K C; Lee, C I; Feng, M; Novelli, P; Moran, J M; Prisciandaro, J I

    2015-01-01

    Purpose: To improve the safety and quality of a dual-vendor microsphere brachytherapy program with failure mode and effects analysis (FMEA). Methods: A multidisciplinary team including physicists, dosimetrists, a radiation oncologist, an interventional radiologist, and radiation safety personnel performed an FMEA for our dual-vendor microsphere brachytherapy program employing SIR-Spheres (Sirtex Medical Limited, Australia) and Theraspheres (BTG, England). We developed a program process tree and step-by-step instructions which were used to generate a comprehensive list of failure modes. These modes were then ranked according to severity, occurrence rate, and detectability. Risk priority numbers (RPNs) were calculated by multiplying these three scores together. Three different severity scales were created: one each for harmful effects to the patient, staff, or the institution. Each failure mode was ranked on one or more of these scales. Results: The group identified 164 failure modes for the microsphere program. 113 of these were ranked using the patient severity scale, 52 using the staff severity scale, and 50 using the institution severity scale. The highest ranked items on the patient severity scale were an error in the automated dosimetry worksheet (RPN = 297.5), and the incorrect target specified on the planning study (RPN = 135). Some failure modes ranked differently between vendors, especially those corresponding to dose vial preparation because of the different methods used. Based on our findings, we made several improvements to our QA program, including documentation to easily identify which product is being used, an additional hand calculation during planning, and reorganization of QA steps before treatment delivery. We will continue to periodically review and revise the FMEA. Conclusion: We have applied FMEA to our dual-vendor microsphere brachytherapy program to identify potential key weaknesses in the treatment chain. Our FMEA results were used to

  12. Demagnetization treatment of remanent composite microspheres studied by alternating current susceptibility measurements

    NARCIS (Netherlands)

    van Berkum, S.; Erné, B.H.

    2013-01-01

    The magnetic remanence of silica microspheres with a low concentration of embedded cobalt ferrite nanoparticles is studied after demagnetization and remagnetization treatments. When the microspheres are dispersed in a liquid, alternating current (AC) magnetic susceptibility spectra reveal a constant

  13. Protein microspheres for controlled drug delivery and related analysis of biopolymers

    Science.gov (United States)

    Kirk, James Forrest

    Rheumatoid arthritis (RA) is a systemic disorder which manifests itself most notably in the synovial joints. In recent years, methotrexate (MTX), a foliate antagonist, has been used with some success for treatment of RA. MTX has a maximum cumulative dose beyond which it becomes dangerous to administer due primarily to liver toxicity. This unfortunate side effect has prompted research into means of delivering MTX to the synovial joint in hopes of making more efficient use of the drug. Both MTX and its sodium salt (Na-MTX) were loaded into microspheres (MS) composed of bovine serum albumin (BSA) stabilized by cross linking with dialdehydes or ferric ion. MS were prepared with two levels of drug loading at two different levels of cross linking. MTX loading densities as high as 46.8% w/w were achieved in the aldehyde cross linking system and as high as 46.3% w/w were achieved with ferric ion cross linking. Using Na-MTX, the values were 37.2% w/w and 31.7% w/w respectively. Both MTX and Na-MTX were elutable from the MS into phosphate buffered saline at 37sp°C. MTX elution from aldehyde cross linked microspheres was load dependent with ca. 60% eluted by 9 hours at low loading and ca. 60% eluted by 24 hours at high loading. In the ferric ion cross link system, the elution was independent of loading with 50% elution occurring between 20 and 48 hours. Na-MTX elution was independent of drug loading or cross link system with 50% elution occurring in less than two hours in all cases. Other investigations included the loading of mitoxantrone (NOV) and of enzyme. NOV was loaded onto BSA microspheres to a concentration of 19.3% w/w and was used successfully in the treatment of murine ovarian tumors. Acid phosphatase was successfully loaded onto and into BSA microspheres. This enzyme retained its initial activity up to four months on post-loaded spheres. The enzyme also remained active inside the microsphere as demonstrated by a substrate cleavage assay.

  14. Preparation and Comparative Characterization of Alginate-Made Microcapsules and Microspheres Containing Tomato, Seabuckthorn Juices and Pumpkin Oil

    Directory of Open Access Journals (Sweden)

    Florina Csernatoni

    2015-05-01

    Full Text Available Recent studies have shown the benefits of tomatoes, seabuckthorn juices and pumpkin oil, rich in bioactives with antioxidant capacity, in the prevention of prostate diseases. To stabilize their antioxidant activity, microencapsulation represent a good technological alternative, improving the stability and bioavailability of bioactive molecules ( phenolic derivatives, carotenoids, phytosterols, vitamins.   The aim of the study was to prepare and characterize microspheres and microcapsules based on emulsions made of natural polymers like Natrium alginate mixed with tomato and/or seabuckthorn juices, with or without pumpkin oil.  The viscosity of emulsions, the morphology of microcapsules and microspheres were characterized comparatively and the bioactives were monitored by UV-Vis spectrometry.  In the lipophilic extract there were identified, before and after encapsulation, different classes of compounds, from lipids, to phenolic acid derivatives, flavonoids and carotenoids. Carotenoids were the major components having concentrations from 9.16 up to 19.71 mg/100 g sample. The viscosity of  each emulsion including juices, oil and natrium alginate 2%, before encapsulation, showed differences, dependent on the oil addition and speed of homogenization. The macroscopic and microscopic structure of microspheres and microcapsules were comparatively evaluated. Both microspheres and microcapsules had external diameters  ranging from 750 to 900 μm and the microcapsules’ oily core of 150-180 μm. The results obtained from emulsion’s viscosity will be correlated with the rigidity and optimal release rate of bioactive molecules from microcapsules and microspheres.  Further studies are directed towards these aspects.

  15. Hydrophilic Nb{sup 5+}-immobilized magnetic core–shell microsphere – A novel immobilized metal ion affinity chromatography material for highly selective enrichment of phosphopeptides

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xueni; Liu, Xiaodan; Feng, Jianan [Pharmaceutical Analysis Department, School of Pharmacy, Fudan University, Shanghai 201203 (China); Li, Yan, E-mail: yanli@fudan.edu.cn [Pharmaceutical Analysis Department, School of Pharmacy, Fudan University, Shanghai 201203 (China); Deng, Chunhui [Department of Chemistry and Institutes of Biomedical Sciences, Fudan University, Shanghai 200433 (China); Duan, Gengli [Pharmaceutical Analysis Department, School of Pharmacy, Fudan University, Shanghai 201203 (China)

    2015-06-23

    Highlights: • A new IMAC material (Fe{sub 3}O{sub 4}@PD-Nb{sup 5+}) was synthesized. • The strong magnetic behaviors of the microspheres ensure fast and easy separation. • The enrichment ability was tested by human serum and nonfat milk. • The results were compared with other IMAC materials including the commercial kits. • All results proved the good enrichment ability, especially for multiphosphopeptides. - Abstract: Rapid and selective enrichment of phosphopeptides from complex biological samples is essential and challenging in phosphorylated proteomics. In this work, for the first time, niobium ions were directly immobilized on the surface of polydopamine-coated magnetic microspheres through a facile and effective synthetic route. The Fe{sub 3}O{sub 4}@polydopamine-Nb{sup 5+} (denoted as Fe{sub 3}O{sub 4}@PD-Nb{sup 5+}) microspheres possess merits of high hydrophilicity and good biological compatibility, and demonstrated low limit of detection (2 fmol). The selectivity was also basically satisfactory (β-casein:BSA = 1:500) to capture phosphopeptides. They were also successfully applied for enrichment of phosphopeptides from real biological samples such as human serum and nonfat milk. Compared with Fe{sub 3}O{sub 4}@PD-Ti{sup 4+} microspheres, the Fe{sub 3}O{sub 4}@PD-Nb{sup 5+} microspheres exhibit superior selectivity to multi-phosphorylated peptides, and thus may be complementary to the conventional IMAC materials.

  16. Preparation of Nano-TiO₂-Coated SiO₂ Microsphere Composite Material and Evaluation of Its Self-Cleaning Property.

    Science.gov (United States)

    Sun, Sijia; Deng, Tongrong; Ding, Hao; Chen, Ying; Chen, Wanting

    2017-11-03

    In order to improve the dispersion of nano-TiO₂ particles and enhance its self-cleaning properties, including photocatalytic degradation of pollutants and surface hydrophilicity, we prepared nano-TiO₂-coated SiO₂ microsphere composite self-cleaning materials (SiO₂-TiO₂) by co-grinding SiO₂ microspheres and TiO₂ soliquid and calcining the ground product. The structure, morphology, and self-cleaning properties of the SiO₂-TiO₂ were characterized. The characterization results showed that the degradation efficiency of methyl orange by SiO₂-TiO₂ was 97%, which was significantly higher than that obtained by pure nano-TiO₂. The minimum water contact angle of SiO₂-TiO₂ was 8°, indicating strong hydrophilicity and the good self-cleaning effect. The as-prepared SiO₂-TiO₂ was characterized by the nano-TiO₂ particles uniformly coated on the SiO₂ microspheres and distributed in the gap among the microspheres. The nano-TiO₂ particles were in an anatase phase with the particle size of 15-20 nm. The nano-TiO₂ particles were combined with SiO₂ microspheres via the dehydroxylation of hydroxyl groups on their surfaces.

  17. Microsphere-based super-resolution scanning optical microscope.

    Science.gov (United States)

    Huszka, Gergely; Yang, Hui; Gijs, Martin A M

    2017-06-26

    High-refractive index dielectric microspheres positioned within the field of view of a microscope objective in a dielectric medium can focus the light into a so-called photonic nanojet. A sample placed in such nanojet can be imaged by the objective with super-resolution, i.e. with a resolution beyond the classical diffraction limit. However, when imaging nanostructures on a substrate, the propagation distance of a light wave in the dielectric medium in between the substrate and the microsphere must be small enough to reveal the sample's nanometric features. Therefore, only the central part of an image obtained through a microsphere shows super-resolution details, which are typically ∼100 nm using white light (peak at λ = 600 nm). We have performed finite element simulations of the role of this critical distance in the super-resolution effect. Super-resolution imaging of a sample placed beneath the microsphere is only possible within a very restricted central area of ∼10 μm 2 , where the separation distance between the substrate and the microsphere surface is very small (∼1 μm). To generate super-resolution images over larger areas of the sample, we have fixed a microsphere on a frame attached to the microscope objective, which is automatically scanned over the sample in a step-by-step fashion. This generates a set of image tiles, which are subsequently stitched into a single super-resolution image (with resolution of λ/4-λ/5) of a sample area of up to ∼10 4 μm 2 . Scanning a standard optical microscope objective with microsphere therefore enables super-resolution microscopy over the complete field-of-view of the objective.

  18. Fabrication of Polymer Microspheres for Optical Resonator and Laser Applications.

    Science.gov (United States)

    Yamamoto, Yohei; Okada, Daichi; Kushida, Soh; Ngara, Zakarias Seba; Oki, Osamu

    2017-06-02

    This paper describes three methods of preparing fluorescent microspheres comprising π-conjugated or non-conjugated polymers: vapor diffusion, interface precipitation, and mini-emulsion. In all methods, well-defined, micrometer-sized spheres are obtained from a self-assembling process in solution. The vapor diffusion method can result in spheres with the highest sphericity and surface smoothness, yet the types of the polymers able to form these spheres are limited. On the other hand, in the mini-emulsion method, microspheres can be made from various types of polymers, even from highly crystalline polymers with coplanar, π-conjugated backbones. The photoluminescent (PL) properties from single isolated microspheres are unusual: the PL is confined inside the spheres, propagates at the circumference of the spheres via the total internal reflection at the polymer/air interface, and self-interferes to show sharp and periodic resonant PL lines. These resonating modes are so-called "whispering gallery modes" (WGMs). This work demonstrates how to measure WGM PL from single isolated spheres using the micro-photoluminescence (µ-PL) technique. In this technique, a focused laser beam irradiates a single microsphere, and the luminescence is detected by a spectrometer. A micromanipulation technique is then used to connect the microspheres one by one and to demonstrate the intersphere PL propagation and color conversion from coupled microspheres upon excitation at the perimeter of one sphere and detection of PL from the other microsphere. These techniques, µ-PL and micromanipulation, are useful for experiments on micro-optic application using polymer materials.

  19. EFFECTS OF THE GRAM STAIN ON MICROSPHERES FROM THERMAL POLYAMINO ACIDS1

    Science.gov (United States)

    Fox, Sidney W.; Yuyama, Shuhei

    1963-01-01

    Fox, Sidney W. (The Florida State University, Tallahassee) and Shuhei Yuyama. Effects of the Gram stain on microspheres from thermal polyamino acids. J. Bacteriol. 85:279–283. 1963.—Microspheres produced from acid proteinoid accept the Gram stain. The stain is negative, but microspheres produced from mixtures containing a sufficient proportion of lysine proteinoid stain positive. Microspheres produced from mixtures containing the appropriate proportions contain individuals which stain positive and others which stain negative. Images PMID:13959050

  20. Preparation of open porous polycaprolactone microspheres and their applications as effective cell carriers in hydrogel system

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Qingchun [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering (China); Tan, Ke; Ye, Zhaoyang [State Key Laboratory of Bioreactor Engineering, School of Bioengineering, East China University of Science and Technology, Shanghai, 200237 China (China); Zhang, Yan, E-mail: zhang_yan@ecust.edu.cn [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering (China); Tan, Wensong [State Key Laboratory of Bioreactor Engineering, School of Bioengineering, East China University of Science and Technology, Shanghai, 200237 China (China); Lang, Meidong, E-mail: mdlang@ecust.edu.cn [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering (China)

    2012-12-01

    Common hydrogel, composed of synthetic polymers or natural polysaccharides could not support the adhesion of anchorage-dependent cells due to the lack of cell affinitive interface and high cell constraint. The use of porous polyester microspheres as cell-carriers and introduction of cell-loaded microspheres into the hydrogel system might overcome the problem. However, the preparation of the open porous microsphere especially using polycaprolactone (PCL) has been rarely reported. Here, the open porous PCL microspheres were fabricated via the combined emulsion/solvent evaporation and particle leaching method. The microspheres exhibited porous surface and inter-connective pore structure. Additionally, the pore structure could be easily controlled by adjusting the processing parameters. The surface pore size could be altered from 20 {mu}m to 80 {mu}m and the internal porosities were varied from 30% to 70%. The obtained microspheres were evaluated to delivery mesenchymal stem cells (MSCs) and showed the improved cell adhesion and growth when compared with the non-porous microspheres. Then, the MSCs loaded microspheres were introduced into agarose hydrogel. MSCs remained alive and sustained proliferation in microsphere/agarose composite in 5-day incubation while a decrement of MSCs viabilities was found in agarose hydrogel without microspheres. The results indicated that the microsphere/hydrogel composite had a great potential in cell therapy and injectable system for tissue regeneration. Highlights: Black-Right-Pointing-Pointer The open porous polycaprolactone microspheres were fabricated using paraffin as a porogen. Black-Right-Pointing-Pointer The microspheres exhibited porous surface and inter-connective pore structure. Black-Right-Pointing-Pointer The surface and internal pore size and porosity of microsphere could be controlled. Black-Right-Pointing-Pointer The porous microspheres exhibited an improved cell adhesion and proliferation. Black

  1. Investigations on vinylene carbonate. VI: Immobilization of alkaline phosphatase onto poly(vinylene carbonate) - jeffamine hydrogel beads

    NARCIS (Netherlands)

    Chen, G.H.; Chen, Guohua; van der Does, L.; Bantjes, A.; Bantjes, Adriaan

    1993-01-01

    Hydrogel-like polymers with reactive cyclic carbonate (CCA) groups have been obtained by the cross-linking reaction of poly(vinylene carbonate) (PVCA) with Jeffamines®. By this reaction, microspheric hydrogel beads with a high water content and a high concentration of reactive CCA groups were

  2. Determination of sulfur forms in wine including free and total sulfur dioxide based on molecular absorption of carbon monosulfide in the air-acetylene flame.

    Science.gov (United States)

    Huang, Mao Dong; Becker-Ross, Helmut; Florek, Stefan; Heitmann, Uwe; Okruss, Michael; Patz, Claus-Dieter

    2008-01-01

    A new method for the determination of sulfur forms in wine, i.e., free SO(2), total SO(2), bound SO(2), total S, and sulfate, is presented. The method is based on the measurement of the carbon monosulfide (CS) molecular absorption produced in a conventional air-acetylene flame using high-resolution continuum source absorption spectrometry. Individual sulfur forms can be distinguished because of the different sensitivities of the corresponding CS molecular absorption. The sensitivity of free SO(2) is about three times higher than the value for bound SO(2) and sulfate. The method makes use of procedures similar to those used in classic reference methods. Its performance is verified by analyzing six wine samples. Relative standard deviations are between 5 and 13% for free SO(2) and between 1 and 3% for total SO(2). For the validation of the accuracy of the new method, the results are compared with those of reference methods. The agreement of the values for total SO(2) with values of the classic method is satisfactory: five out of six samples show deviations less than 16%. Due to the instability of free SO(2) in wine and the known problems of the used reference method, serious deviations of the free SO(2) results are found for three samples. The evaluation of the limits of detection focuses on the value for free SO(2), which is the sulfur form having by far the lowest concentration in wine. Here, the achievable limit of detection is 1.8 mg L(-1). [figure: see text] Detection of non-metal elements using continuum source flame absorption spectrometry.

  3. Optically Reconfigurable Chiral Microspheres of Self-Organized Helical Superstructures with Handedness Inversion.

    Science.gov (United States)

    Wang, Ling; Chen, Dong; Gutierrez-Cuevas, Karla G; Bisoyi, Hari Krishna; Fan, Jing; Zola, Rafael S; Li, Guoqiang; Urbas, Augustine M; Bunning, Timothy J; Weitz, David A; Li, Quan

    2017-01-01

    Optically reconfigurable monodisperse chiral microspheres of self-organized helical superstructures with dynamic chirality were fabricated via a capillary-based microfluidic technique. Light-driven handedness-invertible transformations between different configurations of microspheres were vividly observed and optically tunable RGB photonic cross-communications among the microspheres were demonstrated.

  4. Factors influencing the deposition of hydroxyapatite coating onto hollow glass microspheres

    International Nuclear Information System (INIS)

    Jiao, Yan; Xiao, Gui-Yong; Xu, Wen-Hua; Zhu, Rui-Fu; Lu, Yu-Peng

    2013-01-01

    Hydroxyapatite (HA) and HA coated microcarriers for cell culture and delivery have attracted more attention recently, owing to the rapid progress in the field of tissue engineering. In this research, a dense and uniform HA coating with the thickness of about 2 μm was successfully deposited on hollow glass microspheres (HGM) by biomimetic process. The influences of SBF concentration, immersion time, solid/liquid ratio and activation of HGM on the deposition rate and coating characteristics were discussed. X-ray diffraction (XRD) and Fourier transform infrared spectrum (FTIR) analyses revealed that the deposited HA is poorly crystalline. The thickness of HA coating showed almost no increase after immersion in 1.5SBF for more than 15 days with the solid/liquid ratio of 1:150. At the same time, SBF concentration, solid/liquid ratio and activation treatment played vital roles in the formation of HA coating on HGM. This poorly crystallized HA coated HGM could have potential use as microcarrier for cell culture. Highlights: • HA coatings were deposited on hollow glass microspheres by biomimetic process. • The obtained HA coating was poorly crystalline and carbonated. • The influencing factors of deposition rate and coating characteristics were studied. • The thickness of HA coating showed almost no increase after immersion for 15 days

  5. Preparation of chitosan-TPP microspheres as resveratrol carriers.

    Science.gov (United States)

    Cho, Ah Ra; Chun, Yong Gi; Kim, Bum Keun; Park, Dong June

    2014-04-01

    Resveratrol (3,4',5-trihydroxy-trans-stilbene)-loaded chitosan-sodium tripolyphosphate (TPP) microspheres using high (310 to 375 kDa) and medium (190 to 310 kDa) molecular weight chitosan and TPP in varying concentrations were produced to improve resveratrol bioavailability. A 450 μm nozzle encapsulator was used to produce the microspheres. The mean microsphere particle size was between 160 and 206 μm, and exhibited a narrower size distribution as the TPP solution concentration increased. The encapsulation efficiency increased from 94% to 99% with a decrease in chitosan concentration from 1% to 0.5% and a decrease in crystallinity of the microspheres. FTIR data showed a polyelectrolyte interaction between chitosan and TPP. X-ray diffraction patterns were matched up with DSC and FTIR, which shows decrease of crystallinity and enhancement of hydrogen bonding with TPP concentration. An increase in the concentration of TPP solution from 1% to 3% led to a lower initial burst of resveratrol release. These results suggest that chitosan-TPP microspheres could be used as a potential delivery system to control the release of resveratrol. © 2014 Institute of Food Technologists®

  6. Pharmacodynamics of diclofenac from novel Eudragit entrapped microspheres.

    Science.gov (United States)

    Momoh, M A; Kenechukwu, F C; Adedokun, M O; Odo, C E; Attama, A A

    2014-05-01

    Effective clinical utilization of non-steroidal anti-inflammatory drugs such as diclofenac sodium (DS) is significantly limited by their ulcerogenic potential and poor bioavailability after oral administration, thus necessitating the need for a better carrier to minimize these obvious limitations. The objective of this study was to evaluate Eudragit® RS100/RL100 microspheres formulated by the solvent-evaporation technique for improved delivery of diclofenac. Three batches of (DF1, DF2 and DF3) microspheres were prepared using different ratios of Eudragit RS-100 and RL-100 polymers based on the solvent-evaporation method. The microspheres were characterized based on morphological properties, particle size analysis and encapsulation efficiency (EE%). In vitro release of DS was investigated in both 0.1 N HCl (pH 1.2) and phosphate-buffered saline (pH 7.4), while anti-inflammatory studies were evaluated in the rat model. Maximum EE% of 86.61 ± 0.11, 88.14 ± 0.16 and 85.50 ± 0.21 was obtained for DF1, DF2 and DF3, respectively. Discrete, smooth and brownish microspheres of size range 437 ± 0.01-479 ± 0.21 µm were obtained. Release of DS from the formulation depends on the polymer ratio. All the batches exhibited good anti-inflammatory activities. Microsphere formulations based on Eudragit® polymers would likely offer a reliable and alternative means of delivering DS orally.

  7. Magnetic propulsion of microspheres at liquid-glass interfaces

    Science.gov (United States)

    Helgesen, Geir

    2018-02-01

    Bio-coated, magnetic microspheres have many applications in biotechnology and medical technology as a tool to separate and extract cells or molecules in a water solution by applying external strong magnetic field gradients. However, magnetic microspheres with or without attached cargo can also be separated in the liquid solution if they are exposed to alternating or rotating, relatively weak magnetic fields. Microspheres that have a higher density than the liquid will approach the bottom surface of the sample cell, and then a combination of viscous and surface frictional forces can propel the magnetic microspheres along the surface in a direction perpendicular to the axis of field rotation. Experiments demonstrating this type of magnetic propulsion are shown, and the forces active in the process are discussed. The motion of particles inside sample cells that were tilted relative to the horizontal direction was studied, and the variation of propulsion velocity as a function of tilt angle was used to find the values of different viscous and mechanical parameters of motion. Propulsion speeds of up to 5 μm/s were observed and were found to be caused by a partly rolling and partly slipping motion of rotating microspheres with a slipping coefficient near 0.6.

  8. A review on target drug delivery: magnetic microspheres

    Directory of Open Access Journals (Sweden)

    Amit Chandna

    2013-01-01

    Magnetic microsphere is newer approach in pharmaceutical field. Magnetic microspheres as an alternative to traditional radiation methods which use highly penetrating radiation that is absorbed throughout the body. Its use is limited by toxicity and side effects. The aim of the specific targeting is to enhance the efficiency of drug delivery & at the same time to reduce the toxicity & side effects. This kind of delivery system is very much important which localises the drug to the disease site. In this larger amount of freely circulating drug can be replaced by smaller amount of magnetically targeted drug. Magnetic carriers receive magnetic responses to a magnetic field from incorporated materials that are used for magnetic microspheres are chitosan, dextran etc. magnetic microspheres can be prepared from a variety of carrier material. One of the most utilized is serum albumin from human or other appropriate species. Drug release from albumin microspheres can be sustained or controlled by various stabilization procedures generally involving heat or chemical cross-linking of the protein carrier matrix.

  9. Solvent/Non-Solvent Sintering To Make Microsphere Scaffolds

    Science.gov (United States)

    Laurencin, Cato T.; Brown, Justin L.; Nair, Lakshmi

    2011-01-01

    A solvent/non-solvent sintering technique has been devised for joining polymeric microspheres to make porous matrices for use as drug-delivery devices or scaffolds that could be seeded with cells for growing tissues. Unlike traditional sintering at elevated temperature and pressure, this technique is practiced at room temperature and pressure and, therefore, does not cause thermal degradation of any drug, protein, or other biochemical with which the microspheres might be loaded to impart properties desired in a specific application. Also, properties of scaffolds made by this technique are more reproducible than are properties of comparable scaffolds made by traditional sintering. The technique involves the use of two miscible organic liquids: one that is and one that is not a solvent for the affected polymer. The polymeric microspheres are placed in a mold having the size and shape of the desired scaffold, then the solvent/non-solvent mixture is poured into the mold to fill the void volume between the microspheres, then the liquid mixture is allowed to evaporate. Some of the properties of the resulting scaffold can be tailored through choice of the proportions of the liquids and the diameter of the microspheres.

  10. Functionalized sio2 microspheres for extracting oil from produced water

    KAUST Repository

    Mishra, Himanshu

    2017-03-16

    Functionalized material, methods of producing the functionalized material, and use thereof for separation processes such as but not limited to use for separating and extracting a dissolved organic foulant, charged contaminant or oily matter or any combination thereof from water, such as produced water, are provided. In an embodiment, the functionalized material is a mineral material, such as mica, silica (e.g. an SiO2 microsphere) or a metal oxide, and the outer surface of the material is functionalized with an alkyl chain or a perfluorinated species. In an embodiment, the method of making the functionalized material, includes: a) providing a mineral material; b) providing an alkyl chain and/or a perfluorinated species, the alkyl chain or perfluorinated species selected to dissolve organic foulants, charged contaminants or oily matter from water or any combination thereof; c) hydroxylating the material via a concentrated acid solution or a basic solution; and d) grafting the alkyl chain and/or the perfluorinated species onto the material via a silanation reaction.

  11. Temperature influence in crystallinity of polymer microspheres; Influencia da temperatura na cristalinidade de microesferas polimericas

    Energy Technology Data Exchange (ETDEWEB)

    Rezende, Cristiane de P.; Novack, Katia M., E-mail: knovack@iceb.ufop.br [Universidade Federal de Ouro Preto - UFOP, ICEB, DEQUI, Ouro Preto, MG (Brazil)

    2011-07-01

    Drug delivery technology is evolving through the creation of new techniques of drug delivery effectively. The new methods used in drugs administration are based in microencapsulation process. Microsphere encapsulation modifies drug delivery bringing benefits and efficiency. In this work has been evaluated the influence of temperature in microspheres preparation. Microspheres were obtained by PMMA-co-PEG (COP) copolymer with indomethacin inserted in polymer matrix. Samples were characterized by SEM, DSC and XRD. SEM micrographs confirmed the formation of different sizes of microspheres and it was verified that higher temperatures make more crystalline microspheres. (author)

  12. Biloma Following Transcatheter Arterial Chemoembolization with Microspheres: A Case Report

    Directory of Open Access Journals (Sweden)

    Chao-Kuan Huang

    2007-09-01

    Full Text Available We report a case of inrrahepatic biloma following transcatheter arterial chemoembolization (TACE with microspheres in a 44-year-old male patient. He was diagnosed with hepatocellular carcinoma with satellite nodules and inrrahepatic duct invasion in August 2004. TACE was performed with a mixture of lipiodol, epirubicin hydrochloride, and mitomycin followed by microspheres as devas-cularizing material. Local external irradiation was performed on the area of intrahepatic duct invasion after the first TACE. Owing to local rumor progression and growth of new rumor nodules, a series of TACEs were performed. However, fever and diarrhea developed 2 weeks after the third TACE. Biloma with infection was diagnosed and was then treated successfully with percutaneous drainage and antibiotics. Embolization using microspheres at the proximal right hepatic artery was considered to have been the jeopardizing etiologic factor of biloma formation.

  13. Electrodepositing of Au on hollow PS micro-spheres

    International Nuclear Information System (INIS)

    Sun Jingyuan; Zhang Yunwang; Du Kai; Wan Xiaobo; Xiao Jiang; Zhang Wei; Zhang Lin; Chen Jing

    2010-01-01

    Using the self-regulating new micro-sphere electrodepositing device, the techniques of electrodepositing gold on hollow PS micro-spheres were established. The experiment was carried out under the following conditions: voltage was about 0.7 ∼ 0.8 V, current density was 2.0 mA · cm -2 , the temperature was 45 degree C, cathode rotating rate was 250 r · min -1 , flow rate of the solution was 7 mL · min -1 · cm -2 . Hollow gold-plated micro-spheres were prepared with well spherical symmetry, uniform thickness and surface smoothness under 500 nm. The speed of the gold depositing was 6 μm · h -1 . (authors)

  14. Nano pores evolution in hydroxyapatite microsphere during spark plasma sintering

    Directory of Open Access Journals (Sweden)

    Lin C.

    2011-01-01

    Full Text Available Micron-spherical granules of hydroxyapatite (HAp nanoparticles were prepared by powder granulation methods. Through subsequent sintering, porous HAp microspheres with tailored pore and grain framework structures were obtained. Detailed microstructure investigation by SEM and TEM revealed the correlation of the pore structure and the necking strength with the sintering profiles that determine the coalescence features of the nanoparticles. The partially sintered porous HAp microspheres containing more than 50% porosity consisting of pores and grains both in nano-scale are active in inducing the precipitation of HAp in simulated body fluid. The nano-porous HAp microspheres with an extensive surface and interconnecting pores thus demonstrate the potential of stimulating the formation of collagen and bone and the integration with the newly formed bones during physiological bone remodeling.

  15. Nuclear fuel element with axially aligned fuel pellets and fuel microspheres therein

    Science.gov (United States)

    Sease, J.D.; Harrington, F.E.

    1973-12-11

    Elongated single- and multi-region fuel elements are prepared by replacing within a cladding container a coarse fraction of fuel material which includes plutonium and uranium in the appropriate regions of the fuel element and then infiltrating with vibration a fine-sized fraction of uranium-containing microspheres throughout all interstices in the coarse material in a single loading. The fine, rigid material defines a thin annular layer between the coarse fraction and the cladding to reduce adverse mechanical and chemical interactions. (Official Gazette)

  16. Treatment of diffuse large B-cell lymphoma of the liver with yttrium-90 microsphere embolization.

    Science.gov (United States)

    Fenske, Timothy S; Benjamin, Heather; Kroft, Steven H; Hohenwalter, Eric J; Rilling, William S

    2008-11-01

    A 41-year-old male with a 4-year history of chronic hepatitis C presented with a 1-month history of abdominal pain, fatigue, weight loss, and night sweats. Laboratory examinations, chest, abdomen, and pelvic CT scans, PET-CT scans, ultrasound-guided needle biopsies of liver lesions, bone-marrow biopsy, flow cytometry, and immunohistochemical staining for B-cell markers including CD20. Chemoresistant diffuse large B-cell lymphoma, with gradual loss of CD20 antigen expression. Embolization of hepatic tumors using yttrium-90 microspheres (Therasphere, Theragenics Corporation, Buford, GA).

  17. Liver abscess following radioembolization with yttrium-90 microspheres.

    Science.gov (United States)

    Korkmaz, Mehmet; Bozkaya, Halil; Çınar, Celal; Şanal, Bekir; Güneyli, Serkan; Parıldar, Mustafa; Oran, İsmail

    2014-12-01

    Radioembolization with yttrium-90 microspheres is an accepted and useful intervention model with minimal invasion in both primary and secondary liver malignancies. Radioembolization may lead to some complications. Liver abscess is a rare complication that can occur several weeks after radioembolization treatment of liver tumor with yttrium-90 microspheres. There are only a few case reports on hepatic liver abscess observed in early term of radioembolization treatment, and our case also constitutes a rare report that may contribute to the possible future improvements in radioembolization field to get more insight into the current understanding of the formation of some deleterious insults such as hepatic abscess.

  18. UO2 microspheres obtainment through the internal gelation methods

    International Nuclear Information System (INIS)

    Sterba, M.E.; Gomez Constenla, A.

    1987-01-01

    UO 2 microspheres obtainment process through the internal gelation method which allows the spheres' obtainment of uniform size is detailed herein, varying the same among 0.3 and 1.7 mm of diameter. The sintered density reaches 10.78 g/cm 3 , permitting the fuels fabrication dispersed and vibro-compacted fuels. The trichloroethylene use implementation as gelation agent is described, thus reducing the number of stages in the microspheres fabrication. At the same time, the uranium sun composition has been modified so as to be compatible with the use solvent. (Author)

  19. Fast Adsorption of Soft Hydrogel Microspheres on Solid Surfaces in Aqueous Solution.

    Science.gov (United States)

    Matsui, Shusuke; Kureha, Takuma; Hiroshige, Seina; Shibata, Mikihiro; Uchihashi, Takayuki; Suzuki, Daisuke

    2017-09-25

    The real-time adsorption behavior of polymeric colloidal microspheres onto solid surfaces in aqueous solution was visualized for the first time using high-speed atomic force microscopy (HS-AFM) to reveal how the softness of the microspheres affects their dynamic adsorption. Studies that focus on the deformability of microspheres upon dynamic adsorption have not yet been reported, most likely on account of a lack of techniques that appropriately depict the dynamic adsorption and deformation behavior of individual microspheres at the nanoscale in real time. In this study, the deformability of microspheres plays a crucial role on the adsorption kinetics, that is, soft hydrogel microspheres adsorb faster than harder elastomeric or rigid microspheres. These results should provide insight towards development of new colloidal nanomaterials that exhibit effective adsorption on specific sites in aqueous solution. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Biomass Vanillin-Derived Polymeric Microspheres Containing Functional Aldehyde Groups: Preparation, Characterization, and Application as Adsorbent.

    Science.gov (United States)

    Zhang, Huanyu; Yong, Xueyong; Zhou, Jinyong; Deng, Jianping; Wu, Youping

    2016-02-03

    The contribution reports the first polymeric microspheres derived from a biomass, vanillin. It reacted with methacryloyl chloride, providing monomer vanillin methacrylate (VMA), which underwent suspension polymerization in aqueous media and yielded microspheres in high yield (>90 wt %). By controlling the N2 bubbling mode and by optimizing the cosolvent for dissolving the solid monomer, the microspheres were endowed with surface pores, demonstrated by SEM images and mercury intrusion porosimetry measurement. Taking advantage of the reactive aldehyde groups, the microspheres further reacted with glycine, thereby leading to a novel type of Schiff-base chelating material. The functionalized microspheres demonstrated remarkable adsorption toward Cu(2+) (maximum, 135 mg/g) which was taken as representative for metal ions. The present study provides an unprecedented class of biobased polymeric microspheres showing large potentials as adsorbents in wastewater treatment. Also importantly, the reactive aldehyde groups may enable the microspheres to be used as novel materials for immobilizing biomacromolecules, e.g. enzymes.

  1. Modified composite microspheres of hydroxyapatite and poly(lactide-co-glycolide) as an injectable scaffold

    International Nuclear Information System (INIS)

    Hu, Xixue; Shen, Hong; Yang, Fei; Liang, Xinjie; Wang, Shenguo; Wu, Decheng

    2014-01-01

    The compound of hydroxyapatite-poly(lactide-co-glycolide) (HA-PLGA) was prepared by ionic bond between HA and PLGA. HA-PLGA was more stable than the simple physical blend of hydroxyapatite and poly(lactide-co-glycolide) (HA/PLGA). The surface of HA-PLGA microsphere fabricated by an emulsion–solvent evaporation method was rougher than that of HA/PLGA microspheres. Moreover, surface HA content of HA-PLGA microspheres was more than that of HA/PLGA microspheres. In vitro mouse OCT-1 osteoblast-like cell culture results showed that the HA-PLGA microspheres clearly promoted osteoblast attachment, proliferation and alkaline phosphatase activity. It was considered that surface rich HA component and rough surface of HA-PLGA microsphere enhanced cell growth and differentiation. The good cell affinity of the HA-PLGA microspheres indicated that they could be used as an injectable scaffold for bone tissue engineering.

  2. Preparation of magnetic core mesoporous shell microspheres with C18-modified interior pore-walls for fast extraction and analysis of phthalates in water samples.

    Science.gov (United States)

    Li, Zhongbo; Huang, Danni; Fu, Chinfai; Wei, Biwen; Yu, Wenjia; Deng, Chunhui; Zhang, Xiangmin

    2011-09-16

    In this study, core-shell magnetic mesoporous microspheres with C18-functionalized interior pore-walls were synthesized through coating Fe(3)O(4) microspheres with a mesoporous inorganic-organic hybrid layer with a n-octadecyltriethoxysilane (C18TES) and tetraethyl orthosilicate (TEOS) as the silica source and cetyltrimethylammonia bromide (CTAB) as a template. The obtained C18-functionalized Fe(3)O(4)@mSiO(2) microspheres possess numerous C18 groups anchored in the interior pore-walls, large surface area (274.7 m(2)/g, high magnetization (40.8 emu/g) and superparamagnetism, uniform mesopores (4.1 nm), which makes them ideal absorbents for simple, fast, and efficient extraction and enrichment of hydrophobic organic compounds in water samples. Several kinds of phthalates were used as the model hydrophobic organic compounds to systematically evaluate the performance of the C18-functionalized Fe(3)O(4)@mSiO(2) microspheres in extracting hydrophobic molecules by using a gas chromatography-mass spectrometry. Various parameters, including eluting solvent, the amounts of absorbents, extraction time and elution time were optimized. Hydrophobic extraction was performed in the interior pore of magnetic mesoporous microspheres, and the materials had the anti-interference ability to macromolecular proteins, which was also investigated in the work. Under the optimized conditions, C18-functionalized Fe(3)O(4)@mSiO(2) microspheres were successfully used to analyze the real water samples. The results indicated that this novel method was fast, convenient and efficient for the target compounds and could avoid being interfered by macromolecules. Copyright © 2011 Elsevier B.V. All rights reserved.

  3. Cryptosporidium Removal from Runoff by Active Carbon Filter with Coal Gangue

    OpenAIRE

    Ping Lu; Tao Yuan; Baojun Zhang

    2016-01-01

    Transport of Cryptosporidium in runoff will contaminate the surrounding water body. Cryptosporidium-sized microspheres and inactive Cryptosporidium parvum oocysts removal using an active carbon (AC) filter with/without coal gangue from the runoff was evaluated. Chemical composition of coal gangue was determined, and its performance as a water treatment material was tested. Results showed SiO2 was the dominant chemical component of coal gangue. Removal was only 20% for microspheres and 24% for...

  4. Evaluation of nonradioactive, colored microspheres for measurement of regional myocardial blood flow in dogs

    International Nuclear Information System (INIS)

    Hale, S.L.; Alker, K.J.; Kloner, R.A.

    1988-01-01

    Measurement of regional myocardial blood flow (RMBF) is crucial in experimental studies of myocardial ischemia and reperfusion in dogs. The standard measurement technique uses radioactive microspheres; however, not all institutions are able to dispose of radioactive waste and therefore cannot make use of this method. We tested a new, nonradioactive microsphere, labeled with colors instead of nuclides. Simultaneous blood flow measurements with two nuclide-labeled and two colored microspheres were performed after coronary occlusion in dogs. Both techniques show a within-method correlation of r greater than 0.98. Duplicate variability for paired RMBF values in 80 samples was 8.7 +/- 0.1% when computed with radioactive microspheres and 13.2 +/- 1.8% when computed with colored microspheres. There was a good correlation in the measurement of RMBF between the radioactive- and colored-microsphere methods (r = 0.98). The best-fitting linear regression line was expressed by the formula: Colored-microsphere RMBF = 1.11 (radioactive-microsphere RMBF)-0.02. When measured by colored microspheres, RMBF was approximately 8% higher than when computed with radioactive microspheres for blood flow values of 0-2 ml/min/g. When blood flow was increased pharmacologically to levels of 2-7.5 ml/min/g, colored microspheres yielded blood flow values 39% higher than the values computed by radioactive microspheres. We conclude that the nonradioactive, colored-microsphere method correlates with the radioactive technique, but at high flows, it yields values greater than those obtained with radioactive microspheres

  5. Surface modification of cyclomatrix polyphosphazene microsphere by thiol-ene chemistry and lectin recognition

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chen; Zhu, Xue-yan; Gao, Qiao-ling; Fang, Fei; Huang, Xiao-jun, E-mail: hxjzxh@zju.edu.cn

    2016-11-30

    Graphical abstract: A new synthetic route leading to polyphosphazene cyclomatrix microsphere with various functional groups has achieved via thiol-ene click modification. Herein, hexacholorocyclophosphazene (HCCP) crosslinked with bisphenol-S and 4,4′-diallyl bisphenol-S to generate broadly dispersed microspheres. Thiol-ene modification under UV irradiation not only presented high efficiency and flexibility for post-functionalization, but also imposed no harm on global morphology and crosslinked skeleton of such microspheres. - Highlights: • Functional polyphosphazene microspheres with high chemical flexibility were synthesized by thiol-ene modification. • Polyphosphazene microspheres possessed high thermal stability. • Glycosylated polyphosphazene microspheres showed affinity to lectin Con-A, which inferred potential application in biomedicine. - Abstract: A new synthetic route leading to functional polyphosphazene cyclomatrix microsphere has been developed via thiol-ene click modification. Hexacholorocyclophosphazene (HCCP) was crosslinked with both bisphenol-S and 4,4′-diallyl bisphenol-S to obtain vinyl polyphosphazene microspheres (VPZM) in order to ensure high crosslinking degree and introduce vinyl moieties. Compared to the microspheres obtained by HCCP and bisphenol-S, the size of VPZM was broadly dispersed from 400 nm to 1.40 μm. Thiol-ene click reactions were carried out to attach functional groups, such as glucosyl, carboxyl, ester and dodecyl groups onto polyphosphazene microspheres, which demonstrated no change in morphology and size after modification. Solid state NMR (SSNMR) and Fourier transform infrared spectoscopy (FT-IR) results showed that the vinyl moieties were introduced in the period of crosslinking and functionalization was also successful via click reactions. Moreover, the microspheres presented a little difference in thermal properties after modification. Concanavalin A (Con-A) fluorescent adsorption was also observed for

  6. Kinetics of the hydrothermal treatment of tannin for producing carbonaceous microspheres.

    Science.gov (United States)

    Braghiroli, F L; Fierro, V; Izquierdo, M T; Parmentier, J; Pizzi, A; Celzard, A

    2014-01-01

    Aqueous solutions of condensed tannins were submitted to hydrothermal carbonization (HTC) in a stainless steel autoclave, and the kinetics of hydrothermal carbon formation was investigated by changing several parameters: amount of tannin (0.5; 1.0; 1.5; 2.0 g in 16 mL of water), HTC temperature (130, 160, 180 and 200°C) and reaction times (from 1 to 720 h). The morphology and the structure of the tannin-based hydrothermal carbons were studied by TEM, krypton adsorption at -196°C and helium pycnometry. These materials presented agglomerated spherical particles, having surface areas ranging from 0.6 to 10.0 m(2) g(-1). The chemical composition of the hydrothermal carbons was found to be constant and independent of reaction time. HTC kinetics of tannin were determined and shown to correspond to first-order reaction. Temperature-dependent measurements led to an activation energy of 91 kJ mol(-1) for hydrothermal conversion of tannin into carbonaceous microspheres separable by centrifugation. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Carbon-dioxide storage in the subsurface: towards an understanding of crack development in the cap-rock including phase transition processes

    Science.gov (United States)

    Häberle, K.; Ehlers, W.

    2012-04-01

    Supercritical CO2 can be injected into deep saline aquifers to reduce the amount of CO2 in the atmosphere and thus, lessen the impact on the global warming. Qualified reservoirs should be in a sufficient depth to guarantee the thermodynamical environment for the supercritical state of CO2. Furthermore, an impermeable cap-rock layer must confine the reservoir layer, in order to collect the CO2 in the desired region. In CO2 storage it is crucial to guarantee the safety of the storage site and to eliminate possibilities of leakage. Therefore, deformation processes of the rock matrix and the cap-rock layer, which might be induced by the high pressure injection of CO2, must be investigated. The increase in stress may also cause crack development in the cap-rock layer. These could either be new developing fractures or the break-up of already existing but cemented cracks or faults. If such cracks occur, CO2 could migrate to shallower regions where the temperature and pressure cannot support the supercritical condition of the CO2 anymore. Thus, it is important to describe the phase transition process between supercritical, liquid and gaseous CO2. This requires a proper understanding of the thermodynamical behaviour of CO2 within the reservoir. The Theory of Porous Media (TPM) provides a useful continuum-mechanical basis to describe real natural systems in a thermodynamically consistent way. Hence, the TPM is applied to model multiphasic flow of CO2 and water and include elasto-plastic solid deformations of the porous matrix. The Peng-Robinson equation is implemented as a cubic equation of state to describe the phase behaviour of CO2 in the liquid, gaseous and supercritical region. However, in the two-phase region the isotherms show a horizontal section and kinks at the boiling and vapour curve. This cannot be represented by a continuously differentiable function such as the Peng-Robinson equation. To circumvent this problem, the Antoine equation provides additional

  8. Perfusion measurements with radioactively labelled microspheres

    International Nuclear Information System (INIS)

    Schosser, R.

    1980-01-01

    The technique and the evaluation of the microsphere-method are comprehensively represented in theory and practice. Some changes and new concepts are discussed, besides the known foundations and techniques, that assure an essential methodic improvement resp. practical simplifications. Two new formulas are derived within the frame of the theoretical principles, by which the absolute flux of shorts can be calculated, i.e. on the one hand in the case of known and on the other hand in the case of unknown applied amount of indicator. The determination of the optimal indicator dose is defined and formulated mathematically with respect to the experimental conditions to be expected. The matrix method was designed for the analysis of complex gamma spectra. Hereby there is no selective error accumulation in the case of low energy radio nuclids contrary to the so far exclusively used stripping technique. The number of possible error quantities was reduced by one resp. two variables. The error of particular radio nuclid components is quantitatively computed as standard deviation by means of the theory of approximated systems of linear equations. The external measurement of distance was developed. This technique is less susceptible for errors as the aliquota i.e. whole body measurement technique. Additionally less measurement time is needed. A flexible computer program for a desk top computer was developped for the evaluation. The data from the gamma spectrometer are recorded on tipe and automatically read in by the computer. The manual input are limited to the weights of the organs and some control parameter. The output is made by a clearly arranged table by means of a lineprinter. (orig./MG) [de

  9. Basophilic round bodies in gastric biopsies little known by pathologists: iatrogenic yttrium 90 microspheres deriving from selective internal radiation therapy.

    Science.gov (United States)

    Luo, Dong-Lan; Chan, John K C

    2013-10-01

    Selective internal radiation therapy is a relatively new technique that irradiates primary and metastatic liver cancer using yttrium 90 microspheres. Increasing reports have shown this to be a useful treatment for unresectable primary hepatocellular carcinoma and others metastases from colon, lung, breast, sarcoma, and ocular melanoma. On the other hand, more and more therapy-related complications have been described. Since the morphologic description of injured organs are relatively uncommon, we report 2 cases of selective internal radiation therapy-related gastric injury, which represent basophilic round bodies in gastric biopsies little known by pathologists. The appearances in esophagogastroduodenoscopy include gastrointestinal ulcer, edema, and bleeding. Histological findings are mucosal atrophy, mild to moderate cytologic atypia, edema of the stroma, and inflammatory infiltration. The most characteristic feature is the presence of round blue and dark microspheres in the stromal blood vessels.

  10. Removal combined with reduction of hexavalent chromium from aqueous solution by Fe-ethylene glycol complex microspheres

    Science.gov (United States)

    Zhang, Yong-Xing; Jia, Yong

    2016-12-01

    Three-dimensional Fe-ethylene glycol (Fe-EG) complex microspheres were synthesized by a facile hydrothermal method, and were characterized by field emission scanning electron microscopy and transmission electron microscopy. The adsorption as well as reduction properties of the obtained Fe-EG complex microspheres towards Cr(VI) ions were studied. The experiment data of adsorption kinetic and isotherm were fitted by nonlinear regression approach. In neutral condition, the maximum adsorption capacity was 49.78 mg g-1 at room temperature, and was increased with the increasing of temperature. Thermodynamic parameters including the Gibbs free energy, standard enthalpy and standard entropy revealed that adsorption of Cr(VI) was a feasible, spontaneous and endothermic process. Spectroscopic analysis revealed the adsorption of Cr(VI) was a physical adsorption process. The adsorbed CrO42- ions were partly reduced to Cr(OH)3 by Fe(II) ions and the organic groups in the Fe-EG complex.

  11. Fabrication of TiO2@Yeast-Carbon Hybrid Composites with the Raspberry-Like Structure and Their Synergistic Adsorption-Photocatalysis Performance

    Directory of Open Access Journals (Sweden)

    Dang Yu

    2013-01-01

    Full Text Available In the present work, we report the preparation and photocatalytic properties of TiO2@yeast-carbon with raspberry-like structure using a pyrolysis method. The products are characterized by field emission scanning electron microscopy (FE-SEM, energy dispersive spectrometry (EDS, X-ray diffraction (XRD, thermal gravimetric and differential thermal analysis (TGA-DTA, Fourier transformed infrared spectroscopy (FT-IR, and ultraviolet visible spectroscopy (UV-VIS, respectively. The results show that the hybrid TiO2@yeast-carbon microspheres have ordered elliptic shapes of uniform size (length = 3.5±0.3 μm; width = 2.5±0.5 μm. UV-VIS ascertains that the as-prepared microspheres possess an obvious light response in a wide range of 250–400 nm. In the decomposition of typical model pollutants including methylene blue and congo red, the hybrid composites exhibited excellent photocatalytic activity for the methylene blue due to the enhanced adsorption ability. Further investigation reveals that the combined effect of adsorption from the yeast-carbon core and photocatalytic degradation from the attached TiO2 nanoparticles were responsible for the improvement of the photocatalytic activities. Hereby, the raspberry-like TiO2@yeast-carbon has promising applications in water purification.

  12. Method for forming microspheres for encapsulation of nuclear waste

    Science.gov (United States)

    Angelini, Peter; Caputo, Anthony J.; Hutchens, Richard E.; Lackey, Walter J.; Stinton, David P.

    1984-01-01

    Microspheres for nuclear waste storage are formed by gelling droplets containing the waste in a gelation fluid, transferring the gelled droplets to a furnace without the washing step previously used, and heating the unwashed gelled droplets in the furnace under temperature or humidity conditions that result in a substantially linear rate of removal of volatile components therefrom.

  13. Hollow microspheres with a tungsten carbide kernel for PEMFC application.

    Science.gov (United States)

    d'Arbigny, Julien Bernard; Taillades, Gilles; Marrony, Mathieu; Jones, Deborah J; Rozière, Jacques

    2011-07-28

    Tungsten carbide microspheres comprising an outer shell and a compact kernel prepared by a simple hydrothermal method exhibit very high surface area promoting a high dispersion of platinum nanoparticles, and an exceptionally high electrochemically active surface area (EAS) stability compared to the usual Pt/C electrocatalysts used for PEMFC application.

  14. Preparation and Characterization of Colon-Specific Microspheres of ...

    African Journals Online (AJOL)

    Purpose: To prepare and evaluate colon specific drug delivery system of diclofenac sodium for highly localized delivery to the colon. Methods: The colon specific drug delivery system was prepared as matrix-type microspheres using Ethyl Cellulose (EC), Cellulose Acetate Phthalate (CAP), and Eudragit L 100-55 by the ...

  15. Acylation of arginine in goserelin-loaded PLGA microspheres

    NARCIS (Netherlands)

    Shirangi, Mehrnoosh; Hennink, Wim E.; Somsen, Govert W.; Van Nostrum, Cornelus F.

    2016-01-01

    Acylation of peptides is a well-known but unwanted phenomenon in polyester matrices such as poly(d,l-lactic-co-glycolic acid) (PLGA) microspheres used as controlled release formulations. Acylation normally occurs on lysine residues and the N-terminus of the peptide. The purpose of the present work

  16. Formulation and evaluation of matrix microspheres for simultaneous ...

    African Journals Online (AJOL)

    The prepared microspheres were characterized for their micromeritic properties and drug loading, as well as by infrared spectroscopy (IR), differential scanning calorimetry (DSC), x-ray powder diffractometry (XRD) and scanning electron microscopy (SEM). The in vitro release studies were performed in pH 7.4, phosphate ...

  17. Preparation and characterization of microspheres of albumin-heparin conjugates

    NARCIS (Netherlands)

    Kwon, Glen S.; Bae, You Han; Kim, Sung Wan; Cremers, Harry; Cremers, H.F.M.; Feijen, Jan

    1991-01-01

    Albumin-heparin microspheres have been prepared as a new drug carrier. A soluble albumin-heparin conjugate was synthesized by forming amide bonds between human serum albumin and heparin. After purification the albumin-heparin conjugate was crosslinked in a water-in-oil emulsion to form

  18. Fabrication of hierarchical β-Co(OH)2 microspheres via ...

    Indian Academy of Sciences (India)

    Administrator

    Abstract. Hierarchical β-Co(OH)2 microspheres with 20–50 µm diameter assembled from nanoplate building blocks were successfully fabricated via a hydrothermal process in the presence of a cation surfactant cetyl- trimethylammonium bromide (CTAB). The products are characterized in detail by multiform techniques: X-.

  19. Treatment of liver tumors with yttrium-90 microspheres alone

    International Nuclear Information System (INIS)

    Blanchard, R.J.W.; Morrow, I.M.; Sutherland, J.B.

    1989-01-01

    Fifteen patients with liver metastases and one patient with hepatoma were treated by infusing 15 μm diameter plastic microspheres containing yttrium-90 into the hepatic artery. Twenty additional patients were screened but were found to be unsuitable for treatment. Follow-up angiography was done in 13 of the 16 treated patients. In five patients there was a reduction in tumor volume by more than 50% and in another two patients there was a smaller reduction. In six patients gastritis or gastric ulceration occurred and in three this was demonstrated to be due to unintended infusion of microspheres into the gastric circulation. For patients treated with yttrium-90 microspheres, mean survival time after referral was 62 weeks and in the untreated group it was 30 weeks, although this difference was not significant. We conclude that yttrium-90 microspheres alone can effect reduction in the size of liver tumors in some patients in whom their use is feasible. (13 refs., tab., 3 figs.)

  20. Formulation and Evaluation of Microspheres Based on Gelatin ...

    African Journals Online (AJOL)

    Purpose: Swellable microspheres based on polymers or their admixtures are frequently employed as drug delivery systems to achieve a controlled release and site-specific targeting of the incorporated drug. The objective of the present study was to enhance the rectal delivery of cefuroxime sodium by entrapping it into ...

  1. Biodegradable poly(lactic acid) microspheres containing total ...

    Indian Academy of Sciences (India)

    Administrator

    the bio-availability of conventional drugs with minimum side-effects, new drug delivery systems continue to .... Drug microspheres, 100 mg, were suspended in 5 ml ethanol at room temperature for about 10 min by ultra ... containing 5 ml water were incubated in a bath and then stirred at 100 rpm in phosphate buffered saline ...

  2. Preparation of microspheres and microcapsules by interfacial polycondensation techniques.

    Science.gov (United States)

    Arshady, R

    1989-01-01

    A methodological review of the production of microspheres/microcapsules by interfacial polycondensation is presented and the mechanisms of particle and capsule formation are discussed. Procedures for interfacial polycondensation employed for the preparation of microspheres/microcapsules involve the polycondensation of two complementary monomers in a two phase suspension system. Each of the two complementary monomers resides largely in one of the two immiscible phases in the suspension system. The resulting polycondensate, which is formed at or on one side of the interface, may, or may not, be soluble in the droplet phase. If the polymer is soluble in the droplets, particulate microspheres or monolithic microcapsules are formed, i.e. particle forming interfacial polycondensation. If the polymer is insoluble in the droplets, it forms a membrane around them, and the droplets are thus individually encapsulated by the polymer. This leads to the formation of capsular microspheres or reservoir microcapsules, and hence capsule forming interfacial polycondensation. A major example of particle forming interfacial polycondensation is that of phosgene with bisphenol A recently developed for the production of polycarbonate resins in particle form. Capsule forming interfacial polycondensation is widely used to prepare polyamide (nylon) microcapsules containing proteins, pharmaceuticals, etc.

  3. Novel fluorescent poly(glycidyl methacrylate) - silica microspheres

    Czech Academy of Sciences Publication Activity Database

    Grama, Silvia; Boiko, N.; Bilyy, R.; Klyuchivska, O.; Antonyuk, V.; Stoika, R.; Horák, Daniel

    2014-01-01

    Roč. 56, July (2014), s. 92-104 ISSN 0014-3057 R&D Projects: GA MŠk EE2.3.30.0029; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61389013 Keywords : microspheres * silica * poly(glycidyl methacrylate) Subject RIV: CE - Biochemistry Impact factor: 3.005, year: 2014

  4. Improved antireflection coated microspheres for biological applications of optical tweezers

    Science.gov (United States)

    Ferro, Valentina; Sonnberger, Aaron; Abdosamadi, Mohammad K.; McDonald, Craig; Schäffer, Erik; McGloin, David

    2016-09-01

    The success of optical tweezers in cellular biology1 is in part due to the wide range of forces that can be applied, from femto- to hundreds of pico-Newtons; nevertheless extending the range of applicable forces to the nanoNewton regime opens access to a new set of phenomena that currently lie beyond optical manipulation. A successful approach to overcome the conventional limits on trapping forces involves the optimization of the trapped probes. Jannasch et al.2 demonstrated that an anti-reflective shell of nanoporous titanium dioxide (aTiO2, nshell = 1.75) on a core particle made out of titanium dioxide in the anatase phase (cTiO2, ncore = 2.3) results in trappable microspheres capable to reach forces above 1 nN. Here we present how the technique can be further improved by coating the high refractive index microspheres with an additional anti-reflective shell made out of silica (SiO2). This external shell not only improves the trap stability for microspheres of different sizes, but also enables the use of functionalization techniques already established for commercial silica beads in biological experiments. We are also investigating the use of these new microspheres as probes to measure adhesion forces between intercellular adhesion molecule 1 (ICAM-1) and lymphocyte function-associated antigen 1 (LFA-1) in effector T-Cells and will present preliminary results comparing standard and high-index beads.

  5. Development of a roundness measuring system for microspheres

    International Nuclear Information System (INIS)

    Fan, Kuang-Chao; Wang, Na; Wang, Zhi-Wei; Zhang, Hui

    2014-01-01

    In the field of micro/nano technology, microspheres are often used as the tip-ball of a measuring stylus, such as in micro/nano coordinate measuring machines (CMMs). Conventional tactile probes adopt ruby or steel balls with diameters in the range of several millimeters to 0.3 mm. For a micro-CMM, the required probing ball is as small as possible in order to be inserted into a small groove for side wall measurement. The exact diameter of the tip-ball has to be calibrated for radius compensation and its roundness error has to be qualified. A roundness measuring system for microspheres is developed in this study. Two small Michelson interferometers are designed for direct measurement of microsphere diameter from both sides, being a two-point method. By rotating the measured sphere and reading the displacement shifts of the two interferometers, the run-out of the sphere can be eliminated. The resolution of the developed system can reach 1 nm and the accuracy can reach 10 nm. Two microspheres are tested with good repeatability. This system can also be used for macrosphere measurement. (paper)

  6. Development of a roundness measuring system for microspheres

    Science.gov (United States)

    Fan, Kuang-Chao; Wang, Na; Wang, Zhi-Wei; Zhang, Hui

    2014-06-01

    In the field of micro/nano technology, microspheres are often used as the tip-ball of a measuring stylus, such as in micro/nano coordinate measuring machines (CMMs). Conventional tactile probes adopt ruby or steel balls with diameters in the range of several millimeters to 0.3 mm. For a micro-CMM, the required probing ball is as small as possible in order to be inserted into a small groove for side wall measurement. The exact diameter of the tip-ball has to be calibrated for radius compensation and its roundness error has to be qualified. A roundness measuring system for microspheres is developed in this study. Two small Michelson interferometers are designed for direct measurement of microsphere diameter from both sides, being a two-point method. By rotating the measured sphere and reading the displacement shifts of the two interferometers, the run-out of the sphere can be eliminated. The resolution of the developed system can reach 1 nm and the accuracy can reach 10 nm. Two microspheres are tested with good repeatability. This system can also be used for macrosphere measurement.

  7. Fabrication of periodically ordered diamond nanostructures by microsphere lithography

    Czech Academy of Sciences Publication Activity Database

    Domonkos, Mária; Ižák, Tibor; Štolcová, L.; Proška, J.; Kromka, Alexander

    2014-01-01

    Roč. 251, č. 12 (2014), s. 2587-2592 ISSN 0370-1972 R&D Projects: GA ČR(CZ) GBP108/12/G108 Institutional support: RVO:68378271 Keywords : CVD growth * diamond * microsphere lithography * selective area deposition Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.489, year: 2014

  8. PtNi nanoparticles embedded in porous silica microspheres as ...

    Indian Academy of Sciences (India)

    SEM, EDS, TEM, FTIR, XRD, ICP-AES, XPS and nitrogen adsorption/desorption analysis were employed to systematically investigate the morphology and structure of the obtained SiO2 microspheres and SiO₂/PtNi nanocatalysts. Results show that uniform PtNi nanoparticles can be homogeneously and firmly embedded ...

  9. Mucoadhesive microspheres: a promising tool in drug delivery.

    Science.gov (United States)

    Patil, Sanjay B; Sawant, Krutika K

    2008-10-01

    Mucoadhesive polymers have recently gained interest among pharmaceutical scientists as a means of improving drug delivery by promoting the residence time and contact time of the dosage form with the mucous membranes. Mucoadhesion is the process whereby synthetic and natural polymers adhere to mucosal surfaces in the body. If these materials are then incorporated into pharmaceutical formulations, drug absorption by mucosal cells may be enhanced or the drug will be released at the site for an extended period of time. Microspheres, in general, have the potential to be used for targeted and controlled release drug delivery; however, coupling of mucoadhesive properties to microspheres has additional advantages like, a much more intimate contact with the mucus layer, efficient absorption and enhanced bioavailability of the drugs due to a high surface to volume ratio. The present review describes the potential applications of mucoadhesive microspheres as a novel carrier system to improve drug delivery by various routes of administration like buccal, oral, nasal, ocular, vaginal and rectal, either for systemic or for local effects. The mucoadhesive polymers, methods of preparation of microspheres and their in vitro and in vivo evaluation are also described.

  10. Hydrogel microspheres from biodegradable polymers as drug delivery systems

    Science.gov (United States)

    A series of hydrogel microspheres were prepared from pectin, a hydrophilic biopolymer, and zein, a hydrophobic biopolymer, at varying weight ratios. The hydrogel formulation was conducted in the presence of calcium or other divalent metal ions at room temperature under mild conditions. Studies of ...

  11. Recombinant Gelatin Microspheres : Novel Formulations for Tissue Repair?

    NARCIS (Netherlands)

    Tuin, Annemarie; Kluijtmans, Sebastiaan G.; Bouwstra, Jan B.; Harmsen, Martin C.; Van Luyn, Marja J. A.

    Microspheres (MSs) can function as multifunctional scaffolds in different approaches of tissue repair (TR), as a filler, a slow-release depot for growth factors, or a delivery vehicle for cells. Natural cell adhesion-supporting extracellular matrix components like gelatin are good materials for

  12. Albumin-heparin microspheres as carriers for cytostatic agents

    NARCIS (Netherlands)

    Cremers, Harry; Feijen, Jan; Kwon, G.; Bae, Y.H.; Kim, S.W.; Noteborn, H.P.J.M.; Mcvie, J.G.

    1990-01-01

    Much work has been done on adriamycin-loaded albumin microspheres (Alb-MS) for chemoembolization [1–4], the rationale being that site-specific drug delivery may increase the therapeutic efficacy of the drug. Alb-Ms are being investigated because of their biocompatibility and because the degradation

  13. Commonly used numbers of microspheres affect cardiac vascular resistance

    NARCIS (Netherlands)

    Zuurbier, Coert Jozef; Kruyver, Bart; Eerbeek, Otto; Mik, Egbert Gezinus; Ince, Can

    2003-01-01

    The main goal of the study was to examine how the microsphere technique affects the hemodynamics and mitochondrial energy status of the Langendorff-perfused rat heart. The hearts were perfused at a constant flow with Tyrode solution. NADH videofluorometry of the surface of the left ventricle was

  14. Development of activity standard for 90Y microspheres

    CSIR Research Space (South Africa)

    Mo, L

    2005-08-01

    Full Text Available 90Y is a therapeutic radiopharmaceuticals used in the treatment of liver cancer following implantation via a catheter in the hepatic artery, 90Y microspheres are embolised in the microvasculature of liver cancer where they irradiate the tumour by a...

  15. Effects of hepatic arterial yttrium 90 glass microspheres in dogs.

    Science.gov (United States)

    Wollner, I; Knutsen, C; Smith, P; Prieskorn, D; Chrisp, C; Andrews, J; Juni, J; Warber, S; Klevering, J; Crudup, J

    1988-04-01

    A 22-micron glass microsphere called TheraSphere (Theragenics Corp., Atlanta, GA) has been developed in which yttrium 89 oxide is incorporated into the glass matrix and is activated by neutron bombardment to form the beta-emitting isotope yttrium 90 (Y 90) before using the spheres as radiotherapeutic vehicles. The injection of up to 12 times (on a liver weight basis) the anticipated human dose of nonradioactive TheraSphere into the hepatic arteries of dogs was well tolerated and produced clinically silent alterations within centrolobular areas. The hepatic arterial (HA) injection of radioactive TheraSphere also produced portal changes similar to those observed in humans after external beam therapy. While the extent of damage increased with the delivered dose, radiation exposures in excess of 30,000 cGy did not cause total hepatic necrosis and were compatible with survival. No microspheres distributed to the bone marrow and absolutely no myelosuppression was encountered in any animal. Proposed hepatic exposures to humans of 5000 to 10,000 cGy by means of these microspheres, therefore, would appear to be feasible and tolerable. Radiotherapeutic microsphere administration preceded by regional infusion of a radiosensitizing agent and/or immediately following the redistribution of blood flow toward intrahepatic tumor by vasoactive agents can potentially yield a synergistic, highly selective attack on tumors confined to the liver.

  16. Sheet-on-sheet chrysanthemum-like C/FeS microspheres synthesized by one-step solvothermal method for high-performance sodium-ion batteries

    Science.gov (United States)

    Cao, Zhenjiang; Song, Huaihe; Cao, Bin; Ma, Jing; Chen, Xiaohong; Zhou, Jisheng; Ma, Zhaokun

    2017-10-01

    Chrysanthemum-like carbon/FeS microspheres (CL-C/FeS) are prepared from a one-step solvothermal method. The morphology and structure of the CL-C/FeS are characterized by X-ray diffraction, scanning electron microscopy and high-resolution transmission electron microscope. We note that the prepared CL-C/FeS microspheres exhibit the average diameter of 15 μm and possess a sheet-on-sheet structure. FeS nanosheets are stacked on the carbon sheets to form a 2D sheet-on-sheet structure, these 2D C/FeS nanosheets are self-assembled to form a 3D chrysanthemum-like morphology. Due to the unique structure, CL-C/FeS microspheres show the excellent sodium-storage performance of 500 mAh g-1 at 0.2 A g-1 and 260 mAh g-1 at 1 A g-1, which are higher than those of most reported values. Therefore, the CL-C/FeS with appropriate structure is expected to be a competitive choice for anode materials for sodium ion batteries.

  17. Synthesis of 3C–SiC nanowires by reaction of poly(ethylene terephthalate) waste with SiO2 microspheres

    International Nuclear Information System (INIS)

    Gao, Lei; Zhong, Hao; Chen, Qianwang

    2013-01-01

    Highlights: •The 3C–SiC nanowires have been synthesized by reaction of poly(ethylene terephthalate) (PET) waste and SiO 2 microspheres as primary reactant. •The recycling of PET wastes are fulfilled, and it is beneficial to the environment protection. •Increasing information will decrease quality if hospital costs are very different. •The prepared 3C–SiC nanowires have a good morphology. •Other polymer wastes, such as PE, PP, PVC, and PS, can also be managed with this method. -- Abstract: 3C–SiC nanowires have been synthesized by reaction of poly(ethylene terephthalate) (PET) waste with SiO 2 microspheres in supercritical carbon dioxide system at 650 °C for 3 h, followed by vacuum annealing at 1500 °C for 4 h. The product was characterized by X-ray diffraction, Raman spectroscopic, Field Emission Scanning Electron Microscopy, and High-resolution Electron Microscopy. The 3C–SiC nanowires are tens of microns in length and 30–150 nm in diameter. It is found that the reaction forming 3C–SiC nanowires take place in the inner of the carbon microspheres generated from PET. The formation mechanism of the 3C–SiC nanowires was discussed

  18. Yttrium-90 microspheres for the treatment of hepatocellular carcinoma.

    Science.gov (United States)

    Geschwind, Jean Francois H; Salem, Riad; Carr, Brian I; Soulen, Michael C; Thurston, Kenneth G; Goin, Kathleen A; Van Buskirk, Mark; Roberts, Carol A; Goin, James E

    2004-11-01

    Unresectable hepatocellular carcinoma is extremely difficult to treat. TheraSphere consists of yttrium-90 (a pure beta emitter) microspheres, which are injected into the hepatic arteries. This article reviews the safety and survival of patients with hepatocellular carcinoma who were treated with yttrium-90 microspheres. Eighty patients were selected from a database of 108 yttrium-90 microsphere-treated patients and were staged by using Child-Pugh, Okuda, and Cancer of the Liver Italian Program scoring systems. Patients were treated with local, regional, and whole-liver approaches. Survival from first treatment was analyzed with Kaplan-Meier and Cox regression methods. Adverse events and complications of treatment were coded by using the Southwest Oncology Group toxicity scoring system. Patients received liver doses ranging from 47 to 270 Gy. Thirty-two patients (40%) received more than 1 treatment. Survival correlated with pretreatment Cancer of the Liver Italian Program scores ( P = .002), as well as with the individual Cancer of the Liver Italian Program components, Child-Pugh class, alpha-fetoprotein levels, and percentage of tumor replacement. Patients classified as Okuda stage I (n = 54) and II (n = 26) had median survival durations and 1-year survival rates of 628 days and 63%, and 384 days and 51%, respectively ( P = .02). One patient died of liver failure judged as possibly related to treatment. Thus, in selected patients with hepatocellular carcinoma, yttrium-90 microsphere treatment is safe and well tolerated. On the basis of these results, a randomized controlled trial is warranted comparing yttrium-90 microsphere treatment with transarterial chemoembolization by using the Cancer of the Liver Italian Program system for prospective stratified randomization.

  19. Robust platforms for creating organic-inorganic nanocomposite microspheres: decorating polymer microspheres containing mussel-inspired adhesion layers with inorganic nanoparticles.

    Science.gov (United States)

    Satoh, H; Saito, Y; Yabu, H

    2014-12-07

    We describe a method for creating robust and stable core-shell polymer microspheres decorated with inorganic (IO) nanoparticles (NPs) by a self-organization process and heterocoagulation using a mussel-inspired polymer adhesive layer between the IO NPs and the microspheres.

  20. Infiltrated carbon foam composites

    Science.gov (United States)

    Lucas, Rick D. (Inventor); Danford, Harry E. (Inventor); Plucinski, Janusz W. (Inventor); Merriman, Douglas J. (Inventor); Blacker, Jesse M. (Inventor)

    2012-01-01

    An infiltrated carbon foam composite and method for making the composite is described. The infiltrated carbon foam composite may include a carbonized carbon aerogel in cells of a carbon foam body and a resin is infiltrated into the carbon foam body filling the cells of the carbon foam body and spaces around the carbonized carbon aerogel. The infiltrated carbon foam composites may be useful for mid-density ablative thermal protection systems.

  1. Industrial Waste-Derived Nanoparticles and Microspheres Can Be Potent Antimicrobial and Functional Ingredients

    Directory of Open Access Journals (Sweden)

    Manashi Das Purkayastha

    2014-01-01

    Full Text Available Rapeseed oilcake or press-cake is generated as bulk waste during oil extraction from oilseeds. Owing to its high protein content, further processing of oilcakes into vegetable protein generates large quantities of fibrous residue (“oil-and-protein” spent meal as by-product, which currently has very limited practical utility. Here, we report hydrothermal carbonization of this industrial waste to convert it into carbon nanoparticles, bestowed with multitude of functionalities. We demonstrate that these nanoparticles can be assembled into micrometer-sized spheres when precipitated from water by acetone. These microspheres, with their added feature of hemocompatibility, can be potentially utilized as an encapsulation vehicle for the protection of thermolabile compounds (such as protein; however, the secondary and tertiary features of the protein were marginally perturbed by the encapsulation process. The synthesized carbon nanoparticle was found to be an effective biocidal agent, exhibiting bacterial cellular damage and complex formation with the bacterial plasmid (evident from ethidium bromide exclusion assay, which are critical for cell survival. The results show the ability to convert industrial biowaste into useful nanomaterials for use in food industries and also suggest new scalable and simple approaches to improve environmental sustainability in industrial processes.

  2. One-pot hydrothermal growth of raspberry-like CeO{sub 2} on CuO microsphere as copper-based catalyst for Rochow reaction

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Zheying [School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Li, Jing [State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Shi, Laishun, E-mail: lshunsh@sdu.edu.cn [School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Ji, Yongjun, E-mail: yjji@ipe.ac.cn [State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Zhong, Ziyi [School of Chemical & Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore 637459 (Singapore); Su, Fabing, E-mail: fbsu@ipe.ac.cn [State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China)

    2015-12-30

    Graphical abstract: - Highlights: • Ce–CuO composites were prepared via a one-pot and template-free hydrothermal method. • Ce–CuO consisted of raspberry-like CeO{sub 2} particles dispersed on porous CuO microspheres. • CuO microspheres were formed by self-assembly of nanorods. • Ce–CuO exhibited superior catalytic activity for dimethyldichlorosilane synthesis. - Abstract: In this work, we prepared a novel structure comprising of raspberry-like CeO{sub 2} deposited on CuO microspheres (Ce–CuO) for Rochow reaction. The synthesis was carried out via a facile one-pot hydrothermal reaction without using any template, in which, the basic copper carbonate microspheres were first formed via self-assembly of basic copper carbonate nanorods, followed with deposition of cerium hydroxide. After calcination, they were transformed into Ce–CuO but still maintained the hierarchical structure, and meanwhile, mesoporous structure was formed (for simplicity, we will only state them as metal oxide in the following context). The samples were characterized by X-ray diffraction (XRD), temperature-programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM), and scanning electron microscopy (SEM) techniques. When used as a Cu-based catalyst, Ce–CuO exhibited superior catalytic property to the single CuO, CeO{sub 2} and their physically mixture in the Rochow reaction with dimethyldichlorosilane (M2) selectivity increased from ca. 65 to 83.7%. The higher M2 selectivity of Ce–CuO is mainly due to its larger surface area and the synergistic effect between CuO and CeO{sub 2}. This work demonstrates that catalytic performance of the Cu-based can be improved by adding Ce rare-earth element and by carefully controlling their structures.

  3. One-pot hydrothermal growth of raspberry-like CeO2 on CuO microsphere as copper-based catalyst for Rochow reaction

    International Nuclear Information System (INIS)

    Jin, Zheying; Li, Jing; Shi, Laishun; Ji, Yongjun; Zhong, Ziyi; Su, Fabing

    2015-01-01

    Graphical abstract: - Highlights: • Ce–CuO composites were prepared via a one-pot and template-free hydrothermal method. • Ce–CuO consisted of raspberry-like CeO 2 particles dispersed on porous CuO microspheres. • CuO microspheres were formed by self-assembly of nanorods. • Ce–CuO exhibited superior catalytic activity for dimethyldichlorosilane synthesis. - Abstract: In this work, we prepared a novel structure comprising of raspberry-like CeO 2 deposited on CuO microspheres (Ce–CuO) for Rochow reaction. The synthesis was carried out via a facile one-pot hydrothermal reaction without using any template, in which, the basic copper carbonate microspheres were first formed via self-assembly of basic copper carbonate nanorods, followed with deposition of cerium hydroxide. After calcination, they were transformed into Ce–CuO but still maintained the hierarchical structure, and meanwhile, mesoporous structure was formed (for simplicity, we will only state them as metal oxide in the following context). The samples were characterized by X-ray diffraction (XRD), temperature-programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM), and scanning electron microscopy (SEM) techniques. When used as a Cu-based catalyst, Ce–CuO exhibited superior catalytic property to the single CuO, CeO 2 and their physically mixture in the Rochow reaction with dimethyldichlorosilane (M2) selectivity increased from ca. 65 to 83.7%. The higher M2 selectivity of Ce–CuO is mainly due to its larger surface area and the synergistic effect between CuO and CeO 2 . This work demonstrates that catalytic performance of the Cu-based can be improved by adding Ce rare-earth element and by carefully controlling their structures.

  4. Removal combined with reduction of hexavalent chromium from aqueous solution by Fe-ethylene glycol complex microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yong-Xing [School of Physics and Electronic Information, Huaibei Normal University, Huaibei 235000 (China); Jia, Yong, E-mail: yjiaahedu@163.com [School of Pharmacy, Anhui University of Chinese Medicine, Hefei 230012 (China)

    2016-12-15

    Highlights: • Fe-EG complex microspheres were synthesized by a hydrothermal method. • The removal properties towards Cr(VI) ions were investigated. • The adsorption and reduction mechanism was revealed by FTIR and XPS. - Abstract: Three-dimensional Fe-ethylene glycol (Fe-EG) complex microspheres were synthesized by a facile hydrothermal method, and were characterized by field emission scanning electron microscopy and transmission electron microscopy. The adsorption as well as reduction properties of the obtained Fe-EG complex microspheres towards Cr(VI) ions were studied. The experiment data of adsorption kinetic and isotherm were fitted by nonlinear regression approach. In neutral condition, the maximum adsorption capacity was 49.78 mg g{sup −1} at room temperature, and was increased with the increasing of temperature. Thermodynamic parameters including the Gibbs free energy, standard enthalpy and standard entropy revealed that adsorption of Cr(VI) was a feasible, spontaneous and endothermic process. Spectroscopic analysis revealed the adsorption of Cr(VI) was a physical adsorption process. The adsorbed CrO{sub 4}{sup 2−} ions were partly reduced to Cr(OH){sub 3} by Fe(II) ions and the organic groups in the Fe-EG complex.

  5. Radiation microsphere-induced GI ulcers after selective internal radiation therapy for hepatic tumors: an underrecognized clinical entity.

    Science.gov (United States)

    Konda, Amulya; Savin, Michael A; Cappell, Mitchell S; Duffy, Michael C

    2009-09-01

    Intra-arterial infusion of yttrium-90 (Y-90) microspheres is locoregional radiation therapy for unresectable hepatic neoplasms. Literature on GI complications of this novel therapy is sparse. Clinically and pictorially characterize selective internal radiation therapy (SIRT)-induced GI injury and review the published literature. Retrospective chart analysis. Single-center tertiary referral community hospital. One hundred three patients treated with SIRT for hepatic neoplasms between 2006 and 2008. SIRT for unresectable hepatic neoplasms followed by upper endoscopy with biopsy in symptomatic patients. GI ulcers after SIRT. Five patients with suspected GI injury after SIRT were identified. Significant postprocedural symptoms included nausea/vomiting, odynophagia, hematemesis, and melena. Radiation ulcers occurred mostly in the gastric antrum, pylorus, and duodenum. Biopsy specimens of ulcer margins in 4 patients showed pathognomonic radiation microspheres. Angiographic review of the fifth patient revealed a previously unrecognized arterial branch supplying the corresponding region of GI ulceration noted on endoscopy. Small retrospective study and follow-up limited by terminal disease states in most patients. The reported incidence of GI complications after SIRT for hepatic neoplasia varies from 3% to 24% of patients. Incidence can be minimized by strict adherence to published SIRT protocols. Diagnosis requires a high degree of clinical suspicion along with endoscopy and biopsy of ulcer margins. Characteristic radiation microspheres in biopsy specimens are pathognomonic. Gastroenterologists and pathologists must be cognizant of this complication.

  6. Simulation Model of Microsphere Distribution for Selective Internal Radiation Therapy Agrees With Observations.

    Science.gov (United States)

    Högberg, Jonas; Rizell, Magnus; Hultborn, Ragnar; Svensson, Johanna; Henrikson, Olof; Mölne, Johan; Gjertsson, Peter; Bernhardt, Peter

    2016-10-01

    To perform a detailed analysis of microsphere distribution in biopsy material from a patient treated with (90)Y-labeled resin spheres and characterize microsphere distribution in the hepatic artery tree, and to construct a novel dichotomous bifurcation model for microsphere deposits and evaluate its accuracy in simulating the observed microsphere deposits. Our virtual model consisted of arteries that successively branched into 2 new generations of arteries at 20 nodes. The artery diameter exponentially decreased from the lowest generation to the highest generation. Three variable parameters were optimized to obtain concordance between simulations and measure microsphere distributions: an artery coefficient of variation (ACV) for the diameter of all artery generations and the microsphere flow distribution at the nodes; a hepatic tree distribution volume (HDV) for the artery tree; and an artery diameter reduction (ADR) parameter. The model was tested against previously measured activity concentrations in 84 biopsies from the liver of 1 patient. In 16 of 84 biopsies, the microsphere distribution regarding cluster size and localization in the artery tree was determined via light microscopy of 30-μm sections (mean concentration, 14 microspheres/mg; distributions divided into 3 groups with mean microsphere concentrations of 4.6, 14, and 28 microspheres/mg). Single spheres and small clusters were observed in terminal arterioles, whereas large clusters, up to 450 microspheres, were observed in larger arterioles. For 14 microspheres/mg, the optimized parameter values were ACV=0.35, HDV = 50 cm(3), and ADR=6 μm. For 4.6 microspheres/mg, ACV and ADR decreased to 0.26 and 0 μm, respectively, whereas HDV increased to 130 cm(3). The opposite trend was observed for 28 microspheres/mg: ACV = 0.49, HDV = 20 cm(3), and ADR = 8 μm. Simulations and measurements reveal that microsphere clusters are larger and more common in volumes with high microsphere concentrations

  7. Simulation Model of Microsphere Distribution for Selective Internal Radiation Therapy Agrees With Observations

    Energy Technology Data Exchange (ETDEWEB)

    Högberg, Jonas, E-mail: jonas.hogberg@radfys.gu.se [Department of Radiation Physics, Sahlgrenska Academy, University of Gothenburg, Gothenburg (Sweden); Rizell, Magnus [Department of Surgery, Sahlgrenska University Hospital, Gothenburg (Sweden); Hultborn, Ragnar; Svensson, Johanna [Department of Oncology, Sahlgrenska University Hospital, Gothenburg (Sweden); Henrikson, Olof [Department of Radiology, Sahlgrenska University Hospital, Gothenburg (Sweden); Mölne, Johan [Department of Pathology, Sahlgrenska University Hospital, Gothenburg (Sweden); Gjertsson, Peter [Department of Clinical Physiology, Sahlgrenska University Hospital, Gothenburg (Sweden); Bernhardt, Peter [Department of Radiation Physics, Sahlgrenska Academy, University of Gothenburg, Gothenburg (Sweden); Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg (Sweden)

    2016-10-01

    Purpose: To perform a detailed analysis of microsphere distribution in biopsy material from a patient treated with {sup 90}Y-labeled resin spheres and characterize microsphere distribution in the hepatic artery tree, and to construct a novel dichotomous bifurcation model for microsphere deposits and evaluate its accuracy in simulating the observed microsphere deposits. Methods and Materials: Our virtual model consisted of arteries that successively branched into 2 new generations of arteries at 20 nodes. The artery diameter exponentially decreased from the lowest generation to the highest generation. Three variable parameters were optimized to obtain concordance between simulations and measure microsphere distributions: an artery coefficient of variation (ACV) for the diameter of all artery generations and the microsphere flow distribution at the nodes; a hepatic tree distribution volume (HDV) for the artery tree; and an artery diameter reduction (ADR) parameter. The model was tested against previously measured activity concentrations in 84 biopsies from the liver of 1 patient. In 16 of 84 biopsies, the microsphere distribution regarding cluster size and localization in the artery tree was determined via light microscopy of 30-μm sections (mean concentration, 14 microspheres/mg; distributions divided into 3 groups with mean microsphere concentrations of 4.6, 14, and 28 microspheres/mg). Results: Single spheres and small clusters were observed in terminal arterioles, whereas large clusters, up to 450 microspheres, were observed in larger arterioles. For 14 microspheres/mg, the optimized parameter values were ACV=0.35, HDV = 50 cm{sup 3}, and ADR=6 μm. For 4.6 microspheres/mg, ACV and ADR decreased to 0.26 and 0 μm, respectively, whereas HDV increased to 130 cm{sup 3}. The opposite trend was observed for 28 microspheres/mg: ACV = 0.49, HDV = 20 cm{sup 3}, and ADR = 8 μm. Conclusion: Simulations and measurements reveal that microsphere clusters are

  8. 18F-labeled resin microspheres as surrogates for 90Y resin microspheres used in the treatment of hepatic tumors: a radiolabeling and PET validation study

    Science.gov (United States)

    Selwyn, R. G.; Avila-Rodriguez, M. A.; Converse, A. K.; Hampel, J. A.; Jaskowiak, C. J.; McDermott, J. C.; Warner, T. F.; Nickles, R. J.; Thomadsen, B. R.

    2007-12-01

    90Y-labeled resin microspheres (SIR-Spheres®) are currently used to treat patients with primary and metastatic solid liver tumors. This treatment is typically palliative since patients have exhausted all other standard treatment options. Improving the quality of life and extending patient survival are typical benchmarks for tracking patient response. However, the current method for predicting microsphere biodistributions with 99mTc-labeled macroaggregated albumin (MAA) does not correlate well with patient response. This work presents the development of a new 18F-labeled resin microsphere to serve as a surrogate for the treatment microsphere and to employ the superior resolution and sensitivity of positron emission tomography (PET). The 18F microsphere biodistributions were determined in a rabbit using PET imaging and histological review. The PET-based uptake ratio was shown to agree with the histological findings to better than 3%. In addition, the radiolabeling process was shown to be rapid, efficient and relatively stable in vivo.

  9. Effect of chitosan-coated alginate microspheres on the permeability of Caco-2 cell monolayers.

    Science.gov (United States)

    Silva, Catarina M; Veiga, Francisco; Ribeiro, António J; Zerrouk, Naïma; Arnaud, Philippe

    2006-10-01

    Alginate microspheres were prepared by emulsification/internal gelation and coated with chitosan. The ability of chitosan-coated alginate microspheres to increase the paracellular transport across Caco-2 cell monolayers was evaluated in comparison to uncoated microspheres and chitosan solutions. Transport studies were performed by using a permeability marker, Lucifer Yellow (LY), and by measuring the transepithelial electric resistance (TEER) variations. Furthermore, the occurrence of cytotoxic effects was assessed by evaluating neutral red uptake in viable cells and lactate dehydrogenase (LDH) release from damaged cells. A 3-fold increase on LY permeability was obtained for coated microspheres when compared to chitosan solutions. TEER variations were in agreement with permeability results. Chitosan solutions exhibited a dose-dependent toxicity, but coated microspheres did not decrease the viability of cells. Chitosan-coated alginate microspheres have potential to be used as carriers of poorly absorbable hydrophilic drugs to the intestinal epithelia and possibly increase their oral bioavailability.

  10. Use of spray-dried zirconia microspheres in the separation of immunoglobulins from cell culture supernatant.

    Science.gov (United States)

    Subramanian, A; Carr, P W; McNeff, C V

    2000-08-18

    A method suitable for the isolation of monoclonal antibodies (MAbs) on novel zirconia microspheres (20-30 microm) is described. Zirconia microspheres were generated by spray drying colloidal zirconia. Spray-dried zirconia microspheres were further classified and characterized by X-ray diffraction, BET porosimetry and scanning electron microscopy. Spray-dried zirconia microspheres were modified with ethylenediamine-N,N'-tetra(methylenephosphonic) acid (EDTPA) to create a cation-exchange chromatographic support. The chromatographic behavior of a semi-preparative column packed with EDTPA-modified zirconia microspheres was evaluated and implications for scale-up are provided. EDTPA-modified zirconia microspheres were further used to purify MAbs from cell culture supernatant. Analysis by enzyme linked immunosorbent assay and gel electrophoresis demonstrate that MAbs can be recovered from a cell culture supernatant at high yield (92-98%) and high purity (>95%) in a single chromatographic step.

  11. Recent advances in polymeric microspheres for parenteral drug delivery--part 1.

    Science.gov (United States)

    Mao, Shirui; Guo, Chunqiang; Shi, Yi; Li, Luk Chiu

    2012-09-01

    Polymeric microspheres have been established as a valuable parenteral drug delivery system for sustained release of therapeutic agents via subcutaneous or intramuscular injection. Biodegradable polymers which are either synthetic or from natural sources are reviewed with respect to recent advances in exploring their applications for microsphere fabrications. New information on the impact of formulation variables on the properties of microspheres formed by an emulsion method was also presented. The characterization of microspheres using advanced physical analytical techniques was also reviewed and the utilization of the information in assessing in vivo performance of the product was also highlighted. The broad clinical use of microspheres for delivery of therapeutic agents in particular biologics such as proteins has not been realized commercially. The limited availability of biodegradable polymers with a long history of regulatory approval and the challenges in gaining regulatory approval of a new polymer have hindered the development of microspheres for parenteral drug delivery.

  12. Direct preparation of La2Zr2O7 microspheres by cathode plasma electrolysis.

    Science.gov (United States)

    Liu, Chenxu; Zhang, Jin; Deng, Shunjie; Wang, Peng; He, Yedong

    2016-07-15

    La2Zr2O7 microspheres were directly prepared by cathode plasma electrolysis (CPE) in the electrolyte of Zr(NO3)4·5H2O and La(NO3)3·6H2O. Compared with high temperature sintering methods, the energy of plasma was completely used by CPE and made it possible to prepare the microspheres without calcining. The diameters of microspheres were mostly in the range of 0.5-5μm and the microspheres consisted of fluorite and pyrochlore structures of La2Zr2O7. Moreover, the microspheres possessed potential photocatalytic activity and fluorescence property, owing to the high crystallinity and large surface area of the microspheres. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Functional energy nanocomposites surfaces based on mesoscopic microspheres, polymers and graphene flakes

    Science.gov (United States)

    Alekseev, S. A.; Dmitriev, A. S.; Dmitriev, A. A.; Makarov, P. G.; Mikhailova, I. A.

    2017-11-01

    In recent years, there has been a great interest in the development and creation of new functional energy materials, including for improving the energy efficiency of power equipment and for effectively removing heat from energy devices, microelectronics and optoelectronics (power micro electronics, supercapacitors, cooling of processors, servers and Data centers). In this paper, the technology of obtaining a new nanocomposite based on mesoscopic microspheres, polymers and graphene flakes is considered. The methods of sequential production of functional materials from graphite flakes of different volumetric concentration using polymers based on epoxy resins and polyimide, as well as the addition of a mesoscopic medium in the form of monodisperse microspheres are described. The data of optical and electron microscopy of such nanocomposites are presented, the main problems in the appearance of defects in such materials are described, the possibilities of their elimination by the selection of different concentrations and sizes of the components. Data are given on the measurement of the hysteresis of the contact angle and the evaporation of droplets on similar substrates. The results of studying the mechanical, electrophysical and thermal properties of such nanocomposites are presented. Particular attention is paid to the investigation of the thermal conductivity of these nanocomposites with respect to the creation of thermal interface materials for cooling devices of electronics, optoelectronics and power engineering.

  14. Cholecystitis after yttrium-90 resin microsphere radioembolization treatment: Clinical and pathologic findings.

    Science.gov (United States)

    Parakh, Sagun; Gananadha, Sivakumar; Allen, Robert; Yip, Desmond

    2016-07-01

    Radioembolization with yttrium microspheres is an established therapeutic modality for primary and secondary hepatic malignancies, with studies demonstrating improved overall survival. There remains a paucity of data on cholecystitis as a complication of radioembolization. We describe a small series of patients who developed cholecystitis as a result of radioembolization. Patients who had developed cholecystitis as a complication of radioembolization in our institution between 2001 and 2012 were retrospectively reviewed. Patient demographics, cancer details including treatment history, and procedural details of radioembolization and complications of cholecystitis were collected. Of 74 patients who underwent radioembolization using yttrium-90emitting microspheres, four (5.4%) presented with acute cholecystitis as a result of their treatment. All patients presented over 4 weeks following radioembolization and did not settle with conservative treatment. At surgery, the gallbladder was fibrotic and contracted in all cases making surgery difficult. The incidence of symptomatic radiation cholecystitis after radioembolization is low, and prophylactic cholecystectomy is not routinely recommended for patients undergoing radioembolization. Radiation cholecystitis should be suspected in patients presenting with symptoms of biliary colic or cholecystitis following radioembolization. Early cholecystectomy can be considered in patients undergoing surgery for other indications, especially in high-risk surgical patients in whom there is a high likelihood of radioembolization in the future as they do not respond to conservative treatment. Copyright © 2015. Published by Elsevier Taiwan.

  15. Adsorption behavior and mechanism of ibuprofen onto BiOCl microspheres with exposed {001} facets.

    Science.gov (United States)

    Li, Jian; Sun, Shiye; Chen, Rong; Zhang, Tuqiao; Ren, Bangxing; Dionysiou, Dionysios D; Wu, Zhejian; Liu, Xiaowei; Ye, Miaomiao

    2017-04-01

    BiOCl microspheres with exposed {001} facets have been synthesized through a simple solvothermal method. The adsorption and photocatalytic activities of BiOCl microspheres were evaluated by removal of ibuprofen (IBP) as the model reaction. Parameters including IBP concentration, BiOCl dosage, and inorganic ions were investigated to reveal the role of adsorption in BiOCl-based photocatalysis. We found that the high IBP removal rate by BiOCl is not due to photocatalytic oxidation but to surface adsorption. The combination of ICP/MS, IC, XPS, and FT-IR results directly proved that anion exchange between dissociated IBP and Cl accompanied by the formation of surface complex (O-Bi-OOC-C 12 H 17 ) onto the BiOCl surface is the main adsorption mechanism. In addition, we also demonstrated that organic compounds with carboxyl group (-COOH) such as diclofenac, benzoic acid, and p-phthalic acid can be adsorbed by BiOCl while organic compounds without carboxyl group such as carbamazepine, nitrobenzene, and p-chloronitrobenzene cannot be adsorbed. We believe that the BiOCl adsorption behavior and mechanism should be considered when discussing its photocatalytic mechanism.

  16. A general approach to mesoporous metal oxide microspheres loaded with noble metal nanoparticles

    KAUST Repository

    Jin, Zhao

    2012-04-26

    Catalytic microspheres: A general approach is demonstrated for the facile preparation of mesoporous metal oxide microspheres loaded with noble metal nanoparticles (see TEM image in the picture). Among 18 oxide/noble metal catalysts, TiO 2/0.1 mol Pd microspheres showed the highest turnover frequency in NaBH 4 reduction of 4-nitrophenol (see picture). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Release of proteins via ion exchange from albumin-heparin microspheres

    OpenAIRE

    Kwon, Glen S.; Bae, You Han; Cremers, H.F.M.; Cremers, Harry; Feijen, Jan; Kim, Sung Wan

    1992-01-01

    Albumin-heparin and albumin microspheres were prepared as ion exchange gels for the controlled release of positively charged polypeptides and proteins. The adsorption isotherms of chicken egg and human lysozyme, as model proteins, on microspheres were obtained. An adsorption isotherm of chicken egg lysozyme on albumin-heparin microspheres was linear until saturation was abruptly reached, The adsorption isotherms of human lysozyme at low and high ionic strength were typical of adsorption isoth...

  18. Fabrication of uranium dioxide ceramic pellets with controlled porosity from oxide microspheres

    Science.gov (United States)

    Remy, E.; Picart, S.; Delahaye, T.; Jobelin, I.; Dugne, O.; Bisel, I.; Blanchart, P.; Ayral, A.

    2014-05-01

    This study concerns the fabrication of uranium oxide pellets using the powder-free process called Calcined Resin Microsphere Pelletization (CRMP). Details are given about oxide microsphere synthesis and particularly about loading operation and heat treatments. The fabrication of ceramic pellets is also described and discussed. Results showed that this process allows the preparation of either dense or porous pellets by mixing U3O8 and UO2-like microspheres before pressing and sintering.

  19. Fabrication of uranium dioxide ceramic pellets with controlled porosity from oxide microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Remy, E. [Radiochemistry and Processes Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Picart, S., E-mail: sebastien.picart@cea.fr [Radiochemistry and Processes Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Delahaye, T. [Fuel Cycle Technology Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Jobelin, I. [Radiochemistry and Processes Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Dugne, O. [Fuel Cycle Technology Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Bisel, I. [Radiochemistry and Processes Department, CEA, Nuclear Energy Division, F-30207 Bagnols-sur-Cèze (France); Blanchart, P. [Heterogeneous Materials Research Group, Centre Européen de la Céramique, F-87068 Limoges (France); Ayral, A. [Institut Européen des Membranes, UMR 5635 CNRS-ENSCM-UM2, University of Montpellier, F-34095 Montpellier cedex 5 (France)

    2014-05-01

    This study concerns the fabrication of uranium oxide pellets using the powder-free process called Calcined Resin Microsphere Pelletization (CRMP). Details are given about oxide microsphere synthesis and particularly about loading operation and heat treatments. The fabrication of ceramic pellets is also described and discussed. Results showed that this process allows the preparation of either dense or porous pellets by mixing U{sub 3}O{sub 8} and UO{sub 2}-like microspheres before pressing and sintering.

  20. Microspheres of poly(ε-caprolactone) loaded Holmium-165: morphology and thermal degradation behavior

    International Nuclear Information System (INIS)

    Geraldes, Adriana Napoleao; Miyamoto, Douglas Massao; Lira, Raphael Arivar de; Osso Junior, Joao Alberto; Nascimento, Nanci; Azevedo, Mariangela de Burgos M. de

    2011-01-01

    Polycaprolactone (PCL), being one of the most important biocompatible and biodegradable aliphatic polyester, provides many potential biomedical. The preparation of biodegradable materials, polymer-based microspheres, is being developed by our group and the goal is to prepare and label with Ho-165 different polymer-based microspheres. The use of radionuclide-loaded microspheres is a promising treatment of liver malignancies. PCL microspheres can be loaded with holmium acetylacetonate (HoAcAc). PCL and PCL/HoAcAc microspheres were prepared by an emulsion solvent extraction/evaporation technique. The PCL/ HoAcAc microspheres were irradiated in a nuclear reactor IEA-R1 at IPEN/CNEN-SP to radionuclide activation. Gamma irradiation was performed at 25 and 50 kGy doses. The microspheres were evaluated by differential scanning calorimetry analysis (DSC), thermogravimetric analysis (TG), Fourier transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and con focal laser scanning microscopy (CLSM). In the CLSM images were observed emission in 488 nm characteristic of holmium. The SEM surface image of PCL/HoAcAc microspheres showed more roughness than PCL microspheres. TG of PCL/HoAcAc microspheres showed a substantial weight loss above 200 degree C, indicating decomposition of HoAcAc. The residual weight indicates the presence of Ho 2 O 3 . Gamma irradiation at 25 and 50 kGy doses had no effect on the PCL/HoAcAc microspheres, which indicates that the chemical composition of the microspheres had not change. (author)

  1. Facile synthesis of monodisperse porous Co3O4 microspheres with superior ethanol sensing properties.

    Science.gov (United States)

    Sun, Chunwen; Rajasekhara, Shreyas; Chen, Yujin; Goodenough, John B

    2011-12-28

    A solvothermal method was developed to prepare on a large scale monodisperse porous β-Co(OH)(2) microspheres consisting of nanoplatelets. Co(3)O(4) microspheres with porous platelets were obtained via subsequent thermal decomposition. These Co(3)O(4) microspheres show much higher ethanol sensitivity and selectivity at a relatively low temperature (135 °C) compared with those of commercial Co(3)O(4) nanoparticles. This journal is © The Royal Society of Chemistry 2011

  2. Facile growth and composition-dependent photocatalytic activity of flowerlike BiOCl{sub 1−x}Br{sub x} hierarchical microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Qin; Guo, Yingna [School of Chemistry, Northeast Normal University, Changchun 130024 (China); Zhou, Dandan; Yang, Yuxin [School of Environment, Northeast Normal University, Changchun, 130117 (China); Guo, Yihang, E-mail: guoyh@nenu.edu.cn [School of Environment, Northeast Normal University, Changchun, 130117 (China)

    2016-12-30

    Highlights: • Flowerlike BiOCl{sub 1−x}Br{sub x} hierarchical microspheres were prepared by solvothermal route. • BiOCl{sub 1−x}Br{sub x} microspheres exhibited composition-dependent photocatalytic activity. • Band gap and potential of valence band dominated the photoactivity of BiOCl{sub 1−x}Br{sub x}. • BiOCl{sub 1−x}Br{sub x} microspheres can be reused at least four times without obvious activity loss. - Abstract: A group of nanosheet-assembled three-dimensional BiOCl{sub 1−x}Br{sub x} hierarchical microspheres (x = 0, 0.3, 0.4, 0.5, 0.7, 0.8 and 1.0) with layered tetragonal crystal phase were prepared by 2-methoxyethanol-assisted solvothermal route and using ionic liquids as both halogen sources and structure-directing agent. By the combination of the results including XRD, XPS and UV–vis/DR spectra, lattice substitution of halogen atoms each other and then formation of BiOCl{sub 1−x}Br{sub x} solid solution was evidenced. Additionally, the BiOCl{sub 1−x}Br{sub x} microspheres exhibited interesting composition-dependent band gaps. The simulated sunlight and visible-light photocatalytic properties including degradation, mineralization and reusability of the BiOCl{sub 1−x}Br{sub x} microspheres were evaluated by selecting p-nitrophenol (PNP) and tetrabromobisphenol-A (TBBPA) as the target pollutant compounds, finding that the balance between the suitable band gap and adequate potential of the valence band in BiOCl{sub 1−x}Br{sub x} crystals dominated their photocatalytic activity. Additionally, the BiOCl{sub 1−x}Br{sub x} microspheres with advantages such as enhanced photon utilization efficiency, larger BET surface area and favorable (110) exposed reactive surface gave the positive influence on their photocatalytic activity. Based on the results of photoelectrochemistry experiment and indirect chemical probe testing, direct {sup •} O{sub 2}{sup −} and h{sub VB}{sup +} photooxidation for the decomposition of PNP or TBBPA was

  3. Preparative process for hollow glass microsphere with wall thickness under 1 μm

    International Nuclear Information System (INIS)

    Du Shoude; Wei Sheng; Shi Tao

    1998-12-01

    The process for mass producing the high quality glass microspheres has been developed for ICF in China. The wall thickness of these microspheres is less than one micron. The effect of each zone temperature of drop furnace, flow rate of furnace air, solid concentration in the glass forming solution and concentration of the blowing agent on parameters of glass microspheres such as diameter and wall thickness are systematically studied. Glass microspheres with walls under 1 μm thick and which satisfy the exacting surface and symmetry specifications of targets for Shen-Guang-II directly driven experiments are now produced routinely

  4. Microsphere-assisted super-resolution imaging with enlarged numerical aperture by semi-immersion

    Science.gov (United States)

    Wang, Fengge; Yang, Songlin; Ma, Huifeng; Shen, Ping; Wei, Nan; Wang, Meng; Xia, Yang; Deng, Yun; Ye, Yong-Hong

    2018-01-01

    Microsphere-assisted imaging is an extraordinary simple technology that can obtain optical super-resolution under white-light illumination. Here, we introduce a method to improve the resolution of a microsphere lens by increasing its numerical aperture. In our proposed structure, BaTiO3 glass (BTG) microsphere lenses are semi-immersed in a S1805 layer with a refractive index of 1.65, and then, the semi-immersed microspheres are fully embedded in an elastomer with an index of 1.4. We experimentally demonstrate that this structure, in combination with a conventional optical microscope, can clearly resolve a two-dimensional 200-nm-diameter hexagonally close-packed (hcp) silica microsphere array. On the contrary, the widely used structure where BTG microsphere lenses are fully immersed in a liquid or elastomer cannot even resolve a 250-nm-diameter hcp silica microsphere array. The improvement in resolution through the proposed structure is due to an increase in the effective numerical aperture by semi-immersing BTG microsphere lenses in a high-refractive-index S1805 layer. Our results will inform on the design of microsphere-based high-resolution imaging systems.

  5. Facile preparation of multifunctional superparamagnetic PHBV microspheres containing SPIONs for biomedical applications

    Science.gov (United States)

    Li, Wei; Jan Zaloga; Ding, Yaping; Liu, Yufang; Janko, Christina; Pischetsrieder, Monika; Alexiou, Christoph; Boccaccini, Aldo R.

    2016-01-01

    The promising potential of magnetic polymer microspheres in various biomedical applications has been frequently reported. However, the surface hydrophilicity of superparamagnetic iron oxide nanoparticles (SPIONs) usually leads to poor or even failed encapsulation of SPIONs in hydrophobic polymer microspheres using the emulsion method. In this study, the stability of SPIONs in poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) solution was significantly increased after surface modification with lauric acid. As a result, magnetic PHBV microspheres with high encapsulation efficiencies (71.0–87.4%) were prepared using emulsion-solvent extraction/evaporation method. Magnetic resonance imaging (MRI) showed significant contrast for the magnetic PHBV microspheres. The toxicity of these magnetic PHBV microspheres towards human T-lymphoma suspension cells and adherent colon carcinoma HT-29 cells was investigated using flow cytometry, and they were shown to be non-toxic in a broad concentration range. A model drug, tetracycline hydrochloride, was used to demonstrate the drug delivery capability and to investigate the drug release behavior of the magnetic PHBV microspheres. The drug was successfully loaded into the microspheres using lauric acid-coated SPIONs as drug carrier, and was released from the microspheres in a diffusion controlled manner. The developed magnetic PHBV microspheres are promising candidates for biomedical applications such as targeted drug delivery and MRI. PMID:27005428

  6. COLOCASIA ESCULENTA CORMS MUCILAGE-ALGINATE MICROSPHERES OF OXCARBAZEPINE: DESIGN, OPTIMIZATION AND EVALUATION.

    Science.gov (United States)

    Ghumman, Shazia Akram; Bashir, Sajid; Ahmad, Jamshed; Hameed, Huma; Khan, Ikram Ullah

    2017-03-01

    The present investigation was undertaken with an objective of formulating sustained release microspheres of oxcarbazepine (OXC), an anti-epileptic drug, to overcome poor patient compliance and exposure to high doses associated with currently marketed OXC dosage forms. Ionic gelation technique was used to prepare OXC microspheres by using sodium alginate along with rate controlling polymer Colocasia esculenta mucilage (CEM) matrix as well coated form. The microspheres have been characterized by differential scanning calorimetry (DSC) for understanding thermal stability and Fourier transform infrared (FT-IR) spectroscopy to investigate the chemical interaction as well as to assess the structure of drug-loaded formulation. Surface morphology of the microspheres was investigated by scanning electron microscope (SEM). The size distribution of OXC microspheres as studied by optical microscopy was in the range of 394-575 pm. The microspheres exhibited encapsulating efficiency from 75 to 92%. The release of drug from the microspheres at pH 1.2 is negligible. Under neutral conditions, the microspheres were swell and release was attributed mainly to polymer relaxation. The release pattern from microspheres followed Korsmeyer-Peppas model and the value of n > 1 showed that drug released by anomalous (non-Fickian) diffusion. The data obtained thus suggest that a microparticulate system can be successfully designed by using CEM with alginate for sustained delivery of OXC.

  7. INVESTIGATION OF DRUG RELEASE FROM BIODEGRADABLE PLG MICROSPHERES: EXPERIMENT AND THEORY

    Energy Technology Data Exchange (ETDEWEB)

    ANDREWS, MALCOLM J. [Los Alamos National Laboratory; BERCHANE, NADER S. [Los Alamos National Laboratory; CARSON, KENNETH H. [Los Alamos National Laboratory; RICE-FICHT, ALLISON C. [Los Alamos National Laboratory

    2007-01-30

    Piroxicam containing PLG microspheres having different size distributions were fabricated, and in vitro release kinetics were determined for each preparation. Based on the experimental results, a suitable mathematical theory has been developed that incorporates the effect of microsphere size distribution and polymer degradation on drug release. We show from in vitro release experiments that microsphere size has a significant effect on drug release rate. The initial release rate decreased with an increase in microsphere size. In addition, the release profile changed from first order to concave-upward (sigmoidal) as the system size was increased. The mathematical model gave a good fit to the experimental release data.

  8. ZnO microspheres-reduced graphene oxide nanocomposite for photocatalytic degradation of methylene blue dye

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Jiaqian, E-mail: jiaqian.q@chula.ac.th [Metallurgy and Materials Science Research Institute, Chulalongkorn University, Bangkok 10330 (Thailand); Zhang, Xinyu, E-mail: xyzhang@ysu.edu.cn [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Yang, Chengwu; Cao, Meng; Ma, Mingzhen; Liu, Riping [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China)

    2017-01-15

    Highlights: • ZnO microspheres-rGO nanocomposites were prepared via a solution method. • ZnO microspheres anchored on the rGO sheets is observed using SEM and TEM. • The obtained nanocomposites exhibit good photocatalytic degradation of MB under UV light irradiation. - Abstract: In this work, ZnO microspheres-reduced graphene oxide (rGO) nanocomposites were synthesized via a simple solution method and used for the photodegradation of methylene blue (MB) dye from water under UV light. The SEM and TEM observations demonstrate that the microsphere morphologies of the ZnO microspheres-rGO nanocomposite is composed of ZnO microspheres anchored on rGO sheets, confirming the formation of ZnO microspheres-rGO composites. Raman spectra and X-ray photoelectron spectroscopy reveal that both of the reduction of GO tight contact between ZnO and rGO are achieved during the high temperature calcination process. During the photocatalytic test, in comparison with ZnO microspheres and P25 TiO2, the ZnO microspheres-rGO nanocomposite shows improved photodegradation of MB dye, because the rGO sheets could reduce the charge recombination in electron-transfer processes. According to the scavenger experiments, the possible MB degradation mechanism is contributed mainly to the generation of active species induced by the photogenerated holes (h{sup +}) and superoxide radicals (·O{sub 2}{sup −}).

  9. Method for selecting hollow microspheres for use in laser fusion targets

    Science.gov (United States)

    Farnum, Eugene H.; Fries, R. Jay; Havenhill, Jerry W.; Smith, Maurice Lee; Stoltz, Daniel L.

    1976-01-01

    Hollow microspheres having thin and very uniform wall thickness are useful as containers for the deuterium and tritium gas mixture used as a fuel in laser fusion targets. Hollow microspheres are commercially available; however, in commercial lots only a very small number meet the rigid requirements for use in laser fusion targets. Those meeting these requirements may be separated from the unsuitable ones by subjecting the commercial lot to size and density separations and then by subjecting those hollow microspheres thus separated to an external pressurization at which those which are aspherical or which have nonuniform walls are broken and separating the sound hollow microspheres from the broken ones.

  10. Effect of various polymers concentrations on physicochemical properties of floating microspheres.

    Science.gov (United States)

    Jagtap, Y M; Bhujbal, R K; Ranade, A N; Ranpise, N S

    2012-11-01

    Floating microspheres have emerged as a potential candidate for gastroretentive drug delivery system. For developing a desired intragastric floatation system employing these microspheres, it is necessary to select an appropriate balance between buoyancy and drug releasing rate. These properties mainly depend on the polymers used in the formulation of the microspheres. Hence it is necessory to study the effect of these polymer concentrations on the various physicochemical properties of the microspheres. Floating microspheres were prepared by emulsion solvent evaporation technique utilising different polymers such as ethyl cellulose, Eudragit(®) RS and Eudragit(®) RL by dissolving them in a mixture of dichloromethane and methanol. Release modifiers studied were hydroxypropyl methylcellulose K4M, hydroxypropyl methylcellulose E50 LV and Eudragit(®) EPO. Prepared microspheres were analysed for particle size, surface morphology, entrapment efficiency, buoyancy, differential scanning calorimetry and in-vitro drug release. Ethyl cellulose and Eudragit(®) EPO resulted microspheres with high percentage yield, excellent spherical shape but had very less buoyancies with a high cumulative drug release. Ethyl cellulose microspheres prepared using hydroxypropyl methylcellulose K4M showed more sustained drug release and high buoyancies than that of the microspheres formulated with the hydroxypropyl methylcellulose E50 LV. Amongst these hydroxypropyl methylcellulose E50 LV showed good balance between buoyancy and the drug release.

  11. Investigation of Expandable Polymeric Microspheres for Packaging Applications

    Science.gov (United States)

    2012-06-06

    printing inks , internally pressurized tennis balls, and foaming cable compounds. Microspheres were compounded into high density polyethylene...microspheres), printing  inks   (60‐80%), and tennis balls  and foaming cable filling compounds (over 99%) [2].  According to a literature search, polymer...Density  (g/cm³)  0.96  0.90  Oxygen  Permeability   (cc/m²)  1550‐3100  2325‐3100  Water Vapor  Permeability   (gm/m²)  4.65‐7.75  3.10‐7.75    2.1.2

  12. Evaluation of the degradation of clonidine-loaded PLGA microspheres.

    Science.gov (United States)

    Gaignaux, Amélie; Réeff, Jonathan; De Vriese, Carine; Goole, Jonathan; Amighi, Karim

    2013-01-01

    The release of an encapsulated drug is dependent on diffusion and/or degradation/erosion processes. This work aimed to better understand the degradation mechanism of clonidine-loaded microparticles. Gel permeation chromatography was used to evaluate the degradation of the polymer. The water-uptake and the weight loss were determined gravimetrically. The swelling behaviour and the morphological changes of the formulations were observed by microscopy. The glass transition temperature and the crystallinity were also determined by differential scanning calorimetry and X-ray diffraction, respectively. The pH of the medium and inside the microspheres was assessed. The microspheres captured a large amount of water, allowing a decrease in the molecular weight of the polymer. The pH of the medium decreased after release of the degradation products and the pH inside the microparticles remained constant due to the neutralization of these acidic products. Clonidine and buffers both had an action on the degradation.

  13. Study of neutron absorbing microspheres in research reactors - Neutronic analyse

    International Nuclear Information System (INIS)

    Gana Watkins, Ignacio A.; Prado, Miguel O.; Mazufri, Claudio; Tunon, Juan M

    2012-01-01

    Now-a-days, it is increasingly common for nuclear power plants, as well as research reactors, to be designed and built with an alternative safety system aside from control rods. The acids and/or salts in solution injection systems is most frequently used. However, these systems present several implementation and operation problems due to the physical and chemical properties of the used compounds. After analyzing these drawbacks, we developed a new alternative safety system that contains the absorbing element isolated from the aqueous medium. In this context, it's proposed the use of aluminum borosilicate microspheres. The current paper presents erosion wear experiments to determine under which conditions microspheres can be considered as a potential component of a secondary shut down system in a nuclear facility (author)

  14. Polyamic acid coating of microspheres by oriented thermal vapor deposition

    International Nuclear Information System (INIS)

    Huang Yong; Zhang Zhanwen; Liu Yiyang; Li Bo; Chen Shufen; Qi Xiaobo

    2011-01-01

    In this paper, a study on the oriented thermal vapor deposition device which is used for coating microspheres with polyamic acid (PAA) is developed. Influences of the processing of monomer material and the adjusting of heating process on the deposition rate are discussed. Two different monomers are poured into two evaporators and evaporated independently, the deposition rate and film thickness are measured via two film thickness measuring probes with the crystal vibration. Space position and symmetry of sample pan, two probes and the oriented tube tip are adjusted so that two monomers' deposition ratio approximates to stoichiometric ratio. High quality coating of PAA on poly-alpha-methylstyrene microsphere is acquired by intermittent piezoelectricity vibration or striking which accompanies rotating of the sample pan. (authors)

  15. Self-assembled mesoporous hierarchical-like In2S3 hollow microspheres composed of nanofibers and nanosheets and their photocatalytic activity.

    Science.gov (United States)

    Rengaraj, Selvaraj; Venkataraj, Selvaraj; Tai, Cheuk-wai; Kim, Younghun; Repo, Eveliina; Sillanpää, Mika

    2011-05-03

    Novel template-free hierarchical-like In(2)S(3) hollow microspheres were synthesized using thiosemicarbazide (NH(2)NHCSNH(2)) as both a sulfur source and a capping ligand in a ethanol/water system. In this study, we demonstrate that several process parameters, such as the reaction time and precursor ratio, strongly influence the morphology of the final product. The In(NO(3))(3)/thiosemicarbazide ratios were found to effectively play crucial roles in the morphologies of the hierarchical-like In(2)S(3) hollow microsphere nanostructure. With the ratios increasing from two to four, the In(2)S(3) crystals exhibited almost spherical morphologies. The synthesized products have been characterized by a variety of methods, including X-ray powder diffraction (XRD), Raman spectroscopy, field-emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), energy-dispersive X-ray (EDX) analysis, X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible diffused reflectance spectroscopy (UV-vis DRS). XRD analysis confirmed the tetragonal structure of the In(2)S(3) hollow microspheres. The products show complex hierarchical structures assembled from nanoscale building blocks. The morphology evolution can be realized on both outside (surface) and inside (hollow cavity) the microsphere. The surface area analysis showed that the porous In(2)S(3) possesses a specific surface area of 108 m(2)/g and uniform distribution of pore sizes corresponding to the size of pores resulting from the self-assembled structures with flakes. The optical properties of In(2)S(3) were also investigated by UV-vis DRS, which indicated that our In(2)S(3) microsphere samples possess a band gap of ∼1.96 eV. Furthermore, the photocatalytic activity studies revealed that the synthesized In(2)S(3) hollow microspheres exhibit an excellent photocatalytic performance in rapidly degrading aqueous methylene blue dye solution under visible light irradiation. These

  16. Magnetic poly(glycidyl methacrylate) microspheres for protein capture

    Czech Academy of Sciences Publication Activity Database

    Koubková, Jana; Müller, P.; Hlídková, Helena; Plichta, Zdeněk; Proks, Vladimír; Vojtěšek, B.; Horák, Daniel

    2014-01-01

    Roč. 31, č. 5 (2014), s. 482-491 ISSN 1871-6784 R&D Projects: GA ČR GCP207/12/J013; GA MŠk 7E12053 EU Projects: European Commission(XE) 246513 - NADINE Institutional support: RVO:61389013 Keywords : glycidyl methacrylate * microspheres * protein p53 Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.898, year: 2014

  17. The measurement of radioactive microspheres in biological samples

    International Nuclear Information System (INIS)

    Mernagh, J.R.; Spiers, E.W.; Adiseshiah, M.

    1976-01-01

    Measurements of the distribution of radioactive microspheres are used in investigations of regional coronary blood flow, but the size and shape of the heart varies for different test animals, and the organ is frequently divided into smaller pieces for studies of regional perfusion. Errors are introduced by variations in the distribution of the radioactive source and the amount of Compton scatter in different samples. A technique has therefore been developed to allow the counting of these tissue samples in their original form, and correction factors have been derived to inter-relate the various counting geometries thus encountered. Dogs were injected with microspheres labelled with 141 Ce, 51 Cr or 85 Sr. The tissue samples did not require remodelling to fit a standard container, and allowance was made for the inhomogeneous distribution in the blood samples. The activities in the centrifuged blood samples were correlated with those from the tissue samples by a calibration procedure involving comparisons of the counts from samples of microspheres embedded in sachets of gelatine, and similar samples mixed with blood and then centrifuged. The calibration data have indicated that 51 Cr behaves anomalously, and its use as a label for microspheres may introduce unwarranted errors. A plane cylindrical 10 x 20 cm NaI detector was used, and a 'worst case' correction of 20% was found to be necessary for geometry effects. The accuracy of this method of correlating different geometries was tested by remodelling the same tissue sample into different sizes and comparing the results, and the validity of the technique was supported by agreement of the final results with previously published data. (U.K.)

  18. In vitro Evaluation of Nateglinide-Loaded Microspheres Formulated ...

    African Journals Online (AJOL)

    urea receptors for its action with a short half life of 1.5 to 2 hrs. It is administered before meal so in order to prolong its effect, controlled release microspheres of nateglinide are .... vibration at 1714 cm-1 and N-H stretching appeared at 3298 cm-1 as shown in Figure 2. C=O stretching, C-O stretching and C-O-H stretching in ...

  19. Microsphere imaging with confocal microscopy and two photon microscopy

    International Nuclear Information System (INIS)

    Chun, Hyung Su; An, Kyung Won; Lee, Jai Hyung

    2002-01-01

    We have acquired images of polystyrene and fused-silica microsphere by using conventional optical microscopy, confocal microscopy and two-photon microscopy, and performed comparative analysis of these images. Different from conventional optical microscopy, confocal and two-photon microscopy had good optical sectioning capability. In addition, confocal microscopy and two-photon microscopy had better lateral resolution than conventional optical microscopy. These results are attributed to confocality and nonlinearity of confocal microscopy and two photon microscopy, respectively.

  20. Immunomagnetic sulfonated hypercrosslinked polystyrene microspheres for electrochemical detection of proteins

    Czech Academy of Sciences Publication Activity Database

    Šálek, Petr; Korecká, L.; Horák, Daniel; Petrovský, Eduard; Kovářová, Jana; Metelka, R.; Čadková, M.; Bílková, Z.

    2011-01-01

    Roč. 21, č. 38 (2011), s. 14783-14792 ISSN 0959-9428 R&D Projects: GA ČR GA203/09/0857; GA ČR GA203/09/1242 Institutional research plan: CEZ:AV0Z40500505; CEZ:AV0Z30120515 Keywords : styrene * divinylbenzene * microspheres Subject RIV: CD - Macromolecular Chemistry Impact factor: 5.968, year: 2011

  1. Porous spherical shells and microspheres by electrodispersion precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Harris, M.T.; Sisson, W.G.; Basaran, O.A.; Hayes, S.M.; Bobrowski, S.J.

    1994-12-31

    The ability to reproduce the synthesis of dense- and porous-microspheres and micron-sized spherical shells is very important in (a) the development of ceramics for structural, electronic, catalyst and thermal applications; and (b) the encapsulation of products for controlled-release of drugs, flavors and perfumes, and inks and dyes, and the protection of light-sensitive components and mechanical support of fragile materials. Larger metallic- and ceramic-spherical shells have been used in inertial confinement fusion (ICF) experiments and as catalyst supports. The current paper will focus on a recent technique that has been developed for synthesizing ceramic microspheres and micro-shells. Pulsed electric fields have been used to enhance the dispersion of aqueous metal (Zr and Al) salt solutions from a nozzle and into a nonconducting liquid continuous phase that is immiscible with the aqueous phase. The diameter of the resulting microdroplets ranged in size from approximately 0.1 to 10 {mu}m. Precipitation of hydrous metal oxides occurred as ammonia, which was dissolved in varying amounts in the continuous phase, diffused into the aqueous microdroplets. Spherical shells were formed at higher ammonia concentrations and microspheres were produced at lower ammonia concentrations. Upon drying, dimples appeared in the particles that were synthesized at higher ammonia concentrations. The latter result accords with the well known fact that under certain conditions spherical shells collapse when a fluid is extracted from the core of the particle. No dimples were observed in the microspheres that were produced at lower ammonia concentrations. Analog X-ray dot maps for aluminum and zirconium were done to determine the spatial distribution of each metal in the particles.

  2. Porous spherical shells and microspheres by electrodispersion precipitation

    International Nuclear Information System (INIS)

    Harris, M.T.; Sisson, W.G.; Basaran, O.A.; Hayes, S.M.; Bobrowski, S.J.

    1994-01-01

    The ability to reproduce the synthesis of dense- and porous-microspheres and micron-sized spherical shells is very important in (a) the development of ceramics for structural, electronic, catalyst and thermal applications; and (b) the encapsulation of products for controlled-release of drugs, flavors and perfumes, and inks and dyes, and the protection of light-sensitive components and mechanical support of fragile materials. Larger metallic- and ceramic-spherical shells have been used in inertial confinement fusion (ICF) experiments and as catalyst supports. The current paper will focus on a recent technique that has been developed for synthesizing ceramic microspheres and micro-shells. Pulsed electric fields have been used to enhance the dispersion of aqueous metal (Zr and Al) salt solutions from a nozzle and into a nonconducting liquid continuous phase that is immiscible with the aqueous phase. The diameter of the resulting microdroplets ranged in size from approximately 0.1 to 10 μm. Precipitation of hydrous metal oxides occurred as ammonia, which was dissolved in varying amounts in the continuous phase, diffused into the aqueous microdroplets. Spherical shells were formed at higher ammonia concentrations and microspheres were produced at lower ammonia concentrations. Upon drying, dimples appeared in the particles that were synthesized at higher ammonia concentrations. The latter result accords with the well known fact that under certain conditions spherical shells collapse when a fluid is extracted from the core of the particle. No dimples were observed in the microspheres that were produced at lower ammonia concentrations. Analog X-ray dot maps for aluminum and zirconium were done to determine the spatial distribution of each metal in the particles

  3. Multiscale and luminescent, hollow microspheres for gas phase thermometry

    OpenAIRE

    Bischoff, Lothar; Stephan, Michael; Birkel, Christina S.; Litterscheid, Christian F.; Dreizler, Andreas; Albert, Barbara

    2018-01-01

    Recently developed laser-based measurement techniques are used to image the temperatures and velocities in gas flows. They require new phosphor materials with an unprecedented combination of properties. A novel synthesis procedure is described here; it results in hierarchically structured, hollow microspheres of Eu3+-doped Y2O3, with unusual particle sizes and very good characteristics compared to full particles. Solution-based precipitation on polymer microballoons produces very stable and l...

  4. Fabrication of polystyrene hollow microspheres as laser fusion ...

    Indian Academy of Sciences (India)

    Fabrication of polystyrene hollow microspheres γwater air falls from 72 mN m 1 to 30 mN m 1), and hence the work required to increase the surface tension on emulsification (γ∆A) or the free energy ∆Gem needed to disperse a liquid of volumeV with drop of radius R (∆Gem =γ •3V/R). Pressure gradient required to.

  5. Power output and efficiency of beta-emitting microspheres

    International Nuclear Information System (INIS)

    Cheneler, David; Ward, Michael

    2015-01-01

    Current standard methods to calculate the dose of radiation emitted during medical applications by beta-minus emitting microspheres rely on an over-simplistic formalism. This formalism is a function of the average activity of the radioisotope used and the physiological dimensions of the patient only. It neglects the variation in energy of the emitted beta particle due to self-attenuation, or self-absorption, effects related to the finite size of the sphere. Here it is assumed the sphere is comprised of a pure radioisotope with beta particles being emitted isotropically throughout the material. The full initial possible kinetic energy distribution of a beta particle is taken into account as well as the energy losses due to scattering by other atoms in the microsphere and bremsstrahlung radiation. By combining Longmire’s theory of the mean forward range of charged particles and the Rayleigh distribution to take into account the statistical nature of scattering and energy straggling, the linear attenuation, or self-absorption, coefficient for beta-emitting radioisotopes has been deduced. By analogy with gamma radiation transport in spheres, this result was used to calculate the rate of energy emitted by a beta-emitting microsphere and its efficiency. Comparisons to standard point dose kernel formulations generated using Monte Carlo data show the efficacy of the proposed method. Yttrium-90 is used as a specific example throughout, as a medically significant radioisotope, frequently used in radiation therapy for treating cancer. - Highlights: • Range-energy relationship for the beta particles in yttrium-90 is calculated. • Formalism for the semi-analytical calculation of self-absorption coefficients. • Energy-dependent self-absorption coefficient calculated for yttrium-90. • Flux rate of beta particles from a self-attenuating radioactive sphere is shown. • The efficiency of beta particle emitting radioactive microspheres is calculated

  6. Hypercrosslinked polystyrene microspheres by suspension and dispersion polymerization

    Czech Academy of Sciences Publication Activity Database

    Šálek, Petr; Horák, Daniel

    -, 064 (2011), s. 1-12 ISSN 1618-7229 R&D Projects: GA ČR GA203/09/0857; GA ČR GAP503/10/0664; GA MŠk 2B06053 Institutional research plan: CEZ:AV0Z40500505 Keywords : polystyrene * microspheres * hypercrosslinked Subject RIV: EE - Microbiology, Virology Impact factor: 0.515, year: 2011 http://www.e-polymers.org/journal/papers/dhorak_230611.pdf

  7. Carefully calibrated microsphere embolization of tumors and AVMs

    International Nuclear Information System (INIS)

    Laurent, A.; Wassef, M.; Beaujeux, R.; Hodes, J.E.; Gobin, P.Y.; Schenker, C.; Bouchez, B.; Brette, M.D.; Aymard, A.; Cophignon, J.; Merland, J.J.

    1990-01-01

    This paper evaluates the efficacy of a new type of uniformly calibrated microsphere for embolization of various pathologies. Fourteen tumors (five intracranial, eight extracranial, one spine), and seven facial arteriovenous malformations (AVMs) (nose, lip, and scalp) were embolized preoperatively. Angiographic, surgical devascularization, and histologic findings were correlated with the spheres' size. In the second part of the study, spinal cord (n = 22) and intracerbral (n = 14) AVM, Weber-Osler-Rendu disease (n = 2), and epistaxis (n = 1) embolization was angiographically evaluated

  8. Multiplex detection of plant pathogens using a microsphere immunoassay technology.

    Directory of Open Access Journals (Sweden)

    Ratthaphol Charlermroj

    Full Text Available Plant pathogens are a serious problem for seed export, plant disease control and plant quarantine. Rapid and accurate screening tests are urgently required to protect and prevent plant diseases spreading worldwide. A novel multiplex detection method was developed based on microsphere immunoassays to simultaneously detect four important plant pathogens: a fruit blotch bacterium Acidovorax avenae subsp. citrulli (Aac, chilli vein-banding mottle virus (CVbMV, potyvirus, watermelon silver mottle virus (WSMoV, tospovirus serogroup IV and melon yellow spot virus (MYSV, tospovirus. An antibody for each plant pathogen was linked on a fluorescence-coded magnetic microsphere set which was used to capture corresponding pathogen. The presence of pathogens was detected by R-phycoerythrin (RPE-labeled antibodies specific to the pathogens. The assay conditions were optimized by identifying appropriate antibody pairs, blocking buffer, concentration of RPE-labeled antibodies and assay time. Once conditions were optimized, the assay was able to detect all four plant pathogens precisely and accurately with substantially higher sensitivity than enzyme-linked immunosorbent assay (ELISA when spiked in buffer and in healthy watermelon leaf extract. The assay time of the microsphere immunoassay (1 hour was much shorter than that of ELISA (4 hours. This system was also shown to be capable of detecting the pathogens in naturally infected plant samples and is a major advancement in plant pathogen detection.

  9. Multiplex detection of plant pathogens using a microsphere immunoassay technology.

    Science.gov (United States)

    Charlermroj, Ratthaphol; Himananto, Orawan; Seepiban, Channarong; Kumpoosiri, Mallika; Warin, Nuchnard; Oplatowska, Michalina; Gajanandana, Oraprapai; Grant, Irene R; Karoonuthaisiri, Nitsara; Elliott, Christopher T

    2013-01-01

    Plant pathogens are a serious problem for seed export, plant disease control and plant quarantine. Rapid and accurate screening tests are urgently required to protect and prevent plant diseases spreading worldwide. A novel multiplex detection method was developed based on microsphere immunoassays to simultaneously detect four important plant pathogens: a fruit blotch bacterium Acidovorax avenae subsp. citrulli (Aac), chilli vein-banding mottle virus (CVbMV, potyvirus), watermelon silver mottle virus (WSMoV, tospovirus serogroup IV) and melon yellow spot virus (MYSV, tospovirus). An antibody for each plant pathogen was linked on a fluorescence-coded magnetic microsphere set which was used to capture corresponding pathogen. The presence of pathogens was detected by R-phycoerythrin (RPE)-labeled antibodies specific to the pathogens. The assay conditions were optimized by identifying appropriate antibody pairs, blocking buffer, concentration of RPE-labeled antibodies and assay time. Once conditions were optimized, the assay was able to detect all four plant pathogens precisely and accurately with substantially higher sensitivity than enzyme-linked immunosorbent assay (ELISA) when spiked in buffer and in healthy watermelon leaf extract. The assay time of the microsphere immunoassay (1 hour) was much shorter than that of ELISA (4 hours). This system was also shown to be capable of detecting the pathogens in naturally infected plant samples and is a major advancement in plant pathogen detection.

  10. PLGA microspheres containing bee venom proteins for preventive immunotherapy.

    Science.gov (United States)

    Trindade, Reginaldo A; Kiyohara, Pedro K; de Araujo, Pedro S; Bueno da Costa, Maria H

    2012-02-14

    Bee venom (BV) allergy is potentially dangerous for allergic individuals because a single bee sting may induce an anaphylactic reaction, eventually leading to death. Currently, venom immunotherapy (VIT) is the only treatment with long-lasting effect for this kind of allergy and its efficiency has been recognized worldwide. This therapy consists of subcutaneous injections of gradually increasing doses of the allergen. This causes patient lack of compliance due to a long time of treatment with a total of 30-80 injections administered over years. In this article we deal with the characterization of different MS-PLGA formulations containing BV proteins for VIT. The PLGA microspheres containing BV represent a strategy to replace the multiple injections, because they can control the solute release. Physical and biochemical methods were used to analyze and characterize their preparation. Microspheres with encapsulation efficiencies of 49-75% were obtained with a BV triphasic release profile. Among them, the MS-PLGA 34kDa-COOH showed to be best for VIT because they presented a low initial burst (20%) and a slow BV release during lag phase. Furthermore, few conformational changes were observed in the released BV. Above all, the BV remained immunologically recognizable, which means that they could continuously stimulate the immune system. Those microspheres containing BV could replace sequential injections of traditional VIT with the remarkable advantage of reduced number of injections. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Power output and efficiency of beta-emitting microspheres

    Science.gov (United States)

    Cheneler, David; Ward, Michael

    2015-01-01

    Current standard methods to calculate the dose of radiation emitted during medical applications by beta-minus emitting microspheres rely on an over-simplistic formalism. This formalism is a function of the average activity of the radioisotope used and the physiological dimensions of the patient only. It neglects the variation in energy of the emitted beta particle due to self-attenuation, or self-absorption, effects related to the finite size of the sphere. Here it is assumed the sphere is comprised of a pure radioisotope with beta particles being emitted isotropically throughout the material. The full initial possible kinetic energy distribution of a beta particle is taken into account as well as the energy losses due to scattering by other atoms in the microsphere and bremsstrahlung radiation. By combining Longmire's theory of the mean forward range of charged particles and the Rayleigh distribution to take into account the statistical nature of scattering and energy straggling, the linear attenuation, or self-absorption, coefficient for beta-emitting radioisotopes has been deduced. By analogy with gamma radiation transport in spheres, this result was used to calculate the rate of energy emitted by a beta-emitting microsphere and its efficiency. Comparisons to standard point dose kernel formulations generated using Monte Carlo data show the efficacy of the proposed method. Yttrium-90 is used as a specific example throughout, as a medically significant radioisotope, frequently used in radiation therapy for treating cancer.

  12. Unique Urchin-like Ca2Ge7O16 Hierarchical Hollow Microspheres as Anode Material for the Lithium Ion Battery

    Science.gov (United States)

    Li, Dan; Feng, Chuanqi; Liu, Hua Kun; Guo, Zaiping

    2015-06-01

    Germanium is an outstanding anode material in terms of electrochemical performance, especially rate capability, but its developments are hindered by its high price because it is rare in the crust of earth, and its huge volume variation during the lithium insertion and extraction. Introducing other cheaper elements into the germanium-based material is an efficient way to dilute the high price, but normally sacrifice its electrochemical performance. By the combination of nanostructure design and cheap element (calcium) introduction, urchin-like Ca2Ge7O16 hierarchical hollow microspheres have been successfully developed in order to reduce the price and maintain the good electrochemical properties of germanium-based material. The electrochemical test results in different electrolytes show that ethylene carbonate/dimethyl carbonate/diethyl carbonate (3/4/3 by volume) with 5 wt% fluoroethylene carbonate additive is the most suitable solvent for the electrolyte. From the electrochemical evaluation, the as-synthesized Ca2Ge7O16 hollow microspheres exhibit high reversible specific capacity of up to 804.6 mA h g-1 at a current density of 100 mA g-1 after 100 cycles and remarkable rate capability of 341.3 mA h g-1 at a current density of 4 A g-1. The growth mechanism is proposed based on our experimental results on the growth process.

  13. Mobilization of microspheres from a fractured soil during intermittent infiltration events

    Science.gov (United States)

    Mohanty, Sanjay; Bulicek, Mark; Metge, David W.; Harvey, Ronald W.; Ryan, Joseph N.; Boehm, Alexandria B.

    2015-01-01

    Pathogens or biocolloids mobilized in the vadose zone may consequently contaminate groundwater. We found that microspheres were mobilized from a fractured soil during intermittent rainfall and the mobilization was greater when the microsphere size was larger and when the soil had greater water permeability.The vadose zone filters pathogenic microbes from infiltrating water and consequently protects the groundwater from possible contamination. In some cases, however, the deposited microbes may be mobilized during rainfall and migrate into the groundwater. We examined the mobilization of microspheres, surrogates for microbes, in an intact core of a fractured soil by intermittent simulated rainfall. Fluorescent polystyrene microspheres of two sizes (0.5 and 1.8 mm) and Br− were first applied to the core to deposit the microspheres, and then the core was subjected to three intermittent infiltration events to mobilize the deposited microspheres. Collecting effluent samples through a 19-port sampler at the base of the core, we found that water flowed through only five ports, and the flow rates varied among the ports by a factor of 12. These results suggest that flow paths leading to the ports had different permeabilities, partly due to macropores. Although 40 to 69% of injected microspheres were retained in the core during their application, 12 to 30% of the retained microspheres were mobilized during three intermittent infiltration events. The extent of microsphere mobilization was greater in flow paths with greater permeability, which indicates that macropores could enhance colloid mobilization during intermittent infiltration events. In all ports, the 1.8-mm microspheres were mobilized to a greater extent than the 0.5-mm microspheres, suggesting that larger colloids are more likely to mobilize. These results are useful in assessing the potential of pathogen mobilization and colloid-facilitated transport of contaminants in the subsurface under natural infiltration

  14. Development of in vitro-in vivo correlation of parenteral naltrexone loaded polymeric microspheres.

    Science.gov (United States)

    Andhariya, Janki V; Shen, Jie; Choi, Stephanie; Wang, Yan; Zou, Yuan; Burgess, Diane J

    2017-06-10

    Establishment of in vitro-in vivo correlations (IVIVCs) for parenteral polymeric microspheres has been very challenging, due to their complex multiphase release characteristics (which is affected by the nature of the drug) as well as the lack of compendial in vitro release testing methods. Previously, a Level A correlation has been established and validated for polymeric microspheres containing risperidone (a practically water insoluble small molecule drug). The objectives of the present study were: 1) to investigate whether a Level A IVIVC can be established for polymeric microspheres containing another small molecule drug with different solubility profiles compared to risperidone; and 2) to determine whether release characteristic differences (bi-phasic vs tri-phasic) between microspheres can affect the development and predictability of IVIVCs. Naltrexone was chosen as the model drug. Three compositionally equivalent formulations of naltrexone microspheres with different release characteristics were prepared using different manufacturing processes. The critical physicochemical properties (such as drug loading, particle size, porosity, and morphology) as well as the in vitro release characteristics of the prepared naltrexone microspheres and the reference-listed drug (Vivitrol®) were determined. The pharmacokinetics of the naltrexone microspheres were investigated using a rabbit model. The obtained pharmacokinetic profiles were deconvoluted using the Loo-Riegelman method, and compared with the in vitro release profiles of the naltrexone microspheres obtained using USP apparatus 4. Level A IVIVCs were established and validated for predictability. The results demonstrated that the developed USP 4 method was capable of detecting manufacturing process related performance changes, and most importantly, predicting the in vivo performance of naltrexone microspheres in the investigated animal model. A critical difference between naltrexone and risperidone loaded

  15. Preparation of magnetic polylactic acid microspheres and investigation of its releasing property for loading curcumin

    Energy Technology Data Exchange (ETDEWEB)

    Li Fengxia [Heilongjiang Key Laboratory of Molecular Design and Preparation of Flame Retarded Materials, College of Science, Northeast Forestry University, Harbin 150040 (China); Li Xiaoli, E-mail: lixiaoli0903@163.com [Heilongjiang Key Laboratory of Molecular Design and Preparation of Flame Retarded Materials, College of Science, Northeast Forestry University, Harbin 150040 (China); Li Bin, E-mail: libinzh62@163.com [Heilongjiang Key Laboratory of Molecular Design and Preparation of Flame Retarded Materials, College of Science, Northeast Forestry University, Harbin 150040 (China)

    2011-11-15

    In order to obtain a targeting drug carrier system, magnetic polylactic acid (PLA) microspheres loading curcumin were synthesized by the classical oil-in-water emulsion solvent-evaporation method. In the Fourier transform infrared spectra of microspheres, the present functional groups of PLA were all kept invariably. The morphology and size distribution of magnetic microspheres were observed with scanning electron microscopy and dynamic light scattering, respectively. The results showed that the microspheres were regularly spherical and the surface was smooth with a diameter of 0.55-0.75 {mu}m. Magnetic Fe{sub 3}O{sub 4} was loaded in PLA microspheres and the content of magnetic particles was 12 wt% through thermogravimetric analysis. The magnetic property of prepared microspheres was measured by vibrating sample magnetometer. The results showed that the magnetic microspheres exhibited typical superparamagnetic behavior and the saturated magnetization was 14.38 emu/g. Through analysis of differential scanning calorimetry, the curcumin was in an amorphous state in the magnetic microspheres. The drug loading, encapsulation efficiency and releasing properties of curcumin in vitro were also investigated by ultraviolet-visible spectrum analysis. The results showed that the drug loading and encapsulation efficiency were 8.0% and 24.2%, respectively. And curcumin was obviously slowly released because the cumulative release percentage of magnetic microspheres in the phosphate buffer (pH=7.4) solution was only 49.01% in 72 h, and the basic release of curcumin finished in 120 h. - Highlights: > We prepare magnetic polylactic acid microspheres loading curcumin. > The classical oil-in-water emulsion solvent-evaporation method is used. > The magnetic microspheres are regularly spherical with a diameter of 0.55-0.75 {mu}m. > They show a certain sustained release effect on in vitro drug releasing.

  16. Preparation of magnetic polylactic acid microspheres and investigation of its releasing property for loading curcumin

    International Nuclear Information System (INIS)

    Li Fengxia; Li Xiaoli; Li Bin

    2011-01-01

    In order to obtain a targeting drug carrier system, magnetic polylactic acid (PLA) microspheres loading curcumin were synthesized by the classical oil-in-water emulsion solvent-evaporation method. In the Fourier transform infrared spectra of microspheres, the present functional groups of PLA were all kept invariably. The morphology and size distribution of magnetic microspheres were observed with scanning electron microscopy and dynamic light scattering, respectively. The results showed that the microspheres were regularly spherical and the surface was smooth with a diameter of 0.55-0.75 μm. Magnetic Fe 3 O 4 was loaded in PLA microspheres and the content of magnetic particles was 12 wt% through thermogravimetric analysis. The magnetic property of prepared microspheres was measured by vibrating sample magnetometer. The results showed that the magnetic microspheres exhibited typical superparamagnetic behavior and the saturated magnetization was 14.38 emu/g. Through analysis of differential scanning calorimetry, the curcumin was in an amorphous state in the magnetic microspheres. The drug loading, encapsulation efficiency and releasing properties of curcumin in vitro were also investigated by ultraviolet-visible spectrum analysis. The results showed that the drug loading and encapsulation efficiency were 8.0% and 24.2%, respectively. And curcumin was obviously slowly released because the cumulative release percentage of magnetic microspheres in the phosphate buffer (pH=7.4) solution was only 49.01% in 72 h, and the basic release of curcumin finished in 120 h. - Highlights: → We prepare magnetic polylactic acid microspheres loading curcumin. → The classical oil-in-water emulsion solvent-evaporation method is used. → The magnetic microspheres are regularly spherical with a diameter of 0.55-0.75 μm. → They show a certain sustained release effect on in vitro drug releasing.

  17. Design of sustained-release nitrendipine microspheres having solid dispersion structure by quasi-emulsion solvent diffusion method

    DEFF Research Database (Denmark)

    Cui, Fude; Yang, Mingshi; Jiang, Yanyan

    2003-01-01

    that the particle size of microspheres was determined mainly by the agitation speed. The dissolution rate of nitrendipine from microspheres was enhanced significantly with increasing the amount of dispersing agents, and sustained by adding retarding agents. The release rate of microspheres could be controlled...

  18. The influence of increased cross-linker chain length in thermosensitive microspheres on potential sun-protection activity

    OpenAIRE

    Musiał, Witold; Kokol, Vanja; Vončina, Bojana

    2012-01-01

    The sun protection should involve substances with protecting activity against both UVB and UVA radiation. In this research the evaluation of thermosensitive microspheres as potential molecules for sunscreen formulations was approached, using modified Boots star rating system. The microspheres, thermosensitive N-isopropylacrylamide derivatives, have potential protecting activity against UV radiation. The MX and DX microspheres, with ethylene glycol dimethacrylate and diethylene glycol dimethac...

  19. Synthesis of Y2O2S:Eu3+, Mg2+, Ti4+ hollow microspheres via homogeneous precipitation route

    Directory of Open Access Journals (Sweden)

    Peng-Fei Ai, Ying-Liang Liu, Li-Yuan Xiao, Hou-Jin Wang and Jian-Xin Meng

    2010-01-01

    Full Text Available A phosphorescent material in the form of Y2O2S:Eu3+, Mg2+, Ti4+ hollow microspheres was prepared by homogeneous precipitation using monodispersed carbon spheres as hard templates. Y2O3:Eu3+ hollow microspheres were first synthesized to serve as the precursor. Y2O2S:Eu3+, Mg2+, Ti4+ powders were obtained by calcinating the precursor in a CS2 atmosphere. The crystal structure, morphology and optical properties of the composites were characterized. X-ray diffraction measurements confirmed the purity of the Y2O2S phase. Electron microscopy observations revealed that the Y2O2S:Eu3+, Mg2+, Ti4+ particles inherited the hollow spherical shape from the precursor after being calcined in a CS2 atmosphere and that they had a diameter of 350–450 nm and a wall thickness of about 50–80 nm. After ultraviolet radiation at 265 or 325 nm for 5 min, the particles emitted strong red long-lifetime phosphorescence originating from Eu3+ ions. This phosphorescence is associated with the trapping of charge carriers by Ti4+ and Mg2+ ions.

  20. The impacts of replacing air bubbles with microspheres for the clarification of algae from low cell-density culture.

    Science.gov (United States)

    Ometto, Francesco; Pozza, Carlo; Whitton, Rachel; Smyth, Beatrice; Gonzalez Torres, Andrea; Henderson, Rita K; Jarvis, Peter; Jefferson, Bruce; Villa, Raffaella

    2014-04-15

    Dissolved Air Flotation (DAF) is a well-known coagulation-flotation system applied at large scale for microalgae harvesting. Compared to conventional harvesting technologies DAF allows high cell recovery at lower energy demand. By replacing microbubbles with microspheres, the innovative Ballasted Dissolved Air Flotation (BDAF) technique has been reported to achieve the same algae cell removal efficiency, while saving up to 80% of the energy required for the conventional DAF unit. Using three different algae cultures (Scenedesmus obliquus, Chlorella vulgaris and Arthrospira maxima), the present work investigated the practical, economic and environmental advantages of the BDAF system compared to the DAF system. 99% cells separation was achieved with both systems, nevertheless, the BDAF technology allowed up to 95% coagulant reduction depending on the algae species and the pH conditions adopted. In terms of floc structure and strength, the inclusion of microspheres in the algae floc generated a looser aggregate, showing a more compact structure within single cell alga, than large and filamentous cells. Overall, BDAF appeared to be a more reliable and sustainable harvesting system than DAF, as it allowed equal cells recovery reducing energy inputs, coagulant demand and carbon emissions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Synthesis of core-shell TiO2@g-C3N4 hollow microspheres for efficient photocatalytic degradation of rhodamine B under visible light

    Science.gov (United States)

    Ma, Lina; Wang, Guohong; Jiang, Chuanjia; Bao, Helin; Xu, Qingchuan

    2018-02-01

    Core-shell composites with titanium dioxide (TiO2) hollow microsphere as the core and graphitic carbon nitride (g-C3N4) as the shell were fabricated via a two-step self-assembly procedure with the assistance of ultrasonic dispersion. The as-prepared composite samples with different g-C3N4 contents (0-20%) were thoroughly characterized and the photocatalytic activity was evaluated by the photocatalytic degradation of Rhodamine B (RhB) in aqueous solution under visible light. A g-C3N4 layer of approximately 80 nm was successfully coated on the surface of TiO2 hollow microspheres with a diameter of 1-3 μm, forming a heterostructure with close interfacial contact. The TiO2@g-C3N4 composite exhibited significantly enhanced photocatalytic activity as compared with pure TiO2 hollow microspheres. At an optimum weight ratio of g-C3N4 to TiO2 (15 wt.%), the photocatalytic activity of the composite sample was almost 3 times higher than that of reference TiO2 hollow microspheres. Moreover, the results of recycling test indicated that the TiO2@g-C3N4 composite had excellent stability. A possible photocatalytic reaction mechanism of TiO2@g-C3N4 composite was proposed, in which superoxide radical anions played the major role in the oxidation of RhB, and the separation of photogenerated charge carriers across the heterostructure interface inhibited electron-hole recombination, thus enhancing the photocatalytic activity.

  2. Effect of particle size on drug loading and release kinetics of gefitinib-loaded PLGA microspheres

    NARCIS (Netherlands)

    Chen, Weiluan; Palazzo, Amelia; Hennink, Wim E.; Kok, Robbert J.

    2017-01-01

    Polymeric microspheres have gained widespread application as drug eluting depots. Typically, drug-loaded polymeric microspheres are prepared by oil-in-water emulsification which yields a product with a broad size distribution. The aim of the present study was to investigate the properties of

  3. Kinetics of piroxicam release from low-methylated pectin/zein hydrogel microspheres

    Science.gov (United States)

    The kinetics of a model drug (piroxicam) release from pectin/zein hydrogel microspheres was studied under conditions simulating the gastrointestinal tract. It is established that the rate-limiting step in the release mechanism is drug diffusion out of the microspheres rather than its dissolution. ...

  4. Laser surface micro-/nano-structuring by a simple transportable micro-sphere lens array

    NARCIS (Netherlands)

    Sedao, X.; Derrien, T.J.Y.; Romer, G.W.R.B.E.; Pathiraj, B.; Huis in 't Veld, A.J.

    2012-01-01

    A micro-sphere array optic was employed for laser surface micro-structuring. This array optic consists of a hexagonally close-packed monolayer of silica micro-spheres. It was organized through a self-assembly process and held together on a glass support, without using any adhesives. The array

  5. The deformation of hydrogel microspheres at the air/water interface.

    Science.gov (United States)

    Minato, Haruka; Murai, Masaki; Watanabe, Takumi; Matsui, Shusuke; Takizawa, Masaya; Kureha, Takuma; Suzuki, Daisuke

    2018-01-23

    The deformation of soft hydrogel microspheres (microgels) adsorbed at the air/water interface was investigated for the first time using large poly(N-isopropyl acrylamide)-based microgels synthesized by a modified aqueous precipitation polymerization method. The deformation of the micron-sized soft microspheres could be visualized clearly and analyzed quantitatively at the air/water interface.

  6. Bovine serum albumin adsorption to iron-oxide coated sands can change microsphere deposition mechanisms.

    Science.gov (United States)

    Flynn, Raymond M; Yang, Xinyao; Hofmann, Thilo; von der Kammer, Frank

    2012-03-06

    Particulate colloids often occur together with proteins in sewage-impacted water. Using Bovine Serum Albumin (BSA) as a surrogate for protein in sewage, column experiments investigating the capacity of iron-oxide coated sands to remove latex microspheres from water revealed that microsphere attenuation mechanisms depended on antecedent BSA coverage. Dual pulse experiment (DPE) results suggested that where all BSA was adsorbed, subsequent multiple pore volume microsphere breakthrough curves reflected progressively reduced colloid deposition rates with increasing adsorbed BSA content. Modeling colloid responses suggested adsorption of 1 μg BSA generated the same response as blockage by between 7.1 × 10(8) and 2.3 × 10(9) deposited microspheres. By contrast, microsphere responses in DPEs where BSA coverage of the deposition sites approached/reached saturation revealed the coated sand maintained a finite capacity to attenuate microspheres, even when incapable of further BSA adsorption. Subsequent microsphere breakthrough curves demonstrated the matrix's colloid attenuation capacity progressively increased with continued microsphere deposition. Experimental findings suggested BSA adsorption on the sand surface approaching/reaching saturation generated attractive deposition sites for colloids, which became progressively more attractive with further colloid deposition (filter ripening). Results demonstrate that adsorption of a single type of protein may either enhance or inhibit colloid mobility in saturated porous media.

  7. Non-traditional whispering gallery modes inside microspheres visualized with Fourier analysis

    NARCIS (Netherlands)

    Chang, Lantian; Timmermans, Frank; Otto, Cees

    2017-01-01

    Non-traditional whispering gallery modes are studied in a glass microsphere. Geometrical ray tracing is used to explain and calculate these modes. Thermal emission and Raman scattering are used as an internal light source to excite these modes inside the glass microsphere. The thermal and Raman

  8. Depletion-Induced Encapsulation by Dumbbell-Shaped Patchy Colloids Stabilize Microspheres against Aggregation

    NARCIS (Netherlands)

    Wolters, Joost R.; Verweij, Joanne E.; Avvisati, Guido; Dijkstra, Marjolein; Kegel, Willem K.

    2017-01-01

    In this paper, we demonstrate the stabilization of polystyrene microspheres by encapsulating them with dumbbell-shaped colloids with a sticky and a nonsticky lobe. Upon adding a depletant, an effective short ranged attraction is induced between the microspheres and the smaller, smooth lobes of the

  9. Formulation and characterization of microspheres loaded with imatinib for sustained delivery

    NARCIS (Netherlands)

    Ramazani, F.; Chen, W.; van Nostrum, C.F.; Storm, Gerrit; Kiessling, F.; Lammers, Twan Gerardus Gertudis Maria; Hennink, Wim E.; Kok, R.J.

    2015-01-01

    The aim of this study was the development of imatinib-loaded poly(d,l-lactide-co-glycolide) (PLGA) microspheres with high loading efficiency which can afford continuous release of imatinib over a prolonged period of time. Imatinib mesylate loaded PLGA microspheres with a size of 6–20 μm were

  10. Formulation and characterization of microspheres loaded with imatinib for sustained delivery

    NARCIS (Netherlands)

    Ramazani, F.; Chen, W.; Van Nostrum, C. F.; Storm, G.; Kiessling, F.; Lammers, T.; Hennink, W. E.; Kok, R. J.

    2015-01-01

    The aim of this study was the development of imatinib-loaded poly(d,l-lactide-co-glycolide) (PLGA) microspheres with high loading efficiency which can afford continuous release of imatinib over a prolonged period of time. Imatinib mesylate loaded PLGA microspheres with a size of 6-20 μm were

  11. Release of proteins via ion exchange from albumin-heparin microspheres

    NARCIS (Netherlands)

    Kwon, Glen S.; Bae, You Han; Cremers, H.F.M.; Cremers, Harry; Feijen, Jan; Kim, Sung Wan

    1992-01-01

    Albumin-heparin and albumin microspheres were prepared as ion exchange gels for the controlled release of positively charged polypeptides and proteins. The adsorption isotherms of chicken egg and human lysozyme, as model proteins, on microspheres were obtained. An adsorption isotherm of chicken egg

  12. Mineralization, biodegradation, and drug release behavior of gelatin/apatite composite microspheres for bone regeneration.

    NARCIS (Netherlands)

    Leeuwenburgh, S.C.G.; Jo, J.; Wang, H.; Yamamoto, M.; Jansen, J.A.; Tabata, Y.

    2010-01-01

    Gelatin microspheres are well-known for their capacity to release growth factors in a controlled manner, but gelatin microspheres do not calcify in the absence of so-called bioactive substances that induce deposition of calcium phosphate (CaP) bone mineral. This study has investigated if CaP

  13. Preparation and Comparative Bioavailability Studies of Indomethacin-Loaded Cetyl Alcohol Microspheres

    Directory of Open Access Journals (Sweden)

    N. Vishal Gupta

    2013-01-01

    Full Text Available The purpose of the present study was to compare the in vitro release and to find out whether the bioavailability of a 75 mg indomethacin capsule (Microcid SR was equivalent to optimized formulation (indomethacin-loaded cetyl alcohol microspheres. Indomethacin-loaded cetyl alcohol microspheres were prepared by meltable emulsified cooling-induced technique. Surface morphology of microspheres has been evaluated using scanning electron microscopy. A single dose, randomized, complete cross over study of IM microspheres was carried out on 10 healthy male and female Albino sheep’s under fasting conditions. The plasma was separated and the concentrations of the drug were determined by HPLC-UV method. Plasma indomethacin concentrations and other pharmacokinetic parameters obtained were statistically analyzed. The SEM images revealed the spherical shape of fat microspheres, and more than 98.0% of the isolated microspheres were in the size range 12–32 μm. DSC, FTIR spectroscopy and stability studies indicated that the drug after encapsulation with fat microspheres was stable and compatible. Both formulations were found to be bioequivalent as evidenced by in vivo studies. Based on this study, it can be concluded that cetyl alcohol microspheres and Microcid SR capsule are bioequivalent in terms of the rate and extent of absorption.

  14. Preparation of porous LaFeO{sub 3} microspheres and their gas-sensing property

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Hongxia; Xue, Cheng; Song, Peng, E-mail: mse_songp@ujn.edu.cn; Li, Jia; Wang, Qi

    2015-05-15

    Graphical abstract: - Highlights: • Porous LaFeO{sub 3} microspheres have been successfully synthesized by a convenient and effective hydrothermal method. • The synthesis method has the advantages of controllable fabrication, simple equipment and no additional template. • The mechanism for the formation of porous LaFeO{sub 3} microspheres has been explained in accordance with the Ostwald ripening process. • The as-prepared porous LaFeO{sub 3} microspheres exhibited potential applications in monitoring acetone gas. - Abstract: Porous micro-/nanostructures are of great interest in many current and emerging areas of technology. In this paper, porous microspheres composed of LaFeO{sub 3} nanoparticles were prepared by a convenient and effective method. The obtained microspheres have been structurally characterized by X-ray diffraction analysis (XRD), which confirms the single crystalline orthorhombic structure. By using scanning electron microscopy (SEM), it can be seen that porous LaFeO{sub 3} microspheres with rough surface were assembled from a large amount of interconnected nanoparticles. And transmission electron microscopy (TEM) image has also confirmed their porous feature. A subsequent plausible formation mechanism of porous LaFeO{sub 3} microspheres has been explained in accordance with the Ostwald ripening process. Moreover, gas sensing investigation showed that the sensor based on porous LaFeO{sub 3} microspheres exhibited potential applications in monitoring acetone gas due to their unique morphology and porous structure.

  15. The physical and chemical stability of suspensions of sustained-release diclofenac microspheres.

    Science.gov (United States)

    Lewis, L; Boni, R L; Adeyeye, C M

    1998-01-01

    The major challenge in liquid sustained-release oral suspensions is to minimize drug diffusion into the suspending medium and to retain the original properties of the microparticles during storage. Diclofenac wax microspheres prepared by the hydrophobic congealable disperse phase method were formulated as a sustained release suspension and stored at three different temperatures (25, 37 and 45 degrees C) for 3 months, to evaluate the physical and chemical stability of the suspended microspheres. Suspensions of microspheres stored at ambient temperatures were both physically and chemically stable, but at higher temperatures, up to 45 degrees C, there was a decrease in drug release due to scaling and melting on the microsphere surface as observed by scanning electron microscopy. However, on prolonged storage, up to 90 days, especially at 45 degrees C, temperature became a dominant factor causing an increase in drug release. The suspension of diclofenac microspheres was chemically stable for 3 months, while the plain drug suspension exhibited slight degradation.

  16. Photochemical welding of silica microspheres to silicone rubber by ArF excimer laser

    Science.gov (United States)

    Okoshi, Masayuki; Iyono, Minako; Inoue, Narumi; Yamashita, Tsugito

    2009-09-01

    Transparent fused silica (SiO 2) microspheres 2.5 μm in diameter were photochemically welded to transparent, flexible silicone rubber ([SiO(CH 3) 2] n) substrate by 193 nm ArF excimer laser induced photochemical modification of silicone into silicon oxide. Single layer of silica microspheres was easily formed on an adhesive silicone rubber before laser irradiation after dropping of silica microspheres dispersed in ethanol and subsequent tape peeling. The welding rate, the percentage of welded microspheres tested by ultrasonic cleaning with ethanol, was examined by varying the single pulse fluence and irradiation time of ArF excimer laser. The welding layer underneath microsphere, silicon oxide, was also found to emit white light of strong intensity under UV light illumination.

  17. Behaviour of (Th, U)O2 microspheres under compression tests and pelletization

    International Nuclear Information System (INIS)

    Ferreira, R.A.N.

    1982-12-01

    The interrelation between the behaviour of isolated microspheres in compression tests and the microstructure of sintered pellets obtained with these microspheres, was investigated. Various batches of (Th, 5 w/o U)O 2 microspheres were produced applying the so-called gel process. The production parameters were diversified both as to the composition and to the heat treatments. The resulting products underwent compression tests in an universal tension and compression machine as single microspheres and, as bulk material, were compacted and sintered. The results of the compression tests revealed the existence of two distinct classes of fragmentation behaviour. Each of these classes causes a distinct behaviour during the pelletization, too, resulting in fuel pellets with quite different microstructures. It was evidenced that there is a relationship between these differences in the microstructure and the behaviour of the single microspheres in the compression test. (Author) [pt

  18. Synthesis of cubic ZnS microspheres exhibiting broad visible emission for bioimaging applications.

    Science.gov (United States)

    Sajan, P; Jayasree, R S; Agouram, S; Bushiri, M Junaid

    2016-03-01

    Biocompatible ZnS microspheres with an average diameter of 3.85 µm were grown by solvo-hydrothermal (S-H) method using water-acetonitrile-ethylenediamine (EDA) solution combination. ZnS microspheres were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Fourier transform (FT)-Raman spectroscopy and Fourier transform infrared spectroscopy (FTIR) techniques. The broad photoluminescence (PL) emissions from 380-580 nm that were seen from the ZnS microspheres attributed to the increase in carrier concentration, as understood from the observed intense Raman band at 257 cm(-1). Cytotoxicity and haemocompatibility investigations of these ZnS microspheres revealed its biocompatibility. ZnS microspheres, along with biological cell lines, were giving visible light emission and could be used for bioimaging applications. Copyright © 2015 John Wiley & Sons, Ltd.

  19. Plasmon-modulated light scattering from gold nanocrystal-decorated hollow mesoporous silica microspheres.

    Science.gov (United States)

    Xiao, Manda; Chen, Huanjun; Ming, Tian; Shao, Lei; Wang, Jianfang

    2010-11-23

    Localized surface plasmon resonances of noble metal nanocrystals are powerful in enhancing a variety of linear and nonlinear optical signals and photorelated processes. Here we demonstrate the plasmonic enhancement of the light scattering from hollow mesoporous silica microspheres by attaching a dense layer of gold nanocrystals onto the outer surface of the microspheres. The attachment of gold nanocrystals induces both the shift and intensity increase in the resonant scattering peaks of the microspheres. The spectral region of the resonant scattering enhancement can be controlled by using gold nanocrystals with different plasmon resonance wavelengths. The spectral region of the enhancement is independent of the microsphere diameter. The scattering enhancement factor ranges from 20 to 130, depending on the plasmonic properties and surface coverage of the attached gold nanocrystals. The systematic evolution of the scattering spectra of the individual microspheres is also revealed by chemically etching away the attached gold nanocrystals gradually.

  20. Formulation and evalution of montelukast sodium - chitosan based spray dried microspheres for pulmonary drug delivery

    Directory of Open Access Journals (Sweden)

    Rushi Panchal

    2012-01-01

    Full Text Available The objective of present work was to prepare microspheres of montelukast sodium using a natural polymer- chitosan by spray drying method by using glutaraldehyde as a cross linking agent. The microspheres were characterized for size, shape, dissolution, swelling and mucoadhesion. It was observed that, all microspheres were spherical in shape with narrow size distribution. Microspheres had mean particle size of 7-12 μm, with % encapsulation efficiency of 78-86%. The % yield was 32-49% and drug load was 48-53%. With the increase in proportion of chitosan in formulation mucoadhesive strength was increase and also increased in particle size of microspheres. As the drug:polymer ratio increase drug loading was increase and % encapsulation efficiency was also increase.

  1. Preparation of poly(styrene-glucidylmethacrylate)/Fe 3O 4 composite microspheres with high magnetite contents

    Science.gov (United States)

    Zhang, Jing; Yu, Demei; Chen, Wei; Xie, Yunchuan; Wan, Weitao; Liang, Honglu; Min, Chao

    2009-03-01

    Magnetic polymer composite microspheres with high magnetite contents were prepared by dispersion polymerization of styrene (St) and glucidylmethacrylate (GMA), in which Fe 3O 4 nanoparticles were co-stabilized by oleic acid and silane surfactants. The microstructure of the composite microspheres was characterized by Fourier transform infrared (FTIR) spectrometry, X-ray diffraction (XRD) and transmission electron microscopy (TEM). Results demonstrated the presence of a hybrid morphology with organic polymer-encapsulated inorganic particles. Subsequently, thermogravimetric analysis (TGA) and vibrating sample magnetometry (VSM) were used to evaluate the magnetite content of the microspheres. It was found that an accordant magnetite content of about 70 wt%, could be obtained for the magnetic polymer microspheres, a value significantly higher than those reported thus far. The possible mechanism for the formation of the microspheres was proposed.

  2. Synthesis of V2O5 microspheres by spray pyrolysis as cathode material for supercapacitors

    Science.gov (United States)

    Yin, Zhendong; Xu, Jie; Ge, Yali; Jiang, Qiaoya; Zhang, Yaling; Yang, Yawei; Sun, Yuping; Hou, Siyu; Shang, Yuanyuan; Zhang, Yingjiu

    2018-03-01

    Vanadium oxide (V2O5) microspheres have attracted considerable attention in the energy field due to their unique properties such as high stability and electrochemical activity. Here, massive V2O5 microspheres with smooth surface, hollow cavity and uniform particle sizes (0.4–1.5 μm), were synthesized by a facile spray pyrolysis process. Post-treatment at predefined temperatures effectively turned the microsphere shell into stacked nanorods with widths of 100 nm and lengths of 500 nm when processed at 500 °C for 3 h under nitrogen atmosphere, with enhanced crystallinity. When applied as cathode materials for supercapacitors, the post-treated V2O5 microspheres at 500 °C exhibited improved specific capacitance and longer discharge time. This is an effective method to manufacture massive V2O5 microspheres with tailored structure and potential applications in high-performance energy storage materials.

  3. Carboxyl-Functionalized Polymeric Microspheres Prepared by One-Stage Photoinitiated RAFT Dispersion Polymerization

    Directory of Open Access Journals (Sweden)

    Jianbo Tan

    2017-12-01

    Full Text Available Herein, we report a photoinitiated reversible addition-fragmentation chain transfer (RAFT dispersion copolymerization of methyl methacrylate (MMA and methyl methacrylic (MAA for the preparation of highly monodisperse carboxyl-functionalized polymeric microspheres. High rates of polymerization were observed, with more than 90% particle yields being achieved within 3 h of UV irradiation. Effects of reaction parameters (e.g., MAA concentration, RAFT agent concentration, photoinitiator concentration, and solvent composition were studied in detail, and highly monodisperse polymeric microspheres were obtained in most cases. Finally, silver (Ag composite microspheres were prepared by in situ reduction of AgNO3 using the carboxyl-functionalized polymeric microspheres as the template. The obtained Ag composite microspheres were able to catalyze the reduction of methylene blue (MB with NaBH4 as a reductant.

  4. Nasal administration of heparin-loaded microspheres based on poly(lactic acid).

    Science.gov (United States)

    Yildiz, Ayca; Okyar, Alper; Baktir, Gül; Araman, Ahmet; Ozsoy, Yildiz

    2005-01-01

    In this study, heparin-loaded microspheres having smooth surface and small particle size were designed in order to provide the absorption of heparin through nasal mucosa. For this purpose, microspheres at different polymer/drug ratios (1:10, 1:2.5 and 1:1) and at different concentrations of polyvinyl alcohol, emulsifying agent (1.5% and 2.5% w/v) were prepared by solvent evaporation method with poly(lactic acid). The microspheres were for evaluated shape and surface properties, particle size, production yield, encapsulation efficiency and in vitro drug release. Based on the in vitro data, selected microspheres were applied by nasal route to Wistar albino rats. According to in vivo studies, heparin-loaded microspheres may be used by nasal route as an alternative to parenteral route.

  5. Floating microspheres of valacyclovir HCl: Formulation, optimization, characterization, in vitro and in vivo floatability studies

    Directory of Open Access Journals (Sweden)

    Nilamgiri Goswami

    2012-01-01

    Full Text Available Floating microspheres are multiple unit Gastroretentive drug delivery systems. Valacyclovir hydrochloride (VCH is L-valyl ester prodrug of acyclovir. VCH degrades in intestinal fluid. The objective was to develop floating microspheres of VCH to localise the drug at upper part of GIT, for improved absorption. Floating microspheres were prepared by W/O emulsification solvent evaporation method using Ethylcellulose (EC as polymer. Particle size and % EE were 550.021±0.241 μm, 79.88±2.236% respectively. in vitro and in vivo floatability studies confirmed floating behaviour of microspheres. VCH loaded floating microspheres can be a suitable alternative to the conventional formulation, by localizing the drug at upper GIT.

  6. Pilot trial of Y-90 glass microspheres in the treatment of primary hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Houle, S.; Yip, T.C.K.; Shepherd, F.A.; Rotstein, L.E.; Theis, B.; Cawthorn, R.; Barnes, K.

    1987-01-01

    A pilot trial is currently under way at our institution to determine the potential of new Y-90 glass microspheres (Theraspheres, Theragenics Corp., Atlanta) for the treatment of primary hepatocellular carcinoma. The Y-90 microspheres are injected through a percutaneous hepatic artery catheter positioned angiographically. The injection is facilitated by a new delivery system. Prior to the injection of the Y-90 microspheres, the presence of shunting is assessed by injecting Tc-99m human albumin microspheres (HAM) via the hepatic artery catheter. Bremsstrahlung scans done after injection demonstrate the distribution the Y-90 microspheres within the liver and the lack of extrahepatic activity. In the first group of patients treated, no significant toxicity was demonstrated for absorbed doses between 5,000 and 10,000 rad to the liver, and up to 20,000 rad to the tumor itself

  7. Effects of whispering gallery mode in microsphere super-resolution imaging

    Science.gov (United States)

    Zhou, Song; Deng, Yongbo; Zhou, Wenchao; Yu, Muxin; Urbach, H. P.; Wu, Yihui

    2017-09-01

    Whispering Gallery modes have been presented in microscopic glass spheres or toruses with many applications. In this paper, the possible approaches to enhance the imaging resolution by Whispering Gallery modes are discussed, including evanescent waves coupling, transformed and illustration by Whispering Gallery modes. It shows that the high-order scattering modes play the dominant role in the reconstructed virtual image when the Whispering Gallery modes exist. Furthermore, we find that the high image resolution of electric dipoles can be achieved, when the out-of-phase components exist from the illustration of Whispering Gallery modes. Those results of our simulation could contribute to the knowledge of microsphere-assisted super-resolution imaging and its potential applications.

  8. Polyaniline Coated Core-Shell Typed Stimuli-Responsive Microspheres and Their Electrorheology

    Directory of Open Access Journals (Sweden)

    Yu Zhen Dong

    2018-03-01

    Full Text Available Functional core-shell-structured particles have attracted considerable attention recently. This paper reviews the synthetic methods and morphologies of various electro-stimuli responsive polyaniline (PANI-coated core-shell-type microspheres, including PANI-coated Fe3O4, SiO2, Fe2O3, TiO2, poly(methyl methacrylate, poly(glycidyl methacrylate, and polystyrene along with their electrorheological (ER characteristics when prepared by dispersing these particles in an insulating medium. In addition to the various rheological characteristics and their analysis, such as shear stress and yield stress of their ER fluids, this paper summarizes some of the mechanisms proposed for ER fluids to further understand the responses of ER fluids to an externally applied electric field.

  9. Microspheres with an ultra high holmium content for brachytherapy of malignancies

    Energy Technology Data Exchange (ETDEWEB)

    Lira, Raphael A.; Myamoto, Douglas M.; Souza, Jaime R.; Nascimento, Nanci; Azevedo, Mariangela de Burgos M. de [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Biotecnologia; Osso Junior, Joao A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Radiofarmacia; Martinelli, Jose R. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Ciencias e Tecnologia de Materiais

    2011-07-01

    The overall objective of this work is to develop biodegradable microspheres intended for internal radiation therapy which provides an improved treatment for hepatic carcinomas. The most studied brachytherapy system employing microspheres made of holmium-biopolymer system is composed by poly(L-lactic acid) (PLLA) and holmium acetylacetonate (HoAcAc). The importance of the holmium high content in the microspheres can be interpreted as follow from a therapeutic standpoint, to achieve an effective use of microspheres loaded with HoAcAc, a high content of holmium is required to yield enough radioactivity with a relatively low amount of microspheres.The usual amounts of holmium that are incorporated in the microspheres composed by poly(L-lactic acid) and HoAcAc are 17.0 {+-} 0.5% (w/w) of holmium, which corresponds to a loading of about 50% of HoAcAc. Different approaches have been investigated to increase that value. One updated approach towards this direction is the production of microspheres with ultrahigh holmium as matrix using HoAcAc crystals as the sole starting material without the use of biopolymer. Likewise, in the search of microspheres with increased holmium content , it has been demonstrated that by changing the HoAcAc crystal structure by its recrystallization from crystal phase to the amorphous there is lost of acetylacetonate and water molecules causing the increasing of the holmium content. Microspheres were prepared by solvent evaporation, using holmium acetylacetonate (HoAcAc) crystals as the sole ingredient. Microspheres were characterized by using light and scanning electron microscopy, infrared and Raman spectroscopy, differential scanning calorimetry, X-rays diffraction, and confocal laser scanning microscopy. (author)

  10. [Preparation of citrulline microspheres by spray drying technique for colonic targeting].

    Science.gov (United States)

    Bahri, S; Zerrouk, N; Lassoued, M-A; Tsapis, N; Chaumeil, J-C; Sfar, S

    2014-03-01

    Citrulline is an amino acid that becomes essential in situations of intestinal insufficiency such as short bowel syndrome. It is therefore interesting to provide the patients with dosage forms for routing citrulline to the colon. The aim of this work is to formulate microspheres of citrulline for colonic targeting by the technique of spray drying. Eudragit(®) FS 30D was selected as polymer to encapsulate citrulline using the spray drying technique. Citrulline and Eudragit(®) FS 30D were dissolved in water and ethanol, respectively. The aqueous and the ethanolic solutions were then mixed in 1:2 (v/v) ratio. Microspheres were obtained by nebulizing the citrulline-Eudragit(®) FS 30D solution using a Mini spray dryer equipped with a 0.7mm nozzle. The microspheres have been formulated using citrulline and Eudragit(®) FS 30D. The size distribution of microspheres was determined by light diffraction. The morphology of the microspheres was studied by electron microscopy. Manufacturing yields, encapsulation rate and dissolution profiles were also studied. The microspheres obtained had a spherical shape with a smooth surface and a homogeneous size except for the microspheres containing the highest concentration of polymer (90 %). The formulation showed that the size and morphology of the microspheres are influenced by the polymer concentration. Manufacturing yields were about 51 % but encapsulation rate were always very high (above 90 %). The in vitro dissolution study showed that the use of the Eudragit(®) FS 30D under these conditions is not appropriate to change the dissolution profile of the citrulline. This technique has led to the formulation of microspheres with good physical properties in terms of morphology and size. The compression of the microspheres should help to control citrulline release for colonic targeting. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  11. Microspheres with an ultra high holmium content for brachytherapy of malignancies

    International Nuclear Information System (INIS)

    Lira, Raphael A.; Myamoto, Douglas M.; Souza, Jaime R.; Nascimento, Nanci; Azevedo, Mariangela de Burgos M. de; Osso Junior, Joao A.; Martinelli, Jose R.

    2011-01-01

    The overall objective of this work is to develop biodegradable microspheres intended for internal radiation therapy which provides an improved treatment for hepatic carcinomas. The most studied brachytherapy system employing microspheres made of holmium-biopolymer system is composed by poly(L-lactic acid) (PLLA) and holmium acetylacetonate (HoAcAc). The importance of the holmium high content in the microspheres can be interpreted as follow from a therapeutic standpoint, to achieve an effective use of microspheres loaded with HoAcAc, a high content of holmium is required to yield enough radioactivity with a relatively low amount of microspheres.The usual amounts of holmium that are incorporated in the microspheres composed by poly(L-lactic acid) and HoAcAc are 17.0 ± 0.5% (w/w) of holmium, which corresponds to a loading of about 50% of HoAcAc. Different approaches have been investigated to increase that value. One updated approach towards this direction is the production of microspheres with ultrahigh holmium as matrix using HoAcAc crystals as the sole starting material without the use of biopolymer. Likewise, in the search of microspheres with increased holmium content , it has been demonstrated that by changing the HoAcAc crystal structure by its recrystallization from crystal phase to the amorphous there is lost of acetylacetonate and water molecules causing the increasing of the holmium content. Microspheres were prepared by solvent evaporation, using holmium acetylacetonate (HoAcAc) crystals as the sole ingredient. Microspheres were characterized by using light and scanning electron microscopy, infrared and Raman spectroscopy, differential scanning calorimetry, X-rays diffraction, and confocal laser scanning microscopy. (author)

  12. [Construction and evaluation of the tissue engineered nerve of bFGF-PLGA sustained release microspheres].

    Science.gov (United States)

    Wang, Guanglin; Lin, Wei; Gao, Weiqiang; Xiao, Yuhua; Dong, Changchao

    2008-12-01

    To study the outcomes of nerve defect repair with the tissue engineered nerve, which is composed of the complex of SCs, 30% ECM gel, bFGF-PLGA sustained release microspheres, PLGA microfilaments and permeable poly (D, L-lactic acid) (PDLLA) catheters. SCs were cultured and purified from the sciatic nerves of 1-day-old neonatal SD rats. The 1st passage cells were compounded with bFGF-PLGA sustained release microspheres and ECM gel, and then were injected into permeable PDLLA catheters with PLGA microfilaments inside. In this way, the tissue engineered nerve was constructed. Sixty SD rats were included. The model of 15-mm sciatic nerve defects was made, and then the rats were randomly divided into 5 groups, with 12 rats in each. In group A, autograft was adopted. In group B, the blank PDLLA catheters with PBS inside were used. In group C, PDLLA catheters, with PLGA microfilaments and 30% ECM gel inside, were used. In group D, PDLLA catheters, with PLGA microfilaments, SCs and 30% ECM gel inside, were used. In group E, the tissue engineered nerve was applied. After the operation, observation was made for general conditions of the rats. The sciatic function index (SFI) analysis was performed at 12, 16, 20 and 24 weeks after the operation, respectively. Electrophysiological detection and histological observation were performed at 12 and 24 weeks after the operation, respectively. All rats survived to the end of the experiment. At 12 and 16 weeks after the operation, group E was significantly different from group B in SFI (P fibers in group E were significantly differents from those in groups A, B and C (P fibers in group E were smaller than those in group A (P fibers in group E was significantly different from those in groups A, B, C (P fibers in group E were bigger than those in groups B and C (P < 0.05). The tissue engineered nerve with the complex of SCs, ECM gel, bFGF-PLGA sustained release microspheres, PLGA microfilaments and permeable PDLLA catheters promote

  13. Inverse opal spheres based on polyionic liquids as functional microspheres with tunable optical properties and molecular recognition capabilities.

    Science.gov (United States)

    Cui, Jiecheng; Zhu, Wei; Gao, Ning; Li, Jian; Yang, Haowei; Jiang, Yin; Seidel, Philipp; Ravoo, Bart Jan; Li, Guangtao

    2014-04-07

    Based on the combination of the unique features of both polyionic liquids and spherical colloidal crystals, a new class of inverse opaline spheres with a series of distinct properties was fabricated. It was found that such photonic spheres could not only be used as stimuli-responsive photonic microgels, but also serve as multifunctional microspheres that mimic the main characteristics of conventional molecules, including intrinsic optical properties, specific molecular recognition, reactivity and derivatization, and anisotropy. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. ZnO@C (core@shell) microspheres derived from spent coffee grounds as applicable non-precious electrode material for DMFCs.

    Science.gov (United States)

    Ghouri, Zafar Khan; Al-Meer, Saeed; Barakat, Nasser A M; Kim, Hak Yong

    2017-05-11

    Although numerous reports have introduced non precious electrocatalysts for methanol oxidation, most of those studies did not consider the corresponding high onset potential which restricts utilization in real fuel cells. In this study, an -90 mV [vs. Ag/AgCl] onset potential non-precious electrocatalyst is introduced as an applicable anode material for the direct methanol fuel cells. Moreover, the proposed material was prepared from a cheap and abundantly existing resource; the spent coffee grounds. Typically, the spent coffee grounds were facilely converted to core@shell (ZnO@C) microspheres through a two-step approach, involving chemical activation and a subsequent calcination at temperature of 700 °C. Activation of the carbon derived from the spent coffee grounds was performed with ZnCl 2 which acts as pore-forming agent as well as a precursor for the ZnO. The structure and morphology were characterized by (XRD), (SEM), and (TEM) analyses while the electrochemical characterizations was evaluated by cyclic voltammetry (CV) technique. Besides the comparatively very low onset potential, the introduced microspheres exhibited relatively high current density; 17 mA/cm 2 . Overall, based on the advantages of the green source of carbon and the good electrocatalytic activity, the spent coffee grounds-derived carbon can be considered a promise anode material for the DMFCs.

  15. Organic-Carbon Sequestration in Soil/Sediment of the Mississippi River Deltaic Plain - Data; Landscape Distribution, Storage, and Inventory; Accumulation Rates; and Recent Loss, Including a Post-Katrina Preliminary Analysis (Chapter B)

    Science.gov (United States)

    Markewich, Helaine W.; Buell, Gary R.; Britsch, Louis D.; McGeehin, John P.; Robbins, John A.; Wrenn, John H.; Dillon, Douglas L.; Fries, Terry L.; Morehead, Nancy R.

    2007-01-01

    Soil/sediment of the Mississippi River deltaic plain (MRDP) in southeastern Louisiana is rich in organic carbon (OC). The MRDP contains about 2 percent of all OC in the surface meter of soil/sediment in the Mississippi River Basin (MRB). Environments within the MRDP differ in soil/sediment organic carbon (SOC) accumulation rate, storage, and inventory. The focus of this study was twofold: (1) develop a database for OC and bulk density for MRDP soil/sediment; and (2) estimate SOC storage, inventory, and accumulation rates for the dominant environments (brackish, intermediate, and fresh marsh; natural levee; distributary; backswamp; and swamp) in the MRDP. Comparative studies were conducted to determine which field and laboratory methods result in the most accurate and reproducible bulk-density values for each marsh environment. Sampling methods included push-core, vibracore, peat borer, and Hargis1 sampler. Bulk-density data for cores taken by the 'short push-core method' proved to be more internally consistent than data for samples collected by other methods. Laboratory methods to estimate OC concentration and inorganic-constituent concentration included mass spectrometry, coulometry, and loss-on-ignition. For the sampled MRDP environments, these methods were comparable. SOC storage was calculated for each core with adequate OC and bulk-density data. SOC inventory was calculated using core-specific data from this study and available published and unpublished pedon data linked to SSURGO2 map units. Sample age was estimated using isotopic cesium (137Cs), lead (210Pb), and carbon (14C), elemental Pb, palynomorphs, other stratigraphic markers, and written history. SOC accumulation rates were estimated for each core with adequate age data. Cesium-137 profiles for marsh soil/sediment are the least ambiguous. Levee and distributary 137Cs profiles show the effects of intermittent allochthonous input and/or sediment resuspension. Cesium-137 and 210Pb data gave the most

  16. Treatment options for unresectable HCC with a focus on SIRT with Yttrium-90 resin microspheres.

    Science.gov (United States)

    Wang, Eric A; Stein, Jeff P; Bellavia, Ross J; Broadwell, Scott R

    2017-11-01

    Hepatocellular carcinoma (HCC), the predominant form of primary liver cancer, is the second leading cause of cancer-related deaths across the globe. Only a small percentage of HCC patients (~20%-30%) are diagnosed at an early stage when first-line treatment options may be effective. The majority of HCC patients (>70%) are diagnosed with unresectable disease and given a poor overall prognosis. Current treatment guidelines recommend locoregional therapy with transarterial chemoembolisation (TACE) and systemic therapy with sorafenib as first-line treatment for patients with intermediate and advanced stage HCC. However, multiple factors including contraindications, technical considerations and treatment-related toxicities pose significant challenges in achieving favourable treatment outcomes, underscoring the need for a paradigm shift in managing these patients. In 2002, yttrium-90 (Y-90) resin microspheres was approved by the U.S. Food and Drug Administration (FDA) for the treatment of unresectable metastatic colorectal cancer to the liver with adjuvant floxuridine chemotherapy. However, thousands of patients with unresectable HCC have also been treated with resin Y-90. For over two decades, several small-scale prospective trials and retrospective studies have investigated and reported on the efficacy of locoregional selective internal radiation therapy (SIRT) with Y-90 microspheres in treating unresectable HCC. Although it is currently a treatment option for intermediate-stage HCC patients, mainstream clinical application of resin Y-90 has been largely limited because of the lack of sufficient clinical data from a randomised controlled trial. This could change with the imminent announcement of results from the phase 3 Sorafenib vs Radioembolization in Advanced Hepatocellular carcinoma (SARAH) trial. To provide the foundation and context for interpreting results from the SARAH trial, this article provides an overview of treatment modalities and current challenges in

  17. Sintering kinetics of U3O8 microspheres

    International Nuclear Information System (INIS)

    Godoy, A.L.E.

    1987-01-01

    Shrinkage and grain growth kinetics data are presented for microspheres produced from gels. The diametral variations may be described with an accuracy of the order of 8% by means of modified Gompertz equations. Using finite differences analysis it was shown that those equations correspond to deviations (average 3%) relative to the experimental values smaller than those obtained using simple exponential models. Relevant microstructural aspects are attested by optical and electron ceramography. Densities of the order of 98% of the theoretical value are reached in times and temperatures substantially smaller than those corresponding to ceramics formed from powder. (Author) [pt

  18. Method and means for producing solid evacuated microspheres of hydrogen

    Science.gov (United States)

    Turnbull, Robert J.; Foster, Christopher A.; Hendricks, Charles D.

    1976-01-01

    A method is provided for producing solid, evacuated microspheres comprised of hydrogen. The spheres are produced by forming a jet of liquid hydrogen and exciting mechanical waves on the jet of appropriate frequency so that the jet breaks up into drops with a bubble formed in each drop by cavitation. The drops are exposed to a pressure less than the vapor pressure of the liquid hydrogen so that the bubble which is formed within each drop expands. The drops which contain bubbles are exposed to an environment having a pressure just below the triple point of liquid hydrogen and they thereby freeze giving solid, evacuated spheres of hydrogen.

  19. PtNi nanoparticles embedded in porous silica microspheres as ...

    Indian Academy of Sciences (India)

    pension of SiO2 microspheres. H2PtCl6·6H2O aqueous solution (0.03352 mol/L, 0.08 mL) and Ni(NO3)2·6H2O. (0.9 mg) (with initial mass ratio of Pt:Ni=3:1) were dis- solved in ethylene glycol (20 mL). Then, this metal salt solution was added to the above SiO2 suspension fol- lowed by addition of hydrazine hydrate (85 wt% ...

  20. Method and means for producing solid evacuated microspheres of hydrogen

    International Nuclear Information System (INIS)

    Turnbull, R.J.; Foster, C.A.; Hendricks, C.D.

    1976-01-01

    A method is provided for producing solid, evacuated microspheres comprised of hydrogen. The spheres are produced by forming a jet of liquid hydrogen and exciting mechanical waves on the jet of appropriate frequency so that the jet breaks up into drops with a bubble formed in each drop by cavitation. The drops are exposed to a pressure less than the vapor pressure of the liquid hydrogen so that the bubble which is formed within each drop expands. The drops which contain bubbles are exposed to an environment having a pressure just below the triple point of liquid hydrogen and they hereby freeze giving solid, evacuated spheres of hydrogen. 4 claims, 1 fig

  1. Power output and efficiency of beta-emitting microspheres

    OpenAIRE

    Cheneler, David; Ward, Michael C L

    2015-01-01

    Current standard methods to calculate the dose of radiation emitted during medical applications by beta-minus emitting microspheres rely on an over-simplistic formalism. This formalism is a function of the average activity of the radioisotope used and the physiological dimensions of the patient only. It neglects the variation in energy of the emitted beta particle due to self-attenuation, or self-absorption, effects related to the finite size of the sphere. Here it is assumed the sphere is co...

  2. Magnetic Ganoderma lucidum spore microspheres: A novel material to immobilize CotA multicopper oxidase for dye decolorization

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Lili [School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001 (China); Wang, Yan, E-mail: wangy_msn@hit.edu.cn [School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001 (China); Zhao, Min [College of Life Science, Northeast Forestry University, Harbin 150040 (China); Song, Jinzhu [School of Life Science and Technology, Harbin Institute of Technology, Harbin 150001 (China); Wang, Jueyu; Jin, Zijing [College of Life Science, Northeast Forestry University, Harbin 150040 (China)

    2016-08-05

    Highlights: • Hollow microspheres were obtained from Ganoderma lucidum spores. • Novel magnetic microspheres were prepared by load hollow spore microspheres with Fe{sub 3}O{sub 4} nanoparticles. • CotA multicopper oxidase was immobilized on the magnetic spore microspheres for indigo carmine decolorization. • The immobilized CotA displayed higher decolorization capability and reusability. - Abstract: In this study, hollow microspheres were obtained from Ganoderma lucidum spores. Then the hollow microspheres were loaded with Fe{sub 3}O{sub 4} nanoparticles to prepare novel magnetic spore microspheres. TEM images and X-ray diffractometry demonstrated that the Fe{sub 3}O{sub 4} nanoparticles were incorporated throughout the spore microsphere. CotA multicopper oxidase was chosen as biomacromolecule to study the loading ability of the magnetic spore microspheres. The combination of the CotA enzyme with the microsphere was observed by laser scanning confocal microscope. The loaded amount of CotA on the microspheres was 75 mg/g when the CotA concentration was 1.2 mg/mL and the activity recovery of the immobilized CotA was 81%. The magnetic microspheres loaded with CotA, which can be easily and quickly recovered by an external magnetic field, were used for dye decolorization. After 1 h decolorization, 99% of the indigo carmine has been removed by 10 mg microspheres. In addition, the immobilized CotA retained 75% of activity after 10 consecutive cycles, which indicated that the magnetic spore microspheres are good support material for immobilization of the enzyme.

  3. Magnetic Ganoderma lucidum spore microspheres: A novel material to immobilize CotA multicopper oxidase for dye decolorization

    International Nuclear Information System (INIS)

    Fan, Lili; Wang, Yan; Zhao, Min; Song, Jinzhu; Wang, Jueyu; Jin, Zijing

    2016-01-01

    Highlights: • Hollow microspheres were obtained from Ganoderma lucidum spores. • Novel magnetic microspheres were prepared by load hollow spore microspheres with Fe 3 O 4 nanoparticles. • CotA multicopper oxidase was immobilized on the magnetic spore microspheres for indigo carmine decolorization. • The immobilized CotA displayed higher decolorization capability and reusability. - Abstract: In this study, hollow microspheres were obtained from Ganoderma lucidum spores. Then the hollow microspheres were loaded with Fe 3 O 4 nanoparticles to prepare novel magnetic spore microspheres. TEM images and X-ray diffractometry demonstrated that the Fe 3 O 4 nanoparticles were incorporated throughout the spore microsphere. CotA multicopper oxidase was chosen as biomacromolecule to study the loading ability of the magnetic spore microspheres. The combination of the CotA enzyme with the microsphere was observed by laser scanning confocal microscope. The loaded amount of CotA on the microspheres was 75 mg/g when the CotA concentration was 1.2 mg/mL and the activity recovery of the immobilized CotA was 81%. The magnetic microspheres loaded with CotA, which can be easily and quickly recovered by an external magnetic field, were used for dye decolorization. After 1 h decolorization, 99% of the indigo carmine has been removed by 10 mg microspheres. In addition, the immobilized CotA retained 75% of activity after 10 consecutive cycles, which indicated that the magnetic spore microspheres are good support material for immobilization of the enzyme.

  4. Sandwich-structure-modulated photoluminescence enhancement of wide bandgap semiconductors capping with dielectric microsphere arrays.

    Science.gov (United States)

    Yang, Lixue; Yan, Yinzhou; Wang, Qiang; Zeng, Yong; Liu, Feifei; Li, Lin; Zhao, Yan; Jiang, Yijian

    2017-03-20

    Here we investigated the effect of substrate and film thickness on photoluminescence (PL) enhancement of wide bandgap semiconductor (i.e. ZnO) by dielectric microsphere array/luminescence film/substrate (MLS) sandwich structures. The PL enhancement channels in the sandwich structure were revealed, for the first time, including the focusing property of microsphere array (MSA) distinctly enhancing free-exciton recombination, anti-reflection effect of MSA increasing excitation cross-section area, MLS-supported TW-/SW-WGMs inducing ASE and Purcell's effect, and optical directional antenna effect for high equivalent NA of objective lens as well as out-coupling efficiency. The enhancement ratio of intensity (ERI) for ZnO UV-PL from free-exciton recombination in the sandwich structure was found to be strongly dependent upon the refractive index of substrate and luminescence film thickness. In order to achieve high ERI for PL emission, the refractive index of substrate should differ from luminescence film and the film thickness needs to be chosen to support WGMs in the sandwich structure. The maximum ERI beyond one order of magnitude for ZnO UV-PL was therefore predicted theoretically and validated experimentally, where 11.25-fold UV PL enhancement ratio was achieved in ~650-nm-thick ZnO film grown on SiC substrate and capped with 5.06-μm-diameter MSA. The ERI could further be increased by improving above-mentioned enhancement channels. The present work provides a novel platform to manipulate light by low-loss dielectric microstructures for enhancing photon-matter interaction, which would be employed for other semiconductors achieving energy-saving luminescence and high-sensitivity photoelectric detection in future.

  5. radio embolization of yttrium 90 glass microspheres in treatment of hepatocellular carcinoma

    International Nuclear Information System (INIS)

    El Fouly, A.H.A.

    2010-01-01

    Hepatocellular carcinoma (HCC) is a common cancer that typically occurs in the setting of cirrhosis and chronic hepatitis virus infections. HCC is considered currently as global problem; its incidence is expected to increase dramatically by the next few decades. More than 90 % of the accidentally diagnosed patients have non resectable tumor. Portal vein thrombosis, diffuse multifocal liver infiltration and large tumor burden are considered to be a great obstacle in front of the modern lines of treatment, even with Child A liver cirrhosis. Transarterial intrahepatic application of Yttrium-90 glass microspheres may allow effective local ablative treatment of patients with intrahepatic advanced hepatocellular carcinoma (HCC) with or without portal vein thrombosis. The aim of this open-label phase II study was to validate evidence on the safety and efficacy of this treatment in an European cohort of patients with locally advanced HCC such as (large tumor burden, multifocal distribution, portal vein thrombosis). And to assess the response rate according to different approved response assessment guidelines (WHO, RECIST and EASL). Patients and Methods Starting from November 2006 till March 2009, one hundred and eight advanced unresectable HCC patients with and without portal vein thrombosis were included in this prospective study. Yttrium-90 microspheres radiotherapy was performed in a lobar fashion through the right or left hepatic artery. In bilobar disease, right and left liver lobe were treated with 4-6 weeks intervals in between. Response rate was assessed according to different international response assessment criteria (WHO, RECIST and EASL) with sequential computed tomography scans till the last clinical visit or death. The safety of this technique was assessed according to the Common Toxicity Criteria version 3

  6. Preparation of hollow microspheres of Ce{sup 3+} doped NiCo ferrite with high microwave absorbing performance

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Hong-zhen, E-mail: duanhz2000@163.com; Zhou, Fang-ling; Cheng, Xia; Chen, Guo-hong; Li, Qiao-ling

    2017-02-15

    Hollow microspheres of Ce{sup 3+} doped NiCo-ferrites were synthesized by template-based-deposition and surface reaction method with carbon sphere as the template. The phase structure, morphology, magnetic properties and wave absorbing properties of the sample were characterized by X-ray powder diffraction(XRD), Scanning electronic microscopy(SEM), Vibration sample magnetometer (VSM) and a network vector analyzer (NVA), respectively. The results indicated that the particle size of the carbon sphere sample prepared by hydrothermal method was about 0.5 µm and the particle size of the Ni{sub 0.5}Co{sub 0.5}Fe{sub 2}O{sub 4} sample prepared by template-based method was about 300 nm. The influence of the amount of rare earth element on the magnetic and absorbing properties of sample was studied. The saturation magnetization and coercivity decreased gradually with the increase of the content of Ce. When the content of Ce was 0.02, the maximal saturation magnetization value and coercivity was 75.72 emu• g{sup −1} and 789.88 Oe, respectively. The associated ferrite hollow spheres have good absorbing performance, and the return loss value was −18.8 dB at 5500 MHz. - Highlights: • Hollow microspheres of Ce{sup 3+} doped NiCo-ferrites were synthesized by template-based-deposition and surface reaction method. • The influence of rare earth Ce{sup 3+} on the magnetic and absorbing properties of sample was studied. • When the content of Ce was 0.02, the maximal saturation magnetization value and coercivity was 75.72 emu• g{sup −1} and 789.88 Oe, respectively.

  7. Fluorocarbon-bonded magnetic mesoporous microspheres for the analysis of perfluorinated compounds in human serum by high-performance liquid chromatography coupled to tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiaodan; Yu, Yingjia [Department of Pharmaceutical Analysis, School of Pharmacy, Fudan University, No. 826 Zhangheng Road, Shanghai 201203 (China); Li, Yan, E-mail: yanli@fudan.edu.cn [Department of Pharmaceutical Analysis, School of Pharmacy, Fudan University, No. 826 Zhangheng Road, Shanghai 201203 (China); Zhang, Haiying [Department of Biology, Dezhou University, Shandong 253023 (China); Ling, Jin; Sun, Xueni; Feng, Jianan; Duan, Gengli [Department of Pharmaceutical Analysis, School of Pharmacy, Fudan University, No. 826 Zhangheng Road, Shanghai 201203 (China)

    2014-09-24

    Highlights: • New SPE method was developed for analysis of PFCs in human serum. • Fluorocarbon-bonded magnetic mesoporous microspheres were used as SPE absorbents. • PFCs in serum were directly extracted without any other pretreatment procedure. • The PFCs-adsorbed microspheres were simply and rapidly isolated by using a magnet. - Abstract: We report herein an extraction method for the analysis of perfluorinated compounds in human serum based on magnetic core–mesoporous shell microspheres with decyl-perfluorinated interior pore-walls (Fe{sub 3}O{sub 4}@mSiO{sub 2}-F{sub 17}). Thanks to the unique properties of the Fe{sub 3}O{sub 4}@mSiO{sub 2}-F{sub 17} microspheres, macromolecules like proteins could be easily excluded from the mesoporous channels due to size exclusion effect, and perfluorinated compounds (PFCs) in protein-rich biosamples such as serum could thus be directly extracted with the fluorocarbon modified on the channel wall without any other pretreatment procedure. The PFCs adsorbed Fe{sub 3}O{sub 4}@mSiO{sub 2}-F{sub 17} microspheres could then be simply and rapidly isolated by using a magnet, followed by being identified and quantified by LC–MS/MS (high-performance liquid chromatography coupled to tandem mass spectrometry). Five perfluorinatedcarboxylic acids (C6, C8–C11) and perfluorooctane sulfonate (PFOS) were selected as model analytes. In order to achieve the best extraction efficiency, some important factors including the amount of Fe{sub 3}O{sub 4}@mSiO{sub 2}-F{sub 17} microspheres added, adsorption time, type of elution solvent, eluting solvent volume and elution time were investigated. The ranges of the LOD were 0.02–0.05 ng mL{sup −1} for the six PFCs. The recovery of the optimized method varies from 83.13% to 92.42% for human serum samples.

  8. Investigation of plasmon properties of silver microsphere array demonstrated experimentally by tip-enhanced Raman spectroscopy

    Science.gov (United States)

    Liu, Yanqi; Zhao, Lijiang; Li, Xinjuan; Zeng, Zhuo; Wang, Peijie; Zhang, Lisheng; Fang, Yan

    2018-01-01

    Due to high spatial resolution and extraordinarily high detection sensitivity of tip-enhanced Raman spectroscopy (TERS), it has attracted more and more attention. However, the tip size and shape, and tip substrate distance have a large impact on the TERS enhancement properties. In this study, a silver microsphere array was prepared on a Polystyrene (PS) microsphere array by vacuum thermal evaporation. And the correlation between the properties of two-dimensional surface-enhanced Raman scattering (SERS) mapping of rhodamine 6G (Rh6G) absorbed on the silver microsphere array and the polarization direction of the incident light was investigated. The effect of the location of the tip on the surface plasmon distribution of the silver microsphere array was also revealed in TERS. In addition, the surface electromagnetic field distribution of the silver microsphere array was simulated by three-dimensional finite-difference time domain (3D-FDTD) method. These results show that the distribution of 'hot spots' on the surface of the silver microsphere array has a dependency on the polarization direction of the incident laser. Moreover, with the introduction of the tip, the 'hot spot' on the surface of the silver microsphere array becomes much more localized and largely enhanced. These results obtained in this paper may have some significance for further studies on the surface plasmon resonance bio-sensing.

  9. Controlled Release of Lysozyme from Double-Walled Poly(Lactide-Co-Glycolide (PLGA Microspheres

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    Rezaul H. Ansary

    2017-10-01

    Full Text Available Double-walled microspheres based on poly(lactide-co-glycolide (PLGA are potential delivery systems for reducing a very high initial burst release of encapsulated protein and peptide drugs. In this study, double-walled microspheres made of glucose core, hydroxyl-terminated poly(lactide-co-glycolide (Glu-PLGA, and carboxyl-terminated PLGA were fabricated using a modified water-in-oil-in-oil-in-water (w1/o/o/w2 emulsion solvent evaporation technique for the controlled release of a model protein, lysozyme. Microspheres size, morphology, encapsulation efficiency, lysozyme in vitro release profiles, bioactivity, and structural integrity, were evaluated. Scanning electron microscopy (SEM images revealed that double-walled microspheres comprising of Glu-PLGA and PLGA with a mass ratio of 1:1 have a spherical shape and smooth surfaces. A statistically significant increase in the encapsulation efficiency (82.52% ± 3.28% was achieved when 1% (w/v polyvinyl alcohol (PVA and 2.5% (w/v trehalose were incorporated in the internal and external aqueous phase, respectively, during emulsification. Double-walled microspheres prepared together with excipients (PVA and trehalose showed a better control release of lysozyme. The released lysozyme was fully bioactive, and its structural integrity was slightly affected during microspheres fabrication and in vitro release studies. Therefore, double-walled microspheres made of Glu-PLGA and PLGA together with excipients (PVA and trehalose provide a controlled and sustained release for lysozyme.

  10. Fabrication of Magnetic-Antimicrobial-Fluorescent Multifunctional Hybrid Microspheres and Their Properties

    Directory of Open Access Journals (Sweden)

    Ling-Han Xiao

    2013-04-01

    Full Text Available Novel magnetic-antimicrobial-fluorescent multifunctional hybrid microspheres with well-defined nanostructure were synthesized by the aid of a poly(glycidyl methacrylate (PGMA template. The hybrid microspheres were fully characterized by scanning electron microscopy (SEM, transmission electron microscopy (TEM, Fourier transform infrared (FTIR, X-ray diffraction (XRD and digital fluorescence microscope. The as-synthesized microspheres PGMA, amino-modified PGMA (NH2-PGMA and magnetic PGMA (M-PGMA have a spherical shape with a smooth surface and fine monodispersity. M-PGMA microspheres are super-paramagnetic, and their saturated magnetic field is 4.608 emu·g−1, which made M-PGMA efficiently separable from aqueous solution by an external magnetic field. After poly(haxemethylene guanidine hydrochloride (PHGH functionalization, the resultant microspheres exhibit excellent antibacterial performance against both Gram-positive and Gram-negative bacteria. The fluorescence feature originating from the quantum dot CdTe endowed the hybrid microspheres with biological functions, such as targeted localization and biological monitoring functions. Combination of magnetism, antibiosis and fluorescence into one single hybrid microsphere opens up the possibility of the extensive study of multifunctional materials and widens the potential applications.

  11. A novel approach to preparing magnetic protein microspheres with core-shell structure

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Wei, E-mail: climentjw@126.co [National Special Superfine Powder Engineering Research Center, Nanjing University of Science and Technology, Nanjing 210094 (China); Sun Zhendong; Li Fengsheng [National Special Superfine Powder Engineering Research Center, Nanjing University of Science and Technology, Nanjing 210094 (China); Chen Kai; Liu Tianyu; Liu Jialing [Department of Physics, Nanjing University of Science and Technology, Nanjing 210094 (China); Zhou Tianle [Department of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Guo Rui [Department of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China)

    2011-03-15

    Magnetic protein microspheres with core-shell structure were prepared through a novel approach based on the sonochemical method and the emulsion solvent evaporation method. The microspheres are composed of the oleic acid and undecylenic acid modified Fe{sub 3}O{sub 4} cores and coated with globular bovine serum albumin (BSA). Under an optimized condition, up to 57.8 wt% of approximately 10 nm superparamagnetic Fe{sub 3}O{sub 4} nanoparticles could be uniformly encapsulated into the BSA microspheres with the diameter of approximately 160 nm and the high saturation magnetization of 38.5 emu/g, besides of the abundant functional groups. The possible formation mechanism of magnetic microspheres was discussed in detail. - Research Highlights: Magnetic protein microspheres with core-shell structure were prepared through a novel approach based on the sonochemical method and the emulsion solvent evaporation method. The microspheres are composed of the oleic acid and undecylenic acid modified Fe{sub 3}O{sub 4} cores and coated with globular bovine serum albumin (BSA). 57.8 wt% of approximately 10 nm superparamagnetic Fe{sub 3}O{sub 4} nanoparticles could be uniformly encapsulated into the BSA microspheres with the diameter of approximately 160 nm and the high saturation magnetization of 38.5 emu/g, besides the abundant functional groups.

  12. Ammonolysis-induced solvent removal: a facile approach for solidifying emulsion droplets into PLGA microspheres.

    Science.gov (United States)

    Kim, Jayoung; Hong, Dasom; Chung, Younglim; Sah, Hongkee

    2007-12-01

    An ammonolysis-based microencapsulation technique useful for the preparation of biodegradable microspheres was described in this study. A dispersed phase consisting of poly- d, l-lactide- co-glycolide, progesterone, and methyl chloroacetate was emulsified in an aqueous phase. Upon addition of ammonia solution, the emulsion droplets were quickly transformed into poly- d, l-lactide- co-glycolide microspheres laden with progesterone. Rapid solvent removal was accompanied by ammonolysis. The chemical reaction converted water-immiscible methyl chloroacetate to water-miscible chloroacetamide and methanol. Chloroacetamide formation was proved by (1)H NMR and ESI-MS studies. Thermogravimetric analysis showed that the microspheres contained only small amounts of residual methyl chloroacetate. Incorporation efficiencies of progesterone ranged from 64.3 +/- 1.1 to 72.8 +/- 0.3%, depending upon microsphere formulations. X-ray powder diffractometry analysis substantiated that no polymorphic transition of progesterone occurred during microencapsulation. To evaluate the feasibility of this new method against the commonly used microencapsulation method, microspheres were also prepared by a typical dichloromethane-based solvent evaporation process. The important attributes of microspheres prepared from both methods were characterized for comparison. The new ammonolysis-based microencapsulation process showed interesting features distinct from those of the solvent evaporation process. The microencapsulation process reported in this study might be applicable in loading pharmaceuticals into various polymeric microspheres.

  13. Synthesis and effect of modification on methacylate - acrylate microspheres for Trametes versicolor laccase enzyme immobilization

    Science.gov (United States)

    Mazlan, Siti Zulaikha; Hanifah, Sharina Abu

    2014-09-01

    Immobilization of laccase on the modified copolymer methacrylate-acrylate microspheres was studied. A poly (glycidyl methacrylate-co-n-butyl acrylate) microsphere consists of epoxy groups were synthesized using suspension photocuring technique. The epoxy group in poly (GMA-nBA) microspheres were converted into amino groups with aldehyde group. Laccase immobilization is based on having the amino groups on the enzyme surface and aldehyde group on the microspheres via covalent binding. Fourier transform infrared spectroscopy (FT-IR) analysis proved the successful surface modification on microspheres. The FTIR spectrum shows the characteristic peaks at 1646 cm-1 assigned to the conformation of the polymerization that took place between monomer GMA and nBA respectively. In addition, after modification, FTIR peaks that assigned to the epoxy ring (844 cm-1 and 904 cm-1) were decreased. The results obtained from FTIR method signify good agreement with the epoxy content method. Hence, the activity of the laccase-immobilized microspheres increased upon increasing the epoxy content. Furthermore, poly (GMA-nBA) exhibited uniform microspheres with below 2 μm surface. Immobilized enzyme showed a broader pH profile and higher temperature compared native enzyme.

  14. Degradation behavior of theophylline/chitosan/β-cyclodextrin microspheres for pulmonary drug delivery

    Directory of Open Access Journals (Sweden)

    Li Wang

    2016-04-01

    Full Text Available To evaluate the degradation behavior of theophylline/chitosan/β-cyclo-dextrin microspheres, we performed both in vitro study by putting the microspheres in phosphate buffered saline or in phosphate buffer saline with enzyme and in vivo study by implanting the microspheres into the back of male Sprague-Dawley rats. The results showed that microspheres were degraded in enzymatic hydrolysis and phosphate buffer saline, which were degraded faster in 0.2 mg/mL lysozyme than in phosphate buffer saline. The morphology of microspheres in phosphate buffer saline and enzyme solution developed rough surfaces, and showed irregular shape and pores after 8 weeks. The microspheres were degraded in vivo within 8 weeks with irregular, sheet, porous morphology, and the diameters were smaller than 5 μm. These results indicated that the theophylline/chitosan/β-cyclodextrin microspheres had a good degradation both in vitro and in vivo which can be used as a pulmonary drug delivery carrier.

  15. Preparation, Characterization, and Bioactivity of Chitosan Microspheres Containing Basic Fibroblast Growth Factor

    Directory of Open Access Journals (Sweden)

    Bo Lv

    2014-01-01

    Full Text Available The aim of this study is to evaluate, prepare, and characterize bioactivity of chitosan microspheres loaded with bFGF for providing sustained release of bFGF. Porous chitosan microspheres were prepared by freeze-drying process based on the interaction between chitosan and tripolyphosphate (TPP. The bFGF-loaded chitosan microspheres were well interconnected and have a narrow size distribution, spherical shape, and positive surface charges. The bFGF-loading capacity and encapsulation efficiency were 7.57 mg/g and 95.1%, respectively. Results of in vitro release showed that the extent of release was 82.1% at Day 25. Schwann cells were used as an in vitro model for cell response to bFGF and bFGF-loaded chitosan microspheres. Results indicated that the number, cell viability, and percentage of cells G2/M+S phase in the bFGF groups are higher than those in the bFGF-loaded chitosan microspheres groups before culturing for 2 days. However, the number, cell viability, and percent of cells G2/M+S phase in the bFGF-loaded chitosan microspheres groups are significantly higher than those in the bFGF groups after culture for 4 and 8 days. These findings indicated that bFGF-loaded chitosan microspheres may help to decrease the release of bFGF and provide a suitable three-dimensional environment for cell growth and proliferation.

  16. A novel approach to preparing magnetic protein microspheres with core-shell structure

    International Nuclear Information System (INIS)

    Jiang Wei; Sun Zhendong; Li Fengsheng; Chen Kai; Liu Tianyu; Liu Jialing; Zhou Tianle; Guo Rui

    2011-01-01

    Magnetic protein microspheres with core-shell structure were prepared through a novel approach based on the sonochemical method and the emulsion solvent evaporation method. The microspheres are composed of the oleic acid and undecylenic acid modified Fe 3 O 4 cores and coated with globular bovine serum albumin (BSA). Under an optimized condition, up to 57.8 wt% of approximately 10 nm superparamagnetic Fe 3 O 4 nanoparticles could be uniformly encapsulated into the BSA microspheres with the diameter of approximately 160 nm and the high saturation magnetization of 38.5 emu/g, besides of the abundant functional groups. The possible formation mechanism of magnetic microspheres was discussed in detail. - Research Highlights: → Magnetic protein microspheres with core-shell structure were prepared through a novel approach based on the sonochemical method and the emulsion solvent evaporation method.→ The microspheres are composed of the oleic acid and undecylenic acid modified Fe 3 O 4 cores and coated with globular bovine serum albumin (BSA).→ 57.8 wt% of approximately 10 nm superparamagnetic Fe 3 O 4 nanoparticles could be uniformly encapsulated into the BSA microspheres with the diameter of approximately 160 nm and the high saturation magnetization of 38.5 emu/g, besides the abundant functional groups.

  17. Facile Synthesis of Mono-Dispersed Polystyrene (PS/Ag Composite Microspheres via Modified Chemical Reduction

    Directory of Open Access Journals (Sweden)

    Wen Zhu

    2013-12-01

    Full Text Available A modified method based on in situ chemical reduction was developed to prepare mono-dispersed polystyrene/silver (PS/Ag composite microspheres. In this approach; mono-dispersed PS microspheres were synthesized through dispersion polymerization using poly-vinylpyrrolidone (PVP as a dispersant at first. Then, poly-dopamine (PDA was fabricated to functionally modify the surfaces of PS microspheres. With the addition of [Ag(NH32]+ to the PS dispersion, [Ag(NH32]+ complex ions were absorbed and reduced to silver nanoparticles on the surfaces of PS-PDA microspheres to form PS/Ag composite microspheres. PVP acted both as a solvent of the metallic precursor and as a reducing agent. PDA also acted both as a chemical protocol to immobilize the silver nanoparticles at the PS surface and as a reducing agent. Therefore, no additional reducing agents were needed. The resulting composite microspheres were characterized by TEM, field emission scanning electron microscopy (FESEM, energy-dispersive X-ray spectroscopy (EDS, XRD, UV-Vis and surface-enhanced Raman spectroscopy (SERS. The results showed that Ag nanoparticles (NPs were homogeneously immobilized onto the PS microspheres’ surface in the presence of PDA and PVP. PS/Ag composite microspheres were well formed with a uniform and compact shell layer and were adjustable in terms of their optical property.

  18. Application of superparamagnetic microspheres for affinity adsorption and purification of glutathione

    International Nuclear Information System (INIS)

    Wang Qiang; Guan Yueping; Yang Mingzhu

    2012-01-01

    The superparamagnetic poly-(MA–DVB) microspheres with micron size were synthesized by the modified suspension polymerization method. Adsorption of glutathione by magnetic poly-(MA–DVB) microspheres with IDA-copper was investigated. The effect of solution pH value, affinity adsorption and desorption of glutathione was studied. The results showed that the optimum pH value for glutathione adsorption was found at pH=3.5, the maximum capacity for glutathione of magnetic poly-(MA–DVB) microspheres was estimated at 42.4 mg/g by fitting the experimental data to the Langmuir equation. The adsorption equilibrium of glutathione was obtained in about 10 min and the adsorbed glutathione was desorbed from the magnetic microspheres in about 30 min using NaCl buffer solution. The magnetic microspheres could be repeatedly utilized for the affinity adsorption of glutathione. - Highlights: ► The magnetic microsphere with surface IDA–Cu groups was synthesized. ► The magnetic microspheres were applied for adsorption of GSH. ► The adsorption–desorption of glutathione was investigated. ► The maximum adsorption capacity of GSH was fitted at 42.4 mg/g.

  19. Preclinical and clinical in vitro in vivo correlation of an hGH dextran microsphere formulation.

    Science.gov (United States)

    Vlugt-Wensink, K D F; de Vrueh, R; Gresnigt, M G; Hoogerbrugge, C M; van Buul-Offers, S C; de Leede, L G J; Sterkman, L G W; Crommelin, D J A; Hennink, W E; Verrijk, R

    2007-12-01

    To investigate the in vitro in vivo correlation of a sustained release formulation for human growth hormone (hGH) based on hydroxyethyl methacrylated dextran (dex-HEMA) microspheres in Pit-1 deficient Snell dwarf mice and in healthy human volunteers. A hGH-loaded microsphere formulation was developed and tested in Snell dwarf mice (pharmacodynamic study) and in healthy human volunteers (pharmacokinetic study). Single subcutaneous administration of the microspheres in mice resulted in a good correlation between hGH released in vitro and in vivo effects for the hGH-loaded microsphere formulation similar to daily injected hGH indicating a retained bioactivity. Testing the microspheres in healthy volunteers showed an increase (over 7-8 days) in hGH serum concentrations (peak concentrations: 1-2.5 ng/ml). A good in vitro in vivo correlation was obtained between the measured and calculated (from in vitro release data) hGH serum concentrations. Moreover, an increased serum concentration of biomarkers (insulin-like growth factor-I (IGF-I), IGF binding protein-3 (IGFBP-3) was found again indicating that bioactive hGH was released from the microspheres. Good in vitro in vivo correlations were obtained for hGH-loaded dex-HEMA microspheres, which is an important advantage in predicting the effect of the controlled drug delivery product in a clinical situations.

  20. Novel Fabrication of Biodegradable Superabsorbent Microspheres with Diffusion Barrier through Thermo-Chemical Modification and Their Potential Agriculture Applications for Water Holding and Sustained Release of Fertilizer.

    Science.gov (United States)

    Feng, Diejing; Bai, Bo; Wang, Honglun; Suo, Yourui

    2017-07-26

    Synergistic utilization of water and fertilizer has vital contribution to the modern production of agriculture. This work reports on a simple and facile strategy to prepare biodegradable yeast/sodium alginate/poly(vinyl alcohol) superabsorbent microspheres with a diffusion barrier merit by thermo-chemical modification route. The integrated performances, including water absorbency, water retention, water evaporation ratio, leaching loss control, sustained-release behaviors, and degradation in soil, were systematically investigated. The results revealed that the modified microspheres were a triumphant water and fertilizer manager to effectively hold water and control the unexpected leakage of fertilizer for sustained release. Therefore, this work provides a promising approach to ameliorate the utilization efficiency of water and fertilizer in potential agriculture applications.

  1. Simple Synthesis of Molybdenum Disulfide/Reduced Graphene Oxide Composite Hollow Microspheres as Supercapacitor Electrode Material

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    Wei Xiao

    2016-09-01

    Full Text Available MoS2/RGO composite hollow microspheres were hydrothermally synthesized by using SiO2/GO microspheres as a template, which were obtained via the sonication-assisted interfacial self-assembly of tiny GO sheets on positively charged SiO2 microspheres. The structure, morphology, phase, and chemical composition of MoS2/RGO hollow microspheres were systematically investigated by a series of techniques such as FE-SEM, TEM, XRD, TGA, BET, and Raman characterizations, meanwhile, their electrochemical properties were carefully evaluated by CV, GCD, and EIS measurements. It was found that MoS2/RGO hollow microspheres possessed unique porous hollow architecture with high-level hierarchy and large specific surface area up to 63.7 m2·g−1. When used as supercapacitor electrode material, MoS2/RGO hollow microspheres delivered a maximum specific capacitance of 218.1 F·g−1 at the current density of 1 A·g−1, which was much higher than that of contrastive bare MoS2 microspheres developed in the present work and most of other reported MoS2-based materials. The enhancement of supercapacitive behaviors of MoS2/RGO hollow microspheres was likely due to the improved conductivity together with their distinct structure and morphology, which not only promoted the charge transport but also facilitated the electrolyte diffusion. Moreover, MoS2/RGO hollow microsphere electrode displayed satisfactory long-term stability with 91.8% retention of the initial capacitance after 1000 charge/discharge cycles at the current density of 3 A·g−1, showing excellent application potential.

  2. Formulation and Evaluation of Microsphere Based Oro Dispersible Tablets of Itopride Hcl

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    S.S Agrawal

    2012-09-01

    Full Text Available Background The purpose of the present work is to mask the intensely bitter taste of Itopride HCl and to formulate an Oro dispersible tablet (ODT of the taste-masked drug by incorporation of microspheres in the tablets for use in specific populations viz. pediatrics, geriatrics and patients experiencing difficulty in swallowing.Methods:With this objective in mind, microspheres loaded with Itopride HCl were prepared by solvent evaporation method using acetone as solvent for pH-sensitive polymer, Eudragit EPO and light liquid paraffin as the encapsulating medium. The prepared microspheres were characterized with regard to yield, drug content, flow properties, particle size and size distribution, surface features, in vitro drug release and taste. The ODTs so prepared from these microspheres were evaluated for hardness, thickness, weight variation, friability, disintegration time, drug content, wetting time, water absorption ratio, moisture uptake, in vitro dispersion, in vitro disintegration, in vitro drug release and stability. Results:The average size of microspheres was found to be satisfactory in terms of the size and size distribution. Microspheres prepared were of a regular spherical shape. Comparison of the dissolution profiles of microspheres in different pH media showed that microspheres having drug: polymer ratio of 1:2 produced a retarding effect in simulated salivary fluid (pH 6.8 and were further used for formulation into ODTs after addition of suitable amounts of excipients such as superdisintegrant, diluent, sweetener and flavor of directly compressible grade. ConclusionsEffective taste-masking was achieved for Itopride HCl by way of preparation of microspheres and ODTs of acceptable characteristics.

  3. Formulation and evaluation of microsphere based oro dispersible tablets of itopride hcl

    Directory of Open Access Journals (Sweden)

    Shah Sanjay

    2012-09-01

    Full Text Available Abstract Background The purpose of the present work is to mask the intensely bitter taste of Itopride HCl and to formulate an Oro dispersible tablet (ODT of the taste-masked drug by incorporation of microspheres in the tablets for use in specific populations viz. pediatrics, geriatrics and patients experiencing difficulty in swallowing. Methods With this objective in mind, microspheres loaded with Itopride HCl were prepared by solvent evaporation method using acetone as solvent for pH-sensitive polymer, Eudragit EPO and light liquid paraffin as the encapsulating medium. The prepared microspheres were characterized with regard to yield, drug content, flow properties, particle size and size distribution, surface features, in vitro drug release and taste. The ODTs so prepared from these microspheres were evaluated for hardness, thickness, weight variation, friability, disintegration time, drug content, wetting time, water absorption ratio, moisture uptake, in vitro dispersion, in vitro disintegration, in vitro drug release and stability. Results The average size of microspheres was found to be satisfactory in terms of the size and size distribution. Microspheres prepared were of a regular spherical shape. Comparison of the dissolution profiles of microspheres in different pH media showed that microspheres having drug: polymer ratio of 1:2 produced a retarding effect in simulated salivary fluid (pH 6.8 and were further used for formulation into ODTs after addition of suitable amounts of excipients such as superdisintegrant, diluent, sweetener and flavor of directly compressible grade. Conclusions Effective taste-masking was achieved for Itopride HCl by way of preparation of microspheres and ODTs of acceptable characteristics.

  4. Properties of dry masonry mixtures based on hollow aluminosilicate microspheres

    Directory of Open Access Journals (Sweden)

    Semenov Vyacheslav

    2017-01-01

    Full Text Available At present, there is a steady increase in the volume of housing construction in the Russian Federation. The modern trends in the field of energy and resource saving determine the need of the use of efficient building materials that ensure the safety, comfort and minimum cost of housing construction. Among the materials, often used for erecting of fencing structures, it is possible to note effective small-piece elements (ceramic and light-weight concrete units, etc.. To ensure the solidity of such structures, it is necessary to use the masonry mortars whose properties correspond to those of the main wall material. The existing dry mixes for obtaining of such mortars are expensive and often do not meet the minimum physical-and-mechanical and exploitation requirements. The solution of this problem is the usage of the hollow ceramics (aluminosilicate microspheres as a filler for such mixes. The article presents the results of studies of the main physical-and-mechanical and exploitation characteristics of dry masonry mixes with hollow ceramics microspheres modified with various chemical additives. The effect of the compounding factors on the average density and strength of dry masonry mixes was studied. The compositions have been optimized by the methods of mathematical planning.

  5. Toward automated formation of microsphere arrangements using multiplexed optical tweezers

    Science.gov (United States)

    Rajasekaran, Keshav; Bollavaram, Manasa; Banerjee, Ashis G.

    2016-09-01

    Optical tweezers offer certain advantages such as multiplexing using a programmable spatial light modulator, flexibility in the choice of the manipulated object and the manipulation medium, precise control, easy object release, and minimal object damage. However, automated manipulation of multiple objects in parallel, which is essential for efficient and reliable formation of micro-scale assembly structures, poses a difficult challenge. There are two primary research issues in addressing this challenge. First, the presence of stochastic Langevin force giving rise to Brownian motion requires motion control for all the manipulated objects at fast rates of several Hz. Second, the object dynamics is non-linear and even difficult to represent analytically due to the interaction of multiple optical traps that are manipulating neighboring objects. As a result, automated controllers have not been realized for tens of objects, particularly with three dimensional motions with guaranteed collision avoidances. In this paper, we model the effect of interacting optical traps on microspheres with significant Brownian motions in stationary fluid media, and develop simplified state-space representations. These representations are used to design a model predictive controller to coordinate the motions of several spheres in real time. Preliminary experiments demonstrate the utility of the controller in automatically forming desired arrangements of varying configurations starting with randomly dispersed microspheres.

  6. Stabilization of Tetanus Toxoid Encapsulated in PLGA Microspheres

    Science.gov (United States)

    Jiang, Wenlei; Schwendeman, Steven P.

    2014-01-01

    Delivery of vaccine antigens from controlled-release poly(lactic/glycolic acid) (PLGA) microspheres is a novel approach to reduce the number of antigen doses required for protection against infection. A major impediment to developing single-shot vaccines is encapsulated antigen instability during months of exposure to physiological conditions. For example, efforts to control neonatal tetanus in developing countries with a single-dose TT vaccine have been plagued by poor stability of the 150 kDa formaldehyde-detoxified protein antigen, tetanus toxoid (TT) in PLGA microspheres. We examined the denatured states of PLGA-encapsulated TT, revealing two primary TT instability mechanisms: 1) protein aggregation mediated by formaldehyde and 2) acid-induced protein unfolding and epitope damage. Further, we systemically identified excipients which can efficiently inhibit TT aggregation and retain TT antigenicity under simulated deleterious conditions, i.e., elevated temperature and humidity. By employing these novel additives in the PLGA system, we report the slow and continuous release of high doses of TT for one month with retained antigen stability during bioerosion of PLGA. PMID:18710256

  7. Biocompatibility of Bletilla striata Microspheres as a Novel Embolic Agent

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    ShiHua Luo

    2015-01-01

    Full Text Available We have prepared Chinese traditional herb Bletilla striata into microspheres as a novel embolic agent for decades. The aim of this study was to evaluate the biocompatibility of Bletilla striata microspheres (BSMs. After a thermal test of BSMs in vitro, the cell biocompatibility of BSMs was investigated in mouse fibroblasts and human umbilical vein endothelial cells using the methyl tetrazolium (MTT assay. In addition, blood biocompatibility was evaluated. In vivo intramuscular implantation and renal artery embolization in rabbits with BSMs were used to examine the inflammatory response. The experimental rabbits did not develop any fever symptoms after injection of BSMs, and BSMs exhibited no cytotoxicity in cultured mouse fibroblasts and human umbilical vein endothelial cells. Additionally, BSMs exhibited high compatibility with red blood cells and no hemolysis activity. Intramuscular implantation with BSMs resulted in a gradually lessened mild inflammatory reaction that disappeared after eight weeks. The occlusion of small renal vessels was associated with a mild perivascular inflammatory reaction without significant renal and liver function damage. In conclusion, we believe that BSMs exhibit high biocompatibility and are a promising embolic agent.

  8. Minimizing resputtering of Pt-coated microspheres in a batch magnetron sputtering process

    International Nuclear Information System (INIS)

    Plake, A.L.

    1981-01-01

    Preventing DT loss from glass microspheres being smoothly coated with PT is needed during fabrication of laser fusion targets. Evidence indicates that the increase of substrate temperature due to resputtering will cause DT loss. Resputtering will prevent a smooth and uniform coating on these glass microspheres (140 μm in diameter). This paper reviews the method that was developed to find a set of coating conditions to minimize the DT loss, and still be able to produce thick smooth Pt coated glass microspheres

  9. Rapid method for the labeling of albumin microspheres with 113In and 111In: concise communication

    International Nuclear Information System (INIS)

    Hagan, P.L.; Krejcarek, G.E.; Taylor, A.; Alazraki, N.

    1978-01-01

    A rapid and simple method for preparing microspheres labeled with In-113m or In-111 is described. The procedure requires 10 min and gives labeling yields approaching 100%. Biodistribution studies in rats, mice, and dogs show the product to be biologically stable, with approximately 90% of the injected dose localized in the lung at 1 hr postinjection. The convenient production of In-113m or In-111 albumin microspheres provides an alternate radiopharmaceutical to complement or substitute for Tc-99m microspheres in lung perfusion imaging and other circulation studies

  10. Formation of microspheres under the action of femtosecond laser radiation on titanium samples in hydrocarbons

    Science.gov (United States)

    Kochuev, D. A.; Khorkov, K. S.; Ivashchenko, A. V.; Prokoshev, V. G.; Arakelian, S. M.

    2018-01-01

    This work describes the original method of laser synthesis of microspheres which contain titanium carbide. The formation of microspheres is carried out by the action of femtosecond laser radiation on the surface of titanium in the reaction medium - the ultimate hydrocarbon. The resulting microspheres have a high surface smoothness, a narrow particle size distribution, an average size of 1-3 μm. They can be used in applications of additive engineering, powder metallurgy as the main raw material, or as an alloying additive.

  11. Preparation and Characterization of Chitosan Poly(acrylic acid Magnetic Microspheres

    Directory of Open Access Journals (Sweden)

    Hong-Zhong Li

    2010-07-01

    Full Text Available Spherical microparticles, capable of responding to magnetic fields, were prepared by encapsulating dextran-coated Fe3O4 nanoparticles into chitosan poly(acrylic acid (PAA microspheres template. The obtained magnetic microspheres were characterized by transmission electron microscopy (TEM, Fourier transform infrared spectroscopy (FT-IR, scanning electron microscopy (SEM, X-ray powder diffraction (XRD, and thermogravimetry (TG. The results showed that the microspheres were formed and demonstrated magnetic behavior in an applied magnetic field. In addition, magnetite particles were well encapsulated and the composite particles have high magnetite content, which was more than 40%.

  12. Fabrication and optical trapping of handling structures for reconfigurable microsphere magnifiers

    DEFF Research Database (Denmark)

    Bañas, Andrew Rafael; Vizsnyiczai, Gaszton; Búzás, András

    2013-01-01

    We demonstrate the use of microfabricated supporting structures for maneuvering and supporting polystyrene microspheres for use as magnifying lenses in imaging applications. The supporting structure isolates the trapping light from the magnifier, hence avoiding direct radiation to the sample being...... observed which could be damaging, especially for biological specimens. Using an optical trapping setup, we demonstrate the actuation of a microsphere not held by optical traps, and show the possibility of imaging through such microspheres. © (2013) COPYRIGHT Society of Photo-Optical Instrumentation...

  13. Modeling the Deformation-Failure Mechanisms of Thin Hollow Glass Microspheres

    Science.gov (United States)

    Garza-Cruz, Tryana V.; Nakagawa, Masami

    2009-06-01

    Thin Hollow Glass Microspheres (HGMs) are a potential candidate to insulate cryogenic tanks due to their high strength-to-weight ratio and thermal properties. In this study, HGMs were modeled using a Discrete Element Method (DEM) to simulate their deformation and fracture behavior. Due to lack of actual data, a chemical composition-based methodology was introduced to synthesize material properties that reproduce the mechanical properties of soda-lime-borosilicate glass. The modeled microsphere was subjected to a uniaxial compression test and failed due to buckling. This model captures some essential aspect of deformation-failure characteristics of a thin hollow glass microsphere.

  14. Comparative Study Using 100–300 Versus 300–500 μm Microspheres for Symptomatic Patients Due to Enlarged-BPH Prostates

    Energy Technology Data Exchange (ETDEWEB)

    Gonçalves, Octavio Meneghelli, E-mail: octaviogalvao@hotmail.com; Carnevale, Francisco Cesar, E-mail: francisco.carnevale@criep.com.br; Moreira, Airton Mota, E-mail: motamoreira@gmail.com [University of Sao Paulo Medical School, Interventional Radiology Unit (Brazil); Antunes, Alberto Azoubel, E-mail: antunesuro@uol.com.br [University of Sao Paulo Medical School, Division of Urology (Brazil); Rodrigues, Vanessa Cristina, E-mail: vanessapaular@yahoo.com.br [University of Sao Paulo Medical School, Interventional Radiology Unit (Brazil); Srougi, Miguel, E-mail: srougi@terra.com.br [University of Sao Paulo Medical School, Division of Urology (Brazil)

    2016-10-15

    PurposeThe purpose of the study was to compare safety and efficacy outcomes following prostate artery embolization (PAE) for the treatment of lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH) with 100–300 versus 300–500 μm tris-acryl gelatin microspheres.Materials and MethodsPatients were prospectively treated between August 2011 and June 2013 to receive PAE with 100–300 μm (group A) or 300–500 μm (group B) tris-acryl gelatin microspheres. Patients were followed for a minimum of 12 months and were assessed for changes in International Prostate Symptom Score (IPSS), quality of life (QoL) index, prostate volume determined by magnetic resonance imaging, serum prostate specific antigen (PSA), and maximum urine flow rate (Q{sub max}), as well as any treatment-related adverse events.ResultsFifteen patients were included in each group, and PAE was technically successful in all cases. Both groups experienced significant improvement in mean IPSS, QoL, prostate volume, PSA, and Q{sub max} (p < 0.05 for all). The differences observed between the two groups included a marginally insignificant more adverse events (p = 0.066) and greater mean serum PSA reduction at 3 months of follow-up (p = 0.056) in group A.ConclusionsBoth 100–300 and 300–500 μm microspheres are safe and effective embolic agents for PAE to treat LUTS-related to BPH. Although functional and imaging outcomes did not differ significantly following use of the two embolic sizes, the greater incidence of adverse events with 100–300 μm microspheres suggests that 300–500 μm embolic materials may be more appropriate.

  15. Microspheres for the oral delivery of insulin: preparation, evaluation and hypoglycaemic effect in streptozotocin-induced diabetic rats.

    Science.gov (United States)

    Zhang, Huan; Wang, Weimei; Li, Haoran; Peng, Yi; Zhang, Zhiqing

    2018-01-01

    Insulin-loaded microspheres were prepared by alternating deposition film layers that were composed of insulin and poly(vinyl sulfate) potassium on the surface of poly(lactic acid) (PLA) microspheres. The preparation of the insulin-loaded microspheres was optimized by an orthogonal test design, and the relationship between drug loading (DL) and film layers was studied. The particle size, DL and encapsulation efficiency of the obtained insulin-loaded microspheres with 10 films were 5.25 ± 0.15 µm, 111.33 ± 1.15 mg/g and 33.7 ± 0.19%, respectively. Following this, the physical characteristics of the insulin-loaded microspheres were investigated. The results from scanning electron microscopy and a laser particle size analyzer (LPSA) indicated the spherical morphology, rough surface and increasing particle sizes of the insulin-loaded microspheres, which were compared to those of PLA microspheres. An in vitro release study showed that the insulin-loaded microspheres were stable in HCl solution (pH 1.0) and released insulin slowly in phosphate-buffered solution (pH 6.8). Finally, the drug efficacy of the prepared insulin-loaded microspheres via oral administration was evaluated in rats with diabetes induced by streptozotocin, and an obvious dose-dependent hypoglycemic effect was observed. This preliminary data could illustrate the prospect of using microspheres for the oral delivery of insulin.

  16. Effect of WOW process parameters on morphology and burst release of FITC-dextran loaded PLGA microspheres.

    Science.gov (United States)

    Mao, Shirui; Xu, Jing; Cai, Cuifang; Germershaus, Oliver; Schaper, Andreas; Kissel, Thomas

    2007-04-04

    Using fluorescein isothiocyanate labeled dextran (FITC-dextran 40, FD40) as a hydrophilic model compound, microspheres were prepared by a WOW double emulsion technique. Influence of process parameters on microsphere morphology and burst release of FD40 from PLGA microspheres was studied. Internal morphology of microspheres was investigated by stereological method via cryo-cutting technique and scanning electron microscopy (SEM). Drug distribution in microspheres was observed with confocal laser scanning microscopy (CLSM). Polymer nature (RG503 and RG503H) had significant influence on the micro-morphology of microspheres. Increase in continuous water phase volume (W2) led to increased surface porosity but decreased internal porosity. By increasing PVA concentration in the continuous phase from 0.1 to 1%, particle size changed marginally but burst release decreased from 12.2 to 5.9%. Internal porosity of microspheres decreased considerably with increasing polymer concentration. Increase in homogenization speed during the primary emulsion preparation led to decreased internal porosity. Burst release decreased with increasing drug loading but increased with drug molecular weight. Drug distribution in microspheres depended on preparation method. The porosity of microspheres decreased with time in the diffusion stage, but internal morphology had no influence on the release behavior in the bioerosion stage. In summary, surface porosity and internal morphology play a significant role in the release of hydrophilic macromolecules from biodegradable microspheres in the initial release phase characterized by pore diffusion.

  17. Formulation, evaluation and 3(2) full factorial design-based optimization of ondansetron hydrochloride incorporated taste masked microspheres.

    Science.gov (United States)

    Kharb, Vandana; Saharan, Vikas Anand; Dev, Kapil; Jadhav, Hemant; Purohit, Suresh

    2014-11-01

    Masking the bitter taste of Ondansetron hydrochloride (ONS) may improve palatability, acceptance and compliance of ONS products. ONS-loaded, taste-masked microspheres were prepared with a polycationic pH-sensitive polymer and 3(2) full factorial design (FFD) was applied to optimize microsphere batches. Solvent evaporation, in acetone--methanol/liquid paraffin system, was used to prepare taste-masked ONS microspheres. The effect of varying drug/polymer (D/P) ratios on microspheres characteristics were studied by 3(2) FFD. Desirability function was used to search the optimum formulation. Microspheres were evaluated by FTIR, XRD and DSC to examine interaction and effect of microencapsulation process. In vitro taste assessment approach based on bitterness threshold and drug release was used to assess bitterness scores. Prepared ONS microspheres were spherical and surface was wrinkled. ONS was molecularly dispersed in microspheres without any incompatibility with EE100. In hydrochloric acid buffer pH 1.2, ONS released completely from microsphere in just 10 min. Contrary to this, ONS release at initial 5 min from taste-masked microspheres was less than the bitterness threshold. Full factorial design and in vitro taste assessment approach, coupled together, was successfully applied to develop and optimize batches of ONS incorporated taste-masked microspheres.

  18. {sup 18}F-labeled resin microspheres as surrogates for {sup 90}Y resin microspheres used in the treatment of hepatic tumors: a radiolabeling and PET validation study

    Energy Technology Data Exchange (ETDEWEB)

    Selwyn, R G [Department of Medical Physics, University of Wisconsin, Madison, WI 53706 (United States); Avila-Rodriguez, M A [Department of Medical Physics, University of Wisconsin, Madison, WI 53706 (United States); Converse, A K [Waisman Center, University of Wisconsin, Madison, WI 53706 (United States); Hampel, J A [Waisman Center, University of Wisconsin, Madison, WI 53706 (United States); Jaskowiak, C J [Department of Radiology, University of Wisconsin, Madison, WI 53706 (United States); McDermott, J C [Department of Radiology, University of Wisconsin, Madison, WI 53706 (United States); Warner, T F [Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, WI 53706 (United States); Nickles, R J [Department of Medical Physics, University of Wisconsin, Madison, WI 53706 (United States); Thomadsen, B R [Department of Medical Physics, University of Wisconsin, Madison, WI 53706 (United States)

    2007-12-21

    {sup 90}Y-labeled resin microspheres (SIR-Spheres (registered) ) are currently used to treat patients with primary and metastatic solid liver tumors. This treatment is typically palliative since patients have exhausted all other standard treatment options. Improving the quality of life and extending patient survival are typical benchmarks for tracking patient response. However, the current method for predicting microsphere biodistributions with {sup 99m}Tc-labeled macroaggregated albumin (MAA) does not correlate well with patient response. This work presents the development of a new {sup 18}F-labeled resin microsphere to serve as a surrogate for the treatment microsphere and to employ the superior resolution and sensitivity of positron emission tomography (PET). The {sup 18}F microsphere biodistributions were determined in a rabbit using PET imaging and histological review. The PET-based uptake ratio was shown to agree with the histological findings to better than 3%. In addition, the radiolabeling process was shown to be rapid, efficient and relatively stable in vivo.

  19. Clinical impact of {sup 99m}Tc-MAA SPECT/CT-based dosimetry in the radioembolization of liver malignancies with {sup 90}Y-loaded microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Garin, Etienne [Cancer Institute Eugene Marquis, Department of Nuclear Medicine, Rennes (France); University of Rennes 1, Rennes (France); INSERM, U-991, Liver Metabolisms and Cancer, Rennes (France); Rolland, Yan [Cancer Institute Eugene Marquis, Department of Medical Imaging, Rennes (France); Laffont, Sophie [University of Rennes 1, Rennes (France); Edeline, Julien [University of Rennes 1, Rennes (France); INSERM, U-991, Liver Metabolisms and Cancer, Rennes (France); Cancer Institute Eugene Marquis, Department of Medical Oncology, Rennes (France)

    2016-03-15

    Radioembolization with {sup 90}Y-loaded microspheres is increasingly used in the treatment of primary and secondary liver cancer. Technetium-99 m macroaggregated albumin (MAA) scintigraphy is used as a surrogate of microsphere distribution to assess lung or digestive shunting prior to therapy, based on tumoral targeting and dosimetry. To date, this has been the sole pre-therapeutic tool available for such evaluation. Several dosimetric approaches have been described using both glass and resin microspheres in hepatocellular carcinoma (HCC) and liver metastasis. Given that each product offers different specific activities and numbers of spheres injected, their radiobiological properties are believed to lightly differ. This paper summarizes and discusses the available studies focused on MAA-based dosimetry, particularly concentrating on potential confounding factors like clinical context, tumor size, cirrhosis, previous or concomitant therapy, and product used. In terms of the impact of tumoral dose in HCC, the results were concordant and a response relationship and tumoral threshold dose was clearly identified, especially in studies using glass microspheres. Tumoral dose has also been found to influence survival. The concept of treatment intensification has recently been introduced, yet despite several studies publishing interesting findings on the tumor dose-metastasis relationship, no consensus has been reached, and further clarification is thus required. Nor has the maximal tolerated dose to the liver been well documented, requiring more accurate evaluation. Lung dose was well described, despite recently identified factors influencing its evaluation, requiring further assessment. MAA SPECT/CT dosimetry is accurate in HCC and can now be used in order to achieve a fully customized approach, including treatment intensification. Yet further studies are warranted for the metastasis setting and evaluating the maximal tolerated liver dose. (orig.)

  20. Characterization, Stability and Biological Activity In Vitro of Cathelicidin-BF-30 Loaded 4-Arm Star-Shaped PEG-PLGA Microspheres

    Directory of Open Access Journals (Sweden)

    Yueli Bao

    2018-02-01

    Full Text Available BF-30 is a single chain polypeptide of an N-segment with an α-helix from cathelicidin gene encoding, and it contains 30 amino acid residues, with a relative molecular mass and isoelectric point of 3637.54 and 11.79, respectively. Cathelicidin-BF-30 was entrapped in four-arm star-shaped poly(ethylene glycol-b-dl-lactic acid-co-glycolic acid block copolymers (4-arm-PEG-PLGA by a double-emulsion solvent-evaporation method. Three release phases of cathelicidin-BF-30loaded 4-arm-PEG-PLGA microspheres were observed, including an initial burst-release phase, followed by a lag phase with minimal drug release and finally a secondary zero-order release phase. The delivery system released BF-30 over more than 15 days in vitro. Furthermore, the material for preparing the microspheres has good biocompatibility and biodegradability. Additionally, based on the drug resistance of food pathogenic bacteria, the antibacterial effects of BF-30 on Shigella dysenteriae CMCC 51105 (Sh. dysenteriae CMCC 51105, Salmonella typhi (S. typhi and Staphylococcus aureus (S. aureus as well as the stability of the in vitro release of the BF-30-loded microspheres were studied. The α-helix secondary structure and antibacterial activity of released BF-30 were retained and compared with native peptide. These BF-30 loaded microspheres presented <10% hemolysis and no toxicity for HEK293T cells even at the highest tested concentration (150 μg/mL, indicating that they are hemocompatible and a promising delivery and protection system for BF-30 peptide.

  1. Hepatic vein tumor thrombus as a risk factor for excessive pulmonary deposition of microspheres during TheraSphere therapy for unresectable hepatocellular carcinoma.

    Science.gov (United States)

    Fleming, Chad J; Andrews, James C; Wiseman, Gregory A; Gansen, Denise N; Roberts, Lewis R

    2009-11-01

    To evaluate the impact of identifiable hepatic vein tumor thrombus on the ability to safely deliver TheraSphere (yttrium 90-containing glass microspheres) for the treatment of hepatocellular carcinoma (HCC). A retrospective review was performed of 87 patients (71 men, 16 women; mean age, 64.5 years; age range, 25-83 y) referred for TheraSphere therapy for HCC during a 2-year period between April 2005 and May 2007. Evaluation included contrast-enhanced computed tomography or magnetic resonance imaging, selective mesenteric angiography, and radionuclide perfusion scintigraphy to measure the arteriovenous shunting through the tumor. Of the 87 patients, 83 underwent angiography and perfusion scintigraphy; 53 were ultimately treated with 65 glass microsphere infusions. Twelve of 83 were identified as having tumor thrombus in a hepatic vein or extending into the inferior vena cava. The mean lung shunt for the patients with hepatic vein tumor thrombus was 30% (range, 11%-60%), compared with 8.2% (range, 3%-23%) for patients without identifiable tumor thrombus. Two of the 12 patients were treated with reduced doses of glass microspheres, and the remaining 10 were offered alternative therapies. The presence of hepatic vein tumor thrombus is a risk factor for an increased lung shunt that may prohibit delivery of a therapeutic dose of TheraSphere to hepatic tumor.

  2. Fabrication of a multiplexed microfluidic system for scaled up production of cross-linked biocatalytic microspheres

    CSIR Research Space (South Africa)

    Mbanjwa, M

    2014-06-01

    Full Text Available the design and fabrication of a multiplexed microfluidic system for producing biocatalytic microspheres. The microfluidic system consists of an array of 10 parallel microfluidic circuits, for simultaneous operation to demonstrate increased production...

  3. Properties and self-healing behavior of oil absorbent microspheres modified cement

    Science.gov (United States)

    Wang, Chunyu; Bu, Yuhuan; Zhao, Letian

    2017-09-01

    This paper concerns the properties and self-healing behavior of cement composites modified by oil absorbent microspheres with fumed silica shell. These microspheres, prepared by Pickering polymerization, possessed excellent properties, such as uniform particle size, good hydrophilicity and fine thermal stability. Furthermore, the effect of these microspheres on the properties of cement slurry was studied. The results showed that these microspheres had good compatibility with cement slurry, except for a slight effect on the consistency of cement slurry and the compressive strength of cement stone. At last, we derived the mathematical formulation of valid sealing for microcracks in self-healing cement, and measured sealing pressure under different filling conditions. The self-healing cement would guarantee the health, safety and high efficiency in the process of oil and gas production.

  4. Solution assisted growth mechanism and characterization of ZnS microspheres

    Science.gov (United States)

    Ghoderao, Karuna P.; Jamble, Shweta N.; Sawant, Jitendra P.; Kale, Rohidas B.

    2017-02-01

    The ZnS microspheres were synthesized via simple, efficient and cost-effective hydrothermal method. The x-ray diffraction study revealed nanocrystalline nature of the synthesized ZnS with the cubic crystal structure. Scanning and transmission electron microscopy observations revealed the formation of 3D microspheres that consist of numerous ZnS nanocrystals. The grown microspheres are also interconnected with each other by driving force of attachment. The obtained product has excellent elemental stoichiometric proportion as evidenced by the EDS technique. The electron diffraction pattern reveals the polycrystalline nature of obtained ZnS product. The band gap was measured from UV-Vis spectroscopic study and found to be blue shifted from the bulk band gap value. The PL study exhibits negligibly weak band edge emission and dominant, widespread defect-related green emission. The nucleation of a ZnS nanocrystals and subsequent growth into the microspheres is also discussed.

  5. Versatile microsphere attachment of GFP-labeled motors and other tagged proteins with preserved functionality

    Directory of Open Access Journals (Sweden)

    Michael Bugiel

    2015-11-01

    Full Text Available Microspheres are often used as handles for protein purification or force spectroscopy. For example, optical tweezers apply forces on trapped particles to which motor proteins are attached. However, even though many attachment strategies exist, procedures are often limited to a particular biomolecule and prone to non-specific protein or surface attachment. Such interactions may lead to loss of protein functionality or microsphere clustering. Here, we describe a versatile coupling procedure for GFP-tagged proteins via a polyethylene glycol linker preserving the functionality of the coupled proteins. The procedure combines well-established protocols, is highly reproducible, reliable, and can be used for a large variety of proteins. The coupling is efficient and can be tuned to the desired microsphere-to-protein ratio. Moreover, microspheres hardly cluster or adhere to surfaces. Furthermore, the procedure can be adapted to different tags providing flexibility and a promising attachment strategy for any tagged protein.

  6. Melatonin Nanoparticles Adsorbed to Polyethylene Glycol Microspheres as Activators of Human Colostrum Macrophages

    International Nuclear Information System (INIS)

    Hara, C.D.C.P.; Honorio-Frana, A.C.; Fagundes, D.L.G.; Guimares, P.C.L.; Franca, E.L.

    2013-01-01

    The effectiveness of hormones associated with polymeric matrices has amplified the possibility of obtaining new drugs to activate the immune system. Melatonin has been reported as an important immunomodulatory agent that can improve many cell activation processes. It is possible that the association of melatonin with polymers could influence its effects on cellular function. Thus, this study verified the adsorption of the hormone melatonin to polyethylene glycol (PEG) microspheres and analyzed its ability to modulate the functional activity of human colostrum phagocytes. Fluorescence microscopy and flow cytometry analyses revealed that melatonin was able to adsorb to the PEG microspheres. This system increased the release of superoxide and intracellular calcium. There was an increase of phagocytic and microbicidal activity by colostrum phagocytes when in the presence of melatonin adsorbed to PEG microspheres. The modified delivery of melatonin adsorbed to PEG microspheres may be an additional mechanism for its microbicidal activity and represents an important potential treatment for gastrointestinal infections of newborns.

  7. Effect of crosslinking agents on chitosan microspheres in controlled release of diclofenac sodium

    Directory of Open Access Journals (Sweden)

    Vanessa L. Gonçalves

    2005-03-01

    Full Text Available In this work chitosan microspheres were prepared by the simple coacervation method and crosslinked using epichlorhydrin or glutaraldehyde for the controlled release of diclofenac sodium. The effects of the crosslinking agents on chitosan microspheres over a 12-hour period were assessed with regard to swelling, hydrolysis, porosity, crosslinking, impregnation of diclofenac sodium (DS, and consequently to the release of DS in buffer solutions, simulating the gastrointestinal tract. The degree of swelling varied with the pH for glutaraldehyde chitosan microspheres (GCM and epichlorhydrin chitosan microspheres (ECM. Partial acid and basic hydrolysis affected the swelling behavior of the GCM matrix. Release kinetics of diclofenac sodium from these matrices were investigated at pH 1.2, 6.8 and 9.0, simulating the gastrointestinal tract conditions. The results indicated that the release mechanism deviated slightly from Fickian transport.

  8. Fabrication of Cerium Oxide and Uranium Oxide Microspheres for Space Nuclear Power Applications

    Energy Technology Data Exchange (ETDEWEB)

    Jeffrey A. Katalenich; Michael R. Hartman; Robert C. O' Brien

    2013-02-01

    Cerium oxide and uranium oxide microspheres are being produced via an internal gelation sol-gel method to investigate alternative fabrication routes for space nuclear fuels. Depleted uranium and non-radioactive cerium are being utilized as surrogates for plutonium-238 (Pu-238) used in radioisotope thermoelectric generators and for enriched uranium required by nuclear thermal rockets. While current methods used to produce Pu-238 fuels at Los Alamos National Laboratory (LANL) involve the generation of fine powders that pose a respiratory hazard and have a propensity to contaminate glove boxes, the sol-gel route allows for the generation of oxide microsphere fuels through an aqueous route. The sol-gel method does not generate fine powders and may require fewer processing steps than the LANL method with less operator handling. High-quality cerium dioxide microspheres have been fabricated in the desired size range and equipment is being prepared to establish a uranium dioxide microsphere production capability.

  9. The development, commercialization, and clinical context of yttrium-90 radiolabeled resin and glass microspheres

    Directory of Open Access Journals (Sweden)

    Mark A. Westcott, MD

    2016-10-01

    Full Text Available Selective internal radiation therapy has emerged as a well-accepted therapeutic for primary and metastatic hepatic malignancies. This therapeutic modality requires the combined efforts of multiple medical disciplines to ensure the safe delivery of yttrium-90 (90Y-labeled microspheres. The development of this therapy followed decades of clinical research involving tumor vascularity and microsphere development. Today, it is essential that treating physicians have a thorough understanding of hepatic tumor vascularity and 90Y microsphere characteristics before undertaking this complex intervention. This review explores the contributions of early investigators of this therapy, as well as the development, US Food and Drug Administration approval, manufacturing process, and attributes of the 2 commercially available 90Y radiolabeled microsphere device to clarify the key physical differences between the products.

  10. A novel approach to preparing magnetic protein microspheres with core-shell structure

    Science.gov (United States)

    Jiang, Wei; Sun, Zhendong; Li, Fengsheng; Chen, Kai; Liu, Tianyu; Liu, Jialing; Zhou, Tianle; Guo, Rui

    2011-03-01

    Magnetic protein microspheres with core-shell structure were prepared through a novel approach based on the sonochemical method and the emulsion solvent evaporation method. The microspheres are composed of the oleic acid and undecylenic acid modified Fe 3O 4 cores and coated with globular bovine serum albumin (BSA). Under an optimized condition, up to 57.8 wt% of approximately 10 nm superparamagnetic Fe 3O 4 nanoparticles could be uniformly encapsulated into the BSA microspheres with the diameter of approximately 160 nm and the high saturation magnetization of 38.5 emu/g, besides of the abundant functional groups. The possible formation mechanism of magnetic microspheres was discussed in detail.

  11. Olive oil DNA fingerprinting by multiplex SNP genotyping on fluorescent microspheres.

    Science.gov (United States)

    Kalogianni, Despina P; Bazakos, Christos; Boutsika, Lemonia M; Targem, Mehdi Ben; Christopoulos, Theodore K; Kalaitzis, Panagiotis; Ioannou, Penelope C

    2015-04-01

    Olive oil cultivar verification is of primary importance for the competitiveness of the product and the protection of consumers and producers from fraudulence. Single-nucleotide polymorphisms (SNPs) have emerged as excellent DNA markers for authenticity testing. This paper reports the first multiplex SNP genotyping assay for olive oil cultivar identification that is performed on a suspension of fluorescence-encoded microspheres. Up to 100 sets of microspheres, with unique "fluorescence signatures", are available. Allele discrimination was accomplished by primer extension reaction. The reaction products were captured via hybridization on the microspheres and analyzed, within seconds, by a flow cytometer. The "fluorescence signature" of each microsphere is assigned to a specific allele, whereas the signal from a reporter fluorophore denotes the presence of the allele. As a model, a panel of three SNPs was chosen that enabled identification of five common Greek olive cultivars (Adramytini, Chondrolia Chalkidikis, Kalamon, Koroneiki, and Valanolia).

  12. Alginate microspheres obtained by the spray drying technique as mucoadhesive carriers of ranitidine

    Directory of Open Access Journals (Sweden)

    Szekalska Marta

    2015-03-01

    Full Text Available The present study is aimed at formulation of alginate (ALG microspheres with ranitidine (RNT by the spray drying method. Obtained microspheres were characterized for particle size, surface morphology, entrapment efficiency, drug loading, in vitro drug release and zeta potential. Mucoadhesive properties were examined by a texture analyser and three types of adhesive layers - gelatine discs, mucin gel and porcine stomach mucosa. Microspheres showed a smooth surface with narrow particle size distribution and RNT loading of up to 70.9 %. All formulations possessed mucoadhesive properties and exhibited prolonged drug release according to the first-order kinetics. DSC reports showed that there was no interaction between RNT and ALG. Designed microspheres can be considered potential carriers of ranitidine with prolonged residence time in the stomach

  13. Alginate microspheres obtained by the spray drying technique as mucoadhesive carriers of ranitidine.

    Science.gov (United States)

    Szekalska, Marta; Amelian, Aleksandra; Winnicka, Katarzyna

    2015-03-01

    The present study is aimed at formulation of alginate (ALG) microspheres with ranitidine (RNT) by the spray drying method. Obtained microspheres were characterized for particle size, surface morphology, entrapment efficiency, drug loading, in vitro drug release and zeta potential. Mucoadhesive properties were examined by a texture analyser and three types of adhesive layers--gelatine discs, mucin gel and porcine stomach mucosa. Microspheres showed a smooth surface with narrow particle size distribution and RNT loading of up to 70.9%. All formulations possessed mucoadhesive properties and exhibited prolonged drug release according to the first-order kinetics. DSC reports showed that there was no interaction between RNT and ALG. Designed microspheres can be considered potential carriers of ranitidine with prolonged residence time in the stomach.

  14. Copper adsorption on magnetite-loaded chitosan microspheres: A kinetic and equilibrium study

    Energy Technology Data Exchange (ETDEWEB)

    Podzus, P.E., E-mail: ppodzus@gmail.com [Grupo de Aplicaciones de Materiales Biocompatibles, Departamento de Quimica, Facultad de Ingenieria, Universidad de Buenos Aires, Paseo Colon 850, C1063ACV Buenos Aires (Argentina); Debandi, M.V. [Grupo de Aplicaciones de Materiales Biocompatibles, Departamento de Quimica, Facultad de Ingenieria, Universidad de Buenos Aires, Paseo Colon 850, C1063ACV Buenos Aires (Argentina); Daraio, M.E., E-mail: medit@fi.uba.ar [Grupo de Aplicaciones de Materiales Biocompatibles, Departamento de Quimica, Facultad de Ingenieria, Universidad de Buenos Aires, Paseo Colon 850, C1063ACV Buenos Aires (Argentina)

    2012-08-15

    A composite of Fe{sub 3}O{sub 4} nanoparticles and the biopolymer chitosan, chemically crosslinked, was prepared as microspheres and used to adsorb copper ions, which were chosen as a model of contaminant metal in water. The adsorption of copper on the magnetic microspheres was studied in a batch process, with different aqueous solutions of Cu (II) at concentrations ranging from 40 to 1100 ppm. Kinetic and equilibrium aspects of the adsorption process were studied. The time-dependent Cu (II) adsorption data were well described by a pseudo-second-order kinetic model. It was found that the equilibrium data follow the Langmuir isotherm, with a maximum adsorption capacity of around 500 mg Cu/g chitosan. The used microspheres were removed and after desorption the material was able to be reused as an adsorbent. The prepared microspheres proved efficient in the removal of copper ions through an adsorption process whose kinetic and equilibrium characteristics were analyzed.

  15. Sustained-release microsphere formulation containing an agrochemical by polyurethane polymerization during an agitation granulation process.

    Science.gov (United States)

    Terada, Takatoshi; Tagami, Manabu; Ohtsubo, Toshiro; Iwao, Yasunori; Noguchi, Shuji; Itai, Shigeru

    2016-07-25

    In this report, a new solventless microencapsulation method by synthesizing polyurethane (PU) from polyol and isocyanate during an agglomeration process in a high-speed mixing apparatus was developed. Clothianidin (CTD), which is a neonicotinoid insecticide and highly effective against a wide variety of insect pests, was used as the model compound. The microencapsulated samples covered with PU (CTD microspheres) had a median diameter of <75μm and sustained-release properties. The CTD microspheres were analyzed by synchrotron X-ray computed tomography measurements. Multiple cores of CTD and other solid excipient were dispersed in PU. Although voids appeared in the CTD microspheres after CTD release, the spherical shape of the microspheres remained stable and no change in its framework was observed. The experimental release data were highly consistent with the Baker-Lonsdale model derived from drug release of spherical monolithic dispersions and consistent with the computed tomography measurements. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Enhanced pharmacokinetics of omeprazole when formulated as gastroretentive microspheres along with piperine

    Directory of Open Access Journals (Sweden)

    Bindu Madhavi Boddupalli

    2014-02-01

    Full Text Available Objective: To investigate the formulation of gastroretentive microspheres of omeprazole along with piperine and estimate the pharmacokinetic parameters in comparison with omeprazole alone. Methods: In our present investigation, gastroretentive microspheres of omeprazole were prepared with the inclusion of piperine. Pharmacokinetic parameters like Cmax, Tmax and area under curve were estimated by administering the prepared microspheres to rabbits and the results were compared with omeprazole alone. Results: There was a significant increase in area under curve from 3.441依1.093 mg·h/mL to 14.422 依0.708 mg·h/mL along with an increase in Cmax. Conclusions: This clearly shows the increased absorption and decreased metabolism of omeprazole when administered along with piperine as gastroretentive microspheres.

  17. Synthesis and electrochemical properties of {alpha}-MnO{sub 2} microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Wang Hongen [College of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China); Zhengzhou Research Institute of CHALCO, Zhengzhou Research Institute of Light Metals, Zhengzhou 450041 (China); Qian Dong [College of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China)], E-mail: qiandong6@yahoo.com.cn

    2008-06-15

    We report the synthesis of {alpha}-MnO{sub 2} microspheres by a low-temperature hydrothermal method involving no templates or catalysts. The products were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy-dispersive X-ray spectrum (EDX), transmission electron microscopy (TEM), Fourier transform infrared spectrum (FT-IR), and Brunauer-Emmett-Teller (BET). The results show that the as-synthesized products are mainly composed of large quantities of {alpha}-MnO{sub 2} microspheres having a sea-urchin shape and a few microspheres constructed of small nanorods. Electrochemical characterization indicates that the resulting {alpha}-MnO{sub 2} microspheres display promising discharge properties than the commercial electrolytic manganese dioxides (EMD) when used as cathodes in alkaline Zn-MnO{sub 2} batteries.

  18. Optimization of Chitosan Microspheres Spray Drying via 32 Full Factorial Design

    Directory of Open Access Journals (Sweden)

    Katsarov Plamen D.

    2017-09-01

    Full Text Available Background: Generally, the preparation of spray-dried microspheres is strongly affected by the process parameters. Particle size and production yield are mainly influenced by the spraying solution concentration and the pump rate of the spray dryer.

  19. Development of alginate microspheres containing thyme essential oil using ionic gelation.

    Science.gov (United States)

    Benavides, Sergio; Cortés, Pablo; Parada, Javier; Franco, Wendy

    2016-08-01

    Essential oils are a good antimicrobial and antioxidant agent alternative in human or animal feed. However, their direct use has several disadvantages such as volatilization or oxidation. The development of essential oil microspheres may help to avoid these problems. The objective of the present research was to microencapsulate thyme essential oil by generating emulsions with different dispersion degrees. The emulsions were encapsulated in calcium-alginate microspheres by ionic gelation. The microspheres were evaluated regarding size, shape, encapsulation efficiency, loading capacity and antimicrobial properties. The results indicate that encapsulation efficiency and loading capacity are dependent on concentration and degree of dispersion. The best encapsulation conditions were obtained at 2% v/v of thyme essential oil with a high dispersion degree (18,000rpm/5min), which was achieved with an efficiency of 85%. Finally, the microspheres obtained showed significant antimicrobial effect, especially in gram-positive bacteria. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. In vitro-in vivo correlation of parenteral risperidone polymeric microspheres.

    Science.gov (United States)

    Shen, Jie; Choi, Stephanie; Qu, Wen; Wang, Yan; Burgess, Diane J

    2015-11-28

    The objective of the present study was to determine whether an in vitro-in vivo correlation (IVIVC) can be established for polymeric microspheres that are equivalent in formulation composition but prepared with different manufacturing processes. Risperidone was chosen as a model therapeutic and poly(lactic-co-glycolic acid) (PLGA) with similar molecular weight as that used in the commercial product Risperdal® Consta® was used to prepare risperidone microspheres. Various manufacturing processes were investigated to produce the risperidone microspheres with similar drug loading (approx. 37%) but distinctly different physicochemical properties (e.g. porosity, particle size and particle size distribution). In vitro release of the risperidone microspheres was investigated using different release testing methods (such as sample-and-separate and USP apparatus 4). In vivo pharmacokinetic profiles of the risperidone microsphere formulations following intramuscular administration were determined using a rabbit model. Furthermore, the obtained pharmacokinetic profiles were deconvoluted using the Loo-Riegelman method and the calculated in vivo release was compared with the in vitro release of these microspheres. Level A IVIVCs were established and validated for the compositionally equivalent risperidone microspheres based on the in vitro release data obtained using USP apparatus 4. The developed IVIVCs demonstrated good predictability and were robust. These results showed that the developed USP apparatus 4 method was capable of discriminating PLGA microspheres that are equivalent in formulation composition but with manufacturing differences and predicting their in vivo performance in the investigated animal model. Copyright © 2015 Elsevier B.V. All rights reserved.