WorldWideScience

Sample records for exchange polymer beads

  1. Fibrous polymer grafted magnetic chitosan beads with strong poly(cation-exchange) groups for single step purification of lysozyme.

    Science.gov (United States)

    Bayramoglu, Gulay; Tekinay, Turgay; Ozalp, V Cengiz; Arica, M Yakup

    2015-05-15

    Lysozyme is an important polypetide used in medical and food applications. We report a novel magnetic strong cation exchange beads for efficient purification of lysozyme from chicken egg white. Magnetic chitosan (MCHT) beads were synthesized via phase inversion method, and then grafted with poly(glycidyl methacrylate) (p(GMA)) via the surface-initiated atom transfer radical polymerization (SI-ATRP). Epoxy groups of the grafted polymer, were modified into strong cation-exchange groups (i.e., sulfonate groups) in the presence of sodium sulfite. The MCTH and MCTH-g-p(GMA)-SO3H beads were characterized by ATR-FTIR, SEM, and VSM. The sulphonate groups content of the modified MCTH-g-p(GMA)-4 beads was found to be 0.53mmolg(-1) of beads by the potentiometric titration method. The MCTH-g-p(GMA)-SO3H beads were first used as an ion-exchange support for adsorption of lysozyme from aqueous solution. The influence of different experimental parameters such as pH, contact time, and temperature on the adsorption process was evaluated. The maximum adsorption capacity was found to be 208.7mgg(-1) beads. Adsorption of lysozyme on the MCTH-g-p(GMA)-SO3H beads fitted to Langmuir isotherm model and followed the pseudo second-order kinetic. More than 93% of the adsorbed lysozyme was desorbed using Na2CO3 solution (pH 11.0). The purity of the lysozyme was checked by HPLC and SDS gel electrophoresis. In addition, the MCTH-g-p(GMA)-SO3H beads prepared in this work showed promising potential for separation of various anionic molecules. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. The defouling of membranes using polymer beads containing ...

    African Journals Online (AJOL)

    This paper reports on an investigation into the possibility of obtaining flux enhancement during the filtration process, as well as the cleaning of membranes, using magnetic polymer beads moving under the influence of an AC magnetic field. Methods, procedures and results for cleaning membranes using magnetic beads, ...

  3. Controlled antiseptic release by alginate polymer films and beads.

    Science.gov (United States)

    Liakos, Ioannis; Rizzello, Loris; Bayer, Ilker S; Pompa, Pier Paolo; Cingolani, Roberto; Athanassiou, Athanassia

    2013-01-30

    Biodegradable polymeric materials based on blending aqueous dispersions of natural polymer sodium alginate (NaAlg) and povidone iodine (PVPI) complex, which allow controlled antiseptic release, are presented. The developed materials are either free standing NaAlg films or Ca(2+)-cross-linked alginate beads, which properly combined with PVPI demonstrate antibacterial and antifungal activity, suitable for therapeutic applications, such as wound dressing. Glycerol was used as the plasticizing agent. Film morphology was studied by optical and atomic force microscopy. It was found that PVPI complex forms well dispersed circular micro-domains within the NaAlg matrix. The beads were fabricated by drop-wise immersion of NaAlg/PVPI/glycerol solutions into aqueous calcium chloride solutions to form calcium alginate beads encapsulating PVPI solution (CaAlg/PVPI). Controlled release of PVPI was possible when the composite films and beads were brought into direct contact with water or with moist media. Bactericidal and fungicidal properties of the materials were tested against Escherichia coli bacteria and Candida albicans fungi. The results indicated very efficient antibacterial and antifungal activity within 48 h. Controlled release of PVPI into open wounds is highly desired in clinical applications to avoid toxic doses of iodine absorption by the wound. A wide variety of applications are envisioned such as external and internal wound dressings with controlled antiseptic release, hygienic and protective packaging films for medical devices, and polymer beads as water disinfectants. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Porous Ceramic Spheres From Cation Exchange Beads

    Science.gov (United States)

    Dynys, Fred

    2005-01-01

    This document is a slide presentation that examines the use of a simple templating process to produce hollow ceramic spheres with a pore size of 1 to 10 microns. Using ion exchange process it was determined that the method produces porous ceramic spheres with a unique structure: (i.e., inner sphere surrounded by an outer sphere.)

  5. Development of polymer-extractant composite beads for separation of radionuclides

    International Nuclear Information System (INIS)

    Kumar, Manmohan; Singh, Krishankant; Bajaj, P.N.

    2009-01-01

    A novel micro porous polymer-extractant composite bead system, containing liquid extractant encapsulated in the core of a polymeric shell, with required porosity and hydrophilicity, to allow exchange of radionuclides without, any significant leaching out of the encapsulated extractant, has been developed for solid-liquid extraction of radionuclides from acidic waste solutions. The reuse of the beads is possible as there is practically no change in its radionuclide extraction efficiency, after repeated extraction second time. The high porosity and hydrophilicity of the synthesized TBP-encapsulated polymeric beads is evident from the presence of ∼ 78% water in the swollen condition. Evaluation of the synthesized beads for extraction of uranium and plutonium from aqueous acidic waste solutions, indicated possibility of their use under the conditions of PUREX process. The aliquate 336-encapsulated polymeric beads showed selective extraction of plutonium from aqueous nitrate solutions in the presence of uranium, and back extraction of the loaded plutonium, using dilute nitric acid or ascorbic acid. (author)

  6. Taste masking of ofloxacin and formation of interpenetrating polymer network beads for sustained release

    Directory of Open Access Journals (Sweden)

    A. Michael Rajesh

    2017-08-01

    Full Text Available The objective of this study was to carry out taste masking of ofloxacin (Ofl by ion exchange resins (IERs followed by sustained release of Ofl by forming interpenetrating polymer network (IPN beads. Drug-resin complexes (DRCs with three different ratios of Ofl to IERs (1:1, 1:2, 1:4 were prepared by batch method and investigated for in vivo and in vitro taste masking. DRC of methacrylic acid-divinyl benzene (MD resin and Ofl prepared at a ratio of 1:4 was used to form IPN beads. IPN beads of MD 1:4 were prepared by following the ionic cross-linking method using sodium carboxymethyl xanthan gum (SCMXG and SCMXG-sodium carboxymethyl cellulose (SCMXG-SCMC. IPN beads were characterized with FT-IR and further studied on sustained release of Ofl at different pH. In vivo taste masking carried out by human volunteers showed that MD 1:4 significantly reduced the bitterness of Ofl. Characterization studies such as FT-IR, DSC, P-XRD and taste masking showed that complex formation took place between drug and resin. In vitro study at gastric pH showed complete release of drug from MD 1:4 within 30 min whereas IPN beads took 5 h at gastric pH and 10 h at salivary pH for the complete release of drug. As the crosslinking increased the release kinetics changed into non-Fickian diffusion to zero-order release mechanism. MD 1:4 showed better performance for the taste masking of Ofl and IPNs beads prepared from it were found useful for the sustained release of Ofl at both the pH, indicating a versatile drug delivery system.

  7. Molecularly imprinted polymer beads for nicotine recognition prepared by RAFT precipitation polymerization: a step forward towards multifunctionalities

    DEFF Research Database (Denmark)

    Zhou, Tongchang; Jørgensen, Lars; Mattebjerg, Maria Ahlm

    2014-01-01

    A nicotine imprinted polymer was synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization using methacrylic acid (MAA) as a functional monomer. The resulting molecularly imprinted polymers were monodispersed beads with an average diameter of 1.55 mm. The molecular...... selectivity of the imprinted polymer beads was evaluated by studying the uptake of nicotine and its structural analogs by the polymer beads. Equilibrium binding results indicate that the amount of nicotine bound to the imprinted polymer beads is significantly higher than that bound to the nonimprinted polymer...

  8. Magnetic polymer beads: Recent trends and developments in synthetic design and applications

    KAUST Repository

    Philippova, Olga

    2011-04-01

    The paper describes the synthesis, properties and applications of magnetic polymer beads. State-of-the-art, future challenges, and promising trends in this field are analyzed. New applications in oil recovery are described. © 2010 Elsevier Ltd. All rights reserved.

  9. “Nanofiltration” Enabled by Super-Absorbent Polymer Beads for Concentrating Microorganisms in Water Samples

    Science.gov (United States)

    Xie, Xing; Bahnemann, Janina; Wang, Siwen; Yang, Yang; Hoffmann, Michael R.

    2016-02-01

    Detection and quantification of pathogens in water is critical for the protection of human health and for drinking water safety and security. When the pathogen concentrations are low, large sample volumes (several liters) are needed to achieve reliable quantitative results. However, most microbial identification methods utilize relatively small sample volumes. As a consequence, a concentration step is often required to detect pathogens in natural waters. Herein, we introduce a novel water sample concentration method based on superabsorbent polymer (SAP) beads. When SAP beads swell with water, small molecules can be sorbed within the beads, but larger particles are excluded and, thus, concentrated in the residual non-sorbed water. To illustrate this approach, millimeter-sized poly(acrylamide-co-itaconic acid) (P(AM-co-IA)) beads are synthesized and successfully applied to concentrate water samples containing two model microorganisms: Escherichia coli and bacteriophage MS2. Experimental results indicate that the size of the water channel within water swollen P(AM-co-IA) hydrogel beads is on the order of several nanometers. The millimeter size coupled with a negative surface charge of the beads are shown to be critical in order to achieve high levels of concentration. This new concentration procedure is very fast, effective, scalable, and low-cost with no need for complex instrumentation.

  10. "Nanofiltration" Enabled by Super-Absorbent Polymer Beads for Concentrating Microorganisms in Water Samples.

    Science.gov (United States)

    Xie, Xing; Bahnemann, Janina; Wang, Siwen; Yang, Yang; Hoffmann, Michael R

    2016-02-15

    Detection and quantification of pathogens in water is critical for the protection of human health and for drinking water safety and security. When the pathogen concentrations are low, large sample volumes (several liters) are needed to achieve reliable quantitative results. However, most microbial identification methods utilize relatively small sample volumes. As a consequence, a concentration step is often required to detect pathogens in natural waters. Herein, we introduce a novel water sample concentration method based on superabsorbent polymer (SAP) beads. When SAP beads swell with water, small molecules can be sorbed within the beads, but larger particles are excluded and, thus, concentrated in the residual non-sorbed water. To illustrate this approach, millimeter-sized poly(acrylamide-co-itaconic acid) (P(AM-co-IA)) beads are synthesized and successfully applied to concentrate water samples containing two model microorganisms: Escherichia coli and bacteriophage MS2. Experimental results indicate that the size of the water channel within water swollen P(AM-co-IA) hydrogel beads is on the order of several nanometers. The millimeter size coupled with a negative surface charge of the beads are shown to be critical in order to achieve high levels of concentration. This new concentration procedure is very fast, effective, scalable, and low-cost with no need for complex instrumentation.

  11. Concentration and separation of trace metals from seawater using a single anion exchange bead

    International Nuclear Information System (INIS)

    Koide, M.; Lee, D.S.; Stallard, M.O.

    1984-01-01

    A technique has been developed for the quantitative adsorption of trace metals onto a single anion exchange bead. The application to the assay of trace metals in seawater was explored with the following radionuclides: 109 Cd, 103 Pd, 192 Ir, 195 Au, 237 Pu, and /sup 99m/Tc. The major ions, Na + , K + , Mg 2+ , and Ca 2+ exist primarily as positively charged species in seawater under nearly all conditions and did not interfere in the adsorption of anionic forms of trace metals onto the single bead. Three types of applications of the technique were investigated: (A) determination of metals in seawater by the direct adsorption onto a single bead without prior concentration, with or without a subsequent desorption from the bead (e.g., Cd, Zn); (B) determination of metals in seawater by the adsorption onto a single bead after a preconcentration step from several liters of seawater (e.g., Pd, Au, Ir), and (C) increasing the yield of Pu and Tc onto a single bead for improved sensitivity in mass spectrometric analyses

  12. Use of an Italian pozzolanic cement for the solidification of bead ion exchange resins

    International Nuclear Information System (INIS)

    De Angelis, G.

    1988-05-01

    Granular ion-exchange resins represent a large portion of the medium-active wastes generated at nuclear power stations. The most common practice for their confinement is to mix them with cement paste and cast the mixture in a concrete shell. Such a procedure however does not prove successful in many cases, because of the extreme swelling to which the embedded resin can give rise. This phenomenon has been investigated carefully. In particular, measurements of the swelling pressure have been made together with evaluation of the volume changes of the resin beads due to ion exchange and of the weight increase as a function of relative humidity. The ion exchange capacity, which continues even after incorporation in the cement matrix has also been put into evidence. The conclusion was drawn that a three component diagram (water - dry resin- cement) has to be prepared every time in order to identify the region corresponding to the better formulations. With this in mind the optimum waste loading of 11.5 wt% of dry resin was chosen to incorporate a mixed bed resin (Amberlite IR 120 Na + and IRA 400 Cl - in the weight ratio of 1:1) into an Italian pozzolanic cement (425 type). Several properties of the final waste form have been investigated, ranging from mechanical (crushing strength, tensile strength, flexural strength, ultrasonic pulse velocity, elastic modulus and Poisson ratio), to thermal stability, radiation stability, permeability, leachability and resistance to bacterial attack. Dimensional stability was also measured with the aim of examining the expansion phenomena which can take place in the presence of resin beads. The data obtained are encouraging for future application of the type 425 cement tested in the field of radwastes. An attempt to explain the performance of this binder, based on its intrinsic properties, was also made. (author)

  13. HIGH ASPECT RATIO ION EXCHANGE RESIN BED - HYDRAULIC RESULTS FOR SPERICAL RESIN BEADS

    International Nuclear Information System (INIS)

    Duignan, M; Charles Nash, C; Timothy Punch, T

    2007-01-01

    A principal role of the DOE Savannah River Site is to safely dispose of a large volume of liquid nuclear waste held in many storage tanks. An in-tank ion exchange unit is being considered for cesium removal to accelerate waste processing. This unit is planned to have a relatively high bed height to diameter ratio (10:1). Complicating the design is the need to cool the ion exchange media; therefore, the ion exchange column will have a central cooling core making the flow path annular. To separate cesium from waste the media being considered is made of resorcinol formaldehyde resin deposited on spherical plastic beads and is a substitute for a previously tested resin made of crystalline silicotitanate. This spherical media not only has an advantage of being mechanically robust, but, unlike its predecessor, it is also reusable, that is, loaded cesium can be removed through elution and regeneration. Resin regeneration leads to more efficient operation and less spent resin waste, but its hydraulic performance in the planned ion exchange column was unknown. Moreover, the recycling process of this spherical resorcinol formaldehyde causes its volume to significantly shrink and swell. To determine the spherical media's hydraulic demand a linearly scaled column was designed and tested. The waste simulant used was prototypic of the wastes' viscosity and density. This paper discusses the hydraulic performance of the media that will be used to assist in the design of a full-scale unit

  14. based anion exchange membrane for alkaline polymer electrolyte

    Indian Academy of Sciences (India)

    Administrator

    Alkaline polymer electrolyte fuel cell; anion exchange membrane; PPO; homogeneous quaterni- zation. 1. Introduction. Presently, alkaline polymer electrolyte fuel cells (APEFCs) using anion exchange membranes have received an immense interest among researchers (Varcoe and Slade. 2005). The advantages of ...

  15. Manipulation of Superparamagnetic Beads on Patterned Exchange-Bias Layer Systems for Biosensing Applications.

    Science.gov (United States)

    Ehresmann, Arno; Koch, Iris; Holzinger, Dennis

    2015-11-13

    A technology platform based on a remotely controlled and stepwise transport of an array arrangement of superparamagnetic beads (SPB) for efficient molecular uptake, delivery and accumulation in the context of highly specific and sensitive analyte molecule detection for the application in lab-on-a-chip devices is presented. The near-surface transport of SPBs is realized via the dynamic transformation of the SPBs' magnetic potential energy landscape above a magnetically stripe patterned Exchange-Bias (EB) thin film layer systems due to the application of sub-mT external magnetic field pulses. In this concept, the SPB velocity is dramatically influenced by the magnitude and gradient of the magnetic field landscape (MFL) above the magnetically stripe patterned EB substrate, the SPB to substrate distance, the magnetic properties of both the SPBs and the EB layer system, respectively, as well as by the properties of the external magnetic field pulses and the surrounding fluid. The focus of this review is laid on the specific MFL design in EB layer systems via light-ion bombardment induced magnetic patterning (IBMP). A numerical approach is introduced for the theoretical description of the MFL in comparison to experimental characterization via scanning Hall probe microscopy. The SPB transport mechanism will be outlined in terms of the dynamic interplay between the EB substrate's MFL and the pulse scheme of the external magnetic field.

  16. Kinetics of polymer adsorption, desorption and exchange

    NARCIS (Netherlands)

    Dijt, J.C.

    1993-01-01

    The aim of the study in this thesis was to gain more insight in the kinetics of polymer adsorption. To this end some well-characterised polymers have been systematically investigated.

    In the process of polymer adsorption one may distinguish three kinetic contributions: transport to

  17. Optimization of methylene blue using Ca(2+) and Zn(2+) bio-polymer hydrogel beads: A comparative study.

    Science.gov (United States)

    Kumar, M; Tamilarasan, R; Arthanareeswaran, G; Ismail, A F

    2015-11-01

    Recently noted that the methylene blue cause severe central nervous system toxicity. It is essential to optimize the methylene blue from aqueous environment. In this study, a comparison of an optimization of methylene blue was investigated by using modified Ca(2+) and Zn(2+) bio-polymer hydrogel beads. A batch mode study was conducted using various parameters like time, dye concentration, bio-polymer dose, pH and process temperature. The isotherms, kinetics, diffusion and thermodynamic studies were performed for feasibility of the optimization process. Freundlich and Langmuir isotherm equations were used for the prediction of isotherm parameters and correlated with dimensionless separation factor (RL). Pseudo-first order and pseudo-second order Lagegren's kinetic equations were used for the correlation of kinetic parameters. Intraparticle diffusion model was employed for diffusion of the optimization process. The Fourier Transform Infrared Spectroscopy (FTIR) shows different absorbent peaks of Ca(2+) and Zn(2+) beads and the morphology of the bio-polymer material analyzed with Scanning Electron Microscope (SEM). The TG & DTA studies show that good thermal stability with less humidity without production of any non-degraded products. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. High Thermal Conductivity Polymer Composites for Low Cost Heat Exchangers

    Energy Technology Data Exchange (ETDEWEB)

    None

    2017-08-01

    This factsheet describes a project that identified and evaluated commercially available and state-of-the-art polymer-based material options for manufacturing industrial and commercial non-metallic heat exchangers. A heat exchanger concept was also developed and its performance evaluated with heat transfer modeling tools.

  19. New anion-exchange polymers for improved separations

    International Nuclear Information System (INIS)

    Jarvinen, G.D.; Barr, M.E.; Marsh, S.F.

    1997-01-01

    Objective is to improve the understanding of how the structure of a new class of anion-exchange polymers controls the binding of anionic actinide complexes from solution. This is needed to develop practical separation systems that will reduce the cost of actinide processing operations within the DOE complex. In addition anion exchange is widely used in industry. Several new series of bifunctional anion- exchange polymers have been designed, synthesized, and tested for removing Pu(IV), Am(III), and U(VI) from nitric acid. The polymers contain a pyridinium site derived from the host poly(4-vinylpyridine) and a second cationic site attached through a chain of 2 to 6 methylene groups. The new polymers removed Pu four to ten times more efficiently than the best commercial materials

  20. Low Cost Polymer heat Exchangers for Condensing Boilers

    Energy Technology Data Exchange (ETDEWEB)

    Butcher, Thomas [Brookhaven National Lab. (BNL), Upton, NY (United States); Trojanowski, Rebecca [Brookhaven National Lab. (BNL), Upton, NY (United States); Wei, George [Brookhaven National Lab. (BNL), Upton, NY (United States); Worek, Michael [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-09-30

    Work in this project sought to develop a suitable design for a low cost, corrosion resistant heat exchanger as part of a high efficiency condensing boiler. Based upon the design parameters and cost analysis several geometries and material options were explored. The project also quantified and demonstrated the durability of the selected polymer/filler composite under expected operating conditions. The core material idea included a polymer matrix with fillers for thermal conductivity improvement. While the work focused on conventional heating oil, this concept could also be applicable to natural gas, low sulfur heating oil, and biodiesel- although these are considered to be less challenging environments. An extruded polymer composite heat exchanger was designed, built, and tested during this project, demonstrating technical feasibility of this corrosion-resistant material approach. In such flue gas-to-air heat exchangers, the controlling resistance to heat transfer is in the gas-side convective layer and not in the tube material. For this reason, the lower thermal conductivity polymer composite heat exchanger can achieve overall heat transfer performance comparable to a metal heat exchanger. However, with the polymer composite, the surface temperature on the gas side will be higher, leading to a lower water vapor condensation rate.

  1. Latent heat storage by silica-coated polymer beads containing organic phase change materials

    Czech Academy of Sciences Publication Activity Database

    Feczkó, T.; Trif, L.; Horák, Daniel

    2016-01-01

    Roč. 132, July (2016), s. 405-414 ISSN 0038-092X R&D Projects: GA MŠk(CZ) LH14318 Institutional support: RVO:61389013 Keywords : latent heat storage * phase change materials * porous beads by suspension polymerization Subject RIV: CD - Macromolecular Chemistry Impact factor: 4.018, year: 2016

  2. Liquid carry-over in an injection moulded all-polymer chip system for immiscible phase magnetic bead-based solid-phase extraction

    International Nuclear Information System (INIS)

    Kistrup, Kasper; Skotte Sørensen, Karen; Wolff, Anders; Fougt Hansen, Mikkel

    2015-01-01

    We present an all-polymer, single-use microfluidic chip system produced by injection moulding and bonded by ultrasonic welding. Both techniques are compatible with low-cost industrial mass-production. The chip is produced for magnetic bead-based solid-phase extraction facilitated by immiscible phase filtration and features passive liquid filling and magnetic bead manipulation using an external magnet. In this work, we determine the system compatibility with various surfactants. Moreover, we quantify the volume of liquid co-transported with magnetic bead clusters from Milli-Q water or a lysis-binding buffer for nucleic acid extraction (0.1 (v/v)% Triton X-100 in 5 M guanidine hydrochloride). A linear relationship was found between the liquid carry-over and mass of magnetic beads used. Interestingly, similar average carry-overs of 1.74(8) nL/µg and 1.72(14) nL/µg were found for Milli-Q water and lysis-binding buffer, respectively. - Highlights: • We present an all-polymer mass producible passive filled microfluidic chip system. • Rapid system fabrication is obtained by injection moulding and ultrasonic welding. • The system is made for single-use nucleic acid extraction using magnetic beads. • We systematically map compatibility of the chip system with various surfactants. • We quantify the volume carry-over of magnetic beads in water and 0.1% triton-X solution

  3. Liquid carry-over in an injection moulded all-polymer chip system for immiscible phase magnetic bead-based solid-phase extraction

    Energy Technology Data Exchange (ETDEWEB)

    Kistrup, Kasper, E-mail: kkis@nanotech.dtu.dk [Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech, Building 345 East, DK-2800 Kongens Lyngby (Denmark); Skotte Sørensen, Karen, E-mail: karen@nanotech.dtu.dk [Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech, Building 345 East, DK-2800 Kongens Lyngby (Denmark); Center for Integrated Point of Care Technologies (CiPoC), DELTA, Venlighedsvej 4, DK-2870 Hørsholm (Denmark); Wolff, Anders, E-mail: anders.wolff@nanotech.dtu.dk [Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech, Building 345 East, DK-2800 Kongens Lyngby (Denmark); Fougt Hansen, Mikkel, E-mail: mikkel.hansen@nanotech.dtu.dk [Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech, Building 345 East, DK-2800 Kongens Lyngby (Denmark)

    2015-04-15

    We present an all-polymer, single-use microfluidic chip system produced by injection moulding and bonded by ultrasonic welding. Both techniques are compatible with low-cost industrial mass-production. The chip is produced for magnetic bead-based solid-phase extraction facilitated by immiscible phase filtration and features passive liquid filling and magnetic bead manipulation using an external magnet. In this work, we determine the system compatibility with various surfactants. Moreover, we quantify the volume of liquid co-transported with magnetic bead clusters from Milli-Q water or a lysis-binding buffer for nucleic acid extraction (0.1 (v/v)% Triton X-100 in 5 M guanidine hydrochloride). A linear relationship was found between the liquid carry-over and mass of magnetic beads used. Interestingly, similar average carry-overs of 1.74(8) nL/µg and 1.72(14) nL/µg were found for Milli-Q water and lysis-binding buffer, respectively. - Highlights: • We present an all-polymer mass producible passive filled microfluidic chip system. • Rapid system fabrication is obtained by injection moulding and ultrasonic welding. • The system is made for single-use nucleic acid extraction using magnetic beads. • We systematically map compatibility of the chip system with various surfactants. • We quantify the volume carry-over of magnetic beads in water and 0.1% triton-X solution.

  4. Strongly nonlinear wave dynamics in a chain of polymer coated beads

    OpenAIRE

    Daraio, C.; Nesterenko, V. F.

    2006-01-01

    Strongly nonlinear phononic crystals were assembled from a chain of Parylene-C coated steel spheres in a polytetrafluoroethylene (PTFE) holder. This system exhibits strongly nonlinear properties and extends the range of materials supporting "sonic vacuum" type behavior. The combination of a high density core and a soft (low elastic modulus) coating ensures a relatively low velocity of wave propagation. The beads contact interaction caused by the deformation of the Parylene coating can be desc...

  5. Development and optimization of water treatment reactors using TiO2-modified polymer beads with a refractive index identical to that of water

    Science.gov (United States)

    Myoga, Arata; Iwashita, Ryutaro; Unno, Noriyuki; Satake, Shin-ichi; Taniguchi, Jun; Yuki, Kazuhisa; Seki, Yohji

    2018-03-01

    Various water purification reactors were constructed using beads of TiO2-coated MEXFLON, which is a fluoropolymer exhibiting a refractive index identical to that of water. The performance of these reactors was evaluated in a recirculation experiment utilizing an aqueous solution of methylene blue. Reactor pipes (length = 150 mm, internal diameter = 10 mm) were made of a fluorinated ethylene polymer with a refractive index of 1.338 and contained 206-bead clusters. A UV lamp was used to irradiate eight reactor pipes surrounding it. The above-mentioned eight bead-packed pipes were connected both in series and in parallel, and the performances of these two reactor types were compared. A pseudo-first-order rate constant of 0.70 h- 1 was obtained for the series connection, whereas the corresponding value for the parallel connection was 1.5 times smaller, confirming the effectiveness of increasing the reaction surface by employing a larger number of beads.

  6. An on-line monitor for cation exchange elution chromatography using lithium silicate glass beads as solid scintillator

    International Nuclear Information System (INIS)

    Zhu Rongbao; Yang Liucheng; Wei Liansheng; Ji Liqiang; Zhang Zengrui

    1988-03-01

    A new type of on-line monitoring system used to monitor radioactive nuclides with α or soft β radiation in the effluent from a high pressure ion exchange column is described. The beads made of cerium-impregnated lithium silicate glass are used as scientillation material. They are filled into a quartz glass tube to form a flow cell. By reducing the diameter of glass beads to more closly approximate the average range of α or soft β radiation in solution, the absolute counting efficiency for 241 Am, 242 Cm α radiation have reached and 85.8% and 92.8% respectively, for 14 C, 90 Sr- 90 Y β radiation, 62.1% and 88.6% respectively. These values can be comparable to those achieved with on-line liquid scientillation technique. When the total amount of 241 Am added into column is decreased to 7.4 Bq it is still possible to obtain a clear chromatography peak (half peak width = 0.22 mL)

  7. A study on dry decontamination using ion exchange polymer

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Ki Jung; Ahn, Byung Gil

    1997-12-01

    Through the project of {sup A} study on dry decontamination using ion exchange polymer{sup ,} the followings were investigated. 1. Highly probable decontamination technologies for the decontamination were investigated. 2. Development of gel type decontamination agent using ion-exchange resin powder (mixed type) as an ion exchanger. 3. Manufacturing of contaminated specimens (5 kinds) with Cs-137 solution and dust / Cs-137 solution. 4. Decontamination performance evaluation of the manufactured agent. 5. Analysis of composition (XRF) and the structure of surface of specimens (optic micrography). (author). 20 refs., 11 figs.

  8. based anion exchange membrane for alkaline polymer electrolyte

    Indian Academy of Sciences (India)

    Administrator

    Abstract. Hydroxyl ion (OH–) conducting anion exchange membranes based on modified poly (phenylene oxide) are fabricated for their application in alkaline polymer electrolyte fuel cells (APEFCs). In the present study, chloromethylation of poly(phenylene oxide) (PPO) is performed by aryl substitution rather than benzyl.

  9. Optimized antimicrobial peptide (Bacitracin) production by immobilized and free cells and of Bacillus Spp GU215 using Wood chips and silicon polymer beads.

    Science.gov (United States)

    Amin, Adnan; Khan, Muhammad Ayaz; Ahmad, Taufeeq

    2013-11-01

    The immobilization of bacillus spp. GU215 on silicon polymer beads, wood chips was performed and antibiotic peptide (bacitracin) production, optimization of parameters were investigated. The immobilized cells presented elevated levels of activity than free cells. The silicon polymer based cells showed widest zones of inhibitions (18mm) in 72 hours and 4% concentration of glucose, PH 8 and 30°C, whereas a marginal decrease in the activity (14mm) was noticed in case of wood chips based immobilization systems and least stable immobilization in 72 hours incubation time, 4% glucose concentration, PH 8 and 30°C. This study illustrates that the silicon polymer based beads facilitate a strong interactions with bacitracin producing cells and render them suitable for excessive and long time production of antibiotic.

  10. The immobilization of anion exchange resins in polymer modified cements

    International Nuclear Information System (INIS)

    Dyer, A.; Morgan, P.D.

    1991-09-01

    Organic anion exchange resins, loaded with 99-Tc as the pertechnate ion, were incorporated into polymer modified cements (Flexocrete Ltd, Preston). BFS/OPC (9:1 mix) also was modified by three polymers from the same source (styrene acrylic (2) styrene butadiene) and loaded with anion exchanger containing the pertechnate. Composites were tested for initial compressive strengths, under water and radiation stability and leach rate. IAEA standard leach testing was with simulated sea and ground waters. Ground water leaching also was carried out on composites subjected to 1.10 9 rads (γ). Leach testing correlated well with compressive strength. Modified composites performed better than the BFS/OPC mix under all conditions studied and were able to encapsulate higher resin loadings. (author)

  11. ION EXCHANGE SUBSTANCES BY SAPONIFICATION OF ALLYL PHOSPHATE POLYMERS

    Science.gov (United States)

    Kennedy, J.

    1959-04-14

    An ion exchange resin having a relatively high adsorption capacity tor uranyl ion as compared with many common cations is reported. The resin comprises an alphyl-allyl hydrogen phosphate polymer, the alphyl group being either allyl or a lower alkyl group having up to 5 carbon atoins. The resin is prepared by polymerizing compounds such as alkyl-diallyl phosphate and triallyl phosphate in the presence of a free radical generating substance and then partially hydrolyzing the resulting polymer to cause partial replacement of organic radicals by cations. A preferred free radical gencrating agent is dibenzoyl peroxide. The partial hydrolysis is brought about by refluxing the polymer with concentrated aqueous NaOH for three or four hours.

  12. Magnetic molecularly imprinted polymer beads prepared by microwave heating for selective enrichment of β-agonists in pork and pig liver samples.

    Science.gov (United States)

    Hu, Yuling; Li, Yuanwen; Liu, Ruijin; Tan, Wei; Li, Gongke

    2011-04-15

    Novel magnetic molecularly imprinted polymer (MIP) beads using ractopamine as template for use in extraction was developed by microwave heating initiated suspension polymerization. Microwave heating, as an alternative heating source, significantly accelerate the polymerization process. By incorporating magnetic iron oxide, superparamagnetic composite MIP beads with average diameter of 80 μm were obtained. The imprinted beads were then characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis and vibrating sample magnetometer. Highly cross-linked porous surface and good magnetic property were observed. The adsorption isotherm modeling was performed by fitting the data to Freundlich isotherm model. The binding sites measured were 3.24 μmol g(-1) and 1.17 μmol g(-1) for the magnetic MIP beads and the corresponding non-imprinted magnetic beads, respectively. Cross-selectivity experiments showed the recognition ability of the magnetic MIP beads to analytes is relative to degree of molecular analogy to the template. Finally, this magnetic MIP bead was successfully used for enrichment of ractopamine, isoxsuprine and fenoterol from ultrasonically extracted solution of pork and pig liver followed by high performance chromatography with fluorescence detection. The proposed method presented good linearity and the detection limits was 0.52-1.04 ng mL(-1).The recoveries were from 82.0% to 90.0% and from 80.4% to 86.8% for the spiked pork and pig liver, respectively, with the RSDs of 5.8-10.0%. Combination of the specific adsorption property of the MIP material and the magnetic separation provided a powerful analytical tool of simplicity, flexibility, and selectivity. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. One pot synthesis of new poly(vinyl alcohol) blended natural polymer based magnetic hydrogel beads: Controlled natural anticancer alkaloid delivery system.

    Science.gov (United States)

    Kesavan, Mookkandi Palsamy; Ayyanaar, Srinivasan; Lenin, Nayagam; Sankarganesh, Murugesan; Dhaveethu Raja, Jeyaraj; Rajesh, Jegathalaprathaban

    2018-02-01

    Facile one-pot synthesis has been demonstrated for new biocompatible and dual responsive magnetic iron oxide nanoparticles cross-linked poly(vinyl alcohol) (PVA) blended natural polymer chitosan (CS) based hydrogel beads (mCS-PVA) as a controlled natural anticancer alkaloid Luotonin A (LuA) delivery system. The prepared magnetic hydrogel beads were characterized using powder X-ray diffraction measurement, Fourier transform-infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, and vibrating sample magnetometer. The magnetic hydrogel beads are exhibited significant water retention and follow the second order kinetic model in swelling study. The swelling ratio of the magnetic gel beads increased by the addition of PVA and showed a maximum swelling ratio of 40.83 ± 1.01 g/g and follows non-Fickian water transport mechanism. Stimuli responsive mCS and mCS-PVA hydrogel beads functionalized with LuA is demonstrated for controlled release at physiological pH and under magnetic field. The magnetic hydrogel beads show highest LuA releasing efficacy at acidic medium (pH = 5.0) with maximum efficiency of 73.33 ± 1.44%. This efficacy may also be tuned by altering the external magnetic field as well as the weight percentage (wt %) of polyethylene glycol. It is clearly that the newly produced magnetic hydrogel beads can be served as an effective intestinal LuA delivery system. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 543-551, 2018. © 2017 Wiley Periodicals, Inc.

  14. Water Soluble Polymers as Proton Exchange Membranes for Fuel Cells

    Directory of Open Access Journals (Sweden)

    Bing-Joe Hwang

    2012-03-01

    Full Text Available The relentless increase in the demand for useable power from energy-hungry economies continues to drive energy-material related research. Fuel cells, as a future potential power source that provide clean-at-the-point-of-use power offer many advantages such as high efficiency, high energy density, quiet operation, and environmental friendliness. Critical to the operation of the fuel cell is the proton exchange membrane (polymer electrolyte membrane responsible for internal proton transport from the anode to the cathode. PEMs have the following requirements: high protonic conductivity, low electronic conductivity, impermeability to fuel gas or liquid, good mechanical toughness in both the dry and hydrated states, and high oxidative and hydrolytic stability in the actual fuel cell environment. Water soluble polymers represent an immensely diverse class of polymers. In this comprehensive review the initial focus is on those members of this group that have attracted publication interest, principally: chitosan, poly (ethylene glycol, poly (vinyl alcohol, poly (vinylpyrrolidone, poly (2-acrylamido-2-methyl-1-propanesulfonic acid and poly (styrene sulfonic acid. The paper then considers in detail the relationship of structure to functionality in the context of polymer blends and polymer based networks together with the effects of membrane crosslinking on IPN and semi IPN architectures. This is followed by a review of pore-filling and other impregnation approaches. Throughout the paper detailed numerical results are given for comparison to today’s state-of-the-art Nafion® based materials.

  15. Broad adsorption of sepsis-related PAMP and DAMP molecules, mycotoxins, and cytokines from whole blood using CytoSorb® sorbent porous polymer beads.

    Directory of Open Access Journals (Sweden)

    Maryann C Gruda

    Full Text Available Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. In sepsis and septic shock, pathogen-associated molecular pattern molecules (PAMPS, such as bacterial exotoxins, cause direct cellular damage and/or trigger an immune response in the host often leading to excessive cytokine production, a maladaptive systemic inflammatory response syndrome response (SIRS, and tissue damage that releases DAMPs, such as activated complement and HMGB-1, into the bloodstream causing further organ injury. Cytokine reduction using extracorporeal blood filtration has been correlated with improvement in survival and clinical outcomes in experimental studies and clinical reports, but the ability of this technology to reduce a broader range of inflammatory mediators has not been well-described. This study quantifies the size-selective adsorption of a wide range of sepsis-related inflammatory bacterial and fungal PAMPs, DAMPs and cytokines, in a single compartment, in vitro whole blood recirculation system.Purified proteins were added to whole blood at clinically relevant concentrations and recirculated through a device filled with CytoSorb® hemoadsorbent polymer beads (CytoSorbents Corporation, USA or control (no bead device in vitro. Except for the TNF-α trimer, hemoadsorption through porous polymer bead devices reduced the levels of a broad spectrum of cytokines, DAMPS, PAMPS and mycotoxins by more than 50 percent.This study demonstrates that CytoSorb® hemoadsorbent polymer beads efficiently remove a broad spectrum of toxic PAMPS and DAMPS from blood providing an additional means of reducing the uncontrolled inflammatory cascade that contributes to a maladaptive SIRS response, organ dysfunction and death in patients with a broad range of life-threatening inflammatory conditions such as sepsis, toxic shock syndrome, necrotizing fasciitis, and other severe inflammatory conditions.

  16. Preparation of Highly Sulfonated Ultra-Thin Proton-Exchange Polymer Membranes for Proton Exchange Membrane Fuel Cells

    Science.gov (United States)

    Jiang, Zhongqing; Meng, Yuedong; Jiang, Zhong-Jie; Shi, Yicai

    Sulfonated ultra-thin proton-exchange polymer membrane carrying pyridine groups was made from a plasma polymerization of styrene, 2-vinylpyridine, and trifluoromethanesulfonic acid by after-glow capacitively coupled discharge technique. Pyridine groups tethered to the polymer backbone acts as a medium through the basic nitrogen for transfer of protons between the sulfonic acid groups of proton exchange membrane. It shows that the method using present technology could effectively depress the degradation of monomers during the plasma polymerization. Spectroscopic analyses reveal that the obtained membranes are highly functionalized with proton exchange groups and have higher proton conductivity. Thus, the membranes are expected to be used in direct methanol fuel cells.

  17. Polymer-filler interactions in poly(vinyl chloride) filled with glass beads : effect of grafted poly(methyl methacrylate)

    NARCIS (Netherlands)

    Boven, Gert; Folkersma, Rudy; Challa, Ger; Schouten, Arend Jan; Bosma, Martin

    1992-01-01

    Adhesion between filler and matrix has been studied using a model system composed of glass bead filled poly(vinyl chloride) (PVC). Stress-strain and volume-strain tests and scanning electron microscopy revealed that adhesion is improved by grafting poly(methyl methacrylate) (PMMA), which is known to

  18. Red Beads and Love Magic. Cross-Cultural Exchanges Between Spain and new Spain in Modern Era

    Directory of Open Access Journals (Sweden)

    Carla Andreia Martins Torres

    2018-01-01

    Full Text Available This paper is about the significance of particular red beads used in love magic during the 17th and 18th centuries, specifically on the construction of symbolic universe through perceptions based on «others» materiality. It aims to provide a connected studied between Spain and New Spain through the histories of the gipsy Generosa Vicente and mestiza Margarita Palacios recovered from the Inquisition authorities notes. This is the way to understand the extent to which cross-cultural contacts privilege the transmission of ideas associated with objects, and how they were used apparently with similar purposes but with a very different meaning.

  19. Preparation of Ca-alginate bio-polymer beads and investigation of their decorporation characteristics for 85Sr, 238U and 234Th by in vitro experiments

    International Nuclear Information System (INIS)

    Gok, C.; Gerstmann, U.; Hoellriegl, V.; Aytas, S.

    2013-01-01

    The aim of this work was to investigate whether Ca-alginate bio-polymer beads (CaABBs) can be used to reduce the bioavailability of radionuclides in the gastrointestinal tract of humans. The uptake of strontium, uranium and thorium from a simulated gastrointestinal system was studied by in vitro techniques using CaABBs. This agent was prepared from Na-alginate through cross-linking with divalent calcium ions according to the egg-box model. The effects of process variables such as pH of the gastrointestinal juice, incubation time and solid-to-solution ratio for the removal of radionuclides from the gastrointestinal juice were investigated. The results suggest that CaABBs are a potent material for reducing the bioavailability of radionuclides with a high uptake efficiency in the gastrointestinal tract.Copy; Author 2012. Published by Oxford Univ. Press. All rights reserved. (authors)

  20. Immobilization of α-amylase and amyloglucosidase onto ion-exchange resin beads and hydrolysis of natural starch at high concentration.

    Science.gov (United States)

    Gupta, Kapish; Jana, Asim Kumar; Kumar, Sandeep; Maiti, Mithu

    2013-11-01

    α-Amylase was immobilized on Dowex MAC-3 with 88 % yield and amyloglucosidase on Amberlite IRA-400 ion-exchange resin beads with 54 % yield by adsorption process. Immobilized enzymes were characterized to measure the kinetic parameters and optimal operational parameters. Optimum substrate concentration and temperature were higher for immobilized enzymes. The thermal stability of the enzymes enhanced after the immobilization. Immobilized enzymes were used in the hydrolysis of the natural starch at high concentration (35 % w/v). The time required for liquefaction of starch to 10 dextrose equivalent (DE) and saccharification of liquefied starch to 96 DE increased. Immobilized enzymes showed the potential for use in starch hydrolysis as done in industry.

  1. Reactivity of the functional groups in functional polymers. Use of T-for-H exchange reaction

    International Nuclear Information System (INIS)

    Imaizumi, Hiroshi; Hasegawa, Shinobu.

    1997-01-01

    In order to reveal the reactivity of several functional polymers, the following two experiments were carried out: observing the hydrogen-isotope exchange reaction (T-for-H exchange reaction) between one of T-labeled functional polymers and 0.500 mol·l -1 aniline dissolved in p-xylene, observing the degree of the T dispersed from the surface area of the polymer under the several conditions. Consequently, the following six matters have been quantitatively obtained. The T-for-H exchange reaction occurred between each T-labeled polymer and aniline, and is more predominant than other chemical reactions within the range of 50-90degC. The reactivity of the polymers are strongly affected by their matrix structures. The degree of the T dispersed from the surface area of each T-labeled polymer is hardly affected by humidity. The higher the temperature is, the larger is the degree of the T dispersed from the surface area. At the same temperature, the degree of the T dispersed from the surface area of each polymer is strongly affected by the physical form of the polymer even if the polymer has the same functional group as the others, and the T existing in the surface area of a T-labeled glassy polymer is less dispersed than that of a porous one. The degree of the T dispersed from the surface area of a T-labeled polymer is small when the degree of the polymerization of the polymer is high. (author)

  2. Coupling sequential injection on-line preconcentration by means of a renewable microcolumn with ion-exchange beads with detection by electrothermal atomic absorption spectrometry. Comparing the performance of eluting the loaded beads with transporting them directly into the graphite tube

    DEFF Research Database (Denmark)

    Wang, Jianhua; Hansen, Elo Harald

    2001-01-01

    The design of a flow injection/sequential injection (FIA/SIA) on-line preconcentration system incorporating a renewable microcolumn with ion-exchange beads and interfaced with an electrothermal atomic absorption spectrometry (ETAAS) detector is described, and its practical applicability.......4% for the procedure in which the loaded beads are transported directly to the graphite furnace for pyrolysis and atomization, and even improved in comparison to the traditional unidirectional and bidirectional repetitive elution procedures which under comparable conditions yield R.S.D.-values of 5.8 and 4...

  3. Polymers application in proton exchange membranes for fuel cells (PEMFCs)

    Science.gov (United States)

    Walkowiak-Kulikowska, Justyna; Wolska, Joanna; Koroniak, Henryk

    2017-07-01

    This review presents the most important research on alternative polymer membranes with ionic groups attached, provides examples of materials with a well-defined chemical structure that are described in the literature. Furthermore, it elaborates on the synthetic methods used for preparing PEMs, the current status of fuel cell technology and its application. It also briefly discusses the development of the PEMFC market.

  4. Investigations on cement/polymer Waste packages containing intermediate level waste and organic exchange resins

    International Nuclear Information System (INIS)

    ELsourougy, M.R.; Zaki, A.A.; Aly, H.F.; Khalil, M.Y.

    1995-01-01

    Polymers can be added to cements to improve its nuclear waste immobilization properties. This trend in cementation processes is attracting attention and requiring through investigations. In this work, polymers of different kinds were added to ordinary portland cement for the purpose of solidifying intermediate level liquid wastes and organic ion exchange resins. Epoxy polymer such as Kemapoxy-150 reduced the leaching rate of cesium compared to cement alone. Latex to cement ratio less than 4% caused an increase in leaching rate of cesium. When cesium was absorbed to an organic resin its leachability was improved. 5 figs., 4 tabs

  5. Effect of chain stiffness and temperature on the dynamics and microstructure of crystallizable bead-spring polymer melts

    Science.gov (United States)

    Nguyen, Hong T.; Hoy, Robert S.

    2016-11-01

    We contrast the dynamics in model unentangled polymer melts of chains of three different stiffnesses: flexible, intermediate, and rodlike. Flexible and rodlike chains, which readily solidify into close-packed crystals (respectively, with randomly oriented and nematically aligned chains), display simple melt dynamics with Arrhenius temperature dependence and a discontinuous change upon solidification. Intermediate-stiffness chains, however, are fragile glass-formers displaying Vogel-Fulcher dynamical arrest, despite the fact that they also possess a nematic-close-packed crystalline ground state. To connect this difference in dynamics to the differing microstructure of the melts, we examine how various measures of structure, including cluster-level metrics recently introduced in studies of colloidal systems, vary with chain stiffness and temperature. No clear static-structural cause of the dynamical arrest is found. However, we find that the intermediate-stiffness chains display qualitatively different dynamical heterogeneity. Specifically, their stringlike motion (cooperative rearrangement) is correlated along chain backbones in a way not found for either flexible or rodlike chains. This activated "crawling" motion is clearly associated with the dynamical arrest observed in these systems, and illustrates one way in which factors controlling the crystallization versus glass formation competition in polymers can depend nonmonotonically on chain stiffness.

  6. Preparation of magnetic indole-3-acetic acid imprinted polymer beads with 4-vinylpyridine and β-cyclodextrin as binary monomer via microwave heating initiated polymerization and their application to trace analysis of auxins in plant tissues.

    Science.gov (United States)

    Zhang, Yi; Li, Yuanwen; Hu, Yuling; Li, Gongke; Chen, Yueqin

    2010-11-19

    Auxin is a crucial phytohormone for precise control of growth and development of plants. Due to its low concentration in plant tissues which are rich in interfering substances, the accurate determination of auxins remains a challenge. In this paper, a new strategy for isolation and enrichment of auxins from plant tissues was obtained by the magnetic molecularly imprinted polymer (mag-MIP) beads, which were prepared by microwave heating initiated suspension polymerization using indole-3-acetic acid (IAA) as template. In order to obtain higher selective recognition cavities, an enhanced imprinting method based on binary functional monomers, 4-vinylpyridine (4-VP) and β-cyclodextrin (β-CD), was adopted for IAA imprinting. The morphological and magnetic characteristics of the mag-MIP beads were characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy and vibrating sample magnetometry. A majority of resultant beads were within the size range of 80-150μm. Porous surface morphology and good magnetic property were observed. Furthermore, the mag-MIP beads fabricated with 4-VP and β-CD as binary functional monomers exhibited improved recognition ability to IAA, as compared with the mag-MIP beads prepared with the individual monomer separately. Competitive rebinding experiment results revealed that the mag-MIP beads exhibited a higher specific recognition for the template than the non-imprinted polymer (mag-NIP) beads. An extraction method by mag-MIP beads coupled with high performance liquid chromatography (HPLC) was developed for determination of IAA and indole-3-butyric acid (IBA) in plant tissues. Linear ranges for IAA and IBA were in the range of 7.00-100.0μgL(-1) and 10.0-100.0μgL(-1), and the detection limits were 3.9 and 7.4μgL(-1), respectively. The analytical performance was also estimated by seedlings or immature embryos samples from three different plant tissues, pea, rice and wheat. Recoveries were in the range of 70

  7. Dynamic diversity of synthetic supramolecular polymers in water as revealed by hydrogen/deuterium exchange

    Science.gov (United States)

    Lou, Xianwen; Lafleur, René P. M.; Leenders, Christianus M. A.; Schoenmakers, Sandra M. C.; Matsumoto, Nicholas M.; Baker, Matthew B.; van Dongen, Joost L. J.; Palmans, Anja R. A.; Meijer, E. W.

    2017-05-01

    Numerous self-assembling molecules have been synthesized aiming at mimicking both the structural and dynamic properties found in living systems. Here we show the application of hydrogen/deuterium exchange (HDX) mass spectrometry (MS) to unravel the nanoscale organization and the structural dynamics of synthetic supramolecular polymers in water. We select benzene-1,3,5-tricarboxamide (BTA) derivatives that self-assemble in H2O to illustrate the strength of this technique for supramolecular polymers. The BTA structure has six exchangeable hydrogen atoms and we follow their exchange as a function of time after diluting the H2O solution with a 100-fold excess of D2O. The kinetic H/D exchange profiles reveal that these supramolecular polymers in water are dynamically diverse; a notion that has previously not been observed using other techniques. In addition, we report that small changes in the molecular structure can be used to control the dynamics of synthetic supramolecular polymers in water.

  8. Optimal target search on a fast-folding polymer chain with volume exchange

    DEFF Research Database (Denmark)

    Lomholt, Michael Andersen; Ambjörnsson, T.; Metzler, R.

    2005-01-01

    We study the search process of a target on a rapidly folding polymer ("DNA") by an ensemble of particles ("proteins"), whose search combines 1D diffusion along the chain, Lévy type diffusion mediated by chain looping, and volume exchange. A rich behavior of the search process is obtained...

  9. Methods for preparing polymer-decorated single exchange-biased magnetic nanoparticles for application in flexible polymer-based films

    Directory of Open Access Journals (Sweden)

    Laurence Ourry

    2017-02-01

    Full Text Available Background: Magnetic nanoparticles (NPs must not only be well-defined in composition, shape and size to exhibit the desired properties (e.g., exchange-bias for thermal stability of the magnetization but also judiciously functionalized to ensure their stability in air and their compatibility with a polymer matrix, in order to avoid aggregation which may seriously affect their physical properties. Dipolar interactions between NPs too close to each other favour a collective magnetic glass state with lower magnetization and coercivity because of inhomogeneous and frustrated macrospin cluster freezing. Consequently, tailoring chemically (through surface functionalization and magnetically stable NPs for technological applications is of primary importance.Results: In this work, well-characterized exchange-biased perfectly epitaxial CoxFe3−xO4@CoO core@shell NPs, which were isotropic in shape and of about 10 nm in diameter, were decorated by two different polymers, poly(methyl methacrylate (PMMA or polystyrene (PS, using radical-controlled polymerization under various processing conditions. We compared the influence of the synthesis parameters on the structural and microstructural properties of the resulting hybrid systems, with special emphasis on significantly reducing their mutual magnetic attraction. For this, we followed two routes: the first one consists of the direct grafting of bromopropionyl ester groups at the surface of the NPs, which were previously recovered and redispersed in a suitable solvent. The second route deals with an “all in solution” process, based on the decoration of NPs by oleic acid followed by ligand exchange with the desired bromopropionyl ester groups. We then built various assemblies of NPs directly on a substrate or suspended in PMMA.Conclusion: The alternative two-step strategy leads to better dispersed polymer-decorated magnetic particles, and the resulting nanohybrids can be considered as valuable building

  10. Unlocking Chain Exchange in Highly Amphiphilic Block Polymer Micellar Systems: Influence of Agitation.

    Science.gov (United States)

    Murphy, Ryan P; Kelley, Elizabeth G; Rogers, Simon A; Sullivan, Millicent O; Epps, Thomas H

    2014-11-18

    Chain exchange between block polymer micelles in highly selective solvents, such as water, is well-known to be arrested under quiescent conditions, yet this work demonstrates that simple agitation methods can induce rapid chain exchange in these solvents. Aqueous solutions containing either pure poly(butadiene- b -ethylene oxide) or pure poly(butadiene- b -ethylene oxide- d 4 ) micelles were combined and then subjected to agitation by vortex mixing, concentric cylinder Couette flow, or nitrogen gas sparging. Subsequently, the extent of chain exchange between micelles was quantified using small angle neutron scattering. Rapid vortex mixing induced chain exchange within minutes, as evidenced by a monotonic decrease in scattered intensity, whereas Couette flow and sparging did not lead to measurable chain exchange over the examined time scale of hours. The linear kinetics with respect to agitation time suggested a surface-limited exchange process at the air-water interface. These findings demonstrate the strong influence of processing conditions on block polymer solution assemblies.

  11. Formulation study on immobilization of spent ion exchange resins in polymer cement

    International Nuclear Information System (INIS)

    Xia Lili; Lin Meiqiong; Bao Liangjin; Fan Xianhua

    2006-01-01

    The aim of this study is to develop a formulation of cement-solidified spent radioactive ion exchange resin form. The solidified form consists of a sort of composite cement, epoxide resin emulsion, and spent ion exchange resins. The composite cement is made up of quick-setting sulphoaluminate cement, silica powder, zeolite, and fly ash in the proportion 1:0.05:0.10:0.05. Sixteen combinations of composite cement, epoxide resin emulsion and mixed anion-cation exchange resins are selected according to a three-factors-four-levels normal design table with the compression strength as the evaluation criterion. The resulted formulation is as follows: the mass ratio of polymer emulsion to composite cement is 0.55:1, the loading of mixed anion-cation exchange resins is 0.3, and the anionic-to-cationic exchange resins ratio is 2:1. The polymer cement solidified forms were tested after 28 d curing for Cs + and Sr 2+ leaching rates, pH and conductivity of the leaching water, and radiation-resistant property in addition to their compressive strength. The measurement results indicate that the performance of thus prepared solidified forms can meet the requirements of the National Standard GB14569.1-93 for near earth's surface disposal of low radioactive waste. (authors)

  12. Desorption of Lipases Immobilized on Octyl-Agarose Beads and Coated with Ionic Polymers after Thermal Inactivation. Stronger Adsorption of Polymers/Unfolded Protein Composites

    Directory of Open Access Journals (Sweden)

    Jose J. Virgen-Ortíz

    2017-01-01

    Full Text Available Lipases from Candida antarctica (isoform B and Rhizomucor miehei (CALB and RML have been immobilized on octyl-agarose (OC and further coated with polyethylenimine (PEI and dextran sulfate (DS. The enzymes just immobilized on OC supports could be easily released from the support using 2% SDS at pH 7, both intact or after thermal inactivation (in fact, after inactivation most enzyme molecules were already desorbed. The coating with PEI and DS greatly reduced the enzyme release during thermal inactivation and improved enzyme stability. However, using OC-CALB/RML-PEI-DS, the full release of the immobilized enzyme to reuse the support required more drastic conditions: a pH value of 3, a buffer concentration over 2 M, and temperatures above 45 °C. However, even these conditions were not able to fully release the thermally inactivated enzyme molecules from the support, being necessary to increase the buffer concentration to 4 M sodium phosphate and decrease the pH to 2.5. The formation of unfolded protein/polymers composites seems to be responsible for this strong interaction between the octyl and some anionic groups of OC supports. The support could be reused five cycles using these conditions with similar loading capacity of the support and stability of the immobilized enzyme.

  13. Porous polymer networks and ion-exchange media and metal-polymer composites made therefrom

    Science.gov (United States)

    Kanatzidis, Mercouri G.; Katsoulidis, Alexandros

    2016-10-18

    Porous polymeric networks and composite materials comprising metal nanoparticles distributed in the polymeric networks are provided. Also provided are methods for using the polymeric networks and the composite materials in liquid- and vapor-phase waste remediation applications. The porous polymeric networks, are highly porous, three-dimensional structures characterized by high surface areas. The polymeric networks comprise polymers polymerized from aldehydes and phenolic molecules.

  14. Immobilisation of spent ion exchange resin in polyester-styrene co-polymer

    International Nuclear Information System (INIS)

    Kumar, Amar

    1999-01-01

    Spent ion exchange resin is generated from primary heat transport system, moderator system and spent fuel storage bay of PHWR which contain large amounts of activated corrosion products and fission products. It was immobilised in crack free monolith of polyester styrene co-polymer. 1.0% of benzoyl peroxide and 0.07% of dimethyl aniline were used as initiator and activator respectively. Gelling time of the polymerisation was 30 minutes. Product has good chemical, mechanical and radiation stability. (author)

  15. Magnetic iron oxide nanoparticles (MIONs) cross-linked natural polymer-based hybrid gel beads: Controlled nano anti-TB drug delivery application.

    Science.gov (United States)

    Kesavan, Mookkandi Palsamy; Ayyanaar, Srinivasan; Vijayakumar, Vijayaparthasarathi; Dhaveethu Raja, Jeyaraj; Annaraj, Jamespandi; Sakthipandi, Kathiresan; Rajesh, Jegathalaprathaban

    2018-04-01

    The nanosized rifampicin (RIF) has been prepared to increase the solubility in aqueous solution, which leads to remarkable enhancement of its bioavailability and their convenient delivery system studied by newly produced nontoxic, biodegradable magnetic iron oxide nanoparticles (MIONs) cross-linked polyethylene glycol hybrid chitosan (mCS-PEG) gel beads. The functionalization of both nano RIF and mCS-PEG gel beads were studied using various spectroscopic and microscopic techniques. The size of prepared nano RIF was found to be 70.20 ± 3.50 nm. The mechanical stability and swelling ratio of the magnetic gel beads increased by the addition of PEG with a maximum swelling ratio of 38.67 ± 0.29 g/g. Interestingly, this magnetic gel bead has dual responsive assets in the nano drug delivery application (pH and the magnetic field). As we expected, magnetic gel beads show higher nano drug releasing efficacy at acidic medium (pH = 5.0) with maximum efficiency of 71.00 ± 0.87%. This efficacy may also be tuned by altering the external magnetic field and the weight percentage (wt%) of PEG. These results suggest that such a dual responsive magnetic gel beads can be used as a potential system in the nano drug delivery applications. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1039-1050, 2018. © 2017 Wiley Periodicals, Inc.

  16. Liquid carry-over in an injection moulded all-polymer chip system for immiscible phase magnetic bead-based solid-phase extraction

    DEFF Research Database (Denmark)

    Kistrup, Kasper; Sørensen, Karen Skotte; Wolff, Anders

    2014-01-01

    -binding buffer for nucleic acid extraction (0.1 (v/v)% Triton X-100 in 5 M guanidine hydrochloride). A linear relationship was found between the liquid carry-over and mass of magnetic beads used. Interestingly, similar average carry-overs of 1.74(8) nL/µg and 1.72(14) nL/µg were found for Milli-Q water and lysis...... phase filtration and features passive liquid filling and magnetic bead manipulation using an external magnet. In this work, we determine the system compatibility with various surfactants. Moreover, we quantify the volume of liquid co-transported with magnetic bead clusters from Milli-Q water or a lysis...

  17. Communication: Self-assembly of a model supramolecular polymer studied by replica exchange with solute tempering

    Science.gov (United States)

    Arefi, Hadi H.; Yamamoto, Takeshi

    2017-12-01

    Conventional molecular-dynamics (cMD) simulation has a well-known limitation in accessible time and length scales, and thus various enhanced sampling techniques have been proposed to alleviate the problem. In this paper, we explore the utility of replica exchange with solute tempering (REST) (i.e., a variant of Hamiltonian replica exchange methods) to simulate the self-assembly of a supramolecular polymer in explicit solvent and compare the performance with temperature-based replica exchange MD (T-REMD) as well as cMD. As a test system, we consider a relatively simple all-atom model of supramolecular polymerization (namely, benzene-1,3,5-tricarboxamides in methylcyclohexane solvent). Our results show that both REST and T-REMD are able to predict highly ordered polymer structures with helical H-bonding patterns, in contrast to cMD which completely fails to obtain such a structure for the present model. At the same time, we have also experienced some technical challenge (i.e., aggregation-dispersion transition and the resulting bottleneck for replica traversal), which is illustrated numerically. Since the computational cost of REST scales more moderately than T-REMD, we expect that REST will be useful for studying the self-assembly of larger systems in solution with enhanced rearrangement of monomers.

  18. Alkaline degradation studies of anion exchange polymers to enable new membrane designs

    Science.gov (United States)

    Nunez, Sean Andrew

    Current performance targets for anion-exchange membrane (AEM) fuel cells call for greater than 95% alkaline stability for 5000 hours at temperatures up to 120 °C. Using this target temperature of 120 °C, an incisive 1H NMR-based alkaline degradation method to identify the degradation products of n-alkyl spacer tetraalkylammonium cations in various AEM polymers and small molecule analogs. Herein, the degradation mechanisms and rates of benzyltrimethylammonium-, n-alkyl interstitial spacer- and n-alkyl terminal pendant-cations are studied on several architectures. These findings demonstrate that benzyltrimethylammonium- and n-alkyl terminal pendant cations are more labile than an n-alkyl interstitial spacer cation and conclude that Hofmann elimination is not the predominant mechanism of alkaline degradation. Additionally, the alkaline stability of an n-alkyl interstitial spacer cation is enhanced when combined with an n-alkyl terminal pendant. Interestingly, at 120 °C, an inverse trend was found in the overall alkaline stability of AEM poly(styrene) and AEM poly(phenylene oxide) samples than was previously shown at 80 °C. Successive small molecule studies suggest that at 120 °C, an anion-induced 1,4-elimination degradation mechanism may be activated on styrenic AEM polymers bearing an acidic alpha-hydrogen. In addition, an ATR-FTIR based method was developed to assess the alkaline stability of solid membranes and any added resistance to degradation that may be due to differential solubilities and phase separation. To increase the stability of anion exchange membranes, Oshima magnesate--halogen exchange was demonstrated as a method for the synthesis of new anion exchange membranes that typically fail in the presence of organolithium or Grignard reagents alone. This new chemistry, applied to non-resinous polymers for the first time, proved effective for the n-akyl interstitial spacer functionalization of poly(phenylene oxide) and poly(styrene- co

  19. Effect of algal density in bead, bead size and bead concentrations ...

    African Journals Online (AJOL)

    Effect of algal density in bead, bead size and bead concentrations on wastewater nutrient removal. ... African Journal of Biotechnology ... The bioreactor containing algal beads (4 mm diameter) with 1.5 x 106 cells bead-1 (cell stocking) at concentration of 10.66 beads ml-1 wastewater (1:3 bead: wastewater, v/v) achieved ...

  20. Final Report for Project titled High Thermal Conductivity Polymer Composites for Low-Cost Heat Exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Thibaud-Erkey, Catherine [United Technologies reserach Center, East Hartford, CT (United States); Alahyari, Abbas [United Technologies reserach Center, East Hartford, CT (United States)

    2016-12-28

    Heat exchangers (HXs) are critical components in a wide range of heat transfer applications, from HVAC (Heating Ventilation and Cooling) to automobiles to manufacturing plants. They require materials capable of transferring heat at high rates while also minimizing thermal expansion over the usage temperature range. Conventionally, metals are used for applications where effective and efficient heat exchange is required, since many metals exhibit thermal conductivity over 100 W/m K. While metal HXs are constantly being improved, they still have some inherent drawbacks due to their metal construction, in particular corrosion. Polymeric material can offer solution to such durability issues and allow designs that cannot be afforded by metal construction either due to complexity or cost. A major drawback of polymeric material is their low thermal conductivity (0.1-0.5? W/mK) that would lead to large system size. Recent improvements in the area of filled polymers have highlighted the possibility to greatly improve the thermal conductivity of polymeric materials while retaining their inherent manufacturing advantage, and have been applied to heat sink applications. Therefore, the objective of this project was to develop a robust review of materials for the manufacturing of industrial and commercial non-metallic heat exchangers. This review consisted of material identification, literature evaluation, as well as empirical and model characterization, resulting in a database of relevant material properties and characteristics to provide guidance for future heat exchanger development.

  1. Mass and Heat Transfer in Ion-Exchange Membranes Applicable to Solid Polymer Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Otteroey, M.

    1996-04-01

    In this doctoral thesis, an improved emf method for determination of transference numbers of two counter ions in ion-exchange membranes is presented. Transference numbers were obtained as a continuous function of the composition. The method avoids problems with diffusion by using a stack of membranes. Water transference coefficients in ion-exchange membranes is discussed and reversible and irreversible water transfer is studied by emf methods. Efforts were made to get data relevant to the solid polymer fuel cell. The results support the findings of other researchers that the reversible water transfer is lower than earlier predicted. A chapter on the conductivity of ion-exchange membranes establishes a method to separate the very thin liquid layers surrounding the membranes in a stack. Using the method it was found that the conductivity is obtained with high accuracy and that the liquid layer in a membrane stack can contribute significantly to the total measured resistance. A four point impedance method was tested to measure the conductivity of membranes under fuel cell conditions. Finally, there is a discussion of reversible heat effects and heat transfer in ion-exchange membranes. 155 refs., 45 figs., 13 tabs.

  2. Efficacy of polymer coating of probiotic beads suspended in pressurized and pasteurized longan juices on the exposure to simulated gastrointestinal environment.

    Science.gov (United States)

    Chaikham, Pittaya; Apichartsrangkoon, Arunee; George, Trevor; Jirarattanarangsri, Wachira

    2013-11-01

    Alginate-coated Lactobacillus acidophilus LA5 or Lactobacillus casei 01 was recoated with either 0.1-0.5% (w/v) alginate or 0.05-0.15% (w/v) poly-L-lysine (PLL) plus 0.2% (w/v) alginate or 5-15% (w/v) gelatin, after which they were determined for survivability in gastric or bile longan juices. The morphology of encapsulated probiotic cells illustrated that recoated beads with 0.5% alginate showed a more compact surface and a greater protective effect than other recoating materials. The recoated beads with 0.5% alginate and 0.05-0.15% PLL plus 0.2% alginate of both strains showed the highest viability in gastric longan juice. In bile longan juice, only 0.5% alginate showed the best protection for both recoated beads. When considering the storage stability, encapsulated L. acidophilus LA5 exhibited a higher viable count than those of the free cells, whereas L. casei 01 showed equivalent viability of both free and double-coated cells. Based on the impact of pressurization or pasteurization, both processed juices gave rise to equivalent survivability of the probiotic cells during storage.

  3. The control of beads diameter of bead-on-string electrospun nanofibers and the corresponding release behaviors of embedded drugs.

    Science.gov (United States)

    Li, Tingxiao; Ding, Xin; Tian, Lingling; Hu, Jiyong; Yang, Xudong; Ramakrishna, Seeram

    2017-05-01

    Bead-on-string nanofibers, with appropriate control of the beads diameter, are potential fibrous structures for efficient encapsulation of particle drugs in micron scales and could achieve controlled drug release for tissue engineering applications. In this study, the beads diameter of electrospun bead-on-string nanofibers was controlled by adjusting the concentration of spinning polymer, poly (lactic-co-glycolic acid) (PLGA), and the solvent ratio of chloroform to acetone. The images of the scanning electron microscopy (SEM) suggested that bead-on-string nanofibers could be successfully obtained only with a certain range of PLGA solution concentration. Moreover, with the decrease in the solvent ratio of chloroform to acetone, the range was left-shifted towards a smaller concentration. In addition, increase in the PLGA solution concentration within the range the beads diameter became greater and the shape of the beads changed from oval to slender when increasing the PLGA concentration within the range. The bead-on-string nanofibers with different beads diameter were further used to load micro-particle drugs of tetracycline hydrochloride, as a model drug, to examine the release behavior of nanofibers scaffold. The release profiles of drug loaded bead-on-string nanofibers demonstrated the possibility to alleviate the burst drug release by means of beads diameter control. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. The role of polymer nanolayer architecture on the separation performance of anion-exchange membrane adsorbers: I. Protein separations.

    Science.gov (United States)

    Bhut, Bharat V; Weaver, Justin; Carter, Andrew R; Wickramasinghe, S Ranil; Husson, Scott M

    2011-11-01

    This contribution describes the preparation of strong anion-exchange membranes with higher protein binding capacities than the best commercial resins. Quaternary amine (Q-type) anion-exchange membranes were prepared by grafting polyelectrolyte nanolayers from the surfaces of macroporous membrane supports. A focus of this study was to better understand the role of polymer nanolayer architecture on protein binding. Membranes were prepared with different polymer chain graft densities using a newly developed surface-initiated polymerization protocol designed to provide uniform and variable chain spacing. Bovine serum albumin and immunoglobulin G were used to measure binding capacities of proteins with different size. Dynamic binding capacities of IgG were measured to evaluate the impact of polymer chain density on the accessibility of large size protein to binding sites within the polyelectrolyte nanolayer under flow conditions. The dynamic binding capacity of IgG increased nearly linearly with increasing polymer chain density, which suggests that the spacing between polymer chains is sufficient for IgG to access binding sites all along the grafted polymer chains. Furthermore, the high dynamic binding capacity of IgG (>130 mg/mL) was independent of linear flow velocity, which suggests that the mass transfer of IgG molecules to the binding sites occurs primarily via convection. Overall, this research provides clear evidence that the dynamic binding capacities of large biologics can be higher for well-designed macroporous membrane adsorbers than commercial membrane or resin ion-exchange products. Specifically, using controlled polymerization leads to anion-exchange membrane adsorbers with high binding capacities that are independent of flow rate, enabling high throughput. Results of this work should help to accelerate the broader implementation of membrane adsorbers in bioprocess purification steps. Copyright © 2011 Wiley Periodicals, Inc.

  5. Diclofenac removal in urine using strong-base anion exchange polymer resins.

    Science.gov (United States)

    Landry, Kelly A; Boyer, Treavor H

    2013-11-01

    One of the major sources of pharmaceuticals in the environment is wastewater effluent of which human urine contributes the majority of pharmaceuticals. Urine source separation has the potential to isolate pharmaceuticals at a higher concentration for efficient removal as well as produce a nutrient byproduct. This research investigated the efficacy of using strong-base anion exchange polymer resins to remove the widely detected and abundant pharmaceutical, diclofenac, from synthetic human urine under fresh and ureolyzed conditions. The majority of experiments were conducted using a strong-base, macroporous, polystyrene resin (Purolite A520E). Ion-exchange followed a two-step removal rate with rapid removal in 1 h and equilibrium removal in 24 h. Diclofenac removal was >90% at a resin dose of 8 mL/L in both fresh and ureolyzed urine. Sorption of diclofenac onto A520E resin was concurrent with desorption of an equivalent amount of chloride, which indicates the ion-exchange mechanism is occurring. The presence of competing ions such as phosphate and citrate did not significantly impact diclofenac removal. Comparisons of three polystyrene resins (A520E, Dowex 22, Dowex Marathon 11) as well as one polyacrylic resin (IRA958) were conducted to determine the major interactions between anion exchange resin and diclofenac. The results showed that polystyrene resins provide the highest level of diclofenac removal due to electrostatic interactions between quaternary ammonium functional groups of resin and carboxylic acid of diclofenac and non-electrostatic interactions between resin matrix and benzene rings of diclofenac. Diclofenac was effectively desorbed from A520E resin using a regeneration solution that contained 4.5% (m/m) NaCl in an equal-volume mixture of methanol and water. The greater regeneration efficiency of the NaCl/methanol-water mixture over the aqueous NaCl solution supports the importance of non-electrostatic interactions between resin matrix and benzene rings

  6. Sulfonation Process and Desalination Effect of Polystyrene/PVDF Semi-Interpenetrating Polymer Network Cation Exchange Membrane

    Directory of Open Access Journals (Sweden)

    Yin-lin Lei

    2014-07-01

    Full Text Available With the classical sulfonation method of polystyrene-based strongly acidic cation exchange resins, polystyrene/polyvinylidene fluoride (PVDF alloy particles were sulfonated to obtain a cation exchange resin, which was then directly thermoformed to prepare a semi-interpenetrating polymer network (semi-IPN cation exchange membrane. The effects of the swelling agent, sulfonation time and temperature and the relative contents of polystyrene and divinylbenzene (DVB in the alloy particles on the feasibility of the membrane formation are discussed. The results indicate that a favorable sulfonation degree above 80% and a suitable ion exchange capacity of 1.5–2.4 mmol/g can be gained, with concentrated sulfuric acid as the sulfonation agent and 1,2-dichloroethane as the swelling agent. The running electrical resistance and desalination effect of the prepared cation exchange membrane were measured in a pilot-scale electrodialyser and not only obviously exceeded a commercial heterogeneous cation exchange membrane, but was also very close to a commercial homogenous membrane. In this way, the authors have combined the classical sulfonation method of polystyrene-based cation exchange resins with the traditional thermoforming manufacturing process of heterogeneous cation exchange membranes, to successfully develop a novel, low-price, but relatively high-performance polystyrene/PVDF cation exchange membrane with the semi-IPN structure.

  7. A Magnetic Bead Actuator

    NARCIS (Netherlands)

    Derks, R.; Prins, M.W.J.; Wimberger-Friedl, R.

    2006-01-01

    Actuation principles of superparamagnetic beads applicable on biosensing (at single beads and chain orderning) are studied in this report. This research can be used to develop new techniques that are able to accelerate bio-assays. An experimental setup containing a sub-microliter fluid volume

  8. Electrical and thermal conductivities of novel metal mesh hybrid polymer composite bipolar plates for proton exchange membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Hsiao, Min-Chien; Liao, Shu-Hang; Yen, Ming-Yu.; Ma, Chen-Chi M. [Department of Chemical Engineering, National Tsing Hua University, 101, Section 2 Kuang Fu Road, Hsin-Chu 30043 (China); Lee, Shuo-Jen; Chen, Yung-Hung [Fuel Cell Center, Yuan Ze University, Tao-Yuan 32003 (China); Hung, Chih-Hung [Plastics Industry Development Center, Tai-Chung 40768 (China); Lin, Yu-Feng [Chemicals and Chemical Engineering, Chung Shan Institute of Science and Technology, Taoyuan 325 (China); Xie, Xiao-Feng [Institute of Nuclear and New Energy technology, Tsinghua University, Beijing 100084 (China)

    2010-01-15

    This study prepares novel metal mesh hybrid polymer composite bipolar plates for proton exchange membrane fuel cells (PEMFCs) via inserting a copper or aluminum mesh in polymer composites. The composition of polymer composites consists of 70 wt% graphite powder and 0-2 wt% modified multi-walled carbon nanotubes (m-MWCNTs). Results indicate that the in-plane electrical conductivity of m-MWCNTs/polymer composite bipolar plates increased from 156 S cm{sup -1} (0 wt% MWCNT) to 643 S cm{sup -1} (with 1 wt% MWCNT) (D.O.E. target >100 S cm{sup -1}). The bulk thermal conductivities of the copper and aluminum mesh hybrid polymer composite bipolar plates (abbreviated to Cu-HPBP and Al-HPBP) increase from 27.2 W m{sup -1} K{sup -1} to 30.0 W m{sup -1} K{sup -1} and 30.4 W m{sup -1} K{sup -1}, respectively. The through-plane conductivities decrease from 37.8 S cm{sup -1} to 36.7 S cm{sup -1} for Cu-HPBP and 22.9 S cm{sup -1} for Al-HPBP. Furthermore, the current and power densities of a single fuel cell using copper or aluminum mesh hybrid polymer composite bipolar plates are more stable than that of using neat polymer composite bipolar plates, especially in the ohmic overpotential region of the polarization curves of single fuel cell tests. The overall performance confirms that the metal mesh hybrid polymer composite bipolar plates prepared in this study are promising for PEMFC application. (author)

  9. Effect of algal density in bead, bead size and bead concentrations ...

    African Journals Online (AJOL)

    Laboratory experiments were performed to study nitrogen and phosphorus uptake by the unicellular green microalga Chlorella vulgaris immobilized in calcium alginate beads. Different cell stockings in beads, different bead sizes and different algal bead concentrations in wastewaters were tested. Significant higher nutrients ...

  10. Biodegradation of ion-exchange media

    International Nuclear Information System (INIS)

    Bowerman, B.S.; Clinton, J.H.; Cowdery, S.R.

    1988-08-01

    Ion-exchange media, both bead resins and powdered filter media, are used in nuclear power plants to remove radioactivity from process water prior to reuse or environmental discharge. Since the ion- exchange media are made from synthetic hydrocarbon-based polymers, they may be susceptible to damage from biological activity. The purpose of this study was to investigate some of the more basic aspects of biodegradation of ion-exchange media, specifically to evaluate the ability of microorganisms to utilize the ion-exchange media or materials sorbed on them as a food source. The ASTM-G22 test, alone and combined with the Bartha Pramer respirometric method, failed to indicate the biodegradability of the ion-exchange media. The limitation of these methods was that they used a single test organism. In later phases of this study, a mixed microbial culture was grown from resin waste samples obtained from the BNL High Flux Beam Reactor. These microorganisms were used to evaluate the susceptibility of different types of ion-exchange media to biological attack. Qualitative assessments of biodegradability were based on visual observations of culture growths. Greater susceptibility was associated with increased turbidity in solution indicative of bacterial growth, and more luxuriant fungal mycelial growth in solution or directly on the ion-exchange resin beads. 21 refs., 9 figs., 18 tabs

  11. Synthesis of highly branched sulfonated polymers and the effects of degree of branching on properties of branched sulfonated polymers as proton exchange membranes

    Science.gov (United States)

    Xie, Huixiong; Wang, Duan; Tao, Dan; Wang, Lei

    2014-09-01

    Branched sulfonated polymers exhibit excellent properties as proton exchange membranes (PEMs). However, very few highly branched sulfonated polymers are reported as PEMs. The highly branched polymer, including the method to increase degree of branching (DB) and the effects of DB on the properties of PEMs, should be further studied. In this work, novel branched sulfonated poly(fluorenyl ether ketone sulfone)s with different DB value are synthesized by direct polycondensation reactions from bisphenol fluorene (A2), sulfonated 4,4‧-difluorobenzphenone, 1,3,5-tris(4-(4-fluorophenylsulfonyl)phenyl)benzene (B3-3) and 4,4‧-difluorodiphenyl sulfone. The highest DB with 10% branching agent is obtained using the B3-3 monomer. The method to increase the DB is discussed. It is found that B3 scaffold with long and hard arms can effectively increase the DB value. The effects of DB on the properties, including oxidative stability, proton conductivity, water uptake, swelling ratio, thermal stability, mechanical property and microstructure, are investigated. With increasing DB value, oxidative stability and proton conductivity of the membranes increase remarkably, but swelling ratio and tensile strength decrease slowly. The membrane with the highest DB value (10%) exhibits high proton conductivity (0.42 S cm-1) and oxidative stability (327 min), as well as relatively low swelling ratio (16.2%) at 80 °C.

  12. Half bead welding technique

    International Nuclear Information System (INIS)

    Canonico, D.A.; Holz, P.P.

    1978-05-01

    The ORNL has employed the Section XI half-bead procedure for six repair welds. Table 2 identifies the repairs and the components upon which they were accomplished. The weld repairs were performed to permit us to evaluate material properties, residual stresses, weld repair procedures, and structural behavior of repaired pressure vessels. As a consequence of our study we concluded that when the half bead procedure is correctly applied: (1) there is no metallurgical degradation of the base material, (2) residual stresses of yield point magnitude will be present, and (3) the structural integrity of the pressure vessel is not impaired at Charpy V-notch upper shelf temperatures

  13. Échangeurs à condensation en matériau polymère Condensation Heat Exchangers Made of Polymer Material

    Directory of Open Access Journals (Sweden)

    Grehier A.

    2006-11-01

    Full Text Available L'échangeur gaz-gaz en matériau polymère, développé conjointement par la Société d'Équipements Thermiques et de Récupérateurs Métalliques (SETREM et l'Institut Français du Pétrole (IFP, fait ici l'objet d'une description de son principe de base et des méthodes de modélisation développées par I'IFP. Le caractère modulaire de sa conception et les avantages spécifiques des matériaux polymères (inertie chimique, mise en oeuvre aisée, non adhérence des salissures, légèreté constituent les principaux arguments des développements potentiels de cet échangeur. Parmi ceux-ci figure la récupération sur fumées de chaudière alimentée en fuel lourd n°2 dont l'intérêt a été démontré sur un prototype essayé au Centre d'Études et de Développement Industriels de I'IFP. Il est également fait état de la première application effective de cet échangeur pour la déshumidification des fumées issues de chaudières à gaz à condensation. On évite ainsi le tubage des conduits de fumées qui constitue un obstacle économique majeur à la diffusion de telles installations en chauffage collectif. Sont présentées enfin les caractéristiques d'un échangeur de ce type (surface d'échange : environ 5000 m² assurant le séchage d'air humide dans une application du secteur agroalimentaire en cours de projet. The gas-gas heat exchanger made of polymer material, developed jointly by Société d'Equipements Thermiques et de Récupérateurs Métalliques (SETREM and the Institut Français du Pétrole, (IFP, is described here in its basic principle together with the modeling methods developed by IFP. The modular nature of its design and the specific advantages of polymer materials (chemical inertia, ease of implementation, nonadherence of fouling, lightness make up the principal arguments for the potential development of this heat exchanger. Among these arguments is heat recovery from the flue gas from a furnace fired by No. 2 heavy

  14. Olefin metathesis for effective polymer healing via dynamic exchange of strong carbon-carbon bonds

    Science.gov (United States)

    Guan, Zhibin; Lu, Yixuan

    2015-09-15

    A method of preparing a malleable and/or self-healing polymeric or composite material is provided. The method includes providing a polymeric or composite material comprising at least one alkene-containing polymer, combining the polymer with at least one homogeneous or heterogeneous transition metal olefin metathesis catalyst to form a polymeric or composite material, and performing an olefin metathesis reaction on the polymer so as to form reversible carbon-carbon double bonds in the polymer. Also provided is a method of healing a fractured surface of a polymeric material. The method includes bringing a fractured surface of a first polymeric material into contact with a second polymeric material, and performing an olefin metathesis reaction in the presence of a transition metal olefin metathesis catalyst such that the first polymeric material forms reversible carbon-carbon double bonds with the second polymeric material. Compositions comprising malleable and/or self-healing polymeric or composite material are also provided.

  15. Sequential tentacle grafting and charge modification for enhancing charge density of mono-sized beads for facilitated protein refolding and purification from inclusion bodies.

    Science.gov (United States)

    Dong, Xiao-Yan; Chen, Ran; Yang, Chun-Yan; Sun, Yan

    2014-06-20

    We have previously found that addition of like-charged media in a refolding solution can greatly enhance the refolding of pure proteins by suppressing protein aggregation. Herein, negatively charged mono-sized microspheres with sulfonic groups were fabricated to explore the facilitating effect of like-charged media on the refolding of enhanced green fluorescent protein (EGFP) expressed as inclusion bodies (IBs). A sequential polymer-tentacle grafting and sulfonate modification strategy was developed to increase the charge density of mono-sized poly(glycidyl methacrylate) (pGMA) beads (2.4μm). Namely, GMA was first grafted onto the beads by grafting polymerization to form poly(GMA) tentacles on the pGMA beads, and then the epoxy groups on the tentacles were converted into sulfonic groups by modification with sodium sulfite. By this fabrication strategy, the charge density of the beads reached 793μmol/g, about 2.8 times higher than that modified without prior grafting of the pGMA beads (285μmol/g). The negatively charged beads of different charge densities were used for facilitating the refolding of like-charged EGFP from IBs. The refolding yield as well as refolding rate increased with increasing charge density. The anti-aggregation effects of urea and like-charged microspheres were synergetic. In addition, partial purification of EGFP was achieved because the ion-exchange adsorption led to 52% removal of positively charged contaminant proteins in the refolded solution. Finally, reusability of the tentacle beads was demonstrated by repetitive EGFP refolding and recovery cycles. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Development of sustained release fast-disintegrating tablets using various polymer-coated ion-exchange resin complexes.

    Science.gov (United States)

    Jeong, Seong Hoon; Park, Kinam

    2008-04-02

    Complex formation between drugs and ion-exchange resins was investigated and the effects of coating by various aqueous polymeric dispersions on the complexes were evaluated for developing new sustained-release fast-disintegrating tablets (FDTs). Complexes of ion-exchange resin and dextromethorphan, a model drug, were prepared using different particle sizes of the resins. Aqueous colloidal dispersions of ethylcellulose (EC) and poly(vinyl acetate) (Kollicoat SR30D) were used for fluid-bed coating. Based on drug loading, release profiles, and scanning electron microscopy (SEM) images, the coated particles were granulated with suitable tablet excipients and then compressed into the tablets. Drug release profiles and SEM pictures were compared before and after the manufacturing processes. As the particle size of resins increased, the drug loading and release rate decreased due to the reduced effective diffusion coefficient and surface area. Higher coating level decreased the release rate further. In contrast to EC, Kollicoat SR30D coated particles could be compressed into tablets without any rupture or cracks on the coating since the mechanical properties of the polymer was more resistant to the manufacturing processes. This resulted in no significant changes in release rates. SEM showed the mechanical strength of the polymers affected the morphological change after compression. When the drug release profiles were applied into Boyd model and Higuchi equation, the linear relationship was observed, indicating that the diffusion within the resin matrix is the rate-controlling step.

  17. Ionic polymer metal composite actuators employing irradiation-crosslinked sulfonated poly(styrene-ran-ethylene) as ion-exchange membranes

    Science.gov (United States)

    Wang, Xuanlun; Cheng, Tai-Hong; Xu, Liang; Oh, Il-Kwon

    2009-07-01

    Ionic polymer metal composites (IPMC) are soft polymeric smart materials having large displacement at low voltage in moist environments or water. This type of actuators consists of an ionic membrane and noble metal electrodes plated on both surfaces. The ion-exchange membrane, Nafion, remains as the benchmark for a majority of research and development in IPMC technology. In this research, we employed sulfonated poly(styrene-ran-ethylene) (SPSE) that is crosslinked by UV irradiation as a novel ionic membrane. The crosslinking reaction between polymer matrix and crosslinking agent was proved by FTIR analysis. The sulfonic acid groups were stable during the UV irradiation crosslinking process. Water uptake, ion exchange capacity, and sulfonation degree are characterized for both pure SPSE and crosslinked SPSE membrane. The bending responses of SPSE actuators under both direct current (DC) and alternating current (AC) excitations were investigated. The voltage-current behaviors of the actuators under AC excitations are also measured. Results showed the crosslinked SPSE actuators have better electromechanical performance than that of pure SPSE actuator with regard to tip displacement.

  18. N- and O- ligand doped mesoporous silica-chitosan hybrid beads for the efficient, sustainable and selective recovery of rare earth elements (REE) from acid mine drainage (AMD): Understanding the significance of physical modification and conditioning of the polymer.

    Science.gov (United States)

    Ramasamy, Deepika Lakshmi; Puhakka, Ville; Iftekhar, Sidra; Wojtuś, Anna; Repo, Eveliina; Ben Hammouda, Samia; Iakovleva, Evgenia; Sillanpää, Mika

    2018-04-15

    Silica-chitosan hybrid beads were synthesized via three different methods to investigate the selective recovery of REE from AMD. The influence of amino/non-amino silanes, high molecular weight/high viscous chitosan and N-/O- based ligands were studied and their effects on REE removal efficiencies were analyzed. The adsorption efficiencies of three various groups of modified beads were inspected with respect to feed pH, in a single and a multi-component system, and their affinities towards the light and heavy rare earth elements (LREE/ HREEs) were interpreted to understand the intra-series REE separation behavior. The focus of the study was mainly directed towards utilizing these fabricated beads for the recovery of valuable REEs from the real AMD obtained at three different sampling depths which was found rich in iron, sulfur and aluminum. Moreover, the selectivity of the beads towards REEs improved with silanized and ligand immobilized gels and their impacts on REE recovery in the presence of competing ions were successfully presented in this paper. Also, the synthesized beads showed rapid REE adsorption and recovery within a process time of 5 min. Group II adsorbents, synthesized by forming silica-chitosan hybrid beads followed by PAN/acac modifications, showed superiority over the other groups of adsorbents. Copyright © 2018 Elsevier B.V. All rights reserved.

  19. Novel tentacle-type polymer stationary phase grafted with anion exchange polymer chains for open tubular CEC of nucleosides and proteins.

    Science.gov (United States)

    Aydoğan, Cemil; Çetin, Kemal; Denizli, Adil

    2014-08-07

    A novel and simple method for preparation of a tentacle-type polymer stationary phase grafted with polyethyleneimine (PEI) anion exchanger was developed for open tubular capillary electrochromatography (OT-CEC) of nucleosides and proteins. The polymeric stationary phase was prepared using 3-chloro-2-hydroxypropyl methacrylate (HPMA-Cl)-based reactive monomer. The preparation procedure included pretreatment of the capillary inner wall, silanization, in situ graft polymerization with HPMA-Cl and PEI modification. To compare with the tentacle-type capillary column with PEI functionalization, a monolayer capillary column without PEI functionalization was also prepared. The electrochromatographic characterization of the prepared open tubular column was performed using alkylbenzenes. The electroosmotic flow (EOF) with regard to PEI concentrations and the running buffer pH was investigated. The separation conditions of the nucleosides and the proteins were optimized. The modified tentacle-type column with high anion exchange capacity has proven to afford better retention and resolution for the separation of nucleosides and proteins. The PEI functionalization column can also provide long-term stable use for biomolecule separation using a single capillary with relative standard deviation values of retention times of less than 2%. The results indicate that the present method for open tubular capillary preparation with a HPMA-Cl-based reactive monomer is promising for OT-CEC biomolecule separation.

  20. Anion Effects on the Ion Exchange Process and the Deformation Property of Ionic Polymer Metal Composite Actuators

    Directory of Open Access Journals (Sweden)

    Wataru Aoyagi

    2016-06-01

    Full Text Available An ionic polymer-metal composite (IPMC actuator composed of a thin perfluorinated ionomer membrane with electrodes plated on both surfaces undergoes a large bending motion when a low electric field is applied across its thickness. Such actuators are soft, lightweight, and able to operate in solutions and thus show promise with regard to a wide range of applications, including MEMS sensors, artificial muscles, biomimetic systems, and medical devices. However, the variations induced by changing the type of anion on the device deformation properties are not well understood; therefore, the present study investigated the effects of different anions on the ion exchange process and the deformation behavior of IPMC actuators with palladium electrodes. Ion exchange was carried out in solutions incorporating various anions and the actuator tip displacement in deionized water was subsequently measured while applying a step voltage. In the step voltage response measurements, larger anions such as nitrate or sulfate led to a more pronounced tip displacement compared to that obtained with smaller anions such as hydroxide or chloride. In AC impedance measurements, larger anions generated greater ion conductivity and a larger double-layer capacitance at the cathode. Based on these mechanical and electrochemical measurements, it is concluded that the presence of larger anions in the ion exchange solution induces a greater degree of double-layer capacitance at the cathode and results in enhanced tip deformation of the IPMC actuators.

  1. The development of new transparent and ion-exchangeable polymer blends for chemical sensing

    Science.gov (United States)

    Gao, Letian

    A polymer blend formulation originally patented by NASA has been modified for use in spectroscopic sensing. The cured polymer blend is a mixture of poly(acrylic acid) (PAA) in glutaraldehyde cross-linked poly(vinyl alcohol) (PVA). With only the polymer blend directly applied as a fiber-optic cladding, aqueous Cu(II) ion can be detected as low as 10sp{-6} M by using a light-emitting diode at 810 nm as a light source. A blend-clad fiber-optic sensor can be regenerated at least 25x without significant deterioration. Subsequent to the first work, several new PVA-based polymer blends with polyelectrolytes such as Poly(diallydimethylammonium chloride) (PDMDAAC), Nafion, Poly(styrenesulfonic acid) (PSSA) and Poly(vinylbenzyltrimethylammonium chloride) (PVTAC) were developed. The blends have clear near-UV and visible spectral regions for direct spectroscopic sensing and they can readily concentrate cations and anions from aqueous solutions into a medium which has a suitable refractive index for an optical cladding on glass or silica surfaces. Three of the polymer blends, Nafion/PVA, PAA/PVA and PVTAC/PVA, were covalently coated onto planar glass and ITO-glass substrates using silane coupling reagents, i.e. 3-glycidoxypropyltrimethoxysilane (GPTS) or 3-aminopropyltriethoxysilane (APTS). Such covalently attached thin films remained well-adhered to oxide surfaces even in solutions of low pH. The potential use of these new materials for chemical sensing was also demonstrated by applying them to multiple internal reflection and hybrid spectroelectrochemical devices as thin films the prototype analytes as: Fe(CN)sb6sp{3-}, Ru(BiPy)sb3sp{2+} and Ru(CN)sb6sp{4-}. Well-defined and reversible cyclic voltammgrams were obtained, and satisfactory electrochemical modulation was achieved. The feasibility of improving sensor selectivity was explored with PVA-based polymer blend modified sensor that combines three modes of selectivity: charge-selective partitioning, electrolysis potential

  2. Hierarchically templated beads with tailored pore structure for phosphopeptide capture and phosphoproteomics

    DEFF Research Database (Denmark)

    Wierzbicka, Celina; Torsetnes, Silje B.; Jensen, Ole N.

    2017-01-01

    Two templating approaches to produce imprinted phosphotyrosine capture beads with a controllable pore structure are reported and compared with respect to their ability to enrich phosphopeptides from a tryptic peptide mixture. The beads were prepared by the polymerization of urea-based host monomers...... and crosslinkers inside the pores of macroporous silica beads with both free and immobilized template. In the final step the silica was removed by fluoride etching resulting in mesoporous polymer replicas with narrow pore size distributions, pore diameters ≈ 10 nm and surface area > 260 m2 g-1. The beads displayed...

  3. Towards high capacity latex-coated porous polymer monoliths as ion-exchange stationary phases.

    Science.gov (United States)

    Hutchinson, Joseph P; Hilder, Emily F; Shellie, Robert A; Smith, Jason A; Haddad, Paul R

    2006-02-01

    The preparation of high capacity agglomerated monolithic ion-exchangers for capillary ion chromatography is described. Post-modification of reactive monoliths was investigated as an alternative to co-polymerisation of a suitable functional monomer with an overarching goal of increasing ion-exchange capacity. Direct sulfonation of poly styrene-co-divinyl benzene monoliths using concentrated sulfuric acid or chlorosulfonic acid was unsuccessful even for monoliths containing as low as 8% crosslinker. In contrast, chemical transformation of reactive monoliths containing glycidyl methacrylate was used to increase the ion-exchange capacity by up to more than thirty-fold with ion exchange capacities of 14-29 microequiv g(-1) achieved. Three different reactions were considered, including reaction with 4-hydroxybenenesulfonic acid under basic conditions; reaction with thiobenzoic acid followed by transformation to a reactive thiol and the subsequent oxidation to the sulfonic acid; and direct sulfonation with sodium sulfite. Of these, the reaction with sodium sulfite resulted in the most significant increase in the capacity and the best separation performance. In the isocratic mode separation efficiencies of over 13,500 plates m(-1) were observed (for iodate). The separation of seven inorganic anions was also demonstrated using a hydroxide gradient.

  4. Hydrodynamic Torques and Rotations of Superparamagnetic Bead Dimers

    Science.gov (United States)

    Pease, Christopher; Etheridge, J.; Wijesinghe, H. S.; Pierce, C. J.; Prikockis, M. V.; Sooryakumar, R.

    Chains of micro-magnetic particles are often rotated with external magnetic fields for many lab-on-a-chip technologies such as transporting beads or mixing fluids. These applications benefit from faster responses of the actuated particles. In a rotating magnetic field, the magnetization of superparamagnetic beads, created from embedded magnetic nano-particles within a polymer matrix, is largely characterized by induced dipoles mip along the direction of the field. In addition there is often a weak dipole mop that orients out-of-phase with the external rotating field. On a two-bead dimer, the simplest chain of beads, mop contributes a torque Γm in addition to the torque from mip. For dimers with beads unbound to each other, mop rotates individual beads which generate an additional hydrodynamic torque on the dimer. Whereas, mop directly torques bound dimers. Our results show that Γm significantly alters the average frequency-dependent dimer rotation rate for both bound and unbound monomers and, when mop exceeds a critical value, increases the maximum dimer rotation frequency. Models that include magnetic and hydrodynamics torques provide good agreement with the experimental findings over a range of field frequencies.

  5. Scalable 3D bicontinuous fluid networks: polymer heat exchangers toward artificial organs.

    Science.gov (United States)

    Roper, Christopher S; Schubert, Randall C; Maloney, Kevin J; Page, David; Ro, Christopher J; Yang, Sophia S; Jacobsen, Alan J

    2015-04-17

    A scalable method for fabricating architected materials well-suited for heat and mass exchange is presented. These materials exhibit unprecedented combinations of small hydraulic diameters (13.0-0.09 mm) and large hydraulic-diameter-to-thickness ratios (5.0-30,100). This process expands the range of material architectures achievable starting from photopolymer waveguide lattices or additive manufacturing. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Behavior study of spend ion exchange resins immobilized in pyrolyzed polymer matrix

    International Nuclear Information System (INIS)

    Ramos, P.B; Fuentes, N.O; Luca, V.

    2012-01-01

    The pyrolysis of spent ion exchange resins contained in epoxy resins represents an attractive alternative to cementation as a confining method. In this sense, a significant reduction of volume can be achieved, as well as avoiding the dispersion of the exhausted ion exchange resin by the means of an epoxy resin used as a matrix, while potentially limiting the release of highly radioactive long life isotopes such us Cs-137, Sr-90 and Co-60 among others. Three types of monoliths were made: (i) epoxy resin, (ii) epoxy resin with carbon and (iii) a binder of epoxy resin and clay. In every case, the monolith contained the ion exchange resin. They were prepared by the mixing of resin pearl loaded with epoxy cations and a subsequent pyrolysis process with a temperature increase ratio of 2 o C /min reaching maximum values in the range between 200 o C - 800 o C, remaining in it for 1 hour. Monoliths obtained for each final temperature had been characterized to obtain data corresponding to the mass loss, volume reduction and lixiviation, as well as mechanical and microstructural properties (author)

  7. Reverse adhesion of a gecko-inspired synthetic adhesive switched by an ion-exchange polymer-metal composite actuator.

    Science.gov (United States)

    Guo, Dong-Jie; Liu, Rui; Cheng, Yu; Zhang, Hao; Zhou, Li-Ming; Fang, Shao-Ming; Elliott, Winston Howard; Tan, Wei

    2015-03-11

    Inspired by how geckos abduct, rotate, and adduct their setal foot toes to adhere to different surfaces, we have developed an artificial muscle material called ion-exchange polymer-metal composite (IPMC), which, as a synthetic adhesive, is capable of changing its adhesion properties. The synthetic adhesive was cast from a Si template through a sticky colloid precursor of poly(methylvinylsiloxane) (PMVS). The PMVS array of setal micropillars had a high density of pillars (3.8 × 10(3) pillars/mm(2)) with a mean diameter of 3 μm and a pore thickness of 10 μm. A graphene oxide monolayer containing Ag globular nanoparticles (GO/Ag NPs) with diameters of 5-30 nm was fabricated and doped in an ion-exchanging Nafion membrane to improve its carrier transfer, water-saving, and ion-exchange capabilities, which thus enhanced the electromechanical response of IPMC. After being attached to PMVS micropillars, IPMC was actuated by square wave inputs at 1.0, 1.5, or 2.0 V to bend back and forth, driving the micropillars to actively grip or release the surface. To determine the adhesion of the micropillars, the normal adsorption and desorption forces were measured as the IPMC drives the setal micropillars to grip and release, respectively. Adhesion results demonstrated that the normal adsorption forces were 5.54-, 14.20-, and 23.13-fold higher than the normal desorption forces under 1.0, 1.5, or 2.0 V, respectively. In addition, shear adhesion or friction increased by 98, 219, and 245%, respectively. Our new technique provides advanced design strategies for reversible gecko-inspired synthetic adhesives, which might be used for spiderman-like wall-climbing devices with unprecedented performance.

  8. On-chip signal amplification of magnetic bead-based immunoassay by aviating magnetic bead chains.

    Science.gov (United States)

    Jalal, Uddin M; Jin, Gyeong Jun; Eom, Kyu Shik; Kim, Min Ho; Shim, Joon S

    2017-11-06

    In this work, a Lab-on-a-Chip (LOC) platform is used to electromagnetically actuate magnetic bead chains for an enhanced immunoassay. Custom-made electromagnets generate a magnetic field to form, rotate, lift and lower the magnetic bead chains (MBCs). The cost-effective, disposable LOC platform was made with a polymer substrate and an on-chip electrochemical sensor patterned via the screen-printing process. The movement of the MBCs is controlled to improve the electrochemical signal up to 230% when detecting beta-type human chorionic gonadotropin (β-hCG). Thus, the proposed on-chip MBC-based immunoassay is applicable for rapid, qualitative electrochemical point-of-care (POC) analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Feasibility of Marine Microalgae Immobilization in Alginate Bead for Marine Water Treatment: Bead Stability, Cell Growth, and Ammonia Removal

    Directory of Open Access Journals (Sweden)

    Chen-Lin Soo

    2017-01-01

    Full Text Available Sodium alginate is the most commonly used polymer matrix in microalgae immobilization for water treatment. However, the susceptibility of alginate matrixes to cation chelating agents and antigelling cation limits the use of alginates in estuarine and marine systems. Hence, the present study aims to investigate the stability of alginate bead in marine water and the feasibility of microalgae to grow when immobilized in alginate bead for marine water treatment. Different concentrations of alginate and hardening cation calcium were used to formulate beads. The beads were incubated in Guillard’s f/2 medium and shaken vigorously by using orbital shaker for 15 days. The results indicated that bead stability was enhanced by increasing alginate and CaCl2 concentrations. Subsequently, the marine microalga, Nannochloropsis sp., was immobilized in calcium alginate bead. The growth and ammoniacal-nitrogen (NH4+-N uptake by immobilized cell were compared with free cell culture in f/2 medium. Specific growth rate of immobilized cell (0.063 hr−1 was significantly higher than free cell (0.027 hr−1. There was no significant difference on specific uptake rate of free cell and immobilized cell; but immobilized cell removed significantly more NH4+-N (82.2% than free cell (47.3% culture at the end of the experiment. The present study demonstrated the potential use of alginate immobilization technique in marine microalgae culture and water treatment simultaneously.

  10. bEADS

    DEFF Research Database (Denmark)

    Williams, Peter Leslie; Overholt, Daniel

    2017-01-01

    While there are a great variety of digital musical interfaces available to the working musician, few offer the level of immediate, nuanced and instinctive interaction that one finds in an acoustic shaker. bEADS is a prototype of a digital musical instrument that utilises the gestural vocabulary...... associated with shaken idiophones and expands on the techniques and sonic possibilities associated with them. By using a bespoke physically informed synthesis engine, in conjunction with accelerometer and pressure sensor data, an actuated handheld instrument has been built that allows for quickly switching...... between widely differing percussive sound textures. The prototype has been evaluated by three experts with different levels of involvement in professional music making....

  11. High-productivity membrane adsorbers: Polymer surface-modification studies for ion-exchange and affinity bioseparations

    Science.gov (United States)

    Chenette, Heather C. S.

    This dissertation centers on the surface-modification of macroporous membranes to make them selective adsorbers for different proteins, and the analysis of the performance of these membranes relative to existing technology. The common approach used in these studies, which is using membrane technology for chromatographic applications and using atom transfer radical polymerization (ATRP) as a surface modification technique, will be introduced and supported by a brief review in Chapter 1. The specific approaches to address the unique challenges and motivations of each study system are given in the introduction sections of the respective dissertation chapters. Chapter 2 describes my work to develop cation-exchange membranes. I discuss the polymer growth kinetics and characterization of the membrane surface. I also present an analysis of productivity, which measures the mass of protein that can bind to the stationary phase per volume of stationary phase adsorbing material per time. Surprisingly and despite its importance, this performance measure was not described in previous literature. Because of the significantly shorter residence time necessary for binding to occur, the productivity of these cation-exchange membrane adsorbers (300 mg/mL/min) is nearly two orders of magnitude higher than the productivity of a commercial resin product (4 mg/mL/min). My work studying membrane adsorbers for affinity separations was built on the productivity potential of this approach, as articulated in the conclusion of Chapter 2. Chapter 3 focuses on the chemical formulation work to incorporate glycoligands into the backbone of polymer tentacles grown from the surface of the same membrane stationary phase. Emphasis is given to characterizing and testing the working formulation for ligand incorporation, and details about how I arrived at this formulation are given in Appendix B. The plant protein, or lectin, Concanavalin A (conA) was used as the target protein. The carbohydrate affinity

  12. Coordination Chemistry inside Polymeric Nanoreactors: Metal Migration and Cross-Exchange in Amphiphilic Core-Shell Polymer Latexes

    Directory of Open Access Journals (Sweden)

    Si Chen

    2016-01-01

    Full Text Available A well-defined amphiphilic core-shell polymer functionalized with bis(p-methoxy-phenylphosphinophenylphosphine (BMOPPP in the nanogel (NG core has been obtained by a convergent RAFT polymerization in emulsion. This BMOPPP@NG and the previously-reported TPP@NG (TPP = triphenylphosphine and core cross-linked micelles (L@CCM; L = TPP, BMOPPP having a slightly different architecture were loaded with [Rh(acac(CO2] or [RhCl(COD]2 to yield [Rh(acac(CO(L@Pol] or [RhCl(COD(L@Pol] (Pol = CCM, NG. The interparticle metal migration from [Rh(acac(CO(TPP@NG] to TPP@NG is fast at natural pH and much slower at high pH, the rate not depending significantly on the polymer architecture (CCM vs. NG. The cross-exchange using [Rh(acac(CO(BMOPPP@Pol] and [RhCl(COD(TPP@Pol] (Pol = CCM or NG as reagents at natural pH is also rapid (ca. 1 h, although slower than the equivalent homogeneous reaction on the molecular species (<5 min. On the other hand, the subsequent rearrangement of [Rh(acac(CO(TPP@Pol] and [RhCl(COD(TPP@Pol] within the TPP@Pol core and of [Rh(acac(CO(BMOPPP@Pol] and [RhCl(COD(BMOPPP@Pol] within the BMOPPP@Pol core, leading respectively to [RhCl(CO(TPP@Pol2] and [RhCl(CO(BMOPPP@Pol2], is much more rapid (<30 min than on the corresponding homogeneous process with the molecular species (>24 h.

  13. Characterization of anion exchange ionomers in hybrid polymer electrolyte fuel cells.

    Science.gov (United States)

    Unlü, Murat; Zhou, Junfeng; Anestis-Richard, Irene; Kohl, Paul A

    2010-12-17

    Anion exchange ionomers (AEI) synthesized here were characterized by use of a novel fuel cell configuration. The new analysis method involves assembling the AEI electrode of interest as the cathode in a hybrid, acid/alkaline, fuel cell configuration. The hybrid cell includes a conventional proton conducting anode/membrane half-cell along with the anionic conductor of interest at the cathode. Electrochemical impedance spectroscopy and voltammetry were used to evaluate the performance of the hybrid AEI-containing fuel cell with H₂ and O₂. In particular, the AEI electrode response in impedance spectroscopy was easily identified because the contributions from other components are largely minimized in the presented hybrid cell configuration. The properties of ionomers used in the AEI electrode were shown to have a substantial effect on the electrode performance. Low catalyst utilization, due to high water uptake and low conductivity, was identified as the major causes of poor performance in AEI electrodes.

  14. Liquid anion exchangers (LAE) as novel receptors for plutonium pertraction across polymer immobilized liquid membranes

    International Nuclear Information System (INIS)

    Sonawane, J.V.; Anil Kumar; Sawant, S.R.; Singh, R.K.; Bajpai, D.D.; Shukla, J.P.

    1999-03-01

    The diffusion-limited and amine-facilitated Pu 4+ cation permeation in nitric acid media across a polymer immobilized liquid membrane (PILM) has been investigated to quantify the membrane carrier type effects on its transport. Primene JM-T (JMT) as primary, Amberlite LA-2 (Amb LA-2) as secondary, trilaurylamine (TLA] and triiso-octyl amine (TIOA) as tertiary and Adogen-464 (Ado-464) and Aliquat-336 (Ali-336) as quaternary amines as typical examples of nitrogen containing basic extractants are tested as the carriers. After suitable dilutions, the receptors are immobilized on a microporous polymeric support which are held within the pores by capillary forces. Both the composition of the organic membrane solvents and type of amine carriers exert a marked effect on plutonium permeation. Recovery of Pu steadily increases from primary to quaternary amines; its permeability across PILM roughly follows the order quaternary > tertiary > secondary > primary, similar to that generally observed in liquid-liquid distribution experiments. More than 95% pertraction of Pu(IV) is easily accomplished using tertiary or quaternary amine as ionophores across PILM in single run employing a feed solution containing about 5 mg dm -3 Pu in 4 M nitric acid solution while the receiving phase is 0.1M NH 2 OH.HCl prepared in 0.3M HNO 3 . On the other hand, plutonium permeation at 4M HNO 3 under similar experimental conditions using other types of amines as carriers namely primary amine, Pri JM-T afforded only 19% and 49% by Amb LA-2 in 6-7h runs. Results of the detailed study to evaluate the effect of other contaminants on Pu transport are also discussed. (author)

  15. Wood Xylowall: New process to reduce water exchange by an intra-graft of polymer

    Science.gov (United States)

    Uyttenhove, Anne; Tilquin, Bernard

    2005-07-01

    Our research shows that poplar treated with selected monomer mixture and then irradiated at 50 kGy reduces the water exchange without adversely altering the desirable qualities of wood. Moreover, the environment is not polluted. To retard changes in moisture content and dimensions, different commercial Radcures (UCB) were tested. A comparative study on the water retention showed significant reduction between non-treated and Xylowall wood for the species: poplar. The physical and mechanical measurements (density, volumetric shrinkage, elasticity, rupture, impact bending, hardness, compression strength) on poplar and pine show that the properties of the wood are not affected negatively by Xylowall treatment with irradiation. Moreover, the process does not discharge any toxic volatile residues into the atmosphere as proven by GC-MS trace analysis of heated wood samples. The stereomicroscope by imagery reveals an impregnation of 0.5 mm on cross-section of darker-stained areas, and sometimes more due to the texture (the relative size and arrangement of the wood cells) of the wood.

  16. Immobilization of inorganic ion-exchanger into bio-polymer foams - Application to cesium sorption

    International Nuclear Information System (INIS)

    Vincent, Chloe; Hertz, Audrey; Barre, Yves; Vincent, Thierry; Guibal, Eric

    2014-01-01

    Nickel-potassium ferrocyanide (along with other ferrocyanide sub-products, as shown by mineralization, SEM-EDX and XRD analyses) has been immobilized in highly porous discs of chitin for the sorption of Cs(I) from near neutral solutions. The immobilization process allows synthesizing stable materials that can bind up to 80 mg Cs g -1 (i.e., 240 mg Cs g -1 ion-exchanger). Cesium sorption is hardly affected by the pH between pH 2 and 8. The sorbent is selective to Cs(I) even in the presence of high concentrations of Na(I), K(I), Rb(I) or NH 4+ . The pseudo-second order rate equation fits well kinetic profiles: the rate coefficient increases with the flow rate of recirculation (to force the access to potentially non-interconnected pores), as an evidence of the control of uptake kinetics by diffusion properties. In fixed-bed columns, the breakthrough curve is accurately described by the Clark model and the sorption capacity (at sorbent saturation) is consistent with the values obtained in sorption isotherms. Preliminary tests performed on 137 Cs spiked solutions confirm the efficiency of the material for the treatment of effluents bearing radionuclides. (authors)

  17. Wood Xylowall: New process to reduce water exchange by an intra-graft of polymer

    International Nuclear Information System (INIS)

    Uyttenhove, Anne; Tilquin, Bernard

    2005-01-01

    Our research shows that poplar treated with selected monomer mixture and then irradiated at 50 kGy reduces the water exchange without adversely altering the desirable qualities of wood. Moreover, the environment is not polluted. To retard changes in moisture content and dimensions, different commercial Radcures (UCB) were tested. A comparative study on the water retention showed significant reduction between non-treated and Xylowall wood for the species: poplar. The physical and mechanical measurements (density, volumetric shrinkage, elasticity, rupture, impact bending, hardness, compression strength) on poplar and pine show that the properties of the wood are not affected negatively by Xylowall treatment with irradiation. Moreover, the process does not discharge any toxic volatile residues into the atmosphere as proven by GC-MS trace analysis of heated wood samples. The stereomicroscope by imagery reveals an impregnation of 0.5 mm on cross-section of darker-stained areas, and sometimes more due to the texture (the relative size and arrangement of the wood cells) of the wood

  18. Heat and fuel coupled operation of a high temperature polymer electrolyte fuel cell with a heat exchanger methanol steam reformer

    Science.gov (United States)

    Schuller, G.; Vázquez, F. Vidal; Waiblinger, W.; Auvinen, S.; Ribeirinha, P.

    2017-04-01

    In this work a methanol steam reforming (MSR) reactor has been operated thermally coupled to a high temperature polymer electrolyte fuel cell stack (HT-PEMFC) utilizing its waste heat. The operating temperature of the coupled system was 180 °C which is significantly lower than the conventional operating temperature of the MSR process which is around 250 °C. A newly designed heat exchanger reformer has been developed by VTT (Technical Research Center of Finland LTD) and was equipped with commercially available CuO/ZnO/Al2O3 (BASF RP-60) catalyst. The liquid cooled, 165 cm2, 12-cell stack used for the measurements was supplied by Serenergy A/S. The off-heat from the electrochemical fuel cell reaction was transferred to the reforming reactor using triethylene glycol (TEG) as heat transfer fluid. The system was operated up to 0.4 A cm-2 generating an electrical power output of 427 Wel. A total stack waste heat utilization of 86.4% was achieved. It has been shown that it is possible to transfer sufficient heat from the fuel cell stack to the liquid circuit in order to provide the needed amount for vaporizing and reforming of the methanol-water-mixture. Furthermore a set of recommendations is given for future system design considerations.

  19. Simultaneously Tailoring Surface Energies and Thermal Stabilities of Cellulose Nanocrystals Using Ion Exchange: Effects on Polymer Composite Properties for Transportation, Infrastructure, and Renewable Energy Applications.

    Science.gov (United States)

    Fox, Douglas M; Rodriguez, Rebeca S; Devilbiss, Mackenzie N; Woodcock, Jeremiah; Davis, Chelsea S; Sinko, Robert; Keten, Sinan; Gilman, Jeffrey W

    2016-10-12

    Cellulose nanocrystals (CNCs) have great potential as sustainable reinforcing materials for polymers, but there are a number of obstacles to commercialization that must first be overcome. High levels of water absorption, low thermal stabilities, poor miscibility with nonpolar polymers, and irreversible aggregation of the dried CNCs are among the greatest challenges to producing cellulose nanocrystal-polymer nanocomposites. A simple, scalable technique to modify sulfated cellulose nanocrystals (Na-CNCs) has been developed to address all of these issues. By using an ion exchange process to replace Na + with imidazolium or phosphonium cations, the surface energy is altered, the thermal stability is increased, and the miscibility of dried CNCs with a nonpolar polymer (epoxy and polystyrene) is enhanced. Characterization of the resulting ion exchanged CNCs (IE-CNCs) using potentiometry, inverse gas chromatography, dynamic vapor sorption, and laser scanning confocal microscopy reveals that the IE-CNCs have lower surface energies, adsorb less water, and have thermal stabilities of up to 100 °C higher than those of prepared protonated cellulose nanocrystals (H-CNCs) and 40 °C higher than that of neutralized Na-CNC. Methyl(triphenyl)phosphonium exchanged cellulose nanocrystals (MePh 3 P-CNC) adsorbed 30% less water than Na-CNC, retained less water during desorption, and were used to prepare well-dispersed epoxy composites without the aid of a solvent and well-dispersed polystyrene nanocomposites using a melt blending technique at 195 °C. Predictions of dispersion quality and glass transition temperatures from molecular modeling experiments match experimental observations. These fiber-reinforced polymers can be used as lightweight composites in transportation, infrastructure, and renewable energy applications.

  20. Microfabricated Passive Magnetic Bead separators

    DEFF Research Database (Denmark)

    Hansen, Mikkel Fougt; Lund-Olesen, Torsten; Smistrup, Kristian

    2006-01-01

    The use and manipulation of functionalized magnetic beads for bioanalysis in lab-on-a-chip systems is receiving growing interest. We have developed microfluidic systems with integrated magnetic structures for the capture and release of magnetic beads. The systems are fabricated in silicon by deep...... reactive ion etching combined with a number of metal deposition and etching steps followed by anodic bonding of a pyrex lid....

  1. Formulation of Synthesized Zinc Oxide Nanopowder into Hybrid Beads for Dye Separation

    Directory of Open Access Journals (Sweden)

    H. Shokry Hassan

    2014-01-01

    Full Text Available The sol-gel prepared zinc oxide nanopowder was immobilized onto alginate-polyvinyl alcohol polymer blend to fabricate novel biocomposite beads. Various physicochemical characterization techniques have been utilized to identify the crystalline, morphological, and chemical structures of both the fabricated zinc oxide hybrid beads and their corresponding zinc oxide nanopowder. The thermal stability investigations demonstrate that ZnO nanopowder stability dramatically decreased with its immobilization into the polymeric alginate and PVA matrix. The formulated beads had very strong mechanical strength and they are difficult to be broken up to 1500 rpm. Moreover, these hybrid beads are chemically stable at the acidic media (pH < 7 especially within the pH range of 2–7. Finally, the applicability of the formulated ZnO hybrid beads for C.I. basic blue 41 (BB41 decolorization from aqueous solution was examined.

  2. Interpenetrating network hydrogel beads of carboxymethylcellulose and egg albumin for controlled release of lipid lowering drug.

    Science.gov (United States)

    Boppana, Rashmi; Kulkarni, Raghavendra V; Mutalik, Srinivas S; Setty, C Mallikarjun; Sa, Biswanath

    2010-01-01

    Novel interpenetrating network hydrogel beads of sodium carboxymethylcellulose and egg albumin loaded with a lipid lowering drug, simvastatin, were prepared by ionotropic gelation and covalent cross-linking method. The IPN beads were characterized by differential scanning colorimetric analysis, X-ray diffractometry to understand the crystalline nature of the drug after entrapment into IPN matrix. Fourier transform infrared spectroscopy was used to find the chemical stability of drug in the polymer matrix and scanning electron microscopy was performed to study the surface morphology. The ionically cross-linked beads were capable of releasing drug up to 7 h, whereas the drug release was extended up to 12 h in case of dual cross-linked beads. The beads which were prepared with higher concentration of glutaraldehyde released the drug more slowly. The release data were fitted to an empirical equation to determine the transport mechanism, which indicated the non-Fickian trend for drug transport.

  3. Cross-linked poly (vinyl alcohol)/sulfosuccinic acid polymer as an electrolyte/electrode material for H2-O2 proton exchange membrane fuel cells

    Science.gov (United States)

    Ebenezer, D.; Deshpande, Abhijit P.; Haridoss, Prathap

    2016-02-01

    Proton exchange membrane fuel cell (PEMFC) performance with a cross-linked poly (vinyl alcohol)/sulfosuccinic acid (PVA/SSA) polymer is compared with Nafion® N-115 polymer. In this study, PVA/SSA (≈5 wt. % SSA) polymer membranes are synthesized by a solution casting technique. These cross-linked PVA/SSA polymers and Nafion are used as electrolytes and ionomers in catalyst layers, to fabricate different membrane electrode assemblies (MEAs) for PEMFCs. Properties of each MEA are evaluated using scanning electron microscopy, contact angle measurements, impedance spectroscopy and hydrogen pumping technique. I-V characteristics of each cell are evaluated in a H2-O2 fuel cell testing fixture under different operating conditions. PVA/SSA ionomer causes only an additional ≈4% loss in the anode performance compared to Nafion ionomer. The maximum power density obtained from PVA/SSA based cells range from 99 to 117.4 mW cm-2 with current density range of 247 to 293.4 mA cm-2. Ionic conductivity of PVA/SSA based cells is more sensitive to state of hydration of MEA, while maximum power density obtained is less sensitive to state of hydration of MEA. Maximum power density of cross-linked PVA/SSA membrane based cell is about 35% that of Nafion® N-115 based cell. From these results, cross-linked PVA/SSA polymer is identified as potential candidate for PEMFCs.

  4. Microfluidic magnetic bead conveyor belt.

    Science.gov (United States)

    van Pelt, Stijn; Frijns, Arjan; den Toonder, Jaap

    2017-11-07

    Magnetic beads play an important role in the miniaturization of clinical diagnostics systems. In lab-on-chip platforms, beads can be made to link to a target species and can then be used for the manipulation and detection of this species. Current bead actuation systems utilize complex on-chip coil systems that offer low field strengths and little versatility. We demonstrate a novel system based on an external rotating magnetic field and on-chip soft-magnetic structures to focus the field locally. These structures were designed and optimized using finite element simulations in order to create a number of local flux density maxima. These maxima, to which the magnetic beads are attracted, move over the chip surface in a continuous way together with the rotation of the external field, resulting in a mechanism similar to that of a conveyor belt. A prototype was fabricated using PDMS molding techniques mixed with iron powder for the magnetic structures. In the subsequent experiments, a quadrupole electromagnet was used to create the rotating external field. We observed that beads formed agglomerates that rolled over the chip surface, just above the magnetic structures. Field rotation frequencies between 0.1-50 Hz were tested resulting in magnetic bead speeds of over 1 mm s -1 for the highest frequency. With this, we have shown that our novel concept works, combining a simple design and simple operation with a powerful and versatile method for bead actuation. This makes it a promising method for further research and utilization in lab-on-chip systems.

  5. Polymer and bitumen modified OPC for the immobilisation of ILW

    International Nuclear Information System (INIS)

    Johnson, D.I.; Worrall, G.; Phillips, D.C.

    1986-05-01

    A detailed study has been made of the modification of ordinary Portland cement with polymeric additives, and of the properties of waste forms based on these matrix materials. The additives were styrene butadiene and bitumen emulsions, and epoxide and polyurethane resins: the simulated wastes were organic ion exchanger beads, PWR evaporator concentrate, reprocessing concentrate and Magnox metal. The effect of polymer:cement (p:c) and water:cement ratios on the properties of the hardened cement paste has been comprehensively investigated. Substantial increases in strain to failure, and modest reductions in permeability to water and leach rates for 137 Cs, are obtained at p:c >= 0.2. Much larger volume fractions of organic ion exchange beads can be encapsulated in polymer modified OPC than in unmodified OPC, perhaps because of their better strain capability. The radiation stability of cemented PWR evaporator concentrate is better for a polymer modified matrix than an unmodified OPC matrix. Two hundred litre trials have been successfully demonstrated. (author)

  6. Polyethylenimine modified poly(ethylene terephthalate) capillary channeled-polymer fibers for anion exchange chromatography of proteins.

    Science.gov (United States)

    Jiang, Liuwei; Jin, Yi; Marcus, R Kenneth

    2015-09-04

    Native poly(ethylene terephthalate) (PET) capillary-channeled polymer (C-CP) fibers have been previously studied as stationary phases for reversed phase and affinity protein separations. In this study, surface modified PET C-CP fibers were evaluated for the anion exchange separation of proteins. The native PET C-CP fibers were aminated using polyethylenimine (PEI) followed by a 1,4-butanediol diglycidyl ether (BUDGE) cross-linking step. Subsequent PEI/BUDGE treatments can be employed to further develop the polyamine layer on the fiber surfaces. The PEI densities of the modified fibers were quantified through the ninhydrin reaction, yielding values of 0.43-0.89μmolg(-1). The surface modification impact on column permeability was found to be 0.66×10(-11) to 1.33×10(-11)m(2), depending on the modification time and conditions. The dynamic binding capacities of the modified fiber media were determined to be 1.99-8.54mgmL(-1) bed volume, at linear velocities of 88-438cmmin(-1) using bovine serum albumin as the model protein. It was found that increasing the mobile phase linear velocity (up to 438cmmin(-1)) had no effect on the separation quality for a synthetic protein mixture, reflecting the lack of van Deemter C-term effects for the C-CP fiber phase. The low-cost, easy modification method and the capability of fast protein separation illustrate great potential in the use of PEI/BUDGE-modified PET C-CP fibers for high-throughput protein separation and downstream processing. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Numerical simulation of drag-reducing channel flow by using bead-spring chain model

    International Nuclear Information System (INIS)

    Fujimura, M.; Atsumi, T.; Mamori, H.; Iwamoto, K.; Murata, A.; Masuda, M.; Ando, H.

    2017-01-01

    Highlights: • Numerical simulations of drag-reduced turbulent flow by polymer additives were performed by using a discrete element model. • A decreasing pressure-strain correlation mainly contributes to drag reduction by polymer addition. • Energy transport by the polymer attenuates the turbulence. • The viscoelastic effects on the drag-reducing flow are intensified with increasing relaxation time of polymer. • The polymer energy transport is related to the orientation of the polymer. - Abstract: Numerical simulations of the drag-reducing turbulent channel flow caused by polymer addition are performed. A bead-spring chain model is employed as a model of polymer aggregation. The model consists of beads and springs to represent the polymer dynamics. Three drag-reduction cases are studied with different spring constants that correspond to the relaxation time of the polymer. The energy budget is mainly focused upon to discuss the drag-reduction mechanism. Our results show that a decreasing pressure-strain correlation mainly contributes to strengthening the anisotropy of the turbulence. Furthermore, energy transport by the polymer models attenuates the turbulence. These viscoelastic effects on the drag-reducing flow are intensified with decreasing spring constant. By visualizing the flow field, it is found that this polymer energy transport is related to the orientation of the polymer.

  8. Gellan Gum/Pectin Beads Are Safe and Efficient for the Targeted Colonic Delivery of Resveratrol

    Directory of Open Access Journals (Sweden)

    Fabíola Garavello Prezotti

    2018-01-01

    Full Text Available This work addresses the establishment and characterization of gellan gum:pectin (GG:P biodegradable mucoadhesive beads intended for the colon-targeted delivery of resveratrol (RES. The impact of the polymer carrier system on the cytotoxicity and permeability of RES was evaluated. Beads of circular shape (circularity index of 0.81 with an average diameter of 914 μm, Span index of 0.29, and RES entrapment efficiency of 76% were developed. In vitro drug release demonstrated that beads were able to reduce release rates in gastric media and control release for up to 48 h at an intestinal pH of 6.8. Weibull’s model correlated better with release data and b parameter (0.79 indicated that the release process was driven by a combination of Fickian diffusion and Case II transport, indicating that both diffusion and swelling/polymer chains relaxation are processes that contribute equally to control drug release rates. Beads and isolated polymers were observed to be safe for Caco-2 and HT29-MTX intestinal cell lines. RES encapsulation into the beads allowed for an expressive reduction of drug permeation in an in vitro triple intestinal model. This feature, associated with low RES release rates in acidic media, can favor targeted drug delivery from the beads in the colon, a promising behavior to improve the local activity of RES.

  9. Two kinds of ketoprofen enteric gel beads (CA and CS-SA using biopolymer alginate

    Directory of Open Access Journals (Sweden)

    Bingchao Cheng

    2018-03-01

    Full Text Available To obtain expected rapid-release and sustained-release of ketoprofen gel beads, this paper adopted biopolymer alginate to prepare alginate beads and chitosan-alginate gel beads. Formulation factors were investigated and optimized by the single factor test. The release of ketoprofen from calcium alginate gel beads in pH 1.0 hydrochloric acid solution was less than 10% during 2 h, then in pH6.8 was about 95% during 45 min, which met the requirements of rapid-release preparations. However, the drug release of chitosan-alginate gel beads in pH1.0 was less than 5% during 2 h, then in pH6.8 was about 50% during 6 h and reached more than 95% during 12 h, which had a good sustained-release behavior. In addition, the release kinetics of keteprofen from the calcium alginate gel beads fitted well with the Korsmeyer–Peppas model and followed a case-II transport mechanism. However, the release of keteprofen from the chitosan-alginate gel beads exhibited a non-Fickian mechanism and based on the mixed mechanisms of diffusion and polymer relaxation from chitosan-alginate beads. In a word, alginate gel beads of ketoprofen were instant analgesic, while chitosan-alginate gel beads could control the release of ketoprofen during gastro-intestinal tract and prolong the drug's action time. Keywords: Gel beads, Enteric rapid-release, Enteric sustained-release, Ketoprofen

  10. Reversible immobilization of laccase to poly(4-vinylpyridine) grafted and Cu(II) chelated magnetic beads: biodegradation of reactive dyes.

    Science.gov (United States)

    Bayramoğlu, Gülay; Yilmaz, Meltem; Arica, M Yakup

    2010-09-01

    Poly(4-vinyl pyridine), poly(VP), as a novel metal-chelating fibrous polymer was grafted on the magnetic beads. Poly(4-VP) grafted and/or Cu(II) ions chelated magnetic beads were used for reversible immobilization of Trametes versicolor laccase, and the amounts of immobilized laccase on the beads were determined as 36.8 and 56.4 mg/g beads, respectively. The adsorption of laccase on both modified magnetic beads appeared to follow the Langmuir isotherm model. The degradation of textile dyes with immobilized laccase on the metal chelated magnetic beads was evaluated in a batch system. Three different reactive textile dyes (i.e., Reactive Green 19, Reactive Red 2 and Reactive Brown 10) were successfully degraded in the enzyme reactor. It was observed that the decolorization rate varied widely with chemical structure and types of the substitute group of the reactive dye molecules. (c) 2010 Elsevier Ltd. All rights reserved.

  11. Preparation and thermal properties of chitosan/bentonite composite beads

    Directory of Open Access Journals (Sweden)

    Teofilović Vesna

    2014-01-01

    Full Text Available Due to their biodegradable and nontoxic nature, biopolymer composites are often used as remarkable adsorbents in treatment of wastewater. In this study chitosan/bentonite composite beads were obtained by addition of clay into the polymer using solution process. Before the composite preparation, bentonite was modified with surfactant cetyltrimethyl ammonium bromide (CTAB. The morphology of beads was examined by scanning electron microscopy (SEM. Thermal properties of the composite beads were studied by simultaneous thermogravimetry coupled with differential scanning calorimetry (SDT and differential scanning calorimetry (DSC. TG results showed that the complex decomposition mechanism of the composites depends on the preparation procedure. It was observed that the concentration of NaOH used for composites precipitation affects the final structure of beads. The influence of preparation procedure on the glass transition temperature Tg of chitosan/bentonite samples was not found (Tg values for all samples were about 144 °C. [Projekat Ministarstva nauke Republike Srbije, br. III45022 and ON172014 and Provincial Secretariat of Vojvodina for Science and Technological Development 114-451-2396/2011-01.

  12. Monosize magnetic hydrophobic beads for lysozyme purification under magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Altintas, Evrim Banu [Department of Chemistry, Hacettepe University, Beytepe, Ankara (Turkey); Denizli, Adil, E-mail: denizli@hacettepe.edu.tr [Department of Chemistry, Hacettepe University, Beytepe, Ankara (Turkey)

    2009-06-01

    Monosize and magnetic poly(glycidyl methacrylate-N-methacryloyl-(L)-tryptophan) [mPGMATrp] beads (1.6 {mu}m in diameter) were used for hydrophobic affinity capture of lysozyme from chicken egg-white. N-methacryloyl-(L)-tryptophan (MATrp), which gives hydrophobicity to the resulting polymer, was synthesized by reacting methacryloyl chloride and L-tryptophan methyl ester then characterized by Nuclear Magnetic Resonance (NMR). mPGMATrp beads were produced by dispersion polymerization in the presence of magnetite nano-powder. mPGMATrp beads were characterized by means of swelling studies, elemental analysis, Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM). Lysozyme adsorption experiments were performed under different experimental conditions (i.e., lysozyme concentration, temperature, and ionic strength) in magnetically stabilized fluidized bed system, (MSFB). Maximum adsorption capacity was 263.9 mg/g. It was observed that mPGMATrp beads can be used without significant loss in lysozyme adsorption capacity after 25 adsorption-elution cycle.

  13. Monosize magnetic hydrophobic beads for lysozyme purification under magnetic field

    International Nuclear Information System (INIS)

    Altintas, Evrim Banu; Denizli, Adil

    2009-01-01

    Monosize and magnetic poly(glycidyl methacrylate-N-methacryloyl-(L)-tryptophan) [mPGMATrp] beads (1.6 μm in diameter) were used for hydrophobic affinity capture of lysozyme from chicken egg-white. N-methacryloyl-(L)-tryptophan (MATrp), which gives hydrophobicity to the resulting polymer, was synthesized by reacting methacryloyl chloride and L-tryptophan methyl ester then characterized by Nuclear Magnetic Resonance (NMR). mPGMATrp beads were produced by dispersion polymerization in the presence of magnetite nano-powder. mPGMATrp beads were characterized by means of swelling studies, elemental analysis, Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM). Lysozyme adsorption experiments were performed under different experimental conditions (i.e., lysozyme concentration, temperature, and ionic strength) in magnetically stabilized fluidized bed system, (MSFB). Maximum adsorption capacity was 263.9 mg/g. It was observed that mPGMATrp beads can be used without significant loss in lysozyme adsorption capacity after 25 adsorption-elution cycle.

  14. Deterministic bead-in-droplet ejection utilizing an integrated plug-in bead dispenser for single bead-based applications

    Science.gov (United States)

    Kim, Hojin; Choi, In Ho; Lee, Sanghyun; Won, Dong-Joon; Oh, Yong Suk; Kwon, Donghoon; Sung, Hyung Jin; Jeon, Sangmin; Kim, Joonwon

    2017-04-01

    This paper presents a deterministic bead-in-droplet ejection (BIDE) technique that regulates the precise distribution of microbeads in an ejected droplet. The deterministic BIDE was realized through the effective integration of a microfluidic single-particle handling technique with a liquid dispensing system. The integrated bead dispenser facilitates the transfer of the desired number of beads into a dispensing volume and the on-demand ejection of bead-encapsulated droplets. Single bead-encapsulated droplets were ejected every 3 s without any failure. Multiple-bead dispensing with deterministic control of the number of beads was demonstrated to emphasize the originality and quality of the proposed dispensing technique. The dispenser was mounted using a plug-socket type connection, and the dispensing process was completely automated using a programmed sequence without any microscopic observation. To demonstrate a potential application of the technique, bead-based streptavidin-biotin binding assay in an evaporating droplet was conducted using ultralow numbers of beads. The results evidenced the number of beads in the droplet crucially influences the reliability of the assay. Therefore, the proposed deterministic bead-in-droplet technology can be utilized to deliver desired beads onto a reaction site, particularly to reliably and efficiently enrich and detect target biomolecules.

  15. Three-bead steering microswimmers

    Science.gov (United States)

    Rizvi, Mohd Suhail; Farutin, Alexander; Misbah, Chaouqi

    2018-02-01

    The self-propelled microswimmers have recently attracted considerable attention as model systems for biological cell migration as well as artificial micromachines. A simple and well-studied microswimmer model consists of three identical spherical beads joined by two springs in a linear fashion with active oscillatory forces being applied on the beads to generate self-propulsion. We have extended this linear microswimmer configuration to a triangular geometry where the three beads are connected by three identical springs in an equilateral triangular manner. The active forces acting on each spring can lead to autonomous steering motion; i.e., allowing the swimmer to move along arbitrary paths. We explore the microswimmer dynamics analytically and pinpoint its rich character depending on the nature of the active forces. The microswimmers can translate along a straight trajectory, rotate at a fixed location, as well as perform a simultaneous translation and rotation resulting in complex curved trajectories. The sinusoidal active forces on the three springs of the microswimmer contain naturally four operating parameters which are more than required for the steering motion. We identify the minimal operating parameters which are essential for the motion of the microswimmer along any given arbitrary trajectory. Therefore, along with providing insights into the mechanics of the complex motion of the natural and artificial microswimmers, the triangular three-bead microswimmer can be utilized as a model for targeted drug delivery systems and autonomous underwater vehicles where intricate trajectories are involved.

  16. Efficient simulation of semiflexible polymers

    NARCIS (Netherlands)

    Panja, Deb; Barkema, Gerard T.; van Leeuwen, J. M. J.

    2015-01-01

    Using a recently developed bead-spring model for semiflexible polymers that takes into account their natural extensibility, we report an efficient algorithm to simulate the dynamics for polymers like double-stranded DNA (dsDNA) in the absence of hydrodynamic interactions. The dsDNA is modeled with

  17. Polymer anion selective membranes for electrolytic splitting of water. Part I: stability of ion-exchange groups and impact of the polymer binder

    Czech Academy of Sciences Publication Activity Database

    Hnát, J.; Paidar, M.; Schauer, Jan; Žitka, Jan; Bouzek, K.

    2011-01-01

    Roč. 41, č. 9 (2011), s. 1043-1052 ISSN 0021-891X. [International Congress of Chemical and Process Engineering CHISA 2010 /19./ and European Congress of Chemical Engineering ECCE-7 /7./. Praha, 28.08.2010-01.09.2010] R&D Projects: GA MŠk(CZ) 7E08005 Institutional research plan: CEZ:AV0Z40500505 Keywords : water electrolysis * alkaline environment * polymer electrolyte Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.745, year: 2011

  18. Magnetic bead detection using nano-transformers.

    Science.gov (United States)

    Kim, Hyung Kwon; Hwang, Jong Seung; Hwang, Sung Woo; Ahn, Doyeol

    2010-11-19

    A novel scheme to detect magnetic beads using a nano-scale transformer with a femtoweber resolution is reported. We have performed a Faraday's induction experiment with the nano-transformer at room temperature. The transformer shows the linear output voltage responses to the sinusoidal input current. When magnetic beads are placed on the transformer, the output responses are increased by an amount corresponding to the added magnetic flux from the beads when compared with the case of no beads on the transformer. In this way, we could determine whether magnetic beads are on top of the transformer in a single particle level.

  19. Dynamics of competitive polymer adsorption onto planar surfaces in good solvent.

    Science.gov (United States)

    Källrot, Niklas; Linse, Per

    2010-03-25

    Adsorption of mixed polymer solutions in good solvent containing polymers of different chain length has been studied by applying simulation techniques on a coarse-grained bead-spring polymer model. Fully flexible polymers at varying bead-surface interaction strength and different combinations of flexible, semiflexible, and stiff polymers at a single bead-surface interaction strength have been examined. Monte Carlo simulation techniques have been employed to investigate static equilibrium properties and Brownian dynamic simulations to follow the dynamics of the adsorption process. The properties examined comprise the adsorbed number of polymers, adsorbed number of beads, bead density profiles, components of the polymer radius of gyration, tail, loop, and train configurations, and nematic bond order of adsorbed beads. The adsorption involves an initially independent adsorption of the two polymer types followed by competitive adsorption. The competitive adsorption is characterized by a maximum of the adsorbed amount and a desorption of the polymer with the smallest surface affinity and a continued, but reduced, growth of the adsorbed amount of the polymer with the largest surface affinity. The surface affinity difference between the two polymer types of different length increased with increasing bead-surface interaction. Furthermore, the surface affinity of a polymer initially decreased but then largely increased at increasing stiffness. As a consequence, a stiff short polymer was found to displace a 4-fold longer flexible polymer. The spatial extension of adsorbed polymers as characterized by the radius of gyration parallel and perpendicular to the surface of a polymer of a given flexibility was independent of the flexibility of the other polymer type. The fraction of beads in tails was increased and in trains reduced as the surface affinity of the dissimilar polymer type was raised. Finally, the adsorption layer of a stiff polymer possesses a nematic bond order. In

  20. Synthesis and Properties of Anion Exchangers Derived from Chloromethyl Styrene Codivinylbenzene and Their Use in Water Treatment

    Directory of Open Access Journals (Sweden)

    Hesham A. Ezzeldin

    2010-01-01

    Full Text Available Amination of vinylbenzyl chloride-divinylbenzene (VBC-DVB copolymers is an effective method for preparation of ion-exchange resins. Conventionally, the starting polymer is produced by chloromethylation of a styrene-divinylbenzene copolymer that utilizes chloromethyl methyl ether, a known carcinogen. An alterative approach is to copolymerize vinylbenzyl chloride with divinylbenzene to generate the necessary VBC-DVB. This method provides precise control over the density of the ion-exchange groups. The regiochemistry of the vinylbenzyl chloride methods was realized using solvent-ion exchange groups. In this investigation, an improved solvent system was found for the preparation of anion exchange resins by the vinylbenzyl chloride route. The effectiveness of amination of the intermediate VBC-DVB polymers with a variety of trimethylamine reagents was investigated, and ethanolic trimethylamine produced the highest degree of amination. These resulting ion-exchange polymers were characterized by a variety of techniques such as analytical titrations, nitrogen analysis, Fourier transform infrared spectroscopy and thermal gravimetric analysis. Testing of these copolymers for breakthrough was performed. The results indicate that these anion exchangers have a meaningful increase in thermal stability over commercial anionic exchange beads.

  1. Coordination Chemistry Inside Polymeric Nanoreactors: Interparticle Metal Exchange and Ionic Compound Vectorization in Phosphine-Functionalized Amphiphilic Polymer Latexes.

    Science.gov (United States)

    Chen, Si; Gayet, Florence; Manoury, Eric; Joumaa, Ahmad; Lansalot, Muriel; D'Agosto, Franck; Poli, Rinaldo

    2016-04-25

    Stable latexes of hierarchically organized core-cross-linked polymer micelles that are functionalized at the core with triphenylphosphine (TPP@CCM) have been investigated by NMR spectroscopic analysis at both natural (ca. pH 5) and strongly basic (pH 13.6) pH values after core swelling with toluene. The core-shell interface structuring forces part of the hydrophilic poly(ethylene oxide) (PEO) chains to reside inside the hydrophobic core at both pH values. Loading the particle cores with [Rh(acac)(CO)2 ] (acac=acetylacetonate) at various Rh/P ratios yielded polymer-supported [Rh(acac)(CO)(TPP)] (TPP=triphenylphosphine). The particle-to-particle rhodium migration is very fast at natural pH, but slows down dramatically at high pH, whereas the size distribution of the nanoreactors remains unchanged. The slow migration at pH 13.6 leads to the generation of polymer-anchored [Rh(OH)(CO)(TPP)2 ], which is also generated immediately upon the addition of NaOH to the particles with a [Rh(acac)(CO)] loading of 50 %. Similarly, treatment of the same particles with NaCl yielded polymer-anchored [RhCl(CO)(TPP)2 ]. Interparticle coupling occurs during these rapid processes. These experiments prove that the major contribution to metal migration is direct core-core contact. The slow migration at the high pH value, however, must result from a pathway that does not involve core-core contact. The facile penetration of the polymer cores by NaOH and NaCl results from the presence of shell-linked poly(ethylene oxide) methyl ether functions both outside and inside the polymer core-shell interface. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. In-Bead Screening of Hydroxamic Acids for the Identification of HDAC Inhibitors

    DEFF Research Database (Denmark)

    Qvortrup, Katrine; Nielsen, Thomas Eiland

    2016-01-01

    A one bead–one compound screening format is presented. Following solid-phase synthesis on a photolabile linker, library compounds were readily released and screened inside polymer beads. The release of screening compounds was readily controlled by varying photolysis time and light intensity. Dose...

  3. In‐Bead Screening of Hydroxamic Acids for the Identification of HDAC Inhibitors

    DEFF Research Database (Denmark)

    Qvortrup, Katrine; Nielsen, Thomas Eiland

    2016-01-01

    A one bead–one compound screening format is presented. Following solid‐phase synthesis on a photolabile linker, library compounds were readily released and screened inside polymer beads. The release of screening compounds was readily controlled by varying photolysis time and light intensity. Dose...

  4. Rational design on controlled release ion-exchange polymeric microspheres and polymer-lipid hybrid nanoparticles for the delivery of water-soluble drugs through a multidisciplinary approach

    Science.gov (United States)

    Li, Yongqiang

    Sulfopropyl dextran sulfate (SP-DS) microspheres and polymer-lipid hybrid nanoparticles (PLN) for the delivery of water-soluble anticancer drugs and P-glycoprotein inhibitors were developed by our group recently and demonstrated effectiveness in local chemotherapy. To optimize the delivery performance of these particulate systems, particularly PLN, an integrated multidisciplinary approach was developed, based on an in-depth understanding of drug-excipient interactions, internal structure, drug loading and release mechanisms, and application of advanced modeling/optimization techniques. An artificial neural networks (ANN) simulator capable of formulation optimization and drug release prediction was developed. In vitro drug release kinetics of SP-DS microspheres, with various drug loading and in different release media, were predicted by ANN. The effects of independent variables on drug release were evaluated. Good modeling performance suggested that ANN is a useful tool to predict drug release from ion-exchange microspheres. To further improve the performance of PLN, drug-polymer-lipid interactions were characterized theoretically and experimentally using verapamil hydrochloride (VRP) as a model drug and dextran sulfate sodium (DS) as a counter-ion polymer. VRP-DS complexation followed a stoichiometric rule and solid-state transformation of VRP were observed. Dodecanoic acid (DA) was identified as the lead lipid carrier material. Based upon the optimized drug-polymer-lipid interactions, PLN with high drug loading capacity (36%, w/w) and sustained release without initial burst release were achieved. VRP remained amorphous and was molecularly dispersed within PLN. H-bonding contributed to the miscibility between the VRP-DS complex and DA. Drug release from PLN was mainly controlled by diffusion and ion-exchange processes. Drug loading capacity and particle size of PLN depend on the formulation factors of the weight ratio of drug to lipid and concentrations of

  5. Selective permeation of moisture and VOCs through polymer membranes used in total heat exchangers for indoor air ventilation.

    Science.gov (United States)

    Zhang, L-Z; Zhang, X-R; Miao, Q-Z; Pei, L-X

    2012-08-01

    Fresh air ventilation is central to indoor environmental control. Total heat exchangers can be key equipment for energy conservation in ventilation. Membranes have been used for total heat exchangers for more than a decade. Much effort has been spent to achieve water vapor permeability of various membranes; however, relatively little attention has been paid to the selectivity of moisture compared with volatile organic compounds (VOCs) through such membranes. In this investigation, the most commonly used membranes, both hydrophilic and hydrophobic ones, are tested for their permeability for moisture and five VOCs (acetic acid, formaldehyde, acetaldehyde, toluene, and ethane). The selectivity of moisture vs. VOCs in these membranes is then evaluated. With a solution-diffusion model, the solubility and diffusivity of moisture and VOCs in these membranes are calculated. The resulting data could provide some reference for future material selection. Total heat exchangers are important equipment for fresh air ventilation with energy conservation. However, their implications for indoor air quality in terms of volatile organic compound permeation have not been known. The data in this article help us to clarify the impacts on indoor VOC levels of membrane-based heat exchangers. Guidelines for material selection can be obtained for future use total heat exchangers for building ventilation. © 2011 John Wiley & Sons A/S.

  6. Polymer and bitumen-modified OPC for the immobilization of ILW

    International Nuclear Information System (INIS)

    Johnson, D.I.; Worrall, G.; Phillips, D.C.

    1986-01-01

    A detailed study has been made of the modification of ordinary Portland cement with polymeric additives, and of the properties of waste forms based on these matrix materials. The additives were styrene butadiene and bitumen emulsions, and epoxide and polyurethane resins: the simulated wastes were organic ion exchanger beads, PWR evaporator concentrate, reprocessing concentrate and Magnox metal. The effect of polymer: cement (p:c) and water:cement ratios on the properties of the hardened cement paste has been comprehensively investigated. Substantial increases in strain to failure, and modest reductions in permeability to water and leach rates for Cs 137 , are obtained at p:c > 0.2. Much larger volume fractions of organic ion exchange beads can be encapsulated in polymer modified OPC than in unmodified OPC, perhaps because of their better strain capability. The radiation stability of cemented PWR evaporator concentrate is better for a polymer-modified matrix than an unmodified OPC matrix. Two hundred litre trials have been successfully demonstrated. 20 refs, 20 tabs, 10 figs

  7. Chelating polymeric beads as potential therapeutics for Wilson's disease.

    Science.gov (United States)

    Mattová, Jana; Poučková, Pavla; Kučka, Jan; Skodová, Michaela; Vetrík, Miroslav; Stěpánek, Petr; Urbánek, Petr; Petřík, Miloš; Nový, Zbyněk; Hrubý, Martin

    2014-10-01

    Wilson's disease is a genetic disorder caused by a malfunction of ATPase 7B that leads to high accumulation of copper in the organism and consequent toxic effects. We propose a gentle therapy to eliminate the excessive copper content with oral administration of insoluble non-resorbable polymer sorbents containing selective chelating groups for copper(II). Polymeric beads with the chelating agents triethylenetetramine, N,N-di(2-pyridylmethyl)amine, and 8-hydroxyquinoline (8HQB) were investigated. In a preliminary copper uptake experiment, we found that 8HQB significantly reduced copper uptake (using copper-64 as a radiotracer) after oral administration in Wistar rats. Furthermore, we measured organ radioactivity in rats to demonstrate that 8HQB radiolabelled with iodine-125 is not absorbed from the gastrointestinal tract after oral administration. Non-resorbability and the blockade of copper uptake were also confirmed with small animal imaging (PET/CT) in mice. In a long-term experiment with Wistar rats fed a diet containing the polymers, we have found that there were no signs of polymer toxicity and the addition of polymers to the diet led to a significant reduction in the copper contents in the kidneys, brains, and livers of the rats. We have shown that polymers containing specific ligands could potentially be novel therapeutics for Wilson's disease. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Rapid Detection of Enterobacter Sakazakii in milk Powder using amino modified chitosan immunomagnetic beads.

    Science.gov (United States)

    Zhu, Yinglian; Wang, Dongfeng

    2016-12-01

    Chitosan immunomagnetic beads (CIBs) were first prepared through converting hydroxyl groups of natural polymer material-chitosan into amino groups using epichlorohydrin and ethylenediamine as modification agent and then coupling with polyclonal antibodies of Enterobacter sakazakii using glutaraldehyde as cross-linking agent. The beads before coupling with antibodies were characterized by magnetic property measurement, FTIR, SEM and XRD technologies. In the assay a natural polysaccharide-chitosan, which has good biological and chemical properties such as non-toxicity, biocompatibility and high chemical reactivity was first used for synthesis of immunomagnetic beads. The detection method first established in this paper that combined the beads with chromogenic medium together to rapid detect E. sakazakii in milk powder could greatly improve the detection specificity and working efficiency. The beads exhibited a maximum capturing capacity of 1×10 6 cfu/g with the detection sensitivity of 4cfu/g. The results demonstrate that the assay is a straightforward, specific and sensitive alternative for rapid detection of E.sakazakii in food matrix. The total analysis time was as little as about 25h, which greatly shorten the detection time. The method can provides new ideas not only to preparation technique of immunomagnetic beads but to imunne detection technique in food safety. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Development of Expanded Thermoplastic Polyurethane Bead Foams and Their Sintering Mechanism

    Science.gov (United States)

    Hossieny, Nemat

    Polymer bead foaming technology represents a breakthrough in the production of low density plastic foamed components that have a complex geometrical structure and has helped to expand the market for plastic foams by broadening their applications. In this research, the unique microstructure of thermoplastic polyurethane (TPU) consisting of phase-separated hard segment (HS) domains dispersed in the soft segment (SS) matrix has been utilized to develop expanded TPU (E-TPU) bead foam with microcellular morphologies and also to create inter-bead sintering into three dimensional products using steam-chest molding machine. The phase-separation and crystallization behavior of the HS chains in the TPU microstructure was systematically studied in the presence of dissolved gases and also by changing the microstructure of TPU by melt-processing and addition of nano-/micro-sized additives. It was observed that the presence of gas improved the phase separation (i.e. crystallization) of HSs and increased the overall crystallinity of the TPU. It was also shown that by utilizing the HS crystalline domains, the overall foaming behavior of TPU (i.e. cell nucleation and expansion ratio) can be significantly improved. Moreover, the HS crystalline domains can be effective for both sintering of the beads as well strengthening the individual beads to improve the property of the moulded part. It was also observed that unlike other polymer bead foaming technologies, the E-TPU bead foaming sintering does not require formation of double melting-peak. The original broad melting peak existing in the TPU microstructure due to the wide size distribution of HS crystallites can be effectively utilized for the purpose of sintering as well as maintenance of the overall dimensional stability of the moulded part.

  10. Geochemical features of glass beads excavated from the Iron Age archaeological sites, Eastern Taiwan

    Science.gov (United States)

    Yang, H.

    2016-12-01

    The uses of metallic artifacts began 2500-2000 years ago in Taiwan; in the meanwhile glass beads have also been as a common ornament by the prehistoric people. Glass, as the earliest artificial ornament, is made by a mixture of quartz sands and flux which were heated to more than one thousand Celsius degrees. Therefore, the production processes, raw material provenance and exchange systems could be revealed by the chemical compositions of glass artifacts. The chemical composition of glass beads studies from four archaeological sites (PL, PN, CHL and TL sites) in early Iron Age are reported in this study. By the producing in drawn method and limited ranges of colors with various hue, all the studied glass beads here should be classified as Indo-Pacific glass beads. As these ancient glass beads are unique and precious, a non-destructive analytical method is always considered at the initial stage. Therefore, we use the best known and most widely-used of the surface analytical techniques SEM/EDX to get the surface and quantitative elemental information of glass beads. According to the analytical results, the PL and PN glass beads all belong to potassium silica glass and those coexisting with so-called Kueishan sherds excavated from CHL and TL sites should be classified as sodium-calcium glass which is the most general composition of Indo-Pacific glass beads. Not only the different flux using between potassium and sodium glass, the variation in the aluminum contents between potassium and sodium glass also exhibits different provenances of glass-making raw materials. As lack of glass-making remains in Taiwan, these ancient glass beads were considered as a precious and trading artifact to Taiwan from overseas and introduced into prehistoric societies via various sources and paths. Although the trading/exchange routes of ancient glass beads are still debatable, we find that compositional analyses can help answer such questions as what types of glass were used for their

  11. Fenugreek seed mucilage-alginate mucoadhesive beads of metformin HCl: Design, optimization and evaluation.

    Science.gov (United States)

    Nayak, Amit Kumar; Pal, Dilipkumar; Pradhan, Jyotiprakash; Hasnain, M Saquib

    2013-03-01

    The work investigates the development and optimization of fenugreek (Trigonella foenum-graecum L.) seed mucilage (FSM)-alginate mucoadhesive beads containing metformin HCl through ionotropic gelation using 3(2) factorial design. The effect of polymer-blend ratio (sodium alginate to FSM) and cross-linker (CaCl(2)) concentration on the drug encapsulation efficiency (DEE, %), and cumulative drug release after 10h (R(10h), %) was optimized. The DEE (%) of all these beads was within the range of 71.63 ± 2.32 to 95.08 ± 3.73% with sustained in vitro drug release of 69.78 ± 2.43% to 95.70 ± 4.26% over 10h. The in vitro drug release from these beads was followed controlled-release (zero-order) pattern (R(2)=0.9910 to 0.9953) with super case-II transport mechanism. The average size of these beads was within the range of 0.92 ± 0.05 to 1.30 ± 0.14 mm. The beads were also characterized by SEM, FTIR and (1)H NMR. The swelling and degradation of FSM-alginate beads containing metformin HCl were influenced by pH of the test medium. These beads also exhibited good mucoadhesivity in wash-off test. The optimized FSM-alginate mucoadhesive beads containing metformin HCl showed significant hypoglycemic effect in alloxan-induced diabetic rats over prolonged period after oral administration. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Bifunctional groups grafted polyethersulfone magnetic beads for selective sequestration of plutonium

    International Nuclear Information System (INIS)

    Paul, Sumana; Aggarwal, S.K.; Pandey, A.K.

    2014-01-01

    The present study involves synthesis of polyethersulfone (PES) beads grafted with two different monomers viz. 2-hydroxyethylmethacrylate phosphoric acid ester (HEMP) and 2-acrylamido-2-methyl-1-propane sulphonic acid (AMPS) by photo-induced free radical polymerization method. The selection of bifunctional polymer was based on our previous studies, which indicated its efficacy for selective preconcentration of Pu from 3-4 mol L -1 HNO 3 . The HEMP-co-AMPS grafted PES beads were used for selective extraction of plutonium from dissolver solution

  13. Expanded polylactide bead foaming - A new technology

    Science.gov (United States)

    Nofar, M.; Ameli, A.; Park, C. B.

    2015-05-01

    Bead foaming technology with double crystal melting peak structure has been recognized as a promising method to produce low-density foams with complex geometries. During the molding stage of the bead foams, the double peak structure generates a strong bead-to-bead sintering and maintains the overall foam structure. During recent years, polylactide (PLA) bead foaming has been of the great interest of researchers due to its origin from renewable resources and biodegradability. However, due to the PLA's low melt strength and slow crystallization kinetics, the attempts have been limited to the manufacturing methods used for expanded polystyrene. In this study, for the first time, we developed microcellular PLA bead foams with double crystal melting peak structure. Microcellular PLA bead foams were produced with expansion ratios and average cell sizes ranging from 3 to 30-times and 350 nm to 15 µm, respectively. The generated high melting temperature crystals during the saturation significantly affected the expansion ratio and cell density of the PLA bead foams by enhancing the PLA's poor melt strength and promoting heterogeneous cell nucleation around the crystals.

  14. Conducting Polymers

    Indian Academy of Sciences (India)

    ized the plastics industry by providing a route to polypropylene. (Zeigler and Natta jointly won the. Nobel Prize in Chemistry in 1963 for their discovery.) ... transport of charge in these systems can be understood in a simple fashion, by causing the imine and amine nitrogens to exchange places along the polymer backbone (in ...

  15. Conducting Polymers

    Indian Academy of Sciences (India)

    the plastics industry by providing a route to polypropylene. (Zeigler and Natta jointly won the Nobel Prize in chemistry in 1963 for their discovery.) ... these systems can be understood in a simple fashion, by causing the imine and amine nitrogens to exchange places along the polymer backbone (in protonated emeraldinel.

  16. Colorimetric detection and removal of radioactive Co ions using sodium alginate-based composite beads

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Daigeun; Jo, Ara [Organic and Optoelectronic Materials Laboratory, Department of Organic Materials Engineering, Chungnam National University, Daejeon 34134 (Korea, Republic of); Yang, Hee-Man; Seo, Bum-Kyoung; Lee, Kune-Woo [Decontamination and Decommissioning Research Division, Korea Atomic Energy Research Institute, Daejeon 34057 (Korea, Republic of); Lee, Taek Seung, E-mail: tslee@cnu.ac.kr [Organic and Optoelectronic Materials Laboratory, Department of Organic Materials Engineering, Chungnam National University, Daejeon 34134 (Korea, Republic of)

    2017-03-15

    Highlights: • Organic/inorganic hybridized alginate beads were newly synthesized via sol-gel chemistry. • Interaction between the azopyridine and metal ion is the main cause of Co ion detection. • The beads showed improved stability and least leakage of azopyridine during use. • Removal of Co ion was assessed by the ion-exchange of carboxylate groups in alginate. • The beads with dual functions of detection and removal of Co ion were successfully accomplished. - Abstract: We demonstrate a simple method for the visual determination and removal of Co ions using a bead-shaped, capturing probe based on hybridized sodium alginate. For Co ions, the designed protocol consisted of three main constituents: an azopyridine-based Co ion-probe for visual detection; sodium alginate as an adsorbent for the Co ion and a bead construct for removal and structure; silica as a linker for the probe and the alginate, leading to a robust structure. When the composite beads were exposed to Co ions, the yellow color of the beads turned to intensive violet and the color intensity was associated with the Co ion concentration. The color variation was quantified using red-green-blue (RGB) color values that were obtained with a scanner and evaluated with Photoshop. The technique achieved both visual recognition with obvious color change of the beads and efficient removal of the radioactive {sup 60}Co ion. The sensing and removal of any radioactive isotope could be achieved with an appropriate sensing probe, to provide a simple and universal platform for remediation.

  17. Colorimetric detection and removal of radioactive Co ions using sodium alginate-based composite beads

    International Nuclear Information System (INIS)

    Kim, Daigeun; Jo, Ara; Yang, Hee-Man; Seo, Bum-Kyoung; Lee, Kune-Woo; Lee, Taek Seung

    2017-01-01

    Highlights: • Organic/inorganic hybridized alginate beads were newly synthesized via sol-gel chemistry. • Interaction between the azopyridine and metal ion is the main cause of Co ion detection. • The beads showed improved stability and least leakage of azopyridine during use. • Removal of Co ion was assessed by the ion-exchange of carboxylate groups in alginate. • The beads with dual functions of detection and removal of Co ion were successfully accomplished. - Abstract: We demonstrate a simple method for the visual determination and removal of Co ions using a bead-shaped, capturing probe based on hybridized sodium alginate. For Co ions, the designed protocol consisted of three main constituents: an azopyridine-based Co ion-probe for visual detection; sodium alginate as an adsorbent for the Co ion and a bead construct for removal and structure; silica as a linker for the probe and the alginate, leading to a robust structure. When the composite beads were exposed to Co ions, the yellow color of the beads turned to intensive violet and the color intensity was associated with the Co ion concentration. The color variation was quantified using red-green-blue (RGB) color values that were obtained with a scanner and evaluated with Photoshop. The technique achieved both visual recognition with obvious color change of the beads and efficient removal of the radioactive 60 Co ion. The sensing and removal of any radioactive isotope could be achieved with an appropriate sensing probe, to provide a simple and universal platform for remediation.

  18. New generation of composite inorganic ion-exchangers with polyacrylonitrile binding matrix

    International Nuclear Information System (INIS)

    Sebesta, F.; John, J.; Motl, A.; Uvirova, K.; Smrckova, S.

    1998-01-01

    General procedure for treatment of powdered inorganic ion-exchangers using binding polymer - modified polyacrylonitrile (PAN) into beads suitable for the application in column packed beds was proposed earlier. These composite ion-exchangers were tested for many applications, some of them are used in the full-scale treatment of liquid radioactive wastes and/or for radioanalytical purposes. New generation of the composite ion-exchangers was developed to improve their volume exchange capacity and mechanical strength. Further, composite absorbers with new active components or their mixtures were prepared. The possibility of preparation of magnetic composite adsorbers and magnetic composite ion-exchangers was also studied. The new prepared materials were mainly tested for their application in caesium separation from highly active acidic waste streams. The efficiency of AMP-PAN (ammonium molybdophosphate active component) and ferrocyanides based composite ion-exchangers for caesium separation was studied in more details. Possibilities of regeneration of the above mentioned composite ion-exchangers were also studied. In preliminary experiments, mercury sorption from model mixed radioactive wastes onto ferro- and ferricyanide based absorbers was tested. The new generation of composite ion-exchangers with hydrated titanium oxide or sodium titanate as active component was tested for strontium separation from alkaline solutions. (author)

  19. Preparation and characterization of polymer blend based on sulfonated poly (ether ether ketone) and polyetherimide (SPEEK/PEI) as proton exchange membranes for fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Hashim, Nordiana; Ali, Ab Malik Marwan [Ionic Material and Devices Research Laboratory, Institute of Science, Universiti Teknologi MARA, 40450 Shah Alam (Malaysia); Lepit, Ajis; Rasmidi, Rosfayanti [Faculty of Applied Sciences, Universiti Teknologi MARA Sabah, Beg Berkunci 71, 88997 Kota Kinabalu (Malaysia); Subban, Ri Hanum Yahaya [Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam (Malaysia); Institute of Science, Universiti Teknologi MARA, 40450 Shah Alam (Malaysia); Yahya, Muhd Zu Azhan [Faculty of Defence Science & Technology, Universiti Pertahanan Nasional Malaysia, 57000 Kuala Lumpur (Malaysia)

    2015-08-28

    Blends of sulfonated poly (ether ether ketone) (SPEEK) and polyetherimide (PEI) were prepared in five different weight ratios using N-methyl-2-pyrrolidone (NMP) as solvent by the solution cast technique. The degree of sulfonation (DS) of the sulfonated PEEK was determined from deuterated dimethyl sulfoxide (DMSO-d{sub 6}) solution of the purified polymer using {sup 1}H NMR method. The properties studied in the present investigation includes conductivity, water uptake, thermal stability and structure analysis of pure SPEEK as well as SPEEK-PEI polymer blend membranes. The experimental results show that the conductivity of the membranes increased with increase in temperature from 30 to 80°C, except for that of pure SPEEK membrane which increased with temperature from 30 to 60°C while its conductivity decreased with increasing temperature from 60 to 80°C. The conductivity of 70wt.%SPEEK-30wt.%PEI blend membrane at 80% relative humidity (RH) is found to be 1.361 × 10{sup −3} Scm{sup −1} at 30°C and 3.383 × 10{sup −3} Scm{sup −1} at 80°C respectively. It was also found that water uptake and thermal stability of the membranes slightly improved upon blending with PEI. Structure analysis was carried out using Fourier Transform Infrared (FTIR) spectroscopy which revealed considerable interactions between sulfonic acid group of SPEEK and imide groups of PEI. Modification of SPEEK by blending with PEI shows good potential for improving the electrical and physical properties of proton exchange membranes.

  20. Oxidative degradation property of the proton-exchange membranes based on fluorinated polymer using radiation-induced grafting

    International Nuclear Information System (INIS)

    Mitani, N.; Muto, F.; Fujii, K.; Sato, Y.; Kakigi, T.; Matsuura, A.; Li Jingye; Miura, T.; Oshima, A.; Washio, M.

    2006-01-01

    To grow popularity of polymer electrolyte fuel cells (PEFCs), it is important that the life-time of FC will be evaluated. In the PEFCs operation, the oxygenated water would be produced by fuel gases crossover reaction. Moreover, the metal ions such as Fe 2+ would dissolve from piping and humidification bubblers in FC systems. As the results, the dissolved metal ions catalyze with oxygenated water, and then active oxidative radicals such as hydroxy and hydroperoxy radicals are induced by Fenton reaction. The oxidative radicals have considered one of the reasons of deterioration of FC performance. In our previous study, the partial-fluorinated sulfonic acid membranes based on crosslinked PTFE (sulfonated RX-PTFE) have been fabricated by pre EB-grafting method. In this study, in order to evaluate the chemical durability exerted on the PEFC performance of sulfonated RX-PTFE, we carried out the accelerated degradation test by Fenton reaction. The test conditions were 6 vol% H 2 O 2 with 5 ppm Fe 2+ solution at 60 degree C. The properties of sulfonated RX-PTFE before and after degradation tests were measured by means of X-ray photoelectron spectroscopy (XPS) and other methods. According to oxidative degradation test, the sulfonated RX-PTFE with higher crosslinking density of main chain became hard to deteriorate. On the contrary, the higher grafting yields became easy to degrade. It is suggested that the oxidative degradation would be greatly influenced to the grafted chain length and crosslinking density of main chain. From XPS after Fenton treated sulfonated RX-PTFE, the signal of S 2p and S 2s was disappeared. And also, by TGA and TG-MS analysis, it was found that the reduction of grafted chains was taken place. Furthermore, the crosslinked PTFE chains may be degraded through the reduction of grafted chain. The PEFC operation tests of sulfonated RX-PTFE before and after degradation tests were carried out. When the weight loss of sulfonated RX-PTFE was almost the same

  1. TETHERED-BEAD, IMMUNE SANDWICH ASSAY

    Science.gov (United States)

    Silver, Jonathan; Li, Zhenyu; Neuman, Keir

    2014-01-01

    We describe a proof-of-principal, immune sandwich assay in which immune complexes link micron-size beads via DNA tethers to a sensor surface. The number of tethered beads, counted using low-magnification microscopy, provides a measure of the concentration of analyte. The prototype assay was sensitive to pM concentration of analyte. In theory, the assay could be sensitive to sub-fM analyte because beads attached via single-immune complexes and DNA strands form tethers, and tether formation in the absence of analyte is extremely rare. The limiting step at present is binding of streptavidin at the end of DNA to biotin on capture beads. Potential advantages of this type of sensor are discussed. PMID:25064819

  2. BeadArray expression analysis using bioconductor.

    Directory of Open Access Journals (Sweden)

    Matthew E Ritchie

    2011-12-01

    Full Text Available Illumina whole-genome expression BeadArrays are a popular choice in gene profiling studies. Aside from the vendor-provided software tools for analyzing BeadArray expression data (GenomeStudio/BeadStudio, there exists a comprehensive set of open-source analysis tools in the Bioconductor project, many of which have been tailored to exploit the unique properties of this platform. In this article, we explore a number of these software packages and demonstrate how to perform a complete analysis of BeadArray data in various formats. The key steps of importing data, performing quality assessments, preprocessing, and annotation in the common setting of assessing differential expression in designed experiments will be covered.

  3. A Study of the Rheology, Processing and Flow Induced Mesostructures of Glass Bead Filled Polystyrene

    International Nuclear Information System (INIS)

    Hine, P. J.; Embery, J. E.; Tassieri, M.

    2008-01-01

    This paper presents some recent experimental results on the effects of the addition of glass beads (both coupled and uncoupled) on the linear and non-linear rheology, and hence processability, of a commercial polystyrene. Oscillatory, low strain, measurements showed an increase in viscosity with the addition of the glass beads, which varied depending on the testing frequency and degree of coupling. For the coupled beads, at low frequencies the increase in viscosity was well predicted by the Kreiger-Dougherty relationship, while at higher frequencies a smaller increase than this was seen, linked with a shift to lower frequencies of the lower frequency cross-over between G' and G''. For the uncoupled beads, the viscosity was found to shift vertically with no change in the position of the G',G'' cross-over. For the non-linear shear and extension measurements, at low shear rates and low strains the increase in viscosity agreed well with the linear results, whereas at high strain rates and strains, more disparity was seen, which in non-linear extension was been linked to voiding. For non-linear shear measurements, the plateau viscosities of the pure polystyrene were found to fit the Cox-Merz rule, while the glass bead filled materials did not. The deviations in behaviour of the filled materials were found to be closely linked to the characteristic relaxation times of the polymer, particularly the reptation time τ d and the Rouse time τ R

  4. Development of calcium pectinate-tamarind seed polysaccharide mucoadhesive beads containing metformin HCl.

    Science.gov (United States)

    Nayak, Amit Kumar; Pal, Dilipkumar; Santra, Kousik

    2014-01-30

    Novel mucoadhesive beads containing metformin HCl made of low methoxy (LM) pectin-tamarind seed polysaccharide (TSP) polymer-blend was developed through ionotropic-gelation technique and optimized using 3(2) factorial design. Effects of LM pectin and TSP amounts on drug encapsulation efficiency (DEE), and cumulative drug release at 10h (R10h) were analyzed using response surface methodology. The optimized calcium pectinate-TSP beads containing metformin HCl showed DEE of 95.12 ± 4.26%, R10h of 46.53 ± 3.28%, and mean diameter of 1.93 ± 0.26 mm. The in vitro drug release from these beads was followed controlled-release (zero-order) pattern with super case-II transport mechanism. These beads were also characterized by SEM and FTIR. The optimized beads also exhibited pH-dependent swelling, good mucoadhesivity with goat intestinal mucosa and significant hypoglycemic effect in alloxan-induced diabetic rats over prolonged period after oral administration. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Development of pectinate-ispagula mucilage mucoadhesive beads of metformin HCl by central composite design.

    Science.gov (United States)

    Nayak, Amit Kumar; Pal, Dilipkumar; Santra, Kousik

    2014-05-01

    Ionotropically-gelled mucoadhesive beads of metformin HCl composed of low methoxy (LM) pectin-ispaghula husk mucilage (IHM) polymer-blend was developed and optimized using central composite design (spherical type, single center point, and α=1.414). Effects of LM pectin and IHM amounts on drug encapsulation efficiency (DEE) and cumulative drug release at 10h (R10h) were analysed using response surface methodology. The optimized beads containing metformin HCl (F-O) showed DEE of 86.98 ± 3.26% and R10h of 47.20 ± 1.28%. All these beads exhibited suitable controlled in vitro sustained drug release pattern with super case-II transport mechanism over 10h. These beads were also characterized by SEM and FTIR. The optimized beads also exhibited pH-dependent swelling, good mucoadhesivity with goat intestinal mucosa and significant hypoglycemic effect in alloxan-induced diabetic rats over prolonged period after oral administration, which could possibly be lucrative in terms of prolonged systemic absorption of metformin HCl maintaining tight blood glucose level and advanced patient compliance. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Chiral resolution of salbutamol in plasma sample by a new chiral ligand-exchange chromatography method after its extraction with nano-sized imprinted polymer.

    Science.gov (United States)

    Alizadeh, Taher; Shamkhali, Amir Naser

    2016-01-15

    A new chromatographic procedure, based upon chiral ligand-exchange principal, was developed for the resolution of salbutamol enantiomers. The separation was carried out on a C18 column. (l)-Alanine and Cu(2+) were applied as chiral resolving agent and complexing ion, respectively. The kind of copper salt had definitive effect on the enantioseparation. Density functional theory (DFT) was used to substantiate the effect of various anions, accompanying Cu(2+), on the formation of ternary complexes, assumed to be created during separation process. The DFT results showed that the anion kind had huge effect on the stability difference between two corresponding diastereomeric complexes and their chemical structures. It was shown that the extent of participation of the chiral selector in the ternary diastereomeric complexes formation was managed by the anion kind, affecting thus the enantioseparation efficiency of the developed method. Water/methanol (70:30) mixture containing (l)-alanine-Cu(2+) (4:1) was found to be the best mobile phase for salbutamol enantioseparation. In order to analyze sulbutamol enantiomers in plasma samples, racemic salbutamol was first extracted from the samples via nano-sized salbutamol-imprinted polymer and then enantioseparated by the developed method. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Blood Compatibility of Sulfonated Cladophora Nanocellulose Beads

    Directory of Open Access Journals (Sweden)

    Igor Rocha

    2018-03-01

    Full Text Available Sulfonated cellulose beads were prepared by oxidation of Cladophora nanocellulose to 2,3-dialdehyde cellulose followed by sulfonation using bisulfite. The physicochemical properties of the sulfonated beads, i.e., high surface area, high degree of oxidation, spherical shape, and the possibility of tailoring the porosity, make them interesting candidates for the development of immunosorbent platforms, including their application in extracorporeal blood treatments. A desired property for materials used in such applications is blood compatibility; therefore in the present work, we investigate the hemocompatibility of the sulfonated cellulose beads using an in vitro whole blood model. Complement system activation (C3a and sC5b-9 levels, coagulation activation (thrombin-antithrombin (TAT levels and hemolysis were evaluated after whole blood contact with the sulfonated beads and the results were compared with the values obtained with the unmodified Cladophora nanocellulose. Results showed that neither of the cellulosic materials presented hemolytic activity. A marked decrease in TAT levels was observed after blood contact with the sulfonated beads, compared with Cladophora nanocellulose. However, the chemical modification did not promote an improvement in Cladophora nanocellulose hemocompatibility in terms of complement system activation. Even though the sulfonated beads presented a significant reduction in pro-coagulant activity compared with the unmodified material, further modification strategies need to be investigated to control the complement activation by the cellulosic materials.

  8. Blood Compatibility of Sulfonated Cladophora Nanocellulose Beads.

    Science.gov (United States)

    Rocha, Igor; Lindh, Jonas; Hong, Jaan; Strømme, Maria; Mihranyan, Albert; Ferraz, Natalia

    2018-03-07

    Sulfonated cellulose beads were prepared by oxidation of Cladophora nanocellulose to 2,3-dialdehyde cellulose followed by sulfonation using bisulfite. The physicochemical properties of the sulfonated beads, i.e., high surface area, high degree of oxidation, spherical shape, and the possibility of tailoring the porosity, make them interesting candidates for the development of immunosorbent platforms, including their application in extracorporeal blood treatments. A desired property for materials used in such applications is blood compatibility; therefore in the present work, we investigate the hemocompatibility of the sulfonated cellulose beads using an in vitro whole blood model. Complement system activation (C3a and sC5b-9 levels), coagulation activation (thrombin-antithrombin (TAT) levels) and hemolysis were evaluated after whole blood contact with the sulfonated beads and the results were compared with the values obtained with the unmodified Cladophora nanocellulose. Results showed that neither of the cellulosic materials presented hemolytic activity. A marked decrease in TAT levels was observed after blood contact with the sulfonated beads, compared with Cladophora nanocellulose. However, the chemical modification did not promote an improvement in Cladophora nanocellulose hemocompatibility in terms of complement system activation. Even though the sulfonated beads presented a significant reduction in pro-coagulant activity compared with the unmodified material, further modification strategies need to be investigated to control the complement activation by the cellulosic materials.

  9. The defouling of membranes using polymer beads containing ...

    African Journals Online (AJOL)

    2010-10-12

    Oct 12, 2010 ... steel part of the plant to the cell using 1 000 kPa flexible pipes and very convenient snap-in connections. Therefore this system limited the testing to low pressure membranes, designed for brackish water. In this plant the pressure was measured at the input of the cell and the flow rate after the throttling valve ...

  10. 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

  11. Molecularly Imprinted Polymers Chitosan-Glutaraldehyde for Monosodium Glutamate

    Science.gov (United States)

    Mulyasuryani, Ani; Haryanto, Edi; Sulistyarti, Hermin; Rumhayati, Barlah

    2018-01-01

    Chitosan has been used as a functional monomer in the synthesis of molecularly imprinted polymers (MIP) for monosodium glutamate (MSG). MIP is made from a mixture of 5 g chitosan, 50 mg glutaraldehyde and 2 g MSG, MIP is formed as flakes and beads. MIPs are identified by the FTIR spectrum, SEM image and their adsorption capabilities. MIP flakes and beads have no structural differences if they are based on FTIR or SEM spectra, but MIP adsorption capacity of beads higher than flakes. Adsorption capacity of MIP flakes is 548 mg/g and MIP beads 627 mg/g.

  12. Chelating polymeric beads as potential therapeutics for Wilson’s disease

    Czech Academy of Sciences Publication Activity Database

    Mattová, J.; Poučková, P.; Kučka, Jan; Škodová, Michaela; Vetrík, Miroslav; Štěpánek, Petr; Urbánek, P.; Petřík, M.; Nový, Z.; Hrubý, Martin

    2014-01-01

    Roč. 62, 1 October (2014), s. 1-7 ISSN 0928-0987 R&D Projects: GA ČR GAP304/12/0950; GA ČR GA13-08336S; GA MPO FR-TI4/625 Institutional support: RVO:61389013 Keywords : Wilson’s disease * polymer beads * chelators Subject RIV: CA - Inorganic Chemistry Impact factor: 3.350, year: 2014

  13. Alginate gel-coated oil-entrapped alginate-tamarind gum-magnesium stearate buoyant beads of risperidone.

    Science.gov (United States)

    Bera, Hriday; Boddupalli, Shashank; Nandikonda, Sridhar; Kumar, Sanoj; Nayak, Amit Kumar

    2015-01-01

    A novel alginate gel-coated oil-entrapped calcium-alginate-tamarind gum (TG)-magnesium stearate (MS) composite floating beads was developed for intragastric risperidone delivery with a view to improving its oral bioavailability. The TG-blended alginate core beads containing olive oil and MS as low-density materials were accomplished by ionotropic gelation technique. Effects of polymer-blend ratio (sodium alginate:TG) and crosslinker (CaCl2) concentration on drug entrapment efficiency (DEE, %) and cumulative drug release after 8 h (Q8h, %) were studied to optimize the core beads by a 3(2) factorial design. The optimized beads (F-O) exhibited DEE of 75.19±0.75% and Q8h of 78.04±0.38% with minimum errors in prediction. The alginate gel-coated optimized beads displayed superior buoyancy and sustained drug release property. The drug release profiles of the drug-loaded uncoated and coated beads were best fitted in Higuchi kinetic model with Fickian and anomalous diffusion driven mechanisms, respectively. The optimized beads yielded a notable sustained drug release profile as compared to marketed immediate release preparation. The uncoated and coated Ca-alginate-TG-MS beads were also characterized by SEM, FTIR and P-XRD analyses. Thus, the newly developed alginate-gel coated oil-entrapped alginate-TG-MS composite beads are suitable for intragastric delivery of risperidone over a prolonged period of time. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. The Beads of Translation: Using Beads to Translate mRNA into a Polypeptide Bracelet

    Science.gov (United States)

    Dunlap, Dacey; Patrick, Patricia

    2012-01-01

    During this activity, by making beaded bracelets that represent the steps of translation, students simulate the creation of an amino acid chain. They are given an mRNA sequence that they translate into a corresponding polypeptide chain (beads). This activity focuses on the events and sites of translation. The activity provides students with a…

  15. Rheology of dilute polymer solutions with time-dependent screening of hydrodynamic interactions

    OpenAIRE

    Lisy, V.; Tothova, J.; Brutovsky, B.

    2007-01-01

    The screening of hydrodynamic interactions (HI) essentially affects macroscopic properties of polymeric solutions. This screening depends not only on the polymer concentration but has a dynamic nature. In the present work, a bead-spring theory is developed, in which this phenomenon is described for solutions of nonentangled polymer coils. The equation of motion for the beads of a test polymer is solved together with the Brinkman's equation for the solvent velocity that takes into account the ...

  16. Microwave-assisted grafting polymerization modification of nylon 6 capillary-channeled polymer fibers for enhanced weak cation exchange protein separations

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Liuwei; Marcus, R. Kenneth, E-mail: marcusr@clemson.edu

    2017-02-15

    A weak cation exchange liquid chromatography stationary phase (nylon-COOH) was prepared by grafting polyacrylic acid on to native nylon 6 capillary-channeled polymer (C-CP) fibers via a microwave-assisted radical polymerization. To the best of our knowledge, this is the first study of applying microwave-assisted grafting polymerization to affect nylon material for protein separation. The C-CP fiber surfaces were characterized by attenuated total reflection (ATR) infrared spectroscopy and scanning electron microscope (SEM). The anticipated carbonyl peak at 1722.9 cm{sup −1} was found on the nylon-COOH fibers, but was not found on the native fiber, indicating the presence of the polyacrylic acid on nylon fibers after grafting. The nylon-COOH phase showed a ∼12× increase in lysozyme dynamic binding capacity (∼12 mg mL{sup −1}) when compared to the native fiber phase (∼1 mg mL{sup −1}). The loading capacity of the nylon-COOH phase is nearly independent of the lysozyme loading concentration (0.05–1 mg mL{sup −1}) and the mobile phase linear velocity (7.3–73 mm s{sup −1}). The reproducibility of the lysozyme recovery from the nylon-COOH (RSD = 0.3%, n = 10) and the batch-to-batch variability in the functionalization (RSD = 3%, n = 5) were also investigated, revealing very high levels of consistency. Fast baseline separations of myoglobin, α-chymotrypsinogen A, cytochrome c and lysozyme were achieved using the nylon-COOH column. It was found that a 5× increase in the mobile phase linear velocity (7.3-to-36.5 mm s{sup −1}) had little effect on the separation resolution. The microwave-assisted grafting polymerization has great potential as a generalized surface modification methodology across the applications of C-CP fibers. - Highlights: • A microwave-assisted grafting method to attach acrylic acid is described for the first time for chromatographic phases. • A high-density, weak cation exchange surface is created on a nylon

  17. Aerogel Beads as Cryogenic Thermal Insulation System

    Science.gov (United States)

    Fesmire, J. E.; Augustynowicz, S. D.; Rouanet, S.; Thompson, Karen (Technical Monitor)

    2001-01-01

    An investigation of the use of aerogel beads as thermal insulation for cryogenic applications was conducted at the Cryogenics Test Laboratory of NASA Kennedy Space Center. Steady-state liquid nitrogen boiloff methods were used to characterize the thermal performance of aerogel beads in comparison with conventional insulation products such as perlite powder and multilayer insulation (MLI). Aerogel beads produced by Cabot Corporation have a bulk density below 100 kilograms per cubic meter (kg/cubic m) and a mean particle diameter of 1 millimeter (mm). The apparent thermal conductivity values of the bulk material have been determined under steady-state conditions at boundary temperatures of approximately 293 and 77 kelvin (K) and at various cold vacuum pressures (CVP). Vacuum levels ranged from 10(exp -5) torr to 760 torr. All test articles were made in a cylindrical configuration with a typical insulation thickness of 25 mm. Temperature profiles through the thickness of the test specimens were also measured. The results showed the performance of the aerogel beads was significantly better than the conventional materials in both soft-vacuum (1 to 10 torr) and no-vacuum (760 torr) ranges. Opacified aerogel beads performed better than perlite powder under high-vacuum conditions. Further studies for material optimization and system application are in progress.

  18. Alginate-okra gum blend beads of diclofenac sodium from aqueous template using ZnSO4 as a cross-linker.

    Science.gov (United States)

    Sinha, Priyanka; Ubaidulla, U; Hasnain, M Saquib; Nayak, Amit Kumar; Rama, Bobba

    2015-08-01

    Zinc (Zn(2+))-ion induced diclofenac sodium (DS)-loaded alginate-okra (Hibiscus esculentus) gum (OG) blend beads was successfully formulated through Zn(2+)-ion induced ionic-gelation cross-linking method in a complete aqueous environment. Effects of polymer-blend ratio and cross-linker concentration on drug encapsulation efficiency (DEE) and cumulative drug release at 8 h (R8h) were optimized by 3(2)-factorial design. The optimized formulation of Zn(2+)-ion induced DS-loaded alginate-OG beads demonstrated 89.27±3.58% of DEE and 43.73±2.83% of R8h. The bead sizes were within 1.10±0.07 to 1.38±0.14 mm. The bead surface morphology was analyzed by SEM. The drug-polymer interaction in the optimized bead matrix was analyzed by FTIR and P-XRD. These beads exhibited sustained in vitro drug release over a prolonged period of 8h and followed controlled-release (zero-order) pattern with super case-II transport mechanism. The swelling and degradation of the optimized beads was influenced by the pH of test mediums, which might be suitable for intestinal drug delivery. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Solid phase extraction of actinides using graphene oxide beads

    International Nuclear Information System (INIS)

    Gujar, R.B.; Mohapatra, P.K.

    2014-01-01

    Separation of actinide ions from dilute nitric acid feed solutions is important from radioactive waste remediation point of view. A large number of separation methods are available in the literature using methods such as precipitation, ion-exchange, solvent extraction, etc. Graphene oxide (GO) are reported to be a very good sorbent for actinide ions from weakly acidic feed solutions. However, it is difficult to handle GO fine particles and any chromatographic separation is bound to be difficult as the sorbent material may be finely dispersed in the aqueous phase. It was thus thought of interest to prepare GO-based resin materials in polyether sulphone (PES) by phase inversion technique. Preparation of resins by phase inversion technique has been found to be quite efficient for metal ion separation including actinide ions. In the present work, GO based PES resin beads were prepared by phase inversion technique and the uptake of actinide and lanthanide ions. In the present work, GO based beads were prepared by phase inversion technique and the uptake of actinide and lanthanide ions (such as Am(III), Eu(III), Th(IV), Pu(IV) and U(VI)) has been studied using radiotracers

  20. Looking for new hybrid polymer fillers: synthesis of nanosized α-type Zr(IV) organophosphonates through an unconventional topotactic anion exchange reaction.

    Science.gov (United States)

    Pica, Monica; Donnadio, Anna; Troni, Elisabetta; Capitani, Donatella; Casciola, Mario

    2013-07-01

    Gels of α-type zirconium(IV) phosphate alkylphosphonates, ZP(Cn)x, were prepared by reacting, at room temperature, propanol intercalated nanosized α-zirconium phosphate (α-ZrP) with propanol solutions of alkylphosphonic acids (H2Cn, n = number of carbon atoms in the alkyl chain = 4, 5, 6), with (H2Cn/Zr) molar ratios in the range 0.4-4.0. (31)P MAS NMR showed the presence of resonances due to the phosphate and phosphonate groups bonded to the Zr atoms mainly by three oxygen atoms, as in the α-type layer. The composition of the ZP(Cn)x materials, obtained by thermogravimetric analysis, ranges from x ≈ 0.2 to x ≈ 1.1. On the basis of the NMR data and of the analysis of the X-ray patterns of gels and powders, it is inferred that the ZP(Cn)x compounds have an α-type layered structure and that the reaction between α-ZrP and H2Cn is a topotactic anion exchange process. The evolution of the X-ray patterns during propanol deintercalation is consistent with a random distribution of the alkylphosphonate groups on the α-type layers which gives rise to porous pathways in the interlayer region. To test the possibility of using ZP(Cn)x as mechanical reinforcement of a polymer matrix, a starch membrane filled with 5 wt % ZP(C6)0.54 was prepared and characterized by stress-strain mechanical tests. Besides an excellent flexibility, this membrane exhibited a proportional increase of the Young's modulus by 230% in comparison with neat starch.

  1. Immobilization of Aspergillus niger F7-02 Lipase in Polysaccharide Hydrogel Beads of Irvingia gabonensis Matrix.

    Science.gov (United States)

    Kareem, Safaradeen Olateju; Adio, Olayinka Quadri; Osho, Michael Bamitale

    2014-01-01

    The potential of polysaccharide Irvingia gabonensis matrix as enzyme immobilization support was investigated. Lipase of Aspergillus niger F7-02 was immobilized by entrapment using glutaraldehyde as the cross-linking agent and stabilized in ethanolic-formaldehyde solution. The pH and temperature stability and activity yield of the immobilized enzyme were determined. Such parameters as enzyme load, bead size, number of beads, and bead reusability were also optimized. Adequate gel strength to form stabilized beads was achieved at 15.52% (w/v) Irvingia gabonensis powder, 15% (v/v) partially purified lipase, 2.5% (v/v) glutaraldehyde, and 3 : 1 (v/v) ethanolic-formaldehyde solution. There was 3.93-fold purification when the crude enzyme was partially purified in two-step purification using Imarsil and activated charcoal. Optimum lipase activity 75.3 Ug(-1) was achieved in 50 mL test solution containing 15 beads of 7 mm bead size. Relative activity 80% was retained at eight repeated cycles. The immobilization process gave activity yield of 59.1% with specific activity of 12.3 Umg(-1) and stabilized at optimum pH 4.5 and temperature 55°C. Thus the effectiveness and cost-efficiency of I. gabonensis as a polymer matrix for lipase immobilization have been established.

  2. Immobilization of Aspergillus niger F7-02 Lipase in Polysaccharide Hydrogel Beads of Irvingia gabonensis Matrix

    Directory of Open Access Journals (Sweden)

    Safaradeen Olateju Kareem

    2014-01-01

    Full Text Available The potential of polysaccharide Irvingia gabonensis matrix as enzyme immobilization support was investigated. Lipase of Aspergillus niger F7-02 was immobilized by entrapment using glutaraldehyde as the cross-linking agent and stabilized in ethanolic-formaldehyde solution. The pH and temperature stability and activity yield of the immobilized enzyme were determined. Such parameters as enzyme load, bead size, number of beads, and bead reusability were also optimized. Adequate gel strength to form stabilized beads was achieved at 15.52% (w/v Irvingia gabonensis powder, 15% (v/v partially purified lipase, 2.5% (v/v glutaraldehyde, and 3 : 1 (v/v ethanolic-formaldehyde solution. There was 3.93-fold purification when the crude enzyme was partially purified in two-step purification using Imarsil and activated charcoal. Optimum lipase activity 75.3 Ug−1 was achieved in 50 mL test solution containing 15 beads of 7 mm bead size. Relative activity 80% was retained at eight repeated cycles. The immobilization process gave activity yield of 59.1% with specific activity of 12.3 Umg−1 and stabilized at optimum pH 4.5 and temperature 55°C. Thus the effectiveness and cost-efficiency of I. gabonensis as a polymer matrix for lipase immobilization have been established.

  3. Direct friction measurement in draw bead testing

    DEFF Research Database (Denmark)

    Olsson, David Dam; Bay, Niels; Andreasen, Jan Lasson

    2005-01-01

    have been reported in literature. A major drawback in all these studies is that friction is not directly measured, but requires repeated measurements of the drawing force with and without relative sliding between the draw beads and the sheet material. This implies two tests with a fixed draw bead tool......-in piezoelectric torque transducer. This technique results in a very sensitive measurement of friction, which furthermore enables recording of lubricant film breakdown as function of drawing distance. The proposed test is validated in an experimental investigation of the influence of lubricant viscosity...

  4. Chromium (VI) ion adsorption by grafted cross-linked chitosan beads in aqueous solution - a mathematical and statistical modeling study.

    Science.gov (United States)

    Igberase, E; Osifo, P; Ofomaja, A

    2017-12-01

    Chitosan outstanding qualities and efficient way of binding metal ions even to near zero concentration is the major reason for special attention. Modification of chitosan allows the polymer to be applied in numerous field of research. Depending on the modification techniques, chitosan possesses increased adsorption capacity. In this study chitosan beads (CS) were formulated from chitosan flakes, the beads were cross-linked with glutaraldehyde and thereafter grafted with ethyldiaminetetraacetic acid. The stability and amine concentration of the beads were determined. The chemical functionalities of the beads were obtained by Fourier transform infrared spectroscopy, X-ray diffraction and thermogravimetric analysis (TGA). However, in the adsorption studies with Cr(VI), the number of runs in the experiment was obtained by response surface methodology (RSM), and the maximum adsorption capacity (Q m ) from each run was determined from the Langmuir model. The results of the experiment showed that the non-modified beads were soluble at pH 1-4 and insoluble at pH 5, while the modified beads were insoluble at pH 1-6. The amine concentration of CS, CCS and grafted cross-linked chitosan beads (GCCS) were 4.4, 3.8 and 5.0 mmol/g, respectively. The point of zero charge (pH PZC ) of GCCS was found to be 4.4. The quadratic model was significant and adequate in describing the experimental data. The difference between experimental and predicted Q m was negligible. From the design matrix and results, increased Q m was achieved at pH 5, contact time 70 min, temperature 45°C, adsorbent dosage 5 g and initial concentration 70 mg/l. The desorption of the beads loaded with Cr(VI) was successful with 0.5 M HCl eluant and contact time of 180 min, leading to cost minimization.

  5. Beads from Inhumation Rite Burials of Gnezdovo Burial Mound

    Directory of Open Access Journals (Sweden)

    Dobrova Olga P.

    2017-12-01

    Full Text Available The beads from 33 inhumation burials at Gnezdovo burial mound are examined in the article. The beads (total 367 were crafted from stretched tube (258, stretched stick (3, winding (45, press molding (2 pcs., welding (2 pcs., and mosaic beads (9 pcs.. The burial mound contains virtually no broken beads, including the settlement's most common yellow glass beads. Besides glass beads, cornelian, crystal, amber and faience beads have been registered among the burial mound material, as well as beads crafted with metal. Apart from beads, grave inventories contained a series of pendants with a bead strung on a wire ring. The considered complexes contain five pendants of this type. Besides Gnezdovo, similar pendants have been discovered in Kiev, Timerev, Pskov and Vladimir barrows. A comparison between bead sets from Gnezdovo and Kiev burial mounds allows to conclude that the general composition and occurrence frequency of beads is identical for these burials. At the same time, beads crafted with rock crystal, cornelian and metal are more frequently discovered in Kiev inhumations.

  6. Polymers in separation processes

    Science.gov (United States)

    Wieszczycka, Karolina; Staszak, Katarzyna

    2017-05-01

    Application of polymer materials as membranes and ion-exchange resins was presented with a focus on their use for the recovery of metal ions from aqueous solutions. Several membrane techniques were described including reverse osmosis, nanofiltration, ultrafiltration, diffusion and Donnan dialysis, electrodialysis and membrane extraction system (polymer inclusion and supported membranes). Moreover, the examples of using ion-exchange resins in metal recovery were presented. The possibility of modification of the resin was discussed, including hybrid system with metal cation or metal oxide immobilized on polymer matrices or solvent impregnated resin.

  7. Gel bead composition for metal adsorption

    Science.gov (United States)

    Scott, Charles D.; Woodward, Charlene A.; Byers, Charles H.

    1990-01-01

    The invention is a gel bead comprising propylene glycol alginate and bone gelatin and is capable of removing metals such as Sr and Cs from solution without adding other adsorbents. The invention could have application to the nuclear industry's waste removal activities.

  8. Wood mimetic hydrogel beads for enzyme immobilization.

    Science.gov (United States)

    Park, Saerom; Kim, Sung Hee; Won, Keehoon; Choi, Joon Weon; Kim, Yong Hwan; Kim, Hyung Joo; Yang, Yung-Hun; Lee, Sang Hyun

    2015-01-22

    Wood component-based composite hydrogels have potential applications in biomedical fields owing to their low cost, biodegradability, and biocompatibility. The controllable properties of wood mimetic composites containing three major wood components are useful for enzyme immobilization. Here, lipase from Candida rugosa was entrapped in wood mimetic beads containing cellulose, xylan, and lignin by dissolving wood components with lipase in [Emim][Ac], followed by reconstitution. Lipase entrapped in cellulose/xylan/lignin beads in a 5:3:2 ratio showed the highest activity; this ratio is very similar to that in natural wood. The lipase entrapped in various wood mimetic beads showed increased thermal and pH stability. The half-life times of lipase entrapped in cellulose/alkali lignin hydrogel were 31- and 82-times higher than those of free lipase during incubation under denaturing conditions of high temperature and low pH, respectively. Owing to their biocompatibility, biodegradability, and controllable properties, wood mimetic hydrogel beads can be used to immobilize various enzymes for applications in the biomedical, bioelectronic, and biocatalytic fields. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Fungal cultivation on glass-beads

    DEFF Research Database (Denmark)

    Droce, Aida; Sørensen, Jens Laurids; Giese, Henriette

    Transcription of various bioactive compounds and enzymes are dependent on fungal cultivation method. In this study we cultivate Fusarium graminearum and Fusarium solani on glass-beads with liquid media in petri dishes as an easy and inexpensive cultivation method, that resembles in secondary...

  10. Analysis of Bead Sizes for MR Capsules Labeled for Sprinkle

    OpenAIRE

    Nagavelli, Laxma R.; Lionberger, Robert A.; Sayeed, Vilayat A.; Yu, Lawrence; Allgire, James; Smith, Anjanette; Wokovich, Anna; Westenberger, Benjamin J.; Buhse, Lucinda

    2010-01-01

    The bead sizes used in approved modified release capsules labeled for sprinkling on food was investigated to generate bead size guidelines for generic products labeled for sprinkling. The conclusions from a survey of FDA databases were corroborated with experimental data obtained by measuring the bead sizes of several reference-listed drugs on the market labeled for administration by sprinkling on food. The experimental data show that majority of the marketed products were found to have bead ...

  11. New Nanoparticles Dispersing Beads Mill with Ultra Small Beads and its Application

    International Nuclear Information System (INIS)

    Inkyo, M; Tahara, T; Imajyo, Y

    2011-01-01

    Two of the major problems related to nanoparticle dispersion with a conventional beads mill are re-agglomeration and damage to the crystalline structure of the particles. The Ultra Apex Mill was developed to solve these problems by enabling the use of ultra-small beads with a diameter of less than 0.1mm. The core of this breakthrough development is centrifugation technology which allows the use of beads as small as 0.015mm. When dispersing agglomerated nanoparticles the impulse of the small beads is very low which means there is little influence on the particles. The surface energy of the nanoparticles remains low so the properties are not likely to change. As a result, stable nanoparticle dispersions can be achieved without re-cohesion. The Ultra Apex Mill is superior to conventional beads mills that are limited to much larger bead sizes. The technology of the Ultra Apex Mill has pioneered practical applications for nanoparticles in various fields: composition materials for LCD screens, ink-jet printing, ceramic condensers and cosmetics.

  12. Compressive and Tensile Strength of Expanded Polystyrene Beads Concrete

    OpenAIRE

    Subhan, Tengku Fitriani L

    2005-01-01

    Penelitian ini betujuan untuk mempelajari property dari beton ringan yang mengandung expanded polystyrene beads, yaitu kuat tekan (compressive strength) dan kuat tarik (tensile strength). Property tersebut kemudian dibandingkan dengan beton normal (beton tanpa expanded polystyrene beads) sebagai campuran pengontrol. Hasil penelitian ini menunjukkan bahwa jumlah polystyrene beads yang dimasukkan sebagai campuran beton mempengaruhi property beton; yaitu dapat menurunkan kuat tekan beton. Tetapi...

  13. Assessment of the Problems of Manual Automobile Tyre Bead ...

    African Journals Online (AJOL)

    The tyre-rim bead bond must be broken to carry out repairs on a failed automobile tyre. The use of the locally fabricated manual bead breaking equipment as it is being practiced today by commercial tyre repair artisans in Nigeria is characterized by drudgery. This article reports a study of the local manual bead breaking ...

  14. A Controlled Drug-Delivery Experiment Using Alginate Beads

    Science.gov (United States)

    Farrell, Stephanie; Vernengo, Jennifer

    2012-01-01

    This paper describes a simple, cost-effective experiment which introduces students to drug delivery and modeling using alginate beads. Students produce calcium alginate beads loaded with drug and measure the rate of release from the beads for systems having different stir rates, geometries, extents of cross-linking, and drug molecular weight.…

  15. Toward a Mesoscale Model for the Dynamics of Polymer Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Miller, G H; Trebotich, D

    2006-10-02

    To model entire microfluidic systems containing solvated polymers we argue that it is necessary to have a numerical stability constraint governed only by the advective CFL condition. Advancements in the treatment of Kramers bead-rod polymer models are presented to enable tightly-coupled fluid-particle algorithms in the context of system-level modeling.

  16. Osmotic pressure of ring polymer solutions : A Monte Carlo study

    NARCIS (Netherlands)

    Flikkema, Edwin; Brinke, Gerrit ten

    2000-01-01

    Using the wall theorem, the osmotic pressure of ring polymers in solution has been determined using an off-lattice topology conserving Monte Carlo algorithm. The ring polymers are modeled as freely-jointed chains with point-like beads, i.e., under conditions corresponding to θ-conditions for the

  17. Synthesis and properties of the metallo-supramolecular polymer hydrogel poly[methyl vinyl ether-alt-mono-sodium maleate]·AgNO3: Ag+/Cu2+ ion exchange and effective antibacterial activity

    KAUST Repository

    Xu, Feng

    2014-01-01

    The commercial polymeric anhydride poly(methyl vinyl ether-alt-maleic anhydride) (PVM/MA) is converted by reaction with NaOH to give poly(methyl vinyl ether-alt-mono-sodium maleate) (PVM/Na-MA). By addition of AgNO 3-solution, the formation of the silver(i) supramolecular polymer hydrogel poly[methyl vinyl ether-alt-mono-sodium maleate]·AgNO 3 is reported. Freeze-dried samples of the hydrogel show a mesoporous network of polycarboxylate ligands that are crosslinked by silver(i) cations. In the intact hydrogel, ion-exchange studies are reported and it is shown that Ag+ ions can be exchanged by copper(ii) cations without disintegration of the hydrogel. The silver(i) hydrogel shows effective antibacterial activity and potential application as burn wound dressing. © the Partner Organisations 2014.

  18. Biosorption of americium by alginate beads

    International Nuclear Information System (INIS)

    Borba, Tania Regina de; Marumo, Julio Takehiro; Goes, Marcos Maciel de; Ferreira, Rafael Vicente de Padua; Sakata, Solange Kazumi

    2009-01-01

    The use of biotechnology to remove heavy metals from wastes plays great potential in treatment of radioactive wastes and therefore the aim of this study was to evaluate the biosorption of americium by alginate beads. Biosorption has been defined as the property of certain biomolecules to bind and remove selected ions or other molecules from aqueous solutions. The calcium alginate beads as biosorbent were prepared and analyzed for americium uptaking. The experiments were performed in different solution activity concentrations, pH and exposure time. The results suggest that biosorption process is more efficient at pH 4 and for 75, 150, 300 Bq/mL and 120 minutes were necessary to remove almost 100% of the americium-241 from the solution. (author)

  19. A novel adjuvant: polymerised serum albumin beads

    International Nuclear Information System (INIS)

    Dewar, J.B.

    1985-09-01

    There is an ongoing need to develop new vaccine formulations. To complement accumulating knowledge on the structure of antigens and their interaction with cells of the immune system, new vaccine vehicles to optimise the immunogenic potential of the antigen must be developed. Associated with this adjuvanticity, should be minimal adverse side effects. This study was initiated to develop a vaccine vehicle, consisting of covalently cross-linked serum albumin beads, themselves non-immunogenic, containing virus. Following inoculation, in vivo proteolysis of the beads would allow a gradual release of antigen for sustained immunostimulation. This system might have application in virus vaccine programmes to improve low immunogenic vaccines, to allow optimal delivery of the recently derived synthetic virus subunit peptides as well as for inactivated virus vaccine preparations. 35 S-methionine labelled Blue Tongue Virus was used in this study

  20. Green stone beads at the dawn of agriculture

    Science.gov (United States)

    Bar-Yosef Mayer, Daniella E.; Porat, Naomi

    2008-01-01

    The use of beads and other personal ornaments is a trait of modern human behavior. During the Middle and Upper Paleolithic periods, beads were made out of shell, bone, ivory, egg shell, and occasionally of minerals. During the transition to agriculture in the Near East, stone, in particular green stone, was used for the first time to make beads and pendants. We observed that a large variety of minerals of green colors were sought, including apatite, several copper-bearing minerals, amazonite and serpentinite. There seems to be an increase with time of distance from which the green minerals were sought. Because beads in white, red, yellow, brown, and black colors had been used previously, we suggest that the occurrence of green beads is directly related to the onset of agriculture. Green beads and bead blanks were used as amulets to ward off the evil eye and as fertility charms. PMID:18559861

  1. Stress Relaxation in Entangled Polymer Melts

    DEFF Research Database (Denmark)

    Hou, Ji-Xuan; Svaneborg, Carsten; Everaers, Ralf

    2010-01-01

    We present an extensive set of simulation results for the stress relaxation in equilibrium and step-strained bead-spring polymer melts. The data allow us to explore the chain dynamics and the shear relaxation modulus, G(t), into the plateau regime for chains with Z=40 entanglements and into the t...

  2. Metallurgical investigation of wire breakage of tyre bead grade

    Directory of Open Access Journals (Sweden)

    Piyas Palit

    2015-10-01

    Full Text Available Tyre bead grade wire is used for tyre making application. The wire is used as reinforcement inside the polymer of tyre. The wire is available in different size/section such as 1.6–0.80 mm thin Cu coated wire. During tyre making operation at tyre manufacturer company, wire failed frequently. In this present study, different broken/defective wire samples were collected from wire mill for detailed investigation of the defect. The natures of the defects were localized and similar in nature. The fracture surface was of finger nail type. Crow feet like defects including button like surface abnormalities were also observed on the broken wire samples. The defect was studied at different directions under microscope. Different advanced metallographic techniques have been used for detail investigation. The analysis revealed that, white layer of surface martensite was formed and it caused the final breakage of wire. In this present study we have also discussed about the possible reason for the formation of such kind of surface martensite (hard-phase.

  3. HPMA and HEMA copolymer bead interactions with eukaryotic cells

    Directory of Open Access Journals (Sweden)

    Cristina D. Vianna-Soares

    2004-09-01

    Full Text Available Two different hydrophilic acrylate beads were prepared via aqueous suspension polymerization. Beads produced of a hydroxypropyl methacrylate (HPMA and ethyleneglycol methacrylate (EDMA copolymer were obtained using a polyvinyl alcohol suspending medium. Copolymers of 2hydroxyethyl methacrylate (HEMA, methyl methacrylate (MMA and ethyleneglycol methacrylate (EDMA beads were obtained using magnesium hydroxide as the suspending agent. Following characterization by scanning electron microscopy (SEM, nitrogen sorption analysis (NSA and mercury intrusion porosimetry (MIP, the beads were cultured with monkey fibroblasts (COS7 to evaluate their ability to support cell growth, attachment and adhesion. Cell growth behavior onto small HPMA/EDMA copolymer beads and large HEMA/MMA/EDMA copolymer beads is evaluated regarding their hidrophilicity/hidrophobicity and surface roughness.

  4. Detection of ''beading faults'' in welded tubes

    International Nuclear Information System (INIS)

    Mondot, J.

    In the steel tube industry the word ''beading'' refers to a highly localised leak affecting the welded zone. During the pneumatic test its flow rate is generally very low no more than a few thousandths of a mm 3 /second. Detection of such a fault by this test is consequently slow, and those which are choked or at the limit of leakage may escape detection. For greater safety, the tube technician is now using non-destructive testing methods such as eddy-currents and ultrasonics [fr

  5. Immobilization in cement of ion exchange resins from Spanish nuclear reactors

    International Nuclear Information System (INIS)

    Huebra, A.G. de la; Murillo, R.; Ortiz, S.J.

    1990-01-01

    Ion exchange materials used at nuclear power plants can be immobilized in cements less expensive than polymer matrices. Cement solidification of spent ion exchange resins shows swelling and cracking troubles (during setting time, or of storage). The objective of this study was to select the types of cement that produce the best quality on immobilization of three kinds of resins and to set up cement formulations containing the maximum possible loading of resin. Four cements were selected to carried out the study. After a study of hydration-dehydration phenomena of ion exchange resins, a systematic work has been carried out on immobilization. Tests were performed to study compressive strength and underwater stability by changing water/cement ratio and resin/cement ratio. Mixtures made with water, cement and resin only were loaded with 10% by weight dry resin. Mixtures with higher loadings show poor workability. Tests were carried out by adding organic plasticizers and silica products to improve waste loading. Plasticizers reduced water demand and silica products permit the use of more water. Leaching tests have been performed at 40 O C. In conclusion Blast Furnace Slag is the best cement for immobilization of ion exchange resin both bead and powdered form for mechanical strength, stability and leaching

  6. Polymer films

    Science.gov (United States)

    Granick, Steve; Sukhishvili, Svetlana A.

    2004-05-25

    A film contains a first polymer having a plurality of hydrogen bond donating moieties, and a second polymer having a plurality of hydrogen bond accepting moieties. The second polymer is hydrogen bonded to the first polymer.

  7. Experimental study of porous media flow using hydro-gel beads and LED based PIV

    Science.gov (United States)

    Harshani, H. M. D.; Galindo-Torres, S. A.; Scheuermann, A.; Muhlhaus, H. B.

    2017-01-01

    A novel experimental approach for measuring porous flow characteristics using spherical hydro-gel beads and particle image velocimetry (PIV) technique is presented. A transparent porous medium consisting of hydro-gel beads that are made of a super-absorbent polymer, allows using water as the fluid phase while simultaneously having the same refractive index. As a result, a more adaptable and cost effective refractive index matched (RIM) medium is created. The transparent nature of the porous medium allows optical systems to visualize the flow field by using poly-amide seeding particles (PSP). Low risk light emitting diode (LED) based light was used to illuminate the plane in order to track the seeding particles’ path for the characterization of the flow inside the porous medium. The system was calibrated using a manually measured flow by a flow meter. Velocity profiles were obtained and analysed qualitatively and quantitatively in order to characterise the flow. Results show that this adaptable, low risk experimental set-up can be used for flow measurements in porous medium under low Reynolds numbers. The limitations of using hydro-gel beads are also discussed.

  8. Porous Ceramic Spheres from Ion Exchange Resin

    Science.gov (United States)

    Dynys, Fred

    2005-01-01

    A commercial cation ion exchange resin, cross-linked polystyrene, has been successfully used as a template to fabricate 20 to 50 micron porous ceramic spheres. Ion exchange resins have dual template capabilities. Pore architecture of the ceramic spheres can be altered by changing the template pattern. Templating can be achieved by utilizing the internal porous structure or the external surface of the resin beads. Synthesis methods and chemical/physical characteristics of the ceramic spheres will be reported.

  9. Creating nanoshell on the surface of titanium hydride bead

    Directory of Open Access Journals (Sweden)

    PAVLENKO Vyacheslav Ivanovich

    2016-12-01

    Full Text Available The article presents data on the modification of titanium hydride bead by creating titanium nanoshell on its surface by ion-plasma vacuum magnetron sputtering. To apply titanium nanoshell on the titanium hydride bead vacuum coating plant of multifunctional nanocomposite coatings QVADRA 500 located in the center of high technology was used. Analysis of the micrographs of the original surface of titanium hydride bead showed that the microstructure of the surface is flat, smooth, in addition the analysis of the microstructure of material surface showed the presence of small porosity, roughness, mainly cavities, as well as shallow longitudinal cracks. The presence of oxide film in titanium hydride prevents the free release of hydrogen and fills some micro-cracks on the surface. Differential thermal analysis of both samples was conducted to determine the thermal stability of the initial titanium hydride bead and bead with applied titanium nanoshell. Hydrogen thermal desorption spectra of the samples of the initial titanium hydride bead and bead with applied titanium nanoshell show different thermal stability of compared materials in the temperature range from 550 to 860о C. Titanium nanoshells applied in this way allows increasing the heat resistance of titanium hydride bead – the temperature of starting decomposition is 695о C and temperature when decomposition finishes is more than 1000о C. Modified in this way titanium hydride bead can be used as a filler in the radiation protective materials used in the construction or upgrading biological protection of nuclear power plants.

  10. Brownian dynamics of wall tethered polymers in shear flow

    Science.gov (United States)

    Lin, Tiras Y.; Saadat, Amir; Kushwaha, Amit; Shaqfeh, Eric S. G.

    2017-11-01

    The dynamics of a wall tethered polymer in shear flow is studied using Brownian dynamics. Simulations are performed with bead-spring chains, and the effect of hydrodynamic interactions (HI) is incorporated through Blake's tensor with a finite size bead correction. We characterize the configuration of the polymer as a function of the Weissenberg number by investigating the regions the polymer explores in both the flow-gradient and flow-vorticity planes. The fractional extension in the flow direction, the width in the vorticity direction, and the thickness in the gradient direction are reported as well, and these quantities are found to compare favorably with the experimental data of the literature. The cyclic motion of the polymer is demonstrated through analysis of the mean velocity field of the end bead. We characterize the collision process of each bead with the wall as a Poisson process and extract an average wall collision rate, which in general varies along the backbone of the chain. The inclusion of HI with the wall for a tethered polymer is found to reduce the average wall collision rate. We anticipate that results from this work will be directly applicable to, e.g., the design of polymer brushes or the use of DNA for making nanowires in molecular electronics. T.Y.L. is supported by the Department of Defense (DoD) through the National Defense Science & Engineering Graduate Fellowship (NDSEG) Program.

  11. Heavy and toxic metal uptake by mesoporous hypercrosslinked SMA beads: Isotherms and kinetics

    Directory of Open Access Journals (Sweden)

    Renuka Gonte

    2016-09-01

    Full Text Available Hypercrosslinked styrene-maleic acid copolymer beads were used for the removal of metal ions from mimicked industrial effluents. The polymer was characterized by SEM which revealed the presence of a porous network. Carboxyl acid groups of the polymer were identified as active sites for metal uptake. Highly porous surface enhanced metal ion uptake was achieved through a physicochemical process. Equilibrium sorption of metal ions was best described by the Freundlich and Temkin model with R2 > 0.99. Adsorption followed pseudo first and pseudo second order reaction kinetics. Intraparticle diffusion model suggested a three step equilibrium. Desorption was a fast process with ∼90% in 60 min.

  12. Pu Anion Exchange Process Intensification

    Energy Technology Data Exchange (ETDEWEB)

    Taylor-Pashow, Kathryn M. L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-10-06

    This research is focused on improving the efficiency of the anion exchange process for purifying plutonium. While initially focused on plutonium, the technology could also be applied to other ion-exchange processes. Work in FY17 focused on the improvement and optimization of porous foam columns that were initially developed in FY16. These foam columns were surface functionalized with poly(4-vinylpyridine) (PVP) to provide the Pu specific anion-exchange sites. Two different polymerization methods were explored for maximizing the surface functionalization with the PVP. The open-celled polymeric foams have large open pores and large surface areas available for sorption. The fluid passes through the large open pores of this material, allowing convection to be the dominant mechanism by which mass transport takes place. These materials generally have very low densities, open-celled structures with high cell interconnectivity, small cell sizes, uniform cell size distributions, and high structural integrity. These porous foam columns provide advantages over the typical porous resin beads by eliminating the slow diffusion through resin beads, making the anion-exchange sites easily accessible on the foam surfaces. The best performing samples exceeded the Pu capacity of the commercially available resin, and also offered the advantage of sharper elution profiles, resulting in a more concentrated product, with less loss of material to the dilute heads and tails cuts. An alternate approach to improving the efficiency of this process was also explored through the development of a microchannel array system for performing the anion exchange.

  13. Polymer-supported reagents with enhanced metal ion recognition: Application to separations science

    International Nuclear Information System (INIS)

    Alexandratos, S.D.

    1993-01-01

    The design and development of polymer-supported reagents with ever-increasing specificities for targeted metal ions remains an important areas of research. The need for efficient separation schemes for both ions and molecules has been outlined in a report by the National Research Council (King) and will gain increased emphasis as environmental restoration is pursued. Polymer-supported reagents are unique in their ability to be applied in an environmentally benign manner to a host of challenges. Such reagents, in the form of beads, can be applied to continuous separation processes ranging from the removal of metal ions in water to the recovery of medicinal drugs produced through biotechnological means. The application of polymer-supported reagents to metal ion separations still requires developing a fundamental understanding of ligand-metal interactions, the role of the polymer in those interactions, and the methods of synthesizing such polymeric reagents in a readily applicable form. Ion exchange resins with sulfonic acid ligands are the prototypical polymer-supported reagents, and their properties have been exhaustively studied (Helfferich). The high acidity of the sulfonic acid group, however, precludes much selectivity, and it displays a very limited range of reaction free energy values with different metal ions (Boyd et al.). The carboxylic acid ligand, present in the acrylate resins, is more selective, though its weak acidity requires relatively high pH solutions for it to be effective. Research has thus been focused on the preparation of polymer-supported reagents with high levels of specificity for targeted metal ions

  14. Considerations in binding diblock copolymers on hydrophilic alginate beads for providing an immunoprotective membrane

    Science.gov (United States)

    Spasojevic, Milica; Bhujbal, Swapnil; Paredes, Genaro; de Haan, Bart J; Schouten, Arend J; de Vos, Paul

    2014-01-01

    Alginate-based microcapsules are being proposed for treatment of many types of diseases. A major obstacle however in the successes is that these capsules are having large lab-to-lab variations. To make the process more reproducible, we propose to cover the surface of alginate capsules with diblock polymers that can form polymer brushes. In the present study, we describe the stepwise considerations for successful application of diblock copolymer of polyethylene glycol (PEG) and poly-l-lysine (PLL) on the surface of alginate beads. Special procedures had to be designed as alginate beads are hydrophilic and most protocols are designed for hydrophobic biomaterials. The successful attachment of diblock copolymer and the presence of PEG blocks on the surface of the capsules were studied by fluorescence microscopy. Longer time periods, that is, 30–60 min, are required to achieve saturation of the surface. The block lengths influenced the strength of the capsules. Shorter PLL blocks resulted in less stable capsules. Adequate permeability of the capsules was achieved with poly(ethylene glycol)-block-poly(l-lysine hydrochloride) (PEG454-b-PLL100) diblock copolymers. The capsules were a barrier for immunoglobulin G. The PEG454-b-PLL100 capsules have similar mechanical properties as PLL capsules. Minor immune activation of nuclear factor κB in THP-1 monocytes was observed with both PLL and PEG454-b-PLL100 capsules prepared from purified alginate. Our results show that we can successfully apply block copolymers on the surface of hydrophilic alginate beads without interfering with the physicochemical properties. PMID:23853069

  15. Development of pH-sensitive tamarind seed polysaccharide-alginate composite beads for controlled diclofenac sodium delivery using response surface methodology.

    Science.gov (United States)

    Nayak, Amit Kumar; Pal, Dilipkumar

    2011-11-01

    The present study deals with the development of novel pH-sensitive tamarind seed polysaccharide (TSP)-alginate composite beads for controlled diclofenac sodium delivery using response surface methodology by full 3(2) factorial design. The effect of polymer-blend ratio (sodium alginate:TSP) and cross-linker (CaCl(2)) concentration on the drug encapsulation efficiency (DEE, %) and drug release from diclofenac sodium loaded TSP-alginate composite beads prepared by ionotropic gelation was optimized. The observed responses were coincided well with the predicted values by the experimental design. The DEE (%) of these beads containing diclofenac sodium was within the range between 72.23±2.14 and 97.32±4.03% with sustained in vitro drug release (69.08±2.36-96.07±3.54% in 10 h). The in vitro drug release from TSP-alginate composite beads containing diclofenac sodium was followed by controlled-release pattern (zero-order kinetics) with case-II transport mechanism. Particle size range of these beads was 0.71±0.03-1.33±0.04 mm. The swelling and degradation of the developed beads were influenced by different pH of the test medium. The FTIR and NMR analyses confirmed the compatibility of the diclofenac sodium with TSP and sodium alginate used to prepare the diclofenac sodium loaded TSP-alginate composite beads. The newly developed TSP-alginate composite beads are suitable for controlled delivery of diclofenac sodium for prolonged period. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. exploring traditional glass bead making techniques in jewellery

    African Journals Online (AJOL)

    User

    Decorations with glass beads communicate cultural values in a symbolic lan- guage which expresses status, ... enced by environmental factors. Fitch (1992) traces the history of glass bead making from Western Asia and ... these two areas with similar characteristics from the accessible areas which give a true reflection of ...

  17. The risks of gastrointestinal injury due to ingested magnetic beads ...

    African Journals Online (AJOL)

    The risks of gastrointestinal injury due to ingested magnetic beads. S Cox, R Brown, A Millar, A Numanoglu, A Alexander, A Theron. Abstract. Accidental ingestion of foreign bodies is a common problem in children. Magnetic bead toys are hazardous, having potentially lethal consequences if ingested. These magnets ...

  18. Middle stone age shell beads from South Africa

    CSIR Research Space (South Africa)

    Henshilwood, C

    2004-04-16

    Full Text Available undisputed African personal ornaments are 13 ostrich eggshell beads from Enkapune Ya Muto in Kenya similar to 40 ka. Evidence from Eurasia includes two perforated teeth, dated similar to 43 ka, from Bacho Kiro in Bulgaria and 58 marine shell beads from...

  19. Towards a programmable magnetic bead microarray in a microfluidic channel

    DEFF Research Database (Denmark)

    Smistrup, Kristian; Bruus, Henrik; Hansen, Mikkel Fougt

    2007-01-01

    to use larger currents and obtain forces of longer range than from thin current lines at a given power limit. Guiding of magnetic beads in the hybrid magnetic separator and the construction of a programmable microarray of magnetic beads in the microfluidic channel by hydrodynamic focusing is presented....

  20. Bead Collage: An Arts-Based Research Method

    Science.gov (United States)

    Kay, Lisa

    2013-01-01

    In this paper, "bead collage," an arts-based research method that invites participants to reflect, communicate and construct their experience through the manipulation of beads and found objects is explained. Emphasizing the significance of one's personal biography and experiences as a researcher, I discuss how my background as an…

  1. Growth and morphology of thermophilic dairy starters in alginate beads.

    Science.gov (United States)

    Lamboley, Laurence; St-Gelais, Daniel; Champagne, Claude P; Lamoureux, Maryse

    2003-06-01

    The aim of this research was to produce concentrated biomasses of thermophilic lactic starters using immobilized cell technology (ICT). Fermentations were carried out in milk using pH control with cells microentrapped in alginate beads. In the ICT fermentations, beads represented 17% of the weight. Some assays were carried out with free cells without pH control, in order to compare the ICT populations with those of classical starters. With Streptococcus thermophilus, overall populations in the fermentor were similar, but maximum bead population for (8.2 x 10(9) cfu/g beads) was 13 times higher than that obtained in a traditional starter (4.9 x 10(8) cfu/ml). For both Lactobacillus helveticus strains studied, immobilized-cell populations were about 3 x 10(9) cfu/g beads. Production of immobilized Lb. bulgaricus 210R strain was not possible, since no increases in viable counts occurred in beads. Therefore, production of concentrated cell suspension in alginate beads was more effective for S. thermophilus. Photomicrographs of cells in alginate beads demonstrated that, while the morphology of S. thermophilus remained unchanged during the ICT fermentation, immobilized cells of Lb. helveticus appeared wider. In addition, cells of Lb. bulgaricus were curved and elongated. These morphological changes would also impair the growth of immobilized lactobacilli.

  2. Superparamagnetic bead interactions with functionalized surfaces characterized by an immunomicroarray

    DEFF Research Database (Denmark)

    Skottrup, Peter Durand; Hansen, Mikkel Fougt; Moresco, Jacob Lange

    2010-01-01

    Magneto-resistive sensors capable of detecting superparamagnetic micro-/nano-sized beads are promising alternatives to standard diagnostic assays based on absorbance or fluorescence and streptavidin-functionalized beads are widely used as an integral part of these sensors. Here we have developed ...

  3. Configurational Statistics of Magnetic Bead Detection with Magnetoresistive Sensors

    DEFF Research Database (Denmark)

    Henriksen, Anders Dahl; Ley, Mikkel Wennemoes Hvitfeld; Flyvbjerg, Henrik

    2015-01-01

    Magnetic biosensors detect magnetic beads that, mediated by a target, have bound to a functionalized area. This area is often larger than the area of the sensor. Both the sign and magnitude of the average magnetic field experienced by the sensor from a magnetic bead depends on the location of the...

  4. Bead magnetorelaxometry with an on-chip magnetoresistive sensor

    DEFF Research Database (Denmark)

    Dalslet, Bjarke Thomas; Damsgaard, Christian Danvad; Donolato, Marco

    2011-01-01

    Magnetorelaxometry measurements on suspensions of magnetic beads are demonstrated using a planar Hall effect sensor chip embedded in a microfluidic system. The alternating magnetic field used for magnetizing the beads is provided by the sensor bias current and the complex magnetic susceptibility ...

  5. Exploring Traditional Glass Bead Making Techniques in Jewellery ...

    African Journals Online (AJOL)

    Exploring Traditional Glass Bead Making Techniques in Jewellery. IK Agye, J Adu-Agyem, R Steiner. Abstract. Exploring traditional glass bead making techniques in jewellery in some prominent areas in Ghana is a means to exposing the area for metal and ceramic artists and other related fields of discipline such as ...

  6. A High-Throughput SU-8Microfluidic Magnetic Bead Separator

    DEFF Research Database (Denmark)

    Bu, Minqiang; Christensen, T. B.; Smistrup, Kristian

    2007-01-01

    We present a novel microfluidic magnetic bead separator based on SU-8 fabrication technique for high through-put applications. The experimental results show that magnetic beads can be captured at an efficiency of 91 % and 54 % at flow rates of 1 mL/min and 4 mL/min, respectively. Integration of s...

  7. 21 CFR 173.20 - Ion-exchange membranes.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ion-exchange membranes. 173.20 Section 173.20 Food... Polymer Substances and Polymer Adjuvants for Food Treatment § 173.20 Ion-exchange membranes. Ion-exchange membranes may be safely used in the processing of food under the following prescribed conditions: (a) The...

  8. Metallic gold beads in hyaluronic acid

    DEFF Research Database (Denmark)

    Pedersen, Dan Sonne; Tran, Thao Phuong; Smidt, Kamille

    2013-01-01

    Multiple sclerosis (MS) is a neurodegenerative disease caused by recurring attacks of neuroinflammation leading to neuronal death. Immune-suppressing gold salts are used for treating connective tissue diseases; however, side effects occur from systemic spread of gold ions. This is limited...... by exploiting macrophage-induced liberation of gold ions (dissolucytosis) from gold surfaces. Injecting gold beads in hyaluronic acid (HA) as a vehicle into the cavities of the brain can delay clinical signs of disease progression in the MS model, experimental autoimmune encephalitis (EAE). This study...... investigates the anti-inflammatory properties of metallic gold/HA on the gene expression of tumor necrosis factor (Tnf-α), Interleukin (Il)-1β, Il-6, Il-10, Colony-stimulating factor (Csf)-v2, Metallothionein (Mt)-1/2, Bcl-2 associated X protein (Bax) and B cell lymphoma (Bcl)-2 in cultured J774 macrophages...

  9. Entrapment of laurel lipase in chitosan hydrogel beads.

    Science.gov (United States)

    Yagar, Hulya; Balkan, Ugur

    2017-08-01

    Laurel seed lipase was entrapped within chitosan beads with ionotropic gelatin method using tripolyphosphate (TPP) as multivalent covalent counter ion. Immobilization yield was 78%. First, optimum immobilization conditions were determined, and morphology of chitosan beads was characterized by scanning electron microscopy. Optimum pH and temperature were evaluated as 6.0 and 40 °C, respectively. The immobilized beads saved about 55% of its activities at 60° while saved about 32% at 70 °C for 30 min. V max /K m values were determined as 31.75 and 2.87 using olive oil as substrate for immobilized beads and free enzyme, respectively. Immobilized beads showed the activities during 30 days at +4 °C.

  10. Analysis of bead sizes for MR capsules labeled for sprinkle.

    Science.gov (United States)

    Nagavelli, Laxma R; Lionberger, Robert A; Sayeed, Vilayat A; Yu, Lawrence; Allgire, James; Smith, Anjanette; Wokovich, Anna; Westenberger, Benjamin J; Buhse, Lucinda

    2010-12-01

    The bead sizes used in approved modified release capsules labeled for sprinkling on food was investigated to generate bead size guidelines for generic products labeled for sprinkling. The conclusions from a survey of FDA databases were corroborated with experimental data obtained by measuring the bead sizes of several reference-listed drugs on the market labeled for administration by sprinkling on food. The experimental data show that majority of the marketed products were found to have bead sizes of less than 1,500 microm (1.5 mm). Based on this information, a bead size of less than 1,500 microm should generally be considered acceptable for use in generic products labeled for sprinkling.

  11. Influence of Silica/Sulfonated Polyether-Ether Ketone as Polymer Electrolyte Membrane for Hydrogen Fueled Proton Exchange Membrane Fuel Cells

    Directory of Open Access Journals (Sweden)

    Sri Handayani

    2011-12-01

    Full Text Available The operation of non-humidified condition of proton exchange membrane fuel cell (PEMFC using composite sPEEK-silica membrane is reported. Sulfonated membrane of PEEK is known as hydrocarbon polyelectrolyte membrane for PEMFC and direct methanol fuel cell (DMFC. The state of the art of fuel cells is based on the perluorosulfonic acid membrane (Nafion. Nafion has been the most used in both PEMFC and DMFC due to good performance although in low humidified condition showed poor current density. Here we reported the effect of silica in hydrocarbon sPEEK membrane that contributes for a better water management system inside the cell, and showed 0.16 W/cm2 of power density which is 78% higher than that of non-silica modified [Keywords: composite membrane, polyether-ether ketone, silica, proton exchange membrane fuel cell].

  12. Simultaneous detection and removal of radioisotopes with modified alginate beads containing an azo-based probe using RGB coordinates

    International Nuclear Information System (INIS)

    Jo, Ara; Jang, Geunseok; Namgung, Ho; Kim, Choongho; Kim, Daigeun; Kim, Yujun; Kim, Jongho; Lee, Taek Seung

    2015-01-01

    Highlights: • Modified alginate with azo-based probe (ABO) was synthesized by a reaction between sodium alginate and azo-based probe (BO2). • BO2 was found to be a good probe molecule for radioisotopes using colorimetric analysis. • Detection of Co 2+ and Sr 2+ was mainly carried out via interaction between BO2 and metal ions. • Simultaneous removal of radioisotopes was assessed by the ion-exchange of carboxylate groups in sodium alginate. • The alginate beads with dual functions of detection and removal of metal ions are successfully accomplished. - Abstract: We prepared alginate beads that were modified with an azo-based probe molecule to monitor simultaneously the removal (by alginate) and probing (by the azo-probe molecule) of radioisotopes such as cobalt, strontium, and cesium ions. As an azo-probe molecule, Basic Orange 2 (BO2) was immobilized to the alginate bead. The BO2 in aqueous solution exhibited a slight red shift in absorption with a change in color from orange to dark orange upon addition of cobalt and strontium ions. In contrast, the color of BO2 did not change upon exposure to cesium ions. Thus, the covalently embedded BO2 in alginate beads could adsorb cobalt and strontium ions resulting in recognizable color change of the beads, which was induced by the formation of a complex between BO2 and metal ions. The color changes of the beads in the presence of metal ions were determined quantitatively using RGB color coordinate values. In addition to effectively removing metal ions, the colorimetric coordinate method provides a convenient and simple sensing technique for naked-eye metal ion detection.

  13. Development of a new passive sampler based on diffusive milligel beads for copper analysis in water

    Energy Technology Data Exchange (ETDEWEB)

    Perez, M.; Reynaud, S.; Lespes, G.; Potin-Gautier, M. [Université de Pau et des Pays de l’Adour/CNRS UMR IPREM 5254, Hélioparc, 2 av. du Président Angot, 64053 Pau (France); Mignard, E. [CNRS-Solvay-Université Bordeaux, UMR5258, Laboratoire du Futur, 178 Avenue du Dr. A. Schweitzer, 33608 Pessac Cedex (France); Chéry, P. [Bordeaux Science Agro, 1 cours du Général De Gaulle, Gradignan, 33175 (France); Schaumlöffel, D. [Université de Pau et des Pays de l’Adour/CNRS UMR IPREM 5254, Hélioparc, 2 av. du Président Angot, 64053 Pau (France); Grassl, B., E-mail: bruno.grassl@univ-pau.fr [Université de Pau et des Pays de l’Adour/CNRS UMR IPREM 5254, Hélioparc, 2 av. du Président Angot, 64053 Pau (France)

    2015-08-26

    A new passive sampler was designed and characterized for the determination of free copper ion (Cu{sup 2+}) concentration in aqueous solution. Each sampling device was composed of a set of about 30 diffusive milligel (DMG) beads. Milligel beads with incorporated cation exchange resin (Chelex) particles were synthetized using an adapted droplet-based millifluidic process. Beads were assumed to be prolate spheroids, with a diameter of 1.6 mm and an anisotropic factor of 1.4. The milligel was controlled in chemical composition of hydrogel (monomer, cross-linker, initiator and Chelex concentration) and characterized in pore size. Two types of sampling devices were developed containing 7.5% and 15% of Chelex, respectively, and 6 nm pore size. The kinetic curves obtained demonstrated the accumulation of copper in the DMG according to the process described in the literature as absorption (and/or adsorption) and release following the Fick's first law of diffusion. For their use in water monitoring, the typical physico-chemical characteristics of the samplers, i.e. the mass-transfer coefficient (k{sub 0}) and the sampler-water partition coefficient (K{sub sw}), were determined based on a static exposure design. In order to determine the copper concentration in the samplers after their exposure, a method using DMG bead digestion combined to Inductively Coupled Plasma – Atomic Emission Spectrometry (ICP-AES) analysis was developed and optimized. The DMG devices proved to be capable to absorb free copper ions from an aqueous solution, which could be accurately quantified with a mean recovery of 99% and a repeatability of 7% (mean relative uncertainty). - Highlights: • Controlled geometry of new passive sampler with ellipsoidal shape. • Original manufacturing process based on droplet-based millifluidic device. • Pore size characterization of the sampler. • Mass-transfer and sampler-water partitioning coefficients by static exposure experiments.

  14. Immobilized OBOC combinatorial bead array to facilitate multiplicative screening

    Science.gov (United States)

    Townsend, Jared; Li, Yuanpei; Liu, Ruiwu; Lam, Kit S.

    2015-01-01

    One-bead-one-compound (OBOC) combinatorial library screening has been broadly utilized for the last two decades to identify small molecules, peptides or peptidomimetics targeting variable screening probes such as cell surface receptors, bacteria, protein kinases, phosphatases, proteases etc. In previous screening methods, library beads were suspended in solution and screened against one single probe. Only the positive beads were tracked and isolated for additional screens and finally selected for chemical decoding. During this process, the remaining negative beads were not tracked and discarded. Here we report a novel bead immobilization method such that a bead library array can be conveniently prepared and screened in its entirety, sequentially many times with a series of distinct probes. This method not only allows us to increase the screening efficiency but also permits us to determine the binding profile of each and every library bead against a large number of target receptors. As proof of concept, we serially screened a random OBOC disulfide containing cyclic heptapeptide library with three water soluble dyes as model probes: malachite green, bromocresol purple and indigo carmine. This multiplicative screening approach resulted in a rapid determination of the binding profile of each and every bead respective to each of the three dyes. Beads that interacted with malachite green only, bromocresol purple only, or both indigo carmine and bromocresol purple were isolated, and their peptide sequences were determined with microsequencer. Ultimately, the novel OBOC multiplicative screening approach could play a key role in the enhancement of existing on-bead assays such as whole cell binding, bacteria binding, protein binding, post-translational modifications etc. with increased efficiency, capacity, and specificity. PMID:23488896

  15. Dynamics of linear polymers in a microchannel fluid flow

    Science.gov (United States)

    Bose, Prasenjit; Fodor, Petru; Kaufman, Miron

    2010-10-01

    Examination of the dynamics of polymers in a fluid flow is an important topic of research because of potential biomedical applications. We simulated the motion of a linear polymer caried in a laminar fluid flow inside a rectangular channel. Our model polymer is made up of beads which are connected by springs. When the polymer is released in the fluid elastic and advection forces act on each bead. The Newton's 2nd law for each bead is integrated numerically using 4th order Runge-Kutta technique. The dynamics of this nonlinear mechanical system depends on the values of the spring equilibrium distance (a), mass of a bead (m), the initial fluid inflow constant (B), and the spring constant (k). Various trials were conducted by varying some of these parameters and the results were recorded and plotted. It was observed that the motion of the polymer was more noisy for higher values of a and k. The variation of time periods with the changing parameters was studied numerically.

  16. Energy efficient bead milling of microalgae: Effect of bead size on disintegration and release of proteins and carbohydrates

    NARCIS (Netherlands)

    Postma, P.R.; Suarez Garcia, E.; Safi, Carl; Yonathan, K.; Olivieri, G.; Barbosa, M.J.; Wijffels, R.H.; Eppink, M.H.M.

    2017-01-01

    The disintegration of three industry relevant algae (Chlorella vulgaris, Neochloris oleoabundans and Tetraselmis suecica) was studied in a lab scale bead mill at different bead sizes (0.3–1 mm). Cell disintegration, proteins and carbohydrates released into the water phase followed a first order

  17. Ni(2+)-zeolite/ferrosphere and Ni(2+)-silica/ferrosphere beads for magnetic affinity separation of histidine-tagged proteins.

    Science.gov (United States)

    Vereshchagina, T A; Fedorchak, M A; Sharonova, O M; Fomenko, E V; Shishkina, N N; Zhizhaev, A M; Kudryavtsev, A N; Frank, L A; Anshits, A G

    2016-01-28

    Magnetic Ni(2+)-zeolite/ferrosphere and Ni(2+)-silica/ferrosphere beads (Ni-ferrosphere beads - NFB) of a core-shell structure were synthesized starting from coal fly ash ferrospheres having diameters in the range of 0.063-0.050 mm. The strategy of NFB fabrication is an oriented chemical modification of the outer surface preserving the magnetic core of parent beads with the formation of micro-mesoporous coverings. Two routes of ferrosphere modification were realized, such as (i) hydrothermal treatment in an alkaline medium resulting in a NaP zeolite layer and (ii) synthesis of micro-mesoporous silica on the glass surface using conventional methods. Immobilization of Ni(2+) ions in the siliceous porous shell of the magnetic beads was carried out via (i) the ion exchange of Na(+) for Ni(2+) in the zeolite layer or (ii) deposition of NiO clusters in the zeolite and silica pores. The final NFB were tested for affinity in magnetic separation of the histidine-tagged green fluorescent protein (GFP) directly from a cell lysate. Results pointed to the high affinity of the magnetic beads towards the protein in the presence of 10 mM EDTA. The sorption capacity of the ferrosphere-based Ni-beads with respect to GFP was in the range 1.5-5.7 mg cm(-3).

  18. DWPF GLASS BEADS AND GLASS FRIT TRANSPORT DEMONSTRATION

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, D; Bradley Pickenheim, B

    2008-11-24

    DWPF is considering replacing irregularly shaped glass frit with spherical glass beads in the Slurry Mix Evaporator (SME) process to decrease the yield stress of the melter feed (a non-Newtonian Bingham Plastic). Pilot-scale testing was conducted on spherical glass beads and glass frit to determine how well the glass beads would transfer when compared to the glass frit. Process Engineering Development designed and constructed the test apparatus to aid in the understanding and impacts that spherical glass beads may have on the existing DWPF Frit Transfer System. Testing was conducted to determine if the lines would plug with the glass beads and the glass frit slurry and what is required to unplug the lines. The flow loop consisted of vertical and horizontal runs of clear PVC piping, similar in geometry to the existing system. Two different batches of glass slurry were tested: a batch of 50 wt% spherical glass beads and a batch of 50 wt% glass frit in process water. No chemicals such as formic acid was used in slurry, only water and glass formers. The glass beads used for this testing were commercially available borosilicate glass of mesh size -100+200. The glass frit was Frit 418 obtained from DWPF and is nominally -45+200 mesh. The spherical glass beads did not have a negative impact on the frit transfer system. The transferring of the spherical glass beads was much easier than the glass frit. It was difficult to create a plug with glass bead slurry in the pilot transfer system. When a small plug occurred from setting overnight with the spherical glass beads, the plug was easy to displace using only the pump. In the case of creating a man made plug in a vertical line, by filling the line with spherical glass beads and allowing the slurry to settle for days, the plug was easy to remove by using flush water. The glass frit proved to be much more difficult to transfer when compared to the spherical glass beads. The glass frit impacted the transfer system to the point

  19. DWPF GLASS BEADS AND GLASS FRIT TRANSPORT DEMONSTRATION

    International Nuclear Information System (INIS)

    Adamson, D.; Pickenheim, Bradley

    2008-01-01

    DWPF is considering replacing irregularly shaped glass frit with spherical glass beads in the Slurry Mix Evaporator (SME) process to decrease the yield stress of the melter feed (a non-Newtonian Bingham Plastic). Pilot-scale testing was conducted on spherical glass beads and glass frit to determine how well the glass beads would transfer when compared to the glass frit. Process Engineering Development designed and constructed the test apparatus to aid in the understanding and impacts that spherical glass beads may have on the existing DWPF Frit Transfer System. Testing was conducted to determine if the lines would plug with the glass beads and the glass frit slurry and what is required to unplug the lines. The flow loop consisted of vertical and horizontal runs of clear PVC piping, similar in geometry to the existing system. Two different batches of glass slurry were tested: a batch of 50 wt% spherical glass beads and a batch of 50 wt% glass frit in process water. No chemicals such as formic acid was used in slurry, only water and glass formers. The glass beads used for this testing were commercially available borosilicate glass of mesh size -100+200. The glass frit was Frit 418 obtained from DWPF and is nominally -45+200 mesh. The spherical glass beads did not have a negative impact on the frit transfer system. The transferring of the spherical glass beads was much easier than the glass frit. It was difficult to create a plug with glass bead slurry in the pilot transfer system. When a small plug occurred from setting overnight with the spherical glass beads, the plug was easy to displace using only the pump. In the case of creating a man made plug in a vertical line, by filling the line with spherical glass beads and allowing the slurry to settle for days, the plug was easy to remove by using flush water. The glass frit proved to be much more difficult to transfer when compared to the spherical glass beads. The glass frit impacted the transfer system to the point

  20. Extraction of uranium by hydroxybenzamide type polymers

    International Nuclear Information System (INIS)

    Sakuragi, Masako; Ichimura, Kunihiro; Suda, Yoshio; Marumo, Tomofuyu; Iwaki, Takao; Abe, Yoshimoto; Misono, Takahisa.

    1985-01-01

    Polyethyleneimine crosslinked with N,N'-methylenebisacrylamide was treated with substituted phenyl hydroxybenzoates to give the polymers having corresponding hydroxybenzamide groups. In these polymers I-V, polymer having 2-hydroxybenzamide group (I) and that having 2,4-dihydroxybenzamide group (II) showed the adsorption abilities of 45 and 87 μg-U/g in 4 days in seawater, respectively. The polymers having 2-hydroxybenzamide group in concentration from 1 to 20 mol % were prepared and the adsorption property for uranium was examined. Three mol % is most suitable concentration for treatment for 2-4 days, while 20 mol % is suitable for treatment for 30 days. The polymer prepared from porous polyethyleneimine bead showed higher adsorption ability than usual ones. (J.P.N.)

  1. Direct modification of hydrogen/deuterium-terminated diamond particles with polymers to form reversed and strong cation exchange solid phase extraction sorbents.

    Science.gov (United States)

    Yang, Li; Jensen, David S; Vail, Michael A; Dadson, Andrew; Linford, Matthew R

    2010-12-03

    We describe direct polymer attachment to hydrogen and deuterium-terminated diamond (HTD and DTD) surfaces using a radical initiator (di-tert-amyl peroxide, DTAP), a reactive monomer (styrene) and a crosslinking agent (divinylbenzene, DVB) to create polystyrene encapsulated diamond. Chemisorbed polystyrene is sulfonated with sulfuric acid in acetic acid. Surface changes were followed by X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS) and diffuse reflectance Fourier transform infrared spectroscopy (DRIFT). Finally, both polystyrene-modified DTD and sulfonated styrene-modified DTD were used in solid phase extraction (SPE). Percent recovery and column capacity were investigated for both phenyl (polystyrene) and sulfonic acid treated polystyrene SPE columns. These diamond-based SPE supports are stable under basic conditions, which is not the case for silica-based SPE supports. Copyright © 2010. Published by Elsevier B.V.

  2. Biodegradable Polymers

    OpenAIRE

    Vroman, Isabelle; Tighzert, Lan

    2009-01-01

    Biodegradable materials are used in packaging, agriculture, medicine and other areas. In recent years there has been an increase in interest in biodegradable polymers. Two classes of biodegradable polymers can be distinguished: synthetic or natural polymers. There are polymers produced from feedstocks derived either from petroleum resources (non renewable resources) or from biological resources (renewable resources). In general natural polymers offer fewer advantages than synthetic polymers. ...

  3. Towards a programmable magnetic bead microarray in a microfluidic channel

    International Nuclear Information System (INIS)

    Smistrup, Kristian; Bruus, Henrik; Hansen, Mikkel F.

    2007-01-01

    A new hybrid magnetic bead separator that combines an external magnetic field with 175 μm thick current lines buried in the back side of a silicon wafer is presented. A microfluidic channel was etched into the front side of the wafer. The large cross-section of the current lines makes it possible to use larger currents and obtain forces of longer range than from thin current lines at a given power limit. Guiding of magnetic beads in the hybrid magnetic separator and the construction of a programmable microarray of magnetic beads in the microfluidic channel by hydrodynamic focusing is presented

  4. The hydrogen-deuterium exchange of macromolecules

    International Nuclear Information System (INIS)

    Duane, C.J.

    1982-06-01

    An infra red spectroscopic technique has been developed which allows the hydrogen-deuterium exchange between a polymer and absorbed heavy water to be monitored with the polymer in contact with liquid heavy water. This method extends the existing methods to the highest possible internal water concentration. The results of Moore on the hydrogen-deuterium exchange of poly(N-t-butylacrylamide) have been extended to the lower homologues of the series. The rate and extent of the exchange of these polymers is dependent upon the pH of the conditioning solution in which the polymer is exposed prior to the exchange study. The exchange is acid and base catalysed with the latter only apparent in the lower homologues. The features of the acid catalysed exchange have been tentatively explained in terms of the mobility of the hydrogen ion in the polymer matrix, whilst the restricted base exchange is attributed to the lack of hydration stabilisation of the intermediate ion complex of the base catalysed mechanism. The hydrogen-deuterium exchange properties of nylon, silk and cellulose have also been studied and these polymers show far less sensitivity to the pH of the conditioning treatment. The results are discussed. (author)

  5. A two-channel detection method for autofluorescence correction and efficient on-bead screening of one-bead one-compound combinatorial libraries using the COPAS fluorescence activated bead sorting system

    International Nuclear Information System (INIS)

    Hintersteiner, Martin; Auer, Manfred

    2013-01-01

    One-bead one-compound combinatorial library beads exhibit varying levels of autofluorescence after solid phase combinatorial synthesis. Very often this causes significant problems for automated on-bead screening using TentaGel beads and fluorescently labeled target proteins. Herein, we present a method to overcome this limitation when fluorescence activated bead sorting is used as the screening method. We have equipped the COPAS bead sorting instrument with a high-speed profiling unit and developed a spectral autofluorescence correction method. The correction method is based on a simple algebraic operation using the fluorescence data from two detection channels and is applied on-the-fly in order to reliably identify hit beads by COPAS bead sorting. Our method provides a practical tool for the fast and efficient isolation of hit beads from one-bead one-compound library screens using either fluorescently labeled target proteins or biotinylated target proteins. This method makes hit bead identification easier and more reliable. It reduces false positives and eliminates the need for time-consuming pre-sorting of library beads in order to remove autofluorescent beads. (technical note)

  6. Stress Relaxation in Entangled Polymer Melts

    DEFF Research Database (Denmark)

    Hou, Ji-Xuan; Svaneborg, Carsten; Everaers, Ralf

    2010-01-01

    We present an extensive set of simulation results for the stress relaxation in equilibrium and step-strained bead-spring polymer melts. The data allow us to explore the chain dynamics and the shear relaxation modulus, G(t), into the plateau regime for chains with Z=40 entanglements and into the t......We present an extensive set of simulation results for the stress relaxation in equilibrium and step-strained bead-spring polymer melts. The data allow us to explore the chain dynamics and the shear relaxation modulus, G(t), into the plateau regime for chains with Z=40 entanglements...... excellent agreement for the Likhtman-McLeish theory using the double reptation approximation for constraint release, if we remove the contribution of high-frequency modes to contour length fluctuations of the primitive chain....

  7. Planar Hall effect bridge sensors with NiFe/Cu/IrMn stack optimized for self-field magnetic bead detection

    DEFF Research Database (Denmark)

    Henriksen, Anders Dahl; Rizzi, Giovanni; Hansen, Mikkel Fougt

    2016-01-01

    . The exchange bias field was found to decay exponentially with tCu and inversely with tFM. The reduced exchange field for larger values of tFM and tCu resulted in higher sensitivities to both magnetic fields and magnetic beads. We argue that the maximum magnetic bead signal is limited by Joule heating......The stack composition in trilayer Planar Hall effect bridge sensors is investigated experimentally to identify the optimal stack for magnetic bead detection using the sensor self-field. The sensors were fabricated using exchange-biased stacks Ni80Fe20(tFM)/Cu(tCu)/Mn80Ir20(10 nm) with tFM = 10, 20......, and 30 nm, and 0 ≤ tCu ≤ 0.6 nm. The sensors were characterized by magnetic hysteresis measurements, by measurements of the sensor response vs. applied field, and by measurements of the sensor response to a suspension of magnetic beads magnetized by the sensor self-field due to the sensor bias current...

  8. The state of Gd3+ ions in sulfo-and sulfophenol-containing ion exchange polymers according to the EPR data

    Science.gov (United States)

    Vishnevskaya, G. P.; Frolova, E. N.; Konstantinov, V. N.; Fakhrutdinov, A. R.

    2007-12-01

    The KU-2 and KU-1 universal cationites were found to exhibit partly selective properties with respect to Gd3+ ions. As distinct from the transition group cations studied earlier, gadolinium ions formed centers with SO{3/-} functional groups even in sulfo resin matrices hydrated to the greatest extent, and the fraction of these complexes increased as free water was removed from ionite matrices. The EPR spectra of gadolinium aquacomplexes in hydrated polymers were similar to their spectra in aqueous solutions. The strong crystal field condition ( D[Figure not available: see fulltext.] hv) with the presence of axial and rhombic components was fulfilled for fixed complexes. The spectra corresponded to complexes of two types. The effective g-factors and λ = E/D parameters were calculated to describe the spectra of systems with spin S = 7/2 quantitatively. The correlation times of rotational motion of aquacomplexes in hydrated cationites were determined. These times were found to be longer (1.5 to 3 times) than in aqueous solutions. Dipole-dipole interactions between gadolinium ions were studied to estimate the local concentrations of sorbed ions in large-sized pores.

  9. Magnetic dye-affinity beads for human serum albumin purification.

    Science.gov (United States)

    Odabası, Mehmet

    2011-01-01

    Cibacron Blue F3GA was covalently attached onto magnetic poly(vinyl alcohol) (mPVAL) beads (100-150 μm in diameter) for human serum albumin (HSA) adsorption from human plasma. Despite low nonspecific adsorption of HSA on mPVAL beads, Cibacron Blue F3GA attachment significantly increased the HSA adsorption. The maximum HSA adsorption was observed at pH 5.0. Higher HSA adsorption was observed from human plasma. Desorption of HSA from mPVAL beads was achieved by medium containing 1.0 M KSCN at pH 8.0. To test the efficiency of albumin adsorption from human serum, before and after albumin adsorption was demonstrated with sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analyses. HSA molecules could be reversibly adsorbed and desorbed 10 times with the magnetic beads without noticeable loss in their HSA adsorption capacity.

  10. Prior art relevant to active beads patent application

    CSIR Research Space (South Africa)

    Moolman, S

    2002-06-01

    Full Text Available This paper entails patents related to active beads containing encapsulated ingredients, patents cited by International Search Report on previous application and US patents related to suspension of inclusions in beverages...

  11. Effect of CaCO₃/HCl pretreatment on the surface modification of chitin gel beads via graft copolymerization of 2-hydroxy ethyl methacrylate and 4-vinylpyridine.

    Science.gov (United States)

    Yalinca, Zulal; Mohammed, Dana Ali Kader; Hadi, Jihad M; Yilmaz, Elvan

    2016-01-01

    Although chitin, poly(N-acetylglucosamine), possesses considerable potential as a biomaterial, it has not been as thoroughly studied as its derivative chitosan. In this study, the potential of chitin gel beads has been evaluated for surface modification via vinyl polymer grafting. Grafting behavior of two well-established vinyl monomers, namely 2-hydroxyethylmethacrylate (HEMA) and 4-vinylpyridine (4-VP) were investigated using cerium (IV) ammonium nitrate as the redox initiator with the aim of obtaining chemically functionalized more hydrophilic chitin surfaces. The intractable nature of chitin, which is one of its primary drawbacks as a grafting substrate was overcome by applying a CaCO3 treatment during bead preparation. The maximum grafting percentage of poly(HEMA) onto chitin bead without CaCO3 treatment was found to be 65%, while the value for CaCO3 treated chitin beads was 515%. The maximum grafting yield of poly(4-VP) on to CaCO3 treated chitin powder was 380% at optimum conditions. The grafting system was extensively characterized before and after grafting by FT-IR, SEM, C-13 NMR and XRD analyses. Significant improvement on the swelling capacities of chitin based gel beads in aqueous acidic, basic and neutral media was obtained. An account of the pros and cons of the system has been presented. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Mesalazine-probiotics beads for acetic acid experimental colitis: formulation and characterization of a promising new therapeutic strategy for ulcerative colitis.

    Science.gov (United States)

    Vishwakarma, Neelam; Ganeshpurkar, Aditya; Pandey, Vikas; Dubey, Nazneen; Bansal, Divya

    2015-01-01

    Acetic acid ulcerative colitis (UC) is an experimental condition created due to intra-rectal administration of acetic acid which causes inflammation and ulceration in the lining of colon and rectum. In such condition, the colon cannot absorb liquid from the stools, resulting in larger volume of watery stools. Mesalazine is mainly used for the treatment of UC but suffers from the drawback of having poor bioavailability. UC is also characterized by alteration in colonic microflora. The present work was focused on delivering mesalazine along with probiotic, which would facilitate to refurbish customary growth of microflora. Mesalazine and probiotic were encapsulated in pectin beads with an aim to protect the drug from gastric environment and target to colonic region. Pectin beads were prepared, formulation process was optimized for polymer concentration, drug concentration, cross-linking agent concentration. Formulation was characterized for surface morphology, in vitro drug release studies, determination of viable cell count, in vivo ulcer protective studies and stability studies. Average particle diameter of beads was ∼1.44-1.72 mm. Drug entrapment efficiency was found to be optimal (78-79%). A sustained release of drug was observed for 5 h; nearly 60% of drug was released at the end of 10 h. Microbiological studies of probiotic showed best cell viability. In acetic acid induced UC model, Mesalazine-probiotic beads-treated group showed significant (p probiotic loaded beads may serve as a useful colon specific drug delivery system for treatment of colitis.

  13. Ion Exchange Formation via Sulfonated Bicomponent Nonwovens

    Science.gov (United States)

    Stoughton, Hannah L.

    For many years ion exchange resins were used to: remove heavy metals from water, recover materials from wastewater, and eliminate harmful gases from the air. While use of these resin beads dominates the ion exchange industry, the beads have limitations that should be considered when decisions are made to employ them. For instance, officials must balance the inherent zero sum surface area and porosity of the materials. This series of studies investigates the use of bicomponent nonwovens as a base substrate for producing high surface area ion exchange materials for the removal of heavy metal ions. Functionalized materials were produced in a two-step process: (1) PET/PE spunbond bicomponent fibers were fractured completely, producing the high surface area nonwoven to be used as the base ion exchange material, and (2) the conditions for functionalizing the PET fibers of the nonwoven webs were investigated where an epoxy containing monomer was grafted to the surface followed by sulfonation of the monomer. The functionalization reactions of the PET fibers were monitored based on: weight gain, FTIR, TOF-SIMS, and SEM. Ion exchange properties were evaluated using titration and copper ion removal capacity from test solutions. The relationship between web structure and removal efficiency of the metal ions was defined through a comparison of the bicomponent and homocomponent nonwovens for copper ion removal efficiency. The investigation revealed that utilizing the high surface area, fractured bicomponent nonwoven ion exchange materials with capacities comparable to commercially available ion exchange resins could be produced.

  14. Exchange transfusion

    Science.gov (United States)

    ... count in a newborn (neonatal polycythemia) Rh-induced hemolytic disease of the newborn Severe disturbances in body chemistry Severe newborn jaundice ... exchange transfusion was performed to treat. Alternative Names Hemolytic disease - exchange transfusion Patient ... Exchange transfusion - series References Costa ...

  15. Synthesis of tentacle-type magnetic beads as immobilized metal-chelate affinity support for cytochrome c adsorption.

    Science.gov (United States)

    Türkmen, Deniz; Yavuz, Handan; Denizli, Adil

    2006-03-30

    Magnetic poly(2-hydroxyethylmethacrylate) (mPHEMA) beads with an average diameter of 100-140 microm were produced by suspension polymerization in the presence of magnetite particles (i.e. Fe3O4). Specific surface area and average pore size of the magnetic beads was found to be 50 m2/g and 819 nm, respectively. Ester groups in the mPHEMA structure were converted to imine groups by reacting with poly(ethyleneimine) (PEI) in the presence of NaH. Amino (-NH2) content of PEI-attached mPHEMA beads was determined as 102 mg PEI/g. Then, Cu2+ ions were chelated on the magnetic beads in the range of 20-793 micromol Cu2+/g. Cytochrome c (cyt c) adsorption was performed on the metal chelating beads from aqueous solutions containing different amounts of cyt c at different pHs, Cu2+ loadings and temperatures. Cyt c adsorption on the mPHEMA/PEI beads was 4.6 mg/g. Cu2+ chelation increased the cyt c adsorption significantly (40.1 mg/g). Adsorption capacity increased with Cu2+ loading and then reached a saturation value. Cyt c adsorption decreased with increasing temperature. Cyt c molecules could be reversibly adsorbed and eluted ten times with the magnetic adsorbents without noticeable loss in their cyt c adsorption capacity. The applicability of two kinetic models including pseudo-first order and pseudo-second order model was estimated on the basis of comparative analysis of the corresponding rate parameters, equilibrium capacity and correlation coefficients. Results suggest that chemisorption processes could be the rate-limiting step in the adsorption process. In the last part of this article, cyt c adsorption experiments were performed in a magnetically stabilized fluidized bed (MSFB) system at optimum conditions determined from the batch experiments. The adsorption capacity decreased significantly from 46.8 to 15.4 mg/g polymer with the increase of the flow-rate from 0.5 to 4.0 ml/min. The resulting magnetic chelator beads possessed excellent long-term storage stability.

  16. Lightweight High Strength Concrete with Expanded Polystyrene Beads

    OpenAIRE

    Subhan, Tengku Fitriani L

    2006-01-01

    This paper is a literature study about lightweight high strength concrete by incorporating expanded polystyrene beads. Basically polystyrene is disposal material from packaging industry. However, after being processed in a special manner, polystyrene can be expanded and used as lightweight concrete making material. Therefore, the use of expanded polystyrene beads in concrete is not only beneficial for engineering studies but also provide solution for the environmental problem

  17. Plasma membrane isolation using immobilized concanavalin A magnetic beads.

    Science.gov (United States)

    Lee, Yu-Chen; Srajer Gajdosik, Martina; Josic, Djuro; Lin, Sue-Hwa

    2012-01-01

    Isolation of highly purified plasma membranes is the key step in constructing the plasma membrane proteome. Traditional plasma membrane isolation method takes advantage of the differential density of organelles. While differential centrifugation methods are sufficient to enrich for plasma membranes, the procedure is lengthy and results in low recovery of the membrane fraction. Importantly, there is significant contamination of the plasma membranes with other organelles. The traditional agarose affinity matrix is suitable for isolating proteins but has limitation in separating organelles due to the density of agarose. Immobilization of affinity ligands to magnetic beads allows separation of affinity matrix from organelles through magnets and could be developed for the isolation of organelles. We have developed a simple method for isolating plasma membranes using lectin concanavalin A (ConA) magnetic beads. ConA is immobilized onto magnetic beads by binding biotinylated ConA to streptavidin magnetic beads. The ConA magnetic beads are used to bind glycosylated proteins present in the membranes. The bound membranes are solubilized from the magnetic beads with a detergent containing the competing sugar alpha methyl mannoside. In this study, we describe the procedure of isolating rat liver plasma membranes using sucrose density gradient centrifugation as described by Neville. We then further purify the membrane fraction by using ConA magnetic beads. After this purification step, main liver plasma membrane proteins, especially the highly glycosylated ones and proteins containing transmembrane domains could be identified by LC-ESI-MS/MS. While not described here, the magnetic bead method can also be used to isolate plasma membranes from cell lysates. This membrane purification method should expedite the cataloging of plasma membrane proteome.

  18. Polymer electronics

    CERN Document Server

    Hsin-Fei, Meng

    2013-01-01

    Polymer semiconductor is the only semiconductor that can be processed in solution. Electronics made by these flexible materials have many advantages such as large-area solution process, low cost, and high performance. Researchers and companies are increasingly dedicating time and money in polymer electronics. This book focuses on the fundamental materials and device physics of polymer electronics. It describes polymer light-emitting diodes, polymer field-effect transistors, organic vertical transistors, polymer solar cells, and many applications based on polymer electronics. The book also disc

  19. Configurational Statistics of Magnetic Bead Detection with Magnetoresistive Sensors.

    Science.gov (United States)

    Henriksen, Anders Dahl; Ley, Mikkel Wennemoes Hvitfeld; Flyvbjerg, Henrik; Hansen, Mikkel Fougt

    2015-01-01

    Magnetic biosensors detect magnetic beads that, mediated by a target, have bound to a functionalized area. This area is often larger than the area of the sensor. Both the sign and magnitude of the average magnetic field experienced by the sensor from a magnetic bead depends on the location of the bead relative to the sensor. Consequently, the signal from multiple beads also depends on their locations. Thus, a given coverage of the functionalized area with magnetic beads does not result in a given detector response, except on the average, over many realizations of the same coverage. We present a systematic theoretical analysis of how this location-dependence affects the sensor response. The analysis is done for beads magnetized by a homogeneous in-plane magnetic field. We determine the expected value and standard deviation of the sensor response for a given coverage, as well as the accuracy and precision with which the coverage can be determined from a single sensor measurement. We show that statistical fluctuations between samples may reduce the sensitivity and dynamic range of a sensor significantly when the functionalized area is larger than the sensor area. Hence, the statistics of sampling is essential to sensor design. For illustration, we analyze three important published cases for which statistical fluctuations are dominant, significant, and insignificant, respectively.

  20. Solvent effects on the collapse dynamics of polymers

    Science.gov (United States)

    Chang, Rakwoo; Yethiraj, Arun

    2001-05-01

    The effect of solvent on the collapse dynamics of polymers is studied using computer simulation. Two cases are investigated, one where the solvent is incorporated through a pairwise additive attraction between the polymer beads and a random force on each polymer bead, and another where the solvent is incorporated in an explicit fashion as a second component. Brownian dynamics and molecular dynamics simulations are used in the former and latter model, respectively, with intermolecular interactions chosen so that the equilibrium size of the polymer is similar in both models at similar conditions. In the Brownian dynamics simulations, at short times local blobs of monomers are found separated by linear segments. With time the blobs grow in size and coalesce to form sausage like shapes. These sausages gradually become thicker and shorter until the final shape of a spherical globule is reached. The first stage is rapid whereas the second sausage-sphere stage is slow. In this stage the polymer often gets trapped in local minima and the change in size with time occurs through discrete jumps, and the equilibrium conformation is often not reached. In contrast, in the molecular dynamics simulations with explicit solvent, the size of the polymer changes smoothly with time, and the polymer does not get trapped in local minima for the cases investigated, although the sequence of polymer shapes is similar. This suggests that incorporating solvent molecules explicitly is important in the computer simulations of collapse and folding of polymers.

  1. Polymer escape from a confining potential

    International Nuclear Information System (INIS)

    Mökkönen, Harri; Ikonen, Timo; Jónsson, Hannes; Ala-Nissila, Tapio

    2014-01-01

    The rate of escape of polymers from a two-dimensionally confining potential well has been evaluated using self-avoiding as well as ideal chain representations of varying length, up to 80 beads. Long timescale Langevin trajectories were calculated using the path integral hyperdynamics method to evaluate the escape rate. A minimum is found in the rate for self-avoiding polymers of intermediate length while the escape rate decreases monotonically with polymer length for ideal polymers. The increase in the rate for long, self-avoiding polymers is ascribed to crowding in the potential well which reduces the free energy escape barrier. An effective potential curve obtained using the centroid as an independent variable was evaluated by thermodynamic averaging and Kramers rate theory then applied to estimate the escape rate. While the qualitative features are well reproduced by this approach, it significantly overestimates the rate, especially for the longer polymers. The reason for this is illustrated by constructing a two-dimensional effective energy surface using the radius of gyration as well as the centroid as controlled variables. This shows that the description of a transition state dividing surface using only the centroid fails to confine the system to the region corresponding to the free energy barrier and this problem becomes more pronounced the longer the polymer is. A proper definition of a transition state for polymer escape needs to take into account the shape as well as the location of the polymer

  2. Biological Effects of Drug-Free Alginate Beads Cross-Linked by Copper Ions Prepared Using External Ionotropic Gelation.

    Science.gov (United States)

    Pavelková, M; Kubová, K; Vysloužil, J; Kejdušová, M; Vetchý, D; Celer, V; Molinková, D; Lobová, D; Pechová, A; Vysloužil, J; Kulich, P

    2017-05-01

    External ionotropic gelation offers a unique possibility to entrap multivalent ions in a polymer structure. The aim of this experimental study was to prepare new drug-free sodium alginate (ALG) particles cross-linked by Cu 2+ ions and to investigate their technological parameters (particle size, sphericity, surface topology, swelling capacity, copper content, release of Cu 2+ ions, mucoadhesivity) and biological activity (cytotoxicity and efficiency against the most common vaginal pathogens-Herpes simplex, Escherichia coli, Candida albicans) with respect to potential vaginal administration. Beads prepared from NaALG dispersions (3 or 4%) were cross-linked by Cu 2+ ions (0.5 or 1.0 M CuCl 2 ) using external ionotropic gelation. Prepared mucoadhesive beads with particle size over 1000 μm exhibited sufficient sphericity (all ˃0.89) and copper content (214.8-249.07 g/kg), which increased with concentration of polymer and hardening solution. Dissolution behaviour was characterized by extended burst effect, followed by 2 h of copper release. The efficiency of all samples against the most common vaginal pathogens was observed at cytotoxic Cu 2+ concentrations. Anti-HSV activity was demonstrated at a Cu 2+ concentration of 546 mg/L. Antibacterial activity of beads (expressed as minimum inhibition concentration, MIC) was influenced mainly by the rate of Cu 2+ release which was controlled by the extent of swelling capacity. Lower MIC values were found for E. coli in comparison with C. albicans. Sample ALG-3_1.0 exhibited the fastest copper release and was proved to be the most effective against both bacteria. This could be a result of its lower polymer concentration in combination with smaller particle size and thus larger surface area.

  3. Resin bead-thermal ionization mass spectrometry for determination of plutonium concentration in irradiated fuel dissolver solution

    International Nuclear Information System (INIS)

    Paul, Sumana; Shah, R.V.; Aggarwal, S.K.; Pandey, A.K.

    2015-01-01

    Determination of isotopic composition (IC) and concentration of plutonium (Pu) is necessary at various stages of nuclear fuel cycle which involves analysis of complex matrices like dissolver solution of irradiated fuel, nuclear waste stream etc. Mass spectrometry, e.g. thermal ionization mass spectrometry (TIMS) and inductively coupled plasma mass spectrometry (ICP-MS) are commonly used for determination of IC and concentration of plutonium. However, to circumvent matrix interferences, efficient separation as well as preconcentration of Pu is required prior to mass spectrometric analysis. Purification steps employing ion-exchange resins are widely used for the separation of Pu from dissolver solution or from mixture of other actinides e.g. U, Am. However, an alternative way is to selectively preconcentrate Pu on a resin bead, followed by direct loading of the bead on the filament of thermal ionization mass spectrometer

  4. From particle condensation to polymer aggregation

    Science.gov (United States)

    Janke, Wolfhard; Zierenberg, Johannes

    2018-01-01

    We draw an analogy between droplet formation in dilute particle and polymer systems. Our arguments are based on finite-size scaling results from studies of a two-dimensional lattice gas to three-dimensional bead-spring polymers. To set the results in perspective, we compare with in part rigorous theoretical scaling laws for canonical condensation in a supersaturated gas at fixed temperature, and derive corresponding scaling predictions for an undercooled gas at fixed density. The latter allows one to efficiently employ parallel multicanonical simulations and to reach previously not accessible scaling regimes. While the asymptotic scaling can not be observed for the comparably small polymer system sizes, they demonstrate an intermediate scaling regime also observable for particle condensation. Altogether, our extensive results from computer simulations provide clear evidence for the close analogy between particle condensation and polymer aggregation in dilute systems.

  5. Barter exchanges

    DEFF Research Database (Denmark)

    Sudzina, Frantisek

    Although barter is often perceived as something that proceeded money, barter is still used. The focus of the paper is on barter exchanges. Barter exchanges are used both in developing countries as well as in developed countries (including the U.S.). They are used by both organizations...... and individuals. They usually allow to exchange good but some include also services. Some exchanges allow only for bi-directional barter, i.e. when only two parties are involved in the exchange. But probably most of the barter exchanges use barter money; this makes it easier to exchange goods and services...

  6. Use of antibiotic beads to salvage infected breast implants.

    Science.gov (United States)

    Sherif, Rami D; Ingargiola, Michael; Sanati-Mehrizy, Paymon; Torina, Philip J; Harmaty, Marco A

    2017-10-01

    When an implant becomes infected, implant salvage is often performed where the implant is removed, capsulectomy is performed, and a new implant is inserted. The patient is discharged with a PICC line and 6-8 weeks of intravenous (IV) antibiotics. This method has variable success and subjects the patient to long-term systemic antibiotics. In the 1960s, the use of antibiotic-impregnated beads for the treatment of chronic osteomyelitis was described. These beads deliver antibiotic directly to the site of the infection, thereby eliminating the complications of systemic IV antibiotics. This study aimed to present a case series illustrating the use of STIMULAN calcium sulfate beads loaded with vancomycin and tobramycin to increase the rate of salvage of the infected implant and forgo IV antibiotics. A retrospective analysis was performed of patients who were treated at Mount Sinai Hospital for implant infection with salvage and antibiotic beads. Twelve patients were identified, 10 of whom had breast cancer. Comorbidities included hypertension, smoking, and immunocompromised status. Infections were noted anywhere from 5 days to 8 years postoperatively. Salvage was successful in 9 out of the 12 infected implants using antibiotic bead therapy without home IV antibiotics. The use of antibiotic beads is promising for salvaging infected breast implants without IV antibiotics. Seventy-five percent of the implants were successfully salvaged. Of the three patients who had unsalvageable implants, one was infected with antibiotic-resistant Rhodococcus that was refractory to bead therapy and one was noncompliant with postoperative instructions. Copyright © 2017 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  7. A polymer lab-on-a-chip for magnetic immunoassay with on-chip sampling and detection capabilities.

    Science.gov (United States)

    Do, Jaephil; Ahn, Chong H

    2008-04-01

    This paper presents a new polymer lab-on-a-chip for magnetic bead-based immunoassay with fully on-chip sampling and detection capabilities, which provides a smart platform of magnetic immunoassay-based lab-on-a-chip for point-of-care testing (POCT) toward biochemical hazardous agent detection, food inspection or clinical diagnostics. In this new approach, the polymer lab-on-a-chip for magnetic bead-based immunoassay consists of a magnetic bead-based separator, an interdigitated array (IDA) micro electrode, and a microfluidic system, which are fully incorporated into a lab-on-a-chip on cyclic olefin copolymer (COC). Since the polymer lab-on-a-chip was realized using low cost, high throughput polymer microfabrication techniques such as micro injection molding and hot embossing method, a disposable polymer lab-on-a-chip for the magnetic bead-based immunoassay can be successfully realized in a disposable platform. With this newly developed polymer lab-on-a-chip, an enzyme-labelled electrochemical immunoassay (ECIA) was performed using magnetic beads as the mobile solid support, and the final enzyme product produced from the ECIA was measured using chronoamperometry. A sampling and detection of as low as 16.4 ng mL(-1) of mouse IgG has been successfully performed in 35 min for the entire procedure.

  8. Confocal nanoscanning, bead picking (CONA): PickoScreen microscopes for automated and quantitative screening of one-bead one-compound libraries.

    Science.gov (United States)

    Hintersteiner, Martin; Buehler, Christof; Uhl, Volker; Schmied, Mario; Müller, Jürgen; Kottig, Karsten; Auer, Manfred

    2009-01-01

    Solid phase combinatorial chemistry provides fast and cost-effective access to large bead based libraries with compound numbers easily exceeding tens of thousands of compounds. Incubating one-bead one-compound library beads with fluorescently labeled target proteins and identifying and isolating the beads which contain a bound target protein, potentially represents one of the most powerful generic primary high throughput screening formats. On-bead screening (OBS) based on this detection principle can be carried out with limited automation. Often hit bead detection, i.e. recognizing beads with a fluorescently labeled protein bound to the compound on the bead, relies on eye-inspection under a wide-field microscope. Using low resolution detection techniques, the identification of hit beads and their ranking is limited by a low fluorescence signal intensity and varying levels of the library beads' autofluorescence. To exploit the full potential of an OBS process, reliable methods for both automated quantitative detection of hit beads and their subsequent isolation are needed. In a joint collaborative effort with Evotec Technologies (now Perkin-Elmer Cellular Technologies Germany GmbH), we have built two confocal bead scanner and picker platforms PS02 and a high-speed variant PS04 dedicated to automated high resolution OBS. The PS0X instruments combine fully automated confocal large area scanning of a bead monolayer at the bottom of standard MTP plates with semiautomated isolation of individual hit beads via hydraulic-driven picker capillaries. The quantification of fluorescence intensities with high spatial resolution in the equatorial plane of each bead allows for a reliable discrimination between entirely bright autofluorescent beads and real hit beads which exhibit an increased fluorescence signal at the outer few micrometers of the bead. The achieved screening speed of up to 200,000 bead assayed in less than 7 h and the picking time of approximately 1 bead

  9. Processes Leading to Beaded Channels Formation in Central Yakutia

    Science.gov (United States)

    Tarbeeva, A. M.; Lebedeva, L.; Efremov, V. S.; Krylenko, I. V.; Surkov, V. V.

    2017-12-01

    Beaded channels, consisting of deepened and widened pools and connecting narrow runs, are common fluvial forms in permafrost regions. Recent studies have shown that beaded channels are very important for connecting alluvial rivers with headwater lakes allowing fish passage and foraging habitats, as well as regulating river runoff. Beaded channels are known as typical thermokarst landforms; however, there is no evidence of their origin and formative processes. Geomorphological analyzes of beaded channels have been completed in several permafrost regions including field observations of Shestakovka River in Central Yakutia. The study aims to recognize the modern exogenic processes and formative mechanisms of beaded river channels. We show that beaded channel of Shestakovka River form in the perennially frozen sand with low ice content, leading us to hypothesize that thermokarst is not the main process of formation. Due to the significant volume of water, the pools don't freeze over entirely during winters, even under harsh climatic conditions. As a result, lenses of pressurized water remain under surface ice underlain by perennially thawed sediments. The presence of thawed sediments under the pools and frozen sediments under the runs leads to uneven thermoerosion of the riverbed during floods, providing the beaded form of the channel. In addition, freezing of pools during winter leads to pressure increasing under ice cover and formation of ice mounds, which crack several times during winter leading to disturbance of riverbanks. Many 1st to 3rd order streams have a specific transitional meandering-to-beaded form resembling the shape of unconfined meandering rivers, but consisting of pools and runs. However, such channels exhibit no evidences of present-day erosion of concave banks and sediment accumulation at the convex banks as typically being observed in normally meandering rivers. Such forms of channels indicates that their formation occurred by the greater channel

  10. Fluorescent detection of C-reactive protein using polyamide beads

    Science.gov (United States)

    Jagadeesh, Shreesha; Chen, Lu; Aitchison, Stewart

    2016-03-01

    Bacterial infection causes Sepsis which is one of the leading cause of mortality in hospitals. This infection can be quantified from blood plasma using C - reactive protein (CRP). A quick diagnosis at the patient's location through Point-of- Care (POC) testing could give doctors the confidence to prescribe antibiotics. In this paper, the development and testing of a bead-based procedure for CRP quantification is described. The size of the beads enable them to be trapped in wells without the need for magnetic methods of immobilization. Large (1.5 mm diameter) Polyamide nylon beads were used as the substrate for capturing CRP from pure analyte samples. The beads captured CRP either directly through adsorption or indirectly by having specific capture antibodies on their surface. Both methods used fluorescent imaging techniques to quantify the protein. The amount of CRP needed to give a sufficient fluorescent signal through direct capture method was found suitable for identifying bacterial causes of infection. Similarly, viral infections could be quantified by the more sensitive indirect capture method. This bead-based assay can be potentially integrated as a disposable cartridge in a POC device due to its passive nature and the small quantities needed.

  11. Bead resuspension and saltation in a turbulent channel flow

    Science.gov (United States)

    van Hout, Rene

    2013-11-01

    Resuspension and saltation of near neutrally buoyant, polystyrene beads in a turbulent boundary layer was studied using TR-PIV and PTV in a horizontal, water channel facility (Re = 7353). Near wall coherent structures were visualized using spatial distributions of vorticity and swirling strength in combination with instantaneous u1u2 correlations and u1. Two case studies, (i) on resuspension and (ii) on saltation showed that lift-off coincided with vortex core passage creating an ejection-sweep cycle. In all cases, beads left the wall when immersed in near-wall ejections and exposed to positive shear. A high shear induced lift force coincided with bead lift-off while the Magnus force and translation induced lift were negligible. The wall-normal component of the drag force mostly opposed lift-off. The difference between resuspension and saltation was governed by the type of coherent structures the beads encountered when lifted out of the viscous sublayer. Resuspension occurred when beads were carried upwards by a combination of a strong, spatially coherent upstream fast moving flow structure and a downstream ejection. On the other hand, saltation was accompanied by similar albeit weaker and spatially less coherent near-wall turbulence structures.

  12. Formation of RNA Beads from Various DNA Nanoring Structures.

    Science.gov (United States)

    Kim, Hyejin; Lee, Jong Bum

    2016-05-01

    By taking advantages of rolling circle transcription, one of the powerful methods to overcome the instability of RNA, we successfully synthesized RNA particles having high copy numbers of RNA strands. To examine dependence of RNA particle formation to template circular DNA strands, we synthesized RNA beads with 65-nt, 92-nt and 200-nt DNA nanoring structures as template circular DNA. Our conclusion is that characteristics of RNA beads could be controlled with various template circular DNA for RCT. It is feasible that our RNA beads could be used for RNAzyme-based metal sensors such as aqueous lead ion sensing. In this case, we expect that multi-metal ion detection would be possible by using 200-nt circular DNA bearing multiple desired functions as a template for RNA bead formation. Furthermore, certain features of RNA beads such as sensitivity to nuclease digestion and maximum loading amount of drugs when used as a carrier are expected to be further adjusted by choosing appropriate porosity and size.

  13. Tritium isotope separation by water distillation column packed with silica-gel beads

    International Nuclear Information System (INIS)

    Fukada, Satoshi

    2004-01-01

    Tritium enrichment or depletion by water distillation was investigated using a glass column of 32cm in height packed with silica-gel beads of 3.4mm in average diameter. The total separation factor of the silica-gel distillation column, α H-T , was compared with those of an open column distillation tower and of a column packed with stainless-steel Dixon rings. Depletion of the tritium activity in the distillate was enhanced by isotopic exchange with water absorbed on silica-gel beads that have a higher affinity for HTO than for H 2 O. The value of α H-T -1 of the silica-gel distillation column was about four times larger than that of a column without any packing and about two times larger than that of the Dixon-ring column. The improvement of α H-T by the silica-gel adsorbent indicated that the height of the distillation-adsorption column becomes shorter than that of the height of conventional distillation columns. (author)

  14. PHOTOREFRACTIVE POLYMERS

    NARCIS (Netherlands)

    Morichere, D; Malliaras, G.G; Krasnikov, V.V.; Bolink, H.J; Hadziioannou, G

    The use of polymers as photorefractive materials offers many advantages : flexibility in synthesis, doping, processing and low cost. The required functionalities responsible for photorefractivity, namely charge generation, transport, trapping and linear electrooptic effect are given in the polymer

  15. Polymer Nanocomposites

    Indian Academy of Sciences (India)

    polymer nanocompo- sites are used as advanced toner materials for high quality colour copiers and printers and as contrast agents in NMR analysis, memory devices. .... tions on polymer nanocomposite can thus pay rich dividends. Suggested Reading. [1] Metal-Polymer Nanocomposites Nicolais, Luigi(ed.) ; Carotenuto,.

  16. The dispersion of fine chitosan particles by beads-milling

    Science.gov (United States)

    Rochima, Emma; Utami, Safira; Hamdani, Herman; Azhary, Sundoro Yoga; Praseptiangga, Danar; Joni, I. Made; Panatarani, Camellia

    2018-02-01

    This research aimed to produce fine chitosan particles from a crab shell waste by beads-milling method by two different concentration of PEG as dispersing agent (150 and 300 wt. %). The characterization was performed to obtain the size and size distribution, the characteristics of functional groups and the degree of deacetylation. The results showed that the chitosan fine particles was obtained with a milling time 120 minutes with the best concentration of PEG 400 150 wt. %. The average particle size of the as-prepared suspension is 584 nm after addition of acetic acid solution (1%, v/v). Beads milling process did not change the glucosamine and N-acetylglucosamine content on chitosan structure which is indicated by degree of deacetylation higher than 70%. It was concluded that beads milling process can be applied to prepare chitosan fineparticles by proper adjustment in the milling time, pH and dosage of dispersing agent.

  17. Microinjected magnetic beads induce curvature in Chara rhizoids

    Science.gov (United States)

    Scherp, P.; Hasenstein, K.

    The gravitropic response of the Chara rhizoid is based on the interaction between the statoliths and the actin network located in the rhizoid apex. The rhizoid represents a model system for the study of gravitropism, because its apical cell contains the gravity sensing and response mechanism. In order to study the function of the statoliths and the cytoskeleton, we supplemented the naturally occurring statoliths with magnetic beads. These beads can be moved by an external magnetic field and they can be coated to interact with the cytoskeleton. The magnetic beads (1μm diameter) were injected close to the tip of the rhizoid in the presence of an external osmoticum to offset turgor pressure. The injection caused the formation of a noticeable plug of dense material at the site of impalement. After a recovery period of ca. 2 - 4 hours, the whole plant was mounted on the rotatable stage of a custom- built horizontal microscope, equipped with a long-working distance objective and a video camera. This stage is designed to reorientate the cell and/or the injected beads. In order to study the effect of the displacement of magnetic beads, an external magnetic field was applied. This external field was capable of displacing the magnetic particles but did not affect the natural statoliths. Work is in progress to quantify the response, to study the effect of microinjection on wall formation, and utilize coating of the beads to investigate their possible interaction with the original statoliths and with the microfilament network. Supported by NASA grant NAG 2- 1423.

  18. Beads of the Birsk Burial Ground in the Context of the Antiquities of the Early Middle Ages

    Directory of Open Access Journals (Sweden)

    Ruslanova Rida Raisovna

    2016-04-01

    Full Text Available Early Middle Ages in the Southern Urals is the time of the tumultuous ethnocultural processes, that is an echo of the era of the Great Migration. At this time, the bakhmutinskaya culture was formed (3rd-8th centuries A.D.. The Birsk burial ground is one of the unique monuments of this period – it appeared in the second third of the 1st millennium B.C. The Birsk burial ground is a fiducial monument for studying history, ethno-cultural, migration and trade processes occurring in the Southern Urals, and the content in the composition of grave goods makes it supplies an important source in the study of early medieval history of East European forest. A variety of types of beads from the Birsk burial ground allows suggesting that the necropolis was one of the major points on the caravan trade and exchange path. According to it, the exchange could take place on imports of products (furs, honey, metals. The article describes a set of beads from the Birsk burials – evidence of a monument in the system of early medieval antiquities (3rd-8th centuries A.D.. The complex morpho-technological research dealt with 218 complexes containing 6705 instances of beads and jewelry. The feature of the monument is the presence of necklaces jewelry from all the selected materials along with the material. The Birsk burial ground demonstrates various forms of products, colors used glass for monochrome and polychrome decorations. The presented work can be used in the study of material culture and trade exchange operations of the medieval population of the Urals.

  19. Corrosion of ancient glass beads found in Southern Thailand

    International Nuclear Information System (INIS)

    Won-in, K; Thongkam, Y; Intarasiri, S; Kamwanna, T; Dararutana, P

    2012-01-01

    Glass has been used as ornaments and decorations in Thailand for several hundred years. The archaeological resources suggested that the ancient glass beads excavated in southern Thailand were made more than 1300 years ago. Initial findings revealed that there were number of difference in shade between the glass beads of difference colors. Energy dispersive X-ray spectrometer (EDS) system attached with scanning electron microscope (SEM) and particle-induced X-ray emission spectroscopy (PIXE) were firstly used to study the surface corrosion of the samples. SEM micrographs showed more corroded and flaked microstructure. These were contributed to the interaction of both the ground water and its dissolved chemical compounds.

  20. Generalized Langevin Theory Of The Brownian Motion And The Dynamics Of Polymers In Solution

    International Nuclear Information System (INIS)

    Tothova, J.; Lisy, V.

    2015-01-01

    The review deals with a generalization of the Rouse and Zimm bead-spring models of the dynamics of flexible polymers in dilute solutions. As distinct from these popular theories, the memory in the polymer motion is taken into account. The memory naturally arises as a consequence of the fluid and bead inertia within the linearized Navier-Stokes hydrodynamics. We begin with a generalization of the classical theory of the Brownian motion, which forms the basis of any theory of the polymer dynamics. The random force driving the Brownian particles is not the white one as in the Langevin theory, but “colored”, i.e., statistically correlated in time, and the friction force on the particles depends on the history of their motion. An efficient method of solving the resulting generalized Langevin equations is presented and applied to the solution of the equations of motion of polymer beads. The memory effects lead to several peculiarities in the time correlation functions used to describe the dynamics of polymer chains. So, the mean square displacement of the polymer coils contains algebraic long-time tails and at short times it is ballistic. It is shown how these features reveal in the experimentally observable quantities, such as the dynamic structure factors of the scattering or the viscosity of polymer solutions. A phenomenological theory is also presented that describes the dependence of these quantities on the polymer concentration in solution. (author)

  1. Heat exchanger

    International Nuclear Information System (INIS)

    Dostatni, A.W.; Dostatni, Michel.

    1976-01-01

    In the main patent, a description was given of a heat exchanger with an exchange surface in preformed sheet metal designed for the high pressure and temperature service particularly encountered in nuclear pressurized water reactors and which is characterised by the fact that it is composed of at least one exchanger bundle sealed in a containment, the said bundle or bundles being composed of numerous juxtaposed individual compartments whose exchange faces are built of preformed sheet metal. The present addendun certificate concerns shapes of bundles and their positioning methods in the exchanger containment enabling its compactness to be increased [fr

  2. Evaluation of anti-inflammatory effect of silver-coated glass beads in mice with experimentally induced colitis as a new type of treatment in inflammatory bowel disease.

    Science.gov (United States)

    Siczek, Krzysztof; Zatorski, Hubert; Chmielowiec-Korzeniowska, Anna; Kordek, Radzisław; Tymczyna, Leszek; Fichna, Jakub

    2017-06-01

    Recent studies point at the anti-inflammatory action of silver through induction of apoptosis of inflammatory cells via oxidative stress, promotion of wound healing as well as antimicrobial effect. Our aim was to design a new formulation based on silver and validate its anti-inflammatory activity in the mouse models of colitis. Silver-coated glass beads were prepared using a magnetron sputtering method and a standard magnetron sputtering gun equipped with pure silver target. Colitis was induced by the ic administration of TNBS into colon (to mimic Crohn's disease) and addition of DSS to drinking water (to imitate ulcerative colitis). Evaluation of inflammation was performed based on macroscopic and microscopic scoring, quantification of the myeloperoxidase activity and colonic microflora analysis. Silver-coated glass beads administered ic alleviated intestinal inflammation in mouse models of colitis, induced by TNBS and DSS. This alleviation of colitis resulted principally from changes in the gut microflora. The anti-inflammatory action of the new formulation was associated predominantly with the presence of the silver nanolayer on the beads, and to a lesser extent the size of glass polymer units. The application of the newly developed formulation employing silver-coated glass beads has the potential to be translated to clinical conditions for the efficient treatment of IBD. Copyright © 2017 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

  3. Microstructural characteristics on bead on plate welding of AISI 904 ...

    African Journals Online (AJOL)

    In the present work, bead-on -plate welds were carried out on AISI 904 L super austenitic stainless steel sheets using Gas Metal Arc Welding (GMAW) process. In this present investigation AISI 904 L solid wire having 1.2 mm diameter was used as an electrode with direct current electrode positive polarity. Argon was ...

  4. Chitosan-Based Nanocomposite Beads for Drinking Water Production

    Science.gov (United States)

    Masheane, ML; Nthunya, LN; Sambaza, SS; Malinga, SP; Nxumalo, EN; Mamba, BB; Mhlanga, SD

    2017-05-01

    Potable drinking water is essential for the good health of humans and it is a critical feedstock in a variety of industries such as food and pharmaceutical industries. For the first time, chitosan-alumina/functionalised multiwalled carbon nanotube (f-MWCNT) nanocomposite beads were developed and investigated for the reduction of various physico-chemical parameters from water samples collected from open wells used for drinking purposes by a rural community in South Africa. The water samples were analysed before and after the reduction of the identified contaminants by the nanocomposite beads. The nanocomposite beads were effective in the removal of nitrate, chromium and other physico-chemical parameters. Although, the water samples contained these contaminants within the WHO and SANS241 limits for no risk, the long-term exposure and accumulation is an environmental and health concern. The reduction of these contaminants was dependent on pH levels. At lower pH, the reduction was significantly higher, up to 99.2% (SPC), 91.0% (DOC), 92.2% (DO), 92.2% (turbidity), 96.5% (nitrate) and 97.7% (chromium). Generally, the chitosan-alumina/f-MWCNT nanocomposite beads offer a promising alternative material for reduction and removal of various physico-chemical parameters for production portable water.

  5. Efficient functionalization of poly (styrene) beads immobilized metal ...

    Indian Academy of Sciences (India)

    Three types of new bead-shaped heterogeneous nanoparticle (NP) catalysts were synthesized by simplified procedures and studied for continuous reduction of crystal violet (CV) dye. The stabilizing agent, viz., 2-acryloxyethyltrimethyl ammonium chloride (PAC) was functionalized efficiently onto the surface of insoluble ...

  6. Continuous removal and recovery of lead by alginate beads, free ...

    African Journals Online (AJOL)

    This study examines the possibility of using Chlorella vulgaris cells in repeated lead adsorption/desorption cycles. Alginate beads and immobilized with algal cells were more effective and suitable than free cells. Consistently high lead removal (>90%) and recovery (about 100%) were achieved. Lead adsorption was mainly ...

  7. Superparamagnetic bead interactions with functionalized surfaces characterized by an immunomicroarray

    DEFF Research Database (Denmark)

    Skottrup, Peter Durand; Hansen, Mikkel Fougt; Moresco, Jacob Lange

    2010-01-01

    an immunomicroarray for systematic studies of the binding properties of 10 different micro-/nano-sized streptavidin-functionalized beads to a biotin substrate immobilized on SiO2 with or without surface modification SiO2 surface cleaning, immobilized substrate concentration and surface blocking conditions were...

  8. Bead-Based Microfluidic Sediment Analogues: Fabrication and Colloid Transport.

    Science.gov (United States)

    Guo, Yang; Huang, Jingwei; Xiao, Feng; Yin, Xiaolong; Chun, Jaehun; Um, Wooyong; Neeves, Keith B; Wu, Ning

    2016-09-13

    Mobile colloids can act as carriers for low-solubility contaminants in the environment. However, the dominant mechanism for this colloid-facilitated transport of chemicals is unclear. Therefore, we developed a bead-based microfluidic platform of sediment analogues and measured both single and population transport of model colloids. The porous medium is assembled through a bead-by-bead injection method. This approach has the versatility to build both electrostatically homogeneous and heterogeneous media at the pore scale. A T-junction at the exit also allowed for encapsulation and enumeration of colloids effluent at single particle resolution to give population dynamics. Tortuosity calculated from pore-scale trajectory analysis and its comparison with lattice Boltzmann simulations revealed that transport of colloids was influenced by the size exclusion effect. The porous media packed by positively and negatively charged beads into two layers showed distinctive colloidal particle retention and significant remobilization and re-adsorption of particles during water flushing. We demonstrated the potential of our method to fabricate porous media with surface heterogeneities at the pore scale. With both single and population dynamics measurement, our platform has the potential to connect pore-scale and macroscale colloid transport on a lab scale and to quantify the impact of grain surface heterogeneities that are natural in the subsurface environment.

  9. 485 assessment of the problems of manual automobile tyre bead ...

    African Journals Online (AJOL)

    eobe

    the sector, the diverse nature of its inputs and the unlimited value of its end products [1]. It generates employment for very many because of the numerous ..... reducing the energy and time expended on the bead breaking process. Some other respondents believe that the redesign engineer's attention should be focused on ...

  10. A new hybrid ion exchanger: Effect of system parameters on the adsorption of vanadium (V)

    Energy Technology Data Exchange (ETDEWEB)

    Yeom, Bong-Yeol [Nonwovens Cooperative Research Center, College of Textiles, North Carolina State University, Raleigh, NC 27695-8301 (United States); Lee, Chang-Soo [School of Applied Chemistry and Biological Engineering, College of Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Hwang, Taek-Sung, E-mail: tshwang@cnu.ac.kr [School of Applied Chemistry and Biological Engineering, College of Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of)

    2009-07-15

    The hybrid ion exchanger consisted of PONF-g-GMA anion fibrous exchanger and IRA-96 bead-type anion exchanger was developed by combining different types of layers with hot-melt adhesive. Its ion exchange capacity and the pressure drop with flow rate of water were measured and the adsorption of vanadium (V) ions on the hybrid ion exchanger was evaluated with various process parameters such as pH, initial concentration, and temperature. It was observed that the adsorption kinetics of vanadium (V) ions on the hybrid ion exchanger could be analyzed with pseudo-second-order model.

  11. Dynamical eigenmodes of star and tadpole polymers

    International Nuclear Information System (INIS)

    Keesman, Rick; Barkema, Gerard T; Panja, Debabrata

    2013-01-01

    The dynamics of phantom bead–spring chains with the topology of a symmetric star with f arms and tadpoles (f = 3, a special case) is studied, in the overdamped limit. In the simplified case where the hydrodynamic radius of the central monomer is f times as heavy as the other beads, we determine their dynamical eigenmodes exactly, along the lines of the Rouse modes for linear bead–spring chains. These eigenmodes allow full analytical calculations of virtually any dynamical quantity. As examples we determine the radius of gyration, the mean square displacement of a tagged monomer, and, for star polymers, the autocorrelation function of the vector that spans from the center of the star to a bead on one of the arms. (paper)

  12. Optimization and Evaluation of Magnetic Bead Separation Combined with Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectroscopy (MALDI-TOF MS for Proteins Profiling of Peritoneal Dialysis Effluent

    Directory of Open Access Journals (Sweden)

    Na Guo

    2014-01-01

    Full Text Available Peritoneal dialysis effluent (PDE potentially carries an archive of peptides relevant to pathological processes in abdominal and surrounding tissues. Magnetic beads and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry is one such approach that offers a unique tool for profiling of peptides, but this approach has not been used in the PDE analysis. In this study, we developed a strategy for screening PDE proteins <15 kDa and applied this technique to identify potential biomarkers for peritonitis. We examined four kinds of magnetic beads, including a carbon series (C3, C8, weak cation exchange (WCX and immobilized metal-affinity chromatography (IMAC-Cu beads. Samples processed with IMAC-Cu magnetic beads consistently showed more MS signals across all beads within the measured mass range. Moreover, there was no difference in the number and morphology of MS signals between concentrated and unconcentrated samples. The PDE peptidome pattern, based on a panel of 15 peaks, accurately recognized peritonitis PD patients from peritonitis-free patients with sensitivity of 90.5% and specificity of 94.7% respectively. Therefore, IMAC-Cu magnetic beads and unconcentrated samples can be used as a fast and cost-effective approach for sample preparation prior to more in-depth discovery of predictive biomarkers of disease in patients on dialysis.

  13. Single-stage mass spectrometric analyses of resin bead samples

    Energy Technology Data Exchange (ETDEWEB)

    Smith, D. H.; Walker, R. L.; Bertram, L. K.; Carter, J. A.

    1978-10-01

    Plutonium and uranium from dissolver solutions loaded on resin beads can be analyzed on single-stage mass spectrometers with little or no degradation of results provided proper care is exercised with regard to sample handling techniques. Additionally, storage of samples on resin beads is feasible for periods at least as long as six months provided the beads are not exposed to residual HNO/sub 3/ and air; it is probable that beads will retain their integrity much longer than six months when stored under collodion, but as yet no data to support this contention have been collected. Conventional or commercial mass spectrometers can readily be adapted to the resin bead technique by installing a pulse-counting detection system. The cost of such conversion will vary depending on whether or not a data acquisition system will be needed. A reasonable estimate is that the cost will be in the neighborhood of $15,000; this figure includes the price of a multi-channel analyzer to serve as a temporary data storage device, but does not include the cost of a computer. It does not appear that it will be practicable to switch easily back and forth between pulse-counting and current integration modes unless the instrument is provided with a movable Faraday cup. Using the same multiplier in both modes would undoubtedly degrade its performance in each. The requirements of low background counting rates and high gain for pulse counting, and of relatively high signal handling capacity in current integration are mutually incompatible if demanded of the same multiplier.

  14. Potential use of scrap expanded polystyrene beads for the control of Aedes triseriatus.

    Science.gov (United States)

    Beehler, J W; DeFoliart, G R

    1991-06-01

    The potential use of expanded polystyrene (EPS) beads for control of Aedes triseriatus was tested in the laboratory and the field. Laboratory studies showed that beads present in amounts which persisted throughout a season significantly reduced the emergence of Ae. triseriatus adults by preventing normal eclosion from the pupae. In the field, tree holes containing EPS beads had significantly fewer larvae present than untreated controls. These field data suggest that EPS beads may mechanically prevent oviposition by mosquitoes.

  15. Process and device for fabrication of ice beads and application to abrasive blasting with ice beads for surface treatments

    International Nuclear Information System (INIS)

    Barnier, M.; Manificat, A.; Perroud, P.

    1989-01-01

    A device is described for cleaning and decontamination by abrasive blasting with ice beads. It comprises a water injector, with many holes, at the top of a column feeded with cold gas where solidification of water droplets begins, solidification is completed in a cooling liquids, ice is extracted by a screw and pushed to the projection nozzle with cold gas [fr

  16. Polymer Chemistry

    Science.gov (United States)

    Williams, Martha; Roberson, Luke; Caraccio, Anne

    2010-01-01

    This viewgraph presentation describes new technologies in polymer and material chemistry that benefits NASA programs and missions. The topics include: 1) What are Polymers?; 2) History of Polymer Chemistry; 3) Composites/Materials Development at KSC; 4) Why Wiring; 5) Next Generation Wiring Materials; 6) Wire System Materials and Integration; 7) Self-Healing Wire Repair; 8) Smart Wiring Summary; 9) Fire and Polymers; 10) Aerogel Technology; 11) Aerogel Composites; 12) Aerogels for Oil Remediation; 13) KSC's Solution; 14) Chemochromic Hydrogen Sensors; 15) STS-130 and 131 Operations; 16) HyperPigment; 17) Antimicrobial Materials; 18) Conductive Inks Formulations for Multiple Applications; and 19) Testing and Processing Equipment.

  17. Star Polymers.

    Science.gov (United States)

    Ren, Jing M; McKenzie, Thomas G; Fu, Qiang; Wong, Edgar H H; Xu, Jiangtao; An, Zesheng; Shanmugam, Sivaprakash; Davis, Thomas P; Boyer, Cyrille; Qiao, Greg G

    2016-06-22

    Recent advances in controlled/living polymerization techniques and highly efficient coupling chemistries have enabled the facile synthesis of complex polymer architectures with controlled dimensions and functionality. As an example, star polymers consist of many linear polymers fused at a central point with a large number of chain end functionalities. Owing to this exclusive structure, star polymers exhibit some remarkable characteristics and properties unattainable by simple linear polymers. Hence, they constitute a unique class of technologically important nanomaterials that have been utilized or are currently under audition for many applications in life sciences and nanotechnologies. This article first provides a comprehensive summary of synthetic strategies towards star polymers, then reviews the latest developments in the synthesis and characterization methods of star macromolecules, and lastly outlines emerging applications and current commercial use of star-shaped polymers. The aim of this work is to promote star polymer research, generate new avenues of scientific investigation, and provide contemporary perspectives on chemical innovation that may expedite the commercialization of new star nanomaterials. We envision in the not-too-distant future star polymers will play an increasingly important role in materials science and nanotechnology in both academic and industrial settings.

  18. Polymer Electrolytes

    Science.gov (United States)

    Hallinan, Daniel T.; Balsara, Nitash P.

    2013-07-01

    This review article covers applications in which polymer electrolytes are used: lithium batteries, fuel cells, and water desalination. The ideas of electrochemical potential, salt activity, and ion transport are presented in the context of these applications. Potential is defined, and we show how a cell potential measurement can be used to ascertain salt activity. The transport parameters needed to fully specify a binary electrolyte (salt + solvent) are presented. We define five fundamentally different types of homogeneous electrolytes: type I (classical liquid electrolytes), type II (gel electrolytes), type III (dry polymer electrolytes), type IV (dry single-ion-conducting polymer electrolytes), and type V (solvated single-ion-conducting polymer electrolytes). Typical values of transport parameters are provided for all types of electrolytes. Comparison among the values provides insight into the transport mechanisms occurring in polymer electrolytes. It is desirable to decouple the mechanical properties of polymer electrolyte membranes from the ionic conductivity. One way to accomplish this is through the development of microphase-separated polymers, wherein one of the microphases conducts ions while the other enhances the mechanical rigidity of the heterogeneous polymer electrolyte. We cover all three types of conducting polymer electrolyte phases (types III, IV, and V). We present a simple framework that relates the transport parameters of heterogeneous electrolytes to homogeneous analogs. We conclude by discussing electrochemical stability of electrolytes and the effects of water contamination because of their relevance to applications such as lithium ion batteries.

  19. Chemical–physical characterisation of Early Iron Age glass beads from Central Europe

    Directory of Open Access Journals (Sweden)

    Fernando Agua

    2017-05-01

    Additionally, results showed microstructural and microcrystalline differences between some glass beads studied here and other glass beads from Mediterranean areas, dated in the same chronological period. This fact pointed out the valuable role given to these beads by Iron Age communities from Central Europe.

  20. Flow Cytometry-Based Bead-Binding Assay for Measuring Receptor Ligand Specificity

    NARCIS (Netherlands)

    Sprokholt, Joris K.; Hertoghs, Nina; Geijtenbeek, Teunis B. H.

    2016-01-01

    In this chapter we describe a fluorescent bead-binding assay, which is an efficient and feasible method to measure interaction between ligands and receptors on cells. In principle, any ligand can be coated on fluorescent beads either directly or via antibodies. Binding between ligand-coated beads

  1. Ionically crosslinked alginate–carboxymethyl cellulose beads for the delivery of protein therapeutics

    International Nuclear Information System (INIS)

    Kim, Min Sup; Park, Sang Jun; Gu, Bon Kang; Kim, Chun-Ho

    2012-01-01

    Highlights: ► We prepared Fe 3+ crosslinked alginate–carboxymethyl cellulose (AC) beads. ► Different surface and inner morphology of AC beads were observed on volume of CMC. ► AC beads showed minimum swelling degree in acidic condition. ► Protein release from AC beads was to control in gastrointestinal condition. - Abstract: We developed Fe 3+ -crosslinked alginate–carboxymethyl cellulose (AC) beads in various volume ratios by dropping an AC solution into a ferric chloride solution to form protein therapeutic carrier beads. Scanning electron microscopy revealed that the roughness and pore size of the crosslinked beads increased with the volume ratio of the carboxymethyl cellulose. Fourier transform-infrared analysis revealed the formation of a three-dimensional bonding structure between the anionic polymeric chains of AC and the Fe 3+ ions. The degree of swelling and the release profile of albumin from the beads were investigated under simulated gastrointestinal conditions (pH 1.2, 4.5, and 7.4). The Fe 3+ -crosslinked AC beads displayed different degrees of swelling and albumin release for the various AC volume ratios and under various pH conditions. An in vitro release test was used to monitor the controlled release of albumin from the AC beads under simulated gastrointestinal conditions over 24 h. The Fe 3+ -crosslinked AC beads protected and controlled the release of protein, demonstrating that such beads present a promising protein therapeutic carrier for the oral delivery.

  2. Prednisolone Delivery Platforms: Capsules and Beads Combination for a Right Timing Therapy.

    Directory of Open Access Journals (Sweden)

    Andrea Cerciello

    Full Text Available In this work, a platform of alginate beads loaded with Prednisolone in hypromellose/gellan gum capsules (F6/Cps able to delay steroidal anti-inflammatory drug (SAID release as needed for chronotherapy of rheumatoid arthritis is proposed. Rheumatoid arthritis, showing a worsening in symptoms in the morning upon waking, is a pathology that can benefit from chronotherapy. With the aim to maximize prednisolone therapeutic action allowing the right timing of glucocorticoid therapy, different engineered microparticles (gel-beads were manufactured using prilling (laminar jet break-up as micro-encapsulation technique and Zn-alginate as gastroresistant carrier. Starting from various feed solutions and process parameters, the effect of the variables on particles size, morphology, solid state properties and drug release was studied. The optimization of operative and prilling/ionotropic gelation variables led to microspheres with almost spherical shape and a narrow dimensional range. The feed solution with the highest alginate (2.5% w/v amount and drug/polymer ratio (1:5 w/w gave rise to the highest encapsulation efficiency (78.5% as in F6 formulation. As to drug release, F6 exhibited an interesting dissolution profile, releasing about 24% of the drug in simulated gastric fluid followed by a more sustained profile in simulated intestinal fluid. #F6, acting as a gastro-resistant and delayed release formulation, was selected for in vivo studies on male Wistar rats by means of a carrageenan-induced oedema model. Finally, this efficacious formulation was used as core material for the development of a final dosage form: F6/Cps allowed to significantly reduce prednisolone release in simulated gastric fluid (12.6% and delayed drug release up to about 390 minutes.

  3. Polymer chemistry (revised edition)

    International Nuclear Information System (INIS)

    Kim, Jae Mum

    1987-02-01

    This book deals with polymer chemistry, which is divided into fourteen chapters. The contents of this book are development of polymer chemistry, conception of polymer, measurement of polymer chemistry, conception of polymer, measurement of polymer, molecule structure of polymer, thermal prosperities of solid polymer, basic theory of polymerization, radical polymerization, ion polymerization, radical polymerization, copolymerization, polymerization by step-reaction, polymer reaction, crown polymer and inorganic polymer on classification and process of creation such as polymeric sulfur and carbon fiber.

  4. Synthesis and characterisation of alkaline anionic-exchange membranes for direct alcohol fuel cells

    CSIR Research Space (South Africa)

    Nonjola, P

    2007-12-01

    Full Text Available , but the most important being proton exchange membrane fuel cell (PEMFC), which uses an acidic membrane like Nafion (sulfonated fluorocarbon polymers) as an electrolyte. The use of polymer electrolytes represents an interesting path to pursue...

  5. Equilibrating high-molecular-weight symmetric and miscible polymer blends with hierarchical back-mapping

    Science.gov (United States)

    Ohkuma, Takahiro; Kremer, Kurt; Daoulas, Kostas

    2018-05-01

    Understanding properties of polymer alloys with computer simulations frequently requires equilibration of samples comprised of microscopically described long molecules. We present the extension of an efficient hierarchical backmapping strategy, initially developed for homopolymer melts, to equilibrate high-molecular-weight binary blends. These mixtures present significant interest for practical applications and fundamental polymer physics. In our approach, the blend is coarse-grained into models representing polymers as chains of soft blobs. Each blob stands for a subchain with N b microscopic monomers. A hierarchy of blob-based models with different resolution is obtained by varying N b. First the model with the largest N b is used to obtain an equilibrated blend. This configuration is sequentially fine-grained, reinserting at each step the degrees of freedom of the next in the hierarchy blob-based model. Once the blob-based description is sufficiently detailed, the microscopic monomers are reinserted. The hard excluded volume is recovered through a push-off procedure and the sample is re-equilibrated with molecular dynamics (MD), requiring relaxation on the order of the entanglement time. For the initial method development we focus on miscible blends described on microscopic level through a generic bead-spring model, which reproduces hard excluded volume, strong covalent bonds, and realistic liquid density. The blended homopolymers are symmetric with respect to molecular architecture and liquid structure. To parameterize the blob-based models and validate equilibration of backmapped samples, we obtain reference data from independent hybrid simulations combining MD and identity exchange Monte Carlo moves, taking advantage of the symmetry of the blends. The potential of the backmapping strategy is demonstrated by equilibrating blend samples with different degree of miscibility, containing 500 chains with 1000 monomers each. Equilibration is verified by comparing

  6. Processing method of radioactive spent ion exchange resin

    International Nuclear Information System (INIS)

    Shimizu, Takayuki; Saito, Tomohisa; Kurosaka, Norio.

    1997-01-01

    Resin beads and resin powders are collected from respective reservoir tanks to a supply tank, and the resin beads and the resin powders are continuously transferred from the supply tank to a dehydrator depending on the processing performance thereof to conduct dehydration. The obtained dehydrated resin beads and the powders are formed into a solidification product by cement solidification, or by incineration followed by cement solidification of incineration ashes, or are temporary stored in a storage vessel, and then subjected to one of the solidification treatments. It is possible to eliminate a worry of forming lumpy spent ion exchange resins in a storage tank to cause troubles upon withdrawal from the tank or during transportation. (N.H.)

  7. UV-induced polymerization of size-controlled platinum/poly[styrene-divinylbenzene-tri(propylene glycol diacrylate] hydrophobic catalyst beads in microfluidics

    Directory of Open Access Journals (Sweden)

    Jun Wei

    2015-10-01

    Full Text Available The catalytic exchange of hydrogen isotopes between hydrogen and water has been known to be a very useful process for the separation of tritium from tritiated water. For the process, a highly active hydrophobic catalyst is needed. This study provides an effective fabrication method of size-controlled platinum/poly[styrene-divinylbenzene-tri(propylene glycol diacrylate] [Pt/poly(SDB-TPGDA] hydrophobic catalyst beads with a narrow size distribution. Platinum nanoparticles were prepared by γ-ray-induced reduction in the aqueous phase first, and then uniformly dispersed in SDB-TPGDA comonomer after the hydrophobization of platinum nanoparticles with alkylamine stabilizers. The porous Pt/poly(SDB-TPGDA hydrophobic catalyst beads were synthesized by the UV-initiated polymerization of the mixture droplets prepared in a capillary-based microfluidic system. The size of as-prepared catalyst beads can be controlled in the range of 200–1,000 μm by adjusting the flow rate of dispersed and continuous phases, as well as the viscosity of the continuous phase. Sorbitan monooleate and cyclohexanol were used as coporogens to control the porosities of the catalyst beads.

  8. UV-induced polymerization of size-controlled platinum/poly[styrene-divinylbenzene-tri(propylene glycol) diacrylate] hydrophobic catalyst beads in microfluidics

    Energy Technology Data Exchange (ETDEWEB)

    Wi, Jun; Li, Xiang; Song, Tong; Song, Zi Fan; Chang, Zhen Qi [School of Nuclear Science and Technology, University of Science and Technology of China, Hefei (China); Meng, Da Qiao [Si Chuan Institute of Materials and Technology, Jiang You (China)

    2015-10-15

    The catalytic exchange of hydrogen isotopes between hydrogen and water has been known to be a very useful process for the separation of tritium from tritiated water. For the process, a highly active hydrophobic catalyst is needed. This study provides an effective fabrication method of size-controlled platinum/poly[styrene-divinylbenzene-tri(propylene glycol) diacrylate] [Pt/poly(SDB-TPGDA)] hydrophobic catalyst beads with a narrow size distribution. Platinum nanoparticles were prepared by γ-ray-induced reduction in the aqueous phase first, and then uniformly dispersed in SDB-TPGDA comonomer after the hydrophobization of platinum nanoparticles with alkylamine stabilizers. The porous Pt/poly(SDB-TPGDA) hydrophobic catalyst beads were synthesized by the UV-initiated polymerization of the mixture droplets prepared in a capillary-based microfluidic system. The size of as-prepared catalyst beads can be controlled in the range of 200-1,000 μm by adjusting the flow rate of dispersed and continuous phases, as well as the viscosity of the continuous phase. Sorbitan monooleate and cyclohexanol were used as coporogens to control the porosities of the catalyst beads.

  9. Polymer Nanocomposites

    Indian Academy of Sciences (India)

    thane, PVC, polyesters, polystyrene and polypropylene. Also, some biocompatible polymers like PLA, poly (E-caprolactone) to mention a few, have been synthesized by varying methods and with different clay loadings (%by weight). The hydrophobicity /hydrophilicity ofthe polymer affects its dispersion in the clay.

  10. On the chemical variability of Middelburg glass beads and rods

    International Nuclear Information System (INIS)

    Karklins, K.; Kottman, J.; Hancock, R.G.V.; Sempowski, M.L.; Nohe, A.W.; Moreau, J.-F.; Aufreiter, S.; Kenyon, I.

    2001-01-01

    Forty-three glass samples from a late 16th-early 17th century, glass beadmaking house in Middelburg, the Netherlands, were selected for maximum colouring variability, including plain and multi-coloured varieties. The glass chemistries were quite diverse, within each colour grouping. For each single colour of glass, anticipated colouring elements (copper for turquoise blue, cobalt for dark blue, manganese for rose, and tin for white) were used, with the exception of two beads that were opacified wih antimony rather than with tin. Multi-coloured glass glasses (chevron beads) produced chemistries that match the mixing of the different coloured glasses. In some cases, low relative amounts of some inter-mixed glasses were not detectable against the composition of the major glass component. (author). 16 refs., 3 tabs

  11. Random glycopeptide bead libraries for seromic biomarker discovery

    DEFF Research Database (Denmark)

    Kracun, Stjepan Kresimir; Cló, Emiliano; Clausen, Henrik

    2010-01-01

    glycopeptides were resynthesized at the preparative scale by automated parallel peptide synthesis and printed on microarrays for validation and broader analysis with larger sets of sera. We further showed that chemical synthesis of the monosaccharide O-glycopeptide library (Tn-glycoform) could be diversified...... have developed a random glycopeptide bead library screening platform for detection of autoantibodies and other binding proteins. Libraries were build on biocompatible PEGA beads including a safety-catch C-terminal amide linker (SCAL) that allowed mild cleavage conditions (I(2)/NaBH(4) and TFA......) for release of glycopeptides and sequence determination by ESI-Orbitrap-MS(n). As proof-of-principle, tumor -specific glycopeptide reporter epitopes were built-in into the libraries and were detected by tumor-specific monoclonal antibodies and autoantibodies from cancer patients. Sequenced and identified...

  12. Frictionless Demonstration Using Fine Plastic Beads For Teaching Mechanics

    International Nuclear Information System (INIS)

    Ishii, K.; Kagawa, K.; Khumaeni, A.; Kurniawan, K. H.

    2010-01-01

    New equipment for demonstrating laws of mechanics have successfully been constructed utilizing fine sphere plastic beads (0.3 mm in diameter). Fine plastic beads function as ball bearings to reduce the friction between the object and the plate surface. By this method, a quantitative measurement of energy conservation law has successfully been carried out with a small error of less 3%. The strong advantage of this frictionless method is that we can always use the same objects like Petri dishes for demonstrating many kinds of mechanics laws, such as the first, second, and the third laws of motion, momentum conservation law, and energy conservation law. This demonstration method surely has a beneficial effect for students, who can then understand mechanics laws systematically with a unified concept and no confusion.

  13. Separation of yttrium using carbon nanotube doped polymeric beads impregnated with D2EHPA

    International Nuclear Information System (INIS)

    Dasgupta, Kinshuk; Yadav, Kartikey K.; Singh, D.K.; Anitha, M.; Singh, H.

    2013-01-01

    Di-2-ethylhexyl phosphoric acid impregnated polyethersulfone based composite beads in combination with additives such as polyvinyl alcohol (PVA) and multiwalled carbon nanotube (MWCNT) has been prepared by non-solvent phase inversion method. The synthesized beads were characterized by scanning electron microscopy, thermogravimetry and infra-red spectroscopy. Effect of additives on bead morphology, solvent impregnation capacity, extractability and stability has been examined to compare their suitability for yttrium recovery from acidic medium. Microstructural investigation as well as experimental findings confirmed the role of additives in modifying the pore structures in beads, responsible for varied degree of yttrium extraction. Further the role of metal ion concentration in aqueous phase on its recovery by polymeric beads was also evaluated. Among the tested beads PES/D2EHPA/MWCNT/PVA beads were found to be superior for Y(Ill) extraction. (author)

  14. A planar conducting microstructure to guide and confine magnetic beads to a sensing zone

    KAUST Repository

    Gooneratne, Chinthaka Pasan

    2011-08-01

    A novel planar conducting microstructure is proposed to transport and confine magnetic micro/nano beads to a sensing zone. Manipulation and concentration of magnetic beads are achieved by employing square-shaped conducting micro-loops, with a few hundred nano-meters in thickness, arranged in a unique fashion. These microstructures are designed to produce high magnetic field gradients which are directly proportional to the force applied to manipulate the magnetic beads. Furthermore, the size of the microstructures allows greater maneuverability and control of magnetic beads than what could be achieved by permanent magnets. The aim of the microstructures is to guide magnetic beads from a large area and confine them to a smaller area where for example quantification would take place. Experiments were performed with different concentrations of 2 μm diameter magnetic beads. Experimental results showed that magnetic beads could be successfully guided and confined to the sensing zone. © 2011 Elsevier B.V. All rights reserved.

  15. Preventive maintenance technique by temper bead welding for reactor vessel

    International Nuclear Information System (INIS)

    Narita, Ryuichi; Kamo, Kazuhiko; Nishimura, Moritatsu; Nakamura, Yasuo; Hirano, Shinro

    2011-01-01

    Pressurized Water Reactor (PWR) plant has some dissimilar weld joint between main components which are made of Low Alloy Steel and piping which is made of Stainless Steel. Previous plants' dissimilar weld joints are made of Alloy 600 which is low resistance to Primary Water Stress Corrosion Cracking (PWSCC). It is reported that PWSCC is occurred in some plants. The preventive maintenance technique against PWSCC is needed immediately. One solution is the improvement of the material, for example, the inner surface of Alloy 600 is replaced by welding Alloy 690 which is high resistance to PWSCC. Generally, Heat Affected Zone (HAZ) of low alloy steel after welding is required Post Weld Heat Treatment (PWHT), but it is so hard that this operation has to be accomplished in site. So it is necessary to attempt the improvement of HAZ by temper bead welding which isn't needed PWHT. Temper bead welding is that HAZ of 1st weld layer is appropriately covered with heat of after 2nd weld layer, then the mechanical performance of HAZ is improved as well as PWHT. Conventional temper bead welding is required pre-heat and post-heat treatment. However it is impossible to set up the heater due to environment around the dissimilar weld joint in some plants, the development of ambient temperature temper bead welding technique which isn't needed pre-heat and post-heat treatment is expected. It is confirmed that the mechanical performance and the material texture are improved by setting the appropriate welding condition with many welding test pieces. Then, the preventive maintenances called INLAY method are completed in some actual plants. (author)

  16. Selective manipulation of superparamagnetic beads by a magnetic microchip

    KAUST Repository

    Gooneratne, Chinthaka Pasan

    2013-07-01

    In this paper, a magnetic microchip (MMC) is presented, to first trap and then selectively manipulate individual, superparamagnetic beads (SPBs) to another trapping site. Trapping sites are realized through soft magnetic micro disks made of Ni80Fe20, and SPB motion is controlled by current-carrying, tapered, conducting lines made of Au. The MMC was realized using standard microfabrication techniques and provides a cheap and versatile platform for microfluidic systems for cell manipulation. © 2013 IEEE.

  17. Hot wire TIG temper bead welding for nuclear repairs

    International Nuclear Information System (INIS)

    Lambert, J.A.; Gilston, P.F.

    1989-08-01

    A preliminary assessment has been carried out to determine the suitability of the hot wire tungsten inert gas (TIG) welding process for the repair of thick section, ferritic steel nuclear pressure vessels. The objective has been to identify a hot wire TIG temper bead procedure, suitable for repairs without post weld heat treatment. This procedure involves depositing two weld layers with carefully selected welding parameters such that overlapping thermal cycles produce a refined and tempered heat affected zone, HAZ, microstructure. (author)

  18. Structure and superparamagnetic behaviour of magnetite nanoparticles in cellulose beads

    Energy Technology Data Exchange (ETDEWEB)

    Correa, Jose R., E-mail: correa@fq.uh.cu [Department of General Chemistry, Faculty of Chemistry, University of Havana, Zapata and G, Havana City 10400 (Cuba); Bordallo, Eduardo [Sugar Cane-Cellulose Research Center, Cuba-9, Quivican (Cuba); Canetti, Dora [Department of Inorganic Chemistry, Faculty of Chemistry, University of Havana, Zapata and G, Havana City 10400 (Cuba); Leon, Vivian [Sugar Cane-Cellulose Research Center, Cuba-9, Quivican (Cuba); Otero-Diaz, Luis C. [Department of Inorganic Chemistry-1, Complutense University of Madrid, Madrid 28040 (Spain); Electron Microscopy Center, Complutense University of Madrid, Madrid 28040 (Spain); Negro, Carlos [Chemical Engineering Department, Complutense University of Madrid, Madrid 28040 (Spain); Gomez, Adrian [Electron Microscopy Center, Complutense University of Madrid, Madrid 28040 (Spain); Saez-Puche, Regino [Department of Inorganic Chemistry-1, Complutense University of Madrid, Madrid 28040 (Spain)

    2010-08-15

    Superparamagnetic magnetite nanoparticles were obtained starting from a mixture of iron(II) and iron(III) solutions in a preset total iron concentration from 0.04 to 0.8 mol l{sup -1} with ammonia at 25 and 70 {sup o}C. The regeneration of cellulose from viscose produces micrometrical spherical cellulose beads in which synthetic magnetite were embedded. The characterization of cellulose-magnetite beads by X-ray diffraction, Scanning and Transmission Electron Microscopy and magnetic measurement is reported. X-ray diffraction patterns indicate that the higher is the total iron concentration and temperature the higher is the crystal size of the magnetite obtained. Transmission Electron Microscopy studies of cellulose-magnetite beads revealed the distribution of magnetite nanoparticles inside pores of hundred nanometers. Magnetite as well as the cellulose-magnetite composites exhibit superparamagnetic characteristics. Field cooling and zero field cooling magnetic susceptibility measurements confirm the superparamagnetic behaviour and the blocking temperature for the magnetite with a mean size of 12.5 nm, which is 200 K.

  19. HOM identification by bead pulling in the Brookhaven ERL cavity

    CERN Document Server

    Hahn, H; Jain, Puneet; Johnson, Elliott C; Xu, Wencan

    2014-01-01

    Exploratory measurements of the Brookhaven Energy Recovery Linac (ERL) cavity at superconducting temperature produced a long list of high order modes (HOMs). The niobium 5-cell cavity is terminated at each end with HOM ferrite dampers that successfully reduce the Q-factors to levels required to avoid beam break up (BBU) instabilities. However, a number of un-damped resonances with Q≥106 were found at 4 K and their mode identification forms the focus of this paper. The approach taken here consists of bead pulling on a copper (Cu) replica of the ERL cavity with dampers involving various network analyzer measurements. Several different S21 transmission measurements are used, including those taken from the fundamental input coupler to the pick-up probe across the cavity, others between beam-position monitor probes in the beam tubes, and also between probes placed into the cells. The bead pull technique suitable for HOM identification with a metallic needle or dielectric bead is detailed. This paper presents the...

  20. Polymer supported sulphanilic acid: A highly efficient and recyclable ...

    Indian Academy of Sciences (India)

    tent were cooled and kept aside for one week with occa- sional shaking. At the end of reaction, the pH of reac- tion mixture came down from the 8 to 4. The yield of the modified thermosetting resin was 5.5 gm. Finally, the cross-linked polymer beads were filtered and washed with hot water followed by methanol and air dried.

  1. Heat exchanger

    International Nuclear Information System (INIS)

    Leigh, D.G.

    1976-01-01

    The arrangement described relates particularly to heat exchangers for use in fast reactor power plants, in which heat is extracted from the reactor core by primary liquid metal coolant and is then transferred to secondary liquid metal coolant by means of intermediate heat exchangers. One of the main requirements of such a system, if used in a pool type fast reactor, is that the pressure drop on the primary coolant side must be kept to a minimum consistent with the maintenance of a limited dynamic head in the pool vessel. The intermediate heat exchanger must also be compact enough to be accommodated in the reactor vessel, and the heat exchanger tubes must be available for inspection and the detection and plugging of leaks. If, however, the heat exchanger is located outside the reactor vessel, as in the case of a loop system reactor, a higher pressure drop on the primary coolant side is acceptable, and space restriction is less severe. An object of the arrangement described is to provide a method of heat exchange and a heat exchanger to meet these problems. A further object is to provide a method that ensures that excessive temperature variations are not imposed on welded tube joints by sudden changes in the primary coolant flow path. Full constructional details are given. (U.K.)

  2. Dynamic heat capacity of the east model and of a bead-spring polymer model.

    Energy Technology Data Exchange (ETDEWEB)

    McCoy, John Dwane (New Mexico Institute of Mining and Technology, Socorro, NM); Brown, Jonathan R. (New Mexico Institute of Mining and Technology, Socorro, NM); Adolf, Douglas Brian

    2011-10-01

    In this report we have presented a brief review of the glass transition and one means of characterizing glassy materials: linear and nonlinear thermodynamic oscillatory experiments to extract the dynamic heat capacity. We have applied these methods to the east model (a variation of the Ising model for glass forming systems) and a simple polymeric system via molecular dynamics simulation, and our results match what is seen in experiment. For the east model, since the dynamics are so simple, a mathematical model is developed that matches the simulated dynamics. For the polymeric system, since the system is a simulation, we can instantaneously 'quench' the system - removing all vibrational energy - to separate the vibrational dynamics from dynamics associated with particle rearrangements. This shows that the long-time glassy dynamics are due entirely to the particle rearrangements, i.e. basin jumping on the potential energy landscape. Finally, we present an extension of linear dynamic heat capacity to the nonlinear regime.

  3. “Nanofiltration” Enabled by Super-Absorbent Polymer Beads for Concentrating Microorganisms in Water Samples

    OpenAIRE

    Xie, Xing; Bahnemann, Janina; Wang, Siwen; Yang, Yang; Hoffmann, Michael R.

    2016-01-01

    Detection and quantification of pathogens in water is critical for the protection of human health and for drinking water safety and security. When the pathogen concentrations are low, large sample volumes (several liters) are needed to achieve reliable quantitative results. However, most microbial identification methods utilize relatively small sample volumes. As a consequence, a concentration step is often required to detect pathogens in natural waters. Herein, we introduce a novel water sam...

  4. Synthesis of zinc-crosslinked thiolated alginic acid beads and their in vitro evaluation as potential enteric delivery system with folic acid as model drug.

    Science.gov (United States)

    Taha, M O; Aiedeh, K M; Al-Hiari, Y; Al-Khatib, H

    2005-10-01

    The aim of this study is to explore the potential of synthetic modifications of alginic acid as a method to enhance the stability of its complexes with divalent cations under physiological conditions. A fraction of algin's carboxylic acid moieties was substituted with thiol groups to different substitution degrees through conjugating alginate to cysteine to produce alginate-cysteine (AC) conjugates. Infrared spectrophotometry and iodometry were used to characterize the resulting polymeric conjugates in terms of structure and degree of substitution. Moreover, zinc ions were used to crosslink the resulting AC polymers. Folic acid loaded beads were prepared from Zinc-crosslinked AC polymers (AC-Zn) of different cysteine substitution degrees. The generated beads were then investigated in vitro for their capacity to modify folic acid release. AC-Zn polymeric beads resisted drug release under acidic conditions (pH 1.0). However, upon transfer to a phosphate buffer solution (pH 7.0) they released most of their contents almost immediately. This change in drug release behavior is most probably due to the sequestering of zinc cations by phosphate ions within the buffer solution to form insoluble chelates and, to a lesser extent, the ionization of the carboxylic acid and thiol moieties. Removal of zinc ions from the polymeric matrix seems to promote polymeric disintegration and subsequent drug release. A similar behavior is expected in vivo due to the presence of natural zinc sequestering agents in the intestinal fluids. AC-Zn polymers provided a novel approach for enteric drug delivery as drug release from these matrices complied with the USP specifications for enteric dosage forms.

  5. Organometallic Polymers.

    Science.gov (United States)

    Carraher, Charles E., Jr.

    1981-01-01

    Reactions utilized to incorporate a metal-containing moiety into a polymer chain (addition, condensation, and coordination) are considered, emphasizing that these reactions also apply to smaller molecules. (JN)

  6. Determining the selectivity of divalent metal cations for the carboxyl group of alginate hydrogel beads during competitive sorption.

    Science.gov (United States)

    An, Byungryul; Lee, Healim; Lee, Soonjae; Lee, Sang-Hyup; Choi, Jae-Woo

    2015-11-15

    To investigate the competitive sorption of divalent metal ions such as Ca(2+), Cu(2+), Ni(2+), and Pb(2+) on alginate hydrogel beads, batch and column tests were conducted. The concentration of carboxyl group was found to be limited in the preparation of spherical hydrogel beads. From kinetic test results, 80% of sorption was observed within 4h, and equilibrium was attained in 48 h. According to the comparison of the total uptake and release, divalent metal ions were found to stoichiometrically interact with the carboxyl group in the alginate polymer chain. From the Langmuir equation, the maximum capacities of Pb(2+), Cu(2+), and Ni(2+) were calculated to be 1.1, 0.48, and 0.13 mmol/g, respectively. The separation factor (α) values for αPb/Cu, αPb/Ni, and αCu/Ni were 14.0, 98.9, and 7.1, respectively. The sorption capacity of Pb(2+) was not affected by the solution pH; however, the sorption capacities of Cu(2+) and Ni(2+) decreased with increasing solution pH, caused by competition with hydrogen. According to the result from the fixed column test, Pb(2+) exhibited the highest affinity, followed by Cu(2+) and Ni(2+), which is in exact agreement with those of kinetic and isotherm tests. The sorbent could be regenerated using 4% HCl, and the regenerated sorbent exhibited 90% capacity upto 9 cycles. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Characterization of the thickness and distribution of latex coatings on polyvinylidene chloride beads by backscattered electron imaging.

    Science.gov (United States)

    Todd, Clifford S; Beyer, Douglas E

    2015-04-01

    Polyvinylidene chloride (PVDC) co-polymer resins are commonly formulated with a variety of solid additives for the purpose of processing or stabilization. A homogeneous distribution of these additives during handling and processing is important. The Dow Chemical Company developed a process to incorporate solid materials in latex form onto PVDC resin bead surfaces using a coagulation process. In this context, we present a method to characterize the distribution and thickness of these latex coatings. The difference in backscattered electron signal from the higher mean atomic number PVDC core and lower atomic number latex coating in conjunction with scanning electron microscopy (SEM) imaging using a range of accelerating voltages was used to characterize latex thickness and distribution across large numbers of beads quickly and easily. Monte Carlo simulations were used to quantitatively estimate latex thickness as a function of brightness in backscatter electron images. This thickness calibration was validated by cross-sectioning using a focused ion-beam SEM. Thicknesses from 100 nm up to about 1.3 µm can be determined using this method.

  8. Free energy evaluation in polymer translocation via Jarzynski equality

    Energy Technology Data Exchange (ETDEWEB)

    Mondaini, Felipe, E-mail: fmondaini@if.ufrj.br [Centro Federal de Educação Tecnológica Celso Suckow da Fonseca, Petrópolis, 25.620-003, RJ (Brazil); Moriconi, L., E-mail: moriconi@if.ufrj.br [Instituto de Física, Universidade Federal do Rio de Janeiro, C.P. 68528, 21945-970, Rio de Janeiro, RJ (Brazil)

    2014-05-01

    We perform, with the help of cloud computing resources, extensive Langevin simulations, which provide free energy estimates for unbiased three-dimensional polymer translocation. We employ the Jarzynski equality in its rigorous setting, to compute the variation of the free energy in single monomer translocation events. In our three-dimensional Langevin simulations, the excluded-volume and van der Waals interactions between beads (monomers and membrane atoms) are modeled through a repulsive Lennard-Jones (LJ) potential and consecutive monomers are subject to the Finite-Extension Nonlinear Elastic (FENE) potential. Analysing data for polymers with different lengths, the free energy profile is noted to have interesting finite-size scaling properties.

  9. HEAT EXCHANGER

    Science.gov (United States)

    Fox, T.H. III; Richey, T. Jr.; Winders, G.R.

    1962-10-23

    A heat exchanger is designed for use in the transfer of heat between a radioactive fiuid and a non-radioactive fiuid. The exchanger employs a removable section containing the non-hazardous fluid extending into the section designed to contain the radioactive fluid. The removable section is provided with a construction to cancel out thermal stresses. The stationary section is pressurized to prevent leakage of the radioactive fiuid and to maintain a safe, desirable level for this fiuid. (AEC)

  10. Process to prepare stable trifluorostyrene containing compounds grafted to base polymers using a solvent/water mixture

    Science.gov (United States)

    Roelofs, Mark Gerrit; Yang, Zhen-Yu; Han, Amy Qi

    2010-06-15

    A fluorinated ion exchange polymer is prepared by grafting at least one grafting monomer derived from trifluorostyrene on to at least one base polymer in a organic solvent/water mixture. These ion exchange polymers are useful in preparing catalyst coated membranes and membrane electrode assemblies used in fuel cells.

  11. Modeling of weld bead geometry for rapid manufacturing by robotic GMAW

    Science.gov (United States)

    Yang, Tao; Xiong, Jun; Chen, Hui; Chen, Yong

    2015-03-01

    Weld-based rapid prototyping (RP) has shown great promises for fabricating 3D complex parts. During the layered deposition of forming metallic parts with robotic gas metal arc welding, the geometry of a single weld bead has an important influence on surface finish quality, layer thickness and dimensional accuracy of the deposited layer. In order to obtain accurate, predictable and controllable bead geometry, it is essential to understand the relationships between the process variables with the bead geometry (bead width, bead height and ratio of bead width to bead height). This paper highlights an experimental study carried out to develop mathematical models to predict deposited bead geometry through the quadratic general rotary unitized design. The adequacy and significance of the models were verified via the analysis of variance. Complicated cause-effect relationships between the process parameters and the bead geometry were revealed. Results show that the developed models can be applied to predict the desired bead geometry with great accuracy in layered deposition with accordance to the slicing process of RP.

  12. Polymers All Around You!

    Science.gov (United States)

    Gertz, Susan

    Background information on natural polymers, synthetic polymers, and the properties of polymers is presented as an introduction to this curriculum guide. Details are provided on the use of polymer products in consumer goods, polymer recycling, polymer densities, the making of a polymer such as GLUEP, polyvinyl alcohol, dissolving plastics, polymers…

  13. Heat exchanger

    International Nuclear Information System (INIS)

    Watabe, Ichiro.

    1996-01-01

    An inner cylinder is disposed coaxially in a vertical vessel, and a plurality of heat transfer pipes are wound spirally on the outer circumference of the inner cylinder. High temperature sodium descends on the outer side of the inner cylinder while exchanging heat with water in the heat transfer pipes and becomes low temperature sodium. The low temperature sodium turns at the lower portion of the vessel, rises in a sodium exit pipe inserted to the inner cylinder and is discharged from the top of the vessel to the outside of the vessel. A portion of a cover gas (an inert gas such as argon) filled to the upper portion of the vessel intrudes into the space between the outer circumference of the sodium exit pipe and the inner circumference of the inner cylinder to form a heat insulation layer of the inert gas. This prevents heat exchange between the high temperature sodium before heat exchange and low temperature sodium after heat exchange. The heat exchanger is used as a secondary heat exchanger for coolants (sodium) of an FBR type reactor. (I.N.)

  14. Predicting χ for polymers with stiffness mismatch from simulations

    Science.gov (United States)

    Kozuch, Daniel; Zhang, Wenlin; Gomez, Enrique; Milner, Scott

    The Flory-Huggins χ parameter describes the excess free energy of mixing and governs phase behavior for polymer blends and block copolymers. For chemically distinct polymers, the value of χ is dominated by the mismatch in cohesive energy densities of the monomers. For blends of chemically similar polymers, the entropic portion of χ, arising from non-ideal local packing, becomes more significant. Using polymer field theory, Fredrickson, Liu, and Bates predict that a difference in backbone stiffness can result in a positive χ for chains consisting of chemically identical monomers. To quantitatively investigate this phenomenon, we perform molecular dynamic (MD) simulations for bead-spring chains which differ only in stiffness. From the simulations, we apply a novel thermodynamic integration to extract χ as low as 10-3 per monomer for blends with mild stiffness mismatch. By introducing a standardized effective monomer, we map real polymers to our bead-spring chains and show that the predicted entropic portion of χ are consistent with experimental data.

  15. Biodegradation of ion-exchange media

    International Nuclear Information System (INIS)

    Bowerman, B.S.; Clinton, J.H.; Cowdery, S.R.

    1988-01-01

    The purpose of this study was to investigate further the potential for ion-exchange media (resin beads or powdered filter media) to support biological growth. A mixed microbial culture was grown from resin wastes obtained from the BNL HFBR by mixing the resin with a nutrient salt solution containing peptone and yeast extract. Bacterial and fungal growths appeared in the solution and on the resins after 7 to 10 days incubation at 337/degree/C. The mixed microbial cultures were used to inoculate several resin types, both irradiated and unirradiated. 12 refs., 5 tabs

  16. Polymers in nephrology. Characteristics and needs.

    Science.gov (United States)

    Vienken, J

    2002-05-01

    Polymers employed as biomaterials in nephrology serve for different applications: they form membranes for dialysis and plasmapheresis, are used as materials for dialyser housings and as a potting mass for capillary membranes, they make up tubing-systems for extracorporeal circuits and - in the form of beads - act as parts of adsorber columns for hemoperfusion or immunoadsorption. However, generally speaking, many polymers have not yet been designed for their final application. To date, many polymers are still taken from the chemist's shelf according to their alleged performance properties or to their sterilisability. When used in medical application, polymers must show a high purity. Uncontrolled leaching of oligomers from the polymer backbone or of additives from or during the manufacturing process must be avoided. Blood and other body fluids are extremely effective in extracting any loosely bound polymers. During long-term application, e.g. in patients suffering from chronic diseases, these effects may lead to an accumulation of these compounds in circulating blood, tissue, or joints. Consequently, polymers should show an excellent biostability and not degrade during their ageing process. The amount of extractable material should be kept low in order to avoid inflammatory reactions. Polymers must have high blood compatibility in terms of minimized cell- and complement activation. Polymers for medical application should at best be able to stand high temperatures in order to survive steam sterilisation. If this is impossible, their release kinetics for residual quantities of sterilizing agents should be fast. Finally, protein adsorption should appear under controlled conditions, otherwise a reduced performance through protein adsorption will take place. Further, the uncontrolled activation of biochemical cascades, such as the coagulation, complement or contact phase cascade, following blood/material contact must be minimized. A final aspect has been recently made

  17. Impact of Spherical Frit Beads on Simulated DWPF Slurries

    International Nuclear Information System (INIS)

    SMITH, MICHAEL

    2005-01-01

    It has been shown that the rheological properties of simulated Defense Waste Processing Facility (DWPF) melter feed with the glass former frit as mostly (90 weight percent) solid spherical particles (referred to as beads) were improved as the feed was less viscous as compared to DWPF melter feed that contained the normal irregular shaped frit particles. Because the physical design of the DWPF Slurry Mix Evaporator (SME), Melter Feed Tank (MFT), and melter feed loop are fixed, the impact of changing the rheology might be very beneficial. Most importantly, higher weight percent total solids feed might be processed by reducing the rheological properties (specifically yield stress) of the feed. Additionally, if there are processing problems, such as air entrainment or pumping, these problems might be alleviated by reducing the rheological properties, while maintaining targeted throughputs. Rheology modifiers are chemical, physical, or a combination of the two and can either thin or thicken the rheology of the targeted slurry. The beads are classified as a physical rheological modifier in this case. Even though the improved rheological properties of the feed in the above mentioned DWPF tanks could be quite beneficial, it is the possibility of increased melt rate that is the main driver for the use of beaded glass formers. By improving the rheological properties of the feed, the weight percent solids of the feed could be increased. This higher weight percent solids (less water) feed could be processed faster by the melter as less energy would be required to evaporate the water, and more would be available for the actual melting of the waste and the frit. In addition, the use of beads to thin the feed could possibly allow for the use of a lower targeted acid stoichiometry in the feed preparation process (if in fact acid stoichiometry is being driven by feed rheology as opposed to feed chemistry). Previous work by the Savannah River National Laboratory (SRNL) with the lab

  18. Poor Outcomes of Irrigation and Debridement in Acute Periprosthetic Joint Infection With Antibiotic-Impregnated Calcium Sulfate Beads.

    Science.gov (United States)

    Flierl, Michael A; Culp, Brian M; Okroj, Kamil T; Springer, Bryan D; Levine, Brett R; Della Valle, Craig J

    2017-08-01

    One proposed strategy to increase the success of irrigation and debridement with implant retention for the treatment of acute periprosthetic joint infection (PJI) is the use of dissolvable antibiotic-impregnated calcium sulfate beads to provide a local depot of antibiotics. The purpose of this study was to evaluate the outcome of such an approach. Thirty-two patients with acute hematogenous (18 patients; 1 bilateral) or acute postoperative (14 patients) PJIs who underwent irrigation and debridement with implant retention and addition of antibiotic-impregnated calcium sulfate beads were retrospectively reviewed. PJI followed 27 total knee arthroplasties and 6 total hip arthroplasties. The most common infecting organisms were methicillin-sensitive Staphylococcus aureus (13 of 33) and Streptococcus (9 of 33). The primary outcome parameter was recurrence of infection according to the Musculoskeletal Infection Society criteria. Patients were followed up for a minimum of 3 months or until failure. At a mean of 12.7 months (range, 3-30 months), 16 of the 33 patients failed (48%). Acute hematogenous and acute postoperative PJI had similar failure rates at 47% and 50%, respectively (P = .88). Seven failures required a 2-stage exchange, while 8 patients were treated with chronic antibiotic suppression, being unwilling or unable to undergo further surgical intervention. The addition of antibiotic-impregnated calcium sulfate beads does not appear to improve outcomes of irrigation and debridement with implant retention in the setting of acute hematogenous or acute postoperative PJI. Given the short follow-up in this report, this represents a best-case scenario and the overall failure rate may be higher with further follow-up. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Microscope-controlled glass bead blasting: a new technique

    Directory of Open Access Journals (Sweden)

    Peter Kotschy

    2011-01-01

    Full Text Available Peter Kotschy1, Sascha Virnik2, Doris Christ3, Alexander Gaggl21Private Practice, Vienna, Austria; 2Department of Oral and Maxillofacial Surgery, Central Hospital, Klagenfurt, Austria; 3Klagenfurt, AustriaObjective: The aim of periodontal therapy is the healing of periodontal inflammation; the protection of the attachment and the alveolar bone; and the regeneration of the periodontal structures. In the therapy of periodontitis, supra- and subgingival scaling and root planing plays a main role. The procedure described combines perfect root cleaning without scaling and root planing and minimal invasive periodontal surgery without a scalpel.Material and methods: Glass beads of 90 µm were used with the kinetic preparation unit PrepStart® under a pressure of 0.5–5 bar. This technique was practised only under visual control using the OPMI® PRO Magis microscope. Seven examinations were carried out at baseline after 3, 6, 12, 18, 24, and 36 months.Results: Time shows a statistically significant influence on all of the considered target variables (P < 0.0001 for all. As the according estimate is negative, probing depth decreases over time. The major decrease seems to be during the first 6 months. Considering probing depth, plaque on the main effect root shows significant influence (again, P < 0.0001 for all. Observations with high probing depth at the beginning were faster than those with low probing depth. The same characteristic appears by attachment level. Patients with more loss of attachment show more gain.Conclusions: Using microscope-controlled glass bead blasting results in a perfectly clean root surface using visual control (magnification 20×. Microscope-controlled glass bead blasting is therefore a good alternative to periodontal surgery.Keywords: periodontal therapy, microscope, periodontitis

  20. SparseBeads data: benchmarking sparsity-regularized computed tomography

    Science.gov (United States)

    Jørgensen, Jakob S.; Coban, Sophia B.; Lionheart, William R. B.; McDonald, Samuel A.; Withers, Philip J.

    2017-12-01

    Sparsity regularization (SR) such as total variation (TV) minimization allows accurate image reconstruction in x-ray computed tomography (CT) from fewer projections than analytical methods. Exactly how few projections suffice and how this number may depend on the image remain poorly understood. Compressive sensing connects the critical number of projections to the image sparsity, but does not cover CT, however empirical results suggest a similar connection. The present work establishes for real CT data a connection between gradient sparsity and the sufficient number of projections for accurate TV-regularized reconstruction. A collection of 48 x-ray CT datasets called SparseBeads was designed for benchmarking SR reconstruction algorithms. Beadpacks comprising glass beads of five different sizes as well as mixtures were scanned in a micro-CT scanner to provide structured datasets with variable image sparsity levels, number of projections and noise levels to allow the systematic assessment of parameters affecting performance of SR reconstruction algorithms6. Using the SparseBeads data, TV-regularized reconstruction quality was assessed as a function of numbers of projections and gradient sparsity. The critical number of projections for satisfactory TV-regularized reconstruction increased almost linearly with the gradient sparsity. This establishes a quantitative guideline from which one may predict how few projections to acquire based on expected sample sparsity level as an aid in planning of dose- or time-critical experiments. The results are expected to hold for samples of similar characteristics, i.e. consisting of few, distinct phases with relatively simple structure. Such cases are plentiful in porous media, composite materials, foams, as well as non-destructive testing and metrology. For samples of other characteristics the proposed methodology may be used to investigate similar relations.

  1. Blood Clotting Inspired Polymer Physics

    Science.gov (United States)

    Sing, Charles Edward

    The blood clotting process is one of the human body's masterpieces in targeted molecular manipulation, as it requires the activation of the clotting cascade at a specific place and a specific time. Recent research in the biological sciences have discovered that one of the protein molecules involved in the initial stages of the clotting response, von Willebrand Factor (vWF), exhibits counterintuitive and technologically useful properties that are driven in part by the physical environment in the bloodstream at the site of a wound. In this thesis, we take inspiration from initial observations of the vWF in experiments, and aim to describe the behaviors observed in this process within the context of polymer physics. By understanding these physical principles, we hope to harness nature's ability to both direct molecules in both spatial and conformational coordinates. This thesis is presented in three complementary sections. After an initial introduction describing the systems of interest, we first describe the behavior of collapsed Lennard-Jones polymers in the presence of an infinite medium. It has been shown that simple bead-spring homopolymer models describe vWF quite well in vitro. We build upon this previous work to first describe the behavior of a collapsed homopolymer in an elongational fluid flow. Through a nucleation-protrusion mechanism, scaling relationships can be developed to provide a clear picture of a first-order globule-stretch transition and its ramifications in dilute-solution rheology. The implications of this behavior and its relation to the current literature provides qualitative explanations for the physiological process of vasoconstriction. In an effort to generalize these observations, we present an entire theory on the behavior of polymer globules under influence of any local fluid flow. Finally, we investigate the internal dynamics of these globules by probing their pulling response in an analogous fashion to force spectroscopy. We elucidate

  2. Structurally stable gel bead containing entrapped enzyme and method for manufacture thereof

    Science.gov (United States)

    Woodward, J.

    1998-12-08

    This research provides a structurally stable gel bead containing an entrapped enzyme and a method for its manufacture. The enzyme is covalently cross-linked to gelatin in the presence of glutaraldehyde prior to the formation of the gel bead, to prevent leakage of the enzyme. Propylene glycol alginate is then added to the mixture. Once the gel beads are formed, they are then soaked in glutaraldehyde, which imparts structural stability to the gel beads. This method can be used with many types of enzymes, such as proteases, carbohydrases, proteases, ligases, isomerases, oxidoreductases, and specialty enzymes. These and other enzymes can be immobilized in the gel beads and utilized in a number of enzymatic processes. Exogenously added ions are not required to maintain the structural stability of these gel beads. 7 figs.

  3. Polymerase chain reaction system using magnetic beads for analyzing a sample that includes nucleic acid

    Science.gov (United States)

    Nasarabadi, Shanavaz [Livermore, CA

    2011-01-11

    A polymerase chain reaction system for analyzing a sample containing nucleic acid includes providing magnetic beads; providing a flow channel having a polymerase chain reaction chamber, a pre polymerase chain reaction magnet position adjacent the polymerase chain reaction chamber, and a post pre polymerase magnet position adjacent the polymerase chain reaction chamber. The nucleic acid is bound to the magnetic beads. The magnetic beads with the nucleic acid flow to the pre polymerase chain reaction magnet position in the flow channel. The magnetic beads and the nucleic acid are washed with ethanol. The nucleic acid in the polymerase chain reaction chamber is amplified. The magnetic beads and the nucleic acid are separated into a waste stream containing the magnetic beads and a post polymerase chain reaction mix containing the nucleic acid. The reaction mix containing the nucleic acid flows to an analysis unit in the channel for analysis.

  4. Intrinsic viscosity of bead models for macromolecules and bioparticles.

    Science.gov (United States)

    Gmachowski, L

    2001-10-01

    A new method based on the fractal dimension dependence of the hydrodynamic radius is proposed for calculation of the intrinsic viscosity of bead models. The method describes properly the viscosity increment except for elongated structures such as linear aggregates and ellipsoids. It is expected to be useful for very compact structures, for which the volume correction does not improve the results calculated by the modified Oseen tensor. The results obtained for the viscosity increment lie between the volume corrected ones and those determined by the cubic substitution procedure. They are close to the values recalculated from the falling velocities of the models analyzed.

  5. Radiation-induced synthesis of PAN and its amidoximation to produce beads for uranium extraction

    International Nuclear Information System (INIS)

    Singh, Krishan Kant; Shah, Chetan; Dwivedi, Charu; Kumar, Manmohan; Bajaj, P.N.

    2010-01-01

    Microporous polyacrylonitrile (PAN) beads, containing the amidoximated polyacrylonitrile sorbent, were synthesized for extraction of uranium. The kinetic measurement showed that about 120 minutes of equilibration time was enough to extract saturation amount of uranium from aqueous solution. The polymeric beads exhibited optimum extraction at 20 deg C and at neutral or near neutral pH conditions. The loaded uranium could also be leached out from the beads, by treating with dilute acids. (author)

  6. Ionically crosslinked alginate-carboxymethyl cellulose beads for the delivery of protein therapeutics

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Sup; Park, Sang Jun; Gu, Bon Kang [Laboratory of Tissue Engineering, Korea Institute of Radiological and Medical Science, Seoul 139-240 (Korea, Republic of); Kim, Chun-Ho, E-mail: chkim@kcch.re.kr [Laboratory of Tissue Engineering, Korea Institute of Radiological and Medical Science, Seoul 139-240 (Korea, Republic of)

    2012-12-01

    Highlights: Black-Right-Pointing-Pointer We prepared Fe{sup 3+} crosslinked alginate-carboxymethyl cellulose (AC) beads. Black-Right-Pointing-Pointer Different surface and inner morphology of AC beads were observed on volume of CMC. Black-Right-Pointing-Pointer AC beads showed minimum swelling degree in acidic condition. Black-Right-Pointing-Pointer Protein release from AC beads was to control in gastrointestinal condition. - Abstract: We developed Fe{sup 3+}-crosslinked alginate-carboxymethyl cellulose (AC) beads in various volume ratios by dropping an AC solution into a ferric chloride solution to form protein therapeutic carrier beads. Scanning electron microscopy revealed that the roughness and pore size of the crosslinked beads increased with the volume ratio of the carboxymethyl cellulose. Fourier transform-infrared analysis revealed the formation of a three-dimensional bonding structure between the anionic polymeric chains of AC and the Fe{sup 3+} ions. The degree of swelling and the release profile of albumin from the beads were investigated under simulated gastrointestinal conditions (pH 1.2, 4.5, and 7.4). The Fe{sup 3+}-crosslinked AC beads displayed different degrees of swelling and albumin release for the various AC volume ratios and under various pH conditions. An in vitro release test was used to monitor the controlled release of albumin from the AC beads under simulated gastrointestinal conditions over 24 h. The Fe{sup 3+}-crosslinked AC beads protected and controlled the release of protein, demonstrating that such beads present a promising protein therapeutic carrier for the oral delivery.

  7. IV injection of polystyrene beads for mouse model of sepsis causes severe glomerular injury.

    Science.gov (United States)

    Arima, Hajime; Hirate, Hiroyuki; Sugiura, Takeshi; Suzuki, Shugo; Takahashi, Satoru; Sobue, Kazuya

    2014-01-01

    Infusion fluids may be contaminated with different types of particulates that are a potential health hazard. Particulates larger than microvessels may cause an embolism by mechanical blockage and inflammation; however, it has been reported that particulates smaller than capillary diameter are relatively safe. Against such a background, one report showed that polystyrene beads smaller than capillary diameter decreased tissue perfusion in ischemia-reperfusion injury. This report suggested that polystyrene beads from 1.5- to 6-μm diameter (dia.) may have unfavorable effects after pretreatment. Here, we investigated whether injection of polystyrene beads (3- and 6-μm dia.) as an artificial contaminant of intravenous fluid after lipopolysaccharide (LPS) injection affected mortality and organ damage in mice. Mice were divided into four groups and injected: polystyrene beads only, LPS only, polystyrene beads 30 min after LPS, or saline. A survival study, histology, blood examination, and urine examination were performed. The survival rate after LPS and polystyrene bead (6-μm dia.) injection was significantly lower than that of the other three groups. In the kidney sections, injured glomeruli were significantly higher with LPS and polystyrene bead injection than that of the other three groups. LPS and polystyrene bead injection decreased the glomerular filtration rate and led to renal failure. Inflammatory reactions induced with LPS were not significantly different between with or without polystyrene beads. Polystyrene beads were found in urine after LPS and polystyrene bead injection. Injection of polystyrene beads after LPS injection enhanced glomerular structural injury and caused renal function injury in a mouse sepsis model.

  8. Hydrogen exchange

    DEFF Research Database (Denmark)

    Jensen, Pernille Foged; Rand, Kasper Dyrberg

    2016-01-01

    Hydrogen exchange (HX) monitored by mass spectrometry (MS) is a powerful analytical method for investigation of protein conformation and dynamics. HX-MS monitors isotopic exchange of hydrogen in protein backbone amides and thus serves as a sensitive method for probing protein conformation...... and dynamics along the entire protein backbone. This chapter describes the exchange of backbone amide hydrogen which is highly quenchable as it is strongly dependent on the pH and temperature. The HX rates of backbone amide hydrogen are sensitive and very useful probes of protein conformation......, as they are distributed along the polypeptide backbone and form the fundamental hydrogen-bonding networks of basic secondary structure. The effect of pressure on HX in unstructured polypeptides (poly-dl-lysine and oxidatively unfolded ribonuclease A) and native folded proteins (lysozyme and ribonuclease A) was evaluated...

  9. On-chip measurements of Brownian relaxation vs. concentration of 40nm magnetic beads

    DEFF Research Database (Denmark)

    Østerberg, Frederik Westergaard; Rizzi, Giovanni; Hansen, Mikkel Fougt

    2012-01-01

    We present on-chip Brownian relaxation measurements on a logarithmic dilution series of 40 nm beads dispersed in water with bead concentrations between 16 mu g/ml and 4000 mu g/ml. The measurements are performed using a planar Hall effect bridge sensor at frequencies up to 1 MHz. No external fields...... are needed as the beads are magnetized by the field generated by the applied sensor bias current. We show that the Brownian relaxation frequency can be extracted from fitting the Cole-Cole model to measurements for bead concentrations of 64 mu g/ml or higher and that the measured dynamic magnetic response...

  10. Glass bead cultivation of fungi - combining the best of liquid and agar media

    DEFF Research Database (Denmark)

    Droce, Aida; Sørensen, Jens Laurids; Giese, Henriette

    2013-01-01

    Production of bioactive compounds and enzymes from filamentous fungi is highly dependent on cultivation conditions. Here we present an easy way to cultivate filamentous fungi on glass beads which allow complete control of nutrient supply. Secondary metabolite production in Fusarium graminearum...... and Fusarium solani cultivated on agar plates, in shaking liquid culture or on glass beads was compared. Agar plate culture and glass bead cultivation yielded comparable results while liquid culture had lower production of secondary metabolites. RNA extraction from glass beads and liquid cultures was easier...

  11. Fluctuations of cytoskeleton-bound microbeads-the effect of bead-receptor binding dynamics

    International Nuclear Information System (INIS)

    Metzner, C; Raupach, C; Mierke, C T; Fabry, B

    2010-01-01

    The cytoskeleton (CSK) of living cells is a crosslinked fiber network, subject to ongoing biochemical remodeling processes that can be visualized by tracking the spontaneous motion of CSK-bound microbeads. The bead motion is characterized by anomalous diffusion with a power-law time evolution of the mean square displacement (MSD), and can be described as a stochastic transport process with apparent diffusivity D and power-law exponent β: MSD ∼ D (t/t 0 ) β . Here we studied whether D and β change with the time that has passed after the initial bead-cell contact, and whether they are sensitive to bead coating (fibronectin, integrin antibodies, poly-L-lysine, albumin) and bead size (0.5-4.5 μm). The measurements are interpreted in the framework of a simple model that describes the bead as an overdamped particle coupled to the fluctuating CSK network by an elastic spring. The viscous damping coefficient characterizes the degree of bead internalization into the cell, and the spring constant characterizes the strength of the binding of the bead to the CSK. The model predicts distinctive signatures of the MSD that change with time as the bead couples more tightly to the CSK and becomes internalized. Experimental data show that the transition from the unbound to the tightly bound state occurs in an all-or-nothing manner. The time point of this transition shows considerable variability between individual cells (2-30 min) and depends on the bead size and bead coating. On average, this transition occurs later for smaller beads and beads coated with ligands that trigger the formation of adhesion complexes (fibronectin, integrin antibodies). Once the bead is linked to the CSK, however, the ligand type and bead size have little effect on the MSD. On longer timescales of several hours after bead addition, smaller beads are internalized into the cell more readily, leading to characteristic changes in the MSD that are consistent with increased viscous damping by the

  12. Multi-modal particle manipulator to enhance bead-based bioassays

    Science.gov (United States)

    Glynne-Jones, P.; Boltryk, R. J.; Hill, M.; Zhang, F.; Dong, L.; Wilkinson, J. S.; Brown, T.; Melvin, T.; Harris, N. R.

    2010-01-01

    By sequentially pushing micro-beads towards and away from a sensing surface, we show that ultrasonic radiation forces can be used to enhance the interaction between a functionalized glass surface and polystyrene micro-beads, and distinguish those that bind to the surface, ultimately by using an integrated optical waveguide implanted in the reflector to facilitate optical detection. The movement towards and immobilization of streptavidin coated beads onto a biotin functionalized waveguide surface is achieved by using a quarter-wavelength mode pushing beads onto the surface, while the removal of non-specifically bound beads uses a second quarter-wavelength mode which exhibits a kinetic energy maxima at the boundary between the carrier layer and fluid, drawing beads towards this surface. This has been achieved using a multi-modal acoustic device which exhibits both these quarter-wavelength resonances. Both 1-D acoustic modeling and finite element analysis has been used to design this device and investigate the spatial uniformity of the field. We demonstrate experimentally that 90% of specifically bound beads remain attached after applying ultrasound, with 80% of non-specifically bound control beads being successfully removed acoustically. This approach overcomes problems associated with lengthy sedimentation processes used for bead-based bioassays and surface (electrostatic) forces, which delay or prevent immobilization. We explain the potential of this technique in the development of DNA and protein assays in terms of detection speed and multiplexing.

  13. On-chip magnetic bead-based DNA melting curve analysis using a magnetoresistive sensor

    DEFF Research Database (Denmark)

    Rizzi, Giovanni; Østerberg, Frederik Westergaard; Henriksen, Anders Dahl

    2014-01-01

    We present real-time measurements of DNA melting curves in a chip-based system that detects the amount of surface-bound magnetic beads using magnetoresistive magnetic field sensors. The sensors detect the difference between the amount of beads bound to the top and bottom sensor branches of the di......We present real-time measurements of DNA melting curves in a chip-based system that detects the amount of surface-bound magnetic beads using magnetoresistive magnetic field sensors. The sensors detect the difference between the amount of beads bound to the top and bottom sensor branches...

  14. Ormosil Beads for Insulation of Ground Cryogenic Storage Tanks, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Organically modified silica (Ormosil) aerogel beads developed at Aspen Aerogels, Inc. offer several advantages for retrofitting perlite insulation in NASA's ground...

  15. Orbeez: the magic water absorbing bead--risk of pediatric bowel obstruction?

    Science.gov (United States)

    Darracq, Michael A; Cullen, Jennifer; Rentmeester, Landen; Cantrell, F Lee; Ly, Binh T

    2015-06-01

    In December 2012, the U.S. Consumer Product Safety Commission recalled the water-absorbing toy WaterBalz after reports of small intestine obstruction after ingestion by children. Orbeez, another water-absorbing bead, remains available and is marketed as a children's toy. We sought to determine the extent to which Orbeez enlarge in various liquid media and the potential risk for bowel obstruction. Three Orbeez beads were added to 210 mL of the following liquid media: room temperature tap water, whole milk, simulated gastric fluid, GoLytely (polyethelyelene glycol, 3350 and electrolytes), and vodka (40% ethanol by volume). Diameters before exposure to media were measured using a caliper to the nearest 0.1 mm and again at 1, 2, 4, 6, 12, and 24 hours. Ten beads were then added to the beads already immersed in simulated gastric fluid and water and observed for an additional 72 hours (96 hours total) for clumping or increase in diameter. Clumping was defined as two or more beads remaining persistently adherent to one another despite gentle circular movement (swirling) of the liquid. Growth in each of the media was observed. Growth in simulated gastric fluid was minimal, whereas the beads were observed to be the largest after 24 hours in vodka. Clumping of the beads was not observed to occur. Orbeez beads enlarge to a different extent in different liquid media. It is unlikely that Orbeez beads would expand to sizes or demonstrate clumping that would be concerning for intestinal obstruction.

  16. Specific serum protein biomarkers of rheumatoid arthritis detected by MALDI-TOF-MS combined with magnetic beads.

    Science.gov (United States)

    Niu, Qian; Huang, Zhuochun; Shi, Yunying; Wang, Lanlan; Pan, Xiaofu; Hu, Chaojun

    2010-07-01

    To identify novel serum protein biomarkers and establish diagnostic pattern for rheumatoid arthritis (RA) by using proteomic technology. Serum proteomic spectra were generated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) combined with weak cationic exchange magnetic beads. A training set of spectra, derived from analyzing sera from 22 patients with RA, 26 patients with other autoimmune diseases and 25 age- and sex-matched healthy volunteers, was used to train and develop a decision tree model with a machine learning algorithm called decision boosting. A blinded testing set, including 21 patients with RA, 24 patients with other autoimmune diseases and 25 healthy people, was used to examine the accuracy of the model. A decision tree model was established, consisting of four potential protein biomarkers whose m/z values were 4966.88, 5065.3, 5636.97 and 7766.87, respectively. In validation test, the decision tree model could differentiate RA from other autoimmune diseases and healthy people with the sensitivity of 85.71% and specificity of 87.76%, respectively. The present data suggested that MALDI-TOF-MS combined with magnetic beads could screen and identify some novel serum protein biomarkers related to RA. The proteomic pattern based on the four candidate biomarkers is of value for laboratory diagnosis of RA.

  17. The Use of Heterogeneous Catalysts of Chitosan Sulfonate Bead on the Esterification Reaction of Oleic Acid and Methanol

    Science.gov (United States)

    Chamidy, H. N.; Riniati

    2017-05-01

    Biodiesel is one of the ester compounds with physical properties closer to a biodiesel which can be produced by the esterification reaction between methanol and oleic acid (one of major components present in Palm Fatty Acid Distillate, PFAD). The purpose of this study was to obtain an optimum condition of esterification reaction by using chitosan sulfonate bead as heterogeneous catalysts. Chitosan sulfonate bead was made from chitosan undergo sulfonation process using acidic reagents cross-linked with sulfosalicylic and glutaraldehyde with a high enough value of ion exchange capacity. The stage of esterification reactions was carried by varying the amount of catalyst being added (4, 6, 8, 10, 12% by oleic acid), the operating temperature was varied of 40, 50 and 60 °C, and the reaction time of 1, 2, 3, 4 and 5 hours. Conversion determination of the products was done by analysing the free fatty acids content in each sample. Having obtained from the optimum amount of catalyst being added, temperature, and time, it was found that the catalyst was at 8%, 50 °C, during 5 hours in operation. The maximum conversion of oleic acid into biodiesel was 73.12%.

  18. Antimocrobial Polymer

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, William F. (Utica, OH); Huang, Zhi-Heng (Walnut Creek, CA); Wright, Stacy C. (Columbus, GA)

    2005-09-06

    A polymeric composition having antimicrobial properties and a process for rendering the surface of a substrate antimicrobial are disclosed. The composition comprises a crosslinked chemical combination of (i) a polymer having amino group-containing side chains along a backbone forming the polymer, (ii) an antimicrobial agent selected from quaternary ammonium compounds, gentian violet compounds, substituted or unsubstituted phenols, biguanide compounds, iodine compounds, and mixtures thereof, and (iii) a crosslinking agent containing functional groups capable of reacting with the amino groups. In one embodiment, the polymer is a polyamide formed from a maleic anhydride or maleic acid ester monomer and alkylamines thereby producing a polyamide having amino substituted alkyl chains on one side of the polyamide backbone; the crosslinking agent is a phosphine having the general formula (A)3P wherein A is hydroxyalkyl; and the antimicrobial agent is chlorhexidine, dimethylchlorophenol, cetyl pyridinium chloride, gentian violet, triclosan, thymol, iodine, and mixtures thereof.

  19. Fabrication of Cationic Exchange Polystyrene Nanofibers for Drug ...

    African Journals Online (AJOL)

    Trop J Pharm Res, February 2014; 13(2): 192. Many polymers are used to produce nanofibers by electrospinning. Polystyrene (PS) is one of polymers used to produce cation exchange fibers. [9]. PS nanofibers were successfully produced using the electrospinning method and it has been demonstrated that electrospun PS.

  20. Imade-imide cross-linked PEEK proton exchange membrane.

    CSIR Research Space (South Africa)

    Luo, H

    2009-08-01

    Full Text Available The proton exchange membrane is a key component of polymer electrolyte membrane fuel cell (PEMFC). It plays an important role, conducts protons and separates the fuel from oxidant in PEMFC. DuPont’s Nafion is a perfluorinated sulfonic acid polymer...

  1. Polymer electronics

    CERN Document Server

    Geoghegan, Mark

    2013-01-01

    Polymer electronics is the science behind many important new developments in technology, such as the flexible electronic display (e-ink) and many new developments in transistor technology. Solar cells, light-emitting diodes, and transistors are all areas where plastic electronics is likely to, or is already having, a serious impact on our daily lives. With polymer transistors and light-emitting diodes now being commercialised, there is a clear need for a pedagogic text thatdiscusses the subject in a clear and concise fashion suitable for senior undergraduate and graduate students. The content

  2. Flow Cytometric Bead Sandwich Assay Based on a Split Aptamer.

    Science.gov (United States)

    Shen, Luyao; Bing, Tao; Liu, Xiangjun; Wang, Junyan; Wang, Linlin; Zhang, Nan; Shangguan, Dihua

    2018-01-24

    A few aptamers still bind their targets after being split into two moieties. Split aptamers have shown great potential in the development of aptameric sensors. However, only a few split aptamers have been generated because of lack of knowledge on the binding structure of their parent aptamers. Here, we report the design of a new split aptamer and a flow cytometric bead sandwich assay using a split aptamer instead of double antibodies. Through DMS footprinting and mutation assay, we figured out the target-binding moiety and the structure-stabilizing moiety of the l-selectin aptamer, Sgc-3b. By separating the duplex strand in the structure-stabilizing moiety, we obtained a split aptamer that bound l-selectin. After optimization of one part of the split sequence to eliminate the nonspecific binding of the split sequence pair, we developed a split-aptamer-based cytometric bead assay (SACBA) for the detection of soluble l-selectin. SACBA showed good sensitivity and selectivity to l-selectin and was successfully applied for the detection of spiked l-selectin in the human serum. The strategies for generating split aptamers and designing the split-aptamer-based sandwich assay are simple and efficient and show good practicability in aptamer engineering.

  3. Direct oligonucleotide synthesis onto super-paramagnetic beads

    Science.gov (United States)

    Jensen, Michael A; Akhras, Michael S.; Fukushima, Marilyn; Pourmand, Nader; Davis, Ron W.

    2013-01-01

    Super-paramagnetic beads (SPMB)s used for a variety of molecular diagnostic assays are prepared by attaching pre-synthesized oligonucleotides to the surface via a cumbersome and low efficient method of carbodiimide-mediated amide bond formation. To mainstream the process, we describe a novel procedure of direct oligonucleotide synthesis onto the surface of SPMBs (e.g. MyOne Dynabeads). With the many challenges surrounding containment of paramagnetic beads (≤ 1 μm) during automated oligonucleotide synthesis, we show that by applying a magnetic force directly to the SPMBs we prevent their loss caused by high-pressure drain steps during synthesis. To date we have synthesized 40mers using a Spacer 9 phosphoramidite (triethylene glycol) coupled to the surface of hydroxylated SPMBs. HPLC analysis shows successful product generation with an average yield of 200 pmoles per sample. Furthermore, because of the versatility of this powerful research tool, we envision its use in any laboratory working with conventional synthesis automation, as employed for single columns and for multi-well titer plates. In addition to direct synthesis of oligodeoxynucleotides (DNA) onto SPMBs, this platform also has the potential for RNA and peptide nucleic acid synthesis. PMID:23942380

  4. Envenomation by a wild Guatemalan Beaded Lizard Heloderma horridum charlesbogerti.

    Science.gov (United States)

    Ariano-Sánchez, Daniel

    2008-11-01

    The Guatemalan Beaded Lizard (Heloderma horridum charlesbogerti) is an endemic venomous lizard that inhabits southeastern Guatemala. Published reports of bites by Beaded Lizard are scarce. This is the first case report of a bite from Heloderma horridum charlesbogerti. A 24-year-old man was bitten on the left hand by a juvenile Heloderma horridum charlesbogerti. The lizard remained attached for approximately 15 seconds. The patient experienced severe local pain, dizziness, diaphoresis, vomiting, severe paresthesia in his left hand and arm, and hypotension (70/52 mm/Hg). He was treated with intravenous ketorolac, chlorpheniramine, methylprednisolone, antibiotics, ondansentron, and normal saline. Hematology tests revealed leukocytosis (12,600/mm3). Symptoms improved and the patient was discharged from hospital 24 hours after admission. The case reported here shows that bites by Heloderma produce severe clinical effects shortly after the bite. Management consists of waiting for the lizard to relax its bite pressure and using pliers to open lizard's mouth and pull out the bitten extremity, a careful manual search for teeth remnants, and supportive care. In our case, severe pain, unresponsive to non-steroidal anti-inflammatory analgesics, was a major problem. Parethesias resolve quickly but pain may persist for up to 12 hours after the bite. A full recovery is expected.

  5. Simulation of Enzyme Catalysis in Calcium Alginate Beads

    Directory of Open Access Journals (Sweden)

    Ameel M. R. Al-Mayah

    2012-01-01

    Full Text Available A general mathematical model for a fixed bed immobilized enzyme reactor was developed to simulate the process of diffusion and reaction inside the biocatalyst particle. The modeling and simulation of starch hydrolysis using immobilized α-amylase were used as a model for this study. Corn starch hydrolysis was carried out at a constant pH of 5.5 and temperature of . The substrate flow rate was ranging from 0.2 to 5.0 mL/min, substrate initial concentrations 1 to 100 g/L. α-amylase was immobilized on to calcium alginate hydrogel beads of 2 mm average diameter. In this work Michaelis-Menten kinetics have been considered. The effect of substrate flow rate (i.e., residence time and initial concentration on intraparticle diffusion have been taken into consideration. The performance of the system is found to be affected by the substrate flow rate and initial concentrations. The reaction is controlled by the reaction rate. The model equation was a nonlinear second order differential equation simulated based on the experimental data for steady state condition. The simulation was achieved numerically using FINITE ELEMENTS in MATLAB software package. The simulated results give satisfactory results for substrate and product concentration profiles within the biocatalyst bead.

  6. LAMINAR SETTLING OF GLASS BEADS IN VISCO-PLASTIC LIQUIDS

    Directory of Open Access Journals (Sweden)

    Mikoláš Kesely

    2016-04-01

    Full Text Available The paper deals with a determination of the terminal settling velocity of coarse particles in quiescent visco-plastic liquids of Herschel-Bulkley type. Experiments on laminar settling of glass beads of different sizes were conducted in transparent Carbopol solutions of various rheological properties in a sedimentation column. The terminal settling velocity of a solitude bead was determined together with the rheological parameters of the Carbopol liquid. An evaluation of the experimental results confirms the existence of the laminar regime for all tests and compares the measured velocities with predictions by Wilson et al. method. Furthermore, an alternative method is proposed for a prediction of the terminal settling velocity in the laminar regime which uses a particle-based determination of the strain rate in the expression for the equivalent viscosity. A comparison with our experimental results shows that the predictions using the proposed method agree well with the experiments and the proposed method is in the laminar settling regime more accurate than the Wilson et al. method.

  7. The bead on a rotating hoop revisited: an unexpected resonance

    Science.gov (United States)

    Raviola, Lisandro A.; Véliz, Maximiliano E.; Salomone, Horacio D.; Olivieri, Néstor A.; Rodríguez, Eduardo E.

    2017-01-01

    The bead on a rotating hoop is a typical problem in mechanics, frequently posed to junior science and engineering students in basic physics courses. Although this system has a rich dynamics, it is usually not analysed beyond the point particle approximation in undergraduate textbooks, nor empirically investigated. Advanced textbooks show the existence of bifurcations owing to the system's nonlinear nature, and some papers demonstrate, from a theoretical standpoint, its points of contact with phase transition phenomena. However, scarce experimental research has been conducted to better understand its behaviour. We show in this paper that a minor modification to the problem leads to appealing consequences that can be studied both theoretically and empirically with the basic conceptual tools and experimental skills available to junior students. In particular, we go beyond the point particle approximation by treating the bead as a rigid spherical body, and explore the effect of a slightly non-vertical hoop's rotation axis that gives rise to a resonant behaviour not considered in previous works. This study can be accomplished by means of digital video and open source software. The experience can motivate an engaging laboratory project by integrating standard curriculum topics, data analysis and experimental exploration.

  8. On the motion of Newtonian and non-Newtonian liquid filaments: Stretching, beading, blistering, pinching

    Science.gov (United States)

    Smolka, Linda Beth

    The motion and stability of a liquid filament drawn out behind a falling drop is examined experimentally and mathematically for Newtonian and non-Newtonian fluids. We confirm experimentally that an exact solution for the interfacial motion of an infinite Newtonian filament captures the thinning of the filament in experiments with several fluids. We also show experimentally that a linear stability analysis of this solution correctly predicts whether the filament end-pinches or internally-pinches, creating either one or several satellite drops. We derive an exact solution for a purely extensional cylindrical filament of non-Newtonian fluid that satisfies both the Upper Convected Maxwell and Oldroyd-B constitutive laws. The resulting prediction of decreasing filament thickness agrees with our experimental measurements for dilute polymer solutions. In the limit t → infinity, the exact solution approaches that for a Newtonian fluid. In experiments with a polyelectrolyte polymer (xanthan gum) solution, the drop length sensitively depends on the ionic strength of the solvent environment due to charge screening effects. We also study the "beadon-string" phenomenon, in which a nascent disturbance grows to finite size along a filament. In experiments with an aqueous polymer solution the perturbation grows logarithmically, and may saturate in size to a nearly spherical shape. Numerical simulations of a simple 1-D model for the bead predicts the logarithmic growth, but fail to capture saturation. Finally, in experiments with surfactant solutions composed of wormlike micelles, with low concentrations, the drop pinches-off in one location along the filament, and the free filament ends contract toward the orifice or drop. For higher concentrations, this free filament does not fully retract, instead it retains some of its deformation. The drop may also stall in its downward motion, such that elasticity balances the weight of the drop. For still higher concentration surfactant

  9. Strongly nonlinear waves in a chain of Teflon beads

    OpenAIRE

    Daraio, C.; Nesterenko, V. F.; Herbold, E. B.; Jin, S.

    2005-01-01

    One-dimensional “sonic vacuum” type phononic crystals were assembled from a chain of polytetrafluoroethylene (PTFE,Teflon) spheres with different diameters in a Teflon holder. It was demonstrated that this polymer-based sonic vacuum, with exceptionally low elastic modulus of particles, supports propagation of strongly nonlinear solitary waves with a very low speed. These solitary waves can be described using the classical nonlinear Hertz law despite the viscoelastic nature of the polymer and ...

  10. Selective removal of cesium by ammonium molybdophosphate – polyacrylonitrile bead and membrane

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Dahu, E-mail: ddh@njau.edu.cn [College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China); Graduate School of Life and Environmental Science, University of Tsukuba, Tsukuba, Ibaraki 305-8572 (Japan); Zhang, Zhenya [Graduate School of Life and Environmental Science, University of Tsukuba, Tsukuba, Ibaraki 305-8572 (Japan); Chen, Rongzhi [College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100044 (China); Cai, Tianming, E-mail: ctm@njau.edu.cn [College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China)

    2017-02-15

    Highlights: • AMP-PAN membrane was prepared for the first time through a simple way. • AMP-PAN bead performed high adsorption capacity and selectivity towards Cs{sup +}. • Liquid film diffusion was the rate-limiting step during the batch adsorption process. • AMP-PAN membrane could eliminate Cs{sup +} effectively from water through rapid filtration. - Abstract: The selective removal of radionuclides with extremely low concentrations from environmental medium remains a big challenge. Ammonium molybdophosphate possess considerable selectivity towards cesium ion (Cs{sup +}) due to the specific ion exchange between Cs{sup +} and NH{sub 4}{sup +}. Ammonium molybdophosphate – polyacrylonitrile (AMP-PAN) membrane was successfully prepared for the first time in this study. Efficient removal of Cs{sup +} (95.7%, 94.1% and 91.3% of 1 mg L{sup −1}) from solutions with high ionic strength (400 mg L{sup −1} of Na{sup +}, Ca{sup 2+} or K{sup +}) was achieved by AMP-PAN composite. Multilayer chemical adsorption process was testified through kinetic and isotherm studies. The estimated maximum adsorption capacities even reached 138.9 ± 21.3 mg g{sup −1}. Specifically, the liquid film diffusion was identified as the rate-limiting step throughout the removal process. Finally, AMP-PAN membrane could eliminate Cs{sup +} from water effectively through the filtration adsorption process.

  11. Effect of chromium speciation on its sorption mechanism onto grape stalks entrapped into alginate beads

    Directory of Open Access Journals (Sweden)

    Carlos Escudero

    2017-02-01

    Full Text Available Sorption of Cr(III and Cr(VI ions onto 2% grape stalk (GS powder entrapped in a biopolymeric gel matrix of calcium alginate (CA has been investigated and a mechanism for the retention of both, Cr(VI and Cr(III is proposed. Protons were found to be consumed in Cr(VI sorption/reduction and to compete with Cr(III for the sorbent active sites. Isotherm equilibrium was modelled according to Langmuir equation: maximum capacity was found to be 6.4 and 3.6 mg g−1 for Cr(III and Cr(VI, respectively. The important Ca2+ release observed when Cr(III is sorbed indicates that ion exchange is the main mechanism involved at concentrations lower than 200 mg L−1 while other mechanisms such as microprecipitation or coordination might take place for higher initial concentrations. In the case of Cr(VI, the sorption mechanism is based on the reduction to Cr(III promoted by both protons and the functional groups on the GS surface; this reduction-formed Cr(III is retained by the alginate gel matrix and by microprecipitation onto the surface of GS particles. ESR and SEM-EDX were used to identify chromium species sorbed on the solid phase. Results from this study suggest that GS entrapped in CA gel beads is an effective sorbent for both, Cr(III and Cr(VI removal from aqueous solutions.

  12. Effect on human platelet aggregation of phospholipase A2 purified from Heloderma horridum (beaded lizard) venom.

    Science.gov (United States)

    Huang, T F; Chiang, H S

    1994-02-10

    By means of gel filtration, ionic exchange chromatography and DEAE-column HPLC, an acidic phospholipase A2 (PLA2) was purified from beaded lizard (Heloderma horridum) venom. The purified PLA is a single-chain polypeptide, consisting of about 163 amino acid residues with a molecular mass of 19,000 Da as calculated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and amino acid analysis. HHV-PLA showed a rather specific inhibitory effect on platelet aggregation induced by U46619 and epinephrine in human platelet-rich plasma in a dose- and time-dependent manner, whereas it had little effect on collagen- and ADP-induced aggregation. ATP-release reaction induced by various agonists were dose- and time-dependently inhibited by HHV-PLA, even though platelet aggregation was apparently not affected in human washed platelets. When HHV-PLA was chemically modified with p-bromophenacyl bromide, both of its enzymatic activity and antiplatelet activity were lost. Furthermore, exogenous lysophosphatidylcholine and HHV-PLA treated phosphatidylcholine inhibited platelet aggregation induced by U46619 in human washed platelets. In conclusion, PLA enzyme from H. horridum venom inhibits exclusively U46619- or thromboxane-induced platelet aggregation of human platelet-rich plasma probably by virtue of their PLA enzymatic activity on plasma phospholipids, converting phospholipids (e.g., phosphatidylcholine) into lysophospholipids, which in turn interfere with the coupling of TXA2 receptor and its signalling transduction system.

  13. Isolation and characterization of helothermine, a novel toxin from Heloderma horridum horridum (Mexican beaded lizard) venom.

    Science.gov (United States)

    Mochca-Morales, J; Martin, B M; Possani, L D

    1990-01-01

    A protein toxic to mice was isolated from the venom of the Mexican beaded lizard Heloderma horridum horridum by a combination of gel filtration (Sephadex G-75) and ion exchange chromatography (both diethylaminoethyl-cellulose [DE-cellulose] and carboxymethyl-cellulose [CM-cellulose]). The purified polypeptide component has an apparent mol. wt of 25,500 and is composed of approximately 220 amino acid residues. It has an isoelectric point (pI) of 6.8 and its N-terminal amino acid sequence was shown to be: Glu-Ala-Ser-Pro-Lys-Leu-Pro-Gly-Leu-Met-Thr-Ser-Asn-Pro-Asp-Gln-Gln-Thr- Glu-Ile. The sequence has no significant similarity with any other protein previously reported in the literature. Enzymatic activities such as phospholipase, hyaluronidase and proteinase, commonly present in venoms, could not be demonstrated in this protein. Patch-clamp experiments conducted with excitable membranes show no effects on Na+, K+ or Ca2+ ion channels. Among the constant physiological effects observed in mice injected with this toxin are lethargy, partial paralysis of rear limbs and lowering of body temperature, suggesting that it might be a hypothermic toxin. We propose calling this toxin Helothermine.

  14. Heat exchangers

    International Nuclear Information System (INIS)

    1975-01-01

    The tubes of a heat exchanger tube bank have a portion thereof formed in the shape of a helix, of effective radius equal to the tube radius and the space between two adjacent tubes, to tangentially contact the straight sections of the tubes immediately adjacent thereto and thereby provide support, maintain the spacing and account for differential thermal expansion thereof

  15. Heat exchanger

    International Nuclear Information System (INIS)

    Wolowodiuk, W.

    1976-01-01

    A heat exchanger of the straight tube type is described in which different rates of thermal expansion between the straight tubes and the supply pipes furnishing fluid to those tubes do not result in tube failures. The supply pipes each contain a section which is of helical configuration

  16. Exchange Options

    NARCIS (Netherlands)

    Jamshidian, F.

    2007-01-01

    The contract is described and market examples given. Essential theoretical developments are introduced and cited chronologically. The principles and techniques of hedging and unique pricing are illustrated for the two simplest nontrivial examples: the classical Black-Scholes/Merton/Margrabe exchange

  17. Durability and Performance of Polystyrene-b-Poly(vinylbenzyl trimethylammonium) Diblock Copolymer and Equivalent Blend Anion Exchange Membranes

    Science.gov (United States)

    2015-01-01

    PS/PVBC, as the diblock copolymer. Film Formation The polymers in a powder form, or beads for PS, were mixed with toluene at a concentration of 0.3 g...mem- branes in 1M sodium bicarbonate solutions for 48 h. Standar- dized silver nitrate solution, 0.0235M, was used to titrate the membrane solutions

  18. Highly Sensitive Bacteria Quantification Using Immunomagnetic Separation and Electrochemical Detection of Guanine-Labeled Secondary Beads

    Directory of Open Access Journals (Sweden)

    Harikrishnan Jayamohan

    2015-05-01

    Full Text Available In this paper, we report the ultra-sensitive indirect electrochemical detection of E. coli O157:H7 using antibody functionalized primary (magnetic beads for capture and polyguanine (polyG oligonucleotide functionalized secondary (polystyrene beads as an electrochemical tag. Vacuum filtration in combination with E. coli O157:H7 specific antibody modified magnetic beads were used for extraction of E. coli O157:H7 from 100 mL samples. The magnetic bead conjugated E. coli O157:H7 cells were then attached to polyG functionalized secondary beads to form a sandwich complex (magnetic bead/E. coli secondary bead. While the use of magnetic beads for immuno-based capture is well characterized, the use of oligonucleotide functionalized secondary beads helps combine amplification and potential multiplexing into the system. The antibody functionalized secondary beads can be easily modified with a different antibody to detect other pathogens from the same sample and enable potential multiplexing. The polyGs on the secondary beads enable signal amplification up to 10\\(^{8}\\ guanine tags per secondary bead (\\(7.5\\times10^{6}\\ biotin-FITC per secondary bead, 20 guanines per oligonucleotide bound to the target (E. coli. A single-stranded DNA probe functionalized reduced graphene oxide modified glassy carbon electrode was used to bind the polyGs on the secondary beads. Fluorescent imaging was performed to confirm the hybridization of the complex to the electrode surface. Differential pulse voltammetry (DPV was used to quantify the amount of polyG involved in the hybridization event with tris(2,2'-bipyridineruthenium(II (Ru(bpy\\(_{3}^{2+}\\ as the mediator. The amount of polyG signal can be correlated to the amount of E. coli O157:H7 in the sample. The method was able to detect concentrations of E. coli O157:H7 down to 3 CFU/100 mL, which is 67 times lower than the most sensitive technique reported in literature. The signal to noise ratio for this work was 3

  19. Chinese and Venetian glass beads excavated from Fais Island in Micronesia

    International Nuclear Information System (INIS)

    Intoh, Michiko

    1997-01-01

    Full text: Over 830 glass beads were excavated from a late prehistoric cemetery site on Fais Island in the Caroline Islands, Micronesia In one of the 13 excavated burials a young woman had more that 310 glass beads around her wrist. Bone collagen from this burial was dated by AMS to 387 + 64 BP. The associated glass beads were classified into three groups based on colour and size. A sample from each group was examined for evidence of manufacturing technique. The chemical composition was determined using an X-ray microanalyser. The first group consisted of more than 300 pale green, transparent glass beads which are less than 2 mm in diameter. The chemical composition is high in PbO (75.22%) while low in MgO. Such a high lead content is characteristic of Chinese glass. The manufacturing technique could not be determined because the surfaces were too eroded. The second group contains several yellow, translucent glass beads. The chemical composition is also high in PbO (54.8%) and low in MgO. The beads were made by winding. The combination of winding and high lead strongly indicates that the beads were made in China. The third group had only one white, translucent glass bead. It has particular white stripes which suggest that it is a 'gooseberry' bead which was made in Venice between the sixteenth and eighteenth centuries. In conclusion, both Chinese and Venetian glass beads co-existed on Fais Island around the time of European contact. They are likely to have been brought in from an area which had access to both beads. Island South-East Asia is tentatively considered to be the source area

  20. Conducting Polymers

    Indian Academy of Sciences (India)

    backbone (by the process of doping) and make them electrically. Conducting Polymers. From a Laboratory Curiosity to the Market Place. S Ramakrishnan ..... switching occurs between transparent yellow and green in less than. 100ms. Thus, while these materials are yet to achieve the set target. (in terms of their life cycle) ...

  1. Conducting Polymers

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 16; Issue 12. Conducting Polymers - From a Laboratory Curiosity to the Market Place. S Ramakrishnan. Volume 16 Issue 12 December 2011 pp 1254-1265. Fulltext. Click here to view fulltext PDF. Permanent link:

  2. Polymer solutions

    Science.gov (United States)

    Krawczyk, Gerhard Erich [Bremen, DE; Miller, Kevin Michael [West Dundee, IL

    2011-07-26

    There is provided a method of making a polymer solution comprising polymerizing one or more monomer in a solvent, wherein said monomer comprises one or more ethylenically unsaturated monomer that is a multi-functional Michael donor, and wherein said solvent comprises 40% or more by weight, based on the weight of said solvent, one or more multi-functional Michael donor.

  3. Polymer physics

    CERN Document Server

    Gedde, Ulf W

    1999-01-01

    This book is the result of my teaching efforts during the last ten years at the Royal Institute of Technology. The purpose is to present the subject of polymer physics for undergraduate and graduate students, to focus the fundamental aspects of the subject and to show the link between experiments and theory. The intention is not to present a compilation of the currently available literature on the subject. Very few reference citations have thus been made. Each chapter has essentially the same structure: starling with an introduction, continuing with the actual subject, summarizing the chapter in 30D-500 words, and finally presenting problems and a list of relevant references for the reader. The solutions to the problems presented in Chapters 1-12 are given in Chapter 13. The theme of the book is essentially polymer science, with the exclusion of that part dealing directly with chemical reactions. The fundamentals in polymer science, including some basic polymer chemistry, are presented as an introduction in t...

  4. Supramolecular polymers

    National Research Council Canada - National Science Library

    Ciferri, A

    2000-01-01

    ... to the new class of self-assembled polymers that undergo reversible growth by the formation of noncovalent bonds. This class (Part II) is wider than expected: not only mainchain assemblies of hydrogen-bonded repeating units, but also planar organization of S-layer proteins, micellar and related three-dimensional structures of blo...

  5. Radionuclide Leaching from Organic Ion Exchange Resin

    International Nuclear Information System (INIS)

    Delegard, C.H.; Rinehart, D.E.

    1998-01-01

    Laboratory tests were performed to examine the efficacy of leach treatments for decontaminating organic ion exchange resins (OIER), which have been found in a number of samples retrieved from K East Basin sludge. Based on process records, the OIER found in the K Basins is a mixed-bet strong acid/strong base material marketed as Purolitetrademark NRW-037. Radionuclides sorbed or associated with the OIER can restrict its disposal to the Environmental Restoration Disposal Facility (ERDF). The need for testing to support development of a treatment process for K Basin sludge has been described in Section 4.2 of ''Testing Strategy to Support the Development of K Basins Sludge Treatment Process'' (Flament 1998). To help understand the effects of anticipated OIER elutriation and washing, tests were performed with well-rinsed OIER material from K East Basin floor sludge (sample H-08 BEAD G) and with well-rinsed OIER having approximately 5% added K East canister composite sludge (sample KECOMP). The rinsed resin-bearing material also contained the inorganic ion exchanger Zeolon-900trademark, a zeolite primarily composed of the mineral mordenite. The zeolite was estimated to comprise 27 weight percent of the dry H-08 BEAD G material

  6. Characterization of polymer adsorption onto drug nanoparticles using depletion measurements and small-angle neutron scattering.

    Science.gov (United States)

    Goodwin, Daniel J; Sepassi, Shadi; King, Stephen M; Holland, Simon J; Martini, Luigi G; Lawrence, M Jayne

    2013-11-04

    Production of polymer and/or surfactant-coated crystalline nanoparticles of water-insoluble drugs (nanosuspensions) using wet bead milling is an important formulation approach to improve the bioavailability of said compounds. Despite the fact that there are a number of nanosuspensions on the market, there is still a deficiency in the characterization of these nanoparticles where further understanding may lead to the rational selection of polymer/surfactant. To this end small-angle neutron scattering (SANS) measurements were performed on drug nanoparticles milled in the presence of a range of polymers of varying molecular weight. Isotopic substitution of the aqueous solvent to match the scattering length density of the drug nanoparticles (i.e., the technique of contrast matching) meant that neutron scattering resulted only from the adsorbed polymer layer. The layer thickness and amount of hydroxypropylcellulose adsorbed on nabumetone nanoparticles derived from fitting the SANS data to both model-independent and model dependent volume fraction profiles were insensitive to polymer molecular weight over the range Mv = 47-112 kg/mol, indicating that the adsorbed layer is relatively flat but with tails extending up to approximately 23 nm. The constancy of the absorbed amount is in agreement with the adsorption isotherm determined by measuring polymer depletion from solution in the presence of the nanoparticles. Insensitivity to polymer molecular weight was similarly determined using SANS measurements of nabumetone or halofantrine nanoparticles stabilized with hydroxypropylmethylcellulose or poly(vinylpyrrolidone). Additionally SANS studies revealed the amount adsorbed, and the thickness of the polymer layer was dependent on both the nature of the polymer and drug particle surface. The insensitivity of the adsorbed polymer layer to polymer molecular weight has important implications for the production of nanoparticles, suggesting that lower molecular weight polymers

  7. Thermodynamics and local structure of vinyl polymer melts

    International Nuclear Information System (INIS)

    Yethiraj, A.; Curro, J.G.; Rajasekaran, J.J.

    1995-01-01

    Monte Carlo simulation results are reported for the site-site pair correlations and equation of state of model vinyl polymer melts. The molecules are freely jointed hard chains with a hard sphere side-group attached to every other backbone bead. The local structure and pressure are investigated as a function of the diameter of the side group for melt-like densities. The intramolecular correlation functions are well represented by a single chain model where excluded volume interactions are included for beads separated by four bonds or less and neglected otherwise. The intermolecular correlation functions show interesting packing effects. The side group shields the backbone beads from approaching each other, to a degree that increases with increasing diameter of the side group. The polymer reference interaction site model integral equation theory is in good agreement with the simulation results for the pair correlation functions. At fixed volume fraction, the pressure is found to be a non-monotonic function of the size of the side group. copyright 1995 American Institute of Physics

  8. Super-Absorbent Polymer Gels for Oil and Grease Removal from Metal and Non-Metal Surfaces

    Science.gov (United States)

    2012-05-21

    morphology, phase transition, and functional groups of the synthesized polymers before the cleaning tests using: Infrared spectrometer ( FTIR ), UV... styrene based imbiber beads in various solvents 0 20 40 60 80 100 1 2 3 97.58 96.36 90.78 80.46 80.58 77.32 95.55 90.99 96.62 % oil

  9. Ion exchange equilibrium constants

    CERN Document Server

    Marcus, Y

    2013-01-01

    Ion Exchange Equilibrium Constants focuses on the test-compilation of equilibrium constants for ion exchange reactions. The book first underscores the scope of the compilation, equilibrium constants, symbols used, and arrangement of the table. The manuscript then presents the table of equilibrium constants, including polystyrene sulfonate cation exchanger, polyacrylate cation exchanger, polymethacrylate cation exchanger, polysterene phosphate cation exchanger, and zirconium phosphate cation exchanger. The text highlights zirconium oxide anion exchanger, zeolite type 13Y cation exchanger, and

  10. Heat exchanger

    International Nuclear Information System (INIS)

    Bennett, J.C.

    1975-01-01

    A heat exchanger such as forms, for example, part of a power steam boiler is made up of a number of tubes that may be arranged in many different ways, and it is necessary that the tubes be properly supported. The means by which the tubes are secured must be as simple as possible so as to facilitate construction and must be able to continue to function effectively under the varying operating conditions to which the heat exchanger is subject. The arrangement described is designed to meet these requirements, in an improved way. The tubes are secured to a member extending past several tubes and abutment means are provided. At least some of the abutment means comprise two abutment pieces and a wedge secured to the supporting member, that acts on these pieces to maintain the engagement. (U.K.)

  11. OBT analysis method using polyethylene beads for limited quantities of animal tissue

    International Nuclear Information System (INIS)

    Kim, S.B.; Stuart, M.

    2015-01-01

    This study presents a polyethylene beads method for OBT determination in animal tissues and animal products for cases where the amount of water recovered by combustion is limited by sample size or quantity. In the method, the amount of water recovered after combustion is enhanced by adding tritium-free polyethylene beads to the sample prior to combustion in an oxygen bomb. The method reduces process time by allowing the combustion water to be easily collected with a pipette. Sufficient water recovery was achieved using the polyethylene beads method when 2 g of dry animal tissue or animal product were combusted with 2 g of polyethylene beads. Correction factors, which account for the dilution due to the combustion water of the beads, are provided for beef, chicken, pork, fish and clams, as well as egg, milk and cheese. The method was tested by comparing its OBT results with those of the conventional method using animal samples collected on the Chalk River Laboratories (CRL) site. The results determined that the polyethylene beads method added no more than 25% uncertainty when appropriate correction factors are used. - Highlights: • Polyethylene beads method for OBT determination in animal tissues and animal products were determined. • The method reduces process time. • The polyethylene beads method added no more than 25% uncertainty when appropriate correction factors are used

  12. On-chip measurement of the Brownian relaxation frequency of magnetic beads using magnetic tunneling junctions

    DEFF Research Database (Denmark)

    Donolato, M.; Sogne, E.; Dalslet, Bjarke Thomas

    2011-01-01

    We demonstrate the detection of the Brownian relaxation frequency of 250 nm diameter magnetic beads using a lab-on-chip platform based on current lines for exciting the beads with alternating magnetic fields and highly sensitive magnetic tunnel junction (MTJ) sensors with a superparamagnetic free...

  13. Evaluation of the Seismic Characterision of Select Engineered Nanoparticles in Saturated Glass Beads

    Science.gov (United States)

    A laboratory testing apparatus was developed for the study of seismic body wave propagation through nanoparticles dispersed in pore fluid that is essentially saturating glass beads. First, the responses of water-saturated glass bead specimens were studied to establish baseline si...

  14. Planar Hall effect sensor bridge geometries optimized for magnetic bead detection

    DEFF Research Database (Denmark)

    Østerberg, Frederik Westergaard; Rizzi, Giovanni; Henriksen, Anders Dahl

    2014-01-01

    Novel designs of planar Hall effect bridge sensors optimized for magnetic bead detection are presented and characterized. By constructing the sensor geometries appropriately, the sensors can be tailored to be sensitive to an external magnetic field, the magnetic field due to beads being magnetized...

  15. Chemical–physical characterisation of Early Iron Age glass beads from Central Europe

    Energy Technology Data Exchange (ETDEWEB)

    Agua, F.; Conde, J.F.; Kobylińska, U.; Kobyliński, Z.; García-Heras, M.; Villegas, M.A.

    2017-07-01

    Archaeological excavation of the Institute of Archaeology and Ethnology (Polish Academy of Sciences, PAN) at several Iron Age sites located in West Poland and South Germany has allowed the recovery of an important set of coloured glass beads mostly decorated (6th–4th centuries BC). The present paper summarises the results obtained through the chemical and microstructural characterisation of such beads. The research was carried out by binocular microscope observations, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectrometry and visible spectrophotometry. The main objective was to attain information on the production technology and conservation state of these beads. The results indicated that all them were produced with soda lime silicate glass, even though two groups can be separated: (i) beads containing high MgO percentages made from plant ashes as an alkaline source, and (ii) beads containing low MgO percentages made from natron as an alkaline source. As regards decorations, opaque white was obtained from tin oxide, turquoise blue from Cu2+-ions, and opaque yellow from lead antimonate. Additionally, results showed microstructural and microcrystalline differences between some glass beads studied here and other glass beads from Mediterranean areas, dated in the same chronological period. This fact pointed out the valuable role given to these beads by Iron Age communities from Central Europe. (Author)

  16. Adipic acid dihydrazide treated partially oxidized alginate beads for sustained oral delivery of flurbiprofen.

    Science.gov (United States)

    Maiti, Sabyasachi; Singha, Kamalika; Ray, Somasree; Dey, Paramita; Sa, Biswanath

    2009-01-01

    In this study, periodate oxidation of sodium alginate was controlled such that the oxidized alginate could form isolatable beads with Ca(+2) ions. The beads of oxidized alginate having a degree of oxidation 1 mol%, entrapped 89% flurbiprofen and released almost all of its content within 1.5 h in pH 7.2 phosphate buffer solution. The beads were covalently crosslinked with adipic dihydrazide (ADH) in addition to ionic crosslinks and were characterized. Scanning electron microscopy revealed that the beads were spherical having smooth surfaces. The drug entrapment efficiency decreased (90-86%) with increasing concentration of ADH (2-6% w/v) in the gelation medium. However, the beads prolonged the drug release in alkaline dissolution medium up to 8 h depending upon the concentration of ADH. The beads prepared with 2% ADH swelled more rapidly and led to faster drug release in either pH 1.2 HCl solution or pH 7.2 phosphate buffer solution. The swelling tendencies were reduced and the drug release became slower with higher concentrations in either fluid. The drug diffusion from the beads followed super case II transport mechanism. FTIR spectroscopy indicated stable nature of flurbiprofen in the beads and therefore had potential as sustained oral delivery system for the drug.

  17. Development of bioactive porous α-TCP/HAp beads for bone tissue engineering.

    Science.gov (United States)

    Asaoka, Teruo; Ohtake, Shoji; Furukawa, Katsuko S; Tamura, Akito; Ushida, Takashi

    2013-11-01

    Porous beads of bioactive ceramics such as hydroxyapatite (HAp) and tribasic calcium phosphate (TCP) are considered a promising scaffold for cultivating bone cells. To realize this, α-TCP/HAp functionally graded porous beads are fabricated with two main purposes: to maintain the function of the scaffold with sufficient strength up to the growth of new bone, and is absorbed completely after the growth. HAp is a bioactive material that has both high strength and strong tissue-adhesive properties, but is not readily absorbed by the human body. On the contrary, α-TCP is highly bioabsorbable, resulting in a scaffold that is absorbed before it is completely replaced by bone. In this study, we produced porous, bead-shaped carriers as scaffolds for osteoblast culture. To control the solubility in vivo, the fabricated beads contained α-TCP at the center and HAp at the surface. Cell adaptability of these beads for bone tissue engineering was confirmed in vitro. It was found that α-TCP/HAp bead carriers exhibit low toxicity in the initial stages of cell seeding and cell adhesion. The presence of HAp in the composite bead form effectively increased ALP activity. In conclusion, it is suggested that these newly developed α-TCP/HAp beads are a promising tool for bone tissue engineering. Copyright © 2013 Wiley Periodicals, Inc.

  18. Magnetic nanoparticle-loaded alginate beads for local micro-actuation of in vitro tissue constructs.

    Science.gov (United States)

    Alshehri, Awatef M; Wilson, Otto C; Dahal, Bishnu; Philip, John; Luo, Xiaolong; Raub, Christopher B

    2017-11-01

    Magnetic nanoparticles (MNPs) self-align and transduce magnetic force, two properties which lead to promising applications in cell and tissue engineering. However, the toxicity of MNPs to cells which uptake them is a major impediment to applications in engineered tissue constructs. To address this problem, MNPs were embedded in millimeter-scale alginate beads, coated with glutaraldehyde cross-linked chitosan, and loaded in acellular and MDA-MB-231 cancer cell-seeded collagen hydrogels, providing local micro-actuation under an external magnetic field. Brightfield microscopy was used to assess nanoparticle diffusion from the bead. Phase contrast microscopy and digital image correlation were used to track collagen matrix displacement and estimate intratissue strain under magnetic actuation. Coating the magnetic alginate beads with glutaraldehyde-chitosan prevents bulk diffusion of nanoparticles into the surrounding microenvironment. Further, the beads exert force on the surrounding collagen gel and cells, resulting in intratissue strains of 0-10% tunable with bead dimensions, collagen density, and distance from the bead. Cells seeded adjacent to the embedded beads are subjected to strain gradients without loss of cell viability over two days culture. This study describes a simple way to fabricate crosslinked magnetic alginate beads to load in a collagen tissue construct without direct exposure of the construct to nanoparticles. The findings are significant to in vitro studies of mechanobiology in enabling precise control over dynamic mechanical loading of tissue constructs. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Membranes of MnO Beading in Carbon Nanofibers as Flexible Anodes for High-Performance Lithium-Ion Batteries

    Science.gov (United States)

    Zhao, Xin; Du, Yuxuan; Jin, Lei; Yang, Yang; Wu, Shuilin; Li, Weihan; Yu, Yan; Zhu, Yanwu; Zhang, Qinghua

    2015-01-01

    Freestanding yet flexible membranes of MnO/carbon nanofibers are successfully fabricated through incorporating MnO2 nanowires into polymer solution by a facile electrospinning technique. During the stabilization and carbonization processes of the as-spun membranes, MnO2 nanowires are transformed to MnO nanoparticles coincided with a conversion of the polymer from an amorphous state to a graphitic structure of carbon nanofibers. The hybrids consist of isolated MnO nanoparticles beading in the porous carbon and demonstrate superior performance when being used as a binder-free anode for lithium-ion batteries. With an optimized amount of MnO (34.6 wt%), the anode exhibits a reversible capacity of as high as 987.3 mAh g−1 after 150 discharge/charge cycles at 0.1 A g−1, a good rate capability (406.1 mAh g−1 at 3  A g−1) and an excellent cycling performance (655 mAh g−1 over 280 cycles at 0.5 A g−1). Furthermore, the hybrid anode maintains a good electrochemical performance at bending state as a flexible electrode. PMID:26374601

  20. SparseBeads data: benchmarking sparsity-regularized computed tomography

    DEFF Research Database (Denmark)

    Jørgensen, Jakob Sauer; Coban, Sophia B.; Lionheart, William R. B.

    2017-01-01

    Sparsity regularization (SR) such as total variation (TV) minimization allows accurate image reconstruction in x-ray computed tomography (CT) from fewer projections than analytical methods. Exactly how few projections suffice and how this number may depend on the image remain poorly understood....... Compressive sensing connects the critical number of projections to the image sparsity, but does not cover CT, however empirical results suggest a similar connection. The present work establishes for real CT data a connection between gradient sparsity and the sufficient number of projections for accurate TV......, number of projections and noise levels to allow the systematic assessment of parameters affecting performance of SR reconstruction algorithms6. Using the SparseBeads data, TV-regularized reconstruction quality was assessed as a function of numbers of projections and gradient sparsity. The critical number...

  1. Adherence between steel bars and lightweight concrete with EPS beads

    Directory of Open Access Journals (Sweden)

    A. L. SARTORI

    Full Text Available Abstract This paper describes the adherence behavior of a structural lightweight concrete with EPS beads (SLCEB in a monotonic loading, based in a bibliographic review and in pull-out tests. The results of these SLCEB tests were compared with those of an ordinary concrete (OC and with the values based in indications of the Brazilian code ABNT NBR 6118:2014 - Design of concrete structures. The pull-out tests of two batches of SLCEB and one of OC were analyzed, in a total of 60 tests. Mechanical characteristics were determined too, such as: compressive strength and tensile strength in split cylinder test. The calculated results according to the above mentioned standard were very different from those obtained in the tests, indicating that the theoretical values are more conservative than the experimental ones. It was also verified that it is possible to use SLCEB in structures with respect to the adequate adherence of reinforcement in the concrete.

  2. Aligned Porous Beads Prepared by Frozen Polymerization of Emulsion-Templates Involving Tiny Emulsifier

    Directory of Open Access Journals (Sweden)

    Lu Zhen

    2016-01-01

    Full Text Available High internal phase emulsion (HIPE templated porous materials are attracting increasing interests due to its high porosity and tunable structure. However, large amounts (5-50 vol% of suitable non-ionic surfactants are commonly required to stabilize conventional HIPE due to the high internal volume fraction of HIPE. In this work, applying frozen polymerization in HIPE, aligned porous beads were prepared with tiny surfactant (~0.1 wt%. These interconnected aligned porous beads were prepared through directional freezing, and frozen ultraviolet (UV initiation of an oil-in-water (o/w HIPE. The HIPEs are extruded by needle, and then directionally frozen in liquid nitrogen to form beads. The frozen beads were exposed under UV irradiation in a -20 °C ethanol bath to initiate the monomers in the aqueous phase. Moreover, the morphology of the resulting porous beads were tailored by vary the ratio of oil/water and the amount of emulsifier.

  3. Investigation on rare earth magnets recycling by organophosphoric extractant encapsulated polymeric beads for separation of dysprosium

    International Nuclear Information System (INIS)

    Yadav, Kartikey K.; Singh, D.K.; Kain, V.

    2017-01-01

    Rare earth elements (REEs) are a basic requirement of the electronics and new industries including green technology. In the present work an organophosphoric extractant encapsulating polyethersulfone (PES) beads has been developed and employed for dysprosium (Dy) separation from aqueous stream. Polyethersulfonic beads encapsulating PC88A were prepared by phase inversion method. During the synthesis of the beads, preparatory parameters were also optimized to obtain best suited beads which were subsequently characterized for their encapsulation capacity and micro structural investigation. The results obtained in the present investigation suggested that PES/PVAJPC88A composite beads could be used for separation of rare earths from aqueous medium obtained from the solubilisation of magnetic scrap materials

  4. Preparation and Characterization of Highly Spherical Silica-titania Aerogel Beads with High Surface Area

    Directory of Open Access Journals (Sweden)

    YU Yu-xi

    2017-02-01

    Full Text Available The silica-titania aerogel beads were synthesized through sol-gel reaction followed by supercritical drying, in which TEOS and TBT as co-precursors, EtOH as solvents, HAC and NH3·H2O as catalysts. The as-prepared aerogel beads were characterized by SEM,TEM,XRD,FT-IR,TG-DTA and nitrogen adsorption-desorption. The results indicate that the diameter distribution of beads are between 1-8mm, the average diameter of beads is 3.5mm. The aerogel beads have nanoporous network structure with high specific surface area of 914.5m2/g, and the TiO2 particles are distributed in the aerogel uniformly, which keep the anatase crystal under high temperature.

  5. Development and Evaluation of Dual Cross-Linked Pulsatile Beads for Chronotherapy of Rheumatoid Arthritis

    Directory of Open Access Journals (Sweden)

    Abanesh kumar Bansal

    2013-01-01

    Full Text Available In the present investigation, pulsatile release beads were prepared by ionic gelation technique. Lornoxicam dual cross-linked beads were prepared by dropping dispersed phase of lornoxicam, pectin, and sodium alginate into the dispersion phase of different concentrations of calcium chloride solution followed by aluminium chloride solution. The formulated beads were further coated by Eudragit L & S 100 in the ratio 1 : 2 w/w in order to achieve desired lag time. In vitro release study showed lag time of 5–8 h before release of lornoxicam from the formulated beads. Thus, formulated dual cross-linked beads when administered at bed time may release lornoxicam when needed most for chronotherapeutics of early morning rheumatoid arthritis attacks in chronic patients.

  6. Echicetin coated polystyrene beads: a novel tool to investigate GPIb-specific platelet activation and aggregation.

    Directory of Open Access Journals (Sweden)

    Alexey Navdaev

    Full Text Available von Willebrand factor/ristocetin (vWF/R induces GPIb-dependent platelet agglutination and activation of αIIbβ3 integrin, which also binds vWF. These conditions make it difficult to investigate GPIb-specific signaling pathways in washed platelets. Here, we investigated the specific mechanisms of GPIb signaling using echicetin-coated polystyrene beads, which specifically activate GPIb. We compared platelet activation induced by echicetin beads to vWF/R. Human platelets were stimulated with polystyrene beads coated with increasing amounts of echicetin and platelet activation by echicetin beads was then investigated to reveal GPIb specific signaling. Echicetin beads induced αIIbβ3-dependent aggregation of washed platelets, while under the same conditions vWF/R treatment led only to αIIbβ3-independent platelet agglutination. The average distance between the echicetin molecules on the polystyrene beads must be less than 7 nm for full platelet activation, while the total amount of echicetin used for activation is not critical. Echicetin beads induced strong phosphorylation of several proteins including p38, ERK and PKB. Synergistic signaling via P2Y12 and thromboxane receptor through secreted ADP and TxA2, respectively, were important for echicetin bead triggered platelet activation. Activation of PKG by the NO/sGC/cGMP pathway inhibited echicetin bead-induced platelet aggregation. Echicetin-coated beads are powerful and reliable tools to study signaling in human platelets activated solely via GPIb and GPIb-triggered pathways.

  7. Composite inorganic ion exchangers and their uses

    International Nuclear Information System (INIS)

    Sebesta, F.; John, J.; Motl, A.

    1998-01-01

    Composite inorganic ion exchangers are described containing modified polyacrylonitrile as the binding polymer. An overview of existing composite ion exchangers is presented, and the universality and assets of the developed procedure of treatment of inorganic ion exchanger powders are highlighted. Examples of applicability of the ion exchangers to the separation and concentration of radionuclides include in particular: wastes from the operation of nuclear power plants, contaminated surface waters and ground water, high level radioactive wastes from spent fuel reprocessing, and wastewaters from uranium ore mining and milling. In addition, composite ion exchangers find use in the monitoring of contamination of the hydrosphere and the environment and in the investigation of radionuclide migration in surface waters and ground water

  8. Polymer blends

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Scott D.; Naik, Sanjeev

    2017-08-22

    The present invention provides, among other things, extruded blends of aliphatic polycarbonates and polyolefins. In one aspect, provided blends comprise aliphatic polycarbonates such as poly(propylene carbonate) and a lesser amount of a crystalline or semicrystalline polymer. In certain embodiments, provided blends are characterized in that they exhibit unexpected improvements in their elongation properties. In another aspect, the invention provides methods of making such materials and applications of the materials in applications such as the manufacture of consumer packaging materials.

  9. Thermomechanical response and toughening mechanisms of a carbon nano bead reinforced epoxy composite

    Energy Technology Data Exchange (ETDEWEB)

    Goyat, M.S., E-mail: goyatmanjeetsingh@gmail.com [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Roorkee, Roorkee, 247667 (India); Suresh, Sumit; Bahl, Sumit [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Roorkee, Roorkee, 247667 (India); Halder, Sudipta [Department of Mechanical Engineering, National Institute of Technology, Silchar, 788010, Assam (India); Ghosh, P.K. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Roorkee, Roorkee, 247667 (India)

    2015-09-15

    The current research on carbon nano beads (CNB) is focused on various applications such as high strength nanocomposites, electronic devices, lubricants, semiconductors, and high-performance batteries, etc. The commercial uses of CNB are yet juvenile for the market. Only limited results have been published so far on CNB reinforced polymers [1]. This study highlights the synthesis of uniform size, spherical CNB using chemical vapour deposition (CVD) method. The synthesized CNB are introduced into epoxy matrix by ultrasonic dual mode mixing route to produce CNB/epoxy nanocomposite. The CNB are characterized by X-ray diffraction, Energy dispersive X-ray analysis and field emission scanning electron microscope (FESEM). Morphology, thermal and mechanical properties of the CNB/epoxy nanocomposites is characterized by FESEM, Thermo-gravimetric analyzer and tensile and bending tests respectively. A noticeable improvement in thermal and mechanical properties of CNB reinforced epoxy matrix with low nanofiller content is observed. Several toughening mechanisms such as particle pull out, crack deflection, particle bridging, crack pinning, shear yielding or plastic deformation, and microcracking are identified. But, only the crack deflection, particle bridging and shear yielding or plastic deformations are recognized as the leading toughening mechanisms for CNB/epoxy nanocomposite. These results can be considered as symptomatic of a potential CNB espousal in new composites. - Highlights: • Synthesis of uniform size, spherical CNB using chemical vapour deposition method. • Fabrication of CNB/epoxy nanocomposites by ultrasonic dual mode mixing route. • Significant enhancement in thermomechanical properties of CNB/epoxy nanocomposite. • Main toughening mechanisms: Crack deflection, particle bridging and shear yielding.

  10. Effect of hydroxide polymenrs on cation exchange of montmorillonite

    NARCIS (Netherlands)

    Janssen, R.P.T.; Bruggenwert, M.G.M.; Riemsdijk, van W.H.

    2003-01-01

    Al hydroxide polymers (AlHO) can significantly influence the cation exchange behaviour of clays. We have determined the effect of synthesized AlHO on Ca¿Na, Zn¿Na and Pb¿Na exchange for a series of exchanger compositions and two Al loadings at pH 6.0 and an ionic strength of 0.01 m. The preference

  11. Mechanical and tribological studies of polymer hybrid ...

    Indian Academy of Sciences (India)

    Administrator

    It is observed that wear rate increases with increasing applied load, time and sliding speeds. Keywords. Halloysite clay ... stability at higher loads, temperatures, better lubrication and wear properties (Vinson and Chou 1975; ... cation exchange capacity and polymer matrix) used and the method of preparation (Park et al ...

  12. Neutron activation analysis of AD 1660-1930 European copper-coloured blue glass trade beads from Ontario, Canada

    International Nuclear Information System (INIS)

    Kenyon, I.; Hancock, R.G.V.; Aufreiter, S.

    1995-01-01

    Blue glass trade beads from well-dated late seventeenth- to early twentieth-century sites and collections have been analysed non-destructively by instrumental neutron activation analysis. The beads display enough variations in their elemental contents to allow us to characterize the different chemistries. The implication of these results is that similar chemical analyses of blue beads from undated archaeological sites may be used to help date the sites, since each bead chemistry has a specific earliest period. (author)

  13. Exchanging information

    International Nuclear Information System (INIS)

    1971-01-01

    The Agency has a statutory mandate to foster 'the exchange of scientific and technical information on the peaceful uses of atomic energy'. The prime responsibility for this work within the Agency lies with the Division of Scientific and Technical Information, a part of the Department of Technical Operations. The Division accomplishes its task by holding conferences and symposia (Scientific Conferences Section), through the Agency Library, by publishing scientific journals, and through the International Nuclear Information System (INIS). The Computer Section of the Division, which offers services to the Agency as a whole, provides resources for the automation of data storage and retrieval. (author)

  14. Evaluation of polyacrylonitrile (PAN) as a binding polymer for absorbers used to treat liquid radioactive wastes

    International Nuclear Information System (INIS)

    Sebesta, F.; John, J.; Motl, A.; Stamberg, K.

    1995-11-01

    The chemical and radiation stability of polyacrylonitrile (PAN) in the form of beads (B-PAN), similar to the beads of composite absorbers, and one selected composite absorber (ammonium molybdophosphate, the active component in PAN binder [AMP-PAN], a prospective candidate for the treatment of acidic wastes) were studied. Aqueous 1M HNO 3 + 1M NaNO 3 , 1M NaOH + 1M NaNO 3 , and 1M NaOH were chosen as simulants of DOE acidic and alkaline wastes. In addition,radiation stability was determined indistilled water. The chemical stability of B-PAN and AMP-PAN beads was tested for a period up to one month of contact with the solution at ambient temperature. The radiation stability of the beads was checked in a radiation dose range 10 3 --10 6 Gy (10 5 --10 8 rads). In acidic solutions the stability of PAN binder was proved not to be limited by either chemical or radiation decomposition. PAN binder may thus be used for preparing composite absorbers for treatment of acid wastes from DOE facilities. The same conclusion is valid for alkaline solutions with pH up to 13. In highly alkaline solutions (concentration of NAOH higher than I M) and in the presence of NaNO 3 , the stability of the tested polyacrylonitrile polymer was sufficient for applications not extending over 10 days. Cross-linking of the polymer caused by ionizing radiation was found to have a positive influence on chemical stability. This effect enables a longer period of applicability of PAN-based composite absorbers. Because of the high sorption rate achievable with PAN-based absorbers, the stability achieved is sufficient for most applications in the DOE complex. The chemical stability of binding polymer may also be further improved by testing another, more suitable type of polymer from the broad family of polyacrylonitrile polymers

  15. Antibacterial and wound healing properties of chitosan/poly(vinyl alcohol)/zinc oxide beads (CS/PVA/ZnO).

    Science.gov (United States)

    Gutha, Yuvaraja; Pathak, Janak L; Zhang, Weijiang; Zhang, Yaping; Jiao, Xu

    2017-10-01

    Treatment against bacterial infection is crucial for wound healing. Development of cost-effective antibacterial agent with wound healing properties is still in high demand. In this study we aimed to design chitosan/poly(vinyl alcohol)/zinc oxide (CS/PVA/ZnO) beads as novel antibacterial agent with wound healing properties. CS/PVA/ZnO beads were synthesized, and characterized by using XRD, FTIR, SEM, and TEM analysis. Pure chitosan exhibits two peaks at 2θ=10 and 20 and the CS/PVA polymer matrix exhibit the peaks at 2θ=19.7° and another of low intensity at 2θ=11.5°. Pure ZnO shows the characteristic peaks at (100), (002), (101), (102), (110), (103), (200), and (112) that were in good agreement with wurtzite ore having hexagonal lattice structure. The antibacterial activity of CS/PVA/ZnO against Escherichia coli, and Staphylococcus aureus were evaluated with the zone of inhibition method. Antibacterial activity of CS/PVA/ZnO was higher than that of chitosan (CS) and poly(vinyl alcohol (PVA). Hemocompatibility and biocompatibility of CS/PVA/ZnO were tested in in vitro. Wound healing properties of CS/PVA/ZnO were tested in mice skin wound. CS/PVA/ZnO showed strong antimicrobial, wound healing effect, hemocompatibility and biocompatibility. Hence the results strongly support the possibility of using this novel CS/PVA/ZnO material for the anti bacterial and wound healing application. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Efficient functionalization of poly(styrene) beads immobilized metal ...

    Indian Academy of Sciences (India)

    Now the removal of the textile dyes in waste water dis- charge from various industries such as the textile, ... Therefore, removal of colour from waste water is a major environmental problem and threat to the society. ..... 20. Youk J H 2003 Polymer 44 5053. 21. SeshadriS,BishopPLandAghaAM1994 Waste Manage 14 127. 22.

  17. Matchmaker Exchange.

    Science.gov (United States)

    Sobreira, Nara L M; Arachchi, Harindra; Buske, Orion J; Chong, Jessica X; Hutton, Ben; Foreman, Julia; Schiettecatte, François; Groza, Tudor; Jacobsen, Julius O B; Haendel, Melissa A; Boycott, Kym M; Hamosh, Ada; Rehm, Heidi L

    2017-10-18

    In well over half of the individuals with rare disease who undergo clinical or research next-generation sequencing, the responsible gene cannot be determined. Some reasons for this relatively low yield include unappreciated phenotypic heterogeneity; locus heterogeneity; somatic and germline mosaicism; variants of uncertain functional significance; technically inaccessible areas of the genome; incorrect mode of inheritance investigated; and inadequate communication between clinicians and basic scientists with knowledge of particular genes, proteins, or biological systems. To facilitate such communication and improve the search for patients or model organisms with similar phenotypes and variants in specific candidate genes, we have developed the Matchmaker Exchange (MME). MME was created to establish a federated network connecting databases of genomic and phenotypic data using a common application programming interface (API). To date, seven databases can exchange data using the API (GeneMatcher, PhenomeCentral, DECIPHER, MyGene2, matchbox, Australian Genomics Health Alliance Patient Archive, and Monarch Initiative; the latter included for model organism matching). This article guides usage of the MME for rare disease gene discovery. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley and Sons, Inc.

  18. Preparation of Silk Sericin/Lignin Blend Beads for the Removal of Hexavalent Chromium Ions.

    Science.gov (United States)

    Kwak, Hyo Won; Shin, Munju; Yun, Haesung; Lee, Ki Hoon

    2016-09-02

    In the present study, novel adsorbents having high adsorption capability and reusability were prepared using agricultural by-products: silk sericin and lignin. Silk sericin and lignin blend beads were successfully prepared using simple coagulation methods for the removal of hexavalent chromium (Cr(VI)) from aqueous solution. A 1 M lithium chloride (LiCl)/dimethyl sulfoxide (DMSO) solvent system successfully dissolved both sericin and lignin and had sufficient viscosity for bead preparation. Compared to the conventional sericin bead adsorbent, sericin/lignin blend beads showed higher Cr(VI) adsorption capacity. The amount of lignin added to the adsorbent greatly affected the adsorption capacity of the beads, and a 50:50 sericin/lignin blend ratio was optimal. Adsorption behavior followed the Freundlich isotherm, which means the adsorption of Cr(VI) occurred on the heterogeneous surface. Cr(VI) adsorption capability increased with temperature because of thermodynamic-kinetic effects. In addition, over 90% of Cr(VI) ions were recovered from the Cr(VI) adsorbed sericin/lignin beads in a 1 M NaOH solution. The adsorption-desorption recycling process was stable for more than seven cycles, and the recycling efficiency was 82%. It is expected that the sericin/lignin beads could be successfully applied in wastewater remediation especially for hazardous Cr(VI) ions in industrial wastewater.

  19. Preparation of Silk Sericin/Lignin Blend Beads for the Removal of Hexavalent Chromium Ions

    Directory of Open Access Journals (Sweden)

    Hyo Won Kwak

    2016-09-01

    Full Text Available In the present study, novel adsorbents having high adsorption capability and reusability were prepared using agricultural by-products: silk sericin and lignin. Silk sericin and lignin blend beads were successfully prepared using simple coagulation methods for the removal of hexavalent chromium (Cr(VI from aqueous solution. A 1 M lithium chloride (LiCl/dimethyl sulfoxide (DMSO solvent system successfully dissolved both sericin and lignin and had sufficient viscosity for bead preparation. Compared to the conventional sericin bead adsorbent, sericin/lignin blend beads showed higher Cr(VI adsorption capacity. The amount of lignin added to the adsorbent greatly affected the adsorption capacity of the beads, and a 50:50 sericin/lignin blend ratio was optimal. Adsorption behavior followed the Freundlich isotherm, which means the adsorption of Cr(VI occurred on the heterogeneous surface. Cr(VI adsorption capability increased with temperature because of thermodynamic-kinetic effects. In addition, over 90% of Cr(VI ions were recovered from the Cr(VI adsorbed sericin/lignin beads in a 1 M NaOH solution. The adsorption-desorption recycling process was stable for more than seven cycles, and the recycling efficiency was 82%. It is expected that the sericin/lignin beads could be successfully applied in wastewater remediation especially for hazardous Cr(VI ions in industrial wastewater.

  20. Preparation of Silk Sericin/Lignin Blend Beads for the Removal of Hexavalent Chromium Ions

    Science.gov (United States)

    Kwak, Hyo Won; Shin, Munju; Yun, Haesung; Lee, Ki Hoon

    2016-01-01

    In the present study, novel adsorbents having high adsorption capability and reusability were prepared using agricultural by-products: silk sericin and lignin. Silk sericin and lignin blend beads were successfully prepared using simple coagulation methods for the removal of hexavalent chromium (Cr(VI)) from aqueous solution. A 1 M lithium chloride (LiCl)/dimethyl sulfoxide (DMSO) solvent system successfully dissolved both sericin and lignin and had sufficient viscosity for bead preparation. Compared to the conventional sericin bead adsorbent, sericin/lignin blend beads showed higher Cr(VI) adsorption capacity. The amount of lignin added to the adsorbent greatly affected the adsorption capacity of the beads, and a 50:50 sericin/lignin blend ratio was optimal. Adsorption behavior followed the Freundlich isotherm, which means the adsorption of Cr(VI) occurred on the heterogeneous surface. Cr(VI) adsorption capability increased with temperature because of thermodynamic-kinetic effects. In addition, over 90% of Cr(VI) ions were recovered from the Cr(VI) adsorbed sericin/lignin beads in a 1 M NaOH solution. The adsorption-desorption recycling process was stable for more than seven cycles, and the recycling efficiency was 82%. It is expected that the sericin/lignin beads could be successfully applied in wastewater remediation especially for hazardous Cr(VI) ions in industrial wastewater. PMID:27598142

  1. Decolourisation of dyes under electro-Fenton process using Fe alginate gel beads

    International Nuclear Information System (INIS)

    Rosales, E.; Iglesias, O.; Pazos, M.; Sanromán, M.A.

    2012-01-01

    Highlights: ► Catalytic activity of Fe alginate gel beads for the remediation of wastewater was tested. ► New electro-Fenton process for the remediation of polluted wastewater. ► Continuous dye treatment without operational problem with high removal. - Abstract: This study focuses on the application of electro-Fenton technique by use of catalytic activity of Fe alginate gel beads for the remediation of wastewater contaminated with synthetic dyes. The Fe alginate gel beads were evaluated for decolourisation of two typical dyes, Lissamine Green B and Azure B under electro-Fenton process. After characterization of Fe alginate gel beads, the pH effect on the process with Fe alginate beads and a comparative study of the electro-Fenton process with free Fe and Fe alginate bead was done. The results showed that the use of Fe alginate beads increases the efficiency of the process; moreover the developed particles show a physical integrity in a wide range of pH (2–8). Around 98–100% of dye decolourisation was obtained for both dyes by electro-Fenton process in successive batches. Therefore, the process was performed with Fe alginate beads in a bubble continuous reactor. High color removal (87–98%) was attained for both dyes operating at a residence time of 30 min, without operational problems and maintaining particle shapes throughout the oxidation process. Consequently, the stable performance of Fe alginate beads opens promising perspectives for fast and economical treatment of wastewater polluted by dyes or similar organic contaminants.

  2. Decolourisation of dyes under electro-Fenton process using Fe alginate gel beads

    Energy Technology Data Exchange (ETDEWEB)

    Rosales, E.; Iglesias, O.; Pazos, M. [Department of Chemical Engineering, University of Vigo, Isaac Newton Building, Campus As Lagoas, Marcosende 36310, Vigo (Spain); Sanroman, M.A., E-mail: sanroman@uvigo.es [Department of Chemical Engineering, University of Vigo, Isaac Newton Building, Campus As Lagoas, Marcosende 36310, Vigo (Spain)

    2012-04-30

    Highlights: Black-Right-Pointing-Pointer Catalytic activity of Fe alginate gel beads for the remediation of wastewater was tested. Black-Right-Pointing-Pointer New electro-Fenton process for the remediation of polluted wastewater. Black-Right-Pointing-Pointer Continuous dye treatment without operational problem with high removal. - Abstract: This study focuses on the application of electro-Fenton technique by use of catalytic activity of Fe alginate gel beads for the remediation of wastewater contaminated with synthetic dyes. The Fe alginate gel beads were evaluated for decolourisation of two typical dyes, Lissamine Green B and Azure B under electro-Fenton process. After characterization of Fe alginate gel beads, the pH effect on the process with Fe alginate beads and a comparative study of the electro-Fenton process with free Fe and Fe alginate bead was done. The results showed that the use of Fe alginate beads increases the efficiency of the process; moreover the developed particles show a physical integrity in a wide range of pH (2-8). Around 98-100% of dye decolourisation was obtained for both dyes by electro-Fenton process in successive batches. Therefore, the process was performed with Fe alginate beads in a bubble continuous reactor. High color removal (87-98%) was attained for both dyes operating at a residence time of 30 min, without operational problems and maintaining particle shapes throughout the oxidation process. Consequently, the stable performance of Fe alginate beads opens promising perspectives for fast and economical treatment of wastewater polluted by dyes or similar organic contaminants.

  3. Metallic Bead Detection by Using Eddy-Current Probe with SV-GMR Sensor

    International Nuclear Information System (INIS)

    Yamada, S.; Chomsuwan, K.; Hagino, T.; Iwahara, M.; Tian, H.

    2005-01-01

    The progress of the ECT probe with micro magnetic sensor becomes possible to apply to various applications. The detection of micro metallic bead used for electric packaging has been reported in this paper. We proposed micro ECT probes with meander coil as exciter and spin-valve giant magneto-resistance (SV-GMR) as receiver. Micro metallic bead(solder ball) with the diameter of 0.25 to 0.76 mm is used as a measuring object. We discuss the detection and alignment of metallic bead by using ECT technique

  4. Effect of Buffers on Aqueous Solute-Exclusion Zones around Ion-Exchange Resins

    Science.gov (United States)

    Zheng, Jian-ming; Wexler, Adam

    2009-01-01

    Interaction between charged surfaces in aqueous solution is a fundamental feature of colloid science. Theoretically, surface potential falls to half its value at a distance equal to a Debye length, which is typically on the order of tens to hundreds of nanometers. This potential prevents colloids from aggregating. On the other hand, long-range surface effects have been frequently reported. Here we report additional long-range effects. We find that charged latex particles in buffer solutions are uniformly excluded from several-hundred-micron-thick shells surrounding ion-exchange beads. Exclusion is observed whether the beads are charged similarly or oppositely to the particles. Hence, electrostatic interactions between bead and microsphere do not cause particle exclusion. Rather, exclusion may be the consequence of water molecules re-orienting to produce a more ordered structure, which then excludes the particles. PMID:19185312

  5. Searching for low percolation thresholds within amphiphilic polymer membranes: The effect of side chain branching

    Science.gov (United States)

    Dorenbos, G.

    2015-06-01

    Percolation thresholds for solvent diffusion within hydrated model polymeric membranes are derived from dissipative particle dynamics in combination with Monte Carlo (MC) tracer diffusion calculations. The polymer backbones are composed of hydrophobic A beads to which at regular intervals Y-shaped side chains are attached. Each side chain is composed of eight A beads and contains two identical branches that are each terminated with a pendant hydrophilic C bead. Four types of side chains are considered for which the two branches (each represented as [C], [AC], [AAC], or [AAAC]) are splitting off from the 8th, 6th, 4th, or 2nd A bead, respectively. Water diffusion through the phase separated water containing pore networks is deduced from MC tracer diffusion calculations. The percolation threshold for the architectures containing the [C] and [AC] branches is at a water volume fraction of ˜0.07 and 0.08, respectively. These are much lower than those derived earlier for linear architectures of various side chain length and side chain distributions. Control of side chain architecture is thus a very interesting design parameter to decrease the percolation threshold for solvent and proton transports within flexible amphiphilic polymer membranes.

  6. Pulsed laser manipulation of an optically trapped bead: Averaging thermal noise and measuring the pulsed force amplitude

    DEFF Research Database (Denmark)

    Lindballe, Thue Bjerring; Kristensen, Martin V. G.; Keiding, Søren Rud

    2013-01-01

    -bead interaction is repeated hundreds of times. Traces with the bead position following the prompt displacement from equilibrium, induced by each laser pulse, are averaged and reveal the underlying deterministic motion of the bead, which is not visible in a single trace due to thermal noise. The motion of the bead...... is analyzed from the direct time-dependent position measurements and from the power spectrum. The results show that the bead is on average displaced 208 nm from the trap center and exposed to a force amplitude of 71 nanoNewton, more than five orders of magnitude larger than the trapping forces. Our...

  7. Role of special cross-links in structure formation of bacterial DNA polymer

    Science.gov (United States)

    Agarwal, Tejal; Manjunath, G. P.; Habib, Farhat; Lakshmi Vaddavalli, Pavana; Chatterji, Apratim

    2018-01-01

    Using data from contact maps of the DNA-polymer of Escherichia coli (E. Coli) (at kilobase pair resolution) as an input to our model, we introduce cross-links between monomers in a bead-spring model of a ring polymer at very specific points along the chain. Via suitable Monte Carlo simulations, we show that the presence of these cross-links leads to a particular organization of the chain at large (micron) length scales of the DNA. We also investigate the structure of a ring polymer with an equal number of cross-links at random positions along the chain. We find that though the polymer does get organized at the large length scales, the nature of the organization is quite different from the organization observed with cross-links at specific biologically determined positions. We used the contact map of E. Coli bacteria which has around 4.6 million base pairs in a single circular chromosome. In our coarse-grained flexible ring polymer model, we used 4642 monomer beads and observed that around 80 cross-links are enough to induce the large-scale organization of the molecule accounting for statistical fluctuations caused by thermal energy. The length of a DNA chain even of a simple bacterial cell such as E. Coli is much longer than typical proteins, hence we avoided methods used to tackle protein folding problems. We define new suitable quantities to identify the large scale structure of a polymer chain with a few cross-links.

  8. Segmented heat exchanger

    Science.gov (United States)

    Baldwin, Darryl Dean; Willi, Martin Leo; Fiveland, Scott Byron; Timmons, Kristine Ann

    2010-12-14

    A segmented heat exchanger system for transferring heat energy from an exhaust fluid to a working fluid. The heat exchanger system may include a first heat exchanger for receiving incoming working fluid and the exhaust fluid. The working fluid and exhaust fluid may travel through at least a portion of the first heat exchanger in a parallel flow configuration. In addition, the heat exchanger system may include a second heat exchanger for receiving working fluid from the first heat exchanger and exhaust fluid from a third heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the second heat exchanger in a counter flow configuration. Furthermore, the heat exchanger system may include a third heat exchanger for receiving working fluid from the second heat exchanger and exhaust fluid from the first heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the third heat exchanger in a parallel flow configuration.

  9. QCM-nanomagnetic beads biosensor for lead ion detection.

    Science.gov (United States)

    Zhang, Qingli; Cui, Haixia; Xiong, Xingliang; Chen, Jun; Wang, Ying; Shen, Jia; Luo, Yiting; Chen, Longcong

    2018-01-15

    As lead poses a serious threat to humans even in small amounts, all kinds of lead detection sensors with high sensitivity and selectivity are being constantly improved and put forward. In this report, a novel, simple and label-free quartz crystal microbalance (QCM) biosensor is proposed for detecting lead ions (Pb 2+ ). The biosensor takes full advantage of the high specificity of GR-5 DNAzyme to Pb 2+ and the high sensitivity of QCM. In particular, nanomagnetic beads (NMBs) are used as a novel and effective mean of signal amplification in the biosensor because of their mass and their ability to enhance the inductive effect, which are very beneficial for both higher sensitivity and a lower detection limit. In practice, GR-5 DNAzyme, innovatively combined with NMBs, was modified on the gold electrode of the QCM through gold-sulfur self-assembly. When the electrode was exposed to Pb 2+ solution, DNAzyme was severed into two parts at the RNA site (rA), along with the release of NMBs, which caused a great increase in frequency shift of the QCM electrode. Finally, a perfect linear correlation between the logarithm of Pb 2+ concentration and the change in frequency was obtained from 1 pM to 50 nM, with a detection limit as low as 0.3 pM. Moreover, the biosensor shows both an average recovery of 97 ± 6% in a drinking water sample and an excellent specificity for Pb 2+ compared with other metal ions.

  10. Interfacial Friction and Adhesion of Polymer Brushes

    KAUST Repository

    Landherr, Lucas J. T.

    2011-08-02

    A bead-probe lateral force microscopy (LFM) technique is used to characterize the interfacial friction and adhesion properties of polymer brushes. Our measurements attempt to relate the physical structure and chemical characteristics of the brush to their properties as thin-film, tethered lubricants. Brushes are synthesized at several chain lengths and surface coverages from polymer chains of polydimethylsiloxane (PDMS), polystyrene (PS), and a poly(propylene glycol)-poly(ethylene glycol) block copolymer (PPG/PEG). At high surface coverage, PDMS brushes manifest friction coefficients (COFs) that are among the lowest recorded for a dry lubricant film (μ ≈ 0.0024) and close to 1 order of magnitude lower than the COF of a bare silicon surface. Brushes synthesized from higher molar mass chains exhibit higher friction forces than those created using lower molar mass polymers. Increased grafting density of chains in the brush significantly reduces the COF by creating a uniform surface of stretched chains with a decreased surface viscosity. Brushes with lower surface tension and interfacial shear stresses manifest the lowest COF. In particular, PDMS chains exhibit COFs lower than PS by a factor of 3.7 and lower than PPG/PEG by a factor of 4.7. A scaling analysis conducted on the surface coverage (δ) in relation to the fraction (ε) of the friction force developing from adhesion predicts a universal relation ε ∼ δ4/3, which is supported by our experimental data. © 2011 American Chemical Society.

  11. Proteomic profiling of renal allograft rejection in serum using magnetic bead-based sample fractionation and MALDI-TOF MS.

    Science.gov (United States)

    Sui, Weiguo; Huang, Liling; Dai, Yong; Chen, Jiejing; Yan, Qiang; Huang, He

    2010-12-01

    Proteomics is one of the emerging techniques for biomarker discovery. Biomarkers can be used for early noninvasive diagnosis and prognosis of diseases and treatment efficacy evaluation. In the present study, the well-established research systems of ClinProt Micro solution incorporated unique magnetic bead sample preparation technology, which, based on matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), have become very successful in bioinformatics due to its outstanding performance and reproducibility for discovery disease-related biomarker. We collected fasting blood samples from patients with biopsy-confirmed acute renal allograft rejection (n = 12), chronic rejection (n = 12), stable graft function (n = 12) and also from healthy volunteers (n = 13) to study serum peptidome patterns. Specimens were purified with magnetic bead-based weak cation exchange chromatography and analyzed with a MALDI-TOF mass spectrometer. The results indicated that 18 differential peptide peaks were selected as potential biomarkers of acute renal allograft rejection, and 6 differential peptide peaks were selected as potential biomarkers of chronic rejection. A Quick Classifier Algorithm was used to set up the classification models for acute and chronic renal allograft rejection. The algorithm models recognize 82.64% of acute rejection and 98.96% of chronic rejection episodes, respectively. We were able to identify serum protein fingerprints in small sample sizes of recipients with renal allograft rejection and establish the models for diagnosis of renal allograft rejection. This preliminary study demonstrated that proteomics is an emerging tool for early diagnosis of renal allograft rejection and helps us to better understand the pathogenesis of disease process.

  12. Removal of hexavalent chromium from aqueous solution by barium ion cross-linked alginate beads

    Directory of Open Access Journals (Sweden)

    Uzaşçı Sesil

    2014-07-01

    Full Text Available Barium ion cross-linked alginate beads have shown great affinity to toxic hexavalent chromium ions in aqueous solution, contrary to the traditional calcium alginate beads. The adsorption experiments were carried out by the batch contact method. The optimal pH for removal was found to be pH 4. The equilibrium was established in 4 h and the removal efficiency of chromium (VI was found as 95%. The adsorption data fit well with Langmuir and Freundlich isotherms. The maximum chromium (VI adsorption capacity determined from Langmuir isotherm was 36.5 mg/g dry alginate beads. Our study suggests that barium alginate beads can be used as cost-effective and efficient adsorbents for the removal of chromium (VI from contaminated waters.

  13. Glass bead cultivation of fungi: combining the best of liquid and agar media.

    Science.gov (United States)

    Droce, Aida; Sørensen, Jens Laurids; Giese, Henriette; Sondergaard, Teis Esben

    2013-09-01

    Production of bioactive compounds and enzymes from filamentous fungi is highly dependent on cultivation conditions. Here we present an easy way to cultivate filamentous fungi on glass beads that allow complete control of nutrient supply. Secondary metabolite production in Fusarium graminearum and Fusarium solani cultivated on agar plates, in shaking liquid culture or on glass beads was compared. Agar plate culture and glass bead cultivation yielded comparable results while liquid culture had lower production of secondary metabolites. RNA extraction from glass beads and liquid cultures was easier than from agar plates and the quality was superior. The system allows simple control of nutrient availability throughout fungal cultivation. This combined with the ease of extraction of nucleic acids and metabolites makes the system highly suitable for the study of gene regulation in response to specific nutrient factors. © 2013.

  14. Immobilization of catalase on chitosan and amino acid- modified chitosan beads.

    Science.gov (United States)

    Başak, Esra; Aydemir, Tülin

    2013-08-01

    Bovine liver catalase was covalently immobilized onto amino acid-modified chitosan beads. The beads were characterized with SEM, FTIR, TGA and the effects of immobilization on optimum pH and temperature, thermostability, reusability were evaluated. Immobilized catalase showed the maximal enzyme activity at pH 7.0 at 30°C. The kinetic parameters, Km and Vmax, for immobilized catalase on alanine-chitosan beads and lysine-chitosan beads were estimated to be 25.67 mM, 27 mM and 201.39 μmol H2O2/min, 197.50 μmol H2O2/min, respectively. The activity of the immobilized catalase on Ala-CB and Lys-CB retained 40% of its high initial activity after 100 times of reuse.

  15. Investigation the influence of dietary fiber on the rheological properties of alginate beads

    Directory of Open Access Journals (Sweden)

    Z. Manev

    2015-03-01

    Full Text Available Abstract. During the current investigation experiments for the preparation of alginate beads with aqueous solutions of sodium alginate, calcium lactate or calcium dichloride and dietary fiber in different concentrations: inulin with varying degrees of polymerization, wheat bran and amidated apple pectin were carried out. The sodium alginate solutions were at constant concentration 3%, while calcium salts in 7% were applied for bead formation. It was proven that the rupture force of alginate beads was always higher than the pure model system regardless of the chemical structure of dietary fibers used. In the result of the carried research the dependence at a certain concentration was established at which the rupture force and deformation of the beads increased gradually.

  16. Preparations of bifunctional polymeric beads simultaneously incorporated with fluorescent quantum dots and magnetic nanocrystals

    International Nuclear Information System (INIS)

    Tu Chifeng; Yang Yunhua; Gao Mingyuan

    2008-01-01

    Bifunctional polystyrene beads simultaneously incorporated with fluorescent CdTe quantum dots (Q-dots) and superparamagnetic Fe 3 O 4 nanocrystals were prepared by a modified mini-emulsion polymerization method, in which polymerizable surfactants were used as both phase transfer agent for aqueous colloidal nanoparticles and emulsifier. In addition, silica coating was also introduced to Fe 3 O 4 nanocrystals for regulating the internal structure of the composite beads. Transmission electron microscopy, confocal fluorescence microscopy and conventional spectroscopy were used to characterize the composite beads, as well as the polymerizable surfactant-coated CdTe Q-dots and silica-coated Fe 3 O 4 nanoparticles. Different mixing methods were also attempted in order to vary the size of the resultant bifunctional beads

  17. CUTANEOUS SQUAMOUS CELL CARCINOMA IN A PANTHER CHAMELEON (FURCIFER PARDALIS) AND TREATMENT WITH CARBOPLATIN IMPLANTABLE BEADS.

    Science.gov (United States)

    Johnson, James G; Naples, Lisa M; Chu, Caroline; Kinsel, Michael J; Flower, Jennifer E; Van Bonn, William G

    2016-09-01

    A 3-yr-old male panther chameleon (Furcifer pardalis) presented with bilateral raised crusted skin lesions along the lateral body wall that were found to be carcinoma in situ and squamous cell carcinoma. Similar lesions later developed on the caudal body wall and tail. A subcutaneous implantable carboplatin bead was placed in the first squamous cell carcinoma lesion identified. Additional new lesions sampled were also found to be squamous cell carcinomas, and viral polymerase chain reaction was negative for papillomaviruses and herpesviruses. Significant skin loss would have resulted from excision of all the lesions, so treatment with only carboplatin beads was used. No adverse effects were observed. Lesions not excised that were treated with beads decreased in size. This is the first description of cutaneous squamous cell carcinoma and treatment with carboplatin implantable beads in a panther chameleon.

  18. Synthesis and characterization of chitosan impregnated calcium alginate beads for removal of uranium from aquatic stream

    International Nuclear Information System (INIS)

    Singhal, R.K.; Basu, H.; Manisha, V.; Reddy, A.V.R.; Sawant, Manjiri; Kamane, Suman

    2015-01-01

    The present study was conducted to study the feasibility of chitosan impregnated calcium alginate beads (Cal-Alg-Chi) to sorb the excess uranium from the aquatic stream. Chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). The optimal composition of calcium alginate chitosan beads is 4 % (wt/vol) alginate gel having 5% loading of chitosan. The nature and morphology of pure and uranium sorbed calcium alginate chitosan beads were characterized by scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS), and attenuated total reflectance Fourier transform infrared spectroscopy (ATRFTIR). The results of batch sorption experiments suggest that Cal-Alg-Chi beads are very effective for removal of uranium in the pH range of 2.0-5.0 and sorption is more than 80 % in the concentration range of 1-100 mgL -1

  19. Asynchronous Magnetic Bead Rotation (AMBR Microviscometer for Label-Free DNA Analysis

    Directory of Open Access Journals (Sweden)

    Yunzi Li

    2014-03-01

    Full Text Available We have developed a label-free viscosity-based DNA detection system, using paramagnetic beads as an asynchronous magnetic bead rotation (AMBR microviscometer. We have demonstrated experimentally that the bead rotation period is linearly proportional to the viscosity of a DNA solution surrounding the paramagnetic bead, as expected theoretically. Simple optical measurement of asynchronous microbead motion determines solution viscosity precisely in microscale volumes, thus allowing an estimate of DNA concentration or average fragment length. The response of the AMBR microviscometer yields reproducible measurement of DNA solutions, enzymatic digestion reactions, and PCR systems at template concentrations across a 5000-fold range. The results demonstrate the feasibility of viscosity-based DNA detection using AMBR in microscale aqueous volumes.

  20. [DNA extraction from decomposed tissue by double-digest and magnetic beads methods].

    Science.gov (United States)

    Yang, Dian; Liu, Chao; Liu, Hong

    2011-12-01

    To study the effect of the double-digest and magnetic beads method for DNA extraction from 3 types of decomposed tissues. DNA of cartilages, nails and joint capsule in 91 highly decomposed corpses which had not been extracted by common magnetic beads method, were prepared with the double-digest and magnetic beads methods, and quantified with Quantifiler kit, followed by amplification with Sinofiler kit or Minifiler kit. DNA concentration extracted from the 91 highly decomposed cartilages, nails and joint capsule samples was 0-0.225 ng/microL. Sixty-two samples whose DNA concentration were more than 0.020 ng/microL had obtained 9 or more STR loci successfully. The detection rate was 68.13%. The successful rate of STR genotyping for the 3 types of decomposed tissues can be significantly improved by the double-digest and magnetic beads methods.

  1. An Attempt to Shorten Loading Time of Epirubicin into DC Beads{sup ®} Using Vibration and a Sieve

    Energy Technology Data Exchange (ETDEWEB)

    Sonoda, Akinaga, E-mail: akinagasonoda@yahoo.co.jp; Nitta, Norihisa [Shiga University of Medical Science, Department of Radiology (Japan); Yamamoto, Takefumi [Shiga University of Medical Science, Central Research Laboratory (Japan); Tomozawa, Yuki; Ohta, Shinichi; Watanabe, Shobu; Murata, Kiyoshi [Shiga University of Medical Science, Department of Radiology (Japan)

    2017-04-15

    PurposeWe investigated the possibility of shortening the time required for loading epirubicin into calibrated polyvinyl alcohol-based hydrogel beads (DC Beads{sup ®}) to be used for transarterial chemoembolization.MethodAfter separating the beads suspended in phosphate-buffered saline (PBS) solution by the use of a sieve (clearance 75 µm), epirubicin hydrochloride (EH) was loaded for 20, 30, or 60 s under vibration into DC beads. The EH loading rate into conventionally prepared (control) beads, i.e., beads loaded for 30 min without vibration, and vibration-loaded beads were calculated from the residual EH concentration in the bead-depleted EH solution. The amount of EH eluted from conventionally and vibration-loaded samples into a PBS solution (pH 7.0) was measured at 15 and 30 min and 1, 2, 6, 12, and 24 h. We also recorded the inhibitory effect of the PBS solution on the loading time. Using frozen sections, the EH load in the beads was evaluated visually under a fluorescence microscope.ResultsSpectrophotometry (495 nm) showed that the loading rate was 98.98 ± 0.34, 99.02 ± 0.32, and 99.50 ± 0.11 % with 20-, 30-, and 60-s vibration, respectively. The eluted rate was statistically similar between vibration- and statically loaded (control) beads. The PBS solution hampered EH loading into the beads. Visually, the distribution of EH in conventionally and vibration-loaded DC beads was similar.DiscussionThe use of vibration and the removal of PBS solution when epirubicin hydrochloride was loaded into DC beads dramatically shortened the loading time of epirubicin hydrochloride into DC beads.

  2. An Attempt to Shorten Loading Time of Epirubicin into DC Beads®Using Vibration and a Sieve.

    Science.gov (United States)

    Sonoda, Akinaga; Nitta, Norihisa; Yamamoto, Takefumi; Tomozawa, Yuki; Ohta, Shinichi; Watanabe, Shobu; Murata, Kiyoshi

    2017-04-01

    We investigated the possibility of shortening the time required for loading epirubicin into calibrated polyvinyl alcohol-based hydrogel beads (DC Beads ® ) to be used for transarterial chemoembolization. After separating the beads suspended in phosphate-buffered saline (PBS) solution by the use of a sieve (clearance 75 µm), epirubicin hydrochloride (EH) was loaded for 20, 30, or 60 s under vibration into DC beads. The EH loading rate into conventionally prepared (control) beads, i.e., beads loaded for 30 min without vibration, and vibration-loaded beads were calculated from the residual EH concentration in the bead-depleted EH solution. The amount of EH eluted from conventionally and vibration-loaded samples into a PBS solution (pH 7.0) was measured at 15 and 30 min and 1, 2, 6, 12, and 24 h. We also recorded the inhibitory effect of the PBS solution on the loading time. Using frozen sections, the EH load in the beads was evaluated visually under a fluorescence microscope. Spectrophotometry (495 nm) showed that the loading rate was 98.98 ± 0.34, 99.02 ± 0.32, and 99.50 ± 0.11 % with 20-, 30-, and 60-s vibration, respectively. The eluted rate was statistically similar between vibration- and statically loaded (control) beads. The PBS solution hampered EH loading into the beads. Visually, the distribution of EH in conventionally and vibration-loaded DC beads was similar. The use of vibration and the removal of PBS solution when epirubicin hydrochloride was loaded into DC beads dramatically shortened the loading time of epirubicin hydrochloride into DC beads.

  3. Anchorage Dependent Cells Attached to a Polymer

    Science.gov (United States)

    2004-01-01

    Biomedical research offers hope for a variety of medical problems, from diabetes to the replacement of damaged bone and tissues. Bioreactors, which are used to grow cells and tissue cultures, play a major role in such research and production efforts. Anchorage dependent cells on STS-95 will be grown on beads similar to these cells produced during previous investigations. Recombinant proteins may offer the possibility of reducing or eliminating transplant rejections. Research by Synthecon, Inc. using the BioDyn Bioreactor will focus on the preliminary process for growing a proprietary recombinant protein that can decrease rejection of transplanted tissue. The cells producing this protein are anchorage dependent, meaning that they must attach to something to grow. These cells will be cultured in the bioreactor in a medium containing polymer microbeads. Synthecon hopes that the data from this mission will lead to the development of a commercial protein that will aid in prevention of transplant rejection.

  4. Integrated polymer waveguides for absorbance detection in chemical analysis systems

    DEFF Research Database (Denmark)

    Mogensen, Klaus Bo; El-Ali, Jamil; Wolff, Anders

    2003-01-01

    A chemical analysis system for absorbance detection with integrated polymer waveguides is reported for the first time. The fabrication procedure relies on structuring of a single layer of the photoresist SU-8, so both the microfluidic channel network and the optical components, which include planar...... waveguides and fiber-to-waveguide coupler structures, are defined in the same processing step. This results in self-alignment of all components and enables a fabrication and packaging time of only one day. The fabrication scheme has recently been presented elsewhere for fluorescence excitation of beads...

  5. Immobilization of Lipase from Candida rugosa on Chitosan Beads for Transesterification Reaction

    OpenAIRE

    M. Nasratun; H. A. Said; A. Noraziah; A. N.A. Alla

    2009-01-01

    Problem statement: Further study is recommended to improve the immobilization technique and the immobilized lipases performance as catalysis in transesterification reaction. Approach: To investigate the ability of immobilized lipase on chitosan beads to catalyze the transesterification of cooking oil to an ester. The porous bead of chitosan was used for immobilization of lipase from Candida rugosa by physical adsorption. Parameters like reaction time and oil to methanol molar ratios were stud...

  6. Biosorption of nonylphenol on dead biomass of Rhizopus arrhizus encapsulated in chitosan beads

    OpenAIRE

    Lang, Weeranuch; Dejma, Chomawan; Sirisansaneeyakul, Sarote; Sakairi, Nobuo

    2009-01-01

    The nonylphenol (NP) biosorption and desorption potential for fungal biomass used under batch conditions was investigated using kinetics and isotherm models. Fungal biomass of Rhizopus arrhizus TISTR 3610 exhibited preferential uptake of NP, an endocrine disrupting chemicals. Sporangiospores, asexual spores, were immobilisation in chitosan beads. The biosorption data of NP on the moist heat inactivated R. arrhizus-chitosan beads were analyzed using four popular adsorption isotherms and, by us...

  7. Hematology, blood chemistry, and bacteriology of the free-ranging Mexican beaded lizard (Heloderma horridum).

    Science.gov (United States)

    Espinosa-Avilés, David; Salomón-Soto, Víctor Manuel; Morales-Martínez, Socorro

    2008-03-01

    Blood samples from 16 adult, wild Mexican beaded lizards were obtained for complete blood count and serum biochemical analysis. In addition, both oral and cloacal swab samples were collected and submitted for bacteriologic culture. This is the first report of hematologic and bacterial data from free-living beaded lizards. This information will serve as baseline reference values for future health assessment studies in conservation, captive breeding, and research programs.

  8. Comparative Study on Bacteria Colonization onto Ceramic Beads Originated from Two Devonian Clay Deposits in Latvia

    OpenAIRE

    Muter, O; Potapova, K; Nikolajeva, V; Petrina, Z; Griba, T; Patmalnieks, A; Švinka, R; Švinka, V

    2012-01-01

    Ceramic carriers for immobilization of microorganisms are widely used in wastewater treatment, air biofiltration technologies, etc. The aim of this study was to compare seven different types of ceramic beads fabricated from two types of Devonian clay, in terms of their appropriateness for bacteria cell attachment and further use for soil/air cleaning technologies. The effect of different ceramic beads on the microbial growth and biofilm formation was studied for pure c...

  9. Quantification of immiscible fluid distribution of an oil-wet and water-wet bead pack imaged using x-ray computed microtomography

    Science.gov (United States)

    Landry, C. J.; Karpyn, Z. T.; Piri, M.

    2009-12-01

    Classically, multiphase flow and transport is described using macroscopic properties, such as relative permeability and capillary pressure; these macroscopic properties are the result of pore-scale processes dictated by pore space morphology, fluid-fluid interactions and fluid-rock interactions. Characterization of pore-scale processes requires fundamental quantitative measurements, such as fluid surface areas, fluid-fluid interfacial areas, fluid-solid interfacial areas and fluid volume distribution. Many methods have been developed over the past couple of decades that allow for the noninvasive imaging of porous media, particularly, many past investigations have found great success using x-ray computed tomography to produce 3D images of pore space morphology and fluid distribution. The objective of this study is to obtain quantitative measurements at the pore-scale utilizing x-ray computed microtomography (CMT). In this investigation 0.425 - 0.600 mm diameter spherical acrylic polymer beads are packed into a vertically-oriented x-ray transparent column to represent an oil-wet porous medium. The bead packs are subjected to a sequence of drainage and imbibition cycles, utilizing 6-8 wt % KI solution and kerosene as the fluid phases. On select imbibitions and drainages the entirety of the bead pack is scanned by CMT, by scanning the entire bead pack fluid distribution throughout the bead pack, including the extent of systematic boundary effects, can be investigated. The results of this investigation are compared to a previous investigation carried out in a nearly identical fashion utilizing water-wet silica beads. The wetting-phase saturation profiles along the vertical axis of the bead packs show zones of fluid distribution. Drainage wetting phase saturation profiles show a zone of irreducible wetting phase saturation followed by a capillary transition zone terminated by a boundary affected zone; imbibition wetting phase profiles show both a zone of no saturation

  10. From commodity polymers to functional polymers.

    Science.gov (United States)

    Xiang, Tao; Wang, Ling-Ren; Ma, Lang; Han, Zhi-Yuan; Wang, Rui; Cheng, Chong; Xia, Yi; Qin, Hui; Zhao, Chang-Sheng

    2014-04-08

    Functional polymers bear specified chemical groups, and have specified physical, chemical, biological, pharmacological, or other uses. To adjust the properties while keeping material usage low, a method for direct synthesis of functional polymers is indispensable. Here we show that various functional polymers can be synthesized by in situ cross-linked polymerization/copolymerization. We demonstrate that the polymers synthesized by the facile method using different functional monomers own outstanding pH-sensitivity and pH-reversibility, antifouling property, antibacterial, and anticoagulant property. Our study opens a route for the functionalization of commodity polymers, which lead to important advances in polymeric materials applications.

  11. Capture, isolation and release of cancer cells with aptamer-functionalized glass bead array.

    Science.gov (United States)

    Wan, Yuan; Liu, Yaling; Allen, Peter B; Asghar, Waseem; Mahmood, M Arif Iftakher; Tan, Jifu; Duhon, Holli; Kim, Young-tae; Ellington, Andrew D; Iqbal, Samir M

    2012-11-21

    Early detection and isolation of circulating tumor cells (CTC) can enable better prognosis for cancer patients. A Hele-Shaw device with aptamer functionalized glass beads is designed, modeled, and fabricated to efficiently isolate cancer cells from a cellular mixture. The glass beads are functionalized with anti-epidermal growth factor receptor (EGFR) aptamer and sit in ordered array of pits in polydimethylsiloxane (PDMS) channel. A PDMS encapsulation is then used to cover the channel and to flow through cell solution. The beads capture cancer cells from flowing solution depicting high selectivity. The cell-bound glass beads are then re-suspended from the device surface followed by the release of 92% cells from glass beads using combination of soft shaking and anti-sense RNA. This approach ensures that the cells remain in native state and undisturbed during capture, isolation and elution for post-analysis. The use of highly selective anti-EGFR aptamer with the glass beads in an array and subsequent release of cells with antisense molecules provide multiple levels of binding and release opportunities that can help in defining new classes of CTC enumeration devices.

  12. Use of micrometric latex beads to improve the porosity of hydroxyapatite obtained by chemical coprecipitation method

    Science.gov (United States)

    Webler, G. D.; Rodrigues, W. C.; Silva, A. E. S.; Silva, A. O. S.; Fonseca, E. J. S.; Degenhardt, M. F. S.; Oliveira, C. L. P.; Otubo, L.; Barros Filho, D. A.

    2018-04-01

    Hydroxyapatite is one of the most important biomaterials whose application mainly extends to implants and drug delivery. This work will discuss the changes in the pore size distribution of hydroxyapatite when there are latex beads present during the synthesis. These changes were monitored using different techniques: small angle X-ray scattering, X-ray diffraction, thermal gravimetrical analysis, N2 adsorption, scanning and transmission electron microscopy. Latex beads and hydroxyapatite form a single nanocomposite with well-distinguished inorganic and organic phases. Latex bead removal in the temperature range of 300-600 °C did not modify the original crystalline structure of hydroxyapatite. However, the latex beads favored an increase in the adsorption capacity of mesopores at temperatures higher than their glassy transition (Tg). The main result of this research work consists on the increase of surface area and pore size distribution obtained after the removal of latex beads template. Latex beads have been used in a different approach changing the porosity of hydroxyapatite scaffolds not only introducing new routes for cell integration but also broadening the pore size distribution which can result in a more high efficiency for drug release in living cells.

  13. Tamarind seed polysaccharide-gellan mucoadhesive beads for controlled release of metformin HCl.

    Science.gov (United States)

    Nayak, Amit Kumar; Pal, Dilipkumar; Santra, Kousik

    2014-03-15

    The paper describes the development, optimization and evaluation of tamarind seed polysaccharide (TSP)-blended gellan gum (GG) mucoadhesive beads containing metformin HCl through Ca(2+)-ion cross-linked ionic gelation for oral drug delivery. Effects of GG to TSP ratio and cross-linker (CaCl2) concentration on the drug encapsulation efficiency (DEE, %), and cumulative drug release after 10h (R10h, %) of TSP-GG mucoadhesive beads containing metformin HCl were optimized by 32 factorial design. The optimized mucoadhesive beads (F-O) showed DEE of 95.73 ± 4.02%, R10h of 61.22 ± 3.44% and mean diameter of 1.70 ± 0.24 mm.These beads were characterized by SEM and FTIR analyses. The in vitro drug release from these beads showed controlled-release (zero-order) pattern over a period of 10h.The optimized TSP-GG mucoadhesive beads also exhibited pH-dependent swelling, good mucoadhesivity with biological mucosal membrane and significant hypoglycemic effect in alloxan-induced diabetic rats over prolonged period after oral administration. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Calcium pectinate-fenugreek seed mucilage mucoadhesive beads for controlled delivery of metformin HCl.

    Science.gov (United States)

    Nayak, Amit Kumar; Pal, Dilipkumar; Das, Sabinesh

    2013-07-01

    Calcium pectinate-fenugreek seed mucilage (FSM) mucoadhesive beads containing metformin HCl was developed through ionic-gelation. Effects of pectin and FSM amounts on drug encapsulation efficiency (DEE) and cumulative drug release at 10h (R10 h) were optimized using 3(2) factorial design. The DEE (%) was within the range of 63.16 ± 2.88 to 96.03 ± 4.67% (w/w). The in vitro drug release from these beads (56.64 ± 1.47 to 93.63 ± 4.52% over 10h) was followed controlled-release (zero-order) pattern (R(2)=0.993 to 0.997) with super case-II transport mechanism. The average size of beads was within 1.47 ± 0.14 to 2.08 ± 0.18 mm. The beads were also characterized by SEM and FTIR. The swelling and mucoadhesivity of these beads were influenced by pH of the medium. The optimized beads also exhibited good mucoadhesivity and significant hypoglycemic effect in alloxan-induced diabetic rats over prolonged period after oral administration. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Utility of expanded polystyrene (EPS) beads in the control of vector-borne diseases.

    Science.gov (United States)

    Sivagnaname, N; Amalraj, D Dominic; Mariappan, T

    2005-10-01

    The use of chemicals or bio-larvicides for the control of Culex quinquefasciatus and Anopheles stephensi breeding in pit latrines and overhead tanks (OHT) respectively is discouraged owing to many undesirable impacts in the environment. Due to faecal contamination and poor survival, use of predatory fish in OHTs is not feasible. The use of expanded polystyrene (EPS) beads is a potential alternative in these habitats. EPS beads not only prevent oviposition but also kill the immature by forming a thick blanket on the water surface. A thick layer of 2 cm with beads of 2 mm is sufficient to suppress and prevent mosquito breeding. These are cheap, environmentally safe and do not need frequent application since they remain on the surface for quiet a long time. Successful trials against C. quinquefasciatus breeding in pit latrines, soakage pits, septic tanks, etc., have been carried out in Kenya, Zimbabwe and Tanzania. Certain trials with EPS indicated reduction in microfilaria (mf) rate besides decline in biting density. In India, EPS beads have also been used on small scale for the control of A. stephensi and A. culicifacies breeding in OHTs and unused wells respectively. The polystyrene beads have also been reported to be effective in the control of mosquito breeding in biogas plants and other industrial situations. The practical utility of EPS beads in the control of vector-borne diseases has been discussed in the present review.

  16. Nanohole 3D-size tailoring through polystyrene bead combustion during thin film deposition

    International Nuclear Information System (INIS)

    Peng Xiaofeng; Kamiya, Itaru

    2009-01-01

    A novel approach is presented for nanohole 3D-size tailoring. The process starts with a monolayer of polystyrene (PS) beads spun coat on silicon wafer as a template. The holes can be directly prepared through combustion of PS beads by oxygen plasma during metal or oxide thin film deposition. The incoming particles are prevented from adhering on PS beads by H 2 O and CO 2 generated from the combustion of the PS beads. The hole depth generally depends on the film thickness. The hole diameter can be tailored by the PS bead size, film deposition rate, and also the combustion speed of the PS beads. In this work, a series of holes with depth of 4-24 nm and diameter of 10-36 nm has been successfully prepared. The hole wall materials can be selected from metals such as Au or Pt and oxides such as SiO 2 or Al 2 O 3 . These templates could be suitable for the preparation and characterization of novel nanodevices based on single quantum dots or single molecules, and could be extended to the studies of a wide range of coating materials and substrates with controlled hole depth and diameters.

  17. Adsorption of ochratoxin A from grape juice by yeast cells immobilised in calcium alginate beads.

    Science.gov (United States)

    Farbo, Maria Grazia; Urgeghe, Pietro Paolo; Fiori, Stefano; Marceddu, Salvatore; Jaoua, Samir; Migheli, Quirico

    2016-01-18

    Grape juice can be easily contaminated with ochratoxin A (OTA), one of the known mycotoxins with the greatest public health significance. Among the different approaches to decontaminate juice from this mycotoxin, microbiological methods proved efficient, inexpensive and safe, particularly the use of yeast or yeast products. To ascertain whether immobilisation of the yeast biomass would lead to successful decontamination, alginate beads encapsulating Candida intermedia yeast cells were used in our experiments to evaluate their OTA-biosorption efficacy. Magnetic calcium alginate beads were also prepared by adding magnetite in the formulation to allow fast removal from the aqueous solution with a magnet. Calcium alginate beads were added to commercial grape juice spiked with 20 μg/kg OTA and after 48 h of incubation a significant reduction (>80%), of the total OTA content was achieved, while in the subsequent phases (72-120 h) OTA was slowly released into the grape juice by alginate beads. Biosorption properties of alginate-yeast beads were tested in a prototype bioreactor consisting in a glass chromatography column packed with beads, where juice amended with OTA was slowly flowed downstream. The adoption of an interconnected scaled-up bioreactor as an efficient and safe tool to remove traces of OTA from liquid matrices is discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Preservation of viability and antibacterial activity of Lactobacillus spp. in calcium alginate beads.

    Science.gov (United States)

    Brachkova, Mariya I; Duarte, Maria A; Pinto, João F

    2010-12-23

    The objective of the study was to produce calcium alginate beads able to deliver Lactobacillus spp. (Lactobacillus plantarum, Lactobacillus rhamnosus GG, Lactobacillus bulgaricus and Lactobacillus lactis) with preserved viability and antibacterial activity. Four types of beads, containing entrapped (E), surface and entrapped (ES), surface (S) and concentrated surface and entrapped lactobacilli (C(ES)) were prepared and physically characterized. The antibacterial activity of lactobacilli cultures before and after immobilization, freeze-drying and throughout storage was studied in relationship to the viable number of lactobacilli. Multi-resistant clinical isolates (methicillin-resistant Staphylococcus aureus, vancomycine-resistant Enterococcus faecalis, VIM-2-metalo-β-lactamase producing Pseudomonas aeruginosa and CTX-M-15-β-lactamase producing strains: Escherichia coli and Klebsiella pneumoniae) were used as indicator strains. Alginate beads in which lactobacilli proliferated to the beads surface (ES and C(ES)) differed significantly from the other types of beads in their physicochemical properties, showing smoother surface morphology, more spherical shape, bigger weight, lower calcium content, density and crushing force. Lactobacilli cultures, at high cell concentrations (10(8)cfu/ml) were active against both Gram-positive and negative multi-resistant bacteria. Beads containing both entrapped and surface lactobacilli (ES) resulted in viability and antibacterial activity most similar to non-processed lactobacilli cultures. The viability and antibacterial activity of the immobilized lactobacilli remained stable after 6 months storage. Copyright © 2010 Elsevier B.V. All rights reserved.

  19. Optimization of Enzyme Co-Immobilization with Sodium Alginate and Glutaraldehyde-Activated Chitosan Beads.

    Science.gov (United States)

    Gür, Sinem Diken; İdil, Neslihan; Aksöz, Nilüfer

    2018-02-01

    In this study, two different materials-alginate and glutaraldehyde-activated chitosan beads-were used for the co-immobilization of α-amylase, protease, and pectinase. Firstly, optimization of multienzyme immobilization with Na alginate beads was carried out. Optimum Na alginate and CaCl 2 concentration were found to be 2.5% and 0.1 M, respectively, and optimal enzyme loading ratio was determined as 2:1:0.02 for pectinase, protease, and α-amylase, respectively. Next, the immobilization of multiple enzymes on glutaraldehyde-activated chitosan beads was optimized (3% chitosan concentration, 0.25% glutaraldehyde with 3 h of activation and 3 h of coupling time). While co-immobilization was successfully performed with both materials, the specific activities of enzymes were found to be higher for the enzymes co-immobilized with glutaraldehyde-activated chitosan beads. In this process, glutaraldehyde was acting as a spacer arm. SEM and FTIR were used for the characterization of activated chitosan beads. Moreover, pectinase and α-amylase enzymes immobilized with chitosan beads were also found to have higher activity than their free forms. Three different enzymes were co-immobilized with these two materials for the first time in this study.

  20. Development of bead-type radiophotoluminescence glass dosimeter applicable to various purposes

    International Nuclear Information System (INIS)

    Sato, F.; Toyota, Y.; Maki, D.; Zushi, N.; Kato, Y.; Yamamoto, T.; Iida, T.

    2013-01-01

    Bead-type radiophotoluminescence (RPL) glass dosimeters were well fabricated with a gas-particle jet flame system for glass melting-cooling process. A rod of silver-activated phosphate glass was pulverized into micrometer-size particles. Spherical glass particles were formed from the pulverized glass particles in the high-temperature jet flame owing to the surface tension of the glass material. Some groups of spherical glass particles were irradiated with X-rays and their RPL was demonstrably observed for their exposure to UV light. A flexible RPL glass sheet was also made of bead-type RPL glass dosimeters and was useful for radiation imaging. Bead-type RPL glass dosimeters are expected to be used for dose monitoring in highly radioactively-contaminated area. -- Highlights: ► We developed bead-type radiophotoluminescence glass dosimeters. ► Bead-type glass RPL dosimeters are satisfactorily used as radiation dosimeters. ► A flexible RPL glass sheet is made of bead-type RPL glass dosimeters

  1. Magnetic Bead Based Immunoassay for Autonomous Detection of Toxins

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Y; Hara, C A; Knize, M G; Hwang, M H; Venkatesteswaran, K S; Wheeler, E K; Bell, P M; Renzi, R F; Fruetel, J A; Bailey, C G

    2008-05-01

    As a step towards toward the development of a rapid, reliable analyzer for bioagents in the environment, we are developing an automated system for the simultaneous detection of a group of select agents and toxins. To detect toxins, we modified and automated an antibody-based approach previously developed for manual medical diagnostics that uses fluorescent eTag{trademark} reporter molecules and is suitable for highly multiplexed assays. Detection is based on two antibodies binding simultaneously to a single antigen, one of which is labeled with biotin while the other is conjugated to a fluorescent eTag{trademark} through a cleavable linkage. Aqueous samples are incubated with the mixture of antibodies along with streptavidin-coated magnetic beads coupled to a photo-activatable porphyrin complex. In the presence of antigen, a molecular complex is formed where the cleavable linkage is held in proximity to the photoactivable group. Upon excitation at 680 nm, free radicals are generated, which diffuse and cleave the linkage, releasing the eTags{trademark}. Released eTags{trademark} are analyzed using capillary gel electrophoresis with laser-induced fluorescence detection. Limits of detection for ovalbumin and botulinum toxoid individually were 4 ng/mL (or 80 pg) and 16 ng/mL (or 320 pg), respectively, using the manual assay. In addition, we demonstrated the use of pairs of antibodies from different sources in a single assay to decrease the rate of false positives. Automation of the assay was demonstrated on a flow-through format with higher LODs of 125 ng/mL (or 2.5 ng) each of a mixture of ovalbumin and botulinum toxoid. This versatile assay can be easily modified with the appropriate antibodies to detect a wide range of toxins and other proteins.

  2. Neutron activation analysis of sixteenth- and seventeenth-century European blue glass trade beads from the eastern Great Lakes area of North America

    International Nuclear Information System (INIS)

    Hancock, R.G.V.; Chafe, A.; Kenyon, I.

    1994-01-01

    Sixteenth- and seventeenth-century European blue glass trade beads from aboriginal sites in the eastern Great Lakes area of North America have been analysed non-destructively using low neutron dose instrumental neutron activation analysis, so that the beads could be returned to their keepers. Dark blue (cobalt-coloured) beads are readily separable from turquoise (copper-coloured) beads. Differences in the chemistries of the turquoise blue beads appear to be useful in separating glass beads from the two centuries. Low calcium, sixteenth-century turquoise beads tend to disintegrate by a leaching of the alkali metals. (Author)

  3. Shape memory polymers

    Science.gov (United States)

    Wilson, Thomas S.; Bearinger, Jane P.

    2015-06-09

    New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxyl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

  4. Tamarind seed gum-hydrolyzed polymethacrylamide-g-gellan beads for extended release of diclofenac sodium using 32full factorial design.

    Science.gov (United States)

    Nandi, Gouranga; Nandi, Amit Kumar; Khan, Najim Sarif; Pal, Souvik; Dey, Sibasish

    2018-03-19

    Development of tamarind seed gum (TSG)-hydrolyzed polymethacrylamide-g-gellan (h-Pmaa-g-GG) composite beads for extended release of diclofenac sodium using 3 2 full factorial design is the main purpose of this study. The ratio of h-Pmaa-g-GG and TSG and concentration of cross-linker CaCl 2 were taken as independent factors with three different levels of each. Effects of polymer ratio and CaCl 2 on drug entrapment efficiency (DEE), drug release, bead size and swelling were investigated. Responses such as DEE and different drug release parameters were statistically analyzed by 3 2 full factorial design using Design-Expert software and finally the formulation factors were optimized to obtain USP-reference release profile. Drug release rate was found to decrease with decrease in the ratio of h-Pmaa-g-GG:TSG and increase in the concentration of Ca 2+ ions in cross-linking medium. The optimized formulation showed DEE of 93.25% and an extended drug release profile over a period of 10h with f 2 =80.13. Kinetic modeling unveiled case-I-Fickian diffusion based drug release mechanism. Copyright © 2018 Elsevier B.V. All rights reserved.

  5. Effect of cross-linked biodegradable polymers on sustained release of sodium diclofenac-loaded microspheres

    Directory of Open Access Journals (Sweden)

    Avik Kumar Saha

    2013-12-01

    Full Text Available The objective of this study was to formulate an oral sustained release delivery system of sodium diclofenac(DS based on sodium alginate (SA as a hydrophilic carrier in combination with chitosan (CH and sodium carboxymethyl cellulose (SCMC as drug release modifiers to overcome the drug-related adverse effects and to improve bioavailability. Microspheres of DS were prepared using an easy method of ionotropic gelation. The prepared beads were evaluated for mean particle size, entrapment efficiency, swelling capacity, erosion and in-vitro drug release. They were also subjected to various studies such as Fourier Transform Infra-Red Spectroscopy (FTIR for drug polymer compatibility, Scanning Electron Microscopy for surface morphology, X-ray Powder Diffraction Analysis (XRD and Differential Scanning Calorimetric Analysis (DSC to determine the physical state of the drug in the beads. The addition of SCMC during the preparation of polymeric beads resulted in lower drug loading and prolonged release of the DS. The release profile of batches F5 and F6 showed a maximum drug release of 96.97 ± 0.356% after 8 h, in which drug polymer ratio was decreased. The microspheres of sodium diclofenac with the polymers were formulated successfully. Analysis of the release profiles showed that the data corresponds to the diffusion-controlled mechanism as suggested by Higuchi.

  6. Deuterium exchange in sesamol

    International Nuclear Information System (INIS)

    Hill, R.K.; Vaidya, N.A.; Morton, G.H.

    1982-01-01

    Trifluoroacetic acid-catalyzed exchange of sesamol in 2 H 2 O results in rapid exchange of H-6 and slower exchange of H-2. The deuterium atoms introduced are retained during conversion to the methyl and allyl ethers. (author)

  7. Theoretical study of in-plane response of magnetic field sensor to magnetic beads in an in-plane homogeneous field

    DEFF Research Database (Denmark)

    Damsgaard, Christian Danvad; Hansen, Mikkel Fougt

    2008-01-01

    We present a systematic theoretical study of the average in-plane magnetic field on square and rectangular magnetic field sensors from a single magnetic bead and a monolayer of magnetic beads magnetized by an in-plane externally applied homogeneous magnetic field. General theoretical expressions...... are derived such that the sensor response and its dependence on the sensor size, spacer layer thickness, bead diameter, and bead susceptibility can easily be evaluated. The average magnetic field from a single bead close to the sensor shows a strong dependence on the position of the bead and a change of sign...... when the bead passes the edge of the sensor in the direction of the applied field. Analytical approximations are derived for the average field from a homogeneous monolayer of beads for beads much smaller than the sensor dimension and for a bead size chosen to minimize the position sensitivity...

  8. Effect of solvent/disinfectant ethanol on the micro-surface structure and properties of multiphase denture base polymers.

    Science.gov (United States)

    Basavarajappa, Santhosh; Al-Kheraif, Abdul Aziz Abdullah; ElSharawy, Mohamed; Vallittu, Pekka K

    2016-02-01

    The aim of this study was to evaluate the effect of solvent/disinfectant ethanol on the surface of denture base polymers. Changes in surface roughness, topography and some nanomechanical properties were assessed by SEM and nanoindentation plotted against different concentrations of ethanol on heat cured and autopolymerized polymetyl methacrylate based acrylic denture base polymers. Test specimens (10×10×3mm(3)) of heat-curing (HC) and auto-polymerizing (AP) acrylic resin were prepared and polished to obtain uniform smoothness which were further grouped into 3 sub-groups HC1, HC2, HC3 and AP1, AP2, AP3 respectively 10 specimens (n) in each group. HC1 and AP1, HC2 and AP2, HC3 and AP3 were treated with 99.9%, 70% and 40% respectively for 30, 60 and 120s followed by analysis of surface roughness (Sa), topographical changes and some nanomechanical properties. Both HC and AP resins showed changes in their Sa and nanomechanically measured modulus of elasticity and surface hardness after being treated at different concentrations of ethanol and at different lengths of time. Surface changes were most clearly seen in autopolymerizing denture base polymer, especially at the interface region between the PMMA polymer bead and polymer matrix. There was a correlation (R2=0.83, r=0.91, Pdisinfectant ethanol. The interphase region between the PMMA polymer bead and the polymer matrix was most affected by the ethanol. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Totalization Data Exchange (TDEX)

    Data.gov (United States)

    Social Security Administration — The Totalization Data Exchange (TDEX) process is an exchange between SSA and its foreign country partners to identify deaths of beneficiaries residing abroad. The...

  10. Evaluation of passive samplers with neutral or ion-exchange polymer coatings to determine freely dissolved concentrations of the basic surfactant lauryl diethanolamine: Measurements of acid dissociation constant and organic carbon-water sorption coefficient.

    Science.gov (United States)

    Wang, Fang; Chen, Yi; Hermens, Joop L M; Droge, Steven T J

    2013-11-08

    A passive sampler tool (solid-phase microextraction, SPME) was optimized to measure freely dissolved concentrations (Cw,free) of lauryl diethanolamine (C12-DEA). C12-DEA can be protonated and act as a cationic surfactant. From the pH-dependent sorption to neutral SPME coatings (polyacrylate and PDMS), a pKa of 8.7 was calculated, which differs more than two units from the value of 6.4 reported elsewhere. Polyacrylate coated SPME could not adequately sample largely protonated C12-DEA in humic acid solutions of pH 6. A new hydrophobic SPME coating with cation-exchange properties (C18/SCX) sorbed C12-DEA 100 fold stronger than polyacrylate, because it specifically sorbs protonated C12-DEA species. The C18/SCX-SPME fiber showed linear calibration isotherms in a concentration range of acid at pH 6 (ionic strength 0.015 M) were measured over a broad concentration range with a sorption coefficient of 10(5.3). Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Polymer nanocomposites: polymer and particle dynamics

    KAUST Repository

    Kim, Daniel

    2012-01-01

    Polymer nanocomposites containing nanoparticles smaller than the random coil size of their host polymer chains are known to exhibit unique properties, such as lower viscosity and glass transition temperature relative to the neat polymer melt. It has been hypothesized that these unusual properties result from fast diffusion of the nanostructures in the host polymer, which facilitates polymer chain relaxation by constraint release and other processes. In this study, the effects of addition of sterically stabilized inorganic nanoparticles to entangled cis-1,4-polyisoprene and polydimethylsiloxane on the overall rheology of nanocomposites are discussed. In addition, insights about the relaxation of the host polymer chains and transport properties of nanoparticles in entangled polymer nanocomposites are presented. The nanoparticles are found to act as effective plasticizers for their entangled linear hosts, and below a critical, chemistry and molecular-weight dependent particle volume fraction, lead to reduced viscosity, glass transition temperature, number of entanglements, and polymer relaxation time. We also find that the particle motions in the polymer host are hyperdiffusive and at the nanoparticle length scale, the polymer host acts like a simple, ideal fluid and the composites\\' viscosity rises with increasing particle concentration. © 2012 The Royal Society of Chemistry.

  12. Ion exchange fiber by radiation grafting, 1

    International Nuclear Information System (INIS)

    Fujiwara, Kunio

    1990-01-01

    Radiation grafting is gaining attention as a method for producing high performance materials. This method can be applied to add functions to existing polymer plastics. The author participated in the research program on the production of ion exchange fiber by radiation grafting and its applicability at the Japan Atomic Energy Research Institute, Takasaki Radiation Chemistry Research Establishment. Consequently, it was clarified that it was possible to introduce the cation exchange group, represented by sulfonic and carboxyl groups, and the anion exchange group, represented by the quarternary ammonium group, to polypropylene fiber available on the market. The ion exchange capacity was able to be controlled by the degree of grafting, i.e. approximately up to 3 meq/g in both strong acid and strong base and approximately up to 5 meq/g in weak acid were obtained. The adsorption performance of ammonia, a representative malodorous substance, was also studied using test cation exchange fiber. The adsorption rate of H type strong acid cation exchange fiber was great, due to the H type having neutral reaction, and the adsorption capacity matched the ion exchange capacity. Although the Cu and Ni types features coordinated adsorption and their adsorption rates were from 1/2 to 1/3 of that of the H type, their adsorption capacities showed increase along with the metal adsorbed. (author)

  13. Magnetic chitosan/clay beads: A magsorbent for the removal of cationic dye from water

    Energy Technology Data Exchange (ETDEWEB)

    Bée, Agnès, E-mail: agnes.bee@upmc.fr [Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire PHENIX, F-75005 Paris (France); Obeid, Layaly, E-mail: lghannoum@hotmail.fr [Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire PHENIX, F-75005 Paris (France); CertiNergy Solutions, 33 avenue du Maine, BP 195, 75755 Paris Cedex 15 (France); Mbolantenaina, Rakotomalala, E-mail: mbolantenaina@yahoo.fr [Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire PHENIX, F-75005 Paris (France); Welschbillig, Mathias, E-mail: welschbillig@certinergysolutions.com [CertiNergy Solutions, 33 avenue du Maine, BP 195, 75755 Paris Cedex 15 (France); Talbot, Delphine, E-mail: delphine.talbot@upmc.fr [Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire PHENIX, F-75005 Paris (France)

    2017-01-01

    A magnetic composite material composed of magnetic nanoparticles and clay encapsulated in cross-linked chitosan beads was prepared, characterized and used as a magsorbent for the removal of a cationic dye, methylene blue (MB), from aqueous solutions. The magnetic properties of these beads represent an advantage to recover them at the end of the depollution process. The optimal weight ratio R=clay:chitosan for the removal of MB in a large range of pH was determined. For beads without clay, the maximal adsorption capacity of MB occurs in the pH range [9–12], while for beads with clay, the pH range extends by increasing the amount of clay to reach [3–12] for R>0.5. Adsorption isotherms show that the adsorption capacity of magnetic beads is equal to 82 mg/g. Moreover, the kinetics of dye adsorption is relatively fast since 50% of the dye is removed in the first 13 min for an initial MB concentration equal to 100 mg/L. The estimation of the number of adsorption sites at a given pH shows that the main driving force for adsorption of MB in a large range of pH is the electrostatic interaction between the positively charged dye and the permanent negative charges of clay. - Highlights: • A magsorbent based on magnetic nanoparticles and clay encapsulated in chitosan beads was prepared and characterized. • Clay played significant role for the removal of a cationic dye. • The magnetic beads exhibit a maximum adsorption capacity of 82 mg/g for methylene blue. • The pH range of the maximum adsorption extends from [9–12] to [3–12] by increasing the amount of clay. • The magsorbent could be magnetically removed from solution.

  14. Self-Assembly of Emulsion Droplets into Polymer Chains

    Science.gov (United States)

    Bargteil, Dylan; McMullen, Angus; Brujic, Jasna

    We experimentally investigate `beads-on-a-string' models of polymers using the spontaneous assembly of emulsion droplets into linear chains. Droplets functionalized with surface-mobile DNA allow for programmable 'monomers' through which we can influence the three-dimensional structure of the assembled 'polymer'. Such model polymers can be used to study conformational changes of polypeptides and the principles governing protein folding. In our system, we find that droplets bind via complementary DNA strands that are recruited into adhesion patches. Recruitment is driven by the DNA hybridization energy, and is limited by the energy cost of surface deformation and the entropy loss of the mobile linkers, yielding adhesion patches of a characteristic size with a given number of linkers. By tuning the initial surface coverage of linkers, we control valency between the droplets to create linear or branched polymer chains. We additionally control the flexibility of the model polymers by varying the salt concentration and study their dynamics between extended and collapsed states. This system opens the possibility of programming stable three-dimensional structures, such as those found within folded proteins.

  15. Origin of spatial organization of DNA-polymer in bacterial chromosomes

    Science.gov (United States)

    Agarwal, Tejal; Manjunath, G. P.; Habib, Farhat; Chatterji, Apratim

    2018-01-01

    In vivo DNA organization at large length scales (∼100 \\text{nm}) is highly debated and polymer models have proved useful to understand the principles of DNA organization. Here, we show that extracted from contact maps of bacterial DNA. We are able to predict the structure of 2 DNAs (E. coli and Caulobacter crescentus) using Monte Carlo simulations of the bead-spring polymer with cross-links at these special positions. Simulations with cross-links at random positions along the chain show that the organization of the polymer is different in nature from the previous case. We provide some direct and some indirect experimental validation for our predicted organization of DNA-polymers.

  16. Resolving Properties of Polymers and Nanoparticle Assembly through Coarse-Grained Computational Studies.

    Energy Technology Data Exchange (ETDEWEB)

    Grest, Gary S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-09-01

    Coupled length and time scales determine the dynamic behavior of polymers and polymer nanocomposites and underlie their unique properties. To resolve the properties over large time and length scales it is imperative to develop coarse grained models which retain the atomistic specificity. Here we probe the degree of coarse graining required to simultaneously retain significant atomistic details a nd access large length and time scales. The degree of coarse graining in turn sets the minimum length scale instrumental in defining polymer properties and dynamics. Using polyethylene as a model system, we probe how the coarse - graining scale affects the measured dynamics with different number methylene group s per coarse - grained beads. Using these models we simulate polyethylene melts for times over 500 ms to study the viscoelastic properties of well - entangled polymer melts and large nanoparticle assembly as the nanoparticles are driven close enough to form nanostructures.

  17. Static and dynamic properties of grafted ring polymer: Molecular dynamics simulation

    Science.gov (United States)

    He, Su-Zhen; Holger, Merlitz; Su, Chan-Fei; Wu, Chen-Xu

    2013-01-01

    The static and dynamic properties of a system of end-grafted flexible ring polymer chains grafted to a flat substrate and exposed to a good solvent are studied by using a molecular dynamics method. The monomers are described by a coarse-grained bead-spring model. Varying the grafting density ρ and the degree of polymerization or chain length N, we obtain the density profiles of monomers, study the structural properties of the chain (radius of gyration, bond orientational parameters, etc.), and also present the dynamic characteristics such as chain energy and bond force. Compared with a linear polymer brush, the ring polymer brush exhibits different static and dynamic properties for moderate or short chain length, while it behaves like linear polymer brush in the regime of long chain length.

  18. DIVALENT ION EXCHANGE WITH ALKALI

    Energy Technology Data Exchange (ETDEWEB)

    Bunge, A.L.; Klein, G.; Radke, C.J.

    1980-05-01

    Exchange of hardness ions is important in enhanced oil recovery with chemical additives. In both micellar-polymer and caustic flooding processes, multivalent ions released from rock surfaces can interact with anionic surfactants, rendering them preferentially oil soluble and/or insoluble in water. Because hardness cations are sparingly soluble and precipitate in alkaline solutions, such solutions may be more efficient as surfactant flood preflushes than are softened brines. Multivalent ion precipitation may also occur in alkaline waterflooding. To permit design of such processes, this paper presents a chromatographic theory for simultaneous ion exchange with precipitation of divalent ions. Theoretical effluent histories and concentration profiles are presented for the cases of finite pulses and continuous injection of hydroxide ions into linear cores. Complete capture of the insoluble salt particles is assumed. Results are given for the case of instantaneous equilibration of the solution with the precipitate, as well for the case of complete nonequilibrium, in which the solid precipitate does not redissolve. The efficiency of alklaine preflushing is shown to depend on the exchange isotherm, initial divalent loading of the rock, injected pH and salinity, the solubility product of the precipitated salt, and pulse size. The effect of slug size on complete equilibrium removal of hardness ions is reduced efficiency with increasing size until a critical volume approximating continuous injection is reached. Increasing injected pH and salinity provides a more favorable response. Experimental data for Berea sandstone and an argillaceous sand compare favorably with the proposed theory.

  19. Antimicrobial Polymers with Metal Nanoparticles

    Directory of Open Access Journals (Sweden)

    Humberto Palza

    2015-01-01

    Full Text Available Metals, such as copper and silver, can be extremely toxic to bacteria at exceptionally low concentrations. Because of this biocidal activity, metals have been widely used as antimicrobial agents in a multitude of applications related with agriculture, healthcare, and the industry in general. Unlike other antimicrobial agents, metals are stable under conditions currently found in the industry allowing their use as additives. Today these metal based additives are found as: particles, ions absorbed/exchanged in different carriers, salts, hybrid structures, etc. One recent route to further extend the antimicrobial applications of these metals is by their incorporation as nanoparticles into polymer matrices. These polymer/metal nanocomposites can be prepared by several routes such as in situ synthesis of the nanoparticle within a hydrogel or direct addition of the metal nanofiller into a thermoplastic matrix. The objective of the present review is to show examples of polymer/metal composites designed to have antimicrobial activities, with a special focus on copper and silver metal nanoparticles and their mechanisms.

  20. PEE-PEO block copolymer exchange rate between micelles is detergent and temperature activated

    Science.gov (United States)

    Schantz, Allen; Saboe, Patrick; Lee, Hee-Young; Sines, Ian; Butler, Paul; Bishop, Kyle; Maranas, Janna; Kumar, Manish

    We examine the kinetics of polymer chain exchange between polymer/detergent micelles, a system relevant to the synthesis of protein-containing biomimetic membranes. Although chain exchange between polymer aggregates in water is too slow to observe, adding detergent allows us to determine chain exchange rates using time-resolved small-angle neutron scattering (TR-SANS). We examine a membrane-protein-relevant, vesicle-forming ultra-short polymer, Poly(ethyl ethylene)20-Poly(ethylene oxide)18 (PEE20-PEO18). PEE20-PEO18 is solubilized in mixed micelles with the membrane-protein-compatible non-ionic detergent octyl- β -D-glucoside (OG). We show that OG activates block copolymer exchange, and obtain rate constants at two detergent concentrations above the CMC (critical micellar concentration) of OG. We find that chain exchange increases two orders of magnitude when temperature increases from 308 to 338 K, and that even a 1 mg/mL increase in OG concentration leads to a noticeable increase in exchange rate. We also calculate the activation energy for chain exchange and find that it is much higher than for lipid exchange. These findings explain the need for high detergent concentration and/or temperature to synthesize densely packed polymer/protein membranes.

  1. Cation immobilization in pyrolyzed simulated spent ion exchange resins

    Energy Technology Data Exchange (ETDEWEB)

    Luca, Vittorio, E-mail: vluca@cnea.gov.ar [Programa Nacional de Gestion de Residuos Radiactivos, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Av. General, Paz 1499, 1650 San Martin, Provincia de Buenos Aires (Argentina); Bianchi, Hugo L. [Gerencia de Quimica, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Av. General, Paz 1499, 1650 San Martin, Provincia de Buenos Aires (Argentina); ECyT, Universidad Nacional de General San Martin, Campus Miguelete, Ed. Tornavias, Martin de Irigoyen 3100, 1650 San Martin (Argentina); Conicet, Av. Rivadavia 1917, 1033 Buenos Aires (Argentina); Manzini, Alberto C. [Programa Nacional de Gestion de Residuos Radiactivos, Comision Nacional de Energia Atomica, Av. Del Libertador 8250, CP 1429, Ciudad Autonoma de Buenos Aires (Argentina)

    2012-05-15

    Significant quantities of spent ion exchange resins that are contaminated by an assortment of radioactive elements are produced by the nuclear industry each year. The baseline technology for the conditioning of these spent resins is encapsulation in ordinary Portland cement which has various shortcomings none the least of which is the relatively low loading of resin in the cement and the poor immobilization of highly mobile elements such as cesium. The present study was conducted with cationic resin samples (Lewatit S100) loaded with Cs{sup +}, Sr{sup 2+}, Co{sup 2+}, Ni{sup 2+} in roughly equimolar proportions at levels at or below 30% of the total cation exchange capacity. Low temperature thermal treatment of the resins was conducted in inert (Ar), or reducing (CH{sub 4}) gas atmospheres, or supercritical ethanol to convert the hydrated polymeric resin beads into carbonaceous materials that contained no water. This pyrolytic treatment resulted in at least a 50% volume reduction to give mechanically robust spherical materials. Scanning electron microscope investigations of cross-sections of the beads combined with energy dispersive analysis showed that initially all elements were uniformly distributed through the resin matrix but that at higher temperatures the distribution of Cs became inhomogeneous. Although Cs was found in the entire cross-section, a significant proportion of the Cs occurred within internal rings while a proportion migrated toward the outer surfaces to form a crustal deposit. Leaching experiments conducted in water at 25 Degree-Sign C showed that the divalent contaminant elements were very difficult to leach from the beads heated in inert atmospheres in the range 200-600 Degree-Sign C. Cumulative fractional loses of the order of 0.001 were observed for these divalent elements for temperatures below 500 Degree-Sign C. Regardless of the processing temperature, the cumulative fractional loss of Cs in water at 25 Degree-Sign C reached a plateau or

  2. Cation immobilization in pyrolyzed simulated spent ion exchange resins

    International Nuclear Information System (INIS)

    Luca, Vittorio; Bianchi, Hugo L.; Manzini, Alberto C.

    2012-01-01

    Significant quantities of spent ion exchange resins that are contaminated by an assortment of radioactive elements are produced by the nuclear industry each year. The baseline technology for the conditioning of these spent resins is encapsulation in ordinary Portland cement which has various shortcomings none the least of which is the relatively low loading of resin in the cement and the poor immobilization of highly mobile elements such as cesium. The present study was conducted with cationic resin samples (Lewatit S100) loaded with Cs + , Sr 2+ , Co 2+ , Ni 2+ in roughly equimolar proportions at levels at or below 30% of the total cation exchange capacity. Low temperature thermal treatment of the resins was conducted in inert (Ar), or reducing (CH 4 ) gas atmospheres, or supercritical ethanol to convert the hydrated polymeric resin beads into carbonaceous materials that contained no water. This pyrolytic treatment resulted in at least a 50% volume reduction to give mechanically robust spherical materials. Scanning electron microscope investigations of cross-sections of the beads combined with energy dispersive analysis showed that initially all elements were uniformly distributed through the resin matrix but that at higher temperatures the distribution of Cs became inhomogeneous. Although Cs was found in the entire cross-section, a significant proportion of the Cs occurred within internal rings while a proportion migrated toward the outer surfaces to form a crustal deposit. Leaching experiments conducted in water at 25 °C showed that the divalent contaminant elements were very difficult to leach from the beads heated in inert atmospheres in the range 200–600 °C. Cumulative fractional loses of the order of 0.001 were observed for these divalent elements for temperatures below 500 °C. Regardless of the processing temperature, the cumulative fractional loss of Cs in water at 25 °C reached a plateau or steady-state within the first 24 h increasing only

  3. Distribution and biophysical processes of beaded streams in Arctic permafrost landscapes

    Science.gov (United States)

    Arp, Christopher D.; Whitman, Matthew S.; Jones, Benjamin M.; Grosse, Guido; Gaglioti, Benjamin V.; Heim, Kurt C.

    2015-01-01

    Beaded streams are widespread in permafrost regions and are considered a common thermokarst landform. However, little is known about their distribution, how and under what conditions they form, and how their intriguing morphology translates to ecosystem functions and habitat. Here we report on a Circum-Arctic survey of beaded streams and a watershed-scale analysis in northern Alaska using remote sensing and field studies. We mapped over 400 channel networks with beaded morphology throughout the continuous permafrost zone of northern Alaska, Canada, and Russia and found the highest abundance associated with medium- to high- ground ice content permafrost in moderately sloping terrain. In the Fish Creek watershed, beaded streams accounted for half of the drainage density, occurring primarily as low-order channels initiating from lakes and drained lake basins. Beaded streams predictably transition to alluvial channels with increasing drainage area and decreasing channel slope, although this transition is modified by local controls on water and sediment delivery. Comparison of one beaded channel using repeat photography between 1948 and 2013 indicate a relatively stable landform and 14C dating of basal sediments suggest channel formation may be as early as the Pleistocene-Holocene transition. Contemporary processes, such as deep snow accumulation in riparian zones effectively insulates channel ice and allows for perennial liquid water below most beaded stream pools. Because of this, mean annual temperatures in pool beds are greater than 2°C, leading to the development of perennial thaw bulbs or taliks underlying these thermokarst features. In the summer, some pools thermally stratify, which reduces permafrost thaw and maintains coldwater habitats. Snowmelt generated peak-flows decrease rapidly by two or more orders of magnitude to summer low flows with slow reach-scale velocity distributions ranging from 0.1 to 0.01 m/s, yet channel runs still move water rapidly

  4. Polymers and radiation

    International Nuclear Information System (INIS)

    Zagorski, Z.

    2000-01-01

    The article is the broad review of history and state of art in radiation chemistry of polymers. The scientific background of radiation interaction with polymers and mechanisms of radiolytic degradation for aqueous solutions and 'dry' state of polymers have been shown. Also the applications of radiation for polymer properties modifications has been discussed in terms of polymers grafting and cross-linking for achieve shape memory feature, preparation of radioresistant polymers used for medical supplies being devoted to radiation sterilization etc. The polish contribution in related studies has been presented as well

  5. Conducting polymer materials

    Directory of Open Access Journals (Sweden)

    Jovanović Slobodan M.

    2003-01-01

    Full Text Available Conducting polymers represent a very interesting group of polymer materials Investigation of the synthesis, structure and properties of these materials has been the subject of considerable research efforts in the last twenty years. A short presentating of newer results obtained by investigating of the synthesis, structure and properties of two basic groups of conducting polymers: a conducting polymers the conductivity of which is the result of their molecular structure, and b conducting polymer composites (EPC, is given in this paper. The applications and future development of this group of polymer materials is also discussed.

  6. Exchange market pressure

    NARCIS (Netherlands)

    Jager, H.; Klaassen, F.; Durlauf, S.N.; Blume, L.E.

    2010-01-01

    Currencies can be under severe pressure in the foreign exchange market, but in a fixed (or managed) exchange rate regime that is not fully visible via the change in the exchange rate. Exchange market pressure (EMP) is a concept developed to nevertheless measure the pressure in such cases. This

  7. Development of functional polymers by electron beam

    International Nuclear Information System (INIS)

    Okamoto, Jiro

    1992-01-01

    Radiation-induced grafting is known as a method for introducing functional groups in a variety of polymers and inorganic substances. Various radiation grafting methods have been extensively developed in the early years and these have been the basis for radiation grafting research and development since that time. These are the preirradiation, the mutual, and the peroxide methods. Most of these methods investigated have been to create active sites on a polymer backbone by irradiation and reacting these with monomer which can then propagate to form grafted side chains of different structure. In this paper, the radiation grafting methods will be described and discussed in some detail together with their advantages and disadvantages. A few typical examples will be discussed with reference to research and development of functional materials such as ion exchange membrane, pervaporation membrane, fibrous ion exchanger and fibrous chelating agent for metal ions. (author)

  8. Disintegration of Nannochloropsis sp. cells in an improved turbine bead mill.

    Science.gov (United States)

    Pan, Zhidong; Huang, Ying; Wang, Yanmin; Wu, Zhiwei

    2017-12-01

    The Nannochloropsis sp. cells in aqueous solution were disintegrated in an improved bead mill with turbine agitator. The disintegration rates of cell samples disrupted under various operating parameters (i.e., circumferential speed, bead size, disintegration time, and cell concentration) were analyzed. An experimental strategy to optimize the parameters affecting the cell disintegration process was proposed. The results show that Nannochloropsis sp. cells can be effectively disintegrated in the turbine stirred bead mill under the optimum condition (i.e., circumferential speed of 2.3m/s, concentration of 15vol.%, disintegration time of 40min and bead size of 0.3-0.4mm). The disintegration mechanism was discussed via the selection and breakage functions from population balance modelling. It is revealed that the impact and compression effects of stirring beads are more effective for the disruption of coarser fraction of cells, and the shear effect dominates the production of finer fractions of disintegrated cells. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Preparation and characterization of physically modified glass beads used as model carriers in dry powder inhalers.

    Science.gov (United States)

    Zellnitz, Sarah; Redlinger-Pohn, Jakob Dominik; Kappl, Michael; Schroettner, Hartmuth; Urbanetz, Nora Anne

    2013-04-15

    The aim of this work is the physical modification and characterization of the surface topography of glass beads used as model carriers in dry powder inhalers (DPIs). By surface modification the contact area between drug and carrier and thereby interparticle forces may be modified. Thus the performance of DPIs that relies on interparticle interactions may be improved. Glass beads were chosen as model carriers because various prospects of physical surface modification may be applied without affecting other factors also impacting interparticle interactions like particle size and shape. To generate rough surfaces glass beads were processed mechanically by friction and impaction in a ball mill with different grinding materials that were smaller and harder with respect to the glass beads. By varying the grinding time (4 h, 8 h) and by using different grinding media (tungsten carbide, quartz) surfaces with different shades of roughness were generated. Depending on the hardness of the grinding material and the grinding time the surface roughness was more or less pronounced. Surface roughness parameters and specific surface area were determined via several complementary techniques in order to get an enhanced understanding of the impact of the modifying procedure on the surface properties of the glass beads. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Appropriate welding conditions of temper bead weld repair for SQV2A pressure vessel steel

    International Nuclear Information System (INIS)

    Mizuno, R.; Matsuda, F.; Brziak, P.; Lomozik, M.

    2004-01-01

    Temper bead welding technique is one of the most important repair welding methods for large structures for which it is difficult to perform the specified post weld heat treatment. In this study, appropriate temper bead welding conditions to improve the characteristics of heat affected zone (HAZ) are studied using pressure vessel steel SQV2A corresponding to ASTM A533 Type B Class 1. Thermal/mechanical simulator is employed to give specimens welding thermal cycles from single to quadruple cycle. Charpy absorbed energy and hardness of simulated CGHAZ by first cycle were degraded as compared with base metal. Improvability of these degradations by subsequent cycles is discussed and appropriate temper bead thermal cycles are clarified. When the peak temperature lower than Ac1 and near Ac1 in the second thermal cycle is applied to CGAHZ by first thermal cycle, the characteristics of CGHAZ improve enough. When the other peak temperatures (that is, higher than Ac1) in the second thermal cycle are applied to the CGHAZ, third or more thermal cycle temper bead process should be applied to improve the properties. Appropriate weld condition ranges are selected based on the above results. The validity of the selected ranges is verified by the temper bead welding test. (orig.)

  11. Construction of microscale structures in enclosed microfluidic networks by using a magnetic beads based method.

    Science.gov (United States)

    Wang, Zhenyu; Zhang, Xiaojuan; Yang, Jun; Yang, Zhong; Wan, Xiaoping; Hu, Ning; Zheng, Xiaolin

    2013-08-20

    A large number of microscale structures have been used to elaborate flowing control or complex biological and chemical reaction on microfluidic chips. However, it is still inconvenient to fabricate microstructures with different heights (or depths) on the same substrate. These kinds of microstructures can be fabricated by using the photolithography and wet-etching method step by step, but involves time-consuming design and fabrication process, as well as complicated alignment of different masters. In addition, few existing methods can be used to perform fabrication within enclosed microfluidic networks. It is also difficult to change or remove existing microstructures within these networks. In this study, a magnetic-beads-based approach is presented to build microstructures in enclosed microfluidic networks. Electromagnetic field generated by microfabricated conducting wires (coils) is used to manipulate and trap magnetic beads on the bottom surface of a microchannel. These trapped beads are accumulated to form a microscale pile with desired shape, which can adjust liquid flow, dock cells, modify surface, and do some other things as those fabricated microstructures. Once the electromagnetic field is changed, trapped beads may form new shapes or be removed by a liquid flow. Besides being used in microfabrication, this magnetic-beads-based method can be used for novel microfluidic manipulation. It has been validated by forming microscale dam structure for cell docking and modified surface for cell patterning, as well as guiding the growth of neurons. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Am/Cm TTR testing - 3/8-inch glass beads evaluation in CIM5

    International Nuclear Information System (INIS)

    Witt, D. C.

    2000-01-01

    To facilitate the procurement and handling of the glass former for Am/Cm vitrification in the F-Canyon MPPF, 1/4 inch and 3/8 inch diameter glass beads were purchased from Corning for evaluation in the 5 inch Cylindrical Induction Melter (CIM5). Prior to evaluating the beads in the CIM5, tests were conducted in the Drain Tube Test Stand (DTTS) with 1/4 inch beads, 3/8 inch beads, and a 50/50 mixture to identify any process concerns. Results of the DTTS tests are summarized in Attachment 1. A somewhat larger volume expansion was experienced in all three DTTS runs as compared to a standard run using cullet. Further testing of the use of glass beads in the CIM5 was requested by the Design Authority as Task 1.02 of Technical Task Request 99-MNSS/SE-006. Since the Technical Task Plan was not yet approved, the completion of this task was conducted under an authorization request approved by the SRTC Laboratory Director, S. Wood. This request is included as Attachment 2

  13. Adsorption of Cu2+ from aqueous solution onto modified glass beads with 3-aminopropyltriethoxysilane

    Directory of Open Access Journals (Sweden)

    Z Torkshavand

    2014-08-01

    Full Text Available The discharge of heavy metals into the aquatic ecosystem is a main concern over the last few decades. These pollutants are introduced into aquatic systems as a result of various industrial operations. This study investigates the efficiency of the modified glass beads with APTES ligand for removal of Cu2+ from the aqueous solution. Response surface methodology based on Box-Behnken was used to assess the effect of independent variables, including flow rate, solution pH, initial concentration and glass beads size on the response function and prediction of the best response value. Atomic absorption spectroscopic analysis of eluents of a column of the modified glass beads showed that Cu2+ ion was more than 90% entrapped on a column of glass beads. The isotherm evaluations indicate that the equilibrium data for Cu2+ adsorption could be fitted with the Langmuir model. Experimental data were also evaluated in terms of adsorption kinetics using the pseudo-first-order and pseudo-second-order kinetic models. The results also showed that the adsorption process of the Cu2+ well suited with the pseudo-second-order kinetics model. All the results demonstrated that modified glass beads successfully absorbed heavy metals from aqueous solution.

  14. Use of sterile pre-fabricated antibiotic beads in the combat hospital setting.

    Science.gov (United States)

    Gordon, Wade T; Petrides, Michael G; Gunn, Philip A; Howard, Michael

    2013-03-01

    Time and manpower constraints associated with acute combat casualty care can make antibiotic bead production at the point of care prohibitively difficult, if not impossible. The purpose of this study is to evaluate our technique for the sterile prefabrication of antibiotic-impregnated polymethylmethacrylate (PMMA) beads in the combat hospital environment by assessing their sterility at the time of use. This investigation is a prospective study of a consecutive series of specimens. Imipenem-impregnated antibiotic beads were sterilely prepared, threaded on a suture strand, and packaged. Over a 6-week period, 50 consecutive packages were evaluated for sterility with aerobic and anaerobic culture swabs performed at the time of opening. Culture results, as well as number of shelf days for each specimen, were then reviewed. Of the 50 packages of antibiotic-impregnated PMMA beads, the average number of days on the shelf before use was 9.3 (range: 2-17). None of the packages showed growth of organisms from the cultures, indicating that antibiotic-impregnated PMMA beads can be sterilely produced and maintained in their sterile state for future use in the combat hospital environment. This practice should be considered a safe adjunct in the management of contaminated, open traumatic injuries in this setting. Reprint & Copyright © 2013 Association of Military Surgeons of the U.S.

  15. Magnetic chitosan/clay beads: A magsorbent for the removal of cationic dye from water

    Science.gov (United States)

    Bée, Agnès; Obeid, Layaly; Mbolantenaina, Rakotomalala; Welschbillig, Mathias; Talbot, Delphine

    2017-01-01

    A magnetic composite material composed of magnetic nanoparticles and clay encapsulated in cross-linked chitosan beads was prepared, characterized and used as a magsorbent for the removal of a cationic dye, methylene blue (MB), from aqueous solutions. The magnetic properties of these beads represent an advantage to recover them at the end of the depollution process. The optimal weight ratio R=clay:chitosan for the removal of MB in a large range of pH was determined. For beads without clay, the maximal adsorption capacity of MB occurs in the pH range [9-12], while for beads with clay, the pH range extends by increasing the amount of clay to reach [3-12] for R>0.5. Adsorption isotherms show that the adsorption capacity of magnetic beads is equal to 82 mg/g. Moreover, the kinetics of dye adsorption is relatively fast since 50% of the dye is removed in the first 13 min for an initial MB concentration equal to 100 mg/L. The estimation of the number of adsorption sites at a given pH shows that the main driving force for adsorption of MB in a large range of pH is the electrostatic interaction between the positively charged dye and the permanent negative charges of clay.

  16. Enhancing the ecological validity of the Beads Task as a behavioral measure of intolerance of uncertainty.

    Science.gov (United States)

    Jacoby, Ryan J; Abramowitz, Jonathan S; Reuman, Lillian; Blakey, Shannon M

    2016-06-01

    To broaden the measurement of intolerance of uncertainty (IU) beyond self-report methods, recent research has examined the Beads Task as a behavioral measure of IU. In the present study, we enhanced this task to increase its ecological validity by maximizing decisional uncertainty and the importance of a correct response. Undergraduate participants (n=102) completed the Beads Task with instructions that they would complete the Cold Pressor Task (CPT) if they answered incorrectly. As hypothesized, baseline CPT endurance time and self-reported pain level were weakly associated with later Beads Task distress during the decision-making process. Furthermore, in vivo Beads Task distress was associated with self-report inhibitory IU, which measures avoidance and paralysis in the face of uncertainty, but not with prospective IU, perfectionism, or general psychological distress after making statistical adjustments for multiple comparisons. Comparisons to previous work using the Beads Task, clinical implications, and avenues for future research are discussed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. The characterization of ceramic alumina prepared by using additive glass beads

    Science.gov (United States)

    Suprapedi; Muljadi; Sardjono, Priyo

    2018-01-01

    The ceramic alumina has been made by using additive glass bead (5 and 10 % wt.). There are two kinds of materials, such as : gamma Alumina and glass bead. Synthesis of alumina was done by ball milling for 24 hours, then the mixed powder was dried in drying oven at 100 °C for 6 hours. Furthermore, the dried powder was mixed by using 2 % of PVA and continued with compacted to form a pellet with pressure of 50 MPA. The next step is sintering process with variation temperature of 1150, 1200, 1250, 1300 and 1400 °C and holding time for 2 hours. The characterization conducted are consist of test density, hardness, shrinkage, and microstructure. The results show that ceramic alumina with addition of 10 % wt. glass bead has the higher value of density, hardness and shrinkage than addition of 5% wt. glass bead. The highest characterization of ceramic alumina with addition 10 % glass bead was achieved at sintering temperature of 1400 °C with density 3.68 g/cm3, hardness vickers 780.40 Hv and shrinkage 15.23 %. The XRD results show that it was founds a corrundum (alpha Alumina) as dominant phase and mullite as minor phase.

  18. Encapsulation of thyme (Thymus serpyllum L.) aqueous extract in calcium alginate beads.

    Science.gov (United States)

    Stojanovic, Radoslava; Belscak-Cvitanovic, Ana; Manojlovic, Verica; Komes, Drazenka; Nedovic, Viktor; Bugarski, Branko

    2012-02-01

    Encapsulation of Thymus serpyllum L. aqueous extract within calcium alginate beads was studied in order to produce dosage formulations containing polyphenolic compounds. Electrostatic extrusion was applied for encapsulation of thyme aqueous extract in alginate gel beads. In addition to hydrogel beads, heat-dried and freeze-dried forms of beads were examined. Encapsulation systems were examined and compared in order to choose the optimal one with respect to entrapment efficiency, preservation of antioxidant activity and thermal behaviour under heating conditions simulating the usual food processing. The beads obtained with approximately 2 mg g⁻¹ of gallic acid equivalents encapsulated in 0.015 g mL⁻¹ of alginate were spheres of a uniform size of about 730 µm. Encapsulation efficiency varied in the range 50-80% depending on the encapsulation method. Besides, the analysis reveals that the encapsulation process and the material used did not degrade the bioactive compounds, as the total antioxidant content remained unchanged. This was verified by Fourier transform infrared analysis, which proved the absence of chemical interactions between extracted compounds and alginate. Addition of a filler substance, such as sucrose and inulin, in the dried product reduced its collapse and roundness distortion during drying process. This study demonstrates the potential of using hydrogel material for encapsulation of plant poplyphenols to improve their functionality and stability in food products. Copyright © 2011 Society of Chemical Industry.

  19. Optical vortex beam transmission with different OAM in scattering beads and brain tissue media

    Science.gov (United States)

    Wang, W. B.; Shi, Lingyan; Lindwasser, Lukas; Marque, Paulo; Lavery, M. P. J.; Alfano, R. R.

    2016-03-01

    Light transmission of Laguerre Gaussian (LG) vortex beams with different orbital angular momentum (OAM) values (L) in scattering beads and mouse brain tissue media were experimentally investigated for the first time in comparison with Gaussian (G) beams. The LG beams with different OAM were generated using a spatial light modulator (SLM) in reflection mode. The scattering beads media consist of various sizes and concentrations of latex beads in water solutions. The transmissions of LG and G beams through scattering beads and brain tissue media were measured with different ratios of sample thicknesses (z) to scattering mean free path (ls) of the turbid media, z/ls. The results indicate that within the ballistic region where z/ls is small, the LG and G beams show no significant difference, while in the diffusive region where z/ls is higher, the vortex beams show higher transmission than G beams. In the diffusive region, the LG beams with higher L values show higher transmission than the beams with lower L values due to the eigen channels in the media. The transition points from the ballistic to diffusive regions for different scattering beads and brain tissue media were studied.

  20. Successful subretinal delivery and monitoring of MicroBeads in mice.

    Directory of Open Access Journals (Sweden)

    M Dominik Fischer

    Full Text Available To monitor viability of implanted genetically engineered and microencapsulated human stem cells (MicroBeads in the mouse eye, and to study the impact of the beads and/or xenogenic cells on retinal integrity.MicroBeads were implanted into the subretinal space of SV126 wild type mice using an ab externo approach. Viability of microencapsulated cells was monitored by noninvasive retinal imaging (Spectralis™ HRA+OCT. Retinal integrity was also assessed with retinal imaging and upon the end of the study by light and electron microscopy. The implanted GFP-marked cells encapsulated in subretinal MicroBeads remained viable over a period of up to 4 months. Retinal integrity and viability appeared unaltered apart from the focal damage due to the surgical implantation, GFAP upregulation, and opsin mistargeting in the immediate surrounding tissue.The accessibility for routine surgery and its immune privileged state make the eye an ideal target for release system implants for therapeutic substances, including neurotrophic and anti-angiogenic compounds or protein based biosimilars. Microencapsulated human stem cells (MicroBeads promise to overcome limitations inherent with single factor release systems, as they are able to produce physiologic combinations of bioactive compounds.

  1. Study of mechanical and physicochemical properties of cementated spent ion-exchange-resins

    International Nuclear Information System (INIS)

    Patek, P.

    1981-09-01

    As first part of a study on the possibilities, to immobilize spent ion exchange resins, for final disposal, the dependence of compressive strength from the composition of cement - resin mixtures was detected. Powdered resins, bead resins and ashes from the incinerator plant and several cement brands were examinated. As result an area was defined in the three-phase diagram of cement, resins and water, in which the following leach tests will be performed. (author)

  2. Selective extraction of plutonium from nitric acid medium by bifunctional polyethersulfone beads for quantification with thermal ionisation mass spectrometry

    International Nuclear Information System (INIS)

    Paul, Sumana; Aggarwal, S.K.; Pandey, A.K.

    2015-01-01

    Polyethersulfone (PES) magnetic beads were prepared by phase inversion technique. The beads were grafted with two monomers, viz. 2-hydroxyethylmethacrylate phosphoric acid (HEMP) and (3-acrylamidopropyl)trimethyl ammonium chloride (AMAC), by photo-induced free radical polymerization. Effect of different HNO 3 concentrations on the sorption profiles of Am(III) and Pu(IV) was studied using the grafted PES beads. The beads were found to extract plutonium quantitatively from high nitric acid medium (3-8 M). The effect of presence of competing actinide, e.g. U(VI), on the sorption of Pu(IV) was also studied. (author)

  3. Determining the unique refractive index properties of solid polystyrene aerosol using broadband Mie scattering from optically trapped beads.

    Science.gov (United States)

    Jones, Stephanie H; King, Martin D; Ward, Andrew D

    2013-12-21

    A method is described to measure the refractive index dispersion with wavelength of optically trapped solid particles in air. Knowledge of the refraction properties of solid particles is critical for the study of aerosol; both in the laboratory and in the atmosphere for climate studies. Single micron-sized polystyrene beads were optically trapped in air using a vertically aligned counter-propagating configuration of focussed laser beams. Each bead was illuminated using white light from a broadband light emitting diode (LED) and elastic scattering within the bead was collected onto a spectrograph. The resulting Mie spectra were analysed to accurately determine polystyrene bead radii to ±0.4 nm and values of the refractive index to ±0.0005 over a wavelength range of 480-700 nm. We demonstrate that optical trapping combined with elastic scattering can be used to both accurately size polystyrene beads suspended in air and determine their wavelength dependent refractive index. The refractive index dispersions are in close agreement with reported values for polystyrene beads in aqueous dispersion. Our results also demonstrate a variation in the refractive index of polystyrene, from bead to bead, in a commercial sample. The measured variation highlights that care must be taken when using polystyrene beads as a calibration aerosol.

  4. MALDI-TOF MS combined with magnetic beads for detecting serum protein biomarkers and establishment of boosting decision tree model for diagnosis of systemic lupus erythematosus.

    Science.gov (United States)

    Huang, Zhuochun; Shi, Yunying; Cai, Bei; Wang, Lanlan; Wu, Yongkang; Ying, Binwu; Qin, Li; Hu, Chaojun; Li, Yongzhe

    2009-06-01

    To discover novel potential biomarkers and establish a diagnostic pattern for SLE by using proteomic technology. Serum proteomic spectra were generated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) combined with weak cationic exchange magnetic beads. A training set of spectra, derived from analysing sera from 32 patients with SLE, 43 patients with other autoimmune diseases and 43 age- and sex-matched healthy volunteers, was used to train and develop a decision tree model with a machine learning algorithm called decision boosting. A blinded testing set, including 32 patients with SLE, 42 patients with other autoimmune diseases and 40 healthy people, was used to determine the accuracy of the model. The diagnostic pattern with a panel of four potential protein biomarkers of mass-to-charge (m/z) ratio 4070.09, 7770.45, 28 045.1 and 3376.02 could accurately recognize 25 of 32 patients with SLE, 36 of 42 patients with other autoimmune diseases and 36 of 40 healthy people. The preliminary data suggested a potential application of MALDI-TOF MS combined with magnetic beads as an effective technology to profile serum proteome, and with pattern analysis, a diagnostic model comprising four potential biomarkers was indicated to differentiate individuals with SLE from RA, SS, SSc and healthy controls rapidly and precisely.

  5. Dynamics of end-linked star-polymer structures.

    Science.gov (United States)

    Satmarel, C; von Ferber, C; Blumen, A

    2005-07-15

    In this work we focus on the dynamics of macromolecular networks formed by end-linking identical polymer stars. The resulting macromolecular network can then be viewed as consisting of spacers which connect branching points (the cores of the stars). We succeed in analyzing exactly, in the framework of the generalized Gaussian model, the eigenvalue spectrum of such networks. As applications we focus on several topologies, such as regular networks and dendrimers; furthermore, we compare the results to those found for regular hyperbranched structures. In so doing, we also consider situations in which the beads of the cores differ from the beads of the spacers. The analytical procedure which we use involves an exact real-space renormalization, which allows to relate the star network to a (much simpler) network, in which each star is reduced to its core. It turns out that the eigenvalue spectrum of the star-polymer structure consists of two parts: one follows in terms of polynomial equations from the relaxation spectrum of the corresponding renormalized structure, while the second part involves the motion of the spacer chains themselves. Finally, we show exemplarily the situation for copolymeric dendrimers, calculate their spectra, and from them their storage and the loss moduli.

  6. Organic resin anion exchangers for the treatment of radioactive wastes

    International Nuclear Information System (INIS)

    Dyer, A.; McGinnes, D.F.

    1988-07-01

    Organic anion exchange resins are evaluated for 99-TcO 4 - (pertechnate) removed from aqueous nuclear waste streams. Chemical, thermal and radiation stabilities were studied. Selected resins were examined in detail for their selectivities in the presence of I - , NO 3 - , SO 4 = , CO 3 = , Cl - and OH - . Ion exchange equilibria and kinetic mechanisms were determined. Preliminary investigations of cement encapsulation in polymer modified form were made and some leach studies carried out. (author)

  7. A Fully Developed Flow Thermofluid Model for Topology Optimization of 3D-Printed Air-Cooled Heat Exchangers

    DEFF Research Database (Denmark)

    Haertel, Jan Hendrik Klaas; Nellis, Gregory F.

    2017-01-01

    . The conductance of the heat exchanger is maximized for a prescribed pressure drop and prescribed air-side temperature change across the heat exchanger. Polymer with infilled thermally conducting metal filaments is considered as the heat exchanger material which allows cost effective additive manufacturing...

  8. Analysis of platinum content in biodegradable carboplatin-impregnated beads and retrospective assessment of tolerability for intralesional use of the beads in dogs following excision of subcutaneous sarcomas: 29 cases (2011-2014).

    Science.gov (United States)

    Hess, Theresa A; Drinkhouse, Macy E; Prey, Joshua D; Miller, Jonathan M; Fettig, Arthur A; Carberry, Carol A; Brenn, Stephen H; Bailey, Dennis B

    2018-02-15

    OBJECTIVE To evaluate platinum content in biodegradable carboplatin-impregnated beads and retrospectively assess tolerability and outcome data for dogs treated by intralesional placement of such beads following surgical excision of subcutaneous sarcomas. DESIGN Evaluation study and retrospective case series. SAMPLE 9 carboplatin-impregnated beads and 29 client-owned dogs. PROCEDURES Platinum content in 9 carboplatin-impregnated beads from 3 lots was measured by spectrophotometry, and calculated carboplatin content was compared with the labeled content. Medical records were searched to identify dogs with subcutaneous sarcomas for which treatment included placement of carboplatin-impregnated beads between 2011 and 2014. Signalment, tumor characteristics, surgical and histologic data, adverse events, and local recurrences were recorded. Associations between variables of interest and adverse events or local disease-free interval were analyzed. RESULTS In vitro analysis identified a mean ± SD platinum content of 5.38 ± 0.97 mg/bead. Calculated carboplatin content (10.24 ± 1.84 mg/bead) was significantly greater than the labeled amount (4.6 mg/bead). Bead weight and total platinum content differed significantly among lots, but platinum content per bead weight did not. Mild-to-moderate local adverse events were reported for 11 of 29 tumors; all resolved without additional surgery. No dogs had signs of systemic toxicosis. Overall local disease-free rates 1, 2, and 3 years after surgery were 70%, 70%, and 58%, respectively, as determined by Kaplan-Meier analysis. CONCLUSIONS AND CLINICAL RELEVANCE Carboplatin-impregnated beads were well tolerated; however, results of in vitro tests indicated that caution is needed because of manufacturing inconsistencies.

  9. SINGLE AND DOUBLE IMPRINTED POLYMER FOR SELECTIVE RECOGNITION OF Cd(II IONS IN AQUEOUS MEDIA

    Directory of Open Access Journals (Sweden)

    Ebru Birlik ÖZKÜTÜK

    2010-12-01

    Full Text Available In this paper, we have reported the synthesis of a new single and double-imprinted polymeric material for the separation of Cd(II ions in aqueous solutions. Chitosan has choosen as the Cd(II metal complexing big polymer for single and double imprinted polymers. In the synthesis of single imprinted polymer, Cd(II-complexed chitosan has crosslinked by epichlorohydrin. In the synthesis of double imprinted polymer, Cd(II-complexed chitosan was reacted with 3-mercaptopropyl-trimethoxysilane. Then, the polymeric beads have crosslinked with tetraethoxysilane (TEOS. The imprinted cadmium ions have removed from the polymeric matrix by 0.1M HNO3 (to prepare Cd(II templates. Optimum pH for rebinding of Cd(II on the single and double-imprinted polymers was 7.0. Equilibrium binding time and sorbent capacity have been found as 120 and 60 min, 342 and 172 mg g-1 for single and double imprinted polymers, respectively. In selectivity studies, it has been found that double imprinted results in increased affinity of the material toward Cd(II ion over other competitor metal ions with the same charge. The prepared single and double-imprinted polymers have repeatedly used and regenerated for thirty times without a significant decrease in polymer binding affinities.

  10. Introduction to Polymer Chemistry.

    Science.gov (United States)

    Harris, Frank W.

    1981-01-01

    Reviews the physical and chemical properties of polymers and the two major methods of polymer synthesis: addition (chain, chain-growth, or chain-reaction), and condensation (step-growth or step-reaction) polymerization. (JN)

  11. Antiviral Polymer Therapeutics

    DEFF Research Database (Denmark)

    Smith, Anton Allen Abbotsford

    2014-01-01

    polymerized in a controlled manner with carrier monomers of historically proven biocompatible polymers. The carrier polymers, the loading of ribavirin as well as the size of the polymer were varied systematically with the aid of an automated synthesis platform. These polymers were tested in a cellular assay...... of reversible-addition-fragmentation chain transfer polymerization, which not only controls the size of polymer, but also allows the introduction of a terminal amine on the polymer which can be used for further conjugation. This has allowed for not only fluorescent labeling of the polymer, but also protein......The field of drug delivery is in essence an exercise in engineered pharmacokinetics. Methods of doing so have been developed through the introduction of a vehicle carrying the drug, either by encapsulation or covalent attachment. The emergence of polymer therapeutics in anticancer therapy has...

  12. Polymer Fluid Dynamics.

    Science.gov (United States)

    Bird, R. Byron

    1980-01-01

    Problems in polymer fluid dynamics are described, including development of constitutive equations, rheometry, kinetic theory, flow visualization, heat transfer studies, flows with phase change, two-phase flow, polymer unit operations, and drag reduction. (JN)

  13. Proteomic profiling of nephrotic syndrome in serum using magnetic bead based sample fractionation & MALDI-TOF MS

    Science.gov (United States)

    Sui, Weiguo; Dai, Yong; Zhang, Yue; Chen, Jiejing; Liu, Huaying; Huang, He

    2012-01-01

    Background & objectives: At present, the diagnosis of nephrotic syndrome (NS) requires a renal biopsy which is an invasive procedure. We undertook this pilot study to develop an alternative method and potential new biomarkers for diagnosis, and validated a set of well-integrated tools called ClinProt to investigate serum petidome in NS patients. Methods: The fasting blood samples from 49 patients diagnosed with NS by renal biopsy, including 17 mesangial proliferative glomerulonephritis (MsPGN), 12 minimal change nephrotic syndrome (MCNS), 10 focal segmental glomerulosclerosis (FSGS) and 10 membranous nephropathy (MN), were collected and screened to describe their variability of the serum peptidome. The results in NS group were compared with those in 10 control healthy individuals. Specimens were purified with magnetic beads-based weak cation exchange chromatography and analyzed in a MALDI-TOF MS. Results: The results showed 43, 61, 45 and 19 differential peptide peaks in MsPGN, MCNS, MN and FSGS groups, respectively. A Genetic Algorithm was used to set up the classification models. Cross validation of healthy controls from MsPGN, MCNS, MN and FSGS was 96.18, 100, 98.53 and 94.12 per cent, respectively. The recognition capabilities were 100 per cent. Interpretation & conclusions: Our results showed that proteomic analysis of serum with MALDI-TOF MS is a fast and reproducible approach, which may give an early idea of the pathology of nephrotic syndrome. PMID:22561615

  14. Analysis of early medieval glass beads - Glass in the transition period

    Energy Technology Data Exchange (ETDEWEB)

    Smit, Ziga, E-mail: ziga.smit@ijs.si [Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, SI-1000 Ljubljana (Slovenia); Jozef Stefan Institute, Jamova 39, P.O.B. 3000, SI-1001 Ljubljana (Slovenia); Knific, Timotej [National Museum of Slovenia, Presernova 20, SI-1000 Ljubljana (Slovenia); Jezersek, David [Jozef Stefan Institute, Jamova 39, P.O.B. 3000, SI-1001 Ljubljana (Slovenia); Istenic, Janka [National Museum of Slovenia, Presernova 20, SI-1000 Ljubljana (Slovenia)

    2012-05-01

    Glass beads from graves excavated in Slovenia and dated archaeologically to the 7th-10th century AD were analysed by the combined PIXE-PIGE method. The results indicate two groups of glass; natron glass made in the Roman tradition and glass made with alkalis from the ash of halophytic plants, which gradually replaced natron glass after c. 800 AD. The alkalis used in the second group of glass seem to be in close relation to a variant of the Venetian white glass that appeared several centuries later. The origin of this glass may be traced to glass production in Mesopotamia and around the Aral Sea. All the mosaic beads with eye decoration, as well as most of the drawn-segmented and drawn-cut beads analysed, are of plant-ash glass, which confirms their supposed oriental origin.

  15. Drug Release Profile from Calcium-Induced Alginate-Phosphate Composite Gel Beads

    Directory of Open Access Journals (Sweden)

    Yoshifumi Murata

    2009-01-01

    Full Text Available Calcium-induced alginate-phosphate composite gel beads were prepared, and model drug release profiles were investigated in vitro. The formation of calcium phosphate in the alginate gel matrix was observed and did not affect the rheological properties of the hydrogel beads. X-ray diffraction patterns showed that the calcium phosphate does not exist in crystalline form in the matrix. The initial release amount and release rate of a water-soluble drug, diclofenac, from the alginate gel beads could be controlled by modifying the composition of the matrix with calcium phosphate. In contrast, the release profile was not affected by the modification for hydrocortisone, a drug only slightly soluble in water.

  16. Quantitative determination of glycine in aqueous solution using glutamate dehydrogenase-immobilized glyoxal agarose beads.

    Science.gov (United States)

    Keskin, Semra Yilmazer; Keskin, Can Serkan

    2014-01-01

    In this study, an enzymatic procedure for the determination of glycine (Gly) was developed by using a column containing immobilized glutamate dehydrogenase (GDH) on glyoxal agarose beads. Ammonia is produced from the enzymatic reactions between Gly and GDH with NAD(+) in phosphate buffer medium. The indophenol blue method was used for ammonia detection based on the spectrophotometric measurements of blue-colored product absorbing at 640 nm. The calibration graph is linear in the range of 0.1-10 mM of Gly concentrations. The effect of pH, temperature, and time interval was studied to find column stability, and also the interference effects of other amino acids was investigated. The interaction between GDH and glyoxal agarose beads was analyzed by Fourier transform infrared (FTIR) spectroscopy. The morphology of the immobilized and non-immobilized agarose beads were characterized by atomic force microscopy (AFM).

  17. Online measurement of bead geometry in GMAW-based additive manufacturing using passive vision

    International Nuclear Information System (INIS)

    Xiong, Jun; Zhang, Guangjun

    2013-01-01

    Additive manufacturing based on gas metal arc welding is an advanced technique for depositing fully dense components with low cost. Despite this fact, techniques to achieve accurate control and automation of the process have not yet been perfectly developed. The online measurement of the deposited bead geometry is a key problem for reliable control. In this work a passive vision-sensing system, comprising two cameras and composite filtering techniques, was proposed for real-time detection of the bead height and width through deposition of thin walls. The nozzle to the top surface distance was monitored for eliminating accumulated height errors during the multi-layer deposition process. Various image processing algorithms were applied and discussed for extracting feature parameters. A calibration procedure was presented for the monitoring system. Validation experiments confirmed the effectiveness of the online measurement system for bead geometry in layered additive manufacturing. (paper)

  18. Characterization of bead trajectories through the draft tube of a turbine physical model

    Energy Technology Data Exchange (ETDEWEB)

    Weiland, M. A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Mueller, R. P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Carlson, T. J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Deng, Z. D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McKinstry, C. A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2005-02-01

    The U.S. Army Corps of Engineers (USACE) makes extensive use of 1:25 scale Plexiglass models of hydroelectric turbines along the Columbia River to study turbine hydraulic performance and to identify potential hazards for fish passing through the turbines. Plastic beads are sent through the models and imaging has been done with laser Doppler velocimetry and high-speed videography to measure flow field variables and to study the probable paths of fish through the turbine units. Understanding has been limited by the lack of data showing actual bead trajectories in three dimensions (3-D) and the lack of quantified velocity, acceleration, and other kinematics describing the trajectories of beads as they pass through the physical models.

  19. Feasibility study of plutonium isotopic analysis of resin beads by nondestructive gamma-ray spectroscopy

    International Nuclear Information System (INIS)

    Li, T.K.

    1985-01-01

    We have initiated a feasibility study on the use of nondestructive low-energy gamma-ray spectroscopy for plutonium isotopic analysis on resin beads. Seven resin bead samples were measured, with each sample containing an average of 9 μg of plutonium; the isotopic compositions of the samples varied over a wide range. The gamma-ray spectroscopy results, obtained from 4-h counting-time measurements, were compared with mass spectrometry results. The average ratios of gamma-ray spectroscopy to mass spectrometry were 1.014 +- 0.025 for 238 Pu/ 239 Pu, 0.996 +- 0.018 for 240 Pu/ 239 Pu, and 0.980 +- 0.038 for 241 Pu/ 239 Pu. The rapid, automated, and accurate nondestructive isotopic analysis of resin beads may be very useful to process technicians and International Atomic Energy Agency inspectors. 3 refs., 1 fig., 3 tabs

  20. Randomised controlled trial of extraarticular gold bead implantation for treatment of knee osteoarthritis: a pilot study

    DEFF Research Database (Denmark)

    Nejrup, Kirsten; Olivarius, Niels de Fine; Jacobsen, Judith L.

    2008-01-01

    The primary objective of this double-blind, randomised, controlled trial was to determine if implanting gold beads at five acupuncture points around the knee joint improves 1-year outcomes for patients with osteoarthritis (OA) of the knee. Participants were 43 adults aged 18-80 years with pain...... and stiffness from non-specific OA of the knee for over a year. The intervention was blinded implantation of gold beads at five acupuncture points around the affected knee through a hypodermic needle, or needle insertion alone. Primary outcome measures were knee pain, stiffness and function assessed...... acupuncture had greater relative improvements in self-assessed outcomes. The treatment was well tolerated. This 1-year pilot study indicates that extraarticular gold bead implantation is a promising treatment modality for patients with OA of the knee. The new treatment should be tested in a larger trial...