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Sample records for ps-cats polymer beads

  1. Photoacoustic infrared spectroscopy of polymer beads.

    Science.gov (United States)

    Wen, Qing; Michaelian, Kirk H

    2009-09-01

    Photoacoustic (PA) spectra of four types of polymer resin beads, ranging in size from 35 to 150 microm, were acquired using a Fourier transform infrared spectrometer capable of both rapid- and step-scan mirror movement. Thermal diffusion lengths were on the order of the particle sizes of the beads. The PA magnitude spectra were similar to absorption spectra; both positive- and negative-going features occurred in the phase spectra. The frequency dependences of the total PA intensities of the polymer resins and carbon black differed by a factor of about f(-0.30). The intensities of the weak bands in the ratioed spectra (resin beads/carbon black) displayed a similar dependence. Partial saturation caused a more gradual variation for the stronger bands, where the intensity is proportional to approximately f(-0.1)-f(-0.2).

  2. Polymer-Coated Graphene Aerogel Beads and Supercapacitor Application.

    Science.gov (United States)

    Ouyang, An; Cao, Anyuan; Hu, Song; Li, Yanhui; Xu, Ruiqiao; Wei, Jinquan; Zhu, Hongwei; Wu, Dehai

    2016-05-04

    Graphene aerogels are highly porous materials with many energy and environmental applications; tailoring the structure and composition of pore walls within the aerogel is the key to those applications. Here, by freeze casting the graphene oxide sheets, we directly fabricated freestanding porous graphene beads containing radially oriented through channels from the sphere center to its surface. Furthermore, we introduced pseudopolymer to make reinforced, functional composite beads with a unique pore morphology. We showed that polymer layers can be coated smoothly on both sides of the pore walls, as well as on the junctions between adjacent pores, resulting in uniform polymer-graphene-polymer sandwiched structures (skeletons) throughout the bead. These composite beads significantly improved the electrochemical properties, with specific capacitances up to 669 F/g and good cyclic stability. Our results indicate that controlled fabrication of homogeneous hierarchical structures is a potential route toward high performance composite electrodes for various energy applications.

  3. Method for Quantitative Determination of Spatial Polymer Distribution in Alginate Beads Using Raman Spectroscopy

    NARCIS (Netherlands)

    Heinemann, Matthias; Meinberg, Holger; Büchs, Jochen; Koß, Hans-Jürgen; Ansorge-Schumacher, Marion B.

    2005-01-01

    A new method based on Raman spectroscopy is presented for non-invasive, quantitative determination of the spatial polymer distribution in alginate beads of approximately 4 mm diameter. With the experimental setup, a two-dimensional image is created along a thin measuring line through the bead

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

    African Journals Online (AJOL)

    Polymer membranes provide a good method of obtaining potable water but, as membranes always foul during water purification, the flux drops with time. Methods of physical cleaning of the polymer membranes, which do not require the plant to be shut down for lengthy periods, are very attractive and also do not generate ...

  5. 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.

  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...

  8. Impact of polymers on dissolution performance of an amorphous gelleable drug from surface-coated beads.

    Science.gov (United States)

    Fan, Chong; Pai-Thakur, Rashmi; Phuapradit, Wantanee; Zhang, Lin; Tian, Hung; Malick, Waseem; Shah, Navnit; Kislalioglu, M Serpil

    2009-04-11

    A non-ionic amorphous active API ((RR)-3((1R)-3-oxocyclopentyl)-2-[3-chloro-4-methyl sulfonyl]phenyl-N-pyrozin-2ylpropanamide) with a glass transition temperature of 60 degrees C and aqueous solubility of 0.8 mg/mL was layered on the cellulose beads by the help of an anionic (Eudragit L100) and a non-ionic (polyvinylpyrrolidone) PVP K30 polymer respectively. An "immediate" and complete release of API from the anionic (Eudragit L100), and "sustained" but incomplete release from the hygroscopic non-ionic polymer coatings were observed. The effect of the PVP K30, and delivery patterns were investigated. Water uptake of the polymers and flow properties of API upon exposure to humidity as well as moisture sorption of beadlets were determined. Drug-polymer interactions and coating morphologies that were examined via near infrared imaging (NIR), microscopy and FTIR, enlightened any possible drug-polymer interaction. From the anionic polymer coating 93.5% API was dissolved in 50 min whereas the non-ionic polymer coating released 60% drug within 5 h. There were no API-polymer interactions as demonstrated by FTIR, implying that, this factor did not play any role in the differences observed in the release profiles. However, gelling, clumping and agglomeration was observed on the surface of the particles coated with PVP which resulted in slow and incomplete release of the drug. The anionic polymer protected API, by preventing its gelling and clumping in situ while the non-ionic polymer promoted gelling. Because API gels at a critical moisture level and at an associated critical time interval, any delivery system that can protect the drug from reaching to the critical moisture level can control API release. The drug was released via surface erosion from the Eudragit L100 coating, whereas PVP K30, the non-ionic polymer, released API via diffusion process. The results indicate that polymer properties can play a critical role in the release mechanism and kinetics of gelleable

  9. A novel statistical spring-bead based network model for self-sensing smart polymer materials

    Science.gov (United States)

    Zhang, Jinjun; Koo, Bonsung; Liu, Yingtao; Zou, Jin; Chattopadhyay, Aditi; Dai, Lenore

    2015-08-01

    This paper presents a multiscale modeling approach to simulating the self-sensing behavior of a load sensitive smart polymer material. A statistical spring-bead based network model is developed to bridge the molecular dynamics simulations at the nanoscale and the finite element model at the macroscale. Parametric studies are conducted on the developed network model to investigate the effects of the thermoset crosslinking degree on the mechanical response of the self-sensing material. A comparison between experimental and simulation results shows that the multiscale framework is able to capture the global mechanical response with adequate accuracy and the network model is also capable of simulating the self-sensing phenomenon of the smart polymer. Finally, the molecular dynamics simulation and network model based simulation are implemented to evaluate damage initiation in the self-sensing material under monotonic loading.

  10. Preparation of an ion-exchangeable polymer bead wrapped with bilayer membrane structures for high performance liquid chromatography.

    Science.gov (United States)

    Haratake, Mamoru; Hidaka, Shuko; Ono, Masahiro; Nakayama, Morio

    2007-04-18

    We synthesized a chromatographic packing material that has a non-covalently attached dihexadecyl phosphate (DHP) bilayer membrane structure on a CA08S, a nonporous-type cationic polymer bead with a diameter ranging from 11 to 14 microm. Confocal fluorescence microscopic and differential scanning calorimetric analyses of the DHP-CA08S complex revealed that the DHP bilayer membrane structures were formed on the surface of the CA08S polymer beads. When the functionality of the DHP-CA08S complex was evaluated in the ion-exchange HPLC of proteins, the retention behavior of the proteins on the DHP-CA08S complex column totally mirrored the anionic property of the DHP bilayer membrane surface, not the cationic property of the CA08S bead. Methylene blue (MB) was eluted from the DHP-CA08S complex column in the isocratic elution mode, but not at all from a CK08S column, a styrene-divinylbenzene based cation-exchange polymer. When the column temperature was elevated from 50 to 60 degrees C, the peak shape of MB on the DHP-CA08S complex column became fairly sharp without a change in its peak area, which mirrored the characteristic phase transition of the DHP bilayer membrane formed on the DHP-CA08S complex.

  11. 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.

  12. 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

    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...

  13. In vivo and in vitro taste masking of ofloxacin and sustained release by forming interpenetrating polymer network beads.

    Science.gov (United States)

    Rajesh, A Michael; Popat, Kiritkumar Mangaldas

    2017-02-01

    Drug-resin complexes (DRCs) of ofloxacin and ion-exchange resins (IERs) were prepared in different ratios of drug/IERs, that is, 1:1, 1:2 and 1:4 (w/w) and investigated for taste masking by in vivo and in vitro release studies. Human volunteers graded AD1:4 (DRC) as tasteless with an average value of 0.3 ± 0.03 and in vitro study showed that AD 1:4 released only 1.70 ± 0.86% of drug at salivary pH within 30s. Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (P-XRD) and differential scanning calorimetry (DSC) studies of AD 1:4 showed the change in the morphology of the drug, that is, from crystalline phase to amorphous phase during complex formation. The release of drug from AD 1:4 was completed within 30 min at gastric pH 1.2 and to extend the release time of drug at gastric pH, it was entrapped with different biopolymers, such as sodium alginate (SA) and sodium carboxymethyl cellulose (SCMC), in the presence of ferric chloride and glutaraldehyde (GA) to form interpenetrating polymer network (IPN) beads. FTIR studies revealed that IPN beads were crosslinked with Fe3+ and GA. The release of drug at gastric and intestinal pH was 14.53 ± 1.52% and 65.86 ± 1.29%, respectively, for a contact time of 10 h. The kinetics release study shows fickian diffusion for ionically crosslinked beads and zero-order release for GA crosslinking beads.

  14. 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.

  15. Modeling studies: Adsorption of aniline blue by using Prosopis Juliflora carbon/Ca/alginate polymer composite beads.

    Science.gov (United States)

    Kumar, M; Tamilarasan, R

    2013-02-15

    The research article describes the experimental and modeling study for the adsorptive removal of aniline blue dye (AB dye) from aqueous matrices using a Prosopis Juliflora modified carbon/Ca/alginate polymer bead as a low cost and eco-friendly adsorbent. The rate of adsorption was investigated under various experimental parameters such as contact time, adsorbent dose, dye concentration, pH and temperature. The kinetics, equilibrium and thermodynamic studies were assessed to find out the efficiency of the adsorption process. The equilibrium uptake capacity of the adsorption process was found with Freundlich and Langmuir adsorption isotherm equations and it was evaluated by dimensionless separation factor (R(L)). The dynamics of adsorption was predicted by pseudo-first order, pseudo-second order Lagergren's equation and intra particle diffusion model. Adsorption feasibility was assessed with thermodynamic parameters such as isosteric heat of adsorption (ΔH°), standard entropy (ΔS°) and Gibbs free energy (ΔG°) using VantHoff plot. The alginate bead was characterized with FTIR spectroscopy and Scanning Electron Microscopy (SEM). Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  16. Functionalized nanocrystal-tagged fluorescent polymer beads: synthesis, physicochemical characterization, and immunolabeling application.

    Science.gov (United States)

    Stsiapura, Vitali; Sukhanova, Alyona; Artemyev, Mikhail; Pluot, Michel; Cohen, Jacques H M; Baranov, Alexandre V; Oleinikov, Vladimir; Nabiev, Igor

    2004-11-15

    A methodology for incorporating solubilized CdSe/ZnS core/shell nanocrystals (NCs) into functionalized carboxylated polystyrene latexes 0.3-1 microm in diameter via a swelling procedure was developed and used for the production of homogeneous, highly fluorescent polymeric beads (HFPBs), which were found to be comparable in brightness to standard polymeric microspheres doped with organic fluorophores and more photostable than the latter by more than 50 times (Fluoresbrite yellow-orange microspheres were used as an example). The three-dimensional (3D) confocal analysis of individual 1-microm HFPB demonstrated that the beads were doped with the NCs almost homogeneously. HFPBs 0.3 microm in diameter were conjugated with anti-mouse polyvalent immunoglobulins and used for immunofluorescent detection of p-glycoprotein, a mediator of the multidrug resistance phenotype, overexpressed in the membrane of MCF7r breast adenocarcinoma cells. The photostability of NCs-tagged HFPBs offers obvious advantages for the reconstruction of 3D confocal fluorescence images of antigen distribution, and their exceptionally high brightness combined with photostability permits the detection of a single antigen molecule using a standard epifluorescence microscope.

  17. 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.

  18. A theoretical analysis of the extraction of heterocyclic organic compounds from an organic phase using chemically mediated electrochemically modulated complexation in ion exchange polymer beads

    Energy Technology Data Exchange (ETDEWEB)

    Ozekin, K.; Noble, R.D.; Koval, C.A.

    1991-01-01

    A cyclical electrochemical process for the removal of heterocyclic organic compounds (pollutants) from an organic solvent using an ion-exchange polymer is analyzed. In this analysis, there are three main steps: In the first step, the polymer beads containing the active form of the complexing agent are contacted with the contaminated (feed) hydrocarbon phase. The pollutant diffuses into the beads and binds with the complexing agent which is in the reduced state. It is a fast reversible reaction. For the second step, the beads which contain a pollutant are contacted with a waste (receiving) phase and a chemical mediator is then used to oxidize the complexing agent and to reduce its affinity towards the pollutant so that it can be released. The oxidation of the complexing agent is an irreversible reaction. This is a moving boundary problem with countercurrent diffusion. For each mole of mediator that goes into the bead, one mole of pollutant exits since each complexing agent binds one pollutant. In the third step, the waste hydrocarbon phase is removed and a second chemical mediator is then used to reduce the complexing agent. The reduction of the complexing agent is also an irreversible reaction. Partial differential equations are used to analyze this process. 26 refs., 9 figs.

  19. Molecularly imprinted polymer beads for clean-up and preconcentration of β-lactamase-resistant penicillins in milk.

    Science.gov (United States)

    Urraca, Javier L; Chamorro-Mendiluce, Raquel; Orellana, Guillermo; Moreno-Bondi, Maria C

    2016-03-01

    This work describes the development and application of class-selective molecularly imprinted polymers (MIPs) for the analysis of beta-lactamase-resistant penicillins, namely cloxacillin (CLOXA), oxacillin (OXA), and dicloxacillin (DICLOXA), in milk samples. Our method is based on molecularly imprinted solid-phase extraction (MISPE) coupled to high-performance liquid chromatography (HPLC) with diode-array detection (DAD). 2-Biphenylylpenicillin (2BPEN), a surrogate with a close resemblance to beta-lactamase-resistant penicillins in terms of size, shape, hydrophobicity, and functionality, was synthesized and used as the template for the polymer synthesis. A MIP library was prepared and screened to select the optimum functional monomer, N-(2-aminoethyl)methacrylamide, and cross-linker, trimethylolpropane trimethacrylate, that provided the best recognition for the target antibiotics. For the MISPE application, the MIPs were prepared in the form of microspheres, using porous silica beads (40-75 μm) as sacrificial scaffolds. The developed MISPE method enables efficient extraction from aqueous samples and analysis of the antimicrobials, when followed by a selective washing with 2 mL acetonitrile-water (20:80 v/v) and elution with 1 mL 0.05 mol L(-1) tetrabutylammonium in methanol. The analytical method was validated according to EU guideline 2002/657/EC. The limits of quantification (S/N = 10) were in the 5.3-6.3 μg kg(-1) range, well below the maximum residue limits (MRLs) currently established. Inter-day mean recoveries were in the range 99-102 % with RSDs below 9 %, improving on the performance of previously reported MISPE methods for the analysis of CLOXA, OXA, or DICLOXA in milk samples.

  20. 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.

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

    Science.gov (United States)

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

    2015-04-01

    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.

  2. 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

  3. Preparation of Alginate Gel Beads Containing Metformin ...

    African Journals Online (AJOL)

    A new emulsion gelation method was used to prepare gel beads for a highly water-soluble drug metformin hydrochloride using sodium alginate as the polymer. The gel beads containing oil was prepared by gently mixing or homogenizing oil and water phase containing sodium alginate which was then extruded into calcium ...

  4. 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.

  5. 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

    2017-12-08

    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, 2017. © 2017 Wiley Periodicals, Inc.

  6. Poly(styrene-divinylbenzene) beads surface functionalized with di-block polymer grafting and multi-modal ligand attachment: performance of reversibly immobilized lipase in ester synthesis.

    Science.gov (United States)

    Bayramoglu, Gulay; Karagoz, Bunyamin; Altintas, Begum; Arica, M Yakup; Bicak, Niyazi

    2011-08-01

    Fibrous poly(styrene-b-glycidylmethacrylate) brushes were grafted on poly(styrene-divinylbenzene) (P(S-DVB)) beads using surface-initiated atom transfer radical polymerization. Tetraethyldiethylenetriamine (TEDETA) ligand was incorporated on P(GMA) block. The ligand attached beads were used for reversible immobilization of lipase. The influences of pH, ionic strength, and initial lipase concentration on the immobilization capacities of the beads have been investigated. Lipase adsorption capacity of the beads was about 78.1 mg/g beads at pH 6.0. The Km value for immobilized lipase was about 2.1-fold higher than that of free enzyme. The thermal, and storage stability of the immobilized lipase also was increased compared to the native lipase. It was observed that the same support enzyme could be repeatedly used for immobilization of lipase after regeneration without significant loss in adsorption capacity or enzyme activity. A lipase from Mucor miehei immobilized on styrene-divinylbenzene copolymer was used to catalyze the direct esterification of butyl alcohol and butyric acid.

  7. NIST/ISAC standardization study: variability in assignment of intensity values to fluorescence standard beads and in cross calibration of standard beads to hard dyed beads.

    Science.gov (United States)

    Hoffman, Robert A; Wang, Lili; Bigos, Martin; Nolan, John P

    2012-09-01

    Results from a standardization study cosponsored by the International Society for Advancement of Cytometry (ISAC) and the US National Institute of Standards and Technology (NIST) are reported. The study evaluated the variability of assigning intensity values to fluorophore standard beads by bead manufacturers and the variability of cross calibrating the standard beads to stained polymer beads (hard-dyed beads) using different flow cytometers. Hard dyed beads are generally not spectrally matched to the fluorophores used to stain cells, and spectral response varies among flow cytometers. Thus if hard dyed beads are used as fluorescence calibrators, one expects calibration for specific fluorophores (e.g., FITC or PE) to vary among different instruments. Using standard beads surface-stained with specific fluorophores (FITC, PE, APC, and Pacific Blue™), the study compared the measured intensity of fluorophore standard beads to that of hard dyed beads through cross calibration on 133 different flow cytometers. Using robust CV as a measure of variability, the variation of cross calibrated values was typically 20% or more for a particular hard dyed bead in a specific detection channel. The variation across different instrument models was often greater than the variation within a particular instrument model. As a separate part of the study, NIST and four bead manufacturers used a NIST supplied protocol and calibrated fluorophore solution standards to assign intensity values to the fluorophore beads. Values assigned to the reference beads by different groups varied by orders of magnitude in most cases, reflecting differences in instrumentation used to perform the calibration. The study concluded that the use of any spectrally unmatched hard dyed bead as a general fluorescence calibrator must be verified and characterized for every particular instrument model. Close interaction between bead manufacturers and NIST is recommended to have reliable and uniformly assigned

  8. Metal-Containing Polystyrene Beads as Standards for Mass Cytometry.

    Science.gov (United States)

    Abdelrahman, Ahmed I; Ornatsky, Olga; Bandura, Dmitry; Baranov, Vladimir; Kinach, Robert; Dai, Sheng; Thickett, Stuart C; Tanner, Scott; Winnik, Mitchell A

    2010-01-01

    We examine the suitability of metal-containing polystyrene beads for the calibration of a mass cytometer instrument, a single particle analyser based on an inductively coupled plasma ion source and a time of flight mass spectrometer. These metal-containing beads are also verified for their use as internal standards for this instrument. These beads were synthesized by multiple-stage dispersion polymerization with acrylic acid as a comonomer. Acrylic acid acts as a ligand to anchor the metal ions within the interior of the beads. Mass cytometry enabled the bead-by-bead measurement of the metal-content and determination of the metal-content distribution. Beads synthesized by dispersion polymerization that involved three stages were shown to have narrower bead-to-bead variation in their lanthanide content than beads synthesized by 2-stage dispersion polymerization. The beads exhibited insignificant release of their lanthanide content to aqueous solutions of different pHs over a period of six months. When mixed with KG1a or U937 cell lines, metal-containing polymer beads were shown not to affect the mass cytometry response to the metal content of element-tagged antibodies specifically attached to these cells.

  9. 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

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

    African Journals Online (AJOL)

    alginate beads (without algae). 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 complete removal of NH4 +-N nd about 95% reduction in phosphate removal within the experimental period ...

  11. 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 ...

  12. Nanofibrous polymeric beads from aramid fibers for efficient bilirubin removal.

    Science.gov (United States)

    Peng, Zihang; Yang, Ye; Luo, Jiyue; Nie, Chuanxiong; Ma, Lang; Cheng, Chong; Zhao, Changsheng

    2016-08-16

    Polymer based hemoperfusion has been developed as an effective therapy to remove the extra bilirubin from patients. However, the currently applied materials suffer from either low removal efficiency or poor blood compatibility. In this study, we report the development of a new class of nanofibrous absorbent that exhibited high bilirubin removal efficiency and good blood compatibility. The Kevlar nanofiber was prepared by dissolving micron-sized Kevlar fiber in proper solvent, and the beads were prepared by dropping Kevlar nanofiber solutions into ethanol. Owing to the nanofiborous structure of the Kevlar nanofiber, the beads displayed porous structures and large specific areas, which would facilitate the adsorption of toxins. In the adsorption test, it was noticed that the beads possessed an adsorption capacity higher than 40 mg g(-1) towards bilirubin. In plasma mimetic solutions, the beads still showed high bilirubin removal efficiency. Furthermore, after incorporating with carbon nanotubes, the beads were found to have increased adsorption capacity for human degradation waste. Moreover, the beads showed excellent blood compatibility in terms of a low hemolysis ratio, prolonged clotting times, suppressed coagulant activation, limited platelet activation, and inhibited blood related inflammatory activation. Additionally, the beads showed good compatibility with endothelial cells. In general, the Kevlar nanofiber beads, which integrated with high adsorption capacity, good blood compatibility and low cytotoxicity, may have great potential for hemoperfusion and some other applications in biomedical fields.

  13. 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...

  14. IDENTIFICATION OF ENCODED BEADS

    DEFF Research Database (Denmark)

    2005-01-01

    The present invention is relates to methods for the identification of spatially encoded beaded or granulated matrices comprising a plurality of immobilised particles. The identification is based on a distance matrix determination or based on a set of geometrical figures, such a triangles...

  15. Glass bead cultivation of fungi

    DEFF Research Database (Denmark)

    Droce, Aida; Sørensen, Jens Laurids; Giese, H.

    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 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...... to specific nutrient factors. •Fungal growth on glass beads eases and improves fungal RNA extraction....

  16. Coated Aerogel Beads

    Science.gov (United States)

    Littman, Howard (Inventor); Plawsky, Joel L. (Inventor); Paccione, John D. (Inventor)

    2014-01-01

    Methods and apparatus for coating particulate material are provided. The apparatus includes a vessel having a top and a bottom, a vertically extending conduit having an inlet in the vessel and an outlet outside of the vessel, a first fluid inlet in the bottom of the vessel for introducing a transfer fluid, a second fluid inlet in the bottom of the vessel for introducing a coating fluid, and a fluid outlet from the vessel. The method includes steps of agitating a material, contacting the material with a coating material, and drying the coating material to produce a coated material. The invention may be adapted to coat aerogel beads, among other materials. A coated aerogel bead and an aerogel-based insulation material are also disclosed.

  17. pH-responsive alginate-based composite hydrogel beads for oral insulin delivery

    OpenAIRE

    HUI PENG LIM

    2017-01-01

    This research attempts to develop a pH-responsive alginate-based composite hydrogel beads for encapsulation and controlled delivery of oral insulin aspart through incorporation of κ-carrageenan as a reinforcement polymer and hydrophobic modification of alginate polymer. The alginate/κ-carrageenan composite hydrogel beads were able to fully retain the insulin in conditions mimicking the stomach and release the insulin in conditions mimicking the intestine at a constant rate. Bioactivity of ins...

  18. Physicochemical Characterization of Alginate Beads Containing Sugars and Biopolymers

    Directory of Open Access Journals (Sweden)

    Tatiana Aguirre Calvo

    2016-01-01

    Full Text Available Alginate hydrogels are suitable for the encapsulation of a great variety of biomolecules. Several alternatives to the conventional alginate formulation are being studied for a broad range of biotechnological applications; among them the addition of sugars and biopolymers arises as a good and economic strategy. Sugars (trehalose and β-cyclodextrin, a cationic biopolymer (chitosan, an anionic biopolymer (pectin, and neutral gums (Arabic, guar, espina corona, and vinal gums provided different characteristics to the beads. Here we discuss the influence of beads composition on several physicochemical properties, such as size and shape, analyzed through digital image analysis besides both water content and activity. The results showed that the addition of a second biopolymer, β-CD, or trehalose provoked more compact beads, but the fact that they were compact not necessarily implies a concomitant increase in their circularity. Espina corona beads showed the highest circularity value, being useful for applications which require a controlled and high circularity, assuring quality control. Beads with trehalose showed lower water content than the rest of the system, followed by those containing galactomannans (espina corona, vinal, and guar gums, revealing polymer structure effects. A complete characterization of the beads was performed by FT-IR, assigning the characteristics bands to each individual component.

  19. 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.

  20. Tetracycline nanoparticles loaded calcium sulfate composite beads for periodontal management.

    Science.gov (United States)

    Sindhura Reddy, N; Sowmya, S; Bumgardner, Joel D; Chennazhi, K P; Biswas, Raja; Jayakumar, R

    2014-06-01

    The objective of this study was to fabricate, characterize and evaluate in vitro, an injectable calcium sulfate bone cement beads loaded with an antibiotic nanoformulation, capable of delivering antibiotic locally for the treatment of periodontal disease. Tetracycline nanoparticles (Tet NPs) were prepared using an ionic gelation method and characterized using DLS, SEM, and FTIR to determine size, morphology, stability and chemical interaction of the drug with the polymer. Further, calcium sulfate (CaSO4) control and CaSO4-Tet NP composite beads were prepared and characterized using SEM, FTIR and XRD. The drug release pattern, material properties and antibacterial activity were evaluated. In addition, protein adsorption, cytocompatibility and alkaline phosphatase activity of the CaSO4-Tet NP composite beads in comparison to the CaSO4 control were analyzed. Tet NPs showed a size range of 130±20nm and the entrapment efficiency calculated was 89%. The composite beads showed sustained drug release pattern. Further the drug release data was fitted into various kinetic models wherein the Higuchi model showed higher correlation value (R(2)=0.9279) as compared to other kinetic models. The composite beads showed antibacterial activity against Staphylococcus aureus and Escherichia coli. The presence of Tet NPs in the composite bead didn't alter its cytocompatibility. In addition, the composite beads enhanced the ALP activity of hPDL cells. The antibacterial and cytocompatible CaSO4-Tet NP composite beads could be beneficial in periodontal management to reduce the bacterial load at the infection site. Tet NPs would deliver antibiotic locally at the infection site and the calcium sulfate cement, would itself facilitate tissue regeneration. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Okra (Hibiscus esculentus) gum-alginate blend mucoadhesive beads for controlled glibenclamide release.

    Science.gov (United States)

    Sinha, Priyanka; Ubaidulla, U; Nayak, Amit Kumar

    2015-01-01

    The utility of isolated okra (Hibiscus esculentus) gum (OG) was evaluated as a potential sustained drug release polymer-blends with sodium alginate in the development of controlled glibenclamide release ionically-gelled beads for oral use. OG was isolated from okra fruits and its solubility, pH, viscosity and moisture content were studied. Glibenclamide-loaded OG-alginate blend beads were prepared using CaCl2 as cross-linking agent through ionic-gelation technique. These ionically gelled beads showed drug entrapment efficiency of 64.19 ± 2.02 to 91.86 ± 3.24%. The bead sizes were within 1.12 ± 0.11 to 1.28 ± 0.15 mm. These glibenclamide-loaded OG-alginate blend beads exhibited sustained in vitro drug release over a prolonged period of 8 h. The in vitro drug release from these OG-alginate beads were followed controlled-release (zero-order) pattern with super case-II transport mechanism. The beads were also characterized by SEM and FTIR. The swelling and degradation of these beads was influenced by the pH of the test medium. These beads also exhibited good mucoadhesivity with goat intestinal mucosa.

  2. 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....

  3. 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.

  4. 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.

  5. 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.

  6. Combined bead polymerization and Cinchona organocatalyst immobilization by thiol–ene addition

    Directory of Open Access Journals (Sweden)

    Kim A. Fredriksen

    2012-07-01

    Full Text Available In this work, we report an unusually concise immobilization of Cinchona organocatalysts using thiol–ene chemistry, in which catalyst immobilization and bead polymerization is combined in a single step. A solution of azo initiator, polyfunctional thiol, polyfunctional alkene and an unmodified Cinchona-derived organocatalyst in a solvent is suspended in water and copolymerized on heating by thiol–ene additions. The resultant spherical and gel-type polymer beads have been evaluated as organocatalysts in catalytic asymmetric transformations.

  7. Combined bead polymerization and Cinchona organocatalyst immobilization by thiol-ene addition.

    Science.gov (United States)

    Fredriksen, Kim A; Kristensen, Tor E; Hansen, Tore

    2012-01-01

    In this work, we report an unusually concise immobilization of Cinchona organocatalysts using thiol-ene chemistry, in which catalyst immobilization and bead polymerization is combined in a single step. A solution of azo initiator, polyfunctional thiol, polyfunctional alkene and an unmodified Cinchona-derived organocatalyst in a solvent is suspended in water and copolymerized on heating by thiol-ene additions. The resultant spherical and gel-type polymer beads have been evaluated as organocatalysts in catalytic asymmetric transformations.

  8. 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

    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...... pronounced phosphotyrosine affinity and selectivity in binding tests using model peptides in acetonitrile rich solutions with a performance surpassing solution polymerized bulk imprinted materials. Tests of the beads for the enrichment of phosphopeptides from tryptic digests of twelve proteins revealed both...

  9. 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.

  10. Synthesis and studies of water-soluble Prussian Blue-type nanoparticles into chitosan beads.

    Science.gov (United States)

    Folch, Benjamin; Larionova, Joulia; Guari, Yannick; Molvinger, Karine; Luna, Carlos; Sangregorio, Claudio; Innocenti, Claudia; Caneschi, Andrea; Guérin, Christian

    2010-10-21

    A new approach to the synthesis of highly stable aqueous colloids of coordination polymer nanoparticles was developed by using water-soluble chitosan beads as template and as stabilizing agent. The method consists in the synthesis of nanocomposite beads containing cyano-bridged coordination polymer nanoparticles via step-by-step coordination of the metal ions and the hexacyanometallate precursors into the chitosan pores and then water solubilization of these as-obtained nanocomposite beads. We obtain a large range of M(2+)/[M'(CN)(6)](3-)/chitosan (where M(2+) = Ni(2+), Cu(2+), Fe(2+), Co(2+), Mn(2+) and M' = Fe(3+) and Cr(3+)) nanocomposite beads and their respective aqueous colloids containing coordination polymer core/chitosan shell nanoparticles. The nanocomposite beads and the corresponding aqueous colloids were studied by Infrared (IR) and UV-Vis spectroscopy, nitrogen sorption (BET), Transmission Electron Microscopy (TEM), High Resolution Transmission Electron Microscopy (HRTEM) and magnetic analyses, which reveal the presence of homogeneously dispersed uniformly-sized cyano-bridged coordination polymer nanoparticles. The detailed studies of the static and dynamic magnetic properties of these nanoparticles show the occurrence of a spin-glass like behavior presumably produced by intra-particle spin disorder due to the low spin exchange energy characterizing these materials.

  11. Preparation of alginate beads containing a prodrug of diethylenetriaminepentaacetic acid

    Science.gov (United States)

    Yang, Yu-Tsai; Di Pasqua, Anthony J.; He, Weiling; Tsai, Tsuimin; Sueda, Katsuhiko; Zhang, Yong; Jay, Michael

    2012-01-01

    A penta-ethyl ester prodrug of the radionuclide decorporation agent diethylenetriaminepentaacetic acid (DTPA), which exists as an oily liquid, was encapsulated in alginate beads by the ionotropic gelation method. An optimal formulation was found by varying initial concentrations of DTPA pentaethyl ester, alginate polymer, Tween 80 surfactant and calcium chloride. All prepared alginate beads were ~1.6 mm in diameter, and the optimal formulation had loading and encapsulation efficiencies of 91.0 ± 1.1 and 72.6 ± 2.2%, respectively, and only 3.2 ± 0.8% water absorption after storage at room temperature in ~80% relative humidity. Moreover, Fourier transform infrared spectroscopy showed that DTPA penta-ethyl ester did not react with excipients during formation of the DTPA penta-ethyl ester-containing alginate beads. Release of prodrug from alginate beads was via anomalous transport, and its stability enhanced by encapsulation. Collectively, these data suggest that this solid dosage form may be suitable for oral administration after radionuclide contamination. PMID:23399237

  12. 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.

  13. Calibration beads containing luminescent lanthanide ion complexes

    Science.gov (United States)

    The reliability of lanthanide luminescence measurements, by both flow cytometry and digital microscopy, will be enhanced by the availability of narrow-band emitting lanthanide calibration beads. These beads can also be used to characterize spectrographic instruments, including mi...

  14. A Wide-Field Fluorescence Microscope Extension for Ultrafast Screening of One-Bead One-Compound Libraries Using a Spectral Image Subtraction Approach.

    Science.gov (United States)

    Heusermann, Wolf; Ludin, Beat; Pham, Nhan T; Auer, Manfred; Weidemann, Thomas; Hintersteiner, Martin

    2016-05-09

    The increasing involvement of academic institutions and biotech companies in drug discovery calls for cost-effective methods to identify new bioactive molecules. Affinity-based on-bead screening of combinatorial one-bead one-compound libraries combines a split-mix synthesis design with a simple protein binding assay operating directly at the bead matrix. However, one bottleneck for academic scale on-bead screening is the unavailability of a cheap, automated, and robust screening platform that still provides a quantitative signal related to the amount of target protein binding to individual beads for hit bead ranking. Wide-field fluorescence microscopy has long been considered unsuitable due to significant broad spectrum autofluorescence of the library beads in conjunction with low detection sensitivity. Herein, we demonstrate how such a standard microscope equipped with LED-based excitation and a modern CMOS camera can be successfully used for selecting hit beads. We show that the autofluorescence issue can be overcome by an optical image subtraction approach that yields excellent signal-to-noise ratios for the detection of bead-associated target proteins. A polymer capillary attached to a semiautomated bead-picking device allows the operator to efficiently isolate individual hit beads in less than 20 s. The system can be used for ultrafast screening of >200,000 bead-bound compounds in 1.5 h, thereby making high-throughput screening accessible to a wider group within the scientific community.

  15. 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.

  16. Formulation and drying of alginate beads for controlled release and stabilization of invertase.

    Science.gov (United States)

    Santagapita, Patricio R; Mazzobre, M Florencia; Buera, M Pilar

    2011-09-12

    Several alternatives to the conventional alginate beads formulation were studied for encapsulation of invertase. Pectin was added to the alginate/enzyme solution while trehalose and β-cyclodextrin were added to the calcium gelation media. The effect of composition changes, freezing, drying methods (freeze, vacuum, or air drying), and thermal treatment were evaluated on invertase stability and its release kinetics from beads. The enzyme release mechanism from wet beads depended on pH. The addition of trehalose, pectin, and β-cyclodextrin modified the bead structure, leading in some cases to a release mechanism that included the relaxation of the polymer chains, besides Fickian diffusion. Enzyme release from vacuum-dried beads was much faster than from freeze-dried beads, probably due to their higher pore size. The inclusion of β-cyclodextrin and especially of pectin prevented enzyme activity losses during bead generation, and trehalose addition was fundamental for achieving adequate invertase protection during freezing, drying, and thermal treatment. Present results showed that several alternatives such as drying method, composition, as well as pH of the relese medium can be managed to control enzyme release.

  17. Alginate-sterculia gum gel-coated oil-entrapped alginate beads for gastroretentive risperidone delivery.

    Science.gov (United States)

    Bera, Hriday; Kandukuri, Saisharan Goud; Nayak, Amit Kumar; Boddupalli, Shashank

    2015-04-20

    Novel floating-mucoadhesive oil-entrapped alginate beads coated with crossslinked alginate-sterculia gum gel membrane was developed for gastroretentive risperidone delivery. Oil-entrapped alginate beads containing risperidone as core were prepared by ionotropic gelation technique. Effects of polymer to drug ratio and oil to water ratio on drug entrapment efficiency (%) and cumulative drug release after 8h (%) were studied to optimize the core beads by a 3(2) factorial design. The optimized beads (F-O) demonstrated drug entrapment efficiency of 83.73±0.81% and cumulative drug release of 70.84±0.27% after 8h. The biopolymeric-coated optimized beads exhibited excellent buoyancy, better ex vivo mucoadhesion and slower drug release rate. The drug release profiles of risperidone-loaded uncoated and coated beads were best fitted in Korsmeyer-Peppas model with Fickian diffusion mechanism. The beads were also examined for the drug-excipients compatibility, drug crystallinity and surface morphology by FTIR, P-XRD and SEM analyses, respectively. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Polymer reptation and nucleosome repositioning.

    Science.gov (United States)

    Schiessel, H; Widom, J; Bruinsma, R F; Gelbart, W M

    2001-05-07

    We consider how beads can diffuse along a chain that wraps them, without becoming displaced from the chain; our proposed mechanism is analogous to the reptation of "stored length" in more familiar situations of polymer dynamics. The problem arises in the case of globular aggregates of proteins (histones) that are wound by DNA in the chromosomes of plants and animals; these beads (nucleosomes) are multiply wrapped and yet are able to reposition themselves over long distances, while remaining bound by the DNA chain.

  19. Direct friction measurement in draw bead testing

    DEFF Research Database (Denmark)

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

    2005-01-01

    The application of draw beads in sheet metal stamping ensures controlled drawing-in of flange parts. Lubrication conditions in draw beads are severe due to sliding under simultaneous bending. Based on the original draw bead test design by Nine [1] comprehensive studies of friction in draw beads...... 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...... and a freely rotating tool respectively, an approach, which inevitably implies large uncertainties due to scatter in the experimental conditions. In order to avoid this problem a new draw bead test is proposed by the authors measuring the friction force acting on the tool radius directly by a build...

  20. In vitro release of metformin from iron (III) cross-linked alginate-carboxymethyl cellulose hydrogel beads.

    Science.gov (United States)

    Swamy, Bala Yerri; Yun, Yeoung-Sang

    2015-01-01

    In the present study, sodium alginate (NaAlg)/sodium carboxymethyl cellulose (NaCMC) blend hydrogel beads were prepared in ferric chloride solution. The developed hydrogel beads exhibited pH sensitive for deliver Metformin hydrochloride (MH). Preparation conditions of the beads (ferric chloride solution) were significantly affected the encapsulation efficiency, swelling and in vitro release profiles of the beads. Swelling studies were accomplished in gastric and intestine stimuli atmosphere at 37°C. The swelling studies reveal that the beads at pH 7.4 showed higher swelling properties compare to pH 1.2. Exterior morphology of beads was analyzed by scanning electron microscope. SEM indicates the surface of the beads is spherical with smooth surface and size of beads drastically reduced with increasing crosslinker concentration. The crosslinking reaction between NaAlg and NaCMC with ferric chloride was confirmed by FTIR analysis. XRD analysis indicates that MH drug molecularly dispersed in the polymer matrix. In vitro release studies of MH loaded beads showed higher release profiles at pH 7.4 compared to pH 1.2. The polymeric matrices followed slightly deviation with Fickian diffusion and fit for experimental co-relation (r(2)) values. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. The profile of adsorbed plasma and serum proteins on methacrylic acid copolymer beads: Effect on complement activation.

    Science.gov (United States)

    Wells, Laura A; Guo, Hongbo; Emili, Andrew; Sefton, Michael V

    2017-02-01

    Polymer beads made of 45% methacrylic acid co methyl methacrylate (MAA beads) promote vascular regenerative responses in contrast to control materials without methacrylic acid (here polymethyl methacrylate beads, PMMA). In vitro and in vivo studies suggest that MAA copolymers induce differences in macrophage phenotype and polarization and inflammatory responses, presumably due to protein adsorption differences between the beads. To explore differences in protein adsorption in an unbiased manner, we used high resolution shotgun mass spectrometry to identify and compare proteins that adsorb from human plasma or serum onto MAA and PMMA beads. From plasma, MAA beads adsorbed many complement proteins, such as C1q, C4-related proteins and the complement inhibitor factor H, while PMMA adsorbed proteins, such as albumin, C3 and apolipoproteins. Because of the differences in complement protein adsorption, follow-up studies focused on using ELISA to assess complement activation. When incubated in serum, MAA beads generated significantly lower levels of soluble C5b9 and C3a/C3adesarg in comparison to PMMA beads, indicating a decrease in complement activation with MAA beads. The differences in adsorbed protein on the two materials likely alter subsequent cell-material interactions that ultimately result in different host responses and local vascularization. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Removal of diethyl phthalate from aqueous phase using magnetic poly(EGDMA-VP) beads

    Energy Technology Data Exchange (ETDEWEB)

    Tuemay Oezer, Elif [Department of Chemistry, Uludag University, Bursa (Turkey); Osman, Bilgen, E-mail: bilgeno@uludag.edu.tr [Department of Chemistry, Uludag University, Bursa (Turkey); Kara, Ali; Besirli, Necati; Guecer, Seref [Department of Chemistry, Uludag University, Bursa (Turkey); Soezeri, Hueseyin [TUBITAK-UME, National Metrology Institute, PO Box 54 TR-41470, Gebze/Kocaeli (Turkey)

    2012-08-30

    Highlights: Black-Right-Pointing-Pointer Magnetic beads were prepared for removal of diethyl phthalate (DEP). Black-Right-Pointing-Pointer Total capacity of the beads was determined as 98.9 mg DEP per gram polymer. Black-Right-Pointing-Pointer Magnetic beads were regenerated easily and reused for DEP adsorption. Black-Right-Pointing-Pointer Adsorption isotherms, kinetics and thermodynamics were elucidated. - Abstract: The barium hexaferrite (BaFe{sub 12}O{sub 19}) containing magnetic poly(ethylene glycol dimethacrylate-vinyl pyridine), (mag-poly(EGDMA-VP)) beads (average diameter = 53-212 {mu}m) were synthesized and characterized. Their use as an adsorbent in the removal of diethyl phthalate (DEP) from an aqueous solution was investigated. The mag-poly(EGDMA-VP) beads were prepared by copolymerizing of 4-vinyl pyridine (VP) with ethylene glycol dimethacrylate (EGDMA). The mag-poly(EGDMA-VP) beads were characterized by N{sub 2} adsorption/desorption isotherms (BET), vibrating sample magnetometer (VSM), X-ray powder diffraction (XRD), elemental analysis, scanning electron microscope (SEM) and swelling studies. At a fixed solid/solution ratio, the various factors affecting the adsorption of DEP from aqueous solutions such as pH, initial concentration, contact time and temperature were analyzed. The maximum DEP adsorption capacity of the mag-poly(EGDMA-VP) beads was determined as 98.9 mg/g at pH 3.0, 25 Degree-Sign C. All the isotherm data can be fitted with both the Langmuir and the Dubinin-Radushkevich isotherm models. The pseudo first-order, pseudo-second-order, Ritch-second-order and intraparticle diffusion models were used to describe the adsorption kinetics. The thermodynamic parameters obtained indicated the exothermic nature of the adsorption. The DEP adsorption capacity did not change after 10 batch successive reactions, demonstrating the usefulness of the magnetic beads in applications.

  3. Comparison of the performances of four hydrophilic polymers as supports for lipase immobilisation

    OpenAIRE

    Toscano, Lydia; Montero, Gisela; Stoytcheva, Margarita; Cervantes, Lourdes; Gochev, Velizar

    2014-01-01

    Four hydrophilic polymers in the form of beads ? chitosan, alginate, alginate/polyvinyl alcohol (PVA), and chitosan-coated alginate ? were used as supports for lipase immobilisation. Hydrogel beads were characterised by bead-size-distribution estimation, surface morphology studies, and polymer interactions assessment. Matrix performances ? loading efficiency, immobilisation yield, enzyme activity, and stability retention ? were evaluated and compared. Although the loading efficiency of the ch...

  4. 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.

  5. Bead mediated separation of microparticles in droplets.

    Directory of Open Access Journals (Sweden)

    Sida Wang

    Full Text Available Exchange of components such as particles and cells in droplets is important and highly desired in droplet microfluidic assays, and many current technologies use electrical or magnetic fields to accomplish this process. Bead-based microfluidic techniques offer an alternative approach that uses the bead's solid surface to immobilize targets like particles or biological material. In this paper, we demonstrate a bead-based technique for exchanging droplet content by separating fluorescent microparticles in a microfluidic device. The device uses posts to filter surface-functionalized beads from a droplet and re-capture the filtered beads in a new droplet. With post spacing of 7 μm, beads above 10 μm had 100% capture efficiency. We demonstrate the efficacy of this system using targeted particles that bind onto the functionalized beads and are, therefore, transferred from one solution to another in the device. Binding capacity tests performed in the bulk phase showed an average binding capacity of 5 particles to each bead. The microfluidic device successfully separated the targeted particles from the non-targeted particles with up to 98% purity and 100% yield.

  6. Removal of americium from aqueous nitrate solutions by sorption onto PC88A-impregnated macroporous polymeric beads.

    Science.gov (United States)

    Pathak, S K; Tripathi, S C; Singh, K K; Mahtele, A K; Kumar, Manmohan; Gandhi, P M

    2014-08-15

    The removal of Am (III) ions from aqueous solutions was studied by solid-liquid extraction using indigenously synthesized Extractant Impregnated Macroporous Polymeric Beads (EIMPBs). These beads were prepared by an in situ phase inversion method using polyethersulfone (PES) as base polymer and 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (PC88A) as an extractant. The synthesized EIMPBs were characterized by FTIR, TGA and SEM techniques. The batch equilibration study using these beads for the uptake of Am (III) was carried out as a function of parameters, like pH, equilibration time, Am (III) concentration, etc. The blank polymeric beads, without PC88A, have shown negligible sorption of Am (III) under the experimental conditions. The experimental data on the sorption behavior of Am (III) on the polymeric beads fitted well in the pseudo-second-order kinetics model. The synthesized polymeric beads exhibited very good sorption capacity for Am (III) at pH 3. The reusability of the beads was also ascertained by repetitive sorption/desorption of Am (III) up to 10 cycles of operation, without any significant change in their sorption characteristics. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Formulation and in vitro and in vivo availability of diclofenac sodium enteric-coated beads.

    Science.gov (United States)

    Hosny, E A; el-Mahrouk, G M; Gouda, M W

    1998-07-01

    Diclofenac sodium enteric-coated beads were prepared using the conventional pan coating technique. Eudragit L100 was used as a pH-dependent release-controlling polymer. The beads were evaluated for their particle size distribution, drug loading efficiency, flowability, in vitro release in 0.1 N HCl (pH 1.2) and phosphate buffer (pH 6.8), and bioavailability in beagle dogs relative to the commercial enteric-coated tablets Voltaren. The beads showed a narrow particle size distribution in which 83% of the beads were in the range of 1-2 mm. The actual yield of the beads was 90.5% and their drug loading was 92%. The beads released about 8% of the drug during 2 hr of dissolution in 0.1 N HCl, and the commercial tablets released no drug. In phosphate buffer (pH 6.8) both formulations released their drug content in 1 hr. Both formulations are, therefore, in compliance with the USP requirements for release from enteric-coated dosage forms. The in vivo availability study in six beagle dogs revealed that the formulated enteric-coated beads filled in hard gelatin capsules had a 197.54% bioavailability relative to that of the commercial Voltaren tablets. The tablets showed a significantly lower (p 0.05) higher peak plasma concentration (Cmax) of 6.77 +/- 0.67 micrograms/ml compared to 5.88 +/- 7.38 micrograms/ml for the tablets. The time to reach peak (Tmax) values were 2 +/- 1.48 and 2.25 +/- 1.08 hr for the capsules and tablets, respectively. The capsules showed less interdog variability with respect to Cmax (CV% 34.6) and AUC (CV% 19.55) compared to CV% 79.9 and 111.76, respectively, for the commercial tablets.

  8. Preparation and characterization of alginate and psyllium beads containing Lactobacillus acidophilus.

    Science.gov (United States)

    Lotfipour, Farzaneh; Mirzaeei, Shahla; Maghsoodi, Maryam

    2012-01-01

    This paper describes preparation and characterization of beads of alginate and psyllium containing probiotic bacteria of Lactobacillus acidophilus DMSZ20079. Twelve different formulations containing alginate (ALG) and alginate-psyllium (ALG-PSL) were prepared using extrusion technique. The prepared beads were characterized in terms of size, morphology and surface properties, encapsulation efficiency, viabilities in acid (pH 1.8, 2 hours) and bile (0.5% w/v, 2 hours) conditions, and release in simulated colon pH conditions. The results showed that spherical beads with narrow size distribution ranging from 1.59 ± 0.04 to 1.67 ± 0.09 mm for ALG and from 1.61 ± 0.06 to 1.80 ± 0.07 mm for ALG-PSL with encapsulation efficiency higher than 98% were achieved. Furthermore, addition of PSL into ALG enhanced the integrity of prepared beads in comparison with ALG formulations. The results indicated that incorporation of PSL into alginate beads improved viability of the bacteria in acidic conditions as well as bile conditions. Also, stimulating effect of PSL on the probiotic bacteria was observed through 20-hour incubation in simulated colonic pH solution. According to our in vitro studies, PSL can be a suitable polymer candidate for partial substitution with ALG for probiotic coating.

  9. Preparation and Characterization of Alginate and Psyllium Beads Containing Lactobacillus acidophilus

    Directory of Open Access Journals (Sweden)

    Farzaneh Lotfipour

    2012-01-01

    Full Text Available This paper describes preparation and characterization of beads of alginate and psyllium containing probiotic bacteria of Lactobacillus acidophilus DMSZ20079. Twelve different formulations containing alginate (ALG and alginate-psyllium (ALG-PSL were prepared using extrusion technique. The prepared beads were characterized in terms of size, morphology and surface properties, encapsulation efficiency, viabilities in acid (pH 1.8, 2 hours and bile (0.5% w/v, 2 hours conditions, and release in simulated colon pH conditions. The results showed that spherical beads with narrow size distribution ranging from 1.59±0.04 to 1.67±0.09 mm for ALG and from 1.61±0.06 to 1.80±0.07 mm for ALG-PSL with encapsulation efficiency higher than 98% were achieved. Furthermore, addition of PSL into ALG enhanced the integrity of prepared beads in comparison with ALG formulations. The results indicated that incorporation of PSL into alginate beads improved viability of the bacteria in acidic conditions as well as bile conditions. Also, stimulating effect of PSL on the probiotic bacteria was observed through 20-hour incubation in simulated colonic pH solution. According to our in vitro studies, PSL can be a suitable polymer candidate for partial substitution with ALG for probiotic coating.

  10. Formulation and evaluation of domperidone loaded mineral oil entrapped emulsion gel (MOEG) buoyant beads.

    Science.gov (United States)

    Singh, Inderbir; Kumar, Pradeep; Singh, Harinderjit; Goyal, Malvika; Rana, Vikas

    2011-01-01

    Alginate based mineral oil entrapped emulsion gel (MOEG) buoyant beads of domperidone were prepared by emulsion gelation technique. The prepared beads were evaluated for particle size, surface morphology, buoyancy, actual drug content and entrapment efficiency. Effect of different oils (castor oil, olive oil and linseed oil) and oil concentrations (10%, 15% and 20%, w/w) on uniformity, homogeneity and integrity of the beads was also studied. Density of the formulated beads was found to be ranging between 0.101 and 0.182 g/cm3. The results of the in vitro drug release indicated that linseed oil showed to be good release retardant compared to castor oil and olive oil. Moreover, the beads formulated using 15%, w/w linseed oil were more uniform in shape, exhibited maximum buoyancy and minimal oil leakage. Diffusion exponent (n) value varied from 0.4855 to 0.7710 indicating anomalous drug release behavior involving swelling, diffusion and/or erosion of the polymer matrix.

  11. Novel mesalamine-loaded beads in tablets for delayed release of drug to the colon.

    Science.gov (United States)

    Nguyen, Chien; Christensen, J Mark; Ayres, James W

    2012-01-01

    Novel 'beads-in-a-tablet' formulations (total weight ∼740-780 mg) have been prepared that meet USP 31 requirements for Delayed Release of mesalamine. Several methods are presented that overcome breakage of beads during tablet compaction were explored. Bead formulations comprise a combination of extrusion and spheronization to produce a relatively high drug load (80%), followed by coating (25%) with a colonic-targeted drug release polymer (polymethacrylates, Eudragit(®) S100), overcoated (3%) with hydroxypropyl methylcellulose (Opadry(®)) to improve bead binding and compactability, and using 20% coat of lactose/sodium starch glycolate (Explotab(®)) as binder/disintegrant/cushioning agent, thus allowing a sufficiently thick coating to be uniform and without being broken during tablet compaction. Then, the aforementioned beads were compressed into tablets at 1500 pounds of pressure containing 400 mg of mesalamine, and finally coating the compressed tablets with Surelease(®) (ethylcellulose):Opadry(®) = 1:0.5 ranging from 1.5-2.5% weight gain; the resulting tablets met USP 31 dissolution requirements for delayed release tablets.

  12. Magnetic Pycnoporus sanguineus-Loaded Alginate Composite Beads for Removing Dye from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Chih-Hui Yang

    2014-06-01

    Full Text Available Dye pollution in wastewater is a severe environmental problem because treating water containing dyes using conventional physical, chemical, and biological treatments is difficult. A conventional process is used to adsorb dyes and filter wastewater. Magnetic filtration is an emerging technology. In this study, magnetic Pycnoporus sanguineus-loaded alginate composite beads were employed to remove a dye solution. A white rot fungus, P. sanguineus, immobilized in alginate beads were used as a biosorbent to remove the dye solution. An alginate polymer could protect P. sanguineus in acidic environments. Superparamagnetic nanomaterials, iron oxide nanoparticles, were combined with alginate gels to form magnetic alginate composites. The magnetic guidability of alginate composites and biocompatibility of iron oxide nanoparticles facilitated the magnetic filtration and separation processes. The fungus cells were immobilized in loaded alginate composites to study the influence of the initial dye concentration and pH on the biosorption capacity. The composite beads could be removed easily post-adsorption by using a magnetic filtration process. When the amount of composite beads was varied, the results of kinetic studies of malachite green adsorption by immobilized cells of P. sanguineus fitted well with the pseudo-second-order model. The results indicated that the magnetic composite beads effectively adsorbed the dye solution from wastewater and were environmentally friendly.

  13. Influence of cross-linking agent type and chitosan content on the performance of pectinate-chitosan beads aimed for colon-specific drug delivery.

    Science.gov (United States)

    Maestrelli, F; Cirri, M; Mennini, N; Bragagni, M; Zerrouk, N; Mura, P

    2012-09-01

    Pectinate-chitosan-beads aimed for colon theophylline delivery have been developed. The effect of zinc or calcium ions as cross-linking agent, and of chitosan concentration on the properties and colon-targeting performance of beads was investigated. Beads were characterized for morphology, entrapment efficiency and mucoadhesion properties. Zn-pectinate-chitosan beads formed a stronger gel network than the Ca-containing ones, enabling a greater entrapment efficiency, which further increased with chitosan content, probably due to polyelectrolyte complexes formation. Transport studies across Caco-2 cells evidenced a significant (p > 0.05) drug permeation increase from all beads with respect to drug alone, attributable to the enhancer and/or mucoadhesion properties of the polymers, and Ca-pectinate-chitosan beads were more effective than the Zn-containing ones. Beads formulated as enteric-coated tablets demonstrated good colon-targeting properties, and no differences were observed in drug-release profiles from Zn- or Ca-pectinate-chitosan beads. Therefore, Ca-pectinate-chitosan beads emerged as the choice formulation, joining colon-targeting specificity with better permeation enhancer power.

  14. 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 ...

  15. 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

  16. RADICAL GRAFTING OF POLY(METHYL METHACRYLATE) ONTO SILICON-WAFERS, GLASS SLIDES AND GLASS-BEADS

    NARCIS (Netherlands)

    FOLKERSMA, R; CHALLA, G; SCHOUTEN, AJ

    1991-01-01

    Poly(methyl methacrylate) was grafted onto glass beads, glass slides and silicon wafers using an immobilized radical initiator. The polymeric monolayers had thicknesses varying from a few hundred to 4000 angstrom, being up to 10 times larger than the radii of gyration of comparable free polymers.

  17. 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.

  18. Beaded streams of Arctic permafrost landscapes

    Science.gov (United States)

    Arp, C. D.; Whitman, M. S.; Jones, B. M.; Grosse, G.; Gaglioti, B. V.; Heim, K. C.

    2014-07-01

    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 inventory 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-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 relatively stable form 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 stream gulches effectively insulates river 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 stratify thermally, 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-1, yet channel runs still move water rapidly between pools

  19. 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.

  20. Jeffamine derivatized TentaGel beads and poly(dimethylsiloxane) microbead cassettes for ultrahigh-throughput in situ releasable solution-phase cell-based screening of one-bead-one-compound combinatorial small molecule libraries.

    Science.gov (United States)

    Townsend, Jared B; Shaheen, Farzana; Liu, Ruiwu; Lam, Kit S

    2010-09-13

    A method to efficiently immobilize and partition large quantities of microbeads in an array format in microfabricated poly(dimethylsiloxane) (PDMS) cassette for ultrahigh-throughput in situ releasable solution-phase cell-based screening of one-bead-one-compound (OBOC) combinatorial libraries is described. Commercially available Jeffamine triamine T-403 (∼440 Da) was derivatized such that two of its amino groups were protected by Fmoc and the remaining amino group capped with succinic anhydride to generate a carboxyl group. This resulting trifunctional hydrophilic polymer was then sequentially coupled two times to the outer layer of topologically segregated bilayer TentaGel (TG) beads with solid phase peptide synthesis chemistry resulting in beads with increased loading capacity, hydrophilicity, and porosity at the outer layer. We have found that such bead configuration can facilitate ultrahigh-throughput in situ releasable solution-phase screening of OBOC libraries. An encoded releasable OBOC small molecule library was constructed on Jeffamine derivatized TG beads with library compounds tethered to the outer layer via a disulfide linker and coding tags in the interior of the beads. Compound-beads could be efficiently loaded (5-10 min) into a 5 cm diameter Petri dish containing a 10,000-well PDMS microbead cassette, such that over 90% of the microwells were each filled with only one compound-bead. Jurkat T-lymphoid cancer cells suspended in Matrigel were then layered over the microbead cassette to immobilize the compound-beads. After 24 h of incubation at 37 °C, dithiothreitol was added to trigger the release of library compounds. Forty-eight hours later, MTT reporter assay was used to identify regions of reduced cell viability surrounding each positive bead. From a total of about 20,000 beads screened, 3 positive beads were detected and physically isolated for decoding. A strong consensus motif was identified for these three positive compounds. These compounds

  1. Heterogeneous immunoassays using magnetic beads on a digital microfluidic platform.

    Science.gov (United States)

    Sista, Ramakrishna S; Eckhardt, Allen E; Srinivasan, Vijay; Pollack, Michael G; Palanki, Srinivas; Pamula, Vamsee K

    2008-12-01

    A digital microfluidic platform for performing heterogeneous sandwich immunoassays based on efficient handling of magnetic beads is presented in this paper. This approach is based on manipulation of discrete droplets of samples and reagents using electrowetting without the need for channels where the droplets are free to move laterally. Droplet-based manipulation of magnetic beads therefore does not suffer from clogging of channels. Immunoassays on a digital microfluidic platform require the following basic operations: bead attraction, bead washing, bead retention, and bead resuspension. Several parameters such as magnetic field strength, pull force, position, and buffer composition were studied for effective bead operations. Dilution-based washing of magnetic beads was demonstrated by immobilizing the magnetic beads using a permanent magnet and splitting the excess supernatant using electrowetting. Almost 100% bead retention was achieved after 7776-fold dilution-based washing of the supernatant. Efficient resuspension of magnetic beads was achieved by transporting a droplet with magnetic beads across five electrodes on the platform and exploiting the flow patterns within the droplet to resuspend the beads. All the magnetic-bead droplet operations were integrated together to generate standard curves for sandwich heterogeneous immunoassays on human insulin and interleukin-6 (IL-6) with a total time to result of 7 min for each assay.

  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. Cooling Rates of Lunar Volcanic Glass Beads

    Science.gov (United States)

    Hui, Hejiu; Hess, Kai-Uwe; Zhang, Youxue; Peslier, Anne; Lange, Rebecca; Dingwell, Donald; Neal, Clive

    2016-01-01

    It is widely accepted that the Apollo 15 green and Apollo 17 orange glass beads are of volcanic origin. The diffusion profiles of volatiles in these glass beads are believed to be due to degassing during eruption (Saal et al., 2008). The degree of degassing depends on the initial temperature and cooling rate. Therefore, the estimations of volatiles in parental magmas of lunar pyroclastic deposits depend on melt cooling rates. Furthermore, lunar glass beads may have cooled in volcanic environments on the moon. Therefore, the cooling rates may be used to assess the atmospheric condition in an early moon, when volcanic activities were common. The cooling rates of glasses can be inferred from direct heat capacity measurements on the glasses themselves (Wilding et al., 1995, 1996a,b). This method does not require knowledge of glass cooling environments and has been applied to calculate the cooling rates of natural silicate glasses formed in different terrestrial environments. We have carried out heat capacity measurements on hand-picked lunar glass beads using a Netzsch DSC 404C Pegasus differential scanning calorimeter at University of Munich. Our preliminary results suggest that the cooling rate of Apollo 17 orange glass beads may be 12 K/min, based on the correlation between temperature of the heat capacity curve peak in the glass transition range and glass cooling rate. The results imply that the parental magmas of lunar pyroclastic deposits may have contained more water initially than the early estimations (Saal et al., 2008), which used higher cooling rates, 60-180 K/min in the modeling. Furthermore, lunar volcanic glass beads could have been cooled in a hot gaseous medium released from volcanic eruptions, not during free flight. Therefore, our results may shed light on atmospheric condition in an early moon.

  4. Importance of the solvation degree of peptide-resin beads for amine groups determination by the picric acid method

    Directory of Open Access Journals (Sweden)

    Cilli Eduardo M.

    2000-01-01

    Full Text Available The classic and important picric acid method used in polymers biochemical and chemical fields of polymers for amine group quantification was chosen in this work as a model for evaluating the influence of the resin bead solvation during an analytical procedure. It was observed that this method, proposed almost three decades ago, failed to quantify amine groups of peptidyl-resin containing aggregating and polar sequence. This was due to inefficient solvation of resin beads when only CH2Cl2 was used for picrate anion binding and subsequent washing steps. It was demonstrated that the use of CH2Cl2/DMF (dimethylformamide and CH2Cl2/EtOH solutions during these steps allows correct determination of peptidyl-resin amine groups. Besides the importance for the solid phase peptide synthesis methodology itself, these findings also represent the first quantitative demonstration of the relationship between solvation degree and the efficiency of a polymer-supported analytical method.

  5. Bead Capture on Magnetic Sensors in a Microfluidic System

    DEFF Research Database (Denmark)

    Østerberg, Frederik Westergaard; Dalslet, Bjarke Thomas; Damsgaard, Christian Danvad

    2009-01-01

    The accumulation of magnetic beads by gravitational sedimentation and magnetic capture on a planar Hall-effect sensor integrated in a microfluidic channel is studied systematically as a function of the bead concentration, the fluid flow rate, and the sensor bias current. It is demonstrated...... the fluid flow is defined by the localized magnetic fields from the sensor....... that the sedimentation flux is proportional to the bead concentration and has a power law relation to the fluid flow rate. The mechanisms for the bead accumulation are investigated and it is found that gravitational sedimentation dominates the bead accumulation, whereas the stability of the sedimented beads against...

  6. Bead and Process for Removing Dissolved Metal Contaminants

    Energy Technology Data Exchange (ETDEWEB)

    Summers, Bobby L., Jr.; Bennett, Karen L.; Foster, Scott A.

    2005-01-18

    A bead is provided which comprises or consists essentially of activated carbon immobilized by crosslinked poly (carboxylic acid) binder, sodium silicate binder, or polyamine binder. The bead is effective to remove metal and other ionic contaminants from dilute aqueous solutions. A method of making metal-ion sorbing beads is provided, comprising combining activated carbon, and binder solution (preferably in a pin mixer where it is whipped), forming wet beads, and heating and drying the beads. The binder solution is preferably poly(acrylic acid) and glycerol dissolved in water and the wet beads formed from such binder solution are preferably heated and crosslinked in a convection oven.

  7. The development of geotextiles incorporating slow-release phosphate beads for the maintenance of oil degrading bacteria in permeable pavements.

    Science.gov (United States)

    Spicer, G E; Lynch, D E; Coupe, S J

    2006-01-01

    The development of a self-fertilising geotextile mat designed to provide a sustained slow-release of required inorganic nutrients for the growth of oil degrading microorganisms in porous pavement systems (PPS) is reported. The system comprises a geotextile spun from polymer fibres containing spherical phosphated polymer beads that release phosphate upon contact with water at a desirable level for microbial growth. Initial results using model PPS have shown that the self-fertilising geotextile system works extremely effectively as increased microbial activity has been observed throughout the experiment, illustrating that the oil-degrading bacteria can effectively utilise this polymer composite as a suitable nutrient source.

  8. 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 (Qm) 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 (pHPZC) 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 Qm was negligible. From the design matrix and results, increased Qm 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.

  9. 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.

  10. Cutting Tool For Shaving Weld Beads

    Science.gov (United States)

    Hoffman, David S.; Mcferrin, David C.; Daniel, Ronald L., Jr.; Coby, John B., Jr.; Dawson, Sidney G.

    1995-01-01

    Cutting tool proposed for use in shaving weld beads flush with adjacent surfaces of weldments. Modified version of commercial pneumatically driven rotary cutting tool, cutting wheel of which turns at speeds sufficient for machining nickel alloys, titanium, and stainless steels. Equipped with forward-mounted handle and rear-mounted skid plate to maximize control and reduce dependence on skill of technician.

  11. 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...... metabolite production to agar-cultivation but with an easier and more pure RNA-extraction of total fungal mycelia....

  12. bEADS Extended Actuated Digital Shaker

    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...

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

    Science.gov (United States)

    Inkyo, M.; Tahara, T.; Imajyo, Y.

    2011-10-01

    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.

  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. 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...

  16. In situ generation of sodium alginate/hydroxyapatite nanocomposite beads as drug-controlled release matrices.

    Science.gov (United States)

    Zhang, J; Wang, Q; Wang, A

    2010-02-01

    In order to find a new way to slow down the release of drugs and to solve the burst release problem of drugs from traditionally used hydrogel matrices, a series of novel pH-sensitive sodium alginate/hydroxyapatite (SA/HA) nanocomposite beads was prepared by the in situ generation of HA micro-particles in the beads during the sol-gel transition process of SA. The SA/HA nanocomposites were characterized by Fourier transform IR spectroscopy, X-ray fluorescence spectrometry, scanning electron microscopy and field emission SEM in order to reveal their composition and surface morphology as well as the role that the in situ generated HA micro-particles play. The factors influencing the swelling behavior, drug loading and controlled release behavior of the SA/HA nanocomposite beads were also investigated using diclofenac sodium (DS) as the model drug. The HA micro-particles act as inorganic crosslinkers in the nanocomposites, which could contract and restrict the movability of the SA polymer chains, and then change the surface morphology and decrease the swell ratio. Meanwhile, the entrapment efficiency of DS was improved, and the burst release of DS was overcome. The factors (including concentration of Ca(2+), reaction time and temperature) affecting the growth of HA micro-particles have a clear influence on the entrapment efficiency and release rate of DS. In this work, the nanocomposite beads prepared under optimum condition could prolong the release of DS for 8h more compared with the pristine SA hydrogel beads.

  17. A model for magnetic bead microrheometry

    Energy Technology Data Exchange (ETDEWEB)

    Lunov, Oleg [Department of Biophysics, Donetsk National University, St. Shorsa 46a, Donetsk (Ukraine)]. E-mail: loonevoleg@rambler.ru; Bespalova, Svetlana [Department of Biophysics, Donetsk National University, St. Shorsa 46a, Donetsk (Ukraine); Zablotskii, Vitalii [Laboratory of Magnetism, University of Bialystok, Lipowa 41, Bialystok 15-424 (Poland); Institute of Physics ASCR, Na Slovance 2 , 18221 Prague 8 (Czech Republic)

    2007-04-15

    Mechanical properties of a cell play an important role in the essential cellular functions such as mechanotransduction, shape stability, motility, apoptosis and DNA synthesis. The viscoelasticity of the cytoplasm is a crucial physical parameter for many cellular processes. In this work, we develop a new model allowing us to determine viscoelastic parameters of the cytoplasm (shear elastic modulus, the effective viscosities and the strain relaxation time) of cells. The model describes the rotation of magnetic chains consisting of 3-4 nanoparticles under the influence of rotating external magnetic fields. As the bead rotates, mechanical stresses opposing that rotation are developed within the cell and from the measured angular displacement of the bead, we can extract the viscoelastic parameters by fitting the experimental data with our model. The model gives the possibility for a general description of various phenomena in magnetorheological suspensions.

  18. Removal and recovery of toxic metal ions from aqueous waste sites using polymer pendant ligands

    Energy Technology Data Exchange (ETDEWEB)

    Fish, D. [Lawrence Berkeley National Lab., CA (United States)

    1996-10-01

    The purpose of this project is to investigate the use of polymer pendant ligand technology to remove and recover toxic metal ions from DOE aqueous waste sites. Polymer pendant lgiands are organic ligands, anchored to crosslinked, modified divinylbenzene-polystyrene beads, that can selectively complex metal ions. The metal ion removal step usually occurs through a complexation or ion exchange phenomena, thus recovery of the metal ions and reuse of the beads is readily accomplished.

  19. Polyelectrolyte Complex Beads by Novel Two-Step Process for Improved Performance of Viable Whole-Cell Baeyer-Villiger Monoxygenase by Immobilization

    Directory of Open Access Journals (Sweden)

    Tomáš Krajčovič

    2017-11-01

    Full Text Available A novel immobilization matrix for the entrapment of viable whole-cell Baeyer–Villiger monooxygenase was developed. Viable recombinant Escherichia coli cells overexpressing cyclohexanone monooxygenase were entrapped in polyelectrolyte complex beads prepared by a two-step reaction of oppositely-charged polymers including highly defined cellulose sulphate. Immobilized cells exhibited higher operational stability than free cells during 10 repeated cycles of Baeyer–Villiger biooxidations of rac-bicyclo[3.2.0]hept-2-en-6-one to the corresponding lactones (1R,5S-3-oxabicyclo-[3.3.0]oct-6-en-3-one and (1S,5R-2-oxabicyclo-[3.3.0]oct-6-en-3-one. The morphology of polyelectrolyte complex beads was characterised by environmental scanning electron microscopy; the spatial distribution of polymers in the beads and cell viability were examined using confocal laser scanning microscopy, and the texture was characterised by the mechanical resistance measurements.

  20. 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

    2017-01-01

    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. PMID:28393911

  1. 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.

  2. Polyacrylamide-grafted-alginate-based pH-sensitive hydrogel beads for delivery of ketoprofen to the intestine: in vitro and in vivo evaluation.

    Science.gov (United States)

    Kulkarni, Raghavendra V; Sa, Biswanath

    2009-01-01

    A pH-sensitive graft co-polymer of polyacrylamide (PAAm) and sodium alginate (SA) was synthesized by free radical polymerization under a nitrogen atmosphere followed by alkaline hydrolysis. The co-polymer was characterized by Fourier transform infrared (FT-IR) spectroscopy, elemental analysis and thermogravimetric analysis (TGA). Ketoprofen-loaded graft co-polymer beads were prepared by ionotropic gelation/covalent cross-linking. The beads were characterized by swelling studies, differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). A pulsatile swelling study indicated that the co-polymer exhibits considerable pH-sensitive behavior. Release of ketoprofen was significantly increased when the pH of the medium was changed from acidic to alkaline. Stomach histopathology of albino rats indicated that the beads were able to retard the release of the drug in the stomach, and gastric side-effects like ulceration, hemorrhage and erosion of gastric mucosa were diminished when the drug was entrapped into PAAm-g-SA-based pH-sensitive hydrogel beads.

  3. 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.

  4. Beads made of α-cyclodextrin and soybean oil: the drying method influences bead properties and drug release.

    Science.gov (United States)

    Hamoudi, M C; Saunier, J; Gueutin, C; Fattal, E; Bochot, A

    2013-09-01

    Freeze-dried beads made of α-cyclodextrin and soybean oil were reported previously as an efficient system for the oral delivery of lipophilic drugs. In the present study, oven-drying was evaluated as another method for drying beads. Oven-drying was optimised and the properties of the resulting beads were assessed. The behavior of oven-dried beads and the release of indomethacin from these beads were evaluated in vitro in simulated gastrointestinal fluids and compared with those of freeze-dried beads. The stability of freeze-dried and oven-dried unloaded beads stored at 25°C for 12 months and at 40°C for 6 months in closed and open vials was also studied by different techniques. An oven-drying time of 6 hours at 25°C was chosen as optimal conditions. Oven-dried beads exhibited a sticky texture making them difficult to handle. They were harder, less fragile and smaller than the freeze-dried ones. The characteristics of oven-dried beads make them more resistant in vitro even in media containing bile salt. The rate of indomethacin release from oven-dried beads was much slower than that from the freeze-dried ones. Whatever the drying method, beads must be stored at room temperature protected from humidity. However, no products of oil degradation were detected with both kinds of beads. This work clearly emphasized that the drying method of the beads had a strong influence on their properties, behavior in simulated gastrointestinal fluids and drug release.

  5. 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.

  6. Phase Diagram Characterization Using Magnetic Beads as Liquid Carriers

    OpenAIRE

    Blumenschein, Nicholas; Han, Daewoo; Steckl, Andrew J.

    2015-01-01

    Magnetic beads with ~1.9 µm average diameter were used to transport microliter volumes of liquids between contiguous liquid segments with a tube for the purpose of investigating phase change of those liquid segments. The magnetic beads were externally controlled using a magnet, allowing for the beads to bridge the air valve between the adjacent liquid segments. A hydrophobic coating was applied to the inner surface of the tube to enhance the separation between two liquid segments. The applied...

  7. Adsorption of CO2 by alginate immobilized zeolite beads

    Science.gov (United States)

    Suratman, A.; Kunarti, E. S.; Aprilita, N. H.; Pamurtya, I. C.

    2017-03-01

    Immobilized zeolit in alginate beads for adsorption of CO2 was developed. Alginate immobilized zeolit beads was generated by dropping the mixture of Na-alginate and zeolite solution into Ca2+ solution. The adsorption efficacy such as the influence of contact time, mass of zeolite, flowrate of CO2, and mass of adsorbent was evaluated. The adsorption of CO2 onto alginate immobilized zeolit beads was investigated by performing both equilibrium and kinetic batch test. Bead was characterized by FTIR and SEM. Alginate immobilized zeolit beads demonstrated significantly higher sorption efficacy compared to plain alginate beads and zeolite with 0.25 mmol CO2 adsorbed /g adsorbent. Optimum condition was achieved with mass composition of alginate:zeolite (3:1), flowrate 50 mL/min for 20 minutes. The alginate immobilized zeolit beads showed that adsorption of CO2 followed Freundlich isotherm and pseudo second order kinetic model. Adsorption of CO2 onto alginate immobilized zeolite beads is a physisorption with adsorption energy of 6.37 kJ/mol. This results indicates that the alginate immobilized zeolit beads can be used as promising adsorbents for CO2.

  8. Characterization of crosslinked polystyrene(PS) beads in SBR matrix

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Yoon-Jong; Choe, Soonja [Inha Univ. (Korea, Republic of)

    1995-12-01

    Monodisperse sized crosslinked polystyrene(PS) beads were prepared by a reaction of semibatch emulsion polymerization with styrene monomer, divinylbenzene(DVB) crosslinking agent and potassium persulfate(K{sub 2}S{sub 2}O{sub 9}) initiator in the absence of emulsifier. The glass transition temperature(T{sub g}) and the mean diameter of the beads were increased from 100{degrees}C to 135{degrees}C and from 402 nm to 532 nm, respectively, for an incorporation of 2 to 10 mol% DVB. Crosslinking density was also linearly increased with DVB content. SEM microphotographs of SBR composite filled with various contents of PS beads revealed that PS beads are relatively well dispersed without changing the spherical shape of the beads in all range of compositions. In stress-strain analysis, elongation at break and tensile strength of SBR composite were increased with the bead content. Applicability of the PS beads as a filler in SBR matrix is tested by plotting Mooney-Rivlin or Guth-Smallwood equations. However, mechanical properties of the composite with the beads were not so excellent as those of the composite with carbon black. Crosslinked PS beads are still tentative as a white color reinforcing filler on SBR matrix.

  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. Ormosil Beads for Insulation of Ground Cryogenic Storage Tanks Project

    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...

  11. Dispersion of fine phosphor particles by newly developed beads mill

    Science.gov (United States)

    Joni, I. Made; Panatarani, C.; Maulana, Dwindra W.

    2016-02-01

    Fine phosphor Y2O3:Eu3+ particles has advanced properties compare to conventional particles applied for compact fluorescent lamp (CFL) as three band phosphor. However, suspension of fine particles easily agglomerated during preparation of spray coating of the CFL tube. Therefore, it is introduced newly developed beads mill system to disperse fine phosphor. The beads mill consist of glass beads, dispersing chamber (impellers), separator chamber, slurry pump and motors. The first important performance of beads mill is the performance of the designed on separating the beads with the suspended fine particles. We report the development of beads mill and its separation performance vary in flow rate and separator rotation speeds. The 27 kg of glass beads with 30 µm in size was poured into dispersing chamber and then water was pumped continuously through the slurry pump. The samples for the separation test was obtained every 1 hours vary in rotation speed and slurry flow rate. The results shows that the separation performance was 99.99 % obtained for the rotation speed of >1000 rpm and flow rate of 8 L/minute. The performances of the system was verified by dispersing fine phosphor Y2O3:Eu3+ particles with concentration 1 wt.%. From the observed size distribution of particles after beads mill, it is concluded that the current design of bead mill effectively dispersed fine phosphor Y2O3:Eu3+.

  12. Non-constrictive bead immobilization leading to decreased and uniform shear stress in microfluidic bead-based ELISA

    CERN Document Server

    Mitra, Kinshuk; Chidambaram, Preethi; Maharry, Aaron P; Xu, Ronald X; Tweedle, Michael F

    2014-01-01

    Microfluidic biosensors have been utilized for sensing a wide range of antigens using numerous configurations. Bead based microfluidic sensors have been a popular modality due to the plug and play nature of analyte choice and the favorable geometry of spherical sensor scaffolds. While constriction of beads against fluid flow remains a popular method to immobilize the sensor, it results in poor fluidic regimes and shear conditions around sensor beads that can affect sensor performance. We present an alternative means of sensor bead immobilization using poly-carbonate membrane. This system results in several orders of magnitude lower variance of flow radially around the sensor bead. Shear stress experienced by our non-constrictive immobilized bead was three orders of magnitude lower. We demonstrate ability to quantitatively sense EpCAM protein, a marker for cancer stem cells and operation under both far-red and green wavelengths with no auto-fluorescence.

  13. 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.

  14. Arming embolic beads with anti-VEGF antibodies and controlling their release using LbL technology.

    Science.gov (United States)

    Sakr, O S; Berndt, S; Carpentier, G; Cuendet, M; Jordan, O; Borchard, G

    2016-02-28

    Transarterial chemoembolization (TACE) is used to treat various types of hypervascular tumors such as hepatocellular carcinoma and renal cancer. However, embolization and blocking of blood vessels nourishing a tumor mass evokes an angiogenic response due to the secretion of vascular endothelial growth factor (VEGF), which results in the formation of new blood vessels and eventually limitation in therapeutic efficacy. The presented work investigates the feasibility of loading the clinically used embolic beads (DC Bead®) with Bevacizumab (BEV), an anti-VEGF antibody, and control its release kinetics via Layer-by-Layer (LbL) coating. This strategy has the aim to achieve high, localized and sustained concentrations of BEV at the tumor site and reduce drug exposure in the systemic circulation. High loading of BEV on lyophilized beads of about 76mg BEV/bead vial was achieved. LbL coating was carried out by depositing alternating layers of the biocompatible polymers alginate and poly-L-lysine. Coating was proven successful by monitoring the reversal of zeta potential after addition of each layer. Morphological changes of the bead surface before and after coating were illustrated using SEM imaging. Moreover, release profiles from different formulations were studied and results showed that optimizing the number of deposited layers effectively slows the release of BEV for three days. Activity of released BEV was studied in different 2D and 3D cell based assays. Released BEV fractions showed comparable activity to fresh BEV solution used as control after 3days. In conclusion, our results suggest the opportunity for loading anti-VEGF antibodies on commercially available embolic beads to increase the efficacy of TACE of hypervascular tumors. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. 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

  16. Statistical approach for assessing the influence of calcium silicate and HPMC on the formulation of novel alfuzosin hydrochloride mucoadhesive-floating beads as gastroretentive drug delivery systems.

    Science.gov (United States)

    Fahmy, Rania Hassan

    2012-09-01

    Multiparticulate floating drug delivery systems have proven potential as controlled-release gastroretentive drug delivery systems that avoid the "all or none" gastric emptying nature of single-unit floating dosage forms. An objective of the presence investigation was to develop calcium silicate (CaSi)/calcium alginate (Ca-Alg)/hydroxypropyl methylcellulose (HPMC) mucoadhesive-floating beads that provide time- and site-specific drug release of alfuzosin hydrochloride (Alf). Beads were prepared by simultaneous internal and external gelation method utilizing 3(2) factorial design as an experimental design; with two main factors evaluated for their influence on the prepared beads; the concentration of CaSi as floating aid (X (1)) and the percentage of HPMC as viscosity enhancer and mucoadhesive polymer (X (2)), each of them was tested in three levels. Developed formulations were evaluated for yield, entrapment efficiency, particle size, surface topography, and buoyancy. Differential scanning calorimetry, Fourier transform infrared spectroscopy, in vitro drug release, as well as in vitro mucoadhesion using rat stomach mucosal membrane were also conducted. Percentage yield and entrapment efficiency ranged from 57.03% to 78.51% and from 49.78% to 83.26%, respectively. Statistical analysis using ANOVA proved that increasing the concentration of either CaSi or HPMC significantly increased the beads yield. Both CaSi and HPMC concentrations were found to significantly affect Alf release from the beads. Additionally, higher CaSi concentration significantly increased the beads diameter while HPMC concentration showed significant positive effect on the beads mucoadhesive properties. CaSi/Ca-Alg/HPMC beads represent simple floating-mucoadhesive gastroretentive system that could be useful in chronopharmacotherapy of benign prostatic hyperplasia.

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

    African Journals Online (AJOL)

    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 technology with a view to identifying where engineering design effort could be directed to ...

  18. 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...

  19. 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...

  20. 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...

  1. 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 ...

  2. In vitro elution of vancomycin from biodegradable osteoconductive calcium phosphate-polycaprolactone composite beads for treatment of osteomyelitis.

    Science.gov (United States)

    Makarov, C; Cohen, V; Raz-Pasteur, A; Gotman, I

    2014-10-01

    In this work, osteoconductive composite materials comprising a large volume fraction of a bioresorbable calcium phosphate ceramic (CaP) and a smaller amount of a polycaprolactone polymer (PCL) were studied as a degradable antibiotic carrier material for treatment of osteomyelitis. Beads loaded with 1 and 4wt.% vancomycin were prepared by admixing dissolved drug to an in situ synthesized dicalcium phosphate (DCP)-PCL or solution-mixed beta-tricalcium phosphate (βTCP)-PCL composite powder followed by high pressure consolidation of the blend at room temperature. Vancomycin release was measured in phosphate-buffered saline (PBS) at 37°C. All the beads gradually released the drug over the period of 4-11weeks, depending on the composite matrix homogeneity and porosity. Mathematical modeling using the Peppas equation showed that vancomycin elution was diffusion controlled. The stability of the antibiotic after high pressure application at room temperature was demonstrated by high-performance liquid chromatography-mass spectrometry (HPLC-MS) studies and MIC testing. The preservation of the structure and activity of vancomycin during the processing of composite beads and its sustained in vitro release profile suggest that high pressure consolidated CaP-PCL beads may be useful in the treatment of chronic bone infections as resorbable delivery vehicles of vancomycin and even of thermally unstable drug substances. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. 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...

  4. Switchable cell trapping using superparamagnetic beads

    Energy Technology Data Exchange (ETDEWEB)

    Bryan, M. T.; Smith, K. H.; Real, M. E.; Bashir, M. A.; Fry, P. W.; Fischer, P.; Im, M.-Y.; Schrefl, T.; Allwood, D. A.; Haycock, J. W.

    2010-04-30

    Ni{sub 81}Fe{sub 19} microwires are investigated as the basis of a switchable template for positioning magnetically-labeled neural Schwann cells. Magnetic transmission X-ray microscopy and micromagnetic modeling show that magnetic domain walls can be created or removed in zigzagged structures by an applied magnetic field. Schwann cells containing superparamagnetic beads are trapped by the field emanating from the domain walls. The design allows Schwann cells to be organized on a surface to form a connected network and then released from the surface if required. As aligned Schwann cells can guide nerve regeneration, this technique is of value for developing glial-neuronal co-culture models in the future treatment of peripheral nerve injuries.

  5. Incorporation of pyrene in polypyrrole/polystyrene magnetic beads.

    Science.gov (United States)

    Głowala, Paulina; Budniak, Adam; Krug, Pamela; Wysocka, Barbara; Berbeć, Sylwia; Dec, Robert; Dołęga, Izabela; Kacprzak, Kamil; Wojciechowski, Jarosław; Kawałko, Jakub; Kępka, Paweł; Kępińska, Daria; Kijewska, Krystyna; Mazur, Maciej

    2014-10-15

    Pyrene, a fluorescent dye, was incorporated into polystyrene particles coated with polypyrrole. The incorporation was achieved by treating the polypyrrole/polystyrene (PPy/PS) beads in a tetrahydrofuran (THF) solution of the pyrene fluorophore followed by rinsing with methanol. The polystyrene cores of the beads swell in THF, allowing penetration of pyrene molecules into the polystyrene structure. The addition of methanol causes contraction of the swollen polystyrene, which encapsulates the dye molecules inside the beads. It is shown that the polypyrrole coating is permeable with respect to both the dye and the solvent, allowing the transport of molecules between the polystyrene cores and the contacting solution. The polypyrrole adlayer can be used as a matrix for the incorporation of magnetic nanoparticles. Embedded particles provide magnetic functionality to the PPy/PS beads. It is demonstrated that the pyrene-loaded beads can be manipulated with an external magnetic field. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Self-organizing magnetic beads for biomedical applications

    CERN Document Server

    Gusenbauer, Markus; Reichel, Franz; Exl, Lukas; Bance, Simon; Ozelt, Harald; Schrefl, Thomas

    2011-01-01

    In the field of biomedicine magnetic beads are used for drug delivery and to treat hyperthermia. Here we propose to use self-organized bead structures to isolate circulating tumor cells using lab-on-chip technologies. Typically blood flows past microposts functionalized with antibodies for circulating tumor cells. Creating these microposts with interacting magnetic beads makes it possible to tune the geometry in size, position and shape. We developed a simulation tool that combines micromagnetics and discrete particle dynamics, in order to design micropost arrays made of interacting beads. The simulation takes into account the viscous drag of the blood flow, magnetostatic interactions between the magnetic beads and gradient forces from external aligned magnets. We developed a particle-particle particle-mesh method for effective computation of the magnetic force and torque acting on the particles.

  7. Biodegradable Polymers

    OpenAIRE

    Isabelle Vroman; Lan Tighzert

    2013-01-01

    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. ...

  8. Fluoride removal using lanthanum incorporated chitosan beads.

    Science.gov (United States)

    Bansiwal, Amit; Thakre, Dilip; Labhshetwar, Nitin; Meshram, Siddharth; Rayalu, Sadhana

    2009-11-01

    Highly selective material based on naturally occurring biomaterial namely chitosan has been designed for the defluoridation of water. Lanthanum incorporated chitosan beads (LCB) were prepared using precipitation method. The synthesis was optimized by varying different synthesis parameters namely lanthanum loading, complexation and precipitation time, strength of ammonia solution used for precipitation, drying time, etc. Lanthanum incorporated chitosan beads were characterized using SEM, FTIR, XRD and EDX. Surface area of LCB was observed to be 2.76 m(2)g(-1). The equilibrium adsorption data fitted well to Langmuir adsorption isotherm and showing maximum fluoride adsorption capacity of 4.7 mg g(-1) with negligible lanthanum release. Kinetic study reveals that adsorption of fluoride is fast and follows pseudo-first-order kinetics. The effect of pH was also studied and the best efficiency was observed at pH 5. Presence of sulphate, nitrate and chloride marginally affected the removal efficiency, however drastic reduction in fluoride uptake was observed in the presence of carbonate and bicarbonate. Negative value of change in free energy (DeltaG degrees) and positive value of change in entropy (DeltaS degrees) suggest the adsorption of fluoride by LCB is feasible and spontaneous process. Positive value of change in enthalpy (DeltaH degrees) suggests the process of fluoride adsorption is endothermic in nature. Regeneration study reveals that 1M ammonium chloride solution appears to be the promising regeneration media showing 81.22% regeneration. The adsorption capacity of LCB was similar in fluoride-contaminated ground water collected from Dhar district of Madhya Pradesh, India, as compared to simulated water.

  9. Molecular Dynamics Simulations of Nanoparticles Coated with Charged Polymers

    Science.gov (United States)

    Wen, Chengyuan; Cheng, Shengfeng

    Polymer coating is frequently used to stabilize colloidal and nano-sized particles. We employ molecular dynamics simulations to study nanoparticles coated with polymer chains that contain ionizable groups. In a polar solvent, the chains become charged with counterions dissociated. In the computational model, we treat the solvent as a uniform dielectric background and use the bead-spring model for the polymer chains. Counterions are explicitly included as mobile beads. The nanoparticle is modeled as a layer of sites uniformly distributed on a spherical surface with a certain fraction of sites serving as the tether points of the grafted polymer brush. We vary the grafting density and calculate the distribution of polymer beads and counterions around the nanoparticle. Our results indicate that charged chains adopt extended conformations because of their mutual repulsions. We further study the interactions between two polymer-coated nanoparticles and obtain the potential of mean force. We also find an interesting transition of a confined single layer of such polymer-coated nanoparticles into two layers when the confinement is removed. Results show that the brush-brush contact has a nonuniform distribution and the nanoparticles tend to form dipole-like structures.

  10. 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

  11. 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

  12. Cetylpyridinium chloride/magnetic alginate beads: an efficient system to remove p-nitrophenol from wastewater

    Science.gov (United States)

    Obeid, Layaly; Bee, Agnes; Talbot, Delphine; Abramson, Sebastien; Welschbillig, Mathias

    2014-05-01

    The adsorption process is one of the most efficient methods to remove pollutants from wastewater provided that suitable adsorbents are used. In order to produce environmentally safe adsorbents, natural polymers have received increasing attention in recent years. Thus, alginate, a polysaccharide extracted from brown seaweeds, is extensively used as inexpensive, non-toxic and efficient biosorbent. Furthermore, it has been shown that the encapsulation of magnetic materials in alginate beads facilitates their recovery from wastewater after the adsorption step, by the use of an external magnetic field gradient, obtained with a magnet or an electromagnet [1, 2]. In the present work, we have studied the adsorption affinity of magnetic alginate beads (called magsorbents)for p-nitrophenol (PNP), used as a hydrophobic pollutant, in presence of cetylpyridinium chloride (CPC), a cationic surfactant. First, the effect of different parameters (pH solution, contact time, surfactant initial concentration…) on the adsorption of CPC on the alginate beads was investigated. Adsorption of the surfactant occurs due to electrostatic attractions between its cationic head groups and negative carboxylate functions of the alginate beads. At larger surfactant concentrations, adsorption is also due to the interaction between the hydrocarbon chains of CPC forming aggregated structures capable of solubilizing hydrophobic solutes. In a second step, we showed that PNP can reach up to 95% of adsorption in the beads in presence of CPC, although the pollutant is poorly adsorbed by alginate in absence of the surfactant. At highest CPC concentrations, desorption occurs as micellar solubilization is preferred over coadsorption. Our magsorbents appear to efficiently remove both cationic surfactant and hydrophobic pollutants and we hope that this fundamental research will be helpful for the future development of magnetically assisted processes in water treatment plants. 1. A.Bee, D.Talbot, S.Abramson, V

  13. Magnetophoretic bead trapping in a high-flowrate biological detection system.

    Energy Technology Data Exchange (ETDEWEB)

    Galambos, Paul C.; Hopkins, Matthew Morgan; Rahimian, Kamayar; Martin, James Ellis; Anderson, G. Ronald; Clem, Paul Gilbert; Rohwer, Lauren Elizabeth Shea; Lemp, Thomas; Derzon, Mark Steven; James, Conrad D.

    2005-03-01

    This report contains the summary of the 'Magnetophoretic Bead Trapping in a High-Flowrate Biological Detection System' LDRD project 74795. The objective of this project is to develop a novel biodetection system for high-throughput sample analysis. The chief application of this system is in detection of very low concentrations of target molecules from a complex liquid solution containing many different constituents--some of which may interfere with identification of the target molecule. The system is also designed to handle air sampling by using an aerosol system (for instance a WESP - Wet Electro-Static Precipitator, or an impact spray system) to get air sample constituents into the liquid volume. The system described herein automatically takes the raw liquid sample, whether air converted or initially liquid matrix, and mixes in magnetic detector beads that capture the targets of interest and then performs the sample cleanup function, allowing increased sensitivity and eliminating most false positives and false negatives at a downstream detector. The surfaces of the beads can be functionalized in a variety of ways in order to maximize the number of targets to be captured and concentrated. Bacteria and viruses are captured using antibodies to surface proteins on bacterial cell walls or viral particle coats. In combination with a cell lysis or PCR (Polymerase Chain Reaction), the beads can be used as a DNA or RNA probe to capture nucleic acid patterns of interest. The sample cleanup capability of this system would allow different raw biological samples, such as blood or saliva to be analyzed for the presence of different infectious agents (e.g. smallpox or SARS). For future studies, we envision functionalizing bead surfaces to bind to chemical weapons agents, radio-isotopes, and explosives. The two main objectives of this project were to explore methods for enhancing the mixing of the capture microspheres in the sample, and to develop a novel high

  14. 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....

  15. Photonic hydrogel beads for controlled release of risedronate

    Science.gov (United States)

    Khajuria, Deepak K.; Roy Mahapatra, D.

    2014-03-01

    pH-sensitive photonic composite hydrogel beads composed of sodium alginate and risedronate sodium (SA/RIS) was prepared crosslinked by Ca2+ owing to the ionic gelation of SA. The structure and surface morphology of the composite hydrogel beads were characterized by SEM. pH-sensitivity of these composite hydrogels beads and the release behaviors of drug from them were investigated. The results showed that the composite hydrogel beads had good pH-sensitivity. The drug loading and encapsulation efficiency were 27.7% and 92% for RIS, respectively. The cumulative release ratios of RIS from the composite hydrogel beads were 2.47% in pH 2.1 solution and 83 % in pH 6.8 solutions within 24 h, respectively. However, the cumulative release ratio of RIS in pH 7.4 solution reached 91% within 7 h. It is proposed that the novel photonic SA/RIS composite hydrogel bead could possess the potential of an increased intestinal absorption and fewer adverse effects of RIS. The pH and salt response of photonic hydrogel bead, as well as the encapsulation of macromolecules, are promising for applications in biomedicine and biotechnology.

  16. Ecohydraulics of Strings and Beads in Bedrock Rivers

    Science.gov (United States)

    Wohl, E.

    2016-12-01

    Twenty years ago, Jack Stanford and others described rivers in bedrock canyons as resembling beads on a string when viewed in planform. The beads are relatively wide, low gradient river segments with floodplains, whereas the strings are the intervening steep, narrow river segments with minimal floodplain development. This pattern of longitudinal variations in channel and valley morphology along bedrock canyon rivers is very common, from small channels to major rivers such as the Colorado. Basic understanding of river ecosystems, as well as limited studies, indicates that the beads are more retentive and biologically productive. Although both strings and beads can provide habitat for diverse organisms, strings are more likely to serve as migration corridors, whereas beads provide spawning and nursery habitat, facilitate lateral (channel-floodplain) and vertical (channel-hyporheic) exchanges and associated habitat diversity, and retain dissolved and particulate organic matter. Recognition of the different characteristics and functions of strings and beads can be used to identify their spatial distribution along a river or within a river network and the hydraulically driven processes that sustain channel form, water quality, and biota within strings and beads. Diverse modeling approaches can then be used to quantify the fluxes of water and sediment needed to maintain these hydraulically driven processes. This conceptual framework is illustrated using examples from mountain streams in the Southern Rockies and canyon rivers in the southwestern United States.

  17. Polymer Nanocomposites

    Indian Academy of Sciences (India)

    The synthesis of polymer nanocomposites is an integral aspect of polymer nanotechnology. By inserting the nano- metric inorganic compounds, the properties of polymers improve and hence this has a lot of applications depending upon the inorganic material present in the polymers. Sol- vent casting is one of the easiest ...

  18. Biodegradable Polymers

    Directory of Open Access Journals (Sweden)

    Isabelle Vroman

    2009-04-01

    Full Text Available 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. The following review presents an overview of the different biodegradable polymers that are currently being used and their properties, as well as new developments in their synthesis and applications.

  19. 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

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

    DEFF Research Database (Denmark)

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

    2007-01-01

    A new hybrid magnetic bead separator that combines an external magnetic field with 175@mm 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....

  1. Formulation and In Vitro evaluation of pH sensitive oil entrapped polymeric blended gellan gum buoyant beads of clarithromycin.

    Science.gov (United States)

    Tripathi, G; Singh, S

    2010-01-01

    A gastroretentive pH sensitive system has been a frontier approach to release the drug in controlled manner in stomach and duodenum. The aim of this study was to develop buoyant beads of gellan based, wherein, the oil was entrapped, blended with hydroxypropyl methyl cellulose or carbopol 934 in order to evaluate its potential for targeted sustained delivery of clarithromycin in the gastric region. Buoyant beads of gellan was developed by inotropic gelation technique using calcium carbonate as gas forming agent and the drug polymer dispersion was emulsified with mineral oil. The oil was entrapped and blended with hydroxypropyl methyl cellulose or carbopol 934. The developed beads were evaluated in terms of diameter,% floating, encapsulation efficiency, In vitro drug release, In vivo gastric residence efficacy and clarithromycine concentration in the mucosa of the experimental animal model. The scanning electron microscope photograph indicated that the prepared beads were spherical in shape and buoyancy, encapsulation efficiency and drug content obtained from all batches were satisfactory. Particle size and percentage buoyancy of the gel beads increased by raising the concentration of calcium carbonate. The formulation exhibited sustained release profile and was best fitted in the Peppas model with n<0.45. Subsequent coating of microbeads exhibited zero-order sustained pattern of the drug release up to 8 hrs. Batch B(4) showed comparatively better residence and the drug concentration in the gastric mucosa of the treated animals. The result provides evidence that the prepared optimized formulation may be used effectively for pH sensitive gastric targeted antibiotic such as clarithromycin.

  2. Formulation and In Vitro evaluation of pH sensitive oil entrapped polymeric blended gellan gum buoyant beads of clarithromycin

    Directory of Open Access Journals (Sweden)

    G Tripathi

    2010-12-01

    Full Text Available "n  "nBackground and the purpose of the study: A gastroretentive pH sensitive system has been a frontier approach to release the drug in controlled manner in stomach and duodenum. The aim of this study was to develop buoyant beads of gellan based, wherein, the oil was entrapped, blended with hydroxypropyl methyl cellulose or carbopol 934 in order to evaluate its potential for targeted sustained delivery of clarithromycin in the gastric region. "nMethods: Buoyant beads of gellan was developed by inotropic gelation technique using calcium carbonate as gas forming agent and the drug polymer dispersion was emulsified with mineral oil. The oil was entrapped and blended with hydroxypropyl methyl cellulose or carbopol 934. The developed beads were evaluated in terms of diameter, % floating, encapsulation efficiency, In vitro drug release, In vivo gastric residence efficacy and clarithromycine concentration in the mucosa of the experimental animal model. "nResults: The scanning electron microscope photograph indicated that the prepared beads were spherical in shape and buoyancy, encapsulation efficiency and drug content obtained from all batches were satisfactory. Particle size and percentage buoyancy of the gel beads increased by raising the concentration of calcium carbonate. The formulation exhibited sustained release profile and was best fitted in the Peppas model with n < 0.45. Subsequent coating of microbeads exhibited zero-order sustained pattern of the drug release up to 8 hrs. Batch B4 showed comparatively better residence and the drug concentration in the gastric mucosa of the treated animals. Conclusion:The result provides evidence that the prepared optimized formulation may be used effectively for pH sensitive gastric targeted antibiotic such as clarithromycin.

  3. 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.

  4. X-ray visible and doxorubicin-loaded beads based on inherently radiopaque poly(lactic acid)-polyurethane for chemoembolization therapy.

    Science.gov (United States)

    Sang, Lin; Luo, Dongdong; Wei, Zhiyong; Qi, Min

    2017-06-01

    The aim of current study was to develop drug-loaded polymeric beads with intrinsic X-ray visibility as embolic agents, targeting for noninvasive intraoperative location and postoperative examination during chemoembolization therapy. To endow polymer with inherent radiopacity, 4,4'-isopropylidinedi-(2,6-diiodophenol) (IBPA) was firstly synthesized and employed as a contrast agent, and then a set of radiopaque iodinated poly(lactic acid)-polyurethanes (I-PLAUs) via chain extender method were synthesized and characterized. These I-PLAU copolymers possessed sufficient radiopacity, in vitro non-cytotoxicity with human adipose-derived stem cells, and in vivo biocompatibility and degradability in rabbit model via intramuscular implantation. Doxorubicin (DOX), as a chemotherapeutic agent, was further incorporated into I-PLAU beads via a double emulsification (W/O/W) method. For drug release, two ratios of DOX-loaded I-PLAU beads exhibited calibrated size (200-550μm), porous internal structure, good X-ray visibility, evenly drug loading as well as tunable drug release. A preliminary test on in vitro tumor cell toxicity demonstrated that the DOX-loaded I-PLAU beads performed efficient anti-tumor effect. This study highlights novel X-ray visible drug-loaded I-PLAU beads used as promising embolic agents for non-invasive in situ X-ray tracking and efficient chemotherapy, which could bring opportunities to the next generation of multifunctional embolic agents. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Guided self-assembly of magnetic beads for biomedical applications

    CERN Document Server

    Gusenbauer, Markus; Reichel, Franz; Exl, Lukas; Bance, Simon; Fischbacher, Johann; Özelt, Harald; Kovacs, Alexander; Brandl, Martin; Schrefl, Thomas

    2013-01-01

    Micromagnetic beads are widely used in biomedical applications for cell separation, drug delivery, and hypothermia cancer treatment. Here we propose to use self-organized magnetic bead structures which accumulate on fixed magnetic seeding points to isolate circulating tumor cells. The analysis of circulating tumor cells is an emerging tool for cancer biology research and clinical cancer management including the detection, diagnosis and monitoring of cancer. Microfluidic chips for isolating circulating tumor cells use either affinity, size or density capturing methods. We combine multiphysics simulation techniques to understand the microscopic behavior of magnetic beads interacting with Nickel accumulation points used in lab-on-chip technologies. Our proposed chip technology offers the possibility to combine affinity and size capturing with special antibody-coated bead arrangements using a magnetic gradient field created by Neodymium Iron Boron permanent magnets. The multiscale simulation environment combines ...

  6. More About Cutting Tool For Shaving Weld Beads

    Science.gov (United States)

    Oelgoetz, Peter A.; Davis, William M.

    1996-01-01

    Report describes modification and testing of proposed tool discussed in "Cutting Tool For Shaving Weld Beads" (MFS-30056). Modified version of commercial pneumatically driven rotary cutting tool removes such hard metals as nickel alloys, titanium, and stainless steels.

  7. Magnetic Latex Beads Chaining on a Spherical Interface

    Science.gov (United States)

    McGorty, R. J.; Dinsmore, A. D.

    2004-03-01

    We study chain formation of magnetic beads confined on a curved interface. Using an inverted light microscope, we observe how micron-sized superparamagnetic latex beads behave on the interface of toluene droplets in water with an external magnetic field. We observe the beads attracting one another where the interface is parallel to the external field but repelling one another where the interface is perpendicular. At some given angle between the external field and interface the chain length stops increasing, regardless of field strength or droplet size. A detailed understanding of such chain formations may provide the ability to coat droplets with beads arranged in interesting patterns or create chains with a controllable curvature and length. This work is supported by the UMass Faculty Research Grant program.

  8. Chromatography modelling to describe protein adsorption at bead level.

    Science.gov (United States)

    Gerontas, Spyridon; Shapiro, Michael S; Bracewell, Daniel G

    2013-04-05

    Chromatographic modelling can be used to describe and further understand the behaviour of biological species during their chromatography separation on adsorption resins. Current modelling approaches assume uniform rate parameters throughout the column. Software and hardware advances now allow us to consider what can be learnt from modelling at bead level, enabling simulation of heterogeneity in bead and packed bed structure due to design or due to changes during operation. In this paper, a model has been developed to simulate at bead level protein loading in 1.5 μl microfluidic columns. This model takes into account the heterogeneity in bead sizes and the spatial variations of the characteristics of a packed bed, such as bed void fraction and dispersion, thus offering a detailed description of the flow field and mass transfer phenomena. Simulations were shown to be in good agreement with published experimental data. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. 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.

  10. 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

  11. Adsorption Capacity of Chitosan Beads in Toxic Solutions

    OpenAIRE

    P. Setthamongkol; J. Salaenoi

    2012-01-01

    The efficiency of chitosan beads processed from 4 marine animal shells; white leg shrimp (Litopenaeus vannamei), mud crab (Scylla sp.), horseshoe crab (Carcinoscorpius rotundicauda), and cuttlefish bone (Sepia sp.), for the adsorption experiments of ammonia and formaldehyde were investigated. The porosities of chitosan from the shells looked like beads were distinctly examined under SEM. The original pores of those shells on the surface areas compose of evenly fine pores....

  12. Ferrite bead effect on Class-D amplifier audio quality

    OpenAIRE

    Haddad, Kevin El; Mrad, Roberto; Morel, Florent; Pillonnet, Gael; Vollaire, Christian; Nagari, Angelo

    2014-01-01

    International audience; This paper studies the effect of ferrite beads on the audio quality of Class-D audio amplifiers. This latter is a switch-ing circuit which creates high frequency harmonics. Generally, a filter is used at the amplifier output for the sake of electro-magnetic compatibility (EMC). So often, in integrated solutions, this filter contains ferrite beads which are magnetic components and present nonlinear behavior. Time domain measurements and their equivalence in frequency do...

  13. Optimization of polyphenol oxidase immobilization in copper alginate beads.

    Science.gov (United States)

    Kocaturk, Selin; Yagar, Hulya

    2010-05-01

    Polyphenol oxidase (PPO, EC 1.14.18.1) was isolated from artichoke head (Cynara scolymus L.) by using 0.1 M Tris-HCl buffer (pH 7.0), concentrated by (NH4)2SO4 precipitation, and immobilized in copper-alginate beads. Immobilization yield was determined to be 70%. The cresolase and catecholase activities of enzyme immobilized at optimum immobilization conditions were found to be 13.3 and 670 U g beads min(-1), respectively. Effects of immobilization conditions such as alginate concentration, CaCl2 concentration, amount of loading enzyme, bead size, and amount of beads on enzymatic activity were investigated. Optimum alginate and CuCl2 concentration were found to be 2 % and 3 % (w/v), respectively. Using bead (diameter 3 mm) amount of 0.25 g maximum enzyme activities were observed for both polyphenol activities. The initial concentrations of loading free enzyme were 6.5 U mL(-1) and 5815 U mL(-1) for cresolase activity and catecholase activities, respectively. Beads prepared at optimum immobilization conditions were suitable for up to 8 repeated uses.

  14. The influence of process variables of preparation of oxycellulose beads on their dissolution profile.

    Science.gov (United States)

    Bajerová, Martina; Muselík, Jan; Gajdziok, Jan; Masteiková, Ruta; Dvorácková, Katerina

    2013-01-01

    Particles preparation from biodegradable polymers as carriers for the controlled release of drugs has been the focus of many investigations and the subject of a growing field of research in recent years. The aim of this study was to develop and optimize the preparation of oxycellulose beads containing diclofenac sodium as a model drug. Particle size, surface, drug content and encapsulation efficiency were evaluated, drug dissolution profiles were measured and drug release mechanism estimated. The prepared oxycellulose beads were uniform in size with encapsulation efficiency ranging from 53.2 to 74.9%. The lower temperature of the crosslinking solution and its saturation with diclofenac sodium increased the encapsulation efficiency, especially when both parameters were combined. The application of ultrasound had a negative effect on drug encapsulation. The dissolution of diclofenac sodium in pH 1.2 was close to zero as its solubility in this medium is very limited. The drug release in pH 6.8 lasted from 10 to 16 h showing biphasic behavior with a significant lag time. T1/2 decreased with increasing encapsulation efficiency and ultrasound application. Diclofenac sodium was released from the prepared oxycellulose particles by diffusion as well as by erosion process; ahigh correlation was found with zero order kinetics.

  15. Carboxymethyl fenugreek galactomannan-gellan gum-calcium silicate composite beads for glimepiride delivery.

    Science.gov (United States)

    Bera, Hriday; Mothe, Srilatha; Maiti, Sabyasachi; Vanga, Sridhar

    2017-09-13

    Novel carboxymethyl fenugreek galactomannan (CFG)-gellan gum (GG)-calcium silicate (CS) composite beads were developed for controlled glimepiride (GLI) delivery. CFG having degree of carboxymethylation of 0.71 was synthesized and characterized by FTIR, DSC and XRD analyses. Subsequently, GLI-loaded hybrids were accomplished by ionotropic gelation technique employing Ca+2/Zn+2/Al+3 ions as cross-linkers. All the formulations demonstrated excellent drug encapsulation efficiency (DEE, 48-97%) and sustained drug release behaviour (Q8h, 62-94%). These quality attributes were remarkably influenced by polymer-blend (GG:CFG) ratios, cross-linker types and CS inclusion. The drug release profile of the optimized formulation (F-6) was best fitted in zero-order model with anomalous diffusion driven mechanism. It also conferred excellent ex vivo mucoadhesive property and considerable hypoglycemic effect in streptozotocin-induced diabetic rats. Furthermore, the beads were characterized for drug-excipients compatibility, drug crystallinity, thermal behaviour and surface morphology. Thus, the developed hybrid matrices are appropriate for controlled delivery of GLI for Type 2 diabetes management. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Nanosized amine-rich spheres embedded polymeric beads for Cr (VI) removal.

    Science.gov (United States)

    Lin, Peng; Liu, Chao; Li, Jiansheng; Qi, Junwen; Luo, Rui; Sun, Xiuyun; Shen, Jinyou; Han, Weiqing; Wang, Lianjun

    2017-12-15

    Porous matrix immobilization is considered as an effective approach to address the engineering challenges during practical application of nanoadsorbent. In this work, polyethersulfone (PES) beads with diameter of around 2.5mm, in which nanosized amine-rich polymer spheres (APSs) with particle size of ∼400nm are immobilized, are fabricated via phase inversion route. APSs-PES beads possess asymmetric and hierarchical structure with an exterior porous surface dense layer and numerous inner interpenetrating fingerlike channels, which promote the transportation of molecule and prevent the leaching of nanoadsorbents. The well distributed APSs with nitrogen-containing functional groups provide abundant adsorption sites. The cooperative attributing of the hierarchical structure and APSs demmonstrates enhanced Cr (VI) adsorption efficiency. The adsorption capacity of Cr (VI) is 243.9mg/g at 298K by Langmuir fitting. The effects of pH, temperature, the ratio of adsorbents and coexisting ionic are further studied in detail. The Cr (VI) removal mechanism is further explored by the combination of SEM, XPS, FTIR measurements and the adsorption parameters, further revealing the synergistic contribution of electrostatic attraction and reduction process. Therefore, this kind of adsorbents may show promising prospects on elimination of hazardous Cr (VI) in wastewater treatment. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Bead Capture and Release on a Magnetic Sensor in a Microfluidic System

    DEFF Research Database (Denmark)

    Dalslet, Bjarke Thomas; Damsgaard, Christian Danvad; Freitas, S.C.

    Planar Hall effect magnetic sensors for detection of biological agents using surface treated magnetic beads are integrated with a fluid injection system. The response of the sensors is used to evaluate bead capture rates for different bead concentrations c and fluid flow rates Q, and to monitor...... to capture of beads by the magnetic fields near the sensor. It is shown that beads can be washed off the sensor surface....

  18. 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

  19. 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.

  20. 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

  1. 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.

  2. Phase Diagram Characterization Using Magnetic Beads as Liquid Carriers.

    Science.gov (United States)

    Blumenschein, Nicholas; Han, Daewoo; Steckl, Andrew J

    2015-09-04

    Magnetic beads with ~1.9 µm average diameter were used to transport microliter volumes of liquids between contiguous liquid segments with a tube for the purpose of investigating phase change of those liquid segments. The magnetic beads were externally controlled using a magnet, allowing for the beads to bridge the air valve between the adjacent liquid segments. A hydrophobic coating was applied to the inner surface of the tube to enhance the separation between two liquid segments. The applied magnetic field formed an aggregate cluster of magnetic beads, capturing a certain liquid amount within the cluster that is referred to as carry-over volume. A fluorescent dye was added to one liquid segment, followed by a series of liquid transfers, which then changed the fluorescence intensity in the neighboring liquid segment. Based on the numerical analysis of the measured fluorescence intensity change, the carry-over volume per mass of magnetic beads has been found to be ~2 to 3 µl/mg. This small amount of liquid allowed for the use of comparatively small liquid segments of a couple hundred microliters, enhancing the feasibility of the device for a lab-in-tube approach. This technique of applying small compositional variation in a liquid volume was applied to analyzing the binary phase diagram between water and the surfactant C12E5 (pentaethylene glycol monododecyl ether), leading to quicker analysis with smaller sample volumes than conventional methods.

  3. 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.

  4. Removal of uranium from aqueous solution by aliginate beads

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Jing; Wang, Jian Long [Collaborative Innovation Center for Advanced Nuclear Energy Technology, INET, Tsinghua University, Beijing (China); Jiang, Yizhou [Northwest Institute of Nuclear Technology, Xian (China)

    2017-04-15

    The adsorption of uranium (VI) by calcium alginate beads was examined by batch experiments. The effects of environmental conditions on U (VI) adsorption were studied, including contact time, pH, initial concentration of U (VI), and temperature. The alginate beads were characterized by using scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. Fourier transform infrared spectra indicated that hydroxyl and alkoxy groups are present at the surface of the beads. The experimental results showed that the adsorption of U (VI) by alginate beads was strongly dependent on pH, the adsorption increased at pH 3∼7, then decreased at pH 7∼9. The adsorption reached equilibrium within 2 minutes. The adsorption kinetics of U (VI) onto alginate beads can be described by a pseudo first-order kinetic model. The adsorption isotherm can be described by the Redlich-Peterson model, and the maximum adsorption capacity was 237.15 mg/g. The sorption process is spontaneous and has an exothermic reaction.

  5. Removal of Uranium from Aqueous Solution by Alginate Beads

    Directory of Open Access Journals (Sweden)

    Jing Yu

    2017-04-01

    Full Text Available The adsorption of uranium (VI by calcium alginate beads was examined by batch experiments. The effects of environmental conditions on U (VI adsorption were studied, including contact time, pH, initial concentration of U (VI, and temperature. The alginate beads were characterized by using scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. Fourier transform infrared spectra indicated that hydroxyl and alkoxy groups are present at the surface of the beads. The experimental results showed that the adsorption of U (VI by alginate beads was strongly dependent on pH, the adsorption increased at pH 3∼7, then decreased at pH 7∼9. The adsorption reached equilibrium within 2 minutes. The adsorption kinetics of U (VI onto alginate beads can be described by a pseudo first-order kinetic model. The adsorption isotherm can be described by the Redlich-Peterson model, and the maximum adsorption capacity was 237.15 mg/g. The sorption process is spontaneous and has an exothermic reaction.

  6. Weld bead profile of laser welding dissimilar joints stainless steel

    Science.gov (United States)

    Mohammed, Ghusoon R.; Ishak, M.; Aqida, S. N.; Abdulhadi, Hassan A.

    2017-10-01

    During the process of laser welding, the material consecutively melts and solidifies by a laser beam with a peak high power. Several parameters such as the laser energy, pulse frequency, pulse duration, welding power and welding speed govern the mode of the welding process. The aim of this paper is to investigate the effect of peak power, incident angle, and welding speed on the weld bead geometry. The first investigation in this context was conducted using 2205-316L stainless steel plates through the varying of the welding speed from 1.3 mm/s to 2.1 mm/s. The second investigation was conducted by varying the peak power from 1100 W to 1500 W. From the results of the experiments, the welding speed and laser power had a significant effect on the geometry of the weld bead, and the variation in the diameter of the bead pulse-size. Due to the decrease in the heat input, welding speed affected penetration depth more than bead width, and a narrow width of heat affected zone was achieved ranging from 0.2 to 0.5 mm. Conclusively, weld bead geometry dimensions increase as a function of peak power; at over 1350 W peak power, the dimensions lie within 30 μm.

  7. Supramolecular Polymers

    Science.gov (United States)

    Stupp, S. I.; Keser, M.; Huggins, K. E.; Tew, G.; Li, L. S.; Whitaker, C.

    1997-03-01

    An interesting target in polymer science is to find pathways to highly regular supramolecular units with dimensions similar to those of high molar mass linear or hyperbranched polymers. These units lack a polymeric backbone but could serve as precursors to shape invariant covalent polymers analogous to folded proteins. We are pursuing access to these polymers with designed molecules programmed to assemble into nanostructures of regular shape and dimension. We have discovered systems of miniaturized triblock copolymers that yield supramolecular polymers. These supramolecular polymers are shaped as mushroom nanostructures, and form materials with interesting surface and optical properties. Molecular modeling indicates that a balance of aggregation and hard core repulsive forces among structural units may be responsible for the formation of these supramolecular polymers.

  8. Evaluation of pH-sensitivity and drug release characteristics of (polyacrylamide-grafted-xanthan)-carboxymethyl cellulose-based pH-sensitive interpenetrating network hydrogel beads.

    Science.gov (United States)

    Kulkarni, Raghavendra V; Sa, Biswanath

    2008-12-01

    Novel pH-sensitive interpenetrating network hydrogel beads of polyacrylamide-grafted-xanthan (PAAm-g-XG) and sodium carboxymethyl cellulose (NaCMC) loaded with ketoprofen were prepared and evaluated for pH sensitivity and drug release characteristics. The pH-sensitive PAAm-g-XG copolymer was synthesized by free radical polymerization under the nitrogen atmosphere followed by alkaline hydrolysis. The grafting and alkaline hydrolysis reactions were confirmed by Fourier transform infrared spectroscopy. Differential scanning calorimetry and X-ray diffraction studies were carried out to know the crystalline nature of encapsulated drug. Scanning electron microscopic study revealed that the interpenetrating polymer network (IPN) beads possess porous matrix structure in alkaline pH whereas nonporous matrix structure was observed in acidic pH. The swelling of the beads and drug release was significantly increased when pH of the medium was changed from acidic to alkaline. The results of pulsatile swelling study indicated that the IPN beads changed their swelling behavior when pH of the external medium was altered. As pH of the medium was changed from 1.2 to 7.4, a considerable increase in swelling was observed for all the beads. However, swelling process was slower than the deswelling. At higher pH values, the carboxyl functional groups of hydrogels undergo ionization and the osmotic pressure inside the beads increases resulting in higher swelling. Drug release followed case II transport mechanism in acidic medium whereas anomalous/non-Fickian transport mechanism was observed in alkaline medium.

  9. Nanostructured polymer-titanium composites and titanium oxide through polymer swelling in titania precursor.

    Science.gov (United States)

    Kierys, A; Zaleski, R; Buda, W; Pikus, S; Dziadosz, M; Goworek, J

    2013-06-01

    Polymer (XAD7HP)/Ti(4+) nanocomposites were prepared through the swelling of polymer in titanium (IV) ethoxide as a titanium dioxide precursor. The nanocomposite beads exhibit relatively high porosity different than the porosity of the initial polymer. Thermal treatment of composite particles up to 200 °C in vacuum causes the change of their internal structure. At higher temperature, the components of composite become more tightly packed. Calcination at 600 °C and total removal of polymer produce spherically shaped TiO2 condensed phase as determined by XRD. Thermally treated composites show the substantial change of pore dimensions within micro- and mesopores. The presence of micropores and their transformation during thermal processing was studied successfully by positron annihilation lifetime spectroscopy (PALS). The results derived from PALS experiment were compared with those obtaining from low-temperature nitrogen adsorption data.

  10. A Pneumatic Actuated Microfluidic Beads-Trapping Device

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Guocheng; Cai, Ziliang; Wang, Jun; Wang, Wanjun; Lin, Yuehe

    2011-08-20

    The development of a polydimethylsiloxane (PDMS) microfluidic microbeads trapping device is reported in this paper. Besides fluid channels, the proposed device includes a pneumatic control chamber and a beads-trapping chamber with a filter array structure. The pneumatic flow control chamber and the beads-trapping chamber are vertically stacked and separated by a thin membrane. By adjusting the pressure in the pneumatic control chamber, the membrane can either be pushed against the filter array to set the device in trapping mode or be released to set the device in releasing mode. In this paper, a computational fluid dynamics simulation was conducted to optimize the geometry design of the filter array structure; the device fabrication was also carried out. The prototype device was tested and the preliminary experimental results showed that it can be used as a beads-trapping unit for various biochemistry and analytical chemistry applications, especially for flow injection analysis systems.

  11. Magnet polepiece design for uniform magnetic force on superparamagnetic beads.

    Science.gov (United States)

    Fallesen, Todd; Hill, David B; Steen, Matthew; Macosko, Jed C; Bonin, Keith; Holzwarth, George

    2010-07-01

    Here we report construction of a simple electromagnet with novel polepieces which apply a spatially uniform force to superparamagnetic beads in an optical microscope. The wedge-shaped gap was designed to keep partial differential B(x)/ partial differential y constant and B large enough to saturate the bead. We achieved fields of 300-600 mT and constant gradients of 67 T/m over a sample space of 0.5x4 mm(2) in the focal plane of the microscope and 0.05 mm along the microscope optic axis. Within this space the maximum force on a 2.8 microm diameter Dynabead was 12 pN with a spatial variation of approximately 10%. Use of the magnet in a biophysical experiment is illustrated by showing that gliding microtubules propelled by the molecular motor kinesin can be stopped by the force of an attached magnetic bead.

  12. Damped bead on a rotating circular hoop - a bifurcation zoo

    CERN Document Server

    Dutta, Shovan

    2012-01-01

    The evergreen problem of a bead on a rotating hoop shows a multitude of bifurcations when the bead moves with friction. This motion is studied for different values of the damping coefficient and rotational speeds of the hoop. Phase portraits and trajectories corresponding to all different modes of motion of the bead are presented. They illustrate the rich dynamics associated with this simple system. For some range of values of the damping coefficient and rotational speeds of the hoop, linear stability analysis of the equilibrium points is inadequate to classify their nature. A technique involving transformation of coordinates and order of magnitude arguments is presented to examine such cases. This may provide a general framework to investigate other complex systems.

  13. Extended release of vitamins from magnetite loaded polyanionic polymeric beads.

    Science.gov (United States)

    Sonmez, Maria; Verisan, Cristina; Voicu, Georgeta; Ficai, Denisa; Ficai, Anton; Oprea, Alexandra Elena; Vlad, Mihaela; Andronescu, Ecaterina

    2016-08-30

    Here we explore a novel approach of increasing the release duration of folic and ascorbic acid from magnetite entrapped into calcium-alginate beads. Synthesis and characterization of magnetite-vitamins complexes are reported. The magnetite-vitamins complexes were characterized by FT-IR, XRD, SEM, BET and DTA-TG. Also calcium-alginate magnetic beads were prepared by dripping a mixture of sodium alginate with magnetite-vitamins complexes into calcium chloride solution. Extended release profile of the two experimental models was evaluated and quantified by UV-vis. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Visual DNA -- identification of DNA sequence variations by bead trapping.

    Science.gov (United States)

    Ståhl, Patrik L; Gantelius, Jesper; Natanaelsson, Christian; Ahmadian, Afshin; Andersson-Svahn, Helene; Lundeberg, Joakim

    2007-12-01

    In this paper we describe a method that uses the nearly covalent strength biotin-streptavidin interaction to attach a paramagnetic bead of micrometer size to a DNA molecule of nanometer size, scaling up the spatial size of a query DNA strand by a factor of 1000, making it visible to the human eye. The use of magnetic principles enables rapid binding and washing of detector beads, facilitating a readout of amplified DNA sequences in a few minutes. Here we exemplify the method on mitochondrial DNA variations using an array platform. Visual identification and documentation can be performed with an ordinary mobile phone equipped with a built-in camera.

  15. 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.

  16. 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.

  17. 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.

  18. Flow in a double-film-fed fluid bead between contra-rotating rolls, Part 2: bead break and flooding

    OpenAIRE

    Gostling, M.J.; Savage, M.D.; Wilson, M.C.T.

    2001-01-01

    Two-dimensional flow is considered in a fluid bead located in the gap between a pair of contra-rotating cylinders and bounded by two curved menisci. The stability of such bead flows with two inlet films, and hence no contact line, are analysed as the roll speed ratio S is increased. One of the inlet films can be regarded as an ‘input flux’ whilst the other is a ‘returning film’ whose thickness is specified as a fraction [zeta] of the outlet film on that roll. The flow is modelled via lubricat...

  19. Development and optimization of modified release IPN macromolecules of oxcarbazepine using natural polymers.

    Science.gov (United States)

    Prajapati, Vipul D; Gandhi, Abhishek K; Patel, Krishna K; Patel, Bhumit N; Chaudhari, Anita M; Jani, Girish K

    2015-02-01

    The study shows development and optimization of modified release interpenetrating polymer network (IPN) macromolecules (beads) of oxcarbazepine using sodium alginate-egg albumin prepared by ionotropic gelation method and CaCl2 as a cross-linker. Independent variables were identified based on preliminary study of investigation. The effect of amount of both polymers on drug entrapment efficiency (DEE,%), bead size (μm) and cumulative drug release at 8 h (Q8h, %) were optimized using 3(2) factorial design. The DEE, average size and Q8h were found in the range of 65.08-91.02%, 976-1084 μm and 73.50-94.06% respectively. The beads were also characterized by FTIR, DSC, SEM and XRD. The experiential responses were coincided well with predicted values obtained by Design-Expert(®) 8.0.6.1 software. The swelling of beads were influenced by the pH of a release medium. The in vitro drug release from IPN beads exhibited sustained release Hixson-Crowell pattern with anomalous non-Fickian diffusion mechanism concluding that the developed sodium alginate-egg albumin IPN composite beads are suitable for sustained delivery of oxcarbazepine for desired period. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. 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 ...

  1. Multifunctional cellulose beads and their interaction with gram positive bacteria.

    Science.gov (United States)

    Blachechen, Leandro S; Fardim, Pedro; Petri, Denise F S

    2014-09-08

    Cellulose beads with ∼3 mm of diameter and high circularity were obtained by dripping cellulose solutions (5, 6, and 7 wt %) dissolved in NaOH7%/urea12%, into HCl 2 M coagulation bath. Carboxylic groups were generated on beads surface through NaClO/NaClO2/TEMPO oxidation method, achieving total charge density of ∼0.77 mmol/g. Pristine (CB) and oxidized (OCB) beads were characterized by means of optical images analyses, scanning electron microscopy (SEM) and compression tests. Both types of beads, CB and OCB, were used as adsorbent for poly(4-vinyl-N-pentylpyridinium) bromide, QPVP-C5, a bactericidal agent. The adsorption of QPVP-C5 on CB and OCB was evaluated by means of FTIR-ATR, UV-vis, CHN elemental analyses, and X-ray photoelectron spectroscopy (XPS). The adsorbed amount of QPVP-C5 was remarkably higher on OCB than on CB due to ionic interactions. Desorption was less than 5%. The interaction between neat OCB or OCB coated and two different amounts of QPVP-C5 and Gram-positive bacteria Micrococcus luteus was assessed by changes in turbidimetry, SEM, and elemental analyses. Bacteria adsorbed on the surface of neat OCB and weakly QPVP-C5 coated OCB due to hydrogen bonding or ion-dipole interaction. Notorious bactericidal action was observed for OCB samples coated with large amount of QPVP-C5.

  2. Removal of organic dyes by magnetic alginate beads.

    Science.gov (United States)

    Rocher, Vincent; Siaugue, Jean-Michel; Cabuil, Valérie; Bee, Agnès

    2008-02-01

    This study deals with the development of a clean and safe process for water pollution remediation. We have synthesized a magnetic adsorbent in order to develop a solid-phase extraction process assisted by a magnetic field. To follow an 'ecoconception' approach, magnetic beads containing magnetic nanoparticles and activated carbon are prepared with a biopolymer extracted from algae, sodium alginate. The use of renewable bioresources of low cost and those disposable in large amount allows the development of a product with a low impact on the environment. The adsorption properties of activated carbon and magnetic properties of iron oxide nanoparticles are combined to produce an interesting magnetic composite. Synthesis and characterization of the magnetic beads have been reported. Their adsorption capacity was investigated by measuring the removal of two dyes (methylene blue and methyl orange) of different charges from aqueous solutions. The efficiency of the beads has been compared with that of non-encapsulated activated carbon. The effects of initial dye concentration, pH and calcium content of the beads have been studied. Adsorption kinetics experiments have been carried out and the data have been well fitted by a pseudo-second-order equation.

  3. 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 ...

  4. USE OF ANTIBIOTIC CEMENT SPACERS/BEADS IN TREATMENT ...

    African Journals Online (AJOL)

    of the antibiotic cement spacers or beads. Vancomycin was added to the bone cement because it is a heat stable antibiotic. Most patients with chronic musculoskeletal infections in our set up would have received gentamycin at some point during their treatment and thus use of vancomycin as the alternative was considered.

  5. Magnetic manipulation and sensing of beads for bioapplications

    DEFF Research Database (Denmark)

    Henriksen, Anders Dahl

    magnetic stack. The permalloy micro stripes created a spatially varying magnetic field, which in combination with a rotating external field was used to transport magnetic beads from stripe to stripe. Systematic measurements of the magnetophoresis properties on varying stripe geometries were performed...

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

    African Journals Online (AJOL)

    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 aesthetics and criticism to complement their form of art for a better livelihood and diversification in jewellery. There are ...

  7. exploring traditional glass bead making techniques in jewellery

    African Journals Online (AJOL)

    User

    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 aesthetics and criticism to complement their form of art for a better livelihood and diversification in ...

  8. Glass bead transformation method for gram-positive bacteria

    OpenAIRE

    Pongsak Rattanachaikunsopon; Parichat Phumkhachorn

    2009-01-01

    A simple, inexpensive and reproducible transformation method was developed for Gram-positive bacteria. It was based on agitation of bacterial protoplasts with glass beads in the presence of DNA and polyethylene glycol. By using this method, introduction of pGK12 into protoplasts of several strains of Gram-positive bacteria was achieved.

  9. 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.

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

    African Journals Online (AJOL)

    user

    Abstract. 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.

  11. Highly Porous Core-Shell Structured Graphene-Chitosan Beads.

    Science.gov (United States)

    Ouyang, An; Wang, Chunhui; Wu, Shiting; Shi, Enzheng; Zhao, Wenqi; Cao, Anyuan; Wu, Dehai

    2015-07-08

    Graphene oxide (GO) sheets have been assembled into various three-dimensional porous structures and composites, with potential applications in energy and environmental areas. Here, we show the combination of GO and chitosan (CTS) into inorganic-organic heterocomposites as ∼3 mm diameter core-shell beads with controlled microstructure. The spherical GO-CTS beads, made by a two-step freeze-casting method, consist of a GO core wrapped by a CTS shell with abrupt interface; both parts have high porosities (94-96%) and mesopores volume (0.246 cm(3)/g) yet with different pore morphologies. Incorporation of a GO core into the CTS beads significantly improved the methyl orange adsorption capacity (353 mg/g at 318 K) compared with pure CTS beads. Key factors such as the pH value, adsorbent dosage, concentration, time, and temperature have been studied in detail, whereas adsorption isotherm and kinetic studies reveal a Langmuir model following the pseudo-second order.

  12. 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 ...

  13. [Primary cancellous bone formation around micro-chambered beads].

    Science.gov (United States)

    Draenert, M E; Draenert, Y; Draenert, K; Pohlemann, T; Erler, M

    2014-01-01

    The question has been raised whether benign bone defects in patients can be treated with bone forming osteoconductive ceramics achieving primarily a cancellous bone scaffold, which is under load from the beginning. Ten reconstructions were performed in 9patients (6women and 3male), with a mean age of 49 (25-65)years, suffering a high variety of epi- and metaphyseal defects, four tibial fractures, two calcaneal fractures, one pathological phalangeal fracture, one chondroma of the distal femur and two open-wedge osteotomies were filled with micro-chambered ceramic beads of 4 and 6mm in diameter. The mean follow up was 22 (7- 8)months. X-rays and CT-scans formed the basis for the evaluation of the reconstruction of the cancellous bone scaffolds. All cancellous structures were rebuilt, if completely filled with bone-forming elements. If the filling was incomplete, no physiological cancellous bone scaffold resulted. The β-TCP micro-chambered beads were completely reabsorbed or sandwich-like incorporated at the time of evaluation. The HA micro-chambered beads revealed a contrast enhancement and were integrated in the osseous construction of the bone scaffold. Primary cancellous bone formation can be achieved with osteoconductive ceramic micro-chambered beads and can be combined with any osteosynthesis for stable fixation. Copyright © 2013 SECOT. Published by Elsevier Espana. All rights reserved.

  14. EXFOLIATION AT WIRE TWISTING FOR TIRES BEAD RINGS

    Directory of Open Access Journals (Sweden)

    A. N. Savenok

    2010-01-01

    Full Text Available It is shown that reduction of twisting numbers up to destruction of cold drawn wire for bead rings is stipulated by junction of microcracks formed in longitudinallyand transverse-oriented planes of deformation shift with creation of main crack.

  15. PENGARUH PENAMBAHAN TRIPOLYFOSFAT PADA KITOSAN BEADS UNTUK ADSORPSI METHYL ORANGE

    OpenAIRE

    ADR Madjid; M Nitsae; Atikah Atikah; A Sabarudin

    2016-01-01

    Modifikasi kitosan dilakukan dalam rangka meningkatkan daya adsorpsi kitosan. Penambahan tripolyfosfat (TPP) dapat mempengaruhi kinerja kitosan untuk mengadsorpsi methyl orange. Penambahan cross-linker epiklorohidrin (ECH) bertujuan untuk meningkatkan stabilitas kimianya dalam kondisi asam serta membentuk pori kitosan beads lebih besar. Penelitian ini bertujuan untuk mengetahui konsentrasi dan lama perendaman TPP optimum pada adsorpsi methyl orange oleh kitosan. Konsentrasi TPP (1%, 5%, 10% d...

  16. Residual gentamicin-release from antibiotic-loaded polymethylmethacrylate beads after 5 years of implantation

    NARCIS (Netherlands)

    Neut, D; van de Belt, H; van Horn, [No Value; van der Mei, HC; Busscher, HJ

    In infected joint arthroplasty, high local levels of antibiotics are achieved through temporary implantation of non-biodegradable gentamicin-loaded polymethylmethacrylate beads. Despite their antibiotic release, these beads act as a biomaterial surface to which bacteria preferentially adhere, grow

  17. Quantum-dot-tagged photonic crystal beads for multiplex detection of tumor markers.

    Science.gov (United States)

    Li, Juan; Wang, Huan; Dong, Shujun; Zhu, Peizhi; Diao, Guowang; Yang, Zhanjun

    2014-12-04

    Novel quantum-dot-tagged photonic crystal beads were fabricated for multiplex detection of tumor markers via self-assembly of quantum dot-embedded polystyrene nanospheres into photonic crystal beads through a microfluidic device.

  18. Branched polymers on branched polymers

    OpenAIRE

    Durhuus, Bergfinnur; Jonsson, Thordur

    1996-01-01

    We study an ensemble of branched polymers which are embedded on other branched polymers. This is a toy model which allows us to study explicitly the reaction of a statistical system on an underlying geometrical structure, a problem of interest in the study of the interaction of matter and quantized gravity. We find a phase transition at which the embedded polymers begin to cover the basis polymers. At the phase transition point the susceptibility exponent $\\gamma$ takes the value 3/4 and the ...

  19. 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.

  20. Conducting Polymers

    Indian Academy of Sciences (India)

    potential of the monomer would be less than that of the dimer, which would in turn be less than that of the polymer. Hence, the polymer generated by this oxidative .... glucose and galactose biosensors based on a silicon chip employing polypyrrole have in fact been developed by several companies. These types of sensors ...

  1. Conducting Polymers

    Indian Academy of Sciences (India)

    polymer backbone), exhibit semiconducting behavior. The discovery of dopingl led to a further dramatic increase in the conductivity of such conjugated polymers to values as ..... CERF's Comments on Modem Science. • If it's incomprehensible, it's mathematics. • If it doesn't make sense, it's either economics or psychology.

  2. Polymers & People

    Science.gov (United States)

    Lentz, Linda; Robinson, Thomas; Martin, Elizabeth; Miller, Mary; Ashburn, Norma

    2004-01-01

    Each Tuesday during the fall of 2002, teams of high school students from three South Carolina counties conducted a four-hour polymer institute for their peers. In less than two months, over 300 students visited the Charleston County Public Library in Charleston, South Carolina, to explore DNA, nylon, rubber, gluep, and other polymers. Teams of…

  3. 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.

  4. 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.

  5. Rheological behavior of a confined bead-spring cube consisting of equal Fraenkel springs

    NARCIS (Netherlands)

    Denneman, A.I.M.; Denneman, A.I.M.; Jongschaap, R.J.J.; Mellema, J.

    2000-01-01

    A general bead-spring model is used to predict linear viscoelastic properties of a non-Hookean bead-spring cube immersed in a Newtonian fluid. This K×K×K cube consist of K 3 beads with equal friction coefficients and 3K 2(K–1) equal Fraenkel springs with length q. The cube has a topology based upon

  6. 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

  7. Alginate/bacterial cellulose nanocomposite beads prepared using Gluconacetobacter xylinus and their application in lipase immobilization.

    Science.gov (United States)

    Kim, Ji Hyun; Park, Saerom; Kim, Hyungsup; Kim, Hyung Joo; Yang, Yung-Hun; Kim, Yong Hwan; Jung, Sang-Kyu; Kan, Eunsung; Lee, Sang Hyun

    2017-02-10

    Alginate/bacterial cellulose nanocomposite beads, with well-controlled size and regular spherical shapes, were prepared in a simple manner by entrapping Gluconacetobacter xylinus in barium alginate hydrogel beads, followed by cultivation of the entrapped cells in culture media with a low sodium ion concentration. The entire surface of the alginate hydrogel beads containing the cells was covered with cellulose fibers (∼30nm) after 36h of cultivation. The cellulose crystallinity index of the alginate/bacterial cellulose beads was 0.7, which was slightly lower than that of bacterial cellulose prepared by cultivating dispersed cells. The water vapor sorption capacity of the alginate/bacterial cellulose beads increased significantly from 0.07 to 38.00 (g/g dry bead) as cultivation time increased. These results clearly indicate that alginate/bacterial cellulose beads have a much higher surface area, crystallinity, and water-holding capacity than alginate beads. The immobilization of lipase on the surface of the nanocomposite beads was also investigated as a potential application of this system. The activity and specific activity of lipase immobilized on alginate/bacterial cellulose beads were 2.6- and 3.8-fold higher, respectively, than that of lipase immobilized on cellulose beads. The alginate/bacterial cellulose nanocomposite beads prepared in this study have several potential applications in the biocatalytic, biomedical, and pharmaceutical fields because of their biocompatibility, biodegradability, high crystallinity, and large surface area. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. 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.

  9. 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...... 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....

  10. 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.

  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. Monolithic silicon chip for immunofluorescence detection on single magnetic beads.

    Science.gov (United States)

    Dupont, Emile P; Labonne, Estelle; Vandevyver, Caroline; Lehmann, Ulrike; Charbon, Edoardo; Gijs, Martin A M

    2010-01-01

    While fluorescence detection is widely used for bioassays owing to its high sensitivity, a complete fluorescent microscopy setup, comprised of a light source, optical filters, a microscope body, and a camera, still is bulky equipment, compromising its use in a point-of-care environment. Here we propose an integrated monolithic silicon chip for integrated magnetic manipulation and optical detection of fluorescently labeled magnetic beads. Our approach permits microscopeless measurement of the fluorescence of a single microparticle. We demonstrate the viability of this approach by the detection of cancer biomarker 5D10 monoclonal antibodies (mAbs) in a noncompetitive sandwich immunoassay performed on the surface of magnetic beads, in a phosphate buffered saline-bovine serum albumin (PBS-BSA) solution, with a detection limit of 1 ng mL(-1).

  13. Polymer flooding

    Energy Technology Data Exchange (ETDEWEB)

    Littmann, W.

    1988-01-01

    This book covers all aspects of polymer flooding, an enhanced oil recovery method using water soluble polymers to increase the viscosity of flood water, for the displacement of crude oil from porous reservoir rocks. Although this method is becoming increasingly important, there is very little literature available for the engineer wishing to embark on such a project. In the past, polymer flooding was mainly the subject of research. The results of this research are spread over a vast number of single publications, making it difficult for someone who has not kept up-to-date with developments during the last 10-15 years to judge the suitability of polymer flooding to a particular field case. This book tries to fill that gap. An indispensable book for reservoir engineers, production engineers and lab. technicians within the petroleum industry.

  14. 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)

  15. On the occurrence of ‘bead lightning’ phenomena in long laboratory sparks

    Energy Technology Data Exchange (ETDEWEB)

    Vayanganie, S.P.A., E-mail: amilavayanganie@gmail.com [Atmospheric Physics and Lightning Research Group, University of Colombo, Colombo 03 (Sri Lanka); Cooray, V.; Rahman, Mahbubur; Hettiarachchi, Pasan; Diaz, Oscar [Lightning Research Group, The Ångström Laboratory Division of Electricity, Department of Engineering Sciences, Uppsala University, Box 534, SE-751 21 Uppsala (Sweden); Fernando, M. [Atmospheric Physics and Lightning Research Group, University of Colombo, Colombo 03 (Sri Lanka)

    2016-02-22

    The formation of bead lightning, where the lightning channel appears to break up into luminous fragments, is still an object of speculation. Here we report similar observations in laboratory discharges. Analysis of time resolved photographs shows that the discharge channel exhibits a ‘bead pattern’ in the decaying stage of the discharge and the occurrence of loops in the channel sections where the bead pattern is observed. This result presents the first evidence that the rapid cooling of non-uniform channel sections could lead to the formation of beads. It is suggested that periodically occurring non-uniform channel sections could explain the bead pattern of lightning discharges. - Highlights: • For the first time, the occurrence of bead patterns in the channel of laboratory sparks was reported. • Depending on the geometry some regions of the channel decays faster than the other sections. • A possible mechanism for the occurrence of beads in decaying states of lightning flashes is proposed.

  16. 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.

  17. 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.

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

    Science.gov (United States)

    Kotschy, Peter; Virnik, Sascha; Christ, Doris; Gaggl, Alexander

    2011-01-01

    Objective 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 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. PMID:23674909

  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. Using magnetic levitation to distinguish atomic-level differences in chemical composition of polymers, and to monitor chemical reactions on solid supports.

    Science.gov (United States)

    Mirica, Katherine A; Phillips, Scott T; Shevkoplyas, Sergey S; Whitesides, George M

    2008-12-31

    This communication describes a density-based method that uses magnetic levitation for monitoring solid-supported reactions and for distinguishing differences in chemical composition of polymers. The method is simple, rapid, and inexpensive and is similar to thin-layer chromatography (TLC; for solution-phase chemistry) in its potential for monitoring reactions in solid-phase chemistry. The technique involves levitating a sample of beads (taken from a reaction mixture) in a cuvette containing a paramagnetic solution (e.g., GdCl(3) dissolved in H(2)O) positioned between two NdFeB magnets. The vertical position at which the beads levitate corresponds to the density of the beads and correlates with the progress of a chemical reaction on a solid support. The method is particularly useful for monitoring the kinetics of reactions occurring on polymer beads.

  1. From spots to beads-PTM-peptide bead arrays for the characterization of anti-histone antibodies.

    Science.gov (United States)

    Heubach, Yvonne; Planatscher, Hannes; Sommersdorf, Cornelia; Maisch, Daniel; Maier, Julia; Joos, Thomas O; Templin, Markus F; Poetz, Oliver

    2013-03-01

    Antibodies that recognize PTMs of histones play a central role in epigenetic proteomic research. Modification-specific antibodies are employed in chromatin immunoprecipitation, for Western blotting and during the immunoprecipitation steps for MS-based global proteomic analyses. Knowledge about the antibodies' off-target binding is essential for the interpretation of experimental data. To address this challenge we developed a fast and cost efficient system for generating peptide bead arrays. We employed this method to establish a bead-based peptide array containing 384 peptides displaying phosphorylated, acetylated, methylated, and citrullinated N-terminal regions of histones H2A, H2B, H3 and H4 and controls. We profiled the binding of 40 PTM-specific antibodies important for epigenetic proteomic research. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Tailored bifunctional polymer for plutonium monitoring.

    Science.gov (United States)

    Paul, Sumana; Pandey, Ashok K; Kumar, Pranaw; Kaity, Santu; Aggarwal, Suresh K

    2014-07-01

    Monitoring of actinides with sophisticated conventional methods is affected by matrix interferences, spectral interferences, isobaric interferences, polyatomic interferences, and abundance sensitivity problems. To circumvent these limitations, a self-supported disk and membrane-supported bifunctional polymer were tailored in the present work for acidity-dependent selectivity toward Pu(IV). The bifunctional polymer was found to be better than the polymer containing either a phosphate group or a sulfonic acid group in terms of (i) higher Pu(IV) sorption efficiency at 3-4 mol L(-1) HNO3, (ii) selective preconcentration of Pu(IV) in the presence of a trivalent actinide such as Am(III), and (iii) preferential sorption of Pu(IV) in the presence of a large excess of U(VI). The bifunctional polymer was formed as a self-supported matrix by bulk polymerization and also as a 1-2 μm thin layer anchored on a microporous poly(ether sulfone) by surface grafting. The proportions of sulfonic acid and phosphate groups in both the self-supported disk and membrane-supported bifunctional polymer were found to be the same as expected from the mole proportions of monomers in polymerizing solutions used for syntheses. α radiography by a solid-state nuclear track detector indicated fairly homogeneous anchoring of the bifunctional polymer on the surface of the membrane. Pu(IV) preconcentrated on a single bifunctional bead was used for determination of the Pu isotopic composition by thermal ionization mass spectrometry. The membrane-supported bifunctional polymer was used for preconcentration and subsequent quantification of Pu(IV) by α spectrometry using the absolute efficiency at a fixed counting geometry. The analytical performance of the membrane-supported-bifunctional-polymer-based α spectrometry method was found to be highly reproducible for assay of Pu(IV) in a variety of complex samples.

  3. 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.

  4. Structure and Conductivity of Semiconducting Polymer Hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Huber, Rachel C.; Ferreira, Amy S.; Aguirre, Jordan C.; Kilbride, Daniel; Toso, Daniel B.; Mayoral, Kenny; Zhou, Z. Hong; Kopidakis, Nikos; Rubin, Yves; Schwartz, Benjamin J.; Mason, Thomas G.; Tolbert, Sarah H.

    2016-07-07

    Poly(fluorene-alt-thiophene) (PFT) is a conjugated polyelectrolyte that self-assembles into rod-like micelles in water, with the conjugated polymer backbone running along the length of the micelle. At modest concentrations (-10 mg/mL in aqueous solutions), PFT forms hydrogels, and this work focuses on understanding the structure and intermolecular interactions in those gel networks. The network structure can be directly visualized using cryo electron microscopy. Oscillatory rheology studies further tell us about connectivity within the gel network, and the data are consistent with a picture where polymer chains bridge between micelles to hold the network together. Addition of tetrahydrofuran (THF) to the gels breaks those connections, but once the THF is removed, the gel becomes stronger than it was before, presumably due to the creation of a more interconnected nanoscale architecture. Small polymer oligomers can also passivate the bridging polymer chains, breaking connections between micelles and dramatically weakening the hydrogel network. Fits to solution-phase small-angle X-ray scattering data using a Dammin bead model support the hypothesis of a bridging connection between PFT micelles, even in dilute aqueous solutions. Finally, time-resolved microwave conductivity measurements on dried samples show an increase in carrier mobility after THF annealing of the PFT gel, likely due to increased connectivity within the polymer network.

  5. 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.

  6. Detection Techniques for Biomolecules using Semi-Conductor Nanocrystals and Magnetic Beads as Labels

    Science.gov (United States)

    Chatterjee, Esha

    itself to miniaturization, is capable of mass production and is inexpensive to fabricate. The device consisted of a microwave circuit in which a slotline and a coplanar waveguide were integrated with a biochemically activated sensor area. The magnetic beads were immobilized at the sensor area by bio-specific reactions. Experiments conducted on this prototype show promising results for using ferromagnetic resonance -based detection of magnetic labels for fabrication of portable and inexpensive sensor devices. The next stage of work addresses the issue of patterning of sensing surfaces with biomolecules. The ability to selectively immobilize biomolecules on surfaces has far-reaching applications, including sensor development. A simple and widely applicable method for the photopatterning of chitosan films with biotin was presented. Chitosan is a biocompatible and biodegradable polymer. The proposed method was capable of forming spatially defined biotin features on the order of tens of microns, together with a significant reduction of non-specific protein binding and increase in hydrophilicity of the sensor surface. The entire patterning process, inclusive of the blocking step, could be completed in under an hour. This straightforward method for the selective patterning of the biocompatible polymer chitosan is expected to be widely useful in the field of bioanalysis.

  7. 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

  8. Preparation and characterization of chitosan/cashew gum beads loaded with Lippia sidoides essential oil

    Energy Technology Data Exchange (ETDEWEB)

    Paula, Haroldo C.B., E-mail: hpaula@ufc.br [Department of Analytical and Physical Chemistry, Federal University of Ceara, UFC, Fortaleza-CE (Brazil); Sombra, Fernanda Matoso; Cavalcante, Rafaela de Freitas; Abreu, Flavia O.M.S. [Department of Analytical and Physical Chemistry, Federal University of Ceara, UFC, Fortaleza-CE (Brazil); Paula, Regina C.M. de [Department of Organic and Inorganic Chemistry, Federal University of Ceara, UFC, Fortaleza-CE (Brazil)

    2011-03-12

    Beads based on chitosan (CH) and cashew gum (CG), were prepared and loaded with an essential oil with larvicide activity (Lippia sidoides - Ls). CH and CH-CG beads were characterized by scanning electron microscopy (SEM), infrared and UV-VIS spectroscopy, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), as well as, regarding their larvicide loading, swelling, in vitro and in vivo release kinetics. The oil encapsulation was evidenced by FTIR analysis and LS loading ranges from 2.4% to 4.4%. CH beads duly showed swelling degree (Q) values from 4.0 to 6.7, reaching equilibrium after 30 min, whereas crosslinked CH-CG beads showed lower swelling values, from 0.4 to 3.8, exhibiting a longer equilibrium time. Liquid transport parameters have revealed diffusion coefficient for CH-CG beads, as low as 2 x 10{sup -15} m{sup 2}/s. TGA and DSC revealed that CH:CG crosslinked beads are more thermally stable than CH beads. In vitro release follows a non-Fickian diffusion profile for both bead types, however, and a prolonged release being achieved only after beads crosslinking. In vivo release showed that both CH and CH-CG presented a prolonged larvicide effect. These aforesaid results, indicate that CH-CG beads loaded with LS are efficient for A. aegypti larval control.

  9. Fabrication of bead-size sorting chip for chemical array sensor

    Science.gov (United States)

    Park, Byung Hwa; Park, Yoon Seok; Sohn, Young-Soo; Neikirk, Dean

    2003-04-01

    Combinations of micromachined platforms and chemically sensitive micro-beads have been demonstrated for use as multi-analyte chemical and biological agent detectors. Two critical requirements for bead-based chemical detection platforms are bead retention and assembly. Separate "cover layers" have been used in the past for retention, but this constrains fluid flow through the device, and may require the use of precision spacers. In addition, since chemical sensing molecules within the beads can be quite sensitive exposure to high temperatures or harsh chemicals used in micromachining must be avoided after beads are placed in the platform. Here we present a new device whose fabrication is completed before placing the beads, and that provides both bead confinement and a means for self-assembly of arrays. Simple micromachined flexible "fingers" are used for all functions. The micromachined fingers are designed to bend out of the way as a bead is placed into a micromachined storage well, but then snap back after the bead is fully inserted into the well. We have also demonstrated that by designing different sized openings over each well it is possible to construct self-assembling bead arrays.

  10. The Sequence of Appearance of Bead Sets at the Filippovka I Burial in the Southern Urals

    Directory of Open Access Journals (Sweden)

    Anikeeva Olga Viktorovna

    2015-06-01

    Full Text Available The differences in the composition of bead sets from the Filippovka I burial were analyzed by the author in order to determine regularities in their co-occurrence. The mineralogical analysis has revealed the glass beads made of olivine and fluorite. The mineralogical and technological study allowed to classify all beads according to manufacturing techniques. On the basis of the comparison with beads of the same age from India, Persia, Middle Asia, Northern Black Sea coast, the Caucasus, and the Pamir, possible production centers have been hypothesized. The results were compared with earlier published data on bead sets from the Southern Urals burials of the late 6th - early 3rd centuries B.C. The literature data on the timing of appearance and the origin of beads analogous to those from Filippovka barrows were also analyzed. The results suggest that the observed differences in the composition of bead sets reflect the appearance or disappearance of particular bead types in the region. The analysis of mutual occurrence of certain bead types allowed to allocate two groups of the sets which are smoothly replacing each other in time. This allowed the author to reconstruct the sequence of appearance of bead sets in the Filippovka I burial.

  11. Reliability of confocal microscopy spectral imaging systems: use of multispectral beads.

    Science.gov (United States)

    Zucker, Robert M; Rigby, Paul; Clements, Ian; Salmon, Wendy; Chua, Michael

    2007-03-01

    There is a need for a standardized, impartial calibration, and validation protocol on confocal spectral imaging (CSI) microscope systems. To achieve this goal, it is necessary to have testing tools to provide a reproducible way to evaluate instrument performance. We evaluated fluorescent spectral beads (FocalCheck) from Molecular Probes/Invitrogen that consist of four pairs with emissions between 500 and 725 nm and a europium macrocycle quantum dye bead. These bead tools compliment our previously published protocol for testing spectral imaging systems that used an inexpensive multi-ion discharge lamp (MIDL) that contains Hg(+), Ar(+), and inorganic fluorophores that emits distinct, stable spectral features. We acquired the spectra of the FocalCheck beads on a Zeiss 510 Meta, a Leica TCS-SP1, a Leica SP2 AOBS, an Olympus FV 1000, and a Nikon C1Si confocal systems and a PARISS microscopic spectral system and of the europium beads on the Leica TCS-SP1 and PARISS spectral imaging systems. A lack of performance with some equipment between 650 and 750 nm was identified using the far red pair of the FocalCheck beads. The position of the slider in front of PMT 2 that reflects light into PMT 1 and PMT 3 affected the measurement of all bead intensities. Unmixing algorithms were used to separate beads with different fluorochromes and separate two fluorochromes on the same bead. The FocalCheck multi-spectral beads yielded similar profiles on four CSI systems and a PARISS spectral system. The utilization of the spectral FocalCheck beads is helpful to evaluate proper spectral performance, especially in the far red region. Europium beads provide a very narrow spectrum that can help to identify machines that have spectral problems. The dyes located on individual beads or mixed together in ring-core configuration can be used as test particles to demonstrate spectral unmixing with various algorithms.

  12. 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.

  13. 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

  14. 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.

  15. 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

  16. Bioactive bead-mediated transformation of plants with large DNA fragments.

    Science.gov (United States)

    Wada, Naoki; Cartagena, Joyce A; Khemkladngoen, Naruemon; Fukui, Kiichi

    2012-01-01

    The efficient transformation of plants with large DNA molecules containing a set of useful genes would provide vast possibilities for the genetic improvement of agricultural as well as nonagricultural plants. The development of the bioactive beads (BABs) transformation method has proven useful for introduction of large DNA molecules into plant cells. In this chapter, the BABs transformation method used for the transformation of a 100-kb BAC DNA construct containing wheat genes into rice will be presented. Furthermore, the improved production method for BABs will be described. With the conventional method for producing BABs, the bead size varies, and the larger beads tend to carry fewer DNA molecules than the smaller beads. Thus, in order to facilitate the preparation of BABs with more uniform sizes, a simple set-up -composed of a sine wave sound generator and microsyringe pump was fabricated. Using this bead-maker set-up, uniform and smaller beads could be produced which enhance the transformation efficiency.

  17. [Magnetic beads adsorption-PCR detection method of four common foodborne pathogens in food].

    Science.gov (United States)

    Wang, Ping; Hu, Yue; Tian, Xue; Yang, Hairong; Zhao, Yongsheng; Chen, Ying

    2014-07-01

    To evaluate the adsorption capacity of magnetic beads for common foodborne pathogens. Escherichia coli, Staphylococcus aureus, Listeria monocytogenes and Cronobacter sakazakii were used as targets, the suitable conditions were obtained by optimization the incubation time, bead size, reaction temperature and so on. The adsorption efficiency of the magnetic beads in analog samples was also tested. The optimum conditions were as follows: 2.0 - 3.0 microm diameter magnetic beads 50 microl, incubation for 60 min under 37 degrees C. In analog samples, the adsorption efficiency of the magnetic beads for Escherichia coli, Staphylococcus aureus, Listeria monocytogenes and Cronobacter sakazakii in juice, milk, duck meat were 50% - 84%, 46% - 66%, 54% - 74%, respectively. Magnetic beads enrichment technique has high adsorption efficiency, simple to operate, which is meet the requirement for PCR detection.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Elution of platinum from carboplatin-impregnated calcium sulfate hemihydrate beads in vitro.

    Science.gov (United States)

    Tulipan, Rachel J; Phillips, Heidi; Garrett, Laura D; Dirikolu, Levent; Mitchell, Mark A

    2016-11-01

    OBJECTIVE To characterize the elution of platinum from carboplatin-impregnated calcium sulfate hemihydrate (CSH) beads in vitro. SAMPLE 60 carboplatin-impregnated CSH beads and 9 CSH beads without added carboplatin (controls). PROCEDURES Carboplatin-impregnated CSH beads (each containing 4.6 mg of carboplatin [2.4 mg of platinum]) were placed into separate 10-mL plastic tubes containing 5 mL of PBSS in groups of 1, 3, 6, or 10; 3 control beads were placed into a single tube of PBSS at the same volume. Experiments were conducted in triplicate at 37°C and a pH of 7.4 with constant agitation. Eluent samples were collected at 1, 2, 3, 6, 12, 24, and 72 hours. Samples were analyzed for platinum content by inductively coupled plasma-mass spectrometry. RESULTS The mean concentration of platinum released per carboplatin-impregnated bead over 72 hours was 445.3 mg/L. Cumulative concentrations of platinum eluted increased as the number of beads per tube increased. There was a significant difference in platinum concentrations over time, with values increasing over the first 12 hours and then declining for all tubes. There was also a significant difference in percentage of total incorporated platinum released into tubes with different numbers of beads: the percentage of eluted platinum was higher in tubes containing 1 or 3 beads than in those containing 6 or 10 beads. CONCLUSIONS AND CLINICAL RELEVANCE Carboplatin-impregnated CSH beads eluted platinum over 72 hours. Further studies are needed to determine whether implantation of carboplatin-impregnated CSH beads results in detectable levels of platinum systemically and whether the platinum concentrations eluted locally are toxic to tumor cells.

  3. Fabrication of micromagnetic beads with molecular recognition/electron-transfer peptides for the sensing of ovalbumin

    Energy Technology Data Exchange (ETDEWEB)

    Sugawara, Kazuharu, E-mail: kzsuga@maebashi-it.ac.jp [Maebashi Institute of Technology, Gunma, 371-0816 (Japan); Kuramitz, Hideki [Department of Environmental Biology and Chemistry, Graduate School of Science and Engineering for Research, University of Toyama, Toyama, 930-8555 (Japan); Shinohara, Hiroki [Maebashi Institute of Technology, Gunma, 371-0816 (Japan)

    2017-03-15

    Electrochemical sensing of ovalbumin (OVA) was performed using magnetic beads with OVA recognition (RNRCKGTDVQAW)/electron-transfer (YYYYC) peptides. The focus of this study was to construct a highly sensitive and regenerative tool for OVA detection based on the interaction between a protein and peptide-1(RNRCKGTDVQAWYYYYC). The peptide-1 was introduced to the bead through four types of cross-linking reagents. Magnetic beads of different sizes with N-(6-maleimidocaproyloxy)sulfosuccinimide (Sulfo-EMCS) were also prepared. An oxidation peak due to tyrosine residues at 0.65 V depended on the distance of the electron-transfer peptide from the bead surface and on the surface area of the magnetic beads that contacted the electrode surface. The response of the electro-transfer peptide moiety was decreased because the protein was accumulated via the recognition peptide on the beads. When using Sulfo-EMCS and beads that were 6.0–6.9 μm in diameter, the calibration curve of OVA was linear and ranged from 8.0 × 10{sup −13} to 2.0 × 10{sup −11} M. To regenerate the magnetic beads, the measurements were achieved after removal of the OVA using a denaturing reagent. When OVA was added to fetal bovine serum containing a complex matrix, OVA was recovered at a rate of 98–100%. Consequently, these magnetic beads could be a powerful tool for the sensing of OVA in real samples. - Highlights: • Ovalbumin recognition/electron-transfer peptides were immobilized on magnetic beads. • The accumulation of the protein through the peptides on the beads caused the change of electrode response. • The magnetic beads could be reused for sensing of ovalbumin.

  4. AMS Radiocarbon Dating of Shell Beads and Ornaments from CA-ORA-378

    OpenAIRE

    Gibson, Robert O; Koerper, Henry C.

    2000-01-01

    Accelerator mass spectrometry (AMS) dates for nine shell beads and two shell ornaments are used to test the application to Orange County of a temporal sequence developed for the Santa Barbara Channel region. Olivella cupped, Olivella oblique spire-removed, Olivella end-removed, Mytilus disc, and Megathura small square ring and Megathura oval ring beads/ornaments fell within time ranges predicted by the bead/ornament chronology developed by Chester King (1981, 1990) for the Chumash area. Olive...

  5. 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...

  6. 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:

  7. Polymer Microneedles

    NARCIS (Netherlands)

    Yeshurun, Yehoshua; Hefetz, Meir; Berenschot, Johan W.; de Boer, Meint J.; Altpeter, Dominique; Boom, Garrit; Boom, G.

    2003-01-01

    A method for producing microneedles. The method including disposing a first layer of a radiation sensitive polymer on to a working surface and selectively irradiating the first layer such that the first layer has at least one irradiated region and at least one non-irradiated region. The method also

  8. P(HPMA/EGDMA) beads grafted with fibrous chains by SI-ATRP method: agmatine functionalized affinity beads for selective separation of serum albumin.

    Science.gov (United States)

    Bayramoglu, Gulay; Yakup Arica, M

    2014-02-01

    In this paper, novel core-shell polymeric affinity beads based on fibrous grafting and functionalization with a salt resistance affinity ligand were developed to separate and deplete serum albumin (SA) from human serum. Poly(hydroxypropyl methacrylate/ethyleneglycole dimethacrylate), p(HPMA/EGDMA), beads were prepared via suspension polymerization, and were grafted with poly(glycidyl methacrylate) (p(GMA)) via surface-initiated atom transfer radical polymerization (SI-ATRP) method. The grafted p(GMA) fibrous chains on the beads were modified with an affinity ligand (i.e., agmatine). The binding capacity of the affinity beads to SA was determined using aqueous solution of SA in a batch system. Batch adsorption studies showed that the amount of adsorbed SA was found to be 156.7 mg/g at 25 °C. The maximum adsorption capacity for affinity beads was observed at around pH 5.5. Adsorption of SA onto affinity beads significantly increased with increasing temperature, and reached a value 177.8 mg/g beads at 35 °C. The equilibrium data were found to be well described by Langmuir model, while the kinetic data were well fitted to the pseudo-second-order kinetic. The degree of the purity of SA was determined by using HPLC. Before and after adsorption, the peak areas of SA were used in the calculation of separated SA.

  9. Post-denitrification using alginate beads containing organic carbon and activated sludge microorganisms.

    Science.gov (United States)

    Shams, Dilawar Farhan; Rubio, Alexandre; Elefsiniotis, Panagiotis; Singhal, Naresh

    2016-10-01

    Nitrate concentration in the final effluent is a key issue in pre-denitrification biological treatment systems. This study investigated post-denitrification with alginate beads containing immobilized activated sludge microorganisms and organic carbon source. A batch study was first performed to identify suitable carbon sources among acetate, glucose, calcium tartrate, starch and canola oil on the basis of nitrate removal and bead stability. Canola oil and starch beads exhibited significantly higher denitrification rates, greater bead stability and lower nitrite accumulation (6 mg/L and 10 mg/L, respectively). Glucose and acetate beads showed longer acclimation phases and degraded faster whereas tartrate beads had higher nitrite build-up (39 mg/L) and degraded due to brittleness. Post-denitrification with canola oil and starch beads was investigated in the final clarifier of a coupled upflow bioreactor and aerobic system treating synthetic dairy farm wastewater, and showed a denitrification efficiency of >90%. Beads faded in 12 days due to alginate degradation. Therefore, enhancement in bead strength or use of more stable nontoxic gel would be required to further prolong the treatment. Moreover, this study was conducted at laboratory scale and further research is needed for application in real systems.

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

    Energy Technology Data Exchange (ETDEWEB)

    Metzner, C; Raupach, C; Mierke, C T; Fabry, B, E-mail: bfabry@biomed.uni-erlangen.d [Center for Medical Physics and Technology, University of Erlangen-Nuremberg, Erlangen (Germany)

    2010-05-19

    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 {beta}: MSD {approx} D (t/t{sub 0}){sup {beta}}. Here we studied whether D and {beta} 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 {mu}m). 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

  11. Artifactual dendritic beading in rat spinal cord induced by perfusion with cold saline and paraformaldehyde.

    Science.gov (United States)

    Zhang, Shu-Xin; Holmberg, Eric G; Geddes, James W

    2007-06-15

    Extensive dendritic beading of MAP2 (microtubule-associated protein 2) immunoreactivity has previously been observed in the contused rat spinal cord. However, we have also observed dendritic beading in occasional uninjured animals. The purpose of this study was to examine the possibility that perfusion conditions contributed to the dendritic beading. Under deep anesthesia, uninjured rats (adult female Long-Evans, 200-225 g) were transcardially perfused with 0.9% saline solution followed by 4% paraformaldehyde at cold (4 degrees C) or warm (20 degrees C) temperature, and at a low (20 ml/min) or high (50 ml/min) flow rate. Dendrites were visualized by MAP2 immunoreactivity. The results demonstrate that perfusion with cold solutions at a high flow rate induces pronounced dendritic beading, and when perfused at a low flow rate, results in moderate dendritic beading. Warm perfusates did not induce dendritic beading when administered at a low flow rate, but occasional beading was observed with a high flow rate. Western blots revealed spectrin breakdown, but not MAP2 loss, in rats perfused with cold saline solution at a high flow rate, conditions that also resulted in dendritic beading. These findings demonstrate that dendritic morphology is sensitive to both temperature and flow rate of the perfusate. Warm fixative and a low perfusion flow rate minimized the perfusion-induced dendritic beading.

  12. Synthesis of beaded and entwined carbon nanofibers in Ni:Al alloy catalyst.

    Science.gov (United States)

    Pradhan, Debabrata; Sharon, Maheshwar; Kumar, Mukul; Ando, Yoshinori

    2007-03-01

    This paper reports two new types of carbon nanofibers synthesis by thermal decomposition of n-hexane in presence of Ni-Al alloy in hydrogen atmosphere at 1100 degrees C. One type is "beaded fibers" in which spherical carbon beads (approximately 1 microm) are regularly grown from outer surface of fibers (approximately 0.3 microm). The other new microstructure is "entwined fibers" in which multiple nanofibers of diameter approximately 100 nm grow self-entwined like a braid of hair. Both bead-fiber bonding (in beaded fibers) and fiber-fiber interaction (in entwined fibers) are strong to be detached/unfolded by 30-min ultrasonication.

  13. Robust Optimization of Alginate-Carbopol 940 Bead Formulations

    Science.gov (United States)

    López-Cacho, J. M.; González-R, Pedro L.; Talero, B.; Rabasco, A. M.; González-Rodríguez, M. L.

    2012-01-01

    Formulation process is a very complex activity which sometimes implicates taking decisions about parameters or variables to obtain the best results in a high variability or uncertainty context. Therefore, robust optimization tools can be very useful for obtaining high quality formulations. This paper proposes the optimization of different responses through the robust Taguchi method. Each response was evaluated like a noise variable, allowing the application of Taguchi techniques to obtain a response under the point of view of the signal to noise ratio. A L 18 Taguchi orthogonal array design was employed to investigate the effect of eight independent variables involved in the formulation of alginate-Carbopol beads. Responses evaluated were related to drug release profile from beads (t 50% and AUC), swelling performance, encapsulation efficiency, shape and size parameters. Confirmation tests to verify the prediction model were carried out and the obtained results were very similar to those predicted in every profile. Results reveal that the robust optimization is a very useful approach that allows greater precision and accuracy to the desired value. PMID:22645438

  14. 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.

  15. 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.

  16. 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.

  17. Robust Optimization of Alginate-Carbopol 940 Bead Formulations

    Directory of Open Access Journals (Sweden)

    J. M. López-Cacho

    2012-01-01

    Full Text Available Formulation process is a very complex activity which sometimes implicates taking decisions about parameters or variables to obtain the best results in a high variability or uncertainty context. Therefore, robust optimization tools can be very useful for obtaining high quality formulations. This paper proposes the optimization of different responses through the robust Taguchi method. Each response was evaluated like a noise variable, allowing the application of Taguchi techniques to obtain a response under the point of view of the signal to noise ratio. A L18 Taguchi orthogonal array design was employed to investigate the effect of eight independent variables involved in the formulation of alginate-Carbopol beads. Responses evaluated were related to drug release profile from beads (t50% and AUC, swelling performance, encapsulation efficiency, shape and size parameters. Confirmation tests to verify the prediction model were carried out and the obtained results were very similar to those predicted in every profile. Results reveal that the robust optimization is a very useful approach that allows greater precision and accuracy to the desired value.

  18. 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.

  19. Triboelectric generator based on a moving charged bead

    Science.gov (United States)

    Kim, Jihoon; Chae, Soo Sang; Han, Sun Woong; Lee, Keun Ho; Ki, Tae Hoon; Oh, Jin Young; Lee, Ji Hoon; Kim, Won Shik; Jang, Woo Soon; Baik, Hong Koo

    2016-11-01

    An energy harvesting system using a triboelectric generator (TEG), which converts a small amount of mechanical energy to available electrical energy, has recently been developed by combining a simple one-directional mechanical force (contact and separation or sliding back and forth) with a 2D device materials. However, with regard to using the TEG in real world applications, there is no TEG design suitable for utilizing a variety of mechanical forces and for generating triboelectric charge in various environmental conditions, especially under high relative humidity. In this work, we introduce a design for a humidity-independent triboelectric generator (HITEG) that can generate triboelectric charges with a granular system by simple rotating or shaking under high relative humidity conditions. The HITEG can generate an open-circuit voltage of 81.63 V and a short-circuit current of 213.9 nA using 80 polytetrafluoroethylene beads. Electronic supplementary information (ESI) available: More detailed information for analytic calculation via COMSOL about available charge distance between the PTFE bead and Cu electrode, illustration of the speed-dependence contact area, and time dependent long-term stability.

  20. Magnetic bead based assays for complement component C5.

    Science.gov (United States)

    DiScipio, Richard G; Schraufstatter, Ingrid U

    2017-11-01

    Two novel magnetic agarose bead based assays have been developed to measure complement component C5 interaction with C3b and the Factor I Modules (FIMs) of C7. One innovation was to couple C3b onto the magnetic agarose bead using the alternative pathway C3 convertase, which resulted in a linkage of the ligand by a covalent ester bond. A second innovation was to employ nickel ion charged N,N,N'-tris(carboxymethyl)ethylene-diamine-magnetic agarose to capture recombinantly prepared C7 FIMs that were expressed with an oligo-histidine linker followed by an acidic domain that provided a spacer enabling the C7 modules exposure to C5. Detection was brought about by peroxidase coupled to C5. Both assays exhibited adequate statistics suitable for screening. As examples of the utility of these new methods, we chose to examine influence of natural products on C5 interaction. Fucoidan and β-glucans were observed to inhibit C3b-C5 interaction, and dextran sulfate was similarly active; however, rosmarinic acid had no measurable effect. In contrast only β-glucans from two species of macrofungi were able to interfere with interaction of C5 with the FIMs of C7. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Synthesis and characterization of polymer-based hybrid materials via oxidation of Mn(II) using N-chlorosulphonamide polymers

    Energy Technology Data Exchange (ETDEWEB)

    Ciechanowska, Agnieszka [Department of Industrial Chemistry, Wroclaw University of Economics, ul. Komandorska 118/120, 53-345 Wroclaw (Poland); Hanuza, Jerzy [Department of Bioorganic Chemistry, Wroclaw University of Economics, ul. Komandorska 118/120, 53-345 Wroclaw (Poland); Institute of Low Temperature and Structure Research, Polish Academy of Sciences, PO Box 1410, 50-950 Wroclaw (Poland); Kociolek-Balawejder, Elzbieta, E-mail: elzbieta.kociolek-balawejder@ue.wroc.pl [Department of Industrial Chemistry, Wroclaw University of Economics, ul. Komandorska 118/120, 53-345 Wroclaw (Poland); Stanislawska, Ewa [Department of Industrial Chemistry, Wroclaw University of Economics, ul. Komandorska 118/120, 53-345 Wroclaw (Poland)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer Copolymer containing -SO{sub 2}NClNa functional groups is effective oxidant of Mn{sup 2+} ions. Black-Right-Pointing-Pointer Product of the oxidation reaction - hydrous manganese oxide was precipitated within the polymer matrix. Black-Right-Pointing-Pointer Oxidation of Mn(II) by N-chlorosulphonamide polymers leads to polymer-based hybrid materials. - Abstract: Polymer/metal oxide hybrids represent an perspective class of materials with specific properties. Polymer-based hybrid materials containing manganese oxide/hydroxide due to their catalytic, adsorptive and oxidizing properties are the group of materials with large potential applications. Beads of three macroporous and macromolecular oxidants, polystyrene crosslinked by divinylbenzene containing pendant groups: N-chlorosulphonamide in Na{sup +} form, N-chlorosulphonamide in H{sup +} form and N,N-dichlorosulphonamide were used to oxidize Mn(II) to Mn(IV). The investigation were carried out using both the batchwise and column methods, and 0.01 M MnSO{sub 4} as well as 0.0025 M MnSO{sub 4} solutions were used. We found that the investigated oxidation reaction is favoured by the alkaline medium. The best product in the form of black brilliant beads containing 75 mg Mn g{sup -1} was obtained using polymer supported -SO{sub 2}NClNa groups. The prepared material was characterized by: FT-IR, EPR and reflectance UV-vis spectra, SEM, X-ray diffraction, porous characteristics, magnetic measurements and thermal analysis. It has been found that hydrous manganese oxide(IV) was well dispersed within the polymer matrix. Amorphous and paramagnetic properties make this new product potentially useful in adsorptive and catalytic processes particularly in oxidative sorption processes.

  2. Tailoring Wettability Through the Surface Modification of Electro-spun Polymers by Plasma and Sol-gel Treatments

    Science.gov (United States)

    2014-11-01

    nanoparticles , sol-gel reactions and by producing beads-on-a-string morphologies. Low surface energy was added by using fluorinated polymers, or through... nanoparticles ................................................................... 13 3.2.3 Effect of TEOS addition to electrospinning solutions...could benefit a number of applications: anti-biofouling; corrosion resistant paints for hulls; coatings that prevent ice buildup; water, stain and

  3. Density-tunable lightweight polymer composites with dual-functional ability of efficient EMI shielding and heat dissipation.

    Science.gov (United States)

    Lee, Seung Hwan; Yu, Seunggun; Shahzad, Faisal; Kim, Woo Nyon; Park, Cheolmin; Hong, Soon Man; Koo, Chong Min

    2017-09-21

    Lightweight dual-functional materials with high EMI shielding performance and thermal conductivity are of great importance in modern cutting-edge applications, such as mobile electronics, automotive, aerospace, and military. Unfortunately, a clear material solution has not emerged yet. Herein, we demonstrate a simple and effective way to fabricate lightweight metal-based polymer composites with dual-functional ability of excellent EMI shielding effectiveness and thermal conductivity using expandable polymer bead-templated Cu hollow beads. The low-density Cu hollow beads (ρ ∼ 0.44 g cm-3) were fabricated through electroless plating of Cu on the expanded polymer beads with ultralow density (ρ ∼ 0.02 g cm-3). The resulting composites that formed a continuous 3D Cu network with a very small Cu content (∼9.8 vol%) exhibited excellent EMI shielding (110.7 dB at 7 GHz) and thermal conductivity (7.0 W m-1 K-1) with isotropic features. Moreover, the densities of the composites are tunable from 1.28 to 0.59 g cm-3 in accordance with the purpose of their applications. To the best of our knowledge, the resulting composites are the best lightweight dual-functional materials with exceptionally high EMI SE and thermal conductivity performance among synthetic polymer composites.

  4. 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

  5. A Novel Inherently Radiopaque Bead for Transarterial Embolization to Treat Liver Cancer - A Pre-clinical Study.

    Science.gov (United States)

    Duran, Rafael; Sharma, Karun; Dreher, Matthew R; Ashrafi, Koorosh; Mirpour, Sahar; Lin, MingDe; Schernthaner, Ruediger E; Schlachter, Todd R; Tacher, Vania; Lewis, Andrew L; Willis, Sean; den Hartog, Mark; Radaelli, Alessandro; Negussie, Ayele H; Wood, Bradford J; Geschwind, Jean-François H

    2016-01-01

    Embolotherapy using microshperes is currently performed with soluble contrast to aid in visualization. However, administered payload visibility dimishes soon after delivery due to soluble contrast washout, leaving the radiolucent bead's location unknown. The objective of our study was to characterize inherently radiopaque beads (RO Beads) in terms of physicomechanical properties, deliverability and imaging visibility in a rabbit VX2 liver tumor model. RO Beads, which are based on LC Bead® platform, were compared to LC Bead. Bead size (light microscopy), equilibrium water content (EWC), density, X-ray attenuation and iodine distribution (micro-CT), suspension (settling times), deliverability and in vitro penetration were investigated. Fifteen rabbits were embolized with either LC Bead or RO Beads + soluble contrast (iodixanol-320), or RO Beads+dextrose. Appearance was evaluated with fluoroscopy, X-ray single shot, cone-beam CT (CBCT). Both bead types had a similar size distribution. RO Beads had lower EWC (60-72%) and higher density (1.21-1.36 g/cc) with a homogeneous iodine distribution within the bead's interior. RO Beads suspension time was shorter than LC Bead, with durable suspension (>5 min) in 100% iodixanol. RO Beads ≤300 µm were deliverable through a 2.3-Fr microcatheter. Both bead types showed similar penetration. Soluble contrast could identify target and non-target embolization on fluoroscopy during administration. However, the imaging appearance vanished quickly for LC Bead as contrast washed-out. RO Beads+contrast significantly increased visibility on X-ray single shot compared to LC Bead+contrast in target and non-target arteries (P=0.0043). Similarly, RO beads demonstrated better visibility on CBCT in target arteries (P=0.0238) with a trend in non-target arteries (P=0.0519). RO Beads+dextrose were not sufficiently visible to monitor embolization using fluoroscopy. RO Beads provide better conspicuity to determine target and non-target embolization

  6. Influence of Polymer Relaxation Time on the Electrospinning Process: Numerical Investigation

    Directory of Open Access Journals (Sweden)

    Siddharth Gadkari

    2017-10-01

    Full Text Available “Electrospinnability”, or the ease with which a solution can be used to obtain bead-free uniform fibers, depends on a large number of parameters, including solution properties, process parameters and ambient conditions. In this study, the effect of the polymer relaxation time on electrospinning of dilute polymer solutions is investigated numerically. It is shown that elastic stresses (ES increase exponentially with the Deborah number ( D e . For each polymer concentration there exists a critical D e below which the ES are insufficient to overcome capillary stresses (CS and lead to the formation of beaded fibers. However, above the critical D e , there is a higher probability of the ES overcoming the CS and leading to the formation of uniform fibers. This analysis suggests the possibility of improved electrospinnability even with dilute polymer solutions, provided the relaxation time is sufficiently large. It is also found that changes in the drag coefficient due to change in the polymer conformation and self-concentration of polymer molecules would become significant for the electrospinning of polymer solutions with a longer relaxation time and high conductivity.

  7. Phthalocyanine polymers

    Science.gov (United States)

    Achar, B. N.; Fohlen, G. M.; Parker, J. A. (Inventor)

    1985-01-01

    A method of forming 4,4',4'',4''' -tetraamino phthalocyanines involves reducing 4,4',4'',4''' -tetranitro phthalocyanines, polymerizing the metal tetraamino phthalocyanines with a tetracarboxylic dianhydride (preferably aromatic) or copolymerizing with a tetracarboxylic dianhydride and a diamine (preferably also aromatic) to produce amic acids which are then dehydrocyclized to imides. Thermally and oxidatively stable polymers result which form tough, flexible films, varnishes, adhesives, and fibers.

  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. Biomaterial-associated infection of gentamicin-loaded PMMA beads in orthopaedic revision surgery

    NARCIS (Netherlands)

    Neut, D; van de Belt, H; Stokroos, [No Value; van Horn, [No Value; van der Mei, HC; Busscher, HJ

    In two-stage orthopaedic revision surgery, high local levels of antibiotics are achieved after removal of an infected prosthesis through temporary implantation of gentamicin-loaded beads. However, despite their antibiotic release, these beads act as a biomaterial surface to which bacteria

  10. Fluidized-bed and packed-bed characteristics of gel beads

    NARCIS (Netherlands)

    Zessen, van E.; Tramper, J.; Rinzema, A.; Beeftink, H.H.

    2005-01-01

    A liquid-fluidized bed or packed bed with gel beads is attractive as an immobilized-cell bioreactor. The performance of such bioreactors is influenced by the physical behavior of these beads. Three different but related aspects involving the drag force between particles and liquid were studied for

  11. A bead-based suspension array for the serological detection of Trichinella in pigs

    NARCIS (Netherlands)

    Wal, van der F.J.; Achterberg, R.P.; Kant, A.; Maassen, C.B.M.

    2013-01-01

    The feasibility of using bead-based suspension arrays to detect serological evidence of Trichinella in pigs was assessed. Trichinella spiralis excretory–secretory antigen was covalently coupled to paramagnetic beads and used to bind serum antibodies, which were subsequently detected using anti-swine

  12. 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)

  13. 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 fiel...

  14. Rifabutin-loaded Floating Gellan Gum Beads: Effect of Calcium and ...

    African Journals Online (AJOL)

    Purpose: To formulate rifabutin-loaded floating gel beads for stomach-specific release. Methods: Rifabutin-loaded floating gellan gum beads were prepared by ionotropic calcium-induced gelation in acidic medium. In-vitro buoyancy and drug release studies were performed using a USP dissolution apparatus type II in ...

  15. 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...

  16. The preconcentration of mercury and methylmercury on dithizone-coated polystyrene beads.

    Science.gov (United States)

    Howard, A G; Arbab-Zavar, M H

    1979-09-01

    The preconcentration of "inorganic" and methyl mercury cations from aqueous solution is described. The procedure involves collection of mercury on dithizone-coated macroreticular resin beads prior to analysis by cold-vapour atomic absorption spectroscopy. The beads are readily prepared before use and give rise to quantitative selective recovery of "inorganic" and methyl mercury from fresh and saline water samples.

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

    Science.gov (United States)

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

    2012-12-01

    We developed Fe3+-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 Fe3+ 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 Fe3+-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 Fe3+-crosslinked AC beads protected and controlled the release of protein, demonstrating that such beads present a promising protein therapeutic carrier for the oral delivery.

  18. 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.

  19. 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...

  20. In vivo cleansing efficacy of biodegradable exfoliating beads assessed by skin bioengineering techniques.

    Science.gov (United States)

    Kitsongsermthon, J; Duangweang, K; Kreepoke, J; Tansirikongkol, A

    2017-11-01

    The plastic microbeads, used in many cleansers, will be banned in cosmetic and personal care products within 2017 since they are non-degradable and can disturb the living organisms in water reservoirs. Various choices of biodegradable beads are commercially available, but their efficacy has not been proven yet. This study aimed to compare the cleansing efficacy in dirt and sebum removal aspects of three types of exfoliating beads. The gel scrubs with polyethylene (PE) beads, mannan beads or wax beads, were formulated and evaluated for their stability. The in vivo evaluation was done in 38 healthy volunteers and the skin irritation, efficacy for dirt and sebum removal were measured by Mexameter® , Colorimeter® , and Sebumeter® , respectively. The selected gel scrubs did not cause an irritation in any volunteers. The differences in dirt residues between before and after scrubbing were not statistically significant among three gel scrubs and the similar result was also reported in the sebum removal study. All gel scrubs demonstrated the comparable cleansing efficacy in term of dirt and sebum removal. Thus, mannan beads and wax beads may be replaced non-biodegradable PE beads to achieve the similar cleansing effect. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  1. Preparation and in vitro characterization of gentamycin-impregnated biodegradable beads suitable for treatment of osteomyelitis.

    Science.gov (United States)

    Meyer, J D; Falk, R F; Kelly, R M; Shively, J E; Withrow, S J; Dernell, W S; Kroll, D J; Randolph, T W; Manning, M C

    1998-09-01

    A new method for preparing poly(L-lactide) (PLA) biodegradable beads impregnated with an ionic aminoglycoside, gentamycin, is described. The process employs hydrophobic ion pairing to solubilize gentamycin in a solvent compatible with PLA, followed by precipitation with a compressed antisolvent (supercritical carbon dioxide). The resulting precipitate is a homogeneous dispersion of the ion-paired drug in PLA microspheres. The microspheres are approximately 1 microm in diameter and can be compressed into beads (3-6 mm in diameter) strung on surgical sutures for implantation. The bead strings exhibit no significant change in release kinetics upon sterilization with a hydrogen peroxide plasma (Ster-Rad). The kinetics of gentamycin release from the PLA beads are consistent with a matrix-controlled diffusion mechanism. While nonbiodegradable poly(methyl methacrylate) (PMMA) beads initially release gentamycin in a similar manner, the drug release from PMMA ceases after 8 or 9 weeks, while the PLA beads continue to release drug for over 4 months. Moreover, only 10% of the gentamycin is released from the PMMA beads, while PLA beads release more than 60% of their load, if serum is present in the release medium. The PLA system displays improved release kinetics relative to PMMA, is biodegradable, is unaltered by gas sterilization, can be used for a range of antibiotics, and can be manipulated without disintegration. These are all desirable properties for an implantable drug delivery system for the prevention or treatment of osteomyelitis.

  2. Effectiveness of beads for tracking small-scale molecular motor dynamics

    Science.gov (United States)

    Lade, Steven J.; Craig, Erin M.; Linke, Heiner

    2011-08-01

    Investigations into molecular motor dynamics are increasingly focused on small-scale features of the motor’s motion. We define performance measures of a common type of single-molecule motility assay, the bead assay, for its ability to detect such features. Using numerical models, we explore the dependence of assay performance on a number of experimentally controllable parameters, including bead size, optical force, and the method of attaching the bead to the motor. We find that the best parameter choice depends on the objective of the experiments, and give a guide to parameter selection. Comparison of the models against experimental data from a recent bead assay of myosin V exemplifies how our methods can also be used to extract additional information from bead assays, particularly that related to small-scale features. By analyzing the experimental data we find evidence for previously undetected multiple waiting states of the bead-motor complex. Furthermore, from numerical simulations we find that equilibrium bead dynamics display features previously attributed to aborted motor steps, and that bead dynamics alone can produce multiple subphases during a step.

  3. Translational diffusion of chain polymers. I. Improved variational bounds

    Science.gov (United States)

    Fixman, Marshall

    1986-04-01

    Variational estimates of an upper bound to the diffusion constant have been obtained from equilibrium simulations of Gaussian and cubic lattice chains. The trial functions that represent the deformation of the chain due to the external force have been inferred from the previous dynamical simulations of short Gaussian chains, which implied that local rather than large scale deformations were important. The variational results are in excellent agreement with the dynamical results for short Gaussian chains, and with exact results for rigid, planar, polygonal polymers. The variational results for long Gaussian chains (up to 896 beads) and cubic lattice chains (up to 448 beads), give an extrapolated reduction of the diffusion constant due to fluctuating hydrodynamic interaction of about 8% below the Kirkwood formula. The exact amount of the decrease may depend on friction constants and local chain structure.

  4. Bead-based microfluidic immunoassay for diagnosis of Johne's disease

    Energy Technology Data Exchange (ETDEWEB)

    Wadhwa, Ashutosh [University of Tennessee, Center for Wildlife Health, Department of Forestry; Foote, Robert [ORNL; Shaw, Robert W [ORNL; Eda, Shigetoshi [ORNL

    2012-01-01

    Microfluidics technology offers a platform for development of point-of-care diagnostic devices for various infectious diseases. In this study, we examined whether serodiagnosis of Johne s disease (JD) can be conducted in a bead-based microfluidic assay system. Magnetic micro-beads were coated with antigens of the causative agent of JD, Mycobacterium avium subsp. paratuberculosis. The antigen-coated beads were incubated with serum samples of JD-positive or negative serum samples and then with a fluorescently-labeled secondary antibody (SAB). To confirm binding of serum antibodies to the antigen, the beads were subjected to flow cytometric analysis. Different conditions (dilutions of serum and SAB, types of SAB, and types of magnetic beads) were optimized for a great degree of differentiation between the JD-negative and JD-positive samples. Using the optimized conditions, we tested a well-classified set of 155 serum samples from JD negative and JD-positive cattle by using the bead-based flow cytometric assay. Of 105 JD-positive samples, 63 samples (60%) showed higher antibody binding levels than a cut-off value determined by using antibody binding levels of JD-negative samples. In contrast, only 43-49 JD-positive samples showed higher antibody binding levels than the cut-off value when the samples were tested by commercially-available immunoassays. Microfluidic assays were performed by magnetically immobilizing a number of beads within a microchannel of a glass microchip and detecting antibody on the collected beads by laser-induced fluorescence. Antigen-coated magnetic beads treated with bovine serum sample and fluorescently-labeled SAB were loaded into a microchannel to measure the fluorescence (reflecting level of antibody binding) on the beads in the microfluidic system. When the results of five bovine serum samples obtained with the system were compared to those obtained with the flow cytometer, a high level of correlation (linear regression, r2 = 0.994) was

  5. 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......, 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....... 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...

  6. Biosorption of uranium (VI) by immobilized Aspergillus fumigatus beads

    Energy Technology Data Exchange (ETDEWEB)

    Wang Jingsong, E-mail: xhwjs@163.co [School of Urban Construction, University of South China, 28 West Changsheng Road, Hengyang, Hunan 421001 (China) and Hunan Key Laboratory of Pollution Control and Resource Reuse, University of South China, Henyang, Hunan 421001 (China); Hu Xinjiang [School of Urban Construction, University of South China, 28 West Changsheng Road, Hengyang, Hunan 421001 (China); College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Liu Yunguo [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Xie Shuibo [School of Urban Construction, University of South China, 28 West Changsheng Road, Hengyang, Hunan 421001 (China); Hunan Key Laboratory of Pollution Control and Resource Reuse, University of South China, Henyang, Hunan 421001 (China); Bao Zhenglei [School of Urban Construction, University of South China, 28 West Changsheng Road, Hengyang, Hunan 421001 (China)

    2010-06-15

    Biosorption of uranium (VI) ions by immobilized Aspergillus fumigatus beads was investigated in a batch system. The influences of solution pH, biosorbent dose, U (VI) concentration, and contact time on U (VI) biosorption were studied. The results indicated that the adsorption capacity was strongly affected by the solution pH, the biosorbent dose and initial U (VI) concentration. Optimum biosorption was observed at pH 5.0, biosrobent dose (w/v) 2.5%, initial U (VI) concentration 60 mg L{sup -1}. Biosorption equilibrium was established in 120 min. The adsorption process conformed to the Freunlich and Temkin isothermal adsorption models. The dynamic adsorption model conformed to pseudo-second order model.

  7. Parallel RNA extraction using magnetic beads and a droplet array

    Science.gov (United States)

    Shi, Xu; Chen, Chun-Hong; Gao, Weimin; Meldrum, Deirdre R.

    2015-01-01

    Nucleic acid extraction is a necessary step for most genomic/transcriptomic analyses, but it often requires complicated mechanisms to be integrated into a lab-on-a-chip device. Here, we present a simple, effective configuration for rapidly obtaining purified RNA from low concentration cell medium. This Total RNA Extraction Droplet Array (TREDA) utilizes an array of surface-adhering droplets to facilitate the transportation of magnetic purification beads seamlessly through individual buffer solutions without solid structures. The fabrication of TREDA chips is rapid and does not require a microfabrication facility or expertise. The process takes less than 5 minutes. When purifying mRNA from bulk marine diatom samples, its repeatability and extraction efficiency are comparable to conventional tube-based operations. We demonstrate that TREDA can extract the total mRNA of about 10 marine diatom cells, indicating that the sensitivity of TREDA approaches single-digit cell numbers. PMID:25519439

  8. Numerical Modelling of Insulin and Amyloglucosidase Release from Swelling Ca-Alginate Beads

    DEFF Research Database (Denmark)

    Rasmussen, Michael R.; Snabe, T.; Pedersen, Lars Haastrup

    2003-01-01

    The release of insulin hexamer (39 kD) and amyloglucosidase (AMG, 97 kD), entrapped in spherical Ca–alginate beads, was investigated. While the release of insulin could be described solely by diffusion this was not the case for the 1.6 (r m /r m) larger AMG protein, where rm is the Stokes......–Einstein effective molecular radius. Because the alginate bead size was not constant during the release experiments, it was hypothesised that in addition to the diffusional mass transfer, a non-negligible convective flow of liquid in or out of the beads was present due to swelling or shrinkage, respectively...... convective flow in the numerical model, release could be described more accurately. The numerical model was able to describe the release  characteristics from both shrinking, swelling, and non-swelling alginate beads. To evaluate the effect of bead swelling on the protein release rate, a swelling modulus...

  9. Ripple structure-generated hybrid electrokinetics for on-chip mixing and separating of functionalized beads.

    Science.gov (United States)

    Cheng, I-Fang; Chiang, Sheng-Chuan; Chung, Cheng-Che; Yeh, Trai-Ming; Chang, Hsien-Chang

    2014-11-01

    We present an electrokinetics-based microfluidic platform that is capable of on-chip manipulating, mixing, and separating microparticles through adjusting the interrelated magnitudes of dielectrophoresis and AC electroosmosis. Hybrid electrokinetic phenomenon is generated from an electric field-induced micro-ripple structure made of ultraviolet-curable glue. Size-dependent particle separation and selective removal over the ripple structure is demonstrated successfully. Varying the waveform from sine-wave to square-wave allows generating a fluid convection at specific positions to mix the antibody-functionalized beads and antigen. Potential application in the bead-based immunoassay was also demonstrated for immuno-reaction and subsequently separating the bead-bead aggregate and non-binding beads on-chip.

  10. 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.

  11. Effect of Polymer Concentration, Rotational Speed, and Solvent Mixture on Fiber Formation Using Forcespinning®

    Directory of Open Access Journals (Sweden)

    Nancy Obregon

    2016-06-01

    Full Text Available Polycaprolactone (PCL fibers were produced using Forcespinning® (FS. The effects of PCL concentration, solvent mixture, and the spinneret rotational speed on fiber formation were evaluated. The concentration of the polymer in the solvents was a critical determinant of the solution viscosity. Lower PCL concentrations resulted in low solution viscosities with a correspondingly low fiber production rate with many beads. Bead-free fibers with high production rate and uniform fiber diameter distribution were obtained from the optimum PCL concentration (i.e., 12.5 wt% with tetrahydrofuran (THF as the solvent. The addition of N, N-dimethylformamide (DMF to the THF solvent promoted the gradual formation of beads, split fibers, and generally affected the distribution of fiber diameters. The crystallinity of PCL fibers was also affected by the processing conditions, spinning speed, and solvent mixture.

  12. A versatile size-coded flow cytometric bead assay for simultaneous detection of multiple microRNAs coupled with a two-step cascading signal amplification.

    Science.gov (United States)

    Qiu, Liying; Zhang, Yuecheng; Liu, Chenghui; Li, Zhengping

    2017-03-07

    A versatile flow cytometric bead assay is developed for the sensitive and simultaneous detection of multiple microRNAs that combines an elegant enzyme-mediated cascading signal amplification on magnetic beads with a novel bead size-encoding mechanism.

  13. Porous polymer monoliths: morphology, porous properties, polymer nanoscale gel structure and their impact on chromatographic performance.

    Science.gov (United States)

    Nischang, Ivo

    2013-04-26

    Porous monoliths based on organic precursors undergoing free-radical cross-linking polymerization in porogenic solvents emerged approximately two decades ago as an alternative stationary phase material for diverse applications including liquid chromatography. Though having a profound difference in morphology to their earlier generation polymer bead-based counterparts, they are often based on similar chemistries and as such show certain peculiarities with respect to transport and performance in liquid chromatography applications. Polymer monoliths typically consist of a globule-like, three-dimensionally adhered backbone, which is in a contrast to the silica monoliths having a bi-continuous mesoporous skeleton. Both material types possess large flow-through pores making them desirable for high performance liquid chromatography and other flow-through applications. The current review is devoted to a critical appraisal of the major challenges that researchers face in the retrieval of the never-ending demand of efficiency at often forgotten and desired selectivity and retention in separations using porous polymer monoliths. Therefore, an attempt is made to establish profound links of polymer monoliths to their earlier generation polymer-based particulate beds and differences to silica-based materials. These links are associated with an emerging morphological understanding of the polymer monoliths porous flow-through pore structure, the nanoscale backbone chemistry, and related chromatographic performances in both theoretical and experimental studies. Associated with this understanding, existing attempts in improving flow and transport performance of polymer monoliths are described and discussed. Such developments are addressing morphological concerns with respect to homogeneity and detailed design of pore space, but also tailoring backbone nanostructural chemistry to modulate mass transfer. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Evaluation of polyacrylonitrile (PAN) as a binding polymer for absorbers used to treat liquid radioactive wastes

    Energy Technology Data Exchange (ETDEWEB)

    Sebesta, F.; John, J.; Motl, A.; Stamberg, K. [Czech Technical University in Prague (Czech Republic). Dept. of Nuclear Chemistry

    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{sub 3} + 1M NaNO{sub 3}, 1M NaOH + 1M NaNO{sub 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{sup 3}--10{sup 6} Gy (10{sup 5}--10{sup 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{sub 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. 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.

  16. A Novel Inherently Radiopaque Bead for Transarterial Embolization to Treat Liver Cancer - A Pre-clinical Study

    National Research Council Canada - National Science Library

    Duran, Rafael; Sharma, Karun; Dreher, Matthew R; Ashrafi, Koorosh; Mirpour, Sahar; Lin, MingDe; Schernthaner, Ruediger E; Schlachter, Todd R; Tacher, Vania; Lewis, Andrew L; Willis, Sean; den Hartog, Mark; Radaelli, Alessandro; Negussie, Ayele H; Wood, Bradford J; Geschwind, Jean-François H

    2016-01-01

    .... The objective of our study was to characterize inherently radiopaque beads (RO Beads) in terms of physicomechanical properties, deliverability and imaging visibility in a rabbit VX2 liver tumor model...

  17. Taste masking of azithromycin by resin complex and sustained release through interpenetrating polymer network with functionalized biopolymers.

    Science.gov (United States)

    Rajesh, A Michael; Popat, Kiritkumar Mangaldas

    2017-05-01

    The objective was to evaluate taste masking of azithromycin (AZI) by ion exchange resins (IERs) and the formation of covalent semi interpenetrating polymer network (IPN) beads using chitosan (CS) and sodium carboxylated agarose (SCAG) for sustained release of drug. Methacrylic acid (MAA)-based IERs were prepared by suspension polymerization method. Drug release complexes (DRCs) were prepared by different drug:resin ratios i.e. 1:1, 1:2 and 1:4. The resultant DRCs were characterized using DSC, FTIR, PXRD, in vivo and in vitro taste masking, and in vitro drug release at gastric pH. IPN beads were prepared by entrapping DRCs with bio polymers and cross linked with trisodium citrate (NaCIT), and further cross-linked with glutaraldehyde (GA) for sustained release of AZI. In vitro and in vivo taste masking studies showed that MD1:4 DRC formulation was optimal. The release of AZI from DRC was found to be very fast at gastric pH i.e. 97.37 ± 1.02% within 45 min. The formation of IPN beads was confirmed by FTIR. The release of drug from IPN beads at gastric and intestinal pH was found to be "taste masking and newly formulated IPN beads demonstrated sustained release of AZI.

  18. Tunable Optical Polymer Systems

    National Research Council Canada - National Science Library

    Jenekhe, S. A; Bard, Allen J; Chen, S. H; Hammond, P. T; Rothberg, L. J

    2004-01-01

    .... The synthesis and properties of new electrochromic polymers are described. Electrochromic devices incorporating conjugated polymers have been fabricated and found to be durable past 100,000 cycles...

  19. Evaluation of the Effect of Psyllium on the Viability of Lactobacillus Acidophilus in Alginate-Polyl Lysine Beads

    Directory of Open Access Journals (Sweden)

    Jaleh Esmaeilzadeh

    2016-09-01

    Methods:Beads were prepared using extrusion technique. Poly-l-lysine as second coat was incorporated on optimum alginate/psyllium beads using immersion technique. Beads were characterized in terms of size, encapsulation efficiency, integrity and bacterial survival in harsh conditions. Results:Beads with narrow size distribution ranging from 1.85 ± 0.05 to 2.40 ± 0.18 mm with encapsulation efficiency higher than 96% were achieved. Psyllium concentrations in beads did not produce constant trend in bead sizes. Surface topography by SEM showed that substitution of psyllium enhanced integrity of obtained beads. Psyllium successfully protected the bacteria against acidic condition and lyophilization equal to alginate in the beads. Better survivability with beads of alginate/psyllium-poly-l-lysine was achieved with around 2 log rise in bacterial count in acid condition compared to the corresponding single coat beads. Conclusion:Alginate/psyllium (1:2 beads with narrow size distribution and high encapsulation efficiency of the bacteria have been achieved. Presence of psyllium produced a much smoother and integrated surface texture for the beads with sufficient protection of the bacteria against acidic condition as much as alginate. Considering the health benefits of psyllium and its prebiotic activity, psyllium can be beneficially replaced in part for alginate in probiotic coating.

  20. 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.

  1. From Commodity Polymers to Functional Polymers

    OpenAIRE

    Tao Xiang,; Ling-Ren Wang; Lang Ma; Zhi-Yuan Han; Rui Wang; Chong Cheng; Yi Xia; Hui Qin; Chang-Sheng Zhao

    2014-01-01

    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 outs...

  2. 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.

  3. Enrichment of cancer stem cell-like cells by culture in alginate gel beads.

    Science.gov (United States)

    Xu, Xiao-xi; Liu, Chang; Liu, Yang; Yang, Li; Li, Nan; Guo, Xin; Sun, Guang-wei; Ma, Xiao-jun

    2014-05-10

    Cancer stem cells (CSCs) are most likely the reason of cancer reoccurrence and metastasis. For further elucidation of the mechanism underlying the characteristics of CSCs, it is necessary to develop efficient culture systems to culture and expand CSCs. In this study, a three-dimensional (3D) culture system based on alginate gel (ALG) beads was reported to enrich CSCs. Two cell lines derived from different histologic origins were encapsulated in ALG beads respectively and the expansion of CSCs was investigated. Compared with two-dimensional (2D) culture, the proportion of cells with CSC-like phenotypes was significantly increased in ALG beads. Expression levels of CSC-related genes were greater in ALG beads than in 2D culture. The increase of CSC proportion after being cultured within ALG beads was further confirmed by enhanced tumorigenicity in vivo. Moreover, increased metastasis ability and higher anti-cancer drug resistance were also observed in 3D-cultured cells. Furthermore, we found that it was hypoxia, through the upregulation of hypoxia-inducible factors (HIFs) that occurred in ALG beads to induce the increasing of CSC proportion. Therefore, ALG bead was an efficient culture system for CSC enrichment, which might provide a useful platform for CSC research and promote the development of new anti-cancer therapies targeting CSCs. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. A bacteria-based bead for possible self-healing marine concrete applications

    Science.gov (United States)

    Palin, D.; Wiktor, V.; Jonkers, H. M.

    2016-08-01

    This work presents a bacteria-based bead for potential self-healing concrete applications in low-temperature marine environments. The bead consisting of calcium alginate encapsulated bacterial spores and mineral precursor compounds was assessed for: oxygen consumption, swelling, and its ability to form a biocomposite in a simulative marine concrete crack solution (SMCCS) at 8 °C. After six days immersion in the SMCCS the bacteria-based beads formed a calcite crust on their surface and calcite inclusions in their network, resulting in a calcite-alginate biocomposite. Beads swelled by 300% to a maximum diameter of 3 mm, while theoretical calculations estimate that 0.112 g of the beads were able to produce ˜1 mm3 of calcite after 14 days immersion; providing the bead with considerable crack healing potential. The bacteria-based bead shows great potential for the development of self-healing concrete in low-temperature marine environments, while the formation of a biocomposite healing material represents an exciting avenue for self-healing concrete research.

  5. Aluminium and radiation cross-linked carboxymethyl sago pulp beads for colon targeted delivery.

    Science.gov (United States)

    Thenapakiam, Sathasivam; Kumar, Devakumar Ganesh; Pushpamalar, Janarthanan; Saravanan, Muniyandy

    2013-04-15

    The carboxymethyl sago pulp (CMSP) with a degree of substitution of 0.4% was synthesized from sago waste. The CMSP beads with an average diameter of 3.1-4.8 mm were formed by aluminium chloride gelation as well as further cross-linked by irradiation. To evaluate colon targeted release, a model drug, 5-aminosalicylic acid (5-ASA) was encapsulated in CMSP beads. Fourier-transform infrared spectroscopy and X-ray diffraction studies indicated intact and amorphous nature of entrapped drug. A pH dependent drug release was observed, and about 90% of the drug was released only at pH 7.4 over 9 h. Irradiated beads were resisted the drug release in an acidic environment at a higher extent than non-irradiated beads. The drug release from 6% (w/w) of 5-ASA loaded bead followed zero order, whereas, 15 and 22% loaded beads followed first order. The release exponent n value suggests non-fickian transport of 5-ASA from the beads. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Superparamagnetic poly(methyl methacrylate) beads for nattokinase purification from fermentation broth.

    Science.gov (United States)

    Yang, Chengli; Xing, Jianmin; Guan, Yueping; Liu, Huizhou

    2006-09-01

    An effective method for purification of nattokinase from fermentation broth using magnetic poly(methyl methacrylate) (PMMA) beads immobilized with p-aminobenzamidine was proposed in this study. Firstly, magnetic PMMA beads with a narrow size distribution were prepared by spraying suspension polymerization. Then, they were highly functionalized via transesterification reaction with polyethylene glycol. The surface hydroxyl-modified magnetic beads obtained were further modified with chloroethylamine to transfer the surface amino-modified magnetic functional beads. The morphology and surface functionality of the magnetic beads were examined by scanning electron microscopy and Fourier transform infrared. An affinity ligand, p-aminobenzamidine was covalently immobilized to the amino-modified magnetic beads by the glutaraldehyde method for nattokinase purification directly from the fermentation broth. The purification factor and the recovery of the enzyme activity were found to be 8.7 and 85%, respectively. The purification of nattokinase from fermentation broth by magnetic beads only took 40 min, which shows a very fast purification of nattokinase compared to traditional purification methods.

  7. 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.

  8. Management of chronic osteomyelitis in a developing country using ceftriaxone-PMMA beads: an initial study.

    Science.gov (United States)

    Alonge, T O; Ogunlade, S O; Omololu, A B; Fashina, A N; Oluwatosin, A

    2002-04-01

    Chronic osteomyelitis is a debilitating disease that is fairly common in developing countries. Various operative techniques have been adopted in the management of this disease but there have been few reports of their use in Africa. In this report, we present our experience of the use of a modified two-staged Belfast operation in patients with chronic osteomyelitis in Ibadan, Nigeria. An important modification of the procedure was the substitution of gentamicin beads (Septopal) with ceftriaxone-polymethylmethacrylate (PMMA) beads at the saucerised segment of bone at the first stage. Thirty-four patients with chronic osteomyelitis had the two-stage Belfast operation in 35 long bones; of these, 32 patients had ceftriaxone-PMMA antibiotic beads inserted at the saucerised segment of bone at the first stage, while the other two patients had gentamicin beads inserted. One of the two patients who had gentamicin beads had a residual collection of pus at second stage surgery but, following a repeat debridement, the cavity was rid of infection. There was recurrence of infection in three patients (8.6%) who had a suction drain inserted at the first stage and in six patients (17.1%) who had no suction drain at the first stage. The locally produced ceftriaxone-PMMA beads were found to be as efficient as the commercially available gentamicin beads in eluting antibiotics locally, thereby eliminating the residual infection in the bone cavities after the first stage. Another important outcome was a fourfold saving in cost in choosing to use ceftriaxone-PMMA beads rather than gentamicin beads.

  9. Digital microfluidics-enabled single-molecule detection by printing and sealing single magnetic beads in femtoliter droplets.

    Science.gov (United States)

    Witters, Daan; Knez, Karel; Ceyssens, Frederik; Puers, Robert; Lammertyn, Jeroen

    2013-06-07

    Digital microfluidics is introduced as a novel platform with unique advantages for performing single-molecule detection. We demonstrate how superparamagnetic beads, used for capturing single protein molecules, can be printed with unprecedentedly high loading efficiency and single bead resolution on an electrowetting-on-dielectric-based digital microfluidic chip by micropatterning the Teflon-AF surface of the device. By transporting droplets containing suspended superparamagnetic beads over a hydrophilic-in-hydrophobic micropatterned Teflon-AF surface, single beads are trapped inside the hydrophilic microwells due to their selective wettability and tailored dimensions. Digital microfluidics presents the following advantages for printing and sealing magnetic beads for single-molecule detection: (i) droplets containing suspended beads can be transported back and forth over the array of hydrophilic microwells to obtain high loading efficiencies of microwells with single beads, (ii) the use of hydrophilic-in-hydrophobic patterns permits the use of a magnet to speed up the bead transfer process to the wells, while the receding droplet meniscus removes excess beads off the chip surface and thereby shortens the bead patterning time, and (iii) reagents can be transported over the printed beads multiple times, while capillary forces and a magnet hold the printed beads in place. High loading efficiencies (98% with a CV of 0.9%) of single beads in microwells were obtained by transporting droplets of suspended beads over the array 10 times in less than 1 min, which is much higher than previously reported methods (40-60%), while the total surface area needed for performing single-molecule detection can be decreased. The performance of the device was demonstrated by fluorescent detection of the presence of the biotinylated enzyme β-galactosidase on streptavidin-coated beads with a linear dynamic range of 4 orders of magnitude ranging from 10 aM to 90 fM.

  10. Lipase immobilization into porous chitoxan beads: activities in aqueous and organic media and lipase localization.

    Science.gov (United States)

    Magnin, D; Dumitriu, S; Magny, P; Chornet, E

    2001-01-01

    Lipases were noncovalently immobilized in Chitoxan, a polyionic hydrogel obtained by complexation between chitosan and xanthan. The properties of free and immobilized lipases have been compared. In the aqueous medium, the activity was twice as high for immobilized lipases as for free lipases. Immobilized lipases in chitoxan were able to hydrolyze triacylglycerols in three distinct organic solvent media. At the microstructural level, lipases were not distributed uniformly in the chitoxan beads. Higher concentrations of lipase were found in the outer membrane-like layer of the beads, as compared with lower concentrations in the inner part of the beads.

  11. 5,000 years old Egyptian iron beads made from hammered meteoritic iron

    OpenAIRE

    Rehren, T.; Belgya, T.; Jambon, A.; Kali, G.; Kasztovszky, Z.; Kis, Z.; Kovacs, I.; Maroti, B.; Martinon-Torres, M.; Miniaci, G.; Pigott, V. C.; Radivojevic, M.; Rosta, L.; Szentmiklosi, L.; Szokefalvi-Nagy, Z.

    2013-01-01

    The earliest known iron artefacts are nine small beads securely dated to circa 3200 BC, from two burials in Gerzeh, northern Egypt. We show that these beads were made from meteoritic iron, and shaped by careful hammering the metal into thin sheets before rolling them into tubes. The study demonstrates the ability of neutron and X-ray methods to determine the nature of the material even after complete corrosion of the iron metal. The iron beads were strung into a necklace together with other e...

  12. CHITOSAN BEADS WITH MAGNETICS PARTICLES AND THEIR APPLICATION IN THE ADSORPTION OF IONS Cu (II)

    OpenAIRE

    Tapia H., N.; Dpto. de Fisicoquímica, Universidad Nacional Mayor de San Marcos Lima, Perú; Cabrejos G., J.; Dpto. Fisicoquímica, FQIQ Universidad Nacional Mayor de San Marcos Lima, Perú; Rojas P., N.; Dpto. Fisicoquímica, FQIQ Universidad Nacional Mayor de San Marcos Lima, Perú; Chasquibol S., N.; Dpto. Química Analítica, FQIQ Universidad Nacional Mayor de San Marcos Lima, Perú; Yarango R., A.; Dpto. Fisicoquímica, FQIQ Universidad Nacional Mayor de San Marcos Lima, Perú; Torres D., F.; Dpto. Fisicoquímica, FQIQ Universidad Nacional Mayor de San Marcos Lima, Perú; Becerra V., E.; Dpto. Química Analítica, FQIQ Universidad Nacional Mayor de San Marcos Lima, Perú

    2014-01-01

    The objective of this work is to prepare chitosan beads with magnetic properties for use in the adsorption of Cu (II). Through a process reported in the literature have been obtained with micro chitosan beads magnetite particles of2,5 mm diameter in the wet state and diameter of 0,8 mm when dry. Subsequently chitosan beads adsorption used for Cu (II), in a batch system, determining which optimum pH is in the range of 4.7 to 5.2. The study of the kinetics of the adsorption process showed that ...

  13. 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

    2014-01-01

    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. PMID:24710333

  14. Bacillus thuringiensis HCB6 Amylase Immobilization by Chitosan Beads

    Science.gov (United States)

    Zusfahair; Ningsih, D. R.; Kartika, D.; Fatoni, A.; Zuliana, A. L.

    2017-02-01

    The purpose of this study was to optimize the amylase immobilization using a chitosan bead and to characterize immobilized amylase of Bacillus thuringiensis Bacteria HCB6. This study was started of amylase production, continued by immobilization optimization including ratio of chitosan:enzymes, enzyme-matrix contact time, substrate concentration, pH effect, incubation temperature effect, reaction time, and stability of immobilized enzyme. Amylase activity assay was dinitro salicylic (DNS) method. The results showed the optimum chitosan:enzyme ratio was 2.5: 1 (v/v), immobilization contact time of 18 hours and immobilization efficiency of 87.93%. Furthermore, immobilized amylase of B. thuringiensis HCB6 showed optimum substrate concentration of 1.5%, optimum pH of 6, optimum incubation temperature of 37 ° C, and the reaction time of 30 minutes. The Michaelis-Menten constant KM value for free and immobilized amylase were 5.30% and 1.33% respectively. Immobilized amylase can be used up to five times with the remaining activity of 43.3%.

  15. Universal approach for selective trace metal determinations via sequential injection-bead injection-lab-on-valve using renewable hydrophobic bead surfaces as reagent carriers

    DEFF Research Database (Denmark)

    Long, Xiangbao; Miró, Manuel; Hansen, Elo Harald

    2005-01-01

    involves the use of poly(styrene-divinylbenzene) beads containing pendant octadecyl moieties (C18-PS/DVB), which are preimpregnated with a selective organic metal chelating agent prior to the automatic manipulation of the beads in the microbore conduits of the LOV unit. By adapting this approach......A new concept is presented for selective and sensitive determination of trace metals via electrothermal atomic absorption spectrometry (ETAAS) based on the principle of bead injection (BI) with renewable reversed-phase surfaces in a sequential injection-lab-on-valve (SI-LOV) mode. The methodology......, the immobilization of the most suitable chelating agent can be effected irrespective of the kinetics involved, optimal reaction conditions can be used for implementing the chelating reaction of the target metal analyte with the immobilized reagent, and an added degree of freedom is offered in selecting the most...

  16. 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.

  17. Shape memory polymers

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Thomas S.; Bearinger, Jane P.

    2017-08-29

    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 hydroxl 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.

  18. One-step isolation of plasma membrane proteins using magnetic beads with immobilized concanavalin A

    DEFF Research Database (Denmark)

    Lee, Yu-Chen; Block, Gregory; Chen, Huiwen

    2008-01-01

    We have developed a simple method for isolating and purifying plasma membrane proteins from various cell types. This one-step affinity-chromatography method uses the property of the lectin concanavalin A (ConA) and the technique of magnetic bead separation to obtain highly purified plasma membrane...... proteins from crude membrane preparations or cell lines. ConA is immobilized onto magnetic beads by binding biotinylated ConA to streptavidin magnetic beads. When these ConA magnetic beads were used to enrich plasma membranes from a crude membrane preparation, this procedure resulted in 3.7-fold enrichment...... of plasma membrane marker 5'-nucleotidase activity with 70% recovery of the activity in the crude membrane fraction of rat liver. In agreement with the results of 5'-nucleotidase activity, immunoblotting with antibodies specific for a rat liver plasma membrane protein, CEACAM1, indicated that CEACAM1...

  19. 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 differential sensor geometry. The sensor surfaces are functionalized with wild type (WT) and mutant type (MT) capture probes, differing by a single base insertion (a single nucleotide polymorphism, SNP). Complementary biotinylated targets in suspension couple streptavidin magnetic beads to the sensor surface....... The beads are magnetized by the field arising from the bias current passed through the sensors. We demonstrate the first on-chip measurements of the melting of DNA hybrids upon a ramping of the temperature. This overcomes the limitation of using a single washing condition at constant temperature. Moreover...

  20. The Ten Beads Method: A Novel Way to Collect Quantitative Data in Rural Uganda

    OpenAIRE

    Francis Mulekya Bwambale; Moyer, Cheryl A.; Innocent Komakech; Fred Wabwire-Mangen; Lori, Jody R

    2013-01-01

    This paper illustrates how locally appropriate methods can be used to collect quantitative data from illiterate respondents. This method uses local beads to represent quantities, which is a novel yet potentially valuable methodological improvement over standard Western survey methods.

  1. A tunable cancer cell filter using magnetic beads: cellular and fluid dynamic simulations

    CERN Document Server

    Gusenbauer, Markus; Bance, Simon; Exl, Lukas; Reichel, Franz; Oezelt, Harald; Schrefl, Thomas

    2011-01-01

    In the field of biomedicine magnetic beads are used for drug delivery and to treat hyperthermia. Here we propose to use self-organized bead structures to isolate circulating tumor cells using lab-on-chip technologies. Typically blood flows past microposts functionalized with antibodies for circulating tumor cells. Creating these microposts with interacting magnetic beads makes it possible to tune the geometry in size, position and shape. We develop a simulation tool that combines micromagnetics, discrete particle dynamics and fluid dynamics, in order to design micropost arrays made of interacting beads. For the simulation of blood flow we use the Lattice-Boltzmann method with immersed elastic blood cell models. Parallelization distributes large fluid and particle dynamic simulations over available resources to reduce overall calculation time.

  2. 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.

  3. Two-phase mixed media dielectric with macro dielectric beads for enhancing resistivity and breakdown strength

    Science.gov (United States)

    Falabella, Steven; Meyer, Glenn A; Tang, Vincent; Guethlein, Gary

    2014-06-10

    A two-phase mixed media insulator having a dielectric fluid filling the interstices between macro-sized dielectric beads packed into a confined volume, so that the packed dielectric beads inhibit electro-hydrodynamically driven current flows of the dielectric liquid and thereby increase the resistivity and breakdown strength of the two-phase insulator over the dielectric liquid alone. In addition, an electrical apparatus incorporates the two-phase mixed media insulator to insulate between electrical components of different electrical potentials. And a method of electrically insulating between electrical components of different electrical potentials fills a confined volume between the electrical components with the two-phase dielectric composite, so that the macro dielectric beads are packed in the confined volume and interstices formed between the macro dielectric beads are filled with the dielectric liquid.

  4. 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.

  5. 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.

  6. 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.

  7. A bead-assisted flow cytometry method for the semi-quantitative analysis of Extracellular Vesicles

    National Research Council Canada - National Science Library

    Henar Suárez; Ana Gámez-Valero; Raquel Reyes; Soraya López-Martín; María Josefa Rodríguez; José L Carrascosa; Carlos Cabañas; Francesc E Borràs; María Yáñez-Mó

    2017-01-01

    .... EVs were isolated from in vitro cultured cells-conditioned medium and biological fluids by size exclusion chromatography and coupled to latex beads to allow their detection by standard flow cytometers...

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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...

  13. Feasibility of using glass-bead thermoluminescent dosimeters for radiotherapy treatment plan verification

    Science.gov (United States)

    Jordan, Tom J; Distefano, Gail; Bradley, David A; Spyrou, Nicholas M; Nisbet, Andrew; Clark, Catharine H

    2015-01-01

    Objective: To investigate the feasibility of using glass beads as novel thermoluminescent dosemeters (TLDs) for radiotherapy treatment plan verification. Methods: Commercially available glass beads with a size of 1-mm thickness and 2-mm diameter were characterized as TLDs. Five clinical treatment plans including a conventional larynx, a conformal prostate, an intensity-modulated radiotherapy (IMRT) prostate and two stereotactic body radiation therapy (SBRT) lung plans were transferred onto a CT scan of a water-equivalent phantom (Solid Water®, Gammex, Middleton, WI) and the dose distribution recalculated. The number of monitor units was maintained from the clinical plan and delivered accordingly. The doses determined by the glass beads were compared with those measured by a graphite-walled ionization chamber, and the respective expected doses were determined by the treatment-planning system (TPS) calculation. Results: The mean percentage difference between measured dose with the glass beads and TPS was found to be 0.3%, −0.1%, 0.4%, 1.8% and 1.7% for the conventional larynx, conformal prostate, IMRT prostate and each of the SBRT delivery techniques, respectively. The percentage difference between measured dose with the ionization chamber and glass bead was found to be −1.2%, −1.4%, −0.1%, −0.9% and 2.4% for the above-mentioned plans, respectively. The results of measured doses with the glass beads and ionization chamber in comparison with expected doses from the TPS were analysed using a two-sided paired t-test, and there was no significant difference at p glass-bead TLDs as dosemeters in a range of clinical plan verifications. Advances in knowledge: Commercial glass beads are utilized as low-cost novel TLDs for treatment-plan verification. PMID:26258442

  14. A novel multiplex bead-based platform highlights the diversity of extracellular vesicles

    OpenAIRE

    Wild, Stefan; Koliha, Nina; Wiencek, Yvonne; Heider, Ute; Jüngst, Christian; Kladt, Nikolay; Krauthäuser, Susanne; Ian C. D. Johnston; Bosio, Andreas; Schauss, Astrid

    2016-01-01

    The surface protein composition of extracellular vesicles (EVs) is related to the originating cell and may play a role in vesicle function. Knowledge of the protein content of individual EVs is still limited because of the technical challenges to analyse small vesicles. Here, we introduce a novel multiplex bead-based platform to investigate up to 39 different surface markers in one sample. The combination of capture antibody beads with fluorescently labelled detection antibodies allows the an...

  15. 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...

  16. Feasibility of magnetic bead technology for concentration of mycobacteria in sputum prior to fluorescence microscopy

    Directory of Open Access Journals (Sweden)

    Manabe Yukari

    2011-05-01

    Full Text Available Abstract Background Direct sputum smear microscopy is the mainstay of TB diagnosis in most low and middle income countries, and is highly specific for Mycobacterium tuberculosis in such settings. However it is limited by low sensitivity, particularly in HIV co-infected patients. Concentration by centrifugation has been reported to be more sensitive than direct smear preparation, but is only suitable for referral laboratories. Simpler concentration methods that could be applied in peripheral laboratories are urgently needed. Methods We evaluated the feasibility of an early prototype ligand-coated magnetic bead technology to concentrate M. tuberculosis prior to detection by LED-based fluorescence microscopy compared with direct Ziehl-Neelsen microscopy and direct and concentrated fluorescence microscopy in a reference laboratory in Kampala, Uganda. Results were compared with MGIT 960 liquid culture and Lowenstein-Jensen culture. Results Compared to culture, concentrated FM had significantly higher sensitivity than direct ZN (74.8% and 51.4%, magnetic bead-FM (65.4% and direct FM (58.9%. The sensitivity of magnetic bead FM was significantly higher than direct ZN (p Conclusion The sensitivity of the early prototype magnetic bead FM was lower than concentrated FM, similar to direct FM, and significantly higher than direct ZN. Both magnetic bead and concentration by centrifugation led to reduced specificity compared with the direct smear methods. Some magnetic bead FM false positive results were not easily explained and should be further investigated. The prototype version of the magnetic bead procedure tested here was of similar complexity to concentration by centrifugation. As such, if the sensitivity of the magnetic bead FM could be improved in future versions of the technology, this may offer a viable alternative to centrifugation.

  17. Feasibility of using glass-bead thermoluminescent dosimeters for radiotherapy treatment plan verification.

    Science.gov (United States)

    Jafari, Shakardokht M; Jordan, Tom J; Distefano, Gail; Bradley, David A; Spyrou, Nicholas M; Nisbet, Andrew; Clark, Catharine H

    2015-01-01

    To investigate the feasibility of using glass beads as novel thermoluminescent dosemeters (TLDs) for radiotherapy treatment plan verification. Commercially available glass beads with a size of 1-mm thickness and 2-mm diameter were characterized as TLDs. Five clinical treatment plans including a conventional larynx, a conformal prostate, an intensity-modulated radiotherapy (IMRT) prostate and two stereotactic body radiation therapy (SBRT) lung plans were transferred onto a CT scan of a water-equivalent phantom (Solid Water(®), Gammex, Middleton, WI) and the dose distribution recalculated. The number of monitor units was maintained from the clinical plan and delivered accordingly. The doses determined by the glass beads were compared with those measured by a graphite-walled ionization chamber, and the respective expected doses were determined by the treatment-planning system (TPS) calculation. The mean percentage difference between measured dose with the glass beads and TPS was found to be 0.3%, -0.1%, 0.4%, 1.8% and 1.7% for the conventional larynx, conformal prostate, IMRT prostate and each of the SBRT delivery techniques, respectively. The percentage difference between measured dose with the ionization chamber and glass bead was found to be -1.2%, -1.4%, -0.1%, -0.9% and 2.4% for the above-mentioned plans, respectively. The results of measured doses with the glass beads and ionization chamber in comparison with expected doses from the TPS were analysed using a two-sided paired t-test, and there was no significant difference at p glass-bead TLDs as dosemeters in a range of clinical plan verifications. Commercial glass beads are utilized as low-cost novel TLDs for treatment-plan verification.

  18. Preparation of spherical activated phenol-formaldehyde beads from bamboo tar for adsorption of toluene.

    Science.gov (United States)

    Huang, Ying-Pin; Hsi, Hsing-Cheng; Liu, Szu-Chen

    2013-08-01

    Bamboo tar is a waste by-product from the process of bamboo charcoal production. After distillation under reduced pressure, bamboo tar becomes a highly viscous liquid containing phenolic compounds at more than 70 wt%. Therefore, bamboo tar could be an excellent replacement for the phenolic compounds produced by the decomposition of petroleum. In this study, bamboo tar was mixed with formalin under a weak alkaline condition to form cured phenol-formaldehyde (PF) beads through suspension polymerization. In total, 35% of the obtained PF resin produced spherical beads with a particle size ranging from 9 to 16 mesh. The char yield after 500 degrees C carbonization was 60.4 wt%, according to thermogravimetric analysis. This high char yield is advantageous for the subsequent activation process. After physical activation using CO2 at 900 degrees C for 2 hr the carbide yield was up to 73.0 wt%. The specific surface area of activated PF beads was dependent on the activation time and temperature. Toluene adsorption results suggest that the activated PF beads are applicable to the adsorption and recovery of VOC gases. Monolayer adsorption may limit the VOC adsorption with activated PF beads because the adsorption isotherms were better fitted with the Langmuir model. Bamboo tar is shown to be a good replacement for the phenolic compounds from decomposition of petroleum to form activated phenol-formaldehyde (PF) beads. Toluene adsorption tests suggest that the activated PF beads have potential to adsorb and recover VOC gases. Nevertheless, due to the low specific surface area of the activated PF beads from bamboo tar, a further enhancement in both meso- and microporosity is needed in the future experiments. The experimental data provide a contribution to better understanding the possibility of resource recovery of waste agricultural by-products and their potential application in environment protection.

  19. 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.

  20. Recovering the reptation dynamics of polymer melts in dissipative particle dynamics simulations via slip-springs.

    Science.gov (United States)

    Langeloth, Michael; Masubuchi, Yuichi; Böhm, Michael C; Müller-Plathe, Florian

    2013-03-14

    We report a multi-chain approach for dissipative particle dynamics where the uncrossability constraints of polymer chains are mimicked by temporary cross-links, so-called slip-springs. The conformational statistics of the chains are not affected by the introduction of slip-springs. Dynamical properties such as mean square displacements, diffusion coefficient, and longest relaxation time are in good agreement with the results of reptation theory. According to our analysis, the present formalism is 500 times faster and requires 7 times fewer beads than conventional generic polymer models employing Newtonian dynamics and excluded-volume potentials.

  1. 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.

  2. Chemical surface modification of glass beads for the treatment of paper machine process waters

    Energy Technology Data Exchange (ETDEWEB)

    Jradi, Khalil, E-mail: khalil.jradi@uqtr.c [Centre de Recherche en Pates et Papiers, Universite du Quebec a Trois Rivieres, 3351 boul. des forges, C.P. 500, Trois Rivieres, QC, G9A-5H7 (Canada); Daneault, Claude [Canada Research Chair in Value-Added Paper Manufacturing (Canada); Chabot, Bruno [Centre de Recherche en Pates et Papiers, Universite du Quebec a Trois Rivieres, 3351 boul. des forges, C.P. 500, Trois Rivieres, QC, G9A-5H7 (Canada)

    2011-04-29

    Adsorption of detrimental contaminants on a solid sorbent is proposed to remove these contaminants from process waters to increase water recycling and reduce effluent loads in the papermaking industry. A self-assembly process of attaching (covalent grafting) cationic aminosilane molecules to glass beads was investigated. The existence and the hydrolytic stability of self-assembled monolayers and multilayers were confirmed by X-Ray Photoelectron Spectroscopy and contact angle measurements. Effects of reaction time and curing on aminosilane layer structures are also discussed. The curing step after silanization seems to be crucial in the hydrophobization of the quaternary ammonium silane coated onto glass beads, and curing could affect the final chemical structure of the ammonium groups of grafted organosilane. Results indicated that modified glass beads have a strong hydrophobicity, which is attributed to the hydrophobic property of the longest carbon chain grafted onto the glass surface. Adsorption of a model contaminant (stearic acid) onto chemically modified glass beads was determined using colloidal titration. Hydrophobic interactions could be the main driving force involved between the long carbon chains of stearic acid and the carbon chains of the aminosilane layers on glass bead surfaces. Finally, self-assembly processes applied onto glass beads may have two promising applications for papermaking and self-cleaning systems.

  3. Formulation optimization and evaluation of jackfruit seed starch-alginate mucoadhesive beads of metformin HCl.

    Science.gov (United States)

    Nayak, Amit Kumar; Pal, Dilipkumar

    2013-08-01

    The present study deals with the formulation optimization of jackfruit (Artocarpus heterophyllus Lam., family: Moraceae) seed starch (JFSS)-alginate mucoadhesive beads containing metformin HCl through ionotropic gelation using 3(2) factorial design. The effect of sodium alginate to JFSS ratio and CaCl2 concentration on the drug encapsulation efficiency (DEE, %), and cumulative drug release at 10h (R10h, %) was optimized. The optimized beads containing metformin HCl showed DEE of 97.48±3.92%, R10h of 65.70±2.22%, and mean diameter of 1.16±0.11mm. The in vitro drug release from these beads was followed controlled-release (zero-order) pattern with super case-II transport mechanism. The beads were also characterized by SEM and FTIR. The swelling and degradation of these beads were influenced by pH of the test 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 B.V. All rights reserved.

  4. Artocarpus heterophyllus L. seed starch-blended gellan gum mucoadhesive beads of metformin HCl.

    Science.gov (United States)

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

    2014-04-01

    Jackfruit (Artocarpus heterophyllus Lam., family: Moraceae) seed starch (JFSS)-gellan gum (GG) mucoadhesive beads containing metformin HCl were developed through ionotropic gelation technique. The effect of GG to JFSS ratio and CaCl2 concentration on the drug encapsulation efficiency (DEE, %) and cumulative drug release at 10h (R10h, %) was optimized and analyzed using response surface methodology based on 3(2) factorial design. The optimized JFSS-GG beads containing metformin HCl showed DEE of 92.67±4.46%, R10h of 61.30±2.37%, and mean diameter of 1.67±0.27 mm. The optimized beads showed pH-dependent swelling and mucoadhesivity with the goat intestinal mucosa. The in vitro drug release from all these JFSS-GG beads containing metformin HCl was followed zero-order pattern (R(2)=0.9907-0.9975) with super case-II transport mechanism over a period of 10 h. The beads were also characterized by SEM and FTIR. The optimized JFSS-GG beads containing metformin HCl exhibited significant hypoglycemic effect in alloxan-induced diabetic rats over prolonged period after oral administration. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Blends of jackfruit seed starch-pectin in the development of mucoadhesive beads containing metformin HCl.

    Science.gov (United States)

    Nayak, Amit Kumar; Pal, Dilipkumar

    2013-11-01

    In this work, calcium pectinate-jackfruit (Artocarpus heterophyllus Lam.) seed starch (JFSS) mucoadhesive beads containing metformin HCl were developed through ionotropic-gelation. Effects of pectin and JFSS amounts on drug encapsulation efficiency (DEE), and cumulative drug release after 10 h (R10 h) were optimized using 3(2) factorial design. The optimized calcium pectinate-JFSS beads containing metformin HCl showed DEE of 94.11 ± 3.92%, R10 h of 48.88 ± 2.02%, and mean diameter of 2.06 ± 0.20 mm. The in vitro drug release from these beads was followed controlled-release (zero-order) pattern with super case-II transport mechanism. The beads were also characterized by SEM and FTIR. The pH of test mediums was found critical for swelling and mucoadhesion of these beads. The optimized calcium pectinate-JFSS beads also exhibited good mucoadhesivity and significant hypoglycemic effect in alloxan-induced diabetic rats over prolonged period after oral administration. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Using a laser source to measure the refractive index of glass beads and Debye theory analysis.

    Science.gov (United States)

    Li, Shui-Yan; Qin, Shuang; Li, Da-Hai; Wang, Qiong-Hua

    2015-11-20

    Using a monochromatic laser beam to illuminate a homogeneous glass bead, some rainbows will appear around it. This paper concentrates on the study of the scattering intensity distribution and the method of measuring the refractive index for glass beads based on the Debye theory. It is found that the first rainbow due to the scattering superposition of backward light of the low-refractive-index glass beads can be explained approximately with the diffraction, the external reflection plus the one internal reflection, while the second rainbow of high-refractive-index glass beads is due to the contribution from the diffraction, the external reflection, the direct transmission, and the two internal reflections. The scattering intensity distribution is affected by the refractive index, the radius of the glass bead, and the incident beam width. The effects of the refractive index and the glass bead size on the first and second minimum deviation angle position are analyzed in this paper. The results of the measurements agree very well with the specifications.

  7. Calcium alginate encapsulated Ni/Fe nanoparticles beads for simultaneous removal of Cu (II) and monochlorobenzene.

    Science.gov (United States)

    Kuang, Ye; Du, Jianhua; Zhou, Rongbing; Chen, Zuliang; Megharaj, Mallavarapu; Naidu, Ravendra

    2015-06-01

    Calcium alginate encapsulated Ni/Fe bimetallic nanoparticles beads (CA-Ni/Fe beads) were synthesized to simultaneously remove Cu (II) and monochlorobenzene (MCB) from aqueous solution. SEM, EDS, and XRD analyses confirmed that Ni/Fe bimetallic nanoparticles were not oxidized and successfully encapsulated by calcium alginate (CA). The experiments showed that the encapsulation process improved the simultaneous removal efficiency of Cu (II) and MCB, from 83.9% to 86.7% for Cu (II) and 94.7% to 99.1% for MCB compared with bare Ni/Fe nanoparticles after 120min treatment. Furthermore, the removal efficiency of Cu (II) and MCB increased with higher temperature, calcium alginate: Ni/Fe ratios and pH. Pseudo-second-order model for adsorption and pseudo-first-order model for the reduction process fitted the simultaneous removal of Cu (II) and MCB using CA-Ni/Fe beads. Based on the above results, it could be concluded that the simultaneous removal was a two-step process: firstly, the adsorption of Cu (II) and MCB on the CA-Ni/Fe beads; and secondly, reduction of Cu (II) and dehalogenation of MCB by Ni/Fe in CA-Ni/Fe beads. Finally, the efficiency of regenerated CA-Ni/Fe beads was tested using synthesized wastewater which showed a satisfactory removal efficiency of Cu (II) and MCB maintained at 83.8% and 91.7% after three times' regeneration. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Passive detection of Pb in water using rock phosphate agarose beads.

    Science.gov (United States)

    Edenborn, Harry M; Howard, Bret H; Sams, James I; Vesper, Dorothy J; Edenborn, Sherie L

    2017-08-15

    In this study, passive detectors for Pb were prepared by immobilizing powdered rock phosphate in agarose beads. Rock phosphate has been used to treat Pb-contaminated waters and soil by fixing the metal as an insoluble pyromorphite mineral. Under lab conditions, Pb was rapidly adsorbed from aqueous solution by the beads over time, consistent with the acidic dissolution of rock phosphate, the precipitation of pyromorphite within the pore space of the agarose gel matrix, and surface exchange reactions. Net accumulation of Pb occurred when beads were exposed to simulated periodic releases of Pb over time. Under field conditions, beads in mesh bags were effective at detecting dissolved Pb being transported as surface runoff from a site highly contaminated with Pb. Rates of Pb accumulation in beads under field conditions appeared to be correlated with the frequency of storm events and total rainfall. The rock phosphate agarose bead approach could be an inexpensive way to carry out source-tracking of Pb pollution, to verify the successful remediation of sites with Pb-contaminated soil, and to routinely monitor public water systems for potential Pb contamination. Published by Elsevier B.V.

  9. 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.

  10. Removal of radionuclide Sr{sup 2+} ions from aqueous solution using synthesized magnetic chitosan beads

    Energy Technology Data Exchange (ETDEWEB)

    Chen Yuwei [Laboratory of Environmental Technology, INET, Tsinghua University, Beijing 100084 (China); Wang Jianlong, E-mail: wangjl@tsinghua.edu.cn [Laboratory of Environmental Technology, INET, Tsinghua University, Beijing 100084 (China); Beijing Key Laboratory of Fine Ceramics, INET, Tsinghua University, Beijing 100084 (China)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer A novel magnetic chitosan beads were prepared and applied for removing Sr{sup 2+}. Black-Right-Pointing-Pointer The maximum adsorption capacity (q{sub m}) of Sr{sup 2+} was calculated to be 11.58 mg/g using the Langmuir isotherm. Black-Right-Pointing-Pointer The FT-IR study revealed that -NH{sub 2} was mainly involved in Sr{sup 2+} sorption. - Abstract: Strontium-90 is one of the main fission products, existing in the radioactive wastes produced in nuclear power plant. In this paper, a novel magnetic chitosan beads were synthesized, characterized and applied for removal of Sr{sup 2+} ions from aqueous solution. The SEM analysis indicated that the magnetic beads were in regular spherical geometry with about 1 mm diameter. The XRD and EDS analysis revealed that the chitosan beads were magnetic and can be used for the magnetic separation. The influencing factors of Sr{sup 2+} sorption onto magnetic chitosan beads were studied, including contact time, initial pH value, initial Sr{sup 2+}concentration and sorbent dosage. The maximum adsorption capacity (q{sub m}) of Sr{sup 2+} was calculated to be 11.58 mg/g using the Langmuir isotherm. The kinetic data were analyzed by intra particle diffusion model. The FT-IR study revealed that -NH{sub 2} was mainly involved in Sr{sup 2+} sorption by magnetic chitosan beads.

  11. Reproducibility, Reliability, and Validity of Fuchsin-Based Beads for the Evaluation of Masticatory Performance.

    Science.gov (United States)

    Sánchez-Ayala, Alfonso; Farias-Neto, Arcelino; Vilanova, Larissa Soares Reis; Costa, Marina Abrantes; Paiva, Ana Clara Soares; Carreiro, Adriana da Fonte Porto; Mestriner-Junior, Wilson

    2016-08-01

    Rehabilitation of masticatory function is inherent to prosthodontics; however, despite the various techniques for evaluating oral comminution, the methodological suitability of these has not been completely studied. The aim of this study was to determine the reproducibility, reliability, and validity of a test food based on fuchsin beads for masticatory function assessment. Masticatory performance was evaluated in 20 dentate subjects (mean age, 23.3 years) using two kinds of test foods and methods: fuchsin beads and ultraviolet-visible spectrophotometry, and silicone cubes and multiple sieving as gold standard. Three examiners conducted five masticatory performance trials with each test food. Reproducibility of the results from both test foods was separately assessed using the intraclass correlation coefficient (ICC). Reliability and validity of fuchsin bead data were measured by comparing the average mean of absolute differences and the measurement means, respectively, regarding silicone cube data using the paired Student's t-test (α = 0.05). Intraexaminer and interexaminer ICC for the fuchsin bead values were 0.65 and 0.76 (p masticatory performance were good and excellent, respectively; however, the reliability and validity were low, because fuchsin beads do not measure the grinding capacity of masticatory function as silicone cubes do; instead, this test food describes the crushing potential of teeth. Thus, the two kinds of test foods evaluate different properties of masticatory capacity, confirming fushsin beads as a useful tool for this purpose. © 2015 by the American College of Prosthodontists.

  12. Porous bioceramic bead prepared by calcium phosphate with sodium alginate gel and PE powder

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Y.C. [Department of Orthopaedic Surgery, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan (China); Ho, M.L.; Wu, S.C. [Department of Physiology, Kaohsiung Medical University, 100, Shih-Chuan 1st Rd, Kaohsiung 807, Taiwan (China); Hsieh, H.S. [Faculty of Medicinal and Applied Chemistry, Kaohsiung Medical University, 100, Shih-Chuan 1st Rd, Kaohsiung 807, Taiwan (China); Wang, C.K. [Faculty of Medicinal and Applied Chemistry, Kaohsiung Medical University, 100, Shih-Chuan 1st Rd, Kaohsiung 807, Taiwan (China)], E-mail: ckwang@kmu.edu.tw

    2008-08-01

    The porous calcium phosphate beads were made by an alginate-interacting Ca ions mechanism on addition of a pore-forming polyethylene (PE) powder at 1250 deg. C sintering. The nature of the powders and porous beads were analyzed through X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR) and heavy metal analysis by inductively coupled plasma-optical emission spectroscopy (ICP-OES). The porous beads size and the pore microstructure characteristics were determined using scanning electron microscopy (SEM). Beside, the porosity analysis was evaluated out using an Archimedes' principle and mercury porosimetry. Then, the sodium ampicillin was penetrated/adsorbed onto calcium-deficient hydroxyapatite porous beads, and was subsequently released in PBS. No matter whether the raw material was HAp, TCP or biphase, the Ca{sub 9}(HPO{sub 4})(PO{sub 4}){sub 5}OH phase (CDHA) was formed only after sintering. Porous beads of various calcium phosphates with different sizes (0.9-1.1 mm) and pore size groups (60-120 {mu}m and lower than 10 {mu}m) were appeared. The release kinetics of sodium ampicillin from these porous beads have indicated the possibility of using these materials as possible carriers for drug delivery.

  13. Removal and recovery of uranium (VI) from aqueous solutions by immobilized Aspergillus niger powder beads.

    Science.gov (United States)

    Ding, De-Xin; Tan, Xiang; Hu, Nan; Li, Guang-Yue; Wang, Yong-Dong; Tan, Yan

    2012-11-01

    The immobilized Aspergillus niger powder beads were obtained by entrapping nonviable A. niger powder into Ca-alginate gel. The effects of pH, contact time, initial uranium (VI) concentration and biomass dosage on the biosorption of uranium (VI) onto the beads from aqueous solutions were investigated in a batch system. Biosorption equilibrium data were agreeable with Langmuir isotherm model and the maximum biosorption capacity of the beads for uranium (VI) was estimated to be 649.4 mg/g at 30 °C. The biosorption kinetics followed the pseudo-second-order model and intraparticle diffusion equation. The variations in enthalpy (26.45 kJ/mol), entropy (0.167 kJ/mol K) and Gibbs free energy were calculated from the experimental data. SEM and EDS analysis indicated that the beads have strong adsorption capability for uranium (VI). The adsorbed uranium (VI) on the beads could be released with HNO(3) or HCl. The results showed that the immobilized A. niger powder beads had great potential for removing and recovering uranium (VI) from aqueous solutions.

  14. Network formation and gelation in telechelic star polymers.

    Science.gov (United States)

    Wadgaonkar, Indrajit; Chatterji, Apratim

    2017-02-28

    We investigate the efficiency of gelation and network formation in telechelic star polymer melt, where the tips of polymer arms are dipoles while the rest of the monomers are uncharged. Our work is motivated by the experimental observations [A. Kulkarni et al., Macromolecules 48, 6580 (2015)] in which rheological studies of telechelic star polymers of poly-(L-lactide), a bio-degradable polymer, showed a drastic increase in elastic properties (up to 2000 times) compared to corresponding star polymers without the telechelic arm ends. In contrast to previous studies, we avoid using effective attractive Lennard-Jones potentials or dipolar potentials to model telechelic interactions. Instead we use explicit Coulomb positive and negative charges at the tip of polymer-arms of our bead-spring model of star polymers. By our simulations we show that the dipoles at the tip of star arms aggregate together to form clusters of dipoles. Each cluster has contributions from several stars, and in turn each star contributes to several clusters. Thus the entire polymer melt forms a connected network. Network forming tendencies decrease with a decrease of the value of the effective charge constituting the dipole: this can be experimentally realized by choosing a different ionomer for the star tip. We systematically varied the value of dipole charges, the fraction of star-arms with dipoles at the tip, and the length of the arms. The choice of explicit charges in our calculations enables us to make better quantitative predictions about the onset of gelation; moreover we get qualitatively distinct results about structural organization of dipoles within a dipole-cluster.

  15. 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.

  16. Characterizing Reactivity to Onchocerca volvulus Antigens in Multiplex Bead Assays.

    Science.gov (United States)

    Feeser, Karla R; Cama, Vitaliano; Priest, Jeffrey W; Thiele, Elizabeth A; Wiegand, Ryan E; Lakwo, Thomson; Feleke, Sindew M; Cantey, Paul T

    2017-09-01

    Multiplex bead assays (MBAs) may provide a powerful integrated tool for monitoring, evaluation, and post-elimination surveillance of onchocerciasis and co-endemic diseases; however, the specificity and sensitivity of Onchocerca volvulus antigens have not been characterized within this context. An MBA was developed to evaluate three antigens (OV-16, OV-17, and OV-33) for onchocerciasis. Receiver operating characteristics (ROC) analyses were used to characterize antigen performance using a panel of 610 specimens: 109 O. volvulus-positive specimens, 426 non-onchocerciasis controls with filarial and other confirmed parasitic infection, and 75 sera from patients with no other parasitic infection. The IgG and IgG4 assays for OV-16 demonstrated sensitivities of 95.4% and 96.3%, and specificities of 99.4% and 99.8%, respectively. The OV-17 IgG and IgG4 assays had sensitivities of 86.2% and 76.1% and specificities of 79.2% and 82.8%. For OV-33, the IgG and IgG4 assays had sensitivities of 90.8% and 96.3%, and specificities of 96.8% and 98.6%. The OV-16 IgG4-based MBA had the best assay characteristics, followed by OV-33 IgG4. The OV-16 IgG4 assay would be useful for monitoring and evaluation using the MBA platform. Further evaluations are needed to review the potential use of OV-33 as a confirmatory test in the context of program evaluations.

  17. Magnetic bead based immunoassay for autonomous detection of toxins.

    Science.gov (United States)

    Kwon, Youngeun; Hara, Christine A; Knize, Mark G; Hwang, Mona H; Venkateswaran, Kodumudi S; Wheeler, Elizabeth K; Bell, Perry M; Renzi, Ronald F; Fruetel, Julie A; Bailey, Christopher G

    2008-11-15

    We are developing an automated system for the simultaneous, rapid detection of a group of select agents and toxins in the environment. To detect toxins, we modified and automated an antibody-based approach previously developed for manual medical diagnostics that uses fluorescent eTag 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 through a cleavable linkage. Aqueous samples are incubated with the mixture of antibodies along with streptavidin-coated magnetic beads and a photoactive porphyrin complex. In the presence of antigen, a molecular complex is formed where the cleavable linkage is held in proximity to the photoactive group. Upon excitation at 680 nm, free radicals are generated, which diffuse and cleave the linkage, releasing the eTags. Released eTags are analyzed using capillary gel electrophoresis with laser-induced fluorescence detection. Limits of detection for ovalbumin and botulinum toxoid individually were 4 (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 in a flow-through format with higher LODs of 32 ng/mL (or 640 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.

  18. 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

    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......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...

  19. 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.

  20. Magnetic/pH-sensitive κ-carrageenan/sodium alginate hydrogel nanocomposite beads: preparation, swelling behavior, and drug delivery.

    Science.gov (United States)

    Mahdavinia, Gholam Reza; Rahmani, Zeinab; Karami, Shiva; Pourjavadi, Ali

    2014-01-01

    This work describes the preparation of magnetic and pH-sensitive beads based on κ-carrageenan and sodium alginate for use as drug-targeting carriers. Physical cross-linking using K(+)/Ca(2+) ions was applied to obtain ionic cross-linked magnetic hydrogel beads. The produced magnetite beads were thoroughly characterized by TEM, SEM/EDS, XRD, FTIR, and VSM techniques. While the water absorbency (WA) of magnetic beads was enhanced by increasing the weight ratio of κ-carrageenan, introducing magnetic nanoparticles caused a decrease in WA capacity from 15.4 to 6.3 g/g. Investigation on the swelling of the hydrogel beads in NaCl, KCl, and CaCl2 solutions revealed the disintegration of beads depending on the composition of hydrogel beads and the type of metal cations in swelling media. The swelling ratio of beads indicated pH-dependent properties with maximum water absorbing at pH 7.4. Also, it was found that the strength of pH-sensitivity of magnetic beads was low for beads with the high content of carrageenan component. The in vitro drug release studies from hydrogels exhibited significant behaviors on the subject of physiological-simulated pH values and external magnetic fields. The maximum cumulative releases obtained were 98 and 43% at pH values 7.4 and 1.2, respectively. The Introducing magnetite nanoparticles influenced the cumulative release of drug.

  1. Rhenium-coated glass beads for intracolonic administration attenuate TNBS-induced colitis in mice: Proof-of-Concept Study.

    Science.gov (United States)

    Siczek, Krzysztof; Zatorski, Hubert; Pawlak, Wojciech; Fichna, Jakub

    2015-01-01

    In search for novel effective treatments in inflammatory bowel diseases, a new strategy employing glass beads coated with rhenium nanolayer has been developed and validated in the mouse model of 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis. Briefly, mice were randomly divided into 5 experimental groups: control (vehicle alone, Group 1); control treated with rhenium-coated glass beads (Group 2); TNBS (Group 3); TNBS treated with rhenium-coated glass beads (Group 4); and TNBS treated with uncoated glass beads (Group 5). Mice from Group 2, 4 and 5 were treated with respective beads (once daily, 5 beads / animal, i.c.) between D3-D6 post-TNBS/vehicle and evaluation of colonic damage was performed on D7, based on macroscopic scoring and clinical parameters. Severe colonic inflammation developed in post-TNBS mice (Group 3) [P glass beads (Group 4) [P glass beads had any effect in control animals (Group 2), nor uncoated glass beads influenced TNBS-induced colitis (Group 5). In conclusion, a novel and attractive strategy for the treatment of colonic inflammation has been proposed; therapy with rhenium-coated glass beads already proved effective in the mouse model of TNBS-induced colitis, now requires further characterization in clinical conditions.

  2. The development, physicochemical characterisation and in vitro drug release studies of pectinate gel beads containing Thai mango seed kernel extract.

    Science.gov (United States)

    Nithitanakool, Saruth; Pithayanukul, Pimolpan; Bourgeois, Sandrine; Fessi, Hatem; Bavovada, Rapepol

    2013-06-03

    Pectinate gel beads containing Thai mango seed kernel extract (MSKE, cultivar 'Fahlun') were developed and characterised for the purpose of colon-targeted delivery. The MSKE-loaded pectinate beads were prepared using ionotropic gelation with varying pectin-to-MSKE ratios, MSKE concentrations, and concentrations of two cross-linkers (calcium chloride and zinc acetate). The formulated beads were spherical in shape and ranged in size between 1.13 mm and 1.88 mm. Zinc-pectinate (ZPG) beads containing high amounts of MSKE showed complete entrapment efficiency (EE) of MSKE (100%), while calcium-pectinate (CPG) beads demonstrated 70% EE. The in vitro release tests indicated that MSKE-loaded CPG beads were unstable in both simulated gastric medium (SGM) and simulated intestinal medium (SIM), while MSKE-loaded ZPG beads were stable in SIM but unable to prevent the release of MSKE in SGM. The protection of ZPG beads with gastro-resistant capsules (Eudragit® L 100-55) resulted in stability in both SGM and SIM; they disintegrated immediately in simulated colonic medium containing pectinolytic enzymes. MSKE-loaded ZPG beads were stable at 4, 25 and 45 °C during the study period of four months. The present study revealed that ZPG beads in enteric-coated capsules might be a promising carrier for delivering MSKE to the colon.

  3. The Development, Physicochemical Characterisation and in Vitro Drug Release Studies of Pectinate Gel Beads Containing Thai Mango Seed Kernel Extract

    Directory of Open Access Journals (Sweden)

    Hatem Fessi

    2013-06-01

    Full Text Available Pectinate gel beads containing Thai mango seed kernel extract (MSKE, cultivar ‘Fahlun’ were developed and characterised for the purpose of colon-targeted delivery. The MSKE-loaded pectinate beads were prepared using ionotropic gelation with varying pectin-to-MSKE ratios, MSKE concentrations, and concentrations of two cross-linkers (calcium chloride and zinc acetate. The formulated beads were spherical in shape and ranged in size between 1.13 mm and 1.88 mm. Zinc-pectinate (ZPG beads containing high amounts of MSKE showed complete entrapment efficiency (EE of MSKE (100%, while calcium-pectinate (CPG beads demonstrated 70% EE. The in vitro release tests indicated that MSKE-loaded CPG beads were unstable in both simulated gastric medium (SGM and simulated intestinal medium (SIM, while MSKE-loaded ZPG beads were stable in SIM but unable to prevent the release of MSKE in SGM. The protection of ZPG beads with gastro-resistant capsules (Eudragit® L 100-55 resulted in stability in both SGM and SIM; they disintegrated immediately in simulated colonic medium containing pectinolytic enzymes. MSKE-loaded ZPG beads were stable at 4, 25 and 45 °C during the study period of four months. The present study revealed that ZPG beads in enteric-coated capsules might be a promising carrier for delivering MSKE to the colon.

  4. Evaluation of the Effect of Psyllium on the Viability of Lactobacillus Acidophilus in Alginate-Polyl Lysine Beads.

    Science.gov (United States)

    Esmaeilzadeh, Jaleh; Nazemiyeh, Hossein; Maghsoodi, Maryam; Lotfipour, Farzaneh

    2016-09-01

    Purpose: Psylliumseeds are used in traditional herbal medicine to treat various disorders. Moreover, as a soluble fiber, psyllium has potential to stimulate bacterial growth in digestive system. We aimed to substitute alkali-extractable polysaccharides of psyllium for alginate in beads with second coat of poly-l-lysine to coat Lactobacillus acidophilus. Methods: Beads were prepared using extrusion technique. Poly-l-lysine as second coat was incorporated on optimum alginate/psyllium beads using immersion technique. Beads were characterized in terms of size, encapsulation efficiency, integrity and bacterial survival in harsh conditions. Results: Beads with narrow size distribution ranging from 1.85 ± 0.05 to 2.40 ± 0.18 mm with encapsulation efficiency higher than 96% were achieved. Psyllium concentrations in beads did not produce constant trend in bead sizes. Surface topography by SEM showed that substitution of psyllium enhanced integrity of obtained beads. Psyllium successfully protected the bacteria against acidic condition and lyophilization equal to alginate in the beads. Better survivability with beads of alginate/psyllium-poly-l-lysine was achieved with around 2 log rise in bacterial count in acid condition compared to the corresponding single coat beads. Conclusion: Alginate/psyllium (1:2) beads with narrow size distribution and high encapsulation efficiency of the bacteria have been achieved. Presence of psyllium produced a much smoother and integrated surface texture for the beads with sufficient protection of the bacteria against acidic condition as much as alginate. Considering the health benefits of psyllium and its prebiotic activity, psyllium can be beneficially replaced in part for alginate in probiotic coating.

  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. Dual-crosslinked poly(vinyl alcohol)/sodium alginate/silver nanocomposite beads - A promising antimicrobial material.

    Science.gov (United States)

    Narayanan, Kannan Badri; Han, Sung Soo

    2017-11-01

    In this paper, we report the immobilization of borate-stabilized silver nanoparticles (AgNPs) as nanofillers in dual-crosslinked polymers comprised of poly(vinyl alcohol) (PVA) and sodium alginate (SA) at different ratios. Ionic-crosslinking using Ca(2+) ions and physical-crosslinking by freeze-thawing were used to entrap silver nanoparticles in the prepared PVA/SA/AgNPs nanocomposite beads. These polymeric nanocomposites were characterized by UV-Vis, XRD, FE-SEM, FT-IR, TGA, and using rheological and swelling properties. The antibacterial activities of these PVA/SA/AgNPs nanocomposites were evaluated against Escherichia coli O157: H7, which causes escherichiosis through contaminated food and water. The results obtained indicated that PVA/SA/AgNPs nanocomposite formed with a ratio 10/90 of PVA to SA (formulation F5) exhibited high bactericidal activity, with entrapment of AgNPs and had excellent rheological and thermal stabilities. Due to the low cost and effectiveness of these antimicrobial nanocomposites, they have potential as an active food-packaging material for food safety and to extend shelf-life of packaged foods. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Effect of immobilized cells in calcium alginate beads in alcoholic fermentation.

    Science.gov (United States)

    Duarte, Juliana C; Rodrigues, J Augusto R; Moran, Paulo J S; Valença, Gustavo P; Nunhez, José R

    2013-05-30

    Saccharomyces cerevisiae cells were immobilized in calcium alginate and chitosan-covered calcium alginate beads and studied in the fermentation of glucose and sucrose for ethanol production. The batch fermentations were carried out in an orbital shaker and assessed by monitoring the concentration of substrate and product with HPLC. Cell immobilization in calcium alginate beads and chitosan-covered calcium alginate beads allowed reuse of the beads in eight sequential fermentation cycles of 10 h each. The final concentration of ethanol using free cells was 40 g L-1 and the yields using glucose and sucrose as carbon sources were 78% and 74.3%, respectively. For immobilized cells in calcium alginate beads, the final ethanol concentration from glucose was 32.9 ± 1.7 g L-1 with a 64.5 ± 3.4% yield, while the final ethanol concentration from sucrose was 33.5 ± 4.6 g L-1 with a 64.5 ± 8.6% yield. For immobilized cells in chitosan-covered calcium alginate beads, the ethanol concentration from glucose was 30.7 ± 1.4 g L-1 with a 61.1 ± 2.8% yield, while the final ethanol concentration from sucrose was 31.8 ± 6.9 g L-1 with a 62.1 ± 12.8% yield. The immobilized cells allowed eight 10 h sequential reuse cycles to be carried out with stable final ethanol concentrations. In addition, there was no need to use antibiotics and no contamination was observed. After the eighth cycle, there was a significant rupture of the beads making them inappropriate for reuse.

  8. Automated electrotransformation of Escherichia coli on a digital microfluidic platform using bioactivated magnetic beads.

    Science.gov (United States)

    Moore, J A; Nemat-Gorgani, M; Madison, A C; Sandahl, M A; Punnamaraju, S; Eckhardt, A E; Pollack, M G; Vigneault, F; Church, G M; Fair, R B; Horowitz, M A; Griffin, P B

    2017-01-01

    This paper reports on the use of a digital microfluidic platform to perform multiplex automated genetic engineering (MAGE) cycles on droplets containing Escherichia coli cells. Bioactivated magnetic beads were employed for cell binding, washing, and media exchange in the preparation of electrocompetent cells in the electrowetting-on-dieletric (EWoD) platform. On-cartridge electroporation was used to deliver oligonucleotides into the cells. In addition to the optimization of a magnetic bead-based benchtop protocol for generating and transforming electrocompetent E. coli cells, we report on the implementation of this protocol in a fully automated digital microfluidic platform. Bead-based media exchange and electroporation pulse conditions were optimized on benchtop for transformation frequency to provide initial parameters for microfluidic device trials. Benchtop experiments comparing electrotransformation of free and bead-bound cells are presented. Our results suggest that dielectric shielding intrinsic to bead-bound cells significantly reduces electroporation field exposure efficiency. However, high transformation frequency can be maintained in the presence of magnetic beads through the application of more intense electroporation pulses. As a proof of concept, MAGE cycles were successfully performed on a commercial EWoD cartridge using variations of the optimal magnetic bead-based preparation procedure and pulse conditions determined by the benchtop results. Transformation frequencies up to 22% were achieved on benchtop; this frequency was matched within 1% (21%) by MAGE cycles on the microfluidic device. However, typical frequencies on the device remain lower, averaging 9% with a standard deviation of 9%. The presented results demonstrate the potential of digital microfluidics to perform complex and automated genetic engineering protocols.

  9. [XPS analysis of beads formed by fuse breaking of electric copper wire].

    Science.gov (United States)

    Wu, Ying; Meng, Qing-Shan; Wang, Xin-Ming; Gao, Wei; Di, Man

    2010-05-01

    The in-depth composition of beads formed by fuse breaking of the electric copper wire in different circumstances was studied by XPS with Ar+ ion sputtering. In addition, the measured Auger spectra and the calculated Auger parameters were compared for differentiation of the substances of Cu and Cu2O. Corresponding to the sputtering depth, the molten product on a bead induced directly by fuse breaking of the copper wire without cover may be distinguished as three portions: surface layer with a drastic decrease in carbon content; intermediate layer with a gentle change in oxygen content and gradually diminished carbon peak, and consisting of Cu2O; transition layer without Cu2O and with a rapid decrease in oxygen content. While the molten product on a bead formed by fuse breaking of the copper wire after its insulating cover had been burned out may be distinguished as two portions: surface layer with carbon content decreasing quickly; subsurface layer without Cu2O and with carbon and oxygen content decreasing gradually. Thus, it can be seen that there was an obvious interface between the layered surface product and the substrate for the first type of bead, while as to the second type of bead there was no interface. As a result, the presence of Cu2O and the quantitative results can be used to identify the molten product on a bead induced directly by fuse breaking of the copper wire without cover and the molten product on a bead formed by fuse breaking of the cupper wire after its insulating cover had been burned out, as a complementary technique for the judgments of fire cause.

  10. Artificial Intelligence vs. Statistical Modeling and Optimization of Continuous Bead Milling Process for Bacterial Cell Lysis.

    Science.gov (United States)

    Haque, Shafiul; Khan, Saif; Wahid, Mohd; Dar, Sajad A; Soni, Nipunjot; Mandal, Raju K; Singh, Vineeta; Tiwari, Dileep; Lohani, Mohtashim; Areeshi, Mohammed Y; Govender, Thavendran; Kruger, Hendrik G; Jawed, Arshad

    2016-01-01

    For a commercially viable recombinant intracellular protein production process, efficient cell lysis and protein release is a major bottleneck. The recovery of recombinant protein, cholesterol oxidase (COD) was studied in a continuous bead milling process. A full factorial response surface methodology (RSM) design was employed and compared to artificial neural networks coupled with genetic algorithm (ANN-GA). Significant process variables, cell slurry feed rate (A), bead load (B), cell load (C), and run time (D), were investigated and optimized for maximizing COD recovery. RSM predicted an optimum of feed rate of 310.73 mL/h, bead loading of 79.9% (v/v), cell loading OD600nm of 74, and run time of 29.9 min with a recovery of ~3.2 g/L. ANN-GA predicted a maximum COD recovery of ~3.5 g/L at an optimum feed rate (mL/h): 258.08, bead loading (%, v/v): 80%, cell loading (OD600nm): 73.99, and run time of 32 min. An overall 3.7-fold increase in productivity is obtained when compared to a batch process. Optimization and comparison of statistical vs. artificial intelligence techniques in continuous bead milling process has been attempted for the very first time in our study. We were able to successfully represent the complex non-linear multivariable dependence of enzyme recovery on bead milling parameters. The quadratic second order response functions are not flexible enough to represent such complex non-linear dependence. ANN being a summation function of multiple layers are capable to represent complex non-linear dependence of variables in this case; enzyme recovery as a function of bead milling parameters. Since GA can even optimize discontinuous functions present study cites a perfect example of using machine learning (ANN) in combination with evolutionary optimization (GA) for representing undefined biological functions which is the case for common industrial processes involving biological moieties.

  11. 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.

  12. Fingerprinting polymer microarrays.

    Science.gov (United States)

    Tourniaire, Guilhem; Diaz-Mochon, Juan J; Bradley, Mark

    2009-08-01

    The incubation of "polymer microarrays" with labelled proteins and carbohydrates demonstrated polymer selective binding, giving an approach to cellular fingerprinting and offering a possible alternative to current arraying platforms for partitioning and analysis of complex cellular components.

  13. Mechanical Properties of Polymers.

    Science.gov (United States)

    Aklonis, J. J.

    1981-01-01

    Mechanical properties (stress-strain relationships) of polymers are reviewed, taking into account both time and temperature factors. Topics include modulus-temperature behavior of polymers, time dependence, time-temperature correspondence, and mechanical models. (JN)

  14. 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...

  15. Anion exchange polymer electrolytes

    Science.gov (United States)

    Kim, Yu Seung; Kim, Dae Sik

    2015-06-02

    Anion exchange polymer electrolytes that include guanidinium functionalized polymers may be used as membranes and binders for electrocatalysts in preparation of anodes for electrochemical cells such as solid alkaline fuel cells.

  16. Polymer dynamics from synthetic polymers to proteins

    Indian Academy of Sciences (India)

    Starting from the standard model of polymer motion - the Rouse model - we briefly present some key experimental results on the mesoscopic dynamics of polymer systems. We touch the role of topological confinement as expressed in the reptation model and discuss in some more detail processes limiting the confinement.

  17. POLYMER CONCRETE CREEP

    OpenAIRE

    Yu. М. Borisov; I. S. Surovtsev; Yu. B. Potapov

    2012-01-01

    Problem statement. It is well known that creep is the tendency of a solid material to move slowly or deform permanently under the influence of stresses. The aim of the paper is to study the process of creep in polymer concretes. Results and conclusions. It is shown that creep in polymer concrete occurs according to the same pattern as in many other polymer composites with the elastic core. Equations which indirectly es-tablish the relation between complete deformations of polymer concrete, in...

  18. Modeling semiflexible polymer networks

    OpenAIRE

    Broedersz, Chase P.; MacKintosh, Fred C.

    2014-01-01

    Here, we provide an overview of theoretical approaches to semiflexible polymers and their networks. Such semiflexible polymers have large bending rigidities that can compete with the entropic tendency of a chain to crumple up into a random coil. Many studies on semiflexible polymers and their assemblies have been motivated by their importance in biology. Indeed, crosslinked networks of semiflexible polymers form a major structural component of tissue and living cells. Reconstituted networks o...

  19. Biopolymers Versus Synthetic Polymers

    OpenAIRE

    Florentina Adriana Cziple; António J. Velez Marques

    2008-01-01

    This paper present an overview of important synthetic and natural polymers with emphasis on polymer structure, the chemistry of polymer formation. an introduction to polymer characterization. The biodegradation process can take place aerobically and anaerobically with or without the presence of light. These factors allow for biodegradation even in landfill conditions which are normally inconducive to any degradation. The sheeting used to make these packages differs...

  20. Thermosetting Phthalocyanine Polymers

    Science.gov (United States)

    Fohlen, G.; Parker, J.; Achar, B.

    1985-01-01

    Group of phthalocyanine polymers resist thermal degradation. Polymers expected semiconducting. Principal applications probably in molded or laminated parts that have to withstand high temperatures. Polymers made from either of two classes of monomer: Bisphthalonitriles with imide linkages or Bisphthalonitriles with ester-imide linkages.

  1. Modeling semiflexible polymer networks

    NARCIS (Netherlands)

    Broedersz, C.P.; MacKintosh, F.C.

    2014-01-01

    This is an overview of theoretical approaches to semiflexible polymers and their networks. Such semiflexible polymers have large bending rigidities that can compete with the entropic tendency of a chain to crumple up into a random coil. Many studies on semiflexible polymers and their assemblies have

  2. Aerogel / Polymer Composite Materials

    Science.gov (United States)

    Williams, Martha K. (Inventor); Smith, Trent M. (Inventor); Fesmire, James E. (Inventor); Roberson, Luke B. (Inventor); Clayton, LaNetra M. (Inventor)

    2017-01-01

    The invention provides new composite materials containing aerogels blended with thermoplastic polymer materials at a weight ratio of aerogel to thermoplastic polymer of less than 20:100. The composite materials have improved thermal insulation ability. The composite materials also have better flexibility and less brittleness at low temperatures than the parent thermoplastic polymer materials.

  3. Pseudomonas aeruginosa Aggregate Formation in an Alginate Bead Model System Exhibits In Vivo-Like Characteristics.

    Science.gov (United States)

    Sønderholm, Majken; Kragh, Kasper Nørskov; Koren, Klaus; Jakobsen, Tim Holm; Darch, Sophie E; Alhede, Maria; Jensen, Peter Østrup; Whiteley, Marvin; Kühl, Michael; Bjarnsholt, Thomas

    2017-05-01

    Alginate beads represent a simple and highly reproducible in vitro model system for diffusion-limited bacterial growth. In this study, alginate beads were inoculated with Pseudomonas aeruginosa and followed for up to 72 h. Confocal microscopy revealed that P. aeruginosa formed dense clusters similar in size to in vivo aggregates observed ex vivo in cystic fibrosis lungs and chronic wounds. Bacterial aggregates primarily grew in the bead periphery and decreased in size and abundance toward the center of the bead. Microsensor measurements showed that the O2 concentration decreased rapidly and reached anoxia ∼100 μm below the alginate bead surface. This gradient was relieved in beads supplemented with NO3- as an alternative electron acceptor allowing for deeper growth into the beads. A comparison of gene expression profiles between planktonic and alginate-encapsulated P. aeruginosa confirmed that the bacteria experienced hypoxic and anoxic growth conditions. Furthermore, alginate-encapsulated P. aeruginosa exhibited a lower respiration rate than the planktonic counterpart and showed a high tolerance toward antibiotics. The inoculation and growth of P. aeruginosa in alginate beads represent a simple and flexible in vivo-like biofilm model system, wherein bacterial growth exhibits central features of in vivo biofilms. This was observed by the formation of small cell aggregates in a secondary matrix with O2-limited growth, which was alleviated by the addition of NO3- as an alternative electron acceptor, and by reduced respiration rates, as well as an enhanced tolerance to antibiotic treatment.IMPORTANCEPseudomonas aeruginosa has been studied intensively for decades due to its involvement in chronic infections, such as cystic fibrosis and chronic wounds, where it forms biofilms. Much research has been dedicated to biofilm formation on surfaces; however, in chronic infections, most biofilms form small aggregates of cells not attached to a surface, but embedded in host

  4. Distribution and biophysical processes of beaded streams in Arctic permafrost landscapes

    Science.gov (United States)

    Arp, C. D.; Whitman, M. S.; Jones, B. M.; Grosse, G.; Gaglioti, B. V.; Heim, K. 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 one Arctic coastal plain 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. The comparisons 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 insulate 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 that range from 0.7 to 1.6 m. In the summer, some pools thermally stratify, which reduces permafrost thaw and maintains cold-water 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 0.01 to 0.1 m s-1

  5. Poly(ethylene glycol dimethacrylate-n-vinyl imidazole) beads for heavy metal removal

    Energy Technology Data Exchange (ETDEWEB)

    Kara, Ali; Uzun, Lokman; Besirli, Necati; Denizli, Adil

    2004-01-30

    Poly(ethylene glycol dimethacrylate-n-vinyl imidazole) [poly(EGDMA-VIM)] hydrogel (average diameter 150-200 {mu}m) was prepared by copolymerizing ethylene glycol dimethacrylate (EGDMA) with n-vinyl imidazole (VIM). The copolymer hydrogel bead composition was characterized by elemental analysis and found to contain 5 EGDMA monomer units each VIM monomer unit. Poly(EGDMA-VIM) beads had a specific surface area of 59.8 m{sup 2}/g. Poly(EGDMA-VIM) beads were characterized by swelling studies and scanning electron microscopy (SEM). These poly(EGDMA-VIM) beads with a swelling ratio of 78% were used for the heavy metal removal studies. Chelation capacity of the beads for the selected metal ions, i.e., Cd(II), Hg(II) and Pb(II) were investigated in aqueous media containing different amounts of these ions (10-750 mg/l) and at different pH values (3.0-7.0). Chelation rate was very fast. The maximum chelation capacities of the poly(EGDMA-VIM) beads were 69.4 mg/g for Cd(II), 114.8 mg/g for Pb(II) and 163.5 mg/g for Hg(II). The affinity order on molar basis was observed as follows: Hg(II)>Cd(II)>Pb(II). Chelation behavior of heavy metal ions could be modelled using both the Langmuir and Freundlich isotherms. pH significantly affected the chelation capacity of VIM incorporated beads. Chelation of heavy metal ions from synthetic wastewater was also studied. The chelation capacities are 45.6 mg/g for Cd(II), 74.2 mg/g for Hg(II) and 92.5 mg/g for Pb(II) at 0.5 mmol/l initial metal concentration. Regeneration of the chelating-beads was easily performed with 0.1 M HNO{sub 3}. These features make poly(EGDMA-VIM) beads potential candidate adsorbent for heavy metal removal.

  6. 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

  7. Glass beads and Ge-doped optical fibres as thermoluminescence dosimeters for small field photon dosimetry.

    Science.gov (United States)

    Jafari, S M; Alalawi, A I; Hussein, M; Alsaleh, W; Najem, M A; Hugtenburg, R P; Bradley, D A; Spyrou, N M; Clark, C H; Nisbet, A

    2014-11-21

    An investigation has been made of glass beads and optical fibres as novel dosimeters for small-field photon radiation therapy dosimetry. Commercially available glass beads of largest dimension 1.5 mm and GeO2-doped SiO2 optical fibres of 5 mm length and 120 µm diameter were characterized as thermoluminescence dosimeters. Results were compared against Monte-Carlo simulations with BEAMnrc/DOSXYZnrc, EBT3 Gafchromic film, and a high-resolution 2D-array of liquid-filled ionization chambers. Measurements included relative output factors and dose profiles for square-field sizes of 1, 2, 3, 4, and 10 cm. A customized Solid-Water® phantom was employed, and the beads and fibres were placed at defined positions along the longitudinal axis to allow accurate beam profile measurement. Output factors and the beam profile parameters were compared against those calculated by BEAMnrc/DOSXYZnrc. The output factors and field width measurements were found to be in agreement with reference measurements to within better than 3.5% for all field sizes down to 2 cm2 for both dosimetric systems, with the beads showing a discrepancy of no more than 2.8% for all field sizes. The results confirm the potential of the beads and fibres as thermoluminescent dosimeters for use in small photon radiation field sizes.

  8. A hybrid assembly by encapsulation of human cells within mineralised beads for cell therapy.

    Directory of Open Access Journals (Sweden)

    Philippe Dandoy

    Full Text Available BACKGROUND: The design of new technologies for treatment of human disorders such as protein deficiencies is a complex and difficult task. Particularly, the construction of artificial organs, based on the immunoisolation of protein-secreting cells, requires the use of suitable materials which have to be biocompatible with the immunoisolated cells and avoid any inappropriate host response. METHODOLOGY/PRINCIPAL FINDINGS: This work investigates the in vivo behavior of mechanically resistant hybrid beads which can be considered as a model for artificial organ for cell therapy. This hybrid system was designed and fabricated via the encapsulation of living cells (HepG2 within alginate-silica composites. Two types of beads (alginate-silica hybrid (AS or alginate/silica hybrid subsequently covered by an external layer of pure alginate (ASA, with or without HepG2 cells, were implanted into several female Wistar rats. After four weeks, the potential inflammatory local response that might be due to the presence of materials was studied by histochemistry. The results showed that the performance of ASA beads was quite promising compared to AS beads, where less abnormal rat behaviour and less inflammatory cells in histological sections were observed in the case of ASA beads. CONCLUSIONS/SIGNIFICANCE: The current study highlights that alginate-silica composite materials coated with an extra-alginate shell offer much promise in the development of robust implantation devices and artificial organs.

  9. A portable optical reader and wall projector towards enumeration of bio-conjugated beads or cells.

    Directory of Open Access Journals (Sweden)

    Macdara T Glynn

    Full Text Available Measurement of the height of a packed column of cells or beads, which can be direclty related to the number of cells or beads present in a chamber, is an important step in a number of diagnostic assays. For example, haematocrit measurements may rapidly identify anemia or polycthemia. Recently, user-friendly and cost-efficient Lab-on-a-Chip devices have been developed towards isolating and counting cell sub-populations for diagnostic purposes. In this work, we present a low-cost optical module for estimating the filling level of packed magnetic beads within a Lab-on-a-Chip device. The module is compatible with a previously introduced, disposable microfluidic chip for rapid determination of CD4+ cell counts. The device is a simple optical microscope module is manufactured by 3D printing. An objective lens directly interrogates the height of packed beads which are efficiently isolated on the finger-actuated chip. Optionally, an inexpensive, battery-powered Light Emitting Diode may project a shadow of the microfluidic chip at approximately 50-fold magnification onto a nearby surface. The reader is calibrated with the filling levels of known concentrations of paramagnetic beads within the finger actuated chip. Results in direct and projector mode are compared to measurements from a conventional, inverted white-light microscope. All three read-out methods indicate a maximum variation of 6.5% between methods.

  10. 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.

  11. Effects of silica content on the formation and morphology of ENR/PVC/Silica composites beads

    Science.gov (United States)

    Abdullah, Nurul Amni; Tahiruddin, Nordiana Suhada Mohmad; Othaman, Rizafizah

    2017-05-01

    The effects of silica content in preparing silica-filled epoxidized natural rubber/polyvinyl chloride (ENR/PVC) beads were investigated. ENR/PVC matrix blend used was of composition 60% (ENR50) and 40% (PVC) by weight. The matrix blend was then dissolved in tetrahydrofuran (THF) by sol-gel technique prior to addition of silica fume as filler at varying amounts up to 25 wt% of the matrix mass. The composites beads were formed via phase inversion method by dropping the polymeric solution into a non-solvent. The size and shape were improved by adding in an increased amount of silica. Morphological studies showed distinct features of beads' surface in terms of homogeneity of silica particle distribution and presence of agglomerations and voids within the ENR/PVC matrix. Formation of silica network was apparent on the bead at 25 wt% silica content. The bead formation was found to be significantly affected by the silica loading in the ENR/PVC solution.

  12. Microporous novolac-derived carbon beads/sulfur hybrid cathode for lithium-sulfur batteries

    Science.gov (United States)

    Choudhury, Soumyadip; Krüner, Benjamin; Massuti-Ballester, Pau; Tolosa, Aura; Prehal, Christian; Grobelsek, Ingrid; Paris, Oskar; Borchardt, Lars; Presser, Volker

    2017-07-01

    Novolac-derived nanoporous carbon beads were used as conductive matrix for lithium-sulfur battery cathodes. We employed a facile self-emulsifying synthesis to obtain sub-micrometer novolac-derived carbon beads with nanopores. After pyrolysis, the carbon beads showed already a specific surface area of 640 m2 g-1 which was increased to 2080 m2 g-1 after physical activation. The non-activated and the activated carbon beads represent nanoporous carbon with a medium and a high surface area, respectively. This allows us to assess the influence of the porosity on the electrochemical performance of lithium-sulfur battery cathodes. The carbon/sulfur hybrids were obtained from two different approaches of sulfur infiltration: melt-infusion of sulfur (annealing) and in situ formation of sulfur from sodium thiosulfate. The best performance (∼880 mAh gsulfur-1 at low charge rate; 5th cycle) and high performance stability (>600 mAh gsulfur-1 after 100 cycles) were found for the activated carbon beads when using melt infusion of sulfur.

  13. Development of mucoadhesive floating hollow beads of acyclovir with gastroretentive properties.

    Science.gov (United States)

    Svirskis, Darren; Seyfoddin, Ali; Chalabi, Suna; In Kim, Joanne Hye; Langford, Christopher; Painter, Sivani; Al-Kassas, Raida

    2014-08-01

    This study aimed at improving the oral bioavailability of acyclovir (ACV) through incorporating it into gastroretentive dosage form based on floating hollow chitosan beads. Hollow chitosan beads were prepared using a solvent free, ionotropic gelation method. The effect of formulation parameters, including chitosan molecular weight and drug concentration, on bead characteristics was studied. The drug containing formulations had yields >70.5 ± 0.31%. The entrapment efficiencies for the medium molecular weight chitosan formulations (56.29 ± 0.94%-62.75 ± 0.86%) was greater than the high molecular weight chitosan formulation (29.21 ± 0.89%). The density of all formulations was below that of gastric fluid, the greatest density observed was 0.60 ± 0.01 g cm(-3). Unsurprisingly, the formulations were immediate bouyant to different degrees in both pH 1.2 and pH 6.8 media. In addition, the chitosan beads were all seen to swell in pH 1.2 media and demonstrated mucoadhesive properties. A sustained release profile was observed from the chitosan beads, the developed formulations released drug at slower rates than a marketed ACV oral tablet. The developed system has the dual advantages of being gastroretentive, to increase oral bioavailability and releasing drug in a controlled manner, to reduce the required frequency of administration thereby promoting patient adherence.

  14. Appropriate welding conditions of temper bead weld repair for SQV2A pressure vessel steel

    Energy Technology Data Exchange (ETDEWEB)

    Mizuno, R.; Matsuda, F. [NDE Center, Japan Power Engineering and Inspection Corp. (Japan); Brziak, P. [Welding Research Inst. - Industrial Inst. of Slovak Republic (Slovakia); Lomozik, M. [Inst. of Welding (Poland)

    2004-07-01

    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.)

  15. Chitosan derivatives/reduced graphene oxide/alginate beads for small-molecule drug delivery.

    Science.gov (United States)

    Chen, Kaihang; Ling, Yunzhi; Cao, Cong; Li, Xiaoyun; Chen, Xiao; Wang, Xiaoying

    2016-12-01

    This work reported chitosan derivatives (CSD)/reduced graphene oxide (rGO) blending with alginate to prepare hydrogel beads for small-molecule drug delivery for the first time. At the beginning, graphene oxide (GO) was successfully reduced using diverse CSD as reducing and stabilizing agents via facile heating. Then the obtained CSD/rGO was blended with alginate and crosslinked into hydrogel beads in CaCl2 solution. Finally, the beads were systematically evaluated as novel vehicles for pH-responsive small-molecule drug delivery. The optimal CSD/rGO/alginate beads showed a high drug-loading efficiency of 82.8% on small-molecule fluorescein sodium (FL), outstanding sustainable release of 71.6% upon 150h at a physiological pH and quick-release of 82.4% drug content at 20h in an acidic medium. Additionally, the cytotoxicity assay result suggested that the CSD/rGO/alginate beads showed negligible cytotoxicity to hepatic stellate cell lines, opening up possibilities for safe and efficient drug delivery. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. 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.

  17. Elimination of reactive blue 4 from aqueous solutions using 3-aminopropyl triethoxysilane modified chitosan beads.

    Science.gov (United States)

    Vakili, Mohammadtaghi; Rafatullah, Mohd; Salamatinia, Babak; Ibrahim, Mahamad Hakimi; Abdullah, Ahmad Zuhairi

    2015-11-05

    The adsorption behavior of chitosan (CS) beads modified with 3-aminopropyl triethoxysilane (APTES) for the removal of reactive blue 4 (RB4) in batch studies has been investigated. The effects of modification conditions, such as the APTES concentration, temperature and reaction time on RB4 removal, were studied. The adsorbent prepared at a concentration of 2 wt% APTES for 8h at 50 °C was the most effective one for RB4 adsorption. The adsorption capacity of modified CS beads (433.77 mg/g) was 1.37 times higher than that of unmodified CS beads (317.23 mg/g). The isotherm data are adequately described by a Freundlich model, and the kinetic study revealed that the pseudo-second-order rate model was in better agreement with the experimental data. The negative values of the thermodynamic parameters, including ΔG° (-2.28 and -4.70 kJ/mol at 30 ± 2 °C), ΔH° (-172.18 and -43.82 kJ/mol) and ΔS° (-560.71 and -129.08 J/mol K) for CS beads and APTES modified beads, respectively, suggest that RB4 adsorption is a spontaneous and exothermic process. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Heat regeneration of hydroxyapatite/attapulgite composite beads for defluoridation of drinking water.

    Science.gov (United States)

    Feng, Li; Xu, Weihua; Liu, Tengfei; Liu, Jason

    2012-06-30

    Regeneration is one of the key factors in evaluating an adsorbent. A novel heat regeneration method for hydroxyapatite/attapulgite (HAP/ATT) composite beads was studied. The investigation included heat regeneration temperature, regeneration time, and regeneration effects. A possible mechanism for the heat regeneration is described that explains the results of XPS, and SEM with EDAX. Exhausted HAP/ATT composite beads can be regenerated for more than 10 cycles using boiling water or steam. The total capacity increases by 10 times compared to a single defluoridation cycle. The regeneration process involves F(-) ions adsorbed on the surface of the beads to move quickly into the bulk of the HAP through the effect of heating this composite material. The surface active sites are thus re-exposed and the beads recover their fluoride sequestration properties. HAP/ATT composite beads were successfully used for the removal of fluoride from field water taken from a nearby village where fluoride contamination is endemic. Defluoridation and regeneration cycles performed in the same container provide a high efficient and simple operation. No chemical agents are used and no waste products are produced during the heat regeneration process, so this is a nearly zero emission process. This method can easily be up-scaled to a large throughput application. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Translocation of latex beads after laser ablation of the avian neural crest.

    Science.gov (United States)

    Coulombe, J N; Bronner-Fraser, M

    1984-11-01

    Previous studies from this laboratory (M.E. Bronner-Fraser, 1982, Dev. Biol. 91, 50-63) have demonstrated that latex beads translocate ventrally after injection into avian embryos during the phase of neural crest migration, to settle in the vicinity of neural-crest-derived structures. In order to examine the role of host neural crest cells in the ventral translocation of implanted beads, latex beads have been injected into regions of embryos from which the neural crest cells have been ablated using a laser microbeam. Prior to their migratory phase, neural crest cells reside in the dorsal portion of the neural tube. Laser irradiation of the dorsal neural tube was used to reproducibly achieve either partial or complete ablation of neural crest cells from the irradiated regions. The effectiveness of the ablation was assessed by the degree of reduction in dorsal root ganglia, a neural crest derivative. Because of the rapidity and precision of this technique, it was possible to selectively remove neural crest cells without significantly altering other embryonic structures. The results indicate that, after injection of latex beads into the somites of embryos whose neural crest cells were removed by laser irradiation, the beads translocate ventrally in the absence of the endogenous neural crest.

  20. 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.

  1. Influence of process parameters on the formability of bead stamping part using advanced models

    Science.gov (United States)

    Cha, W.; Müller, S.; Bursac, N.; Albers, A.; Volk, W.

    2017-09-01

    Beads are applied to deep drawn sheet metal parts to increase its stiffness. In order to form the bead, a two-stage manufacturing process including at least deep drawing and beading is performed. Thus, reductions of sheet metal thickness and consequently weight reduction can be effectively reached by numeric optimization. In order to apply the optimization algorithm to the production of non-virtual actual parts, the forming limits of the parts must be considered in both manufacturing steps. Bead formability is affected by process parameters such as blank holding force and lubrication. One way to investigate these influences is to use an accurate simulation model. In this study, the yield function named Yld2000-2D under non-associated flow rule is used to express anisotropic material behavior of blank and the Generalized Forming Limit Concept (GFLC) considering nonlinear strain paths is used to determine the formability. These models are validated by comparing the strain and bead forming limits measured in the Nakajima experiment. Then, the influences of mentioned process parameters are investigated by the validated model.

  2. Improving the controlled delivery formulations of caffeine in alginate hydrogel beads combined with pectin, carrageenan, chitosan and psyllium.

    Science.gov (United States)

    Belščak-Cvitanović, Ana; Komes, Draženka; Karlović, Sven; Djaković, Senka; Spoljarić, Igor; Mršić, Gordan; Ježek, Damir

    2015-01-15

    Alginate-based blends consisting of carrageenan, pectin, chitosan or psyllium husk powder were prepared for assessment of the best formulation aimed at encapsulation of caffeine. Alginate-pectin blend exhibited the lowest viscosity and provided the smallest beads. Alginate-psyllium husk blend was characterised with higher viscosity, yielding the largest bead size and the highest caffeine encapsulation efficiency (83.6%). The release kinetics of caffeine indicated that the porosity of alginate hydrogel was not reduced sufficiently to retard the diffusion of caffeine from the beads. Chitosan coated alginate beads provided the most retarded release of caffeine in water. Morphological characteristics of beads encapsulating caffeine were adversely affected by freeze drying. Bitterness intensity of caffeine-containing beads in water was the lowest for alginate-psyllium beads and chitosan coated alginate beads. Higher sodium alginate concentration (3%) for production of hydrogel beads in combination with psyllium or chitosan coating would present the most favourable carrier systems for immobilization of caffeine. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Preparation and in vitro characterization of gellan based floating beads of acetohydroxamic acid for eradication of H. pylori

    National Research Council Canada - National Science Library

    Rajinikanth, Parauvathanahalli Siddalingam; mishra, Brahmeshwar

    2007-01-01

    Gellan based floating beads of acetohydroxamic acid (AHA) were prepared by the ionotropic gellation method to achieve controlled and sustained drug release for treatment of Helicobacter pylori infection...

  4. Poly(methacrylic acid-co-methyl methacrylate) beads promote vascularization and wound repair in diabetic mice.

    Science.gov (United States)

    Martin, Daniel C; Semple, John L; Sefton, Michael V

    2010-05-01

    Topical application of beads made from poly(methacrylic acid-co-methyl methacrylate) (45 mol % methacrylic acid, MAA) increased the number of blood vessels and improved 1.5 x 1.5 cm full thickness wound closure in a diabetic mouse (db/db) model. Three groups were compared: MAA beads, control poly(methyl methacrylate) beads (PMMA), and no bead blanks. MAA bead treatment significantly increased percent wound closure at all timepoints (7, 14, and 21 days) with MAA bead-treated wounds almost closed at day 21 (91 +/- 5.4% MAA vs. 79 +/- 3.2% PMMA or 76 +/- 4.8% no beads; p < 0.05). This was consistent with the expected significant increase in vascularity in the MAA group at days 7 and 14. For example at day 14, MAA bead-treated wounds had a vascular density of 22.7 +/- 2.6 vessels/hpf compared with 17.0 +/- 2.0 vessels/hpf in the PMMA bead group (p < 0.05). Epithelial gap and migration measurements suggested that the increased vascularity leads to enhanced epithelial cell migration as a principal means of wound closure. Although studies are underway to elucidate the mechanism of this angiogenic response, the results presented here support the notion that such materials, perhaps in other forms, may be useful in wound care or in other situations where vascularity is to be enhanced without the use of exogenous growth factors. Copyright 2009 Wiley Periodicals, Inc.

  5. Fire-safe polymers and polymer composites

    Science.gov (United States)

    Zhang, Huiqing

    The intrinsic relationships between polymer structure, composition and fire behavior have been explored to develop new fire-safe polymeric materials. Different experimental techniques, especially three milligram-scale methods---pyrolysis-combustion flow calorimetry (PCFC), simultaneous thermal analysis (STA) and pyrolysis GC/MS---have been combined to fully characterize the thermal decomposition and flammability of polymers and polymer composites. Thermal stability, mass loss rate, char yield and properties of decomposition volatiles were found to be the most important parameters in determining polymer flammability. Most polymers decompose by either an unzipping or a random chain scission mechanism with an endothermic decomposition of 100--900 J/g. Aromatic or heteroaromatic rings, conjugated double or triple bonds and heteroatoms such as halogens, N, O, S, P and Si are the basic structural units for fire-resistant polymers. The flammability of polymers can also be successfully estimated by combining pyrolysis GC/MS results or chemical structures with TGA results. The thermal decomposition and flammability of two groups of inherently fire-resistant polymers---poly(hydroxyamide) (PHA) and its derivatives, and bisphenol C (BPC II) polyarylates---have been systematically studied. PHA and most of its derivatives have extremely low heat release rates and very high char yields upon combustion. PHA and its halogen derivatives can completely cyclize into quasi-polybenzoxazole (PBO) structures at low temperatures. However, the methoxy and phosphate derivatives show a very different behavior during decomposition and combustion. Molecular modeling shows that the formation of an enol intermediate is the rate-determining step in the thermal cyclization of PHA. BPC II-polyarylate is another extremely flame-resistant polymer. It can be used as an efficient flame-retardant agent in copolymers and blends. From PCFC results, the total heat of combustion of these copolymers or blends

  6. Electroluminescence of Multicomponent Conjugated Polymers. 1. Roles of Polymer/Polymer Interfaces in Emission Enhancement and Voltage-Tunable Multicolor Emission in Semiconducting Polymer/Polymer Heterojunctions

    National Research Council Canada - National Science Library

    Zhang, Xuejun, Ph.D

    1999-01-01

    Effects of the electronic structure of polymer/polymer interfaces on the electroluminescence efficiency and tunable multicolor emission of polymer heterojunction light-emitting diodes were explored...

  7. Biostable glucose permeable polymer

    DEFF Research Database (Denmark)

    2017-01-01

    A new biostable glucose permeable polymer has been developed which is useful, for example, in implantable glucose sensors. This biostable glucose permeable polymer has a number of advantageous characteristics and, for example, does not undergo hydrolytic cleavage and degradation, thereby providing...... a composition that facilitates long term sensor stability in vivo. The versatile characteristics of this polymer allow it to be used in a variety of contexts, for example to form the body of an implantable glucose sensor. The invention includes the polymer composition, sensor systems formed from this polymer...

  8. Nanoporous polymer electrolyte

    Science.gov (United States)

    Elliott, Brian [Wheat Ridge, CO; Nguyen, Vinh [Wheat Ridge, CO

    2012-04-24

    A nanoporous polymer electrolyte and methods for making the polymer electrolyte are disclosed. The polymer electrolyte comprises a crosslinked self-assembly of a polymerizable salt surfactant, wherein the crosslinked self-assembly includes nanopores and wherein the crosslinked self-assembly has a conductivity of at least 1.0.times.10.sup.-6 S/cm at 25.degree. C. The method of making a polymer electrolyte comprises providing a polymerizable salt surfactant. The method further comprises crosslinking the polymerizable salt surfactant to form a nanoporous polymer electrolyte.

  9. Polymer friction Molecular Dynamics

    DEFF Research Database (Denmark)

    Sivebæk, Ion Marius; Samoilov, Vladimir N.; Persson, Bo N. J.

    We present molecular dynamics friction calculations for confined hydrocarbon solids with molecular lengths from 20 to 1400 carbon atoms. Two cases are considered: a) polymer sliding against a hard substrate, and b) polymer sliding on polymer. In the first setup the shear stresses are relatively...... independent of molecular length. For polymer sliding on polymer the friction is significantly larger, and dependent on the molecular chain length. In both cases, the shear stresses are proportional to the squeezing pressure and finite at zero load, indicating an adhesional contribution to the friction force....

  10. In situ measurement of ferric iron in lunar glass beads using Fe-XAS

    Energy Technology Data Exchange (ETDEWEB)

    McCanta, Molly C.; Dyar, M. Darby; Rutherford, Malcolm J.; Lanzirotti, Antonio; Sutton, Stephen R.; Thomson, Bradley J.

    2017-03-01

    Through use of a new X-ray Absorption Spectroscopy (XAS) calibration for Fe3+ analysis in silicate glasses, the first direct measurements of ferric iron in natural lunar picritic glasses are presented. Lunar glass beads from the Apollo sample collection contain up to 60.0% Fe3+. No correlation with melt chemical properties, such as Mg# or weight % TiO2, or physical properties, such as bead diameter, was observed. Fe3+/ΣFe is negatively correlated with NBO/T. These elevated Fe3+/ΣFe values reflect eruption and post-eruption oxidation due to magmatic degassing of H or OH. Glass beads observed to be zoned to lower Fe3+/ΣFe rims may represent a subsequent reduction in the lunar vacuum prior to cooling through the glass transition temperature

  11. Magnetic bead micromixer: Influence of magnetic element geometry and field amplitude

    DEFF Research Database (Denmark)

    Lund-Olesen, Torsten; Buus, Bjarke B.; Howalt, Jakob

    2008-01-01

    A scheme for the silicon microfabrication of lab-on-a-chip systems with mixing based on dynamic plugs of magnetic beads is presented. The systems consist of a microfluidic channel integrated with a number of soft magnetic elements by the sides of the channel. The elements are magnetized...... by a homogeneous external ac magnetic field. The systems are scalable with respect to the number of magnetic bead plugs and number of parallel channels, and thus they have high potential for use in biological separation using functionalized magnetic beads. The mixing efficiency is characterized for two different...... geometries of the soft magnetic structures and found to be highly sensitive to the geometry and position of the structures....

  12. Facile synthesis of antibacterial chitosan/CuO bio-nanocomposite hydrogel beads.

    Science.gov (United States)

    Farhoudian, Sana; Yadollahi, Mehdi; Namazi, Hassan

    2016-01-01

    CuO nanoparticles were synthesized in situ during the formation of physically cross-linked chitosan hydrogel beads using sodium tripolyphosphate as the cross-linker. The aim of the study was to investigate whether these nanocomposite beads have the potential to be used in drug delivery applications. The formation of CuO nanoparticles (CuONPs) in the hydrogels was confirmed by X-ray diffraction and scanning electron microscopy studies. SEM micrographs revealed the formation of CuONPs with size range of 10-25 nm within the hydrogel matrix. Furthermore, the antibacterial and swelling properties of the beads were studied. The prepared nanocomposite hydrogels showed a pH sensitive swelling behavior. The CuO nanocomposite hydrogels have rather higher swelling in different aqueous solutions in comparison with neat hydrogel. The nanocomposite hydrogels demonstrated good antibacterial effects against Escherichia coli and Staphylococcus aureus bacteria. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Preparation of bismuth titanate/calcium alginate composite bead and its photocatalytic degradation of dye pollutants

    Science.gov (United States)

    Gan, Huihui; Dong, Nanyang; Lu, Linxiao; Fu, Yan; Zhang, Huining; Qian, Yongxin; Zhang, Kefeng; Jin, Huixia

    2017-08-01

    In this study, the bismuth titanate/calcium alginate composite bead was synthesized by immobilizing bismuth titanate Bi4Ti3O12 particles into 1.5% sodium alginate (SA) matrix. The Bi4Ti3O12 particles were characterized by X-ray diffraction (XRD). The photocatalytic activity for the degradation of dye Rhodamine B in solution by as-prepared bismuth titanate/calcium alginate composite bead was investigated. The as-prepared composite beads CA/BTO-700 exhibited best photocatalytic efficiency for the degradation of RhB compared with CA/BTO-800 and CA/BTO-900 under simulated solar light. After 4 cycles in photocatalytic degradation of RhB, the degradation rate of the CA/BTO-700 nearly remained unchanged.

  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. 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...

  16. In situ measurement of ferric iron in lunar glass beads using Fe-XAS

    Energy Technology Data Exchange (ETDEWEB)

    McCanta, Molly C.; Dyar, M. Darby; Rutherford, Malcolm J.; Lanzirotti, Antonio; Sutton, Stephen R.; Thomson, Bradley J.

    2017-03-01

    Through use of a new X-ray Absorption Spectroscopy (XAS) calibration for Fe3+ analysis in silicate glasses, the first direct measurements of ferric iron in natural lunar picritic glasses are presented. Lunar glass beads from the Apollo sample collection contain up to 60.0% Fe3+. No correlation with melt chemical properties, such as Mg# or weight % TiO2, or physical properties, such as bead diameter, was observed. Fe3+/ΣFe is negatively correlated with NBO/T. These elevated Fe3+/ΣFe values reflect eruption and post-eruption oxidation due to magmatic degassing of H or OH. Glass beads observed to be zoned to lower Fe3+/ΣFe rims may represent a subsequent reduction in the lunar vacuum prior to cooling through the glass transition temperature.

  17. Online measurement of bead geometry in GMAW-based additive manufacturing using passive vision

    Science.gov (United States)

    Xiong, Jun; Zhang, Guangjun

    2013-11-01

    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.

  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. Encapsulation of insulin in chitosan-coated alginate beads: oral therapeutic peptide delivery.

    Science.gov (United States)

    Onal, Seçil; Zihnioğlu, Figen

    2002-05-01

    Insulin was encapsulated in calcium alginate beads coated with chitosan. Its release from alginate-chitosan and alginate-chitosan-glutaraldehyde beads was studied in artificial gastric (pH 1.2) and intestinal (pH 7.5) fluids. By comparing the release amounts, the ionic interaction between alginate-chitosan matrix with the medium pH's, intestinal fluid was found to be the better. The degradation of released insulin was also searched, even after 6 h incubation, the beads remained stable and the undegraded insulin seemed to be sufficient for the physiological conditions. Consequently, it can be said that the system can be offered for oral delivery of the therapeutic peptide drug insulin.

  20. Advanced polymers in medicine

    CERN Document Server

    Puoci, Francesco

    2014-01-01

    The book provides an up-to-date overview of the diverse medical applications of advanced polymers. The book opens by presenting important background information on polymer chemistry and physicochemical characterization of polymers. This serves as essential scientific support for the subsequent chapters, each of which is devoted to the applications of polymers in a particular medical specialty. The coverage is broad, encompassing orthopedics, ophthalmology, tissue engineering, surgery, dentistry, oncology, drug delivery, nephrology, wound dressing and healing, and cardiology. The development of polymers that enhance the biocompatibility of blood-contacting medical devices and the incorporation of polymers within biosensors are also addressed. This book is an excellent guide to the recent advances in polymeric biomaterials and bridges the gap between the research literature and standard textbooks on the applications of polymers in medicine.

  1. Comparison of the kinetic friction of planar neutral and polyelectrolyte polymer brushes using molecular dynamics simulations.

    Science.gov (United States)

    Ou, Yangpeng; Sokoloff, Jeffrey B; Stevens, Mark J

    2012-01-01

    We have simulated the relative shear motion of both neutral and polyelectrolyte end-grafted polymer brushes using molecular dynamics. The flexible neutral polymer brush is treated as a bead-spring model, and the polyelectrolyte brush is treated the same way except that each bead is charged and there are counterions present to neutralize the charge. We investigated the friction coefficient, monomer density, and brush penetration for both polyelectrolyte and neutral brushes with both equal grafting density and equal normal force under good solvent conditions. We found that polyelectrolyte brushes had a smaller friction coefficient and monomer penetration than neutral polymer brushes with the identical grafting density and chain length, and the polyelectrolyte brushes supported a much higher normal load than the neutral brushes for the same degree of compression. Charged and neutral brushes with their grafting densities chosen so that they support the same load exhibited approximately the same degree of interpenetration, but the polyelectrolyte brush exhibited a significantly lower friction coefficient. We present evidence that the reason for this is that the extra normal force contribution provided by the counterion osmotic pressure that exists for polyelectrolyte brushes permits them to support the same load as an identical neutral polymer brush of higher grafting density. Because of the resulting lower monomer density for the charged brushes, fewer monomer collisions take place per unit time, resulting in a lower friction coefficient. © 2012 American Physical Society

  2. Beads task vs. box task: The specificity of the jumping to conclusions bias.

    Science.gov (United States)

    Balzan, Ryan P; Ephraums, Rachel; Delfabbro, Paul; Andreou, Christina

    2017-09-01

    Previous research involving the probabilistic reasoning 'beads task' has consistently demonstrated a jumping-to-conclusions (JTC) bias, where individuals with delusions make decisions based on limited evidence. However, recent studies have suggested that miscomprehension may be confounding the beads task. The current study aimed to test the conventional beads task against a conceptually simpler probabilistic reasoning "box task" METHODS: One hundred non-clinical participants completed both the beads task and the box task, and the Peters et al. Delusions Inventory (PDI) to assess for delusion-proneness. The number of 'draws to decision' was assessed for both tasks. Additionally, the total amount of on-screen evidence was manipulated for the box task, and two new box task measures were assessed (i.e., 'proportion of evidence requested' and 'deviation from optimal solution'). Despite being conceptually similar, the two tasks did not correlate, and participants requested significantly less information on the beads task relative to the box task. High-delusion-prone participants did not demonstrate hastier decisions on either task; in fact, for box task, this group was observed to be significantly more conservative than low-delusion-prone group. Neither task was incentivized; results need replication with a clinical sample. Participants, and particularly those identified as high-delusion-prone, displayed a more conservative style of responding on the novel box task, relative to the beads task. The two tasks, whilst conceptually similar, appear to be tapping different cognitive processes. The implications of these results are discussed in relation to the JTC bias and the theoretical mechanisms thought to underlie it. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Dentalium beads - shells of fosillised sea molluscs at the Vinča-Belo brdo site

    Directory of Open Access Journals (Sweden)

    Dimitrijević Vesna

    2010-01-01

    Full Text Available During excavation of the Vinča-Belo Brdo site a significant number of decorated items made from clay, stone, bone, and seashells or snail shells have been collected over the years. Amongst the decorated objects which could be classified as jewellery the majority are bracelets, pendants, and beads made from Spondylus and Glycymeris shells, as well as beads made from Dentalium shells. The appearance of these beads and the question of their origin have not yet been specifically considered within studies of prehistoric cultures in the central Balkans. Furthermore, they have rarely been illustrated and mentioned in archaeological site inventories, which we presume has not been because of their poor representation, but rather because of their being unfamiliar. The aim of this work is therefore to: a systematize data about Dentalium beads from all phases of excavation of the Belo Brdo site in Vinča; b to show the importance of this kind of jewellery in the study of resources around the Vinča settlement; and c to indicate the wider chronological perspective and the significance of studying Dentalium beads within the prehistory of the central Balkans. Dentalium is a carnivorous Scaphopoda sea mollusc, uncommon and insufficiently studied. Representatives of this class of Scaphopoda have been found on Serbian territory in the Badenian sediments, deposited fifteen million years ago. Badenian sediments were discovered around Loznica, Belgrade, Aranđelovac, Golubac, Zaječar, and Negotin. The region of Belgrade and the surrounding area had been covered by a warm, shallow sea of normal salination. On the territory of Belgrade, offsprings of the Badenian sediments, rich in fossils, have been discovered in the city centre (Tašmajdan, Kalemegdan, as well as in many surrounding places (Rakovica, Kaluđerica, Leštani, and Jajinci (fig. 2. Scaphopod shells found at the Vinča-Belo Brdo archaeological site are usually transversally broken. Judging by the basic

  4. Performance of dye-affinity beads for aluminium removal in magnetically stabilized fluidized bed

    Science.gov (United States)

    Yavuz, Handan; Say, Ridvan; Andaç, Müge; Bayraktar, Necmi; Denizli, Adil

    2004-01-01

    Background Aluminum has recently been recognized as a causative agent in dialysis encephalopathy, osteodystrophy, and microcytic anemia occurring in patients with chronic renal failure who undergo long-term hemodialysis. Only a small amount of Al(III) in dialysis solutions may give rise to these disorders. Methods Magnetic poly(2-hydroxyethyl methacrylate) (mPHEMA) beads in the size range of 80–120 μm were produced by free radical co-polymerization of HEMA and ethylene dimethacrylate (EDMA) in the presence of magnetite particles (Fe3O4). Then, metal complexing ligand alizarin yellow was covalently attached onto mPHEMA beads. Alizarin yellow loading was 208 μmol/g. These beads were used for the removal of Al(III) ions from tap and dialysis water in a magnetically stabilized fluidized bed. Results Al(III) adsorption capacity of the beads decreased with an increase in the flow-rate. The maximum Al(III) adsorption was observed at pH 5.0. Comparison of batch and magnetically stabilized fluidized bed (MSFB) maximum capacities determined using Langmuir isotherms showed that dynamic capacity (17.5 mg/g) was somewhat higher than the batch capacity (11.8 mg/g). The dissociation constants for Al(III) were determined using the Langmuir isotherm equation to be 27.3 mM (MSFB) and 6.7 mM (batch system), indicating medium affinity, which was typical for pseudospecific affinity ligands. Al(III) ions could be repeatedly adsorbed and desorbed with these beads without noticeable loss in their Al(III) adsorption capacity. Conclusions Adsorption of Al(III) demonstrate the affinity of magnetic dye-affinity beads. The MSFB experiments allowed us to conclude that this inexpensive sorbent system may be an important alternative to the existing adsorbents in the removal of aluminium. PMID:15329149

  5. Identification and correction of previously unreported spatial phenomena using raw Illumina BeadArray data

    Directory of Open Access Journals (Sweden)

    Tavaré Simon

    2010-04-01

    Full Text Available Abstract Background A key stage for all microarray analyses is the extraction of feature-intensities from an image. If this step goes wrong, then subsequent preprocessing and processing stages will stand little chance of rectifying the matter. Illumina employ random construction of their BeadArrays, making feature-intensity extraction even more important for the Illumina platform than for other technologies. In this paper we show that using raw Illumina data it is possible to identify, control, and perhaps correct for a range of spatial-related phenomena that affect feature-intensity extraction. Results We note that feature intensities can be unnaturally high when in the proximity of a number of phenomena relating either to the images themselves or to the layout of the beads on an array. Additionally we note that beads neighbour beads of the same type more often than one might expect, which may cause concern in some models of hybridization. We highlight issues in the identification of a bead's location, and in particular how this both affects and is affected by its intensity. Finally we show that beads can be wrongly identified in the image on either a local or array-wide scale, with obvious implications for data quality. Conclusions The image processing issues identified will often pass unnoticed by an analysis of the standard data returned from an experiment. We detail some simple diagnostics that can be implemented to identify problems of this nature, and outline approaches to correcting for such problems. These approaches require access to the raw data from the arrays, not just the summarized data usually returned, making the acquisition of such raw data highly desirable.

  6. Structure and transport properties of polymer grafted nanoparticles

    KAUST Repository

    Goyal, Sushmit

    2011-01-01

    We perform molecular dynamics simulations on a bead-spring model of pure polymer grafted nanoparticles (PGNs) and of a blend of PGNs with a polymer melt to investigate the correlation between PGN design parameters (such as particle core concentration, polymer grafting density, and polymer length) and properties, such as microstructure, particle mobility, and viscous response. Constant strain-rate simulations were carried out to calculate viscosities and a constant-stress ensemble was used to calculate yield stresses. The PGN systems are found to have less structural order, lower viscosity, and faster diffusivity with increasing length of the grafted chains for a given core concentration or grafting density. Decreasing grafting density causes depletion effects associated with the chains leading to close contacts between some particle cores. All systems were found to shear thin, with the pure PGN systems shear thinning more than the blend; also, the pure systems exhibited a clear yielding behavior that was absent in the blend. Regarding the mechanism of shear thinning at the high shear rates examined, it was found that the shear-induced decrease of Brownian stresses and increase in chain alignment, both correlate with the reduction of viscosity in the system with the latter being more dominant. A coupling between Brownian stresses and chain alignment was also observed wherein the non-equilibrium particle distribution itself promotes chain alignment in the direction of shear. © 2011 American Institute of Physics.

  7. Theoretical study of in-plane response of magnetic field sensor to magnetic beads magnetized by the sensor self-field

    DEFF Research Database (Denmark)

    Hansen, Troels Borum Grave; Damsgaard, Christian Danvad; Dalslet, Bjarke Thomas

    2010-01-01

    We present a theoretical study of the spatially averaged in-plane magnetic field on square and rectangular magnetic field sensors from a single magnetic bead, a monolayer of magnetic beads, and a half-space filled with magnetic beads being magnetized by the magnetic self-field due to the applied...... and analytical approximations are derived for the sensor response to beads as function of the bead distribution, the bias current, the geometry and size of the sensor, and the bead characteristics. Consequences for the sensor design are exemplified and it is described how the contribution from the self...

  8. Shedding light onto topological insulator beads: perspectives for optical tweezing application

    CERN Document Server

    Muller, Yuri G; Fonseca, Jakson M

    2016-01-01

    The interaction of electromagnetic radiation with a spheric-type three-dimensional topological insulator (TI) bead is described within classical optics framework. By virtue of the topological magnetoelectric effect (TMEE) experienced by reflected and transmitted rays at the TI surface, there appears a net constant force on the spherical bead which is proportional to the fine structure constant times the incident radiation power. Such an uniform dynamics (constant acceleration) may be particularly useful for optical tweeezing techniques, for instance, to investigate a DNA strip or a membrane piece under stretching as well as to displace a tiny object by means of purely optical control.

  9. Automated Solid-Phase Subcloning Based on Beads Brought into Proximity by Magnetic Force

    DEFF Research Database (Denmark)

    Hudson, Elton P.; Nikoshkov, Andrej; Uhlén, Mathias

    2012-01-01

    and the gene are immobilized to separate paramagnetic beads and brought into proximity by magnetic force. Ligation events were directly evaluated using fluorescent-based microscopy and flow cytometry. The highest ligation efficiencies were obtained when gene- and vector-coated beads were brought into close...... contact by application of a magnet during the ligation step. An automated procedure was developed using a laboratory workstation to transfer genes into various expression vectors and more than 95% correct clones were obtained in a number of various applications. The method presented here is suitable...

  10. Coherent state mapping ring polymer molecular dynamics for non-adiabatic quantum propagations

    Science.gov (United States)

    Chowdhury, Sutirtha N.; Huo, Pengfei

    2017-12-01

    We introduce the coherent-state mapping ring polymer molecular dynamics (CS-RPMD), a new method that accurately describes electronic non-adiabatic dynamics with explicit nuclear quantization. This new approach is derived by using coherent-state mapping representation for the electronic degrees of freedom (DOF) and the ring-polymer path-integral representation for the nuclear DOF. The CS-RPMD Hamiltonian does not contain any inter-bead coupling term in the state-dependent potential and correctly describes electronic Rabi oscillations. A classical equation of motion is used to sample initial configurations and propagate the trajectories from the CS-RPMD Hamiltonian. At the time equivalent to zero, the quantum Boltzmann distribution (QBD) is recovered by reweighting the sampled distribution with an additional phase factor. In a special limit that there is one bead for mapping variables and multiple beads for nuclei, CS-RPMD satisfies detailed balance and preserves an approximate QBD. Numerical tests of this method with a two-state model system show very good agreement with exact quantum results over a broad range of electronic couplings.

  11. Preparation of tri(ethylene glycol) grafted core-shell type polymer support for solid-phase peptide synthesis.

    Science.gov (United States)

    Kim, Jaehi; Kim, Seojung; Shin, Dong-Sik; Lee, Yoon-Sik

    2017-12-13

    A core-shell type polymer support for solid-phase peptide synthesis has been developed for high coupling efficiency of peptides and versatile applications such as on-bead bioassays. Although various kinds of polymer supports have been developed, they have their own drawbacks including poor accessibility of reagents and incompatibility in aqueous solution. In this paper, we prepared hydrophilic tri(ethylene glycol) (TEG) grafted core-shell type polymer supports (TEG SURE) for efficient solid-phase peptide synthesis and on-bead bioassays. TEG SURE was prepared by grafting TEG derivative on the surface of AM PS resin via biphasic diffusion control method and subsequent acetylation of amine groups which are located at the core region of AM PS resin. The performance of TEG SURE was evaluated by synthesizing several peptides. Three points can be highlighted: (1) easy control of loading level of TEG, (2) improved efficiency of peptide synthesis compared with the conventional resins, and (3) applicability of on-bead bioassays. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.

  12. A Universal Approach for Selective Trace Metal Determinations via Sequential Injection-Bead Injection-Lab-on-Valve (SI-BI-LOV) Using Renewable Reagent-loaded Hydrophobic Beads

    DEFF Research Database (Denmark)

    Long, Xiangbao; Miró, Manuel; Hansen, Elo Harald

    -Lab-on-Valve (SI-LOV) mode. The methodology uses poly(styrene-divinylbenzene) beads containing pendant octadecyl moieties (C18-PS/DVB), which are pre-impregnated with a selective organic metal chelating agent prior to the automatic manipulation of the beads in the microbore conduits of the LOV unit. By adapting......A new sample pretreatment approach is presented for selective and sensitive determination of trace metals via electrothermal atomic absorption spectrometry (ETAAS) based on the principle of bead injection (BI) with renewable reagent-loaded hydrophobic beads in a Sequential Injection...... in selecting the most favourable elution mode in order to attain the highest sensitivity. Cr(VI) is used as model analyte to demonstrate the potential of the SI-BI-LOV scheme, in which 1,5-diphenylcarbazide (DPC) is pre-impregnated on the beads, the surface of which serves as the active microzone. It is shown...

  13. Affinity separation of immunoglobulin G subclasses on dye attached poly(hydroxypropyl methacrylate) beads.

    Science.gov (United States)

    Yavuz, Handan; Akgöl, Sinan; Say, Ridvan; Denizli, Adil

    2006-11-15

    Poly(hydroxypropyl methacrylate) [poly(HPMA)] gel beads with an average size of 150-200 micro m were prepared by suspension polymerization of hydroxypropyl methacrylate (HPMA). The poly(HPMA) gel beads were characterized by swelling studies, surface area measurements, scanning electron microscopy (SEM) and elemental analysis. Poly(HPMA) gel beads had a specific surface area of 88.6 m(2)/g. The dye Reactive Green HE 4BD was chemically attached to yield dye-poly(HPMA) gel beads at an average concentration of 44.3 micro mol dye/g bead with a swelling ratio of 75%. These dye attached gel beads were used in the separation of immunoglobulin-G (IgG) through adsorption-elution studies. The non-specific adsorption of IgG on the poly(HPMA) gel beads was 0.5 mg/g. The attachment of Reactive Green HE 4BD significantly increased the adsorption of IgG up to 71 mg/g. The Langmuir adsorption model was found to be applicable in interpretation of data pertaining to the adsorption studies of IgG with Reactive Green HE 4BD attached to the poly(HPMA) gel beads. The adsorption of IgG was found to be optimal at pH 7.0. The adsorption of IgG was observed to decrease by about 76% as the NaCl concentration was increased from 0.001 to 0.1 M. The IgG adsorption capacity of the dye attached poly(HPMA) gel beads was determined for a commercially available IgG solution to be 4.2 mg/g for IgG(1), 64.5 mg/g for IgG(2), 7.1 mg/g for IgG(3) and 10.8 mg/g for IgG(4). The Reactive Green HE 4BD attached poly(HPMA) gel beads have a significant adsorption capacity for IgG(2). The quantity of adsorbed IgG(2) is three times higher than the quantity of the other subclasses, IgG(1), IgG(3) and IgG(4). A similar adsorption behaviour was observed when the albumin free human plasma was used. The quantity of adsorbed IgG(2) is higher than the quantity of the other subclasses, IgG(1), IgG(3) and IgG(4). Adsorption capacities for albumin free human plasma were obtained as 6.4 mg/g for IgG(1), 67.8 mg/g for IgG(2

  14. Effect of polymer molecular weight on the production of drug nanoparticles.

    Science.gov (United States)

    Sepassi, S; Goodwin, D J; Drake, A F; Holland, S; Leonard, G; Martini, L; Lawrence, M J

    2007-10-01

    Stable, polymer-coated nanoparticles of two hydrophobic drugs, namely nabumetone and halofantrine, have been prepared by a wet-bead milling process performed in the presence of a stabilizing homopolymer, either hydroxypropylmethylcellulose (HPMC) or polyvinylpyrrolidone (PVP), of differing molecular weights and concentrations. Although nabumetone nanoparticles could only be produced when HPMC was used as stabilizing polymer, halofantrine nanoparticles could be prepared using either HPMC or PVP. Stable nanoparticles of nabumetone could be produced using a HPMC solution of viscosity average molecular weight, M(v), of 5 kg/mol over an approximate four fold polymer concentration range (0.63-2.5% w/w) when a drug loading of 20% w/w was used. Increasing the molecular weight of HPMC up to a limiting M(v) of 89 kg/mol did not result in the formation of nanoparticles at any of the polymer concentrations examined. The amount of polymer absorbed onto the nanoparticles was determined by measuring the depletion of polymer from solution based on either an ultra-violet (PVP) or optical rotatory dispersion (ORD) (HPMC) assay. The slightly lower concentration of HMPC found to be present on the surface of the halofantrine nanoparticles compared with the nabumetone nanoparticles suggested a differing affinity of the polymer for the surface of the two drugs. (c) 2007 Wiley-Liss, Inc.

  15. Structure and dynamical intra-molecular heterogeneity of star polymer melts above glass transition temperature

    Science.gov (United States)

    Chremos, Alexandros; Glynos, Emmanouil; Green, Peter F.

    2015-01-01

    Structural and dynamical properties of star melts have been investigated with molecular dynamics simulations of a bead-spring model. Star polymers are known to be heterogeneous, but a systematic simulation study of their properties in melt conditions near the glass transition temperature was lacking. To probe their properties, we have expanded from linear to star polymers the applicability of Dobkowski's chain-length dependence correlation function [Z. Dobkowski, Eur. Polym. J. 18, 563 (1982)]. The density and the isokinetic temperature, based on the canonical definition of the laboratory glass-transition, can be described well by the correlation function and a subtle behavior manifests as the architecture becomes more complex. For linear polymer chains and low functionality star polymers, we find that an increase of the arm length would result in an increase of the density and the isokinetic temperature, but high functionality star polymers have the opposite behavior. The effect between low and high functionalities is more pronounced for short arm lengths. Complementary results such as the specific volume and number of neighbors in contact provide further insights on the subtle relation between structure and dynamics. The findings would be valuable to polymer, colloidal, and nanocomposites fields for the design of materials in absence of solution with the desired properties.

  16. Brownian dynamics of a protein-polymer chain complex in a solid-state nanopore

    Science.gov (United States)

    Wells, Craig C.; Melnikov, Dmitriy V.; Gracheva, Maria E.

    2017-08-01

    We study the movement of a polymer attached to a large protein inside a nanopore in a thin silicon dioxide membrane submerged in an electrolyte solution. We use Brownian dynamics to describe the motion of a negatively charged polymer chain of varying lengths attached to a neutral protein modeled as a spherical bead with a radius larger than that of the nanopore, allowing the chain to thread the nanopore but preventing it from translocating. The motion of the protein-polymer complex within the pore is also compared to that of a freely translocating polymer. Our results show that the free polymer's standard deviations in the direction normal to the pore axis is greater than that of the protein-polymer complex. We find that restrictions imposed by the protein, bias, and neighboring chain segments aid in controlling the position of the chain in the pore. Understanding the behavior of the protein-polymer chain complex may lead to methods that improve molecule identification by increasing the resolution of ionic current measurements.

  17. Star-Branched Polymers (Star Polymers)

    KAUST Repository

    Hirao, Akira

    2015-09-01

    The synthesis of well-defined regular and asymmetric mixed arm (hereinafter miktoarm) star-branched polymers by the living anionic polymerization is reviewed in this chapter. In particular, much attention is being devoted to the synthetic development of miktoarm star polymers since 2000. At the present time, the almost all types of multiarmed and multicomponent miktoarm star polymers have become feasible by using recently developed iterative strategy. For example, the following well-defined stars have been successfully synthesized: 3-arm ABC, 4-arm ABCD, 5-arm ABCDE, 6-arm ABCDEF, 7-arm ABCDEFG, 6-arm ABC, 9-arm ABC, 12-arm ABC, 13-arm ABCD, 9-arm AB, 17-arm AB, 33-arm AB, 7-arm ABC, 15-arm ABCD, and 31-arm ABCDE miktoarm star polymers, most of which are quite new and difficult to synthesize by the end of the 1990s. Several new specialty functional star polymers composed of vinyl polymer segments and rigid rodlike poly(acetylene) arms, helical polypeptide, or helical poly(hexyl isocyanate) arms are introduced.

  18. The performance of polymer beads in water-based mud and its application in high-temperature well

    National Research Council Canada - National Science Library

    Mamat, Nur Suriani; Ismail, Issham; Hashim, Shahrir; Kamis, Azmi; Abdul Razak, Aizal Haziq

    2013-01-01

    The major concern in multilateral drilling is the torque and drag that arises as we drill deeper coupled with the escalation of bottomhole temperature, which can be overcome through the use of a lubricant...

  19. Chemistry and petrology of Fe-Ni beads from different types of cosmic spherules: Implication for precursors

    Digital Repository Service at National Institute of Oceanography (India)

    Rudraswami, N.G.; ShyamPrasad, M.; Babu, E.V.S.S.K.; VijayaKumar, T.

    Fe–Ni beads are observed to occur in all three (Stony, Glass, Iron) types of cosmic spherules collected from deep sea sediments of the Indian Ocean. Fe–Ni beads in cosmic spherules can provide insights for understanding metal segregation mechanisms...

  20. Chitosan-cinnamon beads enhance suppressive activity against Rhizoctonia solani and Meloidogyne incognita in vitro.

    Science.gov (United States)

    Seo, Dong-Jun; Nguyen, Dang-Minh-Chanh; Park, Ro-Dong; Jung, Woo-Jin

    2014-01-01

    A novel chitosan-cinnamon bead carrier was prepared in this study. Chitosan was mixed with cinnamon powder (CP) and cinnamon extract (CE) to obtain chitosan-cinnamon powder (CCP) beads and chitosan-cinnamon extracted (CCE) beads, respectively. The potential antifungal and nematicidal activities of CCP and CCE were investigated against Rhizoctonia solani and Meloidogyne incognita in vitro. Relative antifungal activity of the CCP (5% CP) bead-treated R. solani was 30.9 and 23.9% after 1 and 2 day incubations, respectively. Relative antifungal activity of the CCE (0.5% CE) bead-treated R. solani was 4.3, 3.0 and 4.2% after 1, 2 and 3 days of incubation. Inhibition of hatch by CCP beads with CP of 5% was 78.8%. Inhibition of hatch by CCE beads with CE of 0.5% was 82.0%. J2 mortality following the CCP (5% CP) and CCE (0.5% CE) bead treatments was 85.0 and 95.8%, respectively against M. incognita after 48 h incubations. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Microfabricated Renewable Beads-Trapping/Releasing Flow Cell for Rapid Antigen-Antibody Reaction in Chemiluminescent Immunoassay

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Zhifeng; Shao, Guocheng; Wang, Jun; Lu, Donglai; Wang, Wanjun; Lin, Yuehe

    2011-04-01

    A filter pillar-array microstructure was coupled with a pneumatic micro-valve to fabricate a reusable miniaturized beads-trapping/releasing flow cell, in which trapping and releasing beads can be conveniently realized by switching the micro-valve. This miniaturized device was suitable to construct automatic fluidic system for “renewable surface analysis”. The renewable surface strategy based on pneumatic micro-valve enabled capture of beads in beads chamber prior to each assay, and release of the used beads after the assay. Chemiluminescent competitive immunoassay of 3,5,6-trichloropyridinol (TCP) was performed as a model to demonstrate the application potential of this reusable miniaturized flow cell. The whole fluidic assay process including beads trapping, immuno-binding, beads washing, beads releasing and signal collection could be completed in 10 min. Immunoassay of TCP using this miniaturized device showed a linear range of 0.20-70 ng/mL with a limit of detection of 0.080 ng/mL. The device had been successfully used for detection of TCP spiked in rat serum with average recovery of 97%. This investigation provides a rapid, sensitive, reusable, low-cost and automatic miniaturized device for solid-phase biochemical analysis for various purposes.

  2. How can we reduce costs of solid-phase multiplex-bead assays used to determine anti-HLA antibodies?

    NARCIS (Netherlands)

    Kamburova, E.G.; Wisse, B.W.; Joosten, I.; Allebes, W.A.; Meer, A. van der; Hilbrands, L.B.; Baas, M.C.; Spierings, E.; Hack, C.E.; Reekum, F.E. van; Zuilen, A.D. van; Verhaar, M.; Bots, M.L.; Drop, A.C.; Plaisier, L.; Seelen, M.A.; Sanders, J.S.; Hepkema, B.G.; Lambeck, A.J.A.; Bungener, L.B.; Roozendaal, C.; Tilanus, M.G.; Vanderlocht, J.; Voorter, C.E.M.; Wieten, L.; Duijnhoven, E.M. van; Gelens, M.; Christiaans, M.H.; Ittersum, F.J. van; Nurmohamed, A.; Lardy, N.M.; Swelsen, W.; Pant, K.A. van der; Weerd, N.C. van der; Berge, I.J. Ten; Bemelman, F.J.; Hoitsma, A.; Boog, P.J. van der; Fijter, J.W. de; Betjes, M.G.; Heidt, S.; Roelen, D.L.; Claas, F.H.; Otten, H.G.

    2016-01-01

    Solid-phase multiplex-bead assays are widely used in transplantation to detect anti-human leukocyte antigen (HLA) antibodies. These assays enable high resolution detection of low levels of HLA antibodies. However, multiplex-bead assays are costly and yield variable measurements that limit the

  3. How can we reduce costs of solid-phase multiplex-bead assays used to determine anti-HLA antibodies?

    NARCIS (Netherlands)

    Kamburova, E. G.; Wisse, B. W.; Joosten, I.; Allebes, W. A.; van der Meer, A.; Hilbrands, L. B.; Baas, M. C.; Spierings, E.; Hack, C. E.; van Reekum, F. E.; van Zuilen, A. D.; Verhaar, M.; Bots, M. L.; Drop, A. C. A. D.; Plaisier, L.; Seelen, M. A. J.; Sanders, J. S. F.; Hepkema, B. G.; Lambeck, A. J.; Bungener, L. B.; Roozendaal, C.; Tilanus, M. G. J.; Vanderlocht, J.; Voorter, C. E.; Wieten, L.; van Duijnhoven, E. M.; Gelens, M.; Christiaans, M. H. L.; van Ittersum, F. J.; Nurmohamed, A.; Lardy, N. M.; Swelsen, W.; van der Pant, K. A.; van der Weerd, N. C.; ten Berge, I. J. M.; Bemelman, F. J.; Hoitsma, A.; van der Boog, P. J. M.; de Fijter, J. W.; Betjes, M. G. H.; Heidt, S.; Roelen, D. L.; Claas, F. H.; Otten, H. G.

    Solid-phase multiplex-bead assays are widely used in transplantation to detect anti-human leukocyte antigen (HLA) antibodies. These assays enable high resolution detection of low levels of HLA antibodies. However, multiplex-bead assays are costly and yield variable measurements that limit the

  4. Antibody-integrated and functionalized graphite-encapsulated magnetic beads, produced using ammonia gas plasma technology, for capturing Salmonella.

    Science.gov (United States)

    Sakudo, Akikazu; Chou, Han; Nagatsu, Masaaki

    2015-03-01

    Salmonella spp. is the single and most important causative agent of foodborne infections, especially involving foods such as eggs, milk and meat. To prevent infection, a reliable surveillance system is required that can quickly and sensitively detect Salmonella. Here, we describe the development of antibody-integrated magnetic beads that are functionalized by a novel strategy using ammonia gas plasma. Ammonia plasma, produced by a radio frequency (RF) power supply, was allowed to react with the surface of graphite-encapsulated magnetic beads, resulting in the introduction of amino groups. An anti-Salmonella antibody was then anchored by sulfide groups present on the protein surface to the amino groups of the magnetic beads via N-succinimidyl 3-(2-pyridyldithio) propionate (SPDP). The potential usefulness of these magnetic beads for capturing Salmonella was examined as follows. The beads were incubated with Salmonella in liquid medium and then separated from the supernatant by applying a magnetic field. After thorough washing, adsorption of Salmonella to the beads was confirmed by immunochromatography, polymerase chain reaction and a direct culture assay. Our findings indicate that the capture and concentration of Salmonella using the antibody-integrated magnetic beads was more efficient than commercial Dynabeads® anti-Salmonella, which are conventionally used for concentrating Salmonella from liquid cultures. We believe this novel bead technology will contribute to the enhanced detection of Salmonella. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Artificially Engineered Protein Polymers.

    Science.gov (United States)

    Yang, Yun Jung; Holmberg, Angela L; Olsen, Bradley D

    2017-06-07

    Modern polymer science increasingly requires precise control over macromolecular structure and properties for engineering advanced materials and biomedical systems. The application of biological processes to design and synthesize artificial protein polymers offers a means for furthering macromolecular tunability, enabling polymers with dispersities of ∼1.0 and monomer-level sequence control. Taking inspiration from materials evolved in nature, scientists have created modular building blocks with simplified monomer sequences that replicate the function of natural systems. The corresponding protein engineering toolbox has enabled the systematic development of complex functional polymeric materials across areas as diverse as adhesives, responsive polymers, and medical materials. This review discusses the natural proteins that have inspired the development of key building blocks for protein polymer engineering and the function of these elements in material design. The prospects and progress for scalable commercialization of protein polymers are reviewed, discussing both technology needs and opportunities.

  6. Freeze-thaw immobilization of liposomes in chromatographic gel beads: evaluation by confocal microscopy and effects of freezing rate.

    Science.gov (United States)

    Lundqvist, A; Ocklind, G; Haneskog, L; Lundahl, P

    1998-01-01

    Biological membranes immobilized in chromatographic gel beads constitute a multifunctional affinity matrix. Membrane protein-solute interactions and drug partitioning into the lipid bilayers can conveniently be studied. By the use of confocal laser-scanning microscopy (CLSM) the distribution of immobilized model membranes in the beads has been visualized for the first time. Freeze-thaw-immobilized liposomes in Superdex 200 gel beads were situated in a thick shell surrounding a liposome-free core. The amount of phospholipids immobilized by freeze-thawing was dependent on the temperature in the cooling bath and the type of test tube used. A bath temperature of -25 degrees C gave higher immobilization yield than freezing at -75 or -8 degrees C did. Freeze-thawing in the presence of liposomes did not affect the gel bead shape or the refractive index homogeneity of the agarose network of the beads, as shown by confocal microscopy.

  7. Organization of polymer chains onto long, single-wall carbon nano-tubes: effect of tube diameter and cooling method.

    Science.gov (United States)

    Kumar, Sunil; Pattanayek, Sudip K; Pereira, Gerald G

    2014-01-14

    We use molecular dynamics simulations to investigate the arrangement of polymer chains when absorbed onto a long, single-wall carbon nano-tube (SWCNT). We study the conformation and organization of the polymer chains on the SWCNT and their dependence on the tube's diameter and the rate of cooling. We use two types of cooling processes: direct quenching and gradual cooling. The radial density distribution function and bond orientational order parameter are used to characterize the polymer chain structure near the surface. In the direct cooling process, the beads of the polymer chain organize in lamella-like patterns on the surface of the SWCNT with the long axis of the lamella parallel to the axis of the SWCNT. In a stepwise, gradual cooling process, the polymer beads form a helical pattern on the surface of a relatively thick SWCNT, but form a lamella-like pattern on the surface of a very thin SWCNT. We develop a theoretical (free energy) model to explain this difference in pattern structures for the gradual cooling process and also provide a qualitative explanation for the pattern that forms from the direct cooling process.

  8. Thermally conductive polymers

    Science.gov (United States)

    Byrd, N. R.; Jenkins, R. K.; Lister, J. L. (Inventor)

    1971-01-01

    A thermally conductive polymer is provided having physical and chemical properties suited to use as a medium for potting electrical components. The polymer is prepared from hydroquinone, phenol, and formaldehyde, by conventional procedures employed for the preparation of phenol-formaldehyde resins. While the proportions of the monomers can be varied, a preferred polymer is formed from the monomers in a 1:1:2.4 molar or ratio of hydroquinone:phenol:formaldehyde.

  9. On-Chip Manipulation of Protein-Coated Magnetic Beads via Domain-Wall Conduits

    DEFF Research Database (Denmark)

    Donolato, Marco; Vavassori, Paolo; Gobbi, Marco

    2010-01-01

    Geometrically constrained magnetic domain walls (DWs) in magnetic nanowires can be manipulated at the nanometer scale. The inhomogeneous magnetic stray field generated by a DW can capture a magnetic nanoparticle in solution. On-chip nanomanipulation of individual magnetic beads coated with proteins...

  10. Microplate Agglutination Test for Canine Brucellosis Using Recombinant Antigen-Coated Beads.

    Science.gov (United States)

    Castillo, Yussaira; Tachibana, Masato; Kimura, Yui; Kim, Suk; Ichikawa, Yasuaki; Endo, Yasuyuki; Watanabe, Kenta; Shimizu, Takashi; Watarai, Masahisa

    2014-01-01

    Brucella canis, a facultative intracellular pathogen, is the causative agent of canine brucellosis. The diagnosis of canine brucellosis is based on bacteriological examination and serological methods, including agglutination and gel diffusion tests. In this study, four recombinant antigens, heat shock protein 60, rhizopine-binding protein, Cu-Zn superoxide dismutase, and hypothetical protein (Ag 4), were constructed. These antigens were coated on latex beads and their usefulness in the serological diagnosis of canine brucellosis was examined. All recombinant antigens showed specific reaction with sera from B. canis-infected dogs in Western blotting. In a microplate agglutination test, mixing sera from B. canis-infected dogs, but not sera from B. canis-free dogs, with single or multiple antigens-coated latex beads produced clear agglutination. Moreover, the antigen-coated latex beads did not show nonspecific agglutination in hemolyzed serum samples. A survey of canine serum samples conducted by the microplate agglutination test using single antigen-coated latex beads showed that this method would be useful in the serological diagnosis of canine brucellosis. Further investigations using more serum samples are required to confirm the usefulness of our method.

  11. A low-cost 2D fluorescence detection system for mm sized beads on-chip

    NARCIS (Netherlands)

    Segerink, Loes Irene; Koster, Maarten J.; Sprenkels, A.J.; van den Berg, Albert

    2012-01-01

    In this paper we describe a compact fluorescence detection system for on-chip analysis of beads, comprising a low-cost optical HD-DVD pickup. The complete system consists of a fluorescence detection unit, a control unit and a microfluidic chip containing microchannels and optical markers. With these

  12. Laminin-Alginate Beads as Preadipocyte Carriers to Enhance Adipogenesis In Vitro and In Vivo.

    Science.gov (United States)

    Hsueh, Yu-Sheng; Chen, Yo-Shen; Tai, Hao-Chih; Mestak, Ondrej; Chao, Sung-Chuan; Chen, Yen-Yu; Shih, Ying; Lin, Jung-Feng; Shieh, Ming-Jium; Lin, Feng-Huei

    2017-03-01

    The use of autologous fat grafting in breast reconstruction still requires optimization. Fat survival and calcification are the main issues that affect the outcomes of the procedure. In this study, a cell-based therapy utilizing laminin-alginate beads (LABs) as carriers was proposed to promote cell survival and adipogenesis by providing short-term physical support and facilitate nutrient diffusion of the implants. Laminin-modified alginate beads were fabricated by immobilizing laminin onto ring-opened alginate, used to encapsulate 3T3-L1 preadipocytes, and evaluated in vitro and in vivo. LABs as preadipocyte carriers showed better biocompatibility and stability than unmodified alginate beads. Preadipocytes in LABs had higher survival rate and enhanced adipogenesis than those in unmodified alginate beads. In vivo studies showed that LABs gradually degraded and the sites were replaced by newly formed fat tissues, and new blood vessels were also observed. 7T-MRI study mimicking clinical fat grafting showed that LABs carrying adipose stem cells improved the results of conventional fat grafts. Therefore, we believe that LABs represent promising cell carriers and can be potentially used for the reconstruction of breasts or other soft tissues in the future.

  13. Fabrication of large size alginate beads for three-dimensional cell-cluster culture

    Science.gov (United States)

    Zhang, Zhengtao; Ruan, Meilin; Liu, Hongni; Cao, Yiping; He, Rongxiang

    2017-08-01

    We fabricated large size alginate beads using a simple microfluidic device under a co-axial injection regime. This device was made by PDMS casting with a mold formed by small diameter metal and polytetrafluorothylene tubes. Droplets of 2% sodium alginate were generated in soybean oil through the device and then cross-linked in a 2% CaCl2 solution, which was mixed tween80 with at a concentration of 0.4 to 40% (w/v). Our results showed that the morphology of the produced alginate beads strongly depends on the tween80 concentration. With the increase of concentration of tween80, the shape of the alginate beads varied from semi-spherical to tailed-spherical, due to the decrease of interface tension between oil and cross-link solution. To access the biocompatibility of the approach, MCF-7 cells were cultured with the alginate beads, showing the formation of cancer cells clusters which might be useful for future studies.

  14. Encapsulation of lactase in Ca(II)-alginate beads: Effect of stabilizers and drying methods.

    Science.gov (United States)

    Traffano-Schiffo, Maria Victoria; Castro-Giraldez, Marta; Fito, Pedro J; Santagapita, Patricio R

    2017-10-01

    The purpose of the present work was to analyze the effect of trehalose, arabic and guar gums on the preservation of β-galactosidase activity in freeze-dried and vacuum dried Ca(II)-alginate beads. Freezing process was also studied as a first step of freeze-drying. Trehalose was critical for β-galactosidase conservation, and guar gum as a second excipient showed the highest conservation effect (close to 95%). Systems with Tg values ~40°C which were stables at ambient temperature were obtained, being trehalose the main responsible of the formation of an amorphous matrix. Vacuum dried beads showed smaller size (with Feret's diameter below 1.08±0.09mm), higher circularity (reaching 0.78±0.06) and large cracks in their surface than freeze-dried beads, which were more spongy and voluminous. Ice crystallization of the beads revealed that the crystallization of Ca(II)-alginate system follows the Avrami kinetics of nucleation and growth. Particularly, Ca(II)-alginate showed an Avrami index of 2.03±0.07, which means that crystal growing is bidimensional. Neither the addition of trehalose nor gums affected the dimension of the ice growing or its rate. These results open an opportunity in the development of new lactic products able to be consumed by lactose intolerance people. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Evaluating Length: The Use of Low-dose Biplanar Radiography (EOS) and Tantalum Bead Implantation.

    Science.gov (United States)

    Garner, Matthew R; Dow, Matthew; Bixby, Elise; Mintz, Doug N; Widmann, Roger F; Dodwell, Emily R

    2016-01-01

    Low-dose biplanar radiography (EOS) is an appealing imaging modality for use in children given its low radiation and ease of use. The goal of this study was to determine the accuracy and reliability of EOS compared with CT scanogram for measurement of leg length and to assess interrater and intrarater reliability of measured interbead distances for EOS and CT scanogram after insertion of tantalum beads into lamb femurs. Tantalum beads (0.8 mm) were inserted into the cortex on both the medial and lateral sides of 10 skeletally immature lamb femurs. CT scanogram and EOS imaging were obtained. Measurements of total length and distance between bead pairs were recorded on anteroposterior and lateral views by 2 orthopaedic surgeons on 2 separate occasions. Pearson correlations were performed for statistical comparisons. EOS measurements showed near-perfect correlation to those of CT scanogram (r>0.96, P0.98, P0.99, P0.98, P0.99, Ptantalum bead implantation may be an effective way to evaluate physeal growth following procedures such as epiphysiodesis and physeal bar resection. Level II—diagnostic

  16. Life, Death and Transformation: Education and Incompleteness in Hermann Hesse's "The Glass Bead Game"

    Science.gov (United States)

    Roberts, Peter

    2008-01-01

    At the end of the main part of Hermann Hesse's classic novel, "The Glass Bead Game," the central character, Joseph Knecht, dies suddenly. In this article, I consider the educational significance of Hesse's portrayal of Knecht's death. This pivotal moment in the book tells readers much about the process of educational transformation. I argue that…

  17. Pathogen detection in produce using applications of immunomagnetic beads and biosensors

    Science.gov (United States)

    The presence of pathogenic bacteria is of increasing public health concerns. Rapid and sensitive tests to detect pathogens are required to keep the safety of food supply. In this chapter we summarized our previous investigations where we applied immunomagnetic-bead (IMB) capture and various biosen...

  18. Rifabutin-loaded Floating Gellan Gum Beads: Effect of Calcium and ...

    African Journals Online (AJOL)

    Erah

    dissolution apparatus type II in 0.01M HCl (ph 2.0) as the dissolution medium. The shape, surface morphology and ... Keywords: Floating beads, Gellan gum, Incorporation efficiency, Rifabutin, Stomach-specific release. Received: 18 August 2010 ... induced by cations and is temperature- dependent. In aqueous solution, the ...

  19. "On-chip magnetic bead microarray using hydrodynamic focusing in a passive magnetic separator"

    DEFF Research Database (Denmark)

    Smistrup, Kristian; Kjeldsen, B.; Reimers, R.L.

    2005-01-01

    Implementing DNA and protein microarrays into lab-on-a-chip systems can be problematic since these are sensitive to heat and strong chemicals. Here, we describe the functionalization of a microchannel with two types of magnetic beads using hydrodynamic focusing combined with a passive magnetic...

  20. Lipopolysaccharide-induced multinuclear cells: Increased internalization of polystyrene beads and possible signals for cell fusion

    Energy Technology Data Exchange (ETDEWEB)

    Nakanishi-Matsui, Mayumi, E-mail: nakanim@iwate-med.ac.jp; Yano, Shio; Futai, Masamitsu

    2013-11-01

    Highlights: •LPS induces multinuclear cells from murine macrophage-derived RAW264.7 cells. •Large beads are internalized by cells actively fusing to become multinuclear. •The multinuclear cell formation is inhibited by anti-inflammatory cytokine, IL10. •Signal transduction for cell fusion is different from that for inflammation. -- Abstract: A murine macrophage-derived line, RAW264.7, becomes multinuclear on stimulation with lipopolysaccharide (LPS), an outer membrane component of Gram-negative bacteria. These multinuclear cells internalized more polystyrene beads than mononuclear cells or osteoclasts (Nakanishi-Matsui, M., Yano, S., Matsumoto, N., and Futai, M., 2012). In this study, we analyzed the time courses of cell fusion in the presence of large beads. They were internalized into cells actively fusing to become multinuclear. However, the multinuclear cells once formed showed only low phagocytosis activity. These results suggest that formation of the multinuclear cells and bead internalization took place simultaneously. The formation of multinuclear cells was blocked by inhibitors for phosphoinositide 3-kinase, phospholipase C, calcineurin, and c-Jun N-terminal kinase. In addition, interleukin 6 and 10 also exhibited inhibitory effects. These signaling molecules and cytokines may play a crucial role in the LPS-induced multinuclear cell formation.

  1. Removal of textile dye, direct red 23, with glutaraldehyde cross-linked magnetic chitosan beads.

    Science.gov (United States)

    Sanlier, Senay Hamarat; Ak, Güliz; Yilmaz, Habibe; Ozbakir, Gizem; Cagliyan, Oguzhan

    2013-01-01

    One of the most important classes of pollutants is dyes, and today there are more than 100,000 commercial dyes. Conventional treatment processes are very expensive, so it is essential to develop low-cost sorbent materials with high adsorption capacities. The aim of this study is to prepare magnetic microsized adsorbents that have high adsorption capacity for removal of direct red 23. Through this objective, glutaraldehyde cross-linked magnetic chitosan beads were formed in order to remove the textile dye direct red 23. Barium ferrite was used to give a magnetic property so that the beads could easily be separated from the water after treatment. The effects of barium ferrite, pH, incubation time, dye concentration, and glutaraldehyde amounts were investigated. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms. The adsorption capacity had a very large value: 1250 mg/g at pH 4.0, at room temperature. Compared with activated carbon, magnetic cross-linked chitosan exhibits excellent performance in the adsorption of anionic dyes and the magnetic properties of beads enable us to remove the beads from the water after treatment. Pseudo-second-order and intraparticle diffusion kinetic models were applied.

  2. Alginate-based polysaccharide beads for cationic contaminant sorption from water

    Science.gov (United States)

    Mei Li; Thomas Elder; Gisela Buschle-Diller

    2016-01-01

    Massive amounts of agricultural and industrial water worldwide are polluted by different types of contaminants that harm the environment and impact human health. Removing the contaminants from effluents by adsorbent materials made from abundant, inexpensive polysaccharides is a feasible approach to deal with this problem. In this research, alginate beads combined with...

  3. Identification of c-di-AMP-Binding Proteins Using Magnetic Beads.

    Science.gov (United States)

    Kampf, Jan; Gundlach, Jan; Herzberg, Christina; Treffon, Katrin; Stülke, Jörg

    2017-01-01

    To identify cytosolic proteins that bind to cyclic di-AMP, a biotinylated analog of the nucleotide is used for protein pull-down experiments. In this approach, biotinylated c-di-AMP is coupled to Streptactin-covered beads. After protein separation using standard SDS-PAGE, the protein(s) of interest are identified by mass spectrometric analyses.

  4. A Multiplex PCR-coupled Liquid Bead Array for the Simultaneous Detection of Four Biothreat Agents

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, W J; Erler, A M; Nasarabadi, S L; Skowronski, E W; McCready, P M

    2004-02-04

    We have developed a 10-plexed PCR assay coupled to a 12-plexed liquid bead array to rapidly screen environmental samples for B. anthracis, Y. pestis, F. tularensis, and B. melitensis. Highly validated species -specific primer sets were used to simultaneously amplify multiple diagnostic regions unique to each individual pathogen. Resolution of the mix of amplified products was achieved by PCR product hybridization to corresponding probe sequences, attached to unique sets of fluorescent beads. The hybridized beads were processed through a flow cytometer, which detected presence and quantity of each PCR product. The assay was optimized to allow for maximum sensitivity in a multiplexed format. A high- throughput demonstration was performed where 384 simulated environmental samples were spiked with different amounts of B. thuringensis spores and pathogen DNA. The samples were robotically processed to extract DNA and arrayed for multiplexed PCR-liquid bead detection. The assay correctly identified the presence or absence of each pathogen and collected over 3,000 individual data points within a single 8-hour shift for approximately $1.20 per sample in a 10-plexed assay.

  5. Measurement of the diffusion coefficients of fluorescence beads and quantum dots by using fluorescence correlation spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Han, Yesul; Lee, Jaeran; Lee, Yumi; Kim, Sokwon [University of Ulsan, Ulsan (Korea, Republic of)

    2011-11-15

    FCS (fluorescence correlation spectroscopy) is a technique used to determine the dynamic characteristics of particles in solution and became common in the field of biophysics with the development of the confocal microscope, the high-speed photo-detector, and real-time data acquisition systems. In this study, the FCS system was composed of a commercial fluorescence microscope, a He-Ne laser (632.8 nm), a data acquisition board, and a software correlator written with LabVIEW. Autocorrelation functions were obtained using the measured fluorescence fluctuations of fluorescent beads and Q-dots (quantum dots) coated with carboxylate in distilled water. The diffusion coefficients of the beads and the Q-dots in distilled water and PBS (phosphate buffered saline) solution were obtained using the viscosity of water and the bead size. Also, using the bead size, we calculated the viscosity of the PBS solution, and we compared the Q-dots in water and in the PBS solution. The result showed that the viscosity of the PBS solution was 2.5 times greater than that of water, and that the sizes of Q-dots in water and PBS solution were one-third and one-sixth smaller than the known values, respectively, due to the pH variation in the solutions.

  6. APTES-modified RE2O3:Eu3+ luminescent beads: structure and properties.

    Science.gov (United States)

    Lechevallier, Séverine; Hammer, Peter; Caiut, José M A; Mazeres, Serge; Mauricot, Robert; Verelst, Marc; Dexpert, Hervé; Ribeiro, Sidney J L; Dexpert-Ghys, Jeannette

    2012-02-28

    Europium-doped lanthanide oxide RE(2)O(3):Eu(3+) (RE = Y or Gd) luminescent beads, with a spherical shape and a diameter of 150 ± 15 nm, have been modified by reaction with 3-aminopropyltriethoxysilane (APTES), in order to introduce reactive amine groups at their surfaces. The direct silanation has resulted in the formation of a nanometric layer at the surface of the beads, with an optimum grafting rate of 0.055 ± 0.005 mol APTES/mol RE(2)O(3). Fourier transform infrared (FTIR) and X-ray photoelectron (XPS) spectroscopies confirmed the condensation of an organosilane layer, made of cross-linked -O-Si-O-Si- and of groups -O-Si-R (with R = (CH(2))(3)NH(2) or O-Et). Titration of the accessible amine groups has been performed by simultaneously measuring the luminescence of grafted fluorescein isothiocyanate and that of core particles: there are about 2.3 × 10(4) (2.8 × 10(4)) -NH(2) per Y(2)O(3):Eu(3+) (Gd(2)O(3):Eu(3+)) bead. The isoelectronic point was shifted by one pH unit after APTES modification. The surface modification by APTES at least preserved (for Gd(2)O(3):Eu(3+)) or improved (for Y(2)O(3):Eu(3+)) the red emission of the beads. © 2012 American Chemical Society

  7. Biosorption of nonylphenol on dead biomass of Rhizopus arrhizus encapsulated in chitosan beads.

    Science.gov (United States)

    Lang, Weeranuch; Dejma, Chomawan; Sirisansaneeyakul, Sarote; Sakairi, Nobuo

    2009-12-01

    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 immobilised 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 using non-linear least-regression with the solver add-in in Microsoft Excel, correlated in order with the Fritz-Schluender>Redlich-Peterson>Freundlich>Langmuir isotherms. The pseudo first-order kinetics was found to have the best fit with the experimental data. The diffusivity of NP in the R. arrhizus-chitosan beads was calculated using the shrinking core model, and the diffusivity values were in the ranges of 2.3736x10(-4)-1.8950x10(-4) cm(2) s(-1). Desorption to recover the adsorbed NP from the beads was performed in methanol and was best described using a pseudo second-order kinetic model.

  8. Micromachined filter-chamber array with passive valves for biochemical assays on beads

    NARCIS (Netherlands)

    Lichtenberg, Jan; Verpoorte, Elisabeth; De Rooij, Nico F.

    2001-01-01

    The filter-chamber array presented here enables a real-time parallel analysis of three different samples on beads in a volume of 3 nL, on a 1 cm2chip. The filter-chamber array is a system containing three filter-chambers, three passive valves at the inlet channels and a common outlet. The design

  9. Model protein BSA adsorption onto novel magnetic chitosan/PVA/laponite RD hydrogel nanocomposite beads.

    Science.gov (United States)

    Mahdavinia, Gholam Reza; Soleymani, Moslem; Etemadi, Hossein; Sabzi, Mohammad; Atlasi, Ziba

    2017-09-20

    Chitosan-based magnetic beads were developed by solution-mixing method. Firstly, the Fe3O4 nanoparticles were in situ immobilized on laponite RD sheets. The magnetic laponite RD was then dispersed in PVA and mixed with chitosan solution. PVA was aimed to prevent the disintegration of chitosan under acidic media due to its ability to form hydrogel network through freezing-thawing method. The manufactured magnetic chitosan/PVA/laponite RD beads were utilized for adsorption study of a model protein, bovine serum albumin (BSA). The adsorption of BSA on beads was pH-dependent where smaller mass of protein was adsorbed at pH values lower than isoelectric point of BSA. Moreover, it was discovered that introduction of magnetic laponite RD can improve the adsorption capacity of magnetic beads for BSA in which hydrogel with the highest content of magnetic laponite RD demonstrated the maximum adsorption capacity for BSA (qm=240.5mg/g). Langmuir model described the isotherm data better than Freundlich model. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Mild disintegration of the green microalgae Chlorella vulgaris using bead milling

    NARCIS (Netherlands)

    Postma, P.R.; Miron, T.L.; Olivieri, G.; Barbosa, M.J.; Wijffels, R.H.; Eppink, M.H.M.

    2015-01-01

    In this work, the mild disintegration of the microalgae Chlorella vulgaris for the release of intracellular products has been studied. By means of bead milling the microalgae suspensions were successfully disintegrated at different biomass concentrations (25–145 gDW kg-1) over a range of agitator

  11. Enhanced biocatalytic esterification with lipase-immobilized chitosan/graphene oxide beads.

    Directory of Open Access Journals (Sweden)

    Siaw Cheng Lau

    Full Text Available In this work, lipase from Candida rugosa was immobilized onto chitosan/graphene oxide beads. This was to provide an enzyme-immobilizing carrier with excellent enzyme immobilization activity for an enzyme group requiring hydrophilicity on the immobilizing carrier. In addition, this work involved a process for the preparation of an enzymatically active product insoluble in a reaction medium consisting of lauric acid and oleyl alcohol as reactants and hexane as a solvent. This product enabled the stability of the enzyme under the working conditions and allowed the enzyme to be readily isolated from the support. In particular, this meant that an enzymatic reaction could be stopped by the simple mechanical separation of the "insoluble" enzyme from the reaction medium. Chitosan was incorporated with graphene oxide because the latter was able to enhance the physical strength of the chitosan beads by its superior mechanical integrity and low thermal conductivity. The X-ray diffraction pattern showed that the graphene oxide was successfully embedded within the structure of the chitosan. Further, the lipase incorporation on the beads was confirmed by a thermo-gravimetric analysis. The lipase immobilization on the beads involved the functionalization with coupling agents, N-hydroxysulfosuccinimide sodium (NHS and 1-ethyl-(3-dimethylaminopropyl carbodiimide (EDC, and it possessed a high enzyme activity of 64 U. The overall esterification conversion of the prepared product was 78% at 60 °C, and it attained conversions of 98% and 88% with commercially available lipozyme and novozyme, respectively, under similar experimental conditions.

  12. Detection of Escherichia coli O157:H7 using immuno beads

    Science.gov (United States)

    Tu, Shu-I.; Gehring, Andrew

    2005-11-01

    A new fluorescent sandwich method for the detection of Escherichia coli O157:H7 was developed. Strepavidin coated magnetic beads and fluorescence beads reacted with biotinylated anti E. coli O157 antibodies to form the immuno magnetic beads (IMB) and immuno fluorescence beads (IFB), respectively. The E. coli bacteria captured by IMB were further labeled with IFB to form IMBM-(E. coliO157:H7)N-IFBO sandwich complexes where the subscripts M, N and O were integral numbers. Using broth cultured E. coli O157:H7, the sandwich method was able to detect the bacteria at the level of ~ 103to 104 CFU/mL. Known quantity of freshly cultured E. coli O157:H7 cells were added to ground beef obtained from local markets. The bacteria in inoculated beef patties were enriched in EC broth containing novobiocin. After enriched for 4 h at 40 °C, the developed IMB-IFB method was applied to detect the presence of E. coli O157:H7. The results demonstrated that the developed method could detect the presence of 1 CFU of E. coli O157:H7 per gram of ground beef.

  13. Easily recoverable titanosilicate zeolite beads with hierarchical porosity: Preparation and application as oxidation catalysts

    NARCIS (Netherlands)

    Cheng, Wenjing; Jiang, Yanqiu; Xu, Xianzhu; Wang, Yan; Lin, Kaifeng; Pescarmona, Paolo P.

    2016-01-01

    Titanosilicate zeolite beads with hierarchical porosity and 0.2-0.5 mm diameter (HPB-TS-1) have been synthesized from a titanosilicate solution, employing a porous anion-exchange resin as shape- and structure-directing template. The characterization results showed the existence of crystalline TS-1

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

    Energy Technology Data Exchange (ETDEWEB)

    Rizzi, Giovanni, E-mail: giori@nanotech.dtu.dk; Østerberg, Frederik W.; Henriksen, Anders D.; Dufva, Martin; Hansen, Mikkel F., E-mail: mikkel.hansen@nanotech.dtu.dk

    2015-04-15

    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 differential sensor geometry. The sensor surfaces are functionalized with wild type (WT) and mutant type (MT) capture probes, differing by a single base insertion (a single nucleotide polymorphism, SNP). Complementary biotinylated targets in suspension couple streptavidin magnetic beads to the sensor surface. The beads are magnetized by the field arising from the bias current passed through the sensors. We demonstrate the first on-chip measurements of the melting of DNA hybrids upon a ramping of the temperature. This overcomes the limitation of using a single washing condition at constant temperature. Moreover, we demonstrate that a single sensor bridge can be used to genotype a SNP. - Highlights: • We apply magnetoresistive sensors to study solid-surface hybridization kinetics of DNA. • We measure DNA melting profiles for perfectly matching DNA duplexes and for a single base mismatch. • We present a procedure to correct for temperature dependencies of the sensor output. • We reliably extract melting temperatures for the DNA hybrids. • We demonstrate direct measurement of differential binding signal for two probes on a single sensor.

  15. Certain patterns of IgG adsorption by polystyrene bead surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Mamedov, M.K.

    1985-01-01

    The article reports on tests of domestic Soviet polystyrene beads that permit a simplified modification of the enzyme-adsorption method to identify the alpha hepatitis virus and its antibody in nonspecialized, general laboratories. Only patterns of Ig immunoglobulin adsorption were studied. Human IgG was conjugated with the radioactive isotope /sup 125/I by a chloramine method, with mean radioactivity and protein concentration measured frequently. Bovine serum albumin (BSA) and an anionic detergent Tween-20, and a phosphate-salt buffer with pH 5.8-8.2, were used to produce m-Ig and Ig. Adsorption involved incubation of the beads in various solutions, followed by measurement of their radioactivity. Results of several series of tests were subjected to Student-Fisher evaluation. This suggested that the presence of albumin in physiological concentrations in the solution had no important impact on m-Ig adsorption on the bead surface, which effectively adsorbed Ig from solutions without additional proteins, but also from Ig solutions containing serum albumin in physiological concentrations. Thus, it was possible to coat the beads with alpha Ig hepatitis virus. The Tween-20 weak detergent was effective for eliminating unwanted protein adsorption. 9 references, 3 figures.

  16. From Heavy Beads to Safety Pins: Adornment and Religiosity in Hindu Women’s Pote Practices

    NARCIS (Netherlands)

    Harris, T.; Sijapati, M.A.

    2016-01-01

    This article examines the object of the beaded necklace worn by married women in Nepal - called pote - and the ambiguities and layers of meaning surrounding pote in the lived worlds of the women who wear them. The ways women understand and use pote offer a view of religious belief as constituted and

  17. Rapid and effective DNA extraction method with bead grinding for a large amount of fungal DNA.

    Science.gov (United States)

    Watanabe, M; Lee, K; Goto, K; Kumagai, S; Sugita-Konishi, Y; Hara-Kudo, Y

    2010-06-01

    To identify a rapid method for extracting a large amount of DNA from fungi associated with food hygiene, extraction methods were compared using fungal pellets formed rapidly in liquid media. Combinations of physical and chemical methods or commercial kits were evaluated with 3 species of yeast, 10 species of ascomycetous molds, and 4 species of zygomycetous molds. Bead grinding was the physical method, followed by chemical methods involving sodium dodecyl sulfate (SDS), cetyl trimethyl ammonium bromide (CTAB), and benzyl chloride and two commercial kits. Quantity was calculated by UV absorbance at 260 nm, quality was determined by the ratio of UV absorbance at 260 and 280 nm, and gene amplifications and electrophoresis profiles of whole genomes were analyzed. Bead grinding with the SDS method was the most effective for DNA extraction for yeasts and ascomycetous molds, and bead grinding with the CTAB method was most effective with zygomycetous molds. For both groups of molds, bead grinding with the CTAB method was the best approach for DNA extraction. Because this combination also is relatively effective for yeasts, it can be used to extract a large amount of DNA from a wide range of fungi. The DNA extraction methods are useful for developing gene indexes to identify fungi with molecular techniques, such as DNA fingerprinting.

  18. Switchable bumps of a bead-embedded elastomer surface with variable adhesion.

    Science.gov (United States)

    Ohzono, T; Teraoka, K

    2017-12-13

    An extremely simple structural design of a composite material composed of an elastomer sheet and hard beads embedded at the surface is proposed to realize a shape-tunable surface; it reversibly forms bumps/undulations in response to in-plane tensile strain applied to the surface. Tribological properties such as adhesion therefore become switchable.

  19. studies on the properties of chitosan-starch beads and their ...

    African Journals Online (AJOL)

    DR. AMINU

    ABSTRACT. In this work, chitosan and blends of chitosan-starch beads were prepared and crosslinked with glutaraldehyde (pentane-1,5-dial). The blends were prepared with 1:1, 2:1 and 3:1 chitosan-starch ratios. Metformin hydrochloride (N,N-dimethylimidodicarbonimidic diamide hydrochloride), a type. 2 diabetis drug ...

  20. Characterization of antigen-specific B cells using nominal antigen-coated flow-beads.

    Directory of Open Access Journals (Sweden)

    Nicolas Degauque

    Full Text Available In order to characterize the reactivity of B cells against nominal antigens, a method based on the coupling of antigens onto the surface of fluorescent core polystyrene beads was developed. We first demonstrate that murine B cells with a human MOG-specific BCR are able to interact with MOG-coated beads and do not recognize beads coated with human albumin or pp65. B cells purified from human healthy volunteer blood or immunized individuals were tested for their ability to interact with various nominal antigens, including viral, vaccine, self and alloantigens, chosen for their usefulness in studying a variety of pathological processes. A substantial amount of B cells binding self-antigen MOG-coated beads can be detected in normal blood. Furthermore, greater frequencies of B cell against anti-Tetanic Toxin or anti-EBNA1 were observed in primed individuals. This method can reveal increased frequencies of anti-HLA committed B cells in patients with circulating anti-HLA antibodies compared to unsensitized patients and normal individuals. Of interest, those specific CD19 cells were preferentially identified within CD27(-IgD(+ (i-e naïve subset. These observations suggest that a broad range of medical situations could benefit from a tool that allows the detection, the quantification and the characterization of antigen-specific blood B cells.

  1. Pop-It Beads to Introduce Catalysis of Reaction Rate and Substrate Depletion Effects

    Science.gov (United States)

    Gehret, Austin U.

    2017-01-01

    A kinesthetic classroom activity was designed to help students understand enzyme activity and catalysis of reaction rate. Students served the role of enzymes by manipulating Pop-It Beads as the catalytic event. This activity illuminates the relationship between reaction rate and reaction progress by allowing students to experience first-hand the…

  2. [MRSA-infections-treatment with intraoperatively produced gentamycin-vancomycin PMMA beads].

    Science.gov (United States)

    Kelm, J; Anagnostakos, K; Regitz, T; Schmitt, E; Schneider, G; Ahlhelm, F

    2004-10-01

    We present gentamicin-vancomycin-impregnated beads that can be produced intraoperatively in moulds and demonstrated their successful use in ten cases of problematic Methicillin-resistant Staphylococcus aureus (MRSA) infection. To produce the antibiotically loaded PMMA beads, a two-part mould of polyoxymethylene was used. The mixture of PMMA and antibiotic is poured into the mould halves, and during polymerisation the halves bond together. The in vivo antibiotic concentrations of wound secretion from the redon drainage were measured by fluorescence-polarisation immunoassay, and a concentration/time function was determined. The PMMA beads (2 g of vancomycin plus 0.5 g of gentamicin plus 40 g of PMMA) were implanted in ten patients aged 41-76 years. In all ten patients, the infection was cured (follow-up 15 months). The combination of gentamicin and vancomycin in the PMMA of standardised beads represents a good alternative in the treatment of MRSA infections. Understanding of the mechanism of antibiotic release from PMMA allows differentiated dosing during systemic application.

  3. Compression of coated drug beads for sustained release tablet of glipizide: formulation, and dissolution.

    Science.gov (United States)

    Nguyen, Chien; Christensen, J Mark; Ayres, James W

    2014-02-01

    A promising glipizide formulation comprising compression of four-layer coated beads into tablets was prepared. The tablet offered the advantages of: a two-hour lag time before drug release, retaining sustained release characteristics and providing approximately zero-order drug release. Drug release was nearly independent of paddle speeds of 50 and 100 rpm releasing 80% over 14 h similar to the commercial glipizide osmotic pump tablet during dissolution testing while keeping the benefits of multiparticular dosage forms. The tablets contain beads with four layers: (1) the innermost layer consists of 2.5 g glipizide and 3.75 g solid ethylcellulose (Surelease®) coated onto 71.25 g of sugar beads; (2) next a hardening layer of 5 g of hypromellose; (3) the controlled release layer of 7.5 g of Surelease®:lactose at a solids ratio of 100:7 and (4) an outermost layer of 20 g of lactose:sodium starch glycolate (Explotab®) at a 2:1 ratio. Then, beads were compressed into tablets containing 11 mg of glipizide using 1500 lbs of compression pressure. The dissolution test similarity factor (f2) was above 50 for all test conditions for formulation F13 and Glucotrol® with a high of 69.9. The two Surelease® layers both aid controlling drug release, with the Surelease®-drug layer affecting drug release to a greater extent.

  4. In vitro affinity screening of protein and peptide binders by megavalent bead surface display.

    Science.gov (United States)

    Diamante, Letizia; Gatti-Lafranconi, Pietro; Schaerli, Yolanda; Hollfelder, Florian

    2013-10-01

    The advent of protein display systems has provided access to tailor-made protein binders by directed evolution. We introduce a new in vitro display system, bead surface display (BeSD), in which a gene is mounted on a bead via strong non-covalent (streptavidin/biotin) interactions and the corresponding protein is displayed via a covalent thioether bond on the DNA. In contrast to previous monovalent or low-copy bead display systems, multiple copies of the DNA and the protein or peptide of interest are displayed in defined quantities (up to 10(6) of each), so that flow cytometry can be used to obtain a measure of binding affinity. The utility of the BeSD in directed evolution is validated by library selections of randomized peptide sequences for binding to the anti-hemagglutinin (HA) antibody that proceed with enrichments in excess of 10(3) and lead to the isolation of high-affinity HA-tags within one round of flow cytometric screening. On-bead K(d) measurements suggest that the selected tags have affinities in the low nanomolar range. In contrast to other display systems (such as ribosome, mRNA and phage display) that are limited to affinity panning selections, BeSD possesses the ability to screen and rank binders by their affinity in vitro, a feature that hitherto has been exclusive to in vivo multivalent cell display systems (such as yeast display).

  5. The Effects of Anti-CD3/CD28 Coated Beads and IL-2 on Expanded T Cell for Immunotherapy.

    Science.gov (United States)

    Martkamchan, Sirimarn; Onlamoon, Nattawat; Wang, Siyu; Pattanapanyasat, Kovit; Ammaranond, Palanee

    2016-01-01

    The activation of peripheral blood mononucleated cells (PBMCs) with anti-CD3/CD28-coated magnetic beads promotes intrinsic resistance to HIV as well as cell expansion. The aim of this study was to define an optimal cell isolation protocol for the expansion of PBMCs using anti-CD3/CD28-coated bead stimulation, with the ultimate goal of using these cells for adoptive therapy. PBMCs were isolated from healthy donor blood samples. To determine the effect of varying the bead-to-cell ratios on the expansion rate and phenotypic characterization of the expanded cells, one million PBMCs were stimulated by anti-CD3/CD28-coated beads at bead-to-cell ratios of 0.1 : 1, 0.5 : 1 and 1.0 : 1 in the presence of 100 U/mL exogenous IL-2; also, one million PBMCs were stimulated by anti-CD3/CD28-coated beads at a bead-to-cell ratio of 0.5 : 1 in the presence of varying concentrations of IL-2 (20, 100 and 1000 U/mL). Cell expansion was carried out for three weeks. The cell numbers, cell viability and phenotypic characterization were determined by trypan blue exclusion and flow cytometry. The initial experiments showed no difference in the expansion rate from cells grown with the three different bead-to-cell ratios. PBMCs can be expanded up to 1000-fold at a 0.5 : 1 bead-to-cell ratio after three weeks of cell expansion with a high viability (90%). Furthermore, in the presence of 100 U/mL IL-2, the percentages of CD3-CD16+CD56+ cells showed marked increases. The results demonstrate that PBMCs were stimulated with anti-CD3/CD28-coated beads. This method may provide an alternative for driving T cell expansion, which may be very useful in adoptive immunotherapy.

  6. Enhancement of performance in porous bead-based microchip sensors: Effects of chip geometry on bio-agent capture.

    Science.gov (United States)

    Kulla, Eliona; Chou, Jie; Simmons, Glennon; Wong, Jorge; McRae, Michael P; Patel, Rushi; Floriano, Pierre N; Christodoulides, Nicolaos; Leach, Robin J; Thompson, Ian M; McDevitt, John T

    Measuring low concentrations of clinically-important biomarkers using porous bead-based lab-on-a-chip (LOC) platforms is critical for the successful implementation of point-of-care (POC) devices. One way to meet this objective is to optimize the geometry of the bead holder, referred to here as a micro-container. In this work, two geometric micro-containers were explored, the inverted pyramid frustum (PF) and the inverted clipped pyramid frustum (CPF). Finite element models of this bead array assay system were developed to optimize the micro-container and bead geometries for increased pressure, to increase analyte capture in porous bead-based fluorescence immunoassays. Custom micro-milled micro-container structures containing an inverted CPF geometry resulted in a 28% reduction in flow-through regions from traditional anisotropically-etched pyramidal geometry derived from Si-111 termination layers. This novel "reduced flow-through" design resulted in a 33% increase in analyte penetration into the bead and twofold increase in fluorescence signal intensity as demonstrated with C-Reactive Protein (CRP) antigen, an important biomarker of inflammation. A consequent twofold decrease in the limit of detection (LOD) and the limit of quantification (LOQ) of a proof-of-concept assay for the free isoform of Prostate-Specific Antigen (free PSA), an important biomarker for prostate cancer detection, is also presented. Furthermore, a 53% decrease in the bead diameter is shown to result in a 160% increase in pressure and 2.5-fold increase in signal, as estimated by COMSOL models and confirmed experimentally by epi-fluorescence microscopy. Such optimizations of the bead micro-container and bead geometries have the potential to significantly reduce the LODs and reagent costs for spatially programmed bead-based assay systems of this type.

  7. Polymer Conformation under Confinement

    Directory of Open Access Journals (Sweden)

    Stavros Bollas

    2017-02-01

    Full Text Available The conformation of polymer chains under confinement is investigated in intercalated polymer/layered silicate nanocomposites. Hydrophilic poly(ethylene oxide/sodium montmorillonite, PEO/Na+-MMT, hybrids were prepared utilizing melt intercalation with compositions where the polymer chains are mostly within the ~1 nm galleries of the inorganic material. The polymer chains are completely amorphous in all compositions even at temperatures where the bulk polymer is highly crystalline. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR is utilized to investigate the conformation of the polymer chains over a broad range of temperatures from below to much higher than the bulk polymer melting temperature. A systematic increase of the gauche conformation relatively to the trans is found with decreasing polymer content both for the C–C and the C–O bonds that exist along the PEO backbone indicating that the severe confinement and the proximity to the inorganic surfaces results in a more disordered state of the polymer.

  8. Antioxidant Stabilisation of Polymers

    Science.gov (United States)

    Shlyapnikov, Yurii A.

    1981-06-01

    Physicochemical aspects of the stabilisation of polymers are discussed. Attention is paid mainly to the aging and stabilisation of polymers under processing conditions. Topics considered are the kinetics and mechanism of the high-temperature oxidation of polymers, critical phenomena in the inhibited oxidation of polymers, the theory of synergism and antagonism among antioxidants, the reasons for differences in efficiency of antioxidants, and certain aspects of the relation between the efficiency of antioxidants and their molecular structure. A list of 132 references is included.

  9. Characterisation of polymers, 1

    CERN Document Server

    Crompton, Roy

    2008-01-01

    This essential guide to Polymer Characterisation is a complete compendium of methodologies that have evolved for the determination of the chemical composition of polymers. This 478-page book gives an up-to-date and thorough exposition of the state-of-the-art theories and availability of instrumentation needed to effect chemical and physical analysis of polymers. This is supported by approximately 1200 references. Volume 1 covers the methodology used for the determination of metals, non-metals and organic functional groups in polymers, and for the determination of the ratio in which different m

  10. Biopolymers Versus Synthetic Polymers

    Directory of Open Access Journals (Sweden)

    Florentina Adriana Cziple

    2008-10-01

    Full Text Available This paper present an overview of important synthetic and natural polymers with emphasis on polymer structure, the chemistry of polymer formation. an introduction to polymer characterization. The biodegradation process can take place aerobically and anaerobically with or without the presence of light. These factors allow for biodegradation even in landfill conditions which are normally inconducive to any degradation. The sheeting used to make these packages differs significantly from other “degradable plastics” in the market as it does not attempt to replace the current popular materials but instead enhances them by rendering them biodegradable.

  11. Artificial intelligence versus statistical modeling and optimization of continuous bead milling process for bacterial cell lysis

    Directory of Open Access Journals (Sweden)

    Shafiul Haque

    2016-11-01

    Full Text Available AbstractFor a commercially viable recombinant intracellular protein production process, efficient cell lysis and protein release is a major bottleneck. The recovery of recombinant protein, cholesterol oxidase (COD was studied in a continuous bead milling process. A full factorial Response Surface Model (RSM design was employed and compared to Artificial Neural Networks coupled with Genetic Algorithm (ANN-GA. Significant process variables, cell slurry feed rate (A, bead load (B, cell load (C and run time (D, were investigated and optimized for maximizing COD recovery. RSM predicted an optimum of feed rate of 310.73 mL/h, bead loading of 79.9% (v/v, cell loading OD600 nm of 74, and run time of 29.9 min with a recovery of ~3.2 g/L. ANN coupled with GA predicted a maximum COD recovery of ~3.5 g/L at an optimum feed rate (mL/h: 258.08, bead loading (%, v/v: 80%, cell loading (OD600 nm: 73.99, and run time of 32 min. An overall 3.7-fold increase in productivity is obtained when compared to a batch process. Optimization and comparison of statistical vs. artificial intelligence techniques in continuous bead milling process has been attempted for the very first time in our study. We were able to successfully represent the complex non-linear multivariable dependence of enzyme recovery on bead milling parameters. The quadratic second order response functions are not flexible enough to represent such complex non-linear dependence. ANN being a summation function of multiple layers are capable to represent complex non-linear dependence of variables in this case; enzyme recovery as a function of bead milling parameters. Since GA can even optimize discontinuous functions present study cites a perfect example of using machine learning (ANN in combination with evolutionary optimization (GA for representing undefined biological functions which is the case for common industrial processes involving biological moieties.

  12. Ultrasensitive direct competitive FLISA using highly luminescent quantum dot beads for tuning affinity of competing antigens to antibodies

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Sicheng; Zhou, Yaofeng; Huang, Xiaolin [State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047 (China); Yu, Ruijin [College of Science, Northwest A& F University, Yangling, Shaanxi 712100 (China); Lai, Weihua [State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047 (China); Xiong, Yonghua, E-mail: yhxiongchen@163.com [State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047 (China)

    2017-06-15

    Herein, for the first time we report a novel direct competitive fluorescence-linked immunosorbent assay (dcFLISA) for the ultrasensitive detection of ochratoxin A (OTA) by introducing a large size polymer beads loaded with quantum dots (QBs) as carrier of competing antigen for decreasing binding affinity to antibody and enhancing the fluorescent signal intensity. When using 255 nm QBs as carrier of competing antigen, the equilibrium dissociation constant of QB based competing antigen to antibodies can be tuned to 100 times higher than that of the horseradish peroxidase (HRP) based competing antigen by controlling labeled amounts of antigen on the surface of QBs. Various parameters that influenced the sensitivity of dcFLISA were investigated and optimized. Under optimum detection parameters, the dynamic linear range of developed dcFLISA for detecting OTA was established at 0.05 pg/mL to 1.56 pg/mL with a half maximal inhibitory concentration at 0.14 ± 0.04 pg/mL (n = 5), which is three orders of magnitude lower than that of conventional HRP-based dcELISA (0.24 ng/mL). The developed FLISA is also highly accurate, reliable, and shows no cross reaction to other mycotoxins. In summary, the proposed method offers a straightforward approach to improve the sensitivity of direct competitive immunoassay for trace small chemical molecule detection in food quality control, environmental monitoring, and clinical diagnosis. - Highlights: • Highly luminescent QBs were used as a carrier of competing antigen for ultrasensitive detection of OTA. • It is the first time to use a large size QBs as a carrier for tuning affinity of competing antigen to antibodies. • IC{sub 50} value of QB-based dcFLISA is three orders of magnitude lower than that of HRP-based dcELISA.

  13. A new beaded carbon molecular sieve sorbent for 222Rn monitoring.

    Science.gov (United States)

    Scarpitta, S C

    1996-05-01

    A new commercially available beaded carbon molecular sieve sorbent, Carboxen-564 (20/45 mesh), was tested and compared to Calgon-PCB (40/80) activated carbon for its adsorptive and desorptive characteristics under controlled conditions of temperature (25 degrees C) and relative humidity (RH). The amount of water vapor adsorbed by the beaded carbon molecular sieve material was typically a factor of 4 lower than the activated carbon, with a concomitant fourfold increase in the 222Rn adsorption coefficient, K(Rn). The maximum K(Rn) value for a thin layer of Carboxen-564, following a 2-d exposure at 40% RH, was 7.2 Bq kg(-1) per Bq m(-3). The K(Rn) or a 1-cm bed, following a 2-d exposure was 5.5 Bq m(-3), a 25% reduction. Under dynamic sampling conditions, where 0.4 g of the beaded carbon molecular sieve was contained in a 6 cm x 0.4 cm diameter tube, the maximum K(Rn) value was 6.5 Bq m(-3) after 2.5 h of sampling at 29% RH when the input flow rate was 4.2 x 10(-3) m3 h-1. Kinetic studies were also conducted under passive sampling conditions. The data show that the 222Rn buildup time-constant for a thin layer of the beaded carbon molecular sieve material was 1.3 h, whereas that of a 1 cm bed was 13 h. The 222Rn desorption time-constants, from gram amounts of the beaded carbon molecular sieve material into air and into a commercially available toluene based liquid scintillation cocktail, were 2 h and 3 h, respectively. Carboxen's high 222Rn adsorbing capacity, rapid kinetics, hydrophobicity and physical properties makes it an attractive alternative to other commercially available activated carbon used in passive and dynamic sampling devices.

  14. Peptide library synthesis on spectrally encoded beads for multiplexed protein/peptide bioassays

    Science.gov (United States)

    Nguyen, Huy Q.; Brower, Kara; Harink, Björn; Baxter, Brian; Thorn, Kurt S.; Fordyce, Polly M.

    2017-02-01

    Protein-peptide interactions are essential for cellular responses. Despite their importance, these interactions remain largely uncharacterized due to experimental challenges associated with their measurement. Current techniques (e.g. surface plasmon resonance, fluorescence polarization, and isothermal calorimetry) either require large amounts of purified material or direct fluorescent labeling, making high-throughput measurements laborious and expensive. In this report, we present a new technology for measuring antibody-peptide interactions in vitro that leverages spectrally encoded beads for biological multiplexing. Specific peptide sequences are synthesized directly on encoded beads with a 1:1 relationship between peptide sequence and embedded code, thereby making it possible to track many peptide sequences throughout the course of an experiment within a single small volume. We demonstrate the potential of these bead-bound peptide libraries by: (1) creating a set of 46 peptides composed of 3 commonly used epitope tags (myc, FLAG, and HA) and single amino-acid scanning mutants; (2) incubating with a mixture of fluorescently-labeled antimyc, anti-FLAG, and anti-HA antibodies; and (3) imaging these bead-bound libraries to simultaneously identify the embedded spectral code (and thus the sequence of the associated peptide) and quantify the amount of each antibody bound. To our knowledge, these data demonstrate the first customized peptide library synthesized directly on spectrally encoded beads. While the implementation of the technology provided here is a high-affinity antibody/protein interaction with a small code space, we believe this platform can be broadly applicable to any range of peptide screening applications, with the capability to multiplex into libraries of hundreds to thousands of peptides in a single assay.

  15. Structural evolution of chitosan–palygorskite composites and removal of aqueous lead by composite beads

    Energy Technology Data Exchange (ETDEWEB)

    Rusmin, Ruhaida, E-mail: ruhaida.rusmin@mymail.unisa.edu.au [CERAR – Centre for Environmental Risk Assessment and Remediation, Building X, University of South Australia, Mawson Lakes, SA 5095 (Australia); Faculty of Applied Sciences, Universiti Teknologi MARA Negeri Sembilan, Kuala Pilah 72000 (Malaysia); Sarkar, Binoy, E-mail: binoy.sarkar@unisa.edu.au [CERAR – Centre for Environmental Risk Assessment and Remediation, Building X, University of South Australia, Mawson Lakes, SA 5095 (Australia); CRC CARE – Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, P.O. Box 486, Salisbury, SA 5106 (Australia); Liu, Yanju [CERAR – Centre for Environmental Risk Assessment and Remediation, Building X, University of South Australia, Mawson Lakes, SA 5095 (Australia); CRC CARE – Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, P.O. Box 486, Salisbury, SA 5106 (Australia); McClure, Stuart [CERAR – Centre for Environmental Risk Assessment and Remediation, Building X, University of South Australia, Mawson Lakes, SA 5095 (Australia); Naidu, Ravi, E-mail: Ravi.Naidu@newcastle.edu.au [CERAR – Centre for Environmental Risk Assessment and Remediation, Building X, University of South Australia, Mawson Lakes, SA 5095 (Australia); CRC CARE – Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, P.O. Box 486, Salisbury, SA 5106 (Australia)

    2015-10-30

    Graphical abstract: - Highlights: • Facile preparation of chitosan–palygorskite composite beads demonstrated. • Components’ mass ratio impacted structural characteristics of composites. • Mechanism of composite formation and structure of composite beads proposed. • Composite beads adsorbed significantly greater amount of Pb than pristine materials. • In-depth investigation done on Pb adsorption mechanisms. - Abstract: This paper investigates the structural evolution of chitosan–palygorskite (CP) composites in relation to variable mass ratios of their individual components. The composite beads’ performance in lead (Pb) adsorption from aqueous solution was also examined. The composite beads were prepared through direct dispersion of chitosan and palygorskite at 1:1, 1:2 and 2:1 mass ratios (CP1, CP2 and C2P, respectively). Analyses by Fourier transform Infrared (FTIR) spectroscopy, Brunauer–Emmett–Teller (BET) surface area, X-ray diffraction (XRD) and scanning electron microscopy (SEM) confirmed the dependence of the composites’ structural characteristics on their composition mass ratio. The chitosan–palygorskite composite beads exhibited a better Pb adsorption performance than the pristine materials (201.5, 154.5, 147.1, 27.7 and 9.3 mg g{sup −1} for CP1, C2P, CP2, chitosan and palygorskite, respectively). Adsorption of Pb by CP1 and CP2 followed Freundlich isothermal model, while C2P fitted to Langmuir model. Kinetic studies showed that adsorption by all the composites fitted to the pseudo-second order model with pore diffusion also acting as a major rate governing step. The surface properties and specific interaction between chitosan and palygorskite in the composites were the most critical factors that influenced their capabilities in removing toxic metals from water.

  16. Deciphering complement interference in anti-human leukocyte antigen antibody detection with flow beads assays.

    Science.gov (United States)

    Visentin, Jonathan; Vigata, Margaux; Daburon, Sophie; Contin-Bordes, Cécile; Fremeaux-Bacchi, Véronique; Dromer, Claire; Billes, Marc-Alain; Neau-Cransac, Martine; Guidicelli, Gwendaline; Taupin, Jean-Luc

    2014-09-27

    Anti-human leukocyte antigen (HLA) antibody detection in solid-phase flow beads assays can be quenched by complement activation, but the precise mechanism of this interference is not fully elucidated yet. Using the Luminex flow beads screening assay for detection of anti-HLA antibodies, we analyzed the binding of high concentrations of the pan class I anti-HLA monoclonal antibody W6/32 in neat normal, ethylenediaminetetraacetic acid-treated normal and complement factors C1q, C4/C3, C2, C3, factor B or C5-depleted human sera, using anti-mouse immunoglobulin G as the detection antibody. Complement activation and binding to beads were revealed using anti-human C1q, C4d, and C3d antibodies. To translate our findings to the human setting, we used the class I and class II HLA single-antigen flow beads assays and sera from four patients with high titers of antibodies. Detection of W6/32 did not suffer any interference with C1q and C4/C3-depleted sera. A partial quenching was observed with C2, C3, and factor B-depleted sera, but was more pronounced with the factor B-depleted serum. W6/32 was undetectable in presence of C5-depleted serum. The binding of activation products derived from C3 principally, and also from C4, impaired immunoglobulin G and C1q detection. Accordingly, C4d detection was hindered by deposition of activated C3. Similar findings were obtained with patients' sera. Binding of C4 and C3 activation products is the main responsible for complement interference in flow beads assays. A complete quenching requires complement activation through C3 cleavage and its amplification by the alternative pathway.

  17. Viral RNA testing and automation on the bead-based CBNE detection microsystem.

    Energy Technology Data Exchange (ETDEWEB)

    Galambos, Paul C.; Bourdon, Christopher Jay; Farrell, Cara M.; Rossito, Paul (University of California at Davis); McClain, Jaime L.; Derzon, Mark Steven; Cullor, James Sterling (University of California at Davis); Rahimian, Kamayar

    2008-09-01

    We developed prototype chemistry for nucleic acid hybridization on our bead-based diagnostics platform and we established an automatable bead handling protocol capable of 50 part-per-billion (ppb) sensitivity. We are working towards a platform capable of parallel, rapid (10 minute), raw sample testing for orthogonal (in this case nucleic acid and immunoassays) identification of biological (and other) threats in a single sensor microsystem. In this LDRD we developed the nucleic acid chemistry required for nucleic acid hybridization. Our goal is to place a non-cell associated RNA virus (Bovine Viral Diarrhea, BVD) on the beads for raw sample testing. This key pre-requisite to showing orthogonality (nucleic acid measurements can be performed in parallel with immunoassay measurements). Orthogonal detection dramatically reduces false positives. We chose BVD because our collaborators (UC-Davis) can supply samples from persistently infected animals; and because proof-of-concept field testing can be performed with modification of the current technology platform at the UC Davis research station. Since BVD is a cattle-prone disease this research dovetails with earlier immunoassay work on Botulinum toxin simulant testing in raw milk samples. Demonstration of BVD RNA detection expands the repertoire of biological macromolecules that can be adapted to our bead-based detection. The resources of this late start LDRD were adequate to partially demonstrate the conjugation of the beads to the nucleic acids. It was never expected to be adequate for a full live virus test but to motivate that additional investment. In addition, we were able to reduce the LOD (Limit of Detection) for the botulinum toxin stimulant to 50 ppb from the earlier LOD of 1 ppm. A low LOD combined with orthogonal detection provides both low false negatives and low false positives. The logical follow-on steps to this LDRD research are to perform live virus identification as well as concurrent nucleic acid and

  18. Fluorescent Beads Are a Versatile Tool for Staging Caenorhabditis elegans in Different Life Histories

    Directory of Open Access Journals (Sweden)

    Liberta Nika

    2016-07-01

    Full Text Available Precise staging of Caenorhabditis elegans is essential for developmental studies in different environmental conditions. In favorable conditions, larvae develop continuously through four larval stages separated by molting periods. Distinguishing molting from intermolt larvae has been achieved using transgenes with molting reporters, therefore requiring strain constructions, or careful observation of individuals for pharyngeal pumping or behavioral quiescence. In unfavorable conditions, larvae can enter the stress-resistant and developmentally arrested dauer larva stage. Identifying dauer larvae has been based on their ability to withstand detergent selection, precluding identification of recovering animals or of mutants with defects in dauer morphogenesis. Here, we describe a simple method to distinguish molting larvae or dauer larvae from intermolt larvae that bypasses the limitations of current methods. Fluorescent latex beads are mixed with the bacterial food source and ingested by intermolt larvae and adults. Molting and dauer larvae do not feed, and therefore lack beads in their digestive tract. The presence of beads can be determined using a dissecting microscope at magnifications as low as 100 ×, or by using a wormsorter for high-throughput experiments. We find that continuously developing bead-lacking larvae display hallmarks of molting, including expression of the mlt-10::gfp molting marker and a lack of pharyngeal pumping. Furthermore, wild-type and mutant dauer larvae produced by any of three common methods are accurately identified by a lack of beads. Importantly, this method is effective in SDS-sensitive mutant backgrounds and can identify recovering dauer larvae, a stage for which there is no other method of positive selection.

  19. Binary Polymer Brushes of Strongly Immiscible Polymers.

    Science.gov (United States)

    Chu, Elza; Babar, Tashnia; Bruist, Michael F; Sidorenko, Alexander

    2015-06-17

    The phenomenon of microphase separation is an example of self-assembly in soft matter and has been observed in block copolymers (BCPs) and similar materials (i.e., supramolecular assemblies (SMAs) and homo/block copolymer blends (HBCs)). In this study, we use microphase separation to construct responsive polymer brushes that collapse to generate periodic surfaces. This is achieved by a chemical reaction between the minor block (10%, poly(4-vinylpyridine)) of the block copolymer and a substrate. The major block of polystyrene (PS) forms mosaic-like arrays of grafted patches that are 10-20 nm in size. Depending on the nature of the assembly (SMA, HBC, or neat BCP) and annealing method (exposure to vapors of different solvents or heating above the glass transition temperature), a range of "mosaic" brushes with different parameters can be obtained. Successive grafting of a secondary polymer (polyacrylamide, PAAm) results in the fabrication of binary polymer brushes (BPBs). Upon being exposed to specific selective solvents, BPBs may adopt different conformations. The surface tension and adhesion of the binary brush are governed by the polymer occupying the top stratum. The "mosaic" brush approach allows for a combination of strongly immiscible polymers in one brush. This facilitates substantial contrast in the surface properties upon switching, previously only possible for substrates composed of predetermined nanostructures. We also demonstrate a possible application of such PS/PAAm brushes in a tunable bioadhesion-bioadhesive (PS on top) or nonbioadhesive (PAAm on top) surface as revealed by Escherichia coli bacterial seeding.

  20. Doped Chiral Polymer Metamaterials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Doped Chiral Polymer Metamaterials (DCPM) with tunable resonance frequencies have been developed by adding plasmonic inclusions into chiral polymers with variable...