WorldWideScience

Sample records for bead walls

  1. Magnetic bead detection using domain wall-based nanosensor

    International Nuclear Information System (INIS)

    We investigate the effect of a single magnetic bead (MB) on the domain wall (DW) pinning/depinning fields of a DW trapped at the corner of an L-shaped magnetic nanodevice. DW propagation across the device is investigated using magnetoresistance measurements. DW pinning/depinning fields are characterized in as-prepared devices and after placement of a 1 μm-sized MB (Dynabeads® MyOne™) at the corner. The effect of the MB on the DW dynamics is seen as an increase in the depinning field for specific orientations of the device with respect to the external magnetic field. The shift of the depinning field, ΔBdep = 4.5–27.0 mT, is highly stable and reproducible, being significantly above the stochastic deviation which is about 0.5 mT. The shift in the deppinning field is inversely proportional to the device width and larger for small negative angles between the device and the external magnetic field. Thus, we demonstrate that DW-based devices can be successfully used for detection of single micron size MB

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

    DEFF Research Database (Denmark)

    Donolato, Marco; Vavassori, Paolo; Gobbi, Marco; Deryabina, Maria; Hansen, Mikkel Fougt; Metlushko, Vitali; Ilic, Bojan; Cantoni, Matteo; Petti, Daniela; Brivio, Stefano; Bertacco, Riccardo

    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...

  3. Chitin hydrolysis assisted by cell wall degrading enzymes immobilized of Thichoderma asperellum on totally cinnamoylated D-sorbitol beads

    International Nuclear Information System (INIS)

    In this study, cell wall degrading enzymes produced by Thrichoderma asperellum (TCWDE) were immobilized on totally cinnamoylated D-sorbitol (TCNSO) beads and used for chitin hydrolysis. In order to optimize immobilization efficiency, the reaction time was varied from 2 to 12 h and reactions were conducted in the presence or absence of Na2SO4. Immobilized enzymes were analysed concerning to thermal and operational stability. Immobilization in presence of Na2SO4 was 54% more efficient than immobilization in absence of salt. After optimization, 32% of the total enzyme offered was immobilized, with 100% of bounding efficiency, measured as the relation between protein and enzyme immobilized. Free and TCNSO–TCWDE presented very similar kinetics with maximum hydrolysis reached at 90 min of reaction. Thermal stability of both free and TCNSO–TCWDE was similar, with losses in activity after 55 °C. Moreover, free and TCNSO–TCWDE retained 100% activity after 3 h incubation at 55 °C. TCNSO–TCWDE were used in a bath-wise reactor during 14 cycles, producing 1825 μg of N-acetylglucosamine (NAG) maintaining 83% of initial activity. - Highlights: • TCWDE immobilized on TCNSO, a support with highly hydrophobic character • New immobilization strategy for immobilization on a hydrophobic support • TCNSO–TCWDE were retained during washes and during incubation at 55 °C for 3 h

  4. Chitin hydrolysis assisted by cell wall degrading enzymes immobilized of Thichoderma asperellum on totally cinnamoylated D-sorbitol beads

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Kátia F., E-mail: katia@icb.ufg.br [Departamento de Bioquímica e Biologia Molecular, Instituo de Ciências Biológicas, Universidade Federal de Goiás, Cx. Postal 131, 74001-970 Goiânia, GO (Brazil); Grupo de Química de Carbohidratos y Biotecnología de Alimentos (QCBA), Departamento de Química Orgánica, Facultad de Química, Universidad de Murcia, E-30100 Espinardo, Murcia (Spain); Cortijo-Triviño, David [Grupo de Química de Carbohidratos y Biotecnología de Alimentos (QCBA), Departamento de Química Orgánica, Facultad de Química, Universidad de Murcia, E-30100 Espinardo, Murcia (Spain); Batista, Karla A.; Ulhoa, Cirano J. [Departamento de Bioquímica e Biologia Molecular, Instituo de Ciências Biológicas, Universidade Federal de Goiás, Cx. Postal 131, 74001-970 Goiânia, GO (Brazil); García-Ruiz, Pedro A. [Grupo de Química de Carbohidratos y Biotecnología de Alimentos (QCBA), Departamento de Química Orgánica, Facultad de Química, Universidad de Murcia, E-30100 Espinardo, Murcia (Spain)

    2013-07-01

    In this study, cell wall degrading enzymes produced by Thrichoderma asperellum (TCWDE) were immobilized on totally cinnamoylated D-sorbitol (TCNSO) beads and used for chitin hydrolysis. In order to optimize immobilization efficiency, the reaction time was varied from 2 to 12 h and reactions were conducted in the presence or absence of Na{sub 2}SO{sub 4}. Immobilized enzymes were analysed concerning to thermal and operational stability. Immobilization in presence of Na{sub 2}SO{sub 4} was 54% more efficient than immobilization in absence of salt. After optimization, 32% of the total enzyme offered was immobilized, with 100% of bounding efficiency, measured as the relation between protein and enzyme immobilized. Free and TCNSO–TCWDE presented very similar kinetics with maximum hydrolysis reached at 90 min of reaction. Thermal stability of both free and TCNSO–TCWDE was similar, with losses in activity after 55 °C. Moreover, free and TCNSO–TCWDE retained 100% activity after 3 h incubation at 55 °C. TCNSO–TCWDE were used in a bath-wise reactor during 14 cycles, producing 1825 μg of N-acetylglucosamine (NAG) maintaining 83% of initial activity. - Highlights: • TCWDE immobilized on TCNSO, a support with highly hydrophobic character • New immobilization strategy for immobilization on a hydrophobic support • TCNSO–TCWDE were retained during washes and during incubation at 55 °C for 3 h.

  5. Sonocatalytical degradation enhancement for ibuprofen and sulfamethoxazole in the presence of glass beads and single-walled carbon nanotubes.

    Science.gov (United States)

    Al-Hamadani, Yasir A J; Chu, Kyoung Hoon; Flora, Joseph R V; Kim, Do-Hyung; Jang, Min; Sohn, Jinsik; Joo, Wanho; Yoon, Yeomin

    2016-09-01

    Sonocatalytic degradation experiments were carried out to determine the effects of glass beads (GBs) and single-walled carbon nanotubes (SWNTs) on ibuprofen (IBP) and sulfamethoxazole (SMX) removal using low and high ultrasonic frequencies (28 and 1000kHz). In the absence of catalysts, the sonochemical degradation at pH 7, optimum power of 0.18WmL(-1), and a temperature of 15°C was higher (79% and 72%) at 1000kHz than at 28kHz (45% and 33%) for IBP and SMX, respectively. At the low frequency (28kHz) H2O2 production increased significantly, from 10μM (no GBs) to 86μM in the presence of GBs (0.1mm, 10gL(-1)); however, no enhancement was achieved at 1000kHz. In contrast, the H2O2 production increased from 10μM (no SWNTs) to 31μM at 28kHz and from 82μM (no SWNTs) to 111μM at 1000kHz in the presence of SWNTs (45mgL(-1)). Thus, maximum removals of IBP and SMX were obtained in the presence of a combination of GBs and SWNTs at the low frequency (94% and 88%) for 60min contact time; however, >99% and 97% removals were achieved for 40 and 60min contact times at the high frequency for IBP and SMX, respectively. The results indicate that both IBP and SMX degradation followed pseudo-first-order kinetics. Additionally, the enhanced removal of IBP and SMX in the presence of catalysts was because GBs and SWNTs increased the number of free OH radicals due to ultrasonic irradiation and the adsorption capacity increase with SWNT dispersion. PMID:27150790

  6. 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 surrou

  7. Acupressure Bead in the Eustachian Tube.

    Science.gov (United States)

    Igarashi, Kazunori; Matsumoto, Yu; Kakigi, Akinobu

    2015-08-01

    In this article, we aim to enlighten practitioners and patients involved with acupressure beads and to contribute to their safer use by reporting a unique case of insidious intrusion of an acupressure bead into the eustachian tube. A metallic object was found in the eustachian tube of a patient while conducting a magnetic resonance imaging (MRI) examination. The object was later confirmed to be an auricular acupressure bead, and was successfully removed by performing a tympanoplasty and a canal wall down mastoidectomy. The bead was assumed to have passed through an existing perforation of the tympanic membrane. According to previously published literature, tympanic membrane perforations exist in ∼1% of the population. Therefore, middle-ear foreign bodies are relatively common occurrences for otolaryngologists. However, metallic objects such as acupressure beads are especially important in the sense that they can cause severe burns during MRI. To avoid potential complications, acupressure-bead practitioners should be aware of the possibility that intrusions through the tympanic membrane could go unnoticed. PMID:26276456

  8. In-bead screening

    DEFF Research Database (Denmark)

    2013-01-01

    The present invention relates to screening of one-bead-one-compound (OBOC) combinatorial libraries which is useful for the discovery of compounds displaying molecular interactions with a biological or a physicochemical system, such as substrates and inhibitors of enzymes and the like. The invention...... provides a method for screening a library of compounds for their interaction with a physico- chemical or biological system and a corresponding kit for performing the method of screening a one-bead-one-compound library of compounds....

  9. wall

    Directory of Open Access Journals (Sweden)

    Irshad Kashif

    2016-01-01

    Full Text Available Maintaining indoor climatic conditions of buildings compatible with the occupant comfort by consuming minimum energy, especially in a tropical climate becomes a challenging problem for researchers. This paper aims to investigate this problem by evaluating the effect of different kind of Photovoltaic Trombe wall system (PV-TW on thermal comfort, energy consumption and CO2 emission. A detailed simulation model of a single room building integrated with PV-TW was modelled using TRNSYS software. Results show that 14-35% PMV index and 26-38% PPD index reduces as system shifted from SPV-TW to DGPV-TW as compared to normal buildings. Thermal comfort indexes (PMV and PPD lie in the recommended range of ASHARE for both DPV-TW and DGPV-TW except for the few months when RH%, solar radiation intensity and ambient temperature were high. Moreover PVTW system significantly reduces energy consumption and CO2 emission of the building and also 2-4.8 °C of temperature differences between indoor and outdoor climate of building was examined.

  10. 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

    2016-05-01

    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. PMID:27058391

  11. 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.

  12. 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...

  13. 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.

  14. Gastroretentive delivery systems: hollow beads.

    Science.gov (United States)

    Talukder, R; Fassihi, R

    2004-04-01

    The objective of this study was to develop a floatable multiparticulate system with potential for intragastric sustained drug delivery. Cross-linked beads were made by using calcium and low methoxylated pectin (LMP), which is an anionic polysaccharide, and calcium, LMP, and sodium alginate. Beads were dried separately in an air convection type oven at 40 degrees C for 6 hours and in a freeze dryer to evaluate the changes in bead characteristics due to process variability. Riboflavin (B-2), tetracycline (TCN), and Methotrexate (MTX) were used as model drugs for encapsulation. Ionic and nonionic excipients were added to study their effects on the release profiles of the beads. The presence of noncross linking agents in low amounts (less than 2%) did not significantly interfere with release kinetics. For an amphoteric drug like TCN, which has pH dependent solubility, three different pHs (1.5, 5.0, and 8.0) of cross-linking media were used to evaluate the effects of pH on the drug entrapment capacity of the beads. As anticipated, highest entrapment was possible when cross-linking media pH coincided with least drug solubility. Evaluation of the drying process demonstrated that the freeze-dried beads remained buoyant over 12 hours in United States Pharmacopeia (USP) hydrochloride buffer at pH 1.5, whereas the air-dried beads remained submerged throughout the release study. Confocal laser microscopy revealed the presence of air-filled hollow spaces inside the freeze dried beads, which was responsible for the flotation property of the beads. However, the release kinetics from freeze dried beads was independent of hydrodynamic conditions. Calcium-pectinate-alginate beads released their contents at much faster rates than did calcium-pectinate beads (100% in 10 hours vs. 50% in 10 hours). It appears that the nature of cross-linking, drying method, drug solubility, and production approach are all important and provide the opportunity and potential for development of a

  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...

  16. Developement of Spherical Polyurethane Beads

    Institute of Scientific and Technical Information of China (English)

    K. Maeda; H. Ohmori; H. Gyotoku

    2005-01-01

    @@ 1Results and Discussion We established a new method to produce the spherical polyurethane beads which have narrower distribution of particle size. This narrower distribution was achieved by the polyurethane prepolymer which contains ketimine as a blocked chain-extending agent. Firstly, the prepolymer is dispersed into the aqueous solution containing surfactant. Secondaly, water comes into the inside of prepolymer as oil phase. Thirdly, ketimine is hydrolyzed to amine, and amine reacts with prepolymer immediately to be polyurethane.Our spherical polyurethane beads are very suitable for automotive interior parts especially for instrument panel cover sheet producing under the slush molding method, because of good process ability, excellent durability to the sunlight and mechanical properties at low temperature. See Fig. 1 ,Fig. 2 and Fig. 3 (Page 820).

  17. 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...

  18. Measurements of polystyrene bead trajectories and spatial distributions in a turbulent water flow, square duct using high-speed digital holography

    Science.gov (United States)

    van Hout, Rene; Rabencov, Boris; Arca, Javier

    2014-11-01

    Near neutrally buoyant, polystyrene beads (583 micrometers) were tracked in a square (50 × 50 mm2), closed-loop, turbulent water duct at a bulk flow Reynolds number of 10,602 (friction velocity 0.0208 m/s) using single view, inline digital holographic cinematography (at 1 kHz). The volume of interest (50 × 17.4 × 17.4 mm3) was positioned at the bottom part of the channel. The mean bead diameter normalized by inner wall coordinates was d+ = 14.2, with Stokes numbers of 8.5. In-house developed algorithms, fine-tuned to tracking single and overlapping beads were developed. Bead in-focus positions were determined by maximum intensity gradient method. Results showed that in agreement with literature publications, ascending beads lagged the mean streamwise water velocity while descending ones had similar velocities. Average streamwise bead velocities and number densities collapsed onto wall-normal-streamwise and spanwise-streamwise planes, indicated preferential segregation of ascending and descending beads up to a height of 100 wall units. Spanwise ``lane'' separation distances ranged between 150-200 wall units, larger but of the same order as the spanwise extent of coherent near-wall turbulence structures. Duct corners were nearly devoid of beads likely caused by secondary flows. Israel Science Foundation Grant 915/10 and COST Actions MP0806 and FP1005.

  19. Mesoporous zirconium titanium oxides. Part 2: Synthesis, porosity, and adsorption properties of beads.

    Science.gov (United States)

    Sizgek, G Devlet; Sizgek, Erden; Griffith, Christopher S; Luca, Vittorio

    2008-11-01

    Mesoporous zirconium titanium mixed-oxide beads having disordered wormhole textures and mole fractions of Zr (x) ranging from x=0.25 to 0.67 have been prepared. The bead preparation method combined the forced hydrolysis of mixtures of zirconium-titanium alkoxides in the presence of long-chain carboxylates with external gelation. Uniformly sized beads could be produced in the size range 0.5-1.1 mm by varying the droplet size and viscosity of the mixed-oxide sol, thus making them suitable for large-scale column chromatographic applications. The beads exhibited narrow pore size distributions with similar mean pore diameters of around 3.7 nm. The specific surface areas of the beads were linked to the Zr mole fraction in the precursor solution and were generally greater than 350 m2/g for x=0.5. A combination of scanning transmission electron microscopy and X-ray absorption fine structure analysis indicated that the pore walls of the beads were composed of atomically dispersed Zr and Ti to form a continuous network of Zr-O-Ti bonds. Mass transport in the beads was evaluated by monitoring the kinetics of vanadate and vanadyl adsorption at pH 10.5 and 0.87, respectively. PMID:18828618

  20. Beads, beaded-fibres and fibres: Tailoring the morphology of poly(caprolactone) using pressurised gyration.

    Science.gov (United States)

    Hong, Xianze; Edirisinghe, Mohan; Mahalingam, Suntharavathanan

    2016-12-01

    This work focuses on forming bead on string poly(caprolactone) (PCL) by using gyration under pressure. The fibre morphology of bead on string is an interesting feature that falls between bead-free fibres and droplets, and it could be effectively controlled by the rheological properties of spinning dopes and the major processing parameters of the pressurised gyration system which are working pressure and rotating speed. Bead products were not always spherical in shape and tended to be more elliptical, therefore both their width and length were measured. The average bead width and length produced spanned a range 145-660μm and 140-1060μm, respectively. The average distance between two adjacent beads (i.e. inter-bead distance) and the bead size (width and length) are shown to be a function of processing parameters and polymer concentration. An interesting morphology i.e. beads with short fibre was observed when using a high polymer concentration. Bead on string structure agglomeration was promoted by a low polymer concentration. Formation of droplets or agglomerated bead on string is promoted below 5wt% polymer concentration, and beads with short fibre were present in the microstructure beyond a polymer concentration of 20wt%. PMID:27612839

  1. 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.

  2. Porous bead packings for gas chromatography

    Science.gov (United States)

    Pollock, G. E.; Woeller, F. H.

    1979-01-01

    Porous polyaromatic packing beads have low polarity, high efficiency, short retention time, and may be synthesized in size range of 50 to 150 micrometers (100 to 270 mesh). Mechanically strong beads may be produced using various materials depending on elements and compounds to be identified.

  3. Nanohole 3D-size tailoring through polystyrene bead combustion during thin film deposition

    International Nuclear Information System (INIS)

    A novel approach is presented for nanohole 3D-size tailoring. The process starts with a monolayer of polystyrene (PS) beads spun coat on silicon wafer as a template. The holes can be directly prepared through combustion of PS beads by oxygen plasma during metal or oxide thin film deposition. The incoming particles are prevented from adhering on PS beads by H2O and CO2 generated from the combustion of the PS beads. The hole depth generally depends on the film thickness. The hole diameter can be tailored by the PS bead size, film deposition rate, and also the combustion speed of the PS beads. In this work, a series of holes with depth of 4-24 nm and diameter of 10-36 nm has been successfully prepared. The hole wall materials can be selected from metals such as Au or Pt and oxides such as SiO2 or Al2O3. These templates could be suitable for the preparation and characterization of novel nanodevices based on single quantum dots or single molecules, and could be extended to the studies of a wide range of coating materials and substrates with controlled hole depth and diameters.

  4. Integrated capture, transport, and magneto-mechanical resonant sensing of superparamagnetic microbeads using magnetic domain walls.

    Science.gov (United States)

    Rapoport, E; Montana, D; Beach, G S D

    2012-11-01

    An integrated platform for the capture, transport, and detection of individual superparamagnetic microbeads is described for lab-on-a-chip biomedical applications. Magnetic domain walls in magnetic tracks have previously been shown to be capable of capturing and transporting individual beads through a fluid at high speeds. Here it is shown that the strong magnetostatic interaction between a bead and a domain wall leads to a distinct magneto-mechanical resonance that reflects the susceptibility and hydrodynamic size of the trapped bead. Numerical and analytical modeling is used to quantitatively explain this resonance, and the magneto-mechanical resonant response under sinusoidal drive is experimentally characterized both optically and electrically. The observed bead resonance presents a new mechanism for microbead sensing and metrology. The dual functionality of domain walls as both bead carriers and sensors is a promising platform for the development of lab-on-a-bead technologies. PMID:22955796

  5. BeadArray expression analysis using bioconductor.

    Directory of Open Access Journals (Sweden)

    Matthew E Ritchie

    2011-12-01

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

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

    International Nuclear Information System (INIS)

    Additive manufacturing based on gas metal arc welding is an advanced technique for depositing fully dense components with low cost. Despite this fact, techniques to achieve accurate control and automation of the process have not yet been perfectly developed. The online measurement of the deposited bead geometry is a key problem for reliable control. In this work a passive vision-sensing system, comprising two cameras and composite filtering techniques, was proposed for real-time detection of the bead height and width through deposition of thin walls. The nozzle to the top surface distance was monitored for eliminating accumulated height errors during the multi-layer deposition process. Various image processing algorithms were applied and discussed for extracting feature parameters. A calibration procedure was presented for the monitoring system. Validation experiments confirmed the effectiveness of the online measurement system for bead geometry in layered additive manufacturing. (paper)

  7. Single bead-based electrochemical biosensor

    OpenAIRE

    LIU, CHANGCHUN; Schrlau, Michael G.; Bau, Haim H.

    2009-01-01

    A simple, robust, single bead-based electrochemical biosensor was fabricated and characterized. The sensor’s working electrode consists of an electrochemically-etched platinum wire, with a nominal diameter of 25 μm, hermetically heat-fusion sealed in a pulled glass capillary (micropipette). The sealing process does not require any epoxy or glue. A commercially available, densely functionalized agarose bead was mounted on the tip of the etched platinum wire. The use of a pre-functionalized bea...

  8. Prosopis alba exudate gum as excipient for improving fish oil stability in alginate-chitosan beads.

    Science.gov (United States)

    Vasile, Franco Emanuel; Romero, Ana María; Judis, María Alicia; Mazzobre, María Florencia

    2016-01-01

    The aim of the present work was to employ an exudate gum obtained from a South American wild tree (Prosopis alba), as wall material component to enhance the oxidative stability of fish oil encapsulated in alginate-chitosan beads. For this purpose, beads were vacuum-dried and stored under controlled conditions. Oxidation products, fatty acid profiles and lipid health indices were measured during storage. Alginate-chitosan interactions and the effect of gum were manifested in the FT-IR spectra. The inclusion of the gum in the gelation media allowed decreasing the oxidative damage during storage in comparison to the free oil and alginate-chitosan beads. The gum also improved wall material properties, providing higher oil retention during the drying step and subsequent storage. Fatty acids quality and lipid health indices were widely preserved in beads containing the gum. Present results showed a positive influence of the gum on oil encapsulation and stability, being the main mechanism attributed to a physical barrier effect. PMID:26213081

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

    Science.gov (United States)

    Dunlap, Dacey; Patrick, Patricia

    2012-01-01

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

  10. Beaded streams of Arctic permafrost landscapes

    Directory of Open Access Journals (Sweden)

    C. D. Arp

    2014-07-01

    Full Text Available 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

  11. Transport dynamics of superparamagnetic microbeads trapped by mobile magnetic domain walls

    Science.gov (United States)

    Rapoport, E.; Beach, G. S. D.

    2013-05-01

    The dynamics of fluid-borne superparamagnetic bead transport by field-driven domain walls (DWs) in submicrometer ferromagnetic tracks is studied experimentally together with numerical and analytical modeling. A combination of micromagnetic modeling and numerical calculation is used to determine the strength of bead-DW interaction for a range of track geometries and bead sizes. The maximum DW velocity for continuous bead transport is predicted from these results and shown to be supported by experimental measurements. Enhancement of the maximum velocity by appropriate material selection or field application is demonstrated, and an analysis of the source of statistical variation is presented. Finally, the dynamics of bead-DW interaction and bead transport above the maximum DW velocity for continuous DW-mediated bead transport is characterized.

  12. Black holes as beads on cosmic strings

    OpenAIRE

    Ashoorioon, Amjad; B. Mann, Robert

    2014-01-01

    We consider the possibility of formation of cosmic strings with black holes as beads. We focus on the simplest setup where two black holes are formed on a long cosmic string. It turns out the in absence of a background magnetic field and for observationally viable values for cosmic string tensions, $\\mu

  13. Metallic gold beads in hyaluronic acid

    DEFF Research Database (Denmark)

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

    2013-01-01

    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...... effects of hyaluronic acid....

  14. Motion of beads in an oscillatory rotating fluid: micro-bead-beating

    Science.gov (United States)

    Nadim, Ali; Sterling, James; Doebler, Robert

    2008-11-01

    One method for mechanical lysis of biological cells and spores is to mix them with a suspension of beads and vigorously ``shake'' the mixture. The precise mechanisms of lysis are not understood but lysis is thought to result from collisions between the beads and the cells and the associated stresses exerted on the cells. For instance, in the micro-bead-beater^TM instrument from Claremont BioSolutions LLC (Upland, CA), the ``shaking'' occurs when a small cartridge filled with a mixture of cells/spores and 100-micron beads is driven at high frequencies in a small arc trajectory. In this presentation, we describe our initial modeling effort aimed at understanding this system via analysis of the trajectories of beads within such an instrument. The equations governing the motion of non-neutrally-buoyant spherical beads in an oscillatory rotating flow are derived and analyzed numerically. The resulting trajectories are found to be quite complex and very different from those in a steadily rotating fluid. A catalog of possible trajectories at various values of the governing dimensionless parameters is presented.

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

    International Nuclear Information System (INIS)

    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.

  16. Small bowel obstruction due to ingested superabsorbent beads

    Directory of Open Access Journals (Sweden)

    Hao D. Pham

    2015-05-01

    Full Text Available Superabsorbent water beads have found many uses as household decorative items, crafts, and other industrial uses. We report a case of ingestion of several LiquiBlock Rainbow brand superabsorbent beads by a ten month old girl leading to small bowel obstruction requiring laparotomy and removal of the beads.

  17. Defect detection of the weld bead based on electromagnetic sensing

    International Nuclear Information System (INIS)

    Characterization of flaws of weld bead is imperative for high-quality welding. Methods of weld bead inspection include radiographic, ultrasonic and vision inspection. However, such methods are costly and time consuming. The proposed sensor is light, low-cost and fast. This paper summarizes our work on weld bead monitoring and defect detection using an electromagnetic sensor. Measurements are acquired in the form of S-Parameters, specifically measuring changes in the reflected coefficient S11. The weld bead is scanned using the sensor and any form of weld bead defection such as undercutting and excessive penetration is detected and identified.

  18. A novel adjuvant: polymerised serum albumin beads

    International Nuclear Information System (INIS)

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

  19. 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 an...... SiO2 performed better than polyethylene glycol-modified surfaces Two beads, Masterbeads and M-280 beads, were found to give superior results compared with other bead types. Antibody/ antigen interactions, Illustrated by C-reactive protein, were best performed with Masterbeads The results provide...... important information concerning the surface binding properties of streptavidin-functionalized beads and the immunomicroarray can be used when optimizing the performance of bead-based biosensors....

  20. Trivalent chromium sorption on alginate beads

    OpenAIRE

    Araújo, M. Manuela; Teixeira, J.A.

    1997-01-01

    The applicability of trivalent chromium removal from aqueous solutions using calcium alginate beads was studied. The equilibrium isotherms were plotted at two temperatures. The relationship between the chromium sorbed and the calcium released was determined as well as the effect of alginate amount and initial pH on the equilibrium results. Chromium sorption kinetics were evaluated as a function of chromium initial concentration and temperature. Transport properties of trival...

  1. RF Bead Pull Measurements of the DQW

    CERN Document Server

    Jaume, Guillaume

    2015-01-01

    This report was written within the framework of the CERN Summer Student Program. It is focused on the Radio Frequency study of the Double Quarter Wave Crab Cavity [1] considered for the crab-crossing scheme of the LHC Luminosity upgrade [2]. HFSS simulation [3] and Bead-Pull Measurements technique were used for the characterization of the higher-order terms of the main deflecting mode.

  2. Spray drying of bead resins: feasibility tests

    International Nuclear Information System (INIS)

    Rockwell International has developed a volume reduction system for low-level reactor wastes based on drying the wastes in a heated-air spray dryer. The drying of slurries of sodium sulfate, boric acid, and powdered ion exchange resins was demonstrated in previous tests. The drying of bead ion exchange resins can be especially difficult due to the relatively large size of bead resins (about 500 to 800 microns) and their natural affinity for water. This water becomes part of the pore structure of the resins and normally comprises 50 t 60 wt % of the resin weight. A 76-cm-diameter spray dryer was used for feasibility tests of spray drying of cation and anion bead resins. These resins were fed to the dryer in the as-received form (similar to dewatered resins) and as slurries. A dry, free-flowing product was produced in all the tests. The volume of the spray-dried product was one-half to one-third the volume of the as-received material. An economic analysis was made of the potential cost savings that can be achieved using the Rockwel spray dryer system. In-plant costs, transportation costs, and burial costs of spray-dried resins were compared to similar costs for disposal of dewatered resins. A typical utility producing 170 m3 (6,000 ft3) per year of dewatered resins can save $600,000 to $700,000 per year using this volume reduction system

  3. The Manufacture and Characterisation of Aluminium Foams Made by Investment Casting Using Dissolvable Spherical Sodium Chloride Bead Preforms

    Directory of Open Access Journals (Sweden)

    Andrew Kennedy

    2011-11-01

    Full Text Available Open cell Al foams have been made by infiltrating molten Al into preforms made from porous salt spheres. Infiltration has been effected using simple pressure-assisted vacuum investment casting where the maximum infiltration pressure difference was less than 36 psi. The preform and resulting foam density decreased with increasing compaction pressure and the foam density increased with increasing infiltration pressure. For low pressure infiltration, and high density preforms, salt dissolution was rapid due to the porous nature of the salt spheres. Infiltration of molten Al occurred into the beads and, for high density preforms and higher infiltration pressures, the volume of metal in the beads exceeded that in the cell walls, drastically decreasing the NaCl dissolution rate. A simple approach is shown whereby the data from mercury porosimetry can be used to predict the resulting foam density, thereby aiding the design of preform and beads structures.

  4. Cell Wall

    OpenAIRE

    Jamet, Elisabeth; Canut, Hervé; Boudart, Georges; Albenne, Cécile; Pont-Lezica, Rafael F

    2008-01-01

    This chapter covers our present knowledge of cell wall proteomics highlighting the distinctive features of cell walls and cell wall proteins in relation to problems encountered for protein extraction, separation and identification. It provides clues to design strategies for efficient cell wall proteomic studies. It gives an overview of the kinds of proteins that have yet been identified: the expected proteins vs the identified proteins. Finally, the new vision of the cell wall proteome, and t...

  5. Investigation the parameters for torsion ductility of bead wire

    International Nuclear Information System (INIS)

    Torsion testing is used to determine the quality of steel wire used for beads in pneumatic tires. However, strain aging (dynamic and static) caused by interstitial carbon and nitrogen atoms bound to mobile dislocations increases yield strength and decreases bead formability. Processing parameters of bead wire, such as line speed, lead bath temperature and wire diameter, were investigated, and theoretical calculations were made to estimate the effect of these parameters on strain aging. Nitrogen concentration was measured in bead wire samples with varying numbers of twists to failure during torsion testing. Surface morphologies of twisted bead wires were examined by scanning electron microscopy. Experimental data showed that torsional properties of bead wire were a function of stress relief temperature on and theoretical calculations showed that line speed and temperature have to be optimized for optimum torsion ductility.

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

    International Nuclear Information System (INIS)

    In the steel tube industry the word ''beading'' refers to a highly localised leak affecting the welded zone. During the pneumatic test its flow rate is generally very low no more than a few thousandths of a mm3/second. Detection of such a fault by this test is consequently slow, and those which are choked or at the limit of leakage may escape detection. For greater safety, the tube technician is now using non-destructive testing methods such as eddy-currents and ultrasonics

  7. Development of temper bead welding by under water laser welding

    International Nuclear Information System (INIS)

    Toshiba has developed temper bead welding by under water laser welding as SCC counter measure for aged components in PWR and BWR nuclear power plants. Temper bead welding by under water laser welding technique recovers toughness of low alloy steel reactor vessel by employing proper the number of cladding layers and their welding conditions. In this report, some evaluation results of material characteristics of temper bead welded low alloy steel are presented. (author)

  8. Artemisia arborescens L essential oil loaded beads: Preparation and characterization

    OpenAIRE

    Lai, Francesco; Loy, Giuseppe; Manconi, Maria; Manca, Maria Letizia; Fadda, Anna Maria

    2007-01-01

    The purpose of this work was to prepare sodium alginate beads as a device for the controlled release of essential oil for oral administration as an antiviral agent. Different formulations were prepared with sodium alginate as a natural polymer and calcium chloride or glutaraldehyde as a cross-linking agent. Loading capacities of between 86% and 100% were obtained in freshly prepared beads by changing exposure time to the cross-linking agent. Drying of the calcium alginate beads caused only a ...

  9. 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...

  10. Fast Drug Release Using Rotational Motion of Magnetic Gel Beads

    Directory of Open Access Journals (Sweden)

    Jun-Ichi Takimoto

    2008-03-01

    Full Text Available Accelerated drug release has been achieved by means of the fast rotation of magnetic gel beads. The magnetic gel bead consists of sodium alginate crosslinked by calcium chlorides, which contains barium ferrite of ferrimagnetic particles, and ketoprofen as a drug. The bead underwent rotational motion in response to rotational magnetic fields. In the case of bead without rotation, the amount of drug release into a phosphate buffer solution obeyed non-Fickian diffusion. The spontaneous drug release reached a saturation value of 0.90 mg at 25 minutes, which corresponds to 92% of the perfect release. The drug release was accelerated with increasing the rotation speed. The shortest time achieving the perfect release was approximately 3 minutes, which corresponds to 1/8 of the case without rotation. Simultaneous with the fast release, the bead collapsed probably due to the strong water flow surrounding the bead. The beads with high elasticity were hard to collapse and the fast release was not observed. Hence, the fast release of ketoprofen is triggered by the collapse of beads. Photographs of the collapse of beads, time profiles of the drug release, and a pulsatile release modulated by magnetic fields were presented.

  11. 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.

  12. Bead Capture on Magnetic Sensors in a Microfluidic System

    DEFF Research Database (Denmark)

    Østerberg, Frederik Westergaard; Dalslet, Bjarke Thomas; Damsgaard, Christian Danvad; Freitas, S. C.; Freitas, P. P.; Hansen, Mikkel Fougt

    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 that t...

  13. Random glycopeptide bead libraries for seromic biomarker discovery

    DEFF Research Database (Denmark)

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

    2010-01-01

    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...

  14. Black holes as beads on cosmic strings

    International Nuclear Information System (INIS)

    We consider the possibility of the formation of cosmic strings with black holes as beads. We focus on the simplest setup where two black holes are formed on a long cosmic string. It turns out that in the absence of a background magnetic field and for observationally viable values for cosmic string tensions, μ<2×10−7, the tension of the strut in between the black holes has to be less than the ones that run into infinity. This result does not change if a cosmological constant is present. However, if a background magnetic field is turned on, we can have stable setups where the tensions of all cosmic strings are equal. We derive the equilibrium conditions in each of these setups depending on whether the black holes are extremal or non-extremal. We obtain cosmologically acceptable solutions with solar mass black holes and an intragalactic-strength cosmic magnetic field. (paper)

  15. 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.

  16. A NOVEL APPROACH TO SYNTHESIZE CHITOSAN BEADS CROSSLINKED BY EPICHLOROHYDRIN

    Institute of Scientific and Technical Information of China (English)

    WANG Yongjian; BAI Shu; SUN Yan

    2001-01-01

    The present investigation describes a novel method for preparing spherical chitosan particles based on crosslinking with epichlorohydrin. Certain amount of pre-crosslinking agent was added to form chitosan gels by traditional inverse phase suspension polymerization. Then the gels were crosslinked by epichlorohydrin at basic condition to obtain chitosan beads. The effects of reaction conditions, such as crosslinking time, the amount of crosslinking agent and the NaOtt concentration,on the physical properties of the chitosan beads were investigated. The beads were found to have more amino groups in the polymer chains than the beads crosslinked by glutaraldehyde. The capacity for copper ions is as high as 40mg/g. The beads have good mechanical strength and can be reused.

  17. A NOVEL APPROACH TO SYNTHESIZE CHITOSAN BEADS CROSSLINKED BY EPICHLOROHYDRIN

    Institute of Scientific and Technical Information of China (English)

    WANGYongjina; BAIShu; 等

    2001-01-01

    The present investigation describes a novel method for preparing spherical chitosan particles based on crosslinking with epichlorohydrin.Certain amount of pre-crosslinking agent was added to form chitosan gels by traditional inverse phase suspension polymerization.Then the gels were crosslinked by epichlorohydrin at basic condition to obtain chitosan beads.The effects of reaction conditions,such as crosslinking time,the amount of crosslinking agent and the NaOH concentration,on the physical properties of the chitosan beads were investigated.The beads were found to have more amino groups in the polymer chains than the beads crosslinked by glutaraldehyde.The capacity for copper ions in as high as 40mg/g,The beads have good mechanical strength and can be reused.

  18. Design of systems for handling radioactive ion exchange resin beads

    International Nuclear Information System (INIS)

    The flow of slurries in pipes is a complex phenomenon. There are little slurry data available on which to base the design of systems for radioactive ion exchange resin beads and, as a result, the designs vary markedly in operating plants. With several plants on-line, the opportunity now exists to evaluate the designs of systems handling high activity spent resin beads. Results of testing at Robbins and Meyers Pump Division to quantify the behavior of resin bead slurries are presented. These tests evaluated the following slurry parameters; resin slurry velocity, pressure drop, bead degradation, and slurry concentration effects. A discussion of the general characteristics of resin bead slurries is presented along with a correlation to enable the designer to establish the proper flowrate for a given slurry composition and flow regime as a function of line size. Guidelines to follow in designing a resin handling system are presented

  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...... soft magnetic elements in the chip leads to a slightly higher capturing efficiency and a more uniform distribution of captured beads over the separation chamber than the system without soft magnetic elements.......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...

  20. Inhibitive Effect of antibiotic-loaded beads to cure chronic osteomyelitis in developing country : Hand-made vs commercial beads

    NARCIS (Netherlands)

    Rasyid, Hcrmawan N.; Van Horn, Jim R.; Van der Mei, Henny C.; Soegijoko, Sooegijardjo; Busscher, Henk J.; Neut, Danielle; Ibrahim, F; Osman, NAA; Usman, J; Kadri, NA

    2007-01-01

    Local antibiotic-loaded beads have been approved for standard treatment of orthopaedic pathogens, especially chronic osteomyelitis. Septopal (R), the only commercial local antibiotic bead available on the market, is expensive and contains only gentamicin. This study aimed to compare the in vitro inh

  1. 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

  2. Formulation of controlled release gellan gum macro beads of amoxicillin.

    Science.gov (United States)

    Babu, R Jayachandra; Sathigari, Sateesh; Kumar, M Thilek; Pandit, J K

    2010-01-01

    Gellan gum has been reported to have wide pharmaceutical applications such as tablet binder, disintegrant, gelling agent and as a controlled release polymer. Multiparticulate delivery systems spread out more uniformly in the gastrointestinal tract and reduce the local irritation. The purpose of this study is to explore possible applicability of gellan macro beads as an oral controlled release system of a sparingly soluble drug, amoxicillin. Gellan gum beads were prepared by ionotropic gelation with calcium ions. The effect of drug loading, stirring time, polymer concentration, electrolyte (CaCl2) concentration, curing time etc. influencing the preparation of the gellan gum macro beads and the drug release from gellan gum beads were investigated in this study. Optimal preparation conditions allowed very high incorporation efficiency for amoxicillin (91%) The release kinetics of amoxicillin from gellan beads followed the diffusion model for an inert porous matrix in the order: 0.1 N HCl > phosphate buffer > distilled water. Change in curing time did not significantly affect the release rate constant, but drug concentration, polymer concentration and electrolyte concentration significantly affect the release rate of amoxicillin from the beads. The gellan macro beads may be suitable for gastro retentive controlled delivery of amoxicillin. PMID:19863487

  3. 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.

  4. Self-organizing magnetic beads for biomedical applications

    International Nuclear Information System (INIS)

    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. - Highlights: ► We propose to use self-organized bead structures to isolate circulating tumor cells. ► Flexible ways are important to get a high probability of catching cancer cells. ► The beads make it possible to tune the geometry in size position and shape.

  5. 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...

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

    OpenAIRE

    Bu, Minqiang; Christensen, T. B.; Smistrup, Kristian; Wolff, Anders; Hansen, Mikkel Fougt

    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 soft magnetic elements in the chip leads to a slightly higher capturing efficiency and a more uniform distribution of captured beads over the separation chamber than the system without soft magnetic el...

  7. Ambiguous walls

    DEFF Research Database (Denmark)

    Mody, Astrid

    2012-01-01

    The introduction of Light Emitting Diodes (LEDs) in the built environment has encouraged myriad applications, often embedded in surfaces as an integrated part of the architecture. Thus the wall as responsive luminous skin is becoming, if not common, at least familiar. Taking into account how wall...

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

    International Nuclear Information System (INIS)

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

  9. 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

  10. Bead-releasing agents used in the preparation of solid samples as beads for WD-XRF measurement

    OpenAIRE

    Gazulla Barreda, María Fernanda; Barba Juan, Antonio; Orduña, Mónica; Rodrigo, Marta

    2008-01-01

    A study has been undertaken of bead-releasing agents that are widely used in preparing solid samples as fused beads for wavelength-dispersive X-ray fluorescence (WD-XRF)spectrometry measurement. The following bead-releasing agents were studied: NaI, LiBr, NH4I, and LiI. Each was incorporated in different quantities, as a solid and/or in an aqueous solution, together with a flux, into samples of ceramic raw materials. Release agent interference in the WD-XRF measurement was analyse...

  11. 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 ...

  12. Magnetic manipulation and sensing of beads for bioapplications

    DEFF Research Database (Denmark)

    Henriksen, Anders Dahl

    . It was found that a symmetric geometry with equal stripe width and spacing was optimal, and that the stripe period should be thrice the bead radius. Magnetophoretic bead velocities of 300 μm/s were measured, and selective separation based on differences in magnetophoretic mobility was hypothesized. However......, the fabricated magnetophoresis systems had two major limitations. First, protein-coated magnetic beads had a tendency to stick to the surface, even though multiple surface blockings and modifications were tried. Second, as the systems are fabricated using a single UV lithography step, the stripe width has...... measurements and is optimized for detecting small amounts of surface bound beads. The next study analyzes the thermal properties of the chip and setup. General methods for measuring or calculating the effective heat conductivity are given, along with a discussion on how to optimize this to facilitate the use...

  13. Archaeological study of ostrich eggshell beads collected from SDG site

    Institute of Scientific and Technical Information of China (English)

    WANG ChunXue; ZHANG Yue; GAO Xing; ZHANG XiaoLing; WANG HuiMin

    2009-01-01

    Ostrich eggshell beads and fragments collected from SDG site reflect primordial art and a kind of symbolic behavior of modern humans.Based on stratigraphic data and OSL dating,these ostrich eggshell beads are probably in Early Holocene (<10 ka BP).Two different prehistoric manufacturing pathways are usually used in the manufacture of ostrich eggshell beads in Upper Paleolithic.According to statistic analysis of the characteristics of ostrich eggshell beads,Pathway 1 is identified from these collections.In pathway 1,blanks are drilled prior to being trimmed to rough discs.They exhibit great potential for the study of the origin of primordial art and the development of ancient cultures and provide important data for studying behavioral options adopted by hominids in SDG area.In addition,they bear important implications for the origin of modern humans in East Asia.

  14. An approach to implement virtual channels for flowing magnetic beads

    International Nuclear Information System (INIS)

    This work demonstrates the feasibility of a novel microfluidic system with virtual channels formed by ‘walls’ of magnetic fields, including collecting channels, transporting channels and function channels. The channels are defined by the nickel patterns. With its own ferromagnetism, nickel can be magnetized using an external magnetic field; the nickel structures then generate magnetic fields that can either guide or trap magnetic beads. A glass substrate is sandwiched between the liquid containing magnetic beads and the chip with nickel structures, preventing the liquid from directly contacting the nickel. In this work, collecting channels, transporting channels and function channels are displayed sequentially. In the collecting channel portion, channels with different shapes are compared. Next, in the transporting channel portion we demonstrate I-, S- and Y-shaped channels can steer magnetic beads smoothly. Finally, in the function channel portion, a switchable trapping channel implemented with a bistable mechanism performs the passing and blocking of a magnetic bead. (paper)

  15. Simultaneous Immunofluorescent Detection of Coentrapped Cells in Gel Beads

    OpenAIRE

    Prioult, Guenolee; Lacroix, Christophe; Turcotte, Carl; Fliss, Ismaïl

    2000-01-01

    An immunofluorescent method involving double color labeling and confocal microscopy was reported to specifically detect lactic acid bacteria and probiotic cells coimmobilized in gels beads. The method described is rapid (4 h) and sensitive and may be useful for studying cell dynamics during mixed-culture starter production using immobilized cells in gel beads. Microscopic observations were perfectly correlated to cell counts obtained using a sandwich enzyme-linked immunosorbent assay.

  16. Configurational Statistics of Magnetic Bead Detection with Magnetoresistive Sensors

    DEFF Research Database (Denmark)

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

    2015-01-01

    Magnetic biosensors detect magnetic beads that, mediated by a target, have bound to a functionalized area. This area is often larger than the area of the sensor. Both the sign and magnitude of the average magnetic field experienced by the sensor from a magnetic bead depends on the location of the...... essential to sensor design. For illustration, we analyze three important published cases for which statistical fluctuations are dominant, significant, and insignificant, respectively....

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

    OpenAIRE

    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....

  18. Preparation of Bio-beads and Their Atrazine Degradation Characteristics

    Institute of Scientific and Technical Information of China (English)

    BI Hai-tao; ZHANG Lan-ying; LIU Na; ZHU Bo-lin

    2011-01-01

    Screened atrazine-mineralizing bacterium-Pseudomonas W4 was embedded inside an improved PVAH3BO3 embedment matrix to make bio-beads to degrade atrazine. The atrazine degradation characteristics were studied. The preparation procedure of bio-beads was as follows: (1) preparing a mixture of 100, 12.5, 10, 1.5 and 1 g/L PVA, bentonite(Ca), activated carbon powder, sodium alginate and centrifuged Pseudomonas W4 bacterium, respectively; (2) the mixture was dropped into a gently stirred cross linker solution(pH=6.7) and cured at 10 ℃ for 24 h.The optimal atrazine degradation conditions by bio-beads were as follows: pH=7, the auxiliary carbon source was glucose, and the concentration of glucose was greater than 325 mg/L. The bio-beads demonstrated stronger tolerance ability than the free microorganism to the increase of PCBs, hydrogen ion and hydroxide ion. SEM images show the uniform distribution of the microorganism inside bio-beads and the porous cross-linked structure of bio-beads which provides excellent mass transfer capacity.

  19. Reversing adhesion with light: a general method for functionalized bead release from cells.

    Science.gov (United States)

    Goulet-Hanssens, Alexis; Magdesian, Margaret H; Lopez-Ayon, G Monserratt; Grutter, Peter; Barrett, Christopher J

    2016-07-19

    Coated beads retain great importance in the study of cell adhesion and intracellular communication; we present a generally applicable method permitting spatiotemporal control of bead adhesion from cells. Herein we demonstrate in vitro release of a poly-d-lysine (PDL) layer from anionic polystyrene beads, allowing complete bead release from rat cortical neurons post-adhesion. PMID:27165466

  20. Preparation of styrene-co-4-vinylpyridine magnetic polymer beads by microwave irradiation for analysis of trace 24-epibrassinolide in plant samples using high performance liquid chromatography.

    Science.gov (United States)

    Zhang, Zhuomin; Zhang, Yi; Tan, Wei; Li, Gongke; Hu, Yuling

    2010-10-15

    In the study, a kind of novel styrene-co-4-vinylpyridine (St-co-4-VP) porous magnetic polymer beads was prepared by microwave irradiation using suspension polymerization. Microwave heating preparation greatly reduced the polymerization time to 1h. Physical characteristic tests suggested that these beads were cross-linking and possessed spherical shape, good magnetic response and porous morphologies with a narrow diameter distribution of 70-180 μm. Therefore, these beads displayed the long-term stability after undergoing 100-time extractions. Then, an analytical method for the determination of trace 24-epiBR in plant samples was developed by magnetic polymer bead extraction coupled with high performance liquid chromatography-fluorescence detection. St-co-4-VP magnetic polymer beads demonstrated the higher extraction selectivity for 24-epiBR than other reference compounds. Linear range was 10.00-100.0 μg/L with a relative standard deviation (RSD) of 6.7%, and the detection limit was 6.5 μg/kg. This analytical method was successfully applied to analyze the trace 24-epiBR in cole and breaking-wall rape pollen samples with recoveries of 77.2-90.0% and 72.3-83.4%, respectively, and RSDs were less than 4.1%. The amount of 24-epiBR in real breaking-wall rape pollen samples was found to be 26.2 μg/kg finally. This work proposed a sensitive, rapid, reliable and convenient analytical method for the determination of trace brassinosteroids in complicated plant samples by the use of St-co-4-VP magnetic polymer bead extraction coupled with chromatographic method. PMID:20846659

  1. The impact of functionalized CNT in the network of sodium alginate-based nanocomposite beads on the removal of Co(II) ions from aqueous solutions.

    Science.gov (United States)

    Karkeh-Abadi, Fatemeh; Saber-Samandari, Samaneh; Saber-Samandari, Saeed

    2016-07-15

    Significant efforts have been made to develop highly efficient adsorbents to remove radioactive Co(II) ion pollutants from medical and industrial wastewaters. In this study, amide group functionalized multi-walled carbon nanotube (CNT-CONH2) imprinted in the network of sodium alginate containing hydroxyapatite, and new nanocomposite beads were synthesized. Then, they were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). The prepared nanocomposite beads were used as an adsorbent of Co(II) ions from an aqueous solution. The presence and distribution of Co(II) ions in the surface of the nanocomposite beads was confirmed using FESEM, EDS and metal mapping analysis. The effect of various experimental conditions such as time, pH, and initial concentration of the adsorbate solution and temperature on the adsorption capacity of the nanocomposite beads were explored. The maximum Co(II) ions adsorption capacity of the prepared nanocomposite beads with the largest surface area of 163.4m(2)g(-1) was 347.8mgg(-1) in the optimized condition. The adsorption mechanism followed a pseudo-second-order kinetic model. Furthermore, the Freundlich appears to produce better fit than the Langmuir adsorption isotherm. Finally, thermodynamic studies suggest that endothermic adsorption process of Co(II) ions is spontaneous and thermodynamically favorable. PMID:27037477

  2. 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...... capture of beads by the magnetic fields near the sensor. It is shown that beads can be washed off the sensor surface....

  3. Use of the bead beater for preparation of Mycobacterium paratuberculosis template DNA in milk.

    Science.gov (United States)

    Odumeru, J; Gao, A; Chen, S; Raymond, M; Mutharia, L

    2001-10-01

    Mycobacterium paratuberculosis is a recognized chronic enteric pathogen that can affect many different species of animals, including primates. It has been suggested that this organism is associated with Crohn's disease in humans, and that milk is a potential source of human exposure to this organism. The limit of the detection of M. paratuberculosis in milk samples by direct PCR was 10(5) cfu/mL if the traditional boiling method was used for template DNA preparation. In this study, an improved method for template DNA preparation was examined. The method involves the use of a bead beater, which breaks up bacterial cell wall mechanically by vibrating bacteria with microbeads at high speed. The effectiveness of this method for lysing M. paratuberculosis cells was compared to that of the freeze-thaw method, and use of commercial kits such as the InstaGene Matrix and the QIAamp Tissue Kit. The bead beater procedure was tested in combination with various cell lysis and template DNA preparation procedures to determine which of these steps improved the limit of detection of PCR assay that amplifies a 413 bp fragment of the IS900 gene. Results showed that the use of the bead beater, in combination with the use of lysis buffer, boiling, and isopropanol precipitation, decreased the limit of detection of M. paratuberculosis in milk by the PCR to 10(2) cfu/mL. The limit of detection was further decreased to 10 cfu/mL when 0.0037% bovine serum albumin was included in the PCR reaction mixtures. The improved assay was 10- to 10(4)-fold more sensitive than the PCR assays using template DNA prepared by other lysis procedures including boiling alone, freeze-thaw plus boiling, or use of commercial kits for lysis. PMID:11768125

  4. Uranium sorption by Pseudomonas biomass immobilized in radiation polymerized polyacrylamide bio-beads.

    Science.gov (United States)

    D'Souza, S F; Sar, Pinaki; Kazy, Sufia K; Kubal, B S

    2006-01-01

    A Pseudomonas strain identified as a potent biosorbent of uranium (U) and thorium was immobilized in radiation-induced polyacrylamide matrix for its application in radionuclide containing wastewater treatment. The immobilized biomass exhibited a high U sorption of 202 mg g(-1) dry wt. with its optimum at pH 5.0. A good fit of experimental data to the Freundlich model suggested multilayered uranium binding with an affinity distribution among biomass metal binding sites. Scanning electron microscopy revealed a highly porous nature of the radiation-polymerized beads with bacterial cells mostly entrapped on pore walls. Energy dispersive X-ray analysis (EDXA) coupled with SEM ascertained the accumulation of uranium by the immobilized biomass without any physical damage to the cells. A significant (90%) part of biosorbed uranium was recovered using sodium bicarbonate with the immobilized biomass maintaining their U resorption capacity for multiple sorption-desorption cycles. Uranium loading and elution behavior of immobilized biomass evaluated within a continuous up-flow packed bed columnar reactor showed its effectiveness in removing uranium from low concentration (50 mg U L(-1)) followed by its recovery resulting in a 4-5-fold waste volume reduction. The data suggested the suitability of radiation polymerization in obtaining bacterial beads for metal removal and also the potential of Pseudomonas biomass in treatment of radionuclide containing waste streams. PMID:16484078

  5. Single bead detection with an NMR microcapillary probe

    Science.gov (United States)

    Nakashima, Yoshihiro; Boss, Michael; Russek, Stephen E.; Moreland, John

    2012-11-01

    We have developed a nuclear magnetic resonance (NMR) microcapillary probe for the detection of single magnetic microbeads. The geometry of the probe has been optimized so that the signal from the background water has a similar magnitude compared to the signal from the dephased water nearby a single magnetic bead within the probe detector coil. In addition, the RF field of the coil must be uniform within the effective range of the magnetic bead. Three different RF probes were tested in a 7 T (300 MHz) pulsed NMR spectrometer with sample volumes ranging from 5 nL down to 1 nL. The 1 nL probe had a single-shot signal-to-noise ratio (SNR) for pure water of 27 and a volume resolution that exhibits a 600-fold improvement over a conventional (5 mm tube) NMR probe with a sample volume of 18 μL. This allowed for the detection of a 1 μm magnetite/polystyrene bead (m = 2 × 10-14 A m2) with an estimated experimental SNR of 30. Simulations of the NMR spectra for the different coil geometries and positions of the bead within the coil were developed that include the B0 shift near a single bead, the inhomogeneity of the coils, the local coil sensitivity, the skin effect of the coil conductor, and quantitated estimates of the proximity effect between coil windings.

  6. Artemisia arborescens L essential oil loaded beads: preparation and characterization.

    Science.gov (United States)

    Lai, Francesco; Loy, Giuseppe; Manconi, Maria; Manca, Maria Letizia; Fadda, Anna Maria

    2007-01-01

    The purpose of this work was to prepare sodium alginate beads as a device for the controlled release of essential oil for oral administration as an antiviral agent. Different formulations were prepared with sodium alginate as a natural polymer and calcium chloride or glutaraldehyde as a cross-linking agent. Loading capacities of between 86% and 100% were obtained in freshly prepared beads by changing exposure time to the cross-linking agent. Drying of the calcium alginate beads caused only a slight decrease in the loading efficiency. The surface morphology of the different bead formulations were studied using scanning electron microscopy (SEM). Stability studies over a 3-month period showed that glutaraldehyde reacted with some components of Artemisia arborescens L essential oil, changing its composition. Calcium alginate beads showed an in vitro controlled release of the essential oil for the investigated 24 hours, while the use of glutaraldehyde as a cross-linking agent was found not appropriate because of the interactions with azulene derivatives and the low degree of matrix cross-linkage. PMID:17915817

  7. Development of multifunctional chitosan beads for fluoride removal

    International Nuclear Information System (INIS)

    Chitosan beads (CB) which have negligible defluoridation capacity (DC) have been chemically modified by introducing multifunctional groups, viz., NH3+ and COOH groups by means of protonation and carboxylation in order to utilize both amine and hydroxyl groups for fluoride removal. The protonated cum carboxylated chitosan beads (PCCB) showed a maximum DC of 1800 mg F-/kg whereas raw chitosan beads displayed only 52 mg F-/kg. Sorption process was found to be independent of pH and slightly influenced in the presence of other common anions. The fluoride sorption on modified forms was reasonably explained by Freundlich and Langmuir isotherms. The sorbents were characterised by FTIR and SEM with EDAX analysis. The sorption process follows pseudo-second-order and intraparticle diffusion kinetic models. The suitability of PCCB has been tested with field sample collected from a nearby fluoride endemic area.

  8. Towards hybrid swimming microrobots: bacteria assisted propulsion of polystyrene beads.

    Science.gov (United States)

    Behkam, Bahareh; Sitti, Metin

    2006-01-01

    Compactness and efficiency of biomotors makes them superior to man-made actuators and a very attractive choice of actuation for micro/nanorobots. However, biomotors are difficult to work with due to complications associated with their isolation and reconstitution. To circumvent this problem, here we use flagellar motors inside the intact cell of S. marcescens bacteria. An array of bacteria is used as propeller for a 10 microm polystyrene (PS) bead. PS bead is tracked for several seconds and its displacements is compared with diffusion length of a 10 microm particle. It is shown that the bead moves with an average velocity of 17 microm/s. Orientation of adhesion of S. marcescens to polydimethylsiloxane (PDMS) chips and microscale PS fibers was also investigated. It is shown that for both substrates; only bacteria from farther behind the leading edge of the swarm adhere in end-on configuration. PMID:17946113

  9. In vivo dynamics of GFRα1-positive spermatogonia stimulated by GDNF signals using a bead transplantation assay.

    Science.gov (United States)

    Uchida, Aya; Kishi, Kasane; Aiyama, Yoshimi; Miura, Kento; Takase, Hinako M; Suzuki, Hitomi; Kanai-Azuma, Masami; Iwamori, Tokuko; Kurohmaru, Masamichi; Tsunekawa, Naoki; Kanai, Yoshiakira

    2016-08-01

    In mouse testes, spermatogonial stem cells (SSCs), a subpopulation of GFRα1 (GDNF family receptor-α1)-positive spermatogonia, are widely distributed along the convoluted seminiferous tubules. The proliferation and differentiation of the SSCs are regulated in part by local expression of GDNF (glial cell-derived neurotorphic factor), one of major niche factors for SSCs. However, the in vivo dynamics of the GDNF-stimulated GFRα1-positive spermatogonia remains unclear. Here, we developed a simple method for transplanting DiI-labeled and GDNF-soaked beads into the mouse testicular interstitium. By using this method, we examined the dynamics of GFRα1-positive spermatogonia in the tubular walls close to the transplanted GDNF-soaked beads. The bead-derived GDNF signals were able to induce the stratified aggregate formation of GFRα1-positive undifferentiated spermatogonia by day 3 post-transplantation. Each aggregate consisted of tightly compacted Asingle and marginal Apaired-Aaligned GFRα1-positive spermatogonia and was surrounded by Aaligned GFRα1-negative spermatogonia at more advanced stages. These data not only provide in vivo evidence for the inductive roles of GDNF in forming a rapid aggregation of GFRα1-positive spermatogonia but also indicate the usefulness of this in vivo assay system of various growth factors for the stem/progenitor spermatogonia in mammalian spermatogenesis. PMID:27255992

  10. Dual stimuli-responsive smart beads that allow "on-off" manipulation of cancer cells.

    Science.gov (United States)

    Kim, Young-Jin; Kim, Soo Hyeon; Fujii, Teruo; Matsunaga, Yukiko T

    2016-06-24

    Temperature- and electric field-responsive polymer-conjugated polystyrene beads, termed smart beads, are designed to isolate cancer cells. In smart beads, the reversible "on-off" antigen-antibody reaction and dielectrophoresis force on an electrode are accomplished to realize "on-off" remote manipulation of smart beads and cancer cells. Both the zeta-potential and the hydrodynamic diameter of the smart beads are sensitive to temperature, allowing "on-off" reversible capture and release of cancer cells. Cancer cell-captured smart beads are then localized on electrodes by applying an electrical signal. PMID:27146341

  11. Half-bead weld repairs for in-service applications

    International Nuclear Information System (INIS)

    Successful half- or temper-bead technique weld repairs performed to Section XI of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code guidelines were made to two Heavy-Section Steel Technology Program vessels and a qualification prolongation. Intermediate sized vessels, equivalent in thickness to nuclear pressure vessels, were repair welded and subsequently flawed and pressure tested to approximately 21/4 times design pressure before leakage occurred. Discussed are the standards and procedures used with half-bead repairs, resultant induced metallurgical and stress effects, flaw test criterion, pressure test details and results, and recommendations for further development work for a speedier application process

  12. Corrosion of ancient glass beads found in Southern Thailand

    International Nuclear Information System (INIS)

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

  13. Interaction of peptide-bound beads with lipopolysaccharide and lipoproteins.

    Science.gov (United States)

    Suzuki, Masatsugu M; Matsumoto, Megumi; Omi, Hiroyuki; Kobayashi, Tomomi; Nakamura, Akio; Kishi, Hiroko; Kobayashi, Sei; Takagi, Takashi

    2014-05-01

    We previously reported the generation of lipopolysaccharide (LPS)-binding peptides by phage display and chemical modification. Among them, a dodecapeptide designated Li5-025 (K'YSSSISSIRAC'; K' and C' denote d-lysine and d-cysteine, respectively) showed a high binding affinity for LPS and was resistant to protease digestion (Suzuki et al., 2010). In the current study, Li5-025-bound silica beads, hereafter referred to as P-beads, were generated and found to be devoid of LPS-neutralizing activity. Thus, LPS bound to the P-beads could be directly used in the Limulus amebocyte lysate (LAL) assay. P-beads bound LPS dissolved in solutions of ethanol, pH4, pH10, and 0.5M NaCl and LPS bound to the P-beads was quantitatively assayed. The sensitivity of this assay was observed to be approximately 0.1pg/mL LPS. P-beads bound LPS dissolved in antithrombin III (AT III) solution which is a strong inhibitor of activated factors C and B as well as the clotting enzyme in the LAL assay; the inhibitory effect of AT III was completely reversed upon washing the P-beads with 25% acetonitrile. This was employed as the first step for the detection of free LPS in plasma using the LAL assay. LPS added to human plasma at 0°C followed by application to the P-beads and subsequent washing with 25% acetonitrile resulted in low LPS activity as detected by the LAL assay. However, further washing of the P-beads with 0.1% Triton X100 in 25% acetonitrile resulted in high LPS activity. This is the first instance of quantitative detection of free LPS in plasma using the LAL assay, and the sensitivity of this method was observed to be 1pg/mL of LPS. The proteins eluted in the 0.1% Triton X-100 wash were analyzed using sodium dodecyl sulfate polyacrylamide gel electrophoresis. Two protein bands of 28kDa and 18kDa were predominantly observed. Mass spectrometry analysis revealed that the 28kDa and 18kDa bands corresponded to apolipoprotein A-I (apoA-I) and apolipoprotein A-II (apoA-II), respectively. Apo

  14. Calcium pectinate gel beads obtained from callus cultures pectins as promising systems for colon-targeted drug delivery.

    Science.gov (United States)

    Günter, Elena A; Popeyko, Oxana V

    2016-08-20

    Low methyl-esterified pectins obtained from the cell walls of the campion (SV, SV>300), tansy (TV, TV>300) and duckweed (LM, LM>300) callus cultures and apple pectin (AP, Classic AU 701) were used as the carriers for colon delivery of prednisolone. The pectins with molecular weight more than 300kDa (SV>300, TV>300, LM>300) formed gels which exhibited the higher gel strength. The higher gel strength of these gels appeared to be related to the higher Mw and the lower degree of methylesterification (DE) of these pectins. Release aspects of prednisolone in the simulated gastric (pH 1.25), intestinal (pH 7.0) and colonic (pH 7.0+pectinase) media were investigated. The LM-5%, AP-3% and AP-5% beads destroyed in simulated intestinal medium probably due to the higher DE of the LM and AP pectins. The SV>300-3% and TV>300-3% prednisolone loaded bead systems showed a high stability at pH 1.25 and pH 7.0. Prednisolone release occurred in a larger extent in colonic medium due to the enzymatic erosion of the beads. The SV>300-3% and TV>300-3% particles showed a more controlled release that appeared to be related to the lower DE, rhamnogalacturonan content, rhamnogalacturonan I branching and the higher linearity and Mw of the TV>300 and SV>300 pectins, as well as to the higher gel strength. This in vitro study suggests that calcium pectinate gel beads obtained from callus cultures pectins can be proposed as potential systems for colon-targeted drug delivery. PMID:27178956

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

    International Nuclear Information System (INIS)

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

  16. Laccase-functionalized magnetic beads for biotechnology applications

    Czech Academy of Sciences Publication Activity Database

    Rotková, J.; Šuláková, R.; Zdražilová, P.; Korecká, L.; Jandová, M.; Lenfeld, Jiří; Horák, Daniel; Bílková, Z.

    Vancouver : University of British Columbia, 2008. s. 107. [International Conference on Scientific and Clinical Applications of Magnetic Carriers /7./. 20.05.2008-24.05.2008, Vancouver] Institutional research plan: CEZ:AV0Z40500505 Keywords : enzyme laccase * magnetic beads * biotechnology applications Subject RIV: CD - Macromolecular Chemistry

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

    Directory of Open Access Journals (Sweden)

    Teofilović Vesna

    2014-01-01

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

  18. Effects of Moving Side Walls on Confined Granular Packings

    Directory of Open Access Journals (Sweden)

    Ram Chand

    2011-07-01

    Full Text Available Granular materials have numerous industrial and geophysical applications. However, many phenomenon exhibited by granular media are not yet fully explained. Nowadays simulation has emerged as an important tool to investigate the complex properties exhibited by granular media. The influence of side walls movement of a granular column is investigated by discrete element, molecular dynamics simulations. The evolution of stress profile and deflection of vertical stresses is due to different bead sizes, coefficient of friction between grains and confining wall is investigated by using large-scale discrete element MD simulations in 3D. In such a configuration, it is found that apparent mass systemically increases with the increase in diameter of granules. As soon as the wall stops moving, the column attains equilibrium. The stress profiles are in good agreement with the Janssen form for high friction coefficient, while some deviations remain for smaller values of friction coefficient. The wall movement augments the number of particle-wall and particle-particle forces at the Coulomb criterion. The results indicate the variation in shielding of vertical stresses in granular column; it can be attributed to the fiction between the beads and the confining walls of the container.

  19. FORMULATION AND EVALUATION OF METFORMIN HYDROCHLORIDE BEADS BY IONOTROPIC GELATION TECHNIQUE

    Directory of Open Access Journals (Sweden)

    Ramteke K.H.

    2012-02-01

    Full Text Available The purpose of the present investigation was to incorporate Metformin hydrochloride into beads giving sustained release of metformin and optimize best cross linking agent amongst calcium and aluminium. Formulation was prepared by ionotropic external gelation technique using Ca+2 and Al+3 ions. The prepared beads were characterized for Entrapment efficiency, Scanning electron microscopy, Swelling kinetics, Release behavior of beads by Kinetics modeling. Ca+2 cross linked beads showed sustained release of drug for about 8 hr while Al+3 cross linked beads shown sustained release of drug about 10 hrs. The entrapment efficiency was also lesser in case of Ca+2 cross linked beads. The alginate beads swelled and eventually disintegrated in phosphate buffer (pH 6.8. The results revealed that aluminium is better cross linking agent than calcium indicating that valence affects cross linking. In nutshell, by proper choice of cross linking agent metformin hydrochloride can be incorporated into beads giving sustained release action.

  20. Manipulation of superparamagnetic beads using on-chip current lines placed on a ferrite magnet

    Science.gov (United States)

    Wang, Z. H.; Lew, W. S.; Bland, J. A. C.

    2006-04-01

    Manipulation of superparamagnetic beads in a static solution is demonstrated using on-chip current striplines placed on a ferrite magnet. The ferrite magnet fits the requirement to enhance the bead's magnetic moment while still keeping beads randomly dispersed in the liquid, so allowing easy and selective manipulation of single beads. By applying currents up to hundreds of milliampere, the tapered stripline first attracts the beads to its edge, then the magnetic force along the edge drives the trapped beads moving continuously towards the chip center. On arriving into the chip central area (a square zone which acts as a site to collect the arriving beads), fine manipulation of selected single beads is further performed by switching on/off and/or tuning the current passing through the nearby quadruple striplines. We suggest that the present system may provide a simple but effective platform for handling magnetic tags for biological and biomedical applications.

  1. Optical tweezers and manipulation of PMMA beads in various conditions

    Science.gov (United States)

    Kotsifaki, D. G.; Makropoulou, M.; Serafetinides, A. A.

    2009-07-01

    Laser optical trapping and micromanipulation of microparticles or cells and subcellular structures have gained remarkable interest in biomedical research and applications. Several laser sources are employed for the combination of a laser scalpel with an optical tweezers device, under microscopic control. However, although the principles and the mechanisms of pulsed laser ablation have been well described for macroscopic interventions, the microbeam operation, under microscopic guidance, necessitates further experiments and investigations. We present experimental results of controlled micro-ablation of PMMA beads of 3-8 μm diameters, trapped by laser tweezers in various media e.g. solutes of different index of refraction. An optical tweezers system, based on a continuous wave He-Ne laser emitting at 632.8 nm, was tested on beads and, despite the low power of the He-Ne laser, the optical trap was stable. Another optical system, based on a cw Nd:YAG laser emitting at 1.06 μm, was tested on microspheres too. Successful beads ablation was carried out by irradiation with multiple, or even a single nitrogen laser pulse of 7 ns pulse duration at a wavelength of 337 nm. The ablative perforation of the microspheres was estimated by controlling the laser fluence. Moreover, shape deformations of PMMA microspheres were observed. The experimentally obtained results are theoretically explained via the spatial intensity distribution based on Mie light scattering theory. Furthermore, the appearance of laser ablation holes in the back side of microspheres is explained by the ablation triggered shock waves propagation. The role of the stretching forces action is also discussed. Additionally, we report experimental results on measuring the optical trap force of PMMA beads. A powerful optical tweezers system based on a continuous wave Nd:YAG laser was used in order to estimate the trapping efficiency for several beads diameter.

  2. RADIOCHEMICAL STUDIES ON ALPHA FETOPROTEIN RADIOIMMUNOASSAY SOLID PHASE COATED BEADS

    International Nuclear Information System (INIS)

    Alpha fetoprotein (AFP) is a marker for hepatocellular and germ cell carcinoma. There are many different techniques used for measuring AFP in blood where the most accurate one is the immunoassay technique. The aim of the present study was to evaluate, optimize and prepare anti-AFP solid phase coated beads and use it for the determination of AFP in serum. The anti-AFP polyclonal antibodies were prepared by immunization of five rats with a highly purified AFP antigen and the anti-sera obtained were used for coating polystyrene beads to obtain the solid phase coated beads. Also, the AFP antigen was labelled with 125 I using chloramin-T (Ch-T) as oxidizing agent and the tracer obtained was purified using sephadex G-25 (PD-10) chromatography. The assay was performed using a set of AFP standards prepared by diluting the cord blood. The suitable conditions for coating process were obtained which include pH 8, molarity of coating buffer 0.05 M, volume of coating buffer 100 ml and dilution of antibody 1:1000 for coating 1000 beads. Because the coated beads prepared using borate buffer is more suitable than prepared using carbonate or phosphate buffers, they were chosen to complete the optimization and validation study. The optimization and characterization of the assay were performed to evaluate the quality of the proposed system. The system prepared proved a low cost, simple, sensitive and accurate results. The prepared system can be used to evaluate AFP in the blood and this will be helpful in diagnosing some diseases such as hepatocellular carcinoma and neural tube defects

  3. Novel chitosan goethite bionanocomposite beads for arsenic remediation.

    Science.gov (United States)

    He, Jing; Bardelli, Fabrizio; Gehin, Antoine; Silvester, Ewen; Charlet, Laurent

    2016-09-15

    We report on the synthesis and As adsorption properties of a novel chitosan - iron (oxyhydr)oxide composite material for the remediation of arsenic-contaminated water supplies. FE-SEM, Mössbauer spectroscopy, ICP-OES and synchrotron (Bulk XAS, μXRF) techniques were applied to determine the composition of the new material and investigate the As uptake efficiency and mechanism. The iron (oxyhydr)oxide phase has been identified as a nano-sized goethite, well dispersed in the chitosan matrix, leading to the name 'chitosan goethite bionanocomposite' (CGB). The CGB material is prepared in the form of beads of high density and excellent compression strength; the embedding of the goethite nanoparticles in the chitosan matrix allows for the high adsorption capacity of nanoparticles to be realized. CGB beads remove both As(III) and As(V) efficiently from water, over the pH range 5-9, negating the need for pre-oxidation of As(III). Kinetic studies and μXRF analysis of CGB bead sections show that diffusion-adsorption of As(V) into CGB beads is faster than for As(III). Using CGB beads, synthetic high-arsenic water (0.5 mg-As/L) could be purified to world drinking standard level (<0.01 mg-As/L) using only 1.4 g/L CGB. When considered in combination with the advantages of the low-cost of raw materials required, and facile (green) synthesis route, CGB is a promising material for arsenic remediation, particularly in developing countries, which suffer a diversity of socio-economical-traditional constraints for water purification and sanitation. PMID:27240296

  4. FORMULATION AND EVALUATION OF METFORMIN HYDROCHLORIDE BEADS BY IONOTROPIC GELATION TECHNIQUE

    OpenAIRE

    Ramteke K.H.; Vansola J.B.; Tailor D.J.; Parmar J. R.

    2012-01-01

    The purpose of the present investigation was to incorporate Metformin hydrochloride into beads giving sustained release of metformin and optimize best cross linking agent amongst calcium and aluminium. Formulation was prepared by ionotropic external gelation technique using Ca+2 and Al+3 ions. The prepared beads were characterized for Entrapment efficiency, Scanning electron microscopy, Swelling kinetics, Release behavior of beads by Kinetics modeling. Ca+2 cross linked beads showed sustained...

  5. A mathematical model for the formation of beaded fibers in electrospinning

    Directory of Open Access Journals (Sweden)

    Liu Zhi

    2015-01-01

    Full Text Available Beaded fibers are often observed in electrospinning. However, its formation mechanism is not well understood. A mathematical model for pulsation of the charged jets during spinning is proposed to reveal the phenomenon of beaded fibers, and the main factors for beaded fibers are elucidated.

  6. Application of the bead flush method to welded pipes to evaluate residual stresses nondestructively

    International Nuclear Information System (INIS)

    To assess the structural integrity of welded structures during the design and in-service inspection, it is important to evaluate welding residual stresses. Recently, the design process of structures has shifted from 'the design by rule' to 'the design by analysis' using the FEM (finite element method) codes. As the design process advances, analytical processes have formed a link in the chain of manufacturing and in-service inspection procedures. Under this circumstance, authors have proposed a new method called 'the Bead Flush Method', to evaluate the welding residual stresses by utilizing the FEM data constructed during the structural design. In this method, eigenstrains as sources of residual stresses are calculated from released elastic strains after removal of reinforcement of the weld by applying the inverse analysis. Then, residual stresses as well as displacements at any location concerned are evaluated by imposing eigenstrains as initial strains in the FEM analysis. Mechanical properties required through this analysis are the elastic constants at room temperature. No further properties, such as temperature dependencies of the yield strength and the thermal coefficient, are needed. By now, we have confirmed its utility for welded plates by computer simulations and experiments. In this study, further development of this method for application to welded pipes was attempted. Despite its relatively simple shape of pipes (axe symmetrical) compared with welded plates (3-dimentional), welded pipe problems are more complicated than those of welded plates from a view point of the inverse analysis. As a first step, a basic formulization was attempted to overcome this difficulty and future problems to be solved were made clear. Then computer simulations of the bead flush method conducted for a thin walled welded pipe confirmed its utility. Refs. 2 (author)

  7. Methodological Study of Cell Separation with Domestic Immunomagnetic Beads

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    To establish the method of cell separation with domestic immuomagnetic beads, three methods were investigated. Direct method, SPA method and Biotin-Avidin method were applied to separate cell strain Hut-78 and CD4 positive cells. Separation rate of strain Hut-78 was more than 90 % in direct method. Detachment rate with papain was over 95 %. Cell activity was well retained. SPA method and Biotin-Avidin methods were also effective, but the direct method was superior to the other two techniques. Before separated by the direct method, CD4 positive cells constituted 46.4 %±6.4 % of mononuclear cells (MNC), but in eliminated suspension there was only 6.2 %±2.3 % CD4 positive cells left. In the separated part, 80.6 %±7.2 % of the cells combined with the beads. It is concluded that the direct method in separating cells had high sensitivity and specificity.

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

    International Nuclear Information System (INIS)

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

  9. 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.

  10. Improved Recovery of Exfoliated Colonocytes from Feces Using Newly Developed Immunomagnetic Beads

    Directory of Open Access Journals (Sweden)

    Yoshikatsu Koga

    2008-01-01

    Full Text Available We demonstrated the feasibility of a new methodology for isolating colonocytes from feces. To reduce costs and improve the recovery rate of colonocytes from feces, we attempted to develop new immunomagnetic beads. Several sizes of magnetic beads were prepared and tagged with a monoclonal antibody against EpCAM. We made several new monoclonal antibodies against EpCAM, and each monoclonal antibody was tagged to the magnetic beads. In the simulation, the most efficient recovery of HT-29 cells was obtained using the smallest size of beads. Also, beads tagged with a monoclonal antibody with a higher affinity against EpCAM had a higher recovery rate. Similar results were obtained when the smallest size of beads with the highest-affinity monoclonal antibody was applied to clinical samples. The newly developed immunomagnetic beads may be useful for isolating colorectal cancer cells from feces, enabling the cytological or molecular biological diagnosis of CRC.

  11. Assessment of phytoplankton community dynamics using bead array technology

    OpenAIRE

    Yamamoto, Asako

    2010-01-01

    Molecular methods are becoming increasingly popular in the field of microbial ecology for the characterization of phytoplankton communities at the taxonomic level. However, many techniques lack the potential for large scale spatiotemporal studies due to limitations in their methodology. In this study, a high-throughput, rapid and cost effective hybridization-based bead assay was applied to two sets of samples : (1) a yearlong time series (March 2009-2010) of surface seawater samples taken off...

  12. 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.

  13. Diffusivity of Cu2+ in calcium alginate gel beads.

    Science.gov (United States)

    Jang, L K

    1994-01-20

    The diffusivity of Cu(2+) in calcium alginate beads calculated by the shrinking core model (SCM) was reevaluated in this work. The results obtained in this work were significantly different than those by the original authors. There were excellent agreements between the results obtained by the SCM in this work and those by the more rigorous linear absorption model (LAM) by the original authors. PMID:18615613

  14. Diffusivity of Cu2+ in calcium alginate gel beads: recalculation.

    Science.gov (United States)

    Lewandowski, Z; Roe, F

    1994-01-20

    Calculations of the diffusivity of Cu(2+) in calcium alginate gel beads using the shrinking core model were checked by us. Corrected results are reported here. Diffusivity was still found to increase with increasing alginate concentration, but at a lower rate than reported in the cited paper. The diffusivity increased by a factor of 2 over the range of alginate concentrations studied rather than 10. The original data is included with sample calculations. PMID:18615614

  15. THE PROBLEM OF CORRECT CHOICE OF FERRITE BEADS

    Directory of Open Access Journals (Sweden)

    Vladimir I. Gurevich

    2016-05-01

    Full Text Available A ferrite bead is a passive electrical element used to suppress high-frequency noise in electric circuits. This is one of the simplest and the cheapest type of filters. Thus, such filters are widely used in electric and electronic apparatus for both domestic and industrial purposes. It would seem that such a wide application of these elements suggests that methods for their correct selection and use are well-defined. However, this is not quite true.

  16. Elution of Metronidazole and Gentamicin from Polymethylmethacrylate Beads

    OpenAIRE

    Ramos, Jose Rafaelix

    2003-01-01

    Ten polymethylmethacrylate (PMMA) beads containing metronidazole (3 concentrations); gentamicin sulfate; or metronidazole and gentamicin sulfate were immersed in 5 ml of phosphate buffered saline in triplicate. Eluent was replaced at specified time intervals for 1 day (1, 3, 6, 12 and 24 hours), daily, or weekly for 21 days. Antibiotic concentrations were measured by high performance liquid chromatography. Changes in antibiotic bioactivity attributable to polymerization or co-polymerizatio...

  17. Chitosan and chemically modified chitosan beads for acid dyes sorption

    Institute of Scientific and Technical Information of China (English)

    AZLAN Kamari; WAN SAIME Wan Ngah; LAI KEN Liew

    2009-01-01

    The capabilities of chitosan and chitosan-EGDE (ethylene glycol diglycidyl ether) beads for removing Acid Red 37 (AR 37) and Acid Blue 25 (AB 25) from aqueous solution were examined. Chitosan beads were cross-linked with EGDE to enhance its chemical resistance and mechanical strength. Experiments were performed as a function of pH, agitation period and concentration of AR 37 and AB 25. It was shown that the adsorption capacities of chitosan were comparatively higher than chitosan-EGDE for both acid dyes. This is mainly because cross-linking using EGDE reduces the major adsorption sites -NH3+ on chitosan. Langmuir isotherm model showed best conformity compared to Freundlich and BET. The kinetic experimental data agreed very well to the pseudo second-order kinetic model. The desorption study revealed that after three cycles of adsorption and desorption by NaOH and HCl, both adsorbents retained their promising adsorption abilities. FT-IR analysis proved that the adsorption of acid dyes onto chitosan-based adsorbents was a physical adsorption. Results also showed that chitosan and chitosan-EGDE beads were favourable adsorbers and could be employed as low-cost alternatives for the removal of acid dyes in wastewater treatment.

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

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, H., E-mail: hahnh@bnl.gov [Collider–Accelerator Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Calaga, R. [Collider–Accelerator Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); European Organization for Nuclear Research, 1211 Geneva (Switzerland); Jain, Puneet; Johnson, Elliott C. [Physics and Astronomy Department, Stony Brook University, Stony Brook, NY 117943 (United States); Xu, Wencan [Collider–Accelerator Department, Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2014-01-11

    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≥10{sup 6} 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 S{sub 21} 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 results for HOMs in the first two dipole bands, the un-damped modes in the first quadrupole band, and the identification of several high-Q modes beyond.

  19. Diffusivity of Cu(2+) in calcium alginate gel beads.

    Science.gov (United States)

    Chen, D; Lewandowski, Z; Roe, F; Surapaneni, P

    1993-03-25

    A linear absorption model (LAM) is used to describe the process of metal binding to spherically shaped biopolymers particles. The LAM was solved using a numerical algorithm which calculates diffusivities of metal ion in biopolymer gels. It assumes attainment of rapid metal-biopolymer binding equilibrium accompanied by rate limiting diffusion of the metal ions through the gel. The model was tested using batch experiments in which copper (Cu(2+)) binding with calcium alginate beads was investigated. Biopolymer density in the beads was varied between 2% and 5%. The diffusion coefficient of Cu(2+) calculated from the LAM ranged from 1.19 x 10(-9) to 1.48 x 10(-9) m(2) s(-1) (average 1.31 +/- 0.21 x 10(-9) m(2) s(-1)), independent of biopolymer density. The LAM has theoretical advantages over the shrinking core model (shell progressive model). The latter calculated an unreasonable exponential increase in the diffusion coefficient as density of alginate polymer in the bead increased. PMID:18609618

  20. 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...

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

    International Nuclear Information System (INIS)

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

  2. Falling walls

    CERN Multimedia

    It was 20 years ago this week that the Berlin wall was opened for the first time since its construction began in 1961. Although the signs of a thaw had been in the air for some time, few predicted the speed of the change that would ensue. As members of the scientific community, we can take a moment to reflect on the role our field played in bringing East and West together. CERN’s collaboration with the East, primarily through links with the Joint Institute for Nuclear Research, JINR, in Dubna, Russia, is well documented. Less well known, however, is the role CERN played in bringing the scientists of East and West Germany together. As the Iron curtain was going up, particle physicists on both sides were already creating the conditions that would allow it to be torn down. Cold war historian Thomas Stange tells the story in his 2002 CERN Courier article. It was my privilege to be in Berlin on Monday, the anniversary of the wall’s opening, to take part in a conference entitled &lsquo...

  3. Preparation of Glutaraldehyde Cross-Linked Chitosan Beads Under Microwave Irradiation and Properties of Urease Immobilized onto the Beads

    Institute of Scientific and Technical Information of China (English)

    LIANG Zupei; FENG Yaqing; MENG Shuxian; ZHANG Weihong

    2005-01-01

    The glutaraldehyde cross-linked chitosan beads were prepared under microwave irradiation and urease was immobilized onto the beads. The activity and the yield of enzyme activity of the immobilized urease were 10.83 U/g carrier and 47.7%, respectively. The optimum conditions of immobilization were 1% of glutaraldehyde volume fraction, 10 mg/g of urease/beads weight ratio, 24 h of the processing time and pH 6.5 of the reaction medium for immobilization. The properties of the immobilized urease were investigated and compared with those of the free enzyme. The optimum pH values were 6.5 and 7.0 for the immobilized and free urease, respectively. The optimum temperature was 60 ℃ for the free urease, while it shifted to 65 ℃ for the immobilized enzyme. The Michaelis constant K m was 9.1 mmol/L for the immobilized and 12.5 mmol/L for the free urease. The immobilized urease retained 40% of its initial enzyme activity even after 10 repeated uses. The immobilized urease stored at 4 ℃ retained 46% of its initial activity even after 35 d.

  4. Adsorption of Cu and Mn on covalently cross-linked alginate gel beads.

    Science.gov (United States)

    Gotoh, Takeshi; Matsushima, Keiei; Kikuchi, Ken-Ichi

    2004-04-01

    The covalently cross-linked alginate gel beads were prepared by the reactions of Ca(2+)-doped alginate gel beads, which were formed by spraying a viscous alginate solution into a calcium chloride solution, with cyanogen bromide and following 1,6-diaminohexane. The cross-linking of alginate matrix decreased the mean bead diameter by about 30% and made the beads durable in some extent under alkaline conditions. The adsorption of metal ions on the covalently cross-linked alginate gel beads was rapid and reached at equilibrium within 30 min at 25 degrees C. Adsorption isotherms of Cu(II), Mn(II), and Ca2+ on the beads possessed a stepwise shape, which was firstly determined by Rorrer et al. [Ind. Eng. Chem. Res. 32 (1993) 2170] for cross-linked chitosan gel beads and explained by a pore-blockage mechanism. Higher selectivity was determined against Cu(II) over Mn(II) and Ca2+, especially at a low concentration region. These metal adsorption profiles for the covalently cross-linked alginate gel beads was almost the same as those for the un-cross-linked beads, indicating that the cross-linking reactions were performed without interfering the adsorption characteristics of alginate gel beads. PMID:14720547

  5. Entrapment of cross-linked cellulase colloids in alginate beads for hydrolysis of cellulose.

    Science.gov (United States)

    Nguyen, Le Truc; Lau, Yun Song; Yang, Kun-Lin

    2016-09-01

    Entrapment of enzymes in calcium alginate beads is a popular enzyme immobilization method. However, leaching of immobilized enzymes from the alginate beads is a common problem because enzyme molecules are much smaller than the pore size of alginate beads (∼200nm). To address this issue, we employ a millifluidic reactor to prepare cross-linked cellulase aggregate (XCA) colloids with a uniform size (∼300nm). Subsequently, these colloids are immobilized in calcium alginate beads as biocatalysts to hydrolyze cellulose substrates. By using fluorescent microscopy, we conclude that the immobilized XCA colloids distribute uniformly inside the beads and do not leach out from the beads after long-term incubation. Meanwhile, the pore size of the alginate beads is big enough for the cellulose substrates and fibers to diffuse into the beads for hydrolysis. For example, palm oil fiber and microcrystalline cellulose can be hydrolyzed within 48h and release reducing sugar concentrations up to 2.48±0.08g/l and 4.99±0.09g/l, respectively. Moreover, after 10 cycles of hydrolysis, 96.4% of the XCA colloids remain inside the alginate beads and retain 67% of the original activity. In contrast, free cellulase immobilized in the alginate beads loses its activity completely after 10 cycles. The strategy can also be used to prepare other types of cross-linked enzyme aggregates with high uniformity. PMID:27318817

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

    International Nuclear Information System (INIS)

    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 10-15 m2/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.

  7. Dose-response curve of a microfluidic magnetic bead-based surface coverage sandwich assay.

    Science.gov (United States)

    Cornaglia, Matteo; Trouillon, Raphaël; Tekin, H Cumhur; Lehnert, Thomas; Gijs, Martin A M

    2015-09-25

    Magnetic micro- and nanoparticles ('magnetic beads') have been used to advantage in many microfluidic devices for sensitive antigen (Ag) detection. Today, assays that use as read-out of the signal the number count of immobilized beads on a surface for quantification of a sample's analyte concentration have been among the most sensitive and have allowed protein detection lower than the fgmL(-1) concentration range. Recently, we have proposed in this category a magnetic bead surface coverage assay (Tekin et al., 2013 [1]), in which 'large' (2.8μm) antibody (Ab)-functionalized magnetic beads captured their Ag from a serum and these Ag-carrying beads were subsequently exposed to a surface pattern of fixed 'small' (1.0μm) Ab-coated magnetic beads. When the system was exposed to a magnetic induction field, the magnet dipole attractive interactions between the two bead types were used as a handle to approach both bead surfaces and assist with Ag-Ab immunocomplex formation, while unspecific binding (in absence of an Ag) of a large bead was reduced by exploiting viscous drag flow. The dose-response curve of this type of assay had two remarkable features: (i) its ability to detect an output signal (i.e. bead number count) for very low Ag concentrations, and (ii) an output signal of the assay that was non-linear with respect to Ag concentration. We explain here the observed dose-response curves and show that the type of interactions and the concept of our assay are in favour of detecting the lowest analyte concentrations (where typically either zero or one Ag is carried per large bead), while higher concentrations are less efficiently detected. We propose a random walk process for the Ag-carrying bead over the magnetic landscape of small beads and this model description explains the enhanced overall capture probability of this assay and its particular non-linear dose response curves. PMID:25817550

  8. Double-peaked edge-bead in drying film of solvent-resin mixtures

    Science.gov (United States)

    Shiratori, Suguru; Kubokawa, Toru

    2015-10-01

    A thick ridge of a film arising along the periphery of a substrate, which is the so-called edge-bead, is investigated experimentally and numerically for the case where the bead becomes double-peaked shape in direction away from the periphery of the substrate. It is clarified, by the optical measurement of thickness variations, that the double-peaked bead is separated from a single bead during the drying process, and after the separation, the inner bead moves inward. This motion of the bead is modeled by a lubrication-approximated flow equation, where the Laplace pressure and the solutocapillary effect are taken into account, coupled with the convective and diffusive mass transfer. The numerically simulated motion of the bead shows a good agreement with that obtained by the experiment, and it is revealed that the mechanism how the double-peaked edge-bead is formed. At the early stage of the drying process, a single bead is formed by the Laplace pressure due to the curvature along the substrate periphery. Along this single bead, the concentration gradient is caused by both the spatial distribution of the evaporation rate and the thickness effect on the change rate of the concentration, due to the fact that the resin concentration increases at a faster rate in the thin region. Consequently, the concentration distribution has a local minimum in the middle of the single bead, which drives oppositely directed solutocapillary flows and separates the bead. After the separation, the inner bead moves inward by a kind of a feed-forward mechanism, until the viscosity of the film becomes large enough to suppress the flow.

  9. Synthesis and activation of Immobilized beads by natural dye extracts

    Directory of Open Access Journals (Sweden)

    Singh Sanjay

    2012-03-01

    Full Text Available Immobilization technique is used for preservation of enzymes. Here we are using different colors of natural dye in this technique. Our major emphasis would be to create beads of different colors which will act as different carriers for essential enzymes. The need for using colorful dye is because when we need to preserve more than one enzyme then it is helpful in identification of that which enzyme is to be preserved and in which color. Here we used natural dye because most of the chemical dyes are carcinogenic in nature and may alter the nature of preserved enzyme. For this different plant products like mint leaf, rose petal, beat root and Carrot are used for the extraction of dye. In our research studies, we have identified, extracted, characterized, optimized and standardized the natural dyes from plant and microbial sources and we did a comparative study between natural dyes and artificial dyes with respect to different solvent systems like petroleum ether, diethyl ether, acetone, chloroform, ethanol and water systems. The extraction methodologies, characterization, MIC (minimum inhibitory concentration, and solubility studies will be discussed. These immobilization studies will help us to use this application in a variety of fields like in wine stabilization, in modifying the shelf life of food and other natural products which degrade quickly and are difficult to preserve under natural conditions. Here sodium Alginate beads are being used so that there is good number of beads formation and that will help for the proper entrapment of the essential enzymes required for an important reaction in Bio-systems.

  10. 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

  11. Butyl acetate synthesis using immobilized lipase in calcium alginate beads

    International Nuclear Information System (INIS)

    The esterification reaction of acetic acid and n-butanol using immobilized lipase encapsulated in calcium alginate beads (Lipase - CAB) and in chitosan coated calcium alginate beads (Lipase-CCAB) in n-hexane under mild reaction conditions were studied. Effects of temperature and substrate concentration (acetic acid and n-butanol) using Lipase - CAB, Lipase - CCAB and free lipase on the esterification reaction and their thermal stability towards esterification reaction were investigated. Results of temperature studies showed that the butyl acetate conversion increased with increase of temperature and reached the highest yield of about 70% around 50 degree Celsius for both immobilized systems but the yield of product catalyzed by free enzyme decreased as temperature was increased. Thermal stabilities studies showed that the Lipase-CCAB and Lipase-CAB were stable throughout the temperature range of 30-60 degree Celsius. However, free lipase became less stable at temperatures higher than 50 degree Celsius. The substrates, n-butanol and acetic acid exerted different effects on the esterification reaction and the reaction was favoured by higher acetic acid concentration than butanol. Kinetics parameters, Km and Vmax values for both substrates and the specific activities of the three enzyme system were also determined. The beads morphology was examined using SEM. Batch-wise operational stability studies for both immobilized systems demonstrated that the immobilized lipase performed better in the batch wise reactor system than the continuous bioreactor system and that the immobilized lipase remained active for at least 5 cycles of batch wise esterification reactions. (author)

  12. Optimization of weld bead geometry for stainless steel cladding deposited by GMAW.

    Directory of Open Access Journals (Sweden)

    P, Sreeraj

    2013-01-01

    Full Text Available The cladded components quality always depends on clad bead geometry and coefficient of shape of welds and dilution. In order to obtain better quality, good corrosion resistant properties and to reduce manufacturing costs the bead parameters must be optimized. The above objectives can be achieved by developing mathematical equations to predict bead geometry. This paper presents central composite rotatable design with full replication technique was used to obtain four critical dimensions of bead geometry. Thedeveloped models have been checked for adequacy and significance. The experiments were conducted by depositing Type ER-308L stainless steel wire on to IS-2062 structural steel plates. The results of confirmation experiments showed that the developed models can be able to predict bead geometry with reasonable accuracy. This study proved that both direct and interaction effect plays a major role in determining bead dimensions and dilution. The process parameters were optimized using response surface methodology (RSM.

  13. Non-destructive analysis of European cobalt blue glass trade beads

    International Nuclear Information System (INIS)

    Chemical analyses were made of royal blue glass trade beads from two early 17th century, archaeological sites in southern Ontario, Canada and from a glass beadmaking house in Amsterdam, The Netherlands. The results confirm that these beads were all mixed alkali - lime - silica glasses, coloured with Co and with opaque varients opacificed with Sn. The groupings by chemistry tend to segregate by bead shapes, so that oval beads group together and circular shaped beads group together. Although the 2 Canadian sites are about 190 km apart, they produced 2 different sets of oval beads of similar chemistry, possibly helping confirm the contemporaneity of the people at both sites. An As/Co atomic ratio of about two may fit with the possible source of Co as a cobalt-arsenide ore (of common name smaltite) from the Hartz Mountains of eastern Germany, a source not far from either Amsterdam or Venice, both well known glass beadmaking centres of the period. (author)

  14. Separation and recovery of palladium from acidic waste using dithiodiglycol-amide encapsulated polymeric beads

    International Nuclear Information System (INIS)

    Palladium selective ligand, N,N,N',N'-tetra-(2-ethylhexyl)-dithiodiglycolamide (DTDGA), was encapsulated in polymeric composite beads under simple laboratory conditions. The composite beads were evaluated for separation and recovery of palladium from acidic aqueous waste. The beads showed maximum uptake of Pd at 3.0 M HCl. Pd sorption kinetics was found to be fast and, the kinetics data fits well in to the pseudo second-order equation model for the sorption of palladium ions onto the composite beads. Different sorption isotherm models were applied to the experimental data. Equilibrium data are represented well by the Langmuir isotherm equation, with a monolayer sorption capacity of 1.56 mg/g for the swollen beads. Batch extraction studies showed negligible uptake of Fe, Cr, Ni, and Pt, thus showing very high selectivity and extractability of the composite beads for palladium. (author)

  15. Magnetic measurements of suspended functionalised ferromagnetic beads under DC applied fields

    International Nuclear Information System (INIS)

    In this work, a simple technique to obtain the hysteresis loops of magnetic beads (Spherotech Inc.) in liquid suspension is presented. The magnetic measurements were taken in a DC Magnetic Property Measurement System (MPMS-SQUID sensor). Samples were based on ferromagnetic beads (surface-functionalized NH2, mean diameter 4.32 μm) prepared in three conditions: dry, suspended in sucrose solution and in suspension after functionalization with fluorophore. Special small containers (1.3 cm long) made of non magnetic plastic were designed to hold the beads in liquid. The results indicate that the bead's remnant magnetization is half of the value at maximum applied field in all cases. However, due to the additional degrees of rotational freedom, beads suspended in a liquid do not present coercivity. The use of ferromagnetic beads and magnetic elements of different architectures for applications in bioassays is also discussed.

  16. Magnetic measurements of suspended functionalised ferromagnetic beads under DC applied fields

    Energy Technology Data Exchange (ETDEWEB)

    De Los Santos V, Luis [Cavendish Laboratory, University of Cambridge, J.J Thomson Avenue, Cambridge CB3 0HE (United Kingdom)], E-mail: luisitodv@yahoo.es; Llandro, Justin; Lee, Dongwook; Mitrelias, Thanos; Palfreyman, Justin J.; Hayward, Thomas J.; Cooper, Jos; Bland, J.A.C.; Barnes, Crispin H.W. [Cavendish Laboratory, University of Cambridge, J.J Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Arroyo C, Juan L. [Facultad de Quimica e Ingenieria Quimica, Universidad Nacional Mayor de San Marcos, Avenue Venezuela S/N, Lima 1 (Peru); Lees, Martin [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom)

    2009-07-15

    In this work, a simple technique to obtain the hysteresis loops of magnetic beads (Spherotech Inc.) in liquid suspension is presented. The magnetic measurements were taken in a DC Magnetic Property Measurement System (MPMS-SQUID sensor). Samples were based on ferromagnetic beads (surface-functionalized NH{sub 2}, mean diameter 4.32 {mu}m) prepared in three conditions: dry, suspended in sucrose solution and in suspension after functionalization with fluorophore. Special small containers (1.3 cm long) made of non magnetic plastic were designed to hold the beads in liquid. The results indicate that the bead's remnant magnetization is half of the value at maximum applied field in all cases. However, due to the additional degrees of rotational freedom, beads suspended in a liquid do not present coercivity. The use of ferromagnetic beads and magnetic elements of different architectures for applications in bioassays is also discussed.

  17. FUZZY REGRESSION MODEL TO PREDICT THE BEAD GEOMETRY IN THE ROBOTIC WELDING PROCESS

    Institute of Scientific and Technical Information of China (English)

    B.S. Sung; I.S. Kim; Y. Xue; H.H. Kim; Y.H. Cha

    2007-01-01

    Recently, there has been a rapid development in computer technology, which has in turn led todevelop the fully robotic welding system using artificial intelligence (AI) technology. However, therobotic welding system has not been achieved due to difficulties of the mathematical model andsensor technologies. The possibilities of the fuzzy regression method to predict the bead geometry,such as bead width, bead height, bead penetration and bead area in the robotic GMA (gas metalarc) welding process is presented. The approach, a well-known method to deal with the problemswith a high degree of fuzziness, is used to build the relationship between four process variablesand the four quality characteristics, respectively. Using these models, the proper prediction of theprocess variables for obtaining the optimal bead geometry can be determined.

  18. Spontaneous Liver Rupture After Treatment With Drug-Eluting Beads

    International Nuclear Information System (INIS)

    Spontaneous rupture of hepatocellular carcinoma (HCC) after transcatheter arterial chemoembolization (TACE) is a rare and life-threatening complication. Pathophysiologic mechanisms are not yet fully known; it is suggested that rupture is preceded by reactive tissue edema and intratumerous bleeding, leading to a rapid expansion of tumour mass with risk of extrahepatic bleeding in the case of subcapsular localisation. This case report discusses a sudden, unexpected lethal complication in a 74 year-old male patient treated with TACE using DC Bead loaded with doxorubicin (DEBDOX) in a progressive multifocal HCC.

  19. Interrogating DNA-protein interactions with magnetic beads

    Czech Academy of Sciences Publication Activity Database

    Fojta, Miroslav; Pivoňková, Hana; Němcová, Kateřina; Šebest, Peter; Havran, Luděk; Pečinka, Petr; Brázdová Jagelská, Eva; Brázdová, Marie; Brázda, Václav

    Linz, 2009. s. 98. [Regional Biophysics Conference 2009. 10.02.2009-14.02.2009, Linz] R&D Projects: GA AV ČR(CZ) IAA500040701; GA AV ČR(CZ) 1QS500040581; GA ČR(CZ) GP204/07/P476; GA MŠk(CZ) LC06035 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : magnetic beads * DNA-protein interaction * p53 -family proteins Subject RIV: BO - Biophysics

  20. Metallurgical investigation of wire breakage of tyre bead grade

    OpenAIRE

    Piyas Palit; Souvik Das; Jitendra Mathur

    2015-01-01

    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 f...

  1. Synthesis and activation of Immobilized beads by natural dye extracts

    OpenAIRE

    Singh Sanjay; Amod Kumar; SUNEETHA V; Bishwambhar Mishra; Gopinath R; Sharad Yadav; Bhaskar Mitra

    2012-01-01

    Immobilization technique is used for preservation of enzymes. Here we are using different colors of natural dye in this technique. Our major emphasis would be to create beads of different colors which will act as different carriers for essential enzymes. The need for using colorful dye is because when we need to preserve more than one enzyme then it is helpful in identification of that which enzyme is to be preserved and in which color. Here we used natural dye because most of the chemical dy...

  2. Design and Evaluation of Stomach-Specific Drug Delivery of Domperidone using Floating Pectin Beads

    OpenAIRE

    K.Varun Kumar; P. Srikanth Choudary; Ajaykumar. B

    2013-01-01

    The objective of present study was to develop floating beads of Domperidone (DOM) in order to increase its residence time in the stomach without contact with the mucosa, improve patient compliance and obtain improved therapeutic efficacy. They are prepared by extrusion congealing technique with pectin as a polymer. Floating beads were characterized by polymer compatibility by using FT-IR. The prepared beads were evaluated for particle size, surface morphology, buoyancy, actual drug content, e...

  3. Microfluidic immunomagnetic multi-target sorting--a model for controlling deflection of paramagnetic beads.

    Science.gov (United States)

    Tsai, Scott S H; Griffiths, Ian M; Stone, Howard A

    2011-08-01

    We describe a microfluidic system that uses a magnetic field to sort paramagnetic beads by deflecting them in the direction normal to the flow. In the experiments we systematically study the dependence of the beads' deflection on bead size and susceptibility, magnet strength, fluid speed and viscosity, and device geometry. We also develop a design parameter that can aid in the design of microfluidic devices for immunomagnetic multi-target sorting. PMID:21677937

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

    OpenAIRE

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

  5. AcGFP and mCherry Calibration Beads for Flow Cytometry

    Science.gov (United States)

    Vierra, M.; Garachtchenko, T.; Gupta, V.; Schmid, I.; Hawley, T.; Cimbro, R.; Farmer, A.; Haugwitz, M.

    2014-01-01

    Analysis of cells via flow cytometry requires calibration of the instrument with the fluorophore used to label the cells of interest. Commercially-available calibration beads are an indispensable tool when preparing flow cytometers for experiments using fluorescent dyes (e.g. FITC); however, due to the different spectral characteristics of fluorescent proteins versus fluorescent dyes, existing fluorescent dye beads are not suitable for instrument calibration if the cells being analyzed express fluorescent proteins. Therefore, we developed calibration beads labeled with either the red fluorescent protein mCherry or the green fluorescent protein AcGFP, which has spectral properties almost identical to EGFP. Beads with a very low size deviation (CV 2.5–3%) were used to create distinct fluorescent bead populations by covalently linking specific amounts of the respective fluorescent proteins. The low size deviation of the beads, in conjunction with a very controlled labeling method, allowed us to create six bead populations with distinct fluorescent intensities for each of the two fluorescent proteins. Here, we show that the fluorescent protein Flow Cytometer Calibration Beads are easy to use and that they perform equally well on a variety of flow cytometer platforms. We also present data showing that the mean fluorescence intensity of the beads and the calculated number of fluorescent proteins on each respective bead population are distinct from each other and in a linear correlation. We also provide supporting data showing the signal stability of the calibration beads under different buffer and fixative conditions, as well as at different flow rates. The data show that these calibration beads are a very useful tool, enabling fast and reliable calibration of flow cytometers prior to analysis of cells expressing the corresponding fluorescent protein.

  6. Dual-recognition detection of Staphylococcus aureus using vancomycin-functionalized magnetic beads as concentration carriers.

    Science.gov (United States)

    Yang, Shijia; Ouyang, Hui; Su, Xiaoxiao; Gao, Hongfei; Kong, Weijun; Wang, Mengyao; Shu, Qi; Fu, Zhifeng

    2016-04-15

    Vancomycin, which has a strong antibacterial effect to Gram-positive bacteria, was adopted as one molecular recognition agent for bacterial detection. Magnetic beads (MBs) were functionalized with this antibiotic to effectively concentrate Staphylococcus aureus (S. aureus). In addition, alkaline phosphatase (ALP)-tagged rabbit immunoglobulin G (ALP-IgG) was used as the second recognition agent to improve the specificity based on the binding between the Fc region of rabbit IgG and protein A in the cell wall of S. aureus. MBs-concentrated sandwich complex of vancomycin/S. aureus/ALP-IgG was formed with a one-step incubation protocol. Then ALP chemiluminescent reaction was triggered by injecting substrate solution to quantitate S. aureus. Based on the sandwich molecular recognition mechanism and MBs concentration, an ultrasensitive, specific and rapid method was developed for S. aureus detection. The linear range for S. aureus detection was 12-1.2 × 10(6)CFU mL(-1), with a very low detection limit of 3.3 CFU mL(-1). The whole detection process could be completed in 75 min. Other Gram-positive bacteria and Gram-negative bacteria, including Escherichia coli, Salmonella, Pseudomonas aeruginosa, Micrococcus luteus, Bacillus cereus and Bacillus subtilis, showed negligible interference to S. aureus detection. This method was successfully used to quantitate S. aureus in lake water, milk, human urine and human saliva with acceptable recoveries ranging from 70.0% to 116.7%. PMID:26606309

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

    OpenAIRE

    Harikrishnan Jayamohan; Gale, Bruce K.; Bj Minson; Lambert, Christopher J.; Neil Gordon; Himanshu J. Sant

    2015-01-01

    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 th...

  8. Motion Analysis Of An Object Onto Fine Plastic Beads Using High-Speed Camera

    Science.gov (United States)

    Sato, Minoru

    2010-07-01

    Fine spherical polystyrene beads (NaRiKa, D20-1406-01, industrial materials of styrene form) are useful for frictionless demonstrations of dynamics and kinematics. Sawamoto et al. have developed the method of demonstrations using the plastic beads onto a glass board. These fine beads (the average of the diameter is 280 μm and the standard deviation of the diameter is 56 μm) function as ball bearings to reduce the friction between a moving object, glass Petri dish, and the surface of the glass board. The beads that are charged stick onto the glass board by static electricity, and arrange themselves at intervals. The movement characteristic of a Petri dish that moves on the fine polystyrene beads that adhere onto the glass board is shown by video analysis using a USB camera and a high-speed camera (CASIO, EX-F1). The movement of the Petri dish on the fine polystyrene beads onto the glass board is good linearity, but the friction of the beads is not too small. The high-speed video showed that only a small number of beads behind the bottom of the Petri dish supported the Petri dish. The number of the beads that supported the Petri dish that caused the friction is about 0.14.

  9. Preparation of uniform-sized agarose beads by microporous membrane emulsification technique.

    Science.gov (United States)

    Zhou, Qing-Zhu; Wang, Lian-Yan; Ma, Guang-Hui; Su, Zhi-Guo

    2007-07-01

    Uniform-sized agarose beads were prepared by membrane emulsification technique in this study. Agarose was dissolved in boiling water (containing 0.9% sodium chloride) and used as water phase. A mixture of liquid paraffin and petroleum ether containing 4 wt% of hexaglycerin penta ester (PO-500) emulsifier was used as oil phase. At 55 degrees C, the water phase permeated through uniform pores of microporous membrane into the oil phase by a pressure of nitrogen gas to form uniform W/O emulsion. Then the emulsion was cooled down to room temperature under gentle agitation to form gel beads. The effect of oil phase, emulsifier, especially temperature on the uniformity of the beads were investigated and interpreted from interfacial tension between water phase and oil phase. Under optimized condition, the coefficient variation (C.V.) showing the size distribution of the beads was under 15%. This was the first report to prepare uniform agarose beads by membrane emulsification, and to investigate the effect of temperature on the size distribution of the droplets and beads. The beads with different size can be prepared by using membranes with different pore size, and the result showed that there was a linear relationship between the average diameter of beads and pore size of the membranes; beads with diameter from 15 to 60 microm were able to obtain in this study. PMID:17362974

  10. Alginate-konjac glucomannan-chitosan beads as controlled release matrix.

    Science.gov (United States)

    Wang, Kang; He, Zhimin

    2002-09-01

    Controlled release beads were prepared by using alginate (ALG), konjac glucomannan (KGM) and chitosan (CHI). Bovine serum albumin and insulin were used as model proteins for in vitro assessments. It was observed that KGM could be contained within beads, and faintness hydrogen binding and electrostatic interaction exist between ALG and KGM by infrared spectra. Clear dents were found on the surface of beads using KGM by scanning electron microscopy. Use of KGM could help increase the payload of drug. After beads were treated by 0.1 N HCl for 4 h and put into pH 7.4 buffers, protein was released from ALG-CHI beads within 1 h, while it was lost from ALG-KGM-CHI beads for 3 h. However, the leaking of protein from ALG-KGM-CHI beads was also increased in 0.1 N HCl solution. Concentration of gelling ion had great effect on release rate and gel structure. Studies of water of hydration had shown that swelling of ALG-KGM-CHI beads was higher than that of ALG-CHI beads in acidic solution, but the opposite result was obtained in alkali solution. The result indicated that the diffusion of protein was related to the viscosity and swelling properties of KGM. PMID:12204571

  11. Study of synthesis and characterization of curcumin-polyacrylonitrile composite beads for extraction of uranium

    International Nuclear Information System (INIS)

    Curcumin is a yellow coloured compound present in turmeric and accounts for only about 3 to 5 % of its total constituents. Curcumin is an important molecule known for its medicinal and several other usages. It also forms complex with uranyl ions. Curcumin-loaded microporous polyacrylonitrile (PAN) beads were synthesized for extraction of uranium from aqueous waste. PAN was synthesized by radiation induced polymerization of acrylonitrile monomer in aqueous medium. The synthesized PAN was used to make the microporous PAN-Curcumin composite beads. The synthesized beads were evaluated, for their ability to extract uranium from aqueous solution at different temperatures and pH values. The kinetics measurement showed that about 100 minutes of equilibration time was enough to extract saturation amount of uranium from aqueous solution. The polymeric beads exhibited optimum extraction at room temperature and at neutral or near neutral pH conditions. The uranyl ion uptake capacity of the polymeric beads was found to be significant, and it depends upon the loading of curcumin in the beads. The loaded uranium could also be leached out from the beads, by treating with dilute acids. Further, the presence of uranium in the loaded beads was ascertained by FT-IR spectroscopy, while surface morphology of the beads was characterized by SEM technique. (author)

  12. "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

    separator with arrays of soft magnetic elements. The soft magnetic elements placed on both sides of the channel are magnetized by a relatively weak applied external magnetic field ( 21 mT) and provide magnetic field gradients attracting magnetic beads. Flows with two differently functionalized magnetic...... beads and a separating barrier flow are introduced simultaneously at the two channel sides and the centre of the microfluidic channel, respectively. On-chip experiments with fluorescence labeled beads demonstrate that the two types of beads are captured at each of the channel sidewalls. On...

  13. Modulating insulin-release profile from pH/thermosensitive polymeric beads through polymer molecular weight.

    Science.gov (United States)

    Ramkissoon-Ganorkar, C; Liu, F; Baudys, M; Kim, S W

    1999-06-01

    Stimuli-sensitive statistical terpolymers of N-isopropylacrylamide (NIPAAm) (temperature-sensitive), butyl methacrylate (BMA) and acrylic acid (AA) (pH-sensitive) of various molecular weight (MW) with NIPAAm/BMA/AA feed mol ratio of 85/5/10 were used to modulate release of insulin, a model protein drug, from pH/thermosensitive polymeric beads. Protein drug loading from an aqueous medium into the beads was achieved by preparing a 7 or 10% (w/v) polymer solution with 0.2% (w/v) insulin at low pH and below the lower critical solution temperature (LCST) of the polymer (pH 2.0 and 4 degrees C), and then dropping the solution into an oil bath above the LCST of the solution (35 degrees C). This loading procedure maintained protein stability while achieving high loading efficiency, between 90 and 95% in the beads. Insulin-release studies from beads prepared from terpolymers of the same composition but increasing MW were performed at pH 2.0 and 7.4, at 37 degrees C. It was observed that there was negligible loss of insulin at pH 2.0 from the beads, indicating no burst effect. At pH 7.4, insulin release was seen from all the beads and the release rate was a function of the MW of the polymer. The low MW polymeric beads eroded, dissolved and released most of the insulin within 2 h at pH 7.4 and 37 degrees C, the intermediate MW polymeric beads swelled slightly, dissolved and released most of the insulin within 4 h, whereas the high MW polymeric beads swelled slowly and gradually released the loaded insulin over a period of 8 h. Thus, the release of protein from the low MW polymeric beads is controlled by the rate of dissolution of the polymer, whereas the release from the high MW polymeric beads is controlled by swelling of the beads and drug diffusion. Studies using fluorescein-labeled insulin revealed that insulin was uniformly distributed in the beads regardless of polymer MW. The loaded and released insulin were fully bioactive. Based on the described results, the low MW

  14. Microscopic Examination of Chitosan Polyphosphate Beads with Entrapped Spores of the Biocontrol Agent, Streptomyces melanosporofaciens EF-76

    Science.gov (United States)

    Jobin, Guy; Grondin, Gilles; Couture, Geneviève; Beaulieu, Carole

    2005-04-01

    Spores of the biocontrol agent, Streptomyces melanosporofaciens EF-76, were entrapped by complex coacervation in beads composed of a macromolecular complex (MC) of chitosan and polyphosphate. A proportion of spores entrapped in beads survived the entrapment procedure as shown by treating spores from chitosan beads with a dye allowing the differentiation of live and dead cells. The spore-loaded chitosan beads could be digested by a chitosanase, suggesting that, once introduced in soil, the beads would be degraded to release the biocontrol agent. Spore-loaded beads were examined by optical and scanning electron microscopy because the release of the biological agent depends on the spore distribution in the chitosan beads. The microscopic examination revealed that the beads had a porous surface and contained a network of inner microfibrils. Spores were entrapped in both the chitosan microfibrils and the bead lacuna.

  15. A Porous Simulation Experiment of Protozoa Movement with Glass Bead

    Institute of Scientific and Technical Information of China (English)

    LIU Hai-ming; ZHAO Xiao-rong; LI Gui-tong; LIN Qi-mei

    2003-01-01

    Protozoa can move due to their flagella, cilia or pseudopodia, and play an important role in the transformation and cycling of matter and energy in ecosystems. In this study, the glass beads with the diameters of 1.0, 0.5, 0.25 and 0.1 mm were used to simulate soil pores of 0. 292 - 0. 258, 0. 155 - 0.116, 0. 056- 0. 040 and 0. 028 - 0.020 mm respectively. Three typical soil protozoa of Bodo edax, Colpoda cucullus and Amoeba proteus were examined for the relation of their movement to pores. It was found that the smallest protozoan of Bodo edax could be leached through all the pores. However, no more than 26% of the added protozoan was leached out of the column. The leached protozoa were decreased with the pore sizes and leaching duration. The bigger one of Colpoda cucullus was moved out from the column filled with the glass beads of >0.5 mm in diameter. Less than about 15 % of the added protozoa were leached out of the column. The biggest one of Amoeba proteus could not leached out from any of the pores. It is evident that most of the protozoa remained in the column due to their occupation of the pores.

  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. 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

  18. Viscosity of dilute suspensions of rigid bead arrays at low shear: accounting for the variation in hydrodynamic stress over the bead surfaces.

    Science.gov (United States)

    Allison, Stuart A; Pei, Hongxia

    2009-06-11

    In this work, we examine the viscosity of a dilute suspension of irregularly shaped particles at low shear. A particle is modeled as a rigid array of nonoverlapping beads of variable size and geometry. Starting from a boundary element formalism, approximate account is taken of the variation in hydrodynamic stress over the surface of the individual beads. For a touching dimer of two identical beads, the predicted viscosity is lower than the exact value by 5.2%. The methodology is then applied to several other model systems including tetramers of variable conformation and linear strings of touching beads. An analysis is also carried out of the viscosity and translational diffusion of several dilute amino acids and diglycine in water. It is concluded that continuum hydrodynamic modeling with stick boundary conditions is unable to account for the experimental viscosity and diffusion data simultaneously. A model intermediate between "stick" and "slip" could possibly reconcile theory and experiment. PMID:19453112

  19. Conscientisation in Castalia: A Freirean Reading of Hermann Hesse's "The Glass Bead Game"

    Science.gov (United States)

    Roberts, Peter

    2007-01-01

    This paper considers Hermann Hesse's novel, "The Glass Bead Game," in the light of Paulo Freire's educational philosophy. "The Glass Bead Game" is set in Castalia, a "pedagogical province" of the 23rd century. It is argued that the central character in the book, Joseph Knecht, undergoes a complex process of conscientisation. Knecht develops an…

  20. 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

    2001-01-01

    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 preferenti

  1. An adaptive algorithm for tracking 3D bead displacements: application in biological experiments

    International Nuclear Information System (INIS)

    This paper presents a feature-vector-based relaxation method (FVRM) to track bead displacements within a three-dimensional (3D) volume. The FVRM merges the feature vector method, a technique used in tracking bead displacements in biological gels, with the relaxation method, an algorithm employed successfully in tracking bead pairs in fluids. More specifically, the FVRM evaluates the probability of a bead pairing event based on the quasi-rigidity condition between the feature vectors of a bead and its candidate positions within a searching domain. Computational efficiency is improved via the introduction of an adaptive searching domain size and mismatches are reduced via a two-directional matching strategy. The algorithm is validated using simulated 3D bead displacements caused by a force dipole within a linear elastic gel. Results demonstrate a consistently high recovery ratio (above 98%) and low mismatch ratio (below 0.1%) for tracking parameter (mean bead distance/maximum bead displacement) greater than 0.73. (paper)

  2. 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...... for biomolecular recognition. (C) 2011 American Institute of Physics. [doi:10.1063/1.3554374]...

  3. 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. PMID:9724569

  4. Glycopolymeric gel stabilized N-succinyl chitosan beads for controlled doxorubicin delivery.

    Science.gov (United States)

    Ajish, Juby K; Ajish Kumar, K S; Chattopadhyay, S; Kumar, Manmohan

    2016-06-25

    Here we report the synthesis and study of N-succinyl chitosan based hydrogel beads, stabilized with glycopolymeric network (NSC/Glc-gel) for application in anticancer drug delivery of doxorubicin (DOX). The bio-recognition of lectins by NSC/Glc-gel bead was also studied by UV-vis spectrophotometry. The beads were characterized using FT-IR, SEM and Thermogravimetric analysis. The extent of DOX loading was proportional to the degree of succinylation and the swelling kinetics of the beads showed pH dependency. The beads exhibited sustained release of DOX over a period of more than 15 days in an acidic pH, mimicking the microenvironment of tumor cells, and even lesser release at physiological pH. Release exponent 'n' derived from Korsmeyer-Peppas model implied that NSC88/Glc-gel (88% succinylation of chitosan) beads followed fickian diffusion controlled release mechanism whereas NSC75/Glc-gel (75% succinylation of chitosan) beads follow zero order release profile. The synthesized beads also displayed specificity to lectin Concanavalin A. PMID:27083798

  5. EXPERIMENTAL TESTING OF DRAW-BEAD RESTRAINING FORCE IN SHEET METAL FORMING

    Institute of Scientific and Technical Information of China (English)

    J.H. Yang; J. Chen; D.N. He; X. Y. Ruan

    2003-01-01

    Due to complexities of draw-bead restraining force calculated according to theory anddepending on sheet metal forming properties experiment testing system, a simplifiedmethod to calculate draw-bead restraining force is put forward by experimental methodin cup-shaped drawing process. The experimental results were compared with numer-ical results and proved agreement. It shows the method is effective.

  6. Opportunities for bead-based multiplex assays in veterinary diagnostic laboratories

    Science.gov (United States)

    Bead based multiplex assays (BBMA) also referred to as Luminex, MultiAnalyte Profiling or cytometric bead array (CBA) assays, are applicable for high throughput, simultaneous detection of multiple analytes in solution (from several, up to 50-500 analytes within a single, small sample volume). Curren...

  7. Capture of DNA in microfluidic channel using magnetic beads: increasing capture efficiency with integrated microfluidic mixer

    DEFF Research Database (Denmark)

    Lund-Olesen, Torsten; Dufva, Hans Martin; Hansen, Mikkel Fougt

    2007-01-01

    We have studied the hybridization of target DNA in solution with probe DNA on magnetic beads immobilized on the channel sidewalls in a magnetic bead separator. The hybridization is carried out under a liquid flow and is diffusion limited. Two systems are compared: one with a straight microfluidic...... place on the surface in a microfluidic system....

  8. OBT analysis method using polyethylene beads for limited quantities of animal tissue

    International Nuclear Information System (INIS)

    This study presents a polyethylene beads method for OBT determination in animal tissues and animal products for cases where the amount of water recovered by combustion is limited by sample size or quantity. In the method, the amount of water recovered after combustion is enhanced by adding tritium-free polyethylene beads to the sample prior to combustion in an oxygen bomb. The method reduces process time by allowing the combustion water to be easily collected with a pipette. Sufficient water recovery was achieved using the polyethylene beads method when 2 g of dry animal tissue or animal product were combusted with 2 g of polyethylene beads. Correction factors, which account for the dilution due to the combustion water of the beads, are provided for beef, chicken, pork, fish and clams, as well as egg, milk and cheese. The method was tested by comparing its OBT results with those of the conventional method using animal samples collected on the Chalk River Laboratories (CRL) site. The results determined that the polyethylene beads method added no more than 25% uncertainty when appropriate correction factors are used. - Highlights: • Polyethylene beads method for OBT determination in animal tissues and animal products were determined. • The method reduces process time. • The polyethylene beads method added no more than 25% uncertainty when appropriate correction factors are used

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

    Science.gov (United States)

    Smistrup, K; Kjeldsen, B G; Reimers, J L; Dufva, M; Petersen, J; Hansen, M F

    2005-11-01

    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 separator with arrays of soft magnetic elements. The soft magnetic elements placed on both sides of the channel are magnetized by a relatively weak applied external magnetic field (21 mT) and provide magnetic field gradients attracting magnetic beads. Flows with two differently functionalized magnetic beads and a separating barrier flow are introduced simultaneously at the two channel sides and the centre of the microfluidic channel, respectively. On-chip experiments with fluorescence labeled beads demonstrate that the two types of beads are captured at each of the channel sidewalls. On-chip hybridization experiments show that the microfluidic systems can be functionalized with two sets of beads carrying different probes that selectively recognize a single base pair mismatch in target DNA. By switching the places of the two types of beads it is shown that the microsystem can be cleaned and functionalized repeatedly with different beads with no cross-talk between experiments. PMID:16234958

  10. 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

    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...

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

    International Nuclear Information System (INIS)

    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-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.

  12. Skyrmions confined as beads on a vortex ring

    Science.gov (United States)

    Gudnason, Sven Bjarke; Nitta, Muneto

    2016-07-01

    A very simple, quadratic potential is used to construct vortex strings in a generalized Skyrme model and an additional quadratic potential is used to embed sine-Gordon-type halfkinks onto the string worldline, yielding half-Skyrmions on a string. The strings are furthermore compactified onto a circle and the halfkinks are forced to appear in pairs; in particular 2 B halfkinks (half-Skyrmions) will appear as beads on a ring with B being the number of times the host vortex is twisted and also the baryon number (Skyrmion number) from the bulk point of view. Finally, we construct an effective field theory on the torus, describing the kinks living on the vortex rings.

  13. Skyrmions confined as beads on a vortex ring

    CERN Document Server

    Gudnason, Sven Bjarke

    2016-01-01

    A very simple, quadratic potential is used to construct vortex strings in a generalized Skyrme model and an additional quadratic potential is used to embed sine-Gordon-type halfkinks onto the string worldline, yielding half-Skyrmions on a string. The strings are furthermore compactified onto a circle and the halfkinks are forced to appear in pairs; in particular 2B halfkinks (half-Skyrmions) will appear as beads on a ring with B being the number of times the host vortex is twisted and also the baryon number (Skyrmion number) from the bulk point of view. Finally, we construct an effective field theory on the torus, describing the kinks living on the vortex rings.

  14. Solar Limb Darkening Function from Baily's Beads Observations

    CERN Document Server

    Raponi, Andrea

    2011-01-01

    We introduce a method to measure with high resolution the solar diameter from the ground, through the eclipse observations by reconsidering the definition of the solar edge. The outer part of the Limb Darkening Function (LDF) is recovered using the luminosity evolution of a Baily's Bead and the profile of the lunar limb available from the Kaguya satellite. The method proposed is applied for the videos of the eclipse in January, 15, 2010 recorded by Richard Nugent in Uganda and Andreas Tegtmeier in India. The result shows light from solar limb detected at least 0.65 arcsec beyond the LDF inflection point, and this fact may suggest to reconsider the evaluations of the historical eclipses made with naked eye.

  15. Development and Evaluation of Dual Cross-Linked Pulsatile Beads for Chronotherapy of Rheumatoid Arthritis

    Directory of Open Access Journals (Sweden)

    Abanesh kumar Bansal

    2013-01-01

    Full Text Available In the present investigation, pulsatile release beads were prepared by ionic gelation technique. Lornoxicam dual cross-linked beads were prepared by dropping dispersed phase of lornoxicam, pectin, and sodium alginate into the dispersion phase of different concentrations of calcium chloride solution followed by aluminium chloride solution. The formulated beads were further coated by Eudragit L & S 100 in the ratio 1 : 2 w/w in order to achieve desired lag time. In vitro release study showed lag time of 5–8 h before release of lornoxicam from the formulated beads. Thus, formulated dual cross-linked beads when administered at bed time may release lornoxicam when needed most for chronotherapeutics of early morning rheumatoid arthritis attacks in chronic patients.

  16. Preparation and characterization of crosslinked alginate-CMC beads for controlled release of nitrate salt

    International Nuclear Information System (INIS)

    Carboxymethyl cellulose (CMC)/sodium alginate (SA) hydrogel beads were successfully prepared by Ca2+ ions crosslinking followed by gamma irradiation. The factors affecting beads formation are the composition of SA in the blend and concentration of calcium chloride as a crosslinking agent. The results indicated that the addition of CMC to SA increases the swelling (%) upto (1:3) (CMC:SA) ratio. The effect of different irradiation doses (2.5, 5, and 10 kGy) on swelling (%) was studied. At low doses, swelling (%) decreases upto 5 kGy then starts to increase at 10 kGy. The degree of the swelling (%) and release (%) of ammonium nitrate salt from beads were investigated under different pH (1.2, 5 and 7). The beads were characterized by FTIR, SEM and TGA to investigate molecular structure, morphology and thermal stability of beads. (author)

  17. The Use of Index-Matched Beads in Optical Particle Counters.

    Science.gov (United States)

    Hu, Zhishang; Ripple, Dean C

    2014-01-01

    In this paper, we demonstrate the use of 2-pyridinemethanol (2P) aqueous solutions as a refractive index matching liquid. The high refractive index and low viscosity of 2P-water mixtures enables refractive index matching of beads that cannot be index matched with glycerol-water or sucrose-water solutions, such as silica beads that have the refractive index of bulk fused silica or of polymethylmethacrylate beads. Suspensions of beads in a nearly index-matching liquid are a useful tool to understand the response of particle counting instruments to particles of low optical contrast, such as aggregated protein particles. Data from flow imaging and light obscuration instruments are presented for bead diameters ranging from 6 µm to 69 µm, in a matrix liquid spanning the point of matched refractive index. PMID:26601049

  18. Polymerized serum albumin beads for use as slow-release adjuvants

    International Nuclear Information System (INIS)

    Experimental vaccines have been made by covalently bonding virus particles into polymerized rabbit serum albumin beads. Using Nodamura virus as a model antigen, these model vaccines induced specific humoral antibody production, comparable with that achieved using Freund's adjuvants. Virus specific antibodies were also induced when Nodamura virus was covalently attached to the bead surface using different crosslinkers. However, when poliovirus type 2 (Sabin strain) was polymerized into beads, the levels of neutralizing antibodies were insignificant compared with control aqueous vaccines. The synthetic immunostimulator, muramyl dipeptide, was included with bead vaccines in an attempt to potentiate the immune response. Immunostimulation is achieved by a slow release of antigen coinciding with the gradual breakdown of bead structure. Methods used include radio-iodination and radioimmunoassay. 65 figs., 6 tabs., 173 refs

  19. 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.

  20. Domain Walls on Singularities

    CERN Document Server

    Halyo, Edi

    2009-01-01

    We describe domain walls that live on $A_2$ and $A_3$ singularities. The walls are BPS if the singularity is resolved and non--BPS if it is deformed and fibered. We show that these domain walls may interpolate between vacua that support monopoles and/or vortices.

  1. 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.

  2. REVIEW: CHITOSAN BASED HYDROGEL POLYMERIC BEADS – AS DRUG DELIVERY SYSTEM

    Directory of Open Access Journals (Sweden)

    Manjusha Rani

    2010-11-01

    Full Text Available Chitosan obtained by alkaline deacetylation of chitin is a non-toxic, biocompatible, and biodegradable natural polymer. Chitosan-based hydrogel polymeric beads have been extensively studied as micro- or nano-particulate carriers in the pharmaceutical and medical fields, where they have shown promise for drug delivery as a result of their controlled and sustained release properties, as well as biocompatibility with tissue and cells. To introduce desired properties and enlarge the scope of the potential applications of chitosan, graft copolymerization with natural or synthetic polymers on it has been carried out, and also, various chitosan derivatives have been utilized to form beads. The desired kinetics, duration, and rate of drug release up to therapeutical level from polymeric beads are limited by specific conditions such as beads material and their composition, bead preparation method, amount of drug loading, drug solubility, and drug polymer interaction. The present review summarizes most of the available reports about compositional and structural effects of chitosan-based hydrogel polymeric beads on swelling, drug loading, and releasing properties. From the studies reviewed it is concluded that chitosan-based hydrogel polymeric beads are promising drug delivery systems.

  3. Molecularly imprinted porous beads for the selective removal of copper ions.

    Science.gov (United States)

    Younis, M Rizwan; Bajwa, Sadia Z; Lieberzeit, Peter A; Khan, Waheed S; Mujahid, Adnan; Ihsan, Ayesha; Rehman, Asma

    2016-02-01

    In the present work, novel molecularly imprinted polymer porous beads for the selective separation of copper ions have been synthesized by combining two material-structuring techniques, namely, molecular imprinting and oil-in-water-in-oil emulsion polymerization. This method produces monodisperse spherical beads with an average diameter of ∼2-3 mm, in contrast to adsorbents produced in the traditional way of grinding and sieving. Field-emission scanning electron microscopy indicates that the beads are porous in nature with interconnected pores of about 25-50 μm. Brunner-Emmett-Teller analysis shows that the ion-imprinted beads possess a high surface area (8.05 m(2) /g), and the total pore volume is determined to be 0.00823 cm(3) /g. As a result of the highly porous nature and ion-imprinting, the beads exhibit a superior adsorption capacity (84 mg/g) towards copper than the non-imprinted material (22 mg/g). Furthermore, selectivity studies indicate that imprinted beads show splendid recognizing ability, that is, nearly fourfold greater selective binding for Cu(2+) in comparison to the other bivalent ions such as Mn(2+) , Ni(2+) , Co(2+) , and Ca(2+) . The imprinted composite beads prepared in this study possess uniform porous morphology and may open up new possibilities for the selective removal of copper ions from waste water/contaminated matrices. PMID:26632078

  4. 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. PMID:21809830

  5. Pharmaceutical acrylic beads obtained by suspension polymerization containing cellulose nanowhiskers as excipient for drug delivery.

    Science.gov (United States)

    Villanova, J C O; Ayres, E; Carvalho, S M; Patrício, P S; Pereira, F V; Oréfice, R L

    2011-03-18

    Direct compression is one of the most popular techniques to prepare tablets but only a few commercial excipients are well adapted for this process into controlled release formulations. In the last years, the introduction of new materials for drug delivery matrix tablets has become more important. This paper evaluated the physicochemical and flow properties of new polymeric excipient of ethyl acrylate, methyl methacrylate and butyl metacrylate, synthesized by suspension polymerization using cellulose nanowhiskers as co-stabilizer, to be used as direct compression for modified release tablets. Infrared spectroscopy (FTIR) confirmed the success of the copolymerization reaction. Scanning electron microscopy (SEM) showed that excipient was obtained how spherical beads. Thermal properties of the beads were characterized by thermogravimetric (TG) analysis. Particle size analysis of the beads with cellulose nanowhiskers (CNWB) indicated that the presence of the nanowhiskers led to a reduction of particle size and to a narrower size distribution. In vitro test showed that the nanowhiskers and beads produced are nontoxic. Parameters such as Hausner ratio, Carr's index and cotangent of angle α were employed to characterize the flow properties of CNWB beads. Furthermore, the beads are used to produce tablets by direct compression contained propranolol hydrochloride as model drug. Dissolution tests performed suggested that beads could be used as excipient in matrix tablets with a potential use in drug controlled release. PMID:21241802

  6. Preparation of Silk Sericin/Lignin Blend Beads for the Removal of Hexavalent Chromium Ions.

    Science.gov (United States)

    Kwak, Hyo Won; Shin, Munju; Yun, Haesung; Lee, Ki Hoon

    2016-01-01

    In the present study, novel adsorbents having high adsorption capability and reusability were prepared using agricultural by-products: silk sericin and lignin. Silk sericin and lignin blend beads were successfully prepared using simple coagulation methods for the removal of hexavalent chromium (Cr(VI)) from aqueous solution. A 1 M lithium chloride (LiCl)/dimethyl sulfoxide (DMSO) solvent system successfully dissolved both sericin and lignin and had sufficient viscosity for bead preparation. Compared to the conventional sericin bead adsorbent, sericin/lignin blend beads showed higher Cr(VI) adsorption capacity. The amount of lignin added to the adsorbent greatly affected the adsorption capacity of the beads, and a 50:50 sericin/lignin blend ratio was optimal. Adsorption behavior followed the Freundlich isotherm, which means the adsorption of Cr(VI) occurred on the heterogeneous surface. Cr(VI) adsorption capability increased with temperature because of thermodynamic-kinetic effects. In addition, over 90% of Cr(VI) ions were recovered from the Cr(VI) adsorbed sericin/lignin beads in a 1 M NaOH solution. The adsorption-desorption recycling process was stable for more than seven cycles, and the recycling efficiency was 82%. It is expected that the sericin/lignin beads could be successfully applied in wastewater remediation especially for hazardous Cr(VI) ions in industrial wastewater. PMID:27598142

  7. The configurations of a FENE bead-spring chain in transient rheological flows and in a turbulent flow

    Science.gov (United States)

    Massah, Heshmat; Kontomaris, Kostas; Schowalter, William R.; Hanratty, Thomas J.

    1993-04-01

    The changes in the configuration of a FENE bead-spring chain in a direct numerical simulation of turbulent channel flow and in some simple rheological flows are examined. Unraveling occurs both in uniaxial and shear flows, but the uniaxial flow is more effective. A vortex with a large rotation rate perpendicular to the principal strain of a uniaxial flow has only a minor retarding effect while a small rotation rate delays the unraveling substantially. In a turbulent flow, the chain unravels the most in the viscous sublayer, to about 90% of its fully extended length. It aligns at a 7° angle with the direction of mean flow. In the buffer zone, it unravels and coils up and takes different orientations at different times. Outside the wall region, the chain assumes a coiled configuration. The unraveling of the chain strongly depends on the relaxation time of the chain normalized with the wall shear rate, λ+. A value of λ+=10 exhibits strong unraveling while very weak unraveling is observed below λ+=1.

  8. Biological deterioration of alginate beads containing immobilized microalgae and bacteria during tertiary wastewater treatment.

    Science.gov (United States)

    Cruz, Ivonne; Bashan, Yoav; Hernàndez-Carmona, Gustavo; de-Bashan, Luz E

    2013-11-01

    Secondary treatment of municipal wastewater affects the mechanical stability of polymer Ca-alginate beads containing the microalgae Chlorella vulgaris that are jointly immobilized with Azospirillum brasilense as treating agents whose presence do not affect bead stability. Nine strains of potential alginate-degrading bacteria were isolated from wastewater and identified, based on their nearly complete 16S rDNA sequence. Still, their population was relatively low. Attempts to enhance the strength of the beads, using different concentrations of alginate and CaCl2 or addition of either of three polymers (polyvinylpyrrolidone, polyvinyl alcohol, carboxymethylcellulose), CaCO3, or SrCl2, failed. Beads lost their mechanical strength after 24 h of incubation but not the integrity of their shape for at least 96 h, a fact that sustained successful tertiary wastewater treatment for 48 h. In small bioreactors, removal of phosphorus was low under sterile conditions but high in unsterile wastewater. Alginate beads did not absorb PO4 (-3) in sterile wastewater, but in natural wastewater, they contained PO4 (-3). Consequently, PO4 (-3) content declined in the wastewater. A supplement of 10 % beads (w/v) was significantly more efficient in removing nutrients than 4 %, especially in a jointly immobilized treatment where >90 % of PO4 (-3) and >50 % ammonium were removed. Tertiary wastewater treatment in 25-L triangular, airlift, autotrophic bioreactors showed, as in small bioreactors, very similar nutrient removal patterns, decline in bead strength phenomena, and increase in total bacteria during the wastewater treatment only in the presence of the immobilized treatment agents. This study demonstrates that partial biological degradation of alginate beads occurred during tertiary wastewater treatment, but the beads survive long enough to permit efficient nutrient removal. PMID:23354446

  9. Effects of sample delivery on analyte capture in porous bead sensors.

    Science.gov (United States)

    Chou, Jie; Li, Luanyi E; Kulla, Eliona; Christodoulides, Nicolaos; Floriano, Pierre N; McDevitt, John T

    2012-12-21

    Sample delivery is a crucial aspect of point-of-care applications where sample volumes need to be low and assay times short, while providing high analytical and clinical sensitivity. In this paper, we explore the influence of the factors surrounding sample delivery on analyte capture in an immunoassay-based sensor array manifold of porous beads resting in individual wells. We model using computational fluid dynamics and a flow-through device containing beads sensitized specifically to C-reactive protein (CRP) to explore the effects of volume of sample, rate of sample delivery, and use of recirculation vs. unilateral delivery on the effectiveness of the capture of CRP on and within the porous bead sensor. Rate of sample delivery lends to the development of a time-dependent, shrinking depletion region around the bead exterior. Our findings reveal that at significantly high rates of delivery, unique to porous bead substrates, capture at the rim of the bead is reaction-limited, while capture in the interior of the bead is transport-limited. While the fluorescence signal results from the aggregate of captured material throughout the bead, multiple kinetic regimes exist within the bead. Further, under constant pressure conditions dictated by the array architecture, we reveal the existence of an optimal flow rate that generates the highest signal, under point-of-care constraints of limited-volume and limited-time. When high sensitivity is needed, recirculation can be implemented to overcome the analyte capture limitations due to volume and time constraints. Computational simulations agree with experimental results performed under similar conditions. PMID:23117481

  10. Cadmium removal out of human plasma using ion-imprinted beads in a magnetic column

    Energy Technology Data Exchange (ETDEWEB)

    Candan, Nilguen; Tuezmen, Nalan [Department of Chemistry, Dokuzeyluel University, Izmir (Turkey); Andac, Muge [Department of Chemistry, Biochemistry Division, Hacettepe University, Ankara (Turkey); Andac, Cenk A. [Department of Chemistry, Dicle University, Diyarbakir (Turkey); Say, Ridvan [Department of Chemistry, Anadolu University, Eskisehir (Turkey); Denizli, Adil [Department of Chemistry, Biochemistry Division, Hacettepe University, Ankara (Turkey)], E-mail: denizli@hacettepe.edu.tr

    2009-01-01

    The aim of this study is to utilize ion-imprinted magnetic beads in the selective removal of Cd{sup 2+} ions out of human plasma overdosed with Cd{sup 2+} ions. The Cd{sup 2+} imprinted magnetic poly(HEMA-MAC) (mPHEMAC-Cd{sup 2+}) beads were produced by suspension polymerization in the presence of magnetite Fe{sub 3}O{sub 4} in a nano-powder form. The template Cd{sup 2+} ions could be reversibly detached from the matrix to form mPHEMAC-Cd{sup 2+} beads using 0.1 M thiourea solution. The specific surface area of the mPHEMAC-Cd{sup 2+} beads was found to be 24.7 m{sup 2}/g. The MAC and Fe{sub 3}O{sub 4} contents of the mPHEMAC-Cd{sup 2+} beads were found to be 41.8 {mu}mol/g polymer and 8.2% on the average. The Cd{sup 2+} adsorption capacity of mPHEMAC-Cd{sup 2+} columns decreased drastically from 48.8 {mu}mol/g to 20.0 {mu}mol/g as the flow rate is increased from 0.50 ml/min to 3.0 ml/min. The maximum adsorption capacity of the mPHEMAC-Cd{sup 2+} beads was determined to be 48.8 {mu}mol Cd{sup 2+}/g on the average. The relative selectivity coefficients of the mPHEMAC beads for Cd{sup 2+}/Pb{sup 2+} and Cd{sup 2+}/Zn{sup 2+} were 22.6 and 160.7 times greater than those of the non-imprinted magnetic PHEMAC (mPHEMAC) beads, respectively. The mPHEMAC-Cd{sup 2+} beads are reusable for many times with no significant decrease in their adsorption capacities.

  11. Cadmium removal out of human plasma using ion-imprinted beads in a magnetic column

    International Nuclear Information System (INIS)

    The aim of this study is to utilize ion-imprinted magnetic beads in the selective removal of Cd2+ ions out of human plasma overdosed with Cd2+ ions. The Cd2+ imprinted magnetic poly(HEMA-MAC) (mPHEMAC-Cd2+) beads were produced by suspension polymerization in the presence of magnetite Fe3O4 in a nano-powder form. The template Cd2+ ions could be reversibly detached from the matrix to form mPHEMAC-Cd2+ beads using 0.1 M thiourea solution. The specific surface area of the mPHEMAC-Cd2+ beads was found to be 24.7 m2/g. The MAC and Fe3O4 contents of the mPHEMAC-Cd2+ beads were found to be 41.8 μmol/g polymer and 8.2% on the average. The Cd2+ adsorption capacity of mPHEMAC-Cd2+ columns decreased drastically from 48.8 μmol/g to 20.0 μmol/g as the flow rate is increased from 0.50 ml/min to 3.0 ml/min. The maximum adsorption capacity of the mPHEMAC-Cd2+ beads was determined to be 48.8 μmol Cd2+/g on the average. The relative selectivity coefficients of the mPHEMAC beads for Cd2+/Pb2+ and Cd2+/Zn2+ were 22.6 and 160.7 times greater than those of the non-imprinted magnetic PHEMAC (mPHEMAC) beads, respectively. The mPHEMAC-Cd2+ beads are reusable for many times with no significant decrease in their adsorption capacities

  12. Release of angiogenic growth factors from cells encapsulated in alginate beads with bioactive glass.

    Science.gov (United States)

    Keshaw, Hussila; Forbes, Alastair; Day, Richard M

    2005-07-01

    Attempts to stimulate therapeutic angiogenesis using gene therapy or delivery of recombinant growth factors, such as vascular endothelial growth factor (VEGF), have failed to demonstrate unequivocal efficacy in human trials. Bioactive glass stimulates fibroblasts to secrete significantly increased amounts of angiogenic growth factors and therefore has a number of potential applications in therapeutic angiogenesis. The aim of this study was to assess whether it is possible to encapsulate specific quantities of bioactive glass and fibroblasts into alginate beads, which will secrete growth factors capable of stimulating angiogenesis. Human fibroblasts (CCD-18Co) were encapsulated in alginate beads with specific quantities of 45S5 bioactive glass and incubated in culture medium (0-17 days). The conditioned medium was collected and assayed for VEGF or used to assess its ability to stimulate angiogenesis by measuring the proliferation of human dermal microvascular endothelial cells. At 17 days the beads were lysed and the amount of VEGF retained by the beads measured. Fibroblasts encapsulated in alginate beads containing 0.01% and 0.1% (w/v) 45S5 bioactive glass particles secreted increased quantities of VEGF compared with cells encapsulated with 0% or 1% (w/v) 45S5 bioactive glass particles. Lysed alginate beads containing 0.01% and 0.1% (w/v) 45S5 bioactive glass contained significantly more VEGF (p<0.01) compared with beads containing no glass particles. Endothelial cell proliferation was significantly increased (p<0.01) by conditioned medium collected from alginate beads containing 0.1% (w/v) 45S5 bioactive glass particles. The results of this study demonstrate that bioactive glass and fibroblasts can be successfully incorporated into alginate beads for use in delivering angiogenic growth factors. With further optimization, this technique offers a novel delivery device for stimulating therapeutic angiogenesis. PMID:15664644

  13. Decolourisation of dyes under electro-Fenton process using Fe alginate gel beads

    International Nuclear Information System (INIS)

    Highlights: ► Catalytic activity of Fe alginate gel beads for the remediation of wastewater was tested. ► New electro-Fenton process for the remediation of polluted wastewater. ► Continuous dye treatment without operational problem with high removal. - Abstract: This study focuses on the application of electro-Fenton technique by use of catalytic activity of Fe alginate gel beads for the remediation of wastewater contaminated with synthetic dyes. The Fe alginate gel beads were evaluated for decolourisation of two typical dyes, Lissamine Green B and Azure B under electro-Fenton process. After characterization of Fe alginate gel beads, the pH effect on the process with Fe alginate beads and a comparative study of the electro-Fenton process with free Fe and Fe alginate bead was done. The results showed that the use of Fe alginate beads increases the efficiency of the process; moreover the developed particles show a physical integrity in a wide range of pH (2–8). Around 98–100% of dye decolourisation was obtained for both dyes by electro-Fenton process in successive batches. Therefore, the process was performed with Fe alginate beads in a bubble continuous reactor. High color removal (87–98%) was attained for both dyes operating at a residence time of 30 min, without operational problems and maintaining particle shapes throughout the oxidation process. Consequently, the stable performance of Fe alginate beads opens promising perspectives for fast and economical treatment of wastewater polluted by dyes or similar organic contaminants.

  14. Bead-on-plate weldability of Al 5052 alloy using a disk laser

    OpenAIRE

    J.-K. Kim; H.-S. Lim; J.-H. Cho; C.-H. Kim

    2008-01-01

    Purpose: The paper presents the effect of the laser welding parameters of the laser focal position and beam angle on the weldability of an Al 5052 thick plate using a 4kW disk laser.Design/methodology/approach: Bead-on-plate welding was conducted on a 10mm-thick Al 5052 plate. Aspects of the bead, including the bead surface and cross sections, were evaluated with various laser welding parameters. The porosity formation was also examined in an X-ray transmission tests.Findings: Altho...

  15. Wax-incorporated Emulsion Gel Beads of Calcium Pectinate for Intragastric Floating Drug Delivery

    OpenAIRE

    Sriamornsak, Pornsak; Asavapichayont, Panida; Nunthanid, Jurairat; Luangtana-anan, Manee; Limmatvapirat, Sontaya; Piriyaprasarth, Suchada

    2008-01-01

    The purpose of this study was to prepare wax-incorporated pectin-based emulsion gel beads using a modified emulsion-gelation method. The waxes in pectin–olive oil mixtures containing a model drug, metronidazole, were hot-melted, homogenized and then extruded into calcium chloride solution. The beads formed were separated, washed with distilled water and dried for 12 h. The influence of various types and amounts of wax on floating and drug release behavior of emulsion gel beads of calcium pect...

  16. Morphology and buoyancy of oil-entrapped calcium pectinate gel beads

    OpenAIRE

    Sriamornsak, Pornsak; Thirawong, Nartaya; Puttipipatkhachorn, Satit

    2004-01-01

    A new emulsion-gelation method to prepare oil-entrapped calcium pectinate gel (CaPG) beads capable of floating in the gastric condition was designed and tested. The gel beads containing edible oil were prepared by either being gently mixed or homogenized an oil phase and a water phase containing pectin, and then extruded into calcium chloride solution with gentle agitation at room temperature. The gel beads formed were then separated, washed with distilled water, and dried at 37°C for 12 hour...

  17. Effect of welding current and speed on occurrence of humping bead in high-speed GMAW

    Institute of Scientific and Technical Information of China (English)

    Chen Ji; Wu Chuansong

    2009-01-01

    The developed mathematical model of humping formation mechanism in high-speed gas metal arc welding (GMAW) is used to analyze the effects of welding current and welding speed on the occurrence of humping bead. It considers both the momentum and heat content of backward flowing molten jet inside weld pool. Three-dimensional geometry of weld pool, the spacing between two adjacent humps and hump height along humping weld bead are calculated under different levels of welding current and welding speed. It shows that wire feeding rate, power intensity and the moment of backward flowing molten jet are the major factors on humping bead formation.

  18. Pulsed laser manipulation of an optically trapped bead: Averaging thermal noise and measuring the pulsed force amplitude

    DEFF Research Database (Denmark)

    Lindballe, Thue Bjerring; Kristensen, Martin V. G.; Berg-Sørensen, Kirstine;

    2013-01-01

    An experimental strategy for post-eliminating thermal noise on position measurements of optically trapped particles is presented. Using a nanosecond pulsed laser, synchronized to the detection system, to exert a periodic driving force on an optically trapped 10 polystyrene bead, the laser pulse......-bead interaction is repeated hundreds of times. Traces with the bead position following the prompt displacement from equilibrium, induced by each laser pulse, are averaged and reveal the underlying deterministic motion of the bead, which is not visible in a single trace due to thermal noise. The motion of the bead...

  19. Breaking down the wall: fractionation of mycobacteria.

    Science.gov (United States)

    Rezwan, Mandana; Lanéelle, Marie-Antoinette; Sander, Peter; Daffé, Mamadou

    2007-01-01

    Mycobacterium spp. possess a complex cell envelope that consists of a plasma membrane, a peptidoglycan-arabinogalactan complex which in turn is esterified by mycolic acids that form with other non-bound lipids an asymmetric permeability barrier and an outer layer, also called a capsule in the case of pathogenic species. In order to investigate the functional roles of the cell envelope components, especially those of the major pathogens Mycobacterium tuberculosis and Mycobacterium leprae, it is necessary to fractionate the envelope by breaking the unusual wall that covers these bacteria. To this aim we first compared the efficiency of high pressure (cell disrupter/French press) with those of pathogen-compatible breakage methods such as sonication, bead beater and lysozyme treatment using the non-pathogenic Mycobacterium smegmatis. When the distribution of various specific markers of the cell envelope compartments, which include mycolic acids, arabinose, NADH oxidase activity, cell wall and cytosolic proteins, were determined sonication combined with lysozyme treatment was found to be the best option. The protocol of subcellular fractionation was then validated for pathogenic species by applying the method to Mycobacterium bovis BCG cells, an attenuated strain of the M. tuberculosis complex. PMID:16839634

  20. Immobilization of horseradish peroxidase on modified chitosan beads.

    Science.gov (United States)

    Monier, M; Ayad, D M; Wei, Y; Sarhan, A A

    2010-04-01

    A method has been developed to immobilize horseradish peroxidase (HRP) on modified chitosan beads by means of graft copolymerization of polyethylacrylate in presence of potassium persulphate and Mohr's salt redox initiator. The activity of free and immobilized HRP was studied. FTIR spectroscopy and scanning electron microscopy were used to characterize HRP immobilization. The efficiency of the immobilization was investigated by examining the relative enzymatic activity of free enzyme before and after the HRP immobilization. The obtained values were found to reach 98.4%. The results show that the optimum temperature of immobilized HRP was 45 degrees C, which was identical to that of free enzyme, and the immobilized HRP exhibited a higher relative activity than that of free HRP over 45 degrees C. The optimal pH for immobilized HRP was 10, which was higher than that of the free HRP (pH 9.0), and the immobilization resulted in stabilization of enzyme over a broader pH range. The apparent kinetic constant value (K(m)) of immobilized HRP was 3.784 mmol ml(-1), which was higher than that of free HRP. On the other hand, the activity of immobilized HRP decreased slowly against time when compared to that of the free HRP, and could retain 65.8% residual activity after 6 consecutive cycles. PMID:20060854

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

    Energy Technology Data Exchange (ETDEWEB)

    Hahn H.; Calaga, R.; Jain, P.; Johnson, E.C.; Xu, W.

    2012-06-25

    Several past measurements of the Brookhaven ERL at superconducting temperature produced a long list of higher order modes (HOMs). The Niobium 5-cell cavity is terminated with HOM ferrite dampers that successfully reduce the Q-factors to tolerable levels. However, a number of undamped resonances with Q {ge} 10{sup 6} were found at 4 K and their mode identification remained as a goal for this paper. The approach taken here consists in taking different S{sub 21} measurements on a copper cavity replica of the ERL which can be compared with the actual data and also with Microwave Studio computer simulations. Several different S{sub 21} transmission measurements are used, including those taken from the fundamental input coupler to the pick-up probe across the cavity, between probes in a single cell, and between beam-position monitor probes in the beam tubes. Mode identification is supported by bead pulling with a metallic needle or a dielectric sphere that are calibrated in the fundamental mode. This paper presents results for HOMs in the first two dipole bands with the prototypical 958 MHz trapped mode, the lowest beam tube resonances, and high-Q modes in the first quadrupole band and beyond.

  2. Insights into the beaded filament of the eye lens

    International Nuclear Information System (INIS)

    Filensin (BFSP1) and CP49 (BFSP2) represent two members of the IF protein superfamily that are thus far exclusively expressed in the eye lens. Mutations in both proteins cause lens cataract and careful consideration of the detail of these cataract phenotypes alerts us to several interesting features concerning the function of filensin (BFSP1) and CP49 (BFSP2) in the lens. With the first filensin (BFSP1) mutation now having been reported to cause a recessive cataract phenotype, there is the suggestion that the mutation could predispose heterozygote carriers to the early onset of age-related nuclear cataract. In the case of CP49 (BFSP2), there are now three unrelated families who have been identified with a common E233Δ mutation. Very interestingly this is linked to myopia in one family. Despite the apparent phenotypic differences of the filensin (BFSP1) and CP49 (BFSP2) mutations, the data are still consistent with the beaded filament proteins being essential for lens function and specifically contributing to the optical properties of the lens. The fact that none of the mutations thus far reported affect either the conserved LNDR or TYRKLLEGE motifs that flank the central rod domain supports the view that this pair of IF proteins have unusual structural features and a distinctive assembly mechanism. The multiple sequence divergences suggest these proteins have been adapted to the specific functional requirements of lens fibre cells, a function that can be traced from squid to man

  3. DNA entropic elasticity for short molecules attached to beads

    CERN Document Server

    Li, J; Nelson, P C; Li, Jinyu; Nelson, Philip C.

    2006-01-01

    Single-molecule experiments in which force is applied to DNA or RNA molecules have enabled important discoveries of nucleic acid properties and nucleic acid-enzyme interactions. These experiments rely on a model of the polymer force-extension behavior to calibrate the experiments; typically the experiments use the worm-like chain (WLC) theory for double-stranded DNA and RNA. This theory agrees well with experiments for long molecules. Recent single-molecule experiments have used shorter molecules, with contour lengths in the range of 1-10 persistence lengths. Most WLC theory calculations to date have assumed infinite molecule lengths, and do not agree well with experiments on shorter chains. Key physical effects that become important when shorter molecules are used include (i) boundary conditions which constrain the allowed fluctuations at the ends of the molecule and (ii) rotational fluctuations of the bead to which the polymer is attached, which change the apparent extension of the molecule. We describe the...

  4. 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.

  5. 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

    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...... 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, 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...

  6. Encapsulation of lactase (β-galactosidase) into κ-carrageenan-based hydrogel beads: Impact of environmental conditions on enzyme activity.

    Science.gov (United States)

    Zhang, Zipei; Zhang, Ruojie; Chen, Long; McClements, David Julian

    2016-06-01

    Encapsulation of enzymes in hydrogel beads may improve their utilization and activity in foods. In this study, the potential of carrageenan hydrogel beads for encapsulating β-galactosidase was investigated. Hydrogel beads were fabricated by injecting an aqueous solution, containing β-galactosidase (26 U) and carrageenan (1 wt%), into a hardening solution (5% potassium chloride). Around 63% of the β-galactosidase was initially encapsulated in the hydrogel beads. Encapsulated β-galactosidase had a higher activity than that of the free enzyme over a range of pH and thermal conditions, which was attributed to the stabilization of the enzyme structure by K(+) ions within the carrageenan beads. Release of the enzyme from the beads was observed during storage in aqueous solutions, which was attributed to the relatively large pore size of the hydrogel matrix. Our results suggest that carrageenan hydrogel beads may be useful encapsulation systems, but further work is needed to inhibit enzyme leakage. PMID:26830562

  7. Degradation and destruction of historical blue-green glass beads: a study using microspectroscopy of light transmission

    International Nuclear Information System (INIS)

    Blue-green historical beads are sometimes described as unstable because of their degradability. At present, it is not known what causes the deterioration of these beads. We explore the internal microstucture of degrading blue-green historical beads and its evolution in the process of bead deterioration. Investigating the transmittance and scattering spectra of visible and near infrared light we observe the formation of microscopic internal inhomogeneities of sizes less than 150 nm in the glass bulk, and growth of their density with an increase in the degree of bead degradation. By means of laser scanning microscopy we also observe numerous microinclusions and microcracks on the cleavage surface of a partially degraded bead. We discuss possible physical factors resulting in the destruction of the blue-green beads

  8. On-chip measurements of Brownian relaxation of magnetic beads with diameters from 10 nm to 250 nm

    DEFF Research Database (Denmark)

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

    2013-01-01

    We demonstrate the use of planar Hall effect magnetoresistive sensors for AC susceptibility measurements of magnetic beads with frequencies ranging from DC to 1 MHz. This wide frequency range allows for measuring Brownian relaxation of magnetic beads with diameters ranging from 10 nm to 250 nm. B...... sedimentation, magnetic trapping, and signal per bead. Among the investigated beads, we conclude that the beads with a nominal diameter of 80 nm are best suited for future on-chip volume-based biosensing experiments using planar Hall effect sensors.......We demonstrate the use of planar Hall effect magnetoresistive sensors for AC susceptibility measurements of magnetic beads with frequencies ranging from DC to 1 MHz. This wide frequency range allows for measuring Brownian relaxation of magnetic beads with diameters ranging from 10 nm to 250 nm...

  9. 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.

  10. Extraction of strontium ions using crown ether functionalized polyacrylamide gel beads

    International Nuclear Information System (INIS)

    A simple set-up has been developed for the synthesis of polyacrylamide (PAAm) gel beads functionalized with 4-acrylamido benzo 18-crown-6(CE) using sedimentation polymerization method. We report here the synthesis of CE functionalized PAAm beads. These beads have been used for the extraction of Sr2+ ions in water and in 4N HNO3 media. With the aid of Atomic Absorption Spectroscopy (AAS), the concentration of Sr2+ ions in aqueous phase before and after extraction was measured. Preliminary experiments have shown that the extraction efficiency is around 98% in deionized water and no extraction in 4N HNO3. The elution of Sr2+ ions from the CE functionalized PAAm gel beads was done in 4N HNO3 and found to be about 72%. (author)

  11. 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.

  12. Antibody-Conjugated Paramagnetic Nanobeads: Kinetics of Bead-Cell Binding

    Directory of Open Access Journals (Sweden)

    Shahid Waseem

    2014-05-01

    Full Text Available Specific labelling of target cell surfaces using antibody-conjugated paramagnetic nanobeads is essential for efficient magnetic cell separation. However, studies examining parameters determining the kinetics of bead-cell binding are scarce. The present study determines the binding rates for specific and unspecific binding of 150 nm paramagnetic nanobeads to highly purified target and non-target cells. Beads bound to cells were enumerated spectrophotometrically. Results show that the initial bead-cell binding rate and saturation levels depend on initial bead concentration and fit curves of the form A(1 − exp(−kt. Unspecific binding within conventional experimental time-spans (up to 60 min was not detectable photometrically. For CD3-positive cells, the probability of specific binding was found to be around 80 times larger than that of unspecific binding.

  13. Sorption of uranium from aqueous solution using chitosan-tripolyphosphate (TPP) beads

    International Nuclear Information System (INIS)

    Chitosan tripoyiphosphate (CH-TPP) beads were prepared using in-liquid curing method and used for adsorption of uranium from aqueous solution. Beads having with higher cross linking density is found to have better adsorption capacity for uranium. pH 5 is found to be the optimum solution conditions for the sorption of uranium using the higher crosslinked CH-TPP beads. Adsorption is found to be a slow process extending to 3-4 days. Experimental data is found to not fitting with either Langmuir or Freundlich isotherm probably due to poor diffusion of bulky uranium species into dense and glassy chitosan beads. Kinetics of sorption is found to be governed by the intraparticular diffusion which can be described by Fickian law. (author)

  14. Synthesis and characterization of chitosan impregnated calcium alginate beads for removal of uranium from aquatic stream

    International Nuclear Information System (INIS)

    The present study was conducted to study the feasibility of chitosan impregnated calcium alginate beads (Cal-Alg-Chi) to sorb the excess uranium from the aquatic stream. Chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). The optimal composition of calcium alginate chitosan beads is 4 % (wt/vol) alginate gel having 5% loading of chitosan. The nature and morphology of pure and uranium sorbed calcium alginate chitosan beads were characterized by scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS), and attenuated total reflectance Fourier transform infrared spectroscopy (ATRFTIR). The results of batch sorption experiments suggest that Cal-Alg-Chi beads are very effective for removal of uranium in the pH range of 2.0-5.0 and sorption is more than 80 % in the concentration range of 1-100 mgL-1

  15. Tumour metastasis-associated gene profiling using one-dimensional microfluidic beads array

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Great efforts have been made on the early diagnosis and molecular mechanism research of tumour metastasis in recent years. In this paper, based on the one-dimensional microfluidic beads array, a novel platform for tumour metastasis-associated genes profiling has been developed by depositing nucleic acids functional beads in the microchannel. This platform is sensitive (limit of detection: 0.02 nmol/L) and can perform mRNAs analysis without PCR. Two human colon cancer cell lines (primary and metastatic) from the same patient were used as a model, and transcriptional expression profiling of multiple tumour metastasis-associated genes in these two cell lines was successfully achieved. Furthermore, the results obtained on the beads array were validated by RT-PCR. This novel beads array has advantages of high sensitivity, little sample consumption, short assay time, low cost and high throughput capability. It holds the potential in early diagnosis and mechanism research of tumour metastasis.

  16. Removal of hexavalent chromium from aqueous solution by barium ion cross-linked alginate beads

    Directory of Open Access Journals (Sweden)

    Uzaşçı Sesil

    2014-07-01

    Full Text Available Barium ion cross-linked alginate beads have shown great affinity to toxic hexavalent chromium ions in aqueous solution, contrary to the traditional calcium alginate beads. The adsorption experiments were carried out by the batch contact method. The optimal pH for removal was found to be pH 4. The equilibrium was established in 4 h and the removal efficiency of chromium (VI was found as 95%. The adsorption data fit well with Langmuir and Freundlich isotherms. The maximum chromium (VI adsorption capacity determined from Langmuir isotherm was 36.5 mg/g dry alginate beads. Our study suggests that barium alginate beads can be used as cost-effective and efficient adsorbents for the removal of chromium (VI from contaminated waters.

  17. 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...

  18. STUDY ON THE SYNTHESIS AND STRUCTURE OF MACRORETICULAR BEAD PAN/PVC IPN RESINS

    Institute of Scientific and Technical Information of China (English)

    LI Yanfeng; ZHUO Renxi

    1993-01-01

    Macroreticular bead PAN/PVC IPN reans with cyano and chloro groups were synthesized by interpenetrating polymerization of acrylonitrile, or acrylonitrile and divinylbenzene into a macroporous polyvinyl chloride bead. The composition and structure of the bead IPN resins have been investigated by means of FT-IR, NMR, SEM, mercury porosimetry and elemental analysis. During the process of interpenetrating polymerization, the chain propagation obeys Bernoullian statistical law, and no grafting polymerization has been observed. The content of cyano group in the resulting IPN resins can be adjusted by the amount of acrylonitrile added. The morphology of the IPN resins basically resembles that of the polyvinyl chloride bead,whereas the pore structures vary to a certain degree

  19. A control system for uniform bead in fillet arc welding on tack welds

    International Nuclear Information System (INIS)

    Positioning a workpiece accurately and preventing weld distortion, tack welding is often adopted before main welding in the construction of welded structures. However, this tack weld deteriorates the final weld bead profile, so that the grinding process is usually performed for a uniform weld bead profile. In this study, a control system for uniform weld bead is proposed for the fillet arc welding on tack welds. The system consists of GMA welding machine, torch manipulator, laser vision sensor for measuring the tack weld size and the database for optimal welding conditions. Experiments have been performed for constructing the database and for evaluating the control capability of the system. It has been shown that the system has the capability to smooth the bead at the high level of quality

  20. Design and Evaluation of Stomach-Specific Drug Delivery of Domperidone using Floating Pectin Beads

    Directory of Open Access Journals (Sweden)

    K.Varun Kumar

    2013-03-01

    Full Text Available The objective of present study was to develop floating beads of Domperidone (DOM in order to increase its residence time in the stomach without contact with the mucosa, improve patient compliance and obtain improved therapeutic efficacy. They are prepared by extrusion congealing technique with pectin as a polymer. Floating beads were characterized by polymer compatibility by using FT-IR. The prepared beads were evaluated for particle size, surface morphology, buoyancy, actual drug content, entrapment efficiency and in vitro drug release. Nine formulations of DOM floating beads were formulated by using different percentage of both gas forming agent and pectin. Density of the formulated beads was found to be ranging between 0.101 and 0.182 g/cm3. The particle size was distributed between 0.6 to 1.6 mm. Buoyancy percentage was 71-87% and Drug entrapment efficiency was 54.4-64.48%. The micrometric properties were found to be good and scanning electron microscopy (SEM confirmed their hollow structure with smooth surface. The content of drug release was done by UV spectrophotometer at 284 nm. In vitro drug release of DOM, for F2 is 81.10% and for F6 is 82.6%. And the beads formulated using 0.3w/w (F2 and 0.4% w/w (F6 of pectin was more uniform in shape and exhibited maximum buoyancy. The drug content of the formulated beads was found to be satisfactory by this method. It remains in the gastric region for several hours and hence prolongs the gastric residence time of drug. From the study it was concluded that the gastro retentive drug delivery system designed as floating beads could be suitable drug delivery system for DOM.

  1. Design criteria for developing low-resource magnetic bead assays using surface tension valves.

    Science.gov (United States)

    Adams, Nicholas M; Creecy, Amy E; Majors, Catherine E; Wariso, Bathsheba A; Short, Philip A; Wright, David W; Haselton, Frederick R

    2013-01-01

    Many assays for biological sample processing and diagnostics are not suitable for use in settings that lack laboratory resources. We have recently described a simple, self-contained format based on magnetic beads for extracting infectious disease biomarkers from complex biological samples, which significantly reduces the time, expertise, and infrastructure required. This self-contained format has the potential to facilitate the application of other laboratory-based sample processing assays in low-resource settings. The technology is enabled by immiscible fluid barriers, or surface tension valves, which stably separate adjacent processing solutions within millimeter-diameter tubing and simultaneously permit the transit of magnetic beads across the interfaces. In this report, we identify the physical parameters of the materials that maximize fluid stability and bead transport and minimize solution carryover. We found that fluid stability is maximized with ≤0.8 mm i.d. tubing, valve fluids of similar density to the adjacent solutions, and tubing with ≤20 dyn/cm surface energy. Maximizing bead transport was achieved using ≥2.4 mm i.d. tubing, mineral oil valve fluid, and a mass of 1-3 mg beads. The amount of solution carryover across a surface tension valve was minimized using ≤0.2 mg of beads, tubing with ≤20 dyn/cm surface energy, and air separators. The most favorable parameter space for valve stability and bead transport was identified by combining our experimental results into a single plot using two dimensionless numbers. A strategy is presented for developing additional self-contained assays based on magnetic beads and surface tension valves for low-resource diagnostic applications. PMID:24403996

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

    International Nuclear Information System (INIS)

    Highlights: ► Magnetic beads were prepared for removal of diethyl phthalate (DEP). ► Total capacity of the beads was determined as 98.9 mg DEP per gram polymer. ► Magnetic beads were regenerated easily and reused for DEP adsorption. ► Adsorption isotherms, kinetics and thermodynamics were elucidated. - Abstract: The barium hexaferrite (BaFe12O19) containing magnetic poly(ethylene glycol dimethacrylate–vinyl pyridine), (mag-poly(EGDMA–VP)) beads (average diameter = 53–212 μm) 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 N2 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 °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.

  4. Poly(GMA/MA/MBAA) Copolymer Beads: a Highly Efficient Support Immobilizing Penicillin G Acylase

    Institute of Scientific and Technical Information of China (English)

    Ping XUE; Guan Zhong LU; Wan Yi LIU

    2006-01-01

    The hydrophilic, macroporous and beaded ternary copolymer of glycidyl methacrylate (GMA)/methacrylamide(MA)/N,N'-methylene-bis(acrylamide)(MBAA)was synthesized using the industrial agents by inverse suspension polymerization. The apparent activity of the immobilized penicillin G acylase reached 1096 IU/g for hydrolysis penicillin G on the beads with diameter of 0.11-0.13 mm, and it changed hardly after 50 cycles. It can be expected to be a good potential in industrial application.

  5. Injection of porous polycaprolactone beads containing autologous myoblasts in a dog model of fecal incontinence

    OpenAIRE

    Kang, Sung-Bum; Lee, Hye Seung; Lim, Jae-Young; Oh, Se Heang; Kim, Sang Joon; Hong, Sa-Min; Jang, Je-Ho; Cho, Jeong-Eun; Lee, Sung-Min; Lee, Jin Ho

    2013-01-01

    Purpose Few studies have examined whether bioengineering can improve fecal incontinence. This study designed to determine whether injection of porous polycaprolactone beads containing autologous myoblasts improves sphincter function in a dog model of fecal incontinence. Methods The anal sphincter of dogs was injured and the dogs were observed without and with (n = 5) the injection of porous polycaprolactone beads containing autologous myoblasts into the site of injury. Autologous myoblasts pu...

  6. Phos-tag beads as an immunoblotting enhancer for selective detection of phosphoproteins in cell lysates

    OpenAIRE

    Kinoshita, Eiji; Kinoshita-Kikuta, Emiko; Koike, Tohru

    2009-01-01

    The low specificity of anti-phosphoprotein antibodies is often a problem in immunoblotting analyses. We introduce a simple pretreatment procedure for cell lysates to give more-specific detection of phosphoproteins in immunoblotting. Cellular phosphoproteins were preferentially trapped on Phos-tag agarose phosphate-affinity beads in a homemade spin-centrifuge microtube unit, and nonphosphorylated proteins were excluded in the filtrate. The phosphoprotein-bound beads suspended in a sample-loadi...

  7. Effects of Sample Delivery on Analyte Capture in Porous Bead Sensors

    OpenAIRE

    Chou, Jie; Li, Luanyi E.; Kulla, Eliona; Christodoulides, Nicolaos; Floriano, Pierre N.; McDevitt, John T.

    2012-01-01

    Sample delivery is a crucial aspect of point-of-care applications where sample volumes need to be low and assay times need to be short, while providing high analytical and clinical sensitivity. In this paper, we explore the influence of the factors surrounding sample delivery on analyte capture in an immunoassay-based sensor array manifold of porous beads resting in individual wells. We model using computational fluid dynamics and a flow-through device containing beads sensitized specifically...

  8. On-chip magnetic separation of superparamagnetic beads for integrated molecular analysis

    OpenAIRE

    Florescu, Octavian; Wang, Kevan; Au, Patrick; Tang, Jimmy; Harris, Eva; Beatty, P. Robert; Boser, Bernhard E.

    2010-01-01

    We have demonstrated a postprocessed complementary metal oxide semiconductor (CMOS) integrated circuit (IC) capable of on-chip magnetic separation, i.e., removing via magnetic forces the nonspecifically bound magnetic beads from the detection area on the surface of the chip. Initially, 4.5 μm wide superparamagnetic beads sedimenting out of solution due to gravity were attracted to the detection area by a magnetic concentration force generated by flowing current through a conductor embedded in...

  9. Arsenate removal by layered double hydroxides embedded into spherical polymer beads: Batch and column studies.

    Science.gov (United States)

    Nhat Ha, Ho Nguyen; Kim Phuong, Nguyen Thi; Boi An, Tran; Mai Tho, Nguyen Thi; Ngoc Thang, Tran; Quang Minh, Bui; Van Du, Cao

    2016-01-01

    In this study, the performance of poly(layered double hydroxides) [poly(LDHs)] beads as an adsorbent for arsenate removal from aqueous solution was investigated. The poly(LDHs) beads were prepared by immobilizing LDHs into spherical alginate/polyvinyl alcohol (PVA)-glutaraldehyde beads (spherical polymer beads). Batch adsorption studies were conducted to assess the effect of contact time, solution pH, initial arsenate concentrations and co-existing anions on arsenate removal performance. The potential reuse of these poly(LDHs) beads was also investigated. Approximately 79.1 to 91.2% of arsenic was removed from an arsenate solution (50 mg As L(-1)) by poly(LDHs). The adsorption data were well described by the pseudo-second-order kinetics model and the Langmuir isotherm model, and the adsorption capacities of these poly(LDHs) beads at pH 8 were from 1.64 to 1.73 mg As g(-1), as calculated from the Langmuir adsorption isotherm. The adsorption ability of the poly(LDHs) beads decreased by approximately 5-6% after 5 adsorption-desorption cycles. Phosphates markedly decreased arsenate removal. The effect of co-existing anions on the adsorption capacity declined in the following order: HPO4 (2-) > HCO3 (-) > SO4 (2-) > Cl(-). A fixed-bed column study was conducted with real-life arsenic-containing water. The breakthrough time was found to be from 7 to 10 h. Under optimized conditions, the poly(LDHs) removed more than 82% of total arsenic. The results obtained in this study will be useful for further extending the adsorbents to the field scale or for designing pilot plants in future studies. From the viewpoint of environmental friendliness, the poly(LDHs) beads are a potential cost-effective adsorbent for arsenate removal in water treatment. PMID:26818806

  10. Gold Bead Implantation in Acupoints for Coxofemoral Arthrosis in Dogs: Method Description and Adverse Effects

    OpenAIRE

    Lars Moe; Morten Devor; Øyvind Stigen; Jæger, Gry T.

    2012-01-01

    Simple Summary Traditional acupuncture uses needles inserted at certain acupuncture points. Gold bead implantation at acupuncture points is used in acupuncture intended to relieve pain in certain diseases. The method of gold implantation is not well described in the literature. We describe the technique of implanting 24-karat gold beads around the joints of dogs with degenerative joint disease due to chronic hip dysplasia. The method is safe and fairly easy to perform under anesthesia. It has...

  11. Synthesis and characterization of monosize magnetic poly(glycidyl methacrylate) beads

    Institute of Scientific and Technical Information of China (English)

    Evrim Banu Alt1nta(s); Lokman Uzun; Adil Denizli

    2007-01-01

    Monosize, 1.6 μm, magnetic beads of poly(glycidyl methacrylate) [M-poly(GMA)], were prepared by dispersion polymerization in the presence of Fe3O4 nano-powder. Monosize M-poly(GMA) beads were characterized by swelling tests, density measurements, electron spin resonance (ESR), vibrating sample magnetometer (VSM) and scanning electron microscopy (SEM). The characteristic functional groups of M-poly(GMA)beads were analyzed by Fourier transform infrared spectrometer (FTIR). The M-poly(GMA) beads are highly uniform in size and have a spherical shape and non-porous structure. Polydispersity index (PDI) of M-poly(GMA) beads was calculated to be around 1.008. The hydrated density of the M-poly(GMA) beads measured at 25 ℃ was 1.14 g/cm3. The content of oxirane groups on the surface of the M-poly(GMA) sample was found to be 3.46 mmol/g by using perchloric acid titration. The specific surface area of the M-poly(GMA) beads was determined to be 3.2 m2/g.The equilibrium swelling ratio was 52%. The volume fraction of magnetite nanopowder in the M-poly(GMA) beads was found to be 4.5%. The g factor, that can be considered as a quantity characteristic of the molecules in which the unpaired electrons are located, was found to be 2.28for M-poly(GMA). The external magnetic field at resonance was calculated to be 2055 Gs which was found sufficient to excite all of the dipole moments present in 1.0 g of M-poly(GMA) sample.

  12. Microfluidic immunomagnetic multi-target sorting – a model for controlling deflection of paramagnetic beads

    OpenAIRE

    Tsai, S S H; Griffiths, I. M.; Stone, H. A.

    2012-01-01

    We describe a microfluidic system that uses a magnetic field to sort paramagnetic beads by deflecting them in the direction normal to the flow. Our experiments systematically study the dependence of the beads’ deflection on: bead size and susceptibility, magnet strength, fluid speed and viscosity, and device geometry. We also develop a design parameter that can aid in the design of microfluidic devices for immunomagnetic multi-target sorting.

  13. Adsorption of doxorubicin on poly (methyl methacrylate) -chitosan-heparin coated activated carbon beads

    OpenAIRE

    Miao, Jianjun; Zhang, Fuming; Takieddin, Majde; Mousa, Shaker; Linhardt, Robert J.

    2012-01-01

    Extracorporeal filter cartridges, filled with activated carbon bead (ACB) adsorbent, have been used for removal of overdosed cancer drugs from the blood. Coatings on adsorbent matrices, poly (methyl methacrylate) (PMMA)/activated carbon bead and PMMA/chitosan/heparin/ACB composites, were tested to improve their biocompatibility and blood compatibility. PMMA coating on ACBs was accomplished in a straightforward manner using a PMMA solution in ethyl acetate. One-step hybrid coating of ACBs with...

  14. Effect of welding parameters of Gas Metal Arc welding on weld bead geometry: A Review

    Directory of Open Access Journals (Sweden)

    Pushp Kumar Baghel

    2012-07-01

    Full Text Available Weld quality comprises bead geometry and its microstructure, which influence the mechanical properties of the weld. This brief review illustrates the effect of pulse parameters on weld quality. The responsefactors, namely bead penetration, weld width, reinforcement height, weld penetration shape factor and weld reinforcement form factor as affected by arc voltage, wire feed rate, welding speed, gas flow rate and nozzle-toplate distance has also been analysed

  15. Archaeometric study of glass beads from the 2nd century BC cemetery of Numantia

    OpenAIRE

    García Heras, Manuel; Rincoón López, Jesús M.; Alfredo JIMENO MARTÍNEZ; Villegas Broncano, María Angeles

    2003-01-01

    Recent archaeologícalf ieldwork undertaken in the Celtiberian cremation necropolis of Numantia (Soria, Spain) has provided a group of glass beads from the 2nd century BC. Such glass beads were part, together with other metallic and ceramic items, of the offerings deposited with the dead. They are ring-shaped in typology and deep-blue, amber, or semitransparent white in colour. This paper reports results derived from the chemical and microstructural characterization carried out on a representa...

  16. EXPERIMENTAL TESTING OF DRAW—BEAD RESTRAINING FORCE IN SHEET METAL FORMING

    Institute of Scientific and Technical Information of China (English)

    J.H.Yang; J.Chen; 等

    2003-01-01

    Due to complexities of draw-bead restraining force calculated according to theory and depending on sheet metal forming properties experiment testing system,a simplified method to calculate draw-bead restraining force is put forward by experimental method in cup-shaped drawing process.The experimental results were compared with numer-ical results and proved agreement.It shows the method is effective.

  17. Evolution of enzyme catalysts caged in biomimetic gel-shell beads

    OpenAIRE

    Fischlechner, Martin; Schaerli, Yolanda; Mohamed, Mark F.; Patil, Santosh; Abell, Chris; Hollfelder, Florian

    2014-01-01

    Natural evolution relies on the improvement of biological entities by rounds of diversification and selection. In the laboratory, directed evolution has emerged as a powerful tool for the development of new and improved biomolecules, but it is limited by the enormous workload and cost of screening sufficiently large combinatorial libraries. Here we describe the production of gel-shell beads (GSBs) with the help of a microfluidic device. These hydrogel beads are surrounded with a polyelectroly...

  18. The effect of pharmaceutical excipients on isoniazid release from chitosan beads / Deon van Rensburg

    OpenAIRE

    Van Rensburg, Andries Gideon

    2007-01-01

    In controlled release applications a drug is molecularly dispersed in a polymer phase. In the presence of a thermodynamically compatible solvent, swelling occurs and the polymer releases its content to the surrounding medium. The rate of the drug release can be controlled by interfering with the swelling rate of the beads or by influencing diffusion through the viscosity of the polymer. Beads that contain chitosan were prepared through the ionotropic gelation method where tr...

  19. Immobilization of Lipase from Candida rugosa on Chitosan Beads for Transesterification Reaction

    OpenAIRE

    M. Nasratun; H. A. Said; Noraziah, A.; 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...

  20. Heme Iron Release from Alginate Beads at In Vitro Simulated Gastrointestinal Conditions.

    Science.gov (United States)

    Valenzuela, Carolina; Hernández, Valesca; Morales, María Sol; Pizarro, Fernando

    2016-07-01

    Heme iron (Fe) release from alginate beads at in vitro simulated gastrointestinal conditions for potential use as oral heme Fe supplement was studied. Five beads at different ratios of sodium alginate (SA)-to-spray-dried bovine blood cells (SDBC) with weight ratios of 1:1.25, 1:2.5, 1:5, 1:10, and 1:15 (w/w) were prepared. Release characteristics of these beads were investigated at in vitro simulated gastrointestinal conditions. Release media pH strongly influenced the controlled Fe release from the beads. The heme Fe-beads in simulated gastric fluid (pH 2) remained in a shrinkage state and Fe release was low: 25.8, 21.1, 11.6, 12.1, and 12.0 % for 1:1.25, 1:2.5, 1:5, 1:10, and 1:15 ratios, respectively. Proportion and amount of Fe released by 1:1.25 and 1:2.5 ratios was higher than the other ratios. The heme Fe-beads swelled and dissociated in simulated intestinal fluid (pH 6), releasing three-fourths of the Fe in 200 min. The morphology studies showed that Fe release followed formation of pores in the alginate matrix, generating erosion of the beads and complete disintegration after 75 and 200 min of gastric and intestinal incubation, respectively. These results indicate that heme Fe-beads may be useful for oral delivery of heme Fe supplement. PMID:26610684

  1. Effect of porous polycaprolactone beads on bone regeneration: preliminary in vitro and in vivo studies

    OpenAIRE

    Byun, June-Ho; Lee, Han A Reum; Kim, Tae Ho; Lee, Jin Ho; Oh, Se Heang

    2014-01-01

    Background For the effective bone regeneration with appropriate pathological/physiological properties, a variety of bone fillers have been adapted as a therapeutic treatment. However, the development of ideal bone fillers is still remained as a big challenge in clinical practice. The main aims of this study are i) fabrication of a highly porous PCL beads; and ii) the estimation of the potential use of the porous PCL beads as a bone filler through preliminary animal study. Results The porous P...

  2. 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. PMID:26485316

  3. 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.

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

    International Nuclear Information System (INIS)

    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.

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

    Science.gov (United States)

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

    2016-02-01

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

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

    Science.gov (United States)

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

    2016-01-01

    Detection and quantification of pathogens in water is critical for the protection of human health and for drinking water safety and security. When the pathogen concentrations are low, large sample volumes (several liters) are needed to achieve reliable quantitative results. However, most microbial identification methods utilize relatively small sample volumes. As a consequence, a concentration step is often required to detect pathogens in natural waters. Herein, we introduce a novel water sample concentration method based on superabsorbent polymer (SAP) beads. When SAP beads swell with water, small molecules can be sorbed within the beads, but larger particles are excluded and, thus, concentrated in the residual non-sorbed water. To illustrate this approach, millimeter-sized poly(acrylamide-co-itaconic acid) (P(AM-co-IA)) beads are synthesized and successfully applied to concentrate water samples containing two model microorganisms: Escherichia coli and bacteriophage MS2. Experimental results indicate that the size of the water channel within water swollen P(AM-co-IA) hydrogel beads is on the order of several nanometers. The millimeter size coupled with a negative surface charge of the beads are shown to be critical in order to achieve high levels of concentration. This new concentration procedure is very fast, effective, scalable, and low-cost with no need for complex instrumentation. PMID:26876979

  7. The influence of the degree of cross-linking on the adsorption properties of chitosan beads.

    Science.gov (United States)

    Osifo, Peter O; Webster, Athena; van der Merwe, Hein; Neomagus, Hein W J P; van der Gun, Marius A; Grant, David M

    2008-10-01

    The influence of the degree of cross-linking (DCL) on chitosan beads was studied. Chitosan was prepared from the exoskeleton of Cape rock-lobsters, collected from the surroundings of Cape Town, South Africa. The chitosan beads were characterized; the beads water contents and pKa varied in the range of 90-96% and 4.3-6.0, respectively, and were found to decrease with increasing DCL (0.0-34.0%). A pH-model, which described the reversibility of the metal adsorbed onto the beads, was used to predict the equilibrium properties of copper adsorption onto the cross-linked beads. The model accounts for the effect of pH and the important model parameters, the equilibrium adsorption constant (Kads) and to a lesser extent the adsorbent adsorption capacity (qmax) showed to decrease with the DCL. The adsorbent capacity and the adsorption constant were determined as 3.8-5.0mmol/g chitosan and (9-90)x10(-4), respectively. The adsorption kinetics could be described using a shrinking core model and the effective diffusion coefficient (Deff) was determined as (8.0-25.8)x10(-11)m2/s. It was found that Deff decreases with the DCL mainly due to the decreased in water content of the beads at high DCL. PMID:18342504

  8. Radiation synthesis of chitosan beads grafted with acrylic acid for metal ions sorption

    Energy Technology Data Exchange (ETDEWEB)

    Benamer, S., E-mail: benamers@yahoo.fr [Division of Nuclear Applications, Centre de Recherche Nucleaire d' Alger, BP-399 Alger-Gare (Algeria); Mahlous, M.; Tahtat, D.; Nacer-Khodja, A.; Arabi, M. [Division of Nuclear Applications, Centre de Recherche Nucleaire d' Alger, BP-399 Alger-Gare (Algeria); Lounici, H.; Mameri, N. [Ecole Nationale Polytechnique d' El-Harrach Alger (Algeria)

    2011-12-15

    Radiation-induced grafting of acrylic acid onto chitosan beads was performed in solution at a dose rate of 20.6 Gy/min of cobalt-60 gamma rays. The effect of absorbed dose on grafting yield was investigated. The characterization of the grafted material was performed by FTIR spectroscopy and the swelling measurements at different pHs. The grafting yield increased with the increase in dose, it reached 80% at 40 kGy irradiation dose. The removal of Pb and Cd ions from aqueous solutions was investigated with both ungrafted and grafted chitosan beads. The sorption behavior of the sorbents was examined through pH, kinetics and equilibrium measurements. Grafted chitosan beads presented higher sorption capacity for both metal ions than unmodified chitosan beads. - Highlights: > Pb and Cd ions are removed from aqueous solution by adsorption on chitosan beads. > Crosslinking process improves chemical stability of chitosan beads. > Radiation grafting of acrylic acid onto chitosan improves its metal adsorption capacity. > Increase in grafting degree enhances the adsorption capacity of the material. > Gamma radiation is a powerful tool for an accurate control of the grafting yield.

  9. Radiation synthesis of chitosan beads grafted with acrylic acid for metal ions sorption

    International Nuclear Information System (INIS)

    Radiation-induced grafting of acrylic acid onto chitosan beads was performed in solution at a dose rate of 20.6 Gy/min of cobalt-60 gamma rays. The effect of absorbed dose on grafting yield was investigated. The characterization of the grafted material was performed by FTIR spectroscopy and the swelling measurements at different pHs. The grafting yield increased with the increase in dose, it reached 80% at 40 kGy irradiation dose. The removal of Pb and Cd ions from aqueous solutions was investigated with both ungrafted and grafted chitosan beads. The sorption behavior of the sorbents was examined through pH, kinetics and equilibrium measurements. Grafted chitosan beads presented higher sorption capacity for both metal ions than unmodified chitosan beads. - Highlights: → Pb and Cd ions are removed from aqueous solution by adsorption on chitosan beads. → Crosslinking process improves chemical stability of chitosan beads. → Radiation grafting of acrylic acid onto chitosan improves its metal adsorption capacity. → Increase in grafting degree enhances the adsorption capacity of the material. → Gamma radiation is a powerful tool for an accurate control of the grafting yield.

  10. Floating mucoadhesive alginate beads of amoxicillin trihydrate: A facile approach for H. pylori eradication.

    Science.gov (United States)

    Dey, Sanjoy Kumar; De, Pintu Kumar; De, Arnab; Ojha, Souvik; De, Ronita; Mukhopadhyay, Asish Kumar; Samanta, Amalesh

    2016-08-01

    This study investigates the design of sunflower oil entrapped floating and mucoadhesive beads of amoxicillin trihydrate using sodium alginate and hydroxypropyl methylcellulose as matrix polymers and chitosan as coating polymer to localize the antibiotic at the stomach site against Helicobacter pylori. Beads prepared by ionotropic gellation technique were evaluated for different physicochemical, in-vitro and in-vivo properties. Beads of all batches were floated for >24h with a maximum lag time of 46.3±3.2s. Scanning electron microscopy revealed that the beads were spherical in shape with few oil filled channels distributed throughout the surfaces and small pocket structures inside the matrix confirming oil entrapment. Prepared beads showed good mucoadhesiveness of 75.7±3.0% to 85.0±5.5%. The drug release profile was best fitted to Higuchi model with non fickian driven mechanism. The optimized batch showed 100% Helicobacter pylori growth inhibition in 15h in in-vitro culture. Furthermore, X-ray study in rabbit stomach confirmed the gastric retention of optimized formulation. The results exhibited that formulated beads may be preferred to localize the antibiotic in the gastric region to allow more availability of antibiotic at gastric mucus layer acting on Helicobacter pylori, thereby improving the therapeutic efficacy. PMID:27177460

  11. Surface modification of glass beads with glutaraldehyde: Characterization and their adsorption property for metal ions

    International Nuclear Information System (INIS)

    In this study, a new material that adsorbs the metal ions was prepared by modification of the glass beads surfaces with glutaraldehyde. First, the glass beads were etched with 4 M NaOH solution. Then, they were reacted with 3-aminopropyl-triethoxysilane (APTES). Finally, silanized glass beads were treated with 25% of glutaraldehyde solution. The characterization studies by using Fourier Transform Infrared Spectroscopy (FT-IR), Thermal Gravimetric Analysis (TGA), elemental analysis and Scanning Electron Microscopy (SEM) indicated that modification of the glass bead surfaces was successfully performed. The adsorption studies exhibited that the modified glass beads could be efficiently used for the removal of the metal cations and anion (chromate ion) from aqueous solutions via chelation and ion-exchange mechanisms. For both Pb(II) and Cr(VI), selected as model ions, the adsorption equilibrium was achieved in 60 min and adsorption of both ions followed the second-order kinetic model. It was found that the sorption data was better represented by the Freundlich isotherm in comparison to the Langmuir and Redlich-Peterson isotherm models. The maximum adsorption capacities for Pb(II) and Cr(VI) were 9.947 and 11.571 mg/g, respectively. The regeneration studies also showed that modified glass beads could be re-used for the adsorption of Pb(II) and Cr(VI) from aqueous solutions over three cycles.

  12. Ispaghula mucilage-gellan mucoadhesive beads of metformin HCl: development by response surface methodology.

    Science.gov (United States)

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

    2014-07-17

    Response surface methodology based on 3(2) factorial design was used to develop ispaghula (Plantago ovata F.) husk mucilage (IHM)-gellan gum (GG) mucoadhesive beads containing metformin HCl through Ca(2+)-ion cross-linked ionotropic-gelation technique for the use in oral drug delivery. GG to IHM ratio and cross-linker (CaCl2) concentration were investigated as independent variables. Drug encapsulation efficiency (DEE, %) and cumulative drug release after 10h (R10h, %) were analyzed as dependent variables. The optimized mucoadhesive beads (F-O) showed DEE of 94.24 ± 4.18%, R10h of 59.13 ± 2.27%. These beads were also characterized by SEM and FTIR analyses. The in vitro drug release from these beads showed controlled-release (zero-order) pattern with super case-II transport mechanism over 10h. The optimized beads showed pH-dependent swelling and good mucoadhesivity with the goat intestinal mucosa. The optimized IHM-GG mucoadhesive beads containing metformin HCl exhibited significant antidiabetic effect in alloxan-induced diabetic rats over 10h. PMID:24702916

  13. Impact of gelation period on modified locust bean-alginate interpenetrating beads for oral glipizide delivery.

    Science.gov (United States)

    Dey, Paramita; Sa, Biswanath; Maiti, Sabyasachi

    2015-05-01

    In this work, the effect of hydrogelation period in the design of glipizide-loaded biopolymer-based interpenetrating network (IPN) beads was investigated. Carboxymethyl locust bean gum and sodium alginate IPN beads were prepared by ionic crosslinking method using aqueous aluminium chloride salt solution as gelation medium. The longer exposure of the IPN beads in the gelation medium caused a considerable loss of the drug (∼ 8%), and also affected their surface morphology and drug release performance. Spherical shape of the IPN beads was observed under scanning electron microscope (SEM). The diameter of IPN beads increased with increasing gelation time. The IPNs cured for 0.5h exhibited slower drug release kinetics in HCl (pH 1.2) and phosphate buffer (pH 7.4) solution than those incubated for 1-2h. The drug release occurred at a faster rate in phosphate buffer solution and continued for a minimum period of 8h. The IPNs cured for the lowest period obeyed polymer chain-relaxation phenomenon as dominating mechanism for drug release. However, all the IPNs followed anomalous mechanism of drug transport. The drug release corroborated well with pH-dependent swelling behaviors of the IPNs. Thus, IPN beads cured for 0.5h were found most suitable for controlled delivery of BCS class II anti-diabetic drug glipizide. PMID:25745842

  14. Self-assembled magnetic bead chains for sensitivity enhancement of microfluidic electrochemical biosensor platforms.

    Science.gov (United States)

    Armbrecht, L; Dincer, C; Kling, A; Horak, J; Kieninger, J; Urban, G

    2015-11-21

    In this paper, we present a novel approach to enhance the sensitivity of microfluidic biosensor platforms with self-assembled magnetic bead chains. An adjustable, more than 5-fold sensitivity enhancement is achieved by introducing a magnetic field gradient along a microfluidic channel by means of a soft-magnetic lattice with a 350 μm spacing. The alternating magnetic field induces the self-assembly of the magnetic beads in chains or clusters and thus improves the perfusion and active contact between the analyte and the beads. The soft-magnetic lattices can be applied independent of the channel geometry or chip material to any microfluidic biosensing platform. At the same time, the bead-based approach achieves chip reusability and shortened measurement times. The bead chain properties and the maximum flow velocity for bead retention were validated by optical microscopy in a glass capillary. The magnetic actuation system was successfully validated with a biotin-streptavidin model assay on a low-cost electrochemical microfluidic chip, fabricated by dry-film photoresist technology (DFR). Labelling with glucose oxidase (GOx) permits rapid electrochemical detection of enzymatically produced H2O2. PMID:26394820

  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. 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

    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...

  17. International Divider Walls

    NARCIS (Netherlands)

    Kruis, A.; Sneller, A.C.W.(L.)

    2013-01-01

    The subject of this teaching case is the Enterprise Resource Planning (ERP) system implementation at International Divider Walls, the world market leader in design, production, and sales of divider walls. The implementation in one of the divisions of this multinational company had been successful, a

  18. Thin Wall Iron Castings

    Energy Technology Data Exchange (ETDEWEB)

    J.F. Cuttino; D.M. Stefanescu; T.S. Piwonka

    2001-10-31

    Results of an investigation made to develop methods of making iron castings having wall thicknesses as small as 2.5 mm in green sand molds are presented. It was found that thin wall ductile and compacted graphite iron castings can be made and have properties consistent with heavier castings. Green sand molding variables that affect casting dimensions were also identified.

  19. Timber frame walls

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan de Place; Brandt, Erik

    2010-01-01

    A ventilated cavity is usually considered good practice for removing moisture behind the cladding of timber framed walls. Timber frame walls with no cavity are a logical alternative as they are slimmer and less expensive to produce and besides the risk of a two-sided fire behind the cladding is...

  20. The Humming Wall

    DEFF Research Database (Denmark)

    Morrison, Ann Judith; Manresa-Yee, Cristina; Jensen, Brian Walther Skovgaard; Eshraghi, Neda

    2016-01-01

    We observed interactions with The Humming Wall, a vibrotactile and vibroacoustic interactive artifact placed in an urban park. Prior studies have focused on interactivity with primarily vision based systems (or with this system, the interaction between the wall and a wearable vibrotactile vest...

  1. Skyrmions and domain walls

    OpenAIRE

    Piette, B.; Zakrzewski, W. J.

    1997-01-01

    We study the 3+1 dimensional Skyrme model with a mass term different from the usual one. We show that this new model possesses domain walls solutions. We describe how, in the equivalent 2+1 dimensional model, the Skyrmion is absorbed by the wall.

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

    Science.gov (United States)

    Hossieny, Nemat

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

  3. Recovery of uranium from phosphoric acid medium by polymeric composite beads encapsulating organophosphorus extractants

    International Nuclear Information System (INIS)

    The present study deals with the preparation and evaluation of the poly-ethersulfone (PES) based composite beads encapsulating synergistic mixture of D2EHPA and Cyanex 923 (at 4:1 mole ratio) for the separation of uranium from phosphoric acid medium. SEM was used for the characterization of the composite materials. Addition of 1% PVA (polyvinyl alcohol) improved the internal morphology and porosity of the beads. Additionally, microscopic examination of the composite bead confirmed central coconut type cavity surrounded by porous polymer layer of the beads through which exchange of metal ions take place. Effect of various experimental variables including aqueous acidity, metal ion concentration in aqueous feed, concentration of organic extractant inside the beads, extractant to polymer ratio, liquid to solid (L/S) ratio and temperature on the extraction of uranium was studied. Increase in acidity (1-6 M), L/S ratio (1- 10), metal ion concentration (0.2-3 g/L U3O8) and polymer to extractant ratio (1:4 -1:10) led to decrease in extraction of uranium. At 5.5 M (comparable to wet process phosphoric acid concentration) the extraction of uranium was about 85% at L/S ratio 5. Increase in extractant concentration inside the bead resulted in enhanced extraction of metal ion. Increase in temperature in the range of 30 to 50 Celsius degrees increased the extraction, whereas further increase to 70 C degrees led to the decrease in extraction of uranium. Amongst various reagents tested, stripping of uranium was quantitative by 12% Na2CO3 solution. Polymeric beads were found to be stable and reusable up-to 10 cycles of extraction/stripping. (authors)

  4. Recovery of uranium from phosphoric acid medium by polymeric composite beads encapsulating organophosphorus extractants

    Energy Technology Data Exchange (ETDEWEB)

    Singh, D.K.; Yadav, K.K.; Varshney, L.; Singh, H. [Bhabha Atomic Research Centre, Mumbai 400 085 (India)

    2013-07-01

    The present study deals with the preparation and evaluation of the poly-ethersulfone (PES) based composite beads encapsulating synergistic mixture of D2EHPA and Cyanex 923 (at 4:1 mole ratio) for the separation of uranium from phosphoric acid medium. SEM was used for the characterization of the composite materials. Addition of 1% PVA (polyvinyl alcohol) improved the internal morphology and porosity of the beads. Additionally, microscopic examination of the composite bead confirmed central coconut type cavity surrounded by porous polymer layer of the beads through which exchange of metal ions take place. Effect of various experimental variables including aqueous acidity, metal ion concentration in aqueous feed, concentration of organic extractant inside the beads, extractant to polymer ratio, liquid to solid (L/S) ratio and temperature on the extraction of uranium was studied. Increase in acidity (1-6 M), L/S ratio (1- 10), metal ion concentration (0.2-3 g/L U{sub 3}O{sub 8}) and polymer to extractant ratio (1:4 -1:10) led to decrease in extraction of uranium. At 5.5 M (comparable to wet process phosphoric acid concentration) the extraction of uranium was about 85% at L/S ratio 5. Increase in extractant concentration inside the bead resulted in enhanced extraction of metal ion. Increase in temperature in the range of 30 to 50 Celsius degrees increased the extraction, whereas further increase to 70 C degrees led to the decrease in extraction of uranium. Amongst various reagents tested, stripping of uranium was quantitative by 12% Na{sub 2}CO{sub 3} solution. Polymeric beads were found to be stable and reusable up-to 10 cycles of extraction/stripping. (authors)

  5. Analysis of surface properties of human cancer cells using derivatized beads.

    Science.gov (United States)

    Khurrum, Maria R; Weerasinghe, Gayani R; Soriano, Evelyn S; Riman, Rashad; Badali, Oliver; Gipson, Stephanie; Medina, Jessica; Alfaro, Juan; Navarro, Vanessa M; Harieg, Caroline B; Ngo, Lylla; Sakhakorn, Tharinee; Kirszenbaum, Lital; Khatibi, David; Abedi, Karolin; Barajas, Marcela; Zem, Gregory C; Kirszenbaum, Adit; Razi, Arash; Oppenheimer, Steven B

    2002-01-01

    Standard histochemical analysis of cells and tissues generally involves procedures that utilize a relatively small number of probes such as dyes, and generally requires hours or days to process. Our laboratory has developed a novel method for histochemical surveys of cell surface properties that utilizes a large number of probes (derivatized agarose beads) and takes seconds or minutes to accomplish. In this study, 4 human cell lines (CCL-255 (LS123) human colon cancer cells that are non-tumorigenic in nude mice; CRL-1459 (CCD-18CO) human colon endothelial cells that are non-malignant; CCL-220 (COLO 320DM) human colon cancer cells that are tumorigenic in nude mice; and HTB-171 (NCI H446) human lung carcinoma cells) were tested for their ability to bind to agarose beads derivatized with 51 different molecules. There were statistically significant differences in binding of the 4 cell types to all of the 51 types of beads, but 15 types of beads showed dramatic differences in binding to one or more of the 4 cell types. For example, only HTB-171 (NCI H446) bound to p-aminophenyl-beta-D-glucopyranoside-derivatized beads and only CCL-220 (COLO 320DM) bound to L-tyrosine-derivatized beads. The specificity of cell-bead binding was examined by performing assays in the presence or absence of exogenously added compounds in hapten-type of inhibition experiments. This assay, that utilizes large numbers of novel probes, may help in the development of new libraries of surface properties of specific cell types, with differing degrees of malignancy, that at this time could not be developed by using other available technologies. PMID:12389735

  6. Elemental analysis of bead samples using a laser-induced plasma at low pressure

    Energy Technology Data Exchange (ETDEWEB)

    Lie, Tjung Jie [Research Center of Maju Makmur Mandiri Foundation, 40 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia); Kurniawan, Koo Hendrik [Research Center of Maju Makmur Mandiri Foundation, 40 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia)]. E-mail: kurnia18@cbn.net.id; Kurniawan, Davy P. [Research Center of Maju Makmur Mandiri Foundation, 40 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia); Pardede, Marincan [Research Center of Maju Makmur Mandiri Foundation, 40 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia); Suliyanti, Maria Margaretha [Graduate Program in Opto Electrotechniques and Laser Applications, Faculty of Engineering, The University of Indonesia, 4 Salemba Raya, Jakarta 10430 (Indonesia); Khumaeni, Ali [Department of Physics, Faculty of Mathematics and Natural Sciences, Diponegoro University, Tembalang Campus, Semarang 50275 (Indonesia); Natiq, Shouny A. [Department of Physics, Faculty of Mathematics and Natural Sciences, Diponegoro University, Tembalang Campus, Semarang 50275 (Indonesia); Abdulmadjid, Syahrun Nur [Department of Physics, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Darussalam, Banda Aceh 23116 (Indonesia); Lee, Yong Inn [Physics Department, Chonbuk National University, Chonju 561-756, South Korea (Korea); Kagawa, Kiichiro [Department of Physics, Faculty of Education and Regional Studies, Fukui University, 9-1 bunkyo 3-chome, Fukui 910-8507 (Japan); Idris, Nasrullah [Department of Physics, Faculty of Education and Regional Studies, Fukui University, 9-1 bunkyo 3-chome, Fukui 910-8507 (Japan); Tjia, May On [Department of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, 10 Ganesha, Bandung 40132 (Indonesia)

    2006-01-15

    An Nd:YAG laser (1064 nm, 8 ns, 30 mJ) was focused on various types of fresh, fossilized white coral and giant shell samples, including samples of imitation shell and marble. Such samples are extremely important as material for preparing prayer beads that are extensively used in the Buddhist faith. The aim of this research was to develop a non-destructive method to distinguish original beads from their imitations by means of spectral measurements of the carbon, hydrogen, sodium and magnesium emission intensities and by measuring the hardness of the sample using the ratio between Ca (II) 396.8 nm and Ca (I) 422.6 nm. Based on these measurements, original fresh coral beads can be distinguished from any imitation made from hard wood. The same technique was also effective in distinguishing beads made of shell from its imitation. A spectral analysis of bead was also performed on a fossilized white coral sample and the result can be used to distinguish to some extent the fossilized white coral beads from any imitation made from marble. It was also found that the plasma plume should be generated at low ambient pressure to significantly improve the hydrogen and carbon emission intensity and also to avoid energy loss inside the crater during laser irradiation at atmospheric pressure. The results of this study confirm that operating the laser-induced plasma spectroscopy at reduced ambient pressure offers distinct advantage for bead analysis over the conventional laser-induced breakdown spectroscopy (LIBS) technique operated at atmospheric pressure.

  7. Elemental analysis of bead samples using a laser-induced plasma at low pressure

    International Nuclear Information System (INIS)

    An Nd:YAG laser (1064 nm, 8 ns, 30 mJ) was focused on various types of fresh, fossilized white coral and giant shell samples, including samples of imitation shell and marble. Such samples are extremely important as material for preparing prayer beads that are extensively used in the Buddhist faith. The aim of this research was to develop a non-destructive method to distinguish original beads from their imitations by means of spectral measurements of the carbon, hydrogen, sodium and magnesium emission intensities and by measuring the hardness of the sample using the ratio between Ca (II) 396.8 nm and Ca (I) 422.6 nm. Based on these measurements, original fresh coral beads can be distinguished from any imitation made from hard wood. The same technique was also effective in distinguishing beads made of shell from its imitation. A spectral analysis of bead was also performed on a fossilized white coral sample and the result can be used to distinguish to some extent the fossilized white coral beads from any imitation made from marble. It was also found that the plasma plume should be generated at low ambient pressure to significantly improve the hydrogen and carbon emission intensity and also to avoid energy loss inside the crater during laser irradiation at atmospheric pressure. The results of this study confirm that operating the laser-induced plasma spectroscopy at reduced ambient pressure offers distinct advantage for bead analysis over the conventional laser-induced breakdown spectroscopy (LIBS) technique operated at atmospheric pressure

  8. Solar Walls in tsbi3

    DEFF Research Database (Denmark)

    Wittchen, Kim Bjarne

    tsbi3 is a user-friendly and flexible computer program, which provides support to the design team in the analysis of the indoor climate and the energy performance of buildings. The solar wall module gives tsbi3 the capability of simulating solar walls and their interaction with the building. This...... version, C, of tsbi3 is capable of simulating five types of solar walls say: mass-walls, Trombe-walls, double Trombe-walls, internally ventilated walls and solar walls for preheating ventilation air. The user's guide gives a description of the capabilities and how to simulate solar walls in tsbi3....

  9. Uptake of fluorescent nano beads into BY2-cells involves clathrin-dependent and clathrin-independent endocytosis.

    Science.gov (United States)

    Bandmann, Vera; Müller, Jasmin Daniela; Köhler, Tim; Homann, Ulrike

    2012-10-19

    To follow endocytosis in BY-2 cells we made use of fluorescent nano beads. Beads with 20nm in diameter were internalised rapidly and accumulated partially in compartments also labelled by the endocytic marker FM4-64. Studies in BY-2 cells and protoplasts revealed that larger beads (100nm) were excluded from uptake into turgescent and plasmolysed cells while protoplasts were able to internalise beads with a diameter of up to 1000nm. Endocytosis of beads was only partially inhibited by the clathrin-specific inhibitor Ikarugamycin and strongly blocked by wortmannin. These results imply that uptake of beads involves clathrin-dependent and clathrin-independent endocytic mechanisms and supports the hypothesis that clathrin-independent endocytosis plays a general role in plants. PMID:23046971

  10. First wall for NET

    International Nuclear Information System (INIS)

    In collaboration with ANSALDO and within the frame of the European Fusion Tecnology Task N1 (Plasma Facing Components Design Studies), ENEA has performed a design an manufacturing feasibility study for the first wall of the Next European Torus (NET) during its ''physics'' operation phase. The main design specifications are average neutron wall load=1 MW/m2, peak surface heat flux=0.4 MW/m2, total number of burn pulses=1*104, average burn pulse duration=100 s, average neutron fluence=0.03 MWy/m2, structure material=AISI 316L SA, coolant=H2O at 50/100 centigrates (in/out). The reference ENEA-ANSALDO design is based on the use of flat plates coupled by microbrazing to poloidal cooling tubes. The technological development work has led to the design and manufacturing of a representative NET first wall box segment (0.65x 0.25x0.15 m) mockup which will be tested in the 190 kW Thermal Fatique Test Facility at JRC-Ispra. In this paper, we report on the various aspects of the basic experimental and theoretical investigations on the plasma-wall interactions for adequate protection of the first wall against erosion, global stress analysis of the first wall box, thecnological tests on brazed joints, and disign and manufacturing of the first wall mockup

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

    OpenAIRE

    Safaradeen Olateju Kareem; Olayinka Quadri Adio; Michael Bamitale Osho

    2014-01-01

    The potential of polysaccharide Irvingia gabonensis matrix as enzyme immobilization support was investigated. Lipase of Aspergillus niger F7-02 was immobilized by entrapment using glutaraldehyde as the cross-linking agent and stabilized in ethanolic-formaldehyde solution. The pH and temperature stability and activity yield of the immobilized enzyme were determined. Such parameters as enzyme load, bead size, number of beads, and bead reusability were also optimized. Adequate gel strength to fo...

  12. Nitrogen and Phosphorus Removal in the Recirculating Aquaculture System with Water Treatment Tank containing Baked Clay Beads and Chinese Cabbage

    OpenAIRE

    Aeknarin Thanakitpairin; Wiboonluk Pungrasmi; Sorawit Powtongsook

    2014-01-01

    This research aims to describe the nitrogen and phosphorus removal in Recirculating Aquaculture System (RAS) by crop plants biomass production. The 3 experiment systems consisted of 1 treatment (fish tank + baked clay beads + Chinese cabbage) and 2 controls as control-1 (fish tank only) and control-2 (fish tank + baked clay beads), were performed. With all experimental RAS, Nile tilapia (Oreochromis niloticus) was cultured at 2 kg/m3 density. The baked clay beads (8-16 mm in diameter) were fi...

  13. 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

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

    International Nuclear Information System (INIS)

    Poly(ethylene glycol dimethacrylate-n-vinyl imidazole) [poly(EGDMA-VIM)] hydrogel (average diameter 150-200 μm) 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 m2/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 HNO3. These features make poly(EGDMA-VIM) beads potential candidate adsorbent for heavy metal removal

  15. Plasma-wall interactions

    International Nuclear Information System (INIS)

    The plasma wall interactions for two extreme cases, the 'vacuum model' and the 'cold gas blanket' are outlined. As a first step for understanding the plasma wall interactions the elementary interaction processes at the first wall are identified. These are energetic ion and neutral particle trapping and release, ion and neutral backscattering, ion sputtering, desorption by ions, photons and electrons and evaporation. These processes have only recently been started to be investigated in the parameter range of interest for fusion research. The few measured data and their extrapolation into regions not yet investigated are reviewed

  16. Formulation of nano-zinc oxide into biocomposite beads for dye decolorization

    Science.gov (United States)

    Elkady, M. F.; Hassan, H. Shokry; El-Shazly, A. H.

    2015-03-01

    Zinc oxide nano-powder was prepared using sol-gel technique to be encapsulated onto polymeric blend composed from alginate and polyvinyl alcohol to fabricate novel bio-composite beads of nano-zinc oxide. The XRD patterns of both zinc oxide nano-powder and its polymeric hybrid were crystalline in their nature. The FTIR analysis of the fabricated ZnO polymeric hybrid confirms the binding between zinc oxide and the polymeric matrix. The BET analysis demonstrated that the calculated specific surface area of the formulated ZnO beads that equal to 22.8 m2/g is comparatively less than that of the free ZnO nano-powdered that equivalent to 64.9 m2/g. The thermal stability of ZnO nano-powdered 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 1500rpm. Moreover, this hybrid beads are chemically stable at the acidic media. The formulated ZnO hybrid beads verified to be good adsorbent material for C.I basic blue 41 (CB41).

  17. Am/Cm TTR testing - 3/8-inch glass beads evaluation in CIM5

    International Nuclear Information System (INIS)

    To facilitate the procurement and handling of the glass former for Am/Cm vitrification in the F-Canyon MPPF, 1/4 inch and 3/8 inch diameter glass beads were purchased from Corning for evaluation in the 5 inch Cylindrical Induction Melter (CIM5). Prior to evaluating the beads in the CIM5, tests were conducted in the Drain Tube Test Stand (DTTS) with 1/4 inch beads, 3/8 inch beads, and a 50/50 mixture to identify any process concerns. Results of the DTTS tests are summarized in Attachment 1. A somewhat larger volume expansion was experienced in all three DTTS runs as compared to a standard run using cullet. Further testing of the use of glass beads in the CIM5 was requested by the Design Authority as Task 1.02 of Technical Task Request 99-MNSS/SE-006. Since the Technical Task Plan was not yet approved, the completion of this task was conducted under an authorization request approved by the SRTC Laboratory Director, S. Wood. This request is included as Attachment 2

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

    International Nuclear Information System (INIS)

    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.)

  19. 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. PMID:27612820

  20. Radiation grafting of ionically crosslinked alginate/chitosan beads with acrylic acid for lead sorption

    International Nuclear Information System (INIS)

    Radiation-induced grafting of acrylic acid onto alginate/chitosan beads was performed in solution at a dose rate of 20.6 Gy/min of Co-60 gamma rays. The effect of absorbed dose on grafting yield was investigated. The characterization of the grafted and un-grafted beads was performed by FTIR spectroscopy and the swelling measurements at different pHs was studied. It is found that as the pH value increases the swelling degree increases up to pH 6 but with further increase in pH value the swelling decreases. Also, it is noticed that the grafting yield increased with increase the irradiation dose. Both un-grafted and grafted alginate/chitosan beads were examined as sorbents for the removal of Pb ions from aqueous solutions. The sorption behavior of the sorbents was examined through pH, and equilibrium measurements. Grafted alginate/chitosan beads presented higher sorption capacity for Pb ions than un-grafted beads. (author)

  1. Formulation, Evaluation and Optimization of Pectin- Bora Rice Beads for Colon Targeted Drug Delivery System

    Directory of Open Access Journals (Sweden)

    Kuldeep Hemraj Ramteke

    2014-03-01

    Full Text Available Purpose: The purpose of this research was to established new polysaccharide for the colon targeted drug delivery system, its formulation and in vitro and in vivo evaluation. Methods: Microspheres containing pectin and bora rice were prepared by ionotropic gelation technique using zinc acetate as cross linking agent and model drug used was glipizide. A 32 full factorial design was employed to study the effect of independent variables, polymer to drug ratio (A, and concentration of cross linking agent (B on dependent variables, particle size, swelling index, drug entrapment efficiency and percentage drug release. Results: Results of trial batches indicated that polymer to drug ratio and concentration of cross linking agent affects characteristics of beads. Beads were discrete, spherical and free flowing. Beads exhibited small particle size and showed higher percentage of drug entrapment efficiency. The optimized batch P2 exhibited satisfactory drug entrapment efficiency 68% and drug release was also controlled for more than 24 hours. The polymer to drug ratio had a more significant effect on the dependent variables. In vivo gamma scintigraphy study of optimized pectin-bora rice beads demonstrated degradation of beads whenever they reached to the colon. Conclusion: Bora rice is potential polysaccharide for colon targeted drug delivery system.

  2. PREPARATION AND CHARACTERIZATION OF CINNARIZINE FLOATING OIL ENTRAPPED CALCIUM ALGINATE BEADS

    Directory of Open Access Journals (Sweden)

    Mowafaq M. Ghareeb et al.

    2012-02-01

    Full Text Available Gastroretentive delivery systems can be retained in the stomach and assist in improving absorption and consequently the bioavailability of drug that has a narrow absorption window in a particular region of gastrointestinal tract. A floatable multiparticulate system with potential for intragastric sustained delivery is one of the approaches to get the gastroretention. Cinnarizine(CNZ, an antihistaminic drug used in vertigo caused by meniere’s disease was taken as a model drug for floating beads prepared by non effervescent method. Floating CNZ olive oil-entrapped emulsion gel beads were prepared by the emulsion–gelation method. Different concentrations of sodium alginate (1%, 2%, and 3% w/v, oil (5%, 10%, and 15% v/v, and calcium chloride (0.02, 0.1, and 0.5M were used and their influence on beads uniformity, buoyancy, and in vitro drug release was studied. The results indicated that retardation of drug release was achieved by the oil hydrophobic diffusion barrier, especially in the presence of the compact network of alginate beads. The selected formula of calcium alginate beads using 3% w/v sodium alginate, 15% v/v oil and 0.1 M calcium chloride, showed a higher similarity factor (f2 =70.1 of CNZ release in comparison to release from standard gastroretentive sustained release floating cinnarizine tablet with good floating over duration of more than 12 hours.

  3. The Photocatalytic Activity of Nano-TiO2 (anatase) Gradient Coating on Tourmaline Beads

    International Nuclear Information System (INIS)

    Gradient nano-TiO2(anatase) /tourmaline beads were prepared by sol impregnated method, and the phase composition and microstructure of gradient coating were characterized by XRD and SEM, and the photocatalytic activity were evaluated by degradation of methyl orange (MO), compared with that of pure nano-TiO2 (anatase), tourmaline beads. The result indicated that the MO degradation ratio by tourmaline beads is 5.8%; that by pure nano-TiO2 (anatase) is 38.2%; while the MO degradation ratio approached 70.4% by gradient nano-TiO2 (anatase) /tourmaline beads, much better than the other two types of catalysts. When the gradient nano-TiO2 (anatase) /tourmaline beads are illuminated by UV irradiation, the electron-hole pairs are generated and the photogenerated carrier will be adsorbed tightly on the anode of tourmaline, owing to its strong electrostatic field, which suppresses the recombination of the electron-hole pairs, and enhances photocatalytic efficiency.

  4. A disposable bio-nano-chip using agarose beads for high performance immunoassays.

    Science.gov (United States)

    Du, Nan; Chou, Jie; Kulla, Eliona; Floriano, Pierre N; Christodoulides, Nicolaos; McDevitt, John T

    2011-10-15

    This article reports on the fabrication of a disposable bio-nano-chip (BNC), a microfluidic device composed of polydimethylsiloxane (PDMS) and thiolene-based optical epoxy which is both cost-effective and suitable for high performance immunoassays. A novel room temperature (RT) bonding technique was utilized so as to achieve irreversible covalent bonding between PDMS and thiolene-based epoxy layers, while at the same time being compatible with the insertion of agarose bead sensors, selectively arranged in an array of pyramidal microcavities replicated in the thiolene thin film layer. In the sealed device, the bead-supporting epoxy film is sandwiched between two PDMS layers comprising of fluidic injection and drain channels. The agarose bead sensors used in the device are sensitized with anti-C-reactive protein (CRP) antibody, and a fluorescent sandwich-type immunoassay was run to characterize the performance of this device. Computational fluid dynamics (CFD) was used based on the device specifications to model the bead penetration. Experimental data revealed analyte penetration of the immunocomplex to 100 μm into the 280 μm diameter agarose beads, which correlated well with the simulation. A dose-response curve was obtained and the linear dynamic range of the assay was established over 1 ng/mL to 50 ng/mL with a limit of detection less than 1 ng/mL. PMID:21852104

  5. Flow-orthogonal bead oscillation in a microfluidic chip with a magnetic anisotropic flux-guide array

    DEFF Research Database (Denmark)

    Van Pelt, Stijn; Derks, Roy; Matteucci, Marco; Hansen, Mikkel Fougt; Dietzel, Andreas

    2011-01-01

    A new concept for the manipulation of superparamagnetic beads inside a microfluidic chip is presented in this paper. The concept allows for bead actuation orthogonal to the flow direction inside a microchannel. Basic manipulation functionalities were studied by means of finite element simulations...... polycarbonate and electroforming of nickel flux-guides. Bead velocities up to 450 μm/s were measured in a 75 μm wide channel. By prescribing the currents in the external quadrupole magnet, the shape of the bead trajectory could be controlled....

  6. Kinetics of mercury ions removal from synthetic aqueous solutions using by novel magnetic p(GMA-MMA-EGDMA) beads.

    Science.gov (United States)

    Bayramoğlu, Gülay; Arica, M Yakup

    2007-06-01

    Poly(glycidylmethacrylate-methylmethacrylate), p(GMA-MMA-EGDMA), magnetic beads were prepared via suspension polymerization in the presence of ferric ions. The epoxy groups of the beads were converted into amino groups via ring opening reaction of the ammonia and, the aminated magnetic beads were used for the removal of Hg(II) ions from aqueous solution in a batch experiment and in a magnetically stabilized fluidized bed reactor (MFB). The magnetic p(GMA-MMA-EGDMA) beads were characterized with scanning electron microscope (SEM), FT-IR and ESR spectrophotometers. The optimum removal of Hg(II) ions was observed at pH 5.5. The maximum adsorption capacity of Hg(II) ions by using the magnetic beads was 124.8+/-2.1 mgg(-1) beads. In the continuous MFB reactor, Hg(II) ions adsorption capacity of the magnetic beads decreased with an increase in the flow-rate. The maximum adsorption capacity of the magnetic beads in the MFB reactor was 139.4+/-1.4 mgg(-1). The results indicate that the magnetic beads are promising for use in MFB for removal of Hg(II) ions from aqueous solution and/or waste water treatment. PMID:17118552

  7. Kinetics of mercury ions removal from synthetic aqueous solutions using by novel magnetic p(GMA-MMA-EGDMA) beads

    Energy Technology Data Exchange (ETDEWEB)

    Bayramoglu, Guelay [Biochemical Processing and Biomaterial Research Laboratory, Faculty of Science, Kirikkale University, 71450 Yahsihan, Kirikkale (Turkey)]. E-mail: gbayramoglu@kku.edu.tr; Arica, M. Yakup [Biochemical Processing and Biomaterial Research Laboratory, Faculty of Science, Kirikkale University, 71450 Yahsihan, Kirikkale (Turkey)

    2007-06-01

    Poly(glycidylmethacrylate-methylmethacrylate), p(GMA-MMA-EGDMA), magnetic beads were prepared via suspension polymerization in the presence of ferric ions. The epoxy groups of the beads were converted into amino groups via ring opening reaction of the ammonia and, the aminated magnetic beads were used for the removal of Hg(II) ions from aqueous solution in a batch experiment and in a magnetically stabilized fluidized bed reactor (MFB). The magnetic p(GMA-MMA-EGDMA) beads were characterized with scanning electron microscope (SEM), FT-IR and ESR spectrophotometers. The optimum removal of Hg(II) ions was observed at pH 5.5. The maximum adsorption capacity of Hg(II) ions by using the magnetic beads was 124.8 {+-} 2.1 mg g{sup -1} beads. In the continuous MFB reactor, Hg(II) ions adsorption capacity of the magnetic beads decreased with an increase in the flow-rate. The maximum adsorption capacity of the magnetic beads in the MFB reactor was 139.4 {+-} 1.4 mg g{sup -1}. The results indicate that the magnetic beads are promising for use in MFB for removal of Hg(II) ions from aqueous solution and/or waste water treatment.

  8. Selective extraction of plutonium from nitric acid medium by bifunctional polyethersulfone beads for quantification with thermal ionisation mass spectrometry

    International Nuclear Information System (INIS)

    Polyethersulfone (PES) magnetic beads were prepared by phase inversion technique. The beads were grafted with two monomers, viz. 2-hydroxyethylmethacrylate phosphoric acid (HEMP) and (3-acrylamidopropyl)trimethyl ammonium chloride (AMAC), by photo-induced free radical polymerization. Effect of different HNO3 concentrations on the sorption profiles of Am(III) and Pu(IV) was studied using the grafted PES beads. The beads were found to extract plutonium quantitatively from high nitric acid medium (3-8 M). The effect of presence of competing actinide, e.g. U(VI), on the sorption of Pu(IV) was also studied. (author)

  9. 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. PMID:25149001

  10. Blast Analysis of Laminated Glass Curtain Walls Equipped by Viscoelastic Dissipative Devices

    Directory of Open Access Journals (Sweden)

    Chiara Bedon

    2012-09-01

    Full Text Available Nonlinear numerical simulations are reported for a conventional unitized laminated glass curtain wall subjected to high- and low-level air blast loading. The studied curtain wall, spanning floor to floor, consisted of a laminated glass panel, a continuous bead of structural silicone sealant, a split screw spline frame and four rigid brackets. Firstly, a linear elastic FE-model (M01 is presented to investigate dynamic stresses and deflections due to explosion, by taking into account geometrical nonlinearities. Since, in similar glazing systems, it is important to take into account the possible cracking of glass lites, a second model (M02, calibrated to previous experimental data, is proposed. In it, glass behaves as a brittle-elastic material, whereas an elastoplastic characteristic curve is assumed for mullions. As a result, the design explosion seriously affects the main components of the curtain wall, especially the bead of silicone. To address these criticalities, additional viscoelastic (VE devices are installed at the frame corners (M03. Their effectiveness explains the additional deformability provided to the conventional curtain wall, as well as the obvious dissipation of the incoming energy due to blast loading. Structural and energy capabilities provided by devices are highlighted by means of numerical simulations.

  11. Automatic Wall Painting Robot

    OpenAIRE

    P.KEERTHANAA, K.JEEVITHA, V.NAVINA, G.INDIRA, S.JAYAMANI

    2013-01-01

    The Primary Aim Of The Project Is To Design, Develop And Implement Automatic Wall Painting Robot Which Helps To Achieve Low Cost Painting Equipment. Despite The Advances In Robotics And Its Wide Spreading Applications, Interior Wall Painting Has Shared Little In Research Activities. The Painting Chemicals Can Cause Hazards To The Human Painters Such As Eye And Respiratory System Problems. Also The Nature Of Painting Procedure That Requires Repeated Work And Hand Rising Makes It Boring, Time A...

  12. Plasma-wall interaction

    International Nuclear Information System (INIS)

    This document gathers the 43 slides presented in the framework of the week long lecture 'hot plasmas 2004' and dedicated to plasma-wall interaction in a tokamak. This document is divided into 4 parts: 1) thermal load on the wall, power extraction and particle recovery, 2) basic edge plasma physics, 3) processes that drive the plasma-solid interaction, and 4) material conditioning (surface treatment...) for ITER

  13. Conducting Wall Hall Thrusters

    Science.gov (United States)

    Goebel, Dan M.; Hofer, Richard R.; Mikellides, Ioannis G.; Katz, Ira; Polk, James E.; Dotson, Brandon

    2013-01-01

    A unique configuration of the magnetic field near the wall of Hall thrusters, called Magnetic Shielding, has recently demonstrated the ability to significantly reduce the erosion of the boron nitride (BN) walls and extend the life of Hall thrusters by orders of magnitude. The ability of magnetic shielding to minimize interactions between the plasma and the discharge chamber walls has for the first time enabled the replacement of insulating walls with conducting materials without loss in thruster performance. The boron nitride rings in the 6 kW H6 Hall thruster were replaced with graphite that self-biased to near the anode potential. The thruster efficiency remained over 60% (within two percent of the baseline BN configuration) with a small decrease in thrust and increase in Isp typical of magnetically shielded Hall thrusters. The graphite wall temperatures decreased significantly compared to both shielded and unshielded BN configurations, leading to the potential for higher power operation. Eliminating ceramic walls makes it simpler and less expensive to fabricate a thruster to survive launch loads, and the graphite discharge chamber radiates more efficiently which increases the power capability of the thruster compared to conventional Hall thruster designs.

  14. Development of simple and efficient protocol for isolation of plasmids from mycobacteria using zirconia beads.

    Science.gov (United States)

    Madiraju, M V; Qin, M H; Rajagopalan, M

    2000-01-01

    A two-step protocol has been developed for isolation of plasmids from recombinant mycobacteria via Escherichia coli. First either mycobacterial primary transformants or propagated cultures were lysed in a mini-bead beater using zirconia beads and the lysate thus obtained was used to transform E. coli recA mutant cells. Secondly, plasmid DNA was isolated from recombinant E. coli cells and analysed. Bead beating times of 2 min for Mycobacterium smegmatis, a rapid grower, and 4 min for M. bovis BCG, a slow grower, were found to be optimal for recovery of plasmid DNA. This protocol was also amenable to other mycobacterial species such as M. avium, M. fortuitum and M. tuberculosis H37Ra. Plasmid recovery from the recombinant M. bovis BCG using this protocol is approximately 300-fold higher than that reported for the electroduction method. PMID:10728558

  15. Analysis of early medieval glass beads – Glass in the transition period

    International Nuclear Information System (INIS)

    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.

  16. Co(II) removal by magnetic alginate beads containing Cyanex 272.

    Science.gov (United States)

    Ngomsik, Audrey-Flore; Bee, Agnès; Siaugue, Jean-Michel; Talbot, Delphine; Cabuil, Valérie; Cote, Gérard

    2009-07-30

    In this study, a series of batch experiments is conducted to investigate the ability of magnetic alginate beads containing Cyanex 272 to remove Co(II) ions from aqueous solutions. Equilibrium sorption experiments show a Co(II) uptake capacity of 0.4 mmol g(-1). The data are successfully modelled with a Langmuir equation. A series of kinetics experiments is then carried out and a pseudo-second order equation is used to fit the experimental data. The effect of pH on the sorption of Co(II) ions is also investigated. Desorption experiments by elution of the loaded beads with nitric acid at pH 1 show that the magnetic alginate beads could be reused without significant losses of their initial properties even after 3 adsorption-desorption cycles. PMID:19157703

  17. 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.

  18. Application of RVM for prediction of bead shape in underwater rotating arc welding

    Institute of Scientific and Technical Information of China (English)

    Du Jianhui; Shi Yonghua; Wang Guorong; Huang Guoxing

    2010-01-01

    Bead shape in underwater rotating arc welding was affected by several welding parameters.RVM(relevance vector machine)was used to build a model to predict weld bead shape.The training data set of RVM consists of the welding parameters which are rotational frequency,rotational radius,height of torch and welding current and the features of the bead shape.The maximum error and mean error for prediction of width are 0.10 mm and 0.09 mm,respectively,and the maximum error and mean error for prediction of penetration are 0.31 nun and 0.12 mm,respectively,which are showed that the prediction model can achieve higher prediction precision at reasonably small size of training data set.

  19. 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...... minimal influence of external variables. Three different sensor designs are analyzed theoretically. To experimentally validate the theoretical signals, two sets of measurements are performed. First, the sensor signals are characterized as function of an externally applied magnetic field. Then...... by the sensor self-field or a combination thereof. The sensors can be made nominally insensitive to small external magnetic fields, while being maximally sensitive to magnetic beads, magnetized by the sensor self-field. Thus, the sensor designs can be tailored towards specific applications with...

  20. Exploitation of novel gum Prunus cerasoides as mucoadhesive beads for a controlled-release drug delivery.

    Science.gov (United States)

    Seelan, T Veenus; Kumari, Henry Linda Jeeva; Kishore, Narra; Selvamani, Palanisamy; Lalhlenmawia, H; Thanzami, K; Pachuau, Lalduhsanga; Ruckmani, Kandasamy

    2016-04-01

    The present study deals with the formulation of pH-sensitive mucoadhesive beads using natural gum isolated from Prunus cerasoides (PC) in combination with sodium alginate (SA) for the controlled release of diclofenac sodium (DS). PC and SA composite (PC-SA), DS loaded SA (DS-SA) and DS loaded PC-SA (DS-PC-SA) beads were prepared by ionotropic gelation method. The absence of interaction between DS and PC-SA was shown by FTIR, DSC and TGA analyses. The optimized DS-PC-SA formulation exhibited mucoadhesive property and the controlled release of DS was achieved 68% in 12h. The in vitro release kinetics follows zero order with anomalous diffusion mechanism. Therefore, the formulated mucoadhesive beads with the novel gum are preferable for the controlled release of DS by prolonging the residence time of the drug in the gastrointestinal tract, overcoming the problems associated with the immediate release dosage forms of DS. PMID:26772921

  1. 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. PMID:26454107

  2. 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....

  3. Synthesis and characterization of S-Au interaction in gold nanoparticle bound polymeric beads

    International Nuclear Information System (INIS)

    A detailed X-ray Absorption Spectroscopic examination of S-Au interaction in gold nanoparticle bound to Polystyrene-Divinyl Benzene (PS-DVB) micro beads was carried out. Gold nanoparticles were bound to the surface of the commercially available PS-DVB beads using a simple one step procedure. Influence of polystyrene backbone on the electronic structure of the gold nanoparticles was observed through X-ray Absorption Near Edge Structure (XANES) spectra of Au at L III edge. An additional structure in the white line of the S K-edge XANES spectrum confirmed the presence of S-Au bonding. Transmission Electron Microscopy (TEM) studies coupled with Selected Area Electron Diffraction Pattern and X-ray Diffraction studies revealed the morphology of the Au nanoparticles bound to the micro beads

  4. 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.

  5. Transcatheter Treatment of Hepatocellular Carcinoma with Doxorubicin-loaded DC Bead (DEBDOX): Technical Recommendations

    International Nuclear Information System (INIS)

    Tranarterial chemoembolization (TACE) has been established by a meta-analysis of randomized controlled trials as the standard of care for nonsurgical patients with large or multinodular noninvasive hepatocellular carcinoma (HCC) isolated to the liver and with preserved liver function. Although conventional TACE with administration of an anticancer-in-oil emulsion followed by embolic agents has been the most popular technique, the introduction of embolic drug-eluting beads has provided an alternative to lipiodol-based regimens. Experimental studies have shown that TACE with drug-eluting beads has a safe pharmacokinetic profile and results in effective tumor killing in animal models. Early clinical experiences have confirmed that drug-eluting beads provide a combined ischemic and cytotoxic effect locally with low systemic toxic exposure. Recently, the clinical value of a TACE protocol performed by using the embolic microsphere DC Bead loaded with doxorubicin (DEBDOX; drug-eluting bead doxorubicin) has been shown by randomized controlled trials. An important limitation of conventional TACE has been the inconsistency in the technique and the treatment schedules. This limitation has hampered the acceptance of TACE as a standard oncology treatment. Doxorubicin-loaded DC Bead provides levels of consistency and repeatability not available with conventional TACE and offers the opportunity to implement a standardized approach to HCC treatment. With this in mind, a panel of physicians took part in a consensus meeting held during the European Conference on Interventional Oncology in Florence, Italy, to develop a set of technical recommendations for the use of DEBDOX in HCC treatment. The conclusions of the expert panel are summarized.

  6. Characterization of gliclazide release from Isabgol husk hydrogel beads by validated HPLC method.

    Science.gov (United States)

    Sharma, Vipin K; Mazumdar, B

    2014-01-01

    Isabgol husk, a medicinally important natural polysaccharide was applied for fabrication of hydrogel beads by ionic gelation method to incorporate gliclazide. Different strengths of Isabgol husk and sodium alginate were utilized for assessing the process variables on formulation performance. Aqueous solution of calcium chloride in 2, 5 and 8% w/v strength was used as cross-linker for polymeric blends of Isabgol husk and sodium alginate. The formulations were characterized for various parameters such as particle size, swelling index, entrapment efficiency, in vitro release, and release kinetics. The quantification of gliclazide throughout the study was performed by HPLC method which was validated according to ICH guidelines for system suitability, linearity, accuracy, sensitivity, precession, robustness, and ruggedness. The surface morphology of beads was observed by scanning electron microscopy. The formed beads were brown, free flowing, spherical, and irregular in structure. The size in different formulations varied from 752.83 +/- 0.630 to 838.62 +/- 0.741 microm. The beads remained for 2-3 h in alkaline phosphate buffer (pH 7.4), after that they showed disintegration. The formulations released up to 95% of loaded gliclazide in phosphate buffer (pH 7.4) within 8 h. No significant difference was observed in parameters studied such as particle size, entrapment efficiency and swelling index for hydrogel beads during accelerated stability study (p > 0.05). The regression equation developed by HPLC method was linear (r5 > 0.9990) over the range 2.5 to 10 microg/mL. The limit of detection (LOD) and limit of quantification (LOQ) were 0.037619 microg/mL and 0.113997 microg/mL, respectively. The observed values for number of theoretical plates (N > or = 2000), tailing factor (T gliclazide estimation in Isabgol husk hydrogel beads. PMID:24779204

  7. Encapsulated human hepatocellular carcinoma cells by alginate gel beads as an in vitro metastasis model

    International Nuclear Information System (INIS)

    Hepatocellular carcinoma (HCC) is the most common primary liver cancer and often forms metastases, which are the most important prognostic factors. For further elucidation of the mechanism underlying the progression and metastasis of HCC, a culture system mimicking the in vivo tumor microenvironment is needed. In this study, we investigated the metastatic ability of HCC cells cultured within alginate gel (ALG) beads. In the culture system, HCC cells formed spheroids by proliferation and maintained in nuclear abnormalities. The gene and protein expression of metastasis-related molecules was increased in ALG beads, compared with the traditional adhesion culture. Furthermore, several gene expression levels in ALG bead culture system were even closer to liver cancer tissues. More importantly, in vitro invasion assay showed that the invasion cells derived from ALG beads was 7.8-fold higher than adhesion cells. Our results indicated that the in vitro three-dimensional (3D) model based on ALG beads increased metastatic ability compared with adhesion culture, even partly mimicked the in vivo tumor tissues. Moreover, due to the controllable preparation conditions, steady characteristics and production at large-scale, the 3D ALG bead model would become an important tool used in the high-throughput screening of anti-metastasis drugs and the metastatic mechanism research. -- Highlights: •We established a 3D metastasis model mimicking the metastatic ability in vivo. •The invasion ability of cells derived from our model was increased significantly. •The model is easy to reproduce, convenient to handle, and amenable for large-scale

  8. Transcatheter Treatment of Hepatocellular Carcinoma with Doxorubicin-loaded DC Bead (DEBDOX): Technical Recommendations

    Energy Technology Data Exchange (ETDEWEB)

    Lencioni, Riccardo, E-mail: riccardo.lencioni@med.unipi.it [Pisa University Hospital, University of Pisa, Division of Diagnostic Imaging and Intervention (Italy); Baere, Thierry de [Institut Gustav-Roussy, Department of Interventional Radiology (France); Burrel, Marta [Barcelona Clinic for Liver Cancer, Hospital Clinic, Department of Radiology (Spain); Caridi, James G. [University of Florida, Division of Interventional Radiology (United States); Lammer, Johannes [Medical University of Vienna, Department of Interventional Radiology (Austria); Malagari, Katerina [University of Athens, Department of Radiology (Greece); Martin, Robert C. G. [University of Louisville, Division of Surgical Oncology (United States); O' Grady, Elizabeth [University Hospital Aintree, Department of Radiology (United Kingdom); Real, Maria Isabel [Barcelona Clinic for Liver Cancer, Hospital Clinic, Department of Radiology (Spain); Vogl, Thomas J. [University of Frankfurt, Department of Radiology (Germany); Watkinson, Anthony [Royal Devon and Exeter Hospital, Department of Interventional Radiology (United Kingdom); Geschwind, Jean-Francois H. [Johns Hopkins University, Division of Interventional Radiology (United States)

    2012-10-15

    Tranarterial chemoembolization (TACE) has been established by a meta-analysis of randomized controlled trials as the standard of care for nonsurgical patients with large or multinodular noninvasive hepatocellular carcinoma (HCC) isolated to the liver and with preserved liver function. Although conventional TACE with administration of an anticancer-in-oil emulsion followed by embolic agents has been the most popular technique, the introduction of embolic drug-eluting beads has provided an alternative to lipiodol-based regimens. Experimental studies have shown that TACE with drug-eluting beads has a safe pharmacokinetic profile and results in effective tumor killing in animal models. Early clinical experiences have confirmed that drug-eluting beads provide a combined ischemic and cytotoxic effect locally with low systemic toxic exposure. Recently, the clinical value of a TACE protocol performed by using the embolic microsphere DC Bead loaded with doxorubicin (DEBDOX; drug-eluting bead doxorubicin) has been shown by randomized controlled trials. An important limitation of conventional TACE has been the inconsistency in the technique and the treatment schedules. This limitation has hampered the acceptance of TACE as a standard oncology treatment. Doxorubicin-loaded DC Bead provides levels of consistency and repeatability not available with conventional TACE and offers the opportunity to implement a standardized approach to HCC treatment. With this in mind, a panel of physicians took part in a consensus meeting held during the European Conference on Interventional Oncology in Florence, Italy, to develop a set of technical recommendations for the use of DEBDOX in HCC treatment. The conclusions of the expert panel are summarized.

  9. Electro-spray of high viscous liquids for producing mono-sized spherical alginate beads

    Institute of Scientific and Technical Information of China (English)

    Hamid Moghadam; Mohsen Samimi; Abdolreza Samimi; Mohamad Khorram

    2008-01-01

    Alginate beads, often used for controlled release of enzymes and drugs, are usually produced by spraying sodium alginate liquid into a gelling agent using mechanical vibration nozzle or air jet. In this work an alternative method of electro-spray was employed to form droplets with desired size from a highly viscous sodium alginate solution using constant DC voltage. The droplets were then cured in a calcium chloride solution. The main objective was to produce mono-sized beads from such a highly viscous and non-Newtonian liquid (1000-5000 mPa s). The effects of nozzle diameter, flow rate and concentration of liquid on the size of the beads were investigated. Among the parameters studied, voltage had a pronounced effect on the size of beads as compared to flow rate zzle diameter and concentration of alginate liquid. The size of beads was reduced to a minimum value with increasing the voltage in the range of 0-10 kV. At the early stages of voltage increase (I.e. Up to about 4 kV), the rate of size reduction was relatively low, while the dripping mode dominated. However, in the middle part of the range of applied voltage, where the rate of size reduction was high (I.e. About 4-7 kV), an unstable transition occurred between dripping and jetting. At the end part of the range (I.e. 7-10 kV) jet mode of spray was observed. Increasing the height of fall of the droplets was found to improve the sphericity of the beads, because of the increased time of flight for the droplets. This was especially identifiable at higher concentrations of the alginate liquid (I.e. 3 w/v%)

  10. Study on the uptake of Americium using PC88A - impregnated macroporous polymeric beads

    International Nuclear Information System (INIS)

    The prime objective of radioactive waste treatment in nuclear industry is to minimize the waste volume by efficient process without generating secondary radioactive waste for its final disposal. Among the currently available technologies, for separation and recovery of metal ions, solvent extraction, ion-exchange, membrane based technologies and solid sorbent materials are more popular means. Though, all these technologies play major role in all the bulk separation processes, their marked limitations force the separation scientists to think of advance, more efficient and technically feasible alternatives. The extractant impregnated polymeric beads (EIMPBs), impregnated with metal-specific extractants, exhibit reliable separation performances under column operation, and hence bridge the gap between solvent extraction and ion exchange techniques. In the present work, PC88A impregnated PES beads are prepared and the sorption of Am (III) from aqueous waste solutions is investigated. The synthesized EIMPBs were characterized by FTIR, TGA and SEM techniques. The physiochemical strength of the beads was found to be excellent. The sorption study of Am (III), using these beads, was carried out by batch equilibration method and the effect of various parameters, like pH, equilibration time, Am (III) concentration, etc., on the sorption process, was investigated. The synthesized polymeric beads presented fairly higher sorption capacity for Am (III) at pH 3. The kinetics of extraction is very fast. The saturation of sorption is achieved in about 60 minutes of equilibration. The sorption kinetics data fits well in the pseudo second-order model, indicating that the sorption is dominated by chemisorptions. The sorption of Am (III) is observed to follow Langmuir isotherm and the monolayer capacity was calculated as 2.498 mg/g. The quantitative stripping of the extracted Am (III) can be achieved by using 0.1M oxalic acid. The blank polymeric beads, without PC88A,have shown

  11. Single-bead arrays for fluorescence-based immunoassays on capillary-driven microfluidic chips

    Science.gov (United States)

    Temiz, Yuksel; Lim, Michel; Delamarche, Emmanuel

    2016-03-01

    We report a concept for the simple fabrication of easy-to-use chips for immunoassays in the context of point-of-care diagnostics. The chip concept comprises mainly three features: (1) the efficient integration of reagents using beads functionalized with receptors, (2) the generation of capillary-driven liquid flows without using external pumps, and (3) a high-sensitivity detection of analytes using fluorescence microscopy. We fabricated prototype chips using dry etching of Si wafers. 4.5-μm-diameter beads were integrated into hexagonal arrays by sedimentation and removing the excess using a stream of water. We studied the effect of different parameters and showed that array occupancies from 30% to 50% can be achieved by pipetting a 250 nL droplet of 1% bead solution and allowing the beads sediment for 3 min. Chips with integrated beads were sealed using a 50-μm-thick dry-film resist laminated at 45 °C. Liquids pipetted to loading pads were autonomously pulled by capillary pumps at a rate of 0.35 nL s-1 for about 30 min. We studied ligand-receptor interactions and binding kinetics using time-lapse fluorescence microscopy and demonstrated a 5 pM limit of detection (LOD) for an anti-biotin immunoassay. As a clinically-relevant example, we implemented an immunoassay to detect prostate specific antigen (PSA) and showed an LOD of 108 fM (i.e. 3.6 pg mL-1). While a specific implementation is provided here for the detection of PSA, we believe that combining capillary-driven microfluidics with arrays of single beads and fluorescence readout to be very flexible and sufficiently sensitive for the detection of other clinically-relevant analytes.

  12. Magnetic bead-quantum dot assay for detection of a biomarker for traumatic brain injury

    Science.gov (United States)

    Kim, Chloe; Searson, Peter C.

    2015-10-01

    Current diagnostic methods for traumatic brain injury (TBI), which accounts for 15% of all emergency room visits, are limited to neuroimaging modalities. The challenges of accurate diagnosis and monitoring of TBI have created the need for a simple and sensitive blood test to detect brain-specific biomarkers. Here we report on an assay for detection of S100B, a putative biomarker for TBI, using antibody-conjugated magnetic beads for capture of the protein, and antibody-conjugated quantum dots for optical detection. From Western Blot, we show efficient antigen capture and concentration by the magnetic beads. Using magnetic bead capture and quantum dot detection in serum samples, we show a wide detection range and detection limit below the clinical cut-off level.Current diagnostic methods for traumatic brain injury (TBI), which accounts for 15% of all emergency room visits, are limited to neuroimaging modalities. The challenges of accurate diagnosis and monitoring of TBI have created the need for a simple and sensitive blood test to detect brain-specific biomarkers. Here we report on an assay for detection of S100B, a putative biomarker for TBI, using antibody-conjugated magnetic beads for capture of the protein, and antibody-conjugated quantum dots for optical detection. From Western Blot, we show efficient antigen capture and concentration by the magnetic beads. Using magnetic bead capture and quantum dot detection in serum samples, we show a wide detection range and detection limit below the clinical cut-off level. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr05608j

  13. Development and validation of predictive simulation model of multi-layer repair welding process by temper bead technique

    International Nuclear Information System (INIS)

    Stress corrosion cracking (SCC) has recently been observed in the nickel base alloy weld metal of dissimilar pipe joint used in pressurized water reactor (PWR) . Temper bead technique has been developed as one of repair procedures against SCC applicable in case that post weld heat treatment (PWHT) is difficult to carry out. In this regard, however it is essential to pass the property and performance qualification test to confirm the effect of tempering on the mechanical properties at repair welds before temper bead technique is actually used in practice. Thus the appropriate welding procedure conditions in temper bead technique are determined on the basis of the property and performance qualification testing. It is necessary for certifying the structural soundness and reliability at repair welds but takes a lot of work and time in the present circumstances. Therefore it is desirable to establish the reasonable alternatives for qualifying the property and performance at repair welds. In this study, mathematical modeling and numerical simulation procedures were developed for predicting weld bead configuration and temperature distribution during multi-layer repair welding process by temper bead technique. In the developed simulation technique, characteristics of heat source in temper bead welding are calculated from weld heat input conditions through the arc plasma simulation and then weld bead configuration and temperature distribution during temper bead welding are calculated from characteristics of heat source obtained through the coupling analysis between bead surface shape and thermal conduction. The simulation results were compared with the experimental results under the same welding heat input conditions. As the results, the bead surface shape and temperature distribution, such as Acl lines, were in good agreement between simulation and experimental results. It was concluded that the developed simulation technique has the potential to become useful for accurate

  14. Fibroblast receptor for cell-substratum adhesion: studies on the interaction of baby hamster kidney cells with latex beads coated by cold insoluble globulin (plasma fibronectin)

    OpenAIRE

    1980-01-01

    Studies were carried out on the interactions of uncharged latex beads (0.76 micrometer) with baby hamster kidney cells. Binding of beads to the cells occurred if the beads were coated by cold insoluble globulin (CIG) (plasma fibronectin) but not if the beads were coated by bovine albumin. Bovine albumin-coated beads did not bind to the cells even in the presence of excess CIG in the incubation medium. Binding of beads occurred randomly over the entire surfaces of cells in suspension. However,...

  15. Mössbauer evaluation of the interparticle magnetic Interactions within the magnetic hyperthermia beads

    International Nuclear Information System (INIS)

    Mössbauer spectroscopy was used for direct experimental measurement of the Néel barrier height for magnetization reversal in ensembles of interacting γ-Fe2O3 nanoparticles. As the barrier height is proportional to the size of the magnetic cluster, these measurements enable an evaluation of the relative sizes of the magnetically coupled clusters that are formed during the manufacture of the magnetic hyperthermia beads. For the hyperthermia beads, which were synthesized and studied in the work, an increase in the size of the magnetically coupled cluster corresponds to a reduction of the specific loss power

  16. A Novel Magnetic Bead-based Biosensor Using Flip Chip Bonding Techniques

    Institute of Scientific and Technical Information of China (English)

    Bin Wang; Xiang Chen; Qinghui Jin; Jianlong Zhao; Yuansen Xu

    2006-01-01

    Based on flip-chip packaging, a novel approach towards integrated magnetic bio-separator was designed. The magnetic field and the force on the bead were simulated and analyzed, leading to the optimization of the fabrication parameters of the micro-magnetic unit. The planar coil as an electromagnet was fabricated through electroplating on a single seed layer.The PDMS microfluidic channel was bonded on the inverse side after Si etching. The results presented in this paper provide a novel design and fabrication to approach a microfluidic bio-separation system with magnetic beads.

  17. 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.

  18. ADSORPTION OF Mg(II) ION FROM AQUEOUS SOLUTION ON CHITOSAN BEADS AND CHITOSAN POWDER

    OpenAIRE

    Sari Edi Cahyaningrum

    2010-01-01

    A basic investigation on the removal of Mg(II) ion from aqueous solution by chitosan beads wasconducted in a batch adsorption system. The influence of different experimental parameters; pH,agitation period and different concentration of Mg(II) ion was evaluated. A pH 7.0 was found to be anoptimum pH for Mg(II) adsorption onto chitosan powder and chitosan beads. The Langmuir andFreundlich adsorption isotherm models were applied to describe the isotherms and isotherm constantsfor the adsorption...

  19. Removal of hexavalent chromium from aqueous solution by barium ion cross-linked alginate beads

    OpenAIRE

    Uzaşçı Sesil; Tezcan Filiz; Bedia Erim F.

    2014-01-01

    Barium ion cross-linked alginate beads have shown great affinity to toxic hexavalent chromium ions in aqueous solution, contrary to the traditional calcium alginate beads. The adsorption experiments were carried out by the batch contact method. The optimal pH for removal was found to be pH 4. The equilibrium was established in 4 h and the removal efficiency of chromium (VI) was found as 95%. The adsorption data fit well with Langmuir and Freundlich isotherms. The maximum chromium (VI) adsorpt...

  20. Study of Spatio-Temporal Immunofluorescence on Bead Patterns in a Microfluidic Channel

    Science.gov (United States)

    Sivagnanam, Venkataragavalu; Yang, Hui; Gijs, Martin A. M.

    2010-12-01

    We performed a direct immunoassay inside a microfluidic channel on patterned streptavidin-coated beads, which captured fluorescently-labeled biotin target molecules from a continuous flow. We arranged the beads in a dot array at the bottom of the channel and demonstrated their position- and flow rate-dependent fluorescence. As the target analyte gets gradually depleted from the flow when passing downstream the channel, the highest fluorescence intensity was observed on the most upstream positioned dot patterns. We propose a simple analytical convection model to explain this spatio-temporal fluorescence.

  1. 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

    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 for...

  2. Dependence of effective screening length in granular columns on bead and silo sizes and their ratio

    Institute of Scientific and Technical Information of China (English)

    Abdul Qadir; Madad Ali Shah; Saeed Ahmed Khan

    2013-01-01

    Apparent mass measurements at the bottom of silos have been carried out.An important parameter in the Janssen model known as the effective screening length has been investigated for different bead and silo diameters as well as of their ratios.It is found that the effective screening length augments with the grain diameter d in addition to the granular column size.It is also revealed that λ exhibits stronger correlation with the bead diameter than that of the silo.This phenomenon is attributed to the reduced-shielding of the vertical stresses to the horizontal ones.

  3. Development of resin-bead isotope-dilution mass spectrometric techniques for Tc-99 analysis

    International Nuclear Information System (INIS)

    An isotope dilution mass spectrometric method was developed for the analysis of Tc-99 after isolating it onto anion exchange resin beads. A single resin bead containing Tc-99 and Tc-97 spike is loaded onto a rhenium V-shaped filament for thermal emission mass spectrometry. The application of this technique requires the use of a mass spectrometer of high abundance sensitivity and pulse counting capability for the necessary ion detection sensitivity. This paper discusses the development of the technique, including the mass spectrometer, choice of filament material, scanning modes, interferences, and present achievable sample sensitivities

  4. Factors Influencing the Nitrification Efficiency of Fluidized Bed Filters With a Plastic Bead Medium

    OpenAIRE

    Sandu, Simonel Ioan

    2000-01-01

    Nitrification performance of three, fluidized-bed filters was investigated. Each filter contained 10 L of plastic bead medium (near neutral specific gravity and 2-4 mm diameter and length) and was loaded under conditions of various flow rates and ammonia levels. Bead settled depth and biofilter diameter (12.7, 15.2 and 17.8 cm) were the factors differing among the filters. The experiments were conducted with three replicate recirculating systems. Each system included one of the three differen...

  5. The Numerical Welding Simulation - Developments and Validation of Simplified and Bead Lumping Methods

    International Nuclear Information System (INIS)

    The aim of this work was to study the TIG multipass welding process on stainless steel, by means of numerical methods and then to work out simplified and bead lumping methods in order to reduce adjusting and realisation times of these calculations. A simulation was used as reference for the validation of these methods; after the presentation of the test series having led to the option choices of this calculation (2D generalised plane strains, elastoplastic model with an isotropic hardening, hardening restoration due to high temperatures), various simplifications were tried on a plate geometry. These simplifications related various modelling points with a correct plastic flow representation in the plate. The use of a reduced number of thermal fields characterising the bead deposit and a low number of tensile curves allow to obtain interesting results, decreasing significantly the Computing times. In addition various lumping bead methods have been studied and concerning both the shape and the thermic of the macro-deposits. The macro-deposit shapes studied are in 'L', or in layer or they represent two beads one on top of the other. Among these three methods, only those using a few number of lumping beads gave bad results since thermo-mechanical history was deeply modified near and inside the weld. Thereafter, simplified methods have been applied to a tubular geometry. On this new geometry, experimental measurements were made during welding, which allow a validation of the reference calculation. Simplified and reference calculations gave approximately the same stress fields as found on plate geometry. Finally, in the last part of this document a procedure for automatic data setting permitting to reduce significantly the calculation phase preparation is presented. It has been applied to the calculation of thick pipe welding in 90 beads; the results are compared with a simplified simulation realised by Framatome and with experimental measurements. A bead by

  6. Preparation of Immuno-magnetic Beads and Their Separation & Detection to Ovary Cancer Cells

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The organic monomer-molecule with nanometer magnetic powder by means of reforming the surface of nanometer magnetic powder have been synthesized.Magnetic beads in diameter of 2μm or so are obtained by controlling conditions.Ovary cancer cells of ascites are separated and ovary cancer cells of blood are detected by using immuno-magnetic beads linked with ovary cancer cell mono-antibodies.Results show that the specificity is 85%,sensitivity is 87%,accuracy is 84%,cells acquiring purity is 90%,cells activity is 92% and detection sensitivity is 25×10-7.

  7. Newtonian and non-newtonian low Re number flow through bead packings

    Energy Technology Data Exchange (ETDEWEB)

    Mertens, D.; Hardy, E.H.; Buggisch, H.W. [Institut fuer Mechanische Verfahrenstechnik und Mechanik, Universitaet Karlsruhe (T.H.) (Germany); Heinen, C. [Mechanical Engineering Department, Universite de Sherbrooke (Canada)

    2006-07-15

    The results of measurements of velocity distributions of Newtonian and non-Newtonian fluids flowing through porous media are described in this contribution. The porous matrix was modeled by glass beads of different diameters forming a random bead packing confined by a circular tube. These packings were passed through by aqueous solutions of glucose and xanthane gum. Nuclear magnetic resonance (NMR) methods were applied to investigate the flow field in the packing. Spatially resolved and integral displacement distribution measurements were reported. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  8. The Chlamydomonas cell wall: characterization of the wall framework

    OpenAIRE

    1985-01-01

    The cell wall of the biflagellate alga Chlamydomonas reinhardtii is a multilayered, extracellular matrix composed of carbohydrates and 20-25 polypeptides. To learn more about the forces responsible for the integrity of this cellulose-deficient cell wall, we have begun studies to identify and characterize the framework of the wall and to determine the effects of the cell wall-degrading enzyme, lysin, on framework structure and protein composition. In these studies we used walls released into t...

  9. Lipase in biphasic alginate beads as a biocatalyst for esterification of butyric acid and butanol in aqueous media.

    Science.gov (United States)

    Ng, Choong Hey; Yang, Kun-Lin

    2016-01-01

    Esterification of organic acids and alcohols in aqueous media is very inefficient due to thermodynamic constraints. However, fermentation processes used to produce organic acids and alcohols are often conducted in aqueous media. To produce esters in aqueous media, biphasic alginate beads with immobilized lipase are developed for in situ esterification of butanol and butyric acid. The biphasic beads contain a solid matrix of calcium alginate and hexadecane together with 5 mg/mL of lipase as the biocatalyst. Hexadecane in the biphasic beads serves as an organic phase to facilitate the esterification reaction. Under optimized conditions, the beads are able to catalyze the production of 0.16 mmol of butyl butyrate from 0.5 mmol of butyric acid and 1.5 mmol of butanol. In contrast, when monophasic beads (without hexadecane) are used, only trace amount of butyl butyrate is produced. One main application of biphasic beads is in simultaneous fermentation and esterification (SFE) because the organic phase inside the beads is very stable and does not leach out into the culture medium. SFE is successfully conducted with an esterification yield of 6.32% using biphasic beads containing iso-octane even though the solvent is proven toxic to the butanol-producing Clostridium spp. PMID:26672465

  10. Analysis of in vitro lymphocyte adhesion and transendothelial migration by fluorescent-beads-based flow cytometric cell counting

    NARCIS (Netherlands)

    Molema, Ingrid; Mesander, G; Kroesen, Bart-Jan; Helfrich, Wijnand; Meijer, D.K F; de Leij, Lou

    1998-01-01

    In this report, we describe a new and simple method for flow cytometric quantitation of lymphocyte numbers in lymphocute-endothelial adhesion/transendothelial migration assays. The method exploits fluorescent flow cytometer alignment beads as a counting reference. Known amounts of beads are added to

  11. Resin bead U and PU analysis of WAK input solutions: a statistical summary of experiment No. 1

    International Nuclear Information System (INIS)

    A statistical analysis of the resin bead experimental data was made to identify sources of variations among the measurements of isotopic atom ratios and elemental concentrations of plutonium and uranium. Comparisons among treatment means of the analytical laboratory and the resin bead preparation methods are tabulated using Duncan's multiple range test

  12. 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. PMID:25660257

  13. 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

    modification of the imprinted polymer beads, we also show that the dithioester end groups on the surface of the polymer beads can be converted into new thiol groups without sacrificing the specific molecular recognition. Through the new terminal thiol groups, a fluorescent dye was conveniently conjugated to...

  14. Axion domain wall baryogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Daido, Ryuji; Kitajima, Naoya [Department of Physics, Tohoku University,Sendai 980-8578 (Japan); Takahashi, Fuminobu [Department of Physics, Tohoku University,Sendai 980-8578 (Japan); Kavli IPMU, TODIAS, University of Tokyo,Kashiwa 277-8583 (Japan)

    2015-07-28

    We propose a new scenario of baryogenesis, in which annihilation of axion domain walls generates a sizable baryon asymmetry. Successful baryogenesis is possible for a wide range of the axion mass and decay constant, m≃10{sup 8}–10{sup 13} GeV and f≃10{sup 13}–10{sup 16} GeV. Baryonic isocurvature perturbations are significantly suppressed in our model, in contrast to various spontaneous baryogenesis scenarios in the slow-roll regime. In particular, the axion domain wall baryogenesis is consistent with high-scale inflation which generates a large tensor-to-scalar ratio within the reach of future CMB B-mode experiments. We also discuss the gravitational waves produced by the domain wall annihilation and its implications for the future gravitational wave experiments.

  15. Diffusion of Oligonucleotides from within Iron-Crosslinked Polyelectrolyte-Modified Alginate Beads: A Model System for Drug Release

    CERN Document Server

    Privman, Vladimir; Luz, Roberto A S; Guz, Nataliia; Glasser, M Lawrence; Katz, Evgeny

    2016-01-01

    We developed and experimentally verified an analytical model to describe diffusion of oligonucleotides from stable hydrogel beads. The synthesized alginate beads are Fe3+-cross-linked as well as polyelectrolyte-doped for uniformity and stability at physiological pH. Data on diffusion of oligonucleotides from inside the beads provide physical insights into the volume nature of the immobilization of a fraction of oligonucleotides due to polyelectrolyte cross-linking, i.e., the absence of the surface-layer barrier in this case. Furthermore, our results suggest a new simple approach to measuring the diffusion coefficient of the mobile oligonucleotide molecules inside hydrogel. The considered alginate beads provide a model for a well-defined component in drug release systems and for the oligonucleotide-release transduction steps in drug-delivering and biocomputing applications. This is illustrated by destabilizing the beads with citrate that induces full oligonucleotide release with non-diffusional kinetics.

  16. Diffusion of Oligonucleotides from within Iron-Cross-Linked, Polyelectrolyte-Modified Alginate Beads: A Model System for Drug Release.

    Science.gov (United States)

    Privman, Vladimir; Domanskyi, Sergii; Luz, Roberto A S; Guz, Nataliia; Glasser, M Lawrence; Katz, Evgeny

    2016-04-01

    An analytical model to describe diffusion of oligonucleotides from stable hydrogel beads is developed and experimentally verified. The synthesized alginate beads are Fe(3+) -cross-linked and polyelectrolyte-doped for uniformity and stability at physiological pH. Data on diffusion of oligonucleotides from inside the beads provide physical insights into the volume nature of the immobilization of a fraction of oligonucleotides due to polyelectrolyte cross-linking, that is, the absence of a surface-layer barrier in this case. Furthermore, the results suggest a new simple approach to measuring the diffusion coefficient of mobile oligonucleotide molecules inside hydrogels. The considered alginate beads provide a model for a well-defined component in drug-release systems and for the oligonucleotide-release transduction steps in drug-delivering and biocomputing applications. This is illustrated by destabilizing the beads with citrate, which induces full oligonucleotide release with nondiffusional kinetics. PMID:26762598

  17. HYDROGEL TRACER BEADS: THE DEVELOPMENT, MODIFICATION, AND TESTING OF AN INNOVATIVE TRACER FOR BETTER UNDERSTANDING LNAPL TRANSPORT IN KARST AQUIFERS

    Energy Technology Data Exchange (ETDEWEB)

    Amanda Laskoskie, Harry M. Edenborn, and Dorothy J. Vesper

    2012-01-01

    The goal of this specific research task is to develop proxy tracers that mimic contaminant movement to better understand and predict contaminant fate and transport in karst aquifers. Hydrogel tracer beads are transported as a separate phase than water and can used as a proxy tracer to mimic the transport of non-aqueous phase liquids (NAPL). They can be constructed with different densities, sizes & chemical attributes. This poster describes the creation and optimization of the beads and the field testing of buoyant beads, including sampling, tracer analysis, and quantitative analysis. The buoyant beads are transported ahead of the dissolved solutes, suggesting that light NAPL (LNAPL) transport in karst may occur faster than predicted from traditional tracing techniques. The hydrogel beads were successful in illustrating this enhanced transport.

  18. Double wall underground storage tank

    Energy Technology Data Exchange (ETDEWEB)

    Canaan, E.B. Jr.; Wiegand, J.R.; Bartlow, D.H.

    1993-07-06

    A double wall underground storage tank is described comprising: (a) a cylindrical inner wall, (b) a cylindrical outer wall comprising plastic resin and reinforcement fibers, and (c) a layer of spacer filaments wound around the inner wall, the spacer filaments separating the inner and outer walls, and the spacer filaments being at least partially surrounded by voids to enable liquids to flow along the filaments.

  19. Back Reaction from Walls

    CERN Document Server

    Di Dio, Enea; Durrer, Ruth

    2011-01-01

    We study the distance-redshift relation in a universe filled with 'walls' of pressure-less dust separated by under dense regions. We show that as long as the density contrast of the walls is small, or the diameter of the under dense regions is much smaller than the Hubble scale, the distance-redshift relation remains close to what is obtained in a Friedmann universe. However, when arbitrary density contrasts are allowed, every prescribed distance-redshift relation can be reproduced with such models.

  20. Occupy Wall Street

    DEFF Research Database (Denmark)

    Jensen, Michael J.; Bang, Henrik

    2013-01-01

    This article analyzes the political form of Occupy Wall Street on Twitter. Drawing on evidence contained within the profiles of over 50,000 Twitter users, political identities of participants are characterized using natural language processing. The results find evidence of a traditional oppositio......This article analyzes the political form of Occupy Wall Street on Twitter. Drawing on evidence contained within the profiles of over 50,000 Twitter users, political identities of participants are characterized using natural language processing. The results find evidence of a traditional...

  1. UWB Propagation through Walls

    Directory of Open Access Journals (Sweden)

    M. Hajek

    2006-04-01

    Full Text Available The propagation of ultra wide band (UWB signals through walls is analyzed. For this propagation studies, it is necessary to consider not only propagation at a single frequency but in the whole band. The UWB radar output signal is formed by both transmitter and antenna. The effects of antenna receiving and transmitting responses for various antenna types (such as small and aperture antennas are studied in the frequency as well as time domain. Moreover, UWB radar output signals can be substantially affected due to electromagnetic wave propagation through walls and multipath effects.

  2. Side-wall sampler

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, B.

    1969-11-01

    A side-wall sampler which is capable of taking samples from the walls of test holes to a depth of 1,000 ft or more is described. Samples have been extracted from till, clay, silt, and fine- to coarse-grained sands in drift and nonindurated bedrock from more than 1,000 test holes in S. Saskatchewan. Side-hole sampling is faster and cheaper than conventional sampling methods and is ideally suited for geological investigations. Mineralogical paleonto- locical and radiocarbon analyses have been determined on side-hole cores.

  3. Enhanced biocatalytic esterification with lipase-immobilized chitosan/graphene oxide beads.

    Science.gov (United States)

    Lau, Siaw Cheng; Lim, Hong Ngee; Basri, Mahiran; Fard Masoumi, Hamid Reza; Ahmad Tajudin, Asilah; Huang, Nay Ming; Pandikumar, Alagarsamy; Chia, Chin Hua; Chia, Chi Hua; Andou, Yoshito

    2014-01-01

    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. PMID:25127038

  4. 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.

  5. Use of magnetic beads for tissue DNA extraction and IS6110 Mycobacterium tuberculosis PCR.

    Science.gov (United States)

    Caldarelli-Stefano, R; Vago, L; Bonetto, S; Nebuloni, M; Costanzi, G

    1999-01-01

    Polymerase chain reaction (PCR) techniques are used increasingly for the diagnosis of Mycobacterium tuberculosis infection and can be used on the DNA obtained from both frozen and formalin fixed, paraffin wax embedded tissues. However, the extraction of DNA by means of the conventional phenol/chloroform method is time consuming and requires the use of potentially dangerous chemical reagents. This paper describes a method based upon the use of magnetic beads for the extraction of M tuberculosis DNA from both routinely formalin fixed, paraffin wax embedded tissues and frozen tissues. Magnetic bead extracted DNA from brain, lymph node, and lung tissues collected from patients with human immunodeficiency virus and tuberculosis was compared with that extracted using the phenol/chloroform method. The magnetic bead extraction procedure requires less than two hours, including the time necessary to dewax the tissue sections. In all cases, the DNA extracted with both methods was amplified successfully by PCR for the M tuberculosis IS6110 sequence. Magnetic bead DNA extraction can be used on both frozen and archival tissues: the method is reliable, simple, sensitive, and rapid; in addition, it does not use hazardous procedures or specialised laboratory equipment and can be used for routine DNA isolation from various human tissues. PMID:10621838

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

    Czech Academy of Sciences Publication Activity Database

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

    2016-01-01

    Roč. 132, July (2016), s. 405-414. ISSN 0038-092X R&D Projects: GA MŠk(CZ) LH14318 Institutional support: RVO:61389013 Keywords : latent heat storage * phase change materials * porous beads by suspension polymerization Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.469, year: 2014

  7. Gel-Bead Delivery of Eimeria Oocysts Protects Chickens Against Coccidiosis

    Science.gov (United States)

    Vaccines composed of either virulent or attenuated Eimeria spp. oocysts have been developed as an alternative to medication of feed with ionophore drugs or synthetic chemicals. The purpose of this study was to evaluate the use of gel beads containing a mixture of E. acervulina, E. maxima, and E. te...

  8. Biosorption of radiostrontium by alginate beads. Application of isotherm models and thermodynamic studies

    International Nuclear Information System (INIS)

    Radioactive strontium is one of the major radioactive contaminant and its contamination is a very serious concern. Therefore, there is a need for economic, effective, non-toxic, readily available and abundant adsorbent or biosorbent to remove strontium from solutions. In this study, biosorption of 85Sr as a surrogate for 90Sr onto alginate beads was investigated in a batch system. Alginate beads were prepared from Na-alginate via cross-linking with divalent calcium ions according to the egg box model. The effect of several parameters such as pH, initial strontium concentration, contact time, dosage of alginate beads and temperature were investigated. In order to optimize the design of biosorption system for the removal of strontium, it is important to establish the most appropriate correlation for equilibrium curves. The experimental isotherm data were described by 6 different biosorption isotherm models, namely Langmuir, Freundlich, Dubinin-Radushkevich, Temkin, Flory-Huggins and Brunauer, Emmer and Teller, with constants obtained from linear and non-linear regression methods. The thermodynamic parameters (ΔHdeg, ΔSdeg and ΔGdeg) for strontium biosorption were also determined. The results indicate that these alginate beads have a good potential for the biosorption of strontium from solutions. (author)

  9. 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.

  10. Electro-Fenton decolourisation of dyes in an airlift continuous reactor using iron alginate beads.

    Science.gov (United States)

    Iglesias, O; Rosales, E; Pazos, M; Sanromán, M A

    2013-04-01

    In this study, electro-Fenton dye degradation was performed in an airlift continuous reactor configuration by harnessing the catalytic activity of Fe alginate gel beads. Electro-Fenton experiments were carried out in an airlift reactor with a working volume of 1.5 L, air flow of 1.5 L/min and 115 g of Fe alginate gel beads. An electric field was applied by two graphite bars connected to a direct current power supply with a constant potential drop. In this study, Lissamine Green B and Reactive Black 5 were selected as model dyes. Fe alginate gel beads can be used as an effective heterogeneous catalyst for the degradation of organic dyes in the electro-Fenton process, as they are more efficient than the conventional electrochemical techniques. At optimal working conditions (3 V and pH 2), the continuous process was performed. For both dyes, the degree of decolourisation increases when the residence time augments. Taking into account hydrodynamic and kinetic behaviour, a model to describe the reactor profile was obtained, and the standard deviation between experimental and theoretical data was lower than 6%. The results indicate the suitability of the electro-Fenton technique to oxidise polluted effluents in the presence of Fe alginate gel beads. Moreover, the operation is possible in a continuous airlift reactor, due to the entrapment of iron in the alginate matrix. PMID:22851224

  11. Bead-on-plate weldability of Al 5052 alloy using a disk laser

    Directory of Open Access Journals (Sweden)

    J.-K. Kim

    2008-06-01

    Full Text Available Purpose: The paper presents the effect of the laser welding parameters of the laser focal position and beam angle on the weldability of an Al 5052 thick plate using a 4kW disk laser.Design/methodology/approach: Bead-on-plate welding was conducted on a 10mm-thick Al 5052 plate. Aspects of the bead, including the bead surface and cross sections, were evaluated with various laser welding parameters. The porosity formation was also examined in an X-ray transmission tests.Findings: Although the penetration depth decreased as the focal point moves away from the surface, the appearance of the bead improved and the porosity decreased. The weldability according to the inclination angle of the laser beam was also investigated. It was found that a forward inclination of the laser beam (when the inclination angle is an acute angle could enhance the weldability compared with a backward inclination.Research limitations/implications: The results of the thick plate BOP welding experiments can be expanded to optimizing the Al alloy welding of thin sheets.Practical implications: It is applicable as a ground technique for the laser welding of aluminium alloy to increase the productivity and quality using the recently developed disk laser.Originality/value: The outcome of the research shows the influence of the welding parameters on weldability aspects in disk laser welding of an Al alloy.

  12. Tailored beads made of dissolved cellulose - Investigation of their drug release properties

    DEFF Research Database (Denmark)

    Yildir, Emrah; Kolakovic, Ruzica; Genina, Natalja;

    2013-01-01

    theophylline (Thp), riboflavin 5′-phosphate sodium (RSP) and lidocaine hydrochloride monohydrate (LiHCl) were used as model drug substances. The loading procedure was carried out by immersing swollen empty beads into the solutions of different concentrations of model drugs. The morphology of empty and loaded...

  13. Coupled acoustic-gravity field for dynamic evaluation of ion exchange with a single resin bead.

    Science.gov (United States)

    Kanazaki, Takahiro; Hirawa, Shungo; Harada, Makoto; Okada, Tetsuo

    2010-06-01

    A coupled acoustic-gravity field is efficient for entrapping a particle at the position determined by its acoustic properties rather than its size. This field has been applied to the dynamic observation of ion-exchange reactions occurring in a single resin bead. The replacement of counterions in an ion-exchange resin induces changes in its acoustic properties, such as density and compressibility. Therefore, we can visually trace the advancement of an ion-exchange reaction as a time change in the levitation position of a resin bead entrapped in the field. Cation-exchange reactions occurring in resin beads with diameters of 40-120 microm are typically completed within 100-200 s. Ion-exchange equilibrium or kinetics is often evaluated with off-line chemical analyses, which require a batch amount of ion exchangers. Measurements with a single resin particle allow us to evaluate ion-exchange dynamics and kinetics of ions including those that are difficult to measure by usual off-line analyses. The diffusion properties of ions in resins have been successfully evaluated from the time change in the levitation positions of resin beads. PMID:20462180

  14. Specificity and kinetics of norovirus binding to magnetic bead- conjugated histo-blood group antigens

    Science.gov (United States)

    Histo-blood group antigens (HBGA) have been identified as candidate receptors for human norovirus (NOR). Type A, type H1, and Lewis histo-blood group antigens (HBGAs) in humans have been identified as major targets for NOR binding. Pig HBGA-conjugated magnetic beads have been utilized as a means ...

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

    International Nuclear Information System (INIS)

    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

  16. Measurement of the diffusion coefficients of fluorescence beads and quantum dots by using fluorescence correlation spectroscopy

    International Nuclear Information System (INIS)

    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.

  17. 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.

  18. A flow cytometric assay technology based on quantum dots-encoded beads

    International Nuclear Information System (INIS)

    A flow cytometric detecting technology based on quantum dots (QDs)-encoded beads has been described. Using this technology, several QDs-encoded beads with different code were identified effectively, and the target molecule (DNA sequence) in solution was also detected accurately by coupling to its complementary sequence probed on QDs-encoded beads through DNA hybridization assay. The resolution of this technology for encoded beads is resulted from two longer wavelength fluorescence identification signals (yellow and red fluorescent signals of QDs), and the third shorter wavelength fluorescence signal (green reporting signal of fluorescein isothiocyanate (FITC)) for the determination of reaction between probe and target. In experiment, because of QDs' unique optical character, only one excitation light source was needed to excite the QDs and probe dye FITC synchronously comparing with other flow cytometric assay technology. The results show that this technology has present excellent repeatability and good accuracy. It will become a promising multiple assay platform in various application fields after further improvement

  19. Bacterial contamination of fabric and metal-bead identity card lanyards: a cross-sectional study.

    Science.gov (United States)

    Pepper, Thomas; Hicks, Georgina; Glass, Stephen; Philpott-Howard, John

    2014-01-01

    In healthcare, fabric or metal-bead lanyards are universally used for carrying identity cards. However there is little information on microbial contamination with potential pathogens that may readily re-contaminate disinfected hands. We examined 108 lanyards from hospital staff. Most grew skin flora but 7/108 (6%) had potentially pathogenic bacteria: four grew methicillin-susceptible Staphylococcus aureus, and four grew probable fecal flora: 3 Clostridium perfringens and 1 Clostridium bifermentans (one lanyard grew both S. aureus and C. bifermentans). Unused (control) lanyards had little or no such contamination. The median duration of lanyard wear was 12 months (interquartile range 3-36 months). 17/108 (16%) of the lanyards had reportedly undergone decontamination including wiping with alcohol, chlorhexidine or chlorine dioxide; and washing with soap and water or by washing machine. Metal-bead lanyards had significantly lower median bacterial counts than those from fabric lanyards (1 vs. 4 CFU/cm(2); Mann-Whitney U=300.5; P<0.001). 12/32 (38%) of the metal-bead lanyards grew no bacteria, compared with 2/76 (3%) of fabric lanyards. We recommend that an effective decontamination regimen be instituted by those who use fabric lanyards, or that fabric lanyards be discarded altogether in preference for metal-bead lanyards or clip-on identity cards. PMID:25151656

  20. Inflammatory response to therapeutic gold bead implantation in canine hip joint osteoarthritis.

    Science.gov (United States)

    Lie, K-I; Jæger, G; Nordstoga, K; Moe, L

    2011-11-01

    Inflammatory changes associated with periarticular pure gold bead implants were studied in dogs involved in a clinical trial investigating motor dysfunction and chronic pain owing to hip joint dysplasia and osteoarthritis. Gold beads were percutaneously implanted via a needle into different locations surrounding the greater trochanter of the femur. Nine dogs with implants were necropsied. In all examined animals, characteristic histologic lesions were observed in the tissue surrounding the gold implants--namely, a fibrous capsule composed of concentric fibroblasts intermixed with a variable number of inflammatory cells and a paucicellular innermost layer of collagen with a few fibrocyte-like cells in empty lacunae. Lymphocytes dominated the inflammatory infiltrate, with rarely observed macrophages present in close proximity to the implant site. No giant cells were observed. Immunohistochemistry showed mixed populations of lymphocytes, both CD3 positive (T cells) and CD79a positive (B cells), which in some cases formed lymphoid follicles. Diffuse inflammatory changes were present to a minor extent in the perimysium and surrounding fascia. The inflammation observed in dogs is similar to that observed with gold implants in humans. It is possible that the clinically beneficial effect of gold beads for chronic osteoarthritis depends on sustained localized inflammation with localized release of soluble mediators. The encapsulation of the implant by a paucicellular and poorly vascularized fibrous capsule may help prevent an exaggerated inflammatory reaction by sequestering the gold bead from the surrounding tissue. PMID:20861497

  1. 49 CFR 173.221 - Polymeric beads, expandable and Plastic molding compound.

    Science.gov (United States)

    2010-10-01

    ... Than Class 1 and Class 7 § 173.221 Polymeric beads, expandable and Plastic molding compound. (a) Non... molding compound in dough, sheet or extruded rope form, evolving flammable vapor must be packed in: wooden... flammable vapor or Plastic molding compounds in dough, sheet or extruded rope, evolving flammable vapor...

  2. 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; Folch-Puy, Emma; Foronjy, Robert; Jalili, Roxana; Jendresen, Christian Bille; Kimura, Masashi; Kraft, Edward; Lindemose, Søren; Lu, Jin; McLain, Teri; Nutt, Leta; Ramon-Garcia, Santiago; Smith, Joseph; Spivak, Aaron; Wang, Michael L; Zanic, Marija; Lin, Sue-Hwa

    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 membran...

  3. 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...

  4. Biodegradable IPN hydrogel beads of pectin and grafted alginate for controlled delivery of diclofenac sodium.

    Science.gov (United States)

    Giri, Tapan Kumar; Thakur, Deepa; Alexander, Amit; Ajazuddin; Badwaik, Hemant; Tripathy, Minaketan; Tripathi, Dulal Krishna

    2013-05-01

    A novel diclofenac sodium (DS) loaded interpenetrating polymer network (IPN) beads of pectin and hydrolyzed polyacrylamide-graft-sodium alginate (PAAm-g-SA) was developed through ionotropic gelation and covalent cross-linking. The graft copolymer was synthesized by free radical polymerization under the nitrogen atmosphere followed by alkaline hydrolysis. The grafting, alkaline hydrolysis, and characterization of beads were confirmed by Fourier transforms infrared spectroscopy. The crystalline structure of drug after encapsulation into IPN beads were evaluated by differential scanning colorimetry and X-ray diffraction analyses. DS encapsulation was up to 96.45 %. The effect of hydrolyzed graft copolymer/pectin ratios and glutaraldehyde concentration on drug release in acidic and phosphate buffer solutions were investigated. The release of drug was significantly increased with increase of pH. The release of drug depends on the extent of cross-linking. The results indicated that IPN beads of hydrolyzed PAAm-g-SA and pectin could be used for sustained release of DS. PMID:23423649

  5. 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. PMID:23259589

  6. Facile Fabrication of Polymerizable Ionic Liquid Based-Gel Beads via Thiol-ene Chemistry.

    Science.gov (United States)

    Taghavikish, Mona; Subianto, Surya; Dutta, Naba Kumar; Choudhury, Namita Roy

    2015-08-12

    Multipurpose gel beads prepared from natural or synthetic polymers have received significant attention in various applications such as drug delivery, coatings, and electrolytes because of their versatility and unique performance as micro- and nanocontainers.1 However, comparatively little work has been done on poly(ionic liquid)-based materials despite their unique ionic characteristics. Thus, in this contribution we report the facile preparation of polymerizable ionic liquid-based gel beads using thiol-ene click chemistry. This novel system incorporates pentaerythritol tetra (3-mercaptopropionate) (PETKMP) and 1,4-di(vinylimidazolium) butane bisbromide in a thiol-ene-based photopolymerization to fabricate the gel beads. Their chemical structure, thermal and mechanical properties have been investigated using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA). The gel beads possess low Tg and their ionic functionalities attribute self-healing properties and their ability to uptake small molecules or organic compounds offers their potential use as pH sensing material and macrocontainers. PMID:26171715

  7. Piroxicam loaded alginate beads obtained by prilling/microwave tandem technique: morphology and drug release.

    Science.gov (United States)

    Aquino, Rita P; Auriemma, Giulia; d'Amore, Matteo; D'Ursi, Anna Maria; Mencherini, Teresa; Del Gaudio, Pasquale

    2012-07-01

    This paper presents a tandem technique, based on the combination of prilling and microwave (MW) assisted treatments, to produce biodegradable alginate carriers of piroxicam with different drug controlled release behaviours. Results showed that alginate/piroxicam beads demonstrated high encapsulation efficiency and very narrow dimensional distribution. Beads dried by MW retained shape and size distribution of the hydrated particles while drying rate was strongly increased compared to convective drying processes. Moreover, different MW irradiation regimes promoted interactions between the drug and alginate matrix, affected drug polymorphism as well as inner and surface matrix structure leading to different piroxicam release profiles. High level MW irradiation led to beads with highly porous and swellable matrix able to release piroxicam in few minutes in the intestine while convective drying produced gastro-resistant beads that exhibit sustained piroxicam release (total release in 5.5h) in intestinal environment. On these results the tandem technique prilling/MW irradiation appears to be promising to obtain alginate carrier with tailored NSAIDs release depending on drug characteristics and MW irradiation. PMID:24750857

  8. 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. PMID:19589674

  9. A magnetic bead-based ligand binding assay to facilitate human kynurenine 3-monooxygenase drug discovery.

    Science.gov (United States)

    Wilson, Kris; Mole, Damian J; Homer, Natalie Z M; Iredale, John P; Auer, Manfred; Webster, Scott P

    2015-02-01

    Human kynurenine 3-monooxygenase (KMO) is emerging as an important drug target enzyme in a number of inflammatory and neurodegenerative disease states. Recombinant protein production of KMO, and therefore discovery of KMO ligands, is challenging due to a large membrane targeting domain at the C-terminus of the enzyme that causes stability, solubility, and purification difficulties. The purpose of our investigation was to develop a suitable screening method for targeting human KMO and other similarly challenging drug targets. Here, we report the development of a magnetic bead-based binding assay using mass spectrometry detection for human KMO protein. The assay incorporates isolation of FLAG-tagged KMO enzyme on protein A magnetic beads. The protein-bound beads are incubated with potential binding compounds before specific cleavage of the protein-compound complexes from the beads. Mass spectrometry analysis is used to identify the compounds that demonstrate specific binding affinity for the target protein. The technique was validated using known inhibitors of KMO. This assay is a robust alternative to traditional ligand-binding assays for challenging protein targets, and it overcomes specific difficulties associated with isolating human KMO. PMID:25296660

  10. 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.

  11. 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.

  12. Influence of polyethylene microplastic beads on the uptake and localization of silver in zebrafish (Danio rerio)

    DEFF Research Database (Denmark)

    Khan, Farhan R.; Syberg, Kristian; Shashoua, Yvonne; Bury, Nicolas R.

    2015-01-01

    This study aimed to determine whether the uptake and localization of Ag in zebrafish was affected by the presence of polyethylene microplastic beads (PE MPBs). Zebrafish were exposed to 1 μg Ag L−1 (radiolabelled with 110mAg) for 4 and 24 h in the presence or absence of PE MPBs (10, 100 or 1000...

  13. Ionotropically gelled novel hydrogel beads: Preparation, characterization and in vitro evaluation

    Directory of Open Access Journals (Sweden)

    J S Patil

    2011-01-01

    Full Text Available Prolonged release drug delivery system of stavudine was made by ionotropic gelation and polyelectrolyte complexation technique. Cross-linking reinforced chitosan-gellan complex beads were prepared by gelation of anionic gellan gum, the primary polymer, with oppositely charged counter ion to form beads which were further complexed with chitosan as a polyelectrolyte. The effect of this polymer on release profile of drug was studied. Beads without chitosan complexation were also made. The reaction of chitosan-gellan complex dominates the formation of skin layer on the surface of beads. Stavudine an antiretroviral drug was selected as novel drug for the experiment. The final formulations were subjected to in vitro evaluation and several characterization studies. Batches with gellan gum shows Higuchi model, while chitosan-gellan shows zero order release. All the batches with copolymer showed sustained the drug release more than 12 h, whereas with gellan gum alone showed up to 10 h. Batches with chitosan showed maximum drug encapsulation efficiency.

  14. EFFECT OF MIG WELDING INPUT PROCESS PARAMETERS ON WELD BEAD GEOMETRY ON HSLA STEEL

    OpenAIRE

    MOHD. SHOEB; Prof. Mohd. Parvez; Prof. Pratibha Kumari

    2013-01-01

    The various welding parameters such as welding speed, voltage and gas flow rate were varied on HSLA steel and the effects of these parameters on weld bead geometry such as penetration, width & height have been studied. Mathematical equations have been developed using factorial technique. And the result of various effects are shown in tables. (Numerical Values).

  15. EFFECT OF MIG WELDING INPUT PROCESS PARAMETERS ON WELD BEAD GEOMETRY ON HSLA STEEL

    Directory of Open Access Journals (Sweden)

    MOHD. SHOEB

    2013-01-01

    Full Text Available The various welding parameters such as welding speed, voltage and gas flow rate were varied on HSLA steel and the effects of these parameters on weld bead geometry such as penetration, width & height have been studied. Mathematical equations have been developed using factorial technique. And the result of various effects are shown in tables. (Numerical Values.

  16. 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 ena

  17. Chitosan hydrogel beads impregnated with hexadecylamine for improved reactive blue 4 adsorption.

    Science.gov (United States)

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

    2016-02-10

    Adsorption performance of chitosan (CS) hydrogel beads was investigated after impregnation of CS with hexadecylamine (HDA) as a cationic surfactant, for the elimination of reactive blue 4 (RB4) from wastewater. The CS/HDA beads formed with 3.8% HDA were the most effective adsorbent. The adsorption capacity was increased by 1.43 times from 317 mg/g (CS) to 454 mg/g (CS/HDA). The RB4 removal increased with decrease in the pH of dye solution from 4 to 9. The isotherm data obtained from RB4 adsorption on CS and CS/HDA are adequately described by Freundlich model (R(2)=0.946 and 0.934, χ(2)=22.414 and 64.761). The kinetic study revealed that the pseudo-second-order rate model (R(2)=0.996 and 0.997) was in better agreement with the experimental data. The negative values of ΔG° (-2.28 and -6.30 kJ/mol) and ΔH° (-172.18 and -101.62 kJ/mol) for CS beads and HDA modified CS beads, respectively; suggested a spontaneous and exothermic process for RB4 adsorption. PMID:26686114

  18. Multiscale study of nanoparticle-wall interactions in electroosmotic flow

    Science.gov (United States)

    Conlisk, A. T.; Zambrano, Harvey; Peng, Zhizi

    2011-11-01

    In electroosmotic transport (EOT), particle mobility results not only from the dragging exerted by the electrolyte, but also from the force exerted by the External Electric Field (EEF), and from the interactions with the walls and with the solvent. The objective of this work is to develop a unified theory of the motion of colloidal particles near walls and compare with the experiments of Kazoe and Yoda for EOT. In the present study a novel continuum approach is developed to study the particle interactions with polystyrene beads. Moreover, we conduct Non-equilibrium Molecular Dynamics Simulations (NEMDS) of a nanoparticle as it moves near a solid-liquid interface subjected to an EEF. We investigate the response of the particle to changes in the surface electrostatics and the electrolyte concentration. Therefore, we perform NEMDS of a silica particle immersed in an electrolyte. The electrolyte solution is mounted on a silica substrate and the particle is constrained to move parallel to the surface so that we can extract the forces acting between the particle and the wall. We vary the electrolyte concentration, the particle size and the surface electrostatics. Supported by the Army Research Office, the National Science Foundation NSEC Center for the Affordable Nanoengineering of Polymeric Biomedical Devices

  19. Comparison of clinical and MR imaging outcomes after uterine fibroid embolization with Bead Block and Embosphere

    International Nuclear Information System (INIS)

    Purpose: To compare clinical and imaging outcomes after uterine fibroid embolization (UFE) with Embosphere versus Bead Block microspheres. Materials and methods: Our institutional review board approved this HIPAA-compliant study. We conducted a retrospective review of all consecutive UFEs performed for symptomatic uterine fibroids at our academic institution from 2001 to 2008. UFE was performed using Embosphere (n = 70) or Bead Block (n = 55) microspheres. Patient symptoms and MR images were reviewed before and following UFE. The MR images were analyzed for changes in the size and contrast enhancement of the dominant fibroid and the uterus. Results: 125 patients underwent UFE. Pre-treatment characteristics (patient age, presenting symptoms, fibroid location, and volume of the largest fibroid) were similar across groups. Procedure endpoint (near-stasis, reached in 94% of cases), duration, and sedation medication doses were also similar. Clinical follow-up was available in 69 (55%) patients (mean duration: 13.6 months). Of these, 92% had clinical improvement of their main presenting symptom(s) and 3% developed early menopause. MRI follow-up was available in 105 (84%) patients (mean 7.8 months). Mean volume reduction of the largest fibroid was similar after Embosphere (48%) and Bead Block (53%, p = NS). Residual enhancement ≥5% in the dominant fibroid was similarly uncommon after Bead Block (19%) or Embosphere (16%, p = NS). Mean uterine volume reduction was similar across groups (38%); no myometrial infarction occurred. Conclusion: This retrospective study showed no superiority of Embosphere over Bead Block microspheres in terms of clinical and imaging outcomes after UFE.

  20. Immobilization and characterization of beta-galactosidase in thermally reversible hydrogel beads.

    Science.gov (United States)

    Park, T G; Hoffman, A S

    1990-01-01

    Beta-Galactosidase has been immobilized within thermally reversible hydrogel beads and has been studied in batch and packed bed reactor systems. The enzyme was entrapped in a copolymer hydrogel of N-isopropylacrylamide (NIPAAm) and acrylamide (AAm) as beads were formed in an inverse suspension polymerization. A reversible deswelling and reswelling of the hydrogel matrix was induced by first warming and then cooling through 37-40 degrees C, which is the lower critical solution temperature, LCST, of the backbone copolymer. The optimum temperature for maximum activity of the immobilized enzyme-gel bead system was found to be 30-35 degrees C in a batch mode and 40 degrees C in a packed bed reactor, which were both below the 50 degrees C optimum for the free enzyme. These differences are understandable, since the mass transfer rates of substrate and product within the pores of the gel matrix are controlled mainly by the temperature, so therefore it is the temperature which governs the overall activity of the immobilized enzyme system. It was also found that when the operational temperature in the packed bed reactor was cycled between temperatures below (35 degrees C) and above (45 degrees C) the copolymer gel LCST, the activity of the immobilized enzyme almost fully recovered after each cycle. In fact, the enzyme-gel system exhibited a complete "shut-off" in activity at 50 degrees C which was the temperature where the free enzyme showed its maximum activity. The thermal cycling operation of LCST enzyme-gel beads can be used to enhance overall activity and productivity of a packed bed reactor, when compared to isothermal operation of this reactor. This is due to the thermally induced "pumping" which enhances mass transfer rates of substrate in and product out of the gel beads. PMID:2105961

  1. 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

  2. Fly on the Wall

    Science.gov (United States)

    Berry, Dave; Korpan, Cynthia

    2009-01-01

    This paper describes the implementation of a peer observation program at the University of Victoria called the Lecture Club. The observers are not interactive during the class--they are the proverbial flies on the wall. The paper identifies the program as self-developmental, discussing the attributes of this learning-to-teach and peer-sharing…

  3. Endometriosis Abdominal wall

    International Nuclear Information System (INIS)

    Endometriosis of abdominal wall is a rare entity wi ch frequently appears after gynecological surgery. Case history includes three cases of parietal endometriosis wi ch were treated in Maciel Hospital of Montevideo. The report refers to etiological diagnostic aspects and highlights the importance of total resection in order to achieve definitive healing

  4. Anterior vaginal wall repair

    Science.gov (United States)

    ... symptoms will go away. This improvement will often last for years. Alternative Names A/P repair; Vaginal wall repair; Anterior and/ ... writing by ADAM Health Solutions. About MedlinePlus Site Map FAQs Contact ... Institutes of Health Page last updated: 23 August 2016

  5. The Invisible Wall.

    Science.gov (United States)

    Zenger, John H.

    1997-01-01

    The barrier to a company's performance may be a conflict of organizational values and culture with those of the training profession. Elements of this value system that create the invisible wall are egalitarianism, people focus, "guerilla" training tactics, and emphasis on human interaction. (JOW)

  6. 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

    2016-05-01

    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. PMID:27057765

  7. Moisture Research - Optimizing Wall Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Arena, Lois [Consortium for Advanced Residential Buildings (CARB), Norwalk, CT (United States); Mantha, Pallavi [Consortium for Advanced Residential Buildings (CARB), Norwalk, CT (United States)

    2013-05-01

    In this project, the Consortium for Advanced Residential Buildings (CARB) team evaluated several different configurations of wall assemblies to determine the accuracy of moisture modeling and make recommendations to ensure durable, efficient assemblies. WUFI and THERM were used to model the hygrothermal and heat transfer characteristics of these walls. Wall assemblies evaluated included code minimum walls using spray foam insulation and fiberglass batts, high R-value walls at least 12 in. thick (R-40 and R-60 assemblies), and brick walls with interior insulation.

  8. PC-88A - impregnated polymeric beads. Preparation, characterization and application for extraction of Pu(IV) from nitric acid medium

    International Nuclear Information System (INIS)

    The extractant-impregnated polymeric beads (EIPBs), containing polyethersulfone as base polymer and 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (PC-88A) as an extractant, were prepared by phase inversion method. These EIPBs were characterized by FTIR, TGA and SEM techniques. The beads were found to have excellent acid stability, since these did not exhibit any structural deformation or loss of the extractant into aqueous nitric acid solution (6 M), for a period of 15 d. The feasibility of Pu(IV) extraction, using these beads, from nitric acid solution was tested by batch equilibration method. Parametric dependence of Pu(IV) extraction on experimental variables, like strength of nitric acid, equilibration time, Pu(IV) concentration, etc., was investigated. The present study also addressed the important practical issues, like maximum loading capacity and the reusability of these beads. Under optimized conditions, equilibrium capacity and maximum loading capacity for Pu(IV) were found to be 2.03 and 7.50 mg per gram of the swollen beads, respectively. The reusability of the beads was also ascertained by repetitive extraction-stripping of Pu(IV) up to 7 cycles of operation, without significant change in their extraction performance. The extraction of Pu(IV) by the blank polymeric beads was observed to be almost negligible, under the similar experimental conditions. (orig.)

  9. Effect of methacrylic acid beads on the sonic hedgehog signaling pathway and macrophage polarization in a subcutaneous injection mouse model.

    Science.gov (United States)

    Lisovsky, Alexandra; Zhang, David K Y; Sefton, Michael V

    2016-08-01

    Poly(methacrylic acid-co-methyl methacrylate) (MAA) beads promote a vascular regenerative response when used in diabetic wound healing. Previous studies reported that MAA beads modulated the expression of sonic hedgehog (Shh) and inflammation related genes in diabetic wounds. The aim of this work was to follow up on these observations in a subcutaneous injection model to study the host response in the absence of the confounding factors of diabetic wound healing. In this model, MAA beads improved vascularization in healthy mice of both sexes compared to control poly(methyl methacrylate) (MM) beads, with a stronger effect seen in males than females. MAA-induced vessels were perfusable, as evidenced from the CLARITY-processed images. In Shh-Cre-eGFP/Ptch1-LacZ non-diabetic transgenic mice, the increased vessel formation was accompanied by a higher density of cells expressing GFP (Shh) and β-Gal (patched 1, Ptch1) suggesting MAA enhanced the activation of the Shh pathway. Ptch1 is the Shh receptor and a target of the pathway. MAA beads also modulated the inflammatory cell infiltrate in CD1 mice: more neutrophils and more macrophages were noted with MAA relative to MM beads at days 1 and 7, respectively. In addition, MAA beads biased macrophages towards a MHCII-CD206+ ("M2") polarization state. This study suggests that the Shh pathway and an altered inflammatory response are two elements of the complex mechanism whereby MAA-based biomaterials effect vascular regeneration. PMID:27264502

  10. Electrical and gas sensing properties of binder-free bead of SnO/sub 2/ powder

    International Nuclear Information System (INIS)

    An aqueous paste of commercial powder of SnO/sub 2/, containing no binding additives, was manually molded into a spherical bead of -3 mm diameter and was allowed to dry in air at the tips of two parallel copper wires, inserted there in the bead while in the wet state. The bead was positioned in a self-fabricated thermostatically controlled glass reactor and subjected to heat treatment in the thermal cycle, performed in the temperature range 150 -350 degree C in the ambient of nitrogen, static air, and dynamic air either clean or loaded with varying amounts of the automobile exhaust gases. It was noted that thermal cycle significantly affected the shape of the electrical resistance vs temperature trace of the bead, irrespective of the nature of the reactor ambient. The observed results were ascribed to the dependence of the bulk and surface properties of the bead material to the given treatment and ambient composition in a sensitive manner. Moreover, it was found that the presence of automobile exhaust gases caused a reduction in the resistance of the bead matelial at the given temperature. The latter facts were explained on the basis of the interaction of the reducing components of the automobile gases with the oxygen molecules, present on the surface of the bead in the adsorbed state. (author)

  11. X-ray fluorescent analysis on Indo-Pacific glass beads from Sungai Mas archaeological sites, Kedah, Malaysia

    International Nuclear Information System (INIS)

    Sungai Mas was an ancient port-kingdom located on West Coast of Peninsula Malaysia in a district of Kota Kuala Muda, Kedah, Malaysia. The port-kingdom evolved as an entrepot since fifth century AD and continuously visited by international trader from India, China, Middle East and Europe until eighteenth century AD. Sungai Mas was also one of the Indo-Pacific beads making centers in Southeast Asia since sixth to thirteenth century AD and also produced pottery and brick. X-ray fluorescent analysis (XRF) on Sungai Mas Indo-Pacific beads is carried out to determine whether the glass beads originated from Arikamedu, India or locally made by community in Sungai Mas. Totally, twenty-two samples of beads and beads materials assayed by XRF were chosen. Contents of nine major elements and nine trace elements, which might be present of flux, stabilizer, colorants or opacifier were examined. The elements Si, Na, K, Ca, Fe, Al, Ti, Mn, Mg, Cu, Pb, Zr, Sr, Ba, La, U, Ni and Cr were detectable in all samples. The concentration of elements found are discussed in terms of flux, silica or lead base glass, color and/or opacity of the glass beads and glass samples. The result showed that Sungai Mas produced their own Indo-Pacific beads from sixth to thirteenth century AD. (author)

  12. Post-crosslinking towards stimuli-responsive sodium alginate beads for the removal of dye and heavy metals.

    Science.gov (United States)

    Lu, Ting; Xiang, Tao; Huang, Xue-Lian; Li, Cheng; Zhao, Wei-Feng; Zhang, Qian; Zhao, Chang-Sheng

    2015-11-20

    Post-crosslinking as a new strategy to prepare sodium alginate (SA) beads with controllable swelling behavior, pH sensitivity and adsorption capacity was developed by using the solution of glutaraldehyde (GA), acetic acid and hydrochloric acid as the coagulating agent, for which could be used to fabricate polysaccharide beads in a large scale. Fourier transform infrared spectroscopy and thermogravimetric analysis convinced the successful cross-linking of SA by GA. The macro-porous structures of the beads were observed by scanning electron microscopy. Both acetic acid and hydrochloric acid had great effects on the swelling behavior and pH sensitivity of the SA beads. The SA beads could adsorb cationic dye (methylene blue) as high as 572mg/g and other metal ions (Cu(2+), Ag(+) and Fe(3+)). The adsorption processes fitted well with the pseudo-second-order kinetic model and the Freundlich isotherm. The large-scale production of SA beads with tunable properties opens a new route to industrially utilize polysaccharide beads in wastewater treatments, intelligent separation and so on. PMID:26344317

  13. Rising damp in building walls: the wall base ventilation system

    Science.gov (United States)

    Guimarães, A. S.; Delgado, J. M. P. Q.; de Freitas, V. P.

    2012-12-01

    This work intends to validate a new system for treating rising damp in historic buildings walls. The results of laboratory experiments show that an efficient way of treating rising damp is by ventilating the wall base, using the HUMIVENT technique. The analytical model presented describes very well the observed features of rising damp in walls, verified by laboratory tests, who contributed for a simple sizing of the wall base ventilation system that will be implemented in historic buildings.

  14. Colonic drug delivery: influence of cross-linking agent on pectin beads properties and role of the shell capsule type.

    Science.gov (United States)

    Dupuis, G; Chambin, O; Génelot, C; Champion, D; Pourcelot, Y

    2006-08-01

    For colonic delivery, pectin beads obtained by ionotropic gelation method have been already reported as an interesting approach. This study investigated the influence of the cross-linking agent (calcium or zinc) and the type of shell capsule used (classical or enteric capsules) on pectin beads properties and on their performance to target the colon (in vitro dissolution studies with subsequent pH change to mimic overall gastro-intestinal tract). Zinc pectinate beads seemed to be relatively similar to calcium's ones in morphological point, except on the surface aspect. When beads were introduced in classical hard capsules, ketoprofen release was not significantly different between CPG and ZPG beads, and it was too premature and too quick due to a chemical erosion of the pectinate matrix (acid + basic attacks). However, zinc pectinate beads showed slower ketoprofen release compared with calcium pectinate beads when enteric hard capsules were used. This interesting finding could be due to the strength of the network formed during the process between the zinc cations and the LM-pectin following the "egg-box" model. This network was stronger and induced a reduction of swelling and hydration when contact with dissolution medium, then subsequently a decrease of drug release. Thus, the zinc pectinate beads could protect sufficiently drug entrapped from the upper gastro-intestinal conditions and drug release will be controlled by pectin degradation with colonic microflora. Finally, these zinc pectinate beads in enteric hard capsules are promising as a carrier for specific colonic delivery of drugs after oral administration. PMID:16908422

  15. High-R Walls for Remodeling: Wall Cavity Moisture Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Wiehagen, J.; Kochkin, V.

    2012-12-01

    The focus of the study is on the performance of wall systems, and in particular, the moisture characteristics inside the wall cavity and in the wood sheathing. Furthermore, while this research will initially address new home construction, the goal is to address potential moisture issues in wall cavities of existing homes when insulation and air sealing improvements are made.

  16. High-R Walls for Remodeling. Wall Cavity Moisture Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Wiehagen, J. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States); Kochkin, V. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States)

    2012-12-01

    The focus of the study is on the performance of wall systems, and in particular, the moisture characteristics inside the wall cavity and in the wood sheathing. Furthermore, while this research will initially address new home construction, the goal is to address potential moisture issues in wall cavities of existing homes when insulation and air sealing improvements are made.

  17. Automatic Wall Painting Robot

    Directory of Open Access Journals (Sweden)

    P.KEERTHANAA, K.JEEVITHA, V.NAVINA, G.INDIRA, S.JAYAMANI

    2013-07-01

    Full Text Available The Primary Aim Of The Project Is To Design, Develop And Implement Automatic Wall Painting Robot Which Helps To Achieve Low Cost Painting Equipment. Despite The Advances In Robotics And Its Wide Spreading Applications, Interior Wall Painting Has Shared Little In Research Activities. The Painting Chemicals Can Cause Hazards To The Human Painters Such As Eye And Respiratory System Problems. Also The Nature Of Painting Procedure That Requires Repeated Work And Hand Rising Makes It Boring, Time And Effort Consuming. When Construction Workers And Robots Are Properly Integrated In Building Tasks, The Whole Construction Process Can Be Better Managed And Savings In Human Labour And Timing Are Obtained As A Consequence. In Addition, It Would Offer The Opportunity To Reduce Or Eliminate Human Exposure To Difficult And Hazardous Environments, Which Would Solve Most Of The Problems Connected With Safety When Many Activities Occur At The Same Time. These Factors Motivate The Development Of An Automated Robotic Painting System.

  18. Scalable Resolution Display Walls

    KAUST Repository

    Leigh, Jason

    2013-01-01

    This article will describe the progress since 2000 on research and development in 2-D and 3-D scalable resolution display walls that are built from tiling individual lower resolution flat panel displays. The article will describe approaches and trends in display hardware construction, middleware architecture, and user-interaction design. The article will also highlight examples of use cases and the benefits the technology has brought to their respective disciplines. © 1963-2012 IEEE.

  19. In a walled garden

    OpenAIRE

    Mullaniff, Kathleen

    2009-01-01

    Mullaniff exhibited one painting from the series, ‘in a walled garden’. These works are based on a Victorian garden at St Leonards on Sea. An investigation into the history of the house and garden built 1860. This research endeavors to explore the progression of restoring the original Victorian garden, as recorded through the painting and drawing process This involves forming links between the past domestic histories and the current site. The research is based on the botanical paintings of Ma...

  20. Light shining through walls

    Energy Technology Data Exchange (ETDEWEB)

    Redondo, Javier [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Max-Planck-Institut fuer Physik, Muenchen (Germany); Ringwald, Andreas [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2010-11-15

    Shining light through walls? At first glance this sounds crazy. However, very feeble gravitational and electroweak effects allow for this exotic possibility. Unfortunately, with present and near future technologies the opportunity to observe light shining through walls via these effects is completely out of question. Nevertheless there are quite a number of experimental collaborations around the globe involved in this quest. Why are they doing it? Are there additional ways of sending photons through opaque matter? Indeed, various extensions of the standard model of particle physics predict the existence of new particles called WISPs - extremely weakly interacting slim particles. Photons can convert into these hypothetical particles, which have no problems to penetrate very dense materials, and these can reconvert into photons after their passage - as if light was effectively traversing walls. We review this exciting field of research, describing the most important WISPs, the present and future experiments, the indirect hints from astrophysics and cosmology pointing to the existence of WISPs, and finally outlining the consequences that the discovery of WISPs would have. (orig.)

  1. Light shining through walls

    International Nuclear Information System (INIS)

    Shining light through walls? At first glance this sounds crazy. However, very feeble gravitational and electroweak effects allow for this exotic possibility. Unfortunately, with present and near future technologies the opportunity to observe light shining through walls via these effects is completely out of question. Nevertheless there are quite a number of experimental collaborations around the globe involved in this quest. Why are they doing it? Are there additional ways of sending photons through opaque matter? Indeed, various extensions of the standard model of particle physics predict the existence of new particles called WISPs - extremely weakly interacting slim particles. Photons can convert into these hypothetical particles, which have no problems to penetrate very dense materials, and these can reconvert into photons after their passage - as if light was effectively traversing walls. We review this exciting field of research, describing the most important WISPs, the present and future experiments, the indirect hints from astrophysics and cosmology pointing to the existence of WISPs, and finally outlining the consequences that the discovery of WISPs would have. (orig.)

  2. A study of glass beads from Phum Snay Iron Age archaeological site and settlement, Cambodia Data from excavation in 2001 and 2003

    OpenAIRE

    Sophy SONG

    2010-01-01

    The study of beads in Phum Snay Iron Age Site and Settlement which is in danger since 2000 because it was looted the site and sold out its artifacts. There are 349 beads were analysis received from the archaeological data in both years excavation in 2001 and 2003. All of beads were analyzed macroscopic but only 100 beads were brought from Cambodia to Paris for the chemical analysis.Among them 75 glass beads were done with the compositional analysis by Laser Ablation Inductively Coupled Plasma...

  3. Canal Wall Reconstruction Mastoidectomy

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objective To investigate the advantages of canal wall reconstruction (CWR) mastoidectomy, a single-stage technique for cholesteatoma removal and posterior external canal wall reconstruction, over the open and closed procedures in terms of cholesteatoma recurrence. Methods: Between June 2002 and December 2005, 38 patients (40 ears) with cholesteatoma were admited to Sun Yat-Sen Memorial Hospital and received surgical treatments. Of these patients, 25 were male with ages ranging between 11 and 60 years (mean = 31.6 years) and 13 were female with ages ranging between 20 and 65 years (mean = 38.8 years). Canal wall reconstruction (CWR)mastoidectomy was performed in 31 ears and canal wall down (CWD) mastoidectomy in 9 ears. Concha cartilage was used for ear canal wall reconstruction in 22 of the 31 CWR procedures and cortical mastoid bone was used in the remaining 9 cases. Results At 0.5 to 4 years follow up, all but one patients remained free of signs of cholesteatoma recurrence, i.e., no retraction pocket or cholesteatoma matrix. One patient, a smoker, needed revision surgery due to cholesteatoma recurrence 1.5 year after the initial operation. The recurrence rate was therefore 3.2% (1/31). Cholesteatoma recurrence was monitored using postoperative CT scans whenever possible. In the case that needed a revision procedure, a retraction pocket was identified by otoendoscopy in the pars flacida area that eventually evolved into a cholesteatoma. A pocket extending to the epitympanum filled with cholesteatoma matrix was confirmed during the revision operation, A decision to perform a modified mastoidectomy was made as the patient refused to quit smoking. The mean air-bone gap in pure tone threshold was 45 dB before surgery and 25 dB after (p < 0.05). There was no difference between using concha cartilage and cortical mastoid bone for the reconstruction regarding air-bone gap improvement, CT findings and otoendoscopic results. Conclusion CWR mastoidectomy can be used for

  4. Cell Wall Biology: Perspectives from Cell Wall Imaging

    Institute of Scientific and Technical Information of China (English)

    Kieran J.D.Lee; Susan E.Marcus; J.Paul Knox

    2011-01-01

    Polysaccharide-rich plant cell walls are important biomaterials that underpin plant growth,are major repositories for photosynthetically accumulated carbon,and,in addition,impact greatly on the human use of plants. Land plant cell walls contain in the region of a dozen major polysaccharide structures that are mostly encompassed by cellulose,hemicelluloses,and pectic polysaccharides. During the evolution of land plants,polysaccharide diversification appears to have largely involved structural elaboration and diversification within these polysaccharide groups. Cell wall chemistry is well advanced and a current phase of cell wall science is aimed at placing the complex polysaccharide chemistry in cellular contexts and developing a detailed understanding of cell wall biology. Imaging cell wall glycomes is a challenging area but recent developments in the establishment of cell wall molecular probe panels and their use in high throughput procedures are leading to rapid advances in the molecular understanding of the spatial heterogeneity of individual cell walls and also cell wall differences at taxonomic levels. The challenge now is to integrate this knowledge of cell wall heterogeneity with an understanding of the molecular and physiological mechanisms that underpin cell wall properties and functions.

  5. On-bead chemical synthesis and display of phosphopeptides for affinity pull-down proteomics

    DEFF Research Database (Denmark)

    Malene, Brandt; Madsen, Jens C.; Bunkenborg, Jakob; Jensen, Ole N.; Gammeltoft, Steen; Jensen, Knud J.

    2006-01-01

    We describe a new method for phosphopeptide proteomics based on the solid-phase synthesis of phosphopeptides on beads suitable for affinity pull-down experiments. Peptide sequences containing the Bad Ser112 and Ser136 phosphorylation motifs were used as bait in affinity pull-down experiments to...... (aldehyde) at the C terminus for potential activity-based proteomics. The synthetic support-bound Bad phosphopeptides were able to pull down 14-3-3zeta. Furthermore, Bad phosphopeptides bound endogenous 14-3-3 proteins, and all seven members of the 14-3-3 family were identified by mass spectrometry. In...... control experiments, none of the unphosphorylated Bad peptides bound transfected 14-3-3zeta or endogenous 14-3-3. We conclude that the combined synthesis and display of phosphopeptides on-bead is a fast and efficient method for affinity pull-down proteomics....

  6. Double Emulsion Droplets as Microreactors for Synthesis of Magnetic Macroporous Polymer Beads

    Institute of Scientific and Technical Information of China (English)

    Wei-cai Wang; Chao Peng; Kai Shi; Yan-xiong Pan; Hai-shan Zhang; Xiang-ling Ji

    2014-01-01

    An easy method is presented to fabricate monodisperse magnetic macroporous polymer beads (MMPBs).Waterin-oil high intemal phase emulsion (HIPE) is prepared by emulsifying aqueous iron ions solution in an oil phase containing monomers.The HIPE is introduced into a simple microfluidic device to fabricate monodisperse (water-in-oil)-in-water double emulsion droplets.The droplets serve as microreactors to synthesize Fe3O4 nanoparticles and are on-line polymerized to form MMPBs.The prepared MMPBs display uniform size,interconnected porous structure,superparamagnetic behavior and uniform distribution of Fe3O4 in polymer matrix.The MMPBs are characterized by scanning electron microscopy (SEM),Fourier transform infrared spectroscopy (FTIR),X-ray diffraction (XRD),transmission electron microscopy (TEM),vibrating sample magnetometry (VSM).We believe that this method is a universal technique in preparing macroporous nanocomposite beads.

  7. Relation between electron beam welding parameters and appearances of weld beads on Nb plates

    International Nuclear Information System (INIS)

    We studied relations between electron beam welding parameters and appearances of weld beads. Allowed parameter regions to obtain a full penetration weld without hole or spattering, a relation between underbead width and EBW parameters, and a relation among a peak height, valley depth and underbead width were also examined. We found that a beam generator direction and beam sweep direction affect a geometry of weld bead dramatically, a focused beam cause a wide underbead, a peak height is proportional to underbead width for the vertical generator position, and neither a peak height nor valley depth shows a simple linearity as a function of underbead width for the horizontal generator position with horizontal beam sweep. (author)

  8. A fluorescent sandwich assay for thrombin using aptamer modified magnetic beads and quantum dots

    International Nuclear Information System (INIS)

    We describe an aptamer-based sandwich assay for thrombin by using a pair of thrombin-binding aptamers, namely one 15-mer aptamer (denoted as Apt15) and one 29-mer aptamer (denoted as Apt29). Either Apt29 or Apt15 can be used as capture aptamers on magnetic beads or reporter aptamers on the quantum dots to form the sandwich complex. Detection of thrombin is achieved by the fluorescent measurement of quantum dots in the sandwich complex. The choice of capture aptamers and reporter aptamers, and the effect of the addition order of the aptamers modified magnetic beads and the aptamers modified quantum dots were investigated. Detection of 0.05 nM thrombin was accomplished. The proteins hemoglobin, lysozyme, and transferrin did not interfere in this assay. (author)

  9. Development of a new antibacterial biomaterial by tetracycline immobilization on calcium-alginate beads.

    Science.gov (United States)

    Ozseker, Emine Erdogan; Akkaya, Alper

    2016-10-20

    In recent years, increasing risk of infection, caused by resistant microorganism to antibiotics, has become the limelight discovery of new and natural antibacterial materials. Heavy metals, such as silver, copper, mercury and titanium, have antibacterial activity. Products, which improved these metals, do not have stable antibacterial property. Therefore, use of these products is restricted. The aim of this study was to immobilize tetracycline to alginate and improve an antibacterial biomaterial. For this purpose, calcium-alginate beads were formed by dropping to calcium-chloride solution and tetracycline was immobilized to beads using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide at optimum conditions. After immobilization, actualization of immobilization was investigated by analyzing ATR-FTIR spectrum and SEM images. Also, antibacterial property of obtained product was tested. Improved product demonstrated antibacterial property. It has potential for open wound, surgical drapes, bed and pillow sheath in hospitals and it may also be used for increasing human comfort in daily life. PMID:27474587

  10. Improving the Stability of Astaxanthin by Microencapsulation in Calcium Alginate Beads.

    Science.gov (United States)

    Lin, Shen-Fu; Chen, Ying-Chen; Chen, Ray-Neng; Chen, Ling-Chun; Ho, Hsiu-O; Tsung, Yu-Han; Sheu, Ming-Thau; Liu, Der-Zen

    2016-01-01

    There has been considerable interest in the biological functions of astaxanthin and its potential applications in the nutraceutical, cosmetics, food, and feed industries in recent years. However, the unstable structure of astaxanthin considerably limits its application. Therefore, this study reports the encapsulation of astaxanthin in calcium alginate beads using the extrusion method to improve its stability. This study also evaluates the stability of the encapsulated astaxanthin under different storage conditions. The evaluation of astaxanthin stability under various environmental factors reveals that temperature is the most influential environmental factor in astaxanthin degradation. Stability analysis shows that, regardless of the formulation used, the content of astaxanthin encapsulated in alginate beads remains above 90% of the original amount after 21 days of storage at 25°C. These results suggest that the proposed technique is a promising way to enhance the stability of other sensitive compounds. PMID:27093175

  11. Fermentation and microencapsulation of the nematophagous fungus Hirsutella rhossiliensis in a novel type of hollow beads.

    Science.gov (United States)

    Patel, Anant V; Jakobs-Schönwandt, Desiree; Rose, Thomas; Vorlop, Klaus-Dieter

    2011-03-01

    In this work, fermentation and formulation aspects of the nematophagous fungus Hirsutella rhossiliensis BBA were investigated. When incubated in 2% (w/w) glucose and 0.5% (w/w) yeast extract medium in a 1-L Erlenmeyer flask without baffles, heavy pellet formation was observed. Only 40% of the mycelium had a size less than 500 μm. When a flask with three baffles was used, the portion of mycelium fermentation results were obtained at 0.4 vvm and 400 rpm stirrer speed with 90% mycelium gluten and 0.5% (w/w) yeast extract could be replaced with 3% (w/w) autoclaved baker's yeast which was never used as capsule additive before. Radial growth of mycelium out of dried hollow beads containing 1% (w/w) biomass and 3% (w/w) baker's yeast was faster than for alginate beads containing equivalent amounts of biomass and yeast indicating a higher bio-control potential. PMID:21181150

  12. A study on the prediction of bead geometry in the robotic welding system

    International Nuclear Information System (INIS)

    The gas metal are (GMA) welding is one of the most widely-used processes in metal joining process that involves the melting and solidification of the joined materials. To solve this problem, we have carried out the sequential experiment based on a Taguchi method and identified the various problems that result from the robotic GMA welding process to characterize the GMA welding process and establish guidelines for the most effective joint design. Also using multiple regression analysis with the help of a standard statistical package program, SPSS, on an IBM-compatible PC, three empirical models (linear, interaction, quadratic model) have been developed for off-line control which studies the influence of welding parameters on bead width and compares their influences on the bead width to check which process parameter is most affecting. These models developed have been employed for the prediction of optimal welding parameters and assisted in the generation of process control algorithms

  13. A micro-pillar array to trap magnetic beads in microfluidic systems

    KAUST Repository

    Gooneratne, Chinthaka Pasan

    2012-12-01

    A micro-pillar array (MPA) is proposed in this paper to trap and separate magnetic beads (MBs) in microfluidic systems. MBs are used in many biomedical applications due to being compatible in dimension to biomolecules, the large surface area available to attach biomolecules, and the fact that they can be controlled by a magnetic field. Trapping and separating these labeled biomolecules is an important step toward achieving reliable and accurate quantification for disease diagnostics. Nickel Iron (Ni50Fe 50) micro-pillars were fabricated on a Silicon (Si) substrate by standard microfabrication techniques. Experimental results showed that MBs could be trapped on the MPA at the single bead level and separated from other non-target particles. This principle can easily be extended to trap and separate target biomolecules in heterogeneous biological samples. © 2012 IEEE.

  14. Plant Roots Increase Bacterivorous Nematode Dispersion through Nonuniform Glass-bead Media.

    Science.gov (United States)

    Trap, Jean; Bernard, Laetitia; Brauman, Alain; Pablo, Anne-Laure; Plassard, Claude; Ranoarisoa, Mahafaka Patricia; Blanchart, Eric

    2015-12-01

    Dispersion of bacterivorous nematodes in soil is a crucial ecological process that permits settlement and exploitation of new bacterial-rich patches. Although plant roots, by modifying soil structure, are likely to influence this process, they have so far been neglected. In this study, using an original three-compartment microcosm experimental design and polyvinyl chloride (PVC) bars to mimic plant roots, we tested the ability of roots to improve the dispersion of bacterivorous nematode populations through two wet, nonuniform granular (glass bead) media imitating contrasting soil textures. We showed that artificial roots increased migration time of bacterivorous nematode populations in the small-bead medium, suggesting that plant roots may play an important role in nematode dispersion in fine-textured soils or when soil compaction is high. PMID:26941457

  15. A study on the prediction of bead geometry in the robotic welding system

    Energy Technology Data Exchange (ETDEWEB)

    Son, J. S. [MECS Co. Ltd., Pohang (Korea, Republic of); Kim, I. S.; Kim, H. H. [Mokpo National University, Mokpo (Korea, Republic of); Kim, I. J. [KlTECH, .......(Korea, Republic of); Kang, B. Y. [KlTECH, Incheon (Korea, Republic of); Kim, H. J. [KlTECH, Cheonan (Korea, Republic of)

    2007-10-15

    The gas metal are (GMA) welding is one of the most widely-used processes in metal joining process that involves the melting and solidification of the joined materials. To solve this problem, we have carried out the sequential experiment based on a Taguchi method and identified the various problems that result from the robotic GMA welding process to characterize the GMA welding process and establish guidelines for the most effective joint design. Also using multiple regression analysis with the help of a standard statistical package program, SPSS, on an IBM-compatible PC, three empirical models (linear, interaction, quadratic model) have been developed for off-line control which studies the influence of welding parameters on bead width and compares their influences on the bead width to check which process parameter is most affecting. These models developed have been employed for the prediction of optimal welding parameters and assisted in the generation of process control algorithms.

  16. Use of magnetic beads for tissue DNA extraction and IS6110 Mycobacterium tuberculosis PCR.

    OpenAIRE

    R. Caldarelli-Stefano; Vago, L.; Bonetto, S; Nebuloni, M; Costanzi, G.

    1999-01-01

    Polymerase chain reaction (PCR) techniques are used increasingly for the diagnosis of Mycobacterium tuberculosis infection and can be used on the DNA obtained from both frozen and formalin fixed, paraffin wax embedded tissues. However, the extraction of DNA by means of the conventional phenol/chloroform method is time consuming and requires the use of potentially dangerous chemical reagents. This paper describes a method based upon the use of magnetic beads for the extraction of M tuberculosi...

  17. Characteristics of CO2 Hydrate Formation and Dissociation in Glass Beads and Silica Gel

    OpenAIRE

    Qingping Li; Jiafei Zhao; Yu Liu; Xuke Ruan; Yongchen Song; Mingjun Yang

    2012-01-01

    CO 2 hydrate formation and dissociation is crucial for hydrate-based CO 2 capture and storage. Experimental and calculated phase equilibrium conditions of carbon dioxide (CO 2 ) hydrate in porous medium were investigated in this study. Glass beads were used to form the porous medium. The experimental data were generated using a graphical method. The results indicated the decrease of pore size resulted in the increase of the equilibrium pressure of CO 2 hydrate. Magnetic resonance imaging (MRI...

  18. Formulasi dan Evaluasi Secara In Vitro Floating Mucoadhesive Beads Dari Metronidazol Dengan Basis Alginat-Kitosan

    OpenAIRE

    Sitepu, Ali Wardana

    2015-01-01

    Salah satu kendala utama pada pengobatan ulkus yang disebabkan oleh H. pylori dengan sediaan konvensional adalah waktu tinggal obat yang singkat didalam lambung. Adapun beberapa sistem penghantaran obat ke lambung adalah floating dan mucoadhesive. Adapun tujuan dari penelitian ini adalah untuk membuat sediaan yang dapat bertahan lebih lama dalam lambung yang memiliki sifat floating dan mucoadhesive. Floating mucoadhesive beads dibuat dengan menggunakan basis alginat kitosan dan dibuat dala...

  19. Magnetic bead purification of labeled DNA fragments for high-throughput capillary electrophoresis sequencing

    OpenAIRE

    Elkin, Christopher; Kapur, Hitesh; Smith, Troy; Humphries, David; Pollard, Martin; Hammon, Nancy; Hawkins, Trevor

    2001-01-01

    We have developed an automated purification method for terminator sequencing products based on a magnetic bead technology. This 384-well protocol generates labeled DNA fragments that are essentially free of contaminates for less than $0.005 per reaction. In comparison to laborious ethanol precipitation protocols, this method increases the phred20 read length by forty bases with various DNA templates such as PCR fragments, Plasmids, Cosmids and RCA products. Our method eliminates centrifu...

  20. Influencing Factors on the Interface Microhardness of Lightweight Aggregate Concrete Consisting of Glazed Hollow Bead

    OpenAIRE

    Gang Ma; Yu Zhang; Zhu Li

    2015-01-01

    Lightweight aggregate concrete consisting of glazed hollow bead (GHB) as lightweight aggregate is studied for the influence of nanosilica (NS) content, prewetting time for GHB, water-cement ratio, and curing humidity, on the interface structure between GHB and cement paste. This research analyzed the influences of various factors on the interface zone structure by measuring microhardness (HV) and hydration degree of cement paste (HD) nearby the interface zone (1 mm) between GHB and cement pas...

  1. Some studies on weld bead geometries for laser spot welding process using finite element analysis

    International Nuclear Information System (INIS)

    Highlights: → In this study, a 2 kW Nd:YAG laser welding system is used to conduct laser spot welding trials. → The size and shape of the laser spot weld is predicted using finite element simulation. → The heat input is assumed to be a three-dimensional conical Gaussian heat source. → The result highlights the effect of beam incident angle on laser spot welds. → The achieved results of numerical simulation are almost identical with a real weldment. -- Abstract: Nd:YAG laser beam welding is a high power density welding process which has the capability to focus the beam to a very small spot diameter of about 0.4 mm. It has favorable characteristics namely, low heat input, narrow heat affected zone and lower distortions, as compared to conventional welding processes. In this study, finite element method (FEM) is applied for predicting the weld bead geometry i.e. bead length (BL), bead width (BW) and depth of penetration (DP) in laser spot welding of AISI 304 stainless steel sheet of thickness 2.5 mm. The input parameters of laser spot welding such as beam power, incident angle of the beam and beam exposure time are varied for conducting experimental trials and numerical simulations. Temperature-dependent thermal properties of AISI 304 stainless steel, the effect of latent heat of fusion, and the convective and radiative aspects of boundary conditions are considered while developing the finite element model. The heat input to the developed model is assumed to be a three-dimensional conical Gaussian heat source. Finite-element simulations of laser spot welding were carried out by using Ansys Parametric Design Language (APDL) available in finite-element code, ANSYS. The results of the numerical analysis provide the shape of the weld beads for different ranges of laser input parameters that are subsequently compared with the results obtained through experimentation and it is found that they are in good agreement.

  2. Bioleaching of Primary Nickel Ore Using Acidithiobacillus ferrooxidans LR Cells Immobilized in Glass Beads

    OpenAIRE

    Ellen Cristine Giese; Patrícia Morgado Vaz

    2015-01-01

    Sulphide minerals are one of the most important sources of value metals. For several years, a large number of hydrometallurgical and biotechnological processes have been developed to leach low-grade sulphide ores and the conditions are well established. However, the management of microorganisms in the bioleaching process is not easy to handle. In this paper, the use of immobilized cells of Acidithiobacillus ferrooxidans LR in glass beads in bioleaching of primary nickel ore was evaluated. The...

  3. Sprayable Aerogel Bead Compositions With High Shear Flow Resistance and High Thermal Insulation Value

    Science.gov (United States)

    Ou, Danny; Trifu, Roxana; Caggiano, Gregory

    2013-01-01

    A sprayable aerogel insulation has been developed that has good mechanical integrity and lower thermal conductivity than incumbent polyurethane spray-on foam insulation, at similar or lower areal densities, to prevent insulation cracking and debonding in an effort to eliminate the generation of inflight debris. This new, lightweight aerogel under bead form can be used as insulation in various thermal management systems that require low mass and volume, such as cryogenic storage tanks, pipelines, space platforms, and launch vehicles.

  4. Compressive and Fracture Properties of Syntactic Foam Filled with Hollow Plastic Bead(HPC)

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The compressive mechanical properties of syntactic foams reinforced by hollow plastic beads were studied by the quasi-static compression test. The failure mechanism of syntactic foams was also investigated by macroscopic and microscopic observation on the fractured specimens. The experimental results show that the density of syntactic foams is still the key factor affecting their mechanical properties. The macroscopic and microscopic observation on the fractured specimens indicates that the main failure mode is the elastic-plastic collapse caused by shear.

  5. On crack propagation in the welded polyolefin pipes with and without the presence of weld beads

    Czech Academy of Sciences Publication Activity Database

    Mikula, Jakub; Hutař, Pavel; Nezbedová, E.; Lach, R.; Arbeiter, F.; Ševčík, Martin; Pinter, G.; Grellmann, W.; Náhlík, Luboš

    2015-01-01

    Roč. 87, DEC (2015), s. 95-104. ISSN 0264-1275 R&D Projects: GA ČR(CZ) GAP108/12/1560; GA MŠk(CZ) EE2.3.30.0063; GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:68081723 Keywords : Slow crack growth * Butt weld * Lifetime estimation * Polyolefin pipes * Weld bead Subject RIV: JL - Materials Fatigue, Friction Mechanics

  6. Single Bead Affinity Detection (SINBAD) for the Analysis of Protein-Protein Interactions

    OpenAIRE

    Schulte, Roberta; Talamas, Jessica; Doucet, Christine; Hetzer, Martin W.

    2008-01-01

    We present a miniaturized pull-down method for the detection of protein-protein interactions using standard affinity chromatography reagents. Binding events between different proteins, which are color-coded with quantum dots (QDs), are visualized on single affinity chromatography beads by fluorescence microscopy. The use of QDs for single molecule detection allows the simultaneous analysis of multiple protein-protein binding events and reduces the amount of time and material needed to perform...

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

    Czech Academy of Sciences Publication Activity Database

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

    2014-01-01

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

  8. Hepatic Arterial Chemoembolization Using Drug-Eluting Beads in Gastrointestinal Neuroendocrine Tumor Metastatic to the Liver

    International Nuclear Information System (INIS)

    Purpose: This study was designed to evaluate short (3 months) follow-up in patients with metastatic neuroendocrine tumor to the liver who underwent hepatic arterial chemoembolization with drug-eluting beads at a single institution. Methods: Institutional review board approval was obtained for this retrospective review. All patients who were treated with 100–300 or 300–500 μm drug-eluting LC Beads (Biocompatibles, UK) preloaded with doxorubicin (range, 50–100 mg) for GI neuroendocrine tumor metastatic to the liver from June 2004 to June 2009 were included. CT and MRI were evaluated for progression using Response Evaluation Criteria In Solid Tumors (RECIST) or European Association for the Study of the Liver (EASL) criteria. Short-term (3 months) imaging response was determined and Kaplan–Meier survival curves were plotted. Results: Thirty-eight drug-eluting bead chemoembolization procedures were performed on 32 hepatic lobes, comprising 21 treatment cycles in 18 patients. All procedures were technically successful with two major complications (biliary injuries). At short-term follow-up (<3 months), 22 of 38 (58%) procedures and 10 of 21 (48%) treatment cycles produced an objective response (OR) with the remainder having stable disease (SD). At intermediate-term follow-up (mean, 445 days; range, 163–1247), 17 of 26 (65%) procedures and 8 of 14 (57%) treatment cycles produced an OR. Probability of progressing was approximately 52% at 1 year with a median time to progression of 419 days. Conclusions: Drug-eluting bead chemoembolization is a reasonable alternative to hepatic arterial embolization and chemoembolization for the treatment of metastatic neuroendocrine tumor to the liver.

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

    Directory of Open Access Journals (Sweden)

    Nina Koliha

    2016-02-01

    Full Text Available 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 analysis of EVs that carry surface markers recognized by both antibodies. This new method enables an easy screening of surface markers on populations of EVs. By combining different capture and detection antibodies, additional information on relative expression levels and potential vesicle subpopulations is gained. We also established a protocol to visualize individual EVs by stimulated emission depletion (STED microscopy. Thereby, markers on single EVs can be detected by fluorophore-conjugated antibodies. We used the multiplex platform and STED microscopy to show for the first time that NK cell–derived EVs and platelet-derived EVs are devoid of CD9 or CD81, respectively, and that EVs isolated from activated B cells comprise different EV subpopulations. We speculate that, according to our STED data, tetraspanins might not be homogenously distributed but may mostly appear as clusters on EV subpopulations. Finally, we demonstrate that EV mixtures can be separated by magnetic beads and analysed subsequently with the multiplex platform. Both the multiplex bead-based platform and STED microscopy revealed subpopulations of EVs that have been indistinguishable by most analysis tools used so far. We expect that an in-depth view on EV heterogeneity will contribute to our understanding of different EVs and functions.

  10. Development of simple immunoradiometric assays using avidin coupled to polystyrene beads as a common solid phase

    International Nuclear Information System (INIS)

    In this paper, we describe the preparation and application of avidin coupled polystyrene beads as a common solid phase for use in immunoradiometric assays (IRMAs). The assay system is based on two matched commercial monoclonal antibodies, of which, the capture antibody is biotinylated using biotinamidocaproate N-hydroxysuccinimide ester and the detection antibody is radiolabeled with 125I by conventional Chloramine-T method. Avidin was immobilized on the polystyrene beads through a primary coat of bovine serum albumin using glutaraldhyde activation method. Various factors, such as concentration of reagents, incubation time, etc. were optimised to obtain a simple assay protocol consisting of only two pipetting steps, namely, that of a mixture of the two labelled antibodies (radiolabelled and biotinylated) and of the standard or sample. The advantage of the Avidin-Biotin system is the improved sensitivity, economy of antibody and the possibility to use a common solid phase in assays for different analytes. Using the polystyrene beads along with the novel decanting device, it has been possible to achieve the convenience of the 'coated-tube' technology without the expensive automation necessary for large scale preparation of antibody coated tubes. This protocol has been successfully applied to Prolactin, LH and FSH assays. The sensitivity of the Prolactin assay is 8μIU/mL (0.3 ng/mL), that of the FSH assay is 1mIU/mL and that of the LH assay is 0.9 mIU/mL. The intra-assay and inter-assay variations were <10%. Shelf life of the avidin coupled beads was found to be about 8 months and that of the biotin labelled antibodies up to 18 months. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-08-26

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

  12. Development of the intelligent algorithm to control on-line bead height for robotic welding process

    OpenAIRE

    J.S. Son; Kim, I S; Lee, J.H.; Park, M. H.; Jeon, G S

    2013-01-01

    Purpose: The demand to increase productivity and quality, the shortage of skilled labour and strict health and safety requirements finally led to the development of the robotic welding process to deal with many problems of the welded fabrication. Many techniques were developed to control process parameters to get the optimal bead geometry during welding process by minimizes their magnitude in the affected area.Design/methodology/approach: The development of thermo mechanical mechanism in some...

  13. Modelling of the bead formation during multi pass hybrid laser/gas metal arc welding

    OpenAIRE

    Desmaison, Olivier; Guillemot, Gildas; Bellet, Michel

    2012-01-01

    A three dimensional finite element model has been developed to simulate weld bead formation in multi pass hybrid laser/gas metal arc welding. The model considers both a gas metal arc welding (GMAW) electrode and a laser beam moving along a workpiece. A Eulerian approach is used in which the interface between the metal and the surrounding gas or plasma is defined by a level set function. Therefore heat transfer boundary conditions are applied through a "Continuum Surface Force" model. An origi...

  14. Flexible Programming of Cell-Free Protein Synthesis Using Magnetic Bead-Immobilized Plasmids

    OpenAIRE

    Lee, Ka-Young; Lee, Kyung-Ho; Park, Ji-Woong; Kim, Dong-Myung

    2012-01-01

    The use of magnetic bead-immobilized DNA as movable template for cell-free protein synthesis has been investigated. Magnetic microbeads containing chemically conjugated plasmids were used to direct cell-free protein synthesis, so that protein generation could be readily programmed, reset and reprogrammed. Protein synthesis by using this approach could be ON/OFF-controlled through repeated addition and removal of the microbead-conjugated DNA and employed in sequential expression of different g...

  15. Prediction of bead area contact load at the tire-wheel interface using NASTRAN

    Science.gov (United States)

    Chen, C. H. S.

    1982-01-01

    The theoretical prediction of the bead area contact load at the tire wheel interface using NASTRAN is reported. The application of the linear code to a basically nonlinear problem results in excessive deformation of the structure and the tire-wheel contact conditions become impossible to achieve. A psuedo-nonlinear approach was adopted in which the moduli of the cord reinforced composite are increased so that the computed key deformations matched that of the experiment. Numerical results presented are discussed.

  16. A disposable bio-nano-chip using agarose beads for high performance immunoassays

    OpenAIRE

    Du, Nan; Chou, Jie; Kulla, Eliona; Floriano, Pierre N.; Christodoulides, Nicolaos; McDevitt, John T.

    2011-01-01

    This article reports on the fabrication of a disposable bio-nano-chip (BNC), a microfluidic device composed of polydimethylsiloxane (PDMS) and thiolene-based optical epoxy which is both cost-effective and suitable for high performance immunoassays. A novel room temperature (RT) bonding technique was utilized so as to achieve irreversible covalent bonding between PDMS and thiolene-based epoxy layers, while at the same time being compatible with the insertion of agarose bead sensors, selectivel...

  17. A tosyl-activated magnetic bead cellulose as solid support for sensitive protein detection

    Czech Academy of Sciences Publication Activity Database

    Yan, J.; Horák, Daniel; Lenfeld, Jiří; Hammond, M.; Kamali-Moghaddam, M.

    2013-01-01

    Roč. 167, č. 3 (2013), s. 235-240. ISSN 0168-1656 R&D Projects: GA ČR GAP503/10/0664; GA MŠk 7E12054 EU Projects: European Commission(XE) 259796 - DIATOOLS Institutional support: RVO:61389013 Keywords : bead cellulose * magnetic * protein detection Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.884, year: 2013

  18. Approaching prehistoric skills: experimental drilling in the context of bead manufacturing

    Directory of Open Access Journals (Sweden)

    Maria Gurova

    2013-12-01

    Full Text Available From the very Early Neolithic in the Balkans two categories of objects are recognized as having been involved in prehistoric drilling activities. The first is beads and other decorative and prestigious items made of bone, shell, pottery and various minerals. The second comprises toolkits of micro-perforators/borers found among the flint assemblages of several sites. This paper presents experiments in drilling different materials with the aim of testing several practical issues. A series of micro-borers were produced and used for manual and mechanical drilling (with a pump drill. Various samples (mainly prepared thin plates of minerals and rocks were used, ranging in hardness (on Mohs scale from 3 (marble, limestone, calcite to 6.5 (amazonite, nephrite. Biominerals were also used: aragonite (shells and apatite (bones. Actual bead production was approached by manufacturing 16 delicate beads of 5 different materials using fine sand and water abrasion. Though not conclusive, the experimental work was instructive in many of the parameters, procedures and technical details of prehistoric drilling.

  19. Enhanced levan production using chitin-binding domain fused levansucrase immobilized on chitin beads.

    Science.gov (United States)

    Chiang, Chung-Jen; Wang, Jen-You; Chen, Po-Ting; Chao, Yun-Peng

    2009-03-01

    Levan is a homopolymer of fructose which can be produced by the transfructosylation reaction of levansucrase (EC 2.4.1.10) from sucrose. In particular, levan synthesized by Zymomonas mobilis has found a wide and potential application in the food and pharmaceutical industry. In this study, the immobilization of Z. mobilis levansucrae (encoded by levU) was attempted for repeated production of levan. By fusion levU with the chitin-binding domain (ChBD), the hybrid protein was overproduced in a soluble form in Escherichia coli. After direct absorption of the protein mixture from E. coli onto chitin beads, levansucrase tagged with ChBD was found to specifically attach to the affinity matrix. Subsequent analysis indicated that the linkage between the enzyme and chitin beads was substantially stable. Furthermore, with 20% sucrose, the production of levan was enhanced by 60% to reach 83 g/l using the immobilized levansucrase as compared to that by the free counterpart. This production yield accounts for 41.5% conversion yield (g/g) on the basis of sucrose. After all, a total production of levan with 480 g/l was obtained by recycling of the immobilized enzyme for seven times. It is apparent that this approach offers a promising way for levan production by Z. mobilis levansucrase immobilized on chitin beads. PMID:19018526

  20. Characterization of calcium alginate beads of 5-fluorouracil for colon delivery

    Directory of Open Access Journals (Sweden)

    Patel Hetal

    2008-01-01

    Full Text Available A multiparticulate system combining pH-sensitive property and specific biodegradability for colon targeted delivery of 5-fluorouracil (5-FU was examined. The purpose of this study was to prepare and evaluate the colon-specific alginate beads of 5-FU for the treatment of colon cancer. Calcium alginate beads were prepared by extruding 5-FU loaded alginate solution to calcium chloride solution, and gelled spheres were formed instantaneously by ionotropic gelation reaction using different ratios of FU and alginate, alginate and calcium chloride, stirring speeds (500-1500 rpm, and reaction time. The core beads were coated with Eudragit S-100 to prevent drug release in the stomach and provide controlled dissolution of enteric coat in the small intestine and maximum drug release in the colon. Morphology and surface characteristics of the formulation were determined by scanning electron microscopy. In vitro drug release studies were performed in conditions simulating stomach to colon transit. No significant release was observed at acidic pH, however, when it reached the pH where Eudragit S-100 starts to dissolve, drug release was observed. Also, release of drug was found to be higher in presence of rat caecal content.

  1. Ndel1-derived peptides modulate bidirectional transport of injected beads in the squid giant axon

    Directory of Open Access Journals (Sweden)

    Michal Segal

    2012-01-01

    Bidirectional transport is a key issue in cellular biology. It requires coordination between microtubule-associated molecular motors that work in opposing directions. The major retrograde and anterograde motors involved in bidirectional transport are cytoplasmic dynein and conventional kinesin, respectively. It is clear that failures in molecular motor activity bear severe consequences, especially in the nervous system. Neuronal migration may be impaired during brain development, and impaired molecular motor activity in the adult is one of the hallmarks of neurodegenerative diseases leading to neuronal cell death. The mechanisms that regulate or coordinate kinesin and dynein activity to generate bidirectional transport of the same cargo are of utmost importance. We examined how Ndel1, a cytoplasmic dynein binding protein, may regulate non-vesicular bidirectional transport. Soluble Ndel1 protein, Ndel1-derived peptides or control proteins were mixed with fluorescent beads, injected into the squid giant axon, and the bead movements were recorded using time-lapse microscopy. Automated tracking allowed for extraction and unbiased analysis of a large data set. Beads moved in both directions with a clear bias to the anterograde direction. Velocities were distributed over a broad range and were typically slower than those associated with fast vesicle transport. Ironically, the main effect of Ndel1 and its derived peptides was an enhancement of anterograde motion. We propose that they may function primarily by inhibition of dynein-dependent resistance, which suggests that both dynein and kinesin motors may remain engaged with microtubules during bidirectional transport.

  2. Gold Bead Implantation in Acupoints for Coxofemoral Arthrosis in Dogs: Method Description and Adverse Effects

    Directory of Open Access Journals (Sweden)

    Lars Moe

    2012-09-01

    Full Text Available Gold bead implantation has been used for years as an alternative method to improve function in chronic joint disease both in humans and dogs. The aims of the present study were to describe the technique of implanting 24-karat gold beads around the hip joints of dogs with chronic hip dysplasia, and to record any side effects or complications of such treatment. A prospective placebo-controlled double-blinded clinical trial was performed. Eighty dogs were randomly allocated to treatment or placebo, with 38 in the gold implantation group and 42 in the placebo group, and followed intensely for six months. The implantation technique was simple to perform, using fluoroscopy and with the dogs under inhalation anesthesia for about 30 minutes. Adverse effects, measured as pain or discomfort, were seen for a period of up to four weeks in 15 of the dogs in the gold implantation group, compared to six dogs in the placebo group. During implantation, a technical difficulty occurred as 82% of the dogs showed leakage of blood and/or synovia from the needles. The dogs in the gold implantation group were radiographed 18 months later. Of the 30 dogs that were radiographed at both inclusion and 24 months, 80% (24 dogs showed a deterioration of the coxofemoral arthrosis, the other six had stable disease evaluated by radiography. Migration of gold beads was only observed in one dog.

  3. Glycan Analysis by Reversible Reaction to Hydrazide Beads and Mass Spectrometry

    Science.gov (United States)

    Yang, Shuang J.; Zhang, Hui

    2016-01-01

    Investigation into glycoproteins and their associated glycans is the key to understanding the function of glycoproteins in biological pathways and disease development. Current methods for glycan analysis are generally based on multiple preparation processes to separate glycans from proteins and other molecules prior to analysis. During the multistep purification processes, glycans are continuously lost and the procedure increases the difficulty for accurate quantitative analysis of glycans. Here we describe the development of a novel technique, which uses hydrazide beads to capture glycans. It is based on the conjugation of glycans to hydrazide beads through the formation of reversible hydrazone, washing out unbound nonglycans, then releasing captured glycans by acids. The results showed that the glycans were able to be isolated from concatenate peptides by using hydrazide beads. This technique was also applied to the analysis of glycans from sera sample. The integrated capture-release on the solid-phase simplifies the procedure for glycan preparation from a complex mixture and can be a powerful tool for glycan analysis. PMID:22304307

  4. An integrated microfluidic biochemical detection system for protein analysis with magnetic bead-based sampling capabilities.

    Science.gov (United States)

    Choi, Jin-Woo; Oh, Kwang W; Thomas, Jennifer H; Heineman, William R; Halsall, H Brian; Nevin, Joseph H; Helmicki, Arthur J; Henderson, H Thurman; Ahn, Chong H

    2002-02-01

    This paper presents the development and characterization of an integrated microfluidic biochemical detection system for fast and low-volume immunoassays using magnetic beads, which are used as both immobilization surfaces and bio-molecule carriers. Microfluidic components have been developed and integrated to construct a microfluidic biochemical detection system. Magnetic bead-based immunoassay, as a typical example of biochemical detection and analysis, has been successfully performed on the integrated microfluidic biochemical analysis system that includes a surface-mounted biofilter and electrochemical sensor on a glass microfluidic motherboard. Total time required for an immunoassay was less than 20 min including sample incubation time, and sample volume wasted was less than 50 microl during five repeated assays. Fast and low-volume biochemical analysis has been successfully achieved with the developed biofilter and immunosensor, which is integrated to the microfluidic system. Such a magnetic bead-based biochemical detection system, described in this paper, can be applied to protein analysis systems. PMID:15100857

  5. Specific capture of the hydrolysate on magnetic beads for sensitive detecting plant vacuolar processing enzyme activity.

    Science.gov (United States)

    Zhou, Jun; Cheng, Meng; Zeng, Lizhang; Liu, Weipeng; Zhang, Tao; Xing, Da

    2016-05-15

    Conventional plant protease detection always suffers from high background interference caused by the complex coloring metabolites in plant cells. In this study, a bio-modified magnetic beads-based strategy was developed for sensitive and quantitative detection of plant vacuolar processing enzyme (VPE) activity. Cleavage of the peptide substrate (ESENCRK-FITC) after asparagine residue by VPE resulted in the 2-cyano-6-amino-benzothiazole (CABT)-functionalized magnetic beads capture of the severed substrate CRK-FITC via a condensation reaction between CABT and cysteine (Cys). The catalytic activity was subsequently obtained by the confocal microscopy imaging and flow cytometry quantitative analysis. The sensor system integrated advantages of (i) the high efficient enrichment and separation capabilities of magnetic beads and (ii) the catalyst-free properties of the CABT-Cys condensation reaction. It exhibited a linear relationship between the fluorescence signal and the concentration of severed substrate in the range of 10-600 pM. The practical results showed that, compared with normal growth conditions, VPE activity was increased by 2.7-fold (307.2 ± 25.3 μM min(-1)g(-1)) upon cadmium toxicity stress. This platform effectively overcame the coloring metabolites-caused background interference, showing fine applicability for the detection of VPE activity in real samples. The strategy offers great sensitivity and may be further extended to other protease activity detection. PMID:26797250

  6. Gold Bead Implantation in Acupoints for Coxofemoral Arthrosis in Dogs: Method Description and Adverse Effects.

    Science.gov (United States)

    Jæger, Gry T; Stigen, Øyvind; Devor, Morten; Moe, Lars

    2012-01-01

    Gold bead implantation has been used for years as an alternative method to improve function in chronic joint disease both in humans and dogs. The aims of the present study were to describe the technique of implanting 24-karat gold beads around the hip joints of dogs with chronic hip dysplasia, and to record any side effects or complications of such treatment. A prospective placebo-controlled double-blinded clinical trial was performed. Eighty dogs were randomly allocated to treatment or placebo, with 38 in the gold implantation group and 42 in the placebo group, and followed intensely for six months. The implantation technique was simple to perform, using fluoroscopy and with the dogs under inhalation anesthesia for about 30 minutes. Adverse effects, measured as pain or discomfort, were seen for a period of up to four weeks in 15 of the dogs in the gold implantation group, compared to six dogs in the placebo group. During implantation, a technical difficulty occurred as 82% of the dogs showed leakage of blood and/or synovia from the needles. The dogs in the gold implantation group were radiographed 18 months later. Of the 30 dogs that were radiographed at both inclusion and 24 months, 80% (24 dogs) showed a deterioration of the coxofemoral arthrosis, the other six had stable disease evaluated by radiography. Migration of gold beads was only observed in one dog. PMID:26487031

  7. Effect of bead and illustrations models on high school students' achievement in molecular genetics

    Science.gov (United States)

    Rotbain, Yosi; Marbach-Ad, Gili; Stavy, Ruth

    2006-05-01

    Our main goal in this study was to explore whether the use of models in molecular genetics instruction in high school can contribute to students' understanding of concepts and processes in genetics. Three comparable groups of 11th and 12th graders participated: The control group (116 students) was taught in the traditional lecture format, while the others received instructions which integrated a bead model (71 students), or an illustration model (71 students). Similar instructions and the same guiding questions accompanied the two models. We used three instruments: a multiple-choice and an open-ended written questionnaire, as well as personal interviews. Five of the multiple-choice questions were also given to students before receiving their genetics instruction (pretest). We found that students who used one of the two types of models improved their knowledge in molecular genetics compared to the control group. However, the open-ended questions revealed that bead model activity was significantly more effective than illustration activity. On the basis of these findings we conclude that, though it is advisable to use a three-dimensional model, such as the bead model, engaging students in activities with illustrations can still improve their achievement in comparison to traditional instruction.

  8. Preparation of metal-resistant immobilized sulfate reducing bacteria beads for acid mine drainage treatment.

    Science.gov (United States)

    Zhang, Mingliang; Wang, Haixia; Han, Xuemei

    2016-07-01

    Novel immobilized sulfate-reducing bacteria (SRB) beads were prepared for the treatment of synthetic acid mine drainage (AMD) containing high concentrations of Fe, Cu, Cd and Zn using up-flow anaerobic packed-bed bioreactor. The tolerance of immobilized SRB beads to heavy metals was significantly enhanced compared with that of suspended SRB. High removal efficiencies of sulfate (61-88%) and heavy metals (>99.9%) as well as slightly alkaline effluent pH (7.3-7.8) were achieved when the bioreactor was fed with acidic influent (pH 2.7) containing high concentrations of multiple metals (Fe 469 mg/L, Cu 88 mg/L, Cd 92 mg/L and Zn 128 mg/L), which showed that the bioreactor filled with immobilized SRB beads had tolerance to AMD containing high concentrations of heavy metals. Partially decomposed maize straw was a carbon source and stabilizing agent in the initial phase of bioreactor operation but later had to be supplemented by a soluble carbon source such as sodium lactate. The microbial community in the bioreactor was characterized by denaturing gradient gel electrophoresis (DGGE) and sequencing of partial 16S rDNA genes. Synergistic interaction between SRB (Desulfovibrio desulfuricans) and co-existing fermentative bacteria could be the key factor for the utilization of complex organic substrate (maize straw) as carbon and nutrients source for sulfate reduction. PMID:27058913

  9. A bead on a hoop rotating about a horizontal axis: a 1-D ponderomotive trap

    CERN Document Server

    Johnson, Andrew K

    2009-01-01

    We describe a simple mechanical system that operates as a ponderomotive particle trap, consisting of a circular hoop and a frictionless bead, with the hoop rotating about a horizontal axis lying in the plane of the hoop. The bead in the frame of the hoop is thus exposed to an effective sinusoidally-varying gravitational field. This field's component along the hoop is a zero at the top and bottom. In the same frame, the bead experiences a time-independent centrifugal force that is zero at the top and bottom as well. The system is analyzed in the ideal case of small displacements from the minimum, and the motion of the particle is shown to satisfy the Mathieu equation. In the particular case that the axis of rotation is tangential to the hoop, the system is an exact analog for the rf Paul ion trap. Various complicating factors such as anharmonic terms, friction and noise are considered. A working model of the proposed system has been constructed, using a ball-bearing rolling in a tube along the outside of a sec...

  10. Evidence of protein-free homology recognition in magnetic bead force–extension experiments

    Science.gov (United States)

    (O’) Lee, D. J.; Danilowicz, C.; Rochester, C.; Prentiss, M.

    2016-01-01

    Earlier theoretical studies have proposed that the homology-dependent pairing of large tracts of dsDNA may be due to physical interactions between homologous regions. Such interactions could contribute to the sequence-dependent pairing of chromosome regions that may occur in the presence or the absence of double-strand breaks. Several experiments have indicated the recognition of homologous sequences in pure electrolytic solutions without proteins. Here, we report single-molecule force experiments with a designed 60 kb long dsDNA construct; one end attached to a solid surface and the other end to a magnetic bead. The 60 kb constructs contain two 10 kb long homologous tracts oriented head to head, so that their sequences match if the two tracts fold on each other. The distance between the bead and the surface is measured as a function of the force applied to the bead. At low forces, the construct molecules extend substantially less than normal, control dsDNA, indicating the existence of preferential interaction between the homologous regions. The force increase causes no abrupt but continuous unfolding of the paired homologous regions. Simple semi-phenomenological models of the unfolding mechanics are proposed, and their predictions are compared with the data. PMID:27493568

  11. Ion-imprinted chitosan gel beads for selective adsorption of Ag⁺ from aqueous solutions.

    Science.gov (United States)

    Zhang, Meng; Helleur, Robert; Zhang, Yan

    2015-10-01

    In this study, the Ag(+)-imprinted chitosan gel beads were synthesized to selectively adsorb Ag(+) from bimetallic aqueous solutions containing the same molar concentration of Ag(+) and Cu(2+). The Ag(+)-imprinting not only helps to achieve extremely high selectivity of Ag(+), but also enhances the uptake capacity of the target Ag(+) by protecting some amine groups, the primary binding sites of metal ions from cross-linking. The maximum uptake of Ag(+) by the ion-imprinted chitosan beads was found to be 89.20 mg g(-1) at 25.0°C with an initial Ag(+) concentration of 352.95 mg L(-1) and the biosorbent dosage of 1.0 g L(-1). The adsorption equilibrium and kinetics of Ag(+) by the ion-imprinted chitosan beads can be better described by Langmuir isotherm and the intraparticle diffusion model. FTIR and XPS analyses suggested that amine functional groups involve the binding of Ag(+) via complexation at higher solution pH (3.0 ≤ pH ≤ 5.0) and ion exchange at lower solution pH (1.0 ≤ pH < 3.0). PMID:26076618

  12. Selective doxorubicin drug eluting beads chemoembolization of hypovascular hepatocellular carcinoma using cone beam computed tomography

    Directory of Open Access Journals (Sweden)

    Naveen Kalra

    2012-01-01

    Full Text Available Hepatocellular carcinoma (HCC of the liver is the third most common cause of cancer-related deaths in the world. Only one-third of patients with HCC are suitable candidates for hepatic resection. Transarterial chemoembolization (TACE is performed in unresectable HCC. Drug-eluting beads (DEB TACE is a modification of TACE, in which doxorubicin beads are used as embolizing material.These beads deliver the drug and embolize the vessels; however, it carries the risk of non-target embolization and it is difficult in cases with absent arterial blush on digital subtraction angiography (DSA. This is resolved using C-arm cone-beam computed tomography in the DSA suite. It identifies the tumor-feeding vessels, their area of supply, and differentiates between tumor and normal liver parenchyma. In addition, it is very useful in the embolization of hypovascular HCC. It helps and guides the radiologist in performing TACE effectively and also prevents non-target embolization of normal liver parenchyma.

  13. Selective doxorubicin drug eluting beads chemoembolization of hypovascular hepatocellular carcinoma using cone beam computed tomography.

    Science.gov (United States)

    Kalra, Naveen; Mahajan, Divyesh; Chawla, Yogesh; Khandelwal, N

    2012-10-01

    Hepatocellular carcinoma (HCC) of the liver is the third most common cause of cancer-related deaths in the world. Only one-third of patients with HCC are suitable candidates for hepatic resection. Transarterial chemoembolization (TACE) is performed in unresectable HCC. Drug-eluting beads (DEB) TACE is a modification of TACE, in which doxorubicin beads are used as embolizing material. These beads deliver the drug and embolize the vessels; however, it carries the risk of non-target embolization and it is difficult in cases with absent arterial blush on digital subtraction angiography (DSA). This is resolved using C-arm cone-beam computed tomography in the DSA suite. It identifies the tumor-feeding vessels, their area of supply, and differentiates between tumor and normal liver parenchyma. In addition, it is very useful in the embolization of hypovascular HCC. It helps and guides the radiologist in performing TACE effectively and also prevents non-target embolization of normal liver parenchyma. PMID:23833414

  14. Comparative study between yeasts immobilized on alumina beads and on membranes prepared by two routes

    Directory of Open Access Journals (Sweden)

    Kiyohara Pedro K.

    2003-01-01

    Full Text Available Alumina channeled beads and rough surface membranes prepared from aqueous sols of fibrillar pseudoboehmite are able to immobilize yeasts for ethanol fermentation of sugar solutions. This paper describes comparative results of assays carried out with yeasts immobilized onto alpha-alumina beads and membranes prepared under two different conditions of processing and firing. The fermentation tests evaluated by the decrease of fermentable sugars, referred as Brix degrees per hour, indicated that the yeasts immobilized on beads had similar performance, probably because their surfaces, even being morphologically different, presented the same value of open porosity. One type of membrane (asymmetrical; precursor: pseudoboehmite; firing temperature 1,150ºC; crystal structure; alpha-alumina had better performance than the other type (asymmetrical; precursor: fibrillar pseudoboehmite plus aluminum hydroxiacetate mixture; 1,150ºC; alpha-alumina because the yeast cells entered into their porous interior through the surface slits, were immobilized and their growth was easier than on the external surface.

  15. Porous Bead-Based Diagnostic Platforms: Bridging the Gaps in Healthcare

    Directory of Open Access Journals (Sweden)

    John McDevitt

    2012-11-01

    Full Text Available Advances in lab-on-a-chip systems have strong potential for multiplexed detection of a wide range of analytes with reduced sample and reagent volume; lower costs and shorter analysis times. The completion of high-fidelity multiplexed and multiclass assays remains a challenge for the medical microdevice field; as it struggles to achieve and expand upon at the point-of-care the quality of results that are achieved now routinely in remote laboratory settings. This review article serves to explore for the first time the key intersection of multiplexed bead-based detection systems with integrated microfluidic structures alongside porous capture elements together with biomarker validation studies. These strategically important elements are evaluated here in the context of platform generation as suitable for near-patient testing. Essential issues related to the scalability of these modular sensor ensembles are explored as are attempts to move such multiplexed and multiclass platforms into large-scale clinical trials. Recent efforts in these bead sensors have shown advantages over planar microarrays in terms of their capacity to generate multiplexed test results with shorter analysis times. Through high surface-to-volume ratios and encoding capabilities; porous bead-based ensembles; when combined with microfluidic elements; allow for high-throughput testing for enzymatic assays; general chemistries; protein; antibody and oligonucleotide applications.

  16. Development of the intelligent algorithm to control on-line bead height for robotic welding process

    Directory of Open Access Journals (Sweden)

    J.S. Son

    2013-06-01

    Full Text Available Purpose: The demand to increase productivity and quality, the shortage of skilled labour and strict health and safety requirements finally led to the development of the robotic welding process to deal with many problems of the welded fabrication. Many techniques were developed to control process parameters to get the optimal bead geometry during welding process by minimizes their magnitude in the affected area.Design/methodology/approach: The development of thermo mechanical mechanism in some techniques is not fully understood. To solve this problem, we have carried out the sequential experiment based on a Taguchi method and identified the various problems that result from the robotic GMA welding process.Findings: To characterize the GMA welding process and establish guidelines for the most effective joint design. Also using multiple regression analysis with the help of a standard statistical package program, SPSS, on an IBM-compatible PC, a quadratic model has been developed for on-line control which studies the influence of process parameters on bead height and compares their influences on the bead height to see which one of process parameters is most affecting. Originality/value: This model developed has been employed the prediction of optimal process parameters and assisted in the generation of process control algorithms.

  17. Sorption of Sr-85 and Am-241 from liquid radioactive wastes by alginate beads

    Directory of Open Access Journals (Sweden)

    Oszczak Agata

    2015-12-01

    Full Text Available The paper reports the adsorption of strontium(II and americium(III from aqueous solutions onto calcium alginate (CaA, barium alginate (BaA and strontium alginate (SrA beads. Adsorption process was studied in batch experiments as a function of the initial pH of the solution and the contact time. All sorbents were examined by the termogravimetric analysis (TG. Laboratory obtained spherical beads of CaA, BaA and SrA seem to be good metal sorbents from liquid radioactive wastes. A contact time of about 4 h and neutral pH of the initial aqueous solution have been proposed to be optimum conditions for Sr-85 and Am-241 removal from the contaminated solutions using alginate sorbents. Laboratory obtained beads of CaA, BaA and SrA are characterized by the decontamination factor (DF equal to 85% for Sr(II and 90% for Am(III.

  18. Size-dependent self-assembly of submicron/nano beads-protein conjugates for construction of a protein nanoarray

    International Nuclear Information System (INIS)

    A protein nanoarray is created when submicro and nano beads, varying in their size and each conjugated with different proteins, self-assemble to specific locations depending on the diameter matching the surface electron beam patterns created. Protein binding is confirmed from the fluorescence attenuation of the beads upon antigen-antibody binding on the bead surface. This method, called size-dependent self-assembly, allows control of the location of each type of bead, and thus, control of the location of multiple proteins. It provides fast multi-component patterning with a high binding resolution, which can be detected using a fluorescent light microscope. This method is developed to be a simple stand-alone tool for analysis of protein interactions. In addition, it has the potential to be used in conjunction with other protein analysis methods, such as enzyme-linked immunosorbent assay (ELISA) and atomic force microscopy (AFM).

  19. Encapsulating betalains from Opuntia ficus-indica fruits by ionic gelation: Pigment chemical stability during storage of beads.

    Science.gov (United States)

    Otálora, María Carolina; Carriazo, José Gregorio; Iturriaga, Laura; Osorio, Coralia; Nazareno, Mónica Azucena

    2016-07-01

    Betalain encapsulation was performed by ionic gelation as a stabilization strategy for these natural pigments. Betalains were extracted from purple cactus fruits and encapsulated in calcium-alginate and in combination of calcium alginate and bovine serum albumin. Beads were characterised by scanning electron microscopy and thermal analysis using differential scanning calorimetry and thermogravimetry. Moisture sorption isotherms were determined. Bead morphology was affected by matrix composition. Pigments storage stability was evaluated at different equilibrium relative humidity and temperatures. Pigment composition of beads was determined by HPLC-MS-MS and degradation products were also analysed after storage; betalamic acid being the major one. Both types of matrices protected the encapsulated pigments, being their storage stability better at low relative humidity than that of the non-encapsulated control material. Antiradical activities of beads were proportional to remaining betalain contents. At high relative humidity, there was no protection and low storage stability was observed in the samples. PMID:26920307

  20. Solid phase extraction of penicillins from milk by using sacrificial silica beads as a support for a molecular imprint

    International Nuclear Information System (INIS)

    We have prepared molecularly imprinted beads with molecular recognition capability for target molecules containing the penicillanic acid substructure. They were prepared by (a) grafting mesoporous silica beads with 6-aminopenicillanic acid as the mimic template, (b) filling the pores with a polymerized mixture of methacrylic acid and trimethylolpropane trimethacrylate, and (c) removing the silica support with ammonium fluoride. The resulting imprinted beads showed good molecular recognition capability for various penicillanic species, while antibiotics such as cephalosporins or chloramphenicol were poorly recognized. The imprinted beads were used to extract penicillin V, nafcillin, oxacillin, cloxacillin and dicloxacillin from skimmed and deproteinized milk in the concentration range of 5–100 μg·L−1. The extracts were then analyzed by micellar electrokinetic chromatography by applying reverse polarity staking as an in-capillary preconcentration step, and this resulted in a fast and affordable method within the MRL levels, characterized by minimal pretreatment steps and recoveries of 64–90 %. (author)

  1. Application of Pcvd Process to Uniform Coating of TiO2 Thin Films on Polypropylene Beads

    Science.gov (United States)

    Kim, Dong-Joo; Pham, Hung Cuong; Kim, Kyo-Seon

    The growth of the TiO2 thin films coated on the polypropylene beads was analyzed experimentally in a rotating cylindrical plasma chemical vapor deposition (PCVD) reactor. The precursors for the thin films were generated by plasma reactions, and they deposited on the polypropylene beads to become the uniform thin films. The TiO2 thin films grow more quickly on the polypropylene beads by increasing the mass flow rate of TTIP, or the rotation speed of the reactor. The smaller number of polypropylene beads in the reactor increases the growth rate of the thin films. The high-quality TiO2 thin films can be coated on particles uniformly by using the rotating cylindrical PCVD process. The particles coated with high-quality TiO2 thin films can be applied to the removal of air and water pollutants by a photodegradation reaction of TiO2.

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

    OpenAIRE

    Tripathi, G.; Singh, S

    2010-01-01

    "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 ...

  3. l-Arginine grafted alginate hydrogel beads: A novel pH-sensitive system for specific protein delivery

    Directory of Open Access Journals (Sweden)

    Mohamed S. Mohy Eldin

    2015-05-01

    Full Text Available Novel pH-sensitive hydrogels based on l-arginine grafted alginate (Arg-g-Alg hydrogel beads were synthesized and utilized as a new carrier for protein delivery (BSA in specific pH media. l-arginine was grafted onto the polysaccharide backbone of virgin alginate via amine functions. Evidences of grafting of alginate were extracted from FT-IR and thermal analysis, while the morphological structure of Arg-g-Alg hydrogel beads was investigated by SEM photographs. Factors affecting on the grafting process e.g. l-arginine concentration, reaction time, reaction temperature, reaction pH, and crosslinking conditions, have been studied. Whereas, grafting efficiency of each factor was evaluated. Grafting of alginate has improved both thermal and morphological properties of Arg-g-Alg hydrogel beads. The swelling behavior of Arg-g-Alg beads was determined as a function of pH and compared with virgin calcium alginate beads. The cumulative in vitro release profiles of BSA loaded beads were studied at different pHs for simulating the physiological environments of the gastrointestinal tract. The amount of BSA released from neat alginate beads at pH 2 was almost 15% after 5 h, while the Arg-g-Alg beads at the same conditions were clearly higher than 45%, then it increased to 90% at pH 7.2. Accordingly, grafting of alginate has improved its release profile behavior particularly in acidic media. The preliminary results clearly suggested that the Arg-g-Alg hydrogel may be a potential candidate for polymeric carrier for oral delivery of protein or drugs.

  4. Applying the Taguchi Design for Optimized Formulation of Sustained Release Gliclazide Chitosan Beads: An In Vitro/In Vivo Study

    OpenAIRE

    Varshosaz, J.; Tavakoli, N.; Minayian, M.; Rahdari, N.

    2009-01-01

    Gliclazide is a second generation of hypoglycemic sulfonylurea and acts selectively on pancreatic β cell to control diabetes mellitus. The objective of this study was to produce a controlled release system of gliclazide using chitosan beads. Chitosan beads were produced by dispersion technique using tripolyphosphate (TPP) as gelating agent. The effects of process variables including chitosan molecular weight, concentration of chitosan and TPP, pH of TPP, and cross-linking time after addition ...

  5. Optimization of Weld Bead Parameters of Nickel Based Overlay Deposited by Plasma Transferred Arc Surfacing with Adequacy Test

    OpenAIRE

    Bhaskarananda Dasgupta; Pinaky Bhadury

    2014-01-01

    Plasma Transferred Arc surfacing is a kind of Plasma Transferred Arc Welding process. Plasma Transferred Arc surfacing (PTA) is increasingly used in applications where enhancement of wear, corrosion and heat resistance of materials surface is required. The shape of weld bead geometry affected by the PTA Welding process parameters is an indication of the quality of the weld. In this paper the analysis and optimization of weld bead parameters, during deposition of a Nickel based...

  6. Sustained release of diltiazem hydrochloride from cross-linked biodegradable IPN hydrogel beads of pectin and modified xanthan gum

    OpenAIRE

    Giri, T. K.; Choudhary, C.; Alexander, A.; Ajazuddin,; Badwaik, H.; Tripathy, M.; Tripathi, D. K.

    2013-01-01

    Interpenetrating polymer network hydrogel beads of pectin and sodium carboxymethyl xanthan were prepared by ionotropic gelation with Al +3 ions and covalent cross-linking with glutaraldehyde for sustained delivery of diltiazem hydrochloride. Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning colorimetry and scanning electron microscopy were used to characterise the hydrogel beads. The swelling of the hydrogel and the release of drug were relatively low in pH 1.2...

  7. A Mössbauer study of the chemical stability of iron oxide nanoparticles in PMMA and PVB beads

    DEFF Research Database (Denmark)

    Chen, Wei; Mørup, Steen; Hansen, Mikkel Fougt;

    2008-01-01

    We have prepared magnetic beads consisting of iron oxide nanoparticles in a polymethyl methacrylate (PMMA) and a polyvinyl butyral (PVB) matrix. High-field Mossbauer studies show that the particles have an almost perfect collinear spin structure and magnetization measurements show that they are s...... transformed to maghemite. The PVB beads are hydrophilic and biocompatible and are therefore well suited for applications in medicine and biology....

  8. Correlations of coronary plaque wall thickness with wall pressure and wall pressure gradient: a representative case study

    OpenAIRE

    Liu Biyue; Zheng Jie; Bach Richard; Tang Dalin

    2012-01-01

    Abstract Background There are two major hemodynamic stresses imposed at the blood arterial wall interface by flowing blood: the wall shear stress (WSS) acting tangentially to the wall, and the wall pressure (WP) acting normally to the wall. The role of flow wall shear stress in atherosclerosis progression has been under intensive investigation, while the impact of blood pressure on plaque progression has been under-studied. Method The correlations of wall thickness (WT) with wall pressure (WP...

  9. Forward Wall Detector

    International Nuclear Information System (INIS)

    The Forward Wall Detector is designed to identify projectile like fragments from heavy ion reactions at CELSIUS storage ring in Uppsala, Sweden. The FWD consist of 96 detection modules covering azimuthal angle from 3.9o to 11.7o with efficiency of 81%. The detection module can be either of phoswitch type (10 mm fast plastic + 80 mm CsI(Tl)) or standard ΔE-E telescope (750 μm Si + 88 mm CsI(Tl)). It is expected to have charge identification up to Z=18, mass resolution for H and He isotopes and energy resolution ∼ 8%. (author)

  10. A radioimmunoassay for lignin in plant cell walls

    International Nuclear Information System (INIS)

    Lignin detection and determination in herbaceous tissue requires selective, specific assays which are not currently available. A radioimmunoassay (RIA) was developed to study lignin metabolism in these tissues. A β-aryl ether lignin model compound was synthesized, linked to keyhole limpet hemocyanin using a water-soluble carbodiimide, and injected into rabbits. The highest titer of the antiserum obtained was 34 ηg/mL of model derivatized BSA. An in vitro system was developed to characterize the RIA. The model compound was linked to amino activated polyacrylamide beads to mimic lignin in the cell walls. 125I Radiolabelled protein A was used to detect IgG antibody binding. The RIA was shown in the in vitro system to exhibit saturable binding. The amount of antibody bound decreased when the serum was diluted. Immunoelectrophoresis and competitive binding experiments confirmed that both aromatic rings of the lignin model compound had been antigenic. Chlorogenic acid, a phenolic known to be present in plant cells, did not compete for antibody binding. The RIA was used to measure lignin in milled plant samples and barley seedlings. Antiserum binding to wheat cell walls and stressed barley segments was higher than preimmune serum binding. Antibody binding to stressed barley tissue decreased following NaClO2 delignification. The RIA was found to be less sensitive than expected, so several avenues for improving the method are discussed

  11. 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

  12. Solid phase extraction of actinides using polymeric beads impregnated with TODGA

    International Nuclear Information System (INIS)

    Separation of minor actinides from HLW is necessary prior to the vitrification of the latter in the glass matrix. A number of solvent extraction processes such as TRUEX, TRPO and DIAMEX have been developed which employed CMPO, TRPO and DMDBTDMA, respectively as the extractants for minor actinides. Recently, TODGA has been found to be most efficient extractant of minor actinides due to its ability to form stronger complexes. In view of large solvent inventory in the solvent extraction methods, extraction chromatography based separation methods which utilize very small amounts of the extractant can be used as an alternative technique. However, the main drawback of such separation methods is slow deterioration of the uptake efficiency due to leaching out of the extractants. Therefore, use of extractant blended polymeric beads can have faster metal ion uptake while having longer reusability of the beads. There have been several reports on the preparation of polymeric beads for metal ion sorption. In present paper, uptake of actinide ion by polymeric beads containing four different proportions of TODGA was studied. The polymeric beads were used for the experiments involving the uptake of Am(III) at different nitric acid concentration at tracer scale and the results are listed. It was found that Kd values were in the range of 1x104 to 2x104 in the given range of acidity. The results are in sharp contrast with the results obtained with the extraction chromatographic resin used in a previous study. We have also carried out actinide ion uptake studies involving the kinetics of metal ion sorption, adsorption isotherm and column studies. The metal ion sorption capacities for Eu (III) were found to be 6.6(±0.3), 9.1 (±0.5), 20.4 (±1.2), and 22.3(±1.4), for the above four resins, respectively. Column studies were also carried out using 6 ml of bed volume, columns containing about 0.6 to 0.7 gm of resin. The breaks through profiles were obtained using 0.01 M EDTA as the

  13. Archaeometric study of glass beads from the 2nd century BC cemetery of Numantia

    Directory of Open Access Journals (Sweden)

    García Heras, Manuel

    2003-06-01

    Full Text Available Recent archaeologícalf ieldwork undertaken in the Celtiberian cremation necropolis of Numantia (Soria, Spain has provided a group of glass beads from the 2nd century BC. Such glass beads were part, together with other metallic and ceramic items, of the offerings deposited with the dead. They are ring-shaped in typology and deep-blue, amber, or semitransparent white in colour. This paper reports results derived from the chemical and microstructural characterization carried out on a representative sample set of this group of beads. The main goal of the research was to find out about their production technology to explore their probable provenance. In addítion, corrosion mechanisms were also assessed to determine the influence of crematíon on the beads' structure. The resulting data suggest that these blue and amber beads were made using soda-lime silicate glass, whereas semi-transparent white ones were manufactured from alumino-silicate glass. It has also determined that some transition metal oxides were used as chromophores, as well as lead oxide for decoration.

    La reciente excavación de la necrópolis celtibérica de Numancia (Garray, Soria ha permitido recuperar un conjunto de cuentas de vidrio del siglo II a.C. Las cuentas, junto con otros objetos de metaly cerámica, formaban parte de las ofrendas depositadas con el difunto, siendo de tipología anular y coloreadas en azul oscuro, ambar y blanco semitransparente. Este trabajo presenta los resultados obtenidos en la caracterización química y microestructural de una muestra representativa de este conjunto. El objetivo principal de la investigación consistió en recabar información sobre su tecnología de manufactura y evaluar su posible procedencia. Asimismo, también se investigaron sus mecanismos de corrosión para determinar si la cremación había inducido cambios en su estructura. Los resultados indican que las cuentas azules y ámbar se realizaron con vidrio de silicato s

  14. Bioinspired methodology for preparing magnetic responsive chitosan beads to be integrated in a tubular bioreactor for biomedical applications

    International Nuclear Information System (INIS)

    Magnetic responsive chitosan beads were prepared using a methodology inspired by the rolling of water droplets over lotus leaves. Liquid precursors containing chitosan and magnetic microparticles were dispensed in the form of spherical droplets and crosslinked with genipin over synthetic superhydrophobic surfaces. Scanning electronic microscopy, histology and micro-computed tomography were employed to characterize the structure of the prepared composite beads and the inner distribution of the magnetic particles. Cellular metabolic activity tests showed that fibroblasts-like (L929 cell line) can adhere and proliferate on the prepared chitosan beads. We hypothesize that such spherical biomaterials could be integrated in a new concept of tubular bioreactor. The magnetic beads can be immobilized by an external magnetic field at specific positions and may be transported along the bioreactor by the drag of the culture medium flow. The system behavior was also studied through numerical modeling, which allowed to identify the relative importance of the main parameters, and to conclude that the distance between carrier beads plays a major role on their interaction with the culture medium and, consequently, on the overall system performance. In an up-scaled version of this bioreactor, the herein presented system may comprise different chambers in serial or parallel configurations. This constitutes a simple way of preparing magnetic responsive beads combined with a new design of bioreactor, which may find application in biomedicine and biotechnology, including in cell expansion for tissue engineering or for the production of therapeutic proteins to be used in cell therapies. (paper)

  15. A half-ring GMR sensor for detection of magnetic beads immobilized on a circular micro-trap

    KAUST Repository

    Gooneratne, Chinthaka Pasan

    2011-11-01

    Utilizing magnetic principles in biological immunoassays is an attractive option given its ability to remotely and non-invasively manipulate and detect cells tagged with micro/nano size superparamagnetic type beads and due to the fact that even the most complex biological immunoassays will have very little magnetic effect. The presence of magnetic beads can be detected by a magnetic sensor which quantifies the amount of target cells present in the immunoassay. In order to increase the detection rate a circular conducting micro-trap is employed to attract, trap and transport the magnetic beads to the sensing area. In this research we propose a half-ring spin valve type giant magnetoresistance (GMR) sensor for the measurement of stray fields produced by 2 μm magnetic beads which are around the circular micro-trap. A couple of half-ring GMR sensors can be used to cover the entire circular border width, in order to detect the majority of the immobilized magnetic beads. Analytical and numerical analysis leading towards the fabrication of the half-ring GMR sensor are presented. DC characterization of the fabricated sensor showed a magnetoresistance of 5.9 %. Experimental results showed that the half-ring GMR sensor detected the presence of 2 μm magnetic beads. Hence, half-ring GMR sensors integrated with a circular micro-trap have great potential to be used as an effective disease diagnostic device. © 2011 IEEE.

  16. The smaller, the better? The size effect of alginate beads carrying plant growth-promoting bacteria for seed coating.

    Science.gov (United States)

    Berninger, Teresa; Mitter, Birgit; Preininger, Claudia

    2016-03-01

    A range of lab-scale methods for encapsulation of plant growth-promoting bacteria in alginate beads intended for seed coating was evaluated: contact-spotting, extrusion through syringe with/without vibration, ejection by robotic liquid handler, extrusion by centrifugal force and commercial devices (nanodispenser, aerodynamically assisted jetting, encapsulator). Two methods were selected based on throughput (encapsulator: 1.5-5 mL/min; syringe with subsequent pulverisation: 5 mL/min). Four bead sizes (55 ± 39 μm, 104 ± 23 μm, 188 ± 16 μm and 336 ± 20 μm after lyophilisation) were produced. Bacterial viability, release, bead morphology, seed surface coverage and attrition were investigated. Release from the smallest bead size was approximately 10 times higher than from the largest. Seed surface coverage was highest (69 ± 3%) when alginate beads produced with nozzle size 80 μm were applied. Pulverised macro-beads are an alternative option, if high throughput is top priority. PMID:26791103

  17. Optimization of Weld Bead Parameters of Nickel Based Overlay Deposited by Plasma Transferred Arc Surfacing with Adequacy Test

    Directory of Open Access Journals (Sweden)

    Bhaskarananda Dasgupta

    2014-07-01

    Full Text Available Plasma Transferred Arc surfacing is a kind of Plasma Transferred Arc Welding process. Plasma Transferred Arc surfacing (PTA is increasingly used in applications where enhancement of wear, corrosion and heat resistance of materials surface is required. The shape of weld bead geometry affected by the PTA Welding process parameters is an indication of the quality of the weld. In this paper the analysis and optimization of weld bead parameters, during deposition of a Nickel based alloy Colmonoy on stainless steel plate by plasma transferred arc surfacing, are made and values of process parameters to produce optimal weld bead geometry are estimated. The experiments are conducted based on a five input process parameters and mathematical models are developed using multiple regression technique. The direct effects of input process parameters on weld bead geometry are discussed using graphs. Finally, optimization of the weld bead parameters, that is minimization of penetration and maximization of reinforcement and weld bead width, are made with a view to economize the input process parameters to achieve the desirable welding joint.

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

    Science.gov (United States)

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

    2014-01-01

    The potential of polysaccharide Irvingia gabonensis matrix as enzyme immobilization support was investigated. Lipase of Aspergillus niger F7-02 was immobilized by entrapment using glutaraldehyde as the cross-linking agent and stabilized in ethanolic-formaldehyde solution. The pH and temperature stability and activity yield of the immobilized enzyme were determined. Such parameters as enzyme load, bead size, number of beads, and bead reusability were also optimized. Adequate gel strength to form stabilized beads was achieved at 15.52% (w/v) Irvingia gabonensis powder, 15% (v/v) partially purified lipase, 2.5% (v/v) glutaraldehyde, and 3 : 1 (v/v) ethanolic-formaldehyde solution. There was 3.93-fold purification when the crude enzyme was partially purified in two-step purification using Imarsil and activated charcoal. Optimum lipase activity 75.3 Ug(-1) was achieved in 50 mL test solution containing 15 beads of 7 mm bead size. Relative activity 80% was retained at eight repeated cycles. The immobilization process gave activity yield of 59.1% with specific activity of 12.3 Umg(-1) and stabilized at optimum pH 4.5 and temperature 55°C. Thus the effectiveness and cost-efficiency of I. gabonensis as a polymer matrix for lipase immobilization have been established. PMID:25614829

  19. 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.

  20. Poly(glycidyl methacrylate) beads embedded cryogels for pseudo-specific affinity depletion of albumin and immunoglobulin G

    International Nuclear Information System (INIS)

    Depletion of high abundant proteins like albumin and immunoglobulin G (IgG) can be beneficial in the analysis of serum proteins. For this purpose, Cibacron Blue F3GA and iminodiacetic acid (IDA)-Cu2+ containing poly(glycidyl methacrylate) (PGMA) beads (1.6 μm in diameter) were embedded into the poly(hydroxyethyl methacrylate) (PHEMA) cryogel. The PGMA beads were prepared by dispersion polymerization. The PGMA beads were modified with Cibacron Blue F3GA and iminodiacetic acid (IDA)-Cu2+ for simultaneous albumin and IgG depletion, respectively. The PHEMA cryogel was synthesized by free radical polymerization in the presence of the modified PGMA beads. The PHEMA and PHEMA/PGMA composite cryogels were characterized by swelling measurements and scanning electron microscopy (SEM). Protein depletion studies were carried out in a continuous experimental set-up in a stacked column. Albumin adsorption capacity of the PGMA-Cibacron Blue F3GA beads embedded PHEMA cryogel (PHEMA/PGMA-Cibacron Blue F3GA) was 342 mg/g and IgG adsorption capacity of the PGMA-IDA-Cu2+ beads embedded PHEMA cryogel (PHEMA/PGMA-IDA-Cu2+) was 257 mg/g. The composite cryogels depleted albumin and IgG from human serum with 89.4% and 93.6% efficiency, respectively. High desorption values (over 90% for both modified cryogels) were achieved with 0.05 M phosphate buffer containing1.0 M NaCl.

  1. Correlation of in-plane bending test and FEA results for thin-walled elbows

    International Nuclear Information System (INIS)

    The objective of this study is to validate a finite element analysis (FEA) simulation methodology to predict the global behavior of thin-walled elbows subjected to in-plane bending. Two in-plane closing mode bending tests and one in-plane opening mode bending test were conducted on 2'' schedule 10 elbows, and a nonlinear FEA procedure was used to simulate the tests. A detailed FEA study was carried out to determine the relative importance of weld size and location, measured wall thicknesses, and original cross-section dimensions on the reconciliation results. When the weld bead was included in the analysis, the reconciliation results for load-displacement behavior and some of the strain measurements were excellent. For those cases in which the strain measurements reconciliations were not so good, a possible explanation is provided

  2. Immobilization of Brassica oleracea Chlorophyllase 1 (BoCLH1 and Candida rugosa Lipase (CRL in Magnetic Alginate Beads: An Enzymatic Evaluation in the Corresponding Proteins

    Directory of Open Access Journals (Sweden)

    Chih-Hui Yang

    2014-08-01

    Full Text Available Enzymes have a wide variety of applications in diverse biotechnological fields, and the immobilization of enzymes plays a key role in academic research or industrialization due to the stabilization and recyclability it confers. In this study, we immobilized the Brassica oleracea chlorophyllase 1 (BoCLH1 or Candida rugosa lipase (CRL in magnetic iron oxide nanoparticles-loaded alginate composite beads. The catalytic activity and specific activity of the BoCLH1 and CRL entrapped in magnetic alginate composite beads were evaluated. Results show that the activity of immobilized BoCLH1 in magnetic alginate composite beads (3.36 ± 0.469 U/g gel was higher than that of immobilized BoCLH1 in alginate beads (2.96 ± 0.264 U/g gel. In addition, the specific activity of BoCLH1 beads (10.90 ± 1.521 U/mg protein was higher than that immobilized BoCLH1 in alginate beads (8.52 ± 0.758 U/mg protein. In contrast, the immobilized CRL in magnetic alginate composite beads exhibited a lower enzyme activity (11.81 ± 0.618 than CRL immobilized in alginate beads (94.83 ± 7.929, and the specific activity of immobilized CRL entrapped in magnetic alginate composite beads (1.99 ± 0.104 was lower than immobilized lipase in alginate beads (15.01 ± 1.255. A study of the degradation of magnetic alginate composite beads immersed in acidic solution (pH 3 shows that the magnetic alginate composite beads remain intact in acidic solution for at least 6 h, indicating the maintenance of the enzyme catalytic effect in low-pH environment. Finally, the enzyme immobilized magnetic alginate composite beads could be collected by an external magnet and reused for at least six cycles.

  3. Walls shielding against ionizing radiation

    International Nuclear Information System (INIS)

    These specifications are to help the users of lead bricks as under DIN 25407, leaf 1, with the construction of walls shielding against ionizing radiation by examples for the uses of the different types of lead bricks and by recommendations for the construction of shielding walls and for the determination of the wall thickness necessary for shielding against γ-radiation as a function of energy. (orig./AK)

  4. Dynamics of monopole walls

    Energy Technology Data Exchange (ETDEWEB)

    Maldonado, R., E-mail: rafael.maldonado@durham.ac.uk; Ward, R.S., E-mail: richard.ward@durham.ac.uk

    2014-06-27

    The moduli space of centred Bogomolny–Prasad–Sommerfield 2-monopole fields is a 4-dimensional manifold M with a natural metric, and the geodesics on M correspond to slow-motion monopole dynamics. The best-known case is that of monopoles on R{sup 3}, where M is the Atiyah–Hitchin space. More recently, the case of monopoles periodic in one direction (monopole chains) was studied a few years ago. Our aim in this note is to investigate M for doubly-periodic fields, which may be visualized as monopole walls. We identify some of the geodesics on M as fixed-point sets of discrete symmetries, and interpret these in terms of monopole scattering and bound orbits, concentrating on novel features that arise as a consequence of the periodicity.

  5. Dynamics of monopole walls

    International Nuclear Information System (INIS)

    The moduli space of centred Bogomolny–Prasad–Sommerfield 2-monopole fields is a 4-dimensional manifold M with a natural metric, and the geodesics on M correspond to slow-motion monopole dynamics. The best-known case is that of monopoles on R3, where M is the Atiyah–Hitchin space. More recently, the case of monopoles periodic in one direction (monopole chains) was studied a few years ago. Our aim in this note is to investigate M for doubly-periodic fields, which may be visualized as monopole walls. We identify some of the geodesics on M as fixed-point sets of discrete symmetries, and interpret these in terms of monopole scattering and bound orbits, concentrating on novel features that arise as a consequence of the periodicity

  6. Dynamics of monopole walls

    CERN Document Server

    Maldonado, R

    2014-01-01

    The moduli space of centred Bogomolny-Prasad-Sommmerfield 2-monopole fields is a 4-dimensional manifold M with a natural metric, and the geodesics on M correspond to slow-motion monopole dynamics. The best-known case is that of monopoles on R^3, where M is the Atiyah-Hitchin space. More recently, the case of monopoles periodic in one direction (monopole chains) was studied a few years ago. Our aim in this note is to investigate M for doubly-periodic fields, which may be visualized as monopole walls. We identify some of the geodesics on M as fixed-point sets of discrete symmetries, and interpret these in terms of monopole scattering and bound orbits, concentrating on novel features that arise as a consequence of the periodicity.

  7. Great Wall of China

    Science.gov (United States)

    2001-01-01

    This ASTER sub-image covers a 12 x 12 km area in northern Shanxi Province, China, and was acquired January 9, 2001. The low sun angle, and light snow cover highlight a section of the Great Wall, visible as a black line running diagonally through the image from lower left to upper right. The Great Wall is over 2000 years old and was built over a period of 1000 years. Stretching 4500 miles from Korea to the Gobi Desert it was first built to protect China from marauders from the north.This image is located at 40.2 degrees north latitude and 112.8 degrees east longitude.Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, Calif., is the U.S. Science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats, monitoring potentially active volcanoes, identifying crop stress, determining cloud morphology and physical properties, wetlands Evaluation, thermal pollution monitoring, coral reef degradation, surface temperature mapping of soils and geology, and measuring surface

  8. Domain wall networks on solitons

    International Nuclear Information System (INIS)

    Domain wall networks on the surface of a soliton are studied in a simple theory. It consists of two complex scalar fields, in 3+1 dimensions, with a global U(1)xZn symmetry, where n>2. Solutions are computed numerically in which one of the fields forms a Q ball and the other field forms a network of domain walls localized on the surface of the Q ball. Examples are presented in which the domain walls lie along the edges of a spherical polyhedron, forming junctions at its vertices. It is explained why only a small restricted class of polyhedra can arise as domain wall networks

  9. Design, fabrication and test of a pneumatically controlled, renewable, microfluidic bead trapping device for sequential injection analysis applications

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Guocheng; Lu, Donglai; Fu, Zhifeng; Du, Dan; Ozanich, Richard M.; Wang, Wanjun; Lin, Yuehe

    2016-01-01

    This paper describes the design, fabrication, and testing of a pneumatically controlled,renewable, microfluidic device for conducting bead-based assays in an automated sequential injection analysis system. The device used a “brick wall”-like pillar array (pillar size: 20 μm length X 50 μm width X 45 μm height) with 5 μm gaps between the pillars serving as the micro filter. The flow channel where bead trapping occurred is 500 μm wide X 75 μm deep. An elastomeric membrane and an air chamber were located underneath the flow channel. By applying pressure to the air chamber, the membrane is deformed and pushed upward against the filter structure. This effectively traps beads larger than 5 μm and creates a “bed” or micro column of beads that can be perfused and washed with liquid samples and reagents. Upon completion of the assay process, the pressure is released and the beads are flushed out from underneath the filter structure to renew the device. Mouse IgG was used as a model analyte to test the feasibility of using the proposed device for immunoassay applications. Resulting microbeads from an on-chip fluorescent immunoassay were individually examined using flow cytometry. The results show that the fluorescence signal intensity distribution is fairly narrow indicating high chemical reaction uniformity among the beads population. Electrochemical onchip assay was also conducted. A detection limit of 0.1 ng/mL1 ppb was achieved and good device reliability and repeatability were demonstrated. The novel microfluidic-based beadstrapping device thus opens up a new pathway to design micro-bead based biosensor immunoassays for clinical and othervarious applications.

  10. Bead-based suspension array for simultaneous differential detection of five major swine viruses.

    Science.gov (United States)

    Chen, Ru; Yu, Xiao-Lu; Gao, Xiao-Bo; Xue, Cun-Yi; Song, Chang-Xu; Li, Yan; Cao, Yong-Chang

    2015-01-01

    A novel multiplex detection array based on Luminex xMAP technology was developed and validated for simultaneous detection of five major viruses causing swine reproductive diseases. By combining one-step asymmetric multiplex reverse transcription polymerase chain reaction (RT-PCR) with xMAP bead-based hybridization and flow cytometry analysis, the resulting multiplex assay was capable of detecting single and mixed infections of PRRSV, PCV-2, PRV, CSFV, and PPV in a single reaction. The assay accurately detected and differentiated 23 viral strains used in this study. The low detection limit was determined as 2.2-22 copies/μL (corresponding to 0.5-6.8 fg/μL DNA template) on plasmid constructs containing viral fragments. The intra-assay and inter-assay variances (CV%) were low that ranged from 2.5 to 5.4 % and 4.1 to 7.6 %, respectively. The assay was applied to test field samples and detected single and mixed viral infections. The detection rate was higher than that of uniplex conventional PCR and RT-PCR methods. The detection of PRRSV by the bead-based multiplex assay was comparable with a commercially available real time RT-PCR kit. The test procedure on purified DNA or RNA samples could be completed within 2 h. In conclusion, the bead-based suspension array presented here proved to be a high-throughput practical tool that provided highly specific and sensitive identification of single and multiple infections of five major viruses in pigs and boar semen. PMID:25557628

  11. Development of a bead-based multiplex genotyping method for diagnostic characterization of HPV infection.

    Directory of Open Access Journals (Sweden)

    Mee Young Chung

    Full Text Available The accurate genotyping of human papillomavirus (HPV is clinically important because the oncogenic potential of HPV is dependent on specific genotypes. Here, we described the development of a bead-based multiplex HPV genotyping (MPG method which is able to detect 20 types of HPV (15 high-risk HPV types 16, 18, 31, 33, 35, 39, 45, 51, 52, 53, 56, 58, 59, 66, 68 and 5 low-risk HPV types 6, 11, 40, 55, 70 and evaluated its accuracy with sequencing. A total of 890 clinical samples were studied. Among these samples, 484 were HPV positive and 406 were HPV negative by consensus primer (PGMY09/11 directed PCR. The genotyping of 484 HPV positive samples was carried out by the bead-based MPG method. The accuracy was 93.5% (95% CI, 91.0-96.0, 80.1% (95% CI, 72.3-87.9 for single and multiple infections, respectively, while a complete type mismatch was observed only in one sample. The MPG method indiscriminately detected dysplasia of several cytological grades including 71.8% (95% CI, 61.5-82.3 of ASCUS (atypical squamous cells of undetermined significance and more specific for high grade lesions. For women with HSIL (high grade squamous intraepithelial lesion and SCC diagnosis, 32 women showed a PPV (positive predictive value of 77.3% (95% CI, 64.8-89.8. Among women >40 years of age, 22 women with histological cervical cancer lesions showed a PPV of 88% (95% CI, 75.3-100. Of the highest risk HPV types including HPV-16, 18 and 31 positive women of the same age groups, 34 women with histological cervical cancer lesions showed a PPV of 77.3% (95% CI, 65.0-89.6. Taken together, the bead-based MPG method could successfully detect high-grade lesions and high-risk HPV types with a high degree of accuracy in clinical samples.

  12. Chemoembolization (TACE) of unresectable intrahepatic cholangiocarcinoma with slow-release doxorubicin-eluting beads: preliminary results.

    Science.gov (United States)

    Aliberti, Camillo; Benea, Giorgio; Tilli, Massimo; Fiorentini, Giammaria

    2008-01-01

    The purpose of this study was to evaluate the safety and efficacy of TACE with microspheres preloaded with doxorubicin in unresectable intrahepatic cholangiocarcinoma (UCH). Twenty patients with UCH were observed; 9 refused, preferring other palliative care or chemotherapy, and 11 agreed to be treated with one or more cycles of DC beads loaded with doxorubicin (100-150 mg) in a TACE procedure between February 2006 and September 2007. A total of 29 individual TACE procedures were performed. Follow-up imaging was performed on all patients before, immediately after, and 4 weeks after each TACE procedure to evaluate the response and need for further treatment. Each patient received i.v hydration, antibiotics, and medications against nausea and pain before TACE. Survival rate was calculated using Kaplan-Meier survival curve. A response rate of 100% followed RECIST criteria was observed. Eight of eleven patients are alive, with a median survival of 13 months. TACE was well tolerated by all patients. One patient developed hepatic abscess requiring antibiotic therapy. No evidence of marrow toxicity has been reported. Only one of nine patients treated with chemotherapy or palliative care is alive (with a median survival of 7 months in this group of patients). In conclusion, we suggest that doxorubicin-eluting beads TACE is a feasible and effective treatment in patients with UCH. Survival seems to be clearly prolonged in the treated group with respect to the palliative group. We consider that doxorubicin-eluting beads TACE of 100-150 mg may be an appropriate palliative therapy for these patients. Further studies are warranted to confirm these interesting preliminary data. PMID:18478290

  13. Chemoembolization (TACE) of Unresectable Intrahepatic Cholangiocarcinoma with Slow-Release Doxorubicin-Eluting Beads: Preliminary Results

    International Nuclear Information System (INIS)

    The purpose of this study was to evaluate the safety and efficacy of TACE with microspheres preloaded with doxorubicin in unresectable intrahepatic cholangiocarcinoma (UCH). Twenty patients with UCH were observed; 9 refused, preferring other palliative care or chemotherapy, and 11 agreed to be treated with one or more cycles of DC beads loaded with doxorubicin (100-150 mg) in a TACE procedure between February 2006 and September 2007. A total of 29 individual TACE procedures were performed. Follow-up imaging was performed on all patients before, immediately after, and 4 weeks after each TACE procedure to evaluate the response and need for further treatment. Each patient received i.v hydration, antibiotics, and medications against nausea and pain before TACE. Survival rate was calculated using Kaplan-Meier survival curve. A response rate of 100% followed RECIST criteria was observed. Eight of eleven patients are alive, with a median survival of 13 months. TACE was well tolerated by all patients. One patient developed hepatic abscess requiring antibiotic therapy. No evidence of marrow toxicity has been reported. Only one of nine patients treated with chemotherapy or palliative care is alive (with a median survival of 7 months in this group of patients). In conclusion, we suggest that doxorubicin-eluting beads TACE is a feasible and effective treatment in patients with UCH. Survival seems to be clearly prolonged in the treated group with respect to the palliative group. We consider that doxorubicin-eluting beads TACE of 100-150 mg may be an appropriate palliative therapy for these patients. Further studies are warranted to confirm these interesting preliminary data.

  14. Biodegradation of 2,4-Dinitrophenol with Laccase Immobilized on Nano-Porous Silica Beads

    Directory of Open Access Journals (Sweden)

    Emad Dehghanifard

    2013-04-01

    Full Text Available Many organic hazardous pollutants, including 2,4-dinitrophenol (2,4-DNP, which are water soluble, toxic, and not easily biodegradable make concerns for environmental pollution worldwide. In the present study, degradation of nitrophenols-contained effluents by using laccase immobilized on the nano-porous silica beads was evaluated. 2,4-DNP was selected as the main constituent of industrial effluents containing nitrophenols. The performance of the system was characterized as a function of pH, contact time, temperature, pollutant, and mediator concentrations. The laccase-silica beads were employed in a mixed-batch reactor to determine the degradation efficiency after 12 h of enzyme treatment. The obtained data showed that the immobilized laccase degraded more than 90% of 2,4-DNP within 12 h treatment. The immobilization process improved the activity and sustainability of laccase for degradation of the pollutant. Temperatures more than 50°C reduced the enzyme activity to about 60%. However, pH and the mediator concentration could not affect the enzyme activity. The degradation kinetic was in accordance with a Michaelis–Menten equation with Vmax and Km obtained as 0.25–0.38 μmoles/min and 0.13–0.017 mM, respectively. The stability of the immobilized enzyme was maintained for more than 85% of its initial activity after 30 days. Based on the results, it can be concluded that high resistibility and reusability of immobilized laccase on CPC-silica beads make it considerable choice for wastewater treatment.

  15. On-bead fluorescent DNA nanoprobes to analyze base excision repair activities

    International Nuclear Information System (INIS)

    Graphical abstract: -- Highlights: •On magnetic beads fluorescent enzymatic assays. •Simple, easy, non-radioactive and electrophoresis-free functional assay. •Lesion-containing hairpin DNA probes are selective for repair enzymes. •The biosensing platform allows the measurement of DNA repair activities from purified enzymes or within cell free extracts. -- Abstract: DNA integrity is constantly threatened by endogenous and exogenous agents that can modify its physical and chemical structure. Changes in DNA sequence can cause mutations sparked by some genetic diseases or cancers. Organisms have developed efficient defense mechanisms able to specifically repair each kind of lesion (alkylation, oxidation, single or double strand break, mismatch, etc). Here we report the adjustment of an original assay to detect enzymes’ activity of base excision repair (BER), that supports a set of lesions including abasic sites, alkylation, oxidation or deamination products of bases. The biosensor is characterized by a set of fluorescent hairpin-shaped nucleic acid probes supported on magnetic beads, each containing a selective lesion targeting a specific BER enzyme. We have studied the DNA glycosylase alkyl-adenine glycosylase (AAG) and the human AP-endonuclease (APE1) by incorporating within the DNA probe a hypoxanthine lesion or an abasic site analog (tetrahydrofuran), respectively. Enzymatic repair activity induces the formation of a nick in the damaged strand, leading to probe's break, that is detected in the supernatant by fluorescence. The functional assay allows the measurement of DNA repair activities from purified enzymes or in cell-free extracts in a fast, specific, quantitative and sensitive way, using only 1 pmol of probe for a test. We recorded a detection limit of 1 μg mL−1 and 50 μg mL−1 of HeLa nuclear extracts for APE1 and AAG enzymes, respectively. Finally, the on-bead assay should be useful to screen inhibitors of DNA repair activities

  16. 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

    bias current through the sensor. The analysis of the single bead response shows that beads always contribute positively to the average magnetic field as opposed to the case for an applied homogeneous magnetic field where the sign of the signal depends on the bead position. General expressions and......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......-field experimentally can be separated from that due to static magnetic fields....

  17. A magnetic bead-based method for concentrating DNA from human urine for downstream detection.

    Directory of Open Access Journals (Sweden)

    Hali Bordelon

    Full Text Available Due to the presence of PCR inhibitors, PCR cannot be used directly on most clinical samples, including human urine, without pre-treatment. A magnetic bead-based strategy is one potential method to collect biomarkers from urine samples and separate the biomarkers from PCR inhibitors. In this report, a 1 mL urine sample was mixed within the bulb of a transfer pipette containing lyophilized nucleic acid-silica adsorption buffer and silica-coated magnetic beads. After mixing, the sample was transferred from the pipette bulb to a small diameter tube, and captured biomarkers were concentrated using magnetic entrainment of beads through pre-arrayed wash solutions separated by small air gaps. Feasibility was tested using synthetic segments of the 140 bp tuberculosis IS6110 DNA sequence spiked into pooled human urine samples. DNA recovery was evaluated by qPCR. Despite the presence of spiked DNA, no DNA was detectable in unextracted urine samples, presumably due to the presence of PCR inhibitors. However, following extraction with the magnetic bead-based method, we found that ∼50% of spiked TB DNA was recovered from human urine containing roughly 5×10(3 to 5×10(8 copies of IS6110 DNA. In addition, the DNA was concentrated approximately ten-fold into water. The final concentration of DNA in the eluate was 5×10(6, 14×10(6, and 8×10(6 copies/µL for 1, 3, and 5 mL urine samples, respectively. Lyophilized and freshly prepared reagents within the transfer pipette produced similar results, suggesting that long-term storage without refrigeration is possible. DNA recovery increased with the length of the spiked DNA segments from 10±0.9% for a 75 bp DNA sequence to 42±4% for a 100 bp segment and 58±9% for a 140 bp segment. The estimated LOD was 77 copies of DNA/µL of urine. The strategy presented here provides a simple means to achieve high nucleic acid recovery from easily obtained urine samples, which does not contain inhibitors of PCR.

  18. Influence of backward flowing molten jet on humping bead formation during high-speed GMA welding

    Institute of Scientific and Technical Information of China (English)

    CHEN Ji; WU Chuansong

    2009-01-01

    Considering the inflttence of backward flowing molten jet observed by experiments, a new pool surface deformation formula and droplets heat content model are used to investigate the humping formation mechanism during high-speed gas metal arc (GMA) welding. Three-dimensional geometry of the humping bead is numerically simulated only if some extra force and heat acted at the rear part of weld pool are taken into account in the model. It has proved that both the momentum and heat content of backward flowing molten jet must be appropriately treated to quantitatively analyze the physical mechanism of the humping phenomenon.

  19. Research on Properties of Foamed Concrete Reinforced with Small Sized Glazed Hollow Beads

    OpenAIRE

    Hu, Chi; Li, Hui; Liu, Zhongwei; Wang, Qingyuan

    2016-01-01

    Foamed concrete (400 kg/m3) was prepared through a physical foaming method using ordinary Portland cement (42.5R), vegetable protein foaming agent, fly ash, and glazed hollow beads (GHB, K46) as raw materials. The performance of cement paste as well as the structure and distribution of air voids was characterized by rheometry, SEM, and XRD analyses with imaging software. The effects of GHBs on the compressive strength and thermal conductivity of the foamed concrete sample were also explored. ...

  20. Ferrous Sulphate Oxidation Using Acidithiobacillus Ferrooxidans Cells Immobilized in Ceramic Beads

    OpenAIRE

    Junfeng, Y.; Guoliang, L.; Wei, C.

    2007-01-01

    The immobilization of Acidithiobacillus ferrooxidans cells on ceramic beads as carrier is described. The effects of ferrous ion concentration and dilution on the kinetics of ferrous ion oxidation in a packed-bed bioreactor were studied. In a medium containing 13.91 g of ferrous ion per litre, the fastest oxidation rate was 4.21 g L–1 at a dilution rate of 0.8 h–1. The corresponding conversion was X = 70 %. At ferrous ion mass concentrations greater than = 8.34 g L–1 and dilution rates greate...