WorldWideScience

Sample records for chain latex particles

  1. Conformational Study of Polypeptide Chains Grafted on the Surface of Polylactide Latex Particle

    OpenAIRE

    Satoshi Tanimoto; Toshiya Iwata; Hitoshi Yamaoka; Masahiro Yamada; Kana Kobori

    2009-01-01

    Polylactide (PLA) latex particle covered with polypeptide chains were prepared by means of solvent exchange method from PLA and PLA-block-polypeptide block copolymer solutions. PLA segment of the block copolymer and PLA homopolymer formed a core of the particle, and the polypeptide segment of the block copolymer, which is designed as tightly fixed biodegradable emulsifier, formed corona around the particle surface. This picture was supported by the fact that zeta-potential of PLA latex partic...

  2. Conformational Study of Polypeptide Chains Grafted on the Surface of Polylactide Latex Particle

    Directory of Open Access Journals (Sweden)

    Satoshi Tanimoto

    2009-01-01

    Full Text Available Polylactide (PLA latex particle covered with polypeptide chains were prepared by means of solvent exchange method from PLA and PLA-block-polypeptide block copolymer solutions. PLA segment of the block copolymer and PLA homopolymer formed a core of the particle, and the polypeptide segment of the block copolymer, which is designed as tightly fixed biodegradable emulsifier, formed corona around the particle surface. This picture was supported by the fact that zeta-potential of PLA latex particle covered with polypeptide segment was different from that of bare PLA particle because of the presence of the ionizable group in the polypeptide chains. To clarify the effect of the ionizable group on conformation of the polypeptide chain, the relation between the polypeptide chain length and the area occupied by the single block chain was evaluated. The result that the occupied area per a polypeptide chain was linearly increased with the increase in the polypeptide chain length indicates that the polypeptide chains trail on the particle surface and did not take helical structures.

  3. Self-assembly of latex particles for colloidal crystals

    Institute of Scientific and Technical Information of China (English)

    Zhirong Li; Jingxia wang; Yanlin Song

    2011-01-01

    Self-assembly of latex particles is of great importance for fabricating various functional colloidal crystals.In this paper,we review recent research on the self-assembly of latex particles for colloidal crystals,covering the assembly forces and various assembly approaches of latex particles,including self-assembly by gravity sedimentation,vertical deposition,physical confinement,electric field,and magnetic field.Furthermore,some simple methods for assembling latex particles such as spin coating,spray coating,and printing are also summarized.

  4. A modulated DSC characterization of morphology of composite latex particles

    International Nuclear Information System (INIS)

    A modulated differential scanning calorimetry (MDSC) method combining transmission electron microscopy (TEM) for characterizing the morphology of composite latex particles has been developed. Sulfonated polystyrene (S-PS)/poly(methyl methacrylate) (PMMA) (50:50 by weight) composite latex particles were prepared as model samples. PS particles were prepared by self-emulsification using lightly S-PS in co-solvents/water. For the preparation of S-PS/PMMA composite latex particles, the guest methyl methacrylate (MMA) monomers first diffused into swollen S-PS particles in S-PS aqueous dispersions, and then the MMA monomers were polymerized. Based on the MDSC method, one can determine quickly whether and what kinds of composite latex particles are prepared. Combing TEM, morphological parameters, such as the radius of core, diffused-phase thickness and thickness of shell of the composite latex particles, can be obtained

  5. A modulated DSC characterization of morphology of composite latex particles

    Energy Technology Data Exchange (ETDEWEB)

    Song, M.; Liao, B

    2004-12-01

    A modulated differential scanning calorimetry (MDSC) method combining transmission electron microscopy (TEM) for characterizing the morphology of composite latex particles has been developed. Sulfonated polystyrene (S-PS)/poly(methyl methacrylate) (PMMA) (50:50 by weight) composite latex particles were prepared as model samples. PS particles were prepared by self-emulsification using lightly S-PS in co-solvents/water. For the preparation of S-PS/PMMA composite latex particles, the guest methyl methacrylate (MMA) monomers first diffused into swollen S-PS particles in S-PS aqueous dispersions, and then the MMA monomers were polymerized. Based on the MDSC method, one can determine quickly whether and what kinds of composite latex particles are prepared. Combing TEM, morphological parameters, such as the radius of core, diffused-phase thickness and thickness of shell of the composite latex particles, can be obtained.

  6. PREPARATION OF HOLLOW LATEX PARTICLES BY ALKALI-ACID TREATMENT

    Institute of Scientific and Technical Information of China (English)

    郝冬梅; 王新灵; 朱卫华; 唐小真; 刘成岑; 施凯

    2001-01-01

    Hollow polymer latex particles were prepared by seeded emulsion polymerization. A seed latex consisting of styrene (St), butyl acrylate(BA) copolymer was first prepared, and seeded terpolymerization of St-BA-MA(methacrylic acid) were then carried out in the absence of surfactant. Final latex was treated by a two-step treatment under alkaline and acidic conditions, thus, the particles with hollow structure were obtained. We discussed the effects of pH value, temperature and time in alkali and acid treatment processes on hollow structure within the polymer latex particles and amount of carboxylic group on particle surface. The results show that the hollow polymer latex particles with the largest hollow size can be obtained under a certain condition (pH12.5, 90°C, 3 h in alkali treatment stage and pH2.5, 85°C, 3 h in acid treatment stage).

  7. Synthesis and engineering of polymeric latex particles for medical applications

    Science.gov (United States)

    Kim, Sangyup

    Latex particles with well-defined colloidal and surface characteristics have received increasing attention due to their useful applications in many areas, especially as solid phase supports in numerous biological applications such as immunoassay, DNA diagnostic, cell separation, and drug delivery carrier. Hemodialysis membrane using these particles would be another potential application for the advanced separation treatment for patients with end stage renal disease (ESRD). It is desirable to remove middle molecular weight proteins with minimal removal of other proteins such as albumin. Thus, it is necessary to understand the fundamental interactions between the particles and blood proteins to maximize the performance of these membranes. This improvement will have significant economic and health impact. The objective of this study is to synthesize polymeric latex particles of specific functionality to achieve the desired selective separation of target proteins from the human blood. Semi-continuous seed emulsion polymerization was used to prepare monodisperse polystyrene seed particles ranging from 126+/-7.5 to 216+/-5.3 nm in size, which are then enlarged by about 800nm. Surfactant amount played a key role in controlling the latex particle size. Negatively charged latex particles with a different hydrophobicity were prepared by introduction of a sodium persulfate initiator and hydrophilic acrylic acid monomer. The prepared polymeric particles include bare polystyrene (PS) particles, less hydrophobic PS core and PMMA shell particles, and more hydrophilic PS core and PMMA-co-PAA shell latex particles with a 370nm mean diameter. SEM, light scattering, and zeta potential measurements were used to characterize particle size and surface properties. Adsorption isotherms of two proteins, bovine serum albumin (BSA) and beta2-microglobulin (beta2M), on latex particles were obtained as a function of pH and ionic strength using the bicinchoninic acid (BCA) assay method. The

  8. Radioactive iodine (125I) labeling of latex particles

    International Nuclear Information System (INIS)

    The invention disclosed in this application is directed towards developing a radioiodination method which is applicable to the labeling of 2.02 micrometer (μm) and 0.37 micrometer (μm) diameter polyvinyltoluene latex particles that have been used as an immunoadsorbent. More particularly the overall method includes using an oxidation-reduction chemical reaction for tagging latex particles. Two methods are described. One, the hydrochloric acid method; and two, the nitric acid method

  9. The Synthesis and Modification of Nanosized Clickable Latex Particles

    KAUST Repository

    Almahdali, Sarah

    2013-05-01

    This research aims to add to the current knowledge available for miniemulsion polymerization reactions and to use this knowledge to synthesize multifunctional nanosized latex particles that have the potential to be used in catalysis. The physical properties of the latex can be adjusted to suit various environments due to the multiple functional groups present. For this research, styrene, pentafluorostyrene, azidomethyl styrene, pentafluorostyrene with azidomethyl styrene and pentafluorostyrene with styrene latexes were produced, and analyzed by dynamic light scattering. The latexes were synthesized using a miniemulsion polymerization technique found through this research. Potassium oleate and potassium 1,1,2,2,3,3,4,4-nonafluorobutane-1-sulfonate were used as surfactants during the miniemulsion polymerization reaction to synthesize pentafluorostyrene with azidomethyl styrene latex. Transmission electron microscopy data and dynamic light scattering data have been collected to analyze the structure of this latex, and it has been synthesized using a number of conditions, differing in reaction time, surfactant amount and sonication methods. We have also improved the solubility of the latex through a copper(I) catalyzed 1,3-dipolar azide-alkyne reaction, by clicking (polyethylene glycol)5000 onto the azide functional groups.

  10. High density monolayers of plasmid protein on latex particles: experiments and theoretical modeling

    Science.gov (United States)

    Kujda, Marta; Adamczyk, Zbigniew; Cieśla, Michał; Adamczyk, Małgorzata

    2015-04-01

    Monolayers obtained by adsorption of the plasmid protein KfrA on negatively charged polystyrene latex particles under diffusion-controlled conditions at pH 3.5 were interpreted in terms of the random sequential adsorption (RSA) model. A quantitative agreement of the theoretical results derived from these calculations with experimental data was attained for the ionic strength from 0.15 up to 10-2 M. This confirmed the adsorption mechanism of KfrA molecules on latex in the form of tetramers up to 10-2 M. On the other hand, for the ionic strength of 10-3 M the experimental coverage agreed with theoretical predictions under the assumption that screening of electrostatic interaction is enhanced by the presence of counterions and negatively charged polymer chains stemming from latex particles.

  11. Production of large-particle-size monodisperse latexes

    Science.gov (United States)

    Vanderhoff, J. W.; El-Aasser, M. L.; Micale, F. J.; Sudol, E. D.; Tseng, C. M.; Silwanowicz, A.

    1984-01-01

    The research program achieved two objectives: (1) it has refined and extended the experimental techniques for preparing monodisperse latexes in quantity on the ground up to a particle diameter of 10 microns; and (2) it has demonstrated that a microgravity environment can be used to grow monodisperse latexes to larger sizes, where the limitations in size have yet to be defined. The experimental development of the monodisperse latex reactor (MLR) and the seeded emulsion polymerizations carried out in the laboratory prototype of the flight hardware, as a function of the operational parameters is discussed. The emphasis is directed towards the measurement, interpretation, and modeling of the kinetics of seeded emulsion polymerization and successive seeded emulsion polymerization. The recipe development of seeded emulsion polymerization as a function of particle size is discussed. The equilibrium swelling of latex particles with monomers was investigated both theoretically and experimentally. Extensive studies are reported on both the type and concentration of initiators, surfactants, and inhibitors, which eventually led to the development of the flight recipes. The experimental results of the flight experiments are discussed, as well as the experimental development of inhibition of seeded emulsion polymerization in terms of time of inhibition and the effect of inhibitors on the kinetics of polymerization.

  12. Comparative study on plant latex particles and latex coagulation in Ficus benjamina, Campanula glomerata and three Euphorbia species.

    Directory of Open Access Journals (Sweden)

    Georg Bauer

    Full Text Available Among latex-producing plants, mainly the latex of Hevea brasiliensis has been studied in detail so far, while comprehensive comparative studies of latex coagulation mechanisms among the more than 20,000 latex-bearing plant species are lacking. In order to give new insights into the potential variety of coagulation mechanisms, the untreated natural latices of five latex-bearing plants from the families Euphorbiaceae, Moraceae and Campanulaceae were visualised using Cryo-SEM and their particle size compared using the laser diffraction method. Additionally, the laticifers of these plants species were examined in planta via Cryo-SEM. Similar latex particle sizes and shape were found in Ficus benjamina and Hevea brasiliensis. Hence, and due to other similarities, we hypothesize comparable, mainly chemical, coagulation mechanisms in these two species, whereas a physical coagulation mechanism is proposed for the latex of Euphorbia spp. The latter mechanism is based on the huge amount of densely packed particles that after evaporation of water build a large surface area, which accelerates the coagulation procedure.

  13. Highly charged hollow latex particles prepared via seeded emulsion polymerization.

    Science.gov (United States)

    Nuasaen, Sukanya; Tangboriboonrat, Pramuan

    2013-04-15

    The carboxylated hollow latex (HL) particles possessing high surface charge density were conveniently prepared by using poly(styrene-co-acrylic acid) (P(St/AA)) as seed particles and methyl methacrylate (MMA)/divinylbenzene (DVB)/AA as monomers. Without seed removal, the hollow structure was simply tuned by adjusting the monomer/seed ratio and the monomer content. The monodisperse, spherical, and non-collapsed HL particles with double shell having the void of 280 nm were obtained from P(St/AA) seeds of 300 nm. The conductimetric back titration, SEM, TEM, and dynamic light scattering measurement revealed that the surface charge density, surface roughness, and size of HL particles significantly increased when applying the stepwise charging monomers/initiator. The highly charged HL particles would be well dispersed in coating film providing good optical properties, for example, opacity and whiteness. PMID:23428072

  14. Xyloglucan-Functional Latex Particles via RAFT-Mediated Emulsion Polymerization for the Biomimetic Modification of Cellulose.

    Science.gov (United States)

    Hatton, Fiona L; Ruda, Marcus; Lansalot, Muriel; D'Agosto, Franck; Malmström, Eva; Carlmark, Anna

    2016-04-11

    Herein, we report a novel class of latex particles composed of a hemicellulose, xyloglucan (XG), and poly(methyl methacrylate) (PMMA), specially designed to enable a biomimetic modification of cellulose. The formation of the latex particles was achieved utilizing reversible addition-fragmentation chain transfer (RAFT) mediated surfactant-free emulsion polymerization employing XG as a hydrophilic macromolecular RAFT agent (macroRAFT). In an initial step, XG was functionalized at the reducing chain end to bear a dithioester. This XG macroRAFT was subsequently utilized in water and chain extended with methyl methacrylate (MMA) as hydrophobic monomer, inspired by a polymerization-induced self-assembly (PISA) process. This yielded latex nanoparticles with a hydrophobic PMMA core stabilized by the hydrophilic XG chains at the corona. The molar mass of PMMA targeted was varied, resulting in a series of stable latex particles with hydrophobic PMMA content between 22 and 68 wt % of the total solids content (5-10%). The XG-PMMA nanoparticles were subsequently adsorbed to a neutral cellulose substrate (filter paper), and the modified surfaces were analyzed by FT-IR and SEM analyses. The adsorption of the latex particles was also investigated by quartz crystal microbalance with dissipation monitoring (QCM-D), where the nanoparticles were adsorbed to negatively charged model cellulose surfaces. The surfaces were analyzed by atomic force microscopy (AFM) and contact angle (CA) measurements. QCM-D experiments showed that more mass was adsorbed to the surfaces with increasing molar mass of the PMMA present. AFM of the surfaces after adsorption showed discrete particles, which were no longer present after annealing (160 °C, 1 h) and the roughness (Rq) of the surfaces had also decreased by at least half. Interestingly, after annealing, the surfaces did not all become more hydrophobic, as monitored by CA measurements, indicating that the surface roughness was an important factor to

  15. Latex allergens in tire dust and airborne particles.

    OpenAIRE

    Miguel, A G; Cass, G R; Weiss, J; Glovsky, M M

    1996-01-01

    The prevalence and severity of latex allergy has increased dramatically in the last 15 years due to exposure to natural rubber products. Although historically this health risk has been elevated in hospital personnel and patients, a recent survey has indicated a significant potential risk for the general population. To obtain a wide-spread source for latex exposure, we have considered tire debris. We have searched for the presence of latex allergens in passenger car and truck tire tread, in de...

  16. The Growth of Latex Particles during the VAc/BA Copolymerization

    Institute of Scientific and Technical Information of China (English)

    QIN Shaoxiong; LIN Jindong; WANG Juan; ZHANG Xinya; CHEN Huanqin

    2006-01-01

    The semi-continuous seeded emulsion copolymerization of vinyl acetate and butyl acrylate was carried out with hydroxyethyl cellulose as a colloid stabilizer. The morphology of the latex particle and the relationship between the reaction time and the average particle diameter and/or the conversion ratio during the polymerization were investigated. The experimental results show that the morphology of the latex particle possesses the stable steric construction. In the seeded polymerization, the average particle diameter of latex decreased while the conversion ratio increased. At the second term of the emulsion copolymerization (the growth stage of particle size), the latex particle average diameter increased with copolymerization continuously, but the instantaneous conversation ratio was not large, so it was very necessary to properly prolong the time during the holding temperature stage.

  17. Direct Observation of the Dynamics of Latex Particles Confined inside Thinning Water-Air Films

    NARCIS (Netherlands)

    Velikov, K.P.; Durst, F.; Velev, O.D.

    2001-01-01

    The dynamics of micrometer-size polystyrene latex particles confined in thinning foam films was investigated by microscopic interferometric observation. The behavior of the entrapped particles depends on the mobility of the film surfaces, the particle concentration, hydrophobicity, and rate of film

  18. Light scattering of PMMA latex particles in benzene: structural effects

    NARCIS (Netherlands)

    Nieuwenhuis, E.A.; Vrij, A.

    1979-01-01

    Intra- and interparticle structural effects were studied in polymethylmethacrylate (PMMA) latex dispersions in a nonpolar solvent with the technique of light scattering. The required transparency of the dispersions was attained by a close matching of the refractive index of PMMA and solvent, for whi

  19. Preparation of sulphonate-containing core/shell latex particles via seeded emulsion copolymerization

    Institute of Scientific and Technical Information of China (English)

    Ji Shuai Wang; Wei Deng; Yun Shen Chen; Cheng You Kan

    2010-01-01

    In this study,P(St-MAA)seed latex particles were first prepared via soap-free emulsion polymerization of styrene(St)and methacrylic acid(MAA),then the seed particles were allowed to swell with St at room temperature,and the P(St-MAA)/P(St-NaSS)core/shell latex particles were then synthesized via seeded emulsion copolymerization of St and sodium styrene sulphonate(NaSS)using AIBN as initiator in the presence of N,N'-methylenebisacrylamide(BAA,water-soluble crosslinker).Results showed that the polymerization could be carried out smoothly when the ratio of BAA to total monomers was less than 3 mol%,the narrow dispersed P(St-MAA)seed particles with the diameter of 150 nm and the P(St-MAA)/P(St-NaSS)core/shell latexes with the particle size of about 200 nm were synthesized.When the 25/75 mole ratio of NaSS/(St+MAA)and 2 mol% of BAA were used in the seeded emulsion polymerization,the resulted P(St-MAA)/P(St-NaSS)latex product showed a low weight loss after water extraction,and the NaSS unit content in the whole particle and in the shell reached 11.7 mol% and 34.6 mol%,respectively.

  20. Latex particle template lift-up guided gold wire-networks via evaporation lithography

    KAUST Repository

    Lone, Saifullah

    2014-01-01

    We describe a hybrid methodology that combines a two dimensional (2D) monolayer of latex particles (with a pitch size down to 1 μm) prepared by horizontal dry deposition, lift-up of a 2D template onto flat surfaces and evaporation lithography to fabricate metal micro- and nano wire-networks. This journal is

  1. The electrokinetic properties of latex particles:comparison of electrophoresis and dielectrophoresis

    OpenAIRE

    Ermolina, Irina; Morgan, Hywel

    2004-01-01

    A comprehensive study of the AC and DC electrokinetic properties of submicrometer latex particules as a function of particle size and suspending medium conductivity and viscosity is present. Electrophoretic mobility and dielectrophoretic cross-over results were measured for particule diameters ranging from 44 to 2000 nm. The zeta potentials of the particles were calculated from gthe electrophoretic mobility data for different suspending medium conductivities, using various models, with and wi...

  2. Biomimetic folding particle chains

    International Nuclear Information System (INIS)

    Full text: The sequence of the amino acids in proteins dictates their folded 3-D structure. We have recently by simulations shown that this principle can be applied to flexible strings of isotropically interacting particles with at least one attractive patchy interaction, allowing the design of new materials and structures. Our goal is now to realize this directed self-folding on a colloidal size scale to study the folding in real time in real space. We discuss our use of polymer brushes, depletion interactions and liquid-interface scaffold chemistry to realize the goal. (author)

  3. Plasma etching of polystyrene latex particles for the preparation of graphene oxide nanowalls

    Directory of Open Access Journals (Sweden)

    Bon Bittolo Silvia

    2012-01-01

    Full Text Available Graphene oxide nanowalls were prepared by casting a water dispersion of polystyrene latex particles onto a graphene oxide film followed by tetrafluoromethane plasma etching. Mild plasma etching conditions allow one to retain the oxygen functional groups on the graphene oxide nanowalls. It was found that the exposure to a xenon light source of such graphene oxide nanowalls coated with a gold thin film results in an increase of the electrical conductivity.

  4. Plasma etching of polystyrene latex particles for the preparation of graphene oxide nanowalls

    OpenAIRE

    Bon Bittolo Silvia; Valentini Luca

    2012-01-01

    Graphene oxide nanowalls were prepared by casting a water dispersion of polystyrene latex particles onto a graphene oxide film followed by tetrafluoromethane plasma etching. Mild plasma etching conditions allow one to retain the oxygen functional groups on the graphene oxide nanowalls. It was found that the exposure to a xenon light source of such graphene oxide nanowalls coated with a gold thin film results in an increase of the electrical conductivity.

  5. MONODISPERSED AND NANOSIZED DENDRIMER/POLYSTYRENE LATEX PARTICLES

    Institute of Scientific and Technical Information of China (English)

    Changfeng Yi; Zushun Xu; Warren T. Ford

    2004-01-01

    Emulsion polymerization of styrene was carried out using dendrimer DAB-dendr-(NH2)64 as seed. The size and size distribution of the emulsion particles were characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS), and the effects of emulsion polymerization conditions on the preparation of emulsion particle were investigated. It has been found that the nanosized dendrimer/polystyrene polymer emulsion particles obtained were in the range of 26~64 nm in diameter, and were monodisperse; the size and size distribution of emulsion particles were influenced by the contents of dendrimer DAB-dendr-(NH2)64, emulsifier and initiator, as well as the pH value.

  6. Deposition behavior of latex particles in filtration process through glass packed column

    International Nuclear Information System (INIS)

    Most studies on radionuclide migration in groundwater have focused on the transport of dissolved forms of radionuclides. Colloidal particles, however, can play an important role in the migration. The colloids act as a third phase which is neither a liquid nor a solid phase. This phase can increase the amount of actinides that can migrate in a natural aquifer system. The deposition behavior of colloids from a flowing suspension onto a solid collector surface in filtration process was observed by conducting column experiments with polystyrene latex particles and glass beads packed columns. From the observed particle breakthrough curves, single collector efficiencies were calculated. By comparing the single collector efficiency obtained in the column experiment with the existing approximate expression, the effects of flow velocity on the deposition behavior was discussed

  7. Particle size, morphology and color tunable ZnO:Eu3+ nanophosphors via plant latex mediated green combustion synthesis

    International Nuclear Information System (INIS)

    Highlights: • ZnO:Eu3+ phosphors were prepared by green synthesis route. • Morphology and particle size was tuned by varying the concentration of plant latex. • The phosphor show excellent chromaticity coordinates in the white region. -- Abstract: Efficient ZnO:Eu3+ (1–11 mol%) nanophosphors were prepared for the first time by green synthesis route using Euphorbia tirucalli plant latex. The final products were well characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–visible spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FTIR), etc. The average particle size of ZnO:Eu3+ (7 mol%) was found to be in the range 27–47 nm. With increase of plant latex, the particle size was reduced and porous structure was converted to spherical shaped particles. Photoluminescence (PL) spectra indicated that the peaks situated at ∼590, 615, 648 and 702 nm were attributed to the 5D0 → 7Fj(j=1,2,3,4) transitions of Eu3+ ions. The highest PL intensity was recorded for 7 mol% with Eu3+ ions and 26 ml plant latex concentration. The PL intensity increases with increase of plant latex concentration up to 30 ml and there after it decreases. The phosphor prepared by this method show spherical shaped particles, excellent chromaticity co-ordinates in the white light region which was highly useful for WLED’s. Further, present method was reliable, environmentally friendly and alternative to economical routes

  8. Single-molecule detection of proteins with antigen-antibody interaction using resistive-pulse sensing of submicron latex particles

    Science.gov (United States)

    Takakura, T.; Yanagi, I.; Goto, Y.; Ishige, Y.; Kohara, Y.

    2016-03-01

    We developed a resistive-pulse sensor with a solid-state pore and measured the latex agglutination of submicron particles induced by antigen-antibody interaction for single-molecule detection of proteins. We fabricated the pore based on numerical simulation to clearly distinguish between monomer and dimer latex particles. By measuring single dimers agglutinated in the single-molecule regime, we detected single human alpha-fetoprotein molecules. Adjusting the initial particle concentration improves the limit of detection (LOD) to 95 fmol/l. We established a theoretical model of the LOD by combining the reaction kinetics and the counting statistics to explain the effect of initial particle concentration on the LOD. The theoretical model shows how to improve the LOD quantitatively. The single-molecule detection studied here indicates the feasibility of implementing a highly sensitive immunoassay by a simple measurement method using resistive-pulse sensing.

  9. Latex particles functionalized with transition metals ferrocyanides for cesium uptake and decontamination of solid bulk materials

    International Nuclear Information System (INIS)

    Decontamination of spent ion-exchange resins, corrosion-unstable metal structures, soil, ground, and construction materials contaminated by fission, corrosion and transuranic radionuclides remains one of the most urgent and complicated ecological problems. Among the existing methods having different efficiencies in regard to such materials decontamination, application of selective sorbents put into a humid medium to be decontaminated (ground, bulk materials) appears to be rather extensive. However, the efficiency of such an approach is significantly limited by difficulties concerned with uniform sorbent distribution in porous media and completeness of spent sorbents removal for final disposal. In this paper we suggest a principally new approach to preparation of colloid-stable selective sorbents for cesium uptake using immobilization of transition metals (cobalt, nickel, and copper) ferrocyanides in nanosized carboxylic latex emulsions. The effects of ferrocyanide composition, pH, and media salinity on the sorption properties of the colloid-stable sorbents toward cesium ions were studied in solutions containing up to 200 g/1 sodium nitrate or potassium chloride. The sorption capacities of the colloid sorbents based on mixed potassium/transition metals ferrocyanides were in the range 1.45-1.86 mol Cs/mol ferrocyanide with the highest value found for the copper ferrocyanide. It was shown that the obtained colloid-stable sorbents were capable to penetrate through bulk materials without filtration that makes them applicable for decontamination of solids, e.g. soils, zeolites, spent ion-exchange resins contaminated with cesium radionuclides. After decontamination of liquid or solid radioactive wastes the colloid-stable sorbents can be easily separated from solutions by precipitation with cationic flocculants providing localization of radionuclides in a small volume of the precipitates formed. Besides, functionalized latex particles can be used for preparation of carbon

  10. Latex Allergy

    Science.gov (United States)

    ... requires immediate medical attention. The thin, stretchy latex rubber in gloves, condoms and balloons is high in this protein. ... Latex is a rubber product. Am I at risk for other rubber allergies? What products contain latex? How do I ...

  11. Flow cytometric quantitation of phagocytosis in heparinized complete blood with latex particles and Candida albicans

    Directory of Open Access Journals (Sweden)

    Jesús M. Egido

    1997-12-01

    Full Text Available We report a rapid method for the flow cytometric quantitation of phagocytosis in heparinized complete peripherial blood (HCPB, using commercially available phycoerythrin-conjugated latex particles of 1µm diameter. The method is faster and shows greater reproducibility than Bjerknes' (1984 standard technique using propidium iodide-stained Candida albicans, conventionally applied to the leukocytic layer of peripherial blood but here modified for HCPB. We also report a modification of Bjerknes' Intracellular Killing Test to allow its application to HCPB.Se da cuenta de un método rápido para la cuantización del flujo citométrico de la fagocitosis en sangre periférica completamente heparinizada (HCPB, mediante la utilización de partículas de látex phycoerythrin-conjugadas de 1µm de diámetro disponibles comercialmente. El método es más rápido y presenta mayor reproducibilidad que la técnica estandar de Bjerknes' (1984 utilizando propidium iodide-teñida Candida albicans, aplicada convencionalmente a la capa leucocitica de sangre periférica pero modificada por HCPB. Tambien damos cuenta de una modificación de Bjerknes' Intracellular Killing Test para permitir su aplicación a HCPB.

  12. Removal of bisphenol A and some heavy metal ions by polydivinylbenzene magnetic latex particles.

    Science.gov (United States)

    Marzougui, Zied; Chaabouni, Amel; Elleuch, Boubaker; Elaissari, Abdelhamid

    2016-08-01

    In this study, magnetic polydivinylbenzene latex particles MPDVB with a core-shell structure were tested for the removal of bisphenol A (BPA), copper Cu(II), lead Pb(II), and zinc Zn(II) from aqueous solutions by a batch-adsorption technique. The effect of different parameters, such as initial concentration of pollutant, contact time, adsorbent dose, and initial pH solution on the adsorption of the different adsorbates considered was investigated. The adsorption of BPA, Cu(II), Pb(II), and Zn(II) was found to be fast, and the equilibrium was achieved within 30 min. The pH 5-5.5 was found to be the most suitable pH for metal removal. The presence of electrolytes and their increasing concentration reduced the metal adsorption capacity of the adsorbent. Whereas, the optimal pH for BPA adsorption was found 7, both hydrogen bonds and π-π interaction were thought responsible for the adsorption of BPA on MPDVB. The adsorption kinetics of BPA, Cu(II), Pb(II), and Zn(II) were found to follow a pseudo-second-order kinetic model. Equilibrium data for BPA, Cu(II), Pb(II), and Zn(II) adsorption were fitted well by the Langmuir isotherm model. Furthermore, the desorption and regeneration studies have proven that MPDVB can be employed repeatedly without impacting its adsorption capacity. PMID:26396007

  13. Charge of dust particles in a particle chain

    CERN Document Server

    Yousefi, Razieh; Matthews, Lorin Swint; Hyde, Truell W

    2016-01-01

    Charged dust particles form structures which are extended in the vertical direction in the electrode sheath of a rf discharge when confined within a glass box. The charge on each particle as a function of height varies due to the changing plasma conditions and the wakefield of upstream particles. Here an analysis of the equilibrium state of chains of varying number of particles is analyzed to determine the charge on each particle within a vertically extended chain as well as the magnitude of the positive wakefield charge.

  14. Nucleation of polystyrene latex particles in the presence of gamma-methacryloxypropyltrimethoxysilane: functionalized silica particles.

    Science.gov (United States)

    Bourgeat-Lami, Elodie; Insulaire, Mickaelle; Reculusa, Stéphane; Perro, Adeline; Ravaine, Serge; Duguet, Etienne

    2006-02-01

    Silica/polystyrene nanocomposite particles with different morphologies were synthesized through emulsion polymerization of styrene in the presence of silica particles previously modified by gamma-methacryloxypropyltrimethoxysilane (MPS). Grafting of the silane molecule was performed by direct addition of MPS to the aqueous silica suspension in the presence of an anionic surfactant under basic conditions. The MPS grafting density on the silica surface was determined using the depletion method and plotted against the initial MPS concentration. The influence of the MPS grafting density, the silica particles size and concentration and the nature of the surfactant on the polymerization kinetics and the particles morphology was investigated. When the polymerization was performed in the presence of an anionic surfactant, transmission electron microscopy images showed the formation of polymer spheres around silica for MPS grafting densities lower than typically 1 micromole x m(-2) while the conversion versus time curves indicated a strong acceleration effect under such conditions. In contrast, polymerizations performed in the presence of a larger amount of MPS moieties or in the presence of a non ionic emulsifier resulted in the formation of "excentered" core-shell morphologies and lower polymerization rates. The paper identifies the parameters that allow to control particles morphology and polymerization kinetics and describes the mechanism of formation of the nanocomposite colloids. PMID:16573042

  15. STUDIES ON POLYSILOXANE-POLYSTYRENE COMPOSITE LATEXES

    Institute of Scientific and Technical Information of China (English)

    HUANG Ying; LIU Xianglian; YU Yunzhao

    1994-01-01

    Polysiloxane-polystyrene composite latexes were prepared by two-stage emulsion polymerization. Polymerization of styrene in swollen polysiloxane latex particles were studied.Formation of simple polystyrene particle in the 2nd-stage polymerization depends on the particle size of the 1st-stage latex and the polymerization temperature. Polystyrene domains in the vulcanizates reinforce the silicone rubbers effectively.

  16. Interacting Particle Markov Chain Monte Carlo

    OpenAIRE

    Rainforth, Tom; Naesseth, Christian A.; Lindsten, Fredrik; Paige, Brooks; van de Meent, Jan-Willem; Doucet, Arnaud; Wood, Frank

    2016-01-01

    We introduce interacting particle Markov chain Monte Carlo (iPMCMC), a PMCMC method that introduces a coupling between multiple standard and conditional sequential Monte Carlo samplers. Like related methods, iPMCMC is a Markov chain Monte Carlo sampler on an extended space. We present empirical results that show significant improvements in mixing rates relative to both non-interacting PMCMC samplers and a single PMCMC sampler with an equivalent total computational budget. An additional advant...

  17. Separation and characterization of poly(tetrafluoroethylene) latex particles by asymmetric flow field flow fractionation with light-scattering detection.

    Science.gov (United States)

    Collins, Melissa E; Soto-Cantu, Erick; Cueto, Rafael; Russo, Paul S

    2014-04-01

    Poly(tetrafluoroethylene) (PTFE) latex particles have been analyzed and sorted according to size using asymmetric flow field flow fractionation (AF4) coupled with multiple-angle light scattering (MALS). Characterization of fractions by regular and depolarized dynamic light scattering confirmed that smaller particles elute prior to larger ones, as expected for field flow fractionation. The measured radii of the optically and geometrically anisotropic particles are consistent with those determined from transmission electron microscopy (TEM). A certain amount of heterogeneity remains in the fractions, but their uniformity for use as diffusion probes is improved. Full characterization of PTFE colloids will require a difficult assessment of the distribution, even within fractions, of the optical anisotropy. A general method to obtain number versus size distributions is presented. This approach is valid even when an online concentration detector is not available or ineffective. The procedure is adaptable to particles of almost any regular shape. PMID:24635125

  18. Use of hydrophobically modified inulin for the preparation of polymethyl methacrylate/polybutyl acrylate latex particles using a semicontinuous reactor.

    Science.gov (United States)

    Obiols-Rabasa, M; Ramos, J; Forcada, J; Esquena, J; Solans, C; Levecke, B; Booten, K; Tadros, Tharwat F

    2010-06-01

    The seeded semicontinuous emulsion copolymerization of methyl methacrylate (MMA) and butyl acrylate (BuA) stabilized with a graft polymeric surfactant based on inulin, INUTEC SP1, as well as its mixture with sodium lauryl sulfate (SLS) is described. The mixture of SLS and Brij58 (alcohol ethoxylated) and the mixture of SLS and Pluronic P85 (block copolymer PEO-PPO-PEO) are also used as surfactant systems. The addition of methacrylic acid (MAA) or acrylic acid (AA) as comonomers is also studied. Previous results proved this inulin-derivative surfactant, INUTEC SP1, to be very effective on synthesizing latexes using a very low surfactant concentration. The kinetic features of the emulsion polymerization (instantaneous conversion and total conversion) were gravimetrically determined along the reactions. Latex dispersions were characterized by photon correlation spectroscopy (PCS) and transmission electron microscopy (TEM) to obtain the average particle size, the particle size distributions (PSDs) as well as the polydispersity index (PdI). The stability was determined by turbidimetry measurements and expressed in terms of critical coagulation concentration. The results showed that the use of the graft polymeric surfactant allowed obtaining highly stable nanoparticles, at low surfactant concentrations and high solid contents (up to 37 wt %). This is an improvement with respect to previous works, in which a mixture of the graft polymeric surfactant with another surfactant was required to obtain stable nanoparticles with low polydispersity, at high solid content. In the present work, low polydispersity was achieved using INUTEC as the only emulsifier, which was related to the absence of secondary nucleations. When a mixture of INUTEC SP1 and SLS is used, a wider PSD is obtained due to secondary nucleations. Replacing INUTEC SP1 by other nonionic surfactants such as Brij58 or Pluronic P85 leads to an increase of average particle size and wider PSD. PMID:20121169

  19. Practical Latex

    CERN Document Server

    Grätzer, George

    2014-01-01

    Accessible at 200+ pages to all who want to learn the practical usages of LaTeX Avoids technical subjects like font usage Friendly and easy to read, with many examples included Extra source materials include sample LaTeX files and suggestions for further reading

  20. Effect of styrene and methyl methacrylate comonomers in ethyl acrylate/methacrylic acid latex on particle alkali-swellability, film formation and thickening with associative thickeners

    Czech Academy of Sciences Publication Activity Database

    Šňupárek, J.; Quadrat, Otakar; Horský, Jiří

    2005-01-01

    Roč. 54, č. 2 (2005), s. 99-103. ISSN 0300-9440 R&D Projects: GA ČR(CZ) GA104/02/1360 Institutional research plan: CEZ:AV0Z40500505 Keywords : acrylic latices * alkali-swellable latex particles * hydroplasticization Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.535, year: 2005

  1. [Latex allergy].

    Science.gov (United States)

    Richter, J; Susický, P

    2000-04-01

    The authors describe a case of an allergic affection in a patient with occupational exposure to latex allergens with a history of anaphylactic reaction to poppy seed and reaction to the antigens of apples, oranges, tangerines, peanuts and bananas, revealed by the method CAP Phadiatop. A marked reaction was initiated after the use of a shampoo containing volatile banana oil. The authors emphasize the high incidence of latex allergy, the manifestations of which may be encountered also in clinical ophthalmology. PMID:10874793

  2. Testicular biodistribution of 450 nm fluorescent latex particles after intramuscular injection in mice.

    OpenAIRE

    Klein, Jean-Philippe; Boudard, Delphine; Cadusseau, Josette; Palle, Sabine; Forest, Valérie; Pourchez, Jérémie; Cottier, Michèle

    2013-01-01

    The significant expansion in the use of nanoparticles and submicron particles during the last 20 years has led to increasing concern about their potential toxicity to humans and particularly their impact on male fertility. Currently, an insufficient number of studies have focused on the testicular biodistribution of particles. The aim of our study was to assess the distribution of 450 nm fluorescent particles in mouse testes after intramuscular injection. To this end, testes were removed from...

  3. Experimental determination of particle size distributions in colloidal systems by dynamic light scattering. Application to polystyrene latex spheres and to nonionic microemulsions

    OpenAIRE

    Eshuis, A; Harbers, G.; Doornink, D.J.; Mijnlieff, P.F.

    1985-01-01

    Information about polydisperse colloidal systems was obtained by dynamic light scattering. The correlation functions obtained were analyzed by the histogram method and the method of cumulants. The former was, as a test, applied to a nearly monodispere polystyrene latex. The agreement between the obtained results and the values given by the supplier was rather good. Therefore, this technique was applied to some nonionic microemulsions to determine their particle size distribution. The results ...

  4. STIMULATION OF OXIDANT PRODUCTION IN ALVEOLAR MACROPHAGES BY POLLUTANT AND LATEX PARTICLES

    Science.gov (United States)

    Air pollutant dusts as well as chemically defined particles were examined for their activating effect on oxidant production (O2- and H2O2) in guinea pig alveolar macrophages (AM). Oxidant production was measured as chemiluminescence of albumin-bound luminol. All particles examine...

  5. Deposition behavior of polystyrene latex particles on solid surfaces during migration through an artificial fracture in a granite rock sample

    International Nuclear Information System (INIS)

    The deposition behavior of colloids during transport through heterogeneous media was observed by conducting column experiments to study migration of polystyrene latex particles (diameter=309 nm) through columns packed with artificially fractured granite rock (length=300 and 150 mm). The experiments were conducted under conditions of different ionic strengths and flow rates. The results were similar to those for colloid deposition in columns packed with glass beads reported previously; the colloid breakthrough curves showed three stages, characterized by different rates of change in the concentration of effluent. Colloid deposition on the fracture surfaces was described by considering strong and weak deposition sites. Scanning Electron Microscopy (SEM) observations indicated the existence of strong and weak sites on the fracture surfaces regardless of mineral composition. The observations also showed that the strong deposition sites tended to exist on surface irregularities such as cracks or protrusions. The degree of colloid deposition increased with increasing ionic strength and decreasing flow rate. The dependencies on ionic strength and flow rate agreed qualitatively with the DLVO theory and the previous experimental results, respectively. (author)

  6. Emission spectrum of the atomic chain excited by channeled particle

    CERN Document Server

    Epp, V

    2014-01-01

    Basic properties of radiation of the atomic chains excited by a channeled particle are considered. Using a very simple two-dimensional model of a crystal lattice we have shown that the main part of this radiation is generated on the frequency of oscillations of a channeled particle between the crystal planes, shifted by the Doppler effect. Spectral and angular distribution and spectral distribution of the radiation of the atomic chain excited by channeled particle were calculated. Emission spectrum of the atomic chain excited by channeled particle was plotted.

  7. Film formation from latex blends

    Science.gov (United States)

    Tang, Jiansheng

    2000-10-01

    Film formation from hard/soft (i.e., high Tg/low Tg) latex blends consisting of hard polystyrene (PS) and soft poly(n-butyl methacrylate-co-n-butyl acrylate) [P(BMA/BA)] latex particles were studied with an emphasis on the influence of the carboxyl groups present on the latex particles. A theoretical model was developed to calculate the optimal surfactant and monomer feed rates for a semicontinuous polymerization process to synthesize monodisperse carboxylated latex particles and independently control the particle size and degree of carboxylation. An important finding obtained from the drying studies is that the drying rate from the edge zone is much faster than the rate obtained from the latex pool. It was also found that the presence of carboxyl groups on the latex particles retarded the drying rate. Utilizing PS particles with a low density of carboxyl groups present on the particle surfaces (e.g., 10% surface coverage) resulted in an even distribution of these particles in the soft copolymer matrix, and thus, good film gloss was achieved. However, the use of hard particles with a high density of carboxyl groups present (e.g., 65% coverage) resulted in a less even distribution of PS particles and poor gloss. A cluster model and a hydrogen bonding mechanism were proposed to explain these phenomena. The presence of the carboxyl groups on the PS particles significantly enhanced the Young's modulus and the yield strength, but did not influence the ultimate mechanical properties. A quantitative model was proposed to predict the Young's modus of the latex blend films as a function of the carboxyl group coverage on the hard particles. There was a good fit between model and the experimental data. The stability of the precipitated calcium carbonate (PCC) particles in the P(BMA/BA) latexes was determined by the charge on pigment surface which, in turn, was influenced by the presence of sodium polyacrylate stabilizer. It was found that the wetting ability of the soft

  8. Thermodynamic Equilibrium Morphology Prediction of Polyurethane/Polyacrylate Composite Latex Particles

    Institute of Scientific and Technical Information of China (English)

    CHAI Shu-Ling; JIN Ming-Martin

    2008-01-01

    Composite particles were prepared by seeded surfactant-free batch emulsion polymerization at 80 ℃ using K2S2O8 as an initiator, and polyurethane aqueous dispersion as seed particles. The acrylate monomers were continuously added into the reactor under a starving condition in the second stage polymerization. The synthesized hybrid emulsions were found to form an inverted core-shell structure with polyacrylate as the core and with polyurethane as the shell from the observation with a transmission electron microscope. The interfacial tensions between polymer and polymer as well as polymer and water were calculated with a simple method according to harmonic mean equation and used in a mathematical model based on the minimum interfacial energy change principle to predict the equilibrium morphology. The observed particle morphologies were in good agreement with the predicted ones. The surface properties of the dried films formed from polyurethane (PU)/polyacrylate (PA) composite emulsions were also studied by contact angle measurements, showing that the shell part of the composite emulsions is preferentially oriented toward the surface layers of the dried films.

  9. On the particle excitations in the XXZ- spin chain

    CERN Document Server

    Ovchinnikov, A A

    2013-01-01

    We continue to study the excited states for the XXZ- spin chain corresponding to the complex roots of the Bethe Ansatz equations with the imaginary part equal to $\\pi/2$. We propose the particle-hole symmetry which relates the eigenstates build up from the two different pseudovacuum states. We find the XXX- spin chain limit for the eigenstates with the complex roots. We also comment on the low-energy excited states for the XXZ- spin chain.

  10. Bacterial turbulence reduction by passive magnetic particle chains

    Science.gov (United States)

    Liu, Kuo-An; I, Lin

    2013-09-01

    We report the experimental observation of the bacterial turbulence reduction in dense E. coli suspensions by increasing the coupling of passive particle additives (paramagnetic particles). Applying an external magnetic field induces magnetic dipoles for particles and causes the formation of vertical chain bundles, which are hard for bacterial flows to tilt and break. The larger effective drag coefficient of chains causes slow horizontal motion of chains, which in turn form obstacles to suppress bacterial flows through the strong correlation in coherent bacterial clusters and intercluster interaction. The interruption of the upward energy flow from individual self-propelling bacteria to the larger scale in the bacterial turbulence with multiscaled coherent flow by the chain bundle leads to more severe suppression in the low frequency (wave number) regimes of the power spectra.

  11. Dynamics of Single Chains of Suspended Ferrofluid Particles

    Science.gov (United States)

    Cutillas, S.; Liu, J.

    1999-01-01

    We present an experimental study of the dynamics of isolated chains made of super-paramagnetic particles under the influence of a magnetic field. The motivation of this work is to understand if the chain fluctuations exist and, if it does, how does the fluctuation affect chain aggregation. We find that single chains strongly fluctuate and that the characteristic frequency of their fluctuations is inversely proportional to the magnetic field strength. The higher the field the lower the characteristic frequency of the chain fluctuations. In the high magnetic field limit, chains behave like rigid rods without any internal motions. In this work, we used ferrofluid particles suspended in water. These particles do not have any intrinsic magnetization. Once a magnetic field is applied, a dipole moment is induced in each particle, proportional to the magnetic field. A dipolar magnetic interaction then occurs between particles. If dipole-dipole magnetic energy is higher than the thermal energy, the result is a structure change inside the dipolar fluid. The ratio of these two energies is expressed by a coupling constant lambda as: lambda = (pi(a(exp 3))(chi(exp 2))(mu(sub 0))(H(sub 0))(exp 2))/18kT Where a is the particle radius, mu(sub 0) is the vacuum magnetic permeability, H(sub 0) the applied magnetic field, k the Boltzmann constant and T the absolute temperature. If lambda > 1, magnetic particles form chains along the field direction. The lateral coalescence of several chains may form bigger aggregates especially if the particle volume fraction is high. While many studies and applications deal with the rheological properties and the structural changes of these dipolar fluids, this work focuses on the understanding of the chain dynamics. In order to probe the chain dynamics, we used dynamic light scattering (DLS) in self-beating mode as our experimental technique. The experimental geometry is such that the scattering plane is perpendicular to the magnetic field

  12. Characterization of rubber particles and rubber chain elongation in Taraxacum koksaghyz

    Directory of Open Access Journals (Sweden)

    Prüfer Dirk

    2010-02-01

    Full Text Available Abstract Background Natural rubber is a biopolymer with exceptional qualities that cannot be completely replaced using synthetic alternatives. Although several key enzymes in the rubber biosynthetic pathway have been isolated, mainly from plants such as Hevea brasiliensis, Ficus spec. and the desert shrub Parthenium argentatum, there have been no in planta functional studies, e.g. by RNA interference, due to the absence of efficient and reproducible protocols for genetic engineering. In contrast, the Russian dandelion Taraxacum koksaghyz, which has long been considered as a potential alternative source of low-cost natural rubber, has a rapid life cycle and can be genetically transformed using a simple and reliable procedure. However, there is very little molecular data available for either the rubber polymer itself or its biosynthesis in T. koksaghyz. Results We established a method for the purification of rubber particles - the active sites of rubber biosynthesis - from T. koksaghyz latex. Photon correlation spectroscopy and transmission electron microscopy revealed an average particle size of 320 nm, and 13C nuclear magnetic resonance (NMR spectroscopy confirmed that isolated rubber particles contain poly(cis-1,4-isoprene with a purity >95%. Size exclusion chromatography indicated that the weight average molecular mass (w of T. koksaghyz natural rubber is 4,000-5,000 kDa. Rubber particles showed rubber transferase activity of 0.2 pmol min-1 mg-1. Ex vivo rubber biosynthesis experiments resulted in a skewed unimodal distribution of [1-14C]isopentenyl pyrophosphate (IPP incorporation at a w of 2,500 kDa. Characterization of recently isolated cis-prenyltransferases (CPTs from T. koksaghyz revealed that these enzymes are associated with rubber particles and are able to produce long-chain polyprenols in yeast. Conclusions T. koksaghyz rubber particles are similar to those described for H. brasiliensis. They contain very pure, high molecular mass

  13. Brush in the bath of active particles: Anomalous stretching of chains and distribution of particles

    Science.gov (United States)

    Li, Hui-shu; Zhang, Bo-kai; Li, Jian; Tian, Wen-de; Chen, Kang

    2015-12-01

    The interaction between polymer brush and colloidal particles has been intensively studied in the last two decades. Here, we consider a flat chain-grafted substrate immersed in a bath of active particles. Simulations show that an increase in the self-propelling force causes an increase in the number of particles that penetrate into the brush. Anomalously, the particle density inside the main body of the brush eventually becomes higher than that outside the brush at very large self-propelling force. The grafted chains are further stretched due to the steric repulsion from the intruded particles. Upon the increase of the self-propelling force, distinct stretching behaviors of the chains were observed for low and high grafting densities. Surprisingly, we find a weak descent of the average end-to-end distance of chains at high grafting density and very large force which is reminiscent of the compression effect of a chain in the active bath.

  14. How does a flexible chain of active particles swell?

    Science.gov (United States)

    Kaiser, Andreas; Babel, Sonja; ten Hagen, Borge; von Ferber, Christian; Löwen, Hartmut

    2015-03-01

    We study the swelling of a flexible linear chain composed of active particles by analytical theory and computer simulation. Three different situations are considered: a free chain, a chain confined to an external harmonic trap, and a chain dragged at one end. First, we consider an ideal chain with harmonic springs and no excluded volume between the monomers. The Rouse model of polymers is generalized to the case of self-propelled monomers and solved analytically. The swelling, as characterized by the spatial extension of the chain, scales with the monomer number defining a Flory exponent ν which is ν = 1/2, 0, 1 in the three different situations. As a result, we find that activity does not change the Flory exponent but affects the prefactor of the scaling law. This can be quantitatively understood by mapping the system onto an equilibrium chain with a higher effective temperature such that the chain swells under an increase of the self-propulsion strength. We then use computer simulations to study the effect of self-avoidance on active polymer swelling. In the three different situations, the Flory exponent is now ν = 3/4, 1/4, 1 and again unchanged under self-propulsion. However, the chain extension behaves non-monotonic in the self-propulsion strength.

  15. Modal and excitation asymmetries in magneto-dielectric particle chains

    CERN Document Server

    Mazor, Y

    2016-01-01

    We study the properties of dipolar wave propagation in linear chains of isotropic particles with independent electric and magnetic response, embedded in vacuum. It is shown that the chain can support simultaneously right-handed modes (RHM) and left-handed modes (LHM) of transverse-polarization. The LHM are supported by the structure even if the chain's particles possess positive polarizabilities and no Bi-isotropy; the needed structural Bi-isotropy is provided by the propagator instead of by the particle's local properties. In contrast to the transverse modes in chains that consist of purely electric particles that are inherently RHM, the LHM dispersion lacks the light-line branch since their dipolar features are not aligned with the electric and magnetic fields of a right-handed plane-wave solution in free space. Furthermore, it is shown that the spatial width of the LHM is significantly smaller than that of the RHM. Excitation theory is developed, and it is shown that the chain possesses modal and excitatio...

  16. Latex Allergy: Tips to Remember

    Science.gov (United States)

    ... Library ▸ Allergy Library ▸ Latex allergy TTR Share | Latex Allergy This article has been reviewed by Thanai Pongdee, ... not contain any natural rubber latex protein. Latex allergy was unusual until the late 1980s when more ...

  17. Latex allergies - for hospital patients

    Science.gov (United States)

    ... latex to be removed from your room The pharmacy and dietary staff to be told about your latex allergy so they do not use latex when they prepare your medicines and food Alternative Names Latex products - hospital; Latex allergy - hospital; Latex sensitivity - hospital; Contact dermatitis - ...

  18. Introduction to LATEX

    International Nuclear Information System (INIS)

    Lecture material on LATEX documentation preparation system, which at the beginning of 1990 was presented to CERN, is given. LATEX computer composition is simple and enables the user to form documents with various standard style (book, article, report, business letter). The main operation principles of LATEX system, which enables to create high quality polygraphic documents containing a lot of mathematical phormulae, are considered

  19. Engineering Multifunctional Living Paints: Thin, Convectively-Assembled Biocomposite Coatings of Live Cells and Colloidal Latex Particles Deposited by Continuous Convective-Sedimentation Assembly

    Science.gov (United States)

    Jenkins, Jessica Shawn

    Advanced composite materials could be revolutionized by the development of methods to incorporate living cells into functional materials and devices. This could be accomplished by continuously and rapidly depositing thin ordered arrays of adhesive colloidal latex particles and live cells that maintain stability and preserve microbial reactivity. Convective assembly is one method of rapidly assembling colloidal particles into thin (engineered compositions, thicknesses, and particle packing that offer several advantages over thicker randomly ordered composites, including enhanced cell stability and increased reactivity through minimized diffusion resistance to nutrients and reduced light scattering. This method can be used to precisely deposit live bacteria, cyanobacteria, yeast, and algae into biocomposite coatings, forming reactive biosensors, photoabsorbers, or advanced biocatalysts. This dissertation developed new continuous deposition and coating characterization methods for fabricating and characterizing 90 hours) photohydrogen production under anoxygenic conditions. Nutrient reduction slows cell division, minimizing coating outgrowth, and promotes photohydrogen generation, improving coating reactivity. Scanning electron microscopy of microstructure revealed how coating reactivity can be controlled by the size and distribution of the nanopores in the biocomposite layers. Variations in colloid microsphere size and suspension composition do not affect coating reactivity, but both parameters alter coating microstructure. Porous paper coated with thin coatings of colloidal particles and cells to enable coatings to be used in a gas-phase without dehydration may offer higher volumetric productivity for hydrogen production. Future work should focus on optimization of cell density, light intensity, media cycling, and acetate concentration.

  20. PREAPARATION OF CATIONIC LATEXES OF POLY(STYRENE-CO-BUTYL ACRYLATE) AND THEIR PROPERTIES EVOLUTION IN LATEX DILUTION

    Institute of Scientific and Technical Information of China (English)

    Dong Zou; Xiu-fen Li; Xiao-li Zhu; Xiang-zheng Kong

    2012-01-01

    Cationic latexes were prepared through emulsion copolymerization of styrene (St) and butyl acrylate (BA) with a cationic surfactant,cetyl trimethyl ammonium bromide (CTAB).Latex properties,including particle size,size distribution,ζ potential,surface tension and monomer conversion,were determined for latexes prepared with different CTAB amounts.Evolution of these properties during emulsion polymerization was followed in order to understand the mechanism of the particles formation.Results showed that both particle size and ζpotential were function of polymerization time and latex solids.Parallel emulsion polymerizations with cationic,anionic charged initiator and charge-free initiators were also carried out,the latex properties were determined at different polymerization time.All these results were attentively interpreted based on the mechanisms of emulsion polymerization,surfactant adsorption and latex particle stabilization.

  1. Latex immunoassay for rapid detection of rotavirus.

    OpenAIRE

    Hughes, J. H.; Tuomari, A V; Mann, D R; Hamparian, V V

    1984-01-01

    A latex agglutination (LA) test was evaluated for the detection of human rotaviruses in stool specimens. Both antiserum and immunoglobulin G (IgG)-sensitized latex particles were used, with IgG-coated beads being more sensitive for human rotavirus antigen detection. Latex beads sensitized with anti-simian-SA-11 IgG were stable for at least 8 months when stored at 4 degrees C. The sensitivity of the test was compared with that of the Rotazyme (Abbott Laboratories, Diagnostics Div., North Chica...

  2. Effect of Gamma Irradiation on Natural and Synthetic Latexes

    International Nuclear Information System (INIS)

    As compared with bulk rubber, rubber particles in latexes vulcanized by irradiation possess specific properties. The properties of synthetic latex particles (SKS-30A and SKN-40) vulcanized by gamma irradiation, and of the films obtained from them, differ in properties they acquire by other vulcanization techniques. Changes in the properties of latex (pH-value, surface tension, viscosity, etc.) as a colloidal system under irradiation depend to a considerable extent upon the chemical nature of the rubber and on its derivation. Yields differ according to whether the vulcanization is carried out by particle or by bulk irradiation. Ageing processes for such latexes and the films obtained from them differ from ageing processes for non-vulcanized or sulphur-vulcanized latexes. The radiation vulcanized products have increased stability. The properties of the vulcanized rubber in the latex are confirmed by data indicating high resolution nuclear magnetic resonance spectra. (author)

  3. Markov chain model for particle migration at the repository scale

    International Nuclear Information System (INIS)

    A model for particle migration at multiple scales is developed using the Markov chain probability model. The goal of the model is to enable analyses of radionuclide migration at the repository scale based on the information obtained in smaller-scale detailed analyses by other models. Geologic domain is divided into an array of compartments, and particle migration is simulated by transitions from one compartment to another based on transition probabilities. Nuclide transport in hypothetical repository with heterogeneous flow due to random connectivity between compartments is demonstrated. In the comparison with the analytical continuum model of mass transport, the results from the present model show a good agreement. (author)

  4. Colloid stable sorbents for cesium removal: preparation and application of latex particles functionalized with transition metals ferrocyanides.

    Science.gov (United States)

    Avramenko, Valentin; Bratskaya, Svetlana; Zheleznov, Veniamin; Sheveleva, Irina; Voitenko, Oleg; Sergienko, Valentin

    2011-02-28

    In this paper we suggest a principally new approach to preparation of colloid stable selective sorbents for cesium uptake using immobilization of transition metals (cobalt, nickel, and copper) ferrocyanides in nanosized carboxylic latex emulsions. The effects of ferrocyanide composition, pH, and media salinity on the sorption properties of the colloid stable sorbents toward cesium ions were studied in solutions containing up to 200 g/L of sodium nitrate or potassium chloride. The sorption capacities of the colloid sorbents based on mixed potassium/transition metals ferrocyanides were in the range 1.3-1.5 mol Cs/mol ferrocyanide with the highest value found for the copper ferrocyanide. It was shown that the obtained colloid-stable sorbents were capable to penetrate through bulk materials without filtration that made them applicable for decontamination of solids, e.g. soils, zeolites, spent ion-exchange resins contaminated with cesium radionuclides. After decontamination of liquid or solid radioactive wastes the colloid-stable sorbents can be easily separated from solutions by precipitation with cationic flocculants providing localization of radionuclides in a small volume of the precipitates formed. PMID:21208744

  5. PREPARATION AND STABILITY OF POLYSTYRENE LATEXES USING POLYSOAPS AS EMULSIFIERS

    NARCIS (Netherlands)

    YANG, YJ; ENGBERTS, JBFN

    1992-01-01

    Microemulsions of styrene can be polymerized at 70-degrees in the presence of polysoaps as emulsifiers to produce stable polystyrene latexes. The effects of polymerization conditions on the molecular weights, molecular weight distribution, particle size and particle size distribution of the latexes

  6. Drying of latex films and coatings: Reconsidering the fundamental mechanisms

    DEFF Research Database (Denmark)

    Kiil, Søren

    2006-01-01

    The two existing theories describing drying of latex films or coatings are reconsidered. Subsequently, a novel mathematical drying model is presented, the simulations of which can match and explain experimental drying rate data of two previous investigations with latex films. In contrast to...... previous model studies, but in agreement with observations, simulations suggest that during the falling rate period of the drying process of a latex film, a porous skin of partly coalesced latex particles is indeed formed, which limits transport of water vapour from the receding air-liquid interphase to......-1322 mu m), latex particle size (500-600 nm), initial polymer volume concentration (19-47 vol.%), and molecular weight of latex polymer (not quantified). Simulations also demonstrate that the transition from a constant to a falling drying rate in all cases takes place when the polymer volume concentration...

  7. Latex Allergy: A Prevention Guide

    Science.gov (United States)

    ... Topics Publications and Products Programs Contact NIOSH Latex Allergy A Prevention Guide Recommend on Facebook Tweet Share ... proteins that cause allergic reactions. What is latex allergy? Latex allergy is a reaction to certain proteins ...

  8. Study on Soap-free P(MMA-EA-AA/MAA) Latex Particles With Narrow Size Distribution

    Institute of Scientific and Technical Information of China (English)

    K. Kang; C. Y. Kan; Y. Du; D. S. Liu

    2005-01-01

    @@ 1Introduction In the past decades, more and more studies have been focused on the synthesis of monodisperse particles with different diameter by special polymerization technique. In 1980' s, Ugelstad, et al[1] invented two-step swelling method to prepare monodisperse microsphere with large size more than 1 μm. In the following decade, Okubo and his coworkers[2] synthesized monodisperse crosslinked polymer particles above 3 μm using one-step dynamic swelling method. New method has been developed to produce particles more than 50 μm in diameter with a standard deviation of less than 2%[3]. Up to now, most of the monodisperse particles were usually prepared by polymerization of St in the presence of surfactants. In this presentation, sub-micro sized P (MMA-EA-AA/MAA) particles with narrow size distribution were prepared by seeded emulsion polymerization in the absence of any surfactant materials.

  9. PREPARATION AND PROPERTIES OF SILICONE-ACRYLATE COPOLYMER LATEX

    Institute of Scientific and Technical Information of China (English)

    Mu-jie Yang; Wei Zhang

    2004-01-01

    Silicone-acrylate copolymer latex was prepared through three different polymerization processes, i.e., the batch process, preemulsified monomer addition and the monomer addition process. The results revealed that the monomer addition process is a desirable approach to produce narrow particle size distribution latex with higher polymerization conversion and less amount of coagulum. The effect of silicone content on the glossiness and water absorption of latex film was investigated and the results showed that the glossiness of latex film is improved up to a silicone content of 10% of total monomers, but becomes impaired thereafter, whereas water absorption is reduced accordingly.

  10. Radiation-induced grafting polymerization of MMA onto polybutadiene rubber latex

    International Nuclear Information System (INIS)

    The grafting of methyl methacrylate (MMA) onto polybutadiene rubber latex by the direct radiation method was carried out. The effects of monomer concentration, absorbed dose and dose rate of gamma rays on the grafting yield were investigated. The graft copolymers were characterized by transmission electron microscopy (TEM), FTIR spectroscopy, and differential scanning calorimetry. TEM photographs revealed that the core-shell structures of latex particles are formed at low MMA content, and with the increasing of MMA content, the semi-IPN-like structure with core-shell could be developed due to the high gel fraction of polybutadiene (PBD) seed particles. In addition, infrared analysis confirmed that MMA could be grafted onto PBD molecular chains effectively under appropriate irradiation conditions. The interfacial adhesion between PBD rubber (core) and PMMA (shell) phases could be enhanced with the increase of MMA concentration

  11. Latex in the Hospital Environment

    Science.gov (United States)

    LATEX in the Hospital Environment Updated Fall 2015 This list provides a guide to some of the most common objects containing latex and offers some ... remover–Sepha Pharm) 1 LATEX in the Hospital Environment (continued) Frequently contains LATEX OR/Infection Control masks, ...

  12. Parametrization of Chain Molecules in Dissipative Particle Dynamics.

    Science.gov (United States)

    Lee, Ming-Tsung; Mao, Runfang; Vishnyakov, Aleksey; Neimark, Alexander V

    2016-06-01

    This paper presents a consistent strategy for parametrization of coarse-grained models of chain molecules in dissipative particle dynamics (DPD), where the soft-core DPD interaction parameters are fitted to the activities in solutions of reference compounds that represent different fragments of target molecules. The intercomponent parameters are matched either to the infinite dilution activity coefficients in binary solutions or to the solvent activity in polymer solutions. The respective calibration relationships between activity and intercomponent interaction parameter are constructed from the results of Monte Carlo simulation of the coarse-grained solutions of reference compounds. The chain conformation is controlled by the near neighbor and second neighbor bond potentials, which are parametrized by fitting the intramolecular radial distribution functions of the coarse-grained chains to the respective atomistic molecular dynamics simulations. The consistency, accuracy, and transferability of the proposed parametrization strategy is demonstrated drawing on the example of nonionic surfactants of the poly(ethylene oxide) alkyl ether (CnEm) family. The lengths of tail and head sequences are varied (n = 8-12 and m = 3-9), so that the critical micelle concentration ranges from 10 to 0.1 mM. The surfactants are modeled at different coarse-graining levels using DPD beads of different diameters. We found consistent agreement with experimental data for the critical micelle concentration and aggregation number, especially for surfactants with relatively long hydrophilic segments. Depending on the system, we observed surfactant aggregation into spheroidal, elongated, or core-shell micelles, as well as into irregular agglomerates. Using the models at different coarse-graining levels for the same molecules, we found that the smaller the bead size the better is agreement with experimental data. PMID:27167160

  13. Production of latex agglutination reagents for pneumococcal serotyping

    Directory of Open Access Journals (Sweden)

    Ortika Belinda D

    2013-02-01

    Full Text Available Abstract Background The current ‘gold standard’ for serotyping pneumococci is the Quellung test. This technique is laborious and requires a certain level of training to correctly perform. Commercial pneumococcal latex agglutination serotyping reagents are available, but these are expensive. In-house production of latex agglutination reagents can be a cost-effective alternative to using commercially available reagents. This paper describes a method for the production and quality control (QC of latex reagents, including problem solving recommendations, for pneumococcal serotyping. Results Here we describe a method for the production of latex agglutination reagents based on the passive adsorption of antibodies to latex particles. Sixty-five latex agglutination reagents were made using the PneuCarriage Project (PCP method, of which 35 passed QC. The other 30 reagents failed QC due to auto-agglutination (n=2, no reactivity with target serotypes (n=8 or cross-reactivity with non-target serotypes (n=20. Dilution of antisera resulted in a further 27 reagents passing QC. The remaining three reagents passed QC when prepared without centrifugation and wash steps. Protein estimates indicated that latex reagents that failed QC when prepared using the PCP method passed when made with antiserum containing ≤ 500 μg/ml of protein. Sixty-one nasopharyngeal isolates were serotyped with our in-house latex agglutination reagents, with the results showing complete concordance with the Quellung reaction. Conclusions The method described here to produce latex agglutination reagents allows simple and efficient serotyping of pneumococci and may be applicable to latex agglutination reagents for typing or identification of other microorganisms. We recommend diluting antisera or removing centrifugation and wash steps for any latex reagents that fail QC. Our latex reagents are cost-effective, technically undemanding to prepare and remain stable for long periods of

  14. Characteristics of natural rubber latex from Indonesia

    International Nuclear Information System (INIS)

    Five field latexes from different clones have been characterized. The total solid content increases and the protein content decreases with increasing the age of rubber trees. The average particle size is between 190 and 234 nm. The number average molecular weight varies from 160,000 to 700,000 while the weight average molecular weight varies from 1,000,000 to 500,000. Negligivle difference was observed in the physical properties of rubber films prepared from the irradiated field latexes. (author)

  15. Experimental determination of particle size distributions in colloidal systems by dynamic light scattering. Application to polystyrene latex spheres and to nonionic microemulsions

    NARCIS (Netherlands)

    Eshuis, A.; Harbers, G.; Doornink, D.J.; Mijnlieff, P.F.

    1985-01-01

    Information about polydisperse colloidal systems was obtained by dynamic light scattering. The correlation functions obtained were analyzed by the histogram method and the method of cumulants. The former was, as a test, applied to a nearly monodispere polystyrene latex. The agreement between the obt

  16. MORPHOLOGICAL OBSERVATION OF SINGLE-CHAIN POLY(METHYL METHACRYLATE) PARTICLES

    Institute of Scientific and Technical Information of China (English)

    NI Ming; CHEN Liusheng; JIA Shijun; JIN Xigao; GE Shouren; Atsushi TAKAHARA; Tisato KAJIYAMA

    1997-01-01

    Tapping mode atomic force microscope has been applied to observe single-chain PMMA particles which were stored for six months at room temperature after sprayed from very dilute solutions in good solvents, good/poor mixed solvents, and a theta solvent. Monodisperse PMMA standards of molecular weights ranging from 7.90 × 104 to 1.3 × 106 were used to investigate the effect of molecular weight on the size of the single-chain PMMA particles. These single-chain particles showed close to spherical shapes. The morphology of single-chain PMMA particles of a given molecular weight was found to be identical in spite of different solvents used for solution spraying. Molecular weight dependence of the particle dimension was also found. The diameters of single-chain PMMA particles after correction of tip-geometry effect were compared to the values estimated from molecular weight and density.

  17. Application of Latex particles in detecting alpha- fetoprotein (AFP)%乳胶粒子法检测甲胎蛋白的应用

    Institute of Scientific and Technical Information of China (English)

    陈浩全; 曾嫚妮

    2012-01-01

    Objective:To evaluate the application value of Latex method in detection of alpha - fetoprotein ( AFP). Methods:Repetitive determination tests within and between batches were done on serum specimens, then the determination results were compared and analyzed by Latex method and electrochemiluminescence assay. Results; The results had no significant difference between Latex method and electrochemiluminescence assay, the recoveries were 95.5% for Latex method and 96.7% for electrochemiluminescence assay. Conclusion; Though electrochemiluminescence assay had high sensitivity and precision, it was not suitable for the wide use due to its high cost in instrument and reagent. Latex method had good correlation with electrochemiluminescence assay, which can be applied widely for its rapidness, stable results and low cost.%目的:评价Latex法检测甲胎蛋白(AFP)的临床应用价值.方法:对血清标本做批内批间重复性测定试验及Latex法与电化学发光法进行对比测定.结果:Latex法与电化学发光法检测AFP结果无显著差异,Latex法与电化学发光法平均回收率分别为95.5%和96.7%.结论:电化学发光法灵敏度、精密度高,但其仪器、试剂价格高,不适于全面推广;Latex法与电化学发光法检测AFP结果无显著差异,相关性好,快速、结果稳定,试剂便宜在全自动生化仪上检测,可广泛应用.

  18. Effect of cationic monomer on properties of fluorinated acrylate latex

    Institute of Scientific and Technical Information of China (English)

    Li Jun Chen

    2012-01-01

    Cationic fluorinated acrylate latex was prepared via semi-continuous emulsion copolymerization of cationic monomer and other monomers.The resultant latex and its film were characterized with dynamic light scattering detector and contact angle meter.Influences of amount of DMDAAC on the properties of resultant latex and its film were investigated in detail.Results show that the particle size of the latex has the minimum value and the zeta potential of the latex is increased when the amount of DMDAAC is increased.In addition,the particle size of the latex is unimodal distribution when the amount of DMDAAC is not more than 2.5%.However,the particle size of the latex is bimodal distribution when the amount of DMDAAC is more than 2.5%.The contact angle is varied slightly with the increase of amount of DMDAAC when it is not more than 2.5%.Nevertheless,the contact angle is decreased with the increase of the amount of DMDAAC when it is more than 25%.

  19. Mechanics of semiflexible chains formed by poly(ethylene glycol)-linked paramagnetic particles

    Science.gov (United States)

    Biswal, Sibani Lisa; Gast, Alice P.

    2003-08-01

    Magnetorheological particles, permanently linked into chains, provide a magnetically actuated means to manipulate microscopic fluid flow. Paramagnetic colloidal particles form reversible chains by acquiring dipole moments in the presence of an external magnetic field. By chemically connecting paramagnetic colloidal particles, flexible magnetoresponsive chains can be created. We link the paramagnetic microspheres using streptavidin-biotin binding. Streptavidin coated microspheres are placed in a flow cell and a magnetic field is applied, causing the particles to form chains. Then a solution of polymeric linkers of bis-biotin-poly(ethylene glycol) molecules is added in the presence of the field. These linked chains remain responsive to a magnetic field; however, in the absence of an external magnetic field these chains bend and flex due to thermal motion. The chain flexibility is determined by the length of the spacer molecule between particles and is quantified by the flexural rigidity or bending stiffness. To understand the mechanical properties of the chains, we use a variety of optical trapping experiments to measure the flexural rigidity. Increasing the length of the poly(ethylene glycol) chain in the linker increases the flexibility of the chains.

  20. More math into Latex

    CERN Document Server

    Grätzer, George

    2007-01-01

    For close to two decades, Math into Latex has been the standard introduction and complete reference for writing articles and books containing mathematical formulas. In this fourth edition, the reader is provided with important updates on articles and books. An important new topic is discussed: transparencies (computer projections). Key features of More Math into Latex, 4th edition: Installation instructions for PC and Mac users; An example-based, visual approach and a gentle introduction with the Short Course; A detailed exposition of multiline math formulas with a Visual Guide; A unified appr

  1. Latex and friends

    CERN Document Server

    Dongen, M R C van

    2012-01-01

    LaTeX is a free, automated state-of-the-art typesetting system. This book teaches all the ins and outs of LaTeX which are needed to write an article, report, thesis, or book. The book teaches by example, giving many worked out examples showing input and output side by side. The book presents the most recent techniques for presenting data plots, complex graphics, and computer presentations, but does not require previous knowledge. However, it is also a reference for the more seasoned user, with pointers to modern techniques and packages. Recurring themes in the book are consistent and effective

  2. Aqueous Tape Casting Process with Styrene-acrylic Latex Binder

    Institute of Scientific and Technical Information of China (English)

    CUI Xue-min; OUYANG Shi-xi; HUANG Yong; YU Zhi-yong; ZHAO Shi-ke; WANG Chang-an

    2004-01-01

    A commercial styrene-acrylic latex binder has been investigated as a good binder for aqueous Al2O3 suspensions tape-casting process. This paper focuses on the forming film mechanism of latex binder, the rheological behaviors of the suspensions, physical properties of green tapes and drying process of aqueous slurries with latex binder system. The drying process of the alumina suspensions is shown to follow a two-stage mechanism (the first stage: evaporation controlled process; and the second stage: diffusion controlled process). During the drying stage of the suspensions, the compressive force presses the latex particles and makes them be distorted, which results in cross-linking structure in contacted latex particles of the solidified tapes.A smooth-surface and high-strength green tape was fabricated by aqueous tape casting with latex binder system. The results from the SEM images of the crossing section microstructure of green tapes show that the latex is a very suitable binder for aqueous tape casting.

  3. Latex medical gloves

    DEFF Research Database (Denmark)

    Palosuo, Timo; Antoniadou, Irini; Gottrup, Finn;

    2011-01-01

    Many hospitals have implemented policies to restrict or ban the use of devices made of natural rubber latex (NRL) in healthcare as precautionary measures against the perceived risk of NRL allergy. Changes in glove technology, progress in measuring the specific allergenic potential of gloves and a...

  4. Standardization of radiation vulcanized natural rubber latex

    International Nuclear Information System (INIS)

    Standards for concentrated latex used in the preparation of irradiated latex, standard irradiation conditions, further treatment of irradiated latex, level of prevulcanization and its estimation, film preparation and testing procedures are discussed in this paper. (author)

  5. Research on Demand Prediction of Fresh Food Supply Chain Based on Improved Particle Swarm Optimization Algorithm

    Directory of Open Access Journals (Sweden)

    He Wang

    2015-04-01

    Full Text Available Demand prediction of supply chain is an important content and the first premise in supply management of different enterprises and has become one of the difficulties and hot research fields for the researchers related. The paper takes fresh food demand prediction for example and presents a new algorithm for predicting demand of fresh food supply chain. First, the working principle and the root causes of the defects of particle swarm optimization algorithm are analyzed in the study; Second, the study designs a new cloud particle swarm optimization algorithm to guarantee the effectiveness of particles in later searching phase and redesigns its cloud global optimization searching method and crossover operation; Finally, a certain fresh food supply chain is taken for example to illustrate the validity and feasibility of the improved algorithm and the experimental results show that the improved algorithm can improve prediction accuracy and calculation efficiency when used for demand prediction of fresh food supply chain.

  6. Particle Markov Chain Monte Carlo Techniques of Unobserved Component Time Series Models Using Ox

    DEFF Research Database (Denmark)

    Nonejad, Nima

    This paper details Particle Markov chain Monte Carlo techniques for analysis of unobserved component time series models using several economic data sets. PMCMC combines the particle filter with the Metropolis-Hastings algorithm. Overall PMCMC provides a very compelling, computationally fast and...

  7. Measurements of Particle Size Distribution Based on Mie Scattering Theory and Markov Chain Inversion Algorithm

    Directory of Open Access Journals (Sweden)

    Zi Ye

    2012-10-01

    Full Text Available Measuring particle size distribution through calculating light scattering intensity is a typical inverse problem. This paper builds an inverse mathematical model based on Mie scattering, deduces the inversion formulas for particle size, and calculates the relative coefficients through programming with built-in functions in MATLAB. In order to improve the accuracy and noise immunity of particle size distribution measurement, the development of stochastic inversion algorithm: an inverse problem model based on Markov chain algorithm is proposed. Results of numerical simulation are added acceptable noise indicate that the algorithm of Markov chain has strong noise immunity and can meet the requirements of on-line measurement.

  8. Critical single domain grain sizes in chains of interacting greigite particles: implications for magnetosome crystals

    OpenAIRE

    Muxworthy, Adrian; Williams, Wyn; Roberts, Andrew; Winklhofer, Michael; Chang, Liao; Pósfai, Mihály

    2013-01-01

    Magnetotactic bacteria contain chains of magnetically interacting crystals (magnetosomes), which aid navigation (magnetotaxis). To improve the efficiency of magnetotaxis, magnetosome crystals (which can consist of magnetite or greigite) should be magnetically stable single domain (SD) particles. Larger particles subdivide into non-uniform multi-domain (MD) magnetic structures that produce weaker magnetic signals, while small SD particles become magnetically unstable due to thermal fluctuation...

  9. Transport and selective chaining of bidisperse particles in a travelling wave potential.

    Science.gov (United States)

    Tierno, Pietro; Straube, Arthur V

    2016-05-01

    We combine experiments, theory and numerical simulation to investigate the dynamics of a binary suspension of paramagnetic colloidal particles dispersed in water and transported above a stripe-patterned magnetic garnet film. The substrate generates a one-dimensional periodic energy landscape above its surface. The application of an elliptically polarized rotating magnetic field causes the landscape to translate, inducing direct transport of paramagnetic particles placed above the film. The ellipticity of the applied field can be used to control and tune the interparticle interactions, from net repulsive to net attractive. When considering particles of two distinct sizes, we find that, depending on their elevation above the surface of the magnetic substrate, the particles feel effectively different potentials, resulting in different mobilities. We exploit this feature to induce selective chaining for certain values of the applied field parameters. In particular, when driving two types of particles, we force only one type to condense into travelling parallel chains. These chains confine the movement of the other non-chaining particles within narrow colloidal channels. This phenomenon is explained by considering the balance of pairwise magnetic forces between the particles and their individual coupling with the travelling landscape. PMID:27194527

  10. Decontamination of latex gloves

    International Nuclear Information System (INIS)

    Initially the latex gloves used in controlled zones were processed after use as radioactive waste. In view of the continually increasing number used, however, the persons in charge of the SPRAR have considered the possibility of decontaminating the gloves and using them again after control. The recovery installations which have been developed were initially designed rather crudely and operated irregularly; they have been progressively improved as a result of the experience acquired; today they are more really an industrial concern, equipped with automatic machinery. In 1967 it has been possible with this set-up to recover 247000 pairs of gloves, representing nearly 70 per cent of the number treated. (author)

  11. Effect of heterogeneous distribution of crosslink density on physical properties of radiation vulcanized NR (Natural Rubber) latex film

    International Nuclear Information System (INIS)

    Thus a study has been carried out to investigate the effect of particle to particle variation in crosslink density on physical properties of radiation vulcanized NR latex film. NR latex was irradiated in small bottle by γ rays without vulcanization accelerator to provide latex rubber particles having homogeneous distribution of crosslink density. The doses were 30, 50, 100, 250, 300, 400, 500 and 600 kGy. Weight swelling ratio, gel fraction, tensile strength and elongation at break of the latex film from the mixed latex were measured. The vulcanization dose of this latex was 250 kGy. Then the two different latexes were mixed in a such way to adjust the average dose of 250 kGy to prepare a latex consisting of rubber particles having heterogeneous distribution of crosslink density. Tensile strength of the latex film was depressed by mixing. The reduction increased with increasing the decrease of gel fraction by mixing. However the reduction was not serious when the dose difference of two latexes was less than 200 kGy

  12. Critical single domain grain sizes in chains of interacting greigite particles: Implications for magnetosome crystals

    Science.gov (United States)

    Muxworthy, Adrian R.; Williams, Wyn; Roberts, Andrew P.; Winklhofer, Michael; Chang, Liao; Pósfai, Mihály

    2013-12-01

    Magnetotactic bacteria contain chains of magnetically interacting crystals (magnetosomes), which aid navigation (magnetotaxis). To improve the efficiency of magnetotaxis, magnetosome crystals (which can consist of magnetite or greigite) should be magnetically stable single domain (SD) particles. Larger particles subdivide into nonuniform multidomain (MD) magnetic structures that produce weaker magnetic signals, while small SD particles become magnetically unstable due to thermal fluctuations and exhibit superparamagnetic (SP) behavior. In this study, we determined the stable SD range as a function of grain elongation and interparticle separation for chains of identical greigite grains using fundamental parameters recently determined for greigite. Interactions significantly increase the stable SD range. For example, for cube-shaped greigite grains the upper stable SD threshold size is increased from 107 nm for isolated grains to 204 nm for touching grains arranged in chains. The larger critical SD grain size for greigite means that, compared to magnetite magnetosomes, greigite magnetosomes can produce larger magnetic signals without the need for intergrain interactions.

  13. Novel latex agglutination method with chicken anti-protein A for detection of Staphylococcus aureus infections.

    OpenAIRE

    Larsson, A; Sjöquist, J

    1989-01-01

    A latex agglutination assay for the detection of protein A-secreting Staphylococcus aureus strains or strains with protein A in the cell wall is described. The assay utilizes latex particles coated with chicken anti-protein A antibodies. Chicken antibodies do not react with protein G-producing streptococci or rheumatoid factor, thus avoiding false-positive reactions.

  14. Pose control of the chain composed of magnetic particles using external uniform and gradient magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, J. F., E-mail: zhoujianfeng@njtech.edu.cn; Shao, C. L.; Gu, B. Q. [Nanjing Tech University, School of Mechanical and Power Engineering (China)

    2016-01-15

    Magnetic particles (MPs) are known to respond to a magnetic field and can be moved by magnetic force, which make them good carriers in bioengineering and pharmaceutical engineering. In this paper, a pose control method for the straight chain composed of MPs is proposed, and the chain with one pose can be moved to another position with another pose using alternately employed uniform and gradient magnetic fields. Based on computer simulations, it is revealed that in the uniform magnetic field, the MPs form a straight chain with the same separation space along the field lines, and once the uniform magnetic field rotates, the chain also rotates with the field. In the gradient magnetic field, the MPs move toward the higher field so that the translation of the chain can be realized. The simulation results indicate that while the uniform magnetic field is rotating, there exists certain hysteresis between the chain and the field, and the chain is not straight anymore. So the uniform magnetic field should rest at the target angle for a period to make the chain fully relax to be straight. For nanoMP, its magnetic moment directly determines the gradient magnetic force which is much smaller than the dipole–dipole force among MPs. Therefore, the translation of the chain is much more time-consuming than rotation. To enlarge the translational velocity, it is suggested to increase the size of MPs or the magnetic field gradient.

  15. Antimicrobial activity of latex silver nanoparticles using Calotropis procera

    Institute of Scientific and Technical Information of China (English)

    Nadia; Hussein; Mohamed; Mady; Ahmed; Ismail; Wael; Moustfa; Abdel-Mageed; Ahmed; Abdelfattah; Mohamed; Shoreit

    2014-01-01

    Objective:To synthesize silver nanoparticles(AgNPs) by green methods using scrum latex of Calotropis procera at 80 ℃ and evaluate them against bacteria,dermatophytes and phytopathogenic fungi comparing with the activity of untreated latex.Methods:The synthesis of AgNPs was performed by mixing 3%latex scrum extract with the same volume of silver nitrate(2 mmol/L) solution in round flask and heating in water bath at80 ℃.Characterization of silver particles were determined using UV-vis spectrophotometer,transmission electron microscopy(TEM),X-ray diffraction and Fourier transform infrared spectroscopy.The antimicrobial activity of the green synthesized AgNPs was determined against bacteria,dermatophytes and phytopathogenic fungi and compared to the crude untreated latex by agar-well diffusion methods.Results:Biosynthesis of latex silver nanoparticles was successfully obtained by green method.The formation of AgNPs has been confirmed by UV-vis,TEM microscopy.X-ray diffraction and Fourier transform infrared spectroscopy.TEM analysis showed that synthesized AgNPs are highly stable spherical shaped particles,well dispersed with a diameter ranged from 4 nm up to 25 nm and an average size of 12.33 nm.AgNPs showed strong antibacterial activity against Gram-negative bacteria(Escherichia coli,Pseudomonas aeruginosa and Serratia sp.) and antifungal activity against Trichophyton rubrum,Candida albicans and Aspergillus terreus.Conclusions:It can be concluded that serum latex of Calotropis pmcera was found to display strong potential for the synthesis of AgNPs as antimicrobial agents through rapid reduction of silver ions(Ag~+ to Ag~0).The green synthesized AgNPs were found to show higher antimicrobial efficacy than crude latex.

  16. Inference in Kingman's Coalescent with Particle Markov Chain Monte Carlo Method

    OpenAIRE

    Chen, Yifei; Xie, Xiaohui

    2013-01-01

    We propose a new algorithm to do posterior sampling of Kingman's coalescent, based upon the Particle Markov Chain Monte Carlo methodology. Specifically, the algorithm is an instantiation of the Particle Gibbs Sampling method, which alternately samples coalescent times conditioned on coalescent tree structures, and tree structures conditioned on coalescent times via the conditional Sequential Monte Carlo procedure. We implement our algorithm as a C++ package, and demonstrate its utility via a ...

  17. Transmittance tuning by particle chain polarization in electrowetting-driven droplets

    OpenAIRE

    Fan, Shih-Kang; Chiu, Cheng-Pu; Huang, Po-Wen

    2010-01-01

    A tiny droplet containing nano∕microparticles commonly handled in digital microfluidic lab-on-a-chip is regarded as a micro-optical component with tunable transmittance at programmable positions for the application of micro-opto-fluidic-systems. Cross-scale electric manipulations of droplets on a millimeter scale as well as suspended particles on a micrometer scale are demonstrated by electrowetting-on-dielectric (EWOD) and particle chain polarization, respectively. By applying electric field...

  18. γ irradiation of carboxylated styrene-butadiene rubber latex

    International Nuclear Information System (INIS)

    The crosslinking behavior of carboxylated styrene-butadiene rubber latex (CSBRL) by using gamma radiation with 2-ethyl hexyl acrylate (2-EHA) as crosslinking sensitizer has been studied in detail. In addition, the variation of the particle size and distribution of latex, chemical structure and thermal property of CSBRL with absorbed dose have been discussed. Also the radiation vulcanization mechanism of CSBRL has been suggested. The experiments showed that, the dose rate has small effect on the cross-link behavior of CSBRL, and the swelling ratio decreased rapidly with the increase of absorbed dose. Increasing the dose, the average molecular weight per crosslinked units (Mc) decreased and crosslinking density increased. When the dose is below 25 kGy, no significant changes in the particle size and distribution of latex were observed. The micro-FTIR analysis and DSC curves confirmed the existence of grafting reaction accompanying the crosslinking reaction during the gamma irradiation with 2-EHA as sensitizer

  19. Preparation of MMA-BA-DMAEMA Nanosized Latex

    Institute of Scientific and Technical Information of China (English)

    Yu Yang LIU; Mu Jie YANG

    2003-01-01

    The terpolymer latex of methyl methacrylate (MMA)/butyl acrylate (BA)/ dimethyl aminoethyl methacrylate (DMAEMA) with diameter of less than 100 nm was prepared by seeding semi-continuous emulsion copolymerization using APS (ammonium persulfate) / TMEDA (N,N,N, N-tetramethylethylenediamine) as the redox initiators and SDS (sodium dodecylsulfate) and OP (P-octylpolyethylene glycol phenylether) as co-emulsifiers. The factors that influenced the process stability of the copolymerization and the particle size of the latex were investigated. The addition of aqueous ammonia as coagulation inhibitor provided better process stability of the copoly- merization. The addition of acetic acid as the acidification agent caused a remarkable reduction of the latex particle size.

  20. STUDY ON SYNTHESIS OF SELF CORSS LINKED POLYSTYRENE LATEX MICROSPHERES

    Institute of Scientific and Technical Information of China (English)

    DaiLizong; ZouYousi; 等

    1997-01-01

    Emulsifier-free emulsion polymerization of styrene in the presence of β-hydroxy propyl acrylate was studied.The emulsifier-free self cross linked polystyrene latex microspheres was obtained.Monomer conversion is higher than 90% when [St],[β-HPA],[KPS] is 2.66,0.228,and 5.8×10-3mol/L respectively under 80℃ for 5h.The mono-dispersed latex particle diameter and colloidal particle concentration were given as D=0.23um,N=3.13×1013/cm3 by TEM analyse,The factors of influencing latex stability were discussed.Thecopolymer was characterized by IR and dissolution experiment.The apparent activation energy of polymerization and polymerization rate constant were obtained to be 78.7KJ/mol and 514.4/mol.s respectively.

  1. Dynamics of particle sedimentation in viscoelastic fluids: A numerical study on particle chain in two-dimensional narrow channel

    CERN Document Server

    Pan, Tsorng-Whay

    2016-01-01

    In this article we present a numerical method for simulating the sedimentation of circular particles in two-dimensional channel filled with a viscoelastic fluid of FENE-CR type, which is generalized from a domain/distributed Lagrange multiplier method with a factorization approach for Oldroyd-B fluids developed in [J. Non-Newtonian Fluid Mech. 156 (2009) 95]. Numerical results suggest that the polymer extension limit L for the FENE-CR fluid has no effect on the final formation of vertical chain for the cases of two disks and three disks in two-dimensional narrow channel, at least for the values of L considered in this article; but the intermediate dynamics of particle interaction before having a vertical chain can be different for the smaller values of L when increasing the relaxation time. For the cases of six particles sedimenting in FENE-CR type viscoelastic fluid, the formation of chain of 4 to 6 disks does depend on the polymer extension limit L. For the smaller values of L, FENE-CR type viscoelastic flu...

  2. Kerr constant of multi-subunit particles and semiflexible, wormlike chains

    Energy Technology Data Exchange (ETDEWEB)

    GarcIa de la Torre, J; Diaz Banos, F G; Perez Sanchez, H E, E-mail: jgt@um.e [Departamento de Quimica Fisica, Facultad de Quimica, Universidad de Murcia, 30071 Murcia (Spain)

    2010-12-15

    A formalism is developed for the Kerr constant of particles composed of subunits whose electro-optical properties have axial symmetry. A protocol is devised for the calculation of the Kerr constant from the dipole moments and the electrical and optical polarizabilities of the subunits. The conformational average is required if the particle is flexible. Based on that formalism, the Kerr constant of semiflexible, wormlike chains is calculated with the help of a discrete version to which the previous formalism is applied. The required conformational averages are evaluated by means of Monte Carlo simulation. Thus we obtain expressions for the Kerr constant of wormlike particles over the whole range of conformations.

  3. Preparation of magnetic latexes functionalized with chloromethyl groups via emulsifier-free miniemulsion polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Faridi-Majidi, Reza [School of Chemistry, University College of Science, Tehran University, Tehran (Iran, Islamic Republic of)]. E-mail: refaridi@khayam.ut.ac.ir; Sharifi-Sanjani, Naser [School of Chemistry, University College of Science, Tehran University, Tehran (Iran, Islamic Republic of)

    2007-04-15

    Functionalized crosslinked polystyrene-co-divinylbenzene-co-chloromethylstyrene magnetic latex particles were prepared via emulsifier-free miniemulsion polymerization using 2, 2' azobis (2-amidinopropane) dihydrochloride (V-50) as an initiator and in the presence of magnetite nanoparticles in the monomers. Transmission electron microscopy (TEM) proved the presence of magnetite nanoparticles in polymer particles. Differential scanning calorimetery (DSC) analysis of the product showed an exothermic signal due to crosslinking of chains through electrophilic aromatic substitution of phenyl groups with chloromethyl groups in the presence of the dispersed Fe{sub 3}O{sub 4} as Lewis acid. This was proven by thermogravimetric analysis (TGA) via the loss of gaseous HCl. The results were also compared with those of magnetite-free miniemulsion polymerization using V-50.

  4. Latex allergy and filaggrin null mutations

    DEFF Research Database (Denmark)

    Carlsen, Berit C; Meldgaard, Michael; Hamann, Dathan;

    2011-01-01

    Objectives Natural rubber latex (NRL) contains over 200 proteins of which 13 have been identified as allergens and the cause of type I latex allergy. Health care workers share a high occupational risk for developing latex allergy. Filaggrin null mutations increase the risk of type I sensitizations...... to aeroallergens and it is possible that filaggrin null mutations also increase the risk of latex allergy. The aim of this paper was to examine the association between filaggrin null mutations and type I latex allergy. Methods Twenty latex allergic and 24 non-latex allergic dentists and dental...... assistants, occupationally exposed to latex, were genotyped for filaggrin null mutations R501X and 2282del4. Latex allergy was determined by a positive reaction or a historical positive reaction to a skin prick test with NRL. Results 41 individuals were successfully genotyped. Three individuals were...

  5. Consistent model reduction of polymer chains in solution in dissipative particle dynamics: Model description

    KAUST Repository

    Moreno, Nicolas

    2015-06-30

    We introduce a framework for model reduction of polymer chain models for dissipative particle dynamics (DPD) simulations, where the properties governing the phase equilibria such as the characteristic size of the chain, compressibility, density, and temperature are preserved. The proposed methodology reduces the number of degrees of freedom required in traditional DPD representations to model equilibrium properties of systems with complex molecules (e.g., linear polymers). Based on geometrical considerations we explicitly account for the correlation between beads in fine-grained DPD models and consistently represent the effect of these correlations in a reduced model, in a practical and simple fashion via power laws and the consistent scaling of the simulation parameters. In order to satisfy the geometrical constraints in the reduced model we introduce bond-angle potentials that account for the changes in the chain free energy after the model reduction. Following this coarse-graining process we represent high molecular weight DPD chains (i.e., ≥200≥200 beads per chain) with a significant reduction in the number of particles required (i.e., ≥20≥20 times the original system). We show that our methodology has potential applications modeling systems of high molecular weight molecules at large scales, such as diblock copolymer and DNA.

  6. Consistent model reduction of polymer chains in solution in dissipative particle dynamics: Model description

    Science.gov (United States)

    Moreno, Nicolas; Nunes, Suzana P.; Calo, Victor M.

    2015-11-01

    We introduce a framework for model reduction of polymer chain models for dissipative particle dynamics (DPD) simulations, where the properties governing the phase equilibria such as the characteristic size of the chain, compressibility, density, and temperature are preserved. The proposed methodology reduces the number of degrees of freedom required in traditional DPD representations to model equilibrium properties of systems with complex molecules (e.g., linear polymers). Based on geometrical considerations we explicitly account for the correlation between beads in fine-grained DPD models and consistently represent the effect of these correlations in a reduced model, in a practical and simple fashion via power laws and the consistent scaling of the simulation parameters. In order to satisfy the geometrical constraints in the reduced model we introduce bond-angle potentials that account for the changes in the chain free energy after the model reduction. Following this coarse-graining process we represent high molecular weight DPD chains (i.e.,  ≥ 200 beads per chain) with a significant reduction in the number of particles required (i.e.,  ≥ 20 times the original system). We show that our methodology has potential applications modeling systems of high molecular weight molecules at large scales, such as diblock copolymer and DNA.

  7. [Latex allergy and cross-reactions: a new threat?].

    Science.gov (United States)

    Stevens, W

    2000-01-01

    Allergy to latex proteins has become an important problem, especially in the medical profession, but also in people who have regularly contact with latex products. The responsible antigens are proteins, which are present in the natural rubber latex (NRL), extracted from Hevea brasiliensis. These proteins are important in the synthesis of rubber and in the defence of the plant against external noxes (pathogenesis related proteins). Life threathening reactions occur more frequently in the operating theatre. Sensitisation can occur via different routes (aerogen, skin, parenteral, ...) but aerogenic sensitisation seems to be very important. Starch particles are important vectors of the antigens. Diagnosis is made via history, confirmed by demonstration of specific IgE via skin test (in vivo) or via an in vitro method (e.g. CAP, ELISA). Immunological cross reactions are very frequent with other plant or fruit allergens but cross allergy is less frequent (sensitivity and specificity of the in vitro test varies considerably depending on the nature of the fruit or vegetable investigated). There is also a cross reactivity with Ficus. Prevention with latex allergens becomes primordial in hospital settings. The industry is aware of the problem and produces more and more synthetic latex products. PMID:10818822

  8. Arrested chain growth during magnetic directed particle assembly in yield stress matrix fluids.

    Science.gov (United States)

    Rich, Jason P; McKinley, Gareth H; Doyle, Patrick S

    2012-02-28

    The process of assembling particles into organized functional structures is influenced by the rheological properties of the matrix fluid in which the assembly takes place. Therefore, tuning these properties represents a viable and as yet unexplored approach for controlling particle assembly. In this Letter, we examine the effect of the matrix fluid yield stress on the directed assembly of polarizable particles into linear chains under a uniform external magnetic field. Using particle-level simulations with a simple yield stress model, we find that chain growth follows the same trajectory as in Newtonian matrix fluids up to a critical time that depends on the balance between the yield stress and the strength of magnetic interactions between particles; subsequently, the system undergoes structural arrest. Appropriate dimensionless groups for characterizing the arresting behavior are determined and relationships between these groups and the resulting structural properties are presented. Since field-induced structures can be indefinitely stabilized by the matrix fluid yield stress and "frozen" into place as desired, this approach may facilitate the assembly of more complex and sophisticated structures. PMID:22335399

  9. Tests of the photon detection chain for the LHCb RICH Upgrade in a particle beam

    CERN Document Server

    Cardinale, Roberta

    2016-01-01

    The LHCb detector will be upgraded to use the available luminosity at the LHC in Run III and extend its potential for discovery. The Ring Imaging Cherenkov (RICH) detectors are one of the key components of the LHCb detector for particle identification. In this paper, we describe the setup and the results of the first tests in a particle beam carried out to assess prototypes of the upgraded optoelectronic chain from the Multi-Anode PMT photosensor to the readout and data acquisition system.

  10. Flocculation of fine fluorite particles with Corynebacterium xerosis and commercial long chain polymers

    Directory of Open Access Journals (Sweden)

    Rigo Lisandra N.

    2002-01-01

    Full Text Available This work aimed to study, comparatively, the flocculation of fluorite particles with Corynebacterium xerosis cells and three commercial long chain polymers. Best flocculation results were obtained with cells of C. xerosis and with an anionic polyacrylamide. Both were effective in solids removal and water clarification, although flocculation with C. xerosis cells requires a higher dosage of reagent per mass unit of processed ore.

  11. Involvement of Ethylene in the Latex Metabolism and Tapping Panel Dryness of Hevea brasiliensis

    Directory of Open Access Journals (Sweden)

    Riza-Arief Putranto

    2015-08-01

    Full Text Available Ethephon, an ethylene releaser, is used to stimulate latex production in Hevea brasiliensis. Ethylene induces many functions in latex cells including the production of reactive oxygen species (ROS. The accumulation of ROS is responsible for the coagulation of rubber particles in latex cells, resulting in the partial or complete stoppage of latex flow. This study set out to assess biochemical and histological changes as well as changes in gene expression in latex and phloem tissues from trees grown under various harvesting systems. The Tapping Panel Dryness (TPD susceptibility of Hevea clones was found to be related to some biochemical parameters, such as low sucrose and high inorganic phosphorus contents. A high tapping frequency and ethephon stimulation induced early TPD occurrence in a high latex metabolism clone and late occurrence in a low latex metabolism clone. TPD-affected trees had smaller number of laticifer vessels compared to healthy trees, suggesting a modification of cambial activity. The differential transcript abundance was observed for twenty-seven candidate genes related to TPD occurrence in latex and phloem tissues for ROS-scavenging, ethylene biosynthesis and signalling genes. The predicted function for some Ethylene Response Factor genes suggested that these candidate genes should play an important role in regulating susceptibility to TPD.

  12. Chemical synthesis of magnetic Fe-B and Fe-Co-B particles and chains

    International Nuclear Information System (INIS)

    With an objective to develop magnetic materials with high saturation magnetization for the Magnetically Assisted Chemical Separation (MACS) process the chemical synthesis of Fe-B and Fe-Co-B alloys by reducing iron and cobalt chloride solutions with potassium borohydride has been investigated systematically. The influence of the concentration of the reactants, applied magnetic field, reaction atmosphere, and method of mixing the reactants on the microstructure, particle size, composition and magnetic properties has been studied. Both M-B (M = Fe and Co) particles and elongated chains composed of nanometer size M-B particles have been obtained depending on the reaction conditions. The Fe-B samples exhibit saturation magnetization of MS of 120--190 emu/g, remanent magnetization Mr of 10--22 emu/g, and coercive field Hc of 400--900 Oe. A high MS value of 190 emu/g, which is close to the theoretical value of 218 emu/g for pure Fe, has been achieved particularly for samples with well-defined chain structures. Increasing the Co content in the Fe-Co-B alloys increases the boron content and thereby decreases the crystallinity and MS values although marginal increase in Hc (1,250 Oe) and Mr (36 emu/g) values could be made in some Fe-Co-B compositions. The chain structure with high MS may be attractive for other magnetic separation processes as well

  13. Effects of particle size and chain length on flotation of quaternary ammonium salts onto kaolinite

    Science.gov (United States)

    Longhua, Xu; Yuehua, Hu; Faqin, Dong; Hao, Jiang; Houqin, Wu; Zhen, Wang; Ruohua, Liu

    2015-06-01

    Effects of particle size and chain length on flotation of quaternary ammonium salts (QAS) onto kaolinite have been investigated by flotation tests. Dodecyltrimethylammonium chloride (DTAC) and cetyltrimethylammonium chloride (CTAC) were used as collectors for kaolinite in different particle size fractions (0.075 ~ 0.01 mm, 0.045 ~ 0.075 mm, 0 ~ 0.045 mm). The anomalous flotation behavior of kaolinite have been further explained based on crystal structure considerations by adsorption tests and molecular dynamics (MD) simulation. The results show that the flotation recovery of kaolinite in all different particle size fractions decreases with an increase in pH. As the concentration of collectors increases, the flotation recovery increases. The longer the carbon chain of QAS is, the higher the recoveries of coarse kaolinite (0.075 ~ 0.01 mm and 0.045 ~ 0.075 mm) are. But the flotation recovery of the finest kaolinite (0 ~ 0.045 mm) decreases with chain lengths of QAS collectors increasing, which is consistent with the flotation results of unscreened kaolinite (0 ~ 0.075 mm). It is explained by the froth stability related to the residual concentration of QAS collector in mineral pulp. In lower residual concentration, the froth stability becomes worse. Within the range of flotation collector concentration, it's easy of CTAC to be completely adsorbed by kaolinite in the particle size fraction (0-0.045 mm), which led to lower flotation recovery. Moreover, it is interesting that the coarser particle size of kaolinite is, the higher flotation recovery is. The anomalous flotation behavior of kaolinite is rationalized based on crystal structure considerations. The results of MD simulations show that the (001) kaolinite surface has the strongest interaction with DTAC, compared with the (00 1) face, (010) and (110) edges. On the other hand, when particle size of kaolinite is altered, the number of basal planes and edge planes is changed. It is observed that the finer kaolinite

  14. Hydrophilic magnetic latex for nucleic acid extraction, purification and concentration

    International Nuclear Information System (INIS)

    Core-shell magnetic latex particles bearing poly(N-isopropylacrylamide) in the shell were prepared by encapsulation of magnetic core using a precipitation polymerization process. The cationic character of the particles' surface is favorable for nucleic acid adsorption-desorption by controlling the pH and salinity of the medium. The concentration process of nucleic acids was presented and proven using DNA as a model

  15. Antioxidant and sensitizer effect on the stability of natural rubber latex vulcanized by gamma rays

    International Nuclear Information System (INIS)

    The natural rubber latex was vulcanized by gamma rays and electrons beam, in the presence and absence of sensitizer at room temperature. The sensitizers were the following; n-butyl acrylate (n-BA) / t-butyl hydroperoxide (t-B H) / KOH, C Cl4 / potassium laurate and n-BA / KOH. The studied antioxidants, Irganox 1520, Vulcanox SP and Vulcanox BKF, were added to the latex after irradiation. Among the studied antioxidants in function of tensile strength (TS) after the aging of rubber plates, the Irganox was the best efficient on the gamma vulcanization in the presence of n-BA/t-B H/KOH, because only 0,20 p hr is enough to obtain the greatest increase of TS, that was 34%, 12 MPa to 16 MPa. The formulating method of latex with the sensitizer constituted the 3,0 p hr of n-BA/ 0,1 p hr of t-B H and 0,2 p hr of KOH, was evaluated respecting the TS of rubber plates. The electrons beam vulcanization produces the greatest reversible perturbance in the colloidal stability of latex after irradiation caused by radiolytic species absorption that promotes the increase of particle size. The antioxidant also contributes to reversible destabilization of gamma irradiated latex, because it is also adsorbed by particles surface. The relation between the latex viscosity and the TS of respective rubber plates is reverse, showing the latex stability affects the quality of rubber goods. (author)

  16. How does the scaling for the polymer chain in the dissipative particle dynamics hold?

    Directory of Open Access Journals (Sweden)

    J.M.Ilnytskyi

    2007-12-01

    Full Text Available We performed a series of simulations for a linear polymer chain in a solvent using dissipative particle dynamics to check the scaling relations for the end-to-end distance, radius of gyration and hydrodynamic radius in three dimensions. The polymer chains of up to 80 beads in explicit solvent of various quality are studied. To extract the scaling exponent ν, the data are analyzed using linear fits, correction-to-scaling forms and analytical fits to the histograms of radius of gyration distribution. For certain combinations of the polymer characteristics and solvent quality, the correction-to-scaling terms are found to be essential while for the others these are negligibly small. In each particular case the final value for the exponent ν was chosen according to the best least-squares fit. The values of ν obtained in this way are found within the interval ν=0.55/0.61 but are concentrated mostly around 0.59, which is very close to the best known theoretical result ν=0.588. The existence of this interval is attributed both to the peculiarities of the method and to the moderate chain lengths being simulated. Within this shortcoming, the polymer chain in this kind of modeling is found to satisfy the scaling relations for all three radii being considered.

  17. Latex Allergy - A Case Report

    Directory of Open Access Journals (Sweden)

    Dr. Athma Prasanna

    2005-10-01

    Full Text Available The usage of rubber and its products are not uncommon in various walks of life. A continuous exposure or contact may sensitize the human body, causing reactions from mild to fatal. Despite the availability of the literature, medical personnel are still unaware of the implications of the use of latex materials.

  18. Parametric characterizations in superparamagnetic latex

    Indian Academy of Sciences (India)

    Seda Beyaz; Hakan Kockar; Taner Tanrisever

    2014-05-01

    The effect of synthesis parameters on the production of superparamagnetic latex, which are magnetite nanoparticles covered with a poly(methyl methacrylate) layer, were studied. The synthesis method was based on the developed route of emulsifier-free emulsion polymerization. Under this study, effects of the monomer and initiator concentrations, the amount of magnetic sol, the stirring rate and the adding rate of the magnetic sol on the properties of synthesized latexes were investigated. The characterizations were performed by a high resolution transmission electron microscopy, a dynamic light scattering, a vibrating sample magnetometer and a gel permeation chromatography. The results showed that the monomer concentration was found to be the most effective parameter on latex stability. As the initiator amount and the stirring rate increased, saturation magnetization and average molecular weight decreased due to the reactions occurring between surfaces of magnetite nanoparticles and initiator fragments. On increasing amount of magnetic sol, the saturation magnetization and polymer molecular weight increased but the size of nanospheres was unchanged because of the ions in magnetic sol. It was seen that the desired size and magnetic properties of the latex could be obtained since the parameters were found to have substantial impact on their properties.

  19. String hypothesis for gl(n|m) spin chains: a particle/hole democracy

    CERN Document Server

    Volin, Dmytro

    2010-01-01

    This paper is devoted to integrable gl(n|m) spin chains which allow for formulation of the string hypothesis. Considering the thermodynamic limit of such spin chains, we derive linear functional equations that symmetricaly treat holes and particles. The functional equations naturally organize different types of excitations into a pattern equivalent to the one of Y-system, and, not surprisingly, the Y-system can be easily derived from the functional equations. The Y-system is known to contain most of the information about the symmetry of the model, therefore we map the symmetry knowledge directly to the description of string excitations. Our analysis is applicable for highest weight representations which for some choice of the Kac-Dynkin diagram have only one nonzero Dynkin label. This generalizes known results for the AdS/CFT spectral problem and for the Hubbard model.

  20. Restrictions in Model Reduction for Polymer Chain Models in Dissipative Particle Dynamics

    KAUST Repository

    Moreno, Nicolas

    2014-06-06

    We model high molecular weight homopolymers in semidilute concentration via Dissipative Particle Dynamics (DPD). We show that in model reduction methodologies for polymers it is not enough to preserve system properties (i.e., density ρ, pressure p, temperature T, radial distribution function g(r)) but preserving also the characteristic shape and length scale of the polymer chain model is necessary. In this work we apply a DPD-model-reduction methodology for linear polymers recently proposed; and demonstrate why the applicability of this methodology is limited upto certain maximum polymer length, and not suitable for solvent coarse graining.

  1. Detection of Rabies Virus Antigen in Dog Saliva Using a Latex Agglutination Test

    OpenAIRE

    Kasempimolporn, S.; Saengseesom, W.; Lumlertdacha, B.; Sitprija, V.

    2000-01-01

    Dog bites are responsible for more than 90% of human rabies deaths in Asia. We developed a simple and inexpensive test based on latex agglutination (LA) for rabies virus antigen detection in dog saliva. Rabies virus antigen could be detected by agglutination on a glass slide using latex particles coated with gamma globulin. By evaluation of paired saliva-brain specimens from 238 dogs, the LA test using saliva was 99% specific and 95% sensitive compared to the fluorescent antibody test (FAT) o...

  2. Detection of Rocky Mountain spotted fever antibodies by a latex agglutination test.

    OpenAIRE

    Hechemy, K E; Anacker, R L; Philip, R N; Kleeman, K T; MacCormack, J. N.; Sasowski, S J; Michaelson, E E

    1980-01-01

    A latex test for immunodiagnosis of Rocky Mountain spotted fever, using erythrocyte-sensitizing substance from Rickettsia rickettsii adsorbed to latex particles, has been developed. The test was evaluated with a total of 123 single and 118 paired human sera submitted for Rocky Mount spotted fever testing. This test is simple, sensitive, and specific. Its efficiency, relative to the reference microimmunofluorescence test, was 95.1% for single sera and approached 100% for paired sera.

  3. HIGH SOLIDS-CONTENT NANOSIZE POLYMER LATEXES MADE BY A MODIFIED EMULSION COPOLYMERIZATION

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yuying; GUO Tianying; HAO Guangjie; SONG Maodao; Zhang Banghua

    2003-01-01

    Polymer nanoparticles were prepared in the methyl methacrylate (MMA)/buty lmethacrylate (BA) emulsion copolymerization process by a modified microemulsion copolymerization method. 2-Hydroxyethyl methacrylate(HEMA), acrylate (AA) and methyl acrylate (MAA) were used as reactive cosurfactants. With this process high polymer: surfactant weight ratios (40:1 or greater),relatively concentrated (~30wt. %) latexes and small (~60nm) particle diameters were obtained.Properties of the latexes were characterized by TEM, DSC, dynamic light scattering, and IR spectroscopy.

  4. Anomalous dynamical scaling in anharmonic chains and plasma models with multi-particle collisions

    CERN Document Server

    Di Cintio, Pierfrancesco; Bufferand, Hugo; Ciraolo, Guido; Lepri, Stefano; Straka, Mika J

    2015-01-01

    We study the anomalous dynamical scaling of equilibrium correlations in one dimensional systems. Two different models are compared: the Fermi-Pasta-Ulam chain with cubic and quartic nonlinearity and a gas of point particles interacting stochastically through the Multi-Particle Collision dynamics. For both models -that admit three conservation laws- by means of detailed numerical simulations we verify the predictions of Nonlinear Fluctuating Hydrodynamics for the structure factors of density and energy fluctuations at equilibrium. Despite of this, violations of the expected scaling in the currents correlation are found in some regimes, hindering the observation of the asymptotic scaling predicted by the theory. In the case of the gas model this crossover is clearly demonstrated upon changing the coupling constant.

  5. The physical and degradation properties of starch-graft-acrylonitrile/carboxylated nitrile butadiene rubber latex films.

    Science.gov (United States)

    Misman, M A; Azura, A R; Hamid, Z A A

    2015-09-01

    Starch-graft-acrylonitrile (ANS) is compounded with carboxylated nitrile butadiene rubber (XNBR) latex. The control XNBR and the ANS/XNBR latex films were prepared through a coagulant dipping process. The films were subjected to ageing and soil burial procedures. For the biodegradation experiment, the surface of the film was assessed after the 2nd, 4th and 8th week of soil burial. The ANS, XNBR, and ANS/XNBR colloidal stability were determined with a Malvern Zetasizer. For the dipped latex films, the mechanical, morphological and thermal properties were analyzed. The addition of ANS into the XNBR latex increased the stability of the colloidal dispersions, decreased the latex film tensile strength, but increased the elongation at break due to the bipolar interaction of the ANS and XNBR particles. The ANS/XNBR latex films aged faster than the control films while the morphological analysis showed the existence of a starch crystal region and the formation of microbial colonies on the surfaces of the films. Based on the TGA-DTA curves, a higher ΔT was observed for the ANS/XNBR latex films signifying high thermal energy needed for the film to thermally degrade. PMID:26005134

  6. Study on the thermal resistance in secondary particles chain of silica aerogel by molecular dynamics simulation

    International Nuclear Information System (INIS)

    In this article, molecular dynamics simulation was performed to study the heat transport in secondary particles chain of silica aerogel. The two adjacent particles as the basic heat transport unit were modelled to characterize the heat transfer through the calculation of thermal resistance and vibrational density of states (VDOS). The total thermal resistance of two contact particles was predicted by non-equilibrium molecular dynamics simulations (NEMD). The defects were formed by deleting atoms in the system randomly first and performing heating and quenching process afterwards to achieve the DLCA (diffusive limited cluster-cluster aggregation) process. This kind of treatment showed a very reasonable prediction of thermal conductivity for the silica aerogels compared with the experimental values. The heat transport was great suppressed as the contact length increased or defect concentration increased. The constrain effect of heat transport was much significant when contact length fraction was in the small range (0.5). Also, as the contact length increased, the role of joint thermal resistance played in the constraint of heat transport was increasing. However, the defect concentration did not affect the share of joint thermal resistance as the contact length did. VDOS of the system was calculated by numerical method to characterize the heat transport from atomic vibration view. The smaller contact length and greater defect concentration primarily affected the longitudinal acoustic modes, which ultimately influenced the heat transport between the adjacent particles

  7. Study on the thermal resistance in secondary particles chain of silica aerogel by molecular dynamics simulation

    Energy Technology Data Exchange (ETDEWEB)

    Liu, M. [Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing100190 (China); Department of Physics, University of Chinese Academy of Sciences, Beijing 100049 (China); Qiu, L., E-mail: qiulin111@sina.com, E-mail: jzzhengxinghua@163.com; Zheng, X. H., E-mail: qiulin111@sina.com, E-mail: jzzhengxinghua@163.com; Zhu, J.; Tang, D. W. [Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing100190 (China)

    2014-09-07

    In this article, molecular dynamics simulation was performed to study the heat transport in secondary particles chain of silica aerogel. The two adjacent particles as the basic heat transport unit were modelled to characterize the heat transfer through the calculation of thermal resistance and vibrational density of states (VDOS). The total thermal resistance of two contact particles was predicted by non-equilibrium molecular dynamics simulations (NEMD). The defects were formed by deleting atoms in the system randomly first and performing heating and quenching process afterwards to achieve the DLCA (diffusive limited cluster-cluster aggregation) process. This kind of treatment showed a very reasonable prediction of thermal conductivity for the silica aerogels compared with the experimental values. The heat transport was great suppressed as the contact length increased or defect concentration increased. The constrain effect of heat transport was much significant when contact length fraction was in the small range (<0.5) or the defect concentration is in the high range (>0.5). Also, as the contact length increased, the role of joint thermal resistance played in the constraint of heat transport was increasing. However, the defect concentration did not affect the share of joint thermal resistance as the contact length did. VDOS of the system was calculated by numerical method to characterize the heat transport from atomic vibration view. The smaller contact length and greater defect concentration primarily affected the longitudinal acoustic modes, which ultimately influenced the heat transport between the adjacent particles.

  8. Synthesis of P(St-BA-MAA-SPAA) nano-latex and its application in high anti-corrisive coating

    Institute of Scientific and Technical Information of China (English)

    LIU Hai-feng; SHENG Ming-shuang; PAN Zhao-ji; QIU Da-jian; GUO Zhi-hua; GAN Fu-xing

    2008-01-01

    A novel zinc-rich pigment based on P(St-BA-MAA-SPAA) nano-latex was obtained, which is suitable for the use in hot alkali liquid medium. The nano-latex was synthesized by active emulsifier latex polymerization method with monomers of styrene(St), butylaerylate (BA), methylacrylic acid(MAA) in the presence of active emulsifier 3-sulfopropylaerylate(SPAA). The synthesis condition and properties of the latex were investigated. And the anti-corrosive property of the resultant zinc-rich coating was studied. The results show that the nano-latex is self-stabilized and has a narrow particle diameter distribution, the average diameter of the latex particles is 71 nm. Zinc powders can be evenly dispersed in the nano-latex, which indicates that the P(St-BA-MAA-SPAA)nano latex can be used as the binder of zinc-rich coating. The resultant zinc-rich coating is able to resist the invasion of hot alkali solution(the temperature is 95 ℃ and the pH value is 14) for 480 h and the exposure time in salt spray is 1 200 h. Moreover, the coating shows good thermal conductivity and static electricity properties, its thermal conductivity and electric resistivity are 21-37 W/(m·K) and 6.7×105-3.5×106 Ω.cm, respectively

  9. Application of radiation vulcanized natural rubber latex in Indonesia

    International Nuclear Information System (INIS)

    The center has carried out R and D of Radiation Vulcanization Natural Rubber Latex (RVNRL) technology and introduced it to the industries since the inauguration and operation of the latex pilot plant in 1983. After years of experiences and the environmental consideration, n-butylacrylate (n-BA) has replaced CCI, as the sensitizer. Until now the introduction program shows that radiation vulcanized latex is more suitable for home industries than large industries. The obstacle of the program is the marketing of the dipped products. In spite of these problems, the introduction of this technology to the people in some undeveloped area of Java has supported the national program to improve their living standard. The problems of nitrosamine and protein allergic have turn up RVNRL to be the substitute of sulfur vulcanized latex in the future. The cooperation with a national condom manufacturer (PT Mitra Banjaran) has applied RVNRL for condom production in the large scale. Soft condoms with less probability of pinhole are obtained, but the technical problem is stickiness after pilling. Supply to a baby teat and a rubber thread manufacturer offers great advantages by not using any chemicals. In spite of the advantages, the problem of latex viscosity for dipping and the low modulus of elasticity of the threads arise. Through those input CAIR-BATAN is conducting the research and development in improving the crosslinking among the rubber particles that are supposed to be the reason of the stickiness and low modulus of elasticity. This effort is expected to be able to broaden the application of RVNRL, and it will be achieved only by the involvement of rubber chemist, rubber technologist, and radiation chemist

  10. Spherical core-shell magnetic particles constructed by main-chain palladium N-heterocyclic carbenes

    Science.gov (United States)

    Zhao, Huaixia; Li, Liuyi; Wang, Jinyun; Wang, Ruihu

    2015-02-01

    The encapsulation of the functional species on magnetic core is a facile approach for the synthesis of core-shell magnetic materials, and surface encapsulating matrices play crucial roles in regulating their properties and applications. In this study, two core-shell palladium N-heterocyclic carbene (NHC) particles (Fe3O4@PNP1 and Fe3O4@PNP2) were prepared by a one-pot reaction of semi-rigid tripodal imidazolium salts and palladium acetate in the presence of magnetite nanoparticles. The magnetite nanoparticles are encapsulated inside the main-chain palladium, which act as cores. The conjugated effects of triphenyltriazine and triphenylbenzene in the imidazolium salts have important influence on their physical properties and catalytic performances. Fe3O4@PNP2 shows better recyclability than Fe3O4@PNP1. Unexpectedly, Pd(ii) is well maintained after six consecutive catalytic runs in Fe3O4@PNP2, and Pd(0) and Pd(ii) coexist in Fe3O4@PNP1 under the same conditions; moreover, the morphologies of these spherical core-shell particles show no significant variation after six consecutive catalytic runs.The encapsulation of the functional species on magnetic core is a facile approach for the synthesis of core-shell magnetic materials, and surface encapsulating matrices play crucial roles in regulating their properties and applications. In this study, two core-shell palladium N-heterocyclic carbene (NHC) particles (Fe3O4@PNP1 and Fe3O4@PNP2) were prepared by a one-pot reaction of semi-rigid tripodal imidazolium salts and palladium acetate in the presence of magnetite nanoparticles. The magnetite nanoparticles are encapsulated inside the main-chain palladium, which act as cores. The conjugated effects of triphenyltriazine and triphenylbenzene in the imidazolium salts have important influence on their physical properties and catalytic performances. Fe3O4@PNP2 shows better recyclability than Fe3O4@PNP1. Unexpectedly, Pd(ii) is well maintained after six consecutive catalytic runs in

  11. Fitting complex population models by combining particle filters with Markov chain Monte Carlo.

    Science.gov (United States)

    Knape, Jonas; de Valpine, Perry

    2012-02-01

    We show how a recent framework combining Markov chain Monte Carlo (MCMC) with particle filters (PFMCMC) may be used to estimate population state-space models. With the purpose of utilizing the strengths of each method, PFMCMC explores hidden states by particle filters, while process and observation parameters are estimated using an MCMC algorithm. PFMCMC is exemplified by analyzing time series data on a red kangaroo (Macropus rufus) population in New South Wales, Australia, using MCMC over model parameters based on an adaptive Metropolis-Hastings algorithm. We fit three population models to these data; a density-dependent logistic diffusion model with environmental variance, an unregulated stochastic exponential growth model, and a random-walk model. Bayes factors and posterior model probabilities show that there is little support for density dependence and that the random-walk model is the most parsimonious model. The particle filter Metropolis-Hastings algorithm is a brute-force method that may be used to fit a range of complex population models. Implementation is straightforward and less involved than standard MCMC for many models, and marginal densities for model selection can be obtained with little additional effort. The cost is mainly computational, resulting in long running times that may be improved by parallelizing the algorithm. PMID:22624307

  12. Study of Vietnam latex for radiation vulcanization

    International Nuclear Information System (INIS)

    Radiation vulcanization of 6 different centrifuged latexes was studied. Sensitiser was n-BA of 5 phr and irradiation was carried out on gamma Co-60 source at 12 kGy, dose rate 3.4 kGy/h. Viscosity of latex and tensile strength of rubber films were measured. Result showed that the stability of LA type latex against the addition of n-B A was better than that of HA. Of 6 concentrated latexes studied, only two were suitable for radiation vulcanization process regarding tensile strength and stability

  13. Latex Allergy In Health Care Workers

    OpenAIRE

    Hayriye Sarıcaoğlu; Sevil Ovalı Toka; Sema İpek Algan

    2013-01-01

    Background and Design: We aimed to determine the frequency of latex allergy in our hospital and to to evaluate the clinical and demographical features of the cases.Materials and Methods: A detailed questionnaire was administered to healthcare workers by a physician. Skin prick test with latex and patch test with rubber chemicals and a piece of latex glove were performed for all healthcare workers. Latex-specific IgE was measured in serum.Results: The study sample consisted of 36 nurses, 14 do...

  14. Latex allergy: a model for therapy.

    Science.gov (United States)

    Rolland, J M; O'Hehir, R E

    2008-06-01

    Allergy to natural rubber latex products emerged as an important clinical condition following an increase in the use of latex gloves for barrier protection in the early 1980s. In addition to latex glove users, other high-risk groups with different latex exposure include spina bifida patients and others with multiple surgical procedures. Subjects with fruit and vegetable allergy are also at risk due to cross-reactive allergens. Following the significant advances in the identification and characterization of common aeroallergens, latex allergy was well placed to become an excellent model of therapy. Awareness of latex allergy and modes of sensitization enabled epidemiological studies to inform allergen avoidance initiatives, substantially reducing inadvertent exposure in major hospitals in Western countries. Spina bifida is often identified in utero or soon after birth, allowing vigorous latex allergen avoidance with enhanced efficacy of primary prevention. However, changing demographics of latex allergy and technological revolution in countries such as China and India are predicted to unleash a second wave of latex allergy reemphasizing the incentive for improved manufacturing procedures for latex products. The desirable high tensile strength and elasticity of natural rubber latex have made the commercial identification of good alternatives very difficult but this would also be attractive for primary prevention. In addition, an effective specific immunotherapy regimen would be valuable for selected high-risk atopic individuals. Current subcutaneous and sublingual immunotherapy schedules have been tested for treatment of latex allergy with evidence of efficacy but the risks of adverse events are high. For such potent allergens as latex, hypoallergenic but T cell-reactive preparations are required for clinical use. Identification of allergenic components of latex products, with generation of monoclonal antibodies and recombinant allergens, allowed sequence

  15. Interaction between surfactants and colloidal latexes in nonpolar solvents studied using contrast-variation small-Angle neutron scattering

    OpenAIRE

    Smith, Gregory; Alexander, Shirin; Brown, Paul; Gillespie, David A J; Grillo, Isabelle; Heenan, Richard K.; James, Craig; Kemp, Roger D; Rogers, Sarah E.; Eastoe, Julian

    2014-01-01

    The interaction between deuterium-labeled Aerosol OT surfactant (AOT-d 34) and sterically stabilized poly(methyl methacrylate) (PMMA) latex particles dispersed in nonpolar solvents has been studied using contrast-variation small-Angle neutron scattering (CV-SANS). The electrophoretic mobilities (μ) of the latexes have been measured by phase-Analysis light scattering, indicating that μ is negative. Two analogues of the stabilizers for the particles have been studied as free polymers in the abs...

  16. Optimization of Setup Frequency for TOC Supply Chain Replenishment Systems Based on Pareto Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Xiao-Yun Jiang

    2013-12-01

    Full Text Available The theory of constraints (TOC supply chain replenishment system (TOC-SCRS is an effective solution for coping with conflicts during the management of supply chain inventories. When it is deployed in a plant or a central warehouse with capacity constraints, TOC-SCRS encounters a problem comprised of 2 parts: first, how to establish a sound setup frequency (SF that can meet production needs and prevent losses from stock-outs, meaning a SF that allows the plant to make full use of its existing capacity to achieve maximal effective output. Second, it must determine how to establish a sound SF that can help the plant minimize its inventory and cut costs to the greatest possible extent. To resolve the problem, a SF optimization model for TOC-SCRS with capacity constraints is constructed and is then used in combination with Pareto particle swarm optimization (PSO to obtain SF optimization schemes in this paper. An illustrative example is conducted to verify the feasibility and effectiveness of the proposed approach.

  17. Latex Allergy In Health Care Workers

    Directory of Open Access Journals (Sweden)

    Hayriye Sarıcaoğlu

    2013-05-01

    Full Text Available Background and Design: We aimed to determine the frequency of latex allergy in our hospital and to to evaluate the clinical and demographical features of the cases.Materials and Methods: A detailed questionnaire was administered to healthcare workers by a physician. Skin prick test with latex and patch test with rubber chemicals and a piece of latex glove were performed for all healthcare workers. Latex-specific IgE was measured in serum.Results: The study sample consisted of 36 nurses, 14 doctors, and 50 healthcare workers. While 46 subjects had symptoms, 54 subjects had no symptoms. The relationship of clinical disease with working duration, exposure duration (hour/day, history of atopy, and drug/food allergies was statistically significant. Five nurses and 1 healthcare worker had positive skin prick test. Two of them had positive latex-specific IgE. Positive skin prick test statistically significantly correlated with occupation, working duration, exposure duration (hour/day and positive latex-specific IgE. Two nurses and 2 healthcare workers had positive latex-specific IgE. Two of them had positive skin prick test. Positive latexspecific IgE statistically significantly correlated with working duration, exposure duration, and positive skin prick test. Patch test with a piece of latex glove was negative in all subjects. Three healthcare workers had positive patch test with thiuram-mix, one of them had also positive patch test with mercaptobenzothiazole.Discussion: One of the risk factors for latex allergy is occupations involving frequent exposure to latex products. Latex allergy should be taken into consideration if type I hypersensitivity reactions occur in occupational groups at risk for anaphylactic reaction.

  18. Effect of irradiation on the prevulcanized latex/low nitrosamines latex blends

    Energy Technology Data Exchange (ETDEWEB)

    Ibrahim, Pairu; Zin, Wan Manshol Wan [Malaysian Nuclear Agency, 43000 kajang, Selangor (Malaysia); Daik, Rusli [Faculty of Science and Technology, Universiti Kebangsaan Malaysia,43600 bangi, Selangor (Malaysia)

    2015-09-25

    Radiation Prevulcanized Natural Rubber Latex (RVNRL) was blended with Low Nitrosamines Latex (LNL) at different composition ratio. Methyl Metachrylate (MMA) was added for grafting onto the blended latex. Blended latex was subjected to gamma irradiation at various doses up to 8kGy. The mechanical properties and FTIR analysis were investigated as a function of the blended composition and irradiation dose. It was found that blending at specific ratio and gamma irradiation at specific dose led to significant improvement on the properties of the latex. The optimum mechanical properties was attained at a total blending ratio of 70% RVNRL and 30% of LNL.

  19. Thermodynamic limit of particle-hole form factors in the massless XXZ Heisenberg chain

    International Nuclear Information System (INIS)

    We study the thermodynamic limit of the particle-hole form factors of the XXZ Heisenberg chain in the massless regime. We show that, in this limit, such form factors decrease as an explicitly computed power-law in the system size. Moreover, the corresponding amplitudes can be obtained as a product of a ''smooth'' and a ''discrete'' part: the former depends continuously on the rapidities of the particles and holes, whereas the latter has an additional explicit dependence on the set of integer numbers that label each excited state in the associated logarithmic Bethe equations. We also show that special form factors corresponding to zero-energy excitations lying on the Fermi surface decrease as a power-law in the system size with the same critical exponents as in the longdistance asymptotic behavior of the related two-point correlation functions. The methods we develop in this article are rather general and can be applied to other massless integrable models associated to the six-vertex R-matrix and having determinant representations for their form factors. (orig.)

  20. Thermodynamic limit of particle-hole form factors in the massless XXZ Heisenberg chain

    Energy Technology Data Exchange (ETDEWEB)

    Kitanine, N. [Univ. de Bourgogne (France). IMB, UMR 5584 du CNRS; Kozlowski, K.K. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Maillet, J.M.; Terras, V. [ENS Lyon (France). UMR 5672 du CNRS, Lab. de Physique; Slavnov, N.A. [Steklov Mathematical Inst., Moscow (Russian Federation)

    2011-03-15

    We study the thermodynamic limit of the particle-hole form factors of the XXZ Heisenberg chain in the massless regime. We show that, in this limit, such form factors decrease as an explicitly computed power-law in the system size. Moreover, the corresponding amplitudes can be obtained as a product of a ''smooth'' and a ''discrete'' part: the former depends continuously on the rapidities of the particles and holes, whereas the latter has an additional explicit dependence on the set of integer numbers that label each excited state in the associated logarithmic Bethe equations. We also show that special form factors corresponding to zero-energy excitations lying on the Fermi surface decrease as a power-law in the system size with the same critical exponents as in the longdistance asymptotic behavior of the related two-point correlation functions. The methods we develop in this article are rather general and can be applied to other massless integrable models associated to the six-vertex R-matrix and having determinant representations for their form factors. (orig.)

  1. Cerium Biomagnification in a Terrestrial Food Chain: Influence of Particle Size and Growth Stage.

    Science.gov (United States)

    Majumdar, Sanghamitra; Trujillo-Reyes, Jesica; Hernandez-Viezcas, Jose A; White, Jason C; Peralta-Videa, Jose R; Gardea-Torresdey, Jorge L

    2016-07-01

    Mass-flow modeling of engineered nanomaterials (ENMs) indicates that a major fraction of released particles partition into soils and sediments. This has aggravated the risk of contaminating agricultural fields, potentially threatening associated food webs. To assess possible ENM trophic transfer, cerium accumulation from cerium oxide nanoparticles (nano-CeO2) and their bulk equivalent (bulk-CeO2) was investigated in producers and consumers from a terrestrial food chain. Kidney bean plants (Phaseolus vulgaris var. red hawk) grown in soil contaminated with 1000-2000 mg/kg nano-CeO2 or 1000 mg/kg bulk-CeO2 were presented to Mexican bean beetles (Epilachna varivestis), which were then consumed by spined soldier bugs (Podisus maculiventris). Cerium accumulation in plant and insects was independent of particle size. After 36 days of exposure to 1000 mg/kg nano- and bulk-CeO2, roots accumulated 26 and 19 μg/g Ce, respectively, and translocated 1.02 and 1.3 μg/g Ce, respectively, to shoots. The beetle larvae feeding on nano-CeO2 exposed leaves accumulated low levels of Ce since ∼98% of Ce was excreted in contrast to bulk-CeO2. However, in nano-CeO2 exposed adults, Ce in tissues was higher than Ce excreted. Additionally, Ce content in tissues was biomagnified by a factor of 5.3 from the plants to adult beetles and further to bugs. PMID:26690677

  2. Dissipative particle dynamics study of translational diffusion of rigid-chain rodlike polymer in nematic phase

    Science.gov (United States)

    Zhao, Tongyang; Wang, Xiaogong

    2013-09-01

    In this study, dissipative particle dynamics (DPD) method was employed to investigate the translational diffusion of rodlike polymer in its nematic phase. The polymer chain was modeled by a rigid rod composed of consecutive DPD particles and solvent was represented by independent DPD particles. To fully understand the translational motion of the rods in the anisotropic phase, four diffusion coefficients, D_{||}u, D_ bot u, D_{||}n, D_ bot n were obtained from the DPD simulation. By definition, D_{||}n and D_ bot n denote the diffusion coefficients parallel and perpendicular to the nematic director, while D_{||}u and D_ bot u denote the diffusion coefficients parallel and perpendicular to the long axis of a rigid rod u. In the simulation, the velocity auto-correlation functions were used to calculate the corresponding diffusion coefficients from the simulated velocity of the rods. Simulation results show that the variation of orientational order caused by concentration and temperature changes has substantial influences on D_{||}u and D_ bot u. In the nematic phase, the changes of concentration and temperature will result in a change of local environment of rods, which directly influence D_{||}u and D_ bot u. Both D_{||}n and D_ bot n can be represented as averages of D_{||}u and D_ bot u, and the weighted factors are functions of the orientational order parameter S2. The effect of concentration and temperature on D_{||}n and D_ bot n demonstrated by the DPD simulation can be rationally interpreted by considering their influences on D_{||}u, D_ bot u and the order parameter S2.

  3. Enhanced protein adsorption and patterning on nanostructured latex-coated paper.

    Science.gov (United States)

    Juvonen, Helka; Määttänen, Anni; Ihalainen, Petri; Viitala, Tapani; Sarfraz, Jawad; Peltonen, Jouko

    2014-06-01

    Specific interactions of extracellular matrix proteins with cells and their adhesion to the substrate are important for cell growth. A nanopatterned latex-coated paper substrate previously shown to be an excellent substrate for cell adhesion and 2D growth was studied for directed immobilization of proteins. The nanostructured latex surface was formed by short-wavelength IR irradiation of a two-component latex coating consisting of a hydrophilic film-forming styrene butadiene acrylonitrile copolymer and hydrophobic polystyrene particles. The hydrophobic regions of the IR-treated latex coating showed strong adhesion of bovine serum albumin (cell repelling protein), fibronectin (cell adhesive protein) and streptavidin. Opposite to the IR-treated surface, fibronectin and streptavidin had a poor affinity toward the untreated pristine latex coating. Detailed characterization of the physicochemical surface properties of the latex-coated substrates revealed that the observed differences in protein affinity were mainly due to the presence or absence of the protein repelling polar and charged surface groups. The protein adsorption was assisted by hydrophobic (dehydration) interactions. PMID:24802964

  4. EFFECT OF THE PHASE STRUCTURE EVOLUTION ON THE PROPERTIES OF FILMS FORMED FROM PBA/P(ST-CO-MMA)COMPOSITE LATEX

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A group of heterogeneous latexes poly(butyl acrylate)/poly(styrene-co-methyl methacrylate)(PBA/P(St-co-MMA))were prepared by a semi-continuous seeded emulsion polymerization process under monomer starved conditions.The glass transition temperature(Tg)and the mechanical properties of the film formed from the composite latex changed with the evolution of the particle morphology.A photon transmission method was used to monitor the phase structure evolution of films which were prepared from core-shell PBA/P(St-co-MMA)latex at room temperature and annealed at 383 K above Tg of the polymers.In addition,the changes of the surface of the film formed from the composite latex with time at 383 K were observed by AFM.The evidence illustrated that the film formed from the core-shell latex particles was metastable.The rearrangement of the phases could occur under proper conditions.

  5. Soliton-Like Pulses in Vertical Granular Chain Under Gravity: Particle-Like or Wave-Like?

    Institute of Scientific and Technical Information of China (English)

    XU Ai-Guo; HONG Jongbae

    2001-01-01

    We numerically study the propagation, reflection and collision of soliton-like pulses in the vertical granular chain under gravity. For the pure granular chain system, during the propagation and reflection processes at the fixed end, it behaves like a particle. When it is reflected at the free end, it behaves as neither particle-like nor wave-like.When the strengths of the two colliding soliton-like pulses are close, they collide just like particles. When their strengths are greatly different, they collide just like waves. For the soliton behavior in the collision process, from particle-like to wave-like, there is a critical value θC for the ratio θ of the strengths of the two initial pulses. For the two-layer granular chain, if the mass of the grains in the second layeris less than that in the first layer, the soliton-like pulse in the first layer usually excites about [1/m] soliton-like pulses in the second layer.``

  6. Latex allergy in dentistry: clinical cases report

    OpenAIRE

    Raggio, D.P.; Camargo, L.B.; Naspitz, G.M.C.C.; Politano, G.T.; Bonifacio, C.C.; Mendes, F.M.; Kierstman, F.

    2010-01-01

    Generally natural rubber latex (NRL) allergy is detected after some exposition to the material. As NRL is commonly found in different materials used daily in dental clinic, the allergy can be manifested in the pediatric dentistry clinic. The first clinical manifestation can be smooth but also severe, therefore it is important to know different manifestations and how to prevent them. Objective: Report two clinical cases of natural rubber latex allergy in children and to present the safety meas...

  7. IDENTIFICATION OF BACTERIA IN LATEX PAINTS

    Directory of Open Access Journals (Sweden)

    Rojas, J.

    2008-01-01

    Full Text Available The bacteria are prokaryote organisms with a high capacity to colonize many types of habits. This research was developed with the object to identify extremophiles bacteria presents in latex paint. The bacteria were cultivated in culture mediums TSA, Blood Agar, Mc Conkey and finally the biochemical proof API-NF® for bacteria's isolation and identification, respectively. Characterization showed bacterial profile of Pasteurella sp. Hypothesis that could be found extremophiles bacteria in latex paint were demonstrated.

  8. Evaluation of new streptococcal latex grouping kit.

    OpenAIRE

    Vicca, A F; Stansfield, R E; Masterton, R G

    1993-01-01

    AIMS: To evaluate a new streptococcal latex grouping kit (Shield Diagnostics Ltd) and compare it against an established latex agglutination method (Streptex; Wellcome Diagnostics). METHODS: Two hundred and forty seven strains of streptococci and enterococci were tested with each kit by one operator and according to the manufacturer's instructions. Strains failing to group or giving discordant results were identified to species level. RESULTS: Two discrepant grouping results were observed and ...

  9. Radiation curing of natural rubber latex

    International Nuclear Information System (INIS)

    Natural rubber latex (60% solids) was irradiated with Cobalt-60 gamma radiation upto 30 megarads. It was observed that 90% of the rubber was cross-linked at a cumulative dose of 2 megarads to 12 megarads. In case of the coagulated latex 74% of the rubber was cross-linked at the same dose. Thereafter the percentage cross-linked polymer decreased continuously upto 16 megarads in both the cases but increased again. (auth.)

  10. Improved levitation and trapping of particles by negative dielectrophoresis by the addition of amphoteric molecules

    International Nuclear Information System (INIS)

    Addition of amphoteres could be used to improve the levitation and trapping of particles by negative dielectrophoresis. Addition of amphoteric molecules to electromanipulation media increases not only the permittivity of the medium and its viscosity but also its density. To investigate the effect of addition of amphoteres on levitation and trapping by negative dielectrophoresis, the electrokinetic behaviour of latex beads and viable yeast cells (Saccharomyces cerevisiae) was investigated in concentrated solutions of the amphoteric molecules N-[2-hydroxyethyl] piperazine-N'-[2-ethanesulfonic acid] (HEPES) and ε-aminocaproic acid (EACA) using different frequencies and voltages of the applied electrical signal and microelectrodes of different sizes. When using interdigitated electrodes without castellations, latex beads levitated an average of 43% higher when 0.67 M EACA solutions were used and a 54% higher after adding 0.67 M HEPES compared with the levitation heights when no amphoteres were added. Under the same conditions, yeast levitated 78% and 86% higher, respectively. At low voltages and low HEPES/EACA concentrations, the latex particles accumulated in bands between or above the electrodes. However, at the highest voltages and HEPES/EACA concentrations used, the particles formed a network of pearl chains above the electrode arrays. When using electrodes of the interdigitated castellated type of characteristic size 30 μm, latex particles levitated 32% and 40% higher when 0.67 M EACA and HEPES solutions were used in comparison with when no amphoteres were added. At these concentrations, the flow rate needed to dislodge the latex particles from the traps formed by the electric field pattern between the castellations of the interdigitated castellated electrodes was increased by 46% compared with the flow rate needed to achieve this when no amphoteres were added

  11. Fluidization of extremely large and widely sized coal particles as well as its application in an advanced chain grate boiler

    Energy Technology Data Exchange (ETDEWEB)

    Liu, X.H.; Xu, G.W.; Gao, S.Q. [Chinese Academy of Sciences, Beijing (China)

    2008-12-02

    A pyrolysis combustion technology (PCT) was developed for high-efficiency and environment-friendly chain grate boilers (CGBs). The realization of the PCT in a CGB requires that extremely large and widely sized coal particles should be first pyrolyzed in a semi-fluidized state before being transported into the combustion chamber of the boiler. This article was devoted first to investigating the fluidization of 0-40 mm coal particles in order to demonstrate the technical feasibility of the PCT. In succession, through mixing 0-10 mm and 10-20 mm coal particles in different proportions, multiple pseudo binary mixtures were prepared and then fluidized to clarify the effect of particle size distribution. With raw steam coal used as the feedstock, the superficial gas velocity of about 2.0 m/s may be suitable for stable operation of the fluidized-bed pyrolyzer in the CGB with the PCT. In the fluidization of widely sized coal particles, approximately half of the coal mass is segregated into the bottom section of the bed, though about 15% of 10-20 turn large particles are broken into 0-10 mm small particles because of particle attrition. The experimental results illustrate that an advanced CGB with the PCT has a high adaptability for various coals with different size distributions.

  12. Latex allergy: an emerging problem in health care.

    Science.gov (United States)

    Kinnaird, S W; McClure, N; Wilham, S

    1995-10-01

    Allergy to latex has been increasing as the use of latex products has grown. The increase is disproportionately occurring in those people with myelodysplasias, those who have undergone multiple surgical procedures, and health care providers. Within those groups, the most susceptible to latex allergy are people with other allergies. Early identification of high-risk individuals and their avoidance of products containing latex can minimize the occurrence of this allergic response. Heightened awareness among health care providers is needed because latex is very common in hospitals and clinics. Inadvertent exposure places latex-sensitive individuals in danger of anaphylaxis. Nurses caring for infants and children are able to modify the environment of those at risk for latex allergy, reducing exposure to this potentially dangerous substance. Teaching families of children at risk will help them avoid latex in the home; many common household substances contain latex and are likely to trigger allergic responses. PMID:7565525

  13. Latex allergy among operating room personnel in Turkey.

    Science.gov (United States)

    Sener, O; Taskapan, O; Ozangüç, N

    2000-01-01

    This study was performed to evaluate the prevalence of latex allergy among health care workers in Turkey, as well as to compare the medical histories with the skin test results and investigate the risk factors. Using a 1/100 weight/volume commercial skin prick test (SPT), we investigated latex sensitization in 206 health care workers who regularly use latex products. One hundred atopic and 100 nonatopic patients without occupational latex exposure were also examined as control groups. Latex SPTs were positive in 10 health care workers (9.22%), whereas none of the control patients was found to have positive SPT to latex. Health care workers were divided into two groups based on the latex SPT results. There was no significant difference between the latex SPT-positive and -negative health care worker groups according to age, sex and total exposure time to latex. In the latex SPT positive group, daily exposure time and daily glove use were significantly higher (p rubber additives were positive in five out of 42 medical care workers. Two surgeons were found to have both type-I hypersensitivity to latex and type-IV hypersensitivity to rubber additives. Our results suggest that the frequency of latex allergy is higher in the atopic health care workers with a high exposure to latex, and that SPT is a sensitive, safe, cheap and easy method of testing the diagnosis of latex hypersensitivity. PMID:10780797

  14. Bimodal Latex Effect on Spin-Coated Thin Conductive Polymer-Single-Walled Carbon Nanotube Layers.

    Science.gov (United States)

    Moradi, Mohammad-Amin; Larrakoetxea Angoitia, Katalin; van Berkel, Stefan; Gnanasekaran, Karthikeyan; Friedrich, Heiner; Heuts, Johan P A; van der Schoot, Paul; van Herk, Alex M

    2015-11-10

    We synthesize two differently sized poly(methyl methacrylate-co-tert-butyl acrylate) latexes by emulsion polymerization and mix these with a sonicated single-walled carbon nanotube (SWCNT) dispersion, in order to prepare 3% SWCNT composite mixtures. We spin-coat these mixtures at various spin-speed rates and spin times over a glass substrate, producing a thin, transparent, solid, conductive layer. Keeping the amount of SWCNTs constant, we vary the weight fraction of our smaller 30-nm latex particles relative to the larger 70-nm-sized ones. We find a maximum in the electrical conductivity up to 370 S/m as a function of the weight fraction of smaller particles, depending on the overall solid content, the spin speed, and the spin time. This maximum occurs at 3-5% of the smaller latex particles. We also find a more than 2-fold increase in conductivity parallel to the radius of spin-coating than perpendicular to it. Atomic force microscopy points at the existence of lanes of latex particles in the spin-coated thin layer, while large-area transmission electron microscopy demonstrates that the SWCNTs are aligned over a grid fixed on the glass substrate during the spin-coating process. We extract the conductivity distribution on the surface of the thin film and translate this into the direction of the SWCNTs in it. PMID:26491888

  15. Synthesis of 3-D ordered macroporous silicate using the template formed from monodispersed polystyrene latex

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Based on the template formed from monodispersed polystyrene (PS) latex, a modified fast sol-gel process was employed to synthesize a three-dimensional ( 3-D ) ordered macroporous silica material after removing the template by calcination at high temperature. It was indicated that there existed highly ordered packed pores within the whole silica material by SEM morphology observation. It was also found that the pores were interconnected. The pore size could be controlled mainly by varying the particle size of the latex ranging from 101 to 102 nm. The formation process of the ordered pores was also preliminarily discussed.

  16. Radiation vulcanization of Philippine natural rubber latex

    International Nuclear Information System (INIS)

    The response of Philippine natural rubber latex to irradiation vulcanization and the stability of the irradiated natural rubber latex (INRL) upon storage and aging were investigated. Commercially available high ammonia (HA) concentrated latices obtained from various rubber plantations in Mindanao island were treated with 5 phr of n-butyl acrylate (nBA), and gamma-irradiated at the PNRI 60Co irradiation facility at a dose rate of 2.57 kGy/hr. Unirradiated cast latex films gave different green strengths which varied from 2-11 MPa. Cast films from INRL exhibited maximum tensile strengths were obtained from cast films with low Mg and high nitrogen contents. Thermal analysis using thermogravimetry (TG) revealed one major decomposition product at 374o-377oC. Its rate of decomposition decreased to a minimum at 15 kGy, then increased as radiation dose was increased. This trend correlated well with the tensile strength measurements. The stability of the INRL upon storage and aging is an essential parameter to the rubbe latex industry. For storage studies, INRL was stored for various periods of time. It was found that the pH and total solids content of the stored INRL did not change significantly after 12 months of storage; the MST values remained at above 1000 seconds, and the viscosity decreased with time. The cast films exhibited a decline in tensile strength, modulus300%, and crosslinking density upon storage. While there were observed changes in the physical properties of the INRL during the storage period, the data indicate that these properties were within values acceptable to the latex industry. Tests on the aging properties of INRL films were undertaken. It was shown that among the chemical antioxidants presently used by the latex industry, TNPP demonstrated the highest antioxidant property, followed by Antage DAHQ and Vulcanox BKF. Our data indicate that the natural rubber latex produced and processed in the Philippines is suited for radiation vulcanization

  17. Self-trapping and dynamics of a quasi-particle in a one-dimensional molecular chain under interaction with optical phonons

    International Nuclear Information System (INIS)

    The goal of this work is to establish the possibility of the self-trapping of a quasi-particle and to study the conditions of the self-trapping of quasi-particles in the chains with optical phonons by using the numerical modeling. We also study the dynamics of self-trapped soliton-like quasi-particles interacting with optical phonons

  18. Occupational asthma and rhinoconjunctivitis induced by natural rubber latex exposure.

    Science.gov (United States)

    Fish, James E

    2002-08-01

    A number of reports indicate that occupational exposure to natural rubber latex (NRL) in health care workers can elicit symptoms of rhinoconjunctivitis with or without asthma in selected individuals who are sensitized. The prevalence or risk of NRL-induced asthma in relation to rhinoconjunctivitis is small in comparison with other forms of occupational allergic respiratory disease. The lower risk of NRL-induced asthma appears to be related to poor penetration of the allergen into the lower respiratory tract because of the relatively large particle size of allergen-bearing cornstarch particles. Because of a lack of large prospective studies, little is know about the incidence and natural history of latex-induced respiratory disease. Because of heightened awareness of NRL allergy and changing patterns in glove manufacturing and glove use, it is likely that the occurrence of NRL-induced occupational respiratory disease will decline and its natural history will change. Nevertheless, because large number of individuals are exposed to NRL in various occupations, the incidence, prevalence, and natural history of NRL allergy merit further monitoring. PMID:12170247

  19. Latex industry and RVNRL development in Malaysia

    International Nuclear Information System (INIS)

    Malaysia, as the largest producer of NR, exported 72.9 % of World's total export of 455,000 tonnes NR latex in 1987. In 1988, it has also become one of the largest consumers of NR latex, consuming 61,063 tonnes and producing 1.34 billion pairs of gloves, 45.5 million units of catheters and other latex products. Malaysia began active research and development of RVNRL only recently and much of which is through its participation in the UNDP/RCA project on RVNRL. Commercialization of RVNRL in Malaysia is expected to begin once its technical and economic merits and market potential have been established and demonstrated. It is suggested that a world-wide marketing study be undertaken to access the actual market potential of RVNRL. Companies intending to commercialize RVNRL may collaborate with UTN and RRIM to develop the commercial process for RVNRL. (author)

  20. Triterpenoid biosynthesis in Euphorbia lathyris latex

    International Nuclear Information System (INIS)

    The structures of those tetracyclic triterpenols in Euphorbia lathyris latex which had not previously been known were elucidated. Many times dependent incubations were done, investigating the stability of the whole latex system and the re-suspended pellet systems. The effects of centrifugation on the biosynthesis were examined. The partitioning of the triterpenoid pool as a function of when the compounds were made was examined. A number of incubations were performed in the hopes of observing some interconversion of the individual triterpenols. The effect of several inhibitors on the biosynthesis of the triterpenoids was examined. The effects of the morpholine based fungicides, tridemorph and fenpropimorph were examined. The possibility that cycloartenol is made via lanosterol was investigated by synthesizing 4-R-4-3 H-mevalonic acid and incubating the latex with a mixture of this and 14C-mevalonic acid

  1. Understanding the Role of N-Methylolacrylamide (Nma) Distribution in Poly(Vinyl Acetate) Latex Adhesives

    OpenAIRE

    Brown, Nicole Robitaille

    2003-01-01

    This work addresses the distribution of N-methylolacrylamide (NMA) units in crosslinking poly(vinyl acetate) (PVAc) adhesives. In this case, distribution refers to the three potential locations of polymerized NMA units in a latex: the water-phase, the surface of polymer particles, and the core of the polymer particles. The objective is to identify the distribution of NMA in three latices and to determine whether NMA distribution correlates with durability related performance. NMA distribu...

  2. Phase-coexistence simulations of fluid mixtures by the Markov Chain Monte Carlo method using single-particle models

    International Nuclear Information System (INIS)

    We present a single-particle Lennard–Jones (L-J) model for CO2 and N2. Simplified L-J models for other small polyatomic molecules can be obtained following the methodology described herein. The phase-coexistence diagrams of single-component systems computed using the proposed single-particle models for CO2 and N2 agree well with experimental data over a wide range of temperatures. These diagrams are computed using the Markov Chain Monte Carlo method based on the Gibbs-NVT ensemble. This good agreement validates the proposed simplified models. That is, with properly selected parameters, the single-particle models have similar accuracy in predicting gas-phase properties as more complex, state-of-the-art molecular models. To further test these single-particle models, three binary mixtures of CH4, CO2 and N2 are studied using a Gibbs-NPT ensemble. These results are compared against experimental data over a wide range of pressures. The single-particle model has similar accuracy in the gas phase as traditional models although its deviation in the liquid phase is greater. Since the single-particle model reduces the particle number and avoids the time-consuming Ewald summation used to evaluate Coulomb interactions, the proposed model improves the computational efficiency significantly, particularly in the case of high liquid density where the acceptance rate of the particle-swap trial move increases. We compare, at constant temperature and pressure, the Gibbs-NPT and Gibbs-NVT ensembles to analyze their performance differences and results consistency. As theoretically predicted, the agreement between the simulations implies that Gibbs-NVT can be used to validate Gibbs-NPT predictions when experimental data is not available

  3. Phase-coexistence simulations of fluid mixtures by the Markov Chain Monte Carlo method using single-particle models

    KAUST Repository

    Li, Jun

    2013-09-01

    We present a single-particle Lennard-Jones (L-J) model for CO2 and N2. Simplified L-J models for other small polyatomic molecules can be obtained following the methodology described herein. The phase-coexistence diagrams of single-component systems computed using the proposed single-particle models for CO2 and N2 agree well with experimental data over a wide range of temperatures. These diagrams are computed using the Markov Chain Monte Carlo method based on the Gibbs-NVT ensemble. This good agreement validates the proposed simplified models. That is, with properly selected parameters, the single-particle models have similar accuracy in predicting gas-phase properties as more complex, state-of-the-art molecular models. To further test these single-particle models, three binary mixtures of CH4, CO2 and N2 are studied using a Gibbs-NPT ensemble. These results are compared against experimental data over a wide range of pressures. The single-particle model has similar accuracy in the gas phase as traditional models although its deviation in the liquid phase is greater. Since the single-particle model reduces the particle number and avoids the time-consuming Ewald summation used to evaluate Coulomb interactions, the proposed model improves the computational efficiency significantly, particularly in the case of high liquid density where the acceptance rate of the particle-swap trial move increases. We compare, at constant temperature and pressure, the Gibbs-NPT and Gibbs-NVT ensembles to analyze their performance differences and results consistency. As theoretically predicted, the agreement between the simulations implies that Gibbs-NVT can be used to validate Gibbs-NPT predictions when experimental data is not available. © 2013 Elsevier Inc.

  4. Radiation response of Philippine natural rubber latex

    International Nuclear Information System (INIS)

    Our earlier work has shown that the natural rubber latex (NRL) produced and processed in the Philippines is suited for radiation vulcanization. The cast films from NRL with 50% TSC exhibited maximum tensile strengths of 25-32 MPa at 15 kGy, which is the vulcanization dose or Dv. In the manufacture of dipped NRL products, certain specifications such as %TSC, protein content and tensile properties, must be met to ensure an acceptable product. For radiation vulcanization of natural rubber latex (RVNRL) to be accepted as an alternative process, it must also meet the requirements. Thus, this paper presents additional data on the radiation response of local NRL at different total solids contents (TSC), leachable proteins from NRL films as a function of dose, and the thermal activities of irradiated natural rubber latex (INRL). Different formulations of NRL showed varying tolerances to nBA. Data showed that as %TSC increases, the maximum concentration of nBA that can be added without affecting the stability of the latex decreases. The Dv increases as the %TSC increases and the nBA content decreases. This difference in response may be attributed to a lower concentration of nBA in formulations with higher %TSC. These data indicate that the parameters in the radiation treatment will be dictated by the intended applications of INRL. The thermogravimetric data showed greater stability of INRL to thermal oxidation relative to the unirradiated NRL, which correlates directly with the tensile properties of the INRL. A radiation dose of 10 kGy increased the amount of proteins leached from cast latex films. The amount of extractable proteins did not increase significantly at higher doses. The SDS PAGE analysis of the extractable proteins from unirradiated latex film showed distinct bands. An additional band at 60 Kda appeared at 10 kGy. All these bands became diffuse at higher doses, indicating the radiolysis of the proteins

  5. Commercial irradiation of natural rubber latex

    International Nuclear Information System (INIS)

    Cost of irradiation is one of the important factor to expand industrial application of radiation vulcanized natural rubber latex (RVNRL). The irradiation cost was studied under the RCA project, RAS/8/061/1109, and reasonable cost was reported by use of single purpose latex irradiation facility of 1500 ton/year. For a market development of RVNRL, irradiation of latex of the order of 100 ton/year may be required. Construction of the single purpose pilot plant of this scale is not commercially feasible. In this stage use of contract irradiation facilities which are familiar world wide gives a solution. Radia Industry Co., Ltd. have two irradiation facilities with 1.4 MCi of Co-60 and irradiate natural rubber latex for Okamoto Industries, Inc. with use of the incremental dose irradiator which is commonly used for sterilization of medical supplies. Natural rubber latex filled in standard 20 liter plastic bags are loaded on the hanger of trolley conveyer, and irradiated without agitation. The dose uniformity was around 2, and properties of the RVNRL was reported satisfactory. The dose uniformity can be improved if special container is applied. In future it is expected to construct a larger single purpose irradiation plant to provide low cost irradiation for multi-client, or import RVNRL from RCA countries provided transportation test is successful. We have interest in electron beam valcanization. Radia Industry Co., Ltd. put an order 5 MeV, 150 kW electron beam machine and it will be operational in 1990. High penetration of 5 MeV electron beam is useful for radiation processing in the condensed media like natural rubber latex. (author)

  6. String Hypothesis for [InlineMediaObject not available: see fulltext.] Spin Chains: A Particle/Hole Democracy

    Science.gov (United States)

    Volin, Dmytro

    2012-10-01

    This paper is devoted to integrable {{{g}{l} ({n} | {m})}} spin chains, which allow for formulation of the string hypothesis. Considering the thermodynamic limit of such spin chains, we derive linear functional equations that symmetrically treat holes and particles. The functional equations naturally organize different types of excitations into a pattern equivalent to the one of Y-system, and, not surprisingly, the Y-system can be easily derived from the functional equations. The Y-system is known to contain most of the information about the symmetry of the model, therefore we map the symmetry knowledge directly to the description of string excitations. Our analysis is applicable for highest weight representations which for some choice of the Kac-Dynkin diagram have only one nonzero Dynkin label. This generalizes known results for the AdS/CFT spectral problem and for the Hubbard model.

  7. CHARACTERIZATION AND RECYCLING OF WASTE WATER FROM GUAYULE LATEX EXTRACTION

    Science.gov (United States)

    Guayule commercialization for latex production to be used in medical products and other applications is now a reality. Currently, waste water following latex extraction is discharged into evaporation ponds. As commercialization reaches full scale, the liquid waste stream from latex extraction will b...

  8. Research on the chemical mechanism in the polyacrylate latex modified cement system

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Min [The Key Laboratory of Space Applied Physics and Chemistry, Ministry of Education and Shaanxi Key Laboratory of Macromolecular Science and Technology, School of Science, Northwestern Polytechnical University, Xi' an 710072 (China); Wang, Rumin, E-mail: wangmin19@mail.nwpu.edu.cn [The Key Laboratory of Space Applied Physics and Chemistry, Ministry of Education and Shaanxi Key Laboratory of Macromolecular Science and Technology, School of Science, Northwestern Polytechnical University, Xi' an 710072 (China); Zheng, Shuirong [The Key Laboratory of Space Applied Physics and Chemistry, Ministry of Education and Shaanxi Key Laboratory of Macromolecular Science and Technology, School of Science, Northwestern Polytechnical University, Xi' an 710072 (China); Northwestern Polytechnical University–East China University of Science and Technology Combined Research Institute of New High Speed Railway Materials (China); Farhan, Shameel; Yao, Hao; Jiang, Hao [The Key Laboratory of Space Applied Physics and Chemistry, Ministry of Education and Shaanxi Key Laboratory of Macromolecular Science and Technology, School of Science, Northwestern Polytechnical University, Xi' an 710072 (China)

    2015-10-15

    In this paper, the chemical mechanism in the polyacrylate latex modified cement system was investigated by Fourier transform infrared spectra (FT-IR), X-ray photoelectron spectroscopy (XPS), gel permeation chromatography (GPC) and compact pH meter. All results have shown that the chemical reactions in the polyacrylate modified system can be divided into three stages. The hydration reactions of cement can produce large amounts of Ca(OH){sub 2} (calcium hydroxide) and lead the whole system to be alkali-rich and exothermic at the first stage. Subsequently, this environment can do great contributions to the hydrolysis of ester groups in the polyacrylate chains, resulting in the formation of carboxyl groups at the second stage. At the third stage, the final crosslinked network structure of the product was obtained by the reaction between the carboxyl groups in the polyacrylate latex chains and Ca(OH){sub 2}.

  9. Research on the chemical mechanism in the polyacrylate latex modified cement system

    International Nuclear Information System (INIS)

    In this paper, the chemical mechanism in the polyacrylate latex modified cement system was investigated by Fourier transform infrared spectra (FT-IR), X-ray photoelectron spectroscopy (XPS), gel permeation chromatography (GPC) and compact pH meter. All results have shown that the chemical reactions in the polyacrylate modified system can be divided into three stages. The hydration reactions of cement can produce large amounts of Ca(OH)2 (calcium hydroxide) and lead the whole system to be alkali-rich and exothermic at the first stage. Subsequently, this environment can do great contributions to the hydrolysis of ester groups in the polyacrylate chains, resulting in the formation of carboxyl groups at the second stage. At the third stage, the final crosslinked network structure of the product was obtained by the reaction between the carboxyl groups in the polyacrylate latex chains and Ca(OH)2

  10. Magneto-optical granulometry: on the determination of the statistics of magnetically induced particle chains in concentrated ferrofluids from linear dichroism experiments

    OpenAIRE

    Socoliuc, V.; Popescu, L. B.

    2014-01-01

    An analytical theoretical model for the influence of the magnetically induced nanoparticle chaining on the linear dichroism in ferrofluids was developed. The model is based on a statistical theory for magnetic nanoparticle chaining in ferrofluids. Together with appropriate experimental approach and data processing strategy, the model grounds a magneto-optical granulometry method able to determine the magnetic field dependence of the statistics of magnetically induced particle chains in concen...

  11. Field-induced structures in miscible ferrofluid suspensions with and without latex spheres

    International Nuclear Information System (INIS)

    We explore magnetic-field-induced ordering and microphase separation of aqueous ferrofluid and of aqueous mixtures of ferrofluid with nonmagnetic latex spheres. The ferrofluid is a surfactant stabilized aqueous suspension of magnetite (Fe3O4) particles with average diameter 20 nm (including the ∼2.5-nm thick surfactant layer); the nonmagnetic latex spheres are charge stabilized polymethylmethacrylate (PMMA) particles with diameters of 42 nm, 108 nm, and 220 nm. In the presence of a uniform magnetic field, needlelike ferrofluid droplets formed that eventually grew to sample-traversing columns at fields of ∼600 G; the two-dimensional structure of these columns was, however, glassy rather than hexagonal. In higher fields, ∼1000 G, the columns stretched and coalesced into sheetlike striped liquids, but a true lamellar phase was not observed. The addition of nonmagnetic latex spheres to the ferrofluid suspension lowered substantially the critical field for the formation of columns, and induced lamellar (stripe) phases at relatively low applied fields. Image analysis was used to determine the spatial correlation functions, the average needle or column spacing, and the average lamellae spacing of these samples as a function of latex sphere size and concentration

  12. A Particle Swarm Optimization Algorithm for Optimal Operating Parameters of VMI Systems in a Two-Echelon Supply Chain

    Science.gov (United States)

    Sue-Ann, Goh; Ponnambalam, S. G.

    This paper focuses on the operational issues of a Two-echelon Single-Vendor-Multiple-Buyers Supply chain (TSVMBSC) under vendor managed inventory (VMI) mode of operation. To determine the optimal sales quantity for each buyer in TSVMBC, a mathematical model is formulated. Based on the optimal sales quantity can be obtained and the optimal sales price that will determine the optimal channel profit and contract price between the vendor and buyer. All this parameters depends upon the understanding of the revenue sharing between the vendor and buyers. A Particle Swarm Optimization (PSO) is proposed for this problem. Solutions obtained from PSO is compared with the best known results reported in literature.

  13. Preparation of highly stabilised natural rubber latex for radiation vulcanisation

    International Nuclear Information System (INIS)

    There is a bright future for radiation vulcanised natural rubber latex (RVNRL) but there are problems in manufacturing it as the centrifuged latex to be used for radiation has to be kept for at least a month or sometimes even three to six months before adding the sensitisers and even then the latex sometimes coagulates on adding the sensitisers. This paper describes a process by which the latex can be stabilised by addition of an anionic soap before centrifuging so that it has a high mechanical stability and hence can be used even within one week of the manufacture of the centrifuged latex

  14. Transmissivities of radiation beams and particle beams in multicomponent mixed materials. 2. Finite Markov chain model

    International Nuclear Information System (INIS)

    This paper is a complement to an earlier paper on the transmissivity of beams in multi-component mixed materials of identical grain size and presents an analytical expression of transmissivity based on the finite Markov chain in the case of mixed materials of different grain sizes. The expression is represented by the flux vector and the response matrix obtained from the transition matrix. (author)

  15. Latex allergy in dentistry: clinical cases report

    NARCIS (Netherlands)

    D.P. Raggio; L.B. Camargo; G.M.C.C. Naspitz; G.T. Politano; C.C. Bonifacio; F.M. Mendes; F. Kierstman

    2010-01-01

    Generally natural rubber latex (NRL) allergy is detected after some exposition to the material. As NRL is commonly found in different materials used daily in dental clinic, the allergy can be manifested in the pediatric dentistry clinic. The first clinical manifestation can be smooth but also severe

  16. Radiation vulcanization of Philippine natural rubber latex

    International Nuclear Information System (INIS)

    The response of Philippine natural rubber latex to radiation vulcanization and the stability of the irradiated natural rubber latex (INRL) upon storage and aging were investigated. Commercially available high ammonia (HA) concentrated lattices obtained from various rubber plantations in Mindanao Island were treated with 5 phr of n-butyl acrylate (nBA), and gamma-irradiated at the PNRI sup 60 Co irradiation facility at dose rate of 2.57 KGy/hr. Unirradiated cast latex films gave different green strength which varied from 2 - 11 MPa. Cast films from INRL exhibited maximum tensile strengths of 25 - 32 MPa at a radiation dose of 15 kGy. Higher tensile strengths were obtained from cast films with low Mg and high nitrogen contents. Thermal analysis using thermogravimetry (TG) revealed one major decomposition product at 374 degree C - 377 degree C. Its rate of decomposition decreased to a minimum at 15 kGy, then increased as radiation dose increased. This trend correlated well with the tensile strength measurements. The stability of the INRL upon storage and aging is an essential parameter to the rubber latex industry. For storage studies, INRL was stored for various periods of time. It was found that the pH and total solids content of the stored INRL did not change significantly after 12 months of storage; the MST values remained at above 100 seconds, and the viscosity decreased with time. The cast films exhibited a decline in tensile strength, modulus 300% and crosslinking density upon storage. While there were observed changes in the physical properties of the IRNL during the storage period, the data indicate that these properties were within values acceptable to the latex industry. Tests on the aging properties of INRL film were undertaken. It was shown that among the chemical antioxidants presently used by the latex industry. TNPP demonstrated the highest antioxidant property, followed by Antage DAHQ and Vulcanox BKF. Our data indicate that the natural rubber latex

  17. In vitro Transient Expression System of Latex C-serum was used for Analysis of Hevein Promoter in Response to Abscisic Acid in Hevea brasiliensis

    Institute of Scientific and Technical Information of China (English)

    Xiao-Wen Fei; Xiao-Dong Deng

    2008-01-01

    Hevein has been found to be an essential element in coagulation of rubber particles in latex of rubber trees. In a previous study, we cloned a 1 241-bp fragment of a 5' upstream region of the hevein gene by genome walking. This fragment was analyzed by a 5' end nested deletion method in the present study, fused with a uidA (gus) gene to produce a series of tested constructs, which were transferred into C-serum of latex and the Gus activities were detected. Results showed that the fragment from -749 to -292 was sufficient for expression of gus gene in latex, and the fragment from -292 to -168 was crucial in response to abscisic acid inducement. In a transient transgenic test of rubber leaf with particle bombardment, construct Hev749 conferred gus-specific expression in veins, in which the latex tubes mainly distributed. This implies that the fragment from -749 to -292 was laticiferous-specific.

  18. Triterpenoid biosynthesis in Euphorbia lathyris latex

    International Nuclear Information System (INIS)

    The structures of triterpenols, not previously been known, from Euphorbia lathyris latex are reported. A method for quantifying very small amounts of these compounds was developed. Concerning the biochemistry of the latex, no exogenous cofactors were required for the biosynthesis and the addition of compounds such as NADPAH and ATP do not stimulate the biosynthesis. The addition of DTE or a similar anti-oxidant was found to help reduce the oxidation of the latex, thus increasing the length of time that the latex remains active. The requirement of a divalent cation and the preference for Mn in the pellet was observed. The effect of several inhibitors on the biosynthesis of the triterpenoids was examined. Mevinolin was found to inhibit the biosynthesis of the triterpenoids from acetate, but not mevalonate. A dixon plot of the inhibition of acetate incorporation showed an I50 concentration of 3.2 μM. Fenpropimorph was found to have little or no effect on the biosynthesis. Tridemorph was found to inhibit the biosynthesis of all of the triterpenoids with an I50 of 4 μM. It was also observed that the cyclopropyl containing triterpenols, cycloartenol and 24-methylenecycloartenol were inhibited much more strongly than those containing an 8-9 double bond, lanosterol and 24-methylenelanosterol. The evidence indicates, but does not definetely prove, that lanosterol and 24-methylenelanosterol are not made from cycloartenol and 24-methylenecycloartenol via a ring-opening enzyme such as cycloeucalenol-obtusifoliol isomerase. The possibilty that cycloartenol is made via lanosterol was investigated by synthesizing 4-R-4-3H-mevalonic acid and incubating latex with a mixture of this and 14C-mevalonic acid. From the 3H/14C ratio it was shown that cycloartenol and 24-methylenecycloartenol are not made via an intermediate containing as 8-9 double bond. 88 refs., 15 figs., 30 tabs

  19. Triterpenoid biosynthesis in Euphorbia lathyris latex

    Energy Technology Data Exchange (ETDEWEB)

    Hawkins, D.R.

    1987-11-01

    The structures of triterpenols, not previously been known, from Euphorbia lathyris latex are reported. A method for quantifying very small amounts of these compounds was developed. Concerning the biochemistry of the latex, no exogenous cofactors were required for the biosynthesis and the addition of compounds such as NADPAH and ATP do not stimulate the biosynthesis. The addition of DTE or a similar anti-oxidant was found to help reduce the oxidation of the latex, thus increasing the length of time that the latex remains active. The requirement of a divalent cation and the preference for Mn in the pellet was observed. The effect of several inhibitors on the biosynthesis of the triterpenoids was examined. Mevinolin was found to inhibit the biosynthesis of the triterpenoids from acetate, but not mevalonate. A dixon plot of the inhibition of acetate incorporation showed an I/sub 50/ concentration of 3.2 ..mu..M. Fenpropimorph was found to have little or no effect on the biosynthesis. Tridemorph was found to inhibit the biosynthesis of all of the triterpenoids with an I/sub 50/ of 4 ..mu..M. It was also observed that the cyclopropyl containing triterpenols, cycloartenol and 24-methylenecycloartenol were inhibited much more strongly than those containing an 8-9 double bond, lanosterol and 24-methylenelanosterol. The evidence indicates, but does not definetely prove, that lanosterol and 24-methylenelanosterol are not made from cycloartenol and 24-methylenecycloartenol via a ring-opening enzyme such as cycloeucalenol-obtusifoliol isomerase. The possibilty that cycloartenol is made via lanosterol was investigated by synthesizing 4-R-4-/sup 3/H-mevalonic acid and incubating latex with a mixture of this and /sup 14/C-mevalonic acid. From the /sup 3/H//sup 14/C ratio it was shown that cycloartenol and 24-methylenecycloartenol are not made via an intermediate containing as 8-9 double bond. 88 refs., 15 figs., 30 tabs.

  20. Position dependence of the particle density in a double-chain section of a linear network in a totally asymmetric simple exclusion process

    Science.gov (United States)

    Pesheva, N. C.; Brankov, J. G.

    2013-06-01

    We report here results on the study of the totally asymmetric simple exclusion process, defined on an open network, consisting of head and tail simple-chain segments with a double-chain section inserted in between. Results of numerical simulations for relatively short chains reveal an interesting feature of the network. When the current through the system takes its maximum value, a simple translation of the double-chain section forward or backward along the network leads to a sharp change in the shape of the density profiles in the parallel chains, thus affecting the total number of particles in that part of the network. In the symmetric case of equal injection and ejection rates α=β>1/2 and equal lengths of the head and tail sections, the density profiles in the two parallel chains are almost linear, characteristic of the coexistence line (shock phase). Upon moving the section forward (backward), their shape changes to the one typical for the high- (low-) density phases of a simple chain. The total bulk density of particles in a section with a large number of parallel chains is evaluated too. The observed effect might have interesting implications for the traffic flow control as well as for biological transport processes in living cells. An explanation of this phenomenon is offered in terms of a finite-size dependence of the effective injection and ejection rates at the ends of the double-chain section.

  1. Synthesis and Characterization of Poly(St-co-BA) Latex with an Organic-Inorganic Hybrid Compound as Emulsifier

    Institute of Scientific and Technical Information of China (English)

    袁俊杰; 周树学; 廖建和; 武利民

    2003-01-01

    A poly (St-co-BA) latex was successfully synthesized by using an organic-inorganic hybrid compound (OIHC), an aliphatic carboxylate sodium/nano-silica composite, as the emulsifier, and investigated by particle size analyzer, transmission electron microscope (TEM), optical contact angle measurement (OCA) and dynamic mechanical analyzer (DMA). It was found that the protective agent, sodium polyacrylate (PA),could obviously improve the polymerization stability and the functional monomer, glycidyl methacrylate (GMA), could enhance the store stability of the latex. The particle size of poly(St-co-BA) latex decreased and then leveled off as OIHC content increased. TEM shows that the prepared polymers were a~:tually organic-inorganic nanocomposites, and these films have better waterproof property than those prepared by traditional poly(St-co-BA) latex or organic silicone modified poly(St-co-BA) latex. The nanocomposite polymer has much higher glass transition temperature than organic silicone modified poly(St-co-BA) polymer containing the same organic silicone content.

  2. PMMA-N,N,N-trimethyl chitosan nanoparticles for fabrication of antibacterial natural rubber latex gloves.

    Science.gov (United States)

    Arpornwichanop, Thanida; Polpanich, Duangporn; Thiramanas, Raweewan; Suteewong, Teeraporn; Tangboriboonrat, Pramuan

    2014-08-30

    This paper presents one-pot synthesis of N,N,N-trimethyl chitosan (TMC) stabilized poly(methyl methacrylate) (PMMA) latex particles via the miniemulsion polymerization technique. From (1)H NMR, synthesized TMC contains 52% degree of quaternization. Compared to native biopolymer chitosan, TMC possesses permanently positive charges as well as provides greater antibacterial activity. Combining properties of PMMA and TMC, PMMA-TMC latex nanoparticles (hydrodynamic size ≈282 nm) could be used in place of inorganic lubricating powder in fabrication of latex gloves at pH ≥ 7. After immersing sulphur prevulcanized natural rubber (SPNR) film into 3 wt% of PMMA-TMC latex at pH 7, significant amount of nanoparticles uniformly deposited onto SPNR film was observed under SEM. A number of nanoparticles present on film surface would increase surface roughness of the rubber film and potentially inhibit the bacterial (Escherichia coli and Staphylococcus aureus) growth, which would be useful for fabrication of special gloves with antibacterial property. PMID:24815393

  3. Experimental modeling of polymer latex spray coating for producing controlled-release urea

    Institute of Scientific and Technical Information of China (English)

    Rui Lan; Yonghui Liu; Guanda Wang; Tingjie Wang; Chengyou Kan; Yong Jin

    2011-01-01

    Spray coating of polymer latex onto fertilizer particles in a fluidized bed for producing controlled-release urea is an environment friendly technology as it does not need any toxic organic solvent.Since the spray coating process in a fluidized bed occurs in the presence of particle collisions,the coating of the particles is random,intermittent and multiple,thus making it difficult to investigate the film formation process.In this paper,an experimental model apparatus was designed and used to investigate the effects of the key factors in the spray coating process.This apparatus reasonably simplified the complex process to avoid particle collisions and randomness in the coating.The intermittent coating in the fluidized bed was modeled by periodic coating and dewatering in the experimental apparatus.A large area film was obtained,and the film permeability was measured.The effects of atomizing gas flow rate,spray rate of latex,solid content of latex and gas temperature on film structure and film permeability were investigated.It was found that water transfer played a dominant role in the spray coating process.

  4. INFLUENCE OF THE VOLATILE FATTY ACID CONTENT TO RADIATION VULCANIZED NATURAL RUBBER LATEX (RVNRL

    Directory of Open Access Journals (Sweden)

    CHIRINOS, Hugo David

    2012-01-01

    Full Text Available Natural rubber latex is a dispersion of natural rubber particles in water. These particles are coated with aprotein layer which will stabilize the dispersion in water by forming an electric charge in the layer. Any differentcondition affecting this layer disturbs the stability of dispersion. Microorganism attack disturbs the protein layerand consequently the stability of the dispersion. By adding 1.2% by weight of NH3, the stability of the dispersioncan be improved. The fresh latex was irradiated by Co-60 with irradiation dose of 10, 20, 30, 40 and 100 kGy.The results showed a relationship between the volatile fatty acid content (VFA, product from microorganismattack on carbohydrate and the green strength or the physical properties of vulcanized film. Low VFA numbershowing a higher physical strength of the film either un-vulcanized or vulcanized. It appeared that the structurewas responsible in yielding a good physical property of the film.

  5. Production of Natural Rubber Grafted Styrene Copolymer Latex as Water Base Coatings

    Directory of Open Access Journals (Sweden)

    M Utama

    2006-07-01

    Full Text Available Twelve kinds formulation of natural rubber grafted copolymer styrene (NR-g-S prepared by gamma radiation co-polymerization technique has been carried out. The characteristic of NR-g-S and its water base coating such as molecular structure, particle size, and the properties of latex and its film were evaluated. The results showed that the NR-g-S latex as a water base coating has low viscosity, height strength, good grease resistance, good flexibility, good aging and corrosion resistance on concrete cement and metal. The average particle size is between 270-300 nm, and the bonding between poly-isoprene of NRL and styrene molecules were grafted copolymer

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

    Science.gov (United States)

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

    2016-04-25

    Stable latexes of hierarchically organized core-cross-linked polymer micelles that are functionalized at the core with triphenylphosphine (TPP@CCM) have been investigated by NMR spectroscopic analysis at both natural (ca. pH 5) and strongly basic (pH 13.6) pH values after core swelling with toluene. The core-shell interface structuring forces part of the hydrophilic poly(ethylene oxide) (PEO) chains to reside inside the hydrophobic core at both pH values. Loading the particle cores with [Rh(acac)(CO)2 ] (acac=acetylacetonate) at various Rh/P ratios yielded polymer-supported [Rh(acac)(CO)(TPP)] (TPP=triphenylphosphine). The particle-to-particle rhodium migration is very fast at natural pH, but slows down dramatically at high pH, whereas the size distribution of the nanoreactors remains unchanged. The slow migration at pH 13.6 leads to the generation of polymer-anchored [Rh(OH)(CO)(TPP)2 ], which is also generated immediately upon the addition of NaOH to the particles with a [Rh(acac)(CO)] loading of 50 %. Similarly, treatment of the same particles with NaCl yielded polymer-anchored [RhCl(CO)(TPP)2 ]. Interparticle coupling occurs during these rapid processes. These experiments prove that the major contribution to metal migration is direct core-core contact. The slow migration at the high pH value, however, must result from a pathway that does not involve core-core contact. The facile penetration of the polymer cores by NaOH and NaCl results from the presence of shell-linked poly(ethylene oxide) methyl ether functions both outside and inside the polymer core-shell interface. PMID:27001452

  7. Resonant transmission of light in chains of high-index dielectric particles

    Science.gov (United States)

    Savelev, Roman S.; Filonov, Dmitry S.; Petrov, Mihail I.; Krasnok, Alexander E.; Belov, Pavel A.; Kivshar, Yuri S.

    2015-10-01

    We study numerically, analytically, and experimentally the resonant transmission of light in a waveguide formed by a periodic array of high-index dielectric nanoparticles with a side-coupled resonator. We demonstrate that a resonator with high enough Q -factor provides the conditions for the Fano-type interference allowing one to control the resonant transmission of light. We suggest a practical realization of this resonant effect based on the quadrupole resonance of a dielectric particle and demonstrate it experimentally for ceramic disks at microwave frequencies.

  8. Thermodynamics of polymer nematics described with a worm-like chain model: particle-based simulations and SCF theory calculations

    Science.gov (United States)

    Greco, Cristina; Yiang, Ying; Kremer, Kurt; Chen, Jeff; Daoulas, Kostas

    Polymer liquid crystals, apart from traditional applications as high strength materials, are important for new technologies, e.g. Organic Electronics. Their studies often invoke mesoscale models, parameterized to reproduce thermodynamic properties of the real material. Such top-down strategies require advanced simulation techniques, predicting accurately the thermodynamics of mesoscale models as a function of characteristic features and parameters. Here a recently developed model describing nematic polymers as worm-like chains interacting with soft directional potentials is considered. We present a special thermodynamic integration scheme delivering free energies in particle-based Monte Carlo simulations of this model, avoiding thermodynamic singularities. Conformational and structural properties, as well as Helmholtz free energies are reported as a function of interaction strength. They are compared with state-of-art SCF calculations invoking a continuum analog of the same model, demonstrating the role of liquid-packing and fluctuations.

  9. Proteolytic properties of Funastrum clausum latex.

    Science.gov (United States)

    Morcelle, Susana R; Caffini, Néstor O; Priolo, Nora

    2004-07-01

    As part of a screening of latex endopeptidases from plants growing in Argentina, the presence of proteolytic activity in the latex of Funastrum clausum stems is reported. The proteases present in the crude extract showed the main characteristics of the cysteine proteolytic class, i.e. optimum pH at alkaline range, isoelectric point (pI) higher than 9.0, and inhibition of proteolytic activity by thiol blocking reagents. A remarkable thermal stability was also evident in the crude extract. Endosterolytic preference tried on p-nitrophenyl esters of N-alpha-carbobenzoxy-L-amino acids was higher for the alanine, asparagine and tyrosine derivatives. Preliminary peptidase purification by two-step ionic exchange showed the presence of two proteolytic fractions with molecular masses of approximately 24.0 kDa according to SDS-PAGE. PMID:15261386

  10. Designing a Multistage Supply Chain in Cross-Stage Reverse Logistics Environments: Application of Particle Swarm Optimization Algorithms

    Directory of Open Access Journals (Sweden)

    Tzu-An Chiang

    2014-01-01

    Full Text Available This study designed a cross-stage reverse logistics course for defective products so that damaged products generated in downstream partners can be directly returned to upstream partners throughout the stages of a supply chain for rework and maintenance. To solve this reverse supply chain design problem, an optimal cross-stage reverse logistics mathematical model was developed. In addition, we developed a genetic algorithm (GA and three particle swarm optimization (PSO algorithms: the inertia weight method (PSOA_IWM, VMax method (PSOA_VMM, and constriction factor method (PSOA_CFM, which we employed to find solutions to support this mathematical model. Finally, a real case and five simulative cases with different scopes were used to compare the execution times, convergence times, and objective function values of the four algorithms used to validate the model proposed in this study. Regarding system execution time, the GA consumed more time than the other three PSOs did. Regarding objective function value, the GA, PSOA_IWM, and PSOA_CFM could obtain a lower convergence value than PSOA_VMM could. Finally, PSOA_IWM demonstrated a faster convergence speed than PSOA_VMM, PSOA_CFM, and the GA did.

  11. Ground State Geometries of Polyacetylene Chains from Many-Particle Quantum Mechanics.

    Science.gov (United States)

    Barborini, Matteo; Guidoni, Leonardo

    2015-09-01

    Due to the crucial role played by electron correlation, the accurate determination of ground state geometries of π-conjugated molecules is still a challenge for many quantum chemistry methods. Because of the high parallelism of the algorithms and their explicit treatment of electron correlation effects, Quantum Monte Carlo calculations can offer an accurate and reliable description of the electronic states and of the geometries of such systems, competing with traditional quantum chemistry approaches. Here, we report the structural properties of polyacetylene chains H-(C₂H₂)(N)-H up to N = 12 acetylene units, by means of Variational Monte Carlo (VMC) calculations based on the multi-determinant Jastrow Antisymmetrized Geminal Power (JAGP) wave function. This compact ansatz can provide for such systems an accurate description of the dynamical electronic correlation as recently detailed for the 1,3-butadiene molecule [J. Chem. Theory Comput. 2015 11 (2), 508-517]. The calculated Bond Length Alternation (BLA), namely the difference between the single and double carbon bonds, extrapolates, for N → ∞, to a value of 0.0910(7) Å, compatible with the experimental data. An accurate analysis was able to distinguish between the influence of the multi-determinantal AGP expansion and of the Jastrow factor on the geometrical properties of the fragments. Our size-extensive and self-interaction-free results provide new and accurate ab initio references for the structures of the ground state of polyenes. PMID:26405437

  12. IDENTIFICATION OF BACTERIA IN LATEX PAINTS

    OpenAIRE

    Rojas, J

    2008-01-01

    The bacteria are prokaryote organisms with a high capacity to colonize many types of habits. This research was developed with the object to identify extremophiles bacteria presents in latex paint. The bacteria were cultivated in culture mediums TSA, Blood Agar, Mc Conkey and finally the biochemical proof API-NF® for bacteria's isolation and identification, respectively. Characterization showed bacterial profile of Pasteurella sp. Hypothesis that could be found extremophiles bac...

  13. A hybrid particle swarm optimization and genetic algorithm for closed-loop supply chain network design in large-scale networks

    DEFF Research Database (Denmark)

    Soleimani, Hamed; Kannan, Govindan

    2015-01-01

    Today, tracking the growing interest in closed-loop supply chain shown by both practitioners and academia is easily possible. There are many factors, which transform closed-loop supply chain issues into a unique and vital subject in supply chain management, such as environmental legislation...... proposed and a complete validation process is undertaken using CPLEX and MATLAB software. In small instances, the global optimum points of CPLEX for the proposed hybrid algorithm are compared to genetic algorithm, and particle swarm optimization. Then, in small, mid, and large-size instances, performances...

  14. Estimation of effective permeability for magnetoactive composites containing multi-chain-structured particles based on the generalized Mori–Tanaka approach

    International Nuclear Information System (INIS)

    We present an analytic approach to evaluate the effective permeability of multi-chain-structured magnetic particle-filled composites which is formulated by a microstructure-based double-inclusion magnetic model with the generalized Mori–Tanaka theorem. The local magnetic field in a representative volume element (RVE) containing multi-chain-structured particles is derived by using a modified Green’s function. The average fields in the particles, in a matrix coated by particles, and in an effective medium far away from particles are rendered by homogenization of the local magnetic distributions. By means of the relation between the average magnetic field and induction, the effective magnetic permeability of magnetoactive composites is explicitly derived; it exhibits anisotropic and universal behavior. The proposed model has been compared with the available experimental data and other microstructure-based models in the literature; it shows good agreement and gives reliable predictions for magnetic particle-filled composites, especially in terms of capturing the magnetic anisotropic characteristics with respect to the multi-chain-structured particle distribution. (paper)

  15. New approach for papaya latex storage without virus degradation

    OpenAIRE

    Silas P. Rodrigues; Andrade, Josemar S.; José A. Ventura; Fernandes, Patricia M. B.

    2009-01-01

    Papaya meleira virus (PMeV) is the causal agent of papaya (Carica papaya L.) sticky disease, which has been detected through analysis of its double-stranded RNA (dsRNA) genome from plant latex. In this work we demonstrate that PMeV dsRNA is protected during 25 days when latex is diluted in citrate buffer pH 5.0 (1:1 v/v) and maintained at -20ºC. At the same temperature, some protection was observed for pure latex or latex diluted in ultra-pure water. Conversely, the dsRNA was almost completel...

  16. New constitutive latex osmotin-like proteins lacking antifungal activity.

    Science.gov (United States)

    Freitas, Cleverson D T; Silva, Maria Z R; Bruno-Moreno, Frederico; Monteiro-Moreira, Ana C O; Moreira, Renato A; Ramos, Márcio V

    2015-11-01

    Proteins that share similar primary sequences to the protein originally described in salt-stressed tobacco cells have been named osmotins. So far, only two osmotin-like proteins were purified and characterized of latex fluids. Osmotin from Carica papaya latex is an inducible protein lacking antifungal activity, whereas the Calotropis procera latex osmotin is a constitutive antifungal protein. To get additional insights into this subject, we investigated osmotins in latex fluids of five species. Two potential osmotin-like proteins in Cryptostegia grandiflora and Plumeria rubra latex were detected by immunological cross-reactivity with polyclonal antibodies produced against the C. procera latex osmotin (CpOsm) by ELISA, Dot Blot and Western Blot assays. Osmotin-like proteins were not detected in the latex of Thevetia peruviana, Himatanthus drasticus and healthy Carica papaya fruits. Later, the two new osmotin-like proteins were purified through immunoaffinity chromatography with anti-CpOsm immobilized antibodies. Worth noting the chromatographic efficiency allowed for the purification of the osmotin-like protein belonging to H. drasticus latex, which was not detectable by immunoassays. The identification of the purified proteins was confirmed after MS/MS analyses of their tryptic digests. It is concluded that the constitutive osmotin-like proteins reported here share structural similarities to CpOsm. However, unlike CpOsm, they did not exhibit antifungal activity against Fusarium solani and Colletotrichum gloeosporioides. These results suggest that osmotins of different latex sources may be involved in distinct physiological or defensive events. PMID:26231325

  17. Study on radiation vulcanization of natural rubber latex

    Institute of Scientific and Technical Information of China (English)

    ZhuNan-Kang; MakuuchiK; 等

    1997-01-01

    The effect of dose rate of 60Co γ-ray on radiation vulacnization of natural rubber latex is studied using Malysian latex with 0.002 mass fraction KOH and 0.05 mass fraction n-BA.Results show that,when radiation doses are 20 and 15kGy,only that the dose rates are greater than 0.49 and 1.6 kGY/h,respectively can make the tensile strength of latex film meet the related standard;besides,storage time of radiation vulcanization latex has no effect on physical properties of the film.

  18. Aspects of Degradability and Aging of Natural Rubber Latex Films Obtained by Induced Ionizing Radiation Processes of Latex Vulcanization

    International Nuclear Information System (INIS)

    This study refers to the degradability of NRLF, natural rubber latex films, obtained by ionizing radiation. Three types of NRLF were prepared: irradiated latex, irradiated latex with about 1% of soy lecithin and sulfur-vulcanized latex, by cold vulcanization process. The films were buried in vases of two different kinds of soil: common soil and common soil with earthworm humus. Fast aging tests in laboratory with exposition to ultraviolet rays were done in irradiated latex films and irradiated latex films with soy lecithin. The results obtained after ten months of tests with buried films agree with the results of the fast aging tests, showing singularities of each type of soil and each kind of latex process. It also shows how weather inclemency can induce the films degradation process. The sulfur-vulcanized films were weakly degraded when buried. The films with lecithin and buried in vase with only common soil showed the biggest mass loss, but the films with lecithin buried in vases with common earthworm humus and soil increased their weigh and dimensions due to fungi formation. The irradiated latex films are more degradable then the sulfur-vulcanized films. The irradiated latex film, unlike the sulfur vulcanized film, showed high fungi colonization when buried. We conclude that the irradiated latex films are more easily biodegradable than the sulfur vulcanized latex films. The biodegradability increases with the addition of small amounts of soy lecithin (∼1%). The mechanical resistance of the buried films decreased related to the non-buried ones, proving that the outdoor aging in soil and the presence of fungi in the films can modify the mechanical properties of the irradiated latex owing to the biodegradation

  19. Mass spectrometric characterization of the rubber elongation factor - major allergen in natural latex gloves

    International Nuclear Information System (INIS)

    have a remarkable effect on the detection of these compounds and possibly also on the allergen characteristics of the products. Different methods for the extraction of the proteins from the natural latex products were tested in chapter 4.3. The results of the electrophoretic and chromatographic investigations of the extracts showed, that the use of the strong anionic detergent, sodium dodecyl sulfat (SDS), is essential for the extraction of the hydrophobic, particle associated proteins. The temperature and duration of the process were optimized with respect to the amount of the extracted proteins. Chapter 4.4. deals with the chromatographic, electrophoretic and mass spectrometric investigation of the extract. Several bands could be revealed after the electrophoretic separation of the mixture. The chromatographic character of the extracted proteins was studied by means of reversed phase high performance liquid chromatography (HPLC). The separated fractions were further investigated by sodium dodecyl sulfat polyacrylamide electrophoresis (SDS-PAGE) and matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry. These studies showed, that the extracted proteins had hydrophobic characteristics, could be eluted only with high organic modifier content of the applied mobile phase and could not be completely separated from each other by means of reversed phase HPLC. Chapter 4.5. covers the investigation of the protein extracted from the natural latex milk. (author)

  20. Signal recognition particle receptor is a complex that contains two distinct polypeptide chains

    International Nuclear Information System (INIS)

    Signal recognition particle (SRP) and SRP receptor are known to be essential components of the cellular machinery that targets nascent secretory proteins to the endoplasmic reticulum (ER) membrane. Here the authors report that the SRP receptor contains, in addition to the previously identified and sequenced 69-kD polypeptide (α-subunit, SRα), a 30-kD β-subunit SRβ). When SRP receptor was purified by SRP-Sepharose affinity chromatography, they observed the co-purification of two other ER membrane proteins. Both proteins are ∼30 kD in size and are immunologically distinct from each other, as well as from SRα and SRP proteins. One of the 30-kD proteins (SRβ) forms a tight complex with SRα in detergent solution that is stable to high salt and can be immunoprecipitated with antibodies to either SRα or SRβ. Both subunits are present in the ER membrane in equimolar amounts and co-fractionate in constant stoichiometry when rough and smooth liver microsomes are separated on sucrose gradients. They therefore conclude that SRβ is an integral component of SRP receptor. The presence of SRβ was previously masked by proteolytic breakdown products of SRα observed by others and by the presence of another 30-kD ER membrane protein (mp30) which co-purifies with SRα. Mp30 binds to SRP-Sepharose directly and is present in the ER membrane in several-fold molar excess of SRα and SRβ. The affinity of mp30 for SRP suggests that it may serve a yet unknown function in protein translocation

  1. Initiator Systems Effect on Particle Coagulation and Particle Size Distribution in One-Step Emulsion Polymerization of Styrene

    OpenAIRE

    Baijun Liu; Yajun Wang; Mingyao Zhang; Huixuan Zhang

    2016-01-01

    Particle coagulation is a facile approach to produce large-scale polymer latex particles. This approach has been widely used in academic and industrial research owing to its higher polymerization rate and one-step polymerization process. Our work was motivated to control the extent (or time) of particle coagulation. Depending on reaction parameters, particle coagulation is also able to produce narrowly dispersed latex particles. In this study, a series of experiments were performed to investi...

  2. Latex allergy in Bozyaka Social Security Hospital workers, Turkey

    Institute of Scientific and Technical Information of China (English)

    Kose Sukran; MandIraclo(g)glu Aliye

    2004-01-01

    @@ Latex glove used in healthcare settings has risen dramatically since around 1987. The increased threat of contracting HIV, hepatitis B, and other infectious agents during the course of delivering health care to patients has created the need for barrier protection. 1 Studies have estimated that the prevalence of latex allergy in healthcare workers ranged from 2.9% up to 17%.2

  3. POTENTIAL RECYCLING OF ANTIOXIDANT SOLUTION FOR GUAYULE LATEX EXTRACTION

    Science.gov (United States)

    Commercialization of guayule for producing latex for medical products and other uses is underway. As commercialization reaches full scale, the liquid waste stream from latex extraction will potentially become an increasing problem. The objectives of this study were to evaluate the properties of the ...

  4. Concentrations and abundance ratios of long-chain alkenones and glycerol dialkyl glycerol tetraethers in sinking particles south of Java

    Science.gov (United States)

    Chen, Wenwen; Mohtadi, Mahyar; Schefuß, Enno; Mollenhauer, Gesine

    2016-06-01

    In this study, we obtained concentrations and abundance ratios of long-chain alkenones and glycerol dialkyl glycerol tetraethers (GDGTs) in a one-year time-series of sinking particles collected with a sediment trap moored from December 2001 to November 2002 at 2200 m water depth south of Java in the eastern Indian Ocean. We investigate the seasonality of alkenone and GDGT fluxes as well as the potential habitat depth of the Thaumarchaeota producing the GDGTs entrained in sinking particles. The alkenone flux shows a pronounced seasonality and ranges from 1 μg m-2 d-1 to 35 μg m-2 d-1. The highest alkenone flux is observed in late September during the Southeast monsoon, coincident with high total organic carbon fluxes as well as high net primary productivity. Flux-weighted mean temperature for the high flux period using the alkenone-based sea-surface temperature (SST) index U37K‧ is 26.7 °C, which is similar to satellite-derived Southeast (SE) monsoon SST (26.4 °C). The GDGT flux displays a weaker seasonality than that of the alkenones. It is elevated during the SE monsoon period compared to the Northwest (NW) monsoon and intermonsoon periods (approximately 2.5 times), which is probably related to seasonal variation of the abundance of Thaumarchaeota, or to enhanced export of GDGTs by aggregation with sinking phytoplankton detritus. Flux-weighted mean temperature inferred from the GDGT-based TEX86H index is 26.2 °C, which is 1.8 °C lower than mean annual (ma) SST but similar to SE monsoon SST. As the time series of TEX86H temperature estimates, however, does not record a strong seasonal amplitude, we infer that TEX86H reflects ma upper thermocline temperature at approximately 50 m water depth.

  5. Radiation vulcanization of natural rubber latex

    International Nuclear Information System (INIS)

    This paper describes the experimental techniques and the results of radiation vulcanization of natural rubber latex carried out on several high ammonia latices available in the country. The efficiency of various sensitisers and stabilisers used were evaluated in terms of the gamma radiation dose required to produce the maximum tensile strengths. The extent of crosslinking of RVNRL sample films were estimated by equilibrium swelling ratio measurements. The stability of pre-irradiated and post-irradiated samples were monitored using viscosity measurements as the parameter

  6. Assimilation of Satellite Soil Moisture observation with the Particle Filter-Markov Chain Monte Carlo and Geostatistical Modeling

    Science.gov (United States)

    Moradkhani, Hamid; Yan, Hongxiang

    2016-04-01

    Soil moisture simulation and prediction are increasingly used to characterize agricultural droughts but the process suffers from data scarcity and quality. The satellite soil moisture observations could be used to improve model predictions with data assimilation. Remote sensing products, however, are typically discontinuous in spatial-temporal coverages; while simulated soil moisture products are potentially biased due to the errors in forcing data, parameters, and deficiencies of model physics. This study attempts to provide a detailed analysis of the joint and separate assimilation of streamflow and Advanced Scatterometer (ASCAT) surface soil moisture into a fully distributed hydrologic model, with the use of recently developed particle filter-Markov chain Monte Carlo (PF-MCMC) method. A geostatistical model is introduced to overcome the satellite soil moisture discontinuity issue where satellite data does not cover the whole study region or is significantly biased, and the dominant land cover is dense vegetation. The results indicate that joint assimilation of soil moisture and streamflow has minimal effect in improving the streamflow prediction, however, the surface soil moisture field is significantly improved. The combination of DA and geostatistical approach can further improve the surface soil moisture prediction.

  7. Amplification of plasmid DNA bound on soil colloidal particles and clay minerals by the polymerase chain reaction

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Polymerase chain reaction (PCR) was used to amplify a 600-base pair (bp) sequence of plasmid pGEX-2T DNA bound on soil colloidal particles from Brown soil (Alfisol) and Red soil (Ultisol), and three different minerals (goethite, kaolinite, montmorillonite). DNA bound on soil colloids, kaolinite, and montmorillonite was not amplified when the complexes were used directly but amplification occurred when the soil colloid or kaolinite-DNA complex was diluted, 10- and 20-fold. The montmorillonite-DNA complex required at least 100-fold dilution before amplification could be detected. DNA bound on goethite was amplified irrespective of whether the complex was used directly, or diluted 10- and 20-fold. The amplification of mineral-bound plasmid DNA by PCR is, therefore, markedly influenced by the type and concentration of minerals used. This information is of fundamental importance to soil molecular microbial ecology with particular reference to monitoring the fate of genetically engineered microorganisms and their recombinant DNA in soil environments.

  8. A method for protein extraction from different subcellular fractions of laticifer latex in Hevea brasiliensis compatible with 2-DE and MS

    Directory of Open Access Journals (Sweden)

    Guo Anping

    2010-06-01

    Full Text Available Abstract Background Proteomic analysis of laticifer latex in Hevea brasiliensis has been received more significant attentions. However, the sticky and viscous characteristic of rubber latex as cytoplasm of laticifer cells and the complication of laticifer latex membrane systems has made it challenge to isolate high-quality proteins for 2-DE and MS. Results Based on the reported Borax/PVPP/Phenol (BPP protocol, we developed an efficient method for protein preparation from different latex subcellular fractions and constructed high-resolution reference 2-DE maps. The obtained proteins from both total latex and C-serum fraction with this protocol generate more than one thousand protein spots and several hundreds of protein spots from rubber particles as well as lutoid fraction and its membranes on the CBB stained 2-DE gels. The identification of 13 representative proteins on 2-DE gels by MALDI TOF/TOF MS/MS suggested that this method is compatible with MS. Conclusion The proteins extracted by this method are compatible with 2-DE and MS. This protein preparation protocol is expected to be used in future comparative proteomic analysis for natural rubber latex.

  9. Banyan latex: a facile fuel for the multifunctional properties of MgO nanoparticles prepared via auto ignited combustion route

    Science.gov (United States)

    Kumar, M. R. Anil; Nagaswarupa, H. P.; Anantharaju, K. S.; Gurushantha, K.; Pratapkumar, C.; Prashantha, S. C.; Shashishekar, T. R.; Nagabhushana, H.; Sharma, S. C.; Vidya, Y. S.; Daruka Prasad, B.; Vivek Babu, C. S.; Vishnu Mahesh, K. R.

    2015-09-01

    MgO nanoparticles (MNPs) were prepared by a solution combustion route using banyan tree (BT) latex and glycine as fuels. The powder x-ray diffraction results indicate the formation of a single cubic phase and the crystallite size obtained from transmission electron microscopy was found to be ˜10-15 nm. Scanning electron microscopy result reveals spherical-shaped particles obtained with BT latex. However, in a chemical route, porous and agglomerated particles were obtained. The energy band gap of MNPs obtained using BT latex and a chemical route were found to be in the range 4.85-5.0 eV. Photoluminescence peaks observed at 473, 514, and 588 nm when excited at 433 nm, which were attributed to surface defects. The enhanced photocatalytic activities of spherical MgO were due to smaller crystallite size, higher surface defects, dye sensitization, and capability to reduce the electron-hole pair recombination. Further, green-synthesized MNPs exhibit superior antifungal activity against various plant pathogens. The present studies demonstrated a green engineering route for the synthesis of multifunctional MNPs using BT latex.

  10. Cytotoxicity Comparison of the Nanoparticles Deposited on Latex Rubber Bands between the Original and Stretched State

    Directory of Open Access Journals (Sweden)

    Jung-Hwan Lee

    2014-01-01

    Full Text Available Understanding the biocompatibility of nanoparticles in dental materials is essential for their safe usage in the oral cavity. In this study, we investigated whether nanoparticles deposited on orthodontic latex rubber bands are involved in the induction of cytotoxicity. A method of stretching to three times (“3L” the length of the latex rubber bands was employed to detach the particles using the original length (“L” for comparison. The cytotoxicity tests were performed on extracts with mouse fibroblasts (L929 and human gingival fibroblasts (HGFs. Fourier transform infrared spectroscopy, ion chromatography, elemental analysis, and inductively coupled plasma mass spectrometry (ICP-MS were performed to detect the harmful components in the extracts from rubber bands. There was a significant decrease in the cell viability in the “L” samples compared with the “3L” samples (P<0.05 in the L929 and HGF cells. This was due to the Ni single crystal nanoparticles (~50nm from the inner surface of “L” samples that were detached in the “3L” samples as well as the Zn ion (~9 ppm detected in the extract. This study revealed that the Ni nanoparticles, as well as Zn ions, were involved in the induction of cytotoxicity from the latex rubber bands.

  11. Alison Bell Memorial Award. Latex sensitivity and allergy: fact and fiction.

    Science.gov (United States)

    Dyke, M

    1999-04-01

    Health care workers (HCW) have a higher incidence of latex sensitivity than car maintenance workers! The wearing of latex gloves over several years increases the risk of developing latex allergy! All glove related skin reactions are due to latex! People with spina bifida have a high incidence of latex sensitivity! There is a relationship between allergies to natural latex rubber and avocados, chestnuts and bananas! We should all stop using latex products! Powdered gloves are as safe as unpowdered ones, as long as they are rinsed well! PMID:10232131

  12. Size effects of latex nanomaterials on lung inflammation in mice

    International Nuclear Information System (INIS)

    Effects of nano-sized materials (nanomaterials) on sensitive population have not been well elucidated. This study examined the effects of pulmonary exposure to (latex) nanomaterials on lung inflammation related to lipopolysaccharide (LPS) or allergen in mice, especially in terms of their size-dependency. In protocol 1, ICR male mice were divided into 8 experimental groups that intratracheally received a single exposure to vehicle, latex nanomaterials (250 μg/animal) with three sizes (25, 50, and 100 nm), LPS (75 μg/animal), or LPS plus latex nanomaterials. In protocol 2, ICR male mice were divided into 8 experimental groups that intratracheally received repeated exposure to vehicle, latex nanomaterials (100 μg/animal), allergen (ovalbumin: OVA; 1 μg/animal), or allergen plus latex nanomaterials. In protocol 1, latex nanomaterials with all sizes exacerbated lung inflammation elicited by LPS, showing an overall trend of amplified lung expressions of proinflammatory cytokines. Furthermore, LPS plus nanomaterials, especially with size less than 50 nm, significantly elevated circulatory levels of fibrinogen, macrophage chemoattractant protein-1, and keratinocyte-derived chemoattractant, and von Willebrand factor as compared with LPS alone. The enhancement tended overall to be greater with the smaller nanomaterials than with the larger ones. In protocol 2, latex nanomaterials with all sizes did not significantly enhance the pathophysiology of allergic asthma, characterized by eosinophilic lung inflammation and Igs production, although latex nanomaterials with less than 50 nm significantly induced/enhanced neutrophilic lung inflammation. These results suggest that latex nanomaterials differentially affect two types of (innate and adaptive immunity-dominant) lung inflammation

  13. Radiation dose required for the vulcanization of natural rubber latex

    International Nuclear Information System (INIS)

    The radiation dose required for the vulcanization of natural rubber latex was optimized. To enhance the crosslinking, several sensitizers were used. Among the sensitizers, n-butyl acrylate (n-BA) alone was found to be the best one. The effects of concentration of n-BA, mixing and standing time of latex with n-BA on the tensile properties of latex film were investigated. 12 kGy radiation dose, 5 phr n-BA and 30-40 min of mixing time were found to be the optimum conditions for irradiation. (author)

  14. Recent developments in radiation vulcanisation of natural rubber latex

    International Nuclear Information System (INIS)

    Natural rubber latex, an important industrial raw material, is cross linked using energy of gamma radiation. To reduce the energy of radiation, sensitizers like n-butyl acrylate are used. The product so obtained is called radiation vulcanized natural rubber latex (RVNRL). This product is found to have many superior properties in comparison to the conventionally cross linked latexes. Because of the very low levels of cytotoxicity and nitrosamines in RVNRL, it is expected to be the future raw material for producing products like nipples, catheters, balloons and gloves. (author)

  15. Radiation vulcanization of natural rubber latex with low energy accelerator

    International Nuclear Information System (INIS)

    The radiation vulcanization of natural rubber latex (RVNRL) with the recently installed electron beam (EB) pilot plant at Takasaki Radiation Chemistry Research Establishment, Takasaki, Japan has been discussed. The accelerating voltage and beam current of the plant are 250 kV and 10 mA respectively. The plant has a reaction vessel with the capacity of 18 liters latex to irradiate at a time. In order to obtain a suitable setting of experimental for RVNRL under EB of the plant the parameters such as irradiation time, defoamer concentration, volume of latex, beam current etc. are being optimized by varying the individual parameter at a constant set of the other variables. (author)

  16. A latex slide agglutination test for rapid detection of antimyeloperoxidase antibody.

    OpenAIRE

    Ko, K.H.; S. S. Lee; Lawton, J W

    1999-01-01

    AIM: To develop and test a new latex slide agglutination test (MPO-LSAT) to detect antimyeloperoxidase (anti-MPO) antibody in serum. METHODS: Latex bead coating was adjusted to give maximum sensitivity by attending to latex size, MPO to latex ratio for coupling, ratio of diluted serum to MPO-latex, reaction time and temperature for coupling, and reaction time for agglutination. Inhibition studies were performed using MPO, proteinase 3, bactericidal/permeability increasing protein, and lactofe...

  17. Effect of Polyvinylpyrrolidone on the Morphologies of Latex Films and Air Permeability of the Latex Finished Fabrics

    Institute of Scientific and Technical Information of China (English)

    SHEN Yi-feng; YE Jia-jia; YANG Lei; WU Ming-hua; NI Tian-xiang

    2010-01-01

    Low air permeability is a common problem happening to the coating finished and pigment dyed fabrics.To tackle the problem,styrene and butyl acrylate copolymer latex was prepared and used as substitute for the binder.Then,polyvinylpyrrolidoue(PVP)was fed into the latex.It was expected that pores could form in the resulting latex film after being rinsed.The morphologies of the latex films were analysized by scanning electric microscope(SEM).It was found that the continuity of the latex films decreased greatly because of the addition of PVP,leading to the loss of the stress at break of the films.After rinsing with methanol aqueous solution,PVP was easily leached off and(macro)void was formed in the latex films.The size of the void decreased with the increase of the PVP concentration.Then,the latex with and without PVP was used to finish the cotton fabrics and engaged as binder in pigment dyeing.After PVP was rinsed out,the air permeability of the fabrics improved greatly,which recovered to that of the unfinished one.In the meantime,the color fastness to rubbing was little affected.So,the method of PVP addition could be termed as an efficient way to improve the air permeability in coating and dyeing industry.

  18. Production of Gum from Cashew Tree Latex

    Directory of Open Access Journals (Sweden)

    O. S. AZEEZ

    2005-06-01

    Full Text Available This research is aimed at producing gum from cashew tree latex, which can act as substitute for gum Arabic. The method used include drying and size reduction of the exudates gum, sieving of the gum to remove impurities, dissolution of the gum in distilled water, filtration to remove polysaccharide waste and finally concentration and stability of the gum. Glycerine, starch and Zinc oxide are some of the additives used in stabilizing the gum. The pH and Viscosity on addition of various percentage concentration of stabilizing agent were determined. Gum of the best quality was obtained with viscosity and pH of 4.52 Ns/m2 and 4.2 respectively; this is because the natural pH of gum from Acacia Senegal ranges between 3.9 - 4.9. The gum can be used as an alternative for synthetic adhesive used presently for stamps and envelopes.

  19. Performance of latex balloons for optical computed tomography

    Science.gov (United States)

    Jordan, K.; Walsh, A.; Peng, M.; Battista, J.

    2013-06-01

    Latex balloons filled with radiation sensitive hydrogels were evaluated as 3D dosimeters with optical computed tomography (CT) readout. Custom balloons, with less than 10 cm diameters, were made from latex sheets. Commercial, 13 cm diameter, clear balloons were investigated for larger volumes. Ferrous-xylenol orange and genipin gelatin gels selected for 1 and 30 Gy experiments, respectively. The thin stretched latex membrane allowed optical imaging to within 1 mm of the interior balloon edge. Reconstructed dose distributions demonstrated valid measurements to within 2 mm of the balloon surface. The rubber membrane provides a hybrid approach to deforming hydrogels. Uniform irradiation of a deformed gel resulted in a uniform dose being measured when scanned in the relaxed, initial balloon shape. The 13 cm diameter balloons were also effective and inexpensive vessels for hydrogels due to their high clarity, thinness and mechanical strength. Latex balloons represent an inexpensive method to obtain useful information from nearly the entire dosimeter volume.

  20. Radiation vulcanization of natural rubber latex sensitized with commercial gases

    International Nuclear Information System (INIS)

    The industrial activities using natural rubber latex are fully compatible with rural areas in Amazon and other places in Brazil, as well as in other tropical countries. However the classical sulfur vulcanization presents many occupational problems for the workers in rural areas. Radiation vulcanization of natural rubber latex is a much more friendly process as sulfur compounds are not needed for crosslinking, although chemicals as acrylate monomers, particularly multifunctional acrylates are still used as sensitizers for radiation processes. Two commercial gases, acetylene and butadiene, were selected as sensitizers for the radiation vulcanization of natural rubber latex instead of acrylates. These gases accelerate the crosslinking rates of the cure process and lower the radiation dose required to achieve vulcanization of natural rubber latex and improve the mechanical properties to reduce the tackiness of rubber goods. (author)

  1. Contact Dermatitis (Including Latex Dermatitis) (Beyond the Basics)

    Science.gov (United States)

    ... with a latex allergy should inform their doctors, dentists, and other healthcare providers about their allergy. Some ... loading the PDA software on a single Personal Digital Assistant (PDA), or by using his or her ...

  2. PREVENTION OF BIOFILM FORMATION ON NORFLOXACINMETRONIDAZOLE TREATED URETERAL LATEX STENTS

    OpenAIRE

    B. ELAYARAJAH; R. RAJENDRAN,; B. VENKATRAJAH,; WEDA SREEKUMAR,; ASASUDHAKAR,; P. K. JANIGA

    2011-01-01

    Biomaterial-associated bacterial infections present common and challenging complications with medical implants. The purpose of this study was to determine the antibacterial properties of latex rubber stents with integrated norfloxacin-metronidazole (synergistic antibacterial agent combinations) for the first time in order to prevent the colonization and biofilm formation on the surface of ureteral stents. Treating of latex rubber stents were carried out by adding the norfloxacin-metronidazole...

  3. Highly filled polymer nanocomposite films derived from novel nanostructured latexes

    OpenAIRE

    Ruggerone, Riccardo

    2010-01-01

    The overall aim of this thesis has been to assess the potential of latex-based technologies for the preparation of polymer/clay nanocomposites. The key feature of latex-based technologies is that they offer the possibility of improved control of the final nanocomposite morphology at significantly higher clay loadings than can be obtained with more conventional processing techniques, such as melt blending or in situ polymerization. The idea is to exploit swelling of the clay in either the aque...

  4. Investigating the rheological properties of native plant latex

    OpenAIRE

    Bauer, G.; Friedrich, C.; Gillig, C.; Vollrath, F.; Speck, T.; Holland, C.

    2014-01-01

    Plant latex, the source of natural rubber, has been of interest to mankind for millennia, with much of the research on its rheological (flow) properties focused towards industrial application. However, little is known regarding the rheology of the native material as produced by the plant, a key factor in determining latex's biological functions. In this study, we outline a method for rheological comparison between native latices that requires a minimum of preparatory steps. Our approach provi...

  5. Shrinkage of Latex-Modified and Microsilica Concrete Overlay Mixtures

    OpenAIRE

    Buchanan, Patricia Michelle

    2002-01-01

    Highway bridge decks are often overlaid to extend service life by reducing the rate of chloride ion ingress and the rate of corrosion of reinforcing steel in the sound chloride-contaminated concrete that is left in-place. Bridge deck overlays in Virginia are usually either latex-modified concrete or microsilica concrete, and both types of overlay are considered equivalent in terms of performance. However, the latex-modified concrete overlays are more expensive to construct than the microsil...

  6. Immune response modulation by curcumin in a latex allergy model

    Directory of Open Access Journals (Sweden)

    Raju Raghavan

    2007-01-01

    Full Text Available Abstract Background There has been a worldwide increase in allergy and asthma over the last few decades, particularly in industrially developed nations. This resulted in a renewed interest to understand the pathogenesis of allergy in recent years. The progress made in the pathogenesis of allergic disease has led to the exploration of novel alternative therapies, which include herbal medicines as well. Curcumin, present in turmeric, a frequently used spice in Asia has been shown to have anti-allergic and inflammatory potential. Methods We used a murine model of latex allergy to investigate the role of curcumin as an immunomodulator. BALB/c mice were exposed to latex allergens and developed latex allergy with a Th2 type of immune response. These animals were treated with curcumin and the immunological and inflammatory responses were evaluated. Results Animals exposed to latex showed enhanced serum IgE, latex specific IgG1, IL-4, IL-5, IL-13, eosinophils and inflammation in the lungs. Intragastric treatment of latex-sensitized mice with curcumin demonstrated a diminished Th2 response with a concurrent reduction in lung inflammation. Eosinophilia in curcumin-treated mice was markedly reduced, co-stimulatory molecule expression (CD80, CD86, and OX40L on antigen-presenting cells was decreased, and expression of MMP-9, OAT, and TSLP genes was also attenuated. Conclusion These results suggest that curcumin has potential therapeutic value for controlling allergic responses resulting from exposure to allergens.

  7. Properties of Polyacrylate Latex Prepared Under Different Emulsified Systems

    Institute of Scientific and Technical Information of China (English)

    CHEN Lijun; WU Fengqin

    2012-01-01

    The polyacrylate latexes were synthesized via pre-emulsified and semi-continuous seeded emulsion polymerization technology when conventional surfactant or polymerizable surfactant was used as emulsifiers.The resultant latexes and their films were characterized with the contact angle determinator and rheometer.Effect of the polymerizable surfactant on water resistance,stability and rheology of the latex was studied.Results show that the water resistance of film is increased first then decreased with the increase of the amount of the polymerizable surfactant.There exists the optimum value of the amount of the polymerizable surfactant for the water resistance of the film.In comparison with the latex prepared with the conventional surfactant,both the mechanical stability and the freezing-thaw stability of the latex are improved when the polymerizable surfactant is used during the course of the emulsion polymerization.The resultant latex has rheological properties of pseudo-plastic fluid and belongs to non-Newtonian fluid.

  8. Troubleshooting for the observed problems in processing latex concentrate from natural resource

    International Nuclear Information System (INIS)

    Natural latex has special importance in the rubber industry for manufacturing different types of goods like gloves, balloons, male contraceptive and similar thin walled articles. This natural latex is much more sensitive a liquid to handle since it can easily become contaminated and thereby coagulated which makes it unfavourable for centrifuge and getting concentrate from it. Some other related measures also are included in consideration during the processing of concentrate latex from the natural raw latex. The problems that are being faced in a concentrate latex processing plant can be categorized in different groups like, problems related to the latex property, mechanical problems, electrical problems, handling and storage problems, transformation problems, problems related to environmental issues, etc. Among them, the most common and vital problems frequently observed in a concentrate latex processing plant are discussed here with a view to finding the measures for solution which will help to maintain the latex property in any latex processing plant.

  9. Troubleshooting for the observed problems in processing latex concentrate from natural resource

    Science.gov (United States)

    Afreen, S.; Haque, K. R.; Huda, M. K.

    2013-06-01

    Natural latex has special importance in the rubber industry for manufacturing different types of goods like gloves, balloons, male contraceptive and similar thin walled articles. This natural latex is much more sensitive a liquid to handle since it can easily become contaminated and thereby coagulated which makes it unfavourable for centrifuge and getting concentrate from it. Some other related measures also are included in consideration during the processing of concentrate latex from the natural raw latex. The problems that are being faced in a concentrate latex processing plant can be categorized in different groups like, problems related to the latex property, mechanical problems, electrical problems, handling and storage problems, transformation problems, problems related to environmental issues, etc. Among them, the most common and vital problems frequently observed in a concentrate latex processing plant are discussed here with a view to finding the measures for solution which will help to maintain the latex property in any latex processing plant.

  10. MeV particles in a decay chain process from laser-induced processes in ultra-dense deuterium D(0)

    Science.gov (United States)

    Holmlid, Leif

    2015-04-01

    The ejection of particles with energy up to 20 MeV u-1 was reported previously from laser-induced processes in ultra-dense deuterium D(0). Studies of the kinetics of particle formation and decay, and of particle penetration through thick plates are now reported. Magnetic deflection is used to remove charged particles like electrons formed at the target. The signals at a collector in the beam at 0.9 m distance and a shadowed loop collector behind a 1.5-4.5 mm thick steel plate at 0.6 m are compared. The signal at the distant collector matches an intermediate particle B in a decay chain A → B → C with formation and decay time constants of 5-15 ns. The signal at the loop collector is delayed relative to the more distant collector, thus showing a delay of the particles penetrating through the steel plate. The signal at this collector is due to pair production with charge cancellation. Compton electrons from gamma radiation are observed at peak current densities of 1 mA cm-2 at the distant collector.

  11. MeV particles in a decay chain process from laser-induced processes in ultra-dense deuterium D(0)

    International Nuclear Information System (INIS)

    The ejection of particles with energy up to 20 MeV u-1 was reported previously from laser-induced processes in ultra-dense deuterium D(0). Studies of the kinetics of particle formation and decay, and of particle penetration through thick plates are now reported. Magnetic deflection is used to remove charged particles like electrons formed at the target. The signals at a collector in the beam at 0.9 m distance and a shadowed loop collector behind a 1.5–4.5 mm thick steel plate at 0.6 m are compared. The signal at the distant collector matches an intermediate particle B in a decay chain A → B → C with formation and decay time constants of 5–15 ns. The signal at the loop collector is delayed relative to the more distant collector, thus showing a delay of the particles penetrating through the steel plate. The signal at this collector is due to pair production with charge cancellation. Compton electrons from gamma radiation are observed at peak current densities of 1 mA cm-2 at the distant collector. (author)

  12. Latex elastomer with a permanently hydrophilic surface

    Science.gov (United States)

    Noda, Isao

    1991-03-01

    WATER wettability is important in many applications of polymeric materials, including fabrics, printing and biomedical uses1,2. Various surface-modification techniques are available to convert the intrinsically hydrophobic surfaces of plastic to water-wettable ones, by incorporating chemically polar functional groups at the surface4-7. Although such chemically induced surface hydrophilicity can be relatively long-lived while the substrates remain rigid, increases in the mobility of surface molecules, for example, due to increasing temperature, can cause rapid loss of hydrophilicity, driven by the tendency of surfaces to minimize their free energy2-5. As the polar groups are not often bound to the polymer matrix (usually being instead free surfactant molecules), they may also be flushed from the surface by repeated exposure to water. Here I report the preparation of permanently water-wettable elastomeric films from a latex synthesized by polymerization of monomers in the presence of an amphiphilic block copolymer. By migration of the hydrophilic segments to the surface during film formation, the film is rendered essentially completely wettable by water. Applications may include flexible coatings that can introduce spatially selective wettability to solid surfaces, for example one-side wettable perforated films used for bandages and disposable diapers8.

  13. Latex medical gloves: time for a reappraisal.

    Science.gov (United States)

    Palosuo, Timo; Antoniadou, Irini; Gottrup, Finn; Phillips, Peter

    2011-01-01

    Many hospitals have implemented policies to restrict or ban the use of devices made of natural rubber latex (NRL) in healthcare as precautionary measures against the perceived risk of NRL allergy. Changes in glove technology, progress in measuring the specific allergenic potential of gloves and a dramatic decrease in the prevalence of NRL allergies after interventions and education prompted us to revisit the basis for justifiable glove selection policies. The published Anglophone literature from 1990 to 2010 was reviewed for original articles and reviews dealing with the barrier and performance properties of NRL and synthetic gloves and the role of glove powder. The review shows that NRL medical gloves, when compared with synthetic gloves, tend to be stronger, more flexible and better accepted by clinicians. The introduction of powder-free gloves has been associated with reductions in protein content and associated allergies. Recently, new methods to quantify clinically relevant NRL allergens have enabled the identification of gloves with low allergenic potential. The use of low-protein, low-allergenic, powder-free gloves is associated with a significant decrease in the prevalence of type I allergic reactions to NRL among healthcare workers. Given the excellent barrier properties and operating characteristics, dramatically reduced incidences of allergic reactions, availability of specific tests for selection of low-allergen gloves, competitive costs and low environmental impact, the use of NRL gloves within the hospital environment warrants reappraisal. PMID:21720169

  14. Sensitisation to natural rubber latex: an epidemiological study of workers exposed during tapping and glove manufacture in Thailand

    OpenAIRE

    CHAIEAR, N.; Sadhra, S; Jones, M.; Cullinan, P.; Foulds, I.; BURGE, P

    2001-01-01

    OBJECTIVES—To estimate the prevalence of sensitisation to natural rubber latex in latex tappers and latex glove factory workers, and to relate this to airborne exposure to latex.
METHODS—Five hundred workers employed in three latex glove factories, 314 tappers, and 144 college students (control group) were studied. The workers in the glove factories were classified into three exposure groups; high, moderate, and low. Personal exposures to natural rubber latex aeroallergens were measured by im...

  15. 有机无机杂化物作乳化剂的苯丙乳液制备及其性能表征%Synthesis and Characterization of Poly(St-co-BA) Latex with an Organic-Inorganic Hybrid Compound as Emulsifier

    Institute of Scientific and Technical Information of China (English)

    袁俊杰; 周树学; 廖建和; 武利民

    2003-01-01

    A poly (St-co-BA) latex was successfully synthesized by using an organic-inorganic hybrid compound(OIHC), an aliphatic carboxylate sodium/nano-silica composite, as the emulsifier, and investigated by particlesize analyzer, transmission electron microscope (TEM), optical contact angle measurement (OCA) and dynamicmechanical analyzer (DMA). It was found that the protective agent, sodium polyacrylate (PA),could obviouslyimprove the polymerization stability and the functional monomer, glycidyl methacrylate (GMA), could enhancethe store stability of the latex. The particle size of poly(St-co-BA) latex decreased and then leveled off as OIHCcontent increased. TEM shows that the prepared polymers were actually organic-inorganic nanocomposites, andthese films have better waterproof property than those prepared by traditional poly(St-co-BA) latex or organicsilicone modified poly(St-co-BA) latex. The nanocomposite polymer has much higher glass transition temperaturethan organic silicone modified poly(St-co-BA) polymer containing the same organic silicone content.

  16. RAFT-Mediated Polymerization-Induced Self-Assembly of Poly(Acrylic Acid-b-Poly(Hexafluorobutyl Acrylate: Effect of the pH on the Synthesis of Self-Stabilized Particles

    Directory of Open Access Journals (Sweden)

    Jianhua Zhou

    2016-05-01

    Full Text Available This paper describes a very simple strategy towards self-stabilized poly(acrylic acid-block-poly(hexafluorobutyl acrylate (PAA-b-PHFBA block copolymer particles via reversible addition-fragmentation chain transfer (RAFT-mediated polymerization-induced self-assembly. Hexafluorobutyl acrylate (HFBA monomer conversion and number-average molar mass of PAA-b-PHFBA increased gradually with the increase in the pH value of the aqueous phase. When pH < 10, the molecular weight distributions of PAA-b-PHFBA were narrow, however, when the pH was raised to 11.55, PAA-b-PHFBA block copolymers had a broader distribution (ĐM = 1.82 with a serious trailing toward the low molecular weight. Furthermore, the morphology and size of PAA-b-PHFBA latex particles were measured by transmission electron microscopy and dynamic light scattering. The results indicated that the PAA-b-PHFBA latex particles had a clear spherical core-shell structure and the latex particles’ size increased with the increase of pH value.

  17. Prevalence of type I allergy to natural rubber latex and type IV allergy to latex and rubber additives in operating room staff with glove-related symptoms.

    Science.gov (United States)

    Miri, Sara; Pourpak, Zahra; Zarinara, Alireza; Zarinara, Alam; Heidarzade, Marzieh; Kazemnejad, Anoushirvan; Kardar, Gholamali; Firooz, Alireza; Moin, Athar

    2007-01-01

    There is lack of data on the prevalence of latex allergy in the health care setting in Iran. This study was performed to determine the prevalence of type I latex allergy and type IV allergy to latex and rubber additives among the operating room staff with glove-related symptoms in 13 general hospitals in Tehran. Skin-prick tests with commercial latex extract, patch tests with latex and 25 rubber additive series, and total and latex-specific IgE detection were performed on the operating room staff who reported latex glove-related symptoms. Five hundred twelve self-administered questionnaires (100%) were completed by all operating room staff and latex glove-related symptoms were reported by 59 (11.5%) employees. Among all symptomatic operating room staff tested, the prevalence of type I latex allergy was 30.5% and the prevalence rates of type IV allergy to latex and rubber additives were 16.7 and 14.6%, respectively. The most positive patch test result with rubber additives was related to tetramethylthiuram monosulfide (38.5%). The risk factors for type I latex allergy were female sex (p = 0.009) and positive patch test with rubber additives (p = 0.012). Subjects who had positive patch test with latex were significantly more likely to have positive patch test with rubber additives (p rubber additives. Based on this study, we recommend eliminating powdered latex gloves from the operating rooms of the 13 studied general hospitals and support the substitution of powder-free latex gloves. PMID:18034975

  18. Thermal-kinetic study of natural rubber latex films vulcanized by using gamma radiation; Estudo termo-cinetico de filmes de latex de borracha natural de Hevea brasiliensis vulcanizada por radiacao gama

    Energy Technology Data Exchange (ETDEWEB)

    Leal, Ana Paula Pinho Rodrigues; Barros, Glaucione Gomes de [Brasilia Univ., DF (Brazil). Inst. de Quimica; Guedes, Selma M.L. [Instituto de Pesquisa em Energia Nuclear, Sao Paulo, SP (Brazil)

    1999-07-01

    Vulcanization of natural rubber latex by ionization radiation produces the crosslink in disperse latex particles. Advantages over conventional process of vulcanization are: the absence of carcinogenic nitrosamines, low cytotoxicity and better degradation at room conditions, due to mainly to the absence of sulfur, zinc oxide and dithiocarbamates. Thermogravimetric analysis (TG) is the measurement of the weight change of a material as a function of temperature and time. TG data different heat speed provide an alternative model of the kinetics of degradation of polymeric materials. The kinetic studies of this material showed a single degradation process at least for 76,5% of mass loss. The activation energy was 49 Kcal/mol. For higher mass loss (85%) the degradation was characterized by associate mechanism. (author)

  19. Development of surgical gloves from radiation vulcanized natural rubber latex

    International Nuclear Information System (INIS)

    Natural rubber latex (55% DRC) containing 3 phr of CCl4 was irradiation γ-rays from Co-60 source at a dose rate of 7.5 kGy/h. Specifications of irradiated latex and mechanical properties of the radiation vulcanized latex were studied. The maximum tensile strength which was obtained at 25 kGy was 240 kg/cm2. The viscosity of the irradiated latex kept constant value under 30 kGy. The G value for crosslinking calculated from swelling is 17.0. Chlorine contents measured with activation analysis increased with increasing irradiation dose. 400 kg of latex was vulcanized at 25 kGy and used for production of rubber gloves in an existing factory with coagulant dipping process. The physical properties of the rubber gloves were as follows: tensile strength; 220-250 kg/cm2, elongation at break; 950%, permanent set; 5-10%, aging residual tensile strength after at 70degC for 72 hours; 70-80%. The gloves were accepted for domestic use as surgical and examination gloves. (author)

  20. Extractable proteins from irradiated field natural rubber latex

    International Nuclear Information System (INIS)

    Complete text of publication follows. Natural rubber latex (NRL) is extracted from Hevea brasiliensis tree and is used to produce different kinds of rubber goods like gloves, condoms, balloons and some part of medical and dental equipments, but it is predominantly used in the production of surgical and examination gloves. The allergy caused by latex products has become a serious problem; the sweat can remove proteins and allow contact with skin causing sensitization or allergic reactions. Some methods have been suggested to reduce the extractable protein content in latex gloves, as using low protein latex; proper leaching during the process of production etc. In this study field natural rubber latex was irradiated in different doses in a 60Co to reduce the water-soluble protein content in the final product. The protein content of the films obtained by casting method was extracted with phosphate buffer solution, pH 7 and was measured using Micro BCA Protein Assay kit. Also was measured protein in the serum samples of field NRL. The concentration of extractable proteins increased with increasing radiation dose

  1. Particle lithography with vapor deposition of organosilanes: A molecular toolkit for studying confined surface reactions in nanoscale liquid volumes

    International Nuclear Information System (INIS)

    Combining particle lithography with molecular self-assembly provides a practical approach for producing 2D arrays of organosilane nanostructures with well-defined geometries and designated surface coverage. By combining heated chemical vapor deposition with particle lithography, the binding of organosilanes on substrates is narrowly confined to the locations of water residues surrounding the base of latex spheres. Localized meniscus sites of water designate specific locations for the hydrolysis and condensation reactions of organosilanes. With particle lithography, billions of regular nanopatterns can be generated with high throughput to provide exquisite nanoscale control of the geometry, density and surface coverage of organosilane nanostructures. In this report, examples of organosilane nanopatterns presenting different terminal groups and chain lengths are demonstrated with atomic force microscopy images. The effect of the terminal moieties of organosilanes was investigated for nanostructures prepared by particle lithography by evaluating parameters of the number density, surface coverage and thickness of layers formed.

  2. PEGylation of Phytantriol-Based Lyotropic Liquid Crystalline Particles-The Effect of Lipid Composition, PEG Chain Length, and Temperature on the Internal Nanostructure

    DEFF Research Database (Denmark)

    Nilsson, Christa; Ostergaard, Jesper; Larsen, Susan Weng;

    2014-01-01

    Poly(ethylene glycol)-grafted 1,2-distearoyl-sn-glycero-3-phosphoethanolamines (DSPE-mPEGs) are a family of amphiphilic lipopolymers attractive in formulating injectable long-circulating nanoparticulate drug formulations. In addition to long circulating liposomes, there is an interest in developing...... injectable long-circulating drug nanocarriers based on cubosomes and hexosomes by shielding and coating the dispersed particles enveloping well-defined internal nonlamellar liquid crystalline nanostructures with hydrophilic PEG segments. The present study attempts to shed light on the possible PEGylation of...... these lipidic nonlamellar liquid crystalline particles by using DSPE-mPEGs with three different block lengths of the hydrophilic PEG segment. The effects of lipid composition, PEG chain length, and temperature on the morphology and internal nanostructure of these self-assembled lipidic aqueous...

  3. Radiation processing of natural rubber latex

    International Nuclear Information System (INIS)

    Significant progress has been made in the last 5 years in developing new rubber material using radiation technology that holds important benefits for industries in Southeast Asia and the Pacific. A driving force behind its development has been co-ordinated research through an international programme of the IAEA and United Nations Development Programme (UNDP) known as the Regional Co-operative Agreement (RCA). The technology is called radiation vulcanization of natural rubber latex, or RVNRL. It uses high-energy gamma radiation (it also can use electron beams) to initiate vulcanization, a process that chemically bonds molecules to produce rubber elasticity and strength. As with other radiation industrial processes, products are not radioactive. In the RVNRL process, radiation energy replaces the use of a sulphur-based process and produces a material that retains all properties of the conventional product. However, it has some additional remarkable qualities: the absence of carcinogenic nitrosoamines; extremely low cytotoxicity; absence of sulphur and zinc oxide; and high transparency and softness. Rubber products for medical and hygienic uses are obviously the most promising applications of RVNRL technology because of the absence of carcinogenic and toxic products. These essential requirements are easily met by the radiation technology, and at the moment, by no other alternative. Within the technology development programme, test production of various products such as condoms, gloves, nipples, pacifiers, and toy balloons are now being carried out at different centers participating in the programme. Pilot production of condoms and gloves for medical examinations is done in Indonesia. Products are tested extensively in various field locations. Low-cost irradiators have been specifically designed for vulcanization applications, and the main parameters for estimating production costs and for conducting feasibility studies have been developed

  4. THE PREVALENCE OF LATEX GLOVES – RELATED COMPLAINTS AMONG DENTAL STUDENT

    OpenAIRE

    Iliyana Stoeva

    2011-01-01

    Latex gloves are a frequent cause of complaints in dental staff, which complaints may start during the student education.The aim of the present study was to evaluate the prevalence of latex gloves-related complaints among dental students and to establish the etiology of these problems.Material and Methods: 122 dental students completed a questionnaire. Those with latex glove-related complaints were evaluated for latex sensitivity by assessment of skin prick test and for cell-mediated sensitiv...

  5. Synthesis and Characterization of Core-Shell Acrylate Based Latex and Study of Its Reactive Blends

    OpenAIRE

    Ying Nie; Min-Feng Tang; Xiao-Dong Fan; Xiang Liu

    2008-01-01

    Techniques in resin blending are simple and efficient method for improving the properties of polymers, and have been used widely in polymer modification field. However, polymer latex blends such as the combination of latexes, especially the latexes with water-soluble polymers, were rarely reported. Here, we report a core-shell composite latex synthesized using methyl methacrylate (MMA), butyl acrylate (BA), 2-ethylhexyl acrylate (EHA) and glycidyl methacrylate (GMA) as monomers and ammonium p...

  6. Fabrication of Rice Husk-Latex Composites with Cement and Fly Ash as Fillers

    International Nuclear Information System (INIS)

    Research on fabrication of rice husk composites has been done using latex as adhesive and cement and fly ash as fillers. Composite was prepared by mixing of dry rice husk (40 - 80 mesh), irradiated latex, waste latex, cement and fly ash. Composition of the mixtures were set by varying the cement content at the level of 0, 6, 8, 10 and 12 % by weight of the mixture. The mixture were pressed using press machine at 60 kg/cm2, temperature of 160oC for 15 minutes. Physical and Mechanical properties measured water contents, density and swelling ratio, modulus of rapture (MOR), modulus of elasticity (MOE), internal bond (IB), screw withdrawal (SW). Experimental results showed that water contents, density and swelling ratio were 4.05 - 5.02 %, 0.95-0.97 g/cm3 and 6.50 - 9.06 % (immersing in water for 2 hours), 9.32 - 12.44 % (immersing in water for 24 hours). According to National Industry Standard (SNI) the maximum water contents of particle board is 14 %, density is 0.50 - 0.70 g/cm3 and for swelling ratio after immersing in water should be 10 - 20 %. MOR of composites were 292.92 - 349.54 kg/cm2 (SNI : minimum 100 kg/cm2), where as MOE= 14,819 - 20,238 kg/cm2, IB and SW were 4.88 - 25.87 kg/cm2, 70 - 88 kg respectively. SW meet the SNI because the minimum value is 40 kg. (author)

  7. Introdução ao LaTeX

    Directory of Open Access Journals (Sweden)

    Eric Batista Ferreira

    2012-12-01

    Full Text Available O pacote de macros para o processamento de textos, LaTeX{}, que utiliza o TeX{} como principal ferramenta, é fundamental para a produção de textos matemáticos e científicos de alto nível e emph{layout} profissional. A necessidade de conhecê-los se torna ainda mais real para profissionais e estudantes das Ciências Exatas. Além de adequado para a notação Matemática, o LaTeX{} tem muitas outras vantagens, como ser gratuito, multiplataforma e livre de vírus. Por esses e outros motivos, o minicurso ``Introdução ao LaTeX{}'' foi ministrado na emph{I Semana da Matemática da Unifal-MG}, a convite de sua comissão organizadora.

  8. Characterization of a detector chain using a FPGA-based time-to-digital converter to reconstruct the three-dimensional coordinates of single particles at high flux

    Energy Technology Data Exchange (ETDEWEB)

    Nogrette, F.; Chang, R.; Bouton, Q.; Westbrook, C. I.; Clément, D. [Laboratoire Charles Fabry, Institut d’Optique Graduate School, CNRS, Univ. Paris-Saclay, 91127 Palaiseau cedex (France); Heurteau, D.; Sellem, R. [Fédération de Recherche LUMAT (DTPI), CNRS, Univ. Paris-Sud, Institut d’Optique Graduate School, Univ. Paris-Saclay, F-91405 Orsay (France)

    2015-11-15

    We report on the development of a novel FPGA-based time-to-digital converter and its implementation in a detection chain that records the coordinates of single particles along three dimensions. The detector is composed of micro-channel plates mounted on top of a cross delay line and connected to fast electronics. We demonstrate continuous recording of the timing signals from the cross delay line at rates up to 4.1 × 10{sup 6} s{sup −1} and three-dimensional reconstruction of the coordinates up to 3.2 × 10{sup 6} particles per second. From the imaging of a calibrated structure we measure the in-plane resolution of the detector to be 140(20) μm at a flux of 3 × 10{sup 5} particles per second. In addition, we analyze a method to estimate the resolution without placing any structure under vacuum, a significant practical improvement. While we use UV photons here, the results of this work apply to the detection of other kinds of particles.

  9. Characterization of a detector chain using a FPGA-based time-to-digital converter to reconstruct the three-dimensional coordinates of single particles at high flux

    Science.gov (United States)

    Nogrette, F.; Heurteau, D.; Chang, R.; Bouton, Q.; Westbrook, C. I.; Sellem, R.; Clément, D.

    2015-11-01

    We report on the development of a novel FPGA-based time-to-digital converter and its implementation in a detection chain that records the coordinates of single particles along three dimensions. The detector is composed of micro-channel plates mounted on top of a cross delay line and connected to fast electronics. We demonstrate continuous recording of the timing signals from the cross delay line at rates up to 4.1 × 106 s-1 and three-dimensional reconstruction of the coordinates up to 3.2 × 106 particles per second. From the imaging of a calibrated structure we measure the in-plane resolution of the detector to be 140(20) μm at a flux of 3 × 105 particles per second. In addition, we analyze a method to estimate the resolution without placing any structure under vacuum, a significant practical improvement. While we use UV photons here, the results of this work apply to the detection of other kinds of particles.

  10. Molecular detection of Papaya meleira virus in the latex of Carica papaya by RT-PCR

    NARCIS (Netherlands)

    Araujo, de M.M.M.; Tavares, E.T.; Silva, da F.R.; Marinho, V.L.D.; Souza, M.T.

    2007-01-01

    A RT-PCR assay was developed for early and accurate detection of Papaya meleira virus (PMeV) in the latex from infected papayas. The meleira disease is characterized by an excessive exudation of more fluidic latex from fruits, leaves and stems. This latex oxidises and gives the fruit a ¿sticky¿ text

  11. Reduction of residual n-butylacrylate sensitizer in radiation vulcanized natural rubber latex

    International Nuclear Information System (INIS)

    Radiation vulcanisation of natural rubber latex needs n-butyl acrylate (n-BA) to lessen required irradiation dose. Considerable amount of n-BA remains in the latex after the completion of radiation vulcanisation and tends to pollute the working environment in a dipping factory. A study has been carried out to reduce the residual n-BA after the radiation vulcanization. About 40% of added n-BA was found in the latex after irradiation to 20 kGy. Hydrolysis of n-BA was effective for reduction of the residual n-BA in the latex. No n-BA was found in the latex when the latex was stored for 4 weeks at room temperature due to its hydrolysis. Heating of the latex was effective to accelerate the rate of hydrolysis of n-BA. Almost all of n-BA in the latex was hydrolysed when the latex was heated for 4 hours at 800 degree C. Tensile strength of the latex films slightly decreased by heating treatment of the latex, but gradually recovered as storage time extended. Low viscosity was attained by the heat treatment of the latex

  12. Evolving stresses in latex films as a function of temperature.

    Science.gov (United States)

    Yow, Huai Nyin; Beristain, Itxaso; Goikoetxea, Monika; Barandiaran, Maria J; Routh, Alexander F

    2010-05-01

    Latex films were dried on a flexible substrate, and the substrate deflection was monitored over time to give an averaged film stress-evolution profile. Films were dried at various temperatures below and above the minimum film-formation temperature of the latex dispersion. The effect of polymer rheology, which is a temperature-dependent parameter, on film formation, was investigated. The reliability of the Stoney model in predicting film stress from substrate curvature was also examined and compared to the Euler-Bernoulli model. It was shown that the linearized Stoney model was unsuitable for the larger measured stresses. PMID:20387802

  13. DEFORMATION OF SOFT COLLOIDAL CRYSTALLINE STRUCTURE-THEORETICAL CONSIDERATIONS AND EXPERIMENTAL EVIDENCES BY SYNCHROTRON SMALL-ANGLE X-RAY SCATTERING ON TENSILE STRETCHED POLYMERIC LATEX FILM

    Institute of Scientific and Technical Information of China (English)

    Jian-qi Zhang; Yong-feng Men

    2009-01-01

    Films obtained via drying a polymeric latex dispersion are normally colloidal crystalline where latex particles are packed into a face centered cubic (fcc) structure.Different from conventional atomic crystallites or hard sphere colloidal crystallites,the crystalline structure of these films is normally deformable due to the low glass transition temperature of the latex particles.Upon tensile deformation,depending on the drawing direction with respect to the normal of specific crystallographic plane,one observes different crystalline structural changes.Three typical situations where crystallographic c-axis,body diagonal or face diagonal of the fcc structure of the colloidal crystallites being parallel to the stretching direction were investigated.Tilting angle and d-spacing of several crystallographic planes as a function of draw ratio at each situation were derived.Experimental evidences for such relationships were also given by considering in-situ synchrotron small angle X-ray scattering data of a typical latex film during stretching.It turns out that the experimental results are fully in accordance with the mathematical calculations.

  14. Better nirodhs now from Hindustan latex Ltd.

    Science.gov (United States)

    1983-01-26

    On April 5, 1969, Hindustan Latex Limited (HLL), a Public Sector Enterprise under the Ministry of Health and Family Welfare of the Government of India, was established to produce "NIRODH"--condoms--for the nation's family planning program. The 1st factory for the manufacture of the male contraceptive was created at Trivandrum in Kerala State with Japanese collaboration. The production capacity at inception was 144 million pieces; this was doubled in 1977. From inception the company has manufactured nearly 2000 million pieces. The manufacture of condoms involves 4 main stages: compounding; moulding; vulcanizing; and electronic testing and inspection (quality control). Each of these stages of development is reviewed. HLL has achieved considerable progress and growth during the past year and recorded an all time high profit of Rs. 54.76 lakhs for 1981-82. Recently, the company delcared a 5% dividend on the paid up capital to be paid by India's government. This was possible because of the excellent working results the company achieved during the last year. During 1980-81 the company produced only 105.23 pieces of condoms. In 1981-82 the company produced 265.7 million pieces agianst the target set of 240 million pieces. For the excellent working performance of last year the company paid a good performance award to its employees apart from the minimum statutory bonus. The company has set a production target of 300 million pieces of condoms during 1982-82. HLL has planned for modernization of its 14-year old existing plant and machinery and for creating a new plant with installed capacity of 300 million pieces. The new plant is expected to be set up adjacent to the existing plant. The technical team has recommended the utilization of Japanese technology, one of the most advanced process technologies in the world for the manufacture of prophylactics, incorporating maximum automation and improvements in the process machinery. The new plant is expected to produce condoms of

  15. Trypsin inactivation by latex fabricated gold nanoparticles: A new strategy towards insect control.

    Science.gov (United States)

    Patil, Chandrashekhar D; Borase, Hemant P; Suryawanshi, Rahul K; Patil, Satish V

    2016-10-01

    Before applying nanotechnologies in biomedical and environmental areas it is advised to study interactions of nanoparticles and other nanomaterials with biomacromolecule present in living system. Moreover there is scarcity of reports on interactions between nanoparticles and biomaterials. In present report a rapid, ecofriendly method of fabricating stable gold nanoparticles (AuNPs) using latex of Jatropha curcas is reported for the first time. AuNPs found to have characteristic absorption maxima centered at 540nm, multiple irregular shapes with size range from 20 to 50nm and have crystalline nature. Latex fabricated AuNPs were found to inhibit catalytic potential of trypsin (a vital enzyme responsible for digestion, insecticide resistance and in several disease conditions). The interactions between AuNPs and trypsin were analyzed by UV-vis spectrophotometry and microwave plasma-atomic emission spectrometry which suggests formation of trypsin-AuNPs complex responsible for lowering catalytic activity of trypsin. Transmission electron microscopy, Fourier transform infrared spectroscopy and particle size distribution studies further confirm complex formation between trypsin and AuNPs. Diverse interactions of metal nanoparticles with proteins such as covalent interaction, electrostatic interactions and binding to SH group of amino acid may be the reasons behind inhibition of trypsin activity. In vivo studies on serum of several vectors and agriculturally important pests supported instrumental results on AuNPs induced trypsin inhibition. This work will bring a new research direction to explore eco-friendly nanoparticle in insect control via inhibition of enzyme catalytic potential. PMID:27542740

  16. Preparation and characterization of aqueous polyurethane oil/polyacrylate latex interpenetrating polymer network

    Science.gov (United States)

    Zhou, M. M.; Ma, L. L.; Du, J.; Cao, F.; Xiao, J. J.

    2015-07-01

    A series of aqueous polyurethane oil (network I)/polyacrylate (network II) latex interpenetrating polymer networks (LIPNs) were synthesized via the technology of latex interpenetrating polymer network combined seed emulsion polymerization process. Fourier transform infrared (FTIR) spectroscopy, laser particle size distributing analyzer and universal tension machine were utilized to characterize the bulk structures and mechanical properties of LIPNs. For used as damping material, the damping performance of LIPNs were analyzed by dynamic mechanical analysis (DMA). It was found that the damping temperature region of LIPN was wider than those of aqueous polyurethane oil, the temperature region with greater tanδ changed with the TPGDA content and hard-/soft-segment mass weight ratio (mMMA/mBA) and the glass transition temperature (Tg) of the network I and network II in LIPN occurred within shift each other, even overlap with increasing mMMA/mBA value. The results show that LIPNs synthesized through the combined process have greater tanδ and wider damping temperature region, which is suitable for the use of damping coatings.

  17. Comparison of genomic and antimicrobial resistance features of latex agglutination test-positive and latex agglutination test-negative Staphylococcus aureus isolates causing bovine mastitis

    OpenAIRE

    Moser, A.; Stephan, R.; Corti, S; Johler, S.

    2013-01-01

    The dairy industry suffers massive economic losses due to staphylococcal mastitis in cattle. The Staphaureux latex agglutination test (Oxoid, Basel, Switzerland) was reported to lead to negative results in 54% of bovine Staphylococcus aureus strains, and latex-negative strains are thought to be less virulent than Staphaurex latex-positive strains. However, comparative information on virulence and resistance profiles of these 2 groups of Staph. aureus is scarce. Our objective was to associate ...

  18. Assembly of a chimeric respiratory chain from bovine heart submitochondrial particles and cytochrome bd terminal oxidase of Escherichia coli

    OpenAIRE

    Gavrikova, Eleonora V.; Grivennikova, Vera G.; Borisov, Vitaliy B.; Cecchini, Gary; Vinogradov, Andrei D.

    2009-01-01

    Cytochrome bd is a terminal quinol oxidase in Escherichia coli. Mitochondrial respiration is inhibited at cytochrome bc1 (complex III) by myxothiazol. Mixing purified cytochrome bd oxidase with myxothiazol-inhibited bovine heart submitochondrial particles (SMP) restores up to 50% of the original rotenone-sensitive NADH oxidase and succinate oxidase activities in the absence of exogenous ubiquinone analogues. Complex III bypassed respiration and is saturated at amounts of added cytochrome bd s...

  19. Characterization of a detector chain using a FPGA-based Time-to-Digital Converter to reconstruct the three-dimensional coordinates of single particles at high flux

    CERN Document Server

    Nogrette, F; Chang, R; Bouton, Q; Westbrook, C I; Sellem, R; Clément, D

    2015-01-01

    We report on the development of a novel FPGA-based Time-to-Digital Converter and its implementation in a detection chain that records the coordinates of single particles along three dimensions. The detector is composed of Micro-Channel Plates mounted on top of a cross delay line and connected to fast electronics. We demonstrate continuous recording of the timing signals from the cross delay line at rates up to 4.1x10^6 per second and three-dimensional reconstruction of the coordinates up to 2.5x10^6 particles per second. From the imaging of a calibrated structure we measure the in-plane resolution of the detector to be 140(20) um. In addition we analyze a method to measure the resolution without placing any structure under vacuum, a significant practical improvement. While we use UV photons here, the results of this work directly apply to the detection of other kinds of particles.

  20. The properties of polydimethylsiloxane/polyacrylate latex interpenetrating polymer networks synthesized by radiation-induced seeded emulsion polymerization

    International Nuclear Information System (INIS)

    Gamma-ray induced seeded emulsion polymerization of methyl methacrylate (MMA) and butyl acrylate (BA) was carried out in the presence of polydimethylsiloxane (PDMS) seed latex. A series of PDMS/PMMA and PDMS/P(MMA-co-BA) latex interpenetrating polymer networks (LIPNs) with different composition ratios were obtained. For PDMS/PMMA series, the conversion rate of MMA reached 95 % at 1 kGy. The gel fraction of PDMS/PMMA LIPNs was above 80 %. Diameters of the LIPNs particles and their distributions increased with the content of MMA. The LIPNs achieved best film forming ability at 30 wt % of MMA. Gradient core-shell morphology was observed by transmission electron microscope (TEM). For PDMS/P(MMA-co-BA) series, the conversion of monomer decreased with increasing fraction of MMA. When BA fraction was 50 wt %, PDMS/P(MMA-co-BA) LIPNs had the best film forming ability. The graft polymerization reactions between PDMS and acrylates were confirmed by Fourier transform infrared spectroscopy (FTIR). Furthermore, the damping property of the PDMS/P(MMA-co-BA) LIPNs was characterized by dynamic mechanical analysis (DMA), which showed that the damping property of the LIPNs is better than that of pure PDMS latex. (authors)

  1. Natural rubber latex: determination and interpretation of flow curves

    Directory of Open Access Journals (Sweden)

    Harrison Lourenço Corrêa

    2015-08-01

    Full Text Available AbstractAs consumers become more demanding, the importance grows of guaranteeing the quality of products. The employment of reliable testing techniques that assure the origin and characteristics of the inputs used by industry is a key factor in this respect. In the rubber processing industry, the most commonly used characterization tests include determination of the total solids and dry rubber content, mechanical stability, odor, color and presence of volatile compounds, among others. For the most part, these tests are sufficient for the latex transformation industry. However, in situations where there is a need to know the behavior of latex in reaction to the mechanical forces of machines (mixers, pumps, etc., other tests must be used. Rheological tests to determine viscoelastic data by means of plotting flow curves combined with the application of theoretical models can provide important details for characterization of different types of latex. This article presents the protocol employed by the Rheology and Image Laboratory of Rio de Janeiro State University (UERJ for the rheological study of Brazilian latex. The samples analyzed came from the state of São Paulo.

  2. STRAIN HARDENING PROPERTIES OF STEEL FIBRE REINFORCED LATEX CONCRETE COMPOSITE

    Directory of Open Access Journals (Sweden)

    V.M. Sounthararajan

    2013-04-01

    Full Text Available Steel fibre addition in concrete possesses high merits in terms of achieving homogeneity and tensile strength properties. Polymeric addition in concrete has high advantages in terms of pore fillingeffect and subsequent increase in durability index. The combined addition of steel and polymeric latex additions in concrete leads to increased strength, durability, toughness, resistance to cracking and crack propagation. Studies were conducted in the present study to analyse the properties of concrete that can be further improved with the addition of polymer styrene butadiene rubber emulsion (SBR along with steel fibres. In this research analysis, styrene-butadiene rubber (SBR latex as a polymeric admixture was used in steel fibre reinforced concrete. The effect of curing conditions on the strength gain properties of composite steel fibre latex matrix on the compressive, flexural strength, and split tensile test of polymermodified steel fibre reinforced concrete (PSFC concrete was examined. Including SBR latex at a certain % of binder in the PSFC concrete improves the bonds within the cement matrix and steel fibres (SF. This is due to the SBR films formed in the matrix. By the comparison of properties of SFC and PSFC, it can be shown that a tremendous increase in compressive strength when 4% and 8% SBR is added along with 0.75% and 1.5% SF. The increase in flexural strength was noticed and post cracking ductility is imparted to concrete.

  3. A new tetracyclic triterpene from the latex of Euphorbia nerifolia.

    Science.gov (United States)

    Mallavadhani, Uppuluri V; Satyanarayana, K V S; Mahapatra, Anita; Sudhakar, A V S

    2004-02-01

    A new tetracyclic triterpene 9,19-cyclolanost-22(22'), 24-diene-3beta-ol, named as nerifoliene (2) along with euphol (1) were isolated from the fresh latex of Euphorbia nerifolia. Their structures were elucidated on the basis of spectral (IR, 1H and 13C NMR, FAB and EI Mass) data. PMID:14974615

  4. Porosity and ion diffusivity of latex-modified cement

    International Nuclear Information System (INIS)

    Latex-modified portland cement, which would be expected to have low permeability and ion diffusivity, was studied for possible application as a solidification agent for radioactive wastes generated from nuclear power plants. In order to predict the leaching ratio of radionuclides from the cementitious waste forms, the effect of water and latex content in the fresh cement paste on total porosity and ion diffusivity of hardened paste was quantitatively estimated. Total porosity of hardened cement paste decreased with the reduction of water content in the fresh paste and it was also reduced by latex addition. This latter effect could be attributed to the latex emulsion forming a water-proof film and filling the capillary pores. Also Cs ions diffusivity, which is the ratio of the diffusion coefficient in pore water to that in bulk water, showed an exponential correlation with total porosity for both cement materials. An empirical equation, expressing ion diffusivity as a function of total porosity, was derived from the consideration that the water constrictivity in this porous medium could cause an increase of the apparent viscosity of pore water. These results suggested a possibility that the transport behavior of radionuclides through the cementitious matrix could be estimated from the mixing parameters of the original cement pastes

  5. The construction and commissioning of MINT's latex irradiator

    International Nuclear Information System (INIS)

    The construction and installation of MINT's automatic continuous latex irradiator is described. MINT cooperated with NUKEM to design the plant. Construction was done by local building consultants and local contractor. The installation of the plant includes local fabrication components and imported components. The plant is automatically controlled by a computer system. Features of plant is described

  6. New approach for papaya latex storage without virus degradation Nova metodologia de armazenamento do latex de mamão sem degradação viral

    OpenAIRE

    Silas P. Rodrigues; Andrade, Josemar S.; José A. Ventura; Fernandes, Patricia M. B.

    2009-01-01

    Papaya meleira virus (PMeV) is the causal agent of papaya (Carica papaya L.) sticky disease, which has been detected through analysis of its double-stranded RNA (dsRNA) genome from plant latex. In this work we demonstrate that PMeV dsRNA is protected during 25 days when latex is diluted in citrate buffer pH 5.0 (1:1 v/v) and maintained at -20°C. At the same temperature, some protection was observed for pure latex or latex diluted in ultra-pure water. Conversely, the dsRNA was almost completel...

  7. Alergia látex-fruta Latex-fruit allergy

    Directory of Open Access Journals (Sweden)

    Flávia Andréia MARIN

    2002-01-01

    Full Text Available O látex está sendo considerado o alergênico do ano 2000, tendo em vista que inúmeros indivíduos, principalmente profissionais da área de saúde e pacientes submetidos a várias intervenções diagnósticas e terapêuticas, estão freqüentemente expostos aos alérgenos do látex, presentes em produtos de borracha natural. As manifestações clínicas conseqüentes às reações alérgicas de hipersensibilidade imediata vão desde rinite, urticária, conjuntivite, angioedema, asma, até anafilaxia. Estudos recentes estão demonstrando que pacientes alérgicos ao látex desenvolvem concomitantemente sensibilização a certos alimentos de origem vegetal, especialmente frutas como papaia, figo, banana, abacate, kiwi, pêssego, abacaxi, melão e castanha, acreditando-se numa provável ocorrência de reações cruzadas entre os alérgenos do látex e destas frutas. Faz-se, então, uma revisão sobre a alergia ao látex, em particular sobre os grupos de risco, incluindo a presença de reatividade cruzada entre o látex e as frutas.The latex is being considered the allergenic agent of the year 2000, taking into account that several individuals, mainly health care professionals, and patients who had undergone many diagnostic and therapeutic interventions, are frequently exposed to latex allergens, which are present in natural rubber latex products. The clinical manifestations, derived from allergic reactions of immediate hypersensitivity vary from since rhinitis, conjunctivitis, urticaria, angioedema, asthma, to anaphylaxis. Recent researches are demonstrating that patients allergic to latex develop concomitantly sensitization to certain vegetable foods, especially fruits like papaya, fig, banana, avocado, kiwi, peach, pineapple, melon and chestnut, and a probable occurrence of cross reaction between allergens of latex and of these fruits is believed. A review is made about latex allergy, in particular about risk groups, including the presence of

  8. Dental surgeons with natural rubber latex allergy: a report of 20 cases.

    Science.gov (United States)

    Field, E A

    1999-02-01

    Latex allergy is becoming a major occupational health issue and dental surgeons are at risk from becoming sensitized to natural rubber latex. A study was conducted to investigate risk factors and glove-related symptoms reported by dentists with natural rubber latex allergy. Twenty dentists, who had undergone serological or dermatological testing for a Type I allergy to latex, were identified from a questionnaire survey. Risk factors investigated were: gender, years in clinical practice, exposure to latex gloves, atopic history and food allergy. The majority of dentists (75%) gave an atopic history. Glove-related adverse reactions ranged from cutaneous to systemic manifestations. All twenty dentists reported itching of the hands in response to latex gloves. One respondent was unable to continue in dental practice because of her glove-related allergies; nineteen dentists were able to continue by using synthetic, non-latex gloves. PMID:10436562

  9. THE PREVALENCE OF LATEX GLOVES – RELATED COMPLAINTS AMONG DENTAL STUDENT

    Directory of Open Access Journals (Sweden)

    Iliyana Stoeva

    2011-08-01

    Full Text Available Latex gloves are a frequent cause of complaints in dental staff, which complaints may start during the student education.The aim of the present study was to evaluate the prevalence of latex gloves-related complaints among dental students and to establish the etiology of these problems.Material and Methods: 122 dental students completed a questionnaire. Those with latex glove-related complaints were evaluated for latex sensitivity by assessment of skin prick test and for cell-mediated sensitivity to rubber additives and occupational hazards by assessment of patch test.Results: 8.2 % of dental students had skin hand complaints wearing latex gloves. 3 of them (30 % showed a positive skin prick to latex and 1 of them (10 % showed a positive patch test to rubber additives.Conclusions: Dental students are at risk to develop occupational hypersensitivity although the limited exposure to latex gloves during education.

  10. A novel arctigenin-containing latex glove prevents latex allergy by inhibiting type I/IV allergic reactions.

    Science.gov (United States)

    Wang, Yong-Xin; Xue, Dan-Ting; Liu, Meng; Zhou, Zheng-Min; Shang, Jing

    2016-03-01

    The present study aimed at developing a natural compound with anti-allergic effect and stability under latex glove manufacturing conditions and investigating whether its anti-allergic effect is maintained after its addition into the latex. The effects of nine natural compounds on growth of the RBL-2H3 cells and mouse primary spleen lymphocytes were determined using MTT assay. The compounds included glycyrrhizin, osthole, tetrandrine, tea polyphenol, catechin, arctigenin, oleanolic acid, baicalin and oxymatrine. An ELISA assay was used for the in vitro anti-type I/IV allergy screening; in this process β-hexosaminidase, histamine, and IL-4 released from RBL-2H3 cell lines and IFN-γ and IL-2 released from mouse primary spleen lymphocytes were taken as screening indices. The physical stability of eight natural compounds and the dissolubility of arctigenin, selected based on the in vitro pharnacodynamaic screening and the stability evaluation, were detected by HPLC. The in vivo pharmacodynamic confirmation of arctigenin and final latex product was evaluated with a passive cutaneous anaphylaxis (PCA) model and an allergen-specific skin response model. Nine natural compounds showed minor growth inhibition on RBL-2H3 cells and mouse primary spleen lymphocytes. Baicalin and arctigenin had the best anti-type I and IV allergic effects among the natural compounds based on the in vitro pharmacodynamic screening. Arctigenin and catechin had the best physical stability under different manufacturing conditions. Arctigenin was the selected for further evaluation and proven to have anti-type I and IV allergic effects in vivo in a dose-dependent manner. The final product of the arctigenin-containing latex glove had anti-type I and IV allergic effects in vivo which were mainly attributed to arctigenin as proved from the dissolubility results. Arctigenin showed anti-type I and IV allergic effects in vitro and in vivo, with a good stability under latex glove manufacturing conditions

  11. Microbiological sampling of the atmosphere using a latex sounding balloon

    Science.gov (United States)

    Adkins, W. P.; Bryan, N.; Christner, B. C.; Guzik, T. G.; Stewart, M. F.; Giammanco, J. R.

    2010-12-01

    The occurrence of microbes in the atmosphere has been the subject of scientific inquiry since Louis Pasteur’s time; however, data on the nature and diversity of microbial life in the upper troposphere and stratosphere is very limited. To experimentally address this, we have designed, constructed, and field-tested a lightweight, autonomous system that can sample at high altitudes using a latex sounding balloon. An important aspect of our sampling protocol is the ability to decontaminate and assess the level of background contamination during laboratory and field handling. Our approach involves the parallel decontamination and monitoring of 3 identical payloads: (i) one that remains in the laboratory, (ii) a control on the flight string, and (iii) a payload that opens and samples airborne particles in the atmosphere. Comparative analysis of various sterilization methods indicated that ethylene oxide was most effective at decreasing the concentration of DNA-containing cells, decreasing background cellular contamination by 94%. In conjunction, germicidal ultraviolet light, sodium hypochlorite, and 70% ethanol were used to decrease the concentration of microbes associated with payload surfaces. Bioaerosol collection is achieved by impact sampling on a 3.5 mm^2 retention surface covered with a thin layer of sterile silicone grease as the payload travels through the atmosphere. Initial flights have been successful in recovering viable microorganisms present in parcels of air at altitudes of 3 km to 9 km. Microscopic analysis on the collected cell assemblages implied that ~70% of the cells were potentially viable, and aerobic heterotrophic bacteria were cultured and isolated from liquid and agar-solidified culture media. Future plans include increasing the sampling altitude up to ~30 km in a series of discrete steps, maintaining our background controls and connection to lower altitude measurements. The pressure, temperature, and radiation levels in Earth’s stratosphere

  12. Polyelectrolyte assisted charge titration spectrometry: Applications to latex and oxide nanoparticles.

    Science.gov (United States)

    Mousseau, F; Vitorazi, L; Herrmann, L; Mornet, S; Berret, J-F

    2016-08-01

    The electrostatic charge density of particles is of paramount importance for the control of the dispersion stability. Conventional methods use potentiometric, conductometric or turbidity titration but require large amount of samples. Here we report a simple and cost-effective method called polyelectrolyte assisted charge titration spectrometry or PACTS. The technique takes advantage of the propensity of oppositely charged polymers and particles to assemble upon mixing, leading to aggregation or phase separation. The mixed dispersions exhibit a maximum in light scattering as a function of the volumetric ratio X, and the peak position XMax is linked to the particle charge density according to σ∼D0XMax where D0 is the particle diameter. The PACTS is successfully applied to organic latex, aluminum and silicon oxide particles of positive or negative charge using poly(diallyldimethylammonium chloride) and poly(sodium 4-styrenesulfonate). The protocol is also optimized with respect to important parameters such as pH and concentration, and to the polyelectrolyte molecular weight. The advantages of the PACTS technique are that it requires minute amounts of sample and that it is suitable to a broad variety of charged nano-objects. PMID:27153216

  13. Synthesis of fine particles of a geometrically frustrated spin-chain system Ca3Co2O6 through a pyrophoric route and its magnetic behavior

    International Nuclear Information System (INIS)

    We report the synthesis of fine particles of a well-known geometrically frustrated spin-chain compound Ca3Co2O6 through a new route, namely, a pyrophoric method employing triethanolamine (TEA) and studied the magnetic behavior of such specimens. We find that this method of synthesis yields particles made up of rods whose diameter appears to be controllable by the fraction of TEA during synthesis. It is seen that the two well-known magnetic transitions (∼24 K and ∼8 K) remains unaffected for all TEA concentrations used. The most notable finding is that the multi-step feature in the M versus magnetic-field isotherm reported for the single crystalline form tends to smoothen out gradually with decreasing rod thickness (from about 1 μm to a few hundred nm). Further, unlike for the single crystalline form known in the literature, there is no tendency for the relaxation time (τ) to remain constant at low temperatures (<10 K) and τ remains temperature dependent up to the lowest temperature measured (1.8 K) in all the specimens. These findings suggest that the multi-step magnetization anomaly in this system may be characterized by a magnetic correlation length.

  14. Latex allergy from glove powder--an unintended risk with the switch from talc to cornstarch?

    Science.gov (United States)

    Lundberg, M; Wrangsjö, K; Johansson, S G

    1997-12-01

    The present study aimed to investigate to what extent glove powders of different origins and brands bind and release latex allergens. One mineral talc and five cornstarch powders were used. The allergenic material was sap of Hevea brasiliensis. The powders were incubated together with the natural rubber latex sap, and four series of experiments were performed. The talc showed the highest tendency to bind isotope-labeled proteins. When incubated with a latex allergen solution, it reduced free allergen from 100 to 2 units/ml compared to a reduction to 70-98 units/ml for the cornstarch powders. In contrast to the nonstable binding of allergen to cornstarch, the binding to talc was irreversible. The allergen bound to talc was allergenically intact and, when incubated with serum, reduced the concentration of free IgE antibody to latex to 10% of the initial level. Mineral talc had a high capacity to bind latex allergens firmly. In contrast, cornstarch captured the latex allergen, but the binding seemed less pronounced and was unstable. The replacement of talc by cornstarch as glove-donning powder has coincided with the rapid increase in latex allergy. Mineral talc is heavy and only transiently airborne. Could this difference between talc and cornstarch in latex-allergen-binding pattern and the tendency of the latter to be airborne play an important role in the bioavailability of latex allergen and thus in the epidemic of latex sensitization. PMID:9450142

  15. Performance Analysis of Styrene Butadiene Rubber-Latex on Cement Concrete Mixes.

    Directory of Open Access Journals (Sweden)

    Er. Kapil Soni

    2014-03-01

    Full Text Available To improve the performance of concrete, polymers are mixed with concrete. It has been observed that polymer-modified concrete (PMC is more durable than conventional concrete due to superior strength and high durability. In this research, effect of Styrene-Butadiene Rubber (SBR latex on compressive strength and flexural strength of concrete has been studied and also the optimum polymer (SBR-Latex content for concrete is calculated. This research was carried out to establish the effects of polymer addition on compressive and flexural strength using concrete with mix design of constant water-cement ratio at local ambient temperature. The mixes were prepared with Styrene-Butadiene Rubber (SBR latex -cement ratio of 0 %, 5%, 10%, 15% and 20%. Slump test was conducted on fresh concrete while compressive strength and flexural strength were determined at different age. A locally available Perma-Latex is used as SBR Latex. It has been observed that SBR latex has negative effect at early age while at 28 days, the addition of SBR latex in concrete results in enhancement of compressive strength and Flexural Strength. Based on the results of this study, latex modified concrete made using Perma-Latex may be recommended to be used with various types of concrete structures. However, for the mixes rich in cement, the dosage of SBR latex needs to be adjusted to maintain required workability of concrete.

  16. Occurrence and gas/particle partitioning of short- and medium-chain chlorinated paraffins in the atmosphere of Fildes Peninsula of Antarctica

    Science.gov (United States)

    Ma, Xindong; Zhang, Haijun; Zhou, Hongqiang; Na, Guangshui; Wang, Zhen; Chen, Chen; Chen, Jingwen; Chen, Jiping

    2014-06-01

    Chlorinated paraffins (CPs) were measured in air samples at a remote air monitoring site established in Georgia King Island, Fildes Peninsula of Antarctica (Great Wall Station, China) to study the long-range atmospheric transport of these anthropogenic pollutants to the Antarctic. Gas- and particle-phase CPs were collected using polyurethane foam plugs (PUF) and glass fiber filters (GFF) respectively during summertime of 2012. The total atmospheric levels of SCCPs and MCCPs ranged from 9.6 to 20.8 pg m-3 (average: 14.9 pg m-3) and 3.7-5.2 pg m-3 (average: 4.5 pg m-3), respectively. C10 and C11 carbon chain homologues with Cl5 and Cl6 chlorine atoms predominated in SCCP formula groups both in gas- and particle-phase. Significant linear correlation was found between gas/particle partition coefficients (KP) and sub-cooled liquid vapor pressures (pL°) (R2 = 0.437, p < 0.01), as well as KP and octanol-air partition coefficients (KOA) (R2 = 0.442, p < 0.01). Absolute slope values of two regression models (0.31 and 0.39) were less than 0.6 indicating that the way of absorption into organic matter of aerosol played a more important role on atmospheric partitioning and transferring of CPs in remote Antarctic area. Both the Junge-Pankow model and the KOA-based model tended to underestimate the sorption of lower chlorinated CPs and overestimate the sorption of highly chlorinated CPs.

  17. Extractable protein of radiation vulcanized natural rubber latex

    Energy Technology Data Exchange (ETDEWEB)

    Soebianto, Y.S. [Center for Research and Development of Isotopes and Radiation Technology, BATAN, Jakarta (Indonesia); Upul, R.M. [Rubber Research Institute of Sri Lanka, Ratmalana (Sri Lanka); Makuuchi, K.; Yoshii, F.; Kume, T. [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2000-03-01

    A new method to reduce the protein level in the latex products by irradiation is reported. Water soluble protein (WSP) solution (10%) was added into radiation vulcanized NR latex (RVNRL) as much as 3 phr in three different processes: added to RVNRL, added to re-centrifuged RVNRL, and added to RVNRL followed by centrifugation. The protein content was determined by enhanced BCA method, and identified by SDS-PAGE analysis. Addition of WSP followed by centrifugation reduces EP up to the minimum protein detection, and shortens the leaching time to 20-30 min. SDS-PAGE analysis confirms the reduction of soluble protein in the serum phase, and disappearance of protein bands in the rubber extract. Protein-WSP interaction produces water soluble complex, and removed by centrifugation. The molecular weight of WSP dictates the efficiency of protein removal. (author)

  18. Extractable protein content of radiation vulcanized natural rubber latex films

    International Nuclear Information System (INIS)

    The effects of processing conditions on extractable protein content of coagulant dipped radiation vulcanized natural rubber latex films have been investigated. Drying of wet-gel of radiation vulcanized latex films even at a relatively low temperature of 70 degree C resulted in increases of extractable protein content of the films. The extractable protein content is dependent upon both the temperature and time of drying of wet-gel deposit. Wet-gel leaching of film alone is not adequate to reduce the extractable protein content of films to low levels. Combination of wet-gel leaching, post-leaching, a dip in corn starch slurry, followed by drying at a low temperature of 70 degree C reduces the extractable protein content of films to very low levels

  19. Purification and Characterization of a Proteolytic Enzyme from Fig Latex

    Institute of Scientific and Technical Information of China (English)

    HUANG Lu; QU He-zhi; ZHANG Lei; DU Shan-shan; YANG Shuo; HAO Dong-yun; WANG Xiao-ping

    2008-01-01

    Ficin is an important component of plants in Ficus family such as fig latex. It is of special significance in medicine and industry because it exhibits activity throughout a wide range of temperature and pH values. In this work,we purified a component of ficin from the latex homogeneity of Shandong fig trees, and the properties of the purified ficin were studied. The current findings revealed that heavy metal ions were able to inhibit ficin, while DTT, L-cysteine,and β-ME were found to promote ficin activity. It was also observed that the half life of ficin at 65℃ was longer than 1 h and the Michaelis constant(Km) for casein hydrolyzation was determined to be 1.56 mg/mL. Our study shows that this purified ficin is a cysteine protease.

  20. Disseminated cryptococcal lymphadenitis with negative latex agglutination test

    Institute of Scientific and Technical Information of China (English)

    XU Xiao-guang; BI Xin-ling; WU Jian-hua; XU Hong; LIAO Wan-qing

    2012-01-01

    We reported an unusual case of disseminated cryptococcal lymphadenitis in an immunocompetent host who presented with fever and lymphadenopathy,which were the only two symptoms and signs.Latex agglutination test of serum and cerebrospinal fluid (CSF) were negative,while lymph node biopsy showed Cryptococcus neoformans.A diagnosis of disseminated cryptococcal lymphadenitis was made.Then the patient was treated with amphotericin B for 15 days as initial therapy and itraconazole for 6 months as maintenance therapy respectively.The patient received re-examination per 6 months and was followed up for 2 years.Swollen lymph nodes diminished gradually,and no fever or other symptoms were found.Latex agglutination test of serum and CSF were negative throughout the follow-up period,and anti-HIV,syphilis and tuberculosis antibody were all negative.

  1. Extractable protein of radiation vulcanized natural rubber latex

    International Nuclear Information System (INIS)

    A new method to reduce the protein level in the latex products by irradiation is reported. Water soluble protein (WSP) solution (10%) was added into radiation vulcanized NR latex (RVNRL) as much as 3 phr in three different processes: added to RVNRL, added to re-centrifuged RVNRL, and added to RVNRL followed by centrifugation. The protein content was determined by enhanced BCA method, and identified by SDS-PAGE analysis. Addition of WSP followed by centrifugation reduces EP up to the minimum protein detection, and shortens the leaching time to 20-30 min. SDS-PAGE analysis confirms the reduction of soluble protein in the serum phase, and disappearance of protein bands in the rubber extract. Protein-WSP interaction produces water soluble complex, and removed by centrifugation. The molecular weight of WSP dictates the efficiency of protein removal. (author)

  2. Graphene-philic surfactants for nanocomposites in latex technology.

    Science.gov (United States)

    Mohamed, Azmi; Ardyani, Tretya; Bakar, Suriani Abu; Brown, Paul; Hollamby, Martin; Sagisaka, Masanobu; Eastoe, Julian

    2016-04-01

    Graphene is the newest member of the carbon family, and has revolutionized materials science especially in the field of polymer nanocomposites. However, agglomeration and uniform dispersion remains an Achilles' heel (even an elephant in the room), hampering the optimization of this material for practical applications. Chemical functionalization of graphene can overcome these hurdles but is often rather disruptive to the extended pi-conjugation, altering the desired physical and electronic properties. Employing surfactants as stabilizing agents in latex technology circumvents the need for chemical modification allowing for the formation of nanocomposites with retained graphene properties. This article reviews the recent progress in the use of surfactants and polymers to prepare graphene/polymer nanocomposites via latex technology. Of special interest here are surfactant structure-performance relationships, as well as background on the roles surfactant-graphene interactions for promoting stabilization. PMID:26888600

  3. Investigative methods for natural rubber latex allergy in the UK.

    Science.gov (United States)

    Lowe, J G; Green, C M; Nasser, S M

    2005-01-01

    Allergy to natural rubber latex (NRL) has become an important health issue in recent years, but little is known about how this condition is investigated by physicians in the UK. This postal questionnaire of British dermatology and allergy specialists shows substantial variation in diagnostic practice, most notably with regard to the utilization and choice of starting dose of commercial latex prick test dilutions, reliance on allergen-specific immunoglobulin E measurement, investigation of associated fruit allergy and provision of resuscitation equipment/method of consent when challenge testing. 17% of responding physicians who investigate for NRL allergy do not perform prick test or glove challenge because of the potential risk of anaphylaxis or lack of resuscitation facilities. 87% of allergy clinic specialists report no reduction in the number of patients presenting as new referrals with suspected NRL allergy. These findings suggest a need for robust guidance to achieve more consistent investigative practice by those dealing with this condition. PMID:15701123

  4. Tensile Bond Strength of Latex-Modified Bonded Concrete Overlays

    Science.gov (United States)

    Dubois, Cameron; Ramseyer, Chris

    2010-10-01

    The tensile bond strength of bonded concrete overlays was tested using the in-situ pull-off method described in ASTM C 1583 with the goal of determining whether adding latex to the mix design increases bond strength. One slab of ductile concrete (f'c > 12,000 psi) was cast with one half tined, i.e. roughened, and one half steel-troweled, i.e. smooth. The slab surface was sectioned off and overlay mixtures containing different latex contents cast in each section. Partial cores were drilled perpendicular to the surface through the overlay into the substrate. A tensile loading device applied a direct tensile load to each specimen and the load was increased until failure occurred. The tensile bond strength was then calculated for comparison between the specimens.

  5. Extractable proteins from irradiated field natural rubber latex

    Energy Technology Data Exchange (ETDEWEB)

    Rogero, S.O.; Lugao, A.B.; Yoshii, Fumio; Makuuchi, Keizo

    2003-06-01

    In this study field natural rubber latex was irradiated with different doses near a {sup 60}Co gamma source to reduce the water-soluble protein content in the final product. The protein content of the films obtained by casting method was extracted with phosphate buffer solution, pH 7 and was measured using Micro BCA Protein Assay kit. Also was measured protein in the serum samples of field NRL. The concentration of extractable proteins increased with increasing radiation dose.

  6. Extractable proteins from irradiated field natural rubber latex

    International Nuclear Information System (INIS)

    In this study field natural rubber latex was irradiated with different doses near a 60Co gamma source to reduce the water-soluble protein content in the final product. The protein content of the films obtained by casting method was extracted with phosphate buffer solution, pH 7 and was measured using Micro BCA Protein Assay kit. Also was measured protein in the serum samples of field NRL. The concentration of extractable proteins increased with increasing radiation dose

  7. Extractable proteins from irradiated field natural rubber latex

    Science.gov (United States)

    Rogero, Sizue O.; Lugão, Ademar B.; Yoshii, Fumio; Makuuchi, Keizo

    2003-06-01

    In this study field natural rubber latex was irradiated with different doses near a 60Co gamma source to reduce the water-soluble protein content in the final product. The protein content of the films obtained by casting method was extracted with phosphate buffer solution, pH 7 and was measured using Micro BCA Protein Assay kit. Also was measured protein in the serum samples of field NRL. The concentration of extractable proteins increased with increasing radiation dose.

  8. Antiplasmodial benzophenones from the trunk latex of Moronobea coccinea (Clusiaceae)

    OpenAIRE

    Marti, G; Eparvier, V.; Moretti, Christian; Susplugas, S.; Prado, S.; Grellier, P; Retailleau, P; Gueritte, F.; Litaudon, M.

    2009-01-01

    In an effort to find antimalarial drugs, a systematic in vitro evaluation on a chloroquine-resistant strain of Plasmodium falciparum (FcB1) was undertaken on sixty plant extracts collected in French Guiana. The methanol extract obtained from the latex of Moronobea coccinea exhibited a strong antiplasmodial activity (95% at 10 mu g/ml). The phytochemical investigation of this extract led to the isolation of eleven polycyclic polyprenylated acylphloroglucinols (PPAPs), from which eight showed p...

  9. Radiation vulcanised natural rubber latex (RVNRL) market and challenges

    International Nuclear Information System (INIS)

    RVNRL has the required properties and proven useful for the manufacturing of examination gloves, balloons and finger cots at industrial scale. To date only RVNRL finger cots are available in the market. Problems and challenges for the market of other products are identified. Further success in the on going research activities will be the reference for more applications of RVNRL in the relevant industry to produce natural rubber latex products of more competitive values

  10. STRAIN HARDENING PROPERTIES OF STEEL FIBRE REINFORCED LATEX CONCRETE COMPOSITE

    OpenAIRE

    V.M. Sounthararajan; Deependra Singh; Shreyansh Parakh; S. Thirumurugan; A. Sivakumar

    2013-01-01

    Steel fibre addition in concrete possesses high merits in terms of achieving homogeneity and tensile strength properties. Polymeric addition in concrete has high advantages in terms of pore fillingeffect and subsequent increase in durability index. The combined addition of steel and polymeric latex additions in concrete leads to increased strength, durability, toughness, resistance to cracking and crack propagation. Studies were conducted in the present study to analyse the properties of conc...

  11. PREVENTION OF BIOFILM FORMATION ON NORFLOXACINMETRONIDAZOLE TREATED URETERAL LATEX STENTS

    Directory of Open Access Journals (Sweden)

    B. ELAYARAJAH

    2011-01-01

    Full Text Available Biomaterial-associated bacterial infections present common and challenging complications with medical implants. The purpose of this study was to determine the antibacterial properties of latex rubber stents with integrated norfloxacin-metronidazole (synergistic antibacterial agent combinations for the first time in order to prevent the colonization and biofilm formation on the surface of ureteral stents. Treating of latex rubber stents were carried out by adding the norfloxacin-metronidazole with the fresh latex during polymerization (polymerization method. Polymerization was facilitated by adding water and formic acid to the latexantibacterialagents solution mixture. The numbers of adhered bacteria on treated and untreated stents were calculated. Difference in the number of viable bacteria adhered on the surface of treated and untreated stentswere statistically calculated using chi square testing procedure with P < 0.05 considered significant. Tests for persistence were carried out using serial plate transfer method to determine withstanding ability of antibacterial agentss in the stents. A primary skin irritation test was performed on a laboratory animal to determine thehypersensitivity reaction of antibacterial agents treated latex rubber discs. Numbers of adhered bacteria on the surface of antibacterial agents treated and untreated stents were calculated. In the polymerization method, the number of adhered bacteria on the surface of treated stents was reduced to a significant level (P<0.05.Persistence test showed the antibacterial activity of antibacterial agents treated stents till 5 days for polymerization method. In primary skin irritation test no significant erythema and edema was detected over the skin of lab animal according to the standard skin irritation scoring.

  12. The Recycling of Resorcinol Formaldehyde Latex Coated Nylon 66

    OpenAIRE

    Wroe, Sarah

    2013-01-01

    The Waste (England and Wales) Regulations encourage business to recycle their waste, as an alternative to landfill. This study has evaluated a number of processing techniques with respect to a difficult to recycle, technical textile, in order to develop recycling opportunities. Resorcinol formaldehyde latex (RFL) coated nylon 66 is a high performance fabric used as an interface to reinforce rubber products such as timing belts.The characteristics of the RFL coated woven fabric, assessed in co...

  13. Purification of papain from fresh latex of Carica papaya

    OpenAIRE

    Rubens Monti; Carmelita A. Basilio; Henrique C. Trevisan; Jonas Contiero

    2000-01-01

    In the present study we wish to report a method of crystallizing papain from fresh papaya latex which gave higher yields than previously reported. This method does not involve the use of sulphydryl reagents. The papain thus obtained is practically pure and shows a single band when submitted to electrophoresis on polyacrylamide gel, and is identical to the papain obtained by other methods. In routine enzymatic assays, specific activity was measured using Z-gly-pNP and BAEE as substrates. Papai...

  14. Radiation vulcanized natural rubber latex is not cytotoxic

    International Nuclear Information System (INIS)

    It has been reported that urethritis and/or urethral strictures caused by urinary catheters relates to cytotoxicities of their materials, and that natural rubber latex (NRL) materials often show the strong cytotoxicities. This paper reports the cytotoxicity testing method using chinese hamster V79 cultured cells, clarifies that the toxicities of NRLs vulcanized by the conventional processes are due mainly to the contents of zinc dialkyldithiocarbamates in the materials, and that the cytotoxicity of radiation vulcanized NRL (RVNRL) is very weak. (author)

  15. The criteria and the design of MINT's latex irradiator

    International Nuclear Information System (INIS)

    The demand for RVNRL is continually on the upsurge and the present irradiation technique at the present SINAGAMA plant is not sufficient and practical to meet the demand. A number of conceptual designs were evolved to design according to the requirements of cost-effective and highly efficient plant. The number of options are described. In 1994 MINT work with NUKEM to build an automatic continuous latex irradiation plant

  16. The effect of latex maturity on the absorbed dose for preparing RVNRL of optimum tensile strength

    International Nuclear Information System (INIS)

    This paper present the results of the studies on the effects of using latex of different maturity periods, between 0 to 15 weeks on gamma irradiation dose require to prepare RVNRL of optimum tensile strength. Absorbed dose to prepare RVNRL of optimum tensile strength, molecular weight between cross-links and cross-link density were found to be influenced by the maturity of the latex used in the studies. With respect to optimum tensile strength and absorbed dose, latex of about six weeks maturity was found most suitable and economical for radiation vulcanization process. Using latex either with or without added secondary preservative the optimum tensile strength was determined at an absorbed of 8 kGy. However, the optimum tensile strength of RVNRL prepared from latex contained added secondary preservative was found to be higher than the optimum tensile strength of RVNRL prepared from latex without secondary preservative

  17. Radiation vulcanization of natural rubber latex using irradiation n-butyl acrylate aqueous emulsion as sensitizer

    International Nuclear Information System (INIS)

    Natural rubber latex was vulcanized by gamma radiation with n-butyl acrylate aqueous emulsion irradiated at dose of 1.5 kGy as sensitizer. The total solid content of latex increases on the irradiation dose. The viscosity of latex on the standing time was investigated and became stable after one month of storage. The gel content of latex films increasing with irradiation dose and attained more than 94% at dose of 10 kGy. Tensile strength of films reached the values of 31MPa; 30 Mpa and 25 Mpa at vulcanization doses of 20 kGy, 15 kGy and 8 kGy for the concentrations of sensitizer 7 phr, 9 phr and 13 phr respectively. Elongation at break decreases as increasing dose. Tear strength of rubber films was from 30-40 N/mm. The tackiness of latex films decreases and smell of vulcanized latex is almost negligible. (author)

  18. Electrical Resistance and Microstructure of Latex Modified Carbon Fiber Reinforced Cement Composites

    Institute of Scientific and Technical Information of China (English)

    WEI Jian; CHENG Feng; YUAN Hudie

    2012-01-01

    The electrical resistance,flexural strength,and microstructure of carbon fiber reinforced cement composites (CFRC) were improved greatly by adding water-redispersible latex powder.The electrical resistance of CFRC was investigated by two-probe method.The input range of CFRC based strain sensors was therefore increased,whereas electrical resistance was increased and remained in the perfect range of CFRC sensors.The analysis of scanning electron microscopy indicated that elastic latex bridges and a latex layer existed among the interspaces of the adjacent cement hydration products which were responsible for the enhancement of the flexural strength and electrical resistance.The formation mechanism of the elastic latex bridges was also discussed in detail.The continuous moving of two opposite interfaces of the latex solution-air along the interspaces of the adjacent hydrated crystals or colloids was attributed to the formation of the elastic latex bridges.

  19. Effect of antioxidants on radiated vulcanization natural rubber latex

    International Nuclear Information System (INIS)

    The effect of antioxidants on the radiated vulcanization of natural rubber latex by radiation was chosen for this studies. Irradiation with gamma ray at 8 kGy of a mixture of natural rubber latex, 0.5.phr of η-butyl acrylate (η-BA), and 0.1 phr of tert.-butyl hydroperoxide (sensitizer), yielded a radiated vulcanization natural rubber latex (RVNRL). It was found that the viscosity of this product decreased but tensile strength of its films increased with the storage time of the P,VNRL. Various kinds of antioxidants were added to RVNRL, it revealed that the physical properties of the films after aging was improved, including the tensile strength which depended on the time of leaching (0-60 minutes). Vulcanox KB was the best effective antioxidant that gave the maximum tensile strength at low concentration and with a short time for leaching. One example is medical gloves prepared from RVNRL, in the presence of 0.5 phr of Vulcanox KB. After being leached with water at 50OC for 3 min., the resulting products showed different tensile strength of 21 MPa and 20 MPa before and after aging condition respectively

  20. OCULAR TOXICITY BY LATEX OF CALOTROPIS PROCERA IN RAJASTHAN

    Directory of Open Access Journals (Sweden)

    Anil

    2014-10-01

    Full Text Available AIM: 1 document the spectrum of ocular toxicity of calotropis procera, its complications, prevention and management. 2 Make aware or educate the field workers about the toxic effects of calotropis procera latex. METHODS: A retrospective study of 25 patients those presented with accidental ocular contact or injury with latex of calotropis procera in our hospital between October 2013 to September 2014 was done. Detailed history and ocular examinations like BCVA on presentation, slit lamp examination, conjunctival and corneal involvement including fluorescein staining and IOP measurement were carried out for each patient. RESULTS: All patients were presented with painless blurring of vision with burning sensations and photophobia. All eyes had conjunctival congestion and mild to severe corneal edema with descements folds. Most of the patients were male, agriculture workers and presented within 24 hours of injury.84% patients had BCVA at presentation less than or equal to 20/40.20% eyes had iridocyclitis and 12% had associated secondary glaucoma. After treatment with topical antibiotic, steroids, cycloplegics, antiglaucoma agents, hypertonic saline and tear supplements, 88% patients recovered completely within 3 to 7 days. CONCLUTIONS: Calotropis procera latex causes significant ocular morbidity which can be prevented by simple health education.

  1. Progress in radiation vulcanization of natural rubber latex

    International Nuclear Information System (INIS)

    Vulcanization dose defined as the radiation dose at which cross-linked natural rubber in latex has the maximum tensile strength can be reduced by adding carbon tetrachloride as a reaction accelerator. The radiation vulcanization of natural rubber latex was selected as one of regional projects of IAEA in 1989 and a pilot plant was built in Jakarta. The products from it were evaluated during 1983-1985, followed by IAEA decision to support the continued R and D study at Takasaki, JAERI. Various factors to improve the properties of the products have been studied. Several advantages of the process over conventional method, such as absence of N-nitrosoamines, low cytotoxicity, decomposability in the environment, transparency and softness, were confirmed. The technology has been transferred toward commercial application in Thailand, and pilot plants being set up in Indonesia, India, Malaysia and Thailand. Moreover, the process was found to be effective in reducing protein remaining in natural rubber latex products and the initial investment and irradiation cost was found to be greatly reduced by employing low energy electron accelerator. This paper reviews such progress. (S. Ohno)

  2. Extractable protein of radiation vulcanized natural rubber latex

    International Nuclear Information System (INIS)

    Protein remained in the latex products are reported to cause serious allergy. A new method to reduce the protein level in the latex products by irradiation is reported. Water soluble protein (WSP) solution (10%) was added into radiation vulcanized NR latex (RVNRL) in three different processes. The amount of WSP was 3 phr. It was only added to RVNRL (standard), added to re-centrifuged RVNRL (pre-centrifugation), and added to RVNRL followed by centrifugation (post-centrifugation). The protein content was determined by enhanced BCA method, and identified by SDS-PAGE. Extractable protein (EP) from the rubber has been reduced up to the minimum protein detection by combining WSP addition and centrifugation. Short leaching time (20-30 min.) can be achieved after the combine treatment, and SDS-PAGE confirms the reduction of soluble protein in the serum phase, and disappearance of protein bands in the rubber extract. Protein-WSP interaction produces water soluble complex, and removed by centrifugation. The efficiency of protein removal by WSP depends on its molecular weight of WSP which relates to its water solubility. (author)

  3. CDNA library from the Latex of Hevea brasiliensis

    Directory of Open Access Journals (Sweden)

    Wilaiwan Chotigeat

    2010-12-01

    Full Text Available Latex from Hevea brasiliensis contains 30-50% (w/w of natural rubber (cis-1,4-polyisoprene, the important rawmaterial for many rubber industries. We have constructed a cDNA library from the latex of H. brasiliensis to investigate theexpressed genes and molecular events in the latex. We analyzed 412 expressed sequence tags (ESTs. More than 90% of theEST clones showed homology to previously described sequences in public databases. Functional classification of the ESTsshowed that the largest category were proteins of unknown function (30.1%, 11.4% of ESTs encoded for rubber synthesisrelatedproteins (RS and 8.5% for defense or stress related proteins (DS. Those with no significant homology to knownsequences (NSH accounted for 8.7%, primary metabolism (PM and gene expression and RNA metabolism were 7.8% and6.6%, respectively. Other categories included, protein synthesis-related proteins (6.6%, chromatin and DNA metabolism(CDM 3.9%, energy metabolism (EM 3.4%, cellular transport (CT 3.2%, cell structure (CS 3.2%, signal transduction (ST2.2%, secondary metabolism (SM 1.7%, protein fate (PF 2.2%, and reproductive proteins (RP 0.7%.

  4. Extractable proteins from field radiation vulcanized natural rubber latex

    International Nuclear Information System (INIS)

    The type I allergy associated with the use of natural rubber latex (NRL) products is caused by the NRL proteins leached by the sweat or other body fluids. Makuuchi's group proposed for the first time the proteins removal by the addition of water-soluble polymers (WSP) on radiation vulcanization of natural rubber latex (RVNRL) that is a promising process under development in many countries. In this study, Brazilian field natural rubber was irradiated with a 60Co gamma source to reduce the content of WSP in the final product. WSP was used as additive to improve the extraction of protein. After irradiation the RVNRL was centrifuged to extract the WSP and proteins. The analytical methodology for protein content was based on the modified Lowry method according to ASTM D5712. Protein determination was carried out in serum of latex and in the extracts of the gloves. The concentration of extractable water-soluble proteins in serum of irradiated field NRL (NRL1), not irradiated one (NRL2); of twice centrifuged sample with polymer additive NRL (NRL3) and of the glove manufactured (NRLG) are compared with commercial glove (CG). The irradiation process increases the extractable water-soluble proteins, EP, as reported in the literature. In this study the use of polymeric additive on the bi-centrifugation process to remove protein was successful and the EP of the glove obtained in NRL3 was at around 40% of the commercial glove

  5. Effects of Euphorbia milii latex on mitogen-induced lymphocyte proliferation

    OpenAIRE

    I.F. Delgado; Paumgartten, F. J. R.

    2014-01-01

    The crude latex of "Crown-of-Thorns" (Euphorbia milii var hislopii, syn E.splendens) is a potent plant molluscicide. For this reason, toxicological studies have been performed to evaluate the health risks posed by its use in schistosomiasis control programs. The present study is part of a more comprehensive immunotoxicological evaluation of this molluscicide. Here, we investigated the effects of E. milii latex on the proliferation of human lymphocytes in vitro. Lyophilized latex of E. milii (...

  6. A comparative analysis of latex allergy in the healthy versus high-risk pediatric population.

    Science.gov (United States)

    Faust, K; Shrewsbury, C; Zaglaniczny, K; Jarrett, M

    1999-10-01

    Allergic or hypersensitivity reactions to natural latex have been reported with increasing frequency. Many specific populations have been identified as high risk for latex sensitivity. This research focused on the pediatric surgical population. Previous research had identified children with spina bifida, children requiring bowel or bladder programs, children with a history of atopy, and children with multiple surgical exposures as high risk. The purposes of this study were to identify the prevalence of latex sensitivity in the healthy pediatric population, to compare the incidence with that of an identified high-risk population, and to determine if a survey of known risk factors for latex sensitivity was predictive of positive serum latex antibody. This was a prospective, descriptive correlational study utilizing a convenience sample size of 400 pediatric patients aged 1 to 18 years, conducted at Henry Ford Hospital and Children's Hospital of Michigan. Children were identified as high or low risk from the survey results, and all had AlaSTAT latex allergy testing (Diagnostic Products Corporation, Los Angeles, Calif). The survey was not predictive for the positive serum latex antibody. The incidence of latex sensitivity was found to be greater in the high-risk group (17.3%) than in the general pediatric population (8.6%) using the chi 2 test (P = .01). Latex-reduced environments for children likely to have repeated latex exposure may decrease the risk of reaction and more importantly decrease sensitization for them. From an anesthetic standpoint, a fairly standard preoperative question is, "What are the number and types of surgeries a patient has undergone in the past?" This information can alert the healthcare worker to how much exposure the child has had and whether a latex-reduced environment might be required to avert a latex reaction. PMID:10876437

  7. Situation of wastewater treatment of natural rubber latex processing in the Southeastern region, Vietnam

    OpenAIRE

    Nguyen, Nhu Hien; Luong, Thanh Thao

    2012-01-01

    Rubber tree is one of the main plants which play an important role in the economy of Southeastern region, Vietnam. Approximately 90% of Vietnamese natural rubber latex is exported as raw products. The preliminary process of natural rubber latex discharges a large amount of wastewater to the environment. In Vietnam, there are many available technologies set up and operated for treatment wastewater of rubber latex processing. However, the effluent quality is still poor and the concentration of ...

  8. Capsular Gene Typing of Streptococcus agalactiae Compared to Serotyping by Latex Agglutination

    OpenAIRE

    Yao, K.; Poulsen, K.; Maione, D.; Rinaudo, C. D.; Baldassarri, L.; Telford, J L; Sorensen, U. B. S.; Kilian, M.

    2013-01-01

    We evaluated three different PCR-based capsular gene typing methods applied to 312 human and bovine Streptococcus agalactiae (group B Streptococcus [GBS]) isolates and compared the results to serotyping results obtained by latex agglutination. Among 281 human isolates 27% could not be typed by latex agglutination. All 312 isolates except 5 could be typed by the three PCR methods combined. Two of these methods were multiplex assays. Among the isolates that were typeable by both latex agglutina...

  9. Evaluation of the API latex conjugate reagent for serological typing of Salmonella and Shigella species.

    OpenAIRE

    Cleary, T. J.

    1984-01-01

    The serological types of Salmonella and Shigella isolates were determined by using the SerImm Sure latex conjugates (Analytab Products, Plainview, N.Y.) and the standard slide agglutination test. The Salmonella latex conjugates correctly typed 114 of the 115 Salmonella isolates found in serogroups A through F; 50% these isolates were from serogroups B. The Shigella latex conjugates correctly typed 87 of the 92 Shigella isolates; 87% of these isolates were from serogroups B and D.

  10. Secretory Duct Structure and Phytochemistry Compounds of Yellow Latex in Mangosteen Fruit

    OpenAIRE

    DORLY; SOEKISMAN TJITROSEMITO; ROEDHY POERWANTO; JULIARNI

    2008-01-01

    Yellow latex is the main problem in mangosteen agribusiness, because it is one factor lowering the fruit quality. The structure of yellow latex secretory ducts in the flower and fruit as well as in the root, stem and leaf of mangosteen (Garcinia mangostana L.) seedling and the qualitative phytochemistry of yellow latex were studied. The ducts were branched, canal-like type. They were found in the exocarp, mesocarp, endocarp, aril of the fruit, flower, stem, and leaf. In the fruit, the biggest...

  11. Histamine mediates the pro-inflammatory effect of latex of Calotropis procera in rats

    Directory of Open Access Journals (Sweden)

    Yatin M. Shivkar

    2003-01-01

    Full Text Available Introduction: Calotropis procera is known to produce contact dermatitis and the latex of this plant produces intense inflammation when injected locally. However, the precise mode of its pro-inflammatory effect is not known. In present study we have pharmacologically characterized the inflammation induced by latex of C. procera in a rat paw edema model and determined the role of histamine in latex-induced inflammation.

  12. Grand Rounds: Latex-Induced Occupational Asthma in a Surgical Pathologist

    OpenAIRE

    Green-McKenzie, Judith; Hudes, Debra

    2005-01-01

    Context: Latex allergy and sensitization have been an important problem facing health care workers. Providing a latex-safe environment is the intervention of choice. Case Presentation: A 46-year-old surgical pathologist presented with increasing shortness of breath for the previous 4 years. Twenty years before presentation, he noted a pruritic, erythematous rash on his hands, associated with latex glove use. Fourteen years before presentation, during pathology residency, he developed a nonpro...

  13. STUDY ON THE PROPERTIES OF BLEND OF NATURAL RUBBER LATEX/METHYL METHACRYLATE GRAFTED RUBBER LATEX BY GAMMA RADIATION

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Natural rubber latex (NRL) and methyl methacrylate (MMA) grafted rubber latex were blended in different ratios and irradiated at various absorbed doses by gamma rays from Co-60 source at room temperature.The tensile properties,swelling ratio and permanent set were measured.The maximum tensile strength and modulus at 500% elongation were obtained at an absorbed dose of 8 kGy.Modulus increases from 6.99 Mpa to 9.87 Mpa for an increase in proportion of MMA grafted rubber from 40% to 60% in the blend at similar absorbed dose.Elongation at break and swelling ratio decrease with increasing absorbed dose as well as the MMA grafted rubber content in the blends.The decreasing trend of permanent set is high up to 5 kGy absorbed dose, and beyond that dose,it becomes almost flat.

  14. ANTIMICROBIAL ACTIVITY AND PHYTOCHEMICAL SCREENING OF FRESH LATEX OF EUPHORBIA THYMIFOLIA LINN

    Directory of Open Access Journals (Sweden)

    Killedar Suresh Ganpati

    2011-05-01

    Full Text Available Euphorbia thymifolia Linn is small branched, pubescent, prostate annual herb with opposite oblong leaves, commonly known as laghududhika or choti-dudhi. Plant juice is employed in south India as cure for ring worms. The ethyl acetate extract and chloroform extract is reported to inhibit the growth of E. coli and Shigella flexneri. No scientific literature was found on medicinal properties of fresh latex. Hence the present work was designed to evaluate the traditional claims of Euphorbia thymifolia Linn. We have collected the fresh latex of plant by capillary action (1 kg of fresh sample gives 1.5ml of latex. The collected fresh latex was tested for antimicrobial activity by cylindrical cup plate method using standard cultures. Fresh latex showed maximum activity compare to diluted latex, dried latex, fresh juice and ethyl acetate, butanol, chloroform extracts of fresh plant. The antimicrobial activity of latex was found comparable with ciprofloxacin and fluconazole at tested concentration. The latex showed presence of tannins, resins, glycosides and sugars.

  15. Maillard Reaction in Natural Rubber Latex: Characterization and Physical Properties of Solid Natural Rubber

    OpenAIRE

    Montha, S.; P. Suwandittakul; A. Poonsrisawat; Oungeun, P.; Kongkaew, C.

    2016-01-01

    Maillard reaction in Natural Rubber (NR) latex was investigated by treating fresh NR latex with glutaraldehyde (C5H8O2) in amounts of 0, 50, 100, and 200 mmol/kg of latex. Protein cross-linking in fresh NR latex and solid NR was confirmed by using sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) and attenuated total reflection infrared (ATR-IR) spectroscopy, respectively. It was found that degree of protein cross-linking in NR increased with increasing C5H8O2 concentration....

  16. Natural Rubber Latex Hypersensitivity with Skin Prick Test in Operating Room Personnel

    Directory of Open Access Journals (Sweden)

    Seyed Hessamedin Nabavizadeh

    2009-12-01

    Full Text Available Hypersensitivity reactions to natural rubber latex have increased recently, especially among people with high exposure to latex allergens. Hypersensitivity reactions to latex are related to many conditions like occupational asthma. Our study was performed to determine the prevalence of hypersensitivity to natural rubber latex and potential food cross reactions in operation room personnel in Shiraz hospitals. In this cross-sectional, descriptive study, 580 operation room personnel filled out our questionnaire which included data about their personal history, symptoms of latex hypersensitivity, and other related allergies such as food hypersensitivity. An informed consent was obtained and skin prick tests were performed for natural rubber latex and potential food cross reactions (kiwi, banana, and potato. The obtained data were analyzed by SPSS and Chi-square test.Results: 104 (17.9% of the operating room personnel showed positive latex skin tests. We revealed a significant correlation between those with positive skin tests to latex with atopia, urthicaria, and food hypersensitivity. The prevalence did not vary by sex, age, education, surgical and non-surgical gloves users, or history of contact dermatitis. Latex hypersensitivity is common among operation room personnel. Evaluation of symptoms and prediction of future diseases necessitate screening tests in individuals at risk.

  17. Evaluation of cytotoxicity and genotoxicity of Hancornia speciosa latex in Allium cepa root model.

    Science.gov (United States)

    Ribeiro, T P; Sousa, T R; Arruda, A S; Peixoto, N; Gonçalves, P J; Almeida, L M

    2016-02-01

    The latex obtained from Hancornia speciosa Gomes (Mangabeira tree) is widely used in traditional medicine to treat a variety of diseases, including diarrhea, ulcer, gastritis, tuberculosis, acne and warts. In this study, the cytotoxicity and genotoxicity effects of H. speciosa latex on the root meristem cells of Allium cepa were examined. Onion bulbs were exposed to different concentrations of latex and then submitted to microscopic analysis using Giemsa stain. Water was used as a negative control and sodium azide as a positive control. The results showed that, under the testing conditions, the mitotic index (MI) of the onion roots submitted to latex treatment did not differ significantly from the negative control, which suggests that the latex is not cytotoxic. Low incidence of chromosome aberrations in the cells treated with H. speciosa latex was also observed, indicating that the latex does not have genotoxic effect either. The MI and the chromosome aberration frequency responded to the latex concentration, requiring more studies to evaluate the dosage effect on genotoxicity. The results indicate that in tested concentrations H. speciosa latex is probably not harmful to human health and may be potentially used in medicine. PMID:26909640

  18. Use of radiation vulcanized natural rubber latex in small and medium scale industries in Sri Lanka

    International Nuclear Information System (INIS)

    The latex based industry is fast growing with the setting up of several units to produce household and examination gloves. Production of rubberized coir using concentrated latex is also growing rapidly while more and more small scale industries have been set up. There is also a growth in the large scale sector in the dipped goods manufacture. Use of irradiated latex in the manufacture of dipped products has good potential as the efficiency of production is enhanced in the case of latex containing less additives. (author)

  19. Elements of the LaTeX system for the development of large publications

    DEFF Research Database (Denmark)

    Andersen, Esben Sloth

    This document presents gives a quick overview over the LATEX system from the viewpoint of the production of books and complex papers. Thereby it provides the starting point for the author's selection of a set of LATEX packages and the development of related commands.......This document presents gives a quick overview over the LATEX system from the viewpoint of the production of books and complex papers. Thereby it provides the starting point for the author's selection of a set of LATEX packages and the development of related commands....

  20. Purification and biochemical characterization of Eumiliin from Euphorbia milii var. hislopii latex.

    Science.gov (United States)

    Fonseca, K C; Morais, N C G; Queiroz, M R; Silva, M C; Gomes, M S; Costa, J O; Mamede, C C N; Torres, F S; Penha-Silva, N; Beletti, M E; Canabrava, H A N; Oliveira, F

    2010-05-01

    A protease, which we designate Eumiliin, was isolated from the latex of Euphorbia milii var. hislopii by a combination of ion-exchange chromatographic steps using DEAE-Sephacel and gel-filtration with Sephadex G-75. Eumiliin is a monomeric protein with an apparent molecular mass of 30 kDa by SDS-PAGE under reducing conditions and gave one main peak at 29,814 KDa in MALDI-TOF/TOF mass spectrometry. Eumiliin has caseinolytic and fibrinogenolytic activities, but no hemorrhagic or defibrinating activities. The enzyme readily hydrolyzes the Aalpha-chain of fibrinogen and, more slowly, the Bbeta-chain. Its fibrinogenolytic activity is inhibited by beta-mercaptoethanol and leupeptin. In contrast, EDTA and benzamidine did not affect the activity of Eumiliin. The caseinolytic activity of Eumiliin had a pH optimum of 8.0 and was stable in solution at up to 40 degrees C; activity was completely lost at >or=80 degrees C. Intraplantar injection of Eumiliin (1-25 microg/paw) caused a dose- and time-dependent hyperalgesia, which peaked 1-5h after enzyme injection. Intraplantar injection of Eumiliin (1-25 microg/paw) also caused an oedematogenic response that was maximal after 1h. Morphological analyses indicated that Eumiliin induced an intense myonecrosis, with visible leukocyte infiltrate and damaged muscle cells 24h after injection. PMID:20206951

  1. Long-term clearance of inhaled magnetite and polystyrene latex from the lung: a comparison

    International Nuclear Information System (INIS)

    As part of a larger study evaluating the applicability of a magnetic detection technique for monitoring lung retention of inhaled particles, simultaneous radiological measurements of the retention of magnetite and polystyrene latex particles in four donkeys were performed. The radiometric measurements were performed using a scintillation detector series modified for separation of the higher energy γ-emissions of 59Fe and 85Sr. In all animals, after 24 hr post-exposure, both polystyrene and magnetite exhibited a relatively rapid phase for 80 days (Tsub(1/2) = 15-22 days) which, in three donkeys, was clearly followed by a slower phase (Tsub(1/2) = 42-173 days); activity levels after 80 days in the fourth donkey were too low to permit determination of clearance rate. During the second phase, a deviation in pattern was clearly observed between the two aerosols, the polystyrene being cleared consistently faster than the magnetite. It is suggested that this deviation implies that, beginning at this time, there were functional differences between the dominant clearance mechanisms for the two aerosols. Exactly what these mechanisms were, or whether the difference was attributable to specific differences in particle characteristics, could not be determined. (U.K.)

  2. Latex sensitization in health care workers and in the US general population.

    Science.gov (United States)

    Garabrant, D H; Roth, H D; Parsad, R; Ying, G S; Weiss, J

    2001-03-15

    Sensitization to natural rubber latex is a prerequisite to type I immediate hypersensitivity reactions (urticaria, angioedema, anaphylaxis, and allergic rhinitis) that result from subsequent latex exposure. This study examines occupations in which latex glove use is common to determine whether it is associated with increased prevalence odds of latex sensitization (measured by latex-specific immunoglobulin E antibodies) by using data from 5,512 adults aged 17--60 years from the Third National Health and Nutrition Examination Survey (1988--1991). After other factors associated with latex sensitization were controlled for, there was a nonsignificant association between longest-held jobs in health care and latex sensitization (odds ratio (OR) = 1.49, 95 percent confidence interval (CI): 0.92, 2.40). For current occupations, latex sensitization was not associated with health care work in which gloves were used (OR = 1.17, 95 percent CI: 0.51, 2.65) or with other occupations in which latex glove use is common (OR = 1.01, 95 percent CI: 0.49, 2.07) compared with other occupations. Current health care workers who reported not using gloves were at increased risk of latex sensitization, both among those without a history of childhood atopy (OR = 2.30, 95 percent CI: 1.04, 5.13) and those with such a history (OR = 28.04, 95 percent CI: 3.64, 215.97). This odds ratio heterogeneity suggests that subjects with childhood atopy may be at high risk of latex sensitization. PMID:11257057

  3. Nitrogen removal from concentrated latex wastewater by land treatment

    Directory of Open Access Journals (Sweden)

    Vikanda Thongnuekhang

    2004-05-01

    Full Text Available Most of the concentrated latex factories in the South of Thailand discharge treated wastewater that contains high level of nitrogen to a nearby river or canals leading to a water pollution problem. A study of land treatment system was conducted to treat and utilize nitrogen in treated wastewater from the concentrated latex factory. The experimental pilot-scale land treatment system was constructed at the Faculty of Engineering, Prince of Songkla University, Hat Yai Campus. It consisted of water convolvulus (Ipomea aquatica, I. Reptans, tropical carpet grass (Axonopus compresus (Swartz Beav. and control unit (no plantation. The treated wastewater from the stabilization pond system of the selected concentrated latex factoryin Songkhla was used to irrigate each experimental unit. Influent and effluent from the experimental units were analyzed for TKN, NH3-N, Org-N, NO3 --N, NO2 --N, BOD5, sulfate, pH and EC. The land treatment system resulted a high removal efficiency for nitrogen. Tropical carpet grass provided higher removal efficiency than other units for all parameters. The removal efficiency of water convolvulus and control unit were not significantly different. The average removal efficiency of TKN, NH3-N, Org-N, BOD5 and sulfate for tropical carpet grass unit were 92, 97, 61, 88 and 52%, for water convolvulus unit were 75, 80, 43, 41 and 30%, and for control unit were 74, 80, 41, 31 and 28%, respectively. Mass balance of nitrogen transformation was conducted. It revealed that plant uptake was the major mechanism for nitrogen removal in land treatment.

  4. Characteristics of Red Algae Bioplastics/Latex Blends under Tension

    Directory of Open Access Journals (Sweden)

    M. Nizar Machmud

    2013-10-01

    Full Text Available Cassava, corn, sago and the other food crops have been commonly used as raw materials to produce green plastics. However, plastics produced from such crops cannot be tailored to fit a particular requirement due to their poor water resistance and mechanical properties. Nowadays, researchers are hence looking to get alternative raw materials from the other sustainable resources to produce plastics. Their recent published studies have reported that marine red algae, that has been already widely used as a raw material for producing biofuels, is one of the potential algae crops that can be turned into plastics. In this work, Eucheuma Cottonii, that is one of the red alga crops, was used as raw material to produce plastics by using a filtration technique. Selected latex of Artocarpus altilis and Calostropis gigantea was separately then blended with bioplastics derived from the red algae, to replace use of glycerol as plasticizer. Role of the glycerol and the selected latex on physical and mechanical properties of the red algae bioplastics obtained under a tensile test performed at room temperature are discussed. Tensile strength of some starch-based plastics collected from some recent references is also presented in this paperDoi: 10.12777/ijse.5.2.81-88 [How to cite this article: Machmud, M.N., Fahmi, R.,  Abdullah, R., and Kokarkin, C.  (2013. Characteristics of Red Algae Bioplastics/Latex Blends under Tension. International Journal of Science and Engineering, 5(2,81-88. Doi: 10.12777/ijse.5.2.81-88

  5. A Latex Metabolite Benefits Plant Fitness under Root Herbivore Attack.

    Science.gov (United States)

    Huber, Meret; Epping, Janina; Schulze Gronover, Christian; Fricke, Julia; Aziz, Zohra; Brillatz, Théo; Swyers, Michael; Köllner, Tobias G; Vogel, Heiko; Hammerbacher, Almuth; Triebwasser-Freese, Daniella; Robert, Christelle A M; Verhoeven, Koen; Preite, Veronica; Gershenzon, Jonathan; Erb, Matthias

    2016-01-01

    Plants produce large amounts of secondary metabolites in their shoots and roots and store them in specialized secretory structures. Although secondary metabolites and their secretory structures are commonly assumed to have a defensive function, evidence that they benefit plant fitness under herbivore attack is scarce, especially below ground. Here, we tested whether latex secondary metabolites produced by the common dandelion (Taraxacum officinale agg.) decrease the performance of its major native insect root herbivore, the larvae of the common cockchafer (Melolontha melolontha), and benefit plant vegetative and reproductive fitness under M. melolontha attack. Across 17 T. officinale genotypes screened by gas and liquid chromatography, latex concentrations of the sesquiterpene lactone taraxinic acid β-D-glucopyranosyl ester (TA-G) were negatively associated with M. melolontha larval growth. Adding purified TA-G to artificial diet at ecologically relevant concentrations reduced larval feeding. Silencing the germacrene A synthase ToGAS1, an enzyme that was identified to catalyze the first committed step of TA-G biosynthesis, resulted in a 90% reduction of TA-G levels and a pronounced increase in M. melolontha feeding. Transgenic, TA-G-deficient lines were preferred by M. melolontha and suffered three times more root biomass reduction than control lines. In a common garden experiment involving over 2,000 T. officinale individuals belonging to 17 different genotypes, high TA-G concentrations were associated with the maintenance of high vegetative and reproductive fitness under M. melolontha attack. Taken together, our study demonstrates that a latex secondary metabolite benefits plants under herbivore attack, a result that provides a mechanistic framework for root herbivore driven natural selection and evolution of plant defenses below ground. PMID:26731567

  6. Alternative vulcanization process of natural rubber latex induced by ionizing radiation

    International Nuclear Information System (INIS)

    The natural rubber latex was vulcanized by two different process: a) thermal process in the presence of sulfur; b) alternative process using radiation (gamma rays and electrons beam). The comparative study of rubber goods quality (surgical gloves and balloons) was carried out by physical and chemical properties of pre vulcanized latex and physical and mechanics properties of rubber goods for two process. (author)

  7. Polymer composites prepared from heat-treated starch and styrene-butadiene latex

    Science.gov (United States)

    Thermoplastic starch/latex polymer composites were prepared using styrene–butadiene (SB) latex and heat-treated cornstarch. The composites were prepared in a compression mold at 130 °C, with starch content 20%. An amylose-free cornstarch, waxy maize, was used for this research and the heat treatment...

  8. Banded cucumber beetle (Coleoptera: Chrysomelidae) resistance in romaine lettuce: understanding latex chemistry

    Science.gov (United States)

    Many plants subjected to herbivore damage exude latex, a rich source of biochemicals, which play important roles in host plant resistance. Our previous studies showed that fresh latex from Valmaine, a resistant cultivar of romaine lettuce Lactuca sativa L., applied to artificial diet is highly deter...

  9. Isotactic polypropylene/carbon nanotube composites prepared by latex technology: electrical conductivity study

    NARCIS (Netherlands)

    Grossiord, N.; Wouters, M.E.L.; Miltner, H.E.; Lu, K.; Loos, J.; Mele, B.V.; Koning, C.E.

    2010-01-01

    Several series of nanocomposites were prepared using a latex-based process, the main step of which consisted of mixing an aqueous suspension of exfoliated carbon nanotubes (CNTs) and a polymer latex. In the present work, a systematic study on the electrical properties of fully amorphous (polystyrene

  10. Latex Allergy, a Special Risk for Patients with Chronic Illness and Health Care Workers

    Directory of Open Access Journals (Sweden)

    A.Zafer Caliskaner

    2008-06-01

    Full Text Available Natural rubber latex allergy is a new illness whose prevalence has reached epidemic proportions in highly exposed populations such as health care workers and who has chronic illness. After anaphylactic type reactions due to latex has been shown as case reports. The major risk factors in latex are intense exposure to latex allergens (surgical gloves, catheters, etc, atopy, hand eczema, female gender, history of multiple operations and dental interventions. An association between latex allergy and allergy to various fruits (banana, kiwi, avocado, pineapple, etc has been reported. Latex allergy is responsible for a wide spectrum of clinical symptoms ranging from a mild dermatitis to severe anaphylaxis. In this report, we present that latex related systemic allergic reactions cases; the first one is 24 years old nurse woman who is working at the blood bank in our hospital and the other one is 32 years old woman patient who has repeatative medical examination, and in vitro fertilisation therapy plan and suffered for systemic allergic reaction due to latex gloves which was used in her last concha operations. [TAF Prev Med Bull 2008; 7(3.000: 265-268

  11. Molecular profile of sensitization in subjects with short occupational exposure to latex

    Directory of Open Access Journals (Sweden)

    Monica Lamberti

    2015-10-01

    Full Text Available Objectives: We examined the prevalence of latex allergy in subjects with occupational exposure to latex allergens for less than 5 years, determining the disease spectrum in symptomatic workers. We identified the most frequent molecular allergens by Immuno- CAP (ICAP, correlating the findings with skin prick test (SPT results. Material and Methods: Seven hundred twenty-three healthcare students using latex gloves on a regular basis were invited to participate in a baseline questionnaire screening. An ICAP serum test was performed only when a possible latex allergy was indicated by the questionnaire. Results: The total number of participants responding to the baseline survey was 619. Glove-related symptoms were indicated by 4% (N = 25 of the students. The most common symptom was contact dermatitis (N = 18, 72%. In 12 subjects, ICAP revealed a real sensitization to latex, with a recombinant latex allergen profile showing a high frequency for rHev b 6.01 specific immunoglobulin E (sIgE (N = 9, 67%. In these individuals, skin symptoms were more prevalent than other types (88%. Conclusions: The combined positivity for rHev b 6.01, rHev 8 and rHev b 5 determined by ICAP identified 92% of latex-allergic subjects with short-term exposure to latex.

  12. Prevalence of latex-specific IgE antibodies in hospital personnel

    NARCIS (Netherlands)

    Kaczmarek, RG; Silverman, BG; Gross, TP; Hamilton, RG; Kessler, E; ArrowsmithLowe, JT; Moore, RM

    1996-01-01

    Background: Rubber latex hypersensitivity is an important concern for health care workers. Purpose: The Center for Devices and Radiological Health, in collaboration with the Consumer Product Safety Commission, conducted a multicenter study of the prevalence of latex-specific IgE antibodies among Uni

  13. Latex of "Coroa de Cristo" (Euphorbia Splendens): an effective molluscicide

    OpenAIRE

    Maurício C. de Vasconcelos; Virgínia T. Schall

    1986-01-01

    An aqueous solution of the latex of "coroa de cristo" (Euphorbia splendens var. hislopii) showed molluscicide action (LD90) at a concentration lower than 0.5 ppm on Biomphalaria glabrata and B. tenagophila reared in laboratory and at a concentration lower than 4.0 ppm for field B. tenagophila.Foi estudada em laboratório a atividade moluscicida do látex da "coroa de cristo" (Euphorbia splendens var. hislopii). A planta apresentou ação moluscicida (DL90) a uma concentração inferior de 0,5ppm pa...

  14. A New Prenylated Xanthone from Latex of Garcinia cowa Roxb.

    OpenAIRE

    Zhi Na; Qishi Song; Hua b in Hu

    2013-01-01

    A new prenylated xanthone, 1,6-dihydroxy-3,7-dimethoxy-2-(3,7-dimethyloct-2,6-dienyl) xanthone (3-O-methylcowaxanthone) (1), together with four known xanthones, cowaxanthone (2), 7-O-methylgarcinone (3), α-mangostin (4) and γ-mangostin (5) were isolated from the latex of Garcinia cowa. The structure of compound 1 was elucidated on the basis of spectroscopic data interpretation, including 1D and 2D NMR and HREIMS. The cytotoxic activitiy of 1 against five human cancer cell lines, HL-60, SMMC-7...

  15. Antiplasmodial benzophenones from the trunk latex of Moronobea coccinea (Clusiaceae).

    Science.gov (United States)

    Marti, Guillaume; Eparvier, Véronique; Moretti, Christian; Susplugas, Sophie; Prado, Soizic; Grellier, Philippe; Retailleau, Pascal; Guéritte, Françoise; Litaudon, Marc

    2009-01-01

    In an effort to find antimalarial drugs, a systematic in vitro evaluation on a chloroquine-resistant strain of Plasmodium falciparum (FcB1) was undertaken on sixty plant extracts collected in French Guiana. The methanol extract obtained from the latex of Moronobea coccinea exhibited a strong antiplasmodial activity (95% at 10microg/ml). The phytochemical investigation of this extract led to the isolation of eleven polycyclic polyprenylated acylphloroglucinols (PPAPs), from which eight showed potent antiplasmodial activity with IC50 ranged from 3.3microM to 37.2microM. PMID:19054532

  16. n-butyl acrylate as a sensitizer for radiation vulcanization of natural rubber latex

    International Nuclear Information System (INIS)

    As a sensitizer for radiation vulcanization of NR latex n-butyl acrylate (n-BA) has several advantages such as high sensitizing efficiency and easiness of removal of residue by drying. However n-BA tends to destabilize NR latex. A study to stabilize NR latex against n-BA has been carried out. The most effective stabilizer is potassium hydroxide. By the addition of 0.2 phr KOH the stability of NR latex is sufficiently improved to withstand the addition of 5 phr n-BA. The sensitizing efficiency of n-BA is so high that the vulcanization dose is 15 kGy with 5 phr n-BA without the addition of carbon tetrachloride as a co-sensitizer. The radiation vulcanized NR latex has enough stability for a 90 days storage. (author)

  17. Radiation vulcanization of natural rubber latex with 3 MeV electron beams, 1

    International Nuclear Information System (INIS)

    The sensitized radiation vulcanization of natural rubber latex has been carried out with a 3 MeV, 25 mA Dynamitron electron accelerator. Latex was irradiated over a range of dose rate from 0.3 to 60 kGy/sec in the presence of sensitizers such as n-butyl acrylate, 2-ethylhexyl acrylate, and 1,6-hexanediol diacrylate. The sensitized vulcanization of NR latex with electron beams is greatly affected by dose rate. The vulcanization dose increases with increasing dose rate. The maximum tensile strength of rubber films from the irradiated latex decreases slightly with increasing dose rate. There is negligible effect of dose rate on the viscosity of the irradiated latex. (author)

  18. Research based prevention strategies. Management of latex allergy in the workplace.

    Science.gov (United States)

    Miller, K K

    2000-06-01

    1. Facility-wide goals should combine primary and secondary prevention approaches to reduce or minimize contact and aerosolized natural rubber latex exposure for clients, employees, and visitors. 2. Potential immune sensitization or continuation of symptoms of latex allergy can be reduced by using screening questionnaires to recognize potential risk factors or history of latex allergy; documentation of a referral to a physician for diagnosis; standardization of facility-wide general product selection; and work environment controls by discriminate, appropriate, informed glove choices. 3. Discriminate glove choices of nonlatex, non-powedered, or low allergen/non-powdered natural rubber latex gloves have become the primary proactive strategy adopted by hospitals and clinics to create a latex minimized environment. PMID:11249375

  19. Elucid—exploring the local universe with the reconstructed initial density field. I. Hamiltonian Markov chain Monte Carlo method with particle mesh dynamics

    International Nuclear Information System (INIS)

    Simulating the evolution of the local universe is important for studying galaxies and the intergalactic medium in a way free of cosmic variance. Here we present a method to reconstruct the initial linear density field from an input nonlinear density field, employing the Hamiltonian Markov Chain Monte Carlo (HMC) algorithm combined with Particle-mesh (PM) dynamics. The HMC+PM method is applied to cosmological simulations, and the reconstructed linear density fields are then evolved to the present day with N-body simulations. These constrained simulations accurately reproduce both the amplitudes and phases of the input simulations at various z. Using a PM model with a grid cell size of 0.75 h –1 Mpc and 40 time steps in the HMC can recover more than half of the phase information down to a scale k ∼ 0.85 h Mpc–1 at high z and to k ∼ 3.4 h Mpc–1 at z = 0, which represents a significant improvement over similar reconstruction models in the literature, and indicates that our model can reconstruct the formation histories of cosmic structures over a large dynamical range. Adopting PM models with higher spatial and temporal resolutions yields even better reconstructions, suggesting that our method is limited more by the availability of computer resource than by principle. Dynamic models of structure evolution adopted in many earlier investigations can induce non-Gaussianity in the reconstructed linear density field, which in turn can cause large systematic deviations in the predicted halo mass function. Such deviations are greatly reduced or absent in our reconstruction.

  20. [Failure of sublingual immunotherapy to treat latex allergy. A report of a case].

    Science.gov (United States)

    Morfin Maciel, Blanca María; Castillo Morfin, Blanca María

    2008-01-01

    Natural rubber latex has been in widespread use for over a century. Reports of immediate hypersensitivity to latex have increased dramatically since the first case was reported in 1979, specially in persons with cumulative latex exposure. A 13 year old male was referred to our office. He had been wearing orthodontic rubber bands for two years. The previous year he started having itchy, red and watery eyes, with sneezing and runny nose when he was exposed to rubber products. Then he developed oral edema and lip ulcers. Finally, he experienced cough, wheezing, chest tightness and dyspnea. The patient had no history of undergoing surgery, and his mother denied pacifier use. He had no history of fruit and vegetables allergy. Physical examination revealed conjunctival hyperemia, with fine papillary response in the upper tarsal plate, hyaline rhinorrhea, turbinate hypertrophy and perioral ulcers. Skin prick test were positive for latex and Quercus albus. Patch test with latex glove was negative, but positive with rubber tourniquet. Total IgE was 365 UI/mL. Latex-specific IgE testing confirmed the diagnosis. Spirometric values were normal. He started rush sublingual immunotherapy with latex extract. When he had finished, he traveled abroad. At immigration the inspectors examined him with latex gloves. Immediately he developed anaphylaxis, needing urgent medical attention. Although the efficacy and safety of sublingual immunotherapy for latex allergy has been demonstrated, the most effective strategy is complete avoidance of latex-containing products. World Public Health Services must promote the use of synthetic elastomer gloves in airports worldwide. PMID:19058485

  1. Chemical Properties of Juvenile Latex Timber Clone Rubber wood Trees

    International Nuclear Information System (INIS)

    Latex timber clone (LTC) rubber wood trees were introduced by Lembaga Getah Malaysia (LGM) for obtaining good yield of latex as well as the quality timber. Two juvenile clones namely RRIM2009 and RRIM2024 were selected for measuring the chemical properties based on TAPPI standards and were assessed at different height levels (top, middle and bottom). These chemical properties of wood can serve as an indicator for predicting the wood behavior for specific end usage. The findings revealed that there were significant variation between the clones and the highest value was obtained at the bottom portion except for lignin content. Clone RRIM2009 exhibited higher percentage of ash content (0.80 %) and lignin content (17.30 %). While Clone RRIM2024 has greater value of holocellulose content (58.58 %) and alpha-cellulose content (41.41 %). According to the different height levels, top portion exhibited highest lignin content (17.64 % for RRIM2009 and 16.75 % for RRIM2024). While bottom portion exhibited highest holocellulose (58.93 % for RRIM2009 and 60.56 % for RRIM2024), highest alpha-cellulose (39.75 % for RRIM2009 and 43.02 % for RRIM2024) and highest ash content (0.85 % for RRIM2009 and 0.71 % for RRIM2024). As a whole, clone RRIM2024 gave higher value except for lignin and ash content compared to RRIM2009. Thus, the potential of using such LTC rubber wood trees for specific purposes is promising. (author)

  2. Technology development of natural rubber latex products by radiation

    International Nuclear Information System (INIS)

    Development of radiation vulcanized natural rubber latex (RVNRL) was conducted to produce 2-3 tons of RVNRL per batch. The sensitizer used was 5 phr of 2 ethylhexyl acrylate and 1 phr of CCl4 which required vulcanization dose of 15 kGy. Irradiation vessel was thin stainless steel box of 15 cm width with capacity of 180 l. Two boxes could fill into one carrier of gamma irradiator at Thai irradiation Center (TIC). Once thorough irradiation could produce 3200 l of RVNRL per batch. Average dose rate, determined by nylon thin film at 21 points in the tank was 0.83 kGy/hr with over dose ratio of 1.4. The RVNRL was successfully made to exam gloves at a glove manufacturing factory by coagulant dipping. Optimum condition of the dipping were: TSC 50-52%, partial dry at 900C after dipping of dwell time 50 seconds, dried after beading at 700C and heated to full vulcanized at 1100C. The RVNRL was also successfully made to thick wall products such as baby nipple by heat sensitive dipping using 1.8% of polyvinyl methyl ether in the latex

  3. Natural rubber latex allergy after 12 years: recommendations and perspectives.

    Science.gov (United States)

    Charous, B Lauren; Blanco, Carlos; Tarlo, Susan; Hamilton, Robert G; Baur, Xaver; Beezhold, Donald; Sussman, Gordon; Yunginger, John W

    2002-01-01

    Natural rubber latex (NRL) allergy is a "new" illness whose prevalence reached epidemic proportions in highly exposed populations during the last decade. In children with spina bifida and in patients exposed to NRL during radiologic procedures, institution of prophylactic safety measures has had demonstrable effects in preventing allergic reactions. The risk of NRL allergy appears to be largely linked to occupational exposure, and NRL-associated occupational asthma is due almost solely to powdered latex glove use. Prevalence of NRL-allergic sensitization in the general population is quite low; several studies of young adults demonstrate rates of positive skin test results that are less than 1%. After occupational exposure, rates of sensitization and NRL-induced asthma rise dramatically in individuals using powdered NRL gloves but not in individuals using powder-free gloves. Airborne NRL is dependent on the use of powdered NRL gloves; conversion to non-NRL or nonpowdered NRL substitutes results in predictable rapid disappearance of detectable levels of aeroallergen. For these reasons, adoption of the following institutional policies designed to prevent new cases of NRL allergy and maximize safety is recommended: (1) NRL gloves should be used only as mandated by accepted Standard Precautions; (2) only nonpowdered, nonsterile NRL gloves should be used; and (3) nonpowdered, sterile NRL gloves are preferred for use. Low-protein powdered, sterile gloves may be used, but only in conjunction with an ongoing assessment for development of allergic reactions. PMID:11799362

  4. Cost evaluation of radiation vulcanization of natural rubber latex

    International Nuclear Information System (INIS)

    Cost of radiation vulcanized NR latex was evaluated. The plant would be built in an existing dipping factory in an industrial area in a Southeast Asian country. One thousands dry tons of NR latex are vulcanized with a low energy electron accelerator. The electron accelerator is a self-shielding low energy type. The maximum accelerating voltage is 300 kV and the output power is 10 kW. The total construction cost of the plant is $400,000 including electron accelerator and other equipments. Costs of raw materials and utilities are $1.165 and $0.023 per one kg of product, respectively. The fixed costs of the plant consist of labor costs, labor overhead, maintenance, plant overhead, depreciation, and bank interest. It is $0.190/kg of product. The company overhead for operation including company management, R and D and insurance is $0.044/kg of product. Thus, the total production cost is estimated to be $1.422/kg of product. (author)

  5. Cross-linked network development in compatibilized alkyd/acrylic hybrid latex films for the creation of hard coatings.

    Science.gov (United States)

    Wang, Tao; de las Heras Alarcón, Carolina; Goikoetxea, Monika; Beristain, Itxaso; Paulis, Maria; Barandiaran, Maria J; Asua, José M; Keddie, Joseph L

    2010-09-01

    Hybrids made from an alkyd resin and an acrylic copolymer can potentially combine the desired properties of each component. Alkyd/acrylic hybrid latex particles were synthesized via miniemulsion polymerization and used to create films at room temperature. Comparisons of the alkyd auto-oxidative cross-linking rates and the associated network development are made between two alkyd resins (with differing levels of hydrophilicity as measured by their acid numbers). The effects of increasing the compatibilization between the alkyd and the acrylic phase via functionalization with glycidyl methacrylate (GMA) are investigated. Magnetic resonance profiling and microindentation measurements reveal that film hardening occurs much faster in a GMA-functionalized alkyd hybrid than in the standard hybrid. The film's hardness increases by a factor of 4 over a 5-day period. The rate of cross-linking is significantly slower in nonfunctionalized alkyd hybrid films and when the more hydrophilic alkyd resin is used. Tensile deformation of the hybrid latex films reveals the effects of GMA functionalization and drier concentration in creating a denser cross-linked network. Modeling of the tensile deformation behavior of the hybrid films used a combination of the upper convected Maxwell model (to describe the viscoelastic component) and the Gent model (to describe the elastic component). The modeling provides a correlation between the cross-linked network formation and the resulting mechanical properties. PMID:20704338

  6. Development of Diagnostic Microscopic and Chemical Markers of Some Euphorbia Latexes

    Institute of Scientific and Technical Information of China (English)

    Uppuluri Venkata Mallavadhani; Kantamreddi Venkata Siva Satyanarayana; Anita Mahapatra; Akella Venkata Subrahmanya Sudhakar; Kilambi Narasimhan; Devendar Kumar Pandey; Manikkannan Thirunavokkarasu

    2006-01-01

    The latexes of the three Euphorbia species, namely E. antiquorum L., E. nerifolia L., and E. tirucalli L., are highly valued in the Indian system of medicine as purgatives, in addition to their specific and distinct therapeutic activities. In order to distinguish these latexes and develop their diagnostic microscopic and chemical markers, we performed extensive chemical and microscopic studies. The three latexes differ significantly in their microscopic features by exhibiting characteristic starch grain patterns. Although amoebic structures were found to be characteristic of E. antiquorum, dumb-bell and oval structures are characteristic of E. nerifolia and E. tirucalli, respectively. In addition, these latexes showed bone-shaped structures as a common feature, but these differed considerably in their length (10-60, 30-55, and 50-70 μm in length in E. antiquorum, E. nerifolia, and E. tirucalli, respectively). The chemical markers nerifoliene and euphol were found to be common to both E. antiquorum and E. nerifolia, whereas euphol is the only marker for E.tirucalli. A reverse-phase high-performance thin-layer chromatographic (HPTLC) method was developed to distinguish these three latexes and to generate their standard fingerprinting patterns. Most significantly,the markers nerifoliene and euphol could be resolved by RP-18 F254s precoated aluminium plates and the latexes have been quantitatively estimated with respect to these markers. The developed microscopic,chemical and HPTLC patterns can be used to distinguish the three latexes.

  7. Natural rubber latex: glove use, sensitization, and airborne and latent dust concentrations at a Denver hospital.

    Science.gov (United States)

    Page, E H; Esswein, E J; Petersen, M R; Lewis, D M; Bledsoe, T A

    2000-06-01

    Exposure to natural rubber latex may cause immediate hypersensitivity reactions. Published latex sensitization prevalence rates range from 2.9% to 22% among health care workers, and from 0.12% to about 20% of occupationally unexposed populations. In this study, self-administered questionnaires addressed job and personal characteristics, glove use, and symptoms in two groups of hospital workers: those who regularly used latex gloves and those who did not. Serum was tested for latex-specific immunoglobulin E. Air, surface, and air-filter dust samples for natural rubber latex were collected. The prevalence of latex sensitization was 6.3% in the non-users and 6.1% in the latex glove users (P = 0.9); 81.3% of sensitized workers were atopic compared with 59.5% of non-sensitized workers (P glove users (23.4%) than in the non-users (4.9%), as were rhino-conjunctivitis (16.3% and 7.9%, respectively, [P glove use was not a risk factor for sensitization. PMID:10874654

  8. Serological prevalence of anti-latex IgE antibodies in unselected blood donors in Argentina.

    Science.gov (United States)

    Docena, G H; Fossati, C A

    2005-01-01

    The prevalence of specific IgE to natural rubber latex proteins in the general population remains uncertain. The purpose of this study was to determine the prevalence of sera containing specific IgE antibodies to latex proteins using immunoenzymatic methods. A population of 500 unselected adult voluntary blood donors was the source of the sera used in this study. Two different immunoenzymatic methods (EAST and CARLA) were used to analyze the presence of specific IgE antibodies. Confirmation assay was carried out by inhibition ELISA and immunoblotting. Sera from healthy nonatopic individuals were also used as control. Two hundred and twenty five sera showed higher than normal total IgE levels. Of those, three presented latex specific IgE antibodies, which could be inhibited in a dose-response manner with the natural rubber latex and glove extracts. Several latex allergens were recognized by the IgE antibodies from these positive sera. This low seroprevalence (0.66%) indicates that latex hypersensitivity is not an important problem in the general population. We believe that prevention of latex exposure is only necessary in high risk groups of patients. PMID:15864882

  9. Technology Transfer Difficulties of Glove Making from Irradiated Latex into Home Industry

    International Nuclear Information System (INIS)

    A skill training of glove making is a tool for technology transfer. Research on the radiation vulcanization of natural rubber latex results variable characteristics of the rubber latex. Scientifically the superior characteristics of vulcanized irradiated latex has a good effect for healthiness and environment. Theoretically it supports the utilization of the latex. The science get from research reach to the community through an information from newspaper and symposium. The technology of making rubber glove from irradiated latex has been introduced and done as good as possible through a short training to the community in Inpres Desa Tertinggal (IDT) to develop either the science and technology of the irradiated latex or the application as well. It is not easy to develop the science and technology of the irradiated latex in order that it may be accepted and used in industry. It is hoped the training can stimulate a growing new rubber good industry. And the motivation of the training in glove making is a mission of Batan in developing the science and technology. (author)

  10. Photoluminescence, thermoluminescence and EPR studies of solvothermally derived Ni2+ doped Y(OH)3 and Y2O3 multi-particle-chain microrods

    International Nuclear Information System (INIS)

    Rod like structures of hexagonal Y(OH)3:Ni2+ and cubic Y2O3:Ni2+ phosphors have been successfully synthesized by solvothermal method. X-ray diffraction studies of as-formed product shows hexagonal phase, whereas the product heat treated at 700 °C shows pure cubic phase. Scanning electron micrographs (SEM) of Y(OH)3:Ni2+ show hexagonal rods while Y2O3:Ni2+ rods were found to consist of many nanoparticles stacked together forming multi-particle-chains. EPR studies suggest that the site symmetry around Ni2+ ions is predominantly octahedral. PL spectra show emission in blue, green and red regions due to the 3T1(3P)→3A2(3F), 1T2(1D)→3A2(3F) and 1T2(1D)→3T2(3F) transitions of Ni2+ ions, respectively. TL studies were carried out for Y(OH)3:Ni2+ and Y2O3:Ni2+ phosphor upon γ-dose for 1–6 kGy. A single well resolved glow peaks at 195 and 230 °C were recorded for Y(OH)3:Ni2+ and Y2O3:Ni2+, respectively. The glow peak intensity increases linearly up to 4 kGy and 5 kGy for Y(OH)3:Ni2+ and Y2O3:Ni2+, respectively. The kinetic parameters such as activation energy (E), frequency factor (s) and order of kinetics (b) were estimated by different methods. The phosphor follows simple glow peak structure, linear response with gamma dose, low fading and simple trap distribution, suggesting that it is quite suitable for radiation dosimetry. - Highlights: • We present a simple, solvothermal synthesis of Ni2+ doped Y(OH)3, Y2O3. • TL characteristics of γ-irradiated transition metal doped Y2O3 is reported. • Y2O3:Ni2+ exhibit enhanced luminescence emission than Y(OH)3:Ni2+. • γ-Irradiated Y(OH)3:Ni2+ and Y2O3:Ni2+ exhibit good thermoluminescence response

  11. Binding kinetics of magnetic nanoparticles on latex beads and yeast cells studied by magnetorelaxometry

    International Nuclear Information System (INIS)

    The ion exchange mediated binding of magnetic nanoparticles (MNP) to modified latex spheres and yeast cells was quantified using magnetorelaxometry. By fitting subsequently recorded relaxation curves, the kinetics of the binding reactions was extracted. The signal of MNP with weak ion exchanger groups bound to latex and yeast cells scales linearly with the concentration of latex beads or yeast cells whereas that of MNP with strong ion exchanger groups is proportional to the square root of concentration. The binding of the latter leads to a much stronger aggregation of yeast cells than the former MNP

  12. Study on irradiation condition in radiation vulcanization of natural rubber latex

    International Nuclear Information System (INIS)

    The effect of gamma rays irradiation dose rates on RVNRL preparation was studied using Malaysian latex added with O.2 phr of KOH and 5 phr n-BA. The results showed, to ensure the tensile strength of the latex film meet the requirement, when applying vulcanisation doses, Dv of 20 kGy 20 and 15 kGy, irradiation dose rates should not be greater than 0. 49 kGy/hr and 1. 6 kGy/hr respectively. Its was found that within the storage time of 20 days there was no change in the physical properties of the latex films

  13. Latex-modified grouts for in-situ stabilization of buried transuranic/mixed waste

    International Nuclear Information System (INIS)

    The Department of Applied Science at Brookhaven national Laboratory was requested to investigate latex-modified grouts for in-situ stabilization of buried TRU/mixed waste for INEL. The waste exists in shallow trenches that were backfilled with soil. The objective was to formulate latex-modified grouts for use with the jet grouting technique to enable in-situ stabilization of buried waste. The stabilized waste was either to be left in place or retrieved for further processing. Grouting prior to retrieval reduces the potential release of contaminants. Rheological properties of latex-modified grouts were investigated and compared with those of conventional neat cement grouts used for jet grouting

  14. Latex of "Coroa de Cristo" (Euphorbia Splendens: an effective molluscicide

    Directory of Open Access Journals (Sweden)

    Maurício C. de Vasconcelos

    1986-12-01

    Full Text Available An aqueous solution of the latex of "coroa de cristo" (Euphorbia splendens var. hislopii showed molluscicide action (LD90 at a concentration lower than 0.5 ppm on Biomphalaria glabrata and B. tenagophila reared in laboratory and at a concentration lower than 4.0 ppm for field B. tenagophila.Foi estudada em laboratório a atividade moluscicida do látex da "coroa de cristo" (Euphorbia splendens var. hislopii. A planta apresentou ação moluscicida (DL90 a uma concentração inferior de 0,5ppm para Biomphalaria glabrata e Biomphalaria tenagophila de laboratório e inferior a 4ppm para caramuhos de campo.

  15. Plant latex: A natural source of pharmaceuticals and pesticides

    Directory of Open Access Journals (Sweden)

    Ravi K Upadhyay

    2011-01-01

    Full Text Available In recent times use of plant natural products has increased tremendously, and there is a very high demand of herbal products for therapeutic, clinical, agricultural purposes. Plant latex is a rich source of pharmaceuticals, pesticides and immune allergens. It also contains important biomolecules such as glycosides, tannins, phytosterols, Flavonoids, acetogenins and saponins, which show diverse biolgical activities against bacteria, fungi, viruses, protozoans, nematodes, insects, and cancer and tumours. It is also used as disinfectant, anticoagulant, anti-inflammatory, antioxidant and antiproliferative agent that provides protection in wounds. It contains wide variety of industrially important metabolic substances which can be harvested, modified, quenched, and polymerized easily for making goods and materials by up-gradation of technology. No doubt it is a future raw material for many bioengineering and biotechnological industries.

  16. Bioactive triterpene derivatives from latex of two Euphorbia species.

    Science.gov (United States)

    Mazoir, Noureddine; Benharref, Ahmed; Bailén, María; Reina, Matías; González-Coloma, Azucena

    2008-04-01

    We have investigated the antifeedant and toxic effects of 23 semisynthetic terpenoid derivatives obtained through chemical modifications of the major components of Euphorbia resinifera (alpha-euphol and alpha-euphorbol) and E. officinarum (obtusifoliol and 31-norlanostenol) latex on several insect species (Spodoptera littoralis, Myzus persicae and Rhopalosiphum padi), their selective cytotoxicity on insect Sf9 and mammalian CHO cells and their phytotoxic effects on Lactuca sativa. The conversions focused mainly on positions 3,7,11, and 24 with several oxidizing agents. A total of 18 compounds affected S. littoralis growth (IGR). Our results support the importance of the C-3 substituent, suggest the involvement of the C-7 substituent and indicate that the C-3 hydroxyl is not essential for the IGR effect. Overall, Sf9 cells were more sensitive to the active compounds than CHO cells. All of these compounds had non selective moderate phytotoxic effects on radicle elongation of L. sativa. PMID:18304594

  17. Stabilization of radiation vulcanized natural rubber latex film

    International Nuclear Information System (INIS)

    Radiation vulcanized natural rubber latex (RVNRL) film has poor aging characteristics especially after it has been subject to leaching. The effect of the addition of antioxidants on the aging properties of RVNRL obtained using carbon tetrachloride and n-butyl acrylate (n-BA) as sensitizers respectively were evaluated. Antioxidant 2'2'-methylene-bis-(4-methyl-6-tert-butylphenol) containing 0.8 phr was found to be the most effective for RVNRL produced by using CCl4 as sensitizer and antioxidant 2,4-Bis[(octylthio)methyl]-o-cresol containing 1.0 phr for RVNRL produced by using n-BA as sensitizer. Antioxidant 2-mercaptobenzimidazole showed slightly less effective but gave less tendency for discolouration compared to 2.4-Bis[(octylthio)methyl]-o-cresol when used in the n-BA system. (author)

  18. A New Prenylated Xanthone from Latex of Garcinia cowa Roxb.

    Directory of Open Access Journals (Sweden)

    Zhi Na

    2013-05-01

    Full Text Available A new prenylated xanthone, 1,6-dihydroxy-3,7-dimethoxy-2-(3,7-dimethyloct-2,6-dienyl xanthone (3-O-methylcowaxanthone (1, together with four known xanthones, cowaxanthone (2, 7-O-methylgarcinone (3, α-mangostin (4 and γ-mangostin (5 were isolated from the latex of Garcinia cowa. The structure of compound 1 was elucidated on the basis of spectroscopic data interpretation, including 1D and 2D NMR and HREIMS. The cytotoxic activitiy of 1 against five human cancer cell lines, HL-60, SMMC-7721, A-549, MCF-7 and SW480, was evaluated, but it was inactive (IC 50>40μM.

  19. Purification of papain from fresh latex of Carica papaya

    Directory of Open Access Journals (Sweden)

    Rubens Monti

    2000-01-01

    Full Text Available In the present study we wish to report a method of crystallizing papain from fresh papaya latex which gave higher yields than previously reported. This method does not involve the use of sulphydryl reagents. The papain thus obtained is practically pure and shows a single band when submitted to electrophoresis on polyacrylamide gel, and is identical to the papain obtained by other methods. In routine enzymatic assays, specific activity was measured using Z-gly-pNP and BAEE as substrates. Papain crystallized by this method, without the use of high concentrations of salts or thiol-containing substances such as cysteine and dithiothreitol, is obtained in the form of a complex with natural inhibitors existent in latex which can be removed by dialysis.No presente trabalho apresenta-se um método de cristalização da papaína oriunda do látex fresco de mamão, o qual apresenta uma alta produtividade em relação aos métodos previamente descritos. A metodologia aqui descrita não envolve o uso de reagentes sulfidrílicos, a papaína foi obtida de forma praticamente pura, apresentando uma simples banda quando submetida a eletroforese, e com propriedades idênticas àquelas obtidas por outros métodos. A atividade específica foi determinada utilizando Z-gly-pNP e BAEE como substrato. A papaína obtida por essa metodologia, sem uso de substâncias tais como cisteína e ditiotreitol, apresenta-se na forma de um complexo com inibidores naturais, os quais podem ser removidos por diálise.

  20. Acrylic Rubber Latex in Ferrocement for Strengthening Reinforced Concrete Beams

    Directory of Open Access Journals (Sweden)

    D. R. Kumar

    2010-01-01

    Full Text Available Problem statement: In India, the early deterioration of reinforced concrete structures has become a big social problem in recent years. An essential research is needed for the development of effective repair materials and their execution systems comes to an important issue from the viewpoint of the longevity of infrastructures at present. Ferrocement laminates are introduced to enhance the overall performance of Reinforced Concrete (RC structures and these days the use of it is a promising technology for increasing the flexural strength of deficient reinforced concrete members. Approach: The repair system aims to provide quantitative repair enhancement as well as extending the life of deteriorated concrete members. This research in particular inspired the initiation of the present work which aimed to develop a material with unique properties and a very wide range of practical applications. The mechanical properties of mortar through difference in polymer content with Acrilic Latex by ferrocement among three different volume fractions of mesh reinforcement were studied. Following the encouraging progress made in the formulation and evaluation of the polymer modified repair mortar, tests were carried out involving the application of the reinforced repair material to the soffit of the reinforced concrete beams of 3 m length. Results: The levels of damage of the original beams prior to repair did not affect the ultimate load of the strengthened beams tested. The performance of the strengthened beams was compared to the control beams with respect to cracking, deflection and ultimate strength which confirm preeminent results. Conclusion: This accomplished the fact that acrylic rubber latex modified ferrocement is a doable alternative strengthening component for the rehabilitation of reinforced concrete structures. Further developments in these systems will create dramatic improvement into the field of rehabilitation of old privileged structures.

  1. El látex: Un importante aeroalergeno implicado en el asma ocupacional Latex: An important aeroallergen involved in occupational asthma

    Directory of Open Access Journals (Sweden)

    S. Quirce

    2003-01-01

    las manifestaciones de la enfermedad, tiene un mal pronóstico si no se aplican medidas encaminadas a reducir al máximo la exposición al látex.Latex has become one of the most frequent aetiological agents of occupational asthma in the last decade, especially amongst health personnel. The prevalence of occupational asthma due to latex in the different affected occupations varies between 2.5 and 10%, figures that give an idea of the magnitude of the problem. Latex proteins, absorbed in the dust of cornstarch, used as a lubricant, are responsible for asthma due to latex gloves. This cornstarch dust that covers the inside of the gloves acts as a vehicle for dispersing allergenic proteins. Latex aeroallergens are found in particles of different dimensions. The levels of latex aeroallergens in the environment capable of causing sensitization and of unleashing symptoms are not well defined. The determination of these levels of exposure to latex is complicated, since with latex one is dealing with a complex mixture of allergens with differing stability and bio-availability. The bioaerosol of latex is mainly produced by the active use of powdered gloves, but rugs or carpets and coverings act as important reservoirs of the allergen. Besides, the movement of people from areas with a high environmental concentration of latex constitutes an important means of dispersing the allergen, and probably ventilation systems as well. As in other cases of occupational asthma, diagnosis in many cases requires that a bronchial challenge be realized. The specific challenge tests through inhalation with latex have been carried out by different methods, which can be grouped by those that use an aqueous extract of latex and those that consist in handling or shaking gloves, which thus generate a dust aerosol. Each method has its advantages and drawbacks as described. Once the sensitized patient begins manifestations of the disease, his prognosis is poor if measures aimed at a maximum reduction

  2. Cofilin contributes to phagocytosis of IgG-opsonized particles but not non-opsonized particles in RAW264 macrophages.

    Science.gov (United States)

    Lu, Yanmeng; Cao, Lei; Egami, Youhei; Kawai, Katsuhisa; Araki, Nobukazu

    2016-06-01

    Cofilin is an actin-binding protein that severs actin filaments. It plays a key role in regulating actin cytoskeletal remodeling, thereby contributing to diverse cellular functions. However, the involvement of cofilin in phagocytosis remains to be elucidated. We examined the spatiotemporal localization of cofilin during phagocytosis of IgG-opsonized erythrocytes, IgG-opsonized latex beads and non-opsonized latex beads. Live-cell imaging showed that GFP-cofilin accumulates in the sites of IgG-opsonized particle binding and in phagocytic cups. Moreover, immunofluorescence microscopy revealed that endogenous cofilin localizes to phagocytic cups engulfing IgG-opsonized particles, but not non-opsonized latex beads. Scanning electron microscopy demonstrated a notable difference in morphology between phagocytic structures in IgG-dependent and IgG-independent phagocytosis. In phagocytosis of IgG-opsonized particles, sheet-like pseudopodia extended along the surface of IgG-opsonized particles to form phagocytic cups. In contrast, in opsonin-independent phagocytosis, long finger-like filopodia captured non-opsonized latex beads. Importantly, non-opsonized beads sank into the cells without extending phagocytic cups. Our analysis of cofilin mutant expression demonstrates that phagocytosis of IgG-opsonized particles is enhanced in cells expressing wild-type cofilin or active mutant cofilin-S3A, whereas the uptake of non-opsonized latex beads is not. These data suggest that cofilin promotes actin cytoskeletal remodeling to form phagocytic cups by accelerating actin turnover and thereby facilitating phagosome formation. In contrast, cofilin is not involved in opsonin-independent phagocytosis of latex beads. PMID:26754560

  3. Effect of coagulant on mechanical properties of radiation vulcanized NR latex film

    International Nuclear Information System (INIS)

    We have produced protective rubber gloves for radioactive contamination from vulcanized natural rubber latex with monomer (n-butyl acrylate). Properties of vulcanized NR film cast onto glass plates were lower than that of rubber gloves prepared by coagulant dipping. In order to find out the cause of this difference in physical properties, the effect of coagulant on these properties was investigated. Physical properties of cast film from radiation vulcanized NRL with 5 phr of 2-ethylhexyl acrylate/1 phr CCl4 increased remarkably by immersion in a 10 % Ca(NO3)2 solution. The crosslink density of the Ca(NO3)2-treated film was higher than that of the untreated film. From FTIR measurement, it was found that ammonium carboxylate (-COO--NH+4) in vulcanized NR converted to calcium carboxylate (-COO--CA2+--OOC-) by Ca(NO3)2 treatment. Furthermore, from the photographs of the cross section of the treated film by x-ray microanalyzer, calcium was detected. From these results, it is ascertained that the increase in physical properties by coagulant dipping is attributed to the inter particle crosslinking through Ca2+ ion. Thus, it clearly demonstrated that the Ca(NO3)2 leaching is favorable for the enhancement of physical properties of vulcanized NR. (author)

  4. Radiation vulcanization of natural rubber latex (NRL) using low energy electron beam accelerator

    International Nuclear Information System (INIS)

    The electron beam induced vulcanization of natural rubber latex has been studied using low energy Electron Beam (EB) accelerators of 300, 250 and 175 keV ne latex was irradiated in a special type stainless steel reaction reactor with a stirrer at the bottom of the reactor. From the results it was found that 300 and 250 keV accelerators could effectively vulcanize NRL. But accelerator of 175 keV is too low energy to vulcanize the latex. At the same time a drum type irradiator where thin layer of NRL was irradiated by accelerator, was used for vulcanization of NRL. This type of irradiator also showed good physical properties of vulcanized latex. The effects of beam current and stirrer speed on vulcanization were studied

  5. Proceedings of the international symposium on radiation vulcanization of natural rubber latex

    International Nuclear Information System (INIS)

    The First International Symposium on Radiation Vulcanization of Natural Rubber Latex (RVNRL) was held from 26 to 28 July 1989 at Tokyo and Takasaki. In these proceedings, thirty six papers presented at the Symposium are compiled. Main topics are commercial application of RVNRL, characterization of NR latex and vulcanization, properties of radiation vulcanized NR latex, development of sensitizers, mechanism of RVNRL, RVNRL with electron beams, and new Co-60 irradiator for RVNRL. Absence of nitrosamines and low cytotoxicity of radiation vulcanized NR latex are recognized as the remarkable advantages of RVNRL. The radiation vulcanization process for the production of protective rubber gloves for radioactive contamination was presented as the first commercial success in RVNRL. It was reported that various kinds of rubber articles for medical uses have being developed in West Germany. A sensitizer system consisting of n-butyl acrylate and t-butyl hydroperoxide was found to reduce the vulcanization dose to 8 kGy. (author)

  6. Maillard Reaction in Natural Rubber Latex: Characterization and Physical Properties of Solid Natural Rubber

    Directory of Open Access Journals (Sweden)

    S. Montha

    2016-01-01

    Full Text Available Maillard reaction in Natural Rubber (NR latex was investigated by treating fresh NR latex with glutaraldehyde (C5H8O2 in amounts of 0, 50, 100, and 200 mmol/kg of latex. Protein cross-linking in fresh NR latex and solid NR was confirmed by using sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE and attenuated total reflection infrared (ATR-IR spectroscopy, respectively. It was found that degree of protein cross-linking in NR increased with increasing C5H8O2 concentration. Physical properties of untreated and treated NR substances in terms of gel content, initial Wallace plasticity (P0, plasticity retention index (PRI, Mooney viscosity, and tensile strength were carefully explored. Results clearly showed that the Maillard cross-linking of proteins had remarkable effect on bulk NR properties, that is, solvent resistance, hardness, resistance to oxidation, rheological behavior, and resistance to stretching out.

  7. Processing researches on radiation vulcanization of natural rubber latex with low energy electron beam machine

    International Nuclear Information System (INIS)

    Processing researches on radiation vulcanization of natural rubber latex (RVNRL) was carried out with low energy electron beam machine, and explored the impact of RVNRL in a variety of factors. The results showed: It was beneficial to manufacture with increasing the dry rubber content of latex and increasing beam current. It was important to increase strength of RVNRL film using natural latex with higher green strength. Added to 0.5-1.5 phr (parts per hundreds of rubber) of PVA (polyvinyl alcohol) in radiation vulcanized latex, then the centrifugal method can greatly remove the water-soluble proteins, so that the residual water-soluble proteins in films or products can be reduced to acceptable levels. (authors)

  8. Latex glove sensitivity amongst diagnostic imaging healthcare personnel: a self-reporting investigation

    Energy Technology Data Exchange (ETDEWEB)

    Healy, Jan; Brennan, Patrick C. E-mail: patrick.brennan@ucd.ie; Bowden, Julie Anne

    2003-02-01

    The use of latex gloves has risen dramatically among healthcare workers resulting in an increase in the number of workers experiencing reactions to gloves. Little evidence of reactions among Irish healthcare workers is available. The current, self-reporting study investigated the prevalence to latex gloves amongst four professional groups within three Diagnostic Imaging Departments. Prevalence is similar to that demonstrated elsewhere with 18.3% of individuals expressing latex associated symptoms. Symptoms included itching and redness of hands, dry cracked skin, soreness of eyes and upper respiratory tract complaints. These results indicate that latex hypersensitivity is a real problem amongst Irish healthcare workers. This preliminary work provides the basis of a much larger controlled study currently being planned.

  9. Latex glove sensitivity amongst diagnostic imaging healthcare personnel: a self-reporting investigation

    International Nuclear Information System (INIS)

    The use of latex gloves has risen dramatically among healthcare workers resulting in an increase in the number of workers experiencing reactions to gloves. Little evidence of reactions among Irish healthcare workers is available. The current, self-reporting study investigated the prevalence to latex gloves amongst four professional groups within three Diagnostic Imaging Departments. Prevalence is similar to that demonstrated elsewhere with 18.3% of individuals expressing latex associated symptoms. Symptoms included itching and redness of hands, dry cracked skin, soreness of eyes and upper respiratory tract complaints. These results indicate that latex hypersensitivity is a real problem amongst Irish healthcare workers. This preliminary work provides the basis of a much larger controlled study currently being planned

  10. Preparation of Styrene-acrylate Latex Used in Ultra-low VOC Building Internal Wall Coating

    Institute of Scientific and Technical Information of China (English)

    CHEN Lijun; WU Fengqin; ZHUANG Xinyu; YANG Jian; LI Rongxian

    2008-01-01

    Styrene-acrylate latex with high glass transition temperature(Tg),low minimum film forming temperature(MFT)and good stability was prepared via core-shell emulsion polymerization.With semicontinuous process,high conversion rate of monomer and low gel rate were achieved.The weight ratio of core monomer to shell monomer was approximately 1.35.It is found that many factors such as emulsifiers,initiators,reaction temperature,pH value and polymerization technology have influences on the permormance of styrene-acrylate latex.The prepared latex was characterized by TEM and FTIR.The obtained latex with T of20.57℃,MFT of 5.0℃,and good stability,had good stability of film forming.

  11. Prevalence of Allergy to Natural Rubber Latex and Potential Cross Reacting Food in Operation Room Staff in Shiraz Hospitals -2006

    Directory of Open Access Journals (Sweden)

    H Nabavizade

    2007-07-01

    Full Text Available Introduction & Objective: Allergic reactions to natural rubber latex have increased during past 10 years especially among health care workers and patients with high exposure to latex allergens. Allergic reaction to latex is related to many diseases like occupational asthma. This study was performed to determine the prevalence of allergy to natural rubber latex and potential cross reacting food in operation room staff in Shiraz hospitals. Materials & Methods: In this cross-sectional descriptive study five hundred eighty operation room staff of ten private and state hospitals in Shiraz completed latex allergy questionnaire. They were questioned about personal history and previous history of latex sensitivity, symptoms of latex reactivity and about other allergies particularly to foods that may cross react with latex. Informed consent was obtained and skin prick testing was performed with natural rubber latex. Skin prick tests were done with three potentially cross reacting food (banana, Kiwi, and potato. The obtained data were analyzed with SPSS software and Chi-square test. Results: Among the 580 operation room workers 104 (17.9 % of participants were positive to latex skin test. We found a significant association between positive skin test to latex in operation room staff and atopy, urticaria and food allergy. Positive skin test to latex related to positive kiwi skin test (p<0.05. The prevalence did not vary by sex, age, education, surgical and non surgical glove users, history of contact dermatitis or smoking status. Conclusion: Latex allergy has a high prevalence in personnel of operation room. Evaluation of present symptom and prediction of future disease necessitate screening test in individuals at risk.

  12. Polylactide/Montmorillonite Hybrid Latex as a Barrier Coating for Paper Applications

    OpenAIRE

    Davide Bandera; Meyer, Veronika R.; David Prevost; Tanja Zimmermann; Boesel, Luciano F.

    2016-01-01

    We developed a paper coating for the potential application in food packaging based on polylactide and montmorillonite. It is applied to the paper in the form of a stable, water-based latex with a solid content of 25–28 wt %. The latex is prepared from a commercially available polylactide, surfactants, montmorillonite, a plasticizer, chloroform (to be removed later) and water by an emulsion/solvent evaporation procedure. This coating formulation is applied to the paper substrate by bar-coating...

  13. Performance Analysis of Styrene Butadiene Rubber-Latex on Cement Concrete Mixes.

    OpenAIRE

    Er. Kapil Soni; Dr. Y. P Joshi

    2014-01-01

    To improve the performance of concrete, polymers are mixed with concrete. It has been observed that polymer-modified concrete (PMC) is more durable than conventional concrete due to superior strength and high durability. In this research, effect of Styrene-Butadiene Rubber (SBR) latex on compressive strength and flexural strength of concrete has been studied and also the optimum polymer (SBR-Latex) content for concrete is calculated. This research was carried out to establish t...

  14. Synthesis of novel polymethacrylates with siloxyl bridging perfluoroalkyl side-chains for hydrophobic application on cotton fabrics

    Science.gov (United States)

    Cai, Lu; Dai, Li; Yuan, Yanhua; Liu, Anqi; Zhanxiong, Li

    2016-05-01

    Three novel fluorinated methacrylate monomers with siloxyl bridging perfluoroalkyl groups were synthesized and characterized. Afterwards, the corresponding polymethacrylate latexes, namely monofluoroalkylsiloxyl polymethacrylate (PMFSMA), bisfluoroalkylsiloxyl polymethacrylate (PBFSMA) and trisfluoroalkylsiloxyl polymethacrylate (PTFSMA), were prepared and coated onto cotton fabrics to make them water-repellent. Particle size, particle size distribution, zeta potential and high-resolution transmission electron microscope (TEM) were tested to assess the emulsion stability and particle morphology. Thermal properties of PTFSMA were evaluated by thermal-gravimetric analysis (TGA). Surface properties of the coated cotton fabrics were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), water contact angle (WCA), adhesive force and X-ray photoelectron spectroscopy (XPS). It was found that the incorporation of more perfluoroalkyl chains and the annealing process could decrease the surface free energy of polymer film to 13.7 mN/m. Furthermore, the EDS spectra of PTFSMA film after annealing showed an enrichment of fluorine in the film-air interface.

  15. Effects of Euphorbia milii latex on mitogen-induced lymphocyte proliferation

    Directory of Open Access Journals (Sweden)

    I.F. Delgado

    2014-03-01

    Full Text Available The crude latex of "Crown-of-Thorns" (Euphorbia milii var hislopii, syn E.splendens is a potent plant molluscicide. For this reason, toxicological studies have been performed to evaluate the health risks posed by its use in schistosomiasis control programs. The present study is part of a more comprehensive immunotoxicological evaluation of this molluscicide. Here, we investigated the effects of E. milii latex on the proliferation of human lymphocytes in vitro. Lyophilized latex of E. milii (0, 0.5, 5, 25 and 50 µg/ml was incubated with whole blood in the presence of proliferation stimulators, i.e. lectins (phytohemagglutinin, concanavalin A and pokeweed mitogen, as well as with human monoclonal antibody against CD3 and tetanus toxoid. Cell proliferation was measured by ³H-thymidine incorporation, and the effects of latex on mitogen-induced cell proliferation were compared to the effects of 10 ng/ml of 12-O-tetradecanoylphorbol-13-acetate (TPA. Results showed that mitogen-induced cell proliferation was markedly enhanced by E. milii latex. This synergistic effect of latex on mitogen-induced lymphocyte proliferation may be due to the presence of TPA-like phorbol esters and/or to mitogenic plant lectins.

  16. Biodegradability and aging study of rubber films obtained by gamma radiation vulcanization processes of latex

    International Nuclear Information System (INIS)

    The natural rubber latex (NRL) is industrially crosslinked by the conventional process of vulcanization, which uses sulphur and heat. Otherwise, the network can also be done by the alternative process with ionizing radiation. In this work the crosslinking of NRL was studied by the comparison of the conventional vulcanization system and the ionizing radiation process of 60C source. The products obtained, the irradiated latex, the irradiated latex with approximately 1% of soy lecithin and the sulphur vulcanized latex were tested by accelerated aging with ultraviolet (UV) and outdoor aging with compostage, tensile strength at break, swelling and gel fraction, fungi micro biota, scanning electron microscopy (SEM), infrared spectroscopy (FTIR) and thermogravimetry and differential scanning calorimetry analysis (TG and DSC). The results showed that the aging with microorganisms have a great influence in the physical properties of the samples. The thermal stability order observed showed that the sulphur vulcanized latex is more resistant, what is probably associated to a network more stable under the aging conditions. On the other hand, the irradiated latex showed intense biodegradation aspects, particularly with the presence of the soy lecithin. (author)

  17. Capacitance Regression Modelling Analysis on Latex from Selected Rubber Tree Clones

    Science.gov (United States)

    Rosli, A. D.; Hashim, H.; Khairuzzaman, N. A.; Mohd Sampian, A. F.; Baharudin, R.; Abdullah, N. E.; Sulaiman, M. S.; Kamaru'zzaman, M.

    2015-11-01

    This paper investigates the capacitance regression modelling performance of latex for various rubber tree clones, namely clone 2002, 2008, 2014 and 3001. Conventionally, the rubber tree clones identification are based on observation towards tree features such as shape of leaf, trunk, branching habit and pattern of seeds texture. The former method requires expert persons and very time-consuming. Currently, there is no sensing device based on electrical properties that can be employed to measure different clones from latex samples. Hence, with a hypothesis that the dielectric constant of each clone varies, this paper discusses the development of a capacitance sensor via Capacitance Comparison Bridge (known as capacitance sensor) to measure an output voltage of different latex samples. The proposed sensor is initially tested with 30ml of latex sample prior to gradually addition of dilution water. The output voltage and capacitance obtained from the test are recorded and analyzed using Simple Linear Regression (SLR) model. This work outcome infers that latex clone of 2002 has produced the highest and reliable linear regression line with determination coefficient of 91.24%. In addition, the study also found that the capacitive elements in latex samples deteriorate if it is diluted with higher volume of water.

  18. Oral dosing with papaya latex is an effective anthelmintic treatment for sheep infected with Haemonchus contortus

    Directory of Open Access Journals (Sweden)

    Donnan Alison A

    2011-03-01

    Full Text Available Abstract Background The cysteine proteinases in papaya latex have been shown to have potent anthelmintic properties in monogastric hosts such as rodents, pigs and humans, but this has not been demonstrated in ruminants. Methods In two experiments, sheep were infected concurrently with 5,000 infective larvae of Haemonchus contortus and 10,000 infective larvae of Trichostrongylus colubriformis and were then treated with the supernatant from a suspension of papaya latex from day 28 to day 32 post-infection. Faecal egg counts were monitored from a week before treatment until the end of the experiment and worm burdens were assessed on day 35 post-infection. Results We found that the soluble fraction of papaya latex had a potent in vivo effect on the abomasal nematode H. contortus, but not on the small intestinal nematode T. colubriformis. This effect was dose-dependent and at tolerated levels of gavage with papaya latex (117 μmol of active papaya latex supernatant for 4 days, the H. contortus worm burdens were reduced by 98%. Repeated treatment, daily for 4 days, was more effective than a single dose, but efficacy was not enhanced by concurrent treatment with the antacid cimetidine. Conclusions Our results provide support for the idea that cysteine proteinases derived from papaya latex may be developed into novel anthelmintics for the treatment of lumenal stages of gastro-intestinal nematode infections in sheep, particularly those parasitizing the abomasum.

  19. Latex Rubber Gloves as a Sampling Dosimeter Using a Novel Surrogate Sampling Device.

    Science.gov (United States)

    Sankaran, Gayatri; Lopez, Terry; Ries, Steve; Ross, John; Vega, Helen; Eastmond, David A; Krieger, Robert I

    2015-01-01

    Pesticide exposure during harvesting of crops occurs primarily to the workers' hands. When harvesters wear latex rubber gloves for personal safety and hygiene harvesting reasons, gloves accumulate pesticide residues. Hence, characterization of the gloves' properties may be useful for pesticide exposure assessments. Controlled field studies were conducted using latex rubber gloves to define the factors that influence the transfer of pesticides to the glove and that would affect their use as a residue monitoring device. A novel sampling device called the Brinkman Contact Transfer Unit (BCTU) was constructed to study the glove characteristics and residue transfer and accumulation under controlled conditions on turf. The effectiveness of latex rubber gloves as sampling dosimeters was evaluated by measuring the transferable pesticide residues as a function of time. The validation of latex rubber gloves as a residue sampling dosimeter was performed by comparing pesticide transfer and dissipation from the gloves, with the turf transferable residues sampled using the validated California (CA) Roller, a standard measure of residue transfer. The observed correlation (Pearson's correlation coefficient R(2)) between the two methods was .84 for malathion and .96 for fenpropathrin, indicating that the BCTU is a useful, reliable surrogate tool for studying available residue transfer to latex rubber gloves under experimental conditions. Perhaps more importantly, these data demonstrate that latex gloves worn by workers may be useful quantifiable matrices for measuring pesticide exposure. PMID:26302432

  20. The use of a pH-dependent and Non pH-dependent Natural Hydrophobic Biopolymer (Landolphia owariensis latex) as Capsule Coating Agents in in vitro Controlled Release of Metronidazole for Possible Colon Targeted Delivery

    OpenAIRE

    N C Obitte; A Chukwu; I V Onyishi

    2010-01-01

    Summary: Orally administered metronidazole often requires just a fraction of the administered dose for optimum local activity in the colon. Any formulation design that can target drug to the colon may require dose reduction while improving therapeutic activity. Colon targeted drug delivery achieves this fit. The objective of this work therefore was to evaluate the in vitro effect of, the percentage of surface area of capsule surface coated with Landolphia owariensis latex (LOL), particle size...

  1. Silica-Polystyrene Nanocomposite Particles Synthesized by Nitroxide-Mediated Polymerization and Their Encapsulation through Miniemulsion Polymerization

    Directory of Open Access Journals (Sweden)

    Elodie Bourgeat-Lami

    2007-01-01

    Full Text Available Polystyrene (PS chains with molecular weights comprised between 8000 and 64000 g⋅mol-1 and narrow polydispersities were grown from the surface of silica nanoparticles (Aerosil A200 fumed silica and Stöber silica, resp. through nitroxide-mediated polymerization (NMP. Alkoxyamine initiators based on N-tert-butyl-1-diethylphosphono-2,2-dimethylpropyl nitroxide (DEPN and carrying a terminal functional group have been synthesized in situ and grafted to the silica surface. The resulting grafted alkoxyamines have been employed to initiate the growth of polystyrene chains from the inorganic surface. The maximum grafting density of the surface-tethered PS chains was estimated and seemed to be limited by initiator confinement at the interface. Then, the PS-grafted Stöber silica nanoparticles were entrapped inside latex particles via miniemulsion polymerization. Transmission electron microscopy indicated the successful formation of silica-polystyrene core-shell particles.

  2. Reinforcement of natural rubber latex with silica modified by cerium oxide:preparation and properties

    Institute of Scientific and Technical Information of China (English)

    张福全; 廖禄生; 王永周; 汪月琼; 黄红海; 李普旺; 彭政; 曾日中

    2016-01-01

    Variable masses of nano cerium oxide (CeO2) were added into nano silica (SiO2) to prepare the well-dispersed SiO2-CeO2 suspension (SiO2-CeO2), cetyltrimethyl ammonium bromide (CTAB) was used to adjust the compatibility of SiO2-CeO2 with rubber matrix, then SiO2-CeO2 modified by CTAB and curing formulas were mixed with fresh natural rubber (NR) latex to prepare NR/SiO2-CeO2 nanocomposites that contained 0–10 parts of CeO2 by a new emulsion compounding method. The morphologies, cure characteristics, mechanical properties and thermal-oxidative stability of NR/SiO2-CeO2 nanocomposites were investigated. The re-sults revealed that the presence of CeO2 in NR/SiO2-CeO2nanocomposites was favorable for enhancing the interaction between NR matrix and fillers, helped to get smaller SiO2-CeO2 particles with narrower particle size distribution, further improved the crosslink densities and mechanical properties of NR/SiO2-CeO2 nanocomposites vulcanizates. Meanwhile, the addition of CeO2 increased the active energy at least 4.66%, obviously improved the thermal-oxidative aging-inhibiting properties of NR/SiO2-CeO2 nanocomposites. Additionally, nanocomposites containing CeO2 promotedTg shift to high temperature direction, causing the nanocomposites featured higher tanδ at 0 ºC and lower tanδ at 60 ºC and exhibited comparable wet grip and lower rolling resistance when NR/SiO2-CeO2nano-composites were used in tire tread compound.

  3. THE PREPARATION AND CHARACTERIZATION OF SBR/PS CORE-SHELL PARTICLES BY GAMMA IRRADIATION

    Institute of Scientific and Technical Information of China (English)

    Dai-shuang Li; Jing Peng; Xiao-hong Zhang; Jin-liang Qiao; Jiu-qiang Li; Gen-shuan Wei

    2005-01-01

    A kind of core(SBR)-shell(PS) particles was synthesized by using SBR latex and grafting with St under gamma irradiation. The influences of absorbed dose and dose rate on the grafting yield of PS on SBR seed latex have been investigated. Results show there was a transition layer which contained the SBR/PS graft copolymer between the SBR core and PS shell. Dynamic laser scattering (DLS) and differential scanning calorimetry (DSC) results confirm the existence of grafted polystyrene, and transmission electron microscope (TEM) observation verifies the core-shell structure of SBR-g-PS latex. Such SBR/PS core-shell latex could be processed easily to ultrafine rubber powders by using spray drying and expected to be used as an impact modifier for PS.

  4. Latex-allergic patients sensitized to the major allergen hevein and hevein-like domains of class I chitinases show no increased frequency of latex-associated plant food allergy

    OpenAIRE

    Radauer, Christian; Adhami, Farzaneh; Fürtler, Irene; Wagner, Stefan; Allwardt, Dorothee; Scala, Enrico; Ebner, Christof; Hafner, Christine; Hemmer, Wolfgang; Mari, Adriano; Breiteneder, Heimo

    2011-01-01

    Allergies to certain fruits such as banana, avocado, chestnut and kiwi are described in 30–70% of latex-allergic patients. This association is attributed to the cross-reactivity between the major latex allergen hevein and hevein-like domains (HLDs) from fruit class I chitinases. We aimed to assess the extent of cross-reactivity between hevein and HLDs using sera from latex-allergic patients with and without plant food allergy. Hevein and HLDs of latex, banana, and avocado chitinases were expr...

  5. Carbohydrate metabolism alterations in Biomphalaria glabrata infected with Schistosoma mansoni and exposed to Euphorbia splendens var. hislopii latex

    OpenAIRE

    Clélia Christina Mello-Silva; Mônica Magno Vilar; Maurício Carvalho Vasconcellos; Jairo Pinheiro; Maria de Lurdes de A Rodrigues

    2010-01-01

    This paper evaluates the alterations in the glycogen content of tissues (digestive gland and cephalopedal mass) and glucose in the haemolymph of Biomphalaria glabrata BH strain infected with Schistosoma mansoni BH strain and exposed to the latex of Euphorbia splendens var. hislopii. A reduction in the glycogen deposits was observed in infected snails exposed and not exposed to latex. However, the exposure to latex caused a greater depletion of the glycogen levels in both sites analysed, espec...

  6. Rapid determination of dry rubber content in natural rubber latex by low-resolution pulsed NMR technique

    International Nuclear Information System (INIS)

    The dry rubber content (DRC) of rubber latex varies considerably depending upon genetic and environmental conditions. To facilitate speedy evaluation of yield of experimental trees and quick payment to latex tappers on the basis of rubber content, there is need of a rapid and accurate method of determination of DRC in rubber latex. In the present paper a rapid, reliable and easy method for DRC determination using proton low resolution NMR is reported. 6 refs., 1 tab

  7. Carbohydrate metabolism alterations in Biomphalaria glabrata infected with Schistosoma mansoni and exposed to Euphorbia splendens var. hislopii latex

    Directory of Open Access Journals (Sweden)

    Clélia Christina Mello-Silva

    2010-07-01

    Full Text Available This paper evaluates the alterations in the glycogen content of tissues (digestive gland and cephalopedal mass and glucose in the haemolymph of Biomphalaria glabrata BH strain infected with Schistosoma mansoni BH strain and exposed to the latex of Euphorbia splendens var. hislopii. A reduction in the glycogen deposits was observed in infected snails exposed and not exposed to latex. However, the exposure to latex caused a greater depletion of the glycogen levels in both sites analysed, especially from the third week onward. The utilisation of latex as a molluscicide to control the population of infected B. glabrata selectively is proposed.

  8. On the release of metronidazole from natural rubber latex membranes

    International Nuclear Information System (INIS)

    The controlled release of drugs can be efficient if a suitable encapsulation procedure is developed, which requires biocompatible materials to hold and release the drug. In this study, a natural rubber latex (NRL) membrane is used to deliver metronidazole (MET), a powerful antiprotozoal agent. MET was found to be adsorbed on the NRL membrane, with little or no incorporation into the membrane bulk, according to energy dispersive X-ray spectroscopy. X-ray diffraction and FTIR spectroscopy data indicated that MET retained its structural and spectroscopic properties upon encapsulation in the NRL membrane, with no molecular-level interaction that could alter the antibacterial activity of MET. More importantly, the release time of MET in a NRL membrane in vitro was increased from the typical 6-8 h for oral tablets or injections to ca. 100 h. The kinetics of the drug release could be fitted with a double exponential function, with two characteristic times of 3.6 and 29.9 h. This is a demonstration that the induced angiogenesis known to be provided by NRL membranes can be combined with a controlled release of drugs, whose kinetics can be tailored by modifying experimental conditions of membrane fabrication for specific applications.

  9. Cluster analysis of WIBS single-particle bioaerosol data

    OpenAIRE

    N. H. Robinson; Allan, J. D.; Huffman, J. A.; P. H. Kaye; V. E. Foot; Gallagher, M

    2013-01-01

    Hierarchical agglomerative cluster analysis was performed on single-particle multi-spatial data sets comprising optical diameter, asymmetry and three different fluorescence measurements, gathered using two dual Wideband Integrated Bioaerosol Sensors (WIBSs). The technique is demonstrated on measurements of various fluorescent and non-fluorescent polystyrene latex spheres (PSL) before being applied to two separate contemporaneous ambient WIBS data sets recorded in...

  10. Two-phase synthesis of olive-like NiS particles and chain-like Bi2S3 nanowires

    Directory of Open Access Journals (Sweden)

    Yuan Yawen

    2015-03-01

    Full Text Available Highly dispersed olive-like NiS particles were synthesized in a liquid-liquid biphasic system at room temperature, where nickel xanthate in organic solvents (toluene and benzene and sodium sulfide in water solution were used as nickel and sulfide sources, respectively. NiS particles were formed at the stabilized phase interface. The structures, chemical composition and optical characteristics of the products were investigated by transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy and ultraviolet-visible spectroscopy. The organic solvents obviously influenced the morphology of the NiS particles. The olive-like NiS with smooth surface and sharp ends was obtained at benzene/water interface, while spindle-like NiS particles with rough surface and circle ends were formed when using toluene as a solvent. Analogously, chainlike Bi2S3 nanowires were produced at chloroform/water interface. The effect of the experiment parameters including reaction time, solvent and concentration of reactants on the size and morphology of the products was discussed in detail and a possible formation mechanism was suggested.

  11. [Coupling effects of water and chemical fertilizers on Hevea brasiliensis latex yield].

    Science.gov (United States)

    Hua, Yuan-Gang; Chen, Qiu-Bo; Lin, Zhao-Mu; Luo, Wei

    2008-06-01

    Water and nutrient are the two main factors limiting Hevea brasiliensis growth and its latex yield. With 17 year-old Clone SCATC 7-33-97 H. brasiliensis as test material, the coupling effects of water and chemical N, P and K fertilizers on latex yield were studied by general orthogonal rotation design of quadratic regression with four factors and five levels under field condition, and a regressive mathematical model was set up based on the latex yield by quadratic regression analysis. The results showed that all test coupling levels of water and chemical fertilizers had significant effects on the latex yield. The yield-increasing effect of test factors was in the order of N application rate > irrigation amount > P application rate > K application rate, while the coupling effect of water and chemical fertilizers was in the sequence of water and N > N and P > water and P > water and K. There was a negative coupling effect of K application rate and soil moisture content. For latex yield, the optimum application rates of chemical fertilizers were 476.39 kg x hm(-2) of urea, 187.70 kg x hm(-2) of superphosphate and 225.77 kg x hm(-2) of potassium chloride, and the optimum irrigation amount was to have 82.78% soil relative water content. PMID:18808010

  12. The influence of environmental factors on the molluscicidal activity of Euphorbia milii latex.

    Science.gov (United States)

    Oliveira-Filho, E C; De-Carvalho, R R; Paumgartten, F J

    1999-03-01

    The present study was undertaken to investigate the influence of biotic (snail size and presence of food during the test) and abiotic factors (temperature, water hardness and concentration of organic materials) on the molluscicidal activity of Euphorbia milii latex. Bioassays were conducted with B. glabrata (10 snails per concentration) and snail lethality was evaluated after 24 hr and 48 hr of exposure to lyophilized latex solutions. Neither the degree of water hardness, nor the presence of food during the test affected latex-induced snail mortality. The snail size had a minor influence on E. milii-induced snail lethality. Newly-hatched (shell diameter < or = 1 mm) as well as young (3-8 mm) snails were slightly less susceptible than older (10-25 mm) mollusks. On the other hand, the molluscicidal effect of E. milii latex was modified by environmental factors such as temperature (i.e., LC50 and LC90 values were halved for every 10 degrees C rise in temperature) and concentration of organic materials in the water (i.e. the higher the concentration of organic matter, the higher the LC50 value). The efficacy of E. milii latex as a molluscicide can be modified by factors such as water temperature and concentration of organic materials, and to a lesser extent by snail size. PMID:10507917

  13. Preparation and characterization of latex films photo-immobilized with IFN-α.

    Science.gov (United States)

    Wu, Lifang; Hu, Kaikai; Zhang, Li; Chen, Wuya; Chen, Xiaohui; You, Rong; Yin, Liang; Guan, Yan-Qing

    2016-09-01

    We developed a biomaterial by photo-immobilizing interferon-α (IFN-α) on the surface of latex condom films for the prevention and treatment of cervicitis, cervical cancers and diseases caused by cervical virus. The IFN-α modification by photoactive N-(4-azidobenzoyloxy) succinimide was characterized on a nano-scale by spectroscopy analysis and micro morphology. The anti-bacterial, anti-cancer, and anti-viral effects of the modified bioactive latex films were evaluated by antibacterial susceptibility testing, Gram staining, flow cytometry, immunofluorescence, and Western blotting. Our results showed that the photo-immobilized IFN-α latex films effectively inhibited the growth of both Neisseria gonorrhoeae and human cervical cancer HeLa cells. Moreover, the expression of anti-viral proteins, including P56, MxA, and 2', 5'-OAS, in the human cervical epithelial cell line NC104 was significantly increased by photo-immobilized IFN-α latex films. Taken together, these results suggest that photo-immobilized IFN-α latex films may have therapeutic effects against cervicitis, cervical cancers, and cervical virus. PMID:27137809

  14. Anti-Angiogenic Activity of Ficus carica Latex Extract on Human Umbilical Vein Endothelial Cells

    Directory of Open Access Journals (Sweden)

    Ali Mostafaie

    2011-01-01

    Full Text Available Angiogenesis, the formation of new blood vessels, is a key process in cancer developmentand metastasis. In this study, the anti-angiogenic and anti-proliferative potentials of Ficuscarica latex extract have been investigated using human umbilical vein endothelial cells(HUVECs.Different doses of latex extract were prepared and added to a three-dimensional culture ofHUVEC in a collagen matrix. After 3-5 days of treatment, the anti-angiogenic effects of theextracts were monitored microscopically. For the anti-proliferation assay, different dosesof the extracts were examined on HUVECs.The results clearly indicated that latex extract could inhibit proliferation and capillary tubeformation of HUVECs in a dose-dependent manner at the range of 100-400 μg/ml. In addition,the extract was not cytotoxic up to 450 μg/ml as assessed by trypan blue and lactatedehydrogenase (LDH cytotoxicity assays.It is concluded that latex extracts of F. carica contain strong anti-angiogenic andanti-proliferative activities. Our data indicates that latex extract could be a candidateas a potential agent for the prevention of angiogenesis in cancer and other chronicdisorders.

  15. Rubber/clay nanocomposites by combined latex compounding and melt mixing: A masterbatch process

    International Nuclear Information System (INIS)

    Highlights: → Rubber/Ca-montmorillonite nanocomposites were prepared by the masterbatch process. → Latex compounding method is efficient to improve the Ca-montmorillonite dispersion. → Exfoliated structure was obtained in the masterbatch by latex compounding method. → Intercalated and exfoliated structures were achieved in the vulcanizate. → The properties of vulcanizate are improved by the addition of Ca-montmorillonite. -- Abstract: Rubber/Ca-montmorillonite (Ca-MMT) nanocomposites with well exfoliated Ca-MMT layers were prepared by combination of latex compounding and melt mixing. Firstly, a high Ca-MMT content masterbatch was co-coagulated by natural rubber (NR) latex and modified Ca-MMT aqueous suspension through latex compounding. The masterbatch was added in the system of styrene butadiene rubber (SBR) and epoxidized natural rubber (ENR) by melt mixing subsequently. The X-ray diffraction (XRD) and transmission electronic microscopy (TEM) results showed that intercalated and exfoliated nanocomposites were obtained by the masterbatch technique. The effects of modified Ca-MMT introduction into the rubber matrix, via the masterbatch technique, on the properties of the resulting composites were studied. It was found that the vulcanization was hindered by the incorporation of modified Ca-MMT, while mechanical performances, thermal stability and aging resistance were improved. The increasingly glass transition temperature and the storage modulus with the loading of modified Ca-MMT were measured by dynamic mechanical analysis (DMA).

  16. Status RVNRL in German latex industry and its introduction to the European market

    International Nuclear Information System (INIS)

    Reasons to look for an alternative crosslinking system avoiding sulphur curing was the restrictive policy of the German Health Authorities concerning nitrosamines. It was concluded that radiation curing offers further advantages . By avoiding the accelerators, type IV allergy is excluded, cytotoxicity is minimised to a very low level, films have better clarity and when thoroughly leached higher electrical resistance. Treatment of waste give no SO sub 2 emissions by burning, no Zinc in the ashes and possibly better microbial degradation. A development was carried out to irradiate natural latex by electron beam with a Dynamitron equipment. It was found trimethylolpropanetrimethacrylate to be a suitable sensitizer. Because of to high prices this development was interrupted. For future application trials and efforts to introduce RVNRL in the market gamma ray radiated natural latex either from Batan, Indonesia or MINT, Malaysia are used. Mainly dipped goods were produce, but radiated natural latex has shown good results in other processes. During discussions with customers it has proved necessary to establish specifications for RVNRL. A serious problem using natural latex for the production of medical devices is the type I allergy. Attempts are made to dip surgical gloves, leach them thoroughly and control extractable proteins were reduced to the very low level of 6.5 μg/g. Out of 18 patients sensitive to natural latex protein wearing gloves made from RVNRL only six have shown a positive response. That means RVNRL could help to solve the protein allergy problem. Further developments on this line are scheduled

  17. Antibacterial and cytotoxic potential of silver nanoparticles synthesized using latex of Calotropis gigantea L.

    Science.gov (United States)

    Rajkuberan, Chandrasekaran; Sudha, Kannaiah; Sathishkumar, Gnanasekar; Sivaramakrishnan, Sivaperumal

    2015-02-01

    The present study aimed to synthesis silver nanoparticles (AgNPs) in a greener route using aqueous latex extract of Calotropis gigantea L. toward biomedical applications. Initially, synthesis of AgNPs was confirmed through UV-Vis spectroscopy which shows the surface plasmonic resonance peak (SPR) at 420 nm. Fourier transform infrared spectroscopy (FTIR) analysis provides clear evidence that protein fractions present in the latex extract act as reducing and stabilizing bio agents. Energy dispersive X-ray (EDAX) spectroscopy confirms the presence of silver as a major constituent element. X-ray diffractograms displays that the synthesized AgNPs were biphasic crystalline nature. Electron microscopic studies such as Field emission scanning electron microscopic (Fe-SEM) and Transmission electron microscope (TEM) reveals that synthesized AgNPs are spherical in shape with the size range between 5 and 30 nm. Further, crude latex aqueous extract and synthesized AgNPs were evaluated against different bacterial pathogens such as Bacillus cereus, Enterococci sp, Shigella sp, Pseudomonas aeruginosa, Klebsiella pneumonia, Staphylococcus aureus and Escherichia coli. Compared to the crude latex aqueous extract, biosynthesized AgNPs exhibits a remarkable antimicrobial activity. Likewise invitro anticancer study manifests the cytotoxicity value of synthesized AgNPs against tested HeLa cells. The output of this study clearly suggesting that biosynthesized AgNPs using latex of C. gigantea can be used as promising nanomaterial for therapeutic application in context with nanodrug formulation.

  18. Natural rubber latex: past, present and future in Latin America

    International Nuclear Information System (INIS)

    The origin of the Hevea braziliensis tree was the Amazonian region in South America, particularly the Brazilian jungle. The rubber expansion at the end of 9th century brought prosperity and determined the borders of Amazonian countries. In spite of that, the Brazilian government has failed in establishing a successful policy for improving the NR production in the jungle. However, rubber plantations were successfully introduced recently near marginal areas of the humid forest in the Amazon due to the absence of the fungus Microcyclos ulei. Both, extraction of wild rubber and plantation have a key role in the maintenance of the forest health. The market for dipping products is small but is growing very fast and is expected to follow this pattern as the sanitary conditions are improved by the health authority. The history of the Brazilian NR products industry is contemporary and is based on the policy of market protection and on the lack of investments due to extremely high interest rates. As a result, the industry was not competitive. It was concluded that, in order to cope with the future challenge, the industry is required to invest in very modern technologies to produce first class goods with international acceptance. Latin America would follow the world trend for nitrosamine and protein free products. The radiation vulcanization of natural rubber latex could prove itself as a profitable solution and not only a quality solution. It was also concluded that both wild rubber and rubber plantations in Brazil have their future coupled with the future of a regional dipping industry. Moreover, the buildup of the dipping industry will be beneficial to the protection of the humid forest and the recovery of degraded areas

  19. Silver nanoparticles delivery system based on natural rubber latex membranes

    International Nuclear Information System (INIS)

    The search for new materials for biomedical applications is extremely important. Here, we present results on the performance of a silver nanoparticles delivery system using natural rubber latex (NRL) as the polymeric matrix. Our aim was to obtain an optimized wound dressing by combining materials with potential healing action. The synthesis of silver nanoparticles and their characterization by UV–Vis spectroscopy, transmission electron microscopy, zeta potential, dynamic light scattering, and Fourier transform infrared spectroscopy (FTIR) are depicted. The NRL membranes are good matrix for silver nanoparticles and allow for their gradual release. The release of 30 nm silver nanoparticles by the NRL membranes depends on their mass percentage in NRL membranes. The total concentration of AgNP released by the NRL membranes was calculated. The AgNP attached to the cis-isoprene molecules in the NRL matrix remain attached to the membrane (∼0.1 % w/w). So, only the AgNP bound to the non-rubber molecules are released. FTIR spectra suggest that non-rubber molecules, like aminoacids and proteins, associated with the serum fraction of the NRL may be attached to the surfaces of the released nanoparticles, thereby increasing the release of such molecules. The released silver nanoparticles are sterically stabilized, more stable and well dispersed. Because the serum fraction of the NRL is responsible for the angiogenic properties of the matrix, the silver nanoparticles could increment the angiogenic properties of NRL. This biomaterial has desirable properties for the fabrication of a wound dressing with potential healing action, since it combines the angiogenic and antibacterial properties of the silver nanoparticles with the increased angiogenic properties of the NRL.Graphical AbstractThe AgNP attached to the cis-isoprene molecules remain in the NRL matrix and only the AgNP bound to the non-rubber molecules (NRL serum fraction) are released. The released AgNP are sterically

  20. In situ generated silica in natural rubber latex via the sol–gel technique and properties of the silica rubber composites

    International Nuclear Information System (INIS)

    Natural rubber (NR) composites reinforced by silica generated in situ within the NR matrix were prepared by the sol–gel process using tetraethoxysilane (TEOS) as the silica precursor. The effect of the TEOS content, water: TEOS mole ratio, reaction time and temperature on the in situ silica content formed in the NR latex were investigated. The results indicated that the suitable condition to produce a high silica content (54 parts by weight per hundred parts of rubber (phr)) in the rubbery matrix was the use of 200 phr TEOS and a water: TEOS mole ratio of 28.9:1 at room temperature for 24 h. The curing, mechanical, and thermal properties of the composite materials were also investigated. Increasing the in situ silica content increased the cure time and improved the mechanical properties of the composite. Compared to the NR vulcanizates filled with the commercial (ex situ formed) silica, the mechanical and thermal properties of the in situ silica composite material were significantly improved. Transmission electron microscopy revealed that the in situ formed silica particles were well distributed within the NR matrix, in contrast to the clumping of the ex situ formed commercial silica within the NR matrix. - Highlights: • High in situ silica content in NR latex was obtained up to 54 phr. • A good dispersion of in situ silica filling into the rubbery matrix. • Comparison of silica generated in the rubber matrix using solid, solution and latex NR substrates. • A good reinforcement effect of in situ silica was observed on the NR vulcanizate. • Sol–gel method is an alternative way to develop a novel composite material

  1. 丝胶接枝物改性天然乳胶的研究%Research of using silk sericin to modify natural rubber latex

    Institute of Scientific and Technical Information of China (English)

    孙金煜; 田晓慧; 元以中; 龚淑婷; 冯佼姣; 刘虎邱

    2011-01-01

    利用丝胶优良的抗氧化性和亲肤性等特点,将丝胶包覆在天然乳胶粒表面,从而隔绝了天然乳胶膜与皮肤的直接接触,改善天然乳胶制品对皮肤的过敏性反应,使其不仅具有耐氧化性,而且与皮肤接触后可有效防止肌肤干燥,抑制肌肤黑色素生成等.同时将水性聚氨酯通过先接枝后杂凝聚的方法,在不改变乳胶断裂伸长率的情况下,提高拉伸强度,实现了对天然乳胶过敏性和机械性能的双重改善.%By the use of excellent oxidation resistance and skin friendly of silk sericin, silk sericin coats the surface of natural rubber latex particles which could cut off the direct contact with the skin and improve allergy. It makes natural latex rubber could not only resist oxidation but also effectively avoid skin drying and prevent melanin' s generating. After heterocoagulating with aqueous polyure-thane grafting with silk sericin, natural rubber latex membrane could improve fracture strength without reducing its breaking elongation,realize the improvement of its anaphylaxis and mechanical properties.

  2. Corrected Version Specificity of the Latex Test for Cryptococcal Antigen: a Rapid, Simple Method for Eliminating Interference Factors†

    OpenAIRE

    Stockman, Leslie; Roberts, Glenn D.

    1983-01-01

    An enzymatic method involving a protease (pronase) for the elimination of interference factors in the latex test for cryptococcal antigen was developed and compared with dithiothreitol treatment. The two were equivalent in their ability to remove interference factors; however, the enzymatic method generally yielded higher titers. The method is simple, requires only 20 min, and makes the latex test for cryptococcal antigen specific.

  3. Production Of Hollow Toy Product From Radiation Pre vulcanized Natural Rubber Latex (RVNRL) By Using Casting And Moulding Technique

    International Nuclear Information System (INIS)

    Hollow toy products are very synonym to the child from the age of months since it able to stimulating each of their sense such as sight, hearing, taste, touch and smell. Most of hollow toy products are made from natural rubber latex by using moulding and casting technique. The moulding and casting technique is a manufacturing process by pored liquid latex into a mould, which contain cavity of the desired shape. The mould made from plaster of Paris able to absorbs water from latex meanwhile the presence of calcium ions from plaster of Paris will tend to diffuse into latex thus promote formation of deposit on surface of cavity mould. To improve the quality and safety of hollow toy product made from latex, Radiation Pre vulcanized Natural Rubber Latex (RVNRL) has been identified to be used because it can fulfill the standard requirement for latex and also due to its special abilities such as lower modulus (soft latex products), nitrosamines free, low in nitrosatables, free from chemical accelerators induced allergies and better biodegradability. This paper identify the problem appears from the process of making hollow toy products from RVNRL by using moulding and casting technique. (author)

  4. Effect of urea addition on the radiation vulcanisation of natural rubber latex

    International Nuclear Information System (INIS)

    Acrylate monomers have been in recent years to reduce the radiation dose required to vulcanise natural rubber latex, originally 300 kGy to 15 kGy. However, there is still a need to further reduce the dose requirement without increasing the sensitiser concentration. In the present study, the synergistic effect of addition of urea along with the sensitiser n-butyl acrylate (n-BA) on the crosslinking density and mechanical properties of radiation vulcanised natural rubber (RVNRL) film has been investigated. The results show that by addition of 0.2 part hundred rubber (phr) urea to the latex before irradiation, the crosslinking density and tensile strength increases by about 15% and 47% respectively. This increase has been attributed to the higher concentration of the sensitiser n-butyl acrylate in the rubber phase in presence of urea. The effects of urea addition on the ageing properties of the latex are being investigated. (author). 6 refs., 3 figs., 1 tab

  5. Extractable proteins from electron beam (EB) irradiated natural rubber (NR) latex

    International Nuclear Information System (INIS)

    The protein assay of natural rubber latex (NRL) vulcanized by low energy electron beam (EB, 300 keV, 30 mA) has been carried out using Bicinchoninic acid (BCA) reagent. Extractable protein in irradiated latex film was determined by measuring the absorption of colored solution at 562 nm using UV spectrometer. The effect of various radiation doses on the extractable protein content of NRL was investigated. It was ,found that the quantities of extractable protein increases with radiation dose. When compared with ,gamma-ray irradiated samples the same trend was observed. Electron beam irradiated latex films are leached in 1% (ammonia water for various lengths of time. From the results it was established that within 2 hours of leaching in ammonia water most of the extractable protein (96%) were removed from rubber film

  6. Primary prevention of latex allergy in healthcare-spectrum of strategies including the European glove standardization.

    Science.gov (United States)

    Wrangsjö, Karin; Boman, Anders; Lidén, Carola; Meding, Birgitta

    2012-04-01

    IgE-mediated allergy to natural rubber latex was first noted from rubber gloves in 1979. The initial reports in dermatological journals described contact urticarial reactions; later, severe generalized allergic reactions and asthma were documented. A considerable proportion of the people involved in medical and dental care were found to be sensitized to latex. This article describes and surveys a broad range of primary prevention measures at the local and national levels. Examples are given from paediatrics, dental education, and medical care. National strategies and position papers on latex allergy are presented in which medical professionals, manufacturers and public authorities have cooperated. Special reference is paid to the European work to standardize medical gloves, which led to document EN 455:3. PMID:22404191

  7. Molecular and biochemical evaluation of genetic effect of calotropics (Ait.) latex on aspergillus terreus thom

    International Nuclear Information System (INIS)

    On treating dense conidial suspensions of Aspergillus terreus Thom with different concentrations of Calotropis procera latex, for investigating the genotoxicity of the latter, it was found that latex of Calotropis procera had potent lethal and mutagenic activities. Survival percentage decreased as concentration or time of exposure increased. Frequency of auxotrophic mutants increased with increase in concentration or exposure time. Most auxotrophic mutants were amino acid requiring mutants. DNA and total protein contents of each mutant was significantly lower than wild type of Aspergillus terreus. RAPD demonstrated polymorphic genetic bands of electrophoretic products of PCR for all mutants compared with the wild type strain. SDS-PAGE results expressed a polymorphism of protein bands as well. All these results indicated the mutagenicity of the latex of Calotropis procera. (author)

  8. Extraction and comparison of proteins from natural rubber latex by conventional and ionizing radiation methods

    International Nuclear Information System (INIS)

    Several proteins in natural rubber latex (NRL) have been assigned to be significant allergens. It is known that proteins submitted to ionizing radiation suffer denaturation and immunochemical modification resulting in low antigenic reactivity. The aim of this study was to extract and compare water extractable proteins from NRL films vulcanized by conventional and by ionizing radiation methods. SDS-polyacrylamide gel electrophoresis (SDS--PAGE) and high pressure liquid chromatography (HPLC) showed a diffuse protein band of about 14 KDa, which we believe is rubber elongation factor (REF), in both eluates, but smaller in latex film vulcanized by ionizing radiation. REF has been suggested to be a major latex allergen. These data suggest that ionizing radiation vulcanization could be an useful method for the production of NRL goods with low antigenicity. (author). 8 refs., 2 figs., 1 tab

  9. Absence of tumor promoting activity of Euphorbia milii latex on the mouse back skin.

    Science.gov (United States)

    Delgado, I F; De-Carvalho, R R; De-Oliveira, A C A X; Kuriyama, S N; Oliveira-Filho, E C; Souza, C A M; Paumgartten, F J R

    2003-11-30

    Euphorbia milii (Euphorbiaceae) is a decorative plant used in gardens and living fences. In China, it has also been employed in herbal remedies for hepatitis and abdominal edema. Since E. milii latex--lyophilized or in natura--proved to be a potent plant molluscicide, its toxicity to non-target organisms has been comprehensively studied. Concerns on a possible tumor promoting activity have discouraged its use as a locally-available alternative molluscicide in schistosomiasis control programs. Two in vitro assays (inhibition of metabolic cooperation in V79 cells and Epstein-Barr virus induction in Raji cells) had suggested that E. milii latex contained tumor-promoting substances. This study was undertaken to verify whether the latex acts as a tumor promoter in vivo as well. A single dose of the initiating agent DMBA (400 nmol) was applied on the back skin of male and female DBA/2 mice. Testing for tumor promoting activity began 10 days after initiation. Tetradecanoyl phorbol acetate (TPA) (5 nmol, positive control), lyophilized latex (20, 60 and 200 microg per mouse) or acetone (vehicle control) were applied on mouse back skin twice a week for 20 weeks. In TPA-treated mice, papillomas were firstly noted during the 11th week, and by the 17th week all animals exhibited skin tumors. No tumors developed in mice treated with the solvent alone and in those exposed to latex. Findings from the present study therefore indicated that E. milii crude latex does not act as a tumor promoting agent on the mouse back skin assay. PMID:14581170

  10. Effect of rootstock on the scion of Hevea brasiliensis through metabolic analysis of latex samples by 1H NMR

    Directory of Open Access Journals (Sweden)

    Eduardo Sanches Pereira do Nascimento

    2011-01-01

    Full Text Available In this study, the effect of rootstock on grafting through metabolomic analysis of latex (Hevea brasiliensis samples was verified by 1H nuclear magnetic resonance (NMR and multivariate data analysis. Sixteen metabolites present in the latex cytosol were characterized by NMR. PCA analysis showed that the latex samples of the RR and GR groups can be differentiated. The GR group samples present a metabolic profile similar to the RR group samples, while the RG group is in an intermediate position between RR and GG groups. Sucrose and formate contributed greatly to the separation obtained by PCA, presenting a good correlation between the results. 1H NMR was an efficient technique to differentiate latex samples from different types of rootstocks and grafting and in the future could be used to predict rubber production by latex analysis.

  11. The use of liquid latex for soot removal from fire scenes and attempted fingerprint development with Ninhydrin.

    Science.gov (United States)

    Clutter, Susan Wright; Bailey, Robert; Everly, Jeff C; Mercer, Karl

    2009-11-01

    Throughout the United States, clearance rates for arson cases remain low due to fire's destructive nature, subsequent suppression, and a misconception by investigators that no forensic evidence remains. Recent research shows that fire scenes can yield fingerprints if soot layers are removed prior to using available fingerprinting processes. An experiment applying liquid latex to sooted surfaces was conducted to assess its potential to remove soot and yield fingerprints after the dried latex was peeled. Latent fingerprints were applied to glass and drywall surfaces, sooted in a controlled burn, and cooled. Liquid latex was sprayed on, dried, and peeled. Results yielded usable prints within the soot prior to removal techniques, but no further fingerprint enhancement was noted with Ninhydrin. Field studies using liquid latex will be continued by the (US) Virginia Fire Marshal Academy but it appears that liquid latex application is a suitable soot removal method for forensic applications. PMID:19732277

  12. Modeling the Adsorption of Hydrophobic Ethoxylated Urethane (HEUR) Thickeners onto Latex Surfaces using Self-Consistent Field Theory

    Science.gov (United States)

    Ginzburg, Valeriy; van Dyk, Antony; Chatterjee, Tirtha; Wang, Shihu; Larson, Ronald

    2015-03-01

    Hydrophobic Ethoxylated Urethane (HEUR) polymers are widely used as rheology modifiers (thickeners) in waterborne latex paints. Recently, it has been shown that the thickening effect of HEURs in paints is largely determined by their adsorption onto latex surfaces, this adsorption being a function of polymer structure, latex surface chemistry, and total available latex surface. Here, we describe the application of Self-Consistent Field Theory (SCFT) to calculate adsorption isotherms of several model HEURs onto ideal hydrophobic latex surfaces. Unlike earlier SCFT studies of adsorption, we explicitly take into account the role of HEUR micelles and competition between adsorption and micellization. The results are compared with experimental data and coarse-grained molecular dynamic (CG-MD) simulations, and good qualitative and semi-quantitative agreement is found. This work was supported by The Dow Chemical Company.

  13. Low field NMR study of the latex derived from Brosimum parinarioides - Moraceae

    International Nuclear Information System (INIS)

    Brosimum parinarioides is a tree found in the Amazonia forest and its latex (Leite de Amapa) is often used like food and by the popular medicine in the treatment of tuberculosis and asthma. Being swallowed in nature, its necessary determinate the stability degree of this latex in the storage conditions in which is used in Amazonia. The analyses of T2 data showed that the limit of stability is not longer than six month in the storage conditions used by the population of Amazonia. The Low field NMR proved to be an efficient method for this kind of study. (author)

  14. The design of an irradiator for the continuous processing of liquid latex

    International Nuclear Information System (INIS)

    This paper presents anew design concept for a gamma irradiation plant for the continuous processing of pumpable liquids. Typical applications of such a plant include: the irradiation vulcanisation of natural latex rubber; disinfection of municipal sewage sludge for agricultural use; sterilisation of liquids in the pharmaceutical and cosmetics industries; industrial processing of bulk liquids The authors describe the design and operation of the latex irradiator now operating on a small production scale in Malaysia and proposed developments. The design allows irradiation processing to be carried out under an inert or other gaseous environment. State-of-the-art computer control system ensures the fully automatic processing operation needed by industrial computers

  15. Radiation Vulcanization of Natural Rubber Latex (RVNRL): A Potential Material for Nuclear Power Plant Gloves

    International Nuclear Information System (INIS)

    Radiation vulcanization of natural rubber latex has great potential for the production of nuclear power plant gloves due to its low ash and mineral content. And this is in-line with the role played by Malaysian Nuclear Agency as Technical Supporting Organization for Nuclear Power Program. This paper discussed the evaluation done to determine ash content in RVNRL and SVNRL films. Both samples were prepared using casting technique and the properties were compared. Films prepared from raw latex without any vulcanizing agent were regarded as a control. (author)

  16. Trial Production of Surgical Gloves from Irradiated Natural Rubber Latex on Factory Scale

    Directory of Open Access Journals (Sweden)

    M. Utama

    2005-07-01

    Full Text Available Trial production of surgical gloves from irradiated natural rubber latex at the PT. Laxindo Utama Serang Banten glove factory has been carried out. The variation of heating temperature and leaching time during processing were evaluated. The physical and mechanical properties and the protein allergen respond of surgical gloves using ELISA method were measured. The results showed that the physical and mechanical of surgical gloves such as tensile strength, modulus, and elongation at break arefound to meet the requirements of the ISO or SNI standard for surgical gloves. While the allergic response through clinical tested latex-sensitive protein allergen known as ELISA test is found to be negative.

  17. Mechanical and morphological properties of kenaf powder filled natural rubber latex foam

    International Nuclear Information System (INIS)

    This research is carried out by incorporate kenaf powder with natural rubber latex (NRL) compound and is foamed to make natural rubber latex foam (NRLF) by using a well known technique called Dunlop method. Different loading of kenaf powder was added to NRL compound and was foamed to make NRLF. The tensile properties, and morphology of kenaf filled NRLF was studied. Increase in kenaf loading reduced the tensile strength and elongation at break and of a compound. Modulus at 100% elongation of the compound increased with increased in filler loading. The morphological and micro structural characterization has been performed by using scanning electron microscopy (SEM)

  18. Gamma irradiator design concepts for radiation vulcanisation of natural rubber latex

    International Nuclear Information System (INIS)

    Radiation vulcanisation of natural rubber latex (NRL) is a new and yet unproven technology and one which involves undefined problems of consumer acceptance and high degree of radiation risk. Therefore, the designer should take care that the initial capital cost of the plant is as low as possible to keep the unit processing cost low during the initial lean period of the product requirement by the market. Three irradiators to process natural rubber latex have been designed as per capacity requirement of the user. Their salient features are described. (author). 2 tabs., 24 figs

  19. Trial Production of Surgical Gloves from Irradiated Natural Rubber Latex on Factory Scale

    International Nuclear Information System (INIS)

    Trial production of surgical gloves from irradiated natural rubber latex at the PT. Laxindo Utama Serang Banten glove factory has been carried out. The variation of heating temperature and leaching time during processing were evaluated. The physical and mechanical properties and the protein allergen respond of surgical gloves using ELISA method were measured. The result showed that the physical and mechanical of surgical gloves such as tensile strength, modulus, and elongation at break are found to meet the requirements of the ISO or SNI standard for surgical gloves. While the allergic response through clinical tested latex-sensitive protein allergen known as ELISA test is found to be negative. (author)

  20. A Practical Guide to LaTeX Tips and Tricks

    OpenAIRE

    Merciadri, Luca

    2009-01-01

    LaTeX is a beautiful programming language. One sometimes wants to write in an easy and quick way various documents, such as letters, papers, reports, theses, and so on. Here, “one” can be a new student, an old professor, or even somebody who is not linked at all with any academic stuff. We often want special constructs in our documents. This is more difficult than basic typesetting, especially using LaTeX when you are not experienced. On one hand, scientists do not always have the time ...

  1. Mechanical and morphological properties of kenaf powder filled natural rubber latex foam

    Energy Technology Data Exchange (ETDEWEB)

    Karim, Ahmad Fikri Abdul, E-mail: a.fikri-89@yahoo.com; Ariff, Zulkifli Mohamad [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Pulau Pinang (Malaysia); Ismail, Hanafi [Cluster for Polymer Composites (CPC), Science and Engineering Research Centre, Engineering Campus, Universiti Sains Malaysia,14300 Nibong Tebal, Pulau Pinang (Malaysia)

    2015-07-22

    This research is carried out by incorporate kenaf powder with natural rubber latex (NRL) compound and is foamed to make natural rubber latex foam (NRLF) by using a well known technique called Dunlop method. Different loading of kenaf powder was added to NRL compound and was foamed to make NRLF. The tensile properties, and morphology of kenaf filled NRLF was studied. Increase in kenaf loading reduced the tensile strength and elongation at break and of a compound. Modulus at 100% elongation of the compound increased with increased in filler loading. The morphological and micro structural characterization has been performed by using scanning electron microscopy (SEM)

  2. The evolution and use of a personal LaTeX metapackage

    DEFF Research Database (Denmark)

    Andersen, Esben Sloth

    This document defines and describes esameta.sty and its variant esametaps.sty. They are personal LATEX packages that largely consist of calls of other packages. These 'metapackages' are selected to help the development of the author's complex book and paper projects-but some of his decisions might...... be of more general relevance. The use of the LATEX system of 'literate programming' and the testing the compatibility of new commands and packages with the previously included parts of the metapackage should also be noticed....

  3. DMS AND 13C NMR STUDIES ON THE COMPATIBILITY AND DYNAMICS OF LATEX BIDIRECTIONAL IPNS AND LATEX IPN OF PVA c/PBA

    Institute of Scientific and Technical Information of China (English)

    YAN Xin; XU Xiaolong; ZHANG Baozhen; YAO Shuren; QIAN Baogong

    1993-01-01

    The compatibility and dynamics of latex bidirectional interpenetrating polymer networks (LBIPNs) and latex IPN(LIPN) of poly(vinyl acetate)(PVAc) and poly (butyl acrylate )(PBA) are investigated by means of dynamic mechanical spectroscopy (DMS) and nuclear magnetic resonance (NMR) techniques. The results of DMS show that the compatibility of the LBIPNs is much better than that of the corresponding LIPN and depends to a large extent on the distribution of PVAc both in the core and in the shell. The results of NMR measurements indicate that the rotational correlation times of the side- groups of PBA in the LBIPN are longer than those in the LIPN. The relation between the 13C linewidths of PBA and temperature is also discussed.

  4. Detection of the density of fine particulate matter employing laser beam divergence and inertia-dependent particle motion

    Science.gov (United States)

    Schrobenhauser, R.; Strzoda, R.; Hartmann, A.; Fleischer, M.; Amann, M.-C.

    2014-10-01

    We present a miniaturized sensor setup capable of determining the density of airborne particles employing size information provided by an enhanced light-scattering intensity ratio technique and inertia-dependent particle motion. The method is based on the particle density-dependent spatial particle spreading, measured as the time of flight using a divergent laser beam. Measurement results using polystyrene latex and silica particles in a size range of 500-1,600 nm show good agreement with theoretical estimations.

  5. Chain Teleportation

    OpenAIRE

    Lee, Chien-er

    2004-01-01

    By means of the idea of measurements on the crossed space-time nonlocal observables, we extend the mechanism for the two-way quantum teleportation to the chain teleportation among N spatially separated spin-1/2 systems. Since in the process only the local interactions are used, the microcausality is automatically satisfied.

  6. Physical Characteristics of the Leaves and Latex of Papaya Plants Infected with the Papaya meleira Virus.

    Science.gov (United States)

    Magaña-Álvarez, Anuar; Vencioneck Dutra, Jean Carlos; Carneiro, Tarcio; Pérez-Brito, Daisy; Tapia-Tussell, Raúl; Ventura, Jose Aires; Higuera-Ciapara, Inocencio; Fernandes, Patricia Machado Bueno; Fernandes, Antonio Alberto Ribeiro

    2016-01-01

    Sticky disease, which is caused by Papaya meleira virus (PMeV), is a significant papaya disease in Brazil and Mexico, where it has caused severe economic losses, and it seems to have spread to Central and South America. Studies assessing the pathogen-host interaction at the nano-histological level are needed to better understand the mechanisms that underlie natural resistance. In this study, the topography and mechanical properties of the leaf midribs and latex of healthy and PMeV-infected papaya plants were observed by atomic force microscopy and scanning electron microscopy. Healthy plants displayed a smooth surface with practically no roughness of the leaf midribs and the latex and a higher adhesion force than infected plants. PMeV promotes changes in the leaf midribs and latex, making them more fragile and susceptible to breakage. These changes, which are associated with increased water uptake and internal pressure in laticifers, causes cell disruption that leads to spontaneous exudation of the latex and facilitates the spread of PMeV to other laticifers. These results provide new insights into the papaya-PMeV interaction that could be helpful for controlling papaya sticky disease. PMID:27092495

  7. Formation of Defect-Free Latex Films on Porous Fiber Supports

    KAUST Repository

    Lively, Ryan P.

    2011-09-28

    We present here the creation of a defect-free polyvinylidene chloride barrier layer on the lumen-side of a hollow fiber sorbent. Hollow fiber sorbents have previously been shown to be promising materials for enabling low-cost CO 2 capture, provided a defect-free lumen-side barrier layer can be created. Film experiments examined the effect of drying rate, latex age, substrate porosity (porous vs nonporous), and substrate hydrophobicity/ hydrophilicity. Film studies show that in ideal conditions (i.e., slow drying, fresh latex, and smooth nonporous substrate), a defect-free film can be formed, whereas the other permutations of the variables investigated led to defective films. These results were extended to hollow fiber sorbents, and despite using fresh latex and relatively slow drying conditions, a defective lumen-side layer resulted. XRD and DSC indicate that polyvinylidene chloride latex develops crystallinity over time, thereby inhibiting proper film formation as confirmed by SEM and gas permeation. This and other key additional challenges associated with the porous hollow fiber substrate vs the nonporous flat substrate were overcome. By employing a toluene-vapor saturated drying gas (a swelling solvent for polyvinylidene chloride) a defect-free lumen-side barrier layer was created, as investigated by gas and water vapor permeation. © 2011 American Chemical Society.

  8. Two chitinase-like proteins abundantly accumulated in latex of mulberry show insecticidal activity

    Directory of Open Access Journals (Sweden)

    Komatsu Aino

    2010-01-01

    Full Text Available Abstract Background Plant latex is the cytoplasm of highly specialized cells known as laticifers, and is thought to have a critical role in defense against herbivorous insects. Proteins abundantly accumulated in latex might therefore be involved in the defense system. Results We purified latex abundant protein a and b (LA-a and LA-b from mulberry (Morus sp. and analyzed their properties. LA-a and LA-b have molecular masses of approximately 50 and 46 kDa, respectively, and are abundant in the soluble fraction of latex. Western blotting analysis suggested that they share sequence similarity with each other. The sequences of LA-a and LA-b, as determined by Edman degradation, showed chitin-binding domains of plant chitinases at the N termini. These proteins showed small but significant chitinase and chitosanase activities. Lectin RCA120 indicated that, unlike common plant chitinases, LA-a and LA-b are glycosylated. LA-a and LA-b showed insecticidal activities when fed to larvae of the model insect Drosophila melanogaster. Conclusions Our results suggest that the two LA proteins have a crucial role in defense against herbivorous insects, possibly by hydrolyzing their chitin.

  9. Molten salt pyrolysis of latex. [synthetic hydrocarbon fuel production using the Guayule shrub

    Science.gov (United States)

    Bauman, A. J. (Inventor)

    1981-01-01

    Latex-rich plants such as Guayule or extracts thereof are pyrolyzed in an inert nitrogen atmosphere inorganic salt melts such as a LiCl/KCl eutectic at a temperature of about 500 C. The yield is over 60% of a highly aromatic, combustible hydrocarbon oil suitable for use as a synthetic liquid fuel.

  10. Radiation prevulcanized natural rubber latex: Cytotoxicity and safety evaluation on animal

    International Nuclear Information System (INIS)

    Radiation prevulcanized natural rubber latex (RVNRL) was claimed to be more user friendly than natural rubber latex prevulcanized by sulphur curing system. The absence of Type IV allergy inducing chemicals in RVNRL make it a suitable material for manufacturing of many kinds of latex products, especially those come into direct contact with users. This paper reveals and discusses the findings of cytotoxicity test and safety evaluation on animal for RVNRL. The test was done on RVNRL films prepared by coagulant dipping method and RVNRL dipped products produced by latex dipped product manufacturers. Cytotocixity test was carried out on mammalian cell culture American Type Culture Collection CCL 81, Vero. Results indicated that no cytotoxic effect from RVNRL films and products was found on the cell culture. Two animal studies, namely dermal sensitization study and primary skin irritation study, were done on gloves made from RVNRL. Albino white guinea pigs were used as test subjects in dermal sensitization study and results showed no sensitization induced by the application of test material in the guinea pigs. Primary skin irritation study was done on New Zealand white rabbits and results showed that the product tested was not corrosive and was not a primary irritant

  11. Alergia al latex en los trabajadores sanitarios (II: medidas de prevención

    Directory of Open Access Journals (Sweden)

    M. S. Gil Micharet

    2007-12-01

    Full Text Available Se presenta la segunda parte del artículo de revisión sobre alergia al látex en trabajadores sanitarios en el que se recogen las medidas de prevención.The second part of the revision article about latex allergy in the healthcare workers are presented, in which preventive measures are collected.

  12. Preparations and mechanical properties of low proteins radiation vulcanised natural rubber latex (RVNRL)

    International Nuclear Information System (INIS)

    Low proteins latex can be used in RVNRL preparation. Either Formulation Rll, uses single sensitiser or Formulation Rlll, uses a combination of sensitisers are useful in low proteins RVNRL preparation. However, these RVNRL formulations produce film vulcanisates of different mechanical properties and accelerated ageing resistance

  13. Radiation vulcanization of natural rubber latex with low energy accelerator-II

    International Nuclear Information System (INIS)

    The natural rubber latex (NRL) was radiation vulcanized under a low energy electron accelerator. Accelerating voltage and maximum beam current of this accelerator are 250 kV and 10 mA respectively. Irradiation was carried out in a reaction vessel with constant stirring. The capacity of the vessel is 18 liters. Radiation vulcanization accelerators (RVA) were normal butyl acrylate (n-BA) and nonane-diol-diacrylate (NDDA). NDDA has no bad smell like that of n-BA. 20 minutes irradiation time is enough to vulcanize 14 liters of latex when 5 phr RVA (both types) are used. Maximum of ∼30 MPa tensile strength was obtained with 5 phr NDD-A. However the remained NDDA is difficult to remove due to high molecular weight. Water-extractable proteins content was determined in dipped films for various leaching conditions without and with additive (polyvinyl alcohol, PVA). Water extractable proteins content is reduced to ≤ 41 by adding 5 phr PVA and leaching for 8 hours. The tackiness of the dipped films is reduced to 0.1 from 9 gf by mixing 6 phr PVA with the irradiated latex. Hand gloves (surgical and examination) were successfully produced from the irradiated latex. (author)

  14. Marketing techniques and cost calculations of radiation vulcanised natural rubber latex (RVNRL)

    International Nuclear Information System (INIS)

    This paper describes how RVNRL is promoted to the latex based industries locally and abroad. RVNRL promotion requires patience and very challenging. This is a fact since the product is new to the market. Cost is important in deciding its market and potential usage. The elements that contribute to the cost is described in this paper. (Author)

  15. Secretory Duct Structure and Phytochemistry Compounds of Yellow Latex in Mangosteen Fruit

    Directory of Open Access Journals (Sweden)

    DORLY

    2008-09-01

    Full Text Available Yellow latex is the main problem in mangosteen agribusiness, because it is one factor lowering the fruit quality. The structure of yellow latex secretory ducts in the flower and fruit as well as in the root, stem and leaf of mangosteen (Garcinia mangostana L. seedling and the qualitative phytochemistry of yellow latex were studied. The ducts were branched, canal-like type. They were found in the exocarp, mesocarp, endocarp, aril of the fruit, flower, stem, and leaf. In the fruit, the biggest diameter of the secretory ducts was found in the endocarp. There were continuous secretory ducts from fruit stalk to the fruit. Ultrastructural observation showed that the ducts surrounded by specific epithelial cells, which were living cells containing dense cytoplasm with plastid, mitochondria and golgi apparatus organelles. The qualitative test indicated that the yellow latex collected from stem bark, outer part of fruit, young fruit pericarp, mature aril and young aril contained terpenoid, flavonoid and tannin, but not alkaloid, saponin and steroid, except in the young aril containing the steroid.

  16. Insights on the Phytochemical Profile (Cyclopeptides and Biological Activities of Calotropis procera Latex Organic Fractions

    Directory of Open Access Journals (Sweden)

    Thiago Lustosa Jucá

    2013-01-01

    Full Text Available Calotropis procera is a medicinal plant whose pharmacological properties are associated with its latex. Here, the Calotropis procera latex fractions were investigated in an attempt to trace its phytochemical profile and measure its anti-inflammatory and toxicity activity. The crude latex was partitioned, yielding five fractions (49.4% hexane, 5.2% dichloromethane, 2.0% ethyl acetate, 2.1% n-butanol, and 41.1% aqueous. Phytochemical screening and spectroscopy analysis revealed that dichloromethane is the most chemically diverse fraction. Triterpenes were detected in both the hexane and dichloromethane fractions, while flavonoids were detected in the dichloromethane and ethyl acetate fractions. These fractions were cytotoxic to cancer cell lines (LD50 0.05 to 3.9 μg/mL and lethal to brine shrimp (LD50 10.9 to 65.7 μg/mL. Reduced neutrophil migration in rats was observed in carrageenan-induced peritonitis for the dichloromethane (67%, ethyl acetate (56%, and aqueous (72% fractions. A positive reaction with tolidine and ninhydrin suggested that cyclopeptides are in the ethyl acetate fraction. It is therefore concluded that Calotropis procera latex dichloromethane and ethyl acetate fractions exhibit both in vitro and in vivo activities as well as anti-inflammatory properties. Cyclopeptide detection is especially interesting because previous attempts to investigate these low-molecular cyclic amino acid sequences in C. procera have failed.

  17. Enhancing Student Writing and Computer Programming with LATEX and MATLAB in Multivariable Calculus

    Science.gov (United States)

    Sullivan, Eric; Melvin, Timothy

    2016-01-01

    Written communication and computer programming are foundational components of an undergraduate degree in the mathematical sciences. All lower-division mathematics courses at our institution are paired with computer-based writing, coding, and problem-solving activities. In multivariable calculus we utilize MATLAB and LATEX to have students explore…

  18. Physical Characteristics of the Leaves and Latex of Papaya Plants Infected with the Papaya meleira Virus

    Directory of Open Access Journals (Sweden)

    Anuar Magaña-Álvarez

    2016-04-01

    Full Text Available Sticky disease, which is caused by Papaya meleira virus (PMeV, is a significant papaya disease in Brazil and Mexico, where it has caused severe economic losses, and it seems to have spread to Central and South America. Studies assessing the pathogen-host interaction at the nano-histological level are needed to better understand the mechanisms that underlie natural resistance. In this study, the topography and mechanical properties of the leaf midribs and latex of healthy and PMeV-infected papaya plants were observed by atomic force microscopy and scanning electron microscopy. Healthy plants displayed a smooth surface with practically no roughness of the leaf midribs and the latex and a higher adhesion force than infected plants. PMeV promotes changes in the leaf midribs and latex, making them more fragile and susceptible to breakage. These changes, which are associated with increased water uptake and internal pressure in laticifers, causes cell disruption that leads to spontaneous exudation of the latex and facilitates the spread of PMeV to other laticifers. These results provide new insights into the papaya-PMeV interaction that could be helpful for controlling papaya sticky disease.

  19. Physical Characteristics of the Leaves and Latex of Papaya Plants Infected with the Papaya meleira Virus

    Science.gov (United States)

    Magaña-Álvarez, Anuar; Vencioneck Dutra, Jean Carlos; Carneiro, Tarcio; Pérez-Brito, Daisy; Tapia-Tussell, Raúl; Ventura, Jose Aires; Higuera-Ciapara, Inocencio; Fernandes, Patricia Machado Bueno; Fernandes, Antonio Alberto Ribeiro

    2016-01-01

    Sticky disease, which is caused by Papaya meleira virus (PMeV), is a significant papaya disease in Brazil and Mexico, where it has caused severe economic losses, and it seems to have spread to Central and South America. Studies assessing the pathogen-host interaction at the nano-histological level are needed to better understand the mechanisms that underlie natural resistance. In this study, the topography and mechanical properties of the leaf midribs and latex of healthy and PMeV-infected papaya plants were observed by atomic force microscopy and scanning electron microscopy. Healthy plants displayed a smooth surface with practically no roughness of the leaf midribs and the latex and a higher adhesion force than infected plants. PMeV promotes changes in the leaf midribs and latex, making them more fragile and susceptible to breakage. These changes, which are associated with increased water uptake and internal pressure in laticifers, causes cell disruption that leads to spontaneous exudation of the latex and facilitates the spread of PMeV to other laticifers. These results provide new insights into the papaya-PMeV interaction that could be helpful for controlling papaya sticky disease. PMID:27092495

  20. The Condom Conundrum: Apply Peer Pressure, Not Latex, against Casual Sex.

    Science.gov (United States)

    Delattre, Edwin J.

    1992-01-01

    If saving lives were our only moral concern, distributing condoms in schools is not the best way to proceed. Abstinence has greater life-saving power than any piece of latex. School condom distribution promotes casual, promiscuous sex, ignores this contraceptive's failure rate, and runs counter to sound educational policy. Deferred gratification…

  1. Decrease in the rate of sensitization and clinical allergy to natural rubber latex

    DEFF Research Database (Denmark)

    Blaabjerg, Michelle S B; Andersen, Klaus E; Bindslev-Jensen, Carsten;

    2015-01-01

    BACKGROUND: In the 1980s, a striking increase in natural rubber latex (NRL) allergy was seen. Since then, many measures have been taken to prevent NRL allergy. OBJECTIVES: To investigate changes in the prevalence of NRL sensitization/clinical NRL allergy over time from 2002 to 2013. METHODS: All...

  2. New approach for papaya latex storage without virus degradation Nova metodologia de armazenamento do latex de mamão sem degradação viral

    Directory of Open Access Journals (Sweden)

    Silas P. Rodrigues

    2009-03-01

    Full Text Available Papaya meleira virus (PMeV is the causal agent of papaya (Carica papaya L. sticky disease, which has been detected through analysis of its double-stranded RNA (dsRNA genome from plant latex. In this work we demonstrate that PMeV dsRNA is protected during 25 days when latex is diluted in citrate buffer pH 5.0 (1:1 v/v and maintained at -20°C. At the same temperature, some protection was observed for pure latex or latex diluted in ultra-pure water. Conversely, the dsRNA was almost completely degraded after 25 days when maintained at 25°C, indicating the need for freezing. The proper procedures to collect and store papaya latex described here will contribute to efficient and large scale use of molecular diagnosis of PMeV.Papaya meleira virus (PMeV é o agente etiológico da meleira do mamoeiro (Carica papaya L., cujo diagnóstico é feito através da detecção do RNA dupla-fita (dsRNA viral a partir do látex das plantas. Neste trabalho é demonstrado que o dsRNA do PMeV é protegido durante 25 dias quando diluído em tampão citrato pH 5.0 (1:1 v/v seguido de armazenamento à -20°C. Nesta mesma temperatura, o dsRNA foi parcialmente protegido quando o látex foi diluído em água ultra-pura ou mantido puro. Ao contrário, quando as amostras foram mantidas à 25°C, observou-se uma degradação progressiva do dsRNA, com ausência de bandas após 25 dias, indicando a necessidade do congelamento do látex. Os procedimentos de coleta e armazenamento do látex descritos neste trabalho contribuem para a eficiência e uso em larga escala do diagnóstico molecular do PMeV.

  3. Label-free quantitative proteomics reveals differentially regulated proteins in the latex of sticky diseased Carica papaya L. plants.

    Science.gov (United States)

    Rodrigues, Silas P; Ventura, José A; Aguilar, Clemente; Nakayasu, Ernesto S; Choi, HyungWon; Sobreira, Tiago J P; Nohara, Lilian L; Wermelinger, Luciana S; Almeida, Igor C; Zingali, Russolina B; Fernandes, Patricia M B

    2012-06-18

    Papaya meleira virus (PMeV) is so far the only described laticifer-infecting virus, the causal agent of papaya (Carica papaya L.) sticky disease. The effects of PMeV on the laticifers' regulatory network were addressed here through the proteomic analysis of papaya latex. Using both 1-DE- and 1D-LC-ESI-MS/MS, 160 unique papaya latex proteins were identified, representing 122 new proteins in the latex of this plant. Quantitative analysis by normalized spectral counting revealed 10 down-regulated proteins in the latex of diseased plants, 9 cysteine proteases (chymopapain) and 1 latex serine proteinase inhibitor. A repression of papaya latex proteolytic activity during PMeV infection was hypothesized. This was further confirmed by enzymatic assays that showed a reduction of cysteine-protease-associated proteolytic activity in the diseased papaya latex. These findings are discussed in the context of plant responses against pathogens and may greatly contribute to understand the roles of laticifers in plant stress responses. PMID:22465191

  4. Dielectrophoretic behavior of latex nanospheres: Low-frequency dispersion

    OpenAIRE

    Hughes, MP

    2002-01-01

    The electrostatic manipulation of nanoparticles using nonuniform electric fields (dielectrophoresis) has proved a useful method of investigating the movement of charge around colloidal particles. While previous work has explained many of the ways in which particle behavior deviates from that predicted by classical Maxwell-Wagner interfacial polarization theory, there exists an additional, anomalous polarization mechanism observed in media of high conductivity, causing an unexpected observatio...

  5. Hydrogen transfer hydrocracking of C. procera latex under ambient pressure conditions to get value added chemicals and fuels

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, D.K.; Behera, B.K.; Arora, M. (Indian Institute of Technology, New Delhi (India). Fuels and Biofuels Engineering Lab.)

    1994-01-01

    Biomass is renewable source of energy while the reserves of petroleum are being depleted. The latex of a potential petrocrop, Calotropis procera, a laticifer, arid-plant which is rich in hydrocarbon type triterpene compounds etc. was found to be a better feed stock for thermal hydrocracking as compared to whole plant biomass in terms of liquid product yield. Studies of chemical reaction dynamics of the thermal cracking of latex at 200-400[degree]C showed that the process should be termed as hydrogen-transfer (H-T) hydrocracking of latex under ambient pressure conditions. The hydrogen rich cracked triterpenoids act as the H-donors in this process, where nascent hydrogen atoms and free radicals chemically plug the cracked moieties to stabilise these. Latex was also coagulated and the H-T hydrocracking of the feedstock coagulum gave a higher yield of cracked oil in comparison to that from the dried latex. The temperature for hydrocracking of latex has been optimized to 350[degree]C and molecular sieve was found to catalyse the H-T hydrocracking process to yield more liquid product. The distillation range of cracked latex oil (CLO) obtained from H-T hydrocracking of C. procera latex indicated that it can be used as fuel oil or substitute for diesel fuel. Moreover, CLO resembled diesel fuels and was predominantly paraffinic in nature as characterised by NMR and FTIR spectral analysis. A process has been recommended for getting value added fuels and chemicals from C. procera latex. 29 refs., 5 figs., 3 tabs.

  6. Toxicity of Euphorbia milii latex and niclosamide to snails and nontarget aquatic species.

    Science.gov (United States)

    Oliveira-Filho, E C; Paumgartten, F J

    2000-07-01

    The toxicity of Euphorbia milii molluscicidal latex and niclosamide (NCL) to target snails (Biomphalaria glabrata and Biomphalaria tenagophila) and nontarget aquatic organisms is evaluated. Planorbidae snails were killed by very low concentrations of lyophilized latex (48-h LC(50), mg/L: B. glabrata, 0.12; B. tenagophila, 0.09; Helisoma duryi, 0.10). Latex was less toxic (48-h LC(50) or EC(50), mg/L) to oligochaeta (Tubifex tubifex, 0.31), planktonic crustacea (Daphnia similis, 0.38; C. dubia, 1.07; Artemia sp., 0.93), and fishes (Danio rerio, 0.96; Poecilia reticulata, 1. 39), and considerably less toxic to Ampullariidae snails (Pomacea sp. , 10.55) and frog tadpoles (Rana catesbeiana, 7.50). Latex (up to 100 mg/L) was not toxic to bacteria (P. putida and V. fischeri), algae (Selenastrum capricornutum and Chlorella vulgaris), and mosquito larvae (Anopheles albitarsis, Aedes aegypti, Aedes fluviatilis). NCL was very toxic (48-h LC(50) or EC(50), mg/L) to Planorbidae snails (B. glabrata, 0.15, B. tenagophila, 0.13; H. duryi, 0.10), T. tubifex (0.11), crustacea (D. similis, 0.19; Ceriodaphnia dubia, 0.47; Artemia sp. 0.18), fishes (D. rerio, 0.25; P. reticulata, 0.29), R. catesbeiana (0.16), and Pomacea sp. (0.76). NCL was toxic to bacteria, algae (96-h IC(50), mg/L: S. capricornutum, 0.34; C. vulgaris, 1.23) and slightly toxic to mosquito larvae. In conclusion, E. milii latex, as compared with the reference molluscicide niclosamide, presents a higher degree of selectivity toward snails which are intermediate hosts of Schistosoma trematodes. PMID:10903832

  7. Pilot Scale Production of Irradiated Natural Rubber Latex and its Dipping Products

    Directory of Open Access Journals (Sweden)

    M. Utama

    2005-07-01

    Full Text Available One hundred and fifty kg natural rubber latex (NRL before and after concentration were added with 3 phr (part hundred ratio of rubber normal butyl acrylate, then the mixture were irradiated at 25 kGy by gamma rays of 60Co in pilot scale. The irradiated natural rubber latex (INRL were then being to use for producing rubber products such as condom, surgical gloves, and spygmomanometer in factory scale. The quality of INRL and rubber products such as : total solid content (TSC, dry rubber content (DRC, KOH, VFA and MST number, tensile strength, modulus, elongation at break, extractable protein content, and response against Type I allergy etc. were evaluated. The economic aspect for producing INRL by means of Gamma Irradiator (GI and Electron Beam Machine (EBM such as payback period (PP, net present value (NPV and internal rate return (IRR were calculated. The results showed that the latex properties of INRL such as DRC, TSC, KOH, VFA, and MST number are not only found to the requirement of the ISO 2004 standard but also the latex has low protein, lipid, and carbohydrate content. The physical and mechanical properties (tensile strength, modulus, and elongation at break of rubber dipping products such as condom, gloves, and sphygmomanometer are not only found to the requirement of ISO 4074, ISO 10282, and ANSI/AAMI SP-1994 standards, but also the allergic response tested clinical latex-sensitive protein allergen by ELISA test on gloves, and by SPT test on condom are found to be negative. It indicates that production of INRL or PVNRL or RVNRL by EBM 250 keV/10 mA, was more cheap than by using gamma γ irradiator 200 kCi, or sulfur vulcanization. The value of PBP (payback period was 2,1 years, NPV (net present value was 4,250 US $, PI (profitability index 1,06 and IRR (internal rate of returns was 25,0%.

  8. Development of condom and gloves from radiation vulcanized natural rubber latex

    International Nuclear Information System (INIS)

    Study on radiation vulcanisation of natural rubber (NR) had been carried out since early of 1970. The positive result guided it to the establishment of a latex irradiator in 1983. This installation was designed for studying the economic aspect of radiation vulcanised of natural rubber latex (RVNRL), as well as for training and demonstration. After years of experiences in using that installation, it appeared that a lot of improvement should be done before transfering that technology to industry. Further development being done and a significant success has been achieved: characteristic of NR latex, antioxidant for RVNRL, new sensitizer, and cost analysis of RVNRL. A combination of n-BA and CCl4 or n-BA alone showing a promising new sensitizer, which will be able in reducing the irradiation cost of NR latex. In order to introduce this technology to rubber gloves industry, a study of producing rubber gloves from RVNRL, a survey of the consumption of rubber gloves by the Hospital in Indonesia, and personal contact with rubber gloves industries have been done. The physical properties of rubber gloves prepared from RVNRL was reported to meet the Indonesian Standard of Industry. A comparison study with conventional sulfur vulcanisation has been done using the same of NR latex. According to the survey, the consumption of rubber gloves in the Hospital throughout Indonesia was about 3.5 million pairs, in with each pair was used for several times. A number of new rubber gloves companies which was established in this year (1989) was directed to meet the world consumption of examination rubber gloves. The total estimated capacity was about 1000 million/year. Several of those companies having a formal co-operation with BATAN in the development of the application of RVNRL. (author)

  9. Pilot Scale Production of Irradiated Natural Rubber Latex and Its Dipping Products

    International Nuclear Information System (INIS)

    One hundred and fifty kg natural rubber latex (NRL) before and after concentration were added with 3 phr (part hundred ratio of rubber) normal butyl acrylate, then the mixture were irradiated at 25 kGy by gamma rays of 60Co in pilot scale. The irradiated natural rubber latex (INRL) were then being to use for producing rubber products such as condom, surgical gloves, and sphygmomanometer in factory scale. The quality of INRL and rubber products such as : total solid content (TSC), dry rubber content (DRC), KOH, VFA and MST number, tensile strength, modulus, elongation at break, extractable protein content, and response against Type I allergy etc. were evaluated. The economic aspect for producing INRL by means of Gamma Irradiator (GI) and Electron Beam Machine (EBM) such as payback period (PP), net present value (NPV) and internal rate return (IRR) were calculated. The results showed that the latex properties of INRL such as DRC, TSC, KOH, VFA, and MST number are not only found to the requirement of the ISO 2004 standard but also the latex has low protein, lipid, and carbohydrate content. The physical and mechanical properties (tensile strength, modulus, and elongation at break) of rubber dipping products such as condom, gloves, and sphygmomanometer are not only found to the requirement of ISO 4074, ISO 10282, and ANSI/AAMI SP-1994 standards, but also the allergic response tested clinical latex-sensitive protein allergen by ELISA test on gloves, and by SPT test on condom are found to be negative. It indicates that production of INRL or PVNRL or RVNRL by EBM 250 keV/10 mA, was more cheap than by using gamma γ irradiation 200 kCi, or sulfur vulcanization. The value of PBP (payback period) was 2.1 years, NPV (net present value) was 4,250 US $, PI (profitability index) 1.06 and IRR (internal rate of returns) was 25.0%. (author)

  10. Isolation and partial characterization of a D-galactose-binding lectin from the latex of Synadenium carinatum

    Directory of Open Access Journals (Sweden)

    Maria Aparecida Souza

    2005-09-01

    Full Text Available A lectin from the latex of Synadenium carinatum was purified by affinity chromatography on immobilized-D-galactose-agarose and shown to be a potent agglutinin of human erythrocytes. The haemagglutination of human red cells was inhibited by 3.0 mM N-acetyl-D-galactopyranoside, 6.3 mM methyl-beta-D-galactopyranoside, 50 mM methyl-alpha-D-galactopyranoside and 50 mM D-fucose but not by L-fucose, demonstrating an anomeric and a conformational specificity. According to SDS-PAGE analysis, the lectin appeared to be a glycoprotein composed of two polypeptide chains of ca. 28 and 30 kDa, but size exclusion chromatography (Sephadex G-100 and native PAGE revealed a protein of apparent molecular weight 120 - 130 kDa made up of 28 and 30 kDa subunits. The lectin was stable in the range pH 6 - 9, and 4 - 56ºC. The N-terminal sequence of the 30 kDa subunit contained the conserved consensus sequence GPN observed in other D-galactose-binding lectins found in latex of members of the Euphorbiaceae.No presente trabalho, foi purificada por cromatografia de afinidade em D-galactose imobilizada em agarose, uma lectina do latex de Synadenium carinatum (ScLL. Essa lectina é uma potente aglutinina para eritrócitos humanos, cuja atividade hemaglutinante foi inibida com 3,0 mM de N acetil-D-galactopiranosidio, 6,3 mM de metil-beta-D-galactopiranosidio ou 50 mM metil-alfa-D-pironosidio ou D-fucose, porém, nenhuma inibição foi evidenciada por L-fucose, revelando uma especificidade anomérica e conformacional da lectina. A análise por SDS-PAGE dessa lectina pareceu ser uma glicoproteína composta por duas cadeias polipeptídicas de aproximadamente 28 e 30 kDa, porém, em cromatografia de exclusão por tamanho sobre Sephadex G100 e em gel nativo apresentou um peso molecular aparente de 120-130 kDa, a qual mostrou ser composta de uma mistura de subunidades de peptídeos de 28 e 30 kDa. Essa lectina manteve-se estável em pH de 6 a 9 e temperatura de 4 a 56ºC. A seq

  11. Whole-Chain Tick Saliva Proteins Presented on Hepatitis B Virus Capsid-Like Particles Induce High-Titered Antibodies with Neutralizing Potential.

    Directory of Open Access Journals (Sweden)

    Philipp Kolb

    Full Text Available Ticks are vectors for various, including pathogenic, microbes. Tick saliva contains multiple anti-host defense factors that enable ticks their bloodmeals yet also facilitate microbe transmission. Lyme disease-causing borreliae profit specifically from the broadly conserved tick histamine release factor (tHRF, and from cysteine-rich glycoproteins represented by Salp15 from Ixodes scapularis and Iric-1 from Ixodes ricinus ticks which they recruit to their outer surface protein C (OspC. Hence these tick proteins are attractive targets for anti-tick vaccines that simultaneously impair borrelia transmission. Main obstacles are the tick proteins´ immunosuppressive activities, and for Salp15 orthologs, the lack of efficient recombinant expression systems. Here, we exploited the immune-enhancing properties of hepatitis B virus core protein (HBc derived capsid-like particles (CLPs to generate, in E. coli, nanoparticulate vaccines presenting tHRF and, as surrogates for the barely soluble wild-type proteins, cysteine-free Salp15 and Iric-1 variants. The latter CLPs were exclusively accessible in the less sterically constrained SplitCore system. Mice immunized with tHRF CLPs mounted a strong anti-tHRF antibody response. CLPs presenting cysteine-free Salp15 and Iric-1 induced antibodies to wild-type, including glycosylated, Salp15 and Iric-1. The broadly distributed epitopes included the OspC interaction sites. In vitro, the anti-Salp15 antibodies interfered with OspC binding and enhanced human complement-mediated killing of Salp15 decorated borreliae. A mixture of all three CLPs induced high titered antibodies against all three targets, suggesting the feasibility of combination vaccines. These data warrant in vivo validation of the new candidate vaccines´ protective potential against tick infestation and Borrelia transmission.

  12. Catch Chain

    OpenAIRE

    Talbert, Robert

    2010-01-01

    Catch Chain is a book of poems that traces the journey of a Corrections Officer who attempts to combat issues of isolation, inhumane treatment of inmates and societal rejection in jails by embarking upon a cross-country road trip. However, the same issues the officer initially wrestled with begin cropping up in different cities, on various highways and in a multitude of states. The excitement and adventure of the open road runs parallel to the recurring imprisonment of the guard's mind.

  13. Study of the embryofeto-toxicity of Crown-of-Thorns (Euphorbia milii) latex, a natural molluscicide

    OpenAIRE

    Souza C.A.M.; de-Carvalho R.R.; Kuriyama S.N.; Araujo I.B.; Rodrigues R.P.; Vollmer R.S.; E.N. Alves; Paumgartten F.J.R.

    1997-01-01

    The crude latex of Crown-of-Thorns (Euphorbia milii var. hislopii) is a potent plant molluscicide and a promising alternative to the synthetic molluscicides used in schistosomiasis control. The present study was undertaken to investigate the embryofeto-toxic potential of E. milii latex. The study is part of a comprehensive safety evaluation of this plant molluscicide. Lyophilized latex (0, 125, 250 and 500 mg/kg body weight) in corn oil was given by gavage to Wistar rats (N = 100) from days 6...

  14. Label-free quantitative proteomics reveals differentially regulated proteins in the latex of sticky diseased Carica papaya L. plants

    OpenAIRE

    Silas P. Rodrigues; José A. Ventura; Aguilar, Clemente; Nakayasu, Ernesto S; Choi, Hyungwon; Sobreira, Tiago J. P.; Nohara, Lilian L.; Wermelinger, Luciana S.; Almeida, Igor C.; Zingali, Russolina B.; Fernandes, Patricia M. B.

    2012-01-01

    Papaya meleira virus (PMeV) is so far the only described laticifer-infecting virus, the causal agent of papaya (Carica papaya L.) sticky disease. The effects of PMeV on the laticifers’ regulatory network were addressed here through the proteomic analysis of papaya latex. Using both 1-DE- and 1D-LC-ESI-MS/MS, 160 unique papaya latex proteins were identified, representing 122 new proteins in the latex of this plant. Quantitative analysis by normalized spectral counting revealed 10 down-regulate...

  15. Effect of Hevea brasiliensis latex sap gel on healing of acute skin wounds induced on the back of rats

    OpenAIRE

    Maria Vitória Carmo Penhavel; Victor Henrique Tavares; Fabiana Pirani Carneiro; João Batista de Sousa

    2016-01-01

    Objective : to evaluate the effect of topical delivery of latex cream-gel in acute cutaneous wounds induced on the back of rats. Methods : we subjected sixteen rats to dermo-epidermal excision of a round dorsal skin flap, with 2.5cm diameter. We divided the animals into two groups: Latex Group: application of cream-gel-based latex throughout the wound bed on postoperative days zero, three, six and nine; Control group: no treatment on the wound. Photographs of the lesions were taken on the pr...

  16. Study of the extraction process of papain from latex of papaya (carica papaya l.) fruits cv. maradol

    OpenAIRE

    Andrade Mahecha, Margarita M; Morales Rodríguez, Olga; Martínez Correa, Hugo A.

    2012-01-01

    In this work, we studied the extraction process of papain, present in the latex of papaya fruit (Carica papaya L.) cv. Maradol.  The variables studied in the extraction of papain were: latex:alcohol ratio (1:2.1 and 1:3) and drying method (vacuum and refractance window).  Papain enzyme responses were obtained in terms of enzymatic activity and yield of the extraction process. The best result in terms of enzyme activity and yield was obtained by vacuum drying and a latex:alcohol ratio of 1:3. ...

  17. Fabrication of grating-like polystyrene latex monolayer structure as three-dimensional calibration standards for scanning probe microscope

    Institute of Scientific and Technical Information of China (English)

    Zhu Guo-Dong; Zeng Zhi-Gang; Guo Zhang; Du Qiang-Guo; Yan Xue-Jian

    2009-01-01

    This paper illuminates the preparation of grating-like polystyrene latex monolayer structure, which can minimize the effects of the size deviation of spheres and the defect transfer on the accuracy as calibration samples for micro-scopes. The latex films are grown on freshly cleaved mica substrates by vertical deposition method. The concentration dependence of the structure and the topography of latex films is characterized by optical microscope, ultraviolet-visible transmission spectrum and scanning probe microscope. The origination of such a grating-like structure is also discussed.

  18. Linear chains and chain-like fractals from electrostatic heteroaggregation.

    Science.gov (United States)

    Kim, Anthony Y; Hauch, Kip D; Berg, John C; Martin, James E; Anderson, Robert A

    2003-04-01

    The internal structure of materials prepared by aggregation of oppositely charged polystyrene spheres (electrostatic heteroaggregation) is investigated by static light scattering, optical microscopy, and Brownian dynamics simulation. Light scattering indicates ultralow mass fractal dimensions, as low as 1.2. Such low fractal dimensions, approaching the theoretical limit of a linear object, imply a chaining mechanism. Optical micrographs reveal linear chains with the particle charge alternating down the chains. Brownian dynamics simulation gives additional support for a chaining mechanism. For the polystyrene system (120-nm primary particle diameters), the fractal dimension is found to increase from 1.2 to 1.7 as the background electrolyte is increased. In terms of electrostatic screening, the results match those reported recently for larger polystyrene spheres. The low fractal dimensions appear to represent a crossover from linear chains to a structure of diffusion-limited aggregates; however, experiments under density-neutral conditions imply that sedimentation plays an important role in the formation of ultralow fractal dimensions. The practical implication is that microcomposites with a locally uniform distribution of starting materials and almost any degree of branching can be prepared from oppositely charged particles. PMID:12742045

  19. Green synthesis of silver nanoparticles using latex extract of Thevetia peruviana: a novel approach towards poisonous plant utilization

    Science.gov (United States)

    Nyoman Rupiasih, N.; Aher, Avinash; Gosavi, Suresh; Vidyasagar, P. B.

    2013-04-01

    The development of green synthesis of nanoparticles has received increasing attention due to ease of preparation, less chemical handling, and eco-friendly. In the present study, silver nanoparticles (AgNPs) were successfully synthesized from AgNO3 through a simple green synthesis route using the latex of Thevetia peruviana as reducing as well as capping agent. Synthesized silver nanoparticles were characterized using UV-vis, FTIR, SEM-EDS, XRD and HRTEM. UV-vis spectra showed absorption at 570 nm with shoulder at 395 nm. FTIR spectra analysis confirmed the functional groups involved in the AgNPs formation. X-ray diffraction pattern of AgNPs exhibited the diffraction at 2θ = 34.48°, 40.12° and 45.39° corresponding to (222), (400), and (420) Braggs reflection planes of silver nanoparticles. TEM analysis showed the particles size is spherical in nature with its size distribution between 10-30 nm. The HRTEM image showed 2.59Å interplaner spacing.

  20. Green synthesis of silver nanoparticles using latex extract of Thevetia peruviana: a novel approach towards poisonous plant utilization

    International Nuclear Information System (INIS)

    The development of green synthesis of nanoparticles has received increasing attention due to ease of preparation, less chemical handling, and eco-friendly. In the present study, silver nanoparticles (AgNPs) were successfully synthesized from AgNO3 through a simple green synthesis route using the latex of Thevetia peruviana as reducing as well as capping agent. Synthesized silver nanoparticles were characterized using UV-vis, FTIR, SEM-EDS, XRD and HRTEM. UV-vis spectra showed absorption at 570 nm with shoulder at 395 nm. FTIR spectra analysis confirmed the functional groups involved in the AgNPs formation. X-ray diffraction pattern of AgNPs exhibited the diffraction at 2θ = 34.48°, 40.12° and 45.39° corresponding to (222), (400), and (420) Braggs reflection planes of silver nanoparticles. TEM analysis showed the particles size is spherical in nature with its size distribution between 10–30 nm. The HRTEM image showed 2.59Å interplaner spacing.

  1. Luminescence and antibacterial studies of silver nanoparticles using the esterases-containing latex of E. Tirucalli plant via green route

    Science.gov (United States)

    Sudheerkumar, K. H.; Dhananjaya, N.; Reddy Yadav, L. S.

    2016-04-01

    Silver nanoparticles (Ag NPs) synthesized from silver nitrate solutions using the esterase-containing latex of the E. Tirucalli plant widely found in a large region in Karnataka, India. Plant-mediated synthesis of nanoparticles is a green chemistry approach that intercom-nects nanotechnology and plant biotechnology. The effect of extract concentration, contact time, and temperature on the reaction rate and the shape of the Ag nanoparticles was investigated. The nanoparticles have been characterized by powder X-ray diffraction, UV-visible spectroscopy, photoluminescence spectroscopy and morphology by scanning electron microscope, transmission electron microscopy, as a function of the ratio of silver ions to reducing agent molecules. Powder X-ray diffraction patterns show that the crystal structure obtained is face-centered cubic (fcc). The morphology of the silver nanoparticle was uniform with well-distributed elliptical particles with a range from 15 to 25nm. Ag NPs exhibit significant antibacterial activity against Bacillus cereus using the agar well diffusion method.

  2. The effect of storage on the content of protein in RVNRL produced in different batches of latex production

    International Nuclear Information System (INIS)

    Life-threatening latex allergy caused by latex proteins has emerged as a serious problem for health care workers and others who use latex products. This study was aimed to determine the effect of storage on the protein content of radiation prevulcanized natural rubber latex (RVNRL) produced at pilot plant scale in RAYMINTEX plant, Malaysian Nuclear Agency. Rubber films were prepared from three batches of RVNRL by coagulant dipping method and their protein content was determine by extraction using phosphate buffer solution (PBS) and measurement using Micro BCA Protein Assay Kit. Within seven months of storage period employed in this study, it was found that protein content of RVNRL reduced with storage time. (Author)

  3. The occurrence of axial latex tubes in the secondary xylem of some species of Artocarpus J. R. & G. Forster (Moraceae)

    OpenAIRE

    Topper, S.M.C.; Koek-Noorman, J.

    1980-01-01

    In a number of species of Artocarpus J.R. & G. Forster (Moraceae) laticifers were not only observed as radial tubes, enclosed in the ray tissue, but also as axial tubes, enclosed in the fibre tissue. Both types of latex tubes are connected and considered as one branched laticiferous system. A detailed description of the individual latex tubes and the whole system, based on light microscopic and scanning electron microscopic observation, is presented.

  4. Carbon isotope composition of latex does not reflect temporal variations of photosynthetic carbon isotope discrimination in rubber trees (Hevea brasiliensis).

    Science.gov (United States)

    Kanpanon, Nicha; Kasemsap, Poonpipope; Thaler, Philippe; Kositsup, Boonthida; Gay, Frédéric; Lacote, Régis; Epron, Daniel

    2015-11-01

    Latex, the cytoplasm of laticiferous cells localized in the inner bark of rubber trees (Hevea brasiliensis Müll. Arg.), is collected by tapping the bark. Following tapping, latex flows out of the trunk and is regenerated, whereas in untapped trees, there is no natural exudation. It is still unknown whether the carbohydrates used for latex regeneration in tapped trees is coming from recent photosynthates or from stored carbohydrates, and in the former case, it is expected that latex carbon isotope composition of tapped trees will vary seasonally, whereas latex isotope composition of untapped trees will be more stable. Temporal variations of carbon isotope composition of trunk latex (δ(13)C-L), leaf soluble compounds (δ(13)C-S) and bulk leaf material (δ(13)C-B) collected from tapped and untapped 20-year-old trees were compared. A marked difference in δ(13)C-L was observed between tapped and untapped trees whatever the season. Trunk latex from tapped trees was more depleted (1.6‰ on average) with more variable δ(13)C values than those of untapped trees. δ(13)C-L was higher and more stable across seasons than δ(13)C-S and δ(13)C-B, with a maximum seasonal difference of 0.7‰ for tapped trees and 0.3‰ for untapped trees. δ(13)C-B was lower in tapped than in untapped trees, increasing from August (middle of the rainy season) to April (end of the dry season). Differences in δ(13)C-L and δ(13)C-B between tapped and untapped trees indicated that tapping affects the metabolism of both laticiferous cells and leaves. The lack of correlation between δ(13)C-L and δ(13)C-S suggests that recent photosynthates are mixed in the large pool of stored carbohydrates that are involved in latex regeneration after tapping. PMID:26358051

  5. Preliminary observations on the use of latex agglutination test for the detection of mastitis due to Streptococcus agalactiae in cows.

    OpenAIRE

    Daniel, R C; Barnum, D A

    1986-01-01

    A commercial latex agglutination test for the detection of Group B streptococcal antigens was used to detect infection due to Streptococcus agalactiae in whey of bovine milk samples. Fifteen out of 17 known infections were detected, but it was necessary to incubate the wheys at 37 degrees C for 18 hours in nine of the samples. It was found that the latex agglutination test could detect Group streptococcal carbohydrate antigens in whey samples from artificially infected quarters from one to fo...

  6. Molluscicidal activity of crown of Christ (Euphorbia splendens var. hislopii) (Euphorbiaceae) latex submitted to pH variation

    OpenAIRE

    Vasconcellos Maurício Carvalho de; Santos José Augusto Albuquerque dos; Silva Ivonise Paz da; Lopes Fátima Eliana Ferreira; Schall Virgínia Torres

    2003-01-01

    Laboratory and field bioassays have confirmed the specificity of the molluscicidal activity of the Euphorbia splendens var. hislopii latex (crown of Christ) (Euphorbiaceae) over snails of the species Biomphalaria glabrata, B. tenagophila, B. straminea, B. pfeifferi and Bulinus sp. in the control of Schistosoma mansoni. In the present study, the effect of the pH variation on lethal concentration (LC90) over B. tenagophila was evaluated. Bioassays with the aqueous solutions of the latex ranging...

  7. Antioxidant and antiapoptotic activities of Calotropis procera latex on Catfish (Clarias gariepinus) exposed to toxic 4-nonylphenol.

    Science.gov (United States)

    Sayed, Alaa El-Din H; Mohamed, Nadia H; Ismail, Mady A; Abdel-Mageed, Wael M; Shoreit, Ahmed A M

    2016-06-01

    Calotropis procera L. is known as medicinal plant. The Phytochemical analyzes of its latex revealed that it possessed antioxidants, namely terpenes, phenolic compounds and cardenolides, flavonoids and saponins, while tannins, alkaloids and resin were absent in moderate to high concentration. In the present study, the role of latex of Calotropis procera as antioxidant and antiapoptotic was reported. To carry out this aim, fishes were exposed to 100 µg l(-1) 4-nonylphenol as chemical pollutant. The enzymes, superoxidase dismutase, catalase, acetlycholinstrase (AchE), glutathione s-transferase, cortisol, G6PDH) and apoptotic cells increased significantly (p<0.05) accompanied by irregular disturbance of (Na(+), K(+)) ions in the presence of 4-nonylphenol. On the other hand, these enzymes, ions, and apoptotic cells decreased normally and significantly (p<0.05) in the presence of latex. Total phenol content, total capacity antioxidant, reducing power decrease significantly (p<0.05) in the presence of 4-nonylphenol and increase normally in the presence of latex. Latex was used for the first time to protect catfish after 4-nonylphenol exposure. Our study confirms that crude latex of Calotropis procera possessed antioxidant and antiapoptotic activities against the toxicity of 4-Nonylphenol. PMID:26946283

  8. Numerical analysis of microstructure formation of magnetic particles and nonmagnetic particles in MR fluids

    International Nuclear Information System (INIS)

    Microstructure formation of magnetic particles and nonmagnetic particles in MR fluids is investigated using the particle method simulation. Nonmagnetic sphere particles are rearranged in the field direction due to the chain-like cluster formation of magnetic particles. In the contrast, the nonmagnetic spherocylinder particles are not sufficiently rearranged in the field direction by using the cluster formation of sphere magnetic particles.

  9. Extraction of high-quality genomic DNA from latex-containing plants.

    Science.gov (United States)

    Michiels, An; Van den Ende, Wim; Tucker, Mark; Van Riet, Liesbet; Van Laere, André

    2003-04-01

    The isolation of intact, high-molecular-mass genomic DNA is essential for many molecular biology applications including long PCR, endonuclease restriction digestion, Southern blot analysis, and genomic library construction. Many protocols are available for the extraction of DNA from plant material. However, for latex-containing Asteraceae (Cichorioideae) species, standard protocols and commercially available kits do not produce efficient yields of high-quality amplifiable DNA. A cetyltrimethylammonium bromide protocol has been optimized for isolation of genomic DNA from latex-containing plants. Key steps in the modified protocol are the use of etiolated leaf tissue for extraction and an overnight 25 degrees C isopropanol precipitation step. The purified DNA has excellent spectral qualities, is efficiently digested by restriction endonucleases, and is suitable for long-fragment PCR amplification. PMID:12672415

  10. Studying the allergicability of proteins in dried latex films vulcanized by radiation

    International Nuclear Information System (INIS)

    The nitrogen content in dried latex films after leaching in various media has been determined. The amount of protein in leached rubber films was evaluated in the 0.9% saline solution. Electrophoretic analysis of proteins from the saline extracts of dried latex films, which were vulcanized by gamma-rays of Co-60 at the 25 kGy absorption dose using n-butyl acrylate as a sensitizer, was also carried out. The pyrogenic tests on rabbit were examined. From the experimental results, it was concluded that the applications of RVNRL films are safe for end-users, and it was indicated that either surfactant or diluted alkaline solution was one of the best media to treat soluble proteins from rubber films due to their skin allergicabilities

  11. The sensitizing effect of acrylates on radiation vulcanization of natural rubber latex

    International Nuclear Information System (INIS)

    The sensitizing effect of acrylates on radiation vulcanization of natural rubber latex was studied. The results indicate that Gc value of crosslinking (Gc) will be higher at the same radiation dose when a sensitizer exists, and Gc value decreases with the increase of radiation dose (D) conforming to the formula Gc KD-α, where K and α are constants depending on sensitizers. The more sensitizers added, the greater the Gc value. However, the viscosity of the natural rubber latex also increases rapidly along with the increase of sensitizers added. Some sensitizers, such as TMPTA, can decrease the optimum dose from about 200 kGy to approximately 20 kGy according to our experiment. The tensile strength of the film can reach round 20 MPa. Other physical properties are comparable to those of unsensitized. (author)

  12. The design of an irradiator for the continuous processing of liquid latex

    Science.gov (United States)

    Reuter, O.; Langley, R.; Zn, Wan Manshol Bin W.

    1998-06-01

    This paper presents anew design concept for a gamma irradiation plant for the continuous processing of pumpable liquids. Typical applications of such a plant include ∗ the irradiation vulcanisation of natural latex rubber ∗ disinfection of municipal sewage sludge for agricultural use ∗ sterilisation of liquids in the pharmaceutical and cosmetics industries ∗ industrial processing of bulk liquids The authors describe the design and operation of the latex irradiator now operating on a small production scale in Malaysia and proposed developments. The design allows irradiation processing to be carried out under an inert or other gaseous environment. State-of-the-art computer control system ensures the fully automatic processing operation needed by industrial computers.

  13. Uniform lab-scale biocatalytic nanoporous latex coatings for reactive microorganisms.

    Science.gov (United States)

    Gosse, Jimmy L; Flickinger, Michael C

    2011-01-01

    This chapter describes a method for generating uniform lab-scale biocatalytic nanoporous latex coatings. Nearly everything we come into contact with on a daily basis has been coated with some polymer material. High-speed waterborne polymer coating and ink-jet printing techniques are mature technologies. Methods for immobilizing microorganisms in lab-scale waterborne latex biocatalytic coatings draw on existing coating technologies for generating precision industrial paint and paper coatings and would therefore be amenable to scale up in future applications. An inherent problem for many lab-scale techniques is coating uniformity. The method described here has been developed to dramatically increase the uniformity of multiple individual small surface area coatings derived from a single coating template by minimizing edge effects due to emulsion drying adjacent to the edge of the mask. PMID:21553194

  14. The role of proteins on the thermal oxidative aging of radiation vulcanized natural rubber latex

    International Nuclear Information System (INIS)

    The effect of Hevea latex proteins on the aging properties of radiation vulcanized natural rubber latex (RVNRL) was investigated. Unpurified RVNRL films exhibited better aging properties than the purified RVNRL films. A sharp decrease in tensile strength was observed after aging when RVNRL films were leached in 1% NH sub 4 OH. However, when these films were soaked in ethanol prior to leaching, the aging properties approximated those of the unleached samples. Kjeldahl and FT-IR analyses of the leached and unleached RVNRL films indicated a higher protein content for both the unleached and ethanol-soaked films than for leached films. Electrophoretic analysis of the proteins present in the NH, extracts of leached RVNRL films showed a high concentration of hevein. This protein was not found in the ATH, extracts of ethanol soaked films. Hevein was shown to improve the aging properties of RVNRL

  15. texreg: Conversion of Statistical Model Output in R to LATEX and HTML Tables

    Directory of Open Access Journals (Sweden)

    Philip Leifeld

    2013-11-01

    Full Text Available A recurrent task in applied statistics is the (mostly manual preparation of model output for inclusion in LATEX, Microsoft Word, or HTML documents usually with more than one model presented in a single table along with several goodness-of-fit statistics. However, statistical models in R have diverse object structures and summary methods, which makes this process cumbersome. This article first develops a set of guidelines for converting statistical model output to LATEX and HTML tables, then assesses to what extent existing packages meet these requirements, and finally presents the texreg package as a solution that meets all of the criteria set out in the beginning. After providing various usage examples, a blueprint for writing custom model extensions is proposed.

  16. Development of an efficient process for radiation vulcanization of natural rubber latex using hydroperoxide with sensitizers

    International Nuclear Information System (INIS)

    An attempt was made to reduce radiation dose for radiation vulcanization of natural rubber latex. One of the best methods found was to co-vulcanize the latex using partial radiation vulcanization at 4 kGy with 5 phr n-butyl acrylate as sensitizer and 0.1 phr t-butyl hydroperoxide (BHPO) as co-sensitizer followed by redox vulcanization using either 4 phr fructose at temperature of 60 degree C for 3 hours or 0.2 phr BHPO and 0.4 phr tetra-ethylene pentamine (TEPA) at room temperature for I hour. The rubber film obtained had tensile strength of about 25 MPa, modules 300% of 0. 9 MPa and cross link density of about 1. 5 x 10 sup 19 crosslink/cm sup 3. It was noted that the crosslink density of rubber films from the co-vulcanization was the average value of the values obtained by radiation vulcanization and redox vulcanization

  17. The effect of proteins on the aging properties of radiation vulcanized natural rubber latex

    International Nuclear Information System (INIS)

    The effect of natural rubber latex (NRL) proteins on the aging properties of NRL films was investigated. SDS-PAGE electrophoresis of the rubber proteins in NRL (Sri-Lanka) indicated a total of 18 proteins. A sharp decrease in tensile strength was observed after aging when NRL films were leached in 1% NH4OH. However, when these films were soaked in ethanol prior to leaching, the aging properties approximated those of the unleashed samples. Electrophoretic analysis of the proteins present in the NH3 extracts of leached RVNRL films showed a high concentration of the protein herein. This protein was not found in the NH3 extracts of ethanol soaked films. NRL proteins were shown to decelerate the aging process of Radiation Vulcanized Natural Rubber Latex (RVNRL) films. Among the proteins, herein exhibited good anti-aging properties. The hydrolyzates from NR proteins also enhanced considerably the aging properties of RVNRL. (auth.). 8 refs.; 40 figs.; 30 tabs

  18. Latex paint as a delivery vehicle for diethylphthalate and di-n-butylphthalate

    DEFF Research Database (Denmark)

    Schripp, Tobias; Salthammer, Tunga; Fauck, Christian;

    2014-01-01

    sizes (0.25 m3 and 55 m3), and, in the larger chamber, at two different temperatures (23 °C and 30 °C). The emitting material was latex wall paint that had been doped with two plasticizers, diethylphthalate (DEP) and di-n-butylphthalate (DnBP). The phthalate content in the paint was varied in the small...... gas-phase concentration at steady state(y). For both, DEP and DnBP, the y0 obtained was lower than the respective saturation vapor pressure (Ps). Furthermore, for both phthalates in latex paint, the material/air partition coefficient (C0/y0) was close in value to the octanol/air partition coefficient...

  19. Fine-tuning of process conditions to improve product uniformity of polystyrene particles used for wind tunnel velocimetry

    Science.gov (United States)

    Ray, Asit K.

    1990-01-01

    Monodisperse polymer particles (having uniform diameter) were used for the last two decades in physical, biological, and chemical sciences. In NASA Langley Research Center monodisperse polystyrene particles are used in wind tunnel laser velocimeters. These polystyrene (PS) particles in latex form were formulated at the Engineering Laboratory of FENGD using emulsion-free emulsion polymerization. Monodisperse PS latices particles having different particle diameters were formulated and useful experimental data involving effects of process conditions on particle size were accumulated. However, similar process conditions and chemical recipes for polymerization of styrene monomer have often yielded monodisperse particles having varying diameters. The purpose was to improve the PS latex product uniformity by fine-tuning the process parameters based on the knowledge of suspension and emulsion polymerization.

  20. Toxicological study of the molluscicidal latex of Euphorbia splendens: irritant action on skin and eye

    Directory of Open Access Journals (Sweden)

    J. C. B. R. Freitas

    1991-01-01

    Full Text Available Aqueous solutions of the molluscicidal latex of Euphorbia splendens are irritant to the rabbit eye in concentrations higher than 0.35% and to the rabbit skin in concentrations higher than 0.5%. Although this irritant potential does not proclude its use as a molluscicide, special precautions are recommended for hanbdling and application of the product and the hazard of skin tumor-promoting potencial should be carefully investigated before its use for schistosomiasis vector control.

  1. Toxicological study of the molluscicidal latex of Euphorbia splendens: irritant action on skin and eye

    OpenAIRE

    J. C. B. R. Freitas; O. A. F. Presgrave; F. F. Fingola; M. A. C. Menezes; M.C. Vasconcellos; V. T. Schall; Paumgartten, F. J. R.

    1991-01-01

    Aqueous solutions of the molluscicidal latex of Euphorbia splendens are irritant to the rabbit eye in concentrations higher than 0.35% and to the rabbit skin in concentrations higher than 0.5%. Although this irritant potential does not proclude its use as a molluscicide, special precautions are recommended for hanbdling and application of the product and the hazard of skin tumor-promoting potencial should be carefully investigated before its use for schistosomiasis vector control.

  2. Diagnostic value of latex agglutination test in diagnosis of acute bacterial meningitis

    OpenAIRE

    Syeda Fasiha Mohammadi; Patil, Asha B; Shobha D Nadagir; Namrata Nandihal; S A Lakshminarayana

    2013-01-01

    Objectives: To know the incidence of bacterial meningitis in children below five years of age. To compare conventional culture and antigen detection methods ( Latex agglutination test). Materials and Methods: 100 CSF samples of clinically suspected meningitis cases in children below 5 years of age were included. The samples were subjected to cell count, Gram stain, culture and LAT. The organisms isolated in the study were characterized according to standard procedures. Results: Of the 100 cas...

  3. Migration of BTEX and phthalates from natural rubber latex balloons obtained from the Sri Lankan market

    OpenAIRE

    Jayawardena, Imanda; Godakumbura, Pahan I.; Prashantha, M. A. B.

    2016-01-01

    The current study evaluates the migration of benzene, toluene, ethylbenzene, xylene (BTEX) and phthalates into artificial saliva from natural rubber latex (NRL) balloons available for sale in Sri Lanka. It was discovered that at least one BTEX compound migrated from almost all the brands. The migration of four phthalates; diethyl phthalate, dibutyl phthalate, di-isobutyl phthalate and butyl benzyl phthalate were also observed. Migratory levels of BTEX and phthalates in most of the balloon bra...

  4. Study on preparation of new antioxidants for radiation vulcanized natural rubber latex product. Antioxidant from keratin

    International Nuclear Information System (INIS)

    The thermo-oxidative aging resistance of radiation vulcanization of natural rubber latex (RVNRL) products should be adequately by using suitable antioxidants or new kind of effective antioxidant. This work presents the results of preparation of natural antioxidant from hair keratin. Characteristics and effectiveness of resultant antioxidant are also presented. The results obtained indicates that antioxidant made from hair keratin is safe and effective for rubber products from RVNRL. (author)

  5. SAXS and WAXS study of poly(butyl methacrylate) / montmorillonite nanocomposite latexes

    Czech Academy of Sciences Publication Activity Database

    Pleštil, Josef; Sedláková, Zdeňka; Baldrian, Josef; Holub, P.

    Belgrade : Institut of Technical Sciences of the Serbian Academy of Sciences & Arts, 2009 - (Uskokovic, D.). s. 154 [Annual Conference Yucomat 2009 /11./. 31.08.2009-04.09.2009, Herceg Novi] R&D Projects: GA AV ČR KAN100500651; GA MŠk ME09058 Institutional research plan: CEZ:AV0Z40500505 Keywords : hybrid nanocomposite * montmorrilonite * latex * SAXS * WAXS Subject RIV: CD - Macromolecular Chemistry

  6. Effect of opening girth and some latex physiological parameters on yield of Rubber (Hevea brasiliensis

    Directory of Open Access Journals (Sweden)

    H. K. L. K. Gunasekera

    2013-09-01

    Full Text Available Field experiment was conducted to investigate the possibility of exploiting rubber (Hevea brasiliensis for latex at a lower stem girth (40 and 45 cm and physiological yield parameters were monitored to establish factors responsible for differences in yield due to opening girths or tapping systems tested. Three different Hevea genotypes, i.e. RRISL 211, RRIC 121 and RRIC 102 were exploited at different growth stages, i.e. girth of 40 cm (G40, girth of 45 cm (G45 and girth of 50 cm (G50, using different tapping systems. Significant clonal differences were observed for the initial rate of latex flow (IFR, plugging index (PI, total volume of latex (vol, dry rubber content (DRC and dry rubber yield when tapping commenced at different opening girths. The overall results of the present study clearly showed that the plugging index was relatively high in trees opened at lower girths, i.e. 40 cm (G40 than in trees opened at higher girths, i.e. G45 and G50. Yield differences between trees of the same clone were mainly caused by differences in IFR, while differences between clones were mainly associated with differences in flow time. There is a highly significant positive correlation between PI and DRC irrespective of the tapping systems and opening girths. This study clearly showed that the DRC, PI and IFR vary according to year of tapping, tapping system and opening girth. At the immature phase (especially G40 trees during the first year were probably not mature enough to show normal latex flow relationships. Furthermore, variations in yield determining parameters have to be taken in to account in devising strategies for yield improvement in different clones.

  7. Local imipenem activity against Pseudomonas aeruginosa decreases in vivo in the presence of siliconized latex.

    Science.gov (United States)

    Pichardo, C; Conejo, M C; Docobo-Pérez, F; Velasco, C; López-Rojas, R; García, I; Pachón-Ibáñez, M E; Rodríguez, J M; Pachón, J; Pascual, A

    2011-02-01

    Zinc eluted from siliconized latex (SL) increases resistance of Pseudomonas aeruginosa to imipenem in vitro. A foreign body peritonitis model was used to evaluate the activity of imipenem using SL or silicone (S) implants. No differences were observed in mortality, positive blood cultures and tissue bacterial counts between SL and S implants. Implant-associated counts, however, were significantly higher in the SL group. It is concluded that SL decreases the activity of imipenem against P. aeruginosa. PMID:20936490

  8. The influence of temperature and reaction time in the degradation of natural rubber latex

    International Nuclear Information System (INIS)

    Liquid natural rubber (LNR /LENR) should be considered as a new material instead of a new type of rubber though they have the same configuration as the rubber used. In this work, thermal degradation of natural rubber latex was carried out to obtain LNR/LENR by varying the reaction time at different temperatures. The degraded polymers were characterized structurally using FTIR and NMR spectroscopies and the average molecular weights were determined by membrane-osmometry and viscometry. (author)

  9. Ocular toxicity by latex of Calotropis procera (Sodom apple)

    OpenAIRE

    Basak Samar; Bhaumik Arup; Mohanta Ayan; Singhal Prashant

    2009-01-01

    We report the spectrum of ocular toxicity following accidental inoculation of latex of Calotropis procera (Sodom apple) in 29 eyes between January 2003 and December 2006. All patients presented with sudden painless dimness of vision with photophobia. Twenty-five (86%) patients had initial visual acuity of less than 20/60. All eyes had conjunctival congestion and mild to severe corneal edema with Descemet′s folds. Three (10%) eyes had an epithelial defect, nine (31�...

  10. Trial Production of Surgical Gloves from Irradiated Natural Rubber Latex on Factory Scale

    OpenAIRE

    Utama, M.; Herwinarni; M. Sumarti; Siswanto; Suharyanto; S. Ruslim

    2005-01-01

    Trial production of surgical gloves from irradiated natural rubber latex at the PT. Laxindo Utama Serang Banten glove factory has been carried out. The variation of heating temperature and leaching time during processing were evaluated. The physical and mechanical properties and the protein allergen respond of surgical gloves using ELISA method were measured. The results showed that the physical and mechanical of surgical gloves such as tensile strength, modulus, and elongation at break arefo...

  11. Rubber Latex Gloves as a Direct Dosimeter for Measuring Dermal Harvester Pesticide Exposure Particularly With Malathion

    OpenAIRE

    Lopez, Terry Enriquez

    2011-01-01

    Hands are an important route of dermal exposure to agricultural pesticides during strawberry harvesting. Direct dosimeters that trap pesticide residues as they contact workers during harvesting may be valuable sources for estimates of exposure. Latex gloves as hand dosimeters have been evaluated in two settings: 1) commercial strawberry farms, and, 2) controlled studies using a surrogate contact transfer device and malathion-treated turf. With the assistance of field operators from a commerci...

  12. A New Cytotoxic 19-Nor-cardenolide from the Latex of Antiaris toxicaria

    Directory of Open Access Journals (Sweden)

    Wen-Li Mei

    2009-09-01

    Full Text Available A new nor-cardenolide, named toxicarioside H (1, was isolated from the latex of Antiaris toxicaria (Pers. Lesch (Moraceae. Its structure was elucidated on the basis of HRFAB-MS and spectroscopic techniques (IR, UV, 1D and 2D NMR. Compound 1 showed significant cytotoxicity against K562, SGC-7901, SMMC-7721, and HeLa cell lines in vitro by MTT method.

  13. Wear of conveyor chains with polymer rolls

    OpenAIRE

    Kerremans, Vincent; Rolly, Tom; DE BAETS, PATRICK; De Pauw, Jan; Sukumaran, Jacob; Perez Delgado, Yeczain

    2011-01-01

    Roller conveyor chains are common used to transport goods in production lines or assembly lines, such as pallets, cars or steel coils. They are sometimes used in severe environments, soiled with water, foreign particles, chemicals or other contaminants. Normal use will result in wear of the components of the chain which can lead to unexpected failure and costly production downtime. Today, few literature on the wear of conveyor chain is available and there are almost no reliable test-rigs to g...

  14. Decolorization of crude latex by activated charcoal, purification and physico-chemical characterization of religiosin, a milk-clotting serine protease from the latex of Ficus religiosa.

    Science.gov (United States)

    Kumari, Moni; Sharma, Anurag; Jagannadham, M V

    2010-07-14

    The crude latex of Ficus religiosa is decolorized by activated charcoal. Decolorization follows the Freundlich and Langmuir equations. A serine protease, named religiosin, has been purified to homogeneity from the decolorized latex using anion exchange chromatography. Religiosin is a glycoprotein with a molecular mass of 43.4 kDa by MALDI-TOF. Religiosin is an acidic protein with a pI value of 3.8 and acts optimally at pH 8.0-8.5 and temperature 50 degrees C. The proteolytic activity of religiosin is strongly inhibited by PMSF and chymostatin indicating that the enzyme is a serine protease. The extinction coefficient (epsilon(1%)(280)) of religiosin is 29.47 M(-1) cm(-1)with 16 tryptophan, 26 tyrosine, and 11 cysteine residues per molecule. The enzyme shows broad substrate specificity against natural as well as synthetic substrates with an apparent K(m) of 0.066 mM and 6.25 mM using casein and Leu-pNA, respectively. MS/MS analysis confirms the novelty of the enzyme. Religiosin is highly stable against denaturants, metal ions, and detergents as well as over a wide range of pH and temperature. In addition, the enzyme exhibits milk-clotting as well as detergent activity. PMID:20560603

  15. Theory of chain association versus liquid condensation

    NARCIS (Netherlands)

    Roij, R. van

    1996-01-01

    We combine the original van der Waals description for liquid condensation with the association theory of ideal particles into a simple association theory of nonideal chains. The theory shows that vapor-liquid coexistence becomes metastable if the tendency to form weakly interacting chains is suffici

  16. Safety Evaluation Test on Human for Radiation Pre vulcanised Natural Rubber Latex (RVNRL)

    International Nuclear Information System (INIS)

    This paper discussed about clinical test conducted to determine safety evaluations on human for latex examination gloves and latex films made from Radiation Vulcanized Natural Rubber Latex (RVNRL). Two types of test were being adopted which are i) Modified Draize-95 test and ii) Patch Test on Sensitized Individuals. Modified Draize-95 test was conducted on 200 non-sensitized human subjects and Patch Test on Sensitized Individuals was conducted on 25 individuals who are allergic to the defined major chemical sensitizer presents in natural rubber product. It was found that Modified Draize-95 test has prove that there is no clinical evidence on the presence of residual chemical additives at the level that may induce Type IV allergy in the un sensitized general user population in the RVNRL gloves. Meanwhile Patch Test on Sensitized Individuals has proved that the patch test conducted using the test article on 25 individuals who are allergic to the defined major chemical sensitizers present in natural rubber products, thiuram, carbamates or thiazoles produced a negative response, meeting the pre requirement for the claim of reduced reaction-inducing potential. (author)

  17. Rubber recovery from centrifuged natural rubber latex residue using sulfuric acid

    Directory of Open Access Journals (Sweden)

    Wirach Taweepreda

    2013-04-01

    Full Text Available Waste latex sludge from centrifuged residue, which is a null by-product of concentrated latex manufacturing, wasdigested to retrieve the rubber by using sulfuric acid. It was found that the acid concentration and digestion time have aneffect on the amount and purity of the retrieved rubber. Sulfuric acid at concentrations of more than 10% by weight with adigestion time of 48 hours completely digested waste latex sludge and gave rubber 10% by weight. The quality of the retrievedrubber was examined for Mooney viscosity (MV, plasticity retention index, nitrogen content, and ash content. The averagemolecular weight of the retrieved rubber, using gel permeation chromatography, was lower than that of normal natural rubber(NR which corresponds with the MV and initial plasticity (Po. The molecular structure from Fourier transform infraredspectroscopy (FT-IR indicated that the retrieved rubber surface is wet composed with hydroxyl functional ended group.The residue solution was evaporated and crystallized. The structure of crystals was determined using power X-ray diffractometer.

  18. Crystallization and preliminary X-ray diffraction studies of the glutaminyl cyclase from Carica papaya latex

    International Nuclear Information System (INIS)

    The glutaminyl cyclase isolated from C. papaya latex has been crystallized using the hanging-drop method. Diffraction data have been collected at ESRF beamline BM14 and processed to 1.7 Å resolution. In living systems, the intramolecular cyclization of N-terminal glutamine residues is accomplished by glutaminyl cyclase enzymes (EC 2.3.2.5). While in mammals these enzymes are involved in the synthesis of hormonal and neurotransmitter peptides, the physiological role played by the corresponding plant enzymes still remains to be unravelled. Papaya glutaminyl cyclase (PQC), a 33 kDa enzyme found in the latex of the tropical tree Carica papaya, displays an exceptional resistance to chemical and thermal denaturation as well as to proteolysis. In order to elucidate its enzymatic mechanism and to gain insights into the structural determinants underlying its remarkable stability, PQC was isolated from papaya latex, purified and crystallized by the hanging-drop vapour-diffusion method. The crystals belong to the orthorhombic space group P212121, with unit-cell parameters a = 62.82, b = 81.23, c = 108.17 Å and two molecules per asymmetric unit. Diffraction data have been collected at ESRF beamline BM14 and processed to a resolution of 1.7 Å

  19. Crystallization and preliminary X-ray diffraction studies of the glutaminyl cyclase from Carica papaya latex

    Energy Technology Data Exchange (ETDEWEB)

    Azarkan, Mohamed [Laboratoire de Chimie Générale I, Faculté de Médecine-ULB CP609, 808 Route de Lennik, B-1070 Brussels (Belgium); Clantin, Bernard; Bompard, Coralie [CNRS-UMR 8525, Institut de Biologie de Lille, BP 477, 1 Rue du Professeur Calmette, F-59021 Lille (France); Belrhali, Hassan [EMBL Grenoble Outstation, 6 Rue Jules Horowitz, BP 181, F-38042 Grenoble CEDEX 9 (France); Baeyens-Volant, Danielle [Laboratoire de Chimie Générale I, Faculté de Médecine-ULB CP609, 808 Route de Lennik, B-1070 Brussels (Belgium); Looze, Yvan [Laboratoire de Chimie Générale, Institut de Pharmacie-ULB CP206/04, Boulevard du Triomphe, B-1050 Brussels (Belgium); Villeret, Vincent, E-mail: vincent.villeret@ibl.fr [CNRS-UMR 8525, Institut de Biologie de Lille, BP 477, 1 Rue du Professeur Calmette, F-59021 Lille (France); Wintjens, René, E-mail: vincent.villeret@ibl.fr [Laboratoire de Chimie Générale, Institut de Pharmacie-ULB CP206/04, Boulevard du Triomphe, B-1050 Brussels (Belgium); Laboratoire de Chimie Générale I, Faculté de Médecine-ULB CP609, 808 Route de Lennik, B-1070 Brussels (Belgium)

    2005-01-01

    The glutaminyl cyclase isolated from C. papaya latex has been crystallized using the hanging-drop method. Diffraction data have been collected at ESRF beamline BM14 and processed to 1.7 Å resolution. In living systems, the intramolecular cyclization of N-terminal glutamine residues is accomplished by glutaminyl cyclase enzymes (EC 2.3.2.5). While in mammals these enzymes are involved in the synthesis of hormonal and neurotransmitter peptides, the physiological role played by the corresponding plant enzymes still remains to be unravelled. Papaya glutaminyl cyclase (PQC), a 33 kDa enzyme found in the latex of the tropical tree Carica papaya, displays an exceptional resistance to chemical and thermal denaturation as well as to proteolysis. In order to elucidate its enzymatic mechanism and to gain insights into the structural determinants underlying its remarkable stability, PQC was isolated from papaya latex, purified and crystallized by the hanging-drop vapour-diffusion method. The crystals belong to the orthorhombic space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 62.82, b = 81.23, c = 108.17 Å and two molecules per asymmetric unit. Diffraction data have been collected at ESRF beamline BM14 and processed to a resolution of 1.7 Å.

  20. Hierarchically structured self-supported latex films for flexible and semi-transparent electronics

    Science.gov (United States)

    Määttänen, Anni; Ihalainen, Petri; Törngren, Björn; Rosqvist, Emil; Pesonen, Markus; Peltonen, Jouko

    2016-02-01

    Different length scale alterations in topography, surface texture, and symmetry are known to evoke diverse cell behavior, including adhesion, orientation, motility, cytoskeletal condensation, and modulation of intracellular signaling pathways. In this work, self-supported latex films with well-defined isotropic/anisotropic surface features and hierarchical morphologies were fabricated by a peel-off process from different template surfaces. In addition, the latex films were used as substrates for evaporated ultrathin gold films with nominal thicknesses of 10 and 20 nm. Optical properties and topography of the samples were characterized using UV-vis spectroscopy and Atomic Force Microscopy (AFM) measurements, respectively. The latex films showed high-level transmittance of visible light, enabling the fabrication of semi-transparent gold electrodes. Electrochemical impedance spectroscopy (EIS) measurements were carried out for a number of days to investigate the long-term stability of the electrodes. The effect of 1-octadecanethiol (ODT) and HS(CH2)11OH (MuOH) thiolation and protein (human serum albumin, HSA) adsorption on the impedance and capacitance was studied. In addition, cyclic voltammetry (CV) measurements were carried out to determine active medicinal components, i.e., caffeic acid with interesting biological activities and poorly water-soluble anti-inflammatory drug, piroxicam. The results show that the fabrication procedure presented in this study enables the formation of platforms with hierarchical morphologies for multimodal (optical and electrical) real-time monitoring of length-scale-dependent biomaterial-surface interactions.