WorldWideScience

Sample records for prp-treated latex beads

  1. Magnetic Latex Beads Chaining on a Spherical Interface

    Science.gov (United States)

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

    2004-03-01

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

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

    Science.gov (United States)

    Coulombe, J N; Bronner-Fraser, M

    1984-11-01

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

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

    Science.gov (United States)

    Todd, Clifford S; Beyer, Douglas E

    2015-04-01

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

  4. The use of latex beads in external quality assurance and internal quality control for routine semen analysis.

    Science.gov (United States)

    Zuvela, Emily; Junk, Stephen; Moska, Natalie; Matson, Phillip

    2011-11-01

    The usefulness of latex beads of defined concentration was assessed as a substitute for sperm in the performance of External Quality Assurance (EQA) and Internal Quality Control (IQC) of semen analysis. Within the EQA programme, mean±SEM bias (%) was significantly reduced in 2007 compared to 2002 for both specialist (6.0%±5.4% vs. 55.0%±5.9%) and non-specialist (18.4%±5.9% vs. 90.9%±13.4%) laboratories (both p<0.0001), indicating improved accuracy over time. Within the IQC programme, the beads were used in the appraisal of two scientists, one experienced and one inexperienced, against a known standard. Beads were also used to calibrate eleven counting chambers, resulting in one old chamber being discarded due to its poor performance. The present study has shown that the use of a defined concentration of beads is an excellent adjunct to IQC and EQA programmes enabling the performance of both people and equipment to be assessed in an objective manner.

  5. Overcoming Angular Dependency When Teaching Light Scattering Using a Spectrofluorometer: The Molecular Weight of Latex Beads

    Science.gov (United States)

    Santos, Nuno C.; Fernandes, Miguel X. J. J.; Castanho, Miguel A. R. B.

    1999-09-01

    When using a spectrofluorometer in light-scattering experiments, it is impossible to perform angle-dependent studies. At first glance, this restriction seems to students to be an insurmountable obstacle. However, a spectrofluorometer offers some potentialities not available with classical laser light scattering spectroscopy, namely, the availability of broader wavelength ranges. Changing the wavelength changes the magnitude of the scattering vector. This has the same effect as a change in the measurement angle. Thus, it is possible to overcome angle dependency by accounting for wavelength dependency. This "shift" in dependencies is easily accessed by students because it results directly from the usual formalisms used in light scattering. Moreover, the students are encouraged, in practice, to elaborate innovative solutions, even from classical formalisms. This methodology is applied to the calculation of a series of molecular weights of polystyrene latex spheres. This system has several advantages: (i) water miscibility, (ii) definite shape, (iii) monodispersity (both size and shape), (iv) low cost, and (v) availability of latex spheres in a wide variety of sizes and composition. Although very well characterized with respect to size and shape (mainly by dynamic light scattering and electronic microscopy), latex spheres have been poorly studied in terms of molecular weight. Consequently, working in an innovative area of research proves stimulating for the students.

  6. Electrochemical nitrite nanosensor developed with amine- and sulphate-functionalised polystyrene latex beads self-assembled on polyaniline

    Energy Technology Data Exchange (ETDEWEB)

    Muchindu, Munkombwe; Waryo, Tesfaye; Arotiba, Omotayo [SensorLab, Department of Chemistry, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa); Kazimierska, Ewa; Morrin, Aoife; Killard, Anthony J.; Smyth, Malcolm R. [School of Chemical Sciences, Dublin City University, Dublin 9 (Ireland); Jahed, Nazeem; Kgarebe, Boitumelo; Baker, Priscilla G.L. [SensorLab, Department of Chemistry, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa); Iwuoha, Emmanuel I., E-mail: eiwuoha@uwc.ac.z [SensorLab, Department of Chemistry, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa)

    2010-05-30

    Aniline doped with polyvinyl sulphonate (PV-SO{sub 3}{sup -}) was electropolymerised on screen printed carbon (SPCE) and glassy carbon (GCE) electrodes. Then nano-structured polystyrene (PS{sub NP}) latex beads functionalised with amine (PS{sub NP}-NH{sub 2}) and sulphate (PS{sub NP}-OSO{sub 3}{sup -}) were self-assembled on the modified SPCE and GCE. The resultant polyaniline nanocomposites (PANI|PS{sub NP}-NH{sub 2} or PANI|PS{sub NP}-OSO{sub 3}{sup -}) were characterised by cyclic voltammetry (CV), UV-vis spectroscopy and scanning electron microscopy (SEM). Brown-Anson analysis of the multi-scan rate CV responses of the various PANI films gave surface concentrations of the order of 10{sup -8} mol cm{sup -2}. UV-vis spectra of the PANI films dissolved in dimethyl sulphoxide showed typical strong absorbance maxima at 480 and 740 nm associated with benzenoid pi-pi* transition and quinoid excitons of polyaniline, respectively. The SEM images of the PANI nanocomposite films showed cauliflower-like structures that are <100 nm in diameter. When applied as electrochemical nitrite sensor, sensitivity values of 60, 40 and 30 muA/mM were obtained for electrode systems containing PANI|PS{sub NP}-NH{sub 2}, PANI and PANI|PS{sub NP}-SO{sub 3}{sup -}, respectively. The corresponding limits of detection of the sensors were 7.4, 9.2 and 38.2 muM NO{sub 2}{sup -}.

  7. Latex bead-based artificial antigen-presenting cells induce tumor-specific CTL responses in the native T-cell repertoires and inhibit tumor growth.

    Science.gov (United States)

    Shen, Chuanlai; Cheng, Kai; Miao, Shenwei; Wang, Wei; He, Yong; Meng, Fanyan; Zhang, Jianqiong

    2013-02-01

    Cell-free artificial antigen-presenting cells (aAPCs) were generated by coupling H-2K(b)/TRP2 tetramers together with anti-CD28 and anti-4-1BB antibodies onto cell-sized latex beads and injected intravenously and subcutaneously into naïve mice and antigen-primed mice (B6, H-2K(b)). Vigorous tumor antigen-specific CTL responses in the native T-cell repertoire in each mouse model were elicited as evaluated by measuring surface CD69 and CD25, intracellular IFN-γ, tetramer staining and cytolysis of melanoma cells. Furthermore, the aAPCs efficiently inhibited subcutaneous tumor growth and markedly delayed tumor progression in tumor-bearing mice. These data suggest that bead-based aAPCs represent a potential strategy for the active immunotherapy of cancers or persistent infections. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Role of intestinal mucus on the uptake of latex beads by Peyer's patches and on their transport to mesenteric lymph nodes in rats.

    Science.gov (United States)

    Khan, J; Iiboshi, Y; Cui, L; Wasa, M; Okada, A

    1999-01-01

    The effects of N-acetylcysteine (NAC) as a mucolytic agent on the uptake of fluorescent polystyrene microparticles by Peyer's patches, on intestinal permeability, and on subsequent transport to mesenteric lymph nodes (MLNs) were investigated to establish the role of mucus gel layer in this process. Twenty rats were divided into two groups: control (n = 10) and NAC (n = 10). Fluorescent polystyrene latex beads of 3.2+/-0.2 microm in diameter were used as a probe for measuring the previously mentioned parameters. The solution of latex beads (0.1 mL) was injected into a 2-cm length of ileal loop containing Peyer's patches, with 0.1 mL of saline (control group) or with 0.1 mL of NAC solution (NAC group) within 10 cm proximal from the ileocaecal valve. Intestinal loops, portal blood, and neighboring MLNs were taken within 1 hour of injection. Intestinal sections were stained by periodic acid-Schiff reagent. Peyer's patches and MLNs were analyzed for the count of particles by image analysis using a confocal laser scanning microscope. Morphologically, periodic acid-Schiff positive uniform mucus gel was present in front of Peyer's patches of the control group, and mucus gel layer was disrupted and noncontinuous in the NAC group. The number of particles within Peyer's patches and MLNs in the NAC group was significantly higher than that in the control group (pNAC group was significantly higher than that in the control group (pmucus gel layer located in front of Peyer's patches is one of the important factors for the uptake of noxious macromolecules, and this in turn plays a major role on small intestinal permeability and subsequent translocation to MLNs.

  9. Rapid latex agglutination test for the serodiagnosis of human brucellosis

    NARCIS (Netherlands)

    Abdoel, Theresia H.; Smits, Henk L.

    2007-01-01

    We developed and evaluated a user-friendly latex agglutination assay for the serodiagnosis of human brucellosis. The assay was obtained by coating colored latex beads with Brucella lipopolysaccharides and drying of the activated beads onto white agglutination cards. Individual cards were sealed in a

  10. 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

  11. Simple latex agglutination assay for rapid serodiagnosis of human leptospirosis

    NARCIS (Netherlands)

    Smits, H. L.; van der Hoorn, M. A.; Goris, M. G.; Gussenhoven, G. C.; Yersin, C.; Sasaki, D. M.; Terpstra, W. J.; Hartskeerl, R. A.

    2000-01-01

    A newly developed latex agglutination assay for the detection of genus-specific Leptospira antibodies in human sera was evaluated. The assay is performed by mixing, on an agglutination card, serum with equal volumes of stabilized antigen-coated, dyed test and control latex beads and is read within 2

  12. Managing latex allergies at home

    Science.gov (United States)

    Latex products; Latex allergy; Latex sensitivity; Contact dermatitis - latex allergy ... Items that may contain latex include: Balloons Condoms and diaphragms Rubber bands Shoe soles Bandages Latex gloves Toys Paint Carpet backing Baby-bottle nipples and ...

  13. Latex agglutination test

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003334.htm Latex agglutination test To use the sharing features on this page, please enable JavaScript. The latex agglutination test is a laboratory method to check ...

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

    National Research Council Canada - National Science Library

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

    2017-01-01

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

  15. Latex Allergy: Tips to Remember

    Science.gov (United States)

    ... Treatments ▸ Library ▸ Allergy Library ▸ Latex allergy TTR Share | Latex Allergy This article has been reviewed by Thanai Pongdee, MD, FAAAAI Natural rubber latex, a milky fluid found in rubber trees, is ...

  16. Latex Allergy: A Prevention Guide

    Science.gov (United States)

    ... Health Topics Publications and Products Programs Contact NIOSH Latex Allergy A Prevention Guide Recommend on Facebook Tweet ... years--especially among health care workers. What is latex? In this pamphlet, the term "latex" refers to ...

  17. [Allergy to latex].

    Science.gov (United States)

    Laxenaire, M C; Moneret-Vautrin, D A

    In France 18% of all preoperative allergic shock syndromes result from allergic reactions to latex. IgE antibodies mediate the immediate hypersensitivity reaction to natural latex proteins extracted for the rubber tree (Hevea brasiliensis). Sensibilization occurs after repeated direct contact of the skin or mucosa with latex products including gloves, urinary catheters or after chronic inhalation of airborne particles of latex in the operating theatre. Clinical expressions include skin rash, asthma or anaphylactic shock. During the preoperative period, the shock may occur late after induction of anaesthesia and after the operative procedure has begun or after the arm cuff has been released. In obstetrics oxytocin injection can precipitate the phenomenon. Subjects at risk have been clearly identified: subjects who wear gloves regularly, those working in an environment contaminated with airborne latex, children who have undergone multiple operations on malformations of the urinary tract or who have had repeated catheterisms (40% of the spina bifida patients are sensitized), atopic subjects, those allergic to exotic fruits (banana, avocado, kiwi). These patients should be identified during the preoperative work-up in order to perform allergy tests. The diagnosis of over-sensitivity should be confirmed by prick-tests and perhaps complete antilatex antibody assay and challenge. All material composed of natural latex should be avoided for these patients. Proposed alternatives include synthetic rubber. Hypoallergenic gloves add no further safety. The operative procedure should be conducted using standard techniques.

  18. Blends of guayule natural rubber latex with commercial latex polymers

    Science.gov (United States)

    Guayule (Parthenium argentatum) is a woody desert shrub that produces natural rubber, cis-1,4 polyisoprene, by biosynthesis. It is currently cultivated in the southwestern United States as a source of latex and rubber for commercial development. Guayule latex is similar to Hevea latex in polymer mo...

  19. 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

  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 allergy in health care

    Directory of Open Access Journals (Sweden)

    Tina Virtič

    2012-11-01

    Full Text Available The increasing use of natural rubber latex medical gloves in the last three decades has caused an increase in latex allergy. The majority of risk groups for allergy development include health care workers, workers in the rubber industry, atopic individuals and children with congenital malformations. Three types of pathological reactions can occur in people using latex medical gloves: irritant contact dermatitis, allergic contact dermatitis and immediate hypersensitivity. The latex allergy is caused by constituent components of latex gloves and added powders; there are also numerous latex allergens involved in cross-reactivity between latex and fruits and vegetables, the so-called latex-fruit syndrome. The diagnosis is based on an accurate history of exposure, clinical presentation and confirmatory in vivo and in vitro tests. Prevention is the easiest, most effective and least expensive way to avoid latex allergy. Powder-free latex gloves with reduced levels of proteins and chemicals, and synthetic gloves for allergic workers must be provided in the work environment. There are already many health care institutions around the world where all latex products have been replaced by synthetic material products.

  2. Yeasts in Hevea brasiliensis Latex.

    Science.gov (United States)

    Glushakova, A M; Kachalkin, A V; Maksimova, I A; Chernov, I Yu

    2016-07-01

    Yeast abundance and species diversity in the latex of caoutchouc tree Hevea brasiliensis (Willd. ex Juss.) M611. Arg., on its green leaves, and in soil below the plant Was studied. The yeasts present in the fresh latex in concentrations of up to 5.5 log(CFU/g) were almost exclusively represented by the species Candida heveicola, which was previously isolated from Hevea latex in China. In the course of natural modification of the latex yeast diversity increased, while yeast abundance decreased. The yeasts of thickened and solidified latex were represented by typical epiphytic and ubiquitous species: Kodamea ohmeri, Debaryomyces hansenii, Rhodotorula mucilaginosa, and synanthropic species Candida parapsilosis and Cutaneotrichosporon arbori- formis. The role of yeasts in latex modification at the initial stages of succession and their probable role in de- velopment of antifungal activity in the latex are discussed.

  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...

  4. Latex allergy in the workplace.

    Science.gov (United States)

    Toraason, M; Sussman, G; Biagini, R; Meade, J; Beezhold, D; Germolec, D

    2000-11-01

    While less than 1% of the general population is sensitized to latex, the U.S. Occupational Safety and Health Administration estimates that 8-12% of health-care workers are sensitized. The major source of workplace exposure is powdered natural rubber latex (NRL) gloves. NRL is harvested from HEVEA: brasiliensis trees and ammoniated to prevent coagulation resulting in the hydrolysis of the latex proteins. Prior to use in manufacturing, the latex is formulated by the addition of multiple chemicals. Thus, human exposure is to a mixture of residual chemicals and hydrolyzed latex peptides. Clinical manifestations include irritant contact dermatitis, allergic contact dermatitis (type IV), and type I immediate hypersensitivity response. Type I (IgE-mediated) NRL allergy includes contact urticaria, systemic urticaria, angioedema, rhinitis, conjunctivitis, bronchospasm, and anaphylaxis. Taking an accurate history, including questions on atopic status, food allergy, and possible reactions to latex devices makes diagnosis of type-I latex allergy possible. To confirm a diagnosis, either in vivo skin prick testing (SPT) or in vitro assays for latex-specific IgE are performed. While the SPT is regarded as a primary confirmatory test for IgE-mediated disease, the absence of a U.S. Food and Drug Administration-licensed HEVEA: brasiliensis latex extract has restricted its use in diagnosis. Serological tests have, therefore, become critically important as alternative diagnostic tests. Three manufacturers currently have FDA clearance for in vitro tests, to detect NRL-specific IgE. The commercially available assays may disagree on the antibody status of an individual serum, which may be due to the assay's detecting anti-NRL IgEs to different allergenic NRL proteins. Sensitized individuals produce specific IgE antibody to at least 10 potent HEVEA: allergens, Hev b 1-Hev b 10, each of which differs in its structure, size, and net charge. The relative content and ratios of Hevs in the

  5. Determinación de la producción de Öxido Nítrico en Macrófagos Activados J774.1 como respuesta al tamaño de la carga fagocítica de partículas de látex y Leishmania amazonensis Determination of Nitric Oxide Production in Activate Macrophages J774.1 as effect of Phagocitic Load Volume of Latex Beads and Leishmania amazonensis

    Directory of Open Access Journals (Sweden)

    Camargo Jiménez Maria Helena

    2000-06-01

    this work, cultured macrophageswere exposed to latex beads at diferents proportions, to simulate phagocitic loads andphagosome volumes resembling those of the infection. Nitrite concentration and morphologicalparameters were measured at 48 hours post phagocytosis and infection with 24 hours ofactivation induced by IFN-γand LPS. Our results determined that macrophages with similarvolume of phagosomes generated by latex beads or L. amazonensisamastigotes have the samedecrease in inducible NO production. This suggest that this partial inhibition does not depenton the nature of phagocited particle. Phagosome volume increase correlates with the decreasein inducible NO production. Therefore, phagosome expansion may be one of the mechanismimplicated in the disminution of inducible NO production. The results support the evidencethat Leishmaniareduces inducible NO production, but contradicts the common interpretationthat this fenomena is specific of infection.

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

    Science.gov (United States)

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

    2014-01-01

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

  7. [Latex allergy--Part I].

    Science.gov (United States)

    Chełmińska, Marta

    2004-01-01

    Natural rubber latex (NRL), is a resin sap produced in the cells of caoutchouc plants. It is a water dispersion of cis-1,4-polisopren (caoutchouc)--35%, stabilized with little amounts of proteins, sugar, alcohol, fatty acids and salts. The concentration of all solid substances is about 40%, the rest is water. Immunogenicity of latex depends on the proteins it contains. For many years we read in medical papers about the cases of contact urticaria, asthma, rhinitis, and anaphylaxis after contacting with latex products. It turns out that medical staff is the group of high occupational risk, because of exposure to gloves and other latex products. It is connected with the fact of high gloves usage caused by the danger of virus infections: HIV, HBV, HCV. Latex allergy is one of the reasons of dramatic complications after surgical operations. People who are allergic to latex may have cross reactions to allergens not connected with occupational environment. These are: food and houseplants (Ficus benjamina). The frequency of latex allergy is about 0.1% of the population. In the groups of high risk the frequency rises sharply. It is 17% among medical staff and it reaches 60% among children with spina bifida.

  8. A Magnetic Bead Actuator

    NARCIS (Netherlands)

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

    2006-01-01

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

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

    African Journals Online (AJOL)

    alginate beads (without algae). The bioreactor containing algal beads (4 mm diameter) with 1.5 x 106 cells bead-1 (cell stocking) at concentration of 10.66 beads ml-1 wastewater (1:3 bead: wastewater, v/v) achieved complete removal of NH4 +-N nd about 95% reduction in phosphate removal within the experimental period ...

  10. 40 CFR 428.100 - Applicability; description of the latex-dipped, latex-extruded, and latex-molded rubber subcategory.

    Science.gov (United States)

    2010-07-01

    ... latex-dipped, latex-extruded, and latex-molded rubber subcategory. 428.100 Section 428.100 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS RUBBER MANUFACTURING POINT SOURCE CATEGORY Latex-Dipped, Latex-Extruded, and Latex-Molded Rubber Subcategory § 428.100...

  11. 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 filaggrin mutation...

  12. Cream concentrated latex for foam rubber products

    Science.gov (United States)

    Suksup, R.; Imkaew, C.; Smitthipong, W.

    2017-12-01

    Fresh natural latex (around 40% rubber and 60% water) can be transformed to concentrated natural latex (around 60% rubber and 40% water) in order to realise economical transportation and easier latex product’s preparation. The concentrated natural latex is an extremely valuable material. It can be applied for many types of products, for example, foam rubber as pillow and mattress, elastic band, etc. Industrially, the concentrated natural latex can be prepared by centrifugation which requires an enormous expensive machine. From the eco-friendly products point of view, most of rubber entrepreneurs in the world try to develop a green rubber product. So, the main objective of this study is to prepare the cream concentrated latex without any sophisticated machine. Thus, we work on a simple, cheap and green method that does not use any expensive machine but uses water-based chemical as sodium alginate to prepare the cream concentrated latex. The optimal amount of sodium alginate in the latex was studied. The main characteristics of the cream concentrated latex were tested by various technics, such as alkalinity, total solid content (TSC), dry rubber content (DRC), etc. We found that there are no significant differences of results between fresh natural latex and cream concentrated latex, except for the TSC and DRC. The TSC and DRC of cream latex are higher than those of fresh natural latex. Finally, we propose a model of natural rubber particle and sodium alginate to form the cream concentrated latex.

  13. The latex story.

    Science.gov (United States)

    Raulf, Monika

    2014-01-01

    The milky sap of the rubber tree Hevea brasiliensis is the source of the commercial production of natural rubber latex (NRL) devices, and also represents a source of potent allergenic proteins. NRL materials were introduced in the health care field in about 1840 with the advent of technical abilities to produce suitable and flexible NRL materials for medical products, especially gloves. In the late 1980s, with the increase of transmittable diseases, particularly HIV infection, the use of NRL gloves increased dramatically. During the 1990s, NRL emerged as a major cause of clinically relevant allergy in health care workers using NRL gloves and spina bifida patients with operation on the first day. The increased recognition of NRL allergies, the enhanced research on allergen characterization and sensitization mechanisms, and education about this allergy in health care facilities combined with the introduction of powder-free gloves with reduced protein levels are all factors associated with a decline in the number of suspected cases of NRL allergies in the late 1990s. NRL allergy is a very good example of a 'new allergy' that suddenly arises with tremendous health and economic implications, and also of an allergy which becomes history in a relatively short period of time based on successful primary prevention strategies by strict allergen avoidance. © 2014 S. Karger AG, Basel.

  14. EVALUATION OF LOW-VOC LATEX PAINTS

    Science.gov (United States)

    The paper gives results of an evaluation of four commercially available low-VOC (volatile organic compound) latex paints as substitutes for conventional latex paints by assessing both their emission characteristics and their performance as coatings. Bulk analysis indicated that ...

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

    African Journals Online (AJOL)

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

  16. Parametric characterizations in superparamagnetic latex

    Indian Academy of Sciences (India)

    The effect of synthesis parameters on the production of superparamagnetic latex, which are magnetite nanoparticles covered with a poly(methyl methacrylate) layer, ... Chemistry Department, Science and Literature Faculty, Balikesir University, 10145 Balikesir, Turkey; Physics Department, Science and Literature Faculty, ...

  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. Development of a blocking latex agglutination test for the detection of antibodies to chicken anemia virus.

    Science.gov (United States)

    Trinh, Dai Quang; Ogawa, Haruko; Bui, Vuong Nghia; Nguyen, Tham Thi Hong; Gronsang, Dulyatad; Baatartsogt, Tugsbaatar; Kizito, Mugimba Kahoza; AboElkhair, Mohammed; Yamaguchi, Shigeo; Nguyen, Viet Khong; Imai, Kunitoshi

    2015-09-01

    A blocking latex agglutination test (b-LAT) developed in this study was evaluated for the detection of antibodies against chicken anemia virus (CAV) in chickens. Polystyrene latex beads were coupled with a neutralizing monoclonal antibody (mAb) to CAV (mAb-beads). When mAb-beads were mixed with antigens prepared from the lysate of MDCC-MSB1 cells infected with CAV, agglutination occurred. A short pre-incubation of CAV antigens with CAV-specific antiserum inhibited the agglutination of mAb-beads. The test results were obtained within 5min. The specificity of b-LAT was evaluated using sera from specific pathogen-free chickens and sera containing antibodies to avian influenza virus, Newcastle disease virus, infectious bursal disease virus, and Marek's disease virus; nonspecific agglutination and cross-reactivity with antibodies to unrelated viruses were not observed. The examination of 94 serum samples collected from commercial breeder chickens of various ages (17-63 weeks) revealed good agreement (93.6%, Kappa value=0.82) between b-LAT and a virus neutralization test, known to be most sensitive and specific in the detection of antibodies to CAV. These results indicate that b-LAT, a simple and rapid test, is a useful and reliable tool in CAV serology. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Integration of latex protein sequence data provides comprehensive functional overview of latex proteins.

    Science.gov (United States)

    Cho, Won Kyong; Jo, Yeonhwa; Chu, Hyosub; Park, Sang-Ho; Kim, Kook-Hyung

    2014-03-01

    The laticiferous system is one of the most important conduit systems in higher plants, which produces a milky-like sap known as latex. Latex contains diverse secondary metabolites with various ecological functions. To obtain a comprehensive overview of the latex proteome, we integrated available latex proteins sequences and constructed a comprehensive dataset composed of 1,208 non-redundant latex proteins from 20 various latex-bearing plants. The results of functional analyses revealed that latex proteins are involved in various biological processes, including transcription, translation, protein degradation and the plant response to environmental stimuli. The results of the comparative analysis showed that the functions of the latex proteins are similar to those of phloem, suggesting the functional conservation of plant vascular proteins. The presence of latex proteins in mitochondria and plastids suggests the production of diverse secondary metabolites. Furthermore, using a BLAST search, we identified 854 homologous latex proteins in eight plant species, including three latex-bearing plants, such as papaya, caster bean and cassava, suggesting that latex proteins were newly evolved in vascular plants. Taken together, this study is the largest and most comprehensive in silico analysis of the latex proteome. The results obtained here provide useful resources and information for characterizing the evolution of the latex proteome.

  20. bEADS

    DEFF Research Database (Denmark)

    Williams, Peter Leslie; Overholt, Daniel

    2017-01-01

    While there are a great variety of digital musical interfaces available to the working musician, few offer the level of immediate, nuanced and instinctive interaction that one finds in an acoustic shaker. bEADS is a prototype of a digital musical instrument that utilises the gestural vocabulary...

  1. IDENTIFICATION OF ENCODED BEADS

    DEFF Research Database (Denmark)

    2005-01-01

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

  2. Relevance of latex aeroallergen for healthcare workers

    Directory of Open Access Journals (Sweden)

    X. Baur

    1996-01-01

    Full Text Available The dispersion of latex allergen bound on glove powder has been shown to be of clinical importance to latex-sensitized medical staff and patients. To investigate whether latex aeroallergen is associated with the development of latex allergic reactions in health care workers, air samples were collected in 33 hospital rooms and two physicians' offices. Concentrations of latex allergens in the samples were determined by a competitive inhibition immunoassay and related to reported hypersensitivity reactions and to specific IgE results of 111 staff members engaged in these rooms. Latex aeroallergen (up to 205 ng/m3 could be detected in all rooms where powdered latex gloves were used and ventilation systems were not installed. Conjunctivitis (n=10, rhinitis (n=12 and dyspnea (n=4 were reported exclusively by employees working in such contaminated rooms. Also workers with latex-specific IgE antibodies (n=l 7 were found only in these rooms. Urticaria in personnel (n=26 was reported in rooms with and without detectable allergen load. All symptoms were significantly associated with latex-specific IgE antibodies. Our results demonstrate that immediate-type sensitization and allergic symptoms are associated with detectable latex aeroallergen.

  3. Glass bead cultivation of fungi

    DEFF Research Database (Denmark)

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

    2013-01-01

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

  4. Coated Aerogel Beads

    Science.gov (United States)

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

    2014-01-01

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

  5. [Latex allergy. Diagnosis and therapeutic aspects].

    Science.gov (United States)

    Sánchez Palacios, A

    2001-01-01

    In the last two decades of the 20th century, latex allergy has reached epidemic proportions. Epidemiological studies demonstrate that 3-25 % of health personnel is allergic to latex. The main risk groups are health workers, machine operators in latex factories, and children with spina bifida and urogenital anomalies. From the allergenic point of view, latex contains 240 peptides but approximately 50 are able to react to IgE. Latex elongation factor Hevdl is the relevant allergen in patients with spina bifida. Prohevein (hev B6) behaves as a major allergen, since it reacts to IgE in most of the sera of patients with latex allergy. The nature of latex is complex; it is an allergenic mixture that depends on chemical, immunological and epidemiological variables. Latex proteins show strong cross reactivity with several proteins from fruit and vegetable grains such as avocado, potato, banana, tomato, chestnut, and kiwi. In vivo studies have shown that class I chitinase from avocado and chestnut behave as major allergens in allergic patients with latex-fruit syndrome. The clinical manifestations related to the use of latex products depend on the type of exposure, the amount of the allergen, and individual variability. The most useful diagnostic method is the skin prick test. Several perioperative guidelines are recommended in patients sensitized to latex as well as various alternatives to rubber gloves. An increasing number of studies describe the efficacy of etiological treatment (immunotherapy), using different guidelines and routes of administration. These preliminary data encourage the hope that in the near future immunomodulatory therapy will be available to mitigate against the latex allergy epidemic.

  6. ORIGINAL ARTICLES Allergenicity of latex rubber products used in ...

    African Journals Online (AJOL)

    , to minimise the risk of sensitisation to these proteins. Background. Allergens from latex products in health care settings are known to trigger latex-induced allergic reactions in HCWs. Adverse effects associated with the use of latex rubber ...

  7. 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.

  8. 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.

  9. Ficus sycomorus latex: A thermostable peroxidase

    African Journals Online (AJOL)

    ajl yemi

    2011-11-30

    Nov 30, 2011 ... cannabinoids and tannins (Evert, 2006). Latex not only serves as a repository for natural products but also exhibit unique proteomes, including ..... characias latex contained 1 mol of endogenous calcium per mol of enzyme; removal of this calcium ion resulted in almost complete loss of the enzyme activity.

  10. RADIATION INDUCED VULCANIZATION OF RUBBER LATEX

    Science.gov (United States)

    Mesrobian, R.B.; Ballantine, D.S.; Metz, D.J.

    1964-04-28

    A method of vulcanizing rubber latex by exposing a mixture containing rubber latex and from about 15 to about 21.3 wt% of 2,5-dichlorostyrene to about 1.1 megarads of gamma radiation while maintaining the temperature of the mixture at a temperature ranging between from about 56 to about 59 deg C is described. (AEC)

  11. Relationships between physiological parameters of latex and ...

    African Journals Online (AJOL)

    Natural rubber must be technically specified for various uses. Variability in technological properties of raw nat-ural rubber leads to problems of grading. A study was conducted to establish relationships between physio-logical parameters of latex and technological properties of the raw rubber. The latex samples were ...

  12. Writing with LateX

    OpenAIRE

    Pokutta, Sebastian

    2003-01-01

    Almost all publications in mathematics and other natural sciences are originally created using LaTeX. This format has many advantages, especially concerning the retrieval of information. Moreover, given a LaTeX-document, it is possible to generate almost every customary format, for instance, one can easily obtain the corresponding dvi-, ps-, or pdf-file. In contrast to its importance, however, the LaTeX-format has been widely neglected in many library projects. The question concerning us in ...

  13. Jackfruit anaphylaxis in a latex allergic patient.

    Science.gov (United States)

    Wongrakpanich, Supakanya; Klaewsongkram, Jettanong; Chantaphakul, Hiroshi; Ruxrungtham, Kiat

    2015-03-01

    Several fruits have been reported to crossreact with latex antigen in latex allergy patients but little is known regarding tropical fruits in particular. Here we report the case of a 34-year old nurse who developed anaphylaxis following the ingestion of dried jackfruit (Artocarpus heterophyllus). The patient had a history of chronic eczema on both hands resulting from a regular wear of latex gloves. She and her family also had a history of atopy (allergic rhinitis and/or atopic dermatitis). The results of skin prick tests were positive for jackfruit, latex glove, kiwi and papaya, but the test was negative for banana. While we are reporting the first case of jackfruit anaphylaxis, further research needs to be conducted to identify the mechanisms underlying it. In particular, in-vitro studies need to be designed to understand if the anaphylaxis we describe is due to a cross reactivity between latex and jackfruit or a coincidence of allergy to these 2 antigens.

  14. Transcript Profiling of Hevea brasiliensis during Latex Flow

    Science.gov (United States)

    Chao, Jinquan; Yang, Shuguang; Chen, Yueyi; Tian, Wei-Min

    2017-01-01

    Latex exploitation enhances latex regeneration in rubber trees. The latex exploitation-caused latex flow lasts from 10 min to a few hours, which is convenient for exploring the transcript profiling of latex metabolism-related genes at the different stages of latex flow. In the present study, the expression pattern of 62 latex metabolism-related genes involved in water transportation, carbohydrate metabolism, natural rubber biosynthesis, hormone signaling, ROS generation and scavenging, and latex coagulum across three stages of latex flow between rubber tree clones CATAS7-33-97 and CATAS8-79 were comparatively analyzed by quantitative real-time PCR. The two clones show differences in latex regeneration and have a different duration of latex flow. The results showed that the expression levels of 38 genes were significantly higher in CATAS8-79 latex than in CATAS7-33-97 during latex regeneration, while 45 genes had a notably higher expression level in CATAS8-79 latex during latex flow. Together with the activation of the MEP pathway and jasmonate pathway in CATAS8-79 latex, HbPIP1;3, HbPIP1;4, HbSUT3, HbSus3, HbHMGS1-2, HbMK should contribute to the high latex regeneration ability. The up-regulation of ethylene signaling and Hb44KD and the down-regulation of latex coagulation-related genes in CATAS8-79 latex might contribute to its longer latex flow duration. This study provides some cues for revealing the regulation of latex metabolism in rubber trees. PMID:29163621

  15. Transcript Profiling of Hevea brasiliensis during Latex Flow

    Directory of Open Access Journals (Sweden)

    Jinquan Chao

    2017-11-01

    Full Text Available Latex exploitation enhances latex regeneration in rubber trees. The latex exploitation-caused latex flow lasts from 10 min to a few hours, which is convenient for exploring the transcript profiling of latex metabolism-related genes at the different stages of latex flow. In the present study, the expression pattern of 62 latex metabolism-related genes involved in water transportation, carbohydrate metabolism, natural rubber biosynthesis, hormone signaling, ROS generation and scavenging, and latex coagulum across three stages of latex flow between rubber tree clones CATAS7-33-97 and CATAS8-79 were comparatively analyzed by quantitative real-time PCR. The two clones show differences in latex regeneration and have a different duration of latex flow. The results showed that the expression levels of 38 genes were significantly higher in CATAS8-79 latex than in CATAS7-33-97 during latex regeneration, while 45 genes had a notably higher expression level in CATAS8-79 latex during latex flow. Together with the activation of the MEP pathway and jasmonate pathway in CATAS8-79 latex, HbPIP1;3, HbPIP1;4, HbSUT3, HbSus3, HbHMGS1-2, HbMK should contribute to the high latex regeneration ability. The up-regulation of ethylene signaling and Hb44KD and the down-regulation of latex coagulation-related genes in CATAS8-79 latex might contribute to its longer latex flow duration. This study provides some cues for revealing the regulation of latex metabolism in rubber trees.

  16. Allergenicity of latex rubber products used in South African dental ...

    African Journals Online (AJOL)

    Background. Latex sensitisation is recognised as a health problem among health care workers (HCWs) using latex products. The aim of this study was to quantify specific latex allergens in latex devices used in South African academic dental schools. The current study also compared the total protein content and the levels of ...

  17. Reinforcement of latex rubber by the incorporation of amphiphilic particles

    Science.gov (United States)

    Latex rubbers are fabricated from latex suspensions. During the fabrication process, latex particles are bound together while water is removed from the suspension. This report shows that the mechanical properties of latex rubbers can be improved by incorporating a small amount of amphiphilic submicr...

  18. [Latex allergy in a population at risk].

    Science.gov (United States)

    Ruiz Fernández, M; Flores Sandoval, G; Orea Solano, M

    1999-01-01

    The allergy to latex is an illness whose prevalence has been increased in very significant form in the last years. To know the allergy incidence to latex in population of risk, as well as to identify the related sintomatology and the importance or paper that play the atopia antecedents and time of contact with latex for the development of the illness. We carry out a prospective, descriptive, experimental and traverse study in population of risk, in the service of Allergy and clinical Immunology of the Hospital Regional Lic. Adolfo López Mateos, ISSSTE. One hundred patients of both sexes were included, with age of 20 to 50 years, with the antecedent of being personal medical and paramedic and to have presented contact with latex material in a minimum period of one year. They were carried out clinical history with registration of sintomatology nasal, bronchial, cutaneous and associated to contact with latex. They were carried out cutaneous test for prick to latex with positive control with the help of histamine solution and negative control with solution of Evans and immediate reading of the same one. 22% of the patients in study, they presented positive skin test latex, with a time of exhibition 10 year-old average, 68% presented antecedent of atopy personal, family and, likewise the associate sintomatology was in a 33.3% dermatology, 54.5 nasal, nobody presented bronchial symptoms and a 9% asymptomatic was reported. We support that the immediate skin test latex for Prick is an important parameter of support diagnosis for allergy to type 1 latex.

  19. Catalysis by Polymer Latexes and Dendrimers

    National Research Council Canada - National Science Library

    Ford, Warren

    1999-01-01

    ... were shown to depend mainly on the ability of the latex to sorb the organic reactant from water. The catalysts were active for hydrolysis of organophosphates in aqueous NaOH at phosphate concentrations as high...

  20. Microfabricated Passive Magnetic Bead separators

    DEFF Research Database (Denmark)

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

    2006-01-01

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

  1. Microfluidic magnetic bead conveyor belt.

    Science.gov (United States)

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

    2017-11-07

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

  2. Low prevalence of latex allergy in children with spinal dysraphism in non-latex-free environment.

    Science.gov (United States)

    Goldberg, Hanan; Aharony, Shachar; Levy, Yael; Sivan, Bezalel; Baniel, Jack; Ben Meir, David

    2016-02-01

    Studies in the past have shown that children with spinal dysraphism have highly prevalent latex allergy. These children have a spectrum of congenital spinal anomalies, caused by defects in neural tube closure, with an incidence of 1 in 1000 births. Proposed risk factors for latex allergy include multiple surgeries since birth, including an insertion of a ventriculoperitoneal shunt, elevated IgE titers, repeat multiple catheterizations, and atopy. In the 1990 s, studies published in the United States and Europe showed a latex allergy prevalence of over 70% in these patients. On the other hand, studies published years later in other countries showed a declining prevalence of no more than 17%. Our goal was to prospectively assess the prevalence of latex allergy in children with spinal dysraphism in our non-latex free environment center compared with a control group. The study group included 58 children with spinal dysraphism attending our center between 2010 and 2013. Findings were compared to 65 children referred for evaluation of allergic diseases. The parents completed questionnaires assessing personal and familial history of allergic diseases. All children were tested for blood latex IgE-specific antibodies (IMMULITE 2000). The mean age was 120.9 (67.6) months in the study group and 129.5 (68.5) months in the control group (p = 0.27). The corresponding median number of surgical procedures was 2 (range 0-10) and 0 (range 0-4), and mean duration of clean intermittent catheterization was 52 (72.2) months in the study group. Positive IgE antibodies and clinical allergic reactions were low with very similar prevalence in both groups (Figure). Our results show considerable lower latex allergy and sensitization than studies published in the United States and Europe in the past, despite the fact that our center utilizes minimal avoidance measures for latex allergy. Study limitations include the relatively small number of patients in our single-center study. Moreover, our

  3. Hypersensitivity to latex and Ficus benjamina allergens.

    Science.gov (United States)

    Delbourg, M F; Moneret-Vautrin, D A; Guilloux, L; Ville, G

    1995-12-01

    Association between allergy to Ficus benjamina and Hevea brasiliensis, two botanically unrelated plants, was suspected in consequence of two clinical observations. Symptoms were rhinitis and asthma. This study was undertaken to assess the in vivo and in vitro cross-reactivity between Ficus benjamina and Hevea brasiliensis allergens. The two patients were asked about use and contact with latex devices and relationship between symptoms and Ficus benjamina exposure. Skin prick tests were performed with Ficus benjamina, Hevea brasiliensis extracts and common allergens. Double-blind nasal and bronchial challenge tests were done using the rinse fluid from a brand of latex gloves. Total and specific IgE antibodies to Ficus benjamina and Hevea brasiliensis were determined. In vitro cross-reactivity was investigated by means of CAP RAST and immunodot inhibition experiments. We observed that for the first patient the primary phenomenon is probably allergy to latex followed by allergy to Ficus benjamina. For the second patient, allergy to Ficus benjamina was diagnosed (improvement related to the avoidance of exposure to Ficus benjamina allergens) and positivity to latex skin prick tests may be due to the cross-reacting allergens. In vitro assays showed specific IgE antibodies to both allergens and cross-reactivity was confirmed in the two cases by reciprocal inhibition of the two extracts. The increasing risk of sensitization to widely used latex devices and extensive exposure to Ficus species in households and offices indicates increased allergenic risk from this newly recognized cross-reactivity.

  4. Anticonvulsant action of Calotropis procera latex proteins.

    Science.gov (United States)

    Lima, Raquel Cristina de Sousa; Silva, Márcia Calheiros Chaves; Aguiar, Carlos Clayton Torres; Chaves, Edna Maria Camelo; Dias, Kátia Cilene Ferreira; Macêdo, Danielle Silveira; de Sousa, Francisca Cléa Florenço; Carvalho, Krishnamurti de Morais; Ramos, Márcio Viana; Vasconcelos, Silvânia Maria Mendes

    2012-02-01

    Calotropis procera (Ait.) R.Br. is a laticiferous plant belonging to the Apocynaceae family. C. procera latex proteins were evaluated with respect to anticonvulsant and sedative activity in mouse models of pentylenetetrazol (PTZ)-, pilocarpine-, and strychnine-induced convulsions or turning behavior and pentobarbital-induced sleep. In the strychnine- and pilocarpine-induced seizure models, C. procera latex proteins caused no significant alterations in latencies to convulsions and death, as compared with controls. In the PTZ-induced seizure model, administration of C. procera latex proteins in high doses (50 or 100mg/kg) and diazepam caused significant increases in latencies to convulsions and death. C. procera latex proteins (50 or 100mg/kg) and 2mg/kg diazepam caused a decrease in sleep latency and an increase in sleep time compared with the control group and groups treated with 5 or 10mg/kg. Our results suggest that C. procera latex proteins have a central nervous system-depressant activity as reflected in their potentiation of pentobarbital-induced sleeping time and their anticonvulsant action in the PTZ-induced seizure model. Copyright © 2011 Elsevier Inc. All rights reserved.

  5. The Morphology of Emulsion Polymerized Latex Particles

    Science.gov (United States)

    Wignall, G. D.; Ramakrishnan, V. R.; Linne, M. A.; Klein, A.; Sperling, L. H.; Wai, M. P.; Gelman, R. A.; Fatica, M. G.; Hoerl, R. H.; Fisher, L. W.

    1987-11-01

    Under monomer starved feed conditions, emulsion polymerization of perdeuterated methyl methacrylate and styrene in the presence of preformed polymethylmethacrylate latexes resulted in particles with a core-shell morphology, as determined by small-angle neutron scattering (SANS) analysis for a hollow sphere. The locus of polymerization of the added deuterated monomer is therefore at the particle surface. In similar measurements a statistical copolymer of styrene and methyl methacrylate was used as seed particles for further polymerization of trideuteromethyl methacrylate. The resulting polymer latex was again shown to have a core-shell morphological structure as determined by SANS. SANS experiments were also undertaken on polystyrene latexes polymerized by equilibrium swelling methods, with deuterated polymer forming the first or second step. The experiments covered a molecular weight range of 6 x 10{sup 4} 10{sup 6} the molecular weights are consistent with the experimental errors, indicating that the deuterium labeled molecules are randomly distributed in the latex. These results led to the finding that the polymer chains were constrained in the latex particles by factors of 2 to 4 from the relaxed coil dimensions. For M < 10{sup 6} g/mol SANS gave zero angle scattering intensities much higher than expected on the basis of a random distribution of labeled molecules. Several models were examined, including the possible development of core-shell structures at lower molecular weights.

  6. The morphology of emulsion polymerized latex particles

    Energy Technology Data Exchange (ETDEWEB)

    Wignall, G.D.; Ramakrishnan, V.R.; Linne, M.A.; Klein, A.; Sperling, L.H.; Wai, M.P.; Gelman, R.A.; Fatica, M.G.; Hoerl, R.H.; Fisher, L.W.

    1987-11-01

    Under monomer starved feed conditions, emulsion polymerization of perdeuterated methyl methacrylate and styrene in the presence of preformed polymethylmethacrylate latexes resulted in particles with a core-shell morphology, as determined by small-angle neutron scattering (SANS) analysis for a hollow sphere. The locus of polymerization of the added deuterated monomer is therefore at the particle surface. In similar measurements a statistical copolymer of styrene and methyl methacrylate was used as seed particles for further polymerization of trideuteromethyl methacrylate. The resulting polymer latex was again shown to have a core-shell morphological structre as determined by SANS. SANS experiments were also undertaken on polystyrene latexes polymerized by equilibrium swelling methods, with deuterated polymer forming the first or second step. The experiments covered a molecular weight range of 6 x 10/sup 4/ < M < 6 x 10/sup 6/ g/mol. For M > 10/sup 6/ the molecular weights are consistent with the experimental errors, indicating that the deuterium labeled molecules are randomly distributed in the latex. These results led to the finding that the polymer chains were constrained in the latex particles by factors of 2 to 4 from the relaxed coil dimensions. For M < 10/sup 6/ g/mol SANS gave zero angle scattering intensities much higher than expected on the basis of a random distribution of labeled molecules. Several models were examined, including the possible development of core-shell structures at lower molecular weights. 25 refs., 6 figs., 3 tabs.

  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. LaTeX for Agricultural Extension Professionals

    Science.gov (United States)

    LaTeX is a free open source document preparation system for professional quality documents and presentation materials. Extension professionals, trying to reach their audience though various forms of printed and online resources, can benefit from the vast potential of LaTeX. Using LaTeX empowers the ...

  9. TRITERPENE COMPOUNDS FROM THE LATEX OF FICUS SUR I ...

    African Journals Online (AJOL)

    Two pentacyclic triterpenoids of oleanane and ursene structures have been isolated from the latex of the Ficus sur. The compounds isolated from the latex are naturally acetylated in the 3-position and their structures have been elucidated on the basis of spectroscopic studies. KEY WORDS: Latex, Ficus sur, Moraceae, ...

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

    Science.gov (United States)

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

    2017-04-01

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

  11. Calibration beads containing luminescent lanthanide ion complexes

    Science.gov (United States)

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

  12. Emotion with tears decreases allergic responses to latex in atopic eczema patients with latex allergy.

    Science.gov (United States)

    Kimata, Hajime

    2006-07-01

    Allergic responses are enhanced by stress, whereas they are reduced by laughter in atopic eczema patients. Emotion with tears decreases plasma IL-6 levels in patients with rheumatoid arthritis. Thus, the effect of emotion with tears on allergic responses in patients with atopic eczema was studied. Sixty patients with atopic eczema having latex allergy viewed both the weather information video and the heart-warming movie, Kramer vs. Kramer. Just before and immediately after viewing each video, allergic responses to latex were measured. Viewing the weather information video did not cause emotion with tears in any patients, and it failed to modulate allergic responses. In contrast, viewing Kramer vs. Kramer caused emotion with tears in 44 of 60 patients, and it reduced allergic skin wheal responses to latex and latex-specific IgE production in them. Emotion with tears reduced allergic responses, and it may be useful in the treatment of allergic diseases.

  13. Exploiting epoxidized natural rubber latex (ENRL) as a starting raw material for latex-based products

    Science.gov (United States)

    Siti Nor Qamarina, M.; Fatimah Rubaizah, M. R.; Nurul Suhaira, A.; Norhanifah, M. Y.

    2017-12-01

    Epoxidized natural rubber latex (ENRL) is a chemically modified natural rubber latex produced from epoxidation process that involves usage of organic peracids. Conversion of the ENRL into dry rubber products has been known to exhibit many beneficial properties, however limited published works were found on diversifiying the ENRL latex-based products applications. In this preliminary work, different source of raw materials and neutralization systems were investigated. The objective was to explore possibilities in producing distinctive ENRL. Findings have demonstrated that different source of raw materials and neutralization systems influenced the typical ENRL specifications, stability behavior and particle size distribution. Morphological observations performed on these ENRL systems appeared to agree with the ENRL characteristics achieved. Since experimenting these two main factors resulted in encouraging ENRL findings, detailed work shall be further scrutinized to search for an optimum condition in producing marketable ENRL specifically for latex-based products applications.

  14. Latex glove sensitivity amongst diagnostic imaging healthcare ...

    African Journals Online (AJOL)

    ... gloves prior to this investigation. The paper concludes that latex hypersensitivity is a real problem amongst diagnostic imaging healthcare personnel in our locality. This preliminary work, therefore, provides the basis of a much larger controlled study in the future. African Journal of Health Sciences Vol. 15 (1&2) 2008: pp.

  15. Latex allergy in dentistry: clinical cases report

    NARCIS (Netherlands)

    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

  16. Shear viscosity of an ordering latex suspension

    NARCIS (Netherlands)

    van der Vorst, A.M.; van der Vorst, B.; van den Ende, Henricus T.M.; Aelmans, N.J.J.; Mellema, J.

    1997-01-01

    The shear viscosity of a latex which is ordered at rest is studied as a function of the shear rate and volume fraction. At low shear rates and for moderate to high volume fractions, the flow curves show dynamic yield behavior which disappears below a volume fraction of 8%. At high shear rates, the

  17. Ficus sycomorus latex: A thermostable peroxidase | Mohamed ...

    African Journals Online (AJOL)

    Peroxidase from sycamore fig Ficus sycomorus latex (POLI) was purified by heat treatment, anion exchange chromatography and molecular exclusion chromatography. The purity was determined from high specific activity (9166 units/mg protein), purification fold (28), RZ value 3.1 and a single band in native polyacrylamide ...

  18. Latex glove sensitivity amongst diagnostic imaging healthcare ...

    African Journals Online (AJOL)

    kemrilib

    Sciences, Faculty of Health Sciences and Technology, University of Nigeria, Enugu Campus, Enugu. State, Nigeria. ezecharlesu@yahoo.com. SUMMARY. The paper ... of the respondents had previous knowledge of hypersensitivity reaction to latex gloves prior to ... radiology staff in the five Southeastern states of Nigeria ...

  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. Magnetic bead detection using nano-transformers.

    Science.gov (United States)

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

    2010-11-19

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

  1. Force decay of latex and non-latex intermaxillary elastics: a clinical study.

    Science.gov (United States)

    Pithon, Matheus Melo; Mendes, Jéssica Lima; da Silva, Camila Anselmo; Lacerda Dos Santos, Rogério; Coqueiro, Raildo da Silva

    2016-02-01

    To evaluate force decay between intermaxillary orthodontic elastics with and without latex in the oral medium at different time intervals. Intermaxillary orthodontic elastics with and without latex [1/8″ (3.2mm), 1/4″ (6.35mm), and 5/16″ (7.94mm) in diameter] were evaluated 'clinically'. For this purpose, 26 patients served as hosts for the elastics during the evaluation period. Initially, 52 thermoplasticized plates 1mm thick were made according to the patients' mould. Then, the orthodontic accessories were bonded to the plates, which kept the elastics distended throughout the experimental period. The force released by the elastics at this distance was evaluated at 0, 12, and 24 hours. Statistical analyses were performed using the Friedman, Wilcoxon, and Mann-Whitney tests (significance set at 5 per cent). Elastics with and without latex presented with permanent deformation and increasing internal diameter throughout the entire period. Elastics with latex, 1/8″ (3.2mm) in diameter, sustained higher levels of force than those without latex. Elastics measuring 1/4″ (6.35mm) and 5/16″ (7.94mm) in diameter without latex sustained higher levels of force at 0 and 12 hours compared to those with latex. At the end of the experiment (24 hours), no significant difference was observed between the elastics (P > 0.05). This study only evaluated three time intervals: 0, 12, and 24 hours. If the behaviour was evaluated at different time intervals, different behaviours of these materials might be revealed. Elastics with latex 1/8″ in diameter sustained a higher level of final force than the corresponding type without latex. The 1/4 and 5/16 elastics with and without latex were not different at the end of the evaluation period. © The Author 2015. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  2. Direct friction measurement in draw bead testing

    DEFF Research Database (Denmark)

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

    2005-01-01

    The application of draw beads in sheet metal stamping ensures controlled drawing-in of flange parts. Lubrication conditions in draw beads are severe due to sliding under simultaneous bending. Based on the original draw bead test design by Nine [1] comprehensive studies of friction in draw beads...... have been reported in literature. A major drawback in all these studies is that friction is not directly measured, but requires repeated measurements of the drawing force with and without relative sliding between the draw beads and the sheet material. This implies two tests with a fixed draw bead tool...... and a freely rotating tool respectively, an approach, which inevitably implies large uncertainties due to scatter in the experimental conditions. In order to avoid this problem a new draw bead test is proposed by the authors measuring the friction force acting on the tool radius directly by a build...

  3. Effect of diphenyldisulphides with different substituents on the reclamation of NR based latex products

    NARCIS (Netherlands)

    Rajan, V.V.; Dierkes, Wilma K.; Joseph, R.; Noordermeer, Jacobus W.M.

    2007-01-01

    The latex industry has expanded over the years to meet the world demands for gloves, condoms, latex thread etc. Because of the strict specifications for the products and the unstable nature of the latex, as high as 15% of the final latex products are rejected. Since waste latex rubber (WLR)

  4. [Latex. An important aeroallergen involved in occupational asthma].

    Science.gov (United States)

    Quirce, S; Olaguíbel, J M; Alvarez, M J; Tabar, A I

    2003-01-01

    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 of exposure to latex are not applied.

  5. Identification and practical management of latex allergy in occupational settings.

    Science.gov (United States)

    Caballero, María Luisa; Quirce, Santiago

    2015-01-01

    Allergy to natural rubber latex (NRL) from Hevea brasiliensis is a relevant occupational health hazard. The use of gloves and products manufactured with latex and environmental allergen exposure in the work environment are risks factors for the development of occupational allergy among different job categories. Healthcare workers have been the most commonly affected, but other professions with exposure to latex products such as hairdressers, cleaners, food handlers and those making natural rubber latex (NRL) products are also at risk of developing occupational allergy. Clinical manifestations of IgE-mediated latex allergy can range from troublesome skin disorders to life-threatening systemic reactions. It is very important to identify the occupational allergic diseases in their early stages in order to implement avoidance strategies. For this purpose, the interventions for prevention should emphasize the importance of latex allergy awareness and surveillance among exposed workforces.

  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......), 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. Subconjunctival latex paint from occupational injury.

    Science.gov (United States)

    Odhav, Ashika; Kollipara, Ramya; Teymoorian, Savak; Lord, Ron K; Lyon, David B

    2013-05-01

    Accidental eye trauma with spray guns are rare, but potentially very serious, injuries. Although it is agreed that these injuries require immediate and vigorous therapy, the specifics of such therapy are poorly defined. With latex paint sprayer injuries to hands and extremities, resulting chemical-induced inflammation, high-pressure necrosis, ischemic necrosis, and gangrene require surgical debridement and possibly, amputation. With eye injuries, treatment is directed at preservation of vision, as there is a potential risk of visual loss. There is currently no consensus on optimal treatment of ocular spray paint injuries. Here we propose a management approach to ocular spray paint injuries with a successful outcome in the case reported. We report the first case, to our knowledge, of an industrial airless spray gun injury that resulted in subconjunctival deposition of latex paint in a soft contact lens wearer. Vision was preserved with medical management consisting of irrigation and topical corticosteroids, antibiotics and cycloplegics. Although latex paint spray gun injuries to the eye are not encountered frequently in practice, this case shows that conservative medical management with no surgical intervention is effective for ocular injuries with preserved vision. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. Shear Driven Aggregation in Latex Colloids

    Science.gov (United States)

    Ahuja, Suresh

    2013-03-01

    Reynolds number is small in colloidal flow and therefore, colloidal volume fraction and Peclet number are important. AS the volume fraction and attractive coupling between particles increase, relaxation time and Weisenberg number become significant. Shear-induced aggregation of latex colloids is due to the interplay between the shear-induced formation and breakage of latex.particles. While particle size is limited by breakage, their number density increases with the shearing-time. Upon cessation of shear, the particles interconnect into an assembly held by grainy bonds. It results in increase in yield stress and dynamic modulus. A contact model enables aggregates maintaining their structures under low stress while being restructured under high stress. Modeling involves solution of Navier- Stokes equation with moving particles as boundary condition for the flow like using the Lattice Boltzmann approach or by using (accelerated) Stokesian Dynamics. Alternate approach is to model the fluid phase by soft repulsive particles with pair-wise noise and friction, known as dissipative particle dynamics (DPD). This method by construction produces full inertial hydrodynamics, but applying the correct fluid-particle boundary condition is non-trivial. Both particle to particle and particle to wall collisions can be considered using Johnson-Kendall- Roberts (JKR) analysis of collision dynamics of dissipative forces using a soft-sphere modeling technique. Our experimental work used emulsion polymerized latex that was subjected to steady and dynamic shear. Yield stress, dynamic modulus and relaxation time increased on shearing in conjunction with changes in aggregate size.

  9. Production of latex agglutination reagents for pneumococcal serotyping.

    Science.gov (United States)

    Ortika, Belinda D; Habib, Maha; Dunne, Eileen M; Porter, Barbara D; Satzke, Catherine

    2013-02-05

    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. 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. 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 time, making them ideal for use in low-income countries.

  10. Fluorescent Beads Are a Versatile Tool for Staging Caenorhabditis elegans in Different Life Histories

    Directory of Open Access Journals (Sweden)

    Liberta Nika

    2016-07-01

    Full Text Available Precise staging of Caenorhabditis elegans is essential for developmental studies in different environmental conditions. In favorable conditions, larvae develop continuously through four larval stages separated by molting periods. Distinguishing molting from intermolt larvae has been achieved using transgenes with molting reporters, therefore requiring strain constructions, or careful observation of individuals for pharyngeal pumping or behavioral quiescence. In unfavorable conditions, larvae can enter the stress-resistant and developmentally arrested dauer larva stage. Identifying dauer larvae has been based on their ability to withstand detergent selection, precluding identification of recovering animals or of mutants with defects in dauer morphogenesis. Here, we describe a simple method to distinguish molting larvae or dauer larvae from intermolt larvae that bypasses the limitations of current methods. Fluorescent latex beads are mixed with the bacterial food source and ingested by intermolt larvae and adults. Molting and dauer larvae do not feed, and therefore lack beads in their digestive tract. The presence of beads can be determined using a dissecting microscope at magnifications as low as 100 ×, or by using a wormsorter for high-throughput experiments. We find that continuously developing bead-lacking larvae display hallmarks of molting, including expression of the mlt-10::gfp molting marker and a lack of pharyngeal pumping. Furthermore, wild-type and mutant dauer larvae produced by any of three common methods are accurately identified by a lack of beads. Importantly, this method is effective in SDS-sensitive mutant backgrounds and can identify recovering dauer larvae, a stage for which there is no other method of positive selection.

  11. Follow-up Study of Latex-allergic Health Care Workers in Japan

    Directory of Open Access Journals (Sweden)

    Akiko Yagami

    2006-01-01

    Conclusions: After avoiding latex products and following our educational suggestions, the patients' allergy symptoms had generally improved. This indicates that our countermeasures against latex allergy were largely successful.

  12. Photochemical and chemical transformation of Calotropis procera latex towards obtaining value added chemicals and fuels

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, D.K.; Arora, M.; Behera, B.K. [Indian Institute of Technology, Delhi (India). Centre for Energy Studies

    1996-12-31

    Photothermal degradation of the latex obtained from Calotropis procera showed enhanced extraction in heptane up to 50%. Treatment of the latex with different concentrations of NaOH resulted in the reduction in heptane extraction of the latex. Treatment of latex with aqueous HCl coagulated it, resulting in an increase in extraction yield. The {sup 1}HNMR, {sup 13}CNMR and FTIR spectral analyses of treated latex showed an increase in the olefinic and carbonyl groups in the latex. This showed that photothermal treatments rendered the latex more amenable to hydrocracking for obtaining value added chemicals and fuels from the latex. 13 refs., 2 tabs.

  13. 21 CFR 801.435 - User labeling for latex condoms.

    Science.gov (United States)

    2010-04-01

    ... (CONTINUED) MEDICAL DEVICES LABELING Special Requirements for Specific Devices § 801.435 User labeling for... over time. To protect the public health and minimize the risk of device failure, latex condoms must... spermicidal stability testing is different from the expiration date based upon latex integrity testing, the...

  14. Antimicrobial activity of latex silver nanoparticles using Calotropis procera

    Directory of Open Access Journals (Sweden)

    Nadia Hussein Mohamed

    2014-11-01

    Conclusions: It can be concluded that serum latex of Calotropis procera was found to display strong potential for the synthesis of AgNPs as antimicrobial agents through rapid reduction of silver ions (Ag+ to Ag0. The green synthesized AgNPs were found to show higher antimicrobial efficacy than crude latex.

  15. High concentrations of natural rubber latex allergens in gloves used ...

    African Journals Online (AJOL)

    gloves to be purchased from prospective suppliers of new gloves ... The price of latex gloves ranged from R0.26 to R11.30 per pair in January 2011. ... In addition, penetration of allergens through compromised skin .... Mabe DO, Singh TS, Bello B, Jeebhay MF, Lopata AL, Wadee A. Allergenicity of latex rubber products.

  16. Home Healthcare Workers: How to Prevent Latex Allergies

    Science.gov (United States)

    ... polymer gloves appropriate for infectious materials. • Provide reduced-protein, powder-free gloves, if latex gloves are selected for ... offer protection against infectious materials. • Ask for reduced-protein, powder-free gloves, if your employer supplies latex gloves. • ...

  17. Installing fonts in LaTeX a user's experience

    NARCIS (Netherlands)

    Hanssen, F.T.Y.

    2003-01-01

    This paper presents a user's experience with installing fonts for use in LaTeX. It will be shown that it is not hard to make a standard Type 1 font work, if you use modern font installation software for LaTeX. All the steps necessary to install the example fonts will be shown. The example fonts used

  18. Terpenoid compounds from the latex of Euphorbia drupifera ...

    African Journals Online (AJOL)

    This study aimed at the isolation and characterization of terpenoid compounds from the latex of Euphorbia drupifera. Methylated spirit extract of the latex was suspended in aqueous methanol and partitioned with petroleum spirit. The aqueous methanol residue was washed with ether. The ethereal fraction was subjected to ...

  19. A comparison of different LaTeX programs

    NARCIS (Netherlands)

    Koning, Ruud H.

    2001-01-01

    In this review two commercial and two freeware LaTeX implementations are discussed and compared: teTeX (Linux, Unix) pcTeX32 (Windows 3.1, Windows95/98/NT) Scientific Workplace (Windows95/98/NT) mikTeX (Windows95/98/NT) Keywords: LaTeX, word processing

  20. Assessing the potency of Pedilanthus tithymaloides latex against ...

    African Journals Online (AJOL)

    The latex of Pedilanthus tithymaloides is used in traditional medicine for treating malaria attack. This usage was investigated by testing for in vivo antiplasmodial activity of the latex against Plasmodium berghei berghei in mice. Curative effect against established infection and suppressive activity against earlier infection of ...

  1. Antimalarial Anthrone and Chromone from the Leaf Latex of Aloe ...

    African Journals Online (AJOL)

    In Ethiopian traditional medicine, the leaf latex of Aloe debranan Chrstian is used for the treatment of several diseases including malaria. In an ongoing search for effective, safe and cheap antimalarial agents from plants, the leaf latex of A. debrana was tested for its in vivo antimalarial activity, in a 4-day suppressive assay ...

  2. Acute Toxicity of Crude Euphorbia tirucalli Latex Extracts to ...

    African Journals Online (AJOL)

    Acute toxicity of crude Euphorbia tirucalli latex extracts to Oreochromis niloticus juveniles was investigated in the College of Agriculture, Lafia. A four day static acute toxicity test was performed to determine the LC50 value of crude Euphorbia tirucalli latex extract for the fresh water fish, Oreochromis niloticus. Various ...

  3. A Protease Isolated from the Latex of Plumeria rubra Linn ...

    African Journals Online (AJOL)

    Purpose: To isolate, purify and characterize protease from the latex of the plant. Methods: Protease was isolated from the latex of Plumeria rubra Linn using acetone precipitation method and purified by a sequence of DEAE cellulose column chromatography, followed by two successive column purification in Sephadex G-50 ...

  4. The Latex Of Jatropha Curcas Linn (Euphorblaceae): A Prospective ...

    African Journals Online (AJOL)

    The latex of Jatropha curcas Linn (Euphorbiaceae) has been investigated as a prospective haemostatic agent. The latex reduced clotting and bleeding times significantly (P<0.0001) compared to Tincture of Benzoin Co (TBC); Iodine tincture, Tannin and 90%v/v Ethanol. There was a significant positive correlation between ...

  5. Latex allergy in an infant with acquired hydrocephalus | Ehiozw ...

    African Journals Online (AJOL)

    Latex allergy is a potentially life-threatening intraoperative occurrence which is relatively rare in our environment. We report the case of a 3 month old male infant with acquired hydrocephalus undergoing ventriculo-peritoneal shunt insertion who developed wheals and suffered a respiratory arrest following contact with latex ...

  6. Assessment of adverse reactions to latex gloves use among nurses ...

    African Journals Online (AJOL)

    Adverse reaction to latex is a common problem among nurses and other health care workers. The aim of the present study was to determine the prevalence of adverse reactions to latex amongst nurses at Mankweng Hospital. A cross sectional study was carried out amongst 235 nurses at Mankweng Hospital using a ...

  7. Incidence of latex harvesting technologies on agronomic and ...

    African Journals Online (AJOL)

    The experimental design was a randomized complete blocks with different latex harvesting technologies. The estimated parameters were rubber yield, radial vegetative growth, physiological profile and the profitability of applied latex harvesting technologies. Results indicated that non-stimulated combined with high tapping ...

  8. Expanded polylactide bead foaming - A new technology

    Science.gov (United States)

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

    2015-05-01

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

  9. Bead mediated separation of microparticles in droplets.

    Directory of Open Access Journals (Sweden)

    Sida Wang

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

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

    African Journals Online (AJOL)

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

  11. Syntheses of crosslinked latex nanoparticles using differential microemulsion polymerization

    Science.gov (United States)

    Hassmoro, N. F.; Rusop, M.; Abdullah, S.

    2013-06-01

    The differential microemulsion polymerization was used to synthesize latex nanoparticles. In this paper, 1, 3-butylene glycol dimethacrylate (1, 3-BGDMA) was used as a crosslinker respectively 1-5 weight% of monomer total. Butyl acrylate (BA), butyl methacrylate (BMA), and methacrylic acid (MAA) was used as the monomer. The thin film of latex nanoparticles were prepared by using spin coating method and have been dried at 100°C for 5 minutes. The amount of the crosslinker added in the polymerization was optimized and we found that the particle sizes fall in the range of 30-60 nm. The structural morphology of the uncrosslinked latex represented the most homogeneous image compared to the crosslinked latex. The effect of the amount of crosslinker on the particle sizes investigated by the Zeta-sizer Nano series while Atomic Force microscopy (AFM) was used to study the structural properties of latex nanoparticles.

  12. Polyphenoloxidase silencing affects latex coagulation in Taraxacum species.

    Science.gov (United States)

    Wahler, Daniela; Gronover, Christian Schulze; Richter, Carolin; Foucu, Florence; Twyman, Richard M; Moerschbacher, Bruno M; Fischer, Rainer; Muth, Jost; Prüfer, Dirk

    2009-09-01

    Latex is the milky sap that is found in many different plants. It is produced by specialized cells known as laticifers and can comprise a mixture of proteins, carbohydrates, oils, secondary metabolites, and rubber that may help to prevent herbivory and protect wound sites against infection. The wound-induced browning of latex suggests that it contains one or more phenol-oxidizing enzymes. Here, we present a comprehensive analysis of the major latex proteins from two dandelion species, Taraxacum officinale and Taraxacum kok-saghyz, and enzymatic studies showing that polyphenoloxidase (PPO) is responsible for latex browning. Electrophoretic analysis and amino-terminal sequencing of the most abundant proteins in the aqueous latex fraction revealed the presence of three PPO-related proteins generated by the proteolytic cleavage of a single precursor (pre-PPO). The laticifer-specific pre-PPO protein contains a transit peptide that can target reporter proteins into chloroplasts when constitutively expressed in dandelion protoplasts, perhaps indicating the presence of structures similar to plastids in laticifers, which lack genuine chloroplasts. Silencing the PPO gene by constitutive RNA interference in transgenic plants reduced PPO activity compared with wild-type controls, allowing T. kok-saghyz RNA interference lines to expel four to five times more latex than controls. Latex fluidity analysis in silenced plants showed a strong correlation between residual PPO activity and the coagulation rate, indicating that laticifer-specific PPO plays a major role in latex coagulation and wound sealing in dandelions. In contrast, very little PPO activity is found in the latex of the rubber tree Hevea brasiliensis, suggesting functional divergence of latex proteins during plant evolution.

  13. Polyphenoloxidase Silencing Affects Latex Coagulation in Taraxacum Species1[W

    Science.gov (United States)

    Wahler, Daniela; Gronover, Christian Schulze; Richter, Carolin; Foucu, Florence; Twyman, Richard M.; Moerschbacher, Bruno M.; Fischer, Rainer; Muth, Jost; Prüfer, Dirk

    2009-01-01

    Latex is the milky sap that is found in many different plants. It is produced by specialized cells known as laticifers and can comprise a mixture of proteins, carbohydrates, oils, secondary metabolites, and rubber that may help to prevent herbivory and protect wound sites against infection. The wound-induced browning of latex suggests that it contains one or more phenol-oxidizing enzymes. Here, we present a comprehensive analysis of the major latex proteins from two dandelion species, Taraxacum officinale and Taraxacum kok-saghyz, and enzymatic studies showing that polyphenoloxidase (PPO) is responsible for latex browning. Electrophoretic analysis and amino-terminal sequencing of the most abundant proteins in the aqueous latex fraction revealed the presence of three PPO-related proteins generated by the proteolytic cleavage of a single precursor (pre-PPO). The laticifer-specific pre-PPO protein contains a transit peptide that can target reporter proteins into chloroplasts when constitutively expressed in dandelion protoplasts, perhaps indicating the presence of structures similar to plastids in laticifers, which lack genuine chloroplasts. Silencing the PPO gene by constitutive RNA interference in transgenic plants reduced PPO activity compared with wild-type controls, allowing T. kok-saghyz RNA interference lines to expel four to five times more latex than controls. Latex fluidity analysis in silenced plants showed a strong correlation between residual PPO activity and the coagulation rate, indicating that laticifer-specific PPO plays a major role in latex coagulation and wound sealing in dandelions. In contrast, very little PPO activity is found in the latex of the rubber tree Hevea brasiliensis, suggesting functional divergence of latex proteins during plant evolution. PMID:19605551

  14. Synthesis and characterization of novel polyacid-stabilized latexes.

    Science.gov (United States)

    Yang, Pengcheng; Armes, S P

    2012-09-18

    A series of novel polyacid macromonomers based on 2-hydroxypropyl methacrylate (HPMA) were prepared by atom transfer radical polymerization (ATRP) via a two-step route. First, a range of well-defined PHPMA homopolymer precursors were synthesized by ATRP using a tertiary amine-functionalized initiator, 2-(dimethylamino)ethyl-2-bromoisobutyrylamide, and a CuCl/2, 2'-bipyridine (bpy) catalyst in alcoholic media at 50 °C. ATRP polymerizations were relatively slow and poorly controlled in pure isopropanol (IPA), especially when targeting higher degrees of polymerization (DP > 30). Improved control was achieved by addition of water: low polydispersity (M(w)/M(n) emulsion polymerization or alcoholic dispersion polymerization conditions. Near-monodisperse polystyrene latexes were obtained via aqueous emulsion polymerization using 10 wt % PSPMA macromonomer (with respect to styrene monomer) with various initiators as evidenced by scanning electron microscopy, disk centrifuge photosedimentometry and light scattering studies. PSPMA macromomer concentrations as low as 1.0 wt % also produced near-monodisperse latexes, suggesting that these PSPMA macromonomers are highly effective stabilizers. Alcoholic dispersion polymerization of styrene conducted in various ethanol/water mixtures with 10 wt % PSPMA(50) macromonomer produced relatively large near-monodisperse latexes. Increasing the water content in such formulations led to smaller latexes, as expected. Control experiments conducted with 10 wt % PSPMA(50) homopolymer produced relatively large polydisperse latexes via emulsion polymerization and only macroscopic precipitates via alcoholic dispersion polymerization. Thus the terminal styrene group on the macromonomer chains is essential for the formation of well-defined latexes. FT-IR spectroscopy indicated that these latexes contained PSPMA macromonomer, whereas (1)H NMR spectroscopy studies of dissolved latexes allowed stabilizer contents to be determined. Aqueous

  15. Experimental investigation of the effect of latex solid/water ratio on latex modified co-matrix mechanical properties

    Directory of Open Access Journals (Sweden)

    Ahmed M. Diab

    2013-03-01

    Full Text Available Numerous researches were performed on latex modified concretes and associated properties, however; some vital factors were not given attention in previous works. This study focus on new factor which significantly affects the properties of latex modified cement paste, mortar or concrete. This factor is termed as ‘latex solid/water ratio’ which is defined herein as the ratio of weight of solid latex to weight of total water content of cement composite including the water in latex itself. The effect of this factor on some properties of cement paste, mortar and concrete were experimentally evaluated. Properties of cement paste include the produced calcium hydroxide and ettringite content during hydration process, while those of cement mortar take account of absorption and effect of temperature on compressive strength. Furthermore, the effect of this factor on the compressive and flexural strengths, modulus of elasticity, water penetration depth and drying shrinkage of concrete were explored. Based on experimental evidences, and spite of using different cement contents, sources of latex, water–cement ratios and slump values, it can be generally concluded that the latex solid/water ratio is a dominant factor affecting different properties of latex modified mortars and concrete.

  16. Latex symptoms and sensitisation in health care workers.

    Science.gov (United States)

    Larese Filon, F; Bosco, A; Fiorito, A; Negro, C; Barbina, P

    2001-04-01

    Natural rubber latex has become an important occupational health concern, particularly among health care workers, who for protection are required to wear latex gloves when at work. This study evaluated the prevalence of latex-related symptoms and sensitisation among a large group of health care workers in Trieste hospitals. We evaluated the prevalence of latex-related symptoms in 1,165 health care workers, by means of a questionnaire, a medical examination, skin prick tests and IgE-specific evaluation. We determined atopy and latex sensitivity by skin prick tests using a battery of common inhalant allergens, a commercial latex extract (Lofarma Allergeni, Milan) and individual skin puncture tests for each of the vegetables immunologically related to latex (potato, tomato, chestnut, banana, kiwi fruit). Associations between potential risk factors for latex allergy were assessed. Glove-related symptoms were noticed on 17.2% of the nurses (200) the majority of symptoms being mild dermatitis with itching and erythema (120 subjects, 11.1%). Symptoms suggestive of IgE-mediated latex allergy were found in 51 subjects: 35 (3%) complained of contact urticaria and 16 (2.2%) complained of asthma and/or rhinitis. The resulting symptoms were significantly related to skin prick tests that were positive to latex (odds ratio (OR) = 11.89; 6.40-22.2), to personal atopy (OR = 2.15; 1.47-3.12), to familiar atopy (OR = 2.12; 1.48-3.03), to skin prick test positivity to related fruit (OR = 2.01; 1.16-3.46) but not to prick test positivity to common inhalant allergens (OR = 1.00; 0.71-1.39). Symptoms increased as a direct function of the time-usage of latex gloves and were more prevalent in operating room staff. In this large cross-sectional study, glove-related symptoms and latex skin sensitisation appear to be substantial among health care workers, and are related to common signs of atopy. We stress the need of preventive measures to avoid latex exposure when health care workers are at

  17. Latex allergy in dental students: a cross-sectional study.

    Science.gov (United States)

    Vangveeravong, Mukda; Sirikul, Jintana; Daengsuwan, Tassalapa

    2011-08-01

    Latex allergy is a major occupational health problem in health care workers who regularly use latex gloves. Dentists are one of the high risk groups for latex allergy and sensitization as it is generally found that healthcare workers (HCW) have 3 times greater prevalence of latex allergy. There are very few studies of latex allergy in HCW in Thailand. To study the prevalence of latex-related symptoms, latex-sensitization and possible risk factors in dental students. A cross-sectional study was performed on all dental students of the Faculty of Dentistry, Chulalongkorn University, during Dec 2007 to May 2008, using questionnaires and skin prick tests (SPT), using 3 latex extracts prepared from Proglove, Doctor Plus gloves and a commercial latex allergen (Stallergenes, France). SPT was done only in those who were willing and signed informed consents. There were 617 completed questionnaires (87.3%). The mean age of the volunteers was 20.9 +/- 1.7 years with 29.3% male and 70.7% female. The prevalence of latex glove-related symptoms was 5.0%. These symptoms were all local, cutaneous symptoms, ranging from hand pruritus (64.5%), hand eczema (19.4%) and contact urticaria (16.1%). Eight subjects (1.3%) reported pruritus or urticaria on exposure to other rubber products while 12 subjects (1.9%) reported reactions to some fruits. The risk factors for latex-glove allergy were personal history of allergic diseases (atopic dermatitis, urticaria, pruritus and rubber allergy), duration of using gloves more than 18 hours per week, more than 3 pairs of gloves used per day and timing of glove exposure. The 4th to 6th year students were observed significantly more prevalence of symptoms than the 1st to 3rd year students (OR, 3.69; 95% CI, 1.73-7.87; p = 0.0003). SPT for 3 extracts of latex was done in 247 cases (40.0%); overall latex sensitization rate was 14.2%. The commercial extract had higher incidence of latex sensitization compared to the 2 gloves extract. The 1st year

  18. 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.

  19. 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. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

    Haque, Emdadul; Makuuchi, Keizo; Ikeda, Kenichi; Yoshii, Fumio; Kume Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Mitomo, Hiroshi [Gunma Univ., Faculty of Engineering, Department of Biological and Chemical Engineering, Kiryu, Gunma (Japan)

    2001-03-01

    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)

  1. 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.

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

    Science.gov (United States)

    Bauer, Georg; Gorb, Stanislav N; Klein, Marie-Christin; Nellesen, Anke; von Tapavicza, Max; Speck, Thomas

    2014-01-01

    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.

  3. 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.

  4. Bacteriophage-based latex agglutination test for rapid identification of Staphylococcus aureus.

    Science.gov (United States)

    Idelevich, Evgeny A; Walther, Thomas; Molinaro, Sonja; Li, Xuehua; Xia, Guoqing; Wieser, Andreas; Peters, Georg; Peschel, Andreas; Becker, Karsten

    2014-09-01

    Rapid diagnosis is essential for the management of Staphylococcus aureus infections. A host recognition protein from S. aureus bacteriophage phiSLT was recombinantly produced and used to coat streptavidin latex beads to develop a latex agglutination test (LAT). The diagnostic accuracy of this bacteriophage-based test was compared with that of a conventional LAT, Pastorex Staph-Plus, by investigating a clinical collection of 86 S. aureus isolates and 128 coagulase-negative staphylococci (CoNS) from deep tissue infections. All of the clinical S. aureus isolates were correctly identified by the bacteriophage-based test. While most of the CoNS were correctly identified as non-S. aureus isolates, 7.9% of the CoNS caused agglutination. Thus, the sensitivity of the bacteriophage-based LAT for identification of S. aureus among clinical isolates was 100%, its specificity was 92.1%, its positive predictive value (PPV) was 89.6%, and its negative predictive value (NPV) was 100%. The sensitivity, specificity, PPV, and NPV of the Pastorex LAT for the identification of S. aureus were 100%, 99.2%, 98.9%, and 100%, respectively. Among the additionally tested 35 S. aureus and 91 non-S. aureus staphylococcal reference and type strains, 1 isolate was false negative by each system; 13 and 8 isolates were false positive by the bacteriophage-based and Pastorex LATs, respectively. The ability of the phiSLT protein to detect S. aureus was dependent on the presence of wall teichoic acid (WTA) and corresponded to the production of ribitol phosphate WTA, which is found in most S. aureus clones but only a small minority of CoNS. Bacteriophage-based LAT identification is a promising strategy for rapid pathogen identification. Finding more specific bacteriophage proteins would increase the specificity of this novel diagnostic approach. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

    Chirinos, H.; Lugao, A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

    2002-07-01

    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)

  6. [Drugs having latex and therapeutic alternatives in hospital formulary].

    Science.gov (United States)

    Damas Fuentes, Rosa María; Pérez León, Moisés; Piñero González, Marta; Sangil Monroy, Nayra; Molero Gómez, Rafael; Domínguez Lantigua, Pablo

    2015-01-01

    To analyze the latex content of drugs in hospital formulary and establish possible therapeutic alternatives. All drugs susceptible of having latex were selected and written information was obtained from manufacturers. A therapeutic alternative was found for each of them, if possible. Written information from manufacturer was obtained for 605 (97.9%) and from label information for 8 of 632 selected drugs. For 43.9% of not safe drugs (total 57) on patients with latex allergy, a therapeutic alternative was found in hospital formulary. Knowing drugs having latex improve the prescription security, while the therapeutic alternatives chart eases the validation. The published data updates the scarce and variable information for patients and healthcare professionals. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  7. 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...

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

    Science.gov (United States)

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

    2012-09-01

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

  9. Capsular Serotyping of Streptococcus pneumoniae by latex agglutination.

    Science.gov (United States)

    Porter, Barbara D; Ortika, Belinda D; Satzke, Catherine

    2014-09-25

    Latex agglutination reagents are widely used in microbial diagnosis, identification and serotyping. Streptococcus pneumoniae (the pneumococcus) is a major cause of morbidity and mortality world-wide. Current vaccines target the pneumococcal capsule, and there are over 90 capsular serotypes. Serotyping pneumococcal isolates is therefore important for assessing the impact of vaccination programs and for epidemiological purposes. The World Health Organization has recommended latex agglutination as an alternative method to the 'gold standard' Quellung test for serotyping pneumococci. Latex agglutination is a relatively simple, quick and inexpensive method; and is therefore suitable for resource-poor settings as well as laboratories with high-volume workloads. Latex agglutination reagents can be prepared in-house utilizing commercially-sourced antibodies that are passively attached to latex particles. This manuscript describes a method of production and quality control of latex agglutination reagents, and details a sequential testing approach which is time- and cost-effective. This method of production and quality control may also be suitable for other testing purposes.

  10. 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.

  11. Proteomics analysis of latex from Hevea brasiliensis (clone RRIM 600).

    Science.gov (United States)

    Habib, Mohd Afiq Hazlami; Yuen, Gan Chee; Othman, Fazilah; Zainudin, Nurul Nabilah; Latiff, Aishah Abdul; Ismail, Mohd Nazri

    2017-04-01

    The natural rubber latex extracted from the bark of Hevea brasiliensis plays various important roles in today's modern society. Following ultracentrifugation, the latex can be separated into 3 layers: C-serum, lutoids, and rubber particles. Previous studies have shown that a large number of proteins are present in these 3 layers. However, a complete proteome for this important plant is still unavailable. Protein sequences have been recently translated from the completed draft genome database of H. brasiliensis, leading to the creation of annotated protein databases of the following H. brasiliensis biosynthetic pathways: photosynthesis, latex allergens, rubberwood formation, latex biosynthesis, and disease resistance. This research was conducted to identify the proteins contained within the latex by way of de novo sequencing from mass spectral data obtained from the 3 layers of the latex. Peptides from these proteins were fragmented using collision-induced dissociation, higher-energy collisional dissociation, and electron-transfer dissociation activation methods. A large percentage of proteins from the biosynthetic pathways (63% to 100%) were successfully identified. In addition, a total of 1839 unique proteins were identified from the whole translated draft genome database (AnnHBM).

  12. Euphorbia plant latex is inhabited by diverse microbial communities.

    Science.gov (United States)

    Gunawardana, Manjula; Hyde, Embriette R; Lahmeyer, Sean; Dorsey, Brian L; La Val, Taylor P; Mullen, Madeline; Yoo, Jennifer; Knight, Rob; Baum, Marc M

    2015-12-01

    The antimicrobial properties and toxicity of Euphorbia plant latex should make it a hostile environment to microbes. However, when specimens from Euphorbia spp. were propagated in tissue culture, microbial growth was observed routinely, raising the question whether the latex of this diverse plant genus can be a niche for polymicrobial communities. Latex from a phylogenetically diverse set of Euphorbia species was collected and genomic microbial DNA extracted. Deep sequencing of bar-coded amplicons from taxonomically informative gene fragments was used to measure bacterial and fungal species richness, evenness, and composition. Euphorbia latex was found to contain unexpectedly complex bacterial (mean: 44.0 species per sample; 9 plants analyzed) and fungal (mean: 20.9 species per sample; 22 plants analyzed) communities using culture-independent methods. Many of the identified taxa are known plant endophytes, but have not been previously found in latex. Our results suggest that Euphorbia plant latex, a putatively hostile antimicrobial environment, unexpectedly supports diverse bacterial and fungal communities. The ecological roles of these microorganisms and potential interactions with their host plants are unknown and warrant further research. © 2015 Botanical Society of America.

  13. 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.

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

    Science.gov (United States)

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

    2004-11-15

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

  15. Beaded streams of Arctic permafrost landscapes

    Science.gov (United States)

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

    2014-07-01

    Beaded streams are widespread in permafrost regions and are considered a common thermokarst landform. However, little is known about their distribution, how and under what conditions they form, and how their intriguing morphology translates to ecosystem functions and habitat. Here we report on a Circum-Arctic inventory of beaded streams and a watershed-scale analysis in northern Alaska using remote sensing and field studies. We mapped over 400 channel networks with beaded morphology throughout the continuous permafrost zone of northern Alaska, Canada, and Russia and found the highest abundance associated with medium- to high-ice content permafrost in moderately sloping terrain. In the Fish Creek watershed, beaded streams accounted for half of the drainage density, occurring primarily as low-order channels initiating from lakes and drained lake basins. Beaded streams predictably transition to alluvial channels with increasing drainage area and decreasing channel slope, although this transition is modified by local controls on water and sediment delivery. Comparison of one beaded channel using repeat photography between 1948 and 2013 indicate relatively stable form and 14C dating of basal sediments suggest channel formation may be as early as the Pleistocene-Holocene transition. Contemporary processes, such as deep snow accumulation in stream gulches effectively insulates river ice and allows for perennial liquid water below most beaded stream pools. Because of this, mean annual temperatures in pool beds are greater than 2 °C, leading to the development of perennial thaw bulbs or taliks underlying these thermokarst features. In the summer, some pools stratify thermally, which reduces permafrost thaw and maintains coldwater habitats. Snowmelt generated peak-flows decrease rapidly by two or more orders of magnitude to summer low flows with slow reach-scale velocity distributions ranging from 0.1 to 0.01 m s-1, yet channel runs still move water rapidly between pools

  16. Aerogel Beads as Cryogenic Thermal Insulation System

    Science.gov (United States)

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

    2001-01-01

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

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

    Science.gov (United States)

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

    2008-12-01

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

  18. Photoacoustic infrared spectroscopy of polymer beads.

    Science.gov (United States)

    Wen, Qing; Michaelian, Kirk H

    2009-09-01

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

  19. Detection of meningococcal antigen by latex agglutination.

    Science.gov (United States)

    Sobanski, M A; Barnes, R A; Coakley, W T

    2001-01-01

    Meningococcal meningitis and septicemia are serious infections with significant morbidity and mortality. A sensitive affordable test is required to provide evidence of meningococcal disease at the earliest opportunity to improve local management and give early warning of potential outbreaks of disease. Culture of organisms is considered the gold standard for diagnosis but is slow (24 h or more) and increasingly influenced by prior antibiotic treatment. Recently, the development of polymerase chain reaction (PCR) has improved diagnosis but this sensitive assay is costly, is not available at most primary care institutions and is not feasible for developing countries. Conventional latex agglutination (LA) enables rapid detection of bacterial antigen in cerebrospinal fluid (CSF) (1,2) and can also be used to test specimens of blood (3,4) or urine (5) and for serogroup determinations on primary cultures (6,7). We discuss here test-card agglutination and also describe a new technique based upon LA in an ultrasonic standing wave that retains the speed of direct antigen testing while significantly increasing sensitivity.

  20. Cooling Rates of Lunar Volcanic Glass Beads

    Science.gov (United States)

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

    2016-01-01

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

  1. Bead Capture on Magnetic Sensors in a Microfluidic System

    DEFF Research Database (Denmark)

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

    2009-01-01

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

  2. Bead and Process for Removing Dissolved Metal Contaminants

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-01-18

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

  3. Comparative transcriptome analysis of latex from rubber tree clone CATAS8-79 and PR107 reveals new cues for the regulation of latex regeneration and duration of latex flow.

    Science.gov (United States)

    Chao, Jinquan; Chen, Yueyi; Wu, Shaohua; Tian, Wei-Min

    2015-04-18

    Rubber tree (Hevea brasiliensis Muell. Arg.) is the primarily commercial source of natural rubber in the world. Latex regeneration and duration of latex flow after tapping are the two factors that determine rubber yield of rubber tree, and exhibit a huge variation between rubber tree clones CATAS8-79 and PR107. To dissect the molecular mechanism for the regulation of latex regeneration and duration of latex flow, we sequenced and comparatively analyzed latex of rubber tree clone CATAS8-79 and PR107 at transriptome level. More than 26 million clean reads were generated in each pool and 51,829 all-unigenes were totally assembled. A total of 6,726 unigenes with differential expression patterns were detected between CATAS8-79 and PR107. Functional analysis showed that genes related to mass of categories were differentially enriched between the two clones. Expression pattern of genes which were involved in latex regeneration and duration of latex flow upon successive tapping was analyzed by quantitative PCR. Several genes related to rubber biosynthesis, cellulose and lignin biosynthesis and rubber particle aggregation were differentially expressed between CATAS8-79 and PR107. This is the first report about probing latex regeneration and duration of latex flow by comparative transcriptome analysis. Among all the suggested factors, it is more important that the level of endogenous jasmonates, carbohydrate metabolism, hydroxymethylglutaryl-CoA reductase (HMGR) and Hevea rubber transferase (HRT) in mevalonate (MVA) parthway for latex regeneration while the level of endogenous ethylene (ETH), lignin content of laticifer cell wall, antioxidants and glucanases for the duration of latex flow. These data will provide new cues for understanding the molecular mechanism for the regulation of latex regeneration and duration of latex flow in rubber tree.

  4. Factors affecting the drying process of latex films

    Science.gov (United States)

    Carter, Farai T.

    During the past two decades, an improved understanding of the operative particle deformation mechanisms during latex film formation has been gained. For a particular colloidal dispersion with a known particle size, the Routh-Russel deformation maps predict the dominant mechanism for particle deformation for a particular set of conditions (evaporation rate, temperature, and initial film thickness). Although qualitative tests of the Routh-Russel model have been reported previously, a systematic study of the relationship between the film formation conditions and the resulting water concentration profiles is lacking. Here, the water distribution during the film formation of a series of acrylic copolymer latexes with varying glass transition temperature, Tg (values of -22, -11, 4 and 19 °C) has been obtained using GARField nuclear magnetic resonance profiling. A significant reduction in the rate of water loss from the latex with the lowest Tg was found, which is explained by its relatively low polymer viscosity enabling the growth of a coalesced skin layer. The transition between slowed drying and unimpeded drying occurs at the boundary between the capillary deformation and wet sintering regimes, in full agreement with the Routh-Russel model. An inverse correlation between the model¡¦s dimensionless control parameter and the dimensionless drying time is discovered, which is useful for the design of fast-drying waterborne films. The effect of particle size and bimodality on the film formation of latexes was also investigated. The differences in the drying rates at the early stages of drying due to different particle sizes were discovered. The latexes with unimodal smaller particle sizes were found to have longer characteristic drying times compared to those with unimodal larger particle sizes. This was postulated to be due to the Kelvin-Laplace theory of the reduction of vapour pressure of water due to the radius of the water menisci between polymer particles at the

  5. The antigenotoxic activity of latex from Himatanthus articulatus

    Directory of Open Access Journals (Sweden)

    Sebastião de O. Rebouças

    2011-11-01

    Full Text Available Himatanthus articulatus (Vahl Woodson (Apocynaceae is a native plant to the Amazon popularly used to treat ulcers, tumors, inflammations, cancer, syphilis and malaria. The aim of the present study was to investigate the in vivo genotoxic/antigenotoxic and mutagenic potential of this plant, using the comet and the micronucleus assays in mice. Female and male adult mice were treated with different doses of H. articulatus latex by gavage for two consecutive days. For the experiments, the latex was serially diluted with water to 1:2 (D1; 1:4 (D½ and 1:8 (D¼ and administered to the animals. The blood slides were exposed to hydrogen peroxide (ex vivo to evaluate antigenotoxic effect. Under the experimental conditions used in this study, the latex of H. articulatus did not increase the frequency of DNA damage as measured by the comet assay and micronucleus test in treated mice, indicating a non-genotoxic and non-mutagenic activity. In relation to the antigenotoxicity, latex exerted protective effect against DNA damage induced by hydrogen peroxide. Therefore, our results add new information about the antigenotoxic potential of H. articulatus latex, which is popularly used in the Amazon to treat different pathologies.

  6. Investigating the rheological properties of native plant latex.

    Science.gov (United States)

    Bauer, Georg; Friedrich, Christian; Gillig, Carina; Vollrath, Fritz; Speck, Thomas; Holland, Chris

    2014-01-06

    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 provides quantitative insights into the coagulation mechanisms of Euphorbia and Ficus latex allowing interpretation within a comparative evolutionary framework. Our findings reveal that in laboratory conditions both latices behave like non-Newtonian materials with the coagulation of Euphorbia latex being mediated by a slow evaporative process (more than 60 min), whereas Ficus appears to use additional biochemical components to increase the rate of coagulation (more than 30 min). Based on these results, we propose two different primary defensive roles for latex in these plants: the delivery of anti-herbivory compounds (Euphorbia) and rapid wound healing (Ficus).

  7. Caprine herpesvirus 1 (CpHV-1) vaginal infection of goats: clinical efficacy of fig latex.

    Science.gov (United States)

    Camero, Michele; Marinaro, Mariarosaria; Losurdo, Michele; Larocca, Vittorio; Bodnar, Livia; Patruno, Giovanni; Buonavoglia, Canio; Tempesta, Maria

    2016-01-01

    The latex of Ficus carica Linn. (Moraceae) has been shown to interfere with the replication of caprine herpesvirus (CpHV)-1 in vitro. The present study was undertaken to determine the efficacy of vaginal administration of fig latex in goats experimentally infected with CpHV-1. The fig latex reduced the clinical signs of the herpetic disease although it slightly influenced the titres of CpHV-1 shed. Thus, the fig latex maintained a partial efficacy in vivo.

  8. Gel bead composition for metal adsorption

    Science.gov (United States)

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

    1990-01-01

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

  9. Cutting Tool For Shaving Weld Beads

    Science.gov (United States)

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

    1995-01-01

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

  10. Fungal cultivation on glass-beads

    DEFF Research Database (Denmark)

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

    Transcription of various bioactive compounds and enzymes are dependent on fungal cultivation method. In this study we cultivate Fusarium graminearum and Fusarium solani on glass-beads with liquid media in petri dishes as an easy and inexpensive cultivation method, that resembles in secondary...... metabolite production to agar-cultivation but with an easier and more pure RNA-extraction of total fungal mycelia....

  11. bEADS Extended Actuated Digital Shaker

    DEFF Research Database (Denmark)

    Williams, Peter Leslie; Overholt, Daniel

    2017-01-01

    While there are a great variety of digital musical interfaces available to the working musician, few offer the level of immediate, nuanced and instinctive interaction that one finds in an acoustic shaker. bEADS is a prototype of a digital musical instrument that utilises the gestural vocabulary...

  12. 40 CFR 428.40 - Applicability; description of the latex rubber subcategory.

    Science.gov (United States)

    2010-07-01

    ... latex rubber subcategory. 428.40 Section 428.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS RUBBER MANUFACTURING POINT SOURCE CATEGORY Latex Rubber Subcategory § 428.40 Applicability; description of the latex rubber subcategory. The provisions of...

  13. 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¿

  14. Morphology and film formation of poly(butyl methacrylate)-polypyrrole core-shell latex particles

    NARCIS (Netherlands)

    Huijs, F; Lang, J

    Core-shell latex particles made of a poly(butyl methacrylate) (PBMA) core and a thin polypyrrole (PPy) shell were synthesized by two-stage polymerization. In the first stage, PBMA latex particles were synthesized in a semicontinuous process by free-radical polymerization. PBMA latex particles were

  15. Science and technology of rubber reclamation with special attention to NR based waste latex products

    NARCIS (Netherlands)

    Rajan, V.V.; Dierkes, Wilma K.; Joseph, R.; Noordermeer, Jacobus W.M.

    2006-01-01

    A comprehensive overview of reclamation of cured rubber with special emphasis on latex reclamation is depicted in this paper. The latex industry has expanded over the years to meet the world demands for gloves, condoms, latex thread, etc. Due to the strict specifications for the products and the

  16. Evaluation of hemostatic activity of latex from three Euphorbiaceae species.

    Science.gov (United States)

    Badgujar, Shamkant B

    2014-01-01

    Latices from several plant species of Euphorbiaceae family have been traditionally applied over fresh cuts to stop bleeding and subsequently applied over wounds to enhance healing process. The latex arrested bleeding from fresh wounds by reducing bleeding and whole blood coagulation time which are important indices of hemostatic activity. It has been accepted that hemostatic activity is due to the proteolytic fraction of plant latices. Thus, the present study aimed to assess the clot inducing properties of three Euphorbiaceae plants viz., Euphorbia nivulia Buch.-Ham., Pedilanthus tithymaloides (L.) Poit and Synadenium grantii Hook F. In the present study, various proteolytic activities namely protease, gelatinase, milk clotting and whole blood clotting assay of the enzyme fraction of latices of Euphorbia nivulia, Pedilanthus tithymaloides and Synadenium grantii have been investigated. The inhibition profile of protease specific inhibitors was assessed. Also, the effects of protein fractions were studied using bleeding/clotting time test of fresh experimentally-induced wounds in mice. Euphorbia nivulia latex protease has noticeable blood clotting activity followed by Pedilanthus tithymaloides and Synadenium grantii. Stem latex protease of Pedilanthus tithymaloides exhibits superior procoagulant activity in different mammal's blood samples viz., Capra hircus, Bubalus bubalis, Ovibos moschatus and Bos indicus. Blood sample of ox was the most sensitive to latex protease than other mammal's blood. Concomitantly, the plant latex protease could significantly reduce whole blood clotting time of human and mice blood samples. The protease fraction of latices of Euphorbia nivulia, Pedilanthus tithymaloides and Synadenium grantii possesses phytoconstituents capable of arresting wound bleeding, and accelerating whole blood coagulation process. It suggests good potentiality for use of latex proteases in wound management. Also, the finding of this study showed that the protease

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

    Science.gov (United States)

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

    2011-10-01

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

  18. A Controlled Drug-Delivery Experiment Using Alginate Beads

    Science.gov (United States)

    Farrell, Stephanie; Vernengo, Jennifer

    2012-01-01

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

  19. Compressive and Tensile Strength of Expanded Polystyrene Beads Concrete

    OpenAIRE

    Subhan, Tengku Fitriani L

    2005-01-01

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

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

    Science.gov (United States)

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

    2010-01-01

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

  1. Human fibrinogen adsorption on positively charged latex particles.

    Science.gov (United States)

    Zeliszewska, Paulina; Bratek-Skicki, Anna; Adamczyk, Zbigniew; Cieśla, Michał

    2014-09-23

    Fibrinogen (Fb) adsorption on positively charged latex particles (average diameter of 800 nm) was studied using the microelectrophoretic and the concentration depletion methods based on AFM imaging. Monolayers on latex were adsorbed from diluted bulk solutions at pH 7.4 and an ionic strength in the range of 10(-3) to 0.15 M where fibrinogen molecules exhibited an average negative charge. The electrophoretic mobility of the latex after controlled fibrinogen adsorption was systematically measured. A monotonic decrease in the electrophoretic mobility of fibrinogen-covered latex was observed for all ionic strengths. The results of these experiments were interpreted according to the three-dimensional electrokinetic model. It was also determined using the concentration depletion method that fibrinogen adsorption was irreversible and the maximum coverage was equal to 0.6 mg m(-2) for ionic strength 10(-3) M and 1.3 mg m(-2) for ionic strength 0.15 M. The increase of the maximum coverage was confirmed by theoretical modeling based on the random sequential adsorption approach. Paradoxically, the maximum coverage of fibrinogen on positively charged latex particles was more than two times lower than the maximum coverage obtained for negative latex particles (3.2 mg m(-2)) at pH 7.4 and ionic strength of 0.15 M. This was interpreted as a result of the side-on adsorption of fibrinogen molecules with their negatively charged core attached to the positively charged latex surface. The stability and acid base properties of fibrinogen monolayers on latex were also determined in pH cycling experiments where it was observed that there were no irreversible conformational changes in the fibrinogen monolayers. Additionally, the zeta potential of monolayers was more positive than the zeta potential of fibrinogen in the bulk, which proves a heterogeneous charge distribution. These experimental data reveal a new, side-on adsorption mechanism of fibrinogen on positively charged surfaces and

  2. Peptidases and peptidase inhibitors in gut of caterpillars and in the latex of their host plants.

    Science.gov (United States)

    Ramos, Márcio V; Pereira, Danielle A; Souza, Diego P; Silva, Maria-Lídia S; Alencar, Luciana M R; Sousa, Jeanlex S; Queiroz, Juliany-Fátima N; Freitas, Cleverson D T

    2015-01-01

    Studies investigating the resistance-susceptibility of crop insects to proteins found in latex fluids have been reported. However, latex-bearing plants also host insects. In this study, the gut proteolytic system of Pseudosphinx tetrio, which feeds on Plumeria rubra leaves, was characterized and further challenged against the latex proteolytic system of its own host plant and those of other latex-bearing plants. The gut proteolytic system of Danaus plexippus (monarch) and the latex proteolytic system of its host plant (Calotropis procera) were also studied. The latex proteins underwent extensive hydrolysis when mixed with the corresponding gut homogenates of the hosted insects. The gut homogenates partially digested the latex proteins of foreign plants. The fifth instar of D. plexippus that were fed diets containing foreign latex developed as well as those individuals who were fed diets containing latex proteins from their host plant. In vitro assays detected serine and cysteine peptidase inhibitors in both the gut homogenates and the latex fluids. Curiously, the peptidase inhibitors of caterpillars did not inhibit the latex peptidases of their host plants. However, the peptidase inhibitors of laticifer origin inhibited the proteolysis of gut homogenates. In vivo analyses of the peritrophic membrane proteins of D. plexippus demonstrate resistance against latex peptidases. Only discrete changes were observed when the peritrophic membrane was directly treated with purified latex peptidases in vitro. This study concludes that peptidase inhibitors are involved in the defensive systems of both caterpillars and their host plants. Although latex peptidase inhibitors inhibit gut peptidases (in vitro), the ability of gut peptidases to digest latex proteins (in vivo) regardless of their origin seems to be important in governing the resistance-susceptibility of caterpillars.

  3. A model for magnetic bead microrheometry

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-04-15

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

  4. Defense-related Proteins from Chelidonium majus L. as Important Components of its Latex.

    Science.gov (United States)

    Nawrot, Robert

    2017-01-01

    The aim of this review is to cover most recent research on plant pathogenesis- and defenserelated proteins from latex-bearing medicinal plant Chelidonium majus (Papaveraceae) in the context of its importance for latex activity, function, pharmacological activities, and antiviral medicinal use. These results are compared with other latex-bearing plant species and recent research on proteins and chemical compounds contained in their latex. This is the first review, which clearly summarizes pathogenesisrelated (PR) protein families in latex-bearing plants pointing into their possible functions. The possible antiviral function of the latex by naming the abundant proteins present therein is also emphasized. Finally latex-borne defense system is hypothesized to constitute a novel type of preformed immediate defense response against viral, but also non-viral pathogens, and herbivores. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  5. LaTeX - Know what you are missing

    Directory of Open Access Journals (Sweden)

    Gunther Maier

    2016-11-01

    Full Text Available This article gives a brief introduction to \\LaTeX\\ and related tools. The aim is to give an overview, to demonstrate the flexibility and versatility of the software, and to assist the reader taking first steps using it. The article links to a number of valuable resources for further information.

  6. How To Refinish Wood Siding With Latex Paints

    Science.gov (United States)

    E. A. Mraz

    1976-01-01

    Every homeowner with painted wood siding and trim at some time faces the job of repainting. In this note a simple test is described to determine whether an old surface will form a satisfactory bond with latex paints, and suggestions are given on preparing the surface to achieve a satisfactory bond.

  7. Latex allergy at Groote Schuur hospital prevalence, clinical features ...

    African Journals Online (AJOL)

    Workers who were symptomatic had Immunocap RAST (CAP RAST) or skin-prick tests to confirm latex sensitivity. Latexavoidance measures were implemented in positive subjects. One hundred symptomatic, sensitised individuals were followed up 3 months after intervention to assess their clinical status. A further cohort of ...

  8. 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.

  9. A Protease Isolated from the Latex of Plumeria rubra Linn ...

    African Journals Online (AJOL)

    Methods: The protease was isolated from the latex of the plant by acetone precipitation method and given a trivial name, Plumerin-R. The anti-inflammatory activity of the protease was based on its effects on carrageenan-induced paw oedema in rats. Its wound healing effect was investigated using an excision wound rat ...

  10. In vitro antifungal activity of Argemone ochroleuca Sweet latex ...

    African Journals Online (AJOL)

    mahmoud

    2013-02-22

    Feb 22, 2013 ... cancer (Ducray et al., 2011), antiparasitic (Martínez et al.,. 2010) and antiprotozoa ... Morelos, México against four fungal postharvest pathogens of fruits ... from the latex of Hevea brasiliensis on oral microorganisms. Mycoses ...

  11. Incidence of latex harvesting technologies on agronomic and ...

    African Journals Online (AJOL)

    High tapping frequency does not therefore have a negative effect on thiol group content, but rather results in high concentrations linked to a higher metabolic activity (Jacob et al.,. 1995). This result shows and confirms that tapping increases the metabolic energy of the tree. Incidence of latex harvesting technologies.

  12. 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

  13. Systemes De Recolte Du Latex Adaptes A La Saignee Descendante ...

    African Journals Online (AJOL)

    However systems applied up to now were to harvest the latex of this clone didn't allowed eradicating its sensitivity to tapping panel dryness and fragility. An experiment was led in south east of Côte d'Ivoire in order to determine a high performance harvesting technique of this clone in downward tapping. The clone PB 235 ...

  14. Incidence of latex harvesting technologies on agronomic and ...

    African Journals Online (AJOL)

    field of plant and latex physiology (Jacob et al., 1988; Lacrotte, 1991; Gohet, 1996). These works helped group clones into three metabolic activity classes' slow, moderate and rapid (Serres et al., 1994; Jacob et al., 1995;. Gohet et al., 1996). Rapid metabolic activity class includes clones with an easy flow leading to high ...

  15. Latex allergy: 'Plight, rights and fights' | Potter | South African ...

    African Journals Online (AJOL)

    South African Medical Journal. Journal Home · ABOUT · Advanced Search · Current Issue · Archives · Journal Home > Vol 103, No 6 (2013) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register. Latex allergy: 'Plight, rights and fights'. PC Potter. Abstract. No Abstract.

  16. Plant latex lipase as biocatalysts for biodiesel production

    African Journals Online (AJOL)

    MAZOU Mouaïmine

    2016-07-13

    Jul 13, 2016 ... extensively studied, little research has been focused on the use of plant lipases namely plant latex lipases. The present .... When the fruit is green, it .... high pH levels. Optimum conditions for assaying CPL activity on olive oil were therefore set at pH 9. No significant activity could be detected at pH 6 or less.

  17. Oil-acrylic hybrid latexes as binders for waterborne coatings

    NARCIS (Netherlands)

    Hamersveld, van E.M.S.; Es, van J.; German, A.L.; Cuperus, F.P.; Weissenborn, P.; Hellgren, A.C.

    1999-01-01

    The combination of the characteristics of oil, or alkyd, emulsions and acrylic latexes in a waterborne binder has been the object of various studies in the past. Strategies for combining the positive properties of alkyds, e.g. autoxidative curing, gloss and penetration in wood, with the fast drying

  18. Page 1 CHEMICAL EXAMINATION OF JACK TREE LATEX AND ...

    Indian Academy of Sciences (India)

    green stem is cut or when a twig or leaf is broken off. During the war there was great interest in the study of plant latices and we had occasion to examine a small quantity of the Jack tree latex. It was coagulated by adding just enough of alcohol (equal volume) and the resulting coagulum. (A) and aqueous alcoholic mother ...

  19. Marine bacterial prodigiosin as dye for rubber latex, polymethyl ...

    African Journals Online (AJOL)

    Prodigiosin is known for its immunomodulatory, antibacterial, antimycotic, antimalarial, algicidal and anticancer activities. Here, we reported the evaluation of prodigiosin pigment as a dyeing agent in rubber latex, paper and polymethyl methacrylate (PMMA) so that it can be considered as an alternative to synthetic pigments.

  20. Phosphorus removal from aquaculture wastewater and latex by ...

    African Journals Online (AJOL)

    The treatments included raw municipal wastewater (RMW), treated municipal wastewater (TMW), and diluted fresh latex (DFL). The experiment was performed in the open air of Khorasgan University area for 18 days “without aeration” and 18 days “with aeration” after the period of “without aeration”. The results of the study ...

  1. A Latex Agglutination Test for Capripoxvirus | Muinamia | Journal of ...

    African Journals Online (AJOL)

    disease, by a latex agglutination test (LAT) using the purified P32 antigen and guinea pig detector antiserum raised against the P32 antigen. The LAT and virus neutralization test (VNT) were used to screen one hundred livestock field sera for antibodies to Capripoxvirus, in comparison the LAT was simpler, rapid and 23% ...

  2. Metabolic routes affecting rubber biosynthesis in Hevea brasiliensis latex

    Science.gov (United States)

    Chow, Keng-See; Mat-Isa, Mohd.-Noor; Bahari, Azlina; Ghazali, Ahmad-Kamal; Alias, Halimah; Mohd.-Zainuddin, Zainorlina; Hoh, Chee-Choong; Wan, Kiew-Lian

    2012-01-01

    The cytosolic mevalonate (MVA) pathway in Hevea brasiliensis latex is the conventionally accepted pathway which provides isopentenyl diphosphate (IPP) for cis-polyisoprene (rubber) biosynthesis. However, the plastidic 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway may be an alternative source of IPP since its more recent discovery in plants. Quantitative RT-PCR (qRT-PCR) expression profiles of genes from both pathways in latex showed that subcellular compartmentalization of IPP for cis-polyisoprene synthesis is related to the degree of plastidic carotenoid synthesis. From this, the occurrence of two schemes of IPP partitioning and utilization within one species is proposed whereby the supply of IPP for cis-polyisoprene from the MEP pathway is related to carotenoid production in latex. Subsequently, a set of latex unique gene transcripts was sequenced and assembled and they were then mapped to IPP-requiring pathways. Up to eight such pathways, including cis-polyisoprene biosynthesis, were identified. Our findings on pre- and post-IPP metabolic routes form an important aspect of a pathway knowledge-driven approach to enhancing cis-polyisoprene biosynthesis in transgenic rubber trees. PMID:22162870

  3. Implication of Climate Variability for Latex Exudates F Rubber Tree ...

    African Journals Online (AJOL)

    The study aimed at: assessing the relationship between latex exudates and climate variability; identifying the most critical climate element(s) in the yield variability of rubber; and examining the predictability of rubber yield based on climate variability. Fifteen years data was collected from documented, but unpublished, ...

  4. In vitro antifungal activity of Argemone ochroleuca Sweet latex ...

    African Journals Online (AJOL)

    The in vitro antifungal activities of crude latex of Argemone ochroleuca Sweet against four clinical isolates of Candida (Candida albicans, Candida glabrata, Candida krusei and Candida tropicalis) and six isolates of plant pathogenic fungi (Alternaria alternate, Drechslera halodes, Fusarium oxysporum, Macrophomina ...

  5. Evaluation of the sensitivity and specificity of latex agglutination and ...

    African Journals Online (AJOL)

    The sensitivity and specificity of latex agglutination test (LAT) and Complement fixation test (CFT) for the field diagnosis of Contagious Bovine Pleuropneumonia were determined using 90 bovine sera from various parts of the country. Of the ninety samples tested, 17 (18.9%) were positive in both tests, 2 (2.2%) were ...

  6. Statistical discrimination of latex between healthy and white root ...

    African Journals Online (AJOL)

    White root disease is a critical factor of infection to rubber trees in Malaysia. Therefore, research represent the identification of healthy and infected rubber trees is very significant in order to maintain the yield of rubber tree latex. A total of 60 samples from healthy and white root disease (WRD) infected rubber tree respectively ...

  7. SUBSTRATE EFFECTS ON VOC EMISSIONS FROM A LATEX PAINT

    Science.gov (United States)

    The effects of two substrates -- a stainless steel plate and a gypsum board -- on the volatile organic compound (VOC) emissions from a latex paint were evaluated by environmental chamber tests. It was found that the amount of VOCs emitted from the painted stainless steel was 2 to...

  8. Cutting height effects on guayule latex, rubber and resin yields

    Science.gov (United States)

    Guayule (Parthenium argentatum Gray) is a perennial shrub native to the Chihuahuan Desert. While guayule traditionally has been cultivated for rubber, more recently it is being cultivated for its hypoallergenic latex. Other uses including termite resistant wood products and as an energy source have ...

  9. 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

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

    Science.gov (United States)

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

    2017-01-01

    This paper presents a deterministic bead-in-droplet ejection (BIDE) technique that regulates the precise distribution of microbeads in an ejected droplet. The deterministic BIDE was realized through the effective integration of a microfluidic single-particle handling technique with a liquid dispensing system. The integrated bead dispenser facilitates the transfer of the desired number of beads into a dispensing volume and the on-demand ejection of bead-encapsulated droplets. Single bead–encapsulated droplets were ejected every 3 s without any failure. Multiple-bead dispensing with deterministic control of the number of beads was demonstrated to emphasize the originality and quality of the proposed dispensing technique. The dispenser was mounted using a plug-socket type connection, and the dispensing process was completely automated using a programmed sequence without any microscopic observation. To demonstrate a potential application of the technique, bead-based streptavidin–biotin binding assay in an evaporating droplet was conducted using ultralow numbers of beads. The results evidenced the number of beads in the droplet crucially influences the reliability of the assay. Therefore, the proposed deterministic bead-in-droplet technology can be utilized to deliver desired beads onto a reaction site, particularly to reliably and efficiently enrich and detect target biomolecules. PMID:28393911

  11. 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

  12. [Contact allergy to latex in health care workers--study of case reports].

    Science.gov (United States)

    Krecisz, Beata; Kieć-Swierczyńska, Marta

    2004-01-01

    Contact allergy to latex is a relatively new problem that gives rise to much controversy among researchers. The aim of the study was to develop a study model of contact allergy induced by latex proteins. The study covered 60 health care workers who had reported decreased tolerance of rubber gloves. They were subjected to routine dermatological examinations, patch tests to a standard set of allergens (Chemotechnique Diagnosis, Sweden), expanded to include high ammoniac latex, and prick tests with latex and common inhalatory allergens. In addition, total and latex specific IgE antibodies were determined. Of the total group, contact allergy to latex was found in 5 persons, including 3 persons with concurrent immediate reaction to latex, and 2 persons with allergy of the isolated nature. Only in 1 person coexistent late allergy to latex and rubber accelerator of the thiurams group were observed. Path tests with 30% ammoniac latex seem to be a useful diagnostic method in the detection of contact allergy to latex. In case of doubtful reactions, the use of lower allergen concentrations is recommended.

  13. Prenatal latex sensitization in patients with spina bifida: a pilot study.

    Science.gov (United States)

    Boettcher, Michael; Goettler, Susanne; Eschenburg, Georg; Kracht, Thorben; Kunkel, Philip; Von der Wense, Axel; Reinshagen, Konrad

    2014-03-01

    Patients with spina bifida are particularly vulnerable to developing immunoglobulin E (IgE)-mediated latex sensitization. Even though many risk factors leading to latex allergy in these patients have been described, it is still unclear whether the increased prevalence of latex sensitization is disease associated or due to the procedures used to treat spina bifida. The aim of this study was to assess prenatal latex sensitization in patients with spina bifida by examining IgE levels in umbilical cord blood. Patients with spina bifida and matched healthy infants were recruited from the University Medical Center Hamburg-Eppendorf and Children's Hospital Altona. Latex-specific and total IgE were assessed in umbilical cord blood using ImmunoCAP testing to evaluate the degree of prenatal latex sensitization. Twenty-two subjects, 10 with spina bifida and 12 healthy individuals, were included. Subjects were selected after matching for sex, gestational age, weight, parental allergy profile, number of prenatal examinations, and utilization of latex tools during pregnancy (propensity score estimates, p = 0.36). In patients with spina bifida, latex-specific and total IgE levels were significantly higher than those in healthy individuals (p = 0.001). After normalization to total IgE, latex-specific IgE levels were higher, yet not significantly increased (p = 0.085). Perinatally, there is a significant augmentation of total and latex-specific IgE in patients with spina bifida. After correcting for total IgE, latex-specific IgE was increased, yet not significantly higher than in matched, healthy controls. This pilot study gives novel insights in the immunological reactions related to spina bifida. The increased latex-specific IgE levels could possibly be associated with the occurrence of a latex allergy in the future.

  14. Transparent, conductive coatings from latex-based dispersions

    Science.gov (United States)

    Sun, Jiakuan

    Flexible, transparent and conductive coatings were prepared using polymeric latex as the matrix starting material, and transparent and conductive nanoparticles as the conductive filler. A stable aqueous dispersion of latex and conductive nanoparticles was prepared and deposited onto polymer substrates. Upon drying above the glass transition temperature of polymer, latex particles consolidated, compacted, deformed, and eventually coalesced, forcing the conductive nanoparticles into the boundary regions between latex and thereby resulting in a segregated microstructure. This segregated microstructure enables electrical conduction at relatively low filler concentration and optical transparency as well. The conductivity of the composite coatings is described by percolation theory. The colloidal stability of the starting aqueous dispersions affects the coating microstructures and properties. A stable dispersion with the separated colloidal state dominated by electrostatic repulsion is desired for a good combination of conductivity and transparency. The electrical properties of the composite coatings are affected by the physical morphology of latices and conductive fillers, the intrinsic resistivity of conductive fillers, and the interaction between matrix and filler. The transparency is affected by the distribution of conductive fillers in matrix and the refractive index difference between matrix and filler. As latex particle size increases, the conductivity percolation occurs at lower filler contents. As the intrinsic resistivity of filler decreases, the conductivity of the resulting composite coatings past the percolation threshold increases. So far, poly(3,4-ethylenedioxythiothene)/poly(4-styrenesufonate) PEDOT/PSS gel particles appear to be the best conductive filler due to their special morphology (water-swelled polymeric gel particles), high intrinsic conductivity (after polar solvent modification), and nearly matching refractive index with matrix polymer. The

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

    Science.gov (United States)

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

    2013-09-01

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

  16. HPMA and HEMA copolymer bead interactions with eukaryotic cells

    Directory of Open Access Journals (Sweden)

    Cristina D. Vianna-Soares

    2004-09-01

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

  17. A latex agglutination assay to quantify the amount of hemagglutinin protein in adjuvanted low-dose influenza monovalent vaccines.

    Science.gov (United States)

    Buffin, Sophie; Ikhelef, Nabila; Prudent, Julien; Dubayle, Joseline; Nougarede, Nolwenn; Varenne, Marie-Pierre; Moste, Catherine; Legastelois, Isabelle

    2018-01-01

    To formulate inactivated influenza vaccines, the concentration of hemagglutinin (HA) must be accurately determined. The standard test currently used to measure HA in influenza vaccines is the Single Radial Immunodiffusion (SRID) assay. We developed a very rapid, simple and sensitive alternative quantitative HA assay, namely the Latex Agglutination Assay (LAA). The LAA uses the Spherotest® technology, which is based on the agglutination of HA-specific immunoglobulin-coated latex beads. The amount of HA in a sample is calculated from the level of bead agglutination by a simple absorbance measurement at 405nm against a standard curve generated using a monovalent vaccine standard. In less than 2hours, tens of samples could be quantified using the LAA as opposed to 2days for the SRID assay. Ten steps are required to complete an SRID assay as compared to 6 steps for the LAA, from sample preparation through spectrophotometric analysis. Furthermore, the limit of detection of the LAA was found to be approximately 15ng HA/mL, similar to an ELISA, with the quantification of less than 1.8μg HA/mL. The quantification limit of the SRID is usually considered to be approximately 5μg HA/mL. The development of the assay and a comparison of the titers obtained by SRID and LAA for several monovalent vaccines corresponding to various strains were performed. For A/H5N1 and A/H1N1 monovalent vaccines, the LAA was found to be linear and accurate as compared to the SRID. The precision of the LAA was close to that of the standard test, and good reproducibility from one laboratory to another was observed. Moreover, the LAA enabled HA quantification in AlOOH-adjuvanted and in emulsion-adjuvanted low-dose vaccines as well as unadjuvanted vaccines. In conclusion, LAA may be useful to rapidly and accurately measure influenza HA protein in monovalent vaccines, especially in those containing less than 5μg/mL of HA in the presence of an adjuvant. Copyright © 2017 The Authors. Published by

  18. Phase Diagram Characterization Using Magnetic Beads as Liquid Carriers

    OpenAIRE

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

    2015-01-01

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

  19. 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)

  20. Synthesis of PMMA/Polysiloxane Core-Shell Latex

    Directory of Open Access Journals (Sweden)

    Yu Chengbing

    2015-01-01

    Full Text Available In this study, silicon-acrylic latex, consisting of poly (methyl methacrylate (PMMA as the core and modified polysiloxane as the shell, had been successfully synthesized via cationic emulsion polymerization. The structure of the silicon-acrylic latex was confirmed by means of DLS, FTIR and TGA. There was an increase of 24.74 nm in average particle size and a shift of the size distribution to large sizes for core-shell particles in comparison with the original PMMA core particles, which indicated the formation of core-shell structure. The typical absorption peaks of Si-O-Si and Si-O-C in infrared spectrum indicated that the hydroxyl groups on the PMMA surface had reacted with the silanol groups, which could be confirmed by heterogeneous two-component system form TGA test.

  1. Ocular toxicity by latex of Calotropis procera (Sodom apple).

    Science.gov (United States)

    Basak, Samar K; 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%) had iridocyclitis, and seven (24%) had associated secondary glaucoma. After treatment with topical corticosteroids, antiglaucoma agents, cycloplegics, hypertonic saline and tears supplements, 27 (93%) eyes recovered completely within 3-14 days. After three months, 17 (74%) out of 23 eyes showed a significant low endothelial cell count compared to the normal fellow eye ( P 0.001). The latex of Calotropis procera causes significant ocular morbidity which may be preventable by simple health education. The long-term effect on corneal endothelium has to be studied further.

  2. Adsorption of CO2 by alginate immobilized zeolite beads

    Science.gov (United States)

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

    2017-03-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-12-01

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

  4. Creating nanoshell on the surface of titanium hydride bead

    Directory of Open Access Journals (Sweden)

    PAVLENKO Vyacheslav Ivanovich

    2016-12-01

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

  5. Ormosil Beads for Insulation of Ground Cryogenic Storage Tanks Project

    Data.gov (United States)

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

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

    Science.gov (United States)

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

    2016-02-01

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

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

    CERN Document Server

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

    2014-01-01

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

  8. Enzymatic activities and protein profile of latex from Calotropis procera.

    Science.gov (United States)

    Freitas, Cleverson Diniz T; Oliveira, Jefferson Soares; Miranda, Maria Raquel A; Macedo, Nívea Maria R; Sales, Maurício Pereira; Villas-Boas, Laurival A; Ramos, Márcio Viana

    2007-01-01

    The laticifer fluid of Calotropis procera is rich in proteins and there is evidence that they are involved in the pharmacological properties of the latex. However, not much is known about how the latex-containing proteins are produced or their functions. In this study, laticifer proteins of C. procera were pooled and examined by 1D and 2D electrophoresis, masses spectrometry (MALDI-TOF) and characterized in respect of proteolytic activity and oxidative enzymes. Soluble laticifer proteins were predominantly composed of basic proteins (PI>6.0) with molecular masses varying between 5 and 95 kDa. Proteins with a molecular mass of approximately 26,000 Da were more evident. Strong anti-oxidative activity of superoxide dismutase (EC 1.15.1.1) (1007.74+/-91.89 Ug(-1)DM) and, to a lesser extent ascorbate peroxidase (EC 1.11.1.1) (0.117(d)+/-0.013 microMol H(2)O(2)g(-1)min(-1)), were detected. However, catalase (EC 1.11.1.6) was absent. The strong proteolytic activities of laticifer proteins from C. procera were shown to be shared by at least four distinct cysteine proteinases (EC 3.4.22.16) that were isolated by gel filtration chromatography. Serine and metaloproteinases were not detected and aspartic proteinase activities were barely visible. Chitinases (EC 3.2.1.14) were also isolated in a chitin column and their activities quantified. The presence of these enzymatic activities in latex from C. procera may confirm their involvement in resistance to phytopathogens and insects, mainly in its leaves where the latex circulates abundantly.

  9. 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%.

  10. Progress in radiation vulcanization of natural rubber latex

    Energy Technology Data Exchange (ETDEWEB)

    Makuuchi, Keizo [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2000-03-01

    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)

  11. Cytotoxic cardenolides from the latex of Calotropis procera.

    Science.gov (United States)

    Mohamed, Nadia H; Liu, Miaomiao; Abdel-Mageed, Wael M; Alwahibi, Lamya H; Dai, Huanqin; Ismail, Mady Ahmed; Badr, Gamal; Quinn, Ronald J; Liu, Xueting; Zhang, Lixin; Shoreit, Ahmed A M

    2015-10-15

    Three new cardenolides (3, 9 and 10), along with eight known ones, were isolated from the latex of Calotropis procera. The structural determination was accomplished by the 1D- and 2D-NMR spectra as well as HRESIMS analysis. The growth inhibitory activity of the latex and its sub-fractions as well as isolated compounds was evaluated against human A549 and Hela cell lines. The results exhibited that latex had strong growth inhibitory activity with IC50s of (3.37 μM, A-549) and (6.45 μM, Hela). Among the four extracts (hexane, chloroform, ethyl acetate and aqueous), chloroform extract displayed the highest potential cytotoxic activity, with IC50s of (0.985 μM, A-549) and (1.471 μM, Hela). All the isolated compounds displayed various degrees of cytotoxic activity and the highest activity was observed by calactin (1) with IC50s values of (0.036 μM, A-549) and (0.083 μM, Hela). None of these isolated compounds exhibited good antimicrobial activity evaluated by determination of their MICs using the broth microdilution method against various infectious pathogens. The structure-activity relationships for cytotoxic activity were also discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Therapeutic effects of fig tree latex on bovine papillomatosis.

    Science.gov (United States)

    Hemmatzadeh, F; Fatemi, A; Amini, F

    2003-12-01

    The effects of fig tree latex in treating teat papillomatosis in cow in comparison with salicylic acid were evaluated. For this purpose, 12 cows of 1-3 years of age (average 2.25) affected by teat papillomatosis were divided into three groups. In group A, four cows were treated by fig tree (Ficus carica) latex; in group B, four cows were treated with 10% salicylic acid solution and in group C, four cows were kept as control animals receiving no treatment. Animals in each treatment group received their treatment once every 5 days. In groups A and B, de-epithelialization and shrinking of the warts began from the fifth day of treatment and all the warts disappeared within 30 days. However, in the control group no changes in the number of warts were observed until day 15 but thereafter a number of warts disappeared spontaneously in some of the animals. Both salicylic acid and fig tree latex were evaluated as having similar therapeutic effects in treating teat papillomatosis in cow.

  13. Extractable proteins from field radiation vulcanized natural rubber latex

    Energy Technology Data Exchange (ETDEWEB)

    Parra, Duclerc F. [Chemical and Environmental Centre, Nuclear Energy Research Institute, Av. Lineu Prestes, 2242-CEP Sao Paulo (Brazil)]. E-mail: dfparra@ipen.br; Pinto Martins, Carlos Felipe [Chemical and Environmental Centre, Nuclear Energy Research Institute, Av. Lineu Prestes, 2242-CEP Sao Paulo (Brazil); Collantes, Hugo D.C. [Chemical and Environmental Centre, Nuclear Energy Research Institute, Av. Lineu Prestes, 2242-CEP Sao Paulo (Brazil); Lugao, Ademar B. [Chemical and Environmental Centre, Nuclear Energy Research Institute, Av. Lineu Prestes, 2242-CEP Sao Paulo (Brazil)

    2005-07-01

    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 {sup 60}Co 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.

  14. Chitinase III in Euphorbia characias latex: Purification and characterization.

    Science.gov (United States)

    Spanò, Delia; Pospiskova, Kristyna; Safarik, Ivo; Pisano, Maria Barbara; Pintus, Francesca; Floris, Giovanni; Medda, Rosaria

    2015-12-01

    This paper deals with the purification of a class III endochitinase from Euphorbia characias latex. Described purification method includes an effective novel separation step using magnetic chitin particles. Application of magnetic affinity adsorbent noticeably simplifies and shortens the purification procedure. This step and the subsequently DEAE-cellulose chromatography enable to obtain the chitinase in homogeneous form. One protein band is present on PAGE in non-denaturing conditions and SDS-PAGE profile reveals a unique protein band of 36.5 ± 2 kDa. The optimal chitinase activity is observed at 50 °C, pH 5.0. E. characias latex chitinase is able to hydrolyze colloidal chitin giving, as reaction products, N-acetyl-D-glucosamine, chitobiose and chitotriose. Moreover, we observed that calcium and magnesium ions enhance chitinase activity. Finally, we cloned the cDNA encoding the E. characias latex chitinase. The partial cDNA nucleotide sequence contains 762 bp, and the deduced amino acid sequence (254 amino acids) is homologous to the sequence of several plant class III endochitinases. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Differentiating of cross-reactions in patients with latex allergy with the use of ISAC test.

    Science.gov (United States)

    Chełmińska, Marta; Specjalski, Krzysztof; Różyło, Anna; Kołakowska, Agata; Jassem, Ewa

    2016-04-01

    Differentiating between cross-reactivity and double sensitization is still a challenging issue in allergology. To differentiate cross-reactions accompanying latex allergy with the use of the ISAC test. Thirty-nine patients reporting immediate allergic reactions to latex were enrolled into the study (group A). The control group was comprised of 41 patients with allergic diseases not associated with latex (group B) and 20 healthy individuals (group C). Their history was recorded and skin prick tests were performed with latex, airborne and food allergens. Specific IgE against food allergens, latex (k82) and recombined latex allergens were determined. ImmunoCAP ISAC test was performed with 103 molecules. Sensitization to latex was found by means of skin tests in 16 cases and sIgE against latex was revealed in 12 cases (including 10 positive in both SPT and sIgE). In the ISAC test antibodies against recombined latex allergens were found in 8 patients with rHev b 6 as the most common. All the patients positive for rHev b 1, 5, 6, 8 had allergy or asymptomatic sensitization to food allergens cross-reacting with latex. Some reactions could not have been differentiated due to the lack of allergens in the ISAC test. Others, not related to latex-fruits syndrome were explained by cross-reactivity with other profilins or PR-10 proteins. ImmunoCAP ISAC test could be useful in differentiating between cross-reactions and double sensitizations. However, in the case of latex its advantages are limited due to a small panel of allergens.

  16. 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.

  17. Comprehensive Proteomics Analysis of Laticifer Latex Reveals New Insights into Ethylene Stimulation of Natural Rubber Production.

    Science.gov (United States)

    Wang, Xuchu; Wang, Dan; Sun, Yong; Yang, Qian; Chang, Lili; Wang, Limin; Meng, Xueru; Huang, Qixing; Jin, Xiang; Tong, Zheng

    2015-09-08

    Ethylene is a stimulant to increase natural rubber latex. After ethylene application, both fresh yield and dry matter of latex are substantially improved. Moreover, we found that ethylene improves the generation of small rubber particles. However, most genes involved in rubber biosynthesis are inhibited by exogenous ethylene. Therefore, we conducted a proteomics analysis of ethylene-stimulated rubber latex, and identified 287 abundant proteins as well as 143 ethylene responsive latex proteins (ERLPs) with mass spectrometry from the 2-DE and DIGE gels, respectively. In addition, more than 1,600 proteins, including 404 ERLPs, were identified by iTRAQ. Functional classification of ERLPs revealed that enzymes involved in post-translational modification, carbohydrate metabolism, hydrolase activity, and kinase activity were overrepresented. Some enzymes for rubber particle aggregation were inhibited to prolong latex flow, and thus finally improved latex production. Phosphoproteomics analysis identified 59 differential phosphoproteins; notably, specific isoforms of rubber elongation factor and small rubber particle protein that were phosphorylated mainly at serine residues. This post-translational modification and isoform-specific phosphorylation might be important for ethylene-stimulated latex production. These results not only deepen our understanding of the rubber latex proteome but also provide new insights into the use of ethylene to stimulate rubber latex production.

  18. 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....

  19. 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.

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

    Science.gov (United States)

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

    2016-08-16

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

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

    African Journals Online (AJOL)

    The use of the locally fabricated manual bead breaking equipment as it is being practiced today by commercial tyre repair artisans in Nigeria is characterized by drudgery. This article reports a study of the local manual bead breaking technology with a view to identifying where engineering design effort could be directed to ...

  2. Bead magnetorelaxometry with an on-chip magnetoresistive sensor

    DEFF Research Database (Denmark)

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

    2011-01-01

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

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

    DEFF Research Database (Denmark)

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

    2007-01-01

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

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

    DEFF Research Database (Denmark)

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

    2010-01-01

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

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

    DEFF Research Database (Denmark)

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

    2010-01-01

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

  6. Metallic gold beads in hyaluronic acid

    DEFF Research Database (Denmark)

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

    2013-01-01

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

  7. Switchable cell trapping using superparamagnetic beads

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-04-30

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

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

    Science.gov (United States)

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

    2014-10-15

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

  9. Self-organizing magnetic beads for biomedical applications

    CERN Document Server

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

    2011-01-01

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

  10. Fluoride removal using lanthanum incorporated chitosan beads.

    Science.gov (United States)

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

    2009-11-01

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

  11. Latex Hypersensitivity among Allergic Egyptian Children: Relation to Parental/Self Reports

    Directory of Open Access Journals (Sweden)

    Zeinab A. El-Sayed

    2014-01-01

    Full Text Available Background. Latex allergy is one of the major health concerns and allergic reactions to latex may be serious and fatal. Purpose. In this study, we sought to determine the frequency of latex hypersensitivity in a group of allergic Egyptian infants and children and its relation to the history provided by the patients or caregivers. Methods. We consecutively enrolled 400 patients with physician diagnosed allergic diseases. The study measurements included clinical evaluation for the site and duration of allergy, history suggestive of latex allergy, family history of allergy, and skin prick testing (SPT using a commercial latex extract. Results. The study revealed that 16/400 (4% patients had positive SPT; 11 of them only had positive history of sensitivity to latex. Positive latex SPT was reported in 3.4% (11/326 of patients with bronchial asthma, 5.9% (7/118 of patients with skin allergy, and 4.5% (2/44 of patients with allergic rhinitis. SPT was positive in 7.4% (4/54 of patients with concomitant respiratory and skin allergy. Latex SPT was more specific than sensitive (97.69% and 77.77%, resp. with a negative predictive value of 99.47%. Conclusion. Although underrecognized, latex is an important allergen in the pediatric age group with a sensitization frequency of 4% among allergic children. It was observed to be especially associated with multiple allergic diseases coexisting in the same patient. Pediatric allergologists should educate their patients on latex allergy and encourage the use of latex-free products.

  12. Immobilized OBOC combinatorial bead array to facilitate multiplicative screening

    Science.gov (United States)

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

    2015-01-01

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

  13. DWPF GLASS BEADS AND GLASS FRIT TRANSPORT DEMONSTRATION

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, D; Bradley Pickenheim, B

    2008-11-24

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

  14. Asthma caused by Ficus benjamina latex: evidence of cross-reactivity with fig fruit and papain.

    Science.gov (United States)

    Díez-Gómez, M L; Quirce, S; Aragoneses, E; Cuevas, M

    1998-01-01

    Ficus benjamina or weeping fig is a plant used increasingly for indoor decoration that can cause allergic rhinitis and asthma. We report a clinical and immunologic study in a patient with perennial asthma caused by F. benjamina latex in whom several episodes of angioedema of the oropharyngeal tract and tongue followed ingestion of figs and kiwi. Hypersensitivity to latex from F. benjamina and from Hevea brasiliensis, fig fruit, kiwi, papain, and bromelain was investigated by means of skin prick test, specific IgE determination by CAP, histamine release test, and bronchial provocation test to F. benjamina latex. CAP-inhibition assays were carried out to study possible cross-reactivity among these antigens. Hypersensitivity to F. benjamina latex, fig, kiwi, and proteases was demonstrated by means of skin prick test, determination of specific IgE and histamine release test. Bronchial provocation test with F. benjamina latex resulted in a dual asthmatic reaction, confirming the etiologic role of this plant. A rise of eosinophil cationic protein in patient's serum was observed 21 hours after bronchial challenge, suggesting activation of eosinophils. Inhibition assays showed that F. benjamina latex as liquid-phase inhibited up to 95% the CAP to fig and up to 57% the CAP to papain. Neither sensitization nor cross-allergenicity with H. brasiliensis latex was found. Hypersensitivity to F. benjamina latex may cause IgE-mediated respiratory allergy. The association with allergy to fig and papain is likely due to the existence of cross-reactive allergen structures.

  15. Changes in protein profile during coagulation of latex from Carica papaya

    Directory of Open Access Journals (Sweden)

    Silva L.G.

    1997-01-01

    Full Text Available We describe the changes in peptide composition by SDS-PAGE analysis of latex from Carica papaya collected at various times after incision of the unripe fruit. The data show that during latex coagulation several peptides are processed in an orderly fashion.

  16. Involvement of prostaglandins in inflammation induced by latex of Calotropis procera

    Directory of Open Access Journals (Sweden)

    Yatin M. Shivkar

    1992-01-01

    Full Text Available INTRODUCTION: The aerial parts of the plant Calotropis procera produce milky white latex that causes inflammation of the skin and mucous membranes. Prostaglandins are one of the mediators released in an inflammatory response following induction of cyclooxygenase (COX. In the present study, we have evaluated the role of prostaglandins in inflammatory response elicited by the latex of C. procera.

  17. Efficacy and phytochemical analysis of latex of Calotropis procera against selected dermatophytes.

    Science.gov (United States)

    Aliyu, Rabiu Muhammad; Abubakar, Mikaeel Bala; Kasarawa, Adamu Bello; Dabai, Yakubu Umar; Lawal, Nafiu; Bello, Muhammad Bashir; Fardami, Aminu Yusuf

    2015-01-01

    Since ancient time, increased interest has been witnessed in the use of an alternative herbal medicine for managing, and the treatment of fungal diseases worldwide. This may be connected to the cost and relative toxicities of the available antifungal drugs. It has been a known tradition practiced in the northern part of Nigeria that parents and teachers use the white latex of Calotropis procera to treat Tinea capitis in children attending the local religious school in the area. This study was conducted in 2009 to ascertain the above claim. Fresh latex of C. procera was screened for their antifungal activity against species of dermatophytes: Trichophyton spp., Microsporum spp. and Epidermophyton spp. using the agar incorporation method. The result shows that the latex inhibits the in vitro growth of these pathogenic fungi to varying extents with Trichophyton spp. being the most susceptible (P < 0.05) and thus highly inhibited by the latex followed by the Microsporum spp. and Epidermopyton spp. was least inhibited. These inhibitions followed a dose-dependent trend as undiluted latex (100%) gave the highest inhibitory impacts (P < 0.05) when compared to serially diluted latex. The phytochemical analysis of the fresh latex indicated the presence of alkaloids, saponin, tannins, steroids, flavonoids, anthraquinone, and triterpenoids. The findings of this study confirmed the perceived usefulness of the latex in the treatment of T. capitis (ringworm) practiced in our society and therefore, its use topically in the treatment of dermatomycotic infection is encouraged.

  18. Latex allergy symptoms among health care workers: results from a university health and safety surveillance system.

    Science.gov (United States)

    Epling, Carol; Duncan, Jacqueline; Archibong, Emma; Østbye, Truls; Pompeii, Lisa A; Dement, John

    2011-01-01

    We sought to describe risk factors for latex glove allergy symptoms among health care workers by combining data from an active clinical surveillance program and a comprehensive occupational health surveillance system. A total of 4,584 employers completed a latex allergy questionnaire. Six percent (n = 276) of subjects reported symptoms consistent with latex allergy. Years of latex glove use was a significant risk factor for latex allergy symptoms even after controlling for the effects of atopy, gender, age, race, fruit, and other allergies. Nurses, medical or lab technicians, physician's assistants, other clinical professionals, and housekeepers had the highest prevalence of latex glove allergy symptoms. Forty subjects (0.87%) who were confirmed as having latex sensitization. Sensitizsation may have been underestimated due to use of specific IgE antibody, less sensitive than skin-prick testing, and tiered design leading to laboratory assessment on a subset of the cohort. This surveillance program identified risk factors for latex allergy symptoms. Our findings provide a basis for tailoring future prevention strategies.

  19. Cysteine proteases from the Asclepiadaceae plants latex exhibited thrombin and plasmin like activities.

    Science.gov (United States)

    Shivaprasad, H V; Riyaz, M; Venkatesh Kumar, R; Dharmappa, K K; Tarannum, Shaista; Siddesha, J M; Rajesh, R; Vishwanath, B S

    2009-10-01

    In the present study we evaluated the presence of cysteine protease from the latex of four plants Asclepias curassavica L., Calotropis gigantea R.Br., Pergularia extensa R.Br. and Cynanchum puciflorum R.Br. belongs to the family Asclepiadaceae. Cysteine proteases from these plants latex exhibited both thrombin and plasmin like activities. Latex enzyme fraction in a concentration dependent manner induced the formation of clot in citrated blood plasma. Direct incubation of fibrinogen with latex enzyme fraction resulted in the formation of fibrin clot similar to thrombin enzyme. However prolonged incubation resulted in degradation of the formed fibrin clot suggesting plasmin like activity. Latex enzyme fraction preferentially hydrolyzed Aalpha and Bbeta chains of fibrinogen to form fibrin clot. Latex enzyme fraction also hydrolyzed the subunits of fully cross linked fibrin efficiently, the order of hydrolysis was alpha-polymer > alpha-chains > beta-chain and gamma-gamma dimer. Cysteine proteases from all the four Asclepiadaceae plants latex exhibited similar action on fibrinogen and fibrin. This study scientifically validate the use of plant latex in stop bleeding and wound healing by traditional healers all over the world.

  20. The use of fiber reinforcement in latex modified concrete overlay : final report.

    Science.gov (United States)

    2016-12-01

    The requirement to quickly reopen highways in North Carolina has motivated the increased use of rapid-setting concrete in overlays. The addition of polymer latex to the material has been used to increase the service life of the overlays. The latex mo...

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

    National Research Council Canada - National Science Library

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

    2016-01-01

    .... The coating latex is prepared from inexpensive materials and can be used for a solvent-free coating process. In addition, the ingredients of the latex are non-toxic; thus, the coated papers can be safely used for food packaging.

  2. Synthesis and characterization of core-shell acrylate based latex and study of its reactive blends.

    Science.gov (United States)

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

    2008-03-01

    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 persulfate and sodium bisulfite redox system as the initiator. Two stages seeded semi-continuous emulsion polymerization were employed for constructing a core-shell structure with P(MMA-co-BA) component as the core and P(EHA-co-GMA) component as the shell. Results of Transmission Electron Microscopy (TEM) and Dynamics Light Scattering (DLS) tests confirmed that the particles obtained are indeed possessing a desired core-shell structural character. Stable reactive latex blends were prepared by adding the latex with waterborne melamine-formaldehyde resin (MF) or urea-formaldehyde resin (UF). It was found that the glass transition temperature, the mechanical strength and the hygroscopic property of films cast from the latex blends present marked enhancements under higher thermal treatment temperature. It was revealed that the physical properties of chemically reactive latexes with core-shell structure could be altered via the change of crosslinking density both from the addition of crosslinkers and the thermal treatment.

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

    Directory of Open Access Journals (Sweden)

    Ying Nie

    2008-03-01

    Full Text Available 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 persulfate and sodium bisulfite redox system as the initiator. Two stages seeded semi-continuous emulsion polymerization were employed for constructing a core-shell structure with P(MMA-co-BA component as the core and P(EHA-co-GMA component as the shell. Results of Transmission Electron Microscopy (TEM and Dynamics Light Scattering (DLS tests confirmed that the particles obtained are indeed possessing a desired core-shell structural character. Stable reactive latex blends were prepared by adding the latex with waterborne melamine-formaldehyde resin (MF or urea-formaldehyde resin (UF. It was found that the glass transition temperature, the mechanical strength and the hygroscopic property of films cast from the latex blends present marked enhancements under higher thermal treatment temperature. It was revealed that the physical properties of chemically reactive latexes with core-shell structure could be altered via the change of crosslinking density both from the addition of crosslinkers and the thermal treatment.

  4. 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.

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

    Science.gov (United States)

    Putranto, Riza-Arief; Herlinawati, Eva; Rio, Maryannick; Leclercq, Julie; Piyatrakul, Piyanuch; Gohet, Eric; Sanier, Christine; Oktavia, Fetrina; Pirrello, Julien; Kuswanhadi; Montoro, Pascal

    2015-08-04

    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.

  6. 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...

  7. Hancornia speciosa latex for biomedical applications: physical and chemical properties, biocompatibility assessment and angiogenic activity.

    Science.gov (United States)

    Almeida, Luciane Madureira; Floriano, Juliana Ferreira; Ribeiro, Thuanne Pires; Magno, Lais Nogueira; da Mota, Lígia Souza Lima Silveira; Peixoto, Nei; Mrué, Fátima; Melo-Reis, Paulo; Lino Junior, Ruy de Souza; Graeff, Carlos Frederico de Oliveira; Gonçalves, Pablo José

    2014-09-01

    The latex obtained from Hancornia speciosa is used in folk medicine for treatment of several diseases, such as acne, warts, diabetes, gastritis and inflammation. In this work, we describe the biocompatibility assessment and angiogenic properties of H. speciosa latex and its potential application in medicine. The physical-chemical characterization was carried out following different methodologies (CHN elemental analyses; thermogravimetric analyses and Fourier transform infrared spectroscopy). The biocompatibility was evaluated through cytotoxicity and genotoxicity tests in fibroblast mouse cells and the angiogenic properties were evaluated using the chick chorioallantoic membrane (CAM) assay model. The physical-chemical results showed that the structure of Hancornia speciosa latex biomembrane is very similar to that of Hevea brasiliensis (commercially available product). Moreover, the cytotoxicity and genotoxicity assays showed that H. speciosa latex is biocompatible with life systems and can be a good biomaterial for medical applications. The CAM test showed the efficient ability of H. speciosa latex in neovascularization of tissues. The histological analysis was in accordance with the results obtained in the CAM assay. Our data indicate that the latex obtained from H. speciosa and eluted in water showed significant angiogenic activity without any cytotoxic or genotoxic effects on life systems. The same did not occur with H. speciosa latex stabilized with ammonia. Addition of ammonia does not have significant effects on the structure of biomembranes, but showed a smaller cell survival and a significant genotoxicity effect. This study contributes to the understanding of the potentialities of H. speciosa latex as a source of new phytomedicines.

  8. Effects of Oral Administration of the Latex of Calotropis procera on ...

    African Journals Online (AJOL)

    Keyword: Blood chemistry, Calotropis procera, HB, PCV, rat, weight. The latex of Calotropis procera was obtained daily and administered to groups of rats through oral cannular in different sets of study. In one set of study, the latex was administered daily at varying doses and the packed cell volume (PCV), red blood cell ...

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

    Science.gov (United States)

    Lamberti, Monica; Buonanno, Rosaria; Ritonnaro, Chiara; Giovane, Giancarlo; Crispino, Vincenzo; Feola, Antonia; Medici, Nicola; Sannolo, Nicola; Di Carlo, Angelina; Di Domenico, Marina

    2015-01-01

    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. 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. 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%). 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. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

  10. Prevalence of latex allergy in a population of patients diagnosed with myelomeningocele.

    Science.gov (United States)

    Parisi, Claudio A S; Petriz, Natalia A; Busaniche, Julio N; Cortines, María C; Frangi, Fernando A; Portillo, Santiago A; de Badiola, Francisco I

    2016-02-01

    Latex allergy is one of the main reasons of anaphylaxis in the operating room. The prevalence of this condition is higher among patients with myelomeningocele. Epidemiological data obtained from Argentine patients is scarce. To estimate the prevalence of latex sensitivity and latex allergy in a population of patients with myelomeningocele and to describe associated risk factors. Descriptive, cross-sectional, observational study. Family and personal history of allergy, number of surgeries, history of symptoms caused by having been in contact with latex or cross-reactive foods, eosinophil count, measurement of total immunoglobulin E and specific immunoglobulin E levels by means of skin and serologic testing for latex, aeroallergens and cross-reactive fruit. Eighty-two patients diagnosed with myelomeningocele were assessed: 41 were males and their average age was 15.3 ± 7.66 years old. Out of all patients, two did not complete skin and serologic testing. Among the remaining 80 patients, 16 (19.51%) had latex allergy, 46 (57.5%) were not allergic, and 18 (22%) showed sensitivity but not allergy. Having undergone more than five surgeries was a risk factor associated with latex allergy (p= 0.035). No significant association was observed with the remaining outcome measures. According to this study, the prevalence of latex allergy in this population of patients is 19.51% and the most important risk factor for this condition is a history of having undergone more than five surgeries. Sociedad Argentina de Pediatría.

  11. 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...

  12. In vitro evaluation of the effect of Euphorbia kamerunica latex on the ...

    African Journals Online (AJOL)

    The effect of Euphorbia kamerunica latex on the blood of albino rat (Rattus novergicus) was studied. Two different samples were prepared, one with 10% E. kamerunica latex in blood of albino rat and the other, whole blood. Blood from each of the two samples was analyzed haematologically for the packed cell volume ...

  13. VOLATILE ORGANIC COMPOUND EMISSIONS FROM LATEX PAINT - PART 1. CHAMBER EXPERIMENTS AND SOURCE MODEL DEVELOPMENT

    Science.gov (United States)

    Latex paints are widely used in residential and commercial indoor environments. The surface areas covered by the paints in these environments are relatively large. Thus, latex paints have the potential for having a major impact on indoor air quality (IAQ). A study was undertaken ...

  14. 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

    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

  15. 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.

  16. 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

  17. 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.

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

    Directory of Open Access Journals (Sweden)

    Meret Huber

    2016-01-01

    Full Text Available 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.

  19. 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

  20. Comparative evaluation of Type 1 latex hypersensitivity in patients with chronic urticaria, rubber factory workers and healthy control subjects

    NARCIS (Netherlands)

    Piskin, Gamze; Akyol, Aynur; Uzar, Hatice; Tulek, Necla; Boyvat, Ayse; Gurgey, Erbak

    2003-01-01

    Latex hypersensitivity manifests itself most commonly with contact urticaria. In this study, we investigated the frequency of latex hypersensitivity as a possible aetiological factor in patients with chronic urticaria (CU) and compared latex hypersensitivity of CU patients (n = 50) with that of

  1. Latex agglutination: diagnose the early cryptococcus neoformans test of capsular polysaccharide antigen.

    Science.gov (United States)

    Wang, Huanrong; Yuan, Xueqian; Zhang, Lifeng

    2015-01-01

    This paper aims to discuss the early diagnosis value of latex agglutination test in Cryptococcal meningitis. The cerebrospinal fluid (CSF) of 112 patients with definite Cryptococcal meningitis and 26 patients with tubercular meningitis and virus meningitis were collected, latex agglutination test is adopted to detect Cryptococcal capsular polysaccharide antigen. Then it was compared with fungal culture and direct microscopy method for evaluating the sensitivity and specificity of the diagnosis. The sensitivity of three methods including latex agglutination test, fungal culture and direct microscopy was 91.1%,69.6% and 73.2% respectively. The specificity of latex agglutination test was 96.0%, 100% and 100% respectively. That latex agglutination test to detect Cryptococcal capsular polysaccharide antigen could be taken as the early diagnostic method of Cryptococcus neoformans meningitis.

  2. Photonic hydrogel beads for controlled release of risedronate

    Science.gov (United States)

    Khajuria, Deepak K.; Roy Mahapatra, D.

    2014-03-01

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

  3. Ecohydraulics of Strings and Beads in Bedrock Rivers

    Science.gov (United States)

    Wohl, E.

    2016-12-01

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

  4. Thrombin like activity of Asclepias curassavica L. latex: action of cysteine proteases.

    Science.gov (United States)

    Shivaprasad, H V; Rajesh, R; Nanda, B L; Dharmappa, K K; Vishwanath, B S

    2009-05-04

    To validate the scientific basis of plant latex to stop bleeding on fresh cuts. Cysteine protease(s) from Asclepias curassavica (Asclepiadaceae) plant latex was assessed for pro-coagulant and thrombin like activities. A waxy material from the latex of Asclepias curassavica latex was removed by freezing and thawing. The resulted latex enzyme fraction was assayed for proteolytic activity using denatured casein as substrate. Its coagulant activity and thrombin like activity were determined using citrated plasma and pure fibrinogen, respectively. Inhibition studies were performed using specific protease inhibitors to know the type of protease. The latex enzyme fraction exhibited strong proteolytic activity when compared to trypsin and exerted pro-coagulant action by reducing plasma clotting time from 195 to 58 s whereas trypsin reduced clotting time marginally from 195 to 155 s. The pro-coagulant activity of this enzyme fraction was exerted by selectively hydrolyzing A alpha and B beta subunits of fibrinogen to form fibrin clot when pure fibrinogen was used as substrate as assessed by fibrinogen-agarose plate method and fibrinogen polymerization assay. Trypsin failed to induce any fibrin clot under similar conditions. The electrophoretic pattern of latex enzyme fraction-induced fibrin clot was very much similar to that of thrombin-induced fibrin clot and mimic thrombin like action. The proteolytic activity including thrombin like activity of Asclepias curassavica latex enzyme fraction was completely inhibited by iodoaceticacid (IAA). Cysteine proteases from Asclepias curassavica latex exhibited strong pro-coagulant action and were found to be specific in its action (Thrombin like). This could be the basis for the use of plant latex in pharmacological applications that justify their use as folk medicine.

  5. [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.

  6. The influence of aggregation of latex particles on membrane fouling attachments & ultrafiltration performance in ultrafiltration of latex contaminated water and wastewater.

    Science.gov (United States)

    Abdelrasoul, Amira; Doan, Huu; Lohi, Ali; Cheng, Chil-Hung

    2017-02-01

    The goal of the present study was to investigate the influence of latex particle aggregation on membrane fouling attachments and the ultrafiltration performance of simulated latex effluent using Cetyltrimethyl Ammonium Bromide (CTAB) as a cationic surfactant. Hydrophilic polysulfone and ultrafilic flat heterogeneous membranes, with molecular weight cut off (MWCO) of 60,000 and 100,000, respectively, as well as hydrophobic polyvinylidene difluoride with MWCO of 100,000, were used under a constant flow rate and cross-flow mode in ultrafiltration of latex solution. In addition, a polycarbonate flat membrane with uniform pore size of 0.05μm was likewise used during the experiment. The effects of CTAB on the latex particle size distribution were investigated at various concentrations, different treatment times, and diverse agitation duration times. The effects of CTAB on the zeta potential of membrane surfaces and latex particles were also investigated. The data obtained indicate that the particle size distribution of treated latex effluent experienced significant shifts in the peaks toward a larger size range caused by the aggregation of particles. As a result, the mass of fouling contributing to pore blocking and the irreversible fouling were noticeably reduced. The optimum results occurred in the instance when CTAB was added at the critical micelle concentration of 0.36g/L, for the duration of 10min and with minimal agitation. Notably, a higher stirring rate had an overall negative effect on the membrane fouling minimization. Copyright © 2016. Published by Elsevier B.V.

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

    DEFF Research Database (Denmark)

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

    2007-01-01

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

  8. Metronidazole release using natural rubber latex as matrix

    Directory of Open Access Journals (Sweden)

    Rondinelli Donizetti Herculano

    2010-03-01

    Full Text Available Natural Rubber Latex (NRL can be used successfully in controlled release drug delivery due to their excellent matrix forming properties. Recently, NRL has shown to stimulate angiogenesis, cellular adhesion and the formation of extracellular matrix, promoting the replacement and regeneration of tissue. A dermatological delivery system comprising a topically acceptable, inert support impregnated with a metronidazole (MET solution was developed. MET 2-(2- methyl- 5-nitro- 1H- imidazol- 1-yl ethanol, has been widely used for the treatment of protozoa and anaerobic bacterial infections. MET is a nitroimidazole anti-infective medication used mainly in the treatment of infections caused by susceptible organisms, particularly anaerobic bacteria and protozoa. In a previous study, we have tested NRL as an occlusive membrane for GBR with promising results. One possible way to decrease the inflammatory process, it was incorporated the MET in NRL. MET was incorporated into the NRL, by mixing it in solution for in vitro protein delivery experiments. The solutions of latex and MET were polymerized at different temperatures, from -100 to 40 °C, in order to control the membrane morphology. SEM microscopy analysis showed that the number, size and distribution of pores in NRL membranes varied depending on polymerization temperature, as well as its overall morphology. Results demonstrated that the best drug-delivery system was the membrane polymerized at -100 °C, which does release 77,1% of its MET content for up 310 hours.

  9. Extract from Calotropis procera latex activates murine macrophages.

    Science.gov (United States)

    Seddek, Abdel latif Shaker; Mahmoud, Motamed Elsayed; Shiina, Takahiko; Hirayama, Haruko; Iwami, Momoe; Miyazawa, Seiji; Nikami, Hideki; Takewaki, Tadashi; Shimizu, Yasutake

    2009-07-01

    Calotropis procera latex has long been used in traditional medicines. Extracts from C. procera latex have been reported to have various pharmacological actions, including protection from myocardial infarction, hepatoprotective action, antitumor activity, antinociceptive, and pro- and anti-inflammatory actions. To evaluate the immunomodulatory functions of the water-soluble C. procera extract (CPE), we investigated its ability to activate macrophages-effector cells in inflammatory and immune responses. Intraperitoneal injection of CPE in mice (2 mg/mouse) induced migration of macrophages to the intraperitoneal cavity, confirming the proinflammatory effects of water-soluble CPE. The direct effects of CPE on macrophages were then assessed by measuring the production of nitric oxide (NO) as an indicator for macrophage activation. Addition of CPE (1-10 microg/ml) to the culture medium of the murine monocyte/macrophage cell line RAW264.7 caused an increase in NO production in a time- and dose-dependent manner. CPE-elicited NO production was blocked by application of an inhibitor of inducible nitric oxide synthase (iNOS). Expression of iNOS mRNA was induced by treatment of cultured macrophages with CPE. Injection of CPE in mice also resulted in an increase in plasma NO level. The results suggest that CPE activates macrophages and facilitates NO production via up-regulation of iNOS gene expression.

  10. Ocular toxicity by latex of Calotropis procera (Sodom apple

    Directory of Open Access Journals (Sweden)

    Basak Samar

    2009-01-01

    Full Text Available 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% had iridocyclitis, and seven (24% had associated secondary glaucoma. After treatment with topical corticosteroids, antiglaucoma agents, cycloplegics, hypertonic saline and tears supplements, 27 (93% eyes recovered completely within 3-14 days. After three months, 17 (74% out of 23 eyes showed a significant low endothelial cell count compared to the normal fellow eye ( P 0.001. The latex of Calotropis procera causes significant ocular morbidity which may be preventable by simple health education. The long-term effect on corneal endothelium has to be studied further.

  11. Prevention of allergy to acrylates and latex in dental personnel.

    Science.gov (United States)

    Ohlson, Carl-Göran; Svensson, Lisbeth

    2002-01-01

    Contact allergy to acrylate monomers and immediate hypersensitivity to latex gloves in dental personnel calls for preventive measures to reduce the risks. The aim of the study was to evaluate the preventive effect of an information campaign after a 3-year follow-up. The campaign included instructions and training according to an ordinance, both in writing and orally, e.g. concerning the choice of products and protection devices and the proper handling of the materials. The follow-up was carried out through 1997-2000 and included all eligible 513 subjects. Information on new cases was ascertained by a questionnaire and reports from the occupational health service and the department of dermatology. The number of expected new cases was based on the incidence rate, derived from a preceding prevalence study in the same county, and the exposed years at risk in the follow-up period. No new case of allergy to acrylates or latex rubber was found in the follow-up period as against 4.91 expected (p = 0.007). In conclusion, this study indicates that occupational allergies can be prevented successfully, but requires vigorous measures to influence the behaviour and the routines of daily work in dental practice.

  12. [Latex covering and mechanical analysis of balloon expandable stents].

    Science.gov (United States)

    Marty, B; von Segesser, L K; Carrel, T; Turina, M

    1996-01-01

    To the moment a few stents of metallic coils or meshes are available with a sealing coverage. In the present study balloon-expandable stents have been covered with a thin layer of natural rubber latex. The physical properties of these impervious stents were compared to the conventional stents. The expansion, the loss of expansion and the deformity during and after balloon inflation have been analyzed. In the pressure zone of 4-6 bar the mechanical characteristics of the impervious stents were similar to the conventional stents. The stents were expanded at 100% related on the balloon diameter used for expansion. Additional pressure of 1 bar was necessary to expand the impervious stents. At balloon pressure below 4 bar the stents tied the balloons in the midzone. The impervious stents, expanded at 6, 8 and 10mm, underwent a loss of expansion of 10% after withdrawal of the balloons. Their configuration was barrel-shaped (4% central enlargement) due to the latex rubber, constricting the wire meshes at both ends. These preliminary results are encouraging and allow further investigations.

  13. Tomato allergy in children and young adults: cross-reactivity with latex and potato.

    Science.gov (United States)

    Reche, M; Pascual, C Y; Vicente, J; Caballero, T; Martín-Muñoz, F; Sanchez, S; Martín-Esteban, M

    2001-12-01

    Several studies have shown that allergy to natural rubber latex is associated with cross-reactivity to certain foods such as tomato and potato. The objective was to investigate the clinical and immunologic differences between a group of patients with clinical allergy to tomato and latex and another which had only clinical allergy to tomato. We also aimed to assess, in vitro, the relationship of tomato and latex allergens, which could explain the cross-reactivity. Forty patients with histories of adverse reactions to tomato and IgE-mediated hypersensitivity were enrolled in the study. Tomato, latex, and potato components were analyzed by SDS-PAGE immunoblotting. CAP and immunoblot inhibition were used to study allergen cross-reactivity. Patients from group A had a mean age of 13.2 years, and in group B the mean age was 21.7 years. In group B, 9/10 patients belonged to the latex-fruits syndrome. All patients of both groups tolerated potato. Immunoblotting patterns obtained with patients' sera from pool A showed IgE-binding bands to tomato ranging from 44 to 46 kDa and a triple band at 67 kDa. For latex, there was a strong binding at 44 kDa, and potato showed a strong band of 44 kDa and a 67-kDa triple band. In pool B, the binding to the band of 44 kDa in latex and tomato was more intense than in pool A. In pool A, immunoblot inhibition with potato allergen showed an intense inhibition of the three allergens (potato, latex, and tomato); with latex, inhibition was partial and with tomato, a complete inhibition of tomato and latex was observed, and a partial inhibition of potato. In pool B, the inhibition pattern followed a similar tendency to pool A. The CAP inhibition confirmed the high rate of cross-reactivity between tomato, potato, and latex. In our study, tomato, potato, and latex showed a common band of 44-46 kDa probably corresponding to patatin. This protein could be implicated in the high cross-reactivity between tomato, latex, and potato observed in the

  14. Specific IgE response to purified and recombinant allergens in latex allergy

    Directory of Open Access Journals (Sweden)

    Arif Siti AM

    2005-08-01

    Full Text Available Abstract Background In recent years, allergy to natural rubber latex has emerged as a major allergy among certain occupational groups and patients with underlying diseases. The sensitization and development of latex allergy has been attributed to exposure to products containing residual latex proteins. Although improved manufacturing procedures resulted in a considerable reduction of new cases, the potential risk for some patient groups is still great. In addition the prevalent cross-reactivity of latex proteins with other food allergens poses a major concern. A number of purified allergens and a few commercial kits are currently available, but no concerted effort was undertaken to evaluate them. Methods We studied 11 purified latex allergens, Hev b 1 to Hev b 10, and Hev b 13 along with several crude allergen extracts and two commercial ImmunoCAP assays to evaluate specific IgE antibody in the sera from latex allergic patients and controls. Health care workers and spina bifida patients with clinical symptoms of latex allergy, spina bifida patients without latex allergy, and non-atopic health care workers have been studied. Results The results suggest that Hev b 2, 5, 6, and 13 together identified over 80 percent health care workers with latex allergy, while Hev b 6 along with Hev b 1 or 3 detected specific IgE antibody in all sera studied from patients with spina bifida and latex allergy. The ImmunoCAP results using both Hev b 5 amplified and non-amplified closely agreed with the clinical diagnosis of latex allergy in health care workers and in spina bifida. Conclusion Although the purified allergens and crude extracts reacted diversely with IgE from different patient groups, the results indicated that use of certain combinations of purified recombinant antigens will be useful in commercial kits or in in-house assays for detecting specific IgE antibody in the sera. The results suggest that a combination of Hev b 2, 3, 5, 6, and 13 together

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

    CERN Document Server

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

    2013-01-01

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

  16. More About Cutting Tool For Shaving Weld Beads

    Science.gov (United States)

    Oelgoetz, Peter A.; Davis, William M.

    1996-01-01

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

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

    Science.gov (United States)

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

    2016-05-04

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

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

    Science.gov (United States)

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

    2013-04-05

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

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

    Science.gov (United States)

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

    2012-01-01

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

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

    Science.gov (United States)

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

    2014-06-01

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

  1. Lightweight High Strength Concrete with Expanded Polystyrene Beads

    OpenAIRE

    Subhan, Tengku Fitriani L

    2006-01-01

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

  2. Adsorption Capacity of Chitosan Beads in Toxic Solutions

    OpenAIRE

    P. Setthamongkol; J. Salaenoi

    2012-01-01

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

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

    OpenAIRE

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

    2014-01-01

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

  4. Profiling Ethylene-Responsive Genes Expressed in the Latex of the Mature Virgin Rubber Trees Using cDNA Microarray.

    Science.gov (United States)

    Nie, Zhiyi; Kang, Guijuan; Duan, Cuifang; Li, Yu; Dai, Longjun; Zeng, Rizhong

    2016-01-01

    Ethylene is commonly used as a latex stimulant of Hevea brasiliensis by application of ethephon (chloro-2-ethylphosphonic acid); however, the molecular mechanism by which ethylene increases latex production is not clear. To better understand the effects of ethylene stimulation on the laticiferous cells of rubber trees, a latex expressed sequence tag (EST)-based complementary DNA microarray containing 2,973 unique genes (probes) was first developed and used to analyze the gene expression changes in the latex of the mature virgin rubber trees after ethephon treatment at three different time-points: 8, 24 and 48 h. Transcript levels of 163 genes were significantly altered with fold-change values ≥ 2 or ≤ -2 (q-value latex actin cytoskeleton might play important roles in ethylene-induced increase of latex production. The results may provide useful insights into understanding the molecular mechanism underlying the effect of ethylene on latex metabolism of H. brasiliensis.

  5. Molluscicidal effect of Euphorbia umbellata (Pax Bruyns latex on Biomphalaria glabrata, Schistosoma mansoni host snail

    Directory of Open Access Journals (Sweden)

    Luciana Patrícia Lima Alves Pereira

    2017-12-01

    Full Text Available ABSTRACT Euphorbia umbellata (Pax Bruyns is an easily cultivated shrub, with occurrence in the tropical regions of the American and African continents. Chemical studies have revealed that the latex of this plant is rich in terpene compounds, which are highly toxic to snails Biomphalaria glabrata (Basommatophora: Planorbidae. The aim of this study was to evaluate the chemical composition and molluscicidal activity of the latex produced by E. umbellata, as well as the safety of its application in aquatic environments. The concentration of latex that killed 90% of the exposed snails after 24 h exposure (LC90 was 3.69 mg/L. Toxicity bioassays using Danio rerio (zebrafish revealed that these animals were less susceptible to latex than planorbids. However, it is important to perform other toxicity tests to ensure the feasibility of using latex to control populations of mollusks that contribute to schistosomiasis transmission. A phytochemical screening performed with the E. umbellata latex identified the triterpenoid and coumarin class. Further studies are warranted to isolate, identify, and test the active compounds of E. umbellata latex in B. glabrata.

  6. Frequency in allergy to proteins of latex in health care workers.

    Science.gov (United States)

    Moreno, H L; Avila, E; Angulo, Y; Portillo, J; Moreno, L; Reza, G; Hernández, V; Levario, M

    2005-01-01

    The objective of this study is to evaluate allergy prevalence to latex proteins in health care workers at the Laboratory and Surgery Room of Hospital CIMA Chihuahua. A thorough clinical chart was recorded for all health care workers studied: hematic biometry, total IgE by ELISA method, specific IgE to latex antigen by ELISA (pharmacy CAP system), cutaneous tests with latex antigen (Aphi de México, Hevea Brasiliensis Biopal Inc. Spoken WA), through scarification, together with histamine and Evans (positive-negative control). The number included is 99 individuals. Specific IgE to latex in 4 cases was positive (4%) and in the cutaneous tests to latex, 24 cases (24%) resulted positive. The study reports a prevalence of (4%) when performing the specific IgE to latex and (24%) to the cutaneous test with antigen to total latex. This data allows us to continue evaluating the personnel at risk at the hospital, with better results in the administration of Labor Medicine at this medical institution.

  7. In vitro antiviral activity of Ficus carica latex against caprine herpesvirus-1.

    Science.gov (United States)

    Camero, Michele; Marinaro, Mariarosaria; Lovero, Angela; Elia, Gabriella; Losurdo, Michele; Buonavoglia, Canio; Tempesta, Maria

    2014-01-01

    The latex of Ficus carica Linn. (Moraceae) has been shown to possess antiviral properties against some human viruses. To determine the ability of F. carica latex (F-latex) to interfere with the infection of caprine herpesvirus-1 (CpHV-1) in vitro, F-latex was resuspended in culture media containing 1% ethanol and was tested for potential antiviral effects against CpHV-1. Titration of CpHV-1 in the presence or in the absence of F-latex was performed on monolayers of Madin Darby Bovine Kidney (MDBK) cells. Simultaneous addition of F-latex and CpHV-1 to monolayers of MDBK cells resulted in a significant reduction of CpHV-1 titres 3 days post-infection and this effect was comparable to that induced by acyclovir. The study suggests that the F-latex is able to interfere with the replication of CpHV-1 in vitro on MDBK cells and future studies will determine the mechanisms responsible for the observed antiviral activity.

  8. N Latex FLC serum free light-chain assays in patients with renal impairment.

    Science.gov (United States)

    Jacobs, Joannes F M; Hoedemakers, Rein M J; Teunissen, Elisa; Te Velthuis, Henk

    2014-06-01

    The aim of this study was to establish ranges for N Latex free light-chain (FLC) monoclonal-based nephelometric assays in patients with renal impairment. In this retrospective study, serum samples from 284 patients with chronic kidney disease (CKD) stages 1-5 were measured with N Latex and Freelite FLC reagents on the Siemens BNII system and compared with controls without renal impairment. Both κFLC and λFLC concentrations increased with the N Latex FLC and the Freelite assays with each increment in CKD stage. No difference was found in FLC κ concentrations between the two methods. In patients with renal failure, N Latex FLC detected higher concentrations of λFLC (CKD5 median, 128 mg/L; 95% range, 43-302) compared with Freelite (89.5 mg/L, 35-197) (pLatex reference limits for healthy controls (0.31-1.56). The N Latex FLC κ/λ ratio in the CKD5 group (0.69, 0.32-1.54) was significantly lower compared with the control group (pLatex FLC κ/λ ratio in patients with renal failure did not differ from the reference limits for healthy controls.

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

    Science.gov (United States)

    Kocaturk, Selin; Yagar, Hulya

    2010-05-01

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

  10. Physicochemical Characterization of Alginate Beads Containing Sugars and Biopolymers

    Directory of Open Access Journals (Sweden)

    Tatiana Aguirre Calvo

    2016-01-01

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

  11. Immunological and allergenic responses induced by latex fractions of Calotropis procera (Ait.) R.Br.

    Science.gov (United States)

    Ramos, M V; Aguiar, V C; Melo, V M M; Mesquita, R O; Silvestre, P P; Oliveira, J S; Oliveira, R S B; Macedo, N M R; Alencar, N M N

    2007-04-20

    Immunological and allergenic responses against the latex of Calotropis procera were investigated in mice by oral and subcutaneous routes. The latex was fractionated according to water solubility and molecular size of its components. The fractions were named as non-dialyzable latex (NDL) corresponding to the major latex proteins, dialyzable latex (DL) corresponding to low molecular size substances and rubber latex (RL) which was highly insoluble in water. Anti-sera against these fractions were assayed for total IgG and IgA titration by ELISA and IgE and IgG(1) were quantified by passive cutaneous anaphylaxis (PCA) in rats and mice, respectively. None of the fractions induced antibodies level increases when mice received latex fractions by oral route and thus, did not develop allergy. Nonetheless, anti-sera of mice sensitized with NDL and RL by subcutaneous route displayed considerable immunological response while DL did not. IgG level augmented consistently against NDL and RL while IgA response was detected only to NDL. NDL and RL induced very strong PCA reactions suggesting that both fractions would contain latex substances involved in allergy. Furthermore, protein analysis of NDL and RL suggests that RL still retain residual proteins abundantly found in NDL that could explain its similar allergenic effect. No IgG(1) reaction was detected in any of the anti-sera tested. According to the results, the proteins of latex of Calotropis procera can provoke allergy by subcutaneous route. The NDL has previously shown to display anti-inflammatory and analgesic activities by intraperitoneal injection. It should be relevant to determine whether NDL could induce such activities when assayed by oral route since it was ineffective to induce allergy by this way.

  12. Evaluating interventions aimed at reducing occupational exposure to latex and rubber glove allergens.

    Science.gov (United States)

    Turner, Susan; McNamee, Roseanne; Agius, Raymond; Wilkinson, Stephen Mark; Carder, Melanie; Stocks, Susan J

    2012-12-01

    Concerns over occupational exposures to blood-borne viruses resulted in increased protective glove use; consequentially latex allergy became a hazard for some occupational groups. Interventions aimed at managing this problem included substitution measures (eg, non-powdered/non-latex gloves), but such changes may not occur simultaneously across occupational sectors. This study evaluated whether the incidence of occupational dermatoses fell after interventions aiming to reduce exposure to 'latex and rubber glove allergens' ('latex') were introduced, and whether these interventions were more effective for healthcare workers (HCWs), compared with non-HCWs. Incidence rate ratios (IRRs) comparing cases reported to EPIDERM (a UK-wide surveillance scheme) during post versus pre-intervention periods were calculated, both where 'latex' was cited and for cases associated with other exposures ('controls'). Among HCWs, cases of contact urticaria and allergic contact dermatitis (ACD) where 'latex' was cited showed significant downward trends post-intervention, with IRRs of 0.72, 95% CI; 0.52 to 1.00 and 0.47, 95% CI; 0.35 to 0.64 respectively. For HCWs, this fall in 'latex' associated ACD was significantly greater (p=0.02) than for other exposures ('controls') IRR=0.85, 95% CI; 0.57 to 1.28, and greater than that among non-HCWs (IRR 0.75, 95% CI; 0.61 to 0.93). Increases over time were seen for irritant contact dermatitis (ICD) reporting for HCWs, both for cases associated with 'latex' (IRR 1.47, 95% CI: 1.02 to 2.13) and for other exposures ('controls') IRR 1.36, 95% CI 1.06 to 1.76, but not for non-HCWs. A reduction in overall ACD, particularly in HCWs, coincided with interventions aimed at managing workplace contact dermatoses associated with 'latex' exposure. A coincidental rise in ICD reporting is also important, both for hand care and for infection control strategies.

  13. Effect of silica fume and SBR latex on the pasteaggregate interfacial transition zone

    Directory of Open Access Journals (Sweden)

    João Adriano Rossignolo

    2007-03-01

    Full Text Available This paper deals with the effect of silica fume and styrene-butadiene latex (SBR on the microstructure of the interfacial transition zone (ITZ between Portland cement paste and aggregates (basalt. Scanning Electron Microscope (SEM equipped with energy dispersive x ray analysis system (EDX was used to determine the ITZ thickness. In the plain concrete a marked ITZ around the aggregate particles (55 µm was observed, while in concretes with silica fume or latex SBR the ITZ was less pronounced (35-40 µm. However, better results were observed in concretes with silica fume and latex SBR (20-25 µm.

  14. Glove powder's carrying capacity for latex protein: analysis using the ASTM ELISA test.

    Science.gov (United States)

    Beezhold, D; Horton, K; Hickey, V; Daddona, J; Kostyal, D

    2003-01-01

    Glove donning powders carry latex proteins and disperse them into the workplace environment. We have used the ASTM D6499 ELISA to quantify the amount of latex antigen bound to and carried by glove powders. We could differentiate between a small amount of protein actually bound to the powders and a larger amount carried by the powder. Enhanced binding of a major allergen, Hev b 5, to the starch powders was demonstrated by Western blot. The D6499 ELISA is able to measure total latex antigen, soluble and powder bound, simultaneously without the need to centrifuge the samples.

  15. Latex allergy and its clinical features among healthcare workers at Mankweng Hospital, Limpopo Province, South Africa.

    Science.gov (United States)

    Risenga, S M; Shivambu, G P; Rakgole, M P; Makwela, M L; Nthuli, S; Malatji, T A P; Maligavhada, N J; Green, R J

    2013-03-15

    Latex allergy, caused by sensitisation in atopic individuals, is a common occupational disease among healthcare workers who use latex gloves. It may be present in non-atopic individuals as well. The main objective of this study was to document the prevalence and disease spectrum of latex allergy at Mankweng Hospital, Limpopo Province, South Africa. The secondary objective was to determine clinical presentation of the disease. A cross-sectional descriptive study, with an analytical component, was conducted among healthcare workers who worked in high-risk areas for latex sensitisation. ImmunoCAP testing was performed and followed by a skin-prick test (SPT) in those who tested negative to the blood test. Two hundred screening questionnaires were distributed to healthcare workers at the hospital. Of these 158 (79.0%) were returned, with 59 participants meeting the inclusion criteria (experiencing symptoms due to wearing latex gloves). The mean age of the participants was 39.6 years (standard deviation 9.8 years, range 20 - 60 years). There were more females (98.1%) than males (1.9%). Glove-related symptoms were present in 59 subjects (37.1%), in 7 (11.9%) of whom the ImmunoCAP was positive to latex (95% confidence interval 4.2 - 22.9%). Fourteen participants were lost to follow-up before the SPT was performed. Thirty-eight of the participants with negative ImmunoCAP tests underwent SPT. Positive SPTs were reported in 5 of these 38 workers (13.2%), indicating that the ImmunoCAP test missed 11.1% (5/45) of latex-allergic individuals. The prevalence of latex allergy in this study was 8.3% (12/144). A denominator of 144 was used, as there is a possibility that some of the 14 individuals lost to follow-up could have tested positive to latex sensitisation by SPT. The symptoms experienced by latex-sensitised workers were rhinitis (100.0%), asthma (50.0%), dermatitis (25.0%), severe anaphylaxis (8.3%), abdominal pain (8.3%) and angio-oedema (8.3%). Our findings reveal that

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

    Directory of Open Access Journals (Sweden)

    Chen-Lin Soo

    2017-01-01

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

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

    DEFF Research Database (Denmark)

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

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

  18. Lipoxygenase inhibitors from the latex of Calotropis Procera.

    Science.gov (United States)

    Abdel-Mageed, Wael M; Mohamed, Nadia H; Liu, Miaomiao; El-Gamal, Ali A; Basudan, Omer A; Ismail, Mady Ahmed; Quinn, Ronald J; Liu, Xueting; Zhang, Lixin; Shoreit, Ahmed A M

    2016-03-09

    A radical-scavenging, guided phytochemical study of the latex of Calotropis Procera afforded five lignans (1-5), including a new one (4). The structural determination was accomplished using 1D- and 2D-NMR, high-resolution electrospray ionization mass spectrometry (HRESIMS), and correlation with known compounds. Among the isolated compounds, acylated lignans (3-5) showed stronger antioxidant activity than non-acylated derivatives (1,2). Anti-inflammatory activity was evaluated by determining the inhibitory potential against 5- and 15-lipoxygenase enzymes. The highest anti-inflammatory activity was observed in compound 4, with IC50s values of 7.6 µM and 2.7 µM against 5-LOX and 15-LOX, respectively.

  19. Occupational Latex Allergy: the Current State of Affairs.

    Science.gov (United States)

    Vandenplas, Olivier; Raulf, Monika

    2017-03-01

    Allergy to natural rubber latex (NRL) reached epidemic proportions during the nineties and led to intense preventive efforts. The aim of this review was to provide a comprehensive compilation of the current status of occupational NRL allergy. Recent advances led to the characterization of 15 NRL allergens and the development of assays for measuring the allergen content of NRL materials and specific IgE antibodies against NRL allergen components. Preventive measures aimed at reducing workplace exposure to NRL allergens were associated with decreasing incidence rates of NRL allergy. However, a pooled analysis of epidemiological surveys published during the last 10 years provided prevalence estimates of NRL sensitization and allergy similar to those derived from studies conducted before 2003. Substantial progress has been made in the understanding and prevention of NRL allergy, although the disease may still remain a worldwide cause of concern.

  20. Convertisseur d'équations LATEX2Ink

    OpenAIRE

    Montaser Awal, A.; Cousseau, R.; Viard-Gaudin, C.

    2008-01-01

    International audience; Dans cet article nous présentons un outil de génération de formules mathématiques manuscrites en ligne à partir d'une chaîne LATEX. Ce générateur permettra facilement de fabriquer à partir d'un corpus de référence d'expressions mathématiques une base de données qui sera annotée automatiquement au niveau symbole. Ainsi, à partir d'une base de symboles isolés, nous pouvons produire de façon pseudo-synthétique une formule mathématique quelconque par un placement et un dim...

  1. 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.

  2. Latex proteins from Calotropis procera: Toxicity and immunological tolerance revisited.

    Science.gov (United States)

    Bezerra, Camila F; Mota, Érika F; Silva, Ana Claudia M; Tomé, Adriana R; Silva, Maria Z R; de Brito, Daniel; Porfírio, Camila T M N; Oliveira, Ariclécio C; Lima-Filho, José V; Ramos, Márcio V

    2017-08-25

    Many thousands of plants are disseminated worldwide in traditional and folk medicines based on the belief that their leaves, roots, seeds, bark or secretions, when adequately handled, can treat, alleviate or ameliorate numerous disease symptoms. Calotropis procera (Apocynaceae) is a popular medicinal plant and the claims of this shrub's phytomedicinal properties have been scientifically validated. In this study, further prospects towards the in vivo toxicity and oral immunological tolerance of phytomodulatory proteins isolated from the latex of C. procera are reported. Acute toxicity was determined in mice by oral and intraperitoneal administration of latex proteins (LP) and was followed behavioral, hematological and histological analyses. Oral immunological tolerance to LP was assessed by intraperitoneal immunization in mice that had received LP orally before. Animals given 5000 mg/kg orally exhibited only discrete behavioral alterations and augmentation of monocytes. Death was not notified 14 days after exposure. However, all animals receiving LP 150 mg/kg by i.p. died in 1 h. Death (20%) was documented when LP (75 mg/kg) was given in the peritoneum and signs of harmful effects were observed in the survivors (80%). Oral immunological tolerance was observed in animals previously given LP orally, when they were further immunized/challenged with peritoneal exposure to different doses of LP. This was confirmed by the lowering of IgE and IgG in the serum, IL-4 and IFN-γ in spleen homogenates and the absence of anaphylaxis signs. It is therefore concluded that LP exhibited quite discrete adverse effects when orally administrated at higher concentrations and this route of administration did not stimulate adverse immunological reactions. Instead it was observed immunological tolerance. The present study contributes very important information concerning the safe use of C. procera as a phytotherapeutic agent. Copyright © 2017. Published by Elsevier B.V.

  3. Studies on biotransformation of Calotropis procera latex - a renewable source of petroleum, value-added chemicals, and products

    Energy Technology Data Exchange (ETDEWEB)

    Behera, B.K.; Arora, M.; Sharma, D.K.

    2000-10-01

    Petroleum reserves of the world may not last forever. There is a need to develop alternative and renewable sources of petroleum. Petrocrops (wild and waste plants) are renewable sources of petroleum hydrocarbons. Calotropis procera is one of the potential candidates for petrofarming. The latex obtained from C. procera may be hydrocracked to obtain hydrocarbons. This involves severe thermochemical conditions. Biodegradation of latex may afford a milder and less energy-intensive technique of latex degradation. In the present work, the latex obtained from C. procera has been subjected to microbial treatment using different fungi and bacteria. The biotransformed and biodegraded latex showed enhancement in the heptane extraction in comparison to that of untreated latex. The biotransformed and biodegraded latex was subjected to {sup 1}H-NMR, {sup 13}C-NMR, and FTIR spectral analysis. The latex was found to have undergone demethylation, dehydrogenation, carboxylation, and aromatization during microbial treatment. Average molecular weight of the latex compounds was found to have decreased as a result of microbial treatment. The biotransformed and biodegraded latex may be hydrotreated to obtain petroleum and other value-added chemicals and cleaner fuels. (Author)

  4. 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.

  5. Molecular and biochemical evaluation of genetic effect of Calotropis procera (Ait.) latex on Aspergillus terreus (Thom).

    Science.gov (United States)

    Qari, Sameer H

    2008-10-01

    The present study was conducted to observe the genotoxic effect of latex of Calotropis procera. Dense conidial suspensions of Aspergillus terreus Thorn were treated with different concentrations of Calotropis latex and assayed for percentage survival, auxotrophic mutants, DNA and total protein contents and further subjected to RAPD and SDS-PAGE tests. It was found that latex of Calotropis procera had potent lethal and mutagenic activities. Percentage survival 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 which were the 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 latex of Calotropis procera.

  6. Biochemical analysis of a papain-like protease isolated from the latex of Asclepias curassavica L

    National Research Council Canada - National Science Library

    Liggieri, Constanza; Obregón, Walter; Trejo, Sebastián; Priolo, Nora

    2009-01-01

    ... and secondary metabolites. A new papain-like endopeptidase (asclepain cII) has been isolated and characterized from the latex extracted from petioles of Asclepias curassavica L. (Asclepiadaceae...

  7. Synthesis and applications of MANs/poly(MMA-co-BA) nanocomposite latex by miniemulsion polymerization.

    Science.gov (United States)

    Gong, Sheng; Chen, Huayao; Zhou, Xinhua; Gunasekaran, Sundaram

    2017-11-01

    We have synthesized core-shell structured 3-methacryloxypropyltrimethoxysilane (MPS) functionalized antimony-doped tin oxide nanoparticles (MANs)-poly(methyl methacrylate-co-butyl acrylate) (PMMA-co-BA, PMB) nanocomposite latex particles via miniemulsion polymerization method. Polymerizable anionic surfactant DNS-86 (allyloxy polyoxyethylene(10) nonyl ammonium sulfate) was first introduced to synthesize core-shell nanocomposite. The morphologies of synthesized MANs and MANs/PMB latex nanocomposite particles were studied with transmission electron microscopy, which revealed particles, on average 70 nm in size, with a core-shell structure. Owing to the uniformity and hydrophobicity of MANs, the MANs-embedded PMB latex nanocomposite can be tailored more precisely than other nanoparticles-embedded nanocomposites. Films incorporating 10 wt% of MANs in the MAN/PMB latex nanocomposite exhibit good transmittance in the visible region, and excellent opacity in the near infrared region. The MANs/PMB nanocomposite film also appears suitable for heat insulation applications.

  8. 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.

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

    Science.gov (United States)

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

    2009-01-01

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

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

    Science.gov (United States)

    Jagadeesh, Shreesha; Chen, Lu; Aitchison, Stewart

    2016-03-01

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

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

    Science.gov (United States)

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

    2015-09-04

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

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

    Science.gov (United States)

    Kim, Hyejin; Lee, Jong Bum

    2016-05-01

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

  13. Removal of uranium from aqueous solution by aliginate beads

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-04-15

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

  14. Removal of Uranium from Aqueous Solution by Alginate Beads

    Directory of Open Access Journals (Sweden)

    Jing Yu

    2017-04-01

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

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

    Science.gov (United States)

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

    2017-10-01

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

  16. 515 Prevalence of Latex Sensitization Between Medicine and Dentistry Students from Nuevo Leon University

    OpenAIRE

    González, Arya; González-Díaz, Sandra; Arias-Cruz, Alfredo; Macías-Weinmann, Alejandra; Rodríguez, Pablo

    2012-01-01

    Background Latex allergy has become an important health problem in the last 2 decades. Sensitization in general population is about 1%.1 Healthcare workers have a frequency of 2% to 25%.2 There is not information about this issue in Mexico. Our objective was to know and compare prevalence of latex sensitization in last grade medicine and dentistry students of the Nuevo Leon University. Methods This was an observational, prospective and comparative study. Last grade medicine and dentistry stud...

  17. Estimation of some alkaloids in the capsule and stem latex of papaver somniferum L

    Energy Technology Data Exchange (ETDEWEB)

    Guerkan, E. (Cekmece Nuclear Research and Training Center, Istanbul (Turkey))

    1983-06-01

    The contents of morphine and its N-oxides, codeine and thebaine in the capsule and stem latex of Papaver somniferum L. are being estimated by using N-methyl-/sup 14/C-morphine HCl as a tracer. The results show that the stem latex, as well, contains considerable amounts of alkaloids and that the stems may well play an important role in alkaloid production, in the country.

  18. Suitability of Natural Rubber Latex and Waste Foundry Sand in Cement Concrete

    OpenAIRE

    Samuel Idiculla Thomas; Nabil Hossiney; Arjun H R; Beulah. M

    2016-01-01

    Suitability of Natural Rubber Latex (NRL) as an additive and Waste Foundry Sand (WFS) as partial replacement to river sand, in cement concrete was investigated. Experimental study was performed with concrete mixtures containing 1% latex to water ratio, along with 5% and 10% replacement of river sand by WFS. Properties of concrete were studied in both fresh and hardened state. The results of laboratory tests indicate that WFS and NRL reduces the workability of concrete. Slight reduction in ...

  19. Synthesis and applications of MANs/poly(MMA-co-BA) nanocomposite latex by miniemulsion polymerization

    OpenAIRE

    Gong, Sheng; Chen, Huayao; Zhou, Xinhua; Gunasekaran, Sundaram

    2017-01-01

    We have synthesized core-shell structured 3-methacryloxypropyltrimethoxysilane (MPS) functionalized antimony-doped tin oxide nanoparticles (MANs)–poly(methyl methacrylate-co-butyl acrylate) (PMMA-co-BA, PMB) nanocomposite latex particles via miniemulsion polymerization method. Polymerizable anionic surfactant DNS-86 (allyloxy polyoxyethylene(10) nonyl ammonium sulfate) was first introduced to synthesize core-shell nanocomposite. The morphologies of synthesized MANs and MANs/PMB latex nanocomp...

  20. Diagnostic value of the ISAC(®) allergy chip in detecting latex sensitizations.

    Science.gov (United States)

    Seyfarth, Florian; Schliemann, Sibylle; Wiegand, Cornelia; Hipler, Uta-Christina; Elsner, Peter

    2014-01-01

    Latex allergy can be diagnosed by different test methods such as IgE quantification, Western blot, cellular antigen stimulation test (CAST), and in vivo methods [e.g. skin prick test (SPT)]. Phadia provides two modern methods using recombinant latex allergens: ImmunoCAP(®) and the Immuno Solid-phase Allergen Chip (ISAC(®)), which enables simultaneous determination of specific IgE against five latex allergens. We compared the diagnostic sensitivity of the ISAC(®) test kit and the conventional Hev b 5-spiked ImmunoCAP(®) latex extract. Forty sera were sampled from subjects with suspected natural rubber latex (NRL) allergy. These patients had positive SPT to NRL extract, positive NRL Western blots, and positive results in the CAST. All sera were analysed using the ISAC(®) and recombinant NRL ImmunoCAP(®) allergens and compared to the results of 20 negative control sera. Only 22 of the 40 subjects (55 %) showed positivity to at least one latex allergen on the ISAC(®) (sensitivity ISAC(®) 55 %). The sensitivity of the ImmunoCAP(®) latex extract was 70 %. The most frequently detected sensitization was against Hev b 6.01 (n = 12). When the serum samples were tested with all recombinant ImmunoCAP(®) allergens, three additional sensitizations against latex could be detected compared to the ISAC(®). Microarrays do offer many potential benefits such as elegant simultaneous determination of sensitizations against different NRL allergens with minimal amounts of serum. However, a negative NRL test result should be regarded with caution and at least be confirmed by other in vitro methods.

  1. 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...

  2. 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.

  3. 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.

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

    Science.gov (United States)

    Shivkar, Yatin M; Kumar, Vijay L

    2003-01-01

    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. METHODS: Inflammation was induced in the hind paw of rats by injecting different doses of dried latex (DL) of C. procera. The inhibitory effect of phenylbutazone, dexamethasone, celecoxib, cyproheptadine, chlorpheniramine and compound 48/80 on edema volume was evaluated and compared with that against carrageenan. The histamine content of DL was measured fluorometrically. RESULTS: DL produced dose-dependent inflammation of the rat paw. Cyproheptadine and chlorpheniramine effectively inhibited DL-induced inflammation (90%; p procera latex-induced inflammation and antihistaminic drugs could be effectively used to inhibit inflammatory response elicited by exposure to latex. PMID:14760937

  5. Physical Methods for the Preparation of Hybrid Nanocomposite Polymer Latex Particles

    Science.gov (United States)

    Teixeira, Roberto F. A.; Bon, Stefan A. F.

    In this chapter, we will highlight conceptual physical approaches towards the fabrication of nanocomposite polymer latexes in which each individual latex particle contains one or more "hard" nanoparticles, such as clays, silicates, titanates, or other metal(oxides). By "physical approaches" we mean that the "hard" nanoparticles are added as pre-existing entities, and are not synthesized in situ as part of the nanocomposite polymer latex fabrication process. We will narrow our discussion to focus on physical methods that rely on the assembly of nanoparticles onto the latex particles after the latex particles have been formed, or its reciprocal analogue, the adhesion of polymer onto an inorganic nanoparticle. First, will discuss the phenomenon of heterocoagulation and its various driving forces, such as electrostatic interactions, the hydrophobic effect, and secondary molecular interactions. We will then address methods that involve assembly of nanoparticles onto or around the more liquid precursors (i.e., swollen/growing latex particles or monomer droplets). We will focus on the phenomenon of Pickering stabilization. We will then discuss features of particle interaction with soft interfaces, and see how the adhesion of particles onto emulsion droplets can be applied in suspension, miniemulsion, and emulsion polymerization. Finally, we will very briefly mention some interesting methods that make use of interface-driven templating for making well-defined assembled clusters and supracolloidal structures.

  6. Contraceptive effectiveness of a polyurethane condom and a latex condom: a randomized controlled trial.

    Science.gov (United States)

    Steiner, Markus J; Dominik, Rosalie; Rountree, R Wesley; Nanda, Kavita; Dorflinger, Laneta J

    2003-03-01

    To compare the contraceptive effectivenesses of a polyurethane condom and a standard latex condom. Secondary outcomes of interest were safety, functionality, discontinuation, and acceptability. We randomized 901 couples to use either the polyurethane condom or a standard latex condom as their only form of contraception. We tested for pregnancy at enrollment and at every scheduled follow-up visit (weeks 4, 10, 16, 22, and 30). The 6-month typical-use pregnancy probabilities were 9.0% (95% confidence interval [CI] 5.9, 12.2) for the polyurethane group and 5.4% (95% CI 2.9, 7.8) for the latex group; the hazard ratio was 1.7 (95% CI 1.1, 2.7), and we failed to reject the null hypothesis of our test of noninferiority. Females in the polyurethane group reported fewer genital irritations (hazard ratio 0.6; 95% CI 0.5, 0.8; P effective as the latex comparator condom for pregnancy prevention. However, the risk of pregnancy in the polyurethane group falls in the range of other barrier methods. For people with latex sensitivity or who find latex condoms unacceptable, this polyurethane condom represents one of several synthetic male condom alternatives currently available on the US market.

  7. 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.

  8. Differential expression of mitochondrial pyruvate dehydrogenase gene correlates with latex yield and tapping in rubber tree

    Directory of Open Access Journals (Sweden)

    Paweena CHUENWARIN

    2016-11-01

    Full Text Available Natural rubber (cis-1,4-polyisoprene is a product of the isoprenoid biosynthesis pathway which requires an allylic pyrophosphate and isopentenyl pyrophosphate (IPP to initiate and elongate the rubber molecule. The biosynthesis of IPP occurs via two distinct routes: the mevalonate (MVA and methylerythritol phosphate (MEP pathways. In this study, the expression of 34 genes related to rubber biosynthesis were compared between high and low latex yielding trees of two rubber tree clones, PB 217 and PB 260. Almost all tested genes revealed no significantly differential expression related to latex yield. Only mitochondrial pyruvate dehydrogenase (PDCE1 showed specific up-regulation in the high latex yielding trees of both tested clones. Interestingly, the expression of PDCE1 involving in the production of acetyl-CoA in mitochondria was also significantly induced by latex loss upon tapping. The increasing of acetyl-CoA and energy production may favor rubber tree to produce more latex. The in silico analysis showed that HbPDCE1 promoter contained ethylene and copper-responsive elements. Ethylene is worldwide used rubber stimulant while copper sulfate was also reported to be able to stimulate the latex yield. This suggested that HbPDCE1 may be transcriptionally regulated by these two compounds however the in vivo regulation of this gene should be further investigated.

  9. Characterisation of general proteolytic, milk clotting and antifungal activity of Ficus carica latex during fruit ripening.

    Science.gov (United States)

    Raskovic, Brankica; Lazic, Jelena; Polovic, Natalija

    2016-01-30

    The physiological role of fig latex is to protect the plant from pathogens. Latex is a rich source of proteases, predominantly ficin. Fig latex also contains collagenolytic protease and chitinolytic enzymes. Our aim was to investigate changes in protein composition, enzyme and antifungal activities of fig latex during fruit ripening. Comparison of latex samples in different time periods showed a uniform increase of protein concentration in chronological order. The content of collagenolytic protease did not differ significantly in the latex samples, while the content of ficin decreased. Ficin-specific activity towards casein was the highest at the beginning of fruit development (about 80 U mg(-1)). Specific milk clotting activity increased as well as the abundance of casein band in the clots. Specific chitinolytic activity at the beginning of flowering was 6.5 times higher than the activity in the period when fruits are ripe. Antifungal activity is the most extensive in spring. Ficin forms with different casein specificities are present in different proportions during fruit ripening, which is of importance for applications in the dairy industry. The protection mechanism against insects and fungi, which relies on chitinolytic activity, is the most important in the early phases of flowering and is replaced with other strategies over time. © 2015 Society of Chemical Industry.

  10. 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. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. The Effect of Biduri (Calotropis gigantean) Latex on Meat Quality of Post Laying Hen

    Science.gov (United States)

    Nuhriawangsa, A. M. P.; Swastike, W.; Hertanto, B. S.; W, A.; Pradisha, E. D.

    2017-04-01

    The aim of this research was to investigate the effect of biduri (Calotropis gigantean) latex treatment on physical quality and hedonic test of meat of post laying hen. Samples of this research used meat of post laying hen strain Lohman aged 90 weeks. Thigh muscle was used for physical quality and breast muscle for hedonic test. Extract of biduri latex were obtained by cutting and tapping of young stem tissue, and it was centrifuged to obtain crude fluid of biduri latex (supernatant). Variables of this research were pH, cooking loss, tenderness, and water holding capacity (WHC), and hedonic test. Levels of biduri latex were 0, 3, 6 and 9% were measured from weight of the samples and the treatment of biduri latex by smearing on the surface of meat samples. The experimental design of the research used one way randomized design. The data was analyzed by using ANOVA, and differences between treatment means were further analysed using Duncan’s New Multiple Range Test. The effect of biduri latex did not affect on pH, but it significantly affected on cooking loss, WHC, tenderness, and hedonic test (platex with concentration of 3% could increase meat quality of meat of post laying hen.

  12. A major latex-like protein is a key factor in crop contamination by persistent organic pollutants.

    Science.gov (United States)

    Inui, Hideyuki; Sawada, Mami; Goto, Junya; Yamazaki, Kiyoshi; Kodama, Noriko; Tsuruta, Hiroki; Eun, Heesoo

    2013-04-01

    This is the first report, to our knowledge, to reveal important factors by which members of the Cucurbitaceae family, such as cucumber (Cucumis sativus), watermelon (Citrullus lanatus), melon (Cucumis melo), pumpkin (Cucurbita pepo), squash (C. pepo), and zucchini (C. pepo), are selectively polluted with highly toxic hydrophobic contaminants, including organochlorine insecticides and dioxins. Xylem sap of C. pepo ssp. pepo, which is a high accumulator of hydrophobic compounds, solubilized the hydrophobic compound pyrene into the aqueous phase via some protein(s). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of xylem sap of two C. pepo subspecies revealed that the amount of 17-kD proteins in C. pepo ssp. pepo was larger than that in C. pepo ssp. ovifera, a low accumulator, suggesting that these proteins may be related to the translocation of hydrophobic compounds. The protein bands at 17 kD contained major latex-like proteins (MLPs), and the corresponding genes MLP-PG1, MLP-GR1, and MLP-GR3 were cloned from the C. pepo cultivars Patty Green and Gold Rush. Expression of the MLP-GR3 gene in C. pepo cultivars was positively correlated with the band intensity of 17-kD proteins and bioconcentration factors toward dioxins and dioxin-like compounds. Recombinant MLP-GR3 bound polychlorinated biphenyls immobilized on magnetic beads, whereas recombinant MLP-PG1 and MLP-GR1 did not. These results indicate that the high expression of MLP-GR3 in C. pepo ssp. pepo plants and the existence of MLP-GR3 in their xylem sap are related to the efficient translocation of hydrophobic contaminants. These findings should be useful for decreasing the contamination of fruit of the Cucurbitaceae family as well as the phytoremediation of hydrophobic contaminants.

  13. A Pneumatic Actuated Microfluidic Beads-Trapping Device

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-08-20

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

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

    Science.gov (United States)

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

    2010-07-01

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

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

    CERN Document Server

    Dutta, Shovan

    2012-01-01

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

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

    Science.gov (United States)

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

    2016-08-30

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

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

    Science.gov (United States)

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

    2007-12-01

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

  18. Latex Imaging by Environmental STEM: Application to the Study of the Surfactant Outcome in Hybrid Alkyd/Acrylate Systems

    OpenAIRE

    Faucheu, Jenny; Chazeau, Laurent; Gauthier, Catherine; Cavaille, Jean-Yves; Goikoetxea, Monika; Minari, Roque; Asua, Jose M.

    2009-01-01

    International audience; Among other uses. latexes are a successful alternative to solvent-borne binders for coatings. Efforts are made to produce hybrid nanostructured latexes containing an acrylic phase and an alkyd phase, However, after the film-forming process, the surfactant used to stabilize these latexes remains in the film, and its location can have a drastic effect on the application properties. Among the processing parameters, the alkyd hydrophobicity can strongly influence this loca...

  19. Latex imaging by environmental STEM: application to the study of the surfactant outcome in hybrid alkyd/acrylate systems.

    Science.gov (United States)

    Faucheu, Jenny; Chazeau, Laurent; Gauthier, Catherine; Cavaillé, Jean-Yves; Goikoetxea, Monika; Minari, Roque; Asua, José M

    2009-09-01

    Among other uses, latexes are a successful alternative to solvent-borne binders for coatings. Efforts are made to produce hybrid nanostructured latexes containing an acrylic phase and an alkyd phase. However, after the film-forming process, the surfactant used to stabilize these latexes remains in the film, and its location can have a drastic effect on the application properties. Among the processing parameters, the alkyd hydrophobicity can strongly influence this location. This article aims at the imaging of these surfactant molecules in two hybrid latexes with different hydrophobicity level of the alkyd resin. A first part of this paper is dedicated to the understanding of the contrast provided by the surfactant in environmental STEM imaging of latexes. Then, the influence of surfactant-polymer affinity on the surfactant location after film-forming of those hybrid alkyd/acrylate latexes is studied by this technique. It is shown that in the hybrid latex with an alkyd shell (obtained with the most hydrophilic resin), the surfactant molecules tend to remain buried in the alkyd phase. Conversely, in the hybrid latex with an acrylate shell (in the case of the most hydrophobic resin), the surfactant molecules tend to gather into islands like in pure acrylate latex films.

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

    OpenAIRE

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

    2001-01-01

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

  1. Synthesis and characterization of polymer-silica hybrid latexes and sol-gel-derived films

    Energy Technology Data Exchange (ETDEWEB)

    Petcu, Cristian; Purcar, Violeta [National Research-Development Institute for Chemistry and Petrochemistry-ICECHIM, Polymer Department, Splaiul Independentei 202, 6th district, 060021, Bucharest (Romania); Ianchiş, Raluca, E-mail: ralumoc@yahoo.com [National Research-Development Institute for Chemistry and Petrochemistry-ICECHIM, Polymer Department, Splaiul Independentei 202, 6th district, 060021, Bucharest (Romania); Spătaru, Cătălin-Ilie; Ghiurea, Marius; Nicolae, Cristian Andi [National Research-Development Institute for Chemistry and Petrochemistry-ICECHIM, Polymer Department, Splaiul Independentei 202, 6th district, 060021, Bucharest (Romania); Stroescu, Hermine [Institute of Physical Chemistry “Ilie Murgulescu” of the Romanian Academy, Splaiul Independentei 202, 060021, Bucharest (Romania); Atanase, Leonard-Ionuţ [University Apollonia, “Acad. Ioan Haulica” Research Institute, Iasi (Romania); Frone, Adriana Nicoleta; Trică, Bogdan; Donescu, Dan [National Research-Development Institute for Chemistry and Petrochemistry-ICECHIM, Polymer Department, Splaiul Independentei 202, 6th district, 060021, Bucharest (Romania)

    2016-12-15

    Highlights: • Si-based polymer is distributed onto the silica surface of sol-gel hybrid films. • FT-IR spectra of sol-gel derived materials confirmed the different chemical structure. • Hydrophobicity increased due to the increasing number of alkyl groups attached to the surface. - Abstract: Sol-gel derived organic-inorganic hybrid systems were obtained by applying alkaline-catalyzed co-hydrolysis and copolycondensation reactions of tetraethoxysilane (TEOS), methyltriethoxysilane (MTES), isobutyltriethoxysilane (IBTES), diethoxydimethylsilane (DMDES), and vinyltriethoxysilane (VTES), respectively, into a polymer latex functionalized with vinyltriethoxysilane (VTES). The properties of the latex hybrid materials were analyzed by FTIR, water contact angle, environmental scanning electron microscopy (ESEM), TEM and AFM analysis, respectively. FT-IR spectra confirmed that the chemical structures of the sol-gel derived organic-inorganic materials are changed as function of inorganic precursor and Si−O−Si networks are formed during the co-hydrolysis and copolycondensation reactions. The water contact angle on the sol-gel latex film containing TEOS + VTES increased to 135° ± 2 compared to 65° ± 5 for the blank latex, due VTES incorporation into latex material. TGA curves of hybrid sample modifies against neat polymer, the thermal stability being influenced by the presence of the inorganic partner. ESEM analysis showed that the latex hybrid films prepared with different inorganic precursors were formed and the Si-based polymers were distributed on the surface of the dried sol-gel hybrid films. TEM and AFM photos revealed that the latex emulsion morphology was modified due to the VTES incorporation into system.

  2. Cross-reactivity between Ficus benjamina latex and fig fruit in patients with clinical fig allergy.

    Science.gov (United States)

    Focke, M; Hemmer, W; Wöhrl, S; Götz, M; Jarisch, R

    2003-07-01

    Anaphylactic reactions to fig fruits (Ficus carica) have been reported from subjects sensitized to Ficus benjamina (FB) latex allergens. Figs may also be involved in the latex-fruit syndrome. To study the immunologic relationship between fig fruit, Ficus benjamina, natural rubber latex (Hevea brasiliensis), and other tropical fruits. RAST inhibition and Western blotting with FB and fruit extracts was performed in five patients with oral allergy syndrome (OAS) or anaphylaxis after the ingestion of figs and one patient with symptoms from exposure to FB trees. Co-sensitization to rubber latex and tropical fruits (kiwi, banana, avocado, papaya, pineapple, mulberry) was studied by skin testing. RAST to FB was inhibited >95% by FB extracts and 16-65% (mean 49%) by extracts from fresh fig. RAST to fig fruit was inhibited >95% by FB and fresh fig, 63-97% (mean 86%) by dried fig, and 0-84% (mean 35.5%) by kiwi fruit. FB and fig extracts lost most of their allergenicity when denatured by heat (95 degrees C) or reduced by dithiothreitol. Western blotting after non-reducing gel electrophoresis revealed IgE binding to proteins of 22 and 28-34 kDa in FB latex; however, no corresponding allergens could be detected in fig extracts. Positive skin tests were obtained most often with kiwi fruit, papaya, and avocado. Sensitization to rubber latex could not be demonstrated in any of the patients. RAST to papain was positive in three of five patients. Allergic reactions to fresh or dried figs can present as a consequence of primary sensitization to airborne FB allergens independent of sensitization to rubber latex allergens. Kiwi fruit, papaya, and avocado as well as pineapple and banana may be other fruits associated with sensitization to Ficus allergens.

  3. [Usefulness of a questionnaire and RAST in screening of health care workers allergic to latex].

    Science.gov (United States)

    Copertaro, A; Bracci, M; Barbaresi, Mariella; Bianchini, G

    2006-01-01

    The prevalence of latex mediated IgE allergy in health care workers varies, according to the various studies, from 0.5% to 16. 7%. The onset of latex allergy involves aspects concerning the worker's health, the need for job transfer and possible retraining. In any case, the use of latex gloves in health care environments cannot be discarded, since they offer more efficacious protection from biological agents, compared to gloves of different materials. Our objectives were to verify the prevalence of latex allergy in a sample of 515 health care workers and evaluate the usefulness of RAST and a questionnaire especially organized to identify potentially allergic subjects, at the same time limiting the number of false positive and false negative results. 515 health care workers of the ASUR Zone7-Ancona local health unit accepted to answer to a questionnaire and to undergo a RAST testfor latex. Those with positive responses to the questionnaire or to RAST were later invited to undergo further allergological tests (prick and prick by prick). The questionnaire was revised according to the results obtained, thus increasing its positive predictiveness. Prevalence of latex allergy in our sample was 1, 7%, positive predictiveness of RAST was rather low (31.3%), but increased considerably if combined with the modified questionnaire (62.5%). The Prick by Prick test gave more specific results than the Prick test. The proposed questionnaire can reduce the number of false positive workers needing to undergo further allergological tests and may be usefully applied in the screening of latex mediated IgE allergy in health care workers.

  4. Changes in chemical permeation of disposable latex, nitrile, and vinyl gloves exposed to simulated movement.

    Science.gov (United States)

    Phalen, Robert N; Le, Thi; Wong, Weng Kee

    2014-01-01

    Glove movement can affect chemical permeation of organic compounds through polymer glove products. However, conflicting reports make it difficult to compare the effects of movement on chemical permeation through commonly available glove types. The aim of this study was to evaluate the effect of movement on chemical permeation of an organic solvent through disposable latex, nitrile, and vinyl gloves. Simulated whole-glove permeation testing was conducted using ethyl alcohol and a previously designed permeation test system. With exposure to movement, a significant decrease (p ≤ 0.001) in breakthrough time (BT) was observed for the latex (-23%) and nitrile gloves (-31%). With exposure to movement, only the nitrile glove exhibited a significant increase (p ≤ 0.001) in steady-state permeation rate (+47%) and cumulative permeation at 30 min (+111%). Even though the nitrile glove provided optimum chemical resistance against ethyl alcohol, it was most affected by movement. With exposure to movement, the latex glove was an equivalent option for overall worker protection, because it was less affected by movement and the permeation rate was lower than that of the nitrile glove. In contrast, the vinyl glove was the least affected by movement, but did not provide adequate chemical resistance to ethyl alcohol in comparison with the nitrile and latex gloves. Glove selection should take movement and polymer type into account. Some glove polymer types are less affected by movement, most notably the latex glove in this test. With nitrile gloves, at least a factor of three should be used when attempting to assign a protection factor when repetitive hand motions are anticipated. Ultimately, the latex gloves outperformed nitrile and vinyl in these tests, which evaluated the effect of movement on chemical permeation. Future research should aim to resolve some of the observed discrepancies in test results with latex and vinyl gloves.

  5. Rapid diagnosis of bacterial meningitis by latex agglutination test.

    Science.gov (United States)

    Abdel-Ghani, S M; Hassan, E M; Masoud, S; Guirgis, N I

    1989-01-01

    Forty-three patients admitted to Abassia Fever Hospital suffering from meningitis were studied. They were 27 male and 16 female and divided into 3 age groups, as a control, 4 normal CSF samples were collected. A sterile CSF was collected and examined for pressure, aspect, glucose, protein and cellular content. Although all these tests were helpful in differentiating the type of meningitis, a remarkable overlap between the results were detected. Bacteriological study of CSF showed that bacterial culture was more sensitive than the Gram-stained film in (80% and 72% respectively) (p less than 0.05). However, it is a time consuming and its results greatly affected by prior uses of antibiotics. Also the antigen of N. meningitidis A & C, H. influenzae and S. pneumoniae were detected by latex agglutination (L.A.) and gave positive results in 76% of cases. It was less sensitive than the culture method. As a conclusion, L.A. test is a rapid and simple method of diagnosis of bacterial meningitis which give immediate information to the clinician. The sensitivity and specificity of L.A. can be greatly improved by using a higher quality of antibody for all serotypes in the locality.

  6. On the release of metronidazole from natural rubber latex membranes

    Energy Technology Data Exchange (ETDEWEB)

    Herculano, Rondinelli D., E-mail: rond@assis.unesp.br [Departamento de Ciencias Biologicas - Faculdade de Ciencias e Letras de Assis-Universidade Estadual Paulista, Av. Dom Antonio, 2100, Zip Code: 19806-900, Assis, SP (Brazil); Alencar de Queiroz, Alvaro A. [Departamento de Fisica e Quimica-Universidade Federal de Itajuba, Itajuba, MG (Brazil); Kinoshita, Angela [Universidade do Sagrado Coracao-Rua Irma Arminda, 10-50, Bauru, SP (Brazil); Oliveira, Osvaldo N. [Instituto de Fisica de Sao Carlos-Universidade de Sao Paulo, Sao Carlos, SP (Brazil); Graeff, Carlos F.O. [Departamento de Fisica - FC - Universidade Estadual Paulista, Bauru, SP (Brazil)

    2011-03-12

    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.

  7. Latex micro-balloon pumping in centrifugal microfluidic platforms.

    Science.gov (United States)

    Aeinehvand, Mohammad Mahdi; Ibrahim, Fatimah; Harun, Sulaiman Wadi; Al-Faqheri, Wisam; Thio, Tzer Hwai Gilbert; Kazemzadeh, Amin; Madou, Marc

    2014-03-07

    Centrifugal microfluidic platforms have emerged as point-of-care diagnostic tools. However, the unidirectional nature of the centrifugal force limits the available space for multi-step processes on a single microfluidic disc. To overcome this limitation, a passive pneumatic pumping method actuated at high rotational speeds has been previously proposed to pump liquid against the centrifugal force. In this paper, a novel micro-balloon pumping method that relies on elastic energy stored in a latex membrane is introduced. It operates at low rotational speeds and pumps a larger volume of liquid towards the centre of the disc. Two different micro-balloon pumping mechanisms have been designed to study the pump performance at a range of rotational frequencies from 0 to 1500 rpm. The behaviour of the micro-balloon pump on the centrifugal microfluidic platforms has been theoretically analysed and compared with the experimental data. The experimental data show that the developed pumping method dramatically decreases the required rotational speed to pump liquid compared to the previously developed pneumatic pumping methods. It also shows that within a range of rotational speed, a desirable volume of liquid can be stored and pumped by adjusting the size of the micro-balloon.

  8. Hormonal treatment of the bark of rubber trees (Hevea brasiliensis) increases latex yield through latex dilution in relation with the differential expression of two aquaporin genes.

    Science.gov (United States)

    Tungngoen, Kessarin; Viboonjun, Unchera; Kongsawadworakul, Panida; Katsuhara, Maki; Julien, Jean-Louis; Sakr, Soulaiman; Chrestin, Hervé; Narangajavana, Jarunya

    2011-02-15

    Natural rubber is synthesized in laticifers in the inner liber of the rubber tree (Hevea brasiliensis). Upon bark tapping, the latex is expelled due to liber turgor pressure. The mature laticifers are devoid of plasmodesmata; therefore a corresponding decrease in the total latex solid content is likely to occur due to water influx inside the laticifers. Auxins and ethylene used as efficient yield stimulants in mature untapped rubber trees, but, bark treatments with abscisic acid (ABA) and salicylic acid (SA) could also induce a transient increase latex yield. We recently reported that there are three aquaporin genes, HbPIP2;1, HbTIP1;1 and HbPIP1;1, that are regulated differentially after ethylene bark treatment. HbPIP2;1 was up-regulated in both the laticifers and the inner liber tissues, whereas HbTIP1;1 was up-regulated in the latex cells, but very markedly down-regulated in the inner liber tissues. Conversely, HbPIP1;1 was down-regulated in both tissues. In the present study, HbPIP2;1 and HbTIP1;1 showed a similar expression in response to auxin, ABA and SA, as seen in ethylene stimulation, while HbPIP1;1 was slightly regulated by auxin, but neither by ABA nor SA. The analysis of the HbPIP1;1 promoter region indicated the presence of only ethylene and auxin responsive elements. In addition, the poor efficiency of this HbPIP1;1 in increasing plasmalemma water conductance was confirmed in Xenopus oocytes. Thus, an increase in latex yield in response to all of these hormones was proposed to be the major function of aquaporins, HbPIP2;1 and HbTIP1;1. This study emphasized that the circulation of water between the laticifers and their surrounding tissues that result in latex dilution, as well as the probable maintenance of the liber tissues turgor pressure, favor the prolongation of latex flow. Copyright © 2010 Elsevier GmbH. All rights reserved.

  9. 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.

    Science.gov (United States)

    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 expressed in Escherichia coli as fusion proteins with the maltose-binding protein and purified by affinity chromatography. IgE binding to these proteins was studied in sera from 59 latex-allergic patients and 20 banana-allergic patients without latex allergy by ELISA and ELISA inhibition. Additionally, 16,408 allergic patients' sera were tested for IgE binding to hevein, latex chitinase, and wheat germ agglutinin using an allergen microarray. Hevein-specific IgE was detected in 34/59 (58%) latex-allergic patients' sera. HLDs of latex, banana, and avocado chitinases were recognized by 21 (36%), 20 (34%), and 9 (15%) sera, respectively. In contrast, only one of 20 banana-allergic patients without latex allergy was sensitized to chitinase HLDs. In most tested latex-allergic patients' sera, IgE binding to hevein was only partially reduced by preincubation with HLDs. Among hevein-sensitized, latex-allergic patients, the percentage of plant food allergy (15/34 = 44%) was equal to latex-allergic patients without hevein sensitization (11/25 = 44%). In the general allergic population, 230 of 16,408 sera (1.4%) reacted to hevein and/or a hevein-like allergen. Of these, 128 sera showed an isolated sensitization to hevein, whereas only 17 bound to latex chitinase or wheat germ agglutinin without hevein sensitization. In conclusion, the IgE response to HLDs is elicited by hevein as sensitizing allergen in most cases. Despite considerable cross-reactivity between these allergens, no correlation

  10. 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

    Science.gov (United States)

    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 expressed in Escherichia coli as fusion proteins with the maltose-binding protein and purified by affinity chromatography. IgE binding to these proteins was studied in sera from 59 latex-allergic patients and 20 banana-allergic patients without latex allergy by ELISA and ELISA inhibition. Additionally, 16,408 allergic patients’ sera were tested for IgE binding to hevein, latex chitinase, and wheat germ agglutinin using an allergen microarray. Hevein-specific IgE was detected in 34/59 (58%) latex-allergic patients’ sera. HLDs of latex, banana, and avocado chitinases were recognized by 21 (36%), 20 (34%), and 9 (15%) sera, respectively. In contrast, only one of 20 banana-allergic patients without latex allergy was sensitized to chitinase HLDs. In most tested latex-allergic patients’ sera, IgE binding to hevein was only partially reduced by preincubation with HLDs. Among hevein-sensitized, latex-allergic patients, the percentage of plant food allergy (15/34 = 44%) was equal to latex-allergic patients without hevein sensitization (11/25 = 44%). In the general allergic population, 230 of 16,408 sera (1.4%) reacted to hevein and/or a hevein-like allergen. Of these, 128 sera showed an isolated sensitization to hevein, whereas only 17 bound to latex chitinase or wheat germ agglutinin without hevein sensitization. In conclusion, the IgE response to HLDs is elicited by hevein as sensitizing allergen in most cases. Despite considerable cross-reactivity between these allergens, no

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

    African Journals Online (AJOL)

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

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

    Science.gov (United States)

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

    2012-01-01

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

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

    Science.gov (United States)

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

    2014-09-08

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

  14. Removal of organic dyes by magnetic alginate beads.

    Science.gov (United States)

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

    2008-02-01

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

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

    African Journals Online (AJOL)

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

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

    African Journals Online (AJOL)

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

  17. Magnetic manipulation and sensing of beads for bioapplications

    DEFF Research Database (Denmark)

    Henriksen, Anders Dahl

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

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

    African Journals Online (AJOL)

    Exploring traditional glass bead making techniques in jewellery in some prominent areas in Ghana is a means to exposing the area for metal and ceramic artists and other related fields of discipline such as aesthetics and criticism to complement their form of art for a better livelihood and diversification in jewellery. There are ...

  19. exploring traditional glass bead making techniques in jewellery

    African Journals Online (AJOL)

    User

    ABSTRACT. Exploring traditional glass bead making techniques in jewellery in some prominent areas in. Ghana is a means to exposing the area for metal and ceramic artists and other related fields of discipline such as aesthetics and criticism to complement their form of art for a better livelihood and diversification in ...

  20. Glass bead transformation method for gram-positive bacteria

    OpenAIRE

    Pongsak Rattanachaikunsopon; Parichat Phumkhachorn

    2009-01-01

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

  1. Chitosan-Based Nanocomposite Beads for Drinking Water Production

    Science.gov (United States)

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

    2017-05-01

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

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

    African Journals Online (AJOL)

    user

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

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

    Science.gov (United States)

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

    2015-07-08

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

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

    Indian Academy of Sciences (India)

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

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

    Science.gov (United States)

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

    2014-01-01

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

  6. EXFOLIATION AT WIRE TWISTING FOR TIRES BEAD RINGS

    Directory of Open Access Journals (Sweden)

    A. N. Savenok

    2010-01-01

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

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

    OpenAIRE

    ADR Madjid; M Nitsae; Atikah Atikah; A Sabarudin

    2016-01-01

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

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

    NARCIS (Netherlands)

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

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

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

    Science.gov (United States)

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

    2014-12-04

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1978-10-01

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

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

    Science.gov (United States)

    Beehler, J W; DeFoliart, G R

    1991-06-01

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

  12. Antimicrobial and anti-inflammatory activities, wound-healing effectiveness and chemical characterization of the latex of Jatropha neopauciflora Pax.

    Science.gov (United States)

    Hernandez-Hernandez, A B; Alarcon-Aguilar, F J; Almanza-Perez, J C; Nieto-Yañez, O; Olivares-Sanchez, J M; Duran-Diaz, A; Rodriguez-Monroy, M A; Canales-Martinez, M M

    2017-05-23

    Jatropha neopauciflora Pax is an endemic species to Mexico, and its latex is used in traditional medicine to treat mouth infections when there are loose teeth and to heal wounds. In this research, we evaluated the antimicrobial activity, wound healing efficacy and chemical characterization of J. neopauciflora latex in a murine model. The antibacterial activity was determined using Gram positive and negative strains, the antifungal activity was determined using yeast and filamentous fungi, and the wound healing efficacy of the latex was determined using the tensiometric method. The anti-inflammatory activity was evaluated using the plantar oedema model in rats, administering the latex orally and topically. Cytotoxic activity was determined in vitro in two different cell lines. Antioxidant capacity, total phenolics, total flavonoids, reducing carbohydrates and latex proteins were quantified. The latex analysis was performed by High Performance Liquid Chromatography (HPLC). Finally, molecular exclusion chromatography was performed. The latex demonstrated antibacterial activity. The most sensitive strains were Gram positive bacteria, particularly S. aureus (MIC=2mg/mL), and the latex had bacteriostatic activity. The latex did not show antifungal activity. The latex demonstrated a wound-healing efficacy, even the positive control (Recoveron). The orally administered latex demonstrated the best anti-inflammatory activity and was not toxic to either of the 2 cell lines. The latex had a high antioxidant capacity (SA 50 =5.4µg/mL), directly related to the total phenolic (6.9mg GAE/mL) and flavonoid (12.53µg QE/mL) concentration. The carbohydrate concentration was 18.52µg/mL, and fructose was the most abundantly expressed carbohydrate in the latex (14.63µg/mL, 79.03%). Additionally, the latex contained proteins (7.62µg/mL) in its chemical constitution. As secondary metabolites, the HPLC analysis indicated the presence of phenols and flavonoids. The J. neopauciflora

  13. Conventional rapid latex agglutination in estimation of von Willebrand factor: method revisited and potential clinical applications.

    Science.gov (United States)

    Mahat, Marianor; Abdullah, Wan Zaidah; Hussin, Che Maraina Che

    2014-01-01

    Measurement of von Willebrand factor antigen (VWF : Ag) levels is usually performed in a specialised laboratory which limits its application in routine clinical practice. So far, no commercial rapid test kit is available for VWF : Ag estimation. This paper discusses the technical aspect of latex agglutination method which was established to suit the purpose of estimating von Willebrand factor (VWF) levels in the plasma sample. The latex agglutination test can be performed qualitatively and semiquantitatively. Reproducibility, stability, linearity, limit of detection, interference, and method comparison studies were conducted to evaluate the performance of this test. Semiquantitative latex agglutination test was strongly correlated with the reference immunoturbidimetric assay (Spearman's rho = 0.946, P agglutination test and the reference assay. Using the scoring system for the rapid latex test, no agglutination is with 0% VWF : Ag (control negative), 1+ reaction is equivalent to 150% VWF : Ag (when comparing with immunoturbidimetric assay). The findings from evaluation studies suggest that latex agglutination method is suitable to be used as a rapid test kit for the estimation of VWF : Ag levels in various clinical conditions associated with high levels and low levels of VWF : Ag.

  14. Labbtex: Toolbox para generación de informes en LATEX para Matlab

    Directory of Open Access Journals (Sweden)

    José Luis Almazán Gárate

    2012-10-01

    Full Text Available En este artículo se presenta el software desarrollado por el Equipo H3lite dentro del Departamento de Ingeneniería Civil. Transportes de la Escuela de Ingenieros de Caminos, Canales y Puertos de la Universidad Politécnica de Madrid para la generación de informes enLATEX mediante el software Matlab® y la integración en sus rutinas, Labbtex.La librería Labbtex proporciona un marco flexible para mezclar texto y código Matlab® para la generación automática de documentos. Un rchivo fuente simple contiene el texto de documentación y el código Matlab, al correr la aplicación se genera un documento final LATEX que contiene el texto, gráficos y tablas indicados con el formato de un documento LATEX. El código Matlab genera un documento LATEX usando la sintaxis. Así, LATEX (para composición de texto de alta calidad y Matlab® (para cálculo matemático pueden usarse simultáneamente. Esto permite la generación de informes en tiempo real con un uso de recursos mínimo.

  15. New hybrid latexes from a soybean oil-based waterborne polyurethane and acrylics via emulsion polymerization.

    Science.gov (United States)

    Lu, Yongshang; Larock, Richard C

    2007-10-01

    A series of new waterborne polyurethane (PU)/acrylic hybrid latexes have been successfully synthesized by the emulsion polymerization of acrylic monomers (butyl acrylate and methyl methacrylate) in the presence of a soybean oil-based waterborne PU dispersion using potassium persulfate as an initiator. The waterborne PU dispersion has been synthesized by a polyaddition reaction of toluene 2,4-diisocyanate and a soybean oil-based polyol (SOL). The resulting hybrid latexes, containing 15-60 wt % SOL as a renewable resource, are very stable and exhibit uniform particle sizes of 125 +/- 20 nm as determined by transmittance electronic microscopy. The structure, thermal, and mechanical properties of the resulting hybrid latex films have been investigated by Fourier transform infrared spectroscopy, solid state 13C NMR spectroscopy, dynamic mechanical analysis, extraction, and mechanical testing. Grafting copolymerization of the acrylic monomers onto the PU network occurs during the emulsion polymerization, leading to a significant increase in the thermal and mechanical properties of the resulting hybrid latexes. This work provides a new way of utilizing renewable resources to prepare environmentally friendly hybrid latexes with high performance for coating applications.

  16. Influence of SBR latex and HPMC on the cement hydration at early age

    Directory of Open Access Journals (Sweden)

    Xiaoling Qu

    2017-06-01

    Full Text Available A study was carried out, using heat flow calorimetry, XRD, FTIR and SEM imaging analysis, of different influences which were exerted by the type of polymer, on the hydration behaviors of cement pastes. It is shown that both styrene-butadiene rubber latex (SBR latex and hydroxypropylmethyl cellulose (HPMC can cut down the cement hydration heat evolution rate and total heat between 5 h and 20 h. The former has a weaker influence but can play a positive role in enhancing the latter. XRD and FTIR analysis show that SBR latex and HPMC have played a negative role on the contents of Ca(OH2 in cement pastes cured for 24 h, and there is a relationship of mutual promotion between SBR latex and HPMC in terms of inhibiting the formation and growth of Ca(OH2, but this inhibiting effect becomes weaker at 72 h. HPMC has the superior inhibiting effect owing to its special OH groups compared to SBR latex.

  17. Validation of reference genes for quantitative real-time PCR during latex regeneration in rubber tree.

    Science.gov (United States)

    Long, Xiangyu; He, Bin; Gao, Xinsheng; Qin, Yunxia; Yang, Jianghua; Fang, Yongjun; Qi, Jiyan; Tang, Chaorong

    2015-06-01

    In rubber tree, latex regeneration is one of the decisive factors influencing the rubber yield, although its molecular regulation is not well known. Quantitative real-time PCR (qPCR) is a popular and powerful tool used to understand the molecular mechanisms of latex regeneration. However, the suitable reference genes required for qPCR are not available to investigate the expressions of target genes during latex regeneration. In this study, 20 candidate reference genes were selected and evaluated for their expression stability across the samples during the process of latex regeneration. All reference genes showed a relatively wide range of the threshold cycle values, and their stability was validated by four different algorithms (comparative delta Ct method, Bestkeeper, NormFinder and GeNorm). Three softwares (comparative delta Ct method, NormFinder and GeNorm) exported similar results that identify UBC4, ADF, UBC2a, eIF2 and ADF4 as the top five suitable references, and 18S as the least suitable one. The application of the screened references would improve accuracy and reliability of gene expression analysis in latex regeneration experiments. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Heterogeneous drying and nonmonotonic contact angle dynamics in concentrated film-forming latex drops

    Science.gov (United States)

    Kumar, Subhalakshmi; Katz, Joshua S.; Schroeder, Charles M.

    2017-11-01

    The dynamic drying process is studied in spatially heterogeneous film-forming latex suspensions across a wide range of dispersion concentrations using optical imaging techniques. Systematic changes in latex suspension concentration are found to affect lateral drying heterogeneity and surface topology. A nonmonotonic decay in contact angle is observed at the edges of drying droplets by continuously monitoring evaporation dynamics, which is quantitatively characterized by the peak strain and peak formation time. An analytical model is developed to explain the nonmonotonic contact-angle decay by considering a transient dilational stress imposed on a viscoelastic solid model for the particle network. Importantly, the latex concentration dependence of this phenomenon provides evidence for a smooth transition from fluid-line pinning to fluid-line recession behavior during drying, leading to ringlike to volcanolike deposition patterns, respectively. Using experimental data for drying heterogeneity, we quantitatively explore the influence of Marangoni flow and capillary pressure on drying behavior. Moreover, our results show that latex concentration and particle packing can also be strategically used to reduce contact-line friction, thereby affecting fluid-line recession. Taken together, these results show that studying latex suspensions in seemingly simple droplet geometries provides insight into the emergent spatially heterogeneous viscoelastic properties during film formation.

  19. The Use of Latex Catheters to Close Enterocutaneous Fistulas: An Institutional Protocol and Retrospective Review.

    Science.gov (United States)

    Young, Shamar; D'Souza, Donna; Hunter, David; Golzarian, Jafar; Rosenberg, Michael

    2017-06-01

    The objective of our study was to retrospectively review an institutional protocol that uses latex catheters for the treatment of enterocutaneous fistulas (ECFs) that are resistant to simple drainage. Forty-six consecutive patients with ECFs that did not close with simple abscess drainage were treated with latex catheters. These patients' charts were retrospectively reviewed to determine treatment success rates and the relationship of treatment success to clinical characteristics. ECFs in 26 of the 46 (56.5%) patients were treated successfully with latex catheters. On univariate analysis, the fistulas that originated from the stomach were statistically less likely to close (p = 0.03), whereas those originating from the small bowel were more likely to close (p = 0.01). The duration of treatment was significantly longer in patients for whom the treatment failed than in those who were successfully treated (p = 0.003). After a total treatment time of more than 116 days (odds ratio [OR], 9.8 [95% CI, 2.5-38.4]; p = 0.001) or latex catheter treatment time of more than 74 days (OR, 8.9 [95% CI, 2.2-35.0]; p = 0.002), the chance of ECF closure decreased significantly. Treatment of ECFs that are resistant to simple abscess cavity drainage with a latex catheter is possible and decreases the need for surgery.

  20. 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

    2015-02-05

    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 in vitro 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. Copyright © 2014 Elsevier B.V. All rights reserved.

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

    NARCIS (Netherlands)

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

    2000-01-01

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

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

    NARCIS (Netherlands)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2017-02-10

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

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

    Directory of Open Access Journals (Sweden)

    Fernando Agua

    2017-05-01

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

  5. FY 2000 Industrial science and technology research and development themes - cooperative project with academic circles. Report on the results of research and development of technologies for creating new bioaffinity molecules using submicron beads (Development of technologies for rational use of energy); 2000 nendo biryushi riyogata seitai ketsugo busshitsu nado sosei gijutsu no kenkyu kaihatsu seika hokokusho. Energy shiyo gorika gijutsu kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    Described herein are the FY 2000 results of the research and development for creating new bioaffinity molecules using submicron beads. The program for development of technology for analyzing chemical-biomolecule complexes using submicron affinity beads has developed a detachable linker which allows the complex, composed of ligand on the affinity latex particle surfaces and receptor bound thereto, to be detached directly from the particles, and also developed the prototype of magnetite-containing polymer particles with a diameter of submicron order, which facilitate recovery of the affinity latex. The program for development of technology to create chemical substances with new functions has successfully constructed the focused library composed of 400 compounds based on the split and pool method for FR225659 as a glucose modulator, chosen as the target material. It also has established the method of synthesizing opioid alkaloid as the target compound on the solid phase, and synthesized 39 opioid compounds with condensed indol rings, having diverse of several substituents. (NEDO)

  6. Preparation and Characterization of Latex Particles as Potential Physical Shale Stabilizer in Water-Based Drilling Fluids

    Directory of Open Access Journals (Sweden)

    Junyi Liu

    2014-01-01

    Full Text Available The poly(styrene-methyl methacrylate latex particles as potential physical shale stabilizer were successfully synthesized with potassium persulfate as an initiator in isopropanol-water medium. The synthesized latex particles were characterized by Fourier transform infrared spectroscopy (FT-IR, particle size distribution measurement (PSD, transmission electron microscopy (TEM, and thermal gravimetric analysis (TGA. FT-IR and TGA analysis confirmed that the latex particles were prepared by polymerization of styrene and methyl methacrylate and maintained good thermal stability. TEM and PSD analysis indicated that the spherical latex particles possessed unimodal distribution from 80 nm to 345 nm with the D90 value of 276 nm. The factors influencing particle size distribution (PSD of latex particles were also discussed in detail. The interaction between latex particles and natural shale cores was investigated quantitatively via pore pressure transmission tests. The results indicated that the latex particles as potential physical shale stabilizer could be deformable to bridge and seal the nanopores and microfractures of shale to reduce the shale permeability and prevent pore pressure transmission. What is more, the latex particles as potential physical shale stabilizer work synergistically with chemical shale stabilizer to impart superior shale stability.

  7. Preliminary study of semi-refined carrageenan (SRC) as secondary gelling agent in natural rubber (NR) latex foam

    Science.gov (United States)

    Norhazariah, S.; Azura, A. R.; Azahari, B.; Sivakumar, R.

    2017-12-01

    Semi-refined carrageenan (SRC) product is considerably cheaper and easier to produce as a natural polysaccharide, which was utilized in food and other product application. However, the application in latex is limited. The aim of this work is to evaluate the SRC produced from low industrial grade seaweed (LIGS) in the latex foam application. The FTIR spectra showed the SRC produced as kappa type carrageenan with lower sulfur content compared to native LIGS. NR latex foam is produced by using the Dunlop method with some modifications. The effect of SRC loading as a secondary gelling agent in NR latex foam is investigated. The density and morphology of the NR latex foam with the addition of the SRC are analyzed. NR latex foam density increased with SRC loading and peaked at 1.8 phr SRC. The addition of SRC has induced the bigger cell size compared to the cell size of the control NR latex foam, as shown in the optical micrograph. It can be concluded that SRC LIGS could be acted as secondary gelling agent in NR latex foam.

  8. Preparation and characterization of latex particles as potential physical shale stabilizer in water-based drilling fluids.

    Science.gov (United States)

    Liu, Junyi; Qiu, Zhengsong; Huang, Wei'an; Song, Dingding; Bao, Dan

    2014-01-01

    The poly(styrene-methyl methacrylate) latex particles as potential physical shale stabilizer were successfully synthesized with potassium persulfate as an initiator in isopropanol-water medium. The synthesized latex particles were characterized by Fourier transform infrared spectroscopy (FT-IR), particle size distribution measurement (PSD), transmission electron microscopy (TEM), and thermal gravimetric analysis (TGA). FT-IR and TGA analysis confirmed that the latex particles were prepared by polymerization of styrene and methyl methacrylate and maintained good thermal stability. TEM and PSD analysis indicated that the spherical latex particles possessed unimodal distribution from 80 nm to 345 nm with the D90 value of 276 nm. The factors influencing particle size distribution (PSD) of latex particles were also discussed in detail. The interaction between latex particles and natural shale cores was investigated quantitatively via pore pressure transmission tests. The results indicated that the latex particles as potential physical shale stabilizer could be deformable to bridge and seal the nanopores and microfractures of shale to reduce the shale permeability and prevent pore pressure transmission. What is more, the latex particles as potential physical shale stabilizer work synergistically with chemical shale stabilizer to impart superior shale stability.

  9. Bacterial community associated with the trunk latex of Hancornia speciosa Gomes (Apocynaceae) grown in the northeast of Brazil.

    Science.gov (United States)

    Silva, Thais Freitas da; Coelho, Marcia Reed Rodrigues; Vollú, Renata Estebanez; de Vasconcelos Goulart, Fátima Regina; Alviano, Daniela Sales; Alviano, Celuta Sales; Seldin, Lucy

    2011-03-01

    Prevention or cure of different illnesses through the use of plant latex is a worldwide known concept. The antifungal activity of Hancornia speciosa latex has been observed against Candida albicans. However, H. speciosa latex is not a sterile plant exudate and secondary metabolites produced by bacteria could be involved in fungal inhibition. In the present study, the bacterial communities of the latex from three H. speciosa trees were characterized using traditional plating and molecular methods. Twelve strains isolated from the latex samples were clustered into four groups by amplified ribosomal DNA restriction analysis (ARDRA). One representative of each group was sequenced and they were identified as belonging to the genera Bacillus, Klebsiella, Enterobacter and Escherichia. None of the 12 isolates showed antifungal activity against C. albicans. A lack of a microbial origin for the antifungal properties of latex was noted. DGGE profiles generated from each of the three latex samples showed unique patterns. Sequencing of the DGGE bands demonstrated the affiliation with the genera Klebsiella, Pantoea, Enterobacter and Burkholderia. In addition, clone libraries were generated and the phylogenetic distribution of the 50 analyzed clones was similar to that obtained using DGGE. The presence of some potential pathogens should be considered before using H. speciosa latex in folk medicine.

  10. Development assessment of natural latex membranes: a new proposal for the treatment of amblyopia

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Jaqueline Alves; Rosa, Suelia Rodrigues Fleury, E-mail: jackalvesribeiro@gmail.com [Laboratorio de Engenharia e Biomaterial (BioEngLab), Faculdade Gama, Universidade de Brasilia (UnB), DF (Brazil); Leite, Cicilia Raquel Maia; Vasconcelos, Claudio Lopes; Soares, Joao Maria [Universidade do Estado do Rio Grande do Norte (UERN), Mossoro, RN (Brazil)

    2017-05-15

    The ophthalmic dysfunction amblyopia, commonly known as lazy eye, is characterized by decreased vision in one eye due to improper development in childhood. The aim of this study was to obtain and characterize natural rubber membranes and to assess their utility as an eye film capable of altering the passage of light. The latex membranes were produced using the Van Gogh method and the deposition technique and were analyzed by physical and chemical methods to determine the properties of latex in natura and of natural rubber membranes. The materials were characterized by X-ray diffractometry, scanning electron microscopy, thermogravimetry, differential scanning calorimetry, analysis of water sorption and light crossing analysis. We report here a new approach to the treatment of patients with amblyopia using latex membranes. (author)

  11. filltex: Automatic queries to ADS and INSPIRE databases to fill LaTex bibliography

    Science.gov (United States)

    Gerosa, Davide; Vallisneri, Michele

    2017-05-01

    filltex is a simple tool to fill LaTex reference lists with records from the ADS and INSPIRE databases. ADS and INSPIRE are the most common databases used among the theoretical physics and astronomy scientific communities, respectively. filltex automatically looks for all citation labels present in a tex document and, by means of web-scraping, downloads all the required citation records from either of the two databases. filltex significantly speeds up the LaTex scientific writing workflow, as all required actions (compile the tex file, fill the bibliography, compile the bibliography, compile the tex file again) are automated in a single command. We also provide an integration of filltex for the macOS LaTex editor TexShop.

  12. 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.

  13. 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.

  14. Effects of latex from "Amapazeiro"Parahancornia amapa (Apocynaceae) on blowfly Chrysomya megacephala (Diptera: Calliphoridae) post-embryonic development.

    Science.gov (United States)

    Mendonça, Paloma M; Lima, Mariana G; Albuquerque, Luis R M; Carvalho, Mario G; Queiroz, Margareth M C

    2011-06-10

    Nowadays, insect control is usually carried out using chemical insecticides, but insect resistance and other negative side effects have prompted the search for alternatives. Biopesticides provide a positive alternative to synthetic pesticides because they have low impact on the environmental, low toxicity to humans and low costs among other advantages. This research was carried out to evaluate the activity of Parahancornia amapa (Huber) Ducke (Apocynaceae) lyophilized latex on the post embryonic development of Chrysomya megacephala (F.) (Diptera: Calliphoridae). Larvae treated with 1.0% latex showed a shorter post embryonic development period (larval, pupal and newly hatched larvae to adult); whereas larvae treated with 3.0% latex provoked a prolongation of these periods. Viability (53%) was also very low at the newly hatched larvae to adult period for larvae treated with 3.0% latex, indicating that latex from P. amapa at high concentrations could change C. megacephala post embryonic development. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. STUDY OF THE PROPERTIES OF THE POLYMER COMPOSITIONS USING THE MODIFIED LATEX COAGULUM

    Directory of Open Access Journals (Sweden)

    A. M. Skachkov

    2014-01-01

    Full Text Available Summary. Properties of the latex coagulum formed during the manufacture of styrene-butadiene latices were investigated. Processing conditions coagulum for further use in the composition of the polymer base composites and rubber compounds were grown. Plasticizers latex coagulum system, improving its handling on the process equipment were developed. In the process of changing the structure of the plasticization of the polymer matrix: solid areas appear in images taken with a scanning probe microscope. Ability to manufacture polymer composites based on treated latex coagulum was shown. When creating the polymeric compositions of styrene-butadiene rubber SCS-30-15 ARKM plasticized coagulum optimum ratio of 70:30 has been selected. Influence the type and dosage of plasticizer viscosity compositions latex coagulum with rubber SKS-30-15 ARKM been established. Application consisting of plasticized polymer base coagulum provides physic-mechanical properties of rubber at the control rules of molded rubber products. It is noted that the best combination of properties of rubber and rubber blends possess samples based polymer compositions coagulum plasticized combination of petroleum oils. It has been established that the use of latex coagulum in the polymer base composition causes sufficiently high values of Mooney viscosity and short curing starts. The influence of active chemical additives (derivatives of saturated fatty acids, 2,2-azo-bis-isobutyronitrile to change the properties of the latex coagulum during machining on a mill was studied. Two ways of handling coagulum in the presence of accelerators mastication was proposed. Found that mixing coagulum accelerators advisable to carry out before the stage of the plasticizing coagulum.

  16. Hierarchically structured self-supported latex films for flexible and semi-transparent electronics

    Energy Technology Data Exchange (ETDEWEB)

    Määttänen, Anni, E-mail: anni.maattanen@abo.fi [Laboratory of Physical Chemistry, Faculty of Science and Engineering, Center for Functional Materials, Åbo Akademi University, Porthaninkatu 3, 20500, Turku (Finland); Ihalainen, Petri, E-mail: petri.ihalainen@abo.fi [Laboratory of Physical Chemistry, Faculty of Science and Engineering, Center for Functional Materials, Åbo Akademi University, Porthaninkatu 3, 20500, Turku (Finland); Törngren, Björn, E-mail: bjorn.torngren@abo.fi [Laboratory of Physical Chemistry, Faculty of Science and Engineering, Center for Functional Materials, Åbo Akademi University, Porthaninkatu 3, 20500, Turku (Finland); Rosqvist, Emil, E-mail: emil.rosqvist@abo.fi [Laboratory of Physical Chemistry, Faculty of Science and Engineering, Center for Functional Materials, Åbo Akademi University, Porthaninkatu 3, 20500, Turku (Finland); Pesonen, Markus, E-mail: markus.pesonen@abo.fi [Physics, Faculty of Science and Engineering, Center for Functional Materials, Åbo Akademi University, Porthaninkatu 3, 20500, Turku (Finland); Peltonen, Jouko, E-mail: jouko.peltonen@abo.fi [Laboratory of Physical Chemistry, Faculty of Science and Engineering, Center for Functional Materials, Åbo Akademi University, Porthaninkatu 3, 20500, Turku (Finland)

    2016-02-28

    Graphical abstract: - Highlights: • Transparent self-supported latex films were fabricated by a peel-off process. • Various template substrates were used for creating e.g. hierarchically structured latex films. • Ultra-thin and semi-transparent conductive gold electrodes were evaporated on the latex films.Electrochemical experiments were carried out to verify the applicability of the electrodes. - Abstract: 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(CH{sub 2}){sub 11}OH (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

  17. The Role of Ammonia in Synthesis of Silver Nanoparticles in Skim Natural Rubber Latex

    OpenAIRE

    Danwanichakul, Panu; Suwatthanarak, Thanawat; Suwanvisith, Chidchanok; Danwanichakul, Duangkamol

    2016-01-01

    Silver nanoparticles (AgNPs) were synthesized in skim natural rubber latex, the by-product from concentrated latex production. The role of ammonia was investigated by varying the concentration to be 0.217, 0.362, 0.377, 0.392, and 0.406 wt%. The emergence of AgNPs was detected by UV-visible spectrophotometer and electrical conductivity meter. Upon increasing ammonia concentration, the ABS peak increased to a maximum and slightly shifted to a higher wavelength and then it decreased afterward a...

  18. 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.

  19. Pilot Scale Production of Irradiated Natural Rubber Latex and its Dipping Products

    OpenAIRE

    M. Utama; Suhartini, M; Herwinarni; (Siswanto), Siswanto; S. Yoharmus; H. Sundaru; H.M. Halik; Prayitno; H.M. Muklis; S. Ruslim

    2005-01-01

    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 co...

  20. 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....

  1. The internal structure of poly(methyl methacrylate) latexes in nonpolar solvents

    DEFF Research Database (Denmark)

    Smith, G.N.; Finlayson, S.D.; Gillespie, D.A.J.

    2016-01-01

    for effective steric stabilizers. However, the PHSA chains do contribute to the intensity of neutron scattering measurements on concentrated dispersions and cannot be ignored. The PMMA cores have a slightly lower density than PMMA homopolymer, which shows that only a small free volume is required to allow small...... molecules to penetrate into the cores. Interestingly, the observations are essentially the same, regardless of the size of the particle; these are general features of these polymer latexes. Despite the latexes being used as a model physical system, the internal chemical structure is complex and must...

  2. Random glycopeptide bead libraries for seromic biomarker discovery

    DEFF Research Database (Denmark)

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

    2010-01-01

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

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

    Science.gov (United States)

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

    2010-01-01

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

  4. Atopic status and latex sensitization in a cohort of 1,628 students of health care faculties.

    Science.gov (United States)

    Wudy, Anna Elena; Negro, Corrado; Adami, Alessandro; Larese Filon, Francesca

    2017-05-01

    Atopic diseases have increased since the second half of the previous century. Atopic workers are at higher risk to be sensitized to latex, and the first years of exposure are supposed to be especially risky. To assess atopic status and rate of latex sensitization in health care students starting their exposure to latex gloves. We analyzed medical surveillance data from 1,628 health care students from 2010 to 2016. Students completed a questionnaire focused on their previous and current latex exposure and personal and family histories of allergic diseases; underwent skin prick testing with common allergens and latex extract (and/or total and latex-specific immunoglobulin E in serum); and underwent a medical examination. Skin prick test results for common inhalant allergens showed that 807 of 1,628 students (49.6%) had atopy. Atopy by skin prick testing was associated with male sex (odds ratio 1.49, 95% confidence interval 1.18-1.86), a personal history of oculorhinitis or asthma (odds ratio 10.22, 95% confidence interval 7.4-14.13), and atopic eczema (odds ratio 1.87, 95% confidence interval 1.05-3.36) at multivariate regression analysis. Eleven students (0.7% of total population) were found to be sensitized to latex and all had atopy. Despite the high prevalence of atopy in health care students of Trieste, the latex sensitization rate is very low and comparable to general population. This is reasonably due to the low exposure to latex gloves at the time of the evaluation and to low latex release from the gloves currently used in our hospital. Copyright © 2017 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-02-22

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

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

    KAUST Repository

    Gooneratne, Chinthaka Pasan

    2011-08-01

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

  7. Selective manipulation of superparamagnetic beads by a magnetic microchip

    KAUST Repository

    Gooneratne, Chinthaka Pasan

    2013-07-01

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

  8. The prevalence of latex sensitisation and allergy and associated risk factors among healthcare workers using hypoallergenic latex gloves at King Edward VIII Hospital, KwaZulu-Natal South Africa: a cross-sectional study

    Science.gov (United States)

    Phaswana, Shumani Makwarela; Naidoo, Saloshni

    2013-01-01

    Objectives The present study describes latex sensitisation and allergy prevalence and associated factors among healthcare workers using hypoallergenic latex gloves at King Edward VIII Hospital in KwaZulu-Natal, South Africa. Design Cross-sectional study. Setting A tertiary hospital in eThekwini municipality, KwaZulu-Natal, South Africa. Participants 600 healthcare workers were randomly selected and 501 (337 exposed and 164 unexposed) participated. Participants who were pregnant, with less than 1 year of work as a healthcare worker and a history of anaphylactic reaction were excluded from the study. Primary and secondary outcome measures Latex sensitisation and latex allergy were the outcome of interest and they were successfully measured. Results The prevalence of latex sensitisation and allergy was observed among exposed workers (7.1% and 5.9%) and unexposed workers (3.1% and 1.8%). Work-related allergy symptoms were significantly higher in exposed workers (40.9%, platex allergy (OR 0.9; 95% CI 0.8 to 0.9). The risk of latex sensitisation (OR 4.2; 95% CI 1.2 to 14.1) and allergy (OR 5.1; 95% CI 1.2 to 21.2) increased with the exclusive use of powder-free latex gloves. A dose–response relationship was observed for powdered latex gloves (OR 1.1; 95% CI 1.0 to 1.2). Atopy (OR 1.5; 95% CI 0.7 to 3.3 and OR 1.4; 95% CI 0.6 to 3.2) and fruit allergy (OR 2.3; 95% CI 0.8 to 6.7 and OR 3.1; 95% CI 1.1 to 9.2) also increased the risk of latex sensitisation and allergy. Conclusions This study adds to previous findings that healthcare workers exposed to hypoallergenic latex gloves are at risk for developing latex sensitisation highlighting its importance as an occupational hazard in healthcare. More research is needed to identify the most cost effective way of implementing a latex-free environment in resource-limited countries, such as South Africa. In addition more cohort analysis is required to better understand the chronicity of illness and disability associated with

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

    Science.gov (United States)

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

    2011-01-01

    Objective The aim of periodontal therapy is the healing of periodontal inflammation; the protection of the attachment and the alveolar bone; and the regeneration of the periodontal structures. In the therapy of periodontitis, supra- and subgingival scaling and root planing plays a main role. The procedure described combines perfect root cleaning without scaling and root planing and minimal invasive periodontal surgery without a scalpel. Material and methods Glass beads of 90 μm were used with the kinetic preparation unit PrepStart® under a pressure of 0.5–5 bar. This technique was practised only under visual control using the OPMI® PRO Magis microscope. Seven examinations were carried out at baseline after 3, 6, 12, 18, 24, and 36 months. Results Time shows a statistically significant influence on all of the considered target variables (P microscope-controlled glass bead blasting results in a perfectly clean root surface using visual control (magnification 20×). Microscope-controlled glass bead blasting is therefore a good alternative to periodontal surgery. PMID:23674909

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

    CERN Document Server

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

    2014-01-01

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

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

    Science.gov (United States)

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

    2013-03-01

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

  12. 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

  13. [The latex agglutination with video digital registration: the enhancement of diagnostic significance of conventional technique].

    Science.gov (United States)

    Starovoĭtova, T A; Steriopolo, N A; Zaĭko, V V; Vengerov, Iu Iu

    2012-02-01

    The rapid semiquantitative latex-tests, because of their analytic characteristics and convenient application, became widespread in the practice of laboratory diagnostics. Though, in spite of high sensitivity and specificity, their diagnostic effectiveness is lower that it could be mainly because of the impossibility to document the results of latex agglutinative re4actions and to manage the objective quality control. The application of systems of video digital registration permits to enhance the clinical significance of these analyses. By means of scanner systems (control and program complex "Expert Lab") the image of analytic objects is received with the results of latex agglutination reaction. The application of program techniques (the programs "Expert Lab - Agglutination" and "Expert Lab - Agglutination - Micros") in data processing permits to get the precise qualitative characteristics of active reactions, to ensure the automatic interpretation of results and gives an opportunity to proceed with the internal laboratory quality control. The saving of analytic object image in computer memory after termination of reaction favors the formation of data base, the implementation of retrospective evaluation of obtained results, additional consultations in dubious cases, including on-line. The application of complex "Expert Lab" permitted to develop the miniaturizes matrix systems permitting to decrease the withdrawal of latex reagents, to increase the productivity of analytical stage of operation preserving all analytical characteristics of method.

  14. MINIMUM NUMBER OF PNEUMOCOCCI REQUIRED FOR CAPSULAR ANTIGEN TO BE DETECTABLE BY LATEX AGGLUTINATION

    NARCIS (Netherlands)

    HOLLOWAY, Y; BOERSMA, WG; KUTTSCHRUTTER, H; SNIJDER, JAM

    Forty-eight strains of Streptococcus pneumoniae were tested in vitro to determine the minimum number required for pneumococcal capsular antigen to be detectable by latex agglutination. It was found that 10(6) to 10(7) microorganisms per ml were needed and that antigen remained detectable even when

  15. Cross-reactivity between Ficus benjamina (weeping fig) and natural rubber latex.

    Science.gov (United States)

    Brehler, R; Abrams, E; Sedlmayr, S

    1998-04-01

    The importance of hypersensitivity to Ficus allergens is reported. Cross-sensitization between fig (Ficus carica), weeping fig (F. benjamina [Fb]), and natural rubber latex (NRL) was confirmed by RAST inhibition. We performed skin prick tests with fresh Fb tree sap and NRL extracts in 346 consecutive patients and in 151 patients with immediate-type hypersensitivity to NRL. Total serum IgE and IgE antibodies to NRL and Ficus spp. were analyzed in sera. By the RAST-inhibition method, we studied cross-reactivity among latex, fig, and weeping fig. Sensitization to Fb was diagnosed in 23 of the 346 consecutive patients, and the simultaneous presence of latex-specific IgE was highly significant. Of 151 NRL-allergic patients, 35 were also sensitized to Fb. Cross-reacting IgE antibodies recognizing latex and Ficus allergens were demonstrated by RAST inhibition. The present study reinforces the importance of Fb as an indoor allergen. Cross-reacting IgE antibodies to NRL and Ficus spp. allergens are frequently found in the sera of atopic patients. Development of commercially available standardized extracts for skin tests is urgently necessary.

  16. Genome sequence of Phytomonas françai a Cassava (Manihot esculenta) latex parasite

    OpenAIRE

    Kelly, S.; Butler, CE; Jaskowska, E

    2017-01-01

    ABSTRACT Here, we report the genome sequence of the cassava (Manihot esculenta) latex parasite Phytomonas fran?ai. P.?fran?ai infection is linked with the yield-loss disease ?chochamento de raizes? (empty roots) in the Unha variety of cassava, a disease characterized by poor root development and chlorosis of the leaves.

  17. Dynamic speciation analysis of atrazine in aqueous latex nanoparticle dispersions using solid phase microextraction (SPME)

    NARCIS (Netherlands)

    Benhabib, K.; Town, R.M.; Leeuwen, van H.P.

    2009-01-01

    Solid phase microextraction (SPME) is applied in the dynamic speciation analysis of the pesticide atrazine in an aqueous medium containing sorbing latex nanoparticles. It is found that the overall rate of extraction of the analyte is faster than in the absence of nanoparticles and governed by the

  18. An electrochemical and optical investigation of polypyrrole/polyethyleneoxide latex particles

    Energy Technology Data Exchange (ETDEWEB)

    Odegard, R.; Skotheim, T.A.; Lee, H.S. (Brookhaven National Lab., Div. of Materials Science, Dept. of Applied Science, Upton, NY (US))

    1991-10-01

    This paper reports that submicronic polypyrrole/polyethylene-oxide (PPy/PEO) latex particles have been produced using PEO as the steric stabilizer and either FeCl{sub 3} or K{sub 2}S{sub 2}O{sub 8} as the oxidizing agent for pyrrole. Scanning electron micrographs show that the two types of PPy/PEO latex particles are of approximately the same size. From electrochemical and optical characterization (UV-vis spectra) of these particles, it was found that these latex particles can be electrochemically oxidized and reduced in an electrolyte of acetonitrile with 0.1M LiCF{sub 3}SO{sub 3}. The electrochemical and optical measurements indicate that the latex particles formed when using K{sub 2}S{sub 2}O{sub 8} as the oxidizing agent are more easily switched than the particles which are the result of applying FeCl{sub 3} as the oxidizing agent.

  19. The case of latex removal for carpet and artificial turf recycling

    NARCIS (Netherlands)

    Bottenberg, E. (Eliza); Bouwhuis, G.H. (Gerrit); Brinks, G.J. (Ger)

    2014-01-01

    For the recycling of carpet and artificial turf the latex backing is often a real stumble block. Many strategies have been developed like freezing the carpet, followed by grinding and subsequent separation of the milled particles. Once it has been separated from its backing materials, PA 6 is

  20. Synthesis, Characterization and Gold Loading of Polystyrene-Poly(pyridyl methacrylate) Core-Shell Latex Systems

    NARCIS (Netherlands)

    Oláh, A.; Hempenius, Mark A.; Vancso, Gyula J.

    2004-01-01

    In this research, novel 3-(2-pyridyl)propyl methacrylate and 3-(3-pyridyloxy)propyl methacrylate monomers were synthesized and emulsion polymerized on colloidal polystyrene seeds, resulting in core–shell latex systems. The cores and the core–shell particles were characterized by static light

  1. 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

  2. Radiation prevulcanized natural rubber latex: Cytotoxicity and safety evaluation on animal

    Science.gov (United States)

    Keong, C. C.; Zin, W. M. Wan; Ibrahim, P.; Ibrahim, S.

    2010-05-01

    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

  3. Antimicrobial activity of a 48-kDa protease (AMP48) from Artocarpus heterophyllus latex.

    Science.gov (United States)

    Siritapetawee, J; Thammasirirak, S; Samosornsuk, W

    2012-01-01

    Artocarpus heterophyllus (jackfruit) is a latex producing plant. Plant latex is produced from secretory cells and contains many intergradients. It also has been used in folk medicine. This study aimed to purify and characterize the biological activities of a protease from jackfruit latex. A protease was isolated and purified from crude latex of a jackfruit tree by acid precipitation and ion exchange chromatography. The proteolytic activities of protein were tested using gelatin- and casein-zymography. The molecular weight and isoelectric point (pl) of protein were analysed by SDS/12.5% PAGE and 2D-PAGE, respectively. Antimicrobial activity of protein was analysed by broth microdilution method. In addition, the antibacterial activity of protein against Pseudomonas aeruginosa ATCC 27853 was observed and measured using atomic force microscopy (AFM) technique. The purified protein contained protease activity by digesting gelatin- and casein-substrates. The protease was designated as antimicrobial protease-48 kDa or AMP48 due to its molecular mass on SDS-PAGE was approximately 48 kDa. The isoelectric point (pl) of AMP48 was approximately 4.2. In addition, AMP48 contained antimicrobial activities by it could inhibit the growths of Pseudomonas aeruginosa ATCC 27853 and clinical isolated Candida albicans at minimum inhibitory concentration (MIC) 2.2 mg/ml and Minimum microbicidal concentration (MMC) 8.8 mg/ml. AFM image also supported the antimicrobial activities of AMP48 by the treated bacterial morphology and size were altered from normal.

  4. Insights on the phytochemical profile (cyclopeptides) and biological activities of Calotropis procera latex organic fractions.

    Science.gov (United States)

    Jucá, Thiago Lustosa; Ramos, Márcio Viana; Moreno, Frederico Bruno Mendes Batista; Viana de Matos, Mayara Patrícia; Marinho-Filho, José Delano Barreto; Moreira, Renato Azevedo; de Oliveira Monteiro-Moreira, Ana Cristina

    2013-01-01

    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  μ g/mL) and lethal to brine shrimp (LD50 10.9 to 65.7  μ g/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.

  5. Shell morphology of core-shell latexes based on conductive polymers

    NARCIS (Netherlands)

    Huijs, F.M; Vercauteren, F.F.; de Ruiter, B.; Kalicharan, D; Hadziioannou, G

    Core-shell latexes with a conductive shell can be used to prepare transparent conducting layers. We have focussed on the relation between the conducting polymer content and the shell morphology and on its influence on conductivity. At low polypyrrole (PPy) concentrations the shell has a smooth

  6. THE PRIMARY STRUCTURE OF HEVAMINE, AN ENZYME WITH LYSOZYME CHITINASE ACTIVITY FROM HEVEA-BRASILIENSIS LATEX

    NARCIS (Netherlands)

    JEKEL, PA; HARTMANN, JBH; BEINTEMA, JJ

    1991-01-01

    The primary structure of hevamine, an enzyme with lysozyme/chitinase activity from Hevea brasiliensis latex, has been determined predominantly with conventional non-automatic methods. The positions of three disulfide bridges have been determined. The sequence has about 60% identity with that of a

  7. 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.

  8. Crystallization of Hevamine, an Enzyme with Lysozyme/Chitinase Activity from Hevea brasiliensis Latex

    NARCIS (Netherlands)

    ROZEBOOM, HJ; BUDIANI, A; BEINTEMA, JJ

    1990-01-01

    Hevamine, an enzyme with both lysozyme and chitinase activity, was isolated and purified from Hevea brasiliensis (rubber tree) latex. The enzyme (molecular weight 29,000) is homologous to certain “pathogenesis-related” proteins from plants, but not to hen egg-white or phage T4 lysozyme. To

  9. Radiation prevulcanized natural rubber latex: Cytotoxicity and safety evaluation on animal

    Energy Technology Data Exchange (ETDEWEB)

    Keong, C C; Zin, W M Wan; Ibrahim, P; Ibrahim, S, E-mail: chai@nuclearmalaysia.gov.my [Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia)

    2010-05-15

    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

  10. 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…

  11. 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.

  12. Fabrication of latex rubber reinforced with micellar nanoparticle as an interface modifier

    Science.gov (United States)

    Reinforced latex rubbers were fabricated by incorporating small amount of nanoparticles as interface modifier. The rubbers were fabricated in a compression mold at 130°C. The incorporated nanoparticles were prepared from wheat protein (gliadin) and ethyl cyanoacrylate (ECA). These nanoparticles were...

  13. Harvest height and frequency effects on guayule latex, rubbers, and resin yields

    Science.gov (United States)

    Guayule (Parthenium argentatum Gray) is a perennial shrub native to the Chihuahuan Desert. The commercialization of guayule for hypoallergenic latex and other products such as resin for termite resistant wood products and as an energy source have renewed interest in production practices such as harv...

  14. Insights on the Phytochemical Profile (Cyclopeptides) and Biological Activities of Calotropis procera Latex Organic Fractions

    Science.gov (United States)

    Jucá, Thiago Lustosa; Ramos, Márcio Viana; Moreno, Frederico Bruno Mendes Batista; Viana de Matos, Mayara Patrícia; Marinho-Filho, José Delano Barreto; Moreira, Renato Azevedo; Monteiro-Moreira, Ana Cristina de Oliveira

    2013-01-01

    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. PMID:24348174

  15. 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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. The effects of temperature and pH bacterial degradation of latex ...

    African Journals Online (AJOL)

    The goal of this study was to integrate the activities of paint deterioration of microbial communities (microcosms) on the basis of environmental factors. The effect of temperature and pH on bacterial degradation of latex paint under humid condition by bacterial isolates was studied. Results obtained revealed that paint ...

  17. Wound-healing and potential anti-keloidal properties of the latex of ...

    African Journals Online (AJOL)

    Calotropis Procera (CP) has been used in the management of toothache, fresh skin burns, gum bleeding as well as others to make it qualify as a medicinal plant. This study was designed to assess its wound-healing property in rabbits and its potentials for anti keloidal activity.Fresh latex of Calotropis were obtained and ...

  18. Costs and return analysis in rubber latex production in Edo State ...

    African Journals Online (AJOL)

    The study examined the costs and return analysis in rubber latex production in Edo Sate, Nigeria. Multi-stage sampling method was adopted to select 96 smallholder rubber framers for the study. The first stage was a purposive sampling of two LGAs and then simple random sampling of 6 villages each from the two LGA.

  19. MEASUREMENTS OF VOLATILE ORGANIC COMPOUNDS AND PARTICLES DURING APPLICATION OF LATEX PAINT WITH AN AIRLESS SPRAYER

    Science.gov (United States)

    The paper discusses experiments, conducted at EPA's Indoor Air Quality Research House, to measure airborne concentrations of volatile organic compounds (VOCs) and particles during and following the spray-application of latex wall paint. (NOTE: Paint may be applied indoors by a v...

  20. CHARACTERIZATION AND REDUCTION OF FORMALDEHYDE EMISSIONS FROM A LOW-VOC LATEX PAINT

    Science.gov (United States)

    The paper discusses the measurment and analysis of the patterns of formaldehyde emission from a low volatile organic compound (VOC) latex paint applied to gypsum board, using small environmental chamber tests. The formaldehyde emissions resulted in sharp increase of chamber air...

  1. Concentration of field and skim latex by microfiltration - membrane fouling and biochemical methane potential of serum.

    Science.gov (United States)

    Thongmak, Narumol; Sridang, Porntip; Puetpaiboon, Udomphon; Grasmick, Alain

    2015-01-01

    Cross-flow microfiltration was used to concentrate field and skim latex suspensions and recover the smallest compounds (proteins, sugars, etc.) in permeate (serum solutions). The experiments were performed in a lab-scale microfiltration unit equipped with ceramic membranes. In continuous mode, the operations were performed at constant trans-membrane pressure (0.5 bars), constant cross-flow velocity (3 m/s) and constant temperature (28 ± 2°C). In retentate, the volumetric concentration factor was only close to 2 (about 54% of total solid content, TSC) when concentrating the field latex suspensions, and it reached 10 (close to 40% TSC) when concentrating skim latex suspensions. The quality of retentate suspensions let envisage a significant potential of industrial valorization. The membrane fouling rates appeared as an increasing function of dry rubber content suspension, and the main fouling origin (94%) was linked to a reversible accumulation of suspended compounds on the membrane surface. Permeate appeared as a clear yellow solution containing the smallest soluble organic fractions that show a high degree of biodegradability when using biochemical methane potential tests. The chemical oxygen demand (COD) removal was then higher than 92% and the methane production yield was close to 0.29 NLCH4/gCODremoved. The association of a membrane separation step and anaerobic digestion appeared, then, as a relevant solution to recover rubber content from skim latex suspensions and energy from the anaerobic digestion of serum.

  2. Lobelia siphilitica Plants That Escape Herbivory in Time Also Have Reduced Latex Production

    Science.gov (United States)

    Parachnowitsch, Amy L.; Caruso, Christina M.; Campbell, Stuart A.; Kessler, André

    2012-01-01

    Flowering phenology is an important determinant of a plant’s reproductive success. Both assortative mating and niche construction can result in the evolution of correlations between phenology and other reproductive, functional, and life history traits. Correlations between phenology and herbivore defence traits are particularly likely because the timing of flowering can allow a plant to escape herbivory. To test whether herbivore escape and defence are correlated, we estimated phenotypic and genetic correlations between flowering phenology and latex production in greenhouse-grown Lobelia siphilitica L. (Lobeliaceae). Lobelia siphilitica plants that flower later escape herbivory by a specialist pre-dispersal seed predator, and thus should invest fewer resources in defence. Consistent with this prediction, we found that later flowering was phenotypically and genetically correlated with reduced latex production. To test whether herbivore escape and latex production were costly, we also measured four fitness correlates. Flowering phenology was negatively genetically correlated with three out of four fitness estimates, suggesting that herbivore escape can be costly. In contrast, we did not find evidence for costs of latex production. Generally, our results suggest that herbivore escape and defence traits will not evolve independently in L. siphilitica. PMID:22662205

  3. Stokes and anti-stokes stimulated Mie scattering on nanoparticle suspensions of latex

    Science.gov (United States)

    Burkhanov, I. S.; Krivokhizha, S. V.; Chaikov, L. L.

    2016-12-01

    Stokes and anti-Stokes shifts of stimulated concentration light scattering (SCLS, stimulated Mie scattering) in suspensions of various-sized latex nanoparticles in water were measured by the light guide scheme, under conditions of backscattering in the presence of convection.

  4. 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...

  5. Factors affecting the anthelmintic efficacy of papaya latex in vivo: host sex and intensity of infection.

    Science.gov (United States)

    Luoga, Wenceslaus; Mansur, Fadlul; Lowe, Ann; Duce, Ian R; Buttle, David J; Behnke, Jerzy M

    2015-07-01

    The development of plant-derived cysteine proteinases, such as those in papaya latex, as novel anthelmintics requires that the variables affecting efficacy be fully evaluated. Here, we conducted two experiments, the first to test for any effect of host sex and the second to determine whether the intensity of the worm burden carried by mice would influence efficacy. In both experiments, we used the standard C3H mouse reference strain in which papaya latex supernatant (PLS) consistently shows >80 % reduction in Heligmosomoides bakeri worm burdens, but to broaden the perspective, we also included for comparison mice of other strains that are known to respond more poorly to treatment with papaya latex. Our results confirmed that there is a strong genetic influence affecting efficacy of PLS in removing adult worm burdens. However, there was no effect of host sex on efficacy (C3H and NIH) and no effect of infection intensity (C3H and BALB/c). These results offer optimism that plant-derived cysteine proteinases (CPs), such as these from papaya latex, can function as effective anthelmintics, with neither host sex nor infection intensity presenting further hurdles to impede their development for future medicinal and veterinary usage.

  6. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-03-12

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

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

    Science.gov (United States)

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

    2003-04-01

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

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

    Directory of Open Access Journals (Sweden)

    Anikeeva Olga Viktorovna

    2015-06-01

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

  10. 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. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. Glycosidic activities of Candida albicans after action of vegetable latex saps (natural antifungals) and isoconazole (synthetic antifungal).

    Science.gov (United States)

    Giordani, R; Moulin-Traffort, J; Régli, P

    1991-01-01

    Glycosidic activities have been examined in Candida albicans grown on medium culture containing latex sap (natural antifungal) or isoconazole (synthetic antifungal). The different types of utilized latex sap were those of Lactuca sativa (latex exuded from articulated laticifers) and Asclepias curassavica (latex flowing from non-articulated laticifers). The same enzyme assays were performed on C. albicans grown without antifungal compounds. Except for alpha-arabinosidase, all glycosidase activities were increased when C. albicans was grown in medium supplemented with L. sativa latex sap. The most stimulated activities were those of beta-fucosidase, alpha-galactosidase, alpha- and beta-glucosidase, alpha- and beta-mannosidase, acetyl-beta-glucosaminidase. The presence of A. curassavica latex sap in culture medium produced similar results: the most stimulated activities were those of alpha-mannosidase, alpha-galactosidase, acetyl-beta-glucosaminidase and beta-fucosidase. Electron microscope observations suggested a correlation between this stimulation of glycosidic activities and the fungal cell wall breakdown. For comparison the presence of isoconazole in culture medium yields no increase in glycosidic activities and no ultrastructural modification of fungal cell wall. The mode of action of latex saps in cell wall breakdown is discussed.

  12. Effectiveness and feasibility of methanol extracted latex of Calotropis procera as larvicide against dengue vectors of western Rajasthan, India.

    Science.gov (United States)

    Singhi, Manju; Purohit, Anil; Chattopadhyay, Sushmita

    2015-06-01

    Identification of novel effective larvicide from natural resources is essential to combat developing resistances, environmental concerns, residue problems and high cost of synthetic insecticides. Results of earlier laboratory findings have shown that Calotropis procera extracts showed larvicidal, ovicidal and refractory properties towards ovipositioning of dengue vectors; further, latex extracted with methanol was found to be more effective compared to crude latex. For testing efficacy and feasibility of extracted latex in field, the present study was undertaken in different settings of Jodhpur City, India against dengue vectors. Study areas were selected based on surveillance design for the control of dengue vectors. During the study period domestic and peri-domestic breeding containers were treated with methanol extracted latex and mortality was observed after 24 h as per WHO guidelines. Latex was manually collected from internodes of Calotropis procera and extracted using methanol (AR) grade. Methanol extracted latex of C. procera was found effective and feasible larvicide against dengue vectors in the field conditions. Cement tanks, clay pots and coolers (breeding sites) were observed as key containers for the control of dengue transmission. Today environmental safety is considered to be very important. Herbal composition prepared by the extraction of latex of C. procera can be used as an alternative approach for the control of dengue vectors. This will reduce the dependence on expensive products and stimulate local efforts to enhance the public involvement.

  13. Field Evaluation of Culture plus Latex Sweep Serotyping for Detection of Multiple Pneumococcal Serotype Colonisation in Infants and Young Children

    Science.gov (United States)

    Turner, Paul; Turner, Claudia; Jankhot, Auscharee; Phakaudom, Kawalee; Nosten, Francois; Goldblatt, David

    2013-01-01

    Background Nasopharyngeal swab (NPS) culture by World Health Organisation (WHO) methodology underestimates multiple pneumococcal serotype colonisation compared to a simple culture and latex sweep method. The impacts of this on descriptions of pneumococcal serotype distributions and colonisation dynamics in infancy are not clear. Methods 8,736 NPS collected from infants enrolled into a longitudinal study were processed to evaluate the field utility of the latex sweep method. 1,107 had previously been cultured by WHO methodology. Additionally, colonisation results were compared in 100 matched pairs of infants, where swabs from an individual were cultured either by WHO or latex sweep method. Results In 1,107 swabs cultured by both methods, the latex sweep method was three times more likely to detect colonisation with multiple pneumococcal serotypes than the WHO method (platex sweep (p = 0.03). The overall rate of non-vaccine type pneumococcal acquisition was also greater in infants cultured by latex sweep (p = 0.04). Conclusions Latex sweep serotyping was feasible to perform on a large specimen collection. Multiple serotype colonisation detection was significantly improved compared with WHO methodology. However, use of the latex sweep method is unlikely to significantly alter colonisation study serotype distribution or colonisation dynamics results. PMID:23844133

  14. In vitro efficacy of latex and purified papain from Carica papaya against Strongyloides venezuelensis eggs and larvae.

    Science.gov (United States)

    Moraes, Dayane; Levenhagen, Marcelo Arantes; Costa-Cruz, Julia Maria; Costa, Antônio Paulino da; Rodrigues, Rosângela Maria

    2017-04-03

    Latex from Carica papaya is rich in bioactive compounds, especially papain, which may help to control parasitic diseases. This study evaluated the efficacy of latex from C. papaya and purified papain against Strongyloides venezuelensis. The Egg Hatching Test (EHT) and the Larval Motility Test (LMT) using fresh and frozen latex (250mg/mL), lyophilized latex (34mg/mL), and purified papain (2.8 mg/mL) were performed. Albendazole (0.025 mg/mL) and ivermectin (316 ppm) were used as positive controls. EHT and LMT were carried out through the incubation of each solution with S. venezuelensis eggs or larvae (± 100 specimens), and results were analyzed after 48h (EHT) or 24, 48, and 72h (LMT). EHT showed that latex preparations at higher concentrations (1:10 to 1:100) resulted in partial or complete destruction of eggs and larvae inside the eggs. The result from the 1:1,000 dilution was similar to the positive control. LMT showed effectiveness in all the tested dilutions compared to negative controls. Purified papain showed a dose-dependent response in the EHT. Purified papain (2.8 mg/ mL) showed similar results to lyophilized latex at 1:1,000 in the EHT. Latex and purified papain from C. papaya were effective against S. venezuelensis eggs and larvae in vitro, suggesting their potential use as an alternative treatment for strongyloidiasis.

  15. 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.

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

    Science.gov (United States)

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

    2007-03-01

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

  17. 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.

  18. Rapid detection of human and canine visceral leishmaniasis: assessment of a latex agglutination test based on the A2 antigen from amastigote forms of Leishmania infantum.

    Science.gov (United States)

    Akhoundi, Behnaz; Mohebali, Mehdi; Shojaee, Saeedeh; Jalali, Mahmoud; Kazemi, Bahram; Bandehpour, Mojgan; Keshavarz, Hossein; Edrissian, Gholam Hossein; Eslami, Mohammad Bagher; Malekafzali, Hossein; Kouchaki, Ameneh

    2013-03-01

    The diagnosis of visceral leishmaniasis (VL) in humans and animal reservoir hosts is difficult, particularly in rural areas where the disease is endemic and laboratory facilities are limited. This study aimed to develop a latex agglutination test (LAT) for the rapid detection of anti-Leishmania antibodies against the A2 antigen derived from the amastigote form as well as those against crude antigens derived from the promastigote form of an Iranian strain of Leishmania (Leishmania) infantum. The A2 antigen (42-100 kDa) was prepared from the amastigote form of L. infantum, purified with electroelution and compared with the crude antigen from the promastigote form of L. infantum. Both antigens showed appropriate intensity reactions, were selected using dot blotting of positive and negative pooled sera and used to sensitize 0.9-μm latex beads. The tests were carried out on sera from 43 symptomatic, human patients with VL confirmed by parasitological examination and direct agglutination test (DAT), 30 healthy controls and 32 patients with other infections but without VL. Canine sera were collected from 63 domestic dogs with VL confirmed using parasitological examinations and DAT and 31 healthy dogs from areas non-endemic for VL. Compared with the controls, human sera from DAT-confirmed patients yielded a sensitivity of 88.4% (95% CI, 82.1-94.5%) and specificity of 93.5% (95% CI, 87.0-99.7%) on A2-LAT (amastigote) when 1:3200 was used as the cut-off titre. A good degree of agreement was found between A2-LAT and DAT (0.914). LAT required 3-5 min to complete, versus the 12-18 h needed for DAT. Compared with the controls, A2-LAT of canine sera from DAT-confirmed cases yielded a sensitivity of 95.2% (95% CI, 95.0-95.4%) and specificity of 100% (95% CI 100%) when 1:320 was used as the cut-off titre. A good degree of agreement was found between A2-LAT and DAT (0.968). Similarly, the sensitivity and specificity of Pro.-LAT (promastigote) was calculated to be 88.4% and 91

  19. Involvement of prostaglandins in inflammation induced by latex of Calotropis procera.

    Science.gov (United States)

    Kumar, Vijay L; Shivkar, Yatin M

    2004-01-01

    INTRODUCTION:The aerial parts of the plant Calotropis procera produce milky white latex that causes inflammation of the skin and mucous membranes. Prostaglandins are one of the mediators released in an inflammatory response following induction of cyclooxygenase (COX). In the present study, we have evaluated the role of prostaglandins in inflammatory response elicited by the latex of C. procera. METHODS: Aqueous extract of dried latex of C. procera was injected into the 6-day air-pouch in the rat. The inflammatory response was evaluated by studying the air-pouch fluid for its volume, protein and prostaglandin (PG) E2 concentrations, and leucocyte counts. The granulation tissue from the pouch was quantified and studied for COX-2 expression by reverse transcriptase-polymerase chain reaction. The inhibitory effect of celecoxib and dexamethasone was evaluated on the aforementioned parameters. RESULTS: Dried latex produced an inflammatory response that was maximum at 6 h. It was associated with the accumulation of protein-rich fluid, leucocytes and PGE2 production. It also resulted in granulation of the pouch cavity that was a maximum on day 3. COX-2 expression could be detected in the granulation tissue on day 1 and it increased progressively up to day 5. The anti-inflammatory drugs celecoxib and dexamethasone significantly attenuated the inflammatory response and inhibited COX-2 expression in granulation tissue. CONCLUSIONS: Latex of C. procera induces an inflammatory response characterized by an early exudative phase accompanied by PGE2 production and a late proliferative phase associated with COX-2 induction. Both the phases were effectively inhibited by COX-2 inhibitors. PMID:15223605

  20. 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%.

  1. Mercury sensing and toxicity studies of novel latex fabricated silver nanoparticles.

    Science.gov (United States)

    Borase, Hemant P; Patil, Chandrashekhar D; Salunkhe, Rahul B; Suryawanshi, Rahul K; Salunke, Bipinchandra K; Patil, Satish V

    2014-11-01

    Safe and eco-friendly alternatives to currently used hazardous chemico-physical methods of silver nanoparticles (AgNPs) synthesis are need of time. Rapid, low cost, selective detection of toxic metals in environmental sample is important to take safety action. Toxicity assessment of engineered AgNPs is essential to avoid its side effects on human and non-target organisms. In the present study, biologically active latex from Euphorbia heterophylla (Poinsettia) was utilized for synthesis of AgNPs. AgNPs was of spherical shape and narrow size range (20-50 nm). Occurrence of elemental silver and crystalline nature of AgNPs was analyzed. Role of latex metabolites in reduction and stabilization of AgNPs was analyzed by FT-IR, protein coagulation test and phytochemical analysis. Latex-synthesized AgNPs showed potential in selective and sensitive detection of toxic mercury ions (Hg(2+)) with limit of detection around 100 ppb. Addition of Hg(2+) showed marked deviation in color and surface plasmon resonance spectra of AgNPs. Toxicity studies on aquatic non-target species Daphnia magna showed that latex-synthesized AgNPs (20.66 ± 1.52% immobilization) were comparatively very less toxic than chemically synthesized AgNPs (51.66 ± 1.52% immobilization). Similarly, comparative toxicity study on human red blood cells showed lower hemolysis (4.46 ± 0.01%) by latex-synthesized AgNPs as compared to chemically synthesized AgNPs causing 6.14 ± 0.01% hemolysis.

  2. Development of fingermarks on Latex gloves: The solution to a challenging surface.

    Science.gov (United States)

    Arbeli, Tomer; Liptz, Yakir; Bengiat, Ravell; Levin-Elad, Michal

    2017-11-01

    Used Latex gloves found at crime scenes can provide strong evidence against a suspect as they almost certainly contain both the fingermarks and DNA of the perpetrator who had worn them. However, over the years, Latex gloves have proved to be a rather difficult substrate for fingermarks development, with most of the standard techniques producing poor results. In this study, the two main protocols for development on either porous or non-porous surfaces: Ninhydrin-HFE and superglue fuming followed by crystal violet (CV) dyeing, respectively, had been examined on 100 disposable Latex gloves from twenty five donors. The results distinctly showed a high superiority of Ninhydrin-HFE over the superglue fuming indicating the porous rather than the non-porous properties of the interior of the gloves. Yet, not all the usual ninhydrin development formulations yielded the desirable results, leading to the conclusion that the success of development rests on the solvent-sensitive structure of the gloves. As natural latex contains contaminant proteins, that were found to cause allergic reactions in different people, the manufacturing of disposable gloves had been altered over the years to prevent contact with these proteins by adding an intrinsic polymer-coating. Thus, it was essential to use an inert solvent system that should keep the interior polymer-coating intact, allowing a reaction only with the amino acids on the surface rather than the latex proteins in the glove. The SEM analyses showed that HFE-7100 as opposed to petroleum ether, does not harm the inner coating, hence, providing the ideal solution to this challenging surface. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. SparseBeads data: benchmarking sparsity-regularized computed tomography

    Science.gov (United States)

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

    2017-12-01

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

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

    Directory of Open Access Journals (Sweden)

    Peter Kotschy

    2011-01-01

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

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

    Science.gov (United States)

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

    2012-01-01

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

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

    Science.gov (United States)

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

    2014-07-01

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

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

    Science.gov (United States)

    Woodward, J.

    1998-12-08

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

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

    Science.gov (United States)

    Nasarabadi, Shanavaz [Livermore, CA

    2011-01-11

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

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

    Science.gov (United States)

    Gmachowski, L

    2001-10-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-12-01

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

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

    Science.gov (United States)

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

    2016-11-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-03-15

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

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

    OpenAIRE

    Gibson, Robert O; Koerper, Henry C.

    2000-01-01

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

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

    Science.gov (United States)

    Bayramoglu, Gulay; Yakup Arica, M

    2014-02-01

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

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

    Science.gov (United States)

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

    2016-10-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-05-19

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

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

    Science.gov (United States)

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

    2007-06-15

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

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2007-03-01

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

  20. Anticancer and cytotoxic properties of the latex of Calotropis procera in a transgenic mouse model of hepatocellular carcinoma

    OpenAIRE

    Choedon, Tenzin; Mathan, Ganeshan; Arya, Soneera; Kumar, Vijay L.; Kumar, Vijay

    2006-01-01

    AIM: To evaluate the anticancer property of the dried latex (DL) of Calotropis procera, a tropical medicinal plant, in the X15-myc transgenic mouse model of hepatocellular carcinoma and to elucidate its mechanism of action in cell culture.

  1. First record of the behavior of latex drainage by Trigona spinipes (Fabricius (Hymenoptera, Apidae in laticiferous flowers

    Directory of Open Access Journals (Sweden)

    Cristiana Koschnitzke

    2011-09-01

    Full Text Available This paper describes the behavior of the bee Trigona spinipes, to avoid the latex, when piercing the base of the tubular corolla of the flowers of Mandevilla guanabarica in order to steal the nectar.

  2. Robust Optimization of Alginate-Carbopol 940 Bead Formulations

    Science.gov (United States)

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

    2012-01-01

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

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

    Science.gov (United States)

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

    2017-01-01

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

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

    Science.gov (United States)

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

    2018-01-24

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

  5. Simulation of Enzyme Catalysis in Calcium Alginate Beads

    Directory of Open Access Journals (Sweden)

    Ameel M. R. Al-Mayah

    2012-01-01

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

  6. Robust Optimization of Alginate-Carbopol 940 Bead Formulations

    Directory of Open Access Journals (Sweden)

    J. M. López-Cacho

    2012-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Mikoláš Kesely

    2016-04-01

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

  8. Triboelectric generator based on a moving charged bead

    Science.gov (United States)

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

    2016-11-01

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

  9. Magnetic bead based assays for complement component C5.

    Science.gov (United States)

    DiScipio, Richard G; Schraufstatter, Ingrid U

    2017-11-01

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

  10. Biodegradability and aging study of rubber films obtained by gamma radiation vulcanization processes of latex; Estudo da biodegradabilidade e envelhecimento de filmes de borracha obtidos por processos de vulcanizacao do latex por radiacao induzida de fonte gama

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Carlos Felipe Pinto

    2005-07-01

    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 {sup 60}C 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)

  11. Hipersensibilidad al latex en el peri-operatório: una revisión integradora de la literatura

    OpenAIRE

    Aline Nair Biaggio Mota; Ruth Natalia Teresa Turrini

    2012-01-01

    This article characterizes hypersensitivity reactions during anesthetic-surgical procedures. This integrative literature review was conducted in the LILACS, CINAHL, COCHRANE and MEDLINE databases including papers published from 1966 to September 2011. A total of 17 case reports, two prevalence studies and one cohort study were identified. Latex reactions were mainly type III and the primary source of intraoperative reaction was latex gloves. The average time for clinical manifestation was 59....

  12. Surgical gloves fabrication using natural rubber latex vulcanized with gamma radiation; Fabricacao de luvas cirurgicas com latex de borracha natural vulcanizado com raios gama

    Energy Technology Data Exchange (ETDEWEB)

    Collantes, Hugo David Chirinos

    1995-12-31

    Surgical gloves were manufactured by immersion coagulant method from vulcanized natural rubber latex by gamma rays at dose of 10 kGy in the air, at room temperature, using the following sensitizer vulcanization An-B 3 phr/KOH 0.2 phr. The influence of the parameter in the thickness of the surgical gloves manufacture, studied through fractional factorial designs technic, can be resumed by empirical linear correlation: y = 0.213 + 0.025 [Ca Cl{sub 2}] + 0.019 t. (author). 49 refs., 13 figs., 31 tabs.

  13. Personal exposure to inhalable dust and the specific latex aero-allergen, Hev b6.02, in latex glove manufacturing in Thailand.

    Science.gov (United States)

    Sanguanchaiyakrit, Nuthchyawach; Povey, Andrew C; de Vocht, Frank

    2014-06-01

    Latex product manufacturing is an important industry in south-east Asia but has the potential for considerable occupational exposure of workers to latex allergens. Although exposure to latex allergens can result in adverse health reactions, few studies to characterize this exposure have been conducted to date. This study therefore aimed to characterize current airborne inhalable dust and the specific allergen, Hev b 6.02, exposures in this industry in Thailand. Workers were recruited from three factories in the southern part of Thailand. Full-shift inhalable dust personal air sampling was conducted using IOM sampling heads equipped with polytetrafluoroethylene filters at a 2.0 l min(-1) flowrate. After weighing to determine inhalable dust levels, filters were extracted and analysed for Hev b 6.02 using an enzyme immunometric assay. Two hundred and seventy-five workers agreed to participate, resulting in a total of 292 measurements. Geometric mean (GM) personal exposure to inhalable dust was 0.88 mg m(-3), but individual exposures up to 12.34 mg m(-3) were measured. The pattern of exposure was similar across factories, with highest exposures in the stripping (GM 2.08-4.05 mg m(-3) for the 3 factories) and tumbling departments (1.11-2.17 mg m(-3)). Within-worker (day-to-day) variability contributed 92% to total variability. The Hev b 6.02 exposure pattern was similar with time-weighted average GM exposure levels in the oldest factory ranging from 8.7 mg m(-3) in the laboratory to 30.2mg m(-3) in the stripping department. In contrast to inhalable dust exposure, total exposure variability was primary driven by variability between workers (67%). Workers in these latex product factories get routinely exposed to measurable Hev b 6.02 levels, which may give rise to increased incidence of allergic symptoms and occupational asthma. Also, in this measurement campaign a 10mg m(-3), but not 15 mg m(-3), occupational exposure limit for inhalable dust was occasionally exceeded

  14. Performance Improvement of Latex-Based PSAs using Polymer Microstructure Control

    Science.gov (United States)

    Qie, Lili

    This thesis aims to improve the performance of latex-based pressure-sensitive adhesives (PSAs). PSA performance is usually evaluated by tack, peel strength and shear strength. Tack and peel strength characterize a PSA's bonding strength to a substrate while shear strength reflects a PSA's capability to resist shear deformation. In general, increasing shear strength leads to a decrease in tack and peel strength. While there are several commercial PSA synthesis methods, the two most important methods consist of either solvent-based or latex-based techniques. While latex-based PSAs are more environmentally compliant than solvent-based PSAs, they tend to have much lower shear strength, at similar tack and peel strength levels. Therefore, the goal in this thesis was to greatly improve the shear strength of latex-based PSAs at little to no sacrifice to tack and peel strength. In this study, controlling the polymer microstructure of latexes or their corresponding PSA films was used as the main method for improving the PSA performance. The research was sub-divided into four parts. First, the influence of chain transfer agent (CTA) and cross-linker on latex polymer microstructure was studied via seeded semi-batch emulsion polymerization of butyl acrylate (BA) and methyl methacrylate (MMA). Three techniques were used to produce the latexes: (1) adding CTA only, (2) adding cross-linker only, and (3) adding both CTA and cross-linker. It was found that using CTA and cross-linker simultaneously allows one to expand the range of latex microstructural possibilities. For example, latexes with similar gel contents but different Mc (molecular weight between cross-links) and Mw (molecular weight of sol polymers) could be produced if CTA and cross-linker concentration are both increased. However, for the corresponding PSAs with similar gel contents, the relationship between their polymer microstructure and performance was difficult to establish as almost all of the medium and high gel

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

    Directory of Open Access Journals (Sweden)

    Harikrishnan Jayamohan

    2015-05-01

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

  16. Latex-protein complexes from an acute phase recombinant antigen of Toxoplasma gondii for the diagnosis of recently acquired toxoplasmosis.

    Science.gov (United States)

    Peretti, Leandro E; Gonzalez, Verónica D G; Marcipar, Iván S; Gugliotta, Luis M

    2014-08-01

    The synthesis and characterization of latex-protein complexes (LPC), from the acute phase recombinant antigen P35 (P35Ag) of Toxoplasma gondii and "core-shell" carboxylated or polystyrene (PS) latexes (of different sizes and charge densities) are considered, with the aim of producing immunoagglutination reagents able to detect recently acquired toxoplasmosis. Physical adsorption (PA) and chemical coupling (CC) of P35Ag onto latex particles at different pH were investigated. Greater amounts of adsorbed protein were obtained on PS latexes than on carboxylated latexes, indicating that hydrophobic forces govern the interactions between the protein and the particle surface. In the CC experiments, the highest amount of bound protein was obtained at pH 6, near the isoelectric point of the protein (IP=6.27). At this pH, it decreased both the repulsion between particle surface and protein, and the repulsion between neighboring molecules. The LPC were characterized and the antigenicity of the P35Ag protein coupled on the particles surface was evaluated by Enzyme-Linked ImmunoSorbent Assay (ELISA). Results from ELISA showed that the P35Ag coupled to the latex particles surface was not affected during the particles sensitization by PA and CC and the produced LPC were able to recognize specific anti-P35Ag antibodies present in the acute phase of the disease. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Prevalence of manufacturing defects in latex examination gloves used in selected dental practices in central Saudi Arabia.

    Science.gov (United States)

    Al-Swuailem, Abdullah S

    2014-07-01

    To assess the defect rates in latex examination gloves used in selected dental practices in Riyadh, Saudi Arabia. In this cross-sectional study, a total of 796 latex examination gloves were collected from 5 governmental hospitals and 5 private dental practices between April 2012 and May 2012. The gloves were assessed for presence of defects visually (VT) and using water inflation test (WIT). One and 2 sample t-tests were used to assess significant differences in defect rates among each latex brand, and between governmental hospitals and private dental practices. Defects in latex gloves were more likely to be identified using WIT compared with VT (20.2% versus 4.3%, p=0.000). Using WIT, examined latex gloves had a defect rate approximately 8 times the acceptable quality level of 2.5% (20.2%, p=0.000). Using WIT, gloves used in private dental practices had significantly higher defect rates compared with governmental dental clinics (25.6% versus 14.6%, p=0.006). Most latex examination gloves used in the sampled governmental dental clinics and private dental practices in Riyadh had significantly higher preexisting defect rates than acceptable standard levels.

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

    Peng, Jing; Wang, Maolin; Qiao, Jinliang; Wei, Genshuan

    2005-04-01

    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.

  20. Organic/Inorganic Composite Latexes: The Marriage of Emulsion Polymerization and Inorganic Chemistry

    Science.gov (United States)

    Bourgeat-Lami, Elodie; Lansalot, Muriel

    This review article describes recent advances in the synthesis and properties of waterborne organic/inorganic colloids elaborated through conventional emulsion polymerization, a well-established technology. These materials can be defined as aqueous suspensions of composite latex particles made up of organic and inorganic domains organized into well-defined core-shell, multinuclear, raspberry-like, multipod-like, or armored morphologies. Particular emphasis is placed on the synthetic strategies for fabrication of these colloidal materials. Two main approaches are described: the polymerization of organic monomers in the presence of preformed inorganic particles, and the reverse approach by which inorganic materials are synthesized in the presence of preformed polymer latexes. The list of examples provided in this review is by no means exhaustive but rather intends to give an overview of synthetic methods for selected inorganic compounds (e.g., silica, iron oxide, pigments, clays, quantum dots, and metals), and briefly reports on potential applications of the resulting materials.