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Sample records for natural latex graft

  1. Radiation graft copolymerization of n-butyl acrylate on natural rubber latex

    International Nuclear Information System (INIS)

    Sundardi, F.; Kadariah, S.

    1986-01-01

    A method of radiation graft copolymerization of n-butyl acrylate (NBA) on natural rubber (NR) latex has been studied. The rate of conversion increases with the increase of NBA in latex. An irradiation dose of about 12 kGy is needed to obtain 90% conversion with 40 phr of NBA in latex. Tensile strength, tear strength, and elongation at break of grafted NR are found to decrease with increasing degree of grafting. The physical strength of a vulcanizate prepared from a mixture of NR and ply-NBA was found to be better than that of NBA-NR graft copolymer vulcanizate. The graft copolymerization reaction takes place in the outer layer of NR particles, and because the secondary bonds between poly-NBA molecules may be weaker than those between NR molecules, the existence of a poly-NBA layer in NR particles will decrease its physical strength

  2. Study on grafting of monomer onto natural rubber latex by radiation technique

    International Nuclear Information System (INIS)

    Nguyen Tan Man; Le Hai; Tran Thi Tam; Le Huu Tu, Pham Thi Sam; Dao Minh Phuong; Ha Thuc Huy

    2004-01-01

    Radiation vulcanization of natural rubber latex has been extensively developed through programmers assisted by the IAEA and UNDP under RCA in Asia and Pacific Region. R-D has been done in most of the Member States with technical assistance from Japan's Takasaki Radiation Chemistry Establishment. Radiation vulcanized natural rubber latex (RVNRL) has many advantages over the conventional sulfur vulcanized latex, such as absence of nitrosamine and low cytotoxicity. Radiation crosslinking is a room temperature process, itself an important cost advantage, it is easily controlled and desired extend of crosslinking is easily achieved by controlling the dose (irradiation time). Disadvantages of RVNRL to be improved are poor physical properties of film such as low tensile strength and tear strength. The research groups of Japan, Thailand and Indonesia concentrated on the improvement of physical properties of RVNRL using radiation grafted PMMA as additive [2]. F. Sundardi and W. Sofiarti have reported that tensile strength and hardness increased by radiation grafting of styrene onto NR [5]. Ono et al have reported the grafting of MMA onto NR by gamma irradiation at a dose of 5 kGy for producing thermoplastic elastomers [4]. The objective of this project is to report the results of studies of radiation graft-copolymerization of methyl methacrylate (MMA) or styrene (St) onto natural rubber latex in order to improve their physico-mechanical properties and evaluation of grafted material using Small-Angle Neutron Scattering through FNCA Project. The grafting degree of MMA and St onto NR increased with the increase of irradiation dose and monomer concentration. The alteration of grafted products structure was determined by IR method. Tensile strength, Shore A hardness, 100% modulus of grafted products increased with the increase of monomer concentration and irradiation dose while elongation at break decreased. The grafted products were characterized by Transmission Electron

  3. Graft Copolymerization of Methyl Methacrylate Monomer onto Starch and Natural Rubber Latex Initiated by Gamma Irradiation

    Directory of Open Access Journals (Sweden)

    S. Iskandar

    2011-04-01

    Full Text Available To obtain the degradable plastic, the graft copolymerization of methyl methacrylate onto starch and natural rubber latex was conducted by a simultaneous irradiation technique. Gamma-ray from cobalt-60 source was used as the initiator. The grafted copolymer of starch-polymethyl methacrylate and the grafted copolymer of natural rubber-polymethyl methacrylate were mixed in the blender, and dried it in the oven. The dried grafted copolymer mixture was then molded using hydraulic press machine. The effect of irradiation dose, composition of the grafted copolymer mixture, film forming condition and recycle effect was evaluated. The parameters observed were tensile strength, gel fraction and soil burial degradability of grafted copolymer mixture. It was found that the tensile strength of grafted copolymer mixture increased by -ray irradiation. Increasing of the grafted copolymer of natural rubber-polymethyl methacrylate content, the gel fraction and tensile strength of the grafted copolymer mixture increased. The tensile strength of the grafted copolymer mixture was increased from 18 MPa to 23 MPa after recycled (film forming reprocessed 3 times. The grafted copolymer mixture was degraded completely after soil buried for 6 months

  4. Irradiation grafting of natural rubber latex with maleic anhydride and its compatibilization of poly(lactic acid)/natural rubber blends

    Science.gov (United States)

    Pongsathit, Siriwan; Pattamaprom, Cattaleeya

    2018-03-01

    Maleic anhydride (MA) is an interesting monomer to be grafted onto natural rubber(NR) due to its potential as a compatibilizer of hydrophobic rubbers and polymers with higher polarity. So far, radiation grafting of MA onto NR in latex state has not been reported. In this study, the grafting of NR with MA in latex state was investigated by exposing the latex to cobalt-60 gamma irradiation at a fixed MA content of 9% and a varied absorbed doses from 2 to 10 kGy. The FTIR spectrometer, 1H NMR spectrometer and gel content analysis have confirmed successful grafting of MA onto NR after irradiation. The grafted NRs were then used to increase the compatibility and the impact property of PLA/NR blends. It was found that the highest impact strength of the blends was achieved when the grafting was carried out at the absorbed dose of 4 kGy.

  5. Deproteinised natural rubber latex grafted poly(dimethylaminoethyl methacrylate) - poly(vinyl alcohol) blend membranes: Synthesis, properties and application.

    Science.gov (United States)

    Jayadevan, Janisha; Alex, Rosamma; Gopalakrishnapanicker, Unnikrishnan

    2018-02-01

    Natural rubber latex was initially deproteinised (DNRL) and then subjected to physicochemical modifications to make high functional membranes for drug delivery applications. Initially, DNRL was prepared by incubating with urea, sodiumdodecylsulphate and acetone followed by centrifugation. The deproteinisation was confirmed by CHN analysis. The DNRL was then chemically modified by grafting (dimethylaminoethyl methacrylate) onto NR particles by using a redox initiator system viz; cumene hydroperoxide/tetraethylenepentamine, followed by dialysis for purification. The grafting was confirmed by dynamic light scattering, Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. The grafted system was blended with a hydrophilic adhesive polymer PVA and casted into membranes. The membranes after blending showed enhanced mechanical properties with a threshold concentration of PVA. The moisture uptake, swelling and water contact angle experiments indicated an increased hydrophilicity with an increased PVA content in the blend membranes. The grafted DNRL possessed significant antibacterial property which has been found to be retained in the blended form. A notable decrease in cytotoxicity was observed for the modified DNRL membranes than the bare DNRL membranes. The in-vitro drug release studies using rhodamine B as a model drug, confirmed the utility of the prepared membranes to function as a drug delivery matrix. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Radiation vulcanization of Philippine natural rubber latex

    International Nuclear Information System (INIS)

    Dela Rosa, A.M.; Abad, L.V.; Sta.Ana-Relleve, L.P.; Tranquilan-Aranilla, C.O.; Pascual, C.L.

    1996-01-01

    The response of Philippine natural rubber latex to irradiation vulcanization and the stability of the irradiated natural rubber latex (INRL) upon storage and aging were investigated. Commercially available high ammonia (HA) concentrated latices obtained from various rubber plantations in Mindanao island were treated with 5 phr of n-butyl acrylate (nBA), and gamma-irradiated at the PNRI 60 Co irradiation facility at a dose rate of 2.57 kGy/hr. Unirradiated cast latex films gave different green strengths which varied from 2-11 MPa. Cast films from INRL exhibited maximum tensile strengths were obtained from cast films with low Mg and high nitrogen contents. Thermal analysis using thermogravimetry (TG) revealed one major decomposition product at 374 o -377 o C. Its rate of decomposition decreased to a minimum at 15 kGy, then increased as radiation dose was increased. This trend correlated well with the tensile strength measurements. The stability of the INRL upon storage and aging is an essential parameter to the rubbe latex industry. For storage studies, INRL was stored for various periods of time. It was found that the pH and total solids content of the stored INRL did not change significantly after 12 months of storage; the MST values remained at above 1000 seconds, and the viscosity decreased with time. The cast films exhibited a decline in tensile strength, modulus 300% , and crosslinking density upon storage. While there were observed changes in the physical properties of the INRL during the storage period, the data indicate that these properties were within values acceptable to the latex industry. Tests on the aging properties of INRL films were undertaken. It was shown that among the chemical antioxidants presently used by the latex industry, TNPP demonstrated the highest antioxidant property, followed by Antage DAHQ and Vulcanox BKF. Our data indicate that the natural rubber latex produced and processed in the Philippines is suited for radiation vulcanization

  7. Natural latex graft in lamellar and penetrating sclerectomies in rabbits Enxerto de látex natural na cicatrização de esclerectomias lamelar e penetrante em coelhos

    Directory of Open Access Journals (Sweden)

    Ivia Carmem Talieri

    2009-09-01

    Full Text Available The objective of study was to investigate the effects of natural latex with 0.1% of polylysine on lamellar and penetrating scleroctomies in rabbits. Two groups of twelve rabbits each (lamellar GI and penetrating GII were studied. Scleral square incisions near the limbus were performed on the left eye of each animal. The latex biomembrane was fixed to the recipient sclera and it covered with a conjunctival flap. The clinical evaluations were followed for 60 days. Aplannation tonometry, binocular indirect ophthalmoscopy and slit-lamp biomicroscopy were performed during evaluation. Bright field microscopy and polarization microscopy were employed. Blepharospasm, graft infection, mucoid ocular discharge and chemosis were not observed in either treatment group. The conjunctival hyperemia varied from moderate to hardly noticeable. The postoperative IOP was not statiscally significant, comparing to the preoperative IOP, for GI and GII. The histopathology by polarization microscopy showed that the neoformed tissue was primarily dependent on adjacent vascularized tissues and was constituted by collagen type III. Both groups presented optimum graft adhesion to the receiving sclera. The natural latex biomembrane with 0.1% polylysine constitutes a new alternative for scleral reconstruction. Furthermore, this is a durable material, easy to obtain and manipulate.Este trabalho teve como objetivo investigar os efeitos do látex natural com polilisina a 0,1% na cicatrização de esclerectomias lamelar e penetrante em coelhos. Foram estudados dois grupos de 12 coelhos (GI - lamelar e GII - penetrante. As esclerectomias foram realizadas no olho esquerdo de cada animal. A biomembrana de látex foi fixada à esclera receptora e foi recoberta com conjuntiva bulbar. As avaliações clínicas foram realizadas durante 60 dias. Para tal, empregaram-se a tonometria de aplanação, a oftalmoscopia indireta binocular e a biomicroscopia em lâmpada de fenda. Realizou-se an

  8. Radiation response of Philippine natural rubber latex

    International Nuclear Information System (INIS)

    Dela Rosa, A.M.; Abad, L.V.; Ana-Relleve, L.S.; Tranquilan-Aranilla, C.; Pascual, C.L.

    1998-01-01

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

  9. Radiation vulcanization of Philippine natural rubber latex

    International Nuclear Information System (INIS)

    Dela Rosa, Alumanda M.; Abad, Lucille V.; Sta, Lorna P.; Ana-Relleve; Tranquilan-Aranilla, Charito O.; Pascual, Cristina L.

    1996-01-01

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

  10. Study on the production of kanvas shoes adhesive from natural rubber latex grafted with methyl methacrylate (NRL-g PMMA) copolymer

    International Nuclear Information System (INIS)

    Utama, Marga; Sudirman; Setyowati, Penny

    2002-01-01

    The optimation condition of radiation copolymerization of MMA into natural rubber latex at the doses of radiation : 5; 7.5 and 10 kGy with concentration of MMA 25; 50; 75; and 100 phr (Part Hundred Ratio of Rubber) expectially and optimazation condition of the adhesive process all the production of canvas shoes have been carried out. The properties of NRL-g-MMA and its rubber such as total solid contain, viscosity, pH, modulus, tensile, strenght, hardnes, elongation at break, and adhesive strenght for producting canvas shoes where evaluated. The at adhesive results show that NRL-g-MMA with the 75 phr of MMA and iradiation dose 5 kGy is adhesive will good stability during storage. The adhesive strenght of shoes its 16-18 N/6mm, more here than SNI 1-0172-1987 with the value 10N/6mm. Besic there is a tendency that adhesive strengt of product shoes at rome temperature (30-50 o C). stronger than at high temperature (100 o C)

  11. Experimental study on the drying of natural latex medical gloves

    Science.gov (United States)

    Chankrachang, Mano; Yongyingsakthavorn, Pisit; Tohsan, Atitaya; Nontakaew, Udomkiat

    2018-01-01

    The purpose of this research was to study latex film drying at 70 °C using a laboratory drying oven. Two different total solid content (TSC) latex compounds, which 45% TSC and 35% TSC were used. The undried latex films were prepared according to the common procedures used in latex gloves manufacturers, that is, by dry coagulant dipping process. The experimental results such as initial moisture content, the amount of moisture and drying time of latex films in each latex compound formula were determined. After that, the results were projected to calculate on the production capacity expand by 1 million piece/day of natural latex medical gloves. Finally, the rate of moisture entering the latex drying oven and the energy consumption of the drying oven were estimated. The results indicated that when the 35% TSC of latex compound was used. The initial moisture content of latex film was higher than 45% TSC of latex compound about 7%. The drying time of 35% TSC was longer than 45% TSC for 2.5 min and consume more energy about 10%. As a result, the 45% TSC latex compound was the better way to saving energy and managing humidity in the production line. Therefore, it was found to very useful to an approximate design length and size of actual of latex drying oven and the rate of moisture entering the oven as well.

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

    International Nuclear Information System (INIS)

    Kulatunge, S.S.; Nadarajah, M.; Kalyani, N.M.V.; Chandralal, H.N.K.K.; Devendra, R.

    1996-01-01

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

  13. Radiation vulcanization of natural rubber latex

    International Nuclear Information System (INIS)

    Wan Manshol bin Wan Zin; Norjanah binti Mohid

    1994-01-01

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

  14. NMR relaxation times of natural rubber latex

    International Nuclear Information System (INIS)

    Harun, S.; Aziz, H.; Basir, Z.

    1994-01-01

    NMR relaxation times T sub 1 and T sub 2 of natural rubber latex have been measured at 25 degree C on a pulsed NMR spectrometer. The work focuses on the variation of the relaxation times with the amount of water content from 0% to 50%. The water content was adjusted by centrifuging and removing a certain amount of water from the sample. The data were analysed using a biexponential fitting procedure which yields simultaneously either T sub 1a and T sub 1b or T sub 2a and T sub 2b. The amount of solid was compared with the known amount of dry rubber content

  15. 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.

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

    African Journals Online (AJOL)

    Introduction. Gloves made of natural rubber latex (NRL) are commonly used by healthcare workers because of their good qualities. However, allergic reactions to latex allergens are still commonly reported. Objective. To measure the concentrations of Hev b 1, Hev b 3, Hev b 5 and Hev b 6.02 allergens in gloves used by a ...

  17. Radiation induced graft copolymerization of acrylonitrile on natural rubber

    International Nuclear Information System (INIS)

    Claramma, N.M.; Mathew, N.M.; Thomas, E.V.

    1989-01-01

    Acrylonitrile graft natural rubber was prepared by initiating the polymerization of acrylonitrile in natural rubber field latex using γ-rays. The reaction was carried out at different rubber-monomer concentrations and the properties of the modified rubbers were compared with those of natural rubber and nitrile rubber. (author)

  18. 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)

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

    International Nuclear Information System (INIS)

    Chirinos, H.; Lugao, A.

    2002-01-01

    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)

  20. Preparation of vinyl acetate grafted natural rubber by irradiation method

    Energy Technology Data Exchange (ETDEWEB)

    Porntrairat, A.; Pattamaprom, C. [Center of Excellence on Natural Rubber Technology, Department of Chemical Engineering, Faculty of Engineering, Thammasat University, Pathumthani 12120 (Thailand)

    2016-03-09

    Improvement in properties of natural rubber could be done by several methods. In this research, gamma radiation technique, which is simple, accurate, easy to control and clean, was applied to enhance the properties of natural rubber (NR) in latex state. The purpose of this research is to study the appropriate condition for preparing grafted natural rubber latex by using irradiation method. Vinyl acetate monomers (VAc) were grafted onto natural rubber latex (NR-g-PVAc) at 0-10 kGys by gamma radiation from Cobalt-60 source at room temperature. Physical properties of grafted natural rubber such as chloroform number, swelling ratio and gel content were measured. The VAc content of NR-g-PVAc was investigated by titration and visualized by FTIR spectroscopy. The FTIR spectra of NR-g-PVAc prepared at 0-10 kGys showed characteristic peaks of the vinyl acetate confirming that VAc could be grafted onto natural rubber molecular chains effectively under appropriate irradiation conditions. From the result, radiation grafting was found to be a useful technique for grafting of vinyl acetate onto natural rubber.

  1. 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)

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

    International Nuclear Information System (INIS)

    Peng Jing; Wang Maolin; Qiao Jinliang; Wei Genshuan

    2005-01-01

    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

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

    International Nuclear Information System (INIS)

    Parra, D. F.

    2006-01-01

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

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

    International Nuclear Information System (INIS)

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

    2013-01-01

    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.

  5. Application of radiation vulcanized natural rubber latex in Indonesia

    International Nuclear Information System (INIS)

    Soebianto, Y.S.; Wiwik Sofiarti; Razzak, M.T.

    1996-01-01

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

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

    International Nuclear Information System (INIS)

    Wan Manshol Wan Zin; Najib Mohamad Zakey; Chai Chee Keong

    2000-01-01

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

  7. Progress in radiation vulcanization of natural rubber latex

    International Nuclear Information System (INIS)

    Makuuchi, Keizo

    2000-01-01

    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)

  8. 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.

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

    International Nuclear Information System (INIS)

    Ma'zam Md Said; Wan Manshol Wan Zin

    1996-01-01

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

  10. Study on grafting of different types of acrylic monomers onto natural rubber by γ-rays

    International Nuclear Information System (INIS)

    Dafader, N.C.; Haque, M.E.; Akhtar, F.; Ahmad, M.U.

    2006-01-01

    A comparative study of various acrylic monomers for grafting onto natural rubber was done. The stability of natural rubber latex (NRL) against coagulum with monomer, mechanical properties of grafted rubbers and percent of grafting were investigated. The NRL with monomers, methylacrylate (MA), ethylacrylate (EA) and n-butylacrylate (n-BA), is unstable but it is stable with methyl methacrylate (MMA), n-butyl methacrylate (BMA) and cyclohexyl methacrylate (CHMA). The mechanical properties and degree of grafting attained a maximum at a total radiation dose of 4 kGy. The values of tensile properties of MMA and CHMA grafted rubbers are almost similar, and higher than those of BMA grafted rubbers. On the other hand, the degree of grafting for CHMA is higher than those of MMA and BMA grafted rubbers. The infrared (IR) spectra of monomer grafted natural rubber were also studied

  11. 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.

  12. Copolymer natural latex in concrete: Dynamic evaluation through energy dissipation of polymer modified concrete

    Science.gov (United States)

    Andayani, Sih Wuri; Suratman, Rochim; Imran, Iswandi; Mardiyati

    2018-05-01

    Portland cement concrete have been used in construction due to its strength and ecomical value. But it has some limitations, such low flexural strength, low tensile strength, low chemical resistant and etc. Due to its limitations in flexural and tensile strength, Portland cement concrete more susceptible by seismic force. There are some methods for improving its limitations. Polymer addition into concrete mixture could be one of solution for improving the flexural and tensile strength, in aiming to get erthquake resistant properties. Also, the eartquake resistant could be achieved by improving energy dissipation capacity. In this research, the earthquake resistant evalution was approached from dynamic evaluation through energy dissipation capacity, after polymer addition as concrete additives. The polymers were natural latex (Indonesian naural resource) grafted with styrene and methacrylate, forming copolymer - natural latex methacrylate (KOLAM) and copolymer - natural latex styrene (KOLAS). They were added into concrete mixture resulting polymer modified concrete. The composition of polymer are 1%, 5% and 10% weight/weight of cement. The higher capacity of energy dissipation will give more capability in either absorbing or dissipating energy, and it was predicted would give better earthquake resistant.. The use of KOLAM gave better performance than KOLAS in energy dissipation capacity. It gave about 46% for addition of 1% w/w compared to Portland cement concrete. But for addition 5% w/w and 10% w/w, they gave about 7% and 5% higher energy dissipation capacity. The KOLAM addition into concrete mixture would reduce the maximum impact load with maximumabout 35% impact load reducing after 1% w/w addition. The higher concentration of KOLAM in concrete mixture, lower reducing of impact load, they were about 4% and 3% for KOLAM 5% and 10%. For KOLAS addition in any compositions, there were no positive trend either in energy dissipation capacity or impact load properties

  13. 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.

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

    International Nuclear Information System (INIS)

    Vo Van Thien; Nguyen Quoc Hien; Keizo Makuuchi; Fumio Yoshii

    2000-01-01

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

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

    OpenAIRE

    H Nabavizade; R Amin

    2007-01-01

    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 descr...

  16. Preparation of irradiated natural rubber latex-styrene copolymer for electrical gloves

    International Nuclear Information System (INIS)

    Made Sumarti Kardha

    2010-01-01

    Research on irradiated natural rubber latex-styrene copolymer to prepare electrical glove have been done. Vulcanization of natural rubber latex (NRL) was done by mixing 2 phr (per hundred of rubber) of normal butyl acrylate (n-BA) emulsion then irradiated with ã-ray "6"0Co at the dose of 30 kGy producing irradiated natural rubber latex (INRL). Natural rubber latex-styrene copolymers (SC) were prepared by mixing NRL and styrene monomer at styrene concentrations of 50 phr, 75 phr, 100 phr, 500 phr and irradiated at the doses of 15 kGy, 30 kGy and 45 kGy, then characterized their latex and film properties to obtain optimum SC of SC50. This optimum SC, SC50 then mixed with IRNL at the weight ratio of 0/100, 30/70, 50/50, 70/30 and 100/0, to produce irradiated natural rubber latex-styrene copolymer. The properties of copolymer rubber films made by dipping process i.e., % conversion, total solid content, latex viscosity, tensile strength, modulus 300 %, elongation at break, electrical resistance and dielectric constant were then characterized. Characterization result showed that (INRL-SC50) with 50/50 ratio irradiated at the dose of 30 kGy, have % conversion of 80.93 %, electrical resistivity of 1.73 x 10"1"4 Ohm cm and dielectric constant of 2.76 which fulfill the requirement as material for electrical gloves. (author)

  17. Ciprofloxacin release using natural rubber latex membranes as carrier.

    Science.gov (United States)

    Dias Murbach, Heitor; Jaques Ogawa, Guilherme; Azevedo Borges, Felipe; Romeiro Miranda, Matheus Carlos; Lopes, Rute; Roberto de Barros, Natan; Guedes Mazalli, Alexandre Vinicius; Gonçalves da Silva, Rosângela; Ferreira Cinman, José Luiz; de Camargo Drago, Bruno; Donizetti Herculano, Rondinelli

    2014-01-01

    Natural rubber latex (NRL) from Hevea brasiliensis is easily manipulated, low cost, is of can stimulate natural angiogenesis and cellular adhesion, is a biocompatible, material and presents high mechanical resistance. Ciprofloxacin (CIP) is a synthetic antibiotic (fluoroquinolone) used in the treatment of infection at external fixation screws sites and remote infections, and this use is increasingly frequent in medical practice. The aim of this study was to develop a novel sustained delivery system for CIP based on NRL membranes and to study its delivery system behavior. CIP was found to be adsorbed on the NRL membrane, according to results of energy dispersive X-ray spectroscopy. Results show that the membrane can release CIP for up to 59.08% in 312 hours and the mechanism is due to super case II (non-Fickian). The kinetics of the drug release could be fitted with double exponential function X-ray diffraction and Fourier transform infrared (FTIR) spectroscopy shows some interaction by hydrogen bound, which influences its mechanical behavior.

  18. Effect of gamma radiation dose and sensitizer on the physical properties of irradiated natural rubber latex

    International Nuclear Information System (INIS)

    Komgrit, R.; Thawat, C.; B, Tripob; Wirach, T.

    2009-07-01

    Full text: The vulcanization of natural rubber latex can be induced by gamma radiation, which enhances cross-linking within the rubber matrix. The purpose of this research is to investigate the effect of gamma radiation dose and sensitizers on the physical properties of irradiated natural rubber. Three sensitizers n-butyl acrylate (n-B A), tetrachloroethylene (C 2 Cl 4 ) and trichloromethane (CHCl 3 ) were mixed with natural rubber latex before irradiation with gamma ray dose varied from 14 to 22 kGy. Results showed that the mixture of three sensitizers with specific ratios effectively induced the cross-linking of natural rubber latex. The cross-linking ratio and improved physical properties increased with increasing gamma dose. Therefore, the mixture ratios of n-B A, C 2 Cl 4 and CHCl 3 have shown to be a critical parameter in the vulcanization of natural rubber latex by gamma radiation

  19. Silver nanoparticles delivery system based on natural rubber latex membranes

    International Nuclear Information System (INIS)

    Guidelli, Éder José; Kinoshita, Angela; Ramos, Ana Paula; Baffa, Oswaldo

    2013-01-01

    The search for new materials for biomedical applications is extremely important. Here, we present results on the performance of a silver nanoparticles delivery system using natural rubber latex (NRL) as the polymeric matrix. Our aim was to obtain an optimized wound dressing by combining materials with potential healing action. The synthesis of silver nanoparticles and their characterization by UV–Vis spectroscopy, transmission electron microscopy, zeta potential, dynamic light scattering, and Fourier transform infrared spectroscopy (FTIR) are depicted. The NRL membranes are good matrix for silver nanoparticles and allow for their gradual release. The release of 30 nm silver nanoparticles by the NRL membranes depends on their mass percentage in NRL membranes. The total concentration of AgNP released by the NRL membranes was calculated. The AgNP attached to the cis-isoprene molecules in the NRL matrix remain attached to the membrane (∼0.1 % w/w). So, only the AgNP bound to the non-rubber molecules are released. FTIR spectra suggest that non-rubber molecules, like aminoacids and proteins, associated with the serum fraction of the NRL may be attached to the surfaces of the released nanoparticles, thereby increasing the release of such molecules. The released silver nanoparticles are sterically stabilized, more stable and well dispersed. Because the serum fraction of the NRL is responsible for the angiogenic properties of the matrix, the silver nanoparticles could increment the angiogenic properties of NRL. This biomaterial has desirable properties for the fabrication of a wound dressing with potential healing action, since it combines the angiogenic and antibacterial properties of the silver nanoparticles with the increased angiogenic properties of the NRL.Graphical AbstractThe AgNP attached to the cis-isoprene molecules remain in the NRL matrix and only the AgNP bound to the non-rubber molecules (NRL serum fraction) are released. The released AgNP are sterically

  20. Silver nanoparticles delivery system based on natural rubber latex membranes

    Energy Technology Data Exchange (ETDEWEB)

    Guidelli, Eder Jose, E-mail: ederguidelli@gmail.com [Universidade de Sao Paulo/FFCLRP-DF (Brazil); Kinoshita, Angela [Universidade do Sagrado Coracao (Brazil); Ramos, Ana Paula [Universidade de Sao Paulo/FFCLRP-DQ (Brazil); Baffa, Oswaldo [Universidade de Sao Paulo/FFCLRP-DF (Brazil)

    2013-04-15

    The search for new materials for biomedical applications is extremely important. Here, we present results on the performance of a silver nanoparticles delivery system using natural rubber latex (NRL) as the polymeric matrix. Our aim was to obtain an optimized wound dressing by combining materials with potential healing action. The synthesis of silver nanoparticles and their characterization by UV-Vis spectroscopy, transmission electron microscopy, zeta potential, dynamic light scattering, and Fourier transform infrared spectroscopy (FTIR) are depicted. The NRL membranes are good matrix for silver nanoparticles and allow for their gradual release. The release of 30 nm silver nanoparticles by the NRL membranes depends on their mass percentage in NRL membranes. The total concentration of AgNP released by the NRL membranes was calculated. The AgNP attached to the cis-isoprene molecules in the NRL matrix remain attached to the membrane ({approx}0.1 % w/w). So, only the AgNP bound to the non-rubber molecules are released. FTIR spectra suggest that non-rubber molecules, like aminoacids and proteins, associated with the serum fraction of the NRL may be attached to the surfaces of the released nanoparticles, thereby increasing the release of such molecules. The released silver nanoparticles are sterically stabilized, more stable and well dispersed. Because the serum fraction of the NRL is responsible for the angiogenic properties of the matrix, the silver nanoparticles could increment the angiogenic properties of NRL. This biomaterial has desirable properties for the fabrication of a wound dressing with potential healing action, since it combines the angiogenic and antibacterial properties of the silver nanoparticles with the increased angiogenic properties of the NRL.Graphical AbstractThe AgNP attached to the cis-isoprene molecules remain in the NRL matrix and only the AgNP bound to the non-rubber molecules (NRL serum fraction) are released. The released AgNP are

  1. Natural rubber latex: past, present and future in Latin America

    International Nuclear Information System (INIS)

    Lugao, A.B.; Miranda, A.; Mindrisz, A.C.; Andrade e Silva, L.G. de

    1996-01-01

    The origin of the Hevea braziliensis tree was the Amazonian region in South America, particularly the Brazilian jungle. The rubber expansion at the end of 9th century brought prosperity and determined the borders of Amazonian countries. In spite of that, the Brazilian government has failed in establishing a successful policy for improving the NR production in the jungle. However, rubber plantations were successfully introduced recently near marginal areas of the humid forest in the Amazon due to the absence of the fungus Microcyclos ulei. Both, extraction of wild rubber and plantation have a key role in the maintenance of the forest health. The market for dipping products is small but is growing very fast and is expected to follow this pattern as the sanitary conditions are improved by the health authority. The history of the Brazilian NR products industry is contemporary and is based on the policy of market protection and on the lack of investments due to extremely high interest rates. As a result, the industry was not competitive. It was concluded that, in order to cope with the future challenge, the industry is required to invest in very modern technologies to produce first class goods with international acceptance. Latin America would follow the world trend for nitrosamine and protein free products. The radiation vulcanization of natural rubber latex could prove itself as a profitable solution and not only a quality solution. It was also concluded that both wild rubber and rubber plantations in Brazil have their future coupled with the future of a regional dipping industry. Moreover, the buildup of the dipping industry will be beneficial to the protection of the humid forest and the recovery of degraded areas

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

    International Nuclear Information System (INIS)

    Canavel, V.

    1993-01-01

    The natural rubber latex was vulcanized by gamma rays and electrons beam, in the presence and absence of sensitizer at room temperature. The sensitizers were the following; n-butyl acrylate (n-BA) / t-butyl hydroperoxide (t-B H) / KOH, C Cl 4 / potassium laurate and n-BA / KOH. The studied antioxidants, Irganox 1520, Vulcanox SP and Vulcanox BKF, were added to the latex after irradiation. Among the studied antioxidants in function of tensile strength (TS) after the aging of rubber plates, the Irganox was the best efficient on the gamma vulcanization in the presence of n-BA/t-B H/KOH, because only 0,20 p hr is enough to obtain the greatest increase of TS, that was 34%, 12 MPa to 16 MPa. The formulating method of latex with the sensitizer constituted the 3,0 p hr of n-BA/ 0,1 p hr of t-B H and 0,2 p hr of KOH, was evaluated respecting the TS of rubber plates. The electrons beam vulcanization produces the greatest reversible perturbance in the colloidal stability of latex after irradiation caused by radiolytic species absorption that promotes the increase of particle size. The antioxidant also contributes to reversible destabilization of gamma irradiated latex, because it is also adsorbed by particles surface. The relation between the latex viscosity and the TS of respective rubber plates is reverse, showing the latex stability affects the quality of rubber goods. (author)

  3. Test trial radiation vulcanization of natural rubber latex in Jakarta Indonesia

    International Nuclear Information System (INIS)

    Devendra, R.; Kulatunge, S.S.; Chandralal, H.N.K.K.; Kalyani, N.M.V.; Seneviratne, J.; Wellage, S.

    1994-01-01

    Radiation vulcanization of natural rubber latex (RVNRL) can be used to make large quantities of specially stabilized latex. It is possible to obtain RVNRL films of tensile strength over 25 MPa. The films could be either coagulant dipped or cast. It is very important to determine the correct radiation dose which gives the maximum tensile strength. Cross linking density or prevulcanized relax modulus (PRM) at 100% is a reliable property to control the prevulcanization

  4. 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.

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

    International Nuclear Information System (INIS)

    Machi, Sueo

    1990-01-01

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

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

    International Nuclear Information System (INIS)

    Feroza Akhtar; Keizo Makuuchi; Fumio Yoshii

    1996-01-01

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

  7. Extractable protein of radiation vulcanized natural rubber latex

    International Nuclear Information System (INIS)

    Soebianto, Y.S.; Upul, R.M.; Makuuchi, K.; Yoshii, F.; Kume, T.

    2000-01-01

    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)

  8. 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)

  9. Extractable protein of radiation vulcanized natural rubber latex

    International Nuclear Information System (INIS)

    Soebianto, Y.S.; Ratnayake, U.M.; Makuuchi, Keizo; Yoshii, Fumio; Kume, Tamikazu

    2000-01-01

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

  10. Radiation grafting on natural films

    Science.gov (United States)

    Lacroix, M.; Khan, R.; Senna, M.; Sharmin, N.; Salmieri, S.; Safrany, A.

    2014-01-01

    Different methods of polymer grafting using gamma irradiation are reported in the present study for the preparation of newly functionalized biodegradable films, and some important properties related to their mechanical and barrier properties are described. Biodegradable films composed of zein and poly(vinyl alcohol) (PVA) were gamma-irradiated in presence of different ratios of acrylic acid (AAc) monomer for compatibilization purpose. Resulting grafted films (zein/PVA-g-AAc) had their puncture strength (PS=37-40 N mm-1) and puncture deformation (PD=6.5-9.8 mm) improved for 30% and 50% PVA in blend, with 5% AAc under 20 kGy. Methylcellulose (MC)-based films were irradiated in the presence of 2-hydroxyethyl methacrylate (HEMA) or silane, in order to determine the effect of monomer grafting on the mechanical properties of films. It was found that grafted films (MC-g-HEMA and MC-g-silane) using 35% monomer performed higher mechanical properties with PS values of 282-296 N mm-1 and PD of 5.0-5.5 mm under 10 kGy. Compatibilized polycaprolactone (PCL)/chitosan composites were developed via grafting silane in chitosan films. Resulting trilayer grafted composite film (PCL/chitosan-g-silane/PCL) presented superior tensile strength (TS=22 MPa) via possible improvement of interfacial adhesion (PCL/chitosan) when using 25% silane under 10 kGy. Finally, MC-based films containing crystalline nanocellulose (CNC) as a filling agent were prepared and irradiated in presence of trimethylolpropane trimethacrylate (TMPTMA) as a grafted plasticizer. Grafted films (MC-g-TMPTMA) presented superior mechanical properties with a TS of 47.9 MPa and a tensile modulus (TM) of 1792 MPa, possibly due to high yield formation of radicals to promote TMPTMA grafting during irradiation. The addition of CNC led to an additional improvement of the barrier properties, with a significant 25% reduction of water vapor permeability (WVP) of grafted films.

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

    Directory of Open Access Journals (Sweden)

    H Nabavizade

    2007-07-01

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

  12. Analysis of Aqueous Extractable Protein in Radiation Pre vulcanized Natural Rubber Latex (RVNRL) And Sulphur Pre vulcanized Natural Rubber Latex (SVNRL)

    International Nuclear Information System (INIS)

    Sofian Ibrahim; Mohd Noor Wadi Mat Lazim; Syuhada Ramli; Keong, C.C.; Khairul Hisyam Mohd Yusof; Muhammad Saiful Omar; Najib Mohd Zakey; Hafizuddin Maseri; Noor Hasni Mohd Ali

    2015-01-01

    The use of radiation do not only produces Radiation Pre vulcanized Natural Rubber Latex (RVNRL) that can be used for the production of nitrosamines free products, moreover, RVNRL also able to exclude type IV allergy that caused by high protein content in the products. Leaching water from production of finger coat from RVNRL and Sulphur Pre vulcanized Natural rubber Latex (SVNRL) has been collected. Extractable protein content from water samples measured according to the test protocol ASTM D5712-2010. Water from leaching process of finger coat made from RVNRL showed a higher protein content than SVNRL. This explains why RVNRL based products contain very low protein content and thus reduce the risk of Type IV allergy. (author)

  13. Mechanism of n-butyl acrylate sensitization action in radiation vulcanization of natural rubber latex

    International Nuclear Information System (INIS)

    Sabharwal, S.; Chaudhari, C.V.; Bhardwaj, Y.K.; Majali, A.B.; Das, T.N.

    1996-01-01

    In order to understand the role of n-butyl acrylate (nBA) in radiation vulcanization of natural rubber latex, pulse radiolysis technique has been utilized to study the reactions of the transient species produced by reaction of OH . , e- aq and H . atoms with nBA in aqueous solutions. The results show that transients produced by reaction of e- aq with nBA alone are capable of propagating the polymerization reaction and enhance the vulcanization process. These results have been further confirmed by studying the effect of electron scavengers on the vulcanization behaviour of natural rubber latex in presence of nBA. (author). 3 refs., 3 figs

  14. Gamma irradiator design concepts for radiation vulcanisation of natural rubber latex

    International Nuclear Information System (INIS)

    Aggarwal, K.S.; Muralidharan, P.; Apte, M.G.; Kalurkar, A.R.; Shah, B.M.

    1990-01-01

    Radiation vulcanisation of natural rubber latex (NRL) is a new and yet unproven technology and one which involves undefined problems of consumer acceptance and high degree of radiation risk. Therefore, the designer should take care that the initial capital cost of the plant is as low as possible to keep the unit processing cost low during the initial lean period of the product requirement by the market. Three irradiators to process natural rubber latex have been designed as per capacity requirement of the user. Their salient features are described. (author). 2 tabs., 24 figs

  15. Mechanical and morphological properties of kenaf powder filled natural rubber latex foam

    Energy Technology Data Exchange (ETDEWEB)

    Karim, Ahmad Fikri Abdul, E-mail: a.fikri-89@yahoo.com; Ariff, Zulkifli Mohamad [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Pulau Pinang (Malaysia); Ismail, Hanafi [Cluster for Polymer Composites (CPC), Science and Engineering Research Centre, Engineering Campus, Universiti Sains Malaysia,14300 Nibong Tebal, Pulau Pinang (Malaysia)

    2015-07-22

    This research is carried out by incorporate kenaf powder with natural rubber latex (NRL) compound and is foamed to make natural rubber latex foam (NRLF) by using a well known technique called Dunlop method. Different loading of kenaf powder was added to NRL compound and was foamed to make NRLF. The tensile properties, and morphology of kenaf filled NRLF was studied. Increase in kenaf loading reduced the tensile strength and elongation at break and of a compound. Modulus at 100% elongation of the compound increased with increased in filler loading. The morphological and micro structural characterization has been performed by using scanning electron microscopy (SEM)

  16. Mechanical and morphological properties of kenaf powder filled natural rubber latex foam

    International Nuclear Information System (INIS)

    Karim, Ahmad Fikri Abdul; Ariff, Zulkifli Mohamad; Ismail, Hanafi

    2015-01-01

    This research is carried out by incorporate kenaf powder with natural rubber latex (NRL) compound and is foamed to make natural rubber latex foam (NRLF) by using a well known technique called Dunlop method. Different loading of kenaf powder was added to NRL compound and was foamed to make NRLF. The tensile properties, and morphology of kenaf filled NRLF was studied. Increase in kenaf loading reduced the tensile strength and elongation at break and of a compound. Modulus at 100% elongation of the compound increased with increased in filler loading. The morphological and micro structural characterization has been performed by using scanning electron microscopy (SEM)

  17. Effects of radio sensitizers in the vulcanization of natural rubber latex induced by gamma radiation

    International Nuclear Information System (INIS)

    Souza, A. de; Canavel, V.; Araujo, S.C. de; Guedes, S.M.L.

    1992-01-01

    The effect of C Cl 4 and n-butyl acrylate as a sensitizer for radiation vulcanization of 60% DRC natural rubber latex with gamma rays, was studied relating tensile strength of vulcanized latex. The vulcanization dose is 200 kGy for natural rubber latex and it decreases to 40 kGy and to 9 kGy in the presence of C Cl 4 / potassium laureate and n-butyl acrylate / t-butyl hydroperoxide, respectively. The H 2 O 2 as a co-sensitizer does not change the efficiency of the combination of these sensitizers. The IV spectra show the formation of C=O after the irradiation as consequence of oxidation reactions. (author)

  18. Trialed production of low protein irradiated natural rubber latex in factory scale by gamma irradiation technique

    International Nuclear Information System (INIS)

    Utama, Marga; Herwinarni, S.; Halik, H.M.; Siswanto; Suharyanto; Syamsu, Y.; Handoko, B.

    2006-01-01

    Four tons fresh field natural rubber latex (FNRL) with total solid content 30% were added with 2 phr (part hundred ratio of rubber) normal butyl acrylate (nBA) then irradiated by gamma rays at 25 kGy. The irradiated FNRL was centrifuged, then the properties of irradiated centrifuged natural rubber latex (INRL) and its film were measured before and after storage for 5 months. It is found that the INRL is stable latex during storage in 5 months, with lowest protein, and free nitrosamine content. The tensile strength of INRL film was 24-27 MPa, and modulus 600% was 1,5-2,0 MPa, elongation at break was 900%, and hardness was 27-29 Shore A, while the extractable protein content less than 100 μg/g. (author)

  19. 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)

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

    International Nuclear Information System (INIS)

    Ribeiro, Jaqueline Alves; Rosa, Suelia Rodrigues Fleury; Leite, Cicilia Raquel Maia; Vasconcelos, Claudio Lopes; Soares, Joao Maria

    2017-01-01

    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)

  1. Cost evaluation of radiation vulcanization of natural rubber latex

    International Nuclear Information System (INIS)

    Makuuchi, K.

    2003-01-01

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

  2. Radiation grafting on natural films

    International Nuclear Information System (INIS)

    Lacroix, M.; Khan, R.; Senna, M.; Sharmin, N.; Salmieri, S.; Safrany, A.

    2014-01-01

    Different methods of polymer grafting using gamma irradiation are reported in the present study for the preparation of newly functionalized biodegradable films, and some important properties related to their mechanical and barrier properties are described. Biodegradable films composed of zein and poly(vinyl alcohol) (PVA) were gamma-irradiated in presence of different ratios of acrylic acid (AAc) monomer for compatibilization purpose. Resulting grafted films (zein/PVA-g-AAc) had their puncture strength (PS=37–40 N mm −1 ) and puncture deformation (PD=6.5–9.8 mm) improved for 30% and 50% PVA in blend, with 5% AAc under 20 kGy. Methylcellulose (MC)-based films were irradiated in the presence of 2-hydroxyethyl methacrylate (HEMA) or silane, in order to determine the effect of monomer grafting on the mechanical properties of films. It was found that grafted films (MC-g-HEMA and MC-g-silane) using 35% monomer performed higher mechanical properties with PS values of 282–296 N mm −1 and PD of 5.0–5.5 mm under 10 kGy. Compatibilized polycaprolactone (PCL)/chitosan composites were developed via grafting silane in chitosan films. Resulting trilayer grafted composite film (PCL/chitosan-g-silane/PCL) presented superior tensile strength (TS=22 MPa) via possible improvement of interfacial adhesion (PCL/chitosan) when using 25% silane under 10 kGy. Finally, MC-based films containing crystalline nanocellulose (CNC) as a filling agent were prepared and irradiated in presence of trimethylolpropane trimethacrylate (TMPTMA) as a grafted plasticizer. Grafted films (MC-g-TMPTMA) presented superior mechanical properties with a TS of 47.9 MPa and a tensile modulus (TM) of 1792 MPa, possibly due to high yield formation of radicals to promote TMPTMA grafting during irradiation. The addition of CNC led to an additional improvement of the barrier properties, with a significant 25% reduction of water vapor permeability (WVP) of grafted films. - Highlights: • Irradiation of zein

  3. Effect of cellulose nanocrystals from corn cob with dispersion agent polyvinyl pyrrolidone in natural rubber latex film after aging treatment

    Science.gov (United States)

    Harahap, H.; Ridha, M.; Halimatuddahliana; Taslim; Iriany

    2018-02-01

    This study about the resistance of natural rubber latex films using nanocrystals cellulose filler from corn cob waste by aging treatment. Corn cob used as organic filler composed of cellulose, hemicellulose, and lignin. Each component has a potential for reuse, such as cellulose. Cellulose from corn cob has potential application as a filler prepared by hydrolysis process using a strong acid. The producing of natural rubber latex films through coagulant dowsing process. This research started with the pre-vulcanization process of natural rubber latex at 70 °C and followed by process of vulcanization at 110 °C for 20 minutes. Natural rubber latex films that have been produced continued with the aging treatment at 70 °C for 168 hours. The mechanical properties of natural rubber latex films after aging treatment are the tensile strength, elongation at break, M100 and M300 have performed.

  4. Radiation vulcanization of natural rubber latex using 250 keV electron beam machine

    Energy Technology Data Exchange (ETDEWEB)

    Chirinos, H.; Yoshii, F.; Makuuchi, K.; Lugao, A. E-mail: ablugao@net.ipen.br

    2003-08-01

    The sensitized radiation vulcanization of natural rubber latex has been carried out with 250 keV electrons. Latex was irradiated over a range of the beam current from 5 to 20 mA in the presence of sensitizers like the n-butyl acrylate (n-BA). The vulcanization dose decreases with increasing beam current condition. The rate of vulcanization (R{sub vul}) depends on the beam current (I) as given by the equation R{sub vul}=kI{sup 0.6}.

  5. 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.

  6. Radiation Vulcanization of Natural Rubber Latex (RVNRL): A Potential Material for Nuclear Power Plant Gloves

    International Nuclear Information System (INIS)

    Pairu Ibrahim; Wan Manshol Wan Zain; Keong, C.C.; Mohd Noorwadi Mat Lazim

    2011-01-01

    Radiation vulcanization of natural rubber latex has great potential for the production of nuclear power plant gloves due to its low ash and mineral content. And this is in-line with the role played by Malaysian Nuclear Agency as Technical Supporting Organization for Nuclear Power Program. This paper discussed the evaluation done to determine ash content in RVNRL and SVNRL films. Both samples were prepared using casting technique and the properties were compared. Films prepared from raw latex without any vulcanizing agent were regarded as a control. (author)

  7. Extractable proteins from electron beam (EB) irradiated natural rubber (NR) latex

    International Nuclear Information System (INIS)

    Feroza Akhtar; Fumio Yoshii; Keizo Makuuchi

    1996-01-01

    The protein assay of natural rubber latex (NRL) vulcanized by low energy electron beam (EB, 300 keV, 30 mA) has been carried out using Bicinchoninic acid (BCA) reagent. Extractable protein in irradiated latex film was determined by measuring the absorption of colored solution at 562 nm using UV spectrometer. The effect of various radiation doses on the extractable protein content of NRL was investigated. It was ,found that the quantities of extractable protein increases with radiation dose. When compared with ,gamma-ray irradiated samples the same trend was observed. Electron beam irradiated latex films are leached in 1% (ammonia water for various lengths of time. From the results it was established that within 2 hours of leaching in ammonia water most of the extractable protein (96%) were removed from rubber film

  8. Extraction and comparison of proteins from natural rubber latex by conventional and ionizing radiation methods

    International Nuclear Information System (INIS)

    Rogero, Sizue O.; Spencer, Patrick J.; Campos, Vania E.; Lusvarghi, Fabio M.; Higa, Olga Z.

    1997-01-01

    Several proteins in natural rubber latex (NRL) have been assigned to be significant allergens. It is known that proteins submitted to ionizing radiation suffer denaturation and immunochemical modification resulting in low antigenic reactivity. The aim of this study was to extract and compare water extractable proteins from NRL films vulcanized by conventional and by ionizing radiation methods. SDS-polyacrylamide gel electrophoresis (SDS--PAGE) and high pressure liquid chromatography (HPLC) showed a diffuse protein band of about 14 KDa, which we believe is rubber elongation factor (REF), in both eluates, but smaller in latex film vulcanized by ionizing radiation. REF has been suggested to be a major latex allergen. These data suggest that ionizing radiation vulcanization could be an useful method for the production of NRL goods with low antigenicity. (author). 8 refs., 2 figs., 1 tab

  9. Evaluation of peptides release using a natural rubber latex biomembrane as a carrier.

    Science.gov (United States)

    Miranda, M C R; Borges, F A; Barros, N R; Santos Filho, N A; Mendonça, R J; Herculano, R D; Cilli, E M

    2018-05-01

    The biomembrane natural (NRL-Natural Rubber Latex), manipulated from the latex obtained from the rubber tree Hevea brasiliensis, has shown great potential for application in biomedicine and biomaterials. Reflecting the biocompatibility and low bounce rate of this material, NRL has been used as a physical barrier to infectious agents and for the controlled release of drugs and extracts. The aim of the present study was to evaluate the incorporation and release of peptides using a latex biomembrane carrier. After incorporation, the release of material from the membrane was observed using spectrophotometry. Analyses using HPLC and mass spectroscopy did not confirm the release of the antimicrobial peptide [W 6 ]Hylin a1 after 24 h. In addition, analysis of the release solution showed new compounds, indicating the degradation of the peptide by enzymes contained in the latex. Additionally, the release of a peptide with a shorter sequence (Ac-WAAAA) was evaluated, and degradation was not observed. These results showed that the use of NRL as solid matrices as delivery systems of peptide are sequence dependent and could to be evaluated for each sequence.

  10. 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

  11. Radiation prevulcanized natural rubber latex: Cytotoxicity and safety evaluation on animal

    International Nuclear Information System (INIS)

    Keong, C C; Zin, W M Wan; Ibrahim, P; Ibrahim, S

    2010-01-01

    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

  12. The influence of temperature and reaction time in the degradation of natural rubber latex

    International Nuclear Information System (INIS)

    Siti Zaleha Isa; Rosiyah Yahya; Aziz Hassan; Mohd Tahir

    2007-01-01

    Liquid natural rubber (LNR /LENR) should be considered as a new material instead of a new type of rubber though they have the same configuration as the rubber used. In this work, thermal degradation of natural rubber latex was carried out to obtain LNR/LENR by varying the reaction time at different temperatures. The degraded polymers were characterized structurally using FTIR and NMR spectroscopies and the average molecular weights were determined by membrane-osmometry and viscometry. (author)

  13. Study on preparation of new antioxidants for radiation vulcanized natural rubber latex product. Antioxidant from keratin

    International Nuclear Information System (INIS)

    Nguyen Quoc Hien; Nguyen Van Toan; Vo Tan Thien; Le Hai

    2000-01-01

    The thermo-oxidative aging resistance of radiation vulcanization of natural rubber latex (RVNRL) products should be adequately by using suitable antioxidants or new kind of effective antioxidant. This work presents the results of preparation of natural antioxidant from hair keratin. Characteristics and effectiveness of resultant antioxidant are also presented. The results obtained indicates that antioxidant made from hair keratin is safe and effective for rubber products from RVNRL. (author)

  14. Production Of Hollow Toy Product From Radiation Pre vulcanized Natural Rubber Latex (RVNRL) By Using Casting And Moulding Technique

    International Nuclear Information System (INIS)

    Mohd Noorwadi Mat Lazim; Sofian Ibrahim; Muhammad Saiful Omar

    2013-01-01

    Hollow toy products are very synonym to the child from the age of months since it able to stimulating each of their sense such as sight, hearing, taste, touch and smell. Most of hollow toy products are made from natural rubber latex by using moulding and casting technique. The moulding and casting technique is a manufacturing process by pored liquid latex into a mould, which contain cavity of the desired shape. The mould made from plaster of Paris able to absorbs water from latex meanwhile the presence of calcium ions from plaster of Paris will tend to diffuse into latex thus promote formation of deposit on surface of cavity mould. To improve the quality and safety of hollow toy product made from latex, Radiation Pre vulcanized Natural Rubber Latex (RVNRL) has been identified to be used because it can fulfill the standard requirement for latex and also due to its special abilities such as lower modulus (soft latex products), nitrosamines free, low in nitrosatables, free from chemical accelerators induced allergies and better biodegradability. This paper identify the problem appears from the process of making hollow toy products from RVNRL by using moulding and casting technique. (author)

  15. 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%.

  16. Radiation vulcanization of natural rubber latex with low energy accelerator-II

    Energy Technology Data Exchange (ETDEWEB)

    Haque, Md. 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, Dept. of Biological and Chemical Engineering, Kiryu, Gunma (Japan)

    2002-03-01

    The natural rubber latex (NRL) was radiation vulcanized under a low energy electron accelerator. Accelerating voltage and maximum beam current of this accelerator are 250 kV and 10 mA respectively. Irradiation was carried out in a reaction vessel with constant stirring. The capacity of the vessel is 18 liters. Radiation vulcanization accelerators (RVA) were normal butyl acrylate (n-BA) and nonane-diol-diacrylate (NDDA). NDDA has no bad smell like that of n-BA. 20 minutes irradiation time is enough to vulcanize 14 liters of latex when 5 phr RVA (both types) are used. Maximum of {approx}30 MPa tensile strength was obtained with 5 phr NDD-A. However the remained NDDA is difficult to remove due to high molecular weight. Water-extractable proteins content was determined in dipped films for various leaching conditions without and with additive (polyvinyl alcohol, PVA). Water extractable proteins content is reduced to {<=} 41 by adding 5 phr PVA and leaching for 8 hours. The tackiness of the dipped films is reduced to 0.1 from 9 gf by mixing 6 phr PVA with the irradiated latex. Hand gloves (surgical and examination) were successfully produced from the irradiated latex. (author)

  17. 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.

  18. The effect of proteins on the aging properties of radiation vulcanized natural rubber latex

    International Nuclear Information System (INIS)

    Abad, L.V.

    1993-01-01

    The effect of natural rubber latex (NRL) proteins on the aging properties of NRL films was investigated. SDS-PAGE electrophoresis of the rubber proteins in NRL (Sri-Lanka) indicated a total of 18 proteins. A sharp decrease in tensile strength was observed after aging when NRL films were leached in 1% NH 4 OH. However, when these films were soaked in ethanol prior to leaching, the aging properties approximated those of the unleashed samples. Electrophoretic analysis of the proteins present in the NH 3 extracts of leached RVNRL films showed a high concentration of the protein herein. This protein was not found in the NH 3 extracts of ethanol soaked films. NRL proteins were shown to decelerate the aging process of Radiation Vulcanized Natural Rubber Latex (RVNRL) films. Among the proteins, herein exhibited good anti-aging properties. The hydrolyzates from NR proteins also enhanced considerably the aging properties of RVNRL. (auth.). 8 refs.; 40 figs.; 30 tabs

  19. Safety Evaluation Test on Human for Radiation Pre vulcanised Natural Rubber Latex (RVNRL)

    International Nuclear Information System (INIS)

    Pairu Ibrahim; Wan Manshol Wan Zain; Chai, Chee Keong; Sofian Ibrahim; Saadiah Sulaiman; Sharifah Ismail

    2010-01-01

    This paper discussed about clinical test conducted to determine safety evaluations on human for latex examination gloves and latex films made from Radiation Vulcanized Natural Rubber Latex (RVNRL). Two types of test were being adopted which are i) Modified Draize-95 test and ii) Patch Test on Sensitized Individuals. Modified Draize-95 test was conducted on 200 non-sensitized human subjects and Patch Test on Sensitized Individuals was conducted on 25 individuals who are allergic to the defined major chemical sensitizer presents in natural rubber product. It was found that Modified Draize-95 test has prove that there is no clinical evidence on the presence of residual chemical additives at the level that may induce Type IV allergy in the un sensitized general user population in the RVNRL gloves. Meanwhile Patch Test on Sensitized Individuals has proved that the patch test conducted using the test article on 25 individuals who are allergic to the defined major chemical sensitizers present in natural rubber products, thiuram, carbamates or thiazoles produced a negative response, meeting the pre requirement for the claim of reduced reaction-inducing potential. (author)

  20. n-BA/KOH/t-BHP behaviour in the natural rubber latex vulcanization by gamma rays

    International Nuclear Information System (INIS)

    Souza, A. de.

    1994-01-01

    Natural rubber latex was vulcanized in the absence and in the presence of sensitizer (S), with gamma ray from 60 Co source, panoramic type, at the dose rate range of 1,20-1,33 kGy/h. The components of used S were n-butyl acrylate (n-BA), the KOH as stabilizer and t-butyl hydroperoxide (t-BHP) as co-S. The purpose of this work was to study the efficiency and the behaviour of each component of S in the irradiated latex crosslinking by tensile strength (T b ), volume fraction and permanent set. In the absence of S occur straight crosslinking between macromolecular adjacent radicals. IN the presence of S, the n-BA participates in the crosslinking through acrylic bridges between macromolecules. (author)

  1. The role of proteins on the thermal oxidative aging of radiation vulcanized natural rubber latex

    International Nuclear Information System (INIS)

    Abad, L.V.; Rosa, A. de la; Keizo Makuuchi; Fumio Yoshii

    1996-01-01

    The effect of Hevea latex proteins on the aging properties of radiation vulcanized natural rubber latex (RVNRL) was investigated. Unpurified RVNRL films exhibited better aging properties than the purified RVNRL films. A sharp decrease in tensile strength was observed after aging when RVNRL films were leached in 1% NH sub 4 OH. However, when these films were soaked in ethanol prior to leaching, the aging properties approximated those of the unleached samples. Kjeldahl and FT-IR analyses of the leached and unleached RVNRL films indicated a higher protein content for both the unleached and ethanol-soaked films than for leached films. Electrophoretic analysis of the proteins present in the NH, extracts of leached RVNRL films showed a high concentration of hevein. This protein was not found in the ATH, extracts of ethanol soaked films. Hevein was shown to improve the aging properties of RVNRL

  2. Natural membranes of Hevea brasiliensis latex as delivery system for Casearia sylvestris leaf components

    Directory of Open Access Journals (Sweden)

    Flávio A. Carvalho

    Full Text Available ABSTRACT Natural latex from Hevea brasiliensis (Wild. ex A.Juss Müll.Arg., Euphorbiaceae, showed angiogenic action and Casearia sylvestris Sw., Salicaceae, leaf derivatives presented anti-inflammatory and wound healing activities. Therefore, an association of these effects was interesting for wound healing applications. The aims of this study were the development of membranes of natural latex incorporated with C. sylvestris leaf derivatives (ethanolic extract, diterpene concentrated fraction and casearin J, their chemical and physical characterization, and the evaluation of in vitro skin permeation and retention of C. sylvestris bioactive secondary metabolites (diterpenes and phenolic compounds. The membranes were developed mixing hydroethanolic solutions of C. sylvestris derivatives with latex and drying them in a desiccator. They were characterized by infrared spectroscopy, scanning electron microscopy, water vapor permeability and mechanical resistance assays, demonstrating that all membranes were permeable, resistant and homogeneous in surfaces. The permeation and retention assays demonstrated dermal penetration of phenolic compounds for ethanolic extract membrane and of casearin-like clerodane diterpenes for all membranes, indicating that these membranes have great potential for therapeutical application as a topical system for C. sylvestris components releasing.

  3. Content of Asthmagen Natural Rubber Latex Allergens in Commercial Disposable Gloves.

    Science.gov (United States)

    Bittner, C; Garrido, M V; Krach, L H; Harth, V

    The use of natural rubber latex (NRL) gloves in many occupations may lead to latex sensitization, allergic asthma, and skin reactions. Due to their good properties and environmental safety NRL gloves are still being used in the healthcare setting, but also in the food industry, by hairdressers, cleaners, etc. The aim of our study was to assess the protein and NRL allergen content in commercial gloves by different methods, including a new assay. Twenty commercially available NRL gloves were analyzed. Protein extraction was performed according to the international standard ASTM D-5712. Total protein content was measured with a modified Lowry method, NRL content with the CAP Inhibition Assay, the Beezhold ELISA Inhibition Assay, and an innovative ELISA with IgY-antibodies extracted from eggs of NRL-immunized hens (IgY Inhibition Assay). We found a high protein content in a range of 215.0-1304.7 μg/g in 8 out of the 20 NRL gloves. Seven of the 20 gloves were powdered, four of them with a high protein content. In gloves with high protein content, the immunological tests detected congruently high levels of NRL allergen. We conclude that a high percentage of commercially available NRL gloves still represent a risk for NRL allergy, including asthma. The modified Lowry Method allows to infer on the latex allergen content.

  4. Physical-biopolymer characterization of polyhydroxybutyrate-co-hydroxyvalerate (PHBV) blended with natural rubber latex

    Energy Technology Data Exchange (ETDEWEB)

    Kuntanoo, K., E-mail: thip-kk@hotmail.com [Graduate School of Khon Kaen University, Khon Kaen, 40002 Thailand (Thailand); Promkotra, S., E-mail: sarunya@kku.ac.th [Department of Geotechnology, Faculty of Technology, Khon Kaen University, Khon Kaen 40002 Thailand (Thailand); Kaewkannetra, P., E-mail: paknar@kku.ac.th [Department of Biotechnology, Faculty of Technology, Khon Kaen University, Khon Kaen 40002 Thailand (Thailand)

    2015-03-30

    A biopolymer of polyhydroxybutyrate-co-hydroxyvalerate (PHBV) is blended with bio-based materials, natural rubber latex, to improve their microstructures. The various ratios between PHBV and natural rubber latex are examined to develop their mechanical properties. In general, physical properties of PHBV are hard, brittle and low flexible while natural rubber (NR) is presented itself as high elastic materials. Concentrations of the PHBV solution are constituted at 1%, 2% and 3% (w/v). The mixtures of their PHBV solutions to natural rubber latex are produced the blended films in three different ratios of 4:6, 5:5 and 6:4, respectively. They are characterized by appearance analyses which are the scanning electron microscope (SEM), universal testing machine (UTM) and differential scanning calorimetry (DSC). The SEM photomicrographs of the blended films and the controlled PHBV can provide the void distribution in the range of 12-14% and 19-21%, respectively. For mechanical properties of the blended films, the various elastic moduli of 1%, 2% and 3% (w/v) PHBV are the average of 773, 956 and 1,007 kPa, respectively. The tensile strengths of the blends increase with the increased concentrations of PHBV, similarly trend to the elastic modulus. The crystallization and melting behavior of unmixed PHBV and the blends are determined by DSC. Melting transition temperatures (T{sub m}) of the unmixed PHBV are stated two melting peak at 154°C and 173°C. Besides, the melting peaks of the blends alter in the range of 152-156°C and 168-171°C, respectively. According to morphology of the blends, the void distribution decreases twice compared to the unmixed PHBV. The results of mechanical properties and thermal analysis indicate that the blended PHBV can be developed their properties by more resilient and wide range of temperature than usual.

  5. Fixation of tibial plateau fractures with synthetic bone graft versus natural bone graft: a comparison study.

    LENUS (Irish Health Repository)

    Ong, J C Y

    2012-06-01

    The goal of this study was to determine differences in fracture stability and functional outcome between synthetic bone graft and natural bone graft with internal fixation of tibia plateau metaphyseal defects.

  6. ENHANCEMENT OF RESISTANCE TO OXIDATIVE DEGRADATION OF NATURAL RUBBER THROUGH LATEX DEGRADATION

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    A fully characterised natural rubber latex was subjected to mechanical degradation by stirring at intervals. The resistance to oxidative degradation of the different samples were studied by measuring the Plasticity retention indices (PRI).The results show that there is an enhancement of the PRI from 57% for the undegraded rubber to 79% for the one-hour degraded sample. Further degradation resulted in decrease of PRI as time of degradation increased. Therefore, the one-hour degraded sample is a special rubber with high oxidation resistance which is of great importance in engineering.

  7. The influence of radiolytic sensitizers in natural rubber latex vulcanization induced by ionizing radiation

    International Nuclear Information System (INIS)

    Guedes, S.M.L.; Souza, A. de

    1991-01-01

    This work made on radiation vulcanization of natural rubber latex process by gamma rays from 60 Co source and electron beam of 1.5 MeV, 25 m A by Dynamitron, instead of classic process using sulfur. The experiment was carried out to study the influence of sensitizers (C Cl 4 and n-butyl acrylate) and was reported the vulcanization dose for each sensitizers, related to maximum tensile strength. The results show the possibility to introduce the volatile sensitizer (n-butyl acrylate) instead of C Cl 4 (toxic) in industry applications. (author)

  8. Surgical gloves fabrication using natural rubber latex vulcanized with gamma radiation

    International Nuclear Information System (INIS)

    Collantes, Hugo David Chirinos.

    1995-01-01

    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 2 ] + 0.019 t. (author). 49 refs., 13 figs., 31 tabs

  9. Effect of Antioxidants on Radiation Vulcanization Natural Rubber Latex (RVNRL) Film

    International Nuclear Information System (INIS)

    Syuhada Ramli; Sofian Ibrahim; Muhammad Saiful Omar

    2015-01-01

    This paper presents the results on the effects of different antioxidants used in Radiation Vulcanization Natural Rubber Latex (RVNRL)) films between 0 to 10 weeks monitoring. Antioxidants used for the RVNRL formulation were Aquanox LP, Irganox and Wingstay L. Color difference evaluation by using Chroma Meter CR-400 found that RVNRL film with Irganox was the most stained yellowish after 8 weeks monitoring. Tensile strength for RVNRL with Aquanox found achieved the optimum strength between 25.4 to 27.13 mPa. The scanner electron microscopic (SEM) indicated more Aquanox molecules to penetrate and interact with the rubber molecule, thus becoming more effective inhibitor against its oxidative ageing. (author)

  10. Modification of Iraqi Asphalt 40/50 Properties Using Saw Dust (SD and Natural Rubber Latex

    Directory of Open Access Journals (Sweden)

    Rusul l M. Darwesh

    2018-04-01

    Full Text Available The aim of this research is to enhance the fundamental properties for asphalt binder as those spec-ifications relate to performance of asphalt mixtures. In this paper studied the effect of add (2, 4 % SD in different sizes and (3, 5 and 7% Natural rubber latex to the straight asphalt 40/50 produced from Al-Dura refinery at 160C, it was added each additive separately and then added together to asphalt in same temperature, then tested physically and mechanically according to the American Society for Testing and Materials (ASTM, the result showed largely improvement.

  11. Green synthesis of colloidal silver nanoparticles using natural rubber latex extracted from Hevea brasiliensis.

    Science.gov (United States)

    Guidelli, Eder José; Ramos, Ana Paula; Zaniquelli, Maria Elisabete D; Baffa, Oswaldo

    2011-11-01

    Colloidal silver nanoparticles were synthesized by an easy green method using thermal treatment of aqueous solutions of silver nitrate and natural rubber latex (NRL) extracted from Hevea brasiliensis. The UV-Vis spectra detected the characteristic surface plasmonic absorption band around 435 nm. Both NRL and AgNO(3) contents in the reaction medium have influence in the Ag nanoparticles formation. Lower AgNO(3) concentration led to decreased particle size. The silver nanoparticles presented diameters ranging from 2 nm to 100 nm and had spherical shape. The selected area electron diffraction (SAED) patterns indicated that the silver nanoparticles have face centered cubic (fcc) crystalline structure. FTIR spectra suggest that reduction of the silver ions are facilitated by their interaction with the amine groups from ammonia, which is used for conservation of the NRL, whereas the stability of the particles results from cis-isoprene binding onto the surface of nanoparticles. Therefore natural rubber latex extracted from H. brasiliensis can be employed in the preparation of stable aqueous dispersions of silver nanoparticles acting as a dispersing and/or capping agent. Moreover, this work provides a new method for the synthesis of silver nanoparticles that is simple, easy to perform, pollutant free and inexpensive. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Properties and Characterization of Kenaf-Filled Natural Rubber Latex Foam

    Directory of Open Access Journals (Sweden)

    Ahmad Fikri Abdul Karim

    2015-12-01

    Full Text Available Kenaf powder was incorporated with natural rubber latex (NRL compound and foamed to make natural rubber latex foam (NRLF by using a well known technique called the Dunlop method. Different loadings of kenaf powder were added to NRL compound and was foamed to make NRLF. The mechanical properties, density, compression, thermal, and micro-structural characterization of control NRLF and kenaf incorporated NRLF were studied. Increasing content of kenaf reduced the tensile strength, elongation at break, and compressive strength of a NRLF. Modulus at 100% elongation and density of the NRLF increased with an increase in filler loading. Higher kenaf loading indicated higher elasticity of kenaf-filled NRLF, but the recovery percentage of kenaf-filled NRLF decreased with increasing kenaf loading. From thermogravimetric analysis (TGA result, an increase in the amount of kenaf loading from 1 to 7 phr increased the thermal stability of kenaf-filled NRLF. Morphological and micro-structural characterization performed by using scanning electron microscopy (SEM showed that kenaf powder filled up the micro-sized pores in the open cell structure of kenaf-filled NRLF.

  13. Isolation of natural inhibitors of papain obtained from Carica papaya latex

    Directory of Open Access Journals (Sweden)

    Rubens Monti

    2004-09-01

    Full Text Available Studies were carried out to natural papain inhibitor from papaya latex. Fresh latex from green fruits of Carica papaya was collected and immediately transported in ice bath to the lab, from which three fractions with inhibitor effect of esterase papain activity were isolated by latex dialysis, Sephadex G-25 gel filtration and ionic exchange chromatography in SP-Sephadex C-25. The isolated fractions, identified as inhibitors I and II, showed a negative reaction with ninhydrin; however, the fraction identified as P-III showed positive reaction with ninhydrin. Kinetics data showed non-competitive inhibition (inhibitor I and uncompetitive (inhibitors II and P-III.Este trabalho apresenta novos dados sobre inibidores naturais de papaína. O látex fresco de frutos verdes de Carica papaya foi coletado pela manhã em plantações da região de Araraquara, SP, Brasil e imediatamente transportado ao laboratório em banho de gelo. Três frações com efeito inibitório da atividade esterásica da papaína foram isoladas a partir do látex fresco, através de diálise, filtração em Sephadex G-25 e cromatografia em SP-Sephadex C-25. As frações isoladas identificadas como inibidores I e II, mostraram reação negativa à ninidrina; entretanto, a fração identificada como P-III mostrou reação positiva. Dados cinéticos revelaram inibição não-competitiva (inibidor I e incompetitiva (inibidores II e P-III.

  14. Styrene grafted natural rubber reinforced by in situ silica generated via sol–gel technique

    Energy Technology Data Exchange (ETDEWEB)

    Sittiphan, Torpong [Program of Petrochemistry and Polymer Sciences, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Prasassarakich, Pattarapan [Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Poompradub, Sirilux, E-mail: sirilux.p@chula.ac.th [Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand)

    2014-02-15

    Highlights: • Sol–gel reaction by NR latex was the absence of use of organic solvent and base catalyst. • Well dispersed in situ formed silica particles in the rubber matrix were obtained. • In situ silica was better to improve mechanical properties of rubber vulcanizates. -- Abstract: The filling of styrene graft natural rubber (ST-GNR) with in situ formed silica was performed using the sol–gel reaction via the latex solution method. The mechanical properties of ST-GNR/NR vulcanizate were improved when using the in situ formed silica to levels higher than those obtained with the commercial ex situ formed silica filled ST-GNR/NR vulcanizates at a comparable silica content of 12 parts by weight per hundred parts of rubber. Transmission electron microscopy analysis revealed that the in situ silica particles were small (∼40 nm diameter) and well dispersed, while the commercial silica particles were larger (∼60 nm diameter) and markedly agglomerated in the rubbery matrix. The mechanical properties of the composites prepared via both the solid rubber and latex solution methods were comparable.

  15. Development of an efficient process for radiation vulcanization of natural rubber latex using hydroperoxide with sensitizer

    International Nuclear Information System (INIS)

    Siri-upathum, C.; Sonsuk, M.

    1996-01-01

    An attempt was made to reduce irradiation dose for radiation vulcanization of natural rubber latex. A promising method was to partially crosslink the latex by radiation vulcanization using n-butyl acrylate (n-BA) as sensitizer and t-butyl hydroperoxide (BHPO) as a co-sensitizer followed by redox vulcanization using residual BHPO as an oxidant and either fructose or tetra ethylene penta mine as reducing agents. It was found that the irradiation dose was reduced to 4 kGy with 5 phr n-BA as sensitizer and 0.1 phr BHPO as co-sensitizer. Successive crosslinking to full vulcanization was done by redox vulcanization using either 4 phr fructose at 60 degree C for 3 hours of 0.4 phr tetra-ethylene penta mine at room temperature for 1 hour. The rubber films obtained had tensile strength of about 25 MPa, modulus 300% of 0.9 MPa and crosslink density of about 1.5 x 10 19 crosslink/cm 3 . It was noted that the rubber film from the co-vulcanization was the average value of the values obtained by radiation vulcanization and redox vulcanization

  16. Natural rubber latex used as drug delivery system in guided bone regeneration (GBR

    Directory of Open Access Journals (Sweden)

    Rondinelli Donizetti Herculano

    2009-06-01

    Full Text Available In this work, we propose natural rubber latex (NRL membranes as a protein delivery system. For this purpose Bovine Serum Albumin (BSA was incorporated into the latex solution for in vitro protein delivery experiments. Different polymerization temperatures were used, from -10 to 27 °C, in order to control the membrane morphology. These membranes were characterized by Scanning Electron Microscopy (SEM, Atomic Force Microscopy (AFM, as well as the Lowry Method to measure the BSA release. SEM and AFM microscopy analysis showed that the number, size and distribution of pores in NRL membranes can be varied, as well as its overall morphology. We have found that the morphology of the membrane is the predominant factor for higher protein release, compared with pore size and number of pores. Results demonstrated that the best drug-delivery system was the membrane polymerized at RT (27 °C, which does release 66% of its BSA content for up to 18 days. Our results indicate that NRLb could be used in the future as an active membrane that could accelerate bone healing in GBR.

  17. A system for treatment of diabetic foot ulcers using led irradiation and natural latex

    Directory of Open Access Journals (Sweden)

    Gustavo Adolfo Marcelino de Almeida Nunes

    Full Text Available Abstract Introduction: We developed and tested a new system for inducing the healing of diabetic foot ulcers. The system relies on the regenerative properties of its two components: an insole with a sheet of natural latex and a device that contains a matrix of light emitting diodes with wavelength of 635 nm. Methods The electronic and latex based devices were developed, and a four weeks test was performed in one control group (CG of five ulcers and one experimental group (EG of eight ulcers. The CG was treated with a standard approach, based on a silver-releasing foam dressing, and the EG was treated with the system under test. For each ulcer, an index for quantifying the percentage ulcer recovery, named CRU(%, has been calculated; a CRU(% = 0% means no healing, and a CRU(% = 100% means total healing. Results There were statistically significant increases of CRU(% of 51.8% (p = 0.022, for the CG, and of 78.4% (p < 0.001, for the EG. The increase in the EG was higher than the increase in the CG, and the difference was statistically significant (p < 0.001. The results showed that the proposed method had, for these particular sets of ulcers, faster healing rates, than for the standard method. Conclusion The results hint that the proposed method seems promising as a future treatment method. However, the technique must undergo further testing before it can be considered for extensive clinical applications.

  18. Diclofenac Potassium Transdermal Patches Using Natural Rubber Latex Biomembranes as Carrier

    Directory of Open Access Journals (Sweden)

    Natan Roberto de Barros

    2015-01-01

    Full Text Available The aim of this study was to design a compound transdermal patch containing diclofenac potassium (Dic-K using natural rubber latex (NRL biomembrane. The NRL from Hevea brasiliensis is easily manipulated and low cost and presents high mechanical resistance. It is a biocompatible material which can stimulate natural angiogenesis and is capable of adhering cells on its surface. Recent researches have used the NRL for Transdermal Drug Delivery Systems (TDDSs. Dic-K is used for the treatment of rheumatoid arthritis and osteoarthritis and pain relief for postoperative and posttraumatic cases, as well as inflammation and edema. Results showed that the biomembrane can release Dic-K for up to 216 hours. The kinetics of the Dic-K release could be fitted with double exponential function. X-ray diffraction and Fourier Transform Infrared (FTIR spectroscopy show some interaction by hydrogen bound. The results indicated the potential of the compound patch.

  19. Preparation of Low Allergenic Protein Concentrated Natural Rubber Latex Using Suitable Low Molecular Weight Cellulose Derivatives Induced by Gamma Irradiation

    International Nuclear Information System (INIS)

    Siri-Upathum, Chyagrit; Boonyawat, Jariya

    2007-08-01

    Full text: Low molecular weight carboxy methyl cellulose (CMC), hydroxyl ethyl cellulose (HEC), hydroxyl propyl cellulose (HPC) and methyl cellulose (MC) prepared by radiation-induced degradation were added into diluted natural concentrated latex prior to centrifuge for a purpose of reducing allergenic rubber protein in the latex. Optimum molecular weight (Mv) of CMC and HEC for such a purpose was found to be 17-18 kDa which decreased allergenic rubber protein (14-94 kDa) to an undetectable amount as determined by SDS PAGE method

  20. Antifungal activity of fluconazole-loaded natural rubber latex against Candida albicans.

    Science.gov (United States)

    Yonashiro Marcelino, Mônica; Azevedo Borges, Felipe; Martins Costa, Ana Flávia; de Lacorte Singulani, Junya; Ribeiro, Nathan Vinícius; Barcelos Costa-Orlandi, Caroline; Garms, Bruna Cambraia; Soares Mendes-Giannini, Maria José; Herculano, Rondinelli Donizetti; Fusco-Almeida, Ana Marisa

    2018-03-01

    This work aimed to produce a membrane based on fluconazole-loaded natural rubber latex (NRL), and study their interaction, drug release and antifungal susceptibility against Candida albicans. Fluconazole-loaded NRL membrane was obtained by casting method. The Fourier Transform Infrared Spectroscopy showed no modifications either in NRL or fluconazole after the incorporation. Mechanical test presented low Young's modulus and high strain, indicating the membranes have sufficient elasticity for biomedical application. The bio-membrane was able to release the drug and inhibit the growth of C. albicans as demonstrated by disk diffusion and macrodilution assays. The biomembrane was able to release fluconazole and inhibit the growth of C. albicans, representing a promising biomaterial for skin application.

  1. Formation of protein complex with the aid of polyethylene glycol for deproteinized natural rubber latex

    Science.gov (United States)

    Wei, Lim Keuw; Ing, Wong Kwee; Badri, Khairiah Haji; Ban, Wong Chong

    2013-11-01

    The effect of polyethylene glycol (PEG) as a deproteinizing agent in commercial natural rubber latex (NRL) onto the physicochemical properties of the NRL was investigated. Three types of PEG were used namely PEG200, PEG4000 and PEG20000 (molecular weight of 200, 4000 and 20000 g/mol respectively). The optimum amount of PEG in NRL was determined from viscosity changes, protein content and Fourier Transform Infrared spectroscopy. Level of protein reduction was affected by molecular weight of PEG. The addition of PEG in NRL reduced the protein content of NRL (3.30 %) to the lowest (2.01 %) at 0.40 phr of PEG200 due to more attractive hydrophobic interactions between short chains PEG compared to PEG4000 (2.24%) and PEG20000 (2.15%). This was verified through FTIR spectroscopy analysis by observing the primary and secondary amide peak where PEG4000 has lesser absorption at the region compared to with PEG20000.

  2. Characteristic of natural rubber latex-methyl metha-crylate copolymer in mineral lubricant base oil

    International Nuclear Information System (INIS)

    Meri Suhartini; Rahmawati

    2010-01-01

    Natural rubber latex-methyl methacrylate copolymer was diluted in xylene, then diluted in four types of lubricant base oil with concentrations of 0.25%, 1%, 5%, and 10%. The mixed solutions were analyzed to obtain kinematics viscosity, viscosity index, density, ash content, metal content, flash point, shear stability and total alkali number. The viscosity index of sample, increased by adding the copolymer solution. The results showed that lubricant base oil of High Viscosity index (HVI) 60 and mixed HVI 60: HVI 650 gave optimum viscosity index. The higher concentration of polymer added into base lubricant oil, the higher viscosity index obtained. The shear stability test showed that the kinematics viscosity of sample decreased 6.5% after 60 minutes of treatment test. (author)

  3. Toxicological evaluation of natural rubber latex film vulcanized with ionizing radiation

    International Nuclear Information System (INIS)

    Campos, Vania E.; Higa, Olga Z.; Guedes, Selma M.L.; Hanada, Seico

    1999-01-01

    The industrial vulcanization of natural rubber latex (NRL) is made worldwide by conventional process using sulphur, but it can be made by an alternative process using ionizing radiation. The main advantages of this process are related to absence of toxic effect promoted by chemical substances added to the NRL on the conventional process. In this research was tested the toxicological properties of the films vulcanized by the alternative process in relation to that vulcanized by the conventional process. The toxicity was evaluated by in vitro cytotoxicity assay and in vivo systemic toxicity assay. The results showed that vulcanized films by gamma ray are less cytotoxic. The systemic toxicity assay showed that only the vulcanized film using sulphur induced allaying and motor in coordination on the animals for a short period of time. these results evidence the less cytotoxic properties of vulcanized films by gamma ray in relation to that vulcanized by conventional process using sulphur. (author)

  4. Properties of natural rubber/attapulgite composites prepared by latex compounding method: Effect of filler loading

    International Nuclear Information System (INIS)

    Muttalib, Siti Nadzirah Abdul; Othman, Nadras; Ismail, Hanafi

    2015-01-01

    This paper reports on the effect of filler loading on properties of natural rubber (NR)/attapulgite (ATP) composites. The NR/ATP composites were prepared by latex compounding method. It is called as masterbatch. The masterbatch was subsequently added to the NR through melt mixing process. The vulcanized NR/ATP composites were subjected to mechanical, swelling and morphological tests. All the results were compared with NR/ATP composites prepared by conventional system. The composites from masterbatch method showed better results compared to composites prepared by conventional method. They have higher tensile properties, elongation at break and tear strength. The images captured through scanning electron microscopy test revealed the improvement of tensile strength in masterbatch NR/ATP composites. It can be seen clearly that masterbatch NR/ATP have better filler dispersion compared to conventional method NR/ATP composites

  5. Properties of natural rubber/attapulgite composites prepared by latex compounding method: Effect of filler loading

    Energy Technology Data Exchange (ETDEWEB)

    Muttalib, Siti Nadzirah Abdul, E-mail: sitinadzirah.amn@gmail.com; Othman, Nadras, E-mail: srnadras@usm.my; Ismail, Hanafi, E-mail: ihanafi@usm.my [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, Seri Ampangan, 14300 Nibong Tebal, Pulau Pinang (Malaysia)

    2015-07-22

    This paper reports on the effect of filler loading on properties of natural rubber (NR)/attapulgite (ATP) composites. The NR/ATP composites were prepared by latex compounding method. It is called as masterbatch. The masterbatch was subsequently added to the NR through melt mixing process. The vulcanized NR/ATP composites were subjected to mechanical, swelling and morphological tests. All the results were compared with NR/ATP composites prepared by conventional system. The composites from masterbatch method showed better results compared to composites prepared by conventional method. They have higher tensile properties, elongation at break and tear strength. The images captured through scanning electron microscopy test revealed the improvement of tensile strength in masterbatch NR/ATP composites. It can be seen clearly that masterbatch NR/ATP have better filler dispersion compared to conventional method NR/ATP composites.

  6. Study of the effect of ionizing radiation on the structure of natural rubber latex by positron annihilation technique

    International Nuclear Information System (INIS)

    Lopez Saldana, I.R.

    1993-01-01

    At the present research, were studied the changes in natural rubber latex structure, due to electron beam by a 3 MeV, 25 m A Dynamitron electron accelerator. The natural rubber latex was irradiated at 30, 40 and 50 kGy/s dose rate, over a total dose range from 150 to 250 kGy, for each dose rate used. From natural rubber latex irradiated films were prepared by casting with 0.7 mm. thickness. In the main part, the study was made by positron annihilation lifetime (PAL), this technique is unique in the determination of free-volume properties due to the fact that positronium atom (Ps) is found to be preferentially localized in the free-volume region of polymeric materials. The positron lifetime measurements were performing using a gamma-gamma coincidence system. These results were analyzed by PATFIT-88 program computer into three components, the long-lived component for orthopositronium (o-Ps) with parameters lifetime (τ 3 ) and formation intensity (I 3 ), were plotted and analyzed for each dose rate and total dose used. Besides with τ 3 were calculated the mean free-volume size based on the spherical model for the free-volume bubble, found that the free-volume decrease slightly with the total dose due to the crosslinking of natural rubber latex. Besides was studied the effect of dose rate on tensile strength, the tensile strength is increased with the total dose although there was not a clear effect due to the dose rate. Also the films were subjected to aging in order to determined the thermal stability of natural rubber latex irradiated, the results show that the films have good stability. Besides was used the infrared spectroscopy to determine the changes due to the crosslinking by variations in the characteristically absorption bands for cis 1,4-polyisoprene. (Author)

  7. Ten years incidence of natural rubber latex sensitization and symptoms in a prospective cohort of health care workers using non-powdered latex gloves 2000-2009.

    Science.gov (United States)

    Larese Filon, Francesca; Bochdanovits, Letizia; Capuzzo, Chiara; Cerchi, Roberto; Rui, Francesca

    2014-07-01

    To assess the incidence of sensitization and gloves-related symptoms in 10-year follow-up in a group of health care workers (9,660 person-years) using non-powdered latex gloves from 2000 to 2009 and to examine related factors. We studied 2,053 health care workers in Trieste Hospitals by means of skin prick test for latex extract, patch tests and medical examinations. We report the incidence of latex sensitization among workers using non-powdered latex gloves. The incidence of latex sensitization, rhinitis, asthma, urticaria, irritant and allergic contact dermatitis were 1.0; 0.12; 0.21; 0.72; 2.39 and 2.50 cases per 1,000 person-years, respectively. Respiratory symptoms and urticaria were positively related with latex sensitization (OR = 8.0; 95 % CL 1.27-48.6), with common allergic respiratory symptoms (OR = 4.19; 95 % CL 1.04-16.8) and with familial atopy (OR = 4.47; 95 % CL 1.1-17.9). The incidence of latex sensitization and latex-related symptoms were very low but subjects with allergic symptoms related to common allergens are at higher risk. The use of non-latex gloves is suggested for them.

  8. Nature or Artifice? Grafting in Early Modern Surgery and Agronomy.

    Science.gov (United States)

    Savoia, Paolo

    2017-01-01

    In 1597, Gaspare Tagliacozzi published a famous two-volume book on “plastic surgery.” The reconstructive technique he described was based on grafting skin taken from the arm onto the mutilated parts of the patient's damaged face – especially noses. This paper focuses on techniques of grafting, the “culture of grafting,” and the relationships between surgery and plant sciences in the sixteenth century. By describing the fascination with grafting in surgery, natural history, gardening, and agronomy the paper argues that grafting techniques were subject to delicate issues: to what extent it was morally acceptable to deceive the eye with artificial entities? and what was the status of the product of a surgical procedure that challenged the traditional natural/artificial distinction? Finally, this paper shows how in the seventeenth century grafting survived the crisis of Galenism by discussing the role it played in teratology and in controversies on the uses the new mechanistic anatomy.

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

    International Nuclear Information System (INIS)

    Zhu Nankang; Wang Chunlei; Makuuchi, K.; Yoshii, F.

    1996-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-07-01

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

  11. Trial production of low protein irradiated natural rubber latex by low energy electron beam in pilot scale

    International Nuclear Information System (INIS)

    Utama, Marga; Yoshii, F.; Kume, T.

    2006-01-01

    Three importance factors for producing low protein by low energy electron beam (250 keV/10 mA) irradiation in pilot scale (20 liters per bath) with 1,9-nonediol diacrylate (NDA) namely: maturation time of natural rubber latex before irradiation, treatment of irradiated natural rubber latex (INRL) before and after centrifugation, and standard irradiation method has been carried out. The results showed that the optimum irradiation time for producing INRL with 5 phr (part hundred ratio of rubber) of NDA as sensitize agent, and with the rotation speed of agitation 210 rpm (rotation per minutes) was between 20-30 minutes. By using this condition tensile strength of the INRL film was 26 MPa. The maturation of natural rubber latex before irradiation is the key for driving the quality of INRL. Water extractable protein content of INRL after leaching in 1% ammonia solution for 30 minutes at room temperature was around 47 μ/g, and after adding with 1 phr of PVA (poly vinyl alcohol) or 0.1 phr CMC (carboxy methyl cellulose) the water extractable protein content decrease less than 6 μ/g. (author)

  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. Outcomes of a natural rubber latex control program in an Ontario teaching hospital.

    Science.gov (United States)

    Tarlo, S M; Easty, A; Eubanks, K; Parsons, C R; Min, F; Juvet, S; Liss, G M

    2001-10-01

    Allergy to natural rubber latex (NRL) has been frequently reported in health care workers. However, there is little published evidence of the outcome of hospital intervention programs to reduce exposure and detect cases of sensitization early. This study assesses the effects of intervention to reduce NRL allergy in an Ontario teaching hospital with approximately 8000 employees. A retrospective review assessed annual numbers of employees visiting the occupational health clinic, allergy clinic, or both for manifestations of NRL allergy compared with the timing of introduction of intervention strategies, such as worker education, voluntary medical surveillance, and hospital conversion to low-protein, powder-free NRL gloves. The number of workers identified with NRL allergy rose annually, from 1 in 1988 to 6 in 1993. When worker education and voluntary medical surveillance were introduced in 1994, a further 25 workers were identified. Nonsterile gloves were changed to low-protein, powder-free NRL gloves in 1995: Diagnoses fell to 8 workers that year, and 2 of the 3 nurses who had been off work because of asthma-anaphylaxis were able to return to work with personal avoidance of NRL products. With a change to lower protein, powder-free NRL sterile gloves in 1997, allergy diagnoses fell to 3, and only 1 new case was identified subsequently up to May 1999. No increased glove costs were incurred as a result of consolidated glove purchases. This program to reduce NRL allergy in employees was effectively achieved without additional glove costs while reducing expenses from time off work and workers' compensation claims.

  14. Evaluation of sodium diclofenac release using natural rubber latex as carrier

    International Nuclear Information System (INIS)

    Aielo, Patricia B.; Borges, Felipe A.; Romeira, Karoline M.; Herculano, Rondinelli D.; Miranda, Matheus Carlos Romeiro; Arruda, Larisa B. de; Lisboa Filho, Paulo Noronha; Drago, Bruno de C.

    2014-01-01

    Sodium Diclofenac is a non-steroidal anti-inflammatory drug (NSAID) taken to reduce inflammation and, as an analgesic, reduce pain. Although this drug is widely used in the general population, properties such as the short half-time and some side effects restrict its clinical use. The most common side effects are: gastric irritation, gastritis, peptic ulcer and bleeding. Studies involving biomaterials as carrier for drug release have been proving their efficiency in overcoming those problems and better controlling the release rate and targeting of the drug. Natural rubber latex (NRL) has been proven excellent for its biocompatibility and ability to stimulate angiogenesis, cellular adhesion and the formation of extracellular matrix, promoting the replacement and regeneration of tissue. In this work, a NRL membrane is used to deliver sodium diclofenac. Sodium diclofenac (NaDic) was found to be adsorbed on the NRL membrane, with little or no incorporation into the membrane bulk, according to energy dispersive Scanning Electron Microscopy with X-Ray microanalysis (SEM-EDS) spectroscopy. In addition, FT-IR shows that there is no molecular-level interaction between drug and NRL. Already, the X-Ray Diffraction (XRD) of NaDic-NRL shows a broader one spectrum than the sharper halo (amorphous characteristic XRD spectrum) of pure NRL. More importantly, the release time of diclofenac in a NRL membrane in vitro was increased from the typical 2-3 h for oral tablets to ca. 74 h. The kinetics of the drug release could be fitted with a double exponential function, with two characteristic times of 0.899 and 32.102 h. In this study, we demonstrated that the interesting properties provided by NRL membranes combined with a controlled release of drug is relevant for biomedical applications.(author)

  15. Evaluation of sodium diclofenac release using natural rubber latex as carrier

    Energy Technology Data Exchange (ETDEWEB)

    Aielo, Patricia B.; Borges, Felipe A.; Romeira, Karoline M.; Herculano, Rondinelli D., E-mail: rond@assis.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Assis, SP (Brazil). Fac. de Ciencias e Letras. Dept. de Ciencias Biologicas; Miranda, Matheus Carlos Romeiro [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Araraquara, SP (Brazil). Inst. de Quimica; Arruda, Larisa B. de; Lisboa Filho, Paulo Noronha; Drago, Bruno de C. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Bauru, SP (Brazil). Fac. de Ciencias. Dept. de Fisica

    2014-08-15

    Sodium Diclofenac is a non-steroidal anti-inflammatory drug (NSAID) taken to reduce inflammation and, as an analgesic, reduce pain. Although this drug is widely used in the general population, properties such as the short half-time and some side effects restrict its clinical use. The most common side effects are: gastric irritation, gastritis, peptic ulcer and bleeding. Studies involving biomaterials as carrier for drug release have been proving their efficiency in overcoming those problems and better controlling the release rate and targeting of the drug. Natural rubber latex (NRL) has been proven excellent for its biocompatibility and ability to stimulate angiogenesis, cellular adhesion and the formation of extracellular matrix, promoting the replacement and regeneration of tissue. In this work, a NRL membrane is used to deliver sodium diclofenac. Sodium diclofenac (NaDic) was found to be adsorbed on the NRL membrane, with little or no incorporation into the membrane bulk, according to energy dispersive Scanning Electron Microscopy with X-Ray microanalysis (SEM-EDS) spectroscopy. In addition, FT-IR shows that there is no molecular-level interaction between drug and NRL. Already, the X-Ray Diffraction (XRD) of NaDic-NRL shows a broader one spectrum than the sharper halo (amorphous characteristic XRD spectrum) of pure NRL. More importantly, the release time of diclofenac in a NRL membrane in vitro was increased from the typical 2-3 h for oral tablets to ca. 74 h. The kinetics of the drug release could be fitted with a double exponential function, with two characteristic times of 0.899 and 32.102 h. In this study, we demonstrated that the interesting properties provided by NRL membranes combined with a controlled release of drug is relevant for biomedical applications.(author)

  16. Rapid synthesis of graft copolymers from natural cellulose fibers.

    Science.gov (United States)

    Thakur, Vijay Kumar; Thakur, Manju Kumari; Gupta, Raju Kumar

    2013-10-15

    Cellulose is the most abundant natural polysaccharide polymer, which is used as such or its derivatives in a number of advanced applications, such as in paper, packaging, biosorption, and biomedical. In present communication, in an effort to develop a proficient way to rapidly synthesize poly(methyl acrylate)-graft-cellulose (PMA-g-cellulose) copolymers, rapid graft copolymerization synthesis was carried out under microwave conditions using ferrous ammonium sulfate-potassium per sulfate (FAS-KPS) as redox initiator. Different reaction parameters such as microwave radiation power, ratio of monomer, solvent and initiator concentrations were optimized to get the highest percentage of grafting. Grafting percentage was found to increase with increase in microwave power up to 70%, and maximum 36.73% grafting was obtained after optimization of all parameters. Fourier transforms infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA/DTA/DTG) analysis were used to confirm the graft copolymerization of poly(methyl acrylate) (PMA) onto the mercerized cellulose. The grafted cellulosic polymers were subsequently subjected to the evaluation of different physico-chemical properties in order to access their application in everyday life, in a direction toward green environment. The grafted copolymers demonstrated increased chemical resistance, and higher thermal stability. Published by Elsevier Ltd.

  17. Efficiency of 1,9- Nonane-diol-diacrylate as a radiation vulcanization accelerator for natural rubber latex

    International Nuclear Information System (INIS)

    Haque, M.E.

    2003-09-01

    The efficiency of 1,9- Nonane-diol-diacrylate (NDDA) as a radiation vulcanization accelerator (RVA) for natural rubber latex (NRL) was investigated. Both gamma rays and electron beam (EB) were used for vulcanizing NRL with NDDA. The radiation dose of gamma rays, concentration of NDDA required to vulcanize the latex were optimized. 20 kGy radiation dose of gamma rays and 5 phr concentration of NDDA were found optimum to get maximum tensile and related properties. NRL was vulcanized under EB to find out the optimum condition of irradiation with this RVA. The defoamer concentrations, length of irradiation time under EB, concentration of RVA were optimizer by changing various parameters of the EB machine with a constant set of the others. 0.2 phr defoamer concentration, 30 minutes irradiation time and 5 phr concentration of NDDA were found optimum for irradiation of NRL under the EB machine. Effect of low current and optimum volume of latex charged in the reaction vessel suitable for vulcanization at a time were found out. (author)

  18. Analysis of sulfidic linkages formed in natural rubber latex medical gloves by using X-ray absorption near edge structure

    Science.gov (United States)

    Chankrachang, M.; Limphirat, W.; Yongyingsakthavorn, P.; Nontakaew, U.; Tohsan, A.

    2017-09-01

    A study of sulfidic linkages formed in natural rubber (NR) latex medical gloves by using X-ray Absorption Near Edge Structure (XANES) is presented in this paper. The NR latex compound was prepared by using prevulcanization method, that is, it was prevulcanized at room temperature for 24 hrs before utilization. After the 24 hrs of prevulcanization, the latex film samples were obtained by dipping process. The dipped films were subjected to vulcanize at 110°C for 5 to 25 min. It was observed that after the compound was prevulcanized for 24 hrs, polysulfidic linkages were mainly formed in the sample. It was however found that after curing at 110°C for 5-25 min, the polysulfidic linkages are tended to change into disulfide linkages. Especially, in the case of 25 minutes cured sample, disulfide linkages are found to be the main linkages. In term of tensile strength, it was observed that when cure time increased from 5 - 10 min, tensile strengths were also increased. But when the cure time of the film is 25 minutes, tensile strength was slightly dropped. The dropped of tensile strength when cure time is longer than 10 minutes can be ascribed to a degradation of polysulfidic and disulfidic linkages during curing. Therefore, by using XANES analysis, it was found to be very useful to understand the cure characteristic, thus it can be very helpful to optimize cure time and tensile properties of the product.

  19. Marketing techniques and cost calculations of radiation vulcanised natural rubber latex (RVNRL)

    International Nuclear Information System (INIS)

    Wan Manshol Wan Zin; Chai Chee Keong; Najib Mohammed Zakey; Hafizuddin Maseri

    2005-01-01

    This paper describes how RVNRL is promoted to the latex based industries locally and abroad. RVNRL promotion requires patience and very challenging. This is a fact since the product is new to the market. Cost is important in deciding its market and potential usage. The elements that contribute to the cost is described in this paper. (Author)

  20. Modification of natural leather by grafting emulsion copolymerization technique

    International Nuclear Information System (INIS)

    Badran, A.S.; Nasr, H.E.; El-Halawany, N.R.; Mohamed, W.S.

    2005-01-01

    Grafting emulsion copolymerization of methyl methacrylate (MMA) with butyl acrylate of different molar ratios onto natural leather with different molar ratios was carried out using developed redox initiation system of potassium persulphate (PPS) as an oxidizing agent and some sodium bisulphite adducts as reducing agent, as well as sodium dodecyl sulphate (SDS) was used as an anionic emulsifier. The grafted leather was characterized via FTIR, SEM and thermal gravimetric analysis. Moreover, the grafted leather was evaluated through water absorption, tensile strength, dyeing performance and hardness measurements. The obtained results revealed that the physical and mechanical properties of the modified leather were enhanced

  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. Hevea brasiliensis natural rubber latex film vulcanization by gamma radiation containing n-butyl acrylate: properties and morphology; Filme de latex de borracha natural de Hevea brasiliensis vulcanizado por radiacao gama contendo acrilato de n-butila: propriedades e morfologia

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Ana Paula Pinho; Barros, Glaucione Gomes de [Brasilia Univ., DF (Brazil). Dept. de Quimica; Guedes, Selma M.L. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

    1997-07-01

    Radiation vulcanization of natural rubber latex (RVNRL) in the presence of n-butyl acrylate (n-Ba) as sensitizer was carried out. The RVNRL films were investigated with respect to their thermal properties and morphology. The films presented two T{sub g} values obtained by DSC which were identified as due to linear and crosslinked domains. The thermal stability of the material was similar to that of linear material rubber. The morphology showed smooth regular surface characteristic of homogeneous phase domains. (author)

  3. Radio-vulcanization of natural rubber in the latex phase. Study of an experimental 1 tonne per hour production; Radio-vulcanisation du caoutchouc naturel en phase latex. Etude d'une production experimentale de 1 tonne par heure

    Energy Technology Data Exchange (ETDEWEB)

    Leveque, P; Puig, J R; Roudeix, H [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1968-07-01

    After briefly reviewing the main research carried out on the radio-vulcanization of latex and elastomers, a description is given of 4 types of cell which have been used successively with a view to industrial irradiation. They have made it possible to acquire the information necessary for resolving the main problem arising during irradiation - the formation of coagulum. The first two cell are designed for irradiation by a horizontal beam ('Dynamitron'), the two others use a vertical beam ('Circe'). The study of the properties of the rubber obtained shows it to compare favorably with 'Revultex'. In the appendix are given some characteristics of natural latex and information about its processing. (authors) [French] Apres un rappel des principales etudes sur la radio-vulcanisation du latex et des elastomeres, on decrit les quatre types de cellules successivement essayes en vue de l'irradiation industrielle. Ils ont permis d'acquerir les informations necessaires a la resolution du probleme principal pose par l'irradiation, la formation de coagulum au cours de celle,-ci. Les deux premiers sont concus pour l'irradiation par un faisceau horizontal ('Dynamitron'), les derniers par un faisceau vertical ('Circe'). L'etude des proprietes du caoutchouc obtenu montre qu'il se compare favorablement au 'Revultex'. Un apercu est donne en annexe des caracteristiques du latex naturel et de sa mise en oeuvre. (auteurs)

  4. 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

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

    International Nuclear Information System (INIS)

    Keizo Makuuchi; Fumio Yoshii; Miura, H.; Murakami, K.

    1996-01-01

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

  6. Quality and quantity of latex which can be produced from natural vegetation in Greece

    Energy Technology Data Exchange (ETDEWEB)

    Margaris, N.S.; Vokou, D.; Diamantopoulos, J.

    1985-01-01

    Euphorbiaceae is one of the major latex producing families very promising in terms of exploitation as energy sources. Research in the Greek areas proved that Euphorbia species are very numerous with high contribution in biomass terms in many of them. Provided are data concerning growth characteristics of E. dendroides and E. acanthothamnos to answer the question of the feasibility of harvesting. E. helioscopia is proved to be a very promising species with many ecotypes. Its occurrence and extremely increased growth in olive, almonds, and pear plantations makes it a very important species needing further research to evaluate the possibility of combined cultivation with the above mentioned trees. It is estimated the oil production that such plantations may yield.

  7. Studied on Virgin Coconut Oil (VCO) and Olive Oil (OO) as an Alternative for Stabilizer of Radiation Vulcanized Natural Rubber Latex (RVNRL) Preparation

    International Nuclear Information System (INIS)

    Syuhada Ramli; Sofian Ibrahim; Mohd Noorwadi Mat Lazim

    2016-01-01

    This paper presents the effects of virgin coconut oil (VCO) and olive oil (OO) as an alternative stabilizer in the radiation vulcanized natural rubber latex (RVNRL). Potassium laurite (KL) as a stabilizer considered as a control of RVNRL sample were compared to mixed ratio 1:1 KL: VCO and 1:1 KL: OO stabilizer formulation. Total solid content (TSC) and tensile strength (TS) results showed no significant different between the formulations. Mechanical stability time (MST) indicates higher stability of RVNRL with addition of VCO. The fatty acid composition in VCO indicate VCO was acting well as stabilizer for latex stabilizer formulation. (author)

  8. Combination of Tung oil and Natural Rubber Latex in PVA as Water Based Coatings for Paperboard Application

    Directory of Open Access Journals (Sweden)

    Jianprasert Apichaya

    2015-01-01

    Full Text Available This research is focused on the preparation of the PVA/TO/NRL coatings for paperboard by using poly(vinyl alcohol (PVA as substance and blending with Tung oil (TO and/or natural rubber latex (NRL in order to enhance water resistance and dynamic mechanical properties. The effects of TO: NRL ratios on the structures were investigated by water resistance property and dynamic mechanical thermal analysis (DMA. The results showed that the water resistance property was improved by crosslinking of TO and film forming of NRL. The PVA/TO/NRL coating containing both TO and NRL gave better thermal behavior than those with only TO or NRL. For paperboard application, the PVA/TO/NRL coatings were applied on the paperboard to study water affinity and absorption rate on the coated surface. The rate of contact angle change of water on coated paperboards decreased depending on the ratios of TO and NRL.

  9. Substituição parcial do pericárdio de cães por membrana de látex natural Partial replacement of dog pericardium with a natural latex membrane

    Directory of Open Access Journals (Sweden)

    Soraya Lopes SADER

    2000-12-01

    leucograma e ao ECG, apenas inversão da onda T, em todos os grupos. CONCLUSÃO: A membrana de látex natural mostrou-se adequada para a substituição parcial do pericárdio de cães, em observação de até 345 dias, propiciando a regeneração do pericárdio nativo.BACKGROUND: There are numerous advantages in closing the pericardial cavity after heart surgery and intrapericardial pneumonectomies. OBJECTIVE: To study the behavior of a natural latex membrane as a partial pericardium substitute. MATERIAL AND METHODS: Sixteen dogs divided into 3 groups were submitted to resection of an elliptical flap of the left anterolateral portion of the pericardium (7 x 5 cm: Group A (n=4 - the removed flap was immediately reimplanted; Group B (n=8 - the flap was replaced with a 0.3 mm thick natural latex membrane of equivalent area; Group C (n=4 - the latex flap was 0.7 mm thick. In all animals the flap was fixed with continuous 5-0 or 6-0 polypropylene sutures. In group C, 4 additional U-shaped stitches anchored with dacron pledgets were applied. All animals were submitted to ECG and to white cell counts during the preoperative period as well as to macro- and microscopic post mortem study. RESULTS: Group A - the self-graft was macro and microscopically intact, strongly adhering to the lung and loosely adhering to the epicardium; Group B - total suture dehiscence occurred in 1 animal and partial dehiscence in 2. The latex membrane did not adhere to the lung or to the epicardium. In 3 animals (37.5% there was full regeneration of the pericardium underlying the natural latex, microscopically identical to the native pericardium. Group C - the sutures were intact and total pericardium regeneration was observed in 3 animals (75%. In the remaining animals of Groups B and C, the epicardium underlying the latex was slightly thickened, permitting easy visualization of the coronary vessels. Some areas with dense lymphocytes and plasma cells infiltrates, fibroblast and vascular proliferation were

  10. Mechanical and Physical Studies on Different Doses of Radiation Pre vulcanized Natural Rubber Latex (RVNRL)

    International Nuclear Information System (INIS)

    Syuhada Ramli; Sofian Ibrahim; Muhammad Saiful Omar; Mohd Noorwadi Mat Lazim; Khairul Hisyam Mohamed Yusof; Najib Mohammmad Zakey; Hafizuddin Maseri

    2014-01-01

    RVNRL mixture of 12 kGy (RVNRL12) and 25 kGy (RVNRL25) at different blending ratios were prepared by stirring the mixture using a magnetic stirrer RVNRL at a speed of 1-3 rpm overnight to get the dough consistency. RVNRL12 with RVNRL25 attendance at a ratio of 90:10, 80:20, 70:30, 60:40 and 50:50 investigated. The study of physical and mechanical properties of 12/ 25 blends RVNRL performed on film samples prepared by immersion method coagulant. RVNRL25 result of the addition of the mixture RVNRL12 showed an increase in tensile strength mixture ratio of 90:10 RVNRL12 / RVNRL25 and tensile strength are declining at a ratio higher RVNRL25 content. Increase the tensile strength was found to increase due to the impact of lower doses of dough RVNRL12 and RVNRL25. This shows that blending RVNRL lower doses help improve the physical properties of latex due to exposure dose exceeding the dose required RVNRL. (author)

  11. A test trial irradiation of natural rubber latex on large scale for the production of examination gloves in a production scale

    International Nuclear Information System (INIS)

    Devendra, R.; Kulatunge, S.; Chandralal, H.N.K.K.; Kalyani, N.M.V.; Seneviratne, J.; Wellage, S.

    1996-01-01

    Radiation Vulcanization of natural rubber latex has been developed extensively through various research and development programme. During these investigations many data was collected and from these data it was proved that radiation vulcanized natural rubber latex (RVNRL) can be used as a new material for industry (RVNRL symposium 1989; Makuuchi IAEA report). This material has been extensively tested in making of dipped goods and extruded products. However these investigations were confined only to laboratory experiments and these experiments mainly reflected material properties of RVNRL and only a little was observed about its behavior in actual production scale operation. The present exercise was carried out mainly to study the behavior of the material in production scale by irradiating latex on a large scale and producing gloves in a production scale plant. It was found that RVNRL can be used in conventional glove plants without making major alteration to the plant. Quality of the gloves that were produced using RVNRL is acceptable. It was also found that the small deviation of vulcanization dose will affect the crosslinking density of films. This will drastically reduce the tensile strength of the film. Crosslinking density or pre-vulcanized relax modulus (PRM) at 100% is a reliable property to control the pre vulcanization of latex by radiation

  12. Plant Growth and Water Purification of Porous Vegetation Concrete Formed of Blast Furnace Slag, Natural Jute Fiber and Styrene Butadiene Latex

    Directory of Open Access Journals (Sweden)

    Hwang-Hee Kim

    2016-04-01

    Full Text Available The purpose of this study is to investigate porous vegetation concrete formed using the industrial by-products blast furnace slag powder and blast furnace slag aggregates. We investigated the void ratio, compressive strength, freeze–thaw resistance, plant growth and water purification properties using concretes containing these by-products, natural jute fiber and latex. The target performance was a compressive strength of ≥12 MPa, a void ratio of ≥25% and a residual compressive strength of ≥80% following 100 freeze–thaw cycles. Using these target performance metrics and test results for plant growth and water purification, an optimal mixing ratio was identified. The study characterized the physical and mechanical properties of the optimal mix, and found that the compressive strength decreased compared with the default mix, but that the void ratio and the freeze–thaw resistance increased. When latex was used, the compressive strength, void ratio and freeze–thaw resistance all improved, satisfying the target performance metrics. Vegetation growth tests showed that plant growth was more active when the blast furnace slag aggregate was used. Furthermore, the use of latex was also found to promote vegetation growth, which is attributed to the latex forming a film coating that suppresses leaching of toxic components from the cement. Water purification tests showed no so significant differences between different mixing ratios; however, a comparison of mixes with and without vegetation indicated improved water purification in terms of the total phosphorus content when vegetation had been allowed to grow.

  13. 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

  14. Epoxidação "in situ" aplicada ao látex de borracha natural "In situ" epoxidation of natural rubber latex

    Directory of Open Access Journals (Sweden)

    Cristiane K. Santin

    2012-01-01

    Full Text Available O comportamento da borracha natural na forma látex frente à reação de epoxidação foi avaliado visando estabelecer as melhores condições reacionais sem a ocorrência de reações laterais, que promovem a coagulação do látex e o desenvolvimento de um aglomerado de borracha. Grupos epóxidos foram gerados através da reação de epoxidação a partir da formação in situ do ácido perfórmico. As amostras foram caracterizadas qualitativamente por espectroscopia de infravermelho (FTIR e o grau de modificação determinado por ressonância magnética nuclear de hidrogênio (1H-RMN. Análises de calorimetria exploratória diferencial (DSC demonstraram que a mobilidade da cadeia polimérica foi influenciada pela presença de grupos epóxidos, com aumento linear na temperatura de transição vítrea (Tg. Os resultados indicaram que a epoxidação do látex de borracha natural, sem a ocorrência de reações laterais, é possível e dependente das condições reacionais.Natural rubber latex was submitted to epoxidation reaction to establish the best reaction conditions without the occurrence of side reactions, which promote coagulation of the latex and development of an agglomerate of rubber. Epoxy groups were produced by in situ epoxidation with formic acid and hydrogen peroxide. The samples were characterized qualitatively by Fourier Transform Infrared (FTIR analysis and the degree of modification determined by Hydrogen Nuclear Magnetic Resonance Spectroscopy (1H-NMR analysis. A linear increase in the glass transition temperature (Tg was observed. The results show that the epoxidation of natural rubber latex is possible and depends on the reaction conditions.

  15. Radiation induced grafting of monomers onto natural rubber : processes and applications

    International Nuclear Information System (INIS)

    Sunny Sebastian, M.

    2001-01-01

    Full text: Certain inherent mechanical properties of natural rubber (NR) can be modified by grafting vinyl monomers onto the polymer backbone. This paper described the gamma radiation induced graft copolymerization of methyl methacrylate (MMA), styrene and acrylonitrile (AN) onto NR. The graft copolymers can be crosslinked by sulphur and organic accelerators. The crosslinked graft copolymers show improved modulus and hardness in their films compared to NR. However the tensile strength of the films is reduced by grafting. The methods for preparing the graft copolymers, their properties and applications are briefly described

  16. 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.

  17. Toxicological evaluation of natural rubber films from vulcanized latex by the conventional process and the alternative process with ionizing radiation

    International Nuclear Information System (INIS)

    Campos, Vania Elisabeth

    1997-01-01

    The industrial vulcanization of natural rubber latex (NRL) is made all over the world by conventional process using sulphur and heat but it can be made by an alternative process using ionizing radiation. In this research the NRL was tested by 13 physical, chemical and mechanical assays which showed its good quality. It was done a preliminary study of the toxicological properties of 4 natural rubber films obtained by casting process of NRL: one non vulcanized, other vulcanized by the conventional process and two vulcanized by the alternative process. In the alternative process the films were obtained by irradiation of NRL by gamma rays from the 60 Co source at 250 kGy in the absence of sensitizer and irradiated NRL at 12 kGy in the presence of 4ph r of n-butyl acrylate / 0.2 phr of KOH. These vulcanization doses were determined from broken tensile strength. In the conventional process, sulphur vulcanized NRL was made using a classical composition. Another film was made with non vulcanized NRL. The preliminary evaluation of the toxicological properties was made from in vitro cytotoxicity and in vivo systemic toxicity assays. The LBN films vulcanized by the alternative process have less cytotoxicity than the NRL film vulcanized by the conventional process. The sensitized vulcanized films by gamma rays and non vulcanized films showed similar cytotoxicity while the vulcanized films without sensitizer showed a slight lower cytotoxicity. The non vulcanized NRL film and the NRL films vulcanized by the alternative process did not show toxic effects int he 72 hours period of the systemic toxicity assay. However the NRL film vulcanized with sulphur induced effects like allaying and motor in coordination on the animals treated with an oil extract at the fourth hour and recovering after that. The alternative process promoted lower toxic effects than conventional process because there was no toxic substances present. (author)

  18. The Effect of Paraffin Wax to Properties of Radiation Vulcanization Natural Rubber Latex (RVNRL)

    International Nuclear Information System (INIS)

    Mohd Noorwadi Mat Lazim; Sofian Ibrahim; Muhammad Saiful Omar

    2015-01-01

    Dipping factories often encounter a serious problem with high tackiness of the finish products during storage. The tackiness effect can be lead to rejection of products. This tackiness effect of natural (NR) rubber film originates in the free rubber chain ends at the surface of the film. The tackiness is not depends on the degree of crosslinking (vulcanization), since radiation itself unable to reduce the tackiness effect. The RVNRL requires addition of additive or anti-tack agent into formulation to reduce tackiness effect. In this experiment, paraffin wax manufactured by Emulco Sdn Bhd under the trade name Aquawax 48 was added into RVNRL formulation as anti-tack and the effect of paraffin wax to physical and mechanical properties of RVNRL was study. (author)

  19. Grafting

    Energy Technology Data Exchange (ETDEWEB)

    Garnett, J L [New South Wales Univ., Kensington (Australia). School of Chemistry

    1979-01-01

    The unique value of ionizing radiation for the initiation of grafting to backbone polymers is discussed. The principles of the technique are briefly reviewed. The conditions under which free radicals and ions participate in these reactions are examined. Examples of representative grafting processes are considered to illustrate where the technique can be of potential commercial value to a wide range of industries. The general principles of these grafting reactions are shown to be applicable to radiation induced rapid cure technology such as is provided by electron beam processing facilities. Grafting reactions initiated by UV are also treated and shown to be of importance because of the many similarities in properties of the ionizing radiation and UV systems, also the rapid industrial exploitation of EB and sensitized UV processing technology. Possible future trends in radiation grafting are outlined.

  20. Development of Highly Efficient Grafting Technique and Synthesis of Natural Polymer-Based Graft Adsorbent

    Energy Technology Data Exchange (ETDEWEB)

    Ueki, Y; Seko, N; Tamada, M [Japan Atomic Energy Agency, Quantum Beam Science Directorate, Takasaki (Japan)

    2012-09-15

    In the framework of the CRP, Japan has focused on the development of fibrous adsorbents for removal of toxic metal ions and recovery of significant metal ions from industrial wastewater and streaming water. Graft polymerization was carried out by using gamma irradiation facility and electron beam accelerator. Emulsion grafting is a novel topic for synthesis of metal ion adsorbents which are prepared from fibrous trunk polymers such as polyethylene fibre and biodegradable nonwoven fabrics. The emulsion grafting, where monomer micelles are dispersed in water in the presence of surfactant, is a highly efficient and economic grafting technique as compared to general organic solvent system. The resultant cotton-based adsorbent has high adsorption efficiency and high adsorption capacity for Hg, besides, it is biodegradable. Polylactic acid can also be used as a trunk material for the grafting. (author)

  1. Analysis of Gel Permeation Chromatography From Irradiation Copolymer Grafting of Methylmethacrylate on to Natural Rubber

    International Nuclear Information System (INIS)

    Hendrana, Sunit; Purwanto, Indratmoko Hari; Karyaningsih, Ipit; Utama, MargaHerwinarni

    2004-01-01

    Grafting of methyl methacrylate (MMA) onto natural rubber was carried out by γ-irradiation using 60 Co source at dose rate 1 KGy/h and total dose of 5 KGy. Gel permeation chromatography (GPC) was used to analyse the grafting. The GPC's chromatogram, molecular weight and molecular weight distribution data indicate that grafting of MMA onto natural rubber and homo polymerization of MMA are the reaction mostly occurs. Meanwhile, the presence of natural rubber radical with a chain end natural rubber radical affect the PMMA homopolymer occurred

  2. Carboxy terminated rubber based on natural rubber grafted with acid anhydrides and its adhesion properties

    International Nuclear Information System (INIS)

    Klinpituksa, P; Kongkalai, P; Kaesaman, A

    2014-01-01

    The chemical modification of natural rubber by grafting of various polar functional molecules is an essential method, improving the versatility of rubber in applications. This research investigated the preparation of natural rubber-graft-citraconic anhydride (NR-g-CCA), natural rubber-graft-itaconic anhydride (NR-g-ICA), and natural rubber-graft-maleic anhydride (NR-g-MA), with the anhydrides grafted to natural rubber in toluene using benzoyl peroxide as an initiator. Variations of monomer content, initiator content, temperature and reaction time of the grafting copolymerization were investigated. The maximum degrees of grafting were 1.06% for NR-g-CCA, 4.66% for NR-g-ICA, and 5.03% for NR-g-MA, reached using 10 phr citraconic anhydride, 10 phr of itaconic anhydride, or 8 phr of maleic anhydride, 3 phr benzoyl peroxide, at 85, 80 and 80°C for 2, 2 and 3 hrs, respectively. Solvent-based wood adhesives were formulated from these copolymers with various contents of wood resin in the range 10-40 phr. The maximal 289 N/in cleavage peel and 245.7 KPa shear strength for NR-g-MA (5.03% grafting) were obtained at 40 phr wood resin

  3. Radiation degradation of methyl methacrylate grafted natural rubber

    International Nuclear Information System (INIS)

    Perera, M.C.S.

    1998-01-01

    M G rubber is a mixture consisting of the graft copolymer and two home polymers. Natural rubber is known to undergo crosslinking during exposure to high energy radiation where as poly methyl methacrylate is a polymer where high energy radiation causes chain scission. It is interesting to determine how this partially miscible blend of scission and crosslinking polymers will behave under high energy radiation. Dynamic Mechanical Analysis (DMA) was used to study the variations in the glass transition regions during high energy treatment of the polymers. Another techniques that is available to obtain motional information and miscibility of blends is Nuclear Magnetic Resonance Spectroscopy (NMR).The present study is aimed at understanding the changes in the molecular structure of rubber when exposed to high energy radiation. The changes in the dynamic mechanical properties in the glass transition region and solid state NMR were made used of for this investigation. The data obtained from the DMA results were analysed to calculate the radiation chemical yields. The local dynamics were investigated with measurement of carbon relaxation times and molecular structure was studied with focus on the level of intermolecular mixing by proton relaxation times

  4. A study on radiation-induced graft copolymerization of monomer onto natural silk fabric

    International Nuclear Information System (INIS)

    Xiang Zhengyu; Wan Dairong; He Qian

    1995-02-01

    In order to improve the properties of natural silk fabric, the mechanism and method of the radiation induced graft copolymerization of monomers onto natural silk fabric were studied. Three monomers, acrylamide, methylacrylamide and hydroxymethyl acrylamide, were selected for grafting test according to requirements of graft processing. The processing conditions of monomer infusion were studied. The properties of grafted samples were measured. The results are as follows: the rate of weight increasing is 10%∼29%; the rate of thickness increasing is 5%∼20%; the abrupt elasticity rose by 30%; the retarded elasticity rose by 12%; wet elasticity rose by 40%; and the brightness of colour and lustre were improved. It is concluded that while the radiation grafted silk kept its natural characteristics, other properties were improved. It became even chubby and thicker. (4 refs., 3 figs., 3 tabs.)

  5. Silane grafted natural rubber and its compatibilization effect on silica-reinforced rubber tire compounds

    NARCIS (Netherlands)

    Sengloyluan, K.; Sahakaro, K.; Dierkes, W. K.; Noordermeer, J. W.M.

    2017-01-01

    Natural Rubber (NR) grafted with 3-octanoylthio-1-propyltriethoxysilane (NXT) was prepared by melt mixing using 1,1′-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane as initiator at 140 °C with NXT contents of 10 and 20 parts per hundred rubber [phr] and initiator 0.1 phr. The silane grafted on NR

  6. 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...... properties of NRL and synthetic gloves and the role of glove powder. The review shows that NRL medical gloves, when compared with synthetic gloves, tend to be stronger, more flexible and better accepted by clinicians. The introduction of powder-free gloves has been associated with reductions in protein...

  7. Effects on the Physical and Mechanical Properties of Porous Concrete for Plant Growth of Blast Furnace Slag, Natural Jute Fiber, and Styrene Butadiene Latex Using a Dry Mixing Manufacturing Process

    Directory of Open Access Journals (Sweden)

    Hwang-Hee Kim

    2016-01-01

    Full Text Available To evaluate the effects of industrial by-products materials on the performance of porous concrete for plant growth, this study investigated the physical, strength, and freeze/thaw resistances of porous concrete for plant growth, prepared by replacing cement with blast furnace slag powder at 60% by weight, and replacing natural stone aggregates with coarse blast furnace slag aggregates at rates of 0%, 20%, 40%, 60% and 100% by weight. In addition, the effects of adding natural jute fiber and styrene butadiene (SB latex to these concrete mixtures were evaluated. The void ratio, compressive strength, and freeze/thaw resistance of the samples were measured. With increasing replacement rate of blast furnace aggregates, addition of latex, and mixing of natural jute fiber the void ratio of the concrete was increased. Compressive strength decreased as the replacement rate of blast-furnace slag aggregates increased. The compressive strength decreased after 100 freeze/thaw cycles, regardless of the replacement rate of blast furnace slag aggregates or of the addition of natural jute fiber and latex. The addition of natural jute fiber and latex decreased the compressive strength after 100 freeze/thaw cycles. The test results indicate that the control mixture satisfied the target compressive strength of 10 MPa and the target void ratio of 25% at replacement rates of 0% and 20% for blast furnace aggregates, and that the mixtures containing latex satisfied the criteria up to an aggregate replacement rate of 60%. However, the mixtures containing natural jute fiber did not satisfy these criteria. The relationship between void ratio and residual compressive strength after 100 freeze/thaw cycles indicates that the control mixture and the mixtures containing jute fiber at aggregate replacement rates of 20% and 40% satisfied the target void ratio of 25% and the target residual compressive strength of over 80% after 100 freeze/thaw cycles. The mixtures containing

  8. Effects on the Physical and Mechanical Properties of Porous Concrete for Plant Growth of Blast Furnace Slag, Natural Jute Fiber, and Styrene Butadiene Latex Using a Dry Mixing Manufacturing Process.

    Science.gov (United States)

    Kim, Hwang-Hee; Kim, Chun-Soo; Jeon, Ji-Hong; Park, Chan-Gi

    2016-01-29

    To evaluate the effects of industrial by-products materials on the performance of porous concrete for plant growth, this study investigated the physical, strength, and freeze/thaw resistances of porous concrete for plant growth, prepared by replacing cement with blast furnace slag powder at 60% by weight, and replacing natural stone aggregates with coarse blast furnace slag aggregates at rates of 0%, 20%, 40%, 60% and 100% by weight. In addition, the effects of adding natural jute fiber and styrene butadiene ( SB) latex to these concrete mixtures were evaluated. The void ratio, compressive strength, and freeze/thaw resistance of the samples were measured. With increasing replacement rate of blast furnace aggregates, addition of latex, and mixing of natural jute fiber the void ratio of the concrete was increased. Compressive strength decreased as the replacement rate of blast-furnace slag aggregates increased. The compressive strength decreased after 100 freeze/thaw cycles, regardless of the replacement rate of blast furnace slag aggregates or of the addition of natural jute fiber and latex. The addition of natural jute fiber and latex decreased the compressive strength after 100 freeze/thaw cycles. The test results indicate that the control mixture satisfied the target compressive strength of 10 MPa and the target void ratio of 25% at replacement rates of 0% and 20% for blast furnace aggregates, and that the mixtures containing latex satisfied the criteria up to an aggregate replacement rate of 60%. However, the mixtures containing natural jute fiber did not satisfy these criteria. The relationship between void ratio and residual compressive strength after 100 freeze/thaw cycles indicates that the control mixture and the mixtures containing jute fiber at aggregate replacement rates of 20% and 40% satisfied the target void ratio of 25% and the target residual compressive strength of over 80% after 100 freeze/thaw cycles. The mixtures containing latex and aggregate

  9. Latex improvement of recycled asphalt pavement

    Science.gov (United States)

    Drennon, C.

    1982-08-01

    The performance of a single unmodified milled recycled asphalt concrete was compared to milled asphalt concrete modified by addition of three types of rubber latex. Latex was added at 2, 3, 5, and 8 percent latex by weight of asphalt in the asphalt concrete. Lattices used were a styrene butadiene (SBR), a natural rubber (NR), an acrylonitrile butadiene (NBR), and four varieties of out of specification SBR lattices. Marshall tests, while indecisive, showed a modest improvement in properties of SBR and NR added material at 3 and 5 percent latex. Addition of NBR latex caused deterioration in Marshall stability and flow over that of control. Repeated load tests were run using the indirect tensile test, analyzed by the VESYS program, which computes life of pavements. Repeated load tests showed improvement in asphalt concrete life when 3 and 5 percent SBR was added. Improvement was also shown by the out of specification SBR.

  10. Silane grafted natural rubber and its compatibilization effect on silica-reinforced rubber tire compounds

    Directory of Open Access Journals (Sweden)

    K. Sengloyluan

    2017-12-01

    Full Text Available Natural Rubber (NR grafted with 3-octanoylthio-1-propyltriethoxysilane (NXT was prepared by melt mixing using 1,1′-di(tert-butylperoxy-3,3,5-trimethylcyclohexane as initiator at 140 °C with NXT contents of 10 and 20 parts per hundred rubber [phr] and initiator 0.1 phr. The silane grafted on NR molecules was confirmed by Fourier transform infrared (FTIR, proton nuclear magnetic resonance (1H-NMR and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM-EDX. Based on 1H-NMR, the use of 10 and 20 phr (parts per hundred resin of silane resulted in grafted NXT onto NR of 0.66 and 1.32 mol%, respectively, or a grafting efficiency of approx. 38%. The use of NXT-grafted NR as compatibilizer in silica-filled NR compounds, to give a total amount of NXT in both grafted and non-grafted forms in the range of 0.8–6.1 wt% relative to the silica, decreases the Mooney viscosity and Payne effect of the compounds, improves filler-rubber interaction, and significantly increases the tensile properties of the silica-filled NR-compounds compared to the non-compatibilized one. At the same silane-content, the use of silane-grafted NR gives slightly better properties than the straight use of the same silane. With sulfur compensation, the use of NXT-grafted-NR with about 6 wt% NXT relative to the silica gives technical properties that reach the levels obtained for straight use of bis-(3-triethoxysilyl-propyltetrasulfide (TESPT at 8.6 wt% relative to the silica.

  11. Antibiotic Modification of Native Grafts: Improving upon nature's scaffolds

    Science.gov (United States)

    Ketonis, Constantinos

    The use of allograft bone in orthopaedics, spine surgery and dentistry is invaluable for helping restore bone defects and promote osteointegration. However, one, and perhaps the most important, problem associated with the use of allograft is infection. It is a devastating complication for patients and physicians alike, and necessitates repeated surgeries, extended treatment and often times results in increased morbidity and poor outcomes. Previous attempts to incorporate antibiotics into allograft by soaking the graft in antibiotic solution have enjoyed limited success in providing adequate protection against bacterial colonization. To overcome problems associated with controlled release systems, I have described a novel chemical modification that allows for the attachment of vancomycin, or other antibiotics, to free amines of allograft bone thus rendering the graft bactericidal over a long time period. This modification, as evaluated by immunohistochemistry, allowed for the uniform and stable attachment of antibiotics to allograft without adversely affecting its potential for incorporation with bone. Modified allograft, placed in the presence of S. aureus, did not allow colonization by bacteria as evaluated by fluorescent imaging, scanning microscopy, and direct bacterial counts. More importantly, inhibition of bacterial colonization resulted in prevention of biofilm formation. Furthermore, I show that the spectrum of activity of the parent antibiotic was maintained, as the construct was not active against E. coli challenges. Comparison of this technology with simple antibiotic incorporation demonstrated that the covalently-coupled antibiotic did not elute from the bone, but rather remained attached and active on the surface for times out to one year, times that are far longer than currently can be achieved with the elution technologies. Despite its potent activity against bacteria, modified bone remained biocompatible allowing attachment of osteoblastic

  12. Type I allergy to natural rubber latex and type IV allergy to rubber chemicals in health care workers with glove-related skin symptoms.

    Science.gov (United States)

    Nettis, E; Assennato, G; Ferrannini, A; Tursi, A

    2002-03-01

    It has been established that there are type I and type IV allergens in latex gloves. The purpose of the study was to establish the prevalence of rubber glove-induced skin symptoms among health care workers in one Italian hospital. Health care workers (n = 1584) were evaluated using a written questionnaire and 295 respondents with glove-induced skin symptoms were tested. We performed: skin prick test with latex glove extract and commercial latex, and environmental and food allergens; glove use test; patch tests with a rubber additive series; and RASTs. Hospital employees who used or had used latex gloves at work were 1294. Three hundred and sixteen (24.4%) reported glove-induced symptoms, namely, cutaneous symptoms in all the cases and non-cutaneous symptoms in 105 subjects (8.1%). Twenty-seven of the 295 symptomatic employees tested (9.1%) were latex sensitive. Thirty-one patients (10.5%) exhibited positive patch test to rubber-related allergens. The most positive readings were obtained from the Thiuram mix and the Carba mix, with 12 and 9 positivities, respectively. The risk factors for latex skin sensitization were: a previous history of atopy and asthma; history of surgery; pre-existing hand dermatitis; work-related symptoms; and positive skin tests to common inhalant and certain foods (P skin complaints of latex gloves are related to skin irritation rather than to allergy. The immediate allergy to latex and the delayed allergy to rubber chemicals suggest that all the health care workers with glove-related dermatitis should undergo both skin prick test and glove use test to detect type I hypersensitivity to latex, and patch test to detect type IV hypersensitivity to rubber chemicals.

  13. Tensile properties of carbon black-filled natural rubber latex films using two different approaches of film preparation

    Science.gov (United States)

    Jarkasi, Siti Aisyah; Samsuri, Azemi; Hashim, M. Y. Amir; Kamarun, Dzaraini

    2017-09-01

    A study was structured to investigate the effects of two different approaches of black-filled NRL films preparation on tensile strengths and tensile stress at 100% strain (M100). In the "First Approach", carbon black dispersion was added into the NRL and mixed using mechanical stirrer. Then the black-filled NRL was coagulated with acetic acid and dried to form NR black-filled masterbatch. This black-filled NR masterbatch was then masticated and mixed with other compounding ingredients on the 2-roll mill. In the "Second Approach", carbon black dispersion was mixed with NRL plus all other compounding ingredients using a mechanical stirrer at high mechanical stirring speed (200 rpm) for 3 hrs. Tensile test-pieces from these two rubber specimens were tested according to ISO37. It was observed that the tensile strengths are affected by both methods. In the case of masticated latex masterbatch, the black-filled NRL films gave higher tensile strength (25-27 MPa) as compared to un-masticated black-filled NRL films (11-17 MPa). The optimum amount of filler loading for highest tensile strength in both approaches was 20 phr of carbon black. However these different approaches did not give significant effect to the elongation at break, EB and M100. SEM images of samples prepared from both approaches suggested that the dispersion of filler in the rubber matrix was better in the masticated samples compared to the un-masticated samples. The reason for the difference in the tensile strength between the two black-filled rubbers might be associated with the degree of dispersions and the uniformity of the dispersions within the rubber matrix. The first mixing approach involved high mechanical shearing action during mastication and mixing process on the 2-roll mill. The high shearing actions were able to breakdown filler aggregates efficiently and distributed the dispersed filler uniformly within the rubber matrix. In the second approach, the breakdown of filler aggregates relied on

  14. Latex in the Hospital Environment

    Science.gov (United States)

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

  15. Technological properties of latex and natural rubber of Hevea brasiliensis clones Propriedades tecnológicas do látex e da borracha natural de clones de Hevea brasiliensis

    Directory of Open Access Journals (Sweden)

    Rogério Manoel Biagi Moreno

    2005-04-01

    Full Text Available Rubber industry has increased the requirements for quality and uniformity of natural rubber produced in Brazil. Technological properties of latex and natural rubber of clones GT 1, PB 235, IAN 873 and RRIM 600 [Hevea brasiliensis (Willd. Former Adr. de Juss. Muell.- Arg] were evaluated by standard methods of the dry rubber content (DRC%, percentage of nitrogen (N% and percentage of ashes (ASH% in two consecutive years; data were correlated with temperature and precipitation. Properties of latex and natural rubber varied (P A indústria da borracha está cada vez mais exigente em relação à qualidade e a uniformidade da borracha natural produzida no Brasil. Neste trabalho as propriedades tecnológicas do látex e da borracha natural dos clones de seringueira GT 1, PB 235, IAN 873 e RRIM 600 [Hevea brasiliensis (Willd. ex Adr. de Juss. Muell.-.Arg] foram avaliadas pelos ensaios padrões do conteúdo de borracha seca (DRC%, porcentagem de nitrogênio (N% e porcentagem de cinzas (CNZ% por dois anos consecutivos; os dados obtidos foram correlacionados com dados de temperatura e precipitação. As propriedades do látex e da borracha natural variaram (P < 0.01 em função do tipo de clone e entre coletas. O DRC% diminuiu no início da estação seca (maio a junho, enquanto N% e CNZ% aumentaram. O período de abril a junho revelou ser crítico, pois os valores da N% oscilaram acima 0,60%, fora dos padrões estabelecidos pela norma técnica brasileira ABNT/NBR. O clone RRIM 600 foi menos suscetível às variações climáticas.

  16. Comparison of the performance of natural latex membranes prepared with different procedures and PTFE membrane in guided bone regeneration (GBR) in rabbits.

    Science.gov (United States)

    Moura, Jonas M L; Ferreira, Juliana F; Marques, Leonardo; Holgado, Leandro; Graeff, Carlos F O; Kinoshita, Angela

    2014-09-01

    This work assessed the performance of membranes made of natural latex extracted from Hevea brasiliensis prepared with three different methods: polymerized immediately after collection without the use of ammonia (L1); polymerized after preservation in ammonia solution (L2); and polymerized after storage in ammonia, followed by Soxhlet technique for the extraction of substances (L3). Polytetrafluoroethylene (PTFE) membrane was used as control. Two 10-mm diameter bone defects were surgically made in the calvaria of thirty adult male New Zealand rabbits. Defects (total n = 60) were treated with guided bone regeneration (GBR) using L1, L2, L3 or PTFE membranes (n = 15 for each membrane). Ten animals were euthanized after 7, 20 and 60 days postoperatively so that five samples (n = 5) of each treatment were collected at each time, and bone regeneration was assessed microscopically. The microscopic analysis revealed defects filled with blood clot and new bone formation at the margins of the defect in all 7-day samples, while 20-day defects were mainly filled with fibrous connective tissue. After 60 days defects covered with L1 membranes showed a significantly larger bone formation area in comparison to the other groups (P PTFE membranes was also investigated in six additional rabbits. The animals were subjected to the same surgical procedure for the confection of one 10-mm diameter bone defect that was treated with L1 (n = 3) or PTFE (n = 3). Fifty-three days later, a second surgery was performed to make a second defect, which was treated with the same type of membrane used in the first surgery. Seven days later, the animals were euthanized and samples analyzed. No differences among L1 and PTFE samples collected from sensitized and non-sensitized animals were found (P > 0.05, Kruskal-Wallis). Therefore, the results demonstrated that latex membranes presented performance comparable to PTFE membranes, and that L1 membranes induced higher bone formation. L1 and

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

    African Journals Online (AJOL)

    Fourteen latex examination gloves (powdered and non-powdered) and five dental rubber dams, representing 6 brands, from five dental academic institutions were analysed for latex allergens and total protein. Total protein content was determined using the BioRad DC protein assay kit and natural rubber allergen levels ...

  18. Effect of epoxidation on 30% poly(methyl methacrylate)-grafted natural rubber polymer electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Nazir, Khuzaimah; Aziz, Ahmad Fairoz [Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia); Adam, Nurul Ilham [Faculty of Applied Sciences, Universiti Teknologi MARA, KampusTapah, 35400 Tapah Road, Tapah, Perak (Malaysia); Yahya, Muhd Zu Azhan [Faculty of Defence Sciences and Technology, Universiti Pertahanan Nasional Malaysia, Kem Sungai Besi, 57000 Kuala Lumpur (Malaysia); Ali, Ab Malik Marwan [Institute of Science, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia)

    2015-08-28

    Epoxidized 30% poly(methyl methacrylate)-grafted natural rubber (EMG 30) as a polymer host in solid polymer electrolytes (SPEs) has been investigated. EMG30 was synthesized via performicepoxidation method onto 30% poly(methyl methacrylate)-grafted natural rubber (MG30) and the formations of epoxy group were discussed. The EMG30 were characterized by proton nuclear magnetic resonance ({sup 1}HNMR) to investigate their chemical structure and differential scanning calorimeter to determine their crystallinity. A new peak in {sup 1}HNMR spectra (2.71 ppm) confirmed the appearance of epoxy group. SPE based on EMG30 doped with 40 wt% LiCF{sub 3}SO{sub 3} show the highest conductivity. The complexation between EMG30 and LiCF{sub 3}SO{sub 3} were confirmed by attenuated total reflection Fourier transform infrared (ATR-FTIR)

  19. Effect of epoxidation on 30% poly(methyl methacrylate)-grafted natural rubber polymer electrolytes

    International Nuclear Information System (INIS)

    Nazir, Khuzaimah; Aziz, Ahmad Fairoz; Adam, Nurul Ilham; Yahya, Muhd Zu Azhan; Ali, Ab Malik Marwan

    2015-01-01

    Epoxidized 30% poly(methyl methacrylate)-grafted natural rubber (EMG 30) as a polymer host in solid polymer electrolytes (SPEs) has been investigated. EMG30 was synthesized via performicepoxidation method onto 30% poly(methyl methacrylate)-grafted natural rubber (MG30) and the formations of epoxy group were discussed. The EMG30 were characterized by proton nuclear magnetic resonance ( 1 HNMR) to investigate their chemical structure and differential scanning calorimeter to determine their crystallinity. A new peak in 1 HNMR spectra (2.71 ppm) confirmed the appearance of epoxy group. SPE based on EMG30 doped with 40 wt% LiCF 3 SO 3 show the highest conductivity. The complexation between EMG30 and LiCF 3 SO 3 were confirmed by attenuated total reflection Fourier transform infrared (ATR-FTIR)

  20. Effect of epoxidation on 30% poly(methyl methacrylate)-grafted natural rubber polymer electrolytes

    Science.gov (United States)

    Nazir, Khuzaimah; Aziz, Ahmad Fairoz; Adam, Nurul Ilham; Yahya, Muhd Zu Azhan; Ali, Ab Malik Marwan

    2015-08-01

    Epoxidized 30% poly(methyl methacrylate)-grafted natural rubber (EMG 30) as a polymer host in solid polymer electrolytes (SPEs) has been investigated. EMG30 was synthesized via performicepoxidation method onto 30% poly(methyl methacrylate)-grafted natural rubber (MG30) and the formations of epoxy group were discussed. The EMG30 were characterized by proton nuclear magnetic resonance (1HNMR) to investigate their chemical structure and differential scanning calorimeter to determine their crystallinity. A new peak in 1HNMR spectra (2.71 ppm) confirmed the appearance of epoxy group. SPE based on EMG30 doped with 40 wt% LiCF3SO3 show the highest conductivity. The complexation between EMG30 and LiCF3SO3 were confirmed by attenuated total reflection Fourier transform infrared (ATR-FTIR).

  1. Liberação de componentes do extrato de Casearia sylvestris Swartz empregando membranas de látex natural como suporte

    OpenAIRE

    Trecco, Alberto [UNESP; Borges, Felipe Azevedo [UNESP; Perri, Elaíse G. [UNESP; Santos, André Gonzaga dos [UNESP; Chin, Chung Man [UNESP; Herculano, Rondinelli Donizetti [UNESP

    2014-01-01

    Natural Rubber Latex (NRL) membrane, made from latex extracted from the rubber tree Hevea brasiliensis, has shown great potential for use in the biomedicine and biomaterials area. Thanks to its biocompatibility and low rejection rate, it has been used for implants and grafts, acting as a stimulant of angiogenesis and cell adhesion and as a barrier against infectious agents. Besides these applications, the membranes are used as model release systems, to assess the release behavior of drugs and...

  2. Application of recombinant latex allergens in diagnostics of occupational latex allergy

    Directory of Open Access Journals (Sweden)

    Ewa Nowakowska-Świrta

    2015-02-01

    Full Text Available Over many years, allergy to natural rubber latex has been a major problem among health care workers (HCW. The diagnosis of occupational allergy requires methods of high diagnostic accuracy in view of certification implications (e.g., a sick worker quits a job. With the development of molecular methods, the frequency of application of recombinant allergens in the diagnostics of allergic diseases continues to increase. This paper reviews the applicability of laboratory tests which use recombinant allergens in the diagnostics of occupational allergy. The diagnosis of latex allergy is based on the presence of clinical symptoms linked with exposure to latex allergens, positive skin prick tests and detection of specific IgE antibodies to latex in serum. Moreover, in some cases specific challenge tests are conducted. The analysis of literature indicates that applying the panel of recombinant latex allergens in diagnostic tests, cross-reactivity can very likely be excluded and/or sensitization can be confirmed without the need for specific challenge tests, which in case of latex allergens carries a potential risk of generalized reactions. Med Pr 2015;66(1:85–97

  3. Aluminum uptake from natural waters by a radiation-grafted membrane

    Energy Technology Data Exchange (ETDEWEB)

    Bazante-Yamaguishi, Renata; Moura, Eduardo; Manzoli, Jose E.; Geraldo, Aurea B.C., E-mail: ageraldo@ipen.br, E-mail: ryamaguishi@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    Styrene grafted, chemically modified polymeric membranes were used to carry off aluminum of drinking water from wells located at Billings dam region. The membranes comprised polymeric substrates of PVC (polyvinylchloride) and PP (polypropylene), which were mutually grafted with gamma radiation. The chemical modification included three basic reaction paths: Friedel-Crafts acylation, 2-methylanisole coupling and a final oxidation; this modification enables aluminum selectivity on the membrane. This chemical process inserts a salicylated derivative bonded onto the aromatic ring of styrene; such molecular arrangement is responsible for complexation of aluminum ions. The aluminum sorption capacity of these membranes was evaluated firstly from an aluminum control solution, where parameters like the ideal pH value for aluminum sorption and the interfering species were studied and correlated to know the best conditions for aluminum uptake. Later, the membranes were used for aluminum remediation of natural waters (real-life samples). The applicability results and limits are then discussed. (author)

  4. Aluminum uptake from natural waters by a radiation-grafted membrane

    International Nuclear Information System (INIS)

    Bazante-Yamaguishi, Renata; Moura, Eduardo; Manzoli, Jose E.; Geraldo, Aurea B.C.

    2013-01-01

    Styrene grafted, chemically modified polymeric membranes were used to carry off aluminum of drinking water from wells located at Billings dam region. The membranes comprised polymeric substrates of PVC (polyvinylchloride) and PP (polypropylene), which were mutually grafted with gamma radiation. The chemical modification included three basic reaction paths: Friedel-Crafts acylation, 2-methylanisole coupling and a final oxidation; this modification enables aluminum selectivity on the membrane. This chemical process inserts a salicylated derivative bonded onto the aromatic ring of styrene; such molecular arrangement is responsible for complexation of aluminum ions. The aluminum sorption capacity of these membranes was evaluated firstly from an aluminum control solution, where parameters like the ideal pH value for aluminum sorption and the interfering species were studied and correlated to know the best conditions for aluminum uptake. Later, the membranes were used for aluminum remediation of natural waters (real-life samples). The applicability results and limits are then discussed. (author)

  5. 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

  6. 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

  7. Ultraviolet curing of acrylated liquid natural rubber for surface coating application

    OpenAIRE

    Kannikar Kwanming; Pairote Klinpituksa; Wae-asae Waehamad

    2009-01-01

    Ultraviolet curable acrylated liquid natural rubber was prepared by grafting of photosensitive molecule onto liquid natural rubber for surface coating application. The liquid natural rubber (LNR) was firstly obtained by degradation of natural rubber latex with hydrogen peroxide and cobalt acetylacetonate at 65oC for 72 hrs. The preparation of acrylated natural rubber was carried out by the reaction of acrylic acid and epoxidized liquid natural rubber (ELNR) prior obtained from LNR with formic...

  8. Effect of the [TiO{sub 2}] on the radiation attenuation properties on the human tissue simulator obtained from radiovulcanized natural rubber latex; Efeito da [TiO{sub 2}] nas propriedades de atenuacao da radiacao no simulador de tecido humano obtido do latex de borracha natural radiovulcanizado

    Energy Technology Data Exchange (ETDEWEB)

    Tomimasu, Sumie; Guedes, Selma Matheus Loureiro [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Centro de Tecnologia das Radiacoes]. E-mail: smguedes@net.ipen.br

    2002-07-01

    In this paper was studied the concentration effect of TiO{sub 2} used as filler in the radiation attenuation properties of human tissue simulator obtained from radio vulcanized natural rubber. The studied parameters were the following: the mass stopping power (S{sub mas}), the depth at maximum dose (Z{sub max}), the depth at 50% of maximum dose (R{sub 50}) the radiotherapeutic range (RR{sub 80}) and the electrons range (R). The natural rubber latex was formulated with [n-butyl acrylate ] = e phr and [KOH] = 0,2 phr and radio vulcanized by gamma rays (10 kGy) from {sup 60} Co source. The filler TiO{sub 2} was added (0-16 phr). The natural rubber slabs were obtained by casting method and theirs absorbed dose behavior was studied for each filler concentration using electrons beam (6 MeV) from an accelerator. The results showed that the addition of each phr of filler promoted the decrease of 0.019 cm for Z{sub max}, 0.021 cm for RR{sub 80}, 0.033 cm for R and 0.026 cm for R{sub 50} up to [Ti O{sub 2}] 15 phr. The S{sub mas} increased from 1.72 MeVcm2g-1 to 2.00 MeVcm2g-1 in the filler concentration range of 0-16 phr. The filler must be used in the 12-15 phr range. (author)

  9. Grafted natural polymer as new drag reducing agent: An experimental approach

    Directory of Open Access Journals (Sweden)

    Abdulbari Hayder A.

    2012-01-01

    Full Text Available The present investigation introduces a new natural drag reducing agent which has the ability to improve the flow in pipelines carrying aqueous or hydrocarbon liquids in turbulent flow. Okra (Abelmoschus esculentus mucilage drag reduction performance was tested in water and hydrocarbon (gas-oil media after grafting. The drag reduction test was conducted in a buildup closed loop liquid circulation system consists of two pipes 0.0127 and 0.0381 m Inside Diameter (ID, four testing sections in each pipe (0.5 to 2.0 m, tank, pump and pressure transmitters. Reynolds number (Re, additive concentration and the transported media type (water and gas-oil, were the major drag reduction variables investigated. The experimental results show that, new additive drag reduction ability is high with maximum percentage of drag reduction (%Dr up to 60% was achieved. The experimental results showed that the drag reduction ability increased by increasing the additive concentration. The %Dr was found to increase by increasing the Re by using the water-soluble additive while it was found to decrease by increasing the Re when using the oil-soluble additive. The %Dr was higher in the 0.0381 m ID pipe. Finally, the grafted and natural mucilage showed high resistance to shear forces when circulated continuously for 200 seconds in the closed-loop system.

  10. Toxicological evaluation of natural rubber films from vulcanized latex by the conventional process and the alternative process with ionizing radiation; Avaliacao toxicologica de filmes de borracha natural obtidos do latex vulcanizado pelo processo convencional e pelo processo alternativo com radiacao ionizante

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Vania Elisabeth

    1997-07-01

    The industrial vulcanization of natural rubber latex (NRL) is made all over the world by conventional process using sulphur and heat but it can be made by an alternative process using ionizing radiation. In this research the NRL was tested by 13 physical, chemical and mechanical assays which showed its good quality. It was done a preliminary study of the toxicological properties of 4 natural rubber films obtained by casting process of NRL: one non vulcanized, other vulcanized by the conventional process and two vulcanized by the alternative process. In the alternative process the films were obtained by irradiation of NRL by gamma rays from the {sup 60} Co source at 250 kGy in the absence of sensitizer and irradiated NRL at 12 kGy in the presence of 4ph r of n-butyl acrylate / 0.2 phr of KOH. These vulcanization doses were determined from broken tensile strength. In the conventional process, sulphur vulcanized NRL was made using a classical composition. Another film was made with non vulcanized NRL. The preliminary evaluation of the toxicological properties was made from in vitro cytotoxicity and in vivo systemic toxicity assays. The LBN films vulcanized by the alternative process have less cytotoxicity than the NRL film vulcanized by the conventional process. The sensitized vulcanized films by gamma rays and non vulcanized films showed similar cytotoxicity while the vulcanized films without sensitizer showed a slight lower cytotoxicity. The non vulcanized NRL film and the NRL films vulcanized by the alternative process did not show toxic effects in the 72 hours period of the systemic toxicity assay. However the NRL film vulcanized with sulphur induced effects like allaying and motor in coordination on the animals treated with an oil extract at the fourth hour and recovering after that. The alternative process promoted lower toxic effects than conventional process because there was no toxic substances present. (author)

  11. Development of a water purifier for radioactive cesium removal from contaminated natural water by radiation-induced graft polymerization

    Science.gov (United States)

    Seko, Noriaki; Hoshina, Hiroyuki; Kasai, Noboru; Shibata, Takuya; Saiki, Seiichi; Ueki, Yuji

    2018-02-01

    Six years after the Fukushima-nuclear accident, the dissolved radioactive cesium (Cs) is now hardly detected in environmental natural waters. These natural waters are directly used as source of drinking and domestic waters in disaster-stricken areas in Fukushima. However, the possibility that some radioactive Cs adsorbed on soil or leaves will contaminate these natural waters during heavy rains or typhoon is always present. In order for the returning residents to live with peace of mind, it is important to demonstrate the safety of the domestic waters that they will use for their daily life. For this purpose, we have synthesized a material for selective removal of radioactive Cs by introducing ammonium 12-molybdophosphate (AMP) onto polyethylene nonwoven fabric through radiation-induced emulsion graft polymerization technique. Water purifiers filled with the grafted Cs adsorbent were installed in selected houses in Fukushima. The capability of the grafted adsorbent to remove Cs from domestic waters was evaluated for a whole year. The results showed that the tap water filtered through the developed water purifier contained no radioactive Cs, signifying the very effective adsorption performance of the developed grafted adsorbent. From several demonstrations, we have commercialized the water purifier named "KranCsair®". Furthermore, we have also developed a method for the mass production of the grafted nonwoven fabric. Using a 30 L grafting reactor, it was possible to produce the grafted nonwoven fabric with a suitable range of degree of grafting. When an irradiated roll of nonwoven trunk fabric with a length of 10 m and a width of 30 cm was set in the reactor filled with glycidyl methacrylate (GMA), AMP, Tween 80 monomer emulsion solution at 40 °C for 1 h, the difference of Dgs in the length and the width on roll of fabrics was negligible.

  12. 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.

  13. 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.

  14. 2,2,2-Trifluoroethyl methacrylate-graft-natural rubber: Synthesis and application as compatibilizer in natural rubber/fluoroelastomer blends

    Energy Technology Data Exchange (ETDEWEB)

    Hinchiranan, N., E-mail: nhn78@hotmail.com [Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Wannako, P. [Program in Petrochemistry and Polymer Science, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Paosawatyanyong, B. [Department of Physics, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Prasassarakich, P. [Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand)

    2013-05-15

    The incompatibility and immiscibility of natural rubber (NR)/fluoroelastomers (FKM) blends were improved by incorporation of a graft copolymer synthesized from the free radical graft copolymerization of 2,2,2-trifluoroethyl methacrylate (TFEM) onto NR initiated by benzoyl peroxide via a melt-mixing process. The grafting properties were investigated as functions of the initiator and monomer concentrations, reaction temperature and time. At the optimal conditions, the obtained graft NR (GNR) purified by Soxhlet extraction contained a maximum grafting efficiency of 1.34% with 49.1% monomer conversion. The structure of the purified GNR was analyzed using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and nuclear magnetic resonance spectroscopy ({sup 1}H NMR and {sup 19}F NMR). The gross GNR was then applied as the compatibilizer for NR/FKM vulcanizates (20/80 (w/w)) cured by peroxide vulcanization. The addition of GNR at 15 parts per hundred of rubber (phr) gave a vulcanizate with the highest tensile strength (9.93 MPa), some 5.31-fold higher than that of the incompatibilized one (1.87 MPa). This is likely to be due to the higher degree of homogeneity of the constituent phases in the GNR-compatibilized blends, as observed by scanning electron microscopy (SEM). The GNR-compatibilized NR/FKM vulcanizates were also resistant to gasohol E85 (85% (w/w) of ethanol). Highlights: ► 2,2,2-Trifluoroethyl methacrylate could be grafted on NR via melt-mixing process. ► Effect of grafting parameters on grafting efficiency and gel content was observed. ► NR/FKM containing graft NR had higher tensile strength than uncompatibilized ones. ► The compatibilized NR/FKM vulcanizates had higher gasohol-swelling resistance.

  15. A study of using polythiol compounds and 2-ethyl-hexyl-acrylate with carbon tetrachloride as sensitizers for radiation vulcanization of natural rubber latex

    International Nuclear Information System (INIS)

    Polsuksiri, C.

    1989-01-01

    Experiments on using 3 different compounds of polythiol and an acrylate as sensitizer for radiation vulcanization were conducted. It was found that 1,4 butane diol propane tris-3-mercapto propionate showed the tendency to be a good sensitizer. The tensile strength of the rubber film prepared from the irradiated latex was found to be 14 MPa at sensitizer concentration of 1 phr and radiation dose of 45 kGy. As for 2-ethyl hexyl acrylate (2EHA), the maximum tensile strength of rubber film was found to be 23 MPa at concentration of 3 phr and radiation dose of 35 kGy. The mixture of 2 EHA and CCl 4 at various ratio was also used as sensitizer. The optimum ratio was found to be 5:1 at concentration of 6 phr and radiation dose of 15 kGy. The maximum tensile strength was as high as 25 MPa. The study also revealed that the radiation vulcanized latex with crosslink density of about 18x10 18 C.L./cm 3 would give the rubber film of highest tensile strength

  16. The effect of natural sounds on the anxiety of patients undergoing coronary artery bypass graft surgery

    Directory of Open Access Journals (Sweden)

    Mohammad Javad Amiri

    2017-11-01

    Full Text Available Abstract Background This study aims to investigate the effect of natural sounds on the anxiety of patients undergoing coronary artery bypass graft surgery (CABG. Methods In this clinical trial, 90 patients, who were candidates for CABG in an urban area of Iran, were selected and randomly assigned to intervention and control groups by the minimization method. In the intervention group, natural sounds were broadcast through headphones for 30 min. In the control group, headphones connected to a silent device were used. The research instruments were a demographic questionnaire and the Spielberger State-Trait Anxiety Inventory (STAI. These were used before the intervention, 30 min after the music, and before the surgery in the waiting room for both groups. Data was analyzed using SPSS software. Results The mean anxiety level of the intervention group has been found to be significantly lower than that of the control group half an hour after the intervention as well as in the waiting room in the preoperative period (p = 0.001. Moreover, the mean anxiety of the intervention group decreases, while it increases for the control group over time (p < 0.001. Conclusion Natural sounds can be used as a non-pharmacological way to reduce the anxiety of patients undergoing CABG. Trial registration I RCT2017011723190N3 , Registered 1 March 2017.

  17. NR based curred latex material reclaimed with 2,2'-dibenzamidodiphenyldisulphide in truck tyre tread compound

    NARCIS (Netherlands)

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

    2006-01-01

    It is observed that reclamation of natural rubber latex based rubber using 2,2'-dibenzamidodiphenyldisulphide as reclaiming agent is an optional methodology for recycling of waste latex rubber (WLR). For progressive replacement of virgin natural rubber by the reclaim, two alternatives curing system

  18. Hydroquinone and quinone-grafted porous carbons for highly selective CO2 capture from flue gases and natural gas upgrading

    NARCIS (Netherlands)

    Wang, J.; Krishna, R.; Yang, J.; Deng, S.

    2015-01-01

    Hydroquinone and quinone functional groups were grafted onto a hierarchical porous carbon framework via the Friedel-Crafts reaction to develop more efficient adsorbents for the selective capture and removal of carbon dioxide from flue gases and natural gas. The oxygen-doped porous carbons were

  19. Physical and chemical characteristics of Vietnamese natural corals used as substitutes for bone grafts

    International Nuclear Information System (INIS)

    Tran Cong Toai; To Phuong Vu; Tran Bac Hai; Doan Binh

    1999-01-01

    Coral has been used as substitutes for bone grafts in France and the United State of American. In Vietnam, research on coral has been done at the Biomaterial Research Laboratory, The University Training Centre since 1994. Among the studies are the determination of physical and chemical characteristics of natural coral blocks obtained by the scientists of the NhaTrang Maritime Institute. We found that it was quite necessary to establish a standard formula for processing coral as biomaterial graft. The selected coral was cut into blocks approximately 1x1x1 cm or 1x1x2 cm and cleaned. We measured the density, porous rate, water loading speed (at room temperature and at boiled temperature with low pressure, mechanical strength and content of soluble protein, chitosan in coral rods. (1140 samples of three types of corals). The density of Porites australiensis was heavier than that of Porites lutea. But, Porites lutea has more porous rate than Porites australiensis. This experiment has also showed that mechanical strength of Porites australiensis was harder than that of Porites lutea. To measure the water loading speed, the coral rods were treated at boiled temperature with low pressure versus at room temperature. We found that the water loading speed of Porites australiensis at boiled temperature was faster than that at room temperature. Porites lutea and Montastrea annuligera showed as the same result. The efficiency of water loading rate is quite low approximately 116 - 121 % for 45 minutes at room temperature versus 135 - 155 % for only I 0 minutes at boiled temperature with low pressure. We measured the content of soluble protein by both Lowry and Biuret methods, the content of soluble protein after washing with 0.9% sodium chloride, 1210 degree C, 60 minutes is very low (below limit of tests). The content of chitosan from dried coral rods treated with HCI 36 - 38 % and NAOH 0.01N is about 0.1 - 0.6 %. Our study determined some physical and chemical characteristics

  20. Latex allergy and filaggrin null mutations

    DEFF Research Database (Denmark)

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

    2011-01-01

    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...... in the cases in this study may not have occurred through direct skin contact but through the respiratory organs via latex proteins that are absorbed in glove powder and aerosolized...

  1. Latex allergies - for hospital patients

    Science.gov (United States)

    ... ency/patientinstructions/000499.htm Latex allergies - for hospital patients To use the sharing features on this page, ... ADAM Health Solutions. About MedlinePlus Site Map FAQs Customer Support Get email updates Subscribe to RSS Follow ...

  2. Polymer Gel Electrolytes Based on 49 % Methyl-Grafted Natural Rubber

    International Nuclear Information System (INIS)

    Kamisan, A.S.; Kudin, T.I.T.; Ali, A.M.M.; Yahya, M.Z.A.; Yahya, M.Z.A.

    2011-01-01

    Polymer gel electrolytes (PGEs) based on 49 % methyl-grafted natural rubber (MG49) were first prepared by dissolving ammonium triflate (NH 4 CF 3 SO 3 ) in propylene carbonate (PC) by various molar concentrations of NH 4 CF 3 SO 3 to obtain liquid electrolytes and were characterized by AC electrical impedance spectroscopy (EIS) measurements to study their conducting behaviour. The liquid electrolyte with optimum conductivity (0.7 M) was then gelled with MG49 and their conductivity was also studied. The highest conductivity of liquid electrolyte was 3.6 x 10 -3 Scm -1 and 2.9x10 -2 Scm -1 for PGEs. The molecular interactions between components of NH 4 CF 3 SO 3 , PC, and MG49 have been observed by ATR-FTIR spectroscopy study. The downshifting of C=O stretching frequency of PC from 1785 cm -1 to 1780 cm -1 and NH 4+ band from 1634 cm -1 to 1626 cm -1 that has been obtained by spectroscopic data in addition of NH 4 CF 3 SO 3 confirmed the complexation occurrence. Interaction between NH 4 CF 3 SO 3 and MG49 has also been investigated. This study is focused on the interactions between components in the PGE system and relates them with their conducting behavior. (author)

  3. Morphological Study on Room-Temperature-Cured PMMA-Grafted Natural Rubber-Toughened Epoxy/Layered Silicate Nanocomposite

    OpenAIRE

    Yuhana, N. Y.; Ahmad, S.; Kamal, M. R.; Jana, S. C.; Bahri, A. R. Shamsul

    2012-01-01

    A morphological study was conducted on ternary systems containing epoxy, PMMA-grafted natural rubber, and organic chemically modified montmorillonite (Cloisite 30B). Optical microscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and wide-angle X-ray diffraction (WAXD) analysis were used. The following four materials were prepared at room temperature: cured unmodified epoxy, cured toughened epoxy, cured unmodified epoxy/Cloisite 3...

  4. Grafted NiO on natural olivine for dry reforming of methane

    Directory of Open Access Journals (Sweden)

    Grafted NiO on natural olivine for dry reforming of methane C Courson, L Udron, C Petit and A Kiennemann Sci. Technol. Adv. Mater. 3 No 3 (June 2002 271-282 Abstract | References Full text: Acrobat PDF (1.10 MB

    2002-01-01

    Full Text Available Natural olivine is used for gasification of biomass in a fluidised bed. Characterisations by X-ray diffraction and electron microscopies (SEM and TEM have proved the presence of a (Mg,Fe2SiO4 structure (Mg/Fe ratio: 9/1 with a rather broad distribution in elemental composition. Temperature programmed reduction has revealed equally the presence of iron oxides outside of this structure. The nature of free iron oxides can be both modified by increasing the temperature of calcination and confirmed by measurements of magnetism.The introduction of nickel oxide upon natural olivine is obtained by impregnation with a nitrate salt. The type of interaction of nickel oxide with olivine is different depending upon the preparation method and the calcination temperature. For calcination at 1100 °C, the effects of the amount of NiO and the number of impregnation have been studied. At a high temperature of calcination (1400 °C, NiO is integrated into the olivine structure and the amount of free iron increases. Integrated NiO on olivine is non-reducible, resulting in an inactive catalyst. At lower calcination temperatures grafted NiO is formed, a species which is reduced under catalytic test conditions without aggregation of particles. A single impregnation of nickel (5.5 wt% of NiO gives a stable catalyst activated directly under reaction conditions (CH4+CO2 yielding 96% CO and 76% H2. Catalysts with lower amounts of NiO or a double impregnation of nickel salt lead to a less stable system.Analysis reveals that no change in olivine structure nor size of nickel deposit occurs under test conditions. Equally there are no carbon deposits formed on these catalysts. A model of the evolution of each catalytic system arising from the different preparation methods is proposed. The observed deactivation of such catalysts is attributed to the increase in the amount of free iron, which favours the oxidative properties of the catalytic system.

  5. Hydroquinone and Quinone-Grafted Porous Carbons for Highly Selective CO2 Capture from Flue Gases and Natural Gas Upgrading.

    Science.gov (United States)

    Wang, Jun; Krishna, Rajamani; Yang, Jiangfeng; Deng, Shuguang

    2015-08-04

    Hydroquinone and quinone functional groups were grafted onto a hierarchical porous carbon framework via the Friedel-Crafts reaction to develop more efficient adsorbents for the selective capture and removal of carbon dioxide from flue gases and natural gas. The oxygen-doped porous carbons were characterized with scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, and Raman spectroscopy. CO2, CH4, and N2 adsorption isotherms were measured and correlated with the Langmuir model. An ideal adsorbed solution theory (IAST) selectivity for the CO2/N2 separation of 26.5 (298 K, 1 atm) was obtained on the hydroquinone-grafted carbon, which is 58.7% higher than that of the pristine porous carbon, and a CO2/CH4 selectivity value of 4.6 (298 K, 1 atm) was obtained on the quinone-grafted carbon (OAC-2), which represents a 28.4% improvement over the pristine porous carbon. The highest CO2 adsorption capacity on the oxygen-doped carbon adsorbents is 3.46 mmol g(-1) at 298 K and 1 atm. In addition, transient breakthrough simulations for CO2/CH4/N2 mixture separation were conducted to demonstrate the good separation performance of the oxygen-doped carbons in fixed bed adsorbers. Combining excellent adsorption separation properties and low heats of adsorption, the oxygen-doped carbons developed in this work appear to be very promising for flue gas treatment and natural gas upgrading.

  6. Tensile and morphology properties of PLA/LNR blends modified with maleic anhydride grafted-polylactic acid and -natural rubber

    Science.gov (United States)

    Ruf, Mohd Farid Hakim Mohd; Ahmad, Sahrim; Chen, Ruey Shan; Shahdan, Dalila; Zailan, Farrah Diyana

    2018-04-01

    This research was carried out to investigate the addition of grafted copolymers of maleic anhydride grafted-polylactic acid(PLA-g-MA) and maleic anhydride grafted-natural rubber (NR-g-MA) on the tensile and morphology properties of polylactic acid/ liquid natural rubber (PLA/LNR) blends. Prior to blend preparation, the PLA-g-MA and NR-g-MA was first self-synthesized using maleic anhydride (MA) and dicumyl peroxide (DCP) as initiator together with the PLA and NR respectively. The PLA/LNR, PLA/LNR/PLA-g-MA and PLA/LNR/NR-g-MA blends were prepared via melt-blending method. The loading of PLA-g-MA and NR-g-MA was varied by 5, 10 and 15 wt% respectively. The addition of PLA-g-MA led to increment in tensile strength with 5 and 10 wt% while NR-g-MA gives lower than controlled sample (PLA/LNR blend). Scanning electron microscope (SEM) showed the interaction of the components in the blends. The PLA/LNR compatibilized with PLA-g-MA and NR-g-MA shows greater dispersion and adhesion.

  7. Encapsulation of Clay Platelets inside Latex Particles

    NARCIS (Netherlands)

    Voorn, D.J.; Ming, W.; Herk, van A.M.; Fernando, R.H.; Sung, Li-Piin

    2009-01-01

    We present our recent attempts in encapsulating clay platelets inside latex particles by emulsion polymerization. Face modification of clay platelets by cationic exchange has been shown to be insufficient for clay encapsulation, leading to armored latex particles. Successful encapsulation of

  8. Antibacterial activity of the latex of Argemone ochroleuca Sweet

    International Nuclear Information System (INIS)

    Saad A. Alamri; Mahmoud F. Moustafa

    2010-01-01

    To investigate the antibacterial effect of the crude latex of Argemone ochroleuca (A. ochroleuca) as antibacterial potential against a range of human pathogenic bacteria. This study was carried out at King Khalid University, Abha, Kingdom of Saudi Arabia from January to March 2010. Seventeen ml of fresh latex from A. ochroleuca Sweet was collected, and the antibacterial activity of crude and diluted latex were examined using one ml of standardized inoculum suspension, and using the agar diffusion method test against Bacillus subtilis, Enterobacter aerogenes, Micrococcus luteus, Escherichia coli, and Staphylococcus aureus. All inoculated plates were incubated aerobically at 290C for 48 hours. The diameter of the zones of inhibition was measured to the nearest mm. The crude latex of A. ochroleuca exhibited a potent antibacterial effect on all bacterial strains examined. The zones of inhibition against the tested bacteria were found in the range of 9.30 - 40.3 mm along with their respective minimum inhibitory concentration values 100 ul/ml. The observable inhibition on selected bacteria by latex of A. ochroleuca makes it a promising alternative as a potential source of natural antibacterial (Author).

  9. Improvement of Thermo-Mechanical Properties of Short Natural Fiber Reinforced Recycled Polypropylene Composites through Double Step Grafting Process

    Science.gov (United States)

    Saputra, O. A.; Rini, K. S.; Susanti, T. D.; Mustofa, R. E.; Prameswari, M. D.; Pramono, E.

    2017-07-01

    This study focused on the effect of a compatibilizer addition, maleic anhydrides (MAH) on mechanical, thermal and water absorption properties of oil palm empty fruit bunches (EFB) fiber reinforced recycled polypropylene (rPP) biocomposites. The double steps grafting process were conducted by incorporated MAH on both rPP and EFB to improve the surface adhesion between these materials, to result in a good mechanical properties as well as biocompatibility to nature. The chemical test was carried out using FTIR (Fourier Transform Infra-Red) spectroscopy technique to evaluated grafting process. The mechanical test was investigated and found that the addition of 10 phr MAH to both rPP and EFB improved mechanical strength of the biocomposites higher than another formulas. In this study, thermal properties of biocomposites also characterized. Water absorption (WA) analysis showed the presence of EFB fiber increased the water uptake of the material.

  10. Studies on the nature of the incompatibility in a cucurbitaceous graft

    NARCIS (Netherlands)

    Stigter, de H.C.M.

    1956-01-01

    Musk melon (M), cucumber (C) and Cucurbita ficifolia (F) could succesfully be grafted in all single combinations, except for M/F which required foliage on the stock to survive. Defoliation of this stock caused the plant to wilt and die, generally in 4-5 days; necrosis started in the stock: a rapid

  11. The nature of the initiating centres for grafting in air-irradiated perfluoro polymers

    International Nuclear Information System (INIS)

    Bozzi, A.; Chapiro, A.

    1987-01-01

    Grafting of acrylic acid on polytetrafluoroethylene has been performed using films of the polymer gamma-irradiated in air and then treated with aqueous acrylic acid. It is concluded that the initiating centres are peroxides POOP', where P' is a small perfluorinated fragment, and also trapped peroxy radicals PO 2 radical which undergo deoxygenation. Homopolymerization is suppressed by polymerization inhibitors. (author)

  12. Managing latex allergies at home

    Science.gov (United States)

    ... Associate Clinical Professor of Medicine, Division of Allergy, Immunology, and Rheumatology, Georgetown University Medical School, Washington, DC. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Related MedlinePlus Health Topics Latex Allergy Browse the Encyclopedia A.D.A. ...

  13. 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.

  14. 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

  15. The Natural History of Kidney Graft Cortical Microcirculation Determined by Real-Time Contrast-Enhanced Sonography (RT-CES).

    Science.gov (United States)

    Jiménez, Carlos; López, María Ovidia; Ros, Amaia; Aguilar, Ana; Menendez, David; Rivas, Begoña; Santana, María José; Vaca, Marco Antonio; Escuin, Fernando; Madero, Rosario; Selgas, Rafael

    2016-01-01

    Kidney transplantation is the therapy of choice for end-stage kidney disease. Graft's life span is shorter than expected due in part to the delayed diagnosis of various complications, specifically those related to silent progression. It is recognized that serum creatinine levels and proteinuria are poor markers of mild kidney lesions, which results in delayed clinical information. There are many investigation looking for early markers of graft damage. Decreasing kidney graft cortical microcirculation has been related to poor prognosis in kidney transplantation. Cortical capillary blood flow (CCBF) can be measured by real-time contrast-enhanced sonography (RT-CES). Our aim was to describe the natural history of CCBF over time under diverse conditions of kidney transplantation, to explore the influence of donor conditions and recipient events, and to determine the capacity of CCBF for predicting renal function in medium term. RT-CES was performed in 79 consecutive kidney transplant recipients during the first year under regular clinical practice. Cortical capillary blood flow was measured. Clinical variables were analyzed. The influence of CCBF has been determined by univariate and multivariate analysis using mixed regression models based on sequential measurements for each patient over time. We used a first-order autoregression model as the structure of the covariation between measures. The post-hoc comparisons were considered using the Bonferroni correction. The CCBF values varied significantly over the study periods and were significantly lower at 48 h and day 7. Brain-death donor age and CCBF levels showed an inverse relationship (r: -0.62, p<0.001). Living donors showed higher mean CCBF levels than brain-death donors at each point in the study. These significant differences persisted at month 12 (54.5 ± 28.2 vs 33.7 ± 30 dB/sec, living vs brain-death donor, respectively, p = 0.004) despite similar serum creatinine levels (1.5 ± 0.3 and 1.5 ± 0.5 mg/dL). A

  16. Expression of VEGF and collagen using a latex biomembrane as bladder replacement in rabbits

    Directory of Open Access Journals (Sweden)

    André Luís Alonso Domingos

    2012-08-01

    Full Text Available OBJECTIVE: To investigate the VEGF expression and collagen deposition using a latex biomembrane as bladder replacement in rabbits. MATERIALS AND METHODS: After partial cystectomy, a patch of a non-vulcanized latex biomembrane (2 x 2 cm was sewn to the bladder of rabbits with 5/0 monofilament polydioxanone sulfate sutures in a watertight manner. Groups of 5 animals were killed at 15, 45 and 90 days after surgery and the bladder was removed. Sections of 5µm were cut and stained with picrosirius-red in order to estimate the amount of extracellular matrix in the graft. To confirm the presence of VEGF in tissues, protein expression was determined by immunohistochemistry. RESULTS: No death, urinary leakage or graft extrusion occurred in any group. All bladders showed a spherical shape. A progressive reduction in the amount of collagen occurred in the graft area and was negatively and linearly correlated with time (p < 0.001. VEGF expression was higher in grafted areas when compared to controls at 15 and 45 days after surgery and decreased with time (p < 0.001. CONCLUSION: The latex biomembrane as a matrix for partial bladder replacement in rabbits promotes temporary collagen deposition and stimulates the angiogenic process.

  17. Pilot scale experiments on radiation vulcanization of NR latex

    Science.gov (United States)

    Ridwan, M.

    The potential of irradiated latex as raw material of commercial use is under testing on pilot plant scale in Indonesia which has 225 kCi Co-60 irradiation facility and can irradiate 1000 tonnes of centrifuged latex per annum. The facility was jointly designed by BATAN of Indonesia and JAERI of Japan and was jointly financed by UNDP/IAEA, Government of Japan and Government of Indonesia under UNDP/IAEA Regional Cooperative Agreement Project on Industrial Application of Isotopes and Radiation Technology. The facility is a water pool type and can accomodate 400 kCi Co-60. The Co-60 rack has two shapes, plate and cylindrical shapes. The plate shape source is used for natural rubber latex irradiation and the cylindrical one is used for other irradiation services. The vulcanization system consists of three major components : emulsification unit ( height : 650 mm, diameter 500 mm ), mixing unit ( height : 1900mm, diameter 1200 mm ) and vulcanization reactor ( height : 1800 mm, diameter 1300 mm ). The first two components are located outside shielded room while the third one-in irradiation room. The radiation vulcanization process is a much simpler energy saving process comparedto the conventional thermal process which has two vulcanization steps before and after dipping. The physical and mechanical properties of irradiated NR Latex are comparable to those of sulfur vulcanized, and depend on many factors such as irradiation dose, sensitizer content, dry rubber content and storage time.

  18. Pilot scale experiments on radiation vulcanization of NR latex

    International Nuclear Information System (INIS)

    Ridwan, M.

    1985-01-01

    The potential of irradiated latex as raw material of commercial use is under testing on pilot plant scale in Indonesia which has 225 kCi Co-60 irradiation facility and can irradiate 1000 tonnes of centrifuged latex per annum. The facility was jointly designed by BATAN of Indonesia and JAERI of Japan and was jointly financed by UNDP/IAEA, Government of Japan and Government of Indonesia under UNDP/IAEA Regional Cooperative Agreement Project on Industrial Application of Isotopes and Radiation Technology. The facility is a water pool type and can accommodate 400 kCi Co-60. The Co-60 rack has two shapes, plate and cylindrical shapes. The plate shape source is used for natural rubber latex irradiation and the cylindrical one is used for other irradiation services. The vulcanization system consists of three major components: emulsification unit, mixing unit and vulcanization reactor. The first two components are located outside shielded room while the third one in irradiation room. The radiation vulcanization process is a much simpler energy saving process compared to the conventional thermal process which has two vulcanization steps before and after dipping. The physical and mechanical properties of irradiated NR latex are comparable to those of sulfur vulcanized. (author)

  19. Use of low energy accelerator for the radiation vulcanization of natural rubber latex and nitrile rubber. The battle for the sustainability and poverty alleviation

    International Nuclear Information System (INIS)

    Chirinos, Hugo D.; Lugao, Ademar B.

    2001-01-01

    The origin of the Hevea braziliensis tree was the Amazonian basin. The rubber expansion at the end of 19th century brought prosperity and determined the borders of Amazonian countries. In spite of that, the Brazilian government has failed in establishing a successful policy for improving the NR production in the jungle. This battle has been a continuous defeat against the environment as it was not possible to control the fungus Microcyclos ulei in its natural environment. The defeat was catastrophic for the population of Amazon region as they were not able to shift to other sustainable activity. As a consequence of the tack of economical options, the population had to explore all available natural resources. It has been also catastrophic for the Amazonian environment. Nevertheless, rubber plantations were successfully introduced in areas were Hevea braziliensis was not native, mainly in the southeast of Brazil. And recently, it was also introduced near marginal areas of the humid forest in the Amazon due to the absence of the fungus Microcyclos ulei. Both, extraction of wild rubber and plantation have a key role in the maintenance of the forest health as the seringueiros not only have a sustainable activity but can also play a role as soldiers of the jungle. Actually, rubber activities are not only associated to the environment but also with poverty because the activities are labor intensive, so it needs cheap labor. The poverty is unfortunately spread out in rural areas of Brazil and in the peripheral areas of the big cities. Regarding environment and poverty the dilemma is critical in the Amazonian region and is the following: the forest should be maintained healthy and protected from devastating projects and at the same time needs of the inhabitants should be considered. (author)

  20. 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

  1. Skin graft

    Science.gov (United States)

    Skin transplant; Skin autografting; FTSG; STSG; Split thickness skin graft; Full thickness skin graft ... donor site. Most people who are having a skin graft have a split-thickness skin graft. This takes ...

  2. Synthesis, characterization and wound healing imitation of Fe3O4 magnetic nanoparticle grafted by natural products

    Science.gov (United States)

    Pala, Sravan Kumar

    This research focused on the study of the core-shelled magnetic nanomaterials derived from a colloidal chemistry. The goals are four-fold: (1) synthesis of Fe3O4MNMs using colloidal chemistry. The Fe 3O4 MNMs were then grafted with extracts derived from natural products, namely Olecraceavar italica (broccoli), Boletus edulis (mushroom)and Solanum lycopersicum (tomato);(2)characterization of natural products by chromatography and mass spectrometry;(3) characterization of MNMs to determine their crystallinity, morphological and elemental composition by the state-of-the-art instruments; and (4) biological evaluation using Gram-negative and Gram-positive bacteria. The approach provides advantages to precisely control the composition and homogeneity. The second advantage of the colloidal chemistry is its user friendliness and feasibility. Due to the nature of the natural products, the compatibility of MNM is anticipated to be enhanced.In this chapter, the nanomaterials will be discussed from four perspectives,§1.1 Nanotechnology (§1.1), §1.2 Synthesis of nanomaterials; §1.3 The natural product extract,; §1.4 Characterization of nanomaterials; and §1.5Biological application of nanomaterials.Fig. 1 summarized the overarching goals of this study.

  3. Latex allergy and occupational asthma in health care workers: adverse outcomes.

    OpenAIRE

    Amr, Sania; Bollinger, Mary E.

    2004-01-01

    The prevalence of natural rubber latex (NRL) allergy has been estimated to be 5-18% in health care workers, and latex exposure has been one of the leading causes of occupational asthma in the last several years. We present the cases of two nurses who developed sensitivity to NRL, both with dermatologic symptoms and respiratory symptoms that included asthma. They were referred to the University of Maryland for evaluation of their allergies, then for occupational and environmental consults. The...

  4. Investigation on dielectric relaxation of PMMA-grafted natural rubber incorporated with LiCF3SO3

    International Nuclear Information System (INIS)

    Yap, K.S.; Teo, L.P.; Sim, L.N.; Majid, S.R.; Arof, A.K.

    2012-01-01

    Natural rubber (NR) grafted with 30 wt% poly (methyl methacrylate) (PMMA) and designated as MG30 has been added with varying amounts of LiCF 3 SO 3 . X-ray diffraction (XRD) shows the samples to be amorphous. Fourier transform infrared (FTIR) spectroscopy indicates complexation between the cation of the salt and the oxygen atom of the C=O and -COO- groups of MG30. From electrochemical impedance spectroscopy (EIS), MG30 with 30 wt% LiCF 3 SO 3 salt exhibits the highest ambient conductivity of 1.69×10 -6 S cm -1 and lowest activation energy of 0.24 eV. The dielectric behavior has been analyzed using dielectric permittivity (ε′), dissipation factor (tan δ) and dielectric modulus (M ⁎ ) of the samples. The dielectric constant of pure MG30 has been estimated to be ∼1.86.

  5. Latex sensitisation in healthcare workers in Singapore.

    Science.gov (United States)

    Tang, M B Y; Leow, Y H; Ng, V; Koh, D; Goh, C L

    2005-06-01

    Epidemiological data on latex sensitisation among Asian healthcare workers is lacking. The aim of the study is to determine the rate of latex sensitisation in our healthcare workers. We recruited 313 healthcare workers, of which 46.6% were operating theatre staff and 53.4% were non-operating theatre staff. Seventy-one administrative staff served as controls. All participants answered a self-administered questionnaire relating to latex exposure and glove-related symptoms. Latex sensitisation was determined by skin prick testing to latex and latex-specific IgE detection. The prevalence of latex sensitisation among healthcare workers was 9.6%, with no difference between operating theatre and nonoperating theatre staff. Glove-related symptoms were reported in 13.7% of all healthcare workers, of which 22.9% were sensitised to latex. Only 26.7% of latex-sensitised healthcare workers had glove-related symptoms while the rest were asymptomatic. The most common symptoms were itch and hand eczema but the most important discriminating symptom was contact urticaria. Personal history of atopy was more common in sensitised healthcare workers (40.0%) compared to non-sensitised workers (31.8%). Only 1 out of 9 (11.2%) symptomatic latex-sensitised subjects had sought previous medical attention for the problem. Latex sensitisation among healthcare workers in Singapore should be considered a significant occupational health risk, as it is in the West. Increased screening and awareness of this problem is essential to identify those at risk.

  6. 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.

  7. Periotest values of implants placed in sockets augmented with calcium phosphosilicate putty graft: a comparative analysis against implants placed in naturally healed sockets.

    Science.gov (United States)

    Mahesh, Lanka; Narayan, Tv; Kostakis, Georgios; Shukla, Sagrika

    2014-03-01

    To measure implant stability using periotest values of implants placed in sockets augmented with calcium phospho-silicate putty (CPS Putty) as compared with implant stability in naturally healed sockets. Twenty two sockets were implanted with CPS Putty immediately after extraction. The sockets were re-entered after a healing period at 5 to 6 months (average 5.3 months) for implant placement. Periotest values were recorded during implant insertion to assess primary stability. These were compared with the Periotest values of 26 implants placed in 22 patients, with naturally healed sockets. Periotest values were significantly lower in the grafted group, indicating better implant stability in sites grafted with CPS putty. Implant stability seems to be significantly higher in sockets augmented using CPS putty when compared to nongrafted sites. This suggests that socket grafting with CPS putty may enhance the quality of available bone for implantation.

  8. Reação anafilática durante transplante renal intervivos em criança alérgica ao látex: relato de caso Reacción anafiláctica durante transplante renal intervivos en niño alérgico al látex: relato de caso Anaphylaxis during renal transplantation of live donor graft in a child with latex allergy: case report

    Directory of Open Access Journals (Sweden)

    Glória Maria Braga Potério

    2009-04-01

    OBJECTIVES: Latex allergy is becoming increasingly more frequent, affecting patients and health care professionals. The objective of this report was to present the case of a child with allergy to latex, who developed anaphylaxis during anesthesia for renal transplantation, and emphasize some of the multidisciplinary conducts used to decrease the risk of anaphylactic shock after graft reperfusion. CASE REPORT: A male child, 5 years and 10 months old, P3 by the ASA classification, with a history of allergy to latex diagnosed after contact with balloons and confirmed by Rast test specific for latex and Prick test, underwent renal transplantation of a live donor graft for end-stage renal disease secondary to urologic malformation. The protocols for patients with Latex Allergy adopted by the Anesthesiology and Nursing Departments of the Hospital das Clínicas da UNICAMP were observed to avoid exposure of the child to latex. They started the day before the surgery by cleaning the operating rooms and substituting of all medical-hospital products by latex-free material. The equipment and materials used during the procedure were latex-free according to a technical report provided by the manufacturers. The surgery was done under general anesthesia and controlled mechanical ventilation. At the end of the surgery, the patient required blood transfusion, which was administered by a pressurizer; he developed cutaneous rash and the blood transfusion was discontinued, hydrocortisone was administered, and the infusion of crystalloids was increased. The child had an immediate and satisfactory response to the treatment. CONCLUSIONS: Latex allergy has become a public health problem and the knowledge of specific therapeutic conducts allows immediate treatment and decreases patient risks.

  9. Decontamination of latex gloves; Decontamination de gants en latex

    Energy Technology Data Exchange (ETDEWEB)

    Boutot, P; Schipfer, P; Blachere, A [Commissariat a l' Energie Atomique, Chusclan (France). Centre de Production de Plutonium de Marcoule

    1969-07-01

    Initially the latex gloves used in controlled zones were processed after use as radioactive waste. In view of the continually increasing number used, however, the persons in charge of the SPRAR have considered the possibility of decontaminating the gloves and using them again after control. The recovery installations which have been developed were initially designed rather crudely and operated irregularly; they have been progressively improved as a result of the experience acquired; today they are more really an industrial concern, equipped with automatic machinery. In 1967 it has been possible with this set-up to recover 247000 pairs of gloves, representing nearly 70 per cent of the number treated. (author) [French] Initialement, les gants de latex utilises dans les zones controlees etaient conditionnes apres emploi comme dechets radioactifs. Mais, devant l'augmentation sans cesse croissante des quantites employees, les responsables du SPRAR ont envisage leur decontamination et leur recyclage apres controles. Les installations de recuperation mises au point, de conception artisanale et fonctionnant de maniere episodique au depart, se sont progressivement ameliorees au fur et a mesure de l'experience acquise; elles revetent aujourd'hui le caractere d'une exploitation industrielle equipee de machines automatiques. En 1967, ces nouvelles installations ont permis de recuperer 247000 paires de gants, ce qui represente pres de 70 pour cent des quantites traitees. (auteur)

  10. Latex allergy: an emerging

    Directory of Open Access Journals (Sweden)

    Fernando Samuel Sion

    2013-11-01

    Full Text Available RESUMO: A alergia ao látex é manifestação de hipersensibilidade imediata mediada por IgE à proteína do látex natural, com variedade de sinais clínicos como urticária de contato, dermatite de contato por irritação primária ou por mecanismo de hipersensibilidade tardia, angioedema, asma, até anafilaxia. Com maior risco para a alergia ao látex estão os trabalhadores da área de saúde e demais profissões que usam látex. Pacientes com hipersensibilidade ao látex podem apresentar reação cruzada a frutas / alimentos, especialmente banana, kiwi e abacate. O diagnóstico é feito por detecção de anticorpos IgE específicos, testes cutâneos de puntura e testes de contato. Prevenção à exposição, substituição e utilização de produtos livres de látex, como luvas sintéticas são essenciais para os afetados. Adaptações no local de trabalho devem ser feitas com uso de luvas sem talco, com baixo teor de alérgenos ou luvas sintéticas. Estas medidas preventivas reduziram significativamente a prevalência de reações. Descritores: Alergia ao látex, Alimentos e alergia ao látex, Prevenção a reação ao látex.

  11. EDITORIALS Latex allergy: 'Plight, rights and fights'

    African Journals Online (AJOL)

    anaphylaxis and life-threatening food allergies to cross-reacting fruit allergens such as kiwi, banana, tomato and chestnuts). Latex allergy is also encountered more frequently in children with spina bifida than in other hospitalised children.[7] Sensitisation is usually confirmed by commercial latex allergy skinprick testing or by ...

  12. 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.

  13. Nitrile versus Latex for Glove Juice Sampling.

    Science.gov (United States)

    Landers, Timothy F; Dent, Anthony

    2014-01-01

    The objective of this study was to explore the utility of nitrile gloves as a replacement for latex surgical gloves in recovering bacteria from the hands. Two types of nitrile gloves were compared to latex gloves using the parallel streak method. Streaks of Klebsiella pneumoniae and Staphylococcus aureus were made on tryptic soy agar plates, and the zones of inhibition were measured around pieces of glove material placed on the plates. Latex gloves produced a mean zone of inhibition of 0.28 mm, compared to 0.002 mm for nitrile gloves (pnitrile may be a viable alternative to latex in glove juice sampling methods, since nitrile avoids the risk of latex exposure.

  14. Nitrile versus Latex for Glove Juice Sampling.

    Directory of Open Access Journals (Sweden)

    Timothy F Landers

    Full Text Available The objective of this study was to explore the utility of nitrile gloves as a replacement for latex surgical gloves in recovering bacteria from the hands. Two types of nitrile gloves were compared to latex gloves using the parallel streak method. Streaks of Klebsiella pneumoniae and Staphylococcus aureus were made on tryptic soy agar plates, and the zones of inhibition were measured around pieces of glove material placed on the plates. Latex gloves produced a mean zone of inhibition of 0.28 mm, compared to 0.002 mm for nitrile gloves (p<.001. While the parallel streak method is not intended as a quantitative estimate of antimicrobial properties, these results suggest that nitrile may be a viable alternative to latex in glove juice sampling methods, since nitrile avoids the risk of latex exposure.

  15. Histologic Evaluation of Critical Size Defect Healing With Natural and Synthetic Bone Grafts in the Pigeon ( Columba livia ) Ulna.

    Science.gov (United States)

    Tunio, Ahmed; Jalila, Abu; Goh, Yong Meng; Shameha-Intan; Shanthi, Ganabadi

    2015-06-01

    Fracture and bone segment loss are major clinical problems in birds. Achieving bone formation and clinical union in a fracture case is important for the survival of the bird. To evaluate the efficacy of bone grafts for defect healing in birds, 2 different bone grafts were investigated in the healing of a bone defect in 24 healthy pigeons ( Columba livia ). In each bird, a 1-cm critical size defect (CSD) was created in the left ulna, and the fracture was stabilized with external skeletal fixation (ESF). A graft of hydroxyapatite (HA) alone (n = 12 birds) or demineralized bone matrix (DBM) combined with HA (n = 12 birds) was implanted in the CSD. The CSD healing was evaluated at 3 endpoints: 3, 6, and 12 weeks after surgery. Four birds were euthanatized at each endpoint from each treatment group, and bone graft healing in the ulna CSD was evaluated by histologic examination. The CSD and graft implants were evaluated for quality of union, cortex development, and bone graft incorporation. Results showed no graft rejection in any bird, and all birds had connective tissue formation in the defect because of the bone graft application. These results suggest that bone defect healing can be achieved by a combination of osteoinductive and osteoconductive bone graft materials for clinical union and new bone regeneration in birds. The combination of DBM and HA resulted in a better quality bone graft (P < .05) than did HA alone, but there was no significant differences in cortex development or bone graft incorporation at 3, 6, or 12 weeks. From the results of this study, we conclude that HA bone grafts, alone or in combination with DBM, with external skeletal fixation is suitable and safe for bone defect and fracture treatment in pigeons.

  16. Status RVNRL in German latex industry and its introduction to the European market

    International Nuclear Information System (INIS)

    Bez, W.

    1996-01-01

    Reasons to look for an alternative crosslinking system avoiding sulphur curing was the restrictive policy of the German Health Authorities concerning nitrosamines. It was concluded that radiation curing offers further advantages . By avoiding the accelerators, type IV allergy is excluded, cytotoxicity is minimised to a very low level, films have better clarity and when thoroughly leached higher electrical resistance. Treatment of waste give no SO sub 2 emissions by burning, no Zinc in the ashes and possibly better microbial degradation. A development was carried out to irradiate natural latex by electron beam with a Dynamitron equipment. It was found trimethylolpropanetrimethacrylate to be a suitable sensitizer. Because of to high prices this development was interrupted. For future application trials and efforts to introduce RVNRL in the market gamma ray radiated natural latex either from Batan, Indonesia or MINT, Malaysia are used. Mainly dipped goods were produce, but radiated natural latex has shown good results in other processes. During discussions with customers it has proved necessary to establish specifications for RVNRL. A serious problem using natural latex for the production of medical devices is the type I allergy. Attempts are made to dip surgical gloves, leach them thoroughly and control extractable proteins were reduced to the very low level of 6.5 μg/g. Out of 18 patients sensitive to natural latex protein wearing gloves made from RVNRL only six have shown a positive response. That means RVNRL could help to solve the protein allergy problem. Further developments on this line are scheduled

  17. Synthesis and properties of silane-fluoroacrylate grafted starch.

    Science.gov (United States)

    Qu, Jia; He, Ling

    2013-10-15

    The latex of silane-fluoroacrylate grafted starch for coating materials, VTMS-starch/P(MMA/BA/3FMA), is obtained by two step grafting reactions. Vinyltrimethoxysilane (VTMS) is primarily grafted onto starch by condensation between Si-OH and C-OH at 120 °C, and then the copolymer of methyl methacrylate (MMA), butyl acrylate (BA) and 2,2,2-trifluoroethyl methacrylate (3FMA) is grafted onto the VTMS-starch by emulsion polymerization. Fourier transform infrared spectrometry (FTIR) and X-ray photoelectron spectroscopy (XPS) have been used to confirm the chemically grafting reactions in every step. The conversion percent, grafting percent and grafting efficiency for VTMS-starch/p(MMA/BA/3FMA) latex indicate that the optimum conditions should be controlled at 75 °C for 1h as VTMS-starch/P(MMA/BA/3FMA) in 1/3 weight ratio. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis have revealed that the latexes exhibit the uniform spherical particles of 40-60 nm in a narrow size distribution. The latex films perform the obvious hydrophobic (107°) property, lower surface free energy (25-35 mN/m) and the higher thermostability (330-440 °C) than starch (51°, 51.32 mN/m, 100-330 °C). Dynamic thermomechanical analysis (DMA) shows that the latex film could gain considerable toughness and strength with an elongation at break of 39.45% and a tensile strength of 11.97 MPa. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Preparation of composites of national rubber latex (NRL) - portland cement mould. Vol. 3

    International Nuclear Information System (INIS)

    Dessouki, A.M.; Taher, N.H.; El-Nahas, H.H.

    1996-01-01

    The aim of this study is to prepare some polymeric mould using national rubber latex (NRL) - portland cement composites based on a delayed- action mechanism. Factors affecting the preparation process such as concentration, mixing percentage, additives and their effect on what is regarded as a delayed action coacervant combination was studied. Composites of national latex (NRL) - portland cement would were prepared as two separate parts. The stabilized natural rubber latex (NRL) 100 parts with hydroxy ethyl cellulose (HEC) 2 parts as stabilizer and a delayed - action coacervant (sodium meta silicate as a delaying agent) 5 parts on one hand and the dry blend of cement 65 parts soluble in 65 parts of water as a paste on the other hand were mixed thoroughly on site. (HEC) was added to the rubber latex to prevent the coagulation of the rubber latex with the electrolyte (sodium meta silicate) present in the rubber mixture. Two kinds of stabilization occurred in the rubber part, namely steric stabilization and the stabilization against electrolyte. The effect of delayed - action coacervant (sodium meta silicate) on the initial setting time of rubber - cement mould showed that the molding process did not occur at sodium meta silicate concentration less than 2.66 parts per 100 parts of rubber latex (phr), and the optimum concentration used was 5% parts of rubber latex. It was observed that addition of a delaying agent (Sodium meta silicate) to the rubber part enhanced the delaying mechanism in the time needed for the molding process, while the addition of the delaying agent to the cement part did not have any effect on retardation of the molding process. Chemical coacervants function mainly by reducing the ζ potential which is associated with the electrical double layer surrounding the latex particle. This reduction may brought about in at least three distinct ways which take place in the system studied. 5 figs., 3 tabs

  19. Preparation of composites of national rubber latex (NRL) - portland cement mould. Vol. 3

    Energy Technology Data Exchange (ETDEWEB)

    Dessouki, A M; Taher, N H; El-Nahas, H H [National Center for Radiation Research and Technology, Atomic Energy Athority, Cairo (Egypt)

    1996-03-01

    The aim of this study is to prepare some polymeric mould using national rubber latex (NRL) - portland cement composites based on a delayed- action mechanism. Factors affecting the preparation process such as concentration, mixing percentage, additives and their effect on what is regarded as a delayed action coacervant combination was studied. Composites of national latex (NRL) - portland cement would were prepared as two separate parts. The stabilized natural rubber latex (NRL) 100 parts with hydroxy ethyl cellulose (HEC) 2 parts as stabilizer and a delayed - action coacervant (sodium meta silicate as a delaying agent) 5 parts on one hand and the dry blend of cement 65 parts soluble in 65 parts of water as a paste on the other hand were mixed thoroughly on site. (HEC) was added to the rubber latex to prevent the coagulation of the rubber latex with the electrolyte (sodium meta silicate) present in the rubber mixture. Two kinds of stabilization occurred in the rubber part, namely steric stabilization and the stabilization against electrolyte. The effect of delayed - action coacervant (sodium meta silicate) on the initial setting time of rubber - cement mould showed that the molding process did not occur at sodium meta silicate concentration less than 2.66 parts per 100 parts of rubber latex (phr), and the optimum concentration used was 5% parts of rubber latex. It was observed that addition of a delaying agent (Sodium meta silicate) to the rubber part enhanced the delaying mechanism in the time needed for the molding process, while the addition of the delaying agent to the cement part did not have any effect on retardation of the molding process. Chemical coacervants function mainly by reducing the {zeta} potential which is associated with the electrical double layer surrounding the latex particle. This reduction may brought about in at least three distinct ways which take place in the system studied. 5 figs., 3 tabs.

  20. [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.

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

    International Nuclear Information System (INIS)

    Martins, Carlos Felipe Pinto

    2005-01-01

    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 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)

  2. Morphological Study on Room-Temperature-Cured PMMA-Grafted Natural Rubber-Toughened Epoxy/Layered Silicate Nanocomposite

    Directory of Open Access Journals (Sweden)

    N. Y. Yuhana

    2012-01-01

    Full Text Available A morphological study was conducted on ternary systems containing epoxy, PMMA-grafted natural rubber, and organic chemically modified montmorillonite (Cloisite 30B. Optical microscopy, transmission electron microscopy (TEM, scanning electron microscopy (SEM, energy dispersive X-ray (EDX, and wide-angle X-ray diffraction (WAXD analysis were used. The following four materials were prepared at room temperature: cured unmodified epoxy, cured toughened epoxy, cured unmodified epoxy/Cloisite 30B nanocomposites, and cured toughened epoxy/Cloisite 30B nanocomposites. Mixing process was performed by mechanical stirring. Poly(etheramine was used as the curing agent. The detailed TEM images revealed co-continuous and dispersed spherical rubber in the epoxy-rubber blend, suggesting a new proposed mechanism of phase separation. High-magnification TEM analysis showed good interactions between rubber and Cloisite 30B in the ternary system. Also, it was found that rubber particles could enhance the separation of silicates layers. Both XRD and TEM analyses confirmed that the intercalation of Cloisite 30B was achieved. No distinct exfoliated silicates were observed by TEM. Aggregates of layered silicates (tactoids were observed by SEM and EDX, in addition to TEM at low magnification. EDX analysis confirmed the presence of organic and inorganic elements in the binary and ternary epoxy systems containing Cloisite 30B.

  3. Carboxymethyl Cellulose From Kenaf Reinforced Composite Polymer Electrolytes Based 49 % Poly (Methyl Methacrylate)-Grafted Natural Rubber

    International Nuclear Information System (INIS)

    Serawati Jafirin; Ishak Ahmad; Azizan Ahmad; Ishak Ahmad; Azizan Ahmad

    2014-01-01

    Composite polymer electrolytes based 49 % poly(methyl methacrylate)-grafted natural rubber (MG49) incorporating lithium triflate (LiCF 3 SO 3 ) were prepared. The study mainly focuses on the ionic conductivity performances and mechanical properties. Prior to that, carboxymethyl cellulose was synthesized from kenaf fiber. The films were characterized by electrochemical impedance (EIS) spectroscopy, linear sweep voltammetry (LSV), universal testing machine and scanning electron microscopy (SEM). The conductivity was found to increase with carboxymethyl cellulose loading. The highest conductivity value achieved was 6.5 x 10 -6 Scm -1 upon addition of 6 wt % carboxymethyl cellulose. LSV graph shows the stability of this film was extended to 2.7 V at room temperature. The composition with 6 wt % carboxymethyl cellulose composition showed the highest tensile strength value of 7.9 MPa and 273 MPa of Young's modulus. The morphology of the electrolytes showed a smooth surface of films after addition of salt and filler indicating amorphous phase in electrolytes system. Excellent mechanical properties and good ionic conductivity are obtained, enlightening that the film is suitable for future applications as thin solid polymer electrolytes in lithium batteries. (author)

  4. 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%.

  5. Identification and characterization of Euphorbia nivulia latex proteins.

    Science.gov (United States)

    Badgujar, Shamkant B; Mahajan, Raghunath T

    2014-03-01

    The protein profile of latex of Euphorbia nivulia Buch.-Ham. is established. Three new proteins viz., Nivulian-I, II and III have been purified to homogeneity from the latex. The relative molecular masses of Nivulian-I, II and III are 31,486.985, 43,670.846 and 52,803.470 Da respectively. Nivulian-I is a simple type of protein while Nivulian-II and III are glycoproteins. Peptide mass fingerprint analysis revealed peptides of these proteins match with Tubulin alpha-1 chain of Eleusine indica, Maturase K of Banksia quercifolia and hypothetical protein of Zea mays respectively. Tryptic digestion profile of Nivulian-I, II and III, infer the exclusive nature of latex origin proteins and may be new and are additive molecules in the dictionaries of phytoproteins or botany. This is the first of its kind, regarding characterization and validation of Nivulian-I, II and III with respect to peptide sequencing. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. The entry of free radicals into polystyrene latex particles

    International Nuclear Information System (INIS)

    Adams, M.E.; Trau, M.; Gilbert, R.C.; Napper, D.R.

    1988-01-01

    Mechanistic understanding of the processes governing the kinetics of emulsion polymerization has both scientific and technical interest. One component of this process that is poorly understood at present is that of free radical entry into latex particles. Measurements were made of the entry rate coefficient as a function of temperature for free radicals entering polystyrene latex particles in seeded emulsion polymerizations initiated by γ-rays. The activation energy for entry was found to be less than 24 ± 3 kJ mol -1 , consistent with entry being controlled by a physical (e.g. diffusional) rather than a chemical process. Measurement of the entry rate coefficient as a function of the γ-ray dose rate suggested that the factors that determine the entry rate when the primary free radicals are uncharged are similar to those that determine the entry rate for charged free radicals derived from chemical initiation by peroxydisulfate. This result was consistent with measurements of the entry rate coefficient of charged free radicals derived from peroxydisulfate; these data were found to be virtually independent of both the extent of the latex surface coverage by the anionic surfactant sodium dodecyl sulfate and the ionic strength of the continuous phase. The data refute several proposals given in the literature for the rate-determining step for entry, being inconsistent with control by collision of free radicals with the latex particles, surfactant desorption, and an electrostatic barrier arising from the colloidal nature of the entering free radical. The origin of the activation energy for entry remains obscure

  7. Allergy to latex in health workers

    Directory of Open Access Journals (Sweden)

    Fajardo-Zapata, Álvaro L.

    2015-01-01

    Full Text Available Introduction: A common and growing problem in hospitals is hypersensitivity to rubber latex antigens, since many products, including gloves, are manufactured from this material, with the consequent possibility of producing allergy in persons who use them. Objective: To find out if health workers at a fourth level clinic in Bogotá, Colombia, are allergic to rubber latex, in relation to the use of gloves. Materials and methods: Descriptive, cross-sectional study of a non-probabilistic intentional-type sample in each one of four hospital units. A survey was applied to participants. Results: 16 of the 26 persons (61.5% with history of allergic processes manifested some kind of reaction when they had contact with latex gloves; the problem was more significant in the nursing personnel compared to physicians. Conclusions: The exposure to latex gloves may be generating the appearance of allergic occupational disease in health workers.

  8. 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. .... Occupation. No of .... latex protein residue and act as a hapten or .... at Work Act, 1989 and the safety, Health and Welfare at.

  9. An evidence-based approach to medication preparation for the surgical patient at risk for latex allergy: is it time to stop being stopper poppers?

    Science.gov (United States)

    Heitz, James W; Bader, Stephen O

    2010-09-01

    The prevalence of latex allergy is increasing in surgical patient populations. Avoidance of exposure to the allergen is essential to minimizing perioperative complications in patients suspected to be at risk. Natural rubber latex has historically been ubiquitous in medical devices containing rubber. In 1998, the Food and Drug Administration (FDA) began to require the labeling of medical devices made from natural rubber latex; since that time substantial progress has been made in identifying latex-free alternatives. However, the rubber stoppers commonly found in pharmaceutical vial closures are exempt from FDA labeling requirements. Examination of the clinical and basic science literature regarding pharmaceutical vial closures supports limiting the rubber stopper to a single needle puncture as a safer practice, with the caveat that no strategy exists for the complete elimination of risk as long as stoppers made from natural rubber latex are used in pharmaceutical vials intended for human use. Copyright © 2010 Elsevier Inc. All rights reserved.

  10. [Prevention of adverse effects in latex allergic patients: organizing a latex safe operating theatre].

    Science.gov (United States)

    Bonalumi, Sabrina; Barbonaglia, Patrizia; Bertocchi, Carmen

    2006-01-01

    In 2001 the General Health Direction of Region Lombardia approved (decree n. 22303) a guideline for the prevention of latex allergic reactions in patients and health care workers. This document provides general recommendations in order to standardize behaviors in regional health care facilities. The reason is due to a rise in the incident of reactions to latex products in the last 20 years. Nowadays the prevalence is higher in certain risk groups (subjected to frequent and repeated exposures) rather than the general population. The aim of the project was to organize a latex safe operating theatre in the Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena of Milan (Fondazione) and to standardize behaviors in order to prevent adverse effects in latex allergic patients. Thanks to the literature review and the creation of a multidisciplinar team, we produced a protocol. Therefore, we requested manufacturers the certification of the latex content of their products. Results and conclusion. When latex allergic patients need to undergone surgery in our hospital, a latex safe operating theatre is organized by personnel following a multidisciplinar protocol. No allergic reactions were experienced during surgical procedures after the creation of an environment as free as possible from latex contamination. The project will involve an emergency room, one room or more of a ward and of the outpatients department.

  11. Performance Study of the Natural Rubber Composite with Clay Minerals

    International Nuclear Information System (INIS)

    Nyo Nyo Myint; Tin Tin Aye; Kyaw Myo Naing; Nyunt Wynn

    2008-03-01

    The preparation, characterization and some applications of natural rubber clay composite have been studied. This study investigated the possibility of natural rubber latex to replace some part of natural clays. In formulation of rubber clay composite from natural rubber latex and various clay minerals, three main steps were involved (i) preparation of latex cream (ii) prevulcanization of latex cream (iii) mixing vulcanized latex compound, with other ingredients. In each step, several parameters have been carefully investigated to optimize the performance of natural rubber clay composite production. The composite products were of better quality and can be considered to be more cost effective.

  12. Latex allergy: new insights to explain different sensitization profiles in different risk groups.

    Science.gov (United States)

    Peixinho, C; Tavares-Ratado, P; Tomás, M R; Taborda-Barata, L; Tomaz, C T

    2008-07-01

    Differences in latex allergen sensitization profiles have been described between children subjected to repetitive surgical interventions and health care workers (HCW). 'Major' allergens for patients with spina bifida are Hev b 1, 3 and 7, while for HCW, 'major' allergens are Hev b 2, 5, 6.01 and 13. The reason for these differential sensitization profiles is currently unknown. To investigate latex allergen profiles on internal and external surfaces of natural rubber latex gloves. Eighty-two samples of commonly used surgical gloves (41 glove brands) were used for analysis. Specific allergen levels of Hev b 1, 3, 5 and 6.02 on both surfaces of the gloves were quantified using an enzyme immunometric assay, a FITkit (FIT Biotech, Tampere, Finland). Differences in allergen levels were observed between internal and external surfaces of all glove types. Concentrations of Hev b 1 and Hev b 3 were significantly higher on external surfaces, while internal surfaces had higher allergen levels of Hev b 5 and Hev b 6.02. Analysis of surgical and examination gloves, powdered and nonpowdered gloves also showed that the content of Hev b 5 and Hev b 6.02 was significantly higher on internal surfaces while that of Hev b 1 and Hev b 3 was higher on external surfaces. Our study showed different allergen profiles on internal and external surfaces of natural rubber latex gloves. These results may suggest a relationship between latex allergen localization and sensitization routes in different risk groups.

  13. Rubber/clay nanocomposites by combined latex compounding and melt mixing: A masterbatch process

    International Nuclear Information System (INIS)

    Tan, Jinghua; Wang, Xiaoping; Luo, Yuanfang; Jia, Demin

    2012-01-01

    Highlights: → Rubber/Ca-montmorillonite nanocomposites were prepared by the masterbatch process. → Latex compounding method is efficient to improve the Ca-montmorillonite dispersion. → Exfoliated structure was obtained in the masterbatch by latex compounding method. → Intercalated and exfoliated structures were achieved in the vulcanizate. → The properties of vulcanizate are improved by the addition of Ca-montmorillonite. -- Abstract: Rubber/Ca-montmorillonite (Ca-MMT) nanocomposites with well exfoliated Ca-MMT layers were prepared by combination of latex compounding and melt mixing. Firstly, a high Ca-MMT content masterbatch was co-coagulated by natural rubber (NR) latex and modified Ca-MMT aqueous suspension through latex compounding. The masterbatch was added in the system of styrene butadiene rubber (SBR) and epoxidized natural rubber (ENR) by melt mixing subsequently. The X-ray diffraction (XRD) and transmission electronic microscopy (TEM) results showed that intercalated and exfoliated nanocomposites were obtained by the masterbatch technique. The effects of modified Ca-MMT introduction into the rubber matrix, via the masterbatch technique, on the properties of the resulting composites were studied. It was found that the vulcanization was hindered by the incorporation of modified Ca-MMT, while mechanical performances, thermal stability and aging resistance were improved. The increasingly glass transition temperature and the storage modulus with the loading of modified Ca-MMT were measured by dynamic mechanical analysis (DMA).

  14. Anti-ulcer activity of Synadenium grantii latex

    Directory of Open Access Journals (Sweden)

    Larissa L. G. Costa

    2012-10-01

    Full Text Available Synadenium grantii Hook f., Euphorbiaceae, is popularly known as leitosinha or janaúba. The diluted latex (18 drops/L of water is commonly used in the south of Brazil to treat gastric disturbances. This study evaluated phytochemical screening and toxicity using Artemia salina Leach of crude bark extract and also latex. The toxicity and the anti-ulcer activity of S. grantii latex were also tested in rats. Phytochemical results showed presence of tannins, terpenes, unsaponificable substances, coumarins and anthraquinones in the crude bark extract and terpenes in the latex. Gas chromatography-mass spectrometry (GC-MS analysis demonstrated the presence of diterpene tigliane esters in the latex, identified as 12-deoxyphorbol-13-(2-metilpropionate and phorbol 12,13,20-triacetate. The toxicity results using A. salina presented CL50 26.58μg/mL and CL50 778.66μg/mL, for the latex and the crude bark extract respectively. The toxicological hepatic parameters of the diluted latex were not different to the control group (p<0.05. The eosinophils cells showed an increase in both the diluted and pure latex groups. The pure latex showed gastric protection of 90% (p<0.05 and the diluted latex showed 6% compared to the negative control. Therefore, our data indicate that S. grantii latex, under research conditions presented gastric protection. Pure latex showed more toxicity than the diluted latex.

  15. Recombinant albumin monolayers on latex particles.

    Science.gov (United States)

    Sofińska, Kamila; Adamczyk, Zbigniew; Kujda, Marta; Nattich-Rak, Małgorzata

    2014-01-14

    The adsorption of recombinant human serum albumin (rHSA) on negatively charged polystyrene latex micro-particles was studied at pH 3.5 and the NaCl concentration range of 10(-3) to 0.15 M. The electrophoretic mobility of latex monotonically increased with the albumin concentration in the suspension. The coverage of adsorbed albumin was quantitatively determined using the depletion method, where the residual protein concentration was determined by electrokinetic measurements and AFM imaging. It was shown that albumin adsorption was irreversible. Its maximum coverage on latex varied between 0.7 mg m(-2) for 10(-3) M NaCl to 1.3 mg m(-2) for 0.15 M NaCl. The latter value matches the maximum coverage previously determined for human serum albumin on mica using the streaming potential method. The increase in the maximum coverage was interpreted in terms of reduced electrostatic repulsion among adsorbed molecules. These facts confirm that albumin adsorption at pH 3.5 is governed by electrostatic interactions and proceeds analogously to colloid particle deposition. The stability of albumin monolayers was measured in additional experiments where changes in the latex electrophoretic mobility and the concentration of free albumin in solutions were monitored over prolonged time periods. Based on these experimental data, a robust procedure of preparing albumin monolayers on latex particles of well-controlled coverage and molecule distribution was proposed.

  16. 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 molecules. Several models were examined, including the possible development of core-shell structures at lower molecular weights.

  17. Home Healthcare Workers: How to Prevent Latex Allergies

    Science.gov (United States)

    ... can help prevent allergic reactions for both home healthcare workers and their clients. LATEX EXPOSURE REACTIONS Three ... being used). • Inform your employer and your personal healthcare professionals that you have latex allergy. • Wear a ...

  18. Use of a latex biomembrane for bladder augmentation in a rabbit model: biocompatibility, clinical and histological outcomes

    Directory of Open Access Journals (Sweden)

    Andre L. A. Domingos

    2009-04-01

    Full Text Available PURPOSE: To investigate histological features and biocompatibility of a latex biomembrane for bladder augmentation using a rabbit model. MATERIAL AND METHODS: After a partial cystectomy, a patch of a non-vulcanized latex biomembrane (2x4 cm was sewn to the bladder with 5/0 monofilament polydioxanone sulfate in a watertight manner. Groups of 5 animals were sacrificed at 15, 45 and 90 days after surgery and the bladder was removed. The 5-µm preparations obtained from grafted area and normal bladder were stained with hematoxylin-eosin. Immunohistochemical staining was performed with a primary antibody against alpha-actin to assess muscle regeneration. RESULTS: No death, urinary leakage or graft extrusion occurred in any group. All bladders showed a spherical shape. Macroscopically, after 90 days, the latex biomembrane was not identifiable and the patch was indistinguishable from normal bladder. A bladder stone was found in one animal (6.6%. On the 90th day, histology revealed continuity of transitional epithelium of host bladder tissue on the patch area. At this time, the muscle layers were well organized in a similar fashion to native bladder muscle layers. The inflammatory process was higher on grafted areas when compared to controls: 15 days - p < 0.0001, 45 days - p < 0.001, and 90 days - p < 0.01. The anti alpha-actin immunoexpression peaked at 45 days, when the graft was observed covered by muscle cells. CONCLUSION: The latex biomembrane is biocompatible and can be used in models for bladder augmentation in rabbits. It promotes epithelium and muscle regeneration without urinary leakage.

  19. Angiogenic activity of Synadenium umbellatum Pax latex

    Directory of Open Access Journals (Sweden)

    PR. Melo-Reis

    Full Text Available Synadenium umbellatum Pax, popularly known as "cola-nota", is a medicinal plant that grows in tropical regions. Latex of this plant is used to treat various diseases such as diabetes mellitus, Hansen´s disease, tripanosomiases, leukemia and several malignant tumors. In the present study, the angiogenic activity of S. umbellatum latex was evaluated using the chick embryo chorioallantoic membrane (CAM assay. Results showed significant increase of the vascular net (p < 0.05 compared to the negative control (H2O. The histological analysis was in accordance with the results obtained. In conclusion, our data indicate that S. umbellatum latex, under the conditions of this research, presented angiogenic effect.

  20. Low field NMR study of the latex derived from Brosimum parinarioides - Moraceae

    International Nuclear Information System (INIS)

    Miguez, Eduardo; Tavares, Maria Ines B.

    2009-01-01

    Brosimum parinarioides is a tree found in the Amazonia forest and its latex (Leite de Amapa) is often used like food and by the popular medicine in the treatment of tuberculosis and asthma. Being swallowed in nature, its necessary determinate the stability degree of this latex in the storage conditions in which is used in Amazonia. The analyses of T 2 data showed that the limit of stability is not longer than six month in the storage conditions used by the population of Amazonia. The Low field NMR proved to be an efficient method for this kind of study. (author)

  1. 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...

  2. Plant latex lipase as biocatalysts for biodiesel production | Mazou ...

    African Journals Online (AJOL)

    Plant latex lipase as biocatalysts for biodiesel production. ... This paper provides an overview regarding the main aspects of latex, such as the reactions catalyzed, physiological functions, specificities, sources and their industrial applications. Keywords: Plant latex, lipase, Transesterification, purification, biodiesel ...

  3. Thermodynamics of swelling of latex particles with two monomers

    NARCIS (Netherlands)

    Maxwell, I.A.; Kurja, J.; van Doremaele, G.H.J.; German, A.L.

    1992-01-01

    The partitioning of 2 monomers between the latex particle, monomer droplet, and aq. phases of an emulsion polymer latex are measured at satn. swelling of the latex particle phase (corresponding to intervals I and II of an emulsion polymn.). The monomer (Me acrylate, Bu acrylate, styrene) and polymer

  4. 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.

  5. 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.

  6. 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.

  7. Industrial application of electron beams for grafting and vulcanization

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-12-31

    The topics discussed are radiation graft polymerization; industrial application of radiation grafting - ion exchange membrane for a battery separator, ammonia adsorbent, non-flammable PE (polyethylene) foam; R and D on radiation grafting, radiation vulcanization of natural rubber.

  8. Industrial application of electron beams for grafting and vulcanization

    International Nuclear Information System (INIS)

    Keizo Makuuchi

    1994-01-01

    The topics discussed are radiation graft polymerization; industrial application of radiation grafting - ion exchange membrane for a battery separator, ammonia adsorbent, non-flammable PE (polyethylene) foam; R and D on radiation grafting, radiation vulcanization of natural rubber

  9. 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)

  10. CHEMICAL EXAMINATION OF JACK TREE LATEX AND

    Indian Academy of Sciences (India)

    and on Saponification yielded fatty acids, Volatile as well as non-volatile. The unsaponifiable portion on repeated crystallisation provided a crystal- line, sharp melting compound which was identified as artostenone? from a. Latex (200 c.c.). ത്ത min- pe. Coagulum (A) Aqueous alcoholic solution (B). Acetone or ethyl acetate ...

  11. Bone grafting of alveolar socket and ovate seat pontic preparation for natural emergence profile for anterior bridge - A case report

    Directory of Open Access Journals (Sweden)

    Vijay Deshmukh

    2009-01-01

    Full Text Available Alveolar atrophy following tooth extraction remains a challenge for future prosthetic restorations. Immediate implant placement and postextraction alveolar bone grafting are two methods that are used to prevent significant postextraction bone loss. Grafting is one of the most common methods of socket preservation widely used to prevent the collapse of oral tissues following extraction so that an excellent esthetic prosthesis can be provided particularly in the anterior maxillary region. The present report describes the management of a maxillary tooth extraction socket using a socket preservation technique involving placement of an osteoconductive slowly resorbable grafting material & resorbable collagen membrane in the extraction socket also called as Bio-Col socket preservation technique followed by a provisional restoration to preserve the tissues & interdental papilla for the placement of future final ovate pontic anterior bridge to give the illusion of the tooth emerging from the gums. This technique resulted in a successful prevention of alveolar bone loss following tooth extraction & maintainence of tissue contour & density which provided a good tissue base for the fabrication of Ovate pontic giving excellent esthetic results.

  12. Triterpenoid biosynthesis in Euphorbia lathyris latex

    International Nuclear Information System (INIS)

    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 50 concentration of 3.2 μM. Fenpropimorph was found to have little or no effect on the biosynthesis. Tridemorph was found to inhibit the biosynthesis of all of the triterpenoids with an I 50 of 4 μM. It was also observed that the cyclopropyl containing triterpenols, cycloartenol and 24-methylenecycloartenol were inhibited much more strongly than those containing an 8-9 double bond, lanosterol and 24-methylenelanosterol. The evidence indicates, but does not definetely prove, that lanosterol and 24-methylenelanosterol are not made from cycloartenol and 24-methylenecycloartenol via a ring-opening enzyme such as cycloeucalenol-obtusifoliol isomerase. The possibilty that cycloartenol is made via lanosterol was investigated by synthesizing 4-R-4- 3 H-mevalonic acid and incubating latex with a mixture of this and 14 C-mevalonic acid. From the 3 H/ 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

  13. 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.

  14. Skin Graft

    OpenAIRE

    Shimizu, Ruka; Kishi, Kazuo

    2012-01-01

    Skin graft is one of the most indispensable techniques in plastic surgery and dermatology. Skin grafts are used in a variety of clinical situations, such as traumatic wounds, defects after oncologic resection, burn reconstruction, scar contracture release, congenital skin deficiencies, hair restoration, vitiligo, and nipple-areola reconstruction. Skin grafts are generally avoided in the management of more complex wounds. Conditions with deep spaces and exposed bones normally require the use o...

  15. A comparative study of natural, formaldehyde-treated and copolymer-grafted orange peel for Pb(II) adsorption under batch and continuous mode

    International Nuclear Information System (INIS)

    Lugo-Lugo, Violeta; Hernandez-Lopez, Susana; Barrera-Diaz, Carlos; Urena-Nunez, Fernando; Bilyeu, Bryan

    2009-01-01

    Natural, formaldehyde-treated and copolymer-grafted orange peels were evaluated as adsorbents to remove lead ions from aqueous solutions. The optimum pH for lead adsorption was found to be pH 5. The adsorption process was fast, reaching 99% of sorbent capacity in 10 min for the natural and treated biomasses and 20 min for the grafted material. The treated biomass showed the highest sorption rate and capacity in the batch experiments, with the results fitting well to a pseudo-first order rate equation. In the continuous test with the treated biomass, the capacity at complete exhaustion was 46.61 mg g -1 for an initial concentration of 150 mg L -1 . Scanning electronic microscopy and energy dispersive X-ray spectroscopy indicated that the materials had a rough surface, and that the adsorption of the metal took place on the surface. Fourier transform infrared spectroscopy revealed that the functional groups responsible for metallic biosorption were the -OH, -COOH and -NH 2 groups on the surface. Finally, the thermogravimetric analysis indicates that a mass reduction of 80% can be achieved at 600 deg. C

  16. Synthesis and characterization of novel fluoroalkyl-terminated hyperbranched polyurethane latex

    Science.gov (United States)

    Xu, Wei; Zhao, Weijia; Hao, Lifen; Wang, Sha; Pei, Mengmeng; Wang, Xuechuan

    2018-04-01

    Waterborne polyurethane (PU) emulsions are widely used in various fields and the demand for them is ever-increasing over the years. However, the hydrophilic chain extender inevitably bonded into the PU backbone can affect the water tolerance of PU. Thus, it is of great importance to improve PU water resistance effectively. Herein, novel fluoroalkyl-terminated hyperbranched polyurethane (HBPUF) latex was accordingly synthesized by graft reaction of perfluorohexyl ethyl alcohol and hyperbranched polyurethane (HBPU), which was previously obtained from interaction between hydroxyl-terminated hyperbranched polymer and PU prepolymer manufactured via the acetone process, as well as using neutralization, adding water, and high-speed stirring operations. We characterized the resultants and investigated its surface properties by IR, NMR, TEM, XRD, TGA, DSC, FE-SEM, AFM, XPS, and contact angle measurements, etc. IR and NMR tests confirmed that the fluorinated fragments had been grafted onto the tail end of HBPU. TEM, XRD, DSC, and FE-SEM results all accounted for the fact that there were multi-crystals in PU, HBPU and HBPUF. TGA results showed that thermal stabilities of the PU, HBPU, and HBPUF latex films were enhanced in turn. XPS and AFM analyses demonstrated that the fluorine-containing segments from the HBPUF terminals were prone to migrate and enrich on the film-air surface of the HBPUF latex film, which made water contact angle and water absorption of the HBPUF film be as 113.9° and 11.1%, respectively, compared to those of the PU film (77.8° and 136.2%). This research indicates that water resistance of the PU film can be efficiently enhanced by fluorinated polyurethane with novel fluoroalkyl-terminated hyperbranched structure.

  17. The effect of emulsifier on the stability of irradiated LA-TZ latex

    International Nuclear Information System (INIS)

    Made Sumarti K; Utama, Marga; Puspitasari, Tita

    1998-01-01

    The effect of six kinds of stabilizer on the stability of the concentrated LA-TZ latex which contains n-BA have been studied. The six stabilizers are: 1. Naphthalene sulfonic acid formaldehyde condensate, 2. Sodium dialkyl sulfosuccinate, 3. Triethanol amine lauryl sulfate, 4. Sodium polyoxyethylene alkyl phenol ether sulfate, 5. Dodecyl benzene sulfonic acid (Neopelex FS), and 6. Ammonium laurat. The concentrations of the stabilizers are in the range of 0,1 to 0,3% and of the n-BA is 5phr (per hundred rubber). The field natural rubber latex was stabilized by Tetramethyl tiuram disulfide - Zine oxide (TMTD-ZnO) and ammonium gas, and was concentrated by centrifuge. The obtain concentrated LA-TZ latex was added by the n-BA and was kept with various storage time i.e. o, 2, 4, 6, 18, and 24 hours. It was found that the stable latex was irradiated by 15 kGy dose and the physical properties was tested, then the maximum tensile strength of 223,3 kg/cm 2 was found on Neopelex FS concentrate at 0,1%. (authors)

  18. Latex allergy: assessment of knowledge, appropriate use of gloves and prevention practice among hospital healthcare workers.

    Science.gov (United States)

    Al-Niaimi, F; Chiang, Y Z; Chiang, Y N; Williams, J

    2013-01-01

    Healthcare workers and patients are often exposed to natural rubber latex (NRL) through contact with gloves and various healthcare products, which can potentially cause allergic reactions, with varying degrees of severity. In 2008, the Royal College of Physicians published their first evidence-based guidance on occupational health interventions for latex allergy, which emphasized the importance of healthcare workers having knowledge of latex allergy. This study aimed to survey the knowledge of healthcare workers (n = 156) about latex gloves and NRL allergy, routine prevention practice and the appropriate use of gloves in patient care. Healthcare workers in a large teaching hospital were surveyed using a standard questionnaire. We found that only 1% of healthcare workers were able to correctly match the appropriate gloves to the specifically designed procedure. More than half (n = 74.53%) were unable to recognize the presentation of type 1 allergy to NRL. Of the 156 participants, 131 (84%) considered that they would benefit from training about NRL allergy and the use of different types of gloves in clinical care. This survey indicates the importance of education regarding appropriate use of gloves and prevention of NRL allergy among healthcare workers, and dermatologists should play an important role in facilitating this. © The Author(s). CED © 2012 British Association of Dermatologists.

  19. Cement-latex grouting mortar for cementing boreholes

    Energy Technology Data Exchange (ETDEWEB)

    Kateev, I S; Golyshkina, L A; Gorbunova, I V; Kurochkin, B M; Vakula, Ya V

    1980-01-01

    The need for the development of cement-latex grouting mortar for the purpose of separating strata when reinforcing boreholes at deposits in the Tatar Associated SSR is evaluated. Results of studies of the physical and mechanical properties of cement-latex grouting mortar systems (mortar plus brick) are presented. Formulas for preparing cement-latex grouting mortor are evaluated and results of industrial tests of such mortars shown.

  20. Effect of Amphiphilic Alkyl Chain Length Upon Purified LATEX Stability

    International Nuclear Information System (INIS)

    Amira Amir Hassan; Amir Hashim Mohd Yatim

    2015-01-01

    Rubber particles in purified latex (PL) are stabilized by a film of protein and fatty acid soap (surfactant). Saturated straight-chain fatty acid soaps can assist an enhancement of latex stability. However, whether the alkyl chain length plays an important role in increasing the stability is still an issue. The aim of this study is to investigate the effect of alkyl chain length of anionic surfactant on the stability of purified latex. The fatty acid soap of decanoate (9), laurate (11), sodium dodecyl sulphate (SDS) (12) and palmitate (15) were used. The numbers in parentheses indicating the number of carbon present in alkyl chain of the soap. The results showed that the impact of alkyl chain length on the stability of latex is in the order of laurate > decanoate > SDS > palmitate > purified latex accordingly. The alkyl chain length does giving a significant effect on latex stability after longer stirring time. The particle size of latex with the presence of surfactant is greater compare to a single particle itself due to extension of particles diameter. Thus suitable interaction of the nonpolar tail of surfactant with the hydrophobic regions of latex surface played a major role in maintaining a stable latex system. (author)

  1. Pancreas grafts

    International Nuclear Information System (INIS)

    Hahn, D.; Buell, U.; Land, W.; Unertl, K.

    1981-01-01

    Perfusion studies with sup(99m)Tc-DTPA, which has hitherto been used routinely to investigate renal grafts, have also proved useful for monitoring the perfusion of pancreas grafts. A total perfusion failure is equally reliably demonstrable as in renal grafts. Quantitatively smaller perfusion alterations can be demonstrated by monitoring the course. It seems possible to differentiate the salivary edema of a rejection reaction, well known from animal experiments, with the help of other paramters (e.g. creatinine). Further clinical studies are however necessary to confirm these results. (orig.) [de

  2. Effects of Polyethylene Grafted Maleic Anhydride on the Mechanical, Morphological, and Swelling Properties of Poly (Vinyl Chloride / Epoxidized Natural Rubber / Kenaf Core Powder Composites

    Directory of Open Access Journals (Sweden)

    Rohani Abdul Majid

    2014-10-01

    Full Text Available The effects of polyethylene grafted maleic anhydride (PE-g-MA on the properties of poly (vinyl chloride/epoxidized natural rubber (PVC/ENR kenaf core powder composites were studied, with four different loadings of kenaf core powder (5, 10, 15, and 20 phr. The tensile properties indicated that the strength and elongation at break of the composites exhibited an increase for samples with PE-g-MA. Morphological analysis using a scanning electron microscope (SEM showed better dispersion of kenaf fiber with the addition of PE-g-MA and less kenaf powder agglomeration. Furthermore, the swelling index indicated that composites with PE-g-MA showed lower toluene absorption than composites without PE-g-MA.

  3. 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.

  4. [Latex allergy in a paediatric hospital. Characteristics and risk factors].

    Science.gov (United States)

    Bailey, Michael; Norambuena, Ximena; Roizen, Gigia; Rodríguez, Jorge; Quezada, Arnoldo

    The prevalence of latex sensitisation varies according to the population studied. There are various risk factors that increase latex sensitisation, such as genetic risk, atopy, and multiple surgeries. To characterise patients referred to an Immunology Unit with suspected latex allergy, and to analyse their clinical features and risk factors. A retrospective, descriptive study was conducted on children suspected of latex allergy. Their medical records were reviewed in order to assess symptoms with contact or exposure to latex materials. Known risk factors to latex sensitisation, such as pathologies requiring repeated surgery (spina bifida, myelomeningocele, scoliosis and nephro-urological alterations), atopy (rhinitis, asthma, atopic dermatitis) were investigated. A prick test and/or specific IgE to latex were also performed. A multivariate logistic regression model was performed to find associations between symptoms triggered by exposure to latex with underlying diseases and other risk conditions. A total of 106 patients were enrolled in the study, of whom 50 were evaluable. At diagnosis 96% of patients were older than five years. Most of the risk factors described were observable in these patients, such as multiple surgeries, neurological and nephro-urological malformations, surgery before one year-old, and repeated bladder catheterisation. After latex exposure, mucous cutaneous manifestations were the most common (52%), followed by respiratory symptoms (36%). All patients were sensitised and allergic to latex. Latex allergy is a significant problem in children with risk factors. The results shown in this study raise important challenges for preventive measures and awareness. Copyright © 2016 Sociedad Chilena de Pediatría. Publicado por Elsevier España, S.L.U. All rights reserved.

  5. 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 ...

  6. 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.

  7. 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

  8. 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

  9. 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.

  10. 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.

  11. Syntheses of crosslinked latex nanoparticles using differential microemulsion polymerization

    International Nuclear Information System (INIS)

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

    2013-01-01

    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. 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.

  13. The preparation of RVNRL using Malaysian-produced latexes

    International Nuclear Information System (INIS)

    Zin, W.M. bin W.; Mohid, N. bte; Hasan, J. bin; Noor, W.K.A. bte W.M.; Jaafar, Zulkifli

    1993-01-01

    This research project was carried out using latexes supplied by three of the suppliers in Malaysia. From the results of studies carried out in search of the best sensitiser for RVNRL preparation, the use of n-butyl acrylate (n-BA) as a sensitiser gave the most promising results. However, its use as a sensitiser is not universal to all latexes available in the country. The problem was overcome by using different formulations for different latexes. For the latex supplied by Golden Hope (Hytex), a combination of sensitisers i.e. n-BA plus 2-ethyl hexyl acrylate (2-EHA) with a 10% potassium hydroxide solution as the stabilizer, was required. Latex supplied by MARDEC (Matex), seemed to need only n-BA as the sensitiser. However, a stabilizer was still required and the use of a 10% KOH solution was found to be suitable. A large range of stabilizers and sensitisers were applicable to Guthrie latex. The use of n-BA as the sensitiser and potassium laurylic acid as the stabilizer seemed the most favourable formulation. All the results are discussed in the form of a correlation between dose and the tensile properties of RVNRL vulcanizates, equilibrium swelling ratio and standing time of the latex formulation. (author)

  14. 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.

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

    International Nuclear Information System (INIS)

    Inoue, Ken-ichiro; Takano, Hirohisa; Yanagisawa, Rie; Koike, Eiko; Shimada, Akinori

    2009-01-01

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

  16. Investigation on dielectric relaxation of PMMA-grafted natural rubber incorporated with LiCF{sub 3}SO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Yap, K.S.; Teo, L.P.; Sim, L.N.; Majid, S.R. [Centre for Ionics University of Malaya, Physics Department, University of Malaya, 50603 Kuala Lumpur (Malaysia); Arof, A.K., E-mail: akarof@um.edu.my [Centre for Ionics University of Malaya, Physics Department, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2012-07-01

    Natural rubber (NR) grafted with 30 wt% poly (methyl methacrylate) (PMMA) and designated as MG30 has been added with varying amounts of LiCF{sub 3}SO{sub 3}. X-ray diffraction (XRD) shows the samples to be amorphous. Fourier transform infrared (FTIR) spectroscopy indicates complexation between the cation of the salt and the oxygen atom of the C=O and -COO- groups of MG30. From electrochemical impedance spectroscopy (EIS), MG30 with 30 wt% LiCF{sub 3}SO{sub 3} salt exhibits the highest ambient conductivity of 1.69 Multiplication-Sign 10{sup -6} S cm{sup -1} and lowest activation energy of 0.24 eV. The dielectric behavior has been analyzed using dielectric permittivity ({epsilon} Prime), dissipation factor (tan {delta}) and dielectric modulus (M{sup Low-Asterisk }) of the samples. The dielectric constant of pure MG30 has been estimated to be {approx}1.86.

  17. Isolation and characterization of latex-specific promoters from Papaver somniferum L.

    OpenAIRE

    Raymond, Michelle Jean

    2004-01-01

    The pharmacologically important alkaloids morphine and codeine are found in latex of opium poppy (Papaver somniferum). Latex is harbored in laticifers, a specialized vascular cell-type. Isolation and characterization of latex-specific genes may provide a useful tool to metabolically engineer increased alkaloid production. Previous research in the Nessler laboratory identified genes that exhibit latex-specific gene expression. Latex-specific genes were an 2-oxoglutarate-dioxygense (DIOX), ...

  18. Thermoresponsive latexes for fragrance encapsulation and release.

    Science.gov (United States)

    Popadyuk, N; Popadyuk, A; Kohut, A; Voronov, A

    2016-04-01

    To synthesize cross-linked latex particles protecting the encapsulated fragrance at ambient temperatures and facilitating the release of cargo at the temperature of the surface of the skin that varies in different regions of the body between 33.5 and 36.9°C. Poly(stearyl acrylate) (PSA), a polymer with long crystallizable alkyl side chains (undergoes order-disorder transitions at 45°C), was chosen as the main component of the polymer particles. As a result, new thermoresponsive polymer particles for fragrance encapsulation were synthesized and characterized, including assessing the performance of particles in triggered release by elevated temperature. To obtain network domains of various crystallinity, stearyl acrylate was copolymerized with dipropylene glycol acrylate caprylate (DGAC) (comonomer) in the presence of a dipropylene glycol diacrylate sebacate (cross-linker) using the miniemulsion process. Comonomers and a cross-linker were mixed directly in a fragrance during polymerization. Fragrance release was evaluated at 25, 31, 35 and 39°C to demonstrate a new material potential in personal/health care skin-related applications. Particles protect the fragrance from evaporation at 25°C. The fragrance release rate gradually increases at 31, 35 and 39°C. Two slopes were found on release plots. The first slope corresponds to a rapid fragrance release. The second slope indicates a subsequent reduction in the release rate. Crystalline-to-amorphous transition of PSA triggers the release of fragrances from cross-linked latex particles at elevated temperatures. The presence of the encapsulated fragrance, as well as the inclusion of amorphous fragments in the polymer network, reduces the particle crystallinity and enhances the release. Release profiles can be tuned by temperature and controlled by the amount of loaded fragrance and the ratio of comonomers in the feed mixture. © 2015 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  19. Dragon Fruit Foliage Plant-Based Coagulant for Treatment of Concentrated Latex Effluent: Comparison of Treatment with Ferric Sulfate

    Directory of Open Access Journals (Sweden)

    Juferi Idris

    2013-01-01

    Full Text Available The effectiveness of dragon fruit foliage as a natural coagulant for treatment of concentrated latex effluent was investigated and compared with ferric sulfate, a chemical coagulant. Dragon fruit is a round and often red-colored fruit with scales-like texture and is native to south American countries which is also cultivated and heavily marketed in southeast Asian countries. Its foliage represents a part of its overall plant system. Latex effluent is one of the main byproduct from rubber processing factories in Malaysia. Three main parameters investigated were chemical oxygen demand (COD, suspended solids (SS, and turbidity of effluent. Coagulation experiments using jar test were performed with a flocculation system where the effects of latex effluent pH as well as coagulation dosage on coagulation effectiveness were examined. The highest recorded COD, SS, and turbidity removal percentages for foliage were observed for effluent pH 10 at 94.7, 88.9, and 99.7%, respectively. It is concluded that the foliage showed tremendous potential as a natural coagulant for water treatment purposes. The foliage could be used in the pretreatment stage of Malaysian latex effluent prior to secondary treatment.

  20. Cryo-SEM studies of latex/ceramic nanoparticle coating microstructure development.

    Science.gov (United States)

    Luo, Hui; Scriven, L E; Francis, Lorraine F

    2007-12-15

    Cryogenic scanning electron microscopy (cryo-SEM) was used to investigate microstructure development of composite coatings prepared from dispersions of antimony-doped tin oxide (ATO) nanoparticles (approximately 30 nm) or indium tin oxide (ITO) nanoparticles (approximately 40 nm) and latex particles (polydisperse, D(v): approximately 300 nm). Cryo-SEM images of ATO/latex dispersions as-frozen show small clusters of ATO and individual latex particles homogeneously distribute in a frozen water matrix. In contrast, cryo-SEM images of ITO/latex dispersions as-frozen show ITO particles adsorb onto latex particle surfaces. Electrostatic repulsion between negatively charged ATO and negatively charged latex particles stabilizes the ATO/latex dispersion, whereas in ITO/latex dispersion, positively charged ITO particles are attracted onto surfaces of negatively charged latex particles. These results are consistent with calculations of interaction potentials from past research. Cryo-SEM images of frozen and fractured coatings reveal that both ceramic nanoparticles and latex become more concentrated as drying proceeds; larger latex particles consolidate with ceramic nanoparticles in the interstitial spaces. With more drying, compaction flattens the latex-latex particle contacts and shrinks the voids between them. Thus, ceramic nanoparticles are forced to pack closely in the interstitial spaces, forming an interconnected network. Finally, latex particles partially coalesce at their flattened contacts, thereby yielding a coherent coating. The research reveals how nanoparticles segregate and interconnect among latex particles during drying.

  1. Stent graft placement for dysfunctional arteriovenous grafts

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Gyeong Sik [Dept. of Radiology, CHA Bundang Medical Center, College of Medicine, CHA University, Seongnam (Korea, Republic of); Shin, Byung Seok; Ohm, Joon Young; Ahn, Moon Sang [Chungnam National University Hospital, Daejeon (Korea, Republic of)

    2015-07-15

    This study aimed to evaluate the usefulness and outcomes of stent graft use in dysfunctional arteriovenous grafts. Eleven patients who underwent stent graft placement for a dysfunctional hemodialysis graft were included in this retrospective study. Expanded polytetrafluoroethylene covered stent grafts were placed at the venous anastomosis site in case of pseudoaneurysm, venous laceration, elastic recoil or residual restenosis despite the repeated angioplasty. The patency of the arteriovenous graft was evaluated using Kaplan-Meier analysis. Primary and secondary mean patency was 363 days and 741 days. Primary patency at 3, 6, and 12 months was 82%, 73%, and 32%, respectively. Secondary patency at the 3, 6, 12, 24, and 36 months was improved to 91%, 82%, 82%, 50%, and 25%, respectively. Fractures of the stent graft were observed in 2 patients, but had no effect on the patency. Stent graft placement in dysfunctional arteriovenous graft is useful and effective in prolonging graft patency.

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

    African Journals Online (AJOL)

    parameters and profitability of some rapid metabolic class clones of rubber ... of hormonal stimulation had no negative influence on the vegetative growth ..... yield (2597) was obtained with the control ..... metabolic energy of latex vessels as.

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

    African Journals Online (AJOL)

    Incidence of latex harvesting technologies on agronomic and physiological parameters and profitability of some rapid metabolic class clones of rubber tree ( Hevea brasiliensis ) in southwestern Côte d'Ivoire.

  4. The Synthesis and Modification of Nanosized Clickable Latex Particles

    KAUST Repository

    Almahdali, Sarah

    2013-01-01

    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

  5. PS-HEMA latex fractionation by sedimentation and colloidal crystallization

    Directory of Open Access Journals (Sweden)

    Cardoso André H.

    1999-01-01

    Full Text Available A poly(styrene-co-hydroxyethylmethacrylate latex underwent sedimentation under gravity followed by an spontaneous and extensive colloidal crystallization. It was then fractionated in three visually distinguishable layers. Latex aliquots layers were sampled at different heigths and the particles were characterized by PCS, microelectrophoresis, infrared spectra and analytical electron microscopy. The major fraction was opalescent and contained the colloidal crystals settled in the bottom of the liquid. Two other latex fractions were obtained, which differed in their chemical compositions, particle sizes and topochemical features from the self-arraying particles. Macrocrystallization of the fractionated latex yielded high quality crystals with a low frequency of defects, which confirms that particle chemical homogeneity is an important factor for particle self-arraying.

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

    African Journals Online (AJOL)

    ... to latex is a common problem among nurses and other health care workers. ... There was significant association between family history and occurrence of ... These effects may vary in severity from skin problems to anaphylactic shock.

  7. 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) propyl methacrylate) (PSPMA) macromonomers by quaternizing the tertiary amine end-group with excess 4-vinylbenzyl chloride, followed by esterification of the pendent hydroxyl groups using excess succinic anhydride at 20 °C. These polyacid macromonomers were evaluated as reactive steric stabilizers for polystyrene latex synthesis under either aqueous 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

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

    International Nuclear Information System (INIS)

    Parikh, G.C.; Ho, C.K.

    1977-01-01

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

  9. 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.

  10. 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 previ......The two existing theories describing drying of latex films or coatings are reconsidered. Subsequently, a novel mathematical drying model is presented, the simulations of which can match and explain experimental drying rate data of two previous investigations with latex films. In contrast...... to previous model studies, but in agreement with observations, simulations suggest that during the falling rate period of the drying process of a latex film, a porous skin of partly coalesced latex particles is indeed formed, which limits transport of water vapour from the receding air-liquid interphase...... to the surface of the film. The value of the effective diffusion coefficient of water vapour in the dry and partly coalesced layer (7 x 10(-7) m(2)/s at 19-24 degrees C), the adjustable parameter of the model for the falling rate period, was found to be independent of initial wet film thickness (89-1322 mu m...

  11. Ventricular assist device elicits serum natural IgG that correlates with the development of primary graft dysfunction following heart transplantation.

    Science.gov (United States)

    See, Sarah B; Clerkin, Kevin J; Kennel, Peter J; Zhang, Feifan; Weber, Matthew P; Rogers, Kortney J; Chatterjee, Debanjana; Vasilescu, Elena R; Vlad, George; Naka, Yoshifumi; Restaino, Susan W; Farr, Maryjane A; Topkara, Veli K; Colombo, Paolo C; Mancini, Donna M; Schulze, P Christian; Levin, Bruce; Zorn, Emmanuel

    2017-08-01

    Pre-transplant sensitization is a limiting factor in solid-organ transplantation. In heart transplants, ventricular assist device (VAD) implantation has been associated with sensitization to human leukocyte antigens (HLA). The effect of VAD on non-HLA antibodies is unclear. We have previously shown that polyreactive natural antibodies (Nabs) contribute to pre-sensitization in kidney allograft recipients. Here we assessed generation of Nabs after VAD implantation in pre-transplant sera and examined their contribution to cardiac allograft outcome. IgM and IgG Nabs were tested in pre-transplant serum samples collected from 206 orthotopic heart transplant recipients, including 128 patients with VAD (VAD patients) and 78 patients without VAD (no-VAD patients). Nabs were assessed by testing serum reactivity to apoptotic cells by flow cytometry and to the generic oxidized epitope, malondialdehyde, by enzyme-linked immunosorbent assay. No difference was observed in serum levels of IgM Nabs between VAD and no-VAD patients. However, serum IgG Nabs levels were significantly increased in VAD compared with no-VAD patients. This increase was likely due to the presence of the VAD, as revealed by lower serum IgG Nabs levels before implantation. Elevated pre-transplant IgG Nabs level was associated with development of primary graft dysfunction (PGD). Our study demonstrates that VAD support elicits IgG Nabs reactive to apoptotic cells and oxidized epitopes. These findings further support broad and non-specific B-cell activation by VAD, resulting in IgG sensitization. Moreover, the association of serum IgG Nabs levels with development of PGD suggests a possible role for these antibodies in the inflammatory reaction accompanying this complication. Copyright © 2017 International Society for the Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

  12. Processing cost of RVNRL (Radiation Vulcanised Natural Rubber Latex)

    International Nuclear Information System (INIS)

    Wan Manshol Wan Zin; Meor Yahya Razali; Norjanah Mohd

    1996-01-01

    The main components contributing to the cost of building a pilot plant for RVNRL are highlighted. The fixed cost and operating cost of a pilot plant were determined and the production capacity and the cost to prepare I kg of RVNRL were calculated. Two sets of calculations were presented. A set was based on a pilot plant installed with cobalt-60 source of 150 kCi and another set was based on a plant installed with cobalt-60 source of I MCi. The effect of different power utilisation efficiencies and the effect of different vulcanization doses on the production capacities are presented.In general, a small difference in the vulcanization dose and power utilisation efficiency result in a significant change in the production capacity and the cost for RVNRL preparation. Depending on the production capacity, the cost for preparing RVNRL of 50% total solid content can be as low as RM 0.242 per kilograms

  13. Bone Graft Alternatives

    Science.gov (United States)

    ... Spine Treatment Spondylolisthesis BLOG FIND A SPECIALIST Treatments Bone Graft Alternatives Patient Education Committee Patient Education Committee ... procedure such as spinal fusion. What Types of Bone Grafts are There? Bone grafts that are transplanted ...

  14. Ultraviolet curing of acrylated liquid natural rubber for surface coating application

    Directory of Open Access Journals (Sweden)

    Kannikar Kwanming

    2009-01-01

    Full Text Available Ultraviolet curable acrylated liquid natural rubber was prepared by grafting of photosensitive molecule onto liquid natural rubber for surface coating application. The liquid natural rubber (LNR was firstly obtained by degradation of natural rubber latex with hydrogen peroxide and cobalt acetylacetonate at 65oC for 72 hrs. The preparation of acrylated natural rubber was carried out by the reaction of acrylic acid and epoxidized liquid natural rubber (ELNR prior obtained from LNR with formic acid and hydrogen peroxide in the ratio of 2:1 by weight in toluene at 80oC for 6, 9, 12, 18, and 24 hrs. It was found that the percentage of acrylate grafted onto liquid natural rubber depended on the reaction time. Surface coating was performed by using acrylated liquid natural rubber and 1,6-hexanediol diacrylate (HDDA or tripropylene glycol diacrylate (TPGDA as a crosslinker and Irgarcure 184 or Irgarcure 651 as a photoinitiator under UV exposure for 30, 60, and 90 seconds. The hardness test of cured products was investigated using the Pencil hardness test at pencil level of 2B to 6H. It was found that the highest hardness of surface coating was at pencil level of 4H for the product using TPGDA and Irgacure 651 in the ratio of 80:10 parts per hundred of rubber (phr. The cured products were able to resist to 2% H2SO4 and distilled water for more than 24 hrs.

  15. Respiratory and dermal symptoms in Thai nurses using latex products.

    Science.gov (United States)

    Supapvanich, C; Povey, A C; de Vocht, F

    2013-09-01

    Despite known health risks related to the use of powdered latex gloves (PLGs), they are still widely used in hospitals in developing countries due to the high cost of alternatives. To determine the prevalence of dermal and respiratory symptoms associated with latex glove use in nurses in Thailand and evaluate the influence of previously reported occupational risk factors in this population. A cross-sectional study in female nurses working in three Thai hospitals. Participants completed a questionnaire on demographics, occupational and personal history, use of latex products at work and dermal and respiratory symptoms attributed to occupational use of latex gloves. Of 899 nurses, 18% reported health effects attributed to the use of latex products. After adjustment for confounding, occupational risk factors associated with increased reporting of dermal symptoms included wearing more than 15 pairs of PLG per day (odds ratio (OR): 2.10, 95% confidence interval (CI): [1.32-3.34]), using chlorhexidine (OR: 2.07, 95% CI: [1.22-3.52]) and being an operating theatre nurse (OR: 2.46, 95% CI: [1.47-4.12]). Being a labour ward nurse (OR: 3.52, 95% CI: [1.26-9.85]) was the only factor associated with increased reporting of respiratory symptoms. Continuing use of PLGs in Thai nurses is associated with increased prevalence of dermal symptoms compared with data from developed countries. Measures to reduce such health effects are well established and should be considered. Additionally, replacement of chlorhexidine with an alternative detergent seems advisable.

  16. A study on the morphology of polystyrene-grafted poly(ethylene-alt-tetrafluoroethylene) (ETFE) films prepared using a simultaneous radiation grafting method

    International Nuclear Information System (INIS)

    Song, Ju-Myung; Ko, Beom-Seok; Sohn, Joon-Yong; Nho, Young Chang; Shin, Junhwa

    2014-01-01

    The morphology of polystyrene-grafted poly(ethylene-alt-tetrafluoroethylene) (ETFE) films prepared using a simultaneous radiation grafting method was investigated using DMA, DSC, XRD, and SAXS instruments. The DMA study indicates that the ETFE amorphous phase and PS amorphous phase are mixed well in the PS-grafted ETFE films while the ETFE crystalline phase and the PS amorphous phase are separated, suggesting that the PS chains are grafted mainly on the ETFE amorphous regions. The DSC and XRD data showed that the natural crystalline structures of ETFE in the grafted ETFE films are not affected by the degree of grafting. The SAXS profiles displayed that the inter-crystalline distance of the ETFE films increases with an increasing degree of grafting, which further implies that the PS graft chains formed by the simultaneous irradiation has a significant impact on the amorphous morphology of the resulting grafted ETFE film. Thus, these results indicate that the styrene monomers are mainly grafted on the ETFE amorphous regions during the simultaneous radiation grafting process. - Highlights: • PS-grafted ETFE films were prepared by a simultaneous radiation grafting method was investigated. • The natural crystalline structures of grafted ETFE films are not affect by the degree of grafting. • The inter-crystalline distance of the ETFE films increase with increasing degree of grafting. • The styrene monomers are mainly grafted on the ETFE amorphous regions during a simultaneous radiation grafting using gamma-ray

  17. Latex-modified fiber-reinforced concrete bridge deck overlay : construction/interim report.

    Science.gov (United States)

    1993-06-01

    Latex-modified concrete (LMC) is Portland cement concrete (PCC) with an admixture of latex. LMC is considered to be nearly impermeable to chlorides and is extensively used to construct bridge deck overlays. Unfortunately, some of these overlays have ...

  18. Studies on physico-chemical and mechanical properties of the irradiated latex modified mortar

    International Nuclear Information System (INIS)

    Yassene, A.A.M.A.

    2009-01-01

    This thesis contains three chapter; chapter(I): Introduction and literature review on:- Introduction to polymer. - Mechanism of polymer-cement co-matrix formation.-Sulphate attack. - Solidification /stabilization of heavy metal in cement mortar. chapter(II): Materials and experimental techniques that include: 1- Preparation of latex polymer films from different polymer latices of styrene butadine rubber latex (SBR), poly (styrene-acrylic ester) latex (SAE) and vinylacetate /versatic -ester copolymer latex (C2A). The effect of γ-irradiation dose on the physico - chemical and mechanical properties of different latex polymer films was studied.2- Preparation of latex polymer-modified cement mortar with different ratios of cement: latex polymer and different curing method.3- Solidification /stabilization (S/S) of electroplating heavy metal precipitate in latex polymer- modified mortar with different cement /electroplating heavy metal sludge ratio. chapter(III) results and discussion

  19. 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

  20. 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

  1. IMMEDIATE AND DELAYED HYPERSENSITIVITY REACTIONS TO LATEX GLOVES IN A DENTAL STUDENT. A case report.

    Directory of Open Access Journals (Sweden)

    Iliyana Stoeva

    2011-08-01

    Full Text Available The article presents a case of dental student with immediate and delayed hypersensitivity reaction to latex gloves. Symptoms appeared during the second year of regularly using of latex gloves. The student was with no history of allergies and no previous exposure to latex products.

  2. Natural rubber producing plants: An overview | Venkatachalam ...

    African Journals Online (AJOL)

    ... Hevea and also other natural rubber producing species for alternative source of latex production in the near future. Keywords: Alternative rubber sources, biotechnology, breeding, Hevea brasiliensis, Parthenium argentatum, Taraxacum koksaghyz, Ficus bengalensis, Lactuca serriola. African Journal of Biotechnology Vol.

  3. Bone grafting: An overview

    Directory of Open Access Journals (Sweden)

    D. O. Joshi

    2010-08-01

    Full Text Available Bone grafting is the process by which bone is transferred from a source (donor to site (recipient. Due to trauma from accidents by speedy vehicles, falling down from height or gunshot injury particularly in human being, acquired or developmental diseases like rickets, congenital defects like abnormal bone development, wearing out because of age and overuse; lead to bone loss and to replace the loss we need the bone grafting. Osteogenesis, osteoinduction, osteoconduction, mechanical supports are the four basic mechanisms of bone graft. Bone graft can be harvested from the iliac crest, proximal tibia, proximal humerus, proximal femur, ribs and sternum. An ideal bone graft material is biologically inert, source of osteogenic, act as a mechanical support, readily available, easily adaptable in terms of size, shape, length and replaced by the host bone. Except blood, bone is grafted with greater frequency. Bone graft indicated for variety of orthopedic abnormalities, comminuted fractures, delayed unions, non-unions, arthrodesis and osteomyelitis. Bone graft can be harvested from the iliac crest, proximal tibia, proximal humerus, proximal femur, ribs and sternum. By adopting different procedure of graft preservation its antigenicity can be minimized. The concept of bone banking for obtaining bone grafts and implants is very useful for clinical application. Absolute stability require for successful incorporation. Ideal bone graft must possess osteogenic, osteoinductive and osteocon-ductive properties. Cancellous bone graft is superior to cortical bone graft. Usually autologous cancellous bone graft are used as fresh grafts where as allografts are employed as an alloimplant. None of the available type of bone grafts possesses all these properties therefore, a single type of graft cannot be recomm-ended for all types of orthopedic abnormalities. Bone grafts and implants can be selected as per clinical problems, the equipments available and preference of

  4. Rubber elongation factor (REF, a major allergen component in Hevea brasiliensis latex has amyloid properties.

    Directory of Open Access Journals (Sweden)

    Karine Berthelot

    Full Text Available REF (Hevb1 and SRPP (Hevb3 are two major components of Hevea brasiliensis latex, well known for their allergenic properties. They are obviously taking part in the biosynthesis of natural rubber, but their exact function is still unclear. They could be involved in defense/stress mechanisms after tapping or directly acting on the isoprenoid biosynthetic pathway. The structure of these two proteins is still not described. In this work, it was discovered that REF has amyloid properties, contrary to SRPP. We investigated their structure by CD, TEM, ATR-FTIR and WAXS and neatly showed the presence of β-sheet organized aggregates for REF, whereas SRPP mainly fold as a helical protein. Both proteins are highly hydrophobic but differ in their interaction with lipid monolayers used to mimic the monomembrane surrounding the rubber particles. Ellipsometry experiments showed that REF seems to penetrate deeply into the monolayer and SRPP only binds to the lipid surface. These results could therefore clarify the role of these two paralogous proteins in latex production, either in the coagulation of natural rubber or in stress-related responses. To our knowledge, this is the first report of an amyloid formed from a plant protein. This suggests also the presence of functional amyloid in the plant kingdom.

  5. Effect of lithium salt concentrations on blended 49% poly(methyl methacrylate) grafted natural rubber and poly(methyl methacrylate) based solid polymer electrolyte

    International Nuclear Information System (INIS)

    Su’ait, M.S.; Ahmad, A.; Hamzah, H.; Rahman, M.Y.A.

    2011-01-01

    The effect of lithium salts (lithium tetrafluoroborate, LiBF 4 and lithium perchlorate, LiClO 4 ) as doping salts in rubber-polymer blends, 49% poly(methyl methacrylate) grafted natural rubber (MG49) and poly(methyl methacrylate) (PMMA) in solid polymer electrolyte (SPE) film for electrochemical devices application was investigated. The electrolyte films were prepared via the solution casting technique using 0–25 wt.% lithium salt. The effect of the lithium salts on chemical interaction, ionic conductivity and structural and morphological studies of (70:30) MG49-PMMA films was analyzed using Fourier Transform Infrared (FT-IR) Spectroscopy, Electrochemical Impedance Spectroscopy (EIS), X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). Infrared analysis showed that the interactions between lithium ions and oxygen atoms occur at the ether group (C–O–C) (1500–1100 cm −1 ) on the MMA structure in both MG49 and PMMA. The oxygen atoms in the structure of the polymer host act as electron donor atoms and form a coordinate bond with the lithium ions from the doping salt to form polymer–salt complexes. The ionic conductivity was investigated at room temperature as well as at a temperature range from 303 K to 373 K. The ionic conductivity without the addition of salt was 1.1 × 10 −12 S cm −1 . The highest conductivity at room temperature for (70:30) MG49-PMMA–LiBF 4 was 8.6 × 10 −6 S cm −1 at 25 wt.% of LiBF 4 . The ionic conductivity of (70:30) MG49-PMMA–LiClO 4 was 1.5 × 10 −8 S cm −1 at 25 wt.% of LiClO 4 . However, both electrolyte systems do not exhibit Arrhenius-like behavior. Systems with LiBF 4 salt have higher ionic conductivity than those with LiClO 4 salt because of the differences in anionic size and lattice energy of the appropriate salt. The observations from structural and morphology studies showed that complexation and re-crystallization occur in the system. The XRD studies showed a reduction of the MMA peak

  6. Polybutadiene latex particle size distribution analysis utilizing a disk centrifuge

    NARCIS (Netherlands)

    Verdurmen, E.M.F.J.; Albers, J.G.; German, A.L.

    1994-01-01

    Polybutadiene (I) latexes prepd. by emulsifier-free emulsion polymn. and having particle diam. 50-300 nm for both unimodal and bimodal particles size distributions were analyzed by the line-start (LIST) method in a Brookhaven disk centrifuge photosedimentometer. A special spin fluid was designed to

  7. 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.

  8. Oil-Acrylic hybrid latexes as binders for waterborne coatings

    NARCIS (Netherlands)

    Hamersveld, E.M.S.; Es, van J.J.G.S.; 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

  9. 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

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

    International Nuclear Information System (INIS)

    Razali Hamzah; Muhd Khairi Muhd Said; Muhd Ariff Hamzah; Wan Manshol Wan Zin; Taiman Kadni

    1996-01-01

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

  11. Study of glucoamylase immobilization in butadiene nitrile latex membrane

    International Nuclear Information System (INIS)

    Miller, E.

    1992-01-01

    Attempts have been undetaken to immobilize glucoamylaze by means of butadiene nitrile latex in the presence of a chemical initiator and 60 Co γ-radiation. The activity, stability of conjugates in the membrane and permeability of oxygen in these membranes were determined. (author) 14 refs.; 5 figs

  12. Acetylcholinesterase Inhibitory and Antioxidant Properties of Euphorbiacharacias Latex

    Directory of Open Access Journals (Sweden)

    Francesca Pintus

    2013-03-01

    Full Text Available The aim of the present study was to evaluate the acetylcholinesterase inhibitory capacity and the antioxidant properties of extracts of Euphorbia characias latex, a Mediterranean shrub. We performed a new extraction method involving the use of the trichloroacetic acid. The extract showed high antioxidant activity, was rich in total polyphenolic and flavonoid content and exhibited substantial inhibition of acetylcholinesterase activity.

  13. 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.

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

    African Journals Online (AJOL)

    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 gloves. The need for anaesthetists to effectively diagnose and properly manage this rare clinical entity is ...

  15. Partial swelling of latex particles by two monomers

    NARCIS (Netherlands)

    Noel, E.F.J.; Maxwell, I.A.; German, A.L.

    1993-01-01

    The swelling of polymeric latex particles with solvent and monomer is of great importance for the emulsion polymn. process in regard to compn. drift and rate of polymn. For the monomer combination, Me acrylate-vinyl acetate, both satn. and partial swelling were detd. exptl. Theories for satn.

  16. Improvement of polymer stability by radiation grafting

    International Nuclear Information System (INIS)

    Ranogajec, F.; Mlinac-Misak, M.

    1999-01-01

    Losses of the stabilizer due to extractability or volatility immediately affect ultimate performance of polymer product. A new approach to increase the persistence of the stabilizer in the final product is to chemically bind it to the polymer backbone. Radiation grafting or crosslinking could be an efficient method for this, when the stabilizer is polymerizable. By a mutual gamma irradiation method, photoprotector 2-hydroxy-4-(3-methacryloxy-2- hydroxy-propoxy) benzophenone (HMB) has been readily grafted to low density polyethylene (LDPE) in benzene, tetrahydrofuran and methanol solution, respectively. Surface grafting occurs in a methanol solution of stabilizer, while in benzene and tetrahydrofuran solutions of stabilizer, grafting proceeds more or less in the inner parts of the polymeric film as well. The grafted LDPE film in methanol and tetrahydrofuran (containing 1 w/w % of grafted HMB), 1 w/w % blended HMB with LDPE and nongrafted LDPE film, were all exposed to accelerated aging and natural weathering and their spectral changes, expressed by the carbonyl index, were then compared. The change of elongation at break and tensile strength were measured in the course of aging. UV stability tests on aged films and change in mechanical properties indicate a pronounced protective effect achieved by grafted stabilizer. Grafting in methanol solution appears to be an efficient photostabilization treatment and the most economical with respect to the consumption of monomer, the grafting yield being less than 0.5%. Surface grafting is an efficient photostabilization method since grafted stabilizer is chemically bound to a polymeric surface and in this way the problem of evaporation of blended stabilizers during the prolonged use of polymeric materials is eliminated. (author)

  17. Synthesis of graft copolymers onto starch and its semiconducting properties

    Directory of Open Access Journals (Sweden)

    Nevin Çankaya

    Full Text Available Literature review has revealed that, although there are studies about grafting on natural polymers, especially on starch, few of them are about electrical properties of graft polymers. Starch methacrylate (St.met was obtained by esterification of OH groups on natural starch polymer for this purpose. Grafting of synthesized N-cyclohexyl acrylamide (NCA and commercial methyl methacrylate (MMA monomers with St.met was done by free radical polymerization method. The graft copolymers were characterized with FT-IR spectra, thermal and elemental analysis. Thermal stabilities of the graft copolymers were determined by TGA (thermo gravimetric analysis method and thermal stability of the copolymers is decreased via grafting. The electrical conductivity of the polymers was measured as a function of temperature and it has been observed that electrical conductivity increases with increasing temperature. The absorbance and transmittance versus wavelength of the polymers have been measured. Keywords: Starch, Graft copolymer, Semiconducting, Thermal stability, Starch methacrylate

  18. Grafting and curing

    International Nuclear Information System (INIS)

    Garnett, J.L.; Loo-Teck Ng; Visay Viengkhou

    1998-01-01

    Progress in radiation grafting and curing is briefly reviewed. The two processes are shown to be mechanistically related. The parameters influencing yields are examined particularly for grafting. For ionising radiation grafting systems (EB and gamma ray) these include solvents, substrate and monomer structure, dose and dose-rate, temperature and more recently role of additives. In addition, for UV grafting, the significance of photoinitiators is discussed. Current applications of radiation grafting and curing are outlined. The recent development of photoinitiator free grafting and curing is examined as well as the potential for the new excimer laser sources. The future application of both grafting and curing is considered, especially the significance of the occurrence of concurrent grafting during cure and its relevance in environmental considerations

  19. Skin graft - slideshow

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/presentations/100100.htm Skin graft - series—Normal anatomy To use the sharing features ... entire body, and acts as a protective barrier. Skin grafts may be recommended for: Extensive wounds Burns Specific ...

  20. Caracterização da hipersensibilidade a luvas de látex em profissionais da odontologia = Rubber latex gloves hypersensitivities in dental workers

    Directory of Open Access Journals (Sweden)

    Flávia Sukekava

    2007-01-01

    Full Text Available As reações alérgicas ao látex vêm aumentando em profissionais da saúde e se manifestam como um incômodo local ou sintomatologia sistêmica. Para conhecer a freqüência das manifestações alérgicas nos usuários de luvas de látex foi realizada busca entre os profissionais da odontologia via aplicação de questionários. Foram aplicados 450questionários e, dentre os respondedores (140, 19% relataram manifestar reações locais ao contato com as luvas de látex e 5% reações sistêmicas a outros produtos de látex. Cerca de 2,5% declararam dermatite de contato e reações sistêmicas (anafiláticas, 1,5% apenas dermatite de contato e 1% sintomas de anafilaxia ao uso das luvas. Vinte por cento dos profissionais atenderam pacientes com alergia ao látex e 29% declararam questionar, durante a anamnese, a respeito de alergia ao látex. As reações alérgicas a luvas de látex foram freqüentes e é objeto de preocupação entre os profissionais da odontologia.Allergic reactions to natural rubber latex have increased in dental practice affecting both the professional and the patients. Allergic reactions may range from skin disease to asthma and anaphylaxis. This study aimed at determining the incidence of latex gloves allergy amongdental care workers. 450 allergy questionnaires were used to collect information on latex gloves reactions and 140 dental works answered them. Latex gloves reaction occurred in 19% of them and 5% reported allergic reactions to other latex products. 2.5% reported symptoms suggesting contact dermatitis and anaphylaxis hypersensitivities, 1.5% contact dermatitis, and 1% reported anaphylaxis symptoms when wearing them. 20% of them had patients who presented symptoms suggestive of anaphylaxis hypersensitivity to rubber gloves latex. Our study confirms that rubber latex gloves reactions are frequent among dental care workers, and dentists must be aware of the latex allergy in dental practice.

  1. A Mixed Application of Geographically Weighted Regression and Unsupervised Classification for Analyzing Latex Yield Variability in Yunnan, China

    Directory of Open Access Journals (Sweden)

    Oh Seok Kim

    2017-05-01

    Full Text Available This paper introduces a mixed method approach for analyzing the determinants of natural latex yields and the associated spatial variations and identifying the most suitable regions for producing latex. Geographically Weighted Regressions (GWR and Iterative Self-Organizing Data Analysis Technique (ISODATA are jointly applied to the georeferenced data points collected from the rubber plantations in Xishuangbanna (in Yunnan province, south China and other remotely-sensed spatial data. According to the GWR models, Age of rubber tree, Percent of clay in soil, Elevation, Solar radiation, Population, Distance from road, Distance from stream, Precipitation, and Mean temperature turn out statistically significant, indicating that these are the major determinants shaping latex yields at the prefecture level. However, the signs and magnitudes of the parameter estimates at the aggregate level are different from those at the lower spatial level, and the differences are due to diverse reasons. The ISODATA classifies the landscape into three categories: high, medium, and low potential yields. The map reveals that Mengla County has the majority of land with high potential yield, while Jinghong City and Menghai County show lower potential yield. In short, the mixed method can offer a means of providing greater insights in the prediction of agricultural production.

  2. Bone grafts in dentistry

    Directory of Open Access Journals (Sweden)

    Prasanna Kumar

    2013-01-01

    Full Text Available Bone grafts are used as a filler and scaffold to facilitate bone formation and promote wound healing. These grafts are bioresorbable and have no antigen-antibody reaction. These bone grafts act as a mineral reservoir which induces new bone formation.

  3. Effect of SiO 2-ZrO 2 supports prepared by a grafting method on hydrogen production by steam reforming of liquefied natural gas over Ni/SiO 2-ZrO 2 catalysts

    Science.gov (United States)

    Seo, Jeong Gil; Youn, Min Hye; Song, In Kyu

    SiO 2-ZrO 2 supports with various zirconium contents are prepared by grafting a zirconium precursor onto the surface of commercial Carbosil silica. Ni(20 wt.%)/SiO 2-ZrO 2 catalysts are then prepared by an impregnation method, and are applied to hydrogen production by steam reforming of liquefied natural gas (LNG). The effect of SiO 2-ZrO 2 supports on the performance of the Ni(20 wt.%)/SiO 2-ZrO 2 catalysts is investigated. SiO 2-ZrO 2 prepared by a grafting method serves as an efficient support for the nickel catalyst in the steam reforming of LNG. Zirconia enhances the resistance of silica to steam significantly and increases the interaction between nickel and the support, and furthermore, prevents the growth of nickel oxide species during the calcination process through the formation of a ZrO 2-SiO 2 composite structure. The crystalline structures and catalytic activities of the Ni(20 wt.%)/SiO 2-ZrO 2 catalysts are strongly influenced by the amount of zirconium grafted. The conversion of LNG and the yield of hydrogen show volcano-shaped curves with respect to zirconium content. Among the catalysts tested, the Ni(20 wt.%)/SiO 2-ZrO 2 (Zr/Si = 0.54) sample shows the best catalytic performance in terms of both LNG conversion and hydrogen yield. The well-developed and pure tetragonal phase of ZrO 2-SiO 2 (Zr/Si = 0.54) appears to play an important role in the adsorption of steam and subsequent spillover of steam from the support to the active nickel. The small particle size of the metallic nickel in the Ni(20 wt.%)/SiO 2-ZrO 2 (Zr/Si = 0.54) catalyst is also responsible for its high performance.

  4. LOL2 and LOL5 loci control latex production by laticifer cells in Euphorbia lathyris.

    Science.gov (United States)

    Castelblanque, Lourdes; Balaguer, Begoña; Marti, Cristina; Orozco, Marianela; Vera, Pablo

    2018-06-07

    Laticifers are specialized plant cells capable of indefinite elongation that ramify extensively and are responsible for latex biosynthesis and accumulation. However, the mechanisms underlying laticifer cell differentiation, growth and production of latex remain largely unknown. In a search for mutants showing enhanced accumulation of latex we identified two LOT OF LATEX (LOL) loci in Euphorbia lathyris. lol2 and lol5 mutants show enhanced production of latex contained within laticifer cells. The recessive lol2 mutant carries increased biosynthesis of the plant hormone jasmonoyl-isoleucine (JA-Ile) and therefore establishes a genetic link between jasmonic acid (JA) signaling and latex production in laticifers. Instead, heightened production of latex in lol5 plants obeys to enhanced proliferation of laticifer cells. Phylogenetic analysis of laticifer-expressed genes in E. lathyris and in two other latex-bearing species, Euphorbia corallioides and Euphorbia palustris, allowed the identification of canonical JA responsive elements present in the gene promoter regions of laticifer marker genes. Moreover, we identified that the hormone JA functions not as a morphogen for laticifer differentiation but as a trigger for the fill out of laticifers with latex and the associated triterpenoids. The identification of LOL loci represents a further step towards the understanding of mechanisms controlling latex production in laticifer cells. No claim to original US Government works New Phytologist © 2018 New Phytologist Trust.

  5. Controlling adsorption of albumin with hyaluronan on silica surfaces and sulfonated latex particles.

    Science.gov (United States)

    Berts, Ida; Fragneto, Giovanna; Porcar, Lionel; Hellsing, Maja S; Rennie, Adrian R

    2017-10-15

    Polysaccharides are known to modify binding of proteins at interfaces and this paper describes studies of these interactions and how they are modified by pH. Specifically, the adsorption of human serum albumin on to polystyrene latex and to silica is described, focusing on how this is affected by hyaluronan. Experiments were designed to test how such binding might be modified under relevant physiological conditions. Changes in adsorption of albumin alone and the co-adsorption of albumin and hyaluronan are driven by electrostatic interactions. Multilayer binding is found to be regulated by the pH of the solution and the molecular mass and concentration of hyaluronan. Highest adsorption was observed at pH below 4.8 and for low molecular mass hyaluronan (≤150kDa) at concentrations above 2mgml -1 . On silica with grafted hyaluronan, albumin absorption is reversed by changes in solvent pH due to their strong electrostatic attraction. Albumin physisorbed on silica surfaces is also rinsed away with dilute hyaluronan solution at pH 4.8. The results demonstrate that the protein adsorption can be controlled both by changes of pH and by interaction with other biological macromolecules. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Osmotic de-swelling and swelling of latex dispersions

    International Nuclear Information System (INIS)

    Bonnet-Gonnet, Cecile

    1993-01-01

    This research thesis reports the comparison of, on the one hand, direct measurements of de-swelling resistance of latex dispersions obtained by osmotic pressure with, on the other hand, predictions made by models of electrostatic interactions. This resistance is explained in the case of sulphate-stabilised polystyrene particles (direct repulsion between charged particles), and in the case of copolymer (ps-pba) particles covered by an amphiphilic polymer (interactions between surface macromolecules and polymers). The study of de-swelling and swelling cycles highlights the existence of thresholds beyond which the concentrated dispersion has some cohesion. This irreversibility can be modelled by a Van der Waals attraction. The role of hydrophobic forces in latex destabilisation is studied [fr

  7. [Anaphylactic reaction to latex during spinal anesthesia: a case report].

    Science.gov (United States)

    Ueda, Narumi; Kitamura, Rie; Wakamori, Takeshi; Nakamura, Kumi; Konishi, Keisuke

    2008-05-01

    A 46-year-old man, with a history of atopic dermatitis and bronchial asthma, underwent surgery for an inguinal hernia. Forty-three minutes subsequent to spinal anesthesia, the patient complained suddenly of dyspnea with wheezing. Blood pressure decreased and skin eruption was observed on his chest. Postoperative laboratory tests revealed high IgE concentration, and a skin test confirmed an allergy to latex. The patient's allergic reaction was easily overlooked because of his history of bronchial asthma and the possibility that the hypotension was caused by the high spinal anesthesia. Latex allergy should be considered in any suspicious case presenting with these symptoms during surgery. After recovery, a skin test should be used to confirm the allergy to avoid repeated allergic episodes.

  8. A latex metabolite benefits plant fitness under root herbivore attack

    OpenAIRE

    Huber, M.; Epping, J.; Gronover, C.S.; Fricke, J.; Aziz, Z.; Brillatz, T.; Swyers, M.; Köllner, T.G.; Vogel, H.; Hammerbacher, A.; Triebwasser-Freese, D.; Robert, C.A.M.; Verhoeven, K.; Preite, V.; Gershenzon, J.

    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 n...

  9. Minimizing surgical skin incision scars with a latex surgical glove.

    Science.gov (United States)

    Han, So-Eun; Ryoo, Suk-Tae; Lim, So Young; Pyon, Jai-Kyung; Bang, Sa-Ik; Oh, Kap-Sung; Mun, Goo-Hyun

    2013-04-01

    The current trend in minimally invasive surgery is to make a small surgical incision. However, the excessive tensile stress applied by the retractors to the skin surrounding the incision often results in a long wound healing time and extensive scarring. To minimize these types of wound problems, the authors evaluated a simple and cost-effective method to minimize surgical incision scars based on the use of a latex surgical glove. The tunnel-shaped part of a powder-free latex surgical glove was applied to the incision and the dissection plane. It was fixed to the full layer of the dissection plane with sutures. The glove on the skin surface then was sealed with Ioban (3 M Health Care, St. Paul, MN, USA) to prevent movement. The operation proceeded as usual, with the retractor running through the tunnel of the latex glove. It was possible to complete the operation without any disturbance of the visual field by the surgical glove, and the glove was neither torn nor separated by the retractors. The retractors caused traction and friction during the operation, but the extent of damage to the postoperative skin incision margin was remarkably less than when the operation was performed without a glove. This simple and cost-effective method is based on the use of a latex surgical glove to protect the surgical skin incision site and improve the appearance of the postoperative scar. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

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

    International Nuclear Information System (INIS)

    Razali Hamzah; Muhd Khairi Muhd Said; Muhd Ariff Hamzah; Wan Manshol Wan Zin; Wan Abd Hadi Wan Abu Bakar; Muhd Noor Muhd Yunus

    1996-01-01

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

  11. The polymerization of aniline in polystyrene latex particles

    Czech Academy of Sciences Publication Activity Database

    Blinova, Natalia V.; Reynaud, S.; Roby, F.; Trchová, Miroslava; Stejskal, Jaroslav

    2010-01-01

    Roč. 160, 15/16 (2010), s. 1598-1602 ISSN 0379-6779 R&D Projects: GA AV ČR IAA400500905; GA ČR GA203/08/0686; GA ČR GA202/09/1626 Institutional research plan: CEZ:AV0Z40500505 Keywords : polyaniline * polystyrene latex * polyaniline-polystyrene composite Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.871, year: 2010

  12. Efficacy of protection by latex gloves during orthodontic therapy.

    Science.gov (United States)

    Doll, G M; Zentner, A; Balan, R; Sergl, H G

    2000-01-01

    The wearing of gloves during orthodontic or dental treatment is generally indicated for reasons of hygiene and protection against infection. This study was aimed at determining the extent and localization of perforations caused by the various orthodontic treatment techniques and interrupting the infection barrier. The impermeability was tested by means of a water retention test according to European standard EN 455, Part 1, performed on 1600 Centramed (Centramed, Koblenz), Tekmedic and SafeEx non-sterile disposable latex gloves (both by Safe Med, Switzerland) and Safe Gan latex gloves with an additional acrylate coating (also by Safe Med). The perforation rate in unused gloves was between 0.5% and 7.5%, rising on average to 11% with increasing use. 36% of the total number of lesions resulted from handling removable appliances, and 57% from handling fixed appliances, especially when replacing arch wires and elastics. Most lesions were in the thumb, index finger and palm region. Only 18% of the defects were noticed by the dentists themselves. The gloves worn by beginners in their first year of postgraduate orthodontic training had about twice as many defects as those worn by qualified orthodontists. When patients with an increased risk of infection are to be treated, additional hand disinfection measures should be taken and 2 pairs of gloves worn in view of the relatively unreliable protection offered by commercially available latex gloves.

  13. 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.

  14. Latex agglutination test (LAT) for the diagnosis of typhoid fever.

    Science.gov (United States)

    Sahni, Gopal Shankar

    2013-06-01

    The efficacy of latex agglutination test in the rapid diagnosis of typhoid fever was studied and the result compared with that of blood culture. This study included 80 children suffering from typhoid fever, among which 40 were confirmed by blood culture isolation and 40 had possible typhoid fever based on high Widal's titre (a four-fold rise in the titre of antibody to typhi "O" and "H" antigen was considered as a positive Widal's test result). Eighty children, 40 with febrile illness confirmed to be other than typhoid and 40 normal healthy children were used as negative controls. The various groups were: (i) Study group ie, group I had 40 children confirmed by culture isolation of Salmonella typhi(confirmed typhoid cases). (ii) Control groups ie, (a) group II with 40 febrile controls selected from paediatrics ward where cause other than S typhi has been established, (b) group III with 40 afebrile healthy controls that were siblings of the children admitted in paediatric ward for any reason with no history of fever and TAB vaccination in the last one year, and (c) group IV with 40 children with high Widal's titre in paired sera sample. Widal's test with paired sera with a one week interval between collections were done in all 40 patients. Latex aggtutination test which could detect 900 ng/ml of antigen as observed in checker board titration, was positive in all 40 children from group I who had positive blood culture and in 30 children from group IV who had culture negative and had high Widal's titre positive. Latex agglutination test was positive in 4 children in group II and none in group III. Using blood culture positive cases as true positive and children in groups II and III as true negative, the test had a sensitivity of 100% and specificity of 96%. Latex agglutination test was found to be significantly sensitive (100%) and specific (96%) and could detect 75% more cases in group IV (possible typhoid cases). Thus latex agglutination test can be used for rapid

  15. Detection and toxicity assessment of nitrosamines migration from latex gloves in the Chinese market.

    Science.gov (United States)

    Feng, Di; Wang, Huiping; Cheng, Xuelian; Wang, Jiedong; Ning, Lifeng; Zhou, Qingfeng; Zhou, Yue; Yang, Quanli

    2009-09-01

    Nitrosamines are potent carcinogens and have been found in latex products. In 2007, twenty-seven natural latex gloves including sterile gloves, examination gloves and household use gloves were sampled from the Chinese market. This study monitored the migration of nitrosamines and nitrosatable substance from these gloves, and evaluated their mutagenicity using a Salmonella typhimurium mutation assay (Ames assay) with the strains TA98, TA97, TA100 and TA102 and by a micronucleus test (MN test) using ICR mice. In addition, the cytotoxicity of these compounds was determined by a MTT assay. N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA) and N-nitrosodibutylamine (NDBA) were all found in samples treated with artificial sweat for 4h at 37 degrees C, and total nitrosamines varied from 18.89 to 244.51microg/Kg. The nitrosamine mixture of NDMA, NDEA and NDBA was used in both the Ames assay and the MN test. The proportion of NDMA, NDEA and NDBA (1:10:20) was selected according to the proportion of nitrosamines migration from sample E05. In the Ames assay, the lowest dose (1.98 x 10(-3)microg per plate) produced a positive result in the TA98 strain, corresponding to nitrosamines migration from sample E05 of 0.016g (the total nitrosamines migration from glove E05 was 122.55 microg/kg). The TA100 strain responded positively at a dose of 4.96 x 10(-2)microg per plate, corresponding to nitrosamines migration from glove E05 of 0.040g. The MN test showed nitrosamine migration of 3.04 mg from 2066 pairs of sample E05 and could induce micronuclei in one mouse weighing 28g (average weight of one E05 glove was 6g). Extracts from gloves were found to be cytotoxic and there was a significant correlation between cytotoxicity (IC50) and the release level of nitrosamines. In conclusion, in view of the high content of nitrosamines in latex gloves and the potential toxicity of nitrosamines migration from these gloves, it is suggested that both an effective and feasible detection

  16. Osseous scintigraphy and auxiliary graft

    International Nuclear Information System (INIS)

    Khelifa, F.; Siles, S.; Puech, B.

    1992-01-01

    The scintigraphy could be a good way to survey the osseous graft: three cases are studied in which were recognized the presence of a graft, surinfection, graft lysis, pseudo-arthrosis, algodystrophy. 8 refs., 5 figs

  17. Meniscal allograft transplantation. Part 1: systematic review of graft biology, graft shrinkage, graft extrusion, graft sizing, and graft fixation.

    Science.gov (United States)

    Samitier, Gonzalo; Alentorn-Geli, Eduard; Taylor, Dean C; Rill, Brian; Lock, Terrence; Moutzouros, Vasilius; Kolowich, Patricia

    2015-01-01

    To provide a systematic review of the literature regarding five topics in meniscal allograft transplantation: graft biology, shrinkage, extrusion, sizing, and fixation. A systematic literature search was conducted using the PubMed (MEDLINE), ScienceDirect, and EBSCO-CINAHL databases. Articles were classified only in one topic, but information contained could be reported into other topics. Information was classified according to type of study (animal, in vitro human, and in vivo human) and level of evidence (for in vivo human studies). Sixty-two studies were finally included: 30 biology, 3 graft shrinkage, 11 graft extrusion, 17 graft size, and 6 graft fixation (some studies were categorized in more than one topic). These studies corresponded to 22 animal studies, 22 in vitro human studies, and 23 in vivo human studies (7 level II, 10 level III, and 6 level IV). The principal conclusions were as follows: (a) Donor cells decrease after MAT and grafts are repopulated with host cells form synovium; (b) graft preservation alters collagen network (deep freezing) and causes cell apoptosis with loss of viable cells (cryopreservation); (c) graft shrinkage occurs mainly in lyophilized and gamma-irradiated grafts (less with cryopreservation); (d) graft extrusion is common but has no clinical/functional implications; (e) overall, MRI is not superior to plain radiograph for graft sizing; (f) graft width size matching is more important than length size matching; (g) height appears to be the most important factor influencing meniscal size; (h) bone fixation better restores contact mechanics than suture fixation, but there are no differences for pullout strength or functional results; and (i) suture fixation has more risk of graft extrusion compared to bone fixation. Systematic review of level II-IV studies, Level IV.

  18. 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

  19. 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.

  20. Laboratory evaluation of a simple and rapid latex agglutination assay for the serodiagnosis of typhoid fever

    NARCIS (Netherlands)

    Abdoel, Theresia H.; Pastoor, Rob; Smits, Henk L.; Hatta, Mochammad

    2007-01-01

    A latex agglutination assay for the serodiagnosis of typhoid fever was evaluated on samples collected from patients with clinical suspicion of typhoid fever in South Sulawesi, Indonesia, where the disease is endemic. The latex assay is very easy to use, gives a rapid result and may be used as a

  1. 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

    2015-01-01

    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. PMID:26247941

  2. Isotactic polypropylene/carbon nanotube composites prepared by latex technology: Electrical conductivity study

    NARCIS (Netherlands)

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

    2010-01-01

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

  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. Thermodynamics of swelling of latex particles with two monomers: a sensitivity analysis

    NARCIS (Netherlands)

    Maxwell, I.A.; Noel, E.F.J.; Schoonbrood, H.A.S.; German, A.L.

    1993-01-01

    A sensitivity anal. is performed to det. at what conditions the simplified model for swelling of latex particles by two monomers or two solvents is valid. This model proposes that, inter alia, the fractions of two monomers in the latex particles and in the monomer droplets are equal. The model is a

  5. Towards anti-corrosion coatings from surfactant-free latexes based on maleic anhydride containing polymers

    NARCIS (Netherlands)

    Soer, W.J.; Ming, W.; Koning, C.E.; Benthem, van R.A.T.M.

    2008-01-01

    We report on the film formation of surfactant-free, artificial latexes based on copolymers containing maleic anhydride. Different metallic substrates, such as aluminum, steel and magnesium alloys, were coated with three different latexes. A commercial polyester based coating was used as a

  6. Residual monomer reduction in polymer latex products by extraction with supercritical carbon dioxide

    NARCIS (Netherlands)

    Aerts, M.; Meuldijk, J.; Kemmere, M.F.; Keurentjes, J.T.F.

    2011-01-01

    Extraction of residual monomer from a latex product with supercritical carbon dioxide ((sc)CO2) in a column was studied. Operating conditions were chosen at 35¿°C and 100 bar. For reducing the residual styrene level in a polystyrene latex from 104 ppm to 100¿ppm and from 104 ppm to 10¿ppm, a

  7. 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....

  8. Advances in radiation grafting

    International Nuclear Information System (INIS)

    Hegazy, El-Sayed A.; AbdEl-Rehim, H.A.; Kamal, H.; Kandeel, K.A.

    2001-01-01

    Graft copolymerization is an attractive means for modifying base polymers because grafting frequently results in the superposition of properties relating to the backbone and pendent chains. Among the various methods for initiating the grafting reaction, ionizing radiation is the cleanest and most versatile method of grafting available. Ion-exchange membranes play an important role in modern technology, especially in separation and purification of materials. The search for improved membrane composition has considered almost every available polymeric material because of its great practical importance. Grafting of polymers with a mixture of monomers is important since different types of chains containing different functional groups are included. A great deal is focused on the waste treatment of heavy and toxic metals from wastewater because of the severe problems of environmental pollution. Functionalized polymers suitable for metal adsorption with their reactive functional groups such as carboxylic and pyridine groups suitable for waste treatment were prepared by radiation grafting method. More reactive chelating groups were further introduced to the grafted copolymer through its functional groups by chemical treatments with suitable reagents. The advances of radiation grafting and possible uses are briefly discussed

  9. Bone graft revascularization strategies

    NARCIS (Netherlands)

    Willems, W.F.

    2014-01-01

    Reconstruction of avascular necrotic bone by pedicled bone grafting is a well-known treatment with little basic research supporting its application. A new canine model was used to simulate carpal bone avascular necrosis. Pedicled bone grafting proved to increase bone remodeling and bone blood flow,

  10. 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

  11. A Reappraisal of Online Mathematics Teaching Using LaTeX

    Directory of Open Access Journals (Sweden)

    Eamon Costello

    2009-12-01

    Full Text Available The mathematics language LaTeX is often seen outside of academic circles as a legacy technology that is awkward to use. MathML - a verbose language designed for data-exchange, and to be written and understood by machines - is sometimes by contrast seen as something that will aid online mathematics and lack of browser support for it bemoaned. However LaTeX can already do many of the things that MathML might promise. LaTeX is here proposed as a language from which small fragments, with concise syntax, can be used by people to easily create and share mathematical expressions online. The capability to embed fragments of LaTeX code in online discussions is described here and its impact on a group of educators and learners evaluated. Here LaTeX is posited as a useful tool for facilitating asynchronous, online, collaborative learning of mathematics.

  12. 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.

  13. Insolubilisation of biologically active materials with novel radiation graft copolymers

    International Nuclear Information System (INIS)

    Garnett, J.L.; Jankiewicz, S.V.; Levot, R.; Sangster, D.F.

    1984-01-01

    The use of radiation grafting to immobilise a typical enzyme, trypsin, is reported. The technique involves radiation grafting to a backbone polymer a monomer containing an appropriate functional group to which the enzyme is bonded. In the present work, p-nitrostyrene has been grafted to representative trunk polymers, polypropylene and PVC, the nitro group in the resulting copolymer converted to the isothiocyanato derivative to which trypsin is attached. Of importance to this insolubilisation process, especially for radiation sensitive backbone polymers, is the inclusion of additives which enhance grafting. A new class of additives which increase the grafting yields is reported using as representative backbone polymers, naturally occurring cellulose and synthetic low density polyethylene. The new additives are specific metal salts such as LiClO 4 . The reactivity of these salts in grafting enhancement has been compared with that of mineral acid which has previously been used as an additive to increase grafting yields in both preirradiation and simultaneous techniques. A new model for grafting enhancement in the presence of the metal salts as well as acids is proposed whereby increased grafting yields are attributed to increased partitioning of monomer into the graft region in the presence of ionic solutes. The value of these additives in preparing copolymers suitable for general reagent insolubilisation reactions is discussed

  14. PRFM enhance wound healing process in skin graft.

    Science.gov (United States)

    Reksodiputro, Mirta; Widodo, Dini; Bashiruddin, Jenny; Siregar, Nurjati; Malik, Safarina

    2014-12-01

    Facial plastic and reconstructive surgery often used skin graft on defects that cannot be covered primarily by a local flap. However, wound healing using skin graft is slow, most of the time the graft is contractured and the take of graft is not optimal. Platelet rich fibrin matrix (PRFM) is a new generation of concentrated platelets that produce natural fibrin and reported to speed up the healing process. Application of PRFM in the skin graft implants is expected to increase the survival of the graft. We used porcine as animal models to elucidate the effect of autologous PRFM on wound healing in full-thickness (FTSG) and split-thickness (STSG) skin grafts. Survival level of the skin graft was determined by using ImageJ software based on the formation of collagen type 1 and graft take. We observed that the use of PRFM in FTSG and STSG increased type 1 collagen formation. We also found that PRFM addition in STSG gave the best skin graft take. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  15. Additive effects in radiation grafting and curing

    International Nuclear Information System (INIS)

    Viengkhou, V.; Ng, L.

    1996-01-01

    Full text: Detailed studies on the accelerative effect of novel additives in radiation grafting and curing using acrylated monomer/oligomer systems have been performed in the presence of ionising radiation and UV as sources. Methyl methacrylate (MMA) is used as typical monomer for these grafting studies in the presence of the additives with model backbone polymers, cellulose and propropylene. Additives which have been found to accelerate these grafting processes are: mineral acid, occlusion compounds like urea, thermal initiators and photoinitiators as well as multifunctional monomers such as multifunctional acrylates. The results from irradiation with gamma rays have also been compared with irradiation from a 90W UV lamp. The role of the above additives in accelerating the analogous process of radiation curing has been investigated. Acrylated urethanes, epoxies and polyesters are used as oligomers together with acrylated monomers in this work with uv lamps of 300 watts/inch as radiation source. In the UV curing process bonding between film and substrate is usually due to physical forces. In the present work the presence of additives are shown to influence the occurrence of concurrent grafting during cure thus affecting the nature of the bonding of the cured film. The conditions under which concurrent grafting with UV can occur will be examined. A mechanism for accelerative effect of these additives in both grafting and curing processes has been proposed involving radiation effects and partitioning phenomena

  16. An unusual case of fistula formation and thrombosis between arteriovenous graft and a native vein

    Directory of Open Access Journals (Sweden)

    Young Sub Kim

    2016-03-01

    Full Text Available Arteriovenous graft for hemodialysis vascular access is a widely used technique with many advantages. However, it has crucial complications with graft thrombosis and infection. We recently experienced an unusual case of arteriovenous graft complication involving graft thrombosis related to fistula formation between the graft and the natural vein with infection. We diagnosed this condition using Doppler ultrasound and computed tomography angiography. Successful surgical treatment including partial graft excision and creation of a secondary arteriovenous fistula using an inadvertently dilated cephalic vein was performed. The dialysis unit staff should keep this condition in mind and try to prevent this complication.

  17. Graft Fibrosis After Pediatric Liver Transplantation : Ten Years of Follow-up

    NARCIS (Netherlands)

    Scheenstra, Rene; Peeters, Paul M. G. J.; Verkade, Henkjan J.; Gouw, Annette S. H.

    Previously we reported the presence of portal fibrosis in 31% (n = 84) of the grafts in protocol biopsies I year after pediatric liver transplantation (LTx). To assess the natural history of graft fibrosis after pediatric liver transplantation, we extended the analysis of graft histology in

  18. GRAFT COPOLYMERIZATION OF OLYGOESTERACRYLATES WITH LIQUID RUBBER AND COPOLYMER’S CHARACTERISTICS

    Directory of Open Access Journals (Sweden)

    Y. A. Anisimov

    2015-02-01

    Full Text Available The kinetic of graft copolymerization of threeethyleneglicoldimethacrylate and di threeethyleneglicolftalatedimethacrylate with liquid buthadiene rubber have been studied as a function of the olygomers composition. The experimental constants of copolymerization rate and efficiency olygoesteracrylates graft to liquid rubber were determined. The ihfluence of olygoesteracrylates’ nature on the grafting efficiency to olygomer rubber is determined and the strength characteristics are found.

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

    Science.gov (United States)

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

    2006-02-01

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

  20. 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.

  1. Synthesis and characterization of fluorinated polyacrylate latex emulsified with novel surfactants.

    Science.gov (United States)

    Zhang, Cuifeng; Xu, Tingting; Bao, Zhongbin; Chen, Lijun

    2017-01-01

    The fluorinated polyacrylate latex were successfully prepared with semi- continuous seeded emulsion polymerization of butyl acrylate (BA), methyl methacrylate (MMA) and hexafluorobutyl methacrylate (HFMA) which was initiated with potassium persulfate (KPS) initiator and emulsified with the novel mixed surfactants of sodium lauryl glutamate (SLG) and alkylphenol ethoxylates (OP-10). The structure of the resultant latex was confirmed by Fourier transform infrared spectroscopy (FTIR). The particle size of the latex was measured by Zetatrac dynamic light scattering detector. The film of latex was tested by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and contact angle (CA). The optimum conditions of preparing the novel fluorinated polyacrylate latex are optimized and the results are as follows: the amount of emulsifiers is 4.0%; mass ratio of SLG to OP-10 is 1:1, the amount of the initiator is 0.6%. The mass ratio of MMA to BA is 1:1 and the amount of HFMA is 7.0%. In this case, the conversion is high and the polymerization stability is good. In addition, the water resistance and thermal properties of the latex films were improved significantly in comparison with the film of the latex prepared without the fluorinated monomer.

  2. Plant latex: a promising antifungal agent for post harvest disease control.

    Science.gov (United States)

    Sibi, G; Wadhavan, Rashmi; Singh, Sneha; Shukla, Abhilasha; Dhananjaya, K; Ravikumar, K R; Mallesha, H

    2013-12-01

    Bioactive compounds from plant latex are potential source of antifungic against post harvest pathogens. Latex from a total of seven plant species was investigated for its phytochemical and antifungal properties. Six fungi namely Aspergillus fumigatus, A. niger, A. terreus, F. solani, P. digitatum and R. arrhizus were isolated from infected fruits and vegetables and tested against various solvent extracts of latex. Analysis of latex extracts with phytochemical tests showed the presence of alkaloids, flavonoids, glycosides, phenols, saponins, steroids, tannins and terpenoids. Antifungal assay revealed the potential inhibitory activity of petroleum ether extracts against the postharvest fungal isolates. Various degree of sensitivity was observed irrespective of plant species studied with A. terreus and P. digitatum as the most susceptible ones. F. solani and A. fumigatus were moderately sensitive to the latex extracts tested. Among the plants, latex of Thevetia peruviana (75.2%) and Artocarpus heterophyllus (64.8%) were having potential antifungal activity against the isolates followed by Manilkara zapota (51.1%). In conclusion, use of plant latex makes interest to control postharvest fungal diseases and is fitting well with the concept of safety for human health and environment.

  3. Aggregation and charging of sulfate and amidine latex particles in the presence of oxyanions.

    Science.gov (United States)

    Sugimoto, Takuya; Cao, Tianchi; Szilagyi, Istvan; Borkovec, Michal; Trefalt, Gregor

    2018-08-15

    Electrophoretic mobility and time resolved light scattering are used to measure the effect on charging and aggregation of amidine and sulfate latex particles of different oxyanions namely, phosphate, arsenate, sulfate, and selenate. In the case of negatively charged sulfate latex particles oxyanions represent the coions, while they represent counterions in the case of the positively charged amidine latex. Repulsive interaction between the sulfate latex surface and the coions results in weak ion specific effects on the charging and aggregation. On the other hand the interaction of oxyanions with the amidine latex surface is highly specific. The monovalent dihydrogen phosphate ion strongly adsorbs to the positively charged surface and reverses the charge of the particle. This charge reversal leads also to the restabilization of the amidine latex suspension at the intermediate phosphate concentrations. In the case of dihydrogen arsenate the adsorption to amidine latex surface is weaker and no charge reversal and restabilization occurs. Similar differences are seen between the sulfate and selenate analogues, where selenate adsorbs more strongly to the surface as compared to the sulfate ion and invokes charge reversal. The present results indicate that ion specificity is much more pronounced in the case of counterions. Copyright © 2018 Elsevier Inc. All rights reserved.

  4. Composite vascular repair grafts via micro-imprinting and electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yuanyuan, E-mail: yuanyuan-liu@shu.edu.cn; Hu, Qingxi, E-mail: huqingxi@shu.edu.cn [Rapid Manufacturing Engineering Center, Shanghai University, Shanghai 200444 (China); Shanghai Key Laboratory of Intelligent Manufacturing and Robotics, Shanghai 200072 (China); Xiang, Ke, E-mail: xiangke@shu.edu.cn; Chen, Haiping, E-mail: 519673062@qq.com; Li, Yu, E-mail: liyu@hpu.edu.cn [Rapid Manufacturing Engineering Center, Shanghai University, Shanghai 200444 (China)

    2015-04-15

    Composite vascular grafts formed by micro-imprinting and electrospinning exhibited improved mechanical properties relative to those formed by electrospinning alone. The three-layered composite grafts mimic the three-layered structure of natural blood vessels. The middle layer is made by micro-imprinting poly-p-dioxanone (PPDO), while the inner and outer layers are electrospun mixtures of chitosan and polyvinyl alcohol. The graft morphology is characterized with scanning electron microscopy. For constant graft thicknesses, the PPDO increases the mechanical strength. Cells cultivated on the vascular grafts adhere and proliferate better because of the natural, biological chitosan in the inner and outer layers. Overall, the composite scaffolds could be good candidates for blood vessel repair.

  5. Nature and structure of aluminum surface sites grafted on silica from a combination of high-field aluminum-27 solid-state NMR spectroscopy and first-principles calculations

    KAUST Repository

    Kerber, Rachel Nathaniel; Kermagoret, Anthony; Callens, Emmanuel; Florian, Pierre A.; Massiot, Dominique; Lesage, Anne; Copé ret, Christophe; Delbecq, Franç oise; Rozanska, Xavier; Sautet, Philippe

    2012-01-01

    The determination of the nature and structure of surface sites after chemical modification of large surface area oxides such as silica is a key point for many applications and challenging from a spectroscopic point of view. This has been, for instance, a long-standing problem for silica reacted with alkylaluminum compounds, a system typically studied as a model for a supported methylaluminoxane and aluminum cocatalyst. While 27Al solid-state NMR spectroscopy would be a method of choice, it has been difficult to apply this technique because of large quadrupolar broadenings. Here, from a combined use of the highest stable field NMR instruments (17.6, 20.0, and 23.5 T) and ultrafast magic angle spinning (>60 kHz), high-quality spectra were obtained, allowing isotropic chemical shifts, quadrupolar couplings, and asymmetric parameters to be extracted. Combined with first-principles calculations, these NMR signatures were then assigned to actual structures of surface aluminum sites. For silica (here SBA-15) reacted with triethylaluminum, the surface sites are in fact mainly dinuclear Al species, grafted on the silica surface via either two terminal or two bridging siloxy ligands. Tetrahedral sites, resulting from the incorporation of Al inside the silica matrix, are also seen as minor species. No evidence for putative tri-coordinated Al atoms has been found. © 2012 American Chemical Society.

  6. Nature and structure of aluminum surface sites grafted on silica from a combination of high-field aluminum-27 solid-state NMR spectroscopy and first-principles calculations

    KAUST Repository

    Kerber, Rachel Nathaniel

    2012-04-18

    The determination of the nature and structure of surface sites after chemical modification of large surface area oxides such as silica is a key point for many applications and challenging from a spectroscopic point of view. This has been, for instance, a long-standing problem for silica reacted with alkylaluminum compounds, a system typically studied as a model for a supported methylaluminoxane and aluminum cocatalyst. While 27Al solid-state NMR spectroscopy would be a method of choice, it has been difficult to apply this technique because of large quadrupolar broadenings. Here, from a combined use of the highest stable field NMR instruments (17.6, 20.0, and 23.5 T) and ultrafast magic angle spinning (>60 kHz), high-quality spectra were obtained, allowing isotropic chemical shifts, quadrupolar couplings, and asymmetric parameters to be extracted. Combined with first-principles calculations, these NMR signatures were then assigned to actual structures of surface aluminum sites. For silica (here SBA-15) reacted with triethylaluminum, the surface sites are in fact mainly dinuclear Al species, grafted on the silica surface via either two terminal or two bridging siloxy ligands. Tetrahedral sites, resulting from the incorporation of Al inside the silica matrix, are also seen as minor species. No evidence for putative tri-coordinated Al atoms has been found. © 2012 American Chemical Society.

  7. Solid state NMR and LVSEM studies on the hardening of latex modified tile mortar systems

    International Nuclear Information System (INIS)

    Rottstegge, J.; Arnold, M.; Herschke, L.; Glasser, G.; Wilhelm, M.; Spiess, H.W.; Hergeth, W.D.

    2005-01-01

    Construction mortars contain a broad variety of both inorganic and organic additives beside the cement powder. Here we present a study of tile mortar systems based on portland cement, quartz, methyl cellulose and different latex additives. As known, the methyl cellulose stabilizes the freshly prepared cement paste, the latex additive enhances final hydrophobicity, flexibility and adhesion. Measurements were performed by solid state nuclear magnetic resonance (NMR) and low voltage scanning electron microscopy (LVSEM) to probe the influence of the latex additives on the hydration, hardening and the final tile mortar properties. While solid state NMR enables monitoring of the bulk composition, scanning electron microscopy affords visualization of particles and textures with respect to their shape and the distribution of the different phases. Within the alkaline cement paste, the poly(vinyl acetate) (VAc)-based latex dispersions stabilized by poly(vinyl alcohol) (PVA) were found to be relatively stable against hydrolysis. The influence of the combined organic additives methyl cellulose, poly(vinyl alcohol) and latexes stabilized by poly(vinyl alcohol) on the final silicate structure of the cement hydration products is small. But even small amounts of additives result in an increased ratio of ettringite to monosulfate within the final hydrated tile mortar as monitored by 27 Al NMR. The latex was found to be adsorbed to the inorganic surfaces, acting as glue to the inorganic components. For similar latex water interfaces built up by poly(vinyl alcohol), a variation in the latex polymer composition results in modified organic textures. In addition to the networks of the inorganic cement and of the latex, there is a weak network build up by thin polymer fibers, most probably originating from poly(vinyl alcohol). Besides the weak network, polymer fibers form well-ordered textures covering inorganic crystals such as portlandite

  8. Comparing the level of dexterity offered by latex and nitrile SafeSkin gloves.

    Science.gov (United States)

    Sawyer, Jo; Bennett, Allan

    2006-04-01

    An increase in the occurrence of latex allergy has been concurrent with the increasing use of latex gloves by laboratory and healthcare workers. In recent years nitrile gloves have been used to replace latex gloves to prevent latex allergy. Nitrile gloves offer a comparable level of protection against chemical and biological agents and are more puncture resistant. However, if manual dexterity is compromised by nitrile gloves to a greater degree than latex then this may increase the risk of sharps injuries. The Purdue pegboard test, which measures both gross and fine finger dexterity, was used to test the dexterity levels of two glove types used at HPA CEPR; Kimberly-Clark SafeSkin nitrile and latex laboratory gloves. There was a statistically significant 8.6% increase in fine finger dexterity provided by latex compared with nitrile SafeSkin laboratory gloves but no difference in gross dexterity between the glove types. There was no significant relationship between glove dexterity and age or gender. The selection of glove size was influenced by the digit length of participants. Moreover, those with longer, thinner fingers appeared to have an advantage when using nitrile SafeSkin gloves. The level of dexterity provided by latex and nitrile SafeSkin gloves for tasks on a gross dexterity level are comparable and health workers will benefit from the non-allergenic properties of nitrile. For tasks requiring fine finger dexterity nitrile SafeSkin gloves may impede dexterity. Despite this, the degree of restriction appears to have a negligible impact on safety in this study when compared with the risk of latex sensitization and subsequent allergy. In addition to glove material, working practices must also take into account glove size, fit, grip and thickness, as these factors can all influence dexterity.

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

    International Nuclear Information System (INIS)

    Allan, M.L.

    1996-06-01

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

  10. 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.

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

    International Nuclear Information System (INIS)

    Eberbeck, Dietmar; Bergemann, Christian; Hartwig, Stefan; Steinhoff, Uwe; Trahms, Lutz

    2005-01-01

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

  12. Optical response of a flat metallic surface coated with a monolayer array of latex spheres

    International Nuclear Information System (INIS)

    Shi Lei; Liu Xiaohan; Yin Haiwei; Zi Jian

    2010-01-01

    We report on the fabrication, characterization and simulation of a structure consisting of a flat metallic surface coated with a monolayer array of latex spheres. This structure shows interesting optical response: over flat metallic surfaces a series of reflection minima appear in reflection spectra. Numerical simulations revealed that the structure can support two types of surface modes: surface plasmon-polaritons bound at the metallic surface and guided modes confined to the array of latex spheres, or their hybrids. Both experimental and theoretical results indicated that these surface modes show well-defined band structures due to the introduced periodicity by the monolayer array of latex spheres.

  13. Validation for radiation sterilization of surgical latex glove

    International Nuclear Information System (INIS)

    Liu Degui

    2002-01-01

    Objective: To determine the optimal radiation mode for sterilization of surgical latex gloves. Methods: The dose distribution in the product loads inside radiation container was measured in different radiation mode. Results: Data of dose distribution in the product load in different radiation mode were obtained. Conclusion: At pre-set height of source working position and within pre-determined dwelling time of each irradiation container staying at the irradiation position, the delivered dose can meet the customers requirement by the radiation mode that, in the half cycle of radiation process, turns the horizontal middle layers of the product to the upper or lower layers, and the upper and lower layers to the middle layers

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

    Directory of Open Access Journals (Sweden)

    Zhi Na

    2013-05-01

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

  15. Infolding of fenestrated endovascular stent graft.

    Science.gov (United States)

    Zelt, Jason G E; Jetty, Prasad; Hadziomerovic, Adnan; Nagpal, Sudhir

    2017-09-01

    We report a case of infolding of a fenestrated stent graft involving the visceral vessel segment after a juxtarenal abdominal aorta aneurysm repair. The patient remains free of any significant endoleak, and the aortic sac has shown regression. The patient remains asymptomatic, with no abdominal pain, with normal renal function, and without ischemic limb complications. We hypothesize that significant graft oversizing (20%-30%) with asymmetric engineering of the diameter-reducing ties may have contributed to the infolding. Because of the patient's asymptomatic nature and general medical comorbidities, further intervention was deemed inappropriate as the aneurysmal sac is regressing despite the infolding.

  16. Biofabrication and testing of a fully cellular nerve graft

    International Nuclear Information System (INIS)

    Owens, Christopher M; Marga, Francoise; Forgacs, Gabor; Heesch, Cheryl M

    2013-01-01

    Rupture of a nerve is a debilitating injury with devastating consequences for the individual's quality of life. The gold standard of repair is the use of an autologous graft to bridge the severed nerve ends. Such repair however involves risks due to secondary surgery at the donor site and may result in morbidity and infection. Thus the clinical approach to repair often involves non-cellular solutions, grafts composed of synthetic or natural materials. Here we report on a novel approach to biofabricate fully biological grafts composed exclusively of cells and cell secreted material. To reproducibly and reliably build such grafts of composite geometry we use bioprinting. We test our grafts in a rat sciatic nerve injury model for both motor and sensory function. In particular we compare the regenerative capacity of the biofabricated grafts with that of autologous grafts and grafts made of hollow collagen tubes by measuring the compound action potential (for motor function) and the change in mean arterial blood pressure as consequence of electrically eliciting the somatic pressor reflex. Our results provide evidence that bioprinting is a promising approach to nerve graft fabrication and as a consequence to nerve regeneration. (paper)

  17. Recent progress on the design and applications of polysaccharide-based graft copolymer hydrogels as adsorbents for wastewater purification

    CSIR Research Space (South Africa)

    Mittal, Hemant

    2016-05-01

    Full Text Available as emulsifiers and thickeners. In their natural form, gum polysaccharides have poor mechanical and physical properties; therefore, they are frequently modified with various synthetic monomers such as acrylamide and acrylic acid using graft copolymerization. Graft...

  18. Latex of amapa (Parahancornia fasciculata (Poir Benoist, Apocynaceae: remedy and income in the forest and in the town

    Directory of Open Access Journals (Sweden)

    Murilo da Serra Silva

    2011-08-01

    Full Text Available The study investigated the production and trade chain as well as aspects of the consumption of the medicinal latex from amapa tree (Parahancornia fasciculata in the municipalities of Belém and Ponta de Pedras, State of Pará, Brazil. Our goal was to shed light upon several aspects related to the management and use of the product, revealing its importance to the life of producers and consumers. The approach used was the 'production to consumption chain' through qualitative and quantitative research methods, including market survey, interviews with extractivists, traders and consumers, workshops, guided visits and forest inventories. The eight thousand litters of milk sold annually in the Belém markets benefit especially the poor people, to whom the use of the 'amapa milk' is secular. The revenue from the latex represents 42% of the total income from non timber forest products for the tappers. The large number of individuals and the J-shaped diameter distribution of trees suggest the possibility of its natural regeneration. The improvement of the tapping technique reveals that the extractivists have knowledge on the tree anatomy. The tradition in the use and management of amapa milk as well as the ecological characteristics of the species indicates a good potential for programs on its sustainable production.

  19. Deposition kinetics of quantum dots and polystyrene latex nanoparticles onto alumina: role of water chemistry and particle coating.

    Science.gov (United States)

    Quevedo, Ivan R; Olsson, Adam L J; Tufenkji, Nathalie

    2013-03-05

    A clear understanding of the factors controlling the deposition behavior of engineered nanoparticles (ENPs), such as quantum dots (QDs), is necessary for predicting their transport and fate in natural subsurface environments and in water filtration processes. A quartz crystal microbalance with dissipation monitoring (QCM-D) was used to study the effect of particle surface coatings and water chemistry on the deposition of commercial QDs onto Al2O3. Two carboxylated QDs (CdSe and CdTe) with different surface coatings were compared with two model nanoparticles: sulfate-functionalized (sPL) and carboxyl-modified (cPL) polystyrene latex. Deposition rates were assessed over a range of ionic strengths (IS) in simple electrolyte (KCl) and in electrolyte supplemented with two organic molecules found in natural waters; namely, humic acid and rhamnolipid. The Al2O3 collector used here is selected to be representative of oxide patches found on the surface of aquifer or filter grains. Deposition studies showed that ENP deposition rates on bare Al2O3 generally decreased with increasing salt concentration, with the exception of the polyacrylic-acid (PAA) coated CdTe QD which exhibited unique deposition behavior due to changes in the conformation of the PAA coating. QD deposition rates on bare Al2O3 were approximately 1 order of magnitude lower than those of the polystyrene latex nanoparticles, likely as a result of steric stabilization imparted by the QD surface coatings. Adsorption of humic acid or rhamnolipid on the Al2O3 surface resulted in charge reversal of the collector and subsequent reduction in the deposition rates of all ENPs. Moreover, the ratio of the two QCM-D output parameters, frequency and dissipation, revealed key structural information of the ENP-collector interface; namely, on bare Al2O3, the latex particles were rigidly attached as compared to the more loosely attached QDs. This study emphasizes the importance of considering the nature of ENP coatings as well

  20. Comparative Proteomics of Rubber Latex Revealed Multiple Protein Species of REF/SRPP Family Respond Diversely to Ethylene Stimulation among Different Rubber Tree Clones

    Directory of Open Access Journals (Sweden)

    Zheng Tong

    2017-05-01

    Full Text Available Rubber elongation factor (REF and small rubber particle protein (SRPP are two key factors for natural rubber biosynthesis. To further understand the roles of these proteins in rubber formation, six different genes for latex abundant REF or SRPP proteins, including REF138,175,258 and SRPP117,204,243, were characterized from Hevea brasiliensis Reyan (RY 7-33-97. Sequence analysis showed that REFs have a variable and long N-terminal, whereas SRPPs have a variable and long C-terminal beyond the REF domain, and REF258 has a β subunit of ATPase in its N-terminal. Through two-dimensional electrophoresis (2-DE, each REF/SRPP protein was separated into multiple protein spots on 2-DE gels, indicating they have multiple protein species. The abundance of REF/SRPP proteins was compared between ethylene and control treatments or among rubber tree clones with different levels of latex productivity by analyzing 2-DE gels. The total abundance of each REF/SRPP protein decreased or changed a little upon ethylene stimulation, whereas the abundance of multiple protein species of the same REF/SRPP changed diversely. Among the three rubber tree clones, the abundance of the protein species also differed significantly. Especially, two protein species of REF175 or REF258 were ethylene-responsive only in the high latex productivity clone RY 8-79 instead of in RY 7-33-97 and PR 107. Some individual protein species were positively related to ethylene stimulation and latex productivity. These results suggested that the specific protein species could be more important than others for rubber production and post-translational modifications might play important roles in rubber biosynthesis.

  1. Evaluation of apparent viscosity of Para rubber latex by diffuse reflection near-infrared spectroscopy.

    Science.gov (United States)

    Sirisomboon, Panmanas; Chowbankrang, Rawiphan; Williams, Phil

    2012-05-01

    Near-infrared spectroscopy in diffuse reflection mode was used to evaluate the apparent viscosity of Para rubber field latex and concentrated latex over the wavelength range of 1100 to 2500 nm, using partial least square regression (PLSR). The model with ten principal components (PCs) developed using the raw spectra accurately predicted the apparent viscosity with correlation coefficient (r), standard error of prediction (SEP), and bias of 0.974, 8.6 cP, and -0.4 cP, respectively. The ratio of the SEP to the standard deviation (RPD) and the ratio of the SEP to the range (RER) for the prediction were 4.4 and 16.7, respectively. Therefore, the model can be used for measurement of the apparent viscosity of field latex and concentrated latex in quality assurance and process control in the factory.

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

    International Nuclear Information System (INIS)

    Healy, Jan; Brennan, Patrick C.; Bowden, Julie Anne

    2003-01-01

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

  3. A LaTeX graphics routine for drawing Feynman diagrams

    International Nuclear Information System (INIS)

    Levine, M.J.S.

    1990-01-01

    FEYNMAN is a LaTeX macropackage which allows the user to construct a versatile range of Feynman diagrams within the text of a document. Diagrams of publication quality may be drawn with relative ease and rapidity. (orig.)

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

    Directory of Open Access Journals (Sweden)

    Davide Bandera

    2016-03-01

    Full Text Available We developed a paper coating for the potential application in food packaging based on polylactide and montmorillonite. It is applied to the paper in the form of a stable, water-based latex with a solid content of 25–28 wt %. The latex is prepared from a commercially available polylactide, surfactants, montmorillonite, a plasticizer, chloroform (to be removed later and water by an emulsion/solvent evaporation procedure. This coating formulation is applied to the paper substrate by bar-coating, followed by hot-pressing at 150 °C. The coated papers achieved up to an 85% improvement in water vapor transmission rates when compared to the pristine papers. 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.

  5. Formation of Defect-Free Latex Films on Porous Fiber Supports

    KAUST Repository

    Lively, Ryan P.; Mysona, Joshua A.; Chance, Ronald R.; Koros, William J.

    2011-01-01

    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

  6. Novel Polyvinyl Alcohol/Styrene Butadiene Rubber Latex/Carboxymethyl Cellulose Nanocomposites Reinforced with Modified Halloysite Nanotubes

    Directory of Open Access Journals (Sweden)

    Yanjun Tang

    2013-01-01

    Full Text Available Novel polyvinyl alcohol (PVA/styrene butadiene rubber (SBR latex/carboxymethyl cellulose (CMC/halloysite nanotubes (HNTs nanocomposites were successfully prepared through physical blending. The as-obtained PVA/SBR/CMC/HNTs nanocomposites were coated on the surface of old corrugated container (OCC-based paper in an effort to improve the mechanical properties of paper. To improve the dispersion of HNTs and enhance the compatibility between HNTs and polymer matrix, HNTs were modified with titanate coupling agent (TCA. FT-IR, together with TGA, confirmed that TCA was grafted onto the surface of HNTs successfully. XRD demonstrated that the crystal structures of HNTs remained almost unchanged. TEM showed that modified HNTs exhibited good dispersion and possessed nanotubular structures with an outer diameter of around 50 nm and an inner diameter of about 20 nm. SEM gave an indication that modified HNTs were dispersed more uniformly than unmodified HNTs within PVA/SBR/CMC matrix. Rheological measurement exhibited that surface modification process enhanced the compatibility between HNTs and polymer matrix, thus resulting in the decreased viscosity of nanocomposites. In comparison with unmodified HNTs, modified HNTs were found to contribute more to the enhancement in mechanical properties, which might be attributed to the better dispersion and compatibility of modified HNTs evidenced by TEM, SEM, and rheological measurement.

  7. Graft-Sparing Strategy for Thoracic Prosthetic Graft Infection.

    Science.gov (United States)

    Uchino, Gaku; Yoshida, Takeshi; Kakii, Bunpachi; Furui, Masato

    2018-04-01

     Thoracic prosthetic graft infection is a rare but serious complication with no standard management. We reported our surgical experience on graft-sparing strategy for thoracic prosthetic graft infection.  This study included patients who underwent graft-sparing surgery for thoracic prosthetic graft infection at Matsubara Tokushukai Hospital in Japan from January 2000 to October 2017.  There were 17 patients included in the analyses, with a mean age at surgery of 71.0 ± 10.5 years; 11 were men. In-hospital mortality was observed in five patients (29.4%).  Graft-sparing surgery for thoracic prosthetic graft infection is an alternative option particularly for early graft infection after hemiarch replacement. Georg Thieme Verlag KG Stuttgart · New York.

  8. Vascularized bone graft in scaphoid fractures. Anatomical details and clinical indications. A cases series

    International Nuclear Information System (INIS)

    Vergara A, Enrique

    2007-01-01

    The fracture of scaphoid continues being a challenge for orthopedist and hand surgeons. Objective. To show the anatomical details of the bony strip from the second metacarpal in corpses injected with green latex and the results of the surgical technique in a series of patients with scaphoid pseudarthrosis. Materials and methods. We carry out an initial anatomical analysis before employing the surgical technique in clinical setting, and then we did a descriptive study of patients with pseudarthrosis of scaphoid,treated with vascularized bony graft by the first metacarpal artery. Results. All patients consolidated and improved in the pain scale, they did not have mobility deterioration or residual carpus instability, after ten years of observations. Conclusions. The vascularized graft is a useful option in the management of the pseudarthrosis of the scaphoid.

  9. Soybean oil in water-borne coatings and latex film formation study by AC impedance

    Science.gov (United States)

    Jiratumnukul, Nantana

    Conventional coalescing agents such as butyl cellosolve, butyl carbitol, and TexanolRTM are widely use in the latex coatings industry to facilitate film formation at ambient temperature. Coalescent aids are composed of solvents with low evaporation rates. After water evaporates, coalescent aids would help soften polymer molecules and form continuous films, then gradually evaporates from the film. Coalescent aids, therefore, are considered as volatile organic compounds (VOC), which are of environmental concern. The main purpose of this research project was to prepare a fatty acid glycol ester from soybean oil and glycol (polyols). The soybean oil glycol ester can be used as a coalescent aid in latex paint formulation. The soybean oil glycol ester not only lowered the minimum film formation temperature of latex polymers and continuous film formed at ambient temperature, but also after it has facilitated film formation, does not substantially evaporate, but becomes part of the film. Soybean oil glycol esters, therefore, can reduce the VOC levels and facilitate film formation of latex paints. In the second part of this research AC-Impedance was used to investigate the efficiency of soybean oil coalescent aid in latex film formation relative to the conventional ones. The coating resistance showed that the efficiency of film formation was increased as a function of dry time. The coating resistance also exhibited the effect of soybean oil ester in latex film formation in the same fashion as a conventional coalescent aid, TexanolRTM.

  10. Use of micrometric latex beads to improve the porosity of hydroxyapatite obtained by chemical coprecipitation method

    Science.gov (United States)

    Webler, G. D.; Rodrigues, W. C.; Silva, A. E. S.; Silva, A. O. S.; Fonseca, E. J. S.; Degenhardt, M. F. S.; Oliveira, C. L. P.; Otubo, L.; Barros Filho, D. A.

    2018-04-01

    Hydroxyapatite is one of the most important biomaterials whose application mainly extends to implants and drug delivery. This work will discuss the changes in the pore size distribution of hydroxyapatite when there are latex beads present during the synthesis. These changes were monitored using different techniques: small angle X-ray scattering, X-ray diffraction, thermal gravimetrical analysis, N2 adsorption, scanning and transmission electron microscopy. Latex beads and hydroxyapatite form a single nanocomposite with well-distinguished inorganic and organic phases. Latex bead removal in the temperature range of 300-600 °C did not modify the original crystalline structure of hydroxyapatite. However, the latex beads favored an increase in the adsorption capacity of mesopores at temperatures higher than their glassy transition (Tg). The main result of this research work consists on the increase of surface area and pore size distribution obtained after the removal of latex beads template. Latex beads have been used in a different approach changing the porosity of hydroxyapatite scaffolds not only introducing new routes for cell integration but also broadening the pore size distribution which can result in a more high efficiency for drug release in living cells.

  11. Preparation of novel film-forming armoured latexes using silica nanoparticles as a pickering emulsion stabiliser.

    Science.gov (United States)

    Shiraz, Hana; Peake, Simon J; Davey, Tim; Cameron, Neil R; Tabor, Rico F

    2018-05-15

    Film-forming polymer latex particles of diameter acrylate (BA) as co-monomers, potassium persulphate (KPS) as an initiator and a commercially available colloidal nano-silica (Ludox®-TM40). It was found that pH control before polymerisation using methacrylic acid (MAA) facilitated the formation of armoured latexes, and mechanistic features of this process are discussed. An alternative, more robust protocol was developed whereby addition of vinyltriethoxysilane (VTES) to control wettability resulted in latexes completely armoured in colloidal nano-silica. The latexes were characterised using SEM, cryo-TEM and AFM imaging techniques. The mechanism behind the adsorption was investigated through surface pressure and contact angle measurements to understand the factors that influence this irreversible adsorption. Results indicate that nanoparticle attachment (but intriguingly not latex size) is dependent on particle wettability, providing new insight into the formation of nanoparticle-armoured latexes, along with opportunities for further development of diversely functionalized inorganic/organic polymer composite particles. Copyright © 2018 Elsevier Inc. All rights reserved.

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

    International Nuclear Information System (INIS)

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

    2015-01-01

    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. (paper)

  13. 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.

  14. 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.

  15. Graft copolymers of polyurethane with various vinyl monomers via radiation-induced miniemulsion polymerization: Influential factors to grafting efficiency and particle morphology

    Energy Technology Data Exchange (ETDEWEB)

    Wang Hua [CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China (USTC), Hefei, Anhui 230026 (China); Wang Mozhen [CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China (USTC), Hefei, Anhui 230026 (China)], E-mail: pstwmz@ustc.edu.cn; Ge Xuewu [CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China (USTC), Hefei, Anhui 230026 (China)], E-mail: xwge@ustc.edu.cn

    2009-02-15

    Graft copolymers of polyurethane (PU) with various vinyl monomers were synthesized through a one-pot but two-step miniemulsion polymerization process. Firstly, the polycondensation of isophorone diisocyanate (IPDI) with hydroxyl-terminated polybutadiene (HTPB) had been performed in aqueous miniemulsion at 40 deg. C in order to obtain PU dispersions. Consecutively, an in-situ graft copolymerization of the vinyl monomers with the synthesized PU was initiated by {gamma}-ray radiation at room temperature. The grafting efficiency of PU with vinyl monomer (G{sub PU/monomer}) was calculated from {sup 1}H NMR spectra and the particle morphology of the final hybrid latex was observed by transmission electron microscopy (TEM). As there was no monomer transferring in miniemulsion system, homogenous hybrid particles would be synthesized provided that the monomer was miscible with PU, such as styrene. With the increase of the polarity of the monomer, the compatibility of PU with monomer decreased. G{sub PU/monomer} varied as G{sub PU/styrene}(37%)>G{sub PU/butyl} {sub acrylate} {sub (BA)}(21%)>G{sub PU/methyl} {sub methacrylate} {sub (MMA)}(12%). The proportion of homogeneous nucleation would increase as the hydrophilicity of the monomer increased. High temperature would destabilize the miniemulsion so as to result in a less grafting efficiency. Compared to the phase separation during the seeded emulsion polymerization, the miniemulsion polymerization method facilitated the preparation of homogeneous materials owing to its monomer droplet nucleation mechanism.

  16. Arteriovenous shunt graft ulceration with sinus and graft epithelialization

    Directory of Open Access Journals (Sweden)

    Pooja Singhal

    2015-03-01

    Full Text Available Arteriovenous fistula and grafts are used as access sites for patients with chronic kidney disease and are prone for complications. Stent grafts are used to treat access site complications. We report a rare and unusual finding of epithelialization of the sinus tract and the lumen of a polytetrafluoroethylene graft, following ulceration of the overlying skin.

  17. natural

    Directory of Open Access Journals (Sweden)

    Elías Gómez Macías

    2006-01-01

    Full Text Available Partiendo de óxido de magnesio comercial se preparó una suspensión acuosa, la cual se secó y calcinó para conferirle estabilidad térmica. El material, tanto fresco como usado, se caracterizó mediante DRX, área superficial BET y SEM-EPMA. El catalizador mostró una matriz de MgO tipo periclasa con CaO en la superficie. Las pruebas de actividad catalítica se efectuaron en lecho fijo empacado con partículas obtenidas mediante prensado, trituración y clasificación del material. El flujo de reactivos consistió en mezclas gas natural-aire por debajo del límite inferior de inflamabilidad. Para diferentes flujos y temperaturas de entrada de la mezcla reactiva, se midieron las concentraciones de CH4, CO2 y CO en los gases de combustión con un analizador de gases tipo infrarrojo no dispersivo (NDIR. Para alcanzar conversión total de metano se requirió aumentar la temperatura de entrada al lecho a medida que se incrementó el flujo de gases reaccionantes. Los resultados obtenidos permiten desarrollar un sistema de combustión catalítica de bajo costo con un material térmicamente estable, que promueva la alta eficiencia en la combustión de gas natural y elimine los problemas de estabilidad, seguridad y de impacto ambiental negativo inherentes a los procesos de combustión térmica convencional.

  18. Effect of wine inhibitors on the proteolytic activity of papain from Carica papaya L. latex.

    Science.gov (United States)

    Benucci, Ilaria; Esti, Marco; Liburdi, Katia

    2015-01-01

    The influence of potential inhibitors naturally present in wine on the proteolytic activity of papain from Carica papaya latex was investigated to evaluate its applicability in white wine protein haze stabilization. Enzymatic activity was tested against a synthetic tripeptide chromogenic substrate in wine-like acidic medium that consisted of tartaric buffer (pH 3.2) supplemented with ethanol, free sulfur dioxide (SO2 ), grape skin and seed tannins within the average ranges of concentrations that are typical in wine. The diagnosis of inhibition type, performed with the graphical method, demonstrated that all of tested wine constituents were reversible inhibitors of papain. The strongest inhibition was exerted by free SO2 , which acted as a mixed-type inhibitor, similar to grape skin and seed tannins. Finally, when tested in table white wines, the catalytic activity of papain, even when if it was ascribable to the hyperbolic behavior of Michaelis-Menten equation, was determined to be strongly affected by free SO2 and total phenol level. © 2014 American Institute of Chemical Engineers.

  19. 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...

  20. Haemodynamics in axillobifemoral bypass grafts

    NARCIS (Netherlands)

    C.H. Wittens

    1992-01-01

    textabstractThis thesis is based on four publications on the subject of graft configuration and haemodynamics in axillobifemoral bypass grafts: 1. A clinical evaluation of 17 patients with axillobifemoral bypass graft operations, performed for various indications. Two important observations were

  1. Primary renal graft thrombosis

    NARCIS (Netherlands)

    Bakir, N; Sluiter, WJ; Ploeg, RJ; van Son, WJ; Tegzess, Adam

    Background. Renal allograft thrombosis is a serious complication of kidney transplantation that ultimately leads to graft loss. Its association with acute and hyperacute rejection is well documented; however, in a large proportion of patients the precise cause remains obscure. The exact incidence

  2. Aortic Graft Infection Secondary to Iatrogenic Transcolonic Graft Malposition.

    Science.gov (United States)

    Blank, Jacqueline J; Rothstein, Abby E; Lee, Cheong Jun; Malinowski, Michael J; Lewis, Brian D; Ridolfi, Timothy J; Otterson, Mary F

    2018-01-01

    Aortic graft infections are a rare but devastating complication of aortic revascularization. Often infections occur due to contamination at the time of surgery. Iatrogenic misplacement of the limbs of an aortobifemoral graft is exceedingly rare, and principles of evaluation and treatment are not well defined. We report 2 cases of aortobifemoral bypass graft malposition through the colon. Case 1 is a 54-year-old male who underwent aortobifemoral bypass grafting for acute limb ischemia. He had previously undergone a partial sigmoid colectomy for diverticulitis. Approximately 6 months after vascular surgery, he presented with an occult graft infection. Preoperative imaging and intraoperative findings were consistent with graft placement through the sigmoid colon. Case 2 is a 60-year-old male who underwent aortobifemoral bypass grafting due to a nonhealing wound after toe amputation. His postoperative course was complicated by pneumonia, bacteremia thought to be secondary to the pneumonia, general malaise, and persistent fevers. Approximately 10 weeks after the vascular surgery, he presented with imaging and intraoperative findings of graft malposition through the cecum. Aortic graft infection is usually caused by surgical contamination and presents as an indolent infection. Case 1 presented as such; Case 2 presented more acutely. Both grafts were iatrogenically misplaced through the colon at the index operation. The patients underwent extra-anatomic bypass and graft explantation and subsequently recovered.

  3. The physicochemical quality and meat microstructure of post laying hen with addition of Biduri (Calotropis gigantea) latex extract

    Science.gov (United States)

    Nuhriawangsa, A. M. P.; Hertanto, B. S.; Kartikasari, L. R.; Swastike, W.; Cahyadi, M.; Rasid, S.

    2018-01-01

    The objective of this study was to evaluate the effect of extract level of Biduri latex on the meat quality of laying hens. The materials of this research were Biduri latex and thigh meat from hens strain Lohman. The latex was tapped from a young tissue stem and centrifuged for its supernatant. Meats were smeared with latex, punctured and incubated for 30 minutes. Concentrations of latex were 0, 3, 6 and 9% from the weight of meat (w/w). The variables were water, dissolved protein, crude fat content, tenderness and microstructure of meat. The statistical analysis method using ANOVA and if there was a mean difference, Duncan test was used. Descriptive analysis was used for microstructures of meat by comparing its hydrolysis conditions. The study showed that fat had significant difference (P meat structure. The fat content increased with addition of 3% latex. The value of dissolved protein increased but tenderness decreased by addition extract of 6% latex. The addition of Biduri latex extract showed that hydrolysis in the microstructure of meat. The addition of 6% latex was the best meat quality.

  4. 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.

  5. Grafting of activated carbon cloths for selective adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Gineys, M.; Benoit, R.; Cohaut, N.; Béguin, F.; Delpeux-Ouldriane, S., E-mail: delpeux@cnrs-orleans.fr

    2016-05-01

    Graphical abstract: - Highlights: • A controlled grafting of carboxylic functions on activated carbon fibers. • The carbon material nanotextural properties preservation after grafting. • An identification of the grafting mechanism through ToF SIMS analysis. • A chemical mapping of the grafted surface using ToF SIMS technique and imaging. - Abstract: Chemical functionalization of an activated carbon cloth with 3-aminophthalic acid and 4-aminobenzoic acid groups by the in situ formation of the corresponding diazonium salt in aqueous acidic solution is reported. The nature and amount of selected functions on an activated carbon surface, in particular the grafted density, were determined by potentiometric titration, elemental analysis and X-ray photoelectron spectroscopy (XPS). The nanotextural properties of the modified carbon were explored by gas adsorption. Functionalized activated carbon cloth was obtained at a discrete grafting level while preserving interesting textural properties and a large porous volume. Finally, the grafting homogeneity of the carbon surface and the nature of the chemical bonding were investigated using Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) technique.

  6. Improving of Water Resistance of Asphalt Concrete Wearing Course Using Latex-Bitumen Binder

    Directory of Open Access Journals (Sweden)

    Siswanto Henri

    2017-01-01

    Full Text Available It is well known that presence of water in a bituminous mix is a critical factor which can lead to premature failure of flexible pavements. This requires solutions one of which is to formulate an asphalt mix that has a high resistance to moisture and one way to do this is to mix latex with the asphalt mix. The purpose of this experimental study was to investigate the effect of water on Marshall stability of asphalt concrete wearing course (ACWC made with a latex-bitumen binder. Latex-bitumen was mixed with aggregate and four levels of latex content were investigated in this study, namely, 0%, 2%, 4% and 6% respectively by weight of asphalt. Wet procces was used in the blending of mixtures. The procedure used to obtain the optimum binder contents conformed to the Marshall procedure (SNI 06-2489-1991. Six Marshall specimens at optimum binder content were prepared for each binder mix investigated. Three of six specimens from each group were tested under Marshall standards. The remaining specimens were tested by immersion in a bath at 60°C for 24 hours. The Marshall index of retained stability was used to evaluate the effect of water on the Marshall stability of ACWC. The results indicated that the addition of up to 4% latex to ACWC mix increased the retained Marshall stability, whereas the addition of latex above 4% decreased the retained stability of the mixture. The addition of 4% CRM significantly improved the retained stability of the mixture and was the best latex – ACWC mix.

  7. 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.

  8. Thermosensitive membranes by radiation-induced graft polymerization of N-isopropyl acrylamide/acrylic acid on polypropylene nonwoven fabric

    International Nuclear Information System (INIS)

    Ikram, Saiqa; Kumari, Mamta; Gupta, Bhuvanesh

    2011-01-01

    Radiation-induced graft copolymerization of N-isopropylacrylamide (NIPAAm) and acrylic acid (AA) mixture was investigated on polypropylene nonwoven fabric to develop a thermosensitive material. The grafting was carried out using methanol, acetone and butanone as homopolymerization inhibitor in the reaction medium. Butanone was observed to give the maximum grafting. It was observed that the grafting is significantly influenced by the reaction conditions, such as radiation dose, monomer concentration, monomer ratio, solvent composition and reaction temperature. The degree of grafting increased as the AA and NIPAAm concentration in the reaction medium increased. The degree of grafting increased as the AA fraction in the NIPAAm/AA mixture increased. The temperature dependence of the grafting process is very much governed by the thermosensitive nature of the grafted chains right from the stage when initial grafting has taken place.

  9. Thermosensitive membranes by radiation-induced graft polymerization of N-isopropyl acrylamide/acrylic acid on polypropylene nonwoven fabric

    Energy Technology Data Exchange (ETDEWEB)

    Ikram, Saiqa; Kumari, Mamta [Department of Chemistry, Jamia Millia Islamia (Central University), New Delhi-110025 (India); Gupta, Bhuvanesh, E-mail: bgupta@textile.iitd.ernet.i [Department of Textile Technology, Indian Institute of Technology, New Delhi-110016 (India)

    2011-01-15

    Radiation-induced graft copolymerization of N-isopropylacrylamide (NIPAAm) and acrylic acid (AA) mixture was investigated on polypropylene nonwoven fabric to develop a thermosensitive material. The grafting was carried out using methanol, acetone and butanone as homopolymerization inhibitor in the reaction medium. Butanone was observed to give the maximum grafting. It was observed that the grafting is significantly influenced by the reaction conditions, such as radiation dose, monomer concentration, monomer ratio, solvent composition and reaction temperature. The degree of grafting increased as the AA and NIPAAm concentration in the reaction medium increased. The degree of grafting increased as the AA fraction in the NIPAAm/AA mixture increased. The temperature dependence of the grafting process is very much governed by the thermosensitive nature of the grafted chains right from the stage when initial grafting has taken place.

  10. Study of Antibacterial Activity and Bacteriology of Latex from Asclepias syriaca L

    Science.gov (United States)

    McCay, Steven; Mahlberg, Paul

    1973-01-01

    Whole and fractionated latex of Asclepias syriaca was tested for antimicrobial or growth-promoting activity with 16 genera and species of bacteria. Latex and extracted fractions (distilled water, acetic acid, sodium bicarbonate, sulfuric acid, and ethyl ether) possessed no detectable antimicrobial activity. Comparison of growth curves of selected bacteria incubated with serum and rubber fractions, as well as controls, revealed no detectable inhibition of growth, except for a slight inhibitory response to autoclaved serum. Most bacteria were capable of utilizing latex for a substrate as indicated by the increased growth rate in the exponential phase. The stationary phase was entered simultaneously by both the treated cultures and the controls. Various bacteria cultured in a litmus latex mixture yielded populations which ranged from <104 organisms/ml for Lactobacillus casei, Staphylococcus aureus and Micrococcus lysodeikticus to 1.1 × 1010 organisms/ml for Clostridium acetobutylicum. Whole latex, as well as the serum and rubber fractions, support the growth of various bacteria, but under field conditions there is no evidence for systemic infection of this type of cell by bacteria. PMID:4790590

  11. Color Spectrum Properties of Pure and Non-Pure LATEX in Discriminating Rubber Clone Series

    International Nuclear Information System (INIS)

    Noor Aishah Khairuzzaman; Hadzli Hashim; Nina Korlina Madzhi; Noor Ezan Abdullah; Faridatul Aima Ismail; Ahmad Faiz Sampian; Azhana Fatnin Che Will

    2015-01-01

    A study of color spectrum properties for pure and non-pure latex in discriminating rubber clone series has been presented in this paper. There were five types of clones from the same series being used as samples in this study named RRIM2002, RRIM2007, RRIM2008, RRIM2014, and RRIM3001. The main objective is to identify the significant color spectrum (RGB) from pure and non-pure latex that can discriminate rubber clone series. The significant information of color spectrum properties for pure and non-pure latex is determined by using spectrometer and Statistical Package for the Social Science (SPSS). Visible light spectrum (VIS) is used as a radiation light of the spectrometer to emit light to the surface of the latex sample. By using SPSS software, the further numerical analysis of color spectrum properties is being conducted. As the conclusion, blue color spectrum for non-pure is able to discriminate for all rubber clone series whereas only certain color spectrum can differentiate several clone series for pure latex. (author)

  12. 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.

  13. Green mediated synthesis and characterization of ZnO nanoparticles using Euphorbia Jatropa latex as reducing agent

    Directory of Open Access Journals (Sweden)

    M.S. Geetha

    2016-09-01

    Full Text Available Presently the progress of green chemistry in the synthesis of nanoparticles with the use of plants has engrossed a great attention. This study reports the synthesis of ZnO using latex of Euphorbia Jatropa as reducing agent. As prepared product was characterized by powder X-ray diffractometer (PXRD, Fourier transform infra-red spectroscopy (FTIR, scanning electron microscopy–energy dispersive spectroscopy (SEM–EDS, transmission electron microscopy (TEM, X-ray photo electron spectroscopy (XPS, Rietveld refinement, UV–Visible spectroscopy and photoluminescence (PL. The concentration of plant latex plays an important role in controlling the size of the particle and its morphology. PXRD graphs showed the well crystallisation of the particles. The average particle size was calculated using Scherrer equation and advanced Williamson Hall (WH plots. The average particle size was around 15 nm. This result was also supported by SEM and TEM analyses. FTIR shows the characteristic peak of ZnO at 435 cm−1. SEM and TEM micrographs show that the particles were almost hexagonal in nature. EDS of SEM analysis confirmed that the elements are only Zn and O. EDS confirmed purity of ZnO. Atomic states were confirmed by XPS results. Crystal parameters were determined using Rietveld refinement. From UV–Visible spectra average energy gap was calculated which is ∼3.63 eV. PL studies showed UV emission peak at 392 nm and broad band visible emission centred in the range 500–600 nm. The Commission International de I'Eclairage and colour correlated temperature coordinates were estimated for ZnO prepared using 2 ml, 4 ml and 6 ml Jatropa latex. The results indicate that the phosphor may be suitable for white light emitting diode (WLED. The study fruitfully reveals simple, fast, economical and eco friendly method of synthesis of multifunctional ZnO nanoparticles (Nps.

  14. 500-Gray γ-Irradiation May Increase Adhesion Strength of Lyophilized Cadaveric Split-Thickness Skin Graft to Wound Bed.

    Science.gov (United States)

    Wei, Lin-Gwei; Chen, Chieh-Feng; Wang, Chi-Hsien; Cheng, Ya-Chen; Li, Chun-Chang; Chiu, Wen-Kuan; Wang, Hsian-Jenn

    2017-03-01

    Human cadaveric skin grafts are considered as the "gold standard" for temporary wound coverage because they provide a more conductive environment for natural wound healing. Lyophilization, packing, and terminal sterilization with gamma-ray can facilitate the application of cadaveric split-thickness skin grafts, but may alter the adhesion properties of the grafts. In a pilot study, we found that 500 Gy γ-irradiation seemed not to reduce the adherence between the grafts and wound beds. We conducted this experiment to compare the adherences of lyophilized, 500-Gy γ-irradiated skin grafts to that of lyophilized, nonirradiated grafts. Pairs of wounds were created over the backs of Sprague- Dawley rats. Pairs of "lyophilized, 500-Gy γ-irradiated" and "lyophilized, nonirradiated" cadaveric split-thickness skin grafts were fixed to the wound beds. Adhesion strength between the grafts and the wound beds was measured and compared. On post-skin-graft day 7 and day 10, the adhesion strength of γ-irradiated grafts was greater than that of the nonirradiated grafts. Because lyophilized cadaveric skin grafts can be vascularized and the collagen of its dermal component can be remodeled after grafting, the superior adhesion strength of 500-Gy γ-irradiated grafts can be explained by the collagen changes from irradiation.

  15. Vein grafting in fingertip replantations.

    Science.gov (United States)

    Yan, Hede; Jackson, William D; Songcharoen, Somjade; Akdemir, Ovunc; Li, Zhijie; Chen, Xinglong; Jiang, Liangfu; Gao, Weiyang

    2009-01-01

    In this retrospective study, the survival rates of fingertip replantation with and without vein grafting were evaluated along with their postoperative functional and cosmetic results. One hundred twenty-one-fingertip amputations were performed in 103 patients between September 2002 and July 2007. Thirty-four amputated fingertips were replanted without vein grafting, while 87 amputated fingertips were replanted with vein grafting for arterial and/or venous repairs. The overall survival rates of the replantations with and without vein grafting were 90% (78/87) and 85% (29/34), respectively. The survival rates were 88% (36/41) with venous repair, 93% (25/27) with arterial repair, and 89% (17/19) with both. Nineteen patients without vein grafting and 48 patients with vein grafting had a follow-up period of more than one year. Good cosmetic and functional outcomes were observed in both groups of patients. The results show that vein grafting is a reliable technique in fingertip replantations, showing no significant difference (P > 0.05) in survival between those with and without vein grafting. Furthermore, no significant difference (P > 0.05) in survival was found between cases with vein grafts for arterial and/or venous repairs. In fingertip replantations with vein grafting, favorable functional and esthetic results can be achieved without sacrificing replantation survival. (c) 2009 Wiley-Liss, Inc.

  16. Improvement of the polymer stability by radiation grafting

    International Nuclear Information System (INIS)

    Ranogajec, F.; Mlinac-Misak, M.

    2004-01-01

    Losses of the stabilizer due to extractability or volatility immediately affect the ultimate performance of polymer products. A new approach to increase the persistence of the stabilizer in the final product is to chemically bind it to the polymer backbone. Radiation grafting or crosslinking could be an efficient method for this, when the stabilizer is polymerizable. By a mutual gamma irradiation method photoprotector 2-hydroxy-4-(3-methacryloxy-2-hydroxy-propoxy) benzophenone has been readily grafted to low-density polyethylene in benzene, tetrahydrofuran and methanol solution, respectively. Surface grafting occurs in a methanol solution of stabilizer, while in benzene and tetrahydrofuran solutions of the stabilizer, grafting proceeds more or less in the inner parts of the polymeric film as well. UV stability tests and changes in the mechanical properties of artificially and naturally aged films indicate pronounced protective effect achieved by the grafted stabilizer. Surface grafting is an efficient photostabilization method since the grafted stabilizer is chemically bound to a polymeric surface and in this way the problem of evaporation of blended stabilizers during the prolonged use of polymeric materials is eliminated

  17. A Review on Grafting of Biofibers for Biocomposites.

    Science.gov (United States)

    Wei, Liqing; McDonald, Armando G

    2016-04-22

    A recent increase in the use of biofibers as low-cost and renewable reinforcement for the polymer biocomposites has been seen globally. Biofibers are classified into: lignocellulosic fibers ( i.e. , cellulose, wood and natural fibers), nanocellulose ( i.e. , cellulose nanocrystals and cellulose nanofibrils), and bacterial cellulose, while polymer matrix materials can be petroleum based or bio-based. Green biocomposites can be produced using both biobased fibers and polymers. Incompatibility between the hydrophilic biofibers and hydrophobic polymer matrix can cause performance failure of resulting biocomposites. Diverse efforts have focused on the modification of biofibers in order to improve the performances of biocomposites. "Grafting" copolymerization strategy can render the advantages of biofiber and impart polymer properties onto it and the performance of biocomposites can be tuned through changing grafting parameters. This review presents a short overview of various "grafting" methods which can be directly or potentially employed to enhance the interaction between biofibers and a polymer matrix for biocomposites. Major grafting techniques, including ring opening polymerization, grafting via coupling agent and free radical induced grafting, have been discussed. Improved properties such as mechanical, thermal, and water resistance have provided grafted biocomposites with new opportunities for applications in specific industries.

  18. Isolation rubber latex binary composites consisting of cotton and poly-N, N-dimethyl-N, N-diallilammony chloride

    Directory of Open Access Journals (Sweden)

    J. Cornejo Tueros

    2012-01-01

    Full Text Available The paper discusses the application of rubber from latex binary coagulating agent consisting of cotton - textile waste and polymeric quaternary ammonium salts. The influence on the process of extracting rubber from latex flow coagulating agent temsperatury and concentration of the dispersed phase.

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

    International Nuclear Information System (INIS)

    Määttänen, Anni; Ihalainen, Petri; Törngren, Björn; Rosqvist, Emil; Pesonen, Markus; Peltonen, Jouko

    2016-01-01

    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_2)_1_1OH (MuOH) thiolation and protein (human serum albumin, HSA) adsorption on the impedance and capacitance was studied. In addition, cyclic voltammetry (CV) measurements were carried out to determine active medicinal components, i.e., caffeic acid with interesting biological activities and poorly water-soluble anti-inflammatory drug, piroxicam. The results show that the fabrication procedure presented in this study enables the formation of platforms with hierarchical morphologies for multimodal (optical and

  20. 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

  1. 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 migh...... 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....

  2. Anticancer activity of flavonol and flavan-3-ol rich extracts from Croton celtidifolius latex.

    Science.gov (United States)

    Biscaro, Fernanda; Parisotto, Eduardo Benedetti; Zanette, Vanilde Citadini; Günther, Tania Mara Fischer; Ferreira, Eduardo Antonio; Gris, Eliana Fortes; Correia, João Francisco Gomes; Pich, Claus Tröger; Mattivi, Fulvio; Filho, Danilo Wilhelm; Pedrosa, Rozangela Curi

    2013-06-01

    Croton celtidifolius Baill (Euphorbiaceae) is a tree found in the Atlantic Forest in Southern Brazil, where it is commonly known as "Sangue-de-Dragão". Its red latex is used traditionally for treating ulcers, diabetes and cancer. To evaluate antitumor activities of Croton celtififolius latex in vitro and in vivo. Phytochemical analyses were conducted using HPLC-DAD-MS. Cytotoxic, nuclease and pro-apoptotic properties were determined using the tetrazolium salt assay (MTT), plasmid DNA damage assay and ethidium bromide (EB)/acridine orange methods, respectively, and antitumor activity was determined in the Ehrlich ascites carcinoma (EAC) mouse model. Phytochemical studies indicated a high phenol content of flavonols (45.67 ± 0.24 and 18.01 ± 0.23 mg/mL of myricetin and quercetin, respectively) and flavan-3-ols (114.12 ± 1.84 and 1527.41 ± 16.42 mg/L of epicatechin and epigallocatechin, respectively) in latex. These compounds reduced MCF-7 and EAC cell viability in the MTT assay (IC50 = 169.0 ± 1.8 and 187.0 ± 2.2 μg/mL, respectively). Latex compounds caused significant DNA fragmentation and increased the number of apoptotic cells (negative control (NC), 12%; latex, 41%) as indicated by differential staining in the EB/acridine orange assay. The in vivo latex treatment at 3.12 mg/kg/day reduced the body weight by 7.57 ± 2.04 g and increased median survival time to 17.5 days when compared to the NC group (13.0 days). In addition, the highest latex concentration inhibited tumor growth by 56%. These results agree with ethno-pharmacological reports showing cytotoxicity and antitumor activity of C. celtidifolius latex. The mechanism of antitumor action may be related to direct DNA fragmentation that reduces survival and induces apoptosis.

  3. Vascular graft infections with Mycoplasma

    DEFF Research Database (Denmark)

    Levi-Mazloum, Niels Donald; Skov Jensen, J; Prag, J

    1995-01-01

    laboratory techniques, the percentage of culture-negative yet grossly infected vascular grafts seems to be increasing and is not adequately explained by the prior use of antibiotics. We have recently reported the first case of aortic graft infection with Mycoplasma. We therefore suggest the hypothesis...... that the large number of culture-negative yet grossly infected vascular grafts may be due to Mycoplasma infection not detected with conventional laboratory technique....

  4. [Immunological mechanisms of graft versus tumor effect].

    Science.gov (United States)

    Ine, Shoji; Yamada, Minami; Miyamura, Koichi; Sasaki, Takeshi

    2003-09-01

    Lesson from hematopoietic stem cell transplantation demonstrated that donor immuno-surveillance system can eradicate tumor cells. This is so-call graft versus tumor(GVT) effect. Antigen presenting cells show peptide from minor antigen rather leukemic specific antigen in the context of major histocompatibility complex. The effector cells composed of CD8 T lymphocyte, CD4 T lymphocyte, natural killer cell and natural killer T cell. Death signal was transmitted from effector cells via granzyme/perforin system and FasL/Fas system, and recently TRAIL system seems most important for GVT effect.

  5. Environmental application of radiation grafting

    International Nuclear Information System (INIS)

    Tamada, Masao

    2007-01-01

    Adsorbent having high selectivity against a certain metal ion was synthesized by means of radiation-induced graft polymerization for the purpose of environmental application. The resulting adsorbents were utilized for the removal of toxic metal from scallop waste and the collection of uranium from seawater. As a novel application of grafting, the biodegradability of poly-hydroxybutylate was controlled by grafting. The biodegradability could be depressed by the graft chain and then recovered by external stimuli such as thermal and chemical treatments. (author)

  6. Grafting the alar rim: application as anatomical graft.

    Science.gov (United States)

    Gruber, Ronald P; Fox, Paige; Peled, Anne; Belek, Kyle A

    2014-12-01

    Alar rim contour and alar rim grafts have become essential components of rhinoplasty. Ideally, grafts of the nose should be anatomical in shape. So doing might make grafts of the alar rim more robust. The authors considered doing that by applying the graft as a continuous extension of the lateral crus. Twelve patients (two men and 10 women) constituted the study group (seven primary and five secondary cases). Of those, there were five concave rims, two concave rims with rim retraction, two boxy tips, and three cephalically oriented lateral crura. Surgical technique included the following: (1) an open approach was used; (2) a marginal incision that ignored the caudal margin of the lateral crus (the incision went straight posteriorly to a point 5 to 6 mm from the rim margin) was used; (3) a triangular graft was made to cover the exposed vestibular skin; (4) it was secured end to end to the caudal border of the lateral crus; and (5) the poster end was allowed to sit in a small subcutaneous pocket. Follow-up was 11 to 19 months. All 12 patients exhibited good rims as judged by a blinded panel. Rim retraction was not fully corrected in one patient, but no further treatment was required. One patient did require a secondary small rim graft for residual rim concavity. The concept of grafting the alar rim is strongly supported by the authors' results. The modifications the authors applied by designing the graft to be anatomical in shape has been a technical help.

  7. Suction blister grafting - Modifications for easy harvesting and grafting

    Directory of Open Access Journals (Sweden)

    2012-01-01

    Full Text Available Suction blister grafting is a simple modality of treatment of patients with resistant and stable vitiligo. But raising the blisters may be time consuming and transferring to the recipient site may be difficult as the graft is ultrathin. By doing some modifications we can make the technique simpler and easier. We can decrease the blister induction time by intradermal injection of saline, exposure to Wood′s lamp, intrablister injection of saline. By these methods we can decrease the blister induction time from 2-3 hrs to 45-90 minutes. After harvesting the graft, it can be transferred to the recipient area by taking the graft on a sterile glass slide, on the gloved finger, rolling the graft over a sterile syringe and then spreading on the recipient area, or taking on the sterile wrapper of paraffin dressing and then placing over the recipient area.

  8. Composite vascular grafts with high cell infiltration by co-electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Zhikai, E-mail: tanzk@hnu.edu.cn; Wang, Hongjie; Gao, Xiangkai; Liu, Tong; Tan, Yongjun

    2016-10-01

    There is an increasing demand for functional small-diameter vascular grafts (diameter < 6 mm) to be used in clinical arterial replacement. An ideal vascular graft should have appropriate biomechanical properties and be biocompatible. Electrospinning has become a popular polymer processing technique for vascular tissue engineering, but the grafts fabricated by electrospinning often have relatively small pores and low porosity, which limit cell infiltration into scaffolds and hinder the regeneration and remodeling of grafts. In the present study, we aimed to develop an efficient method to prepare electrospun composite vascular grafts comprising natural and synthetic materials. We fabricated grafts made of polycaprolactone, gelatin, and polyvinyl alcohol (PVA) by co-electrospinning, and the scaffolds were further functionalized by immobilizing heparin on them. The PVA fibers degraded rapidly in vivo and generated electrospun scaffolds with high porosity, which significantly enhanced cell proliferation and infiltration. The mechanical properties of the grafts are suitable for use in artery replacement. Heparin functionalization of the grafts yielded a good antithrombogenic effect, which was demonstrated in platelet adhesion tests. Moreover, in vitro and in vivo results demonstrated that the heparin release from the grafts enhanced the growth of endothelial cells, which is important for the endothelium of implanted grafts. The results of this study indicate that our method is effective and controllable for the fabrication of vascular grafts that meet the clinical requirements for blood vessel transplantation. - Highlights: • This study indicate an effective method for the fabrication of vascular grafts that meet the clinical requirements. • Co-electrospinning were used to fabricate grafts made of polycaprolactone (PCL), gelatin (GT), and polyvinyl alcohol (PVA). • PVA was used to create large pores within the hybrid scaffolds, thereby enhancing cell infiltration

  9. Composite vascular grafts with high cell infiltration by co-electrospinning

    International Nuclear Information System (INIS)

    Tan, Zhikai; Wang, Hongjie; Gao, Xiangkai; Liu, Tong; Tan, Yongjun

    2016-01-01

    There is an increasing demand for functional small-diameter vascular grafts (diameter < 6 mm) to be used in clinical arterial replacement. An ideal vascular graft should have appropriate biomechanical properties and be biocompatible. Electrospinning has become a popular polymer processing technique for vascular tissue engineering, but the grafts fabricated by electrospinning often have relatively small pores and low porosity, which limit cell infiltration into scaffolds and hinder the regeneration and remodeling of grafts. In the present study, we aimed to develop an efficient method to prepare electrospun composite vascular grafts comprising natural and synthetic materials. We fabricated grafts made of polycaprolactone, gelatin, and polyvinyl alcohol (PVA) by co-electrospinning, and the scaffolds were further functionalized by immobilizing heparin on them. The PVA fibers degraded rapidly in vivo and generated electrospun scaffolds with high porosity, which significantly enhanced cell proliferation and infiltration. The mechanical properties of the grafts are suitable for use in artery replacement. Heparin functionalization of the grafts yielded a good antithrombogenic effect, which was demonstrated in platelet adhesion tests. Moreover, in vitro and in vivo results demonstrated that the heparin release from the grafts enhanced the growth of endothelial cells, which is important for the endothelium of implanted grafts. The results of this study indicate that our method is effective and controllable for the fabrication of vascular grafts that meet the clinical requirements for blood vessel transplantation. - Highlights: • This study indicate an effective method for the fabrication of vascular grafts that meet the clinical requirements. • Co-electrospinning were used to fabricate grafts made of polycaprolactone (PCL), gelatin (GT), and polyvinyl alcohol (PVA). • PVA was used to create large pores within the hybrid scaffolds, thereby enhancing cell infiltration

  10. SOME TECHNIQUES IN CORNEAL GRAFTING

    African Journals Online (AJOL)

    1971-04-10

    Apr 10, 1971 ... current herpes corneae. The visual acuity was less than. 6/60. The left eye had had a central nebula since child- hood and was deemed amblyopic. Six weeks after a 7 x 0·3 mm lamellar graft in the right eye was placed, ulceration occurred in the graft junction. A total thin conjunctival flap was sutured over.

  11. Polyether/Polyester Graft Copolymers

    Science.gov (United States)

    Bell, Vernon L., Jr.; Wakelyn, N.; Stoakley, D. M.; Proctor, K. M.

    1986-01-01

    Higher solvent resistance achieved along with lower melting temperature. New technique provides method of preparing copolymers with polypivalolactone segments grafted onto poly (2,6-dimethyl-phenylene oxide) backbone. Process makes strong materials with improved solvent resistance and crystalline, thermally-reversible crosslinks. Resulting graft copolymers easier to fabricate into useful articles, including thin films, sheets, fibers, foams, laminates, and moldings.

  12. 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.

  13. Reduction of residual monomer in latex products by enhanced polymerization and extraction in supercritical carbon dioxide

    NARCIS (Netherlands)

    Kemmere, M.F.; Schilt, van M.A.; Cleven, M.H.W.; Herk, van A.M.; Keurentjes, J.T.F.

    2002-01-01

    The redn. of Me methacrylate (MMA) in a PMMA latex was chosen as a representative model system. Pulsed electron beam expts. were performed to study the effect of supercrit. carbon dioxide (scCO2) on the monomer concn. inside the polymer particles during the polymn. reaction. The partitioning

  14. 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

  15. 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…

  16. 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

  17. Latex paint as a delivery vehicle for diethylphthalate and di-n-butylphthalate

    DEFF Research Database (Denmark)

    Schripp, Tobias; Salthammer, Tunga; Fauck, Christian

    2014-01-01

    gas-phase concentration at steady state(y). For both, DEP and DnBP, the y0 obtained was lower than the respective saturation vapor pressure (Ps). Furthermore, for both phthalates in latex paint, the material/air partition coefficient (C0/y0) was close in value to the octanol/air partition coefficient...

  18. 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 ...

  19. 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

  20. Lipid transfer protein from Hevea brasiliensis (Hev b 12), a cross-reactive latex protein

    NARCIS (Netherlands)

    Beezhold, Donald H.; Hickey, Vicky L.; Kostyal, David A.; Puhl, Henry; Zuidmeer, Laurian; van Ree, Ronald; Sussman, Gordon L.

    2003-01-01

    BACKGROUND: Latex-allergic individuals experience clinical cross-reactivity to a large number of fruits and vegetables. Much of the cross-reactivity can be attributed to Hev b 6, but evidence indicates that additional cross-reactive allergens may be present. A common pan-allergen, which has not

  1. Adsorption of immunoglobulin G on core-shell latex particles precoated with chaps

    NARCIS (Netherlands)

    Giacomelli, CE; Vermeer, AWP; Norde, W

    2000-01-01

    The aim of this work is to investigate the adsorption behavior of a monoclonal antibody (immunoglobulin G, IgG) on latex particles, possessing reactive chloromethyl groups, precoated with 3-([3-cholamidopropyl]dimethylammonio-1-propansulfonate (Chaps). The amount and reactivity of the surface

  2. Adsorption of immunoglobulin G on core-shell latex particles precoated with chaps

    NARCIS (Netherlands)

    Giacomelli, C.E.; Vermeer, A.W.P.; Norde, W.

    2000-01-01

    The aim of this work is to investigate the adsorption behavior of a monoclonal antibody (immunoglobulin G, IgG) on latex particles, possessing reactive chloromethyl groups, precoated with 3-([3-cholamidopropyl]dimethylammonio-1-propanesulfonate (Chaps). The amount and reactivity of the surface

  3. 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.

  4. 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.

  5. Diagnosis of toxoplasmosis in pregnancy. Evaluation of latex-protein complexes by immnunoagglutination.

    Science.gov (United States)

    Peretti, Leandro E; Gonzalez, Verónica D G; Marcipar, Iván S; Gugliotta, Luis M

    2017-07-01

    The aim of this work was to obtain a reagent based on latex particles for ruling out acute toxoplasmosis in pregnant women by immunoagglutination (IA). Latex-protein complexes (LPC) were previously synthesized coupling the recombinant protein of Toxoplasma gondii P22Ag and the homogenate of the parasite to latex particles with different size, chemical functionality and charge density. LPC were tested in IA assays against a panel of 72 pregnant women serum samples. Results were analysed through receiver operating characteristic curves, determining area under the curve (AUC), sensitivity, specificity positive and negative predictive values (PPV and NPV, respectively). It was observed that the antigenicity of proteins was not affected during sensitization by either physical adsorption or covalent coupling. The best results in the sense of maximizing discrimination of low avidity sera from chronic ones were observed for the IA test based on latex particles with carboxyl functionality and the recombinant P22Ag, obtaining an AUC of 0·94, a sensitivity of 100% and a NPV of 100%. In this way, the proposed test could be useful for the toxoplasmosis diagnosis in pregnant women, with the advantages of being cheap, rapid and easy to be implemented.

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

    KAUST Repository

    Lone, Saifullah; Vakarelski, Ivan Uriev; Chew, Basil; Wang, Zhihong; Thoroddsen, Sigurdur T

    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

  7. Dynamics of ballistically injected latex particles in living human endothelial cells

    NARCIS (Netherlands)

    Li, Y.; Vanapalli Veera, V.S.A.R.; Vanapalli, Srinivas; Duits, Michael H.G.

    2009-01-01

    We studied the dynamics of ballistically injected latex particles (BIP) inside endothelial cells, using video particle tracking to measure the mean squared displacement (MSD) as a function of lag time. The MSD shows a plateau at short times and a linear behavior at longer times, indicating that the

  8. 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.

  9. [Detection of anti-Leptospira antibodies in sera of patients in the latex agglutination test].

    Science.gov (United States)

    Volina, E G; Sarukhanova, L E; Iashina, N V; Prokopov, N I; Shkarlat, P E; Barysheva, I V

    2001-01-01

    The results of the preliminary evaluation of the sensitivity and specificity of the newly developed diagnostic test based on the determination of genus-specific antibodies to leptospires in the latex agglutination test, are presented. This test makes it possible to detect anti-Leptospira antibodies of any serogroup. The advantages of the developed test have been determined.

  10. 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

  11. The study of the use of a latex biomembrane and conjunctival autograft in rabbit conjunctiva wound healing.

    Science.gov (United States)

    Pinho, Erika Christina Canarim Martha de; Chahud, Fernando; Lachat, João-José; Coutinho-Netto, Joaquim José; Sousa, Sidney Julio Faria E

    2018-04-01

    removed from the superonasal quadrant adjacent to the limbus in both eyes. The bare area of the sclerotic coat of the right eye was reconstructed with a latex biomembrane, and the corresponding site of the left eye was reconstructed with a conjunctival autograft. The animals were killed in groups of three at 7, 14, and 21 days after surgery. The tissues from the surgical site, including the cornea, were fixed in formaldehyde, and were then processed in paraffin and stained with hematoxylin and eosin. The nature and intensity of the inflammatory response and the epithelial pattern at the conjunctival surface were evaluated under optical microscopy with longitudinal histological sections through the center of the anatomical specimens. Until the 14th postoperative day, the inflammatory reaction was greater in the biomembrane group than in the conjunctival autograft group. In the latex biomembrane group, inflammation was less intense and the stroma was thicker on the 14th postoperative day than on the 7th postoperative day. After three weeks, conjunctival healing in both groups showed similar characteristics. Although healing was slower with a latex biomembrane, tissue reconstitution was almost the same as that with a conjunctival autograft by three weeks. A latex biomembrane is as effective as a conjunctival autograft for the reconstruction of the ocular surface. Owing to the lack of toxicity and allergenicity, a latex biomembrane appears to be a promising therapeutic option for conjunctival reconstruction.

  12. CT findings in ten patients with failed renal allografts: comparison with findings in functional grafts

    International Nuclear Information System (INIS)

    Gayer, Gabriela; Apter, Sara; Katz, Rama; Ben-David, Aharon; Katzir, Ze'ev; Hertz, Marjorie

    2000-01-01

    Our aim is to report the computed tomography (CT) features of the long-term failed renal allograft. Ten patients with failed renal transplants in whom the graft was left in situ underwent CT for various unrelated indications. The majority of the failed grafts showed marked shrinkage and coarse punctate diffuse parenchymal calcifications. Small cysts were seen in four grafts. A long-term failed renal transplant appeared on CT as a small rounded soft tissue mass. The graft was almost always heavily calcified. Lack of awareness of the nature of such a mass may mislead the radiologist in interpreting it as a space-occupying lesion

  13. Honey: A Skin Graft Fixator Convenient for Both Patient and Surgeon.

    Science.gov (United States)

    Maghsoudi, Hemmat; Moradi, Sohrab

    2015-12-01

    Skin grafts can be used effectively to cover burn injuries. A critical element of this treatment is the adherence of the graft to the wound bed. Honey has been shown to increase the adherence of skin grafts to wound beds and have antibacterial and anti-inflammatory effects and increase healing rate of wounds. We therefore devised a clinical trial to determine the effect of honey on skin graft fixation in burn injuries. Sixty patients were included in this study (in 30 patients, graft was fixed with medical honey, and in 30 patients, it was fixed with dressing or suturing). All patients in two groups were evaluated for infection, graft loss, graft contraction, severity of pain, and need for re-operation. The most common cause of burn was kerosene. Honey significantly decreased infection rate on fifth day and reduced the patient pain. The mean hospital stay was shorter in honey group. Contraction of graft was significantly less in honey group. Honey has strong adhesive properties for skin graft fixation. Medical honey is a natural material, not synthetic. For this reason, we can advise the application of medical honey for the fixation of split thickness skin graft.

  14. Electrospun polydioxanone-elastin blends: potential for bioresorbable vascular grafts

    Energy Technology Data Exchange (ETDEWEB)

    Sell, S A [Virginia Commonwealth University, Richmond, VA 23298 (United States); McClure, M J [Virginia Commonwealth University, Richmond, VA 23298 (United States); Barnes, C P [Virginia Commonwealth University, Richmond, VA 23298 (United States); Knapp, D C [Virginia Commonwealth University, Richmond, VA 23298 (United States); Walpoth, B H [University Hospital, 1211 Geneva 14 (Switzerland); Simpson, D G [Virginia Commonwealth University, Richmond, VA 23298 (United States); Bowlin, G L [Virginia Commonwealth University, Richmond, VA 23298 (United States)

    2006-06-15

    An electrospun cardiovascular graft composed of polydioxanone (PDO) and elastin has been designed and fabricated with mechanical properties to more closely match those of native arterial tissue, while remaining conducive to tissue regeneration. PDO was chosen to provide mechanical integrity to the prosthetic, while elastin provides elasticity and bioactivity (to promote regeneration in vitro/in situ). It is the elastic nature of elastin that dominates the low-strain mechanical response of the vessel to blood flow and prevents pulsatile energy from being dissipated as heat. Uniaxial tensile and suture retention tests were performed on the electrospun grafts to demonstrate the similarities of the mechanical properties between the grafts and native vessel. Dynamic compliance measurements produced values that ranged from 1.2 to 5.6%/100 mmHg for a set of three different mean arterial pressures. Results showed the 50:50 ratio to closely mimic the compliance of native femoral artery, while grafts that contained less elastin exceeded the suture retention strength of native vessel. Preliminary cell culture studies showed the elastin-containing grafts to be bioactive as cells migrated through their full thickness within 7 days, but failed to migrate into pure PDO scaffolds. Electrospinning of the PDO and elastin-blended composite into a conduit for use as a small diameter vascular graft has extreme potential and warrants further investigation as it thus far compares favorably to native vessel.

  15. Graft intolerance syndrome requiring graft nephrectomy after late kidney graft failure: can it be predicted? A retrospective cohort study.

    Science.gov (United States)

    Bunthof, Kim L W; Verhoeks, Carmen M; van den Brand, Jan A J G; Hilbrands, Luuk B

    2018-02-01

    Graft nephrectomy is recommended in case of early graft failure. When the graft fails more than 3-6 months after transplantation, it is current practice to follow a wait-and-see policy. A common indication for graft removal is the graft intolerance syndrome. We aimed to create a risk prediction model for the occurrence of graft intolerance resulting in graft nephrectomy. We collected data of kidney transplantations performed in our center between 1980 and 2010 that failed at least 6 months after transplantation. We evaluated the association between baseline characteristics and the occurrence of graft nephrectomy because of graft intolerance using a competing risk regression model. Prognostic factors were included in a multivariate prediction model. In- and exclusion criteria were met in 288 cases. In 48 patients, the graft was removed because of graft intolerance. Donor age, the number of rejections, and shorter graft survival were predictive factors for graft nephrectomy because of the graft intolerance syndrome. These factors were included in a prediction rule. Using donor age, graft survival, and the number of rejections, clinicians can predict the need for graft nephrectomy with a reasonable accuracy. © 2017 Steunstichting ESOT.

  16. Proceedings of the Second International Symposium on RVNRL (Radiation Vulcanisation of Natural Rubber Latex)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    This book compiled the papers presented at this symposium. The papers discussed were categorized under i. preparation and properties of RVNRL, ii. characterisation and advantages of RVNRL, iii. scale up preparations and applications, iv. RVNRL pilot plant design and operation, and v. property improvement in RVNRL products,

  17. Proceedings of the Second International Symposium on RVNRL (Radiation Vulcanisation of Natural Rubber Latex)

    International Nuclear Information System (INIS)

    1996-01-01

    This book compiled the papers presented at this symposium. The papers discussed were categorized under i. preparation and properties of RVNRL, ii. characterisation and advantages of RVNRL, iii. scale up preparations and applications, iv. RVNRL pilot plant design and operation, and v. property improvement in RVNRL products,

  18. 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

    patients prick tested for NRL at the Department of Dermatology and Allergy Centre, Odense University Hospital were included in this study (n = 8580). In NRL-sensitized patients, the clinical relevance was evaluated for NRL. Furthermore, concomitant positive prick test results for birch pollen were recorded.......5-0.6% in 2006-2013 (p history of reaction to oral intake of related fruits or vegetables. CONCLUSION: Our study showed a statistically significant decline in the number of patients...

  19. Physicomechanical properties of nanocomposites based on cellulose nanofibre and natural rubber latex

    CSIR Research Space (South Africa)

    Abraham, E

    2012-11-01

    Full Text Available and tensile strength was observed as a result of addition of CNF to the rubber matrix especially at higher CNF loading. DMA showed a change in the storage modulus of the rubber matrix upon addition of CNF which proves the reinforcing effect of CNF in the NR...

  20. Caracterização da hipersensibilidade a luvas de látex em profissionais da odontologia - DOI: 10.4025/actascihealthsci.v29i1.103 Rubber latex gloves hypersensitivities in dental workers - DOI: 10.4025/actascihealthsci.v29i1.103

    Directory of Open Access Journals (Sweden)

    Ana Maria Sell

    2007-12-01

    Full Text Available As reações alérgicas ao látex vêm aumentando em profissionais da saúde e se manifestam como um incômodo local ou sintomatologia sistêmica. Para conhecer a freqüência das manifestações alérgicas nos usuários de luvas de látex foi realizada busca entre os profissionais da odontologia via aplicação de questionários. Foram aplicados 450 questionários e, dentre os respondedores (140, 19% relataram manifestar reações locais ao contato com as luvas de látex e 5% reações sistêmicas a outros produtos de látex. Cerca de 2,5% declararam dermatite de contato e reações sistêmicas (anafiláticas, 1,5% apenas dermatite de contato e 1% sintomas de anafilaxia ao uso das luvas. Vinte por cento dos profissionais atenderam pacientes com alergia ao látex e 29% declararam questionar, durante a anamnese, a respeito de alergia ao látex. As reações alérgicas a luvas de látex foram freqüentes e é objeto de preocupação entre os profissionais da odontologia.Allergic reactions to natural rubber latex have increased in dental practice affecting both the professional and the patients. Allergic reactions may range from skin disease to asthma and anaphylaxis. This study aimed at determining the incidence of latex gloves allergy among dental care workers. 450 allergy questionnaires were used to collect information on latex gloves reactions and 140 dental works answered them. Latex gloves reaction occurred in 19% of them and 5% reported allergic reactions to other latex products. 2.5% reported symptoms suggesting contact dermatitis and anaphylaxis hypersensitivities, 1.5% contact dermatitis, and 1% reported anaphylaxis symptoms when wearing them. 20% of them had patients who presented symptoms suggestive of anaphylaxis hypersensitivity to rubber gloves latex. Our study confirms that rubber latex gloves reactions are frequent among dental care workers, and dentists must be aware of the latex allergy in dental practice.

  1. Cartilage grafting in nasal reconstruction.

    Science.gov (United States)

    Immerman, Sara; White, W Matthew; Constantinides, Minas

    2011-02-01

    Nasal reconstruction after resection for cutaneous malignancies poses a unique challenge to facial plastic surgeons. The nose, a unique 3-D structure, not only must remain functional but also be aesthetically pleasing to patients. A complete understanding of all the layers of the nose and knowledge of available cartilage grafting material is necessary. Autogenous material, namely septal, auricular, and costal cartilage, is the most favored material in a free cartilage graft or a composite cartilage graft. All types of material have advantages and disadvantages that should guide the most appropriate selection to maximize the functional and cosmetic outcomes for patients. Copyright © 2011 Elsevier Inc. All rights reserved.

  2. Inheritance of graft compatibility in Douglas fir.

    Science.gov (United States)

    D.L. Copes

    1973-01-01

    Graft compatibility of genetically related and unrelated rootstock-scion combinations was compared. Scion clones were 75% compatible when grafted on half-related rootstocks but only 56% compatible when grafted on unrelated rootstocks. Most variance associated with graft incompatibility in Douglas-fir appears to be caused by multiple genes.

  3. Graft union formation in Douglas-fir.

    Science.gov (United States)

    D.L. Copes

    1969-01-01

    Greenhouse-grown Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) graft unions were examined between 2 and 84 days after grafting. Room temperature was maintained at 60-70 F throughout the growing season. In most respects grafts of Douglas-fir followed development patterns previously reported for spruce and pine grafts, but specific differences...

  4. Reinforcement of Natural Rubber with Core-Shell Structure Silica-Poly(Methyl Methacrylate Nanoparticles

    Directory of Open Access Journals (Sweden)

    Qinghuang Wang

    2012-01-01

    Full Text Available A highly performing natural rubber/silica (NR/SiO2 nanocomposite with a SiO2 loading of 2 wt% was prepared by combining similar dissolve mutually theory with latex compounding techniques. Before polymerization, double bonds were introduced onto the surface of the SiO2 particles with the silane-coupling agent. The core-shell structure silica-poly(methyl methacrylate, SiO2-PMMA, nanoparticles were formed by grafting polymerization of MMA on the surface of the modified SiO2 particles via in situ emulsion, and then NR/SiO2 nanocomposite was prepared by blending SiO2-PMMA and PMMA-modified NR (NR-PMMA. The Fourier transform infrared spectroscopy results show that PMMA has been successfully introduced onto the surface of SiO2, which can be well dispersed in NR matrix and present good interfacial adhesion with NR phase. Compared with those of pure NR, the thermal resistance and tensile properties of NR/SiO2 nanocomposite are significantly improved.

  5. Breast Reconstruction after a Bilateral Mastectomy Using the BRAVA Expansion System and Fat Grafting

    Directory of Open Access Journals (Sweden)

    Ondrej Mestak, MD

    2013-11-01

    Full Text Available Summary: Fat graft breast reconstruction following a mastectomy is always limited by the size of the skin envelope, which affects the amount of graft that can be injected in 1 session. Because the fat graft naturally resorbs in all patients, several sessions of fat grafting are necessary. BRAVA’s negative pressure causes a “reverse” expansion of the skin envelope, thus permitting more space for the fat graft. This allows decreasing number of required procedures for an adequate breast reconstruction. We operated on a 38-year-old patient 4 years after bilateral mastectomy without irradiation for breast cancer. Before the procedure, the patient was instructed to wear the BRAVA system for 12 hours daily for 2 months before the first session, at all times between the sessions and for 1 month following the last fat grafting session. We performed 3 fat grafting sessions, as planned. Altogether, we injected 840 cm3 of fat on the right side and 790 cm3 of fat on the left side. Four months after the last operation, the patient was very satisfied with her new breasts. The breasts were soft, with good sensation and a natural feel. Using the BRAVA external expansion system for the enhancement of fat grafting is a suitable technique for breast reconstruction after a mastectomy. This technique produces soft and natural feeling breasts in fewer operative sessions, with a minimal risk of complications. Patient compliance, however, is greatly needed to achieve the desired results.

  6. Fat Grafting for Facial Filling and Regeneration.

    Science.gov (United States)

    Coleman, Sydney R; Katzel, Evan B

    2015-07-01

    Plastic surgeons have come to realize that fat grafting can rejuvenate an aging face by restoring or creating fullness. However, fat grafting does much more than simply add volume. Grafted fat can transform or repair the tissues into which it is placed. Historically, surgeons have hesitated to embrace the rejuvenating potential of fat grafting because of poor graft take, fat necrosis, and inconsistent outcomes. This article describes fat grafting techniques and practices to assist readers in successful harvesting, processing, and placement of fat for optimal graft retention and facial esthetic outcomes. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Design of a Sapling Branch Grafting Robot

    Directory of Open Access Journals (Sweden)

    Qun Sun

    2014-01-01

    Full Text Available The automatic sapling grafting methods and grafting robot technologies are not comprehensively studied despite the fact that they are urgently required in practice. For this reason, a sapling grafting robot is developed to implement automatic grafting for saplings. The developed grafting robot includes clipping mechanism, moving mechanism, cutting mechanism, binding mechanism, and Arduino MCU based control system, which is capable of clipping, moving, positioning, cutting, grafting, and binding saplings. Experiments show that the stock cutting efficiency is 98.4%, the scion cutting efficiency is 98.9%, the grafting efficiency is 87.3%, and the binding efficiency is 68.9%.

  8. 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.

  9. Hydrophilic/hydrophobic character of grafted cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Takacs, E., E-mail: takacs@iki.kfki.h [Institute of Isotopes, Hungarian Academy of Sciences, Budapest (Hungary); Wojnarovits, L. [Institute of Isotopes, Hungarian Academy of Sciences, Budapest (Hungary); Borsa, J. [Budapest University of Technology and Economics (Hungary); Racz, I. [Bay Zoltan Institute for Materials Science and Technology, Budapest (Hungary)

    2010-04-15

    Vinyl monomers with long paraffin chains were grafted onto two kinds of cellulose (cotton and cotton linter) by direct irradiation grafting technique. The effect of dose, monomer structure and concentration, as well as homopolymer suppressor (styrene) concentration on the grafting yield was studied and the optimal grafting conditions were established. Grafting decreased the swelling of the samples in water and increased their polymer compatibility in polypropylene matrix.

  10. Air Pump-Assisted Graft Centration, Graft Edge Unfolding, and Graft Uncreasing in Young Donor Graft Pre-Descemet Endothelial Keratoplasty.

    Science.gov (United States)

    Jacob, Soosan; Narasimhan, Smita; Agarwal, Amar; Agarwal, Athiya; A I, Saijimol

    2017-08-01

    To assess an air pump-assisted technique for graft centration, graft edge unfolding, and graft uncreasing while performing pre-Descemet endothelial keratoplasty (PDEK) using young donor grafts. Continuous pressurized air infusion was used for graft centration, graft edge unfolding, and graft unwrinkling. Ten eyes of 10 patients underwent PDEK with donors aged below 40 years. In all eyes, the donor scrolled into tight scrolls. In all cases, the air pump-assisted technique was effective in positioning and centering the graft accurately and in straightening infolded graft edges and smoothing out graft creases and wrinkles. Endothelial cell loss was 38.6%. Postoperative best-corrected visual acuity at 6 months was 0.66 ± 0.25 in decimal equivalent. Continuous pressurized air infusion acted as a third hand providing a continuous pressure head that supported the graft and prevented graft dislocation as well as anterior chamber collapse during intraocular maneuvering. Adequate maneuvering space was available in all cases, and bleeding, if any, was tamponaded successfully in all cases. Although very young donor grafts may be used for PDEK, they are difficult to center and unroll completely before floating against host stroma. An air pump-assisted technique using continuous pressurized air infusion allows successful final graft positioning even with very young donor corneas. It thus makes surgery easier as several key steps are made easier to handle. It additionally helps in tamponading hemorrhage during peripheral iridectomy, increasing surgical space, preventing fluctuations in the anterior chamber depth, and promoting graft adherence.

  11. 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.

  12. Frequent IgE sensitization to latex, cow's milk, and egg in children with short bowel syndrome.

    Science.gov (United States)

    Mazon, Angel; Solera, Eva; Alentado, Noemi; Oliver, Fernando; Pamies, Rafael; Caballero, Luis; Nieto, Antonio; Dalmau, Jaime

    2008-03-01

    Children with short bowel syndrome (SBS) undergo frequent operations, so they are at risk for sensitizing to latex. There have been isolated reports of sensitization to food in these children. In a cross-sectional study, we assessed sensitization to latex, cow's milk, and egg with skin prick tests (SPT) and serum-specific immunoglobulin E (IgE) in 14 children with SBS. Data were collected about the number of operations with latex devices, serum total IgE, and history of feeding with milk formula. Ten children were sensitized to latex (specific IgE median: 6.7 kU/l, range: 0.5-33). Compared with those non-sensitized, sensitized children had significantly (p range: 0.5-21.1 kU/l), and five to egg (specific IgE median: 0.68, range: 0.58-2.17 kU/l). Except for some isolated days with cow's milk formula, the children had been initially fed with a diet without intact cow's milk proteins. Sensitization to latex, cow's milk, and egg is very frequent in children with SBS. They should be treated in a latex-free environment since the very early stages of the disease, and should be routinely studied regarding food sensitization, as this might contribute as an added factor in the chronic diarrhea of these patients.

  13. FAS grafted superhydrophobic ceramic membrane

    Energy Technology Data Exchange (ETDEWEB)

    Lu Jun [School of Material Science and Engineering, Jingdezhen Ceramic Institute, 333001 Jingdezhen (China); Key Laboratory of Inorganic Coating Materials, Shanghai Institute of Ceramics, CAS, 1295 DingXi Road, Shanghai 200050 (China); Yu Yun, E-mail: yunyush@mail.sic.ac.cn [Key Laboratory of Inorganic Coating Materials, Shanghai Institute of Ceramics, CAS, 1295 DingXi Road, Shanghai 200050 (China); Zhou Jianer [School of Material Science and Engineering, Jingdezhen Ceramic Institute, 333001 Jingdezhen (China); Song Lixin; Hu Xingfang [Key Laboratory of Inorganic Coating Materials, Shanghai Institute of Ceramics, CAS, 1295 DingXi Road, Shanghai 200050 (China); Larbot, Andre [Institut Europeen des Membranes, UMR 5635-CNRS, ENSCM, UMII, 1919 Route de Mende 34293, Montpellier Cedex 5 (France)

    2009-08-30

    The hydrophobic properties of {gamma}-Al{sub 2}O{sub 3} membrane have been obtained by grafting fluoroalkylsilane (FAS) on the surface of the membrane. The following grafting parameters were studied: the eroding time of the original membrane, the grafting time, the concentration of FAS solution and the multiplicity of grafting. Hydrophobicity of the membranes was characterized by contact angle (CA) measurement. The thermogravimetric analysis (TGA) was used to investigate the weight loss process (25-800 deg. C) of the fluoroalkylsilane grafted on Al{sub 2}O{sub 3} powders under different grafting conditions. The morphologies of the membranes modified under different parameters were examined by field emission scanning electron microscopy (FE-SEM) and the surface roughness (Ra) was measured using white light interferometers. A needle-like structure was observed on the membrane surface after modification, which causes the change of Ra. On the results above, we speculated a model to describe the reaction between FAS and {gamma}-Al{sub 2}O{sub 3} membrane surface as well as the formed surface morphology.

  14. FAS grafted superhydrophobic ceramic membrane

    Science.gov (United States)

    Lu, Jun; Yu, Yun; Zhou, Jianer; Song, Lixin; Hu, Xingfang; Larbot, Andre

    2009-08-01

    The hydrophobic properties of γ-Al 2O 3 membrane have been obtained by grafting fluoroalkylsilane (FAS) on the surface of the membrane. The following grafting parameters were studied: the eroding time of the original membrane, the grafting time, the concentration of FAS solution and the multiplicity of grafting. Hydrophobicity of the membranes was characterized by contact angle (CA) measurement. The thermogravimetric analysis (TGA) was used to investigate the weight loss process (25-800 °C) of the fluoroalkylsilane grafted on Al 2O 3 powders under different grafting conditions. The morphologies of the membranes modified under different parameters were examined by field emission scanning electron microscopy (FE-SEM) and the surface roughness (Ra) was measured using white light interferometers. A needle-like structure was observed on the membrane surface after modification, which causes the change of Ra. On the results above, we speculated a model to describe the reaction between FAS and γ-Al 2O 3 membrane surface as well as the formed surface morphology.

  15. Interventions in Infrainguinal Bypass Grafts

    International Nuclear Information System (INIS)

    Mueller-Huelsbeck, S.; Order, B.-M.; Jahnke, T.

    2006-01-01

    The interventional radiologist plays an important role in the detection and prevention of infrainguinal bypass failure. Early detection and evaluation of flow-limiting lesions effectively preserve graft (venous bypass and polyester or expanded polytetrafluoroethylene bypass) patency by identifying stenoses before occlusion occurs. Delay in treatment of the at-risk graft may result in graft failure and a reduced chance of successful revascularization. For this reason, surveillance protocols form an important part of follow-up after infrainguinal bypass surgery. As well as having an understanding of the application of imaging techniques including ultrasound, MR angiography, CT angiography and digital subtraction angiography, the interventional radiologist should have detailed knowledge of the minimally invasive therapeutic options. Percutaneous transluminal angioplasty (PTA), or alternatively cutting balloon angioplasty, is the interventional treatment of choice in prevention of graft failure and occlusion. Further alternatives include metallic stent placement, fibrinolysis, and mechanical thrombectomy. Primary assisted patency rates following PTA can be up to 65% at 5 years. When the endovascular approach is unsuccessful, these therapeutic options are complemented by surgical procedures including vein patch revision, jump grafting, or placement of a new graft

  16. EVALUATION OF CYTOTOXIC, ANTIMICROBIAL AND ANTIINFLAMMATORY PROPERTIES FROM THE LATEX OF IPOMEA STAPHYLINA

    Directory of Open Access Journals (Sweden)

    Prasanthi Narra

    2014-04-01

    Full Text Available The plant Ipomoea staphylina has been used in diverse traditional medication for the treatment of diseases and illness of human beings. The crude latex extract obtained from the stem of Ipomea staphylina was evaluated for cytotoxic, antimicrobial and wound healing properties. Cell viability and cytotoxicity assays such as Colony Formation method and Enzyme based methods that determined cell viability with a colorimetric method were performed to evaluate the medicinal properties of Ipomea staphylina. Similarly Microbiological Antibiotic Assay to determine the antimicrobial properties and wound healing properties were tested by determining the potent anti-inflammatory molecules that inhibited COX and LOX enzymes. Results showed that the latex crude extract of Ipomea staphylina showed potent Antimicrobial and Antiinflamatory properties, but the viability of the cells were unaffected.

  17. Tensile properties of latex paint films with TiO2 pigment

    Science.gov (United States)

    Hagan, Eric W. S.; Charalambides, Maria N.; Young, Christina T.; Learner, Thomas J. S.; Hackney, Stephen

    2009-05-01

    The tensile properties of latex paint films containing TiO2 pigment were studied with respect to temperature, strain-rate and moisture content. The purpose of performing these experiments was to assist museums in defining safe conditions for modern paintings held in collections. The glass transition temperature of latex paint binders is in close proximity to ambient temperature, resulting in high strain-rate dependence in typical exposure environments. Time dependence of modulus and failure strain is discussed in the context of time-temperature superposition, which was used to extend the experimental time scale. Nonlinear viscoelastic material models are also presented, which incorporate a Prony series with the Ogden or Neo-Hookean hyperelastic function for different TiO2 concentrations.

  18. texreg: Conversion of Statistical Model Output in R to LATEX and HTML Tables

    Directory of Open Access Journals (Sweden)

    Philip Leifeld

    2013-11-01

    Full Text Available A recurrent task in applied statistics is the (mostly manual preparation of model output for inclusion in LATEX, Microsoft Word, or HTML documents usually with more than one model presented in a single table along with several goodness-of-fit statistics. However, statistical models in R have diverse object structures and summary methods, which makes this process cumbersome. This article first develops a set of guidelines for converting statistical model output to LATEX and HTML tables, then assesses to what extent existing packages meet these requirements, and finally presents the texreg package as a solution that meets all of the criteria set out in the beginning. After providing various usage examples, a blueprint for writing custom model extensions is proposed.

  19. Gloves against mineral oils and mechanical hazards: composites of carboxylated acrylonitrile-butadiene rubber latex.

    Science.gov (United States)

    Krzemińska, Sylwia; Rzymski, Władysław M; Malesa, Monika; Borkowska, Urszula; Oleksy, Mariusz

    2016-09-01

    Resistance to permeation of noxious chemical substances should be accompanied by resistance to mechanical factors because the glove material may be torn, cut or punctured in the workplace. This study reports on glove materials, protecting against mineral oils and mechanical hazards, made of carboxylated acrylonitrile-butadiene rubber (XNBR) latex. The obtained materials were characterized by a very high resistance of the produced materials to oil permeation (breakthrough time > 480 min). The mechanical properties, and especially tear resistance, of the studied materials were improved after the addition of modified bentonite (nanofiller) to the XNBR latex mixture. The nanocomposite meets the requirements in terms of parameters characterizing tear, abrasion, cut and puncture resistance. Therefore, the developed material may be used for the production of multifunctional protective gloves.

  20. Gloves against mineral oils and mechanical hazards: composites of carboxylated acrylonitrile–butadiene rubber latex

    Science.gov (United States)

    Krzemińska, Sylwia; Rzymski, Władysław M.; Malesa, Monika; Borkowska, Urszula; Oleksy, Mariusz

    2016-01-01

    Resistance to permeation of noxious chemical substances should be accompanied by resistance to mechanical factors because the glove material may be torn, cut or punctured in the workplace. This study reports on glove materials, protecting against mineral oils and mechanical hazards, made of carboxylated acrylonitrile–butadiene rubber (XNBR) latex. The obtained materials were characterized by a very high resistance of the produced materials to oil permeation (breakthrough time > 480 min). The mechanical properties, and especially tear resistance, of the studied materials were improved after the addition of modified bentonite (nanofiller) to the XNBR latex mixture. The nanocomposite meets the requirements in terms of parameters characterizing tear, abrasion, cut and puncture resistance. Therefore, the developed material may be used for the production of multifunctional protective gloves. PMID:26757889

  1. Radiation induced ionic polymerisation and grafting of vinyl monomers

    International Nuclear Information System (INIS)

    Stannett, V.T.

    1981-01-01

    Some special aspects of the radiation induced ionic polymerisation and grafting of vinyl monomers will be described. In particular the effects of solvents on the cationic polymerisation of the vinyl ethers will be discussed in detail. The unequivocal free ion nature of the polymerisation makes such information of considerable general interest. Estimates of the propagation rate constants with free cation polymerisation in solvents of different dielectric constants and solvation powers will be presented. Finally, some observations on the radiation induced graft polymerisation of ethyl vinyl ether to poly(vinyl chloride) and to polypropylene will be presented. (author)

  2. Structural Transitions of Solvent-Free Oligomer-Grafted Nanoparticles

    KAUST Repository

    Chremos, Alexandros

    2011-09-01

    Novel structural transitions of solvent-free oligomer-grafted nanoparticles are investigated by using molecular dynamics simulations of a coarse-grained bead-spring model. Variations in core size and grafting density lead to self-assembly of the nanoparticles into a variety of distinct structures. At the boundaries between different structures, the nanoparticle systems undergo thermoreversible transitions. This structural behavior, which has not been previously reported, deviates significantly from that of simple liquids. The reversible nature of these transitions in solvent-free conditions offers new ways to control self-assembly of nanoparticles at experimentally accessible conditions. © 2011 American Physical Society.

  3. Grafting, pruning, and the antipodal map on measured laminations

    OpenAIRE

    Dumas, David

    2006-01-01

    Grafting a measured lamination on a hyperbolic surface defines a self-map of Teichmuller space, which is a homeomorphism by a result of Scannell and Wolf. In this paper we study the large-scale behavior of pruning, which is the inverse of grafting. Specifically, for each conformal structure $X \\in \\T(S)$, pruning $X$ gives a map $\\ML(S) \\to \\T(S)$. We show that this map extends to the Thurston compactification of $\\T(S)$, and that its boundary values are the natural antipodal involution relat...

  4. Numerical Simulation and Experimental Validation of the Inflation Test of Latex Balloons

    Directory of Open Access Journals (Sweden)

    Claudio Bustos

    Full Text Available Abstract Experiments and modeling aimed at assessing the mechanical response of latex balloons in the inflation test are presented. To this end, the hyperelastic Yeoh material model is firstly characterized via tensile test and, then, used to numerically simulate via finite elements the stress-strain evolution during the inflation test. The numerical pressure-displacement curves are validated with those obtained experimentally. Moreover, this analysis is extended to a biomedical problem of an eyeball under glaucoma conditions.

  5. Numerical Simulation and Experimental Validation of the Inflation Test of Latex Balloons

    OpenAIRE

    Bustos, Claudio; Herrera, Claudio García; Celentano, Diego; Chen, Daming; Cruchaga, Marcela

    2016-01-01

    Abstract Experiments and modeling aimed at assessing the mechanical response of latex balloons in the inflation test are presented. To this end, the hyperelastic Yeoh material model is firstly characterized via tensile test and, then, used to numerically simulate via finite elements the stress-strain evolution during the inflation test. The numerical pressure-displacement curves are validated with those obtained experimentally. Moreover, this analysis is extended to a biomedical problem of an...

  6. Comparison of the effect of using latex and nitrile gloves hand dexterity among Iranian population

    Directory of Open Access Journals (Sweden)

    T. Allahyari

    2014-02-01

    .Conclusion: Considering that there was no significant difference in the score of both fine finger and gross hand dexterity while using nitrile gloves as compared to the control condition (without gloves, means that use of nitrile gloves has no adverse effect on hand dexterity therefore, using nitrile gloves is recommended as a alternative for the latex gloves, considering the additional advantage of no allergic reaction in this gloves.

  7. Effect of parity on fetal and maternal microchimerism: interaction of grafts within a host?

    Science.gov (United States)

    Guthrie, Katherine A.; Aydelotte, Tessa M.; Waldorf, Kristina M. Adams; Nelson, J. Lee

    2010-01-01

    Small amounts of genetically foreign cells (microchimerism, Mc) traffic between a mother and fetus during pregnancy. Commonly, these grafts durably persist. For women, multiple naturally acquired Mc grafts can accrue, as they harbor Mc from their own mothers (maternal Mc, MMc) and subsequently acquire fetal Mc (FMc) through pregnancy. The nature of interactions between these naturally acquired grafts may inform, and be informed by, observations in transplantation, including the effect of noninherited maternal HLA antigens (NIMA) and double-unit cord blood transplantation (CBT). We asked whether FMc and MMc are impacted by the addition of new grafts as evaluated by increasing parity. Mc was identified by quantitative PCR for a nonshared polymorphism unique to the Mc source. Despite increasing sources of Mc, FMc did not increase with increasing parity. MMc concentration was significantly lower with increasing parity. The odds ratio for detection of MMc for 2 or more births compared with 1 birth was .11 (95% CI 0.03-0.42, P = .001). These observations suggest that interactions occur among naturally acquired grafts and are of interest in light of recent observations of graft-graft interaction resulting in predominance of 1 unit in double-unit CBT and the correlation of MMc with the NIMA effect. PMID:20628146

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

    Directory of Open Access Journals (Sweden)

    Jung-Hwan Lee

    2014-01-01

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

  9. Sequence and expression analyses of ethylene response factors highly expressed in latex cells from Hevea brasiliensis.

    Directory of Open Access Journals (Sweden)

    Piyanuch Piyatrakul

    Full Text Available The AP2/ERF superfamily encodes transcription factors that play a key role in plant development and responses to abiotic and biotic stress. In Hevea brasiliensis, ERF genes have been identified by RNA sequencing. This study set out to validate the number of HbERF genes, and identify ERF genes involved in the regulation of latex cell metabolism. A comprehensive Hevea transcriptome was improved using additional RNA reads from reproductive tissues. Newly assembled contigs were annotated in the Gene Ontology database and were assigned to 3 main categories. The AP2/ERF superfamily is the third most represented compared with other transcription factor families. A comparison with genomic scaffolds led to an estimation of 114 AP2/ERF genes and 1 soloist in Hevea brasiliensis. Based on a phylogenetic analysis, functions were predicted for 26 HbERF genes. A relative transcript abundance analysis was performed by real-time RT-PCR in various tissues. Transcripts of ERFs from group I and VIII were very abundant in all tissues while those of group VII were highly accumulated in latex cells. Seven of the thirty-five ERF expression marker genes were highly expressed in latex. Subcellular localization and transactivation analyses suggested that HbERF-VII candidate genes encoded functional transcription factors.

  10. Latex-mediated synthesis of ZnS nanoparticles: green synthesis approach

    Energy Technology Data Exchange (ETDEWEB)

    Hudlikar, Manish; Joglekar, Shreeram [University of Pune, Division of Biochemistry, Department of Chemistry (India); Dhaygude, Mayur [National Chemical Laboratory, Polymer Science and Engineering Division (India); Kodam, Kisan, E-mail: kodam@chem.unipune.ac.in [University of Pune, Division of Biochemistry, Department of Chemistry (India)

    2012-05-15

    A low-cost, green synthesis of ZnS nanoparticles is reported using 0.3 % latex solution prepared from Jatropha curcas L. ZnS nanoparticles were characterized by X-ray diffraction, selected area electron diffraction, transmission electron microscopy, energy dispersive analysis of X-rays, UV-vis optical absorption and photoluminescence techniques. Fourier Transform Infrared Spectroscopy was performed to find the role of cyclic peptides namely curcacycline A (an octapeptide), curcacycline B (a nonapeptide) and curcain (an enzyme) as a possible reducing and stabilizing agents present in the latex of J. curcas L. The average size of ZnS nanoparticles was found to be 10 nm. Latex of J. curcas L. itself acts as a source of sulphide (S{sup -2}) ions that are donated to Zn ions under present experimental conditions. Source of sulphide (S{sup -2}) ions is still unclear, but we speculate that cysteine or thiol residues present in enzyme curcain may be donating these sulphide (S{sup -2}) ions.

  11. Latex-mediated synthesis of ZnS nanoparticles: green synthesis approach

    Science.gov (United States)

    Hudlikar, Manish; Joglekar, Shreeram; Dhaygude, Mayur; Kodam, Kisan

    2012-05-01

    A low-cost, green synthesis of ZnS nanoparticles is reported using 0.3 % latex solution prepared from Jatropha curcas L. ZnS nanoparticles were characterized by X-ray diffraction, selected area electron diffraction, transmission electron microscopy, energy dispersive analysis of X-rays, UV-vis optical absorption and photoluminescence techniques. Fourier Transform Infrared Spectroscopy was performed to find the role of cyclic peptides namely curcacycline A (an octapeptide), curcacycline B (a nonapeptide) and curcain (an enzyme) as a possible reducing and stabilizing agents present in the latex of J. curcas L. The average size of ZnS nanoparticles was found to be 10 nm. Latex of J. curcas L. itself acts as a source of sulphide (S-2) ions that are donated to Zn ions under present experimental conditions. Source of sulphide (S-2) ions is still unclear, but we speculate that cysteine or thiol residues present in enzyme curcain may be donating these sulphide (S-2) ions.

  12. Latex-mediated synthesis of ZnS nanoparticles: green synthesis approach

    International Nuclear Information System (INIS)

    Hudlikar, Manish; Joglekar, Shreeram; Dhaygude, Mayur; Kodam, Kisan

    2012-01-01

    A low-cost, green synthesis of ZnS nanoparticles is reported using 0.3 % latex solution prepared from Jatropha curcas L. ZnS nanoparticles were characterized by X-ray diffraction, selected area electron diffraction, transmission electron microscopy, energy dispersive analysis of X-rays, UV–vis optical absorption and photoluminescence techniques. Fourier Transform Infrared Spectroscopy was performed to find the role of cyclic peptides namely curcacycline A (an octapeptide), curcacycline B (a nonapeptide) and curcain (an enzyme) as a possible reducing and stabilizing agents present in the latex of J. curcas L. The average size of ZnS nanoparticles was found to be 10 nm. Latex of J. curcas L. itself acts as a source of sulphide (S −2 ) ions that are donated to Zn ions under present experimental conditions. Source of sulphide (S −2 ) ions is still unclear, but we speculate that cysteine or thiol residues present in enzyme curcain may be donating these sulphide (S −2 ) ions.

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

    Science.gov (United States)

    Määttänen, Anni; Ihalainen, Petri; Törngren, Björn; Rosqvist, Emil; Pesonen, Markus; Peltonen, Jouko

    2016-02-01

    Different length scale alterations in topography, surface texture, and symmetry are known to evoke diverse cell behavior, including adhesion, orientation, motility, cytoskeletal condensation, and modulation of intracellular signaling pathways. In this work, self-supported latex films with well-defined isotropic/anisotropic surface features and hierarchical morphologies were fabricated by a peel-off process from different template surfaces. In addition, the latex films were used as substrates for evaporated ultrathin gold films with nominal thicknesses of 10 and 20 nm. Optical properties and topography of the samples were characterized using UV-vis spectroscopy and Atomic Force Microscopy (AFM) measurements, respectively. The latex films showed high-level transmittance of visible light, enabling the fabrication of semi-transparent gold electrodes. Electrochemical impedance spectroscopy (EIS) measurements were carried out for a number of days to investigate the long-term stability of the electrodes. The effect of 1-octadecanethiol (ODT) and HS(CH2)11OH (MuOH) thiolation and protein (human serum albumin, HSA) adsorption on the impedance and capacitance was studied. In addition, cyclic voltammetry (CV) measurements were carried out to determine active medicinal components, i.e., caffeic acid with interesting biological activities and poorly water-soluble anti-inflammatory drug, piroxicam. The results show that the fabrication procedure presented in this study enables the formation of platforms with hierarchical morphologies for multimodal (optical and electrical) real-time monitoring of length-scale-dependent biomaterial-surface interactions.

  14. Evaluation of force degradation characteristics of orthodontic latex elastics in vitro and in vivo.

    Science.gov (United States)

    Wang, Tong; Zhou, Gang; Tan, Xianfeng; Dong, Yaojun

    2007-07-01

    To evaluate the characteristics of force degradation of latex elastics in clinical applications and in vitro studies. Samples of 3/16-inch latex elastics were investigated, and 12 students between the ages of 12 and 15 years were selected for the intermaxillary and intramaxillary tractions. The elastics in the control groups were set in artificial saliva and dry room conditions and were stretched 20 mm. The repeated-measure two-way analysis of variance and nonlinear regression analysis were used to identify statistical significance. Overall, there were statistically significant differences between the different methods and observation intervals. At 24- and 48-hour time intervals, the force decreased during in vivo testing and in artificial saliva (P .05). In intermaxillary traction the percentage of initial force remaining after 48 hours was 61%. In intramaxillary traction and in artificial saliva the percentage of initial force remaining was 71%, and in room conditions 86% of initial force remained. Force degradation of latex elastics was different according to their environmental conditions. There was significantly more force degradation in intermaxillary traction than in intramaxillary traction. The dry room condition caused the least force loss. There were some differences among groups in the different times to start wearing elastics in intermaxillary traction but no significant differences in intramaxillary traction.

  15. Clonal stability of latex yield in eleven clones of Hevea brasiliensis Muell. Arg.

    Directory of Open Access Journals (Sweden)

    K.O. Omokhafe

    2003-01-01

    Full Text Available Eleven Hevea brasiliensis clones were evaluated for clonal stability of latex yield. A randomized complete block design was used with four replicates, two locations, seven years and three periods per year. Stability analysis was based on clone x year and clone x year x location interactions. Five stability parameters viz environmental variance, shukla's stability variance, regression of clonal latex yield on environmental index, variance due to regression and variance due to deviation from regression were applied. There was significant clone x environment effect at the two levels of interaction. Among the eleven clones, C 162 was outstanding for clonal stability and it can serve as donor parent for stability alleles. Three clones (C 76, C 150 and C 154 were also stable. The four stable clones (C 76, C 150, C 154 and C 162 are suitable for broad-spectrum recommendation for latex yield. Five clones (C 83, C 143, C 163, C 202 and RRIM 600 will require environment-specific recommendation because of their unstable phenotype. The stability feature of two clones (C 145 and C 159 was not clear and this will be investigated in subsequent studies.

  16. Antimalarial Activity of the Chemical Constituents of the Leaf Latex of Aloe pulcherrima Gilbert and Sebsebe.

    Science.gov (United States)

    Teka, Tekleab; Bisrat, Daniel; Yeshak, Mariamawit Yonathan; Asres, Kaleab

    2016-10-28

    Malaria is one of the three major global public health threats due to a wide spread resistance of the parasites to the standard antimalarial drugs. Considering this growing problem, the ethnomedicinal approach in the search for new antimalarial drugs from plant sources has proven to be more effective and inexpensive. The leaves of Aloe pulcherrima Gilbert and Sebsebe, an endemic Ethiopian plant, are locally used for the treatment of malaria and other infectious diseases. Application of the leaf latex of A. pulcherrima on preparative silica gel TLC led to the isolation of two C -glycosylated anthrones, identified as nataloin ( 1 ) and 7-hydroxyaloin ( 2 ) by spectroscopic techniques (UV, IR, ¹H- and 13 C-NMR, HR-ESIMS). Both the latex and isolated compounds displayed antimalarial activity in a dose-independent manner using a four-day suppressive test, with the highest percent suppression of 56.2% achieved at 200 mg/kg/day for 2 . The results indicate that both the leaf latex of A. pulcherrima and its two major constituents are endowed with antiplasmodial activities, which support the traditional use of the leaves of the plant for the treatment of malaria.

  17. SYSTEMES DE RECOLTE DU LATEX ADAPTES A LA SAIGNEE ...

    African Journals Online (AJOL)

    AISA

    des arbres. Il s'agira de définir l'influence de ..... CIRAD-Cultures pérennes, éd.,. Montpellier, France .... Indian. Journal of Natural Rubber Research,. 15(1) : 66 - 71. Obouayeba S. 2005.Contribution à la ... Academy Hevea Malaysia, Malaysian.

  18. A Review on Grafting of Biofibers for Biocomposites

    Directory of Open Access Journals (Sweden)

    Liqing Wei

    2016-04-01

    Full Text Available A recent increase in the use of biofibers as low-cost and renewable reinforcement for the polymer biocomposites has been seen globally. Biofibers are classified into: lignocellulosic fibers (i.e., cellulose, wood and natural fibers, nanocellulose (i.e., cellulose nanocrystals and cellulose nanofibrils, and bacterial cellulose, while polymer matrix materials can be petroleum based or bio-based. Green biocomposites can be produced using both biobased fibers and polymers. Incompatibility between the hydrophilic biofibers and hydrophobic polymer matrix can cause performance failure of resulting biocomposites. Diverse efforts have focused on the modification of biofibers in order to improve the performances of biocomposites. “Grafting” copolymerization strategy can render the advantages of biofiber and impart polymer properties onto it and the performance of biocomposites can be tuned through changing grafting parameters. This review presents a short overview of various “grafting” methods which can be directly or potentially employed to enhance the interaction between biofibers and a polymer matrix for biocomposites. Major grafting techniques, including ring opening polymerization, grafting via coupling agent and free radical induced grafting, have been discussed. Improved properties such as mechanical, thermal, and water resistance have provided grafted biocomposites with new opportunities for applications in specific industries.

  19. Evolution of skin grafting for treatment of burns: Reverdin pinch grafting to Tanner mesh grafting and beyond.

    Science.gov (United States)

    Singh, Mansher; Nuutila, Kristo; Collins, K C; Huang, Anne

    2017-09-01

    Skin grafting is the current standard care in the treatment of full thickness burns. It was first described around 1500 BC but the vast majority of advancements have been achieved over the past 200 years. An extensive literature review was conducted on Pubmed, Medline and Google Scholar researching the evolution of skin grafting techniques. The authors concentrated on the major landmarks of skin grafting and also provide an overview of ongoing research efforts in this field. The major innovations of skin grafting include Reverdin pinch grafting, Ollier grafting, Thiersch grafting, Wolfe grafting, Padgett dermatome and modifications, Meek-wall microdermatome and Tanner mesh grafting. A brief description of the usage, advantages and limitations of each technique is included in the manuscript. Skin grafting technique have evolved significantly over past 200 years from Reverdin pinch grafting to modern day meshed skin grafts using powered dermatome. Increasing the expansion ratio and improving the cosmetic and functional outcome are the main focus of ongoing skin grafting research and emerging techniques (such as Integra ® , Recell ® , Xpansion ® ) are showing promise. Copyright © 2017 Elsevier Ltd and ISBI. All rights reserved.

  20. Prevalence and clinical impact of sensitization to latex and fruits in dentistry students at the University of Antioquia, and its relationship with allergy to fruits

    Directory of Open Access Journals (Sweden)

    Echenique Manrique, Alejandro

    2015-04-01

    Full Text Available Objective: To determine the prevalence and clinical impact of sensitization to latex and to five tropical fruits (banana, avocado, kiwi, pineapple and passion fruit in dentistry students. Methods: Analytical cross-sectional study of 128 dentistry students at University of Antioquia in Medellín, Colombia. Information was collected by means of a questionnaire and skin prick tests with latex and fruits were done. Results: All students reported having had contact with latex. Nine of them informed at least one episode of adverse reaction to contact with latex without proof of sensitization to it. Five reported at least one reaction with one of the fruits, but skin prick tests were negative. Four of the 14 students who reported gastrointestinal symptoms were sensitized to latex or to one of the tested fruits. Overall, latex sensitization rate was 3.1%. Conclusion: This percentage of sensitization to latex is lower than that in other studies; this may be due to the expression of immune mechanisms other than IgE mediation. We failed to demonstrate a higher sensitization rate to latex as students advanced in their career. The association between gastrointestinal symptoms and sensitization to both fruit and latex is to be emphasized.