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Sample records for contact materials enzymes

  1. Contact materials for nanoelectronics

    KAUST Repository

    Alshareef, Husam N.; Quevedo-Ló pez, Manuel Angel Quevedo; Majhi, Prashant

    2011-01-01

    In this article, we review current research activities in contact material development for electronic and nanoelectronic devices. A fundamental issue in contact materials research is to understand and control interfacial reactions and phenomena

  2. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2013. Scientific Opinion on Flavouring Group Evaluation 21, Revision 4 (FGE.21Rev4)

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Binderup, Mona-Lise; Frandsen, Henrik Lauritz

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 59 flavouring substances in the Flavouring Group Evaluation 21, Revision 4, using the Procedure in Commission Regulation (EC) No 1565/2000. This revision...... of these flavouring substances, the specifications for the materials of commerce have also been considered. Adequate specifications including complete purity criteria and identity for the materials of commerce have been provided for all 41 candidate substances...

  3. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 309 (FGE.309): Sodium Diacetate

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate sodium diacetate [FL-no: 16.073] in the Flavouring Group Evaluation 309, using the Procedure in Commission Regulation (EC) No 1565/2000. However, although...

  4. Contact materials for nanoelectronics

    KAUST Repository

    Alshareef, Husam N.

    2011-02-01

    In this article, we review current research activities in contact material development for electronic and nanoelectronic devices. A fundamental issue in contact materials research is to understand and control interfacial reactions and phenomena that modify the expected device performance. These reactions have become more challenging and more difficult to control as new materials have been introduced and as device sizes have entered the deep nanoscale. To provide an overview of this field of inquiry, this issue of MRS Bulletin includes articles on gate and contact materials for Si-based devices, junction contact materials for Si-based devices, and contact materials for alternate channel substrates (Ge and III-V), nanodevices. © 2011 Materials Research Society.

  5. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2013. Scientific Opinion on Flavouring Group Evaluation 76, Revision 1 (FGE.76Rev1)

    OpenAIRE

    Beltoft, Vibe Meister; Binderup, Mona-Lise; Frandsen, Henrik Lauritz; Lund, Pia; Nørby, Karin Kristiane

    2013-01-01

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to consider evaluations of flavouring substances assessed since 2000 by the Joint FAO/WHO Expert Committee on Food Additives (JECFA), and to decide whether further evaluation is necessary, as laid down in Commission Regulation (EC) No 1565/2000. The present opinion concerns a group of 26 sulphur-containing heterocyclic compounds evaluated by the JECFA at the 59th m...

  6. EFSA EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 304 (FGE.304): Five carboxamides from chemical group 30

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate five flavouring substances in the Flavouring Group Evaluation 304, using the Procedure in Commission Regulation (EC) No 1565/2000. None of the substances...... data are required. Besides the safety assessment of these flavouring substances, the specifications for the materials of commerce have also been considered. Specifications including complete purity criteria and identity for the materials of commerce have been provided for all five candidate substances....

  7. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF) ; Scientific Opinion on Flavouring Group Evaluation 305 (FGE.305): L - Methionylglycine of chemical group 34

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Binderup, Mona-Lise; Frandsen, Henrik Lauritz

    use in foods that are not heated or intended to be heated. Besides the safety assessment of the flavouring substance, the specifications for the material of commerce have also been considered. Adequate specifications including complete purity criteria and identity for the material of commerce have......The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate one flavouring substance, the dipeptide L-methionylglycine [FL-no: 17.037], in the Flavouring Group Evaluation 305, using the Procedure in Commission...... been provided for the candidate substance. © European Food Safety Authority, 2013...

  8. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2013. Scientific Opinion on Flavouring Group Evaluation 24, Revision 2 (FGE.24Rev2)

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Binderup, Mona-Lise; Frandsen, Henrik Lauritz

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 24 flavouring substances in the Flavouring Group Evaluation 24, Revision 2, using the Procedure in Commission Regulation (EC) No 1565/2000. This revision...... the safety assessment of these flavouring substances, the specifications for the materials of commerce have also been considered. Adequate specifications including complete purity criteria and identity for the materials of commerce have been provided for all 24 candidate substances....

  9. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2013. Scientific Opinion on Flavouring Group Evaluation 21, Revision 4 (FGE.21Rev4)

    OpenAIRE

    Beltoft, Vibe Meister; Binderup, Mona-Lise; Frandsen, Henrik Lauritz; Lund, Pia; Nørby, Karin Kristiane

    2013-01-01

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 59 flavouring substances in the Flavouring Group Evaluation 21, Revision 4, using the Procedure in Commission Regulation (EC) No 1565/2000. This revision is made due to the inclusion of the assessment of new toxicity data on one supporting substance 5,6-dihydro-2,4,6-tris(2-methylpropyl)-4H-1,3,5-dithiazine [FL-no: 15.113], which is considered to be str...

  10. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 303 (FGE.303): Spilanthol from chemical group 30

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Scientific Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (the Panel) was asked to provide scientific advice to the Commission on the implications for human health of chemically defined flavouring substances used in or on foodstuffs in the Member States. In particular...... of the flavouring substances in Europe. However, when the Panel examined the information provided by the European Flavouring Industry on the use levels in various foods, it appeared obvious that the MSDI approach in a number of cases would grossly underestimate the intake by regular consumers of products flavoured...... whether the conclusion for the candidate substance can be applied to the material of commerce, it is necessary to consider the available specifications. Adequate specifications including complete purity criteria and identity for the material of commerce have been provided for the flavouring substance...

  11. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2013. Scientific Opinion on Flavouring Group Evaluation 93, Revision 1 (FGE.93Rev1)

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Binderup, Mona-Lise; Frandsen, Henrik Lauritz

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to consider evaluations of flavouring substances assessed since 2000 by the Joint FAO/WHO Expert Committee on Food Additives (the JECFA), and to decide whether further...... through a stepwise approach that integrates information on structure-activity relationships, intake from current uses, toxicological threshold of concern, and available data on metabolism and toxicity. The two substances 5-ethyl-4-methyl-2-(2-methylpropyl)-thiazoline [FL-no: 15.130] and 5-ethyl-4-methyl-2...... and agrees with the JECFA conclusion, “No safety concern at estimated levels of intake as flavouring substances” based on the MSDI approach. Besides the safety assessment of these flavouring substances, the specifications for the materials of commerce have also been considered and for all five substances...

  12. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2013. Scientific Opinion on Flavouring Group Evaluation 76, Revision 1 (FGE.76Rev1)

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Binderup, Mona-Lise; Frandsen, Henrik Lauritz

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to consider evaluations of flavouring substances assessed since 2000 by the Joint FAO/WHO Expert Committee on Food Additives (JECFA), and to decide whether further...... by Industry for use as a flavouring substance in Europe and will therefore not be considered any further. The substances were evaluated through a stepwise approach that integrates information on structure-activity relationships, intake from current uses, toxicological threshold of concern, and available data...... as flavouring substances, as these substances could not be evaluated because of concern with respect to genotoxicity. Besides the safety assessment of these flavouring substances, the specifications for the materials of commerce have also been considered and for all 26 substances, the information is adequate....

  13. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 310 (FGE.310): Rebaudioside A from chemical group 30

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate rebaudioside A [FL-no: 16.113], a steviol glycoside. The substance was not considered to have genotoxic potential. Since a comprehensive and adequate...... toxicological database, including human studies, is available for steviol glycosides, the Panel based its evaluation of rebaudioside A on a comparison of the ADI of 4 mg/kg bw, expressed as steviol, established by EFSA, with the estimated dietary exposure figures based on the MSDI and mTAMDI approaches....... The Panel concluded that rebaudioside A [FL-no: 16.113] would not give rise to safety concerns at the estimated level of intake arising from its use as flavouring substance....

  14. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2014. Scientific Opinion on Flavouring Group Evaluation 304, Revision 1 (FGE.304Rev1): Four carboxamides from Chemical Groups 30

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Binderup, Mona-Lise; Frandsen, Henrik Lauritz

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate four flavouring substances in the Flavouring Group Evaluation 304, Revision 1 (FGE.304Rev1) using the Procedure in Commission Regulation (EC) No 1565...... criteria and identity for the materials of commerce have been provided for all four candidate substances....

  15. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2014. Scientific Opinion on Flavouring Group Evaluation 11, Revision 3 (FGE.11Rev3): Aliphatic dialcohols, diketones, and hydroxyketones from chemical groups 8 and 10

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Frandsen, Henrik Lauritz; Nørby, Karin Kristiane

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 11 flavouring substances in the Flavouring Group Evaluation 11, Revision 3, using the Procedure in Commission Regulation (EC) No 1565/2000. The substances......, the specifications for the materials of commerce have also been considered. Specifications including complete purity criteria and identity for the materials of commerce have been provided for all candidate substances....

  16. EFSA Panel on Food Contact Material, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 47, Revision 1: Bi- and tricyclic secondary, ketones and related esters from chemical groups 7 and 8

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate six flavouring substances in the Flavouring Group Evaluation 47, including an additional two substances in this Revision 1, using the Procedure in Commission...... of these flavouring substances, the specifications for the materials of commerce have also been considered. Adequate specifications including complete purity criteria and identity fo the materials of commerce have been provided for all six candidate substances....

  17. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2014. Scientific Opinion on Flavouring Group Evaluation 215 (FGE.215): Seven α,β-Unsaturated Cinnamyl Ketones from subgroup 3.2 of FGE.19

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Binderup, Mona-Lise; Lund, Pia

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate the genotoxic potential of flavouring substances from subgroup 3.2 of FGE.19 in the Flavouring Group Evaluation 215 (FGE.215). The Flavour Industry has...

  18. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 96 (FGE.96): Consideration of 88 flavouring substances considered by EFSA for which EU production volumes / anticipated production volumes have been submitted

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to consider evaluations of flavouring substances assessed since 2000 by the Joint FAO/WHO Expert Committee on Food Additives (the JECFA), and to decide whether further...

  19. EFSA CEF Panel (EFSA Panel on Fo od Contact Materials, Enzymes, Flavourings and Proce ssing Aids), 2015. Scientific Opinion on Flavouring Group Evalua tion 35, Revision 1 (FGE.35Rev1)

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Nørby, Karin Kristiane

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate three flavouring substances in the Flavouring Group Evaluation 35, Revision 1, using the Procedure in Commission Regulation (EC) No 1565/2000. The present ...

  20. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2015. Scientific Opinion on Flavouring Group Evaluation 21, Revision 5 (FGE.21Rev5): Thiazoles, thiophenes, thiazoline and thienyl derivatives from chemical groups 29 and 30

    DEFF Research Database (Denmark)

    Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 41 flavouring substances in Flavouring Group Evaluation 21, Revision 5, using the Procedure in Commission Regulation (EC) No 1565/2000. This revision...... have also been considered. Adequate specifications, including complete purity criteria and identity for the materials of commerce, have been provided for all 41 candidate substances....

  1. Nordic project food contact materials

    DEFF Research Database (Denmark)

    Li, Ågot; Tesdal Håland, Julie; Petersen, Jens Højslev

    Denmark, Finland, Faroe Islands, Iceland, Norway and Sweden have in 2013––2015 conducted a Nordic project on food contact materials. Food contact materials are used in all stages of food production and can be a general source of contamination. The food safety authorities in most of the Nordic...... countries have had a limited focus on the FCM area with the exception of Denmark and Finland. The aim of the project was therefore to control establishments producing, importing or using plastic food contact materials as well as to increase the knowledge of the inspectors performing these controls....... The focus of the inspections was to control the declaration of compliance (DoC) for plastic food contact materials. The requirement for a Doc is mandatory in order to ensure that the FCM complies with the legislation. In addition some products were analyzed for phthalates....

  2. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2015. Scientific Opinion on Flavouring Group Evaluation 303, Revision 1 (FGE.303Rev1): Spilanthol from chemical group 30

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Nørby, Karin Kristiane

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate the flavouring substance spilanthol [FL-no: 16.121] in Flavouring Group Evaluation 303, Revision 1, using the Procedure according to Commission Regulation...... (MSDI) approach. Besides the safety assessment of the flavouring substance, the specifications for the material of commerce have also been considered. Adequate specifications including complete purity criteria and identity for the material of commerce have been provided for the candidate substance....

  3. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2015. Scientific Opinion on Flavouring Group Evaluation 25, Revision 3 (FGE.25Rev3): Aliphatic hydrocarbons from chemical group 31

    DEFF Research Database (Denmark)

    Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 14 flavouring substances in the Flavouring Group Evaluation 25, Revision 3, using the Procedure in Commission Regulation (EC) No 1565/2000. None...... on the basis of the MSDI approach. Besides the safety assessment of these flavouring substances, the specifications for the materials of commerce have also been considered. Adequate specifications including complete purity and identity criteria for the materials of commerce have been provided for all 14...

  4. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids ), 2014. Scientific Opinion on Flavouring Group Evaluation 200 (FGE.200): 74 α , β -unsaturated aldehydes and precursors from subgroup 1.1.1 of FGE.19

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Binderup, Mona-Lise; Frandsen, Henrik Lauritz

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate the genotoxic potential of 74 flavouring substances from subgroup 1.1.1 of FGE.19 in the Flavouring Group Evaluation 200 (FGE.200). The Flavour Industry has...... provided additional genotoxicity studies for one representative substance in FGE.200, namely hex-2(trans)-enal [FL-no 05.073], and for other two substances in the same subgroup, namely 2-dodecenal [05.037] and 2-nonenal [05.171]. The Panel has evaluated these data and concluded that the concern still...

  5. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 12, Revision 2 (FGE.12Rev2): Primary saturated or unsaturated alicyclic alcohol, aldehyde, acid, and esters from chemical group 7

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The European Food Safety Authority (EFSA) asked the Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (the Panel) to provide scientific advice to the Commission on the implications for human health of chemically defined flavouring substances used in or on foodstuffs....... However, this does not preclude evaluation of the flavouring substances in the present group using the Procedure (SCF, 1999a). It is considered that on the basis of the default MSDI approach these nine flavouring substances would not give rise to safety concerns at the estimated levels of intake arising...

  6. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 10, Revision 2 (FGE.10Rev2): Aliphatic primary and secondary saturated and unsaturated alcohols, aldehydes, acetals, carboxylic acids and esters containing

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 61 flavouring substances in the Flavouring Group Evaluation 10, Revision 2, using the Procedure in Commission Regulation (EC) No 1565/2000. None of the sub......The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 61 flavouring substances in the Flavouring Group Evaluation 10, Revision 2, using the Procedure in Commission Regulation (EC) No 1565/2000. None...... of the substances were considered to have genotoxic potential. The substances were evaluated through a stepwise approach (the Procedure) that integrates information on structure-activity relationships, intake from current uses, toxicological threshold of concern, and available data on metabolism and toxicity....... The Panel concluded that the 61 substances do not give rise to safety concerns at their levels of dietary intake, estimated on the basis of the MSDI approach. Besides the safety assessment of these flavouring substances, the specifications for the materials of commerce have also been considered. For four...

  7. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 25, Revision 2 (FGE.25Rev2): Aliphatic and aromatic hydrocarbons from chemical group 31

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 37 flavouring substances in the Flavouring Group Evaluation 25, Revision 2, using the Procedure in Commission Regulation (EC) No 1565/2000. None of the sub......The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 37 flavouring substances in the Flavouring Group Evaluation 25, Revision 2, using the Procedure in Commission Regulation (EC) No 1565/2000. None...... of the substances were considered to have genotoxic potential. The substances were evaluated through a stepwise approach (the Procedure) that integrates information on structure-activity relationships, intake from current uses, toxicological threshold of concern, and available data on metabolism and toxicity...... assessment of these flavouring substances, the specifications for the materials of commerce have also been considered. For five substances, the composition of the stereoisomeric mixture has to be specified further....

  8. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 21, Revision 3 (FGE.21Rev3): Thiazoles, thiophenes, thiazoline and thienyl derivatives from chemical groups 29 and 30

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 59 flavouring substances in the Flavouring Group Evaluation 21, including an additional three substances in this Revision 3, using the Procedure in Commiss......The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 59 flavouring substances in the Flavouring Group Evaluation 21, including an additional three substances in this Revision 3, using the Procedure.......086, 15.090, 15.099, 15.114, 15.119 and 15.133] were considered to have genotoxic potential. The remaining 52 substances were evaluated through a stepwise approach (the Procedure) that integrates information on structure-activity relationships, intake from current uses, toxicological threshold of concern.......092, 15.093, 15.094, 15.096, 15.097, 15.106, 15.107, 15.129 and 15.135] evaluated through the Procedure, no appropriate NOAEL was available and additional data are required. Besides the safety assessment of these flavouring substances, the specifications for the materials of commerce have also been...

  9. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 300 (FGE.300): One cyclo-aliphatic amide from chemical group 33

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate a flavouring substance in the Flavouring Group Evaluation 300 using the Procedure in Commission Regulation (EC) No 1565/2000. The substance was not conside......The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate a flavouring substance in the Flavouring Group Evaluation 300 using the Procedure in Commission Regulation (EC) No 1565/2000. The substance...... was not considered to have genotoxic potential. The substance was evaluated through a stepwise approach (the Procedure) that integrates information on structure-activity relationships, intake from current uses, toxicological threshold of concern, and available data on metabolism and toxicity. The Panel concluded...... that for the substance [FL-no: 16.115] evaluated through the Procedure, no appropriate NOAEL was available and additional data are required. Besides the safety assessment of this flavouring substance, the specifications for the materials of commerce have also been considered. The composition of the stereoisomeric...

  10. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2014. Scientific Opinion on Flavouring Group Evaluation 300, Revision 1 (FGE.300Rev1): One cyclo-aliphatic amide from chemical group 33

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Frandsen, Henrik Lauritz; Nørby, Karin Kristiane

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate a flavouring substance,cyclopropanecarboxylic acid (2-isopropyl-5-methyl-cyclohexyl)-amide [FL-no: 16.115] in the Flavouring Group Evaluation 300, Revision 1....... The substance was not considered to have genotoxic potential. The substance was evaluated through a stepwise approach (the Procedure) that integrates information on structure-activity relationships, intake from current uses, toxicological threshold of concern, and available data on metabolism and toxicity....... The Panel concluded that the substance [FL-no: 16.115] does not give rise to safety concern at its levels of dietary intake estimated on the basis of the Maximised Survey-derived Daily Intake MSDI approach. Besides the safety assessment of this flavouring substance, the specifications for the material...

  11. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 17, Revision 3 (FGE.17Rev3): Pyrazine derivatives from chemical group 24

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 28 flavouring substances in the Flavouring Group Evaluation 17, including seven additional substances considered in this Revision 3, using the Procedure......-activity relationships, intake from current uses, toxicological threshold of concern, and available data on metabolism and toxicity. The Panel concluded that 24 substances [FL-no: 14.057, 14.081, 14.083, 14.084, 14.086, 14.087, 14.091, 14.097, 14.099, 14.101, 14.102, 14.108, 14.109, 14.111, 14.112, 14.113, 14.122, 14...... substances, the specifications for the materials of commerce have also been considered and for one substance [FL-no: 14.102], the composition of mixture has not been specified sufficiently....

  12. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 22, Revision 1 (FGE.22Rev1): Ring substituted phenolic substances from chemical groups 21 and 25

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 28 flavouring substances in the Flavouring Group Evaluation 22, Revision 1, using the Procedure in Commission Regulation (EC) No 1565/2000. The substance 3...... through a stepwise approach (the Procedure) that integrates information on structure-activity relationships, intake from current uses, toxicological threshold of concern, and available data on metabolism and toxicity. The Panel concluded that these 27 candidate substances do not give rise to safety...... concerns at their levels of dietary intake, estimated on the basis of the MSDI approach. Adequate specifications for the materials of commerce are available for all 27 flavouring substances evaluated through the Procedure....

  13. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 17, Revision 2 (FEG.17Rev2): Pyrazine derivatives from chemical group 24

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 21 flavouring substances in the Flavouring Group Evaluation 17, Revision 2, using the Procedure in Commission Regulation (EC) No 1565/2000. From the in vitro...... substance [FL-no: 14.051] no intake data are available preventing it from being evaluated through the Procedure. The remaining 18 substances were evaluated through a stepwise approach that integrates information on structure-activity relationships, intake from current uses, toxicological threshold...... intake, estimated on the basis of the MSDI approach. For the remaining substance [FL-no: 14.052] additional toxicity data are required. Besides the safety assessment of these flavouring substances, the specifications for the materials of commerce have also been considered and for two substances...

  14. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 10, Revision 3 (FGE.10Rev3): Aliphatic primary and secondary saturated and unsaturated alcohols, aldehydes, acetals, carboxylic acids and esters containing

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 63 flavouring substances in the Flavouring Group Evaluation 10, including additional two substances in this Revision 3, using the Procedure in Commission...... threshold of concern, and available data on metabolism and toxicity. The Panel concluded that the 62 substances do not give rise to safety concerns at their levels of dietary intake, estimated on the basis of the MSDI approach. Besides the safety assessment of these flavouring substances, the specifications...... for the materials of commerce have also been considered. For four substances evaluated through the Procedure, the stereoisomeric composition has not been specified sufficiently....

  15. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 301 (FGE.301): A sulphur substituted pyrimidin-derivative and its hydrochloride salt

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate two flavouring substances, 4-amino-5,6-dimethylthieno[2,3-d]pyrimidin-2(1H)-one [FL-no: 16.116] and 4-amino-5,6-dimethylthieno[2,3-d]pyrimidin-2(1H...... on structure-activity relationships, intake from current uses, toxicological threshold of concern, and available data on metabolism and toxicity. The Panel concluded that the two substances [FL-no: 16.116 and 16.120] do not give rise to safety concerns at their levels of dietary intake, estimated on the basis...

  16. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Flavouring Group Evaluation 46, Revision 1 (FGE.46Rev1): Ammonia and three ammonium salts from chemical group 30

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Scientific Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (the Panel) was asked to provide scientific advice to the Commission on the implications for human health of chemically defined flavouring substances used in or on foodstuffs in the Member States. In particular...... in a wide range of food items up to very high amounts. Hydrogen sulphide is also reported to occur naturally in a wide range of food items. In its evaluation, the Panel as a default used the “Maximised Survey-derived Daily Intake” (MSDI) approach to estimate the per capita intakes of the flavouring...... substances in Europe. However, when the Panel examined the information provided by the European Flavouring Industry on the use levels in various foods, it appeared obvious that the MSDI approach in a number of cases would grossly underestimate the intake by regular consumers of products flavoured at the use...

  17. Biofuel cells based on direct enzyme-electrode contacts using PQQ-dependent glucose dehydrogenase/bilirubin oxidase and modified carbon nanotube materials.

    Science.gov (United States)

    Scherbahn, V; Putze, M T; Dietzel, B; Heinlein, T; Schneider, J J; Lisdat, F

    2014-11-15

    Two types of carbon nanotube electrodes (1) buckypaper (BP) and (2) vertically aligned carbon nanotubes (vaCNT) have been used for elaboration of glucose/O2 enzymatic fuel cells exploiting direct electron transfer. For the anode pyrroloquinoline quinone dependent glucose dehydrogenase ((PQQ)GDH) has been immobilized on [poly(3-aminobenzoic acid-co-2-methoxyaniline-5-sulfonic acid), PABMSA]-modified electrodes. For the cathode bilirubin oxidase (BOD) has been immobilized on PQQ-modified electrodes. PABMSA and PQQ act as promoter for enzyme bioelectrocatalysis. The voltammetric characterization of each electrode shows current densities in the range of 0.7-1.3 mA/cm(2). The BP-based fuel cell exhibits maximal power density of about 107 µW/cm(2) (at 490 mV). The vaCNT-based fuel cell achieves a maximal power density of 122 µW/cm(2) (at 540 mV). Even after three days and several runs of load a power density over 110 µW/cm(2) is retained with the second system (10mM glucose). Due to a better power exhibition and an enhanced stability of the vaCNT-based fuel cells they have been studied in human serum samples and a maximal power density of 41 µW/cm(2) (390 mV) can be achieved. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Contact interactions, stress and material symmetry

    Directory of Open Access Journals (Sweden)

    Podio-Guidugli P.

    2002-01-01

    Full Text Available An argument is given intimating that, for nonsimple materials, the concepts of contact interaction and material symmetry, as well as the bridging concept of stress, should be carefully revised and generalized. .

  19. Biocatalytic material comprising multilayer enzyme coated fiber

    Science.gov (United States)

    Kim, Jungbae [Richland, WA; Kwak, Ja Hun [Richland, WA; Grate, Jay W [West Richland, WA

    2009-11-03

    The present invention relates generally to high stability, high activity biocatalytic materials and processes for using the same. The materials comprise enzyme aggregate coatings having high biocatalytic activity and stability useful in heterogeneous environment. These new materials provide a new biocatalytic immobilized enzyme system with applications in bioconversion, bioremediation, biosensors, and biofuel cells.

  20. Contact angle of unset elastomeric impression materials.

    Science.gov (United States)

    Menees, Timothy S; Radhakrishnan, Rashmi; Ramp, Lance C; Burgess, John O; Lawson, Nathaniel C

    2015-10-01

    Some elastomeric impression materials are hydrophobic, and it is often necessary to take definitive impressions of teeth coated with some saliva. New hydrophilic materials have been developed. The purpose of this in vitro study was to compare contact angles of water and saliva on 7 unset elastomeric impression materials at 5 time points from the start of mixing. Two traditional polyvinyl siloxane (PVS) (Aquasil, Take 1), 2 modified PVS (Imprint 4, Panasil), a polyether (Impregum), and 2 hybrid (Identium, EXA'lence) materials were compared. Each material was flattened to 2 mm and a 5 μL drop of distilled water or saliva was dropped on the surface at 25 seconds (t0) after the start of mix. Contact angle measurements were made with a digital microscope at initial contact (t0), t1=2 seconds, t2=5 seconds, t3=50% working time, and t4=95% working time. Data were analyzed with a generalized linear mixed model analysis, and individual 1-way ANOVA and Tukey HSD post hoc tests (α=.05). For water, materials grouped into 3 categories at all time-points: the modified PVS and one hybrid material (Identium) produced the lowest contact angles, the polyether material was intermediate, and the traditional PVS materials and the other hybrid (EXA'lence) produced the highest contact angles. For saliva, Identium, Impregum, and Imprint 4 were in the group with the lowest contact angle at most time points. Modified PVS materials and one of the hybrid materials are more hydrophilic than traditional PVS materials when measured with water. Saliva behaves differently than water in contact angle measurement on unset impression material and produces a lower contact angle on polyether based materials. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  1. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2016. Scientific opinion on Flavouring Group Evaluation 313, (FGE.313): α,β-unsaturated 3(2H)-furanone derivatives from chemical group 13

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Nørby, Karin Kristiane

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of EFSA was requested to evaluate three flavouring substances, 2,5-dimethyl-4-ethoxyfuran-3(2H)-one [FL-no: 13.117], 2,5-dimethylfuran-3(2H)-one [FL-no: 13.119] and 4-Acetyl-2,5-dimethylfuran-3(2H)-one [FL-no: 13......–activity relationships, intake from current uses, toxicological threshold of concern, and available data on metabolism and toxicity. The Panel concluded that the two flavouring substances [FL-no: 13.117, 13.119] do not give rise to safety concerns at their level of dietary intake, estimated on the basis of the Maximised...... Survey-derived Daily Intake (MSDI) approach. For the flavouring substance [FL-no: 13.175], toxicity data are required. Besides the safety assessment of the flavouring substance, the specifications for the materials of commerce have also been considered. Adequate specifications including complete purity...

  2. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 11, Revision 2 (FGE.11Rev2): Aliphatic dialcohols, diketones, and hydroxyketones from chemical groups 8 and 10

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Scientific Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (the Panel) was asked to provide scientific advice to the Commission on the implications for human health of chemically defined flavouring substances used in or on foodstuffs in the Member States. In particular......, the Panel was requested to evaluate 12 flavouring substances in the Flavouring Group Evaluation 11, Revision 2 (FGE.11Rev2), using the Procedure as referred to in the Commission Regulation (EC) No 1565/2000. These 12 flavouring substances belong to chemical group 10, Annex I of the Commission Regulation (EC...... is a tertiary alcohol) [FL-no: 07.097, 07.165 and 07.184] all belonging to chemical groups 8 and 10. One of the 12 candidate substances possesses four chiral centres [FL-no: 06.134] two possesses two chiral centres [FL-no: 02.133 and 07.168] and four substances possesses one chiral centre [FL-no: 07.097, 07...

  3. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Ai ds (CEF); Scientific Opinion on Flavouring Group Evaluation 208 (FGE.208): Consideration of genotoxicity data on representatives for 10 alicyclic aldehydes with the α , β - unsaturation in ring / side - chain

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Binderup, Mona-Lise; Lund, Pia

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate the genotoxic potential of one flavouring substance from subgroup 2.2 of FGE.19 in the Flavouring Group Evaluation 208. The Flavour Industry has provided a...

  4. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 226 (FGE.226): Consideration of genotoxicity data on one α,β-unsaturated aldehyde from chemical subgroup 1.1.1(b) of FGE.19 by EFSA

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate the genotoxic potential of one flavouring substance from subgroup 1.1.1(b) of FGE.19 in the Flavouring Group Evaluation 226. The Flavour Industry has provi...

  5. EFSA CEF Panel (EFSA Panel on Fo od Contact Materials, Enzymes, Flavourings and Proce ssing Aids), 2015. Scientific Opinion on Flavouring Group Evalua tion 09, Revision 6 (FGE.09Rev6): Secondary alicyclic saturated and unsaturated alcohols, ketones and esters containing secondary alicyclic alcohols

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Nørby, Karin Kristiane

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 22 flavouring substances in the Flavouring Group Evaluation 9, Revision 6, using the Procedure in Commission Regulation (EC) No 1565/2000. None of the subs...

  6. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2013. Scientific Opinion on Flavouring Group Evaluation 220, Revision 2 (FGE.220Rev1): α,β-Unsaturated ketones and precursors from chemical subgroup 4.4 of FGE.19: 3(2H)-Furanones

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Binderup, Mona-Lise; Lund, Pia

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate the genotoxic potential of 10 flavouring substances from subgroup 4.4 of FGE.19 in the Flavouring Group Evaluation 220 (FGE.220). FGE.220 is subdivided int...

  7. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2014. Scientific Opinion on Flavouring Group Evaluation 213, Revision 1 (FGE.213Rev1): Consideration of genotoxic potential for α , β -Unsaturated Alicyclic ketones and precursors from chemical subgroup

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Binderup, Mona-Lise; Lund, Pia

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate the genotoxic potential of 26 flavouring substances from subgroup 2.7 of FGE.19 in the Flavouring Group Evaluation 213. In the first version of FGE.213 the...

  8. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2013. Scientific Opinion on Flavouring Group Evaluation 217, Revision 1 (FGE.217Rev1). Consideration of genotoxic potential for α,β-Unsaturated ketones and precursors from chemical subgroup 4.1 of FGE

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Binderup, Mona-Lise; Lund, Pia

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate the genotoxic potential of 12 flavouring substances from subgroup 4.1 of FGE.19 in the Flavouring Group Evaluation 217 (FGE.217). In FGE.217, 6-methylcouma...

  9. EFSA CEF Penal (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2014. Scientific Opinion on Flavouring Group Evaluation 212, Revision 2 (FGE.212Rev2): α,β-Unsaturated alicyclic ketones and precursors from chemical subgroup 2.6 of FGE.19

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Binderup, Mona-Lise; Lund, Pia

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate the genotoxic potential of 24 flavouring substances from subgroup 2.6 of FGE.19 in the Flavouring Group Evaluation 212, Revision 2. The Panel concluded in ...

  10. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 9, Revision 3 (FGE.09Rev3): Secondary alicyclic saturated and unsaturated alcohols, ketones and esters containing secondary alicyclic alcohols from chemical group

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 17 flavouring substances in the Flavouring Group Evaluation 9, Revision 3, using the Procedure in Commission Regulation (EC) No 1565/2000. None of the subs...

  11. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 9, Revision 4 (FGE.09Rev4): Secondary alicyclic saturated and unsaturated alcohols, ketones and esters containing secondary alicyclic alcohols from chemical group

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 21 flavouring substances in the Flavouring Group Evaluation 9, Revision 4, using the Procedure in Commission Regulation (EC) No 1565/2000. The present revi...

  12. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 7, Revision 4 (FGE.07Rev4): Saturated and unsaturated aliphatic secondary alcohols, ketones and esters of secondary alcohols and saturated linear or branched

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 49 flavouring substances in the Flavouring Group Evaluation 07, including additional five substances in this Revision 4, using the Procedure in Commission ...

  13. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2014. Scientific Opinion on Flavouring Group Evaluation 9, Revision 5 (FGE.09Rev5): Secondary alicyclic saturated and unsaturated alcohols, ketones and esters containing secondary alicyclic alcohols

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Frandsen, Henrik Lauritz; Nørby, Karin Kristiane

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 21 flavouring substances in the Flavouring Group Evaluation 9, Revision 5, using the Procedure in Commission Regulation (EC) No 1565/2000. The present revi...

  14. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2015. Scientific Opinion on Flavouring Group Evaluation 213, Revision 2 (FGE.213Rev2): Consideration of genotoxic potential for α,β-unsaturated alicyclic ketones and precursors from chemical subgroup 2

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Nørby, Karin Kristiane

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF Panel) of the European Food Safety Authority (EFSA) was requested to evaluate the genotoxic potential of 26 flavouring substances from subgroup 2.7 of FGE.19 in Flavouring Group Evaluation (FGE) 213. In the first v...

  15. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2014. Scientific Opinion on Flavouring Group Evaluation 210, Revision 1 (FGE.210Rev1): Consideration of genotoxic potential for α,β-unsaturated alicyclic ketones and precursors from chemical subgroup 2

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Binderup, Mona-Lise; Lund, Pia

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate the genotoxic potential of 13 flavouring substances in Flavouring Group Evaluation 210 (FGE.210) and one additional substance [FL-no: 07.225] in this revis...

  16. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 13, Revision 2 (FGE.13 Rev2) Furfuryl and furan derivatives with and without additional side-chain substituents and heteroatoms from chemical group 14

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 27 flavouring substances in the Flavouring Group Evaluation 13, Revision 2, using the Procedure in Commission Regulation (EC) No 1565/2000. Three...... of commerce have also been considered. Adequate specifications including complete purity criteria and identity for the materials of commerce have been provided for all 24 flavouring substances evaluated through the Procedure....

  17. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 18, Revision 2 (FGE.18Rev2): Aliphatic, alicyclic and aromatic saturated and unsaturated tertiary alcohols, aromatic tertiary alcohols and their esters from

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 32 flavouring substances in the Flavouring Group Evaluation 18, Revision 2, using the Procedure in Commission Regulation (EC) No 1565/2000. None of the sub......The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 32 flavouring substances in the Flavouring Group Evaluation 18, Revision 2, using the Procedure in Commission Regulation (EC) No 1565/2000. None...... of the substances were considered to have genotoxic potential. The substances were evaluated through a stepwise approach (the Procedure) that integrates information on structure-activity relationships, intake from current uses, toxicological threshold of concern, and available data on metabolism and toxicity......, the specifications for the materials of commerce have also been considered and for six substances information is lacking....

  18. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 08, Revision 5 (FGE.08Rev5): Aliphatic and alicyclic mono-, di-, tri-, and polysulphides with or without additional oxygenated functional groups from chemical

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 80 flavouring substances in the Flavouring Group Evaluation 08, Revision 4, using the Procedure in Commission Regulation (EC) No 1565/2000. Since the publi......The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 80 flavouring substances in the Flavouring Group Evaluation 08, Revision 4, using the Procedure in Commission Regulation (EC) No 1565/2000. Since...... approach that integrates information on the structure-activity relationships, intake from current uses, toxicological threshold of concern, and available data on metabolism and toxicity. The Panel concluded that 59 substances do not give rise to safety concerns at their levels of dietary intake, estimated...... substances, the specifications for the materials of commerce have also been considered and for three substances, evaluated through the Procedure, information on the specifications is lacking....

  19. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 8, Revision 3 (FGE.08Rev3): Aliphatic and alicyclic mono-, di-, tri-, and polysulphides with or without additional oxygenated functional groups from chemical

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 70 flavouring substances in the Flavouring Group Evaluation 08, Revision 3, using the Procedure in Commission Regulation (EC) No 1565/2000. For the substan......The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 70 flavouring substances in the Flavouring Group Evaluation 08, Revision 3, using the Procedure in Commission Regulation (EC) No 1565......-activity relationships, intake from current uses, toxicological threshold of concern, and available data on metabolism and toxicity. The Panel concluded that 48 substances do not give rise to safety concerns at their levels of dietary intake, estimated on the basis of the MSDI approach. For the remaining fourteen......, the specifications for the materials of commerce have also been considered and for eightteen substances information on specifications is lacking....

  20. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific O pinion Flavouring Group Evaluation 23, Revision 4 (FGE.23Rev4): Aliphatic, alicyclic and aromatic ethers including anisole derivatives from chemical groups 15, 16, 22, 26 and 30

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Binderup, Mona-Lise; Frandsen, Henrik Lauritz

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 21 flavouring substances in the Flavouring Group Evaluation 23, Revision 4, using the Procedure in Commission Regulation (EC) No 1565/2000. This revision i...... also been considered. Specifications including complete purity criteria and identity for the materials of commerce have been provided for all 21 candidate substances. © European Food Safety Authority, 2013......The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 21 flavouring substances in the Flavouring Group Evaluation 23, Revision 4, using the Procedure in Commission Regulation (EC) No 1565/2000. This revision...

  1. Dynamic frictional contact for elastic viscoplastic material

    Directory of Open Access Journals (Sweden)

    Kenneth L. Kuttler

    2007-05-01

    Full Text Available Using a general theory for evolution inclusions, existence and uniqueness theorems are obtained for weak solutions to a frictional dynamic contact problem for elastic visco-plastic material. An existence theorem in the case where the friction coefficient is discontinuous is also presented.

  2. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 21, Revision 2 (FGE.21Rev2): Thiazoles, thiophene, thiazoline and thienyl derivatives from chemical group 29. Miscellaneous substances from chemical group 30

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 56 flavouring substances in the Flavouring Group Evaluation 21, Revision 2, using the Procedure in Commission Regulation (EC) No 1565/2000. Seven...... of commerce have also been considered. For two substances are an identity test lacking and for one has the stereoisomeric composition to be specified....

  3. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2013. Scientific Opinion on Flavouring Group Evaluation 216, Revision 1 (FGE.216Rev1). Consideration of genotoxic potential for α,β-unsaturated 2-Phenyl -2-Alkenals from Subgroup 3.3 of FGE.19

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Binderup, Mona-Lise; Lund, Pia

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate the genotoxic potential of five flavouring substances from subgroup 3.3 of FGE.19. In the Flavouring Group Evaluation 216 (FGE.216) additional genotoxicity...... of animals treated with 2-phenylcrotonaldehyde. Moreover, since the substance was genotoxic only without metabolic activation, it appears necessary to prove the absence of genotoxic effect locally in the gastro intestinal system using the Comet assay....

  4. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 23, Revision 3 (FGE.23Rev3): Aliphatic, alicyclic and aromatic ethers including anisole derivatives from chemical groups 15, 16, 22, 26 and 30

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 20 flavouring substances in the Flavouring Group Evaluation 23, Revision 3, using the Procedure in Commission Regulation (EC) No 1565/2000. None...... of the MSDI approach. Besides the safety assessment of these flavouring substances, the specifications for the materials of commerce have also been considered. Specifications including complete purity criteria and identity for the materials of commerce have been provided for all 20 candidate substances....

  5. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2015. Scientific Opinion on Flavouring Group Evaluation 78, Revision 2 (FGE.78Rev2): Consideration of aliphatic and alicyclic and aromatic hydrocarbons evaluated by JECFA (63rd meeting) structurally

    DEFF Research Database (Denmark)

    Nørby, Karin Kristiane; Beltoft, Vibe Meister

    evaluated through a stepwise approach that integrates information on structure-activity relationships, intake from current uses, toxicological threshold of concern, and available data on metabolism and toxicity. The specifications for the materials of commerce are adequate for all substances. The Panel......The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to consider evaluations of flavouring substances assessed since 2000 by the Joint FAO/WHO Expert Committee on Food Additives (the JECFA), and to decide whether further...

  6. Phospholipids and their degrading enzyme in the tears of soft contact lens wearers.

    Science.gov (United States)

    Yamada, Masakazu; Mochizuki, Hiroshi; Kawashima, Motoko; Hata, Seiichiro

    2006-12-01

    Low tear phospholipids levels are associated with tear film instability in soft contact lens wearers. We assayed levels of phospholipids and their degrading enzyme secretory phospholipase A2 (sPLA2) both in tears and deposited on contact lenses composed of 2 hydrophilic materials after 1 day of routine use. Polymacon (Medalist; FDA group 1, low water/nonionic) and Etafilcon A (One Day Acuvue; group 4, high water/ionic) contact lenses were worn for 12 hours by 16 experienced contact lens wearers. Phospholipids in tear fluids and deposited on contact lenses were estimated by phosphorus determination with ammonium molybdate through enzymatic digestion. Double-antibody sandwich ELISA was used to determine group IIa sPLA2 concentrations, and sPLA2 activity was assayed using 1,2-diheptanoyl thio-phosphatidylcholine as substrate. Phospholipids concentrations in tears with Polymacon and Etafilcon A were 186 +/- 39 and 162 +/- 33 microg/mL, respectively. The latter concentration was significantly lower than that observed in the same subjects when not wearing contact lenses (P = 0.0023). In tears, both group IIa sPLA2 concentrations and enzymatic activity remained unchanged, regardless of lens wearing. However, Etafilcon A (0.57 +/- 0.09 microg/lens) showed more group IIa sPLA2 deposition than Polymacon (0.01 +/- 0.01 microg/lens; P < 0.001). Furthermore, group IIa sPLA2 deposited on Etafilcon A but not on Polymacon lenses retained its enzymatic activity. Significant differences of group IIa sPLA2 deposition were found in the 2 lenses tested. Such deposition might induce phospholipid hydrolysis in tears and thereby promote tear film instability in hydrophilic contact lens wearers.

  7. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 20, Revision 3 (FGE.20Rev3): Benzyl alcohols, benzaldehydes, a related acetal, benzoic acids, and related esters from chemical groups 23 and 30

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to consider in this revision 3 of Flavouring Group Evaluation 20, the SCF Opinion on benzoic acid. Furthermore information on stereoisomeric composition for two...... Regulation (EC) No 1565/2000. None of the substances were considered to have genotoxic potential. The substances were evaluated through a stepwise approach (the Procedure) that integrates information on structure-activity relationships, intake from current uses, toxicological threshold of concern...

  8. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2016. Scientific opinion on Flavouring Group Evaluation 400 (FGE.400): 3-(1- ((3,5-dimethylisoxazol-4-yl)methyl)-1H-pyrazol-4-yl)-1-(3-hydroxybenzyl)imidazolidine-2,4-dione

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Nørby, Karin Kristiane

    modifier in specific categories of food. There is no safety concern with respect to genotoxicity. A 90-day dietary administration study in rats showed no adverse effects for doses up to 100 mg/kg body weight (bw) per day, providing an adequate margin of safety. Developmental toxicity was not observed...... for various foods in different food categories.......The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF) of EFSA was requested to deliver a scientific opinion on the implications for human health of the flavouring substance 3-(1-((3,5-dimethylisoxazol-4-yl)methyl)-1H-pyrazol-4-yl)-1-(3-hydroxybenzyl)imidazolidine-2...

  9. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids) , 2016. Scientific Opinion on Flavouring Group Evaluation 90, Revision 1 (FGE.90Rev1): consideration of six substances evaluated by JECFA (68th meeting) structurally related to aliphatic, alicyclic and aromatic saturated and unsaturated tertiary alcohols, aromatic tertiary alcohols and their esters evaluated by EFSA in FGE.18Rev1 and FGE.75Rev1

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Nørby, Karin Kristiane

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of EFSA was requested to consider evaluations of flavouring substances assessed since 2000 by the Joint FAO/WHO Expert Committee on Food Additives (the JECFA), and to decide whether further evaluation is necessary...... refined exposure estimation and to judge whether a re-evaluation according to the Procedure is needed....

  10. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 30, Revision 1 (FGE.30Rev1): 4-Prop-1-enylphenol and 2-methoxy-4-(prop- 1enyl)phenyl 3-methylbutyrate from chemical group 17

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate two flavouring substances in the Flavouring Group Evaluation 30, Revision 1, using the Procedure in Commission Regulation (EC) No 1565/2000. None of the su......The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate two flavouring substances in the Flavouring Group Evaluation 30, Revision 1, using the Procedure in Commission Regulation (EC) No 1565/2000. None...... of the substances were considered to have genotoxic potential. The two substances were evaluated through a stepwise approach that integrates information on structure-activity relationships, intake from current uses, toxicological threshold of concern, and available data on metabolism and toxicity. The Panel...... concluded that the two substances [FL-no: 04.097, 09.894] do not give rise to safety concerns at their levels of dietary intake, estimated on the basis of the MSDI approach. Besides the safety assessment of these flavouring substances, the specifications for the materials of commerce have also been...

  11. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 08, Revision 4 (FGE.08Rev4): Aliphatic and alicyclic mono-, di-, tri-, and polysulphides with or without additional oxygenated functional groups from chemical

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 80 flavouring substances in the Flavouring Group Evaluation 08, Revision 4, using the Procedure in Commission Regulation (EC) No 1565/2000. Since the publi......The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 80 flavouring substances in the Flavouring Group Evaluation 08, Revision 4, using the Procedure in Commission Regulation (EC) No 1565/2000. Since...... be estimated and accordingly the Panel concluded that the Procedure could not be applied to these four substances either. The remaining 71 substances were evaluated through a stepwise approach that integrates information on the structure-activity relationships, intake from current uses, toxicological threshold.......116, 12.120, 12.164, 12.167, 12.199, 15.007, 15.102 and 15.125 and 15.134], evaluated through the Procedure, no appropriate NOAEL was available and additional data are required. Besides the safety assessment of the flavouring substances, the specifications for the materials of commerce have also been...

  12. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2016 Scientific Opinion on Flavouring Group Evaluation 75, Revision 1 (FGE.75Rev1): Consideration of tetrahydrofuran derivatives evaluated by JECFA (63rd meeting) structurally related to tetrahydrofuran

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Nørby, Karin Kristiane

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF) of the EFSA was requested to consider evaluations of flavouring substances assessed since 2000 by the Joint FAO/WHO Expert Committee on Food Additives (the JECFA), and to decide whether further evaluation is neces......The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF) of the EFSA was requested to consider evaluations of flavouring substances assessed since 2000 by the Joint FAO/WHO Expert Committee on Food Additives (the JECFA), and to decide whether further evaluation...... for anhydrolinalool oxide (5) [FL-no: 13.097]. The substances were evaluated through a stepwise approach that integrates information on structure-activity relationships, intake from current uses, toxicological threshold of concern, and available data on metabolism and toxicity. The JECFA concluded all the 11...... with the JECFA conclusion ‘No safety concern at estimated level of intake as flavouring substances’ based on the maximised survey-derived daily intake (MSDI) approach. The specifications for the materials of commerce have also been considered and for all 11 substances, the information is adequate....

  13. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 06, Revision 3 (FGE.06Rev3): Straight- and branched-chain aliphatic unsaturated primary alcohols, aldehydes, carboxylic acids, and esters from chemical groups 1

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 50 flavouring substances in the Flavouring Group Evaluation 6, Revision 3, using the Procedure in Commission Regulation (EC) No 1565/2000. None of the subs......The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 50 flavouring substances in the Flavouring Group Evaluation 6, Revision 3, using the Procedure in Commission Regulation (EC) No 1565/2000. None...... of the substances were considered to have genotoxic potential. The substances were evaluated through a stepwise approach (the Procedure) that integrates information on structure-activity relationships, intake from current uses, toxicological threshold of concern, and available data on metabolism and toxicity...... of these flavouring substances, the specifications for the materials of commerce have also been considered. For one substance [FL-no: 09.938] an identity test is missing and for two substances [FL-no: 05.226 and 09.950] the range of the specific gravity is too wide. Additional, the stereoisomeric mixture has not been...

  14. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2014. Scientific Opinion on lipase from a genetically modified strain of Aspergillus oryzae (strain NZYM-FL)

    DEFF Research Database (Denmark)

    Poulsen, Morten; Hallas-Møller, Torben; Binderup, Mona-Lise

    The food enzyme considered in this opinion is a lipase (triacylglycerol lipase; EC 3.1.1.3) produced with a genetically modified strain of Aspergillus oryzae. The genetic modifications do not raise safety concern. The food enzyme contains neither the production organism nor recombinant DNA...

  15. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2014. Scientific Opinion on Flavouring Group Evaluation 94, Revision 2 (FGE.94Rev2): Consideration of aliphatic amines and amides evaluated in an addendum to the group of aliphatic and aromatic amines

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Binderup, Mona-Lise; Frandsen, Henrik Lauritz

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to consider evaluations of flavouring substances assessed since 2000 by the Joint FAO/WHO Expert Committee on Food Additives (the JECFA), and to decide whether further......-(3,4-dimethoxyphenyl)-ethyl]-acrylamide [FL-no: 16.090]. The substances were evaluated through a stepwise approach that integrates information on structure-activity relationships, intake from current uses, toxicological threshold of concern and available data on metabolism and toxicity. The Panel agrees with JECFA...... conclusion “No safety concern at estimated levels of intake as flavouring substances” based on the MSDI approach for all substances considered in this FGE. Besides the safety assessment of these flavouring substances, the specifications for the materials of commerce have been considered and for all 12...

  16. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2015. Scientific Opinion on Flavouring Group Evaluation 86, Revision 2 (FGE.86Rev2): Consideration of aliphatic and arylalkyl amines and amides evaluated by JECFA (65th meeting)

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Nørby, Karin Kristiane

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to consider evaluations of flavouring substances assessed since 2000 by the Joint FAO/WHO Expert Committee on Food Additives (JECFA), and to decide whether further......-no: 14.003] and deca-(2E,4E)-dienoic acid isobutyl-amide [FL-no: 16.091]. The substances were evaluated through a stepwise approach that integrates information on structure-activity relationships, intake from current uses, toxicological thresholds of concern and available data on metabolism and toxicity...... for the materials of commerce have also been considered and for all 30 substances, the information is adequate....

  17. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2013. Scientific Opinion on Flavouring Group Evaluation 12, Revision 4 (FGE.12Rev4): primary saturated or unsaturated alicyclic alcohols, aldehydes, acids and esters from chemical groups 1 and 7

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Binderup, Mona-Lise; Frandsen, Henrik Lauritz

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 12 flavouring substances in Flavouring Group Evaluation 12, Revision 4 (FGE.12Rev4), including two additional substances, using the Procedure in Commission...... (the Procedure) that integrates information on structure–activity relationships, intake from current uses and the toxicological threshold of concern and available data on metabolism and toxicity. The Panel concluded that none of the 12 substances [FL-nos: 02.134, 02.186, 02.216, 02.217, 05.157, 05.......182, 05.183, 05.198, 08.135, 09.342, 09.670 and 09.829] gives rise to safety concerns at their levels of dietary intake, estimated on the basis of the maximised survey-derived daily intake approach. Besides the safety assessment of these flavouring substances, the specifications for the materials...

  18. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2013. Scientific Opinion on Flavouring Group Evaluation 73, Revision 2 (FGE.73Rev2). Consideration of alicyclic primary alcohols, aldehydes, acids and related esters evaluated by JECFA (59th meeting

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Binderup, Mona-Lise; Frandsen, Henrik Lauritz

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to consider evaluations of flavouring substances assessed since 2000 by the Joint FAO/WHO Expert Committee on Food Additives (the JECFA), and to decide whether further...... uses, toxicological threshold of concern, and available data on metabolism and toxicity. The Panel agrees with the application of the Procedure as performed by the JECFA for all 18 substances [FL-no: 02.114, 02.141, 05.098, 05.104, 05.112, 05.119, 05.123, 08.034, 08.060, 08.067, 09.028, 09.034, 09...... for the materials of commerce have also been considered and for all 18 substances, the information is adequate....

  19. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2014. Scientific Opinion on Flavouring Group Evaluation 91, Re vision 2 (FGE.91Rev2): Consid eration of simple aliphatic and aromatic sulphides and thiols evaluated by the JECFA (53rd and 68th meetings

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Binderup, Mona-Lise; Frandsen, Henrik Lauritz

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to consider evaluations of flavouring substances assessed since 2000 by the Joint FAO/WHO Expert Committee on Food Additives (the JECFA), and to decide whether further...... that integrates information on structure-activity relationships, intake from current uses, toxicological threshold of concern, and available data on metabolism and toxicity. For 36 substances considered in this FGE the Panel concluded that they would pose “No safety concern at estimated levels of intake...... related substance. Besides the safety assessment of these flavouring substances, the specifications for the materials of commerce have also been considered and for all 44 substances, the information is adequate. For candidate substance 3-(methylthio)heptenal [FL-no: 12.273], which contains 5 to7 % of an α...

  20. EFSA Panel on Food Contact Material, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 73, Revision 1: Consideration of alicyclic primary alcohols, aldehydes, acids and related esters evaluated by JECFA (59th meeting) structurally related to primary

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to consider evaluations of flavouring substances assessed since 2000 by the Joint FAO/WHO Expert Committee on Food Additives (the JECFA), and to decide whether further...... substance compared to the previous version. The substances were evaluated through a stepwise approach that integrates information on structure-activity relationships, intake from current uses, toxicological threshold of concern, and available data on metabolism and toxicity. The Panel agrees...... levels of intake as flavouring substances” based on the MSDI approach. Besides the safety assessment of these flavouring substances, the specifications for the materials of commerce have also been considered and for all 16 substances, the information is adequate....

  1. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2014. Scientific Opinion on Flavouring Group Evaluation 74, Revision 3 (FGE.74Rev3): Consideration of Simple Aliphatic Sulphides and Thiols evaluated by the JECFA (53rd and 61st meeting) Structurally

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Binderup, Mona-Lise; Frandsen, Henrik Lauritz

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to consider evaluations of flavouring substances assessed since 2000 by the Joint FAO/WHO Expert Committee on Food Additives (the JECFA), and to decide whether further...... that integrates information on structure-activity relationships, intake from current uses, toxicological threshold of concern, and available data on metabolism and toxicity. For nine substances [FL-no: 12.088, 12.179, 12.198, 12.212, 12.238, 12.239, 12.255, 12.257 and 12.291] considered in this FGE, the Panel...... concluded that they would pose “No safety concern at estimated levels of intake as flavouring substances” based on the MSDI approach. Besides the safety assessment of these flavouring substances, the specifications for the materials of commerce have also been considered for the substances evaluated through...

  2. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2013. Scientific Opinion on Flavouring Group Evaluation 72, Revision 1 (FGE.72Rev1): Consideration of aliphatic, branched-chain saturated and unsaturated alcohols, aldehydes, acids, and related esters

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Binderup, Mona-Lise; Frandsen, Henrik Lauritz

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to consider evaluations of flavouring substances assessed since 2000 by the Joint FAO/WHO Expert Committee on Food Additives (the JECFA), and to decide whether further...... threshold of concern, and available data on metabolism and toxicity. The Panel agrees with the application of the Procedure as performed by the JECFA for all 23 substances considered in this FGE and agrees with the JECFA conclusion, “No safety concern at estimated levels of intake as flavouring substances......” based on the MSDI approach. Besides the safety assessment of these flavouring substances, the specifications for the materials of commerce have also been considered and for all 23 substances, the information is adequate...

  3. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2014. Scientific Opinion on Flavouring Group Evaluation 73, Revision 3 (FGE.73Rev3): Consideration of alicyclic alcohols, aldehydes, acids and related esters evaluated by JECFA (59th and 63rd meeting

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Frandsen, Henrik Lauritz; Nørby, Karin Kristiane

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to consider evaluations of flavouring substances assessed since 2000 by the Joint FAO/WHO Expert Committee on Food Additives (the JECFA), and to decide whether further...... of one additional substance, beta-ionyl acetate [FL-no: 09.305] cleared for genotoxicity concern in FGE.213Rev1. The substances were evaluated through a stepwise approach that integrates information on structure-activity relationships, intake from current uses, toxicological threshold of concern.......712] considered in this FGE and agrees with the JECFA conclusion, “No safety concern at estimated levels of intake as flavouring substances” based on the MSDI approach. Besides the safety assessment of these flavouring substances, the specifications for the materials of commerce have also been considered...

  4. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 06, Revision 2 (FGE.06Rev2): Straight- and branched-chain aliphatic unsaturated primary alcohols, aldehydes, carboxylic acids, and esters from chemical groups 1

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The European Food Safety Authority (EFSA) asked the Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (the Panel) to provide scientific advice to the Commission on the implications for human health of chemically defined flavouring substances used in or on foodstuffs...... in the commercial flavouring material. Forty-six candidate substances are classified into structural class I. The remaining two substances [FL-no: 05.143 and 09.884] are classified into structural class II. Thirty-eight of the flavouring substances in the present group have been reported to occur naturally...... in a wide range of food items. According to the default MSDI approach, the 48 flavouring substances in this group have intakes in Europe from 0.001 to 120 microgram/capita/day, which are below the thresholds of concern value for both structural class I (1800 microgram/person/day) and structural class II...

  5. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 3, Revision 2 (FGE.03Rev2): Acetals of branched- and straight-chain aliphatic saturated primary alcohols and branched- and straight-chain saturated or unsaturated

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate one flavouring substance, acetaldehyde ethyl isopropyl acetal [FL-no: 06.137], structurally related to the 58 flavouring substances in the Flavouring Group...... on structure-activity relationships, intake from current uses, toxicological threshold of concern, and available data on metabolism and toxicity. The Panel concluded as for the other already evaluated substances that the substance [FL-no: 06.137] do not give rise to safety concern at its level of dietary...... intake, estimated on the basis of the MSDI approach. Besides the safety assessment of this flavouring substance, the specifications for the materials of commerce have also been considered, and since the publication of FGE.03Rev1 additional information on chirality on 30 substances is made available...

  6. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2014. Scientific Opinion on xylanase from a genetically modified strain of Aspergillus oryzae (strain NZYM-FB)

    DEFF Research Database (Denmark)

    Poulsen, Morten; Binderup, Mona-Lise; Hallas-Møller, Torben

    . The xylanase is intended to be used in a number of food manufacturing processes, such as starch processing, beverage alcohol (distilling), brewing, baking and other cereal based processes. The dietary exposure was assessed according to the Budget method. The food enzyme did not induce gene mutations...

  7. EFSA Panel on food contact materials, enzymes, flavourings and processing aids (CEF); Scientific Opinion on Flavouring Group Evaluation 23, Revision 2 (FGE.23Rev2): Aliphatic, alicyclic and aromatic ethers including anisole derivatives from chemical groups 15, 16, 22, 26 and 30

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The European Food Safety Authority (EFSA) asked the Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (the Panel) to provide scientific advice to the Commission on the implications for human health of chemically defined flavouring substances used in or on foodstuffs...... in the Member States. In particular, the Panel was requested to evaluate 19 flavouring substances in the Flavouring Group Evaluation 23, Revision 2 (FGE.23Rev2), using the Procedure as referred to in the Commission Regulation (EC) No 1565/2000. These 19 flavouring substances belong to chemical groups 15, 16, 22......-no: 03.022] Industry has informed that it occurs as a mixture of E- & Z-isomers, however, the composition of the mixture has to be specified. Two of the flavouring substances are classified into structural class I, seven are classified into structural class II and 10 are classified into structural class...

  8. EFSA Panel on Food Contact Materials , Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 224 (FGE.224): Consideration of genotoxic potential for two α,β - unsaturated thiophenes from subgroup 5.2 of FGE.19 by EFSA

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Binderup, Mona-Lise; Lund, Pia

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate the genotoxic potential of two flavouring substances from subgroup 5.2 of FGE.19 in the Flavouring Group Evaluation 224 (FGE.224). The Flavour Industry has...... provided additional genotoxicity studies for one of the two substances in FGE.224, namely 5-methyl-2-thiophenecarbaldehyde [FL-no: 15.004]. The data requested by EFSA for the other substance, 3-acetyl-2,5-dimethylthiophene [FL-no: 15.024] of FGE.224 will be provided subsequently according to the Flavour...... are still pending and no conclusion could be drawn in the present FGE. © European Food Safety Authority, 2013...

  9. Ohmic contacts to InN-based materials

    Directory of Open Access Journals (Sweden)

    Sai P. O.

    2016-10-01

    Full Text Available The key aspects of ohmic contact formation to InN-based materials were investigated. Detailed analysis of studies conducted over the past three decades, allows determining the basic principles of such contacts. The contact structure properties and optimal conditions for them are presented. Different types of metallization are considered, the advantages and disadvantages of each are determined, including the basic requirements that such contact must meet. There is emphasis on the using multilayer metallization with the barrier layers. In the case of the InAlN/GaN systems, the general approaches of forming ohmic contacts were considered.

  10. Bias dependent specic contact resistance of phase change material to metal contacts

    NARCIS (Netherlands)

    Roy, Deepu; in 't Zandt, Micha; Wolters, Robertus A.M.

    2010-01-01

    Knowledge of contact resistance of phase change materials (PCM) to metal electrodes is important for scaling, device modeling and optimization of phase change random access memory (PCRAM) cells. In this article, we report the systematic determination of the speci_c contact resistance (_c) with

  11. Contact materials for nanowire devices and nanoelectromechanical switches

    KAUST Repository

    Hussain, Muhammad Mustafa

    2011-02-01

    The impact of contact materials on the performance of nanostructured devices is expected to be signifi cant. This is especially true since size scaling can increase the contact resistance and induce many unseen phenomenon and reactions that greatly impact device performance. Nanowire and nanoelectromechanical switches are two emerging nanoelectronic devices. Nanowires provide a unique opportunity to control the property of a material at an ultra-scaled dimension, whereas a nanoelectromechanical switch presents zero power consumption in its off state, as it is physically detached from the sensor anode. In this article, we specifi cally discuss contact material issues related to nanowire devices and nanoelectromechanical switches.

  12. Radiation and enzyme degradation of cellulose materials

    International Nuclear Information System (INIS)

    Duchacek, V.

    1983-01-01

    The results are summed up of a study of the effect of gamma radiation on pure cellulose and on wheat straw. The irradiation of cellulose yields acid substances - formic acid and polyhydroxy acids, toxic malondialdehyde and the most substantial fraction - the saccharides xylose, arabinose, glucose and certain oligosaccharides. A ten-fold reduction of the level of cellulose polymerization can be caused by relatively small doses - (up to 250 kGy). A qualitative analysis was made of the straw before and after irradiation and it was shown that irradiation had no significant effect on the qualitative composition of the straw. A 48 hour enzyme hydrolysis of the cellulose and straw were made after irradiation and an economic evaluation of the process was made. Radiation pretreatment is technically and economically advantageous; the production of fodder using enzyme hydrolysis of irradiated straw is not economically feasible due to the high cost of the enzyme. (M.D.)

  13. Contact mechanics for layered materials with randomly rough surfaces.

    Science.gov (United States)

    Persson, B N J

    2012-03-07

    The contact mechanics model of Persson is applied to layered materials. We calculate the M function, which relates the surface stress to the surface displacement, for a layered material, where the top layer (thickness d) has different elastic properties than the semi-infinite solid below. Numerical results for the contact area as a function of the magnification are presented for several cases. As an application, we calculate the fluid leak rate for laminated rubber seals.

  14. Scientific Challenges in the Risk Assessment of Food Contact Materials

    DEFF Research Database (Denmark)

    Muncke, Jane; Backhaus, Thomas; Geueke, Birgit

    2017-01-01

    formed in the production processes. Several factors hamper effective RA for many FCMs, including a lack of information on chemical identity, inadequate assessment of hazardous properties, and missing exposure data. Companies make decisions about the safety of some food contact chemicals (FCCs) without......Food contact articles (FCAs) are manufactured from food contact materials (FCMs) that include plastics, paper, metal, glass, and printing inks. Chemicals can migrate from FCAs into food during storage, processing, and transportation. Food contact materials' safety is evaluated using chemical risk...... to enhance the safety of food contact articles. Based on our evaluation of the evidence, we conclude that current regulations are insufficient for addressing chemical exposures from FCAs. RA currently focuses on monomers and additives used in the manufacture of products, but it does not cover all substances...

  15. Numerical simulations of rough contacts between viscoelastic materials

    Science.gov (United States)

    Spinu, S.; Cerlinca, D.

    2017-08-01

    The durability of the mechanical contact is often plagued by surface-related phenomena like rolling contact fatigue, wear or crack propagation, which are linked to the important gradients of stress arising in the contacting bodies due to interaction at the asperity level. The semi-analytical computational approach adopted in this paper is based on a previously reported algorithm capable of simulating the contact between bodies with arbitrary limiting surfaces and viscoelastic behaviour, which is enhanced and adapted for the contact of real surfaces with microtopography. As steep slopes at the asperity level inevitably lead to localized plastic deformation at the tip of the asperities that are first brought into contact, the viscoelastic behaviour is amended by limiting the maximum value of the pressure on the contact area to that of the material hardness, according to the Tabor equation. In this manner, plasticity is considered in a simplified manner that assures the knowledge of the contact area and of the pressure distribution without estimation of the residual state. The main advantage of this approach is the preservation of the algorithmic complexity, allowing the simulation of very fine meshes capable of capturing particular features of the investigated contacting surface. The newly advanced model is expected to predict the contact specifics of rough surfaces as resulting from various manufacturing processes, thus assisting the design of durable machine elements using elastomers or rubbers.

  16. Airborne non-contact and contact broadband ultrasounds for frequency attenuation profile estimation of cementitious materials.

    Science.gov (United States)

    Gosálbez, J; Wright, W M D; Jiang, W; Carrión, A; Genovés, V; Bosch, I

    2018-08-01

    In this paper, the study of frequency-dependent ultrasonic attenuation in strongly heterogeneous cementitious materials is addressed. To accurately determine the attenuation over a wide frequency range, it is necessary to have suitable excitation techniques. We have analysed two kinds of ultrasound techniques: contact ultrasound and airborne non-contact ultrasound. The mathematical formulation for frequency-dependent attenuation has been established and it has been revealed that each technique may achieve similar results but requires specific different calibration processes. In particular, the airborne non-contact technique suffers high attenuation due to energy losses at the air-material interfaces. Thus, its bandwidth is limited to low frequencies but it does not require physical contact between transducer and specimen. In contrast, the classical contact technique can manage higher frequencies but the measurement depends on the pressure between the transducer and the specimen. Cement specimens have been tested with both techniques and frequency attenuation dependence has been estimated. Similar results were achieved at overlapping bandwidth and it has been demonstrated that the airborne non-contact ultrasound technique could be a viable alternative to the classical contact technique. Copyright © 2018 Elsevier B.V. All rights reserved.

  17. Migration of compounds from food contact materials and articles

    DEFF Research Database (Denmark)

    Petersen, Jens Højslev

    2003-01-01

    This chapter presents the different types of food contact/packaging materials (plastics, paper and cardboard, metals, glass, rubbers, lacquers and coatings) and discusses the EU legislation concerning the safety of using these materials. Case studies on the migration of lead, bisphenol A, bisphen...

  18. Investigation of contact allergy to dental materials by patch testing

    Directory of Open Access Journals (Sweden)

    Reena Rai

    2014-01-01

    Full Text Available Background: Dental products are widely used by patients and dental personnel alike and may cause problems for both. Dental materials could cause contact allergy with varying manifestations such as burning, pain, stomatitis, cheilitis, ulcers, lichenoid reactions localized to the oral mucosa in patients, and hand dermatitis in dental personnel. Patch testing with the dental series comprising commonly used materials can be used to detect contact allergies to dental materials. Aim: This study aimed to identify contact allergy among patients who have oral mucosal lesions after dental treatment and among dental personnel who came in contact with these materials. Materials and Methods: Twenty patients who had undergone dental procedures with symptoms of oral lichen planus, oral stomatitis, burning mouth, and recurrent aphthosis, were included in the study. Dental personnel with history of hand dermatitis were also included in the study. Patch testing was performed using Chemotechnique Dental Series and results interpreted as recommended by the International Contact Dermatitis Research Group (ICDRG. Results: Out of 13 patients who had undergone dental treatment/with oral symptoms, six patients with stomatitis, lichenoid lesions, and oral ulcers showed positive patch tests to a variety of dental materials, seven patients with ulcers had negative patch tests, seven dental personnel with hand dermatitis showed multiple allergies to various dental materials, and most had multiple positivities. Conclusion: The patch test is a useful, simple, noninvasive method to detect contact allergies among patients and among dental personnel dealing with these products. Long term studies are necessary to establish the relevance of these positive patch tests by eliminating the allergic substances, identifying clinical improvement, and substituting with nonallergenic materials.

  19. Flexible anodized aluminum oxide membranes with customizable back contact materials.

    Science.gov (United States)

    Nadimpally, B; Jarro, C A; Mangu, R; Rajaputra, S; Singh, V P

    2016-12-16

    Anodized aluminum oxide (AAO) membranes were fabricated using flexible substrate/carrier material. This method facilitates the use of AAO templates with many different materials as substrates that are otherwise incompatible with most anodization techniques. Thin titanium (Ti) and tungsten (W) layers were employed as interlayer materials. Titanium enhances adhesion. Tungsten not only helps eliminate the barrier layer but also plays a critical role in enabling the use of flexible substrates. The resulting flexible templates provide new, exciting opportunities in photovoltaic and other device applications. CuInSe 2 nanowires were electrochemically deposited into porous AAO templates with molybdenum (Mo) as the back contact material. The feasibility of using any material to form a contact with semiconductor nanowires has been demonstrated for the first time enabling new avenues in photovoltaic applications.

  20. Flexible anodized aluminum oxide membranes with customizable back contact materials

    Science.gov (United States)

    Nadimpally, B.; Jarro, C. A.; Mangu, R.; Rajaputra, S.; Singh, V. P.

    2016-12-01

    Anodized aluminum oxide (AAO) membranes were fabricated using flexible substrate/carrier material. This method facilitates the use of AAO templates with many different materials as substrates that are otherwise incompatible with most anodization techniques. Thin titanium (Ti) and tungsten (W) layers were employed as interlayer materials. Titanium enhances adhesion. Tungsten not only helps eliminate the barrier layer but also plays a critical role in enabling the use of flexible substrates. The resulting flexible templates provide new, exciting opportunities in photovoltaic and other device applications. CuInSe2 nanowires were electrochemically deposited into porous AAO templates with molybdenum (Mo) as the back contact material. The feasibility of using any material to form a contact with semiconductor nanowires has been demonstrated for the first time enabling new avenues in photovoltaic applications.

  1. Thermal characterization of radiation processed contact lens material

    International Nuclear Information System (INIS)

    Varshney, L.; Choughule, S.V.

    1998-01-01

    Differential scanning calorimetry (DSC), thermomechanical analysis (TMA) and thermogravimetry analysis (TGA) were used to characterize radiation processed contact lens gel material of 2-hydroxy ethyl methacrylate(HEMA). DSC revealed two types of water in the gels. DSC and TGA in combination were used to quantitate the percentage of different types of the water in the gel material. Temperature expansion coefficients values indicate more dimensions stability in the radiation processed lenses of similar water contents. (author)

  2. Effects of material properties on soft contact dynamics

    International Nuclear Information System (INIS)

    Khurshid, A.; Malik, M.A.; Ghafoor, A.

    2009-01-01

    The superiority of deformable human fingertips as compared to hard robot gripper fingers for grasping and manipulation has led to a number of investigations with robot hands employing elastomers or materials such as fluids or powders beneath a membrane at the fingertips. In this paper, to analyze the stability of dynamic control of an object grasped between two soft fingertips through a soft interface using the viscoelastic material between the manipulating fingers and a manipulated object is modeled through bond graph method (BGM). The fingers are made viscoelastic by using springs and dampers. Detailed bond graph modeling (BGM) of the contact phenomenon with two soft-finger contacts considered to be placed against each other on the opposite sides of the grasped object as is generally the case in a manufacturing environment is presented. The stiffness of the springs is exploited in order to achieve the stability in the soft-grasping which includes friction between the soft finger contact surfaces and the object, The paper also analyses stability of dynamic control through a soft interface between a manipulating finger and a manipulated object. It is shown in the paper that the system stability depends on the visco-elastic material properties of the soft interface. Method of root locus is used to analyze this phenomenon. The paper shows how the weight of the object coming downward is controlled by the friction between the fingers and the object during the application of contact forces by varying the damping and the stiffness in the soft finger. (author)

  3. Lifetime limitations of ohmic, contacting RF MEMS switches with Au, Pt and Ir contact materials due to accumulation of ‘friction polymer’ on the contacts

    International Nuclear Information System (INIS)

    Czaplewski, David A; Nordquist, Christopher D; Dyck, Christopher W; Patrizi, Gary A; Kraus, Garth M; Cowan, William D

    2012-01-01

    We present lifetime limitations and failure analysis of many packaged RF MEMS ohmic contacting switches with Au–Au, Au–Ir, and Au–Pt contact materials operating with 100 µN of contact force per contact in hermetically sealed glass wall packages. All metals were tested using the same switch design in a controlled environment to provide a comparison between the performance of the different materials and their corresponding failure mechanisms. The switch lifetimes of the different contact materials varied from several hundred cycles to 200 million cycles with different mechanisms causing failures for different contact materials. Switches with Au–Au contacts failed due to adhesion when thoroughly cleaned while switches with dissimilar metal contacts (Au–Ir and Au–Pt) operated without adhesion failures but failed due to carbon accumulation on the contacts even in a clean, packaged environment as a result of the catalytic behavior of the contact materials. Switch lifetimes correlated inversely with catalytic behavior of the contact metals. The data suggests the path to increase switch lifetime is to use favorable catalytic materials as contacts, design switches with higher contact forces to break through any residual contamination, and use cleaner, probably smaller, packages. (paper)

  4. Barrier height enhancement of metal/semiconductor contact by an enzyme biofilm interlayer

    Science.gov (United States)

    Ocak, Yusuf Selim; Gul Guven, Reyhan; Tombak, Ahmet; Kilicoglu, Tahsin; Guven, Kemal; Dogru, Mehmet

    2013-06-01

    A metal/interlayer/semiconductor (Al/enzyme/p-Si) MIS device was fabricated using α-amylase enzyme as a thin biofilm interlayer. It was observed that the device showed an excellent rectifying behavior and the barrier height value of 0.78 eV for Al/α-amylase/p-Si was meaningfully larger than the one of 0.58 eV for conventional Al/p-Si metal/semiconductor (MS) contact. Enhancement of the interfacial potential barrier of Al/p-Si MS diode was realized using enzyme interlayer by influencing the space charge region of Si semiconductor. The electrical properties of the structure were executed by the help of current-voltage and capacitance-voltage measurements. The photovoltaic properties of the structure were executed under a solar simulator with AM1.5 global filter between 40 and 100 mW/cm2 illumination conditions. It was also reported that the α-amylase enzyme produced from Bacillus licheniformis had a 3.65 eV band gap value obtained from optical method.

  5. Enzyme Immobilization: An Overview on Methods, Support Material, and Applications of Immobilized Enzymes.

    Science.gov (United States)

    Sirisha, V L; Jain, Ankita; Jain, Amita

    Immobilized enzymes can be used in a wide range of processes. In recent years, a variety of new approaches have emerged for the immobilization of enzymes that have greater efficiency and wider usage. During the course of the last two decades, this area has rapidly expanded into a multidisciplinary field. This current study is a comprehensive review of a variety of literature produced on the different enzymes that have been immobilized on various supporting materials. These immobilized enzymes have a wide range of applications. These include applications in the sugar, fish, and wine industries, where they are used for removing organic compounds from waste water. This study also reviews their use in sophisticated biosensors for metabolite control and in situ measurements of environmental pollutants. Immobilized enzymes also find significant application in drug metabolism, biodiesel and antibiotic production, bioremediation, and the food industry. The widespread usage of immobilized enzymes is largely due to the fact that they are cheaper, environment friendly, and much easier to use when compared to equivalent technologies. © 2016 Elsevier Inc. All rights reserved.

  6. Solutions of dissimilar material singularity and contact problems

    International Nuclear Information System (INIS)

    Yang, Y.

    2003-09-01

    Due to the mismatch of the material properties of joined components, after a homogeneous temperature change or under a mechanical loading, very high stresses occur near the intersection of the interface and the outer surface, or near the intersection of two interfaces. For most material combinations and joint geometries, there exists even a stress singularity. These high stresses may cause fracture of the joint. The investigation of the stress situation near the singular point, therefore, is of great interest. Especially, the relationship between the singular stress exponent, the material data and joint geometry is important for choosing a suitable material combination and joint geometry. In this work, the singular stress field is described analytically in case of the joint having a real and a complex eigenvalue. Solutions of different singularity problems are given, which are two dissimilar materials joint with free edges; dissimilar materials joint with edge tractions; joint with interface corner; joint with a given displacement at one edge; cracks in dissimilar materials joint; contact problem in dissimilar materials and logarithmic stress singularity. For an arbitrary joint geometry and material combination, the stress singular exponent, the angular function and the regular stress term can be calculated analytically. The stress intensity factors for a finite joint can be determined applying numerical methods, e.g. the finite element method (FEM). The method to determine more than one stress intensity factor is presented. The characteristics of the eigenvalues and the stress intensity factors are shown for different joint conditions. (orig.)

  7. Shear test on viscoelastic granular material using Contact Dynamics simulations

    Science.gov (United States)

    Quezada, Juan Carlos; Sagnol, Loba; Chazallon, Cyrille

    2017-06-01

    By means of 3D contact dynamic simulations, the behavior of a viscoelastic granular material under shear loading is investigated. A viscoelastic fluid phase surrounding the solid particles is simulated by a contact model acting between them. This contact law was implemented in the LMGC90 software, based on the Burgers model. This model is able to simulate also the effect of creep relaxation. To validate the proposed contact model, several direct shear tests were performed, experimentally and numerically using the Leutner device. The numerical samples were created using spheres with two particle size distribution, each one identified for two layers from a road structure. Our results show a reasonable agreement between experimental and numerical data regarding the strain-stress evolution curves and the stress levels measured at failure. The proposed model can be used to simulate the mechanical behavior of multi-layer road structure and to study the influence of traffic on road deformation, cracking and particles pull-out induced by traffic loading.

  8. A review of micro-contact physics, materials, and failure mechanisms in direct-contact RF MEMS switches

    International Nuclear Information System (INIS)

    Basu, A; Adams, G G; McGruer, N E

    2016-01-01

    Direct contact, ohmic MEMS switches for RF applications have several advantages over other conventional switching devices. Advantages include lower insertion loss, higher isolation, and better switching figure-of-merit (cut-off frequency). The most important aspect of a direct-contact RF MEMS switch is the metal microcontact which can dictate the lifetime and reliability of the switch. Therefore, an understanding of contact reliability is essential for developing robust MEMS switches. This paper discusses and reviews the most important work done over the past couple of decades toward understanding ohmic micro-contacts. We initially discuss the contact mechanics and multi-physics models for studying Hertzian and multi-asperity contacts. We follow this with a discussion on models and experiments for studying adhesion. We then discuss experimental setups and the development of contact test stations by various groups for accelerated testing of microcontacts, as well as for analysis of contact reliability issues. Subsequently, we analyze a number of material transfer mechanisms in microcontacts under hot and cold switching conditions. We finally review the material properties that can help determine the selection of contact materials. A trade-off between contact resistance and high reliability is almost always necessary during selection of contact material; this paper discusses how the choice of materials can help address such trade-offs. (paper)

  9. Fuel cell electrode interconnect contact material encapsulation and method

    Science.gov (United States)

    Derose, Anthony J.; Haltiner, Jr., Karl J.; Gudyka, Russell A.; Bonadies, Joseph V.; Silvis, Thomas W.

    2016-05-31

    A fuel cell stack includes a plurality of fuel cell cassettes each including a fuel cell with an anode and a cathode. Each fuel cell cassette also includes an electrode interconnect adjacent to the anode or the cathode for providing electrical communication between an adjacent fuel cell cassette and the anode or the cathode. The interconnect includes a plurality of electrode interconnect protrusions defining a flow passage along the anode or the cathode for communicating oxidant or fuel to the anode or the cathode. An electrically conductive material is disposed between at least one of the electrode interconnect protrusions and the anode or the cathode in order to provide a stable electrical contact between the electrode interconnect and the anode or cathode. An encapsulating arrangement segregates the electrically conductive material from the flow passage thereby, preventing volatilization of the electrically conductive material in use of the fuel cell stack.

  10. Bio-functionalization of conductive textile materials with redox enzymes

    Science.gov (United States)

    Kahoush, M.; Behary, N.; Cayla, A.; Nierstrasz, V.

    2017-10-01

    In recent years, immobilization of oxidoreductase enzymes on electrically conductive materials has played an important role in the development of sustainable bio-technologies. Immobilization process allows the re-use of these bio-catalysts in their final applications. In this study, different methods of immobilizing redox enzymes on conductive textile materials were used to produce bio-functionalized electrodes. These electrodes can be used for bio-processes and bio-sensing in eco-designed applications in domains such as medicine and pollution control. However, the main challenge facing the stability and durability of these electrodes is the maintenance of the enzymatic activity after the immobilization. Hence, preventing the enzyme’s denaturation and leaching is a critical factor for the success of the immobilization processes.

  11. NANOCOMPOSITE POWDERS FOR NEW CONTACT MATERIALS BASED ONCOPPER AND ALUMINA

    Directory of Open Access Journals (Sweden)

    Marija Korać

    2008-11-01

    Full Text Available This paper is a contribution to characterization of Cu-Al2O3 powders with nanostructure designed for the production of dispersion strengthened contact materials. New materials with predetermined properties can be successfully synthesized by utilizing the principles of hydrometallurgy and powder metallurgy. The results show a development of a new procedure for the synthesis. The applied characterization methods were differential thermal and thermogravimetric analysis (DTA-TGA, X-ray diffraction (XRD, scanning electron microscopy (SEM, Transmission Electron Microscopy (TEM: Focused Ion Beam (FIB and Analytical Electron Microscopy (AEM. Nanostructure characteristics, particle size in range 20-50 nm, and uniform distribution of dispersoide in copper matrix were validated.

  12. Behavior of bone cells in contact with magnesium implant material.

    Science.gov (United States)

    Burmester, Anna; Willumeit-Römer, Regine; Feyerabend, Frank

    2017-01-01

    Magnesium-based implants exhibit several advantages, such as biodegradability and possible osteoinductive properties. Whether the degradation may induce cell type-specific changes in metabolism still remains unclear. To examine the osteoinductivity mechanisms, the reaction of bone-derived cells (MG63, U2OS, SaoS2, and primary human osteoblasts (OB)) to magnesium (Mg) was determined. Mg-based extracts were used to mimic more realistic Mg degradation conditions. Moreover, the influence of cells having direct contact with the degrading Mg metal was investigated. In exposure to extracts and in direct contact, the cells decreased pH and osmolality due to metabolic activity. Proliferating cells showed no significant reaction to extracts, whereas differentiating cells were negatively influenced. In contrast to extract exposure, where cell size increased, in direct contact to magnesium, cell size was stable or even decreased. The amount of focal adhesions decreased over time on all materials. Genes involved in bone formation were significantly upregulated, especially for primary human osteoblasts. Some osteoinductive indicators were observed for OB: (i) an increased cell count after extract addition indicated a higher proliferation potential; (ii) increased cell sizes after extract supplementation in combination with augmented adhesion behavior of these cells suggest an early switch to differentiation; and (iii) bone-inducing gene expression patterns were determined for all analyzed conditions. The results from the cell lines were inhomogeneous and showed no specific stimulus of Mg. The comparison of the different cell types showed that primary cells of the investigated tissue should be used as an in vitro model if Mg is analyzed. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 165-179, 2017. © 2015 Wiley Periodicals, Inc.

  13. Non-Contact Measurements of Creep Properties of Refractory Materials

    Science.gov (United States)

    Lee, Jonghyun; Bradshaw, Richard C.; Hyers, Robert W.; Rogers, Jan R.; Rathz, Thomas J.; Wall, James J.; Choo, Hahn; Liaw, Peter

    2006-01-01

    State-of-the-art technologies for hypersonic aircraft, nuclear electric/thermal propulsion for spacecraft, and more efficient jet engines are driving ever more demanding needs for high-temperature (>2000 C) materials. At such high temperatures, creep rises as one of the most important design factors to be considered. Since conventional measurement techniques for creep resistance are limited to about 17OO0C, a new technique is in demand for higher temperatures. This paper presents a non-contact method using electrostatic levitation (ESL) which is applicable to both metallic and non-metallic materials. The samples were rotated quickly enough to cause creep deformation by centrifugal acceleration. The deformation of the samples was captured with a high speed camera and then the images were analyzed to estimate creep resistance. Finite element analyses were performed and compared to the experiments to verify the new method. Results are presented for niobium and tungsten, representative refractory materials at 2300 C and 2700 C respectively.

  14. EFSA Panel on Food Contact Material, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 201Rev1: 2-Alkylated, aliphatic, acyclic alpha,beta-unsaturated aldehydes and precursors, with or without additional double-bonds, from chemical subgroup 1.1.2 of FGE.19

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    . The Panel therefore concluded that further data are required in order to clarify the genotoxic potential of this subgroup. The Panel considers the Comet assay with [FL-no: 05.095] as test material and performed on liver, blood and first site of contact, as a preferred option to further investigate.......177 and 09.931], for which it was concluded in the previous version of this FGE that the available data were insufficient to evaluate their genotoxicity. Secondly, the Panel considers that the mutagenicity hazard could not be cleared by the endpoints evaluated in the in vivo micronucleus assay submitted...

  15. Enzyme

    Science.gov (United States)

    Enzymes are complex proteins that cause a specific chemical change in all parts of the body. For ... use them. Blood clotting is another example of enzymes at work. Enzymes are needed for all body ...

  16. Enzyme Immobilization on Inorganic Surfaces for Membrane Reactor Applications: Mass Transfer Challenges, Enzyme Leakage and Reuse of Materials

    DEFF Research Database (Denmark)

    Sigurdardóttir, Sigyn Björk; Lehmann, Jonas; Ovtar, Simona

    2018-01-01

    Enzyme immobilization is an established method for the enhancement of enzyme stability and reusability, two factors that are of great importance for industrial biocatalytic applications. Immobilization can be achieved by different methods and on a variety of carrier materials, both organic and in...

  17. Non-contact tensile viscoelastic characterization of microscale biological materials

    Science.gov (United States)

    Li, Yuhui; Hong, Yuan; Xu, Guang-Kui; Liu, Shaobao; Shi, Qiang; Tang, Deding; Yang, Hui; Genin, Guy M.; Lu, Tian Jian; Xu, Feng

    2018-06-01

    Many structures and materials in nature and physiology have important "meso-scale" structures at the micron length-scale whose tensile responses have proven difficult to characterize mechanically. Although techniques such as atomic force microscopy and micro- and nano-identation are mature for compression and indentation testing at the nano-scale, and standard uniaxial and shear rheometry techniques exist for the macroscale, few techniques are applicable for tensile-testing at the micrometre-scale, leaving a gap in our understanding of hierarchical biomaterials. Here, we present a novel magnetic mechanical testing (MMT) system that enables viscoelastic tensile testing at this critical length scale. The MMT system applies non-contact loading, avoiding gripping and surface interaction effects. We demonstrate application of the MMT system to the first analyses of the pure tensile responses of several native and engineered tissue systems at the mesoscale, showing the broad potential of the system for exploring micro- and meso-scale analysis of structured and hierarchical biological systems.

  18. Difficulties in using Material Safety Data Sheets to analyse occupational exposures to contact allergens

    DEFF Research Database (Denmark)

    Friis, Ulrik F; Menné, Torkil; Flyvholm, Mari-Ann

    2015-01-01

    BACKGROUND: Information on the occurrence of contact allergens and irritants is crucial for the diagnosis of occupational contact dermatitis. Material Safety Data Sheets (MSDS) are important sources of information concerning exposures in the workplace. OBJECTIVE: From a medical viewpoint...

  19. Multi-Material Front Contact for 19% Thin Film Solar Cells

    NARCIS (Netherlands)

    Deelen, J. van; Tezsevin, Y.; Barink, M.

    2016-01-01

    The trade-off between transmittance and conductivity of the front contact material poses abottleneck for thin film solar panels. Normally, the front contact material is a metal oxide and the optimal cell configuration and panel efficiency were determined for various band gap materials, representing

  20. Speci﬿c contact resistance of phase change materials to metal electrode

    NARCIS (Netherlands)

    Roy, Deepu; in 't Zandt, Micha A.A.; Wolters, Robertus A.M.

    2010-01-01

    For phase change random access memory (PCRAM) cells, it is important to know the contact resistance of phase change materials (PCMs) to metal electrodes at the contacts. In this letter, we report the systematic determination of the speci﬿c contact resistance (Ͽc ) of doped Sb2Te and Ge2Sb2Te5 to TiW

  1. Contact mechanics and friction for transversely isotropic viscoelastic materials

    NARCIS (Netherlands)

    Mokhtari, Milad; Schipper, Dirk J.; Vleugels, N.; Noordermeer, Jacobus W.M.; Yoshimoto, S.; Hashimoto, H.

    2015-01-01

    Transversely isotropic materials are an unique group of materials whose properties are the same along two of the principal axes of a Cartesian coordinate system. Various natural and artificial materials behave effectively as transversely isotropic elastic solids. Several materials can be classified

  2. Contact Resistance of Ceramic Interfaces Between Materials Used for Solid Oxide Fuel Cell Applications

    DEFF Research Database (Denmark)

    Koch, Søren

    The contact resistance can be divided into two main contributions. The small area of contact between ceramic components results in resistance due to current constriction. Resistive phases or potential barriers at the interface result in an interface contribution to the contact resistance, which may....... The influence of the mechanical load on the contact resistance was ascribed to an area effect. The contact resistance of the investigated materials was dominated by current constric-tion at high temperatures. The measured contact resistance was comparable to the resis-tance calculated on basis of the contact...... areas found by optical and electron microscopy. At low temperatures, the interface contribution to the contact resistance was dominating. The cobaltite interface could be described by one potential barrier at the contact interface, whereas the manganite interfaces required several consecutive potential...

  3. Contact resistance of ceramic interfaces between materials used for solid oxide fuel cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Koch, S.

    2002-01-01

    The contact resistance can be divided into two main contributions. The small area of contact between ceramic components results in resistance due to current constriction. Resistive phases or potential barriers at the interface result in an interface contribution to the contact resistance, which may be smaller or larger than the constriction resistance. The contact resistance between pairs of three different materials were analysed (strontium doped lanthanum manganite, yttria stabilised zirconia and strontium and nickel doped lanthanum cobaltite), and the effects of temperature, atmosphere, polarisation and mechanical load on the contact resistance were investigated. The investigations revealed that the mechanical load of a ceramic contact has a high influence on the contact resistance, and generally power law dependence between the contact resistance and the mechanical load was found. The influence of the mechanical load on the contact resistance was ascribed to an area effect. The contact resistance of the investigated materials was dominated by current constriction at high temperatures. The measured contact resistance was comparable to the resistance calculated on basis of the contact areas found by optical and electron microscopy. At low temperatures, the interface contribution to the contact resistance was dominating. The cobaltite interface could be described by one potential barrier at the contact interface, whereas the manganite interfaces required several consecutive potential barriers to model the observed behaviour. The current-voltage behaviour of the YSZ contact interfaces was only weakly non-linear, and could be described by 22{+-}1 barriers in series. Contact interfaces with sinterable contact layers were also investigated, and the measured contact resistance for these interfaces were more than 10 times less than for the other interfaces. (au)

  4. Behaviour of contact layer material between cermet fuel element core and can

    International Nuclear Information System (INIS)

    Gavrilin, S.S.; Permyakov, L.N.; Simakov, G.A.; Chernikov, A.S.

    1996-01-01

    The structural state of the contact layer between the shell of the Zr1Nb alloy and cermet fuel element core containing up to 70% of uranium dioxides is experimental studied. The silumin alloy was used as contact material. The results of studies on interaction zones, formed on the Zr1Nb - silumin boundary after fuel elements manufacture and also under temperature conditions, modeling the maximum design and hypothetical accidents accompanied by the contact material melting, are presented [ru

  5. Analysis of the material's expenditure of electric contacts by means of the isotopic method

    International Nuclear Information System (INIS)

    Farkash, K.

    1979-01-01

    To investigate lifetime of the weak-current and heavy-current contacts different radioisotopic methods have been developed. Advantages of the radioisotopic methods as compared with other methods of testing consists of the fact that due to their sensitivity they permit to determine low expense of material; permit to determine quantitatively expense of each element separately from the elements, composing the contacts alloy; by means of these methods it is possible to evaluate quantitatively topological distribution of the matter separated from the contacts into the environment; it is possible to determine morphological characteristics of the matter separated from the contact. During investigation of the lifetime of contacts there were determined: value of the expense of the material of contacts; composition of the expense of the material of contacts; composition of the matter separated from the contact; distribution of the separated matter depending on the electrical parameters and number of the closings of contact in the case of different compositions of contacts and in different conditions. Strength of the contacts' alloys related to the electrical load was investigated at the special stand [ru

  6. Surface modification of food contact materials for processing and packaging applications

    Science.gov (United States)

    Barish, Jeffrey A.

    This body of work investigates various techniques for the surface modification of food contact materials for use in food packaging and processing applications. Nanoscale changes to the surface of polymeric food packaging materials enables changes in adhesion, wettability, printability, chemical functionality, and bioactivity, while maintaining desirable bulk properties. Polymer surface modification is used in applications such as antimicrobial or non-fouling materials, biosensors, and active packaging. Non-migratory active packagings, in which bioactive components are tethered to the package, offer the potential to reduce the need for additives in food products while maintaining safety and quality. A challenge in developing non-migratory active packaging materials is the loss of biomolecular activity that can occur when biomolecules are immobilized. Polyethylene glycol (PEG), a biocompatible polymer, is grafted from the surface of ozone treated low-density polyethylene (LDPE) resulting in a surface functionalized polyethylene to which a range of amine-terminated bioactive molecules can be immobilized. The grafting of PEG onto the surface of polymer packaging films is accomplished by free radical graft polymerization, and to covalently link an amine-terminated molecule to the PEG tether, demonstrating that amine-terminated bioactive compounds (such as peptides, enzymes, and some antimicrobials) can be immobilized onto PEG-grafted LDPE in the development of non-migratory active packaging. Fouling on food contact surfaces during food processing has a significant impact on operating efficiency and can promote biofilm development. Processing raw milk on plate heat exchangers results in significant fouling of proteins as well as minerals, and is exacerbated by the wall heating effect. An electroless nickel coating is co-deposited with polytetrafluoroethylene onto stainless steel to test its ability to resist fouling on a pilot plant scale plate heat exchanger. Further

  7. Hyaluronan Immobilized Polyurethane as a Blood Contacting Material

    Directory of Open Access Journals (Sweden)

    Feirong Gong

    2010-01-01

    Full Text Available Hyaluronan (hyaluronic acid, HA was immobilized onto the surface of amino-functionalized polyurethane films with the goal of obtaining a novel kind of biomaterial which had the potential in blood-contacting applications. The amino-functionalized polyurethane was prepared by synthesized acidic polyurethane whose pendant carboxyl groups were treated with an excess amount of 1,3-diaminopropane in the presence of N,N-carbonyldiimidazole (CDI. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR, Raman spectroscopy (RS, scanning electron microscopy (SEM, and water contact angle measurement were used to confirm the surface changes at each step of treatment, both in morphologies and chemical compositions. APTT and PT results showed that HA immobilization could prolong the blood coagulation time, thus HA-immobilized polyurethane (PU-HA exhibited improved blood compatibility. Cytotoxicity analysis showed that the PU-HA films synthesized in this study were cytocompatible and could support human vein endothelial cells (HUVECs adhesion and proliferation.

  8. Combining adhesive contact mechanics with a viscoelastic material model to probe local material properties by AFM.

    Science.gov (United States)

    Ganser, Christian; Czibula, Caterina; Tscharnuter, Daniel; Schöberl, Thomas; Teichert, Christian; Hirn, Ulrich

    2017-12-20

    Viscoelastic properties are often measured using probe based techniques such as nanoindentation (NI) and atomic force microscopy (AFM). Rarely, however, are these methods verified. In this article, we present a method that combines contact mechanics with a viscoelastic model (VEM) composed of springs and dashpots. We further show how to use this model to determine viscoelastic properties from creep curves recorded by a probe based technique. We focus on using the standard linear solid model and the generalized Maxwell model of order 2. The method operates in the range of 0.01 Hz to 1 Hz. Our approach is suitable for rough surfaces by providing a defined contact area using plastic pre-deformation of the material. The very same procedure is used to evaluate AFM based measurements as well as NI measurements performed on polymer samples made from poly(methyl methacrylate) and polycarbonate. The results of these measurements are then compared to those obtained by tensile creep tests also performed on the same samples. It is found that the tensile test results differ considerably from the results obtained by AFM and NI methods. The similarity between the AFM results and NI results suggests that the proposed method is capable of yielding results comparable to NI but with the advantage of the imaging possibilities of AFM. Furthermore, all three methods allowed a clear distinction between PC and PMMA by means of their respective viscoelastic properties.

  9. Effects of pressure and temperature on thermal contact resistance between different materials

    Directory of Open Access Journals (Sweden)

    Zhao Zhe

    2015-01-01

    Full Text Available To explore whether pressure and temperature can affect thermal contact resistance, we have proposed a new experimental approach for measurement of the thermal contact resistance. Taking the thermal contact resistance between phenolic resin and carbon-carbon composites, cuprum, and aluminum as the examples, the influence of the thermal contact resistance between specimens under pressure is tested by experiment. Two groups of experiments are performed and then an analysis on influencing factors of the thermal contact resistance is presented in this paper. The experimental results reveal that the thermal contact resistance depends not only on the thermal conductivity coefficient of materials, but on the interfacial temperature and pressure. Furthermore, the thermal contact resistance between cuprum and aluminum is more sensitive to pressure and temperature than that between phenolic resin and carbon-carbon composites.

  10. Thermal contact resistance in carbon nanotube enhanced heat storage materials

    NARCIS (Netherlands)

    Zhang, H.; Nedea, S.V.; Rindt, C.C.M.; Smeulders, D.M.J.

    2015-01-01

    Solid-liquid phase change is one of the most favorable means of compact and economical heat storage in the built environment. In such storage systems, the vast available solar heat is stored as latent heat in the storage materials. Recent studies suggest using sugar alcohols as seasonal heat storage

  11. Chemical identification of contaminants in paper and board food contact materials

    DEFF Research Database (Denmark)

    Bengtström, Linda

    Paper and board are used for a variety of food contact materials, such as baking paper, microwave popcorn bags and packaging for cereals as well as fast foods. Despite this extensive use, there are currently large data gaps about the chemical composition of different paper and board food contact...

  12. Novel Contact Materials for Improved Performance CdTe Solar Cells Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Rockett, Angus [Colorado School of Mines, Golden, CO (United States); Marsillac, Sylvain [Old Dominion Univ., Norfolk, VA (United States); Collins, Robert [Univesity of Toledo

    2018-04-15

    This program has explored a number of novel materials for contacts to CdTe solar cells in order to reduce the back contact Schottky barrier to zero and produce an ohmic contact. The project tested a wide range of potential contact materials including TiN, ZrN, CuInSe2:N, a-Si:H and alloys with C, and FeS2. Improved contacts were achieved with FeS2. As part of understanding the operation of the devices and controlling the deposition processes, a number of other important results were obtained. In the process of this project and following its conclusion it led to research that resulted in seven journal articles, nine conference publications, 13 talks presented at conferences, and training of eight graduate students. The seven journal articles were published in 2015, 2016, and 2017 and have been cited, as of March 2018, 52 times (one cited 19 times and two cited 11 times). We demonstrated high levels of doping of CIS with N but electrical activity of the resulting N was not high and the results were difficult to reproduce. Furthermore, even with high doping the contacts were not good. Annealing did not improve the contacts. A-Si:H was found to produce acceptable but unstable contacts, degrading even over a day or two, apparently due to H incorporation into the CdTe. Alloying with C did not improve the contacts or stability. The transition metal nitrides produced Schottky type contacts for all materials tested. While these contacts were found to be unsatisfactory, we investigated FeS2 and found this material to be effective and comparable to the best contacts currently available. The contacts were found to be chemically stable under heat treatment and preferable to Cu doped contacts. Thus, we demonstrated an improved contact material in the course of this project. In addition, we developed new ways of controlling the deposition of CdTe and other materials, demonstrated the nature of defects in CdTe, and studied the distribution of conductivity and carrier type in Cd

  13. Survey of the occurrence of 1,6-hexanediol diglycidyl ether in food contact materials

    DEFF Research Database (Denmark)

    producers and importers. The substance is not allowed for use in plastic materials for food contact. One Danish company reported a possible use of HDDGE in coating of drinking tanks and pipelines. This is the only use of HDDGE confirmed in relation to food contact materials in Denmark. The project...... is following up on a previous survey under the Danish EPA’s LOUS-review (Environmental Project no. 1472)....

  14. Contact problem for a composite material with nacre inspired microstructure

    Science.gov (United States)

    Berinskii, Igor; Ryvkin, Michael; Aboudi, Jacob

    2017-12-01

    Bi-material composites with nacre inspired brick and mortar microstructures, characterized by stiff elements of one phase with high aspect ratio separated by thin layers of the second one, are considered. Such microstructure is proved to provide an efficient solution for the problem of a crack arrest. However, contrary to the case of a homogeneous material, an external pressure, applied to a part of the composite boundary, can cause significant tensile stresses which increase the danger of crack nucleation. Investigation of the influence of microstructure parameters on the magnitude of tensile stresses is performed by means of the classical Flamant-like problem of an orthotropic half-plane subjected to a normal external distributed loading. Adequate analysis of this problem represents a serious computational task due to the geometry of the considered layout and the high contrast between the composite constituents. This difficulty is presently circumvented by deriving a micro-to-macro analysis in the framework of which an analytical solution of the auxiliary elasticity problem, followed by the discrete Fourier transform and the higher-order theory are employed. As a result, full scale continuum modeling of both composite constituents without employing any simplifying assumptions is presented. In the framework of the present proposed modeling, the influence of stiff elements aspect ratio on the overall stress distribution is demonstrated.

  15. Evaluating use stage exposure to food contact materials in a LCA framework

    DEFF Research Database (Denmark)

    Ernstoff, Alexi; Jolliet, Olivier; Fantke, Peter

    2015-01-01

    We present novel methods to incorporate exposure to chemicals within food contact materials (FCM) (e.g. packaging) into life cycle impact assessment (LCIA). Chemical migration into food is modeled as a function of contact temperature, time, and various chemical, FCM, and food properties. In order...... in a way compatible with intake fraction, iF, a metric traditionally used in LCIA. The model predicts PiF increases with temperature and for compounds with lower octanol-water partition coefficients within more permeable materials which are in contact with foods with high ethanol equivalencies (fatty foods)....

  16. Light-addressable amperometric electrodes for enzyme sensors based on direct quantum dot-electrode contacts

    Science.gov (United States)

    Riedel, M.; Göbel, G.; Parak, W. J.; Lisdat, F.

    2014-03-01

    Quantum dots allow the generation of charge carriers upon illumination. When these particles are attached to an electrode a photocurrent can be generated. This allows their use as a light-switchable layer on the surface. The QDs can not only exchange electronics with the electrode, but can also interact with donor or acceptor compounds in solution providing access to the construction of signal chains starting from an analytic molecule. The magnitude and the direction of the photocurrent depend on several factors such as electrode polarization, solution pH and composition. These defined dependencies have been evaluated with respect to the combination of QD-electrodes with enzyme reactions for sensorial purpose. CdSe/ZnS-QD-modified electrodes can be used to follow enzymatic reactions in solution based on the oxygen sensitivity. In order to develop a photoelectrochemical biosensor, e.g. glucose oxidase is immobilized on the CdSe/ZnS-electrode. One immobilization strategy applies the layer-by-layer-technique of GOD and a polyelectrolyte. Photocurrent measurements of such a sensor show a clear concentration dependent behavior. The principle of combing QD oxidase. The sensitivity of quantum dot electrodes can be influenced by additional nanoparticles, but also by multiple layers of the QDs. In another direction of research it can be influenced by additional nanoparticles, but also by multiple layers of the QDs. In another direction of research it can be demonstrated that direct electron transfer from excited quantum dots can be achieved with the redox protein cytochrome c. This allows the detection of the protein, but also interaction partners such as a enzymes or superoxide.

  17. The mechanisms and models of interaction between electrical arc and contact materials

    International Nuclear Information System (INIS)

    Kharin, S.N.

    1999-01-01

    Mechanisms of arc erosion in electrical contacts are different and depends on the conditions of contact separation. The first one, which occurs at low current with relatively slow rate of heat transfer, involves the evaporation of material from the contact surface. The second mechanism can be characterized by the formation of droplets of molten metal caused by high currents and vapor or magnetic pressure on a molten metal pool. However, in certain cases it is impossible to explain the formation of molten metal droplets in terms of pressure only. Therefore a new hypothesis regarding thermo-capillary mechanism of ejection of liquid metal is discussed. This hypothesis is based on the Marangoni effect which is important when the temperature gradient along the liquid contact zone and the temperature dependence of surface tension become significant (tungsten, zirconium, molybdenum etc.). The fourth erosion mechanism is associated with the ejection of solid particles of contact material with distinct crystalline structure during high current pulses of a short duration. It occurs when thermo-elastic processes overcome the mechanical strength. A mathematical model describing each of the four mechanisms of erosion is presented. Temperature fields and erosion characteristics are determined as a function of the commutation regime and the properties of contact materials. The experimental data are discussed in terms of theoretical approach with respect to the solid phase and droplet formation. Dynamics of each type of arc erosion is described, and recommendations for optimal selection of contact material with minimum erosion are given. (author)

  18. Pancreatic Enzymes

    Science.gov (United States)

    ... Contact Us DONATE NOW GENERAL DONATION PURPLESTRIDE Pancreatic enzymes Home Facing Pancreatic Cancer Living with Pancreatic Cancer ... and see a registered dietitian. What are pancreatic enzymes? Pancreatic enzymes help break down fats, proteins and ...

  19. Material properties that predict preservative uptake for silicone hydrogel contact lenses.

    Science.gov (United States)

    Green, J Angelo; Phillips, K Scott; Hitchins, Victoria M; Lucas, Anne D; Shoff, Megan E; Hutter, Joseph C; Rorer, Eva M; Eydelman, Malvina B

    2012-11-01

    To assess material properties that affect preservative uptake by silicone hydrogel lenses. We evaluated the water content (using differential scanning calorimetry), effective pore size (using probe penetration), and preservative uptake (using high-performance liquid chromatography with spectrophotometric detection) of silicone and conventional hydrogel soft contact lenses. Lenses grouped similarly based on freezable water content as they did based on total water content. Evaluation of the effective pore size highlighted potential differences between the surface-treated and non-surface-treated materials. The water content of the lens materials and ionic charge are associated with the degree of preservative uptake. The current grouping system for testing contact lens-solution interactions separates all silicone hydrogels from conventional hydrogel contact lenses. However, not all silicone hydrogel lenses interact similarly with the same contact lens solution. Based upon the results of our research, we propose that the same material characteristics used to group conventional hydrogel lenses, water content and ionic charge, can also be used to predict uptake of hydrophilic preservatives for silicone hydrogel lenses. In addition, the hydrophobicity of silicone hydrogel contact lenses, although not investigated here, is a unique contact lens material property that should be evaluated for the uptake of relatively hydrophobic preservatives and tear components.

  20. Simultaneous Contact Sensing and Characterizing of Mechanical and Dynamic Heat Transfer Properties of Porous Polymeric Materials

    Directory of Open Access Journals (Sweden)

    Bao-guo Yao

    2017-10-01

    Full Text Available Porous polymeric materials, such as textile fabrics, are elastic and widely used in our daily life for garment and household products. The mechanical and dynamic heat transfer properties of porous polymeric materials, which describe the sensations during the contact process between porous polymeric materials and parts of the human body, such as the hand, primarily influence comfort sensations and aesthetic qualities of clothing. A multi-sensory measurement system and a new method were proposed to simultaneously sense the contact and characterize the mechanical and dynamic heat transfer properties of porous polymeric materials, such as textile fabrics in one instrument, with consideration of the interactions between different aspects of contact feels. The multi-sensory measurement system was developed for simulating the dynamic contact and psychological judgment processes during human hand contact with porous polymeric materials, and measuring the surface smoothness, compression resilience, bending and twisting, and dynamic heat transfer signals simultaneously. The contact sensing principle and the evaluation methods were presented. Twelve typical sample materials with different structural parameters were measured. The results of the experiments and the interpretation of the test results were described. An analysis of the variance and a capacity study were investigated to determine the significance of differences among the test materials and to assess the gage repeatability and reproducibility. A correlation analysis was conducted by comparing the test results of this measurement system with the results of Kawabata Evaluation System (KES in separate instruments. This multi-sensory measurement system provides a new method for simultaneous contact sensing and characterizing of mechanical and dynamic heat transfer properties of porous polymeric materials.

  1. Experimental Study on the Interaction Between Contacting Barrier Materials for Containment of Radioactive Wastes

    Science.gov (United States)

    Huang, W. H.; Chang, H. C.

    2017-12-01

    The disposal of low- and intermediate-level radioactive wastes requires use of multi-barriers for isolation of the wastes from the biosphere. Typically, the engineered barriers are composed of a concrete vault, buffer and backfill materials. Zhishin clay and Black Hill bentonite were used as raw clay material in making buffer and backfill materials in this study. These clays were compacted to make buffer material, or mixed with Taitung area argillite to produce backfill material for potential application as barriers for the disposal of low- and intermediate-level radioactive wastes. The interaction between concrete barrier and the buffer/backfill material is simulated by an accelerated migration test to investigate the effect of contacting concrete on the expected functions of buffer/backfill material. The results show buffer material close to the contact with concrete exhibits significant change in the ratio of calcium/sodium exchange capacity, due to the move of calcium ions released from the concrete. The shorter the distance from the contacting interface, the ratio of the calcium/sodium concentration in buffer/backfill materials increases. The longer the distance from the interface, the effect of the contact on alteration in clays become less significant. Also, some decreases in swelling capacity in the buffer/backfill material near the concrete-backfill interface are noted. Finally, a comparison is made between Zhisin clay and Balck Hill bentonite on the interaction between concrete and the two clays. Black Hill bentonite was found to be influenced more by the interaction, because of the higher content of montmorillonite. On the other hand, being a mixture of clay and sand, backfill material is less affected by the decalsification of concrete at the contact than buffer material.

  2. Evolution of real contact area under shear and the value of static friction of soft materials.

    Science.gov (United States)

    Sahli, R; Pallares, G; Ducottet, C; Ben Ali, I E; Al Akhrass, S; Guibert, M; Scheibert, J

    2018-01-16

    The frictional properties of a rough contact interface are controlled by its area of real contact, the dynamical variations of which underlie our modern understanding of the ubiquitous rate-and-state friction law. In particular, the real contact area is proportional to the normal load, slowly increases at rest through aging, and drops at slip inception. Here, through direct measurements on various contacts involving elastomers or human fingertips, we show that the real contact area also decreases under shear, with reductions as large as 30[Formula: see text], starting well before macroscopic sliding. All data are captured by a single reduction law enabling excellent predictions of the static friction force. In elastomers, the area-reduction rate of individual contacts obeys a scaling law valid from micrometer-sized junctions in rough contacts to millimeter-sized smooth sphere/plane contacts. For the class of soft materials used here, our results should motivate first-order improvements of current contact mechanics models and prompt reinterpretation of the rate-and-state parameters.

  3. Fungal enzyme production in seeds of transgenic canola plants for conversion of cellulosic materials to ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, K.J.; Beauchemin, K.A. [Agriculture and Agri-Food Canada, Lethbridge, AB (Canada); Moloney, M.M. [Calgary Univ., AB (Canada). Dept. of Biological Sciences

    1997-07-01

    The fuel alcohol industry makes use of industrial enzymes to effectively degrade fibrous plant cell walls. Carbohydrates in cellulosic materials are in the form of complex sugars that can be hydrolyzed to simple sugars by fungal fibrolytic enzymes such as cellulases and xylanases. This study was conducted to find a cost effective way to produce fibrolytic enzymes using gene fusion technology in which a xylanase gene and a cellulase gene from two fungal species are introduced into canola to be a carrier for the production of these enzymes. The two genes had been analyzed for maximal enzymatic activity to minimize side effects. Results of the study demonstrated the stability and potential of transgenic oil-bodies as an immobilized enzyme matrix, and showed that it is possible to express fibrolytic enzymes in canola.

  4. Multi-Material Front Contact for 19% Thin Film Solar Cells

    Directory of Open Access Journals (Sweden)

    Joop van Deelen

    2016-02-01

    Full Text Available The trade-off between transmittance and conductivity of the front contact material poses a bottleneck for thin film solar panels. Normally, the front contact material is a metal oxide and the optimal cell configuration and panel efficiency were determined for various band gap materials, representing Cu(In,GaSe2 (CIGS, CdTe and high band gap perovskites. Supplementing the metal oxide with a metallic copper grid improves the performance of the front contact and aims to increase the efficiency. Various front contact designs with and without a metallic finger grid were calculated with a variation of the transparent conductive oxide (TCO sheet resistance, scribing area, cell length, and finger dimensions. In addition, the contact resistance and illumination power were also assessed and the optimal thin film solar panel design was determined. Adding a metallic finger grid on a TCO gives a higher solar cell efficiency and this also enables longer cell lengths. However, contact resistance between the metal and the TCO material can reduce the efficiency benefit somewhat.

  5. Improvement and evaluation of thermal, electrical, sealing and mechanical contacts, and their interface materials

    Science.gov (United States)

    Luo, Xiangcheng

    Material contacts, including thermal, electrical, seating (fluid sealing and electromagnetic sealing) and mechanical (pressure) contacts, together with their interface materials, were, evaluated, and in some cases, improved beyond the state of the art. The evaluation involved the use of thermal, electrical and mechanical methods. For thermal contacts, this work evaluated and improved the heat transfer efficiency between two contacting components by developing various thermal interface pastes. Sodium silicate based thermal pastes (with boron nitride particles as the thermally conductive filler) as well as polyethylene glycol (PEG) based thermal pastes were developed and evaluated. The optimum volume fractions of BN in sodium silicate based pastes and PEG based pastes were 16% and 18% respectively. The contribution of Li+ ions to the thermal contact conductance in the PEG-based paste was confirmed. For electrical contacts, the relationship between the mechanical reliability and electrical reliability of solder/copper and silver-epoxy/copper joints was addressed. Mechanical pull-out testing was conducted on solder/copper and silver-epoxy/copper joints, while the contact electrical resistivity was measured. Cleansing of the copper surface was more effective for the reliability of silver-epoxy/copper joint than that of solder/copper joint. For sealing contacts, this work evaluated flexible graphite as an electromagnetic shielding gasket material. Flexible graphite was found to be at least comparable to conductive filled silicone (the state of the art) in terms of the shielding effectiveness. The conformability of flexible graphite with its mating metal surface under repeated compression was characterized by monitoring the contact electrical resistance, as the conformability is important to both electromagnetic scaling and fluid waling using flexible graphite. For mechanical contacts, this work focused on the correlation of the interface structure (such as elastic

  6. Influence of hole transport material/metal contact interface on perovskite solar cells

    Science.gov (United States)

    Lei, Lei; Zhang, Shude; Yang, Songwang; Li, Xiaomin; Yu, Yu; Wei, Qingzhu; Ni, Zhichun; Li, Ming

    2018-06-01

    Interfaces have a significant impact on the performance of perovskite solar cells. This work investigated the influence of hole transport material/metal contact interface on photovoltaic behaviours of perovskite solar devices. Different hole material/metal contact interfaces were obtained by depositing the metal under different conditions. High incident kinetic energy metal particles were proved to penetrate and embed into the hole transport material. These isolated metal particles in hole transport materials capture holes and increase the apparent carrier transport resistance of the hole transport layer. Sample temperature was found to be of great significance in metal deposition. Since metal vapour has a high temperature, the deposition process accumulated a large amount of heat. The heat evaporated the additives in the hole transport layer and decreased the hole conductivity. On the other hand, high temperature may cause iodization of the metal contact.

  7. Contact materials for thermostable resistors on the base of Ni-Re alloy

    International Nuclear Information System (INIS)

    Yusipov, H.Yu.; Glasman, L.I.; Arskaya, E.P.; Lazarev, Eh.M.; Korotkov, N.A.

    1979-01-01

    Given are the electron diffraction analysis results and the operational characteristics of the contact materials, used in the heat-resistant thin-filmed resistors (TFR), made on the basis of the Ni-Re system alloy. The results are compared with the pure nickel. Operational tests of the thin-filmed resistors, having (NR10-VP) alloy contacts, showed that the departure of the resistors nominals is almost twice as small as that for the resistors, having pure nickel contacts. The use of this alloy permits to increase the thermal stability and durability of the TFRs, if they are used under extreme conditions

  8. Does 6 Hours of Contact With Alginate Impression Material Affect Dental Cast Properties?

    Science.gov (United States)

    Ibrahim, Amna Adam; Alhajj, Mohammed Nasser; Khalifa, Nadia; Gilada, Magdi Wadie

    2017-06-01

    Alginate impression (irreversible hydrocolloid) material is commonly used in dental practice because it is easy to mix, low in cost, and well tolerated by patients. The material is not dimensionally stable, however; thus, it is necessary to pour the impression immediately after the molding is accomplished, or within 60 minutes if the impression is kept in 100% humidity. Excessive contact of the alginate impression with the cast model over time may affect the model's properties. In this study, the authors tested the effect of contact time between an alginate impression and type III dental stone on cast model properties. Sixty-seven cast models were obtained from a stainless steel cylinder by using irreversible hydrocolloid impression material and type III dental stone. Thirty-seven cast models were separated from the impression after 1 hour (control group) and 30 cast models were separated after 6 hours (study group). The samples were evaluated under light microscope for surface details and measured by digital caliper for dimensional stability. An indentation on the cast was made and the depth of the indentation was then measured with a digital caliper to measure hardness. The dimensional stability of the cast models was not affected when contact time was increased from 1 hour to 6 hours (P = .507). Surface details did not deteriorate when contact time was increased, as all of the samples could reproduce all details after the 1-hour and 6-hour interval periods. However, hardness was greater after 1 hour of contact time (P = .001) than after 6 hours of contact time. In conclusion, contact between alginate impression material and type III dental stone up to 6 hours did not affect the dimensional stability and richness of the surface; hardness, though, was significantly affected.

  9. Cleanability evaluation of ceramic glazes with nanometer far-infrared materials using contact angle measurement.

    Science.gov (United States)

    Wang, Lijuan; Liang, Jinsheng; Di, Xingfu; Tang, Qingguo

    2014-05-01

    The cleanability of easy-to-clean ceramic glazes doped with nanometer far-infrared materials was compared with that of some high-quality household ceramic glazes from the market. The cleanability was evaluated by the contact angle measurement using a sessile drop method with a Dataphysics OCA-30 contact angle analyzer. The results showed that the difference of contact angles of water on the glazes before soiling and after cleaning could be used as a parameter for evaluating the cleanability of the glazes. The relationship between cleanability and surface properties, such as surface free energy and surface topography, was investigated. The surface free energy of the samples and their components were calculated using van Oss acid-base approach. By measuring advancing and receding contact angles, the contact angle hysteresis of the ceramic glazes due to the surface topography was investigated. It was shown that the cleanability of ceramic glazes containing nanometer far-infrared materials (NFIM) is better than that of household ceramic glazes from market, due to a higher ratio of electron-acceptor parameter to electron-donor parameter, which led to the effect of water hydration as well as better hydrophilic property and increased smoothness. The contact angle measurement not only accurately evaluates the cleanability of the ceramic glazes, but also has a contribution to the study of cleanability theory. Moreover, this method is simple, convenient and less sample-consumption.

  10. Processing and properties of silver-metal oxide electrical contact materials

    Directory of Open Access Journals (Sweden)

    Nadežda M. Talijan

    2012-12-01

    Full Text Available The presented study gives a brief overview of the experimental results of investigations of different production technologies of silver-metal oxide electrical contact materials in relation: processing method - properties. The two most common routes of production, i.e. internal oxidation/ingot metallurgy and powder metallurgy are demonstrated on the example of Ag-CdO and Ag-ZnO materials. For illustration of alternative processing routes that provide higher dispersion of metal-oxide particles in silver matrix more environmentally friendly Ag-SnO2 contact materials are used. Processing of electrical contact materials by mechanical mixing of starting powders in high energy ball mill is presented. The obtained experimental results of application of different methods of introduction of SnO2 nanoparticles in the silver matrix such as conventional powder metallurgy mixing and template method are given and discussed in terms of their influence on microstructure and physical properties (density, hardness and electrical conductivity of the prepared Ag-SnO2 electrical contact materials.

  11. Bacterial adhesion to conventional hydrogel and new silicone-hydrogel contact lens materials.

    Science.gov (United States)

    Kodjikian, Laurent; Casoli-Bergeron, Emmanuelle; Malet, Florence; Janin-Manificat, Hélène; Freney, Jean; Burillon, Carole; Colin, Joseph; Steghens, Jean-Paul

    2008-02-01

    As bacterial adhesion to contact lenses may contribute to the pathogenesis of keratitis, the aim of our study was to investigate in vitro adhesion of clinically relevant bacteria to conventional hydrogel (standard HEMA) and silicone-hydrogel contact lenses using a bioluminescent ATP assay. Four types of unworn contact lenses (Etafilcon A, Galyfilcon A, Balafilcon A, Lotrafilcon B) were incubated with Staphylococcus epidermidis (two different strains) and Pseudomonas aeruginosa suspended in phosphate buffered saline (PBS). Lenses were placed with the posterior surface facing up and were incubated in the bacterial suspension for 4 hours at 37 degrees C. Bacterial binding was then measured and studied by bioluminescent ATP assay. Six replicate experiments were performed for each lens and strain. Adhesion of all species of bacteria to standard HEMA contact lenses (Etafilcon A) was found to be significantly lower than that of three types of silicone-hydrogel contact lenses, whereas Lotrafilcon B material showed the highest level of bacterial binding. Differences between species in the overall level of adhesion to the different types of contact lenses were observed. Adhesion of P. aeruginosa was typically at least 20 times greater than that observed with both S. epidermidis strains. Conventional hydrogel contact lenses exhibit significantly lower bacterial adhesion in vitro than silicone-hydrogel ones. This could be due to the greater hydrophobicity but also to the higher oxygen transmissibility of silicone-hydrogel lenses.

  12. Graphical assessment of the linear contact steel on composite material at high temperature and pressure

    Science.gov (United States)

    Rus, Dorin; Florescu, Virgil; Bausic, Florin; Ursache, Robert; Sasu, Anca

    2018-01-01

    In this article we have tried to present a graphical assessment of the dry linear contact for composite materials reinforced with glass fibers as well as of the influence of the sliding speed, load and friction coefficient. Perpendicular loads, the contact temperature and the wear of the metal surface were recorded. The wear volume was calculated using the Archard relationship. Using the Archard relationship, the width of trace can be calculated in 3 locations. Numerous experimental trials were performed in connection to the wear of the metal surface, the contact temperature and the value of the friction coefficient. A connection between the evolution of the wear process and the dependency on the contact temperature and friction coefficient can be observed.

  13. Novel Sn-Based Contact Structure for GeTe Phase Change Materials.

    Science.gov (United States)

    Simchi, Hamed; Cooley, Kayla A; Ding, Zelong; Molina, Alex; Mohney, Suzanne E

    2018-05-16

    Germanium telluride (GeTe) is a phase change material (PCM) that has gained recent attention because of its incorporation as an active material for radio frequency (RF) switches, as well as memory and novel optoelectronic devices. Considering PCM-based RF switches, parasitic resistances from Ohmic contacts can be a limiting factor in device performance. Reduction of the contact resistance ( R c ) is therefore critical for reducing the on-state resistance to meet the requirements of high-frequency RF applications. To engineer the Schottky barrier between the metal contact and GeTe, Sn was tested as an interesting candidate to alter the composition of the semiconductor near its surface, potentially forming a narrow band gap (0.2 eV) SnTe or a graded alloy with SnTe in GeTe. For this purpose, a novel contact stack of Sn/Fe/Au was employed and compared to a conventional Ti/Pt/Au stack. Two different premetallization surface treatments of HCl and deionized (DI) H 2 O were employed to make a Te-rich and Ge-rich interface, respectively. Contact resistance values were extracted using the refined transfer length method. The best results were obtained with DI H 2 O for the Sn-based contacts but HCl treatment for the Ti/Pt/Au contacts. The as-deposited contacts had the R c (ρ c ) of 0.006 Ω·mm (8 × 10 -9 Ω·cm 2 ) for Sn/Fe/Au and 0.010 Ω·mm (3 × 10 -8 Ω·cm 2 ) for Ti/Pt/Au. However, the Sn/Fe/Au contacts were thermally stable, and their resistance decreased further to 0.004 Ω·mm (4 × 10 -9 Ω·cm 2 ) after annealing at 200 °C. In contrast, the contact resistance of the Ti/Pt/Au stack increased to 0.012 Ω·mm (4 × 10 -8 Ω·cm 2 ). Transmission electron microscopy was used to characterize the interfacial reactions between the metals and GeTe. It was found that formation of SnTe at the interface, in addition to Fe diffusion (doping) into GeTe, is likely responsible for the superior performance of Sn/Fe/Au contacts, resulting in one of the lowest reported

  14. Host cell capable of producing enzymes useful for degradation of lignocellulosic material

    Energy Technology Data Exchange (ETDEWEB)

    Los, Alrik Pieter; Sagt, Cornelis Maria Jacobus; Schoonneveld-Bergmans, Margot Elisabeth Francoise; Damveld, Robbertus Antonius

    2017-08-22

    The invention relates to a host cell comprising at least four different heterologous polynucleotides chosen from the group of polynucleotides encoding cellulases, hemicellulases and pectinases, wherein the host cell is capable of producing the at least four different enzymes chosen from the group of cellulases, hemicellulases and pectinases, wherein the host cell is a filamentous fungus and is capable of secretion of the at least four different enzymes. This host cell can suitably be used for the production of an enzyme composition that can be used in a process for the saccharification of cellulosic material.

  15. Host cell capable of producing enzymes useful for degradation of lignocellulosic material

    Science.gov (United States)

    Los, Alrik Pieter; Sagt, Cornelis Maria Jacobus; Schooneveld-Bergmans, Margot Elisabeth Francoise; Damveld, Robbertus Antonius

    2015-08-18

    The invention relates to a host cell comprising at least four different heterologous polynucleotides chosen from the group of polynucleotides encoding cellulases, hemicellulases and pectinases, wherein the host cell is capable of producing the at least four different enzymes chosen from the group of cellulases, hemicellulases and pectinases, wherein the host cell is a filamentous fungus and is capable of secretion of the at least four different enzymes. This host cell can suitably be used for the production of an enzyme composition that can be used in a process for the saccharification of cellulosic material.

  16. A frictional contact problem with wear involving elastic-viscoplastic materials with damage and thermal effects

    Directory of Open Access Journals (Sweden)

    Abdelmoumene Djabi

    2015-05-01

    Full Text Available We consider a mathematical problem for quasistatic contact between a thermo-elastic-viscoplastic body with damage and an obstacle. The contact is frictional and bilateral with a moving rigid foundation which results in the wear of the contacting surface. We employ the thermo-elasticviscoplastic with damage constitutive law for the material. The damage of the material caused by elastic deformations. The evolution of the damage is described by an inclusion of parabolic type. The problem is formulated as a coupled system of an elliptic variational inequality for the displacement, a parabolic variational inequality for the damage and the heat equation for the temperature. We establish a variational formulation for the model and we prove the existence of a unique weak solution to the problem. The proof is based on a classical existence and uniqueness result on parabolic inequalities, differential equations and fixed point arguments.

  17. Aspects Concerning Modelling Contact Pressure of Polymeric Materials Used in Robotic Soft Elements

    Directory of Open Access Journals (Sweden)

    Florina-Carmen Ciornei

    2015-06-01

    Full Text Available Compliant materials are used in applications of robotics for final elements of robotic systems. Contact pressure between a spherical indenter and a linear viscoelastic halfspace is modeled for a cosine normal load. The Maxwell viscoelastic halfspace is described by relaxation function and creep function. For the working frequency domain, the material does not present obvious relaxation. Only for very low frequencies, the pressure variation presents a maximum during approaching delayed with respect to maximum force

  18. Existence of solutions for quasistatic problems of unilateral contact with nonlocal friction for nonlinear elastic materials

    Directory of Open Access Journals (Sweden)

    Alain Mignot

    2005-09-01

    Full Text Available This paper shows the existence of a solution of the quasi-static unilateral contact problem with nonlocal friction law for nonlinear elastic materials. We set up a variational incremental problem which admits a solution, when the friction coefficient is small enough, and then by passing to the limit with respect to time we obtain a solution.

  19. Business contacts materials for developing listening and speaking skills for the student of business English

    CERN Document Server

    Brieger, N; Hughes, S; West, C

    1985-01-01

    Business Contacts provides classroom or self-study practice in communication skills for the specialist and non-specialist student of business English. The material is designed for adult learners of lower intermediate level and above who wish to revise their language or re-apply it in a business context.

  20. Enforcement of the Danish Bisphenol A restriction on Food Contact Materials and Articles for infants

    DEFF Research Database (Denmark)

    Pedersen, Gitte Alsing; Foverskov, Annie; Petersen, Jens Højslev

    In Denmark a national restriction was implemented in 2010 banning the use of bisphenol A (BPA) in any Food Contact Materials intended for children in the age 0-3 years. The ban includes BPA in baby bottles, baby cups, food cans for infant formulas and lids for glass containers with baby food...

  1. Treatment, material, care, and patient-related factors in contact lens-related dry eye.

    Science.gov (United States)

    Ramamoorthy, Padmapriya; Sinnott, Loraine T; Nichols, Jason J

    2008-08-01

    To examine the effect of general contact lens and material characteristics, care solutions, treatment, and patient-related factors on contact lens-related dry eye. The data were derived from the Contact Lens and Dry Eye Study, designed as a cross-sectional and nested case-control study including 360 subjects. In separate statistical models, logistic regression was used to examine general contact lens characteristics, specific hydrogel lens materials, care solutions, and patient-related factors associated with dry eye status (controlled for age, gender, and current treatments). Several factors were significantly associated with dry eye, including treatment factors such as a recent contact lens refitting (odds ratios [OR] = 5.75, 95% confidence intervals [CI] = 2.14 to 15.46) and use of artificial tears/rewetting drops (OR = 1.09, 95% CI = 1.02 to 1.16), in addition, currently worn materials including Food and Drug Administration (FDA) group II (OR = 2.98, 95% CI = 1.14 to 6.19) and IV (OR = 1.87, 95% CI = 1.08 to 3.24). Significant patient-related factors included decreased overall satisfaction (OR = 3.57, 95% CI = 2.08 to 5.88,), dry eye in the absence of contact lens wear (OR = 6.54, 95% CI = 2.57 to 16.62), reduced daily lens wear duration (OR = 1.16, 95% CI = 1.06 to 1.26), and reduced ability to wear lenses as long as desired (OR = 2.44, 95% CI = 1.30 to 4.54). Care solutions were not associated with contact lens-related dry eye. The strong association of common treatment factors with dry eye status in contact lens wearers suggests that these treatments are not entirely effective. The use of high water content materials was strongly related to dry eye in lens wearers, whereas care solutions were not. Contact lens-related dry eye was also associated with several patient-related factors such as greater ocular discomfort (without lenses), dissatisfaction, and inability to wear lenses for desired durations.

  2. Enzymatic hydrolysis of steam-pretreated lignocellulosic materials with Trichoderma atroviride enzymes produced in-house

    Directory of Open Access Journals (Sweden)

    Macrelli Stefano

    2009-07-01

    Full Text Available Abstract Background Improvement of the process of cellulase production and development of more efficient lignocellulose-degrading enzymes are necessary in order to reduce the cost of enzymes required in the biomass-to-bioethanol process. Results Lignocellulolytic enzyme complexes were produced by the mutant Trichoderma atroviride TUB F-1663 on three different steam-pretreated lignocellulosic substrates, namely spruce, wheat straw and sugarcane bagasse. Filter paper activities of the enzymes produced on the three materials were very similar, while β-glucosidase and hemicellulase activities were more dependent on the nature of the substrate. Hydrolysis of the enzyme preparations investigated produced similar glucose yields. However, the enzymes produced in-house proved to degrade the xylan and the xylose oligomers less efficiently than a commercial mixture of cellulase and β-glucosidase. Furthermore, accumulation of xylose oligomers was observed when the TUB F-1663 supernatants were applied to xylan-containing substrates, probably due to the low β-xylosidase activity of the enzymes. The efficiency of the enzymes produced in-house was enhanced by supplementation with extra commercial β-glucosidase and β-xylosidase. When the hydrolytic capacities of various mixtures of a commercial cellulase and a T. atroviride supernatant produced in the lab were investigated at the same enzyme loading, the glucose yield appeared to be correlated with the β-glucosidase activity, while the xylose yield seemed to be correlated with the β-xylosidase level in the mixtures. Conclusion Enzyme supernatants produced by the mutant T. atroviride TUB F-1663 on various pretreated lignocellulosic substrates have good filter paper activity values combined with high levels of β-glucosidase activities, leading to cellulose conversion in the enzymatic hydrolysis that is as efficient as with a commercial cellulase mixture. On the other hand, in order to achieve good xylan

  3. A general overview of support materials for enzyme immobilization: Characteristics, properties, practical utility

    DEFF Research Database (Denmark)

    Zdarta, Jakub; Meyer, Anne S.; Jesionowski, Teofil

    2018-01-01

    on the properties of the produced catalytic system. A large variety of inorganic and organic as well as hybrid and composite materials may be used as stable and efficient supports for biocatalysts. This review provides a general overview of the characteristics and properties of the materials applied for enzyme...... immobilization. For the purposes of this literature study, support materials are divided into two main groups, called Classic and New materials. The review will be useful in selection of appropriate support materials with tailored properties for the production of highly effective biocatalytic systems for use...

  4. Dynamic and impact contact mechanics of geologic materials: Grain-scale experiments and modeling

    International Nuclear Information System (INIS)

    Cole, David M.; Hopkins, Mark A.; Ketcham, Stephen A.

    2013-01-01

    High fidelity treatments of the generation and propagation of seismic waves in naturally occurring granular materials is becoming more practical given recent advancements in our ability to model complex particle shapes and their mechanical interaction. Of particular interest are the grain-scale processes that are activated by impact events and the characteristics of force transmission through grain contacts. To address this issue, we have developed a physics based approach that involves laboratory experiments to quantify the dynamic contact and impact behavior of granular materials and incorporation of the observed behavior indiscrete element models. The dynamic experiments do not involve particle damage and emphasis is placed on measured values of contact stiffness and frictional loss. The normal stiffness observed in dynamic contact experiments at low frequencies (e.g., 10 Hz) are shown to be in good agreement with quasistatic experiments on quartz sand. The results of impact experiments – which involve moderate to extensive levels of particle damage – are presented for several types of naturally occurring granular materials (several quartz sands, magnesite and calcium carbonate ooids). Implementation of the experimental findings in discrete element models is discussed and the results of impact simulations involving up to 5 × 105 grains are presented.

  5. Dynamic and impact contact mechanics of geologic materials: Grain-scale experiments and modeling

    Energy Technology Data Exchange (ETDEWEB)

    Cole, David M.; Hopkins, Mark A.; Ketcham, Stephen A. [Engineer Research and Development Center - Cold Regions Research and Engineering Laboratory, 72 Lyme Rd., Hanover, NH 03755 (United States)

    2013-06-18

    High fidelity treatments of the generation and propagation of seismic waves in naturally occurring granular materials is becoming more practical given recent advancements in our ability to model complex particle shapes and their mechanical interaction. Of particular interest are the grain-scale processes that are activated by impact events and the characteristics of force transmission through grain contacts. To address this issue, we have developed a physics based approach that involves laboratory experiments to quantify the dynamic contact and impact behavior of granular materials and incorporation of the observed behavior indiscrete element models. The dynamic experiments do not involve particle damage and emphasis is placed on measured values of contact stiffness and frictional loss. The normal stiffness observed in dynamic contact experiments at low frequencies (e.g., 10 Hz) are shown to be in good agreement with quasistatic experiments on quartz sand. The results of impact experiments - which involve moderate to extensive levels of particle damage - are presented for several types of naturally occurring granular materials (several quartz sands, magnesite and calcium carbonate ooids). Implementation of the experimental findings in discrete element models is discussed and the results of impact simulations involving up to 5 Multiplication-Sign 105 grains are presented.

  6. A novel method for the determination of migration of contaminants from food contact materials

    International Nuclear Information System (INIS)

    Thompson, D.; Parry, S.J.; Benzing, R.

    1996-01-01

    A neutron activation method has been developed for the analysis of high density polyethylene, low density polyethylene, polypropylene, polyethylene terephthalate and polystyrene food contact plastics. The method provides determination of over 50 elements at concentrations below 1 mg kg -1 . This technique has now been extended to study migration from food contact materials into standard food simulants (olive oil, acetic acid, ethanol and water). Samples of plastic are irradiated in a thermal neutron flux to procedure radionuclides of the elements present in the plastic. (author). 5 refs., 7 tabs

  7. Selection of contact bearing couple materials for hip prosthesis using finite element analysis under static conditions

    Science.gov (United States)

    Arirajan, K. A.; Chockalingam, K.; Vignesh, C.

    2018-04-01

    Implants are the artificial parts to replace the missing bones or joints in human anatomy to give mechanical support. Hip joint replacement is an important issue in orthopaedic surgery. The main concern limiting the long-run success of the total hip replacement is the limited service life. Hip replacement technique is widely used in replacing the femur head and acetabular cup by materials that are highly biocompatible. The success of the artificial hip replacement depends upon proper material selection, structure, and shape of the hip prosthesis. Many orthopaedic analyses have been tried with different materials, but ended with partial success on the application side. It is a critical task for selecting the best material pair in the hip prosthesis design. This work develops the finite element analysis of an artificial hip implant to study highest von Mises stress, contact pressure and elastic strain occurs for the dissimilar material combination. The different bearing couple considered for the analysis are Metal on Metal, Metal on Plastic, Metal on Ceramic, Ceramic on Plastic, Ceramic on Ceramic combinations. The analysis is carried out at different static positions of a human (i.e) standing, sitting. The results reveals that the combination with metal in contact with plastic (i.e) Titanium femoral head paired with Ultra High Molecular Weight Poly Ethylene acetabular cup reduces maximum von Mises stress and also it gives lowest contact pressure than other combination of bearing couples.

  8. Prediction of serviceability of the material working under conditions of dynamic contact with liquid medium

    International Nuclear Information System (INIS)

    Veksler, Yu.G.; Poluyanov, V.B.

    1977-01-01

    A method is suggested for selecting materials working in contact with fusible liquid metals under namic loading. It is recommended to determine the rate of failure in short-time tests of materials which have shown good corrosion resistence. A material thus selected is subject to short-time cavitation mechanical strength test and a creep test. After that the cavitation-mechanical strength is to be calculated with an account for variation of transverse cross-section area. An equation of cavitation failure rate vs. time is given

  9. Studies on Development of Polymeric Materials Using Gamma Irradiation for Contact and Intraocular Lenses

    Directory of Open Access Journals (Sweden)

    Pranshu Chhabra

    2009-01-01

    Full Text Available For the development of materials for contact lenses and intraocular lenses, the selection criteria is based on the (i capacity to absorb and retain water, (ii hydrophilicity and hydrophobicity, (iii refractive index and (iv hardness besides the other essential properties. Various monomers are being studied to develop suitable materials for such applications. Selection of suitable monomers that can be converted into optical materials of desired characteristics is the most essential step. In the present paper, an attempt has been made to develop suitable optical polymers based on 2-hydroxy ethyl methacrylate (HEMA, N-vinyl pyrrolidone (NVP, methyl methacrylate (MMA, methacrylic acid (MAA, and styrene. Compositions were prepared in such a way that polymers of varying hydrophilicity or hydrophobicity could be obtained keeping HEMA as the base (main monomer. For polymerization, gamma irradiation (Co-60 as a source was used. The results of the study showed that: (i an increase in NVP and MAA content brought in an increase in hydrophilicity of polymerized HEMA (pHEMA, while the addition of styrene and MMA decreased hydrophilicity of polymerized HEMA (pHEMA, (ii polymers for contact lenses with water retention capacity as high as >50 wt.% and as low as <10 wt% with varying content of suitable comonomers can be designed, (iii polymeric materials for contact lenses can be made by using radiation processing such as Co-60 and (iv a dose of 40 kGy was found to be ideal for purpose.

  10. [Determination of photoinitiators in printing inks used in food contact materials].

    Science.gov (United States)

    Han, Wei; Yu, Yanjun; Li, Ningtao; Wang, Libing

    2011-05-01

    A new analytical method based on gas chromatography-mass spectrometry (GC-MS) techniques was developed for the determination of five photoinitiators (PIs), benzophenone (BP), 4-methylbenzophenone (MBP), ethyl-4-dimethylaminobenzoate (EDAB), 2-ethylhexyl-4-dimethylaminobenzoate (EHDAB) and 1-hydroxycyclohexyl phenyl ketone (Irgacure 184), in the printing inks used in food contact materials. The test solutions were extracted from selected food contact materials using Soxhlet extractor with ethyl acetate as the extraction solvent. By adding 50 and 200 microg/L of a standard mixture of photoinitiators into the extracts of the blank packaging materials, the recoveries obtained were in the range of 66.7%-89.4%. The repeatability of the method was assessed by determining the contents of the photoinitiators in five types of food contact materials, and the results were lower than 10%. The instrumental detection limits (IDLs) and method quantification limits (MQLs) were in the range of 2.9-6.0 microg/L and 0.0017-0.0036 mg/dm2, respectively. The method was applied in the analysis of about twenty real samples (yogurt carton, milk carton, fruit juice carton and plastic bags samples). The most significant pollutants were BP and MBP. The concentrations of Irgacure 184, EDAB and EHDAB found in three individual samples were 0.84 mg/dm2, 0.2 mg/dm2 and 1.2 mg/dm2, respectively. The work proposed a new method to analyze the migration level of initiators from the inks.

  11. Steady-State Diffusion of Water through Soft-Contact LensMaterials

    Energy Technology Data Exchange (ETDEWEB)

    Fornasiero, Francesco; Krull, Florian; Radke, Clayton J.; Prausnitz, JohnM.

    2005-01-31

    Water transport through soft contact lenses (SCL) is important for acceptable performance on the human eye. Chemical-potential gradient-driven diffusion rates of water through soft-contact-lens materials are measured with an evaporation-cell technique. Water is evaporated from the bottom surface of a lens membrane by impinging air at controlled flow rate and humidity. The resulting weight loss of a water reservoir covering the top surface of the contact-lens material is recorded as a function of time. New results are reported for a conventional hydrogel material (SofLens{trademark} One Day, hilafilcon A, water content at saturation W{sub 10} = 70 weight %) and a silicone hydrogel material (PureVision{trademark}, balafilcon A, W{sub 10} = 36 %), with and without surface oxygen plasma treatment. Also, previously reported data for a conventional HEMA-SCL (W{sub 10} = 38 %) hydrogel are reexamined and compared with those for SofLens{trademark} One Day and PureVision{trademark} hydrogels. Measured steady-state water fluxes are largest for SofLens{trademark} One Day, followed by PureVision{trademark} and HEMA. In some cases, the measured steady-state water fluxes increase with rising relative air humidity. This increase, due to an apparent mass-transfer resistance at the surface (trapping skinning), is associated with formation of a glassy skin at the air/membrane interface when the relative humidity is below 55-75%. Steady-state water-fluxes are interpreted through an extended Maxwell-Stefan diffusion model for a mixture of species starkly different in size. Thermodynamic nonideality is considered through Flory-Rehner polymer-solution theory. Shrinking/swelling is self-consistently modeled by conservation of the total polymer mass. Fitted Maxwell-Stefan diffusivities increase significantly with water concentration in the contact lens.

  12. Contact mechanics at nanometric scale using nanoindentation technique for brittle and ductile materials.

    Science.gov (United States)

    Roa, J J; Rayon, E; Morales, M; Segarra, M

    2012-06-01

    In the last years, Nanoindentation or Instrumented Indentation Technique has become a powerful tool to study the mechanical properties at micro/nanometric scale (commonly known as hardness, elastic modulus and the stress-strain curve). In this review, the different contact mechanisms (elastic and elasto-plastic) are discussed, the recent patents for each mechanism (elastic and elasto-plastic) are summarized in detail, and the basic equations employed to know the mechanical behaviour for brittle and ductile materials are described.

  13. Comparison of properties of silver-metal oxide electrical contact materials

    Directory of Open Access Journals (Sweden)

    Ćosović V.

    2012-01-01

    Full Text Available Changes in physical properties such as density, porosity, hardness and electrical conductivity of the Ag-SnO2 and Ag-SnO2In2O3 electrical contact materials induced by introduction of metal oxide nanoparticles were investigated. Properties of the obtained silver-metal oxide nanoparticle composites are discussed and presented in comparison to their counterparts with the micro metal oxide particles as well as comparable Ag-SnO2WO3 and Ag-ZnO contact materials. Studied silvermetal oxide composites were produced by powder metallurgy method from very fine pure silver and micro- and nanoparticle metal oxide powders. Very uniform microstructures were obtained for all investigated composites and they exhibited physical properties that are comparable with relevant properties of equivalent commercial silver based electrical contact materials. Both Ag-SnO2 and Ag- SnO2In2O3 composites with metal oxide nanoparticles were found to have lower porosity, higher density and hardness than their respective counterparts which can be attributed to better dispersion hardening i.e. higher degree of dispersion of metal oxide in silver matrix.

  14. Selection Criteria and Methods for Testing Different Surface Materials for Contact Frying Processes

    DEFF Research Database (Denmark)

    Ashokkumar, Saranya

    Inner surfaces of industrial process equipment for food are often coated to give the surfaces particular properties with respect to adhesion and cleanability. Existing coating materials (PTFE (Teflon®) or silicone based polymers) suffer from drawbacks when used in contact frying, because these co...... surface materials for contact frying processes. The surfaces selected for this purpose cover a wide spectrum of materials that range from hydrophobic to hydrophilic materials. The different surface materials investigated include stainless steel (reference), aluminium (Al Mg 5754), PTFE......, an experimental rig has been constructed which enabled a controlled fouling of different coatings on steel and aluminium substrates under realistic frying conditions. A subjective rating procedure was employed for screening different surfaces according to their non-stick properties when used for frying of a model...... defects and surface roughness play a significant role. The wear resistance of the coatings was tested by performing abrasive wear experiments. The ceramic coatings: TiAlN and ZrN were found to show the best wear resistance properties. The experiments also revealed the poor wear resistance of stainless...

  15. Oxygen permeability of the pigmented material used in cosmetic daily disposable contact lenses

    Directory of Open Access Journals (Sweden)

    Galas S

    2016-12-01

    Full Text Available Stephen Galas, Lenora L Copper Johnson & Johnson Vision Care Inc., Jacksonville, FL, USA Purpose: To evaluate the individual contributions of pigment colorant and packing solution containing polyvinyl pyrrolidone (PVP on the oxygen permeability (Dk of a cosmetic printed etafilcon A daily disposable contact lens packaged with PVP. Method: The oxygen transport of a contact lens is evaluated through the central optical zone of the lens. Cosmetic printed contact lenses contain pigment colorant in the periphery or mid-periphery of the lens. Therefore, to assess the impact of cosmetic print on oxygen permeability, special lenses need to be produced that contain the colorant within the central optical zone. This technique was used to obtain multiple measurements of nonedge-corrected Dk/t of both the center pigmented lens and its nonpigmented equivalent, using a polarographic measurement described in International Organization for Standardization (ISO 18369-4:2006(E, and the Dk derived for each measurement is corrected for edge effect. In addition, the edge-corrected Dk values of lenses made from the same monomer batch were measured. The lenses were packaged and autoclaved with and without proprietary technology which embeds PVP in the contact lens during autoclaving. The resulting Dk value of the printed lens material was then used with thickness data to generate true Dk/t profiles for a given lens power. Results: The edge-corrected Dk of the printed etafilcon A lens with offset pigment colorant was measured to be 19.7×10-11 (cm2/s (mL O2/mL·mmHg at 35°C. This was within ±20% tolerance range as specified in ISO 18369-2:2012(E for the edge-corrected Dk of the nonpigmented etafilcon A control lens evaluated during the same session, 19.5×10-11 (cm2/s (mL O2/mL·mmHg. The edge-corrected Dk values of the lenses packaged with PVP (mean 20.1, standard deviation [SD] 0.3 were also within the ±20% tolerance range compared to those packaged without PVP

  16. Recent Advances in Polymeric Materials Used as Electron Mediators and Immobilizing Matrices in Developing Enzyme Electrodes

    Directory of Open Access Journals (Sweden)

    Mambo Moyo

    2012-01-01

    Full Text Available Different classes of polymeric materials such as nanomaterials, sol-gel materials, conducting polymers, functional polymers and biomaterials have been used in the design of sensors and biosensors. Various methods have been used, for example from direct adsorption, covalent bonding, crossing-linking with glutaraldehyde on composites to mixing the enzymes or use of functionalized beads for the design of sensors and biosensors using these polymeric materials in recent years. It is widely acknowledged that analytical sensing at electrodes modified with polymeric materials results in low detection limits, high sensitivities, lower applied potential, good stability, efficient electron transfer and easier immobilization of enzymes on electrodes such that sensing and biosensing of environmental pollutants is made easier. However, there are a number of challenges to be addressed in order to fulfill the applications of polymeric based polymers such as cost and shortening the long laboratory synthetic pathways involved in sensor preparation. Furthermore, the toxicological effects on flora and fauna of some of these polymeric materials have not been well studied. Given these disadvantages, efforts are now geared towards introducing low cost biomaterials that can serve as alternatives for the development of novel electrochemical sensors and biosensors. This review highlights recent contributions in the development of the electrochemical sensors and biosensors based on different polymeric material. The synergistic action of some of these polymeric materials and nanocomposites imposed when combined on electrode during sensing is discussed.

  17. Oxygen permeability (Dk) of thirty-seven rigid contact lens materials.

    Science.gov (United States)

    Benjamin, William J; Cappelli, Quido A

    2002-02-01

    Oxygen permeability (Dk) was determined for 37 available rigid contact lens materials in a masked fashion. The results were compared with those of an earlier study that included different lots of 14 test materials assessed in the current study. Six lenses of different thicknesses in each test and reference material were obtained. Test materials were arranged in sets of six to eight materials per set. Each set of materials, with inclusion of at least two reference materials for the purpose of simultaneous calibration, was measured to obtain preliminary amperages. Four preliminary measures were performed per thickness, resulting in 24 per material, in a schedule designed to spread the potential effects of machine drift and other factors. The mean preliminary amperages were used to derive corrected Dk values according to American National Standards Institute (ANSI) Z80.20-1998, and the values were linearly calibrated using the measured and established Dk values of the reference materials. The resistance (t/Dk) vs. thickness (t) plots for the 37 test and seven reference materials were approximated linearly. In 54 of 57 linear regressions, the coefficients of determination (R2) were >0.96, and in 48 instances were >0.98. Fourteen Dk values from the current study and an earlier study were linearly correlated (R2 = 0.9846), with a slope close to unity (+1.056) and intercept close to zero (-0.292). Ten of the current values fell within 10% of their corresponding earlier values. Only three current Dk values fell outside of the ANSI Z80.20-1998 tolerance for Dk (+/-20%). Two of these Dk values met the product tolerance when an obvious outlying point was graphically identified and omitted from the linear resistance (t/Dk) vs. thickness (t) regression. Omission of a single outlying point from a linear resistance vs. thickness regression can help provide a more valid Dk value. The ANSI Z80.20-1998 tolerance of +/-20% on Dk and the measurement reproducibility of +/-10% were

  18. Thermodynamics and phase equilibria of ternary systems relevant to contact materials for compound semiconductors

    International Nuclear Information System (INIS)

    Ipser, H.; Richter, K.; Micke, K.

    1997-01-01

    In order to investigate the stability of ohmic contacts to compound semiconductors, it is necessary to know the phase equilibria in the corresponding multi-component systems. We are currently studying the phase equilibria and thermophysical properties of several ternary systems which are of interest in view of the use of nickel, palladium and platinum as contact materials for GaSb and InSb compound semiconductors: Ga-Ni-Sb, In-Ni-Sb, Ga-Pd-Sb and Ga-Pt-Sb. Phase equilibria are investigated by thermal analyses, X-ray powder diffraction methods as well as electron microprobe analysis. Thermodynamic properties are derived from vapour pressure measurements using an isopiestic method. It is planned to combine all information on phase equilibria and thermochemistry for the ternary and the limiting binary systems to perform an optimization of the ternary systems by computer calculations using standard software. (author)

  19. Mimicking heme enzymes in the solid state: metal-organic materials with selectively encapsulated heme.

    Science.gov (United States)

    Larsen, Randy W; Wojtas, Lukasz; Perman, Jason; Musselman, Ronald L; Zaworotko, Michael J; Vetromile, Carissa M

    2011-07-13

    To carry out essential life processes, nature has had to evolve heme enzymes capable of synthesizing and manipulating complex molecules. These proteins perform a plethora of chemical reactions utilizing a single iron porphyrin active site embedded within an evolutionarily designed protein pocket. We herein report the first class of metal-organic materials (MOMs) that mimic heme enzymes in terms of both structure and reactivity. The MOMzyme-1 class is based upon a prototypal MOM, HKUST-1, into which catalytically active metalloporphyrins are selectively encapsulated in a "ship-in-a-bottle" fashion within one of the three nanoscale cages that exist in HKUST-1. MOMs offer unparalleled levels of permanent porosity and their modular nature affords enormous diversity of structures and properties. The MOMzyme-1 class could therefore represent a new paradigm for heme biomimetic catalysis since it combines the activity of a homogeneous catalyst with the stability and recyclability of heterogeneous catalytic systems within a single material.

  20. Performance of mechanically shaken indirect contact atmospheric dryer in drying pastelike materials

    Directory of Open Access Journals (Sweden)

    K. P. Melo

    2004-09-01

    Full Text Available Pastelike materials are encountered in many technological processes in chemical, pharmaceutical, foodstuff and natural product industries. The most important factor in the drying of this type of materials is the nature of the moisture bonding that occurs. Because of the different characteristics of pastes, it is impossible to recommend a universal type of dryer for all of these materials. Some of the dryers available provide only indirect contact with the drying agent (heat and also maintain constant moisture with a system of rotating paddles. We evaluated the performance of this type by studying the dryer kinetics curves for ground coffee under a variety of operational conditions of moisture load of material, temperature of the heating plate, intensity of the mechanical mixing of the moisture material, and initial moisture. The effects of these parameters (except for moisture were studied using a 2³ factorial design. According the analyses of the kinetics drying curves, was observed that the increase in the temperature of the plate and rotation as well as the decrease in the load facilitates more effective removal of moisture. In statistical analysis was determined that the load of the material and the heating plate temperature influence the final moisture content of the material and plate temperature modifies the final temperature of the solid. Also, was suggested linear models from the factorial design to describe the process of drying coffee grounds satisfactorily.

  1. Hydro-thermal analysis of the sudden contact of two molten materials

    International Nuclear Information System (INIS)

    Elbeshbeshy, R.A.

    1982-01-01

    High pressure pulses can be generated when extremely hot molten material comes into contact with relatively cold molten material. Such high pressure is attributed to the rapid heat transfer rate between the two materials as a result of a fragmentation process of the hot material. A new mechanism of fragmentation is introduced based on a cavitation mechanism within the hot molten material. Cavitation in a liquid can occur either as a result of superheating the liquid or as a result of a negative pressure (hydrostatic tension) within the liquid. The results of the one-dimensional model in the present study indicates a large negative pressure pulse traveling away from the interface of the two molten materials. It is proposed that this negative pressure can be the driving mechanism for initiating the fragmentation process. This will then lead to an increase in the rate of heat transfer between the two materials, and to an explosion which is thermal in nature. A specific example of UO 2 -Na interactions is discussed

  2. Microstructural and Material Quality Effects on Rolling Contact Fatigue of Highly Elastic Intermetallic Ball Bearings

    Science.gov (United States)

    DellaCorte, Christopher; Howard, S. Adam; Thomas, Fransua; Stanford, Malcolm K.

    2016-01-01

    Rolling element bearings made from highly-elastic intermetallic materials (HIM)s, such as 60NiTi, are under development for applications that require superior corrosion and shock resistance. Compared to steel, intermetallics have been shown to have much lower rolling contact fatigue (RCF) stress capability in simplified 3-ball on rod (ASTM STP 771) fatigue tests. In the 3-ball tests, poor material quality and microstructural flaws negatively affect fatigue life but such relationships have not been established for full-scale 60NiTi bearings. In this paper, 3-ball-on-rod fatigue behavior of two quality grades of 60NiTi are compared to the fatigue life of full-scale 50mm bore ball bearings made from the same materials. 60NiTi RCF rods with material or microstructural flaws suffered from infant mortality failures at all tested stress levels while high quality 60NiTi rods exhibited no failures at lower stress levels. Similarly, tests of full-scale bearings made from flawed materials exhibited early surface fatigue and through crack type failures while bearings made from high quality material did not fail even in long-term tests. Though the full-scale bearing test data is yet preliminary, the results suggest that the simplified RCF test is a good qualitative predictor of bearing performance. These results provide guidance for materials development and to establish minimum quality levels required for successful bearing operation and life.

  3. Effects of coating process on the characteristics of Ag-SnO2 contact materials

    International Nuclear Information System (INIS)

    Liu, X.M.; Wu, S.L.; Chu, Paul K.; Chung, C.Y.; Zheng, J.; Li, S.L.

    2006-01-01

    Good wettability between the SnO 2 and silver matrix can improve the electrical contact performance of Ag-SnO 2 materials. In this work, Ag was deposited onto the surface of Ti-doped SnO 2 particles using chemical plating to enhance the wettability. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to characterize the Ag-coated SnO 2 particles. Scanning electron microscopy (SEM), conductivity tests, differential thermal analysis (DTA), and thermogravimetric analysis (TGA) were performed on the Ag-SnO 2 materials. Our results reveal that the chemical plating process can enhance the wettability between the Ti-doped SnO 2 particles and Ag matrix, and the Ag-coated SnO 2 particles are uniformly distributed in the Ag matrix. Both the thermal and electrical conductivity of the Ag-SnO 2 materials are significantly improved

  4. Inorganic Materials as Supports for Covalent Enzyme Immobilization: Methods and Mechanisms

    Directory of Open Access Journals (Sweden)

    Paolo Zucca

    2014-09-01

    Full Text Available Several inorganic materials are potentially suitable for enzymatic covalent immobilization, by means of several different techniques. Such materials must meet stringent criteria to be suitable as solid matrices: complete insolubility in water, reasonable mechanical strength and chemical resistance under the operational conditions, the capability to form manageable particles with high surface area, reactivity towards derivatizing/functionalizing agents. Non-specific protein adsorption should be always considered when planning covalent immobilization on inorganic solids. A huge mass of experimental work has shown that silica, silicates, borosilicates and aluminosilicates, alumina, titania, and other oxides, are the materials of choice when attempting enzyme immobilizations on inorganic supports. More recently, some forms of elemental carbon, silicon, and certain metals have been also proposed for certain applications. With regard to the derivatization/functionalization techniques, the use of organosilanes through silanization is undoubtedly the most studied and the most applied, although inorganic bridge formation and acylation with selected acyl halides have been deeply studied. In the present article, the most common inorganic supports for covalent immobilization of the enzymes are reviewed, with particular focus on their advantages and disadvantages in terms of enzyme loadings, operational stability, undesired adsorption, and costs. Mechanisms and methods for covalent immobilization are also discussed, focusing on the most widespread activating approaches (such as glutaraldehyde, cyanogen bromide, divinylsulfone, carbodiimides, carbonyldiimidazole, sulfonyl chlorides, chlorocarbonates, N-hydroxysuccinimides.

  5. The interaction between contacting barrier materials for containment of radioactive wastes

    International Nuclear Information System (INIS)

    Chang, Hao-Chun; Wang, Chun-Yao; Huang, Wei-Hsing

    2012-01-01

    Document available in extended abstract form only. The disposal of low-level radioactive wastes requires multi-barrier facilities to contain the wastes from contamination. Typically, the engineered barrier is composed of a concrete vault backfilled with sand/bentonite mixture. The backfill material is a mixture of bentonite and sand/gravel produced from crushing the rocks excavated at the site. With a great swelling potential, bentonite is expected to serve the sealing function, while the crushed sand/gravel improves the workability of the mixture. Due to the nature of radioactive wastes, the disposal site is designed for a service life of 300 years or more, which is much longer than typical engineering or earth works. With such a long service life, the site is subject to groundwater intrusion and geochemical evolution. The near-field environment evolution can be a complex problem in a disposal site. In the vicinity of the concrete vault in a disposal site, the high-alkali concrete environment can cause changes in the pore solution and alter the nature of backfill materials. Therefore, the interaction between the concrete and the backfill material needs to be assessed, such that the barriers serve the expected functions for a long time. Materials and Methods A locally available Zhishin clay and a bentonite originated from Black Hill, Wyoming, USA were used as raw clay materials in this study. Zhishin clay and Black Hill (BH) bentonite are mixed with Taitung area hard shale to produce the backfill material. An experimental program was conducted analysing the soil properties of these 2 bentonites. And an accelerated migration test was devised to understand the loss of calcium leaching of concrete on characteristics of backfill material. The 2 barrier materials (concrete and backfill) were placed in contact and then an electric gradient applied to accelerate the move of cations between the 2 barriers. Fig. 1 shows a schematic diagram of the accelerated migration test

  6. Evaluating skin-protective materials against contact irritants and allergens. An in vivo screening human model.

    Science.gov (United States)

    Zhai, H; Willard, P; Maibach, H I

    1998-03-01

    2 acute irritants and 1 allergen were selected: sodium lauryl sulfate (SLS) representative of irritant household and occupational contact dermatitis, the combination of ammonium hydroxide (NH4OH) and urea to simulate diaper dermatitis, and Rhus to evaluate the effect of model protective materials. The putative protective materials and vehicle were applied to both ventral forearms of 10 subjects in each group, according to a randomized code. Test materials were spread over a marked 2.0 cm2 area, massaged in, allowed to dry for 30 min, and reapplied with another 30 min drying period. The model irritants and allergen were then applied (0.025 ml) to an Al-test occlusive patch, which in turn was placed for 24 h over each of the 8 designated sites. Inflammation was scored according to a clinical scale 72 h post-application. Paraffin wax plus Acetulan in cetyl alcohol, and beeswax plus Acetulan in cetyl alcohol, markedly (p < 0.001) suppressed SLS irritation. Paraffin wax plus beeswax in cetyl alcohol, and Acetulan in cetyl alcohol reduced NH4OH and urea irritation (p < 0.05), paraffin wax in cetyl alcohol significantly (p < 0.01) decreasing Rhus allergic contact dermatitis. This model, provides an easy approach to screening protectants. Its clinical significance requires comparison with an open rather than an occluded challenge.

  7. Evaluation of the contact switch materials in high voltage power supply for generate of underwater shockwave by electrical discharge

    Directory of Open Access Journals (Sweden)

    K Higa

    2016-10-01

    Full Text Available We have developed the high voltage power-supply unit by Cockcroft-Walton circuit for ingenerate high pressure due to underwater shockwave by electrical discharge. This high voltage power supply has the problem of the metal contact switch operation that contact switch stop by melting and bonding due to electrical spark. We have studied the evaluation of materials of contact switch for the reducing electrical energy loss and the problem of contact switch operation. In this research, measurement of discharge voltage and high pressure due to underwater shockwave was carried out using the contact switch made of different materials as brass plate, brass-carbon plate-brass and carbon block. The contact switch made of carbon is effective to reduce energy loss and problem of contactor switch operation.

  8. Identification and risk assessment of unknown contaminants migrating from Food Contact Materials

    DEFF Research Database (Denmark)

    Pieke, Eelco Nicolaas

    The exposure of humans to possibly thousands of chemical compounds through food poses a health risk that is questioning our ability to ensure high standards for food safety. Food contact materials (FCM) are a major source of extraneous chemical compounds in food, yet not much knowledge is available...... interpretations. Risk prioritization is successful in classifying estimated risk based on predicted exposure and predicted hazard, and is valuable for to preliminary RA studies. The overarching strategy in this study shows that explorative techniques are valuable tools to help ensure food safety in the future...

  9. Short-term organic carbon migration from polymeric materials in contact with chlorinated drinking water.

    Science.gov (United States)

    Mao, Guannan; Wang, Yingying; Hammes, Frederik

    2018-02-01

    Polymeric materials are widely used in drinking water distribution systems. These materials could release organic carbon that supports bacterial growth. To date, the available migration assays for polymeric materials have not included the potential influence of chlorination on organic carbon migration behavior. Hence, we established a migration and growth potential protocol specifically for analysis of carbon migration from materials in contact with chlorinated drinking water. Four different materials were tested, including ethylene propylene dienemethylene (EPDM), poly-ethylene (PEX b and PEX c) and poly-butylene (PB). Chlorine consumption rates decreased gradually over time for EPDM, PEXc and PB. In contrast, no free chlorine was detected for PEXb at any time during the 7 migration cycles. Total organic carbon (TOC) and assimilable organic carbon (AOC) was evaluated in both chlorinated and non-chlorinated migrations. TOC concentrations for EPDM and PEXb in chlorinated migrations were significantly higher than non-chlorinated migrations. The AOC results showed pronounced differences among tested materials. AOC concentrations from chlorinated migration waters of EPDM and PB were higher compared to non-chlorinated migrations, whereas the opposite trend was observed for PEXb and PEXc. There was also a considerable difference between tested materials with regards to bacterial growth potential. The results revealed that the materials exposed to chlorine-influenced migration still exhibited a strong biofilm formation potential. The overall results suggested that the choice in material would make a considerable difference in chlorine consumption and carbon migration behavior in drinking water distribution systems. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Oxygen permeability of the pigmented material used in cosmetic daily disposable contact lenses.

    Science.gov (United States)

    Galas, Stephen; Copper, Lenora L

    2016-01-01

    To evaluate the individual contributions of pigment colorant and packing solution containing polyvinyl pyrrolidone (PVP) on the oxygen permeability (Dk) of a cosmetic printed etafilcon A daily disposable contact lens packaged with PVP. The oxygen transport of a contact lens is evaluated through the central optical zone of the lens. Cosmetic printed contact lenses contain pigment colorant in the periphery or mid-periphery of the lens. Therefore, to assess the impact of cosmetic print on oxygen permeability, special lenses need to be produced that contain the colorant within the central optical zone. This technique was used to obtain multiple measurements of nonedge-corrected Dk/t of both the center pigmented lens and its nonpigmented equivalent, using a polarographic measurement described in International Organization for Standardization (ISO) 18369-4:2006(E), and the Dk derived for each measurement is corrected for edge effect. In addition, the edge-corrected Dk values of lenses made from the same monomer batch were measured. The lenses were packaged and autoclaved with and without proprietary technology which embeds PVP in the contact lens during autoclaving. The resulting Dk value of the printed lens material was then used with thickness data to generate true Dk/t profiles for a given lens power. The edge-corrected Dk of the printed etafilcon A lens with offset pigment colorant was measured to be 19.7×10 -11 (cm 2 /s) (mL O 2 /mL·mmHg) at 35°C. This was within ±20% tolerance range as specified in ISO 18369-2:2012(E) for the edge-corrected Dk of the nonpigmented etafilcon A control lens evaluated during the same session, 19.5×10 -11 (cm 2 /s) (mL O 2 /mL·mmHg). The edge-corrected Dk values of the lenses packaged with PVP (mean 20.1, standard deviation [SD] 0.3) were also within the ±20% tolerance range compared to those packaged without PVP (mean 20.0, SD 0.3). The pigment colorant and PVP embedded in the contact lens during autoclaving were not found to

  11. Biofilm formation on materials into contact with water: hygienic and technical aspects

    International Nuclear Information System (INIS)

    Bonadonna, L; Memoli, G.; Chiaretti, G.

    2008-01-01

    Biofilm formation in man-made water systems has a hygienic concern when it is considered that the continuous detachment of this structure in the water flow, condition representing a potential source of contamination of plumbing and a risk for health, allows also pathogen microorganisms to reach consumers. The trend of biofilm formation was evaluated through series of microbiological analyses performed, under controlled conditions, on pipes made of materials that come into contact with drinking water according to the Decree of Ministry of Health n. 174. The investigation showed that, respect to the other materials, the reticulated polyethylene allows to sustain higher microorganisms concentrations. This characteristic was also observed in biofilms developed in condition of water stagnation compared to biofilm risen on surfaces of pipes under water flow [it

  12. Estrogen Receptor Binding Affinity of Food Contact Material Components Estimated by QSAR.

    Science.gov (United States)

    Sosnovcová, Jitka; Rucki, Marián; Bendová, Hana

    2016-09-01

    The presented work characterized components of food contact materials (FCM) with potential to bind to estrogen receptor (ER) and cause adverse effects in the human organism. The QSAR Toolbox, software application designed to identify and fill toxicological data gaps for chemical hazard assessment, was used. Estrogen receptors are much less of a lock-and-key interaction than highly specific ones. The ER is nonspecific enough to permit binding with a diverse array of chemical structures. There are three primary ER binding subpockets, each with different requirements for hydrogen bonding. More than 900 compounds approved as of FCM components were evaluated for their potential to bind on ER. All evaluated chemicals were subcategorized to five groups with respect to the binding potential to ER: very strong, strong, moderate, weak binder, and no binder to ER. In total 46 compounds were characterized as potential disturbers of estrogen receptor. Among the group of selected chemicals, compounds with high and even very high affinity to the ER binding subpockets were found. These compounds may act as gene activators and cause adverse effects in the organism, particularly during pregnancy and breast-feeding. It should be considered to carry out further in vitro or in vivo tests to confirm their potential to disturb the regulation of physiological processes in humans by abnormal ER signaling and subsequently remove these chemicals from the list of approved food contact materials. Copyright© by the National Institute of Public Health, Prague 2016

  13. [Role of the EFSA in risk management system regarding food contact materials and articles].

    Science.gov (United States)

    Cwiek-Ludwicka, Kazimiera; Półtorak, Hanna; Pawlicka, Marzena

    2009-01-01

    The role of the European Food Safety Authority (EFSA) in the risk management system regarding food contact materials and articles is related with the risk assessment of the substances for the European Commission. General rules for the authorisation of substances used in materials and articles intended to contact with food is established in the Regulation (EC) no 1935/2004. For the evaluation of substances their toxicological properties and magnitude of migration into food simulants is taken into account. Toxicological studies include the mutagenicity tests, oral toxicity studies, carcinogenicity, reproduction and also studies on absorption, distribution, metabolism and excretion of the substance and other studies when needed. The set of the relevant toxicological data for substance depends on the magnitude of migration. In the case of positive opinion by EFSA the substance appears on the Community list of authorised substances. Sometimes, the earlier evaluated and authorized substances must undergo re-evaluation due to their new toxicological properties or as a result of a presence in the food of their earlier unknown decomposition products. Examples of the selected substances which underwent re-evaluation by EFSA in the light of the current toxicological knowledge and the relevant activities undertaken by the European Commission have been presented.

  14. Materials And Carbon Flow In A Waste Refinery Process Using Enzymes

    DEFF Research Database (Denmark)

    Tonini, Davide; Woods, M.; Astrup, Thomas

    2011-01-01

    Recovery of resources from mixed Municipal Solid Waste (MSW) is a crucial aspect of waste management practices. In this paper the materials and carbon flows of an innovative waste refinery process using enzymes are presented. Through enzymatic treatment the process produces two main streams from...... the initial mixed MSW: a bioslurry (liquefied paper and organics) and a solid fraction (non-degradable materials). The discussion is based on the performance of the process in separating recyclables and recovery Cbiogenic as well as nutrients from the input MSW. The results of MFA and SFA illustrate...... that the waste refinery has great potential for resource recovery: about 100% of the Cbiogenic and up to 90% of N and P can potentially be recovered in the bioslurry and returned to land after anaerobic digestion. Recovery of ferrous and non-ferrous material is estimated double compared to recovering the same...

  15. Preparation and Characterization of Enzyme Compartments in UV-Cured Polyurethane-Based Materials and Their Application in Enzymatic Reactions

    Directory of Open Access Journals (Sweden)

    Diana Uhrich

    2017-11-01

    Full Text Available The preparation and characterization of UV-cured polyurethane-based materials for the mild inclusion immobilization of enzymes was investigated. Full curing of the polymer precursor/enzyme solution mixture was realized by a short irradiation with UV-light at ambient temperatures. The included aqueous enzyme solution remains highly dispersed in the polymer material with an even size distribution throughout the polymer material. The presented concept provides stable enzyme compartments which were applied for an alcohol dehydrogenase-catalyzed reduction reaction in organic solvents. Cofactor regeneration was achieved by a substrate-coupled approach via 2-propanol or an enzyme-coupled approach by a glucose dehydrogenase. This reaction concept can also be used for a simultaneous application of contrary biocatalytic reaction conditions within an enzymatic cascade reaction. Independent polymer-based reaction compartments were provided for two incompatible enzymatic reaction systems (alcohol dehydrogenase and hydroxynitrile lyase, while the relevant reactants diffuse between the applied compartments.

  16. In Vitro Effect of Lysozyme on Albumin Deposition to Hydrogel Contact Lens Materials.

    Science.gov (United States)

    Babaei Omali, Negar; Subbaraman, Lakshman N; Heynen, Miriam; Fadli, Zohra; Coles-Brennan, Chantal; Jones, Lyndon W

    2017-11-01

    Albumin deposition on contact lenses could be detrimental to contact lens (CL) wear because this may increase the risk of bacterial binding and reduce comfort. Lysozyme deposition on selected lens materials would reduce albumin deposition on lenses. This study aims to determine if lysozyme deposition on CLs could act as a barrier against subsequent albumin adsorption, using an in vitro model. Six hydrogel CL materials (etafilcon A, polymacon, nelfilcon A, omafilcon A, ocufilcon B, and nesofilcon A) were evaluated. Four CLs of each type were soaked in lysozyme solution for 16 hours at 37°C. Lysozyme-coated lenses were then placed in vials with 1.5 mL of artificial tear solution containing I-labeled albumin for 16 hours at 37°C with shaking. Four uncoated lenses of each type were used as controls. Lenses soaked in radiolabeled albumin were rinsed in a phosphate-buffered saline solution, and radioactive counts were measured directly on lenses using a gamma counter. Albumin uptake on lenses was measured using a calibration curve by plotting radioactive counts versus protein concentration. Results are reported as mean ± SD. Lysozyme-coated etafilcon A lenses exhibited lower levels of deposited albumin than uncoated etafilcon A lenses (58 ± 12 vs. 84 ± 5 ng/lens; P albumin adsorption between control (uncoated) and lysozyme-coated polymacon (105 ± 10 vs. 110 ± 34 ng/lens), nelfilcon A (51 ± 7 vs. 42 ± 20 ng/lens), omafilcon A (90 ± 20 vs. 80 ± 38 ng/lens), ocufilcon B (87 ± 20 vs. 115 ± 50 ng/lens), and nesofilcon A (170 ± 29 vs. 161 ± 10 ng/lens) lens materials (P > .05). Uncoated nesofilcon A lenses deposited the highest amount of albumin when compared with other uncoated lenses (P albumin, which may potentially be beneficial to CL wearers.

  17. Compositions for enhancing hydroysis of cellulosic material by cellulolytic enzyme compositions

    Science.gov (United States)

    Quinlan, Jason; Xu, Feng; Sweeney, Matthew; Johansen, Katja Salomon

    2014-09-30

    The present invention relates to compositions comprising a GH61 polypeptide having cellulolytic enhancing activity and an organic compound comprising a carboxylic acid moiety, a lactone moiety, a phenolic moiety, a flavonoid moiety, or a combination thereof, wherein the combination of the GH61 polypeptide having cellulolytic enhancing activity and the organic compound enhances hydrolysis of a cellulosic material by a cellulolytic enzyme compared to the GH61 polypeptide alone or the organic compound alone. The present invention also relates to methods of using the compositions.

  18. Oxygen, water, and sodium chloride transport in soft contact lenses materials.

    Science.gov (United States)

    Gavara, Rafael; Compañ, Vicente

    2017-11-01

    Oxygen permeability, diffusion coefficient of the sodium ions and water flux and permeability in different conventional hydrogel (Hy) and silicone-hydrogel (Si-Hy) contact lenses have been measured experimentally. The results showed that oxygen permeability and transmissibility requirements of the lens have been addressed through the use of siloxane containing hydrogels. In general, oxygen and sodium chloride permeability values increased with the water content of the lens but there was a percolation phenomenon from a given value of water uptake mainly in the Si-Hy lenses which appeared to be related with the differences between free water and bound water contents. The increase of ion permeability with water content did not follow a unique trend indicating a possible dependence of the chemical structure of the polymer and character ionic and non-ionic of the lens. Indeed, the salt permeability values for silicone hydrogel contact lenses were one order of magnitude below those of conventional hydrogel contact lenses, which can be explained by a diffusion of sodium ions occurring only through the hydrophilic channels. The increase of the ionic permeability in Si-Hy materials may be due to the confinement of ions in nanoscale water channels involving possible decreased degrees of freedom for diffusion of both water and ions. In general, ionic lenses presented values of ionic permeability and diffusivity higher than most non-ionic lenses. The tortuosity of the ionic lenses is lower than the non-ionic Si-Hy lenses. Frequency 55 and PureVision exhibited the highest water permeability and flux values and, these parameters were greater for ionic Si-Hy lenses than for ionic conventional hydrogel lenses. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2218-2231, 2017. © 2016 Wiley Periodicals, Inc.

  19. Determination of the total attenuation coefficient for six contact lens materials using the Beer-Lambert law.

    Science.gov (United States)

    Hull, C C; Crofts, N C

    1996-03-01

    The Beer-Lambert law has been used to determine the total attenuation coefficient, mu t, of three hard and three soft contact lens materials. The three hard contact lens materials were PMMA, Polycon II and Boston IV whereas the 3 soft materials were chosen with differing water contents of 38, 55 and 70%, respectively. The total attenuation coefficients of all six materials were obtained from measurements of the axial transmission at 632.8 nm of a series of plano powered lenses varying in axial thickness from 0.5 to 3.5 mm. The value of the total attenuation coefficient depends on both scattering and absorption and hence PMMA and Boston IV, which both incorporated a handling tint, showed significantly higher values (P 0.5) was found between any of the hydrated soft contact lens materials tested.

  20. FRICTIONLESS CONTACT IN A LAYERED PIEZOELECTRIC MEDIUM COMPOSED OF MATERIALS WITH HEXAGONAL SYMMETRY

    Directory of Open Access Journals (Sweden)

    Guillermo Ramírez

    Full Text Available A matrix formulation is presented for the solution of frictionless contact problems on arbitrarily multilayered piezoelectric half-planes. Different arrangements of elastic and transversely orthotropic piezoelectric materials within the multilayered medium are considered. A generalized plane deformation is used to obtain the governing equilibrium equations for each individual layer. These equations are solved using the infinite Fourier transform technique. The problem is then reformulated using the local/global stiffness method, in which a local stiffness matrix relating the stresses and electric displacement to the mechanical displacements and electric potential in the transformed domain is formulated for each layer. Then it is assembled into a global stiffness matrix for the entire half-plane by enforcing interfacial continuity of tractions and displacements. This local/global stiffness approach not only eliminates the necessity of explicitly finding the unknown Fourier coefficients, but also allows the use of efficient numerical algorithms, many of which have been developed for finite element analysis. Unlike finite element methods, the present approach requires minimal input. Application of the mixed boundary conditions reduces the problem to an integral equation. This integral equation is numerically solved for the unknown contact pressure using a technique based on the Chebyshev polynomials.

  1. Primary aromatic amines (PAAs) in black nylon and other food-contact materials, 2004-2009

    DEFF Research Database (Denmark)

    Trier, Xenia Thorsager; Okholm, B.; Foverskov, Annie

    2010-01-01

    Primary aromatic amines (PAAs) were analysed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in migrates from 234 samples of food-contact materials, including black nylon (polyamide) kitchen utensils (n = 136), coloured plastics (28), and clear/printed multilayer film/laminates (41......), from retailers, importers, and food producers. A further 29 utensils in use were obtained from colleagues. Very high PAA migration was found from black nylon kitchen utensils to the food simulant 3% acetic acid: the 'non-detectable' limit (20 mu g aniline equivalents kg-1 food) was exceeded by up...... migration test conditions influenced the final test results. Long-term release of PAAs was fitted by diffusion modelling experiments and long-term release was also seen as expected from used utensils. Toxicologists consider these migration levels of the suspected carcinogenic PAAs as a problem of major...

  2. Comparative exposure to DEHP from food contact materials: application of the product intake fraction

    DEFF Research Database (Denmark)

    Ernstoff, Alexi; Jolliet, Olivier; Fantke, Peter

    Quantitative Sustainability Assessment Food contact materials (FCM), e.g. bottles and food handling gloves, can contain potentially endocrine disrupting chemicals, such as di-2-ethylhexyl phthalate(DEHP, CAS: 117-81-7). To investigate the contribution of FCM to dietary DEHP exposure we apply...... thresholds. A hypothetical average PiF for the FCM sector was calculated via production volume and oral exposure doses estimated from NHANES data. In both cases the indication was gloves may contribute more to DEHP exposure when used with certain food items than bottled water. DEHP content in gloves greater...... than 5% would cause exceedance of US EPA threshold when used with certain food items,e.g. radishes based on PiF calculated here. The PiF used in thís context has applications for regulations related to FCM and exposure assessments on a per unit kilo basis....

  3. Improvement of the electrical contact resistance at rough interfaces using two dimensional materials

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Jianchen; Pan, Chengbin; Lanza, Mario, E-mail: mlanza@suda.edu.cn [Institute of Functional Nano & Soft Materials (FUNSOM), Collaborative Innovation Center of Suzhou Nanoscience and Technology, Soochow University, 199 Ren-Ai Road, Suzhou 215123 (China); Li, Heng [State Key Laboratory for Turbulence and Complex System, Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing 100871 (China); CAPT, HEDPS and IFSA Collaborative Innovation Center of MoE, Peking University, Beijing 100871 (China); Shen, Panpan; Sun, Hui; Duan, Huiling [State Key Laboratory for Turbulence and Complex System, Department of Mechanics and Engineering Science, CAPT, College of Engineering, Peking University, Beijing 100871 (China)

    2015-12-07

    Reducing the electronic contact resistance at the interfaces of nanostructured materials is a major goal for many kinds of planar and three dimensional devices. In this work, we develop a method to enhance the electronic transport at rough interfaces by inserting a two dimensional flexible and conductive graphene sheet. We observe that an ultra-thin graphene layer with a thickness of 0.35 nm can remarkably reduce the roughness of a sample in a factor of 40%, avoiding the use of thick coatings, leading to a more homogeneous current flow, and extraordinarily increasing the total current compared to the graphene-free counterpart. Due to its simplicity and performance enhancement, this methodology can be of interest to many interface and device designers.

  4. Process Knowledge Summary Report for Materials and Fuels Complex Contact-Handled Transuranic Debris Waste

    Energy Technology Data Exchange (ETDEWEB)

    R. P. Grant; P. J. Crane; S. Butler; M. A. Henry

    2010-02-01

    This Process Knowledge Summary Report summarizes the information collected to satisfy the transportation and waste acceptance requirements for the transfer of transuranic (TRU) waste between the Materials and Fuels Complex (MFC) and the Advanced Mixed Waste Treatment Project (AMWTP). The information collected includes documentation that addresses the requirements for AMWTP and the applicable portion of their Resource Conservation and Recovery Act permits for receipt and treatment of TRU debris waste in AMWTP. This report has been prepared for contact-handled TRU debris waste generated by the Idaho National Laboratory at MFC. The TRU debris waste will be shipped to AMWTP for purposes of supercompaction. This Process Knowledge Summary Report includes information regarding, but not limited to, the generation process, the physical form, radiological characteristics, and chemical contaminants of the TRU debris waste, prohibited items, and packaging configuration. This report, along with the referenced supporting documents, will create a defensible and auditable record for waste originating from MFC.

  5. Effect of repeated contact on adhesion measurements involving polydimethylsiloxane structural material

    International Nuclear Information System (INIS)

    Kroner, E; Arzt, E; Maboudian, R

    2009-01-01

    During the last few years several research groups have focused on the fabrication of artificial gecko inspired adhesives. For mimicking these structures, different polymers are used as structure material, such as polydimethylsiloxanes (PDMS), polyurethanes (PU), and polypropylene (PP). While these polymers can be structured easily and used for artificial adhesion systems, the effects of repeated adhesion testing have never been investigated closely. In this paper we report on the effect of repeated adhesion measurements on the commercially available poly(dimethylsiloxane) polymer kit Sylgard 184 (Dow Corning). We show that the adhesion force decreases as a function of contact cycles. The rate of change and the final value of adhesion are found to depend on the details of the PDMS synthesis and structuring.

  6. INDUCTION OF ENZYME COCKTAILS BY LOW COST CARBON SOURCES FOR PRODUCTION OF MONOSACCHARIDE-RICH SYRUPS FROM PLANT MATERIALS

    Directory of Open Access Journals (Sweden)

    Caroline T. Gilleran

    2010-05-01

    Full Text Available The production of cellulases, hemicellulases, and starch-degrading enzymes by the thermophilic aerobic fungus Talaromyces emersonii under liquid state culture on various food wastes was investigated. A comprehensive enzyme screening was conducted, which resulted in the identification of spent tea leaves as a potential substrate for hydrolytic enzyme production. The potent, polysaccharide-degrading enzyme-rich cocktail produced when tea leaves were utilised as sole carbon source was analysed at a protein and mRNA level and shown to exhibit high level production of key cellulose and hemicellulose degrading enzymes. As presented in this paper, the crude enzyme preparation produced after 120 h growth of Talaromyces emersonii on used tea leaves is capable of hydrolysing other lignocellulosic materials into their component monosaccharides, generating high value sugar syrups with a host of industrial applications including conversion to fuels and chemicals.

  7. Influence of fine grinding on the hydrolysis of cellulosic materials - acid vs enzymic

    Energy Technology Data Exchange (ETDEWEB)

    Millet, M A; Effland, M J; Caulfield, D F

    1979-01-01

    The effect of vibratory milling on the enzymic and dilute H/sub 2/SO/sub 4/ hydrolysis of cotton linters, newsprint, Douglas fir, and red oak was investigated by determining the rate and degree of hydrolysis, maximum yield of reducing sugars, and cellulose crystallinity index. Linters were totally hydrolyzed in 10 days after 60 min milling; oak carbohydrates were 93% convertible to sugar in the same period after 240 min milling. Vibratory milling substantially increased the rates of acid hydrolysis of all 4 substrates, nearly 9- and 5-fold for linters and other lignocellulosic materials, respectively. Increases in maximum sugar yields under batch conditions were 60 to 140% higher than those for unmilled materials.

  8. Enzymes for Degradation of Energetic Materials and Demilitarization of Explosives Stockpiles - SERDP Annual (Interim) Report, 12/98

    Energy Technology Data Exchange (ETDEWEB)

    Shah, M.M.

    1999-01-18

    The current stockpile of energetic materials requiring disposal contains about half a million tons. Through 2001, over 2.1 million tons are expected to pass through the stockpile for disposal. Safe and environmentally acceptable methods for disposing of these materials are needed. This project is developing safe, economical, and environmentally sound processes using biocatalyst (enzymes) to degrade energetic materials and to convert them into economically valuable products. Alternative methods for destroying these materials are hazardous, environmentally unacceptable, and expensive. These methods include burning, detonation, land and sea burial, treatment at high temperature and pressure, and treatment with harsh chemicals. Enzyme treatment operates at room temperature and atmospheric pressure in a water solution.

  9. Protein deposition on a lathe-cut silicone hydrogel contact lens material.

    Science.gov (United States)

    Subbaraman, Lakshman N; Woods, Jill; Teichroeb, Jonathan H; Jones, Lyndon

    2009-03-01

    To determine the quantity of total protein, total lysozyme, and the conformational state of lysozyme deposited on a novel, lathe-cut silicone hydrogel (SiHy) contact lens material (sifilcon A) after 3 months of wear. Twenty-four subjects completed a prospective, bilateral, daily-wear, 9-month clinical evaluation in which the subjects were fitted with a novel, custom-made, lathe-cut SiHy lens material. The lenses were worn for three consecutive 3-month periods, with lenses being replaced after each period of wear. After 3 months of wear, the lenses from the left eye were collected and assessed for protein analysis. The total protein deposited on the lenses was determined by a modified Bradford assay, total lysozyme using Western blotting and the lysozyme activity was determined using a modified micrococcal assay. The total protein recovered from the custom-made lenses was 5.3 +/- 2.3 microg/lens and the total lysozyme was 2.4 +/- 1.2 microg/lens. The denatured lysozyme found on the lenses was 1.9 +/- 1.0 microg/lens and the percentage of lysozyme denatured was 80 +/- 10%. Even after 3 months of wear, the quantity of protein and the conformational state of lysozyme deposited on these novel lens materials was very similar to that found on similar surface-coated SiHy lenses after 2 to 4 weeks of wear. These results indicate that extended use of the sifilcon A material is not deleterious in terms of the quantity and quality of protein deposited on the lens.

  10. Original Article Effect of Soft Contact Lens Materials on Tear Film ...

    African Journals Online (AJOL)

    problems, results in intolerance of contact lens wear and damage (Foulks, ... reported that contact lens-related dry eye may be ... eliminating or modifying the refractive error ..... risk of eye infection, easier handling due to ... Adv Exp Med Biol.

  11. Boundary element method for normal non-adhesive and adhesive contacts of power-law graded elastic materials

    Science.gov (United States)

    Li, Qiang; Popov, Valentin L.

    2018-03-01

    Recently proposed formulation of the boundary element method for adhesive contacts has been generalized for contacts of power-law graded materials with and without adhesion. Proceeding from the fundamental solution for single force acting on the surface of an elastic half space, first the influence matrix is obtained for a rectangular grid. The inverse problem for the calculation of required stress in the contact area from a known surface displacement is solved using the conjugate-gradient technique. For the transformation between the stresses and displacements, the Fast Fourier Transformation is used. For the adhesive contact of graded material, the detachment criterion based on the energy balance is proposed. The method is validated by comparison with known exact analytical solutions as well as by proving the independence of the mesh size and the grid orientation.

  12. Bio-Inspiered Blood-Contacting Materials Elaborated For The Heart Assist System

    Directory of Open Access Journals (Sweden)

    Major R.

    2015-09-01

    Full Text Available The paper presents the main achievements of the author on the development of blood contacting materials. The main objective of the work is to elaborate materials dedicated for the heart support systems. Appropriately designed biomaterial surfaces enable fully controlled cellular differentiation, proliferation, and even restoration of the tissue structure on solids. The paper presents two approaches to modify the surface, which can control the life processes of tissue. The first solution considers the topography in the form of cell niches. The main objective of the study is a modified surface of thin films deposited on the polymer substrate constituting the microenvironment for the cells caused by residual stress and optimized stiffness of the surface using the plasma methods. The research hypothesis was the plasma surface modification method generating a controlled contribution of residual stress in the coating affect the surface topography in the form of nano- wrinkles similar to the niches in the tissue environment. Topography and stiffness of the surface coating allows the targeted cellular differentiation. The properly formed surface topography effectively inhibits blood clotting processes. The second solution considers implementation of self-organizing feature of extracellular matrix like coatings and selective cell mobilization. The multiscale analysis and phenomenologic description were performed to experimental research. For this purpose, the deposition method was based on electrostatic interactions in polyelectrolytes. This type of cell-polymer structure imitate the native structures.

  13. Irradiation of structural materials in contact with lead bismuth eutectic in the high flux reactor

    Energy Technology Data Exchange (ETDEWEB)

    Magielsen, A.J., E-mail: magielsen@nrg.eu [Nuclear Research and Consultancy Group, Westerduinweg 3, Postbus 25, 1755 ZG Petten (Netherlands); Jong, M.; Bakker, T.; Luzginova, N.V.; Mutnuru, R.K.; Ketema, D.J.; Fedorov, A.V. [Nuclear Research and Consultancy Group, Westerduinweg 3, Postbus 25, 1755 ZG Petten (Netherlands)

    2011-08-31

    In the framework of the materials domain DEMETRA in the European Transmutation research and development project EUROTRANS, irradiation experiment IBIS has been performed in the High Flux Reactor in Petten. The objective was to investigate the synergystic effects of irradiation and lead bismuth eutectic exposure on the mechanical properties of structural materials and welds. In this experiment ferritic martensitic 9 Cr steel, austenitic 316L stainless steel and their welds have been irradiated for 250 Full Power Days up to a dose level of 2 dpa. Irradiation temperatures have been kept constant at 300 deg. C and 500 deg. C. During the post-irradiation test phase, tensile tests performed on the specimens irradiated at 300 deg. C have shown that the irradiation hardening of ferritic martensitic 9 Cr steel at 1.3 dpa is 254 MPa, which is in line with the irradiation hardening obtained for ferritic martensitic Eurofer97 steel investigated in the fusion program. This result indicates that no LBE interaction at this irradiation temperature is present. A visual inspection is performed on the specimens irradiated in contact with LBE at 500 deg. C and have shown blackening on the surface of the specimens and remains of LBE that makes a special cleaning procedure necessary before post-irradiation mechanical testing.

  14. Contact Mechanics and Failure Modes of Compliant Polymeric Bearing Materials for Knee Cartilage Replacement

    Science.gov (United States)

    Tohfafarosh, Mariya Shabbir

    control samples. However, chemical spectra of electron beam sterilized samples revealed minor changes, which were absent in unsterilized and gamma sterilized samples. Upon successful sterilization evaluation, both polycarbonate urethane and the novel hydrogel were investigated for the contact mechanics of compliant-on-compliant artificial knee bearings using a finite element analysis approach. A simplified, axisymmetric, finite element model of a medial knee compartment was developed and validated, and a design of simulation experiments was carried out to evaluate the effect of implant conformity, implant thickness and material properties on the contact mechanics of compliant knee bearings under normal walking and stair climbing loads. All input parameters, namely, implant conformity, implant thickness and material properties, significantly (pengineering strain (39 - 53% true strain) without any signs of cracking or fracture. The tension was determined to be the primary failure mode for the proposed materials, and the tensile test was used to define the failure criteria of the materials. The unconfined compression tests were used to define the yield stresses and strains under compression, which is the main mode of loading for the knee joint. The results of the plane strain compression were modeled using a finite element model and the maximum principal stress, von Mises stress, maximum shear stress, and maximum principal strain failure criteria were predicted at the corresponding yield strain of each material formulation. Upon comparing the knee model contact stress and strain prediction under normal walking and stair climbing loads with those of the empirical failure criteria at yield, the polycarbonate urethane showed better overall potential for use in compliant knee implants, while the hydrogels exhibited higher potential for delamination or fracture, especially if appropriate implant conformity and thickness are not employed. The outcome of this study and the previous

  15. Assessment of the Brazilian potential for the production of enzymes for biofuels from agroindustrial materials

    Energy Technology Data Exchange (ETDEWEB)

    Machado de Castro, Silvia [Federal University of Rio de Janeiro, Environmental Engineering Program, Rio de Janeiro (Brazil); Machado de Castro, Aline [PETROBRAS, Biotechnology Division, Research and Development Center, Rio de Janeiro (Brazil)

    2012-03-15

    Brazil is one of the largest bioethanol and biodiesel producers in the world. Its biodiversity and environmental characteristics create the opportunity to make Brazil a major producer of biotechnological products, such as enzymes for the bioenergy industry. This review gives a brief status of the production of amylases, cellulases, xylanases, and lipases and their application on the synthesis of bioethanol and biodiesel. The historical utilization of several agroindustrial by-products as feedstocks in such processes are presented, as well as the Brazilian market for these enzymes. Finally, an innovative and multidisciplinary approach based on geographic information systems is used in a case study for the estimation of the potential production of the biocatalysts in Brazil. Results indicate that the national production of concentrated preparations based on amylases, cellulases, lipases, and xylanases could reach 3.1 x 10{sup 7}, 3.2 x 10{sup 7}, 3.1 x 10{sup 8}, and 2.9 x 10{sup 9} t, respectively. Therefore, Brazil presents a huge potential for the production of biocatalysts from renewable materials. (orig.)

  16. Comparison of the Contact stress and friction behavior of SiC and ZrO2 materials

    International Nuclear Information System (INIS)

    Lindberg, L.J.; Richerson, D.W.

    1985-01-01

    Studies were performed to further elucidate the friction and contact- stress characteristics of structural ceramic materials. New data for fully stabilized and partially stabilized zirconia ceramics are compared with prior test results for sintered SiC. The comparison provides further evidence that the high temperature friction characteristics of sinstered SiC are strongly influenced by the presence of a viscous surface layer. The results also show that a ceramic material with lower coefficient of friction and higher fracture toughness has increased resistance to strength-reducing surface damage due to contact stress

  17. Suitability of polystyrene as a functional barrier layer in coloured food contact materials.

    Science.gov (United States)

    Genualdi, Susan; Addo Ntim, Susana; Begley, Timothy

    2015-01-01

    Functional barriers in food contact materials (FCMs) are used to prevent or reduce migration from inner layers in multilayer structures to food. The effectiveness of functional barrier layers was investigated in coloured polystyrene (PS) bowls due to their intended condition of use with hot liquids such as soups or stew. Migration experiments were performed over a 10-day period using USFDA-recommended food simulants (10% ethanol, 50% ethanol, corn oil and Miglyol) along with several other food oils. At the end of the 10 days, solvent dyes had migrated from the PS bowls at 12, 1 and 31,000 ng cm(-)(2) into coconut oil, palm kernel oil and Miglyol respectively, and in coconut oil and Miglyol the colour change was visible to the human eye. Scanning electron microscope (SEM) images revealed that the functional barrier was no longer intact for the bowls exposed to coconut oil, palm kernel oil, Miglyol, 10% ethanol, 50% ethanol and goat's milk. Additional tests showed that 1-dodecanol, a lauryl alcohol derived from palm kernel oil and coconut oil, was present in the PS bowls at an average concentration of 11 mg kg(-1). This compound is likely to have been used as a dispersing agent for the solvent dye and aided the migration of the solvent dye from the PS bowl into the food simulant. The solvent dye was not found in the 10% ethanol, 50% ethanol and goat's milk food simulants above their respective limits of detection, which is likely to be due to its insolubility in aqueous solutions. A disrupted barrier layer is of concern because if there are unregulated materials in the inner layers of the laminate, they may migrate to food, and therefore be considered unapproved food additives resulting in the food being deemed adulterated under the Federal Food Drug and Cosmetic Act.

  18. Printed paper and board food contact materials as a potential source of food contamination.

    Science.gov (United States)

    Van Bossuyt, Melissa; Van Hoeck, Els; Vanhaecke, Tamara; Rogiers, Vera; Mertens, Birgit

    2016-11-01

    Food contact materials (FCM) are estimated to be the largest source of food contamination. Apart from plastics, the most commonly used FCM are made of printed paper and board. Unlike their plastic counterparts, these are not covered by a specific European regulation. Several contamination issues have raised concerns towards potential adverse health effects caused by exposure to substances migrating from printed paper and board FCM. In the current study, an inventory combining the substances which may be used in printed paper and board FCM, was created. More than 6000 unique compounds were identified, the majority (77%) considered non-evaluated in terms of potential toxicity. Based on a preliminary study of their physicochemical properties, it is estimated that most of the non-evaluated single substances have the potential to migrate into the food and become bioavailable after oral intake. Almost all are included in the FACET tool, indicating that their use in primary food packaging has been confirmed by industry. Importantly, 19 substances are also present in one of the lists with substances of concern compiled by the European Chemicals Agency (ECHA). To ensure consumer safety, the actual use of these substances in printed paper and board FCM should be investigated urgently. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Characterisation and potential migration of silver nanoparticles from commercially available polymeric food contact materials.

    Science.gov (United States)

    Addo Ntim, Susana; Thomas, Treye A; Begley, Timothy H; Noonan, Gregory O

    2015-01-01

    The potential for consumer exposure to nano-components in food contact materials (FCMs) is dependent on the migration of nanomaterials into food. Therefore, characterising the physico-chemical properties and potential for migration of constituents is an important step in assessing the safety of FCMs. A number of commercially available food storage products, purchased domestically within the United States and internationally, that claim to contain nanosilver were evaluated. The products were made of polyethylene, polypropylene and polyphenylene ether sulfone and all contained silver (0.001-36 mg kg(-1) of polymer). Silver migration was measured under various conditions, including using 3% acetic acid and water as food simulants. Low concentrations (sub-ppb levels) of silver were detected in the migration studies generally following a trend characterised by a surface desorption phenomenon, where the majority of the silver migration occurred in the first of three consecutive exposures. Silver nanoparticles were not detected in food simulants, suggesting that the silver migration may be due solely to ionic silver released into solution from oxidation of the silver nanoparticle surface. The absence of detectable silver nanoparticles was consistent with expectations from a physico-chemical view point. For the products tested, current USFDA guidance for evaluating migration from FCMs was applicable.

  20. The contact heat transfer between the heating plate and granular materials in rotary heat exchanger under overloaded condition

    Directory of Open Access Journals (Sweden)

    Luanfang Duan

    2018-03-01

    Full Text Available In the present work, the contact heat transfer between the granular materials and heating plates inside plate rotary heat exchanger (PRHE was investigated. The heat transfer coefficient is dominated by the contact heat transfer coefficient at hot wall surface of the heating plates and the heat penetration inside the solid bed. A plot scale PRHE with a diameter of Do = 273 mm and a length of L = 1000 mm has been established. Quartz sand with dp = 2 mm was employed as the experimental material. The operational parameters were in the range of ω = 1 – 8 rpm, and F = 15, 20, 25, 30%, and the effect of these parameters on the time-average contact heat transfer coefficient was analyzed. The time-average contact heat transfer coefficient increases with the increase of rotary speed, but decreases with the increase of the filling degree. The measured data of time-average heat transfer coefficients were compared with theoretical calculations from Schlünder’s model, a good agreement between the measurements and the model could be achieved, especially at a lower rotary speed and filling degree level. The maximum deviation between the calculated data and the experimental data is approximate 10%. Keywords: Rotary heat exchanger, Contact heat transfer, Granular material, Heating plate, Overloaded

  1. Order of 12 August 1986 on treatment by ionizing radiation of material and objects in contact with foods and beverages

    International Nuclear Information System (INIS)

    1986-01-01

    This Order applies to packaging material and articles in contact with foods and beverages, when they are treated by cobalt 60 or caesium 137 gamma rays, accelerated electrons of the energy lower than or equal to 10 MeV and X rays of the energy lower than or equal to 10 MeV. (NEA) [fr

  2. A novel safety assessment strategy for non-intentionally added substances (NIAS) in carton food contact materials

    NARCIS (Netherlands)

    Koster, S.; Rennen, M.; Leeman, W.; Houben, G.; Muilwijk, B.; Acker, F. van; Krul, L.

    2014-01-01

    One of the main challenges in food contact materials research is to prove that the presence of non-intentionally added substances (NIAS) is not a safety issue. Migration extracts may contain many unknown substances present at low concentrations. It is difficult and time-consuming to identify all

  3. DEVELOPING OF INSTRUCTIONAL MEDIA-BASED ANIMATION VIDEO ON ENZYME AND METABOLISM MATERIAL IN SENIOR HIGH SCHOOL

    Directory of Open Access Journals (Sweden)

    Muhammad Mustofa Yusuf

    2017-11-01

    Full Text Available The research aimed to product a learning material related to animation video on enzyme and metabolism material for high school student which is validated by media and material experts, educational practition and student legibility. Research and development model is ADDIE with quantitative-qualitative data analyzing methode. Data collection was obtained from validation results by media and material experts, educational partition and student legibility. The validation results were scores and suggestion. The percentage of product from expert media validation (100%, expert material validation (89,58%, educational practition (84,61%, and student legibility (81,91% showed valid of the criteria and feasible to use after revision.

  4. Corneal cell adhesion to contact lens hydrogel materials enhanced via tear film protein deposition.

    Directory of Open Access Journals (Sweden)

    Claire M Elkins

    Full Text Available Tear film protein deposition on contact lens hydrogels has been well characterized from the perspective of bacterial adhesion and viability. However, the effect of protein deposition on lens interactions with the corneal epithelium remains largely unexplored. The current study employs a live cell rheometer to quantify human corneal epithelial cell adhesion to soft contact lenses fouled with the tear film protein lysozyme. PureVision balafilcon A and AirOptix lotrafilcon B lenses were soaked for five days in either phosphate buffered saline (PBS, borate buffered saline (BBS, or Sensitive Eyes Plus Saline Solution (Sensitive Eyes, either pure or in the presence of lysozyme. Treated contact lenses were then contacted to a live monolayer of corneal epithelial cells for two hours, after which the contact lens was sheared laterally. The apparent cell monolayer relaxation modulus was then used to quantify the extent of cell adhesion to the contact lens surface. For both lens types, lysozyme increased corneal cell adhesion to the contact lens, with the apparent cell monolayer relaxation modulus increasing up to an order of magnitude in the presence of protein. The magnitude of this increase depended on the identity of the soaking solution: lenses soaked in borate-buffered solutions (BBS, Sensitive Eyes exhibited a much greater increase in cell attachment upon protein addition than those soaked in PBS. Significantly, all measurements were conducted while subjecting the cells to moderate surface pressures and shear rates, similar to those experienced by corneal cells in vivo.

  5. Frictional contact problems for electro-viscoelastic materials with long-term memory, damage, and adhesion

    Directory of Open Access Journals (Sweden)

    Tedjani Hadj Ammar

    2014-10-01

    Full Text Available We consider a quasistatic contact problem between two electro-viscoelastic bodies with long-term memory and damage. The contact is frictional and is modelled with a version of normal compliance condition and the associated Coulomb's law of friction in which the adhesion of contact surfaces is taken into account. We derive a variational formulation for the model and prove an existence and uniqueness result of the weak solution. The proof is based on arguments of evolutionary variational inequalities, a classical existence and uniqueness result on parabolic inequalities, and Banach fixed point theorem.

  6. The effects of the modulus of the lens material on intraocular pressure measurement through soft contact lenses.

    Science.gov (United States)

    Boyraz, S; Güngör, I

    2013-09-01

    To investigate the effects of the modulus of the lens material on the intraocular pressure measurement using the Tono-Pen XL applanation tonometer through soft contact lenses. Thirty eyes of 15 patients with myopia were evaluated. Intraocular pressure (IOP) measurements were performed using Tono-Pen XL directly over cornea, and subsequently through three soft contact lenses made up of different lens materials. All were -3.00 diopter soft contact lenses: lotrafilcon A with a low water content (24%) and high modulus (1.4 MPa) (CL-I), balafilcon A with a moderate water content (36%) and moderate modulus (1.1 MPa) (CL-II), and vifilcon A with a moderate water content (55%) and low modulus (0.79 MPa) (CL-III). IOP measurements through contact lenses were compared with each other, and with direct corneal measurements. The mean age of the patients (11 males and 4 females) was 26.86±5.62 years. All measurements obtained through CLs were significantly higher than the direct corneal measurements. The measurements through CLs differed by 4.61±0.54 mmHg (P=0,001), 2.9±0.46 mmHg (P=0.001), and 1.94±0.51 mmHg (P=0,003) for CL-I, CL-II and CL-III, respectively. In the paired comparisons of measurements through CLs, all comparisons were significant except the comparison of measurements through CL-II and CL-III (P=0.128). IOP measurements through silicone-hydrogel contact lenses with a high modulus and low water content were higher compared to the other contact lenses. While measuring IOP through CLs, the clinicians should consider the effect of the lens material and the features of the device used.

  7. The fabrication of carbon nanotube field-effect transistors with semiconductors as the source and drain contact materials.

    Science.gov (United States)

    Xiao, Z; Camino, F E

    2009-04-01

    Sb(2)Te(3) and Bi(2)Te(2)Se semiconductor materials were used as the source and drain contact materials in the fabrication of carbon nanotube field-effect transistors (CNTFETs). Ultra-purified single-walled carbon nanotubes (SWCNTs) were ultrasonically dispersed in N-methyl pyrrolidone solvent. Dielectrophoresis was used to deposit and align SWCNTs for fabrication of CNTFETs. The Sb(2)Te(3)- and Bi(2)Te(2)Se-based CNTFETs demonstrate p-type metal-oxide-silicon-like I-V curves with high on/off drain-source current ratio at large drain-source voltages and good saturation of drain-source current with increasing drain-source voltage. The fabrication process developed is novel and has general meaning, and could be used for the fabrication of SWCNT-based integrated devices and systems with semiconductor contact materials.

  8. Plasticizers used in food-contact materials affect adipogenesis in 3T3-L1 cells.

    Science.gov (United States)

    Pomatto, Valentina; Cottone, Erika; Cocci, Paolo; Mozzicafreddo, Matteo; Mosconi, Gilberto; Nelson, Erik Russel; Palermo, Francesco Alessandro; Bovolin, Patrizia

    2018-04-01

    Recent studies suggest that exposure to some plasticizers, such as Bisphenol A (BPA), play a role in endocrine/metabolic dispruption and can affect lipid accumulation in adipocytes. Here, we investigated the adipogenic activity and nuclear receptor interactions of four plasticizers approved for the manufacturing of food-contact materials (FCMs) and currently considered safer alternatives. Differentiating 3T3-L1 mouse preadipocytes were exposed to scalar concentrations (0.01-25 μM) of DiNP (Di-iso-nonyl-phthalate), DiDP (Di-iso-decyl-phthalate), DEGDB (Diethylene glycol dibenzoate), or TMCP (Tri-m-cresyl phosphate). Rosiglitazone, a well-known pro-adipogenic peroxisome proliferator activated receptor gamma (PPARγ) agonist, and the plasticizer BPA were included as reference compounds. All concentrations of plasticizers were able to enhance lipid accumulation, with TMCP being the most effective one. Accordingly, when comparing in silico the ligand binding efficiencies to the nuclear receptors PPARγ and retinoid-X-receptor-alpha (RXRα), TMPC displayed the highest affinity to both receptors. Differently from BPA, the four plasticizers were most effective in enhancing lipid accumulation when added in the mid-late phase of differentiation, thus suggesting the involvement of different intracellular signalling pathways. In line with this, TMCP, DiDP, DiNP and DEGDB were able to activate PPARγ in transient transfection assays, while previous studies demonstrated that BPA acts mainly through other nuclear receptors. qRT-PCR studies showed that all plasticizers were able to increase the expression of CCAAT/enhancer binding protein β (Cebpβ) in the early steps of adipogenesis, and the adipogenesis master gene Pparγ2 in the middle phase, with very similar efficacy to that of Rosiglitazone. In addition, TMCP was able to modulate the expression of both Fatty Acid Binding Protein 4/Adipocyte Protein 2 (Fabp4/Ap2) and Lipoprotein Lipase (Lpl) transcripts in the late phase

  9. 21 CFR 173.357 - Materials used as fixing agents in the immobilization of enzyme preparations.

    Science.gov (United States)

    2010-04-01

    ... glucose isomerase enzyme preparations for use in the manufacture of high fructose corn syrup, in... manufacture of high fructose corn syrup, in accordance with § 184.1372 of this chapter. Cellulose triacetate... enzyme preparations for use in the manufacture of high fructose corn syrup, in accordance with § 184.1372...

  10. Pectin-modifying enzymes and pectin-derived materials: applications and impacts.

    Science.gov (United States)

    Bonnin, Estelle; Garnier, Catherine; Ralet, Marie-Christine

    2014-01-01

    Pectins are complex branched polysaccharides present in primary cell walls. As a distinctive feature, they contain high amount of partly methyl-esterified galacturonic acid and low amount of rhamnose and carry arabinose and galactose as major neutral sugars. Due to their structural complexity, they are modifiable by many different enzymes, including hydrolases, lyases, and esterases. Their peculiar structure is the origin of their physicochemical properties. Among others, their remarkable gelling properties make them a key additive for food industries. Pectin-degrading enzymes and -modifying enzymes may be used in a wide variety of applications to modulate pectin properties or produce pectin derivatives and oligosaccharides with functional as well as nutritional interests. This paper reviews the scientific information available on pectin structure, pectin-modifying enzymes, and the use of enzymes to produce pectin with controlled structure or pectin-derived oligosaccharides, with functional or nutritional interesting properties.

  11. Current flow in a 3-terminal thin film contact with dissimilar materials and general geometric aspect ratios

    International Nuclear Information System (INIS)

    Zhang Peng; Hung, Derek M H; Lau, Y Y

    2013-01-01

    The current flow pattern, together with the contact resistance, is calculated analytically in a Cartesian 3-terminal thin film contact with dissimilar materials. The resistivities and the geometric dimensions in the individual contact members, as well as the terminal voltages, may assume arbitrary values. We show that the current flow patterns and the contact resistance may be conveniently decomposed into the even and odd solution. The even solution gives exclusively and totally the current flowing from the source to the gate. The odd solution gives exclusively and totally the current flowing from the source to the drain. Current crowding at the edges, and current partition in different regions are displayed. The analytic solutions are validated using a simulation code. The bounds on the variation of the contact resistance are given. This paper may be considered as the generalization of the transmission line model and the Kennedy-Murley model that were used extensively in the characterization of thin-film devices. For completeness, we include the general results for the cylindrical geometry, which are qualitatively similar to the even solution of the Cartesian geometry.

  12. In vitro evaluation of resonance frequency analysis values to different implant contact ratio and stiffness of surrounding material.

    Science.gov (United States)

    Kwak, Mu-Seung; Kim, Seok-Gyu

    2013-11-01

    The present study was aimed to evaluate the influence of implant contact ratio and stiffness of implant-surrounding materials on the resonance frequency analysis (RFA) values. Seventy resin blocks that had the different amounts (100, 50, 30, 15%) of resin-implant contact (RIC) were fabricated. Ten silicone putty blocks with 100% silicone-implant contact were also made. The implants with Ø5.0 mm × 13.0 mm were placed on eighty specimen blocks. The RFA value was measured on the transducer that was connected to each implant by Osstell Mentor. Kruskal-Wallis and Scheffe's tests (α=.05) were done for statistical analysis. The control resin group with 100% RIC had the highest RFA value of 83.9, which was significantly different only from the resin group with 15% RIC among the resin groups. The silicone putty group with 100% contact had the lowest RFA value of 36.6 and showed statistically significant differences from the resin groups. Within the limitations of this in vitro study, there was no significant difference in the RFA values among the resin groups with different RIC's except when the RIC difference was more than 85%. A significant increase in the RFA value was observed related to the increase in stiffness of material around implant.

  13. The Quantified Characterization Method of the Micro-Macro Contacts of Three-Dimensional Granular Materials on the Basis of Graph Theory.

    Science.gov (United States)

    Guan, Yanpeng; Wang, Enzhi; Liu, Xiaoli; Wang, Sijing; Luan, Hebing

    2017-08-03

    We have attempted a multiscale and quantified characterization method of the contact in three-dimensional granular material made of spherical particles, particularly in cemented granular material. Particle contact is defined as a type of surface contact with voids in its surroundings, rather than a point contact. Macro contact is a particle contact set satisfying the restrictive condition of a two-dimensional manifold with a boundary. On the basis of graph theory, two dual geometrical systems are abstracted from the granular pack. The face and the face set, which satisfies the two-dimensional manifold with a boundary in the solid cell system, are extracted to characterize the particle contact and the macro contact, respectively. This characterization method is utilized to improve the post-processing in DEM (Discrete Element Method) from a micro perspective to describe the macro effect of the cemented granular material made of spherical particles. Since the crack has the same shape as its corresponding contact, this method is adopted to characterize the crack and realize its visualization. The integral failure route of the sample can be determined by a graph theory algorithm. The contact force is assigned to the weight value of the face characterizing the particle contact. Since the force vectors can be added, the macro contact force can be solved by adding the weight of its corresponding faces.

  14. Solvability of Static Contact Problems with Coulomb Friction for Orthotropic Material

    Czech Academy of Sciences Publication Activity Database

    Eck, C.; Jarušek, Jiří

    2008-01-01

    Roč. 93, č. 1 (2008), s. 93-104 ISSN 0374-3535 R&D Projects: GA AV ČR IAA1075402 Institutional research plan: CEZ:AV0Z10190503 Keywords : contact problem * Coulomb friction * orthotropic elasticity Subject RIV: BA - General Mathematics Impact factor: 1.277, year: 2008

  15. Survey of the occurrence of 2,5-Di-tert-butylhydroquinone in food contact materials

    DEFF Research Database (Denmark)

    intended for the consumers identified in the initial survey under the Danish EPA’s LOUS-review (Environmental Project no. 1477). Based on literature search, contact to producers, importers and branches, the use of DTBHQ in these product categories evaluated to be scarce, with only one cosmetic product...

  16. Design, materials and R and D issues of innovative thermal contact joints for high heat flux applications

    International Nuclear Information System (INIS)

    Federici, G.; Haines, J.; Tillack, M.S.; Ulrickson, M.

    1995-01-01

    Plasma facing components in fusion machines are designed with a layer of sacrificial armour material facing the plasma and a high-conductivity material in contact with the coolant. One of the most critical issues associated with making the proposed design concept work, from a power handling point of view, is achieving the necessary contact conductance between the armour and the heat sink.This paper presents a novel idea for the interface joint between the sacrificial armour and the actively cooled permanent heat sink. It consists of a thermal bond layer of a binary or more complex alloy, treated in the semi-solid region in such a way as to lead to a fine dispersion of a globular solid phase into a liquid matrix (rheocast process). The alloy in this ''mushy state'' exhibits a time-dependent, shear rate-dependent viscosity, which is maintained reversibly when the material is solidified and heated again in the semi-solid state. The function of the thermal bond layer is to facilitate heat transfer between the replaceable armour and the permanent heat sink without building up excessive thermal stresses, as in conventional brazed joints, and allow an easy replacement whenever needed without disturbing the coolant system. No contact pressure is required in this case to provide the desired heat transfer conductance, and the reversible thixotropic properties of the rheocast material should guarantee the stability of the layer in the semi-solid conditions.Key design, material and testing issues are identified and discussed in this paper with emphasis on specific needs for future research and development work. Examples of suitable material options which are being considered are reported together with some initial heat transfer analysis results. (orig.)

  17. Sustained Ocular Delivery of Ciprofloxacin Using Nanospheres and Conventional Contact Lens Materials

    Science.gov (United States)

    Garhwal, Rahul; Shady, Sally F.; Ellis, Edward J.; Ellis, Jeanne Y.; Leahy, Charles D.; McCarthy, Stephen P.; Crawford, Kathryn S.

    2012-01-01

    Purpose. To formulate conventional contact lenses that incorporate nanosphere-encapsulated antibiotic and demonstrate that the lenses provide for sustained antibacterial activity. Methods. A copolymer composed of pullulan and polycaprolactone (PCL) was used to synthesize core-shell nanospheres that encapsulated ciprofloxacin. Bactericidal activity of the nanosphere-encapsulated ciprofloxacin (nanosphere/cipro) was tested by using liquid cultures of either Staphylococcus aureus or Pseudomonas aeruginosa. Nanosphere/cipro was then incorporated into HEMA-based contact lenses that were tested for growth inhibition of S. aureus or P. aeruginosa in liquid cultures inoculated daily with fresh bacteria. Lens designs included thin or thick lenses incorporating nanosphere/cipro and ciprofloxacin-HCl-soaked Acuvue lenses (Acuvue; Johnson & Johnson Vision Care, Inc., Jacksonville, FL). Results. Less than 2 μg/mL of nanosphere/cipro effectively inhibited the proliferation of cultures inoculated with 107 or 108 bacteria/mL of S. aureus and P. aeruginosa, respectively. HEMA-based contact lenses polymerized with nanosphere/cipro were transparent, effectively inhibited the proliferation of greater than 107/mL of bacteria added daily over 3 days of culture, and killed up to 5 × 109 total microbes in a single inoculation. A thicker lens design provided additional inhibition of bacterial growth for up to 96 hours. Conclusions. Core-shell nanospheres loaded with an antibiotic can be incorporated into a conventional, transparent contact lens and provide for sustained and effective bactericidal activity and thereby provide a new drug delivery platform for widespread use in treating ocular disorders. PMID:22266514

  18. Effects of contact resistance on electrical conductivity measurements of SiC-based materials

    Energy Technology Data Exchange (ETDEWEB)

    Youngblood, G.E.; Thomsen, E.C.; Henager, C.H., E-mail: chuck.henager@pnnl.gov

    2013-11-15

    A combination 2/4-probe method was used to measure electrical resistances across a pure, monolithic CVD-SiC disc sample with contact resistance at the SiC/metallic electrode interfaces. By comparison of the almost simultaneous 2/4-probe measurements, the specific contact resistance (R{sub c}) and its temperature dependence were determined for two types (sputtered gold and porous nickel) electrodes from room temperature (RT) to ∼973 K. The R{sub c}-values behaved similarly for each type of metallic electrode: R{sub c} > ∼1000 Ω cm{sup 2} at RT, decreasing continuously to ∼1–10 Ω cm{sup 2} at 973 K. The temperature dependence of the inverse R{sub c} indicated thermally activated electrical conduction across the SiC/metallic interface with an apparent activation energy of ∼0.3 eV. For the flow channel insert application in a fusion reactor blanket, contact resistance potentially could reduce the transverse electrical conductivity by about 50%.

  19. Evaluation of susceptibility of polymer and rubber materials intended into contact with drinking water on biofilm formation

    Science.gov (United States)

    Szczotko, Maciej; Stankiewicz, Agnieszka; Jamsheer-Bratkowska, Małgorzata

    Plumbing materials in water distribution networks and indoor installations are constantly evolving. The application of new, more economical solutions with plastic materials eliminates the corrosion problems, however, do not fully protect the consumer against secondary microbial contamination of water intended for human consumption caused by the presence of a biofilm on the inner surface of materials applied. National Institute of Public Health - National Institute of Hygiene conducts research aimed at a comprehensive assessment of this type of materials, resulting their further marketing authorization in Poland. Evaluation and comparison of polymer and rubber materials intended to contact with water for the susceptibility to biofilm formation. Plastic materials (polyethylene, polypropylene, polyvinyl chloride) and rubber compounds (EPDM, NBR), from different manufacturers were evaluated. The study was carried out on 37 samples, which were divided into groups according to the material of which they were made. The testing was conducted according to the method based on conditions of dynamic flow of tap water. The level of bioluminescence in swabs taken from the surface of the tested materials was investigated with a luminometer. Evaluation of plastic materials does not show major objections in terms of hygienic assessment. All materials met the evaluation criteria established for methodology used. In case of rubber compounds, a substantial part clearly exceeded the limit values, which resulted in their negative assessment and elimination of these materials from domestic market. High susceptibility to the formation of biofilm in the group of products made of rubber compounds has been demonstrated. Examined plastic materials, except for several cases, do not revealed susceptibility to biofilm formation, but application of plastics for distribution of water intended for human consumption does not fully protect water from secondary, microbiological contamination. Complete

  20. Hydrogenation of passivated contacts

    Energy Technology Data Exchange (ETDEWEB)

    Nemeth, William; Yuan, Hao-Chih; LaSalvia, Vincenzo; Stradins, Pauls; Page, Matthew R.

    2018-03-06

    Methods of hydrogenation of passivated contacts using materials having hydrogen impurities are provided. An example method includes applying, to a passivated contact, a layer of a material, the material containing hydrogen impurities. The method further includes subsequently annealing the material and subsequently removing the material from the passivated contact.

  1. Wide range local resistance imaging on fragile materials by conducting probe atomic force microscopy in intermittent contact mode

    Energy Technology Data Exchange (ETDEWEB)

    Vecchiola, Aymeric [Laboratoire de Génie électrique et électronique de Paris (GeePs), UMR 8507 CNRS-CentraleSupélec, Paris-Sud and UPMC Universities, 11 rue Joliot-Curie, Plateau de Moulon, 91192 Gif-sur-Yvette (France); Concept Scientific Instruments, ZA de Courtaboeuf, 2 rue de la Terre de Feu, 91940 Les Ulis (France); Unité Mixte de Physique CNRS-Thales UMR 137, 1 avenue Augustin Fresnel, 91767 Palaiseau (France); Chrétien, Pascal; Schneegans, Olivier; Mencaraglia, Denis; Houzé, Frédéric, E-mail: frederic.houze@geeps.centralesupelec.fr [Laboratoire de Génie électrique et électronique de Paris (GeePs), UMR 8507 CNRS-CentraleSupélec, Paris-Sud and UPMC Universities, 11 rue Joliot-Curie, Plateau de Moulon, 91192 Gif-sur-Yvette (France); Delprat, Sophie [Unité Mixte de Physique CNRS-Thales UMR 137, 1 avenue Augustin Fresnel, 91767 Palaiseau (France); UPMC, Université Paris 06, 4 place Jussieu, 75005 Paris (France); Bouzehouane, Karim; Seneor, Pierre; Mattana, Richard [Unité Mixte de Physique CNRS-Thales UMR 137, 1 avenue Augustin Fresnel, 91767 Palaiseau (France); Tatay, Sergio [Molecular Science Institute, University of Valencia, 46980 Paterna (Spain); Geffroy, Bernard [Lab. Physique des Interfaces et Couches minces (PICM), UMR 7647 CNRS-École polytechnique, 91128 Palaiseau (France); Lab. d' Innovation en Chimie des Surfaces et Nanosciences (LICSEN), NIMBE UMR 3685 CNRS-CEA Saclay, 91191 Gif-sur-Yvette (France); and others

    2016-06-13

    An imaging technique associating a slowly intermittent contact mode of atomic force microscopy (AFM) with a home-made multi-purpose resistance sensing device is presented. It aims at extending the widespread resistance measurements classically operated in contact mode AFM to broaden their application fields to soft materials (molecular electronics, biology) and fragile or weakly anchored nano-objects, for which nanoscale electrical characterization is highly demanded and often proves to be a challenging task in contact mode. Compared with the state of the art concerning less aggressive solutions for AFM electrical imaging, our technique brings a significantly wider range of resistance measurement (over 10 decades) without any manual switching, which is a major advantage for the characterization of materials with large on-sample resistance variations. After describing the basics of the set-up, we report on preliminary investigations focused on academic samples of self-assembled monolayers with various thicknesses as a demonstrator of the imaging capabilities of our instrument, from qualitative and semi-quantitative viewpoints. Then two application examples are presented, regarding an organic photovoltaic thin film and an array of individual vertical carbon nanotubes. Both attest the relevance of the technique for the control and optimization of technological processes.

  2. The role of type III secretion system and lens material on adhesion of Pseudomonas aeruginosa to contact lenses.

    Science.gov (United States)

    Shen, Elizabeth P; Tsay, Ruey-Yug; Chia, Jean-San; Wu, Semon; Lee, Jing-Wen; Hu, Fung-Rong

    2012-09-21

    To determine the distribution of invasive and cytotoxic genotypes among ocular isolates of P. aeruginosa and investigate the influence of the type III secretion system (T3SS) on adhesion to conventional, cosmetic, and silicone hydrogel contact lenses (CL). Clinical isolates from 2001 to 2010 were analyzed by multiplex PCR for exoS, exoU, and exoT genes. Bacterial adhesion to etafilcon, nelfilcon (gray colored), balafilcon, and galyfilcon CL with or without artificial tear fluid (ATF) incubation were compared. Surface characteristics were determined with scanning electron microscopy (SEM). Among 87 total isolates, 64 strains were from microbial keratitis cases. CL-related microbial keratitis (CLMK) isolates were mostly of the cytotoxic genotype (expressing exoU) (P = 0.002). No significant differences were found in bacterial adhesion to all types of CL between the genotypes under T3SS-inducing conditions. A trend for least bacterial adhesion of galyfilcon compared to the other CL was noted for both genotypes. Needle complex pscC mutants adhered less to all materials than the wild type (P bacteria adhering on CL surfaces. CLMK isolates were mostly of cytotoxic genotype. Different genotypes did not significantly differ in its adhesion to various CL. T3SS and other adhesins are involved in bacteria-contact lens adhesion through complex interactions. Contact lens materials may also play an important role in the adherence of both genotypes of P. aeruginosa.

  3. Scientific Opinion on the safety evaluation of the active substances, sodium carbonate peroxyhydrate coated with sodium carbonate and sodium silicate, bentonite, sodium chloride, sodium carbonate for use in active food contact materials

    OpenAIRE

    EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF)

    2013-01-01

    This scientific opinion of the Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids deals with the safety evaluation of the powder mixture of the active substances sodium carbonate peroxyhydrate coated with sodium carbonate and sodium silicate (FCM substance No 1009), bentonite (CAS No 1302-78-9, FCM No 393), sodium chloride (CAS No 7647-14-5, FCM No 985), sodium carbonate (CAS No 497-19-8, FCM No 1008) which are intended to be used as combined oxygen generator and carbon...

  4. Behaviour of electroinsulating polyethylene and polyvinil-chloride-based materials in the contact with nitrogen oxides

    International Nuclear Information System (INIS)

    Korolev, V.M.; Koroleva, G.N.; Il'yukhina, Ya.A.

    1987-01-01

    The compatibility of electric cable sheaths on polyethylene and polyvinylchloride base with nitrogen tetroxide has been studied. It is shown, that the cables with polyethylene sheaths are compatible with N 2 O 4 and can be used in the conditions of the contact with it within 5 hours. Polyvinylchloride is incompatible with nitrogen oxide and polyvinylchloride based cables can be used only with oxides concentraton don't exceeding 0,5 g/l. Under the effect of high concentrations before dismounting or conducting works after accidents, these cables need special treatment for eliminating impact sensitivity acquired in the conditions of contamination

  5. An effect-directed strategy for characterizing emerging chemicals in food contact materials made from paper and board

    DEFF Research Database (Denmark)

    Rosenmai, Anna Kjerstine; Bengtström, Linda; Taxvig, Camilla

    2017-01-01

    Food contact materials (FCM) are any type of item intended to come into contact with foods and thus represent a potential source for human exposure to chemicals. Regarding FCMs made of paper and board, information pertaining to their chemical constituents and the potential impacts on human health...... FCMs exhibited activities in at least one assay. As proof-of-principle, FCM samples obtained from a sandwich wrapper and a pizza box were carried through a complete step-by-step multi-tiered approach. The pizza box exhibited ER activity, likely caused by the presence of bisphenol A, dibutyl phthalate......, and benzylbutyl phthalate. The sandwich wrapper exhibited AR antagonism, likely caused by abietic acid and dehydroabietic acid. Migration studies confirmed that the active chemicals can transfer from FCMs to food simulants. In conclusion, we report an effect-directed strategy that can identify hazards posed...

  6. Transfer, attachment, and formation of biofilms by Escherichia coli O157:H7 on meat-contact surface materials.

    Science.gov (United States)

    Simpson Beauchamp, Catherine; Dourou, Dimitra; Geornaras, Ifigenia; Yoon, Yohan; Scanga, John A; Belk, Keith E; Smith, Gary C; Nychas, George-John E; Sofos, John N

    2012-06-01

    Studies examined the effects of meat-contact material types, inoculation substrate, presence of air at the liquid-solid surface interface during incubation, and incubation substrate on the attachment/transfer and subsequent biofilm formation by Escherichia coli O157:H7 on beef carcass fabrication surface materials. Materials studied as 2 × 5 cm coupons included stainless steel, acetal, polypropylene, and high-density polyethylene. A 6-strain rifampicin-resistant E. coli O157:H7 composite was used to inoculate (6 log CFU/mL, g, or cm²) tryptic soy broth (TSB), beef fat/lean tissue homogenate (FLH), conveyor belt-runoff fluids, ground beef, or beef fat. Coupons of each material were submerged (4 °C, 30 min) in the inoculated fluids or ground beef, or placed between 2 pieces of inoculated beef fat with pressure (20 kg) applied. Attachment/transfer of the pathogen was surface material and substrate dependent, although beef fat appeared to negate differences among surface materials. Beef fat was the most effective (P transfer and subsequent biofilm formation by E. coli O157:H7. The results highlight the importance of thoroughly cleaning soiled surfaces to remove all remnants of beef fat or other organic material that may harbor or protect microbial contaminants during otherwise lethal antimicrobial interventions. © 2012 Institute of Food Technologists®

  7. Microstructural and Material Quality Effects on Rolling Contact Fatigue of Highly Elastic Intermetallic NiTi Ball Bearings

    Science.gov (United States)

    Dellacorte, Christopher; Howard, S. Adam; Thomas, Fransua; Stanford, Malcolm K.

    2017-01-01

    Rolling element bearings made from highly-elastic intermetallic materials (HIM)s, such as 60NiTi, are under development for applications that require superior corrosion and shock resistance. Compared to steel, intermetallics have been shown to have much lower rolling contact fatigue (RCF) stress capability in simplified 3-ball on rod (ASTM STP 771) fatigue tests. In the 3-ball tests, poor material quality and microstructural flaws negatively affect fatigue life but such relationships have not been established for full-scale 60NiTi bearings. In this paper, 3-ball-on-rod fatigue behavior of two quality grades of 60NiTi are compared to the fatigue life of full-scale 50mm bore ball bearings made from the same materials. 60NiTi RCF rods with material or microstructural flaws suffered from infant mortality failures at all tested stress levels while high quality 60NiTi rods exhibited no failures at lower stress levels. Similarly, tests of full-scale bearings made from flawed materials exhibited early surface fatigue and through crack type failures while bearings made from high quality material did not fail even in long-term tests. Though the full-scale bearing test data is yet preliminary, the results suggest that the simplified RCF test is a good qualitative predictor of bearing performance. These results provide guidance for materials development and to establish minimum quality levels required for successful bearing operation and life.

  8. Non-Contact Measurement of Thermal Diffusivity in Ion-Implanted Nuclear Materials

    Science.gov (United States)

    Hofmann, F.; Mason, D. R.; Eliason, J. K.; Maznev, A. A.; Nelson, K. A.; Dudarev, S. L.

    2015-11-01

    Knowledge of mechanical and physical property evolution due to irradiation damage is essential for the development of future fission and fusion reactors. Ion-irradiation provides an excellent proxy for studying irradiation damage, allowing high damage doses without sample activation. Limited ion-penetration-depth means that only few-micron-thick damaged layers are produced. Substantial effort has been devoted to probing the mechanical properties of these thin implanted layers. Yet, whilst key to reactor design, their thermal transport properties remain largely unexplored due to a lack of suitable measurement techniques. Here we demonstrate non-contact thermal diffusivity measurements in ion-implanted tungsten for nuclear fusion armour. Alloying with transmutation elements and the interaction of retained gas with implantation-induced defects both lead to dramatic reductions in thermal diffusivity. These changes are well captured by our modelling approaches. Our observations have important implications for the design of future fusion power plants.

  9. Commonly used disinfectants fail to eradicate Salmonella enterica biofilms from food contact surface materials.

    Science.gov (United States)

    Corcoran, M; Morris, D; De Lappe, N; O'Connor, J; Lalor, P; Dockery, P; Cormican, M

    2014-02-01

    Salmonellosis is the second most common cause of food-borne illness worldwide. Contamination of surfaces in food processing environments may result in biofilm formation with a risk of food contamination. Effective decontamination of biofilm-contaminated surfaces is challenging. Using the CDC biofilm reactor, the activities of sodium hypochlorite, sodium hydroxide, and benzalkonium chloride were examined against an early (48-h) and relatively mature (168-h) Salmonella biofilm. All 3 agents result in reduction in viable counts of Salmonella; however, only sodium hydroxide resulted in eradication of the early biofilm. None of the agents achieved eradication of mature biofilm, even at the 90-min contact time. Studies of activity of chemical disinfection against biofilm should include assessment of activity against mature biofilm. The difficulty of eradication of established Salmonella biofilm serves to emphasize the priority of preventing access of Salmonella to postcook areas of food production facilities.

  10. Non-Contact Measurement of Thermal Diffusivity in Ion-Implanted Nuclear Materials

    International Nuclear Information System (INIS)

    Hofmann, F.; Mason, D. R.; Eliason, J. K.; Maznev, A. A.; Nelson, K. A.; Dudarev, S. L.

    2015-01-01

    Knowledge of mechanical and physical property evolution due to irradiation damage is essential for the development of future fission and fusion reactors. Ion-irradiation provides an excellent proxy for studying irradiation damage, allowing high damage doses without sample activation. Limited ion-penetration-depth means that only few-micron-thick damaged layers are produced. Substantial effort has been devoted to probing the mechanical properties of these thin implanted layers. Yet, whilst key to reactor design, their thermal transport properties remain largely unexplored due to a lack of suitable measurement techniques. Here we demonstrate non-contact thermal diffusivity measurements in ion-implanted tungsten for nuclear fusion armour. Alloying with transmutation elements and the interaction of retained gas with implantation-induced defects both lead to dramatic reductions in thermal diffusivity. These changes are well captured by our modelling approaches. Our observations have important implications for the design of future fusion power plants

  11. The Setting Time of Polyether Impression Materials after Contact with Conventional and Experimental Gingival Margin Displacement Agents.

    Science.gov (United States)

    Nowakowska, Danuta; Raszewski, Zbigniew; Ziętek, Marek; Saczko, Jolanta; Kulbacka, Julita; Więckiewicz, Włodzimierz

    2018-02-01

    The compatibility of chemical gingival margin displacement agents with polyether impression materials has not been determined. The aim of this study was to evaluate the setting time of polyether impression elastomers after contact with conventional and experimental gingival displacement agents. The study compared the setting time of two polyether impression materials: medium body (Impregum Penta Soft) and light body (Impregum Garant L DuoSoft) after contact with 10 gingival displacement agents, including 5 conventional astringents (10%, 20%, and 25% aluminum chloride, 25% aluminum sulfate, and 15.5% ferric sulfate) and 5 experimental adrenergics (0.1% and 0.01% HCl-epinephrine, 0.05% HCl-tetrahydrozoline, 0.05% HCl-oxymetazoline, and 10% HCl-phenylephrine). As many as 120 specimens (60 light body and 60 medium body) were mixed with 20 μl of each of 10 gingival displacement agents, and the time to achieve maximum viscosity was measured with a viscometer. The setting times of these specimens were compared with the control group of 12 specimens, which were polymerized without contact with the displacement agents. The experiments were performed in two environments: 23°C and 37°C (± 0.1°C). Individual and average polymerization time compatibility indices (PTCI) were calculated. Data were analyzed by 2-way ANOVA (α = 0.05). The evaluated chemical displacement agents from both groups changed the setting time of light- and medium-body PE. The negative individual PTCI values achieved astringent (20% aluminum chloride) with two PE in both temperature environments. The average PTCI values of the experimental displacement agents at laboratory and intraoral temperatures were significantly higher than the conventional agents. The present findings suggest that experimental retraction agents can be recommended clinically as gingival margin displacement agents with minimal effects on the setting time of medium- and light-body polyether impression materials; however, direct

  12. Investigation of the primary plasticisers present in polyvinyl chloride (PVC) products currently authorised as food contact materials.

    Science.gov (United States)

    Carlos, Katherine S; de Jager, Lowri S; Begley, Timothy H

    2018-03-15

    PVC is a common food contact material that is usually plasticised to increase its flexibility. Phthalates are one class of chemical compounds that are often used as plasticisers in PVC in a wide range of industries. They may be used in packaging materials for foods and can also be found in components of certain food processing equipment such as conveyor belts and tubing. Transfer of plasticisers from packaging to foods can occur. In recent years, there has been increased interest in understanding the health effects of phthalates, as well as the possible human exposure levels. However, there is limited information available about the routes of exposure to phthalates. In July 2014, the Chronic Hazard Advisory Panel (CHAP) produced a report for the U.S. Consumer Product Safety Commission detailing the potential health hazards of phthalates and phthalate alternatives. This report listed diet as one factor contributing greater than or equal to 10% of total phthalate exposure. As a result of this report, the U.S. Food and Drug Administration (FDA) is interested in determining the types of the primary plasticiser present in food packaging and processing materials as well as their concentrations. An investigation was conducted of 56 different samples of PVC food packaging and food processing materials available in the US market using a solvent extraction and GC-MS analysis. Nine different plasticisers including three phthalates, di(2-ethylhexyl) phthalate, diisononyl phthalate and diisodecyl phthalate, were identified in the products tested. The plasticiser concentrations ranged from 1 to 53% depending on the types of food contact materials and the type of plasticiser. Overall, it appears that manufacturers are switching away from phthalates as their primary plasticiser to alternate compounds such as ESBO, ATBC, DEHT, DINCH, DEHA and DINA.

  13. [Biocompatibility of crown and bridge materials. 1. Substances in contact with dentin].

    Science.gov (United States)

    Klotzer, W T

    1989-11-01

    It is mandatory that the materials and drugs used in restorative dentistry be free from side effects resulting in potential tooth loss or irreversible damage to vital dental tissues. Up to now there have been no reliable in vitro methods available for the evaluation of pulp reactions. Since numerous different materials and drugs are successively applied to prepared dentine, pulp reactions are caused by cumulative action, and the causative factors, except for extremely toxic substances, cannot be revealed by clinical and/or posttreatment studies alone. At present, the evaluation of pulp reactions must still rely on histologic studies using human or animal teeth. Reports on pulp reactions to materials and drugs are reviewed. Few dependable figures have been reported on pulp reactions to dentinal medication, "sterilization", disinfectants and on the biologic response to and effectiveness of varnishes, liners, desensitizing agents, smear-layer removers, etc. Resins and composite materials seem to provoke acute reactions, mainly by the heat generated during setting, and chronic reactions due to the stimulation of bacterial growth. Except for glass ionomer cements, most of the publications show a high degree of agreement on the tissue reactions to luting agents. Regarding dentine bonding agents, however, it has not been possible to draw any conclusions, so far.

  14. Long-term stability of earthen materials in contact with acidic tailings solutions

    International Nuclear Information System (INIS)

    Peterson, S.R.; Erikson, R.L.; Gee, G.W.

    1982-11-01

    The objectives of the studies documented in this report were to use experimental and geochemical computer modeling tools to assess the long-term environmental impact of leachate movement from acidic uranium mill tailings. Liner failure (i.e., an increase in the permeability of the liner material) was not found to be a problem when various acidic tailings solutions leached through liner materials for periods up to 3 years. On the contrary, materials that contained over 30% clay showed a decrease in permeability with time in the laboratory columns. The high clay materials tested appear suitable for lining tailings impoundment ponds. The decreases in permeability are attributed to pore plugging resulting from the precipitation of minerals and solids. This precipitation takes place due to the increase in pH of the tailings solution brought about by the buffering capacity of the soil. Geochemical modeling predicts, and x-ray characterization confirms, that precipitation of solids from solution is occurring in the acidic tailings solution/liner interactions studied. In conclusion the same mineralogical changes and contaminant reactions predicted by geochemical modeling and observed in laboratory studies were found at a drained evaporation pond (Lucky Mc in Wyoming) with a 4 year history of acid attack

  15. Modal analysis of graphene-based structures for large deformations, contact and material nonlinearities

    Science.gov (United States)

    Ghaffari, Reza; Sauer, Roger A.

    2018-06-01

    The nonlinear frequencies of pre-stressed graphene-based structures, such as flat graphene sheets and carbon nanotubes, are calculated. These structures are modeled with a nonlinear hyperelastic shell model. The model is calibrated with quantum mechanics data and is valid for high strains. Analytical solutions of the natural frequencies of various plates are obtained for the Canham bending model by assuming infinitesimal strains. These solutions are used for the verification of the numerical results. The performance of the model is illustrated by means of several examples. Modal analysis is performed for square plates under pure dilatation or uniaxial stretch, circular plates under pure dilatation or under the effects of an adhesive substrate, and carbon nanotubes under uniaxial compression or stretch. The adhesive substrate is modeled with van der Waals interaction (based on the Lennard-Jones potential) and a coarse grained contact model. It is shown that the analytical natural frequencies underestimate the real ones, and this should be considered in the design of devices based on graphene structures.

  16. Measurement of Creep Properties of Ultra-High-Temperature Materials by a Novel Non-Contact Technique

    Science.gov (United States)

    Hyers, Robert W.; Lee, Jonghyun; Rogers, Jan R.; Liaw, Peter K.

    2007-01-01

    A non-contact technique for measuring the creep properties of materials has been developed and validated as part of a collaboration among the University of Massachusetts, NASA Marshall Space Flight Center Electrostatic Levitation Facility (ESL), and the University of Tennessee. This novel method has several advantages over conventional creep testing. The sample is deformed by the centripetal acceleration from the rapid rotation, and the deformed shapes are analyzed to determine the strain. Since there is no contact with grips, there is no theoretical maximum temperature and no concern about chemical compatibility. Materials may be tested at the service temperature even for extreme environments such as rocket nozzles, or above the service temperature for accelerated testing of materials for applications such as jet engines or turbopumps for liquid-fueled engines. The creep measurements have been demonstrated to 2400 C with niobium, while the test facility, the NASA MSFC ESL, has processed materials up to 3400 C. Furthermore, the ESL creep method employs a distribution of stress to determine the stress exponent from a single test, versus the many tests required by conventional methods. Determination of the stress exponent from the ESL creep tests requires very precise measurement of the surface shape of the deformed sample for comparison to deformations predicted by finite element models for different stress exponents. An error analysis shows that the stress exponent can be determined to about 1% accuracy with the current methods and apparatus. The creep properties of single-crystal niobium at 1985 C showed excellent agreement with conventional tests performed according to ASTM Standard E-139. Tests on other metals, ceramics, and composites relevant to rocket propulsion and turbine engines are underway.

  17. [Determination of bisphenol A from toys and food contact materials by derivatization and gas chromatography-mass spectrometry].

    Science.gov (United States)

    Gao, Yonggang; Zhang, Yanyan; Gao, Jianguo; Zhang, Huiling; Zheng, Lisha; Chen, Jing

    2012-10-01

    A method was developed for the determination of bisphenol A (BPA) in toys and food contact materials. The BPA was extracted with Soxhlet extraction method from the sample and reacted with acetic anhydride. The final product was determined by gas chromatography-mass spectrometry (GC-MS). To achieve the optimum derivatization performance, the derivatization time and dosage of derivatization reagent etc. were investigated. Under the optimized experimental conditions, the final product was stable and the peak shape was good. The linearity of the derivative was good in the range of 0.05 to 50 mg/L with the correlation coefficient (r2) above 0.999. The recoveries ranged from 80% to 93% at the spiked levels of 0.05, 1.00, 10.00 mg/kg with the relative standard deviations (RSDs) less than 3.7%. The limit of detection (S/N = 3) was 10 microg/kg. The method is accurate and has high recovery. The method is suitable for the inspection of bisphenol A in toys and food contact materials.

  18. Utilization of cellulosic materials through enzymic hydrolysis. 11. Preliminary assessment of an integrated processing scheme

    Energy Technology Data Exchange (ETDEWEB)

    Wilke, C R; Cysewski, G R; Yang, R D

    1976-01-01

    An integrated processing scheme is described for the conversion of a cellulose waste (newsprint) to sugars by enzymic hydrolysis and then to ethanol and yeast by fermentation. The unconverted solids are burned to produce process energy requirements and surplus electric power. With the preliminary design at an estimate total capital investment of $33.4 x 10/sup 6/, 95% ethanol may be produced FOB (free on board) the plant for approx.61 cents/gal, assuming zero cost for cellulosic feed; taking into account interest rates and taxes and a cellulose feed cost of $20/ton the figure becomes $1.67/gal.

  19. Fractionation of extracts from paper and board food contact materials forin vitroscreening of toxicity

    DEFF Research Database (Denmark)

    Bengtström, Linda; Trier, Xenia; Granby, Kit

    2014-01-01

    materials, information on the exposure as well as on the toxicity of substances in the packaging must be obtained. This study describes a comprehensive method for the extraction and fractionation of substances present in paper and board FCMs for further investigation by in vitro testing and chemical...... assay. Both raw extracts and two of the fractions of the raw extracts gave a positive response in the AhR assay. The strategy of extraction followed by fractionation offers a powerful tool in order to make the workflow for screening FCMs for potentially adverse effects more efficient....

  20. Multicenter evaluation of the commutability of a potential reference material for harmonization of enzyme activities

    NARCIS (Netherlands)

    Scharnhorst, V.; Apperloo, J.J.; Baadenhuijsen, H.; Vader, H.L.

    2014-01-01

    Standardization of laboratory results allows for the use of common reference intervals and can be achieved via calibration of field methods with secondary reference materials. These harmonization materials should be commutable, i.e., they produce identical numerical results independent of assay

  1. Risk assessment derived from migrants identified in several adhesives commonly used in food contact materials.

    Science.gov (United States)

    Canellas, E; Vera, P; Nerín, C

    2015-01-01

    Adhesives are used to manufacture multilayer materials, where their components pass through the layers and migrate to the food. Nine different adhesives (acrylic, vinyl and hotmelt) and their migration in 21 laminates for future use as market samples have been evaluated and risk assessment has been carried out. A total of 75 volatiles and non volatile compounds were identified by gas chromatography-mass spectrometry and ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry. Most of the compounds migrated below their specific migration limit (SML), lowest observed adverse effect level (LOAEL), no observed adverse effect level (NOAEL) and values recommended by Cramer. Six compounds classified as high toxicity class III according to Cramer classification, migrated over their SML and exposure values recommended by Cramer, when they were applied in the full area of the packaging. Nevertheless, these adhesives fulfill the threshold in the real application as they are applied in a small area of the packaging. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. The biofilm-positive Staphylococcus epidermidis isolates in raw materials, foodstuffs and on contact surfaces in processing plants.

    Science.gov (United States)

    Schlegelová, J; Babák, V; Holasová, M; Dendis, M

    2008-01-01

    Isolates from the "farm to fork" samples (182 isolates from 2779 samples) were examined genotypically (icaAB genes) and phenotypically (in vitro biofilm formation, typical growth on Congo red agar; CRA) with the aim to assess the risk of penetration of virulent strains of Staphylococcus epidermidis into the food chain. The contamination of meat and milk products was significantly higher in comparison with raw materials. Contamination of contact surfaces in the meat-processing plants was significantly lower than that of contact surfaces in the dairy plants. The ica genes (which precondition the biofilm formation) were concurrently detected in 20 isolates that also showed a typical growth on CRA. Two ica operon-negative isolates produced biofilm in vitro but perhaps by an ica-independent mechanism. The surfaces in the dairy plants and the milk products were more frequently contaminated with ica operon-positive strains (2.3 and 1.2 % samples) than the other sample types (0-0.6 % samples).

  3. Weight loss studies of fastener materials corrosion in contact with timbers treated with copper azole and alkaline copper quaternary compounds

    Energy Technology Data Exchange (ETDEWEB)

    Kear, Gareth [Building Research Association of New Zealand (BRANZ) Ltd., Science and Engineering Services, Private Bag 50 908, Porirua City 5240 (New Zealand)], E-mail: G.Kear@soton.ac.uk; Wu Haizhen; Jones, Mark S. [Building Research Association of New Zealand (BRANZ) Ltd., Science and Engineering Services, Private Bag 50 908, Porirua City 5240 (New Zealand)

    2009-02-15

    Corrosion rates of mild steel, AISI 316 stainless steel and hot-dipped galvanised steel in contact with preservative-treated Pinus radiata have been determined using four distinct accelerated (49 {+-} 1 deg. C) and non-accelerated (21 {+-} 2 deg. C) weight loss methodologies. The data were measured as a function of timber moisture content and copper concentration over periods of exposure ranging from 2 weeks to 14 months. The results show that the corrosion resistance of the stainless steel was not influenced by classification or magnitude of preservative loading. Corrosion rates of this material were multiple orders of magnitude lower than those of the mild and galvanised steels. In most instances, corrosion rates of hot-dipped galvanised layers in contact with alkaline copper quaternary-treated timbers were up to a factor of 10 times, or greater, than those measured for copper-chrome-arsenate treatments. A direct negative influence of copper ion concentration on the corrosion resistance of mild steel was also observed for each preservative type.

  4. A friction test between steel and a brittle material at high contact pressures and high sliding velocities

    Directory of Open Access Journals (Sweden)

    Picart D.

    2012-08-01

    Full Text Available Our aim is to characterize the interface behaviour between an aggregate material and steel. This work focuses on contact pressures and sliding velocities reaching 100 MPa and 10 m/s. The set-up consists in a cylindrical sample of the aggregate material which slips into a steel tube. The tube is both a confinement vessel and a sliding surface. Thanks to confinement, the material can be tested under high stresses without failure. The interface pressure is generated by an axial compression. The sample is pressed on a spring, so it can be simultaneously compressed and rubbed on the tube. The set-up has been tested in the case of a quasi-static loading and the 100 MPa pressure has been reached. Then the set-up was mounted on a Split Hopkinson Pressure Bar device in order to reach higher velocities. Numerical simulations have been realized to check the feasibility and the relevance of this dynamic test. These results are analysed and compared to the experimental ones.

  5. Mesothelioma among employees with likely contact with in-place asbestos-containing building materials.

    Science.gov (United States)

    Anderson, H A; Hanrahan, L P; Schirmer, J; Higgins, D; Sarow, P

    1991-12-31

    The occurrence of mesothelioma is a sentinel event in occupational and environmental disease. A mesothelioma surveillance system was established utilizing existing computerized Wisconsin vital statistics data maintained since 1959 and a Cancer Reporting System (CRS) established in 1978. Review of the death certificate listing of usual occupation and industry from 487 mesothelioma deaths in Wisconsin from 1959 to 1989 led to the investigation of 41 persons with likely exposure to inplace asbestos-containing building materials (ACBM): 12 school teachers, 10 school maintenance employees, 7 public building maintenance workers, 5 private building maintenance workers, and 7 commercial and factory workers performing maintenance activities. For 10 (34%) of the 29 maintenance workers the only source of asbestos exposure identified was their maintenance work. For five (17%) histories indicated some prior employment in occupations and industries with probable asbestos exposures. Opportunities for indirect occupational exposure were identified for ten who had been employed in the residential construction industry. One maintenance worker was exposed to asbestos in the household and another had neighborhood exposure. For 9 (75%) of the school teachers, the only identifiable potential source of asbestos exposure was derived from in-place ACBM in schools. One teacher had spent a season in the merchant marine aboard an iron ore-hauling ship and 2 had worked in the residential construction industry. Two of the teachers were sisters, and in two instances, two teachers had taught in the same school facility. We conclude that individuals occupationally exposed to in-place ACBM are at risk for the subsequent development of mesothelioma.

  6. Analysis of the thermal response of a BWR Mark-I containment shell to direct contact by molten core materials

    International Nuclear Information System (INIS)

    Kress, T.S.; Cleveland, J.C.

    1988-01-01

    This study was undertaken to evaluate the thermal response of a BWR Mark-I containment shell in the event of an accident severe enough for molten core materials to fall into the cavity beneath the rector vessel and eventually come into direct contact with the shell. An existing ORNL three-dimensional transient heat transport computer code, HEATING-6, was used for a specific 2-D case (and variations) for which representative melt/shell boundary conditions required as input were available from other studies. In addition to the use of HEATING-6, a simplified analytical steady-state correlation was developed and given the name BWR Liner Analysis Program (BWRLAP). BWRLAP was ''benchmarked'' by comparison with HEATING-6 and was then used to make a number of parametric calculations to investigate the sensitivities of the results to the inputs. 5 refs., 11 figs., 2 tabs

  7. Procedure for the creation of reproducible acoustic coupling using the ultrasonic contact method for nondestructive testing of materials

    International Nuclear Information System (INIS)

    Tomilov, B.V.

    1979-01-01

    The transducer is pressed to the specimen, a lubricating coating being applied as an intermediate layer. By means of a vibrator belonging to the transducer there are generated vibrations, the growth rate of the amplitude of the reflected signal picked up being observed. This growth rate is monotonously decreasing. If the growth rate is abruptly decreasing or if the amplitude of the measured signal remains constant the vibrator is turned off, because now good acoustic contact is established. After a short time of waiting for the residual stress of the transducer to decay, recording of the ultrasonic parameters may then be taken up. The method can be applied to thickness measurements and inhomogeneous materials with low surface quality. (RW) [de

  8. Exploring the chemistry of complex samples by tentative identification and semi-quantification: a food contact material case

    DEFF Research Database (Denmark)

    Pieke, Eelco Nicolaas; Smedsgaard, Jørn; Granby, Kit

    2017-01-01

    to retrieve the most likely chemical match from a structure database. In addition, TOF-only data is used to estimate analyte concentration via semi-quantification. The method is demonstrated in recycled paper food contact material (FCM). Here, 585 chromatographic peaks were discovered, of which 117 were...... data. Overall, the described method is a valuable chemical exploration tool for non-identified substances, but also may be used as a preliminary prioritization tool for substances expected to have the highest health impact, for example in FCMs....... elucidation of a vast number of unknowns, of which only a fraction may be relevant. Here, we present an exploration and prioritization approach based on high resolution mass spectrometry. The method uses algorithm-based precursor/product-ion correlations on Quadrupole-Time of Flight (Q-TOF) MS/MS data...

  9. EFSA CEF Panel (Panel on Food Contac t Materials, Enzymes, Flavourings and Processing Aids , 2013. Scientific Opinion on Flavouring Group Evaluation 2 07 (FGE.2 07 )

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Binderup, Mona-Lise; Lund, Pia

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate the genotoxic potential of one flavouring substance, 2,6-dimethyl-2,5,7-octatriene-1-ol acetate [FL-no: 09.931], from subgroup 1.1.2 of FGE.19, which...... is considered to be representative for four substances, 12-beta-santalen-14-ol [FL-no: 02.216], 12-alpha-santalen-14-ol [FL-no: 02.217], santalyl acetate [FL-no: 09.034] and santalyl phenylacetate [FL-no: 09.712], from subgroup 2.1 of FGE.19. The Flavour Industry has provided genotoxicity studies......-no: 09.034] and santalyl phenylacetate [FL-no: 09.712] from FGE.19 subgroup 2.1 for which 2,6-dimethyl-2,5,7-octatriene-1-ol acetate [FL-no: 09.931] is representative. © European Food Safety Authority, 2013...

  10. Evaluation of coal combustion byproducts as soil liming materials - their influence on soil pH and enzyme activities

    Energy Technology Data Exchange (ETDEWEB)

    McCarty, G W; Siddaramappa, R; Wright, R J; Codling, E E; Gao, G

    1994-03-01

    To evaluate coal combustion byproducts as liming materials and address issues related to soil quality, the authors compared the influence of different amounts of four combustion byproducts (fly ash and bed ash from a fluidized bed combustion furnace, lime-injected multistage burner residue, and spray dryer residue) and CaCO[sub 3] on soil pH and activities of urease, phosphatase, arylsulfatase, and dehydrogenase in an acidic soil. Studies comparing the influence of the combustion byproducts and CaCO[sub 3] on soil pH showed that on weight basis of application, substantial differences were observed in the ability of these materials to influence soil pH but that such differences decreased markedly after the data were transformed to a CaCO[sub 3] equivalent basis of application. Analysis of covariance for these transformed data indicated that whereas the liming abilities of fly ash and CaCO[sub 3] were not significantly different when compared on the CaCO[sub 3] equivalent basis, those of bed ash, multistage burner residue, and spray dryer residue were less than that of CaCO[sub 3]. Studies comparing the influence of the byproducts and CaCO[sub 3] on soil enzyme activities showed that the effect of these liming materials on the enzyme activities studied was largely due to their influence on soil pH. These studies showed that the combustion byproducts tested functioned as soil liming materials in a manner similar to that of CaCO[sub 3] and seemed to have little adverse effect on soil quality.

  11. Development of high-performance functional materials for enzyme immobilization by the use of ionizing radiation

    International Nuclear Information System (INIS)

    SALIM, R.D.M.

    2013-01-01

    Isomerization of glucose to fructose was carried out using Glucose isomerase (GI) that immobilized by entrapment into Poly (acrylic acid) P (AA) and Poly (acrylic acid-co- 2-Acrylamido 2- methyl Propane sulfonic acid) P (AA-co-AMPS) polymer networks, the enzyme carriers were prepared by radiation induced co-polymerization in presence of (Methylene- bis acrylamide) (MBAA) as a crosslinking agent. Effects of immobilization conditions such as irradiation dose, methylene bis acrylamide concentration, comonomer composition, and amount of GI were investigated. The influence of reaction conditions on the activity of immobilized GI were studied, the optimum ph value of reaction solution is 7.5 and reaction temperature is 65 degree C. The immobilized GI into P (AA-co-AMPS) and P (AA) polymer networks retained 81% and 69%,respectively, of its initial activity after recycled for 15 times while it retained 87% and 71% ,respectively ,of its initial activity after stored at 4 degree C for 48 days , The Km values of free and immobilized GI onto P(AA-co-AMPS) and onto P(AA) matrices were found to be 34, 29.2 , 14.5 mg/ml respectively while the Vmax Values calculated to be 3.87 ,1.6,0.79 mg/ml.min, respectively, Therefore , the bio conversion of glucose to fructose can be successfully performed by GI entrapped into P (AA-co-AMPS) hydrogel .

  12. In situ enzyme aided adsorption of soluble xylan biopolymers onto cellulosic material.

    Science.gov (United States)

    Chimphango, Annie F A; Görgens, J F; van Zyl, W H

    2016-06-05

    The functional properties of cellulose fibers can be modified by adsorption of xylan biopolymers. The adsorption is improved when the degree of biopolymers substitution with arabinose and 4-O-methyl-glucuronic acid (MeGlcA) side groups, is reduced. α-l-Arabinofuranosidase (AbfB) and α-d-glucuronidase (AguA) enzymes were applied for side group removal, to increase adsorption of xylan from sugarcane (Saccharum officinarum L) bagasse (BH), bamboo (Bambusa balcooa) (BM), Pinus patula (PP) and Eucalyptus grandis (EH) onto cotton lint. The AguA treatment increased the adsorption of all xylans by up to 334%, whereas, the AbfB increased the adsorption of the BM and PP by 31% and 44%, respectively. A combination of AguA and AbfB treatment increased the adsorption, but to a lesser extent than achieved with AguA treatment. This indicated that the removal of the glucuronic acid side groups provided the most significant increase in xylan adsorption to cellulose, in particular through enzymatic treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Direct ethanol production from cellulosic materials at high temperature using the thermotolerant yeast Kluyveromyces marxianus displaying cellulolytic enzymes

    Energy Technology Data Exchange (ETDEWEB)

    Yanase, Shuhei; Yamada, Ryosuke; Ogino, Chiaki; Kondo, Akihiko [Kobe Univ. (Japan). Dept. of Chemical Science and Engineering; Hasunuma, Tomohisa; Tanaka, Tsutomu; Fukuda, Hideki [Kobe Univ. (Japan). Organization of Advanced Science and Technology

    2010-09-15

    To exploit cellulosic materials for fuel ethanol production, a microorganism capable of high temperature and simultaneous saccharification-fermentation has been required. However, a major drawback is the optimum temperature for the saccharification and fermentation. Most ethanol-fermenting microbes have an optimum temperature for ethanol fermentation ranging between 28 C and 37 C, while the activity of cellulolytic enzymes is highest at around 50 C and significantly decreases with a decrease in temperature. Therefore, in the present study, a thermotolerant yeast, Kluyveromyces marxianus, which has high growth and fermentation at elevated temperatures, was used as a producer of ethanol from cellulose. The strain was genetically engineered to display Trichoderma reesei endoglucanase and Aspergillus aculeatus {beta}-glucosidase on the cell surface, which successfully converts a cellulosic {beta}-glucan to ethanol directly at 48 C with a yield of 4.24 g/l from 10 g/l within 12 h. The yield (in grams of ethanol produced per gram of {beta}-glucan consumed) was 0.47 g/g, which corresponds to 92.2% of the theoretical yield. This indicates that high-temperature cellulose fermentation to ethanol can be efficiently accomplished using a recombinant K. marxianus strain displaying thermostable cellulolytic enzymes on the cell surface. (orig.)

  14. Porous Aromatic Framework 48/Gel Hybrid Material Coated Solid-Phase Microextraction Fiber for the Determination of the Migration of Styrene from Polystyrene Food Contact Materials.

    Science.gov (United States)

    Jin, Yuanyuan; Li, Zhongyue; Yang, Lei; Xu, Jun; Zhao, Le; Li, Zhonghao; Niu, Jiajia

    2017-01-17

    A novel solid-phase microextraction (SPME) fiber was fabricated by a porous aromatic framework 48 (PAF-48)/gel hybrid material through a sol-gel process. PAF-48 is a porous organic framework (POF) material that was polymerized from 1,3,5-triphenylbenzene. The uniform pore structure, high surface area, continuous conjugate network, and hydrophobicity make PAF-48 expected to have special abilities to absorb and extract styrene as well as some other harmful volatile aromatic compounds (VACs). The PAF-48/gel-coated fiber was explored for the extraction of styrene and six VACs (benzene, toluene, ethylbenzene, and xylenes) from aqueous food simulants followed by gas chromatography (GC) separation. The fiber was found to be very sensitive for the determination of the target molecules with wide linear ranges (0.1-200 or 500 μg·kg -1 ), low limits of detection (LODs, 0.003-0.060 μg·kg -1 ), acceptable precisions (intraday relative standard deviation, RSD 200 times). Particularly for styrene, the PAF-48/gel-coated fiber exhibited a much lower LOD (0.006 μg·kg -1 ) compared with most of the reported fibers. Moreover, the PAF-48/gel-coated fiber had a high extraction selectivity for styrene and VACs over alcohols, phenols, aromatic amines, and alkanes and show a molecular sieving effect for the different molecule sizes. Finally, the PAF-48/gel-coated SPME fiber was successfully applied in GC for the determination of the specific migrations of styrene and VACs from polystyrene (PS) plastic food contact materials (FCMs).

  15. Study of non-contact measurement of the thermal expansion coefficients of materials based on laser feedback interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Fasong [The State Key Lab of Precision Measurement Technology and Instrument, Department of Precision Instruments, Tsinghua University, Beijing 100084 (China); Departments of Physics, College of Science, Beijing University of Chemical Technology, Beijing 100029 (China); Tan, Yidong; Zhang, Shulian, E-mail: zsl-dpi@mail.tsinghua.edu.cn [The State Key Lab of Precision Measurement Technology and Instrument, Department of Precision Instruments, Tsinghua University, Beijing 100084 (China); Lin, Jing; Ding, Yingchun [Departments of Physics, College of Science, Beijing University of Chemical Technology, Beijing 100029 (China)

    2015-04-15

    The noncooperative and ultrahigh sensitive length measurement approach is of great significance to the study of a high-precision thermal expansion coefficient (TEC) determination of materials at a wide temperature range. The novel approach is presented in this paper based on the Nd:YAG microchip laser feedback interferometry with 1064 nm wavelength, the beam frequency of which is shifted by a pair of acousto-optic modulators and then the heterodyne phase measurement technique is used. The sample is placed in a muffle furnace with two coaxial holes opened on the opposite furnace walls. The measurement beams are perpendicular and coaxial on each surface of the sample, the configuration which can not only achieve the length measurement of sample but also eliminate the influence of the distortion of the sample supporter. The reference beams inject on the reference mirrors which are put as possible as near the holes, respectively, to eliminate the air disturbances and the influence of thermal lens effect out of the furnace chamber. For validation, the thermal expansion coefficients of aluminum and steel 45 samples are measured from room temperature to 748 K, which proved measurement repeatability of TECs is better than 0.6 × 10{sup −6}(K{sup −1}) at the range of 298 K–598 K and the high-sensitive non-contact measurement of the low reflectivity surface induced by the oxidization of the samples at the range of 598 K–748 K.

  16. (Q)SAR tools for priority setting: A case study with printed paper and board food contact material substances.

    Science.gov (United States)

    Van Bossuyt, Melissa; Van Hoeck, Els; Raitano, Giuseppa; Manganelli, Serena; Braeken, Els; Ates, Gamze; Vanhaecke, Tamara; Van Miert, Sabine; Benfenati, Emilio; Mertens, Birgit; Rogiers, Vera

    2017-04-01

    Over the last years, more stringent safety requirements for an increasing number of chemicals across many regulatory fields (e.g. industrial chemicals, pharmaceuticals, food, cosmetics, …) have triggered the need for an efficient screening strategy to prioritize the substances of highest concern. In this context, alternative methods such as in silico (i.e. computational) techniques gain more and more importance. In the current study, a new prioritization strategy for identifying potentially mutagenic substances was developed based on the combination of multiple (quantitative) structure-activity relationship ((Q)SAR) tools. Non-evaluated substances used in printed paper and board food contact materials (FCM) were selected for a case study. By applying our strategy, 106 out of the 1723 substances were assigned 'high priority' as they were predicted mutagenic by 4 different (Q)SAR models. Information provided within the models allowed to identify 53 substances for which Ames mutagenicity prediction already has in vitro Ames test results. For further prioritization, additional support could be obtained by applying local i.e. specific models, as demonstrated here for aromatic azo compounds, typically found in printed paper and board FCM. The strategy developed here can easily be applied to other groups of chemicals facing the same need for priority ranking. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Determination of melamine in food contact materials using an electrode modified with gold nanoparticles and reduced graphene oxide

    International Nuclear Information System (INIS)

    Chen, Ningning; Zhang, Cuiling; Zhao, Kai; Xian, Yuezhong; Cheng, Yuxiao; Li, Chen

    2015-01-01

    We describe an electrochemical sensor for melamine based on a glassy carbon electrode (GCE) modified with reduced graphene oxide that was decorated with gold nanoparticles (AuNP/rGO). The AuNPs/rGO nanocomposite was synthesized by co-reduction of Au(III) and graphene oxide and characterized by transmission electron microscopy, Raman spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The response of the modified GCE to melamine was investigated by using hexacyanoferrate as an electrochemical reporter. It is found that the electrochemical response to hexacyanoferrate is increasingly suppressed by increasing concentration of melamine. This is attributed to competitive adsorption of melamine at the AuNP/rGO composite through the interaction between the amino groups of melamine and the AuNPs. The presence of rGO, in turn, provides a platform for a more uniform distribution of the AuNPs and enhances the electron transfer rate of the redox reaction. The findings were used to develop a sensitive method for the determination of melamine. Under optimized conditions, the redox peak current of hexacyanoferrate at a working voltage of 171 mV (vs. SCE) is linearly related to the concentration of melamine in 5.0 to 50 nM range. The method was successfully applied to the determination of melamine in food contact materials. (author)

  18. Dermatitis, contact (image)

    Science.gov (United States)

    This picture shows a skin inflammation (dermatitis) caused by contact with a material that causes an allergic reaction in this person. Contact dermatitis is a relatively common condition, and can be caused ...

  19. Genotoxicity testing approaches for the safety assessment of substances used in food contact materials prior to their authorization in the European Union.

    Science.gov (United States)

    Bolognesi, Claudia; Castoldi, Anna F; Crebelli, Riccardo; Barthélémy, Eric; Maurici, Daniela; Wölfle, Detlef; Volk, Katharina; Castle, Laurence

    2017-06-01

    Food contact materials are all materials and articles intended to come directly or indirectly into contact with food. Before being included in the positive European "Union list" of authorized substances (monomers, other starting substances and additives) for plastic food contact materials, the European Food Safety Authority (EFSA) must assess their safety "in use". If relevant for risk, the safety of the main impurities, reaction and degradation products originating from the manufacturing process is also evaluated. Information on genotoxicity is always required irrespective of the extent of migration and the resulting human exposure, in view of the theoretical lack of threshold for genotoxic events. The 2008 EFSA approach, requiring the testing of food contact materials in three in vitro mutagenicity tests, though still acceptable, is now superseded by the 2011 EFSA Scientific Committee's recommendation for only two complementary tests including a bacterial gene mutation test and an in vitro micronucleus test, to detect two main genetic endpoints (i.e., gene mutations and chromosome aberrations). Follow-up of in vitro positive results depends on the type of genetic effect and on the substance's systemic availability. In this study, we provide an analysis of the data on genotoxicity testing gathered by EFSA on food contact materials for the period 1992-2015. We also illustrate practical examples of the approaches that EFSA took when evaluating "non standard" food contact chemicals (e.g., polymeric additives, oligomer or other reaction mixtures, and nanosubstances). Additionally, EFSA's experience gained from using non testing methods and/or future possibilities in this area are discussed. Environ. Mol. Mutagen. 58:361-374, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  20. Suppression of material transfer at contacting surfaces: the effect of adsorbates on Al/TiN and Cu/diamond interfaces from first-principles calculations

    Science.gov (United States)

    Feldbauer, Gregor; Wolloch, Michael; Bedolla, Pedro O.; Redinger, Josef; Vernes, András; Mohn, Peter

    2018-03-01

    The effect of monolayers of oxygen (O) and hydrogen (H) on the possibility of material transfer at aluminium/titanium nitride (Al/TiN) and copper/diamond (Cu/Cdia) interfaces, respectively, were investigated within the framework of density functional theory (DFT). To this end the approach, contact, and subsequent separation of two atomically flat surfaces consisting of the aforementioned pairs of materials were simulated. These calculations were performed for the clean as well as oxygenated and hydrogenated Al and Cdia surfaces, respectively. Various contact configurations were considered by studying several lateral arrangements of the involved surfaces at the interface. Material transfer is typically possible at interfaces between the investigated clean surfaces; however, the addition of O to the Al and H to the Cdia surfaces was found to hinder material transfer. This passivation occurs because of a significant reduction of the adhesion energy at the examined interfaces, which can be explained by the distinct bonding situations.

  1. Skin cooling on contact with cold materials: the effect of blood flow during short-term exposures.

    Science.gov (United States)

    Jay, Ollie; Havenith, George

    2004-03-01

    This study investigates the effect of blood flow upon the short-term (cooling response in order to ascertain whether sufferers of circulatory disorders, such as the vasospastic disorder Raynaud's disease, are at a greater risk of cold injury than people with a normal rate of blood flow. Eight female volunteers participated, touching blocks of stainless steel and nylon with a finger contact force of 2.9 N at a surface temperature of -5 degrees C under occluded and vasodilated conditions. Contact temperature (Tc) of the finger pad was measured over time using a T-type thermocouple. Forearm blood flow was measured using strain gauge plethysmography. Contact cooling responses were analysed by fitting a modified Newtonian cooling curve. A significant difference was found between the starting skin temperatures for the two blood flow conditions (Peffect of blood flow was found upon any of the derived cooling curve parameters characterizing the skin cooling response (P>0.05). It is hypothesized that the finger contact force used (2.9 N) and the resultant pressure upon the tissue of the contact finger pad restricted the blood supply to the contact area under both blood flow conditions; therefore, no effect of blood flow was found upon the parameters describing the contact cooling response. Whilst the findings of this study are sufficient to draw a conclusion for those in a working environment, i.e. contact forces below 2.9 N will seldom be encountered, a further study will be required to ascertain conclusively whether blood flow does affect the contact cooling response at a finger contact force low enough to allow unrestricted blood flow to the finger pad. Further protocol improvements are also recommended.

  2. Integrating bioassays and analytical chemistry as an improved approach to support safety assessment of food contact materials.

    Science.gov (United States)

    Veyrand, Julien; Marin-Kuan, Maricel; Bezencon, Claudine; Frank, Nancy; Guérin, Violaine; Koster, Sander; Latado, Hélia; Mollergues, Julie; Patin, Amaury; Piguet, Dominique; Serrant, Patrick; Varela, Jesus; Schilter, Benoît

    2017-10-01

    Food contact materials (FCM) contain chemicals which can migrate into food and result in human exposure. Although it is mandatory to ensure that migration does not endanger human health, there is still no consensus on how to pragmatically assess the safety of FCM since traditional approaches would require extensive toxicological and analytical testing which are expensive and time consuming. Recently, the combination of bioassays, analytical chemistry and risk assessment has been promoted as a new paradigm to identify toxicologically relevant molecules and address safety issues. However, there has been debate on the actual value of bioassays in that framework. In the present work, a FCM anticipated to release the endocrine active chemical 4-nonyphenol (4NP) was used as a model. In a migration study, the leaching of 4NP was confirmed by LC-MS/MS and GC-MS. This was correlated with an increase in both estrogenic and anti-androgenic activities as measured with bioassays. A standard risk assessment indicated that according to the food intake scenario applied, the level of 4NP measured was lower, close or slightly above the acceptable daily intake. Altogether these results show that bioassays could reveal the presence of an endocrine active chemical in a real-case FCM migration study. The levels reported were relevant for safety assessment. In addition, this work also highlighted that bioactivity measured in migrate does not necessarily represent a safety issue. In conclusion, together with analytics, bioassays contribute to identify toxicologically relevant molecules leaching from FCM and enable improved safety assessment.

  3. The influence of Saccharomyces cerevisiae enzyme ratio on preparation virgin coconut oil for candidate in-house reference materials

    Science.gov (United States)

    Rohyami, Yuli; Anjani, Rafika Debby; Purwanti, Napthalina Putri

    2017-03-01

    Virgin coconut oil is an excellent product which has result of oil processing business opportunities in the international market. Standardization of virgin coconut oil necessary to satisfy the requirements industry needs. This research is expected as procedure preparation of reference materials. Preparation of virgin coconut oil by Sacharomycescerevisiaeenzyme. Based on the results of this study concluded that the ratio of Saccharomyces cerevisiae can affect the yield of virgin coconut oil produced. The preparation of virgin coconut oil enzymatically using a variety of mass ratio of 0.001 to 0.006% is obtained yield average of 12.40%. The optimum separation of virgin coconut oil on the use of enzymes with a mass ratio of 0.002%. The average water content at a ratio of 0.002% is 0.04 % with a value of uncertainty is 0.005%. The average iodine number in virgin coconut oil produced is 2.4403 ± 0,1974 grams of iodine per 100 grams of oil and optimum iodine number is obtained from the manufacturing process virgin coconut oil with a ratio of 0.006% Saccharomyces cerevisiae. Sacharomycescerevisiae with a ratio of 0.002% results virgin coconut oil with acid number 0.3068 ± 0.1098%. The peroxide value of virgin coconut oil between 0.0108 ± 0.009 to 0.0114 ± 0015milli-equivalent per kilograms. Organoleptic test results and test chemical parameters can be used as the test data that can be developed in prototype preparation of candidate in-house reference material in the testing standards of quality virgin coconut oil.

  4. Impedance study of the ion-to-electron transduction process for carbon cloth as solid-contact material in potentiometric ion sensors

    International Nuclear Information System (INIS)

    Mattinen, Ulriika; Rabiej, Sylwia; Lewenstam, Andrzej; Bobacka, Johan

    2011-01-01

    Carbon cloth was studied as solid-contact material in potentiometric ion sensors by using electrochemical impedance spectroscopy and potentiometry. The ion-to-electron transduction process was studied by electrochemical impedance spectroscopy by using a two-electrode symmetrical cell where a liquid electrolyte was sandwiched between two solid electrodes, including bare glassy carbon (GC), GC/carbon cloth and GC/poly(3,4-ethylenedioxythiophene). Impedance data for different electrode/electrolyte combinations were evaluated and compared. Solid-contact K + -selective electrodes were fabricated by coating the carbon cloth with a conventional plasticized PVC-based K + -selective membrane via drop casting. These K + -sensors showed proper analytical performance and acceptable long-term potential stability (potential drift ≈ 1 mV/day). Solid contact reference electrodes were fabricated in an analogous manner by coating the carbon cloth with a plasticized PVC membrane containing a moderately lipophilic salt. The results indicate that carbon cloth can be used as a solid-contact material in potentiometric ion sensors and pseudo-reference electrodes.

  5. The difference of 17% ethylenediaminetetraacetic acid irrigation material contact time of 60 seconds and 30 seconds toward of cleanliness of apical third root canal wall

    Directory of Open Access Journals (Sweden)

    Yunita Wijaya

    2011-11-01

    Full Text Available Root canal preparation is one important step in endodontic treatment, involves the cleaning and the shaping of the root canal debris. Root canal cleaning effectiveness depends on the preparation bio-mechanical and irrigation. Purpose of this study was to evaluate the cleanliness of apical third of root canal wall from of debris, with the contact time of 17% EDTA irrigation material for 60 seconds and 30 seconds after root canal preparation using rotary NiTi instruments. This quasi-experimental study was carried out invitro, with random sampling technique. The sample used was 20 central maxillary incisors that have been extracted and divided into two experimental groups of 10 teeth each. The results were analyzed using student t statistics, showed that the average value of the debris of the two groups differed significantly. The contact time of 60 seconds of 17% EDTA showed cleaner root canal than the 30 seconds. The conclusion of this study was there were the differences of the cleanliness of apical third of the root canal with the 60 seconds contact time of 17% EDTA irrigation materials than 30 seconds contact time.

  6. State of the art and challenges in development of electrical contact materials in the light of the RoHS directive

    Directory of Open Access Journals (Sweden)

    Ćosović V.

    2012-01-01

    Full Text Available The article surveys current state of the art and challenges in the development of the electrical contact materials in the light of the EU Directive on Restriction of Hazardous Substances (RoHS. The focus was placed on widely used silver-cadmium alloys. According to this directive, as of July 1, 2006, use of six hazardous materials, including cadmium, are restricted for applicable electrical and electronic products intended for the EU market. In contrast, traditionally preferred material for production of electrical contacts is Ag-CdO, due to its outstanding functional properties. These conflicting interests result in present state where RoHS directive has not yet been implemented in its original form and has undergone numerous amendments and exceptions regarding the use of cadmium. Main reason for this seems to be the unrealistic time frame imposed by legislation. Although, significant effort has been put into research and development of alternative materials, there are still cases where adequate replacement materials had not been found. Therefore, importance of synchronicity between legislation and technological progress i.e. communication between legislative administration and industry and academia is brought to light as well as some common issues that may arise with an introduction of new replacement materials or product modification. [Projekat Ministarstva nauke Republike SRbije, br. OI 172037 and TR 34023

  7. The influence of physical properties of materials used for slide rings on the process of heat transfer in the non-contacting face seals

    Directory of Open Access Journals (Sweden)

    Blasiak Slawomir

    2017-01-01

    Full Text Available The paper presents the results of analytical solution of the model of heat transfer for non-contacting face seals. Comparative analyses were performed for various physical properties of materials used for slide rings. A mathematical model includes a series of differential equations of partial derivatives with generally used boundary conditions, i.e. the Reynold’s equation, energy equation and heat transfer equations, which describe the heat transfer in sealing rings with surrounding medium. Heat transfer equation is written in the Cartesian coordinate system and solved using the Green’s functions method. Theoretical studies made it possible to draw a number of practical conclusions on the phenomena of heat transfer in the node seal. The presented model will allow more accurate identification of the heat transfer mechanism in the node seal. The results will help to select appropriate materials for sealing rings, depending on operating conditions of non-contacting face seals.

  8. Solder free joining as a highly effective method for making contact between thermoelectric materials and metallic electrodes

    DEFF Research Database (Denmark)

    Malik, Safdar Abbas; Le, Thanh Hung; Van Nong, Ngo

    2017-01-01

    /react with both Ag and Ni electrodes, and penetrate into ZnSb legs. SEM-EDX analysis recorded a significant excess of Zn in the ZnSb leg after joining. We found that, using microlayers of Ti and Cr as interconnecting agent, a very good interfacial contact was obtained, and the starting composition of ZnSb legs...

  9. Language Contact.

    Science.gov (United States)

    Nelde, Peter Hans

    1995-01-01

    Examines the phenomenon of language contact and recent trends in linguistic contact research, which focuses on language use, language users, and language spheres. Also discusses the role of linguistic and cultural conflicts in language contact situations. (13 references) (MDM)

  10. An analytical interpretation of the high temperature linear contact between composite materials reinforced with glass fibers and steel

    Science.gov (United States)

    Rus, Dorin; Florescu, Virgil; Bausic, Florin; Ursache, Robert; Sasu, Anca

    2018-01-01

    In this paper we have tried to present the influence of the metal surface wear and of the contact temperature on the evolution of the sliding speed, of the normal load and of the friction coefficient. We have performed numerous experimental trials that have highlighted the dependency between load and wear in relation to the friction coefficient. A dry linear friction couple was used with a large range of loads and speeds, simulating real-life working conditions: temperature, sliding speed, contact pressure. We have made a connection between the theoretical case and the experimental results arising from the use of the “wear imprint method” for the volume and depth of wear.

  11. Development of in-situ observation system of dynamic contact interface between dies and materials during microforming operation

    Directory of Open Access Journals (Sweden)

    Shimizu Tetsuhide

    2015-01-01

    Full Text Available Application of diamond like carbon (DLC films are reported in several microforming processes, in view of its great tribological performance owe to the low friction and the high chemical stability. However, due to its high internal residual stress, the film properties with the low adhesion strength and the high wear rate under severe tribological conditions are still remain as technical issues. However, since the dynamic variation of the contact state cannot be observed during the forming operation, it is difficult to recognize the origin and the influential tribological factors of tool life for DLC coated microforming die. Therefore, the appropriate DLC film properties for the contact state in microforming operation have not been clarified. To observe the dynamic variation of the contact state during the microforming operation, present study developed a novel microforming die assembly installed the in-situ observation system with silica glass die and high speed recording camera. By using this system, the dynamic delamination behaviour of DLC films during the progressive micro-bending process was successfully demonstrated. The influential factors for the durability of DLC coated microdies were discussed.

  12. Monitoring the restoration of interfacial contact for self healing thermal interface materials for LED and microelectronic applications

    NARCIS (Netherlands)

    Lafont, U.L.; Van Zeijl, H.W.; Van der Zwaag, S.

    2013-01-01

    While conventional self healing materials focus on the restoration of mechanical properties, newer generations of self healing materials focus on the restoration of other functional (i.e. non-mechanical) properties. Thermal conductivity is an example of an important functional property of a Thermal

  13. Exploring the sensitivity of the zone of inhibition test for leachable biocides from paper and board food contact materials, and improvements thereof.

    Science.gov (United States)

    Castle, L; Kelly, J; Jickells, S M; Johns, S M; Mountfort, K A

    2012-01-01

    The zone of inhibition method to test the release of biocides from paper and board food contact materials was evaluated. The method tests the paper by placing a small specimen directly onto culture plates of Bacillus subtilis and Aspergillus niger. The principle is that any extractable biocide will diffuse from the paper into the surrounding nutrient medium and so inhibit growth of the microorganism in the vicinity. The test was found to have insufficient sensitivity for assuring food safety, where detection limits for migration at or below the mg l(-1) (parts per million) level are needed. Also, the test does not mimic the actual or foreseeable conditions of use since most paper/board materials are not intended for direct contact with an aqueous medium for up to 3 days at 30°C (B. subtilis) or 25°C (A. niger), which are the incubation conditions used. The sensitivity of the test was increased approximately 100-fold by preparing a concentrated extract of the paper to be tested and applying this extract to the assay via a blank paper carrier. This was done using methanol as a good solvent for most biocides, as a proof of principle. Other solvents or food simulants could be used to mimic the conditions of use intended for the particular paper/board samples under examination, e.g. contact with dry, fatty, aqueous or acidic foods, hot or cold. Twenty-four plain (unconverted) paper and board samples and 100 food packaging samples were evaluated using the modified procedure. The results revealed that the method has been developed to the stage where background cytotoxic action of normal paper constituents gives a weak response. Unlike the original method, therefore, the modified method with its improved sensitivity and the facility to link with the intended food contact conditions may be considered a suitable bioassay screening test to complement chemical analysis of paper/board for composition and migration.

  14. Microbiological studies on drugs and their raw materials, 4. Sterilization of microbial contaminants in enzyme powder by gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, T; Yoshida, Y; Demura, H; Yanagita, T [Toyama Univ. (Japan). Faculty of Pharmaceutical Sciences; Meiwa, M

    1978-04-01

    The decimal reduction dose of ..gamma..-ray on freeze-dried clean Escherichia coli (E. coli) cells and Bacillus subtilis spores was about 7 x 10/sup 4/ rad and it was about three times higher than that on E. coli cells suspended in saline. E. coli cells contained in Takadiastase or trypsin powder showed quite the same susceptibility of ..gamma..-irradiation as they were present cleanly. These enzyme activities were not impaired at all even at the dose of 2 x 10/sup 5/ rad. When these enzyme powders containing E. coli cells were stored under varied atmospheric relative humidity, the deleterious effect of ..gamma..-ray on bacterial cells was highly enhanced in those samples stored under more than 80.5% relative humidities. The additions of excipients, such as glucose and lactose, and of a protectant, L-cysteine, to the bacteria-containing dry enzyme powder did not show any sign of either enhancement or retardation of ..gamma..-ray action on enzyme and bacteria. Based on these observations, the utilizability of radiosterilization on biological medicaments is discussed.

  15. Preparation of n-type Bi{sub 2}Te{sub 3} thermoelectric materials by non-contact dispenser printing combined with selective laser melting

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Keping; Yan, Yonggao; Zhang, Jian; Mao, Yu; Xie, Hongyao; Zhang, Qingjie; Tang, Xinfeng [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, Hubei (China); Yang, Jihui [Department of Materials Science and Engineering, University of Washington, Seattle, WA (United States); Uher, Ctirad [Department of Physics, University of Michigan, Ann Arbor, MI (United States)

    2017-06-15

    The manufacturing cost has been a bottle neck for broader applications of thermoelectric (TE) modules. We have developed a rapid, facile, and low cost method that combines non-contact dispenser printing with selective laser melting (SLM) and we demonstrate it on n-type Bi{sub 2}Te{sub 3}-based materials. Using this approach, single phase n-type Bi{sub 2}Te{sub 2.7}Se{sub 0.3} thin layers with the Seebeck coefficient of -152 μV K{sup -1} at 300 K have been prepared. Assembling such thin layers on top of each other, the performance of thus prepared bulk sample is comparable to Bi{sub 2}Te{sub 3}-based materials fabricated by the conventional techniques. Dispenser printing combined with SLM is a promising manufacturing process for TE materials. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Introduction to contact mechanics

    CERN Document Server

    Fischer-Cripps, Anthony C

    2000-01-01

    Contact mechanics deals with the elastic or plastic contact between two solid objects, and is thus intimately connected with such topics as fracture, hardness, and elasticity.This text, intended for advanced undergraduates, begins with an introduction to the mechanical properties of materials, general fracture mechanics, and fractures in brittle solids.This is followed by a detailed discussion of stresses and the nature of elastic and elastic-plastic contact.

  17. The effects of high-Dk rigid contact lens center thickness, material permeability, and blinking on the oxygen uptake of the human cornea.

    Science.gov (United States)

    Gardner, Hope Patterson; Fink, Barbara A; Mitchell, Lynn G; Hill, Richard M

    2005-06-01

    The human corneal oxygen uptake responses associated with the static (nonblinking) and dynamic (blinking) wear of five rigid gas-permeable materials with high oxygen permeabilities were determined for three different center thicknesses and compared with the responses for the normal open eye and severe hypoxic stress (static wear of polymethylmethacrylate). Corneal oxygen uptake rates were measured with a Clark-type polarographic electrode during two sessions with each of 10 human subjects. Measurements were made on the right eye for the normal open eye (air) and after 5 minutes of static and dynamic wear of polymethylmethacrylate and five rigid gas-permeable contact lens materials: Fluoroperm 92 (paflufocon A, Dk = 92), Fluoroperm 151 (paflufocon D, Dk = 151), 1992 Menicon SF-P (melafocon A, Dk = 102), 1995 Menicon SF-P (melafocon A, Dk = 159), and Menicon Z (tisilfocon A, Dk = 163-250). Lenses were manufactured in three different center thicknesses (0.12, 0.16, and 0.20 mm), with all other parameters remaining constant. Repeated-measures analysis of variance was used and included lens material (five levels), blinking condition (two levels), and lens thickness (three levels) as within-subject effects. Significant differences were found in corneal oxygen responses to lens material (p Dk rigid lens materials studied here, moderate changes in lens thickness or material permeability may result in modest differences in corneal hypoxic relief, whereas blinking results in no significant improvement to corneal oxygenation.

  18. Optimization of mass spectrometry acquisition parameters for determination of polycarbonate additives, degradation products, and colorants migrating from food contact materials to chocolate.

    Science.gov (United States)

    Bignardi, Chiara; Cavazza, Antonella; Laganà, Carmen; Salvadeo, Paola; Corradini, Claudio

    2018-01-01

    The interest towards "substances of emerging concerns" referred to objects intended to come into contact with food is recently growing. Such substances can be found in traces in simulants and in food products put in contact with plastic materials. In this context, it is important to set up analytical systems characterized by high sensitivity and to improve detection parameters to enhance signals. This work was aimed at optimizing a method based on UHPLC coupled to high resolution mass spectrometry to quantify the most common plastic additives, and able to detect the presence of polymers degradation products and coloring agents migrating from plastic re-usable containers. The optimization of mass spectrometric parameter settings for quantitative analysis of additives has been achieved by a chemometric approach, using a full factorial and d-optimal experimental designs, allowing to evaluate possible interactions between the investigated parameters. Results showed that the optimized method was characterized by improved features in terms of sensitivity respect to existing methods and was successfully applied to the analysis of a complex model food system such as chocolate put in contact with 14 polycarbonate tableware samples. A new procedure for sample pre-treatment was carried out and validated, showing high reliability. Results reported, for the first time, the presence of several molecules migrating to chocolate, in particular belonging to plastic additives, such Cyasorb UV5411, Tinuvin 234, Uvitex OB, and oligomers, whose amount was found to be correlated to age and degree of damage of the containers. Copyright © 2017 John Wiley & Sons, Ltd.

  19. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... videos on your website Promotional materials for eye health observances EyeSmart resources are also available in Spanish . Follow The Academy Professionals: Education Guidelines News Multimedia Public & Patients: Contact Us About the Academy Jobs at ...

  20. Nano-enhanced food contact materials and the in vitro toxicity to human intestinal cells of nano-ZnO at low dose

    International Nuclear Information System (INIS)

    Claonadh, Niall O; Casey, Alan; Mukherjee, Sanchali Gupta; Chambers, Gordon; Lyons, Sean; Higginbotham, Clement

    2011-01-01

    Nano Zinc Oxide (nZnO) has been shown to display antimicrobial effects which have lead to its application in a number of areas such as antimicrobial surface coatings, anti bacterial wound dressings and more recently in polymer composite systems for use in food contact materials. Concerns have been raised due to the incorporation of nanoparticles in food packaging stemming from the possibility of repeated low dose direct exposure, through ingestion, primarily due to degradation and nanoparticle leaching from the polymer composite. To address these concerns, composites consisting of nZnO and polyethylene were formed using twin screw extrusion to mimic commercial methods of food contact material production. A leaching study was performed using Atomic Absorption Spectroscopy in order to determine the concentration of nZnO leached from the composite. Composite stability studies were performed and a leached nZnO concentration was evaluated. This concentration range was then utilised in a series of tests aimed at determining the toxicity response associated with nZnO when exposed to an intestinal model. In this study two human colorectal carcinoma cell lines, HT29 (ATCC No: HTB-38) and SW480 (ATTC No: CCL-228), were employed as a model to represent areas exposed by ingestion. These lines were exposed to a concentration range of nZnO which incorporated the concentration leached from the composites. The cytotoxic effects of nZnO were evaluated using four cytotoxic endpoints namely the Neutral Red, Alamar Blue, Coomassie Blue and MTT assays. The results of these studies are presented and their implications for the use on nano ZnO in direct food contact surfaces will be discussed.

  1. Nano-enhanced food contact materials and the in vitro toxicity to human intestinal cells of nano-ZnO at low dose

    Energy Technology Data Exchange (ETDEWEB)

    Claonadh, Niall O; Casey, Alan; Mukherjee, Sanchali Gupta; Chambers, Gordon [Nanolab Research Centre, Focas Institute, Dublin Institute of Technology, Dublin (Ireland); Lyons, Sean; Higginbotham, Clement, E-mail: Niall.OClaonadh@DIT.ie, E-mail: Alan.Casey@DIT.ie [Materials Research Institute, Athlone Institute of Technology, Westmeath (Ireland)

    2011-07-06

    Nano Zinc Oxide (nZnO) has been shown to display antimicrobial effects which have lead to its application in a number of areas such as antimicrobial surface coatings, anti bacterial wound dressings and more recently in polymer composite systems for use in food contact materials. Concerns have been raised due to the incorporation of nanoparticles in food packaging stemming from the possibility of repeated low dose direct exposure, through ingestion, primarily due to degradation and nanoparticle leaching from the polymer composite. To address these concerns, composites consisting of nZnO and polyethylene were formed using twin screw extrusion to mimic commercial methods of food contact material production. A leaching study was performed using Atomic Absorption Spectroscopy in order to determine the concentration of nZnO leached from the composite. Composite stability studies were performed and a leached nZnO concentration was evaluated. This concentration range was then utilised in a series of tests aimed at determining the toxicity response associated with nZnO when exposed to an intestinal model. In this study two human colorectal carcinoma cell lines, HT29 (ATCC No: HTB-38) and SW480 (ATTC No: CCL-228), were employed as a model to represent areas exposed by ingestion. These lines were exposed to a concentration range of nZnO which incorporated the concentration leached from the composites. The cytotoxic effects of nZnO were evaluated using four cytotoxic endpoints namely the Neutral Red, Alamar Blue, Coomassie Blue and MTT assays. The results of these studies are presented and their implications for the use on nano ZnO in direct food contact surfaces will be discussed.

  2. Overall and specific migration from multilayer high barrier food contact materials - kinetic study of cyclic polyester oligomers migration.

    Science.gov (United States)

    Úbeda, Sara; Aznar, Margarita; Vera, Paula; Nerín, Cristina; Henríquez, Luis; Taborda, Laura; Restrepo, Claudia

    2017-10-01

    Most multilayer high barrier materials used in food packaging have a polyurethane adhesive layer in their structures. In order to assess the safety of these materials, it is important to determine the compounds intentionally added to the adhesives (IAS) as well as those non-intentionally added substances (NIAS). During the manufacture of polyurethane adhesives, some by-products can be formed, such as cyclic polyester oligomers coming from the reaction between dicarboxylic acids and glycols. Since these compounds are not listed in the Regulation 10/2011/EU, they should not be found in migration above 0.01 mg/kg of simulant. In this study two flexible multilayer packaging materials were used and migration was evaluated in simulant A (ethanol 10% v/v), simulant B (acetic acid 3% w/v) and simulant ethanol 95% v/v during 10 days at 60ºC. Identification and quantification of non-volatile compounds was carried out by UPLC-MS-QTOF. Most of migrants were oligomers such as cyclic polyesters and caprolactam oligomers. Overall migration and specific migration of adipic acid-diethylene glycol and phthalic acid-diethylene glycol were monitored over time and analysed by UPLC-MS-TQ. In most cases, ethanol 95% v/v was the simulant with the highest concentration values. Overall migration kinetics followed a similar pattern than specific migration kinetics.

  3. Effects of Material Combinations on Friction and Wear of PEEK/Steel Pairs under Oil-Lubricated Sliding Contacts

    Science.gov (United States)

    Akagaki, T.; Nakamura, T.; Hashimoto, Y.; Kawabata, M.

    2017-05-01

    The effects of material combinations on the friction and wear of PEEK/steel pairs are studied using blocks on a ring wear tester under oil-lubricated conditions. The rings are made of forged steel (SF540A) and a PEEK composite filled with 30 wt% carbon fibre. The surface roughness is 0.15 and 0.32 μm Ra, respectively. The blocks are also made of the same materials as the rings: the forged steel and the PEEK composite. Finished with an emery paper of #600, the surface roughness is 0.06 and 0.23 μm Ra, respectively. Sliding tests for 4 combinations of two materials are conducted. The load is increased up to 1177 N at 1 N s-1. The sliding velocity is varied in the range of 10 to 19 m s-1. In some cases, the ring temperature is measured with a thermocouple with a diameter of 0.5 mm, located 1 mm below the frictional surface. Results indicate that the forged steel’s ring and the PEEK composite’s block is the best combination among 4 combinations, because seizure does not occur under the increasing load up to 1177 N at the sliding velocity of 10-19 m s-1. In contrast, seizure occurs at 15 and 19 m s-1 in the other three combinations. However, the PEEK composite’s ring shows a lower friction coefficient as compared to the forged steel’s ring, when seizure does not occur. Wear scars are observed with a scanning electron microscope (SEM). The seizure mechanisms are then discussed.

  4. Electrical contacts principles and applications

    CERN Document Server

    Slade, Paul G

    2013-01-01

    Covering the theory, application, and testing of contact materials, Electrical Contacts: Principles and Applications, Second Edition introduces a thorough discussion on making electric contact and contact interface conduction; presents a general outline of, and measurement techniques for, important corrosion mechanisms; considers the results of contact wear when plug-in connections are made and broken; investigates the effect of thin noble metal plating on electronic connections; and relates crucial considerations for making high- and low-power contact joints. It examines contact use in switch

  5. Uterotrophic and Hershberger assays for endocrine disruption properties of plastic food contact materials polypropylene (PP) and polyethylene terephthalate (PET).

    Science.gov (United States)

    Chung, Bu Young; Kyung, Minji; Lim, Seong Kwang; Choi, Seul Min; Lim, Duck Soo; Kwack, Seung Jun; Kim, Hyung Sik; Lee, Byung-Mu

    2013-01-01

    Plasticizers or plastic materials such as phthalates, bisphenol-A (BPA), and styrene are widely used in the plastic industry and are suspected endocrine-disrupting chemicals (EDC). Although plastic materials such as polypropylene (PP) and polyethylene terephthalate (PET) are not EDC and are considered to be safe, their potential properties as EDC have not been fully investigated. In this study, plastic samples eluted from plastic food containers (PP or PET) were investigated in Sprague-Dawley rats using Hershberger and uterotrophic assays. In the Hershberger assay, 6-wk-old castrated male rats were orally treated for 10 consecutive days with plastic effluent at 3 different doses (5 ml/kg) or vehicle control (corn oil, 1 ml/100 g) to determine the presence of both anti-androgenic and androgenic effects. Testosterone (0.4 mg/ml/kg) was subcutaneously administered for androgenic evaluation as a positive control, whereas testosterone (0.4 mg/ml/kg) and flutamide (3 mg/kg/day) were administered to a positive control group for anti-androgenic evaluation. The presence of any anti-androgenic or androgenic activities of plastic effluent was not detected. Sex accessory tissues such as ventral prostate or seminal vesicle showed no significant differences in weight between treated and control groups. For the uterotrophic assay, immature female rats were treated with plastic effluent at three different doses (5 ml/kg), with vehicle control (corn oil, 1 ml/100 g), or with ethinyl estradiol (3 μg/kg/d) for 3 d. There were no significant differences between test and control groups in vagina or uterine weight. Data suggest that effluents from plastic food containers do not appear to produce significant adverse effects according to Hershberger and uterotrophic assays.

  6. Non-targeted screening for contaminants in paper and board food-contact materials using effect-directed analysis and accurate mass spectrometry

    DEFF Research Database (Denmark)

    Bengtström, Linda; Rosenmai, Anna Kjerstine; Trier, Xenia

    2016-01-01

    Due to large knowledge gaps in chemical composition and toxicological data for substances involved, paper and board food-contact materials (P&B FCM) have been emerging as a FCM type of particular concern for consumer safety. This study describes the development of a step-by-step strategy, including......R) activity. These fractions were analysed by gas chromatography (GC) and ultra-HPLC (UHPLC) coupled to quadrupole time-of-flight mass spectrometers (QTOF MS) in order tentatively to identify substances. The elemental composition was determined for peaks above a threshold, and compared with entries...... in a commercial mass spectral library for GC-MS (GC-EI-QTOF MS) analysis and an in-house built library of accurate masses for substances known to be used in P&B packaging for UHPLC-QTOF analysis. Of 75 tentatively identified substances, 15 were initially selected for further testing in vitro; however, only seven...

  7. Overproduction of ligninolytic enzymes

    Science.gov (United States)

    Elisashvili, Vladimir; Kachlishvili, Eva; Torok, Tamas

    2014-06-17

    Methods, compositions, and systems for overproducing ligninolytic enzymes from the basidiomycetous fungus are described herein. As described, the method can include incubating a fungal strain of Cerrena unicolor IBB 303 in a fermentation system having growth medium which includes lignocellulosic material and then cultivating the fungal strain in the fermentation system under conditions wherein the fungus expresses the ligninolytic enzymes. In some cases, the lignocellulosic material is mandarin peel, ethanol production residue, walnut pericarp, wheat bran, wheat straw, or banana peel.

  8. Conversion and degradation of shellfish wastes by Serratia sp. TKU016 fermentation for the production of enzymes and bioactive materials.

    Science.gov (United States)

    Wang, San-Lang; Chang, Tao-Jen; Liang, Tzu-Wen

    2010-06-01

    A chitosanase and a protease were purified from the culture supernatant of Serratia sp. TKU016 with shrimp shell as the sole carbon/nitrogen source. The molecular masses of the chitosanase and protease determined by SDS-PAGE were approximately 65 and 53 kDa, respectively. The chitosanase was inhibited completely by Mn2+, but the protease was enhanced by all of tested divalent metals. The optimum pH, optimum temperature, pH stability, and thermal stability of the chitosanase and protease were (pH 7, 50 degrees C, pH 6-7, <50 degrees C) and (pH 8-10, 40 degrees C, pH 5-10, <50 degrees C), respectively. SDS (2 mM) had stimulatory effect on TKU016 protease activity. The result demonstrates that TKU016 protease is SDS-resistant protease and probably has a rigid structure. Besides, TKU016 culture supernatant (2% SPP) incubated for 2 days has the highest antioxidant activity, the DPPH scavenging ability was about 76%. With this method, we have shown that shrimp shell wastes can be utilized and it's effective in the production of enzymes, antioxidants, peptide and reducing sugar, facilitating its potential use in biological applications and functional foods.

  9. Contact activation: a revision.

    Science.gov (United States)

    Schmaier, A H

    1997-07-01

    In conclusion, a revised view of the contact system has been presented. This system has little to do with the initiation of hemostasis. Like lupus anticoagulants, deficiencies of contact proteins give prolonged APTTs but may be risk factors for thrombosis. BK from kininogens is a potent modulator of vascular biology inducing vasodilation, tissue plasminogen activator release, and prostacyclin liberation. Kininogens, themselves, are selective inhibitors of alpha-thrombin-induced platelet activation preventing alpha-thrombin from cleaving the cloned thrombin receptor after arginine41. Kininogens' alpha-thrombin inhibitory activity exists in intact kininogens, BK, and all of BK's breakdown products. HK also is the pivotal protein for contact protein assembly on endothelium. It is the receptor for prekallikrein which when bound to HK becomes activated to kallikrein by an endothelial cell enzyme system independent of activated forms of plasma factor XII. Prekallikrein activation on endothelial cells results in kinetically favorable single chain urokinase and plasminogen activation. Thus the "physiologic, negatively charged surface" for contact system activation is really the assembly of these proteins on cell membranes and activation by membrane-associated enzymes.

  10. Termite enzymes and uses thereof for in vitro conversion of lignin-containing materials to fermentable products

    Science.gov (United States)

    Scharf, Michael E; Boucias, Drion G; Tartar, Aurelien; Coy, Monique R; Zhou, Xuguo; Salem, Tamer Ibrahim Zaki; Jadhao, Sanjay B; Wheeler, Marsha M

    2013-05-21

    The disclosure provides isolated nucleic acid molecules derived from the gut of the termite R flavipes, recombinant nucleic acid molecules comprising a vector and an isolated heterologous nucleic acid molecule operably inserted therein, whereby, when transformed into an appropriate host cell system, the heterologous nucleic acid sequence is expressed as a polypeptide having an activity similar to that when expressed in the gut of the termite R. flavipes. The recombinant nucleic acid molecules can comprise more than one heterologous nucleic acid molecule such that more than one polypeptide may be expressed by the host system. The expressed polypeptides may be substantially purified, or used in a substantially unpurified form, to be admixed with a lignocellulose source to be converted to a fermentable product such as a sugar or a mixture of sugars. One aspect of the present disclosure, therefore, encompasses methods of converting a lignified plant material to a fermentable product, the method comprising obtaining a series of isolated polypeptides of a termite, wherein the series of polypeptides cooperate to convert a plant lignocellulose to a fermentable product; and incubating the series of polypeptides with a source of lignified plant material, under conditions allowing the polypeptides to cooperatively produce a fermentable product from the lignified plant material.

  11. The surface science of enzymes

    DEFF Research Database (Denmark)

    Rod, Thomas Holm; Nørskov, Jens Kehlet

    2002-01-01

    One of the largest challenges to science in the coming years is to find the relation between enzyme structure and function. Can we predict which reactions an enzyme catalyzes from knowledge of its structure-or from its amino acid sequence? Can we use that knowledge to modify enzyme function......? To solve these problems we must understand in some detail how enzymes interact with reactants from its surroundings. These interactions take place at the surface of the enzyme and the question of enzyme function can be viewed as the surface science of enzymes. In this article we discuss how to describe...... catalysis by enzymes, and in particular the analogies between enzyme catalyzed reactions and surface catalyzed reactions. We do this by discussing two concrete examples of reactions catalyzed both in nature (by enzymes) and in industrial reactors (by inorganic materials), and show that although analogies...

  12. Tribological Characteristics of C/C-SiC-Cu Composite and Al/SiC Composite Materials under Various Contact Conditions

    International Nuclear Information System (INIS)

    Kim, Byung-Kook; Shin, Dong-Gap; Kim, Chang-Lae; Kim, Dae-Eun; Goo, Byeong-Choon

    2017-01-01

    The surface temperature of disc brakes varies during braking, which can affect the friction and wear behavior of braking systems. In order to develop an efficient braking system, the friction and wear behaviors of brake materials need to be clearly understood. In this work, the friction and wear behavior of the C/C-SiC-Cu composite and the Al/SiC composite, which are used in disc braking systems, were investigated. Both the surface temperature and contact pressure were studied. A pin-on-reciprocating tribotester was used for this purpose, in order to control temperature and load. Results showed that the friction varied significantly with temperature and sliding distance. It was found that a transfer layer of compacted wear debris formed on the wear track of the two materials. These layers caused the surface roughness of the wear track to increase. The outcome of this work is expected to serve as a basis for the development of braking systems under various operating conditions.

  13. Tribological Characteristics of C/C-SiC-Cu Composite and Al/SiC Composite Materials under Various Contact Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Byung-Kook; Shin, Dong-Gap; Kim, Chang-Lae; Kim, Dae-Eun [Yonsei Univ., Seoul (Korea, Republic of); Goo, Byeong-Choon [Korea Railroad Research Institute, Uiwang (Korea, Republic of)

    2017-01-15

    The surface temperature of disc brakes varies during braking, which can affect the friction and wear behavior of braking systems. In order to develop an efficient braking system, the friction and wear behaviors of brake materials need to be clearly understood. In this work, the friction and wear behavior of the C/C-SiC-Cu composite and the Al/SiC composite, which are used in disc braking systems, were investigated. Both the surface temperature and contact pressure were studied. A pin-on-reciprocating tribotester was used for this purpose, in order to control temperature and load. Results showed that the friction varied significantly with temperature and sliding distance. It was found that a transfer layer of compacted wear debris formed on the wear track of the two materials. These layers caused the surface roughness of the wear track to increase. The outcome of this work is expected to serve as a basis for the development of braking systems under various operating conditions.

  14. Contacts to semiconductors

    International Nuclear Information System (INIS)

    Tove, P.A.

    1975-08-01

    Contacts to semiconductors play an important role in most semiconductor devices. These devices range from microelectronics to power components, from high-sensitivity light or radiation detectors to light-emitting of microwave-generating components. Silicon is the dominating material but compound semiconductors are increasing in importance. The following survey is an attempt to classify contact properties and the physical mechanisms involved, as well as fabrication methods and methods of investigation. The main interest is in metal-semiconductor type contacts where a few basic concepts are dealt with in some detail. (Auth.)

  15. Influence of interfacial layer on contact resistance

    NARCIS (Netherlands)

    Roy, D.; In 't Zand, M.A.A.; Delhounge, R.; Klootwijk, J.H.; Wolters, Robertus A.M.

    2008-01-01

    The contact resistance between two materials is dependent on the intrinsic properties of the materials in contact and the presence and properties of an interfacial layer at the contact. This article presents the difference in contact resistance measurements with and without the presence of a process

  16. Evaluating the effects of bedding materials and elevated platforms on contact dermatitis and plumage cleanliness of commercial broilers and on litter condition in broiler houses.

    Science.gov (United States)

    Kaukonen, E; Norring, M; Valros, A

    2017-10-01

    1. Experiment 1, comparing wood shavings and ground straw bedding with peat, was performed on 7 broiler farms over two consecutive batches during the winter season. Experiment 2, assessing the effect of elevated (30 cm) platforms, was conducted in three farms replicated with 6 consecutive batches. 2. Footpad lesions were inspected at slaughter following the Welfare Quality® (WQ) assessment and official programme. Hock lesions, plumage cleanliness and litter condition were assessed using the WQ assessment. Litter height, pH, moisture and ammonia were determined. 3. Footpad condition on wood shavings appeared to be worse compared with peat using both methods of assessment and was accompanied by inferior hock skin health. WQ assessment resulted in poorer footpad and hock skin condition on ground straw compared with peat. Farms differed in footpad and hock skin condition. Footpad and hock lesions were not affected by platform treatment. Peat appeared more friable than ground straw. The initial pH of wood shavings was higher and moisture was lower than in peat, but at the end of production period there were no differences. Ground straw exhibited higher initial and lower end pH, and was drier in the beginning than peat. Litter condition and quality were not affected by platform treatment. 4. This study provides new knowledge about the applicability of peat as broiler bedding and shows no negative effects of elevated platforms on litter condition or the occurrence of contact dermatitis in commercial environments. The results suggest a complicated relationship between litter condition, moisture and contact dermatitis. Furthermore, it is concluded that the farmer's ability to manage litter conditions is important, regardless of the chosen litter material. Peat bedding was beneficial for footpad and hock skin health compared with wood shavings and ground straw.

  17. Enzyme Informatics

    Science.gov (United States)

    Alderson, Rosanna G.; Ferrari, Luna De; Mavridis, Lazaros; McDonagh, James L.; Mitchell, John B. O.; Nath, Neetika

    2012-01-01

    Over the last 50 years, sequencing, structural biology and bioinformatics have completely revolutionised biomolecular science, with millions of sequences and tens of thousands of three dimensional structures becoming available. The bioinformatics of enzymes is well served by, mostly free, online databases. BRENDA describes the chemistry, substrate specificity, kinetics, preparation and biological sources of enzymes, while KEGG is valuable for understanding enzymes and metabolic pathways. EzCatDB, SFLD and MACiE are key repositories for data on the chemical mechanisms by which enzymes operate. At the current rate of genome sequencing and manual annotation, human curation will never finish the functional annotation of the ever-expanding list of known enzymes. Hence there is an increasing need for automated annotation, though it is not yet widespread for enzyme data. In contrast, functional ontologies such as the Gene Ontology already profit from automation. Despite our growing understanding of enzyme structure and dynamics, we are only beginning to be able to design novel enzymes. One can now begin to trace the functional evolution of enzymes using phylogenetics. The ability of enzymes to perform secondary functions, albeit relatively inefficiently, gives clues as to how enzyme function evolves. Substrate promiscuity in enzymes is one example of imperfect specificity in protein-ligand interactions. Similarly, most drugs bind to more than one protein target. This may sometimes result in helpful polypharmacology as a drug modulates plural targets, but also often leads to adverse side-effects. Many cheminformatics approaches can be used to model the interactions between druglike molecules and proteins in silico. We can even use quantum chemical techniques like DFT and QM/MM to compute the structural and energetic course of enzyme catalysed chemical reaction mechanisms, including a full description of bond making and breaking. PMID:23116471

  18. Plasma membrane—endoplasmic reticulum contact sites regulate phosphatidylcholine synthesis

    NARCIS (Netherlands)

    Tavassoli, S.; Chao, J.T.; Young, B.P.; Cox, R.C.; Prinz, W.A.; de Kroon, A.I.P.M.; Loewen, C.I.R.

    2013-01-01

    Synthesis of phospholipids, sterols and sphingolipids is thought to occur at contact sites between the endoplasmic reticulum (ER) and other organelles because many lipid-synthesizing enzymes are enriched in these contacts. In only a few cases have the enzymes been localized to contacts in vivo and

  19. Analytical, Numerical, and Experimental Investigation on a Non-Contact Method for the Measurements of Creep Properties of Ultra-High-Temperature Materials

    Science.gov (United States)

    Lee, Jonghyun; Hyers, Robert W.; Rogers, Jan R.; Rathz, Thomas J.; Choo, Hahn; Liaw, Peter

    2006-01-01

    Responsive access to space requires re-use of components such as rocket nozzles that operate at extremely high temperatures. For such applications, new ultra-hightemperature materials that can operate over 2,000 C are required. At the temperatures higher than the fifty percent of the melting temperature, the characterization of creep properties is indispensable. Since conventional methods for the measurement of creep is limited below 1,700 C, a new technique that can be applied at higher temperatures is strongly demanded. This research develops a non-contact method for the measurement of creep at the temperatures over 2,300 C. Using the electrostatic levitator in NASA MSFC, a spherical sample was rotated to cause creep deformation by centrifugal acceleration. The deforming sample was captured with a digital camera and analyzed to measure creep deformation. Numerical and analytical analyses have also been conducted to compare the experimental results. Analytical, numerical, and experimental results showed a good agreement with one another.

  20. Lente de contato de material híbrido em pacientes com ceratocone e astigmatismo miópico composto Hybrid material contact lens in keratoconus and myopic astigmatism patients

    Directory of Open Access Journals (Sweden)

    Fernando Leal

    2007-03-01

    óculos, exceto para a freqüência B (3 cpg, maior nos usuários de óculos. As aberrações de alta ordem analisadas apresentaram diminuição estatisticamente significante, quando comparados os pacientes sem e com uso de lentes de contato, com exceção da aberração esférica e do coma. CONCLUSÃO: A lente de contato de material híbrido, quando utilizada por portadores de ceratocone e astigmatismo miópico composto, propiciaram desempenho visual e conforto satisfatórios, em níveis que não diferiram, das lentes de contato rígidas-gás-permeáveis nos dois grupos de pacientes.PURPOSE: To evaluate comfort and visual performance in relation to two different used contact lens types: hybrid material (HM and rigid-gas-permeable (RGP, in patients with regular myopic astigmatism and with keratoconus. METHODS: A randomized, double masked, prospective study of 22 patients with the diagnosis of myopic astigmatism (8 with myopic astigmatism and 14 with keratoconus was conducted. Fifteen patients were female and 7 were male, and mean age was: 32.13 ± 8.12 years. In one of the eyes a rigid-gas-permeable contact lens was adapted (DK 30, and in the other a hybrid material contact lens was adapted (DK 23. All patients were submitted to the following tests: measurement of comfort level by means of the analogical visual scale, tear break-up time, best corrected visual acuity with the Bailey-Lovie scale adapted for 4 meters, functional acuity contrast test (FACT and wavefront analysis. RESULTS: In relation to comfort, there was no association with the evaluated contact lens type (p=0.350. There was a variation in comfort level during the first 7 days. The visual acuity increased between the 7th and the 15th day of adaptation. Visual acuity stabilized right after this period. The visual acuity did not show differences in relation to the studied lens type. It was verified that there was no difference in the tear break-up time (p=0.989 in relation to the studied lenses type and

  1. LANL Contacts

    Science.gov (United States)

    : (505) 665-3664 ethics@lanl.gov Journalist queries Communications Office (505) 667-7000 Media contacts programs and employee resources. General Employee directory Emergency communication Communications Office (505) 667-7000 Ethics & Audits Internal Audit: (505) 665-3104 Ethics Office: (505) 667-7506 Fax

  2. Investigation of a Spinel-forming Cu-Mn Foam as an Oxygen Electrode Contact Material in a Solid Oxide Cell Single Repeating Unit

    DEFF Research Database (Denmark)

    Zielke, Philipp; Wulff, Anders Christian; Sun, Xiufu

    2017-01-01

    A critical issue in state-of-the-art solid oxide cell stacks is the contacting of the oxygen electrode. The commonly used ceramic contact layers are applied in a green state and cannot be sintered properly, due to compliance limitations arising from other stack components like sealing glasses...

  3. Contact activation of blood-plasma coagulation

    Science.gov (United States)

    Golas, Avantika

    Surface engineering of biomaterials with improved hemocompatibility is an imperative, given the widespread global need for cardiovascular devices. Research summarized in this dissertation focuses on contact activation of FXII in buffer and blood plasma frequently referred to as autoactivation. The extant theory of contact activation imparts FXII autoactivation ability to negatively charged, hydrophilic surfaces. According to this theory, contact activation of plasma involves assembly of proteins comprising an "activation complex" on activating surfaces mediated by specific chemical interactions between complex proteins and the surface. This work has made key discoveries that significantly improve our core understanding of contact activation and unravel the existing paradigm of plasma coagulation. It is shown herein that contact activation of blood factor XII (FXII, Hageman factor) in neat-buffer solution exhibits a parabolic profile when scaled as a function of silanized-glass-particle activator surface energy (measured as advancing water adhesion tension t°a=g° Iv costheta in dyne/cm, where g°Iv is water interfacial tension in dyne/cm and theta is the advancing contact angle). Nearly equal activation is observed at the extremes of activator water-wetting properties --36 moderated by adsorption of plasma proteins unrelated to coagulation through an "adsorption-dilution" effect that blocks FXII contact with hydrophobic activator surfaces. The adsorption-dilution effect explains the apparent specificity for hydrophilic activators pursued by earlier investigators. Finally a comparison of FXII autoactivation in buffer, serum, protein cocktail, and plasma solutions is shown herein. Activation of blood plasma coagulation in vitro by contact with material surfaces is demonstrably dependent on plasma-volume-to-activator-surface-area ratio. However, activation of factor XII dissolved in buffer, protein cocktail, heat-denatured serum, and FXI deficient plasma does not

  4. Emission of perfluoroalkyl carboxylic acids (PFCA) from heated surfaces made of polytetrafluoroethylene (PTFE) applied in food contact materials and consumer products.

    Science.gov (United States)

    Schlummer, Martin; Sölch, Christina; Meisel, Theresa; Still, Mona; Gruber, Ludwig; Wolz, Gerd

    2015-06-01

    Polytetrafluoroethylene (PTFE) has been widely discussed as a source of perfluorooctanoic acid (PFOA), which has been used in the production of fluoropolymers. PTFE may also contain unintended perfluoroalkyl carboxylic acids (PFCAs) caused by thermolysis of PTFE, which has been observed at temperatures above 300°C. Common PTFE coated food contact materials and consumer goods are operated at temperatures above 200°C. However, knowledge on possible emissions of PFCAs is limited. Therefore, it was the aim of this study to investigate and evaluate the emission of PFCAs from PTFE coated products with both, normal use and overheating scenarios. Four pans, claimed to be PFOA free, and nine consumer products were investigated. At normal use conditions (PTFE surfaces were trapped for 1h. Overheating scenarios (>260°C) recorded emissions during a 30min heating of empty pans on a stove. Emissions were analyzed by LC-ESI-MS. Results indicate the emission of PFCAs, whereas no perfluorinated sulfonic acids were traced. At normal use conditions total emissions of PFCAs accounted for 4.75ng per hour. Overheated pans, however, released far higher amounts with up to 12190ng PFCAs per hour at 370°C. Dominating contributors where PFBA and PFOA at normal use and PFBA and PFPeA during overheating. Temperature seems to be the main factor controlling the emission of PFCAs. A worst case estimation of human exposure revealed that emissions of PFCAs from heated PTFE surfaces would be far below the TDI of 1500ng PFOA per kg body weight. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Endocrine disrupting chemicals and other substances of concern in food contact materials: an updated review of exposure, effect and risk assessment.

    Science.gov (United States)

    Muncke, Jane

    2011-10-01

    Food contact materials (FCM) are an underestimated source of chemical food contaminants and a potentially relevant route of human exposure to endocrine disrupting chemicals (EDCs). Quantifying the exposure of the general population to substances from FCM relies on estimates of food consumption and leaching into food. Recent studies using polycarbonate plastics show that food simulants do not always predict worst-case leaching of bisphenol A, a common FCM substance. Also, exposure of children to FCM substances is not always realistically predicted using the common conventions and thus possibly misjudged. Further, the exposure of the whole population to substances leaching into dry foods is underestimated. Consumers are exposed to low levels of substances from FCM across their entire lives. Effects of these compounds currently are assessed with a focus on mutagenicity and genotoxicity. This approach however neglects integrating recent new toxicological findings, like endocrine disruption, mixture toxicity, and developmental toxicity. According to these new toxicology paradigms women of childbearing age and during pregnancy are a new sensitive population group requiring more attention. Furthermore, in overweight and obese persons a change in the metabolism of xenobiotics is observed, possibly implying that this group of consumers is insufficiently protected by current risk assessment practice. Innovations in FCM risk assessment should therefore include routine testing for EDCs and an assessment of the whole migrate toxicity of a food packaging, taking into account all sensitive population groups. In this article I focus on recent issues of interest concerning either exposure to or effects of FCM-related substances. Further, I review the use of benzophenones and organotins, two groups of known or suspected EDCs, in FCM authorized in the US and EU. Copyright © 2010 Elsevier Ltd. All rights reserved.

  6. Non-targeted screening for contaminants in paper and board food-contact materials using effect-directed analysis and accurate mass spectrometry.

    Science.gov (United States)

    Bengtström, Linda; Rosenmai, Anna Kjerstine; Trier, Xenia; Jensen, Lisbeth Krüger; Granby, Kit; Vinggaard, Anne Marie; Driffield, Malcolm; Højslev Petersen, Jens

    2016-06-01

    Due to large knowledge gaps in chemical composition and toxicological data for substances involved, paper and board food-contact materials (P&B FCM) have been emerging as a FCM type of particular concern for consumer safety. This study describes the development of a step-by-step strategy, including extraction, high-performance liquid chromatography (HPLC) fractionation, tentative identification of relevant substances and in vitro testing of selected tentatively identified substances. As a case study, we used two fractions from a recycled pizza box sample which exhibited aryl hydrocarbon receptor (AhR) activity. These fractions were analysed by gas chromatography (GC) and ultra-HPLC (UHPLC) coupled to quadrupole time-of-flight mass spectrometers (QTOF MS) in order tentatively to identify substances. The elemental composition was determined for peaks above a threshold, and compared with entries in a commercial mass spectral library for GC-MS (GC-EI-QTOF MS) analysis and an in-house built library of accurate masses for substances known to be used in P&B packaging for UHPLC-QTOF analysis. Of 75 tentatively identified substances, 15 were initially selected for further testing in vitro; however, only seven were commercially available and subsequently tested in vitro and quantified. Of these seven, the identities of three pigments found in printing inks were confirmed by UHPLC tandem mass spectrometry (QqQ MS/MS). Two pigments had entries in the database, meaning that a material relevant accurate mass database can provide a fast tentative identification. Pure standards of the seven tentatively identified substances were tested in vitro but could not explain a significant proportion of the AhR-response in the extract. Targeted analyses of dioxins and PCBs, both well-known AhR agonists, was performed. However, the dioxins could explain approximately 3% of the activity observed in the pizza box extract indicating that some very AhR active substance(s) still remain to be

  7. Laboratory testing of hemolytic properties of materials that come in contact with blood: Comparative application testing method’s two variants according to the standard ASTM F756 in accordance with ISO 10993-4

    Directory of Open Access Journals (Sweden)

    Pavlović Katarina B.

    2010-01-01

    Full Text Available The presence of hemolytic material in contact with blood may produce increased levels of blood cell lysis and increased levels of plasma hemoglobin. This may induce toxic effects or other effects which may stress the kidneys or other organs. In this paper two variants of in vitro method and obtained results’ comparison were presented for testing of hemolytic properties of six raw materials (Polipropylene Moplen EP 540 P, Policarbonate colorless 164 R-112, Policarbonate brown 164 R-51918, Polietylene NG 3026 K, Polietylene NG - Purell GB 7250, Polietylene VG - Hiplex 5502 for medical device manufacturing and one raw material (Polietylen NG granulate used for infusion solutions’s plastic bottles manufacturing. One of method’s variants relies on raw material direct contact with swine blood and the other on extract of the material contact with swine blood. Both method’s variants imply reading of the absorbance of the supernatant after tubes were incubated and centrifuged. According to values obtained and using the standard curve free hemoglobin concentration is determined and based on this percentage hemolysis of raw material. Positive and negative controls were used in both variants where water for injection (WFI was used as positive control in which partial or complete hemolysis of erythrocytes occurs due to osmotic shock and phosphate buffer saline was used as negative control with no hemolytic property. In this paper comparison of results obtained by both method’s variants for testing of seven raw materials was presented, while these conclusions can not be used neither for all materials, nor for all applications without preliminary testing using both variants and then choosing more sensitive and more reliable one. It was shown and stated in the paper as well that incubation time being 3, 15 or 24 h, had no impact on the variant’s with direct contact sensitivity. This comparative approach was used for drawing conclusions in terms of

  8. Acrylate Systemic Contact Dermatitis.

    Science.gov (United States)

    Sauder, Maxwell B; Pratt, Melanie D

    2015-01-01

    Acrylates, the 2012 American Contact Dermatitis Society allergen of the year, are found in a range of products including the absorbent materials within feminine hygiene pads. When fully polymerized, acrylates are nonimmunogenic; however, if not completely cured, the monomers can be potent allergens.A 28-year-old woman is presented, who had her teeth varnished with Isodan (Septodont, Saint-Maur-des-Fossés, France) containing HEMA (2-hydroxyethyl methacrylate) with no initial reaction. Approximately 1 month later, the patient developed a genital dermatitis secondary to her feminine hygiene pads. The initial reaction resolved, but 5 months later, the patient developed a systemic contact dermatitis after receiving a second varnishing.The patient was dramatically patch test positive to many acrylates. This case demonstrates a reaction to likely unpolymerized acrylates within a feminine hygiene pad, as well as broad cross-reactivity or cosensitivity to acrylates, and possibly a systemic contact dermatitis with systemic re-exposure to unpolymerized acrylates.

  9. Prioritized Contact Transport Stream

    Science.gov (United States)

    Hunt, Walter Lee, Jr. (Inventor)

    2015-01-01

    A detection process, contact recognition process, classification process, and identification process are applied to raw sensor data to produce an identified contact record set containing one or more identified contact records. A prioritization process is applied to the identified contact record set to assign a contact priority to each contact record in the identified contact record set. Data are removed from the contact records in the identified contact record set based on the contact priorities assigned to those contact records. A first contact stream is produced from the resulting contact records. The first contact stream is streamed in a contact transport stream. The contact transport stream may include and stream additional contact streams. The contact transport stream may be varied dynamically over time based on parameters such as available bandwidth, contact priority, presence/absence of contacts, system state, and configuration parameters.

  10. Enzyme with rhamnogalacturonase activity.

    NARCIS (Netherlands)

    Kofod, L.V.; Andersen, L.N.; Dalboge, H.; Kauppinen, M.S.; Christgau, S.; Heldt-Hansen, H.P.; Christophersen, C.; Nielsen, P.M.; Voragen, A.G.J.; Schols, H.A.

    1998-01-01

    An enzyme exhibiting rhamnogalacturonase activity, capable of cleaving a rhamnogalacturonan backbone in such a manner that galacturonic acids are left as the non-reducing ends, and which exhibits activity on hairy regions from a soy bean material and/or on saponified hairy regions from a sugar beet

  11. Cellulolytic enzyme compositions and uses thereof

    Energy Technology Data Exchange (ETDEWEB)

    Iyer, Prashant; Gaspar, Armindo Ribiero; Croonenberghs, James; Binder, Thomas P.

    2017-07-25

    The present invention relates enzyme composition comprising a cellulolytic preparation and an acetylxylan esterase (AXE); and the used of cellulolytic enzyme compositions for hydrolyzing acetylated cellulosic material. Finally the invention also relates to processes of producing fermentation products from acetylated cellulosic materials using a cellulolytic enzyme composition of the invention.

  12. Pulsed Current Static Electrical Contact Experiment

    National Research Council Canada - National Science Library

    Jones, Harry N; Neri, Jesse M; Boyer, Craig N; Cooper, Khershed P; Meger, Robert A

    2006-01-01

    .... The voltage developed across the interface is directly related to the contact temperature and pressure, the number of a-spots, the thermophysical and mechanical properties of the contacting materials...

  13. Non-contact ultrasound techniques

    International Nuclear Information System (INIS)

    Khazali Mohd Zin

    2001-01-01

    Non-contact ultrasound plays significant role in material characterisation and inspection. Unlike conventional ultrasonic techniques, non-contact ultrasonic is mostly applicable to areas where the former has its weaknesses and limitations. It is interesting to note that the non-contact ultrasonic technique has an important significant application in industry. The technique is signified by the fact that the object to be inspected is further away from the ultrasonic source, no couplant is needed and inconsistent pressure between the transducer and the specimen can be eliminated. The paper discusses some of the non-contact ultrasound technique and its applications. (Author)

  14. Process for preparing multilayer enzyme coating on a fiber

    Science.gov (United States)

    Kim, Jungbae [Richland, WA; Kwak, Ja Hun [Richland, WA; Grate, Jay W [West Richland, WA

    2009-11-03

    A process for preparing high stability, high activity biocatalytic materials is disclosed and processes for using the same. The process involves coating of a material or fiber with enzymes and enzyme aggregate providing a material or fiber with high biocatalytic activity and stability useful in heterogeneous environments. In one illustrative approach, enzyme "seeds" are covalently attached to polymer nanofibers followed by treatment with a reagent that crosslinks additional enzyme molecules to the seed enzymes forming enzyme aggregates thereby improving biocatalytic activity due to increased enzyme loading and enzyme stability. This approach creates a useful new biocatalytic immobilized enzyme system with potential applications in bioconversion, bioremediation, biosensors, and biofuel cells.

  15. Phthalates in soft PVC products used in food production equipment and in other food contact materials on the Danish and the Nordic Market 2013-2014

    DEFF Research Database (Denmark)

    Petersen, Jens Højslev; Jensen, Lisbeth Krüger

    2016-01-01

    they were well-known endocrine disruptors. Results of the Danish Food Authorities control in 2008 and 2009 showed 23 % non-compliant samples. Critical FCMs turned out to be those made from plasticised PVC and sold as suitable for contact with fatty foodstuffs. Targeted follow up control campaigns were...

  16. Thermal contact conductance

    CERN Document Server

    Madhusudana, Chakravarti V

    2013-01-01

    The work covers both theoretical and practical aspects of thermal contact conductance. The theoretical discussion focuses on heat transfer through spots, joints, and surfaces, as well as the role of interstitial materials (both planned and inadvertent). The practical discussion includes formulae and data that can be used in designing heat-transfer equipment for a variety of joints, including special geometries and configurations. All of the material has been updated to reflect the latest advances in the field.

  17. [Potentialization of antibiotics by lytic enzymes].

    Science.gov (United States)

    Brisou, J; Babin, P; Babin, R

    1975-01-01

    Few lytic enzymes, specially papaine and lysozyme, acting on the membrane and cell wall structures facilitate effects of bacitracine, streptomycine and other antibiotics. Streptomycino resistant strains became sensibles to this antibiotic after contact with papaine and lysozyme. The results of tests in physiological suspensions concern only the lytic activity of enzymes. The results on nutrient medium concern together lytic, and antibiotic activities.

  18. LaNi0.6Co0 4O3-δ dip-coated on Fe-Cr mesh as a composite cathode contact material on intermediate solid oxide fuel cells

    Science.gov (United States)

    Morán-Ruiz, Aroa; Vidal, Karmele; Larrañaga, Aitor; Laguna-Bercero, Miguel Angel; Porras-Vázquez, Jose Manuel; Slater, Peter Raymond; Arriortua, María Isabel

    2014-12-01

    The feasibility of using Crofer22APU mesh dip coated with LaNi0.6Co0.4O3-δ (LNC) ceramic paste as a uniform contact layer on a Crofer22APU channeled interconnect was studied. The control of LNC dip coating thickness on Fe-Cr mesh was carried out by rheological measurements of the suspension. SEM cross-section of formed composite contact material showed good adherence between ceramic and metallic components. The measured area specific resistance (ASR) value at 800 °C was 0.46 ± 0.01 mΩ cm2, indicating low contact resistance itself. The long term stability of metallic/ceramic composite was also studied. The contact resistance, when composite contact material was adhered to channeled Crofer22APU interconnect, was 5.40 ± 0.01 mΩ cm2, which is a suitable value for the performance of IT-SOFC stack. The stability of the system after treating at 800 °C for 1000 h was characterized using X-ray Micro-Diffraction (XRMD), Scanning Electron Microscope equipped with an Energy Dispersive X-ray analyzer (SEM-EDX) and X-ray Photoelectron Spectroscopy (XPS) techniques. The oxidation rate of the alloy and Fe3O4 phase formation were enhanced on the channels of the interconnect. Thus, the formation of CrO3 (g) and CrO2(OH)2 (g) species was accelerated on the composite surface under the channel. Through XRMD and XPS analysis the coexistence of two perovskite phases (initial LNC and Cr-perovskite) was observed.

  19. Contact Lens Care

    Science.gov (United States)

    ... Consumers Consumer Information by Audience For Women Contact Lens Care Share Tweet Linkedin Pin it More sharing ... www.fda.gov/medwatch Learn More about Contact Lens Care Other Tips on Contact Lenses Decorative Contact ...

  20. Enzyme stabilization for pesticide degradation

    Energy Technology Data Exchange (ETDEWEB)

    Rivers, D.B.; Frazer, F.R. III; Mason, D.W.; Tice, T.R.

    1988-01-01

    Enzymes offer inherent advantages and limitations as active components of formulations used to decontaminate soil and equipment contaminated with toxic materials such as pesticides. Because of the catalytic nature of enzymes, each molecule of enzyme has the potential to destroy countless molecules of a contaminating toxic compound. This degradation takes place under mild environmental conditions of pH, temperature, pressure, and solvent. The basic limitation of enzymes is their degree of stability during storage and application conditions. Stabilizing methods such as the use of additives, covalent crosslinking, covalent attachment, gel entrapment, and microencapsulation have been directed developing an enzyme preparation that is stable under extremes of pH, temperature, and exposure to organic solvents. Initial studies were conducted using the model enzymes subtilisin and horseradish peroxidase.

  1. Materialism.

    Science.gov (United States)

    Melnyk, Andrew

    2012-05-01

    Materialism is nearly universally assumed by cognitive scientists. Intuitively, materialism says that a person's mental states are nothing over and above his or her material states, while dualism denies this. Philosophers have introduced concepts (e.g., realization and supervenience) to assist in formulating the theses of materialism and dualism with more precision, and distinguished among importantly different versions of each view (e.g., eliminative materialism, substance dualism, and emergentism). They have also clarified the logic of arguments that use empirical findings to support materialism. Finally, they have devised various objections to materialism, objections that therefore serve also as arguments for dualism. These objections typically center around two features of mental states that materialism has had trouble in accommodating. The first feature is intentionality, the property of representing, or being about, objects, properties, and states of affairs external to the mental states. The second feature is phenomenal consciousness, the property possessed by many mental states of there being something it is like for the subject of the mental state to be in that mental state. WIREs Cogn Sci 2012, 3:281-292. doi: 10.1002/wcs.1174 For further resources related to this article, please visit the WIREs website. Copyright © 2012 John Wiley & Sons, Ltd.

  2. PROCESS FOR DUST-FREE ENZYME MANUFACTURE

    NARCIS (Netherlands)

    Andela, C.; Feijen, Jan; Dillissen, Marc

    1994-01-01

    New enzyme granules are provided with improved properties. The granules are based on core particles having a good pore size and pore size distribution to allow an enzyme solution to enter into the particle. Accordingly, the core material comprises the enzyme in liquid form, thus eliminating the

  3. Contacting gases and liquids

    International Nuclear Information System (INIS)

    Robinson, L.F.; Cahalan, M.J.

    1980-01-01

    A process is described for contacting substantially immiscible phases to transfer material from one phase to another, which comprises passing the phases through a contactor, while causing portions of at least one phase to be repeatedly passed through at least one other phase. One phase in the contactor is gaseous, and another liquid. A further phase can be liquid or solid The process may be used for extracting impurities from china clay, or extracting uranium values from ore with oxygen gas acting to oxidise the uranium. (author)

  4. Contact ionization ion source

    International Nuclear Information System (INIS)

    Hashmi, N.; Van Der Houven Van Oordt, A.J.

    1975-01-01

    An ion source in which an apertured or foraminous electrode having a multiplicity of openings is spaced from one or more active surfaces of an ionisation electrode, the active surfaces comprising a material capable of ionising by contact ionization a substance to be ionized supplied during operation to the active surface or surfaces comprises means for producing during operation a magnetic field which enables a stable plasma to be formed in the space between the active surface or surfaces and the apertured electrode, the field strength of the magnetic field being preferably in the range between 2 and 8 kilogauss. (U.S.)

  5. Collection and identification of human remains volatiles by non-contact, dynamic airflow sampling and SPME-GC/MS using various sorbent materials.

    Science.gov (United States)

    DeGreeff, Lauryn E; Furton, Kenneth G

    2011-09-01

    Human remains detection canines are used in locating deceased humans in diverse scenarios and environments based on odor produced during the decay process of the human body. It has been established that human remains detection canines are capable of locating human remains specifically, as opposed to living humans or animal remains, thus suggesting a difference in odor between the different sources. This work explores the collection and determination of such odors using a dynamic headspace concentration device. The airflow rate and three sorbent materials-Dukal cotton gauze, Johnson & Johnson cotton-blend gauze, and polyester material-used for odor collection were evaluated using standard compounds. It was determined that higher airflow rates and openly woven material, e.g., Dukal cotton gauze, yielded significantly less total volatile compounds due to compound breakthrough through the sorbent material. Collection from polymer- and cellulose-based materials demonstrated that the molecular backbone of the material is a factor in compound collection as well. Volatiles, including cyclic and straight-chain hydrocarbons, organic acids, sulfides, aldehydes, ketones, and alcohols, were collected from a population of 27 deceased bodies from two collection locations. The common compounds between the subjects were compared and the odor profiles were determined. These odor profiles were compared with those of animal remains and living human subjects collected in the same manner. Principal component analysis showed that the odor profiles of the three sample types were distinct.

  6. Applicability of contact angle techniques used in the analysis of contact lenses, part 1: comparative methodologies.

    Science.gov (United States)

    Campbell, Darren; Carnell, Sarah Maria; Eden, Russell John

    2013-05-01

    Contact angle, as a representative measure of surface wettability, is often employed to interpret contact lens surface properties. The literature is often contradictory and can lead to confusion. This literature review is part of a series regarding the analysis of hydrogel contact lenses using contact angle techniques. Here we present an overview of contact angle terminology, methodology, and analysis. Having discussed this background material, subsequent parts of the series will discuss the analysis of contact lens contact angles and evaluate differences in published laboratory results. The concepts of contact angle, wettability and wetting are presented as an introduction. Contact angle hysteresis is outlined and highlights the advantages in using dynamic analytical techniques over static methods. The surface free energy of a material illustrates how contact angle analysis is capable of providing supplementary surface characterization. Although single values are able to distinguish individual material differences, surface free energy and dynamic methods provide an improved understanding of material behavior. The frequently used sessile drop, captive bubble, and Wilhelmy plate techniques are discussed. Their use as both dynamic and static methods, along with the advantages and disadvantages of each technique, is explained. No single contact angle technique fully characterizes the wettability of a material surface, and the application of complimenting methods allows increased characterization. At present, there is not an ISO standard method designed for soft materials. It is important that each contact angle technique has a standard protocol, as small protocol differences between laboratories often contribute to a variety of published data that are not easily comparable.

  7. Occupational contact urticaria and protein contact dermatitis.

    Science.gov (United States)

    Doutre, Marie-Sylvie

    2005-01-01

    Irritant dermatitis and eczema are the most prevalent occupational skin diseases. Less common are immediate contact reactions such as contact urticaria and protein contact dermatitis. Occupational contact urticaria can be subdivided into two categories, immunological and non immunological. However, some agents can induce these two types of reactions. Contact urticaria to natural rubber latex is particularly frequent among health care personnel, but contact urticaria to a wide variety of other substances occurs in many other occupations. Among those at risk are cooks, bakers, butchers, restaurant personnel, veterinarians, hairdressers, florists, gardeners, and forestry workers. Protein contact dermatitis in some of these occupations is caused principally by proteins of animal or plant origin, especially among individuals with a history of atopic dermatitis. Diagnosis requires careful interrogation, clinical examination and skin tests (open tests and prick tests with immediate lecture) to identify a particular contact allergen.

  8. Effects of junction resistance and counterelectrode material on point-contact tunneling into single- and polycrystalline YBa/sub 2/Cu/sub 3/O/sub 7-y/

    Energy Technology Data Exchange (ETDEWEB)

    Moog, E.R.; Hawley, M.E.; Gray, K.E.; Liu, J.Z.; Hinks, D.G.; Capone, D.W. II; Downey, J.

    1988-06-01

    The effects of junction resistance and counterelectrode material on the results of point-contact tunneling studies into single- and polycrystalline YBa/sub 2/Cu/sub 3/O/sub 7-y/ are illustrated. Although reasonably symmetric I(V) curves predominantly indicate energy gap values /Delta/ /approx/ 20 meV, large asymmetries are often found for high-resistance junctions. Very low-resistance junctions show the expected behavior of pure metallic bridge and indicate /Delta/ /approx/ 25-30 meV.

  9. Occupational protein contact dermatitis.

    Science.gov (United States)

    Barbaud, Annick; Poreaux, Claire; Penven, Emmanuelle; Waton, Julie

    2015-01-01

    Occupational contact dermatitis is generally caused by haptens but can also be induced by proteins causing mainly immunological contact urticaria (ICU); chronic hand eczema in the context of protein contact dermatitis (PCD). In a monocentric retrospective study, from our database, only 31 (0.41%) of patients with contact dermatitis had positive skin tests with proteins: 22 had occupational PCD, 3 had non-occupational PCD, 5 occupational ICU and 1 cook had a neutrophilic fixed food eruption (NFFE) due to fish. From these results and analysis of literature, the characteristics of PCD can be summarized as follows. It is a chronic eczematous dermatitis, possibly exacerbated by work, suggestive if associated with inflammatory perionyxix and immediate erythema with pruritis, to be investigated when the patient resumes work after a period of interruption. Prick tests with the suspected protein-containing material are essential, as patch tests have negative results. In case of multisensitisation revealed by prick tests, it is advisable to analyse IgE against recombinant allergens. A history of atopy, found in 56 to 68% of the patients, has to be checked for. Most of the cases are observed among food-handlers but PCD can also be due to non-edible plants, latex, hydrolysed proteins or animal proteins. Occupational exposure to proteins can thus lead to the development of ICU. Reflecting hypersensitivity to very low concentrations of allergens, investigating ICU therefore requires caution and prick tests should be performed with a diluted form of the causative protein-containing product. Causes are food, especially fruit peel, non-edible plants, cosmetic products, latex, animals.

  10. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... Costume Contact Lenses Can Ruin Vision Eye Makeup Safety In fact, it is illegal to sell colored ...

  11. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... use of colored contact lenses , from the U.S. Food and Drug Administration (FDA). Are the colored lenses ...

  12. Influence of oxygen and long term storage on the profile of volatile compounds released from polymeric multilayer food contact materials sterilized by gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Salafranca, Jesús, E-mail: fjsl@unizar.es [Aragón Institute of Engineering Research (I3A), EINA, Department of Analytical Chemistry, University of Zaragoza, María de Luna 3 (Torres Quevedo Bldg.), 50018 Zaragoza (Spain); Clemente, Isabel, E-mail: isabelclemente1984@gmail.com [Aragón Institute of Engineering Research (I3A), EINA, Department of Analytical Chemistry, University of Zaragoza, María de Luna 3 (Torres Quevedo Bldg.), 50018 Zaragoza (Spain); Isella, Francesca, E-mail: Francesca.Isella@goglio.it [Goglio S.p.A. Packaging Division, Via dell' Industria 7, 21020 Daverio (Italy); Nerín, Cristina, E-mail: cnerin@unizar.es [Aragón Institute of Engineering Research (I3A), EINA, Department of Analytical Chemistry, University of Zaragoza, María de Luna 3 (Torres Quevedo Bldg.), 50018 Zaragoza (Spain); Bosetti, Osvaldo, E-mail: Osvaldo.Bosetti@goglio.it [Goglio S.p.A. Packaging Division, Via dell' Industria 7, 21020 Daverio (Italy)

    2015-06-09

    Highlights: • 13 different food-use multilayers unirradiated and gamma-irradiated were studied. • 60–80 compounds/sample were identified by SPME–GC–MS even after 8-month storage. • Volatile profile of air- and N{sub 2}-filled bags greatly differed after irradiation. • Principal component analysis classified the samples into 4 groups. • Migration from irradiated materials to vapor phase was much lower than EU limits. - Abstract: The profile of volatile compounds released from 13 different multilayer polymeric materials for food use, before and after their exposure to gamma radiation, has been assessed by solid-phase microextraction–gas chromatography–mass spectrometry. Thermosealed bags of different materials were filled with either air or nitrogen to evaluate the oxygen influence. One-third of the samples were analyzed without irradiation, whereas the rest were irradiated at 15 and 25 kGy. Half of the samples were processed just after preparation and the other half was stored for 8 months at room temperature prior to analysis. Very significant differences between unirradiated and irradiated bags were found. About 60–80 compounds were released and identified per sample. A huge peak of 1,3-ditertbutylbenzene was present in most of the irradiated samples. An outstanding reproducibility in all the variables evaluated (chromatograms, oxygen percentage, volume of bags) was noticed. Independently of filling gas, the results of unirradiated materials were almost identical. In contrast, the chromatographic profile and the odor of irradiated bags filled with nitrogen were completely different to those filled with air. Principal component analysis was performed and 86.9% of the accumulated variance was explained with the first two components. The migration of compounds from irradiated materials to the vapor phase was much lower than the limits established in the Commission Regulation (EU) No 10/2011.

  13. Imparting functionality to biocatalysts via embedding enzymes into nanoporous materials by a de novo approach: size-selective sheltering of catalase in metal-organic framework microcrystals.

    Science.gov (United States)

    Shieh, Fa-Kuen; Wang, Shao-Chun; Yen, Chia-I; Wu, Chang-Cheng; Dutta, Saikat; Chou, Lien-Yang; Morabito, Joseph V; Hu, Pan; Hsu, Ming-Hua; Wu, Kevin C-W; Tsung, Chia-Kuang

    2015-04-08

    We develop a new concept to impart new functions to biocatalysts by combining enzymes and metal-organic frameworks (MOFs). The proof-of-concept design is demonstrated by embedding catalase molecules into uniformly sized ZIF-90 crystals via a de novo approach. We have carried out electron microscopy, X-ray diffraction, nitrogen sorption, electrophoresis, thermogravimetric analysis, and confocal microscopy to confirm that the ~10 nm catalase molecules are embedded in 2 μm single-crystalline ZIF-90 crystals with ~5 wt % loading. Because catalase is immobilized and sheltered by the ZIF-90 crystals, the composites show activity in hydrogen peroxide degradation even in the presence of protease proteinase K.

  14. Spatially resolved investigation of systemic and contact pesticides in plant material by desorption electrospray ionization mass spectrometry imaging (DESI-MSI).

    Science.gov (United States)

    Gerbig, Stefanie; Brunn, Hubertus E; Spengler, Bernhard; Schulz, Sabine

    2015-09-01

    Distribution of pesticides both on the surface of leaves and in cross sections of plant stem and leaves was investigated using desorption electrospray ionization mass spectrometry imaging (DESI-MSI) with a spatial resolution of 50-100 μm. Two commercially available insecticide sprays containing different contact pesticides were applied onto leaves of Cotoneaster horizontalis, and the distributions of all active ingredients were directly analyzed. The first spray contained pyrethrins and rapeseed oil, both known as natural insecticides. Each component showed an inhomogeneous spreading throughout the leaf, based on substance polarity and solubility. The second spray contained the synthetic insecticides imidacloprid and methiocarb. Imidacloprid accumulated on the border of the leaf, while methiocarb was distributed more homogenously. In order to investigate the incorporation of a systemically acting pesticide into Kalanchoe blossfeldiana, a commercially available insecticide tablet containing dimethoate was spiked to the soil of the plant. Cross sections of the stem and leaf were obtained 25 and 60 days after application. Dimethoate was mainly detected in the transport system of the plant after 25 days, while it was found to be homogenously distributed in a leaf section after 60 days.

  15. Estimating the Contact Endurance of the AISI 321 Stainless Steel Under Contact Gigacycle Fatigue Tests

    Science.gov (United States)

    Savrai, R. A.; Makarov, A. V.; Osintseva, A. L.; Malygina, I. Yu.

    2018-02-01

    Mechanical testing of the AISI 321 corrosion resistant austenitic steel for contact gigacycle fatigue has been conducted with the application of a new method of contact fatigue testing with ultrasonic frequency of loading according to a pulsing impact "plane-to-plane" contact scheme. It has been found that the contact endurance (the ability to resist the fatigue spalling) of the AISI 321 steel under contact gigacycle fatigue loading is determined by its plasticity margin and the possibility of additional hardening under contact loading. It is demonstrated that the appearance of localized deep and long areas of spalling on a material surface can serve as a qualitative characteristic for the loss of the fatigue strength of the AISI 321 steel under impact contact fatigue loading. The value of surface microhardness measured within contact spots and the maximum depth of contact damages in the peripheral zone of contact spots can serve as quantitative criteria for that purpose.

  16. Materials

    CSIR Research Space (South Africa)

    Van Wyk, Llewellyn V

    2009-02-01

    Full Text Available . It is generally included as part of a structurally insulated panel (SIP) where the foam is sandwiched between external skins of steel, wood or cement. Cement composites Cement bonded composites are an important class of building materials. These products... for their stone buildings, including the Egyptians, Aztecs and Inca’s. As stone is a very dense material it requires intensive heating to become warm. Rocks were generally stacked dry but mud, and later cement, can be used as a mortar to hold the rocks...

  17. Improved single- and multi-contact life-time testing of dental restorative materials using key characteristics of the human masticatory system and a force/position-controlled robotic dental wear simulator.

    Science.gov (United States)

    Raabe, D; Harrison, A; Ireland, A; Alemzadeh, K; Sandy, J; Dogramadzi, S; Melhuish, C; Burgess, S

    2012-03-01

    . Experimental studies of wear using this simulator demonstrate that integrating the biological feature of combined force/position hybrid control in dental material testing improves the linearity and reduces the variability of results. In addition, it has been shown that present biaxially operated dental wear simulators are likely to provide misleading results in comparative in vitro/in vivo one-contact studies due to neglecting the occlusal sliding motion in one plane which could introduce an error of up to 49% since occlusal sliding motion D and volumetric wear loss V(loss) are proportional.

  18. Improved single- and multi-contact life-time testing of dental restorative materials using key characteristics of the human masticatory system and a force/position-controlled robotic dental wear simulator

    International Nuclear Information System (INIS)

    Raabe, D; Dogramadzi, S; Melhuish, C; Harrison, A; Alemzadeh, K; Burgess, S; Ireland, A; Sandy, J

    2012-01-01

    . Experimental studies of wear using this simulator demonstrate that integrating the biological feature of combined force/position hybrid control in dental material testing improves the linearity and reduces the variability of results. In addition, it has been shown that present biaxially operated dental wear simulators are likely to provide misleading results in comparative in vitro/in vivo one-contact studies due to neglecting the occlusal sliding motion in one plane which could introduce an error of up to 49% since occlusal sliding motion D and volumetric wear loss V loss are proportional.

  19. Contact Dermatitis in Pediatrics.

    Science.gov (United States)

    Pelletier, Janice L; Perez, Caroline; Jacob, Sharon E

    2016-08-01

    Contact dermatitis is an umbrella term that describes the skin's reaction to contacted noxious or allergenic substances. The two main categories of contact dermatitis are irritant type and allergic type. This review discusses the signs, symptoms, causes, and complications of contact dermatitis. It addresses the testing, treatment, and prevention of contact dermatitis. Proper management of contact dermatitis includes avoidance measures for susceptible children. Implementation of a nickel directive (regulating the use of nickel in jewelry and other products that come into contact with the skin) could further reduce exposure to the most common allergens in the pediatric population. [Pediatr Ann. 2016;45(8):e287-e292.]. Copyright 2016, SLACK Incorporated.

  20. Enzyme detection by microfluidics

    DEFF Research Database (Denmark)

    2013-01-01

    Microfluidic-implemented methods of detecting an enzyme, in particular a DNA-modifying enzyme, are provided, as well as methods for detecting a cell, or a microorganism expressing said enzyme. The enzyme is detected by providing a nucleic acid substrate, which is specifically targeted...... by that enzyme...

  1. Safety and quality of food contact materials. Part 1: evaluation of analytical strategies to introduce migration testing into good manufacturing practice.

    Science.gov (United States)

    Feigenbaum, A; Scholler, D; Bouquant, J; Brigot, G; Ferrier, D; Franzl, R; Lillemarktt, L; Riquet, A M; Petersen, J H; van Lierop, B; Yagoubi, N

    2002-02-01

    The results of a research project (EU AIR Research Programme CT94-1025) aimed to introduce control of migration into good manufacturing practice and into enforcement work are reported. Representative polymer classes were defined on the basis of chemical structure, technological function, migration behaviour and market share. These classes were characterized by analytical methods. Analytical techniques were investigated for identification of potential migrants. High-temperature gas chromatography was shown to be a powerful method and 1H-magnetic resonance provided a convenient fingerprint of plastic materials. Volatile compounds were characterized by headspace techniques, where it was shown to be essential to differentiate volatile compounds desorbed from those generated during the thermal desorption itself. For metal trace analysis, microwave mineralization followed by atomic absorption was employed. These different techniques were introduced into a systematic testing scheme that is envisaged as being suitable both for industrial control and for enforcement laboratories. Guidelines will be proposed in the second part of this paper.

  2. Apparent Contact Angle and Contact Angle Hysteresis on Liquid Infused Surfaces

    OpenAIRE

    Semprebon, Ciro; McHale, Glen; Kusumaatmaja, Halim

    2016-01-01

    We theoretically investigate the apparent contact angle and contact angle hysteresis of a droplet placed on a liquid infused surface. We show that the apparent contact angle is not uniquely defined by material parameters, but also has a strong dependence on the relative size between the droplet and its surrounding wetting ridge formed by the infusing liquid. We derive a closed form expression for the contact angle in the limit of vanishing wetting ridge, and compute the correction for small b...

  3. Apparent contact angle and contact angle hysteresis on liquid infused surfaces.

    Science.gov (United States)

    Semprebon, Ciro; McHale, Glen; Kusumaatmaja, Halim

    2016-12-21

    We theoretically investigate the apparent contact angle and contact angle hysteresis of a droplet placed on a liquid infused surface. We show that the apparent contact angle is not uniquely defined by material parameters, but also has a dependence on the relative size between the droplet and its surrounding wetting ridge formed by the infusing liquid. We derive a closed form expression for the contact angle in the limit of vanishing wetting ridge, and compute the correction for small but finite ridge, which corresponds to an effective line tension term. We also predict contact angle hysteresis on liquid infused surfaces generated by the pinning of the contact lines by the surface corrugations. Our analytical expressions for both the apparent contact angle and contact angle hysteresis can be interpreted as 'weighted sums' between the contact angles of the infusing liquid relative to the droplet and surrounding gas phases, where the weighting coefficients are given by ratios of the fluid surface tensions.

  4. Cosmetic Contact Allergens

    Directory of Open Access Journals (Sweden)

    An Goossens

    2016-02-01

    Full Text Available This article presents trends in the frequency of cosmetics as causal factors of allergic contact dermatitis during a 26-year period in 14,911 patients patch-tested between 1990 and 2014, and discusses the cosmetic allergens identified during the last six years (2010–2015 in 603 patients out of 3105 tested. The data were retrieved from, and evaluated with, a patient database developed in-house. The results show the increasing importance of cosmetic allergies, up to 25% of the patients tested during the last five-year period. As expected, fragrance materials, preservatives, and hair dyes were the most frequent culprits, but a great variety of other allergenic ingredients were involved as well. This underlines the need of additional and extensive patch testing with the patient’s products used and their ingredients.

  5. Hair dye contact allergy

    DEFF Research Database (Denmark)

    Søsted, Heidi; Rastogi, Suresh Chandra; Andersen, Klaus Ejner

    2004-01-01

    Colouring of hair can cause severe allergic contact dermatitis. The most frequently reported hair dye allergens are p-phenylenediamine (PPD) and toluene-2,5-diamine, which are included in, respectively, the patch test standard series and the hairdressers series. The aim of the present study...... was to identify dye precursors and couplers in hair dyeing products causing clinical hair dye dermatitis and to compare the data with the contents of these compounds in a randomly selected set of similar products. The patient material comprised 9 cases of characteristic clinical allergic hair dye reaction, where...... exposure history and patch testing had identified a specific hair dye product as the cause of the reaction. The 9 products used by the patients were subjected to chemical analysis. 8 hair dye products contained toluene-2,5-diamine (0.18 to 0.98%). PPD (0.27%) was found in 1 product, and m-aminophenol (0...

  6. Elevated Liver Enzymes

    Science.gov (United States)

    Symptoms Elevated liver enzymes By Mayo Clinic Staff Elevated liver enzymes may indicate inflammation or damage to cells in the liver. Inflamed or ... than normal amounts of certain chemicals, including liver enzymes, into the bloodstream, which can result in elevated ...

  7. Fluorinated tin oxide back contact for AZTSSe photovoltaic devices

    Energy Technology Data Exchange (ETDEWEB)

    Gershon, Talia S.; Gunawan, Oki; Haight, Richard A.; Lee, Yun Seog

    2017-03-28

    A photovoltaic device includes a substrate, a back contact comprising a stable low-work function material, a photovoltaic absorber material layer comprising Ag.sub.2ZnSn(S,Se).sub.4 (AZTSSe) on a side of the back contact opposite the substrate, wherein the back contact forms an Ohmic contact with the photovoltaic absorber material layer, a buffer layer or Schottky contact layer on a side of the absorber layer opposite the back contact, and a top electrode on a side of the buffer layer opposite the absorber layer.

  8. Contact mechanics: contact area and interfacial separation from small contact to full contact

    International Nuclear Information System (INIS)

    Yang, C; Persson, B N J

    2008-01-01

    We present a molecular dynamics study of the contact between a rigid solid with a randomly rough surface and an elastic block with a flat surface. The numerical calculations mainly focus on the contact area and the interfacial separation from small contact (low load) to full contact (high load). For a small load the contact area varies linearly with the load and the interfacial separation depends logarithmically on the load. For a high load the contact area approaches the nominal contact area (i.e. complete contact), and the interfacial separation approaches zero. The numerical results have been compared with analytical theory and experimental results. They are in good agreement with each other. The present findings may be very important for soft solids, e.g. rubber, or for very smooth surfaces, where complete contact can be reached at moderately high loads without plastic deformation of the solids

  9. Determination of bisphenol-type endocrine disrupting compounds in food-contact recycled-paper materials by focused ultrasonic solid-liquid extraction and ultra performance liquid chromatography-high resolution mass spectrometry.

    Science.gov (United States)

    Pérez-Palacios, David; Fernández-Recio, Miguel Ángel; Moreta, Cristina; Tena, María Teresa

    2012-09-15

    Focused ultrasonic solid-liquid extraction (FUSLE) and reverse-phase ultra performance liquid chromatography (UPLC) coupled to a quadrupole-time of flight mass spectrometer (Q-TOF-MS) was applied to the determination of bisphenol-type endocrine disrupting compounds (EDCs) in food-contact recycled-paper materials. Recycled paper is a potential source of EDCs. Bisphenol A (BPA), bisphenol F (BPF) and their derivatives bisphenol A diglycidyl ether (BADGE) and bisphenol F diglycidyl ether (BFDGE) are used for the production of epoxy resins employed in the formulation of printing inks. The FUSLE of bisphenol-type EDCs from packaging is reported for the first time. First, different extraction solvents were studied and methanol was selected. Then, the main FUSLE factors affecting the extraction efficiency (solvent volume, extraction time and ultrasonic irradiation power) were studied by means of a central composite design. The FUSLE conditions selected for further experiments were 20 ml of methanol at ultrasonic amplitude of 100% for 5s. Finally, the number of extraction cycles necessary for complete extraction was established in two. The analysis of the FUSLE extracts was carried out by UPLC-Q-TOF-MS with electrospray ionization and the determination of the four analytes took place in only 4 min. The FUSLE and UPLC-ESI-QTOF-MS method was validated and applied to the analysis of different food-contact recycled-paper-based materials and packaging. The proposed method provided recoveries from 72% to 97%, repeatability and intermediate precision under 9% and 14%, respectively, and detection limits of 0.33, 0.16, 0.65 and 0.40 μg/g for BPA, BPF, BADGE and BFDGE, respectively. The analysis of paper and cardboard samples confirmed the presence of EDCs in these packaging. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Dimeric assembly of enterocyte brush border enzymes

    DEFF Research Database (Denmark)

    Danielsen, E M

    1994-01-01

    The noncovalent, dimeric assembly of small intestinal brush border enzymes was studied by sedimentation analysis in density gradients of extracts of pulse-labeled pig jejunal mucosal explants. Like aminopeptidase N (EC 3.4.11.2), sucrase-isomaltase (EC 3.2.1.48-10), aminopeptidase A (EC 3...... appearance of the liposome-reconstituted enzyme [Norén et al. (1986) J. Biol. Chem. 261, 12306-12309], showing only the inner, membrane-anchored domains of the monomers to be in close contact with one another while the outer domains are far apart. In contrast to the other brush border enzymes studied...

  11. Amalgam Contact Hypersensitivity Lesion: An Unusual Presentation ...

    African Journals Online (AJOL)

    Contact allergic reactions due to hypersensitivity to dental materials in professionals and ... Keywords: Amalgam, Amalgam contact hypersensitivity lesion, Lichenoid reaction, Oral mucosa ... was associated with mild burning sensation. The patient did ... OLLD in which oral and/or skin lesions appear in temporal association ...

  12. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Cleveland. "This is far from the truth." Real People, Real Problems with Colored Contact Lenses Julian: Teenager ... about the members of the eye-care team . Consumer warning about the improper use of colored contact ...

  13. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... new application of artificial intelligence shows whether a patient’s eyes point to high blood pressure or risk ...

  14. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Costume Contacts May Contain Chemicals Harmful to Eyes Four Ways Over-the-Counter Costume Contact Lenses Can ... was in severe pain and on medication for four weeks, and couldn't see well enough to ...

  15. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... sell contacts without a prescription are breaking the law, and may be fined $11,000 per violation. " ... wear any kind of contact lens. In Butler's case, the lenses caused an infection and left her ...

  16. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Hazard: The Hidden Dangers of Buying Decorative Contact Lenses Without a Prescription Leer en Español: Peligros asociados ... truth." Real People, Real Problems with Colored Contact Lenses Julian: Teenager Blinded In One Eye By Non- ...

  17. Colored Contact Lens Dangers

    Science.gov (United States)

    ... Hazard: The Hidden Dangers of Buying Decorative Contact Lenses Without a Prescription Leer en Español: Peligros asociados ... truth." Real People, Real Problems with Colored Contact Lenses Julian: Teenager Blinded In One Eye By Non- ...

  18. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Cleveland. "This is far from the truth." Real People, Real Problems with Colored Contact Lenses Julian: Teenager ... the lenses. Never share contact lenses with another person. Get follow up exams with your eye care ...

  19. Contact Angle Goniometer

    Data.gov (United States)

    Federal Laboratory Consortium — Description:The FTA32 goniometer provides video-based contact angle and surface tension measurement. Contact angles are measured by fitting a mathematical expression...

  20. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... like a suction cup." Halloween is a popular time for people to use colored contact lenses to ... wear costume contact lenses for Halloween or any time of year, follow these guidelines: Get an eye ...

  1. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... glow-in-the-dark lizard lenses, costume contacts can certainly add a spooky, eye-popping touch. But ... consideration as a standard contact lens because they can be purchased over-the-counter or on the ...

  2. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... contact lenses , from the U.S. Food and Drug Administration (FDA). Are the colored lenses you are considering ... Follow The Academy Professionals: Education Guidelines News Multimedia Public & Patients: Contact Us About the Academy Jobs at ...

  3. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... not require the same level of care or consideration as a standard contact lens because they can ... sell contacts without a prescription are breaking the law, and may be fined $11,000 per violation. " ...

  4. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... the United States. All contact lenses are medical devices that require a prescription and proper fitting by an eye-care professional. Retailers that sell contacts without a ...

  5. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... prescription. Follow the contact lens care directions for cleaning, disinfecting, and wearing the lenses. Never share contact ... with Industry Medical Disclaimer Privacy Policy Terms of Service For Advertisers For Media Ophthalmology Job Center © American ...

  6. Immobilised enzymes in biorenewable production

    OpenAIRE

    Franssen, M.C.R.; Steunenberg, P.; Scott, E.L.; Zuilhof, H.; Sanders, J.P.M.

    2013-01-01

    Oils, fats, carbohydrates, lignin, and amino acids are all important raw materials for the production of biorenewables. These compounds already play an important role in everyday life in the form of wood, fabrics, starch, paper and rubber. Enzymatic reactions do, in principle, allow the transformation of these raw materials into biorenewables under mild and sustainable conditions. There are a few examples of processes using immobilised enzymes that are already applied on an industrial scale, ...

  7. DNA-Based Enzyme Reactors and Systems

    Directory of Open Access Journals (Sweden)

    Veikko Linko

    2016-07-01

    Full Text Available During recent years, the possibility to create custom biocompatible nanoshapes using DNA as a building material has rapidly emerged. Further, these rationally designed DNA structures could be exploited in positioning pivotal molecules, such as enzymes, with nanometer-level precision. This feature could be used in the fabrication of artificial biochemical machinery that is able to mimic the complex reactions found in living cells. Currently, DNA-enzyme hybrids can be used to control (multi-enzyme cascade reactions and to regulate the enzyme functions and the reaction pathways. Moreover, sophisticated DNA structures can be utilized in encapsulating active enzymes and delivering the molecular cargo into cells. In this review, we focus on the latest enzyme systems based on novel DNA nanostructures: enzyme reactors, regulatory devices and carriers that can find uses in various biotechnological and nanomedical applications.

  8. Contact Lens Risks

    Science.gov (United States)

    ... There is a risk of eye infection from bacteria in swimming pool water, hot tubs, lakes and the ocean Replace your contact lens storage case every 3 months or as directed by your eye care professional. Other Risks of Contact Lenses Other risks of contact lenses include pink eye ( ...

  9. Mixed Lubricated Line Contacts

    NARCIS (Netherlands)

    Faraon, I.C.

    2005-01-01

    The present work deals with friction in mixed lubricated line contacts. Components in systems are becoming smaller and due to, for instance power transmitted, partial contact may occur. In industrial applications, friction between the moving contacting surfaces cannot be avoided, therefore it is

  10. New Cosmetic Contact Allergens

    Directory of Open Access Journals (Sweden)

    An Goossens

    2015-02-01

    Full Text Available Allergic and photo-allergic contact dermatitis, and immunologic contact urticaria are potential immune-mediated adverse effects from cosmetics. Fragrance components and preservatives are certainly the most frequently observed allergens; however, all ingredients must be considered when investigating for contact allergy.

  11. Contact lens surface by electron beam

    International Nuclear Information System (INIS)

    Shin, Jung Hyuck; Lee, Suk Ju; Hwang, Kwang Ha; Jeon Jin

    2011-01-01

    Contact lens materials needs good biocompatibility, high refractive index, high optical transparency, high water content etc. Surface treat method by using plasma and radiation can modify the physical and/or chemical properties of the contact lens surface. Radiation technology such as electron beam irradiation can apply to polymerization reaction and enhance the functionality of the polymer.The purpose of this study is to modify of contact lens surface by using Eb irradiation technology. Electron beam was irradiated to the contact lens surface which was synthesized thermal polymerization method and commercial contact lens to modify physical and chemical properties. Ft-IR, XP, UV-vis spectrophotometer, water content, oxygen trans-metastability were used to characterize the surface state, physicochemical, and optical property of the contact lens treated with Eb. The water content and oxygen transmissibility of the contact lens treated with Eb were increased due to increase in the hydrophilic group such as O-C=O and OH group on the contact lens surface which could be produced by possible reaction between carbon and oxygen during the Eb irradiation. All of the lenses showed the high optical transmittance above 90%. In this case of B/Es, TES, Ti contact lens, the optical transmittance decreased about 5% with increasing Eb dose in the wavelength of UV-B region. The contact lens modified by Eb irradiation could improve the physical properties of the contact lens such as water content and oxygen transmissibility

  12. Deposition of lipid, protein, and secretory phospholipase A2 on hydrophilic contact lenses.

    Science.gov (United States)

    Mochizuki, Hiroshi; Yamada, Masakazu; Hatou, Shin; Kawashima, Motoko; Hata, Seiichiro

    2008-01-01

    Recent studies have shown that low tear phospholipid levels are associated with tear film instability in hydrophilic contact lens wearers. The concentration of secretory phospholipase A2 (sPLA2), the enzyme that hydrolyzes phospholipids, in tears is known to exceed the levels found in serum by four orders of magnitude. This study was performed to determine the levels of sPLA2 from the deposition on two different frequent-replacement contact lens materials. Polymacon and etafilcon A contact lenses worn for 2 weeks by 16 experienced contact lens wearers were used for the analysis. Total lipids were determined by the sulfo-phospho-vanillin reaction. Phospholipids in lipid extracts were estimated by phosphorus determination with ammonium molybdate through enzymatic digestion. Total protein was measured by bicinchoninic acid analysis. Double-antibody sandwich enzyme-linked immunosorbent assay was used to determine sPLA2 concentrations. Total lipid deposition was found to be greater in the polymacon group (66.3+/-16.3 microg/lens) than in the etafilcon A group, although phospholipids were not detected in either group. The etafilcon A group had greater deposition of protein (3.7+/-0.7 mg/lens) than the polymacon group had. The etafilcon A group deposited statistically significantly more group IIa sPLA2 (1.1+/-0.3 microg/lens) than the polymacon group (0.07+/-0.04 microg/lens) did (P<0.001). There was a significant difference in the lipid and protein deposition profiles in the two lenses tested. A significant amount of sPLA2 in the deposition on contact lenses may play a role in tear film instability in hydrophilic contact lens wearers.

  13. EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2014. Scientific Opinion on Flavouring Group Evaluation 82, Revision 1 (FGE.82Rev1): Consideration of Epoxides evaluated by the JECFA (65 th meeting)

    DEFF Research Database (Denmark)

    Beltoft, Vibe Meister; Binderup, Mona-Lise; Frandsen, Henrik Lauritz

    evaluation is necessary, as laid down in Commission Regulation (EC) No 1565/2000. The present consideration concerns a group of five epoxides evaluated by the JECFA at the 65th meeting in 2005. This revision is made due to inclusion of one additional substance, beta-ionone epoxide [FL-no: 07.170], cleared...

  14. CONTACT RESISTANCE MODELING

    Directory of Open Access Journals (Sweden)

    S. V. LOSKUTOV

    2018-05-01

    Full Text Available Purpose. To determine the contribution of the real contact spots distribution in the total conductivity of the conductors contact. Methodology. The electrical contact resistance research was carried out on models. The experimental part of this work was done on paper with a graphite layer with membranes (the first type and conductive liquids with discrete partitions (the second type. Findings. It is shown that the contact electrical resistance is mainly determined by the real area of metal contact. The experimental dependence of the electrical resistance of the second type model on the distance between the electrodes and the potential distribution along the sample surface for the first type model were obtained. The theoretical model based on the principle of electric field superposition was considered. The dependences obtained experimentally and calculated by using the theoretical model are in good agreement. Originality. The regularity of the electrical contact resistance formation on a large number of membranes was researched for the first time. A new model of discrete electrical contact based on the liquid as the conducting environment with nuclear membrane partitions was developed. The conclusions of the additivity of contact and bulk electrical resistance were done. Practical value. Based on these researches, a new experimental method of kinetic macroidentation that as a parameter of the metal surface layer deformation uses the real contact area was developed. This method allows to determine the value of average contact stresses, yield point, change of the stress on the depth of deformation depending on the surface treatment.

  15. Contact planarization of ensemble nanowires

    Science.gov (United States)

    Chia, A. C. E.; LaPierre, R. R.

    2011-06-01

    The viability of four organic polymers (S1808, SC200, SU8 and Cyclotene) as filling materials to achieve planarization of ensemble nanowire arrays is reported. Analysis of the porosity, surface roughness and thermal stability of each filling material was performed. Sonication was used as an effective method to remove the tops of the nanowires (NWs) to achieve complete planarization. Ensemble nanowire devices were fully fabricated and I-V measurements confirmed that Cyclotene effectively planarizes the NWs while still serving the role as an insulating layer between the top and bottom contacts. These processes and analysis can be easily implemented into future characterization and fabrication of ensemble NWs for optoelectronic device applications.

  16. Geopolymer resin materials, geopolymer materials, and materials produced thereby

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Dong-Kyun; Medpelli, Dinesh; Ladd, Danielle; Mesgar, Milad

    2018-01-09

    A product formed from a first material including a geopolymer resin material, a geopolymer material, or a combination thereof by contacting the first material with a fluid and removing at least some of the fluid to yield a product. The first material may be formed by heating and/or aging an initial geopolymer resin material to yield the first material before contacting the first material with the fluid. In some cases, contacting the first material with the fluid breaks up or disintegrates the first material (e.g., in response to contact with the fluid and in the absence of external mechanical stress), thereby forming particles having an external dimension in a range between 1 nm and 2 cm.

  17. Optimizing culture medium for debittering constitutive enzyme ...

    African Journals Online (AJOL)

    STORAGESEVER

    2010-08-02

    Aug 2, 2010 ... enzyme naringinase production by Aspergillus oryzae. JMU316. Dong-xiao .... even though industrial applications of naringinase are becoming more and ... guidance for industry. MATERIALS AND ..... For economic reasons,.

  18. Metal Contacts to Gallium Arsenide.

    Science.gov (United States)

    Ren, Fan

    1991-07-01

    While various high performance devices fabricated from the gallium arsenide (GaAs) and related materials have generated considerable interest, metallization are fundamental components to all semiconductor devices and integrated circuits. The essential roles of metallization systems are providing the desired electrical paths between the active region of the semiconductor and the external circuits through the metal interconnections and contacts. In this work, in-situ clean of native oxide, high temperature n-type, low temperature n-type and low temperature p-type ohmic metal systems have been studied. Argon ion mill was used to remove the native oxide prior to metal deposition. For high temperature process n-type GaAs ohmic contacts, Tungsten (W) and Tungsten Silicide (WSi) were used with an epitaxial grown graded Indium Gallium Arsenide (InGaAs) layer (0.2 eV) on GaAs. In addition, refractory metals, Molybdenum (Mo), was incorporated in the Gold-Germanium (AuGe) based on n-type GaAs ohmic contacts to replace conventional silver as barrier to prevent the reaction between ohmic metal and chlorine based plasma as well as the ohmic metallization intermixing which degrades the device performance. Finally, Indium/Gold-Beryllium (In/Au-Be) alloy has been developed as an ohmic contact for p-type GaAs to reduce the contact resistance. The Fermi-level pinning of GaAs has been dominated by the surface states. The Schottky barrier height of metal contacts are about 0.8 V regardless of the metal systems. By using p-n junction approach, barrier height of pulsed C-doped layers was achieved as high as 1.4 V. Arsenic implantation into GaAs method was also used to enhance the barrier height of 1.6 V.

  19. Contact and symplectic topology

    CERN Document Server

    Colin, Vincent; Stipsicz, András

    2014-01-01

    Symplectic and contact geometry naturally emerged from the mathematical description of classical physics. The discovery of new rigidity phenomena and properties satisfied by these geometric structures launched a new research field worldwide. The intense activity of many European research groups in this field is reflected by the ESF Research Networking Programme "Contact And Symplectic Topology" (CAST). The lectures of the Summer School in Nantes (June 2011) and of the CAST Summer School in Budapest (July 2012) provide a nice panorama of many aspects of the present status of contact and symplectic topology. The notes of the minicourses offer a gentle introduction to topics which have developed in an amazing speed in the recent past. These topics include 3-dimensional and higher dimensional contact topology, Fukaya categories, asymptotically holomorphic methods in contact topology, bordered Floer homology, embedded contact homology, and flexibility results for Stein manifolds.

  20. Relationship between the real contact area and contact force in pre-sliding regime

    International Nuclear Information System (INIS)

    Song Baojiang; Yan Shaoze

    2017-01-01

    The pre-sliding regime is typically neglected in the dynamic modelling of mechanical systems. However, the change in contact state caused by static friction may decrease positional accuracy and control precision. To investigate the relationship between contact status and contact force in pre-sliding friction, an optical experimental method is presented in this paper. With this method, the real contact state at the interface of a transparent material can be observed based on the total reflection principle of light by using an image processing technique. A novel setup, which includes a pair of rectangular trapezoidal blocks, is proposed to solve the challenging issue of accurately applying different tangential and normal forces to the contact interface. The improved Otsu’s method is used for measurement. Through an experimental study performed on polymethyl methacrylate (PMMA), the quantity of contact asperities is proven to be the dominant factor that affects the real contact area. The relationship between the real contact area and the contact force in the pre-sliding regime is studied, and the distribution of static friction at the contact interface is qualitatively discussed. New phenomena in which the real contact area expands along with increasing static friction are identified. The aforementioned relationship is approximately linear at the contact interface under a constant normal pressure, and the distribution of friction stress decreases from the leading edge to the trailing edge. (paper)

  1. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... also available in Spanish . Follow The Academy Professionals: Education Guidelines News Multimedia Public & Patients: Contact Us About the Academy Jobs at the Academy Financial ...

  2. Allergic Contact Dermatitis

    Directory of Open Access Journals (Sweden)

    Meltem Önder

    2009-03-01

    Full Text Available Allergic contact dermatitis is the delayed type hypersensitivity reaction to exogenous agents. Allergic contact dermatitis may clinically present acutely after allergen exposure and initial sensitization in a previously sensitized individual. Acute phase is characterized by erythematous, scaly plaques. In severe cases vesiculation and bullae in exposed areas are very characteristic. Repeated or continuous exposure of sensitized individual with allergen result in chronic dermatitis. Lichenification, erythematous plaques, hyperkeratosis and fissuring may develop in chronic patients. Allergic contact dermatitis is very common dermatologic problem in dermatology daily practice. A diagnosis of contact dermatitis requires the careful consideration of patient history, physical examination and patch testing. The knowledge of the clinical features of the skin reactions to various contactans is important to make a correct diagnosis of contact dermatitis. It can be seen in every age, in children textile product, accessories and touch products are common allergens, while in adults allergic contact dermatitis may be related with topical medicaments. The contact pattern of contact dermatitis depends on fashion and local traditions as well. The localization of allergic reaction should be evaluated and patients’ occupation and hobbies should be asked. The purpose of this review is to introduce to our collaques up dated allergic contact dermatitis literatures both in Turkey and in the World.

  3. Colors and contact dermatitis.

    Science.gov (United States)

    Bonamonte, Domenico; Foti, Caterina; Romita, Paolo; Vestita, Michelangelo; Angelini, Gianni

    2014-01-01

    The diagnosis of skin diseases relies on several clinical signs, among which color is of paramount importance. In this review, we consider certain clinical presentations of both eczematous and noneczematous contact dermatitis in which color plays a peculiar role orientating toward the right diagnosis. The conditions that will be discussed include specific clinical-morphologic subtypes of eczematous contact dermatitis, primary melanocytic, and nonmelanocytic contact hyperchromia, black dermographism, contact chemical leukoderma, and others. Based on the physical, chemical, and biologic factors underlying a healthy skin color, the various skin shades drawing a disease picture are thoroughly debated, stressing their etiopathogenic origins and histopathologic aspects.

  4. How Do Enzymes 'Meet' Nanoparticles and Nanomaterials?

    Science.gov (United States)

    Chen, Ming; Zeng, Guangming; Xu, Piao; Lai, Cui; Tang, Lin

    2017-11-01

    Enzymes are fundamental biological catalysts responsible for biological regulation and metabolism. The opportunity for enzymes to 'meet' nanoparticles and nanomaterials is rapidly increasing due to growing demands for applications in nanomaterial design, environmental monitoring, biochemical engineering, and biomedicine. Therefore, understanding the nature of nanomaterial-enzyme interactions is becoming important. Since 2014, enzymes have been used to modify, degrade, or make nanoparticles/nanomaterials, while numerous nanoparticles/nanomaterials have been used as materials for enzymatic immobilization and biosensors and as enzyme mimicry. Among the various nanoparticles and nanomaterials, metal nanoparticles and carbon nanomaterials have received extensive attention due to their fascinating properties. This review provides an overview about how enzymes meet nanoparticles and nanomaterials. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Geopolymer resin materials, geopolymer materials, and materials produced thereby

    Science.gov (United States)

    Seo, Dong-Kyun; Medpelli, Dinesh; Ladd, Danielle; Mesgar, Milad

    2016-03-29

    A product formed from a first material including a geopolymer resin material, a geopolymer resin, or a combination thereof by contacting the first material with a fluid and removing at least some of the fluid to yield a product. The first material may be formed by heating and/or aging an initial geopolymer resin material to yield the first material before contacting the first material with the fluid. In some cases, contacting the first material with the fluid breaks up or disintegrates the first material (e.g., in response to contact with the fluid and in the absence of external mechanical stress), thereby forming particles having an external dimension in a range between 1 nm and 2 cm.

  6. Enzyme inhibition by iminosugars

    DEFF Research Database (Denmark)

    López, Óscar; Qing, Feng-Ling; Pedersen, Christian Marcus

    2013-01-01

    Imino- and azasugar glycosidase inhibitors display pH dependant inhibition reflecting that both the inhibitor and the enzyme active site have groups that change protonation state with pH. With the enzyme having two acidic groups and the inhibitor one basic group, enzyme-inhibitor complexes...

  7. Electrodeposition of enzymes-integrated mesoporous composite films by interfacial templating: A paradigm for electrochemical biosensors

    International Nuclear Information System (INIS)

    Wang, Dongming; Tan, Yiwei

    2014-01-01

    The development of nanostructured electrodes for electrochemical biosensors is of significant interest for modern detection, portable devices, and enhanced performance. However, development of such sensors still remains challenging due to the time-consuming, detriment-to-nature, and costly modifications of both electrodes and enzymes. In this work, we report a simple one-step approach to fabricating high-performance, direct electron transfer (DET) based nanoporous enzyme-embedded electrodes by electrodeposition coupled with recent progress in potential-controlled interfacial surfactant assemblies. In contrast to those previously electrodeposited mesoporous materials that are not bioactive, we imparted the biofunctionality to electrodeposited mesoporous thin films by means of the amphiphilic phospholipid templates strongly interacting with enzymes. Thus, phospholipid-templated mesoporous ZnO films covalently inlaid with the pristine enzymes were prepared by simple one-step electrodeposition. We further demonstrate two examples of such hybrid film electrodes embedded with alcohol dehydrogenase (ADH) and glucose oxidase (GOx), which are effectively employed as electrochemical biosensors for amperometric sensing of ethanol and glucose without using any electron relays. The favorable mass transport and large contact surface area provided by nanopores play an important role in improving the performance of these two biosensors, such as excellent sensitivities, low detection limits, and fast response. The matrix mesoporous films acting as effective electronic bridges are responsible for DET between enzyme molecules and metal electrode

  8. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... eye-care professional. Retailers that sell contacts without a prescription are breaking the law, and may be fined $11,000 per violation. "Many of the lenses found online or in beauty salons, novelty shops or in pop-up ... contact lenses from a retailer that does not ask for a prescription. ...

  9. Electric contact arcing

    International Nuclear Information System (INIS)

    Cuthrell, R.E.

    1976-01-01

    Electrical contacts must function properly in many types of components used in nuclear weapon systems. Design, application, and testing of these components require detailed knowledge of chemical and physical phenomena associated with stockpile storage, stockpile testing, and operation. In the past, investigation of these phenomena has led to significant discoveries on the effects of surface contaminants, friction and wear, and the mechanics of closure on contact performance. A recent investigation of contact arcing phenomena which revealed that, preceding contact closure, arcs may occur at voltages lower than had been previously known is described. This discovery is important, since arcing may damage contacts, and repetitive testing of contacts performed as part of a quality assurance program might produce cumulative damage that would yield misleading life-test data and could prevent proper operation of the contacts at some time in the future. This damage can be avoided by determining the conditions under which arcing occurs, and ensuring that these conditions are avoided in contact testing

  10. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Get follow up exams with your eye care provider. If you notice redness, swelling, excessive discharge, pain or discomfort from wearing contact lenses, remove the lenses and seek immediate medical attention from an ophthalmologist. Related resources: Learn how to properly care for contact lenses . ...

  11. Sciences & Nature: Contact

    African Journals Online (AJOL)

    Principal Contact. Ehouan Etienne Ehile Professor University of Abobo-Adjamé 02 BP 801 Abidjan 02. Phone: (+225) 2030 4201. Fax: (+225) 2030 4203. Email: eh_ehile@yahoo.fr. Support Contact. Irie Zoro Bi Email: banhiakalou@yahoo.fr. ISSN: 1812-0741. AJOL African Journals Online. HOW TO USE AJOL.

  12. Contact Us | DOepatents

    Science.gov (United States)

    advance. Your help is appreciated. Contact us by email Email doepatentscomments@osti.gov NOTE: Email us by phone Phone Phone (865) 241-5275 Contact us in writing Mail U.S. Department of Energy Office of non-federal websites. Their policies may differ from this site. Javascript Not Enabled Email Link

  13. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... eye-care team . Consumer warning about the improper use of colored contact lenses , from the U.S. Food and Drug Administration (FDA). Are the colored lenses you are considering buying approved by the FDA? Check the FDA's database of approved contact lenses . Related Stories Prevent Infection ...

  14. Contact dermatitis. A review

    DEFF Research Database (Denmark)

    Andersen, Klaus Ejner; Benezra, C; Burrows, D

    1987-01-01

    In recent years, there has been a dramatic rise in our understanding of contact dermatitis. This paper is a review of our knowledge of the mechanisms involved in contact dermatitis and related phenomena, the investigation of these events and the emergence of significant new allergens during...

  15. Contact Hamiltonian mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Bravetti, Alessandro, E-mail: alessandro.bravetti@iimas.unam.mx [Instituto de Investigaciones en Matemáticas Aplicadas y en Sistemas, Universidad Nacional Autónoma de México, A. P. 70543, México, DF 04510 (Mexico); Cruz, Hans, E-mail: hans@ciencias.unam.mx [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, A. P. 70543, México, DF 04510 (Mexico); Tapias, Diego, E-mail: diego.tapias@nucleares.unam.mx [Facultad de Ciencias, Universidad Nacional Autónoma de México, A.P. 70543, México, DF 04510 (Mexico)

    2017-01-15

    In this work we introduce contact Hamiltonian mechanics, an extension of symplectic Hamiltonian mechanics, and show that it is a natural candidate for a geometric description of non-dissipative and dissipative systems. For this purpose we review in detail the major features of standard symplectic Hamiltonian dynamics and show that all of them can be generalized to the contact case.

  16. Contact Quality in Participation

    DEFF Research Database (Denmark)

    Simonsen, Jesper; Jensen, Olav Storm

    2016-01-01

    We investigate the concept of participation from the perspective of quality of the contact in the communicative interactions between participants. We argue for the need for an academic-personal competence that qualifies the human contact central in all Participatory Design (PD) activities as a way...

  17. Nigerian Food Journal: Contact

    African Journals Online (AJOL)

    Nigerian Food Journal. ... Nigerian Food Journal: Contact. Journal Home > About the Journal > Nigerian Food Journal: Contact. Log in or Register to get access to full text downloads. ... Mailing Address. Department of Food Science and Technology University of Agriculture, Makurdi, Nigeria ...

  18. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... like a suction cup." Halloween is a popular time for people to use colored contact lenses to enhance their costumes. From ... MD, professor of ophthalmology at Case Western Reserve University in Cleveland. "This is far ... Use Facts About Colored Contacts and Halloween Safety Colored ...

  19. Engineering Cellulase Enzymes for Bioenergy

    Science.gov (United States)

    Atreya, Meera Elizabeth

    Sustainable energy sources, such as biofuels, offer increasingly important alternatives to fossil fuels that contribute less to global climate change. The energy contained within cellulosic biofuels derives from sunlight energy stored in the form of carbon-carbon bonds comprising sugars such as glucose. Second-generation biofuels are produced from lignocellulosic biomass feedstocks, including agricultural waste products and non-food crops like Miscanthus, that contain lignin and the polysaccharides hemicellulose and cellulose. Cellulose is the most abundant biological material on Earth; it is a polymer of glucose and a structural component of plant cell walls. Accessing the sugar is challenging, as the crystalline structure of cellulose resists degradation; biochemical and thermochemical means can be used to depolymerize cellulose. Cellulase enzymes catalyze the biochemical depolymerization of cellulose into glucose. Glucose can be used as a carbon source for growth of a biofuel-producing microorganism. When it converts glucose to a hydrocarbon fuel, this microbe completes the biofuels process of transforming sunlight energy into accessible, chemical energy capable of replacing non-renewable transportation fuels. Due to strong intermolecular interactions between polymer chains, cellulose is significantly more challenging to depolymerize than starch, a more accessible polymer of glucose utilized in first-generation biofuels processes (often derived from corn). While most mammals cannot digest cellulose (dietary fiber), certain fungi and bacteria produce cellulase enzymes capable of hydrolyzing it. These organisms secrete a wide variety of glycoside hydrolase and other classes of enzymes that work in concert. Because cellulase enzymes are slow-acting and expensive to produce, my aim has been to improve the properties of these enzymes as a means to make a cellulosic biofuels process possible that is more efficient and, consequently, more economical than current

  20. Noneczematous Contact Dermatitis

    Science.gov (United States)

    Foti, Caterina; Vestita, Michelangelo; Angelini, Gianni

    2013-01-01

    Irritant or allergic contact dermatitis usually presents as an eczematous process, clinically characterized by erythematoedematovesicous lesions with intense itching in the acute phase. Such manifestations become erythematous-scaly as the condition progresses to the subacute phase and papular-hyperkeratotic in the chronic phase. Not infrequently, however, contact dermatitis presents with noneczematous features. The reasons underlying this clinical polymorphism lie in the different noxae and contact modalities, as well as in the individual susceptibility and the various targeted cutaneous structures. The most represented forms of non-eczematous contact dermatitis include the erythema multiforme-like, the purpuric, the lichenoid, and the pigmented kinds. These clinical entities must obviously be discerned from the corresponding “pure” dermatitis, which are not associated with contact with exogenous agents. PMID:24109520

  1. Instrument for measuring metal-thermoelectric semiconductor contact resistence

    International Nuclear Information System (INIS)

    Lanxner, M.; Nechmadi, M.; Meiri, B.; Schildkraut, I.

    1979-02-01

    An instrument for measuring electrical, metal-thermoelectric semiconductor contact resistance is described. The expected errors of measurement are indicated. The operation of the instrument which is based on potential traversing perpendicularly to the contact plane is illustrated for the case of contacts of palladium and bismuth telluride-based thermoelectric material

  2. Screening genus Penicillium for producers of cellulolytic and xylanolytic enzymes

    DEFF Research Database (Denmark)

    Krogh, Kristian Bertel Rømer; Mørkeberg, Astrid; Frisvad, Jens Christian

    2004-01-01

    For enzymatic hydrolysis of lignocellulosic material, cellulolytic enzymes from Trichoderma reesei are most commenly used, but, there is a need for more efficient enzyme cocktails. In this study, the production of cellulolytic and xylanolytic enzymes was investigated in 12 filamentous fungi from ...

  3. Towards a generic procedure for the detection of relevant contaminants from waste electric and electronic equipment (WEEE) in plastic food-contact materials: a review and selection of key parameters.

    Science.gov (United States)

    Puype, Franky; Samsonek, Jiří; Vilímková, Věra; Kopečková, Šárka; Ratiborská, Andrea; Knoop, Jan; Egelkraut-Holtus, Marion; Ortlieb, Markus; Oppermann, Uwe

    2017-10-01

    Recently, traces of brominated flame retardants (BFRs) have been detected in black plastic food-contact materials (FCMs), indicating the presence of recycled plastics, mainly coming from waste electric and electronic equipment (WEEE) as BFRs are one of the main additives in electric applications. In order to evaluate efficiently and preliminary in situ the presence of WEEE in plastic FCMs, a generic procedure for the evaluation of WEEE presence in plastic FCMs by using defined parameters having each an associated importance level has been proposed. This can be achieved by combining parameters like overall bromine (Br) and antimony (Sb) content; additive and reactive BFR, rare earth element (REE) and WEEE-relevant elemental content and additionally polymer purity. In most of the cases, the WEEE contamination could be confirmed by combining X-ray fluorescence (XRF) spectrometry and thermal desorption/pyrolysis gas chromatography-mass spectrometry (GC-MS) at first. The Sb and REE content did not give a full confirmation as to the source of contamination, however for Sb the opposite counts: Sb was joined with elevated Br signals. Therefore, Br at first followed by Sb were used as WEEE precursors as both elements are used as synergetic flame-retardant systems. WEEE-specific REEs could be used for small WEEE (sWEEE) confirmation; however, this parameter should be interpreted with care. The polymer purity by Fourier-transform infrared spectrometer (FTIR) and pyrolysis GC-MS in many cases could not confirm WEEE-specific contamination; however, it can be used for purity measurements and for the suspicion of the usage of recycled fractions (WEEE and non-WEEE) as a third-line confirmation. To the best of our knowledge, the addition of WEEE waste to plastic FCMs is illegal; however, due to lack on screening mechanisms, there is still the breakthrough of such articles onto the market, and, therefore, our generic procedure enables the quick and effective screening of suspicious

  4. Characterization of estrogen and androgen activity of food contact materials by different in vitro bioassays (YES, YAS, ERα and AR CALUX and chromatographic analysis (GC-MS, HPLC-MS.

    Directory of Open Access Journals (Sweden)

    Johannes Mertl

    Full Text Available Endocrine active substances (EAS show structural similarities to natural hormones and are suspected to affect the human endocrine system by inducing hormone dependent effects. Recent studies with in vitro tests suggest that EAS can leach from packaging into food and may therefore pose a risk to human health. Sample migrates from food contact materials were tested for estrogen and androgen agonists and antagonists with different commonly used in vitro tests. Additionally, chemical trace analysis by GC-MS and HPLC-MS was used to identify potential hormone active substances in sample migrates. A GC-MS method to screen migrates for 29 known or potential endocrine active substances was established and validated. Samples were migrated according to EC 10/2011, concentrated by solid phase extraction and tested with estrogen and androgen responsive reporter gene assays based on yeast cells (YES and YAS or human osteoblast cells (ERα and AR CALUX. A high level of agreement between the different bioassays could be observed by screening for estrogen agonists. Four out of 18 samples tested showed an estrogen activity in a similar range in both, YES and ERα CALUX. Two more samples tested positive in ERα CALUX due to the lower limits of detection in this assay. Androgen agonists could not be detected in any of the tested samples, neither with YAS nor with AR CALUX. When testing for antagonists, significant differences between yeast and human cell-based bioassays were noticed. Using YES and YAS many samples showed a strong antagonistic activity which was not observed using human cell-based CALUX assays. By GC-MS, some known or supposed EAS were identified in sample migrates that showed a biological activity in the in vitro tests. However, no firm conclusions about the sources of the observed hormone activity could be obtained from the chemical results.

  5. Development of enzymes and enzyme systems by genetic engineering to convert biomass to sugars

    Science.gov (United States)

    TITLE Development of Enzymes and Enzyme Systems by Genetic Engineering to Convert Biomass to Sugars ABSTRACT Plant cellulosic material is one of the most viable renewable resources for the world’s fuel and chemical feedstock needs. Currently ethanol derived from corn starch is the most common li...

  6. Forensic Analysis of a Contact Lens in a Murder Case.

    Science.gov (United States)

    Zwerling, Charles S

    2016-03-01

    Contact lenses have had rare relevance in trials and/or investigations. After 5 years of burial, orbital remnants were retrieved from an exhumed body and subsequently identified as a key piece of material evidence in a murder trial. The exhumed case materials were evaluated under laboratory conditions and were determined to be contact lens remnants. Contact lens fracture and burial simulation studies were performed to provide additional corroboration of the physical findings of the exhumed contact lens remnants. This material evidence was instrumental in providing factual proof refuting the defendant's testimony in the murder trial. A brief history of contact lens composition and use is provided for understanding the methods and observational results. This forensic case study represents the first published documentation of a contact lens from an exhumed body being used in a murder investigation and establishes an operational procedure for future forensic contact lens examinations. © 2016 American Academy of Forensic Sciences.

  7. Bilateral contact problem with adhesion and damage

    Directory of Open Access Journals (Sweden)

    Adel Aissaoui

    2014-05-01

    Full Text Available We study a mathematical problem describing the frictionless adhesive contact between a viscoelastic material with damage and a foundation. The adhesion process is modeled by a bonding field on the contact surface. The contact is bilateral and the tangential shear due to the bonding field is included. We establish a variational formulation for the problem and prove the existence and uniqueness of the solution. The existence of a unique weak solution for the problem is established using arguments of nonlinear evolution equations with monotone operators, a classical existence and uniqueness result for parabolic inequalities, and Banach's fixed point theorem.

  8. Enzyme loading dependence of cellulose hydrolysis of sugarcane bagasse

    Directory of Open Access Journals (Sweden)

    Carlos Martín

    2012-01-01

    Full Text Available The enzymatic hydrolysis of steam-pretreated sugarcane bagasse, either delignified or non-delignified, was studied as a function of enzyme loading. Hydrolysis experiments were carried out using five enzyme loadings (2.5 to 20 FPU/g cellulose and the concentration of solids was 2% for both materials. Alkaline delignification improved cellulose hydrolysis by increasing surface area. For both materials, glucose concentrations increased with enzyme loading. On the other hand, enzyme loadings higher than 15 FPU/g did not result in any increase in the initial rate, since the excess of enzyme adsorbed onto the substrate restricted the diffusion process through the structure.

  9. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... not been properly fitted by an eye care professional, the lenses stuck to my eye like a ... prescription and proper fitting by an eye-care professional. Retailers that sell contacts without a prescription are ...

  10. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... about the members of the eye-care team . Consumer warning about the improper use of colored contact ... About the Academy Jobs at the Academy Financial Relationships with Industry Medical Disclaimer Privacy Policy Terms of ...

  11. Contact Line Dynamics

    Science.gov (United States)

    Kreiss, Gunilla; Holmgren, Hanna; Kronbichler, Martin; Ge, Anthony; Brant, Luca

    2017-11-01

    The conventional no-slip boundary condition leads to a non-integrable stress singularity at a moving contact line. This makes numerical simulations of two-phase flow challenging, especially when capillarity of the contact point is essential for the dynamics of the flow. We will describe a modeling methodology, which is suitable for numerical simulations, and present results from numerical computations. The methodology is based on combining a relation between the apparent contact angle and the contact line velocity, with the similarity solution for Stokes flow at a planar interface. The relation between angle and velocity can be determined by theoretical arguments, or from simulations using a more detailed model. In our approach we have used results from phase field simulations in a small domain, but using a molecular dynamics model should also be possible. In both cases more physics is included and the stress singularity is removed.

  12. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... use of colored contact lenses , from the U.S. Food and Drug Administration (FDA). Are the colored lenses ... away without suffering an eye injury. However, the natural protective mechanisms of the eye – such as the ...

  13. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... about the members of the eye-care team . Consumer warning about the improper use of colored contact ... a laser pointer several times, according to a report published this month in the New England Journal ...

  14. SAM Technical Contacts

    Science.gov (United States)

    These technical contacts are available to help with questions regarding method deviations, modifications, sample problems or interferences, quality control requirements, the use of alternative methods, or the need to address analytes or sample types.

  15. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... colored contact lenses , from the U.S. Food and Drug Administration (FDA). Are the colored lenses you are ... this month in the New England Journal of Medicine. Unfortunately, this kind of injury is all too ...

  16. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... a souvenir shop, but 10 hours after she first put in a pair of colored contact lenses, ... APR 24, 2018 By Kate Rauch In a first, scientists in China have created artificial photoreceptors to ...

  17. GAS-FOVEAL CONTACT

    DEFF Research Database (Denmark)

    Alberti, Mark; la Cour, Morten

    2018-01-01

    PURPOSE: To compare gas-foveal contact in face-down positioning (FDP) and nonsupine positioning (NSP), to analyze causes of gas-foveal separation and to determine how gas-foveal contact affects clinical outcome after idiopathic macular hole repair. METHODS: Single center, randomized controlled...... study. Participants with an idiopathic macular hole were allocated to either FDP or NSP. Primary outcome was gas-foveal contact, calculated by analyzing positioning in relation to intraocular gas fill. Positioning was measured with an electronic device recording positioning for 72 hours postoperatively....... RESULTS: Positioning data were available for 33/35 in the FDP group and 35/37 in the NSP group, thus results are based on 68 analyzed participants. Median gas-foveal contact was 99.82% (range 73.6-100.0) in the FDP group and 99.57% (range 85.3-100.0) in the NSP group (P = 0.22). In a statistical model...

  18. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Sep. 26, 2013 It started as an impulsive buy from a souvenir shop, but 10 hours after ... are being sold illegally," Dr. Steinemann said. Never buy colored contact lenses from a retailer that does ...

  19. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... use of colored contact lenses , from the U.S. Food and Drug Administration (FDA). Are the colored lenses ... 2018 By Dan T. Gudgel Do you know what the difference is between ophthalmologists and optometrists? A ...

  20. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Halloween or any time of year, follow these guidelines: Get an eye exam from a licensed eye ... available in Spanish . Follow The Academy Professionals: Education Guidelines News Multimedia Public & Patients: Contact Us About the ...

  1. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... contacto de color Sep. 26, 2013 It started as an impulsive buy from a souvenir shop, but ... require the same level of care or consideration as a standard contact lens because they can be ...

  2. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... seek immediate medical attention from an ophthalmologist. Related resources: Learn how to properly care for contact lenses . ... have given blind patients some functional vision, using human embryonic stem cells. Two blind patients regained enough ...

  3. Colored Contact Lens Dangers

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    Full Text Available ... that decorative lenses do not require the same level of care or consideration as a standard contact ... By Kate Rauch In a small but intriguing study, scientists in England have given blind patients some ...

  4. Colored Contact Lens Dangers

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    Full Text Available ... MD, professor of ophthalmology at Case Western Reserve University in Cleveland. "This is far from the truth." Real People, Real Problems with Colored Contact Lenses Julian: Teenager Blinded In ...

  5. Colored Contact Lens Dangers

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    Full Text Available ... also available in Spanish . Follow The Academy Professionals: Education Guidelines News Multimedia Public & Patients: Contact Us About the Academy Jobs at the Academy Financial Relationships with Industry Medical Disclaimer Privacy Policy Terms ...

  6. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... lentes de contacto de color Sep. 26, 2013 It started as an impulsive buy from a souvenir ... Can Ruin Vision Eye Makeup Safety In fact, it is illegal to sell colored contact lenses without ...

  7. Colored Contact Lens Dangers

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    Full Text Available ... With Proper Contact Lens Care Apr 23, 2018 Solar Eclipse Inflicts Damage in the Shape of the ... edging closer, thanks to a wave of new technologies aiming to fix failing eye parts with human- ...

  8. Colored Contact Lens Dangers

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    Full Text Available ... valid prescription that includes the brand name, lens measurements, and expiration date. Purchase the colored contact lenses ... with human-made versions. U.S. News Highlights the Value of Ophthalmologists APR 20, 2018 By Dan T. ...

  9. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... sell contacts without a prescription are breaking the law, and may be fined $11,000 per violation. " ... Us About the Academy Jobs at the Academy Financial Relationships with Industry Medical Disclaimer Privacy Policy Terms ...

  10. Colored Contact Lens Dangers

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    Full Text Available ... sell contacts without a prescription are breaking the law, and may be fined $11,000 per violation. " ... 13, 2017 Histoplasmosis Diagnosis Sep 01, 2017 How common is retinal detachment for people with high myopia? ...

  11. Colored Contact Lens Dangers

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    Full Text Available ... Ophthalmology/Strabismus Ocular Pathology/Oncology Oculoplastics/Orbit Refractive Management/Intervention Retina/Vitreous Uveitis Focus ... Eye Health A-Z Symptoms Glasses & Contacts Tips & ...

  12. Colored Contact Lens Dangers

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    Full Text Available ... use of colored contact lenses , from the U.S. Food and Drug Administration (FDA). Are the colored lenses you are considering buying approved by the ... Service For Advertisers For Media Ophthalmology Job Center © American ...

  13. Colored Contact Lens Dangers

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    Full Text Available ... be purchased over-the-counter or on the Internet," says Thomas Steinemann, MD, professor of ophthalmology at ... also available in Spanish . Follow The Academy Professionals: Education Guidelines News Multimedia Public & Patients: Contact Us About ...

  14. Ergonomics SA: Contact

    African Journals Online (AJOL)

    Principal Contact. Mrs June McDougall. Rhodes University. Department of Human Kinetics and Ergonomics. P.O. Box 94. Rhodes University. Grahamstown. 6140. Phone: +27 46 6038471. Email: j.mcdougall@ru.ac.za ...

  15. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... contact lenses , from the U.S. Food and Drug Administration (FDA). Are the colored lenses you are considering buying approved by ... 23, 2018 Solar Eclipse Inflicts Damage in the Shape of ...

  16. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... had not been properly fitted by an eye care professional, the lenses stuck to my eye like ... lenses do not require the same level of care or consideration as a standard contact lens because ...

  17. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... colored contact lenses to enhance their costumes. From blood-drenched vampire eyes to glow-in-the-dark ... properly fitted may scratch the eye or cause blood vessels to grow into the cornea. Even if ...

  18. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... to the journals may be interrupted during this time. We are working to resolve the issue quickly ... like a suction cup." Halloween is a popular time for people to use colored contact lenses to ...

  19. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... the United States. All contact lenses are medical devices that require a prescription and proper fitting by ... Care Apr 23, 2018 How long does it take the eye to go back to its original ...

  20. Tomato contact dermatitis

    DEFF Research Database (Denmark)

    Paulsen, Evy; Christensen, Lars P; Andersen, Klaus Ejner

    2012-01-01

    The tomato plant (Solanum lycopersicum) is an important crop worldwide. Whereas immediate-type reactions to tomato fruits are well known, contact dermatitis caused by tomatoes or tomato plants is rarely reported. The aims of this study were to present new data on contact sensitization to tomato...... plants and review the literature on contact dermatitis caused by both plants and fruits. An ether extract of tomato plants made as the original oleoresin plant extracts, was used in aimed patch testing, and between 2005 and 2011. 8 of 93 patients (9%) tested positive to the oleoresin extracts....... This prevalence is in accordance with the older literature that reports tomato plants as occasional sensitizers. The same applies to tomato fruits, which, in addition, may cause protein contact dermatitis. The allergens of the plant are unknown, but both heat-stable and heat-labile constituents seem...

  1. Fragrance allergic contact dermatitis.

    Science.gov (United States)

    Cheng, Judy; Zug, Kathryn A

    2014-01-01

    Fragrances are a common cause of allergic contact dermatitis in Europe and in North America. They can affect individuals at any age and elicit a spectrum of reactions from contact urticaria to systemic contact dermatitis. Growing recognition of the widespread use of fragrances in modern society has fueled attempts to prevent sensitization through improved allergen identification, labeling, and consumer education. This review provides an overview and update on fragrance allergy. Part 1 discusses the epidemiology and evaluation of suspected fragrance allergy. Part 2 reviews screening methods, emerging fragrance allergens, and management of patients with fragrance contact allergy. This review concludes by examining recent legislation on fragrances and suggesting potential additions to screening series to help prevent and detect fragrance allergy.

  2. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Follow The Academy Professionals: Education Guidelines News Multimedia Public & Patients: Contact Us About the Academy Jobs at the Academy Financial Relationships with Industry Medical Disclaimer Privacy Policy Terms of Service For Advertisers For Media Ophthalmology ...

  3. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... be purchased over-the-counter or on the Internet," says Thomas Steinemann, MD, professor of ophthalmology at ... about the members of the eye-care team . Consumer warning about the improper use of colored contact ...

  4. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Peligros asociados con los lentes de contacto de color Sep. 26, 2013 It started as an impulsive ... Halloween is a popular time for people to use colored contact lenses to enhance their costumes. From ...

  5. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... The Academy Professionals: Education Guidelines News Multimedia Public & Patients: Contact Us About the Academy Jobs at the Academy Financial Relationships with Industry Medical Disclaimer Privacy Policy Terms of ...

  6. Colored Contact Lens Dangers

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    Full Text Available ... not require the same level of care or consideration as a standard contact lens because they can ... Us About the Academy Jobs at the Academy Financial Relationships with Industry Medical Disclaimer Privacy Policy Terms ...

  7. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... be purchased over-the-counter or on the Internet," says Thomas Steinemann, MD, professor of ophthalmology at ... ask for a prescription. There is no such thing as a "one size fits all" contact lens. ...

  8. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... also available in Spanish . Follow The Academy Professionals: Education Guidelines News Multimedia Public & Patients: Contact Us About the Academy Jobs at the Academy Financial Relationships with Industry Medical ...

  9. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Ophthalmology/Strabismus Ocular Pathology/Oncology Oculoplastics/Orbit Refractive Management/Intervention Retina/Vitreous Uveitis Focus ... Halloween Hazard: The Hidden Dangers of Buying Decorative Contact Lenses Without ...

  10. Enzymes for improved biomass conversion

    Science.gov (United States)

    Brunecky, Roman; Himmel, Michael E.

    2016-02-02

    Disclosed herein are enzymes and combinations of the enzymes useful for the hydrolysis of cellulose and the conversion of biomass. Methods of degrading cellulose and biomass using enzymes and cocktails of enzymes are also disclosed.

  11. Contact allergy to oak moss

    DEFF Research Database (Denmark)

    Bernard, Guillaume; Gimenéz-Arnau, Elena; Rastogi, Suresh Chandra

    2003-01-01

    In addition to pure synthetic fragrance materials several natural extracts are still in use in the perfume industry. Among them oak moss absolute, prepared from the lichen Evernia prunastri (L.) Arch., is considered a major contact sensitizer and is therefore included in the fragrance mix used...... for diagnosing perfume allergy. The process of preparing oak moss absolute has changed during recent years and, even though several potential sensitizers have been identified from former benzene extracts, its present constituents and their allergenic status are not clear. In the study reported here, we applied...

  12. Lettuce contact allergy.

    Science.gov (United States)

    Paulsen, Evy; Andersen, Klaus E

    2016-02-01

    Lettuce (Lactuca sativa L.) and its varieties are important vegetable crops worldwide. They are also well-known, rarely reported, causes of contact allergy. As lettuce allergens and extracts are not commercially available, the allergy may be underdiagnosed. The aims of this article are to present new data on lettuce contact allergy and review the literature. Lettuce is weakly allergenic, and occupational cases are mainly reported. Using aimed patch testing in Compositae-allergic patients, two recent Danish studies showed prevalence rates of positive lettuce reactions of 11% and 22%. The majority of cases are non-occupational, and may partly be caused by cross-reactivity. The sesquiterpene lactone mix seems to be a poor screening agent for lettuce contact allergy, as the prevalence of positive reactions is significantly higher in non-occupationally sensitized patients. Because of the easy degradability of lettuce allergens, it is recommended to patch test with freshly cut lettuce stem and supplement this with Compositae mix. As contact urticaria and protein contact dermatitis may present as dermatitis, it is important to perform prick-to-prick tests, and possibly scratch patch tests as well. Any person who is occupationally exposed to lettuce for longer periods, especially atopics, amateur gardeners, and persons keeping lettuce-eating pets, is potentially at risk of developing lettuce contact allergy. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. Immobilized enzymes and cells

    Energy Technology Data Exchange (ETDEWEB)

    Bucke, C; Wiseman, A

    1981-04-04

    This article reviews the current state of the art of enzyme and cell immobilization and suggests advances which might be made during the 1980's. Current uses of immobilized enzymes include the use of glucoamylase in the production of glucose syrups from starch and glucose isomerase in the production of high fructose corn syrup. Possibilities for future uses of immobilized enzymes and cells include the utilization of whey and the production of ethanol.

  14. Profiling the orphan enzymes

    Science.gov (United States)

    2014-01-01

    The emergence of Next Generation Sequencing generates an incredible amount of sequence and great potential for new enzyme discovery. Despite this huge amount of data and the profusion of bioinformatic methods for function prediction, a large part of known enzyme activities is still lacking an associated protein sequence. These particular activities are called “orphan enzymes”. The present review proposes an update of previous surveys on orphan enzymes by mining the current content of public databases. While the percentage of orphan enzyme activities has decreased from 38% to 22% in ten years, there are still more than 1,000 orphans among the 5,000 entries of the Enzyme Commission (EC) classification. Taking into account all the reactions present in metabolic databases, this proportion dramatically increases to reach nearly 50% of orphans and many of them are not associated to a known pathway. We extended our survey to “local orphan enzymes” that are activities which have no representative sequence in a given clade, but have at least one in organisms belonging to other clades. We observe an important bias in Archaea and find that in general more than 30% of the EC activities have incomplete sequence information in at least one superkingdom. To estimate if candidate proteins for local orphans could be retrieved by homology search, we applied a simple strategy based on the PRIAM software and noticed that candidates may be proposed for an important fraction of local orphan enzymes. Finally, by studying relation between protein domains and catalyzed activities, it appears that newly discovered enzymes are mostly associated with already known enzyme domains. Thus, the exploration of the promiscuity and the multifunctional aspect of known enzyme families may solve part of the orphan enzyme issue. We conclude this review with a presentation of recent initiatives in finding proteins for orphan enzymes and in extending the enzyme world by the discovery of new

  15. Enzymes - important players in green chemistry

    Directory of Open Access Journals (Sweden)

    Agata Tarczykowska

    2017-09-01

    Full Text Available Green chemistry has become a worldwide approach that leads to sustainable growth through application and development of its principles. A lot of work has to be put into designing new processes comprising of materials which do not emit pollutants to the atmosphere. Inventing new safer methods and finding less harmful products can be challenging. Enzymes are a great hope of scientists in the field of green chemistry. Enzymes as catalysts require mild conditions therefore it is a great way of saving resources such as energy or water. Processes with the use of enzymes have become more feasible by being more cost effective and eco friendly. Taking into account the benefits of green chemistry, enzyme biocatalysis has quickly replaced traditional chemical processes in several fields, and this substitution is going to reach even more areas because of new emerging technologies in enzyme engineering.

  16. Fungal enzymes in the attine ant symbiosis

    DEFF Research Database (Denmark)

    de Fine Licht, Henrik Hjarvard; Schiøtt, Morten; Boomsma, Jacobus Jan

    the more basal attine genera use substrates such as flowers, plant debris, small twigs, insect feces and insect carcasses. This diverse array of fungal substrates across the attine lineage implies that the symbiotic fungus needs different enzymes to break down the plant material that the ants provide...... or different efficiencies of enzyme function. Fungal enzymes that degrade plant cell walls may have functionally co-evolved with the ants in this scenario. We explore this hypothesis with direct measurements of enzyme activity in fungus gardens in 12 species across 8 genera spanning the entire phylogeny...... and diversity of life-styles within the attine clade. We find significant differences in enzyme activity between different genera and life-styles of the ants. How these findings relate to attine ant coevolution and crop optimization are discussed....

  17. Occupational contact dermatitis in painters - an analysis of patch test data from the Danish Contact Dermatitis Group

    DEFF Research Database (Denmark)

    Mose, Anja P; Lundov, Michael Dyrgaard; Zachariae, Claus

    2012-01-01

    Background. Painters are among the occupational groups that most commonly experience occupational contact dermatitis, but few investigations exist concerning this occupation. Objectives. To characterize painters with contact dermatitis and identify the most common allergens associated...... with the occupation. Materials and methods. All patch test results of 219 painters and 1095 matched controls registered by the Danish Contact Dermatitis Group between 2001 and 2010 were analysed. Results. Hand eczema (p contact dermatitis (p

  18. Substrates and method for determining enzymes

    Science.gov (United States)

    Smith, R.E.; Bissell, E.R.

    1981-10-13

    A method is disclosed for determining the presence of an enzyme in a biological fluid, which includes the steps of contacting the fluid with a synthetic chromogenic substrate, which is an amino acid derivative of 7-amino-4-trifluoromethylcoumarin; incubating the substrate-containing fluid to effect enzymatic hydrolysis; and fluorometrically determining the presence of the free 7-amino-4-trifluoromethylcoumarin chromophore in the hydrolyzate. No Drawings

  19. Patients with multiple contact allergies

    DEFF Research Database (Denmark)

    Carlsen, Berit Christina; Andersen, Klaus Ejner; Menné, Torkil

    2008-01-01

    Patients with multiple contact allergies, also referred to as polysensitized, are more frequent than predicted from prevalence of single sensitivities. The understanding of why some people develop multiple contact allergies, and characterization of patients with multiple contact allergies...... of developing multiple contact allergies. Evidence of allergen clusters among polysensitized individuals is also reviewed. The literature supports the idea that patients with multiple contact allergies constitute a special entity within the field of contact allergy. There is no generally accepted definition...... of patients with multiple contact allergies. We suggest that contact allergy to 3 or more allergens are defined as multiple contact allergies....

  20. Immobilised enzymes in biorenewables production.

    Science.gov (United States)

    Franssen, Maurice C R; Steunenberg, Peter; Scott, Elinor L; Zuilhof, Han; Sanders, Johan P M

    2013-08-07

    Oils, fats, carbohydrates, lignin, and amino acids are all important raw materials for the production of biorenewables. These compounds already play an important role in everyday life in the form of wood, fabrics, starch, paper and rubber. Enzymatic reactions do, in principle, allow the transformation of these raw materials into biorenewables under mild and sustainable conditions. There are a few examples of processes using immobilised enzymes that are already applied on an industrial scale, such as the production of High-Fructose Corn Syrup, but these are still rather rare. Fortunately, there is a rapid expansion in the research efforts that try to improve this, driven by a combination of economic and ecological reasons. This review focusses on those efforts, by looking at attempts to use fatty acids, carbohydrates, proteins and lignin (and their building blocks), as substrates in the synthesis of biorenewables using immobilised enzymes. Therefore, many examples (390 references) from the recent literature are discussed, in which we look both at the specific reactions as well as to the methods of immobilisation of the enzymes, as the latter are shown to be a crucial factor with respect to stability and reuse. The applications of the renewables produced in this way range from building blocks for the pharmaceutical and polymer industry, transport fuels, to additives for the food industry. A critical evaluation of the relevant factors that need to be improved for large-scale use of these examples is presented in the outlook of this review.

  1. Contact engineering for nano-scale CMOS

    KAUST Repository

    Hussain, Muhammad Mustafa

    2012-09-10

    High performance computation with longer battery lifetime is an essential component in our today\\'s digital electronics oriented life. To achieve these goals, field effect transistors based complementary metal oxide semiconductor play the key role. One of the critical requirements of transistor structure and fabrication is efficient contact engineering. To catch up with high performance information processing, transistors are going through continuous scaling process. However, it also imposes new challenges to integrate good contact materials in a small area. This can be counterproductive as smaller area results in higher contact resistance thus reduced performance for the transistor itself. At the same time, discovery of new one or two-dimensional materials like nanowire, nanotube, or atomic crystal structure materials, introduces new set of challenges and opportunities. In this paper, we are reviewing them in a synchronized fashion: fundamentals of contact engineering, evolution into non-planar field effect transistors, opportunities and challenges with one and two-dimensional materials and a new opportunity of contact engineering from device architecture perspective. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. The role of contacts in semiconductor gamma radiation detectors

    International Nuclear Information System (INIS)

    Lachish, U.

    1998-01-01

    It is proposed that the operation of semiconductor gamma radiation detectors, equipped with ohmic contacts, which allow free electron flow between the contacts and bulk material, will not be sensitive to low hole mobility, hole collection efficiency, or hole trapping. Such fast-operating detectors may be readily integrated into monolithic arrays. The detection mechanism and various material aspects are discussed and compared to those of blocking contact detectors. Some suggestions for detector realization are presented. (orig.)

  3. Metrological aspects of enzyme production

    International Nuclear Information System (INIS)

    Kerber, T M; Pereira-Meirelles, F V; Dellamora-Ortiz, G M

    2010-01-01

    Enzymes are frequently used in biotechnology to carry out specific biological reactions, either in industrial processes or for the production of bioproducts and drugs. Microbial lipases are an important group of biotechnologically valuable enzymes that present widely diversified applications. Lipase production by microorganisms is described in several published papers; however, none of them refer to metrological evaluation and the estimation of the uncertainty in measurement. Moreover, few of them refer to process optimization through experimental design. The objectives of this work were to enhance lipase production in shaken-flasks with Yarrowia lipolytica cells employing experimental design and to evaluate the uncertainty in measurement of lipase activity. The highest lipolytic activity obtained was about three- and fivefold higher than the reported activities of CRMs BCR-693 and BCR-694, respectively. Lipase production by Y. lipolytica cells aiming the classification as certified reference material is recommended after further purification and stability studies

  4. Transparent contacts for stacked compound photovoltaic cells

    Science.gov (United States)

    Tauke-Pedretti, Anna; Cederberg, Jeffrey; Nielson, Gregory N.; Okandan, Murat; Cruz-Campa, Jose Luis

    2016-11-29

    A microsystems-enabled multi-junction photovoltaic (MEM-PV) cell includes a first photovoltaic cell having a first junction, the first photovoltaic cell including a first semiconductor material employed to form the first junction, the first semiconductor material having a first bandgap. The MEM-PV cell also includes a second photovoltaic cell comprising a second junction. The second photovoltaic cell comprises a second semiconductor material employed to form the second junction, the second semiconductor material having a second bandgap that is less than the first bandgap, the second photovoltaic cell further comprising a first contact layer disposed between the first junction of the first photovoltaic cell and the second junction of the second photovoltaic cell, the first contact layer composed of a third semiconductor material having a third bandgap, the third bandgap being greater than or equal to the first bandgap.

  5. Contact angle studies on anodic porous alumina.

    Science.gov (United States)

    Redón, Rocío; Vázquez-Olmos, A; Mata-Zamora, M E; Ordóñez-Medrano, A; Rivera-Torres, F; Saniger, J M

    2005-07-15

    The preparation of nanostructures using porous anodic aluminum oxide (AAO) as templates involves the introduction of dissolved materials into the pores of the membranes; one way to determine which materials are preferred to fill the pores involves the measurement of the contact angles (theta) of different solvents or test liquids on the AAOs. Thus, we present measurements of contact angles of nine solvents on four different AAO sheets by tensiometric and goniometric methods. From the solvents tested, we found dimethyl sulfoxide (DMSO) and N,N(')-dimethylformamide (DMF) to interact with the AAOs, the polarity of the solvents and the surfaces being the driving force.

  6. Enzyme Engineering for In Situ Immobilization.

    Science.gov (United States)

    Rehm, Fabian B H; Chen, Shuxiong; Rehm, Bernd H A

    2016-10-14

    Enzymes are used as biocatalysts in a vast range of industrial applications. Immobilization of enzymes to solid supports or their self-assembly into insoluble particles enhances their applicability by strongly improving properties such as stability in changing environments, re-usability and applicability in continuous biocatalytic processes. The possibility of co-immobilizing various functionally related enzymes involved in multistep synthesis, conversion or degradation reactions enables the design of multifunctional biocatalyst with enhanced performance compared to their soluble counterparts. This review provides a brief overview of up-to-date in vitro immobilization strategies while focusing on recent advances in enzyme engineering towards in situ self-assembly into insoluble particles. In situ self-assembly approaches include the bioengineering of bacteria to abundantly form enzymatically active inclusion bodies such as enzyme inclusions or enzyme-coated polyhydroxyalkanoate granules. These one-step production strategies for immobilized enzymes avoid prefabrication of the carrier as well as chemical cross-linking or attachment to a support material while the controlled oriented display strongly enhances the fraction of accessible catalytic sites and hence functional enzymes.

  7. Enzymes from Higher Eukaryotes for Industrial Biocatalysis

    Directory of Open Access Journals (Sweden)

    Zhibin Liu

    2004-01-01

    Full Text Available The industrial production of fine chemicals, feed and food ingredients, pharmaceuticals, agrochemicals and their respective intermediates relies on an increasing application of biocatalysis, i.e. on enzyme or whole-cell catalyzed conversions of molecules. Simple procedures for discovery, cloning and over-expression as well as fast growth favour fungi, yeasts and especially bacteria as sources of biocatalysts. Higher eukaryotes also harbour an almost unlimited number of potential biocatalysts, although to date the limited supply of enzymes, the high heterogeneity of enzyme preparations and the hazard of infectious contaminants keep some interesting candidates out of reach for industrial bioprocesses. In the past only a few animal and plant enzymes from agricultural waste materials were employed in food processing. The use of bacterial expression strains or non-conventional yeasts for the heterologous production of efficient eukaryotic enzymes can overcome the bottleneck in enzyme supply and provide sufficient amounts of homogenous enzyme preparations for reliable and economically feasible applications at large scale. Ideal enzymatic processes represent an environmentally friendly, »near-to-completion« conversion of (mostly non-natural substrates to pure products. Recent developments demonstrate the commercial feasibility of large-scale biocatalytic processes employing enzymes from higher eukaryotes (e.g. plants, animals and also their usefulness in some small-scale industrial applications.

  8. Artificial Enzymes, "Chemzymes"

    DEFF Research Database (Denmark)

    Bjerre, Jeannette; Rousseau, Cyril Andre Raphaël; Pedersen, Lavinia Georgeta M

    2008-01-01

    Enzymes have fascinated scientists since their discovery and, over some decades, one aim in organic chemistry has been the creation of molecules that mimic the active sites of enzymes and promote catalysis. Nevertheless, even today, there are relatively few examples of enzyme models that successf......Enzymes have fascinated scientists since their discovery and, over some decades, one aim in organic chemistry has been the creation of molecules that mimic the active sites of enzymes and promote catalysis. Nevertheless, even today, there are relatively few examples of enzyme models...... that successfully perform Michaelis-Menten catalysis under enzymatic conditions (i.e., aqueous medium, neutral pH, ambient temperature) and for those that do, very high rate accelerations are seldomly seen. This review will provide a brief summary of the recent developments in artificial enzymes, so called...... "Chemzymes", based on cyclodextrins and other molecules. Only the chemzymes that have shown enzyme-like activity that has been quantified by different methods will be mentioned. This review will summarize the work done in the field of artificial glycosidases, oxidases, epoxidases, and esterases, as well...

  9. Magnetically responsive enzyme powders

    Energy Technology Data Exchange (ETDEWEB)

    Pospiskova, Kristyna, E-mail: kristyna.pospiskova@upol.cz [Regional Centre of Advanced Technologies and Materials, Palacky University, Slechtitelu 11, 783 71 Olomouc (Czech Republic); Safarik, Ivo, E-mail: ivosaf@yahoo.com [Regional Centre of Advanced Technologies and Materials, Palacky University, Slechtitelu 11, 783 71 Olomouc (Czech Republic); Department of Nanobiotechnology, Institute of Nanobiology and Structural Biology of GCRC, Na Sadkach 7, 370 05 Ceske Budejovice (Czech Republic)

    2015-04-15

    Powdered enzymes were transformed into their insoluble magnetic derivatives retaining their catalytic activity. Enzyme powders (e.g., trypsin and lipase) were suspended in various liquid media not allowing their solubilization (e.g., saturated ammonium sulfate and highly concentrated polyethylene glycol solutions, ethanol, methanol, 2-propanol) and subsequently cross-linked with glutaraldehyde. Magnetic modification was successfully performed at low temperature in a freezer (−20 °C) using magnetic iron oxides nano- and microparticles prepared by microwave-assisted synthesis from ferrous sulfate. Magnetized cross-linked enzyme powders were stable at least for two months in water suspension without leakage of fixed magnetic particles. Operational stability of magnetically responsive enzymes during eight repeated reaction cycles was generally without loss of enzyme activity. Separation of magnetically modified cross-linked powdered enzymes from reaction mixtures was significantly simplified due to their magnetic properties. - Highlights: • Cross-linked enzyme powders were prepared in various liquid media. • Insoluble enzymes were magnetized using iron oxides particles. • Magnetic iron oxides particles were prepared by microwave-assisted synthesis. • Magnetic modification was performed under low (freezing) temperature. • Cross-linked powdered trypsin and lipase can be used repeatedly for reaction.

  10. Targeted enzyme prodrug therapies.

    Science.gov (United States)

    Schellmann, N; Deckert, P M; Bachran, D; Fuchs, H; Bachran, C

    2010-09-01

    The cure of cancer is still a formidable challenge in medical science. Long-known modalities including surgery, chemotherapy and radiotherapy are successful in a number of cases; however, invasive, metastasized and inaccessible tumors still pose an unresolved and ongoing problem. Targeted therapies designed to locate, detect and specifically kill tumor cells have been developed in the past three decades as an alternative to treat troublesome cancers. Most of these therapies are either based on antibody-dependent cellular cytotoxicity, targeted delivery of cytotoxic drugs or tumor site-specific activation of prodrugs. The latter is a two-step procedure. In the first step, a selected enzyme is accumulated in the tumor by guiding the enzyme or its gene to the neoplastic cells. In the second step, a harmless prodrug is applied and specifically converted by this enzyme into a cytotoxic drug only at the tumor site. A number of targeting systems, enzymes and prodrugs were investigated and improved since the concept was first envisioned in 1974. This review presents a concise overview on the history and latest developments in targeted therapies for cancer treatment. We cover the relevant technologies such as antibody-directed enzyme prodrug therapy (ADEPT), gene-directed enzyme prodrug therapy (GDEPT) as well as related therapies such as clostridial- (CDEPT) and polymer-directed enzyme prodrug therapy (PDEPT) with emphasis on prodrug-converting enzymes, prodrugs and drugs.

  11. Enzymes in Fermented Fish.

    Science.gov (United States)

    Giyatmi; Irianto, H E

    Fermented fish products are very popular particularly in Southeast Asian countries. These products have unique characteristics, especially in terms of aroma, flavor, and texture developing during fermentation process. Proteolytic enzymes have a main role in hydrolyzing protein into simpler compounds. Fermentation process of fish relies both on naturally occurring enzymes (in the muscle or the intestinal tract) as well as bacteria. Fermented fish products processed using the whole fish show a different characteristic compared to those prepared from headed and gutted fish. Endogenous enzymes like trypsin, chymotrypsin, elastase, and aminopeptidase are the most involved in the fermentation process. Muscle tissue enzymes like cathepsins, peptidases, transaminases, amidases, amino acid decarboxylases, glutamic dehydrogenases, and related enzymes may also play a role in fish fermentation. Due to the decreased bacterial number during fermentation, contribution of microbial enzymes to proteolysis may be expected prior to salting of fish. Commercial enzymes are supplemented during processing for specific purposes, such as quality improvement and process acceleration. In the case of fish sauce, efforts to accelerate fermentation process and to improve product quality have been studied by addition of enzymes such as papain, bromelain, trypsin, pepsin, and chymotrypsin. © 2017 Elsevier Inc. All rights reserved.

  12. Estimation of contact resistance in proton exchange membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Lianhong; Liu, Ying; Song, Haimin; Wang, Shuxin [School of Mechanical Engineering, Tianjin University, 92 Weijin Road, Nankai District, Tianjin 300072 (China); Zhou, Yuanyuan; Hu, S. Jack [Department of Mechanical Engineering, The University of Michigan, Ann Arbor, MI 48109-2125 (United States)

    2006-11-22

    The contact resistance between the bipolar plate (BPP) and the gas diffusion layer (GDL) is an important factor contributing to the power loss in proton exchange membrane (PEM) fuel cells. At present there is still not a well-developed method to estimate such contact resistance. This paper proposes two effective methods for estimating the contact resistance between the BPP and the GDL based on an experimental contact resistance-pressure constitutive relation. The constitutive relation was obtained by experimentally measuring the contact resistance between the GDL and a flat plate of the same material and processing conditions as the BPP under stated contact pressure. In the first method, which was a simplified prediction, the contact area and contact pressure between the BPP and the GDL were analyzed with a simple geometrical relation and the contact resistance was obtained by the contact resistance-pressure constitutive relation. In the second method, the contact area and contact pressure between the BPP and GDL were analyzed using FEM and the contact resistance was computed for each contact element according to the constitutive relation. The total contact resistance was then calculated by considering all contact elements in parallel. The influence of load distribution on contact resistance was also investigated. Good agreement was demonstrated between experimental results and predictions by both methods. The simplified prediction method provides an efficient approach to estimating the contact resistance in PEM fuel cells. The proposed methods for estimating the contact resistance can be useful in modeling and optimizing the assembly process to improve the performance of PEM fuel cells. (author)

  13. Rough Surface Contact

    Directory of Open Access Journals (Sweden)

    T Nguyen

    2017-06-01

    Full Text Available This paper studies the contact of general rough curved surfaces having nearly identical geometries, assuming the contact at each differential area obeys the model proposed by Greenwood and Williamson. In order to account for the most general gross geometry, principles of differential geometry of surface are applied. This method while requires more rigorous mathematical manipulations, the fact that it preserves the original surface geometries thus makes the modeling procedure much more intuitive. For subsequent use, differential geometry of axis-symmetric surface is considered instead of general surface (although this “general case” can be done as well in Chapter 3.1. The final formulas for contact area, load, and frictional torque are derived in Chapter 3.2.

  14. Shoe allergic contact dermatitis.

    Science.gov (United States)

    Matthys, Erin; Zahir, Amir; Ehrlich, Alison

    2014-01-01

    Foot dermatitis is a widespread condition, affecting men and women of all ages. Because of the location, this condition may present as a debilitating problem to those who have it. Allergic contact dermatitis involving the feet is frequently due to shoes or socks. The allergens that cause shoe dermatitis can be found in any constituent of footwear, including rubber, adhesives, leather, dyes, metals, and medicaments. The goal of treatment is to identify and minimize contact with the offending allergen(s). The lack of product information released from shoe manufacturers and the continually changing trends in footwear present a challenge in treating this condition. The aim of this study is to review the current literature on allergic contact shoe dermatitis; clinical presentation, allergens, patch testing, and management will be discussed. PubMed and MEDLINE databases were used for the search, with a focus on literature updates from the last 15 years.

  15. ALLERGIC CONTACT DERMATITIS

    Directory of Open Access Journals (Sweden)

    Trisna Yuliharti Tersinanda

    2013-07-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE Allergic contact dermatitis is an immunologic reaction that tends to involve the surrounding skin and may even spread beyond affected sites. This skin disease is one of the more frequent, and costly dermatologic problems. Recent data from United Kingdom and United States suggest that the percentage of occupational contact dermatitis due to allergy may be much higher, thus raising the economic impact of occupational allergic contact dermatitis. There is not enough data about the epidemiology of allergic contact dermatitis in Indonesia, however based on research that include beautician in Denpasar, about 27,6 percent had side effect of cosmetics, which is 25,4 percent of it manifested as allergic contact dermatitis. Diagnosis of allergic contact dermatitis is based on anamnesis, physical examination, patch test, and this disease should be distinguished from other eczematous skin disease. The management is prevention of allergen exposure, symptomatic treatment, and physicochemical barrier /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

  16. Contact traction analysis for profile change during coining process

    International Nuclear Information System (INIS)

    Kim, Hyung Kyu; Yoon, Kyung Ho; Kang, Heung Seok; Song, Kee Nam

    2002-01-01

    Contact tractions are analysed in the case of the change in contact profile occurring during the coining process of a thin strip material. The changed profile is assumed as a concave circular arc in the central part of the contact region which is smoothly connected with convex circular arcs at both sides, referring to the actual measurement of the coined material. The profile is discretized and the known solutions of singular integral equations are used. Since the contact profile affects the contact traction and relevant tribological behaviour (e.g. wear) as well, an accurate definition of the profile is necessary in the analysis of material failure. Parametric study is conducted with the variation of the radii and distance of the arcs, which defines the height difference between the summits of the arcs. Considered is the contact profile, which can give the negligible variation of the traction in comparison with that before the coining process

  17. Lithium-drifted silicon detector with segmented contacts

    Science.gov (United States)

    Tindall, Craig S.; Luke, Paul N.

    2006-06-13

    A method and apparatus for creating both segmented and unsegmented radiation detectors which can operate at room temperature. The devices include a metal contact layer, and an n-type blocking contact formed from a thin layer of amorphous semiconductor. In one embodiment the material beneath the n-type contact is n-type material, such as lithium compensated silicon that forms the active region of the device. The active layer has been compensated to a degree at which the device may be fully depleted at low bias voltages. A p-type blocking contact layer, or a p-type donor material can be formed beneath a second metal contact layer to complete the device structure. When the contacts to the device are segmented, the device is capable of position sensitive detection and spectroscopy of ionizing radiation, such as photons, electrons, and ions.

  18. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Spanish . Follow The Academy Professionals: Education Guidelines News Multimedia Public & Patients: Contact Us About the Academy Jobs at the Academy Financial Relationships with Industry Medical Disclaimer Privacy Policy Terms of Service For Advertisers For Media Ophthalmology Job Center © American ...

  19. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Tips & Prevention News Ask an Ophthalmologist Patient Stories Español Eye Health / News Halloween Hazard: The Hidden Dangers ... Decorative Contact Lenses Without a Prescription Leer en Español: Peligros asociados con los lentes de contacto de ...

  20. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... prescription. There is no such thing as a "one size fits all" contact lens. Lenses that are not properly fitted may scratch the eye or cause blood vessels to grow into the cornea. Even if you have perfect vision, you need to get an eye exam and a prescription ...